| 摘要 |
Disclosed is a system for controlling hydraulic pressure in an automatic four-speed transmission, which comprises an oil pump (46) for producing hydraulic pressure by using engine power, a regulator valve (V9) for regulating the hydraulic pressure produced by the oil pump according to the phases of a manual valve (V1) and a pressure control solenoid valve (S5), the phases being changed according to the vehicle speed stages, the manual valve changing the phase by means of a shift lever, a shift control valve (V2) for supplying the hydraulic pressure from the manual valve to a plurality of shift valves according to the output signals of the first and second shift control solenoid valves (S1, S2), the shift valves including a first and second shift valves being controlled by the hydraulic pressure applied via the shift control valve and the pressure control valve (V5), a pressure control valve for supplying the hydraulic pressure from the manual valve to the shift valves in the speed stages other then the first speed stage under the control of the hydraulic pressure applied through a reducing valve (V8), a second to third/fourth to third shift valve (V6) for passing or blocking the hydraulic pressure applied via the first and second shift valves so as to work a front clutch (41) and to release a kickdown brake (45), and a rear clutch release valve (V7) for passing or blocking the hydraulic pressure applied to a rear clutch (42) via the manual valve under the control of the control pressure applied via the reducing valve according to the control signal of the gearshift control. |
