Vibration actuator

Abstract

To obtain strong vibrations without increasing weight. [Solution] The vibration actuator is a vibration actuator that causes a movable part housed inside a housing and elastically supported by the housing to vibrate elastically by the driving force of a drive unit, the drive unit having a pair of magnets fixed inside the housing so as to face each other across space, and a coil included in the movable part and arranged in space, and generates a driving force by the interaction of the magnetic field from the magnets and the current flowing through the coil, the housing has at least a pair of first leaf springs that elastically support the movable part, the first leaf springs having a connecting part connected to the housing, a pair of arm parts that branch off symmetrically from the connecting part and curve in a meandering shape, a confluence branching part where the pair of arm parts merge and branch off midway between the connecting part and the ends of the pair of arm parts, and a pair of support parts arranged at the ends of the pair of arm parts and supporting the movable part.

Description

Technical Field

[0001] The present invention relates to a vibration actuator.

Background Art

[0002] There is known a vibration actuator in which a movable part is elastically supported by a fixed part and the movable part is elastically vibrated with respect to the fixed part by a magnetic drive circuit including a coil and a magnet (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the vibration actuator as described in Patent Document 1, if the weight of the movable part is increased, strong vibration can be obtained, but the weight of the vibration actuator itself also increases. Therefore, a vibration actuator capable of obtaining strong vibration without increasing the weight is desired.

[0005] An object of the present invention is to provide a vibration actuator capable of obtaining strong vibration without increasing the weight.

Means for Solving the Problems

[0006] The vibration actuator according to the present invention is a vibration actuator that includes a movable part housed inside a housing and elastically supported by the housing, and elastically vibrates the movable part by a driving force of a driving part. The drive unit comprises a pair of magnets fixed inside the housing so as to face each other across space, and a coil included in the movable part and arranged in the space, and generates the driving force through the interaction between the magnetic field of the magnets and the current flowing through the coil. The housing has at least one pair of first leaf springs that elastically support the movable part, The first leaf spring has a connecting portion connected to the housing, a pair of arm portions that branch symmetrically from the connecting portion and curve in a meandering shape, a merging branching portion where the pair of arm portions merge and branch off midway between the connecting portion and the ends of the pair of arm portions, and a pair of support portions arranged at the ends of the pair of arm portions to support the movable portion. [Effects of the Invention]

[0007] According to the present invention, strong vibrations can be obtained without increasing the weight. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view of the external appearance of a vibration actuator according to an embodiment of the present invention. [Figure 2] Figure 1 is an exploded perspective view of the fixed part that constitutes the vibration actuator shown. [Figure 3] Figure 2 is a perspective view of the first housing that constitutes the fixed part shown. [Figure 4] This diagram illustrates the leaf springs in the first housing shown in Figure 3. [Figure 5] Figure 1 is a perspective view of the movable parts that make up the vibration actuator shown. [Figure 6] Figure 5 is an exploded perspective view of the movable part. [Figure 7] This figure shows a magnified view of a part of the vibration actuator shown in Figure 1. [Figure 8] Figure 1 is a diagram illustrating the operation of the vibration actuator shown. [Figure 9] This graph shows the relationship between drive frequency and vibration acceleration for a conventional vibration actuator and the vibration actuator shown in Figure 1. [Figure 10] It is an external perspective view showing a modified example of the vibration actuator shown in FIG. 1. [Figure 11] It is an exploded perspective view of the fixed part constituting the vibration actuator shown in FIG. 10. [Figure 12] It is an exploded perspective view of the movable part constituting the vibration actuator shown in FIG. 10. [Figure 13] In the vibration actuator shown in FIG. 10, it is a diagram showing an example of the connection between the leaf spring of the first housing and the leaf spring of the second housing and the weight. [Figure 14] It is a diagram showing another example of the connection shown in FIG. 13. [Figure 15] It is a diagram showing another example of the connection shown in FIG. 13.

Mode for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0010] In this embodiment, an orthogonal coordinate system (X, Y, Z) will be used for the description. Here, the vibration directions of the movable parts 30A and 30B described later will be described as the X direction. Also, the Z direction may be described as the vertical direction.

[0011] [Vibration Actuator] The vibration actuator 10A according to this embodiment will be described with reference to FIGS. 1 to 9. FIG. 1 is an external perspective view of the vibration actuator 10A.

[0012] The vibration actuator 10A is a box-shaped vibration actuator, and here, as an example, it has a rectangular parallelepiped shape. The vibration actuator 10A vibrates a movable part 30A (see FIG. 5 described later) disposed inside, thereby vibrating a vibration object to which the vibration actuator 10A is attached. When the vibration actuator 10A vibrates the vibration object, for example, vibration is imparted to a person in contact with the vibration object.

[0013] The vibration actuator 10A mainly includes a fixed part 20A, a movable part 30A, and a wiring part 40 (see FIG. 5 described later).

[0014] [Fixed part] The fixed part 20A will be described with reference to FIGS. 2 to 4. FIG. 2 is an exploded perspective view of the fixed part 20A that constitutes the vibration actuator 10A. FIG. 3 is a perspective view of the first housing 21 that constitutes the fixed part 20A. FIG. 4 is a view for explaining the leaf spring 210 of the first housing 21, and is a cross-sectional view taken along the line A-A in FIG. 3.

[0015] The fixed part 20A has a first housing 21 and a second housing 22A (the first member and the second member in the present invention) that form a box-shaped housing for accommodating the movable part 30A inside. The fixed part 20A also has an upper yoke 23, a lower yoke 24A, an upper magnet 25, and a lower magnet 26.

[0016] The first housing 21 and the second housing 22A are an upper box and a lower box obtained by dividing the box-shaped housing in the vertical direction, and are respectively formed by processing a single plate material made of a spring material.

[0017] For example, by performing press processing or edging processing on a single plate material, the shapes of each part (for example, the side surfaces, top surface, bottom surface, leaf spring, etc. described later) that constitute the first housing 21 and the second housing 22A are formed. Then, by performing bending processing or the like on each part formed on the single plate material, and performing joining processing or the like between the parts as necessary, the first housing 21 and the second housing 22A are formed.

[0018] As the spring material for forming the first housing 21 and the second housing 22A, for example, a stainless steel spring material (for example, SUS301 - CSP) or the like is used. This material is an example and can be changed as appropriate.

[0019] The first housing 21 has a pair of side surfaces 21a facing each other in the X direction, a pair of side surfaces 21b facing each other in the Y direction, a top surface 21c, and a pair of leaf springs 210 facing each other in the X direction.

[0020] In a single sheet of material, by bending the leaf spring 210, the portion of the leaf spring 210 before bending forms a single opening consisting of an opening 21d on the top surface 21c side and a side opening 21e on the side surface 21b side. The opening 21d and the side opening 21e serve as openings for welding or bonding work when joining the leaf spring 210 and the weight 33A, which will be described later.

[0021] Furthermore, in the X direction, an end top surface 21f is formed between the side surface 21a and the leaf spring 210. The end top surface 21f secures the displacement range of the leaf spring 210 (the movable part 30A supported by the leaf spring 210).

[0022] Here, as an example, a first housing 21 having a pair of leaf springs 210 is formed from a single sheet of material. In other words, the first housing 21 is an integrated structure with the pair of leaf springs 210. Therefore, the number of parts and assembly steps during manufacturing can be reduced for the first housing 21. In addition, since the sheet material constituting the first housing 21 is made of spring material, the accuracy of the thickness is improved, and the clearance with the movable part 30A (air gap G1 shown in Figure 8) can be secured with high precision.

[0023] Inside the first housing 21 described above, the upper yoke 23 and the upper magnet 25 are attached from top to bottom. The leaf spring 210 of the first housing 21 will be described later with reference to Figures 3 and 4.

[0024] The second housing 22A has a pair of sides 22a facing each other in the X direction, a pair of sides 22b facing each other in the Y direction, and a bottom surface 22c.

[0025] An opening 22d is formed in the bottom surface 22c. Furthermore, a fitting portion (not shown) that fits into the opening 22d is formed on the lower side of the lower yoke 24A. The fitting portion of the lower yoke 24A is fitted into the opening 22d, thereby attaching the lower yoke 24A to the second housing 22A. This configuration allows the lower yoke 24A to be attached to the second housing 22A without increasing its vertical height, thus enabling a thinner vibration actuator 10A.

[0026] By using spring material as the plate material for the second housing 22A, the accuracy of the thickness is improved, and the clearance with the movable part 30A (air gap G2 shown in Figure 8) can be secured with precision.

[0027] Inside the second housing 22A described above, the lower yoke 24A and the lower magnet 26 are attached in order from bottom to top.

[0028] The first housing 21 and the second housing 22A described above are joined together to house the movable part 30A inside, along with the upper yoke 23, lower yoke 24A, upper magnet 25, and lower magnet 26.

[0029] The upper magnet 25 and the lower magnet 26 are arranged to form opposing pairs separated by a space S (see Figure 8 below). As an example, the upper magnet 25 and the lower magnet 26 are each formed by integrating four magnets in a row. Here, as shown in Figure 2, the upper magnet 25 and the lower magnet 26 have upper magnets 25a to 25d and lower magnets 26a to 26d, respectively. In the upper magnets 25a to 25d and the lower magnets 26a to 26d, the opposing poles are in different pairs, and the N poles and S poles are arranged alternately along the X direction.

[0030] The upper magnets 25a to 25d and the lower magnets 26a to 26d are each made by sintering and magnetizing neodymium magnet material powder, for example. However, the upper magnet 25 and the lower magnet 26 are not limited to this configuration; for example, they may each be made by sintering neodymium magnet material powder and magnetizing them into four poles.

[0031] The upper magnet 25 and the lower magnet 26, in the arrangement described above, form a magnetic field (hereinafter referred to as the magnetic field) along the Z direction in space S. The first housing 21 and the second housing 22A are made of non-magnetic spring material, but the upper yoke 23 and the lower yoke 24A are made of magnetic material and are configured to form a magnetic circuit with the upper magnet 25 and the lower magnet 26.

[0032] For the magnetic materials of the upper yoke 23 and lower yoke 24A, for example, silicon steel sheet, electro-galvanized steel sheet (SECC), electromagnetic soft iron, etc., can be used. These magnetic materials are examples and can be changed as appropriate.

[0033] The upper yoke 23 and lower yoke 24A are substantially rectangular plate members, and are formed and positioned to the size necessary to close the opening 21d of the first housing 21 and the opening 22d of the second housing 22A, respectively. By closing the openings 21d and 22d with the upper yoke 23 and lower yoke 24A, it is possible to prevent foreign matter from entering the first housing 21 and the second housing 22A.

[0034] Furthermore, in the upper yoke 23, recessed portions 23a are formed on both ends in the X direction, and the wiring portion 40 is inserted through the recessed portions 23a, so that a drive signal from an external device is supplied to the coil 31, which will be described later.

[0035] As described above, the leaf spring 210 (the first leaf spring in this invention) is made of spring material and is an elastically deformable member. The leaf spring 210 supports the movable part 30A so as to be elastically vibrable relative to the fixed part 20A (first housing 21). In this embodiment, the movable part 30A is configured to vibrate in the X direction (see Figure 8), and the pair of leaf springs 210 are arranged at both ends of the movable part 30A in the X direction.

[0036] The leaf spring 210 has a shape that is symmetrical with respect to the center line Lc, which passes through the center in the Y direction along the Z direction, when viewed from the X direction. The leaf spring 210 has a connecting portion 211, a pair of arm portions 212 and 213, a confluence branching portion 214, and a pair of support portions 215 and 216.

[0037] The connecting portion 211 is the base of the leaf spring 210 and is connected to the end top surface 21f (housing) at the center in the Y direction. The connecting portion 211 is bent from the end top surface 21f at an angle of, for example, 90°. Here, in order for the connecting portion 211 to also function as a spring, it is bent with a radius R of, for example, about three times the thickness of the plate material that makes up the first housing 21.

[0038] The arm sections 212 and 213 branch off symmetrically from the connecting section 211, curve in a meandering shape, and are primarily elastically deformable parts.

[0039] The arm portion 212 has a first arm portion 212a and a second arm portion 212b, separated by a confluence / branching portion 214. The first arm portion 212a has one end connected to a connection portion 211, and in the Y direction, it extends outward from the connection portion 211 in the center of the Y direction, then curves inward, and the other end is connected to the confluence / branching portion 214 in the center of the Y direction, which is spaced apart from the connection portion 211. The second arm portion 212b has one end connected to the confluence / branching portion 214, and in the Y direction, it extends outward from the confluence / branching portion 214 in the center of the Y direction, then curves and extends towards the top surface 21f of the end portion.

[0040] The arm portion 213 has the same configuration as the arm portion 212. Specifically, the arm portion 213 also has a first arm portion 213a and a second arm portion 213b with the confluence branching portion 214 in between. The first arm portion 213a has one end connected to the connection portion 211, and in the Y direction, it extends outward from the connection portion 211 in the center of the Y direction, then curves inward, and the other end is connected to the confluence branching portion 214 in the center of the Y direction, which is spaced apart from the connection portion 211. The second arm portion 213b has one end connected to the confluence branching portion 214, and in the Y direction, it extends outward from the confluence branching portion 214 in the center of the Y direction, then curves and extends towards the top surface 21f of the end.

[0041] As described above, the arm portions 212 and 213 are formed in a meandering shape, which allows the arm portions 212 and 213 to have the desired spring length even if the range of possible placement is limited, thereby enabling the acquisition of desired vibration characteristics.

[0042] The merging and branching section 214 is the part where a pair of arm sections 212 and 213 merge and branch off between the connection section 211 and the ends of the pair of arm sections 212 and 213. The merging and branching section 214 is located at the center in the Y direction, spaced apart from the connection section 211, and extends in the Z direction.

[0043] Since the confluence branch section 214 connects a pair of arm sections 212 and 213, stress can be distributed to the first arm sections 212a and 213a and the second arm sections 212b and 213b, thereby avoiding stress concentration and relieving stress. Furthermore, since the second arm sections 212b and 213b have curved sections 212b1 and 213b1 in the portions adjacent to the confluence branch section 214, stress can be distributed to the second arm sections 212b and 213b, avoiding stress concentration and relieving stress.

[0044] Furthermore, by changing the length in the Z direction and width in the Y direction of the merging branch section 214, the lengths of the arm sections 212 and 213 (first arm sections 212a, 213a and second arm sections 212b, 213b) can be changed, thereby allowing for a change in spring length.

[0045] Support parts 215 and 216 are positioned at the ends of a pair of arm parts 212 and 213 and support the movable part 30A. Here, support parts 215 and 216 are joined to a weight 33A, which will be described later, to support the movable part 30A. Support part 215 is bent at an angle of, for example, 90° from the arm part 212 at the end of the arm part 212. Similarly, support part 216 is bent at an angle of, for example, 90° from the arm part 213 at the end of the arm part 213. Support parts 215 and 216 may be joined to the weight 33A by adhesive or the like, but considering the forces that act due to vibration, it is desirable that they be joined and fixed to the weight 33A by, for example, laser welding.

[0046] The leaf spring 210 having the above-described configuration connects the first housing 21, which functions as a fixed part, and the movable part 30A, and the movable part 30A vibrates in the X direction due to elastic deformation caused by the driving force of the drive unit described later.

[0047] [Movable part] Figure 5 is a perspective view of the movable part 30A that constitutes the vibration actuator 10A. Figure 6 is an exploded perspective view of the movable part 30A. Figure 7 is a magnified view of a part of the vibration actuator 10A.

[0048] As described above, the movable part 30A is elastically vibrable and supported by the first housing 21 via a leaf spring 210. The movable part 30A includes a coil 31, a plate-shaped part 32, a pair of weights 33A, a weight 34, and a wiring part 40.

[0049] The coil 31 is positioned in the space S (see Figure 8) between the upper magnet 25 and the lower magnet 26, which are opposite each other. The windings of the coil 31 are wound perpendicular to the direction of the magnetic field (in this case, the Z direction) in space S. Furthermore, the coil 31 is configured so that the Y direction, which is perpendicular to the X direction of movement, is its longitudinal direction.

[0050] Therefore, the main direction of the current flowing through the coil 31 is the Y direction, which is perpendicular to the direction of the magnetic field (Z direction) (see Figure 8 below). As a result, when current flows through the coil 31, the interaction between the current flowing through the coil 31 and the magnetic field generates a Lorentz force (driving force), which causes the movable part 30A to move in the X direction, as explained in Figure 8 below. With this configuration, the upper magnet 25, the lower magnet 26, and the coil 31 function as a drive unit that drives the movable part 30A.

[0051] As shown in Figures 5 and 6, coil 31 has three coils 31a to 31c corresponding to the upper magnet 25 and lower magnet 26, which are magnetized to four poles. Coils 31a to 31c are arranged in a line of three along the X direction and attached to the plate-shaped part 32. As shown in Figure 8, the lead wires of adjacent coils 31a to 31c are connected so that the direction of current flow is opposite. Furthermore, weights 34a to 34c, which constitute weight 34, are respectively placed in through holes (not shown) in the center of coils 31a to 31c.

[0052] The plate-like portion 32 is a rectangular plate member to which three coils 31a to 31c are attached. Here, as an example, the three coils 31a to 31c are arranged in the X direction on the upper surface of the plate-like portion 32.

[0053] The plate-shaped portion 32 is also positioned in the space S (see Figure 8) between the upper magnet 25 and the lower magnet 26, which are opposite each other. The plate-shaped portion 32 extends in space S in a direction perpendicular to the direction of the magnetic field (in this case, the XY plane direction).

[0054] The plate-like portion 32 is made of a conductive material, and it is preferable that it be made of a material with high conductivity, such as copper, aluminum, or alloys containing these materials.

[0055] As described above, when current flows through the coil 31, the movable part 30A moves in the X direction due to the force it receives from the magnetic field of the magnet, and at this time the plate-shaped part 32 also moves. As the plate-shaped part 32 moves, a change in magnetic flux occurs in the plate-shaped part 32, and eddy currents are generated in the plate-shaped part 32 to counteract this change in magnetic flux. At this time, the eddy currents generate a magnetic field in the same direction as the magnetic field of the magnet on the side in the direction of movement, and a magnetic field in the opposite direction to the magnetic field of the magnet on the side in the opposite direction of movement. The interaction between the magnetic field due to the eddy currents and the magnetic field of the magnet generates a force that acts in the direction that dampens the movement due to the Lorentz force described above, and as a result the movable part 30A is damped. With this configuration, the upper magnet 25, the lower magnet 26 and the plate-shaped part 32 function as dampers that dampen the movable part 30A.

[0056] The plate-like portion 32 has roughly L-shaped openings (not shown). Three openings are formed in this portion. Weights 34a to 34c are inserted and attached to the portions of these openings that extend in the Y direction. The lead wires of the coils 31a to 31c are housed in the portions of these openings that extend in the X direction. By housing the lead wires in these portions, the thickness of the coils 31 and the plate-like portion 32 in the Z direction is kept from increasing.

[0057] Both ends of the plate-shaped portion 32 in the Y direction are fixed to recesses (not shown) formed inside the pair of weights 33A, respectively.

[0058] The pair of weights 33A and 34 are provided to adjust the weight of the movable part 30A.

[0059] Each of the pair of weights 33A is a substantially rectangular parallelepiped member extending in the XZ plane. In the weights 33A, both end faces in the longitudinal direction (X direction) are the molded or fractured surfaces. In this case, since the above end faces of the weights 33A are the molded or fractured surfaces, the surfaces are inclined or rough and are not suitable as fixing surfaces for the member. Therefore, in the weights 33A, the surfaces other than the above end faces, for example, the surfaces on the outside in the Y direction, are stable as fixing surfaces, and mounting portions 33a are recessed at both ends in the X direction of the surfaces on the outside in the Y direction.

[0060] Then, the support parts 215 and 216 of the leaf spring 210 described above are attached to their respective mounting parts 33a. At this time, as shown in Figure 7, the support parts 215 and 216 are attached to the mounting parts 33a by adhesive, laser welding, or the like, using the openings consisting of the opening 21d on the top surface 21c side and the side opening 21e on the side surface 21b side.

[0061] The weight 33A described above is connected to the plate-shaped portion 32 in a way that allows for thermal conductivity. For example, the connection between the weight 33A and the plate-shaped portion 32 is made of a material with high thermal conductivity. The plate-shaped portion 32 generates heat due to eddy currents, but the weight 33A functions as a heat sink, suppressing the temperature rise of the plate-shaped portion 32. In addition, the weight 33A can dissipate not only the heat generated by eddy currents in the plate-shaped portion 32, but also the heat generated by the coils 31a to 31c that are transferred through the plate-shaped portion 32.

[0062] In addition, as will be described later, the plate-shaped portion 32 and the weight 33A vibrate as movable parts 30A, meaning they move through the air, so to speak, they blow air onto the plate-shaped portion 32 and the weight 33A. As a result, the plate-shaped portion 32 and the weight 33A are cooled more than they would be if they were not moving.

[0063] Weight 34 has three weights 34a to 34c corresponding to coils 31a to 31c. As described above, weights 34a to 34c are arranged in through holes in the center of coils 31a to 31c.

[0064] The weight 33A described above is preferably made of a material with high density and high heat dissipation properties, such as tungsten or tungsten alloy. By using a high-density material for the weight 33A, strong vibrations can be obtained without increasing the size of the vibration actuator 10A, making it possible to miniaturize and thin the vibration actuator 10A.

[0065] Furthermore, the weights 34 (weights 34a to 34c) described above may be configured to serve not only as weights but also as core magnetic poles. In that case, the weights 34 (weights 34a to 34c) may be made of a magnetic material.

[0066] The wiring section 40 functions as wiring from an external device that controls the vibration actuator 10A to the coil 31. The wiring section 40 is formed from an FPC (Flexible Printed Circuit). The wiring section 40 has internal connection wiring 41, intermediate wiring 42, and an external connection section 43.

[0067] Two internal connection wires 41 are provided, corresponding to the terminals at both ends of the coil 31. The two internal connection wires 41 are fixed to, for example, the plate-shaped portion 32 and connected to the terminals at both ends of the coil 31, respectively.

[0068] The intermediate wiring 42 connects the internal connection wiring 41 and the external connection section 43, and extends from the internal connection wiring 41 to the external connection section 43. The intermediate wiring 42 is arranged to be pulled out from the inside of the housing to the outside of the housing by passing through the recessed section 23a of the upper yoke 23 described above. The external connection section 43 is connected to an external device.

[0069] Using the wiring section 40 configured as described above, if, for example, an alternating current is supplied to the coil 31 from an external device, the movable part 30A will vibrate in the X direction.

[0070] [Operation of the vibration actuator] The operation of the vibration actuator 10A, specifically the vibration of the movable part 30A, will be explained with reference to Figure 8. Figure 8 is a diagram illustrating the operation of the vibration actuator 10A.

[0071] When coils 31a to 31c are not energized, no current flows through coils 31a to 31c that interacts with the magnetic field formed by the upper magnet 25 and the lower magnet 26. Therefore, the aforementioned driving force is not generated, and the movable part 30A does not move.

[0072] When coils 31a to 31c are energized, current flows through them. Considering the direction of current flow, the currents flowing through coils 31a to 31c are conveniently denoted as currents i1 and i2, as shown in Figure 8. Current i1 flows towards the front of the page, and current i2 flows towards the back of the page.

[0073] The magnetic field formed between the upper magnet 25a and the lower magnet 26a, and between the upper magnet 25c and the lower magnet 26c, is a magnetic field directed upward in the Z direction. In coil 31a, the portion located between the upper magnet 25a and the lower magnet 26a, and in coils 31b and 31c, the portions located between the upper magnet 25c and the lower magnet 26c, are subjected to a current i1 flowing in the direction towards the viewer of the paper. In this case, the interaction between the current i1 and the magnetic field generates a Lorentz force (driving force) in the direction of arrow F, causing the movable part 30A to move in the X direction.

[0074] Similarly, the magnetic fields formed between the upper magnet 25b and the lower magnet 26b, and between the upper magnet 25d and the lower magnet 26d, are magnetic fields directed downward in the Z direction. In coils 31a and 31b, the portion located between the upper magnet 25b and the lower magnet 26b, and in coil 31c, the portion located between the upper magnet 25d and the lower magnet 26d, are subjected to a current i2 flowing in the direction towards the back of the paper. In this case, the interaction between the current i2 and the magnetic fields generates a Lorentz force (driving force) in the direction of arrow F, causing the movable part 30A to move in the X direction.

[0075] In this way, the interaction between the magnetic field formed by the upper magnets 25a-25d and the lower magnets 26a-26d and the current flowing through the coils 31a-31c causes the movable part 30A to move in the X direction in the direction of arrow F.

[0076] When the direction of the current flowing through coils 31a to 31c is reversed, a Lorentz force (driving force) is generated in the opposite direction to arrow F, and the movable part 30A moves in the X direction, opposite to the direction of arrow F. By supplying alternating current to coils 31a to 31c, the direction of the current flowing through coils 31a to 31c changes, causing the movable part 30A to vibrate in the X direction.

[0077] Furthermore, in this embodiment, the movable part 30A has a plate-shaped portion 32 that generates eddy currents in conjunction with vibration (movement), and therefore a braking force also acts to restrain the movable part 30A. The technical effects of this braking force will be explained with reference to Figure 9.

[0078] Figure 9 is a graph showing the relationship between drive frequency and vibration acceleration for a conventional vibration actuator and vibration actuator 10A. In Figure 9, the dashed line shows the relationship between drive frequency and vibration acceleration for the conventional vibration actuator, and the solid line shows the relationship between drive frequency and vibration acceleration for vibration actuator 10A.

[0079] Conventional vibration actuators, as shown in Figure 9, have a peak in vibration acceleration at the resonant frequency F0 of the movable part, and this peak is steep. Therefore, it has been difficult to obtain strong vibrations over a wide frequency range with conventional vibration actuators.

[0080] On the other hand, as described above, the vibration actuator 10A has a movable part 30A which has a plate-shaped part 32 that generates eddy currents in conjunction with vibration (movement). Therefore, a braking force acts to brake the movable part 30A, and this braking force becomes larger near the resonant frequency F0 where the vibration acceleration is large. As a result, as shown in Figure 9, the change in vibration acceleration near the resonant frequency F0 can be made gradual. For example, if the peak of vibration acceleration in the vibration actuator 10A is made the same as the peak of vibration acceleration in a conventional vibration actuator, strong vibration (vibration acceleration) can be obtained over a wide range of drive frequencies.

[0081] As explained above, the vibration actuator 10A has a plate-shaped portion 32 that dampens the vibration of the movable portion 30A by generating eddy currents as the movable portion 30A vibrates (moves). By damping the vibration of the movable portion 30A, the change in vibration acceleration near the resonant frequency F0 can be made gradual, so the vibration actuator 10A can obtain strong vibrations (vibration acceleration) over a wide range of driving frequencies.

[0082] Furthermore, the movable part 30A is supported so as to be able to vibrate elastically by a pair of leaf springs 210 having the above-described configuration. Even when the displacement due to elastic vibration becomes large, the above-described configuration avoids stress concentration and relieves stress, so that the displacement of the leaf springs 210 due to elastic vibration, that is, the range of motion of the vibration of the movable part 30A, can be increased. As a result, the vibration actuator 10A can also increase the vibration acceleration of the movable part 30A, and can obtain strong vibrations.

[0083] Furthermore, since the movable part 30A has a heat-dissipating weight 33A that is heat-conductively connected to the plate-shaped part 32, it is possible to obtain strong vibrations (vibration acceleration) and to dissipate heat generated by eddy currents and coils 31a to 31c.

[0084] <Example 1> Figure 10 is an external perspective view showing a modified example of the vibration actuator 10A, namely the vibration actuator 10B. Figure 11 is an exploded perspective view of the fixed part 20B that constitutes the vibration actuator 10B. Figure 12 is an exploded perspective view of the movable part 30B that constitutes the vibration actuator 10B.

[0085] The vibration actuator 10B, like the vibration actuator 10A, mainly comprises a fixed part 20B, a movable part 30B, and a wiring part 40. The vibration actuator 10B has substantially the same configuration as the vibration actuator 10A described above, but some of its components differ from those of the vibration actuator 10A.

[0086] [Fixed part] In the fixed section 20B, the second housing 22B and the lower yoke 24B differ from the second housing 22A and the lower yoke 24A in the vibration actuator 10A. On the other hand, in the fixed section 20B, the first housing 21, the upper yoke 23, the upper magnet 25, and the lower magnet 26 have the same configuration as in the vibration actuator 10A, so the same reference numerals are used here, and redundant explanations are omitted.

[0087] The second housing 22B differs from the second housing 22A in the vibration actuator 10A, but is basically equivalent in configuration to the first housing 21 in the vibration actuator 10A. The second housing 22B has sides 22a, sides 22b, a top surface, an opening, a side opening 22e, and an end top surface, similar to the sides 21a, sides 21b, top surface 21c, opening 21d, side opening 21e, and end top surface 21f of the first housing 21. Some reference numerals and redundant explanations of some components are omitted here.

[0088] Furthermore, the second housing 22B has a pair of leaf springs 220 (first leaf springs in this invention) equivalent to the leaf springs 210 in the vibration actuator 10A. The pair of leaf springs 220 elastically vibrate the movable part 30B relative to the fixed part 20B (second housing 22B).

[0089] The pair of leaf springs 220 are positioned opposite each other at both ends of the movable part 30B in the X direction, but when assembling the first housing 21 and the second housing 22B, the position of the pair of leaf springs 220 in the X direction is such that they do not come into contact with the leaf springs 210 (see Figure 13 described later).

[0090] The leaf spring 220 has a connecting portion, a pair of arm portions, a confluence / branching portion, and a pair of support portions, similar to the connecting portion 211, a pair of arm portions 212, 213, a confluence / branching portion 214, and a pair of support portions 215, 216 of the leaf spring 210. The pair of support portions of the leaf spring 220 are joined to the weight 33B, which will be described later, to support the movable portion 30B, similar to the pair of support portions 215, 216 of the leaf spring 210.

[0091] In other words, in the vibration actuator 10B, the movable part 30B is supported in a vibratory manner by two pairs of leaf springs 210 and 220. Therefore, even if the displacement due to elastic vibration becomes large, the leaf springs 210 and 220 distribute the stress and relieve it, so that the displacement of the leaf springs 210 and 220 due to elastic vibration, and thus the range of motion of the vibration of the movable part 30B can be increased. As a result, the vibration actuator 10B can also increase the vibration acceleration of the movable part 30B and obtain strong vibrations.

[0092] The lower yoke 24B is different from the lower yoke 24A in the vibration actuator 10A, but has the same configuration as the upper yoke 23 in the vibration actuator 10A. The lower yoke 24B is formed and positioned to the size of closing the opening of the second housing 22B. By closing the opening of the second housing 22B with the lower yoke 24B, it is possible to prevent foreign matter from entering the first housing 21 and the second housing 22A.

[0093] Furthermore, recessed portions 24a are formed on both ends in the X direction, recessed inward in the X direction. A wiring portion 40 can be inserted through the recessed portion 24a, and depending on the arrangement of the vibration actuator 10B, the wiring portion 40 may be inserted through the recessed portion 24a instead of the recessed portion 23a of the upper yoke 23.

[0094] [Movable part] In the movable part 30B, the weight 33B is different from the weight 33A in the vibration actuator 10A. On the other hand, in the movable part 30B, the coil 31, plate-shaped part 32, weight 34, and wiring part 40 have the same configuration as in the vibration actuator 10A, so the same reference numerals are used here, and redundant explanations are omitted.

[0095] The weight 33B has a configuration that is substantially the same as the weight 33A in the vibration actuator 10A, but in this modified example, two pairs of leaf springs 210 and 220 are joined to the weight 33B, so mounting portions 33a are provided corresponding to the two pairs of leaf springs 210 and 220.

[0096] Specifically, the weight 33B has four mounting portions 33a recessed on its outer surface in the Y direction, at both ends in the X direction and at both ends in the Z direction. The support portions 215 and 216 of the leaf spring 210 and the support portion of the leaf spring 220 are attached to the corresponding mounting portions 33a.

[0097] [Example of leaf spring connection 1] Figure 13 shows an example of the connection between the leaf spring 210 of the first housing 21 and the leaf spring 220 of the second housing 22B and the weight 33B in the vibration actuator 10B.

[0098] In the example shown in Figure 13, the support portion of the leaf spring 210 of the first housing 21 (only the support portion 216 is shown in Figure 13) and the support portion of the leaf spring 220 of the second housing 22B (only the support portion 225 is shown in Figure 13) are fixed to the mounting portion 33a of the weight 33B. In this case, the leaf springs 210 and 220 are connected in parallel to support the movable part 30B, and this configuration distributes the stress between the two leaf springs 210 and 220 during vibration, thereby relieving the stress.

[0099] [Example of leaf spring connection 2] Figure 14 shows another example of the connection shown in Figure 13.

[0100] Here, the leaf spring 210 of the first housing 21 has the configuration described above, but the leaf spring 230 (the second leaf spring in this invention) of the second housing 22B has the same configuration as the leaf spring 220, except that it does not have a pair of support parts.

[0101] In the example shown in Figure 14, the leaf springs 210 and 230 are connected to each other by a connecting member 260, such as a spacer or damping material. The support portion of the leaf spring 210 on the first housing 21 (only the support portion 216 is shown in Figure 14) is fixed to the mounting portion 33a of the weight 33B. In this case, the leaf springs 210 and 230 are connected in parallel to support the movable part 30B, and this configuration distributes the stress between the two leaf springs 210 and 230 during vibration, thereby relieving the stress.

[0102] When damping materials such as rubber or resin are used as the connecting member 260, the connecting member 260 functions as a damping mechanism, making it possible to broaden the vibration bandwidth (wideband performance).

[0103] [Example of leaf spring connection 3] Figure 15 shows another example of the connection shown in Figure 13.

[0104] Here, the leaf spring 240 (the second leaf spring in this invention) of the first housing 21 has the same configuration as the leaf spring 210, except that it does not have a pair of support parts. Also, the second housing 22B does not have a leaf spring, but has a separate leaf spring 250 (the third leaf spring in this invention), which has the same configuration as the leaf spring 220, except that it does not have a connecting part.

[0105] In the example shown in Figure 15, the leaf springs 240 and 250 are connected to each other by, for example, the connecting member 260 described above. The support portion of the leaf spring 250 connected to the leaf spring 240 (only the support portion 255 is shown in Figure 15) is fixed to the mounting portion 33a of the weight 33B. In this case, the leaf springs 240 and 250 are connected in series to support the movable part 30B, and this configuration distributes the stress between the two leaf springs 240 and 250 during vibration, thereby relieving the stress.

[0106] <Other variations> In the above embodiment, the movable parts 30A and 30B were described as a moving coil configuration having a coil 31, but the present invention may also be a moving magnet configuration.

[0107] Furthermore, in the above embodiment, the leaf spring 210 is formed integrally with the first housing 21, but it may also be manufactured separately from the first housing 21 and joined to the first housing 21 by, for example, welding. Similarly, the leaf springs 220, 230, and 240 may also be manufactured separately from the housing and joined to the housing.

[0108] Embodiments of the present invention have been described above. It should be noted that the above description illustrates preferred embodiments of the present invention, and the scope of the present invention is not limited thereto. In other words, the description of the configuration of the apparatus and the shape of each part is merely an example, and it is clear that various modifications and additions to these examples are possible within the scope of the present invention. [Industrial applicability]

[0109] The vibration actuator according to the present invention is useful as a vibration actuator that can apply strong vibrations over a wide range of driving frequencies, even when small in size. For example, the vibration actuator according to the present invention is suitable for installation in game controllers, game machines, vehicle seats, portable terminals (e.g., portable game terminals, portable information terminals, wearable terminals, etc.), amusement machines such as pachinko machines, and home appliances. By installing the vibration actuator according to the present invention in these devices, it is possible to provide the user with tactile feedback through vibration instead of physical switches. Furthermore, as a means of transmitting information (e.g., warnings, etc.) from the device to the user, it is also possible to provide the user with vibrations from the vibration actuator according to the present invention as tactile or tactile vibrations. [Explanation of Symbols]

[0110] 10A, 10B Vibration actuator, 20A, 20B Fixed part, 21 First housing, 22A, 22B Second housing, 23 Upper yoke, 24A, 24B Lower yoke, 25, 25a~25d Upper magnet, 26, 26a~26d Lower magnet, 30A, 30B Movable part, 31, 31a~32c Coil, 32 Plate-shaped part, 33A, 33B, 34 Weight, 40 Wiring part, 210, 220, 230, 240, 250 Leaf spring, 211 Connection part, 212, 213 Arm part, 214 Confluence / branching part, 215, 216 Support part, 260 Connecting member

Claims

1. A vibration actuator that causes a movable part housed inside a housing and elastically supported by the housing to vibrate elastically by the driving force of a drive unit, The drive unit comprises a pair of magnets fixed inside the housing so as to face each other across space, and a coil included in the movable part and arranged in the space, and generates the driving force through the interaction between the magnetic field of the magnets and the current flowing through the coil. The housing has at least one pair of first leaf springs that elastically support the movable part, The first leaf spring has a connecting portion connected to the housing, a pair of arm portions that branch symmetrically from the connecting portion and curve in a meandering shape, a merging branching portion where the pair of arm portions merge and branch off midway between the connecting portion and the ends of the pair of arm portions, and a pair of support portions arranged at the ends of the pair of arm portions to support the movable portion. Vibration actuator.

2. The housing has a first member and a second member facing each other across the space, The pair of first leaf springs are arranged on at least one of the first member and the second member. The vibration actuator according to claim 1.

3. At least one of the first member and the second member, including the pair of first leaf springs, is made of a spring material sheet. The vibration actuator according to claim 2.

4. The movable part has a pair of weights, In the aforementioned weight, both ends in the longitudinal direction are the molded surface or fracture surface. The support portion is fixed to the weight on surfaces other than the two end faces. The vibration actuator according to claim 1.

5. The movable part has a pair of weights, The pair of first leaf springs are arranged on the first member and the second member, respectively. The four pairs of support parts in the two pairs of first leaf springs are each fixed to the corresponding weight. The vibration actuator according to claim 2.

6. The movable part has a pair of weights, The first member has the pair of first leaf springs, The second member has a pair of second leaf springs having the connecting portion, the pair of arm portions, and the confluence branching portion, In each of the sets of the first leaf spring and the second leaf spring, the first leaf spring and the second leaf spring are connected, and the pair of support portions in the first leaf spring are fixed to the corresponding weights. The vibration actuator according to claim 2.

7. In place of the first leaf spring, a pair of third leaf springs are provided, having the same configuration as the first leaf spring, but with the connecting portion not connected to the housing. The movable part has a pair of weights, The second member has a pair of second leaf springs having the connecting portion, the pair of arm portions, and the confluence branching portion, In each of the sets of the third leaf spring and the second leaf spring, the third leaf spring and the second leaf spring are connected, and the pair of support portions in the third leaf spring are fixed to the corresponding weights. The vibration actuator according to claim 2.

8. A yoke is positioned inside the first member and the second member, respectively. The yoke is positioned to close the opening created by the formation of the first leaf spring. The vibration actuator according to claim 3.

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