Electric toothbrush and its drive motor

Provided are an electric toothbrush and its drive motor, which comprises a U-shaped magnetic yoke, a rotary output component, a second magnetic yoke and four permanent magnets. The two support legs of the U-shaped yoke are respectively wound with coils, enabling the two leg end faces to generate alternating magnetic poles under the control of circuit. The four permanent magnets are centrosymmetrically disposed about a rotatory central line, the first and the fourth magnet are of the same polarity, the second and the third magnet are of the same polarity; the first and the second magnet are of the opposite polarity, disposed corresponding to the first leg; the third and the fourth magnet are of the opposite polarity, disposed corresponding to the second leg. Under the control of circuit, the driving permanent magnets drive the second yoke and the rotary output component to reciprocatively rotate about the rotatory central line.

TECHNICAL FIELD

The present disclosure relates to a motor, in particular a motor that can output a reciprocating rotational motion.

FIELD BACKGROUND

An electric motor is an electromagnetic device that converts electrical energy into mechanical energy based on the law of electromagnetic induction. It is widely used in various fields and is an indispensable prime motor for today's society, providing power source for a large number of electrical appliances or machines.

An electric toothbrush is a kind of motor-powered device. At present, the drive motor of electric toothbrush usually includes a mountain-shaped iron-core magnet yoke (also called E-shaped magnet yoke), permanent magnet (one piece or two pieces), and rotary output component, the permanent magnet drives the rotary output component to reciprocatively rotate under the action of a coil mounted on the mountain-shaped iron-core yoke. However, the magnetic flux of the middle support of the mountain-shaped iron-core yoke is large, the magnetic flux of the two ends of the magnetic yoke is small, and the force of the permanent magnet is small; and the housing and the rotary output component are required not to have magnetic conductive material to affect the magnetic circuit. Such kind of electric toothbrush require sufficient torque transmission, and must be guaranteed with spring resonance.

SUMMARY

The disclosure provides a new type of electric toothbrush and a drive motor thereof.

The drive motor provided includes:

a U-shaped magnetic yoke, the U-shaped magnetic yoke has a first support leg and a second support leg, and the first support leg and the second support leg are respectively wound with coils;

a control circuit, the control circuit is electrically connected to the coils and generates alternating pulses, to generate alternating magnetic poles at the end faces of the two support legs of the U-shaped magnetic yoke;

a rotary output component, the rotary output component can reciprocatively rotate about a rotatory central line;

a second magnetic yoke, the second magnetic yoke is disposed at one end of the rotary output component near the U-shaped magnetic yoke; and

four permanent magnets, the permanent magnets are fixedly mounted on the second yoke; the four permanent magnets are centrosymmetrically disposed about a rotatory central line, they are a first permanent magnet, a second permanent magnet, a third permanent magnet and a fourth permanent magnet; the outer faces of the first permanent magnet and the fourth permanent magnet are of the same polarity, and the outer faces of the second permanent magnet and the third permanent magnet are of the same polarity; the outer faces of the first permanent magnet and the second permanent magnet are of the opposite polarity and are disposed corresponding to the end face of the first support leg; the outer faces of the third permanent magnet and the fourth permanent magnet are of the opposite polarity and are disposed corresponding to the end face of the second support leg; there is air gap between the end face of the permanent magnet and its corresponding support leg, and under the control of the control circuit, the driving permanent magnets drive the second yoke and the rotary output component to reciprocatively rotate about the rotatory central line.

As a further improvement of the drive motor, the rotatory central line of the rotary output component is perpendicular to the end face of support leg of the U-shaped magnetic yoke, and passes through the symmetrical center point of the end faces of the first leg and the second leg.

As a further improvement of the drive motor, the end face of the first leg and the second leg is inclined face with an inclination angle of α, the rotatory central line of the rotary output component is perpendicular to the inclined face.

As a further improvement of the drive motor, the inclination angle α takes a value of 3°≤α≤8°.

As a further improvement of the drive motor, the gap between the first permanent magnet and the second permanent magnet is smaller than the length of the first leg end face in the direction in which the first permanent magnet and the second permanent magnet lie, the gap between the third permanent magnet and the fourth permanent magnet is smaller than the length of the second leg end face in the direction in which the third permanent magnet and the fourth permanent magnet lie.

As a further improvement of the drive motor, the rotary output component comprises a rotating shaft rotatably mounted on a support body; and a resonance component, the resonance component resonates with the rotating shaft during the reciprocal rotation about the rotating shaft, to increase the rotational amplitude and the torque of the rotating shaft.

As a further improvement of the drive motor, the resonance component includes a position limiter that rotates together with the rotating shaft and a resonator with elasticity, and the resonator is disposed on the reciprocal rotation trace of the position limiter, the position limiter causes the resonator to deform when reciprocatively rotating about the rotating shaft.

As a further improvement of the drive motor, the resonance component comprises a position limiter and a resonator with elasticity, the resonator rotates together with the rotating shaft, the position limiter limits the rotation of the resonator, causing the resonator to deform when rotating.

As a further improvement of the drive motor, the rotating shaft comprises a drive shaft and an output shaft, and the drive shaft and the output shaft are fixedly connected by a coupling body.

As a further improvement of the drive motor, an elastic body for absorbing the moment of inertia of the rotating shaft is disposed in the rotating direction of the rotating shaft, and the elastic characteristic of the elastic body is above quadratic curve, and the elastic body is a sphere, an elliptical sphere, a cylinder, an elliptical cylinder, a semi-circular silicone or a rubber.

The electric toothbrush provided by the present application, comprises the drive motor of any of the above and a brush head, and the brush head is mounted on the rotary output component of the drive motor.

The driving motor provided by the present application comprises a U-shaped magnet yoke, a rotary output component, a second magnet yoke and four permanent magnets. The two support legs of the U-shaped magnetic yoke are respectively wound with coils, which enable the end faces of the two legs to generate alternating magnetic poles under the control circuit. The four permanent magnets are centrosymmetrically disposed about a rotatory central line, the outer faces of the first permanent magnet and the fourth permanent magnet are of the same polarity, the outer faces of the second permanent magnet and the third permanent magnet are of the same polarity; and the outer faces of the first permanent magnet and the second permanent magnet are of the opposite polarity and are disposed corresponding to the first leg; the outer faces of the third permanent magnet and the fourth permanent magnet are of the opposite polarity and are disposed corresponding to the second leg. Under the control of control circuit, the driving permanent magnets drive the second yoke and the rotary output component to reciprocatively rotate about the rotatory central line. The design of the U-shaped yoke corresponding to four permanent magnets and the second magnetic yoke is different from the prior art, it's torque is larger than that of the existing motor of the same power, the magnetic flux is large, and the driving power is correspondingly reduced.

DETAILED DESCRIPTION

The first embodiment provides a drive motor that can output a reciprocating rotational motion.

Referring toFIGS. 1 and 2, the drive motor comprises:

a U-shaped magnetic yoke100, the U-shaped magnetic yoke100has a first support leg110and a second support leg120, and the first support leg110and the second support leg120are respectively wound with coils210;

a control circuit220, the control circuit220is electrically connected to the coils210and generates alternating pulses, to generate alternating magnetic poles at the end faces111,121of the two support legs of the U-shaped magnetic yoke100;

a rotary output component500, the rotary output component500can reciprocatively rotate about a rotatory central line C;

a second magnetic yoke300(to distinguish it from the U-shaped yoke100, it is called second yoke), the second magnetic yoke300is disposed at one end of the rotary output component500near the U-shaped magnetic yoke100; and four permanent magnets, the permanent magnets are fixedly mounted on the second yoke300; the four permanent magnets are centrosymmetrically disposed about a rotatory central line C, they are a first permanent magnet410, a second permanent magnet420, a third permanent magnet430and a fourth permanent magnet440; the outer faces of the first permanent magnet410and the fourth permanent magnet440(the outer faces of the fourth permanent magnet440is the end surface of441shown inFIG. 5, and the outer faces of the other permanent magnets are the same as the fourth permanent magnet440, which will not be shown in the figure) are of the same polarity, and the outer faces of the second permanent magnet420and the third permanent magnet430are of the same polarity; the outer faces of the first permanent magnet410and the second permanent magnet420are of the opposite polarity and are disposed corresponding to the end face111of the first support leg110; the outer faces of the third permanent magnet430and the fourth permanent magnet440are of the opposite polarity and are disposed corresponding to the end face121of the second support leg120; there is air gap between the end face of the permanent magnet and its corresponding support leg, and under the control of the control circuit220, the driving permanent magnets410,420,430and440drive the second yoke300and the rotary output component500to reciprocatively rotate about the rotatory central line C.

Referring toFIG. 3, the four permanent magnets410,420,430,440may be arranged in a rectangular shape centrosymmetrically around the rotatory central line C. The horizontal distance between the first permanent magnet410and the fourth permanent magnet440is equal to the horizontal distance between the second permanent magnet420and the third permanent magnet430, and the vertical distance between the first permanent magnet410and the second permanent magnet420is equal to the vertical distance between the fourth permanent magnet440and the third permanent magnet430.

The U-shaped magnetic yoke100, the second magnetic yoke300, the rotary output component500and the permanent magnets are mounted within a housing800, wherein the rotary output component500is rotatably mounted within the housing800. The housing800referred to herein may be a housing dedicated to the motor or a housing of an electric appliance using the motor.

When energized, each leg of the U-shaped yoke100corresponds to two permanent magnets, ensuring that the torque is sufficiently large to realize the entire reciprocating swing process without external force. The design of the U-shaped yoke corresponding to four permanent magnets and the second magnetic yoke is different from the prior art, which makes the torque of the drive motor larger than that of the existing motor of the same power, the magnetic flux is large, and the driving power is correspondingly reduced.

Specifically, referring toFIGS. 1, 2, and 3, it is assumed that the end faces of the first permanent magnet410and the fourth permanent magnet440are N poles, and the end faces of the second permanent magnet420and the third permanent magnet430are S poles. When the coil210is energized, if the end face of the first leg110is N pole and the end face of the second leg120is S pole, the N pole of the first leg110will create a suction force F2 to the S pole of the second permanent magnet420, and a repulsive force F1 to the N pole of the first permanent magnet410. Similarly, the S pole of the second leg120will generate a suction force F4 to the N pole of the fourth permanent magnet440and a repulsive force F3 to the S pole of the third permanent magnet430, thereby rotating the rotary output component500clockwise, as shown inFIG. 3. Then the total torque of the rotary output component is (F1+F2+F3+F4)·force radius, and the force radius is the distance from the magnetic force to the center of rotation.

When the current direction in the coils210changes, if the end face of the first leg110is S pole, and the end face of the second leg120is N pole, the S pole of the first leg110will create a repulsive force to the S pole of the second permanent magnet420, and a suction force to the N pole of the first permanent magnet410. Similarly, the N pole of the second leg120will create a repulsive force to the N pole of the fourth permanent magnet440, and generate a suction force to the S pole of the third permanent magnet430, thereby rotating the rotary output component500counterclockwise, as shown inFIG. 3.

In summary, the coils210are connected to the control circuit220, and the control circuit220generates an alternating pulse with adjustable pulse width, so that the end face of the U-shaped yoke100generates alternating magnetic poles, so that the permanent magnet generate suction torque and repulsive torque, or repulsive torque and suction torque, driving the rotary output component500to reciprocatively rotate, the corresponding mechanical units are thereby driven to reciprocatively rotate by the rotary output component500.

In the power-off state, the first and second permanent magnets410,420and the first support leg110form a closed magnetic path through the air gap, and the third and fourth permanent magnets430,440and the second leg120form a closed magnetic path through the air gap, to avoid magnetic leakage. Moreover, the permanent magnet and the second yoke300are mounted on the rotary output component500, so that other portions of the rotary output component500do not affect the magnetic field, that is, other portions of the rotary output component will not affect the magnetic circuits even if there is permeability magnetic material.

Further, the end faces111,121of the first support leg110and the support second leg120are inclined faces with an inclination angle of α, and the rotatory central line C of the rotary output component500is perpendicular to the inclined face.

The inclination angle α is shown inFIG. 4, which is an angle formed by the leg end face121and the vertical plane in the orientation shown inFIG. 4.

Further, the inclination angle range can be set to be 3°≤α≤8°. Similarly, as rotatory central line C of the rotary output component500is perpendicular to the inclined face, the rotary output component500is also inclined by 3-8°, which ensures that the electric toothbrush conforms with ergonomics when in use, and is convenient for user to clean mouth.

The U-shaped yoke100can be formed by stamping and laminating a silicon steel sheet, and then cutting into an inclined end surface by water cutting or laser cutting process.

Further, the gap between the first permanent magnet410and the second permanent magnet420may be smaller than the length of the end face111of the first support leg110in the direction in which the first permanent magnet410and the second permanent magnet420lie, and the gap between the third permanent magnet430and the fourth permanent magnet440may be smaller than the length of the end face121of the second leg120in the direction in which the third permanent magnet430and the fourth permanent magnet440lie. In order to ensure that the legs of the U-shaped yoke100have sufficient force for all the permanent magnets.

Referring toFIG. 5, taking the third permanent magnet430and the fourth permanent magnet440as an example, the gap between the third permanent magnet430and the fourth permanent magnet440refers to the distance L1 shown inFIG. 5, and the length of the end face of the second leg120in the direction in which the third permanent magnet430and the fourth permanent magnet440lie refers to the distance L2 shown inFIG. 5.

Referring toFIG. 1, the width between the first permanent magnet410, the second permanent magnet420, the third permanent magnet430, the fourth permanent magnet440and each other may be greater than the width between the first leg110and the second leg120, also for ensuring that the legs of the U-shaped yoke100have sufficient force for each permanent magnet. The width is the distance in the vertical direction shown inFIG. 1.

Referring toFIG. 1, the rotary output component500can include a rotating shaft that is rotatably mounted on a support body. As shown inFIG. 1, the support body may be a support bearing540, or may be other structures that can support the rotating shaft being rotatably mounted, such as a spring support structure.

The rotating shaft may be an integrally-formed shaft structure or it may be a combination of multiple parts. Referring toFIGS. 1 and 2, in the present embodiment, the rotating shaft includes a drive shaft511and an output shaft512, the drive shaft511and the output shaft512are fixedly connected by a coupling body513. This structure facilitates the addition of other structures on the rotating shaft and reduces the processing difficulty.

In addition, the drive motor further includes a resonance component. During the reciprocal rotation of the rotating shaft, the resonance component resonates with the rotating shaft to increase the rotational amplitude and the torque of the rotating shaft.

The resonance component may include a position limiter that rotates together with the rotating shaft and a resonator with elasticity, and the resonator is disposed on the reciprocal rotation trace of the position limiter, the position limiter causes the resonator to deform when reciprocatively rotating about the rotating shaft. The position limiter can be disposed on the coupling body to reduce the processing difficulty.

As shown inFIG. 6, two springs621are disposed in a mounting seat630. The position limiter611is a plate-like structure that presses the springs621as the rotating shaft510reciprocates, causing the springs621to resonate with the rotating shaft510. Thereby, the rotational amplitude and the torque of the rotating shaft510are further increased.

The rotating shaft510referred to herein is an illustration, its specific structure may be a combination of the drive shaft511, the output shaft512and the coupling body513, or may be an integrally-formed shaft structure.

As shown inFIG. 7, the springs622may also be fixed on a bottom plate631. The position limiter612is a two-plate structure, the two plates are disposed on two sides of the rotating shaft510and respectively press their corresponding springs622, they press the springs622when reciprocatively rotating about the rotating shaft510, causing the spring622to resonate with the rotating shaft510.

The resonance component may include a position limiter and a resonator with elasticity, the resonator rotates together with the rotating shaft, and position limiter limits the rotation of the resonator, causing the resonator to deform when rotating.

As shown inFIG. 8, the resonator is made of two spring plates623, which are disposed on two sides of the rotating shaft510, and the two position limiters613are respectively located below the corresponding spring plates623. When the spring plates623rotate together with the rotating shaft510, the position limiters613limit the rotation of the spring plates623, causing the spring plates623to deform when rotating, and resonate with the rotating shaft510.

As shown inFIG. 9, the resonator is made of one piece or two pieces of spring624, which is (are) disposed on one side or both sides of the rotating shaft510respectively, and a position limiter614is disposed on the support body or the housing. One end of the spring624is fixed to the coupling body513, and the other end is fixed to the position limiter614. When the spring(s)624rotate(s) together with the rotating shaft510, the position limiter614limits the rotation of the spring624, causing the spring624to deform when rotating, and resonate with the rotating shaft510.

Further, an elastic body for absorbing the moment of inertia of rotating shaft is disposed in the rotating direction of the rotating shaft, and the elastic characteristic of the elastic body is above quadratic curve, the elastic body is a sphere, an elliptical sphere, a cylinder, an elliptical cylinder, a semi-circular silicone or a rubber.

Specifically, referring toFIG. 10, a linkage710is fixed on the rotating shaft510. The linkage710is located between the two elastic bodies720. The position limiter rotates with the rotating shaft to press the elastic bodies720.

The elastic body720is mainly used for absorbing the moment of inertia of the rotary output component500under no-load condition. With the increase of the compression stroke, the elastic force is small before the position is reached, and it is rapidly increased when the position is fast. The elastic force increases with the compression stroke, and the elastic force is small before the position is reached. The elastic characteristics of the elastic body720can ensure that the elastic body720does not have excessive influence on the rotation of the rotary output component500under load (the rotation of the rotary output component500is attenuated under load). Only when the rotary output component500excessively presses the elastic bodies720under no-load condition will a large restoring force be generated.

Referring toFIG. 1, a rechargeable battery230and a charging module240may be further included. The rechargeable battery230is used for power supply, and the charging module240is connected to the control circuit for charging the rechargeable battery230.

The control circuit may further include a status indication module250for indicating operating state of the motor, and a switch for triggering a signal to the control circuit, to control the motor on and off.

Further, the control circuit220can determine the frequency of mechanical oscillations by counting the energization pulses of the coils, the output signal gives a corresponding indication to the operating condition of the mechanical unit.

In addition to driving the electric toothbrush, the drive motor shown in this embodiment can also drives various mechanical units that require reciprocating rotational motion.

The second embodiment provides an electric toothbrush.

The electric toothbrush comprises a drive motor and a brush head, the drive motor can output a reciprocating rotational motion to drive the brush head to reciprocate and oscillate, thereby achieving oral cleaning.

The drive motor can employ the drive motor structures shown in any of the above embodiments, wherein the brush head is mounted on the rotary output component500of the drive motor, for example, on the output shaft512.

The above is a further detailed description of the present disclosure combined with the specific embodiments, however, the specific embodiments of the present invention are not limited to the description. For those skilled in the art, several simple derivations or substitutions can be made without departing from the inventive concept.