A multi-bearing segmented flywheel energy storage device

Abstract

The application discloses a multi-bearing segmented flywheel energy storage device, which comprises an upper bearing, a lower bearing, a middle bearing, a shell, a rotating shaft, a first flywheel and a second flywheel. The two flywheels are arranged on the rotating shaft, the shell is arranged outside the flywheels and the rotating shaft, the upper bearing and the lower bearing are arranged at two ends of the rotating shaft, the middle bearing is arranged on the rotating shaft between the two flywheels, and the middle bearing is arranged between the shell and the rotating shaft. The first flywheel is integrally formed with the rotating shaft, and the second flywheel is detachably connected with the rotating shaft. The application is used to solve the problem of excessive radial vibration caused by the first critical speed being too low due to the large axial span of the flywheel. The flywheel body with large thickness is divided into two parts, which is beneficial to the uniformity of the heat treatment of the flywheel body. The radial strength of the rotating shaft of the flywheel body is improved by additionally arranging a bearing between the two flywheel bodies. In order to facilitate the installation of the bearing at the middle position of the flywheel, the segmented flywheel rotating shaft and the matched shell are designed.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of energy storage technology, in particular to a multi-bearing segmented flywheel energy storage device. BACKGROUND

[0002] At present, flywheel energy storage system has been successfully applied to uninterrupted power supply, renewable energy photovoltaic power generation and wind power generation, peak shaving, and hybrid electric vehicles. Flywheel energy storage system is composed of flywheel energy storage device and electric control system. The flywheel shaft in the flywheel energy storage device operates at high speed to realize energy storage in the form of mechanical energy. The electric control system is responsible for the conversion of electrical energy and mechanical energy, as well as the monitoring and control of the flywheel energy storage device.

[0003] The flywheel body as the main energy storage device of the flywheel energy storage system is generally made of metal material or composite material. According to the calculation formula of centrifugal stress of rotating body, the centrifugal stress is limited by the strength of the material. Therefore, under the condition of certain speed and material, the maximum safe diameter of the flywheel body is determined. In order to obtain more storage energy, the flywheel body needs to be thickened along the axial direction. The greater the thickness of the flywheel body, the greater the axial span of the entire flywheel shaft. The critical speed of the flywheel shaft is also lower, and the bending deformation is large, which is easy to lose stability during operation of the shaft.

[0004] At present, the commonly used bearing of flywheel energy storage shaft is mechanical bearing or electromagnetic bearing. Generally, two radial bearings and one axial bearing are used. The radial bearings are generally distributed on the upper and lower sides of the shaft, and the flywheel body and motor are arranged between the two bearings. The axial bearing is generally arranged at the top of the shaft. The metal flywheel body is generally designed as an integral type with the shaft, and the composite material flywheel body is generally nested and fitted on the metal hub with interference. Due to the limitation of bearing span, the flywheel shaft is generally short, or the diameter of the shaft is thickened to meet the requirement of radial stiffness. SUMMARY

[0005] The technical problem to be solved by the present application is to solve the above-mentioned problems of the prior art. The present application provides a radial bearing distribution mode for large-span flywheel shaft, which is used to solve the problem of excessive radial vibration caused by low first-order critical speed due to large axial span of the flywheel shaft. The flywheel body with large thickness is divided into two parts, which is beneficial to the uniformity of heat treatment of the flywheel body. By additionally installing bearings between the two flywheel bodies, the radial strength of the flywheel shaft is improved. In order to facilitate the installation of the bearing at the middle position of the flywheel, a segmented flywheel shaft is designed, and a matching shell design is also designed.

[0006] To solve the above technical problems, the technical scheme adopted by the present application is:

[0007] The application discloses a multi-bearing segmented flywheel energy storage device, which comprises an upper bearing, a lower bearing, an intermediate bearing, a shell, a rotating shaft, a first flywheel and a second flywheel.

[0008] As a further preferred embodiment of the application, the first flywheel is integrally formed with the rotating shaft, and the second flywheel is detachably connected with the rotating shaft.

[0009] As a further preferred embodiment of the application, the rotating shaft between the first flywheel and the second flywheel and the second flywheel are each provided with corresponding toothed structures, the toothed structures comprise protruding teeth and recessed teeth, the protruding teeth of one toothed structure are inserted into the recessed teeth of the other toothed structure, and the second flywheel is connected with the rotating shaft in a splined connection mode.

[0010] As a further preferred embodiment of the application, the tooth width ratio of the protruding teeth and the recessed teeth is 1:1.

[0011] As a further preferred embodiment of the application, the upper bearing and the lower bearing are electromagnetic bearings or mechanical bearings, and the intermediate bearing is a mechanical bearing.

[0012] As a further preferred embodiment of the application, when the upper bearing and the lower bearing are electromagnetic bearings and the intermediate bearing is a mechanical bearing, the gap between the electromagnetic bearing and the rotating shaft is a, the gap between the mechanical bearing and the rotating shaft is b, and a > b.

[0013] As a further preferred embodiment of the application, the application further comprises a motor, the motor is connected with the rotating shaft and drives the rotating shaft to rotate.

[0014] As a further preferred embodiment of the application, the application further comprises an axial force magnetic bearing, the axial force magnetic bearing is arranged between the shell and the rotating shaft.

[0015] As a further preferred embodiment of the application, the shell comprises a base shell, an intermediate shell and an upper shell, the lower bearing and the motor are arranged in the base shell, the first flywheel, the second flywheel and the intermediate bearing are wrapped by the intermediate shell, and the upper bearing and the axial force magnetic bearing are arranged in the upper shell.

[0016] As a further preferred embodiment of the application, the intermediate bearing is arranged at a middle position of the rotating shaft, and a reinforcing rib is arranged at a bearing mounting position in a radial direction.

[0017] The application has the following beneficial effects:

[0018] 1. Compared with other methods of designing radial bearings only in the upper and lower positions of the flywheel rotating shaft, the present application additionally has a radial bearing in the middle position. The layout of three bearings can allow the rotating shaft to have a longer axial length than when supported by two bearings. It can also increase the critical speed of the rotating shaft without increasing the diameter of the rotating shaft, avoiding bending deformation of the rotating shaft due to the critical speed.

[0019] 2. By using upper and lower magnetic bearings and a middle mechanical bearing, additional radial force can be provided when the rotating shaft passes through the critical speed, avoiding instability of the rotating shaft or collision between the rotating shaft and the shell due to excessive deformation.

[0020] 3. Ensure the safe and stable passage of the rotating shaft through the critical speed region.

[0021] 4. The thick flywheel body is divided into two parts, which is beneficial to the uniformity of the flywheel body heat treatment. By additionally installing bearings between the two flywheel bodies, the radial strength of the flywheel body rotating shaft is improved. In order to facilitate the installation of the bearing in the middle position of the flywheel, a segmented flywheel rotating shaft is designed, as well as a matching shell design. BRIEF DESCRIPTION OF DRAWINGS

[0022] Fig. 1 is the assembly explosion drawing of the present application;

[0023] Fig. 2 is the pinion type fitting schematic diagram of the present application;

[0024] Fig. 3 is the general assembly structure schematic diagram of the present application.

[0025] Among them: 1. Upper bearing; 2. Middle bearing; 3. Lower bearing; 4. First flywheel; 5. Second flywheel; 6. Rotating shaft; 7. Upper shell; 8. Middle shell; 9. Base shell; 10. Axial force magnetic bearing; 11. Convex tooth; 12. Concave tooth; 13. Motor. DETAILED DESCRIPTION

[0026] The present application will be further described in detail below in combination with the drawings and specific preferred embodiments.

[0027] In the description of the present application, it should be understood that the terms "left side", "right side", "upper part", "lower part" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and "first", "second" and the like do not represent the importance of the parts, so it cannot be understood as a limitation on the present application. The specific dimensions used in the present embodiment are only for the purpose of illustrating the technical scheme and do not limit the protection scope of the present application.

[0028] As shown in Figs. 1-3 A multi-bearing segmented flywheel energy storage device, comprising an upper bearing 1, a lower bearing 3, a middle bearing 2, a shell, a rotating shaft 6, a first flywheel 4 and a second flywheel 5; two flywheels are arranged on the rotating shaft 6, the shell is arranged outside the flywheels and the rotating shaft 6, the upper bearing 1 and the lower bearing 3 are arranged at both ends of the rotating shaft 6, and the middle bearing is arranged on the rotating shaft 6 between the two flywheels and between the shell and the rotating shaft 6. The middle bearing 2 is arranged at the middle position of the rotating shaft 6, and the bearing mounting position is radially reinforced with a reinforcing rib, thereby reducing the mass of the shell while ensuring the strength unchanged.

[0029] The main purpose of the present application is to provide a flywheel shaft bearing arrangement to reduce the influence of flywheel flexible deformation caused by excessive flywheel shaft span on high-speed rotation, and based on this bearing arrangement, a segmented flywheel shaft structure and a three-section shell structure design scheme are designed.

[0030] The present application provides a flywheel shaft radial bearing design and a segmented flywheel shaft and shell design cooperating therewith. Compared with the common mechanical bearing or electromagnetic bearing arranged above and below, the present application focuses on arranging an additional mechanical bearing at the middle position of the flywheel, forming an upper-middle-lower three-bearing arrangement structure. The three bearings are more conducive to the structural stability of the equal-span shaft system of the double flywheel.

[0031] The first flywheel 4 is integrally formed with the rotating shaft 6, and the second flywheel 5 is connected with the rotating shaft 6 in a detachable manner. The rotating shaft 6 between the first flywheel 4 and the second flywheel 5 and the second flywheel 5 are each provided with a corresponding toothed structure, the toothed structure comprising a male tooth 11 and a female tooth 12, the male tooth 11 of one toothed structure being inserted into the female tooth 12 of the other toothed structure; the second flywheel 5 is connected with the rotating shaft 6 in a pin-tooth type connection. The present application provides a combination mode of double flywheel shafts, which can increase the energy storage capacity of the flywheel energy storage system, and is also conducive to the uniformity of the heat treatment of the metal rotating shaft 6, thereby improving the stability of the high-speed rotation of the flywheel body. In order to ensure that the middle bearing can be installed between the two flywheel bodies, the flywheel body is assembled in a segmented manner, i.e., the first flywheel 4 is integrally manufactured with the rotating shaft 6, and the second flywheel 5 is sleeved with the rotating shaft 6. The sleeved flywheel body and the rotating shaft 6 are connected in a pin-tooth type connection, and the tooth width ratio of the male tooth 11 and the female tooth 12 is 1:1. This ensures good torque transmission and equivalent rotation strength.

[0032] The upper bearing 1 and the lower bearing 3 are electromagnetic bearings or mechanical bearings, and the intermediate bearing 2 is a mechanical bearing. The motor 13 is connected with the rotating shaft 6 and drives the rotating shaft 6 to rotate. The intermediate bearing 2, the upper bearing 1 and the lower bearing 3 are radial bearings, and the axial force magnetic bearing 10 is an axial bearing, which is arranged between the rotating shaft 6 at the top end and the upper shell 7. When the three radial bearings are designed as mechanical bearings, the inner ring of the bearing is tightly matched with the rotating shaft 6, and the outer ring of the bearing is matched with the flywheel shell. After the rotating shaft 6 rotates, the three radial bearings work at the same time to provide radial support force for the large-span flywheel rotating shaft 6, improve the first-order critical speed of the rotating shaft 6, and ensure that the design operating speed of the rotating shaft 6 is always below the critical speed, so that the rotating shaft 6 will not be flexibly bent.

[0033] When the upper bearing 1 and the lower bearing 3 are electromagnetic bearings and the intermediate bearing 2 is a mechanical bearing, the gap between the electromagnetic bearing and the rotating shaft 6 is a, the gap between the mechanical bearing and the rotating shaft 6 is b, and a > b. When the rotating speed of the rotating shaft 6 is low, the rotating shaft 6 is in a rigid state, and only the upper and lower electromagnetic bearings provide radial support force. When the rotating speed of the rotating shaft 6 reaches the first-order critical speed and the rotating shaft 6 is flexibly bent, the middle position of the rotating shaft 6 is bent to the largest extent, and will be in contact with the pre-designed middle bearing, which provides part of the support force to ensure that the flywheel stably passes through the first-order critical speed area. After the deformation of the rotating shaft 6 is restored, the middle bearing is out of the working state.

[0034] The shell includes a base shell 9, an intermediate shell 8 and an upper shell 7; the lower bearing 3 and the motor 13 are installed in the base shell 9; the first flywheel 4, the second flywheel 5 and the intermediate bearing 2 are wrapped in the intermediate shell 8; the upper bearing 1 and the axial force magnetic bearing 10 are installed in the upper shell 7. The intermediate bearing 2 is arranged in the radially inwardly recessed part in the middle of the intermediate shell 8.

[0035] The installation steps of the three-bearing segmented flywheel energy storage system are as follows: firstly, the lower bearing 3 and the motor 13 are installed in the base shell 9, and then the rotating shaft 6 is placed in the base shell 9 from top to bottom, and at this time the first flywheel 4 integrally manufactured with the rotating shaft 6 is placed on the base plane; then the intermediate shell 8 is passed through the rotating shaft 6 from top to bottom, covering the first flywheel 4 on the base; then the intermediate bearing 2 is fixedly installed between the rotating shaft 6 and the intermediate shell 8; then the second flywheel body 5 is installed through the rotating shaft 6, the second flywheel body 5 is inserted into the gear type cooperation with the integrated flywheel shaft, and then is fastened by screws in the axial direction; finally, the upper bearing 1 and the axial force magnetic bearing 10 are installed on the upper part of the rotating shaft 6 and in the upper shell 7, and the upper shell 7 is connected with the intermediate shell 8 from top to bottom.

[0036] When three mechanical bearings are used, the three radial bearings provide greater radial support force, the flywheel body with longer axial length can be designed, the critical speed of the rotating shaft 6 is improved, and the rotating shaft 6 can safely operate at the rated speed.

[0037] The preferred embodiments of the present application are described in detail above, but the present application is not limited to the specific details of the above-described embodiments. Within the technical concept of the present application, various equivalent transformations of the technical solutions of the present application can be made, and these equivalent transformations all belong to the protection scope of the present application.

Claims

1. A multi-bearing segmented flywheel energy storage device, characterized in that: It includes an upper bearing (1), a lower bearing (3), an intermediate bearing (2), a housing, a rotating shaft (6), a first flywheel (4) and a second flywheel (5), and a motor (13); the two flywheels are set on the rotating shaft (6), the housing is set outside the flywheels and the rotating shaft (6), the upper bearing (1) and the lower bearing (3) are set at both ends of the rotating shaft (6), the intermediate bearing (2) is located on the rotating shaft (6) between the two flywheels, and the intermediate bearing (2) is set between the housing and the rotating shaft (6); the upper bearing (1) and the lower bearing (3) are electromagnetic bearings, the intermediate bearing (2) is a mechanical bearing, the gap between the electromagnetic bearing and the rotating shaft (6) is a, the gap between the mechanical bearing and the rotating shaft (6) is b, and a>b; the motor (13) is connected to the rotating shaft (6) and drives the rotating shaft (6) to rotate.

2. The multi-bearing segmented flywheel energy storage device according to claim 1, characterized in that: The first flywheel (4) and the shaft (6) are integrally formed, and the second flywheel (5) and the shaft (6) are detachably connected.

3. The multi-bearing segmented flywheel energy storage device according to claim 2, characterized in that: The shaft (6) between the first flywheel (4) and the second flywheel (5) are provided with corresponding toothed structures. The toothed structures include convex teeth (11) and concave teeth (12). The convex teeth (11) of one toothed structure are inserted into the concave teeth (12) of another toothed structure. The connection between the second flywheel (5) and the shaft (6) is a toothed connection.

4. The multi-bearing segmented flywheel energy storage device according to claim 3, characterized in that: The tooth width ratio of the convex tooth (11) and the concave tooth (12) is 1:

1.

5. The multi-bearing segmented flywheel energy storage device according to claim 1, characterized in that: It also includes an axial bearing magnetic bearing (10), which is disposed between the housing and the rotating shaft (6).

6. The multi-bearing segmented flywheel energy storage device according to claim 5, characterized in that: The outer casing includes a base housing (9), an intermediate housing (8) and an upper housing (7); the lower bearing (3) and the motor (13) are installed inside the base housing (9); the intermediate housing (8) encloses the first flywheel (4), the second flywheel (5) and the intermediate bearing (2); the upper bearing (1) and the axial bearing magnetic bearing (10) are installed inside the upper housing (7).

7. The multi-bearing segmented flywheel energy storage device according to claim 1, characterized in that: The intermediate bearing (2) is located in the middle of the rotating shaft (6), and the bearing installation position is reinforced radially.

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