| The CVT in form of metal tape, as a new transmission of mechanical friction type with preventable intermediate, has a lot of advantages, such as simple structure, strong carrying capacity, large range of speed changing, small volume, high efficiency, little noise, etc. However, as a result of the specific way of speed changing of this type of transmission, the axial offsetting of metal tape becomes an inevitable consequence. This kind of offsetting will lead to the mutual slippage and additional wear between belts and belt wheels, thus, consumes extra energy, which will directly affect the performance and efficiency of the transmitting. When the offsetting goes too far, the metal belt and the belt wheel would wear so seriously that CVT could not work as usual, which, consequently, must be got rid of.This essay is to analyse the working principle of CVT in form of metal tape and the mechanism of the offsetting, based on which the electron-hydraulic pressure method is adopted to restrain the offsetting of metal tape for EQ6480 automobile CVT and at the same time to redesign the transmission ECU with SCM system of MC9S12DP256 of Freescale, and to adjust the speed ratio of transmission for controlling the offsetting. This system is mainly composed of SCM system, catching circuit of pulse input, analog quantity input circuit, I/Q input circuit, PWM electromagnetically- operated- valve -driven circuit, CAN interface, power supply and communication, etc.Magnetoelectricity rev transducer is chosen to test the rotate speed of the engine , of the input and output of CVT and to test the position of the transmission belt. As to the design of inside CAN communication network three scales of different speeds for CAN communication network are set as high, media and low, considering the complicated situations of automobile movements and the requirements of real time for each pitch point.The pitch points which require strict real time will constitute high... |
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