Vacuum pump and application thereof in refrigerator

Abstract

The invention belongs to the field of vacuum pumps, and provides a vacuum pump and application thereof in refrigerators.The vacuum pump comprises a pump body, the pump body is composed of a bottom cover, a middle cover and an end cover, the middle cover is located between the bottom cover and the end cover, a motor is arranged on the side, away from the middle cover, of the bottom cover, and an output shaft of the motor extends to the inner side of the bottom cover to be connected with an eccentric wheel; the outer edge of the eccentric wheel is in contact with a leather cup support slidably connected with the bottom cover, and a guide hole is formed in the middle of the leather cup support. A leather cup and a steel needle linkage mechanism are adopted to replace an electromagnetic valve, a motor drives an eccentric wheel to drive a leather cup support to do reciprocating motion, a pull cup is pulled to do reciprocating deformation in the motion process, reciprocating air exhaust is conducted by changing the size of the space of a pump body cavity, working noise is effectively controlled, and meanwhile the air exhaust speed is increased; and compared with a traditional electromagnetic valve, the volume of the low-oxygen fresh-keeping electromagnetic valve is effectively reduced, and the space utilization rate in the working process is improved.

Description

Technical Field

[0001] This invention belongs to the field of vacuum pumps, specifically a vacuum pump and its application in refrigerators. Background Technology

[0002] Traditional refrigerator preservation technologies mainly focus on inhibiting the activity of microorganisms and enzymes in a low-temperature environment. However, food still faces key problems during refrigeration, such as oxidation caused by oxygen, dehydration and shriveling of fruits and vegetables or frost formation on the surface of meat due to humidity fluctuations, and accelerated ripening and decay of fruits and vegetables due to the accumulation of ethylene gas. Existing technologies use a vacuum device to extract air to achieve low-oxygen preservation.

[0003] However, existing vacuum pumping devices typically use solenoid valves to achieve vacuuming operations. The vibration of solenoid valves during exhaust generates significant noise, making it difficult to meet the requirements of medical, laboratory, and other applications with strict noise control requirements. Solenoid valves also occupy a large volume and are expensive, hindering the miniaturization of equipment and reducing the product's market competitiveness. Some devices use miniature vacuum pumps, but the vacuum level and pumping speed of miniature vacuum pumps are difficult to meet the stringent requirements of applications such as high-end home appliances.

[0004] To address the problems raised in the background art, those skilled in the art have proposed a vacuum pump and its application in refrigerators. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a vacuum pump and its application in a refrigerator.

[0006] A vacuum pump and its application in a refrigerator includes a pump body comprising a bottom cover, a middle cover, and an end cover. The middle cover is located between the bottom cover and the end cover. A motor is mounted on the side of the bottom cover opposite to the middle cover. The output shaft of the motor extends to the inside of the bottom cover and is connected to an eccentric wheel. A cup support that is slidably connected to the bottom cover is mounted on the outer edge of the eccentric wheel. A guide hole is provided in the middle of the cup support. A cup located inside the middle cover is mounted on the side of the cup support opposite to the eccentric wheel. A steel needle is embedded in the middle of the cup, and one end of the steel needle extends to the guide hole. On the inner side, a pull cup seat is provided on the side of the leather cup away from the leather cup support. The pull cup seat is located between the middle cover and the end cover. A pull cup is provided on the end face of the pull cup seat away from the leather cup, located inside the end cover. The middle and top of the end face of the end cover are respectively connected to the first air supply pipe and the second air supply pipe. One end of the second air supply pipe is connected to the air storage cylinder. One end of the first air supply pipe is connected to the filter cylinder located below the air storage cylinder. A backflush pipe is connected between the filter cylinder and the air storage cylinder. A pressurization component is provided inside the air storage cylinder for pressurizing when the backflush pipe is in the conducting state.

[0007] Preferably, the bottom of the filter cartridge opposite to the first air supply pipe is connected to an air inlet pipe, and a filter element is horizontally arranged inside the filter cartridge, which is directly opposite to the backflush pipe. The filter element is located between the air inlet pipe and the first air supply pipe.

[0008] Preferably, the bottom of the gas storage cylinder on the side away from the second gas supply pipe is connected to an exhaust pipe, and the exhaust pipe is positioned directly opposite the second gas supply pipe.

[0009] Preferably, the first gas supply pipe, the second gas supply pipe, the air inlet pipe, and the exhaust pipe are all equipped with a first one-way valve, and the backflush pipe is equipped with a second one-way valve.

[0010] Preferably, the bottom end of the filter cylinder is threadedly connected to an open sludge collection cylinder, and the end face where the filter cylinder connects to the open sludge collection cylinder is provided with a sludge discharge port, and an electric valve is installed in the sludge discharge port.

[0011] Preferably, the booster assembly includes a mounting plate, compression springs, a piston, and a retaining ring. The mounting plate is vertically slidably disposed inside the air storage cylinder. Multiple sets of compression springs are equidistantly arranged in a circular pattern at the bottom of the mounting plate. A piston is connected to the bottom end of each set of compression springs. The bottom of the piston abuts against a retaining ring. The retaining ring is disposed inside the air storage cylinder and is positioned above the second air supply pipe and the exhaust pipe.

[0012] Preferably, the pressurization assembly further includes an electric actuator, which is installed on the top wall inside the gas storage tank, and the output end of the electric actuator is connected to the mounting plate.

[0013] Preferably, the inner wall of the retaining ring is provided with a strip plate, and a first button is provided on the strip plate to abut against the piston. The first button is used to control the electric valve to close the drain port and the second check valve to close the backflush pipe. A pressing column is provided on the top of the piston, and a second button corresponding to the pressing column is connected to the bottom of the mounting plate. The second button is used to control the electric valve to open the drain port and the second check valve to open the backflush pipe.

[0014] Preferably, a mounting groove is provided at the center of the end face where the bottom cover connects to the motor, and a sealing ring is provided on the inner side of the mounting groove.

[0015] Preferably, the end face where the bottom cover connects to the motor is provided with multiple sets of protrusions at equal intervals around the circumference, and the side of the motor relative to the bottom cover is provided with multiple sets of grooves at equal intervals around the circumference, with the multiple sets of grooves corresponding to the multiple sets of protrusions.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention uses a linkage mechanism of a diaphragm cup and a steel needle to replace the solenoid valve. The motor drives the eccentric wheel to drive the diaphragm cup support to reciprocate. During the movement, the pull cup is pulled and deformed, changing the size of the pump body chamber, thereby realizing air extraction and exhaust. This effectively controls the working noise, meets the needs of sensitive scenarios, and improves the air extraction rate, meeting the stringent requirements of high-end home appliances for rapid low-oxygen preservation. The pump body adopts a modular structure composed of a bottom cover, a middle cover, and an end cover, integrating core components such as the motor, diaphragm cup, and pull cup together. Compared with the traditional solenoid valve, the volume is effectively reduced, improving the space utilization during operation. 2. This invention features a filter cylinder, an air storage cylinder, and a backflush pipe. The filter cylinder contains a filter element that filters impurities in the pumped gas. When impurities accumulate on the surface of the filter element, causing an increase in air intake resistance, the one-way valve of the exhaust pipe is closed to store air into the air storage cylinder. During the storage process, the piston rises and compresses the spring. After the piston reaches a specified height, it presses the second button via a pressing column. The second button opens the electric valve at the drain port at the bottom of the piston cylinder. The electric valve and the second one-way valve open the drain port and the backflush pipe, respectively, allowing the gas in the air storage cylinder to backflush the filter element through the backflush pipe. This blows the trapped dust, condensate, and other impurities into the open collection cylinder at the bottom of the filter cylinder. After cleaning, the piston returns to its original position, and the first button is pressed to close the drain port and the backflush pipe. This invention achieves the cleaning and maintenance of the vacuum pump and is suitable for scenarios such as refrigerators that require long-term continuous operation. 3. The pressurization assembly of the present invention is equipped with an electric actuator, which can adjust the height of the mounting plate. That is, when storing the same amount of gas, the compression degree of the piston on the pressure spring can be adjusted, thereby adjusting the cleaning force of the backflush pipe on the filter element. After a period of low-pressure backflush, high-pressure backflush can be switched to improve the cleaning effect on the filter element. Attached Figure Description

[0017] Figure 1 This is a front view structural diagram of the present invention; Figure 2 This is a partial cross-sectional view of the pump body of the present invention; Figure 3 This is a partial three-dimensional structural diagram of the pump body of the present invention; Figure 4 For the present invention Figure 3 A partial, upward-view diagram of the split structure in a backflush state; Figure 5 For the present invention Figure 3 Cross-sectional view of the structure in a non-backflush state; Figure 6 For the present invention Figure 5 A diagram of the structure viewed from below; Figure 7 For the present invention Figure 3 A cross-sectional view of the structure in a backflush state.

[0018] In the picture: 1. Pump body; 101. Bottom cover; 1011. Protrusion; 102. Middle cover; 103. End cover; 2. Motor; 201. Groove; 3. Eccentric wheel; 4. Leather cup bracket; 401. Guide hole; 5. Leather cup; 6. Steel needle; 7. Pull cup seat; 8. Pull cup; 9. First air supply pipe; 10. Second air supply pipe; 11. Filter cartridge; 1101. Drain outlet; 12. Backflush pipe; 13. Air storage tank; 14. Boosting assembly; 1401, mounting plate; 1402, compression spring; 1403, piston; 1404, retaining ring; 1405, electric actuator; 15, intake pipe; 16, filter element; 17, exhaust pipe; 18, first check valve; 19, second check valve; 20, open sludge collection cylinder; 21, electric valve; 22, strip plate; 23, first button; 24, pressing column; 25, second button; 26, sealing ring. Detailed Implementation

[0019] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0020] As attached Figure 1 To be continued Figure 7 As shown: This invention provides a vacuum pump and its application in a refrigerator, comprising a pump body 1, which is composed of a bottom cover 101, a middle cover 102, and an end cover 103. The middle cover 102 is located between the bottom cover 101 and the end cover 103. A motor 2 is disposed on the side of the bottom cover 101 opposite to the middle cover 102. The output shaft of the motor 2 extends to the inside of the bottom cover 101 and is connected to an eccentric wheel 3. A leather cup support 4, which is slidably connected to the bottom cover 101, is disposed on the outer edge of the eccentric wheel 3. A guide hole 401 is provided in the middle of the leather cup support 4. A leather cup 5 is disposed on the side of the leather cup support 4 opposite to the eccentric wheel 3, located inside the middle cover 102. A steel needle 6 is embedded in the middle of the leather cup 5. One end of the steel needle 6 extends... Extending to the inside of the guide hole 401, a pull cup seat 7 is provided on the side of the leather cup 5 away from the leather cup support 4. The pull cup seat 7 is located between the middle cover 102 and the end cover 103. A pull cup 8 is provided on the end face of the pull cup seat 7 away from the leather cup 5, located inside the end cover 103. The middle and top of the end face of the end cover 103 are respectively connected to the first air supply pipe 9 and the second air supply pipe 10. One end of the second air supply pipe 10 is connected to the air storage cylinder 13. One end of the first air supply pipe 9 is connected to the filter cylinder 11 located below the air storage cylinder 13. A backflush pipe 12 is connected between the filter cylinder 11 and the air storage cylinder 13. A pressurization component 14 is provided inside the air storage cylinder 13 for pressurizing when the backflush pipe 12 is in the conducting state.

[0021] It should be further noted that the pump body 1 is made of high-strength, corrosion-resistant ABS777 material, and the motor 2 is a DC brushless motor 2.

[0022] refer to Figure 2 and Figure 3 The bottom of the filter cylinder 11, which is away from the first air supply pipe 9, is connected to the air inlet pipe 15. Inside the filter cylinder 11, a filter element 16 is horizontally arranged, which is directly opposite to the backflush pipe 12. The filter element 16 is located between the air inlet pipe 15 and the first air supply pipe 9.

[0023] Specifically, during the gas extraction process, the gas is introduced into the filter cartridge 11 through the air inlet pipe 15, filtered by the filter element 16, and then introduced into the pump chamber through the first gas delivery pipe 9.

[0024] refer to Figure 3 The bottom of the gas storage cylinder 13, which is away from the second gas supply pipe 10, is connected to an exhaust pipe 17, which is positioned opposite the second gas supply pipe 10.

[0025] Specifically, when the gas storage cylinder 13 is not storing gas, the gas discharged from the pump chamber will be introduced into the gas storage cylinder 13 through the second gas delivery pipe 10 and discharged directly from the exhaust pipe 17.

[0026] refer to Figure 2 and Figure 3 The first air supply pipe 9, the second air supply pipe 10, the air inlet pipe 15, and the exhaust pipe 17 are all equipped with a first one-way valve 18, and the backflush pipe 12 is equipped with a second one-way valve 19.

[0027] Specifically, the first one-way valve 18 on the intake pipe 15 and the first gas delivery pipe 9 controls the gas to flow only in the direction of the pump chamber, and the first one-way valve 18 on the second gas delivery pipe 10 and the exhaust pipe 17 controls the gas to be discharged only from the direction of the pump chamber.

[0028] refer to Figure 4 The bottom end of the filter cylinder 11 is threadedly connected to an open sludge collection cylinder 20. The end face where the filter cylinder 11 connects to the open sludge collection cylinder 20 is provided with a drain port 1101. An electric valve 21 is installed inside the drain port 1101.

[0029] Specifically, the impurities backflushed from the filter element 16 can be discharged into the open collection cylinder 20 through the drain port 1101. The drain port 1101 can be closed during the operation of the vacuum pump through the electric valve 21 to prevent the impurities in the open collection cylinder 20 from being repeatedly adsorbed onto the filter element 16.

[0030] refer to Figure 5 , Figure 6 and Figure 7The booster assembly 14 includes a mounting plate 1401, a compression spring 1402, a piston 1403, and a retaining ring 1404. The mounting plate 1401 is vertically slidably disposed inside the air reservoir 13. Multiple sets of compression springs 1402 are circumferentially and equidistantly arranged at the bottom of the mounting plate 1401. The bottom ends of the multiple sets of compression springs 1402 are connected to the piston 1403. The bottom of the piston 1403 abuts against the retaining ring 1404. The retaining ring 1404 is disposed inside the air reservoir 13 and is located above the second air supply pipe 10 and the exhaust pipe 17.

[0031] Specifically, when the filter element 16 needs to be cleaned, the first one-way valve 18 on the exhaust pipe 17 is closed. The spring 1402 is compressed and stores elastic potential energy when the air tank 13 stores air. When backflushing, it releases energy to push the piston 1403 to accelerate the gas ejection, effectively removing deep blockages from the filter element 16.

[0032] refer to Figure 5 , Figure 6 and Figure 7 The booster assembly 14 also includes an electric actuator 1405, which is installed on the top wall inside the gas storage tank 13, and the output end of the electric actuator 1405 is connected to the mounting plate 1401.

[0033] Specifically, by adjusting the compression amount of the spring 1402 through the electric actuator 1405, the backflush force is graded under the same air storage capacity, thereby further improving the backflush effect on the filter element 16.

[0034] refer to Figure 6 and Figure 7 The inner wall of the retaining ring 1404 is provided with a strip plate 22. A first button 23 is provided on the strip plate 22 to abut against the piston 1403. The first button 23 is used to control the electric valve 21 to close the drain port 1101 and the second check valve 19 to close the backflush pipe 12. A pressing column 24 is provided on the top of the piston 1403. A second button 25 corresponding to the pressing column 24 is connected to the bottom of the mounting plate 1401. The second button 25 is used to control the electric valve 21 to open the drain port 1101 and the second check valve 19 to open the backflush pipe 12.

[0035] It should be further explained that the second button 25 is also used to control multiple first one-way valves 18 to close simultaneously, so that when the second button 25 is pressed, the gas in the air storage cylinder 13 can only be introduced into the inside of the filter cylinder 11 through the backflush pipe 12 to backflush the filter element 16. Similarly, the first button 23 is also used to control multiple first one-way valves 18 to open simultaneously, so as to ensure that the pump body 1 operates normally under vacuum after the cleaning mode ends.

[0036] Specifically, the gas storage cylinder 13 stores gas, and the piston 1403 drives the pressing column 24 to press the second button 25. The second button 25 triggers the opening action of the electric valve 21 and the second one-way valve 19, thereby opening the drain port 1101 and the backflush pipe 12 respectively. At this time, the gas in the storage cylinder is introduced into the filter cylinder 11 through the backflush pipe 12 to backflush the filter element 16. The impurities cleaned by backflush are introduced into the open collection cylinder 20 through the drain port 1101. After the backflush is completed, the piston 1403 moves downward to reset under the action of the compression spring 1402. When it resets to abut against the retaining ring 1404, the piston 1403 presses the first button 23. The first button 23 triggers the closing action of the electric valve 21 and the second one-way valve 19, closing the backflush pipe 12 and the drain port 1101.

[0037] refer to Figure 2 A mounting groove is provided at the center of the end face where the bottom cover 101 connects to the motor 2, and a sealing ring 26 is provided on the inner side of the mounting groove.

[0038] Specifically, the sealing ring 26 improves the tightness of the connection between the bottom cover 101 and the output shaft of the motor 2.

[0039] refer to Figure 2 The end face where the bottom cover 101 connects to the motor 2 is provided with multiple sets of protrusions 1011 at equal intervals around the circumference. The side of the motor 2 relative to the bottom cover 101 is provided with multiple sets of grooves 201 at equal intervals around the circumference. The multiple sets of grooves 201 are provided in correspondence with the multiple sets of protrusions 1011.

[0040] Specifically, the groove 201 and the protrusion 1011 are set on the assembly of the motor 2 and the bottom cover 101 to achieve precise positioning and prevent displacement, thus ensuring the stability during operation.

[0041] Working principle: When the vacuum pump is working, the motor 2 drives the eccentric wheel 3 to rotate, which in turn drives the cup 5 and the pull cup 8, which are linked to the cup support 4, to reciprocate and deform, causing the space in the pump body 1 chamber to change periodically. Gas enters the filter cartridge 11 through the inlet pipe 15, is filtered by the filter element 16, and then is unidirectionally introduced into the pump chamber through the first gas delivery pipe 9, and then unidirectionally discharged into the gas storage cylinder 13 through the second gas delivery pipe 10, and finally discharged from the exhaust pipe 17, realizing the pumping process. When the filter element 16 experiences an increase in inlet resistance due to the accumulation of impurities, the system closes the first one-way valve 18 of the exhaust pipe 17. The gas discharged from the pump chamber is pressurized in the gas storage cylinder 13. The piston 1403 rises with the increase of gas and squeezes the compression spring 1402. When the piston 1403 rises to the specified height, the second button 25 is triggered by pressing the pressure column 24. Simultaneously, the electric valve 21 and the second one-way valve 19 on the backflush pipe 12 are opened. The high-pressure gas in the gas storage cylinder 13 blows the filter element 16 in the reverse direction through the backflush pipe 12, blowing the trapped dust, condensate and other impurities down to the open collection cylinder 20. At the same time, the height of the mounting plate 1401 can be adjusted by the electric push rod 1405 to change the initial compression of the compression spring 1402 to control the backflush force in stages. After the backflush is completed, the piston 1403 is reset under the action of the compression spring 1402. When it comes into contact with the retaining ring 1404, the piston 1403 squeezes and triggers the first button 23, simultaneously closing the electric valve 21 and the second one-way valve 19 on the backflush pipe 12, restoring the vacuum pump to the pumping state, and finally achieving a low-noise, high-efficiency, and self-cleaning vacuum pumping cycle to meet the long-term low-oxygen preservation requirements of the refrigerator.

[0042] The embodiments of the present invention are given for the purposes of illustration and description. Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention, which is defined by the appended claims and their equivalents.

Claims

1. A vacuum pump and its application in a refrigerator, characterized in that, The pump body (1) consists of a bottom cover (101), a middle cover (102), and an end cover (103). The middle cover (102) is located between the bottom cover (101) and the end cover (103). A motor (2) is provided on the side of the bottom cover (101) away from the middle cover (102). The output shaft of the motor (2) extends to the inside of the bottom cover (101) and is connected to an eccentric wheel (3). The outer edge of the eccentric wheel (3) is in contact with a cup support (4) that is slidably connected to the bottom cover (101). A guide hole (401) is provided in the middle of the cup support (4). A cup (5) located inside the middle cover (102) is provided on the side of the cup support (4) away from the eccentric wheel (3). A steel needle (6) is embedded in the middle of the cup (5). One end of the steel needle (6) extends to the guide hole (401). Inside the leather cup (5), a pull cup seat (7) is provided on the side away from the leather cup support (4). The pull cup seat (7) is located between the middle cover (102) and the end cover (103). A pull cup (8) is provided on the end face of the pull cup seat (7) away from the leather cup (5) and located inside the end cover (103). The middle and top of the end face of the end cover (103) are respectively connected to the first air supply pipe (9) and the second air supply pipe (10). One end of the second air supply pipe (10) is connected to the air storage cylinder (13). One end of the first air supply pipe (9) is connected to the filter cylinder (11) located below the air storage cylinder (13). A backflush pipe (12) is connected between the filter cylinder (11) and the air storage cylinder (13). A pressurizing component (14) is provided inside the air storage cylinder (13) for pressurizing when the backflush pipe (12) is in the conducting state.

2. The vacuum pump as described in claim 1 and its application in a refrigerator, characterized in that: The bottom of the filter cylinder (11) facing away from the first air supply pipe (9) is connected to the air inlet pipe (15). Inside the filter cylinder (11), there is a filter element (16) that is directly opposite to the backflush pipe (12). The filter element (16) is located between the air inlet pipe (15) and the first air supply pipe (9).

3. The vacuum pump as described in claim 2 and its application in a refrigerator, characterized in that: The bottom of the gas storage cylinder (13) on the side away from the second gas supply pipe (10) is connected to an exhaust pipe (17), and the exhaust pipe (17) is set opposite to the second gas supply pipe (10).

4. The vacuum pump as described in claim 3 and its application in a refrigerator, characterized in that: The first gas supply pipe (9), the second gas supply pipe (10), the air inlet pipe (15), and the exhaust pipe (17) are all equipped with a first one-way valve (18), and the backflush pipe (12) is equipped with a second one-way valve (19).

5. The vacuum pump as described in claim 1 and its application in a refrigerator, characterized in that: The bottom end of the filter cylinder (11) is threadedly connected to an open sludge collection cylinder (20). The end face where the filter cylinder (11) connects to the open sludge collection cylinder (20) is provided with a drain port (1101). An electric valve (21) is installed inside the drain port (1101).

6. The vacuum pump as described in claim 5 and its application in a refrigerator, characterized in that: The booster assembly (14) includes a mounting plate (1401), a compression spring (1402), a piston (1403), and a retaining ring (1404). The mounting plate (1401) is vertically slidably disposed inside the air reservoir (13). Multiple sets of compression springs (1402) are circumferentially and equidistantly arranged at the bottom of the mounting plate (1401). The piston (1403) is connected to the bottom end of the multiple sets of compression springs (1402). The retaining ring (1404) abuts against the bottom of the piston (1403). The retaining ring (1404) is disposed inside the air reservoir (13) and is located above the second air supply pipe (10) and the exhaust pipe (17).

7. The vacuum pump as described in claim 6 and its application in a refrigerator, characterized in that: The booster assembly (14) also includes an electric actuator (1405), which is installed on the top wall inside the gas storage tank (13), and the output end of the electric actuator (1405) is connected to the mounting plate (1401).

8. The vacuum pump as described in claim 6 and its application in a refrigerator, characterized in that: The inner wall of the retaining ring (1404) is provided with a strip plate (22), and a first button (23) is provided on the strip plate (22) to abut against the piston (1403). The first button (23) is used to control the electric valve (21) to close the drain port (1101) and the second check valve (19) to close the backflush pipe (12). A pressing column (24) is provided on the top of the piston (1403), and a second button (25) corresponding to the pressing column (24) is connected to the bottom of the mounting plate (1401). The second button (25) is used to control the electric valve (21) to open the drain port (1101) and the second check valve (19) to open the backflush pipe (12).

9. The vacuum pump as described in claim 1 and its application in a refrigerator, characterized in that: A mounting groove is provided at the center of the end face where the bottom cover (101) connects to the motor (2), and a sealing ring (26) is provided on the inner side of the mounting groove.

10. The vacuum pump as described in claim 1 and its application in a refrigerator, characterized in that: The end face of the connection between the bottom cover (101) and the motor (2) is provided with multiple sets of protrusions (1011) at equal intervals in a circle. The side of the motor (2) relative to the bottom cover (101) is provided with multiple sets of grooves (201) at equal intervals in a circle. The multiple sets of grooves (201) are provided in correspondence with the multiple sets of protrusions (1011).

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