The Development of a Integration Method for Hollow Rotor Shafts by Warm Flow Forming

Naoto Taguchi･Tomoyoshi Naganawa (Nissan Motor)･Koji Higaki･Takuya Yamazaki (Nihon Spindle Manufacturing)

Various types of motors are used in electric vehicles, but in order to operate the motor in a higher efficiency state, measures for higher rotation are required. In addition, since high temperature is generated when the rotor-shaft is operated at high rotation, there is a need to provide a cooling structure in the rotor shaft. This paper reports an example of application development of warm flow forming method to manufacture rotor shafts incorporating these requirements at lower cost.

Research on Cutting Conditions via Simulation by Bayesian Optimization

Hisao Eto･Yoshihiro Ohnishi･Takeo Miyaguchi (ITOCHU Techno-Solutions)

The cutting simulation has played the big role in the manufacturing field. Our group has been focusing on the modeling via Physics-Based Methods on CAD/CAM. In this presentation many cutting tests are done by the cutting simulations. Simulation results become like the big data so any knowledge about cutting process might be able to be found from such data. It is benefit that the many cases are done without actual tests by the simulation. However, this takes a long time. Therefore, we tried the Bayesian Optimization to consider the simulation results by not so big data.

Development of High-speed Prediction System using Surrogate Models for Magnet Wire Forming

Shintaro Nakano･Toshiki Terabe･Le Dinh Thanh (Toyota Motor)

This study presents a high-speed prediction system using surrogate models for coiled wire forming. First, we confirmed that CAE results coincide with the real. Next, we constructed the surrogate model using a Convolutional Neural Network (CNN) and CAE data taken from CAE results. The surrogate models can provide prediction on strain distribution within 10% error, while reduce computation time from days to seconds. It is highly expected that using such surrogate models, motor development period can be significantly shortened.

A Study on the Influence of Initial Tightening Force Variation in Calibrated Wrench Method

Soichi Hareyama･Ken-ichi Manabe･Satoshi Kobayashi (Tokyo Metropolitan University)

When tightening a large number of bolts, the torque coefficient or friction coefficient and tightening torque have a significant effect on the variation of the initial clamping force (initial axial tension). The coefficient of friction is affected by the lubrication conditions during tightening and the machining accuracy of the bolt and nut. The tightening torque is the product of the distance to the force point of the torque wrench and the force acting on it, and is considered to be a variable independent of the torque coefficient and other factors. Although there are many studies on the friction coefficient and torque coefficient, the variation of tightening torque has not been studied in detail. In this study, we first examine the effects of errors in the position of the force point and the direction of the force of the torque wrench and the tool itself on the tightening torque. Next, the influence on the variation of tightening torque based on the tightening operation, i.e., human error, is examined, in which a simple tightening test was performed by three workers. The results of the study and the variation of tightening torque based on the test results are organized as 90% confidence limits.

Effect of Panel Curvature and Thickness on Outer Panel Sink Mark by Mastic Adhesive

Takashi Iwama･Kentaro Sato･Yoichiro Ohnishi･Tsuyoshi Shiozaki (JFE Steel)･Keigo Unoki･Hiroki Toriyama･Takafumi Watanabe･Kenichi Matsunaga (Toyota Motor Kyushu)

When the mastic hardens and shrinks during the painting process, sink mark caused by the retraction of the outer panel becomes an issue. Panel thickness is known to be a factor that affects sink mark, but the influence of design curvature has not been clarified.
The influence of design curvature on sink mark was investigated by experiments using a laboratory model and CAE. It became clear that the effect of design curvature on distortion was greater than that of panel thickness.