JP2017017875A - Linear vibration motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow for thinning of a linear vibration motor, and to obtain stabilized vibration free from rattling, by inhibiting generation of operating sound (abnormal noise) due to rotation of a mover about the vibration axis, even when the mover is made flat.SOLUTION: A linear vibration motor 1 includes a mover 10 having a magnet 4 and a weight 7, a frame body 2 for supporting the mover 10 slidably in the uniaxial direction, a coil 3 fixed to the frame body 2 and driving the magnet 4 in the uniaxial direction, an elastic member 6 for imparting an elastic force, repelling a driving force imparted to the magnet 4, to the mover 10, and a guide shaft 8 placed coaxially with the center of gravity axis of the mover 10, and guiding the vibration of the mover 10. The frame body 2 includes a magnetic force attraction part (magnetic plate 12) for magnetically attracting the mover 10 in one direction around the guide shaft 8, and a sliding supporting part (nonmagnetic sliding plate 13) for sliding and supporting a part of the mover 10.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a linear vibration motor.

  Vibration motors (or vibration actuators) are widely used as devices that are built in portable electronic devices and transmit signal generation such as incoming calls and alarms to vibration carriers by vibrations. , Has become an indispensable device. In recent years, a vibration motor has attracted attention as a device that realizes haptics (skin sensation feedback) in a human interface such as a touch panel.

  As various types of vibration motors have been developed, attention has been paid to linear vibration motors that can generate relatively large vibrations by linear reciprocating vibration of the mover. 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 the desired driving force and the mass of the weight is sufficiently secured to obtain the 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 mass of the weight. In this case, if the mover rotates around the linear vibration axis, the flat mover has a shape in which the side part easily collides with the surrounding frame body due to the rotation. Occurring and operating noise occurs, and there is a problem that stable operation cannot be obtained due to rattling due to rotation.

  For this reason, the prior art provides two fixed shafts to suppress rotation around the vibration axis of the mover and realizes stable linear vibration. However, when two fixed shafts are provided, two fixed shafts are arranged on both sides of the magnet, which causes a problem that the width of the linear vibration motor becomes large. In recent years, linear vibration motors equipped in miniaturized electronic devices are required to be more compact not only in the thickness direction but also in the width direction. Furthermore, since it is necessary to ensure the parallelism of the two guide shafts and high accuracy is required for assembly, 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. That is, enabling the linear vibration motor to be thinned, and preventing the mover from rotating around the vibration axis and generating operating noise (abnormal noise) even when the mover is made flat. It is an object of the present invention to obtain stable vibration without rattling, to make the thickness and width compact, and to improve productivity.

In order to achieve such an object, a linear vibration motor according to the present invention has the following configuration.
A mover including a magnet part and a weight part, a frame that supports the mover slidably along a uniaxial direction, and a coil that is fixed to the frame and drives the magnet part along the uniaxial direction. An elastic member that imparts an elastic force repelling the driving force applied to the magnet portion to the mover, and a guide shaft that is arranged coaxially with the center of gravity axis of the mover and guides the vibration of the mover. And the frame includes a magnetic force attracting part for attracting the movable element in one direction around the guide shaft, and a sliding support part for slidingly supporting a part of the movable element. Vibration motor.

  The linear vibration motor of the present invention having such a feature can be thinned by the shape of the mover, and even when the mover has a flat cross-sectional shape, a part of the mover slides the sliding support portion. Since it vibrates while moving, it is possible to prevent the moving element from rotating around the vibration axis to generate an operating noise (abnormal noise), and to obtain a stable vibration without rattling. At this time, since the parallel adjustment of the shaft can be made unnecessary by the single shaft, the high assembly accuracy can be eliminated and the productivity can be improved. Further, by using a uniaxial guide shaft, it is possible to achieve compactness in the thickness direction and the width direction.

It is explanatory drawing (decomposed perspective view) which showed the linear vibration motor which concerns on embodiment of this invention. It is explanatory drawing (sectional drawing) which showed the linear vibration motor which concerns on embodiment of this invention. It is explanatory drawing (sectional drawing) which showed the linear vibration motor which concerns on embodiment of this invention. It is explanatory drawing (disassembled perspective view) which showed the other form example of the linear vibration motor which concerns on embodiment of this invention. It is explanatory drawing which showed the electronic device (mobile information terminal) equipped with the linear vibration motor which concerns on embodiment of this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings (hereinafter, the same reference numerals in different drawings indicate the same parts, and repeated descriptions in the respective drawings are omitted). 1 to 3 show the overall configuration of a linear vibration motor according to an embodiment of the present invention. The X direction in each figure indicates the vibration direction (uniaxial direction), the Y direction indicates the width direction, and the Z direction indicates the thickness (height) direction.

  The linear vibration motor 1 includes a mover 10 having a magnet part 4 and a weight part 7, a frame body 2 that supports the mover 10 slidably along one axial direction, and a magnet part 4 fixed to the frame body 2. A coil 3 that is driven along a uniaxial direction and an elastic member 6 that imparts an elastic force repelling the driving force applied to the magnet unit 4 to the mover 10 are provided.

  The frame body 2 only needs to have a frame configuration that can accommodate each part, but in the illustrated example, the frame body 2 includes side walls 2B, 2C, 2D, and 2E that are erected around the rectangular bottom surface 2A. ing. The frame body 2 includes a cover plate 2Q that covers the contents in the frame body 2. The lid plate 2Q is formed in a rectangular plate shape that is attached to the upper end surfaces of the side walls 2B to 2E. The frame 2 can be formed by processing (pressing or the like) a metal plate. In the example shown in the drawing, the frame body 2 is a thin shape in which the dimension in the thickness direction (Z direction in the figure) is smaller and the dimension in the vibration direction (X direction in the figure) is larger than the dimension in the width direction (Y direction in the figure). It has a substantially rectangular parallelepiped shape (box shape).

  In the linear vibration motor 1, a drive unit is configured by a coil 3 fixed to the frame body 2 and a magnet unit 4 which is a part of the mover 10. A Lorentz force (driving force) along a uniaxial direction (X direction in the drawing) is applied to the magnet unit 4 by inputting a vibration generating current from the signal input unit 2A1 provided in the frame 2 to the coil 3 fixed to the frame 2. ) Acts.

  The magnet unit 4 includes a plurality of flat rectangular magnet pieces 4A, 4B, and 4C having a polarity along a uniaxial direction (X direction in the drawing) so that the same poles face each other, and the spacer yokes 4D and 4E are interposed therebetween. It is something that is sandwiched and joined. A reinforcing plate 5 is fixed to the side surface of the magnet unit 4 as necessary, thereby increasing the rigidity of the magnet unit 4.

  The coil 3 is obtained by winding an electric wire along the Y and Z directions around the magnet portion 4 with the magnetic pole direction in the X direction, and one or both of the upper surface and the lower surface, and further, if necessary. The side surface is fixed to the inner surface of the frame body 2. The coil 3 may be fixed to the frame 2 directly, or the coil 3 may be wound around a coil bobbin and the coil bobbin may be fixed to the frame 2.

  In the illustrated example, the mover 10 has the weight portion 7 connected to both ends of the magnet portion 4 in one axial direction (X direction in the drawing). The weight portion 7 can be made of a metal material having a high specific gravity (for example, tungsten). In the illustrated example, the weight portion 7 has a height in the Z direction larger than the thickness of the magnet portion 4 and is larger than the width of the magnet portion 4. It has a rectangular cross-sectional shape having a width in the Y direction. The weight portion 7 is connected to the magnet portion 4 via the connecting member 11.

  A pair of guide shafts 8 are pivotally supported on the frame body 2. The pair of guide shafts 8 is divided and arranged along a uniaxial direction (X direction in the drawing), one end side thereof is fixed to the weight portion 7, and the other end sides protrude in opposite directions to form a free end. The guide shaft 8 is disposed coaxially with the center of gravity axis of the mover 10 and guides the vibration of the mover 10 along a uniaxial direction. Here, the guide shaft 8 is divided and arranged, but the guide shaft 8 may be fixed through the magnet portion 4 or may be slidably supported through the magnet portion 4.

  The weight portion 7 includes a guide shaft support portion 7 </ b> B for supporting the guide shaft 8. The guide shaft support portion 7B is a portion that is recessed along the uniaxial direction from the end portion 7A of the weight portion 7, and the guide shaft 8 supported at one end side by the guide shaft support portion 7B is on the bottom surface 2A of the frame body 2. The bearing 9 attached via the support portion 2S is supported so as to be slidable along a uniaxial direction (X direction in the drawing). At this time, the guide shaft support portion 7B of the weight portion 7 has a width sufficient to accommodate the bearing 9, and a large amplitude of the movable element 10 is ensured by the bearing 9 entering the guide shaft support portion 7B. doing.

  The frame 2 includes a magnetic force attracting part (magnetic plate 12) for attracting the mover 10 in one direction around the guide shaft 8 and a sliding support part (non-magnetic sliding) for slidingly supporting a part of the mover 10. Plate 13). That is, the frame 2 itself is made of a non-magnetic material, and a magnetic attraction portion is formed by disposing the magnetic plate 12 extending in the X direction in the drawing at the end in the Y direction in the drawing on the inner surface of the lid plate 2Q. The nonmagnetic sliding plate 13 is disposed on the bottom surface (inner surface) 2A of the frame body 2 to form a sliding support portion.

  The magnetic plate 12 is formed of an iron plate or the like and is attached at a position away from the center of gravity axis G of the mover 10. The non-magnetic sliding plate 13 is made of a non-magnetic and high-strength base material such as titanium or copper, which is coated with a high hardness and high sliding (low friction) surface coating such as chrome plating. Can do.

  In the illustrated example, the magnetic attraction portion is formed by the magnetic plate 12 and the sliding support portion is formed by the non-magnetic sliding plate 13, but not limited to this, a magnetic film is partially formed on the inner surface of the lid plate 2Q. Alternatively, a magnetic film may be applied to form a magnetic force attracting part, or a part of the bottom plate 2A may be provided with a low friction / high strength coating to form a sliding support part.

  As shown in FIG. 3, the mover 10 has a long side with a cross-sectional shape that intersects in a uniaxial direction (X direction in the drawing). Specifically, the mover 10 has a rectangular cross section having a long side and a short side. The frame body 2 includes a pair of inner surfaces (the inner surface and the bottom surface 2A of the cover plate 2Q) facing each other along the long side thereof, and one side of the inner surface (in the illustrated example, the inner surface side of the cover plate 2Q). A magnetic force attracting part (magnetic plate 12) for attracting the magnet part 4 is provided, and a sliding support part (nonmagnetic sliding plate 13) is provided on the other side (bottom surface 2A side) of the inner surface.

  The connecting member 11 that connects the magnet portion 4 and the weight portion 7 has a shape that protrudes toward the bottom surface 2 </ b> A with respect to the magnet portion 4 and the weight portion 7. As a result, when the mover 10 rotates around the guide shaft 8 coaxial with the center of gravity axis G, a part of the connecting member 11 comes into contact with the sliding support portion (nonmagnetic sliding plate 13) on the bottom surface 2A. Become.

  In the illustrated example, the cross-sectional shape that intersects the uniaxial direction (X direction in the drawing) of the magnet portion 4 and the weight portion 7 has a long side (and a short side), and the connecting member 11 is a part ( In a state where the contact portion 11A is in contact with the sliding support portion (nonmagnetic sliding plate 13), the long sides of the magnet portion 4 and the weight portion 7 are the inner surfaces of the frame body 2 (the inner surface and the bottom surface 2A of the lid plate 2Q). The magnet portion 4 and the weight portion 7 are coupled so as to be substantially parallel to the head).

  The elastic member 6 is arranged non-coaxially with the pair of guide shafts 8 along the uniaxial direction, and gives the movable element 10 an elastic force repelling a driving force generated by the coil 3 and the magnet unit 4. In the illustrated example, a coil spring that extends and contracts along the uniaxial direction (X direction) is used as the elastic member 6, and two elastic members 6 on one side are placed between the weight portion 7 and the side walls 2 </ b> B and 2 </ b> C of the frame body 2. Intervene. In the illustrated example, the elastic member 6 is disposed in parallel with the pair of guide shafts 8. One end of the elastic member 6 is locked to the support protrusion 2P provided on the side walls 2B and 2C of the frame body 2, and the other end of the elastic member 6 is engaged with the support protrusion provided on the end portion 7A of the weight portion 7. It has been stopped.

  The operation of such a linear vibration motor 1 will be described. When not driven, the mover 10 is stationary at the vibration center position where the elastic force of the elastic member 6 is balanced. When a vibration generating current having a resonance frequency determined by the mass of the mover 10 and the elastic coefficient of the elastic member 6 is input to the coil 3, a driving force in the X direction is applied to the magnet unit 4. The elastic repulsive force causes the mover 10 to reciprocate along a uniaxial direction (X direction in the drawing).

  At this time, the mover 10 is moved around the guide shaft 8 coaxial with the center of gravity axis G by the magnetic attraction between the magnetic plate 12 and the magnet unit 4 disposed at a position away from the center of gravity G of the mover 10. A rotational force in the direction is applied, and the end of the long side in the cross-sectional shape of the mover 10 is pulled toward the cover plate 2Q side. The mover 10 has, for example, a square shape in cross section perpendicular to the guide shaft 5.

  Further, since the connecting member 11 that connects the magnet portion 4 and the weight portion 7 of the mover 10 includes the abutting portion 11A that protrudes downward, the abutting portion 11A is caused by the rotational force around the guide shaft 8. It will contact | abut on the nonmagnetic sliding plate 13 provided on the bottom face 2A, will contact on the nonmagnetic sliding plate 13 with low friction, and will slide on it. At this time, the upper side of the mover 10 is not in contact with the inner surface of the cover plate 2Q.

  According to this, the movable element 10 is urged to rotate in one direction around the guide shaft 8 by magnetic attraction between the magnetic plate 12 and the magnet portion 4 during reciprocating vibration along the guide shaft 8, and a part of the movable element 10 That is, the abutting portion 11A slides on the nonmagnetic sliding plate 13 in a constantly abutting state. As a result, the mover 10 can operate stably without rattling, and the linear vibration motor 1 can be obtained in which the operation noise (abnormal noise) during vibration is reduced.

  According to such a linear vibration motor 1, the nonmagnetic sliding plate 13 on which the abutting portion 11A slides is reduced in sliding wear, so that the life of the linear vibration motor 1 can be extended. . Further, when the mover 10 rotates around the guide shaft 8, the contact portion 11 </ b> A always contacts the nonmagnetic sliding plate 13, and the mover 10 contacts the other part of the frame body 2. Since this can be avoided, deformation at the time of impact can be suppressed, and the linear vibration motor 1 having an impact resistant structure can be obtained. In addition, since the nonmagnetic sliding plate 13 has a higher hardness base material than the frame 2 and a high hardness surface coating (surface treatment), the impact resistant structure is not affected by the material of the frame 2. Can be improved.

  Further, in this linear vibration motor 1, the pair of guide shafts 8 are divided and do not penetrate the magnet portion 4, so that the magnet portion is wide in the Y direction and thin in the Z direction regardless of the diameter of the pair of guide shafts 8. 4 can secure a magnet volume that can provide a sufficient driving force. Thereby, a thin linear vibration motor 1 capable of obtaining a sufficient driving force can be obtained.

  Furthermore, the linear vibration motor 1 that axially supports the mover 10 with a pair of coaxially arranged guide shafts 8 is compared with the conventional technique in which a pair of fixed shafts along the vibration direction are provided on the left and right sides of the magnet. Since the space for the shaft arrangement is not necessary on the left and right of the portion 4, the left and right widths can be made compact.

  Furthermore, since the elastic member 6 is arranged non-coaxially with respect to the pair of guide shafts 8, the diameter of the elastic member 6 can be reduced regardless of the diameter of the pair of guide shafts 8. The setting of the elastic force when the diameter of the elastic member 6 is reduced can be appropriately set by selecting the material of the elastic member 6 or arranging a large number of elastic members 6 in parallel. This also makes it possible to reduce the thickness of the linear vibration motor 1 that axially supports the mover 10.

  FIG. 4 shows another example of the linear vibration motor 1 according to the embodiment of the present invention. In this example, one end side of the pair of guide shafts 8 is fixed to the frame body 2 and the other end side is slidably supported on the movable element 10 side, but other configurations are the same as the above-described example.

  One end side of the pair of guide shafts 8 is supported by the frame body 2 at two points in the illustrated example. Specifically, the end portion of the guide shaft 8 is fixed to the side walls 2 </ b> B and 2 </ b> C of the frame body 2, and is further supported by the support portion 2 </ b> S away from the end portion of the guide shaft 8.

  The mover 10 is provided with a hole 7C into which the free end side (the other end side) of the guide shaft 8 is inserted along a uniaxial direction (X direction in the drawing). A bearing 9 in which the guide shaft 8 is slidable in the X direction is provided in the hole 7C, whereby the other end of the guide shaft 8 is slidably supported by the bearing 9 of the mover 10. . The hole 7 </ b> C provided in the mover 10 is provided in the weight part 7 of the mover 10, and no hole is provided in the magnet part 4 of the mover 10.

  The weight portion 7 of such a linear vibration motor 1 can be formed in a rectangular parallelepiped shape, and a hole 7B only needs to be formed in the inside thereof so that the guide shaft 8 passes therethrough. Can be bigger. Thereby, it is possible to sufficiently secure the mass of the mover 10 that becomes the inertial force of vibration.

  As described above, the linear vibration motor 1 according to the embodiment of the present invention can make the linear vibration motor thinner by making the thickness dimension of the mover 10 smaller than the width dimension. Thus, even when the mover 10 is flattened, it is possible to prevent the mover 10 from rotating around the guide shaft 8 and generating an operating noise (abnormal noise). As a result, stable vibration without rattling can be obtained, and productivity can be improved as compared with the case of providing a biaxial parallel fixed shaft.

  In addition, by supporting the movable element 10 by the pair of guide shafts 8 and vibrating the same, stable vibration can be obtained as in the case of providing the fixed shaft, and damage resistance at the time of dropping impact can be obtained. . In such a linear vibration motor 1, it is possible to achieve a reduction in thickness and a reduction in width in the width direction while suppressing volume reduction of the magnet portion 4 and the weight portion 7.

  FIG. 5 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 2 with a reduced thickness, the linear vibration motor 1 can be efficiently installed inside 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: Linear vibration motor,
2: frame, 2A: bottom, 2A1: signal input unit,
2B, 2C, 2D, 2E: side wall, 2S: support part,
2P: support protrusion, 2Q: lid plate,
3: Coil, 4: Magnet part,
4A, 4B, 4C: Magnet pieces,
4D, 4E: Spacer yoke,
5: Reinforcing plate, 6: Elastic member,
7: weight part, 7A: end part, 7B: guide shaft support part, 7C: hole,
8: guide shaft, 9: bearing, 10: mover,
11: connecting member, 11A: contact portion, 12: magnetic plate, 13: non-magnetic sliding plate,
100: Portable information terminal

Claims (7)

A mover including a magnet part and a weight part;
A frame that slidably supports the mover along a uniaxial direction;
A coil that is fixed to the frame and drives the magnet portion along the uniaxial direction;
An elastic member that imparts to the mover an elastic force that repels the driving force applied to the magnet portion;
A guide shaft that is arranged coaxially with the center of gravity axis of the mover and guides the vibration of the mover;
The frame includes a magnetic force attracting part for attracting the mover in one direction around the guide shaft and a sliding support part for slidingly supporting a part of the mover. . The mover has a long side with a cross-sectional shape intersecting the uniaxial direction,
The frame includes a pair of inner surfaces facing along the long side,
The linear vibration motor according to claim 1, wherein the magnetic force attracting part that attracts the magnet part is provided on one side of the inner surface, and the sliding support part is provided on the other side of the inner surface. The frame is a non-magnetic material,
The linear vibration motor according to claim 1, wherein the magnetic force attracting part is a magnetic plate attached at a position away from the center of gravity axis.   The linear vibration motor according to claim 1, wherein a non-magnetic sliding plate provided with a low friction coating is provided on the sliding support portion.   The said magnet part and the said weight part are connected through a connection member, and a part of said connection member contact | abuts to the said sliding support part, The Claim 1 characterized by the above-mentioned. Linear vibration motor. The magnet part and the weight part have long sides in a cross-sectional shape intersecting the uniaxial direction,
The linear vibration motor according to claim 5, wherein the long side is substantially parallel to the inner surface of the frame body in a state where the contact portion is in contact with the sliding support portion.   The portable electronic device provided with the linear vibration motor of any one of Claims 1-6.

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