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Gear design has long been a "black art." The gear shop's modern alchemists often have to solve problems with a combination of knowledge, experience and luck. In many cases, trial and error are the only effective way to design gears. While years of experience have produced standard gearsets that work well for most situations, today's requirements for quieter, more accurate and more durable gears often force manufacturers to look for alternative designs.
Thereâ€™s a silly ongoing joke in the 2002 family film Spy Kids 2 (a movie that Iâ€™m admittedly not very proud Iâ€™ve seen, but hey, I was 12 at the time) involving a super advanced secret agent watch that does everything but tell time.
To ensure profitability and avoid losses, accurately quoting jobs is the first line of defense.
Understanding the differences of how the gear industry works in individual territories around the world is vital to any company that wishes to succeed on a global basis.
I have heard that X-ray diffraction does not tell the whole story and that I should really run a fatigue test. I understand this may be the best way, but is there another method that gives a high degree of confidence in the residual stress measurement?
Does anyone know where we can find a gear-shaped fruitcake? It's the holiday season again, and the Addendum staff has many friends. We'd like to get each of them the perfect holiday gift, something the demonstrates thought, caring and good will. Of course, we're looking for gifts with meaning, and for us, that can only mean gears.
Big gears, They drive the machinery that rolls steel, grinds limestone, pulverizes coal, pumps mud, mixes rubber, raises bridges and does many other heavy-duty industrial jobs. For 117 years, big gears have also driven the business of Horsburgh & Scott of Cleveland, OH.
How does one perform a contact analysis for worn gears? Our expert responds.
How does one determine the center of a worm and a worm wheel? Also, what are the differences between the common worm tooth forms?
Blogging is BIG and getting bigger all the time. There doesnâ€™t exist, for example, a news, industry, or entertainment entity that does not have at least one resident blogger. And now, since January -- we have ours.
The face load factor is one of the most important items for a gear strength calculation. Current standards propose formulae for face load factor, but they are not always appropriate. AGMA 927 proposes a simpler and quicker algorithm that doesn't require a contact analysis calculation. This paper explains how this algorithm can be applied for gear rating procedures.
Were Thomas Jefferson around today, he'd be all over the Double-A engine's development and everything it represents. And what is the Double-A engine; what does its successful design and execution represent, you ask?
Chamfering and deburring of cylindrical gears does not get much love from manufacturers. The process is seen as a necessary evil since it is adding cost without adding value. However, there are good reasons for not underrating this important auxiliary process. Chamfering and deburring takes care of several issues which may come up during the manufacture of quality gears.
The geometry of the bevel gear is quite complicated to describe mathematically, and much of the overall surface topology of the tooth flank is dependent on the machine settings and cutting method employed. AGMA 929-A06 â€” Calculation of Bevel Gear Top Land and Guidance on Cutter Edge Radius â€” lays out a practical approach for predicting the approximate top-land thicknesses at certain points of interest â€” regardless of the exact machine settings that will generate the tooth form. The points of interest that AGMA 929-A06 address consist of toe, mean, heel, and point of involute lengthwise curvature. The following method expands upon the concepts described in AGMA 929-A06 to allow the user to calculate not only the top-land thickness, but the more general case as well, i.e. â€” normal tooth thickness anywhere along the face and profile of the bevel gear tooth. This method does not rely on any additional machine settings; only basic geometry of the cutter, blank, and teeth are required to calculate fairly accurate tooth thicknesses. The tooth thicknesses are then transformed into a point cloud describing both the convex and concave flanks in a global, Cartesian coordinate system. These points can be utilized in any modern computer-aided design software package to assist in the generation of a 3D solid model; all pertinent tooth macrogeometry can be closely simulated using this technique. A case study will be presented evaluating the accuracy of the point cloud data compared to a physical part.
Look at that picture right over there on the right. Thatâ€™s one of the Bronze Wheels of Peru. Looks like a gear, doesnâ€™t it? If you knew nothing about it or the culture it sprang from and just happened to see it on the street, youâ€™d probably label it as such. So many people have had that same thought, in fact, that the set has picked up another name: the Bronze Gears of Peru.
Friction weighs heavily on loads that the supporting journals of gear trains must withstand. Not only does mesh friction, especially in worm gear drives, affect journal loading, but also the friction within the journal reflects back on the loads required of the mesh itself.
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.
In manufacturing, we all know that tracking statistics on your operation is essential for understanding how you're doing, as well as identifying areas for improvement. But what does the efficiency metric actually tell you?
Design and manufacture of gears is among the most complex and difficult disciplines of the industrial arts. From initial conception to machining and finishing, making gears ain't bean-bag. And guess what? Once those gears roll off the assembly line, it doesn't get any simpler. That's because gears - the metal ones at least - require the correct lubrication in order to prevent - or delay as long as possible - such things as wear, scuffing and Hertzian fatigue.
Induction hardening is becoming an increasingly popular alternative to thermochemical diffusion processes such as carburizing, and as it does so, manufacturers are on a never-ending quest to expand the scope of what's possible with the technology.
"If it ain't broke, don't fix it," goes the hoary bromide. But what if the time comes - and it most surely will - that in fact it is broke? Do you fix it or replace it? And when does gearbox maintenance and repair arrive at a point of diminishing returns and buying new is the answer?
In helicopter applications, the two-piece gear is typically joined by welding, bolts, or splines. In the case of the U.S. Army CH-47D Chinook helicopter, a decision was made to eliminate these joints through the use of integral design. Integral shaft spiral bevel gears must be designed such that the shaft does not interfere with gear tooth cutting and grinding. This paper discusses techniques to iterate in the design stage before manufacturing begins.
Depending on who you ask, the Industrial Internet of Things is growing more slowly than anyone predicted. Why is that, and what does that mean for the gear manufacturing industry?
Many people seem to be counting this year's Gear Expo in Nashville as a resounding success. There were 180 American and international exhibitors occupying over 50,000 square feet of exhibit space in the Nashville Convention Center, with total attendance of 2,700. This figure is dramatically down from past shows but that doesn't seem to be an issue with the show organizers. According to Kurt Medert, vice president of AGMA;s Administrative Division, even though attendance was off from the 1997 show, the exhibitors were pleased with the quality of the people who did come to the show. "This was an excellent show for us," said Marty Woodhouse, vice president of sales for Star Cutter Company and chairman of AGMA's Gear Expo committee. "Our customer base was there and they came to buy. It was very active."
This article illustrates a structural analysis of asymmetrical teeth. This study was carried out because of the impossibility of applying traditional calculations to procedures involved in the specific case. In particular, software for the automatic generation of meshes was devised because existing software does not produce results suitable for the new geometrical model required. Having carried out the structural calculations, a comparative study of the stress fields of symmetrical and asymmetrical teeth was carried out. The structural advantages of the latter type of teeth emerged.
If you think Y2K will mean the end of the world, forget it. General Vladimir Dvorkin recently said, "I'd like to apologize beforehand if I fail to realize someone's hopes for the Apocalypse." Te general was, of course, discussing Russian nuclear missiles, making the point that they are not going to launch or detonate when the calendar rolls over to January 1, 2000. General Dvorkin's American counterparts are similarly optimistic. While all that is a relief, it raises the question: will Y2K be as kind to the rest of society? And more specifically, will it be as kind to the gear industry? According to AGMA's president, Joe Franklin, the answer is a resounding "yes." According to Franklin, the AGMA Board considers Y2K a non-issue within an industry that is well ahead of others in its preparedness for January 1, 2000. But is it really? Does the gear industry understand the problem any better than other sectors of society? It's a relief to know that the nuclear bombs are not likely to fall within the first moments of the year 2000, but how about the computers and machines that keep the worldwide economy together?
Why Brushes? In this age of hi-tech, robots, automatic machines, machining cells, etc., is there a niche somewhere for power brushes? Let me answer by asking another question. What tool does the gear manufacturer have in his arsenal that allows him to deburr green gears, hardened gears, hobbed gears, ground gears and shaved gears? What tool allows him to deburr powder metal gears - green and sintered - brass gears, bronze gears, stainless gears made of exotic materials such as inconel, waspaloy, or hastaloy, and fiber and plastic gears? How about spur gears, helical gears, sprockets, both internal and external splines, clutch teeth and pump gears?
What does it mean to make "better" gears? Better gears more closely resemble the intended design parameters.
Despite increased overseas competition, there doesn't seem to be an urge among Americans to attend technical conferences.
In response to Ed Uberts letter, we have come a long way in gearing since WWII. The Europeans do use long addendum pinions in many cases. This modification does improve load capacity, sliding conditions and the working life of a gearset. When modifying a pinion tooth it is necessary to modify the gear tooth or adjust the center distance accordingly but we will leave that to the designers.
At its location in Roscoe, IL, the Forest City Gear facility is surrounded by wildlife splendor. Fruit trees, nature walks and the occasional cute and furry animal sighting create an unlikely landscape for a manufacturing site. Of course, cavorting with the cute and furry does have its drawbacks.
The world is full of acronyms. At work, the inbox reveals e-mails from the AWEA, SAE, MPIF and AMT. On the weekends, Saturday mornings are consumed by activities involving the AYSO, PTA, YMCA or DMV. Itâ€™s a struggle to determine what organization does what and why we should care in the first place.
Micropitting has become a major concern in certain classes of industrial gear applications, especially wind power and other relatively highly loaded, somewhat slow-speed applications, where carburized gears are used to facilitate maximum load capacity in a compact package. While by itself the appearance of micropitting does not generally cause much perturbation in the overall operation of a gear system, the ultimate consequences of a micropitting failure can, and frequently are, much more catastrophic.
If the free iPad giveaway from FANUC doesnâ€™t draw you in, the wall-to-wall new machine tool technology displays should have you stopped dead in your tracks. To be exact, there will be 1.2 million square feet of exhibit space that may have your jaw dropping. IMTS may be the last show you want to forget to bring walking shoes to.
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.
Thousands of miles from here, a political and religious leader has ordered a man killed. The Ayatollah Khomeini is offended by a book Salman Rushdie has written; therefore, he has decided this author must die. So what? Executions are ordered all the time in this world. The man who signed this order doesn't interest me. Neither does the book. It's all happening in another country. It has nothing to do with me.
The cutting tool industry has undergone some serious changes in the last couple of years in both technology and the way the industry does business. The emerging technology today, as well as for the foreseeable future, is dry cutting, especially in high volume production settings. Wet cutting continues to be as popular as ever with lubrication advances making it more economical and environmentally friendly. There has also developed a process called "near dry cutting." this process offers many of the benefits of fluids while eliminating many of hte associated problems.
Taxes may be one of the only two sure things in life, but that doesn't make them popular. Nobody is happy to pay them, and the bigger the amount due, the unhappier the taxpayer. Conversely, politicians know that coming out in favor of a tax cut is the equivalent of voting for apple pie and motherhood. It's a sure-fire success at the ballot box.
Cutter Sharpening Cutter sharpening is very important both during manufacturing and subsequently in resharpening after dulling. Not only does this process affect cutter "over cutting edge" quality and the quality of the part cut, but it can also affect the manner in which chip flow takes place on the cutter face if the surface finished is too rough or rippled.
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.
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.
The availability of technical software has grown rapidly in the last few years because of the proliferation of personal computers. It is rare to find an organization doing technical work that does not have some type of computer. For gear designers and manufacturers, proper use of the computer can mean the difference between meeting the competition or falling behind in today's business world. The right answers the first time are essential if cost-effective design and fabrication are to be realized. The computer is capable of optimizing a design by methods that are too laborious to undertake using hard calculations. As speeds continue to climb and more power per pound is required from gear systems, it no longer is possible to design "on the safe side" by using larger service factors. At high rotational speeds a larger gear set may well have less capacity because of dynamic effects. The gear engineer of today must consider the entire gear box or even the entire rotating system as his or her domain.
Worm gears are among the oldest types of gearing, but that does not mean they are obsolete, antiquated technology. The main reasons for the bad experiences some engineers have with worm gearing are misapplication and misuse. No form of gearing works for every application. Strengths and weaknesses versus the application must be weighed to decide which form of gearing to use. For proper application and operation of worm gears, certain areas that may differ from other types of gearing need to be addressed.
Another year has passed and, because of the short term ups and downs of the economy, it's still hard to judge whether we are in an appreciably different place than we were a year ago. The economy doesn't seem to be worse than it was, but it also doesn't seem to be a whole lot better.
When designing a gear set, engineers usually want the teeth of the gear (Ng) and the pinion (Np) in a "hunting" mesh. Such a mesh or combination is defined as one in which the pinion and the gear do not have any common divisor by a prime number. If a mesh is "hunting," then the pinion must make Np x Ng revolutions before the same pinion tooth meshes with the same gear space. It is often easy to determine if a mesh is hunting by first determining if both the pinion and the gear teeth are divisible by 2,3,5,7,etc. (prime numbers). However, in this age of computerization, how does one program the computer to check for hunting teeth? A simple algorithm is shown below.
How does one select the correct size of hob/gashing cutter like hob OD, length and number of flutes for teeth cutting process based on tip circle diameter and face width of job?
News Items About DOE
1 Non-Coplanar Connecting Rod System Does the Work of Three Machines (July 21, 2011)
C & B Machinery of Livonia, Michigan has improved productivity and flexibility of their double disc non-coplanar connecting rod grind... Read News