基于虚拟样机技术的液压液力复合转向机构的优化匹配研究

满足履带车辆在恶劣路面实现原地转向是转向系统设计的重要指标之一.目前,我国履带车辆普遍采用液压机械双功率流的无级转向系统,为满足大吨位车辆原地转向要求,必须匹配大排量的液压泵-马达或提高液压泵-马达的系统压力.为克服这些不足,提出液压液力复合转向工作机构.首先分析了液压液力复合转向机构的工作原理,确定了液力偶合器的原始特性.然后,以某车的综合传动系统为研究基础,通过引入液力偶合器构成液压液力复合转向机构,并在ADAMS/View环境中建立了相应的虚拟样机模型.以此模型为蓝本,确定了4个设计变量,通过分析,偶合器的有效直径和动力输入到液力偶合器泵轮的传动比为关键变量,并进行变量的敏度分析.最后,建立了优化约束条件和优化目标,利用ADAMS的DOE(Design of Experiment)功能进行了优化设计的仿真分析,确定了偶合器的有效直径和传动比,并进行了仿真实验.仿真表明,设计的液压液力复合转向机构可满足车辆在恶劣路面原地转向的要求,同时显著降低了液压泵-马达的排量,为低排量泵-马达实现大吨位车辆的转向性能提供了依据.

Research on Optimization and Match of Hydrodynamic and Hydrostatic Combined Steering Mechanism Based on Virtual Prototype Technology

The requirement for track vehicles to realize pivot-turning on rigorous land surface is one of the important indexes in steering system design. A hydro-mechanical stepless steering system with dual power flows are commonly adopted on domestic track vehicles. In order to meet the requirements in pivot-turning of large tonnage vehicles, hydraulic pump-motor with large displacement must be equipped or system pressure of the pump-motor must be increased. A hydrodynamic and hydrostatic combined steering mechanism is suggested to overcome these shortcomings. Firstly, the mechanism principle is analyzed and the natural characteristics of a hydraulic coupler are determined. Then, taking the comprehensive drive system on a vehicle as a research basis, a hydrodynamic and hydrostatic combined steering mechanism is structured through introducing a hydraulic coupler and a related virtual prototype model is set up in ADAMS/View environment. Taking the model as the original, four design variables are determined. Through analysis, the key variables are the effective diameter of hydraulic coupler and the drive ratio of power input to impellor of the coupler and their sensitivities are analyzed. Lastly, boundary conditions for optimization and optimal targets are established and simulation analysis of optimal design is carried out with DOE function in ADAMS. Effective diameter and transmission ratio of the coupler are obtained. The simulation shows that the developed steering mechanism could satisfy vehicles to make pivot-turning on rough ground and at the same time the displacement of hydraulic pump-motor is significantly reduced, which provides a basis for large tonnage vehicles to realize their steering performance with low displacement pump-motor.