US20020056275A1

US20020056275A1 - Hydraulic accumulator

Info

Publication number: US20020056275A1
Application number: US09/935,762
Authority: US
Inventors: Norbert Weber
Original assignee: Hydac Technology GmbH
Current assignee: Hydac Technology GmbH
Priority date: 2000-11-16
Filing date: 2001-08-24
Publication date: 2002-05-16
Also published as: EP1334280A2; US6866066B2; ES2246352T3; EP1334280B1; US20040028542A1; WO2002040871A3; WO2002040871A2; ATE301777T1; DE50107069D1; JP2004514096A; DE10057746A1

Abstract

A hydraulic accumulator, particularly a floating piston accumulator, has a housing containing at least one gas chamber and one fluid chamber. The chambers are separated from one another by a barrier element. One of the chambers can be filled with a pressure medium or can be at least partially emptied through a controlling valve assembly having at least one control valve. The controlling valve assembly is an integral component part of the housing, is attached at an end to the housing and is configured as a solid control block. The control block includes the control valve. A costly network of lines between the hydraulic accumulator and the controlling valve assembly is avoided and sealing or leakage problems customary in networks of lines can be totally avoided.

Description

FIELD OF THE INVENTION

The present invention relates to a hydraulic reservoir or accumulator, particularly a piston or floating piston accumulator, having a housing with at least one gas chamber and one fluid chamber arranged therein. The chambers are separated from one another by a barrier element. At least one chamber can be filled with a pressure medium through a controlling valve assembly including at least one control valve or can be at least partially emptied using that control valve.

BACKGROUND OF THE INVENTION

One of the main purposes of hydraulic accumulators is to retain certain volumes of fluid making up a hydraulic system under pressure, and, when the fluid is called back, to feed this fluid back into the system under pressure. Hence traditional floating piston accumulators, dissolved gas-drive bubble accumulators, or diaphragm accumulators are considered as hydraulic accumulators. Weight-biased and spring-biased accumulators can be included in this group. A plurality of objectives can be realized with such hydraulic accumulators, such as energy storage, impact absorption, shock absorption, vibration absorption, pulsation absorption, energy recovery, flow volume compensation and so forth.

Controlling valve assemblies can be used for the operation and control of the hydraulic accumulator. Such valve units are traditionally provided with switching or multi-way valves for the generation of the fluid current from and to the hydraulic accumulator. The hydraulic accumulator is hence normally attached to a tubing or conduit system having fluid-conveying lines, which produce the fluid-conveying connection or fluid communication between the accumulator and the controlling valve assembly.

Drawbacks of such a known accumulator, which can obviously be attained in a number of different embodiments presently on the market, reside in the form of sealing problems arising as a result of the increased number of connections between hydraulic accumulator conduit systems and controlling valve assemblies, and can also be seen in the additional costs for the network of conduits serving as fluid lines. Particularly with construction relationships and systems of narrow dimensions, problems can arise involving the accommodation of the great plurality of these components and connecting them with one another so that they will be in fluid communication. Since various manufacturers are responsible for manufacturing hydraulic accumulators, including the conduit systems and/or the valves of the controlling valve assembly, difficulties of adaptation and fitting of the parts arise particularly at the site of the construction.

SUMMARY OF THE INVENTION

Objects of the present invention are to overcome these drawbacks of conventional accumulators.

The foregoing objects are basically obtained by a hydraulic accumulator, comprising a housing having at least one gas chamber and at least one fluid chamber therein, a barrier element in the housing separating the gas and fluid chambers, and a controlling valve assembly attached at one end of said housing as a integral component part thereof. The controlling valve assembly includes a solid control block and a first control valve located in the control block. The first control valve is in fluid communication with and controls the flow of a pressure medium into and out of one of the chambers.

Since the controlling valve assembly is an integral part of the accumulator housing, attached at the end to the housing and configured as a solid control block including essentially the relevant control valve, the conventional costly network of lines between the hydraulic accumulator and the controlling valve assembly is avoided. The sealing or leakage problems, as customary in networks of lines, quite certainly cannot occur at all. Manufacture and installation costs for the hydraulic accumulator are considerably reduced by avoiding the use of fluid lines. Tying in of the controlling valve assembly as an integral component part of the hydraulic accumulator allows for very tight construction dimensions. Even with limited availability of construction dimensions in vehicles or in buildings, such as within mechanical installations, suitable installations can still be undertaken. Since the controlling valve assembly is aligned directly as the control block on the hydraulic accumulator, the controlling valve assembly can also work directly on the accumulator, so that the accumulator function has extraordinarily short reaction times and fluid volumes can be carried in and out of the accumulator chambers in the shortest time possible. The solution according to the present invention reduces or entirely prevents loss of pressure between valve and hydraulic accumulator (the user).

In one particularly preferred embodiment of the hydraulic accumulator of the present invention, the control block engages with its appendix part in flush contact with the interior periphery inside the accumulator housing. The accumulator housing with its one open end engages on a setoff section of the control block, at which the appendix part begins. Secure sealing of the connection between accumulator housing and control block appendix part can be attained as a result of this configuration. Furthermore, through the setoff section, precise contact of the accumulator housing with the control block is possible and the accumulator housing is guided precisely along the appendix part of the control block. Undesirable separation of accumulator housing from controlling valve assembly is thus absolutely avoided.

In the case of another preferred embodiment of the hydraulic accumulator of the present invention, the control block with its appendix part limits the fluid chamber. The control block then has at least one fluid passage with its one open end opening into the fluid chamber and with its other open end attached to the control valve. Since the control block fits directly into the fluid chamber, the open multi-way passages for the pressure medium are of limited dimensions, providing rapid reaction times for the hydraulic accumulator.

With one particularly preferred embodiment of the hydraulic accumulator of the present invention, at least one further control valve, in addition to the first control valve, is present in the control block. This additional control valve can be connected in fluid communication with the gas chamber, and can control the inlet and discharge of working gas in the gas chamber. In the case of another similar construction, the additional control valve can be connected in fluid communication with and to act on a separate structural group involving a hydraulic circuit to undertake control of the fluid displacement.

Other objects, advantages and salient features of the present invention will become apparent from the following detailed description, which, taken in conjunction with the annexed drawing, discloses a preferred embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWING

Referring to the drawing which forms a part of this disclosure: [0012]
FIG. 1 is a front elevational view, partially in section, of a hydraulic accumulator according to an embodiment of the present invention.[0013]

DETAILED DESCRIPTION OF THE INVENTION

The hydraulic accumulator shown in FIG. 1 is configured as a floating piston accumulator or reservoir. This unit includes an [0014] accumulator housing 10 with a gas chamber 12 and a fluid chamber 14 arranged therein. Gas chamber 12 is separated from the fluid chamber 14 by a barrier element 16 in the form of a portion of a piston. The piston is guided for longitudinal sliding movement along the interior periphery of accumulator housing 10, so that the ratio of the dimensions of gas chamber 12 to fluid chamber 14 is variable. In order to be able to store a greater volume of gas to be used as work gas in gas chamber 12, barrier element 16 is configured as a hollow member. The interior of the barrier element incorporates a suitable cutout 18 in its design.
When viewing [0015] gas chamber 12 as seen in the drawing, the top is closed by a cover part 20. Chamber 12 is accessible through a middle bore 22, through which a working gas, for instance nitrogen, can be fed into gas chamber 12. Middle bore 22 is then sealed off gas-tight by a shutoff valve or the like (not shown), whereby from time to time the volume of gas in gas chamber 12 can be tested and can be refilled through such shutoff valve.
The controlling valve assembly, indicated in its entirety as [0016] 26, is enclosed in a control block 24 at the opposite end of reservoir housing 10 from cover part 20. Controlling valve assembly 26 houses a first control valve 28 and a second control valve 30. The controlling valve assembly 26 is consequently an integral component part of reservoir housing 10. For this purpose, control block 24 is provided with a projection 32 engaged in flush contact with the interior periphery inside reservoir housing 10. Accumulator housing 10 engages with its one open end 34 on a setoff section 36 of control block 24, at which the projection or appendix part 32 begins. The other exterior diameter of control block 24, at appendix part 32 engaged in reservoir housing 10, is consequently reduced in diameter according to the degree of pulling back over setoff section 36.
[0017] Control block 24 limits the bottom of fluid chamber 14 with the top end of appendix part 32 extending upwardly from below as seen in the drawing. Accumulator housing 10, chambers 12 and 14, cover part 20, piston part 16 as well as appendix part 32 are configured essentially as cylindrical structural parts and are aligned along the common longitudinal axis 38 of the hydraulic accumulator. Control block 24 furthermore has a fluid passage 40 arranged off-center to or laterally offset from longitudinal axis 38. One open end of passage 40 opens into fluid chamber 14. The other open end of passage 40 is connected to the first control valve 28. Transverse to fluid passage 40, a transverse connection 42 extends into control block 24, to which could potentially be attached a fluid feed line, for example, as a component part of a hydraulic circuit. Between transverse connection 42 and fluid passage 40, first control valve 28 is mounted, whereby the fluid-conveying connection between transverse connection 42 and fluid passage 40 is opened in one switch setting and is blocked off in the other switch setting.
Preferably, the [0018] first control valve 28 is configured as a 2/2-way valve. However, other valves could be used at this point in the arrangement, such as multi-way-slide-valves, valves with damping fixtures or the like, dependent upon the intended use.
In parallel construction and aligned in the same direction as [0019] first control valve 28, another or second control valve 30 is arranged and is also configured in the present case as a 2/2-way valve. Second control valve 30 has two side connections 44 and 46, extending from the valve in manners similar to the transverse connection 42 in radial alignment on the side extending out from control block 24. The two side connections 44 and 46 are in turn separated from one another on the switch parts of second control valve 30. With second control valve 30 connected through, the side attachments 44 and 46 are connected with one another fluid-carrying or in fluid communication, and then are separated from one another when the valve is switched into a blocking setting. With such an arrangement of second control valve 30, for example, according to an embodiment which is not described herein in greater detail, the inlet and discharge of the work gas in and out of gas chamber 12 can be controlled when connections 44 and 46 are coupled in fluid communication through connection 60 to cover part 20 with gas chamber 12. In another embodiment not described in greater detail, second control valve 30 can control a different structural group 62 in the hydraulic circuit, for example in the form of a hydraulic working cylinder or the like, through connection 64.
In the present embodiment, [0020] control valves 28 and 30 are configured as magnet valves 48, which can be controlled electrically through connections 50. Since such magnet valves 48 are the present state of the art or are conventional they will not be discussed in greater detail.
The hydraulic accumulator of the present invention realizes a complete solution of the problems addressed by the invention and allows a compact structural embodiment. In the embodiment shown in the drawing, first and [0021] second control valves 28 and 30 are essentially axially parallel to longitudinal axis 38 of the hydraulic accumulator arranged above the valves in control block 24. However, other structural layouts can be used, particularly a radial layout transverse to longitudinal axis 38. Because of the flush connection of reservoir housing 10 to control block 24, leakage is avoided and a costly system of tubing can also be avoided. Since control block 24 engages directly with its appendix part 32 in fluid chamber 14 of accumulator housing 10, particularly the first control valve 28 is arranged directly in the vicinity of fluid chamber 14, and is separated therefrom only by the fluid passage 40 which is of short structural length, so that the hydraulic accumulator can be actuated with very short control reaction delays.
While one embodiment has been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention as defined in the appended claims.[0022]

Claims

What is claimed is:

1. A hydraulic accumulator, comprising:

a housing having at least one gas chamber and at least one fluid chamber therein;

a barrier element in said housing separating said gas and fluid chambers; and

a controlling valve assembly attached at one end of said housing as an integral component part thereof, said controlling valve assembly including a solid control block and a first control valve located in said control block, said first control valve being in fluid communication with and controlling the flow of a pressure medium into and out of one of said chambers.

2. A hydraulic accumulator according to claim 1 wherein

said barrier element is a floating piston.

3. A hydraulic accumulator according to claim 1 wherein

said control block comprises an appendix part engaging an inside surface of said housing and an offset section at a beginning of said appendix part engaging an open end of said housing.

4. A hydraulic accumulator according to claim 3 wherein

said appendix part defines one end of said fluid chamber; and

said control block comprises at least one fluid passage with one open end thereof opening with another open end thereof coupled to said control valve.

5. A hydraulic accumulator according to claim 4 wherein

said controlling valve assembly comprises a second control valve in said control block adjacent said first control valve.

6. A hydraulic accumulator according to claim 5 wherein

said second control valve is in fluid communication with said gas chamber for controlling flow of working gas into and out of said gas chamber to control pressure therein.

7. A hydraulic accumulator according to claim 6 wherein

said gas chamber comprises an additional fluid chamber and controls a different structural group in a hydraulic circuit.

8. A hydraulic accumulator according to claim 5 wherein

each of said control valves comprise a 2/2-way valve.

9. A hydraulic accumulator according to claim 1 wherein

said first control valve comprises a 2/2-way valve.

10. A hydraulic accumulator according to claim 9 wherein

said 2/2-way valve is an electrically controlled magnet valve.

11. A hydraulic accumulator according to claim 8 wherein

said 2/2-way valves are electrically controlled magnet valves.

12. A hydraulic accumulator according to claim 1 wherein

said housing and said control block are essentially cylindrical.