A vehicle height adjustment device includes a spring having one end supported on a vehicle body side and another end supported on a wheel side. An adjustor includes an accommodation chamber accommodating fluid and adjusts a length of the spring in accordance with an amount of fluid in the accommodation chamber. A storage chamber stores fluid. A guide passage guides fluid from the accommodation chamber to the storage chamber. An actuator includes an operation rod to press a push rod. A valve body closes the guide passage when seated on a seat and opens the guide passage when pressed and detached from the seat by the push rod. A press member includes a contact portion and a shaft. The press member presses and seats the valve body on the seat. An accommodation member accommodates the valve body and the contact portion. A support member supports the shaft movably.

A vehicle height adjustment apparatus includes a control device. The control device controls the opening degree of the solenoid valve to allow a movement amount of the support member to reach a movement amount target value that corresponds to the vehicle height set in advance, in accordance with the weight applied to the vehicle. The control device controls the opening degree of the solenoid valve to change the movement amount of the support member based on a difference between a value based on the information related to the vehicle height and a vehicle height-related target value, on condition that the movement amount of the support member reaches the movement amount target value and the value based on the information related to the vehicle height obtained by the information obtaining device does not reach the vehicle height-related target value that corresponds to the vehicle height set in advance.

A vehicle height adjustment apparatus includes a control device. The control device controls the opening degree of the solenoid valve to allow a movement amount of the support member to reach a movement amount target value that corresponds to the vehicle height set in advance, in accordance with the weight applied to the vehicle. The control device controls the opening degree of the solenoid valve to change the movement amount of the support member based on a difference between a value based on the information related to the vehicle height and a vehicle height-related target value, on condition that the movement amount of the support member reaches the movement amount target value and the value based on the information related to the vehicle height obtained by the information obtaining device does not reach the vehicle height-related target value that corresponds to the vehicle height set in advance.

A hydropneumatic suspension strut includes a piston-cylinder unit with a first gas spring and a second carrying spring. The gas spring and the carrying spring are connected in parallel and have an identical working direction. The suspension strut is adjustable to at least two level positions. The second carrying spring has a spring rate that increases as the effective length of the suspension strut decreases.

A vehicle height adjustment device includes front forks, a rear suspension, a weight estimation unit, and a front wheel-side target movement amount determination unit. The front fork includes a front wheel-side suspension spring and a front wheel-side support member, which supports one end of the front wheel-side suspension spring, and moves toward another end of the front wheel-side spring to change the front wheel-side suspension spring length. The rear suspension includes a rear wheel-side suspension spring and a rear wheel-side support member, which supports one end of the rear wheel-side suspension spring, and moves toward another one end of the rear wheel-side spring to change the rear wheel-side suspension spring length. The weight estimation unit estimates a weight applied to a vehicle. The front wheel-side target movement amount determination unit decreases, a movement amount of the front wheel-side support member as the estimated weight increases.

A vehicle suspension system may include hydraulic actuators, first and second conduits, and first and second switch valves. Each actuator includes a cylinder and a piston that divides an interior of the cylinder into compression and rebound chambers. First and third ports of each cylinder are openings to the rebound chamber. Second and fourth ports of each cylinder are openings to the compression chamber. The first conduit connects the third port of a first actuator with the fourth port of a second actuator. The second conduit fluidly connects the third port of the second actuator with the fourth port of the first actuator. The first switch valve is connected to the first and second ports of the first one of the hydraulic actuators. The second switch valve is connected to the first and second ports of the second one of the hydraulic actuators.

A rinsing system includes: a pump control module configured to, when a hydraulic line is connected to a port that is fluidly connected to a hydraulic line of a suspension system, selectively operate a hydraulic fluid pump of the suspension system and pump hydraulic fluid from a hydraulic fluid tank of the suspension system through the hydraulic fluid pump toward the hydraulic line; and a valve control module configured to, when the hydraulic line is connected to the port and the hydraulic fluid pump is pumping hydraulic fluid, open valves of the suspension system and fluidly connect the hydraulic fluid pump with the hydraulic line.

A rinsing system includes: a pump control module configured to, when a hydraulic line is connected to a port that is fluidly connected to a hydraulic line of a suspension system, selectively operate a hydraulic fluid pump of the suspension system and pump hydraulic fluid from a hydraulic fluid tank of the suspension system through the hydraulic fluid pump toward the hydraulic line; and a valve control module configured to, when the hydraulic line is connected to the port and the hydraulic fluid pump is pumping hydraulic fluid, open valves of the suspension system and fluidly connect the hydraulic fluid pump with the hydraulic line.

A vehicle wheel suspension has a hydraulic adjustment system for the base of a support spring provided between a wheel-guide component and the vehicle structure. The suspension includes a piston pump which is driven via a relative movement of the vehicle structure in relation to a wheel-guiding component and intended for conveying hydraulic medium through a return valve into a hydraulic chamber provided at the spring base, as well as a pressurized compensation volume for providing hydraulic medium. Preferably, the piston pump has a pump cylinder and a pump piston guided such that it can move relative to the former and a return channel connected to the hydraulic chamber feeds into the pump cylinder in such a way that the feed opening is blocked or released by the pump piston in a position-dependent manner, wherein hydraulic medium can flow via the released feed opening, out of the hydraulic chamber, through the pump cylinder and into the compensation volume.

A vehicle wheel suspension has a hydraulic adjustment system for the base of a support spring provided between a wheel-guide component and the vehicle structure. The suspension includes a piston pump which is driven via a relative movement of the vehicle structure in relation to a wheel-guiding component and intended for conveying hydraulic medium through a return valve into a hydraulic chamber provided at the spring base, as well as a pressurized compensation volume for providing hydraulic medium. Preferably, the piston pump has a pump cylinder and a pump piston guided such that it can move relative to the former and a return channel connected to the hydraulic chamber feeds into the pump cylinder in such a way that the feed opening is blocked or released by the pump piston in a position-dependent manner, wherein hydraulic medium can flow via the released feed opening, out of the hydraulic chamber, through the pump cylinder and into the compensation volume.