液压机械无级传动全功率换段过程排量比调节模型  

Model of regulating displacement ratio in full power shifting process of hydro-mechanical variable transmission

作　　者：杨树军[1] 张曼 曾盼文 张寅君 张璐 田霖 Yang Shujun;Zhang Man;Zeng Panwen;Zhang Yinjun;Zhang Lu;Tian Lin(College of Vehicles and Energy, Yanshan University, Qinhuangdao 066004, China;Jianglu Mechanical and Electrical Co., Ltd, Xiangtan 411199, China)

机构地区：[1]燕山大学车辆与能源学院,秦皇岛066004 [2]江麓机电集团有限公司,湘潭411199

出　　处：《农业工程学报》2019年第13期64-73,共10页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然基金面上项目（51675462,51175449）;河北省高校科技支撑项目（ZD2016012）

摘　　要：为了解决液压机械换段过程中存在的转速波动和瞬时动力中断等问题,该文以两离合器结合重叠的五阶段全功率动力换段方法为基础,分析了液压机械全功率换段过程变排量液压元件排量比调节规律。以某等差两段式液压机械为研究对象,建立了液压机械全功率换段过程变排量液压元件排量比调节模型,通过仿真分析和全功率换段过程试验,获得了换段过程液压回路压力从当前段到目标段随排量比变化的动态响应过程。结果表明,排量比变化量的仿真与试验结果基本一致,最大偏差为8.93%,验证了模型的正确性;排量比调节模型能够根据当前段状态参量和目标段压力预测出目标段排量值;阶跃排量比调节规律能有效缩短液压回路建压时间,建压时间为0.93 s,压力波动量较小,为0.64 MPa;按阶跃调节排量比至目标值,能在换段过程完成液压回路高低压侧压力平稳互换,换段前后输出转速几乎无波动、转矩连续传递。经增速机后的输出转矩为100和150N·m时,换段时间分别为1.00和1.10s,该转矩的最大波动量分别为6.80和6.84N·m,换段过程中功率连续且平稳传递。研究结果可为实现液压机械无级传动全功率换段控制及后续研究提供参考。Hydro-mechanical variable transmission (HMT) is a kind of double power flow transmission system constituted by hydraulic branch and mechanical branch in parallel. HMT has the ability to realize high-power CVT and high transmission efficiency, and is suitable for high-power automobiles. In general power shift process, there are load reversal in hydraulic transmission unit, power flow reversal in hydraulic branch, and function interchange in hydraulic components. At the same time, the speed of fixed displacement hydraulic component changes abruptly, and there is a short time power interruption. To solve the problems of speed fluctuation and power interruption in power shift, based on the five-stage full power shift method by overlapping the double clutches, the displacement regulating law of variable displacement hydraulic component is studied in this paper. An arithmetic type two-range HMT is taken as the research object, and the pressure responses to different displacement regulation are analyzed. The torque characteristic equation in full power shift is derived. The cavity model of closed hydraulic circuit is established, in which the closed hydraulic circuit is simplified to two cavities. Considering the influence of the volumetric efficiency of the hydraulic transmission unit, the mathematical model of the displacement ratio regulation of variable displacement hydraulic component is derived. The step change and linear change of displacement ratio are adopted respectively, and the pressure response is obtained by simulation. The results show that the regulation law of displacement ratio has a great influence on the time of pressure building-up and pressure fluctuation. The step change of displacement ratio can effectively reduce the time of pressure building-up, and there is no obvious increase of pressure fluctuation compared with that of the linear change. The power shift time is 0.93 s and pressure fluctuation is 0.64 MPa. In order to reduce the power shift time, the step change of displacement ratio could b

关 键 词：液压机械 传动 控制 无级传动 全功率换段 排量调节 

分 类 号：U463.2[机械工程—车辆工程]