JP2016101546A - Vibration actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the elastic restoration force of a twist elastic member effectively act regardless of rotating directions, and to obtain large rotation amplitude with good balance, when reciprocating rotary vibrations are carried out.SOLUTION: A vibration actuator 1 includes: a rotary shaft 11 rotatably supported to a pair of bearings 12 and 13; a magnet 2 which is fixed to the rotary shaft 11, and has a different magnetic pole around the rotary shaft 11; a weight 3 fixed to the rotary shaft 11; a housing 30 which supports the bearings 12 and 13; a twist elastic member 4 fixed between the housing 30 and the rotary shaft 11 while twisting at an initial twisting angle; a coil 5 to which alternating current is supplied; and a magnetic pole member 6 which has magnetic pole pieces 60A and 60B disposed around the magnet 2 and magnetized to the magnetic poles different from each other by the alternating current supplied to the coil 5. By the magnetic repulsion force between the magnet 2 and the magnetic pole member 6 and the elastic restoration force of the twist elastic member 4, the rotary shaft 11 is reciprocatively rotated and vibrated.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 passed through 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.

  On the other hand, it is possible to avoid contact between the mover and the housing by vibrating the mover back and forth. At this time, if an attempt is made to obtain the elastic restoring force of the reciprocating rotational vibration using the torsion coil spring, the torsion coil spring can obtain an effective elastic restoring force for twisting in one direction from a state where the torsion angle is zero. There is a characteristic that an effective elastic restoring force cannot be obtained with respect to twisting in the other direction from a state where the twist angle is zero. As a result, when performing reciprocating rotational vibration, there is a problem that the elastic restoring force becomes unbalanced depending on whether the rotational direction is normal or reversed, and a well-balanced large rotational amplitude cannot be obtained.

  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, while taking advantage of the LRA without a contact commutator in order to obtain high reliability and durability, in principle, by obtaining a reciprocating rotational vibration that does not cause a collision between the mover and the housing, it is possible to reduce the size. Providing a vibration actuator capable of obtaining a larger vibration amplitude, and effectively performing the elastic restoring force of the torsional elastic member regardless of whether the rotational direction is normal or not when performing reciprocating rotational vibration, providing a large rotational amplitude with good balance It is an object of the present invention.

In order to achieve such an object, the vibration actuator according to 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 a torsion elastic member fixed between the casing and the rotating shaft in a state of being twisted at an initial twist angle, a coil to which an alternating current is supplied, and a coil disposed around the magnet and supplied to the coil A magnetic pole member having a plurality of magnetic pole pieces magnetized to different magnetic poles by an alternating current, and the rotating shaft by a magnetic repulsive force between the magnet and the magnetic pole member and an elastic restoring force of the torsion elastic member A vibration actuator characterized by reciprocally rotating and vibrating.

  The vibration actuator having such characteristics can provide a vibration actuator that is smaller and can obtain a larger vibration amplitude. When performing reciprocating rotational vibration, the elastic restoring force of the torsional elastic member is reversed in the forward and reverse directions. Regardless of this, it is possible to obtain an effective rotation amplitude with good balance.

1 is an external perspective view showing an overall configuration of a vibration actuator according to an embodiment of the present invention. It is sectional drawing of the vibration actuator which concerns on embodiment of this invention. It is explanatory drawing which showed the operation | movement of the drive part in the vibration actuator which concerns on embodiment of this invention, and the change of the twist state of a torsion elastic member ((a) is a non-energized state, (b) is the direction of the electric current which flows into a coil. In the case of +, (c) is the case where the direction of current flowing in the coil is-). It is sectional drawing of the vibration actuator which concerns on other embodiment of this invention. It is sectional drawing 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 movable weight 3 includes a weight 3, a torsion elastic member (torsion coil spring) 4 that gives an elastic restoring force to the driving rotation of the rotating shaft 11, and an intermediate position support member 19 that connects the rotating shaft 11 and the torsion elastic member 4. A child 10 is provided.

  In the illustrated example, the magnet 2, the torsion 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. The magnet 2 and the torsional elastic member 4 are disposed between the pair of bearings 12 and 13, but the weight 3 is fixed to the rotary shaft 11 protruding outside the pair of bearings 12 and 13.

The torsion coil spring as the torsion elastic member 4 has one end fixed to the bearing support member 14 or the frame body 16 via the end support member 17 in the state twisted at the initial twist angle θ ₀ , and the other end to the end support member 18. Is fixed to the frame body 16 or the magnetic pole piece 60A. The rotating shaft 11 is fixed to an intermediate position between both ends of the torsion elastic member 4 via an intermediate position support member 19. This torsion elastic member 4 may be divided into two torsion elastic members from one end to the intermediate position and from the intermediate position to the other end.

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. An alternating current having a frequency equivalent to the resonance frequency of the mover 10 is supplied to the coil 5 from an alternating current generating source 21 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 in the twist direction of the torsion elastic member 4, and f ₀ = (1 / 2π) · (k / J) It can be calculated by ^1/2 .

  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 is arranged in a magnetic circuit formed by the magnetic pole member (claw pole) 6. A different magnetic pole is induced in the magnetic pole pieces 60A and 60B by passing a current through the magnetic pole pieces 60A and 60B. Thus, 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 along the rotating shaft 11 is possible.

  The bearings 12 and 13 that support the rotary shaft 11 are fixed to bearing support members 14 and 15, respectively. The bearing support member 14 is fixed to the magnetic pole pieces 60 </ b> A and 60 </ b> B via the frame 16 by welding or the like. Is fixed to the magnetic pole piece 60A. Here, the bearing support members 14 and 15, the frame body 16, and the magnetic pole pieces 60 </ b> A and 60 </ b> B form the housing portion 30 that supports the bearings 12 and 13 or the torsion elastic member 4.

  A housing space for the magnet 2 and the torsion 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 directly or indirectly 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. .

The above-described twisted elastic member 4 is fixed between the casing 30 and the rotating shaft 11 in a state of being twisted at the initial twist angle θ _{0. In} the above-described example, both ends of the twisted elastic member 4 are the casing unit. The intermediate positions of both ends of the torsion elastic member 4 are fixed to the rotating shaft 11, but both ends of the torsion elastic member 4 are fixed to either the housing portion 30 or the rotating shaft 11, and both ends thereof are fixed. The intermediate position may be fixed to either the casing 30 or the rotating shaft 11.

  FIG. 3 shows the operation of the drive unit 20 of the vibration actuator 1 and the change in the twisted state of the torsion elastic member 4. (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 due to the reversal of the polarity in the magnetic pole pieces 60A and 60B, and rotational torques in different directions alternately act on the mover 10 (rotating shaft 11).

When rotational torque acts on the rotating shaft 11, twisting is applied to the torsion elastic member (torsion coil spring) 4, and the elastic restoring force of the torsion elastic member 4 acts on the rotating shaft 11. Here, the torsional elastic member 4 whose both ends are fixed to the housing part 30 is fixed in a state where one end A and the other end B thereof are twisted by the initial twist angle θ ₀ in the non-energized state shown in FIG. ing. Therefore, the intermediate position C between the one end A and the other end B of the torsion elastic member 4 is twisted by (1/2) θ ₀ from one end A to the intermediate position C, and further from the intermediate position C to the other end B ( 1/2) Twisted by θ ₀ .

With respect to such a twisted state of the torsion elastic member 4 when no current is supplied, when a positive current flows through the coil 5 as shown in (b) and the rotating shaft 11 rotates in one direction by a one-side deflection angle θ. The torsional elastic member 4 is twisted by (1/2) θ ₀ + θ from one end A to the intermediate position C, and twisted by (1/2) θ ₀ −θ from the intermediate position C to the other end B. It becomes a state. Further, as shown in (c), when a negative current flows through the coil 5 and the rotating shaft 11 rotates in the other direction by the one-side deflection angle θ, the torsional elastic member 4 extends from one end A to the intermediate position C ( 1/2) θ ₀ −θ is twisted, and the intermediate position C to the other end B is twisted by (½) θ ₀ + θ.

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 twist 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 a range of direction twist. As a result, when the movable element 10 is reciprocatingly oscillated, the elastic restoring force of the torsional elastic member 4 can be effectively applied regardless of whether the rotational direction is normal or reverse, and a well-balanced large rotational amplitude can be obtained. it can.

  4 and 5 show another configuration example of the vibration actuator 1 according to the embodiment of the present invention, in which the above-described torsional elastic member 4 is divided into two at an intermediate position. The same parts as those in the above-described embodiment are denoted by the same reference numerals, and redundant description is omitted.

  In the example shown in FIG. 4, the torsion elastic member 4 is divided into two torsion elastic members 4 </ b> A and 4 </ b> B, and both the torsion elastic members 4 </ b> A and 4 </ b> B are arranged inside the housing unit 30. One end side of the torsion elastic member 4A is fixed to the casing 30 (bearing support member 14) via an end support member 17A, and the other end side (intermediate position) is a rotation shaft via the end support member 18A. 11 or the magnet 2. Further, one end side of the torsion elastic member 4B is fixed to the casing 30 (the magnetic pole pieces 60A and 60B) via the end support member 17B, and the other end side (intermediate position) is connected via the end support member 18B. The rotary shaft 11 or the magnet 2 is fixed.

  In the example shown in FIG. 5 as well, the torsion elastic member 4 is divided into two torsion elastic members 4C and 4D, and in this example, the torsion elastic member 4C is provided in the housing portion 30 to provide the torsion elasticity. The member 4 </ b> D is disposed outside the housing unit 30. Then, one end side (intermediate position) of the torsion elastic member 4C is fixed to the housing portion 30 (bearing support member 14) via the end support member 17C, and the other end side is connected via the end support member 18C. It is fixed to the rotating shaft 11 or the magnet 2. Further, one end side of the torsional elastic member 4C is fixed to the weight 3 (rotating shaft 11), and the other end side (intermediate position) is connected to the housing portion 30 (bearing support member 14) via the end support member 18D. It is fixed.

In these examples as well, the two torsion elastic members 4A, 4B or 4C, 4D are fixed between the casing 30 and the rotating shaft 11 in a state of being twisted at the initial twist angle. Specifically, the two torsion elastic members 4A, 4B or 4C, 4D are fixed in a state where they are respectively twisted by the initial torsion angle 1 / 2θ ₀ , and the two torsion elastic members 4A, 4B or 4C, 4D are initially twisted. The angle ½θ ₀ is taken as the initial twist angle θ ₀ . Also in this manner, as in the above-described example, the torsion elastic member 4 is always effectively restored 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 rotary shaft 11 (movable element 10) can be oscillated in a reciprocating manner within a range of twisting in one direction that can exert a force.

  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, since the initial twist angle θ ₀ is given to the torsion elastic member 4 and is fixed between the housing portion 30 and the rotating shaft 11, the reciprocating vibration of the movable element 10 (the rotating shaft 11) is generated. The torsional elastic member 4 can be rotated within a range of one-way twisting, whereby the movable element 10 can be reciprocatingly oscillated with good forward / backward balance.

  FIG. 6 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, the vibration actuator 1 has high reliability and durability. In principle, the vibration actuator 1 does not cause a collision between the movable element 10 and the housing unit 30. It is possible to suppress the generation of abnormal noise and obtain a larger vibration amplitude with a smaller size. 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: Torsion 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, 16: frame body,
17, 17A, 17B, 17C, 18, 18A, 18B, 18C, 18D: end support member, 19: intermediate position support member,
20: drive unit, 21: alternating current generation source, 30: housing unit,
P: axis

Claims (8)

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;
A torsion elastic member fixed between the casing and the rotating shaft in a state of being twisted at an initial twist angle;
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;
A vibration actuator characterized in that 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 torsion elastic member.   Both ends of the torsional elastic member are fixed to either the housing part or the rotating shaft, and an intermediate position of the both ends is fixed to either the housing part or the rotating shaft. The vibration actuator according to claim 1.   The vibration actuator according to claim 2, wherein the torsional elastic member is divided into two at the intermediate position.   The coil, the magnet, and the weight are arranged side by side along the rotation axis, and the weight is fixed to the rotation shaft protruding from one of the pair of bearings. The vibration actuator according to any one of claims.   5. The vibration actuator according to claim 1, wherein the housing portion is provided integrally with the magnetic pole piece or connected to the magnetic pole piece.   6. The vibration actuator according to claim 1, wherein the alternating current has a frequency equivalent to a resonance frequency of a mover that reciprocally rotates and vibrates with the magnet. 7. The vibration actuator according to claim 1, wherein the initial twist angle θ ₀ is set to be larger than twice the one-side swing angle θ in the reciprocating rotational vibration of the rotating shaft.   A portable electronic device comprising the vibration actuator according to claim 1.

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