Abstract: In a four-wheel steering system for a vehicle, a rear wheel turning mechanism for turning the rear wheels is controlled so that the ratio of the rear wheel turning angle to the front wheel turning angle changes with change in the vehicle speed. The ratio of the rear wheel turning angle to the front wheel turning angle is set so that the vehicle lateral acceleration response characteristics and the vehicle heading response characteristics generated by operation of the steering wheel approximate each other as far as possible.

Abstract: The present invention relates to a suspension system in a vehicle body assembly which is used in common for a four-wheel-steering vehicle and a two-wheel-steering vehicle. In the present invention, a front suspension system installed in a four-wheel-steering vehicle is set to have a higher lateral rigidity than when installed in a two-wheel-steering vehicle, so that the front suspension system can withstand the lateral forces acting on the front wheels of the four-wheel-steering vehicle, said lateral forces being larger than those in a two-wheel-steering vehicle. Further, the suspension system is set to have a lowered rigidity against rolling of the vehicle body where it is installed in a four-wheel-steering vehicle, whereby the riding comfort can be maintained as that of the two-wheel-steering vehicle.

Abstract: A steering mechanism of a vehicle including a front wheel steering mechanism for steering front wheels of the vehicle, a steering wheel wheel for effecting a steering movement of the front wheel steering mechanism to a desired angle, a rear wheel steering mechanism for steering rear wheels of the vehicle, a control unit for effecting a steering movement of the rear wheel steering mechanism in relation with the steering movement of the front wheels. The arrangement is such that a ratio of the steering angle of the rear wheel to the steering angle of the front wheel is increased in the same direction of steering as the steered direction of the front wheels as the rate of the steering operation for the steering wheel is increased so as to obtain a desirable steering movement of the rear wheels.

Abstract: A steering system for a vehicle comprises a front wheel turning mechanism for turning the front wheels in response to operation of a steering wheel, a steering ratio changing mechanism inserted into the front wheel turning mechanism to change the ratio of the turning angle of the steering wheel to the turning angle of the front wheels, and a vehicle speed sensor for detecting the vehicle speed. The steering ratio changing mechanism is controlled to increase the ratio as the vehicle speed increases, and as the vehicle speed increases, the control speed of the steering ratio changing mechanism is lowered.

Abstract: A four-wheel steering system for a vehicle comprises a steering wheel, a front wheel turning mechanism for turning the front wheels in response to operation of the steering wheel, a rear wheel turning mechanism including a rear wheel steering ratio determining circuit for determining the rear wheel steering ratio and an actuator for turning the rear wheels according to the rear wheel steering ratio determined by the rear wheel steering ratio determining circuit. The four-wheel steering system is provided with a road condition sensor for detecting road surface conditions which can weaken the road gripping force of the wheels and a rear wheel steering ratio controller for changing the rear wheel steering ratio determined by the rear wheel steering ratio determining circuit so that the rear wheel steering ratio is increased when the road condition is such that the road gripping force of the wheels can be weakened.

Abstract: A vehicle four wheel steering system including a rear wheel steering mechanism with a power assist device. The rear wheel steering mechanism includes a steering rod extending transversely of the vehicle and having the opposite ends connected with tie rods which are in turn connected with knuckle arms of the rear wheels. The steering rod is provided with a power cylinder in which a piston is slidably disposed. The piston is provided on the steering rod and defines hydraulic chambers in the cylinder. A control valve is provided to control hydraulic oil supply to the power cylinder. The control valve has a casing which is connected with the steering rod through an interconnecting section and hydraulic oil passages are formed in the interconnecting section for passing hydraulic oil to and from the power cylinder.

Abstract: A steering mechanism of a vehicle including a front wheel steering mechanism for steering front wheels of the vehicle, a steering handle wheel for effecting a steering movement of the front wheel steering mechanism to a desired angle, a rear wheel steering mechanism for steering rear wheels of the vehicle, a control circuit for effecting a steering movement of the rear wheel steering mechanism in relation with the steering movement of the front wheels. The arrangement is such that a ratio of the steering angle of the rear wheel to the steering angle of the front wheel as considered in the same direction of steering is increased in accordance with an increase in the steered angle of the front wheel.

Abstract: A steering system for a vehicle comprises a transmission ratio changing mechanism inserted between the steering wheel and dirigible wheels of the vehicle to change the transmission ratio, thereby changing the steering ratio, a vehicle speed detecting means and a controller which receives a vehicle speed signal from the vehicle speed detecting means and controls the transmission ratio changing mechanism so that the steering ratio is reduced as the vehicle speed increases and the rate of change of the steering ratio with the vehicle speed is larger in a low vehicle speed range than in a high vehicle speed range.

Abstract: In a four-wheeled vehicle, the rear wheels are turned as well as the front wheels in response to operation of the steering wheel. The rear wheel turning angle characteristics relative to the front wheel turning angle is changed according to the vehicle speed. In the low to high vehicle speed region, the rear wheel turning angle is increased with increase of the front wheel turning angle and the increasing rate is increased as the vehicle speed increases. In the very low vehicle speed region, the rear wheels are not turned until the front wheels are turned at least by a predetermined angle, and are turned in the direction opposite to the front wheels when the front wheels are turned by an angle larger than the predetermined angle. The rear wheel turning angle in the opposite direction is changed in proportion to the front wheel turning angle.

Abstract: A four-wheel steering system comprises a steering wheel; a steering shaft which is connected to the steering wheel to be rotated in response to operation of the steering wheel and is provided with a first pinion fixedly mounted thereon; a rack bar which is supported for sliding motion in the transverse direction of the vehicle body, is provided with a first rack gear in mesh with the first pinion and a second rack gear, and is connected to the right and left front wheels by way of tie rods, a rear wheel turning force taking-out mechanism which includes a second pinion in mesh with the second rack gear on the rack bar and a rod member connected to the second pinion, and which converts the sliding motion of the rack bar into rotation of the rod member; and a rear wheel turning mechanism which is arranged to turn the rear wheels in response to rotation of the rod member.

Abstract: In a four-wheel steering apparatus of a vehicle for steering also the rear wheels in conformity with the steering of the front wheels by a steering wheel, a control force for a rear wheel steering device is mechanically taken out from a front wheel steering device and is suitably controlled in the intermediate portion and is transmitted as a steering control force to the rear wheel steering device, whereby the front wheels and the rear wheels are steered in the same direction when the absolute value of the steering angle of the front wheels is less than a predetermined value, and the rear wheels are steered in the direction reverse to the front wheels when the absolute value is greater than the predetermined value.

Abstract: The rear wheels of a vehicle are turned in response to the turning of the front wheels upon operation of the steering wheel. A rack member is provided to be operatively connected with a movable member of the front wheel steering system which is moved right and left in response to operation of the steering wheel so that the rack member is moved together with the movable member. The rack member is in mesh with a pinion fixed to an end of an output shaft whose rotation is transmitted to the rear wheel steering system as steering force for moving it by way of a transmission shaft.

Abstract: A steering system in an automobile comprising a steering wheel and a steering shaft rotatable together with the steering wheel, a steering linkage connecting between spaced wheel carriers, a steering gear connecting between the steering shaft and the steering linkage for, when the steering wheel is rotated in one of the opposite directions from a neutral position, causing the steering linkage to displace in one of the opposite directions generally longitudinally thereof for steering the road wheels, an adjustable damper capable of exerting an adjusted damping force and disposed between a portion of an automobile body structure and a portion of the steering linkage for minimizing an oscillatory motion of the steering linkage in a direction generally longitudinally thereof, a valving mechanism for adjusting the damping force exerted by the damper, a detector for detecting a parameter representative of the steered condition of the road wheels and generating an output indicative of the parameter when the paramete

Abstract: A motor vehicle including a body, steerable front wheels and rear wheels for supporting the body, front suspension mechanisms between the body and the front wheels and rear suspension mechanisms between the body and the rear wheels, a power steering mechanism for operating the front wheels with desired steering characteristics, the front and rear suspension mechanisms including suspension struts which resist vertical movements of the body with respect to the wheels with damping powers and having spring rates. A control circuit is provided for changing the ratio of the damping powers and the spring rates in the front suspension mechanisms relative to those in the rear suspension mechanisms and at the same time changing the power assist force of the steering mechanism.

Abstract: A four-wheel steering system for a vehicle comprising a steering mechanism including a steering wheel, a front wheel turning mechanism operatively connected to the steering mechanism to turn the front wheels according to the turning angle of the steering wheel, a rear wheel turning mechanism operatively connected to the steering mechanism to turn the rear wheels in response to operation of the steering wheel, and a rear wheel steering ratio changing mechanism for changing the ratio of the turning angle of the rear wheels to the turning angle of the steering wheel.

Abstract: A motor vehicle including a body, steerable front wheels and rear wheels for supporting the body, front suspension mechanisms between the body and the front wheels and rear suspension mechanisms between the body and the rear wheels, a power steering mechanism for operating the front wheels with desired steering characteristics, the front and rear suspension mechanisms including suspension struts which resist vertical movements of the body with respect to the wheels with damping powers and having spring rates. A control circuit is provided for changing the damping powers and the spring rates in all of the suspension mechanisms and at the same time changing the power assist force of the steering mechanism.

Abstract: In the four-wheeled vehicle, both the front and rear wheels are turned in response to operation of the steering wheel. The turning angle of the rear wheels is controlled in accordance with a turning angle ratio characteristic curve defined on a .theta.F-.theta.R plane wherein .theta.F and .theta.R respectively represent the turning angles of the front and rear wheels. The turning angle ratio characteristic curve is substantially a broken line having a positive inclination in the region where the value of the front wheel turning angle .theta.F is smaller than a predetermined value and having a smaller inclination in the region where the value of the front wheel turning angle .theta.F is larger than the predetermined value. The turning angle ratio characteristic curve is changed according to the vehicle speed so that the turning angle ratio .theta.R/.theta.F is increased as the vehicle speed increases.

Abstract: A power steering device for a vehicle comprises a steering wheel, a steering linkage operatively connecting the steering wheel to dirigible wheels of the vehicle and a power assisting device inserted into the steering linkage to assist the steering force of the steering wheel. A steering shaft of the steering linkage rotated with the steering wheel to transmit the steering force from the steering wheel to the power assisting device is divided into first and second parts. A pair of coil springs are inserted between the first and second parts of the steering shaft to connect them with each other and is adapted to be elastically deformed to produce a rotational displacement between them when the steering wheel is rotated. A set load is placed on the coil spring so that the coil spring can be elastically deformed only when the steering force from the steering wheel exceeds a predetermined value.

Abstract: A steering device for a vehicle comprises a steering wheel operatively connected to dirigible wheels of the vehicle by way of a steering linkage so that the dirigible wheels are turned in response to rotation of the steering wheel. A portion of the steering linkage which is rotted with the steering wheel is divided into first and second parts and the first and second parts are connected with each other by way of a pair of coil springs and a damper. The coil springs are adapted to be elastically deformed to produce a rotational displacement between the first and second parts upon rotation of the steering wheel while the damper is adapted to damp the steering force of the steering wheel. An adjustment means is provided for changing the damping characteristics of the damper according to speed of the vehicle and/or the steering torque of the steering wheel.

Abstract: A power steering system including a power cylinder and a hydraulic pump for supplying a hydraulic pressure to the power cylinder through a control valve to produce a hydraulic assisting force. A control device is provided to drive the hydraulic pump only when one or both of the vehicle power clutch disconnecting member and the brake actuating member are actuated under a vehicle speed lower than a predetermined value.