Double-degree-of-freedom motor for electric toothbrush

Abstract

The utility model belongs to the technical field of oral care, and particularly relates to a two-degree-of-freedom motor for an electric toothbrush, which comprises an axial driving part and a steering driving part which are both connected with a motor shaft and respectively drive the motor shaft to do axial linear reciprocating motion and circumferential rotary reciprocating motion; the elastic sheet comprises a first fixed end, a second fixed end and an elastic connecting part for connecting the first fixed end and the second fixed end; the position of the first fixed end is fixed and does not change along with the movement of the motor shaft; the second fixed end is fixedly connected with the motor shaft; when the motor shaft has a component of axial linear motion, the second fixed end moves back and forth along with the motor shaft, the elastic connecting part provides the degree of freedom of linear motion, and the distance between the second fixed end and the first fixed end in the axial direction is changed; when the motor shaft has a component of circumferential rotation motion, the second fixed end rotates along with the motor shaft, the elastic connecting part provides the degree of freedom of circumferential rotation, and the second fixed end rotates relative to the first fixed end.

Description

Technical Field

[0001] The utility model belongs to the technical field of oral care, and in particular relates to a double-degree-of-freedom motor for an electric toothbrush. Background Art

[0002] In existing technology, electric toothbrush motors typically only move in one degree of freedom. For example, eccentric motors rotate, brushless vibration motors oscillate within a certain angle, and linear oscillation motors oscillate along a straight line. Different motors are matched to the specific needs of electric toothbrushes, but most electric toothbrushes only vibrate in one degree of freedom.

[0003] To increase the degree of freedom of the electric toothbrush, in addition to the use of superimposed motors, corresponding adjustments are also needed in the structure so that the electric toothbrush can run smoothly in two degrees of freedom without interfering with each other. Utility Model Content

[0004] The present invention is proposed based on the above-mentioned requirements of the prior art. The technical problem to be solved by the present invention is to provide a dual-degree-of-freedom motor for an electric toothbrush to achieve operation in two degrees of freedom without interfering with each other.

[0005] In order to solve the above problems, the technical solutions provided by the present invention include:

[0006] A dual-degree-of-freedom motor for an electric toothbrush is provided, comprising: an axial drive portion connected to the motor shaft, driving the motor shaft to perform axial linear reciprocating motion; a steering drive portion connected to the motor shaft, driving the motor shaft to perform circumferential rotational reciprocating motion; a spring connected to the motor shaft, comprising a first fixed end, a second fixed end, and an elastic connection portion connecting the first fixed end and the second fixed end; the position of the first fixed end is fixed and does not change with the movement of the motor shaft; the second fixed end is fixedly connected to the motor shaft; when the motor shaft has a component of axial linear motion, the second fixed end moves back and forth with the motor shaft, and the elastic connection portion provides the freedom of linear motion, so that the distance between the second fixed end and the first fixed end in the axial direction changes; when the motor shaft has a component of circumferential rotational motion, the second fixed end rotates with the motor shaft, and the elastic connection portion provides the freedom of circumferential rotation, so that the second fixed end rotates at a preset angle relative to the first fixed end.

[0007] By setting the shrapnel, the two driving parts are provided with the required degrees of freedom, so that the motor shaft can perform axial linear motion under the drive of the axial driving part and rotational motion under the drive of the steering driving part. With the support of the shrapnel, the dual-degree-of-freedom motor can operate in a single degree of freedom or in two degrees of freedom, without interfering with each other and being relatively independent, so that the electric toothbrush can operate stably and provide the mode required by the user in a targeted manner.

[0008] Preferably, the dual-degree-of-freedom motor further includes a bearing, the bearing is sleeved on the motor shaft and fixedly connected to the motor shaft, and the second fixed end of the elastic piece is fixedly connected to the bearing.

[0009] Through the above-mentioned arrangement, the motor shaft and the second fixed end of the spring are fixed by the bearing, so that the second fixed end moves relative to the original position following the motor shaft, thereby changing the relative distance between the first fixed end and the second fixed end, and providing deformation through the elastic connection part to allow the output motor shaft to move.

[0010] Preferably, the first fixed end extends in a direction parallel to the axial direction and is fixedly connected to the housing of the motor; the second fixed end extends in a direction perpendicular to the axial direction and is provided with a first opening, the first opening is adapted to the bearing, and the bearing is fixedly arranged in the first opening; at least a partial area of the elastic connection portion extends in a direction perpendicular to the axial direction and is provided with a second opening, the motor shaft passes through the second opening, and there is a gap between the motor shaft and the second opening.

[0011] Preferably, the elastic connection portion includes a first layer and a second layer arranged in parallel, both ends of the first layer and the second layer are connected to the first fixed end and the second fixed end respectively, and the first layer and the second layer are separated by a predetermined distance.

[0012] The above arrangement can provide sufficient supporting force while ensuring a larger stroke, that is, can produce a larger deformation, so that the brush head can produce a larger vibration feeling.

[0013] Preferably, the maximum stress of the spring piece under a stroke of ±1.5 mm is less than 46.9 MPa, and the spring piece can achieve a stroke of 2.5 mm when an axial thrust of 5 N is applied.

[0014] In this way, the axial thrust provided by the axial drive part will be better and the stroke will be larger, the power consumption will be lower, the heat generation will be less, the volume can be made smaller, the maximum stress will be smaller, and the service life of the motor will be significantly improved.

[0015] Preferably, the second fixed end is cylindrical and is arranged around the bearing; the elastic connecting portion includes an arc-shaped area and a radial area connected to the second fixed end, and the radius of the arc-shaped area is greater than the radius of the second fixed end; with the radial area as the head end of the elastic connecting portion, the first fixed end is arranged at the end of the elastic connecting portion.

[0016] Preferably, the motor shaft passes through the axial drive portion and the steering drive portion, and the axial drive portion and the steering drive portion form a drive assembly; two springs are respectively located on both sides of the drive assembly.

[0017] Preferably, the dual-degree-of-freedom motor also includes a ball bearing, which is sleeved on the motor shaft and located in a bearing chamber in an end cover fixedly connected to the motor housing, and moves in the bearing chamber driven by the motor shaft; the ball bearing includes a retainer and balls, and the retainer has a plurality of first spaces for the balls to rotate, and the first spaces are adapted to the balls. The balls are embedded in the first spaces, and their opposite sides are in contact with the inner wall of the bearing chamber and the motor shaft respectively. When the motor shaft moves, the ball bearing generates displacement in the bearing chamber and generates relative motion relative to the motor shaft. The balls will provide the motor shaft with the required degrees of freedom to move driven by the axial drive part and the steering drive part; the motor shaft passes through the axial drive part and the steering drive part, and the axial drive part and the steering drive part form a drive assembly, and the springs and ball bearings are respectively located on both sides of the drive assembly.

[0018] The rolling of the balls provides two driving parts with degrees of freedom. In addition, due to the rolling form, the mechanical damping is small, which can significantly solve the power consumption problem.

[0019] Preferably, the axial drive unit is a linear magnetic circuit motor.

[0020] Preferably, the rotation driving part is an acoustic wave magnetic circuit motor.

[0021] Compared with the prior art, the present invention provides the required degrees of freedom for the vibration of the motor shaft by setting the shrapnel. Since the motor has two degrees of freedom, the position of the first fixed end of the shrapnel is fixed, specifically fixed relative to the outer wall of the electric toothbrush, and the second fixed end is fixed to the motor shaft through a bearing. When the motor shaft vibrates, the second fixed end vibrates accordingly. The first fixed end and the second fixed end are connected by an elastic connection part, so that elastic deformation is provided to provide the position change generated when the motor shaft rotates or moves linearly. The vibrations of the motor shaft under the two driving modes do not interfere with each other and are relatively independent. By setting the elastic connection part in the form of a double-layer thin wall to provide stable support, it is ensured that it has a larger stroke when subjected to external force, that is, a corresponding larger deformation is generated, so that the brush head can generate a larger vibration. In addition, the degree of freedom can also be provided by a ball bearing. The ball takes the form of rolling, so that the mechanical damping is small, which can significantly solve the power consumption problem. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of this specification. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0023] Figure 1 Schematic diagram of the structure of the dual-degree-of-freedom motor in an embodiment of the present utility model;

[0024] Figure 2 This is a schematic structural diagram of a spring in an embodiment of the present utility model;

[0025] Figure 3 This is a schematic structural diagram of another spring in an embodiment of the present utility model;

[0026] Figure 4 This is a structural diagram of another dual-degree-of-freedom motor in an embodiment of the present utility model;

[0027] Figure 5 Schematic diagram of the structure of the bearing chamber in the embodiment of the present utility model;

[0028] Figure 6 This is another structural schematic diagram of yet another dual-degree-of-freedom motor in an embodiment of the present utility model;

[0029] Figure 7 Schematic diagram of another structure of the dual-degree-of-freedom motor in an embodiment of the present utility model.

[0030] Reference numerals:

[0031] 1. Axial drive unit; 2. Steering drive unit; 3. Shrapnel; 4. First fixed end; 5. Second fixed end; 6. Elastic connection unit; 7. Motor shaft; 8. First layer; 9. Second layer; 10. Ball bearing; 11. Bearing chamber; 12. Retainer; 13. Ball; 14. First opening; 15. Second opening; 16. Housing; 17. Arc-shaped area; 18. Radial area; 19. End cover; 20. Bearing. DETAILED DESCRIPTION

[0032] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are 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.

[0033] In the description of the embodiments of the present invention, it should be noted that, unless otherwise expressly specified or limited, the term "connected" should be understood in a broad sense. For example, it can mean a fixed connection, a detachable connection, or an integral connection. It can be a mechanical connection, an electrical connection, a direct connection, or an indirect connection through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present invention can be understood according to the specific circumstances.

[0034] The terms "top," "bottom," "above," "below," and "on" used throughout the description refer to relative positions of components of a device, such as the relative positions of top and bottom substrates within a device. It will be understood that devices are multifunctional regardless of their orientation in space.

[0035] To facilitate understanding of the embodiments of the present application, further explanation will be given below with reference to specific embodiments in conjunction with the accompanying drawings. The embodiments do not constitute a limitation on the embodiments of the present application.

[0036] This embodiment provides a dual-degree-of-freedom motor for an electric toothbrush. Figure 1-Figure 7 shown.

[0037] The dual-degree-of-freedom motor for the electric toothbrush, hereinafter referred to as the dual-degree-of-freedom motor, includes an axial drive unit 1 , a steering drive unit 2 , a spring 3 and a bearing 20 .

[0038] The axial drive unit 1 includes an axial magnetic circuit that can provide an axial driving force to drive the rotor of the axial drive unit 1 to reciprocate axially within a certain stroke.

[0039] Furthermore, the axial drive unit 1 is a linear magnetic circuit motor.

[0040] Since the linear magnetic circuit motor drives the motor shaft 7 to move, which is known to those skilled in the art, and the present invention does not improve the structure, nor does it make any creative content, based on the above reasons, this part of the content will not be described in detail here.

[0041] The axial drive unit 1 is connected to the motor shaft 7 , thereby driving the motor shaft 7 to perform axial linear reciprocating motion.

[0042] The steering drive unit 2 includes a steering magnetic circuit that can provide a force to rotate the rotor of the axial drive unit 1. Specifically, under the action of the steering magnetic circuit, the drive unit rotor can perform high-frequency reciprocating rotation within a certain angle.

[0043] Furthermore, the steering drive unit 2 is an acoustic wave magnetic circuit motor.

[0044] The steering drive unit 2 is connected to the motor shaft 7, thereby driving the motor shaft 7 to perform circumferential rotation and reciprocating motion.

[0045] Shrapnel 3, such as Figure 2 、 Figure 3 and Figure 7 As shown, it includes a first fixed end 4, a second fixed end 5 and an elastic connecting portion 6. The spring can keep the rotor (mover) in the driving part centered so that it can operate normally, otherwise the magnet and stator in the driving part will be attracted together and cannot operate normally.

[0046] It should be noted that the above naming can be considered as a distinction between different positions of the integrated spring piece 3, and does not mean that the spring piece 3 must be a detachable or removable structure. Of course, the detachable or removable form is not excluded.

[0047] The first fixed end 4 is connected to the inner wall of the housing 16 of the motor, that is, the position of the first fixed end 4 is fixed and does not change with the movement of the motor shaft 7 .

[0048] The second fixed end 5 is fixedly connected to the motor shaft 7 , that is, the second fixed end 5 will move along with the movement of the motor shaft 7 .

[0049] Furthermore, the second fixed end 5 is connected to the motor shaft 7 via a bearing 20. Specifically, a bearing 20 is fixedly sleeved on the motor shaft 7, and the bearing 20 is fixedly connected to the second fixed end 5, so that the second fixed end 5 is fixedly connected to the motor shaft 7 for following motion.

[0050] The elastic connecting portion 6 has two ends respectively connected to the first fixed end 4 and the second fixed end 5. When the second fixed end 5 moves with the motor, since the first fixed end 4 is fixed in position, the elastic connecting portion 6 will provide the second fixed end 5 with the required degree of freedom when moving.

[0051] Specifically, when the motor shaft 7 has an axial linear motion component, the second fixed end 5 moves back and forth with the motor shaft 7, and the elastic connection portion 6 provides the freedom of linear motion, so that the distance between the second fixed end 5 and the first fixed end 4 in the axial direction changes. When the motor shaft 7 has a circumferential rotational motion component, the second fixed end 5 rotates with the motor shaft 7, and the elastic connection portion 6 provides the freedom of circumferential rotation, so that the second fixed end 5 rotates at a preset angle relative to the first fixed end 4. The above-mentioned axial linear motion and circumferential rotational motion can be generated separately or simultaneously. The structural setting of the spring 3 can ensure that when the above-mentioned two degrees of freedom are generated separately, they can provide adaptive degrees of freedom; when the above-mentioned two degrees of freedom are generated simultaneously, it can ensure that the movements in the two directions are carried out simultaneously and do not interfere with each other.

[0052] Furthermore, the elastic connecting portion 6 includes a first layer 8 and a second layer 9 arranged in parallel. The two ends of the first layer 8 are connected to the first fixed end 4 and the second fixed end 5 respectively. Similarly, the two ends of the second layer 9 are also connected to the first fixed end 4 and the second fixed end 5 respectively.

[0053] When the electric toothbrush is required to provide greater vibration, the motor shaft 7 needs to have a longer stroke to drive the brush head to generate greater vibration, thereby cleaning the teeth as thoroughly as possible. To achieve a longer stroke, the elastic connecting portion 6 needs to be as thin as possible to reduce the local stress of the material. However, if the elastic connecting portion 6 is too thin, the radial support force of the spring 3 will be weakened. Therefore, the elastic connecting portion 6 is configured as a two-layer thin wall to provide sufficient support, ensuring a longer stroke while providing stable support.

[0054] In a feasible implementation of this embodiment, as Figure 2 and Figure 7As shown, the first fixed end 4 of the spring piece 3 extends in a direction parallel to the axial direction and is fixedly connected to the housing 16 of the motor. The second fixed end 5 extends in a direction perpendicular to the axial direction and is provided with a first opening 14. The first opening 14 is adapted to the bearing 20, and the bearing 20 is fixedly arranged in the first opening 14. At least a portion of the elastic connection portion 6 extends in a direction perpendicular to the axial direction and is provided with a second opening 15. The motor shaft 7 passes through the second opening 15, and there is a gap between the motor shaft 7 and the second opening 15. The portion of the elastic connection portion 6 extending in the direction perpendicular to the axial direction is longer than the length of the second fixed end 5 in the axial direction, thereby preventing the first fixed end 4 and the second fixed end 5 from colliding or being squeezed when the motor shaft 7 moves, thereby providing a higher degree of freedom and facilitating the movement of the motor shaft 7.

[0055] The above-mentioned spring clip 3 can ensure that it is formed within the range of ±1.5mm, the maximum stress of the spring clip 3 is less than 46.9MPa, and the spring clip 3 can achieve a stroke of 2.5mm when an axial thrust of 5N is applied. In this way, the axial thrust provided by the linear magnetic circuit will be better and the stroke will be larger. The power consumption of the linear magnetic circuit will be lower, the motor will generate less heat and the volume can be made smaller. The smaller maximum stress will significantly improve the service life of the motor.

[0056] In another embodiment of this embodiment, Figure 3 As shown, the second fixed end 5 is cylindrical and has a ring cross section. The bearing 20 is adapted to the internal space of the second fixed end 5 so that the bearing 20 can be fixedly arranged in the cylindrical space of the second fixed end 5. The elastic connecting portion 6 includes an arcuate area 17 and a radial area 18. The radial area 18 extends in the radial direction, and its two ends are respectively connected to the second fixed end 5 and the arcuate area 17. The arcuate area 17 includes a first layer 8 and a second layer 9 that are parallel and spaced a preset distance apart so as to ensure a larger stroke while providing stable support. The arcuate area 17 is close to a circular ring but is not closed. It is arranged around the periphery of the second fixed end 5, that is, the radius of the arcuate area 17 is greater than the radius of the second fixed end 5. With the radial area 18 as the head end of the arcuate area 17, the first fixed end 4 is located at the end of the arcuate area 17. The first fixed end 4 is fixedly connected to the housing 16 of the motor.

[0057] The above-mentioned spring piece 3 provides a maximum stress of 2.6 MPa within a travel range of ±1 mm and can withstand a thrust of 0.8 N. Its performance is also far superior to the existing spring piece 3 solution.

[0058] The motor shaft 7 passes through the axial drive part 1 and the steering drive part 2, and the axial drive part 1 and the steering drive part 2 form a drive assembly. Two spring clips 3 are arranged on both sides of the drive assembly, that is, they are arranged on the motor shaft 7 in the order of spring clip 3, steering drive part 2, axial drive part 1 and spring clip 3.

[0059] In addition to the spring piece 3 , the ball bearing 10 can also provide freedom of movement for the motor shaft 7 .

[0060] The ball bearing 10 is arranged based on the following structural environment:

[0061] like Figure 6 and Figure 4 As shown, the end cover 19 of the motor is fixedly connected to the housing 16. The space formed by the end cover 19 has a bearing chamber 11 for placing a bearing 20. The ball bearing 10 is arranged in the bearing chamber 11, and the space occupied by the ball bearing 10 is smaller than the internal space of the bearing chamber 11, so that the ball bearing 10 can move in the limited space of the bearing chamber 11. Specifically, the axial length of the bearing chamber 11 is greater than the axial length of the ball bearing 10, so that the ball bearing 10 can move in the axial direction.

[0062] like Figure 5 As shown, the ball bearing 10 is sleeved on the motor shaft 7. The ball bearing 10 includes a retainer 12 and balls 13. The retainer 12 is cylindrical and has multiple first spaces formed therein. The first spaces are adapted to accommodate the balls 13, so that when the balls 13 are embedded in the first spaces, they can roll within the first spaces. The two sides of the balls 13 are in contact with the inner wall of the bearing chamber 11 and the motor shaft 7, respectively. When the motor shaft 7 moves, the ball bearing 10 moves relative to the bearing chamber 11 while also generating relative motion with respect to the motor shaft 7. Thus, the ball bearing 10 provides the required degrees of freedom for the movement of the motor shaft 7.

[0063] When motor shaft 7 performs linear reciprocating motion in the axial direction, the displacement stroke of ball bearing 10, driven by balls 13, is one-half the stroke of motor shaft 7. When motor shaft 7 performs circumferential rotational motion, the rotation angle of roller bearing 20, driven by balls 13, is one-half the shaft's rotation angle. The degree of freedom provided by ball bearing 10 ensures that the axial motion and circumferential rotational motion of motor shaft 7 do not interfere with each other, allowing both degrees of freedom to operate simultaneously or independently.

[0064] Based on the rolling of the balls 13 , the mechanical damping received by the axial drive unit 1 and the steering drive unit 2 is small when they are driven, which can significantly improve the power consumption problem.

[0065] Two ball bearings 10 are arranged on both sides of the driving assembly, which can also provide the necessary freedom for the movement of the motor shaft 7 in two directions, thereby achieving high cleaning of the teeth.

[0066] In addition, it can also be arranged in the form of a ball bearing 10 and a spring 3 respectively located on both sides of the drive component, which can also achieve the above-mentioned effect, ensuring that the movements of the axial drive part 1 and the steering drive part 2 do not interfere with each other, so that the rotors of the above-mentioned two drive parts can operate independently of each other and do not affect each other when running at the same time.

[0067] The specific implementation methods described above further illustrate the purpose, technical solutions and beneficial effects of this application. It should be understood that the above description is only the specific implementation methods of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application should be included in the scope of protection of this application.

Claims

1. A dual-degree-of-freedom motor for an electric toothbrush, characterized in that: include: The axial drive part is connected to the motor shaft and drives the motor shaft to perform axial linear reciprocating motion; The steering drive unit is connected to the motor shaft and drives the motor shaft to perform circumferential rotation and reciprocating motion; A spring piece connected to the motor shaft, comprising a first fixed end, a second fixed end, and an elastic connecting portion connecting the first fixed end and the second fixed end; The position of the first fixed end is fixed and does not change with the movement of the motor shaft; The second fixed end is fixedly connected to the motor shaft; When the motor shaft has an axial linear motion component, the second fixed end moves forward and backward with the motor shaft, and the elastic connection portion provides freedom of linear movement, so that the distance between the second fixed end and the first fixed end in the axial direction changes; When the motor shaft has a circumferential rotation component, the second fixed end rotates with the motor shaft, and the elastic connection portion provides circumferential rotation freedom, so that the second fixed end rotates at a preset angle relative to the first fixed end.

2. The dual-degree-of-freedom motor for an electric toothbrush according to claim 1, characterized in that: The dual-degree-of-freedom motor further includes a bearing, which is sleeved on the motor shaft and fixedly connected to the motor shaft, and the second fixed end of the elastic piece is fixedly connected to the bearing.

3. The dual-degree-of-freedom motor for an electric toothbrush according to claim 2, characterized in that: The first fixed end extends in a direction parallel to the axial direction and is fixedly connected to the housing of the motor; The second fixed end extends in a direction perpendicular to the axial direction, and is provided with a first opening, the first opening being adapted to fit the bearing, and the bearing being fixedly disposed in the first opening; At least a portion of the elastic connection portion extends in a direction perpendicular to the axial direction, and a second opening is provided thereon. The motor shaft passes through the second opening, and a gap exists between the motor shaft and the second opening.

4. The dual-degree-of-freedom motor for an electric toothbrush according to any one of claims 1 to 3, characterized in that: The elastic connection portion includes a first layer and a second layer arranged in parallel, both ends of the first layer and the second layer are connected to the first fixed end and the second fixed end respectively, and the first layer and the second layer are separated by a predetermined distance.

5. The dual-degree-of-freedom motor for an electric toothbrush according to claim 4, characterized in that: The maximum stress of the spring fragment is less than 46.9MPa under ±1.5mm stroke, and the spring fragment can achieve a stroke of 2.5mm when an axial thrust of 5N is applied.

6. The dual-degree-of-freedom motor for an electric toothbrush according to claim 1, characterized in that: The second fixed end is cylindrical and is arranged around the bearing; The elastic connecting portion includes an arc-shaped area and a radial area connected to the second fixed end, and the radius of the arc-shaped area is greater than the radius of the second fixed end; The radial region is regarded as the head end of the elastic connection portion, and the first fixed end is arranged at the tail end of the elastic connection portion.

7. The dual-degree-of-freedom motor for an electric toothbrush according to claim 1, characterized in that: The motor shaft passes through the axial drive portion and the steering drive portion, and the axial drive portion and the steering drive portion form a drive assembly; The two springs are respectively located on both sides of the driving assembly.

8. The dual-degree-of-freedom motor for an electric toothbrush according to claim 1, characterized in that: The dual-degree-of-freedom motor further includes a ball bearing, which is sleeved on the motor shaft and located in a bearing chamber in an end cover fixedly connected to the motor housing, and moves in the bearing chamber driven by the motor shaft; The ball bearing includes a retainer and balls. The retainer has a plurality of first spaces for the balls to rotate. The first spaces are adapted to the balls. The balls are embedded in the first spaces, with opposite sides of the retainer contacting the inner wall of the bearing chamber and the motor shaft respectively. When the motor shaft moves, the ball bearing is displaced in the bearing chamber and simultaneously moves relative to the motor shaft. The balls provide the motor shaft with the required degrees of freedom to move under the drive of the axial drive unit and the steering drive unit. The motor shaft passes through the axial drive part and the steering drive part, and the axial drive part and the steering drive part form a drive assembly. The elastic sheet and the ball bearing are respectively located on both sides of the drive assembly.

9. The dual-degree-of-freedom motor for an electric toothbrush according to claim 1, characterized in that: The axial driving part is a linear magnetic circuit motor.

10. The dual-degree-of-freedom motor for an electric toothbrush according to claim 1, characterized in that: The steering drive unit is an acoustic wave magnetic circuit motor.

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