Vibration actuator and electronic apparatus

Abstract

This vibration actuator comprises: a fixed body having a case that includes a cylindrical peripheral wall part, and a cylindrical coil disposed on one end side of the peripheral wall part inside the peripheral wall part; a movable body having a cup-shaped yoke that includes, inside the peripheral wall part, a cylindrical part disposed with a gap on an outer periphery of the coil and a closing plate part that closes the cylindrical part on the other end side of the peripheral wall part, the movable body connecting a magnet disposed with a gap inside the coil to the closing plate part inside the yoke; and a leaf spring laid on the peripheral wall part and the movable body orthogonally to the axial direction of the coil, and movably supporting the movable body in the axial direction. The movable body is provided with a weight on the outer periphery of the yoke, and a sliding part that slides on the inner peripheral surface of the peripheral wall part as the movable body moves is provided to the outer surface of the weight.

Description

Vibration actuator and electronic device

[0001] The present invention relates to a vibration actuator and an electronic device including the same.

[0002] Conventionally, a vibration actuator has been mounted as a vibration generation source in an electronic device having a vibration function. By driving the vibration actuator to transmit vibration to the user for the user to feel, the electronic device can notify an incoming call or improve the operation feeling and sense of presence. Here, the electronic device includes a portable game terminal, a controller (game pad) of a stationary game machine, a portable communication terminal such as a mobile phone or a smartphone, a portable information terminal such as a tablet PC, and a portable device of a wearable terminal that can be worn on clothes or arms.

[0003] As a vibration actuator having a miniaturizable structure to be mounted in a portable device, for example, as shown in Patent Document 1, a vibration actuator used in a pager or the like is known.

[0004] This vibration actuator supports a pair of plate-like elastic bodies at the opening edge portions of a cylindrical frame body so as to face each other. Each of the plate-like elastic bodies is disposed by fixing one end portion to a fixed body and the other end portion to a movable body. One of the pair of plate-like elastic bodies having a spiral shape has an outer peripheral portion, which is one end portion, disposed at the bottom of the frame body, and is formed such that the central portion, which is the other end portion, bulges upward from this outer peripheral portion. A yoke with a magnet attached is fixed to this central portion, and the yoke is supported within the frame body.

[0005] The yoke and the magnet together constitute a magnetic field generating body, and a coil is disposed in the magnetic field of this magnetic field generating body in a state of being attached to the other plate-like elastic body. The coil is formed into a cylindrical body using an enamel wire obtained by baking resin on the surface of a copper wire, and is a so-called air-core coil using a self-fusing wire, and the arrangement space is small. By flowing currents having different frequencies through the coil via an oscillation circuit, the pair of plate-like elastic bodies selectively resonate to generate vibration, and the yoke vibrates in the direction of the center line of the frame body within the frame body.

[0006] Japanese Patent No. 3748637

[0007] Incidentally, actuators driven by resonance, such as those described in Patent Document 1, are desired to be miniaturized and thinned as the electronic devices on which they are mounted become smaller. At this time, it is desirable that they generate strong vibrations even when miniaturized.

[0008] The objective of the present invention is to provide a vibration actuator and electronic device that can produce strong vibrations even when miniaturized.

[0009] One embodiment of the vibration actuator according to the present invention comprises: a fixed body having a case including a cylindrical peripheral wall portion and a cylindrical coil disposed at one end of the peripheral wall portion; a movable body having a cup-shaped yoke within the peripheral wall portion, including a cylindrical portion disposed with a gap around the outer circumference of the coil and a closing plate portion that closes the cylindrical portion at the other end of the peripheral wall portion, and connecting a magnet disposed with a gap inside the coil to the closing plate portion within the yoke; and a leaf spring erected on the peripheral wall portion and the movable body perpendicular to the axial direction of the coil, supporting the movable body so as to be movable in the axial direction, wherein the movable body has a weight on the outer circumference of the yoke, and the outer surface of the weight is provided with a sliding portion that slides along the inner surface of the peripheral wall portion when the movable body moves.

[0010] The electronic device of the present invention adopts a configuration that incorporates the vibration actuator with the above configuration.

[0011] According to the present invention, strong vibrations can be obtained even when the device is miniaturized.

[0012] Figure 1 is an external perspective view showing a vibration actuator according to Embodiment 1 of the present invention. Figure 2 is a longitudinal cross-sectional view taken along line A-A in Figure 1. Figure 3 is an exploded view taken from above, separating the fixed body and the movable body of the vibration actuator according to Embodiment 1 of the present invention. Figure 4 is an exploded view taken from below, separating the fixed body and the movable body of the vibration actuator according to Embodiment 1 of the present invention. Figure 5 is an upper exploded perspective view of the same vibration actuator. Figure 6 is a lower exploded perspective view of the same vibration actuator. Figures 7A and 7B show the connection state of the coils in the vibration actuator. Figure 8 is a diagram showing the magnetic circuit of the vibration actuator. Figures 9A and 9B are diagrams used to explain the operation of the vibration actuator. Figures 10A, 10B, and 10C are diagrams used to explain the eddy currents generated in the vibration actuator. Figure 11 is an exploded perspective view taken from above of a modified example of the vibration actuator according to Embodiment 1 of the present invention. Figure 12 is an exploded perspective view taken from below of a modified example of the vibration actuator according to Embodiment 1 of the present invention. Figure 13 is a longitudinal cross-section of the vibration actuator according to Embodiment 2 of the present invention. Figure 14 is an exploded view from above showing the fixed body and movable body separated in a vibration actuator according to Embodiment 2 of the present invention. Figure 15 is an exploded view from below showing the fixed body and movable body separated in a vibration actuator according to Embodiment 2 of the present invention. Figure 16 is an exploded upper perspective view of the vibration actuator according to Embodiment 2 of the present invention. Figure 17 is an exploded lower perspective view of the vibration actuator according to Embodiment 2 of the present invention. Figure 18 is a diagram showing an example of an electronic device on which the vibration actuator is mounted. Figure 19 is a diagram showing an example of an electronic device on which the vibration actuator is mounted.

[0013] Embodiments of the present invention will be described in detail below with reference to the drawings. Common components in each drawing are denoted by the same reference numerals, and their descriptions will be omitted as appropriate.

[0014] (Embodiment 1) In the following description, "upper" and "lower" in terms such as "upper side" and "lower side" are added for convenience to make it easier to understand the configuration and behavior of the vibration actuator 1 according to this embodiment. When the vibration actuator 1 is mounted on electronic equipment (see Figures 18 and 19), the "upper" and "lower" described herein may be reversed, left and right, or diagonal. Incidentally, in this embodiment, the vertical direction is the vibration direction of the movable body in the vibration actuator, "upper direction" is one direction of vibration, and "downper direction" is the other direction of vibration. That is, the vibration actuator is a linear actuator that vibrates the movable body linearly in the vertical direction.

[0015] Furthermore, in the following explanation, unless otherwise specified, "radial direction" refers to the direction extending radially or centrifugally around the central axis that extends vertically in a vibration actuator. Also, "outside" and "inside" in terms such as "outside" and "inside" refer to the outward and inward directions in the radial direction around the central axis. Furthermore, unless otherwise specified, "circumferential direction" refers to the direction extending around the central axis.

[0016] Furthermore, it goes without saying that the expressions used to describe shapes in the following description are for convenience in providing a simplified general overview, and do not necessarily correspond to geometrically precise definitions of shapes. The shapes of the entire apparatus or its components described herein are examples only, and the present invention is not limited to the shapes exemplified in this embodiment.

[0017] Figure 1 is an external perspective view showing a vibration actuator according to Embodiment 1 of the present invention, and Figure 2 is a longitudinal cross-sectional view taken along line A-A in Figure 1. Figure 3 is an exploded view from above showing the fixed body and movable body separated in the vibration actuator according to Embodiment 1 of the present invention, and Figure 4 is an exploded view from below showing the fixed body and movable body separated in the vibration actuator according to Embodiment 1 of the present invention.

[0018] The vibration actuator 1 according to this embodiment houses a movable body 5 via an elastic support portion 7 within a fixed body 3 that constitutes a hollow case, so that the movable body 5 can vibrate in the axial direction (vertical direction) of the case. The vibration actuator 1, for example, houses a movable body 5 that is connected at the top to the central inner circumference of the elastic support portion 7 inside a fixed body 3 with a bottomed cylindrical shape. The outer circumference of the elastic support portion 7 is fixed between the fixed body 3 and the lid portion 4, and the movable body 5 is housed in a suspended state within the case. The vibration actuator 1 vibrates the movable body 5 in the axial direction within the case through the cooperation of the coil 34 of the fixed body 3 and the magnet 51 of the movable body 5. The vibration actuator 1 itself functions as a small, high-power vibrating device due to the vibration of the movable body 5.

[0019] The vibration actuator 1 is implemented as a vibration source in electronic devices such as portable game terminals (for example, the game controller GC shown in Figure 18) to realize the vibration function of the electronic device. This electronic device also includes portable devices such as smartphones (for example, the mobile terminal M shown in Figure 19). The vibration actuator 1 is implemented in portable game terminals or other portable devices, and when driven, it vibrates to notify the user of incoming calls or to provide a sense of operation and realism.

[0020] Furthermore, the vibration actuator 1 may be mounted on a wearable device such as a wearable activity tracker or a pen-type input device such as a stylus.

[0021] Figure 5 is an exploded upper perspective view of the vibration actuator, and Figure 6 is an exploded lower perspective view of the vibration actuator. Figures 7A and 7B show the coil connection state in the vibration actuator.

[0022] <Stabilizer 3> The stabilizer (stator section) 3 has a cylindrical case body 32, a coil 34, a bottom surface 33, a coil holder 36, and a base plate section 37.

[0023] The case body 32 is cylindrical and houses the movable body 5 movably inside. The inner circumferential surface 32a is preferably smooth, allowing the vibrating movable body 5 to slide on it.

[0024] The case body 32 has a lid portion 4 fixed to one open end (upper opening edge) via an elastic support portion 7, and a bottom portion 33 fixed to the other open end (lower opening edge).

[0025] The case body 32 is made of a metal such as SUS, similar to the top surface 44 and bottom surface 33, and is formed by processing sheet metal, ensuring a highly accurate inner circumferential surface 32a.

[0026] The coil 34 is arranged around the outer circumference of the magnet 51, surrounding the magnet 51. Preferably, the coil 34 is cylindrical in shape and arranged to have the same axis as the magnet 51, case, etc.

[0027] When energized, the coil 34 works in cooperation with the magnet 51 to drive the movable body 5 in the axial direction using a VCM structure. The space utilization can be increased by setting the dimensions of the coil 34.

[0028] The bottom portion 33 supports the coil 34 in a positioned and arranged state within the case via the coil holder 36 on the front side (inside the case), and holds the substrate portion 37 on the back side.

[0029] The bottom portion 33 is fixed so as to close the lower end opening of the cylindrical case body 32. The bottom portion 33 is plate-shaped and has an opening 332 in the center. The holder body (cylindrical body portion) 362 of the coil holder 36 is positioned in the opening 332 so as to protrude into the case, and the flange portion 364 engages with and fixes it on the back surface (outside the case, one end surface) of the bottom portion 33. The bottom portion 33 supports the coil holder 36 so that the holder body (cylindrical body portion) 362 is on the same axis.

[0030] The bottom surface 33 restricts the direction of movement of the movable body 5, which moves inside the case, by contacting it, and functions as a hard stop when it moves beyond a predetermined range. The bottom surface 33 is formed by processing sheet metal such as stainless steel, ensuring surface accuracy. Furthermore, since the bottom surface 33 is formed by using sheet metal as is to ensure surface accuracy, it is possible to reduce costs and make the device thinner.

[0031] Furthermore, the bottom portion 33 has a notch (communication portion) 334 that is continuous with the opening 332. The notch (communication portion) 334 releases air that moves with the movement of the movable body 5 to the outside. Also, through the notch (communication portion) 334, the coil wire 342, which is the terminal of the coil 34 inside the case, is led out to the outside of the case (the back side of the bottom portion 33) and connected to the pad 374 of the circuit of the substrate portion 37 which is located on the back side of the bottom portion 33 (outside the case, one end face).

[0032] The coil wire 342 consists of one wire from the inner circumference of the coil 34 and one wire from the outer circumference. The coil wire 342 from the inner circumference is suitably led out from the lower surface of the coil 34 to the outside via the notch 334 and the notch 366 of the flange portion 364 of the coil holder 36.

[0033] The coil holder 36 holds the coil 34 on the bottom side inside the case, radially outward from the magnet 51, and at a predetermined distance from the magnet 51. The coil holder 36 has a cylindrical holder body 362 that holds the coil 34 arranged on the outer circumference, and a flange portion 364 that protrudes outward from the base end of the cylindrical holder body 362.

[0034] The coil holder 36 reinforces the coil 34 via the outer circumferential surface of the holder body 362, protecting it from collision with the magnet 51.

[0035] The coil holder 36 is fixed by inserting the holder body 362 into the opening 332 of the bottom portion 33 from the back side of the bottom portion 33 and hooking the flange portion 364 onto the opening edge on the back side of the bottom portion 33. As a result, the holder body 362 is positioned within the case in such a way that it protrudes inward from the center of the bottom portion 33 of the case, and is on the same axis as the axis of the case and the axis of the movable body 5.

[0036] In the holder body 362, the coil 34 is fitted onto a portion that protrudes from the surface side of the bottom portion 33. For example, the coil 34 is positioned on the bottom portion 33.

[0037] Furthermore, a notch 366 is formed in part of the flange portion 364 and is arranged continuously with the notch 334 of the bottom portion 33, facilitating the routing of the coil wire 342 of the coil 34 to the outside, as described above. That is, as shown in Figures 7A and 7B, a gap is formed between the lower surface of the coil 34 and the flange portion 364 via the notch 334 of the bottom portion 33.

[0038] Through this gap, the coil wire 342 is led out from the inner lower surface of the coil 34 to the outside, as shown in portion X1 of Figure 7B. The coil wire 342 led out to the outside is suitably connected to the substrate portion 37 which is located on the outer surface of the bottom portion 33.

[0039] Since the coil wires 342 are placed in the gaps between the coil 34, they are not stacked on the bottom surface 33 in the axial direction of the coil 34, that is, in the height direction, making it possible to make the device thinner.

[0040] Furthermore, the coil holder 36 is made of a conductive material and has the function of generating eddy currents when the movable body 5 moves, thereby suppressing vibration of the movable body 5. The coil holder 36 is formed using a highly conductive material such as copper, aluminum, or an alloy thereof.

[0041] The coil holder 36 (particularly the cylindrical holder body 362) generates eddy currents when the movable body 5 moves due to resonant drive, thereby suppressing the acceleration that increases due to resonance. The coil holder 36 is fixed by inserting the holder body 362 into the opening 332 and fitting it into the bottom surface 33, so it can be precisely positioned and mounted coaxially with respect to the bottom surface 33. Since the coil holder 36 is made of a conductive material, even when the coil 34 generates heat due to current flow, the heat can be suitably dissipated to the outside through the coil holder 36.

[0042] The substrate portion 37 is connected to the coil and has a circuit for supplying current to the coil 34 from the outside. The substrate portion 37 is formed in an annular plate shape, and is configured by providing a reinforcing layer 372 made of sheet metal or the like on the substrate main body 371 so as to cover the circuit. The coil wire 342 of the coil 34 is connected to the exposed pad 374. A lead wire 38 is connected to the exposed pad 376, and connects the substrate portion 37 and an external power supply unit. The reinforcing layer 372 ensures surface accuracy, and cost reduction and thinning are achieved. The substrate portion 37 is attached here so as to surround the opening 332 on the back surface of the bottom portion 33, and is attached entirely here. Thus, since the substrate portion 37 is attached to the back surface of the bottom portion 33, it is not disposed inside the case (on the surface side of the bottom portion 33), so that a movable region of the movable body 5 inside the case can be secured.

[0043] <Movable body 5> The movable body 5 has a magnet 51 disposed inside the coil 34, and is housed slidably in the axial direction inside the case main body 32 of the fixed body 3 in a state of being suspended via the elastic support portion 7.

[0044] The movable body 5 has an annular sliding portion 60 having a weight portion 50, an outer yoke 53, an inner yoke 54, and a sliding protrusion 62 in addition to the magnet 51, and is supported in a state of being suspended by the elastic support portion 7.

[0045] The magnet 51 is a solid plate magnetized in the vibration direction, and is formed in a disk shape (including a plate shape). The magnet 51 constitutes a magnetic circuit that drives the movable body 5 together with the outer yoke 53, the inner yoke 54, the coil 34, and the holder main body 362. The magnet 51 is disposed so as to be spaced apart inside the coil 34 in the radial direction with respect to the coil 34 held by the coil holder 36. Here, the "radial direction" is also a direction orthogonal to the axial direction (vibration direction) of the coil 34.

[0046] The magnet 51 is connected to the inner surface of the central portion of the top surface portion (closing plate portion) 532 of the outer yoke 53 at the upper surface 51a. The magnet 51 is disposed so as to face the inner peripheral surface of the holder main body 362 of the coil holder 36 on the inner side in the radial direction.

[0047] In the magnet 51, for example, it is magnetized in the axial direction (vibration direction), and the upper and lower surfaces 51a and 51b that are spaced apart in the axial direction have different polarities respectively.

[0048] Since the magnet 51 is a solid cylindrical shape, it can be manufactured at a lower cost compared to a magnet with processed concave portions or the like. The magnet 51 is, for example, a neodymium sintered magnet, and by increasing the weight of the movable part, higher output by magnetic drive is achieved. Also, the magnet 51 functions as a weight of the movable body 5. The resonance frequency can be adjusted by the plate thickness of the magnet 51 and the spring length of the elastic support portion 7.

[0049] The outer yoke 53 is made of a magnetic material, houses the magnet 51, and together with the magnet 51 and the inner yoke 54, constitutes a magnetic path. The outer yoke 53 constitutes a magnetic circuit together with the coil 34, the coil holder 36, the magnet 51, and the inner yoke 54.

[0050] The outer yoke 53 is, for example, composed of an iron-based soft magnetic material and can be formed into an arbitrary shape by a sintered material. The outer yoke 53 can ensure a degree of freedom in shape. The outer yoke 53 can also function as a weight in the movable body 5 to amplify vibration.

[0051] Specifically, the outer yoke 53 is a cup-shaped, that is, a covered cylindrical magnetic body, and is connected to the magnet 51 to constitute the magnetic circuit of the vibration actuator 1. The outer yoke 53 has a top surface portion 532 connected at the upper surface 51a of the magnet 51 and a yoke cylindrical portion 534 vertically provided at the outer peripheral edge of the top surface portion 532.

[0052] The outer yoke 53 houses the magnet 51 with the axis of the magnet 51 positioned at the center of the top surface portion 532 so as to be coaxial with the center of the movable body 5.

[0053] The top surface portion 532 is disc-shaped and concentrates the magnetic flux from the upper surface 51a of the magnet 51. It is thicker than the yoke cylindrical portion 534. A recess 536 is formed in the center of the upper surface of the top surface portion 532, and the thickness of this portion, i.e., the portion where the magnetic flux is concentrated, is thin. As a result, the magnetic flux flowing through the yoke cylindrical portion 534, the top surface portion 532, and the magnet 51 flows efficiently from the top surface portion 532 to the yoke cylindrical portion 534, or from the yoke cylindrical portion 534 to the top surface portion 532.

[0054] The yoke-shaped cylindrical portion 534 is positioned spaced apart from the outer circumference of the magnet 51 and surrounds the magnet 51.

[0055] Between the yoke cylindrical portion 534 and the magnet 51, the holder body 362 of the coil holder 36 and the coil 34 are arranged to be movable in the vertical direction. The yoke cylindrical portion 534 is positioned to face the upper part of the coil 34 circumferentially outward.

[0056] The lower end of the yoke cylindrical portion 534 is positioned to protrude below the lower surface 51b of the magnet 51, and is at the same height level as the vertical center of the inner yoke 54.

[0057] The outer yoke 53 is joined to the tip weight portion 57, which is the upper part of the weight portion 50, by fitting the projection 574 into the recess 536, thereby axially extending the yoke.

[0058] The inner yoke 54 is a plate-shaped magnetic material, has the same outer diameter as the magnet 51, and is joined to the lower surface 51b of the magnet 51. The inner yoke 54 also functions as a weight.

[0059] The weight portion 50 increases the weight of the movable body 5, which has a magnet 51, thereby increasing the amount of vibration. The weight portion 50 is fixed in alignment with the elastic support portion 7, which amplifies the vibration. An annular sliding portion 60 is fitted onto the outer circumference (outer surface) of the weight portion.

[0060] The weight portion 50 connects the magnetic circuit portion on the movable body side, such as the magnet 51, to the elastic support portion 7.

[0061] If the weight portion 50 is made of a high-density material such as tungsten, the weight of the movable body can be increased, thereby improving the amount of vibration.

[0062] The weight portion 50 is provided to cover the outer surface of the outer yoke 53, excluding the opening. The weight portion 50 has a cylindrical main weight portion 55 fixed to the outer circumference of the yoke cylindrical portion 534 of the outer yoke 53, and a tip weight portion 57 fixed to the upper surface of the main weight portion 55 and the top surface portion 532 of the outer yoke 53.

[0063] The main body weight portion 55 is constructed by combining annular weight portions 55a and 55b. The annular weight portions 55a and 55b are formed in the same shape, and a notch 552 extends in the circumferential direction from the outer circumference of each annular weight portion 55a and 55b.

[0064] The main body weight portion 55 is formed by placing the annular sliding portion 60 in a recess formed by joining the annular weight portions 55a and 55b together, and fixing them so as to sandwich the annular sliding portion 60 between them in the axial direction.

[0065] The annular weight portions 55a and 55b sandwich and fix the annular sliding portion 60, so that the annular sliding portion 60 is sandwiched between the main weight portion 55 in the direction of vibration. As a result, even when the movable body 5 moves in the direction of vibration and the sliding projection 62 slides on the inner circumferential surface 32a, the annular sliding portion 60 having the sliding projection 62 does not come off, and the movable body 5 moves suitably in the direction of vibration.

[0066] The annular sliding portion 60 is an annular body that constitutes a part of the outer circumferential surface of the movable body 5, and has a plurality of sliding projections 62 that protrude radially outward from the outer circumferential surface of the movable body 5. The annular sliding portion 60 is arranged on the movable body 5 such that the sliding projections 62 are positioned at predetermined intervals on the outer circumferential surface of the movable body 5.

[0067] The sliding projection 62 is preferably made of a material with high sliding properties, and is composed of a material with a low coefficient of friction, such as a resin such as POM (polyacetal polyoxymethylene) resin. The sliding projection 62 is formed of a resin such as POM resin as part of the annular sliding portion 60 and is provided so as to be located on the outer circumference of the movable body 5.

[0068] The sliding projection 62 slides along the inner circumferential surface 32a of the case body 32, suppressing radial vibration of the movable body 5. In addition, since the sliding projection 62 contacts the inner circumferential surface 32a (for example, point contact or line contact), the loss of driving force due to sliding is reduced.

[0069] The sliding projection 62 is integrally provided with the annular sliding portion 60, which is separate from the weight portion 50, and is formed from a highly sliding component such as POM resin, similar to the annular sliding portion, so that sliding loss and sliding noise can be suppressed more effectively.

[0070] The tip weight portion 57 here comprises a tip weight portion body 572 formed in a trapezoidal cross-section, a spring joint portion 576 provided on the upper part of the tip weight portion body 572, and a projection portion 574 protruding from the center of the lower surface of the tip weight portion body 572.

[0071] The inclined portions on both sides of the tip weight body 572 (both sides of the upper part of the movable body 5) are configured so as not to interfere with the elastic support portion 7, which deforms when the movable body 5 moves.

[0072] The spring joint portion 576 fits into the connection hole 72a of the inner circumference portion 72 of the elastic support portion 7, and the inner circumference portion of the elastic support portion 7 fits onto the stepped portion 578.

[0073] The projection 574 fits into the recess 536 of the outer yoke 53, and the tip weight 57 is fixed in close contact with the upper surfaces of the outer yoke 53 and the main body weight 55, respectively.

[0074] <Elastic support part 7> The elastic support part 7 elastically supports the movable body 5 within the case so that it can reciprocate and slide in the direction of vibration. The elastic support part 7 is, for example, a leaf spring formed in the shape of a disc.

[0075] The elastic support section 7 allows for adjustment of the displacement and resonant frequency of the movable body 5 by adjusting the plate thickness and spring length.

[0076] The elastic support portion 7 mainly consists of an inner circumference portion 72 fixed to the tip weight portion 57 of the movable body 5 inside the case body 32, an outer circumference portion 76 fixed to one of the opening edges of the case body 32, and a deformable arm 74 that connects the inner circumference portion 72 and the outer circumference portion 76 and undergoes elastic deformation. The elastic support portion 7 is installed on both the movable body 5 and the opening edge of the fixed body 3 so as to intersect with the direction of vibration.

[0077] The deformable arm 74 is arranged in a spiral shape connecting the inner circumference 72 and the outer circumference 76, and the deformation of the deformable arm 74 causes the inner circumference 72 and the outer circumference 76 to be displaced relative to each other in the axial direction.

[0078] The inner circumference 72 has a connection hole 72a located in the center of the elastic support portion 7. The spring joint portion 576 of the tip weight portion 57 of the movable body 5 is fitted into and connected to this connection hole 72a. On the other hand, the outer circumference 76 is sandwiched between the case body 32 and the lid peripheral wall portion 42 of the fixed body with adhesive or the like.

[0079] The leaf spring serving as the elastic support portion 7 can be made from any material that is elastically deformable, and may be formed by sheet metal processing using stainless steel plate, phosphor bronze, etc. The elastic support portion 7 may also be made of resin, as long as it supports the movable body 5 in a vibratory manner. Furthermore, since the elastic support portion 7 is flat, it is possible to improve positional accuracy, i.e., processing accuracy, compared to a conical spring.

[0080] <Lid 4> The lid 4 has a lid peripheral wall portion 42 and a top surface portion 44, is formed in a covered cylindrical shape, and closes the upper part of the fixing body 3. The lid 4 may also be part of the fixing body.

[0081] The lid periphery wall portion 42, together with the case body 32, fixes the elastic support portion 7. The lid periphery wall portion 42 is formed in a cylindrical shape, for example, a cylindrical shape. By changing the height of the lid periphery wall portion 42, the displacement height of the movable body 5 can be set.

[0082] The top surface portion 44 is fixed so as to close one (upper) opening of the lid peripheral wall portion 42. An air vent hole (communication portion) 442 is formed in the top surface portion 44. The top surface portion 44 is disc-shaped, and the notches provided on the outer circumference function as the air vent hole (communication portion) 442. The air vent hole (communication portion) 442 releases air when the movable body 5 moves. This prevents a decrease in vibration amount due to the air inside.

[0083] Furthermore, the top surface portion 44 functions as a hard stop in the direction of withdrawal when the movable body 5 moves, and also suppresses the intrusion of foreign matter into the interior.

[0084] <Operation of the Vibration Actuator> Figure 8 shows the magnetic circuit of the vibration actuator. Figures 9A and 9B are diagrams used to explain the operation of the vibration actuator.

[0085] As shown in Figure 8, when the vibration actuator 1 is not driven, the magnetic flux flows from the magnet 51 to the inner yoke 54, through the coil 34, through the yoke cylindrical portion 534 of the outer yoke 53, through the top surface portion 532, and back to the magnet 51.

[0086] As shown in Figure 9A, when current is passed through the coil 34, the interaction between the magnetic field of the magnet 51 and the current flowing through the coil 34 generates a downward Lorentz force in the coil 34 according to Fleming's left-hand rule. The downward Lorentz force is perpendicular to the direction of the magnetic field and the direction of the current flowing through the coil 34. Since the coil 34 is part of the stationary body 3, according to the law of action and reaction, a force opposite to this Lorentz force is generated in the movable body 5 having the magnet 51 as a thrust in the F direction. As a result, the movable body 5 having the magnet 51 moves in the F direction, towards the lid 4.

[0087] Furthermore, when the current flow direction of coil 34 is reversed and current flows to coil 34, a Lorentz force in the opposite direction (upward) is generated, as shown in Figure 9B. Due to the generation of this upward Lorentz force, according to the law of action and reaction, a force opposite to this Lorentz force in the F direction is generated as a thrust (thrust in the -F direction) on the movable body 5, and the movable body 5 moves in the -F direction, that is, towards the bottom surface 33 of the fixed body 3. In the vibration actuator 1, when it is not driven (non-vibrating) and no current is flowing, the movable body 5 is positioned in the initial position shown in Figure 8 due to the biasing force of the elastic support part 7.

[0088] In the vibration actuator 1, the movable body 5 generates vibrations while sliding within the case body 32, which allows for a reduced clearance between the movable body 5 and the fixed body 3. This enables more effective use of the space that would otherwise be used to increase the weight of the movable body 5, thus allowing for miniaturization. Furthermore, the impact resistance of the movable body 5 can be ensured.

[0089] In the vibration actuator 1, the movable body 5 is displaced and vibration is generated by changing the magnitude and / or direction of the current. In this embodiment, the vibration actuator 1 has a function to suppress the resonance peak by generating eddy currents when the movable body 5 moves.

[0090] Figures 10A, 10B, and 10C are diagrams illustrating the eddy currents generated by the vibration actuator. Figure 10A is a partial cross-sectional view showing the movement of the movable body 5. Figure 10B is a partial cross-sectional view showing the state of the holder body 362 of the coil holder 36 during the movement shown in Figure 10A. Figure 10C shows the frequency characteristics of the vibration amount of the vibration actuator in this embodiment using a copper coil holder that generates eddy currents, and the frequency characteristics of the vibration amount of the vibration actuator using a resin coil holder that does not generate eddy currents.

[0091] In the vibration actuator 1, as shown in Figure 10A, the movable body 5 moves (for example, upward) through the cooperation of the energized coil and the magnet 51. As the moving movable body 5 moves while a magnetic field is formed (a state in which a flow of magnetic flux is generated), the holder body 362, which is a conductive member, is positioned within that magnetic field (magnetic path, magnetic circuit). In the holder body 362, which is a conductive member, the magnetic flux passing through it changes, generating eddy currents as shown in Figure 10B, and an induced current flows in the direction that opposes the change in magnetic flux, that is, the movement of the movable body 5. As a result, the eddy currents increase in proportion to the magnitude of the change in magnetic flux, and vibration damping can be achieved.

[0092] As shown in Figure 10C, in the vibration actuator 1 of this embodiment, the vibration amount [Gpp] when using a copper coil holder and when the coil holder is changed to a resin coil holder is such that eddy current attenuation occurs in the configuration using copper, and the resonance peak is suppressed. As a result, according to this embodiment, acceleration during resonant driving can be suppressed, and a strong vibration output can be suitably realized over a wide frequency range.

[0093] <Modified Examples> Figure 11 is an exploded perspective view from above of a modified example of the vibration actuator according to Embodiment 1 of the present invention, and Figure 12 is an exploded perspective view from below of a modified example of the vibration actuator according to Embodiment 1 of the present invention.

[0094] In the vibration actuator 1 shown in Figures 1 to 7, the case body 32 and the bottom portion 33 are separate components. However, as shown in Figures 11 and 12, the case body 32 and the bottom portion 33 may be integrated into a single case body 32A. The vibration actuator 1A having a case body 32A differs from the vibration actuator 1 in that the case body 32A has the functions of both the case body 32 and the bottom portion 33. Other configurations are the same, so a detailed explanation is omitted.

[0095] In the vibration actuator 1A shown in Figure 11, the holder body 362 of the coil holder 36 is inserted into the bottom surface 33 of the case body 32A and fixed with the flange portion 364, causing the holder body 362 to protrude into the case body 32A. Also, similar to the vibration actuator 1, the coil 34 is arranged on the outer surface of the holder body 362, and the movable body 5 is held within the case body 32A so as to be movable in the axial direction via the elastic support portion 7. The magnet 51 of the movable body 5 is arranged inside the holder body 362. The yoke cylindrical portion 534 of the outer yoke 53 is arranged radially outside the coil 34.

[0096] As a result, the number of parts is reduced compared to the vibration actuator 1, making manufacturing easier, and the case body 32A can be constructed as a bottomed cylindrical shape to improve strength.

[0097] (Embodiment 2) Figure 13 is a longitudinal cross-section of the vibration actuator according to Embodiment 2 of the present invention, and Figure 14 is an exploded view from above showing the fixed body and movable body separated in the vibration actuator according to Embodiment 2 of the present invention. Figure 15 is an exploded view from below showing the fixed body and movable body separated in the vibration actuator according to Embodiment 2 of the present invention, and Figure 16 is an upper exploded perspective view of the vibration actuator according to Embodiment 2 of the present invention. Figure 17 is a lower exploded perspective view of the vibration actuator according to Embodiment 2 of the present invention.

[0098] Note that the vibration actuator 1B shown in Figures 13 to 17 has the same basic configuration as the vibration actuator 1 corresponding to Embodiment 1 shown in Figure 1, and the same reference numerals are used for the same components, and their descriptions are omitted.

[0099] The vibration actuator 1A shown in Figures 13 to 17 differs from the vibration actuator 1 only in the configuration of the movable body 5B; all other configurations are the same.

[0100] The vibration actuator 1B according to this embodiment houses a movable body 5B via an elastic support portion 7 within a fixed body 3 that constitutes a hollow case, so that the vibration direction is in the axial direction (up and down direction) of the case.

[0101] The fixed body (stator section) 3 has a cylindrical case body 32, a coil 34, a bottom section 33, a coil holder 36, and a base section 37. The movable body 5B has a magnet 51, a weight section 50B, an outer yoke 53, an inner yoke 54, and an annular sliding section 60B with a sliding projection 62, and is supported while suspended from the elastic support section 7.

[0102] The weight portion 50B has a similar function to the weight portion 50 of the vibration actuator 1, but differs in that the weight portion 50B is divided into two parts. The weight portion 50B has a cylindrical main weight portion 56 fixed to the outer circumference of the yoke cylindrical portion 534 of the outer yoke 53, and a tip weight portion 57 fixed to the upper surface of the main weight portion 55 and the top surface portion 532 of the outer yoke 53.

[0103] The main weight portion 56 is cylindrical and has a large-diameter cylindrical portion 562 at the top and a small-diameter cylindrical portion 564 at the bottom that is cut out in the circumferential direction. A step is formed between the large-diameter cylindrical portion 562 and the small-diameter cylindrical portion 564, and an annular sliding portion 60B that engages with the step is arranged on the outer circumference of the small-diameter cylindrical portion 564. Both the large-diameter cylindrical portion 562 and the small-diameter cylindrical portion 564 of the main weight portion 56 are fixed to the outer surface of the outer yoke 53 via adhesive or the like on their inner circumferential surfaces.

[0104] The annular sliding portion 60B is an annular body that forms part of the outer circumferential surface of the movable body 5 and is fitted onto and fixed to the small diameter cylindrical portion 564. The annular sliding portion 60B has a plurality of sliding projections 62B on its outer circumferential surface. The annular sliding portion 60 is arranged on the movable body 5B such that the sliding projections 62B are positioned at predetermined intervals on the outer circumferential surface of the movable body 5B. The sliding projections 62B have a linear tip that is long in the axial direction, and this tip slides against the inner circumferential surface 32a of the case body 32.

[0105] The sliding projection 62B is preferably made of a material with high sliding properties, and is composed of a material with a low coefficient of friction, such as a resin such as POM (polyacetal polyoxymethylene) resin. The sliding projection 62B is formed of a resin such as POM resin as part of the annular sliding portion 60 and is provided to be located on the outer circumference of the movable body 5.

[0106] Since the sliding projection 62 slides in line contact with the inner circumferential surface 32a of the case body 32, radial vibration of the movable body 5 is suppressed. In addition, axial sliding can be performed efficiently, reducing the loss of driving force due to sliding.

[0107] The tip weight portion 57 is fitted into the connection hole 72a of the inner circumference portion 72 of the elastic support portion 7 via the upper spring joint portion 576, and has the same effect as that of the vibration actuator 1. In addition, the lower projection portion 574 of the tip weight portion 57 is fitted into the recess portion 536 of the outer yoke 53, and the tip weight portion 57 is fixed in close contact with the upper surfaces of the outer yoke 53 and the main weight portion 56, respectively.

[0108] Furthermore, the weight portion 50B can reduce the number of parts compared to the weight portion 50 of the vibration actuator 1 shown in Figure 1.

[0109] (Electronic Devices) Figures 18 and 19 show examples of electronic devices on which the vibration actuator is implemented. Figure 18 shows an example in which the vibration actuator 1 is implemented in a game controller GC, and Figure 19 shows an example in which the vibration actuator 1 is implemented in a mobile terminal M.

[0110] The Game Controller GC is connected to the game console, for example, via wireless communication, and is used by the user by gripping or holding it. In Figure 19, the Game Controller GC has a rectangular plate shape, and the user operates it by grasping both sides of the Game Controller GC with both hands.

[0111] The Game Controller GC notifies the user of commands from the game console via vibration. Although not shown in the diagram, the Game Controller GC also includes functions other than command notification, such as an input control unit for the game console.

[0112] Mobile device M is, for example, a mobile communication device such as a cell phone or a smartphone. Mobile device M notifies the user of incoming calls from external communication devices through vibration, and also enables various functions of mobile device M (for example, functions that provide a sense of operation and realism).

[0113] As shown in Figures 19 and 20, the game controller GC and the mobile terminal M each have a communication unit 201, a processing unit 202, a drive control unit 203, and vibration actuators 204, 205, and 206, which are vibration actuators 1 acting as drive units. In the game controller GC, multiple vibration actuators 204 and 205 are implemented.

[0114] In the game controller GC and the mobile terminal M, it is preferable that the vibration actuators 204 to 206 are mounted such that, for example, the main surface of the terminal and the surface perpendicular to the vibration direction of the vibration actuators 204 to 206, in this case the bottom surface of the bottom portion 114, are parallel.

[0115] The main surface of the terminal is the surface that contacts the user's body surface, and in this embodiment, it refers to the vibration transmission surface that contacts the user's body surface and transmits vibrations. The main surface of the terminal and the bottom surface of the bottom 114 of the vibration actuators 204, 205, and 206 may be arranged to be perpendicular to each other.

[0116] Specifically, in the Game Controller GC, vibration actuators 204 and 205 are mounted so that the vibration direction is perpendicular to the surface that the user's fingertips, fingertips, and hand make contact with, or the surface on which the control unit is located. In the case of the mobile terminal M, vibration actuator 206 is mounted so that the vibration direction is perpendicular to the display screen (touch panel surface). As a result, vibrations perpendicular to the main surface of the Game Controller GC and the mobile terminal M are transmitted to the user.

[0117] The communication unit 201 is connected to an external communication device via wireless communication and receives signals from the communication device, outputting them to the processing unit 202. In the case of the Game Controller GC, the external communication device is the game console itself, which acts as an information communication terminal, and communication is performed according to a short-range wireless communication standard such as Bluetooth®. In the case of the mobile terminal M, the external communication device is, for example, a base station, and communication is performed according to a mobile communication standard.

[0118] The processing unit 202 converts the input signal into a drive signal for driving the vibration actuators 204, 205, and 206 using a conversion circuit unit (not shown) and outputs it to the drive control unit 203. In the mobile terminal M, the processing unit 202 generates the drive signal based on signals input from the communication unit 201 as well as signals input from various functional units (not shown, for example, operation units such as a touch panel).

[0119] The drive control unit 203 is connected to the vibration actuators 204, 205, and 206, and has circuits implemented to drive the vibration actuators 204, 205, and 206. The drive control unit 203 supplies drive signals to the vibration actuators 204, 205, and 206.

[0120] The vibration actuators 204, 205, and 206 are driven according to the drive signals from the drive control unit 203. Specifically, in the vibration actuators 204, 205, and 206, the movable body 5 vibrates in a direction perpendicular to the main surface of the game controller GC and the mobile terminal M.

[0121] Since vibrations perpendicular to the body surface are transmitted to the user's body surface when they come into contact with the game controller GC or mobile device M, sufficient tactile vibrations can be provided to the user. With the game controller GC, tactile vibrations can be provided to the user by one or both of the vibration actuators 204 and 205, and highly expressive vibrations can be provided, such as selectively applying vibrations of varying strengths.

[0122] All disclosures in the specification, drawings, and abstract contained in the Japanese application No. 2024-230465, filed on December 26, 2024, are incorporated herein by reference.

[0123] 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.

[0124] The vibration actuator according to the present invention has the effect of being able to produce strong vibrations even when miniaturized, and is useful for use in electronic devices such as stylus pens, wearable devices, and game controllers.

[0125] 1, 1A, 1B, 204, 205, 206 Vibration actuator, 3 Fixed body, 4 Cover, 5, 5B Movable body, 7 Elastic support part (leaf spring), 32, 32A Case body, 32a Inner surface, 33 Bottom surface, 34 Coil, 36 Coil holder, 37 Base plate, 38 Lead wire, 42 Cover peripheral wall, 44 Top surface, 50, 50B Weight part, 51 Magnet, 51a Top surface, 51b Bottom surface, 53 Outer yoke, 54 Inner yoke, 55, 56 Main body weight part, 55a, 55b Annular weight part (weight), 57 Tip weight part, 60, 60B Annular sliding part (sliding part), 62, 62B Sliding projection part (sliding part), 72, 802 Inner circumference, 72a, 802a Connection holes, 74 Deformable arm, 76 Outer circumference, 114 Bottom, 201 Communication section, 202 Processing section, 203 Drive control section, 332 Opening, 334 Notch, 342 Coil wire, 362 Holder body (cylindrical body section), 364 Flange section, 366, 552 Notch, 371 Substrate body, 372 Reinforcement layer, 374, 376 Pad, 442 Air vent hole (communication section), 532 Top surface (closing plate section), 534 Yoke cylindrical section, 536 Recessed section, 562 Large diameter cylindrical section, 564 Small diameter cylindrical section, 572 Tip weight section body, 574 Projection, 576 Spring joint section, 578 Stepped section

Claims

1. A vibration actuator comprising: a fixed body having a case including a cylindrical peripheral wall portion and a cylindrical coil disposed at one end of the peripheral wall portion; a movable body having a cup-shaped yoke within the peripheral wall portion, including a cylindrical portion disposed with a gap around the outer circumference of the coil and a closing plate portion that closes the cylindrical portion at the other end of the peripheral wall portion, and a magnet disposed with a gap inside the coil connected to the closing plate portion within the yoke; and a leaf spring erected on the peripheral wall portion and the movable body perpendicular to the axial direction of the coil, supporting the movable body so as to be movable in the axial direction, wherein the movable body has a weight on the outer circumference of the yoke, and the outer surface of the weight is provided with a sliding portion that slides along the inner surface of the peripheral wall portion when the movable body moves.

2. The vibration actuator according to claim 1, wherein the weight is made of tungsten and its alloys.

3. The vibration actuator according to claim 1, wherein the sliding part is separate from the weight.

4. The vibration actuator according to claim 1, wherein the sliding portion is fitted onto the weight and protrudes from the outer circumferential surface of the weight.

5. The vibration actuator according to claim 4, wherein the sliding portion is sandwiched in the axial direction by the divided weight.

6. The vibration actuator according to claim 1, wherein the sliding portion comprises a plurality of sliding protrusions that project radially outward from the outer circumferential surface of the weight, and each of these protrusions slides linearly along the axial direction on the inner circumferential surface.

7. The vibration actuator according to claim 1, wherein the sliding part is made of polyacetal resin.

8. The vibration actuator according to claim 1, wherein the case has a bottom surface portion on which the coil is fixed in the peripheral wall portion and which is arranged to close one end of the peripheral wall portion and which has a communication portion formed that connects the inside and outside of the case.

9. The vibration actuator according to claim 1, wherein the case has a lid portion that is arranged to close the other end of the peripheral wall portion and has a communication portion formed therein that connects the inside and outside of the case.

10. The vibration actuator according to claim 8, wherein a substrate is placed on one end face of the bottom portion, and the substrate is connected to the coil wires of the coil that are led out from the communication portion.

11. The vibration actuator according to claim 8, wherein the bottom portion and the peripheral wall portion are integrally formed.

12. The vibration actuator according to claim 4, wherein the sliding portion is fitted onto and fixed to the weight in the axial direction.

13. An electronic device equipped with the vibration actuator described in claim 1.

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