Patent ID: 7278951
Filing Date: 2007-10-09
Classification: F16H,Y10T

Abstract:
1. A hydraulic circuit for a continuously variable transmission comprising a continuously variable ratio transmission unit (“variator”) which is controllable by application of fluid pressure to at least one hydraulic actuator acting on a movable torque transmission element of the variator, the circuit comprising a fluid supply line connected to the hydraulic actuator for feeding fluid to and from the hydraulic actuator, means for providing a flow of fluid through the fluid supply line, variable control valve means in the fluid supply line downstream of the connection to the hydraulic actuator for generating an adjustable back pressure in the fluid supply line, and further valve means connected to the fluid supply line, the further valve means being responsive to rate of fluid flow in the supply line, downstream of the connection to the hydraulic actuator and upstream of the control valve means, thereby to selectively modify pressure in the supply line in response to changes in flow rate created by movement of the actuator.