In this discussion of gear roll-finishing particular attention is called to the special tooth nomenclature resulting from the interaction between the rolling die teeth and the gear teeth. To eliminate confusion the side of a gear tooth that is in contact with the "approach" side of a rolling die tooth is also considered to be the approach side. The same holds true for the "trail" side. Thus, the side of the gear tooth that is in contact with the trail side of a rolling die is also considered to be the trail side.
The load capacity rating of gears had its beginning in the 18th century at Leiden University when Prof. Pieter van
Musschenbroek systematically tested the wooden teeth of windmill gears, applying the bending strength formula published by Galilei one century earlier. In the next centuries several scientists improved or extended the formula, and recently a Draft International Standard could be presented.
Today it is common practice when
climb hobbing to keep the direction of
the hob thread the same as that of the
helical gear. The same generalization
holds true for the mass production of
gears for automobiles. It is the authors' opinion, however, that conventional hobbing with a reverse-handed hob is more effective for the high-speed manufacture of comparatively small module gears for automobiles. The authors have proven both experimentally and theoretically that reverse-handed conventional hobbing, using a multi-thread hob with a smaller diameter is very effective for lengthening the life of the hob and for increasing cutting efficiency at high speeds.
A change has taken place within the industry that is going to have an enormous effect on the marketing, sales, and purchasing of gear manufacturing and related equipment. This change was the American Gear Manufacturers' Association, first biennial combination technical conference and machine tool minishow.
Inviting an American shipbuilding industry official to discuss the subject of meeting foreign competition is like inviting Jackie Gleason to speak on dieting. I am painfully aware of the commercial shipbuilding industry situation. Let me tell you a little about it.
Now that the new tax bill has been passed, the time has come to begin evaluating how it will affect investment strategies in the machine tool business. Your first reaction may be to think that any motivation to invest in capital improvements in your company is gone, because both the investment tax credit and the accelerated depreciation on capital investment have been removed from the tax law. After all, if Uncle Sam is not going to help us out through some short term tax gains, why should we bother? Can we afford to bother?
In robot configurations it is desirable to be able to obtain an arbitrary orientation of the output element or end-effector. This implies a minimum of two independent rotations about two (generally perpendicular) intersecting axes. If, in addition, the out element performs a mechanical task such as in manufacturing or assembly (e.g., drilling, turning, boring, etc.) it may be necessary for the end-effector to rotate about its axis. If such a motion is to be realized with gearing, this necessitates a three-degree-of-freedom, three-dimensional gear train, which provides a mechanical drive of gyroscopic complexity; i.e., a drive with independently controlled inputs about three axes corresponding to azimuth, nutation, and spin.
Curvic Couplings were first introduced in 1942 to meet the need for permanent couplings and releasing couplings (clutches), requiring extreme accuracy and maximum load carrying capacity, together with a fast rate of production. The development of the Curvic Coupling stems directly from the manufacture of Zerol and spiral bevel gears since it is made on basically similar machines and also uses similar production methods. The Curvic Coupling can therefore lay claim to the same production advantages and high precision associated with bevel gears.
"It's show time!" Ready or not, on Sept 3, the biennial International Machine Tool Show opens at McCormick Place, Chicago. Planning a show that encompasses displays from over 1000 companies from 29 nations and an associated technical conference presenting more than 200 papers on 50 topics has not been without its problems.
At the present time, technology seems to be moving faster than our ability to educate people in its utilization. this is particularly true of the manufacturing engineering profession.