transmission - Search Results
Articles About transmission
Articles are sorted by RELEVANCE. Sort by Date.
A best practice in gear design is to limit the amount of backlash to a minimum value needed to accommodate manufacturing tolerances, misalignments, and deflections, in order to prevent the non-driving side of the teeth to make contact and rattle. Industry standards, such as ANSI/AGMA 2002 and DIN3967, provide reference values of minimum backlash to be used in the gear design. However, increased customers' expectations in vehicle noise eduction have pushed backlash and allowable manufacturing tolerances to even lower limits. This is especially true in the truck market, where engines are quieter because they run at lower speeds to improve fuel economy, but they quite often run at high torsional vibration levels. Furthermore, gear and shaft arrangements in truck transmissions have become more complex due to increased number of speeds and to improve efficiency. Determining the minimum amount of backlash is quite a challenge. This paper presents an investigation of minimum backlash values of helical gear teeth applied to a light-duty pickup truck transmission. An analytical model was developed to calculate backlash limits of each gear pair when not transmitting load, and thus susceptible to generate rattle noise, through different transmission power paths. A statistical approach (Monte Carlo) was used since a significant number of factors affect backlash, such as tooth thickness variation; center distance variation; lead; runout and pitch variations; bearing clearances; spline clearances; and shaft deflections and misalignments. Analytical results identified the critical gear pair, and power path, which was confirmed experimentally on a transmission. The approach presented in this paper can be useful to design gear pairs with a minimum amount of backlash, to prevent double flank contact and to help reduce rattle noise to lowest levels.
An investigation of transmission errors and bearing contact of spur, helical, and spiral bevel gears was performed. Modified tooth surfaces for these gears have been proposed in order to absorb linear transmission errors caused by gear misalignment and to localize the bearing contact. Numerical examples for spur, helical, and spiral bevel gears are presented to illustrate the behavior of the modified gear surfaces with respect to misalignment and errors of assembly. The numerical results indicate that the modified surfaces will perform with a low level of transmission error in non-ideal operating environments.
There's never been a better time to put the spotlight on e-drive transmissions and electric vehicles. They're obviously not just coming: they're already here. Just check out any auto show or showroom. That's why Gear Technology magazine is pleased to present the first installment in a series of chapters excerpted from Dr. Hermann J. Stadtfeld's newest book, "E-Drive Transmission Guide - New solutions for electric- and hybrid transmission vehicles."
When you push 850 horsepower and 9,000 rpm through a racing transmission, you better hope it stands up. Transmission cases and gears strewn all over the racetrack do nothing to enhance your standing, nor that of your transmission supplier.
With all the work in transmission development these days, the demand for automobile transmission gears should remain strong for several years, but suppliers will have to be as flexible as possible to keep up with the changes.
Which transmission system will come out on top is a hot topic in the automotive community. With multiple transmission-centric conferences on the horizon, there will be plenty of debate, but how much will the answer actually affect gear manufacturers, and when?
Conical involute gears (beveloids) are used in transmissions with intersecting or skewed axes and for backlash-free transmissions with parallel axes.
Profile corrections on gears are a commonly used method to reduce transmission error, contact shock, and scoring risk. There are different types of profile corrections. It is a known fact that the type of profile correction used will have a strong influence on the resulting transmission error. The degree of this influence may be determined by calculating tooth loading during mesh. The current method for this calculation is very complicated and time consuming; however, a new approach has been developed that could reduce the calculation time.
By increasing the number of gears and the transmission-ratio spread, the engine will run with better fuel efficiency and without loss of driving dynamics. Transmission efficiency itself can be improved by: using fuelefficient transmission oil; optimizing the lubrication systems and pumps; improving shifting strategies and optimizing gearings; and optimizing bearings and seals/gaskets.
The connection between transmission error, noise and vibration during operation has long been established. Calculation methods have been developed to describe the influence so that it is possible to evaluate the relative effect of applying a specific modification at the design stage. These calculations enable the designer to minimize the excitation from the gear pair engagement at a specific load. This paper explains the theory behind transmission error and the reasoning behind the method of applying the modifications through mapping surface profiles and determining load sharing.
Question: I am a gear engineer for a motor manufacturer in China. I am writing about noise generated from cross-helical gear assembly error. I want to learn the relationship between the misalignment (center distance change and cross-angle shift) and transmission error. It is better under the loading and theory conditions. What is the trend of cross-helical gear development (use ZI worm and involute helical gear, point contact)?
Solutions to the governing equations of a spur gear transmission model, developed in a previous article are presented. Factors affecting the dynamic load are identified. It is found that the dynamic load increases with operating speed up to a system natural frequency. At operating speeds beyond the natural frequency the dynamic load decreases dramatically. Also, it is found that the transmitted load and shaft inertia have little effect upon the total dynamic load. Damping and friction decrease the dynamic load. Finally, tooth stiffness has a significant effect upon dynamic loadings the higher the stiffness, the lower the dynamic loading. Also, the higher the stiffness, the higher the rotating speed required for peak dynamic response.
The concept of "transmission error" is relatively new and stems from research work in the late 1950s by Gregory, Harris and Munro,(1) together with the need to check the accuracy of gear cutting machines. The corresponding commercial "single flank" testing equipment became available in the 1960s, but it was not until about ten years ago that it became generally used, and only recently has it been possible to test reliably at full load and full speed.
Vehicle gear noise testing is a complex and often misunderstood subject. Gear noise is really a system problem.(1) most gearing used for power transmission is enclosed in a housing and, therefore, little or no audible sound is actually heard from the gear pair.(2) The vibrations created by the gears are amplified by resonances of structural elements. This amplification occurs when the speed of the gear set is such that the meshing frequency or a multiply of it is equal to a natural frequency of the system in which the gears are mounted.
In the design process of transmissions, one major criterion is the resulting noise emission of the powertrain due to gear excitation. Within the past years, much investigation has shown that the noise emission can be attributed to quasi-static transmission error. Therefore, the transmission error can be used for a tooth contact analysis in the design process, as well as a characteristic value for quality assurance by experimental inspections.
This paper presents an approach that provides optimization of both gearbox kinematic arrangement and gear tooth geometry to achieve a high-density gear transmission. It introduces dimensionless gearbox volume functions that can be minimized by the internal gear ratio optimization. Different gearbox arrangements are analyzed to define a minimum of the volume functions. Application of asymmetric gear tooth profiles for power density maximization is also considered.
The first chapter from a new book by Dr. Hermann J. Stadtfeld provides an overview of the need for new technologies and approaches when it comes to developing transmissions for electric vehicles.
In some gear dynamic models, the effect of tooth flexibility is ignored when the model determines which pairs of teeth are in contact. Deflection of loaded teeth is not introduced until the equations of motion are solved. This means the zone of tooth contact and average tooth meshing stiffness are underestimated, and the individual tooth load is overstated, especially for heavily loaded gears. This article compares the static transmission error and dynamic load of heavily loaded, low-contact-ratio spur gears when the effect of tooth flexibility has been considered and when it has been ignored. Neglecting the effect yields an underestimate of resonance speeds and an overestimate of the dynamic load.
Minimizing gear losses caused by churning, windage and mesh friction is important if plant operating costs and environmental impact are to be minimized. This paper concentrates on mesh friction losses and associated scuffing risk. It describes the preliminary results from using a validated, 3-D Finite Element Analysis (FEA) and Tooth Contact Analysis (TCA) program to optimize cylindrical gears for low friction losses without compromising transmission error (TE), noise and power density. Some case studies and generic procedures for minimizing losses are presented. Future development and further validation work is discussed.
Pericyclic transmissions: how they work.
Given the lack of information on thermal distortion effects in small size steel gears, an experimental study of quasi-static transmission error behavior under thermomechanical conditions is presented.
AGMA925â€“A03 scuffing risk predictions for a series of spur and helical gear sets of transmissions used in commercial vehicles ranging from SAE Class 3 through Class 8.
News from the major automakers and transmission suppliers.
Gleason 350GMS helps put higher quality, more reliable gears into its next-generation TC10 automatic transmission.
In the field of large power transmission gear units for heavy machine industry, the following two development trends have been highly influential: use of case hardened gears and a branching of the power flow through two or more ways.
Universal tractor transmission oil (UTTO) is multifunctional tractor oil formulated for use in transmissions, final drives, differentials, wet brakes, and hydraulic systems of farm tractors employing a common oil reservoir. In the present work, the gear protection properties of two formulated vegetable-based UTTO oils, one synthetic ester-based UTTO oil, one synthetic ester gear oil, and one mineral based UTTO oil are investigated.
Almost any external tooth form that is uniformly spaced around a center can be hobbed. Hobbing is recognized as an economical means of producing spur and helical gears with involute tooth profiles.
In a modern truck, the gear teeth are among the most stressed parts. Failure of a tooth will damage the transmission severely. Throughout the years, gear design experience has been gained and collected into standards such as DIN (Ref. 1) or AGMA (Ref. 2). Traditionally two types of failures are considered in gear design: tooth root bending fatigue, and contact fatigue. The demands for lighter and more silent transmissions have given birth to new failure types. One novel failure type, Tooth Interior Fatigue Fracture (TIFF), has previously been described by MackAldener and Olsson (Refs. 3 & 4) and is further explored in this paper.
In July of 1996 we introduced the gear community to the Internet in these pages through the Gear Industry Home Page (GIHP). This electronic buyers guide for gear machine tools, tooling, accessories and services has proven to be more popular than we could have envisioned. In our first month, we had over 3,000 hits, and in our third month, we have over 4,500. By our fourth month, we topped the 7,000 mark, and we are on our way to 11,000 hits in November. As our advertisers develop their own home sites in order to offer layers of information about their companies, their products and services, we expect this activity will increase even more.
The data discussed in this article was taken from an upright vacuum cleaner. This was a prototype cleaner that was self-propelled by a geared transmission. It was the first time that the manufacturer had used a geared transmission in this application.
When Belgium-based Hansen Transmissions was under the ownership of Invensys plc in the late 1990s, the parent company was dropping not-so-subtle hints that the industrial gearbox manufacturer was not part of its long-term plans. Yet Hansenâ€™s CEO Ivan Brems never dreamed that, less than a decade later, he would be working for an Indian company.
Recently, there has been increased interest in the dynamic effects in gear systems. This interest is stimulated by demands for stronger, higher speed, improved performance, and longer-lived systems. This in turn had stimulated numerous research efforts directed toward understanding gear dynamic phenomena. However, many aspects of gear dynamics are still not satisfactorily understood.
Electrification has already started to have a noticeable impact on the global automotive industry. As a result, the drivetrains of hybrid (HEV) and full electric vehicles (EV) are facing many challenges, like increased requirements for NVH in high speed e-Drives and the need for performance improvements to deal with recuperation requirements. Motivated by the positive validation results of surface densified manual transmission gears which are also applicable for dedicated hybrid transmissions (DHTs) like e-DCTs, GKN engineers have been looking for a more challenging application for PM gears within those areas.
Xspect Solutions Provides Wenzel Bridge-Type CMM Equipped with OpenDMIS Software for Basic Gear Measuring Capability with CMM Flexibility.
Molded plastic gears have very little in common with machined gears other than the fact that both use the involute for conjugate action.
Transmission error (TE) is recognized as one of the most important causes of gear acoustic emissions...
Plastic gears and transmissions require a different design approach than metal transmissions. Different tools are available to the plastic transmission designer for optimizing his geared product, and different requirements exist for inspection and testing. This paper will present some of the new technology available to the plastic gear user, including design, mold construction, inspection, and testing of plastic gears and transmissions.
Gear-loaded tooth contact analysis is an important tool for the design and analysis of gear performance within transmission and driveline systems. Methods for the calculation of tooth contact conditions have been discussed in the literature for many years. It's possible the method you've been using is underestimating transmission error in helical gears. Here's why.
Remembering Panhard and Levassor, the company that invented the first manual transmission.
The oil-off (also known as loss-of-lubrication or oil-out) performance evaluation of gears is of significant interest to the Department of Defense and various rotorcraft manufacturers, so that the aircraft can safely land in an accidental loss-of-lubricant situation. However, unlike typical gear failure modes such as pitting or bending fatigue where early detection is possible, gear failure in an oil-off situation is very rapid and likely catastrophic. Failures rapidly result in the loss of torque transmission and the inability to control the aircraft.
The authors use data analysis to determine which tolerances have the greatest effect on transmission error, enabling them to make adjustments and reduce production costs.
In this paper the effects of thermally induced geometry distortions on load distribution and transmission error have been analyzed.
This article presents an analysis of asymmetric tooth gears considering the effective contact ratio that is also affected by bending and contact tooth deflections. The goal is to find an optimal solution for high performance gear drives, which would combine high load capacity and efficiency, as well as low transmission error (which affects gear noise and vibration).
There is a great need for future powertrains in automotive and industrial applications to improve upon their efficiency and power density while reducing their dynamic vibration and noise initiation. It is accepted that planetary gear transmissions have several advantages in comparison to conventional transmissions, such as a high power density due to the power division using several planet gears. This paper presents planetary gear transmissions, optimized in terms of efficiency, weight and volume.
Oil-out conditions, or conditions in which an aircraft is operating without any oil in its gearbox or transmission, are devastating for an aircraft's hardware. Even the sturdiest gears usually can't last 30 minutes under such conditions before they catastrophically fail, and the whole system usually follows shortly after. That doesn't leave pilots with a whole lot of time to find a suitable location to land in the case of an oil-out emergency.
Gear noise can be a source of intense annoyance. It is often the primary source of annoyance even when it is not the loudest noise component. This is because of the way it is perceived. Gear noise is a collection of pure tones which the human ear can detect even when they are 10dB lower than the overall noise level. Another reason for our sensitivity to transmission noise is that we associate it with impending mechanical failure.
This paper will demonstrate that, unlike commonly used low-contact-ratio spur gears, high-contact-ratio spur gears can provide higher power-to-weight ratio, and can also achieve smoother running with lower transmission error (TE) variations.
This paper discusses the influence of tip relief, root relief, load modification, end relief and their combinations on gear stresses and transmission errors due to shaft deflections.
VMT Technologies designs positively engaged, infinitely variable transmission.
The complete Industry News section from the October 2013 issue of Gear Technology.
Bradley University and Winzeler Gear collaborate on the design and development of an urban light vehicle.
Over the last 15 years, there has been significant growth in the number of transmission types as well as their complexity: manual, conventional automatic, dual clutch, automated manual, continuously variable, split power and pure EV transmissions.
Big gears and wind turbines go together like bees and honey, peas and carrots, bread and butter andâ€”well, you get the idea. Wind isnâ€™t just big right now, itâ€™s huge. The wind industry means tremendous things for the energy dependent world we live in and especially big things for gear manufacturers and other beleaguered American industries.
For metal replacement with powder metal (PM) of an automotive transmission, PM gear design differs from its wrought counterpart. Indeed, complete reverse-engineering and re-design is required so to better understand and document the performance parameters of solid-steel vs. PM gears. Presented here is a re-design (re-building a 6-speed manual transmission for an Opel Insignia 4-cylinder, turbocharged 2-liter engine delivering 220 hp/320 N-m) showing that substituting a different microgeometry of the PM gear teeth -- coupled with lower Youngâ€™s modulus -- theoretically enhances performance when compared to the solid-steel design.
Top Secret Code Name: Ginger Mission: Design, prototype and test a transmission for a new device. The transmission must be compact and efficient. It should have almost no backlash, and it must be able to operate in both forward and reverse. Most importantly, the transmission must be quiet. In fact, it shouldn't sound like a transmission at all. It should blend in with the environment and sound like music or the wind. This mission, should you choose to accept it, is top secret. Not even your employees can know what you're working on...
Like many of you in the gear industry, weâ€™ve been working extremely hard over the past few months getting ready for Gear Expo 2013, which takes place September 17-19 in Indianapolis.
The objective of this paper is to demonstrate that transmission gears of rotary-wing aircraft, which are typically scrapped due to minor foreign object damage (FOD) and grey staining, can be repaired and re-used with signifi cant cost avoidance. The isotropic superfinishing (ISF) process is used to repair the gear by removing surface damage. It has been demonstrated in this project that this surface damage can be removed while maintaining OEM specifications on gear size, geometry and metallurgy. Further, scrap CH-46 mix box spur pinions, repaired by the ISF process, were subjected to gear tooth strength and durability testing, and their performance compared with or exceeded that of new spur pinions procured from an approved Navy vendor. This clearly demonstrates the feasibility of the repair and re-use of precision transmission gears.
Attempts to eliminate mechanical drive trains in automobiles and trucks have had limited success because of cost, weight, dynamic characteristic, and efficiency of the alternative components.
This presentation is an expansion of a previous study (Ref.1) by the authors on lapping effects on surface finish and transmission errors. It documents the effects of the superfinishing process on hypoid gears, surface finish and transmission errors.
Publisher Michael Goldstein describes the success of Gear Technology's new e-mail newsletter programs.
Joe Arvin comments on his recent trip to Scandinavia and how U.S. defense dollars are being spent overseas. J.D. Smith responds to an article on gear noise from the previous issue.
Chairman Todd Praneis of Cotta Transmission describes the activities of AGMA's Enclosed Drives technical committee.
When designing hardened and ground spur gears to operate with minimum noise, what are the parameters to be considered? should tip and/or root relief be applied to both wheel and pinion or only to one member? When pinions are enlarged and he wheel reduced, should tip relief be applied? What are the effects on strength, wear and noise? For given ratios with enlarged pinions and reduced wheels, how can the gear set sized be checked or adjusted to ensure that the best combination has been achieved?
As the Indianapolis 500 begins its second hundred years, it is a good opportunity to recall the guy who put the gearbox "up front."
The Past, Present and Future of Vehicle Electrification
Let's face it. The Internet is still, to many of us, exciting, confusing, terrifying and frustrating by turns. The buzzwords change so fast that even the most high tech companies have a hard time keeping up. Cyberspace. Firewall, Java. E-commerce. The list goes on.
It's more important than ever to understand the full system your individual components are going into. Here's the latest in how software developers are helping you do that.
Anyone involved in the design, manufacture and use of gears is concerned with three general characteristics relative to their application: noise, accuracy, and strength or surface durability. In the article, we will be dealing with probably the most aggravating of the group, gear noise.
CTI Symposium Presents Latest Automotive Transmission Developments and Applications.
Gear noise is among the issues of greatest concern in today's modern gearboxes. Significant research has resulted in the application of enhancements in all phases of gear manufacturing, and the work is ongoing. With the introduction of Electric Vehicles (EV), research and development in this area has surged in recent years. Most importantly, powerful new noise analysis solutions are fast becoming available.
Presumably, everyone who would be interested in this subject is already somewhat familiar with testing of gears by traditional means. Three types of gear inspection are in common use: 1) measurement of gear elements and relationships, 2) tooth contact pattern checks and 3) rolling composite checks. Single Flank testing falls into this last category, as does the more familiar Double Flank test.
The paper is not the proof of a discovery, but it is the description of a method: the optimization of the microgeometry for cylindrical gears. The method has been applied and described on some transmissions with helical gears and compound epicyclic, used on different hybrid vehicles. However, the method is also valid for industrial gearboxes.
It is becoming increasingly apparent that material properties can and will play a greater role than before in addressing the challenges most transmission manufacturers are facing today. Making use of materials' intrinsic fatigue properties provides a new design tool to support the market changes taking place.
Due to increasing requirements regarding the vibrational behavior of automotive transmissions, it is necessary to develop reliable methods for noise evaluation and design optimization. Continuous research led to the development of an elaborate method for gear noise evaluation. The presented methodology enables the gear engineer to optimize the microgeometry with respect to robust manufacturing.
The powder metal (P/M) process is making inroads in automotive transmission applications due to substantially lower costs of P/M-steel components for high-volume production, as compared to wrought or forged steel parts. Although P/M gears are increasingly used in powered hand tools, gear pumps and as accessory components in automotive transmissions, P/M-steel gears are currently in limited use in vehicle transmission applications. The primary objective of this project was to develop high-strength P/M-steel gears with bending fatigue, impact resistance and pitting fatigue performance equivalent to current wrought steel gears.
Except for higher-end gear applications found in automotive and aerospace transmissions, for example, high-performance, sintered-steel gears match wrought-steel gears in strength and geometrical quality. The enhanced P/M performance is due largely to advances in powder metallurgy over last two decades, such as selective surface densification, new materials and lubricants for high density and warm-die pressing. This paper is a review of the results of a decade of research and development of high- performance, sintered-steel gear prototypes.
This paper presents how low pressure carburizing and high pressure gas quenching processes are successfully applied on internal ring gears for a six-speed automatic transmission. The specific challenge in the heat treat process was to reduce distortion in such a way that subsequent machining operations are entirely eliminated.
Gear pitting is one of the primary failure modes of automotive transmission gear sets. Over the past years, many alternatives have been intended to improve their gear surface durability. However, due to the nature of new process development, it takes a length of time and joint efforts between the development team and suppliers to investigate and verify each new approach.
Bevel gears have been the standard for several decades in situations where power transmission has to occur between shafts mounted at a given angle. Now a new approach has been developed that challenges the bevel gear's de facto monopoly in such applications. The concept is based on the principle of the crown gear; i.e., a cylindrical pinion mates with a face gear. Crown Gear B.V. in Enschede, Holland, is the developer of these specialty gear teeth, which are marketed under the trade name Cylkro.
Planetary gear transmissions are compact, high-power speed reducers that use parallel load paths. The range of possible reduction ratios is bounded from below and above by limits on the relative size of the planet gears. For a single-plane transmission, the planet gear has no size of the sun and ring. Which ratio is best for a planetary reduction can be resolved by studying a series of optimal designs. In this series, each design is obtained by maximizing the service life for a planetary transmission with a fixed size, gear ratio, input speed, power and materials. The planetary gear reduction service life is modeled as a function of the two-parameter Weibull distributed service lives of the bearings and gears in the reduction. Planet bearing life strongly influences the optimal reduction lives, which point to an optimal planetary reduction ratio in the neighborhood of four to five.
Often, the required hardness qualities of parts manufactured from steel can only be obtained through suitable heat treatment. In transmission manufacturing, the case hardening process is commonly used to produce parts with a hard and wear-resistant surface and an adequate toughness in the core. A tremendous potential for rationalization, which is only partially used, becomes available if the treatment time of the case hardening process is reduced. Low pressure carburizing (LPC) offers a reduction of treatment time in comparison to conventional gas carburizing because of the high carbon mass flow inherent to the process (Ref. 1).
How important is the right choice of coupling in determining successful machine design? Consider the following example. A transmission of appropriate size was needed to transfer the speed of the engine driver to that of the driven generator. The transmission was properly selected and sized to endure the rated power requirements indefinitely, but after only a short time in operation, it failed anyway. What happened? The culprit in the case was a coupling. It provided the necessary power and protection against misalignment but it lacked the ability to isolate the gears from the torque peaks of the diesel engine.
A transverse-torsional dynamic model of a spur gear pair is employed to investigate the influence of gear tooth indexing errors on the dynamic response. With measured long-period quasi-static transmission error time traces as the primary excitation, the model predicts frequency-domain dynamic mesh force and dynamic transmission error spectra. The dynamic responses due to both deterministic and random tooth indexing errors are predicted.
The honing of gears - by definition - facilitates ease of operation, low noise and smoother performance in a transmission. Honing also contributes to reduced friction in the powertrain. Both the intense cutting (roughing process) as well as the functionally fine- finishing of transmission gears can be performed in one setup, on one machine.
Modern gear design is generally based on standard tools. This makes gear design quite simple (almost like selecting fasteners), economical, and available for everyone, reducing tooling expenses and inventory. At the same time, it is well known that universal standard tools provide gears with less than optimum performance and - in some cases - do not allow for finding acceptable gear solutions. Application specifies, including low noise and vibration, high density of power transmission (lighter weight, smaller size) and others, require gears with nonstandard parameters. That's why, for example, aviation gear transmissions use tool profiles with custom proportions, such as pressure angle, addendum, and whole depth. The following considerations make application of nonstandard gears suitable and cost-efficient:
With the ongoing push towards electric vehicles (EVs), there is likely to be increasing focus on the noise impact of the gearing required for the transmission of power from the (high-speed) electric motor to the road. Understanding automotive noise, vibration and harshness (NVH) and methodologies for total in-vehicle noise presupposes relatively large, internal combustion (IC) contributions, compared to gear noise. Further, it may be advantageous to run the electric motors at significantly higher rotational speed than conventional automotive IC engines, sending geartrains into yet higher speed ranges. Thus the move to EV or hybrid electric vehicles (HEVs) places greater or different demands on geartrain noise. This work combines both a traditional NVH approach (in-vehicle and rig noise, waterfall plots, Campbell diagrams and Fourier analysis) - with highly detailed transmission error measurement and simulation of the complete drivetrain - to fully understand noise sources within an EV hub drive. A detailed methodology is presented, combining both a full series of tests and advanced simulation to troubleshoot and optimize an EV hub drive for noise reduction.
Two-shaft planetary gear drives are power-branching transmissions, which lead the power from input to output shaft on several parallel ways. A part of the power is transferred loss-free as clutch power. That results in high efficiency and high power density. Those advantages can be used optimally only if an even distribution of load on the individual branches of power is ensured. Static over-constraint, manufacturing deviations and the internal dynamics of those transmission gears obstruct the load balance. With the help of complex simulation programs, it is possible today to predict the dynamic behavior of such gears. The results of those investigations consolidate the approximation equations for the calculation of the load factors...
An analytical method is presented to predict the shifts of the contact ellipses on spiral bevel gear teeth under load. The contact ellipse shift is the motion of the point to its location under load. The shifts are due to the elastic motions of the gear and pinion supporting shafts and bearings. The calculations include the elastic deflections of the gear shafts and the deflections of the four shaft bearings. The method assumes that the surface curvature of each tooth is constant near the unloaded pitch point. Results from these calculations will help designers reduce transmission weight without seriously reducing transmission performance.
The efficient and reliable transmission of mechanical power continues, as always, to be a central area of concern and study in mechanical engineering. The transmission of power involves the interaction of forces which are transmitted by specially developed components. These components must, in turn, withstand the complex and powerful stresses developed by the forces involved. Gear teeth transmit loads through a complex process of positive sliding, rolling and negative sliding of the contacting surfaces. This contact is responsible for both the development of bending stresses at the root of the gear teeth and the contact stresses a the contacting flanks.
Stringent NVH requirements, higher loads and the trend towards miniaturization to save weight and space are forcing transmission gear designers to increasingly tighten the surface finish, bore size and bore-to-face perpendicularity tolerances on the bores of transmission gears.
Examples from gears in wind turbine, automotive and industrial applications.
Surface-hardened, sintered powder metal gears are increasingly used in power transmissions to reduce the cost of gear production. One important problem is how to design with surface durability, given the porous nature of sintered gears. Many articles have been written about mechanical characteristics, such as tensile and bending strength, of sintered materials, and it is well-known that the pores existing on and below their surfaces affect their characteristics (Refs. 1-3). Power transmission gears are frequently employed under conditions of high speed and high load, and tooth surfaces are in contact with each other under a sliding-rolling contact condition. Therefore it is necessary to consider not only their mechanical, but also their tribological characteristics when designing sintered gears for surface durability.
Zerol bevel gears are the special case of spiral bevel gears with a spiral angle of 0°. They are manufactured in a single-indexing face milling process with large cutter diameters, an extra deep tooth profile and tapered tooth depth.
When, in 1980, OSU professor Donald R. Houser created the Gear and Power Transmission Research Laboratory - then known as the Gear Dynamics and Gear and Power Transmission Laboratory (GearLab) - he did so with the seed money provided by just three companies. Thirty-three years out, the lab has continued to grow, impress andâ€”most importantly - succeed; it now boasts a roster of some 50 sponsoring companies and government agencies.
â€śHighway vehicles release about 1.7 billion tons of greenhouse gases (GHGs) into the atmosphere each year â€” mostly in the form of carbon dioxide (CO2) â€” contributing to global climate change. The CO2 emissions of a car are directly proportional to the quantity of fuel consumed by an engine. In 2013, U.S. greenhouse gas emissions from transportation were second only to the electricity sector â€” an increase of about 16% since 1990.â€ť (EPA.GOV).
This article is part five of an eight-part series on the tribology aspects of angular gear drives. Each article will be presented first and exclusively by Gear Technology, but the entire series will be included in Dr. Stadtfeldâ€™s upcoming book on the subject, which is scheduled for release in 2011.
This article is part four of an eight-part series on the tribology aspects of angular gear drives. Each article will be presented first and exclusively by Gear Technology, but the entire series will be included in Dr. Stadtfeldâ€™s upcoming book on the subject, which is scheduled for release in 2011.
Hypoid gears are the paragon of gearing. To establish line contact between the pitches in hypoid gears, the kinematically correct pitch surfaces have to be determined based on the axoids. In cylindrical and bevel gears, the axoids are identical to the pitch surfaces and their diameter or cone angle can be calculated simply by using the knowledge about number of teeth and module or ratio and shaft angle. In hypoid gears, a rather complex approach is required to find the location of the teethâ€”even before any information about flank form can be considered. This article is part seven of an eight-part series on the tribology aspects of angular gear drives.
In our association, we might be suppliers, partners, customers or competitors, but in the end, we are one industry â€” and now is the time when we need to come together and move the industry forward.â€ť
Transmission errors, axial shuttling forces and friction result in bearing forces that serve as the major excitations of gear noise. This paper will use these factors as well as gear stresses and tribological factors to assist in obtaining optimal gear designs.
Plastic gears are serious alternatives to traditional metal gears in a wide variety of applications. The use of plastic gears has expanded from low-power, precision motion transmission into more demanding power transmission applications. As designers push the limits of acceptable plastic gear applications, more is learned about the behavior of plastics in gearing and how to take advantage of their unique characteristics.
"General Explanations on Theoretical Bevel Gear Analysis" is part 1 of an eight-part series from Gleason's Dr. Hermann Stadtfeld.
Romax Technology is automating the design iteration process to allow companies to be faster to market with the highest quality, most robust gear products.
A common design goal for gears in helicopter or turboprop power transmission is reduced weight. To help meet this goal, some gear designs use thin rims. Rims that are too thin, however, may lead to bending fatigue problems and cracks. The most common methods of gear design and analysis are based on standards published by the American Gear Manufacturers Association. Included in the standards are rating formulas for gear tooth bending to prevent crack initiation (Ref. 1). These standards can include the effect of rim thickness on tooth bending fatigue (Ref 2.). The standards, however, do not indicate the crack propagation path or the remaining life once a crack has started. Fracture mechanics has developed into a useful discipline for predicting strength and life of cracked structures.
The heat treatment processing of powder metal (PM) materials like Astaloy requires four steps -- de-waxing, HT sintering, carburizing and surface hardening -- which are usually achieved in dedicated, atmospheric furnaces for sintering and heat treat, respectively, leading to intermediate handling operations and repeated heating and cooling cycles. This paper presents the concept of the multi-purpose batch vacuum furnace, one that is able to realize all of these steps in one unique cycle. The multiple benefits brought by this technology are summarized here, the main goal being to use this technology to manufacture high-load transmission gears in PM materials.
In todayâ€™s globalized manufacturing, all industrial products having dimensional constraints must undergo conformity specifications assessments on a regular basis. Consequently, (standardization) associated with GD&T (geometrical dimensioning and tolerancing) should be un-ambiguous and based on common, accepted rules. Of course gears - and their mechanical assemblies - are special items, widely present in industrial applications where energy conversion and power transmission are involved.
Several articles have appeared in this publication in recent years dealing with the principles and ways in which the inspection of gears can be carried out, but these have dealt chiefly with spur, helical and bevel gearing, whereas worm gearing, while sharing certain common features, also requires an emphasis in certain areas that cause it to stand apart. For example, while worm gears transmit motion between nonparallel shafts, as do bevel and hypoid gears, they usually incorporate much higher ratios and are used in applications for which bevel would not be considered, including drives for rotary and indexing tables in machine tools, where close tolerance of positioning and backlash elimination are critical, and in situations where accuracy of pitch and profile are necessary for uniform transmission at speed, such as elevators, turbine governor drives and speed increasers, where worm gears can operate at up to 24,000 rpm.
It is widely recognized that the reduction of CO2 requires consistent light-weight design of the entire vehicle. Likewise, the trend towards electric cars requires light-weight design to compensate for the additional weight of battery systems. The need for weight reduction is also present regarding vehicle transmissions. Besides the design of the gearbox housing, rotating masses such as gear wheels and shafts have a significant impact on fuel consumption. The current technology shows little potential of gear weight reduction due to the trade-off between mass optimization and the manufacturing process. Gears are usually forged followed or not by teeth cutting operation.
A gear design optimization approach applied to reduce tooth contact temperature and noise excitation of a high-speed spur gear pair running without lubricant. Optimum gear design search was done using the Run Many Cases software program. Thirty-one of over 480,000 possible gear designs were considered, based on low contact temperature and low transmission error. The best gear design was selected considering its manufacturability.
Would you like to be able to see the condition of the gears in your transmissions without having to open the box and physically examine them? There is a way, and not too many people know about it. It's called Wear Particle Analysis, or ferrography, and it is just starting to get noticed.
The effort described in this paper addresses a desire in the gear industry to increase power densities and reduce costs of geared transmissions. To achieve these objectives, new materials and manufacturing processes, utilized in the fabrication of gears, and being evaluated. In this effort, the first priority is to compare the performance of gears fabricated using current materials and processes. However, once that priority is satisfied, it rapidly transforms to requiring accurate design data to utilize these novel materials and processes. This paper describes the effort to address one aspect of this design data requirement.
Designers are constantly searching for ways to reduce rotocraft drive system weight. Reduced weight can increase the payload, performance, or power density of current and future systems. One example of helicopter transmission weight reduction was initiated as part of the United States Army Advanced Rotocraft Transmission program. This example used a split-torque, face-gear configuration concept (Ref. 1). compared to a conventional design with spiral-bevel gears, the split-torque, face-gear design showed substantial weight savings benefits. Also, the use of face gears allows a wide-range of possible configurations with technical and economic benefits (Ref. 2).
Air compressors are a good example of industrial machinery with components that rotate at very high speeds, up to 80,000 rpm. They are subject to very high rotational forces and often variable loads. Strong, high-precision gears for the power transmission trains that drive the impellers are critical components of machinery operating under such conditions.
Plastics as gear materials represent an interesting development for gearing because they offer high strength-to-weight ratios, ease of manufacture and excellent tribological properties (Refs. 1-7). In particular, there is a sound prospect that plastic gears can be applied for power transmission of up to 10 kW (Ref. 6).
Traditionally, high-quality gears are cut to shape from forged blanks. Great accuracy can be obtained through shaving and grinding of tooth forms, enhancing the power capacity, life and quietness of geared power transmissions. In the 1950s, a process was developed for forging gears with teeth that requires little or no metal to be removed to achieve final geometry. The initial process development was undertaken in Germany for the manufacture of bevel gears for automobile differentials and was stimulated by the lack of available gear cutting equipment at that time. Later attention has turned to the forging of spur and helical gears, which are more difficult to form due to the radial disposition of their teeth compared with bevel gears. The main driver of these developments, in common with most component manufacturing, is cost. Forming gears rather than cutting them results in increased yield from raw material and also can increase productivity. Forging gears is therefore of greater advantage for large batch quantities, such as required by the automotive industry.
This article also appears as Chapter 1 in the Gleason Corporation publication "Advanced Bevel Gear Technology." Gearing Principles in Cylindrical and Straight Bevel Gears The purpose of gears is to transmit motion and torque from one shaft to another. That transmission normally has to occur with a constant ratio, the lowest possible disturbances and the highest possible efficiency. Tooth profile, length and shape are derived from those requirements.
The need for improved power transmissions that use gears and gearboxes with smaller overall dimensions and with lower noise generation has left manufacturing engineers searching for different methods of gear processing. This search has led to the requirement of hardened gears.
The Gear Industry â€” and companies from the entire power transmission supply chain â€” will gather in-person at Motion + Power Technology Expo 2021
Evaluation of the bending fatigue performance (stress to life relationship) of different gear materials subject to various manufacturing processes and why subsequent post processing treatments are of significance to gear and transmission designers.
One way to implement the growing performance requirements for transmissions is by optimizing the surface finish of the gearing. In addition to increasing the flank load capacity and the transmittable torque, this also allows for improvements in efficiency. On Oerlikon bevel gear grinding machines from Klingelnberg, fine grinding can be implemented efficiently in bevel gear production - even in an industrial serial process.
Physical effects causing transmission noise.
Physical effects that cause transmission noise.
Higher order flank form optimizations and motion transmission characteristic.
Gleason Combi Honing system meets eDrive transmission standards.
How the increasing demands on power transmission and reduction in mass of modern gearboxes lead to gear designs that are close to their load-carrying capacity limits.
Nowadays, the progress in polymer materials and injection molding processing has enabled a drastic expansion of plastic gear applications. They are used not only for lightly loaded motion transmissions, but also in moderately loaded power drives in automotive, agriculture, medical, robotics, and many other industries.
FVA software offers simulation and calculation of transmission systems.
Polymer gears find increasing applications in the automotive industry, office machines, food machinery, and home appliances. The main reason for this success is their low cost. Their low weight, quietness of operation, and meshing without lubricant are also interesting. However, they have poor heat resistance and are limited to rotational transmission. In order to improve the gears' behavior, glass fiber is added
In many gear transmissions, tooth load on one flank is significantly higher and is applied for longer periods of time than on the opposite one; an asymmetric tooth shape should reflect this functional difference. The advantages of these gears allow us to improve the performance of the primary drive tooth flanks at the expense of the opposite coast flanks, which are unloaded or lightly loaded during a relatively short work period by drive flank contact and bending stress reduction. This article is about the microgeometry optimization of the spur asymmetric gearsâ€™ tooth flank profile based on the tooth bending and contact deflections.
NVH â€” noise, vibration and harshness â€” is a key issue in the design and development of modern transmission and driveline systems.
Thanks to material development and additive manufacturing opportunities, itâ€™s important for the gear and power transmission industries to monitor the trends, technologies and future forecasts in the powder metal market.
New GRSL technology adds value to high-volume transmission gear inspection by combining non-contact laser inspection with tried-and-true composite roll testing.
Fraunhofer CMI focuses on new U.S. gear and transmission technologies group, plus other news from around the industry.
Gear designers face constant pressure to increase power density in their drivetrains. In the automotive industry, for example, typical engine torque has increased significantly over the last several decades. Meanwhile, the demands for greater fuel efficiency mean designers must accommodate these increased loads in a smaller, more lightweight package than ever before. In addition, electric and hybrid vehicles will feature fewer gears, with fewer transmission speeds, running at higher rpms, meaning the gears in those systems will have to endure life cycles far beyond what is typical with internal combustion engines.
First, the facts: powder metallurgy is a cost-effective method of forming precision net-shape metal components that allows for more efficiently designed products. It saves valuable raw materials through recycling and the elimination of costly secondary-machining. PM competes with wrought steel gears as the technology continues to advance. You'll find PM components in everything from automobile transmissions to aircraft turbine engines, surgical equipment and power tools.
Broaching is a machining technique commonly used to cut gear teeth or cam profiles for the high volume manufacture of power transmission parts used in vehicles (Refs. 1â€“2). This article shows how the right gear blank material can make all the difference if you want to get more parts out of each tool.
Detection of impending gear tooth failure is of interest to every entity that utilizes geared transmissions. However, it is of particular significance at the Gear Research Institute (GRI), where sponsored efforts are conducted to establish gear material endurance limits, utilizing gear fatigue tests. Consequently, knowing when a gear is about to fail in each and every test, in a consistent manner, is essential for producing reliable and useful data for the gear industry.
I have outsourced gear macrogeometry due to lack of resources. Now I received the output from them and one of the gears is with â€”0.8Ă— module correction factor for m = 1.8 mm gear. Since bending root stress and specific slide is at par with specification, but negative correction factor â€”0.8Ă— module â€” is quite high â€” how will it influence NVH behavior/transmission error? SAP and TIF are very close to 0.05 mm; how will that influence the manufacturing/cost?
NASA is now 3-D-printing spare parts up at the ISS (International Space Station). And in zero-gravity environments. And some of these parts are small gears and actuators, for starters. Every indication is that the list of power transmission-type parts to be converted will soon grow.
This paper describes the investigation of a steel-and-plastic gear transmission and presents a new hypothesis on the governing mechanism in the wear of plastic gears.
At the recently held Motion+Power Technology Expo, we had the opportunity to sit down with a number of exhibitors to learn more about the latest in technology for the mechanical power transmission industry â€“ including gear manufacturing machine tools, workholding, inspection equipment and much more.
With the aim of reducing the operating noise and vibration of planetary gear sets used in automatic transmissions, a meshing phase difference was applied to the planet gears that mesh with the sun and ring gears.
Mechanical efficiency is an important index of gearing, especially for epicyclic gearing. Because of its compact size, light weight, the capability of a high speed ratio, and the ability to provide differential action, epicyclic gearing is very versatile, and its use is increasing. However, attention should be paid to efficiency not only to save energy, but sometimes also to make the transmission run smoothly or to avoid a self-locking condition.
Increasingly gear designers and product engineers are capitalizing on the economic advantages of powder metallurgy (P/M) for new and existing gear applications. Powder metal gears are found in automobiles, outdoor power equipment transmissions and office machinery applications as well as power hand tools, appliances and medial components.
A very direct and effective way of increasing power transmission efficiency is a changeover from mineral-oil-based lubricants to synthetic lubricants.
In this paper a new method for the introduction of optimal modifications into gear tooth surfaces - based on the optimal corrections of the profile and diameter of the head cutter, and optimal variation of machine tool settings for pinion and gear finishingâ€”is presented. The goal of these tooth modifications is the achievement of a more favorable load distribution and reduced transmission error. The method is applied to face milled and face hobbed hypoid gears.
Dutch design and Swiss ingenuity cause transmission breakthrough. Updated examples of Cylkro face gears in action.
In co-operation with Voith, a major transmission manufacturer in Germany, Heller has developed a process that significantly enhances the productivity of pre-milling and gear milling operations performed on a single 5-axis machining center.
As the automotive industry continues to reinvent itself, new transmission technologies are at the forefront of this effort, and there is a whirlwind of new developments being detailed at the German Car Training Instituteâ€™s Automotive Transmissions and Drive Trains Symposium North America.
Studies to evaluate low-noise Formate spiral bevel gears were performed. Experimental tests were conducted on a helicopter transmission test stand...
Traditionally, a worm or a multi-stage gear box has been used when a large speed ratio is required. However, such boxes will become obsolete as size and efficiency become increasingly important considerations for a modern transmission. The single-enveloped worm gear has a maximum speed ratio of only 40 to 60. Its efficiency is only 30 to 60 per cent. The necessity of using bronze for the worm gear and grinding nitoalloy steel for the worm drives up material and manufacturing costs.
MASTA 4.5.1 models complete transmissions and includes 3-D stress analysis.
Above all, a gear is not just a mechanical transmission, but is developed to a system fulfilling multiple demands, such as clutch integration, selectable output speeds, and controls of highest electronic standards. This paper shows the basics for high-speed gear design and a selection of numerous applications in detailed design and operational needs.
Gear engineers have long recognized the importance of considering system factors when analyzing a single pair of gears in mesh. These factors include important considerations such as load sharing in multi-mesh geartrains and bearing clearances, in addition to the effects of flexible components such as housings, gear blanks, shafts and carriers for planetary geartrains. However, in recent years, transmission systems have become increasingly complexâ€”with higher numbers of gears and componentsâ€”while the quality requirements and expectations in terms of durability, gear whine, rattle and efficiency have increased accordingly.
This article was originally published 20 years ago, in Gear Technologyâ€™s first issue. It describes a method of evaluating the smoothness, or lack of smoothness, of gear motion. This lack of smoothness of motion, known as â€śtransmission error,â€ť is responsible for excitation of gear noise and problems of gear accuracy and sometimes has a relationship to gear failure.
Glancing back now, The Falk Corp. looks to have had a straight path toward power transmission when it opened in 1892.
Calculation of gear tooth flexibility is of interest for at least two reasons: (a) It controls, at least in part, the vibratory properties of a transmission system hence, fatigue resistance and noise: (b) it controls load sharing in multiple tooth contact.
The main theme of this article is high-capacity, high-speed load gears in a power transmission range between 35 MW and 100 MW for generators and turbo-compressors driven by gas or steam turbines.
In most transmission systems, one of the main power loss sources is the loaded gear mesh. In this article, the influences of gear geometry parameters on gear efficiency, load capacity, and excitation are shown.
Transmission of power between nonparallel shafts is inherently more difficult than transmission between parallel shafts, but is justified when it saves space and results in more compact, more balanced designs. Where axial space is limited compared to radial space, angular drives are preferred despite their higher initial cost. For this reason, angular gear motors and worm gear drives are used extensively in preference to parallel shaft drives, particularly where couplings, brakes, and adjustable mountings add to the axial space problem of parallel shaft speed reducers.
Spiral-bevel gears, found in many machine tools, automobile rear-axle drives, and helicopter transmissions, are important elements for transmitting power.
There are different types of spiral bevel gears, based on the methods of generation of gear-tooth surfaces. A few notable ones are the Gleason's gearing, the Klingelnberg's Palloid System, and the Klingelnberg's and Oerlikon's Cyclo Palliod System. The design of each type of spiral bevel gear depends on the method of generation used. It is based on specified and detailed directions which have been worked out by the mentioned companies. However, there are some general aspects, such as the concepts of pitch cones, generating gear, and conditions of force transmissions that are common for all types of spiral bevel gears.
Engineering design requires many different types of gears and splines. Although these components are rather expensive, subject to direct wear, and difficult to replace, transmissions with gears and splines are required for two very simple reasons: 1) Motors have an unfavorable (disadvantageous) relation of torque to number of revolutions. 2)Power is usually required to be transmitted along a shaft.
Precision gears play a vital role in today's economy. Through their application, automobile transmissions are more compact and efficient, ships sail faster, and diesel locomotives haul more freight. Today great emphasis is being placed upon the reduction of noise in all gear applications and, to be quiet, gears must be accurate.
In the 1960's and early 1970's, considerable work was done to identify the various modes of damage that ended the lives of rolling element bearings. A simple summary of all the damage modes that could lead to failure is given in Table 1. In bearing applications that have insufficient or improper lubricant, or have contaminants (water, solid particles) or poor sealing, failure, such as excessive wear or vibration or corrosion, may occur, rather than contact fatigue. Usually other components in the overall system besides bearings also suffer. Over the years, builders of transmissions, axles, and gear boxes that comprise such systems have understood the need to improve the operating environment within such units, so that some system life improvements have taken place.
The NASA Lewis Research Center investigated the effect of tooth profile on the acoustic behavior of spur gears through experimental techniques. The tests were conducted by Cleveland State University (CSU) in NASA Lewis' spur gear testing apparatus. Acoustic intensity (AI) measurements of the apparatus were obtained using a Robotic Acoustic Intensity Measurement System (RAIMS). This system was developed by CSU for NASA to evaluate the usefulness of a highly automated acoustic intensity measurement tool in the reverberant environment of gear transmission test cells.
Runout is a troublemaker! Good shop practice for the manufacture or inspection of gears requires the control of runout. Runout is a characteristic of gear quality that results in an effective center distance variation. As long as the runout doesn't cause loss of backlash, it won't hurt the function of the gear, which is to transmit smooth motion under load from one shaft to another. However, runout does result in accumulated pitch variation, and this causes non-uniform motion, which does affect the function of the gears. Runout is a radial phenomenon, while accumulated pitch variation is a tangential characteristic that causes transmission error. Gears function tangentially. It is also possible to have a gear with accumulated pitch variation, but little or no runout.
A universal gear is one generated by a common rack on a cylindrical, conical, or planar surface, and whose teeth can be oriented parallel or skewed, centered, or offset, with respect to its axes. Mating gear axes can be parallel or crossed, non-intersecting or intersecting, skewed or parallel, and can have any angular orientation (See Fig.1) The taper gear is a universal gear. It provides unique geometric properties and a range of applications unmatched by any other motion transmission element. (See Fig.2) The taper gear can be produced by any rack-type tool generator or hobbing machine which has a means of tilting the cutter or work axis and/or coordinating simultaneous traverse and infeed motions.
Question: In the January/February issue of your magazine, we came across the term "electronic gearbox." We have seen this term used elsewhere as well. We understand that this EGB eliminates the change gear in the transmission line, but not how exactly this is done. Could you explain in more detail?
This article presents an efficient and direct method for the synthesis of compound planetary differential gear trains for the generation of specified multiple speed ratios. It is a train-value method that utilizes the train values of the integrated train components of the systems to form design equations which are solved for the tooth numbers of the gears, the number of mating gear sets and the number of external contacts in the system. Application examples, including vehicle differential transmission units, rear-end differentials with unit and fractional speed ratios, multi-input functions generators and robot wrist joints are given.
This method of testing large gearboxes or, indeed, any power transmission element, had numerous advantages and offers the possibility of large savings in time, energy, and plant, if the overall situation is conducive to its use. This usually requires that several such units need to be tested, and that they can be conveniently connected to each to each other in such a way as to form a closed-loop drive train. No power sink is required, and the drive input system has only to make up power losses. The level of circulating power is controlled by the torque, which is applied statically during rotation, and the drive speed. Principles, advantage, and limitations are described, together with recent experiences in the only known large-scale usage of this technique in Australia.
In many gear transmissions, a tooth load on one flank is significantly higher and is applied for longer periods of time than for the opposite one; an asymmetric tooth shape reflects this functional difference. This paper describes an approach that rationalizes the degree of asymmetry (or asymmetry factor K) selection to meet a variety of operating conditions and requirements for custom gear drives.
Aircraft transmissions for helicopters, turboprops and geared turbofan aircraft require high reliability and provide several thousand hours of operation between overhauls. In addition, They should be lightweight and have very high efficiency to minimize operating costs for the aircraft.
In today's industrial marketplace, deburring and chamfering are no longer just a matter of cosmetics. The faster speeds at which transmissions run today demand that gear teeth mesh as smoothly and accurately as possible to prevent premature failure. The demand for quieter gears also requires tighter tolerances. New heat treating practices and other secondary gear operations have placed their own set of demands on manufacturers. Companies that can deburr or chamfer to these newer, more stringent specifications - and still keep costs in line - find themselves with a leg up on their competition.
Our research group has been engaged in the study of gear noise for some nine years and has succeeded in cutting the noise from an average level to some 81-83 dB to 76-78 dB by both experimental and theoretical research. Experimental research centered on the investigation into the relation between the gear error and noise. Theoretical research centered on the geometry and kinematics of the meshing process of gears with geometric error. A phenomenon called "out-of-bound meshing of gears" was discovered and mathematically proven, and an in-depth analysis of the change-over process from the meshing of one pair of teeth to the next is followed, which leads to the conclusion we are using to solve the gear noise problem. The authors also suggest some optimized profiles to ensure silent transmission, and a new definition of profile error is suggested.
Involute spur gears are very sensitive to gear misalignment. Misalignment will cause the shift of the bearing contact toward the edge of the gear tooth surfaces and transmission errors that increase gear noise. Many efforts have been made to improve the bearing contact of misaligned spur gears by crowning the pinion tooth surface. Wildhaber(1) had proposed various methods of crowning that can be achieved in the process of gear generation. Maag engineers have used crowning for making longitudinal corrections (Fig. 1a); modifying involute tooth profile uniformly across the face width (Fig. 1b); combining these two functions in Fig. 1c and performing topological modification (Fig. 1d) that can provide any deviation of the crowned tooth surface from a regular involute surface. (2)
This past fall, I had the opportunity to travel to Japan, Korea, Taiwan, and Singapore to witness first-hand the status of the power transmission and machine tool industries in these areas. Points of interest included equipment, material handling, computerization, wage and tax structures, inventory controls, and workforce attitude.
A major source of helicopter cabin noise (which has been measured at over 100 decibels sound pressure level) is the gearbox. Reduction of this noise is a NASA and U.S. Army goal. A requirement for the Army/NASA Advanced Rotorcraft Transmission project was a 10 dB noise reduction compared to current designs.
Why Transmissions in Electric Vehicles?
The popular perception today is that technological advancement is an engine running almost out of control. New products and processes are developing faster than we can keep up with them, as anyone who has had a new computer system crash into obsolescence practically before it's out of the box can tell you. But that's not the case everywhere. Transmission technology, for example.
In the June issue of our sister publication -- Power Transmission Engineering -- the Power Play feature (Destination Mars! -- pg. 64) was devoted to NASAâ€™s Mars-oriented LDSD (Low Density Supersonic Decelerator) project...
In February (2007), we launched a new magazine, Power Transmission Engineering (PTE). While most of you have probably already seen it...
Welcome to a new era of Gear Technology magazine! AGMA is proud to add Gear Technology, Gear Technology India, Power Transmission Engineering, the Michael Goldstein Gear Technology Library and supporting websites and circulation under its umbrella.
You may have noticed a few changes around here. Most notably, the face on this page isn't the one you're used to seeing here. As you've probably heard by now, Michael Goldstein, founder and Publisher since 1984, has stepped back from his day-to-day duties and transferred the operation of Gear Technology, Power Transmission Engineering and Gear Technology India to the American Gear Manufacturers Association.
"An industrial business with a very important growth potential for the next decade." That's the wind energy as described by Ivan Brems of gear manufacturer Hansen Transmissions International.
Tribology Aspects in Angular Transmission Systems, Part 2
Beveloids are helical gears with nonparallel shafts, with shaft angles generally between 5 degrees and 15 degrees. This is part VI in the Tribology Aspects in Angular Transmission Systems Series
Super-reduction hypoid gears (SRH) are bevel worm gears with certain differences regarding hypoid gears. If two axes are positioned in space and the task is to transmit motion and torque between them using some kind of gears with a ratio above 5 and even higher than 50, the following cases are commonly known. Tribology Aspects in Angular Transmission Systems, Part VIII.
The October 2011 issue of Gear Technology featured the article â€śLow-Distortion Heat Treatment of Transmission Components,â€ť which covered the combination of low-pressure carburizing and high pressure gas quenching in an automotive environment. Here, heat treating expert Dan Herring explains why oil quenching is an appropriate choice for many applications.
March 19-22, 1989. First International Applied Mechanical Systems Design Conference. Convention Center, Nashville, TN. April 25-27, 1989. ASME 5th Annual Power Transmission & Gearing Conference, Chicago, IL
It takes confidence to be the first to invest in new manufacturing technology. But the payback can be significant. That has been the experience at the Ford Motor Company's Transmission & Chassis Division plant at Indianapolis, IN, which boasts the world's first production application of dry hobbing.
News Items About transmission
1 Cotta Transmission Introduces New Creep Drive Gearbox (April 8, 2005)
Cotta's new creep drive transmission is designed to insert in the vehicle driveline after the main transmission. In the creep mode, t... Read News
2 Greaves Cotton Sells Power Transmission Units (December 12, 2003)
Greaves Cotton will sell off units involved in the manufacture and sale of power transmission products, which includes the plants at Pune... Read News
3 Toyota Advances IIoT Technology at Engine and Power Transmission Manufacturing Plant (July 20, 2020)
When the management at Toyota's engine and power transmission manufacturing plant in Walbrzych, Poland, looked to increase the availa... Read News
4 GM, BMW and DaimlerChrysler Announce $1 Billion Hybrid Transmission Development Program (April 15, 2006)
A research alliance consisting of GM, BMW and DaimlerChrysler plans to invest more than $1 billion to develop a new hybrid transmission t... Read News
5 Toyota Raises Transmission Production Capacity in Poland (April 14, 2006)
Toyota Motor Corp. announced that Toyota Motor Manufacturing Poland Sp.zo.o, a producer of transmissions and engines, will increase its ... Read News
6 Getrag Group and Getrag Ford Transmissions Combine Under Single Brand (April 6, 2006)
Fourteen individual companies in the Getrag Group and Getrag Ford Transmissions, all specializing in transmission systems, drivetrain com... Read News
7 Companies Join up for Electric Vehicle Transmission (November 29, 2011)
Three Swedish companies have brought together their know-how in transmission design, materials and manufacturing to produce a transmissio... Read News
8 Ticona Supports Hi-Lex Power Lift Gate Transmission (February 9, 2012)
An innovative transmission from Hi-Lex America Inc. continues to reliably and quietly open and close automotive lift gates thanks to desi... Read News
9 Allison Transmission Purchases Cell from C & B Machinery (April 10, 2012)
Allison Transmission, which manufactures commercial-duty automatic transmissions and hybrid propulsion systems for truck and off-road veh... Read News
10 Mahr Federal Builds Wireless Data Transmission into Calipers (February 13, 2014)
Mahr Federal has built wireless data transmission into its family of MarCal Digital Calipers, making them available for the same price as... Read News
11 Ford Invests $200 Million in Transmission Plant (March 22, 2007)
Ford Motor Co. announced a $200 million investment in the Sharonville, OH, transmission plant for a future high performance, fuel-efficie... Read News
12 Bison Gear, Armature Electric Partner for Power Transmission Distribution (April 13, 2005)
Bison Gear and Engineering announced the addition of Armature Electric Ltd. as the Bison power transmission distributor for western Canad... Read News
13 Mazda Hofu Plant Produces 25 Millionth Transmission (April 27, 2006)
Mazda Motor Corp. announced that cumulative production of vehicle transmissions in the Nakanoseki district of its Hofu plant in Yamaguch ... Read News
14 Eaton Cummins Endurant Transmission Becomes Standard Equipment for International Truck (January 17, 2020)
Eaton Cummins Automated Transmission Technologies has announced its Endurant 12-speed automated transmission – one of the lightest,... Read News
15 FVA-Workbench 5.5 Offers Detailed Transmission Calculation Results (May 1, 2019)
FVA-Workbench Version 5.5 of the simulation platform for transmission systems, released in May, accelerates development processes and pro... Read News
16 Ricardo Introduces New Approach to Transmission Design (April 1, 2020)
The 2020.1 Ricardo Software release marks the completion of the Ricardo transmission analysis solution, which provides a seamless toolcha... Read News
17 Gleason Offers Stadtfeld's Latest Book: eDrive Transmission Guide (July 2, 2020)
Today Gleason has four major concepts for high reduction transmissions which are ideal for electric vehicles and hybrid cars. Gleason has... Read News
18 Thornycroft Acquires Newage Transmissions (February 26, 2005)
Thornycraft Ltd., an automotive and off-highway equipment company, has acquired Newage Transmissions Ltd. Effective immediatly, Newage... Read News
19 Hansen Transmission Opens Chinese facility (February 18, 2005)
Hansen Transmissions has opened a facility in Shanghai, China, for the representation of its line of gear units, turbines and industrial ... Read News
20 Torque Transmission Introduces New Line of Right Angle Drives (April 2, 2006)
Torque Transmission introduced a line of right angle gear drives designed for various motion control applications where right angle motio... Read News
21 Honda Plans Expansion Transmission Facilities in Ohio, Georgia (April 16, 2004)
Honda announced a $100 million plan for construction of a plant in Tallapoosa, GA , and a plan for the expansion of their existing Ohio p... Read News
22 Bosch and Getrag Collaborate on Hybride Systems with Dual Clutch Transmissions (April 5, 2006)
GETRAG and Bosch signed a cooperative agreement covering the development and marketing of parallel hybrid systems in conjunction with dua... Read News
23 Genstar Acquires Colfax Power Transmission Group (April 16, 2004)
Colfax Power Transmission Group was recently acquired by Genstar Capital L.P., a private equity firm. In a related move, Colfax PT has me... Read News
24 Power Transmission Association Releases Purchasing Report (December 19, 2003)
The Power Transmission Distributors Association's (PTDA) latest report claims that U.S. and Canadian end users consider the product q... Read News
25 New Facilities for Hansen Transmissions (December 12, 2003)
Hansen Transmissions has moved to a new assembly and repair center, located in Verona, VA. According to the company?s press release, ... Read News
26 New Gearbox for Power Transmission Applications (April 24, 2006)
SIPCO Mechanical Linkage Solution launched its newest addition to the Technogear? product line. The new LC precision planetary series... Read News
27 New CEO at Hansen Transmissions (April 26, 2006)
Ivan Brems has been named CEO of Hansen Transmissions International NV. Since joining the Belgium-based company in 1993, Brems has hel... Read News
28 New Power Transmission Package from Brevini (April 14, 2005)
The new High Power Series from Brevini combines the gear design of the S Series planetary gearboxes with modular features of the PIV POSI... Read News
29 VDMA Reports Power Transmission Engineering Market Upswing (July 28, 2021)
At the board meeting of the VDMA Power Transmission Association on July 15, 2021, the sales forecast from the spring was increased from p... Read News
30 Hansen Transmissions Establishes Gearbox Facility in India (February 12, 2007)
Hansen Transmissions International announced plans to invest 170 million euros for a wind turbine production plant. The facility will sup... Read News
31 Sandvik Coromant CB7015 CBN Grade Delivers High Quality Finishing of Transmission Components (September 11, 2015)
Sandvik Coromant’s CB7015 is a CBN grade for a broad range of applications and designed to deliver optimal finish quality in the pr... Read News
32 SKF and SMT Collaborate on Software for Transmission Systems (April 24, 2020)
By combining SKF and SMT’s technical analysis and optimization capabilities, engineers can now have a seamless experience when desi... Read News
33 EMAG VLC 200 GT Offers Diverse Machining Concepts for Transmission Components (April 18, 2019)
It is no secret that e-mobility is a growing market. A current study by the consulting firm Strategy Analytics, predicts the production o... Read News
34 WABCO Signs Transmission Agreement with Daimler (January 17, 2019)
WABCO Holdings Inc., a supplier of braking control systems and other advanced technologies that improve the safety, efficiency and connec... Read News
35 Ricardo Invests in High Performance Transmission Manufacturing (November 15, 2018)
Ricardo has committed a further £1.5m in state-of-the-art spiral bevel grinding capability from Klingelnberg, building on the inves... Read News
36 Ricardo Delivers Transmissions for Japan Super Formula Series (July 26, 2018)
Japan’s Super Formula series – formerly known as Formula Nippon – is the top level of competitive single-seater racing ... Read News
37 Ricardo Delivers 100th Transmission for BMW M6 GT3 (June 12, 2018)
The BMW M6 GT3 made its first race outing at the 2016 24 Hours of Daytona and has since appeared at all of the top worldwide GT series,... Read News
38 Mahr Federal Depth Gaging Equipment Provide Wireless Data Transmission to Expedite Measurement Process (May 31, 2017)
Mahr Federal expands its line of wireless gaging products to include a range of depth gaging products. Digital Depth Gage MarCal 30 EWR, ... Read News
39 Regal Beloit to Acquire Power Transmission Solutions (December 30, 2014)
Regal Beloit Corporation recently announced it entered into a definitive agreement to acquire the Power Transmission Solutions business (... Read News
40 GM Plans $5.6 Billion Sale of Allison Transmission (June 28, 2007)
General Motors Corp. announced on June 28 it will sell its Allison Transmission commercial and military business to The Carlyle Group&nbs... Read News
41 Quality Transmission Components Rebranded as QTC Metric Gears (November 10, 2014)
Designatronics, Inc., a provider of complete mechatronic engineered solutions and services to the aerospace and defense, robotics, pac... Read News
42 Oerlikon Graziano Focuses on Transmission Solutions (July 16, 2013)
Since 1983, Oerlikon Graziano has manufactured more than 20 million synchronizer units for agricultural vehicles, construction equipment,... Read News
43 C & B Awarded Allison Transmission Order (February 3, 2011)
C & B Machinery has been awarded an order by Allison Transmission to build a "Flexible" double disc grinding cell for its C... Read News
44 Interface Designs and Simulates Complete Transmission (September 29, 2010)
Engineers are increasingly using a wide variety of software tools throughout the product lifecycle. To address customer requests and the ... Read News
45 Transmission Analysis Added to RomaxDesigner (July 15, 2010)
Design engineers are increasingly presented with more challenging scenarios, especially given automotive industry trends towards more eff... Read News
46 Ideal Gear and Machine Works Celebrates 90 Years Supporting Power Transmission Industry (August 21, 2009)
After 90 years, Ideal Gear and Machine Works looks to the future with new investments in people, expanded capacity and equipment, inclu... Read News
47 Chrysler and GETRAG Announce Joint Venture for 700,000 Dual Clutch Transmissions (July 2, 2007)
Chrysler Group’s vice president of powertrain manufacturing Richard Chow-Wah joined Indiana Gov. Mitch Daniels to name Tipton Count... Read News
48 Hansen Transmissions Appoints CEO (April 14, 2010)
Normal 0 false false false EN-US X-NONE X-NONE Micr... Read News