GB1317651A - Oscillatory and reciprocating hydraulic motors - Google Patents

Abstract

1317651 Hydraulic motors; hydraulic actuators INTERNATIONAL HARVESTER CO 25 June 1970 [22 July 1969] 30905/70 Headings F1D and F1F A motor including semi-rotary vane or a linear piston movable by the fluid, includes a bleeder valve having a housing connected between a source of hydraulic fluid and the motor and having an inlet port for receiving fluid, a port for delivering fluid to operate the vane or piston and a return port for bleeding fluid from the motor, and a sensing means reciprocable in the housing and responsive to the movement of the vane or piston which is operable on the valve member of the bleeder valve so that when the vane or piston approaches one of two end positions between which it is movable, fluid is withdrawn from the motor through the return port. In one embodiment, a motor 10, Fig. 5, includes a vane 26 having ears 22 which except for V-shaped grooves 23 mask ports 24, 25 in the end positions of the vane. The vane is mounted on a shaft 15 on which is keyed a cam 80, Fig. 4, co-operable with sensing members 61, 61' one for each identical bleeder valve 50 or 50'. Each valve comprises a housing 60 slidably mounting a spring- loaded valve piston 62 and formed with ports 70, 71, 72 connected respectively with a source of pressure fluid via a control valve 99, the motor, and sump also via the control valve. A rear land 62R of the valve piston includes a reduced diameter portion 64 so that as the vane approaches the end of its travel some of the fluid entering the appropriate port to move the vane is increasingly directed through the port 72 to sump to cushion the movement of the vane. The V-shaped grooves 23 on the ears 22 permit the initial admittance of fluid through the appropriate port to commence movement of the vane and a final slow leakage at the end of movement. Axial and radial passages through the valve piston hydraulically balance the valve. In an alternative embodiment a piston 113, Fig.6, reciprocates in a cylinder 110. In this instance a single bleeder valve 150 is fitted. Rings 120 formed with metering grooves 121 are drawn into juxtaposition with port 126 or port 127 as the piston finally approaches the end of its travel.