Hydraulic system for pressure actuation of a variator of an automatic gear with an emergency drive device

摘要

The hydraulic system is connected with a lubricating oil circuit (10) in which at least one lubricating valve (14) and a cooler (13) are arranged. Oil from an oil source (4) is fed to the hydraulic system and the circuit. A hydraulic emergency drive device is also provided. This has an emergency valve (29) for setting a constant pressure ratio between a primary (19) and a secondary disk set (20) of the variator (7). The hydraulic system includes a device for reducing the thermal load in emergency drive mode. This device increases the oil flow through the cooler in emergency mode and reduces the pressure at the output side of the cooler.