阅读说明：本技术 线性振动马达 (Linear vibration motor ) 是由 郑锡焕 于 2019-07-11 设计创作，主要内容包括：根据本发明一个实施例的线性振动马达包括：壳体,其包括上部壳体和下部壳体,上部壳体的下部开放,下部壳体与所述上部壳体相结合,从而形成内部空间；定子,其在所述内部空间配置于所述下部壳体上；弹性部件,其在所述内部空间配置为包围所述定子的下部区域,一面与所述下部壳体相结合；振子,其包括环形磁铁,环形磁铁安装于所述弹性部件的另一面,并配置为包围所述定子；以及磁性流体,其涂覆于所述环形磁铁的上部,所述上部壳体包括环形凸出部,环形凸出部在与所述下部壳体相面对的内侧面具有比所述环形磁铁的外径大的内径。(A linear vibration motor according to an embodiment of the present invention includes: a case including an upper case, a lower case, and a lower case, the upper case having a lower portion opened, the lower case being combined with the upper case to form an inner space; a stator disposed in the lower case in the internal space; an elastic member disposed in the inner space so as to surround a lower region of the stator, one surface of the elastic member being bonded to the lower case; a vibrator including a ring magnet attached to the other surface of the elastic member and arranged to surround the stator; and a magnetic fluid applied to an upper portion of the ring magnet, the upper housing including an annular protrusion having an inner diameter larger than an outer diameter of the ring magnet at an inner side surface facing the lower housing.)

1. A linear vibration motor, comprising:

a case (20) including an upper case (20a) and a lower case (20b), the upper case (20a) having a lower portion opened, the lower case (20b) being combined with the upper case (20a) to form an inner space;

a stator (30) disposed in the lower case (20b) in the internal space;

an elastic member (40) disposed in the inner space so as to surround the stator (30) and bonded to the lower case (20 b);

a vibrator (50) including a ring magnet (52), the ring magnet (52) being attached to the other surface of the elastic member (40) and being arranged so as to surround the stator (30); and

a magnetic fluid (F) applied to an upper portion of the ring magnet (52),

the upper case (20a) further includes an annular projection (25), and the annular projection (25) has an inner diameter larger than an outer diameter of the annular magnet (52) on an inner side surface facing the lower case (520 b).

2. The linear vibration motor according to claim 1,

the annular projection (25) has the same shape as the annular magnet (52).

3. The linear vibration motor according to claim 1,

the vibrator (50) includes:

an annular weight (54) configured to surround the annular magnet (52); and

an annular yoke (56) disposed between the annular weight body (54) and the annular magnet (52),

the annular projection (25) has an inner diameter larger than an outer diameter of the annular yoke (56).

4. The linear vibration motor according to claim 1,

the annular projection (25) is an annular projection member (R),

the annular projecting member (R) is attached to an inner side surface of the upper case (20a) facing the lower case (20 b).

5. The linear vibration motor according to claim 4,

the annular protrusion member (R) is formed of a soft material softer than the upper case (20a) or a hard material harder than the upper case (20 a).

6. The linear vibration motor according to claim 1,

the annular protrusion (25) is an annular groove (H) recessed in a lower direction from an outer side surface of the upper housing (20 a).

7. The linear vibration motor according to claim 1,

the upper case (20a) further includes a buffer portion (60), and the buffer portion (60) has a diameter larger than the inner diameter of the ring magnet (52) or the same as the inner diameter of the ring magnet (52) on the inner side surface of the upper case (20a) facing the lower case (20b), and has a diameter smaller than the inner diameter of the ring-shaped protrusion (25) or the same as the inner diameter of the ring-shaped protrusion (25).

8. The linear vibration motor according to claim 7,

the buffer part (60) is a flat-plate-type buffer member (P) attached to an inner side surface of the upper case (20a) facing the lower case (20 b).

9. The linear vibration motor of claim 8,

the plate-shaped buffer member (P) is a soft material softer than the upper case (20a) or a hard material harder than the upper case (20 a).

10. The linear vibration motor according to claim 7,

the buffer part (60) is a flat groove (H') recessed from the outer surface of the upper case (20a) in the lower direction.

Technical Field

The present invention relates to a linear vibration motor. And more particularly, to a linear vibration motor having a structure such that noise generated during the operation of the vibration motor is reduced.

Background

In general, a mobile terminal such as a mobile phone is provided with a vibration function (tactile) of an interface such as call forwarding and an interface for feedback to a user regarding key input, event occurrence, application execution, and the like.

The vibration motor embodying such a vibration function is a device that converts electromagnetic force into mechanical drive to generate vibration, and can be roughly classified into a flat/coin type vibration motor and a linear type vibration motor according to a driving method and a driving form.

In the case of the flat-type vibration motor, the vibration generated by the rotation of the internal mass body has a feature of remaining by the inertia of the rotation, and a linear vibration motor having no inertia of the rotation is mainly used for a device requiring a rapid response speed.

In addition, the linear vibration motor is designed to have a characteristic that an electromagnetic force generated by means of the coil and the magnet and a physical elastic force provided by the elastic member resonate with each other, and if a power source of a specific frequency having a variable characteristic is applied to the coil so that the electromagnetic force is generated, the generated electromagnetic force and a magnetic force of the magnet interact with each other, so that the vibrator vibrates in the up-down direction while being supported by the elastic force of the elastic member.

However, when the vibration intensity increases during the vertical vibration of the vibrator of the linear vibration motor, there are problems as follows: the efficiency of the linear vibration motor is reduced by generating vibration noise (noise) due to the internal contact of the vibrator. As a countermeasure for this, a method of applying a magnetic fluid to one side of a vibrator is disclosed, but in terms of physical properties of the magnetic fluid, if a linear vibration motor is used for a long time, the magnetic fluid diffuses, and there is a problem that a function of relaxing impact or reducing noise cannot be normally performed.

Thus, a new structure that can secure the reliability of the linear vibration motor by preventing the movement of the magnetic fluid within the linear vibration motor is required. The present invention is concerned with this.

Disclosure of Invention

The technical problem to be solved by the present invention is to prevent the magnetic fluid applied to the vibrator from moving in the linear vibration motor.

Another technical problem to be solved by the present invention is to ensure the operational reliability of the linear vibration motor.

The technical problem of the present invention is not limited to the above-mentioned technical problem, and other technical problems can be clearly found by those skilled in the art from the following descriptions.

A linear vibration motor according to an embodiment of the present invention is characterized by comprising: a case including an upper case, a lower case, and a lower case, the upper case having a lower portion opened, the lower case being combined with the upper case to form an inner space; a stator disposed in the lower case in the internal space; an elastic member disposed in the inner space so as to surround the stator, one surface of the elastic member being bonded to the lower case; a vibrator including a ring magnet attached to the other surface of the elastic member and arranged to surround the stator; and a magnetic fluid applied to an upper portion of the ring magnet, the upper case further including an annular protrusion on an inner side surface facing the lower case, the annular protrusion having an inner diameter larger than an outer diameter of the ring magnet.

According to one embodiment, the annular protrusion may have the same shape as the ring magnet.

According to one embodiment, the vibrator includes: an annular weight body configured to surround the annular magnet so that vibration is amplified; and an annular yoke forming a closed magnetic path between the annular weight and the annular magnet, the annular protrusion having an inner diameter equal to or greater than an outer diameter of the annular yoke.

According to one embodiment, the annular projection is an annular projection member attachable to an inner side surface of the upper housing facing the lower housing.

According to one embodiment, the annular protruding member may be formed of a soft material softer than the upper case or a hard material harder than the upper case.

According to one embodiment, the annular protrusion may be an annular groove recessed in a lower direction from an outer side surface of the upper housing.

According to one embodiment, the upper case further includes a buffer portion having a diameter larger than or the same as an inner diameter of the ring magnet at an inner side surface of the upper case facing the lower case, and having a diameter smaller than or the same as an inner diameter of the ring protrusion.

According to one embodiment, the buffer part is a flat plate type buffer member attached to an inner side surface of the upper case facing the lower case.

According to one embodiment, the plate type buffer member may be formed of a soft material softer than the upper case or a hard material harder than the upper case.

According to one embodiment, the buffer part may be a flat groove depressed in a lower direction from an outer side surface of the upper case.

According to the present invention, the movement of the magnetic fluid in the linear vibration motor can be physically prevented.

In addition, in the process of the vibrator vibration of the linear vibration motor, the physical collision applied to the inside of the housing can be prevented, and the noise generation caused by the vertical vibration can be reduced.

Further, even if the linear vibration motor is used for a long time, the vibrator generates a constant vibration, so that the reliability of the linear vibration motor can be maintained.

The effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood by those skilled in the art from the following description.

Drawings

Fig. 1a is a diagram showing a moving shape of a magnetic fluid in a conventional linear vibration motor.

Fig. 1b is a photograph of a magnetic fluid moving by vibration of a conventional linear vibration motor.

Fig. 2a is a view showing the structure of a linear vibration motor according to a first embodiment of the present invention.

Fig. 2b is a perspective view of a ring-shaped protrusion according to the first embodiment of the present invention.

Fig. 3a is a view showing the structure of a linear vibration motor according to a second embodiment of the present invention.

Fig. 3b is a perspective view of an upper housing including an annular projection according to a second embodiment of the present invention.

Fig. 4 is a view showing the structure of a linear vibration motor according to a third embodiment of the present invention.

Fig. 5a is a view showing the structure of a linear vibration motor according to a fourth embodiment of the present invention.

Fig. 5b is a perspective view of an upper case including a cushioning portion according to a fourth embodiment of the present invention.

Fig. 6a is a view showing a moving shape of a magnetic fluid in a linear vibration motor according to a third embodiment of the present invention.

Fig. 6b is a photo of a real object in which the magnetic fluid is moved due to the vibration of the linear vibration motor according to the third embodiment of the present invention.

Description of the reference symbols

1: conventional linear vibration motor

100: linear vibration motor

10: substrate

20: shell body

20 a: upper shell

20 b: lower casing

25: annular projection

30: stator

32: coil

34: coil yoke

40: elastic component

50: vibrator

52: ring magnet

54: ring-shaped weight

56: annular yoke

60: buffer part

F: magnetic fluid

Detailed Description

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Throughout the description, the same reference numerals denote the same constituent elements. The advantages, features and methods of accomplishing the same may be understood by reference to the embodiments described in detail herein, taken in conjunction with the accompanying drawings. However, the present invention can be realized in various forms including various combinations of many constituent elements described in the embodiments described below, and therefore, the described embodiments are provided only for understanding the present invention, and the scope of the present invention is not intended to be limited to the embodiments.

Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used as meanings commonly understood by one of ordinary skill in the art to which the present invention belongs. In addition, terms defined in commonly used dictionaries should not be interpreted ideally or excessively unless explicitly and specifically defined. The terminology used in the description is for the purpose of describing embodiments only and is not intended to be limiting of the invention. In this specification, the singular also includes the plural as long as it is not specifically mentioned in the sentence.

As used herein, "comprising" and/or "comprising …" refers to a component, step, operation, and/or element that does not preclude the presence or addition of one or more other components, steps, operations, and/or elements.

Fig. 1a is a diagram showing a moving state of a magnetic fluid 6 in a conventional linear vibration motor 1. Fig. 1b is a photograph of a magnetic fluid 6 moving by vibration of a conventional linear vibration motor 1.

Referring to fig. 1a, a conventional linear vibration motor 1 includes a housing 2, a stator 3, an elastic member 4, a vibrator 5, a magnetic fluid 6, and a substrate 7. When an electromagnetic force is generated by supplying a current to the stator 3 through the substrate 7, the electromagnetic force interacts with the vibrator 5 disposed around the stator 3 to generate vibration, and the vibration is supported by the elastic force of the elastic member 4 and vibrates vertically. At this time, in order to prevent the vibrator 5 vibrating up and down from directly colliding against the case 2, the magnetic fluid 6 is applied to the upper surface of the magnet 5a, but the magnetic fluid 6 colliding against the case 2 is diffused while the vibrator 5 vibrates upward, and thus there is a problem in that the original collision prevention function cannot be normally performed.

Referring to fig. 1b, in the case of using the linear vibration motor 1 of the conventional structure for a long time, it was confirmed that the magnetic fluid 6 was diffused to the edge of the case 2 in a ring shape indicated by oblique lines. The magnetic fluid 6 in such a state cannot perform the collision prevention function, and as a result, the reliability of the linear vibration motor 1 is lowered.

Fig. 2a is a view showing the structure of a linear vibration motor 100 according to a first embodiment of the present invention, and fig. 2b is a perspective view of a ring-shaped protrusion 25 according to the first embodiment of the present invention.

Referring to fig. 2a, the linear vibration motor 100 includes a substrate 10, a case 20, a stator 30, an elastic member 40, a vibrator 50, and a magnetic fluid F.

The housing 20 includes an upper housing 20a having an open lower portion and a lower housing 20b combined with the upper housing 20a to form an inner space. The lower case 20a may be an acoustic diaphragm, and may generate sound by vibrating by electromagnetic force of the stator 30.

The substrate 10 is disposed below the linear vibration motor 100, and a partial region may be exposed to the outside of the linear vibration motor 100 in order to receive power from the outside. In addition, the substrate 10 may supply power applied from the outside to the stator 30.

The case 20 may have a cylindrical shape, but is not limited thereto, and may have a square tube (pillar) or polygonal tube shape, and the substrate 10 coupled to the case 20, the elastic member 40 and the vibrator 50 housed in the case 20 may have the same rectangular shape or a variable shape.

The stator 30 is disposed in the lower case 20b in an inner space formed by the case 20, and may include a coil 32 and a coil yoke 34. According to an embodiment, the coil 32 may be an acoustic coil that generates magnetic fields of different directions and strengths. More specifically, if an alternating current is applied to the coil 32 through the substrate 10, an alternating magnetic field is generated at the coil 32, so that the lower case 20b in contact with the coil 32 vibrates by a signal of an audible frequency region, thereby generating sound.

The coil yoke 34 is disposed in parallel with the coil 32, and can strengthen the magnetic force generated in the coil 32.

The elastic member 40 is disposed in the lower case 20b so as to surround the stator 30 in the inner space formed by the case 20, and supports the vibrator 50.

One surface of the elastic member 40 may be fixed to the lower case 20b, and the other surface may be coupled to the vibrator 50, thereby supporting the vibrator 50. The elastic member 40 may be formed in a shape having a diameter that decreases from the lower side to the upper side, and may amplify the vertical vibration of the vibrator 50 by an elastic force.

The vibrator 50 may include a ring magnet 52, a ring weight 54, and a ring yoke 56, and is mounted on the elastic member 40 in an inner space formed by the case 20 so as to surround the stator 30. If an alternating current is applied to the stator 30 from the substrate 10, vibration may be performed by interaction with a magnetic force generated at the stator 30.

In addition, although one ring magnet 52 is shown in fig. 2a, more than two ring magnets 52 may be combined to generate a stronger magnetic force.

The weight 54 of the vibrator 50 may be disposed along the circumference of the ring magnet 52 with a predetermined interval from the ring magnet 52, thereby amplifying the vertical vibration of the ring magnet 52. Further, the outer diameter of the ring-shaped weight body 54 is formed smaller than the inner diameter of the case 20, so that it can be prevented from contacting the case 20 in the process of the vibrator 50 as a whole performing up-down vibration, whereby the reliability of the linear vibration motor 100 can be secured.

The ring yoke 56 of the vibrator 50 is disposed between the ring magnet 52 and the ring weight 54, and can be in contact with the ring magnet 52 and the ring weight 54. The annular yoke 56 contributes to the formation of a closed magnetic circuit for smoothing the flow of the magnetic field generated at the annular magnet 52.

The magnet 52 is coated with a magnetic fluid F for preventing physical collision with the case 20 when the vibrator 50 vibrates up and down, so that noise generation due to vibration of the linear vibration motor 100 can be suppressed.

The annular protrusion 25 of the inner surface of the upper case 20a serves to maintain the magnetic fluid F applied to the upper portion of the ring magnet 52 in an original state without change even if the linear vibration motor 100 is driven for a long time. More specifically, the annular protrusion 25 may be formed at an inner side surface of the upper case 20a facing the lower case 20b, and an inner diameter D1 of the annular protrusion 25 may have a larger value than an outer diameter D2 of the ring magnet 52. The annular protrusion 25 prevents the magnetic fluid F coated on the upper portion of the ring magnet 52 from moving.

Referring to fig. 2b, the annular protrusion 25 may be in the form of an annular protrusion R that may be attached to an inner side surface of the upper case 20a facing the lower case 20 b.

Further, the annular protrusion member R may be formed of a soft material that is not harder than the upper case 20a as plastic so as to maintain the coating form of the magnetic fluid F, and may be formed of a hard material that is harder than the upper case 20a as brass or stainless steel so as to more reliably prevent the magnetic fluid F from moving to the outer side surface of the annular protrusion portion 25.

The structure of the linear vibration motor 100 for preventing the magnetic fluid F from moving according to the first embodiment of the present invention has been described so far, and another structure of the annular protrusion 25 formed at the housing 20 is described below.

Fig. 3a is a view showing the structure of a linear vibration motor 100 according to a second embodiment of the present invention, and fig. 3b is a perspective view of an upper housing 20a including an annular protrusion 25 according to the second embodiment of the present invention.

In describing the structure of the linear vibration motor 100, only the different components from the linear vibration motor 100 shown and described in fig. 2a will be described with reference to fig. 3 a. In other words, the linear vibration motor 100 shown in fig. 3a is different only in the configuration of the annular protrusion 25 compared to the linear vibration motor 100 shown in fig. 2a, and thus only this will be explained.

The annular protrusion 25 shown in fig. 3a and 3b is formed in the form of an annular groove H recessed in the lower direction from the outer surface of the upper case 20a, instead of the form in which the annular protrusion member R is attached to the upper case 20 a. The annular protrusion 25 as described above may be obtained by forming the annular groove H having a diameter smaller than the outer diameter D2 of the ring magnet 52 during injection molding of the upper housing 20 a.

In addition, in consideration of the mobility of the magnetic fluid F applied to the upper portion of the ring magnet 52, the minimum inner diameter D1' of the annular groove a formed at the outer side surface of the upper case 20a and the minimum inner diameter D1 of the annular protrusion R attached to the inner side surface of the upper case 20a may be formed to be the same as the outer diameter D3 of the annular yoke 56.

In the explanation of fig. 2 and 3, the annular protrusion 25 has been described as having a circular shape, but may have a polygonal shape without being limited thereto. However, in order to more firmly prevent the magnetic fluid F coated on the upper portion of the ring magnet 52 from moving, it is preferable that the annular protrusion 25 has the same shape as the ring magnet 52.

The structure of the annular protrusion 25 according to the first and second embodiments of the present invention has been described so far, and the structure of the linear vibration motor 100 capable of preventing the magnetic fluid F from moving, except for the annular protrusion 25, will be described below.

Fig. 4 is a diagram showing the structure of a linear vibration motor 100 according to a third embodiment of the present invention.

Referring to fig. 4, a buffer portion 60 is provided on the inner side surface of the upper case 20a including the annular protrusion 25. More specifically, the buffer portion 60 is formed at the inner side surface of the upper case 20a facing the lower case 20b, and the diameter D5 of the buffer portion 60 may have a value greater than the inner diameter D4 of the ring magnet 52 and smaller than the inner diameter D1 of the ring protrusion 25. The buffer portion 60 serves to maintain the magnetic fluid F applied to the upper portion of the ring magnet 52 in a circular state without change even if the linear vibration motor 100 is driven for a long time.

The buffer portion 60 may be in the form of a flat plate-type buffer member P, and the flat plate-type buffer member P may be attached to an inner surface of the upper case 20a facing the lower case 20 b. Further, the plate-type buffer member P may be formed of a soft material that is not harder than the upper case 20a as plastic so as to maintain the coating form of the magnetic fluid F, and may be formed of a hard material that is harder than the upper case 20a as brass or stainless steel so as to more reliably prevent the magnetic fluid F from moving toward the center of the linear vibration motor 100.

The structure of the linear vibration motor 100 for preventing the magnetic fluid F from moving according to the third embodiment of the present invention has been described so far, and another structure of the buffer portion 60 formed at the upper case 20a is described below.

Fig. 5a is a view showing the structure of a linear vibration motor 100 according to a fourth embodiment of the present invention, and fig. 5b is a perspective view of an upper case 20a including a buffer 60 according to the fourth embodiment of the present invention.

Referring to fig. 5a and 5b, the buffer part 60 according to the fourth embodiment is formed in a flat-plate type groove H' form recessed in the lower direction from the outer surface of the upper case 20a, instead of the form in which the flat-plate type buffer member P is attached to the upper case 20 a. For this reason, in the process of injecting the upper case 20a, a flat plate type groove H' having a diameter smaller than the outer diameter D2 of the ring magnet 52 may be formed.

In consideration of the mobility of the magnetic fluid F applied to the upper portion of the ring magnet 52, the minimum diameter D5 'of the flat-plate type groove H' formed at the outer side surface of the upper case 20a and the minimum diameter D5 of the flat-plate type buffer member P attached to the inner side surface of the upper case 20a may be formed to be the same as the outer diameter D6 of the stator 30 disposed to surround the support shaft a of the lower case 20 b.

In the description of the linear vibration motor 100 according to the embodiment of fig. 4 and 5, the case where the annular protrusion member R and the plate-shaped buffer member P are disposed in the upper case 20a of one linear vibration motor 100, or the case where the annular groove H and the plate-shaped groove H' are disposed in the upper case 20a of one linear vibration motor 100 is exemplified, but the present invention is not limited thereto, and the protrusion shape and the groove shape may be disposed to intersect each other.

The structure of the buffer 60 according to the third and fourth embodiments has been described so far, and the internal structure of the linear vibration motor 100, which changes when the linear vibration motor 100 of the present invention is used, will be described below.

Fig. 6a is a diagram showing a moving shape of the magnetic fluid F in the linear vibration motor 100 according to the third embodiment of the present invention, and fig. 6b is a physical photograph in which the magnetic fluid F moves due to the vibration of the linear vibration motor 100 according to the third embodiment of the present invention.

Referring to fig. 6a, in the process of vertically vibrating the vibrator 50 in the linear vibration motor 100, the magnetic fluid F applied to the upper portion of the ring magnet 52 must directly collide with the upper case 20a and spread from the upper portion of the ring magnet 52 to the periphery, but the magnetic fluid F moves only within a range not departing from the space S between the ring protrusion 25 and the buffer 60 by means of the ring protrusion 25 and the buffer 60 disposed on the inner surface of the upper case 20 a. Accordingly, the magnetic fluid F can be fixed without being separated from the original position, that is, without being separated from the upper portion of the ring magnet 52, while the linear vibration motor 100 is continuously driven.

Referring to fig. 6b, even if the linear vibration motor 100 of the present invention is used for a long time, the magnetic fluid F is not diffused to the edge of the upper case 20a due to the annular protrusion 25 and the buffer 60, and it is confirmed that the original position is maintained.

As described above, the linear vibration motor 100 of the present invention places the annular protrusion 25 and the buffer 60 inside the upper case 20a, so that the magnetic fluid F is maintained at its original position even if the linear vibration motor 100 is used for a long time, thereby preventing direct collision with the case of the vibrator 50, and thus maintaining the reliability of the linear vibration motor 100.

While the embodiments of the present invention have been described with reference to the drawings, it is to be understood that those skilled in the art to which the present invention pertains may implement various embodiments without changing the technical spirit or essential features of the present invention. It should therefore be understood that the above-described embodiments are illustrative in all respects and not restrictive.