| 摘要 |
865,635. Vehicle power steering. BOULTON PAUL AIRCRAFT Ltd. Aug. 1, 1958 [Aug. 12, 1957], No. 25417/57. Class 79(5). In a hydraulic servo system for steering &c. the control valve 40 operated from the steering wheel through a reversible worm drive 42, 43 is mounted within the movable actuating piston 25 and has the pressures on opposite sides of the piston 22 imposed across it to piovide feel and permit self-centering by castoring action, the valve 40, in its rest position permitting flow to apply equal pressure loads at opposite ends of the piston 25. The steering column 2 is rotatably mounted on a bearing 10 in the end of a cylindrical sleeve 3 and is located against endwise movement by a flange 12 and ring 13 engaging, the inner bearing race. The end of the column 2 is supported by a ball race 5 in the sleeve 3 and carries internal worm teeth 43 for actuating a worm 42 which is coupled to the valve 40 through a rod 41 and link or ball joint 41a. Rotation of the worm 42 is prevented by splines 44 which are engaged between a shoulder 45 and a ring 48 fixed within a hollow piston rod 23 and which permit limited axial movement for operating the valve 40 and act as stops for manual operation in the event of an hydraulic breakdown. Rotation of the piston 25 within the cylinder 19 is prevented by the engagement of splines 35 on the hollow piston rod 23 engaging grooves 36 in a fixed liner 37. The valve 40 is slidable within a cylindrical liner 39 having ports 64, 65 opposite lands 62, 63 and connected to opposite ends of the operating cylinder through passages 67, 71. In the rest position the lands are arranged to leave the ports partially open so that equal pressure loads are applied to opposite ends of the actuator. Pressure fluid is supplied to the central annular channel 61 through a coupling 82 and passage 83 and is exhausted from spaced annular passages 59, 60 through ports 78, 79, leading to a central bore 75 in the valve 40 from which the fluid escapes through an end port 80 and coupling 81 A. Reduced ends 54 of the valve 40 are slidable in sleeves 53, 55 and provide annular passages 69, 73 which are pivoted to the cylinder passages 67, 71 to provide "feel". The effect of feel is further supplemented by a spring 51 engaged between a sleeve 49 and collar 52 on the operating rod 41. |
