Patent GB-1424937-A (GB)
Title: Automotive steering system process for the production of bis-halogen carbonyl anilines
IPC: B62D5/00
Filed: 1974-03-01
Abstract: 1424937 Power steering NISSAN MOTOR CO Ltd 1 March 1974 [5 March 1973 20 March 1973] 9308/74 Heading B7H In a power steering system an electric control circuit produces a signal in response to turning of the steering wheel 102 to actuate a motor 98 which rotates a piston valve 40 controlling fluid to a hydromechanical leverage unit 14 which effects right or left turn of the steered road wheels, the piston-valve 40 also moving longitudinally between first and second positions across an equilibrium depending on its rotational position, and a valve reset mechanism operatively connected between the leverage unit 14 and the piston-valve 40 moves the piston-valve from the first or second position back to the equilibrium position. When the wheel 102 is turned to effect right turn, say, of the wheels 12, the rotational movement is modulated to an angle sensor 110 and the signal delivered to control module 112 is further modified in accordance with signals from the vehicle velocity sensor 114, and the wind sensor 116. Comparator 120 compares the signal from module 112 with the signal from the angle  sensor to thus produce a signal representative of their difference which is converted into a drive  current for energizing motor 98 until the pulse signal disappears. As motor 98 is energized piston valve 70 is driven to rotate relative to nut member 84, and due to the screw portion 82, the valve 70 is moved along its longitudinal axis, so that fluid pressure is directed from source 60 to chamber 22 to act on piston 18 whilst  fluid in chamber 22<SP>1</SP> is discharged into sump 64. Movement of piston 18 rightwardly causes  steered wheels 12 to turn via sector 28 and steering linkage 10. Also, the longitudinal displacement of piston 18 causes grooved shaft 32 to rotate and such rotation is transmitted through gears 92, 86 to unut member 84 which is driven to rotate relative to screw portion 82 to bring about longitudinal movement of pistonvalve 70 back to its equilibrium position. Left turn of the road wheels 12 will be effected similarly to right turning. A guide signal sensor 118 connected to module 112 allows the system to be shifted to an automatically controlled mode of operation. In a modification, Fig. 2, the system is such that in the event of pressure from source 60 dropping, or the pressure acting on piston-valve 70 and the piston 18 being reduced below a working level, a pressure sensor 172 supplies a signal to valve actuator 170 so that control valves 158, 166 are actuated for fluid from an auxiliary source 152 to be directed into chamber 148 of the steering shaft support 128 and at the same time fluid from the primary source 60 is discharged to a sump 168. Pressure thus acts on sleeve 142 which accordingly presses against sleeve 144 for gear 106 to be axially moved on the grooved end 132 of steering shaft 104 toward gear 92 on grooved shaft 32 against force of spring 138. Clutch teeth 134, 132 on the gears are thus engaged so that rotational motion on steering wheel 102 can be transmitted to shaft 32 of the leverage unit 14. A reaction unit 182 may be connected to steering wheel 102 via gears 106, 108 so as to give the operator a feeling of reaction proportional to the steering load.