关键词: 螺栓松动；预紧力；安装扭矩；屈服强度

Abstract: Bolt looseness is a difficult problem in automobile reliability, which often troubles automobile designers. In this paper, the pre-tightening force, mounting torque and contact surface yield strength of the bolts are calculated and checked by technical cooperation with fastener manufacturers. According to the problems of the contact surface of the suspension bracket, such as the risk of yield collapse and the lack of the pre-tightening force of the bolts, the corresponding improvement schemes are made respectively, and the range of the mounting torque of the fastening bolt is finally determined, to meet the requirements of mounting rubber pad pre-tightening force. The mounting torque determined by the calculation method in this paper is fixed, and after fastener lateral vibration test and cross-country road test, the mounting rubber pad fastening bolts of powertrain mount do not loose again, it can be seen that the bolt loosening calculation check and improvement program is effective. In this paper, the pre-tightening force, mounting torque and the strength of the contact surface of the bolts are calculated and improved, which provides a very good solution to the problem of automotive bolt loose ideas and methods.

Key words: Bolt looseness; Pre-tightening force; Mounting torque; Yield strength