Addressing one of the most talked about noise sources — gears.

Physical effects causing transmission noise.

Physical effects that cause transmission noise.

Gear noise is a common evil any gear manufacturer must live with. It is often low enough not to be a major problem but, at times, gear whining may appear and then, tracking the source and, especially, curing the ill can be tricky at best.

The design of gear blanks or flanges has traditionally been driven by weight reduction. Recently innovative companies have started to use the gear blank design to tune the system dynamics to reduce gear whine.

A meaningful discussion about noise is quite difficult because the impression of "noise" is quite subjective. Everybody has a lifetime experience with sound / noise and sees themselves as an expert.

Gear noise is among the issues of greatest concern in today's modern gearboxes. Significant research has resulted in the application of enhancements in all phases of gear manufacturing, and the work is ongoing. With the introduction of Electric Vehicles (EV), research and development in this area has surged in recent years. Most importantly, powerful new noise analysis solutions are fast becoming available.

Noise issues from gear and motor excitation whine are commonly faced by many within the EV and HEV industry. In this paper the authors present an advanced CAE methodology for troubleshooting and optimizing such NVH phenomenon.

Question: I am a gear engineer for a motor manufacturer in China. I am writing about noise generated from cross-helical gear assembly error. I want to learn the relationship between the misalignment (center distance change and cross-angle shift) and transmission error. It is better under the loading and theory conditions. What is the trend of cross-helical gear development (use ZI worm and involute helical gear, point contact)?

In order to reduce costs for development and production, the objective in gearbox development and design is to predict running and noise behavior of a gearbox without manufacturing a prototype and running expensive experimental investigations. To achieve this objective, powerful simulation models have to be set up in a first step. Afterwards, those models have to be qualified and compared to experimental investigations. During the investigation procedure of gearboxes, there are two possibilities to evaluate the running and noise behavior: quasi-static and dynamic investigations. In times of engine downsizing, e-mobility and lightweight design, the dynamic excitation behavior is becoming increasingly important.