Multifaceted Evaluation of EV Drive Motor Shaft Produced by Radial Forging

User Benefits

- Improvement of processing technology and material strength can be expected by multifaceted analysis of hollow shafts manufactured by radial forging. - Evaluation of the mechanical properties of metal materials is possible by the precision universal testing machine and hardness tester. - Evaluation of the elemental distribution measurement and phase transformations related to improvement of the strength of metal materials is possible by EPMA and thermal analysis.

Introduction

Moves to achieve carbon neutrality to reduce greenhouse gas (GHG) emissions have accelerated in recent years. As part of this trend, the shift to electric vehicles (EVs) in the automotive industry is playing a major role in realizing a decarbonized society. Since improvement of the cruising range is required for wider adoption of EVs, auto body weight reduction has been taken up as a development theme. Reduction of the weight of EV shafts is a particularly important issue for development, as it does not simply improve the vehicle cruising range, but is also expected to improve motor response by reducing inertia. Radial forging is an innovative forging technology of hollow shaft which makes it possible to form the outer and inner diameters of parts at the same time by applying force from the radial direction of hollow shafts or hollow axis with a hammer (die) while simultaneously inserting a core bar into the shaft to transcribe the inner diameter shape 1). Hollow shafts produced by the radial forging process are attracting attention as next-generation shafts that satisfy both strength and weight reduction. In addition to the evaluation of the mechanical properties of motor shafts by the static tensile test and hardness test described in previous reports2),3), in this Application News, an elemental analysis using an electron probe microanalyzer (EPMA) and evaluation of thermal properties with thermal analysis instruments were newly conducted. This article introduces an example of a multifaceted evaluation of motor shafts comparing the results of various types of measurements.

June 29, 2023 GMT