干式离合器摩擦片温度分布
Temperature distribution of friction plate for dry clutch

针对干式离合器在汽车传动过程中产生的热失效问题,研究了摩擦片的温度分布。基于干式离合器的工作原理,建立了包括主从动部分、摩擦片压力和摩擦因数在内的离合器接合模型。结合轴向弹性作用元件特性和分离轴承与膜片弹簧接触面旋转而与分离拨叉接触面不旋转的结构特点,将环状压力传感器布置在与分离拨叉的接触面,估计了实时离合器摩擦片压力。通过干式离合器试验台和摩擦因数模型,求解了在连续工作400 s的摩擦传递转矩和滑摩功,计算了环境吸热、摩擦生热与对流散热3种边界的摩擦片热负荷,分析了瞬时冲击接合与频繁接合2种工况下的摩擦片热变形。分析结果表明:在离合器瞬时冲击2 s的接合工况下,摩擦片热变形最大,可达0.188 mm,变形后摩擦片的温度显著升高; 在频繁接合工况下,边界2滑摩热负荷对离合器接合前200 s的摩擦片温度分布起主要作用,边界2、3对流热同时对200 s后的温度分布起重要作用。
In view of the thermal failure of dry clutch in automobile transmission process, the temperature distribution of friction plate was studied. Based on the working principle of dry clutch, the clutch engagement model including its active and driven parts, friction surface pressure and friction coefficient was established. Combined with axial elastic element characteristics and release bearing structure characteristics that the contact surface of diaphragm spring rotates and the contact surface of separated forked plectrum does not rotate, an annular pressure sensor was fixed on the contact surface of separated forked plectrum, and the real-time friction pressure of clutch was estimated. Based on the dry clutch test bench and the friction coefficient model of dry clutch, the friction transfer torque and slipping friction power on the continuous operation of 400 s were estimated. The heat load of friction surface of dry clutch was calculated based on three kinds of boundaries including heat absorption from environment, heat producing by friction, and heat dissipation in convection. The thermal distortions of friction plate in 2 conditions were analyzed, including instantaneous impact engagement and frequent engagement. Analysis result shows that in the condition that the time instantaneous impact engagement is 2 s, the maximum heat distortion of friction plate can reach 0.188 mm, and the temperature of friction plate rises obviously. In frequent engagement condition, the temperature distribution of friction plate mainly depends on the second boundary of slipping friction heat load before 200 s of clutch engagement, and it depends on the second and the third boundary of convective heat after 200 s of clutch engagement. 11 figs, 26 refs