A Development of Spindle Drive Power Trunk Lid System with Optimizing Operation Noise

The power trunk lid system is a device that automatically opens and closes the trunk lid by motor, for the purpose to improve user’s convenience. This technology was applied only to high-end large cars such as Equus and Genesis. But as preference for high convenience features increases, the scope of application is gradually expanding to semi-large and mid-sized cars. Therefore, the necessity of securing profitability through cost reduction was emerged, and it made us to develop the power trunk lid system by spindle drives. Compared to the conventional swing arm drive type, the spindle drive type may achieve cost savings, lightness and easy of assembly by optimizing the required motor specifications. However, since it uses a planetary gear with high gear ratio and the high rotation speed of the motor, operating noise is relatively large. To reduce the operating noise of the system when we first applied the new system to K8 model, we verified the noise is structure born noise and identified which path the vibration spreads, and also measured the frequency response function of correlated structure through impact hammer test. We then compared the function with the excitation frequency of the drive unit to optimize the rotational speed of the motor. In this paper, we would like to introduce the experience of performing the above process and the overall considerations of developing the spindle drive type power trunk lid system.