Flywheel energy storage device

Abstract

The utility model provides a flywheel energy storage device. The flywheel energy storage device comprises a protective shell, a stator, a rotor, a magnetic bearing, a lower supporting mechanism and a pressing mechanism. In order to prevent the rotor from skewing and colliding due to vibration or shaking in the moving period, during transportation, the lower supporting mechanism drives the rotor to move downwards till the rotor makes contact with the supporting part, then the pressing mechanism is adjusted to enable the jacking part to press the rotor downwards, at the moment, the rotor is pressed and fixed by the jacking part and the supporting part, and transportation is convenient. And after the magnetic bearing is transported to a mounting station, the pressing mechanism is adjusted to ascend, and then the lower supporting mechanism is adjusted to drive the rotor to ascend and restore to the original position, so that the relative positions of the rotor and the magnetic bearing are restored. According to the flywheel energy storage device, the lower supporting mechanism and the pressing mechanism which can vertically move are arranged, and the supporting part used for supporting the rotor is arranged on the inner wall of the protective shell, so that the rotor can be switched between a transportation posture and a working posture, the flywheel energy storage device can be normally transported, field assembly is not needed, and the flywheel energy storage device is more convenient to use.

Description

Technical Field

[0001] The utility model belongs to the technical field of flywheel energy storage, and particularly relates to a flywheel energy storage device. Background Art

[0002] A flywheel energy storage device is an energy storage equipment, and its working principle is to realize the storage and release of electric energy through the acceleration and deceleration of a rotor. When the electric energy is sufficient, the electric energy is used to drive the flywheel to rotate at a high speed, and the electric energy is converted into mechanical energy for storage. When the system needs it, the flywheel decelerates, and the motor operates as a generator, which can convert the kinetic energy of the flywheel into electric energy for users. At present, the flywheel energy storage technology has been applied on a large scale in the fields such as kinetic energy recovery of rail transit and power grid frequency modulation.

[0003] The rotor of the flywheel is an important component of the flywheel energy storage device. In order to enable the rotor to accumulate a large enough kinetic energy, the size and weight of the rotor are generally designed to be relatively large. In order to improve the power density and energy density, the flywheel needs to rotate at a high speed. The shafting of the flywheel generally adopts a vertical installation structure. In order to reduce the frictional loss, the shell of the flywheel energy storage device is subjected to vacuum pumping treatment, and magnetic bearings are widely used as the bearing type.

[0004] Since the flywheel energy storage device has high requirements for the manufacturing and assembly accuracy of components, and the flywheel energy storage device needs to be transported to a designated site after production and manufacturing, the skew or collision of the machine body during transportation will affect the product accuracy. In the rotor system using passive magnetic bearings, the vibration and tilt during transportation will directly affect the control stability of the passive magnetic bearings for the rotor. To solve this problem, in the prior art, the flywheel energy storage device adopts an on-site assembly method, that is, each component is first transported to the site, and then assembled on-site by technical personnel, and operations such as sealing and vacuum pumping are carried out. This method is time-consuming and laborious, and requires on-site installation equipment, resulting in high costs. Summary of the Utility Model

[0005] The utility model provides a flywheel energy storage device, aiming at solving the problem that the flywheel energy storage products in the prior art are inconvenient to transport and can only meet the assembly accuracy requirements through on-site assembly.

[0006] To achieve the above object, the technical solution adopted by the utility model is: to provide a flywheel energy storage device, including:

[0007] A protective shell, which forms an accommodation cavity inside, and a support part is provided on the side wall of the protective shell;

[0008] A stator, which is arranged in the accommodation cavity along the vertical direction;

[0009] The rotor shaft group includes a rotor, a magnetic bearing, and a lower support mechanism respectively accommodated in the accommodation cavity. The rotor is coaxially arranged with the stator and is located above the support part. The magnetic bearing is arranged above the rotor and is coaxially arranged with the rotor. The lower support mechanism is arranged below the rotor, and the lower support mechanism can move in the vertical direction; and

[0010] A pressing mechanism is arranged on the protective housing and is located above the rotor. The pressing mechanism has a pressing part that can move vertically;

[0011] The rotor has a transportation posture and a working posture. When in the transportation posture, the bottom of the rotor abuts against the support part, and the pressing part abuts against the upper part of the rotor; when in the working posture, there is a first gap between the rotor and the support part, and there is a second gap between the rotor and the pressing part.

[0012] In a possible implementation manner, the protective housing includes:

[0013] A cylinder liner, which is a cylindrical member. The cylinder liner has an inner cavity that penetrates in the vertical direction. The support part is arranged in the inner cavity, and the lower support mechanism is arranged at the lower part of the cylinder liner; and

[0014] A cylinder head is arranged above the cylinder liner. The cylinder head and the cylinder liner enclose to form the accommodation cavity. The stator, the pressing mechanism, and the magnetic bearing are respectively connected to the cylinder head.

[0015] In a possible implementation manner, the pressing mechanism includes:

[0016] A transportation pressing plate is arranged in the accommodation cavity and is located above the rotor. The transportation pressing plate forms the pressing part; and

[0017] A pressing rod is arranged on the protective housing and is connected to the transportation pressing plate. The pressing rod can move vertically relative to the protective housing.

[0018] In a possible implementation manner, an adjustment hole is opened at the top of the protective housing. The pressing rod is in threaded cooperation with the adjustment hole. One end of the pressing rod accommodated in the accommodation cavity abuts against the transportation pressing plate;

[0019] The pressing mechanism further includes an elastic connecting member. The elastic connecting member is connected between the transportation pressing plate and the protective housing and is configured with an elastic pre-tightening force to move the transportation pressing plate upward.

[0020] In a possible implementation manner, the elastic connecting member is a spring.

[0021] In a possible implementation, the transport pressing plate is annular, there are multiple pressing rods, the multiple pressing rods are arranged at intervals along the circumference of the transport pressing plate, and the elastic connectors and the adjusting holes correspond to the pressing rods one by one.

[0022] In a possible implementation, the lower support mechanism includes:

[0023] A hydrodynamic bearing, disposed in the accommodation cavity and connected to the lower part of the rotor; and

[0024] A damper, disposed in the accommodation cavity and connected below the hydrodynamic bearing, and the damper can move vertically relative to the protective housing.

[0025] In a possible implementation, the damper includes:

[0026] A damper housing, disposed at the lower part of the protective housing and sealingly fitted with the inner wall of the accommodation cavity, the damper housing has a sealing cavity penetrating in the vertical direction, and an installation hole communicating with the sealing cavity is opened at the bottom of the damper housing; and

[0027] A damper body, including a sealing part and an installation part, the sealing part is sealingly fitted with the sealing cavity, the hydrodynamic bearing is disposed above the sealing part, and the installation part is connected below the sealing part and is in threaded fit with the installation hole.

[0028] In a possible implementation, an annular sealing groove is formed on the outer peripheral surface of the sealing part, and a sealing ring is disposed in the sealing groove.

[0029] In a possible implementation, the hydrodynamic bearing is a spiral groove hydrodynamic bearing.

[0030] Compared with the prior art, the beneficial effects of the flywheel energy storage device provided by the present utility model are:

[0031] The flywheel energy storage device provided by the present utility model includes a protective housing, a stator, a rotor, a magnetic bearing, a lower support mechanism, and a pressing mechanism. The lower support mechanism is located below the rotor, capable of supporting the rotor and moving vertically. The pressing mechanism is located above the rotor and has a pressing portion capable of moving vertically. During the normal use of the flywheel energy storage device, the rotor, the protective housing, and the pressing mechanism are all not working. When transportation is required, in order to prevent the rotor from tilting or colliding due to vibration or shaking during movement, the lower support mechanism can first be used to drive the rotor to move downward until the bottom surface of the rotor contacts the support portion, and then the pressing mechanism is adjusted to make the pressing portion press the rotor downward. At this time, the rotor is tightly fixed by the pressing portion and the support portion, which is convenient for transportation. When transported to the installation station, the pressing mechanism is adjusted to rise, and then the lower support mechanism is adjusted to drive the rotor to rise and return to the original position, so as to restore the relative position of the rotor and the magnetic bearing.

[0032] By providing a vertically movable lower support mechanism and a pressing mechanism, and arranging a support portion for supporting the rotor on the inner wall of the protective housing, the present utility model enables the rotor to switch between a transportation posture and a working posture, making the flywheel energy storage device capable of normal transportation without on-site assembly, which is more convenient. Description of the Drawings

[0033] Figure 1 is an internal cross-sectional view of the flywheel energy storage device provided by one embodiment of the present utility model;

[0034] Figure 2 is Figure 1 a partial enlarged view of part A in

[0035] Figure 3 is a structural schematic diagram of the flywheel energy storage device provided by one embodiment of the present utility model;

[0036] Figure 4 is an exploded assembly view of the flywheel energy storage device provided by one embodiment of the present utility model.

[0037] Description of the Reference Numerals:

[0038] 1. Flywheel energy storage device;

[0039] 10. Protective housing; 11. Cylinder sleeve; 111. Support portion; 12. Cylinder head;

[0040] 20. Stator;

[0041] 30. Rotor shaft group; 31. Rotor; 32. Magnetic bearing; 33. Lower support mechanism; 331. Hydrodynamic bearing; 332. Damper; 3321. Damper housing; 3322. Damper body; 3323. Sealing ring;

[0042] 40. Compression mechanism; 41. Transportation pressure plate; 42. Pressure rod; 43. Elastic connection member Specific implementation manners

[0043] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present utility model clearer and more understandable, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0044] It should be noted that when an element is referred to as being "fixed to", "fixed", "fixedly provided on" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected to", "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. When an element is referred to as being "provided on", "provided in" another element, it can be directly on the other element or there may also be an intermediate element. "Multiple" means two or more quantities. "At least one" means one or more quantities. "Several" means one or more quantities.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present utility model belongs.

[0046] Please refer to Figures 1 to 4 simultaneously, and the flywheel energy storage device 1 provided by the embodiment of the present utility model will be described below.

[0047] Please refer to Figure 1 、 Figure 2 and Figure 4 simultaneously. The embodiment of the present utility model provides a flywheel energy storage device 1, including a protective housing 10, a stator 20, a rotor shaft group 30 and a compression mechanism 40. An accommodation cavity is formed inside the protective housing 10, and a support portion 111 is provided on the side wall of the protective housing 10; the stator 20 is arranged in the accommodation cavity along the vertical direction; the rotor shaft group 30 includes a rotor 31, a magnetic bearing 32 and a lower support mechanism 33 respectively accommodated in the accommodation cavity. The rotor 31 is coaxially arranged with the stator 20 and is located above the support portion 111. The magnetic bearing 32 is arranged above the rotor 31 and is coaxially arranged with the rotor 31. The lower support mechanism 33 is arranged below the rotor 31, and the lower support mechanism 33 can move along the vertical direction; the compression mechanism 40 is arranged on the protective housing 10 and is located above the rotor 31. The compression mechanism 40 has a pressing portion that can move vertically; the rotor 31 has a transportation posture and a working posture. When in the transportation posture, the bottom of the rotor 31 abuts against the support portion 111, and the pressing portion abuts against the upper part of the rotor 31; when in the working posture, there is a first gap between the rotor 31 and the support portion 111, and there is a second gap between the rotor 31 and the pressing portion.

[0048] Compared with the prior art, the beneficial effects of the flywheel energy storage device 1 provided by the embodiment of the present utility model are as follows:

[0049] The flywheel energy storage device 1 provided by the embodiment of the present utility model includes a protective housing 10, a stator 20, a rotor 31, magnetic bearings 32, a lower support mechanism 33, and a pressing mechanism 40. The lower support mechanism 33 is located below the rotor 31, can support the rotor 31, and can move in the vertical direction. The pressing mechanism 40 is located above the rotor 31 and has a pressing part that can move vertically. During the normal use of the flywheel energy storage device 1, the rotor 31, the protective housing 10, and the pressing mechanism 40 do not work. When transportation is required, in order to prevent the rotor 31 from tilting or colliding due to vibration or shaking during movement, the lower support mechanism 33 can first drive the rotor 31 to move downward until the bottom surface of the rotor 31 contacts the support part 111, and then the pressing mechanism 40 is adjusted to make the pressing part press the rotor 31 downward. At this time, the rotor 31 is pressed and fixed by the pressing part and the support part 111, which is convenient for transportation. After being transported to the installation station, the pressing mechanism 40 is adjusted to rise, and then the lower support mechanism 33 is adjusted to drive the rotor 31 to rise and return to the original position, so as to restore the relative position of the rotor 31 and the magnetic bearings 32.

[0050] In the embodiment of the present utility model, the protective housing 10 is a hollow housing member with an accommodation cavity inside for accommodating various components and playing a protective role. The inner wall of the accommodation cavity is provided with a support part 111. The support part 111 can be an annular boss or a plurality of circumferentially arranged protrusions, as long as it can support the rotor 31 during transportation. The stator 20 is arranged in the accommodation cavity, and the stator 20 is coaxially arranged with the rotor 31. Optionally, the stator 20 can be located inside the rotor 31 (i.e., the outer rotor setting form) or outside the rotor 31 (i.e., the inner rotor arrangement form).

[0051] The rotor shaft group 30 includes a rotor 31, magnetic bearings 32, and a lower support mechanism 33. The magnetic bearings 32 can specifically be passive magnetic bearings 32 or other types of magnetic bearings 32. The lower support mechanism 33 can be a hydrodynamic bearing 331 and a damper 332. Among them, the magnetic bearings 32, the hydrodynamic bearing 331, and the damper 332 can all directly select existing products on the market, and there is no limit to their specific specifications and models.

[0052] The passive magnetic bearing 32 and the rotor 31 are respectively provided with circumferential NS-level magnetism. During use, the force of the rotor 31 on the hydrodynamic bearing 331 must be strictly controlled, and it is required that the up and down fluctuation of this force does not exceed 30 N. Under such control requirements for the downforce accuracy, the continuous and stable operation of the hydrodynamic bearing 331 can be achieved. To achieve this, the axial relative position of the magnetic bearing 32 and the rotor 31 must be strictly controlled. The axial stiffness of the flywheel energy storage device 1 can reach about 700 N / mm, because the height of each magnetic pole is relatively low. Once the rotor 31 generates an axial displacement due to vibration or inclination during transportation, and the axial displacement exceeds a certain value, the downforce of the magnetic bearing 32 on the rotor 31 will become a lifting force. If this lifting force exceeds the weight of the rotor 31 itself, it will cause the rotor 31 to rise, and at this stiffness, the acceleration of the rotor 31 rising will be very large, causing damage to the rotor 31 and its body.

[0053] In the embodiment of the present utility model, by providing a vertically movable lower support mechanism 33 and a pressing mechanism 40, and arranging a support portion 111 for supporting the rotor 31 on the inner wall of the protective housing 10, the rotor 31 can be switched between the transportation posture and the working posture, enabling the flywheel energy storage device 1 to be transported normally without on-site assembly, which is more convenient.

[0054] Please refer to Figure 1 、 Figure 3 and Figure 4 In some possible embodiments, the protective housing 10 includes a cylinder liner 11 and a cylinder head 12. The cylinder liner 11 is a cylindrical member. The cylinder liner 11 has an inner cavity penetrating in the vertical direction. The support portion 111 is arranged in the inner cavity, and the lower support mechanism 33 is arranged at the lower part of the cylinder liner 11; the cylinder head 12 is arranged above the cylinder liner 11, and the cylinder head 12 and the cylinder liner 11 enclose a containing cavity. The stator 20, the pressing mechanism 40 and the magnetic bearing 32 are respectively connected to the cylinder head 12. In this embodiment, the cylinder liner 11 is a cylindrical member, the cylinder head 12 is covered on the top end of the cylinder liner 11, enclosing a containing cavity with the cylinder liner 11, and the pressing mechanism 40 is arranged at the bottom of the cylinder liner 11.

[0055] Please refer to Figure 1 、 Figure 2 and Figure 4 In some possible embodiments, the pressing mechanism 40 includes a transportation pressing plate 41 and a pressing rod 42. The transportation pressing plate 41 is arranged in the containing cavity and is located above the rotor 31 to form a pressing portion; the pressing rod 42 is arranged on the protective housing 10 and is connected to the transportation pressing plate 41. The pressing rod 42 can move vertically relative to the protective housing 10.

[0056] In this embodiment, the transportation pressing plate 41 can be a circular pressing plate. The pressing rod 42 is connected to the transportation pressing plate 41 and can drive the transportation pressing plate 41 to move downward or upward together. The pressing rod 42 can be a screw rod, a pneumatic telescopic rod, an electric telescopic rod or other motion mechanisms that can complete linear reciprocating movement.

[0057] Please refer to Figure 1 、 Figure 2 and Figure 4 . In some possible embodiments, an adjustment hole is provided at the top of the protective housing 10, the pressure rod 42 is in threaded fit with the adjustment hole, and one end of the pressure rod 42 accommodated in the accommodation cavity abuts against the transport pressing plate 41; the pressing mechanism 40 further includes an elastic connecting member 43, and the elastic connecting member 43 is connected between the transport pressing plate 41 and the protective housing 10 and is configured with an elastic pre-tightening force for moving the transport pressing plate 41 upward.

[0058] In this embodiment, the pressure rod 42 is a screw rod, the pressure rod 42 is in threaded fit with the adjustment hole, the bottom of the pressure rod 42 abuts against the transport pressing plate 41, and rotating the pressure rod 42 can drive the transport pressing plate 41 to move downward, and the elastic connecting member 43 is further stretched. When transported to the designated location, the pressure rod 42 can be rotated in the reverse direction, and under the action of the elastic pre-tightening force, the transport pressing plate 41 moves upward and separates from the rotor 31.

[0059] Please refer to Figure 1 、 Figure 2 and Figure 4 . In some possible embodiments, the elastic connecting member 43 is a spring, a rubber strip or other components capable of storing elastic force.

[0060] Please refer to Figure 4 . In some possible embodiments, the transport pressing plate 41 is annular, there are a plurality of pressure rods 42, and the plurality of pressure rods 42 are arranged at intervals along the circumference of the transport pressing plate 41. The elastic connecting member 43 and the adjustment hole correspond to the pressure rods 42 one by one. Designing the pressure rods 42 as a plurality in this embodiment helps to make the pressure exerted by the transport pressing plate 41 on the rotor 31 uniform.

[0061] Please refer to Figure 1 and Figure 4 . In some possible embodiments, the lower support mechanism 33 includes a hydrodynamic bearing 331 and a damper 332. The hydrodynamic bearing 331 is disposed in the accommodation cavity and is connected to the lower part of the rotor 31. The hydrodynamic bearing 331 is specifically a spiral groove hydrodynamic bearing 331; the damper 332 is disposed in the accommodation cavity and is connected below the hydrodynamic bearing 331, and the damper 332 can move vertically relative to the protective housing 10.

[0062] Please refer to Figure 1 and Figure 4, in some possible embodiments, the damper 332 includes a damper housing 3321 and a damper body 3322. The damper housing 3321 is provided at the lower part of the protective housing 10 and is in sealed cooperation with the inner wall of the accommodating cavity. The damper housing 3321 has a sealed cavity penetrating in the vertical direction, and an installation hole communicating with the sealed cavity is opened at the bottom of the damper housing 3321; the damper body 3322 includes a sealing part and an installation part. The sealing part is in sealed cooperation with the sealed cavity, the hydrodynamic bearing 331 is arranged above the sealing part, and the installation part is connected below the sealing part and is in threaded cooperation with the installation hole.

[0063] In this embodiment, the damper body 3322 and the damper housing 3321 are in threaded cooperation. By rotating the damper body 3322, its axial position can be adjusted, which is simple and convenient. In order to prevent the damper body 3322 from loosening due to vibration during use, after the flywheel energy storage cabinet device is installed at the designated position, an anti-loosening limit mechanism can be set to limit the rotation of the damper body 3322 to achieve the purpose of anti-loosening.

[0064] The anti-loosening limit mechanism can be a pressing rod 42 that can apply a pressing force to the damper body 3322, or a limit pin that can limit the damper body 3322, etc.

[0065] Please refer to Figure 1 , in some possible embodiments, an annular sealing groove is formed on the outer peripheral surface of the sealing part, and a sealing ring 3323 is arranged in the sealing groove to seal the joint surface between the sealing part and the sealed cavity and ensure the vacuum inside the accommodating cavity. One or more sealing grooves and sealing rings 3323 can be provided as needed.

[0066] It can be understood that the various parts in the above embodiments can be freely combined or deleted to form different combined embodiments. The specific contents of each combined embodiment will not be elaborated here. After this explanation, it can be considered that the specification of the present utility model has recorded each combined embodiment and can support different combined embodiments.

[0067] The above are only the preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A flywheel energy storage device, characterized in that: include: A protective shell having a receiving cavity formed therein, and a side wall of the protective shell having a supporting portion; A stator is arranged in the accommodating cavity along a vertical direction; A rotor shaft assembly, comprising a rotor, a magnetic bearing and a lower support mechanism respectively accommodated in the accommodating cavity, wherein the rotor is coaxially arranged with the stator and located above the support portion, the magnetic bearing is arranged above the rotor and coaxially arranged with the rotor, and the lower support mechanism is arranged below the rotor, and the lower support mechanism can move in a vertical direction; as well as A pressing mechanism, arranged in the protective housing and located above the rotor, the pressing mechanism having a pressing portion capable of moving vertically; The rotor has a transport posture and a working posture. When in the transport posture, the bottom of the rotor abuts against the support portion, and the pressing portion abuts against the upper portion of the rotor; when in the working posture, there is a first gap between the rotor and the support portion, and a second gap between the rotor and the pressing portion.

2. The flywheel energy storage device according to claim 1, characterized in that: The protective housing comprises: The cylinder sleeve is a cylindrical member, the cylinder sleeve has an inner cavity penetrating in the vertical direction, the support portion is arranged in the inner cavity, and the lower support mechanism is arranged at the lower part of the cylinder sleeve; and The cylinder cover is arranged above the cylinder liner. The cylinder cover and the cylinder liner enclose the accommodating cavity. The stator, the clamping mechanism and the magnetic bearing are respectively connected to the cylinder cover.

3. The flywheel energy storage device according to claim 1, characterized in that: The clamping mechanism comprises: a transport pressing plate, disposed in the accommodating cavity and located above the rotor, the transport pressing plate forming the pressing portion; and A pressure rod is arranged on the protective shell and connected to the transport pressure plate. The pressure rod can move vertically relative to the protective shell.

4. The flywheel energy storage device according to claim 3, characterized in that: An adjustment hole is provided on the top of the protective shell, the pressure rod is threadedly matched with the adjustment hole, and one end of the pressure rod accommodated in the accommodating cavity abuts against the transport pressure plate; The clamping mechanism also includes an elastic connecting member, which is connected between the transport pressing plate and the protective shell and is configured with an elastic pre-tightening force that causes the transport pressing plate to move upward.

5. The flywheel energy storage device according to claim 4, characterized in that: The elastic connecting member is a spring.

6. The flywheel energy storage device according to claim 4, characterized in that: The transport platen is annular, and a plurality of pressure rods are provided. The plurality of pressure rods are arranged at intervals along the circumference of the transport platen, and the elastic connectors and the adjustment holes correspond to the pressure rods one by one.

7. The flywheel energy storage device according to claim 1, characterized in that: The lower supporting mechanism comprises: a hydrodynamic bearing, disposed in the accommodating cavity and connected to the lower portion of the rotor; and A damper is arranged in the accommodating cavity and connected below the hydrodynamic bearing. The damper can move vertically relative to the protective shell.

8. The flywheel energy storage device according to claim 7, characterized in that: The damper comprises: A damper housing is disposed at the lower part of the protective housing and is sealed with the inner wall of the accommodating cavity. The damper housing has a sealed cavity that passes through in the vertical direction, and a mounting hole that communicates with the sealed cavity is opened at the bottom of the damper housing; and The damper body comprises a sealing part and a mounting part, wherein the sealing part is sealed and matched with the sealing cavity, the dynamic pressure bearing is arranged above the sealing part, and the mounting part is connected to the bottom of the sealing part and is threadedly matched with the mounting hole.

9. The flywheel energy storage device according to claim 8, characterized in that: An annular sealing groove is formed on the outer peripheral surface of the sealing portion, and a sealing ring is arranged in the sealing groove.

10. The flywheel energy storage device according to claim 7, characterized in that: The hydrodynamic bearing is a spiral groove hydrodynamic bearing.

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