Pulsation damper having a clamp sleeve and method for manufacturing a pulsation damper having a clamp sleeve

Abstract

The present invention relates to a pulsating damper (1) for damping pressure medium fluctuations in a hydraulic system, particularly an automobile brake system, comprising a plug (2) having a sleeve-shaped extension (3) and a cap-shaped elastomer membrane (4) at least partially inserted into the extension (3) of the plug (2), wherein the membrane (4) includes a collar (17) having an edge bead (5), the collar (17) of the membrane (4) is fitted onto the edge (10) of the extension (3), so that the bead (5) rests on the outside of the extension (3), and the pulsating damper (1) is characterized in that the membrane (4) is pressurized to the plug (2) via a clamp sleeve (7) that engages with the outside of the bead (5) and the extension (3).

Description

Technical Field

[0001] The present invention relates to a pulsation damper according to the preamble of the independent claim of the device and a method for manufacturing a pulsation damper according to the preamble of the independent claim of a further method.

Background Art

[0002] A pulsation damper for damping pressure medium fluctuations in a hydraulic system, particularly an automotive brake system, is known from the prior art document German Patent Application Publication No. 10 2021 202 290 A1. The pulsation damper is arranged in a bore inside a housing. The pulsation damper includes a membrane inserted into a plug, and the plug is inserted into the bore with the membrane facing forward. The membrane is pressed around the extension of the plug, and the end of the membrane is fixed outside the extension of the plug by a retaining ring. For this purpose, the membrane is vulcanized on the retaining ring. By fastening the membrane to the plug via the retaining ring, an airtight and liquidtight unit is formed. This is because the membrane inserted into the extension of the plug, together with the plug, defines the boundary of the gas space that provides the damping function. As is known, the membrane is exposed to pressure fluctuations of the working fluid on the surface on the side opposite to the gas space. A piston pump generates pressure peaks, which occur in a pulsed manner, and the pulsation damper attenuates on the path to the consumption part of the working fluid. When a pressure peak occurs, this pressure is dissipated by an elastic membrane that is pushed into the gas space. As a result, a fluid flow with reduced pressure fluctuations flows to the hydraulic consumption part.

[0003] The clamping of the pulsation damper or the gas space is important to ensure the function of the hydraulic system. Due to the tolerances of the components and various material expansions during temperature changes, leakage may occur between the membrane and the plug. However, during operation, gas does not leak from the gas space into the hydraulic system. Gas entrained in the working fluid can lead to the failure of essential components of the system. Therefore, it is important to ensure a permanent pressure-tight connection between the elastomeric membrane and the plug of the pulsation damper.

Summary of the Invention

[0004] The object of the present invention is to provide a pulsation damper for damping pressure medium fluctuations, wherein the pressure-tight connection between the plug and the membrane is improved, and to provide a method for manufacturing a pulsation damper that ensures an improved pressure-tight connection between the plug and the membrane. [Means for solving the problem]

[0005] The fundamental objective of the present invention is achieved by a method for manufacturing a pulsating damper according to the distinctive features of the independent claim of the apparatus and a pulsating damper according to the distinctive features of the independent claim of the further method.

[0006] Pulsation dampers are used in hydraulic slip-controlled automotive brake systems to dampen pressure fluctuations caused by piston pumps.

[0007] Preferred embodiments of the present invention are derived from the following description of an exemplary embodiment with reference to the dependent claims and figures. [Brief explanation of the drawing]

[0008] [Figure 1] This shows the pulsation damper inside the housing. [Figure 2a] The steps for manufacturing a pulsating damper are shown. [Figure 2b] The steps for manufacturing a pulsating damper are shown. [Figure 2c] The steps for manufacturing a pulsating damper are shown. [Figure 2d] The steps for manufacturing a pulsating damper are shown. [Figure 2e] The steps for manufacturing a pulsating damper are shown. [Modes for carrying out the invention]

[0009] Figure 1 shows an exemplary pulsation damper 1 inserted into a bore 18 of a housing 9. The housing 9 may be, for example, the housing of a piston pump. The bore 18 is exposed to, for example, working fluid coming from a piston pump. The working fluid supplied by the piston pump is under fluctuating pressure. Therefore, the pulsation damper 1 is used to dissipate high-pressure peaks. The pulsation damper 1 substantially comprises a plug 2 and a membrane 4 made of an elastomer material. The plug 2 includes a sleeve-shaped extension 3 protruding from its bottom. The membrane 4 is at least partially inserted into this extension 3. The collar 17 of the membrane 4 is pressed onto the edge 10 of the extension 3, and a bead 5 is formed on the edge side of the collar 17, which abuts the extension 3 of the plug 2 on the outside.

[0010] The membrane 4, inserted into the extension 3, together with the plug 2, defines the boundary of the damped gas space 6. Thus, the membrane 4 is exposed to gas on the side facing the plug 2 and to the working fluid on the side facing away from the plug 2. To ensure a pressurized tight connection between the plug 2 and the membrane 4, a clamp sleeve 7 is provided, for example. The clamp sleeve 7 presses the bead 5 against the extension 3 from the outside and is also pressed into itself. For this purpose, the clamp sleeve 7 is manufactured from a metallic material, preferably steel. Thus, the clamp sleeve 7 tightens the elastomer bead 5 to the extension 3 so that a permanent pressurized tight connection is formed between the membrane 4 and the plug 2. As a result, gas cannot leak from the gas space 6 into the bore 18 or into the working fluid. Here, the contour of the clamp sleeve 7 is selected so that radial and axial clamping forces act on the bead 5.

[0011] A method according to an embodiment for manufacturing such a pulsating damper 1 will be described with reference to Figures 2a to 2e. In the first method step according to Figure 2a, a membrane 4 and a plug 2 are provided. The elastomer membrane 4 is already vulcanized in its final form. Here, the cap-shaped membrane 4 includes a hollow cylindrical wall portion and a bottom portion, and the membrane is inserted into the extension 3 of the plug 2 with the bottom portion facing forward. The hollow cylindrical wall portion joins a collar 17, which is turned inward toward the outside and forms a bead 5 on its edge. The collar 17 is provided so as to be positioned around the edge 10 of the extension 3. The bead 5 is provided so that its outside is pressed compactly against the extension 3 by a clamp sleeve. For this purpose, the extension 3 includes a bead groove 11 extending around the outside below the edge 10, into which the bead 5 is inserted. Below the bead groove 11, the extension 3 includes a clamp groove 12 into which a portion of the clamp sleeve is later pressed. Furthermore, the extension 3 or plug 2 includes a clinch groove 13 in the bottom region that extends outward and circumferentially to press the plug 2 together with the housing during the clinching process.

[0012] Next, in the following step shown in Figure 2b, the membrane 4 is inserted into the extension 3 of the plug 2, and as a result, its collar 17 is pressed around the edge 10 of the extension 3, causing the bead 5 to make contact within the bead groove 11.

[0013] In the next method step shown in Figure 2c, the clamp sleeve 7 is provided on the pressing tool 19. The diameter of the clamp sleeve 7 is sized so that it can be pressed onto the extension 3 of the plug 2. This means that the inner diameter of the clamp sleeve 7 substantially matches the outer diameter of the extension 3. This outer diameter is measured below the clamp groove 12. Furthermore, the clamp sleeve 7 includes an upper tapered edge 14 that later rests on top of the bead 5 to provide a pressing force that acts substantially axially on the bead 5. In addition, the clamp sleeve 7 includes an enlarged edge 15 on the lower side that allows for centered pressing onto the extension 3 of the plug 2.

[0014] Next, in the following method step shown in Figure 2d, the clamp sleeve 7 is pressed over the bead 5 onto the extension 3, so that the clamp sleeve 7 is positioned with its tapered edge 14 on the bead 5. Here, the pressing tool 10 brings the edge 14 to axially press against the bead 5. Thus, the tapered edge 14 of the clamp sleeve 7 presses the bead 5 into the bead groove provided for this purpose. However, the conical transition region from the tapered edge 14 to the vertical diameter of the clamp sleeve 7 also brings the bead 5 to contact. Subsequently, the clamp sleeve 7 is pressed against the extension 3 by the outwardly acting clamp tool 8. For this purpose, the clamp tool 8 includes individual segments that are shifted radially inward. In detail, the clamp tool 8 acts on a predetermined position of the clamp sleeve 7 to press the clamping area of ​​the clamp sleeve 7 into the clamp groove of the extension 3 for this purpose. The resulting radial diameter reduction causes the clamp sleeve 7 to plastically deform within the clamping area, thus imparting a radially acting clamping force to the extension 3. As a result, the film 4 or its bead 5 is compactly fixed to the plug 2 or its extension 3. The resulting connection of the plug 2 to the film 4 is considered compactly tight. It is unaffected by any part tolerances, and differences in material expansion during temperature changes are not a problem.

[0015] Finally, in the further method step shown in Figure 2e, the pulsating damper 1, assembled according to the example, is inserted into the bore 18 of the housing 9. By the clinching tool 16, the plug 2 is deformed by clinching into the bore 18, and thus firmly and similarly pressure-tightly connected to the housing 9. [Explanation of Symbols]

[0016] 1. Pulsating damper 2 plugs 3 Extension 4 membrane 5 Beads 6. Gas space 7 Clamp Sleeves 8 Clamping Tools 9 Housing 10 Edge 11 Bead groove 12 Clamp groove 13 Crimp groove 14 Tapered edge 15 Enlarged edge 16 Crimp tool 17 Color 18 Bore 19 Pressing tool

Claims

1. A pulsation damper (1) for damping pressure medium fluctuations in a hydraulic system, particularly an automobile brake system, comprising a plug (2) having a sleeve-shaped extension (3) and a cap-shaped elastomer membrane (4) at least partially inserted into the extension (3) of the plug (2), wherein the membrane (4) includes a collar (17) having an edge bead (5), and the collar (17) of the membrane (4) is pressed around the edge (10) of the extension (3), so that the bead (5) abuts against the extension (3) on the outside, wherein the membrane (4) is pressurized to the plug (2) via a clamp sleeve (7) acting on the outside of the bead (5) and the extension (3).

2. The pulsating damper (1) according to claim 1, characterized in that the extension (3) of the plug (2) includes a bead groove (11), the bead groove (11) extends outward and circumferentially, and the bead (5) of the membrane (4) is located within the bead groove (11).

3. The pulsating damper (1) according to claim 1 or 2, characterized in that the extension (3) of the plug (2) includes a clamp groove (12), the clamp groove (12) extends outward and around the periphery, and the clamp area of ​​the clamp sleeve (7) is pressed into the clamp groove (12).

4. The pulsation damper (1) according to any one of claims 1 to 3, characterized in that the clamp sleeve (7) includes a tapered edge (14) that provides an axial clamping force to the bead (5).

5. The pulsation damper (1) according to any one of claims 1 to 4, characterized in that the clamp sleeve (7) includes an enlarged edge portion (15), and the clamp sleeve (7) is inserted onto the extension portion (3) by the enlarged edge portion (15).

6. A method for manufacturing a pulsating damper (1), - A step of providing a plug (2) having an extension (3), - A step of providing a film (4) made from an elastomer material having a folded bead (5), - A step of inserting the film (4) into the extension (3) of the plug (2), wherein the bead (5) abuts against the extension (3) on the outside. Includes, - Steps of providing a clamp sleeve (7) and pressing the clamp sleeve (7) axially on the extension (3), - A step of pressing the clamp sleeve (7) axially with a pressing tool (19), wherein as a result, a portion of the clamp sleeve (7) is pressed axially against the bead (5), - A step of pressing the clamp sleeve (7) radially with the clamp tool (8), so that as a result the clamp area of ​​the clamp sleeve (7) is pressed against the extension (3), and A method characterized by...

7. The method according to claim 6, characterized in that the bead (5) is pressed into the bead groove (11) of the extension (3) by the tapered edge (14) of the clamp sleeve (7).

8. The method according to claim 6 or 7, characterized in that the clamping area of ​​the clamping sleeve (7) is pressed into the clamping groove (12) of the extension (3).

9. The method according to any one of claims 6 to 8, characterized in that the film (4) is first vulcanized into a cap-like shape having an inverted collar (17) with edge beads (5).

10. The method according to any one of claims 6 to 9, characterized in that the clamp sleeve (7) is manufactured by deep drawing prior to the method step.

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