Abstract: A tubular hollow member to which torsion about a center line is applied is characterized in performing a partial heat treatment on part of a peripheral wall of the hollow member to make the hardness of an outer portion of the peripheral wall greater than the hardness before heating and greater than the hardness of an inner portion of the peripheral wall, and reduce a residual stress of the inner portion of the peripheral wall.

Abstract: When the difference between the number of revolutions of each tire of a vehicle is judged by the tire air pressure warning device must be made under the condition that the number of revolutions of the four wheels must constantly be detected by different units, and processed at a high speed, and where the vehicle is travelling in a straight line, and at a point in time when all four wheels become at the same condition. In the case that all four wheels do not reach the same condition, the judgment of the difference in the number of tire revolutions at the tire air pressure warning device is prohibited. Also, using the vehicle running conditions, the most suitable tire air pressure judgment is carried out, and various noise generate when the vehicle is travelling do not have any effect, and the tire air pressure abnormality is detected with good accuracy, the detected signal from the wheel velocity sensors is carefully selected, and the reliability and accuracy of the tire air pressure judgment is improved.

Abstract: When the difference between the number of revolutions of each tire of a vehicle is judged by the tire air pressure warning device must be made under the condition that the number of revolutions of the four wheels must constantly be detected by different units, and processed at a high speed, and where the vehicle is travelling in a straight line, and at a point in time when all four wheels become at the same condition. In the case that all four wheels do not reach the same condition, the judgment of the difference in the number of tire revolutions at the tire air pressure warning device is prohibited. Also, using the vehicle running conditions, the most suitable tire air pressure judgment is carried out, and various noise generate when the vehicle is travelling do not have any effect, and the tire air pressure abnormality is detected with good accuracy, the detected signal from the wheel velocity sensors is carefully selected, and the reliability and accuracy of the tire air pressure judgment is improved.

Abstract: A suspension system has a link mechanism, disposed between a wheel support and a car body, for suspending the wheel support from the body so as to allow a wheel, related to steering, to swing about a center axis relative to the body. The link mechanism is caused to change a height of an instantaneous center of a swing of the wheel from the ground according to degrees of turn, such as steered angles, so as to maintain a height of the instantaneous center at a substantially fixed height from the ground.

Abstract: 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.

Abstract: 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.

Abstract: A rear wheel steering system is disposed in a rear wheel steering mechanism and has a power cylinder for generating a power for steering the rear wheels in response to a liquid pressure. The power cylinder is connected to a pump as a source of generating the liquid pressure through a high pressure passage and further to a reservoir tank through a low pressure passage. The high pressure passage is connected to the low pressure passage through a relief passage on the pump side and a relief passage on the power cylinder side, the relief passages being disposed in parallel to each other. The rear wheel steering system is provided with a passage shifting system for closing the relief passages during stationary period of time while opening each of the relief passages during operation and dividing the high pressure passage between the relief passages into sections and with a narrowed passage portion disposed at the relief passage on the power cylinder side.

Abstract: A rear suspension system for supporting dirigible rear wheels of a vehicle consists of left and right rear suspensions each of which includes first and second links which are connected for rotation to the rear wheel support in different positions at their outer ends and to the vehicle body in different positions at their inner ends and a damper which is connected to the vehicle body at its upper end and to the first links at its lower end. The dampers of the left and right rear suspensions are inclined to the corresponding first links so that they transmits force to the first links to generate moments about instantaneous centers of turn of the respective rear wheel supports. The moments are substantially equal to each other and are directed in opposite directions when the rear wheels are held in the straight ahead position.

Abstract: A rear steering control system for a motor vehicle includes an antiskid braking system which controls a braking force in a brake device in a respective wheel in accordance with a deceleration condition of the respective wheel so as to prevent wheel locking in a braking operation. The sytem includes a rear steering control system for establishing a ratio of steering amount of the rear wheels to that of the front wheels as a predetermined steering ratio characteristic. An input device inputs an operation condition of the antiskid braking system and an control condition of the brake device for the respective wheel conducted by the antiskid braking system to the rear steering control system. A device is provided in the system for amending the predetermined steering ratio characteristic in accordance with the control condition of the brake device for the respective wheel when the antiskid braking system is in operation.

Abstract: A front drive vehicle is provided with a four-wheel steering system and a traction control system. A control system for the vehicle detects whether a failure occurs in the traction control system, and causes the rear wheel turning mechanism to turn the rear wheels according to corrected rear wheel turning characteristics when it is determined that a failure occurs in the traction control system. The corrected rear wheel turning characteristics are shifted toward the reverse phase side with respect to the original rear wheel turning characteristics.

Abstract: A vehicle rear suspension system includes a wheel carrying member for rotatably carrying a wheel of a vehicle, three lateral links extending in a transverse direction and connected with the wheel carrying member at their outer ends, and a trailing arm extending in a longitudinal direction. The trailing arm is connected with a body member of the vehicle at front end through a single joint. The trailing arm is formed with biforked portions, at a rear end, extending in the up and down direction. One of the biforked portions is connected with a lower one of the three lateral link and the other of the biforked portions is connected with an upper one of the three lateral links or the wheel carrying member. The number of connecting points or joints between the trailing arm and the wheel carrying member can be reduced with an improved controllability of wheel attitude.

Abstract: A four-wheel-steered vehicle provided with a slip control mechanism which has a slip ratio sensor for detecting the slip ratio of the wheels and controls slip of wheels of the vehicle when the slip ratio of the wheels reaches a first preset value. The four-wheel steering mechanism turns the rear wheels according to first rear wheel turning characteristics in response to turning of the front wheels when the slip ratio of the wheels is smaller than a second preset value which is smaller than the first preset value and turns the rear wheels according to second rear wheel turning characteristics when the slip ratio reaches the second preset value.

Abstract: In a suspension system for a vehicle constructed to change toe angle of wheels when receiving a lateral force, delay means for delaying toe angle change is provided at one of these: a front lateral link, a rear lateral link, and a trailing link. This structure results in a rapid cornering at an initial stage of cornering and a stability of wheels thereafter can be planned.

Abstract: Among two damping devices arranged in series between wheel side members and body side members, while in one damping device spring constant of a spring member is set low and damping coefficient of a damper member is set high, in the other damping device spring constant of a spring member is set high and damping coefficient of a damper member is set low. By this arrangement, difference in damping force between the area of low oscillation frequency and the area of high oscillation frequency can be made large, whereby running stability and comfortableness to ride in can be improved on a high level.

Abstract: A rear suspension system for a four-wheel-steered vehicle has a wheel support which supports a rear wheel for rotation and is connected to a rear wheel turning rod of the rear wheel turning mechanism. A pair of suspension arms are connected to the wheel support and guide the wheel support so that the rear wheel on the wheel support is turned about a kingpin axis in response to displacement of the rear wheel turning rod member. One of the suspension arms includes a so-called I-shaped arm which is connected for rotation to the wheel support at one end and to the vehicle body at the other end, and the kingpin axis intersects the tread of the rear wheel at a point which is offset in the longitudinal direction of the vehicle body from the point at which a side force acts on the rear wheel during cornering. A damping system is connected between the I-shaped arm and the vehicle body.

Abstract: A vehicle rear suspension system includes a wheel carrying member for rotatably carrying a wheel of a vehicle, three lateral links extending in a transverse direction and connected with the wheel carrying member at their outer ends, and a trailing arm extending in a longitudinal direction. The trailing arm is connected with a body member of the vehicle at front end through a single joint. The trailing arm is formed with biforked portions at a rear end extending in the up and down direction. One of the biforked portions is connected with a lower one of the three lateral link and the other of the biforked portions is connected with an upper one of the three lateral links or the wheel carrying member. The number of connecting points or joints between the trailing arm and the wheel carrying member can be reduced with an improved controllability of wheel attitude.

Abstract: A suspension apparatus of a vehicle has a cylinder unit interposed between a sprang weight and an unsprung weight, which changes a ride height of the vehicle body by supplying or discharging an operating liquid through a supply/discharge control valve. The supply/discharge control valve is controlled on the basis of a predetermined condition so as to control a posture of the vehicle body. There are further provided a rebound detecting means for detecting a rebound of each of the wheels and a pressure detecting means for detecting a pressure in the cylinder unit. When the rebound is detected by the rebound detecting sensor to be above a given value, if the pressure detected by the pressure detecting means is continued at a magnitude above a given value for a given period of time, it is judged that the supply/discharge control valve is in trouble.

Abstract: A suspension apparatus of a vehicle has a cylinder unit interposed between a sprang weight and an unsprung weight, which changes a ride height of the vehicle body by supplying or discharging an operating liquid through a supply/discharge control valve. The supply/discharge control value is controlled on the basis of a predetermined condition so as to control a posture of the vehicle body. There are further provided a bump detecting means for detecting a bump of each of the wheels and a pressure detecting means for detecting a pressure in the cylinder unit. When the bump is detected by the bump detecting sensor to be below a given value, if the pressure detected by the pressure detecting means is continued at a magnitude above a given value for a given period of time, it is judged that the supply/discharge control valve is in trouble.

Abstract: A suspension apparatus of a vehicle has a cylinder unit interposed between a sprang weight and an unsprung weight, which changes a ride height of the vehicle body by supplying or discharging an operating liquid through a supply/discharge control valve. The supply/discharge control value is controlled on the basis of a predetermined condition so as to control a posture of the vehicle body. There are further provided a rebound detecting sensor for detecting a rebound of each of the wheels, which occurs further from a state in which the wheel is rebounded, and a pressure detecting sensor for detecting a pressure in the cylinder unit. When it is sensed by the rebound detecting sensor that the rebound occurs further from the rebounding state, if the pressure detected by the pressure detecting sensor is continued in an elevating state for a given period of time, it is judged that the supply/discharge control valve is in trouble.

Abstract: A suspension apparatus of a vehicle has a cylinder unit interposed between a sprang weight and an unsprung weight, which changes a ride height of the vehicle body by supplying or discharging an operating liquid through a supply/discharge control valve. The supply/discharge control value is controlled on the basis of a predetermined condition so as to control a posture of the vehicle body. There are further provided a bump detecting sensor for detecting a bump of each of the wheels, which occurs further from a state in which the wheel is bumped, and a pressure detecting sensor for detecting a pressure in the cylinder unit. When it is sensed by the bump detecting sensor that the bump occurs further from the bumping state, if the pressure detected by the pressure detecting sensor is continued in a lowering state for a given period of time, it is judged that the supply/discharge control valve is in trouble.