Airgapless PMSM With Diamond Like Carbon Coating Technology for Torque Improvement

The goal of this study is to investigate a radial type permanent magnet synchronous motor without airgap using diamond like carbon coating (DLC) technology to maximize the torque and verify the possibility of applying DLC to motor. Since existing motor technologies have limitations in improving torque, a material is introduced which can enhance motor power. The DLC coating used in automotive combustion engines allows the engine to perform well even at very high temperatures and under strong friction conditions. Also, auto transmission oil, which is used as cooling oil for HEV/EV traction motors, was used to minimize the friction between the rotor and the stator and to cool the rotor and stator. Also, effectiveness of drag force and temperature by friction were investigated. As a result, even if the rotor and stator collide due to the vibration generated in the airgap between bearing cap and ball, the motor can rotate without any problems, and the motor torque greatly increases. After the motor rotates at 5,000 r/min, the DLC coating adopted to electric motor is verified.