HYDRAULIC SUPPLY SYSTEM FOR A HYDRAULICALLY ACTUATED AUTOMATIC TRANSMISSION

摘要

A hydraulic system for a hydraulically actuated automatic transmission, especially a continuously variable transmission, comprises a pump for supplying hydraulic pressure in a supply pipe that is connected to a regulating valve and is connected to a control pipe by means of a pilot valve. A control valve which allows the pressure in the control pipe to be adjusted is arranged in the control pipe, said pressure determining the position of the speed ratio-regulating valve. The hydraulic system further comprises an auxiliary pump which can be driven by an auxiliary drive that is separate from the drive of the pump. The discharge pipe of the auxiliary pump is connected to the control pipe by means of a first valve that opens in the direction of the control pipe while being connected to the supply pipe by means of a second valve which opens in the direction of the supply pipe.