JP2016208608A - Linear vibration motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear vibration motor which inhibits a movable element from rotating around a vibration axis and causing abnormal noise even when the movable element is formed into a flat shape.SOLUTION: A linear vibration motor 1 includes: a movable element 10 including a magnetic pole part 2 and a weight part 3; a frame body 4 which supports the movable element 10 so that the movable element 10 may vibrate in a reciprocating manner; a coil 5 which is fixed to the frame body 4 and applies a driving force to the magnetic pole part 2; a guide shaft 6 which restricts vibration of the movable element 10 in a uniaxial direction; and an elastic member 8 which is elastically deformed by reciprocating vibration of the movable element 10. The movable element 10 has a flat shape and is provided with a contact part 20, in which the movable element 10 and the frame body 4 partially contact with each other, at a position separated from the guide shaft 6 in a width direction of the movable element 10. In the contact part 20, the movable element 10 is biased to the frame body 4 side by a magnetic force of the magnetic pole part 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a linear vibration motor that generates reciprocal vibration in response to an input signal.

  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 have been developed, a linear vibration motor that can generate a relatively large vibration by linear reciprocating vibration of a mover is known. A conventional linear vibration motor is provided with a weight and a magnet on the mover side, and a Lorentz force acting on the magnet by energizing a coil provided on the stator side serves as a driving force, which is elastically supported along the vibration direction. The child is reciprocally vibrated (see Patent Document 1 below).

JP 2011-97747 A

  With the reduction in size and thickness of portable electronic devices, there is a demand for further reduction in size and thickness of vibration motors installed therein. In particular, in an electronic device equipped with a flat panel display unit such as a smartphone, the space in the device in the thickness direction orthogonal to the display surface is limited. is there.

  When thinning the linear vibration motor, if the magnet volume is sufficiently secured to obtain a desired driving force and the weight of the weight is sufficiently secured to obtain a desired inertial force, the magnet and the weight are The mover provided is made flat, and the thickness is reduced while securing the volume of the magnet and the weight of the weight. In this case, if the mover rotates around the linear vibration axis, the flat shaped mover is shaped so that the side part easily collides with the surrounding frame body due to the rotation. If this occurs, stable operation cannot be obtained. For this reason, the prior art provides two guide shafts to suppress rotation of the movable element around the vibration axis, and realizes stable linear vibration. However, when two guide shafts are provided, it is necessary to ensure the parallelism of the two guide shafts, and high accuracy is required for assembly, and thus there is a problem that it is difficult to improve productivity.

  This invention makes it an example of a subject to cope with such a problem. In other words, it is possible to reduce the thickness of the linear vibration motor, and even when the mover is made flat, it prevents the mover from rotating around the vibration axis and generating abnormal noise. It is an object of the present invention to obtain a stable vibration without using a material and to obtain a high productivity.

In order to achieve such an object, the linear vibration motor of the present invention has the following configuration.
A mover including a magnetic pole part and a weight part, a frame body that supports the mover in a freely reciprocating manner, a coil that is fixed to the frame body and applies a driving force to the magnetic pole part, and a vibration of the mover A guide shaft that regulates in a single axial direction, and an elastic member that is provided between the frame and the movable element and elastically deforms by reciprocating vibration of the movable element, and the movable element is an axis of the guide shaft. The width in the direction intersecting the direction is a rectangular shape that is equal to or greater than the thickness in the direction intersecting the axial direction of the guide shaft, and at a position away from the guide shaft in the width direction of the mover, A linear vibration motor characterized in that a contact portion where the mover and the frame body are in partial contact is provided, and at the contact portion, the mover is biased toward the frame body by the magnetic force of the magnetic pole portion.

  In the linear vibration motor of the present invention having such characteristics, the mover vibrates along the guide shaft. At this time, the mover is urged by the magnetic force to the frame body side and always contacts the frame body side at the contact portion. Vibrates in a state. Accordingly, the mover can be prevented from rotating around the vibration axis, and stable vibration along the guide shaft and the contact portion can be obtained.

  Such a linear vibration motor 1 can suppress the occurrence of abnormal noise due to the mover colliding with the frame even when the mover is rectangular, and there is no need to use two guide shafts. Therefore, stable vibration can be obtained without using highly accurate parts. In addition, since high-precision assembly is not required, high productivity can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing ((a) is a top view, (b) is AA sectional drawing) which shows the whole structure of the linear vibration motor which concerns on 1st Embodiment of this invention. It is explanatory drawing (plan view of the state except a cover frame) which shows the internal structure of the linear vibration motor (example which provided one rolling element) which concerns on 1st Embodiment of this invention. It is explanatory drawing (plan view of the state except a cover frame) which shows the internal structure of the linear vibration motor (example which provided the some rolling element) which concerns on 1st Embodiment of this invention. It is explanatory drawing ((a) is a top view, (b) is AA sectional drawing) which shows the whole structure of the linear vibration motor which concerns on 2nd Embodiment of this invention. It is explanatory drawing (plan view of the state except a cover frame) which shows the internal structure of the linear vibration motor which concerns on 2nd Embodiment of this invention. It is explanatory drawing ((a) is a top view, (b) is AA sectional drawing) which shows the whole structure of the linear vibration motor which concerns on 3rd Embodiment of this invention. It is explanatory drawing (plan view of the state except a cover frame) which shows the internal structure of the linear vibration motor which concerns on 3rd Embodiment of this invention. It is explanatory drawing ((a) is a top view, (b) is AA sectional drawing) which shows the whole structure of the linear vibration motor which concerns on 4th Embodiment of this invention. It is explanatory drawing (plan view of the state except a cover frame) which shows the internal structure of the linear vibration motor which concerns on 4th 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 each figure, the X direction indicates the vibration direction of the mover, the Y direction indicates the width direction of the mover perpendicular to the X direction, and the Z direction indicates the thickness direction of the mover perpendicular to the X direction. Common parts in the drawings are denoted by the same reference numerals, and redundant description is omitted.

  1 to 3 show a linear vibration motor 1 according to a first embodiment of the present invention. The linear vibration motor 1 includes a movable element 10 including a magnetic pole part 2 and a weight part 3 as a common part in the following embodiments, a frame body 4 that supports the movable element 10 so as to freely reciprocate, and a frame body 4. Is provided between the frame 4 and the movable element 10. The movable element is provided between the frame 5 and the movable element 10. The coil 5 is fixed to the magnetic pole part 2 and applies a driving force to the magnetic pole part 2. And an elastic member 8 that is elastically deformed by 10 reciprocating vibrations.

  The mover 10 includes a movable frame 11 that also serves as the weight portion 3, and a pair of magnets 2 </ b> A and 2 </ b> B are fixed to the movable frame 11. The mover 10 has a rectangular shape whose width in the Y direction in the figure is greater than or equal to the thickness in the X direction in the figure. Specifically, it has a flat shape in which the width in the Y direction in the figure is larger than the thickness in the Z direction in the figure. The magnetic pole portion 2 includes a pair of magnets 2A, 2B and a back yoke 2S, and the pair of magnets 2A, 2B are magnetized in opposite directions along the Z direction (thickness direction of the mover 10). The rear surface is connected to the rear yoke 2S.

  The frame body 4 includes a case frame 40 in which the mover 10 is accommodated and a lid frame 41 that covers the case frame 40. Both ends of one guide shaft 6 are supported in the case frame 40, and the mover 10 has an insertion portion 10 </ b> A through which the guide shaft 6 is inserted and a bearing 13. It is slidably supported along.

  The coil 5 is fixed to the lid frame 41 of the frame body 4 via a flexible substrate 50 on the surface facing the case frame 40. The coil 5 is wound along the support surface 4A of the cover frame 41 (the surface defined by the axial direction of the guide shaft 6 and the width direction of the mover 10), and is a cover made of a magnetic material along the support surface 4A. It is fixed to the frame 41.

  The linear vibration motor 1 is provided with a contact portion 20 where the mover 10 and the frame 4 are in partial contact at a position away from the guide shaft 6 in the width direction (Y direction in the drawing) of the mover 10. In 20, the mover 10 is biased toward the lid frame 41 (frame body 4), which is a magnetic body, by the magnetic force of the magnetic pole part 2. The partial contact of the contact portion 20 is preferably a point contact with a small contact resistance.

  In the example illustrated in FIG. 1, the contact portion 20 is configured by a rolling element 7 that is rotatably held by the support surface 4 </ b> A of the lid frame 41 and the mover 10. In this example, the support surface 4A is provided on the lid frame 41 (frame body 4) side and the rolling element 7 is held on the movable element 10 side. However, the support surface 4A is provided on the movable element 10 side and the lid frame is provided. The rolling element 7 may be held on the 41 (frame 4) side. In the following description, an example in which the rolling element 7 is provided as the contact portion 20 will be described. However, the contact portion 20 is not limited to this, and may be a convex portion provided on the movable element 10 side or the frame body 4 side. Can be formed.

  In the example shown in FIG. 1, the mover 10 includes a rolling element holding unit 12. The rolling element holding portion 12 includes a groove 12A along the guide shaft 6 (parallel to the guide shaft 6), and a rolling element (bearing) 7 is held in the groove 12A. The rolling element 7 is rotatably held by the rolling element holding part 12 on the movable element 10 side, and is arranged between the support surface 4 </ b> A of the frame body 4 (lid frame 41) and the movable element 10. In the rolling element holding part 12, a sliding plate (metal plate) 12B on which the rolling element 7 slides is provided as necessary.

  The elastic member 8 disposed between the mover 10 and the frame 4 is a coil spring in the example of FIGS. 1 to 3, and a pair of coil springs 8 </ b> A and 8 </ b> B are arranged coaxially with the guide shaft 6. 8C and 8D are arranged between the movable frame 11 and the frame body 4 (case frame 40).

  Such a linear vibration motor 1 supplies the coil 5 with a drive current having a resonance frequency determined by the weight of the mover 10 and the spring constant of the elastic member 8, so that the mover 10 moves along the guide shaft 6 and the groove 12A. Reciprocates in a single axis direction. At this time, the mover 10 is urged toward the support surface 4A by a magnetic force (magnetic attraction force) acting between the magnetic pole part 2 (magnets 2A and 2B) and the lid frame 41 that is a magnetic body, so that the guide shaft 6 is one, but always vibrates along the support surface 4A on the lid frame 41. As a result, it is possible to avoid the problem that the mover 10 collides with the frame body 4, the coil 5, etc. and generates abnormal noise. Further, the magnetic pole portion 2 provided on the mover 10 that vibrates slidably along the guide shaft 6 is maintained at a constant distance from the coil 5 by the rolling elements 7, so that stable reciprocating vibration is obtained. be able to.

  The linear vibration motor 1 shown in FIGS. 1 to 3 has a guide shaft 6 disposed at a position shifted from the center of gravity of the mover 10 to one side, and a contact portion 20 disposed at a position shifted from the center of gravity to the other side. Yes. Thereby, rotation around the center of gravity of the mover 10 is suppressed by the guide shaft 6 and the contact portion 20, and stable planar reciprocating vibration can be realized.

  Although the example shown in FIG. 2 has one rolling element 7 in the contact portion 20, as shown in FIG. 3, a plurality of rolling elements 7 may be arranged. When a plurality of rolling elements 7 are arranged, as shown in FIG. 3, it is preferable that a plurality of rolling element holding portions 12 are provided on the mover 10 and the grooves 12 </ b> A are arranged linearly.

  A linear vibration motor 1A shown in FIGS. 4 and 5 is a modification of the linear vibration motor 1 described above. In this linear vibration motor 1A, the frame body 4 is elongated in the X direction (vibration direction), and the mover 10 is flattened with a width in the Y direction larger than the thickness in the Z direction.

  Further, in the linear vibration motor 1 </ b> A, the guide shaft 6 is arranged such that one end side is fixed to the end portion of the mover 10 and protrudes in opposite directions from both end portions of the mover 10. The frame 4 is provided with a bearing 13 that slidably supports the guide shaft 6, and coil springs 8 </ b> A and 8 </ b> B that are arranged coaxially with the guide shaft 6 are arranged between the movable frame 11 and the bearing 13. ing. According to such a linear vibration motor 1A, since the guide shaft 6 does not have to penetrate the mover 10, the magnets 2A and 2B can be arranged in the entire width direction (Y direction) of the mover 10, and the narrow width Even when the movable element 10 is used, a sufficient driving force can be obtained.

  The linear vibration motor 1B shown in FIGS. 6 and 7 is another modification of the linear vibration motor 1 described above. The linear vibration motor 1B includes a pair of magnets 2C and 2D in which the magnetic pole portion 2 is magnetized in the opposite directions along the guide shaft 6, and a spacer yoke 2P disposed therebetween. The coil 5 is wound around the spacer yoke 2P and is fixed to the frame 4 around it. The cover frame 41 is provided with a counter yoke 43 at a position facing the magnetic pole part 2 of the mover 10. The opposing yoke 43 is disposed between the guide shaft 6 and the rolling element 7, but is disposed closer to the rolling element 7.

  The mover 10 of the linear vibration motor 1B is urged toward the support surface 4A by the magnetic force (magnetic attraction force) acting between the magnetic pole portion 2 (magnets 2C, 2D) and the opposing yoke 43, so that the guide shaft 6 Is one, but always vibrates along the support surface 4A on the lid frame 41, and avoids the problem that the mover 10 collides with the frame 4 or the coil 5 to generate abnormal noise. Can do. At this time, the magnetic pole portion 2 in the coil 5 vibrates without contacting the inner surface of the coil 5 by appropriately setting the support position of the end portion of the guide shaft 6 and the size of the rolling element 7.

  The linear vibration motor 1C shown in FIGS. 8 and 9 is a modification of the linear vibration motor 1B described above. In this example, the frame 4 is elongated in the X direction (vibration direction), and two rolling elements 7 are provided on the left and right sides of the magnetic pole part 2.

  Since the mover 10 of the linear vibration motors 1 to 1C described above is slidably supported along the uniaxial guide shaft 6, it has a degree of freedom to rotate around the guide shaft 6. Since the magnetic force of the magnetic pole portion 2 included in the mover 10 is biased toward the support surface 4A side of the frame body 4, the mover 10 is prevented from rotating around the guide shaft 6 and the mover 10 is uniaxially moved. It can be reciprocated along. At this time, since the mover 10 is biased toward the support surface 4A via the rolling element 7 at a position away from the guide shaft 6, the support surface 4A has low friction utilizing the rolling friction of the rolling element 7. Stable vibration on top.

  Such assembly of the linear vibration motors 1 to 1C does not require the parallelism of the two axes to be adjusted with high accuracy unlike the prior art, so that relatively simple assembly is possible. Therefore, a high-efficiency flat linear vibration motor with less mechanical noise can be realized without using high-precision parts.

  FIG. 10 shows a portable information terminal 100 as an example of an electronic device equipped with the linear vibration motor 1 (1A to 1C) according to the embodiment of the present invention. The portable information terminal 100 including the linear vibration motor 1 (1A to 1C) that can obtain a stable vibration and can be thinned and compact in the width direction is different in the operation start / end time of an incoming call or an alarm function in a communication function. It can be transmitted to the user with stable vibration that is less likely to generate sound. Moreover, the portable information terminal 100 which pursued high portability or design can be obtained by making the linear vibration motor 1 (1A to 1C) thin and compact in the width direction. Furthermore, since the linear vibration motor 1 (1A to 1C) has a compact shape in which each part is housed in a rectangular parallelepiped frame 4 with a reduced thickness, the space is efficiently provided inside the thin portable information terminal 100. Can be equipped.

  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. The number and arrangement of the coils and magnets in the above description can be selected as appropriate as long as linear reciprocal vibration is possible. 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, 1C: linear vibration motor,
2: Magnetic pole part, 2A, 2B, 2C, 2D: Magnet,
2S: Back yoke, 2P: Spacer yoke,
3: weight part, 4: frame body, 40: case frame, 41: lid frame, 43: counter yoke,
4A: Support surface, 5: Coil, 50: Flexible substrate,
6: guide shaft, 7: rolling element,
8: Elastic member, 8A, 8B, 8C, 8D: Coil spring,
10: mover, 10A: insertion part,
11: movable frame, 12: rolling element holding portion, 12A: groove, 12B: sliding plate (metal plate),
13: Bearing, 20: Contact part,
100: Portable electronic device (personal digital assistant)

Claims (8)

A mover including a magnetic pole part and a weight part;
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 magnetic pole part;
A guide shaft that regulates vibration of the mover in a uniaxial direction;
An elastic member provided between the frame and the mover and elastically deformed by reciprocating vibration of the mover;
The movable element has a rectangular shape whose width in the direction intersecting the axial direction of the guide shaft is equal to or greater than the thickness in the direction intersecting the axial direction of the guide shaft,
A contact portion where the mover and the frame body are in partial contact with each other at a position away from the guide shaft in the width direction of the mover is provided,
In the contact portion, the movable element is urged toward the frame by the magnetic force of the magnetic pole portion.   The contact portion includes a support surface provided on one side of the frame body and the movable element, and a rolling element that is rotatably held on the other side of the frame body and the movable element. The linear vibration motor according to claim 1, wherein the rolling elements are in contact with each other.   The said guide shaft is arrange | positioned in the position shifted to the one side from the gravity center of the said needle | mover, and the said contact part is arrange | positioned in the position shifted to the other side from the said gravity center. Linear vibration motor. The magnetic pole part includes a pair of magnets magnetized in opposite directions along the thickness direction of the mover,
The said coil is wound along the surface prescribed | regulated by the axial direction of the said guide shaft, and the width direction of the said needle | mover, and is being fixed to the said frame of a magnetic body. The linear vibration motor of any one of these. The magnetic pole part includes a magnet magnetized along the guide shaft,
The linear vibration motor according to claim 1, wherein the coil is wound around the magnetic pole portion. Both ends of the guide shaft are supported by the frame body,
The linear vibration motor according to claim 1, wherein the mover is slidably supported along the guide shaft. The guide shaft has one end fixed to the end of the mover, and is arranged to protrude in opposite directions from both ends of the mover.
The linear vibration motor according to claim 1, wherein the frame body is provided with a bearing that slidably supports the guide shaft.   The portable electronic device provided with the linear vibration motor of any one of Claims 1-7.

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