Analysis of squeeze process and engagement characteristics of wet friction clutch
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摘要:
针对湿式摩擦离合器接合过程中的挤压机理及微凸体接触问题,综合考虑摩擦片表面油槽结构,材料渗透性等因素,根据修正雷诺方程和K⁃E(Kogut⁃Etsion)接触模型,对湿式摩擦离合器的挤压过程中的动压承载力、微凸体承载力以及转矩转速变化等建模分析,并采用有限差分法对修正雷诺方程求解,对挤压过程中的油膜压缩速度、油膜厚度变化率和片间承载力等挤压特性和转速、转矩等接合特性展开了仿真分析。并采用SAE#2试验机进行了相关试验获得了转速、转矩、压力、摩擦因数等数据,与仿真分析进行了对比。结果表明:湿式摩擦离合器接合过程可分为3个阶段,通常会在1 s内完成,在0.02 s左右开始从挤压阶段经压紧阶段在0.03 s左右过渡到全微凸体接触阶段,试验与理论分析结果一致。
Abstract:In view of the extrusion mechanism and micro⁃convex contact problem during the engagement process of the wet friction clutch,the oil groove structure on the surface of the friction plate,the material permeability and other factors were comprehensively considered;according to the modified Reynolds equation and the K⁃E (Kogut⁃Etsion) contact model,the wet friction clutch was squeezed in the process,the dynamic pressure bearing capacity,the bearing capacity of the micro convex body and the torque and speed change of the model were analyzed,and the modified Reynolds equation was solved by the finite difference method.For the extrusion characteristics such as the oil film compression speed,the oil film thickness change rate and the load bearing,and the engagement characteristics such as speed and torque,simulation analysis was carried out.And SAE#2 testing machine was used to carry out relevant tests to obtain data such as speed,torque,pressure,friction factor,etc.,and compare them with the simulation analysis.Studies showed that the wet friction clutch engagement process can be divided into three stages,which were usually completed within 1 s,starting at about 0.02 s and transitioning from the extrusion stage to the full micro⁃convex contact stage at about 0.03 s after the compaction stage.The test results were consistent with the theoretical analysis results.
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Key words:
- wet clutch /
- Reynolds equation /
- squeeze process /
- oil film squeeze speed /
- rotation speed torque
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表 1 摩擦副结构参数与试验条件
Table 1. Friction pair structure parameters and test conditions
类别 参数 数值 试验参数 制动转速 /(r/min) 6 000 系统转动惯量J/ 0.343 9 初始油膜厚度hi/m 0.000 1 最大加载压力pmax/MPa 1.0 润滑油参数 黏度 / 0.012 密度 /(kg/m3) 870 几何特征 摩擦副内径ro/mm 73 摩擦副外径ri/mm 59 油槽深度hg/mm 0.3 油槽宽度wg/mm 1 油槽基圆半径Rb/mm 50 油槽轨迹半径Rg/mm 30 油槽阵列数量Ng 55 材料特性 联合表面粗糙度方均根 /10-6 m 8.4 微凸体分布密度 /107 m-2 7 微凸体半径R/10-4 m 8 衬片材料渗透性 /10-13 m2 8 摩擦片泊松比 0.3 钢片泊松比 0.4 摩擦片弹性模量E1/GPa 10.59 钢片弹性模量E2/GPa 206 较软材料硬度Ha/GPa 2.8 -
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