Pump arrangement, particularly for an adjustable suspension system

Abstract

The invention relates to a pump arrangement comprising a pump with a pump drive and an annular reservoir which at least partly encloses the pump and pump drive, said reservoir comprising, inside a rigid reservoir housing, a hydraulic pressure medium volume and a gas volume which is spatially separated therefrom, the gas volume being contained in a flexible sleeve body, closed off with respect to the pressure medium volume, inside the reservoir housing.

Description

[0001] The invention relates to a pump arrangement, in particular for an adjustable chassis system, according to the preamble of claim 1.

[0002] DE 10 2015 208 785 A1 describes an adjustable chassis system with a pump arrangement. The design according to Fig. 4 shows a pump arrangement with an annular reservoir that encloses at least a longitudinal section of the pump arrangement. The specific structural design of the pump arrangement, in particular of the reservoir, is not the subject of DE 10 2015 208 785 A1.

[0003] DE 10 2018 129 539 A1 discloses a pump assembly with a ring accumulator as part of an actuation module for a drive train. Here, too, the accumulator encloses at least part of the pump assembly. The ring accumulator comprises an axially movable annular piston that separates a gas chamber from a pressure medium chamber.

[0004] The object of the present invention is to further develop the concept of the annular reservoir in a pump arrangement.

[0005] The task is solved by enclosing the gas volume in a flexible casing within the storage housing that is sealed off from the pressure medium volume.

[0006] The use of the flexible housing has led to a significant improvement in noise emissions. The gas column within the housing reduces the noise transmission from the pump and pump drive to the surrounding environment.

[0007] To reduce the mechanical stress on the casing, the casing has an arched shape adapted to the cross-section of the storage tank. The casing rests at least partially on a wall of the storage housing.

[0008] Optionally, multiple enveloping bodies can be arranged in the reservoir. The number of enveloping bodies can be used to dimension the pressure medium volume or the pressure characteristic while maintaining a constant reservoir size.

[0009] According to an advantageous subclaim, the casing has a filling connection that penetrates a wall of the storage housing. This allows the casing to be filled during assembly, if necessary.

[0010] Furthermore, it can be provided that the filling connection of the at least one enveloping body and a filling connection for the pressure medium are arranged in a common surface area of ​​the accumulator housing. This feature is particularly advantageous in tight installation spaces, where the two connections can be arranged directly next to each other.

[0011] If necessary, the filling connection can also be equipped with a fuse, for example to ensure controlled gas discharge in the event of a fire so that the storage tank is not overloaded with pressure.

[0012] Optionally, at least two accumulators can be arranged axially stacked and have facing contact surfaces for a hydraulic connection between the at least two accumulators. In this case, a standard accumulator can be used and then multiplied to a desired storage volume via the stacking arrangement.

[0013] Alternatively, at least two storage units can be arranged concentrically to one another, wherein an outer surface of a storage housing of an inner storage unit forms an inner surface of an outer storage housing.

[0014] The invention will be explained in more detail with reference to the following description of the figures.

[0015] It shows: Fig. 1 Schematic diagram of the application of the pump arrangement Fig. 2 Sectional view through the pump arrangement Fig. 3 Pump arrangement with axially stacked storage Fig. 4 Pump arrangement with concentric storage arrangement Fig. 5 Storage with several casing bodies

[0016] The Figure 1 shows a schematic diagram of the combination of a pump assembly 1 with a vibration damper 3. The pump assembly 1 comprises a pump 5 with a pump drive 7. The application of the invention is particularly suitable and expedient for a pump 5 with a non-uniform delivery volume, e.g., a gear pump. Especially with pumps 5 with a non-uniform delivery volume, noise emissions occur, which are, for example, carried into the passenger compartment.

[0017] The pump assembly 1 has an annular accumulator 9 that at least partially encloses the pump 5 and the pump drive 7. The pump 5 preferably has two delivery directions. Valves and other components of the hydraulic system have been omitted. The accumulator 9 has a rigid accumulator housing 11 in which a hydraulic pressure medium volume 13 and a spatially separated gas volume 15 are chambered. The gas volume 15 is chambered in a flexible casing 17 within the accumulator housing 11, which is sealed off from the pressure medium volume 13. The casing 17 floats within the pressure medium volume 13. Unlike an enclosed liquid, the sound transmission of the gas within the casing 17 is significantly lower. The casing 17 thus acts as a sound insulator for the pump assembly 1.

[0018] The enveloping body 17 has, as in the Fig. 5As shown, it has an arcuate shape adapted to the cross-section of the accumulator 9 and is supported at least partially on a wall of the accumulator housing 11. This radial support of the enveloping body 17 ensures a comparatively low hydraulic load on the enveloping body 17. It is also possible for several enveloping bodies 17 to be arranged in the accumulator, e.g., standardized accumulators that are inserted into the accumulator housing 11 as required.

[0019] The vibration damper 3 after Fig. 1is based on a cylinder 19 in which a piston rod 21, together with a valve-equipped piston 23, executes an axial displacement movement. The vibration damper 3 also has a reservoir 25 as a compensation chamber for the pressure medium displaced by the piston rod 21. The compensation chamber 25 is radially delimited by the cylinder 19 and an outer container tube 27. A piston rod guide 29 and a base 31 close the axial ends of the compensation chamber 25, which also contains a gas volume 15 and a pressure medium volume 13. An axially movable annular separating piston ensures spatial separation of gas and pressure medium. In principle, the structural design of the vibration damper 3 is subordinate to the application of the invention.

[0020] There is a hydraulic connecting line 35 between the pump arrangement 1 and the vibration damper 3, so that a more or less large extension force can be generated on the piston rod by means of the pump arrangement 1 via a pressure medium supply or discharge into or from the vibration damper 3.

[0021] Furthermore, the Fig. 2 that the enveloping body 17 has a filling connection 37 that penetrates a wall of the accumulator housing 11. Preferably, the filling connection 37 of the at least one enveloping body 17 and a filling connection 39 for the pressure medium are arranged in a common surface area of ​​the accumulator housing 11. A preferred location for the filling connections is axial cover surfaces 41, since these are at least partially designed as flat surfaces and can therefore be easily hydraulically sealed.

[0022] The filling connection 37 for the filling body 17 has a closing body 43, preferably made of plastic, which, due to its temperature properties, can also be designed as a fuse. At a sufficiently high temperature, the closing body 43 melts, the gas volume 15 can escape, and the accumulator 9 then loses its compressive preload. This eliminates a pressure cushion that, for example, in the event of an accident and a resulting damaged accumulator 9, would force the pressure medium out of the accumulator 9 and possibly spray it. The pressure medium in the liquid phase burns off virtually safely. The same medium as an oil cloud would be considerably more flammable.

[0023] With the Fig. 3In a pump arrangement 1, it is intended to demonstrate that the combination of several accumulators 9A; 9B is significantly simpler due to the use of the enveloping body 17 than with an accumulator with an axially movable separating piston. It is then possible for at least two accumulators 9A; 9B to be arranged axially stacked and for mutually facing contact surfaces 45; 47 to have an axial hydraulic connection port 49 between the at least two accumulators 9A; 9B. Both accumulators 9A; 9B can be filled via the filling ports 37; 39. In a conventional accumulator, an external connecting line would have to be used to bridge the gas space.

[0024] The Figure 4shows an alternative variant of the pump arrangement 1, in which at least two accumulators 9A; 9B are arranged concentrically to one another. An outer jacket surface 51 of an accumulator housing 53 of the inner accumulator 9A and an inner jacket surface 55 of an outer accumulator housing 57 then form the second accumulator 9B. Simple tubular bodies with different diameters can then be used to form the dividing walls between the individual accumulators 9A; 9B. This design would not be possible with an accumulator with a floating separating piston, since a cylinder is calibrated to either an inner diameter or an outer diameter and only the calibrated diameter is suitable as a running path for a separating piston. A radial connecting connection 49, for example, can exist between the two accumulators 9A; 9B. Reference symbol

[0025] 1Pump arrangement 3Vibration damper 5Pumps 7Pump drive 9Accumulator 9AAccumulator 9BCumulator 11Accumulator housing 13Pressure medium volume 15Gas volume 17Envelope 19Cylinder 21Piston rod 23Piston 25Accumulator 27Vessel tube 29Piston rod guide 31Bottom 33Separating piston 35Connecting line 37Filling connection 39Filling connection 41Cover surface 43Closing body 45Contact surface 47Contact surface 49Connecting connection 51Shell surface 53Accumulator housing 55Shell surface 57Accumulator housing

Claims

1. Pump arrangement (1), comprising a pump (5) with a pump drive (7) and with an annular store (9; 9A; 9B) which at least partially envelops the pump (5) and the pump drive (7), wherein the store (9; 9A; 9B) comprises within a rigid store housing (11) a hydraulic pressure-medium volume (13) and a gas volume (15) spatially separated therefrom, characterized in that the gas volume (15) is partitioned off within the store housing (11) in a flexible enveloping body (17) which is closed off with respect to the pressure-medium volume (13).

2. Pump arrangement according to Claim 1, characterized in that the enveloping body (17) has an arcuate shape adapted to the cross section of the store housing (11) and is supported at least partially against a wall of the store housing (11).

3. Pump arrangement according to Claim 1 or 2, characterized in that multiple enveloping bodies (17) are arranged in the store (9; 9A; 9B).

4. Pump arrangement according to at least one of Claims 1-3, characterized in that the enveloping body (17) has a filling connection (39) which passes through a wall of the store housing (11).

5. Pump arrangement according to Claim 4, characterized in that the filling connection (37) of the at least one enveloping body (17) and a filling connection (39) for the pressure medium (13) are arranged in a common surface region (41) of the store housing (11).

6. Pump arrangement according to Claim 4, characterized in that the filling connection (37) has a fuse (43).

7. Pump arrangement according to at least one of Claims 1 - 6, characterized in that at least two stores (9A; 9B) are arranged in an axially stacked manner, and mutually facing contact surfaces (45; 47) have a hydraulic connecting connection (49) between the at least two stores (9A; 9B).

8. Pump arrangement according to at least one of Claims 1 - 7, characterized in that at least two stores (9A; 9B) are arranged concentrically with respect to one another, wherein an outer lateral surface (51) of a store housing (53) of an inner store (9A) forms an inner lateral surface of an outer store housing (9B).

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