摘要 |
A cartridge valve assembly (19) including a sleeve valve (49) fixed within a valve housing (17), and a spool valve (47) moveable both axially and rotatably within the sleeve valve. Rotation of an input (35,39) causes rotation of a cam member (43) and the spool valve, and the engagement of the cam member (43) with a cam surface (57) results in axial movement of the spool valve within the sleeve valve. The spool and sleeve valves define a neutral axial and rotational position (FIG. 5), and rotation from neutral in a first direction (FIG. 6) communicates fluid from an inlet port (21) to a first actuator port (25), and rotation from neutral in a second direction (FIG. 7) communicates fluid from the inlet port to a second actuator port (27). In either case, the axial movement of the spool valve (47), relative to the sleeve valve (49) is the same. The spool valve defines a load holding land (97) which, in the neutral position (FIG. 5) engages a seat (99) defined by the interior of the sleeve valve (49), to block the flow of fluid from the first actuator port (25), and provide an integral load holding capability, with no extra valving or plumbing.
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