| 摘要 |
A hydraulic control system of 8-shift automatic transmission for vehicles is provided to supply the control pressure of the pressure control valve controlled by the ratio control solenoid valve as a frictional element. A hydraulic control system of 8-shift automatic transmission for vehicles comprises the first, the second, the third clutch control sections(F,G,H), the first brake control unit(I), the fourth clutch, and the second brake control unit(J). The first clutch control section is directly provided with the control pressure of the pressure control valve(18) in which the first clutch is controlled by the first ratio control solenoid valve(VFS1). The second clutch control section receives the control pressure of the second pressure control valve(22) through the first safe valve(26). The third clutch control section is directly provided with the control pressure of the third pressure control valve(28) in which the third clutch is controlled by the third ratio control solenoid valve(VFS3). The first brake control unit is directly provided with the control pressure of the fourth pressure control valve(32) in which the first brake is controlled by the fourth ratio control solenoid valve(VFS4). The fourth clutch and the second brake control unit share the control pressure of the fifth pressure control valve(36) in which the fourth clutch and the second brake are controlled by the fifth ratio control solenoid valve(VFS5).
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