Transmission hydraulic control unit

摘要

A hydraulic system of a transmission, especially of an automatic transmission of a motor vehicle, having several pressure circuits which can be loaded with hydraulic fluid from a pressure source and in relation to the supply of different areas of the transmission are differently prioritized. The pressure in the pressure circuits is adjustable according to a system valve and one of the pressure circuits comprises a cooling device for the hydraulic fluid and a lubrication circuit located downstream of the cooling device. Between the cooling device and the lubrication circuit is provided a bypass pipe lockable via a valve unit which can be controlled via the valve unit so that the hydraulic fluid flow rate to be passed via the cooling device can be adjusted without changing the hydraulic fluid flow rate to be fed to the lubrication circuit.