JP2016103881A - Vibration actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin vibration actuator which can meet requirement for thinning and in which a weight is vibrated with a great driving force.SOLUTION: A vibration actuator 1 comprises: a rotary shaft 11 which is journaled by bearings 12 and 13 in a freely rotatable manner; a magnet 2 which is fixed to the rotary shaft 11 and has different magnetic poles around the rotary shaft 11; a weight 3 which is fixed to the rotary shaft 11; a housing part 30 which supports the bearings 12 and 13; an elastic member 4 which applies an elastic restoration force to driving rotation of the rotary shaft 11; a coil 5 to which an alternating current is supplied; and a magnetic pole member 6 including a plurality of magnetic pole pieces 60A and 60B which are disposed around the magnet 2 and magnetized at magnetic poles different from each other by the alternating current supplied to the coil 5. The magnetic pole member 6 includes a core 62 around which the coil 5 is wound outside of the rotary shaft 11 and reciprocally and rotationally vibrates the rotary shaft 11 with a magnetic repulsive force of the magnet 2 and the magnetic pole member 6 and the elastic restoration force of the elastic member 4.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a vibration actuator that performs reciprocating rotational vibration.

  Vibrating actuators generate vibrations by receiving incoming communications equipment or sending alarms from various electronic devices, etc., and communicating the signal input status by vibration to operators who touch communication equipment carriers and various electronic devices. It is equipped in various electronic devices such as portable information terminals including mobile phones.

  As a vibration actuator, a linear resonance actuator (LRA) is known (see Patent Document 1 below). In the LRA, an alternating current equal to the natural frequency of a weight suspended by a spring is applied to the winding to cause the weight to reciprocate linearly in a linear direction by interaction with the magnet. As another type of vibration actuator, there is also known a DC motor type (ERM: Eccentric Rotating Mass) (see Patent Document 2 below) in which an eccentric weight is attached to a shaft to obtain vibration around the shaft. Since LRA does not have a contact commutator like ERM, LRA has high reliability and durability, and is suitable for applications with high operation frequency that also serves as haptics for touch panels in addition to incoming alarms.

JP 2012-016153 A JP 2006-224068 A

  Since the vibration value of the LRA is determined by the mass of the mover and its vibration amplitude, when trying to obtain the maximum vibration value in a limited space for incorporation in a portable electronic device, the maximum range of the internal space dimension of the housing is reached. The vibration amplitude is set, and the contact between the mover and the housing is inevitable. When the mover and the housing come into contact with each other, a collision sound at that time and a chatter sound due to the collision are generated, and the original purpose of the vibration actuator provided to transmit the signal generation to the user without sound is reduced. Problems that cannot be achieved.

  For this, a cushioning material that softens the generated sound is generally provided between the mover and the housing, but the generated sound cannot be completely eliminated and can be an essential solution. Absent. Further, when trying to avoid contact in terms of structure, the amplitude of the mover is reduced with respect to the internal space of the casing, or the casing is increased with respect to the amplitude of the mover, which is smaller and larger. The request to obtain vibration amplitude cannot be satisfied.

  In addition, portable electronic devices are increasingly required to be thin, such as support for wearable devices. On the other hand, since the conventional LRA is based on a structure in which a coil is wound around a magnet that is a part of a mover, a thin thickness necessary for incorporation in a thinner portable electronic device is obtained. Had structural limitations.

  This invention makes it an example of a subject to cope with such a problem. In other words, by taking advantage of the LRA that does not have a contact commutator in order to obtain high reliability and durability, in principle, a mechanism that does not cause a collision between the mover and the housing can be made smaller and larger. Providing a vibration actuator capable of obtaining vibration amplitude, providing a thin vibration actuator capable of meeting the demand for higher thickness reduction, and obtaining effective reciprocating rotational vibration by vibrating the weight with a larger driving force This is the object of the present invention.

In order to achieve such an object, the present invention has the following configuration.
A rotating shaft rotatably supported by a bearing, a magnet fixed to the rotating shaft and having different magnetic poles around the rotating shaft, a weight fixed to the rotating shaft, and a housing portion that supports the bearing And an elastic member for applying an elastic restoring force to the driving rotation of the rotating shaft, a coil to which an alternating current is supplied, and magnetic poles that are arranged around the magnet and are different from each other according to the alternating current supplied to the coil. A magnetic pole member having a plurality of magnetic pole pieces to be magnetized, the magnetic pole member having a core around which the coil is wound around the outer side of the rotating shaft, and a magnetic repulsive force between the magnet and the magnetic pole member; A vibration actuator that reciprocally vibrates the rotating shaft by an elastic restoring force of the elastic member.

  Smaller and larger vibration amplitude can be obtained, and a thin vibration actuator that can meet the demand for higher thickness can be provided. In addition, effective reciprocating rotational vibration can be achieved by vibrating the weight with a large driving force. Can be obtained.

It is the disassembled perspective view which showed the whole structure of the vibration actuator which concerns on one Embodiment of this invention. It is sectional drawing which showed the whole structure of the vibration actuator which concerns on one Embodiment of this invention. It is explanatory drawing which showed operation | movement of the drive part in the vibration actuator which concerns on embodiment of this invention ((a) is a non-energized state, (b) is the case where the direction of the electric current which flows into a coil is +, (c) is a coil. When the direction of the current flowing through is-. It is sectional drawing which showed the whole structure of the vibration actuator which concerns on other embodiment of this invention. It is explanatory drawing which showed the portable electronic device provided with the vibration actuator which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIGS. 1 and 2, the vibration actuator 1 is fixed to the rotating shaft 11, the rotating shaft 11 that is rotatably supported by the pair of bearings 12, 13, the magnet 2 fixed to the rotating shaft 11, and the rotating shaft 11. The mover 10 includes a weight 3, an elastic member (torsion coil spring) 4 that gives an elastic restoring force to driving rotation of the rotary shaft 11, and an end support member 18 that connects the rotary shaft 11 and the elastic member 4. It has.

  In the illustrated example, the magnet 2, the elastic member 4, and the weight 3 are arranged side by side along the rotation shaft 11 that is rotatably supported by the pair of bearings 12 and 13. Further, although the magnet 2 and the elastic member 4 are disposed between the pair of bearings 12 and 13, the weight 3 is fixed to the rotating shaft 11 protruding outside the pair of bearings 12 and 13.

  One end of the torsion coil spring as the elastic member 4 is fixed to the bearing support member 14 via the end support member 17, and the other end is fixed to the rotary shaft 11 or the magnet 2 via the end support member 18.

The drive unit 20 for reciprocatingly oscillating the mover 10 around the axis P that is the rotation center of the rotating shaft 11 includes the magnet 2, the coil 5, and the magnetic pole member 6 that are also part of the mover 10. The coil 5 is supplied with an alternating current having a frequency equivalent to the resonance frequency of the mover 10 from an alternating current generating source connected to the lead terminal 51. The resonance frequency of the mover 10 is a natural vibration frequency f ₀ determined by the inertia J of the mover 10 and the spring constant k of the elastic member 4 in the twist direction, and f ₀ = (1 / 2π) · (k / J) ¹ It can be calculated by ^{/ 2} . If such a natural vibration frequency f ₀ can be calculated, the elastic member 4 is not limited to the torsion coil spring but may be a mainspring spring, for example.

  The magnetic pole member 6 has a plurality of magnetic pole pieces 60 </ b> A and 60 </ b> B arranged around the magnet 2 and facing the magnetic poles of the magnet 2 having different magnetic poles around the rotating shaft 11. By changing the magnetic poles, rotational torques in different directions are alternately applied to the rotating shaft 11 to which the magnets 2 are fixed by the magnetic repulsive force between the magnets 2 and the magnetic pole members 6.

  The coil 5 is wound around the axis P by being wound around the coil holding member 50. The plurality of magnetic pole pieces 60 </ b> A and 60 </ b> B in the magnetic pole member 6 support the coil holding member 50 via the connecting portions 61 </ b> A and 61 </ b> B, respectively, and extend along the outside of the magnet 2. A core 62 constituting the magnetic pole member 6 is disposed at the core of the coil holding member 50, and both ends thereof are connected to the magnetic pole pieces 60A and 60B via connecting portions 61A and 61B, respectively.

  Here, the coil 5 is held by the coil holding member 50 at a position shifted in the axial direction from the fixed position of the magnet 2, and the core 62 around which the coil 5 is wound is provided outside the rotating shaft 11. By supplying an alternating current to the coil 5, different magnetic poles are induced in the magnetic pole pieces 60A and 60B. In this way, by shifting the position of the coil 5 in the axial direction with respect to the fixed position of the magnet 2, a structure in which the coil 5, the magnet 2, and the weight 3 are arranged in parallel along the rotation shaft 11 is possible.

  The bearings 12 and 13 that support the rotating shaft 11 are fixed to bearing support members 14 and 15, respectively. The bearing support member 14 is fixed to the magnetic pole pieces 60A and 60B by welding or the like, and the bearing support member 15 is fixed to the magnetic pole piece 60A. Has been. The bearing support members 14 and 15 and the magnetic pole pieces 60 </ b> A and 60 </ b> B here serve as a housing portion 30 that supports one end side of the bearings 12 and 13 or the elastic member 4.

  A housing space for the magnet 2 and the elastic member 4 is formed inside the housing portion 30, and a vibration space for the weight 3 is formed outside the housing portion 30. The weight 3 is an eccentric weight having a semicircular shape in plan view, and the vibration trajectory of the outer peripheral surface thereof is preferably the same as or outside the outer diameter of the housing portion 30. In the illustrated example, the bearing support members 14 and 15 are connected and fixed to the magnetic pole pieces 60A and 60B. However, the bearing support members 14 and 15 may be formed integrally with the magnetic pole pieces 60A and 60B.

  FIG. 3 shows the operation of the drive unit 20 of the vibration actuator 1. (A) is a non-energized state, (b) is the case where the direction of the current flowing through the coil is +, and (c) is the case where the direction of the current flowing through the coil is-. In the illustrated example, the cylindrical magnet 2 is magnetized in one pole in the diametrical direction and has different magnetic poles around the axis P. Not limited to this, the magnet 2 may be magnetized with a plurality of poles along the circumferential direction. On the other hand, a plurality of magnetic pole pieces 60 </ b> A and 60 </ b> B facing the magnetic pole of the magnet 2 are arranged close to each other along the outer periphery of the magnet 2. In the non-energized state shown in (a), the magnetic pole pieces 60A and 60B are not magnetized, but by passing a current through the coil 5, the magnetic pole pieces 60A and 60B are magnetized to different magnetic poles, and the coil 5 is alternated. By flowing the current, the polarities of the magnetic pole pieces 60A and 60B are reversed depending on whether the current direction is positive or negative, as shown in (b) and (c). The direction of the magnetic repulsive force acting on the magnet 2 is reversed by the reversal of the polarity of the magnetic pole pieces 60A and 60B, and the movable element 10 can be reciprocally rotated around the axis P.

  The vibration actuator 1 reciprocally vibrates the movable element 10 about the axis P, so that the vibration of the movable element 10 can be contained in a constant space even when the vibration amplitude varies by maximizing the vibration amplitude. I am doing so. In this way, it is possible in principle to prevent the mover 10 from coming into contact with the surrounding casing and generating a collision sound or chatter noise. The vibration actuator 1 supplies an alternating current having a frequency equivalent to the resonance frequency of the mover 10 to the drive unit 20 that reciprocally rotates and vibrates the mover 10 by alternately applying rotational torque in different directions to the magnet 2. And a magnetic pole member 6 that changes the magnetic pole by an alternating current flowing in the coil 5. As a result, high reliability and durability can be obtained as compared with a commutator having contacts such as ERM.

  And since the coil 5, the magnet 2, and the weight 3 are arranged in parallel along the rotating shaft 11 rotatably supported by a pair of bearings 12 and 13, compared with what winds the coil 5 around the magnet 2. Thus, the vibration actuator 1 can be thinned. Accordingly, it is possible to provide the vibration actuator 1 that can meet the demand for higher thickness reduction because it is built in a portable electronic device.

  Further, the core 62 of the magnetic pole member 6 around which the coil 5 is wound is provided outside the rotating shaft 11, and the inside of the coil 5 is enriched with the magnetic pole member 6. As a result, the volume capacity of the magnetic pole member 6 and the winding width of the coil 5 can be ensured without increasing the overall diameter of the casing 30, and the vibration actuator 1 can be made thin and with a large driving force. The weight 3 can be reciprocally rotated.

FIG. 4 shows a vibration actuator according to another embodiment of the present invention. The same parts as those in the above-described embodiment are denoted by the same reference numerals, and redundant description is omitted. In this embodiment, both ends of the elastic member 4 are fixed to the housing portion 30 via end support members 17 and 18, and an intermediate position between both ends of the elastic member 4 is a rotation shaft via an intermediate position support member 19. 11 is fixed. The elastic member 4 is fixed between the casing 30 and the rotating shaft 11 with one end and the other end being twisted at an initial twist angle θ ₀ in a non-energized state. In the example shown in FIG. 4, both ends of the elastic member 4 are fixed to the housing portion 30, and the intermediate positions of both ends of the elastic member 4 are fixed to the rotating shaft 11. 30 and the rotary shaft 11 may be fixed to each other, and the intermediate positions of both ends thereof may be fixed to either the housing 30 or the rotary shaft 11. Also in this case, the elastic member 4 is fixed in a state where one end and the other end thereof are not energized and are twisted by the initial twist angle θ ₀ .

Here, by setting the initial twist angle θ ₀ to be larger than twice the one-side swing angle θ in the reciprocating vibration of the rotating shaft 11, the elastic member 4 can always exhibit an effective elastic restoring force. The rotary shaft 11 (movable element 10) can be oscillated in a reciprocating manner within the torsional range. As a result, when the mover 10 is reciprocatingly oscillated, the elastic restoring force of the elastic member 4 can be effectively acted regardless of whether the rotational direction is normal or reverse, and a well-balanced large rotational amplitude can be obtained. .

  FIG. 5 shows a portable electronic device 100 including the vibration actuator 1. The portable electronic device 100 such as a mobile phone or a personal digital assistant has a high demand for thinning, and the vibration actuator 1 incorporated in the portable electronic device 100 has a large vibration amplitude while being small enough to cope with a limited installation space. What you have is required. Since the vibration actuator 1 does not have a contact commutator, it has high reliability and durability. In principle, the vibration actuator 1 does not cause a collision between the movable element 10 and the housing. The generation of sound can be suppressed, and a smaller and larger vibration amplitude can be obtained. Further, by shifting the positions of the magnet 2 and the coil 5 along the rotating shaft 11, it is possible to further reduce the thickness.

  The portable electronic device 100 including the vibration actuator 1 having such a feature can minimize the generation of sound and transmit a signal such as an incoming call or an alarm to the user by vibration and has a large vibration amplitude. Reliable signal transmission becomes possible. In addition, the portable electronic device 100 can be further reduced in thickness.

  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: Vibration actuator, 2: Magnet, 3: Weight
4, 4A, 4B, 4C, 4D: elastic member (torsion coil spring),
5: Coil, 50: Coil holding member, 51: Lead terminal,
6: Magnetic pole member, 60A, 60B: Magnetic pole piece,
61A, 61B: connecting portion, 62: core,
10: mover, 11: rotating shaft, 12, 13: bearing,
14, 15: bearing support member,
17, 18: end support member, 19: intermediate position support member,
20: Drive unit, 30: Housing unit,
P: axis

Claims (6)

A rotating shaft rotatably supported on the bearing;
A magnet fixed to the rotating shaft and having different magnetic poles around the rotating shaft;
A weight fixed to the rotating shaft;
A housing for supporting the bearing;
An elastic member for applying an elastic restoring force to the driving rotation of the rotating shaft;
A coil to which an alternating current is supplied;
A magnetic pole member having a plurality of magnetic pole pieces that are arranged around the magnet and magnetized to different magnetic poles by an alternating current supplied to the coil;
The magnetic pole member includes a core around which the coil is wound around the outer side of the rotary shaft, and the rotary shaft is reciprocally rotated by a magnetic repulsive force between the magnet and the magnetic pole member and an elastic restoring force of the elastic member. A vibration actuator characterized in that   2. The vibration according to claim 1, wherein the coil, the magnet, and the weight are arranged in parallel along the rotation shaft, and the weight is fixed to the rotation shaft protruding from one of the pair of bearings. Actuator.   The vibration actuator according to claim 1, wherein the casing is provided integrally with the magnetic pole piece or connected to the magnetic pole piece.   4. The vibration actuator according to claim 1, wherein the alternating current has a frequency equivalent to a resonance frequency of a mover that reciprocally vibrates together with the magnet. 5.   The vibration actuator according to any one of claims 1 to 4, wherein the elastic member is fixed in a state of being twisted at an initial twist angle between the housing portion and the rotation shaft.   A portable electronic device comprising the vibration actuator according to claim 1.

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