Abstract:

In order to evaluate the performances of an automobile clutch system, a testing platform of clutch system was established. The mechanisms of clutch system, which were simulated to install on a car, were tested with this platform and then the characteristic curve of pedal and the relative experimental data were obtained. It is found that pedal max-force is too large, the pre-tightening force is too small and pedal down force is too small. To solve these problems, a mechanics model of the clutch operating mechanisms was built and the relative factors which affected the performances of the clutch were analyzed. From the view of practical engineering, optimizing structure parameters of torsional spring were proposed to change pedal mechanical characteristics and ensure performance requirements of the clutch system. Motion state of torsional spring was analyzed and its mechanics model was built. Installation angle of torsional spring was optimized based on achieving maximum power effect. According to the design constraints of the clutch and the objective function of the maximizing fatigue safety factor of torsional spring, the torsional spring's wire diameter, mean diameter, arm length and number of turns were optimized. The improved torsional spring was installed again in the pedal mechanism, and the optimization scheme was verified to be feasible and rational by the testing platform.

Key words: clutch, operating mechanism, pedal, torsional spring, mechanics modeling, parameter optimization

摘要： 为了评估某品牌汽车离合器性能，构建了离合器系统台架测试平台，通过模拟离合器系统在整车上的安装状态进行测试，得到踏板特性曲线及相关试验数据。针对台架测试中出现最大踏板力过大、预紧力过小、踏板下降力过小等问题，对离合器操纵机构进行力学建模，并分析影响离合器性能的相关因素。从工程实用的角度提出优化扭转弹簧的结构参数来改变踏板力学特性，保证离合器系统满足性能要求。对扭转弹簧进行运动分析并建立其力学模型，以扭转弹簧能够达到最大助力效果为原则，优化扭转弹簧安装角度；根据离合器设计约束条件，以扭转弹簧疲劳安全系数最大为目标函数，优化弹簧线径、中径、臂长和圈数等参数。将改进后的扭转弹簧重新装入踏板总成，通过测试平台验证了优化方案的可行性和合理性。

关键词: 离合器, 操纵机构, 踏板, 扭转弹簧, 力学建模, 参数优化