Hydraulic Control System.

摘要

1,166,238. Change-speed control. INTERNATIONAL HARVESTER CO. 1 Nov., 1966 [6 Jan., 1966], No. 20501/69. Divided out of 1,165,013. Heading F2D. An hydraulic control system for the supply of cooling and lubricating liquid to the friction members and bearings of the range shift clutches of a vehicle transmission includes a selector valve which, in its neutral setting, admits low pressure liquid to all the clutches and bearings, and which, when moved to an engaged setting, admits high pressure liquid to engage the selected clutch and maintainthelowpressure supply to the remaining clutches and bearings, and also includes a unidirectional valve associated with the selector valve. As shown for an arrangement including range shift and reverse clutches 122 with their associated bearings 124, liquid is supplied to the actuators 12, 16 by a pump 98 through the selector valve 10 with which are associated high and low pressure relief valves 94, 102, the one-way valve 118, and a restriction R in the supply line to the individual clutches and bearings. In the neutral setting shown valve 94 is by-passed, the liquid passing from selector valve 10 through the one-way valve 118, the restriction R causing a pressure build up to the point at which relief valve 102 opens. On moving the selector valve to the F1 setting, for example, high pressure liquid is fed to the forward actuator 12 which, when filled, causes increased flow through restriction R and a pressure build up through selector valve 10, high pressure junction 92 to relief valve 94 which operates to maintain the desired high pressure in the engaged clutch. The lower pressure junction 100 is maintained at the original low pressure by valve 102, the supply of the low pressure liquid being continued through ports F2, R1 to the inoperative clutches while the valve 118 remains closed to prevent loss of pressure through the open port 114 of the selector valve.