车用湿式多片离合器油液冷却研究

Study on cooling model of the vehicle multidisc wet clutch

湿式多片离合器需要润滑冷却来防止高转速大扭矩引起的高温烧蚀。工程实际中,多通过经验来确定需求流量值,为了从理论上确定冷却所需合适的润滑油流量,根据热平衡理论建立了湿式多片离合器的油液冷却模型,推导了钢片随时间的平均温升和油液出口油温变化规律,研究了离合器对流换热系数和热流分配的影响,并通过计算和实验,得到润滑流量增加到一定程度时冷却效果不再显著增加的规律,并指出对于所研究的湿式多片离合器,合适的供油量为单副（1.5~2.0）L/min,为工程应用中供油量选择提供理论指导。

High speed and large torque cause the multidisc wet clutch ablate under high-temperature,so effective cooling is needed. For the engineering practice,the need of flow is determined generally based on experience. To get the proper flow value for cooling theoretically,a cooling model for multidisc wet clutch was established by the heat balance equation. The average temperature change of separator disc and export oil temperature was derived. During calculation,clutch oil leakage,convective coefficient and heat distribution were considered. The results of numerical calculation and experiment indicated that the oil flow decreased the separate disk temperature,but this effect was limited when the flow increased to a degree and for the studied multidisc wet clutch,the suitable flow was（ 1. 5 ～ 2. 0） L / min per pair,providing theoretical guidance for engineering application.