GB862929A - Improvements in or relating to vehicle power steering mechanism - Google Patents

Abstract

862,929. Vehicle power steering. MASSEYFERGUSON (UNITED KINGDOM) Ltd. April 22, 1959 [May 3, 1958], No. 14198/58. Class 79(5). A power-assisted steering gear of the type in which a servomotor is operated in the required direction so long as a control valve 26 is held to the appropriate side of a neutral position has the control valve connected to an actuator consisting of the outer member 18 of a bearing 17 participating in axial movements of the steering column shaft 14 in response to steering movements. The shaft 14 is connected by a recirculating ball type of nut and screw an arm and two pinions with the steering linkage and is mounted in a column 12 provided with a bearing 20 on which the member 18 may slide within limits determined by a circular clip 22 and a shoulder 23. A pin 24 prevents rotary movement of the member 18 and forms a connection with an adjustable link 25 secured to the valve 26 which is held in a central position by a spring 42 arranged 'between a sealing ring 44 and a washer 43 bearing partly on a shoulder 45 on the valve and a shoulder 46 on the valve casing 27. Oil passes from a central inlet 33 past clearances on faces 37 to an outlet 34 until the valve is displaced to close one of the clearances and provide a pressure difference on the servomotor. When the valve is used in an agricultural tractor the clearance may include spaced, tapered flats to make the cut-off action less abrupt. The valve may be located at the rear of the steering column and be connected to the member 18 by a bifurcated' first order lever.