Patent ID: 8439798
Filing Date: 2013-05-14
Classification: F16H,Y10T

Abstract:
1. A hydraulic apparatus for an automatic transmission mounted on a vehicle and equipped with a torque converter having a lockup clutch and a transmission mechanism that inputs an output of a prime mover through the torque converter and transmits power to a wheel of the vehicle, comprising: a power transmission regulating member that is equipped with a cylinder chamber and regulates the power transmitted by the transmission mechanism in response to hydraulic pressure of operating oil supplied to the cylinder chamber from a hydraulic pressure source; a first control valve interposed between an oil chamber of the lockup clutch and the hydraulic pressure source to supply/discharge the hydraulic pressure to/from the oil chamber so as to control engagement/disengagement of the lockup clutch and capacity of engagement; a first electromagnetic solenoid valve that is adapted to control operation of the first control valve; a second control valve interposed between the hydraulic pressure source and the cylinder chamber of the power transmission regulating member to control operation of the power transmission regulating member by supplying/discharging the hydraulic pressure, to/from the cylinder chamber; a second electromagnetic solenoid valve that controls operation of the second control valve; a switching valve interposed between the oil chamber of the lockup clutch and the first control valve; and a controller that stops supply of current to the second electromagnetic solenoid valve so that the second electromagnetic solenoid valve operates the switching valve to disengage the lockup clutch, when detecting that at least one of the first control valve and the first electromagnetic solenoid valve is failed and that the lockup clutch is locked in engaged condition.