Mazda Motor Corporation

Nippon Seiko Kabushiki Kaisha

Nippon Seiko K.k.

Mazada Motor Corporation

Nippon Seiko Kaisha

Satoru Shimada

Isamu Chikuma

Hiroshi Eda

Hirotaka Kanazawa

Shigeki Furutani

Teruhiko Takatani

Akihiko Miyoshi

Yukio Noguchi

Takatani Teruhiko

Furutani Shigeki

Yoichi Takeda

Kazuo Chikaraishi

A four-wheel steering apparatus comprises a front wheel steering member for steering front wheels by being displaced according to a movement of a steering wheel, a rear wheel steering mechanism for steering rear wheels, a coupling mechanism for mechanically coupling together the front wheel steering member and an input member of the rear wheel steering mechanism, and a play mechanism provided between an end of the coupling mechanism and the front wheel steering member or the input member or in an intermediate part of the coupling mechanism, the play mechanism effecting transmission of displacement only when a displacement in excess of a predetermined amount is produced in either direction from a position corresponding to a neutral position with respect to the steering angle of the front wheels. The rear wheel s6teering mechanism includes a mechanism for steering the rear wheels according to a movement of the input member and an independent steering mechanism for steering the rear wheels independently of displacement of the front wheel steering member.

Four-wheel steering apparatus

Rotaton of a steering wheel is transmitted to a steering ratio changing mechanism which displaces an output displacement member according to the steering wheel turning angle to obtain a desired steering ratio. A displacment transmission member transmits the displacement of the output displacement member to a valve member of a hydraulic switching valve and a wheel turning rod is displaced under the force of a hydraulic power cylinder in response to displacement of the valve member. The displacement transmission member is operatively connected to the output displacement member, the valve member and the wheel turning rod to be operated to displace the valve member in a predetermined direction in response to a displacement of the output displacement member and to be operated to displace the valve member in the direction opposite to the predetermined direction in response to a displacement of the wheel turning rod generated by the displacement of the valve member, so that the wheel turning rod is displaced in response to displacement of the output displacement member with the valve member being hardly displaced.

Vehicle steering system

A four-wheel steering apparatus of a vehicle has a front-wheel steering mechanism for steering front wheels, a rear-wheel steering mechanism for steering rear wheels, a steering gear mechanism operatively connected to the front-wheel steering mechanism and effecting a steering operation, a steering angle extracting mechanism operatively connected to the steering mechanism and extracting the steering angle of the front wheels, the steering angle extracting mechanism comprising a restraining member movable axially along the axis of the front wheels in response to the steering operation, and a string member fixed to the restraining member and displaceable in the lengthwise direction thereof in response to the movement of the restraining member, and rear-wheel steering angle control mechanism operatively connected to the steering angle extracting mechanism for controlling the amount and the direction of steer to be transmitted to the rear wheels, the rear-wheel steering angle control mechanism comprising a rotatable member rotatable in response to the displacement of the string member, and a transmission member movably engaged with the rotatable member and movable in conformity with the amount and the direction of rotation of the rotatable member for transmitting the amount of movement thereof to the rear-wheel steering mechanism.

Four-wheel steering apparatus of a vehicle

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.

Vehicle four wheel steering system

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. There are provided a first resilient pressing mechanism which presses one of the first and second rack gears, from the rear, towards the pinion in mesh therewith, and a second resilient pressing mechanism which presses the pinion in mesh with the other of the first and second rack gears toward said the other of the first and second rack gears.

Four-wheel steering system for vehicle

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. In the intermediate portion, the taken-out control force is divided into a same direction steering control force for steering the rear wheels in the same direction as the front wheels and a reverse direction steering control force for steering the rear wheels in the direction reverse to the front wheels, and the reverse direction steering control force is absorbed and only the same direction steering control force is transmitted to the rear wheel steering device when the absolute value is less than the predetermined value, and the same direction steering control force is absorbed and only the reverse direction steering control force is transmitted to the rear wheel steering device when the absolute value is greater than the predetermined value.

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.

A four-wheel steering system for a vehicle has a rear wheel steering ratio changing means which changes the rear wheel steering ratio in accordance with rear wheel steering ratio characteristics predetermined according to the vehicle speed, and an inhibiting means which inhibits the rear wheel steering ratio changing means from changing the rear wheel steering ratio when the steering wheel is turned right or left from its neutral position.

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.

Growing community of inventors

Maebashi, Japan

Satoru Shimada