Abstract: A vehicle suspension apparatus has air spring chamber provided at a suspension unit for supporting a rear wheel, air supply means for supplying air to the air spring chamber of the suspension unit for supporting the rear wheel through supply opening and closing valve, air exhaust means for exhausting air from the air spring means of the suspension unit for supporting the rear wheel, a parking brake sensor for detecting the operated state of a parking brake, and a shift position detecting sensor for detecting the shift position of an automatic transmission having a fluid drive unit for transmitting drive power to wheels. The parking brake sensor detects whether or not the parking brake is engaged.

Abstract: A suspension device for automobile performs changing-over of the damping force of a shock absorber and the spring constant of a suspension spring by an output from an acceleration sensor or an output from a road clearance sensor mounted on the vehicle body. The changing operation is not performed by magnitude of an output but is performed only when an output greater that a predetermined level continues for a predetermined time period to avoid unnecessary change-over operations of the suspension characteristic during cruising a rough road.

Abstract: A vehicle suspension apparatus including suspension units each provided for each wheel and having an air spring chamber is disclosed, in which rolling control and vehicle height control are done through control of air to and from the air spring chambers. The driving of a reservoir tank for storing compressed air to be supplied to the air spring chambers, is inhibited until the engine operation has been stabilized after the start of the engine preset level. In this way, the problems in the engine lubrication and idling are solved, and the defficiencies of the starting property of the engine are overcome.

Abstract: The characteristic of the suspension is held to be a soft one when the vehicle is running along a flat surface, while it is automatically switched by the switch unit to a hard one when the cycle period T of vertical vibration of the vehicle height becomes near the cycle of the natural vibration of sprung mass of the suspension at the time of running along a road having an irregular surface or jumping a projection, thereby suppressing the resonance of the vehicle body due to external force applied from the road to improve the comfortability.

Abstract: A vehicle suspension apparatus has a hard/soft switching unit for switching suspension units between a hard state and a soft state, a vehicle velocity sensor for detecting a vehicle's velocity, and control means for receiving a signal from the vehicle velocity sensor and controlling the hard/soft switching unit for holding the suspension units in the soft state when the vehicle's velocity detected by the vehicle velocity sensor is smaller than a switching velocity as a first preset velocity set by the hard/soft switching unit and in the hard state when the vehicle's velocity detected by the vehicle velocity sensor exceeds the switching velocity. The vehicle suspension apparatus further has a switching velocity preset switch for presetting the switching velocity.

Abstract: In a suspension device for automobile having a shock absorber provided with a damping force change-over mechanism and a suspension spring provided with a spring constant change-over mechanism, a power source to perform both the changing-over of the damping force of the shock absorber and the spring constant of the suspension spring depends on a fluid pressure source equipped in the automobile and the fluid pressure from the pressure source is controlled by an electromagnetic valve.

Abstract: A vehicle suspension apparatus including suspension units each provided for each wheel and having an air spring chamber is disclosed. When steering wheel is quickly returned toward the center position at the time of a slalom running, it is detected from the steering angular velocity and vehicle velocity that the vehicle body has begun to be returned to a neutral state, and communication control valves are opened before the reaching of the center position, i.e., before the steering angle reaches an insensitive range. Rolling control thus can be improved without delay in the restoration of the position of the vehicle body even at the time of a high speed slalom running, at which time the steering wheel is repeatedly operated quickly.

Abstract: When an automobile or other vehicle travels over a bump with a suspension in its switchable suspension system kept in a "soft" state, the car body pitches violently. This pitching is reduced by turning the suspension into a "hard" state by increasing the damping capacity of its shock absorber and the spring constant of its air-spring chambers in accordance with a signal supplied from a car-height sensor detecting the compressed or stretched condition of the suspension. The change of the spring constant is executed with the following construction: an auxiliary air-spring chamber resting above a main air-spring chamber surrounding a piston rod, and an air passage within the piston rod for intercommunicating the main and auxiliary air-spring chambers are provided in the system, and the connection and disconnection between the two chambers through the air passage are controlled by the piston rod and a control rod extending in the piston rod.

Abstract: In a switchable suspension system for automobiles and other vehicles, an auxiliary air-spring chamber is provided above a main air-spring chamber in such a manner as to enclose a piston rod so that the spring force of the suspension can be adjusted appropriately. An air passage to connect the two air-spring chambers is provided in the piston rod. The piston rod and a control rod extending inside the piston rod make up a switch valve that controls the opening and closing of the air passage. The air passage of the suspension system is enclosed with a cover to cut off the outward leakage of the noise resulting from the inflow and outflow of air through the air passage that leads from an air compressor to the two air-spring chambers of the suspension system.