Vibration Actuator

Abstract

To obtain a vibration actuator which prevents shifting of an axis of a movable body and enables reduction of a gap between a magnet and a yoke.SOLUTION: A vibration actuator 1 includes a movable element 30 that forms a magnetic drive unit together with a coil 24 provided in a cylindrical case 10 and vibrates along an axial direction of the case 10 while being supported by the case 10 via a leaf spring 2. The movable element 30 is formed, including a magnet 34 and a yoke 32. The yoke 32 is provided at a central portion of the movable element 30.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to vibration actuators. [Background technology]

[0002] Patent Document 1 discloses a vibration actuator in which a yoke and a coil are fixed to the inner periphery of a cylindrical case to form a case-side drive unit (stator), and a mover made up of a magnet, pole pieces, and a mass is elastically supported by the case. In this vibration actuator, AC power is passed through the coil to generate magnetic repulsion and magnetic attraction between the coil and the magnetic circuit of the mover, causing the mover to vibrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. WO2020 / 175610 Summary of the Invention [Problem to be solved by the invention]

[0004] In order to increase the thrust of the mover, it is desirable to reduce the gap between the magnet and the yoke.

[0005] On the other hand, the magnetic force of the magnet acts between the magnet and the yoke in a direction that attracts them to each other. Therefore, when the position of the magnet is displaced with respect to the yoke that constitutes the stator, as in Patent Document 1, if the gap between the magnet and the yoke is too small, the magnet may be attracted to the yoke by the magnetic force, causing the axis of the mover to become misaligned.

[0006] In consideration of the above, the present disclosure aims to provide a vibration actuator that can prevent the axis of the mover from shifting and reduce the gap between the magnet and the yoke. [Means for solving the problem]

[0007] A vibration actuator according to a first aspect of the present disclosure comprises a cylindrical case, a coil provided in the case, elastic members provided at one and the other axial ends of the case, and a mover including a magnet and a yoke, which together with the coil constitutes a magnetic drive unit, and which vibrates along the axial direction of the case while being supported by the case via the elastic members, wherein the yoke is provided at the center of the mover.

[0008] The vibration actuator according to the first aspect includes a mover that constitutes a magnetic drive unit together with a coil provided in a cylindrical case and that vibrates along the axial direction of the case while being supported by the case via an elastic member. This mover includes a magnet and a yoke, and the yoke is provided at the center of the mover and vibrates integrally with the magnet. Therefore, the position of the magnet does not shift relative to the yoke. As a result, the axial center of the mover is prevented from shifting due to the magnetic force of the magnet, and the gap between the magnet and the yoke can be reduced.

[0009] A vibration actuator according to a second aspect of the present disclosure is the mover described in the first aspect, wherein the magnets are arranged at intervals in the vibration direction, and include a first magnet arranged on one side of the yoke in the vibration direction and a second magnet arranged on the other side of the yoke in the vibration direction.

[0010] In the vibration actuator according to the second aspect, the magnet is composed of a first magnet arranged on one side of the yoke in the vibration direction and a second magnet arranged on the other side, and by disposing a part of the yoke between the two magnets arranged with a gap in the vibration direction, the magnet is connected through the yoke at the center of the vibration direction of the magnet. This makes it possible to easily connect the magnet and yoke without requiring a complex structure for passing the yoke through the center of the vibration direction of the magnet.

[0011] A vibration actuator according to a third aspect of the present disclosure is such that, in the mover configured as described in the second aspect, the magnetization directions of the first magnet and the second magnet are the same along the vibration direction.

[0012] In the vibration actuator according to the third aspect, the magnetization directions of the first magnet and the second magnet are the same in the axial direction, so a strong magnetic attraction force acts between the first magnet and the second magnet across the yoke that passes through the center. This makes it possible to firmly connect the magnet and the yoke using the magnetic attraction force, making it easy to ensure the adhesive strength between the components.

[0013] A vibration actuator according to a fourth aspect of the present disclosure is a mover according to any one of the first to third aspects, wherein the yoke has a center portion passing through the center of the vibration direction of the magnet and side portions extending from the outer edge of the center portion to one side and the other side of the vibration direction and covering the outer periphery of the magnet.

[0014] In a vibration actuator according to a fourth aspect, the yoke has side portions extending to one side of the center of the yoke in the vibration direction, covering the outer periphery of the magnet. This allows two magnetic gaps to be formed on both sides of the center of the yoke in the vibration direction, separated by the center of the yoke. Conventional vibration actuators have a structure in which two coils are spaced apart in the vibration direction, each placed in two magnetic gaps within the case. However, these typically form a magnetic gap by placing one magnet at the center of the vibration direction, making it difficult to adjust the position of the magnetic gap while taking into account the vibration mass. In contrast, a configuration in which two magnetic gaps can be formed on both sides of the center of the yoke in the vibration direction, separated by the center of the yoke, allows the vibration mass and the position of the magnetic gap to be easily adjusted by changing the plate thickness of the center of the yoke.

[0015] A vibration actuator according to a fifth aspect of the present disclosure is configured as any one of the fourth aspects, wherein the movable element further comprises a pole piece arranged on the outside of the magnet in the vibration direction, and the coil is arranged between the pole piece and the yoke on the outer periphery of the magnet, and has a first region arranged in a magnetic gap formed between the pole piece and the yoke, and a second region exposed from the magnetic gap in the vibration direction.

[0016] In a vibration actuator according to a fifth aspect, a pole piece is disposed outside the magnet in the vibration direction, and a coil is disposed in a magnetic gap formed between the pole piece and the yoke. Here, the coil has a first region disposed within the magnetic gap and a second region exposed from the magnetic gap in the vibration direction. This ensures that the coil region disposed within the magnetic gap is secured in a vibration state in which the mover displaces relative to the coil, thereby stabilizing the magnetic flux passing through the coil. Furthermore, the same structure can be used to accommodate larger displacements of the mover due to an increase in vibration mass.

[0017] A vibration actuator according to a sixth aspect of the present disclosure has the configuration described in the fifth aspect, and further comprises a cylindrical bobbin provided in the case and covering the outer periphery of the pole piece, and the coil is wound around the outer periphery of the bobbin.

[0018] In a vibration actuator according to a sixth aspect, the outer periphery of the pole piece is covered by a cylindrical bobbin provided in the case, and a coil is wound around the outer periphery of the bobbin. That is, the bobbin is disposed between the pole piece constituting the mover and the coil constituting the stator. This ensures insulation between the pole piece and the bobbin even when a strong external impact is applied to the case.

[0019] A vibration actuator according to a seventh aspect of the present disclosure is configured as any one of the first to sixth aspects, wherein the mover is supported by the elastic member via a connecting member arranged along the axial center of the case.

[0020] In the vibration actuator according to the seventh aspect, the mover that vibrates in the axial direction of the case is supported by elastic members provided at one end and the other end of the axial direction of the case via connecting members, which eliminates the need to give the mover a complex shape for joining to the elastic members provided on the case side, thereby reducing the cost of the component.

[0021] A vibration actuator according to an eighth aspect of the present disclosure is configured as described in the seventh aspect, wherein the case has a cylindrical extension portion arranged with a gap between it and its inner circumference, and the connecting member is arranged inside the extension portion with its outermost portion positioned closely facing the inner circumference of the extension portion.

[0022] In a vibration actuator according to an eighth aspect, the case has a cylindrical extension portion arranged with a gap between it and the inner periphery, and the connecting member is arranged inside the extension portion. Here, since the outermost periphery of the connecting member is arranged closely facing the extension portion, even when a strong external impact is applied to the case, the outermost periphery of the connecting member can abut against the extension portion, preventing the movable part from contacting the coil.

[0023] A vibration actuator according to a ninth aspect of the present disclosure has the configuration described in the seventh or eighth aspect, in which the tip end of the connecting member is inserted into a through hole formed through the elastic member and is joined to the elastic member in a crushed and crimped state.

[0024] In the vibration actuator according to the ninth aspect, the connecting member is joined to the elastic member by crushing and crimping the tip end portion, which means that no additional parts such as joining screws are required to join the connecting member and the elastic member, thereby reducing the cost of parts.

[0025] A vibration actuator according to a tenth aspect of the present disclosure is configured as described in any one of the first to ninth aspects, wherein in the movable member, the magnet and the yoke are joined via an adhesive, and a recess recessed in the bonding direction is formed on at least one of the opposing bonding surfaces, the recess extending along the outer periphery of the bonding surface and configured to be able to accommodate a portion of the adhesive.

[0026] In a vibration actuator according to a tenth aspect, the magnet and yoke that constitute the mover are bonded together via an adhesive. Here, a recess recessed in the bonding direction is formed on at least one of the opposing bonding surfaces of the magnet and yoke. This recess extends along the outer periphery of the bonding surface and is configured to be able to accommodate a portion of the adhesive. As a result, when the magnet and yoke are bonded together, some of the excess adhesive is pushed outward and accommodated in the recess. As a result, the excess adhesive leaking out of the bonding surface can be prevented from interfering with the adhesive and the coil.

[0027] A vibration actuator according to an eleventh aspect of the present disclosure comprises a cylindrical case, a coil provided in the case, elastic members provided at one and the other axial ends of the case, a magnet and a yoke, which together with the coil form a magnetic drive unit, and a movable element which vibrates along the axial direction of the case while being supported by the case via the elastic member, the magnet having a first magnet and a second magnet arranged at a distance in the vibration direction, and the yoke being joined to the first magnet and the second magnet in the vibration direction so that a portion of the yoke is sandwiched between the first magnet and the second magnet.

[0028] A vibration actuator according to an eleventh aspect includes a mover that, together with a coil provided in a cylindrical case, constitutes a magnetic drive unit and is supported by the case via an elastic member and vibrates along the axial direction of the case. The mover includes a magnet and a yoke, and the magnet has a first magnet and a second magnet that are spaced apart in the vibration direction. The yoke is joined to the first magnet and the second magnet in the vibration direction such that a portion of the yoke is sandwiched between the first magnet and the second magnet. This prevents the magnet from displacing relative to the yoke because the yoke constitutes part of the mover and vibrates integrally with the magnet. As a result, the axial center of the mover is prevented from being misaligned due to the magnetic force of the magnet, and the gap between the magnet and the yoke can be reduced. [Effects of the Invention]

[0029] As described above, the vibration actuator according to the present disclosure has the excellent effect of preventing the axis of the mover from shifting and reducing the gap between the magnet and the yoke. [Brief explanation of the drawings]

[0030] [Figure 1] 1 is a partially cross-sectional perspective view of a vibration actuator according to an embodiment of the present invention, showing a portion thereof cut along the center line of the case in the axial direction. [Figure 2] FIG. 2 is an exploded perspective view of the mover according to the embodiment. [Figure 3] 1 is a cross-sectional view of a vibration actuator according to an embodiment of the present invention, taken along the center line of the case in the axial direction. [Figure 4] 5A to 5C are schematic diagrams illustrating the operation of the vibration actuator according to the present embodiment. [Figure 5] 4 is a cross-sectional view corresponding to FIG. 3, showing an example of a use example of the vibration actuator according to the present embodiment. FIG. [Figure 6] FIG. 10 is a diagram showing the relationship between frequency and displacement of the vibration actuator according to the example. [Figure 7]FIG. 10 is a diagram showing the relationship between frequency and acceleration of the vibration actuator according to the example. [Figure 8] FIG. 10 is a diagram showing the relationship between frequency and excitation force of the vibration actuator according to the example. [Figure 9] FIG. 4 is a cross-sectional view corresponding to FIG. 3, showing a first modified example of the vibration actuator of the present embodiment. [Figure 10] 10 is a cross-sectional view corresponding to FIG. 3, showing a second modified example of the vibration actuator of the present embodiment. FIG. [Figure 11] FIG. 4 is a cross-sectional view corresponding to FIG. 3, showing a third modified example of the vibration actuator of the present embodiment. [Figure 12] 10 is a cross-sectional view corresponding to FIG. 3, showing a fourth modified example of the vibration actuator of the present embodiment. FIG. [Figure 13] FIG. 10 is a cross-sectional view corresponding to FIG. 3, showing a fifth modified example of the vibration actuator of the present embodiment. [Figure 14] FIG. 10 is a cross-sectional view corresponding to FIG. 3, showing a sixth modified example of the vibration actuator of the present embodiment. [Figure 15] 10 is a schematic diagram corresponding to FIG. 4, showing the magnetization direction of the magnet, of a seventh modified example of the vibration actuator of the present embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0031] A vibration actuator 1 according to this embodiment will now be described with reference to Figures 1 to 5. Note that a line segment O shown as appropriate in each of Figures 1 to 4 indicates the center line of the vibration actuator 1 in the vibration direction (axial direction).

[0032] As shown in Figures 1 to 3, vibration actuator 1 of this embodiment is made up of members of the same shape, with a symmetry plane S (see Figure 3) perpendicular to center line O at a point halfway along the vibration direction (the center of the vibration direction) as the boundary. Therefore, with regard to the configuration of each member, only one side of the symmetrical configuration will be described, and the other will be given the same reference numerals unless otherwise necessary, and a description thereof will be omitted. Furthermore, when referring to the "center of the mover," it refers to the center side of the mover in the vibration direction, and the inward and outward directions with center line O as the axis will be expressed as the inner periphery or outer periphery based on center line O.

[0033] The vibration actuator 1 mainly comprises a cylindrical case 10 forming the outer shell, a stator 20 provided inside the case 10, a mover 30 that can vibrate due to the stator 20, and leaf springs 2 that elastically support both ends of the mover 30 in the vibration axis direction relative to the case 10.

[0034] The case 10 comprises a cylindrical case body 12 whose axial direction is the vibration direction of the vibration actuator 1, a cover case (not shown) that closes both end openings, and a coil frame 14 provided on the inner periphery near the opening of the case body 12. In this embodiment, the case body 12, the cover case, and the coil frame 14 are each made of a resin material such as ABS, but are not limited to resin materials. In addition, terminals (not shown) to which lead wires are connected are formed on the outer surface of the case body 12.

[0035] The coil frame 14 has an annular frame portion 14A provided along the opening of the case body 12. This frame portion 14A has multiple boss portions 16 protruding from the inner periphery. In this embodiment, three boss portions 16 are provided at equal intervals along the circumferential direction of the frame portion 14A. The outer periphery of the leaf spring 2 is disposed above the frame portion 14A, and the leaf spring 2 is fixed to the coil frame 14 using pins 18 that are crimped to the boss portions 16. The case body 12 and the frame portion 14A of the coil frame 14 may be joined by screws, adhesive, or welding.

[0036] Furthermore, the coil frame 14 has an extension portion 14C formed inside the frame portion 14A via a step portion 14B. The extension portion 14C has a generally cylindrical shape extending from the inner edge of the step portion 14B toward the center in the vibration direction, and has an outer diameter smaller than that of the frame portion 14A. The extension portion 14C is disposed radially inward with a gap provided from the inner circumferential surface of the case body 12, and supports the stator 20 on the outer circumferential side facing the inner periphery of the case body 12.

[0037] The vibration actuator 1 comprises an electromagnetic drive unit that is made up of a stator 20 provided inside a case 10 and a mover 30 that can be vibrated by the stator 20 .

[0038] The stator 20 has a bobbin 22 made of paper and a coil 24 fixed to the bobbin 22. The bobbin 22 is fixed to the outer periphery of the extension portion 14C of the coil frame 14 using an adhesive, and has a generally cylindrical shape extending from the extension portion 14C toward the center in the vibration direction. The coil 24 is wound around the outer periphery of the bobbin 22 and fixed to the bobbin 22 using an adhesive.

[0039] The coil 24 is disposed within the case 10 with a gap provided between it and the inner periphery of the case body 12. The coil 24 is also disposed in a magnetic gap G between the yoke 32 and the pole piece 36, which will be described later. To prevent contact between the coil 24 and the pole piece 36 during vibration, the bobbin 22 is supported by the coil frame 14 so as to cover the surface (outer periphery) of the pole piece 36, with a gap provided between the inner periphery of the bobbin 22 and the outer periphery of the pole piece 36. The lead wires of the coil 24 are connected to terminals (not shown) on the outer surface side of the case body 12, and a magnetic field can be generated by applying current from the terminals.

[0040] The mover 30 is disposed within the case body 12 so as to vibrate along the direction of the center line O, which is the axial direction of the cylindrical case 10. The mover 30 includes a yoke 32, a magnet 34, a pole piece 36, and a connecting member 40. The magnet 34, the pole piece 36, and the connecting member 40 are disposed in this order from the center of the vibration direction toward the outside inside the case body 12. In this embodiment, the yoke 32 and the pole piece 36 are formed of a soft magnetic metallic material, and the connecting member 40 is formed of a resin material such as ABS.

[0041] The yoke 32 is formed in a cylindrical shape with a bottom that opens outward in the vibration direction, and includes a center portion 321 and a side portion 322. The center portion 321 is disk-shaped and is disposed at the center of the case body 12 in the vibration direction. The side portion 322 is cylindrical and extends from the outer edge of the center portion 321 outward in the vibration direction. This yoke 32 is integrated with the other yoke 32 that is disposed symmetrically with respect to a symmetry plane S that is perpendicular to the center line O direction (vibration direction) by bonding their centers 321 together. In other words, by integrating the two yokes 32 that are disposed on one side and the other side of the center of the case body 12 in the vibration direction, a yoke 32 whose cross section along the vibration direction is approximately H-shaped is disposed inside the case body 12.

[0042] The magnet 34 is substantially disk-shaped and is disposed outside the center 321 of the yoke 32 in the vibration direction. Furthermore, a disk-shaped pole piece 36 is disposed outside the magnet 34 in the vibration direction. The side portion 322 of the yoke 32 described above covers the outer periphery of the magnet 34 and the pole piece 36, and a gap is provided between the outer periphery of the magnet 34 and the pole piece 36 and the inner periphery of the side portion 322. The coil 24 of the stator 20 is disposed in the magnetic gap G formed between the pole piece 36 and the yoke 32.

[0043] Here, coil 24 has a region (first region) that is located within magnetic gap G and a region (second region) that is exposed in the vibration direction from magnetic gap G. Therefore, in a vibration state in which mover 30 moves relative to coil 24, the region of the coil that is located within magnetic gap G can be secured, and the magnetic flux that passes through coil 24 can be stabilized.

[0044] The magnetic gap G here refers to the area where the outer periphery of the pole piece 36 and the inner periphery of the side portion 322 of the yoke 32 face each other.

[0045] As shown in FIG. 3 , the pole piece 36 is connected to the center of the leaf spring 2 via a connecting member 40. The connecting member 40 is cylindrical with its axial direction aligned with the vibration direction and is disposed along the axial center of the case body 12. The openings at both ends of the connecting member 40 are disposed coaxially with through holes 361 and 21 formed through the axial centers of the pole piece 36 and the leaf spring 2. The pole piece 36 and the connecting member 40 are fixed together by inserting a first fixing pin 42 into the through hole 361 of the pole piece 36 and the opening of the connecting member 40 from the center side in the vibration direction. The connecting member 40 and the leaf spring 2 are fixed together by inserting a second fixing pin 44 into the through hole 21 of the leaf spring 2 and the opening of the connecting member 40 from the outside in the vibration direction. As a result, the mover 30, which is composed of the yoke 32, magnet 34, and pole piece 36, is elastically supported by the case 10 via the leaf spring 2.

[0046] The following describes the symmetrical internal configuration of the vibration actuator 1. For ease of understanding, the mover 30 disposed on one side of the center of the vibration direction of the case 10 will be referred to as the first mover 30A, and the yoke 32, magnet 34, and pole piece 36 constituting the first mover 30A will be referred to as the yoke 32A, first magnet 34A, and first pole piece 36A, respectively. The mover 30 disposed on the other side of the center of the vibration direction of the case 10 will be referred to as the second mover 30B, and the yoke 32, magnet 34, and pole piece 36 constituting the second mover 30B will be referred to as the second yoke 32B, second magnet 34B, and second pole piece 36B, respectively. The coil 24 disposed in the magnetic gap G of the first mover 30A will be referred to as the first coil 24A, and the coil 24 disposed in the magnetic gap G of the second mover 30B will be referred to as the second coil 24B, respectively.

[0047] The vibration actuator 1 of this embodiment has a first mover 30A arranged on one side of the case 10 in the vibration direction and a second mover 30B arranged on the other side. The first mover 30A and the second mover 30B are arranged symmetrically with respect to a plane of symmetry S perpendicular to the vibration direction, so that the first magnet 34A of the first mover 30A and the second magnet 34B of the second mover 30B are arranged with a gap in the vibration direction. The centers 321 of the yoke 32A and the second yoke 32B are sandwiched between the first magnet 34A and the second magnet 34B and joined to the first magnet 34A and the second magnet 34B in the vibration direction. That is, the yokes (yoke 32A, second yoke 32B) of this embodiment are arranged so that a portion thereof passes through the center of the magnet 34 (first magnet 34A, second magnet 34B) in the vibration direction. As a result, the first magnet 34A and the second magnet 34B that constitute the magnetic drive unit are configured to vibrate without their relative positional relationship with the yoke 32A and the second yoke 32B being displaced.

[0048] Here, the magnetization directions of the first magnet 34A and the second magnet 34B are the same along the vibration direction. Therefore, as shown by the arrows in Fig. 4, in the first mover 30A and the second mover 30B of this embodiment, the magnetic field lines of the second magnet 34B pass through the center 321 of the yoke 32A and the second yoke 32B to reach the first magnet 34A, forming a magnetic circuit that passes through the magnetic gap G, the side portion 322 of the yoke 32A, the side portion 322 of the second yoke 32B, and the magnetic gap G. Therefore, the components arranged along the vibration direction are strongly connected by magnetic attraction.

[0049] In this embodiment, since no repulsive magnetic field is generated between the first mover 30A and the second mover 30B, the first mover 30A and the second mover 30B can be magnetized after assembly.

[0050] 3, the vibration actuator 1 has a first leaf spring 2A attached to one axial end of the case 10 and a second leaf spring 2B attached to the other end. The first mover 30A and the second mover 30B are supported by the first leaf spring 2A and the second leaf spring 2B, respectively, via a connecting member 40 arranged along the axial center (center line O) of the case 10.

[0051] The connecting member 40 may be made of a lightweight resin material such as ABS, or may be made of a relatively heavy non-magnetic material such as metal or resin, and configured as a mass for adjusting the load mass between the first and second movable elements 30A, 30B and the first and second leaf springs 2A, 2B.

[0052] The first leaf spring 2A and the second leaf spring 2B are each made of one or more metal leaf springs; for example, in this embodiment, they are made of processed thin stainless steel plates. The material of the first leaf spring 2A and the second leaf spring 2B is not limited to metal, but may be a composite material containing resin or fiber. Furthermore, the material of the first leaf spring 2A and the second leaf spring 2B may be any material that is highly durable and flexible, such as a coil spring. The first leaf spring 2A and the second leaf spring 2B correspond to the "elastic member" in this disclosure.

[0053] Each of the first leaf spring 2A and the second leaf spring 2B has three arms 23 that extend spirally from the center toward the periphery, and the outer ends of each arm 23 are connected to and supported by the frame portion 14A of the coil frame 14 and the boss portion 16 of the case body 12.

[0054] In this embodiment, the first leaf spring 2A and the second leaf spring 2B are arranged symmetrically with respect to the plane of symmetry S. The spiral directions of the arms 23 of these two leaf springs are opposite to each other. As a result, when the vibration actuator 1 vibrates, the first movable element 30A and the second movable element 30B receive torque in opposite directions from the first leaf spring 2A and the second leaf spring 2B, respectively, and therefore do not rotate around the axis along the center line O even when vibrating in the vibration direction.

[0055] The first leaf spring 2A and second leaf spring 2B configured in this manner are elastically deformable within a predetermined range in the vibration direction (direction of center line O) and in the plane of symmetry S perpendicular to the vibration direction. This predetermined range corresponds to the amplitude range of the first mover 30A and second mover 30B when used normally as the vibration actuator 1. Therefore, the predetermined range is at least a range in which the first leaf spring 2A and second leaf spring 2B do not come into contact with the case 10, and a range in which the limits of elastic deformation of the first leaf spring 2A and second leaf spring 2B are not exceeded.

[0056] (Action and effect)

[0057] In the vibration actuator 1 configured as described above, when no current is applied to the first and second coils 24A, 24B, the first and second movers 30A, 30B are positioned in the center of the first and second coils 24A, 24B, as shown in FIG. 3.

[0058] When vibrating the first and second movers 30A and 30B, AC power is passed through terminals (not shown) provided on the outer surface of the case 10 in a direction that generates magnetic fields of alternately opposite polarities in the first and second coils 24A and 24B. In other words, the same polarity is generated in adjacent portions of the first and second coils 24B.

[0059] For example, in the case of the polarity shown in Figure 4, a thrust force is generated in the first and second movers 30A, 30B toward the other side of the vibration direction indicated by solid arrow A (downward in Figure 4), and if the current flowing through the first and second coils 24A, 24B is reversed, a thrust force is generated in the first and second movers 30A, 30B toward one side of the vibration direction indicated by dotted arrow B (upward in Figure 4).

[0060] In this way, when AC power is applied to the first and second coils 24A, 24B, the first and second movable elements 30A, 30B vibrate along the center line O while receiving the biasing forces from the first and second leaf springs 2A, 2B on both sides.

[0061] The thrust generated in the first and second movers 30A, 30B basically conforms to the thrust provided based on Fleming's left-hand rule. In this embodiment, because the first and second coils 24A, 24B are fixed to the case 10, a thrust is generated in the first and second movers 30A, 30B to which the first and second magnets 34A, 34B are attached as a reaction force to the force generated in the first and second coils 24A, 24B. Therefore, the horizontal component of the magnetic flux of the first and second magnets 34A, 34B (the component in the plane of symmetry S) contributes to the thrust. Furthermore, because the first and second yokes 32A, 32B increase the horizontal component of the magnetic flux of the first and second magnets 34A, 34B, a mutually attractive magnetic force acts between the first and second magnets 34A, 34B and the first and second yokes 32A, 32B.

[0062] Therefore, if the first and second yokes 32A, 32B constitute a stator fixed to the case 10, if the gap between the first and second magnets 34A, 34B and the first and second yokes 32A, 32B becomes too small, the mutually attractive magnetic forces may cause the axis of the mover 30 to become misaligned. This makes it difficult to reduce the gap between the first and second magnets 34A, 34B and the first and second yokes 32A, 32B in order to increase the thrust of the first and second movers 30A, 30B.

[0063] In contrast, according to this embodiment, a portion of the yoke 32, which is made up of the first and second yokes 32A and 32B, passes through the center of the vibration direction of the magnet 34, which is made up of the first and second magnets 34A and 34B, and is joined to the magnet 34 in the vibration direction. Therefore, the yoke 32 constitutes a part of the mover 30 and vibrates integrally with the magnet 34, so the position of the magnet 34 does not shift relative to the yoke 32. As a result, the axis of the mover 30 is prevented from shifting due to the magnetic force of the magnet 34, and the gap between the magnet 34 and the yoke 32 can be reduced.

[0064] Furthermore, according to this embodiment, the magnet 34 is composed of a first magnet 34A arranged on one side of the center 321 of the yoke 32 in the vibration direction and a second magnet 34B arranged on the other side, and by disposing a part of the yoke between the two magnets arranged with a gap in the vibration direction, the magnet 34 is connected to the center of the vibration direction through the yoke 32. This makes it possible to easily connect the magnet 34 and the yoke 32 without requiring a complex structure for passing the yoke through the center of the vibration direction of the magnet 34.

[0065] Furthermore, according to this embodiment, the magnetization directions of the first magnet 34A and the second magnet 34B are the same in the axial direction, so a strong magnetic attraction force acts between the first magnet 34A and the second magnet 34B across the center portion 321 of the yoke 32, which passes through the center. This makes it possible to firmly connect the magnet 34 and the yoke 32 using the magnetic attraction force, and easily ensure the adhesive strength between the members.

[0066] Furthermore, according to this embodiment, the yoke 32A and the second yoke 32B are connected and integrated to form a single yoke 32 having an H-shaped cross section along the vibration direction. Therefore, the side portions 322 extend to one side and the other side of the center 321 of the yoke 32, which passes through the center of the magnet 34 in the vibration direction, and cover the outer periphery of the magnet 34. This allows two magnetic gaps G to be formed on both sides of the center 321 of the yoke 32 in the vibration direction. Conventional vibration actuators have a structure in which two coils are spaced apart in the vibration direction and each coil is placed in two magnetic gaps within a case. However, these actuators typically form a magnetic gap by placing one magnet at the center of the vibration direction, making it difficult to adjust the position of the magnetic gap in consideration of the vibration mass. In contrast, a configuration in which two magnetic gaps G can be formed on both sides of the center 321 of the yoke 32 in the vibration direction can easily adjust the vibration mass and the position of the magnetic gap G by changing the plate thickness of the center 321 of the yoke 32.

[0067] Furthermore, in this embodiment, the pole piece 36 is disposed on the outside of the magnet 34 in the vibration direction, and the coil 24 is disposed in the magnetic gap G formed between the pole piece 36 and the yoke 32. Here, the coil 24 has a first region disposed within the magnetic gap G and a second region exposed from the magnetic gap G in the vibration direction. This ensures that the region of the coil 24 disposed within the magnetic gap G is secured in a vibration state in which the mover 30 displaces relative to the coil 24, and the magnetic flux passing through the coil 24 can be stabilized. Furthermore, even if the displacement of the mover 30 increases due to an increase in the vibration mass, the same structure can be used to accommodate this.

[0068] Furthermore, according to this embodiment, the outer periphery of the pole piece 36 is covered by a cylindrical bobbin 22 provided in the case 10, and the coil 24 is wound around the outer periphery of the bobbin 22. That is, the bobbin 22 is disposed between the pole piece 36 constituting the mover 30 and the coil 24 constituting the stator 20. This ensures insulation between the pole piece 36 and the bobbin 22 even when a strong external impact is applied to the case 10.

[0069] Furthermore, in this embodiment, the mover 30, which vibrates in the axial direction of the case 10, is elastically supported by the first leaf spring 2A and the second leaf spring 2B, which are provided at one end and the other end of the axial direction of the case 10, via the connecting member 40, without any mass in between. As a result, the vibration actuator 1 does not require a mass with a complex shape that takes weight and balance characteristics into consideration, which allows for reductions in component costs.

[0070] In this embodiment, the mover 30 is composed of a first mover 30A having a yoke 32A, a first magnet 34A, and a first pole piece 36A, and a second mover 30B having a second yoke 32B, a second magnet 34B, and a second pole piece 36B. The first mover 30A and the second mover 30B are joined together so that the yoke 32A and the second yoke 32B face each other at the center of the vibration direction of the case 10, forming a symmetrical structure in the vibration direction. This allows the first mover 30A and the second mover 30B to share common functional components, reducing component costs and facilitating assembly.

[0071] Furthermore, the vibration actuator 1 of this embodiment can be implemented in a variety of applications. For example, it can be used to vibrate devices such as mobile phones, smartphones, and other portable devices, game console controllers, beauty devices including facial massagers and massagers, and diaphragm pumps. The amplitude (displacement) of the first and second leaf springs 2A and 2B according to this embodiment can be increased by changing the hardness of these leaf springs to make them more susceptible to elastic deformation. For this reason, as shown in an example in FIG. 5, by fixing the tip of the connecting member 50 connecting the first armature 30A and the first leaf spring 2A to a diaphragm 70 made of an elastic material, the actuator can be used as an actuator for reciprocating the diaphragm 70.

[0072] In the example shown in Figure 5, the tip of the connecting member 50 is connected to the center of a diaphragm 70 fixed to a housing 60. A suction opening 62 is formed on the upper surface of the housing 60 facing the diaphragm 70, and when the diaphragm 70 is displaced to the other side in the vibration direction (downward in Figure 5) due to operation of the vibration actuator 1, external air is sucked in through the opening 62 in the housing 60. In this way, the vibration actuator 1 of this embodiment can also be used for sucking gas. Note that in Figure 5, some reference numerals have been omitted to make the drawing easier to understand.

[0073] Regarding the connecting member 50, the connecting member 50 is composed of a first connecting member 52 and a second connecting member 54 arranged along the axial center of the case 10. The first connecting member 52 is cylindrical with its axial direction aligned with the vibration direction and is arranged between the first armature 30A and the first leaf spring 2A. The end of the first connecting member 52 on the center side in the vibration direction is mechanically joined to the first pole piece 36A using a first fixing pin 42, similar to the connecting member 40 of the above embodiment. The end of the first connecting member 52 on the outer side in the vibration direction is formed with a protrusion 521 that is inserted into the through hole 21 of the first leaf spring 2A and protrudes outward in the vibration direction. The second connecting member 54 is cylindrical with its axial direction aligned with the vibration direction and has a recess 541 formed at the end on the center side in the vibration direction that corresponds to the protrusion 521 of the first connecting member 52. The first connecting member 52 and the second connecting member 54 are fixed in a state in which the protruding portion 521 is inserted into the recessed portion 541 so as to sandwich the first leaf spring 2A.

[0074] [Example] To confirm the effects of the present invention for different actuator applications, the inventors investigated the relationships between frequency (Hz) and displacement (mm), frequency (Hz) and acceleration (m / s), and frequency (Hz) and excitation force (N) for a conventional vibration actuator (e.g., the vibration actuator described in International Publication WO 2020 / 175610) that has a stator with a single magnet positioned at the center of the vibration direction and a yoke fixed to the case, a vibration actuator 1 corresponding to FIGS. 1 to 3 designed for vibration applications, and a vibration actuator 1 corresponding to FIG. 5 designed for suction applications. The results are shown in FIGS. 6 to 8.

[0075] In each of Figures 6 to 8, a conventional vibration actuator is shown by a solid line, a vibration actuator 1 designed for vibration applications is shown by a dashed line, and a vibration actuator 1 designed for suction applications is shown by a dotted line.

[0076] In each example, the input power was set to 1 W, and the two coils that make up the stator were configured to have the same performance. Furthermore, the connecting member 40 in the above-described embodiment, which was made of a resin material, was changed to a configuration made of a soft magnetic metal material, and the connecting member 40 was configured as a mass with a load mass of 100 g. Furthermore, in the vibration actuator 1 for vibration and the vibration actuator 1 for attraction, the vibration mass (the sum of the masses of the yoke, magnet, pole piece, and mass) was set larger and the magnetic gap G was set smaller compared to the conventional example.

[0077] The only difference in configuration between the vibration actuator 1 for vibration and the vibration actuator 1 for suction is the mechanical compliance value (expressed as the reciprocal of the spring constant) of the first and second leaf springs 2A, 2B. The mechanical compliance value of the vibration actuator 1 for vibration is set to 0.50 [mm / N], while that of the vibration actuator for suction is set to 1.25 [mm / N].

[0078] As shown in Figure 6, in the suction vibration actuator 1 indicated by the dashed line, the mechanical compliance values ​​of the first and second leaf springs 2A, 2B are set larger than those for vibration, and soft springs are used, so it can be seen that the displacement amount exceeds that of the conventional example and the vibration actuator in the low frequency band below 40 Hz.

[0079] As shown in FIG. 7, the vibration actuator 1 for vibration indicated by the broken line has a larger vibration mass and a higher peak acceleration value than the conventional example.

[0080] As shown in FIG. 8, even though the mass load due to the mass is the same for the vibration actuator 1 shown by the dashed line and the conventional example shown by the solid line, the vibration mass, including the mass of the yoke, magnet, and pole piece, of the vibration actuator 1 exceeds that of the conventional example, and therefore the magnitude of the excitation force exceeds that of the conventional example.

[0081] [supplementary explanation] The vibration actuator 1 of this embodiment has been described above, but the configuration of each part can be changed or combined without departing from the spirit of the invention. Furthermore, the present disclosure is not limited to the above embodiment, and configurations according to the various modifications shown in FIGS. 9 to 11 may also be applied. Note that each of the modifications shown in FIGS. 9 to 11 basically follows the configuration of the vibration actuator 1 according to the above embodiment, except for some modified components. Therefore, to make the drawings easier to understand, some reference numerals have been omitted in the drawings.

[0082] (First Modification) In the above embodiment, the first magnet 34A and the second magnet 34B directly sandwich the center 321 of the first and second yokes 32A and 32B. However, the present disclosure is not limited to this. As shown in FIG. 9 , a first modified example of a mover 80 (80A, 80B) may be used in which the center 321 of the first and second yokes 32A and 32B is sandwiched between the first magnet 34A and the second magnet 34B via a member. In this first modified example, a disk-shaped intermediate pole piece 82 made of a soft magnetic metal material is disposed between the center 321 of the first and second yokes 32A and 32B and the first and second magnets 34A and 34B. In this configuration, the position of the mover 80 along the vibration direction can be adjusted using a soft magnetic material with a simple shape, such as the intermediate pole piece 82, making it easy to adjust the height of the magnetic gap relative to the coil 24. Furthermore, by providing the intermediate pole piece 82, the distance between the tip of the stator 20 and the center 321 of the first and second yokes 32A, 32B can be secured, so that the movable member 80 can vibrate at a position where the coil 24 does not interfere with the first and second yokes 32A, 32B.

[0083] (Second Modification) In the above embodiment, the yoke 32A and the second yoke 32B are formed in a cylindrical shape with a bottom, and the central portion 321 of each is integrated to form a yoke having an H-shaped cross section. However, the present disclosure is not limited to this. The yoke 32A and the second yoke 32B may be integrally formed to form a single component. That is, as in the mover 90 according to a second modified example shown in FIG. 10 , side portions 96 extending to one and the other sides in the vibration direction may be integrally formed on the outer edge of a disk-shaped central portion 94 disposed at the center of the vibration direction within the case 10, thereby forming a yoke 92 having an H-shaped cross section in the vibration direction.

[0084] Furthermore, in the above embodiment, the first and second pole pieces 36A, 36B and the connecting member 40 are configured as separate members, but this is not limiting, and the pole pieces and the connecting member may be integrally formed, as in the pole piece 100 according to the second modified example. In the pole piece 100 according to the second modified example, a cylindrical connecting portion 104 standing along the axial center of the case 10 is integrally formed with a disk-shaped main body 102. The connecting portion 104 is connected to the first and second leaf springs 2A, 2B by inserting a second fixing pin 44 into a recess 104 formed at the tip of the connecting portion 104.

[0085] (Third Modification) Furthermore, in the above embodiment, the connecting member 40 connecting the mover 30 and the leaf spring 2 is formed in an elongated cylindrical shape, but the present disclosure is not limited to this. In this third modified example, the connecting member 110 includes a cylindrical connecting portion 112, a bottom portion 114 extending radially from the end of the connecting portion 112 that is closer to the center in the vibration direction, and a cylindrical outer peripheral wall portion 116 extending outward in the vibration direction from the outer edge of the bottom portion 114. The outer peripheral wall portion 116, which forms the outermost periphery of the connecting member 110, is disposed adjacent to and opposite the extending portion 14C of the coil frame 14. Therefore, even when an external impact or the like is applied to the vibration actuator 1, the outer peripheral wall portion 116 of the connecting member 110 abuts against the extending portion 14C of the coil frame 14, thereby preventing contact between the mover 30 and the coil 24. In this case, the size of the gap between the outer wall portion 116 of the connecting member 110 and the extension portion 14C can be set smaller than the size of the gap between the side portion 322 of the yoke 32 that constitutes the movable member 30 and the coil 24, thereby reliably preventing contact between the movable member 30 and the coil 24.

[0086] (Fourth Modification) 5 described the configuration of the suction vibration actuator 1 fixed to the diaphragm 70 using the connecting member 50. With this configuration, the vibration actuator 1 can be configured as an actuator for a diaphragm pump 120, as shown in FIG. 12. The diaphragm 70 is fixed to the bottom surface of a housing 122 of the diaphragm pump 120, and the volume of the internal chamber C can be changed by deformation (vibration) of the diaphragm 70. The housing 122 is formed with a first flow path 124 and a second flow path 126 that communicate with the chamber C. A suction valve 130 is attached to the first flow path 124. As shown in FIG. 12(A), when the diaphragm 70 is displaced in a direction that increases the volume of the chamber C, the suction valve 130 opens, entering an intake cycle. Furthermore, a discharge valve 140 is attached to the second flow path 126. As shown in FIG. 12(B), when the diaphragm 70 is displaced in a direction that reduces the volume of the chamber C, the discharge valve 140 opens, entering a discharge cycle.

[0087] (Fifth Modification) In the above embodiment, the mover 30 (30A, 30B) and the connecting member 40, and the connecting member 40 and the leaf spring 2 (2A, 2B) are joined via the first and second fixing pins 42, 44, respectively, but the present disclosure is not limited to this. As shown in Fig. 13, they may be joined without using fixing pins or screws.

[0088] 13, the connecting member 250 and the pole piece 240 of the mover 210 (210A, 210B) are fixed together using an adhesive 260. The connecting member 250 and the leaf spring 2 are joined by inserting the tip 250A of the connecting member 250 into a through-hole 21 formed through the axial center of the leaf spring 2, and by being crushed and crimped to the leaf spring 2. This eliminates the need for additional parts such as screws for joining the connecting member 250 and the leaf spring 2, as well as the mover 210, thereby reducing the cost of parts.

[0089] Furthermore, in this vibration actuator 200, the case body 302, coil frame 304, and coil frame 304 and cover case 306 that make up the case 300 are joined together using an adhesive (not shown). And, because the yoke 220, magnet 230, and pole piece 240 that make up the mover 210 are joined together using adhesive 260, the vibration actuator 200 can be assembled without using screws or pins for joining.

[0090] Here, the yoke 220 of the mover 210 has a cross section along the vibration direction (direction of the center line O) of the mover that is substantially E-shaped. This yoke 220 is integrally formed with a disk-shaped central portion 221 that forms the bottom, a cylindrical side portion 222 that stands upright from the outer edge of the central portion 221, and a cylindrical center pillar portion 223 that stands upright from the central portion 221 inside the side portion 222. That is, the yoke 220 according to the fifth modification corresponds to the configuration in which the yoke 32 (32A, 32B) and the intermediate pole piece 82 of the first modification shown in FIG. 9 are integrally formed. Therefore, since it basically follows the configuration of the mover 80 (80A, 80B) according to the first modification, it achieves the same effects. Furthermore, by integrally forming a member corresponding to the intermediate pole piece 82 with the yoke 220, the number of parts can be reduced.

[0091] Furthermore, in the yoke 220 and the pole piece 240 of the fifth modified example, a recess 270 recessed in the bonding direction is formed on the bonding surface facing the magnet 230. The recess 270 extends along the outer periphery of the bonding surface and is formed in a ring shape in this embodiment. When the magnet 230 and the yoke 220, and the magnet 230 and the pole piece 240 are bonded together, a portion of the excess adhesive 260 is pushed out toward the outer periphery of the bonding surface and accommodated in the recess 270. This prevents the excess adhesive from leaking outside the bonding surface, eliminating the risk of interference between the excess adhesive and the coil. This allows the magnetic gap G of the mover 210 to be set small.

[0092] In the fifth modification, recess 270 is formed on the adhesive surfaces of yoke 220 and pole piece 240, but this is not limiting. Recess 270 may be provided on at least one of the adhesive surfaces of yoke 220, magnet 230, and pole piece 240 that face each other, and recess 270 may also be provided on the adhesive surface of magnet 230.

[0093] (Sixth Modification) In the fifth modified example, the center pillar portion 223 is provided on the yoke 220 to adjust the position of the mover 80 along the vibration direction, but this is not limiting. As in the sixth modified example shown in FIG. 14 , the position of the mover 80 may be adjusted by disposing a plate-shaped spacer 280 between two yokes 220 spaced apart along the vibration direction. The spacer 280 may be formed of a non-magnetic material that does not constitute a magnetic circuit, or may be formed of a soft magnetic material and form part of the magnetic circuit together with the yoke 220. The sixth modified example has the same configuration as the fifth modified example except for disposing the plate-shaped spacer 280 between the two yokes 220, and therefore a detailed description thereof will be omitted. In FIG. 14 , some reference numerals are omitted for clarity.

[0094] (Seventh Modification) In the above embodiment, the magnetization directions of the first magnet 34A and the second magnet 34B are set in the same direction along the vibration direction, but the present disclosure is not limited to this. As in the seventh modified example shown in FIG. 15, the magnetization directions of the first magnet 34A and the second magnet 34B may be set in opposite directions along the vibration direction. In this case, as shown by the arrows in FIG. 15, the first magnet 34A forms a magnetic circuit that passes through the yoke 32A via the first pole piece 36A and magnetic gap G. The second magnet 34B also forms a magnetic circuit that passes through the second yoke 32B via the second pole piece 36B and magnetic gap G.

[0095] In the above magnetic circuit, the second magnet 34B acts as a repulsive magnet for the first magnet 34A, thereby suppressing magnetic leakage. Although a repulsive magnetic field is generated between the first yoke 32A and the second yoke 32B, ensuring the thickness of the center portion 321 ensures the mechanical strength when the first yoke 32A and the second yoke 32B are joined. Furthermore, the first mover 30A and the second mover 30B can be assembled by joining them using an adhesive or the like after the first magnet 34A and the second magnet 34B have been magnetized in advance.

[0096] In the above embodiments and modifications, the dimensions and shapes of the yoke, magnet, and pole piece are configured to be the same for the first mover 30A and the second mover 30B, but this is not essential. In other words, it is not essential to arrange the movers 30 of the magnetic drive unit in a symmetrical structure with respect to the center of the vibration direction, and for example, the first magnet 34A and the second magnet 34B may be configured to be different sizes.

[0097] In addition, in this embodiment, the first yoke 32A and the second yoke 32B are arranged inside the case 10, but the present disclosure is not limited to this. That is, as long as at least one yoke is provided in the center of the mover and is joined to the magnet in the vibration direction, the second yoke 32B, the second pole piece 36B, and the second coil 24B may be omitted from inside the case 10.

[0098] In the above embodiment and each modified example, the coil 24 is configured to have a region (first region) that is located within the magnetic gap G and a region (second region) that is exposed from the magnetic gap G in the vibration direction, but the present disclosure is not limited to this. The axial length of the wound coil may be set short so that the entire coil is located within the magnetic gap G. Even in this configuration, setting the coil length short allows the entire coil to be located within the magnetic gap G even during vibration of the mover, thereby stabilizing the magnetic flux passing through the coil and reducing changes in the magnetic force that the coil receives. [Explanation of symbols]

[0099] 1. Vibration Actuator 2 Elastic member (first leaf spring 2A, second leaf spring 2B) 10 cases 14C Extension 24 coils 34 Magnet (first magnet 34A, second magnet 34B) 32 York (32A, 32B) 321 Center 322 Side 36 pole pieces (36A, 36B) 30 Mover (30A, 30B) 21 through hole (through hole formed through elastic member) 22 Bobbin 40 Connecting member 50 Connecting member 80 Mover (80A, 80B) 110 Connecting member 116 Outer wall portion (outermost portion) 200 Vibration Actuator 210 Mover (200A, 200B) 250 connecting members 250A tip 260 Adhesive 270 recess 300 cases G Magnetic gap

Claims

1. A cylindrical case and a coil provided in the case; elastic members provided at one end and the other end of the case in the axial direction; a mover including a magnet and a yoke, which constitutes a magnetic drive unit together with the coil, and which is supported by the case via the elastic member and vibrates along the axial direction of the case; the movable element includes a pole piece disposed on the outer side of the magnet in the vibration direction, In the mover, the yoke is provided at the center of the mover, The coil is disposed between the pole piece and the yoke on the outer circumferential side of the magnet, and has a first region disposed in a magnetic gap formed between the pole piece and the yoke, and a second region exposed from the magnetic gap in the vibration direction. Vibration actuator.

2. 2. The vibration actuator according to claim 1, wherein the magnets in the movable element are arranged at intervals in the vibration direction, and the movable element has a first magnet arranged on one side of the vibration direction of the yoke and a second magnet arranged on the other side of the vibration direction of the yoke.

3. 3. The vibration actuator according to claim 2, wherein in the mover, the magnetization directions of the first magnet and the second magnet are aligned in the same direction along the vibration direction.

4. A vibration actuator according to any one of claims 1 to 3, wherein the yoke in the movable element has side portions that extend to one side and the other side of the center of the movable element and cover the outer periphery of the magnet.

5. a cylindrical bobbin provided in the case and covering an outer periphery of the pole piece; The vibration actuator according to claim 1 , wherein the coil is wound around the outer periphery of the bobbin.

6. 6. The vibration actuator according to claim 1, wherein the movable element is supported by the elastic member via a connecting member disposed along the axial center of the case.

7. the case has a cylindrical extension portion disposed with a gap between itself and an inner periphery thereof, 7. The vibration actuator according to claim 6, wherein the connecting member is disposed inside the extending portion, with the outermost periphery of the connecting member disposed closely facing the inner periphery of the extending portion.

8. 8. The vibration actuator according to claim 6, wherein a tip end of the connecting member is inserted into a through hole formed through the elastic member, and is joined to the elastic member in a crushed and crimped state.

9. In the mover, the magnet and the yoke are bonded to each other via an adhesive, and a recess recessed in the bonding direction is formed on at least one of the bonding surfaces facing each other, 9. The vibration actuator according to claim 1, wherein the recess extends along the outer periphery of the adhesive surface and is configured to be able to accommodate a portion of the adhesive.

10. A cylindrical case and a coil provided in the case; elastic members provided at one end and the other end of the case in the axial direction; a mover including a magnet and a yoke, which constitutes a magnetic drive unit together with the coil, and which is supported by the case via the elastic member and vibrates along the axial direction of the case; the movable element includes a pole piece disposed on the outer side of the magnet in the vibration direction, The magnet includes a first magnet and a second magnet that are spaced apart in the vibration direction, the yoke is joined to the first magnet and the second magnet in a vibration direction such that a portion of the yoke is sandwiched between the first magnet and the second magnet, The coil is disposed between the pole piece and the yoke on the outer circumferential side of the magnet, and has a first region disposed in a magnetic gap formed between the pole piece and the yoke, and a second region exposed from the magnetic gap in the vibration direction. Vibration actuator.

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