Shift from 2nd speed to 3rd speed Fast hydraulic circuit

摘要

The present invention relates to a hydraulic control device for a 4-speed automatic transmission, and in particular, in the case of a shift from a second speed to a third speed, the shifting time is reduced to improve the shift quality and prevent the increase in the pressure of the existing front clutch To an improvement of a 2 to 3 shift valve which is intended to maintain normal operation of an end clutch valve. To this end, the present invention includes a shift fast control unit 30 including a 2-3 shift fast valve, wherein the E / C output line L7 of the 2-3 shift fast valve to the kick down servo And is connected to the E / C output line L7 of the 2-3 / 4-3 shift valve, which is again connected to the left end line of the fast valve, and the right end line of the fast valve is connected to the 2-3 / The SA input line L5 is connected to the third speed line and is connected to the connection line L8 of the valve with the rear clutch release valve. The shifting quality of the automatic transmission is improved, and the durability of the automatic transmission, in particular, the durability of the end clutch can be improved.