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.
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.
Electrification has already started to have a noticeable impact on the global automotive industry. As a result, the drivetrains of hybrid (HEV) and full electric vehicles (EV) are facing many challenges, like increased requirements for NVH in high speed e-Drives and the need for performance improvements to deal with recuperation requirements. Motivated by the positive validation results of surface densified manual transmission gears which are also applicable for dedicated hybrid transmissions (DHTs) like
e-DCTs, GKN engineers have been looking for a more challenging application
for PM gears within those areas.
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.
Ground bevel and hypoid gears have a designed motion error that defines parts of their NVH behavior. The surface structure is defined by the hard finishing process.
Which transmission system will come out on top is a hot topic in the automotive community. With multiple transmission-centric conferences on the horizon, there will be plenty of debate, but how much will the answer actually affect gear manufacturers, and when?
This paper presents a new approach to repair industrial gears by showing a case study where pressure angle modification is also considered, differently from the past repairing procedures that dealt only with the modification of the profile shift
coefficient. A computer program has been developed to automatically determine the repair alternatives under two goals: minimize the stock removal or maximize gear tooth strength.