Gear Rattle Noise Analysis Based on Electric Automotive Drivetrain Model

Takeshi Watanabe･Sachio Wada･Tsuyoshi Shinohara･Yoshiyuki Yomogida (SUBARU)

Battery Electric Vehicles (BEVs) are known for their excellent motor response and acceleration．However，gear rattle noise remains a significant challenge．This research provides a detailed model-based analysis of the mechanisms behind gear rattle noise．It indicates the gear rattle behaviors and also presents methods to achieve a high level of balance between vehicle acceleration response and gear rattle noise reduction．

Control Method that Achieves High Acceleration Response and Low Gear Rattle Noise of Electric Vehicles

Yu Takano･Keigo Yamada･Hajime Ishii (SUBARU)

Battery Electric Vehicles (BEVs) are known for their excellent motor response and acceleration. However, gear rattle noise remains a significant challenge. This research provides a control method that achieves a high-dimensional balance between acceleration response and gear rattle noise from mechanisms of the noise.

Auxiliary Brake Apparatus by Air Compression and Release for Stop of Heavy FCV Regenerative Brake (5th Report)
-Two-stage compression system for high brake power-

Chinatsu Sano･Hiroshi Uchida･Toshinori Fujita･Takashi Shibayama (Tokyo Denki University)

A simple structure auxiliary brake by utilizing air compression and release cycle had been proposed in last four reports to prepare for the case of FCV truck regenerative brake failure . In this report, it has been clarified that doubled braking capacity can be achieved without super charge inlet air by adopting two-stage compression system using both end of the compression piston for air compression. The test result will be reported.

Mechanism Analysis of Vehicle Dynamics Using Front-Rear and Left-Right Differential Rotation Constraints for AWD

Kai Kadono･Yusuke Yabusaki･Tomohiro Shimizu･Akira Ono･Satoru Sugiyama･Susumu Ito･Masami Oguri (SUBARU)

This paper investigates the impact on vehicle dynamics caused by the combination of limitations in speed differentials between the left and right, and front and rear wheels of an all-wheel-drive vehicle under snowy conditions. Based on the verification results, the magnitude of the influence of each on vehicle behavior and how to use them differently and cooperate with each other were examined. These combination variants could contribute to optimizing all-wheel-drive control to enhance vehicle stability and steering response on low-friction road surfaces.

Development of the Surrogate Model for Bolt Loosening in Differential Case Ring Gears by Integrating Generative Shape AI and Principles

Kazumasa Watanabe･Tomofumi Shimokawa (Toyota Motor)･Koji Iwayama･Takayuki Onojima (Shiga University)･Hiroaki Tashiro･Hiromasa Ueno･Takahiro Mochihara (Toyota Motor)

We have developed the surrogate model that rapidly predicts bolt loosening in differential case ring gears for design shapes by integrating latent variables and theoretical equations using Generative Shape AI. Furthermore, we report the establishment of the method to generate shapes that meet specified bolt loosening performance criteria.

Numerical prediction of the oil flow accelerated by the momentum received between gear teeth

Yoshihiro Kato･Tadanobu Ueda (Toyota Central RandD Labs.)

In numerically analyzing oil flow stirred by rotating gears, a major challenge lies in predicting the acceleration of oil caused by the reactive forces and the centrifugal forces acting between the gear teeth. To address this issue, we apply the volume of fluid (VOF) method to simulate fluid-gas two-phase flow and calculate the oil flow stirred by a single rotating gear. By comparing the numerical results with velocity measurements, we examine the sources of numerical error and explore ways to improve the prediction technique.

Prevention Design of Electrical Erosion in Deep Groove Ball Bearing for Electric Powertrain（Second Report）

Hideyuki Shiraku･Takahiro Kuwabara･Satoshi Takemoto (Nissan Motor)

Electricity can lead to electrical erosion in bearings due to the electrification of the powertrain. The issue of the electrical erosion is anticipated to be apparent due to high power motor in the future. To implement the optimal design and improve the efficiency of technical development from the beginning of development, we tackled quantitative prevention design for electrical erosion based on the discharge energy.