拖拉机液压机械无级传动系统液压泵马达全工况效率模型研究  

Efficiency Model of Hydraulic Pump-Motor for Tractor Hydro-Mechanical CVT Under All Operating Conditions

作　　者：程旭[1] 彭增雄[1] 荆崇波[1] CHENG Xu;PENG Zengxiong;JING Chongbo(School of Mechanical Engineering,Beijing Institute of Technology,Bejing 100081,China)

机构地区：[1]北京理工大学机械车辆学院,北京100081

出　　处：《北京理工大学学报》2025年第2期154-164,共11页Transactions of Beijing Institute of Technology

基　　金：装发部慧眼行动项目(628020209);国防科工局VTDP项目。

摘　　要：未来拖拉机传动系统发展的主流技术之一是液压机械无级传动技术(CVT),其核心部件液压泵马达的效率特性对CVT总体效率和动力学特性的研究至关重要.针对目前液压泵马达效率经验模型研究中存在的效率预测准确性不高、缺少内部摩擦副功率损耗分析以及有限元效率模型计算时间长等问题,提出了一种基于损失机理的半经验全工况效率模型,满足快速准确的液压泵马达效率评估.根据柱塞泵系统参数的非线性变化规律,建立功率损失预测的半经验模型,利用试验数据对复合参数进行识别,推导得到完整的液压泵马达效率模型.试验数据表明,半经验全工况模型的平均相对误差为6.36%.分析仿真结果可知,液压泵马达效率在高、低压差区域分别主要受容积和机械损失影响,在极限工况下效率难以提升主要由流量泄漏、可压缩容积损失和库伦摩擦损失导致.保持液压泵马达在中高排量区域运行、避免低压高速工况有利于提升液压泵马达效率,进而提升CVT整机传动效率.Hydro-mechanical continuously variable transmission(CVT)is one of the mainstream technologies for the future development of tractor transmission systems,and the efficiency characteristics of the hydraulic pump-motor are crucial for the dynamic performance of CVT.To solve the existing problems in predicting the efficiency of hydraulic pump-motors,including in defect of the analysis on the power loss between friction parts and taking much calculation time with the finite element efficiency model,a semi-empirical efficiency model was proposed based on loss mechanism for all operating conditions to evaluate exactly the efficiency of hydraulic pump-motor.Considering the nonlinear changing regularity of system parameter,some functions of the model were designed to predict the power loss,to fit the compound system parameters based on experimental data,finally to obtain a complete efficiency model for the hydraulic pump-motor.Experimental data shows that the average relative error of the model is 6.36%.The volumetric loss in high-pressure differential regions and the mechanical loss in low-pressure differential regions are the main influence on the pump-motor efficiency.Causing the difficulty in improving efficiency of hydraulic pump-motor under margin working conditions,the main reasons are the flow leakage,compressible volumetric loss and Coulomb friction loss.It is the beneficial for improving pump-motor efficiency and enhancing the overall transmission efficiency of CVT to operate the pumpmotor in medium to high displacement regions and avoid low-pressure and high-speed conditions.

关 键 词：液压机械 无级传动系统 液压泵马达 效率模型 

分 类 号：TH137[机械工程—机械制造及自动化]