Lock-up control device for lock-up type torque converter and multi-stage hydraulic pressure control device suitable for the lock-up control device

摘要

A lock-up type torque converter includes a lock-up control device having a lock-up control valve, an input element and an output element. The torque converter also includes a supply line to supply operating fluid to the lock-up control valve. The supply line has a regulator valve for regulating pressure of the operating fluid in the supply line by selectively connecting the supply line to an oil cooler or a drain line. An applying chamber is situated on a first side of a lock- up clutch and a releasing chamber is situated on a second, opposite side of the lock-up clutch. In a releasing position, the lock-up control valve supplies operating fluid to the torque converter such that the operating fluid flows from the releasing chamber to the applying chamber to shift the lock-up clutch to a converter state in which the input element and the output element are indirectly mechanically linked to each other through the operating fluid. In a lock-up position the lock-up control valve supplies operating fluid to the torque converter such that the operating fluid flows from the applying chamber to the releasing chamber to shift the lock-up clutch to a lock-up state in which the input element and the output element are directly mechanically linked to each other.