JP2019106837A - Linear vibration motor - Google Patents

Abstract

To suppress oscillation of a movable element to a direction crossing an oscillation direction.SOLUTION: A linear vibration motor comprises: a stator 10; and a movable element 20 opposite to the stator 10 while having a prescribed clearance c, and oscillates the movable element 20 along the stator 10 by a magnetic force between a coil 12 provided at one of the stator 10 and the movable element 20 and a magnet 22 provided at the other side. The linear vibration motor further comprises: an elastic body 30 supporting the movable element 20, and the elastic body 30 is provided so as to be included to a direction separated from the stator when the movable element 20 is moved from an initial position, and be elastically deformed.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a linear vibration motor and an electronic device provided with the linear vibration motor.

  A vibration motor (or vibration actuator) is incorporated in a portable electronic device, widely used as a device for transmitting a signal such as an incoming call or an alarm to a portable person by vibration, and it is used in wearable electronic devices worn and carried by a portable person. Has become an essential device. The vibration motor is a device that realizes haptics (skin sensory feedback) in a human interface such as a touch panel.

While various forms of such vibration motors have been developed, a linear vibration motor that can generate relatively large vibrations due to linear reciprocating vibration of the mover has attracted attention.
For example, as described in Patent Document 1, a conventional linear vibration motor includes a mover integrally including a weight and two magnets, a leaf spring that vibratably supports the mover, and a mover. The coil has a coil facing the magnet on one side in a direction intersecting with the vibration direction, and the mover is reciprocally vibrated by the Lorentz force when the coil is energized. The two magnets are formed in a flat rectangular parallelepiped shape, and the flat surface side of one of the magnets is an N pole, whereas the flat surface side of the other magnet is an S pole.

JP, 2017-18958, A

  By the way, in the above-mentioned conventional linear vibration motor, when the magnet is displaced with respect to the coil due to the movement of the mover accompanying the vibration, the magnetic force line direction of the magnet orthogonal to the current direction changes with respect to the current direction of the coil. A Lorentz force in the cross direction to the vibration direction is generated, and the mover may swing in the cross direction due to the Lorentz force, which may lower the noise reduction and the durability.

In order to solve such a subject, the present invention comprises the following composition.
A stator and a mover opposed to each other with a predetermined clearance in the stator, and between the coil provided to one of the stator and the mover and a magnet provided to the other A linear vibration motor configured to vibrate the mover along the stator by magnetic force, comprising an elastic body for supporting the mover, wherein the elastic body moves the mover from an initial position. A linear vibration motor characterized in that it is elastically deformed while being inclined in a direction away from the stator.

It is an exploded perspective view showing an example of a linear vibration motor concerning the present invention. It is a top view which shows the state which removed the cover member and yoke about the linear vibration motor. It is sectional drawing which cut | disconnected the linear vibration motor in the center part of the transversal direction. It is a schematic diagram explaining the effect | action of the linear vibration motor, (a) shows an initial position, (b) shows the state which the mover biased to one side with vibration. It is a perspective view which shows an example of an electronic device.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same reference numerals in different drawings denote portions having the same functions, and redundant description in each drawing will be appropriately omitted.

  The linear vibration motor 1 comprises, as shown in FIGS. 1 to 4, a stator 10, a mover 20 facing the stator 10 with a predetermined clearance c therebetween, and an elastic body 30 supporting the mover 20. The mover is reciprocated linearly in one axial direction by magnetic force between the coil 12 on the stator side and the magnet 22 on the mover side.

  The stator 10 integrally includes a flat base 11, a coil 12 fixed on the base 11, and a cover portion 13 fixed on the base 11 so as to cover the coil 12 and the mover 20 and the like. Equipped with

  The base 11 is formed of a nonmagnetic hard material so that the attraction of the magnet 22 described later does not act, and according to the illustrated example, has a rectangular flat plate shape.

The coil 12 is obtained by winding a coated electric wire in a flat air-core shape along the coil facing surface of the magnet 22, and fixes one end face in the thickness direction to the surface of the base 11. In other words, the coil 12 is obtained by winding the electric wire in a flat air core shape along the vibration direction.
The coil 12 includes a half portion 12a facing one of the magnetic poles (N pole) in the coil facing surface of the magnet 22 and another half 12b facing the other magnetic pole (S pole) in the coil facing surface. They are arranged at substantially line symmetry at intervals.

  In one half 12a and the other half 12b, the current directions intersecting the vibration direction are opposite. That is, in FIG. 3, when the current direction of one half 12a goes from the front to the back, the current direction of the other half 12b goes from the back to the front.

  The cover portion 13 is formed in a box shape with a magnetic hard material open at the lower side, and has a rectangular top wall 13a, and side walls 13b and 13c projecting downward from both side ends of the top wall 13a. It has a front wall portion 13d and a rear wall portion 13e which project downward from the front and rear end portions of the top wall portion 13a. The cover 13 is fixed to the circumferential end of the base 11.

  In addition, the mover 20 includes a weight 21, a magnet 22 fixed on the center side of the weight 21, and a yoke 23 fixed on the non-coil side of the magnet 22 (in other words, the opposite side to the coil side). It is equipped with one.

  The weight 21 is made of a metal material (for example, tungsten) having a high specific gravity, and according to the illustrated example, is formed in a substantially rectangular shape elongated in the vibration direction. A plurality of (two according to the illustrated example) hollow portions 21a having openings in one side and the other side in the thickness direction are provided on the center side in plan view of the weight 11 at intervals in the vibration direction.

The magnet 22 only needs to have one magnetic pole on one side in the vibration direction of the coil facing surface and an opposite magnetic pole on the other side, and as a specific example, as shown in FIG. And, it is composed of two magnet pieces 22a and 22b of the same material and opposite in magnetic pole.
One magnet piece 22a is fitted to one hollow portion 21a of the weight 21 with the N pole facing the one half portion 12a of the coil 12, and the other magnet piece 22b is the other half of the coil 12 of the S pole. The other hollow portion 21 a of the weight 21 is fitted to face the portion 12 b.

  The yoke 23 is a flat magnetic material, and is adhered and fixed to the surface of the two magnet pieces 22a and 22b on the side opposite to the coil, to increase the magnetic force of the magnets 22a and 22b.

The elastic body 30 is provided on one end side and the other end side of the movable element 20 in the vibration direction.
Each elastic body 30 is inclined in a direction away from the stator 10 (coil 12) with respect to the direction (X direction in the figure) of the initial Lorentz force L1 when the mover 20 moves away from the initial position with vibration. One end side is fixed to the mover 20 in a posture along the direction of the inclination (a posture inclined by an angle α according to an example in FIG. 3 and FIG. 4) so as to elastically deform, and the other end side It is fixed to a stationary part on the stator 10 side (see FIG. 3).

  More specifically, each elastic body 30 is a plate spring that covers one end side in the vibration direction of the mover 20 in a U-shape, and is a main body piece extended along one end face in the vibration direction of the mover 20 There is a portion 31, a movable side fastening piece 32 extending from one end side of the main body piece 31, and a stationary side fastening piece 33 extending from the other side of the main body piece 31. The movable side fastening piece 32 is fastened to one side of the mover 20 in a posture inclined at an angle α, and the fixed side fastening piece 33 is fastened to the side wall 13 b (or 13 c) of the cover 13. I'm wearing it.

Next, the characteristic operation and effect of the linear vibration motor 1 having the above-described configuration will be described in detail.
FIGS. 4A and 4B schematically show the operation when the linear vibration motor 1 moves in one direction along the vibration direction.
First, in an initial state in which the coil 12 is not energized, the mover 20 is substantially equally biased by the elastic bodies 30 on both sides, and is positioned approximately at the center of the coil 12.

In the initial state, when AC power is supplied to the coil 12, the mover 20 reciprocates by the magnetic action between the coil 12 and the magnet 22.
More specifically, as shown in FIG. 4A, when a current in one direction flows through the coil 12, the magnet is directed to the direction of the current in one half 12a and the other half 12b of the coil 12, respectively. Since the magnetic lines of force M1 in the coil thickness direction of the pieces 22a and 22b are substantially orthogonal to each other, the mover 20 generates a Lorentz force L1 in a direction (X direction according to the illustrated example) substantially parallel to the end face of the coil 12. Therefore, the mover 20 starts to move in the direction of the Lorentz force L1.
Similarly, the magnetic flux M2 in the direction along the coil end face between the two magnet pieces 22a and 22b is substantially orthogonal to the direction of the current in the one half 12a and the other half 12b of the coil 12. The Lorentz force L2 in a direction crossing the end face of the coil 12 and approaching the coil 12 (opposite direction to the Z direction according to the illustrated example) and the Lorentz force L3 in a direction crossing the end face of the coil 12 and away from the coil 12 Occur.

  As shown in FIG. 4B, when the mover 20 is separated from the initial position forward (in the X direction), the portion between the two magnet pieces 22a and 22b faces the other half 12b of the coil 12. Do. Therefore, the magnetic lines of force M2 in the direction along the coil end face between the two magnet pieces 22a and 22b are substantially orthogonal to the direction of the current in the other half 12b of the coil 12, and the mover 20 has the coil 12 end face A Lorentz force L2 is generated in a direction crossing the coil 12 (opposite to the Z direction according to the illustrated example).

In addition, when the mover 20 moves forward (in the X direction), the elastic body 30 on the front side tends to contract forward and obliquely upward, so that the mover 20 moving forward moves away from the stator 10 A tilting force E (see FIG. 4) also acts.
More specifically, when the mover 20 moves forward, as shown in FIG. 2, the angle between the main body piece 31 and the movable side fastening piece 32 widens while the angle between the main body piece 31 and the fixed side increases. As the angle between the fastening pieces 33 narrows, the body piece 31 pivots with the connecting portion 30b as a supporting shaft. At this time, since the entire elastic body 30 including the support shaft is inclined at the angle α, the connection portion 30 a side is going to be separated from the stator 10 while rotating. Therefore, a force E (see FIG. 4) inclined to the Z direction acts on the mover 20, and the force E and the Lorentz force L2 are offset.

  When the mover 20 moves forward (rightward according to FIG. 4), the elastic angle of the front elastic body 30 slightly increases due to elastic deformation in the Z-axis direction. Further, the elastic body 30 on the rear side (left side according to FIG. 4) has a small inclination angle α due to elastic deformation in the Z-axis direction. For this reason, the mover 20 moves substantially parallel to the end face of the coil 12.

  Therefore, according to the linear vibration motor 1 having the above configuration, the mover 10 is prevented from swinging in the direction intersecting with the vibration direction by the offset of the Lorentz force L2 and the force E, and the mover 10 is smoothly straightened. In this way, the movement of the movable element 10 can be stabilized and the noise can be reduced.

Next, an electronic device provided with the linear vibration motor 1 will be described.
FIG. 5 exemplifies a portable information terminal 100 as an electronic device provided with the linear vibration motor 1 according to the embodiment of the present invention.
The portable information terminal 100 is configured to vibrate the linear vibration motor 1 according to the reception of an external signal, the touch operation of a touch operation panel (including a touch display), etc., and the noise when the linear vibration motor 1 vibrates. And noise can be effectively reduced.

  In addition, as another example of the electronic device on which the linear vibration motor 1 is mounted, a wearable computer, a tablet personal computer, a game machine, or the like may be used other than the illustrated example.

Further, according to the above embodiment, the elastic body 30 is a U-shaped leaf spring as a particularly preferable example, but as another example of the elastic body 30, one end side is an end face of the elastic body 30 in the vibration direction. It is also possible to use a leaf spring having a configuration other than the example shown in the drawings, such as a leaf spring which is fixed and fixed to the fixed portion on the stator 10 side and elastically bent at the other end.
Furthermore, as another example of the elastic body 30, it is also possible to adopt an embodiment using an elastic material such as a coil spring or rubber.

  Moreover, according to the said embodiment, although the magnet 22 was comprised from two magnet piece 22a, 22b, as another example, it is also possible to set it as the aspect which comprised the magnet 22 from one or three or more magnet pieces. is there.

  Further, according to the above embodiment, the coil 12 is provided on the stator 10 side and the magnet 22 is provided on the mover 20 side, but as another example, a magnet is provided on the stator side and the coil is provided on the mover side Can be provided.

  As mentioned above, although the embodiment of the present invention has been described in detail, the specific configuration is not limited to these embodiments, and even if there is a design change or the like within the scope of the present invention. Included in the invention. In addition, the respective embodiments described above can be combined with each other by utilizing the techniques of each other unless there is a contradiction or a problem in particular in the purpose, the configuration, and the like.

1: linear vibration motor 10: stator 11: base 12: coil 13: cover 20: mover 21: weight 22: magnet 22a, 22b: magnet piece 23: yoke 30: elastic body 31: body piece 32: Movable side fastening piece 33: Fixed side fastening piece c: Clearance 100: Mobile information terminal (electronic equipment)

Claims (6)

  A stator and a mover opposed to each other with a predetermined clearance in the stator, and between the coil provided to one of the stator and the mover and a magnet provided to the other A linear vibration motor configured to vibrate the mover along the stator by magnetic force, comprising an elastic body for supporting the mover, wherein the elastic body moves the mover from an initial position. A linear vibration motor characterized in that it is elastically deformed while being inclined in a direction away from the stator.   The elastic body is fixed to the mover at one end side thereof at a posture along the direction of the inclination, and fixed to the stationary portion at the other side of the stator side at the other end side. The linear vibration motor according to Item 1.   The elastic body includes a main body piece provided along one end face in the vibration direction of the mover, a movable side fastening piece extending from one end of the main body piece, and the main body piece. A leaf spring having a fixed side attachment piece portion extended from the other end side, and fixing the movable side attachment piece portion to the mover in a posture along the direction of the inclination; The linear vibration motor according to claim 1, wherein the fixed side fixing piece portion is fixed to the stationary portion on the stator side. The magnet has one magnetic pole on one side of the coil facing surface in the vibration direction and the other magnetic pole on the other side.
The coil has one half facing the one magnetic pole and the other half facing the oppositely facing magnetic pole, and the one half and the other half cross in the vibration direction. The linear vibration motor according to any one of claims 1 to 3, wherein is reversed.   The linear vibration motor according to any one of claims 1 to 4, wherein the coil is provided on the stator, and the magnet is provided on the mover so as to face one end surface of the coil. The electronic device provided with the linear vibration motor in any one of Claims 1-5.

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