CN115263995A

CN115263995A - Multi-bearing sectional type flywheel energy storage device

Info

Publication number: CN115263995A
Application number: CN202210937761.4A
Authority: CN
Inventors: 张志来; 戴兴建; 胡东旭; 张华良; 陈海生; 徐玉杰; 徐鲍; 王继平
Original assignee: Zhongke Nanjing Future Energy System Research Institute; Institute of Engineering Thermophysics of CAS
Current assignee: Zhongke Nanjing Future Energy System Research Institute; Institute of Engineering Thermophysics of CAS
Priority date: 2022-08-05
Filing date: 2022-08-05
Publication date: 2022-11-01

Abstract

The invention discloses a multi-bearing sectional type 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, wherein the upper bearing is arranged on the shell; 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 located on the rotating shaft between the two flywheels, and the middle bearing is arranged between the shell and the rotating shaft. The first flywheel and the rotating shaft are integrally formed, and the second flywheel and the rotating shaft are detachably connected. The invention is used for solving the problem of overlarge radial vibration caused by the overlow first-order critical rotating speed 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 installing the bearing between the two flywheel bodies. In order to facilitate the installation of the bearing at the middle position of the flywheel, the sectional flywheel rotating shaft and the shell design matched with the sectional flywheel rotating shaft are designed.

Description

Multi-bearing sectional type flywheel energy storage device

Technical Field

The invention relates to the technical field of energy storage, in particular to a multi-bearing sectional type flywheel energy storage device.

Background

At present, a flywheel energy storage system is successfully applied to the fields of uninterruptible power supplies, renewable energy photovoltaic power generation, peak shaving of wind power generation, hybrid electric vehicles and the like. The flywheel energy storage system consists of a flywheel energy storage device and an electric control system, a flywheel rotating shaft in the flywheel energy storage device runs at a high speed, and energy storage is realized in a mechanical energy mode; the electric control system is responsible for energy conversion between electric energy and mechanical energy and monitoring and controlling the flywheel energy storage device.

The flywheel body is used as a main energy storage device of a flywheel energy storage system, generally made of metal materials or composite materials, and centrifugal stress is limited by material strength according to a calculation formula of centrifugal stress of a rotating body, so that the maximum safe diameter of the flywheel body is determined under the condition of certain rotating speed and materials. To obtain more stored energy, the flywheel mass needs to be thickened axially. The greater the thickness of the flywheel mass, the greater the axial span of the entire flywheel shaft. The lower the critical rotating speed of the flywheel rotating shaft is, the larger the bending deformation is, and the rotating shaft is easy to be unstable in the running process.

At present, a bearing commonly used for a flywheel energy storage rotating shaft is a mechanical bearing or an electromagnetic bearing. The bearings are generally two radial bearings and one axial bearing, the radial bearings are generally distributed on the upper side and the lower side of the rotating shaft, the flywheel body, the motor and the like are arranged between the two bearings, and the axial bearing is generally arranged at the top of the rotating shaft. The metal flywheel body and the rotating shaft are designed into a whole, and the composite material flywheel body is sleeved on the metal hub in a nesting interference mode. The flywheel shaft is generally short due to the limitation of the bearing span, or the diameter of the shaft is thickened to meet the requirement of radial rigidity.

Disclosure of Invention

The invention provides a radial bearing distribution mode for a large-span flywheel rotating shaft, aiming at overcoming the defects of the prior art, and aims to solve the problem of overlarge radial vibration caused by overlow first-order critical rotating speed due to large axial span of a 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 installing the bearing between the two flywheel bodies. In order to facilitate the installation of the bearing at the middle position of the flywheel, a sectional flywheel rotating shaft and a shell design mode matched with the sectional flywheel rotating shaft are designed.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows:

a multi-bearing sectional type flywheel energy storage device 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 located on the rotating shaft between the two flywheels, and the middle bearing is arranged between the shell and the rotating shaft.

As a further preferred aspect of the present invention, the first flywheel and the rotating shaft are integrally formed, and the second flywheel and the rotating shaft are detachably connected.

As a further preferred aspect of the present invention, the rotating shaft between the first flywheel and the second flywheel are both provided with corresponding tooth-like structures, each tooth-like structure includes a convex tooth and a concave tooth, and the convex tooth of one tooth-like structure is inserted into the concave tooth of the other tooth-like structure; the second flywheel is connected with the rotating shaft in a gear shaping mode.

As a further preferred aspect of the present invention, the tooth ratio of the convex teeth and the concave teeth is 1:1.

as a further preferred aspect of the present invention, the upper bearing and the lower bearing are electromagnetic bearings or mechanical bearings, and the intermediate bearing is a mechanical bearing.

As a further preferable aspect of the present invention, when the upper bearing and the lower bearing employ electromagnetic bearings and the intermediate bearing employs mechanical bearings, a gap between the electromagnetic bearings and the rotating shaft is a, a gap between the mechanical bearings and the rotating shaft is b, and a > b.

As a further optimization of the invention, the device also comprises a motor, wherein the motor is connected with the rotating shaft and drives the rotating shaft to rotate.

As a further preferred aspect of the present invention, the present invention further includes an axial force bearing magnetic bearing, and the axial force bearing magnetic bearing is disposed between the housing and the rotating shaft.

As a further preferable aspect of the present invention, the casing includes a base casing, an intermediate casing, and an upper casing; a lower bearing and a motor are arranged in the base shell; the middle shell wraps the first flywheel, the second flywheel and the middle bearing; an upper bearing and an axial force bearing magnetic bearing are arranged in the upper shell.

As a further preferable mode of the present invention, the intermediate bearing is disposed at a middle position of the rotating shaft, and a mode of a reinforcing rib is adopted in a radial direction at a bearing mounting position.

The invention has the following beneficial effects:

1. compared with other methods of designing radial bearings only at the upper position and the lower position of the flywheel rotating shaft, the method has the advantage that one radial bearing is additionally arranged at the middle position. The three-bearing arrangement allows the shaft to have a longer axial length than when supported by two bearings. The critical rotating speed of the rotating shaft can be improved under the condition that the diameter of the rotating shaft does not need to be increased, and the bending deformation of the rotating shaft due to the critical rotating speed is avoided.

2. The upper and lower magnetic bearings and the middle mechanical bearing are adopted, so that extra radial force can be provided when the rotating shaft passes through the critical rotating speed, and the instability of the rotating shaft or the collision and friction between the rotating shaft and the shell caused by excessive deformation can be avoided.

3. The rotating shaft can be ensured to safely and stably transit the critical rotating speed area.

4. 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 installing the bearing between the two flywheel bodies. In order to facilitate the installation of the bearing at the middle position of the flywheel, a sectional flywheel rotating shaft and a shell design mode matched with the sectional flywheel rotating shaft are designed.

Drawings

FIG. 1 is an exploded view of the assembly of the present invention;

FIG. 2 is a schematic view of the inventive gear shaping fit;

fig. 3 is a schematic view of the final assembly structure of the present invention.

Among them are: 1. an upper bearing; 2. a middle bearing; 3. a lower bearing; 4. a first flywheel; 5. a second flywheel; 6. a rotating shaft; 7. an upper housing; 8. a middle housing; 9. a base housing; 10. an axial force bearing magnetic bearing; 11. convex teeth; 12. concave teeth; 13. an electric motor.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and specific preferred embodiments.

In the description of the present invention, it should be understood that the terms "left side", "right side", "upper part", "lower part", etc. indicate orientations or positional relationships based on those shown in the drawings, only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, "first", "second", etc. do not represent an important degree of the component, and thus, are not to be construed as limiting the present invention. The specific dimensions used in the present example are only for illustrating the technical solution and do not limit the protection scope of the present invention.

As shown in fig. 1-3, a multi-bearing segmented flywheel energy storage device includes an upper bearing 1, a lower bearing 3, a middle bearing 2, a housing, a rotating shaft 6, a first flywheel 4 and a second flywheel 5; the 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 two ends of the rotating shaft 6, the middle bearing is arranged on the rotating shaft 6 between the two flywheels, and the middle bearing is arranged between the shell and the rotating shaft 6. The middle bearing 2 is arranged in the middle of the rotating shaft 6, and the mounting position of the bearing adopts a mode of reinforcing ribs in the radial direction, so that the quality of the shell is reduced, and the strength is ensured to be unchanged.

The invention mainly aims to provide an arrangement mode of a flywheel shafting bearing, aiming at reducing the influence of flywheel flexible deformation on high-speed rotation caused by overlarge flywheel shaft span, and designing a sectional type flywheel shaft body structure and a three-section type shell structure design scheme based on the bearing arrangement mode.

The invention provides a design mode of a radial bearing of a flywheel shaft system and a design of a sectional type flywheel shaft body and a shell matched with the radial bearing. Compared with the common mechanical bearing or electromagnetic bearing which is respectively arranged at the upper part and the lower part of the radial bearing, the radial bearing is characterized in that the mechanical bearing is additionally arranged at the middle part of the flywheel to form an arrangement structure of an upper bearing, a middle bearing and a lower bearing. The three bearings are more beneficial to the structural stability of the long-span shafting with double flywheels.

The first flywheel 4 and the rotating shaft 6 are integrally formed, and the second flywheel 5 and the rotating shaft 6 are detachably connected. The rotating shaft 6 between the first flywheel 4 and the second flywheel 5 are both provided with corresponding tooth-shaped structures, each tooth-shaped structure comprises a convex tooth 11 and a concave tooth 12, and the convex tooth 11 of one tooth-shaped structure is inserted into the concave tooth 12 of the other tooth-shaped structure; the second flywheel 5 is connected with the rotating shaft 6 in a gear shaping manner. The invention provides a combination mode of double flywheel shafts, the double flywheel shafts can increase the energy storage capacity of a flywheel energy storage system, meanwhile, the uniformity of heat treatment of the metal rotating shaft 6 is facilitated, and the stability of high-speed rotation of a flywheel body is improved. In order to ensure that the middle bearing can be arranged between the two flywheel bodies, the flywheel bodies are assembled in a sectional mode, namely the first flywheel 4 and the rotating shaft 6 are integrally manufactured, and the second flywheel 5 and the rotating shaft 6 are sleeved. Adopt gear shaping formula cooperation mode between the suit flywheel body and the pivot 6, the tooth width ratio of convex tooth 11 and concave tooth 12 is 1:1. this ensures good torque transmission and equivalent rotational strength.

The upper bearing 1 and the lower bearing 3 are electromagnetic bearings or mechanical bearings, and the middle bearing 2 is a mechanical bearing. The device also comprises a motor 13, wherein the motor 13 is connected with the rotating shaft 6 and drives the rotating shaft 6 to rotate. The middle bearing 2, the upper bearing 1 and the lower bearing 3 are all radial bearings, the axial bearing magnetic bearing 10 is an axial bearing, and the axial bearing magnetic bearing 10 is arranged between the rotating shaft 6 at the top end of the rotating shaft 6 and the upper shell 7. When the upper, middle and lower radial bearings are all designed by 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 simultaneously to provide radial supporting force for the large-span flywheel rotating shaft 6, the first-order critical rotating speed of the rotating shaft 6 is improved, and the rotating shaft 6 cannot be bent greatly when the designed operating rotating speed of the rotating shaft 6 is always at the critical rotating speed.

When the upper bearing 1 and the lower bearing 3 employ electromagnetic bearings and the intermediate bearing 2 employs mechanical bearings, the gap between the electromagnetic bearings and the rotating shaft 6 is a, the gap between the mechanical bearings and the rotating shaft 6 is b, and a > b. When the rotating shaft 6 is in a rigid state when the rotating shaft 6 rotates at a low speed, only the upper and lower electromagnetic bearings provide radial supporting force. When the rotating speed of the rotating shaft 6 reaches the first-order critical rotating speed and is flexibly bent, the middle position of the rotating shaft 6 is bent to the maximum degree and is contacted with a pre-designed middle bearing, and the middle bearing provides a part of supporting force to ensure that the flywheel stably passes through a first-order critical rotating speed area. After the rotating shaft 6 is deformed and recovered, the middle bearing is separated from the working state.

The shell comprises a base shell 9, a middle shell 8 and an upper shell 7; the lower bearing 3 and the motor 13 are arranged in the base shell 9; the middle shell 8 wraps the first flywheel 4, the second flywheel 5 and the middle bearing 2; the upper bearing 1 and the axial force bearing magnetic bearing 10 are arranged in the upper shell 7. The intermediate bearing 2 is arranged in a radially inwardly recessed portion at the middle of the intermediate housing 8.

The mounting steps of the three-bearing segmented flywheel energy storage system are as follows: firstly, a lower bearing 3 and a motor 13 are arranged in a base shell 9, then a rotating shaft 6 is placed in the base shell 9 from top to bottom, and a first flywheel 4 which is integrally manufactured with the rotating shaft 6 is placed on the upper plane of the base; then the middle shell 8 penetrates through the rotating shaft 6 from top to bottom to cover the first flywheel 4 on the base; then the middle bearing 2 is fixedly arranged between the rotating shaft 6 and the middle shell 8; then the second flywheel body 5 passes through the rotating shaft 6 to be installed, the second flywheel body 5 and the integrated flywheel shaft realize gear shaping type matching, and then the second flywheel body and the integrated flywheel shaft are fastened by screws along the axial direction; and finally, the upper bearing 1 and the axial force bearing magnetic bearing 10 are arranged on the upper part of the rotating shaft 6 and in the upper shell 7, and the upper shell 7 is connected with the middle shell 8 from top to bottom.

When three mechanical bearings are adopted, the three radial bearings provide larger radial supporting force, a flywheel body with longer axial length can be designed, the critical rotating speed of the rotating shaft 6 is improved, and the rotating shaft 6 can safely operate at the rated rotating speed.

Although the preferred embodiments of the present invention have been described in detail, the present invention is not limited to the details of the embodiments, and various equivalent modifications can be made within the technical spirit of the present invention, and the scope of the present invention is also within the scope of the present invention.

Claims

1. A multi-bearing segmented flywheel energy storage device is characterized in that: comprises 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); the 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 two ends of the rotating shaft (6), the middle bearing is positioned on the rotating shaft (6) between the two flywheels, and the middle bearing is arranged between the shell and the rotating shaft (6).

2. The multi-bearing segmented flywheel energy storage device of claim 1, wherein: the first flywheel (4) and the rotating shaft (6) are integrally formed, and the second flywheel (5) and the rotating shaft (6) are detachably connected.

3. The multi-bearing segmented flywheel energy storage device of claim 2, wherein: corresponding tooth-shaped structures are arranged on a rotating shaft (6) between the first flywheel (4) and the second flywheel (5) and on the second flywheel (5), each tooth-shaped structure comprises a convex tooth (11) and a concave tooth (12), and the convex tooth (11) of one tooth-shaped structure is inserted into the concave tooth (12) of the other tooth-shaped structure; the second flywheel (5) is connected with the rotating shaft (6) in a gear shaping manner.

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

5. the multi-bearing segmented flywheel energy storage device of claim 1, wherein: the upper bearing (1) and the lower bearing (3) are electromagnetic bearings or mechanical bearings, and the middle bearing (2) is a mechanical bearing.

6. The multi-bearing segmented flywheel energy storage device of claim 5, wherein: when the upper bearing (1) and the lower bearing (3) adopt electromagnetic bearings and the middle bearing (2) adopts a mechanical bearing, the clearance between the electromagnetic bearings and the rotating shaft (6) is a, the clearance between the mechanical bearings and the rotating shaft (6) is b, and a > b.

7. The multi-bearing segmented flywheel energy storage device of claim 1, wherein: the device also comprises a motor (13), wherein the motor (13) is connected with the rotating shaft (6) and drives the rotating shaft (6) to rotate.

8. The multi-bearing segmented flywheel energy storage device of claim 7, wherein: the axial force bearing magnetic bearing (10) is also included, and the axial force bearing magnetic bearing (10) is arranged between the shell and the rotating shaft (6).

9. The multi-bearing segmented flywheel energy storage device of claim 8, wherein: the shell comprises a base shell (9), a middle shell (8) and an upper shell (7); a lower bearing (3) and a motor (13) are arranged in the base shell (9); the middle shell (8) wraps the first flywheel (4), the second flywheel (5) and the middle bearing (2); an upper bearing (1) and an axial force bearing magnetic bearing (10) are arranged in the upper shell (7).

10. The multi-bearing segmented flywheel energy storage device of claim 1, wherein: the middle bearing (2) is arranged in the middle of the rotating shaft (6), and the mounting position of the bearing adopts a mode of reinforcing ribs in the radial direction.