AGMA 22SP1 PDF

e-Drive gears differentiate from other automotive gears by two essential points: Higher Quality and the need for an excellent noise behavior.

Gear noise can have many causes. When gear noise issues occur, many people start to look for the causes in the manufacturing process only. However, this is not always the root cause. In order for a gearing system to function quietly, it must first be designed properly according to the load characteristics which will appear later in the real gear box. Hence, gear design assuming ideal conditions, i.e., parallel axes, no longer a guarantee for a quiet gear design. A much better approach is to employ loaded tooth contact analysis considering the true gear geometry, realistic loads and deformations of the gear box elements.

Even perfectly designed gears are subject to manufacturing errors that can also lead to gear noise often called “Ghost Noise”. Hence, it is important to have analysis tools capable to detect potential noise issues and to distinguish between manufacturing and design root causes. The gear inspection thus has another important task, namely the reliable detection of potential noise issues.

Typically, in conventional gear manufacturing quality control is carried out randomly, with only a few parts actually inspected. This is mainly due to the significantly longer measuring times in comparison to the actual production time and limited overall measuring capacity to cope with increased inspection demands. In order to guarantee process reliability, statistics are instead used to validate the process, resulting in a significant reduction of the permissible manufacturing tolerance in comparison to the drawing tolerance. In addition, constantly increasing power density requirements and the growing importance of excellent noise behavior of transmissions, especially in new e-drive concepts, has resulted in very tight tolerance requirements. Relying on statistical evaluation makes the production of such gears more challenging and expensive.

A new inspection concept developed by Gleason called “GRSL” (Gear Rolling System with Integrated Laser Technology) features the possible combination of double flank roll testing and laser scanning. With this completely new approach inspection now can be performed in parallel at the same speed to the time required for the hard finishing operation. As a result, 100% in-process inspection has become a reality, eliminating the need for statistical process evaluation. In addition, the measured data can be further evaluated concerning waviness in profile, lead and/or line of contact direction which allows the evaluation of the noise behavior Hence, this new system allows to do an up to 100% in-process noise analysis prediction of the finished gear. And even more, the measured gear deviations can be feed back into the design software to run a loaded tooth contact analysis under real conditions including the gear geometry with manufacturing errors superimposed.

This new revolutionary inspection concept has been integrated with a modern threaded wheel grinding machine and a fast and flexible automation system to create the HFC (Hard Finishing Cell) which features an automated Closed Loop correction system.