This article was originally published 20 years ago, in Gear Technology’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
“transmission error,” is responsible for excitation of gear noise and problems of gear accuracy and sometimes has a relationship to gear failure.
High demands for cost-effectiveness and improved product quality can be achieved via a new low pressure
carburizing process with high pressure gas quenching. Up to 50% of the heat treatment time can be saved. Furthermore, the distortion of the gear parts could be reduced because of gas quenching, and grinding costs could be saved. This article gives an overview of the principles of the process technology and the required furnace technology. Also, some examples of practical applications
are presented.
Gear designs are evolving at an ever accelerating rate, and gear manufacturers need to better understand
how the choice of materials and heat treating methods can optimize mechanical properties, balance overall cost and extend service life.
The following article is concerned with the analysis of the wear-reducing effect of PVD-coatings in gearings. Standardized test methods are used, which under near-real conditions enable
statements to be made about the different forms of damage and wear (micropitting, macropitting, scuffing).
Excess lubricant supply in gearing contributes to power loss due to churning as well as the requirements of the lubrication system itself. Normally, a much larger amount of oil than required is used for cooling because so much of it is thrown away by centrifugal force. To lower the amount of lubricant required and
reduce those losses, it is necessary to discover the ideal location of the supplying nozzle.
To meet the future goals of higher productivity and lower production costs, the cutting speeds and feeds in modern gear hobbing applications have to increase further. In several cases, coated carbide tools have replaced the commonly used high speed steel (HSS) tools.
Load-carrying capacity of gears, especially the surface durability, is influenced by their tooth surface
roughness in addition to their tooth profiles and tooth traces.