Hydro-Mechanical Continuously Variable Transmission System Simulation And Research On Quality DF Shifting Process

Hydraulic mechanical stepless Transmission (HMCVT) transmits both the hydraulic power and mechanical power. HMCVT has the advantages of high efficiency and large transmission power. HMCVT is one of the domestic and foreign advanced model transmission.The combination and separation of clutch needs certain time. In this process,factors such as load caused speed drop in period of before and after the output shaft.If you can’t get reasonable control for this rate drop gearbox, it will be a kind of injury for clutch and transmission.At the same time,it also can affect the ride comfort and handling of corresponding vehicle.We developed a hydraulic mechanical stepless transmission which is suitable for high-power road vehicle, and set up the experimental platform. This topic is based on the hydraulic mechanical stepless transmission test bench. In the binding process of wet clutch the oil pressure characteristics were studied, and the quality of exchange period was studied by means of the orthogonal experiment. At the same time the simulation model was set up by Matlab/Simulink.The simulation analysis was carried out on the part of the research content. This article main research content is as follows:1、This paper introduces the working principle of HMCVT. Established the theory model of the output rotating speed and output torque of the theoretical model.2、Simplified model using equivalent rotation inertia moment of inertia of the transmission parts, makes the model more efficient. Useing Matlab/Simulink to model the HMCVT simulation model. This model can be divided into six modules,as engine module, hydraulic pump, motor drive module, mechanical transmission module, control module, load module, output module. And illustrated the function and the main components of the six modules. Finally combining with the experimental and theoretical data, the simulation results are good.Main research conclusion is as follows:Speed regulating valve flow is greater than3L/min the oil filled and the clutch booster short time, speed regulating valve flow between1～3L/min for oil filled time and good regulation performance of clutch booster. Main hydraulic oil pressure at about4～5Mpa oil charge time is relatively shorter. Rise time along with the pressure variation is not obvious. When the speed regulating valve flow is greater than3L/min, booster oil pressure curve slope is larger and more stable. As the pressure increases, oil pressure change rate is getting higher.3、Studied the wet clutch hydraulic characteristics on the binding process. Established the dynamic models for each stage. To analyze the data intuitively, we fit the experimental data with curved surfacere spectively for the clutch oil charge time, rise time, oil change speed of booster period. Made analysis for the hydraulic characteristics of oil filled stage.4、Analyzed the quality of orthogonal experiment results in the exchange period. Main conclusions are as follows:in order to improve quality, finally select A1B3as the optimal level combination, which is the main oil oil pressure of4Mpa, speed regulating valve flow take5L/min.5、Using the simulation model on the part of the test was unable to complete the analysis of the simulation analysis. Concluded with the volumetric efficiency of pump-motor system is promoted, in addition to the friction between the transmission and pump motor system of the monitoring values are optimized; As for combination of clutch ahead of time, in period of quality was improved.