Building centralized energy supply system based on renewable energy sources

Abstract

The utility model relates to the technical field of renewable energy sources, in particular to a building centralized energy supply system based on renewable energy sources, which comprises lighting electric equipment, a hot water supply device, refrigeration load equipment, heat supply load equipment, a controller, an adjustable photovoltaic assembly, a solar sensor, a wind power generation assembly, a storage battery assembly, a first electronic switch and a second electronic switch. The system comprises a storage battery assembly, a hot water storage tank, a solar heat collector, a first circulating water pump, a first electric control valve, a buried pipe, a ground source heat pump unit, a second electric control valve, a second circulating water pump, a third electric control valve, a third circulating water pump and a fourth electric control valve. The solar energy collection efficiency is high, overshoot of the storage battery can be prevented, the service life of the storage battery is prolonged, the stability of the system is improved, geothermal energy and solar energy are used for preparing domestic hot water, heating and refrigerating, and the system is more energy-saving and environment-friendly.

Description

Technical Field

[0001] The utility model belongs to the technical field of renewable energy, in particular to a building centralized energy supply system based on renewable energy. Background Art

[0002] Renewable energy includes solar energy, hydropower, wind energy, biomass energy, wave energy, geothermal energy, etc. Solar energy and wind energy are used to provide electricity for buildings, and solar energy and geothermal energy are used for heating and cooling. Chinese patent document "201120499903.0" is a building energy-saving system that utilizes multiple renewable energy sources. It uses a wind-solar power generation public lighting system to provide lighting for the user side of the building by using wind power and photovoltaic complementarity. However, the system cannot control the photovoltaic components that receive sunlight and is in a fixed state. The sunlight will change due to season, time, and dimension, resulting in low efficiency in solar energy collection. When wind power generation and solar power generation are combined, it is necessary to combine batteries, inverters, etc. to provide electricity to the user side. When the user side does not use a large amount of electricity, it is very easy to cause overcharging of the battery, which will greatly affect the service life of the battery and cause the stability of the system to decrease. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide a building centralized energy supply system based on renewable energy in response to the above-mentioned defects. Through centralized control, solar energy and wind energy are used to store energy for battery components to supply power to the building's lighting and electrical equipment. The solar energy illumination effect is good and the collection efficiency is high. It can also prevent battery overcharge, increase the battery life, improve system stability, and use geothermal energy and solar energy to prepare domestic hot water and for heating and cooling.

[0004] The utility model adopts the following technical solutions to solve its technical problems: a centralized energy supply system for buildings based on renewable energy, including lighting electrical equipment, a hot water supply device, a refrigeration load device and a heating load device, a controller is arranged on the user side of the building, an adjustable photovoltaic assembly connected to the controller is arranged outside the building, and its orientation can be controlled by the controller according to the local sun direction, a sun sensor connected to the controller is arranged on the adjustable photovoltaic assembly, and the controller can control the orientation and tilt angle of the adjustable photovoltaic assembly according to the signal of the sun sensor, a wind power generation assembly connected to the controller is arranged outside the building at intervals with the adjustable photovoltaic assembly, a battery assembly connected to the wind power generation assembly, the adjustable photovoltaic assembly and the controller is arranged on the user side of the building, the battery assembly is connected to the lighting electrical equipment, and a first electronic switch and a second electronic switch connected to the controller are arranged between the battery assembly and the wind power generation assembly and the adjustable photovoltaic assembly;

[0005] A hot water storage tank connected to a hot water supply device is provided on the user side of the building, a solar collector connected to the hot water storage tank through a circulation pipeline is provided outside the building, and a first circulation water pump and a first electric control valve are provided on the circulation pipeline between the hot water storage tank and the solar collector;

[0006] An underground pipe is arranged outside the building, and a ground source heat pump unit connected to the underground pipe through a circulation pipeline is arranged on the user side of the building. The ground source heat pump unit is respectively connected to the refrigeration load equipment and the heating load equipment through the circulation pipeline. A second electric control valve is arranged on the circulation pipeline between the ground source heat pump unit and the underground pipe, a second circulation water pump and a third electric control valve are arranged on the circulation pipeline between the ground source heat pump unit and the refrigeration load equipment, and a third circulation water pump and a fourth electric control valve are arranged on the circulation pipeline between the ground source heat pump unit and the heating load equipment.

[0007] Furthermore, the hot water storage tank is connected to the buried pipe through a circulation pipeline, and a fourth circulation water pump and a fifth electric control valve connected to the controller are arranged on the circulation pipeline between the hot water storage tank and the buried pipe.

[0008] Furthermore, the hot water storage tank is connected to the ground source heat pump unit through a circulation pipeline, and a fifth circulation water pump and a sixth electric control valve connected to the controller are arranged on the circulation pipeline between the hot water storage tank and the ground source heat pump unit.

[0009] Furthermore, a temperature sensor connected to the controller is arranged inside the hot water storage tank.

[0010] Furthermore, the first circulating water pump, the first electric control valve, the second electric control valve, the second circulating water pump, the third electric control valve, the third circulating water pump and the fourth electric control valve are all connected to the controller.

[0011] Furthermore, the adjustable photovoltaic assembly includes a base, a supporting seat, a mounting frame, a photovoltaic panel, a first driving mechanism, a second driving mechanism, and a limit follower mechanism. The supporting seat is rotatably arranged on the base, the second driving mechanism is arranged at the bottom of the base, and drives the supporting seat to rotate on the base. Vertical columns in a vertical upward state are arranged on both sides of the upper surface of the supporting seat, the mounting frame is rotatably arranged between the two columns, the first driving mechanism is arranged on the column on one side, and drives the mounting frame to rotate between the two columns. The photovoltaic panels are evenly arranged on the mounting frame, the solar sensor is arranged on the mounting frame and spaced apart from the photovoltaic panel, and the limit follower mechanism is arranged on both sides of the supporting seat, so that the supporting seat is stably rotated on the base.

[0012] Furthermore, the first driving mechanism includes a driven gear, a driving gear, and a first motor. A rotating shaft on one side of the mounting frame rotatably arranged between the two columns passes through one side of the column and extends to the outside. The driven gear is sleeved on the rotating shaft outside the column. The first motor is arranged below the rotating shaft. The driving gear is arranged at the driving end of the first motor, and the driving gear is meshed with the driven gear.

[0013] Furthermore, the second driving mechanism includes a second motor disposed at the bottom end of the base, and a driving end of the second motor is connected to the bearing seat.

[0014] Furthermore, the limiting follower mechanism includes an annular limiting plate, an annular guide rail, a fixing part and a roller. The annular limiting plate is arranged on the base to surround the bearing seat. The annular guide rail is arranged on the inner circumferential wall of the annular limiting plate. The fixing part is symmetrically arranged on both sides of the bearing seat. The roller is rotatably arranged on the fixing part, and the outer surface of the roller is provided with a groove matching the annular guide rail.

[0015] The beneficial effects of the utility model are:

[0016] The utility model cooperates with the controller, the adjustable photovoltaic component, the wind power generation component, the solar sensor, the battery component, the first electronic switch of the inverter, and the second electronic switch. The adjustable photovoltaic component and the wind power generation component charge the battery component together, and then the battery component provides power to the lighting electrical equipment. When the controller detects that the battery charging reaches a safe value, the controller can control the first electronic switch and the second electronic switch to disconnect, stop the adjustable photovoltaic component and the wind power generation component from continuously charging the battery component, and prevent the battery component from overcharging, so as to increase the service life of the battery component and improve the stability of the system. The wind power generation component and the adjustable photovoltaic component can also be incorporated into the power grid, and when the battery does not need to be charged, they provide power storage to the power grid. In addition, the controller can control the adjustable photovoltaic component according to the signal of the solar sensor to adjust the direction and tilt angle of the photovoltaic panel along the direction of the sun, so that the photovoltaic panel as a whole is always exposed to sunlight in a larger area, so that the solar energy collection efficiency is higher.

[0017] Through the coordinated arrangement of the hot water storage tank, the solar collector, the first circulating water pump, the first electric control valve, the ground source heat pump unit, the second electric control valve, the second circulating water pump, the third electric control valve, the third circulating water pump, and the fourth electric control valve, according to the usage requirements of the user side, the controller drives the hot water storage tank, the solar collector, the first circulating water pump, the first electric control valve, the ground source heat pump unit, the second electric control valve, the second circulating water pump, the third electric control valve, the third circulating water pump, and the fourth electric control valve to work, so as to provide hot water to the hot water supply device on the user side throughout the year, and provide cooling and heating to the refrigeration load equipment and the heat load equipment, so as to supply energy to the building through centralized control. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The foregoing and other objects, features and advantages of the present invention will become apparent from the following detailed description in conjunction with the accompanying drawings.

[0019] Figure 1 It is a schematic diagram of the structure of the utility model.

[0020] Figure 2 It is a cross-sectional view of the adjustable photovoltaic module of the utility model.

[0021] Among them: 1. Lighting electrical equipment; 2. Hot water supply device; 3. Refrigeration load equipment; 301. Second circulating water pump; 302. Third electric control valve; 4. Heating load equipment; 401. Third circulating water pump; 402. Fourth electric control valve; 5. Controller; 6. Adjustable photovoltaic module; 601. Base; 602. Bearing seat; 603. Mounting frame; 604. Photovoltaic panel; 605. Column; 606. Driven gear; 607. Driving gear; 608. First motor; 610. Annular limit plate; 611. Annular guide rail; 612. Fixing piece; 613. Roller; 614, groove; 7, solar sensor; 8, wind power generation component; 9, battery component; 10, first electronic switch; 11, second electronic switch; 1201, hot water storage tank; 1202, solar collector; 1203, first circulating water pump; 1204, first electric control valve; 1205, fourth circulating water pump; 1206, fifth electric control valve; 1207, temperature sensor; 1301, buried pipe; 1302, ground source heat pump unit; 1303, second electric control valve; 1304, fifth circulating water pump; 1305, sixth electric control valve. DETAILED DESCRIPTION

[0022] The utility model is further described below in conjunction with the accompanying drawings.

[0023] Reference Figure 1-2 As shown, a centralized building energy supply system based on renewable energy includes lighting electrical equipment 1, a hot water supply device 2, a cooling load device 3 and a heating load device 4. A controller 5 is provided on the user side of the building, and an adjustable photovoltaic assembly 6 connected to the controller 5 is provided outside the building. The adjustable photovoltaic assembly 6 can be controlled by the controller 5 according to the local direction of the sun. A solar sensor 7 connected to the controller 5 is provided on the adjustable photovoltaic assembly 6. The controller 5 can control the direction and tilt angle of the adjustable photovoltaic assembly 6 according to the signal of the solar sensor 7.

[0024] The adjustable photovoltaic assembly 6 includes a base 601, a bearing seat 602, a mounting frame 603, a photovoltaic panel 604, a first driving mechanism, a second driving mechanism, and a limit follower mechanism. The bearing seat 602 is rotatably arranged on the base 601, and the second driving mechanism is arranged at the bottom of the base 601 to drive the bearing seat 602 to rotate on the base 601. Both sides of the upper surface of the bearing seat 602 are provided with vertically upward columns 605. The mounting frame 603 is rotatably arranged between the two columns 605. The first driving mechanism is arranged on the column 605 on one side to drive the mounting frame 603 to rotate between the two columns 605. The photovoltaic panel 604 is evenly arranged on the mounting frame 603. The solar sensor 7 is arranged on the mounting frame 603 and is spaced apart from the photovoltaic panel 604. The limit follower mechanism is arranged on both sides of the bearing seat 602, so that the bearing seat 602 is stably rotated on the base 601. The solar sensor 7 detects the position of the sun and transmits a signal to the controller 5. The controller 5 drives the second driving mechanism to work to rotate the bearing seat 602 so that the photovoltaic panel 604 is always facing the direction of the sun. At the same time, the controller 5 controls the first driving mechanism to work to drive the mounting frame 603 to rotate, so as to adjust the inclination angle of the photovoltaic panel 604, so that the photovoltaic panel as a whole is always facing the sunlight with a larger area, so that the solar energy collection efficiency is higher and the charging effect of the battery assembly 9 is better.

[0025] The first driving mechanism includes a driven gear 606, a driving gear 607, and a first motor 608. The rotating shaft on one side of the mounting frame 603 rotatingly arranged between the two columns 605 passes through one side column 605 and extends to the outside. The driven gear 606 is sleeved on the rotating shaft outside the column 605. The first motor 608 is arranged below the rotating shaft. The driving gear 607 is arranged at the driving end of the first motor 608. The driving gear 607 is meshed with the driven gear 606. The first motor 608 drives the driving gear 607 to rotate. Since the driving gear 607 is meshed with the driven gear 606, the driven gear 606 and the rotating shaft of the mounting frame 603 are driven to rotate to adjust the inclination angle between the mounting frame 603 and the sunlight, so that the photovoltaic panel as a whole is always facing the sunlight with a larger area, so that the solar energy collection efficiency is higher and the charging effect of the battery assembly 9 is better.

[0026] The second driving mechanism includes a second motor 609 disposed at the bottom end of the base 601 . The driving end of the second motor 609 is connected to the supporting base 602 . The second motor 609 and the first motor 608 are connected to the controller 5 .

[0027] The limiting follower mechanism includes an annular limiting plate 610, an annular guide rail 611, a fixing member 612 and a roller 613. The annular limiting plate 610 is arranged on the base 601 to surround the bearing seat 602. The annular guide rail 611 is arranged on the inner wall of the annular limiting plate 610. The fixing member 612 is symmetrically arranged on both sides of the bearing seat 602. The roller 613 is rotatably arranged on the fixing member 612. The outer surface of the roller 613 is provided with a groove 614 matching the annular guide rail 611. When the bearing seat 602 rotates, the roller 613 rolls along the annular guide rail 611, and cooperates with the annular guide rail 611 through the groove, so that the bearing seat 602 can stably rotate inside the annular limiting plate 610 to increase the working stability of the adjustable photovoltaic component 6.

[0028] A wind power generation assembly 8 connected to the controller 5 is arranged outside the building and spaced apart from the adjustable photovoltaic assembly 6. A battery assembly 9 connected to the wind power generation assembly 8, the adjustable photovoltaic assembly 6 and the controller 5 is arranged on the user side of the building. The battery assembly 9 is connected to the lighting electrical equipment 1. A first electronic switch 10 and a second electronic switch 11 connected to the controller 5 are arranged between the battery assembly 9 and the wind power generation assembly 8 and the adjustable photovoltaic assembly 6. The wind power generation assembly 8 and the adjustable photovoltaic assembly 6 are used to charge and store energy for the battery assembly 9. When the user side needs electricity for lighting, the battery assembly provides electricity to the user. When the controller 5 detects that the power in the battery assembly 9 is charged to a safe range, it controls the first electronic switch 10 and the second electronic switch 11 to disconnect the connection between the battery assembly 9 and the adjustable photovoltaic assembly 6 and the wind power generation assembly 8 to prevent the battery assembly 9 from overcharging when it is continuously charged, thereby protecting the battery assembly 9 and improving the service life of the battery assembly 9 and the stability of the system. The controller 5 can also control the adjustable photovoltaic assembly 6 and the wind power generation assembly 8 to stop working.

[0029] A hot water storage tank 1201 connected to the hot water supply device 2 is provided on the user side of the building, and a solar collector 1202 connected to the hot water storage tank 1201 through a circulation pipeline is provided outside the building. A first circulation water pump 1203 and a first electric control valve 1204 are provided on the circulation pipeline between the hot water storage tank 1201 and the solar collector 1202. The solar collector 1202 heats domestic water by absorbing solar thermal energy, and the first circulation water pump 1203 transfers the heat to the hot water storage tank 1201 via the first electric control valve 1204, so as to provide hot water to the hot water supply device 2 on the user side.

[0030] A buried pipe 1301 is arranged outside the building, and a ground source heat pump unit 1302 connected to the buried pipe 1301 through a circulation pipeline is arranged on the user side of the building. The ground source heat pump unit 1302 is respectively connected to the refrigeration load device 3 and the heating load device 4 through the circulation pipeline. A second electric control valve 1303 is arranged on the circulation pipeline between the ground source heat pump unit 1302 and the buried pipe 1301, a second circulation water pump 301 and a third electric control valve 302 are arranged on the circulation pipeline between the ground source heat pump unit 1302 and the refrigeration load device 3, and a third circulation water pump 401 and a fourth electric control valve 402 are arranged on the circulation pipeline between the ground source heat pump unit 1302 and the heating load device 4.

[0031] During cooling, the heat absorbed by the refrigeration load device enters the ground source heat pump unit 1302 through the second circulating water pump 301 and the third electric control valve 302, and then enters the buried pipe 1301 through the second electric control valve 1303 to be released into the soil for heat exchange and cooling, and then is sent back to the refrigeration load device 3 from the circulating pipe to the ground source heat pump unit 1302.

[0032] During heating, the heating medium in the heating load device 4 is sent into the ground source heat pump unit 1302 through the third circulating water pump 401 and the fourth electric control valve 402, and then sent into the buried pipe 1301 through the second electric control valve 1303, where it contacts and exchanges heat with the soil to heat the heating medium in the buried pipe 1301, and then sent to the heating load device 4 through the circulating pipe and the ground source heat pump unit 1302, so as to provide continuous circulation heating to the user side.

[0033] The hot water storage tank 1201 is connected to the buried pipe 1301 through a circulation pipeline. The circulation pipeline between the hot water storage tank 1201 and the buried pipe 1301 is provided with a fourth circulation water pump 1205 and a fifth electric control valve 1206 connected to the controller 5. When heating and cooling are not needed, the controller 5 controls the second electric control valve 1303 to close, disconnects the buried pipe 1301 from the ground source heat pump unit 1302, and the controller 5 controls the fourth circulation water pump 1205 and the fifth electric control valve 1206 to open and work. The hot water in the hot water storage tank 1201 heated by the solar collector 1202 enters the buried pipe 1301 through the fourth circulation water pump 1205 and the fifth electric control valve 1206, releases the heat into the soil, and stores heat for the land to prevent the soil temperature from dropping during heating, causing the system to be unable to operate stably.

[0034] The hot water storage tank 1201 is connected to the ground source heat pump unit 1302 through a circulation pipeline. The circulation pipeline between the hot water storage tank 1201 and the ground source heat pump unit 1302 is provided with a fifth circulation water pump 1304 and a sixth electric control valve 1305 connected to the controller 5. A temperature sensor 1207 connected to the controller 5 is provided inside the hot water storage tank 1201. When the temperature sensor 1207 continuously detects the temperature in the hot water storage tank 1201 heated by the solar collector 1202, when the controller 5 receives and finds that the internal domestic water cannot meet the standard temperature, the controller 5 controls the sixth electric control valve 1305 and the fifth circulation water pump 1304 to open and work, so that the domestic water is sent into the buried pipe 1301 through the ground source heat pump unit 1302 and the second electric control valve 1303 to be heated by the soil, and then sent into the hot water storage tank 1201 through the circulation pipe and the ground source heat pump unit 1302, so that it can provide hot water to the user side throughout the year.

[0035] The first circulating water pump 1203, the first electric control valve 1204, the second electric control valve 1303, the second circulating water pump 301, the third electric control valve 302, the third circulating water pump 401 and the fourth electric control valve 402 are all connected to the controller 5. The controller 5 can control its working state according to the usage requirements of the user side to form centralized control and supply energy for the building.

[0036] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A building centralized energy supply system based on renewable energy, comprising lighting electrical equipment (1), a hot water supply device (2), a cooling load device (3) and a heating load device (4), characterized in that: A controller (5) is provided on the user side of the building, an adjustable photovoltaic assembly (6) connected to the controller (5) is provided outside the building and can be controlled by the controller (5) according to the local direction of the sun, a sun sensor (7) connected to the controller (5) is provided on the adjustable photovoltaic assembly (6), and the controller (5) can control the direction and tilt angle of the adjustable photovoltaic assembly (6) according to the signal of the sun sensor (7), a wind power generation assembly (8) connected to the controller (5) is arranged outside the building at intervals from the adjustable photovoltaic assembly (6), a battery assembly (9) connected to the wind power generation assembly (8), the adjustable photovoltaic assembly (6) and the controller (5) is provided on the user side of the building, the battery assembly (9) is connected to the lighting electrical equipment (1), and a first electronic switch (10) and a second electronic switch (11) connected to the controller (5) are provided between the battery assembly (9) and the wind power generation assembly (8) and the adjustable photovoltaic assembly (6); A hot water storage tank (1201) connected to a hot water supply device (2) is provided on the user side of the building, a solar collector (1202) connected to the hot water storage tank (1201) via a circulation pipeline is provided outside the building, and a first circulation water pump (1203) and a first electric control valve (1204) are provided on the circulation pipeline between the hot water storage tank (1201) and the solar collector (1202); A buried pipe (1301) is arranged outside the building, and a ground source heat pump unit (1302) connected to the buried pipe (1301) through a circulation pipeline is arranged on the user side of the building. The ground source heat pump unit (1302) is connected to a cooling load device (3) and a heating load device (4) through the circulation pipeline respectively. A second electric control valve (1303) is arranged on the circulation pipeline between the ground source heat pump unit (1302) and the buried pipe (1301), a second circulation water pump (301) and a third electric control valve (302) are arranged on the circulation pipeline between the ground source heat pump unit (1302) and the cooling load device (3), and a third circulation water pump (401) and a fourth electric control valve (402) are arranged on the circulation pipeline between the ground source heat pump unit (1302) and the heating load device (4).

2. The building centralized energy supply system based on renewable energy according to claim 1 is characterized in that: The hot water storage tank (1201) is connected to the buried pipe (1301) via a circulation pipeline, and a fourth circulation water pump (1205) and a fifth electric control valve (1206) connected to a controller (5) are provided on the circulation pipeline between the hot water storage tank (1201) and the buried pipe (1301).

3. The building centralized energy supply system based on renewable energy according to claim 1 is characterized in that: The hot water storage tank (1201) is connected to the ground source heat pump unit (1302) via a circulation pipeline, and a fifth circulation water pump (1304) and a sixth electric control valve (1305) connected to a controller (5) are provided on the circulation pipeline between the hot water storage tank (1201) and the ground source heat pump unit (1302).

4. The building centralized energy supply system based on renewable energy according to claim 3 is characterized by: The hot water storage tank (1201) is provided with a temperature sensor (1207) connected to the controller (5).

5. The building centralized energy supply system based on renewable energy according to claim 1 is characterized in that: The first circulating water pump (1203), the first electric control valve (1204), the second electric control valve (1303), the second circulating water pump (301), the third electric control valve (302), the third circulating water pump (401) and the fourth electric control valve (402) are all connected to the controller (5).

6. The building centralized energy supply system based on renewable energy according to claim 1 is characterized by: The adjustable photovoltaic assembly (6) comprises a base (601), a bearing seat (602), a mounting frame (603), a photovoltaic panel (604), a first driving mechanism, a second driving mechanism, and a position limiting follower mechanism. The bearing seat (602) is rotatably arranged on the base (601). The second driving mechanism is arranged at the bottom end of the base (601) to drive the bearing seat (602) to rotate on the base (601). Vertical columns (605) in a vertically upward state are arranged on both sides of the upper surface of the bearing seat (602). The mounting frame (603) is provided with a plurality of vertical columns (605). 03) is rotatably arranged between the two columns (605), the first driving mechanism is arranged on the column (605) on one side, driving the mounting frame (603) to rotate between the two columns (605), the photovoltaic panels (604) are evenly arranged on the mounting frame (603), the solar sensor (7) is arranged on the mounting frame (603), and is spaced apart from the photovoltaic panels (604), and the limit follower mechanism is arranged on both sides of the bearing seat (602), so that the bearing seat (602) is stably mounted on the base (601) to rotate.

7. The building centralized energy supply system based on renewable energy according to claim 6 is characterized in that: The first driving mechanism comprises a driven gear (606), a driving gear (607), and a first motor (608). A rotating shaft on one side of the mounting frame (603) rotatably arranged between the two columns (605) passes through one column (605) and extends to the outside. The driven gear (606) is sleeved on the rotating shaft outside the column (605). The first motor (608) is arranged below the rotating shaft. The driving gear (607) is arranged at the driving end of the first motor (608). The driving gear (607) is meshed with the driven gear (606).

8. The building centralized energy supply system based on renewable energy according to claim 6 is characterized by: The second driving mechanism comprises a second motor (609) arranged at the bottom end of the base (601), and a driving end of the second motor (609) is connected to the supporting base (602).

9. The building centralized energy supply system based on renewable energy according to claim 6, characterized in that: The limiting follower mechanism comprises an annular limiting plate (610), an annular guide rail (611), a fixing member (612) and a roller (613); the annular limiting plate (610) is arranged on the base (601) to surround the bearing seat (602); the annular guide rail (611) is arranged on the inner peripheral wall of the annular limiting plate (610); the fixing member (612) is symmetrically arranged on both sides of the bearing seat (602); the roller (613) is rotatably arranged on the fixing member (612); and the outer surface of the roller (613) is provided with a groove (614) matching the annular guide rail (611).

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