Study On Controlling Method Of Metal Belt Continuously Variable Transmission (CVT) In Clamping Force Aiming Slip Rate

The Metal Belt Continuously Variable Transmission is a type of ideal transmission for passenger cars. Compare with other Transmissions, it has many advantages, such as the function is good ,the structure is simple and the price is low ,etc. But at present the CVT that was equipt can not economize energy as it is in theory . The reason is the efficiency of CVT is not enough . Improving the efficiency of CVT has been a very obligatory problem and studying hard problem for pursuers and laboratories .In this thesis I consult the investigative progeny of precursors and analyse the reason of the torque loss in CVT , And advance control method of clamp force base on aiming slip rate . And design the project of measuring slip rate and realize this project. After theseI design the project of control method of clamp force base on aiming slip rate and realize this project.(1) Continuously Variable Transmission(CVT)has a long history. From vehicle exists, it become the popular. In the range of designment, Metal Belt continuously variable transmission speed ratio can be continuously changed, make engine at the optimum condition, prolong its service life, improve the vehicle efficiency, power, and comfortability.(2) For analyzing the relationships between clamp force and torque loss of CVT , at first I analyze the three reasons of the torque loss of CVT and summarize each math formula . At the second I summarize the math formula of clamp force and found the MATLAB-model of clamp force . Then analyze the relationships between ratio and torque . At last base on the analyzing ahead I found the MATLAB-model of torque loss and clamp force and analyze the relationships between torque loss with clamp force .(3) Summarizing the math formula of the displacement of primary pulley and ratio . And Summarizing the math formula of slip rate .Then I design the experiment-project of measuring slip rate andselect the equipment needed . Then realize the project on test-bed.(4)Base on the investigative result of precursors about the relationship of slip rate and efficiency of CVT , I bring forward the control method of clamp force base on aiming slip rate and establish the control strategy of clamp force base on aiming slip rate . Combining the condition of test-bed make certain the aim of clamp force control is slip rate is 0.02.And through control the clamp force make the slip rate is always 0.02.(5) For the needed of clamp control I choose the means of measuring the rotate speed to make the rotate speed become more exactitude .On test-bed I experiment the control of clamp force of simulate vehicle calm drive , speedup drive and upgrade drive .And experiment the control of clamp force with ratio control at the same time. Then deal with the result of experimentation and analyze the result. The result shows that the clamp force controller can meet the needed of the slip rate -0.02 and the controller has good control result.This thesis carried out the CVT clamp force control base on the aiming slip rate .This control method has not appear before interiorly. The result shows that this kind of control method is feasible.