在低速大扭矩内曲线液压马达工作转速朝着极低转速（最低可达0.2 r/min）发展时，其核心摩擦副之一的滚柱-柱塞副由于低转速时难以建立润滑油膜而极易导致摩擦副磨损失效。因此，在滚柱-柱塞副之间通常设置钢背-铜粉-自润滑材料的三层轴瓦结构，以提高摩擦副的低速润滑能力。但内曲线液压马达通常需要承受较大负载，如何设计高承载能力的三层复合轴瓦成为内曲线液压马达设计的难点。三层复合轴瓦各层材料的厚度分配会直接影响轴瓦受载下的最大应力，进而影响内曲线液压马达的承载能力和使用寿命。为探究三层轴瓦各层厚度对复合轴瓦整体承载能力的影响规律，文中对三层复合轴瓦进行受力分析，得到了三层材料厚度与自润滑层最大等效应力的映射规律，提出了一种适用于内曲线液压马达滚柱-柱塞副的低应力三层复合自润滑轴瓦厚度分配方案，并针对一款最大工作压力为31.5 MPa的内曲线液压马达设计了三层轴瓦厚度分配方案（其自润滑层厚度为0.2 mm、铜粉层厚度为0.3 mm、钢背层厚度为1.0 mm），将采用该方案的三层复合轴瓦安装在液压马达上进行了马达性能测试。试验结果表明，该厚度分配下轴瓦承载能力满足内曲线液压马达最大工作压力的要求。

When the working speed of the low-speed high-torque cam lobe hydraulic motor is developing towards an extremely low speed (up to 0.2 r/min), one of its core friction pairs, the roller-piston pair, is difficult to establish a hydrodynamic lubricating oil film at low speeds, leading to wear fail of the friction pair. Therefore, a three-layer bearing bush structure of steel back-copper powder-self-lubricating material was usually arranged between the roller-piston pair to improve the lubrication ability of friction pair at low speed. However, the cam lobe motors usually need to withstand large loads, and how to design three-layer bearing with high bearing capacity has become a challenge in the design of cam lobe hydraulic motors. The thickness distribution of each layer of the three-layer bearing directly affects the maximum stress of the bearing under load, and then affects the bearing capacity and service life of the cam lobe hydraulic motor. In order to explore the effect of the thickness of each layer of the three-layer bearing bush on the overall bearing capacity of the bearing bush, this paper carried out the force analysis of the three-layer bearing bush, and obtained the mapping law between the thickness of the three-layer material and the maximum von Mises stress of the self-lubricating layer. And this paper also proposed a low-stress three-layer self-lubricating bearing bush thickness distribution scheme suitable for the roller-piston pair of cam lobe motors and designed a three-layer bearing thickness distribution scheme (the self-lubricating layer thickness was 0.2 mm, the copper powder layer thickness was 0.3 mm, and the steel back layer thickness was 1.0 mm) for an cam lobe hydraulic motor with a maximum working pressure of 31.5 MPa.The three-layer bearing using this scheme was installed on the hydraulic motor for motor performance testing. The test results show that the bearing capacity of the bearing under the thickness distribution can meet the requirements of the maximum working pressure of the cam lobe motor.