Study of Increase in Drag Torque at High Rotational Speed of Wet Multi-Plate Clutch Part3

Hirofumi Ebisumoto･Hitoshi Tamegai･Tomohiro Yoshizue (Mazda)

This report describes the drag characteristics of wet multi-plate clutch in automatic transmission when they are released. The drag torque of the clutch may increase at high rotational speed. At that time, plate vibration may be seen, which is considered to be the cause of the increase in drag torque. We modeled this plate vibration by coupled CFD and vibration analysis. And measured the vibration with a high-speed camera and verified the model. Thereby, the vibration mechanism was clarified.

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

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

Electrical pitting has been occurred on the torque transmission path incoming electric current due to the electrification, and is expected to be apparent in the future. While developing countermeasure solution either isolation or conductive items for electrical pitting, these measures are conducted either a certain period of maintenance or after noticing defect on testing. Prevention design for electrical pitting on bearing aiming optimal design from early stage of design study was developed.

Influence of Speed Ratio on Pitching Angle of Elements of Metal Pushing V-Belt Type CVT under Steady-State

Ryota Matsuda･Kazuya Okubo･Kiyotaka Obunai (Doshisha University)

The objective of this study was to investigate the influence of speed ratio on slip ratio between pulleys of metal pushing V-belt type CVT under steady-state. Relative pitch angel was calculated with referring to the data of acceleration measured by a 3-axis acceleration sensor attached to the element. Revolution speeds of the driving and driven pulley were measured by the rotational speed sensors. The nominal slip ratio defined as the difference between revolution speeds of two pulleys was increased due to increasing absolute relative pitch angle.

Quantification of the Influence of Factors on Abnormal Austenite Grain Growth in Carburized Steel Parts for Drivetrain

Yasuo Itou･Gou Katou･Makoto Maeda (JATCO)

Carburized components formed by cold forging can sometimes exhibit abnormal austenite grain growth, which leads to a decrease in strength. Although the influencing factors are qualitatively known, their degree of impact is not clear. Therefore, using test specimens that simulate the component manufacturing process, we experimentally clarified the relationship between each influencing factor and the austenite grain size after carburization.

Prediction of Abnormal Grain Growth in Carburized Components using Bayesian Networks

Akira Mizuno･Gou Katou･Makoto Maeda (JATCO)･Takumi Yoshida･Tsubasa Yamashita･Shuhei Kojima (MI-6)･Junya Inoue (The University of Tokyo)

Abnormal grain growth, which leads to a decrease in the strength of drivetrain carburized components, is a complex phenomenon that makes its occurrence difficult to predict. In this study, we developed a method to predict the occurrence of abnormal grain growth by constructing a Bayesian network and training it using test piece data that simulates cold forging, based on the material properties and manufacturing conditions.