Adjustable spring support

Adjustable spring support comprising a spring plate which is axially adjustable by an annular actuator, wherein the actuator is supplied with pressure medium via a pressure medium supply system, wherein the annular actuator has a pressure medium connection to the pressure medium supply system, and the housing of the actuator is connected directly to a housing of the pressure medium supply system.

PRIORITY CLAIM

This is a U.S. national stage of application No. PCT/EP2016/057999, filed on Apr. 12, 2016. Priority is claimed on the following application: Country: Germany, Application No.: 10 2015 208 787.5, filed: May 12, 2015; the content of which is incorporated in its entirety herein by reference.

FIELD OF THE INVENTION

The invention is directed to an adjustable spring support with an actuator and a pressure medium supply system.

BACKGROUND OF THE INVENTION

Known from DE 32 23 195 A1 is an adjustable spring support which has a first spring plate and a second spring plate, wherein the distance between the two spring plates can be varied by an actuator which can be actuated by pressure medium for specific preloading of a supporting spring arranged between the two spring plates in order to achieve a required carrying capacity.

A hydraulic medium is used as pressure medium. A pump conveys pressure medium from a supply receptacle to a cylinder of the actuator. A piston which is connected to one of the two spring plates is slidingly mounted in the cylinder.

As can be seen from the drawing, there is a conduit system between the pump, a storage and the actuator. This division of components has the advantage that the total system can be distributed in a vehicle and, in so doing, individual components such as the pump or the storage can also be positioned farther apart from one another in a vehicle. This increases the expenditure on conduits and assembly as well as the risk of leaks.

Further, at least one flow valve is required for each vehicle wheel to enable adjustment of the required vehicle body level or preloading of the supporting spring via the spring support.

It is an object of the present invention to realize an adjustable spring support with a pressure medium system which can be assembled in a simple manner.

SUMMARY OF THE INVENTION

This object is met in that the annular actuator has a pressure medium connection to the pressure medium supply system, and the housing of the actuator is connected directly to a housing of the pressure medium supply system.

Hoses and exposed couplings can be dispensed with as a result of arranging the entire pressure medium system as a constructional unit. Further, the overall assembly is simplified. For example, if a plurality of spring supports are used in a chassis, then one flow supply connection and one CAN-bus connection are sufficient to achieve the required function.

The housing of the pressure medium supply system carries at least one pump, a pump drive and a supply receptacle. Accordingly, hose connections which are prone to leakage can be dispensed with.

In a further advantageous embodiment, the housing of the actuator is fastened to an outer cylinder of a vibration damper. The housing of the pressure medium supply system is also fastened to the outer cylinder via the housing of the actuator.

According to an advantageous embodiment, the housing of the pressure medium supply system is arranged so as to be radially offset with respect to the longitudinal axis of the outer cylinder. “Radially offset” can mean that the main axes of the vibration damper and of the pressure medium supply system extend paraxially but also so as to be skew with respect to one another.

The supply receptacle is preferably arranged above the pump so as not to additionally increase the required pumping outputs.

Further, it can be provided that an annular actuator housing and the housing of the pressure medium supply system are formed integrally. The two housings can be combined in a forged, cast or even extruded component part.

A particularly slender actuator is achieved when the outer cylinder of the vibration damper forms an inner wall of a pressure medium chamber of the actuator.

The actuator is supported on a radial step of the outer cylinder of the vibration damper so that a supporting spring which is as short and, therefore, as light as possible can be used. The step can be formed by at least one separate component part such as, e.g., a retaining ring, but also by a shoulder of the outer cylinder.

Optionally, it can be provided that an actuator piston which is connected to the adjustable spring plate is guided so as to be fixed with respect to relative rotation. This option is particularly useful when the adjustable spring plate has a supporting surface for the supporting spring which is inclined or radially offset with respect to a second spring plate.

It is possible for the maximum displacement path of the spring plate to be limited by a mechanical stop. This configuration facilitates control of the adjustable spring plate because a maximum displacement path is very easy to sense.

Various constructions are possible for implementation of the mechanical stop, e.g., a retaining ring fixed to the outer receptacle. An especially simple solution consists in that the outer cylinder of the vibration damper carries a cap which forms the mechanical stop. A cap of this kind can support, e.g., a pressure stop buffer of the vibration damper.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

FIGS. 1 and 2viewed together show a spring support1with an annular actuator3, the housing5of which is fastened to an outer cylinder7of a vibration damper constructed in any manner. The actuator3serves to axially adjust a spring plate9. The actuator3is supplied with pressure medium via a pressure medium supply system.11.

The pressure medium supply system11comprises at least one pump13, a pump drive15and a supply receptacle17. The housing5of the actuator3is directly connected to a housing19for the pressure medium supply system11. By direct connection between the two housings5;19is meant that there is a mechanically rigid connection. Sealing means or adapter components can be provided if necessary, but no gap-bridging hose connections.

The housing19of the pressure medium supply system11carries at least the pump13, the pump drive15and the supply receptacle17. The housing19need not completely enclose components13;15;17, but must provide at least connection surfaces to fulfill the supporting function.

As is further shown byFIGS. 1 and 2, the housing19of the pressure medium supply system11is arranged so as to be radially offset relative to the longitudinal axis21of the vibration damper. In this variant, a main axis23of the pressure medium supply system11extends in all planes parallel to the longitudinal axis of the outer cylinder7.

In addition, it can be seen from the sectional view inFIG. 2that the supply receptacle17is arranged above the pump13. Directly below the supply receptacle17, the pump13is located in a pump housing25which is in turn at least partially enclosed by housing19. The pump drive15adjoins below the pump13.

In this constructional variant, the annular housing5of the actuator and the housing19of the pressure medium supply system11, hereinafter referred to as total housing, are formed integrally. “Integrally” means that the two housings5;19in the end manufacturing state can no longer be separated without being destroyed.

The total housing5;19is supported on a radial step27of the outer cylinder7. In this case, the radial step27is formed by a widened diameter of the outer cylinder7.

The adjustable spring plate9is connected to a piston29which is supported in a pressure medium chamber31of the actuator3so as to be axially slidingly displaceable and so as to be sealed. In this regard, the outer cylinder7of the vibration damper forms an inner wall33of the pressure medium chamber31.

The pressure medium chamber31has a pressure medium connection35in the total housing5;19for the pump13. A pressure medium channel39between a pump chamber41and the connection channel35is formed on an outer lateral surface37of the pump housing25, seeFIG. 5. The pump housing25is fashioned in the region of the outer lateral surface with a dimensional accuracy such that it seals the pressure medium channel39from the environment jointly with an inner wall43of the housing19.

For axial displacement of the spring plate, pressure medium is conveyed from the supply receptacle17through the pressure medium channel39and the pressure medium connection35against the force of a spring, not shown, into the pressure medium chamber31via the pump drive15and the pump13. The displacement path of the spring plate9is limited by a mechanical stop45. To this end, this variant has a cap47which is pressed onto an end face49of the outer cylinder7or, alternatively, secured via a positive-engagement connection51. In this case, the positive-engagement connection51is held via a bead53between a sleeve portion55of the cap and at least one groove57which can also be formed circumferentially at the cylinder7.

In the construction according toFIGS. 1 and 2, the spring plate9is arranged at right angles to and concentric to the longitudinal axis21of the vibration damper or outer cylinder7. In contrast, the spring support1according toFIG. 3has an adjustable spring plate which is inclined relative to the longitudinal axis21. In case of an inclined spring plate9, it is necessary to ensure the defined inclination in circumferential direction through suitable measures.

To this end, the housing5of the actuator, which also forms the inner wall33of the pressure medium chamber31in this variant as is shown inFIG. 6, has a positive-engagement segment59which, along with a complementary positive-engagement segment61of the piston29at the spring plate9, ensures that the piston29and, therefore, the spring plate9is guided so as to be fixed with respect to relative rotation.

Another difference compared to the variant according toFIGS. 1 and 2consists in that the mechanical stop45for limiting the displacement path of the spring plate9is formed by a retaining ring which engages in a circumferential groove63. This variant is suitable particularly when the maximum displacement position of the spring plate9is at a large distance from the end face49of the outer cylinder7.

FIG. 4is distinguished fromFIG. 3in that the radial step27for supporting the total housing5;19is likewise formed by a retaining ring65in a groove67.

FIGS. 7 to 9show an embodiment form in which the housing5of the actuator and the housing19for the pressure medium system11are component parts which can be produced separately and which are screwed together to form the total housing. To this end, housing5has connection surfaces69for fastening surfaces71of the housing19of pressure medium supply system11.

FIGS. 7 and 9show an orientation of housings5;19according toFIGS. 1 to 4. The difference between these two constructions is that a positive-engagement pressure relief joint73which is independent from the screw connection is provided inFIG. 9. A dovetail guide is shown by way of example. The two housings5;19can be oriented axially relative to one another via the dovetail guide so that the screw connection can be closed more easily, but radial pull-off forces between the housings5;19are absorbed by the pressure relief joint73. A compressive load proceeds from the pressure in the pressure medium chamber31of the actuator5.

FIG. 8is intended to show that the two housings5;19can also be oriented skew to one another. For this purpose, the connection surfaces69and the fastening surfaces71are correspondingly located at the respective housings5;19. As is shown inFIG. 8, a housing19according toFIG. 7can be used and only connection surfaces69can be oriented correspondingly at the actuator housing5.