Mazda Motor Corporation

Toyo Kogyo Co., Ltd.

Kenichi Watanabe

Osamu Kameda

Mitsuru Nagaoka

Kaoru Sotoyama

Haruyuki Taniguchi

Eiji Nishimura

Takashi Sumimoto

Shin Takehara

Akihiko Miyoshi

Eizi Nishimura

Hitoshi Inoue

Hiroo Shimoe

Kazutoshi Nobumoto

Takeshi Edahiro

Takao Kijima

Yasunari Nakayama

Shoichi Kamimura

Hideshi Hiruta

Kazuo Katayama

Manabu Hiketa

Shunsuke Kawasaki

Shoich Kamimura

A four-wheel drive vehicle has a center differential which transmits the output torque of a power plant to both front and rear wheels in such a manner as to permit the front and rear wheels to rotate at different speeds. A differential control system has a differential rotation limit member which acts on the center differential to limit differential rotation of the front and rear wheels to a degree which is increased as the difference in rotational speed between the front and rear wheels increases. The degree of limitation on the differential rotation of the front and rear wheels is changed according to a predetermined characteristics which nullifies the degree of limitation in a range where the difference in rotational speed is relatively small and provides a gain in a range where the difference in rotational speed is relatively large. The gain is changed according to a factor which governs the running condition of the vehicle.

Differential control system for four-wheel drive vehicle

A four-wheel drive vehicle has a center differential which transmits the output torque of a power plant to both front and rear wheels in such a manner as to permit the front and rear wheels to rotate at different speeds. A differential control system has a differential rotation limit member which acts on the center differential to limit differential rotation of the front and rear wheels to a degree which is determined according to the difference in rotational speed between the front and rear wheels. The degree of limitation on the differential rotation of the wheels is determined according to the difference in rotational speed between the front and rear wheels based on first characteristics when the rotational speed of the front wheels is higher than that of the rear wheels and based on second characteristics when the rotational speed of the rear wheels is higher than that of the front wheels. The first and second characteristics are set separately from each other.

A four wheel drive system for a vehicle includes comprising a power plant for producing a driving force, a front wheel driving mechanism for transmitting the driving force to drive right and left front wheels, a rear wheel driving mechanism for transmitting the driving force to drive right and left rear wheels, and right and left wheel clutches provided in one of the driving mechanisms for controlling the amount of the driving force transmitted to the wheels. A cut-off clutch is provided for controlling the driving force transmitted to the wheels of the one of the driving mechanisms, and a control device causes the cut-off clutch to engage before the wheel clutch is engaged. The driving force is transmitted sequentially rather than instantly from the cut-off clutch, the wheel clutches and to the wheels so as to suppress the torque shock creative in connection with a change in the drive condition.

Four wheel drive system

A four wheel drive system of a vehicle including a power plant for producing driving force, has a front wheel driving mechanism for transmitting the driving force to drive a right and left front wheels and rear wheel driving mechanism for transmitting the driving force to drive right and left rear wheels. Right and left wheel clutches provided in one of the driving mechanisms for control the amount of the driving force transmitted to the wheels, and steering angle detecting device detects a steering angle of a steering wheel. A control device increases torque distribution for the rear wheel driving mechanism in a cornering condition of the vehicle as a steering angle change rate is increased. The system provides the vehicle with a desirable torque distribution during a cornering operation so that improved cornering property is obtained.

A drive control system of a four-wheel drive vehicle has a differential device interposed between front and rear wheels and a differential restricting device mounted to the differential device. The differential restricting device is subjected to feedback control so as for the wheels to reach a target slip ratio. In this control, a control target value is given by way of slip ratios of the wheels and the target slip ratios are then converted into a wheel speed difference between the front and rear wheels. The feedback control of the differential restricting device is performed by comparing the target wheel speed difference with an actual wheel speed difference between the front and rear wheels.

Drive control system of four-wheel drive vehicle

Disclosed is a four wheel drive vehicle with four wheels drivable, which is provided with a first slip control apparatus for reducing a driving force to the wheels by operating a brake mounted on each of the wheels and with a second slip control apparatus for reducing a driving force to the wheels by reducing the engine output. Operation of only the first slip control apparatus or both the first and second slip control apparatuses is selectively carried out in accordance with the number of wheels which are detected to be slipping in an amount greater than a given degree of slippage. Particularly when such slipping wheels are two, the slip control is conducted by operating only the first slip control apparatus or both the first and second slip control apparatuses in accordance with control modes predetermined on the basis of six combinations in which such two slipping wheels out of the four wheels are combined with each other.

Slip control apparatus for a four wheel drive vehicle

A suspension system for a vehicle comprises a wheel supporting structure provided for supporting a steerable wheel rotatably and composed of upper and lower support members, an upper suspension member extending from a body of the vehicle for connecting the upper support member with the body in such a manner that the upper support member is movable up and down in relation to the body, a lower suspension member extending from the body for connecting the lower support member with the body in such a manner that the lower support member is movable up and down in relation to the body, and an elastic joint structure provided for coupling the lower support member with the upper support member so that the lower support member is engaged with the upper support member only through the elastic joint structure and constituted to be relatively flexible in a vehicle longitudinal direction and relatively hard in a vehicle transverse direction.

Suspension systems for vehicles

A friction detecting device comprising running condition detector for detecting a running condition of a vehicle including a lateral acceleration acting on a gravity center of the vehicle, steering angle detector for detecting steering angle of front and rear wheels of the vehicle, vehicle speed sensor, memory for storing stability factors of the vehicle including a vehicle weight, respective distances between the gravity center and front and rear axles, cornering powers acting on the front and rear wheels at a standard condition and a yawing moment of inertia, control unit for obtaining a frictional coefficient .mu. of a road surface on which the vehicle is running by employing a following formula;

Friction detecting device for vehicles

A vehicle four wheel steering system including a front wheel steering mechanism for steering the front wheels in response to an operation of a manually operated steering member, a rear wheel steering mechanism for steering rear wheels in response to a steering movement of the front wheel. A control unit is provided for changing the steering ratio of the rear wheel steering angle to the front wheel steering angle in accordance with the vehicle speed. The steering ratio is further modified so that the rear wheel steering angle is added with a modification angle in the direction opposite to the direction of steering of the front wheel, the modification angle being increased in response to an increase in the side force on the vehicle.

Control in a vehicle four wheel steering system

A vehicle suspension system including a hydraulic cylinder and a gas spring having a gas chamber and a hydraulic chamber which is connected with the hydraulic cylinder. The hydraulic cylinder is located between the vehicle body and the wheel to support the body on the wheels. A control valve is provided for controlling the supply of hydraulic pressure to the cylidner in accordance with a signal from a control unit. The control unit receives a detection signal from a detector which detects the pressure in the cylinder and produces a control signal in accordance with a transfer function H(s)=R.times.S/(1+R.times.S).

Vehicle suspension system having variable suspension properties

The suspension system of the present invention comprises support means installed between a wheel and the vehicle body exerting suspension force which can be changed irrespective of relative displacement between the wheel and the vehicle body. According to low frequency components of a parameter which respresents changing condition of the relative displacement, the support means is controlled to exert a suspension force in such a way that the relative displacement can be suppressed. Such parameters include the relative displacement and the rate of the change thereof. According to the present invention, suspension characteristics can be maintained to maintain riding qualities and rolling and pitching properties in a preferable condition throughout all running conditions.

Vehicle suspension system

A torque control system comprising a torque transmitting device interposed in a torque transmitting path through which drive torque is transmitted from a power plant to wheels, a selecting device for selecting a single control property among a plurality of control properties in which the amount of drive torque from a power plant to wheels through the torque transmitting device is determined corresponding to drive conditions of a vehicle, and a torque control unit for controlling the amount of the torque transmitted through the torque transmitting device in accordance with the control property selected by the selecting device so that the torque distribution for the rear wheels can be maintained at a desirable value in accordance with drive condition of the vehicle.

Torque control system for vehicles

A vehicle driving system including a hydraulic clutch having a plurality of friction members which are adapted to be forced into engagement with each other by a hydraulic pressure applied to a piston in the clutch. A control unit is provided to detect a condition of heat generation in the hydraulic clutch and relieving the hydraulic pressure to the clutch or increasing the hydraulic pressure to the hydraulic clutch when the condition of heat generation is out of an allowable limit.

Driving system for a four-wheel drive vehicle

A mounting system for a vehicle engine including mounting units located at the opposite sides of the engine output shaft. The mounting unit includes a hydraulic chamber filled with hydraulic liquid. The hydraulic chamber of one unit is connected with that of the other unit through a conduit which may be provided with a variable orifice or a valve. The variable orifice or the valve is operated so that the fluid flow through the conduit is restricted or cut-off under a specific rolling frequency range.

Hydraulic mounting system for a power unit

A torque control arrangement for a four-wheel-drive vehicle comprises a fluid torque transmitting device disposed in a front or rear torque transmitting path and operative to vary torque transmitted therethrough in response to a difference between input speed and output speed thereof, a clutch device provided in series to the fluid torque transmitting device, front and rear speed reduction devices for determining a final drive ratio in the front torque transmitting path and a final drive ratio in the rear torque transmitting path, respectively, first and second speed sensors for detecting the input speed and the output speed of the fluid torque transmitting device, respectively, and a control unit operative to disengage the clutch device when a speed difference obtained by substracting the output speed of said fluid torque transmitting device from the input speed of said fluid torque transmitting device is reduced to a range of positive values, the upper limit of which is not greater than a predetermined small value close to zero.

Growing community of inventors

Hiroshima, Japan

Kenichi Watanabe