Position angle measuring assembly for motor rotor, and electric toothbrush

Abstract

Disclosed in the present application are a position angle measuring assembly for a motor rotor, and an electric toothbrush. The position angle measuring assembly for a motor rotor comprises: a limiting cover, which is provided with an accommodation cavity having an opening; a cover body, which covers the opening; a bearing, which is embedded in the accommodation cavity, two ends of the outer ring of the bearing correspondingly abutting against the limiting cover and the cover body, and the limiting cover and / or the cover body being provided with a clearance hole corresponding to the inner ring of the bearing; a motor shaft, which extends into the accommodation cavity through the clearance hole and is fixed to the inner ring of the bearing; a first magnet, which is fixed relative to the motor shaft and is capable of rotating along with the motor shaft; and a circuit board, which is provided with a second magnet, the second magnet and the first magnet being arranged opposite to each other. The configuration can improve the accuracy of position measurement results.

Description

Motor rotor position angle detection component and electric toothbrush Technical Field

[0001] The present application relates to the technical field of electric toothbrushes, and in particular to a position angle detection component of a motor rotor and an electric toothbrush. Background Art

[0002] To detect the position of the motor shaft, magnets are placed on the motor shaft and the circuit board. The rotation angle of the motor shaft is determined by sensing changes in the magnetic poles. However, in traditional solutions, the motor shaft is prone to wobble at high speeds. This inherent wobble can cause the magnets on the motor shaft and the circuit board to misalign at their initial positions, leading to inaccurate detection results.

[0003] Utility Model Content

[0004] The main purpose of this application is to propose a motor rotor position angle detection component and an electric toothbrush, aiming to keep the relative position between the first magnet and the second magnet stable, thereby improving the accuracy of the position detection result.

[0005] To achieve the above objectives, the present application proposes a motor rotor position angle detection component, comprising:

[0006] The limiting cover has an open accommodating cavity;

[0007] a cover body, covering the opening;

[0008] A bearing is embedded in the accommodating cavity, with two ends of the outer ring of the bearing correspondingly abutting against the limiting cover and the cover body, and the limiting cover and / or the cover body are provided with clearance holes corresponding to the inner ring of the bearing;

[0009] The motor shaft extends from the clearance hole into the accommodating cavity and is fixed to the inner ring of the bearing;

[0010] A first magnet is fixed relative to the motor shaft and can rotate with the motor shaft; and

[0011] The circuit board is provided with a second magnet, and the second magnet is arranged opposite to the first magnet.

[0012] Optionally, a plurality of limiting protrusions are provided on a side of the limiting cover facing the cover body, and the plurality of limiting protrusions are spaced around the opening;

[0013] The cover body is provided with a plurality of limiting holes, and the plurality of limiting holes are plugged into the plurality of limiting protrusions in a one-to-one correspondence.

[0014] Optionally, the cover body is provided with a plurality of welding protrusions, the plurality of welding protrusions are distributed at intervals around the opening, and the welding protrusions are welded to the limiting cover.

[0015] Optionally, the position angle detection component of the motor rotor also includes a mounting seat, the mounting seat forms a storage space, the limit cover and the cover body are located in the storage space, one of the limit cover and the cover body is fixed to the mounting seat; the circuit board is fixed to the mounting seat.

[0016] Optionally, the limiting cover includes a cover body and a mounting flange, the cover body forms the accommodating cavity, the mounting flange is arranged around the opening and bent outward relative to the cover body, and the cover body is in contact with the mounting flange;

[0017] A first step surface is formed on the inner wall of the mounting seat, and the mounting flange is overlapped and fixed on the first step surface.

[0018] Optionally, a second step surface is further formed on the inner wall of the mounting seat, and the circuit board is overlapped and fixed on the second step surface.

[0019] Optionally, the inner wall of the mounting seat is provided with a positioning boss, a surface of the positioning boss constitutes at least a part of the second step surface, the positioning boss is provided with a positioning column and a fixing hole, the circuit board is provided with a positioning hole and a connecting hole, the positioning column is plugged into the positioning hole, and a fastener is passed through the fixing hole and the connecting hole to fix the circuit board and the positioning boss.

[0020] Optionally, the circuit board is located at one end of the motor shaft and has a first surface facing the first magnet, the second magnet is fixed to the first surface, and the vertical distance between the first surface and the first magnet is greater than or equal to 0.1 mm and less than or equal to 0.4 mm.

[0021] Optionally, the circuit board is provided with two second magnets, the two second magnets are distributed on the same base circle, and the central angle of the two second magnets is 90°, and the base circle is coaxial with the motor shaft;

[0022] The first magnet is annular and is arranged around the motor shaft. The first magnet includes a first semicircle and a second semicircle distributed in half. The magnetic poles of the first semicircle and the second semicircle are in opposite directions.

[0023] Optionally, the position angle detection assembly of the motor rotor further includes a tray, the tray is provided with an avoidance hole for the motor shaft to pass through, the tray is welded and fixed to the motor shaft, the tray is formed with a mounting groove, and the first magnet is embedded in the mounting groove and fixed thereto.

[0024] An embodiment of the present application also proposes an electric toothbrush, comprising: a handle housing, a brush head, and a position angle detection component of a motor rotor; the detection component is installed in the handle housing, the brush head is located outside the handle housing and is fixed to the motor shaft of the motor rotor position angle detection component.

[0025] The technical solution in the embodiment of the present application adopts the above-mentioned structure, whereby one end of the outer ring of the bearing is abutted and restrained by the limit cover, and the other end of the outer ring is abutted and restrained by the cover body. That is, the outer ring of the bearing is clamped by the limit cover and the cover body, thereby preventing the outer ring from moving in the axial direction. The bearing is embedded in the accommodating cavity, thereby preventing the bearing from shaking in the radial direction relative to the limit structure. Thus, through the improvement of the mounting structure, the limit cover and the cover body work together to ensure the position accuracy of the bearing. When the motor shaft is fixed to the inner ring of the bearing, the outer ring can prevent the motor shaft from moving. As a result, the first magnet fixed to the motor shaft moves substantially along a preset trajectory as the motor shaft rotates, and the relative position between the first magnet and the second magnet is guaranteed and maintained stable, thereby avoiding inaccurate position detection results. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0027] FIG1 is a schematic structural diagram of a portion of the structure of an electric toothbrush according to an embodiment of the present application;

[0028] FIG2 is a plan view of the electric toothbrush in FIG1 ;

[0029] FIG3 is a schematic cross-sectional view of the electric toothbrush along line AA in FIG2 ;

[0030] FIG4 is an enlarged schematic diagram of point B in FIG3 ;

[0031] 5 and 6 are schematic structural diagrams of the position angle detection assembly of the motor rotor in FIG1 at different angles;

[0032] 7 and 8 are exploded schematic diagrams of the position angle detection assembly of the motor rotor in FIG. 5 at different angles;

[0033] FIG9 is a plan view of the circuit board in FIG8 ;

[0034] FIG10 is a schematic plan view of the first magnet in FIG8 .

[0035] Description of Figure Numbers: DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0037] It should be noted that, in the description of this application, if the terms "first", "second", etc. appear, "first" and "second" are only used to facilitate the description of different components or names, and cannot be understood as indicating or implying a sequential relationship, relative importance, or implicitly indicating the number of technical features indicated. Therefore, the features specified as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, if "and / or" appears in the full text, its meaning is to include three parallel solutions. Taking "A and / or B as an example", it includes Solution A, Solution B, or solutions that meet both A and B.

[0038] Electric toothbrushes rely on the rotation of the motor shaft to drive the brush head to swing back and forth and vibrate. Therefore, it is necessary to detect the rotation angle of the motor shaft. This not only prevents the motor shaft from rotating at an excessive angle, but also controls its reverse rotation after it is known to have rotated to a predetermined position, thereby achieving back and forth swinging or vibration.

[0039] In related technologies, magnets are placed on the motor shaft and the circuit board, respectively, to detect the rotation angle of the motor shaft by sensing the change in magnetic poles. The relative position of the magnets on the motor shaft and the circuit board directly affects the accuracy of the detection results.

[0040] Please refer to Figure 9. In some embodiments of the present application, the circuit board 60 is provided with two second magnets 64. The two second magnets 64 are distributed on the same base circle O (the base circle O refers to an imaginary circle), and the central angle α of the two second magnets 64 is 90°. The base circle O is coaxial with the motor shaft 40 (Figure 1). The motor shaft 40 is fixed with a first magnet 50. The first magnet 50 is annular and is arranged around the motor shaft 40. As shown in Figure 10, the first magnet 50 includes a first semicircle 51 and a second semicircle 52 distributed in half. The magnetic poles of the first semicircle 51 and the second semicircle 52 are in opposite directions. Through such a configuration, when the motor shaft 40 rotates, sine and cosine signals are generated between the two second magnets 64 and the first magnet 50. Therefore, the rotation angle and direction of the motor shaft 40 can be determined based on the sine and cosine signals, thereby completing the sweeping and vibration of the electric toothbrush without a mechanical limit structure (sweeping and vibration, sweeping refers to a back and forth swing at a larger angle, and vibration refers to a vibration at a smaller angle).

[0041] If the first magnet 50 and the second magnet 64 are installed in a positional misalignment, the sine and cosine signals may exhibit amplitude and phase deviations, significantly interfering with position determination. Furthermore, in other embodiments, other types of magnets may be employed, such as a first magnet 50 and a second magnet 64 to detect the rotation angle and direction of the motor shaft 40, thereby determining the position angle of the motor rotor. Similarly, if the first magnet 50 and the second magnet 64 are installed in a positional misalignment, the magnetic pole signals may also exhibit misalignment.

[0042] To address this, in the embodiment of the present application, the bearing is limited to reduce or avoid the movement of the motor shaft 40, thereby reducing the assembly error and reducing or avoiding the deviation value of the relative position of the first magnet 50 and the second magnet 64.

[0043] With reference to Figures 1 to 8, an embodiment of the present application provides a motor rotor position angle detection assembly, comprising: a stop cover 10, a cover 20, a bearing 30, a motor shaft 40, a first magnet 50, and a circuit board 60. The stop cover 10 has a receiving chamber 11 with an opening 12; the cover 20 covers the opening 12; the bearing 30 is embedded in the receiving chamber 11, with the ends of the outer ring of the bearing 30 correspondingly abutting the stop cover 10 and the cover 20. The stop cover 10 and / or the cover 20 are provided with clearance holes 13 / 21 corresponding to the inner ring of the bearing 30; the motor shaft 40 extends into the receiving chamber 11 through the clearance holes 13 / 21 and is fixed to the inner ring of the bearing 30; the first magnet 50 is fixed relative to the motor shaft 40 and can rotate with the motor shaft 40; and the circuit board 60 is provided with a second magnet 64, which is arranged opposite to the first magnet 50.

[0044] By adopting the above structure, one end of the outer ring of the bearing 30 is restrained by the retaining cover 10, and the other end of the outer ring is restrained by the cover 20. That is, the outer ring of the bearing 30 is jointly clamped by the retaining cover 10 and the cover 20, preventing axial movement of the outer ring. The bearing 30 is embedded in the accommodating cavity 11, preventing radial movement of the bearing 30 relative to the retaining structure. Thus, the retaining cover 10 and the cover 20 work together to ensure the positional accuracy of the bearing 30. When the motor shaft 40 is fixed to the inner ring of the bearing 30, the outer ring's position prevents movement of the motor shaft 40. As a result, the first magnet 50 fixed to the motor shaft 40 moves substantially along a predetermined trajectory as the motor shaft 40 rotates. The relative position between the first magnet 50 and the second magnet 64 is guaranteed and maintained stable, thereby preventing inaccurate position detection results.

[0045] Furthermore, the position angle detection assembly of the motor rotor also includes a mounting base 70, and the mounting base 70 forms a storage space 71. The limiting cover 10 and the cover body 20 are located in the storage space 71, and one of the limiting cover 10 and the cover body 20 is fixed to the mounting base 70; the circuit board 60 is fixed to the mounting base 70. For better explanation, the structure formed by the limiting cover 10 and the cover body 20 is defined as a limiting structure. In the embodiment of the present application, by fixing the limiting structure and the circuit board 60 to the mounting base 70 at the same time, the basic objects to which the two are fixed are consistent, thereby reducing the assembly error and reducing or avoiding the deviation value of the relative position of the first magnet 50 and the second magnet 64.

[0046] By adopting the above structure, the following effects are achieved:

[0047] First, the circuit board 60 and the limiting structure are respectively fixed to the mounting base 70, and the fixing base is the same as the mounting base 70. Therefore, there are fewer assembly links in the middle, so the total error after the assembly errors generated by each assembly link are superimposed is small, and the relative position between the circuit board 60 and the limiting structure can be guaranteed;

[0048] Second, one end of the outer ring of the bearing 30 is held in position by the retaining cover 10, while the other end is held in position by the cover 20. This means that the outer ring of the bearing 30 is clamped by both the retaining cover 10 and the cover 20, preventing axial movement of the outer ring. Furthermore, the bearing 30 is embedded in the accommodating cavity 11, preventing radial movement of the bearing 30 relative to the retaining structure. Thus, the retaining cover 10 and the cover 20 work together to ensure the precise positioning of the bearing 30.

[0049] Third, when the motor shaft 40 passes through the limiting structure and is fixed to the inner ring of the bearing 30, based on the second point mentioned above, the relative position between the motor shaft 40 and the limiting structure is also kept stable, and no relative slippage will occur in the axial direction, and no shaking will occur in the radial direction.

[0050] Based on the above three points, it can be seen that when the first magnet 50 is fixed to the motor shaft 40, the first magnet 50 and the second magnet 64 do not change position in the axial direction of the motor shaft 40. Furthermore, there is no relative movement between the first magnet 50 and the second magnet 64 in the radial direction of the motor shaft 40. This ensures that the relative position of the magnet on the motor shaft 40 and the magnet on the circuit board 60 remains stable, thus preventing inaccurate position detection results.

[0051] Please refer to Figures 5, 7 and 8 again. In some embodiments, a plurality of limiting protrusions 14 are provided on the side of the limiting cover 10 facing the cover body 20. The plurality of limiting protrusions 14 are spaced apart around the opening 12. The cover body 20 is provided with a plurality of limiting holes 23. The plurality of limiting holes 23 are plugged into the plurality of limiting protrusions 14 in a one-to-one correspondence. Therefore, the limiting protrusions 14 can pre-position and install the cover body 20.

[0052] In one embodiment, the position-limiting cover 10 includes a cover body 16 and a mounting flange 17. The cover body 16 forms a receiving cavity 11. The mounting flange 17 is disposed around the opening 12 and is bent outward relative to the cover body 16. The position-limiting protrusion 14 is disposed on the mounting flange 17. The cover body 20 is plate-shaped and is positioned to fit snugly with the mounting flange 17. The position-limiting hole 23 is a notch provided on the edge of the cover body 20.

[0053] Furthermore, the limiting protrusion 14 is provided with a first mounting hole 15, and the mounting base 70 is provided with a second mounting hole 79. Fasteners 78b are inserted through the first and second mounting holes 15, 79 to secure the limiting cover 10 to the mounting base 70. Therefore, the provision of the limiting protrusion 14 not only enables pre-positioning and installation of the cover 20, but also strengthens the limiting cover 10 after the first mounting hole 15 is formed in the limiting cover 10. It also extends the axial length of the first mounting hole 15, increases the connection area between the hole wall of the first mounting hole 15 and the fastener 78b, and improves the stability of the connection. Optionally, the fastener 78b may be a screw, rivet, latch, or the like.

[0054] Referring to FIG. 7 , in some embodiments, the cover 20 and the limiting cover 10 are spot welded. Specifically, the cover 20 is provided with a plurality of welding protrusions 22 spaced apart around the opening 12 and welded to the limiting cover 10. The provision of the welding protrusions 22 creates a gap between the cover 20 and the limiting cover 10, which facilitates the spot welding equipment to operate on the welding protrusions 22. Optionally, the welding protrusions 22 are formed by integrally recessing the cover 20, thereby forming a recess on the side of the cover 20 facing away from the limiting cover 10.

[0055] Referring to Figures 7 and 8 , in some embodiments, the inner wall of the mounting base 70 is formed with a first stepped surface 72, and the mounting flange 17 is overlapped and secured to the first stepped surface 72. In this embodiment, the first stepped surface 72 serves to pre-position the mounting flange 17 axially with respect to the motor shaft 40, preventing the retaining cover 10 from moving toward the mounting flange 17. After axial pre-positioning, the mounting flange 17 is then secured to the first stepped surface 72, completely preventing relative movement between the two.

[0056] In a specific embodiment, the inner wall of the mounting seat 70 is provided with a circle of ribs 73 , and one surface of the ribs 73 forms a first step surface 72 .

[0057] Furthermore, an annular groove 18 is provided at the connection between the cover body 16 and the mounting flange 17 . The annular groove 18 surrounds the opening 12 and is located on a side away from the opening 12 .

[0058] Furthermore, the inner wall of the mounting base 70 is also formed with a second step surface 74, and the circuit board 60 is overlapped and fixed to the second step surface 74. Optionally, the inner wall surface of the mounting base 70 is arranged in a stepped shape to form the second step surface 74. Of course, the inner wall of the mounting base 70 can also be provided with a protrusion to form the second step surface 74. Similarly, the second step surface 74 can also pre-position the circuit board 60 in the axial direction of the motor shaft 40. In this way, the relative positions of the limiting structure and the circuit board 60 in the axial direction are fixed, which is equivalent to ensuring the relative positions of the first magnet 50 and the second magnet 64 in the axial direction.

[0059] The mounting seat 70 may be generally cylindrical with both ends through, and the first step surface 72 and the second step surface 74 are spaced apart along the axial direction of the mounting seat 70 , and the first step surface 72 and the second step surface 74 are disposed opposite to each other.

[0060] Furthermore, the inner wall of the mounting base 70 is provided with a positioning boss 75, one surface of which constitutes at least a portion of the second stepped surface 74. The positioning boss 75 is provided with a positioning post 76 and a fixing hole 77. The circuit board 60 is provided with a positioning hole 61 and a connecting hole 62. The positioning post 76 is plugged into the positioning hole 61. Fasteners 78a are inserted into the fixing hole 77 and the connecting hole 62 to secure the circuit board 60 to the positioning boss 75. In this embodiment, except for the positioning boss 75, the width of the second stepped surface 74 in other locations is relatively narrow, primarily serving to support the circuit board 60. The second stepped surface 74 formed by the positioning boss 75 is relatively wide, not only providing support but also providing sufficient area and strength for the positioning post 76 and the fixing hole 77. The positioning post 76 and the positioning hole 61 cooperate to achieve pre-positioning, which can then be locked using the fastener 78a.

[0061] Furthermore, the motor rotor position angle detection assembly further includes a tray 80. The tray 80 is provided with an escape hole 81 through which the motor shaft 40 passes. The tray 80 is welded to the motor shaft 40 and formed with a mounting groove 82. The first magnet 50 is embedded in and fixed to the mounting groove 82. Optionally, the first magnet 50 and the tray 80 are bonded together with glue, so that the mounting groove 82 can accommodate the glue and the contact area between the first magnet 50 and the mounting groove 82 is relatively large.

[0062] In some embodiments, the tray 80 is positioned between the circuit board 60 and the limiting cover 10. One end of the tray 80 is provided with an abutting protrusion, which extends from the clearance hole 13 on the limiting cover 10 into the limiting cover 10 and contacts the inner race of the bearing 30. By virtue of the contact between the two, the relative position of the first magnet 50 on the tray 80 and the bearing 30 in the axial direction of the motor shaft 40 can be ensured. The position of the bearing 30 on the motor shaft 40 is determined by the limiting cover 10, which is in turn fixed to the mounting base 70. The circuit board 60 is also fixed to the mounting base 70. Therefore, it can be seen that by virtue of the contact between the tray 80 and the bearing 30, the axial distance between the first magnet 50 and the second magnet 64 can be ensured.

[0063] Referring again to Figure 4 , the motor rotor position angle detection assembly further includes a retaining ring 90, which is sleeved and welded to the motor shaft 40. Retaining ring 90 is located on the side of the cover 20, with one end of retaining ring 90 extending into the clearance hole 21 in the cover 20 and contacting the inner ring of the bearing 30. The arrangement of the tray 80 and retaining ring 90 also effectively resists axial impact and pullout forces, significantly enhancing reliability.

[0064] Referring again to Figures 4 and 8 , in some embodiments, the circuit board 60 is located at one end of the motor shaft 40 and has a first surface 63 facing the first magnet 50. The second magnet 64 is fixed to the first surface 63. The vertical distance C between the first surface 63 and the first magnet 50 is greater than or equal to 0.1 mm and less than or equal to 0.4 mm. Optionally, the vertical distance C between the first surface 63 and the first magnet 50 is 0.2 mm. In this embodiment, the vertical distance C refers to the distance parallel to the axial direction of the motor shaft 40. If the vertical distance between the first surface 63 and the first magnet 50 is too small, the end of the motor shaft 40 is easily scratched by the second magnet 64. If the vertical distance between the first surface 63 and the first magnet 50 is too large, the sensing distance between the first magnet 50 and the second magnet 64 is too large, resulting in insensitive sensing. Therefore, limiting the vertical distance between the first surface 63 and the first magnet 50 to between 0.1 mm and 0.4 mm can avoid the above problems.

[0065] An embodiment of the present application also provides an electric toothbrush, which includes a handle and a brush head (not shown in the figure). The handle includes a handle shell (not shown in the figure) and a motor rotor position angle detection component. The motor rotor position angle detection component is installed in the handle shell, and the brush head is located outside the handle shell and is fixed to the motor shaft 40 of the motor rotor position angle detection component. The specific structure of the motor rotor position angle detection component can be found in the above embodiment and will not be repeated here.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present application.

Claims

1. A position angle detection component for a motor rotor, characterized in that Comprising: A limit cover having an accommodating cavity arranged in an open manner; A cover body for covering the opening; A bearing embedded in the accommodating cavity, with both ends of the outer ring of the bearing abutted against the limit cover and the cover body correspondingly, and a relief hole is arranged in the limit cover and / or the cover body corresponding to the inner ring of the bearing; A motor shaft extending into the accommodating cavity through the relief hole and fixed to the inner ring of the bearing; A first magnet fixed relative to the motor shaft and capable of rotating with the motor shaft; and A circuit board provided with a second magnet, and the second magnet is arranged facing the first magnet.

2. The position angle detection assembly of the motor rotor according to claim 1, wherein A plurality of limit protrusions are arranged on the side of the limit cover facing the cover body, and the plurality of limit protrusions are distributed at intervals around the opening; The cover body is provided with a plurality of limit holes, and the plurality of limit holes are inserted into the plurality of limit protrusions in one-to-one correspondence.

3. The position angle detection component of the motor rotor according to claim 1, wherein The cover body is provided with a plurality of welding protrusions, and the plurality of welding protrusions are distributed at intervals around the opening, and the welding protrusions are welded to the limit cover.

4. The position angle detection component of the motor rotor according to claim 1, characterized in that, The position angle detection assembly of the motor rotor further includes a mounting seat, the mounting seat forms a storage space, the limit cover and the cover body are located in the storage space, and one of the limit cover and the cover body is fixed to the mounting seat; the circuit board is fixed to the mounting seat.

5. The position angle detection assembly of the motor rotor according to claim 4, characterized in that The limit cover includes a cover body and a mounting flange, the cover body forms the accommodating cavity, the mounting flange is arranged around the opening and bent outward relative to the cover body, and the cover body is attached to the mounting flange; A first step surface is formed on the inner wall of the mounting seat, and the mounting flange is lapped on the first step surface and fixed.

6. The position angle detection component of the motor rotor according to claim 4, characterized in that, A second step surface is further formed on the inner wall of the mounting seat, and the circuit board is lapped and fixed to the second step surface.

7. The position angle detection component of the motor rotor according to claim 6, characterized in that, A positioning boss is arranged on the inner wall of the mounting seat, one surface of the positioning boss constitutes at least a part of the second step surface, the positioning boss is provided with a positioning post and a fixing hole, the circuit board is provided with a positioning hole and a connection hole, the positioning post is inserted into the positioning hole, and a fastener passes through the fixing hole and the connection hole to fix the circuit board and the positioning boss.

8. The position angle detection component of the motor rotor according to any one of claims 1 to 7, characterized in that, The circuit board is located at one end of the motor shaft and has a first surface facing the first magnet, the second magnet is fixed to the first surface, and the vertical distance between the first surface and the first magnet is greater than or equal to 0.1 mm and less than or equal to 0.4 mm.

9. The position angle detection assembly of the motor rotor according to claim 1, characterized in that, The circuit board is provided with two second magnets, the two second magnets are distributed on the same basic circle, and the central angle of the two second magnets is 90°, and the basic circle is coaxial with the motor shaft; The first magnet is annular and arranged around the motor shaft, the first magnet includes a first semi-circle and a second semi-circle distributed in half, and the magnetic pole directions of the first semi-circle and the second semi-circle are opposite.

10. The position angle detection component of the motor rotor according to claim 1, characterized in that, The position angle detection assembly of the motor rotor further includes a tray, the tray is provided with an avoidance hole for the motor shaft to pass through, the tray is welded and fixed to the motor shaft, the tray forms a mounting groove, and the first magnet is embedded in the mounting groove and fixed thereto.

11. An electric toothbrush, characterized in that, Comprising: A handle housing, a brush head, and a position angle detection component for the motor rotor as described in any one of claims 1 to 10; the detection component is installed inside the handle housing, and the brush head is located outside the handle housing and fixed to the motor shaft of the position angle detection component of the motor rotor.

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