The present exemplary embodiments relate to a variable damping force shock absorber in which variable valves each capable of varying a damping force during compression and rebound strokes are installed inside a cylinder, and thus, a volume of an apparatus is reduced to easily secure an installation space and prevent interference with peripheral components.

A vehicle height adjustment apparatus according to one embodiment includes a spring, a spring-length changing unit, a first valve, a control valve and a second valve. The spring-length changing unit changes a length of the spring in accordance with an amount of oil in a jack chamber that accommodates the oil. The first valve opens and closes a first communication path in which the oil supplied from a pump is oriented toward a reservoir chamber that stores the oil. The control valve opens and closes a discharge flow path oriented toward the reservoir chamber from a chamber that accommodates the oil to close the first valve. The second valve opens and closes a second communication path in which the oil supplied from the pump is oriented toward the jack chamber when the first valve is closed.

A hydraulic damper for a vehicle including a main tube. A first piston assembly is slideably disposed in the main tube and axially divides the main tube into a rebound chamber and a primary compression chamber. A hydraulic compression stop assembly is disposed in the primary compression chamber and includes a narrowed section extending between an open end and a closed end. A second piston assembly is slideably disposed in the narrowed section and is coupled with the first piston assembly. The second piston assembly has a piston tube that extends between an opened end and a shut end. A displaceable partition is slideably disposed in the piston tube. A first auxiliary compression chamber is defined between the partition and the closed end of the narrowed section. A second auxiliary compression chamber is defined between the partition and the shut end of the piston tube.

A hydraulic device includes a tubular housing containing a rod to which a plunger is rigidly secured that separates an upper chamber and a lower chamber both filled with a hydraulic fluid such that the plunger and the rod move together in a relative manner axially inside the tubular housing, thereby moving the hydraulic fluid from one chamber to the other and varying the volumes thereof. The hydraulic device further includes a spring that operates under compression resisting the movement of the plunger in one direction when the plunger moves toward a maximum extension position of the hydraulic device. The hydraulic device also includes an open elastic ring, the ends of which define an adjustable intermediate passage for the hydraulic fluid in order to adjust damping at the end of maximum extension of the hydraulic device and in other relative positions.

A hydraulic shock absorber equipped with a leading stop, comprising a piston (4) sliding inside a body (2) for the purpose of shock absorption. The piston (4) moves a sleeve (10) which is disposed towards the front and provided with axially-distributed holes (18), and, at the shock absorber end-of-stroke, the sleeve fits around a stationary chamber (12) that gradually closes the holes (18), thereby reducing the cross-section through which fluid can flow into the sleeve (10). The chamber (12) comprises additional holes (40a, 40b) and said chamber (12) receives a moving gate (42) therein, which, depending on its position, either closes or opens the additional holes (40a, 40b).

A spring-damper system for a wheel suspension of a motor vehicle comprise a support spring of a spring constant k.sub.T and a damper acting in parallel to the support spring. A spring element is arranged in series with the support spring and can be controlled by means of a controller in such a way that a total spring constant k.sub.G of the spring-damper system can be varied.

A position-and-velocity dependent hydraulic damper is provided. The hydraulic damper has piston valve fixed to a tip of a piston rod, a base valve, and a reservoir chamber. The base valve has a compression side port. Between a first valve and the base valve, a first spiral spring is provided, and between the first valve and the piston valve, a second spiral spring is provided. The compression side port is closed by the first valve around the maximum compression state, reducing the flow rate of oil to the reservoir chamber. A second valve passing through the centers of the first valve and the base valve adjusts the flow rate of the oil to the reservoir chamber with a pressure equal to or higher than a prescribed level of an oil chamber.

A hydraulic damper including a tube defining a chamber. The tube has a main section and a narrowed section. A main piston assembly is disposed in the main section and connected to a piston rod. A resisting mechanism is fixed to the piston rod. A secondary piston is moveable into the narrowed section. An inner surface of the secondary piston defines at least one radially internal channel. The piston rod defines an annular recess. The secondary piston includes a locking mechanism axially slideable within the annular recess. The secondary piston is axially moveable between a hydraulic stop engagement stroke wherein the secondary piston engages the resisting mechanism and restricts the flow of fluid through the radially internal channel, and a hydraulic stop disengagement stroke wherein the secondary piston is spaced from the resisting mechanism and allows the flow of fluid through radially internal channel.

A shock absorber includes an extension-side damping valve, which provides an extension-side damping force, a first bypass passage, which bypasses the extension-side damping valve, a first pressure chamber, a first free piston, and a first spring, which are disposed in the first bypass passage, a contraction-side damping valve, which provides a contraction-side damping force, a second bypass passage, which bypasses the contraction-side damping valve, and a second pressure chamber, a second free piston, and a second spring, which are disposed in the second bypass passage.

A passive ride height adjuster mechanism includes a piston and cylinder acting on a main suspension spring at one or more locations around the chassis of a race car; with the piston-cylinder having adjustable length or travel; a hydraulic or pneumatic pressurization system mounted in the chassis is connected to the piston-cylinder; a signal from a timer or sensor on the chassis that signals the pressurization or depressurization of the piston-cylinder which affects the chassis ride height.