Effect of grinding parameters on tooth surface waviness in continuous generating grinding for electric vehicle gears

Abstract

Compared with traditional fuel vehicle gears, electric vehicle (EV) gears in its transmission system suffer harsher working conditions with stricter quality demands. Especially, regarding the need for low noise, as an indispensable acceptance indicator in the EV gear manufacturing industry, tooth surface waviness of EV gears has received great attention. However, in continuous generating grinding (CGG), many factors affect tooth surface waviness and tooth surface waviness is still highly unpredictable. Therefore, aiming at improving the gear noise of EVs, the effect of grinding parameters (grinding speed, feed rate, and normal stock) on tooth surface waviness is clarified with other interferences eliminated. Considering the characterization of both CGG and tooth surface geometry, a tooth surface evaluation approach for a single tooth surface was proposed to characterize the meso-scale surface geometric unevenness and directly reflect the processing quality. A tooth surface waviness model was proposed to study the effect of grinding parameters on tooth surface waviness. In the model, the spatiotemporal variability characteristics in CGG are considered while ignoring system vibration, machine tool errors, and so on. By simulating the evolution process of the remaining flank stock, tooth surface topography is modeled, from which simulated tooth surface waviness is extracted. To verify the proposed tooth surface waviness model, the gear grinding experiments were conducted. Under different grinding parameters, the simulated tooth surface waviness is consistent with the experimental results in the length-domain and frequency-domain. Furthermore, it was found that grinding parameters change the flank mean value, flank peak-to-peak value, and profile mean value in length-domain, and influence the distribution pattern and amplitude of the spectrums in the frequency-domain. Profile tooth surface waviness was found to be influenced by grinding parameters irregularly and flank tooth surface waviness was found to be more susceptible to the change of normal stock in the length-domain and frequency-domain.