Piston type energy accumulator
By adopting a damping piston with a check valve in a piston accumulator, the problems of insufficient response characteristics and poor damping effect in the prior art are solved, and better sealing and fluid control effects are achieved , suitable for hydraulic accumulators of different sizes.
Patent Information
- Application Number
- CN202290000841.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Priority Date
- 2022-01-12
- Filing Date
- 2022-12-20
- Publication Date
- 2024-12-31
- Estimated Expiration
- 2032-12-20
AI Technical Summary
The existing piston accumulators have insufficient response characteristics when fluid flows in or out, and the damping effect of the end position of the partition piston is poor, and the design of the check valve leads to sealing problems and vortex current phenomena.
Design a piston accumulator with a damping piston with a check valve to block the fluid in the closed position by forming a cylindrical throttling gap in the accumulator housing and using the valve ball loaded by the accumulator to block the fluid in the closed position. The path, in the open position release path, the damping piston achieves a constant throttling gap width in the fluid joint, and further dampens the partition piston movement in combination with the annular gap, and the damping device is fixed with the clamping ring of the partition piston through the insert body, simplifying assembly and reducing cost.
Significantly improve the damping effect at the end of the piston, realize the sealing of fluid flow and eddy current reduction, enable quick and reliable control of the loading and unloading process of hydraulic accumulators, and the design of the damping device is easy to manufacture and adapt to different sizes. Hydraulic energy accumulator.
Smart Images
Figure CN222277059U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a piston accumulator, which has an accumulator housing, in which a separating piston is guided in a longitudinally displaceable manner, the separating piston separating two fluid chambers from each other, in particular separating a fluid chamber containing a working gas from another fluid chamber containing a liquid, such as hydraulic oil, and the separating piston has a damping piston with a check valve, and the damping piston can be moved into a fluid connection in the accumulator housing while forming a throttling gap. Background Art
[0002] EP 0 286 777 A2 discloses a piston-cylinder unit of the same type with piston end position damping, which has a damping piston protruding on the end face of the piston, which can be moved into a damping chamber arranged at the opposite cylinder end while forming a damping gap that tapers conically in the direction of the fluid connection, and for the introduction of the return lifting movement of the piston, a flow path is provided, which leads from the fluid connection for the pressure oil to the pressure chamber adjacent to the main piston face of the piston in the accumulator housing, bypassing the damping gap, and includes a non-return valve. This flow path, which can be controlled by the non-return valve, extends inside the piston between an inlet opening at the front end of the damping piston, which is designed as a hollow sleeve, and a through opening in the form of a transverse channel that leads from the interior of the sleeve to the outside. The non-return valve used in this regard has a solid valve plate that can be controlled by an accumulator in the form of a compression spring, which controls a large opening cross section in the damping piston, which leads to leaks in the closed position and is accompanied by eddies in the flow path when the valve is open. Furthermore, due to the inertial properties of the valve plate, rapid opening and closing processes are excluded. Utility Model Content
[0003] Starting from the prior art, the object of the invention is therefore to further improve the known solution in order to provide a piston accumulator which, in addition to an improved response behavior when fluid flows into or out of the hydraulic accumulator, also has an improved end position damping for the separating piston.
[0004] To this end, the utility model proposes a piston accumulator, which has an accumulator housing, a separating piston guided in the accumulator housing in a longitudinally displaceable manner, the separating piston separating two fluid chambers from each other, and the separating piston having a damping piston with a check valve, the damping piston being able to move into a fluid connection in the accumulator housing while forming a throttling gap, the throttling gap being a cylindrical annular space formed by adjacent walls of the accumulator housing and the damping piston, the check valve having a valve ball loaded by the accumulator, the valve ball being in its closed position A fluid path between a centrally located blocking fluid connection and a piston fluid chamber located between the separating piston and the accumulator housing is released in its open position, and when viewed in the direction of the piston fluid chamber, the damping piston transitions into a widened portion having an annular surface while forming a shoulder, wherein the annular surface forms an annular gap when the separating piston abuts against a component of the accumulator housing, the gap size of the annular gap being greater than the gap size of the throttling gap, wherein the annular surface is part of an insert that accommodates a check valve and is fixed in the accommodating portion of the separating piston.
[0005] A constant throttling gap width is achieved over the entire engagement length of the damping piston in the fluid connection, which achieves significantly improved end position damping, by virtue of the fact that the throttling gap is a cylindrical annular space formed by adjacent walls of the accumulator housing and the damping piston, and the nonreturn valve has a valve ball loaded by the accumulator, which in its closed position blocks the fluid path between the fluid connection and the piston fluid chamber between the separating piston and the accumulator housing and in its open position releases the fluid path. This achieves significantly improved end position damping. Since there is no need to take into account the gap geometry with a tapered section, which changes constantly as shown in the prior art, the engagement length of the damping piston in the fluid connection can be selected to be very long within a predetermined range (depending on the geometry of the hydraulic accumulator to be maintained), thereby achieving significantly improved piston end position damping in combination with a constant gap size over the entire engagement length. In addition, the valve ball of the nonreturn valve can achieve an improved valve seat geometry, which has improved sealing in the closed position and reduced turbulence in the open position when flow passes through. Furthermore, due to the low inertia of the correspondingly small-sized valve or closing ball, the fluid flow occurring during charging and discharging of the hydraulic accumulator can be controlled quickly and continuously and reliably. This has no analogues in the prior art.
[0006] In a preferred embodiment of the piston accumulator according to the invention, it is provided that the damping piston is formed by a hollow cylinder, which, at least in one of its damping positions, establishes a fluid path between the fluid connection and the nonreturn valve by means of its hollow cylindrical passage. The diameter of the hollow cylinder in the damping piston is substantially equal to the diameter of the valve closing ball, so that when the accumulator is charged with fluid, such as hydraulic oil, the valve ball is centrally hit by the flow and can therefore be lifted from its valve seat in an unhindered and defined manner in the associated valve housing.
[0007] In another preferred embodiment of the piston accumulator according to the invention, it is provided that, viewed in the direction of the piston fluid chamber, the damping piston transitions into a widened portion with an annular surface while forming a shoulder, which, when the separating piston abuts against a component of the accumulator housing, such as a housing cover, forms an annular gap, the gap size of which is greater than the gap size of the throttling gap. Thus, until the separating piston completely abuts against the adjacent upper side of the housing cover in its lower displacement position when the accumulator is unloaded, the movement of the separating piston is further damped by the annular gap, so that the throttling gap and the annular gap jointly assume the damping of the movement of the separating piston.
[0008] In another preferred embodiment of the piston accumulator according to the invention, it is provided that the annular surface is part of an insert body which accommodates the non-return valve and is preferably fixed in the receptacle of the separating piston by means of a clamping ring between the insert body and the separating piston. Since the non-return valve is an integral component of the insert body, the damping device can be connected to the separating piston as a whole from a central point, in particular from the underside of the separating piston, which is very assembly-friendly and involves few work steps. In this respect, the piston accumulator solution according to the invention can also be manufactured cost-effectively.
[0009] In another preferred embodiment of the piston accumulator according to the invention, it is provided that the non-return valve is designed as a valve cartridge, whose valve housing is screwed into the insert body and the valve ball is guided in the valve housing under constant load by an accumulator, preferably in the form of a compression spring. Such valve cartridges are common on the market and can be adapted to different hydraulic accumulator sizes, in particular in terms of connection geometry, which contributes to a functionally reliable and cost-effective design of the overall end position damping.
[0010] In this case, the valve housing preferably has at least one first transverse channel, which can be guided in the direction of an associated second transverse channel in the insert body by means of a valve ball of the non-return valve. In this case, the valve housing preferably has a recess on the outer circumference, preferably in the form of a valve annular space, into which the corresponding first transverse channel of the valve housing opens from one side and the corresponding associated second transverse channel in the insert body opens from the opposite side. In this way, an overall flow guidance is achieved by the valve housing together with the insert body. By deflecting the vertically flowing fluid flow by approximately 90° when charging the energy accumulator, it is deflected in the direction of the piston fluid chamber into the transverse guide, which is particularly advantageous in terms of energy and allows for immediate actuation of the dividing piston directly during the charging process.
[0011] In another preferred embodiment of the piston accumulator according to the invention, it is provided that the separating piston defines a cavity-like recess on its side facing the fluid connection, the cavity-like recess opens into the bevel in the direction of the clamping ring, and the bore axis of the corresponding second transverse channel in the insert body is aligned with the wall of the separating piston that at least partially defines the recess in the separating piston and the bevel opens into the recess at the wall. By means of the preferably circumferential bevel, the clamping ring for fixing the insert body can be reliably positioned in the separating piston and the bevel can also serve as an oncoming flow aid for directly converting the transverse force of the fluid flow into a lifting movement of the separating piston within the scope of the accumulator charging process.
[0012] As already explained, it is particularly preferably provided that the axial length of the damping piston is greater than the corresponding height of the piston fluid chamber in the separating piston, which is at least partially penetrated by the insert body. Practical tests have shown that with this length-height design, particularly good damping properties are produced during the discharge process of the accumulator and in the opposite direction of charging the accumulator, the separating piston is displaced unhindered in the direction of the fluid chamber containing the working gas and is prestressed in the process.
[0013] The utility model also relates to a method for operating a piston accumulator, which comprises the following method steps:
[0014] - when unloading the piston accumulator, the volume flow is throttled by forming a hollow cylindrical throttling gap between the damping piston and parts of the accumulator housing,
[0015] - When the piston accumulator is charged, the check valve integrated in the separating piston is opened by the valve ball charged by the accumulator, the throttling gap is bypassed due to the pressure difference generated in the throttling gap, and this causes
[0016] Applying fluid pressure to the entire free piston cross section in order to displace the dividing piston directly in the direction of the further fluid chamber containing the working gas. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The piston accumulator according to the present invention will be described in more detail below with reference to the accompanying drawings and with the aid of embodiments. In the accompanying drawings:
[0018] The only Figure 1 The lower part of an otherwise conventional piston accumulator, as shown by way of example in EP 0 286 777 A2, is shown in longitudinal section. DETAILED DESCRIPTION
[0019] Figure 1 The lower part of a piston accumulator is shown, which has a hollow cylindrical wall 8 of an accumulator housing, which is designated as a whole by 10, and in which a separating piston 12 is guided in a longitudinally displaceable manner, which separates two fluid chambers 14, 16 from each other, in particular a fluid chamber 14 with a working gas, such as nitrogen, from a further fluid chamber 16 with a liquid, such as hydraulic oil. In addition, the separating piston 12 has a damping piston 18 with a non-return valve 20 at the end of its free end face. The damping piston 18 can be moved into a fluid connection 24 in the accumulator housing 10 while forming a throttling gap 22, Figure 1 The separating piston 12 is shown in the maximum lowest position in the accumulator housing 10 (when the fluid flow from the fluid chamber 16 in the direction of the fluid connection 24 is subject to maximum throttling). Figure 1 The position of the separating piston 12 shown in corresponds to the maximum unloading of the hydraulic accumulator as a whole. Through the internal thread 26 in the fluid connection 24, the piston accumulator can usually be connected to a hydraulic circuit of a common construction type not shown by means of a pipe not shown.
[0020] If Figure 1 As can also be seen, the throttling gap 22 is a cylindrical annular space or a hollow cylinder filled with fluid, which is formed by an adjacent wall 28 of the accumulator housing 10 in the form of a housing cover 30 and an oppositely adjacent wall 32 of the damping piston 18. The housing cover 30 is screwed into the hollow cylindrical wall 8 of the accumulator housing as part of the accumulator housing 10 at the bottom side and is sealed relative to the rest of the accumulator housing 10 by an annular seal not shown in detail in the annular groove 31. The separating piston 12 has two annular grooves 33 on the outer circumference for accommodating sealing rings and guide strips not shown in detail, of which only the upper one is marked with 33. The check valve 20 has a valve ball 36 which is continuously loaded by an accumulator in the form of a compression spring 34, which is in the form of a compression spring 34. Figure 1 In the closed position shown in FIG. 1 , the fluid path between the fluid connection 24 and the piston fluid chamber 38 between the separating piston 12 and the accumulator housing 10 or the housing cover 30 is blocked, and in the open position, this fluid path is released against the action of the compression spring 34. In the present case, the piston fluid chamber 38 is formed by a chamber-like recess on the underside of the separating piston 12, which is surrounded on the outer circumference at the level of the sealing ring system in the annular groove 33 by the wall of the separating piston 12.
[0021] If Figure 1 It is furthermore apparent that the damping piston 18 is formed by a hollow cylinder which, at least in one of its damping positions (in Figure 1 The damping piston 18 (in the fully damped position) with its hollow cylindrical passage 40 establishes a fluid path between the fluid connection 24 and the non-return valve 20 and its valve ball 36. When viewed in the direction of the piston fluid chamber 38, the damping piston 18, which is reduced in diameter, transitions into a widened portion with an annular surface 44, which is enlarged in diameter compared thereto, with the formation of a shoulder 42, according to the Figure 1 , the annular surface forms an annular gap 46 when the separating piston 12 bears against a component in the form of the housing cover 30 of the accumulator housing 10 , the gap dimension of which is preferably selected to be greater than the free gap dimension of the throttle gap 22 .
[0022] The annular surface 44 is part of an insert 48, which accommodates the non-return valve 20 as a whole and is held in a hollow cylindrical receptacle 50 of the separating piston 12 by means of a clamping ring 52 between the insert 48 and the separating piston 12. The non-return valve 20 is designed as a valve cartridge, which is screwed with its valve housing 54 into the insert 48 using a hexagon socket screw 55 and is fixed according to the invention. Figure 1, the valve ball 36 is held in its closed position in a sealing manner on a valve seat 56 in the valve housing 54 under the action of the compression spring 34. The valve housing 54 has a first transverse channel 58, which is diametrically opposed to one another with respect to the longitudinal axis 60 of the hydraulic accumulator and is directly connected to the valve ball 36 and can be actuated by the valve ball. Instead of a pair of first transverse channels 58, a different number of first transverse channels 58 can also be provided, in particular only a single first transverse channel 58 can also be provided. The respective first transverse channel 58 in the valve housing 54 opens in the direction of an associated further second transverse channel 62 in the insert body 48. Between the associated pairings of the first transverse channel 58 and the second transverse channel 62, the valve housing 54 has a recess 64 on the outer circumference, preferably in the form of a valve annular space, into which the respective first transverse channel 58 of the valve housing 54 opens from one side and the respective associated second transverse channel 62 in the insert body 58 opens from the opposite other side. The separating piston 12 defines, on its side facing the fluid connection 24, a hollow cavity-like recess as part of the piston fluid chamber 38, which opens in the direction of the clamping ring 52 into a bevel 66 in the separating piston 12, which extends conically upward in the direction of the longitudinal axis 60. In this case, the bore axis of the corresponding second transverse channel 62 in the insert body 48 is aligned with the upper boundary wall of the recess in the separating piston 12, into which the bevel 66 extending circumferentially in the separating piston 12 opens. It is particularly important for the piston accumulator solution according to the invention that the axial length of the damping piston 18 is at least greater than the corresponding height of the piston fluid chamber 38 formed by the recess in the separating piston 12, which is at least partially penetrated by the insert body 46, as long as the damping piston is engaged with the part of the fluid connection 24.
[0023] Figure 1 The piston accumulator shown in can then be operated as follows with the aid of the arrangement according to the invention:
[0024] - when unloading the piston accumulator, the volume flow is throttled by forming a hollow cylindrical throttling gap 22 between the damping piston 18 and parts of the accumulator housing 10, wherein the fluid is displaced from the fluid chamber 16 via the throttling gap 22 in the direction of the fluid connection 24 which remains unpressurized due to the associated downward movement of the separating piston 12. Further throttling is achieved here by means of an annular gap 46 between the insert body 48 and the adjacent wall upper side of the housing cover 30;
[0025] When the piston accumulator is charged, the check valve 20 integrated in the separating piston 12 is opened by means of the valve ball 36 loaded by the compression spring 34, and the throttling gaps 22, 46 are bypassed due to the pressure difference generated in particular in the throttling gap 22. Due to the fluid pressure present in the fluid connection 24, the check valve 20 is opened and the fluid flows through the hollow cylindrical passage 40 and through the interior of the valve housing 54 in the direction of the first transverse channel 58 and the second transverse channel 62, which are connected in a fluid-conducting manner to the recess 64 of the valve housing 54. In this way, the fluid under pressure reaches the piston fluid chamber 38 via the fluid connection 24 and flows in the direction of the piston fluid chamber 38. Figure 1 In the direction of observation, the separating piston 12 is lifted upward. In the case of further displacement movement overcoming the effect of the working gas in the fluid chamber 14, the fluid volume on the liquid side increases with the fluid chamber 16. This subsequently causes
[0026] - Fluid pressure is applied to the entire free piston cross section in order to displace the separating piston 12 directly in the direction of the further fluid chamber 14 containing the working gas. As soon as the damping piston 18 completely releases the fluid passage 24 due to the displacement movement of the separating piston 12 in the direction of the fluid chamber 14, more fluid will flow from the hydraulic circuit in the direction of the fluid chamber 16. In this operating position, the hydraulic accumulator is then used again for the described unloading process.
[0027] The damping valve, which is designated as a whole by 68, is located in the region of the internal thread 26 of the fluid connection 24 and has a longitudinally displaceable valve plate 70 into which a throttle bore 72 is introduced coaxially with respect to the longitudinal axis 60 of the hydraulic accumulator. The valve plate 70 is accommodated in a valve housing 74, which is preferably designed as a tripod and is screwed flush into the fluid connection 24 along the internal thread 26. Since a fluid supply 76 is respectively present between the legs of the valve housing 74, in the position shown for charging the accumulator via the bottom-side inflow 78 in the valve housing 74, for the charging process of the accumulator, the fluid can flow in relatively undisturbed from the hydraulic working circuit via the fluid connection 24 at a predeterminable pressure in the direction of the fluid chamber 16 when the check valve 20 is open. In the opposite direction, i.e. when the accumulator is unloaded, the valve plate 70 is released from its position in the fluid supply 76. Figure 1 7 into a lower closed position in which the valve plate 70 lies against the inner side of the valve housing 74 and the fluid passage is therefore only provided via the throttle opening 72 in the valve plate 70, so that in addition to the throttling measures 22, 46 already described, a throttling of the fluid flow is also achieved via the damping valve 68. More details on the function of the damping valve can be found, for example, in DE 103 37 744 B3.
Claims
1. A piston accumulator, comprising an accumulator housing (10), in which a separating piston (12) is guided in a longitudinally displaceable manner, the separating piston separating two fluid chambers from one another, and the separating piston having a damping piston (18) with a non-return valve (20), the damping piston being able to be moved into a fluid connection (24) in the accumulator housing (10) while forming a throttling gap (22), the throttling gap (22) being a cylindrical annular space formed by adjacent walls (28, 32) of the accumulator housing (10) and the damping piston (18), the non-return valve (20) having a damping piston (18) which is provided through the accumulator. A loaded valve ball (36) which, in its closed position, blocks a fluid path between a fluid connection (24) and a piston fluid chamber (38) between a separating piston (12) and an accumulator housing (10) and releases the fluid path in its open position, and, viewed in the direction of the piston fluid chamber (38), the damping piston (18) transitions into a widened portion with an annular surface (44) while forming a shoulder (42), the annular surface forming an annular gap (46) with the separating piston (12) resting against a component of the accumulator housing, the gap size of the annular gap being greater than the gap size of the throttling gap (22), characterized in that The annular surface (44) is part of an insert body (48) which receives the nonreturn valve (20) and is fixed in a receptacle (50) of the separating piston (12).
2. The piston accumulator according to claim 1, characterized in that: The damping piston (18) is formed by a hollow cylinder which, at least in one of its damping positions, establishes a fluid path between a fluid connection (24) and a non-return valve (20) by means of its hollow cylindrical passage (40).
3. The piston accumulator according to claim 1, characterized in that: The nonreturn valve (20) is designed as a valve cartridge, whose valve housing (54) is screwed into an insert (48) and the valve ball (36) is guided in the valve housing (54) while being continuously loaded by an energy accumulator in the form of a compression spring (34).
4. The piston accumulator according to claim 3, characterized in that: The valve housing (54) has at least one first transverse channel (58) which is directed in the direction of an associated second transverse channel (62) in the insert body (48) in a controllable manner by a valve ball (36) of the nonreturn valve (20).
5. The piston accumulator according to claim 4, characterized in that: The valve housing (54) has a recess (64) on the outer circumference, into which a corresponding first transverse channel (58) of the valve housing (54) opens from one side and into which a correspondingly associated second transverse channel (62) in the insert body (48) opens from the opposite side.
6. The piston accumulator according to claim 4 or 5, characterized in that: The separating piston (12) defines a hollow cavity-like recess as part of the piston fluid chamber (38) on its side facing the fluid connection (24), the hollow cavity-like recess opens into a bevel (66) in the separating piston (12) in the direction of the clamping ring (52), and the hole axis of the corresponding second transverse channel (62) in the insert (48) is aligned with the following wall of the separating piston (12), which wall at least partially defines the recess in the separating piston (12) and the bevel (66) opens into the wall.
7. The piston accumulator according to claim 1 or 2, characterized in that: The axial length of the damping piston (18) is greater than the corresponding height of the piston fluid chamber (38) in the separating piston (12), which is at least partially penetrated by the insert body (48).
8. The piston accumulator according to claim 1, characterized in that The separating piston separates a fluid chamber containing the working gas from another fluid chamber containing the liquid.
9. The piston accumulator according to claim 8, characterized in that The liquid is hydraulic oil.
10. The piston accumulator according to claim 1, characterized in that The annular surface forms the annular gap (46) when the separating piston (12) bears against the housing cover (30).
11. The piston accumulator according to claim 1, characterized in that The insert body is fixed in a receptacle (50) of the separating piston (12) by means of a clamping ring (52) between the insert body (48) and the separating piston (12).
12. The piston accumulator according to claim 5, characterized in that The recess is a recess in the form of a valve annulus.