含沟槽湿式离合器接合特性数值与试验研究

为了研究工况参数对湿式离合器接合特性的影响规律，基于Navier-Stokes方程、KE粗糙接触理论和传热理论，针对含沟槽湿式离合器建立接合特性综合数值模型. 利用自主研制的离合器试验装置，针对接合压力、润滑油（ATF）温度、相对转速、渗透性和沟槽等影响因素进行正交试验. 结果表明，接合压力不仅影响接合时间且对扭矩有影响，压盘接触瞬间的扭矩抖动取决于接合压力稳定性，接合完成瞬间的扭矩抖动是由动静摩擦系数差异造成的；润滑油温升高，黏度降低使粗糙峰接触延迟造成接合时间增长，接合扭矩减小；转速越高，接合时间越长；渗透性越高，油膜厚度下降越快，接合响应速度越快；沟槽宽度越大，接合扭矩的幅值越小，接合时间越长. 初始油膜厚度越大，接合初始阶段的油膜剪切扭矩越小.

Simulation and experimental study of engagement process with groove consideration

A comprehensive numerical model was established based on the Navier-Stokes equations, KE rough contact mechanics and heat transfer theory with grooves consideration in order to analyze the effect of the operating conditions on the engagement behavior of wet clutches. The orthogonal experiments were conducted to analyze the effect of the operating parameters such as applied pressure, the temperature of automatic transmission fluid (ATF), the relative rotation speed, the permeability and the grooves based on the independently developed experimental setup. Results show that the applied pressure not only affects the engagement time, but also the engagement torque. The first torque judder that appears at the moment of the piston touching the plates depends on the stability of the applied pressure. The second torque judder that appears at the end of the engagement process is caused by the difference of dynamic and static friction coefficient. The increase of the temperature of ATF makes the dynamic viscosity decrease, which delays the rough contact and engagement process. The hydraulic torque decreases accordingly. The higher the relative rotation speed is, the longer the engagement time is. The higher the permeability of the friction material is, the faster the decrease of the film thickness and the engagement response is. The larger the groove width is, the smaller the engagement torque is, the longer the engagement time is. The larger the initial film thickness is, the smaller the shearing torque is.