Zf Friedrichshafen Ag

Fichtel & Sachs Ag

Zf Sachs Ag

Mannesmann Sachs Ag

Boge Ag

Boge Gmbh

Hubert Beck

Werner Kuchheuser

Norbert Ackermann

Holger Kirchner

Heinz Knecht

Klaus Schmitz

Dieter Eulenbach

Alfred Preukschat

Ewald Kohberg

Karl-Heinz Lohr

Thomas Meyer

Bernd Wilms

Norbert Sommer

Matthias Molitor

Willi Wortmann

Albrecht Nachtigall

Hans-Dieter Eulenbach

Wilhelm Wortmann

Burkard Bender

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.

Vibration damper with integrated level control

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.

Method of manufacturing a check valve

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.

Self-pumping hydropneumatic spring strut with internal level control

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.

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.

Check valve

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. The piston rod is sealed in the piston rod guide by means of at least two seals which are arranged one behind the other axially. A flow connection extends from between two adjacent seals into the low-pressure chamber. The flow connection is acted upon by a check valve which passes damping medium only in direction of the low-pressure chamber.

Self-pumping hydropneumatic spring strut

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.

Bellows for hydraulic, hydropneumatic, or pneumatic piston-cylinder units

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.

Piston-cylinder assembly

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.

Wheel suspension

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.

Suspension system for motor vehicles

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.

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. The disk has a slot to accept the pump rod, the first area of this slot having a diameter corresponding to the base of the groove, whereas the second area has a diameter corresponding to the outside diameter of the pump rod.

Self-pumping hydropneumatic suspension strut unit

A boot for a hydraulic, hydropneumatic or pneumatic piston-cylinder unit, in particular for vibration dampers or spring struts for vehicles, covers a portion of a piston rod that projects from the cylinder of the piston-cylinder unit. To protect against dirt and/or damage, the boot is arranged between the end of the piston rod and the cylinder. The interior space of the boot undergoes a change in volume due to the relative movement of the piston rod and cylinder with respect to one another. At least one flow connection is provided which leads to the interior space of the boot and allows for air flow in and/or out of the interior space. The at least one flow connection is at least partly covered by an area of the boot.

Boot for hydraulic, hydropneumatic or pneumatic piston-cylinder units

A self-pumping hydropneumatic spring strut unit includes a working cylinder filled with oil under pressure and a piston and rod unit displaceable in the cylinder so as to define two working spaces in the cylinder, and high-pressure and low pressure chambers surrounding the cylinder. The strut unit further has a piston pump operable to transport a working medium from the low-pressure chamber into the one working space which is in flow communication with the high-pressure chamber. The piston pump has a cylinder defined by the inner surface of the piston rod unit, and a hollow pump rod coupled to the working cylinder and having a flow channel in communication with the low-pressure chamber. The flow channel has a deregulating opening on the working space and a throttle in flow communication with the deregulating opening. A filter device protects the throttle from impurities carried by the oil during flow from the deregulating opening to the low pressure chamber.

Self-pumping hydropneumatic spring strut unit

Spring strut unit for suspension systems of motor vehicles with a fastening connection on the body side and another fastening connection on the wheel side; with a helical spring supported between the body and the wheel; and with a vibration damper installed between the body-side fastening connection and the wheel-side fastening connection. The vibration damper includes a working cylinder, a damping piston attached to a piston rod, damping valves installed in the damping piston, and a compensating space. The helical spring can be pretensioned by a ring-shaped cylinder, which can be actuated by a hydraulic medium. A pump rod is mounted in a permanent axial position in the working cylinder of the vibration damper and cooperates with a cavity in the piston rod to form a pump space. Axial movements of the piston rod cause damping medium to be conveyed through flow connections from one of the working spaces of the working cylinder via the pump space and through a flow connection of the pump rod into the ring-shaped cylinder.

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Eitorf, Germany

Hubert Beck