Deformation pre-compensated optimization design of cam ring for low pulsation hydraulic motors

Abstract

Cam-lobe radial-piston hydraulic motors are widely used in large machinery due to their excellent capability to withstand high loading at low speed. However, the line contact between the roller and cam ring generates elastic deformation of the cam ring under high loading, leading to obvious speed and torque pulsations and even the detrimental crawl problem of hydraulic motors. To address this issue, we propose a deformation pre-compensated optimization design approach to compensate for the cam ring deformation in advance, thereby eliminating the influence of cam ring deformation on the hydraulic motor’s pulsation. In this approach, the design process is divided into two steps: first, the overall profile of the cam ring is optimized based on the calculated elastic deformation; second, the local profile of cam ring is further optimized until the hydraulic motor’s pulsations no longer reduce. Finally, a case study is carried out to verify the effectiveness of this approach. The result indicates the pulsation rate of a deformation pre-compensated cam ring is 40% lower than that of an uncompensated one. This study offers an easy and feasible way to design an optimized cam ring profile for low pulsation hydraulic motors. 目的 内曲线液压马达在重载工况下凸轮环与滚子接触产生的弹性变形, 改变了预设的运行轨迹, 使得马达产生较大 的转速转矩脉动。本文提出一种凸轮环变形预补偿的优化设计方法, 在设计阶段耦合弹性变形的影响, 以降低 马达在实际工作时的脉动, 从而提高马达的稳定性。 创新点 1. 通过赫兹接触理论和马达结构的受力分析, 建立凸轮环弹性变形非均匀分布的计算方法; 2. 建立凸轮环弹性 变形预补偿的设计方法, 并通过实验进行验证。 方法 1. 通过理论推导建立凸轮环非均匀弹性变形与工作压力之间的直接关系, 基于此提出凸轮环弹性变形预补偿的 设计方法, 并给出完整的流程与计算方法。2. 通过仿真模拟, 对凸轮环变形计算进行验证, 初步证明所提方法 的正确性。3. 通过实验验证, 对在不同工况下, 马达的脉动率进行分析, 验证所提方法的有效性。 结论 1. 提出凸轮环变形预补偿优化设计方法, 包括初始的整体补偿和二次局部补偿。2. 在对马达进行详细运动学和 受力分析的基础上, 推导出凸轮环变形的计算过程, 并用有限元仿真方法进行实例验证。3. 脉动降低率随着工 作压力的增加而增加, 并且在45 MPa 工作压力下可以实现40%的高脉动降低率。