JP2018046619A - Linear vibration motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize a frictional contact state of a bearing to stabilize a rise time of a linear vibration motor. A linear vibration motor (1) includes a frame body (2), a magnet portion (4), and a weight portion (7), and the frame body (2) is elastically supported by a frame body (2) in a uniaxial direction. A coil 3 that is fixed and reciprocates the mover 10 in the uniaxial direction by energizing a drive signal, a shaft 8 that is fixed to the mover 10 and guides the vibration of the mover 10 along the uniaxial direction, and a frame 2. A bearing 9 that is fixed and slidably supports the shaft 8 is provided, and one of the shaft support 9B and the shaft 8 included in the bearing 9 is a hard magnetic material and the other is a soft magnetic material. [Selection diagram] Fig. 3

Description

  The present invention relates to a linear vibration motor.

  Vibration motors (or vibration actuators) are widely used as devices that are built into portable electronic devices and transmit signal generations 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. A child is reciprocated in a uniaxial direction (see Patent Document 1 below).

Japanese Patent Laid-Open No. 2016-13554

  In such a linear vibration motor, in order to suppress the generation of operating noise and operate the linear vibration motor in a stable state, the mover is moved along a shaft extending in one axial direction as in the conventional example described above. It is effective to vibrate.

  When the mover is slidably supported along the shaft, a slide bearing is provided on the mover, and the shaft is passed through this. At this time, in the conventional linear vibration motor, the contact surface between the bearing and the shaft becomes a lubrication surface with oil interposed therebetween. Therefore, there is a problem that the movement of the mover changes with time. Such a problem becomes conspicuous at the time of the vibration rising from the static contact state to the dynamic friction state, and there is a problem that the rising time of the linear vibration motor is likely to vary.

  The present invention has been proposed to address such problems. That is, an object of the present invention is to stabilize the frictional contact state of the bearing and stabilize the rise time of the linear vibration motor.

  In order to solve such a problem, a linear vibration motor according to the present invention has the following configuration.

  A movable body that includes a frame, a magnet portion, and a weight portion, and is elastically supported by the frame so as to vibrate freely along a uniaxial direction. The movable member is fixed to the frame and is uniaxially driven by energization of a drive signal. A coil that reciprocally vibrates, a shaft that guides the vibration of the mover along one axial direction, and a bearing that slidably supports the shaft, and the shaft support and the shaft that the bearing includes, A linear vibration motor characterized in that one is a hard magnetic material and the other is a soft magnetic material.

It is explanatory drawing which showed the whole structure of the linear vibration motor which concerns on embodiment of this invention. It is explanatory drawing (sectional drawing) which showed the whole structure of the linear vibration motor which concerns on embodiment of this invention. It is sectional drawing which showed the bearing and shaft in the linear vibration motor which concerns on embodiment of this invention. It is explanatory drawing which showed the whole structure of the linear vibration motor which concerns on other embodiment of this invention. It is explanatory drawing which showed the portable electronic device carrying 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. The same reference numerals in the following different drawings indicate parts having the same function, and repeated description in each figure will be omitted as appropriate. 1 and 2 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 frame body 2, a magnet section 4, and a weight section 7, and is fixed to the frame body 2 and a mover 10 that is elastically supported by the frame body 2 so as to vibrate along a uniaxial direction. A coil 3 that reciprocally vibrates the mover 10 in a uniaxial direction by energizing a signal, a shaft 8 that guides the vibration of the mover 10 along the uniaxial direction, and a bearing 9 that slidably supports the shaft 8 are provided. ing.

  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).

  The coil 3 fixed to the frame 2 is obtained by winding an electric wire along the Y and Z directions around the magnet portion 4 with the magnetic poles oriented in the X direction, and one or both of the upper surface and the lower surface thereof. Further, the side surface is fixed to the inner surface of the frame 2 as necessary. 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.

  The magnet portion 4 in the mover 10 is formed by arranging a plurality of flat rectangular magnet pieces 4A, 4B, 4C having a polarity along one axis direction (X direction in the drawing) so that the same poles face each other, and spacers 4D, 4E. Are combined with a gap between them. A reinforcing member 5 is fixed to the side surface of the magnet part 4, thereby increasing the rigidity of the magnet part 4.

  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.

  In the example shown in FIGS. 1 and 2, the shaft 8 is fixed to the movable element 10 and is slidably supported by a bearing 9 fixed to the frame body 2. In this example, the shaft 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 side protrudes in the opposite direction to form a free end. ing. The 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. In addition, the shaft 8 should just be along the uniaxial direction, and the central axis may be provided in parallel.

  The weight portion 7 includes a shaft support portion 7B for supporting the shaft 8. The 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 shaft 8 whose one end is supported by the shaft support portion 7B is supported by the bottom surface 2A of the frame body 2S. Is supported so as to be slidable along a uniaxial direction (X direction in the drawing). At this time, the shaft support portion 7B of the weight portion 7 has a width sufficient to accommodate the bearing 9, and the bearing 9 enters the shaft support portion 7B to ensure a large amplitude of the movable element 10. Yes.

  The elastic member 6 that elastically supports the mover 10 on the frame 2 is arranged non-coaxially with the shaft 8 along the uniaxial direction, and can move an elastic force repelling a driving force generated by the coil 3 and the magnet unit 4. Granted to child 10. 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 shaft 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.

  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. The coil 3 fixed to the frame 2 is energized with a drive signal from the signal input unit 2A1 provided on the frame 2, so that the Lorentz force (drive force) along the uniaxial direction (X direction in the drawing) is applied to the magnet unit 4. Works. The drive signal energized to the coil 3 is an alternating current having a resonance frequency (natural frequency) determined by the elastic coefficient of the elastic member 6 and the mass of the mover 10. The drive force generated by this drive signal and the elastic member 6 Due to the elastic repulsion force, the mover 10 reciprocates in one axis.

  In such a linear vibration motor 1, the bearing 9 that slidably supports the shaft 8 includes a bearing housing 9 </ b> A and a shaft support 9 </ b> B, as shown in FIG. 3. The shaft 8 is formed of a hard magnetic material (permanent magnet), and the shaft 8 is formed of a soft magnetic material. The soft magnetic material here refers to a magnetic material in which the magnetic pole disappears or reverses relatively easily, and refers to a material (such as steel) that is magnetically attracted to the hard magnetic material. The bearing 9 is an oil-impregnated bearing, and the shaft support 9B is two-pole magnetized in a direction perpendicular to the uniaxial direction.

  According to the linear vibration motor 1 including the shaft 8 and the bearing 9, the shaft 8 is slid in contact with the shaft support 9 </ b> B while being always magnetically attracted to the shaft support 9 </ b> B of the bearing 8. Move. Naturally, there is a gap between the outer peripheral surface of the shaft 8 and the inner surface of the shaft support 9B. However, when the shaft 8 slides in one direction of the shaft support 9B, The lubrication state between them is kept constant by boundary lubrication, and stable sliding characteristics can be obtained. As a result, the sliding characteristic of the shaft 8 becomes stable at the time of the vibration rising from the static contact state to the dynamic friction state, and the rising time of the linear vibration motor can be stabilized.

  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 shaft 8 is fixed to the frame 2 and the other end side is slidably supported by a bearing 9 fixed to the mover 10, but the other configuration is the same as the above-described example. is there.

  One end side of the shaft 8 is supported by the frame 2 at two points in the illustrated example. Specifically, the end portion of the 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 shaft 8.

  The mover 10 is provided with a hole 7C into which the free end side (the other end side) of the shaft 8 is inserted along a uniaxial direction (X direction in the drawing). A bearing 9 in which the shaft 8 is slidable in the X direction is provided in the hole 7C, whereby the other end of the shaft 8 is slidably supported by the bearing 9 fixed to the mover 10. Yes. 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. In this way, the shaft 8 is cantilevered with respect to the frame 2, and the magnet 4 is disposed on the extension 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 only necessary to form a hole 7 </ b> C corresponding to the passage of the shaft 8 therein, so that the volume of the weight portion 7 is sufficiently large. can do. Thereby, it is possible to sufficiently secure the mass of the mover 10 that becomes the inertial force of vibration.

  Also in such a linear vibration motor 1, as shown in FIG. 3, the shaft support 9B of the bearing 9 is formed of a hard magnetic material (permanent magnet), and the shaft 8 is formed of a soft magnetic material. In addition, the sliding characteristics of the mover 10 that slides relative to the shaft 8 become stable, and the rise time of the linear vibration motor can be stabilized.

  As described above, the linear vibration motor 1 according to the embodiment of the present invention can obtain a stable vibration by causing the movable element 10 to be supported by the shaft 8 and vibrate it, and is resistant to damage during a drop impact. Can increase the sex. Then, the shaft support 9B of the bearing 9 is made of a hard magnetic material, and the shaft 8 is made of a soft magnetic material, whereby linear vibration with a stable rise time can be obtained. In the above description, the shaft support 9B is a hard magnetic material and the shaft 8 is a soft magnetic material. However, the shaft support 9B may be a soft magnetic material and the shaft 8 may be a hard magnetic material.

  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. It can be transmitted to the user with stable vibration. In particular, since the rise time of vibration can be stabilized, signal generation can be transmitted to the user crisply, and skin sensation feedback can be realized with good responsiveness.

  Moreover, since the linear vibration motor 1 shown in the embodiment has a compact shape in which each part is accommodated in a rectangular parallelepiped frame 2 with a reduced thickness, the space is efficiently provided inside the thinned portable information terminal 100. Can be equipped. 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, 3: coil, 4: magnet part,
4A, 4B, 4C: Magnet piece, 4D, 4E: Spacer,
5: Reinforcing member, 6: Elastic member,
7: weight part, 7A: end, 7A1: support protrusion, 7B: shaft support part, 7C: hole,
8: shaft, 9: bearing, 10: mover,
11: connecting member, 100: portable information terminal

Claims (4)

A frame,
A mover that includes a magnet part and a weight part, and is elastically supported by the frame body so as to vibrate along a uniaxial direction;
A coil fixed to the frame and reciprocatingly vibrating the mover in a uniaxial direction by energization of a drive signal;
A shaft that guides the vibration of the mover along a uniaxial direction;
A bearing that slidably supports the shaft;
One of the shaft support body and the shaft included in the bearing is a hard magnetic body, and the other is a soft magnetic body.   The linear vibration motor according to claim 1, wherein the shaft is fixed to the mover, and the bearing is fixed to the frame.   The linear vibration motor according to claim 1, wherein the shaft is fixed to the frame body, and the bearing is fixed to the mover.   The portable electronic device provided with the linear vibration motor described in any one of Claims 1-3.

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