JP7540271B2 - Vibration actuator and electronic device - Google Patents

Description

The present invention relates to a vibration actuator and an electronic device.

Conventionally, vibration actuators have been implemented in electronic devices as vibration sources that transmit vibrations to fingers, hands, feet, etc. to notify users of incoming calls, improve the feel of touch panels, and improve the realism of gaming devices such as game console controllers. Electronic devices include mobile communication terminals such as mobile phones and smartphones, mobile information terminals such as tablet PCs, portable game terminals, controllers (game pads) for stationary game consoles, as well as wearable terminals that are attached to clothing, arms, etc.

The vibration actuators disclosed in Patent Documents 1 to 3 include a fixed body having a coil and a movable body having a magnet, and generate vibrations by reciprocating the movable body using the driving force of a voice coil motor composed of a coil and a magnet. The vibration actuators shown in Patent Documents 1 to 3 are linear actuators in which the movable body moves linearly along a shaft, and are mounted so that the vibration direction is parallel to the main surface of the electronic device. Vibrations are transmitted to the surface of the user's body that comes into contact with the electronic device in a direction along the body surface.

Also, as a vibration actuator, a vibration actuator in which a movable body to be vibrated is supported by a cantilever, as disclosed in Patent Document 4, is known.
In this vibration actuator, the base end of a leaf spring is fixed to a fixed body, and a cylindrical magnet is placed inside a cup-shaped yoke at the tip of the leaf spring, which is the movable end, to form a movable body. A coil is also placed on the fixed body side, with its upper end positioned between the magnet and the edge of the yoke. The movable body vibrates when electricity is applied to the coil.

JP 2015-095943 A JP 2015-112013 A Patent No. 4875133 JP 2002-177882 A

Incidentally, a cantilever type vibration actuator in which a movable body is supported by a cantilever so that it can freely swing can have a simpler configuration than a configuration in which the movable body is supported by an axis or at multiple points.
In this configuration, in order to increase the sense of vibration, it is necessary to increase the thrust, i.e., the G value that indicates vibration, and to achieve this, it is conceivable to increase the thickness dimension of the magnet, i.e., increase its size, thereby increasing the magnetic flux in the magnetic circuit.
However, simply using a thick magnet makes the yoke prone to saturation, so it becomes necessary to make the yoke thicker. If the size of the magnet is set, this will have a significant effect on the dimensions of the movable body, resulting in reduced inertia and a higher resonance point.
Therefore, there has been a demand for increasing the inertia while maintaining the magnetic characteristics, thereby maintaining the resonance point and driving the motor.

The object of the present invention is to provide a vibration actuator and electronic device that can increase inertia without increasing size and generate suitable vibrations.

A vibration actuator according to one aspect of the present invention comprises:
a movable body including a coil and a core around which the coil is wound, the core extending in a winding axis direction of the coil and having one end and the other end protruding therefrom;
A fixed body having a magnet;
a shaft portion that supports the movable body rotatably relative to the fixed body at one end side of the core;
a vibration actuator having a structure in which the movable body rotates and vibrates reciprocally around the shaft portion relative to the fixed body by cooperation between the coil and the magnet when electricity is applied,
the magnet is disposed opposite at least one of the one end and the other end of the core in an extension direction of the core when not energized, and has two magnetic poles with different polarities aligned in a reciprocating rotational vibration direction,
The core has a notch on the other end side,
A weight portion is fixed to the cutout portion ,
The cutout portion is formed at the other end of the core so as to surround a core portion extending in an extension direction of the core,
The weight portion is configured by a plurality of divided bodies arranged in the cutout portion so as to surround the periphery of the core portion .

An electronic device according to one aspect of the present invention is configured to incorporate the vibration actuator described above.

The present invention allows the inertia to be increased without increasing the size, generating suitable vibrations.

1 is an external perspective view showing a vibration actuator according to an embodiment of the present invention. FIG. 2 is a perspective view showing a state in which the cover of the vibration actuator is removed. FIG. 2 is an exploded view showing a fixed body and a movable body in the vibration actuator. FIG. 2 is an overall exploded perspective view of the vibration actuator. 2 is a cross-sectional view taken along line A-A of FIG. 1. 6A and 6B are cross-sectional views for explaining the movable body. FIG. 2 is a cross-sectional plan view showing a magnetic circuit of the vibration actuator. 5A to 5C are cross-sectional plan views showing the operation of a movable body. FIG. 11 is a cross-sectional view showing a configuration of a main part of a first modified example of a vibration actuator. FIG. 11 is a partially exploded perspective view showing a configuration of a main part of a vibration actuator according to a second modified example. 11 is a cross-sectional view taken along line CC of FIG. 10. FIG. 1 is a diagram showing a game device as an example of an electronic device incorporating a vibration actuator. FIG. 1 is a diagram showing a portable information terminal as an example of an electronic device incorporating a vibration actuator. FIG. 1 is a diagram showing a wearable terminal as an example of an electronic device incorporating a vibration actuator.

The following describes in detail the embodiments of the present invention with reference to the drawings.

[Overall configuration of vibration actuator 1]
Fig. 1 is an external perspective view showing a vibration actuator according to an embodiment of the present invention. Fig. 2 is a perspective view showing the vibration actuator with its cover removed. Fig. 3 is an exploded view showing a fixed body and a movable body in the vibration actuator, and Fig. 4 is an overall exploded perspective view of the vibration actuator.

In this embodiment, the description will be given using a Cartesian coordinate system (X, Y, Z). The figures described later (including the figures used to describe Modifications 1 and 2) also use the same Cartesian coordinate system (X, Y, Z). In the following, the width, depth, and height of the vibration actuator 1 are the lengths in the X, Y, and Z directions, respectively. For convenience, the vibration actuator of this embodiment will be described in Figs. 1 to 4 with the X direction facing horizontally, as the vibration direction. In addition, the "axis of the movable body" in this embodiment means the Y direction centered on the movable body, and in this embodiment, this is the same axis as the central axis of the coil. Note that the X direction and the negative X direction may be both sides, the positive Z direction may be the upper side, and the negative Z direction may be the lower side.

As shown in Figures 1 to 4, the vibration actuator 1 includes a movable body 10, a shaft portion 50, and a fixed body 20. The movable body 10 is supported by the fixed body 20 via the shaft portion 50.

The movable body 10 is supported by the fixed body 20 so that it can rotate freely, with the shaft portion 50 inserted at one end as a fulcrum and the other end moving back and forth. The vibration actuator 1 has a weight portion 80 as part of the part that constitutes the main body of the movable body 10. The weight portion 80 is provided in a part that is cut out of the part that constitutes the main body of the core 14 so that it does not slip out.

The vibration actuator 1 is implemented as a vibration generating source in electronic devices such as game machines GC, smartphones SP, and wearable terminals W (see Figs. 12 to 14), and realizes the vibration function of the electronic device by the reciprocating rotational movement of the movable body 10. The vibration actuator 1 is activated, for example, to vibrate to give the user a sense of operation or realism, or to notify the user of an incoming call.

The vibration actuator 1 is mounted, for example, in an electronic device so that the vibration transmission surface that comes into contact with the user is parallel to the XY plane. In the case of a game controller, for example, the vibration transmission surface is the surface that comes into contact with the body surface of the user's finger or the like, and in the case of a smartphone or tablet device, it is the touch panel surface. In addition, in the case of a wearable device that is attached to the user's clothing or arm, the sliding transmission surface is the outer surface that comes into contact with the clothing or arm (the inner surface 208 shown in FIG. 14).

In the vibration actuator 1, the movable body 10 has a coil 12 and a core 14 around which the coil 12 is wound, and the fixed body 20 has magnets (a first magnet 30 and a second magnet 40).

The movable body 10 is supported movably relative to the fixed body 20 by a magnetic spring formed by the attractive force of magnets (first magnet 30 and second magnet 40). In this embodiment, the movable body 10 is supported movably around the shaft portion 50 relative to the fixed body 20 by a magnetic spring formed by magnets (first magnet 30 and second magnet 40), coil 12, and core 14.

[Shaft portion 50]
FIG. 5 is a cross-sectional view taken along line AA of FIG.
The shaft portion 50 shown in FIGS. 2 to 5 supports the movable body 10 relative to the fixed body 20 so as to be capable of reciprocating rotational movement about the shaft, that is, so as to be capable of vibrating freely.

The shaft portion 50 may be made of either a non-magnetic material or a magnetic material. In this embodiment, the shaft portion 50 is made of a magnetic material such as SUS420J2.

The shaft portion 50 is installed between the base plate 22, which is arranged facing each other so as to sandwich the movable body 10, and the upper surface 241 of the case 24. A washer 282 attached to the shaft portion 50 is interposed between the upper surface 241 of the case 24 and the movable body 10, and a washer 284 attached to the shaft portion 50 is interposed between the base plate 22 and the movable body 10. These washers 282, 284 allow the shaft portion 50 to support the movable body 10 so that it can smoothly rotate back and forth relative to the fixed body 20.

[Movable body 10]
The movable body 10 has a weight portion 80 on the tip side, and for example, the weight portion 80 is fixed to a part of the movable body main body, and inertia is increased without influencing the magnetic spring constant or torque without causing magnetic flux saturation. The movable body 10 will be specifically described below.

The movable body 10 has a core 14 extending from one end to the other end and constituting the main body of the movable body, and a coil 12 wound around the core 14 via a coil bobbin 18.

The movable body 10 has a bush (bearing) 16, which is a bearing provided at one end of the core 14, and a weight portion 80 provided at the other end (tip side).

The core 14 is a magnetic body that extends in the coil axis direction of the coil 12 and is magnetized when current is passed through the coil 12. The core 14 is disposed between the base plate 22 and the upper surface 241 of the case 24 at a predetermined distance from each of them. Here, the predetermined distance is the space that constitutes the movable range of the movable body 10. The core 14 is disposed to extend in the winding axis direction of the wound coil 12. One end 142 and the other end 144 of the core 14 protrude from both sides of the coil 12.

The core 14 may be a ferrite core. The core 14 may also be made of electromagnetic stainless steel, sintered material, MIM (metal injection molding) material, laminated steel sheet, electrolytic galvanized steel sheet (SECC, specific gravity 7.85), etc.

The core 14 is provided extending in a direction perpendicular to the axial direction of the shaft portion 50. The bush 16 is fitted into a through hole formed on one end of the core 14, and the core 14 rotates via the shaft portion 50 inserted into this bush 16. The core 14 vibrates with the other end as the free end in a direction perpendicular to the direction in which the base plate 22 and the upper surface portion 241 of the case 24, which are the fixed body 20, extend, in the X direction here.

The core 14 is arranged in the following order from one end 142 toward the other end (tip side): shaft portion 50, coil 12, and other end 144, which constitutes the free end.

The bush 16 provided on one end 142 side of the core 14 is cylindrical and allows the movable body 10 to rotate around the shaft portion 50 through which it is inserted, and may be made of any material, such as metal such as sintered metal, resin, etc. If the shaft portion 50 is magnetic, the bush 16 is preferably made of a non-magnetic material. Also, if the shaft portion 50 is non-magnetic, the bush 16 may be made of a magnetic material. In this way, if either the shaft portion 50 or the bush 16 is non-magnetic, the magnetic flux passing through the core 14 does not pass between the shaft portion 50 and the bush 16, and there is no increase in friction between the two due to the generation of magnetic attraction.

In other words, friction caused by magnetic attraction is not generated between the bush 16 and the shaft portion 50 through which the bush 16 is inserted, and the movable body 10 can be rotated smoothly. For example, the vibration actuator 1 may be formed by using a durable magnetic shaft (e.g., SUS420J2) for the shaft portion 50 and using a copper-based sintered bearing for the bush 16. This makes it possible to suppress unnecessary magnetic attraction when driving the movable body 10 and to hold the movable body 10 with low friction. In other words, wear caused by driving the movable body 10 is suppressed, and a highly reliable vibration actuator 1 can be realized.

In addition, one end 152 of the flexible substrate 15 is fixed to one end 142 of the core 14, and both ends of the coil 12 are connected to the circuit of the flexible substrate 15.

The flexible substrate 15 supplies power to the coil 12, and in this embodiment is arranged to connect the movable body 10 and the fixed body 20.

The flexible substrate 15 has one end 152 connected to the coil 12 of the movable body 10, the other end 154 fixed to the fixed body 20, and at least one flexible curved portion 156 between the one end 152 and the other end 154, which is conductive from the one end side to the coil 12. The curved portion 156 is interposed between the one end 152 and the other end 154 and has the flexibility to deform in response to the vibration of the movable body 10. The curved portion 156 flexes in a direction perpendicular to the axial direction of the shaft portion 50.

The coil 12 is a coil that moves the movable body 10 when electricity is passed through it, and magnetizes the core 14 when electricity is passed through it, and in particular, one end 142 and the other end 144 are magnetized to become magnetic poles. The coil 12 changes the polarity of both ends of the core 14 (one end 142 and the other end 144) when the direction of current flow is switched.

Between one end 142 and the other end 144 of the core 14 is a core core portion 146 that connects one end 142 and the other end 144 of the core 14. This core core portion 146 is a portion with an outer shape smaller than the outer shapes of the one end 142 and the other end 144, and the coil bobbin 18 (bobbin segments 181, 182) around which the coil 12 is wound is fitted on the exterior of this core core portion 146.

The coil bobbin 18 is composed of bobbin segments 181 and 182. Each of the bobbin segments 181 and 182 is fixed to the core core portion 146 so as to surround the core core portion 146 in the circumferential direction. The bobbin segments 181 and 182 may be composed of a resin material such as polyamide resin, liquid crystal polymer, polyphenylene sulfide resin (PPS resin), etc.

By winding the coil 12 around the core 14 via the coil bobbin 18, the movable body 10 has a rectangular parallelepiped shape whose opposing width decreases from the one end 142 side to the other end 144 side. The winding axis of the coil 12 is the coil axis, which is also the central axis of the core core portion 146. The winding axis direction of the coil 12 is the coil axis direction, which is the extension direction of the core 14.

When the coil 12 is energized and excited, the center of the length in the vibration direction (X direction) of the end faces 142a, 144a (see Figure 5) located in the axial direction of the coil 12 at the base end and tip end of the core 14, i.e., one end 142 and the other end 144, becomes the center of the magnetic pole.

In the movable body 10, the center of the magnetic pole of the movable body 10 is located on the coil axis of the coil 12, at the center of the core core portion 146.

The other end 144 has a shape in which the tip side of the core core portion 146 of the core 14 protrudes in the radial direction around the axis of the core core portion 146. The other end 144 is provided with a weight portion 80.

Figure 6 is a diagram for explaining the movable body, Figure 6A is a longitudinal cross-sectional view of the movable body for explaining the movable body, and Figure 6B is a cross-sectional view taken along line B-B in Figure 3.

As shown in Figures 4 to 6, the other end 144 has a cutout portion 148 formed by cutting out a portion of the core 14. The weight portion 80 is attached to the cutout portion 148, which may be a groove or a hole.

The cutout portion 148 is formed in a concave shape with two openings in a direction parallel to the extension direction of the shaft portion 50, and the weight portion 80 is attached to fill the concave shape. The cutout portion 148 allows the core 14, here the other end portion 144, to have an extension core portion 147 that is the center of the other end portion 144, includes the axis of the core 14, and is continuous with the core core portion 146.

The notch 148 is provided at the other end 144 so that the head 149 constituting the free end has a thickness L2 in the extension direction of the core 14 so as not to become magnetically saturated. Also, at the other end 144, the thickness L1 of the extension core 147, which is the portion sandwiched between the weight portion 80 and is an extension of the core core portion 146, has a constant ratio of thickness to the overall thickness of the other end 144. The notch 148 is provided at the other end 144 of the core 14 so that the cross section of the extension core 147 extending in the extension direction of the core 14 has a constant ratio of area. This configuration prevents deterioration of the magnetic properties and reduction in magnetic flux.

In the core 14, the weight portion 80 is fixed in a concave cutout portion 148 so that it will not come off the core 14 even if centrifugal force is generated by the rotation of the movable body 10, i.e., the core 14. For example, the other end portion 144 of the core 14 may clamp the weight portion 80 within the cutout portion 148, or the weight portion 80 may be fixed by pressing it into the cutout portion 148, or it may be fixed by adhesion, welding, etc.

The notch 148 is formed to correspond to the shape of the weight portion 80, making it even more difficult for the weight portion 80 to come off the other end 144. In this embodiment, it is formed in a box shape, and the weight portion 80 is formed in a corresponding rectangular parallelepiped shape.

The weight section 80 adjusts the weight of the movable body 10 and is made of a high specific gravity material. The weight section 80 is preferably made of a material (e.g., specific gravity of about 16 to 19) that is at least twice as high as the material used for the core 14, such as electrolytic galvanized steel sheet (SECC, specific gravity of 7.85), and tungsten can be used, for example. This makes it possible to increase the mass of the movable body 10 relatively easily, even when the external dimensions of the movable body 10 are set in the design, and to achieve the desired vibration output without influencing the magnetic spring constant and torque without magnetic flux saturation.

[Fixed body 20]
The fixed body 20 rotatably supports the movable body 10 via the shaft portion 50 .
In addition to the magnets (the first magnet 30 and the second magnet 40), the fixed body 20 includes a base plate 22 and a case 24. The fixed body 20 further includes a buffer portion (cushion material) 60.

The base plate 22 is formed from a plate-shaped material such as a steel plate (a rectangular plate in this embodiment). In this embodiment, the base plate 22 constitutes one side (here, the bottom surface) of the vibration actuator 1.

The case 24 is attached to cover the base plate 22, and together with the case 24, the base plate 22 constitutes a housing that movably houses the movable body 10. In this embodiment, the housing is formed in a hollow rectangular parallelepiped shape. A shaft portion 50 is fixed to one end side of the housing in the longitudinal direction along a direction perpendicular to the vibration direction of the movable body 10. The top surface portion 241 of the case 24 constitutes the other side surface that faces one side surface of the vibration actuator 1.

A shaft portion 50 is erected on one end of the base plate 22 via a shaft fixing portion 23. The movable body 10 is arranged on the base plate 22 facing each other at a distance. A first magnet 30 is arranged on one end of the base plate 22 facing one end face of one end 142 of the movable body 10, and a second magnet 40 is arranged on the other end of the base plate 22 facing the end face (tip face) of the other end 144 of the movable body 10. Note that, although the first magnet 30 is included in the configuration in this embodiment, the first magnet 30 may be omitted and only the second magnet 40 may be included.

The case 24 is fixed to the base plate 22 so as to cover the movable body 10 facing the base plate 22 .
In the case 24, the other end of the shaft portion 50 is fixed to an upper surface portion 241 that faces the base plate 22 in terms of height (Z direction) via a shaft fixing portion (not shown).

The case 24 is formed in a box shape (a square box shape in this embodiment) that opens on the side of the base plate 22. In the case 24, an axis portion 50 is installed between the upper surface portion 241 and the base plate 22. The case 24 has two side surface portions 242, 243 that are arranged opposite to each other and spaced apart in the vibration direction of the movable body 10, for example, the width direction (X direction), and one end surface portion 244 and the other end surface portion 245 that are spaced apart in the extension direction of the movable body 10 (here, the depth direction (Y direction)).

The dimensions of the housing formed by attaching the case 24 to the base plate 22 are not particularly limited, but in this embodiment, it is configured to have a rectangular parallelepiped shape with the depth being the longest of the width (X direction), depth (Y direction), and height (Z direction).

The case 24, together with the base plate 22, may be formed from a conductive material, for example, a plate-shaped material such as a steel plate (a rectangular plate in this embodiment). This allows the base plate 22 and the case 24 to function as an electromagnetic shield.

In addition, on the other end side of each of the two side portions 242, 243 of the case 24, a buffer portion 60 (cushion material 61, 62) is provided, with which the free end side of the vibrating movable body 10 comes into contact.

When the movable body 10 vibrates, the other end 144 of the movable body 10 comes into contact with the buffer unit 60, thereby transmitting the vibration of the movable body 10 to the housing of the vibration actuator 1 (see FIG. 8). This allows the buffer unit 60 to generate large vibrations in the housing.

The buffer section 60 is formed of a soft material such as elastomer, rubber such as silicone rubber, resin, or porous elastic body (e.g., sponge). In this embodiment, the buffer section 60 is cushion material 61, 62 provided on both side sections 242, 243 on the housing side. The buffer section 60 may be provided on the movable body 10 side, for example, the other end 144 which is the free end of the movable body 10, so that the movable body 10 contacts both side sections 242, 243 with the buffer section 60 when the movable body 10 vibrates. When the buffer section 60 is an elastomer, the generation of sound or vibration noise when the other end 144 of the core 14 of the movable body 10 contacts the side sections 242, 243 when the movable body 10 is driven can be reduced.

Furthermore, when the buffer section 60 is made of silicone rubber, it is possible to reduce the generation of sound or vibration noise when the other end 144 of the core 14 of the movable body 10 comes into contact with the side sections 242, 243. In addition, when the buffer section 60 is made of silicone rubber, there is no individual difference in thickness compared to elastomers formed from a sponge-like material containing air bubbles inside. Therefore, the thickness of the buffer section 60 can be easily controlled so that it has the desired thickness, and the stability of the characteristics of the buffer section 60 can be ensured.

The magnets (first magnet 30 and second magnet 40) work in cooperation with the coil 12 to move the movable body 10. The magnets function as a magnetic spring due to the magnetic attraction force to the movable body 10. In this embodiment, the magnets and the core 14 around which the coil 12 is wound form a magnetic spring, which supports the movable body 10 so that it can move freely.

The magnet is disposed so as to face the coil 12 in the axial direction of the coil 12 .
In this embodiment, the magnet has a first magnet 30 that faces one end of the core 14 at a distance in the axial direction of the coil 12, and a second magnet 40 that faces the other end of the core 14 at a distance in the axial direction of the coil 12.

The first magnet 30 and the second magnet 40 are each magnetized toward the core 14 (movable body 10). In this embodiment, the magnetization direction of the first magnet 30 and the second magnet 40 is parallel to the axial direction of the coil 12. The first magnet 30 and the second magnet 40 each have two different magnetic poles aligned in a direction perpendicular to the extension direction of the shaft portion 50 (corresponding to the vibration direction of the movable body 10) on the surface facing the core 14.

The center of the core 14 of the movable body 10 (here, the axis of the coil 12, which corresponds to the center of the magnetic pole when the coil 12 is excited) is positioned opposite the boundary of the magnetic poles, i.e., the position where the magnetic poles switch.

The polarity of the magnetic poles of both the first magnet 30 and the second magnet 40 is magnetized so that the torque generated by exciting the coil 12 of the movable body 10 occurs in the same rotational direction of the movable body 10.

For example, as shown in Figs. 5 and 6, in the first magnet 30 and the second magnet 40, the magnetic poles 301, 401 arranged on the side surface portion 242 side and facing the movable body 10 are formed to be the same pole (S pole in Fig. 5). In addition, in the first magnet 30 and the second magnet 40, the magnetic poles 302, 402 arranged on the side surface portion 243 side and facing the movable body 10 are formed to be the same pole (N pole in Fig. 5).

A back yoke 32 is attached to the back surface of the first magnet 30, and a back yoke 42 is attached to the back surface of the second magnet 40, improving the magnetic attraction force of each magnet 30, 40.

For example, the first magnet 30 and the second magnet 40 are magnetized so that the side surface 242 side has an S pole and the side surface 243 side has an N pole. In this case, when the coil 12 is not energized, the first and second magnets 30, 40 each generate a magnetic flux that emanates from the N pole and enters the S pole, as shown in FIG. 5. When not energized, one end 142 of the core 14 around which the coil 12 is wound is attracted to both the S pole and the N pole of the first magnet 30 and is held at a switching position of different magnetic poles 301, 302 (S pole and N pole). In addition, the other end 144 of the core 14 is attracted to both the S pole and the N pole of the second magnet 40 and is held at a switching position of different magnetic poles 401, 402 (S pole and N pole). The first magnet 30 and the second magnet 40, together with the core 14, which is the magnetic body of the movable body 10, function as a magnetic spring due to the magnetic attraction force generated between them and the core 14, and support the movable body 10 so that it can move freely.

The other end 154 of the flexible substrate 15, which is connected to the coil 12 at one end 152, is fixed to the side portion 243.

The flexible substrate 15 has one end 152 connected to the coil 12 fixed to one end of the movable body 10, and the other end 154 fixed to the fixed body 20, in this case, the side surface 243. The other end 154 is fixed to the side surface 243 with a portion exposed to the outer surface of the housing. When the movable body 10 is in motion, the vicinity of the shaft 50 has a smaller range of motion than the other end of the movable body 10. As a result, the load applied to the curved portion 156 of the flexible substrate 15 disposed near the shaft 50 is smaller. In this way, since the flexible substrate 15 is fixed near the shaft 50, the displacement of the flexible substrate 15 can be minimized, and breakage due to stress generated during movement can be prevented.

In addition, in the flexible substrate 15, an elastic member such as an elastic adhesive or an elastic adhesive tape may be interposed between the one end 152 and the movable body 10 so that the elastic member absorbs the impact during vibration.

[Magnetic circuit of vibration actuator 1]
FIG. 7 is a diagram showing the magnetic circuit of the vibration actuator, and shows the vibration actuator 1 as viewed from the positive side (upper side) in the Z direction to the negative side (lower side) in the Z direction. FIGS. 8A to 8C are longitudinal cross-sectional views showing the operation of the movable body, and show the vibration actuator 1 as viewed from the positive side (upper side) in the Z direction to the negative side (lower side) in the Z direction. FIG. 8A shows the state of the movable body 10 when it is not energized (reference state). FIG. 8B shows the state of the movable body 10 when the coil 12 is energized clockwise when the vibration actuator 1 is viewed from the tip side of the movable body 10, that is, the other end 144 side of the core 14. FIG. 8C shows the state of the movable body 10 when the coil 12 is energized counterclockwise when the vibration actuator 1 is viewed from the tip side of the movable body 10, that is, the other end 144 side of the core 14.

In the vibration actuator 1, the movable body 10 is disposed between the base plate 22 and the case 24 of the fixed body 20 with one end supported via the shaft 50. In addition, the magnets (first magnet 30 and second magnet 40) are disposed in the axial direction of the coil 12 of the movable body 10, facing both ends (one end 142, the other end 144) of the core 14 around which the coil 12 is wound, with two different magnetic poles facing the coil 12 side. The magnetic pole 301 of the first magnet 30 and the magnetic pole 401 of the second magnet 40 are of the same polarity, and the magnetic pole 302 of the first magnet 30 and the magnetic pole 402 of the second magnet 40 are of the same polarity.

In each of the first magnet 30 and the second magnet 40, the two different magnetic poles 301, 302, 401, 402 are arranged side by side in the vibration direction (X direction) perpendicular to the axial direction of the shaft portion 50.

When electricity is applied to the coil 12 from a power supply unit (e.g., the drive control unit 203 shown in Figures 12 to 14) via the flexible substrate 15, the movable body 10 reciprocates in the X direction, that is, in the direction of approaching and moving away from the side portions 242 and 243 of the case 24.

Specifically, the other end of the movable body 10 oscillates. As a result, the vibration output of the vibration actuator 1 is transmitted to the user of the electronic device having the vibration actuator 1.

In the vibration actuator 1, a magnetic circuit as shown in Figure 7 is formed.

In the vibration actuator 1, when no current is applied to the coil 12, that is, in the reference state, both ends (one end 142, the other end 144) of the core 14 around which the coil 12 is wound are attracted to the first magnet 30 and the second magnet 40, respectively.

The center of the length (length in the vibration direction) perpendicular to the axial direction of each of the two ends (one end 142, the other end 144) of the core 14 is located at a position facing the switching position of the magnetic poles of the magnet. The center of the length (length in the vibration direction) perpendicular to the axial direction of each of the two ends (one end 142, the other end 144) is located on the same axis as the axis of the coil 12.

Specifically, one end 142 of the core 14 is attracted by the magnetic attraction forces of both of the different magnetic poles 301, 302 of the first magnet 30, and is held at the switching position of the magnetic poles 301, 302.

The other end (free end) 144 of the core 14 is attracted by the magnetic attraction forces of the two different magnetic poles 401, 402 of the second magnet 40, and is held at the switching position of the magnetic poles 401, 402.

In this way, the movable body 10 is held in the reference state by only the magnetic spring formed by the first magnet 30 and the second magnet 40 of the fixed body 20.

In the vibration actuator 1, the coil 12 is arranged along the magnetic flux from the first magnet 30 and the second magnet 40, but at a distance from it.

With this configuration, when electricity is applied as shown in Figures 7 and 8B, the current flowing through the coil 12 magnetizes both ends of the core 14 (one end 142, the other end 144) to different magnetic poles. Specifically, the one end 142 is magnetized to a north pole and the other end 144 is magnetized to a south pole.

As a result, one end 142 is attracted to the magnetic pole 301 of the first magnet 30 and repels the magnetic pole 302 of the first magnet 30, generating a thrust f, and moving in the direction of thrust f. On the other hand, the other end 144 repels the magnetic pole 401 of the second magnet 40 and is attracted to the magnetic pole 402 of the second magnet 40, moving in the thrust -F direction.

As shown in FIG. 8B, when electricity is applied to the coil 12, in the vibration actuator 1, both ends (one end 142, the other end 144) located on either side of the shaft portion 50 move in the thrust f and -F directions, respectively, generating a thrust -M in the same rotational direction. As a result, the movable body 10 rotates around the shaft portion 50 in the thrust -M direction, and the other end 144 of the movable body 10 moves toward the side portion 243 and comes into contact (specifically collides) with the side portion 243, i.e., the housing, via the cushion material 62, imparting vibration to the housing.

When the current direction of the coil 12 is switched to the opposite direction and current is applied as shown in FIG. 8C, thrusts -f and F in the opposite directions are generated. Specifically, one end 142 is magnetized as an S pole and the other end 144 is magnetized as an N pole. As a result, one end 142 repels the magnetic pole 301 of the first magnet 30 and is attracted to the magnetic pole 302 of the first magnet 30, generating thrust -f and moving in the thrust -f direction. On the other hand, the other end 144 is attracted to the magnetic pole 401 of the second magnet 40 and repels the magnetic pole 402 of the second magnet 40, moving in the F direction.

As shown in FIG. 8C, when electricity is applied to the coil 12, in the vibration actuator 1, both ends (one end 142, the other end 144) located on either side of the shaft portion 50 move in the thrust -f and F directions, respectively, generating a thrust M in the same rotational direction. As a result, the movable body 10 rotates around the shaft portion 50 in the thrust M direction, and the other end 144 of the movable body 10 moves to the side of the side portion 242 opposite the side portion 243, and comes into contact (specifically collides) with the side portion 242, i.e., the housing, via the cushion material 61, imparting vibration to the housing.

In the vibration actuator 1, the movable body 10 is supported so as to be capable of reciprocating and rotating with respect to the fixed body 20 around the shaft portion 50, using only a magnetic spring that uses a magnet (at least the second magnet 40) and a core 14, without using any elastic member such as a leaf spring.

Therefore, unlike conventional vibration actuators that use metal springs to support a movable body so that it can vibrate freely, this prevents metal fatigue and damage due to impact, which are defects specific to metal springs.

The shaft portion 50 supports the movable body 10 at one end 142 of the core 14 of the movable body 10 so that it can swing freely, and a weight portion 80 made of a high specific gravity material is attached to a cutout portion 148 formed by cutting out a portion of the other end 144 of the core 14. The weight portion 80 is provided in the cutout portion 148 so that movement in the vibration direction within the cutout portion 148 is restricted. As a result, the weight portion 80 is provided on the movable body 10 as part of the core 14 that constitutes the main body of the movable body, and is the entire length of the swinging movable body 10 while being surrounded on all four sides, which is the direction of movement during the reciprocating rotational movement of the movable body 10.

In other words, the mass of the tip (other end) of the movable body 10 can be increased so that it does not come off the movable body 10 without changing the size of the movable body 10. This allows the vibration actuator 1 to increase inertia without lowering the resonance point while maintaining the magnetic characteristics.

In addition, in this embodiment, the magnets are arranged on both sides of the core 14 as the first magnet 30 and the second magnet 40. The two magnetic poles 301, 302, 401, 402 are arranged so that the torque generated at each end 142, 144 of the movable body 10 occurs in the same rotational direction. At both ends of the core 14 (one end 142, the other end 144), a magnetic attraction force is generated between the first magnet 30 and the second magnet 40, attracting each other.

As a result, when the movable body 10 is moved by cooperation between the first magnet 30, the second magnet 40 and the coil 12, the load caused by the magnetic attraction force acting on the shaft portion 50 is offset, thereby reducing the load on the shaft portion 50 and the bushing 16.

In addition, since the movable body 10 contacts the side portions 242, 243 of the housing inside the housing (a state equivalent to a contact state), vibrations can be transmitted directly to the vibration actuator housing, and large vibrations can be generated from the vibration actuator 1 itself. In addition, since the movable body 10 contacts the fixed body 20 (housing) when it vibrates, the amount of vibration is constant, and a stable vibration output can be achieved as the vibration actuator 1.

The other end 144 of the core 14, which is the free end of the movable body 10, is formed so that its thickness in the X direction decreases toward the free end. This makes it possible to increase the range of motion of the movable body 10 when the other end 144 swings and contacts the cushioning materials 61, 62, compared to when the other end 144 of the core 14, which is the free end of the movable body 10, has the same thickness in the X direction toward the free end. This allows the vibration actuator 1 to ensure a greater vibration output.

Furthermore, according to the vibration actuator 1, a buffer section 60 is provided on the inner wall surface (side surface sections 242, 243) of the case 24, and contacts the movable body 10 via the buffer section 60 (cushioning material 61, 62). The buffer section 60 absorbs the impact when the movable body 10 vibrates and contacts the base plate 22 or the case 24, and can transmit vibrations to the user while reducing the generation of contact sounds and vibration noise. Furthermore, each time it vibrates, the movable body 10 alternately contacts (specifically collides with) the base plate 22 and the case 24 via the buffer section 60, amplifying the vibration output. This allows the user to experience a vibration output that is greater than the vibration output of the actual movable body 10.

The vibration actuator 1 is driven by an AC wave input from a power supply unit (for example, the drive control unit 203 shown in Figures 12 to 14) to the coil 12 via the flexible substrate 15. In other words, the direction of current flow in the coil 12 switches periodically, and a thrust M on the positive side of the X direction and a thrust -M on the negative side of the X direction act alternately on the movable body 10. This causes the other end of the movable body 10 to vibrate in an arc in the XY plane.

Below is a brief explanation of the driving principle of the vibration actuator 1. In the vibration actuator 1 of this embodiment, if the moment of inertia of the movable body 10 is J [kg· ^m2 ] and the spring constant of the magnetic spring in the torsional direction is _Ksp , the movable body 10 vibrates with respect to the fixed body 20 at a resonance frequency f _r [Hz] calculated by the following formula (1).

Since the movable body 10 constitutes a mass part in a vibration model of a spring-mass system, the movable body 10 enters a resonant state when an AC wave having a frequency equal to the resonant frequency f _r of the movable body 10 is input to the coil 12. In other words, the movable body 10 can be vibrated efficiently by inputting an AC wave having a frequency approximately equal to the resonant frequency f _r of the movable body 10 from a power supply unit (for example, the drive control unit 203 shown in FIGS. 12 to 14) to the coil 12.

The equation of motion and the circuit equation showing the driving principle of the vibration actuator 1 are shown below. The vibration actuator 1 is driven based on the equation of motion shown in the following equation (2) and the circuit equation shown in the following equation (3).

That is, the moment of inertia J [kg· ^m2 ], rotation angle 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)], etc. of the movable body 10 in the vibration actuator 1 can be appropriately changed within a range that satisfies formula (2). In addition, the voltage e(t) [V], resistance R [Ω], inductance L [H], and back electromotive force constant _Ke [V/(rad/s)] can be appropriately changed within a range that satisfies formula (3).

In this way, with the vibration actuator 1, when current is applied to the coil 12 with an AC wave corresponding to the resonant frequency f _r determined by the moment of inertia J of the movable body 10 and the spring constant K _sp of the magnetic spring, it is possible to efficiently obtain a large vibration output.

<Modification 1>
Fig. 9 is a cross-sectional view showing a main configuration of a first modified example of a movable body in the vibration actuator of the present embodiment 1. In detail, Fig. 9A is a longitudinal cross-sectional view of a movable body provided for explaining the first modified example of the movable body, and Fig. 9B is a cross-sectional view of the other end of the core of the first modified example of the vibration actuator, showing a portion similar to the portion shown in the cross section along line B-B in Fig. 3.

The movable body 10A of the vibration actuator of modified example 1 shown in FIG. 9 differs from the movable body of the vibration actuator 1 in that the shape of the weight portion 80A provided at the other end (tip portion) 144A of the core 14A has been changed.

That is, in the movable body 10A, in the configuration of the vibration actuator 1, the shape of the notch portion 148A provided in the other end portion 144A of the core 14A is a through hole that penetrates in the Z direction, and the weight portion 80A is attached inside the through hole.

The movable body 10A of variant example 1 in Figure 9 has a core 14A having a structural configuration similar to that of the core 14, and a bushing 16 into which the shaft portion 50 (see Figure 2) is inserted is inserted on one end 142A side of this core 14A, and a weight portion 80A is provided on the other end 144A side.
The coil 12 is wound around the outer periphery of the core portion 146A between the one end portion 142A and the other end portion 144A via a coil bobbin 18.

The cutout portion 148A provided in the other end portion 144A is a through hole formed penetrating in a direction (Z direction) perpendicular to both the vibration direction and the extension direction of the core 14A.
The weight portion 80A is fixed within the through hole (notch portion 148A) so that the center of gravity is located on the axis of the core portion 146A.
As a result, movable body 10A can achieve the same effects as movable body 10 having weight portion 80 of the first embodiment.

Figure 10 is a partially exploded perspective view showing the main configuration of the vibration actuator variation 2, and Figure 11 is a cross-sectional view taken along line CC in Figure 10.

The movable body 10B of the modified example 2 shown in FIG. 10 is different from the movable body 10 of the vibration actuator 1 in the shape of the weight portion 80B and the shape of the corresponding tip portion 144B of the core 14B. That is, in the movable body 10B, the weight portion 80B is composed of divided bodies 81B and 82B.

The segments 81B and 82B are formed to surround the extension core 147B, and are each made of a high specific gravity material such as tungsten.

The extension core portion 147B is disposed on the core 14B on an extension of the core core portion 146B around which the coil 12 is wound, and is formed continuously with the core core portion 146B.
The outer periphery of the core portion 146B is surrounded by a bobbin 18B formed by combining bobbin segments 184, 185 that are separated in the width direction. The coil 12 is wound around this bobbin 18B.

The extension core portion 147B is provided together with a notch portion 148B in a portion of the other end portion 144B, among the one end portion 142B, the core core portion 146B, and the other end portion 144B, which are continuous in the longitudinal direction of the core 14B.

The extension core portion 147B, together with the notch portion 148B and the head portion 149B, which is the free end, constitutes the other end portion 144B of the core 14B. At the other end portion 144B, it can be said that the weight portion 80B is attached within the notch portion 148B.

The divided bodies 81B and 82B are formed to have a U-shaped or L-shaped cross section. If the divided bodies 81B and 82B have the same shape, the manufacturing cost of the weight portion 80B can be reduced.
The divided bodies 81B and 82 are attached so as to sandwich the extension core portion 147B and surround the extension core portion 147B.

The divided bodies 81B and 82B are fixed to the extension core 147B by press-fitting or adhesive. The divided bodies 81B and 82B are arranged in the concave portion on the core 14B between the portion where the coil 12 is wound and the head 149B, and are arranged so as to surround the extension core 147B. This makes them less likely to come off even if centrifugal force is generated by the rotation of the movable body 10B.

The weight portion 80B consisting of the divided bodies 81B and 82B is formed so that the length in the width direction, i.e., the vibration direction, of the weight portion 80B gradually decreases toward the free end side, i.e., toward the head portion 149B. As a result, the width direction length of the other end portion 144B consisting of the weight portion 80B and the head portion 149B also decreases in the width direction toward the free end side.
As a result, movable body 10B can achieve the same effects as movable body 10 having weight portion 80 of the first embodiment.

<Electronic devices incorporating vibration actuators>
Fig. 12 to Fig. 14 are diagrams showing examples of electronic devices incorporating a vibration actuator. Fig. 12 shows an example in which a vibration actuator is incorporated in a game controller GC, Fig. 13 shows an example in which a vibration actuator is incorporated in a smartphone SP as a mobile terminal, and Fig. 14 shows an example in which a vibration actuator is incorporated in a wearable terminal W.

The game controller GC is connected to the game console via wireless communication, for example, and is used by the user by gripping or holding it. Here, the game controller GC has a rectangular plate shape, and the user grasps and operates the left and right sides of the game controller GC with both hands.

The game controller GC notifies the user of commands from the game console by vibration. Although not shown, the game controller GC also has functions other than command notification, such as an input operation unit for the game console.

The smartphone SP is, for example, a mobile communication terminal such as a mobile phone or a smartphone. The smartphone SP notifies the user of an incoming call from an external communication device by vibration, and also realizes each function of the smartphone SP (for example, functions that provide a sense of operation and a sense of realism).

The wearable terminal W is worn by the user. Here, the wearable terminal W has a ring shape and is worn on the user's finger. The wearable terminal W is connected to an information and communication terminal (e.g., a mobile phone) via wireless communication. The wearable terminal W notifies the user of an incoming call or e-mail on the information and communication terminal by vibration. Note that the wearable terminal W may also have functions other than incoming call notification (e.g., input operations on the information and communication terminal).

As shown in Figures 12 to 14, electronic devices such as a game controller GC, a smartphone SP, and a wearable device W each have a communication unit 201, a processing unit 202, a drive control unit 203, and vibration actuators 100A, 100B, 100C, and 100D that use a vibration actuator 1 (including vibration actuators having movable bodies 10A and 10B) as a drive unit. Note that multiple vibration actuators 100A and 100B are implemented in the game controller GC.

In the game controller GC, smartphone SP, and wearable terminal W, the vibration actuators 100A, 100B, 100C, and 100D are mounted, for example, so that the main surface of the terminal and a surface perpendicular to the vibration direction of the vibration actuator 1, in this case the side portions 242 and 243 of the case 24, are parallel. The main surface of an electronic device is the surface that comes into contact with the user's body surface, and in this embodiment, this means the vibration transmission surface that comes into contact with the user's body surface and transmits vibrations.

Specifically, in the game controller GC, vibration actuators 100A and 100B are mounted so that their vibration direction is perpendicular to the surface that the operating user's fingertips, finger pads, or hand contacts, or the surface on which the operation unit is provided. In the case of a smartphone SP, vibration actuator 100C is mounted so that its vibration direction is perpendicular to the display screen (touch panel surface). In the case of a wearable device W, the inner circumferential surface 208 of the ring-shaped housing is the main surface (vibration transmission surface), and vibration actuator 1 is mounted so that the inner circumferential surface 208 and the XY plane are approximately parallel (including parallel). As a result, vibrations perpendicular to the main surfaces of the game controller GC, smartphone SP, and wearable device W are transmitted to the user.

The communication unit 201 is connected to an external communication device via wireless communication, receives signals from the communication device, and outputs them to the processing unit 202. In the case of a game controller GC, the external communication device is a game console body serving as an information communication terminal, and communication is performed according to a short-range wireless communication standard such as Bluetooth (registered trademark). In the case of a smartphone SP, the external communication device is, for example, a base station, and communication is performed according to a mobile communication standard. In the case of a wearable terminal W, the external communication device is, for example, an information communication terminal such as a mobile phone, smartphone, or portable game terminal, and communication is performed according to a short-range wireless communication standard such as Bluetooth (registered trademark).

The processing unit 202 converts the input signal into a drive signal for driving the vibration actuators 100A, 100B, 100C, and 100D using a conversion circuit unit (not shown), and outputs the drive signal to the drive control unit 203. In the smartphone SP, the processing unit 202 generates drive signals based on signals input from the communication unit 201 as well as signals input from various functional units (not shown, for example, an operation unit such as a touch panel).

The drive control unit 203 is connected to the vibration actuators 100A, 100B, 100C, and 100D, and is equipped with circuits for driving the vibration actuators 100A, 100B, 100C, and 100D. The drive control unit 203 supplies drive signals to the vibration actuators 100A, 100B, 100C, and 100D.

The vibration actuators 100A, 100B, 100C, and 100D are driven in accordance with a drive signal from the drive control unit 203. Specifically, in the vibration actuators 100A, 100B, 100C, and 100D, the movable body 10 vibrates in a direction perpendicular to the main surfaces of the game controller GC, the smartphone SP, and the wearable terminal W.

Each time the movable body 10 vibrates, it comes into contact with the side portions 242, 243 of the case 24 via the cushioning materials 61, 62, so that the impact on the side portions 242, 243 of the case 24 caused by the vibration of the movable body 10, i.e., the impact on the housing, is directly transmitted to the user as vibration. In particular, since the game controller GC is equipped with multiple vibration actuators 100A, 100B, one or both of the multiple vibration actuators 100A, 100B can be driven simultaneously in response to the input drive signal.

Vibrations are transmitted in a direction perpendicular to the surface of the user's body that is in contact with the game controller GC, smartphone SP, and wearable device W, so that the user can be given a sufficient bodily sensation of vibration. In the game controller GC, bodily sensation of vibration can be given to the user by one or both of vibration actuators 100A, 100B, and highly expressive vibrations can be given, such as at least selectively giving strong and weak vibrations.

The invention made by the inventor has been specifically described above based on the embodiment, but the invention is not limited to the above embodiment and can be modified without departing from the gist of the invention.

For example, the vibration actuator according to the present invention is suitable for application to portable devices (e.g., portable information terminals such as tablet PCs, portable game terminals) other than the game controller GC, smartphone SP, and wearable terminal W shown in the embodiment. Furthermore, the vibration actuator 1 of the present embodiment can be used not only in the portable devices described above, but also in electric beauty appliances such as facial massagers that require vibration.

The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

The vibration actuator of the present invention can improve the inertia during operation without increasing the size or affecting the magnetic properties, is small and can provide the user with a vibration that is sufficiently felt, and is useful for installation in electronic devices such as game controllers, smartphones, and wearable devices.

1, 100A, 100B, 100C, 100D Vibration actuator 10, 10A, 10B Movable body 12 Coil 14, 14A, 14B Core 15 Flexible substrate 16 Bush (bearing)
Reference Signs List 18, 18B Bobbin 20 Fixed body 22 Base plate 23 Shaft fixing portion 24 Case 30 First magnet 32, 42 Back yoke 40 Second magnet 50 Shaft portion 60 Buffer portion 61, 62 Cushioning material 80, 80A, 80B Weight portion 81B, 82B Divided body 142, 152 One end portion 144, 154 Other end portion 142a, 144a End surface 146, 146A, 146B Core portion 147, 147B Extension core portion (central shaft portion)
148, 148A, 148B Cutout portion 149, 149B Head portion 156 Curved portion 181, 182, 184, 185 Bobbin division body 201 Communication portion 202 Processing portion 203 Drive control portion 208 Inner peripheral surface 241 Top surface portion 242, 243 Side portion 244 One end surface portion 245 Other end surface portion 282, 284 Washer 301, 302, 401, 402 Magnetic pole

Claims (4)

a movable body including a coil and a core around which the coil is wound, the core extending in a winding axis direction of the coil and having one end and the other end protruding therefrom;
A fixed body having a magnet;
a shaft portion that supports the movable body rotatably relative to the fixed body at one end side of the core;
a vibration actuator having a structure in which the movable body rotates and vibrates reciprocally around the shaft portion relative to the fixed body by cooperation between the coil and the magnet when electricity is applied,
the magnet is disposed opposite at least one of the one end and the other end of the core in an extension direction of the core when not energized, and has two magnetic poles with different polarities aligned in a reciprocating rotational vibration direction,
The core has a notch on the other end side,
A weight portion is fixed to the cutout portion ,
The cutout portion is formed at the other end of the core so as to surround a core portion extending in an extension direction of the core,
The weight portion is composed of a plurality of divided bodies arranged in the cutout portion so as to surround the periphery of the core portion.
Vibration actuator. The cutout portion is provided at the other end of the core such that a cross section of the core portion has a constant ratio of an area in the extension direction of the other end to an entire cross section of the core portion .
The vibration actuator according to claim 1. the notch portion is provided at the other end portion such that the other end portion has a thickness in an extension direction of the core on a free end side of the other end portion,
The vibration actuator according to claim 1 or 2 . Mounting a vibration actuator according to any one of claims 1 to 3 ;
Electronic devices.

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