Composite vibration motor for electric toothbrush

Abstract

The utility model belongs to the technical field of electric toothbrushes, and relates to a composite vibration motor for an electric toothbrush, which comprises a first driving part (1) and a second driving part (2), the front end of a first driving shaft (11) of the first driving part (1) is connected with a brush head, and the rear end of the first driving shaft (11) is connected with the front end of the second driving part (2) through a connecting bearing (3). And the rotation of the first driving part (1) does not drive the second driving part (2) to rotate. The first driving part and the second driving part are spliced through the bearing, it is guaranteed that rotation of the first driving part does not drive the second driving part to rotate, and therefore a better effect is achieved.

Description

Technical Field

[0001] The utility model belongs to the technical field of electric toothbrushes and relates to a motor for an electric toothbrush, in particular to a composite vibration motor for an electric toothbrush. Background Art

[0002] The vibration of an electric toothbrush is generated by the built-in motor and transmitted to the brush head to drive the bristles to vibrate. The movement trajectory of the bristles is related to the driving trajectory of the motor. Common built-in motors for electric toothbrushes can be divided into three categories: eccentric motors, sonic motors, and linear motors.

[0003] An eccentric motor is a combination of an eccentric wheel fixed on a rotating motor shaft. When working, the center of gravity of the eccentric wheel is not at the axis center, and acceleration will be generated in all directions during high-speed rotation. This vibration causes the bristles to swing irregularly in any direction. An ultrasonic motor is an oscillating reciprocating motor. When working, the motor rotates back and forth clockwise and counterclockwise at a small angle with its own output shaft as the rotation axis. This motor drives the bristles to swing slightly left and right around the motor shaft. A linear motor is a linear reciprocating motor. When working, the motor shaft reciprocates in a straight line along its own axis. This motor drives the bristles to swing slightly back and forth along the motor shaft.

[0004] It can be seen that the bristles of conventional electric toothbrushes swing in a single direction or irregularly, which is difficult to meet the needs. To this end, Chinese utility model patent 201921699910.8 invented a dual-magnetic circuit electric toothbrush, which realizes two vibration forms of the brush head and achieves the technical effect of enriching the cleaning function of the toothbrush.

[0005] However, when the two degrees of freedom of the dual-freedom motor used in this dual-magnetic circuit electric toothbrush move simultaneously, they will affect each other's magnetic circuits. Specifically, when the sonic rotor rotates, it will drive the linear mover to rotate. At this time, the center of the linear mover's magnetic steel cannot be directly aligned with the stator teeth when viewed from the radial planed surface, resulting in the rotor's driving efficiency not being optimal during linear motion, and the linear magnetic circuit efficiency is reduced; and when the linear mover is driven linearly, it will drive the sonic rotor to axially displace. At this time, when viewed from the axial planed surface, the sonic rotor's magnetic steel and the stator teeth are misaligned, resulting in a reduction in the sonic magnetic circuit efficiency.

[0006] In addition, the efficiency of the sonic magnetic circuit and the linear magnetic circuit under mutual influence will change linearly, and the corresponding current curve in the winding will have more pulsation changes. The smoother the motor current curve, the higher the efficiency. The more chaotic the motor current curve that affects each other, the greater the current fluctuation and the more serious the heating problem. Moreover, the pulsation of the current when the motor is driven will generate more electromagnetic noise.

[0007] Therefore, in view of the defects existing in the above-mentioned prior art, it is necessary to develop a new type of composite vibration motor for electric toothbrush. Utility Model Content

[0008] In order to overcome the defects of the prior art, the utility model proposes a composite vibration motor for an electric toothbrush, wherein the first driving part and the second driving part are connected by a bearing to ensure that the rotation of the first driving part will not cause the second driving part to rotate, thereby achieving better effect.

[0009] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0010] A composite vibration motor for an electric toothbrush comprises a first drive unit and a second drive unit, wherein the front end of a first drive shaft of the first drive unit is connected to a brush head, and wherein the rear end of the first drive shaft is connected to the front end of the second drive unit via a connecting bearing, so that the rotation of the first drive unit will not drive the second drive unit to rotate.

[0011] Preferably, the length L of the rotor and the first magnetic steel of the first driving unit meets the following conditions:

[0012] L=(s+g)*a+d,

[0013] In the formula, s is the single-sided stroke of the mover of the second driving unit, g is the rotor air gap of the first driving unit, a is a coefficient and its value range is between 1-2, and d is the length of the first stator of the first driving unit.

[0014] Preferably, the first driving part is an acoustic wave magnetic circuit driving part, and the second driving part is a linear magnetic circuit driving part.

[0015] Preferably, the first driving part also includes a first casing, a first stator, a first winding bracket, a first winding, a first magnet, a rotor, a first bearing and a first end cover, the rotor is sleeved on the first driving shaft, one side of the first magnet is fixed on the surface of the rotor, and the other side is parallel to the surface of the first stator and separated by a rotor air gap, the first winding is wound on the stator teeth of the first stator through the first winding bracket, the first stator is interference fit with the first casing and the first casing is tight fit with the first end cover, the first end cover is interference fit with the first bearing, and the first bearing enables the first driving shaft to maintain axial movement and rotational freedom.

[0016] Preferably, the rotor air gap is greater than 0 and less than 0.8 mm.

[0017] Preferably, the first end cover is an end cover with a spring sheet and the first bearing is a rolling bearing, the spring sheet of the end cover with a spring sheet and the rolling bearing are in a locking connection, and the rolling bearing and the first drive shaft are in an interference fit.

[0018] Preferably, the second driving portion comprises a second driving shaft, and a front end of the second driving shaft is connected to a rear end of the first driving shaft via the connecting bearing.

[0019] Preferably, the second driving part also includes a second housing, a second stator, a second winding, a second winding bracket, a second magnet, a mover, a second bearing and a second end cover, the mover is interference fit with the first driving shaft, one side of the second magnet is fixed on the surface of the mover, and the other side is parallel to the surface of the second stator and separated by a mover air gap, the second winding is wound on the stator teeth of the second stator through the second winding bracket, the second stator is interference fit with the second housing, the second housing is tightly fit with the second end cover, the second end cover is interference fit with the second bearing, and the second bearing enables the second driving shaft to maintain axial freedom.

[0020] Preferably, the second driving part comprises a mover bracket, and the front end of the mover bracket is connected to the rear end of the first driving shaft through the connecting bearing.

[0021] Preferably, the second driving part further includes an elastic frame, a mover magnetic steel, a third stator, a third winding and a counterweight.

[0022] Compared with the prior art, the composite vibration motor for an electric toothbrush of the utility model has one or more of the following beneficial technical effects:

[0023] 1. The utility model can generate single or multiple degrees of freedom of movement according to the needs of users, and can make the bristles swing in different ways according to the needs of users, so as to achieve more reasonable cleaning of teeth.

[0024] 2. The first driving part and the second driving part of the utility model are connected by bearings, which ensures that the rotation of the first driving part will not cause the second driving part to rotate, thereby not affecting the efficiency of the first driving part and the second driving part.

[0025] 3. The first driving part and the second driving part of the utility model are spliced ​​by bearings, so that the efficiency of the first driving part and the second driving part will not show linear fluctuation changes, thereby reducing heating problems and electromagnetic noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of a composite vibration motor for an electric toothbrush according to the first embodiment of the utility model;

[0027] Figure 2 is a cross-sectional view of a composite vibration motor for an electric toothbrush according to the first embodiment of the utility model;

[0028] Figure 3It is a structural schematic diagram of a composite vibration motor for an electric toothbrush according to a second embodiment of the utility model;

[0029] Figure 4 It is a cross-sectional view of a composite vibration motor for an electric toothbrush according to a second embodiment of the present utility model. DETAILED DESCRIPTION

[0030] Before describing in detail any embodiment of the utility model, it should be understood that the utility model is not limited in its application to the construction and arrangement details of the components described below or illustrated in the following figures. The utility model can have other embodiments and can be practiced or carried out in various ways. In addition, it should be understood that the words and terms used here are for descriptive purposes and should not be considered restrictive. The use of "including" or "having" and its variations herein is intended to cover the items and their equivalents and additional items displayed below. Unless otherwise specified or limited, the terms "install", "connect", "support" and "couple" and their variations are widely used and cover direct installation and indirect installation, connection, support and connection. In addition, "connect" and "couple" are not limited to physical or mechanical connections or connections.

[0031] Furthermore, on the first aspect, in the disclosure of the present invention, the terms "longitudinal", "transverse", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicating the orientation or position relationship are based on the orientation or position relationship shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore the above terms cannot be understood as limitations on the present invention; on the second aspect, the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "one" cannot be understood as a limitation on the quantity.

[0032] [Example 1]

[0033] like Figure 1 As shown, the composite vibration motor for an electric toothbrush according to the first embodiment comprises a first driving part 1 and a second driving part 2. The front end of the first driving shaft 11 of the first driving part 1 is connected to the brush head.

[0034] The first driving unit 1 is an acoustic magnetic circuit driving unit. Figure 2 As shown, the first driving unit 1 further includes a first housing 12 , a first stator 13 , a first winding support 14 , a first winding 15 , a first magnetic steel 16 , a rotor 17 , a first bearing 18 and a first end cover 19 .

[0035] One side of the first magnetic steel 16 is fixed on the surface of the rotor 17, and the other side is parallel to the surface of the first stator 13 and separated by a rotor air gap. Preferably, the rotor air gap is a gap greater than 0 and less than 0.8 mm.

[0036] The first winding 15 is wound on the stator teeth of the first stator 13 through the first winding support 14. The first winding 15 is a coil group formed by winding a wire clockwise or counterclockwise on the stator teeth of the first stator 13, and the coil groups on the symmetrical stator teeth have opposite directions and the same polarity as the corresponding first magnetic steel 16.

[0037] The rotor 17 is interference-fitted with the first drive shaft 11. The first stator 13 is interference-fitted with the first housing 12, and the first housing 12 is tightly fitted with the first end cover 19. The first end cover 19 is interference-fitted with the first bearing 18. The first bearing 18 allows the first drive shaft 11 to maintain axial movement and rotational freedom. In addition, the symmetry centers of the first stator 13 and the rotor 17 coincide.

[0038] During operation, alternating current flows through the first winding 15 to generate a changing electromagnetic field, and the first magnetic steel 16 generates a permanent magnetic field. The two magnetic fields interact with each other to generate an axial force torque to drive the first drive shaft 11 to reciprocate.

[0039] The first end cover 19 may be an end cover with a spring sheet and the first bearing 18 may be a rolling bearing. The spring sheet of the end cover with a spring sheet is locked with the rolling bearing and the rolling bearing is interference fit with the first drive shaft 11. After assembly in this manner, the first drive shaft 11 can maintain axial movement and rotational freedom, while limiting freedom in other directions.

[0040] The second driving unit 2 includes a second driving shaft 21 , a second housing 22 , a second stator 23 , a second winding 24 , a second winding bracket, a second magnetic steel 25 , a mover 26 , a second bearing 27 and a second end cover 28 .

[0041] One side of the second magnetic steel 25 is fixed on the surface of the mover 26, and the other side is parallel to the surface of the second stator 23 and separated by a mover air gap. Preferably, the mover air gap is a gap greater than 0 and less than 0.8 mm. The second winding 24 is wound on the stator teeth of the second stator 23 through the second winding bracket.

[0042] The second magnetic steel 25 is divided into two pieces of magnetic poles with opposite polarities and symmetrically distributed. The second winding 24 is a coil group formed by winding the wire clockwise or counterclockwise on the stator teeth of the second stator 23. The coil groups on the symmetrical stator teeth have opposite directions and the same polarity as the corresponding second magnetic steel 25.

[0043] The second stator 23 is interference-fitted with the second housing 22. The second housing 22 is tightly-fitted with the second end cover 28. The second end cover 28 is interference-fitted with the second bearing 27. The second bearing 27 enables the second drive shaft 21 to maintain axial freedom. The mover 26 is interference-fitted with the second drive shaft 21. Moreover, the symmetry centers of the second stator 23 and the mover 26 coincide.

[0044] During operation, the second winding 24 passes alternating current to generate a changing electromagnetic field. The second magnetic steel 25 generates a permanent magnetic field. The two magnetic fields interact with each other to generate an axial force to drive the second drive shaft 21 to perform reciprocating linear motion.

[0045] The second bearing 27 on the second end cover 28 can be an oil-containing bearing and a linear bearing. The second end cover 28 can also be an end cover with a spring sheet, and the spring sheet is locked with the second drive shaft 21. After the end cover with the spring sheet is assembled, the second drive shaft 21 can maintain the axial degree of freedom while limiting the degrees of freedom in other directions.

[0046] Different from the prior art in which the first drive unit and the second drive unit adopt a through shaft, in the first embodiment, the first drive unit and the second drive unit adopt a two-section shaft. Specifically, the front end of the second drive shaft 21 is connected to the rear end of the first drive shaft 11 through a connecting bearing 3. Thus, it can be ensured that the rotation of the first drive shaft 11 will not cause the second drive shaft 21 to rotate, thereby not affecting the efficiency of the first drive unit and the second drive unit, and can also reduce heating problems and electromagnetic noise.

[0047] Moreover, after adopting the two-section shaft, in order to prevent the rotor 17 from being affected by axial movement, the utility model lengthens the rotor 17 and the first magnetic steel 16 .

[0048] Specifically, the length L of the rotor 17 and the first magnetic steel 16 meets the following conditions:

[0049] L=(s+g)*a+d,

[0050] In the formula, s is the single-sided stroke of the mover 26 of the second driving part 2, g is the rotor air gap of the first driving part 1, a is a coefficient and its value range is between 1-2, and d is the length of the first stator 13 of the first driving part 1.

[0051] Among them, for the mover 26, its initial position can be regarded as point 0, and it can move forward a certain distance, for example, 1mm, which can be regarded as +1; it can also move backward a certain distance, for example, 1mm, which can be regarded as -1. At this time, its total stroke is 2 and the unilateral stroke is 1.

[0052] In the present utility model, the first drive unit 1 and the second drive unit 2 can be driven independently. The first drive unit 1 generates clockwise and counterclockwise reciprocating rotation with the first drive shaft 11 as the rotation center and outputs power through the first drive shaft 11. When working, the first drive shaft 11 is locked and connected with the brush head to provide power for the brush head. The second drive unit 2 generates linear reciprocating motion along the axial direction and outputs power through the second drive shaft 21. When working, the second drive shaft 21 drives the first drive shaft 11 and the brush head to perform reciprocating linear motion via the connecting bearing 3.

[0053] [Example 2]

[0054] The first driving unit in the second embodiment is the same as the first driving unit in the first embodiment, and the difference mainly lies in the second driving unit. Therefore, for simplicity, only the second driving unit of the second embodiment will be described below.

[0055] like Figure 3-Figure 4 As shown, the second driving part 2 includes a mover bracket 29 , an elastic skeleton 210 , a mover magnetic steel 211 , a third stator 212 , a third winding 213 , a support plate and a counterweight 214 .

[0056] Among them, one side of the mover magnet 211 is fixed in the magnet slot, and the other side is parallel to the surface of the third stator 212 and separated by a gap greater than 0 and less than 0.8 mm, hereinafter referred to as the mover air gap. The mover magnet 211 is divided into two pieces, the left and right pieces, and the surface polarity of the magnet facing the stator tooth surface of the third stator 212 is divided into four sections and the polarity distribution of the two pieces of magnets is opposite. For example, the polarity of one piece of magnet is "N", "S", "N" and "S" from left to right, and the polarity of the other piece of magnet is "S", "N", "S" and "N" from left to right.

[0057] The third winding 213 is a coil group formed by winding a wire clockwise or counterclockwise on the stator teeth of the third stator 212. The fixed surface of the mover bracket 29 is divided into two halves, and the two mover brackets are respectively fixed on one half of the fixed surface. The support sheet is between the upper part and the lower part of the elastic skeleton 210, retaining the freedom of relative movement of the upper part and the lower part in the direction of movement while limiting the freedom in other directions, ensuring the stability of the air gap size during the relative movement of the upper part and the lower part.

[0058] Different from the rigid connection between the first drive shaft 11 and the mover bracket 29 in the prior art, in the second embodiment, the front end of the mover bracket 29 is connected to the rear end of the first drive shaft 11 through the connecting bearing 3. That is, the connecting bearing 3 is fixed on a mover bracket and the central axis direction of the connecting bearing 3 is the direction of movement. In this way, it can be ensured that the rotation of the first drive shaft 11 will not cause the mover bracket 29 to rotate, thereby not affecting the efficiency of the first drive unit and the second drive unit, and can also reduce the heating problem and electromagnetic noise.

[0059] During operation, alternating current is passed through the third winding 213 to generate a changing electromagnetic field, and the two pieces of the mover magnets 211 generate permanent magnetic fields with opposite field strengths. The electromagnetic field interacts with the two pieces of permanent magnetic fields to generate driving forces in opposite directions, driving the two pieces of the mover magnets 211 to drive the mover bracket 29 to perform reciprocating linear motion in opposite directions. When the two pieces of the mover bracket 29 perform reverse reciprocating linear motion, the torsion spring will be twisted. When the torsion spring is twisted to the maximum amplitude state, the torsion spring stores the kinetic energy of the mover magnet 211 and the mover bracket 29 as elastic potential energy. When the torsion spring is from the maximum torsion amplitude to the normal state of the torsion spring, the torsion spring converts the stored elastic potential energy into the kinetic energy of the mover magnet and the mover bracket.

[0060] When the electric toothbrush is working, the composite vibration motor for the electric toothbrush of the utility model drives the second driving part, that is, the linear magnetic circuit, alone to drive the brush head to produce linear motion; drives the first driving part, that is, the sonic magnetic circuit, alone to drive the brush head to produce swinging motion; and drives the first driving part and the second driving part at the same time to drive the brush head to produce composite motion.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit the protection scope of the utility model. Those skilled in the art can modify or replace the technical solution of the utility model according to the idea of ​​the utility model without departing from the essence and scope of the technical solution of the utility model.

Claims

1. A composite vibration motor for an electric toothbrush, comprising a first drive unit (1) and a second drive unit (2), wherein the front end of a first drive shaft (11) of the first drive unit (1) is connected to a brush head, characterized in that: The rear end of the first drive shaft (11) is connected to the front end of the second drive part (2) via a connecting bearing (3), so that the rotation of the first drive part (1) will not drive the second drive part (2) to rotate.

2. The composite vibration motor for an electric toothbrush according to claim 1, characterized in that: The length L of the rotor and the first magnetic steel of the first driving part (1) meets the following conditions: L=(s+g)*a+d, In the formula, s is the single-sided stroke of the mover of the second drive unit (2), g is the rotor air gap of the first drive unit (1), a is a coefficient and its value range is between 1 and 2, and d is the length of the first stator of the first drive unit (1).

3. The composite vibration motor for an electric toothbrush according to claim 2, characterized in that: The first driving part (1) is an acoustic wave magnetic circuit driving part, and the second driving part (2) is a linear magnetic circuit driving part.

4. The composite vibration motor for an electric toothbrush according to claim 3, characterized in that: The first driving part (1) further comprises a first housing (12), a first stator (13), a first winding support (14), a first winding (15), a first magnetic steel (16), a rotor (17), a first bearing (18) and a first end cover (19); the rotor (17) is sleeved on the first driving shaft (11); one side of the first magnetic steel (16) is fixed on the surface of the rotor (17), and the other side is kept parallel to the surface of the first stator (13) and separated by a rotor air gap; the first winding (15) is wound on the stator teeth of the first stator (13) through the first winding support (14); the first stator (13) is interference-fitted with the first housing (12) and the first housing (12) is tightly-fitted with the first end cover (19); the first end cover (19) is interference-fitted with the first bearing (18); the first bearing (18) enables the first driving shaft (11) to maintain axial movement and rotational freedom.

5. The composite vibration motor for an electric toothbrush according to claim 4, characterized in that: The rotor air gap is a gap greater than 0 and less than 0.8 mm.

6. The composite vibration motor for an electric toothbrush according to claim 5, characterized in that: The first end cover (19) is an end cover with a spring sheet and the first bearing (18) is a rolling bearing. The spring sheet of the end cover with a spring sheet and the rolling bearing are in a locking connection, and the rolling bearing and the first drive shaft (11) are in an interference fit.

7. The composite vibration motor for an electric toothbrush according to any one of claims 1 to 6, characterized in that: The second driving part (2) comprises a second driving shaft (21), and the front end of the second driving shaft (21) is connected to the rear end of the first driving shaft (11) via the connecting bearing (3).

8. The composite vibration motor for an electric toothbrush according to claim 7, characterized in that: The second driving part (2) further comprises a second housing (22), a second stator (23), a second winding (24), a second winding support, a second magnetic steel (25), a mover (26), a second bearing (27) and a second end cover (28); the mover (26) is interference fit with the first driving shaft (11); one side of the second magnetic steel (25) is fixed on the surface of the mover (26), and the other side is parallel to the surface of the second stator (23) and separated by a mover air gap; the second winding (24) is wound on the stator teeth of the second stator (23) through the second winding support; the second stator (23) is interference fit with the second housing (22); the second housing (22) is tightly fit with the second end cover (28); the second end cover (28) is interference fit with the second bearing (27); the second bearing (27) enables the second driving shaft (21) to maintain axial freedom.

9. The composite vibration motor for an electric toothbrush according to any one of claims 1 to 6, characterized in that: The second driving part (2) comprises a mover bracket (29), and the front end of the mover bracket (29) is connected to the rear end of the first driving shaft (11) via the connecting bearing (3).

10. The composite vibration motor for an electric toothbrush according to claim 9, characterized in that: The second driving part (2) further comprises an elastic frame (210), a mover magnetic steel (211), a third stator (212), a third winding (213) and a counterweight (214).

Images