Launch of New Evaluation Solution Supporting Higher Rotational Speeds for EV Drive Units

JFE Techno-Research Corporation (Headquarters: Chiyoda-ku, Tokyo; President: Kazuhiro Seto) is launching a new solution to address the increasing rotational speeds of EV drive units. This is achieved by integrating the specialized motor evaluation technology developed by JFE Techno-Research—based on material evaluation and measurement techniques cultivated in the steel industry—with the high-speed motor dynamo testing technology provided by Technical Support Co., Ltd. (Headquarters: Hamamatsu, Shizuoka; President: Masazumi Yamamoto). This technology captures high-speed footage of the actual behavior of cooling and lubricating oil supplied to gears in high-rotation environments of up to 24,000 rpm, and evaluates this data in combination with numerical analysis (fluid analysis), providing new insights for cooling and lubrication design under high-rotation conditions, where development is expected to accelerate.

[Background and Technical Features] In recent years, the drive for smaller units to increase the flexibility of vehicle body design has led to rapid advancements in high power density and miniaturization of the motors, inverters, and reduction gears that make up e-Axles. Since motor output is the product of torque and rotational speed, the industry as a whole is accelerating the shift toward higher motor speeds to achieve weight reduction and higher efficiency. On the other hand, higher speeds create numerous technical challenges, including heat generation, vibration, insulation, and strength, making the optimization of gear cooling and lubrication a critical theme.

The primary feature of this new solution is the ability to visualize and improve the analytical accuracy of gear cooling and lubrication mechanisms. By utilizing the high-speed dynamo testing technology held by Technical Support Co., Ltd., along with the specialized measurement using high-speed cameras and fluid analysis technology held by our company, we can observe in detail how cooling oil dripped onto gears adheres and scatters during high-speed rotation, and to what extent it is supplied to the tooth surfaces. In the experiments, ATF (Automatic Transmission Fluid) was used as the test oil, employing a drip method with controlled droplet size and supply volume, conducted at room temperature (temperature adjustments are also possible).

[Test Configuration] ● Test Gear: Gear for e-Axle ● Test Oil: ATF ● Maximum Rotational Speed: 24,000 rpm ● Cooling/Lubrication Method: Droplet (Liquid volume and size adjusted via pump and nozzle diameter) ● Liquid Temperature: Room temperature (Please consult separately for variable temperature requirements) ● Imaging: High-speed camera ● Analysis Tool: Particleworks 8.1

[Expected Effects] This solution is expected to be utilized by automotive and parts manufacturers for the "development of new cooling and lubrication mechanisms," "evaluation of cooling oil reach and adhesion," "design optimization and efficiency improvement of conventional systems," and "improvement of analysis accuracy," thereby contributing to the reliability and efficiency of EV drive units. In addition to this cooling oil behavior visualization technology, our company is the only evaluation organization in Japan capable of providing comprehensive support from specialized motor measurements to material evaluation and analysis. This includes our proprietary technologies such as "strain visualization technology for motors during high-speed rotation," "motor vibration analysis via air-gap magnetic flux measurement," and "motor shaft voltage measurement and electrolytic corrosion acceleration testing due to higher voltages." We are building a system to comprehensively support the development of e-Axles as they continue to reach higher speeds.

Moving forward, we will continue to expand our evaluation and service offerings to include different cooling methods and target areas, contributing to further efficiency and reliability of e-Axles.