Abstract: A vibration damper with integrated level control includes a cylinder in which a hollow piston rod with a piston outfitted with damping valves is guided so as to be axially movable. The piston divides the cylinder into a workspace on the piston rod side and a workspace remote of the piston rod. The workspace on the piston rod side is limited at the end by a piston rod guide, and the workspace remote of the piston rod is connected to a pump space by at least one connection opening in a separating wall. The separating wall supports a hollow rod on which the piston slides and controls the pump operation of the vibration damper. A compensation space receives the damping volume displaced by the piston rod due to a dynamic load, and the piston rod guide is guided in the cylinder so as to be movable axially, and the connection opening in the separating wall is outfitted with a valve that opens in the direction of the work space remote of the piston rod.

Abstract: A check valve includes a housing, a bore, and a liftably movable valve body which is spring-loaded at least after a small axial travel of the valve body and tightly contacts a valve seat. The bore is constructed as a stepped bore, the bore section of smaller diameter having the valve seat, and the bore section of larger diameter receiving the liftably movable valve member. A ball which is held captive by a holding element arranged in the bore is provided as valve body. The valve seat has a contour corresponding to the valve body in the area of the contact surface of the valve body.

Abstract: Damping valve device for a vibration damper, including an actuator that acts on a preliminary stage valve body of a preliminary stage valve. The preliminary stage valve body is arranged in a pre-loading line with a main stage valve body of a main stage valve. The lifting path of the main stage valve body is proportional to the lifting path of the preliminary stage valve body, and the damping characteristic of the damping valve device is influenced by a valve spring arrangement. The preliminary stage valve body controls an adjustable spring compressor that determines the pre-loading of a main stage valve spring is part of the valve spring arrangement.

Abstract: Self-pumping hydropneumatic spring strut includes a working cylinder divided into first and second working spaces by a working piston carried on a hollow piston rod; a high pressure chamber and a low pressure chamber partially filled with hydraulic damping medium, the high pressure chamber having a gas cushion and being connected to the second working space; and a piston pump including a pump rod extending into the hollow piston rod, the pump rod having a bore connected to the low pressure chamber, an end provided with a suction valve inside the hollow piston rod, and a deregulating opening, which is closable as a function of position of the working piston in the working cylinder. An adjustable damping valve located outside the external tube has a first flow connection connected to the first working space, and a second flow connection connected to the second working space and the high pressure chamber.

Abstract: An oil-filled working cylinder is divided into first and second working spaces by a working piston, the first working space being connected to a high pressure chamber. A piston pump includes a pump rod received in a pump cylinder formed by the hollow piston rod, the pump rod having a bore connected to a low pressure chamber via a discharge valve, a distal end provided with a suction valve, and a down-regulating opening connecting the bore to the first working space as a function of the position of the working piston, the pump cylinder being connected to the first working space by an outlet valve. At least one of the valves is a check valve including a housing having a bore, a ball reciprocably guided in the bore by guide ribs, and a resilient retaining element capturing the ball in the bore and spring-loading the ball toward a valve seat.

Abstract: Check valve includes a housing, a bore, and a movable valve body, which is spring-loaded and rests with a sealing action on a valve seat, where the bore is designed as a stepped bore, where the bore with the smaller diameter has the valve seat, and where the bore with the larger diameter holds the movable valve element. The valve body is designed as a ball, which is guided in the bore by at least two guide ribs, and a retaining element in the terminal area of the bore captures the ball and simultaneously spring-loads it.

Abstract: A self-pumping hydropneumatic spring strut with internal leveling control, particularly for motor vehicles, has an outer tube having an oil-filled high-pressure work space in the work cylinder, which high-pressure work space is under pressure by at least one gas cushion which is arranged in a high-pressure chamber and acts as a spring, a second work space on the piston rod side, and a piston which is supported by a hollow piston rod and which is axially displaceable in the work cylinder in a sealed manner, a piston pump which is driven by the spring movement of the vehicle and pumps oil out of a low-pressure chamber into the work space connected to the high-pressure chamber and which comprises a pump rod and a pump cylinder which is formed by the hollow piston rod, and the high-pressure chamber can be connected to the atmosphere by a flow connection which is arranged in the piston rod guide and has a closing element.

Abstract: A vibration damper with integrated level control includes a cylinder in which a hollow piston rod with a piston outfitted with damping valves is guided so as to be axially movable. The piston divides the cylinder into a workspace on the piston rod side and a workspace remote of the piston rod. The workspace on the piston rod side is limited at the end by a piston rod guide, and the workspace remote of the piston rod is connected to a pump space by at least one connection opening in a separating wall. The separating wall supports a hollow rod on which the piston slides and controls the pump operation of the vibration damper. A compensation space receives the damping volume displaced by the piston rod due to a dynamic load, and the piston rod guide is guided in the cylinder so as to be movable axially, and the connection opening in the separating wall is outfitted with a valve that opens in the direction of the work space remote of the piston rod.

Abstract: A bellows for hydraulic, hydropneumatic, or pneumatic piston-cylinder units, especially for vibration dampers or MacPherson strut units for motor vehicles, is located between the end of a piston rod and a cylinder, and covers the part of the piston rod which projects out from the cylinder to provide protection against dirt and/or damage. An interior space of the bellows undergoes a change in volume as a result of the relative movement of the piston and cylinder. The end area of the piston rod distal from the cylinder includes at least one flow connection leading to the interior of the bellows. The flow connection allows an incoming and/or outgoing flow of air. The end area of the piston rod, i.e., the end which passes through a mounting bearing connecting the piston-cylinder unit to the body of the vehicle, is provided with a flow connection connecting the interior space of the bellows to the atmosphere.

Abstract: A piston-cylinder assembly has a working piston attached to a piston rod and dividing a working cylinder into two working spaces. An external reservoir partially filled with damping medium is provided outside the piston-cylinder assembly and is connected to one of the working spaces by a connecting pipe. The piston-cylinder assembly is provided with a stepped bore for receiving the connecting pipe, in the larger-diameter part of which a seal is held in place by the connecting pipe.

Abstract: A wheel suspension includes a working cylinder, a main spring in parallel with the working cylinder, and a piston rod extending from the working cylinder and having a longitudinal axis, the piston rod having fixed thereto a piston and a mount for fixing the piston rod against movement with respect to a vehicle body. The piston is mounted with freedom of axial movement in an adjusting cylinder, the piston dividing the cylinder into a space above the piston and a space below the piston, and an additional spring is located on the longitudinal axis for supporting the adjusting cylinder against the working cylinder. A shut-off element is located in a flow connection connecting the space above the piston to the space below the piston, whereby movement of the piston in the adjusting cylinder can be blocked when the vehicle rolls.

Abstract: A check valve includes a housing, a bore, and a liftably movable valve body which is spring-loaded at least after a small axial travel of the valve body and tightly contacts a valve seat. The bore is constructed as a stepped bore, the bore section of smaller diameter having the valve seat, and the bore section of larger diameter receiving the liftably movable valve member. A ball which is held captive by a holding element arranged in the bore is provided as valve body. The valve seat has a contour corresponding to the valve body in the area of the contact surface of the valve body.

Abstract: A suspension system for motor vehicles with a level control for adjusting a predetermined height of the vehicle body is configured with at least one piston-cylinder unit which is provided with a work cylinder, a piston rod and a damping piston having damping valves, a pump of an oil reservoir, corresponding inlet lines and outlet lines from the oil reservoir, and corresponding inlet lines and outlet lines from the oil reservoir to the piston-cylinder unit, and vice versa, and the pump is configured with a pump piston and a drive unit. The piston-cylinder unit and the pump are constructed as separate subassemblies which are manufactured independently beforehand, and at least the piston-cylinder unit is filled with damping medium before the two subassemblies are mounted.

Abstract: A self-pumping hydropneumatic spring strut includes an oil-filled working cylinder which is divided into two working spaces by a working piston carried by a hollow piston rod. Two high-pressure chambers connectable to the cylinder in such that the piston rod is selectively supported in both directions of movement either on a gas cushion provided by the first high-pressure chamber, the second high-pressure chamber, or both high-pressure chambers. Further, the spring strut includes a piston pump driven by the movements of the piston rod and for conveying oil from a low-pressure chamber to the working space which is connected to at least one of the high-pressure chambers. Moreover, a control channel connects the working space, which is connected to at least one of the high-pressure chambers, to the low-pressure chamber via a control opening, which can be closed as a function of the position of the working piston in the working cylinder.

Abstract: A self-pumping hydropneumatic spring strut with internal leveling control, particularly for motor vehicles, has an outer tube having an oil-filled high-pressure work space in the work cylinder, which high-pressure work space is under pressure by at least one gas cushion which is arranged in a high-pressure chamber and acts as a spring, a second work space on the piston rod side, and a piston which is supported by a hollow piston rod and which is axially displaceable in the work cylinder in a sealed manner, a piston pump which is driven by the spring movement of the vehicle and pumps oil out of a low-pressure chamber into the work space connected to the high-pressure chamber and which comprises a pump rod and a pump cylinder which is formed by the hollow piston rod, and the high-pressure chamber can be connected to the atmosphere by a flow connection which is arranged in the piston rod guide and has a closing element.

Abstract: A self-pumping hydropneumatic spring-damper unit with internal leveling control is provided. The spring-damper unit has an oil-filled work cylinder under pressure by gas cushions. A damping piston is displaceable in the work cylinder and arranged at the end of a hollow piston rod whose hollow space serves to receive a pump by means of a pump rod fastened to the work cylinder. Damping medium is sucked out of a reservoir space when the piston rod moves outward and is conveyed into the work space when the piston rod moves inward. The pump rod has a control opening and, at a distance therefrom, an outlet bore for pressure equilibrium between work spaces in the work cylinder. At least one pressure-dependent throttle point is provided in the pump space between the high-pressure and low-pressure gas cushions. A first flow connection in the pump rod provided with at least one check valve connects the low-pressure gas cushion to the pump space.

Abstract: A piston-cylinder unit configured to provide a level adjustment function based on internal pressure includes a working cylinder, a piston rod, a working piston mounted on the piston rod, and fastening elements coupled to the piston rod and the working cylinder. Each fastening element is configured to attach to a chassis or a vehicle body. One of the fastening elements is mountable with freedom of axial movement relative to the piston rod or the working cylinder and includes a cylindrical bore and a chamber disposed between the cylindrical bore and an end surface of the piston rod or a journal of the working cylinder. The end surface of the piston rod or the journal includes a first effective pressure-actuated cross-sectional area approximately the same as a second effective pressure-actuated cross-sectional area of the piston rod. The first and the second cross-sectional areas are actuated by system pressure.

Abstract: Presented is a piston-cylinder unit. The piston-cylinder unit includes an outer tube defining a cavity, a working cylinder disposed in the cavity of the outer tube and filling only a portion of the cavity. The unfilled portion of the cavity is a compensating space. The compensating space is divided into an area filled with a damping medium and an area filed with a gas. The piston-cylinder unit further includes a piston rod that includes a damping piston. The piston rod is disposed in the working cylinder and has freedom of axial movement, and is configured to displace the gas. The piston-cylinder unit further includes a reservoir that has a variable volume configured for actuating the compensating space.

Abstract: Self-pumping hydropneumatic spring strut includes a working cylinder divided into first and second working spaces by a working piston carried on a hollow piston rod; a high pressure chamber and a low pressure chamber partially filled with hydraulic damping medium, the high pressure chamber having a gas cushion and being connected to the second working space; and a piston pump including a pump rod extending into the hollow piston rod, the pump rod having a bore connected to the low pressure chamber, an end provided with a suction valve inside the hollow piston rod, and a deregulating opening, which is closable as a function of position of the working piston in the working cylinder. An adjustable damping valve located outside the external tube has a first flow connection connected to the first working space, and a second flow connection connected to the second working space and the high pressure chamber.

Abstract: Self-pumping hydropneumatic suspension strut unit with internal level control, with an oil-filled working cylinder subject to the pressure of gas cushions and with a damping piston, which is free to slide inside the cylinder and is mounted at the end of a hollow piston rod, the cavity of which serves as a pump cylinder for a pump rod attached to the working cylinder. Oil is drawn from a reservoir space when the piston rod travels outward, whereas the oil is conveyed into the working space when the piston rod travels inward. The pump rod passes through the end wall of the working space and is held axially in position by an end-mounted disk formed as a Belleville washer, which acts as a universal joint for the rod. The disk engages in a groove in the pump rod and is held in place by its outer circumference axially between the working cylinder and the end wall of the working cylinder.