Acoustic wave motor convenient to maintain

Abstract

The utility model discloses a sound wave motor convenient to maintain, comprising a motor housing, the motor housing comprises an accommodating cavity, and two ends of the motor housing are respectively provided with a connecting end and an extending hole which are communicated with the accommodating cavity; the packaging end cover is detachably connected with the connecting end; the permanent magnet is arranged in the accommodating cavity; the rotor comprises an iron core part and a rotating shaft penetrating through the iron core part; one end of the rotating shaft extends out of the extending hole, and the other end of the rotating shaft is rotationally connected with the packaging end cover; a rotating interval is arranged between the permanent magnet and the iron core part; the connecting frame is arranged in the accommodating cavity and is attached to the inner wall of the motor shell; the limiting piece is connected with the rotating shaft, and the limiting piece is located between the extending hole and the iron core part; an amplitude limiting through groove is formed in the end, corresponding to the limiting piece, of the connecting frame and used for limiting rotation of the limiting piece and the rotor in the amplitude limiting through groove interval.

Description

Technical Field

[0001] This application relates to the field of motor device technology, specifically a sound wave motor that is easy to maintain. Background Technology

[0002] Currently, sonic motors typically employ high-cost servo motors, coupled with equally expensive and complex control circuit boards containing numerous electronic components, to achieve sweeping vibration output. Electric toothbrushes using this approach are also quite expensive. Patent application number 2024220586626 discloses a novel sonic motor that uses a limiting frame within the motor housing. The rotor magnet of the motor abuts against limiting protrusions on the limiting frame, thus limiting the rotor's rotation angle and achieving sweeping vibration output.

[0003] However, after prolonged use, the rotor magnets and limit protrusions experience hundreds of thousands of collisions, which can easily lead to the rotor magnets breaking or the limit protrusions wearing down, causing the motor to malfunction. In such cases, maintenance and repair require not only opening the motor housing but also disassembling components such as the power output shaft and magnetic guide frame, and removing the rotor and limit frame before the fault can be diagnosed and the corresponding parts replaced, impacting repair efficiency. Sometimes, the problem lies with the drive circuit board, resulting in wasted time and effort completely disassembling the motor to troubleshoot the problem.

[0004] Therefore, there is an urgent need to improve the structure of this acoustic motor to make it easier to repair and maintain. Utility Model Content

[0005] This utility model addresses the above-mentioned problems by proposing a sound wave motor that is easy to maintain, aiming to solve the technical problems in the background art.

[0006] To achieve the above objectives, this utility model provides an easy-to-maintain acoustic motor, comprising:

[0007] The motor housing includes a receiving cavity, and the two ends of the motor housing are respectively provided with a connecting end communicating with the receiving cavity and an extension hole;

[0008] A sealing end cap, wherein the sealing end cap is detachably connected to the connecting end;

[0009] A permanent magnet is disposed in the receiving cavity;

[0010] The rotor includes an iron core and a rotating shaft passing through the iron core; one end of the rotating shaft extends out of the extension hole, and the other end is rotatably connected to the encapsulation end cover; a rotational gap is provided between the permanent magnet and the iron core;

[0011] A limiting member is provided, which is connected to the rotating shaft and is located between the protruding hole and the iron core. The motor housing is provided with an observation slot corresponding to the end of the limiting member, which is used to restrict the rotation of the limiting member and the rotor within the observation slot area.

[0012] This utility model also provides an easy-to-maintain acoustic motor, characterized in that it includes:

[0013] The motor housing includes a receiving cavity, and the two ends of the motor housing are respectively provided with a connecting end communicating with the receiving cavity and an extension hole;

[0014] A sealing end cap, wherein the sealing end cap is detachably connected to the connecting end;

[0015] A permanent magnet is disposed in the receiving cavity;

[0016] The rotor includes an iron core and a rotating shaft passing through the iron core; one end of the rotating shaft extends out of the extension hole, and the other end is rotatably connected to the encapsulation end cover; a rotational gap is provided between the permanent magnet and the iron core;

[0017] A connecting frame is disposed in the receiving cavity and is set against the inner wall of the motor housing;

[0018] A limiting member is provided, which is connected to the rotating shaft and is located between the protruding hole and the iron core. The connecting frame is provided with a limiting through groove at the end of the limiting member to restrict the rotation of the limiting member and the rotor within the limiting through groove.

[0019] Furthermore, the connecting frame is a two-part frame structure, which is connected to each other and holds and positions the permanent magnet.

[0020] Furthermore, there are two limiting through slots, which are symmetrically arranged; the two ends of the limiting member extend into the two limiting through slots respectively.

[0021] Furthermore, the included angle formed by connecting the two sides of the limiting through groove with the axis of the rotating shaft is 27°~31°.

[0022] Furthermore, it includes a first bearing, the inner ring of which is sleeved and connected to the outer wall of the shaft, and the outer ring is connected to the protruding hole.

[0023] Furthermore, it includes a second bearing, the inner ring of which is sleeved and connected to the outer wall of the shaft, and the outer ring is connected to the encapsulation end cap.

[0024] Furthermore, the rotating shaft includes a base shaft and a transition shaft; the iron core portion is sleeved and connected to the base shaft as a whole; the inner ring of the first bearing is sleeved and connected to the transition shaft; one end of the transition shaft extends into the receiving cavity and is sleeved and connected to the base shaft; the limiting member is disposed between the end of the base shaft and the iron core portion, and the limiting member is interference-fitted with the outer wall of the base shaft to limit the axial position of the base shaft.

[0025] Furthermore, the limiting component is made of metal, and the connecting frame is made of plastic.

[0026] This utility model also provides an easy-to-maintain acoustic motor, comprising:

[0027] The motor housing includes a receiving cavity, and the two ends of the motor housing are respectively provided with a connecting end communicating with the receiving cavity and an extension hole;

[0028] The encapsulation end cap is detachably connected to the connection end; the end face of the encapsulation end cap away from the motor housing is provided with a limiting groove;

[0029] A permanent magnet is disposed in the receiving cavity;

[0030] The rotor includes an iron core and a rotating shaft passing through the iron core; one end of the rotating shaft extends out of the extension hole, and the other end is rotatably connected to the encapsulation end cover and extends into the limiting groove; a rotational gap is provided between the permanent magnet and the iron core;

[0031] A limiting member is provided in the limiting groove and is connected to the rotating shaft. The limiting groove is used to restrict the rotation of the limiting member and the rotor within the limiting groove range.

[0032] Compared with existing technologies, this utility model provides an easy-to-maintain acoustic motor. Maintenance personnel can observe the quality of the structure that plays a key role in limiting the rotational amplitude without disassembling or completely disassembling the motor, and determine whether it is necessary to disconnect the encapsulated end cover from the motor housing for replacement of corresponding components. This significantly improves maintenance efficiency and makes repair and maintenance easier. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of a maintenance-friendly acoustic motor structure according to this application.

[0034] Figure 2 This is an exploded view of the structure of an embodiment of an easy-to-maintain acoustic motor according to this application.

[0035] Figure 3 This is an exploded view of the structure of a second embodiment of an easy-to-maintain acoustic motor according to this application.

[0036] Figure 4 This is a further structural exploded view of Embodiment 2 of an easy-to-maintain acoustic motor according to this application.

[0037] Figure 5 This is a schematic diagram of the encapsulation end cap and limiting component structure of a third embodiment of an easy-to-maintain acoustic motor according to this application.

[0038] Figure 6 This is an exploded view of the encapsulation end cap and limiting component structure of a third embodiment of an easy-to-maintain acoustic motor according to this application.

[0039] Figure 7 This is a schematic diagram of the connecting frame structure of a second embodiment of an acoustic motor that is easy to maintain, as described in this application.

[0040] Figure 8 This is a side view of the connecting frame of a second embodiment of an easy-to-maintain acoustic motor according to this application.

[0041] Figure 9 This is an exploded view of the structure of a second embodiment of an easy-to-maintain acoustic motor according to this application.

[0042] The reference numerals in the figure are as follows: 1. Motor housing; 120. Connecting end; 130. Protrusion hole; 140. Observation slot; 2. Encapsulation end cover; 210. Limiting slot; 3. Permanent magnet; 4. Rotor; 410. Iron core; 420. Rotating shaft; 421. Base shaft; 422. Adapter shaft; 5. Limiting component; 6. Connecting frame; 610. Limiting slot; 7. Included angle; 8. First bearing; 9. Second bearing. Detailed Implementation

[0043] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present utility model, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the protection scope of the present utility model. It is understood that the accompanying drawings are provided for reference and illustration only and are not intended to limit the present utility model. The connection relationships shown in the drawings are only for clear description and do not limit the connection method.

[0044] It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component, or there may be an intervening component. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be noted that, unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly, for example, as a fixed connection, a detachable connection, or an integral connection; as a mechanical connection or an electrical connection; or as a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention.

[0045] It should also be noted that in the description of this utility model, the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0046] Example 1

[0047] Please refer to Figure 2 This embodiment provides an easy-to-maintain acoustic motor, including:

[0048] The motor housing 1 includes a receiving cavity, and the motor housing 1 has a connecting end 120 and an extension hole 130 at both ends that communicate with the receiving cavity;

[0049] Encapsulation end cap 2, which is detachably connected to the connection end 120;

[0050] Permanent magnet 3, the permanent magnet 3 being disposed in the receiving cavity;

[0051] The rotor 4 includes an iron core 410 and a rotating shaft 420 passing through the iron core 410; one end of the rotating shaft 420 extends out of the extension hole 130, and the other end is rotatably connected to the encapsulation end cover 2; a rotational gap is provided between the permanent magnet 3 and the iron core 410.

[0052] The limiting member 5 is connected to the rotating shaft 420 and is located between the protrusion hole 130 and the iron core part 410; the motor housing 1 is provided with an observation groove 140 corresponding to the end of the limiting member 5, which is used to restrict the limiting member 5 and the rotor 4 from rotating within the observation groove 140.

[0053] By opening an observation slot 140 in the motor housing 1 and connecting a limiting member 5 to the rotating shaft 420 of the rotor 4,

[0054] The inner wall of the motor housing 1 can be provided with a limiting structure that corresponds to and matches the limiting member 5. Alternatively, the inner cavity of the motor housing 1 can be like that of existing motors, with a limiting frame set inside the motor housing. The limiting member 5 and the limiting protrusions on the limiting frame abut against each other to limit the rotor rotation angle and achieve sweeping output. Alternatively, an advanced control circuit board can be used to control the rotation frequency and amplitude of the rotor 4.

[0055] By observing the through-slot 140, maintenance personnel can assess the structural quality of the limiting component 5 without disassembling the motor, determining whether it is necessary to disconnect the encapsulation end cover 2 from the motor housing 1 and replace the limiting component 5 or the corresponding limiting structure of the motor housing 1. This significantly improves maintenance efficiency and makes repairs easier.

[0056] Of course, brushes or conductive connecting components, similar to those in a conventional motor, can be fitted at the end cap 2 of the package for electrical connection with the coil on the core 410. This aspect of the structure is not the focus of this application's innovation and will not be elaborated upon here.

[0057] Example 2

[0058] Please refer to Figure 1 and Figure 3 , Figure 4 , Figure 7 and Figure 8 This utility model also provides an easy-to-maintain acoustic motor, comprising:

[0059] The motor housing 1 includes a receiving cavity, and the motor housing 1 has a connecting end 120 and an extension hole 130 at both ends that communicate with the receiving cavity;

[0060] Encapsulation end cap 2, which is detachably connected to the connection end 120;

[0061] Permanent magnet 3, the permanent magnet 3 being disposed in the receiving cavity;

[0062] The rotor 4 includes an iron core 410 and a rotating shaft 420 passing through the iron core 410; one end of the rotating shaft 420 extends out of the extension hole 130, and the other end is rotatably connected to the encapsulation end cover 2; a rotational gap is provided between the permanent magnet 3 and the iron core 410.

[0063] Connecting frame 6 is disposed in the receiving cavity and is set against the inner wall of the motor housing 1;

[0064] The limiting member 5 is connected to the rotating shaft 420 and is located between the protrusion hole 130 and the iron core part 410; the connecting frame 6 is provided with a limiting groove 610 corresponding to the end of the limiting member 5, which is used to limit the rotation of the limiting member 5 and the rotor 4 within the limiting groove 610.

[0065] In Embodiment 1 and Embodiment 3, the observation channel 140 and the limiting channel 210 are exposed to the outside world. Some small debris in the outside world may enter the receiving cavity through the observation channel 140 or fill the limiting channel 210, causing the motor in Embodiment 1 and Embodiment 3 to malfunction. The motor in these two embodiments is not suitable for use in an exposed environment, but is suitable for use in a relatively closed housing.

[0066] In this embodiment, embodiment two is the optimal embodiment because it interacts with the limiting member 5, restricting the rotation of the limiting member 5 and the rotor 4 within the limiting through groove 610. The carrier connecting frame 6 of the limiting through groove 610 is located in the receiving cavity. In this way, small external debris will not easily enter the receiving cavity and clog or affect the limiting through groove 610.

[0067] When maintenance personnel perform detailed maintenance, they only need to disconnect the motor housing 1 from the encapsulation end cover 2 to easily observe whether the limiting through slot 610 and the limiting component 5 on the connecting frame 6 are intact, and then they can quickly carry out the inspection work.

[0068] Please refer to Figure 3 and Figure 4 , Figure 7 , Figure 9 The connecting frame 6 is a two-part frame structure, which is connected to each other and holds and positions the permanent magnet 3.

[0069] During assembly, the connecting frame 6 of half the frame is first installed into the inner cavity of the motor housing 1. Then, the strip-shaped permanent magnet 3 is inserted into the connecting frame 6 of the half frame for pre-positioning. Then, the rotor 4 assembly with limit piece 5 is connected to the motor housing 1. Finally, the connecting frame 6 of half the frame is installed into the inner cavity of the motor housing 1. At the same time, the remaining structure of the permanent magnet 3 is clamped and positioned. Finally, the end cover 2 is sealed and connected to the motor housing 1.

[0070] To avoid the situation where the connecting frame 6 is only half of the frame structure, the permanent magnet 3 is not sufficiently fixed and is prone to tilting.

[0071] The connecting bracket 6 can also support the motor housing 1 and strengthen its structural strength, serving three purposes in one, demonstrating ingenious design.

[0072] Please refer to Figure 3 and Figure 4 , Figure 7 The number of limiting through slots 610 is two, symmetrically arranged; the two ends of the limiting member 5 extend into the two limiting through slots 610 respectively.

[0073] This configuration enhances the stability of motor operation, improves the stability of motor sweeping vibration output, and extends the service life of components.

[0074] Please refer to Figure 7 The included angle 7 formed by connecting the two sides of the limiting through groove 610 with the axis of the rotating shaft 420 is 27°~31°.

[0075] Please refer to Figure 3 and Figure 4 It includes a first bearing 8, the inner ring of the first bearing 8 is sleeved and connected to the outer wall of the rotating shaft 420, and the outer ring is connected to the protrusion hole 130.

[0076] Please refer to Figure 3 and Figure 4 It includes a second bearing 9, the inner ring of which is sleeved and connected to the outer wall of the rotating shaft 420, and the outer ring is connected to the encapsulation end cap 2.

[0077] Please refer to Figure 3 and Figure 4 The rotating shaft 420 includes a base shaft 421 and a transition shaft 422; the iron core portion 410 is sleeved and connected to the base shaft 421 as a whole; the inner ring of the first bearing 8 is sleeved and connected to the transition shaft 422; one end of the transition shaft 422 extends into the receiving cavity and is sleeved and connected to the base shaft 421; the limiting member 5 is provided between the end of the base shaft 421 and the iron core portion 410, and the limiting member 5 is interference-fitted to the outer wall of the base shaft 421 to limit the axial position of the base shaft 421.

[0078] The outer diameter of the adapter shaft 422 is larger than the outer diameter of the base shaft 421. The end face of the adapter shaft 422 is flush with the end face of the first bearing 8. Since the iron core 410 and the base shaft 421 are connected as a whole, and the limiting member 5 and the base shaft 421 are also connected as a whole, the positional relationship between the limiting member 5 and the base shaft 421 is first determined. Then, the position of the limiting member 5 is limited by the end face of the adapter shaft 422, the end face of the first bearing 8, and the iron core 410. This naturally determines the position of the base shaft 421 and the iron core 410, thereby limiting the axial position of the base shaft 421. This improves the machining accuracy of the motor and ensures that the quality of the finished product is consistently high.

[0079] The base shaft 421, also known as the inner shaft, is mainly located inside the motor housing 1 and is used to connect the iron core 410. When the limiting member 5 connects to the base shaft 421, it uses force to force the base shaft 421 through the inner hole of the limiting member 5, so that the limiting member 5 stops at a designated position in the length direction of the base shaft 421. After the connection is completed, since the two are in an interference fit relationship, they will not easily move relative to each other. Then, the adapter shaft 422 can be used as a reference for the limiting member 5. One end of the adapter shaft 422 is sleeved on the base shaft 421 and abuts against the limiting member 5, thus completing the precise positioning connection.

[0080] Preferably, the limiting member 5 is made of metal, and the connecting frame 6 is made of plastic.

[0081] The limiting component 5 can be made of low-cost, high-strength materials such as aluminum alloy or iron alloy. However, if the connecting frame 6 is made of plastic, it is more likely to be damaged after hundreds of thousands of relative impacts with the limiting component 5, requiring only replacement. Furthermore, plastic is easier to recycle, resulting in lower recycling costs.

[0082] This technology improves upon the shortcomings of existing technologies, which involve the rotor magnet impacting the limiting protrusion on the limiting frame, resulting in the rotor magnet breaking or the limiting protrusion wearing down, leading to high replacement costs and high costs for recycling broken magnets.

[0083] Example 3

[0084] Please refer to Figure 5 and Figure 6 This utility model also provides an easy-to-maintain acoustic motor, comprising:

[0085] The motor housing 1 includes a receiving cavity, and the motor housing 1 has a connecting end 120 and an extension hole 130 at both ends that communicate with the receiving cavity;

[0086] The encapsulation end cover 2 is detachably connected to the connection end 120; the end face of the encapsulation end cover 2 away from the motor housing 1 is provided with a limiting groove 210;

[0087] Permanent magnet 3, the permanent magnet 3 being disposed in the receiving cavity;

[0088] The rotor 4 includes an iron core 410 and a rotating shaft 420 passing through the iron core 410; one end of the rotating shaft 420 extends out of the extension hole 130, and the other end is rotatably connected to the encapsulation end cover 2 and extends into the limiting groove 210; a rotational gap is provided between the permanent magnet 3 and the iron core 410.

[0089] The limiting member 5 is disposed in the limiting groove 210 and is connected to the rotating shaft 420. The limiting groove 210 is used to restrict the limiting member 5 and the rotor 4 from rotating within the limiting groove 210.

[0090] Preferably, the rotating shaft 420 extending into the limiting groove 210 has a semi-circular cross-section, so that the limiting member 5 and the rotating shaft 420 are glued together, the connection is stable and not easy to slip.

[0091] Both the limiting component 5 and the limiting groove 210 on the encapsulation end cover 2 are exposed to the outside and are easy to observe directly. Therefore, when performing maintenance, it is not necessary to disassemble the motor to determine the fault location of either of them, which is convenient and quick.

[0092] In the specification and claims of this application, the terms "comprising / including" and "having / including" and variations thereof are used to specify the presence of the stated features, values, steps or components, but do not exclude the presence or addition of one or more other features, values, steps, components or combinations thereof.

[0093] Some features of this invention are described in different embodiments for clarity; however, these features may also be described in combination in a single embodiment. Conversely, some features of this invention are described only in a single embodiment for brevity; however, these features may also be described individually or in any suitable combination in different embodiments.

[0094] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A maintenance-friendly acoustic motor, characterized in that, include: The motor housing includes a receiving cavity, and the two ends of the motor housing are respectively provided with a connecting end communicating with the receiving cavity and an extension hole; A sealing end cap, wherein the sealing end cap is detachably connected to the connecting end; A permanent magnet is disposed in the receiving cavity; The rotor includes an iron core and a rotating shaft passing through the iron core; one end of the rotating shaft extends out of the extension hole, and the other end is rotatably connected to the encapsulation end cover; a rotational gap is provided between the permanent magnet and the iron core; A limiting member is provided, which is connected to the rotating shaft and is located between the protruding hole and the iron core; the motor housing is provided with an observation through groove corresponding to the end of the limiting member.

2. A maintenance-friendly acoustic motor, characterized in that, include: The motor housing includes a receiving cavity, and the two ends of the motor housing are respectively provided with a connecting end communicating with the receiving cavity and an extension hole; A sealing end cap, wherein the sealing end cap is detachably connected to the connecting end; A permanent magnet, wherein the permanent magnet is disposed in the receiving cavity; The rotor includes an iron core and a rotating shaft passing through the iron core; one end of the rotating shaft extends out of the extension hole, and the other end is rotatably connected to the encapsulation end cover; a rotational gap is provided between the permanent magnet and the iron core; A connecting frame is disposed in the receiving cavity and is set against the inner wall of the motor housing; A limiting member is provided, which is connected to the rotating shaft and is located between the protruding hole and the iron core. The connecting frame is provided with a limiting through groove at the end of the limiting member to restrict the rotation of the limiting member and the rotor within the limiting through groove.

3. The easy-to-maintain acoustic motor according to claim 2, characterized in that, The connecting frame consists of two half-frame structures, which are connected together and hold and position the permanent magnet.

4. The easy-to-maintain acoustic motor according to claim 2, characterized in that, The limiting through slots are two in number and are arranged symmetrically; the two ends of the limiting member extend into the two limiting through slots respectively.

5. The easy-to-maintain acoustic motor according to claim 2, characterized in that, The included angle between the two sides of the limiting through groove and the axis of the rotating shaft is 27°~31°.

6. The easy-to-maintain acoustic motor according to claim 2, characterized in that, It includes a first bearing, the inner ring of which is sleeved and connected to the outer wall of the shaft, and the outer ring is connected to the protruding hole.

7. The easy-to-maintain acoustic motor according to claim 2, characterized in that, It includes a second bearing, the inner ring of which is sleeved and connected to the outer wall of the shaft, and the outer ring is connected to the encapsulation end cap.

8. The easy-to-maintain acoustic motor according to claim 6, characterized in that, The rotating shaft includes a base shaft and a transition shaft; the iron core portion is sleeved and connected to the base shaft as a whole; the inner ring of the first bearing is sleeved and connected to the transition shaft; one end of the transition shaft extends into the receiving cavity and is sleeved and connected to the base shaft; the limiting member is provided between the end of the base shaft and the iron core portion, and the limiting member is interference-fitted with the outer wall of the base shaft to limit the axial position of the base shaft.

9. A maintenance-friendly acoustic motor according to claim 2, characterized in that, The limiting component is made of metal, and the connecting frame is made of plastic.

10. A maintenance-friendly acoustic motor, characterized in that, include: The motor housing includes a receiving cavity, and the two ends of the motor housing are respectively provided with a connecting end communicating with the receiving cavity and an extension hole; The encapsulation end cap is detachably connected to the connection end; the end face of the encapsulation end cap away from the motor housing is provided with a limiting groove; A permanent magnet is disposed in the receiving cavity; The rotor includes an iron core and a rotating shaft passing through the iron core; one end of the rotating shaft extends out of the extension hole, and the other end is rotatably connected to the encapsulation end cover and extends into the limiting groove; a rotational gap is provided between the permanent magnet and the iron core; A limiting member is provided in the limiting groove and is connected to the rotating shaft. The limiting groove is used to restrict the rotation of the limiting member and the rotor within the limiting groove range.

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