GB391775A - Improvements in hydraulic steering gear suitable for vehicles, ships and the like - Google Patents

Abstract

391,775. Steering vehicles and ships. ARMSTRONG, J. J. V., 12, Church Street, Liverpool.-(Vickers, Inc. ; 7752, Dubois Street, Detroit, Michigan, U.S.A.) Oct. 26, 1931, No. 29614. [Class 79 (v).] Comprises hydraulic servomotor steering- gear in which a valve coaxial with and directly operated by the steering-shaft or column controls an hydraulic motor mounted directly on a cross-shaft operating the members to be steered. The gear has a " follow-up " action, and is operable by hand if fluid-pressure fails. The steering-shaft 4 has fixed thereon a coaxial valve 8 and has a lost-motion connection 31 with a worm 5 gearing with a sector on the rocker or cross-shaft 3 operating the steering wheels. The valve 8 controls the fluid connections between a continuously-driven pump A and a vane motor 27 on the cross-shaft 3, so that when the valve is rotated by the shaft 4 the motor is rotated by fluid pressure in the corresponding direction and operates the steering wheels. At the same time the motor rotates the worm 5 and a valve member 10 fixed thereto so that when the movement of the shaft 4 stops the motor stops as soon as the member 10 has caught up to the shaft 4 and valve 8. The valve comprises a member 8 with longitudinal grooves 11 and a sleeve 13 fixed to 8 and provided with ports 14 each of which always registers with a circumferential groove a, b, c, or d formed in the casing 1 of the gear. The grooves a, b communicate with outlet and inlet ports 17, 16 from the pump A, and the grooves c, d communicate with ports 18, 19 leading to the motor. The valve 8 encloses the member 10 fixed to the worm 5, the lost-motion connection 31 allowing a slight amount of relative rotation between these parts. The member 10 has ridges 12 slightly narrower than the grooves 11, so that when the gear is stationary and the parts 8, 10 are in the neutral position shown in Figs. 6 and 7 oil can circulate from the pump through the valve and back to the pump, pressure being maintained in the motor chambers at the same time. When the valve 8 is moved from the neutral position as shown in Fig. 8, the lag of the member 10 causes the ridges 12 to close the communication between grooves a, b, whilst leaving a connected to c or d, and b to d or c. The motor is thus energized and rotates the shaft 3, while the valve member 10 follows up the valve 8. When the steering- shaft 4 is stopped the valve member 10 is returned to its neutral position relative to the valve 8 by the action of centring springs forming part of the lost-motion connection 31. Byepass and relief valves 40, 41 are provided in case liquid circulation is stopped or if hand operation of the gear is necessary. The motor chambers are formed in a member 22 and a cover 2 of the gear casing 1, and annular passages 29, 30 for the liquid are provided in the members 22, 2. The gear is bolted to the frame by means of the flanges 20 on the cover.