bearings - Search Results

Articles About bearings

Articles are sorted by RELEVANCE. Sort by Date.

1 Analysis of Load Distribution in Planet Gear Bearings (September 2011)

In epicyclic gear sets designed for aeronautical applications, planet gears are generally supported by spherical roller bearings with the bearing outer race integral to the gear hub. This article presents a new method to compute roller load distribution in such bearings where the outer ring can’t be considered rigid.

2 Comparing Surface Failure Modes in Bearings and Gears: Appearances vs. Mechanisms (July/August 1992)

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.

3 Bearings Education - A Lot to Learn (June/July 2013)

Bearings ain't beanbag. They are complicated. They are big-business. They are often counterfeited. They are used in virtually anything that moves. But it is the "complicated" part that challenges OEMs, job shops and other operations, and, most of all, their employees. Add to that the countless other entities around the world that are intimately involved with bearings and you can arrive at a semblance of an idea of just how important these precious orbs can be to a successful operation.

4 Morphology of Micropitting (November/December 2012)

Understanding the morphology of micropitting is critical in determining the root cause of failure. Examples of micropitting in gears and rolling-element bearings are presented to illustrate morphological variations that can occur in practice.

5 NASA Gets Down and Dirty for SARJ Solution (September/October 2008)

For more than 10 months, NASA ground engineers and International Space Station (ISS) astronauts have been struggling with a perplexing malfunction of one of the station’s two solar array rotary joints (SARJ).

6 Misalignment No Beauty in Gearsets (May/June 1991)

When we have problems with gearset failure, a common diagnosis is misalignment. What exactly is that and how do we prevent it? The second most common "killer" of good gear sets is misalignment (dirt, or abrasive wear, is first). Gear teeth simply won't carry the load if they don't touch, and the portion that does touch has to carry an overload to make up for the missing contact area.

7 Gear Teeth as Bearing Surfaces (May 2017)

A reader wonders about gears where the tops of the teeth are the bearing surface, as used in spur gear differentials. Do they require any special construction or processing?

8 How Bearing Design Improves Gearbox Performance (September 2012)

Gearbox performance, reliability, total cost of ownership (energy cost), overall impact on the environment, and anticipation of additional future regulations are top-of-mind issues in the industry. Optimization of the bearing set can significantly improve gearbox performance.

9 Tooth Contact Shift in Loaded Spiral Bevel Gears (November/December 1992)

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.

10 Effects of Planetary Gear Ratio on Mean Service Life (July/August 1998)

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.

11 How to Minimize Power Losses in Transmissions, Axles and Steering Systems (September 2012)

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.

12 Mechanical Behavior and Microstructure of Ausrolled Surfaces in Gear Steels (March/April 1995)

Ausforming, the plastic deformation of heat treatment steels in their metastable, austentic condition, was shown several decades ago to lead to quenched and tempered steels that were harder, tougher and more durable under fatigue-type loading than conventionally heat-treated steels. To circumvent the large forces required to ausform entire components such as gears, cams and bearings, the ausforming process imparts added mechanical strength and durability only to those contact surfaces that are critically loaded. The ausrolling process, as utilized for finishing the loaded surfaces of machine elements, imparts high quality surface texture and geometry control. The near-net-shape geometry and surface topography of the machine elements must be controlled to be compatible with the network dimensional finish and the rolling die design requirements (Ref. 1).

13 Critique of the ISO 15144-1 Method to Predict the Risk of Micropitting (March/April 2016)

There exists an ongoing, urgent need for a rating method to assess micropitting risk, as AGMA considers it a “a very significant failure mode for rolling element bearings and gear teeth — especially in gearbox applications such as wind turbines.”

14 KISSsoft Update Integrates Parasolid CAD Core (May 2010)

The machine element package by KISSsoft for the design and optimization of components like gears, shafts, bearings and others is now available in the new version 04/2010.

15 Design of Oil-Lubricated Machine Components for Life and Reliability (November/December 2007)

This article summarizes the use of laboratory fatigue data for bearings and gears coupled with probabilistic life prediction and EHD theories to predict the life and reliability of a commercial turboprop gearbox.

16 Maximum Life Spiral Bevel Reduction Design (September/October 1993)

Optimization is applied to the design of a spiral bevel gear reduction for maximum life at a given size. A modified feasible directions search algorithm permits a wide variety of inequality constraints and exact design requirements to be met with low sensitivity to initial values. Gear tooth bending strength and minimum contact ration under load are included in the active constraints. The optimal design of the spiral bevel gear reduction includes the selection of bearing and shaft proportions in addition to gear mesh parameters. System life is maximized subject to a fixed back-cone distance of the spiral bevel gear set for a specified speed ratio, shaft angle, input torque and power. Significant parameters in the design are the spiral angle, the pressure angle, the numbers of teeth on the pinion and gear and the location and size of the four support bearings. Interpolated polynomials expand the discrete bearing properties and proportions into continuous variables for gradient optimization. After finding the continuous optimum, a designer can analyze near-optimal designs for comparison and selection. Design examples show the influence of the bearing lives on the gear parameters in the optimal configurations. For a fixed back-cone distance, optimal designs with larger shaft angles have larger service lives.

17 Longitudinal Load Distribution Factor for Straddle- and Overhang-Mounted Spur Gears (July/August 1987)

A pair of spur gears generally has an effective lead error which is caused, not only by manufacturing and assembling errors, but also by the deformations of shafts, bearings and housings due to the transmitted load. The longitudinal load distribution on a contact line of the teeth of the gears is not uniform because of the effective lead error.

18 Finishing of Gears by Ausforming (November/December 1987)

Almost all machines or mechanical systems contain precision contact elements such as bearings, cams, rears, shafts, splines and rollers. These components have two important common requirements: first, they must possess sufficient mechanical properties, such as, high hardness, fatigue strength and wear resistance to maximize their performance and life; second, they must be finished to close dimensional tolerances to minimize noise, vibration and fatigue loading.

19 AGMAs Go-To Gear Guys (September/October 2016)

While the two have taught a variety of AGMA courses over the years, without question their most popular courses are Gear Failure Analysis (Errichello with longtime colleague Jane Muller) and Gearbox CSI: Forensic Analysis of Gear & Bearing Failures (Drago). Drago currently teaches Manufacturing & Inspection (with AGMA instructor Joseph W. Lenski, Jr.) and Gearbox System Design: The Rest of the Story… Everything but the Gears and Bearings (with AGMA instructor Steve Cymbala) as well.

News Items About bearings

1 SKF’s New Cylindrical Roller Bearings Extend Wind Turbine Gearbox Life (April 11, 2006)
New SKF high-capacity cylindrical roller bearings for wind turbine gearboxes have been engineered to promote longer gearbox service life... Read News

2 NSK Introduces New Bearings (April 13, 2005)
[photo] NSK's new BGR Series of super precision angular contact bearings combines the benefits of SHX heat and seizure resistant stee... Read News

3 SKF’s New Ball Bearings Reduce Noise in Air Handling Applications (April 15, 2006)
SKF? ConCentra ball bearing units for high-speed air handling applications integrate unique concentric locking technology to form a near ... Read News

4 Steinmeyer Introduces New Ball Bearings (January 9, 2007)
Steinmeyer Inc. announced an addition to its standard line of miniature precision screws ? the "world's smallest commercially availab... Read News

5 2010 Metal Powder Testing and Bearings Standards Released (January 5, 2010)
The 2010 editions of Standard Test Methods for Metal Powders and Powder Metallurgy (PM) Products, and Standard 35, Materials Standards fo... Read News

6 GH Gear/Raceway Hardening Machine Handles Large Bearings More Productively (April 24, 2008)
GH Induction Group recently shipped a new design gear/raceway hardening machine capable of hardening gears and bearing raceways up to 3... Read News

7 KISSsoft and SKF Collaborate on Rolling Bearings Data (May 24, 2016)
The new version of KISSsoft 03/2016 now contains the very latest data from the "Rolling Bearings" catalog. By cooperation betwe... Read News