Abstract: A vehicle suspension apparatus has suspension units each with a height control fluid spring chamber, fluid supply valves for supplying a fluid from a fluid source to the spring chambers through corresponding supply control valve means, and fluid exhaust valve means for exhausting the fluid from the fluid spring chambers through exhaust control valve means. The supply control valve means are opened only for a predetermined period of time to increase the height by a predetermined distance upon the operation of a high height selection switch, thereby increasing the height to the maximum height.

Abstract: Judgement of a rough road is made when detecting the number of upward and downward movements exceeding the set range of the vehicle height within a predetermined period of time by the vehicle height sensors or when detecting the upward and downward acceleration exceeding the set value within a predetermined period of time by an acceleration sensor. Since a high vehicle height is automatically set as a target vehicle height to control the vehicle height toward the same high vehicle height by the control unit, the minimum ground height of the body is raised to reduce a contact of the body with the surface of the road, thereby improving drivability of a vehicle on a rough road and decreasing damage of the body.

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.