LOCK-UP CONTROL DEVICE FOR TORQUE CONVERTER IN AUTOMATIC TRANSMISSION FOR VEHICLE

摘要

A lock-up control device for a torque converter in an automatic transmission for a vehicle comprises a modulator valve Mv disposed in an oil passage for connecting an oil pressure cylinder 14 of the lock-up clutch with an oil pressure source, the modulator valve being composed of a valve body 86 for opening and closing said oil passage, a spring for biasing said valve body in a valve-opening direction, a first oil pressure chamber in which oil pressure biases the valve body in a valve-closing direction and a second oil pressure chamber in which speed-responsive oil pressure biases said valve body in the valve-opening direction. A solenoid valve 96, 97 releases pressure in said second oil pressure chamber to disengage the lock-up clutch when the throttle is released. A timer valve Tv disengages the clutch during a ratio shift. The lock-up clutch slips when speed is low and torque is high.