| 摘要 |
PURPOSE: A frequent operation of an end clutch valve is prevented in case of having a large pressure amplitude of an end clutch control pressure. Therefore, a line pressure variation and a control pressure variation are prevented to stabilize a control pressure of the end clutch in 4-2 transmission shifting. CONSTITUTION: In a hydraulic pressure control system of an automatic transmission, a control switch valve(21) controls a passage by a solenoid valve. An end clutch valve(19) is controlled by a hydraulic pressure supplied to an end clutch through the control switch valve, and supplies the hydraulic pressure from a shift control valve to the end clutch through the control switch valve(21) or discharges the supplied hydraulic pressure. An end clutch valve control member operates the end clutch valve without disorder or delaying pressure forming in transmissions except 4-2 transmission, and prevents switching repetition of the end clutch valve(19) in 4-2 transmission even in case of large pressure amplitude of an end clutch control pressure. Therefore, a large variation of a line pressure and the end clutch control pressure are prevented.
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