Piston type energy accumulator

Abstract

The utility model relates to a piston type energy accumulator which is provided with an energy accumulator shell (10) and a separating piston (12) which can be guided in the energy accumulator shell in a longitudinal moving mode. The utility model relates to a separating piston (12) which separates two medium spaces (14, 16), in particular a medium space (14) with a working gas, from another medium space (16) with a liquid, such as hydraulic oil, within the accumulator housing (10), said separating piston (12) having two piston parts (13, 15), the two piston parts are designed as disks having the same outer diameter and are fixedly connected to one another at a distance from one another by means of an elastically flexible piston rod (17), which, starting from an initial state under the action of at least one external force, allows a bending as a whole and returns to the initial state when the respective force is cancelled.

Description

Technical Field

[0001] The utility model relates to a piston type accumulator. Background Art

[0002] This type of piston accumulator is commercially available and is widely used in hydraulic equipment, for example, for energy storage, for emergency operation to cushion mechanical or pressure shocks, for vehicle shock absorption, etc.

[0003] DE 197 01 303 A1 discloses a piston accumulator having a first separating piston that is longitudinally displaceable within the accumulator housing and separates the liquid side of the accumulator from its gas side. A second separating piston is arranged on the liquid side of the accumulator, and the intermediate space arranged between the two separating pistons is filled with a sealing medium that is prestressed under the action of the two separating pistons. The two separating pistons can be moved toward each other by means of an accumulator, typically in the form of a compression spring. To this end, a connecting rod passes through the two separating pistons, and the compression spring is supported at one end on the first separating piston and at the other end on the connecting rod. Thus, a first separating piston of block-like design is guided longitudinally and stably over a relatively long stroke on the inner side of the accumulator housing, which is rigid in this respect, using multiple sealing and guide strips arranged on the outer circumference. However, it is held axially movable on the connecting rod against the preload force of the compression spring, while a second separating piston of disk-like design is guided displaceably along the inner side of the accumulator housing with only one sealing ring and is firmly connected to the connecting rod. Thus, the two separating pistons, on the one hand, are designed as solid blocks and on the other hand as disk-shaped bodies, which are prestressed against each other by the pressure spring acting on the connecting rod, thereby providing a variable two-piece separating piston with a gas barrier in the intermediate space between the separating pistons. This gas barrier prevents small gas molecules from creeping through the otherwise tight sealing system in the form of the sealing rings arranged on the outer circumference of the separating pistons during oil-side pressure relief, which could affect the functional safety of the known piston accumulator in the long term.

[0004] Due to the rigid design of the accumulator housing and the separating piston arrangement, despite the relative displacement of the separating pistons, known piston accumulator arrangements can only be used inadequately in locations that are subject to relevant bending stresses, both from the accumulator housing side and from the separating piston arrangement side. For example, DE 10 2016 003 345 B4 discloses the following bending stresses for a piston accumulator within the scope of a balancing device for compensating for an imbalance of a rotor of a wind power installation, the balancing device comprising at least:

[0005] - a rotor blade having two piston accumulators extending in its longitudinal direction, the separating pistons of which are each preloaded by a compressible medium and which are connected to one another in a medium-conducting manner via a fluid line through an incompressible medium;

[0006] - a control valve which is connected to a corresponding fluid line which establishes a media connection between the two piston accumulators of a pair or can separate them from one another;

[0007] - accelerometer;

[0008] - rotor position sensor; and

[0009] A control system for evaluating the sensor data and actuating at least one piston accumulator pair by actuating control valves.

[0010] The balancing device can be used to balance the corresponding rotor of the wind power installation accordingly during operation, which is usually necessary because imbalances can occur during operation, for example due to dirt deposits on the rotor blades or due to uneven wind inflow, such as when turbulence occurs during wind power operation.

[0011] During operation of a wind turbine, rotor blades often undergo deformations. Kinematic models are used to describe these deformations, for example, based on the Euler-Bernoulli bending beam assumption. The theoretically determinable deformations of the corresponding rotor blades are consistent with actual measured value acquisition, which is preferably based on a combination of photogrammetry and laser scanning measurements. In any case, in practice, this results in rotor blade deformations, typically in the form of reversible bending along the longitudinal axis of the rotor. The piston accumulator, articulated to the rotor blade according to the teaching of DE 10 2016 003 345 B4, must be able to follow these deformations, which result from the continuously changing bending curves caused by the changing wind inflow and the eddies that occur during operation. Piston accumulator solutions, typically constructed from solid steel, are therefore no longer able to follow the time-dependent bending curves of the rotor blades. This often leads to failures at the connection between the piston accumulator and the rotor blade, rendering the imbalance compensation device as a whole unusable.

[0012] Independently of the aforementioned initial situation in wind turbines, piston accumulators can also be subjected to alternating bending stresses that vary under other circumstances, for example when they are subjected to strong vibrations within the operating range of hydraulic systems, as is the case when used in aircraft, rockets, military emergency vehicles, agricultural machinery, etc. Utility Model Content

[0013] Starting from this prior art, the object of the present invention is therefore to further develop a piston accumulator of the aforementioned type in such a way that reliable operation in cooperation with a third component is ensured even in the event of strong bending stresses.

[0014] This object is achieved by a piston accumulator having an accumulator housing and a separating piston guided longitudinally displaceably in the accumulator housing, which separates two media spaces from one another within the accumulator housing, wherein the separating piston has two piston parts, which are designed as disks with the same outer diameter and are fixedly connected to one another at a distance from one another by an elastically flexible piston rod, which can be bent as a whole from an initial state under the action of at least one external force and returns to the initial state when the corresponding force is removed.

[0015] According to the present invention, a separating piston has two piston parts, which are designed as disks with the same outer diameter and are fixedly connected to each other at a distance from each other via an elastically flexible piston rod. The piston rod is allowed to bend as a whole from an initial position under the action of at least one external force and returns to the initial position when the corresponding force is removed. Thus, a piston accumulator is provided that ensures that, even when the accumulator housing is significantly bent, the separating piston with its two piston parts can smoothly follow such bending and return to its initial position again without deformation when the load is released, thereby maintaining normal functionality even in the presence of such bending of the accumulator housing. The fixed coupling of the two piston parts via the elastically flexible piston rod significantly contributes to achieving the linear elastic behavior (Hooke's law) for the multi-part separating piston by means of this coupling. Furthermore, the elastically flexible coupling of the piston rod prevents the disk-shaped piston parts from tilting relative to each other within the accumulator housing, thereby compromising smooth operation.

[0016] According to a development of the present invention, the two medium spaces include a first medium space containing working gas and a second medium space containing liquid.

[0017] According to a development of the present invention, the liquid is hydraulic oil.

[0018] According to an extension of the present invention, the two piston components include a first piston component and a second piston component, the first piston component facing the first medium space has a first guide band on the outer peripheral side, and the second piston component facing the second medium space has a second guide band and an annular seal, and the second guide band and the annular seal are arranged adjacent to the first guide band of the first piston component on the outer periphery of the second piston component.

[0019] According to a development of the present invention, the two piston components define an annular space therebetween, which contains the medium of the first medium space.

[0020] According to a further development of the present invention, the distance between the two piston components is greater than 1 / 3 of the diameter of the corresponding piston component and smaller than the diameter.

[0021] According to a further development of the present invention, the distance between the first guide strip and the second guide strip is greater than 1 / 3 of the diameter of the corresponding piston component and smaller than the diameter.

[0022] According to a development of the invention, the disk thickness of the first piston part having the first guide strip is smaller than the disk thickness of the second piston part having the second guide strip and the annular seal.

[0023] According to a development of the invention, the piston rod transitions smoothly with two mutually opposite shoulders into the free end faces of the two piston parts that face toward each other.

[0024] According to a development of the invention, the piston rods extend through the corresponding piston components with their end regions facing away from one another and are fixed along the end regions to the associated piston components via threaded sections by means of lock nuts.

[0025] According to a development of the invention, the disks of the two piston parts are provided with an annular recess.

[0026] According to a development of the invention, the annular recess extends concentrically with a central recess, through which respectively assignable end regions of the piston rod together with the union nut pass.

[0027] According to a development of the invention, the first guide strip and the second guide strip are of identical design and, viewed in the axial direction, have a greater extension than the annular seal.

[0028] According to a further development of the present invention, the annular seal is formed of an elastomer.

[0029] According to another advantageous embodiment of the piston accumulator of the present invention, the flexibility of the separating piston and its two piston parts, through the elastically flexible piston rod arranged therebetween, allows the piston rod to follow the resulting bending curve with its longitudinal axis without any constraint, even when the accumulator housing is bent along the central bending axis. This also applies to the return situation when the bending line transitions back to the straight central axis. Therefore, this does not correspond to the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The piston accumulator according to the present invention will be explained in detail below with reference to an exemplary embodiment according to the accompanying drawings.

[0031] Here, the diagram is shown in principle and not to scale:

[0032] Figure 1 The edge-side end region of an accumulator housing, which is designed as a lining composite in a sandwich structure, is shown in longitudinal section;

[0033] Figure 2 Show the basis Figure 1 An end view of a housing cover for an accumulator housing;

[0034] Figure 3 Shown in Figure 1 An enlarged portion of the end section of the accumulator housing indicated by X;

[0035] Figure 4 The schematic diagram shows the bending force introduced in the direction of the arrow. Figure 1 Possible bending curves of the accumulator housing;

[0036] Figure 5 and Figure 6 Shown in side view and end view according to Figure 1 a separating piston for an accumulator housing;

[0037] Figure 7 Shown in Figure 5 The separating piston shown in Figure 1 used in the accumulator housing; and

[0038] Figure 8 Show the basis Figure 7 Use of a piston accumulator of the embodiment of the invention in a wind turbine having three circumferential rotor blades. DETAILED DESCRIPTION

[0039] Figure 1 The accumulator housing 10 of the piston accumulator is shown in longitudinal section, and Figure 7The accumulator housing 10 is shown, which has a separating piston 12 arranged therein so as to be longitudinally displaceable, which separates two media spaces 14, 16 from one another within the accumulator housing 10 and which is arranged in a longitudinally displaceable manner. Figure 5 and Figure 6 Here, the medium space 14 can be used to accommodate an operating gas, for example in the form of nitrogen, and the other medium space 16 can be used to accommodate an operating fluid, for example hydraulic oil. Since the accumulator housing 10 can have a correspondingly large overall length, for example in the order of 2 meters, Figure 1 and Figure 7 The accumulator housing 10 is shown only in the region of its end faces; however, in the middle region, the accumulator housing 10 is also designed in the same manner as the edge-side end regions, which relates to the lining structure of the accumulator housing 10. Accordingly, the accumulator housing 10 is constructed in a sandwich structure from individual, partially different layers 18, 20, 22 and 24 in such a way that it is elastically deformed under the action of at least one external force F, as in the example of FIG. Figure 1 and Figure 7 Starting from the initial state given in Figure 4 The simplified illustration of FIG. 1 shows the bending of the accumulator housing 10 as a whole, and when the corresponding force F is removed, the accumulator housing 10 elastically returns to the initial state. In this respect, the sandwich construction method thus allows linear elastic properties of the accumulator housing 10 .

[0040] In the context of the sandwich construction, the innermost layer 18 of the housing 10 is airtight and the layers 20, 22 and 24 adjacent to the outside are formed from fiber windings. Such a layer composite is composed in particular of Figure 3 It is shown that Figure 1 The innermost layer 18 is designed as a thin-walled steel tube, which is preferably produced in one piece by means of flow pressure and forms a smooth running surface 26 for the separating piston 12 on the inner circumference (according to the Figure 7). The steel lining 18 extends over the entire length of the accumulator housing 10, up to its free end. The respective fiber winding for the accumulator housing 10 has a winding direction that differs from the respective preceding fiber winding in the winding sequence. The respective fiber winding preferably consists of a carbon fiber material, and the fiber winding of the layer 20 is wound onto the steel layer 18 in the circumferential direction, thus having a winding direction that is less than 90° relative to the longitudinal direction 28 of the accumulator housing 10. In contrast, the adjacent layer 22 can deviate from the aforementioned 90° winding direction by 0° to 45°; however, it is also possible to attach such a layer 22 to the winding 20 as parallel as possible to the longitudinal direction 28 of the accumulator housing 10. Other winding directions and the application of other layers are also possible, depending on the respective application and the required rigidity of the entire accumulator housing 10. The outermost layer 24 in turn consists of a fiber winding in the same direction as the wound layer 20 , ie in a radial winding direction at 90° to the longitudinal direction 28 .

[0041] As especially by Figure 3As further shown, an annular connecting component 30 is provided at each end of the accumulator housing 10. These connecting components are constructed as identical parts. The annular or cylindrical connecting component 30 is penetrated by the steel lining 18 on its inner circumference and is open at the end at the free end of the connecting component 30. Each connecting component 30 has an annular receiving groove 32 on its outer circumference for accommodating the fiber layers of the two outermost windings 22 and 24. The receiving groove 32 is bounded on one side by a connecting flange 34 and on its inner side by a securing ramp 36. Both the connecting flange 34 and the securing ramp 36 have obliquely extending contact surfaces 38 and 40 on their adjacent sides. These contact surfaces form a cone in an imaginary extension toward the groove bottom 42. The securing ramp 36 is overlapped by the third layer 22, which directly contacts the groove bottom 42 of the receiving groove 32. Here, the third layer 22 terminates sharply at its free end and ends at the bottom of an obliquely extending contact surface 38. The sharply ending end of the third layer 22 defines an obliquely extending wall portion 44 of the third layer 22, which, together with the obliquely extending contact surface 38 of the connecting element 30, forms another V-shaped engagement groove 46, also designed as an annular groove, for engaging the free end of the outer layer 24. Conversely, the second layer 20, adjacent to the steel layer 18 in the wound composite, rests against a ramp portion 48 of the securing ramp 36, which, in the region with the smaller inclination angle, abuts the innermost layer 18 on the bottom side. This allows for a secure layer or lining composite structure of the individual layers 18, 20, 22, and 24 in their free end regions via the corresponding connecting element 30 with the connecting flange 34 and securing ramp 36 within the sandwich construction.

[0042] At the point of the transition between the abutment surface 40 extending steeply and the ramped surface extending relatively flat thereto (including the reference ramp element 48 ), the fixing ramp 36 is arranged according to Figure 3 The illustration has a substantially horizontally extending circumferential surface or engagement surface 50, which is used to pass through individual, preferably metallic, retaining pins 52, which are evenly distributed around the accumulator housing 10 at discrete distances from one another in the radial direction and securely connect the layer composite structure consisting of the individual layers 18, 20, 22 and 24 to the connecting part 30 and thus ensure a reliable layer composite structure.

[0043] Pin recesses 54 are provided on the free end faces of the respective connecting flanges 34 of the connecting components 30 and are evenly distributed around the outer circumference of the connecting flanges 34. These pin recesses 54 allow the respective cover components 56 to be pinned to the associated connecting components 30, with such a cover component 56 being present at each free end of the accumulator housing 10. The associated pins (not shown in detail) are attached to the cover components 56 along an annular surface 58 provided for this purpose, the imaginary inner course of which is indicated by a dashed line 60. Furthermore, such annular surface 58, on its inner side facing the accumulator housing 10, is used for applying adhesive in order to establish a media-tight connection between the two media spaces 14, 16 and the surrounding environment. Furthermore, within the scope of an embodiment (not shown in detail), it is possible to connect the respective cover components 56 to the accumulator housing 10 in a media-tight and pressure-resistant manner via a fiber winding. In the middle region of each cover part 56 there is a connecting opening 62 which can be sealed with the medium space 14 on the gas side of the accumulator housing 10 and remains open on the liquid side in order to connect the other medium space 16 to a conventional hydraulic circuit (not shown). In order to separate the two medium spaces 14, 16, i.e. the gas side and the liquid side, in a medium-tight manner, a connecting opening 62 is provided according to the accompanying Figure 7 The separating piston 12 is inserted into the accumulator housing 10 in a longitudinally movable manner. Figure 5 and Figure 6 Detailed description is given in FIG. Figure 6 Show the basis Figure 5 The separating piston 12 is shown in a side view from the right. The separating piston 12 has two piston parts 13, 15, which are designed as disks with the same outer diameter and are fixedly connected to each other at a distance from each other via an elastically flexible piston rod 17. The piston rod 17 can be bent as a whole from an initial position under the action of at least one external force F and returns to the initial position when the corresponding force F is removed. In this way, the double-disk piston arrangement of the separating piston 12 appropriately follows the curvature of the accumulator housing 10, as shown in the example. Figure 4 As can be seen in FIG. Like the two piston parts 13 , 15 , the piston rod 17 is made of a suitable metallic material, wherein the piston rod 17 is preferably designed to be more flexurally elastic than the disks 13 , 15 . In particular, the piston rod 17 prevents the relatively thin disks for the two piston parts 13 , 15 from tilting along the running surface 26 in the accumulator housing 10 within the scope of the guide, thereby preventing the movement process for separating the piston 12 .

[0044] One piston part 13 facing one of the media spaces 14 has a guide strip 19 on the outer peripheral side, and the other piston part 15 facing the other media space 16 has another guide strip 21 and an annular seal 23 made of a conventional elastomer material. The two annular guide strips 19, 21 are designed as identical parts and are made of a material with good sliding properties, which is preferably resistant to temperature changes, such as PTFE material. Not only the guide strips 19, 21 but also the annular seal 23 are introduced into corresponding annular receiving grooves in the corresponding piston parts 13, 15 and slide along the inner peripheral side of the accumulator housing 10 in the form of a working surface 26. In this regard, according to Figure 5 In the illustration, an annular seal 23 is arranged on the other piston part 15 between the two guide strips 19, 21. Due to the disk-shaped arrangement of the two piston parts 13, 15, an annular space 25 is formed between them, which contains the medium of one of the media spaces 14, particularly in the form of working gas. To avoid the aforementioned tilting of the disk-shaped piston parts 13, 15 and to ensure that the separating piston 12 as a whole can follow the curved path of the accumulator housing 10, which is subject to bending stress, the distance between the two disk-shaped piston parts 13, 15 is greater than one-third of the diameter of the respective piston part 13, 15, and in any case less than this diameter. Furthermore, for a reliable displacement process, the disk thickness of the piston part 13 with the guide strip 19 is selected to be smaller than the disk thickness of the other piston part 15 with the additional guide strip 21 and sealing ring 23. Furthermore, for trouble-free operation, it is provided that the piston rod 17 transitions smoothly with its two mutually opposite shoulders 27 into the free end sides 29, 31 of the two piston parts 13 or 15 that face each other. Accordingly, the piston rod 17 passes through the respective piston part 13, 15 with its end regions facing away from each other and is fixed along said end regions on the threaded section 33 by means of a conventional lock nut 35 to the associated piston part 13, 15. Figure 6 is shown in the diagram.

[0045] If further Figure 5 、 Figure 6 and Figure 7It can be seen that the disks of the two piston parts 13, 15 are provided with annular recesses 37, which serve to save weight and also to increase the elasticity of the disks 13, 15. The recesses 37 are essentially identical on the facing ends of the two piston parts 13, 15 and are arranged concentrically with respect to a central recess 39, which accommodates the corresponding threaded section 33 of the piston rod 17 and the lock nut 35. Furthermore, in a concentric arrangement with these recesses 37, an annular recess 37 is present on the inner end wall of the piston part 15, widening both on the outer circumference and on the inner circumference. This elastically designed separating piston 12 can also be used with a "standard" accumulator housing 10; similarly, the accumulator housing 10 of the type described can be used with a "conventional" separating piston. Instead of the lock nut 35, any other suitable connection, such as screwing, gluing, or using a fixing pin, can also be used.

[0046] Figure 4 The accumulator housing 10 is now shown supported on two bearing blocks 64 and a pressure F is applied centrally from above at the insertion point 66 so that the accumulator housing 10 is as shown in FIG. Figure 4 Bend as shown in . Figure 4 In FIG. 5 , the accumulator housing 10 is shown in an idealized form, in particular without the two closure cover parts 56. If the force F is removed, the accumulator or the accumulator housing 10 returns to its original position according to FIG. Figure 1 and Figure 7 It is understood that when the accumulator housing 10 is fixed at the introduction position 66 and a force is applied from below via the support seat 64, the same Figure 4 A similar curvature is shown in .

[0047] If the piston accumulator is installed in the framework of a balancing device for compensating for imbalances of the rotor of a wind power plant, as in Figure 8 As shown by way of example in FIG, the fixing then takes place along the two bearing seats 64 on one of the two blade sides of the respective rotor blade 68. Figure 8 In FIG, a partially shown tower of a wind power plant is designated by 70. As is customary in wind power plants, a machine room 72, also designated in technical terms as a "nacelle," is arranged at the upper end of the tower 70 so as to be rotatable about the vertical tower axis, rotatable two to three times forward and backward. Figure 8 The simplified illustration of the rotor hub for the three rotor blades 68 of the three-blade rotor, which is rotatably mounted on the machine room 72, cannot be seen. A piston accumulator pair is provided in each rotor blade 68, which has an inner piston accumulator 74 and an outer piston accumulator 76. In this case, the respective piston accumulators 74, 76 are arranged according to the principle as in Figure 7 , the piston accumulators 74 and 76 are shown as being configured with corresponding end-side closure components, such as corresponding cover components 56. Here, the corresponding piston accumulators 74 and 76 are fixed to the corresponding rotor blades 68 via the associated bearing blocks 64.

[0048] The respective inner piston accumulator 74 is arranged in the region of the blade root adjacent to the rotor hub, while the outer piston accumulator 76 is offset relative thereto by a distance extending in the longitudinal direction of the respective rotor blade 68 in the direction of the respective blade tip. It is preferably provided that, due to the smaller installation space available in the vicinity of the blade tip within the respective rotor blade 68, the outer piston accumulator 76 is dimensioned more slenderly than the inner piston accumulator 74 of the pair.

[0049] In the inner piston accumulator 74, the medium space or working space 14 (which carries a compressible pressure medium, such as a working gas, preferably in the form of nitrogen) faces the blade root, while in the outer piston accumulator 76, the working space 14 carries the compressible medium toward the blade tip. If necessary, the medium space 14 of the inner piston accumulator 74 can also carry ambient air and remain pressureless. In the respective other medium spaces 16 of the piston accumulators 74 and 76 facing each other within the rotor blade 68, an incompressible medium, such as a hydraulic fluid, is provided as a mass that can be moved within the rotor blade 68 to compensate for imbalances. These fluid-carrying medium spaces 16 facing each other are interconnected via fluid lines 78, for example, in the form of pipes or tubes. In the respective fluid lines 78, adjacent to each inner piston accumulator 74, a control valve 80, for example, in the form of an electromagnetically actuated switching valve, is arranged. This control valve can be centrally controlled by a control system 82. In order to transmit the value of the transverse acceleration acting on the support structure of the wind power installation transversely to the rotor axis to the control system 82, an acceleration sensor 84 is arranged in the tower top or in the nacelle 72 and is connected to the control system 82 via corresponding measurement signal lines. In addition, a rotor position sensor 86 is provided, which detects the position of the rotor blades 68 on the rotor shaft in the form of a rotor speed sensor or rotor rotational position sensor and transmits it to the control system 82 via another measurement signal line.

[0050] To perform the imbalance compensation process using the balancing device, the wind turbine is brought into an initial state by increasing the rotor speed by motor drive to a speed at which, when the control valve 80 is opened, the hydraulic fluid in the media spaces 16 of the piston accumulators 74, 76 and in the fluid line 78 located therebetween is displaced outwards towards the blade tips under the action of centrifugal force, thereby compressing the working gas in the corresponding media space 14 of the outer piston accumulator 76, thereby loading it. To detect the presence of an imbalance, the wind turbine must be operated at a critical speed, and when an imbalance is present, operation at this speed results in transverse tower vibrations and, therefore, in the generation of acceleration signals from the acceleration sensor 84. The rotor rotational position sensor on the rotor shaft determines which of the rotor blades 68 has a deviating moment of inertia, which determines the exact position of the rotor blades 68 at any given moment. From the instantaneous value of the transverse acceleration of the rotor position, the control system 82 determines which rotor blades 68 have different moments of inertia and provides control signals for the control valves 80. These control valves partially discharge the charged piston accumulator 76 in question, thereby displacing the mass of the incompressible hydraulic fluid so that the transverse acceleration is no longer measured. The rotor is thus balanced overall.

[0051] It is understood that during operation of the rotor blades 68, deformations may occur due to wind influences (also within the context of the occurrence of turbulence) due to bending forces, in particular bending of the corresponding rotor blades 68 in their longitudinal orientation. Due to the above-described piston accumulator solution, using a flexurally elastic accumulator housing 10 and / or a flexurally elastic separating piston 12, corresponding bending deformations of the rotor blades 68 in all directions can be absorbed, wherein the piston accumulator pairs 74, 76 can also perform a functionally reliable mass balance to compensate for imbalances of the rotor blades 68 in the presence of such bending.

Claims

1. A piston accumulator comprising an accumulator housing (10) and a separating piston (12) guided longitudinally displaceably in the accumulator housing, the separating piston separating two media spaces from one another within the accumulator housing (10), characterized in that: The separating piston (12) has two piston parts, which are designed as disks with the same outer diameter and are fixedly connected to each other at a certain distance from each other by an elastically flexible piston rod (17), which allows bending as a whole from an initial state under the action of at least one external force (F) and returns to the initial state when the corresponding force (F) is removed.

2. The piston accumulator according to claim 1, characterized in that The two medium spaces include a first medium space (14) containing a working gas and a second medium space (16) containing a liquid.

3. The piston accumulator according to claim 2, characterized in that The liquid is hydraulic oil.

4. The piston accumulator according to claim 2 or 3, characterized in that: The two piston components include a first piston component and a second piston component, the first piston component (13) facing the first medium space (14) having a first guide band (19) on the outer circumference side, and the second piston component (15) facing the second medium space (16) having a second guide band (21) and an annular seal (23), the second guide band and the annular seal being arranged on the outer circumference of the second piston component (15) adjacent to the first guide band (19) of the first piston component (13).

5. The piston accumulator according to claim 2 or 3, characterized in that: The two piston parts define an annular space (25) therebetween, which contains the medium of the first medium space (14).

6. The piston accumulator according to any one of claims 1 to 3, characterized in that The distance between the two piston parts is greater than 1 / 3 of the diameter of the corresponding piston part and smaller than the diameter.

7. The piston accumulator according to claim 4, characterized in that The first guide strip and the second guide strip are located at a distance from each other that is greater than ⅓ of the diameter of the corresponding piston component and smaller than the diameter.

8. The piston accumulator according to claim 4, characterized in that The disk thickness of the first piston part (13) with the first guide band (19) is smaller than the disk thickness of the second piston part with the second guide band (21) and the annular seal (23).

9. The piston accumulator according to any one of claims 1 to 3, characterized in that The piston rod (17) transitions smoothly with two mutually opposite shoulders (27) into the free end faces (29, 31) of the two piston parts that face toward each other.

10. The piston accumulator according to any one of claims 1 to 3, characterized in that The piston rod (17) extends through the corresponding piston component with its end regions facing away from one another and is fixed along the end region to the associated piston component via a threaded section (33) by means of a lock nut (35).

11. The piston accumulator according to claim 10, characterized in that The disks of the two piston parts are provided with an annular recess (37).

12. The piston accumulator according to claim 11, characterized in that The annular recess (37) extends concentrically with a central recess (39), which is penetrated by respectively assignable end regions of the piston rod (17) together with the union nut (35).

13. The piston accumulator according to claim 4, characterized in that The first and second guide strips are identically designed and, viewed in the axial direction, have a greater extension than the annular seal (23).

14. The piston accumulator according to claim 13, characterized in that The annular seal (23) is made of elastomer.

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