GB1022320A - Power assisted steering mechanisms - Google Patents

Abstract

1,022,320. Power assisted steering. FORD MOTOR CO. Ltd. Oct. 20, 1964 [Dec. 9, 1963], No. 42709/64. Heading B7H. Movement of input member 51 of a power assisted steering mechanism causes fluid pressure to both actuate power piston 23 and move output member 24 relative to the power piston to reduce the backlash between them. The power steering mechanism comprises two relatively rotat- 'able valve discs 55, 53 resiliently connected by C- spring 58 keyed at 56 and 54, respectively to input shaft 51 and the extended end of worm 45, the shaft 51 and worm 45 being connected by a splined coupling 52 to permit limited relative motion. When the torque on input shaft 51 exceeds the loading of spring 58, valve disc 55 is moved relative to disc 53 directing hydraulic pressure fluid from inlet 12 and chamber 61 to conduits 66 and 67 and cylinder chamber 64 to move the piston to the left, fluid from cylinder chamber 68 passing through conduit 71 and the control valve to valve chamber 63 and outlet 18 to a fluid reservoir. To move the piston to the right the control valve connects chamber 68 to inlet 12 and chamber 64 to outlet 18. Conduit 67 is connected by passages 86 and 85 (Fig. 3) to chamber 84 containing reduced area end face 28 of shaft 24 and the chamber 68 communicates with the annular face 29 of the shaft 24 in order to apply an end force to the shaft 24 to reduce the backlash between socket 37 of the shaft and spherical extension 38 of piston 23 when the steering is in operation and either chamber 64 or 68 is pressurized.