EP1808605B1 - Method for manufacturing piston-type accumulators - Google Patents

Abstract

The production process produces a piston-type accumulator with a housing (10) and a separate piston. The endfaces of the housing are each sealed by a cover part (20), fixed on one side (40) via the free longitudinal edge (32) of the housing, which is displaced towards the cover part to fit it in a positive secure connection.

Description

The invention relates to a method for producing piston accumulators according to the feature configuration of the preamble of claim 1.

Piston accumulator as exemplified in the DE 2 238 211 A are shown in the broadest sense belong to the so-called hydraulic accumulators, which serve, inter alia, to hold certain volumes of pressurized fluid (hydraulic medium) of a hydraulic system and return them to the system if necessary. Since the hydraulic medium is under pressure, the hydraulic accumulators are treated like pressure vessels and must be designed for the maximum operating pressure, taking into account the acceptance standards of various installation countries. In most hydro plants today hydropneumatic (gas-loaded) memory are used with separating element, wherein the piston accumulators as a separating element serves a piston which separates a liquid space as a working space of a gas space as another working space within the storage housing of the piston accumulator. Nitrogen is regularly used as working gas and the gas-tight piston largely allows a decoupling of gas space to liquid space.

The liquid part communicates with the hydraulic circuit, so that when the pressure rises, the piston accumulator receives liquid and the gas is compressed. With decreasing pressure, the compressed gas expands, displacing the stored pressure fluid back into the hydraulic circuit. One advantage of piston accumulators is that they can "work" in any position, but a vertical arrangement with the gas side upwards is preferable in order to avoid settling of dirt particles from the liquid on the piston seals.

The essential components of a piston accumulator are therefore as an accumulator housing an outer cylinder tube, the piston as a separating element with its sealing system and the front-side cap, which at the same time include a liquid and gas connection as cover parts. The memory housing regularly two functions, namely once to stockpile the internal pressure and to ensure the other hand, the leadership of the piston within the storage enclosure. In a known solution according to the JP 03 092679 A (SHOWA MFG Co. Ltd.) April 17, 1991 (1991-04-17), the front side of the interior of the storage enclosure relative to the environment final lid parts are provided on the outer peripheral side with an external thread in a corresponding internal thread along the free longitudinal edge of the storage enclosure via a specifiable distance can be screwed. The preparation of the pertinent threaded connection is time consuming, which increases the cost of manufacturing the piston accumulator accordingly. Furthermore, safety measures must be taken to secure the inserted cover part in its position in the storage housing.

By the DE 42 05 199 A (SHOWA SEISAKUSHO GYODA KK) September 10, 1992 (1992-09-10) and Patent Abstracts of Japan Vol. 1999, No. 13, November 30, 1999 (1999-11-30) &; JP 11 230102 A (KAYABA IND Co. Ltd.), August 27, 1999 (1999-08-27) generic methods for producing piston accumulators are known, with a storage housing and a storage housing longitudinally movable separating piston, which separates two working spaces within the storage housing from each other, the end is closed by a respective cover part, optionally in one-piece housing design, wherein on one side of at least one cover part this is fixed over the free longitudinal edge of the storage housing, which experiences a Zustellbewegung on the cover part for this purpose, said cover part to the outside of the storage enclosure closes and is used with its one side opposite side against a stop in the interior of the storage enclosure in this and / or that the respective cover part is held by the clamping force of the delivered free longitudinal edge in its end position. By the DE 42 05 199 A is also known to leave the free longitudinal edge opposite the other storage enclosure in the wall thickness equal or even amplify accordingly, said transition point between the same wall thicknesses in the free end region of the storage enclosure forms the stop for a paragraph-like projection on the outer periphery of the cover part within the storage enclosure , which so far oriented towards the environment outwardly protrudes.
The known solutions are complicated to manufacture and involve at the location of the lid exposed to the outside the risk of damage to the lid part.

Based on this known state of the art, the invention has the object to further improve the known production method for piston accumulator to the effect that with little manufacturing effort a functionally reliable and secure connection of a cover part in the storage enclosure a piston accumulator is guaranteed and that damage to the cover part can be avoided. This object is achieved by a method having the features of claim 1 in its entirety.

Characterized in that according to the characterizing part of claim 1, the longitudinal edge is reduced compared to the other memory housing in the wall thickness, that the transition point between these different wall thickness forms the stop for the cover part within the storage enclosure, and that the free longitudinal edge along its free end flush or is guided with a supernatant on the overhead second side of the lid part, a kind of clamping seat is achieved at the respectively associated free end of the storage enclosure for the cover part, wherein the Dekkelteil is clamped at least over the free longitudinal edge of the storage housing after its feed movement to the lid part, said it is sufficient if a part of the free longitudinal edge of the pertinent press fit.

The stop provided on the inside of the storage housing makes it possible for the delivery movement of the free longitudinal edge of the storage housing to fix the cover part against this stop. Additionally or alternatively, however, it is also possible to simply insert the cover part at the free end of the storage housing and then trigger the Zustellbewegung for the free longitudinal edge of the storage enclosure, which in dergestalt with the known solutions, for example, after DE 42 05 199 C2 not possible. The Zustellbewegung can take place against the top cover, if the cover part is held in a pertinent position; but it would also be conceivable to carry out a free feed movement for the longitudinal edge, and then then in the ready state, the cover part on the guided in the storage chamber piston against the free To proceed along the longitudinal edge, which then makes such a clamp here. Preferably, it is provided that the lid part is inserted with its one lower side against the stop inside the storage housing or that the stop for the lid part is provided with a slope against which the lid part is based in a stepped paragraph.

Due to the opposite to the lid part projecting longitudinal edge a secure position of the lid part is achieved in the storage housing and the cover part is protected from damaging force application.

Preferably, it is further provided that for the feed movement of the longitudinal edge of the storage housing, a forming tool is provided which provided with Zustellschrägen the longitudinal edge of the storage housing on the cover part such that this is determined in the manner of said clamping fit in the storage enclosure.

In a particularly advantageous embodiment of the method according to the invention take in a common feed movement to the storage housing two forming tools on opposite sides before the fixing process for the respective end cover part by acting on the respective free longitudinal edge of the storage enclosure. It has proven to be very advantageous for the generation of high locking forces to deliver both free ends of the cylindrical storage enclosure alike, said acting at one end of the storage enclosure forming tool can safely support the forces from the other side during the forming process with the other forming tool be introduced into the storage enclosure.

Further advantageous embodiments are the subject of the other dependent claims.

Fig.1

einen Längsschnitt durch einen Kolbenspeicher nach dem Stand der Technik;

Fig.2

im Längsschnitt den oberen Teil einer ersten Ausführungsform eines Kolbenspeichergehäuses mit darüberliegendem Umformwerkzeug;

Fig.3 und 4

im Längsschnitt das Aufsetzen eines Montagewerkzeuges auf das freie Ende des Speichergehäuses zwecks Festlegen eines Deckelteils;

Fig.5 und 6

im Längsschnitt den oberen Bereich des Speichergehäuses in zwei verschiedenen Varianten mit innen liegenden Einführschrägen zum Einführen des Deckelteils;

Fig.7

ebenfalls im Längsschnitt den oberen Teil einer zweiten Ausführungsform eines Kolbenspeichergehäuses mit geändertem Deckelteil.

In the following the method according to the invention will be explained in more detail with reference to the drawing. This show in principle and not to scale representation of the

Fig.1

a longitudinal section through a piston accumulator according to the prior art;

Fig.2

in longitudinal section the upper part of a first embodiment of a piston accumulator housing with overlying forming tool;

3 and 4

in longitudinal section, the placement of an assembly tool on the free end of the storage enclosure for the purpose of setting a cover part;

Fig.5 and 6

in longitudinal section the upper region of the storage housing in two different variants with internal insertion bevels for insertion of the cover part;

Figure 7

also in longitudinal section the upper part of a second embodiment of a piston accumulator housing with a modified cover part.

The in Fig.1 shown, counting to the prior art piston accumulator has as a storage housing 10, an outer cylinder tube in which as Separating a piston 12 with its outer peripheral sealing system 14 is guided longitudinally movable. The piston 12 separates within the storage housing 10, two working spaces 16,18 from each other, wherein the one working chamber 16 receiving a working gas, in particular in the form of nitrogen, and the other second working space 18 forms the so-called. Liquid space for the piston accumulator. Depending on the operating situation of the memory, the displacement position of the piston 12 and consequently the volume proportions of gas and fluid in the work spaces 16 and 18 vary. At the front end of the storage housing 10, a cover part 20, 22 is arranged with a gas connection 24 for replenishing the nitrogen working gas and with a fluid port 26 for connecting the piston accumulator to a not-shown hydro overall system.

The two cover parts 20,22 are each provided with an external thread 28 which is engageable with an internal thread 30 which is arranged to extend along the free longitudinal edge 32 and opens outwards into the open. On the outer circumference, the respective cover part 20, 22 is provided with a seal 34 for sealing the interior of the storage housing 10 from the surroundings. The attachment of the threaded sections 28,30 is associated with a certain manufacturing effort, which can be costly and expensive to manufacture the known piston accumulator. In addition, an anti-twist device for the respective cover part 20, 22 is necessary in order to ensure its positional fixation within the storage housing 10. A possible anti-rotation for the respective Dekkelteil 20,22 may consist in that along the threads 28,30 provides a conventional adhesive assurance or the cover part is held with a conventional retaining hole (with and without thread) in position.

Based on this known solution, the method according to the invention will now be described in more detail with reference to Fig.2ff, which allows a functionally reliable connection of the cover part with the associated memory housing 10 in a cost effective manner. For the sake of simplicity, it has accordingly been incorporated in the Fig.2 only the upper end of the storage case 10 shown together with the upper cover part 20. Unless the following components are addressed as in the known embodiment according to the Fig.1 , the corresponding components with the same reference numerals as in Fig.1 referred to.

The method according to the invention is characterized, inter alia, by the fact that a cover part, here the cover part 20, is inserted with its one lower side 36 against a stop 38 in the form of an annular surface in the interior of the storage housing 10, wherein on the opposite side 40 of the cover part 20 this is determined over the free longitudinal edge 32 of the storage enclosure 10, for which purpose the longitudinal edge 32 undergoes a feed movement to the cover part 20, which will be explained in more detail below.

For the delivery of the longitudinal edge 32 of the storage enclosure 10 is a forming tool 42 which is provided with at least one feed bevel 44, which sets the longitudinal edge 32 on the lid member 20 that this in the manner of a clamping fit in the storage housing 10 between the stop 38 and the Longitudinal edge 32 is fixed. To create the pertinent clamping seat, the upper side 40 of the cover part 20 is provided with a contact surface 46, which is arranged conically to the longitudinal axis 48 of the storage housing 10 extending. The inclination of the pertinent contact surface 46 corresponds to the inclination of the feed bevel 44 of the forming tool 42; but there are also other obvious tendencies or

Sloping conceivable. As the presentation after the Fig.2 shows, the feed direction for the forming tool 42, the longitudinal axis 48 of the storage housing 10 and the entire piston accumulator.

The better representation because of was in the Fig.2 omitted the separator in the form of the piston 12 as well as in Fig.1 illustrated gas port 24, which is also an integral part of the upper lid part 20 here. Before the clamping connection is made via the forming tool 42, the upper free end of the storage housing with its upper longitudinal edge 32 has a contour according to one of the representations of the 3 to 6 , In this case, the longitudinal edge 32 is reduced in relation to the other storage housing 10 in the wall thickness, wherein the transition point between the various wall thicknesses forms the stop 38 for the cover part 20. Furthermore, the longitudinal edge 32 is preferably provided on its side facing the cover part 20 and outwardly oriented with a conical insertion bevel 50. The pertinent insertion bevel 50 facilitates the insertion of the cover part 20 in the free upper end of the storage housing 10, which will be explained in more detail below.

Furthermore, the free longitudinal edge 32, which in particular the representation according to the 4 and 5 shows, on the outer circumference side and to the free end of the storage enclosure 10 out towards be provided with a sliding bevel 52, which makes it easier for the longitudinal edge 32, from its cylindrical shape according to the representations of the 3 to 6 to pass into a notified inclined position, wherein the sliding bevel 52 then slides along the feed slope 44 of the forming tool 42, provided that it is increasingly placed in the feed direction on the storage housing 10. If the feed movement is completed with the forming tool 42, the longitudinal edge 32 is on the cover part 20 along its contact surface 46 in the manner of a Festgeschräge formed inclined and holds the lid member 20 against the stop 38 in the interior of the storage enclosure 10 fixed.

In order not to jeopardize the secure position of the cover part 20 in the storage housing 10 and also to protect the cover part 20 from damaging force discharges, as shown in the illustration Fig.2 shows, the free longitudinal edge 32 along its free end with a supernatant on the overhead second side 40 of the cover part 20 is guided. After determining the pertinent clamp connection, the forming tool 42 is moved away from the storage housing 10 again and then takes, for example, his in the Fig.2 shown upper position. Preferably, the forming process for the respective longitudinal edge 32 of the storage housing 10 is cold; but it is also a hot forming conceivable with appropriate heating of the storage housing material and preferably the forming tool 42 itself. As a material for the storage housing 10 with its longitudinal edge 32 is a conventional, good moldable steel material used. In order to optimally initiate the clamping forces in the cover part 20 and also to ensure a good support in the storage housing 10 at the edge for the cover part 20, it is provided that the height of the cover part 20 is adapted in each case to the predetermined by the operation of the storage conditions. In the case shown, the cover part 20 is at least twice as large as the length of the longitudinal edge 32 between its free end and a deflection point 54, from which the longitudinal edge 32 is placed on the lid top.

In a particularly preferred embodiment (not shown) of the method according to the invention is in a common feed movement two forming tools 42 on opposite sides of the storage housing 10 of the fixing process for the respective end-side cover part 20,22 made simultaneously and together with substantially the same forming forces by acting on the respective free longitudinal edge 32 of the storage enclosure 10. It has been found that in the pertinent forming solution, the respective opposite forming tool can simultaneously absorb the forces of the other forming tool during forming, as they occur during the forming process. In the pertinent embodiment can be saved on elaborate supporting devices on the respective opposite sides, where the forming tool 42 does not act. Also, such a harmonic introduction of force into the storage housing 10 occurs without the occurrence of damaging force peaks.

As the 3 and 4 can show by means of a Aufsetzwerkzeuges 56, as shown in the Figure 4 the free longitudinal edge 32 of the storage housing 10, the respective cover part 20,22 are introduced into the storage housing 10 to the stop 38 in the form of the annular surface. For the pertinent insertion process, the Aufsetzwerkzeug 56 has a Zuführschräge 58, along the outer peripheral side, the cover part 20,22 can slide off. Through the use of the assembly tool 56 it is achieved that a possible seal damage of the seal 34 of the respective cover part 20,22 is avoided with certainty. In addition to the Zuführschräge 58, the Aufsetzwerkzeug 56 has a receiving space 60, in which the upper end of the storage enclosure 10 is receivable, so that the Zuführschräge 58 flush with the upper edge of the longitudinal edge 32 and the rest continuously in the receiving area 62 for the actual cover part 20th , 22 in the memory housing 10 passes.

In the embodiments of the Fig.5 and 6 is the memory housing 10 along its upper longitudinal edge 32 on the inner peripheral side and outwardly widening with the insertion beveled 50, resulting in a kind of shortened slip edge over which the respective cover part 20,22 so also introduce and then set later. The pertinent variant can be chosen if the lid seal 34 proves to be robust and should not be too vulnerable to damage.

For the modified embodiment of the Figure 7 the same reference numerals are used for the same components and the modified embodiment procedurally described only insofar as it differs significantly from the above-indicated method. In the embodiment shown, the upper lid part 20 has been held by the free longitudinal edge 32 of the storage housing 10 such that the free longitudinal edge 32 is flush along its free end with the upper second side 40 of the lid part 20. The stopper 38 for the cover part 20 is in the embodiment of the Figure 7 provided with a slope against which the cover part 20 is based in a stepped paragraph. In the recessed section-wise step 64, the ring seal 34 is again received on the outer peripheral side, wherein due to the indicated gradation of storage housing 10 and cover part 20, the possibility exists to edit the storage housing 10 for a clean contact with the sealing ring 34 at this point according to very fine and the inside the memory housing 10 to leave essentially unprocessed, provided that the delivery area for the free longitudinal edges 32 of the storage enclosure 10 is addressed.

With the aforementioned forming technique based on the free longitudinal edges 32 of the storage case 10 can thus cover parts 20,22 set in a variety of versions in register and safe and pressure-tight in the storage enclosures 10 and costly to be attached screw at this point, which are additionally secure, can be completely dispensed with.

Claims (8)

1. A method for the production of piston-type accumulators comprising an accumulator housing (10) and a separating piston (12) which can be displaced in a longitudinal direction within the accumulator housing (10) and which separates two working spaces (16, 18) within the accumulator housing (10) which is sealed at least at one of its ends by a cover part (20, 22), on the one side (40) of this cover part (20, 22) the latter being fixed via the free longitudinal edge (32) of the accumulator housing (10) which for this purpose is displaced towards the cover part (20, 22) which is inserted into the accumulator housing (10) with its side (36) lying opposite the one side (40) against a stop (38) within said accumulator housing (10) and/or the respective cover part being held by the clamping force of the displaced free longitudinal edge in its end position, characterised in that the wall thickness of the longitudinal edge (32) is reduced in relation to the rest of the accumulator housing (10) such that the transition point between these different wall thicknesses forms the stop (38) for the cover part (20) within the accumulator housing (10) and that the free longitudinal edge (32) is guided along its free end flush with or with a projection over the second side (40) of the cover part (20) positioned at the top.
2. The method according to Claim 1, characterised in that the cover part (20) is inserted with its one lower side (36) against the stop (38) within the accumulator housing (10) or that the stop (38) for the cover part (20) is provided with a slope against which the cover part (20) leans in a stepped ledge.
3. The method according to Claim 1 or 2, characterised in that for the displacement movement of the longitudinal edge (32) of the accumulator housing (10) a forming tool (42) is provided which lays the longitudinal edge (32) provided with at least one advancing slope (44) on the cover part (20) such that the latter is fixed in the manner of a force fit within the accumulator housing (10).
4. The method according to any of Claims 1 to 3, characterised in that the longitudinal edge (32) is provided on its side facing towards the respective cover part (20, 22) and outwardly with a guiding slope (50).
5. The method according to any of Claims 2 to 4, characterised in that in a common displacement movement two forming tools (42) on opposite sides of the accumulator housing (10) implement the fixing procedure for the respective end side cover part (20, 22) by acting upon the respective free longitudinal edge (32) of the accumulator housing (10).
6. The method according to any of Claims 1 to 5, characterised in that by means of a fitting tool (56) which includes the free longitudinal edge (32) of the accumulator housing (10), the cover part (20, 22) is introduced into the accumulator housing (10) up to the stop (38) by means of a directing slope (58).
7. The method according to any of Claims 1 to 6, characterised in that the longitudinal edge (32) is provided on the inner peripheral side with an outwardly extending guiding slope (50) for the cover part (20, 22).
8. The method according to any of Claims 1 to 7, characterised in that the height of the cover part (20, 22) is chosen to be at least twice as high as the free longitudinal edge (38) of the accumulator housing (10) used to clamp the cover part (20, 22).

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