JP6479595B2 - Linear vibration motor - Google Patents

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, a linear vibration motor capable of generating a relatively large vibration by linear reciprocating vibration has attracted attention. This linear vibration motor is provided with a linear fixed shaft, and by vibrating the mover along this, stable vibration can be obtained, and the mover can be held by the fixed shaft. Damage resistance during impact can be obtained.

  In the conventional technology of a linear vibration motor having a fixed shaft, a weight and a magnet are provided on the mover side, and a drive force (Lorentz force) is applied to the magnet by energizing a coil provided on the stator side. A through hole is formed along the vibration direction, and a single fixed shaft is passed through the through hole (see Patent Document 1 below), or two fixed shafts are provided along the vibration direction. There have been proposed ones in which a coil and a magnet are disposed between fixed shafts and a mover is slidably supported by two fixed shafts (see Patent Document 2 below).

JP 2012-16153 A JP 2011-97747 A

  As portable electronic devices and wearable electronic devices become smaller and thinner, vibration motors installed therein are required to be further reduced in size and thickness. In particular, in an electronic device having a flat panel display unit such as a smart phone, the space in the device in the thickness direction perpendicular to the display surface is limited. There is.

  When thinning a linear vibration motor with a fixed shaft, as in the former prior art, a through-hole is formed in the mover with a weight connected to a magnet along the vibration direction. Then, a through-hole is formed in the magnet itself, and in order to secure a sufficient volume of the magnet to obtain a desired driving force, the thickness of the magnet is sufficiently increased with respect to the diameter of the fixed shaft. It will be necessary. Furthermore, since the drive unit is configured by further arranging a coil around the magnet, there is a problem that it cannot sufficiently cope with the reduction in thickness.

  In the case of providing the two fixed shafts and disposing the coil and the magnet between them as in the latter prior art described above, it is not necessary to form a through hole in the magnet, so that the magnet can be made thinner. However, since two fixed shafts are provided on both sides of the magnet, there arises 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.

  In order to cope with this, it is conceivable to divide the shafts on both sides in one axial direction of the magnet and vibrate the mover along the guide shafts arranged coaxially. In this case, since the shaft does not penetrate the magnet, the volume reduction of the magnet due to the through hole can be eliminated. However, since the shaft does not penetrate, a radial load is received only by the mover when an impact is applied, and the connecting portion between the magnet and the weight is easily divided. When the weight is a metal that is difficult to weld, such as a tungsten alloy, the welding strength between the magnet and the weight cannot be increased, and this problem becomes more obvious.

  This invention makes it an example of a subject to cope with such a problem. In other words, by providing a guide shaft, it is possible to reduce the volume of the magnet while reducing the thickness of the magnet or making it compact in the width direction while enjoying the advantages of stable vibration and excellent impact strength. In addition, an object of the present invention is to obtain a mover in which the magnet and the weight are difficult to be separated even when an impact is applied.

In order to achieve such an object, a linear vibration motor according to the present invention has the following configuration.
Movable element including a magnet part and a weight part, a frame body that accommodates the movable element, a coil that is fixed to the frame body and drives the magnet part along a uniaxial direction, and a driving force applied to the magnet part An elastic member that imparts an elastic force repelling to the movable element, a guide shaft that is disposed on both sides of the uniaxial direction of the magnet part and guides vibration along the uniaxial direction of the movable part, and the magnet part; A connecting member that connects the weight part, and the connecting member has a fitting hole, and an end of the magnet part is fitted in the fitting hole. Vibration motor.

  The linear vibration motor of the present invention having such characteristics can obtain stable vibration, and can be thinned or compact in the width direction. In particular, even when a metal that is difficult to weld to the weight part is used while suppressing the volume reduction of the magnet part while preventing the shaft from penetrating the magnet part, the magnet part and the weight part are firmly connected via the connecting member. It can be welded and the impact strength can be increased.

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 (disassembled perspective view) which showed the needle | mover of the linear vibration motor which concerns on embodiment of this invention. It is explanatory drawing (cross-sectional view) which showed the needle | mover of the linear vibration motor which concerns on embodiment of this invention. It is explanatory drawing (decomposed perspective view) which showed the linear vibration motor which concerns on other 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 will be omitted). 1 to 4 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 2 that houses the mover 10, and a coil 3 that is fixed to the frame 2 and drives the magnet part 4 along a uniaxial direction. And an elastic member 6 that applies an elastic force repelling the driving force applied to the magnet unit 4 to the mover 10.

  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. Moreover, the frame 2 is equipped with the cover plate 2Q which covers the accommodation in the frame 2 as needed. 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 member 5 is fixed to the side surface of the magnet part 4, thereby increasing the rigidity of the magnet part 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), and one end side thereof is fixed to the weight portion 7 and the other end side protrudes in the opposite direction to form a free end. Yes. 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. The pair of guide shafts 8 need only be along one axial direction, and their central axes may be arranged in parallel.

  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 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 a support protrusion 2P provided on the side walls 2B and 2C of the frame 2, and the other end of the elastic member 6 is connected to a support protrusion 7A1 provided on the end portion 7A of the weight portion 7. It is locked.

  A metal reinforcing member 5 disposed along a uniaxial direction (X direction in the drawing) is fixed to the magnet portion 4 by adhesion or the like. Thus, the plurality of magnet pieces 4A, 4B, 4C and the spacer yokes 4D, 4E are reinforced integrally. On the other hand, the connecting member 11 that connects the magnet portion 4 and the weight portion 7 is made of metal. As shown in FIG. 4, the reinforcing member 5 and the connecting member 11 are laser-welded at the connection point P1. Yes. Moreover, the connection member 11 and the weight part 7 are laser-welded in the connection location P2.

  As for the connection location P2, the end surface of the connection member 11 and the side surface of the weight part 7 are welding surfaces, and are flush. And the laser irradiation in the connection location P2 is performed in the extension direction of the connection member 11 orthogonal to a uniaxial direction. By thus laser welding the connecting member 11 and the weight part 7, even if the weight part 7 is a metal material that is difficult to weld (high melting point) such as a tungsten alloy, the connecting member 11 comes before the weight part 7. Without melting, it becomes possible to perform strong bonding by laser welding. As the metal material of the connecting member 11, it is preferable to select a material having an intermediate melting point between the metal material of the weight portion 7 and the metal material of the reinforcing member 5. Further, the connecting member 11 can be directly welded not only to the reinforcing member 5 but also to the magnet portion 4 (magnet pieces 4A and 4C).

  The coupling member 11 has a fitting hole 11B opened at the center, and the end of the magnet part 4 (magnet pieces 4A, 4C) is fitted into the fitting hole 11B. In this way, by fitting the end of the magnet part 4 into the fitting hole 11B of the connecting member 11, the positioning of the weight part 7 and the center of gravity of the magnet part 4 can be easily performed. And the magnet part 4 can be connected efficiently.

  The connecting member 11 includes an abutting portion 11A that protrudes to the inner surface side (the bottom surface 2A side) of the frame body 2. By providing the contact portion 11A, when the mover 10 rotates around the guide shaft 8, only the contact portion 11A that is a part of the connecting member 11 contacts the slide receiving portion 2R on the bottom surface 2A, and the weight The portion 7 does not contact the inner surface of the frame body 2. Since it is difficult to process the surface of the weight part 7 with low friction, when the weight part 7 comes into contact with the inner surface of the frame body 2 and slides, the sliding load increases and the generation of abnormal noise also increases. The contact portion 11A of the connecting member 11 that is easy to process smoothly slides on the slide receiving portion 2R, so that smooth and quiet vibration can be obtained, and further the life of the linear vibration motor 1 can be extended. .

  FIG. 5 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. Thus, the pair of guide shafts 8 is cantilevered with respect to the frame 2, and the magnet 4 is disposed on the extended line on the free end side (the other end side).

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

  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. Due to the elastic repulsive force, the mover 10 reciprocates along one axis.

  In the linear vibration motor 1, since the pair of guide shafts 8 do not penetrate the magnet unit 4, a sufficient driving force is provided by the magnet unit 4 that is wide in the Y direction and thin in the Z direction regardless of the diameter of the pair of guide shafts 8. The obtained magnet volume can be secured. 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 guide shafts 8 is provided on the left and right sides of the magnet unit 4 as 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 no space for shaft arrangement is required, 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.

  At this time, it is conceivable that the mover 10 supported by the pair of guide shafts 8 rotates around the pair of guide shafts 8 and the left and right sides of the mover 10 swing up and down. For this, the lower part of the connecting member 11 that connects the weight part 7 and the magnet part 4 is provided so as to protrude from the weight part 7 as an abutting part 11A, and on the inner surface of the frame body 2, the connecting member 11 A slide receiving portion 2R with which the contact portion 11A slides is provided. According to this, by forming the sliding receiving portion 2R with a resin material or the like, it is possible to suppress the occurrence of abnormal noise even when the contact portion 11A of the connecting member 11 contacts the inner surface of the frame body 2. , Can maintain stable vibration.

  As described above, the linear vibration motor 1 according to the embodiment of the present invention causes the movable element 10 to be axially supported by the pair of guide shafts 8 and vibrates, so that stable vibration can be obtained as in the case where the fixed shaft is provided. It is possible to obtain damage resistance at the time of dropping impact.

  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. It can be transmitted 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. . Moreover, since the linear vibration motor 1 has high impact resistance strength and high durability, it is possible to obtain the portable information terminal 100 that has a long life and hardly breaks down.

  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: cover plate, 2R: sliding receiving part,
3: Coil, 4: Magnet part,
4A, 4B, 4C: Magnet pieces,
4D, 4E: Spacer yoke,
5: Reinforcing member, 6: Elastic member,
7: weight part, 7A: end part, 7A1: support protrusion,
7B: guide shaft support, 7C: hole,
8: guide shaft, 9: bearing, 10: mover,
11: connecting member, 11A: contact portion, 11B: fitting hole,
100: Portable information terminal

Claims (5)

A mover including a magnet part and a weight part;
A frame housing the mover;
A coil that is fixed to the frame and drives the magnet portion along a uniaxial direction;
An elastic member that imparts to the mover an elastic force that repels the driving force applied to the magnet portion;
Guide shafts arranged on both sides in the uniaxial direction of the magnet part and guiding vibration along the uniaxial direction of the mover;
A connecting member for connecting the magnet part and the weight part ;
The connecting member has a fitting hole, and the end of the magnet part is fitted into the fitting hole .   The linear vibration motor according to claim 1, wherein the connecting member is made of metal and is welded to the metal weight portion. A metal reinforcing member disposed along the uniaxial direction is fixed to the magnet portion,
The linear vibration motor according to claim 2, wherein the connecting member is welded to the reinforcing member. The said connection member is provided with the contact part which protruded in the inner surface side of the said frame, and a corresponding contact part contact | abuts to the sliding receiving part provided in the inner surface of the said frame. The linear vibration motor of any one of Claims . A portable information terminal comprising the linear vibration motor according to claim 1 .

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