CN109068244B

CN109068244B - Electromagnetic exciter and screen sounding device

Info

Publication number: CN109068244B
Application number: CN201810785552.6A
Authority: CN
Inventors: 祖峰磊; 杨鑫峰
Original assignee: Goertek Inc
Current assignee: Goertek Inc
Priority date: 2018-07-17
Filing date: 2018-07-17
Publication date: 2020-03-17
Anticipated expiration: 2038-07-17
Also published as: WO2020015472A1; CN109068244A

Abstract

The invention discloses an electromagnetic exciter and a screen sounding device. The exciter comprises a shell, a vibrator assembly and a stator assembly, wherein the stator assembly and the vibrator assembly are accommodated in the shell, the vibrator assembly is suspended in the shell through an elastic element, the vibrator assembly comprises a coil and a core column arranged in the coil, the vibrator assembly is located in a magnetic field of the stator assembly, and the stator assembly comprises a Halbach permanent magnet array.

Description

Electromagnetic exciter and screen sounding device

Technical Field

The invention relates to the technical field of electroacoustic conversion, in particular to an electromagnetic exciter and a screen sounding device.

Background

In order to increase the screen area ratio (i.e. the ratio of the screen area to the front area) of electronic products such as mobile phones, it is a development trend to eliminate earphones. In some versions, a screen sound device is used in place of the earpiece. A screen sound emitting device generally includes a screen body and an electromagnetic exciter disposed on the screen body. The electromagnetic exciter vibrates, so that the screen body is driven to vibrate to make sound.

The existing electromagnetic exciter generally comprises a stator, a vibrator and a housing. The stator includes a coil. The vibrator comprises a permanent magnet and a mass block which are connected together. The oscillator is suspended in the cavity of the shell through the elastic sheet. The coil is fixed on the inner wall of the shell.

However, such an electromagnetic actuator has a low magnetic field utilization rate and a small driving force.

In addition, the driving force changes along with the displacement of the vibrator in a nonlinear way, so that the vibration is not stable, and the radiated sound distortion is large.

In addition, the stator is fixed, and the heat dissipation of the coil is poor, so that the electromagnetic exciter generates heat seriously.

Therefore, a new technical solution is needed to solve the above technical problems.

Disclosure of Invention

It is an object of the present invention to provide a new solution for an electromagnetic actuator.

According to a first aspect of the present invention, an electromagnetic exciter is provided. The exciter comprises a shell, a vibrator assembly and a stator assembly, wherein the stator assembly and the vibrator assembly are accommodated in the shell, the vibrator assembly is suspended in the shell through an elastic element, the vibrator assembly comprises a coil and a core column arranged in the coil, the vibrator assembly is located in a magnetic field of the stator assembly, and the stator assembly comprises a Halbach permanent magnet array.

Optionally, the halbach permanent magnet array includes a first permanent magnet, a second permanent magnet, and a third permanent magnet that are arranged in parallel along the vibration direction; the first permanent magnet and the third permanent magnet are oppositely magnetized, the magnetizing direction is parallel to the vibration direction, and the magnetizing direction of the second permanent magnet points to the coil.

Optionally, the coil is in a rectangular ring shape or a racetrack ring shape, and the first permanent magnet, the second permanent magnet, and the third permanent magnet are opposite to the long side of the coil.

Optionally, the permanent magnet device further comprises a fourth permanent magnet and a fifth permanent magnet which are arranged at two ends of the second permanent magnet along the long axis direction, and the fourth permanent magnet and the fifth permanent magnet are oppositely magnetized.

Optionally, the core column includes a sixth permanent magnet and a seventh permanent magnet that are arranged in parallel along the vibration direction, and the magnetizing directions of the sixth permanent magnet and the seventh permanent magnet are opposite to each other.

Optionally, the core column includes an eighth permanent magnet and a ninth permanent magnet that are arranged in parallel perpendicular to the vibration direction, and the eighth permanent magnet and the ninth permanent magnet are oppositely magnetized.

Optionally, the elastic element includes an elastic piece, the elastic piece includes a first connection portion, a second connection portion, and an elastic arm portion located between the first connection portion and the second connection portion, the first connection portion is connected to the housing, and the second connection portion is connected to the vibrator component.

Optionally, the housing and the resilient tab form an integral structure.

Optionally, the elastic pieces are multiple and respectively located at the upper side and the lower side of the vibrator assembly along the vibration direction; or the elastic sheets are positioned on the same side of the vibrator assembly along the vibration direction.

Optionally, the spring arm portion is linear or V-shaped.

Optionally, a boss protruding into the cavity is formed on a wall of the housing, and the first connecting portion is fixed to the boss to form a gap between the spring arm portion and the wall.

Optionally, the housing is made of magnetically permeable material.

According to another aspect of the present invention, there is provided a screen sound emitting apparatus. The device comprises a screen body, a middle frame and the electromagnetic exciter provided by the invention, wherein the electromagnetic exciter is arranged on the screen body or the middle frame.

Optionally, the screen further comprises foam rubber, and the electromagnetic exciter is fixedly connected with the screen body or the middle frame through the foam rubber; or the electromagnetic exciter is connected with the screen body or the middle frame through a bolt.

According to one embodiment of the present disclosure, a vibrator assembly includes a coil and a stem. The coil vibrates under the action of ampere force in the magnetic field of the stator assembly in response to the electrical signal of the external circuit. The core column can increase the inertia of the oscillator and improve the amplitude.

In addition, halbach arrays of permanent magnets focus the magnetic field more. According to ampere's law, under the set input current, the force that the coil received is bigger to the transduction efficiency of electromagnetic actuator has been promoted.

In addition, the ampere force received by the vibrator assembly in the vibration process is more uniform, the nonlinear phenomenon generated by the change of the driving force of the existing structure along with the displacement is avoided, the vibration is more stable, and the radiated sound distortion is further reduced.

In addition, the coil vibrates, heat can be effectively dissipated, and due to the blocking effect of air, the heat of the coil is difficult to transfer to the shell, so that the indicating temperature of the electromagnetic exciter is lower, and the screen with higher loudness is facilitated to sound.

Other features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments thereof, which proceeds with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.

Fig. 1 is a schematic structural view of a stator assembly and a vibrator assembly according to an embodiment of the present invention.

Figure 2 is a side view of a stator assembly according to one embodiment of the present invention.

Figure 3 is a side view of another stator assembly according to one embodiment of the present invention.

Fig. 4 is a cross-sectional view of an electromagnetic exciter along a short axis according to one embodiment of the present invention.

Fig. 5 is a cross-sectional view of another electromagnetic actuator along a short axis according to an embodiment of the present invention.

Fig. 6 is a cross-sectional view of an electromagnetic exciter along a long axis according to one embodiment of the present invention.

Fig. 7 is a cross-sectional view of another electromagnetic actuator along a long axis, in accordance with an embodiment of the present invention.

Fig. 8 is a top view of an electromagnetic exciter according to one embodiment of the present invention.

Description of reference numerals:

11: a first permanent magnet; 12: a second permanent magnet; 13: a third permanent magnet; 14: a fourth permanent magnet; 15: a fifth permanent magnet; 16: a sixth permanent magnet; 17: a seventh permanent magnet; 18: an eighth permanent magnet; 19: a ninth permanent magnet; 20: a coil; 21: a magnetizer; 22: a housing; 23: a spring plate; 24: a spring arm portion; 25: a first connection portion; 26: a second connecting portion; 27: a stator assembly; 28: a vibrator assembly.

Detailed Description

Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.

The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.

In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

According to an embodiment of the present invention, there is provided an electromagnetic exciter. The electromagnetic exciter is for a screen sound emitting device and includes a housing 22, a vibrator assembly 28 and a stator assembly 27.

As shown in fig. 4-8, the stator assembly 27 and the vibrator assembly 28 are housed within the housing 22. The interior of the housing 22 forms a cavity. The stator assembly 27 and the vibrator assembly 28 are located in the cavity. For example, the housing 22 has a rectangular parallelepiped structure.

Preferably, the housing 22 is fabricated from a magnetically conductive material, such as iron, cobalt, nickel, low carbon steel, and the like. Therefore, on one hand, the gathering effect of the magnetic field can be enhanced, the magnetic induction strength is improved, on the other hand, the magnetic shielding effect is good, and the magnetic field of the stator assembly 27 cannot influence an external magnetic sensitive device.

The vibrator assembly 28 is suspended within the housing 22 by a resilient element. The elastic element may be, but is not limited to, a spring plate 23, a spring, or an elastic rubber member. The vibrator assembly 28 includes a coil 20 and a stem disposed within the coil 20. The vibrator assembly 28 is located in the magnetic field of the stator assembly 27. Preferably, the core is a magnetizer 21. For example, the magnetic conductor 21 is made of iron, cobalt, nickel, low-carbon steel, SPCC, or the like. The magnetizer 21 can guide more magnetic lines of force to pass through the coil 20, thereby improving the magnetic induction strength at the coil 20 and enhancing the driving force of the vibrator assembly 28.

The stator assembly 27 includes an array of halbach permanent magnets. The Halbach permanent magnet array is an array structure formed by assembling a plurality of permanent magnets in different magnetizing directions according to a set combination mode. The structure enables the magnetic induction lines to be gathered at a set part more, improves the magnetic induction intensity of the part, and can effectively reduce the magnetic induction intensity of other parts. In this way, the magnetic field utilization rate is effectively improved.

In an embodiment of the present invention, the vibrator assembly 28 includes the coil 20 and the stem. The coil 20 vibrates under the influence of an ampere force in the magnetic field of the stator assembly 27 in response to an electrical signal of an external circuit. The core column can increase the inertia of the oscillator and improve the amplitude.

In addition, halbach arrays of permanent magnets focus the magnetic field more. According to ampere's law, the coil 20 is subjected to a larger force at a set input current, thereby improving the transduction efficiency of the electromagnetic actuator.

In addition, the ampere force applied to the vibrator assembly 28 during vibration is more uniform, so that the nonlinear phenomenon caused by the change of the driving force of the existing structure along with the displacement is avoided, the vibration of the vibrator assembly is more stable, and the distortion of radiated sound is further reduced.

In addition, the coil 20 vibrates, heat can be effectively dissipated, and due to the blocking effect of air, the heat of the coil 20 is difficult to transfer to the shell 22, so that the surface temperature of the electromagnetic exciter is lower, and the screen with higher loudness can be sounded.

In one example, a magnetic conductive plate is disposed on one end surface of the coil 20 in the vibration direction, and the magnetic conductive plate can gather magnetic induction lines to further improve the magnetic induction strength at the coil 20. The vibration direction is shown as a in fig. 5.

In addition, the magnetic conduction plate can also play a role in connection and is used for being connected with the elastic element.

In one example, as shown in fig. 2, the halbach permanent magnet array includes a first permanent magnet 11, a second permanent magnet 12, and a third permanent magnet 13 that are juxtaposed in the vibration direction. The first permanent magnet 11, the second permanent magnet 12, and the third permanent magnet 13 are disposed in pairs on both sides of the coil 20. The first permanent magnet 11 and the third permanent magnet 13 are oppositely magnetized, and the magnetizing direction is parallel to the vibration direction. The magnetizing directions of the first permanent magnet 11 and the third permanent magnet 13 are directed to the second permanent magnet 12. Pointing towards the second permanent magnet 12, i.e. the N pole, is close to the second permanent magnet 12. The direction of magnetization of the second permanent magnet 12 is directed towards the coil 20, i.e. N is close to the coil 20. In this structure, the first permanent magnet 11, the second permanent magnet 12, and the third permanent magnet 13 collectively form a set magnetic circuit according to the respective magnetizing directions, and the magnetic fields of the three permanent magnets are concentrated more effectively, which enables the magnetic induction intensity at the coil 20 to be significantly improved.

In one example, as shown in fig. 1, the coil 20 has a rectangular ring shape or a race-type ring shape. The first permanent magnet 11, the second permanent magnet 12, and the third permanent magnet 13 are opposite to the long sides of the coil 20. The long side is a side of which the length of the coil 20 is long in an orthogonal projection of the surface perpendicular to the vibration direction. For example, two long sides of the rectangular ring shape, and two straight sides of the racetrack ring shape. The long side has a longer length, and this arrangement makes the driving force of the vibrator assembly 28 greater than the arrangement of the first permanent magnet 11, the second permanent magnet 12, and the third permanent magnet 13 on the other sides.

In one example, as shown in fig. 3, the stator holder further includes fourth and fifth

permanent magnets

14 and 15 disposed at both ends of the second permanent magnet 12 in the long axis direction. The major axis direction is parallel to the long side of the coil 20, the minor axis is perpendicular to the long side of the coil 20, and both the major axis and the minor axis are perpendicular to the vibration direction. The fourth permanent magnet 14 and the fifth permanent magnet 15 are oppositely magnetized, that is, the N poles of the two permanent magnets are close to each other. In this way, the magnetic field directions of the permanent magnets from the up, down, left, and right directions of the second permanent magnet 12 are all directed toward the second permanent magnet 12. This makes the magnetic induction lines of a plurality of permanent magnets gather to a higher degree, effectively improves the magnetic field at coil 20, improves the magnetic field utilization ratio, and improves the driving force of the oscillator.

Furthermore, the stator assembly 27 occupies a small space, facilitating a compact design of the electromagnetic exciter.

In one example, as shown in fig. 4, the stem includes a sixth permanent magnet 16 and a seventh permanent magnet 17 juxtaposed in the vibration direction. The sixth permanent magnet 16 and the seventh permanent magnet 17 are opposite in magnetizing direction, i.e., the S poles of the two permanent magnets are close to each other, and the N poles are far away from each other. For example, the sixth permanent magnet 16 and the seventh permanent magnet 17 are both bar magnets, and the thickness direction is parallel to the vibration direction.

When the height of the vibrator assembly 28 is high, the magnetizing directions of the sixth and seventh

permanent magnets

16 and 17 correspond to the magnetic circuit of the halbach permanent magnet array. The sixth permanent magnet 16 and the seventh permanent magnet 17 can gather magnetic induction lines after passing through the coil 20.

In addition, the magnetizing directions of the sixth permanent magnet 16 and the seventh permanent magnet 17 are along the magnetic field formed by the stator assembly 27, so that the magnetic induction strength at the coil 20 is further improved, and the driving force of the vibrator assembly 28 is improved.

In one example, as shown in fig. 5, the stem includes an eighth permanent magnet 18 and a ninth permanent magnet 19 juxtaposed perpendicular to the vibration direction. The eighth permanent magnet 18 and the ninth permanent magnet 19 are oppositely charged, i.e. the N poles of the two permanent magnets are close to each other. For example, the eighth permanent magnet 18 and the ninth permanent magnet 19 are both bar magnets, and the thickness direction is perpendicular to the vibration direction.

The magnetizing directions of the eighth permanent magnet 18 and the ninth permanent magnet 19 are the same as those of the second permanent magnet 12 which is close to each other. In this way, due to the orientation of the magnetic fields of the eighth permanent magnet 18 and the ninth permanent magnet 19, the magnetic induction line of the second permanent magnet 12 can be kept perpendicular to the coil 20 after passing through the coil 20, rather than being inclined, and the direction of the ampere force received by the coil 20 is more consistent according to the ampere rule, thereby improving the reliability of the vibration.

In addition, the eighth permanent magnet 18 and the ninth permanent magnet 19 can further gather magnetic induction lines, and the magnetic induction strength at the coil 20 can be improved.

In addition, the magnetizing directions of the eighth permanent magnet 18 and the ninth permanent magnet 19 are along the magnetic field formed by the stator assembly 27, so that the magnetic induction strength at the coil 20 is further improved, and the driving force of the vibrator assembly 28 is improved.

In one example, as shown in fig. 6-7, the resilient element comprises a spring plate 23. The spring plate 23 includes a first connecting portion 25, a second connecting portion 26, and a spring arm portion 24 located between the first connecting portion 25 and the second connecting portion 26. The first connection portion 25 is connected to the case 22, and the second connection portion 26 is connected to the vibrator assembly 28. For example, the connection is made by welding, bonding, riveting, or the like.

For example, as shown in fig. 6, the first connection portion 25 is parallel to the second connection portion 26. The spring arm portion 24 is linear and has a sheet-like structure, and forms an obtuse angle with each of the first connecting portion 25 and the second connecting portion 26. The elastic sheet 23 has simple structure and easy processing and manufacturing.

Preferably, as shown in fig. 8, the housing 22 and the elastic piece 23 form an integral structure. For example, the case 22 is formed by metal stamping, and the spring plate 23 is integrally stamped out by stamping at a position of the wall of the case 22 facing the vibrator component 28 in the vibration direction. The first connecting portion 25 is integrally connected to the housing 22. The second connecting portion 26 is welded to the vibrator assembly 28. In this way, the processing of the spring plate 23 and the connection of the spring plate 23 to the housing 22 are easier.

In addition, the space of the thickness of the elastic sheet 23 is saved, and the electromagnetic exciter can be made thinner.

Alternatively, as shown in fig. 7, the spring arm portion 24 may have a V-shaped configuration. The first connecting portion 25 and the second connecting portion 26 are formed by extending two free ends of the V-shaped structure outwards. The V-shaped structure has a larger expansion range, thereby increasing the amplitude of the vibrator assembly 28.

Alternatively, as shown in fig. 7, the elastic pieces 23 are plural and are respectively located at upper and lower sides of the vibrator assembly 28 in the vibration direction. For example, the elastic pieces 23 are two and are respectively located at the upper and lower sides of the vibrator assembly 28. In this way, the spring force experienced by the vibrator assembly 28 is more balanced.

It is also possible that, as shown in fig. 6, the plurality of spring pieces 23 are located on the same side of the vibrator assembly 28 in the vibration direction. For example, the number of the elastic pieces 23 is two. The vibrator assembly 28 has a rectangular parallelepiped structure. The two spring pieces 23 are juxtaposed on the same side of the vibrator assembly 28 in the same arrangement direction along the long axis of the vibrator assembly 28. In this way, the space of the cavity in the vibration direction can be saved, so that the electromagnetic exciter can be made thinner.

The number and the arrangement position of the elastic sheets can be set by a person skilled in the art according to actual needs.

In one example, the housing 22 has walls formed with bosses that project inwardly into the cavity. The first connecting portion 25 is fixed to the boss to form a gap between the arm portion 24 and the case wall. For example, the housing 22 is formed into a boss by stamping. The first connection 25 is welded to the boss. In this way, the space in which the spring plate 23 vibrates is increased. When the spring plate 23 is compressed, a gap is formed between the spring arm portion 24 and a portion of the housing 22 other than the boss, so that the spring plate 23 can be effectively prevented from striking the housing 22.

The height of the boss can be set by those skilled in the art according to actual needs.

According to another embodiment of the present invention, a screen sound emitting device is provided. The device comprises a screen body, a middle frame and the electromagnetic exciter provided by the invention. The middle frame can be a middle frame of a mobile phone, a smart watch, a tablet computer, a notebook computer, a game machine and the like. The screen body is installed on the center. The electromagnetic exciter is arranged on the screen body or the middle frame. The sound production device has the characteristics of good sound production effect and good heat dissipation effect.

In one example, the screen sounding device further comprises foam cotton. The electromagnetic exciter is fixedly connected with the screen body or the middle frame through foam cotton rubber.

The electromagnetic exciter can also be connected with the screen body or the middle frame through bolts. The connection mode can realize the firm connection of the electromagnetic exciter and the screen body or the middle frame.

Of course, other connection means may be used by those skilled in the art.

Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustrative purposes only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. An electromagnetic exciter comprising a housing, a vibrator assembly and a stator assembly, the stator assembly and the vibrator assembly being housed within the housing, the vibrator assembly being suspended within the housing by a resilient element, the vibrator assembly comprising a coil and a core disposed within the coil, the vibrator assembly being located in a magnetic field of the stator assembly, the stator assembly comprising a halbach array of permanent magnets;

the Halbach permanent magnet array comprises a first permanent magnet, a second permanent magnet and a third permanent magnet which are arranged in parallel along the vibration direction; the first permanent magnet and the third permanent magnet are oppositely magnetized, the magnetizing direction is parallel to the vibration direction, and the magnetizing direction of the second permanent magnet points to the coil.

2. An electromagnetic actuator according to claim 1, wherein the coil has a rectangular ring shape or a racetrack ring shape, and the first permanent magnet, the second permanent magnet, and the third permanent magnet are opposed to a long side of the coil.

3. The electromagnetic exciter of claim 1, further comprising a fourth permanent magnet and a fifth permanent magnet disposed at both ends of the second permanent magnet in the long axis direction, the fourth permanent magnet and the fifth permanent magnet being oppositely magnetized.

4. The electromagnetic actuator according to claim 1, wherein the core column includes a sixth permanent magnet and a seventh permanent magnet juxtaposed in the vibration direction, and the magnetization directions of the sixth permanent magnet and the seventh permanent magnet are opposite to each other.

5. The electromagnetic actuator according to claim 1, wherein said core column includes an eighth permanent magnet and a ninth permanent magnet juxtaposed perpendicularly to the vibration direction, said eighth permanent magnet and said ninth permanent magnet being oppositely magnetized.

6. The electromagnetic exciter of claim 1, wherein the resilient element comprises a spring plate, the spring plate comprising a first connection portion, a second connection portion, and a spring arm portion between the first connection portion and the second connection portion, the first connection portion being connected to the housing, the second connection portion being connected to the vibrator assembly.

7. An electromagnetic actuator according to claim 6, wherein the housing and the spring plate form a unitary structure.

8. The electromagnetic actuator according to claim 6 or 7, characterized in that the spring pieces are plural and respectively located on upper and lower sides of the vibrator assembly in a vibration direction; or the elastic sheets are positioned on the same side of the vibrator assembly along the vibration direction.

9. An electromagnetic actuator according to claim 6 or 7, wherein the spring arm portion is linear or V-shaped.

10. An electromagnetic actuator according to claim 6 or 7, wherein a boss protruding into a cavity is formed on a wall of the housing, and the first connecting portion is fixed to the boss to form a gap between the spring arm portion and the wall.

11. An electromagnetic actuator according to claim 1, wherein the housing is made of a magnetically permeable material.

12. A screen sound generating device comprising a screen body, a middle frame and an electromagnetic actuator as claimed in any one of claims 1 to 11, the electromagnetic actuator being provided on the screen body or the middle frame.

13. The screen sound generating device according to claim 12, further comprising foam adhesive, wherein the electromagnetic exciter is fixedly connected with the screen body or the middle frame through the foam adhesive; or,

the electromagnetic exciter is connected with the screen body or the middle frame through bolts.