Toothbrush head for electric toothbrush

Abstract

A toothbrush head (1) for an electric toothbrush, comprising: a stem portion (10), the stem portion (10) having a proximal end and a distal end, and the distal end being configured to be connected to a handle body of the electric toothbrush; a bristle carrier (50), the bristle carrier (50) being rotatably arranged at the proximal end of the stem portion (10); and an oscillating rod (20), the oscillating rod (20) being arranged in the stem portion (10) and oscillates about a rotation axis L1 to drive the bristle carrier (50) to rotate reciprocatingly. The toothbrush head (1) further comprises a brush head permanent magnet (30) and an elastic member (41), wherein the brush head permanent magnet (30) is fixed to the oscillating rod (20); the elastic member (41) is arranged to apply an elastic force between the stem portion (10) and the oscillating rod (20); the brush head permanent magnet (30) comprises a first brush head permanent magnet portion (31) and a second brush head permanent magnet portion (32); the distal ends of the first brush head permanent magnet portion (31) and the second brush head permanent magnet portion (32) facing the stem portion (10) have magnetic pole faces of opposite polarities; the magnetic pole faces provide non-contact magnetic coupling; and the first brush head permanent magnet portion (31) and the second brush head permanent magnet portion (32) are arranged radially offset relative to the rotation axis L1.

Description

Brush head for an electric toothbrush TECHNICAL FIELD

[0001] The present invention relates to the technical field of personal care devices, in particular, the present invention relates to a brush head for an electric toothbrush. BACKGROUND

[0002] In the current market, there are many types of electric toothbrushes, most of which are equipped with a drive device capable of reciprocating motion, which is connected to the cleaning components of the brush head to complete the cleaning action.

[0003] There is an electric toothbrush characterized by a permanent magnet mounted on the drive shaft of the handle. When the brush head is docked with the handle, the permanent magnet is attracted to the moving assembly in the brush head by magnetic force, and with the reciprocating motion of the drive device in the handle, the brush disc of the brush head is driven to reciprocate.

[0004] However, the design of this electric toothbrush has a problem, i.e. there is a direct mechanical connection between the drive shaft of the handle and the moving components of the brush head. At high speed, there may be a small periodic relative motion at the connection, which not only causes energy loss, but also generates high-frequency noise.

[0005] In the face of the increasing demand of consumers for the use experience of electric toothbrushes, there is an urgent need in the market to reduce the high-frequency noise and vibration generated by electric toothbrushes during use, while reducing energy loss. SUMMARY

[0006] To overcome the shortcomings of the prior art, the present invention provides a brush head for an electric toothbrush, the brush head comprising: a shank portion having a proximal end and a distal end, the distal end configured to connect to a handle body of an electric toothbrush; a brush disc rotatably disposed at the proximal end of the shank portion; and a swing lever having a proximal end connected to the brush disc and disposed within the shank portion to swing about a rotational axis L1 to drive the brush disc to reciprocate; wherein the brush head further comprises a brush head permanent magnet fixed to the swing lever and an elastic member arranged to exert an elastic force between the shank portion and the swing lever, the brush head permanent magnet comprising a first brush head permanent magnet portion and a second brush head permanent magnet portion having polar faces of opposite polarity facing the distal end of the shank portion, the polar faces providing a non-contact magnetic force coupling, the first brush head permanent magnet portion and the second brush head permanent magnet portion being disposed radially offset with respect to the rotational axis L1.

[0007] According to an aspect of the present invention, the other magnetic pole faces opposite to the polar faces of the first brush head permanent magnet portion and the second brush head permanent magnet portion are short-circuited by a short-circuiting magnetic conductor, which is held on the swing lever.

[0008] According to another aspect of the present application, the handle portion comprises a housing and a bushing arranged inside a distal end of the housing, the bushing is provided with a pivot portion for pivotally connecting the rocker, the bushing has a hollow portion sized to receive a movable drive shaft permanent magnet arranged on a drive shaft of the handle body, an axis of movement of the drive shaft permanent magnet is parallel to but not coincident with an oscillation axis L1 of the rocker.

[0009] According to another aspect of the present application, a through hole is formed on a proximal end wall of the bushing, the brush head permanent magnet is close to or at least partially inserted into the through hole so that a magnetic pole face of the brush head permanent magnet faces the distal end and is close to the hollow portion of the bushing.

[0010] According to another aspect of the present application, when the drive shaft permanent magnet is received inside the handle portion, the magnetic pole face of the brush head permanent magnet always faces the magnetic pole face of the drive shaft permanent magnet with a gap therebetween.

[0011] According to another aspect of the present application, the elastic member is a coil spring, the coil spring is arranged radially offset with respect to the brush head permanent magnet, a first fixed end of the coil spring is fixed to the rocker, and a second fixed end of the coil spring is fixed to the handle portion. Preferably, the distal end of the rocker is provided with a rocker pivot, and the coil spring is sleeved on the rocker pivot.

[0012] According to another aspect of the present application, the elastic member is a leaf spring, a first fixed end of the leaf spring is fixed to the rocker, and a second fixed end of the leaf spring is fixed to the handle portion through a leaf spring holder, the leaf spring is arranged parallel to or perpendicular to the rocker, and the leaf spring and the brush head permanent magnet are arranged in axial alignment.

[0013] According to another aspect of the present application, the leaf spring holder is further provided, the leaf spring holder is wedge-shaped, an axial cross section of the leaf spring holder tapers from the distal end to the proximal end, an inner surface of the handle portion is provided with a recess matching in shape, and the leaf spring holder is fixed with the handle portion through the shape matching.

[0014] According to another aspect of the present application, the first brush head permanent magnet portion and the second brush head permanent magnet portion are arranged about a rocking midplane of the rocker, and opposite magnetic pole faces of the first brush head permanent magnet portion and the second brush head permanent magnet portion towards the distal end of the handle portion are in the same radial plane and have the same size.

[0015] By using the toothbrush head according to the present application, during movement of the drive shaft permanent magnet inside the handle portion, the drive shaft permanent magnet and the brush head permanent magnet are not in direct contact, and the rocker is pushed to oscillate by using non-contact magnetic force coupling, thus effectively improving noise and vibration of the electric toothbrush and reducing energy loss. BRIEF DESCRIPTION OF DRAWINGS

[0016] For a more complete understanding of the present application, reference is made to the following description taken in conjunction with the accompanying drawings in which:

[0017] Fig. 1 shows a perspective view of the outer profile of a toothbrush head according to a preferred embodiment of the present application.

[0018] Fig. 2 shows a perspective view of a partial cross-section of a toothbrush head according to a first embodiment of the present application.

[0019] Fig. 3 shows a perspective view of a partial cross-section of a toothbrush head according to a first embodiment of the present application.

[0020] Fig. 4 shows a perspective view of a partial cross-section of a swing lever according to a first embodiment of the present application.

[0021] Fig. 5 shows a perspective view of a partial cross-section of a swing lever and a bushing according to a first embodiment of the present application.

[0022] Fig. 6 shows a perspective view of a partial cross-section of a swing lever and a bushing according to a first embodiment of the present application, further including a drive shaft permanent magnet.

[0023] Fig. 7 shows a perspective view of a partial cross-section of a toothbrush head according to a second embodiment of the present application.

[0024] Fig. 8 shows a perspective view of a partial cross-section of a swing lever according to a second embodiment of the present application.

[0025] Fig. 9 shows a perspective view of an assembly of a swing lever and a resilient member according to a second embodiment of the present application.

[0026] Fig. 10 shows a perspective view of an assembly of a swing lever and a resilient member according to a second embodiment of the present application, further including a drive shaft permanent magnet and a brush disc.

[0027] Fig. 11 shows a perspective view of a partial cross-section of a toothbrush head according to a third embodiment of the present application.

[0028] Fig. 12 shows another perspective view of a partial cross-section of a toothbrush according to a third embodiment of the present application.

[0029] List of Reference Numerals 1 toothbrush head 10, 10', 10" handle portion 11 housing 110 positioning shaft 12 bushing 121 pivot hole 122 distal end wall 20, 20', 20" swing lever 21 positioning shaft hole 25 swing lever pivot 30, 30', 30" brush head permanent magnet 31 first brush head permanent magnet 32 second brush head permanent magnet 35, 35', 35" short-circuit flux guide 41 coil spring 42', 42" leaf spring 43', 43" leaf spring holder 50 brush disc 60 drive shaft permanent magnet F magnetic force L1 rotational axis L2 brush disc axis L3 center line of drive shaft permanent magnet DETAILED DESCRIPTION

[0030] The application will be further described below in connection with specific embodiments and drawings, in which more details are set forth in order to provide a thorough understanding of the application. It will be apparent, however, that the application can be practiced in a variety of ways and that the application is not limited to the embodiments described herein which are presented for the purposes of illustration only and should not be construed to limit the scope of the application.

[0031] In the following description, "proximal / near" refers to the side or end of the brush head 1 close to the brush disc 50, while "distal / far" refers to the side or end of the brush head 1 away from the brush disc 50. "Axial / axial direction" refers to the direction along or parallel to the rotation axis L1 of the rocker 20 of the brush head 1, "radial" refers to the radial direction perpendicular to the rotation axis L1 of the rocker 30 of the brush head 1, and "circumferential" refers to the circumferential direction around the rotation axis L1 of the rocker 20.

[0032] Fig. 1 shows a brush head 1 according to the application, which is suitable for use in an electric toothbrush. The brush head 1 is detachably mounted to the handle body of the electric toothbrush. The handle body of the electric toothbrush, which is adapted to the brush head 1, comprises a drive shaft extending from the proximal end of the handle body, the proximal end of the drive shaft being provided with a drive shaft permanent magnet 60, which is generally cylindrical as shown in Fig. 2, the drive shaft bringing the drive shaft permanent magnet into reciprocating linear motion.

[0033] As shown in Fig. 1, the brush head 1 comprises a handle portion 10, the handle portion 10 having a brush disc 50 at its proximal end. The interior of the handle portion 10 is provided with a motion component, the brush disc 50 of the brush head 1 being brought into reciprocating rotary motion about a brush disc axis L2 under the actuation of the motion component. The distal end of the handle portion 10 is provided with a connecting device for connecting the brush head 1 to a matching connecting device on the handle body of the electric toothbrush, for example, the connecting device being in the form of a rotary click device.

[0034] Figs. 2 to 6 show a first embodiment of the brush head 1 according to the application. As shown in Fig. 2, the brush head 1 comprises a rocker 20 located in the handle portion 10. The proximal end of the rocker 20 is connected to the brush disc 50, the two being connected together by a motion coupling structure such as a bevel gear, a cam or the like, so that the reciprocating rotation of the rocker 20 about the rotation axis L1 is transmitted to the brush disc 50, achieving the reciprocating rotary rotation of the brush disc 50 about the brush disc axis L2.

[0035] As shown in Fig. 2, the swing lever 20 is rotatably held in the handle section 10. Preferably, a pivot section is provided at both the proximal end and the distal end of the swing lever 20, which is rotatable relative to the handle section 10, so as to realize the reciprocating rotation of the swing lever 20. In the preferred embodiment, the handle section 10 comprises a housing 11 and a bushing 12 inserted into the housing 11 from the distal end of the housing 11 and fixed thereto. At the proximal end of the swing lever 20, the pivot section is formed by a positioning shaft 110 (see Fig. 12) integrally formed at the proximal end of the housing 11 and a positioning shaft hole 21 formed at the proximal end of the swing lever 20. At the distal end of the swing lever 20, the pivot section is formed by a swing lever pivot 25 at the distal end of the swing lever 20 and a pivot hole 121 or recess formed in the bushing 12. The swing lever pivot 25 can be a metal piece embedded in the distal end of the swing lever 20 by insert molding, or can be integrally formed with the swing lever 20 from the same material. The line connecting the pivot sections at the two ends of the swing lever 20 constitutes the rotation axis L1 of the swing lever 20.

[0036] Fig. 3 shows a sectional view of the swing lever 20 according to the first embodiment of the present application, and Figs. 4 and 5 show the swing lever 20 and the bushing 12 in cooperation. Specifically, the distal end of the swing lever 20 is provided with a brush head permanent magnet 30. As shown in Fig. 5, a through hole is formed in the proximal end wall of the bushing 12 in the handle section 10, and the pole face of the brush head permanent magnet is inserted into the through hole or is close to the through hole, with the pole face exposed to or close to the hollow portion of the bushing 12. Preferably, the pole face of the brush head permanent magnet 30 is flush with the inner surface of the proximal end wall of the bushing 12. In this way, when the brush head is connected to the handle body, the pole face of the brush head permanent magnet 30 will face the pole face of the drive shaft permanent magnet 60 on the drive shaft of the handle body, and during the use of the electric toothbrush, the pole face of the brush head permanent magnet 30 and the pole face of the drive shaft permanent magnet 60 always maintain a gap therebetween, the size of which in the axial direction will change with the axial movement of the drive shaft permanent magnet 60, but the brush head permanent magnet 30 and the drive shaft permanent magnet 60 are always not in contact, in other words, the brush head permanent magnet 30 and the drive shaft permanent magnet 60 constitute a non-contact magnetic force coupling.

[0037] Specifically, the brush head permanent magnet 30 of the present invention includes a first brush head permanent magnet portion (block) 31 and a second brush head permanent magnet portion (block) 32, which are disposed adjacent to each other at the distal end of the swing arm 20, and the magnetic poles of the two near sides are shorted by a shorting conductor 35. Specifically, both the first brush head permanent magnet portion 31 and the second brush head permanent magnet portion 32 have magnetic pole surfaces facing the distal end of the handle portion 10 or facing the drive shaft permanent magnet 60. As shown in FIG6, these two magnetic pole surfaces are configured to have opposite polarities, one being an S pole and the other an N pole, and preferably, the magnetic pole surfaces have the same shape and size. The first and second brush head permanent magnet portions 31 and 32 are preferably symmetrical about the swing midpoint plane. Here, the swing midpoint plane is generally located in the middle position of the swing arm 20 in the swing range of motion and is a plane passing through the axis L1 of the rotation shaft. The magnetic pole portions of the first brush head permanent magnet portion 31 and the second brush head permanent magnet portion 32, which are away from the drive shaft permanent magnet 60, are both connected to the same short-circuit magnetic conductor 35. In this way, the short-circuit magnetic conductor 35 short-circuits the magnetic pole portions near the two brush head permanent magnet portions, guiding the magnetic lines of force of the permanent magnet portions 31 and 32 through it.

[0038] Preferably, both the shorting conductor 35 and the brush head permanent magnet 30 are integrally formed with the swing arm 20 by an embedded molding method. However, the shorting conductor 35 can also be embedded in the swing arm 20, while the brush head permanent magnet 30 is fixed to the shorting conductor 35 with an adhesive.

[0039] As shown in Figure 2, on the one hand, the brush head permanent magnet 30 is radially offset relative to the rotation axis L1 of the swing arm 20; on the other hand, the rotation axis L1 of the swing arm 20 is parallel but not collinear with the center line L3 of the drive shaft permanent magnet 60 inserted into the distal end of the handle portion 10, and there is a radial offset between the rotation axis L1 and the center line L3. Thus, at least when the swing arm 20 is in the swing mid-plane position, the magnetic pole surface of the brush head permanent magnet 30 and the magnetic pole surface of the drive shaft permanent magnet 60 inserted into the handle portion 10 face each other at the radially offset position relative to the rotation axis L1.

[0040] As shown in Figure 6, according to the first embodiment, a helical spring 41, serving as an elastic element, is also provided at the distal end of the rocker arm 20. The helical spring 41 is axially arranged between the rocker arm 20 and the bushing 12, and is also sleeved on the rocker arm pivot 25. The first fixed end of the helical spring 41 is fixedly connected to the rocker arm 20; for example, a socket can be provided at the distal end of the rocker arm, and the first fixed end can be inserted into the socket to achieve a fixed connection. The second fixed end of the helical spring 41 is fixedly connected to the bushing 12.

[0041] To maximize the area of ​​the opposing magnetic pole surfaces of the brush head permanent magnet 30 and the drive shaft permanent magnet 60, preferably, the brush head permanent magnet 30 has an arcuate profile on its outer surface near the handle portion 10 that closely matches or substantially matches the cylindrical arcuate profile of the drive shaft permanent magnet 60. On the other hand, the helical spring 41 and the brush head permanent magnet 30 are arranged radially adjacent to each other, with a certain gap between them to allow relative movement. Preferably, the inner surface of the brush head permanent magnet 30 forms an arcuate shape that matches the cylindrical shape of the outer circumference of the helical spring 41.

[0042] On the other hand, preferably, the radial cross-section of the brush head permanent magnet 30 is adapted to the shape of the through hole formed on the distal end wall 122 of the bushing 12. The shape and size of the through hole should be set to allow the brush head permanent magnet 30 to reciprocate within the through hole as the swing arm 20 swings. For the brush head permanent magnet 30, whose inner and outer surfaces are both arc-shaped, the through hole on the distal end wall 122 of the bushing 12 is arc-shaped, and its circumferential extension covers the entire swing range.

[0043] According to the first embodiment of the present invention, after the toothbrush head 1 is connected to the handle body, the brush plate 50 can rotate and reciprocate as the drive shaft of the handle body moves axially.

[0044] When the drive shaft permanent magnet 60 is driven axially towards the brush head permanent magnet 30 along the drive shaft of the handle body, the magnetic pole surfaces between the drive shaft permanent magnet 60 and the brush head permanent magnet 30 approach each other. The drive shaft permanent magnet 60 causes the magnetic field generated by the two permanent magnet parts 31 and 32 in the brush head permanent magnet 30 to be distorted, thereby generating a magnetic force F (see Figure 6). When the magnetic force F increases to the point that it can overcome the resistance of the helical spring 41, the swing arm 20 is pushed to rotate around the rotation axis L1. When the drive shaft permanent magnet 60 is driven axially away from the brush head permanent magnet 30 along the drive shaft of the handle body, the magnetic force F generated between the opposing magnetic pole surfaces of the drive shaft permanent magnet 60 and the brush head permanent magnet 30 decreases. When the magnetic force F is less than the elastic force of the helical spring 41, the helical spring 41 releases potential energy, pushing the swing arm 30 to rotate around the rotation axis L1. Thus, with the reciprocating motion of the permanent magnet 60 on the drive shaft, the rocker arm 20 achieves reciprocating rotation under the combined action of the changing magnetic force F and the elastic force of the helical spring 41.

[0045] During the movement of the drive shaft permanent magnet 60 inside the handle 10, the drive shaft permanent magnet 60 does not directly contact the brush head permanent magnet 30. Therefore, the noise and vibration of the electric toothbrush are effectively improved, and energy loss is reduced.

[0046] Figures 7 to 10 illustrate the structure of a toothbrush head according to a second embodiment of the present invention. This toothbrush head has a handle portion and a pivot rod 20' pivotally connected inside the handle portion 10'. Unlike the toothbrush head in the first embodiment, the toothbrush head of the second embodiment includes a leaf spring as an elastic member that applies an elastic force to the pivot rod.

[0047] As shown in Figures 8 and 9, in addition to the brush head permanent magnet 30', the shorting conductor 35', and the pivot, the distal end of the lever 20' is also specially provided with a leaf spring 42' and a leaf spring retainer 43' for holding the leaf spring 42'. The extension direction of the leaf spring 42' is substantially parallel to the rotation axis L1 of the lever 20'. The distal end of the leaf spring 42' is fixed to the lever 20', for example, by embedding molding or fastener connection, and the proximal end of the leaf spring 42' is fixed to the handle portion 10' by the leaf spring retainer 43'. In this way, when the lever 20' reciprocates, one end of the leaf spring 42' rotates with the lever 20', while the other end is fixed relative to the handle portion 10'. Thus, the leaf spring 42' deforms approximately around a direction perpendicular to the rotation axis to generate an elastic force.

[0048] Preferably, as shown in Figure 9, the leaf spring retainer 43' and the handle portion 10 are fixed together by a form fit. Preferably, the leaf spring retainer 43' is wedge-shaped, with its axial section tapering from the distal end to the proximal end. The proximal end of the leaf spring 42' is fixed to the proximal end of the leaf spring retainer 43', and the main body of the leaf spring retainer 43' is arranged parallel to the inner surface of the leaf spring 42' near the handle portion 10. A matching mounting recess is formed in the handle portion 10. By inserting the leaf spring 42' along with the rocker arm from the distal end to the proximal end, the leaf spring retainer 43' can be inserted into the mounting recess, thus achieving fixation of the proximal end of the leaf spring 42' relative to the handle portion 10' through a form fit.

[0049] Figures 11 and 12 show a toothbrush head according to a third embodiment of the present invention. The difference from the toothbrush head of the second embodiment is that the leaf spring 42” of the toothbrush head in the third embodiment extends perpendicular to the rotation axis L1. The first end of the leaf spring 42” is fixed to the body of the swing arm 20”, with the fixed position located between the proximal and distal ends of the swing arm 20”, preferably closer to the distal end of the swing arm 20”. The second end of the leaf spring 42” is fixed to the handle portion 10” by a leaf spring retainer 43”, further away from the rotation axis L1 than the first end. A gap is left between the leaf spring 42” and the short-circuited magnet, and the radial length of the leaf spring 42” is greater than its width and thickness. Thus, when the swing arm 20” reciprocates, one end of the leaf spring 42” rotates with the body of the swing arm 20”, while the other end is fixed, thereby deforming the leaf spring 42” about a direction parallel to the rotation axis L1 to generate an elastic force.

[0050] In the third embodiment, the structure of the leaf spring retainer 43” for retaining the leaf spring 42” can be the same as that in the second embodiment. The leaf spring retainer is wedge-shaped, with a cross-section that tapers from the distal end to the proximal end. A matching mounting portion is formed in the shank portion 10”, and the leaf spring retainer 43” is fixed in the shank portion 10” by insertion from the distal end to the proximal end, and then by the proximal end of the bushing inserted into the shank portion 10” abutting against the distal end of the leaf spring retainer.

[0051] In the third embodiment, the leaf spring 42”, leaf spring retainer 43”, rocker arm 20”, shorting magnet 35”, and rocker arm pivot are made into a single integral part by injection molding and are installed as a single component during the installation process.

[0052] The process of realizing the swing of the pendulum in the second and third embodiments is similar to that in the first embodiment, and will not be described again here.

[0053] In the second and third embodiments described above, leaf springs 42' and 42" are both arranged on the opposite side of the short-circuit magnetic conductors 35' and 35" from the axial direction of the brush head permanent magnets 30' and 30"; that is, the brush head permanent magnets 30' and 30" are on the far side of the short-circuit magnetic conductors 35' and 35" while the leaf springs 42' and 42" are arranged on the near side of the short-circuit magnetic conductors 35' and 35"; the brush head permanent magnets 30' and 30" and the leaf springs 42' and 42" are arranged side by side along the axial direction. Compared to helical springs with a radially parallel arrangement, the magnetic pole faces of the brush head permanent magnets 30' and 30" facing the permanent magnet 60 in the second and third embodiments can be set to a larger size.

[0054] In the above embodiments, the elastic element should be appropriately selected so that the resistance it generates in the initial state is less than the magnetic force that can be generated between the relative magnetic pole surfaces when the drive shaft permanent magnet is closest to the brush head permanent magnet, and the elastic force that can be generated when the elastic element deforms is greater than the magnetic force that can be generated between the relative magnetic pole surfaces when the drive shaft permanent magnet is furthest from the brush head permanent magnet.

[0055] While the invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any variations and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the invention, without departing from the scope of the invention, fall within the protection scope defined by the claims of the invention.

Claims

1. A toothbrush head for an electric toothbrush, the toothbrush head comprising: The handle portion has a proximal end and a distal end, the distal end being configured to connect to the handle body of the electric toothbrush; A brush disc, which is rotatably disposed at the proximal end of the handle portion; as well as A swing arm, the proximal end of which is connected to the brush disc, and the swing arm is disposed within the handle portion and swings back and forth around the rotation axis L1 to drive the brush disc to rotate back and forth; Its features are, The toothbrush head also includes a permanent magnet and an elastic element. The permanent magnet is fixed to the lever arm, and the elastic element is arranged between the handle and the lever arm to apply an elastic force. The brush head permanent magnet includes a first brush head permanent magnet portion and a second brush head permanent magnet portion, and the first brush head permanent magnet portion and the second brush head permanent magnet portion have magnetic pole surfaces with opposite polarities at their distal ends facing the handle portion. Furthermore, the first brush head permanent magnet portion and the second brush head permanent magnet portion are radially offset relative to the rotation axis L1.

2. The toothbrush head as described in claim 1, characterized in that, The magnetic pole surfaces of the first and second brush head permanent magnet parts provide non-contact magnetic coupling, and the other magnetic pole surface opposite to the magnetic pole surface is shorted by a shorting conductor, which is fixed to the swing arm.

3. The toothbrush head as described in claim 1, characterized in that, The handle portion includes a housing and a bushing disposed inside the distal end of the housing, the bushing having a pivot portion pivotally connected to the lever. The bushing has a hollow portion, the size of which is set to receive a movable drive shaft permanent magnet disposed on the drive shaft of the handle body. The central axis of the drive shaft permanent magnet located in the hollow portion is parallel to but does not coincide with the swing axis L1 of the swing arm.

4. The toothbrush head as described in claim 3, characterized in that, A through hole is formed on the proximal end wall of the bushing, and the brush head permanent magnet is inserted into the through hole near or at least partially, so that the magnetic pole face of the brush head permanent magnet is exposed or close to the hollow part of the bushing.

5. The toothbrush head as described in claim 1, characterized in that, When the permanent magnet of the drive shaft, which is mounted on the drive shaft of the handle body, is received inside the handle, the magnetic pole face of the permanent magnet of the brush head is always separated from the magnetic pole face of the permanent magnet of the drive shaft by a gap.

6. The toothbrush head as described in claim 1, characterized in that, The elastic element is a helical spring, which is arranged radially adjacent to the permanent magnet of the brush head. The first fixed end of the helical spring is fixed to the swing arm, and the second fixed end of the helical spring is fixed to the handle.

7. The toothbrush head as described in claim 6, characterized in that, The far end of the swing arm is provided with a swing arm pivot, and the helical spring is sleeved on the swing arm pivot.

8. The toothbrush head as described in claim 1, characterized in that, The elastic element is a leaf spring, with its first fixed end fixed to the rocker arm and its second fixed end fixed to the handle via a leaf spring retainer. The leaf spring is arranged parallel to or perpendicular to the swing arm, and the leaf spring and the brush head permanent magnet are arranged axially.

9. The toothbrush head as described in claim 8, characterized in that, It also includes a leaf spring cage, which is wedge-shaped and has an axial section that tapers from the distal end to the proximal end. A matching recess is formed in the inner wall of the handle portion, and the leaf spring retainer is fixed to the handle portion by a shape fit.

10. The toothbrush head as described in claim 1, characterized in that, The first and second permanent magnet parts of the brush head are arranged opposite each other with respect to the swing center plane of the swing arm. The magnetic pole surfaces of the first and second permanent magnet parts with opposite polarities facing the far end of the handle are on the same radial plane and have substantially the same size.

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