Vibration actuator and portable device

A vibration actuator includes: a fixing part including one of a coil and a magnet; a movable part including the other one of the coil and the magnet; and an elastic supporting part configured to support the movable part movably with respect to the fixing part. The movable part is configured to reciprocate with respect to the fixing part in a vibration direction through cooperation between the powered coil and the magnet. The magnet is disposed away from and radially inside the coil. The elastic supporting part has a plate-like shape in which one end of the elastic supporting part is fixed to the fixing part at the side of the movable part and the other end is fixed to the movable part, and cantilevers the movable part in such a manner that the movable part can reciprocate in the vibration direction.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is entitled to the benefit of Japanese Patent Application No. 2017-254218, filed on Dec. 28, 2017, the disclosure of which including the specification, drawings and abstract is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention relates to a vibration actuator and a portable device.

BACKGROUND ART

Conventionally, a vibration actuator has been mounted in a portable device as a vibration source for notifying an incoming call by transmitting vibrations to a finger, a limb, or the like, and for improving the operational feeling on a touch panel and the realism of an amusement machine such as a controller of a game machine. It should be noted that portable devices include wearable terminals attached to clothing, arms, and the like, in addition to portable communication terminals, such as mobile phones and smartphones, personal digital assistants, such as tablet PCs, portable game terminals, and controllers (game pads) of stationary game machines.

The vibration actuators disclosed in PTLs 1 to 3 include a fixing part having a coil and a movable part having a magnet, and cause the movable part to reciprocate by utilizing the driving force of a voice coil motor consisting of the coil and the magnet, thereby generating vibrations. These vibration actuators are linear actuators in which the movable part linearly moves along the shaft and are mounted in such a manner that the vibration direction is parallel to the main surface of a portable device. To the body surface of a user to be in contact with the portable device, vibrations in directions along the body surface are transmitted.

In the vibration motors disclosed in PTLs 4 and 5, the movable part has magnets vertically opposed with respect to the coil. The movable part is supported by a plate spring in which the main surface portion of the spring is parallel to the vertical direction, and vibrates in the lateral direction with the force generated between the coil and the magnet.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

A portable device having a vibrating function is required to be able to give a user sufficient physically-felt vibrations. However, the vibration actuators disclosed in PTLs 1 to 5, which generate the vibrations in directions along the body surface, have a problem that they cannot give sufficient physically-felt vibrations. Besides, the configurations of PTLs 4 and 5, in which the coil and the magnet are vertically opposed, have a problem that the coil and the magnet need to have predetermined vertical thicknesses to give the user sufficient physically-felt vibrations, which makes it impossible to reduce the vertical thicknesses. Moreover, these vibration actuators have a problem that when the spring for supporting the movable part is attached to the basal plate of the fixing part, process marks made by the attachment are left on the basal plate, which interferes with attaching the vibration actuator on the flat plane of the basal plate.

An object of the present invention is to provide a vibration actuator and a portable device in which high flatness of the basal plate is ensured without an increase in size and which can give the user sufficient physically-felt vibrations.

Solution to Problem

In order to achieve the above object, the present invention provides a vibration actuator, including:a fixing part including one of a coil and a magnet;a movable part including the other one of the coil and the magnet; andan elastic supporting part configured to support the movable part movably with respect to the fixing part, in whichthe movable part is configured to reciprocate with respect to the fixing part in a vibration direction through cooperation between the coil supplied with electric power and the magnet,the magnet is disposed away from and radially inside the coil, andthe elastic supporting part has a plate-like shape in which one end of the elastic supporting part is fixed to the fixing part at a side of the movable part and the other end is fixed to the movable part, and cantilevers the movable part in such a manner that the movable part can reciprocate in the vibration direction.

Advantageous Effects of Invention

The present invention can provide a vibration actuator and a portable device that can give sufficient physically-felt vibrations to the user while ensuring the flatness of the basal plate, without an increase in size.

DESCRIPTION OF EMBODIMENTS

[Overall Structure of Vibration Actuator1]

FIG. 1is a perspective view of an external appearance of vibration actuator1according to Embodiment 1 of the present invention.FIG. 2is a perspective view showing a state in which cover15of vibration actuator1is removed.FIG. 3is an exploded perspective view of vibration actuator1.FIG. 4is a longitudinal sectional view showing the structure of principal parts of vibration actuator1.FIG. 5is a perspective view showing a state in which the cover actuator and the FPC of the vibration are removed,FIG. 6is a perspective view showing the structure of the principal parts of the movable part from which the weight is removed, andFIG. 7is a bottom perspective view of the principal parts of the movable part inFIG. 6.

In this embodiment, an orthogonal coordinate system (X, Y, Z) will be used for explanation. The drawings described below (including drawings used for explaining Embodiments 2 and 3) also use common orthogonal coordinate system (X, Y, Z). In the description below, the width, length, and height of vibration actuator1are lengths in direction X, direction Y, and direction Z, respectively. In addition, positive direction Z indicates “upper side”, and negative direction Z indicates “lower side” for explanation. Further, a “side of the movable part” in this embodiment refers to a direction that is perpendicular to direction Z and extends radially from the movable part, in this embodiment, direction X, negative direction X, or direction Y extending radially from the movable part.

Vibration actuator1is mounted in a portable device, such as a smartphone (seeFIGS. 16A and 16B), as a vibration source and implements the vibrating function of the portable device. Vibration actuator1is driven to vibrate, for example, for notifying a user of an incoming call or giving the user an operational feeling or realism. Vibration actuator1is mounted so that in a portable device, for example, the vibration transmitting surface to be in contact with the user is parallel to the XY face. In a portable device, such as a smartphone or tablet terminal, for example, the vibration transmitting surface is a touch panel face, and in a wearable terminal mounted on user's clothing or arms, it is an outer surface to be in contact with the clothing or arms (inner peripheral surface605in FIG.16A).

As shown inFIGS. 1 to 4, vibration actuator1includes fixing part10, movable part20, and elastic supporting body30. Fixing part10is coupled to movable part20through elastic supporting body30so that the other end reciprocates with one end as a fulcrum, and supports movable part20.

In this embodiment, fixing part10has magnet11, and movable part20has coil21. In other words, vibration actuator1employs a voice coil motor (VCM) of a moving-coil system. It should be noted that vibration actuator1may use a voice coil motor of a moving-magnet system in which fixing part10has a coil and movable part20has a magnet.

Base plate13is composed of a plate, such as a steel plate (a rectangular plate in this embodiment), and includes rectangular plate body131constituting the bottom face of vibration actuator1, and a side end wall133with which one end of elastic supporting body30is fixed on a side (here, a back side) of movable part20. It should be noted that side end wall133is disposed on the back side of movable part20, side walls of cover15are disposed on sides opposed along the width, and a front end wall of cover15is disposed on a front end side opposed to the back side, that is, on a free end side.

First magnet111is fixed on plate body131and movable part20is opposed to and separated from plate body131.

As shown inFIGS. 1 to 5, side end wall133in this embodiment is integrated with plate body131such that it curves and stands up from an end of plate body131on one side (on the back).

Side end wall133is opposed to and separated from an end surface on the base end side of movable part20.

Cover15is compatible with base plate13and has a shape of a box (a cornered box in this embodiment) opened on base plate13side. Both side walls and a front end wall of cover15constitute a basal section (hereinafter referred to as “top section” for convenience), both side sections separated in the width direction, and a front end side section, which is a side section on the front end side, of vibration actuator1.

Attaching cover15to base plate13forms a housing (case) in the shape of a box (cornered box in this embodiment) of vibration actuator1. In this embodiment, vibration actuator1, which may have any external shape and dimensions, is formed into a rectangular parallelepiped shape in which, among the width (direction X), the length (direction Y), and the height (direction Z), the length is longest and the height is shortest. Components, including movable part20, are contained in a space defined by base plate13and cover15.

Base plate13and cover15are preferably composed of a conductive material. Thus, base plate13and cover15serve as an electromagnetic shield, and serve as a yoke constituting a magnetic circuit together with magnet11.

In addition, base plate13and cover15are each provided with damper material45to be in contact with vibrating movable part20on the free end side of movable part20.

Damper materials45come in contact with weight23of movable part20when movable part20vibrates, thereby transmitting vibrations of movable part20to base plate13and cover15which serve as a housing of vibration actuator1(seeFIGS. 10B and 10C). Hence, damper materials45can generate significant vibrations of the housing. Damper materials45are composed of a soft material, such as an elastomer, rubber, resin, or a porous elastic member (for example, sponge). In this embodiment, damper materials45are provided to base plate13and cover15. Alternatively, damper materials45may be provided to movable part20side, here, weight23, so that it comes in contact with base plate13and cover15when movable part20vibrates.

Magnet11consists of two magnets111and112. Among magnets111and112in the state where vibration actuator1is assembled, magnet111located on the upper side (cover15side) is referred to as first magnet111, and magnet112located on the lower side (base plate13side) is referred to as second magnet112.

First magnet111and second magnet112have substantially the same shape (a rectangular parallelepiped having longer sides along the length direction in this embodiment) and are joined to each other in such a manner that their magnetization directions are opposite. In other words, first magnet111and second magnet112are opposed and joined to each other on the same magnetic pole. In this embodiment, first magnet111and second magnet112are joined to each other in such a manner that their magnetization directions are opposite. Alternatively, they may be separated from each other in such a manner that their magnetization directions are opposite.

In this embodiment, first magnet111and second magnet112are magnetized in such a manner that the north pole resides on the joining surface side and the south pole resides on cover15or base plate13side. It should be noted that “substantially the same” means that first magnet111and second magnet112have the same external shape but may have different structures in detail (for example, depressed portions111aand112aformed in the joining surface (seeFIG. 3)).

In addition, first magnet111and second magnet112are located a predetermined distance away from coil21radially inside coil21. Here, a “radial direction” refers to a direction orthogonal to the coil axis (direction Z). A “predetermined distance” refers to a distance within which movement (oscillation) of coil21in direction Z with respect to first magnet111and second magnet112is permitted. It should be noted that coil21is disposed in such a manner that its top flushes with a joint portion between first magnet111and second magnet112in the state where vibration actuator1is assembled.

In the case where first magnet111and second magnet112are magnetized in such a manner that the north pole resides on the joining surface side and the south pole resides on cover15or base plate13side, a magnetic flux emerging from a central portion of magnet11along direction Z (joint portion) and entering both ends distanced along direction Z (upper end and lower end) is formed. Consequently, an outward magnetic flux crosses every part of coil21; thus, upon energization of coil21, the Lorentz force acts in the same direction. For example, when coil21is energized as shown inFIG. 10B, the upward Lorentz force acts on coil21. When coil21is energized as shown inFIG. 10C, the downward Lorentz force acts on coil21.

First magnet111and second magnet112are joined to each other with an adhesive, for example. In other words, there is an adhesive layer (whose reference numeral is omitted) between first magnet111and second magnet112. The adhesive used here may be composed of an ultraviolet-curable resin, thermosetting resin, or anaerobically-curable resin, for example. With an ultraviolet-curable adhesive (based on an acrylic resin or epoxy resin), which can be cured by ultraviolet irradiation in a short time, the takt time and the number of steps can be reduced. Meanwhile, with a thermosetting adhesive (based on an epoxy resin or acrylic resin) or anaerobically-curable adhesive (based on an acrylic resin), the bonding strength can be increased. In this embodiment, first magnet111and second magnet112are joined to each other with a thermosetting adhesive based on an epoxy resin. With an ultraviolet-curable adhesive, the central portion of the adhesive layer is barely irradiated with ultraviolet light, which may result in insufficient curing. Similarly, with an anaerobically-curable adhesive, magnet11is made compact and has a smaller area not exposed to air, which may result in insufficient curing. In contrast, with a thermosetting adhesive based on an epoxy resin, reliable curing can be achieved by heating, thereby stabilizing the manufacturing process and improving the productivity and reliability.

In this embodiment, first magnet111and second magnet112have depressed portions111aand112ain their joining surfaces, respectively. With this configuration, depressed portions111aand112aserve as a resin pit, thereby making an adhesion area greater and increasing the adhesive strength. Accordingly, the impact resistance is improved and the reliability increases. In addition, adhesive oozing is reduced and workability is therefore improved. Moreover, since depressed portions111aand112aare provide on magnetic pole surfaces that have the same magnetic poles, they can also be used as markings for identifying the magnetization directions of first magnet111and second magnet112.

In the case where first magnet111and second magnet112are joined to each other with an adhesive in such a manner that their magnetization directions are opposite, an excessive amount of applied adhesive results in a larger gap between the magnets and affects the vibrational characteristics, or an insufficient amount of applied adhesive cannot provide adequate bonding strength, leaving the risk of damage in the magnets upon vibration. In this embodiment, such problems are solved by forming depressed portions111aand112ain the joining surfaces of first magnet111and second magnet112, respectively.

Note that only at least one of first magnet111and second magnet112needs to have depressed portion111aor112a, and depressed portions111aand112amay have different shapes and may be formed into a cross shape instead of a linear shape which is adopted in this embodiment. Depressed portions111aand112ain a cross shape collect a larger amount of adhesive, so that the adhesive strength can be effectively made higher than in the case where they have a linear shape. On the other hand, depressed portions111aand112ain a linear shape are readily machinable, resulting in a stable shape, suppressing variations between individual workpieces, and imparting stable quality to magnet11.

Second magnet112is fixed to a predetermined position on plate body131of base plate13, for example, with a thermosetting adhesive such as an epoxy resin. In addition, first magnet111is fixed to a predetermined position on cover15, for example, by inserting magnet11in movable part20and attaching cover15to the workpiece, and then injecting an adhesive from an injection hole (whose reference numeral is omitted) of cover15.

Movable part20vibrates (oscillates) in vibration actuator1during operation. To be specific, with elastic supporting body30, the free end of movable part20vibrates with respect to fixing part10in a direction orthogonal to the vibration transmitting surface, here, in the vertical direction corresponding to direction Z.

One end of movable part20(here, an end of coil holder22on the back) is coupled to side end wall133of base plate13of fixing part10through plate spring member33of elastic supporting body30at the side of movable part20, and the other end is a free end. Movable part20is disposed inside the housing intermediately between base plate13and the top section of cover15in such a manner that it is cantilevered substantially parallel to base plate13and the top section of cover15. In other words, elastic supporting body30has a structure for cantilevering movable part20movably in the vibration direction (direction Z).

Movable part20includes coil21, coil holder22, weight23, and reinforcing member28. In this embodiment, weight fixer member31and holder attaching member (movable part fixer member)32of elastic supporting body30(the details will be described later) also constitute movable part20and oscillate as movable part20.

Movable part20faces base plate13and the top section of cover15in a non-energized state. When coil21is energized, movable part20reciprocates in the height direction (direction Z) to move toward and away from base plate13(specifically plate body131) and the top section of cover15(seeFIGS. 10B and 10C).

FIG. 6is a perspective view showing the structure of principal parts of movable part20from which weight23is removed, andFIG. 7is a bottom perspective view of the structure of the principal parts of movable part20shown inFIG. 6.FIG. 8is a diagram for explaining an attachment structure of FPC40, coil holder22, and elastic supporting body30.

Coil holder22shown inFIGS. 2 to 7is a connecting part used to connect coil21to elastic supporting body30. Coil holder22includes coil container222for containing coil21, container fixer members224, and board insertion member (insertion member)226(seeFIGS. 3 to 5).

In this embodiment, coil holder22is composed of a resin material. Thus, electrical insulation between coil holder22and other metal members (for example, elastic supporting body30) is ensured, thereby improving reliability. In addition, since coil holder22is attached to elastic supporting body30with coil21fixed, coil21is prevented from deforming and/or becoming loose and the workability and ease of attachment can be improved.

The resin material is preferably a liquid crystal polymer or polyphenylene sulfide resin (PPS resin), for example. With the use of a highly-fluid liquid crystal polymer or PPS as the resin material for coil holder22, coil holder22can be made thinner while its strength is maintained, thereby saving space. This increases the flexibility in designing coil21and magnet11and increases the vibrational output of vibration actuator1. In addition, since a liquid crystal polymer and PPS resin have excellent heat resistance and mechanical strength, the reliability also improves.

Coil container222in this embodiment is formed into a rectangular parallelepiped frame shape that is opened on both sides extending along the length direction (direction Y), and the outer peripheral surface and upper end surface of coil21are fixed to the inner surface of coil container222. The upper surface of coil container222is formed into a frame with opening222a(seeFIG. 3) through which magnet11can be inserted.

Coil container222has end face sections (222band222c) extending vertically downward from the top surface on both sides separated along the length direction (direction Y). For convenience, end face section (222b) on the back of coil container222will be hereinafter referred to as base end face section222bwhich is adjacent to the fixed end that is fixed to plate spring member33, and end face section (222c) which is opposite from the back and adjacent to the free end will be hereinafter referred to as front end face section222c.

Ribs protruding toward the back (in direction Y) from both sides separated along the width direction (direction X) are provided on the outer surface (the surface on the back) of base end face section222bof coil container222. Base end face section222band the ribs stabilize the mounting position of coil21and improve the mounting accuracy when coil21is mounted inside coil container222, that is, on the inner side of base end face section222band the ribs. Consequently, regarding vibration actuator1, the vibrational output can be stabilized between finished products. Moreover, positioning of coil21is easier, so that the workability improves. In addition, since nothing resides between coil21and magnet11, coil21and magnet11can be brought close to each other, which is preferable in terms of increasing the vibrational output of vibration actuator1.

Container fixer members224in this embodiment are provided on the top surface of coil container222. Container fixer members224are protrusions provided on the top surface of the frame of coil container222and on sides opposed along the length direction (direction Y), and are positioned when inserted in insertion holes322in frame-like holder attaching member32of elastic supporting body30stacked on that top surface.

As shown inFIG. 3,FIG. 4, andFIGS. 6 to 8, connection board42of flexible printed circuit board40(hereinafter referred to as “FPC40”) to be electrically connected to coil21is inserted in board insertion member226and is thus fixed. Hence, both ends of coil21and connection board42of FPC40can be disposed in predetermined positions, for example, near base end face section222b.

Board insertion member226is formed into a shape that protrudes outward (toward the back) from both sides of base end face section222bof coil container222. Connection board42is inserted to board insertion member226from above and engaged with it. In this embodiment, connection board42is overlaid on the outer surface of base end face section222band engages with base end face section222band board insertion member226.

Wiring of connection board42of FPC40inserted in board insertion member226is connected to both ends of coil21drawn outward from the interior of coil container222through groove223formed in a bottom end portion of base end face section222b, by soldering, for example. With this structure, both ends of coil21can be drawn outward from the interior of coil container222through groove223in base end face section222band connected to FPC40by soldering or the like, so that a connection between FPC40and coil21can be easily established from the outside of movable part20. Since both ends of coil21are disposed in groove223, both ends of coil21do not interfere with vibration of movable part20.

Since coil holder22has board insertion member226, fixation of FPC40to coil holder22can be made strong. Moreover, both ends of coil21can be easily joined to wiring of FPC40strongly held by board insertion member226by soldering or bonding, so that workability is enhanced and manufacture with stable reliability can be achieved.

Coil21is an air-core coil which is energized during operation, and constitutes a voice coil motor together with magnet11. Coil21is formed, for example, by winding and fusing self-welding wires. Coil21is attached to holder attaching member32of elastic supporting body30through coil holder22.

Coil21has a shape that contours to the inner peripheral surface of coil container222, that is, a shape that contours to a region (here, in a substantially rectangular shape) defined by the top surface, base end face section222b, front end face section222c, and ribs. Hence, coil21can be easily attached to coil holder22. To be specific, coil21can be easily fixed to the top surface of coil container222and end face sections (base end face section222band front end face section222c), for example, by bonding at the top surface of coil21and both end surfaces of coil21separated along the length direction (the end surface adjacent to the base end and the end surface adjacent to the front end).

In assembled vibration actuator1, magnet11is disposed radially inside coil21with a predetermined gap therebetween as described above. In this case, coil21is located around a joint portion between first magnet111and second magnet112.

Both ends of coil21are connected to connection board42of FPC40by drawing groove223of base end face section222bof coil container222to the exterior. Coil21is energized via this FPC40.

Weight23is a weight for increasing the vibrational output of movable part20. Weight23is preferably disposed adjacent to the free end of movable part20. Weight23in this embodiment has an arrowhead-like shape and is tapered so that the top and bottom surfaces get closer toward the free end, that is, front end. Hence, the thickness of weight23in the vibration direction decreases toward the free end. Weight23is provided continuous from weight fixer member31of elastic supporting body30along a direction in which weight fixer member31extends, and is disposed adjacent to coil21with coil holder22therebetween.

An end portion of weight23on the back is an elastic fixer member232to which weight fixer member31of elastic supporting body30is fixed. Elastic fixer member232is thinner than a portion of weight23extending out from elastic supporting body30, here, the tapered portion by a thickness of weight fixer member31of elastic supporting body30so that when it is coupled to elastic supporting body30through weight fixer member31, their surfaces (here, the top surfaces) flush with each other.

In weight23, front and rear surfaces (surfaces separated along the vibration direction, that is, direction Z, and corresponding to top and bottom surfaces here) adjacent to the free end and continuous to elastic fixer member232are tapered to converge toward the front end. These tapered faces are provided so that they become substantially parallel to the top and bottom surfaces of the housing when movable part20vibrates. Accordingly, weight23can vibrate within a wider space in the housing than in the case where a weight having the same thickness in direction Z as weight23and having, in a reference position, flat top and bottom surfaces parallel to the opposed top and bottom surfaces of the housing is used for vibrating movable part20within the same oscillation range. In addition, regarding weight23having tapered top and bottom surfaces, increasing the thickness between the top and bottom surfaces from the free end toward the back can yield a higher weight of movable part20compared with use of a weight having flat and parallel top and bottom surfaces. Accordingly, higher vibrational output can be obtained.

An end portion of weight23on the back is provided with elastic fixer member232on top and bottom surfaces and elastic fixer member232is formed into the same shape on the top and bottom surfaces. Hence, upon fixation of weight23to elastic supporting body30, weight fixer member31and elastic fixer member232can be fixed to each other regardless of directions the top and bottom surfaces of weight23face. Weight fixer member31and elastic fixer member232are bonded and fixed to each other using an adhesive such as thermosetting adhesive, for example. Alternatively, weight fixer member31and elastic fixer member232may be fixed to each other by welding. It should be noted that weight fixer member31and elastic fixer member232may be joined to each other, for example, by being swaged together with a rivet of a copper-based material (copper or copper alloy) or stainless material.

It is preferable that weight23be composed of a material whose specific gravity (for example, specific gravity of about 16 to 19) is higher than a material of an electrogalvanized steel plate (SECC; the specific gravity of the steel plate is 7.85) or the like. Tungsten, for example, can be used as a material for weight23. With such a material, even in the case where the dimensions of the external shape of movable part20are set at design time or the like, the mass of movable part20can be increased comparatively easily and a desired vibrational output can be achieved.

During oscillation, the front end portions of the tapered portions of the top and bottom surfaces of weight23(portions to come into collision with base plate13and cover15) come into collision with damper materials45.

This relieves the impact caused when vibrating movable part20comes into contact with base plate13or cover15, thereby allowing vibrations to be transmitted to the user while reducing a contact sound or vibrational noise. Besides, since movable part20comes into contact (specifically, collision) alternately with base plate13and cover15through damper materials45each time it vibrates, the vibrational output is amplified. Hence, the user can sense a vibrational output greater than the actual vibrational output of movable part20. Moreover, since base plate13is a member mounted on the user, vibrations of movable part20are directly transmitted to the user through base plate13and the user can sense a still greater vibrational output.

FPC40extends along plate spring member33of elastic supporting body30and is drawn to the exterior of cover15from the base end side of plate spring member33.

FPC40includes connection board42connected to coil21, and FPC body41that is disposed along plate spring member33, is connected to connection board42, and has one end extending to the exterior of cover15.

FPC body41is connected to connection board42via joint board43. Joint board43laterally extends from the other end portion of FPC body41so that it surrounds plate spring member33, which is below FPC body41, from below.

In particular, as shown inFIG. 8, joint board43is disposed so that it surrounds top and bottom surfaces of plate spring member33from one side and engages with plate spring member33. Hence, joint board43serves as an engaging member to engage with plate spring member33so that making FPC body41barely separated from plate spring member33in direction Z. Further, a part of joint board43below plate spring member33is connected to connection board42in such a manner that connection board42is bendable.

Thus, in FPC40, with FPC body41placed on plate spring member33, joint board43can be engaged with spring member33and connection board42can be inserted in and held in board insertion member226below plate spring member33. FPC40deforms following the vibrations of movable part20.

It should be noted that in FPC40, an elastic member, such as an elastic adhesive or elastic adhesive tape, for example, may be placed between FPC body41and plate spring member33so that the elastic member absorbs the impact during vibration.

Elastic supporting body30includes weight fixer member31and holder attaching member32in addition to plate spring member (elastic supporting part)33that supports movable part20movably with respect to fixing part10. Weight fixer member31, holder attaching member32, and plate spring member33are integrally formed, for example, by sheet-metal working of a stainless steel plate. Note that, during operation, plate spring member33deforms and weight fixer member31and holder attaching member32vibrate integrally with coil21, weight23, and the like. Weight fixer member31and holder attaching member32are parts of movable part20as described above. Note that weight fixer member31, holder attaching member32, and plate spring member33may be different members. Alternatively, two adjacent members may be integrally formed and the remaining member may be a different member.

Weight fixer member31and holder attaching member32have a plate-like shape as well as plate spring member33, and holder attaching member32and weight fixer member31are continuously provided in the order presented from the other end of plate spring member33.

Weight fixer member31is a member to which weight23is connected. Weight fixer member31is in surface-contact with elastic fixer member232and fixed on the upper surface of weight23.

Holder attaching member32fixes coil holder22, which contains coil21, to elastic supporting body30. Holder attaching member32is provided at the other end of main surface section331of plate spring member33and protrudes continuously from main surface section331in a direction in which main surface section331extends, thereby constituting a movable part fixer member. Holder attaching member32forms a frame with opening321(seeFIG. 3) through which magnet11is inserted. Holder attaching member32has insertion holes322, which extend in the width direction, on sides separated along the length direction. Container fixer members224are inserted in insertion holes322. Thus, with coil holder22positioned on the bottom surface of holder attaching member32, coil holder22is fixed, for example, by bonding.

Further, holder attaching member32is provided with reinforcing member28for increasing the rigidity of holder attaching member32.

Reinforcing member28is a frame with opening281in the same shape as opening321of holder attaching member32and is fixed on the top surface of holder attaching member32for reinforcing the top surface of the frame of holder attaching member32. Reinforcing member28in this embodiment is fixed on the top surface of holder attaching member32by welding. A configuration in which reinforcing member28is fixed on holder attaching member32by welding is not necessarily the case: it may be fixed by bonding, sticking, or the like, or integrally formed therewith.

Holder attaching member32is formed into a frame with opening321and therefore has low rigidity. Such low rigidity may cause fluctuations in resonance frequency or a decrease in reliability of the operation of vibration actuator1. Holder attaching member32in this embodiment is a frame disposed in a narrow space around the magnet but has high rigidity produced by reinforcing member28, thereby achieving high stability of the operation of vibration actuator1.

Plate spring member33has a plate-like shape and deforms during operation. Plate spring member33corresponds to an elastic supporting part. One end of plate spring member33is fixed to fixing part10at the side of movable part20, and the other end is fixed to movable part20, thereby cantilevering movable part20in such a manner that it can reciprocate in the vibration direction.

Plate spring member33in this embodiment includes plate-like main surface section331extending from movable part20toward one side, here, the back side, and main surface fixer member333provided at one end of main surface section331and fixed to fixing part10, for example, by wielding or bonding.

Plate spring member33has an L shape in which main surface fixer member333bends down perpendicularly from one end of main surface section331.

The other end of main surface section331is connected to coil21through coil holder22attached to holder attaching member32, and to weight23attached to weight fixer member31.

Main surface fixer member333is a planar member fixed to side end wall133of fixing part10by welding or bonding. In this embodiment, main surface fixer member333is fixed in the state where it is in surface-contact with the outer surface of side end wall133. Main surface fixer member333is fixed to side end wall133, for example, by welding or bonding.

Since main surface fixer member333is fixed on the outer surface of side end wall133as described above, one end of elastic supporting body30joined to movable part20, that is, main surface fixer member333can be easily fixed to fixing part10by welding or bonding from the exterior of vibration actuator1.

In addition, side end wall133and main surface fixer member333stacked on the outer surface of side end wall133may be provided with a through hole for welding and they may be fixed together by piercing welding in such a manner that it is sandwiched with a component disposed on the outer surface of main surface fixer member333. On the inner side of side end wall133, a space is formed under plate spring member33and no impact of welding occurs. Further, the coefficient of elasticity of main surface section331can be adjusted by adjusting the area of welding of main surface fixer member333with respect to side end wall133.

[Magnetic Circuit of Vibration Actuator1]

FIG. 9is a diagram showing the magnetic circuit of vibration actuator1.FIGS. 10A to 10Care longitudinal sectional views showing the operation of movable part20.FIGS. 10A to 10Crespectively illustrate a state of movable part20where movable part20is not energized (reference state), a state of movable part20where coil21is energized with a clockwise current as seen from above, and a state of movable part20where coil21is energized with a counterclockwise current as seen from above.

In vibration actuator1, one end of movable part20is supported by plate spring member33of elastic supporting body30between base plate13and cover15of fixing part10. In addition, magnet11is disposed radially inside coil21of movable part20, and first magnet111and second magnet112are joined to each other so that their pole faces of the same polarity (the north pole inFIGS. 9 and 10A to 10C) face each other.

Movable part20reciprocates in direction Z (that is, in a direction along which movable part20moves toward and away from base plate13and cover15) when coil21is energized by a power supplying part (not shown in the drawing) via FPC40. In particular, the other end portion of movable part20oscillates. In this way, the vibrational output of vibration actuator1is transmitted to the user of the portable device provided with vibration actuator1.

The magnetic circuit shown inFIG. 9is formed in vibration actuator1. In addition, in vibration actuator1, coil21is provided perpendicular to the magnetic fluxes from first magnet111and second magnet112. Accordingly, when energization is performed as shown inFIG. 10B, Lorentz force F is generated in coil21by interaction between the magnetic field of magnet11and the current flowing through coil21in accordance with the Fleming's left hand rule. The direction of Lorentz force F is a direction (positive direction Z inFIG. 10B) that is orthogonal to the direction of the magnetic field and to the direction of the current flowing through coil21. With this Lorentz force F serving as a thrust, movable part20oscillates. To be specific, since one end of movable part20is supported by elastic supporting body30(plate spring member33), the other end (that is, weight23) of movable part20moves in positive direction Z as a result of oscillation. Afterwards, the front end of weight23in movable part20comes into contact (specifically, collision) with cover15via damper material45.

Moreover, when the energizing direction in coil21is reversed and energization is performed as shown inFIG. 10C, inverse Lorentz force −F (in negative direction Z) is generated. With this Lorentz force −F serving as a thrust, movable part20oscillates. To be specific, the other end (that is, weight23) of movable part20moves in negative direction Z as a result of oscillation, and the front end of weight23comes into collision with damper material45and comes into contact (specifically, collision) with base plate13itself via damper material45.

In vibration actuator1, movable part20is movably supported by a structure in which one end of plate spring member33is fixed to movable part20and the other end is fixed to fixing part10.

To be specific, one end of plate spring member33is fixed on a side surface (side end wall133) of fixing part10at the side of movable part20; thus, deterioration of the planarity of plate body131can be avoided, for example, by leaving welding marks or the like by machining plate body131of base plate13constituting the bottom face of the housing of fixing part10. Moreover, in vibration actuator1, welding from the bottom face of the housing is unnecessary, so that upon attachment of plate spring member33to fixing part10, plate spring member33joined to movable part20and fixing part10can be joined together by welding or the like at the side of vibration actuator1without turning the housing of vibration actuator1to expose the bottom face; thus, high productivity can be obtained.

Further, in this embodiment, plate spring member33, that is, elastic supporting body30is formed by bending a metal plate into an L shape which ensures elasticity, eliminating the need for machining, such as complex bending, performed as spring machining for ensuring elasticity. In this way, the part accuracy of elastic supporting body30including plate spring member33is enhanced, stabilizing the performance.

In addition, the space occupied by plate spring member33in the housing is saved as much as possible so that movable part20, and coil21and magnet11serving as a vertical vibration generator can be made big and vibration actuator1can be made compact, while yielding high output.

In addition, in vibration actuator1, coil21and magnet11are disposed adjacent to the base end of movable part20(to which plate spring member33is joined), and weight23is disposed adjacent to the front end of movable part20. In other words, the magnetic circuit for generating a driving torque of movable part20is disposed adjacent to the fulcrum for oscillation, and weight23is disposed adjacent to the front end of movable part20at which displacement occurs in the widest range during oscillation. Hence, compared with a configuration in which coil21and magnet11are disposed adjacent to the front end of movable part20, weight23disposed adjacent to the front end can occupy a wide area and movable part20can be given a great rotational moment (mass in a rotating system), so that a high vibrational output can be achieved. This provides adaptability to a limitation on the height in direction Z and a limitation on the range of motion (amount of vibration) of movable part20due to a reduction in the height of vibration actuator1.

Further, since weight23has an arrowhead-like shape in which the thickness in direction Z decreases toward the free end, compared with use of a weight in a rectangular parallelepiped shape in which the top and bottom surfaces are parallel to each other, a high range of motion is achieved during oscillation, thereby ensuring higher vibrational output.

Moreover, unlike in a vibration actuator in which a movable part vibrates while sliding on a fixing part, movable part20vibrates without sliding on a part of fixing part10, so that attenuation in thrust due to frictional resistance to fixing part10does not occur during vibration, leading to preferable vibration.

In this way, a simple supporting structure is provided, which simplifies the design and saves space; thus, vibration actuator1can be made compact.

Here, vibration actuator1is driven by AC waves input to coil21from the power supplying part (not shown) via FPC40. In other words, the energizing direction of coil21periodically switches and thrust F in positive direction Z and thrust −F in negative direction Z alternately act on movable part20. Thus, the other end of movable part20vibrates along an arc over the YZ plane.

A brief description will now be given of the driving principle of vibration actuator1. In vibration actuator1of this embodiment, movable part20vibrates with respect to fixing part10at resonance frequency fr[Hz] calculated by equation 1 below where J [kg·m2] is the moment of inertia of movable part20and Kspis the spring constant of plate spring member33in the torsional direction.

J: Moment of inertia [kg·m2]

Since movable part20is a mass in a vibration model of a spring-mass system, movable part20is brought into a resonance state when AC waves of a frequency equal to resonance frequency frof movable part20are input to coil21. In other words, movable part20can be efficiently vibrated by inputting AC waves of a frequency substantially equal to resonance frequency frof movable part20to coil21from the power supplying part.

The motion equation and circuit equation representing the driving principle of vibration actuator1are shown below. Vibration actuator1is driven based on the motion equation represented by equation 2 below and the circuit equation represented by equation 3 below.

J: Moment of inertia [kg·m2]

In other words, moment of inertia J [kg·m2], angle of rotation θ(t) [rad], torque constant Kt[N·m/A], current i(t) [A], spring constant Ksp[N·m/rad], damping coefficient D [N·m/(rad/s)], and the like of movable part20in vibration actuator1may be changed appropriately as long as equation 2 is satisfied. Voltage e(t) [V], resistance R [Ω], inductance L [H], and counter electromotive force constant Ke[V/(rad/s)] may also be changed appropriately as long as equation 3 is satisfied.

As described above, in vibration actuator1, high vibrational output can be efficiently obtained when coil21is energized using AC waves corresponding to resonance frequency frdetermined by moment of inertia J of movable part20and spring constant Kspof plate spring member33.

FIG. 11is a perspective view of an external appearance of a vibration actuator according to Embodiment 2 of the present invention.FIG. 12is a perspective view showing a state in which the cover of the vibration actuator according to Embodiment 2 of the present invention is removed.FIG. 13is an exploded perspective view of the vibration actuator according to Embodiment 2 of the present invention.FIG. 14is a longitudinal sectional view showing the structure of principal parts of the vibration actuator according to Embodiment 2 of the present invention.FIG. 15is a bottom view of the vibration actuator from which a base plate is removed.

Actuator1A of Embodiment 2 differs from actuator1of Embodiment 1 in that one end of its elastic supporting body30corresponds to back end portions152and153of side walls (here, side walls of cover15) separated along the width direction of the housing, instead of side end wall133. The basic structure of actuator1A is similar to that of actuator1. Therefore, a structural part different from that of actuator1will be described and a component providing the same effects as the corresponding component in actuator1is denoted by the same name and reference numeral as that component and its description will be omitted.

Like vibration actuator1, vibration actuator1A is mounted in a portable device, such as a smartphone (seeFIGS. 16A and 16B), as a vibration source and implements the vibrating function of the portable device.

Vibration actuator1A shown inFIGS. 11 to 15includes fixing part10A, movable part20A, and elastic supporting body30A. Fixing part10A is coupled to movable part20A through elastic supporting body30A so that the other end reciprocates with one end as a fulcrum, and supports movable part20A. In vibration actuator1A, with the same magnetic circuit configuration as vibration actuator1, when current is supplied to coil21, movable part20A vibrates in a vibration area in direction Z like vibration actuator1.

Fixing part10A is different from fixing part10in Embodiment 1 in that it includes base plate13A instead of base plate13. Fixing part10A supports movable part20A through elastic supporting body30A, and includes magnet11, base plate13A, and cover15.

Base plate13A constitutes a housing together with cover15. Base plate13A includes rectangular plate body131A constituting the bottom face of vibration actuator1, and side end wall133A standing up from a side of movable part20of plate body131A, here, the back side.

Side end wall133A covers the back end surface of the housing of vibration actuator1A. Like in the case of plate body131, magnet11and damper material45are fixed to plate body131A of base plate13A.

Cover15is provided so that it covers base plate13A, and constitutes the top section of the housing of vibration actuator1A, both side sections separated along the width direction, and a front end side section which is a side section on the front end side.

On the front end of the top section of cover15, damper material45is provided in a position opposed to damper material45of plate body131A.

One end of elastic supporting body30A is fixed to the inner sides of back end portions152and153of the both side walls of cover15. Like in Embodiment 1, base plate13A and cover15are preferably composed of a conductive material.

Movable part20A has a function similar to that of movable part20. Movable part20A is disposed inside the housing intermediately between base plate13A and the top section of cover15in such a manner that it is cantilevered substantially parallel to base plate13and the top section of cover15. With elastic supporting body30A, the free end of movable part20A vibrates with respect to fixing part10A in a direction orthogonal to the vibration transmitting surface (for example, plate body131A of base plate13A or top section of cover15), here, in the vertical direction corresponding to direction Z.

Movable part20A of this Embodiment 2 includes coil21, coil holder22A, and weight23A which have functions similar to those of the respective components of movable part20having the same names. In this embodiment, weight fixer member31A and holder attaching member32A of elastic supporting body30A also constitute a part of movable part20and oscillate as movable part20. Movable part20A faces base plate13A and the top section of cover15in a non-energized state. Like in Embodiment 1, when coil21is energized, movable part20A reciprocates in the height direction (direction Z) to move toward and away from base plate13A and the top section of cover15.

Coil holder22A of this embodiment is held in such a manner that it surrounds and contains coil21with holder attaching member32A of elastic supporting body30A. Coil holder22A is connected to elastic supporting body30A so that coil21is attached to elastic supporting body30A. Coil holder22A includes coil container222A for containing coil21, container fixer member224A on the top surface of coil container222A, and tying parts226A (seeFIGS. 13 to 14).

In this embodiment, coil holder22A is composed of the same resin material and has the same function as coil holder22.

Coil container222A in this embodiment includes a rectangular frame-like bottom face having an opening through which magnet11is passed to bottom face222Aa, and end face sections (base end face section222Ab and front end face section222Ac) standing up from both sides separated along length direction (direction Y) of bottom face222Aa. Like in Embodiment 1, base end face section222Ab, which is an end face section adjacent to the fixed end, and front end face section222Ac, which is an end face section adjacent to the free end each have ribs, which protrude toward the opposed end face section, along sides separated along the width direction (direction X). Coil21is disposed and fixed on the inner side of bottom face222Aa, base end face section222Ab, and front end face section222Ac. Thus, coil21can be mounted in a stable position, providing the same effects as those provided by coil container222. In addition, in coil container222A, coil21can be contained with nothing between coil21and magnet11.

Container fixer members224A protrudes from the top surfaces of base end face section222Ab and front end face section222Ac. Container fixer members224A are provided on the top surfaces of base end face section222Ab and front end face section222Ac and extend along the length direction, and are positioned when inserted in insertion holes322A in frame-like holder attaching member32A of elastic supporting body30attached on the top surface.

Tying parts226A are connecting parts for electrically connecting coil21to FPC40A and protrude outward from coil container222A (specifically base end face section222Ab). Tying parts226A are connected to both ends of coil21and to the wiring of FPC40A, for example, by soldering. Since coil holder22includes tying parts226A, coil21can be always soldered to the same position on FPC40A outside coil21, so that high workability and stable manufacture can be achieved. In addition, since the ends of coil21are fixed to tying parts226A, coil21can be prevented from becoming loose. Tying parts226A in this embodiment, which are located directly below the front end of FPC40A, can be connected to the wiring of FPC40A when tied both ends of coil21are extended to directly above them. Coil21is energized through this FPC40A.

Front end face section222Ac of coil holder22A has weight receiving section228that receives weight engagement section238of weight23A. Weight receiving section228in this embodiment is a notch opened downward. When weight engagement section238is engaged with weight receiving section228, weight23A is positioned adjacent to coil holder22A. Coil holder22A and weight23A are fixed together by bonding or welding weight engagement section238and weight receiving section228together.

Weight23A has the same structure as weight23except that it has weight engagement section238on the end surface adjacent to the base end. In weight23A, elastic fixer member232A is provided on the back end and front and rear surfaces adjacent to the free end and continuous from elastic fixer member232A are tapered into arrowhead shapes.

Weight fixer member31A of elastic supporting body30A is fixed to elastic fixer member232A.

Weight engagement section238protrudes to the back from a flat end surface adjacent to the base end and fits the shape of weight receiving section228.

FPC40A extends along plate spring member33A of elastic supporting body30A and is drawn to the exterior of cover15from the base end side of plate spring member33A.

The structure of elastic supporting body30A is different from that of elastic supporting body30in that one end attached to fixing part10A corresponds to back end portions152and153of both side walls of cover15.

To be specific, elastic supporting body30A includes plate spring member (elastic supporting part)33A for supporting movable part20A movably with respect to fixing part10A, weight fixer member31A, and holder attaching member32A. Weight fixer member31A, holder attaching member32A, and plate spring member33A are integrally formed, for example, by sheet-metal working of a stainless steel plate, in the order presented to the back from the front end. Note that, during operation, plate spring member33A deforms and weight fixer member31A and holder attaching member32A vibrate integrally with coil21, weight23A, and the like. As described above, weight fixer member31A and holder attaching member32A constitute a part of movable part20A. In addition, regarding weight fixer member31A, holder attaching member32A, and plate spring member33A, one of them may be a different member. Alternatively, two adjacent members may be integrally formed and the remaining member may be a different member.

Weight fixer member31A is fixed by being in surface-contact with elastic fixer member232A on the upper surface of weight23A and elastic supporting body30A is connected to weight23A. Holder attaching member32A forms a frame with an opening321A (seeFIG. 13) through which magnet11is inserted and fixes coil holder22A containing coil21to elastic supporting body30A. Container fixer members224A are inserted in insertion holes322A of holder attaching member32A; thus, with coil holder22A positioned on the bottom surface of holder attaching member32A, coil holder22A is fixed, for example, by bonding.

Plate spring member33A has a plate-like shape and deforms during operation. Plate spring member33A corresponds to an elastic supporting part. One end of plate spring member33A is fixed to back end portions152and153of cover15of fixing part10A on sides of movable part20A (here, both sides opposed along the width direction), and the other end is fixed to movable part20A, thereby cantilevering movable part20A in such a manner that it can reciprocate in the vibration direction.

Plate spring member33A in this embodiment is fixed to back end portions152and153through main surface fixer member333A provided at one end of plate-like main surface section331A, which extends from movable part20A toward one side, here, the back side, for example, by wielding or bonding.

Main surface fixer member333A is continuous to main surface section331A in a planar manner, and includes fixer member top section3332extending in the width direction, and fixer legs3334extending vertically downward from ends of fixer member top section3332opposed along the width direction, thereby forming a U shape that opens downward when viewed along the length direction (direction Y).

A portion where main surface section331A extends from fixer member top section3332has slits. With slits in fixer member top section3332, the length of fixer member top section3332in a direction in which main surface section331A extends, here, direction Y can be made long, thereby allowing main surface section331A to be more easily deformed with elasticity.

Main surface fixer member333A is fixed to the inner sides of back end portions152and153of cover15through fixer legs3334by welding or bonding.

Hence, one end of elastic supporting body30A is fixed to fixing part10A and the cantilever structure allows movable part20A to be supported in such a manner that it can oscillate, without interfering with the movable range of movable part20A, providing the same advantageous effects as those provided by Embodiment 1.

FIGS. 16A and 16Bshow Embodiment 3 which is an example of exemplary mounting configurations of vibration actuator1.FIG. 16Ashows an example of vibration actuator1mounted in wearable terminal W, andFIG. 16Bshows another example of vibration actuator1mounted in mobile terminal M.

Wearable terminal W is worn for use by a user. Wearable terminal W here has a ring shape and is attached to a finger of the user. Wearable terminal W is wirelessly connected to an information communication terminal (for example, mobile phone). Wearable terminal W notifies the user of an incoming call and/or incoming mail on the information communication terminal through vibration. Note that wearable terminal W may be provided with functions other than incoming call notification (for example, a function of input to the information communication terminal).

Mobile terminal M is a portable communication terminal, such as a mobile phone or smartphone, for example. Mobile terminal M vibrates to notify the user of an incoming call from an external communication device and implement functions of mobile terminal M (for example, functions of giving operational feeling or realism).

As shown inFIGS. 16A and 16B, wearable terminal W and mobile terminal M each include communication section601, processing section602, drive control section603, and driving section604. Vibration actuator1is used as driving section604.

In wearable terminal W and mobile terminal M, vibration actuator1is mounted in such a manner that the XY face of vibration actuator1is parallel to the main surface of the terminal serving as a vibration transmitting surface. To be specific, in the case of wearable terminal W, vibration actuator1is mounted in such a manner that inner peripheral surface605of the annular housing serves as a main surface (a vibration transmitting surface) and the XY face is substantially parallel (including parallel) to inner peripheral surface605. In the case of mobile terminal M, vibration actuator1is mounted in such a manner that the XY face is parallel to the display screen (touch panel face) serving as a main surface to be in contact with the user. Hence, vibration perpendicular to inner peripheral surface605of wearable terminal W and the main surface of mobile terminal M which serve as vibration transmitting surfaces is transmitted to the user.

Communication section601is wirelessly connected to an external communication device, receives signals from the communication device, and outputs signals to processing section602. In the case of wearable terminal W, the external communication device is an information communication terminal, such as a mobile phone, smartphone, or portable game terminal, for example, and communication is performed according to a short-distance radio communication standard, such as Bluetooth (registered trademark). In the case of mobile terminal M, the external communication device is, for example, a base station, and communication is performed according to mobile telecommunications standards.

Processing section602converts input signals into driving signals for driving driving section604(vibration actuator1) through a conversion circuit section (not shown in the drawing), and outputs the driving signals to drive control section603. Note that, in mobile terminal M, processing section602generates driving signals based on signals input from communication section601and signals input from various function sections (which is not shown in the drawing and is, for example, an operation section such as a touch panel).

Drive control section603is connected to driving section604(FPC40of vibration actuator1) and is mounted with a circuit for driving driving section604. Drive control section603supplies driving signals to driving section604.

Driving section604is driven based on driving signals from drive control section603. To be specific, in vibration actuator1used as driving section604, movable part20vibrates perpendicularly to the main surfaces of wearable terminal W or mobile terminal M. Since movable part20comes into contact with base plate13or cover15every time it vibrates, the impact on base plate13or cover15caused by the vibration of movable part20is transmitted directly to the user as vibration. Since the vibration perpendicular to a body surface of the user is transmitted to the body surface in contact with wearable terminal W or mobile terminal M, sufficient physically-felt vibrations can be given to the user.

As described above, vibration actuator1according to this embodiment includes: movable part20including coil21; fixing part10including magnet11; and plate spring member33(elastic supporting part) configured to support movable part20movably with respect to fixing part10. Movable part20is configured to reciprocate with respect to fixing part10in a vibration direction through cooperation between coil21and magnet11. Magnet11is disposed away from and radially inside coil21. One end of plate spring member33is fixed to fixing part10and the other end is fixed to movable part20, constituting a structure in which movable part20is cantilevered. Coil21is incorporated in movable part20in the state where it is fixed to coil holder22composed of a resin.

According to vibration actuator1, sufficient physically-felt vibrations can be given to a user without increasing the size. In addition, since coil holder22is composed of a resin material, electrical insulation between coil holder22and other metal members (for example, elastic supporting body30) can be ensured, thereby improving reliability. In addition, since coil holder22is attached to elastic supporting body30with coil21fixed to coil holder22, coil21is prevented from deforming and/or becoming loose and the workability and ease of attachment can be improved.

The invention made by the present inventor has been specifically described based on the embodiments. The present invention should not be limited to the above-mentioned embodiments and modifications can be made without departing from the scope of the present invention.

In addition, for example, it is also preferable that vibration actuators1and1A according to the present invention be applied to portable devices other than wearable terminal W and mobile terminal M described in the embodiment (for example, portable information terminals, such as tablet PCs, portable game terminals, and controllers (game pads) of stationary game machines).

It should be understood that the embodiments disclosed herein are to be taken as illustrative only and do not limit the scope of the invention. The scope of the present invention should not be defined by the above-mentioned description but by the claims. Equivalents and all modifications of the claims should be included in the scope of the present invention.

REFERENCE SIGNS LIST

10,10A Fixing part

13,13A Base plate

20,20A Movable part

226Board insertion member

30,30A Elastic supporting body

31,31A Weight fixer member

131,131A Plate body

133,133A Side end wall

152,153Back end portion

222b,222Ab Base end face section

222c,222Ac Front end face section

222Aa Bottom face

224,224A Container fixer member

226Board insertion member

226A Tying part

228Weight receiving section

232,232A Elastic fixer member

238Weight engagement section

331,331A Main surface section

333,333A Main surface fixer member

3332Fixer member top section