A HYDRAULIC CONTROL CIRCUIT FOR A CONTINUOUSLY VARIABLE TRANSMISSION

摘要

A hydraulic control circuit is disclosed for a continuously variable transmission comprising a continuously variable ratio transmission unit ("variator") 10, the circuit comprising a supply line 106 and means (which may take the form of a pump 110) for providing a flow of pressurised fluid in the supply line, means (which may comprise a pressure control valve 116) for generating a back pressure in the supply line, and at least one connection for feeding fluid from the supply line to a hydraulic actuator 100 acting on a movable torque transmission 23-37 element (which may comprise a roller 28) of the variator 10. The valve means 152 connected to the supply line allows pressure in the supply line to be selectively modified in response to rate of flow in the supply line.