JP5698247B2 - Hydropneumatic accumulator - Google Patents

Description

  The invention relates to a hydropneumatic pressure accumulator with a movable isolation element arranged in a pressure accumulator housing, the isolation element comprising a first working chamber, preferably a gas chamber, a second working chamber. And is formed by a diaphragm made of a flexible material, in particular an elastomer, with a housing opening located in the accumulator housing that forms an inlet and outlet to the liquid chamber, The flow in the opening is controllable by a valve device which can be transferred to a release position and a closed position, the valve device having a valve body located on the surface part of the diaphragm, the valve body being located in the housing opening The valve device is moved to a closed position when approaching the valve seat, the valve device having a bypass device that allows restricted flow through the housing opening in the closed position. Pneumatic accumulator on. Furthermore, the present invention relates to a method for manufacturing such a hydropneumatic pressure accumulator.

In such a diaphragm-type accumulator, the working chamber of the gas side are usually working gas under high preload, in particular pre-filled with N _2. The magnitude of the preload may be on the order of 100 bar. In operation, when hydraulic pressure is connected to a housing opening having an oil connection and the hydraulic pressure of the connected hydraulic system is within a specified operating pressure range, the flexible diaphragm is a liquid chamber that guides the hydraulic pressure. In this region, the volume decrease caused by lifting from the inner wall of the accumulator housing and causing the diaphragm to warp away from the inner wall on the liquid side of the accumulator housing causes the original prefill pressure p ₀ to be reduced to the pressure p ₁ (instantaneous). The pressure balance of the diaphragm is formed.

If no or little fluid pressure is formed in the housing opening, for example if no hydraulic pressure is connected to the oil connection, or if the hydraulic pressure is no pressure, the diaphragm is subjected to the prefill pressure p ₀ . It is applied to the inner wall of the liquid chamber. The surface portion moved toward the housing opening closes the housing opening by the valve body of the valve device located on this surface portion.

Since the diaphragm type accumulator is opened in the hydraulic device, and after the desired prefill pressure p ₀ is formed in the gas chamber, the opening that forms the oil connection is closed by the diaphragm. It is advantageous only in that it does not have an opening. Thus, the prefilled pressure accumulator can be handled, stored and transported without the risk of impurities or foreign objects entering through the housing opening forming the oil connection.

On the other hand, during the operation of the pressure accumulator built into the hydraulic device, problems may arise due to the closing of the housing opening by the valve device. During operation, for example, a relatively sudden pressure drop occurs at the oil connection and the valve body is moved suddenly into the housing opening so that such a pressure drop results in a rapid closing action based on the flexibility of the diaphragm, A so-called “Oeltaschen” is formed, leaving a residual volume of hydraulic oil in the liquid chamber in the wall region separated from the housing opening. In other words, in this case, the diaphragm is lifted slightly in proportion to the volume of the oil pocket, rather than being entirely applied to the inner wall of the accumulator housing in the oil pocket region. Thereby, the volume of the gas chamber is correspondingly reduced with respect to the maximum volume defined by the shape of the accumulator housing. As a result, the gas pre-pressure in the gas chamber does not correspond to the prescribed value p ₀ but to a higher gas pre-pressure despite the absence of fluid pressure in the oil connection. Thereby, the response pressure of the pressure accumulator, that is, the open pressure p ₁ also increases. Thus, if rapid draining and filling occurs many times, accumulator “expansion” with increasing p ₁ can occur. Here, if the test process as performed by the system controller in the hydraulic device is carried out on the gas side, the gas pre-pressure is erroneously too high when checking whether the pre-fill pressure corresponds to the value p ₀ Is detected. Such pressure is corrected in some cases by the system.

  In order to provide a remedy here, i.e. the presence of a valve device located in the housing opening on the oil side, in the absence of fluid pressure, different gas pre-pressures can lead to errors during the test process In order to avoid the possibility of the occurrence of gas in the gas chamber, a valve device of the type mentioned at the beginning is formed so that, in the closed position, a bypass device is formed which allows restricted flow through the housing opening. This is already known on the basis of Patent Document 1. In this known solution, grooves are provided at the edges of the housing opening of the accumulator housing, which serve as a valve seat for the valve body, and these grooves are the valve seat surface of the housing opening of the accumulator housing. By machining into the forming edge, a bypass device is formed. The formation of the groove increases the manufacturing cost when manufacturing the housing. In addition, if the material intended for the valve body has a corresponding followability, the material of the valve body may be pushed into the groove. This will result in tight closing of the valve device and disabling the bypass device.

  In addition to the diaphragm type accumulator, a hydropneumatic accumulator in the form of a bellows type accumulator is also known in the prior art. In the case of the bellows type accumulator, a bellows that can be expanded in the longitudinal direction extends inside the accumulator housing. One free end of the bellows is typically coupled to the inside of the accumulator housing and the other free end typically has a plate-like valve closure member. This valve closing member can also close and release the hydraulic fluid connection of the accumulator housing. Inside the bellows, in this case, a working gas, in particular in the form of nitrogen gas, is usually arranged for comparison with the diaphragm-type accumulator means. A representative of such bellows type accumulator means is shown in Patent Document 2. On the lower surface of the plate-shaped valve closing member, an annular elastomer seal edge protrudes in a state of extending toward the liquid inflow opening of the pressure accumulator housing. This seal edge has individual ring segment projections for better shock attenuation. However, the entire extent of these protrusions completely and completely surrounds the liquid opening in a closed position that blocks the liquid opening. The advantageous “bypass device” mentioned at the outset cannot be achieved using such known bellows accumulator means.

German Patent Application Publication No. 202007008175 European Patent Application No. 1052412

  Starting from such prior art, the task of the present invention is to provide a pressure accumulator of the type considered, which stands out especially in simple construction and in particularly good operating characteristics.

  In the hydropneumatic accumulator of the type mentioned at the outset, such a problem is according to the invention that the valve body is at least one on the face of the valve body facing the valve seat in order to form a bypass device. The projection is solved by forming a spacer on the valve seat that allows flow.

  Thus, a bypass device is realized that ensures that the entire oil content in the oil chamber flows out by simply applying the shape of the valve body without requiring modification of the pressure accumulator housing. Such a structure allows a particularly rational production of the pressure accumulator.

  In an advantageous embodiment, at least two protrusions may be provided on the face of the valve body facing the valve seat, with a gap between the protrusions allowing flow.

  This arrangement is particularly advantageous because a plurality of protrusions can be distributed in a regular positional relationship on the face of the valve body. Thereby, the protrusion forms a spacer that supports the valve body in a state where it does not tilt with respect to the valve seat surface.

  In a particularly advantageous embodiment in which the face of the valve body is circular, these projections may be arranged along a single concentric circumference extending at a slight distance from the periphery of the face. The protrusion may be formed of a slit-like annular body.

  In such a configuration, the slit annulus has four identical partial ring segments, and between these partial ring segments is less than half the circumferential length of the partial ring segments. A gap having a length may be provided. This allows the projections that serve as spacers to obtain satisfactory durability while producing favorable flow characteristics.

  Such a protrusion may have a taper towards its free end starting from its base formed on the face of the valve body.

  The subject of the invention is also a method for producing a hydropneumatic pressure accumulator as described in the preamble of claim 1, which method has the method steps and characteristics of claim 9.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing an embodiment of the hydro accumulator of the present invention. FIG. 2 is an enlarged perspective view showing the valve body of the valve device of the embodiment relative to the actual embodiment. FIG. 3 is a plan view showing the valve body on the scale of FIG. 4 is a cross-sectional view showing the valve body along a cutting line IV-IV- in FIG. 3. FIG. 5 is a partial cross-sectional view showing only the housing opening of the embodiment of the accumulator and the region of the valve device cooperating therewith in an enlarged view of FIG. FIG. 6 is a cross-sectional view showing an incomplete state of an injection mold for applying a shape to a diaphragm when a pressure accumulator is manufactured using the method according to the present invention.

The illustrated hydro accumulator is a so-called diaphragm accumulator in which a partition wall in the form of an elastic diaphragm 3 is disposed in a pressure accumulator housing indicated by reference numeral 1 as a whole. The diaphragm 3 separates the interior of the housing 1 into a liquid chamber 5 and a gas chamber 7. The housing 1 includes an upper housing shell 9 and a lower housing shell 11 as viewed in FIG. Each of these housing shells has a round shell shape with an inner wall curved in a substantially hemispherical shape. A gas connecting portion 13 is located at an end of the accumulator housing 1 opposite to the liquid chamber 5, that is, an end belonging to the gas chamber 7. The gas chamber 7 can be prefilled with a working gas, particularly N ₂ gas, through this gas connection. An end portion corresponding to the liquid chamber 5 has a housing opening 15 that opens into the liquid chamber 5. An oil connecting portion 17 is attached to the housing opening 15 on the outside. The pressure accumulator can be connected to oil pressure (not shown) via the oil connection 17.

  The upper housing shell 9 and the other housing shell 11 that are abutted with each other along the joint portion 19 are coupled to each other by an electron beam welding method. A fixing ring 21 is fixed to the inner wall in the region of the joint portion 19. The fixing ring 21 forms a support for the diaphragm 3. A thickened peripheral bead 23 of the diaphragm 3 is fitted in an annular groove 25 of the fixing ring 21. This fixing ring is sealed on the inner wall of the housing 1 via a sealing element 27.

FIG. 1 shows a diaphragm type accumulator in one operating state. In this operating state, the diaphragm 3 is located at an intermediate position where a pressure balance is formed on both sides of the diaphragm 3. The reason why the pressure balance is formed is that a hydraulic pressure (not shown) connected to the oil connecting portion 17 generates a fluid pressure corresponding to the pressure formed in the gas chamber 7. In a state where little or no hydraulic pressure is formed in the oil chamber 5, the diaphragm 3 moves downward as viewed in FIG. 1 and is applied to the inside of the lower housing shell 11. In this case, the valve element 29 located in the middle surface area of the diaphragm 3 covers the valve seat 33 provided at the peripheral edge 31 of the housing opening 15. In such an operating state corresponding to the minimum volume of the oil chamber 5 and the maximum volume of the gas chamber 7, a prefill pressure p ₀ is formed in the gas chamber 7. Its size is uniquely selected depending on the application, and this is the pre-filling pressure formed in the gas chamber 7 as a preset value for the hydro accumulator while the liquid chamber 5 is free of pressure. During continuous operation, a test is carried out in a practical way to determine whether the prefill pressure p ₀ is unchanged and correspondingly whether the accumulator has a constant operating characteristic.

  During operation, when a very rapid and rapid pressure drop occurs in the liquid chamber 5, the diaphragm 3 moves rapidly toward the housing opening 15. As a result, the valve body 29 is applied to the valve seat 33. Thereby, the valve body 29 forms the component part of a valve apparatus.

  In order to avoid the possibility of the housing opening 15 being closed before the entire volume 5 of oil flows out when the diaphragm 3 moves correspondingly rapidly or rapidly, a residual volume is left in the liquid chamber 5. In order to prevent the oil pocket from being formed, the valve body 29 is formed so that a bypass device is formed, as best seen in FIGS. The bypass device allows a limited flow through the housing opening 15 when the valve device is in the closed position, so that any residual oil volume can flow out of the liquid chamber 5. In order to be able to bypass the valve device, a protrusion is provided, which is specially formed on the surface 34 facing the valve seat 33 and extends from the plane of the circular surface 34. Its special contour can be seen most clearly from FIGS. These protrusions forming a spacer with respect to the valve seat 33 prevent the face 34 of the valve body 29 from coming into direct contact with the valve seat 33. As most clearly shown in FIGS. 2 and 3, the protrusion is formed by a partial ring segment 37 of a slit ring. These segments extend along one concentric circumference adjacent to the peripheral edge 39 of the circular valve body 29. Between the partial ring segments 37, each having the same length, a gap 41 is located. Since these gaps have the same length, the protrusions are arranged on the surface 34 in a regular positional relationship. As shown in FIG. 5, when the valve device is in the closed position, the gaps 41 each form a restricted fluid path between the liquid chamber 5 and the housing opening 15.

  As is apparent from FIGS. 2 to 4, the partial ring segment 37 has a tapered shape starting from its base formed on the surface 34 toward the free end. This shape is defined by a cylindrical surface 43 (see FIGS. 2 and 4) on the radially outer side of the partial ring segment and by a conical surface 45 on the inner side. Are defined by a narrow end face 47 parallel to the face 34 of the valve body 29. In the illustrated embodiment, the length of each gap 41 is less than half the circumferential length of the partial ring segment 37.

  In the illustrated embodiment, the protrusions formed by the partial ring segments 37 are provided in a regular arrangement relationship on the surface 34, and the protrusion gap 41 forms a passage for flow. Needless to say, spacers having other shapes and arrangement relationships may be provided as well as a single, integral projection (not shown). In the case described above, the breakage or notch provided in the protrusion can also form a flow path for the flow of the valve device.

  As can be seen from FIG. 1 and more clearly from FIG. 5, the valve body 29 may be formed on the peripheral edge 39 defining the surface 34 with an edge 51 slightly projecting from the plane of the surface 34. When the valve body 29 having such a peripheral edge 51 is used, a pressure accumulator can be manufactured according to a particularly advantageous manufacturing method. As shown only schematically in FIG. 6, when manufacturing the diaphragm 3 in which the valve body 29 is formed, the valve body 29 having the edge 51 is formed by an injection mold (of which only the mold portion 53 is shown in FIG. 6). ), And then the elastomer 51 is injected with the valve body 29 disposed therein to form the diaphragm 3, so that the edge 51 is formed on the wall of the mold 53. By being applied, it forms a sealing edge, which effectively prevents the elastomer from reaching uncontrolled below the face 34 of the valve body 29.

Claims (9)

Hydropneumatic accumulator with a movable isolation element arranged in the accumulator housing (1), said isolation element comprising a first working chamber, preferably a gas chamber (7), 2 separated from the liquid chamber (5) as a working chamber and formed by a diaphragm (3) made of a flexible material, in particular an elastomer, in the pressure accumulator housing (1), the liquid chamber (5 A housing opening (15) forming an entry / exit path is located, the flow in the housing opening being controllable by a valve device capable of transitioning to a release position and a closed position, the valve device comprising the diaphragm (3) has a valve body (29) located on the surface portion, and when the valve body approaches the valve seat (33) located in the housing opening (15), the valve device is moved to the closed position. , Kiben apparatus, and have a bypass device which enables distribution which is limited through the housing opening in the closed position,
The valve body (29) has at least one projection (37) on a surface (34) of the valve body facing the valve seat (33) to form the bypass device; In the hydropneumatic pressure accumulator, the protrusion forms a spacer that enables the flow with respect to the valve seat (33) .
The valve body (29) has an edge (51) slightly protruding from the plane of the surface (34) at the peripheral edge (39) defining the surface (34) facing the valve seat (33). Hydropneumatic accumulator characterized by being formed as follows .   At least two protrusions (37) are provided on a surface (34) of the valve body (29) facing the valve seat (33), and a gap (which allows the flow) between the protrusions ( 41. The hydropneumatic accumulator according to claim 1, characterized in that 41) is located.   The plurality of protrusions (37) are arranged in a regular positional relationship and distributed on the surface (34) of the valve body (29), according to claim 1 or 2. Hydropneumatic pressure accumulator.   The surface (34) of the valve body (29) is circular, and the protrusion (37) is disposed along one concentric circumference extending at a slight distance from the periphery of the surface (34). The hydropneumatic pressure accumulator according to any one of claims 1 to 3, wherein the accumulator is a hydropneumatic pressure accumulator.   The hydropneumatic pressure accumulator according to any one of claims 1 to 4, wherein the projection is formed by a slit-like annular body (37).   The slit ring has four identical partial ring segments (37), and is less than half the circumferential length of the partial ring segments (37) between the partial ring segments. The hydropneumatic pressure accumulator according to any one of claims 1 to 5, characterized in that a gap (41) having a length is provided.   Each of the protrusions (37) has a taper toward its free end (47) starting from its base formed on the face (34) of the valve body (29). The hydropneumatic accumulator according to any one of claims 1 to 6.   The projection formed by the slit-shaped annular body (37) is defined on one side by a conical surface (45) starting from the surface (34) of the valve body (29) and on the other side because of the taper. Then, it is defined by the cylindrical surface (43), and the conical surface (45) and the cylindrical surface (43) are narrow in parallel to the surface (34) of the valve body (29). The hydropneumatic accumulator according to any one of claims 1 to 7, characterized in that it is connected by an end face (47). A method of manufacturing a hydropneumatic accumulator as described in the premise of claim 1,
a) providing a valve body (29) having at least one protrusion (37) located on a surface (34) facing the valve seat (33);
b) placing the valve element (29) in an injection mold (53) for forming a flexible diaphragm (3) forming a movable isolation element; and c) the valve element (29) Injecting the elastomer forming the diaphragm (3) so that the surface (34) facing the valve seat (33) is exposed and bonded into the elastomer. In a method of manufacturing a matic pressure accumulator,
The valve body (29) having a protruding edge (51) at the peripheral edge defining the surface (34) is used, and the protruding edge cooperates with the wall of the injection mold (53) A method of manufacturing a hydropneumatic pressure accumulator characterized by forming a member.

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