Mazda Motor Corporation

Nippon Seiko Kabushiki Kaisha

Toyo Kogyo Co., Ltd.

Delta Kogyo Co., Ltd.

Tokai Trw & Co., Ltd.

Nippon Seiko K.k.

Hirotaka Kanazawa

Shigeki Furutani

Teruhiko Takatani

Hiroshi Ohmura

Isamu Chikuma

Satoru Shimada

Hiroshi Eda

Yasuhiro Nakashima

Koushun Note

Seita Kanai

Takashi Nakashima

Akihiko Miyoshi

Takeshi Tanaka

Takeshi Edahiro

Takeshi Murai

Ryuya Akita

Naoto Takata

Yoshiaki Mukai

Shunsuke Kawasaki

Hiroki Yoshioka

Masaki Watanabe

Shin Takehara

Fumio Kageyama

Shunji Sakamoto

Toshiro Kondo

Michio Abe

Toshiki Morita

Naoyuki Maeda

Fumitaka Ando

Masao Hideshima

Hitoshi Nakashima

Shigeo Okamizu

Yoshihiro Watanabe

Susumu Yoshida

Shirou Nakatani

Akihiro Furuzawa

Kouji Tsuji

Atsuo Tomoda

Hiroyuki Hayashi

Akira Marumoto

Yoshikazu Yasuda

Koji Fujio

Yutaka Tagashira

Hiroshi Ogawa

Shin Takahara

Nobuhiro Totoki

Hiroyuki Noda

Kozo Harada

Takatani Teruhiko

Furutani Shigeki

Norio Tsukaana

Satoru Tanabe

Shigeuki Okimoto

Akihiro Watanabe

Junji Yoshioka

Noritaka Yasuda

Yoichi Takeda

Hideharu Masumoto

Kazuo Chikaraishi

Yukio Noguchi

In a four wheel steering system, the rear wheel turning mechanism is connected to the front wheel turning mechanism by way of a rear wheel turning angle ratio changing mechanism which is mechanically connected to both the front wheel turning mechanism and the rear wheel turning mechanism and transmits the mechanical displacement input thereinto from the front wheel turning mechanism to the rear wheel turning mechanism to drive the same by an amount the ratio of which to the amount of mechanical displacement input into the rear wheel turning angle ratio changing mechanism gives a predetermined rear wheel turning angle ratio. The rear wheel turning angle ratio changing mechanism is controlled in such a way that, when the front wheels are turned from the neutral position in a middle vehicle speed range, makes the rear wheel turning angle ratio negative for a moment immediately after initiation of turning of the front wheels and thereafter turns the same positive.

Four-wheel steering system for vehicle

Two support members which are supported swingably to the vehicle body through the medium of the support axis extending in up and down direction are provided at the vehicle body end portions of two left and right suspension arm members connecting left and right rear wheels to the vehicle body. Lever parts are extended from the support members toward the opposing direction to each other and are interconnected by a link member. One of the two support members is driven by one actuator for rotation around an support axis, whereby left and right two suspension arm members move in vehicle widthwise direction, opposite to each other, and in synchronism with each other and thus left and right rear wheels are steered symmetrically in toe-in direction or toe-out direction. Since the motive power mechanism part is of simple construction using link members, and engaging parts of gears can be lessened, the device according to the present invention can contribute to compactness and cost reduction and also can restrict 'shaking' in rear wheel steering due to backlash of gears.

Rear wheel steering device for a vehicle

A four-wheel steering system includes a front wheel turning mechanism which turns the front wheels in response to the turning of the steering wheel, a rear wheel turning mechanism which turns the rear wheels in response to the turning of the steering wheel, and a power steering mechanism. The rear wheel turning mechanism changes the rear wheel turning angle ratio, which is the ratio of the rear wheel turning angle to the front wheel turning angle on the basis of predetermined rear wheel turning angle ratio characteristic curve. A selecting switch selects one of a plurality of rear wheel turning angle ratio characteristic curves according to the running condition of the vehicle and causes the rear wheel turning mechanism to change the rear wheel turning angle ratio on the basis of the rear wheel turning angle ratio characteristic curve selected. The assisting force of the power steering mechanism is changed according to the rear wheel turning angle ratio characteristic curve selected by the selecting switch.

Front and rear wheel turning system for vehicle

A reference position detection method of a vehicle rear wheel steering apparatus in the present invention, is provided with steps of setting an input shaft and the yoke assembly at arbitrary angular positions rotating the input shaft by an arbitrary angle to pass a neutral angular position measuring a rotational angle .theta. of the input shaft and a moving amount .delta.1 of an output rod assembly upon rotation of the input shaft rotating the yoke assembly to pass a neutral angular position so that the output rod assembly is stroke-moved by a moving amount -.delta.1 from a stroke position defined by the moving amount .delta.1 of the output rod assembly rotating the input shaft by an angle -.theta. after rotating the yoke assembly, and measuring a moving amount .delta.2 of the output rod assembly; and determining, as a reference position of the yoke assembly, an angular position obtained by rotating the yoke assembly from the rotated state of the input shaft so that the output rod assembly is displaced by -.delta.2.sup.2 /(.delta.1+.delta.2).

Reference position detection method of vehicle rear wheel steering

A vehicle is provided with both a traction control system which reduces driving torque for driving wheels of the vehicle when the driving wheels slip, and an active suspension system which has a cylinder disposed between the vehicle body and each of the wheels of the vehicle and in which suspension properties can be changed by controlling feed and discharge of the hydraulic fluid to and from the cylinders. A control gain of the active suspension system is increased when the traction control system is operating.

Suspension-traction total control system

A vehicle control system includes an active suspension mechanism for providing a rolling property of a vehicle in a cornering operation of the vehicle and a suspension control device for controlling the vehicle in accordance with the rolling property provided by the active suspension mechanism and changing from one rolling property to another. A rear wheel steering mechanism steers a rear wheel in connection with steering of a front wheel, and a steering control device controls the steering of the rear wheel in accordance with a predetermined steering property and changes the steering property for the rear wheel. One of the steering property and the rolling property is changed in synchronism with a change in the other of the steering property and the rolling property. When a reverse phase property is provided for the rear wheel as a steering property and a reverse rolling property is provided for the active suspension system, the visibility of the cornering direction and the operability are improved to accomplish an active operation property. Alternatively when a same phase property is provided for the rear wheel as a steering property, the running stability can be improved.

Suspension control system cooperated with steering control system for

A rear wheel steering device for a vehicle which is provided with a rear wheel steering shaft which steers rear wheels by its displacement, a neutrally holding means which constantly biases the rear wheel steering shaft to the neutral position, a motor which is linked with the rear wheel steering shaft and changes the steering angle ratio which is a ratio of the rear wheel steering angle to the front wheel steering angle by displacing the rear wheel steering shaft and an oil pressure assist means which assists displacement of the rear wheel steering shaft by the motor by oil pressure force. This device is further provided with oil pressure supply means which supplies oil pressure to the oil pressure assist means and oil pressure control means which, when working the motor at the initial check, controls the oil pressure supply means to make the oil pressure assist means supply oil pressure to the oil pressure assist means before working of the motor.

A four-wheel steering system includes a front wheel turning mechanism which turns the front wheels in response to the turning of the steering wheel, a rear wheel turning mechanism which turns the rear wheels in response to the turning of the steering wheel, and a power steering mechanism. The rear wheel turning mechanism changes the rear wheel turning angle ratio, which is the ratio of the rear wheel turning angle to the front wheel turning angle, on the basis of predetermined rear wheel turning angle ratio characteristic curves. The assisting force of the power steering mechanism is changed when the rear wheel turning mechanism fails.

A rear wheel steering device for a vehicle has a steering control mechanism which steers rear wheels of the vehicle on the following formula:

A rear wheel turning mechanism in a four wheel steering system includes a rear wheel turning rod which is connected to the rear wheels of the vehicle and is adapted such that it can be displaced and thereby turn the rear wheels. An electric motor is operatively connected to the rear wheel turning rod and the steering wheel and displaces the rear wheel turning rod, thereby causing the rear wheels to turn in response to operation of the steering wheel. A rear-wheel-neutralizing spring urges the rear wheel turning rod to the neutral position in which the rear wheels are held in the straight-ahead position. A pair of clutches are interposed in series between the electric motor and the rear wheel turning rod and are adapted such that they disconnect the latter from the former, which permits the latter to return to the neutral position under the force of the rear-wheel-neutralizing spring.

Rear wheel turning system

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 for a vehicle consisting of a steering mechanism that includes a steering wheel. A front wheel turning mechanism is 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 is operatively connected to the steering mechanism to turn the rear wheels in response to operation of the steering wheel. A hydraulically operated power assist is connected with the rear wheels turning mechanism. A rear wheels steering ratio changing mechanism is provided for changing the ratio of the turning angle of the rear wheels with respect to the turning angle of the steering wheel. A return mechanism is provided for returning the rear wheels to a neutral position. A valve mechanism drains the oil applied from an oil pump to the power assist mechanism. An engine stop mechanism is provided for stopping the engine. A control mechanism is provided for controlling the valve mechanism to drain the oil when the engine stop mechanism outputs a signal for stopping the engine. A delay mechanism is provided for delaying the drain of the oil applied from the oil pump to the power assist means.

Four-wheel steering apparatus for vehicle

A vehicle four-wheel steering apparatus including a manually operated steering member and front and rear wheel steering mechanisms coupled with the steering member for producing steering movements in the vehicle front and rear wheels. The rear wheel steering mechanism includes a power assist actuated by an oil pump driven by the vehicle engine. A return spring returns the rear wheels to a neutral position when the power assist is off. A steering condition detector detects the condition of the rear steering mechanism. An engine output power increase mechanism increases the engine output power responsive to a control signal for increasing the engine output power when the rear steering mechanism is actuated.

A four-wheel steering system has a front wheel turning mechanism for turning front wheels in response to operation of a steering wheel, a rear wheel turning mechanism for turning rear wheels, a controller for controlling the rear wheel turning mechanism to turn the rear wheels according to preset four-wheel steering characteristics and a relay shaft which is connected to the controller to transmit turning of the front wheels to the controller. The front wheel turning mechanism and the rear wheel turning mechanism are caused to bring the front wheels and the rear wheels to the respective straight-ahead positions while the relay shaft is disconnected from the controller. Then the controller is brought into the state corresponding to the straight-ahead positions of the front and rear wheels on the basis of the preset four-wheel steering characteristics. Thereafter, the relay shaft is connected to the controller.

Method of incorporating four-wheel steering system in vehicle and

A four-wheel steering system for a vehicle in which the rear wheels of a vehicle are turned in response to the turning of the front wheels of the vehicle upon operation of a steering wheel. The rear wheel steering is derived from the front wheel steering by way of a transmission shaft. The transmission shaft is supported rotatably and for sliding movement in the axial direction by way of a bearing fixed on the vehicle body. A stopper ring is fixed on the transmission shaft a short distance forward from the bearing to limit the backward sliding of the transmission shaft.

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Hiroshima, Japan

Hirotaka Kanazawa