Linear vibration motor

Abstract

The application provides a linear vibration motor, which comprises a shell with a containing space, a vibration assembly and a stator assembly contained in the containing space, the vibration assembly comprises a mass block with a containing space, a magnetic steel fixed to the mass block and an elastic piece for supporting the mass block in the containing space, the stator assembly comprises a coil fixed to the shell and arranged opposite to the magnetic steel and an iron core located in a hole of the coil, the iron core is formed by injection molding of liquid preform material made of an iron-based material and a polymer material and then solidification, the coil has a first matching surface surrounding the hole, the iron core comprises a second matching surface arranged opposite to the first matching surface and fixedly matched, and there is no gap between the second matching surface and the first matching surface. Compared with the related art, the linear vibration motor has good magnetic field performance and reliability.

Description

[Technical Field]

[0001] This invention relates to an electric motor, and more particularly to a linear vibration motor used in the field of mobile electronic products. [Background Technology]

[0002] With the development of electronic technology, portable consumer electronics products are becoming increasingly popular, such as mobile phones, handheld game consoles, navigation devices, and handheld multimedia entertainment devices. These electronic products generally use linear vibration motors for system feedback, such as call alerts, message alerts, navigation prompts, and vibration feedback in game consoles. Such widespread application requires vibration motors to have excellent performance and a long service life.

[0003] The linear vibration motor of the related technology includes a housing with a receiving space, a vibration component located in the receiving space, and a stator assembly fixed to the housing. The vibration component includes a mass block and a magnet, and the stator assembly includes a coil and an iron core. The magnetic field generated by the coil and the iron core interacts with the magnetic field generated by the magnet in the vibration component, thereby driving the vibration component to perform reciprocating linear motion to generate vibration.

[0004] However, in linear vibration motors of this technology, the iron core is generally a stamped part, which is assembled into the inner hole of the coil using a carrier after forming. Because a large gap is left between the inner holes of the coil for assembly to prevent scratching, this has an adverse effect on the magnetic properties. Furthermore, the gap can lead to significant errors in the position of the iron core; and fixing the iron core to the outer shell or flexible circuit board by gluing may not be strong enough, posing a risk of it falling off. Welding the iron core to the cover plate would increase the manufacturing cost.

[0005] Therefore, it is necessary to provide a new linear vibration motor to solve the above problems. [Summary of the Invention]

[0006] The purpose of this invention is to provide a linear vibration motor with high bonding strength between the iron core and the shell or flexible circuit board, low manufacturing difficulty, and good magnetic field performance.

[0007] To achieve the above objectives, the present invention provides a linear vibration motor, comprising a housing with a receiving space, a vibration assembly and a stator assembly housed within the receiving space. The vibration assembly includes a mass block with a receiving space, a magnet fixed to the mass block and housed within the receiving space, and an elastic member supporting the mass block within the receiving space. One end of the elastic member is fixed to the mass block, and the other end is fixed to the housing, thereby driving the mass block to vibrate along the vibration direction. The stator assembly includes a coil fixed to the housing and disposed opposite to the magnet, and a flexible circuit board electrically connecting the coil to an external circuit. The coil has an inner hole located in the middle. The stator assembly further includes an iron core housed within the inner hole. The coil has a first mating surface surrounding the inner hole. The iron core includes a second mating surface disposed opposite to and fixedly mated with the first mating surface, with no gap between the second mating surface and the first mating surface.

[0008] Preferably, the iron core is made of a viscous polymer material and a magnetically conductive iron-based material.

[0009] Preferably, the iron-based material is made into powder and then mixed with the polymer material to form a preform. The preform is injected into the inner hole by injection molding and then cured to form the iron core.

[0010] Preferably, the preform is formed into the iron core by UV curing or thermosetting.

[0011] Preferably, the polymeric material includes one or more of epoxy resin, polyester resin, or vinyl resin.

[0012] Preferably, the flexible circuit board is fixed to the housing, the coil is fixed to the side of the flexible circuit board facing the vibration assembly, and the iron core includes a third mating surface fixed to the flexible circuit board.

[0013] Preferably, the thickness direction of the coil is a first direction, and the height of the iron core along the first direction is equal to the thickness of the coil.

[0014] Preferably, the vibration direction of the linear vibration motor is perpendicular to the first direction.

[0015] Compared with related technologies, the core of the linear vibration motor of the present invention is made by mixing a magnetic iron-based material and a viscous polymer material into a liquid preform, which is then injected into the inner hole of the coil and cured. By preparing the core by curing the liquid material, the liquid material can be fully filled into the inner hole of the coil, so that there is no gap between the formed core and the coil, and the bonding strength with the shell or flexible circuit board is relatively high. The manufacturing process is simple, effectively reducing the risk of coil scratches, improving the utilization rate of the inner hole of the coil and the magnetic field strength, thereby making the linear vibration motor have good vibration performance and reliability. [Attached Image Description]

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0017] Figure 1 This is a three-dimensional structural diagram of the linear vibration motor of the present invention;

[0018] Figure 2 This is an exploded view of the linear vibration motor of the present invention;

[0019] Figure 3 For along Figure 1 Cross-sectional view of line AA;

[0020] Figure 4 This is a three-dimensional structural diagram of the linear vibration motor of the present invention;

[0021] Figure 5 For along Figure 4 Cross-sectional view of the middle BB line;

[0022] Figure 6 This is a three-dimensional structural diagram of the linear vibration motor of the present invention;

[0023] Figure 7 For along Figure 1 Cross-sectional view of the CC line;

[0024] Figure 8 This is a partial structural schematic diagram of the linear vibration motor of the present invention.

Detailed Implementation Methods

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Please also refer to Figure 1-8 The present invention provides a linear vibration motor 100, including a housing 20 having a housing space 10 and a vibration component 30 and a stator component 40 housed within the housing space 10.

[0027] The outer shell 20 includes an upper shell 22 having an opening 21 and a lower shell 23 fixed to the upper shell 22 and sealing the opening 21. The lower shell 23 and the upper shell 22 together enclose a receiving space 10.

[0028] The vibration assembly 30 includes a mass block 32 with a receiving space 31, a magnet 33 fixed to the mass block 32 and housed in the receiving space 31, and an elastic member 34 supporting the mass block 32 in the receiving space 10. One end of the elastic member 34 is fixed to the mass block 32 and the other end is fixed to the upper shell 22. The elastic member 34 drives the mass block 32 and the magnet 33 to reciprocate along the vibration direction, thereby providing a vibration sensation.

[0029] Specifically, the magnet 33 includes a first magnet 331 located in the middle and a second magnet 332 and a third magnet 333 respectively disposed on both sides of the first magnet 331 along the vibration direction; in this embodiment, the first magnet 331, the second magnet 332, and the third magnet 333 are preferably a Hellbeck array. The first magnet 331 is magnetized along the vibration direction, while the second magnet 332 and the third magnet 333 are magnetized perpendicular to the vibration direction and in opposite directions.

[0030] The stator assembly 40 includes a coil 41 fixed to the lower housing 23 and disposed opposite to the magnet 33, a flexible circuit board 42 electrically connecting the coil 41 to an external circuit, and an iron core 43; specifically, the coil 41 has an inner hole 44 located in the middle, and the iron core 43 is housed in the inner hole 44; it can be understood that the inner hole 44 is the winding hole formed by winding the coil 41.

[0031] The coil 41 has a first mating surface 45 that surrounds and forms an inner hole 44. The iron core 43 includes a second mating surface 46 that is opposite to and fixedly fitted with the first mating surface 45. There is no gap between the first mating surface 45 and the second mating surface 46. Compared with the prior art, the outer surface of the iron core 43, i.e., the second mating surface 46, and the inner surface of the coil 41, i.e., the first mating surface 45, are tightly fitted, which effectively increases the volume of the iron core 43, improves the utilization rate of the inner hole 44 of the coil 41, enhances the magnetic field performance of the linear vibration motor, and is beneficial to improving the vibration sensation.

[0032] Unlike existing technologies, the iron core 43 in this invention is made of an iron-based material with magnetic conductivity and a polymer material with a certain viscosity. Specifically, the iron-based material is made into powder and then mixed with the polymer material to form a liquid preform. The preform is then injected into the inner hole through injection molding and cured to form the iron core 43. Optionally, the preform can be cured by UV curing or thermosetting. This method of preparing the iron core 43 not only allows the liquid material to fully fill the inner hole 44 of the coil 41, improving the utilization rate of the inner hole 44 and thus enhancing the magnetic field performance, but also avoids scratching the coil 41, improving the yield. The iron core 43 has high bonding strength with the lower shell 23 or the flexible circuit board 42, and does not require welding or gluing, reducing process difficulty and cost while significantly improving the bonding strength between the iron core and the shell or flexible circuit board, thus enhancing the reliability of the linear vibration motor. It is understood that in this embodiment, the flexible circuit board 42 is disposed between the coil 41 and the lower shell 23, that is, the coil 41 is fixed to the side of the flexible circuit board 42 facing the vibration assembly 30, and the iron core 43 is fixed to the flexible circuit board 42. The iron core 43 includes a third mating surface 47 fixed to the flexible circuit board 42. In other embodiments, the iron core 43 can also be directly fixed to the lower shell 23, which can be designed according to actual needs. Since the liquid preform needs to be cured by UV light or heat, the polymer material is preferably a thermosetting resin such as epoxy resin, polyester resin or vinyl resin.

[0033] Even better, the thickness direction of coil 41 is defined as the first direction X, and the height of iron core 43 along the first direction X is equal to the thickness of coil 41. In this way, the inner hole 44 of coil 41 can be fully utilized, and the magnetic field performance is significantly improved.

[0034] Furthermore, the elastic element 34 comprises two elements, with one elastic element 34 connected to each end of the mass block 32 along the vibration direction. The interaction between the coil 41, the iron core 43, and the magnet 33 generates a driving force, causing the elastic element 34 to drive the mass block 32 and the magnet 33 to reciprocate along the vibration direction, providing a vibration sensation. It is understood that in this embodiment, the vibration direction is perpendicular to the first direction X.

[0035] Compared with related technologies, the core of the linear vibration motor of the present invention is made by mixing a magnetically conductive iron-based material and a viscous polymer material into a preform, which is then injected into the inner hole of the coil and cured. By preparing the core by curing liquid material, the liquid material can be fully filled into the inner hole of the coil, so that there is no gap between the formed core and the coil, the bonding strength with the shell or flexible circuit board is relatively high, the manufacturing process is less difficult, effectively reducing the risk of coil scratches, improving the utilization rate of the inner hole of the coil and the magnetic field strength, thereby making the linear vibration motor have good vibration performance and reliability.

[0036] The above description is merely an embodiment of the present invention. It should be noted that those skilled in the art can make improvements without departing from the inventive concept of the present invention, but these improvements all fall within the protection scope of the present invention.

Claims

1. A linear vibration motor, comprising a housing having a receiving space and a vibration assembly and a stator assembly housed within the receiving space, the vibration assembly comprising a mass block having a receiving space, a magnet fixed to the mass block and housed within the receiving space, and an elastic member supporting the mass block within the receiving space, one end of the elastic member being fixed to the mass block and the other end being fixed to the housing and driving the mass block to vibrate along a vibration direction, the stator assembly comprising a coil fixed to the housing and disposed opposite to the magnet, and a flexible circuit board electrically connecting the coil to an external circuit, characterized in that... The coil has an inner hole located in the middle, and the stator assembly further includes an iron core housed in the inner hole. The coil has a first mating surface that surrounds and forms the inner hole. The iron core includes a second mating surface that is opposite to and fixedly fitted with the first mating surface. There is no gap between the second mating surface and the first mating surface. The iron core is formed by injection molding a liquid preform of a mixture of a magnetic iron-based material and a viscous polymer material into the inner hole and then solidifying it.

2. The linear vibration motor according to claim 1, characterized in that, The preform material is formed into the iron core by UV curing or thermosetting.

3. The linear vibration motor according to claim 1, characterized in that, The polymeric material includes one or more of epoxy resin, polyester resin, or vinyl resin.

4. The linear vibration motor according to claim 1, characterized in that, The flexible circuit board is fixed to the outer shell, the coil is fixed to the side of the flexible circuit board facing the vibration assembly, and the iron core includes a third mating surface fixed to the flexible circuit board.

5. The linear vibration motor according to claim 1, characterized in that, The thickness direction of the coil is a first direction, and the height of the iron core along the first direction is equal to the thickness of the coil.

6. The linear vibration motor according to claim 5, characterized in that, The vibration direction of the linear vibration motor is perpendicular to the first direction.

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