This paper presents two new techniques for
aligning and maintaining large ring gears. One technique uses lubricant temperature analysis, and the other uses stop action photography.
Hobbing is probably the most popular gear manufacturing process. Its inherent accuracy and productivity makes it
a logical choice for a wide range of sizes.
Your May/June issue contains a
letter from Edward Ubert of Rockwell
International with some serious questions
about specifying and measuring tooth thickness.
The fundamental purpose of gear
grinding is to consistently and economically produce "hard" or "soft" gear tooth elements within the accuracy required by the gear functions. These gear elements include tooth profile, tooth spacing, lead or parallelism, axial profile, pitch line runout, surface finish, root fillet profile,
and other gear geometry which contribute
to the performance of a gear train.
As we approach the problem of hard gear processing, it is well to take a look at the reason for discussing it at this time. In our present economic atmosphere throughout the world, more and more emphasis is being placed upon efficiency which is dictated by higher energy costs.
The gear hobbing process is a generating type of production operation. For this
reason, the form of the hob tooth is
always different from the form of the
tooth that it produces.
Material losses and long production times are two areas of conventional spur and helical gear manufacturing in which improvements can be made. Metalforming processes have been considered for manufacturing spur and helical gears, but these are costly due to the development times necessary for each new part design. Through a project funded by the U.S. Army Tank - Automotive Command, Battelle's Columbus
Division has developed a technique for designing spur and helical gear forging and extrusion dies using computer aided
techniques.
The Integral Temperature Method for the evaluation of the scoring load capacity of gears is described. All necessary equations for the practical application are presented. The limit scoring temperature for any oil can be obtained from a gear scoring test.