JP2016198733A - Linear vibration motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize operation characteristics of a linear vibration motor by solving a deviation of a supporting position of a spring end portion.SOLUTION: A linear vibration motor 1 includes: a movable element 10 equipped with a magnet 2 and a weight 3; a frame body 4 which supports the movable element 10 so as to reciprocate and vibrate; a coil 5 which is fixed to the frame body 4, and adds driving force for vibrating the movable element 10 to the magnet 2; and a coil spring 6 which is provided between the frame body 4 and the movable element 10. On one or both of the movable element 10 and the frame body 4, a supporting portion 20 for supporting an end portion 6A of the soil spring 6 is provided. The supporting portion 20 is equipped with a tapered surface 21 inclined to a center axis 6P of the coil spring 6 at a fixed angle. The end portion 6A of the coil spring 6 abuts on the tapered surface 21 to be supported.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a linear vibration motor that reciprocally vibrates a mover by signal input.

  A vibration motor (or vibration actuator) is widely used as a device that is built in a portable electronic device and transmits a signal generation such as an incoming call or an alarm to a user by vibration. In recent years, vibration motors have attracted attention as devices for realizing haptics (skin sensation feedback) in human interfaces such as touch panels.

  As various types of vibration motors are being developed, linear vibration motors that can obtain relatively large vibrations by linearly reciprocating vibration of a mover are known. This linear vibration motor supports a mover equipped with a magnet and a weight so that it can reciprocate with a spring, and an alternating current having a frequency equal to the natural frequency of the spring and mover is passed through a fixed coil to the magnet. A driving force for reciprocating vibration is applied (see Patent Document 1 below).

JP 2012-016153 A

  In the conventional linear vibration motor, a spring is arranged between the mover and the frame to elastically support the mover, and the end of the spring is placed on a convex or concave spring receiving portion provided on the frame or the mover. The support position of the spring is positioned by engaging the part (end turn part). At this time, there is a problem in that the position of the spring end portion with respect to the spring receiving portion is deviated within the range of the tolerance of the inner and outer diameters of the spring end portion and the tolerance of the uneven diameter of the spring receiving portion.

  Since such a deviation occurs in the radial direction of the spring end, the direction of the elastic force of the spring is inclined with respect to the vibration direction of the mover, or the position of the spring end is moved during the vibration of the mover. Changing the direction of the elastic force of the spring may adversely affect the operating characteristics of the linear vibration motor.

  This invention makes it an example of a subject to cope with such a problem. That is, an object of the present invention is to eliminate the shift of the support position of the spring end portion and to stabilize the operation characteristics of the linear vibration motor.

In order to achieve such an object, the linear vibration motor of the present invention has the following configuration.
A mover including a magnet and a weight, a frame that supports the mover in a freely reciprocating manner, a coil that is fixed to the frame and that applies a driving force to the magnet to vibrate the mover, and the frame And a coil spring provided between the movable element and the movable element, and one or both of the movable element and the frame body are provided with a support part that supports an end of the coil spring, and the support part includes the coil spring. A linear vibration motor comprising a tapered surface inclined at a constant angle with respect to a central axis of the coil spring, wherein an end portion of the coil spring is supported in contact with the tapered surface.

  The linear vibration motor of the present invention having such a feature can support the end portion of the coil spring that reciprocally vibrates the mover without displacement, and can stabilize the operation characteristics of the linear vibration motor.

It is a disassembled perspective view of the linear vibration motor which concerns on embodiment of this invention. It is explanatory drawing ((a) is a front view, (b) is AA sectional drawing) of the linear vibration motor which concerns on embodiment of this invention. It is explanatory drawing which showed the support part of the linear vibration motor which concerns on embodiment of this invention ((a) is a support part convex with respect to a coil spring, (b) is a support part concave with respect to a coil spring). It is explanatory drawing which showed the support part of the linear vibration motor which concerns on other embodiment of this invention. It is explanatory drawing ((a) is a front view, (b) is AA sectional drawing) of the linear vibration motor which concerns on other embodiment of this invention. It is explanatory drawing which showed the portable electronic device (mobile information terminal) equipped with the linear vibration motor which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, common parts in the drawings are denoted by the same reference numerals, and redundant description for each figure is omitted.

  A linear vibration motor 1 according to an embodiment of the present invention includes a mover 10 including a magnet 2 and a weight 3, a frame 4 that supports the mover 10 so as to freely reciprocate, and a coil 5 that is fixed to the frame 4. The coil spring 6 disposed between the mover 10 and the frame 4 is provided. In the figure, the X direction indicates the vibration direction, the Y direction indicates the width direction intersecting the vibration direction, and the Z direction indicates the height (thickness) direction.

  The linear vibration motor 1 (1A) shown in FIGS. 1 and 2 includes three magnets 2A, 2B, and 2C that are arranged along the vibration direction as the magnet 2. Spacer yokes 7 are disposed between the magnets 2A, 2B, and 2C, respectively. The magnets 2A, 2B, and 2C are magnetized along the vibration direction (the X direction in the drawing), and are arranged so that the magnetic poles facing each other are the same. That is, along the X direction, if one magnetic pole of the magnet 2A is an N pole and the other magnetic pole is an S pole, the magnetic pole of the magnet 2B arranged next to the magnet via the spacer yoke 7 is on the magnet 2A side. The magnetic pole is the S pole, and the magnetic pole on the opposite side is the N pole. The magnetic pole of the magnet 2 </ b> C arranged next to it via the spacer yoke 7 is the magnetic pole on the magnet 2 </ b> B side and the magnetic pole on the opposite side. Is the S pole.

  The coil 5 to which the drive current is applied is disposed with a gap around the spacer yoke 7 and is fixed to the frame body 4. The coil 5 is wound so that the magnetic flux directed from the spacer yoke 7 toward the magnetic body (frame body 4) disposed around the coil yoke or the magnetic flux directed from the surrounding magnetic body (frame body 4) toward the spacer yoke 7 is traversed. ing. As a result, a driving force (Lorentz force) along the X-axis direction is applied to the magnet 2 (2A, 2B, 2C) including the spacer yoke 7. The magnets 2 (2A, 2B, 2C) including the spacer yoke 7 are integrally connected and reinforced by a reinforcing member 8 extending along the X-axis direction.

  A pair of weights 3 are attached to both ends in the X direction of the magnet 2 that is integrally connected and reinforced. Thereby, the needle | mover 10 provided with the magnet 2 and the weight 3 is formed. In the example shown in FIGS. 1 and 2, a guide shaft 11 extending along the X direction from both ends of the weight 3 is fixed to the weight 3.

  The frame body 4 includes a bearing 12 that slidably supports the guide shaft 11, thereby supporting the movable element 10 to which the guide shaft 11 is fixed so as to be capable of reciprocating vibration along the X direction. In the illustrated example, the frame body 4 has a front surface portion 4D and 4E formed of a pair of plate pieces fixed to a refracted plate body having a bottom surface portion 4A and side wall portions 4B and 4C, and further a flat plate upper lid portion 4F. And has a box shape that is long in the vibration direction (X direction) and thin in the thickness direction (Z direction).

  The coil springs 6 are provided between the mover 10 and the frame body 4 so as to be freely elastically deformable along the X direction. In this example, a total of four coil springs 6 are arranged, two on each side of the X direction. ing. The four coil springs 6 are arranged at symmetrical positions with respect to the axis along which the guide shaft 11 extends.

  Both the mover 10 and the frame 4 are provided with a support portion 20 that supports the end portion 6 </ b> A of the coil spring 6. In the illustrated example, the support portion 20 is provided on both the mover 10 and the frame body 4. However, the support portion 20 is provided on only one of the mover 10 and the frame body 4, and one end portion 6 </ b> A of the coil spring 6 is provided. The other end 6A of the coil spring 6 may be fixed to the other of the mover 10 and the frame 4 by welding or the like. In the illustrated example, the support portion 20 is provided at the front portions 4D and 4E of the frame body 4 and the end portion of the weight 3 in the mover 10.

  FIG. 3A shows a specific configuration of the support portion 20. The support portion 20 includes a tapered surface 21 with which the end portion 6A of the coil spring 6 abuts. In the example shown in FIG. 3A, the support portion 20 includes a convex portion that enters the end portion 6 </ b> A of the coil spring 6, and a tapered surface 21 that contacts the inside of the end portion 6 </ b> A is provided on the outer surface of the convex portion. It has been.

  The tapered surface 21 is inclined at a constant angle (taper angle θ) with respect to the central axis 6P of the coil spring 6. The tapered surface 21 is provided all around the central axis 6P, or partially so that the end 6A of the coil spring 6 can be positioned, and has a constant taper angle θ with respect to the central axis 6P on all surfaces. ing.

  When such a taper surface 21 is provided on the support portion 20 and the inside of the end portion 6A of the coil spring 6 is brought into contact with the taper surface 21, the dimension of the inner diameter W1 of the end portion 6A of the coil spring 6 is somewhat deviated from a set value. Even when the taper is detached, if the degree of detachment is within the range between the minimum diameter T1 and the maximum diameter T2 of the tapered surface 21, the position of contact with the tapered surface 21 is changed, and the end 6A is supported by the tapered surface 21 without deviation. can do. The difference between the maximum diameter T2 and the minimum diameter T1 of the tapered surface 21 is appropriately set in consideration of the tolerance of the inner diameter W1 of the end 6A of the coil spring 6 and the dimensional tolerance of the tapered surface 21.

  FIG. 3B shows another example of the support unit 20. In this example, the support portion 20 includes a concave portion that accommodates the end portion 6 </ b> A of the coil spring 6, and a tapered surface 21 that contacts the outer side of the end portion 6 </ b> A of the coil spring 6 is provided on the inner side surface of the concave portion. In this example as well, the tapered surface 21 is inclined at a certain angle (taper angle θ) with respect to the central axis 6P of the coil spring 6 in the same manner as the example described above.

  Also in this example, by providing the support portion 20 with the tapered surface 21 and bringing the outside of the end portion 6A of the coil spring 6 into contact with the tapered surface 21, the size of the outer diameter W2 of the end portion 6A of the coil spring 6 is somewhat. Even when deviating from the set value, if the degree of detachment is within the range of the minimum diameter T1 and the maximum diameter T2 of the tapered surface 21, the position of contact with the tapered surface 21 is changed, and the end 6A is changed by the tapered surface 21. It can be supported without deviation.

  The linear vibration motor 1 (1A) shown in FIGS. 1 and 2 reciprocates to and from the magnet 2 including the spacer yoke 7 by passing an alternating current having a frequency equal to the natural frequency of the coil spring 6 and the mover 10 to the coil 5. A driving force for vibration is applied, and the mover 10 reciprocally vibrates along the X direction. At that time, since the end portion 6A of the coil spring 6 is supported by the support portion 20 without being displaced, the direction of the elastic force by the coil spring 6 becomes constant, and stable operating characteristics can be exhibited.

  In particular, by making the central axis of the support portion 20 coincide with the axial direction of the guide shaft 11, the direction of the elastic force of all the coil springs 6 is parallel to the axial direction of the guide shaft 11, and along the axial direction of the guide shaft 11. Stable reciprocating vibration can be realized. At that time, the coil spring 6 is elastically deformed along the central axis 6P, and the problem that the coil spring 6 is buckled and contacts the frame 4 can be avoided. Moreover, since the elastic force of the coil spring 6 can be made to act symmetrically with respect to the guide shaft 11, the problem that the mover 10 rotates around the axis of the guide shaft 11 during reciprocating vibration can be solved.

  The linear vibration motor 1 (1B) shown in FIGS. 4 and 5 is different from the form shown in FIGS. 1 and 2, and the movable element 10 reciprocates to the frame body 4 via a rolling element (bearing) 13. It is supported freely. A plurality of (three in the illustrated example) rolling elements 13 are arranged on one side of the weight 3 of the mover 10. A groove 3P is formed on one surface of the weight 3 along the vibration direction (X direction), and the rolling elements 13 are held in the groove 3P. Further, the upper cover portion 4F of the frame body 4 is formed with a groove portion 4F1 at a position facing the groove 3P, and the rolling element 13 is held between the groove 3P and the groove portion 4F1.

  The mover 10 has a movable frame 14 on which two weights 3 and two magnets 2D and 2E are fixed. The two magnets 2D and 2E are arranged side by side in the X direction, and are magnetized in opposite directions along the Z direction. A coil 5 having a pair of linear portions extending in the Y direction with respect to the two magnets 2D and 2E is fixed to the upper lid portion 4F, and passes from one of the two magnets 2D and 2E through the upper lid portion 4F which is a magnetic body. The coil 5 fixed to the upper lid portion 4F is disposed so as to cross the magnetic flux reaching the other of the two magnets 2D and 2E.

  In such a linear vibration motor 1 (1B), the support portion 20 described above is provided on the end portion of the movable frame 14 and the front portions 4D and 4E of the frame body 4, and the end portion of the coil spring 6 is provided on the support portion 20. Part 6A is supported. Also in the linear vibration motor 1 (1B), a driving force for reciprocal vibration is applied to the magnet 2 (2D, 2E) by applying an alternating current having a frequency equal to the natural frequency of the coil spring 6 and the mover 10 to the coil 5. Is applied, and the mover 10 reciprocally vibrates along the groove 3P or the groove portion 4F1. At that time, since the end portion 6A of the coil spring 6 is supported by the support portion 20 without shifting, the direction of the elastic force by the coil spring 6 becomes constant, and stable operating characteristics can be obtained.

  The form of the linear vibration motor 1 according to the embodiment of the present invention is not limited to the above-described example, and the movable element 10 including the magnet 2 and the weight 3 and the frame body that supports the movable element 10 so as to freely reciprocate. 4, a coil 5 fixed to the frame 4, and provided between the frame 4 and the mover 10, and provided with a coil 5 for applying a driving force for vibrating the mover 10 to the magnet 2, and elastically deformed by the vibration of the mover 10. If it is a form provided with the coil spring 6 to perform, it can become embodiment of this invention provided with the support part 20. FIG.

  The linear vibration motor 1 according to the embodiment of the present invention can be made thin and stable reciprocating vibration by using the frame 4 having a flat box shape. In particular, even when the frame body 4 is made as thin as the thickness of the mover 10, it is possible to avoid the coil spring 6 and the frame body 4 from contacting each other as much as possible, and the linear vibration motor that is thin but generates less noise. 1 can be obtained.

  FIG. 6 shows a portable information terminal 100 as an example of an electronic apparatus equipped with the linear vibration motor 1 according to the embodiment of the present invention. The portable information terminal 100 provided with the linear vibration motor 1 that can obtain stable vibration and can be thinned and compact in the width direction is unlikely to generate abnormal noise at the start and end of an incoming call or alarm function in a communication function. Can convey to the user with stable vibration Further, the portable information terminal 100 pursuing high portability or design can be obtained by making the linear vibration motor 1 thin and compact in the width direction. Furthermore, since the linear vibration motor 1 has a compact shape in which each part is housed in a rectangular parallelepiped frame 4 with a reduced thickness, the linear vibration motor 1 can be efficiently installed in the thinned portable information terminal 100. .

  As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to these embodiments, and the design can be changed without departing from the scope of the present invention. Is included in the present invention. In addition, the above-described embodiments can be combined by utilizing each other's technology as long as there is no particular contradiction or problem in the purpose and configuration.

1 (1A, 1B): linear vibration motor,
2 (2A, 2B, 2C, 2D, 2E): magnet,
3: weight, 3P: groove,
4: Frame body, 4A: Bottom portion, 4B, 4C: Side wall portion, 4D, 4E: Front portion,
4F: upper lid part, 4F1: groove part,
5: coil, 6: coil spring, 6A: end, 6P: central axis,
7: Spacer yoke, 8: Reinforcing member,
10: mover, 11: guide shaft, 12: bearing,
13: rolling element (bearing), 14: movable frame,
20: support part, 21: taper surface, θ: taper angle,

Claims (6)

A mover comprising a magnet and a weight;
A frame that supports the mover in a freely reciprocating manner;
A coil that is fixed to the frame and applies a driving force to the magnet to vibrate the mover;
A coil spring provided between the frame and the mover;
One or both of the mover and the frame is provided with a support portion that supports an end of the coil spring,
The linear vibration motor, wherein the support portion includes a tapered surface inclined at a constant angle with respect to a central axis of the coil spring, and an end portion of the coil spring is supported in contact with the tapered surface.   2. The linear vibration motor according to claim 1, wherein the support portion includes a convex portion that enters the end portion of the coil spring, and the tapered surface that is in contact with the inner side of the end portion is provided on an outer surface of the convex portion. .   2. The linear vibration motor according to claim 1, wherein the support portion includes a concave portion that accommodates an end portion of the coil spring, and the tapered surface that is in contact with the outer side of the end portion is provided on an inner surface of the concave portion.   4. The linear vibration motor according to claim 1, further comprising a guide shaft supported by the frame body, wherein the movable element reciprocally vibrates in one axial direction along the guide shaft. .   The linear vibration motor according to claim 1, wherein the movable element is slidably supported or rolled with respect to the frame body.   A portable electronic device provided with the linear vibration motor of any one of Claims 1-5.

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