Vibration actuator and electric device

Abstract

This vibration actuator includes: a movable body that has a disk-shaped magnet at the center thereof and has joining parts on the front surface side and the rear surface side of the magnet in an axial direction; a cylindrical fixed body that accommodates the movable body and has a coil disposed on the radially outer side of the movable body and a cylindrical yoke surrounding the coil; and a pair of elastic support parts that support the movable body so as to be capable of reciprocating vibration in a vibration direction along the axial direction, are joined to the fixed body at outer peripheral parts thereof, and are joined to joining parts at inner peripheral parts thereof. The yoke has a shape that reduces a magnetic attraction force generated between the yoke and the magnet in accordance with the position of the movable body in the vibration direction, so as to linearize a change in the magnetic attraction force during the reciprocating vibration.

Description

Vibration actuator and electrical device

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

[0002] Generally, an actuator (vibration actuator) as a vibration source is mounted on an electrical device having a vibration function. By driving the vibration actuator to transmit vibration to the user for the user to feel, the electrical device can apply a stimulus, notify an incoming call, or improve the operation feeling and a sense of presence. Note that the electrical device includes a portable game terminal, a controller (such as a game pad) of a stationary game machine, a portable communication terminal such as a mobile phone or a smart phone, a portable information terminal such as a tablet PC (Personal Computer), and the like. In addition, the electrical device includes various health care devices and beauty devices that give a massage or the like to the user.

[0003] As an example of a conventional vibration actuator, it has a coil disposed inside a cylindrical case, a mover having a permanent magnet, and an elastic support member that supports the mover axially movably inside the coil (see, for example, Patent Document 1 and Patent Document 2). In such a vibration actuator, when a current of a predetermined frequency is passed through the coil, the mover reciprocates, that is, vibrates, due to the driving force of a voice coil motor constituted by the coil and the permanent magnet, and the vibration is output from the vibration actuator to the outside.

[0004] Japanese Patent Application Laid-Open No. 2020-54018, Japanese Patent No. 6750825

[0005] By the way, as the product on which the vibration actuator is mounted is miniaturized, it is desired to be miniaturized while ensuring high output. Along with miniaturization, the movable body is also lightened, and when the movable body vibrates at a low resonance frequency, it is desirable to generate good vibration in a wide band.

[0006] An object of the present invention is to provide a vibration actuator and an electrical device that can be miniaturized and generate suitable vibration in a wide band at a low resonance frequency.

[0007] One aspect of the vibration actuator of the present invention comprises: a movable body having a disc-shaped magnet in the center and joints on the axial front and back sides of the magnet; a cylindrical fixed body housing the movable body, the fixed body having a coil arranged radially outward from the movable body and a cylindrical yoke surrounding the coil; and a pair of elastic support parts that support the movable body so as to be able to reciprocate in a vibration direction along the axial direction, with the outer circumference of the elastic support part being joined to the fixed body and the inner circumference of the elastic support part being joined to the joint part, wherein the yoke has a shape that reduces the magnetic attractive force generated between it and the magnet according to the position of the movable body in the vibration direction, so as to linearize the change in magnetic attractive force during reciprocating vibration.

[0008] One embodiment of the electrical device of the present invention adopts a configuration that includes a vibration actuator as described above.

[0009] According to the present invention, vibration actuators and electrical equipment can be miniaturized, and suitable vibrations with a wide bandwidth and low resonant frequency can be generated.

[0010] Figure 1 is an external perspective view of a vibration actuator according to one embodiment of the present invention. Figure 2 is a front view of the vibration actuator. Figure 3 is a cross-sectional view taken along line A-A in Figure 2. Figure 4 is an exploded perspective view of the main components of the vibration actuator. Figure 5 is an exploded perspective view of the movable body shown in Figure 4. Figure 6A is a front view of the coil holding part to which the outer yoke is attached, and Figure 6B is a perspective view showing the outer yoke shown in Figure 6A. Figure 7 is an enlarged view of portion X in Figure 3. Figure 8 is a diagram illustrating the magnetic spring in the vibration actuator of this embodiment, where Figure 8A shows the relationship between the movable body position in the non-moving state and the magnetic spring, and Figure 8B shows the relationship between the movable body position in the moving state and the magnetic spring. Figure 9 shows a cylindrical outer yoke as a reference example. Figure 10 illustrates the magnetic spring in a vibration actuator having a cylindrical outer yoke. Figure 10A shows the relationship between the movable body position in a non-movable state and the magnetic spring using the cylindrical outer yoke shown in Figure 9, and Figure 10B shows the relationship between the movable body position in a movable state and the magnetic spring in the same vibration actuator. Figure 11 illustrates the relationship between the movable body position of the outer yoke and the magnetic spring in a vibration actuator. Figure 12 illustrates the magnetic circuit configuration and operation of the same vibration actuator. Figure 13 illustrates the relationship between magnetic attraction force and spring in this embodiment. Figure 13A shows the relationship between the spring reaction force and amplitude of a spring with strong nonlinearity and a spring with weak nonlinearity, and Figure 13B shows the relationship between the G value (acceleration) and resonant frequency of a spring with strong nonlinearity and a spring with weak nonlinearity. Figure 14 is a front view showing a modified example 1 of the outer yoke. Figure 15A is a front view showing a modified example 2 of the outer yoke, and Figure 15B is a front view showing a modified example 3 of the outer yoke. Figure 16A is a front view showing modified outer yoke 4, and Figure 16B is a front view showing modified outer yoke 5. Figure 17 is a front view showing modified outer yoke 6. Figure 18A is a front view of the coil holding section with modified outer yoke 7 attached, and Figure 18B is a perspective view showing the outer yoke of Figure 18A.Figure 19A is a front view of the coil holding part with modified outer yoke 8 attached, and Figure 19B is a perspective view showing the outer yoke of Figure 19A. Figure 20 is an external perspective view of a vibration actuator according to another embodiment of the present invention. Figure 21 is a cross-sectional view taken along line B-B in Figure 20. Figure 22 is an exploded perspective view of the main components of a vibration actuator according to another embodiment of the present invention. Figure 23 is an enlarged view of the Y portion of Figure 21. Figure 24 is an enlarged view of the Z portion of Figure 21. Figure 25 is a longitudinal cross-sectional view of the main components of a vibration actuator of another embodiment. Figure 26 is an exploded perspective view of the movable body in Figure 25. Figure 27 is a diagram showing an example of the vibration actuator being mounted on electrical equipment. Figure 28 is a diagram showing an example of the vibration actuator being mounted on electrical equipment.

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0012] [Overall Configuration of Vibration Actuator] Figure 1 is an external perspective view of a vibration actuator according to one embodiment of the present invention, Figure 2 is a front view of the vibration actuator, and Figure 3 is a cross-sectional view taken along line A-A in Figure 2. Figure 4 is an exploded perspective view of the main components of the vibration actuator, and Figure 5 is an exploded perspective view of the movable body shown in Figure 4.

[0013] In this embodiment, the terms "upper" and "lower" are merely added for ease of understanding and refer to the axial direction of the movable body in the vibration actuator, i.e., the direction of vibration. In other words, when the vibration actuator is mounted on electrical equipment (for example, the electronic equipment shown in Figures 27 and 28), the orientation (upper and lower) may be reversed or reversed (left and right).

[0014] The vibration actuator 1 is implemented as an electrical device in electronic devices such as portable game terminals (see Figure 27) as a vibration source, realizing the vibration function of the electronic device. This electronic device also includes portable devices such as smartphones (see Figure 28). 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.

[0015] As shown in Figures 1 to 4, the vibration actuator 1 is a columnar vibrating body, and is formed, for example, in a cylindrical shape.

[0016] The vibration actuator 1 is constructed by movably housing a movable body 20 having a magnet 22 inside, and attaching a cover 3 and a bracket 6 to the upper and lower ends of a coil holder 40 on which coils 51 and 52 are mounted, with elastic support parts 81 and 82 interposed between them. The coil holder 40 on which coils 51 and 52 are mounted, the movable body 20 positioned inside the coil holder 40, and the elastic support parts 81 and 82 connecting the upper and lower ends of the coil holder 40 to the movable body, are also referred to as the actuator body.

[0017] The vibration actuator 1 is formed as a covered cylindrical body. The vibration actuator 1 is formed to correspond to the shape of the mounting position of the electrical equipment on which the vibration actuator 1 itself is mounted. The vibration actuator 1 is not limited to a covered cylindrical body configuration; it may be formed to close both the upper and lower ends of the fixed body 2, or it may have an open shape at both the upper and lower ends.

[0018] The lid portion 3 closes the upper opening of the fixed body 2 and restricts the movement of the movable body 20 inside the fixed body 2 beyond the range in which the elastic support portion 81 can be elastically deformed when it moves in the axial direction. A notch 32 opening downward is formed in the outer cylindrical portion of the lid portion 3, and the notch 32 engages with the terminal block portion 464 on which the terminal portion 5 protrudes radially outward.

[0019] The bracket 6 is annular in shape and fits onto the lower end of the fixed body 2. The bracket 6 has an annular rib 64 that protrudes inward from the lower end of the bracket outer circumference 62, which is positioned on the outer circumference of the lower end of the fixed body 2. The bracket 6 is attached to the fixed body 2 such that the rib 64 sandwiches the outer circumference of the elastic support portion 82 between itself and the lower end of the coil holding portion 40 included in the fixed body 2, surrounding the opening at the lower end of the fixed body 2. The bracket 6 is formed to correspond to the shape of the mounting position of the electronic device on which the vibration actuator 1 is mounted.

[0020] As shown in Figures 3 and 4, the fixed body 2 has a cylindrical coil holding portion 40 in which the movable body 20 is arranged. The fixed body 2 has a pair of coils 51 and 52 arranged on the outer circumference of the magnet 22 of the movable body 20, and an outer yoke 70 that covers the coils 51 and 52 on its outer circumference. The elastic support portions 81 and 82 are attached so as to cover both openings (opening ends 461 and 471) of the coil holding portion 40.

[0021] In the fixed body 2, the movable body 20 is arranged inside the coil holding portion 40 so as to be able to reciprocate in the axial direction, which is the direction of vibration, via plate-shaped elastic support portions 81 and 82. The reciprocating movement of the movable body causes the vibration actuator 1 itself to function as a vibrating body.

[0022] <Movable body 20> As shown in Figures 3 to 5, the movable body 20 is a columnar body positioned within the coil holding portion 40. Within the coil holding portion 40, the movable body 20 is connected to the inner circumference 802 of the elastic support portions 81 and 82 at both ends (upper and lower ends) that are spaced apart in the axial direction, i.e., the vibration direction.

[0023] The movable body 20 is supported so as to be able to reciprocate in the axial direction along the inner circumferential surface 42a of the coil holding portion 40. The movable body 20 may be formed in the shape of a cylinder or a polygonal shape that approximates a cylinder, and it is preferable that the movable body 20 has a shape that makes it easy to create a gap of a constant width around its entire circumference between it and the inner circumferential surface 42a of the coil holding portion 40 (cylindrical main body portion 42). The outer circumferential surface 20a of the central part of the movable body 20 faces the inner circumferential surface 42a of the coil holding portion 40 over the entire range of motion of the movable body 20, and has a length such that both ends protrude in the axial direction longer than both ends of the inner circumferential surface 42a.

[0024] When the coils 51 and 52 are not energized, the movable body 20 has a disc-shaped magnet 22 positioned in the axial center of the fixed body 2, that is, opposite to the axial center of the coils 51 and 52.

[0025] The movable body 20 has a pair of connecting sleeves (connecting parts) 26a and 26b, respectively, which are arranged on the axial front and back sides of the magnet 22, and a pair of yokes (yokes 24a and 24b) which are arranged between the magnet 22 and the pair of connecting sleeves 26a and 26b.

[0026] In this embodiment, the magnet 22 is positioned in the center of the movable body 20 in the direction of vibration, which is the axial direction of the movable body 20, that is, at the center of the movable body 20. In the movable body 20, the yokes 24a and 24b and the connecting sleeves 26a and 26b are stacked in order on both sides of the vibration direction of the magnet 22 (the front surface 22a side and the back surface 22b side shown in Figure 3), respectively, in symmetrical positions around the magnet 22.

[0027] The magnet 22, yokes 24a and 24b, together with the coils (a pair of coils 51 and 52) and the outer yoke (yoke) 70, constitute a magnetic circuit that drives the movable body 20 with the axial direction of the pair of coils 51 and 52 (the magnetization direction of the magnet 22) as the direction of vibration.

[0028] In the movable body 20, the outer diameters of the magnet 22, the yokes 24a and 24b, and the connecting sleeves 26a and 26b, respectively, are configured to be the same diameter or approximately the same diameter.

[0029] The outer circumferential surfaces of the joint body 262 of the magnet 22, yokes 24a and 24b, and joining sleeves 26a and 26b constitute an outer circumferential surface 20a that is flat in the axial direction. As a result, in the movable body 20, the outer circumferential surface 20a facing the inner circumferential surface 42a of the coil holding portion 40 is flush or nearly flush, and has a flat circumferential surface without irregularities.

[0030] The movable body 20 may be configured in any way as long as it has a magnet and is movable in the axial direction via an elastic support portion relative to the cylindrical fixed body 2 which has a coil and an outer yoke.

[0031] The outer diameters of both ends of the movable body 20 (for example, the spring joints 266 of the connecting sleeves 26a and 26b) are smaller than the outer diameter of the central part of the movable body (magnet 22, etc.). When the movable body is not in motion, the ends with smaller outer diameters are positioned to protrude vertically in the axial direction from the upper and lower ends of the inner circumferential surface 42a of the coil holding part 40 (cylindrical main body part 42), that is, they are positioned outward in the vibration direction from both ends of the inner circumferential surface 42a of the coil holding part 40 in the vibration direction.

[0032] Furthermore, when the movable body 20 is at the maximum amplitude position on both sides in the vibration direction, one of the connecting sleeves 26a and 26b is configured to be located outside the range where it faces the outer yoke 70 in the radial direction.

[0033] <Magnet 22> The magnet 22 is a solid disc-shaped body (including columnar bodies) and is magnetized in the axial direction (vibration direction). In the magnet 22, the front and back surfaces 22a and 22b, which are separated in the vibration direction, each have different polarities. For example, the front surface 22a has a north pole and the back surface 22b has a south pole.

[0034] In this embodiment, the magnet 22 has a diameter (width) that is greater than its length (height) in the direction of vibration. The magnet 22 may be processed with recesses or other features, but if it is a solid cylindrical shape, it can be manufactured at a lower cost compared to a magnet with recesses or other processing. The magnet 22 is, for example, a neodymium sintered magnet.

[0035] The magnet 22 is positioned at a distance from the coil (a pair of coils 51, 52) on the radially inner side of the coil (a pair of coils 51, 52). Here, "radial direction" also refers to the direction perpendicular to the axial direction (vibration direction) of the coil (a pair of coils 51, 52). The magnet 22 is positioned such that the center position in the vibration direction on its radially outer surface and the center position in the vibration direction on the inner circumferential surface 42a of the coil holding portion 40 are opposite each other in the radial direction.

[0036] The magnet 22 may be cylindrical, plate-shaped, or any other shape other than a solid columnar shape, as long as it is positioned inside the coils 51 and 52 with its two magnetization surfaces facing the direction of extension of the coils 51 and 52's axes. Furthermore, it is desirable that the axial center of the magnet 22 coincides with the axial center of the movable body 20.

[0037] <Yoke 24a, 24b> The yokes 24a and 24b are magnetic materials and are arranged on the front and back surfaces 22a and 22b of the magnet 22, respectively. The yokes 24a and 24b are fixed to the magnet 22 by attraction to it. The yokes 24a and 24b may be joined to the front and back surfaces 22a and 22b of the magnet 22 by bonding, for example, with a thermosetting adhesive such as epoxy resin or an anaerobic adhesive. The yokes 24a and 24b are formed in the shape of a plate (or column) with thickness in the axial direction, for example, in the shape of a disc with the same diameter as the magnet 22, and each has an outer surface that is flush with the outer surface of the magnet 22. In this embodiment, the yokes 24a and 24b are members of the same shape formed in the same way.

[0038] The yokes 24a and 24b concentrate the magnetic flux of the magnet 22, allowing it to flow efficiently without leakage, and effectively distribute the magnetic flux between the magnet 22 and the outer yoke 70, and between the magnet 22 and the coils (a pair of coils 51 and 52). Preferably, the yokes 24a and 24b are made of a metallic magnetic material such as SECC (bonderized steel sheet).

[0039] Furthermore, the yokes 24a and 24b may function not only as part of the magnetic circuit but also as weights. In addition, the yokes 24a and 24b have the function of positioning the joining sleeves 26a and 26b relative to the magnet 22 by aligning their outer diameters when joining the joining sleeves 26a and 26b which have the same outer diameter.

[0040] When the movable body 20 is not moving, it is preferable that the yokes 24a and 24b are positioned inside (radially inward) of the pair of coils 51 and 52, in a direction perpendicular to the vibration direction, and facing the center of the vibration direction of the pair of coils 51 and 52.

[0041] Further, in the present embodiment, it is preferable that the height position of the upper surface of the yoke (yoke 24a) above the magnet 22 is located below (center side) the position of the upper end of the upper coil 51. In addition, it is preferable that the height position of the lower surface of the yoke (yoke 24b) below the magnet 22 is located above (center side) the position of the lower end of the lower coil 52. With this configuration, the yokes 24a and 24b, together with the magnet 22, the coils 51 and 52, and the outer yoke 70, constitute a suitable magnetic path with less magnetic flux leakage and high magnetic efficiency.

[0042] <Bonding sleeves 26a and 26b> The bonding sleeves 26a and 26b bond the movable body 20, specifically the magnetic force generating portion (magnet 22 and yokes 24a and 24b), to the elastic support portions 81 and 82. The bonding sleeves 26a and 26b are provided so as to sandwich the yokes 24a and 24b in the axial direction together with the magnet 22 in the vibration direction (magnetization direction of the magnet 22). The bonding sleeves 26a and 26b are formed into a shape such that the weight of the movable body 20 becomes a desired weight. The bonding sleeves 26a and 26b are formed in a cylindrical shape, but are not limited thereto, and may be formed in a frustum of a cone shape, a polygonal frustum shape, or a polygonal shape.

[0043] The bonding sleeves 26a and 26b are arranged symmetrically in the vibration direction with respect to the center in the vibration direction in the movable body 20.

[0044] The bonding sleeves 26a and 26b are preferably made of, for example, aluminum and formed of a non-magnetic material. If the bonding sleeves 26a and 26b are made of a non-magnetic material, it is possible to suppress the increase (expansion) of the magnetic circuit configuration in the vibration direction and configure the magnetic circuit compactly. Note that the bonding sleeves 26a and 26b may be made of a material with a high specific gravity.

[0045] The joining sleeves 26a and 26b have a gradient portion 264 between a joint body 262 joined to the yokes 24a and 24b and spring joint portions 266 joined to the elastic support portions 81 and 82, respectively. The gradient portion 264 is a part for adjusting the weights of the joining sleeves 26a and 26b. Note that the pair of joining sleeves 26a and 26b have the same shape and are similarly configured.

[0046] In the joining sleeves 26a and 26b, the joint body 262, the gradient portion 264, and the spring joint portion 266 are continuously formed in the axial direction and have the same axis. The outer diameter of the joint body 262 is the same as or substantially the same as the outer diameters of the yokes 24a and 24b.

[0047] Since the outer diameters of the spring joint portions 266 and the gradient portion 264 at both ends of the movable body 20 are smaller than the outer diameter of the central portion, when the movable body 20 moves axially due to the deformation of the elastic support portions 81 and 82, escape portions of the deformed elastic support portions 81 and 82 are formed. Thereby, interference between the movable body 20 that moves and the elastic support portions 81 and 82 is avoided, and a movable region of the movable body 20 is preferably secured, and vibration can be output with a high amplitude. The spring joint portions 266 are joined to the elastic support portions 81 and 82 by caulking, using an adhesive, or the like.

[0048] A groove portion 268 is formed on the tip surface of the spring joint portion 266. When joining in a state where the protruding end of the spring joint portion 266 is inserted into the opening of the inner peripheral portion 802, the inner peripheral portion 802 is placed on the tip surface, so that the groove portion 268 becomes an adhesive reservoir when an adhesive is used when joining the joining sleeves 26a and 26b and the elastic support portions 81 and 82. Note that the joining sleeves 26a and 26b and the elastic support portions 81 and 82 are joined (fixed to each other) by caulking the spring joint portions 266 to the inner peripheral portion 802, but they may be joined to each other by a method combining welding, adhesion, and caulking.

[0049] <Coil holding portion 40> FIG. 6A is a front view showing a fixed body with the lid portion and the bracket removed, and FIG. 6B is a perspective view showing the outer yoke 70 shown in FIG. 6A.

[0050] The coil holding portion 40 shown in Figures 3, 6A, and 6B is formed in a cylindrical shape and holds a pair of coils 51 and 52 arranged on its outer circumferential surfaces 421 and 422, and an outer yoke 70 that covers the coils 51 and 52. The coil holding portion 40 is fitted with terminal portions 5 for energizing the coils 51 and 52, and supports the internal movable body 20 so that it can move freely via elastic support portions 81 and 82.

[0051] The coil holder 40 is a non-magnetic material and is formed from a resin such as phenolic resin or polybutylene terephthalate (PBT). In this embodiment, the coil holder 40 is formed from a material containing phenolic resin such as highly flame-retardant bakelite, and because it has high dimensional accuracy, the positional accuracy of the pair of coils 51 and 52 can be improved, and variations in vibration characteristics can be reduced.

[0052] The coil holding portion 40 has a cylindrical main body portion 42 positioned on the inner circumference of the coil 51, and flange portions 44, 46, and 47 are provided on the outer circumferential surface of the cylindrical main body portion 42, extending radially outward at predetermined intervals in the axial direction.

[0053] The coil holding portion 40 is formed in the shape of a coil bobbin that holds the coils 51 and 52, by a cylindrical body portion 42 and flange portions 44, 46, and 47. The coil holding portion 40 has concave coil arrangement portions 401 and 402 on the outer surface of the cylindrical body portion 42 and between the flange portions 44, 46, and 47, in which a pair of coils 51 and 52 are respectively arranged.

[0054] The cylindrical body portion 42 is cylindrical in shape, located radially inward of the pair of coils 51 and 52, and has an inner circumferential surface 42a that faces the outer circumferential surface 20a of the movable body 20 with a gap D between them. The inner circumferential surface 42a is the inner circumferential surface of the fixed body 2. The inner circumferential surface 42a is a flat surface without irregularities in the axial direction (vibration direction), and the gap D is maintained at a constant width in the axial direction whether the movable body 20 is moving or not. The gap D is a distance that allows the movable body 20 to move without contact between the outer circumferential surface 20a and the inner circumferential surface 42a when the movable body 20 moves in the vibration direction.

[0055] The cylindrical main body portion 42 is positioned between the pair of coils 51 and 52 and the magnet 22, and functions as a protective wall that prevents contact between the magnet 22 and the pair of coils 51 and 52.

[0056] The coil arrangement sections 401 and 402 open radially outward from the outer peripheral surfaces 421 and 422 of the cylindrical main body 42, and are formed along the outer circumference with the outer peripheral surfaces 421 and 422 of the cylindrical main body 42 as the bottom surface.

[0057] A pair of coils 51 and 52 are arranged in a wound state in the concave coil arrangement sections 401 and 402. The pair of coils 51 and 52 are positioned to accommodate the magnetic force generating section (magnet 22 and yokes 24a and 24b) which are spaced apart in the axial direction. Preferably, the axial centers of coils 51 and 52 are positioned opposite the upper end surface of yoke 24a and the lower end surface of yoke 24b.

[0058] Of the flange portions 44, 46, and 47, the central flange portion 44 is configured to have a smaller outer diameter than the outer circumference of the flange portions 46 and 47, and the outer surface of the flange portion 44 is positioned recessed compared to the outer end faces of the flange portions 46 and 47. In addition, a notch 441 is formed in the flange portion 44, in which coil wires connecting the coils 51 and 52 are placed.

[0059] The outer yoke 70 is positioned to cover the outer circumferential surfaces of the flange portions 44, 46, and 47 and the coils 51 and 52 from the radially outer side. The flange portions 44, 46, and 47 hold the outer yoke 70 with their outer circumferential surfaces.

[0060] The flange bodies 462 and 472 of the flange portions 46 and 47 are formed in a cylindrical shape with openings in directions that move away from the central flange portion 44, for example, in the vertical direction. The elastic support portions 81 and 82 are fixed to the flange portions 46 and 47 via engaging projections 48 provided at the opening ends, i.e., the upper and lower ends.

[0061] In the flange portion 46, a guide notch 467 is provided in the terminal block portion 464 on which the terminal portion 5 is arranged, which guides the winding in an engageable manner. In the terminal block portion 464, a guide groove portion 468 is formed between the two terminal portions 5, opening in the axial direction, and the guide groove portion 468 guides the winding from the terminal portion 5 to the coils 51 and 52 in the coil arrangement portions 401 and 402.

[0062] The terminal block portion 464 is formed to protrude radially outward from the outer circumferential surface of the annular flange body 462 of the flange portion 46. The terminal block portion 464 is formed, for example, as a rectangular parallelepiped with its width parallel to the tangent to the outer circumference of the flange portion 44. Terminal portions 5 are provided protruding from each of the end faces (protruding end faces) of the terminal block portion 464.

[0063] The terminal block section 464 has a recessed portion (press-fitting space component) for fixing the terminal section 5, so the terminal section 5 can be firmly held and can be stably fixed when the terminal section 5 is assembled to the coil holding section 40.

[0064] Each of the pair of terminal portions 5 is a conductive pin-shaped terminal and is provided protruding from the non-magnetic terminal block portion 464. The terminal portions 5 are arranged so that their base ends are embedded in the flange portion 46 and their tip ends protrude. The terminal portions 5 may be provided in the flange portion 46 by press-fitting, or they may be provided in the flange portion 46 by insert molding into the coil holding portion 40.

[0065] Terminal section 5 functions as a connector connection section for connecting to external equipment. Terminal section 5 connects coils 51 and 52 to external equipment that functions as an AC power supply unit (other than the main body of the vibration actuator, for example, a power supply unit such as a drive control unit), enabling the supply of power (for example, AC voltage, etc.) from the external equipment to coils 51 and 52. As a result, the pair of coils 51 and 52 can generate thrust between themselves and the magnet, allowing them to move toward and away from each other in their respective axial directions. Note that terminal section 5 connects the windings at both ends of a single winding that constitutes each coil 51 and 52 by intertwining them.

[0066] In the coil holding section 40, the windings of the coil terminals connected to the terminal section 5 are routed through the guide notches 467 to the inner circumferential surface of the flange section 46, and then connected to the coil 51 through the guide grooves 468. When the coil 51 (52) is arranged by winding the windings within the coil arrangement section 401 (402), the windings of the terminals connected to the terminal section 5 will be pulled. However, the windings that are pulled are hooked onto the guide notches 467, the corners of the terminal block section 464, and the corners on the back side of the flange section 46, etc., and their direction of extension is changed before reaching the terminal section 5, so the pulling force is not transmitted to the terminal section 5 itself. As a result, the terminal section 5 is not subjected to any pulling force acting on the windings via the windings.

[0067] The engaging projection 48 positions the fixed body 2 radially and in the vibration direction relative to the lid 3 and bracket 6, and also positions the elastic support portions 81 and 82 that are sandwiched between the fixed body 2 and the lid 3, and between the fixed body 2 and the bracket 6, in the radial direction.

[0068] The engaging projection 48 is provided projecting in the direction of vibration (vertical direction) at the upper and lower ends of the coil holding portion 40, that is, at the upper and lower annular opening ends 461 and 471 of the flange portions 46 and 47 (referred to as "openings of the coil holding portion 40," respectively).

[0069] The engaging projections 48 engage with the recesses in the lid 3 and the bracket 6, respectively. Multiple engaging projections 48 are provided at equal intervals around the axis of the coil holding portion 40, corresponding to the recesses in the lid 3 and the bracket 6.

[0070] <Coils 51, 52> The pair of coils 51 and 52 are energized when the unit is in motion (vibrating) and together with the magnet 22, they constitute a voice coil motor. The pair of coils 51 and 52 are positioned symmetrically with respect to the magnet 22 in the direction of vibration with respect to the movable body 20 which has the magnet 22, yoke 24a and yoke 24b, etc.

[0071] It is preferable that the center position of the length of coils 51 and 52 in the direction of vibration, that is, the center position of the length between the upper end of coil 51 and the lower end of coil 52, is the same position (including approximately the same position) in the direction of vibration as the center position of the length of the movable body 20 (especially the magnet 22) in the direction of vibration.

[0072] Furthermore, coils 51 and 52 are constructed by winding the wire of a single coil in opposite directions to each other, and when energized, current flows in opposite directions through coils 51 and 52.

[0073] <Elastic support parts 81, 82> The elastic support parts 81 and 82 shown in Figures 3 and 4 support the movable body 20, which is located inside the coil holding part 40, so that it can reciprocate relative to the coil holding part 40 in the vibration direction. The elastic support parts 81 and 82 are mounted parallel to each other across the openings, which are the separated ends (upper and lower ends) of the coil holding part 40 in the vibration direction, and across the ends (upper and lower ends) of the movable body. The elastic support parts 81 and 82 bias the movable body 20 to be located in the axial center position (default position).

[0074] The elastic support parts 81 and 82 are spiral-shaped springs formed in a disc shape, with an annular inner circumference 802 which is the inner spring end and an annular outer circumference 804 which is the outer spring end, joined together by a deformable arm 806 which is an arc shape in plan view and is elastically deformed and arranged in a spiral shape.

[0075] Due to the deformation of the deformable arm 806, the elastic support portions 81 and 82 are displaced relatively in the axial direction, with the inner circumference 802 and the outer circumference 804 being displaced.

[0076] The pair of elastic support parts 81 and 82 are identical members having similar configurations. In this embodiment, the pair of elastic support parts 81 and 82 are arranged so that the direction of rotation of the vortex is the same, but they may also be arranged so that they are opposite to each other.

[0077] The inner circumference 802 has a connecting hole located in the center of the elastic support portions 81 and 82, into which the tip of the spring joint portion 266 of the movable body 20 is fitted and joined.

[0078] The outer periphery 804 is fixed to the upper and lower ends of the coil holding portion 40, that is, the open ends 461 and 471 of the flange portions 46 and 47, with the engaging projection 48 engaged in the positioning recess 809, for example by bonding with an adhesive. The outer periphery 804 may also be fixed in a state where it is positioned with the engaging projection 48 engaged in the positioning recess 809, and is sandwiched between the open ends 461 and 471, the internal stepped portion 4a of the lid portion, and the internal stepped portion 6a of the rib 64 of the bracket 6.

[0079] The elastic support parts 81 and 82 are made of thin, flat, disc-shaped spiral springs formed from phosphor bronze, which has high workability, excellent corrosion resistance, and high tensile strength and wear resistance. However, they can be made from any material that is elastically deformable. Furthermore, if they are made from a non-magnetic material such as phosphor bronze, the flow of magnetic flux in the magnetic circuit will not be disturbed at all. In this embodiment, the pair of elastic support parts 81 and 82 may be joined to the coil holding part 40 and the movable body 20 in a direction in which the spiral direction is the same.

[0080] <Outer Yoke 70> As described above, the outer yoke 70, together with the pair of coils 51 and 52, constitutes the magnetic circuit on the stationary side, and together with the magnetic circuit on the movable side, that is, the magnet 22, yoke 24a, and yoke 24b, constitutes the magnetic circuit.

[0081] The outer yoke 70 has a shape that reduces the magnetic attractive force generated between it and the magnet 22 according to the position of the movable body 20 in the direction of vibration, so as to linearize the change in magnetic attractive force during reciprocating vibration. The outer yoke 70 is configured such that, for example, the magnetic spring formed with the magnet 22 is dampened when the reciprocating magnet 22 moves away from the central part 72 of the outer yoke 70.

[0082] Furthermore, the outer yoke 70 has as few holes as possible, and when configured as part of the magnetic circuit, it increases the efficiency of the magnetic circuit and enables strong vibration over a wide frequency range. Also, because it has no holes, the movable body 20 moves parallel to the direction of vibration, and the outer diameter of the movable body 20 is less likely to come into contact with the inner diameter of the coil holding part 40. As a result, the gap between the magnet 22 and the coils 51 and 52 of the coil holding part 40 can be reduced, and strong vibration can be obtained over a wide frequency range.

[0083] The outer yoke 70 is a cylindrical magnetic material and, as shown in Figures 1 to 6, is positioned to surround the outer circumferential surface of the coil holding portion 40 and to cover the pair of coils 51 and 52 radially outward. When the coils 51 and 52 are not energized, that is, when the movable body 20 is not driven, the outer yoke 70 is positioned on the coil holding portion 40 such that its axial central portion 72 faces the axial central portion of the magnet 22 (see Figure 3) in a direction perpendicular to the axial direction.

[0084] The outer yoke 70 is configured such that the magnetic attractive force between the magnets 22 and the outer yoke 70 decreases as the magnets 22, which are facing each other on the inner circumferential surface, move away from the central part 72 of the outer yoke 70 towards both ends along the axial direction.

[0085] In other words, the magnetic spring formed by the outer yoke 70 together with the magnet 22 that moves in the axial direction of the outer yoke 70 is strongest when the magnet 22 faces each other at the central part 72, and weaker at both ends than at the center.

[0086] The outer yoke 70 is, for example, a cylindrical body made of a magnetic material, and has a cylindrical central portion 72 and magnetic reduction portions 74 and 76 which are cylindrical ends that are continuous on both sides of the central portion 72 in the axial direction. The magnetic reduction portions 74 and 76 reduce the magnetic attractive force generated between them and the magnet 22, so as to linearize the change in magnetic attractive force during reciprocating vibration.

[0087] The outer yoke 70 is configured such that the magnetic attraction force generated between the magnet 22 and the magnet 22 is large at the central portion 72, and decreases as it moves towards the magnetic reduction portions 74 and 76.

[0088] The outer yoke 70 has a shape, for example, with both ends widened (drum shape, hourglass shape), and the opening diameters at both axial ends gradually widen compared to the opening diameter of the central part 72. The outer yoke 70 is configured such that the outer diameters of the magnetic reduction parts 74 and 76 gradually increase as they move away from the central part 72.

[0089] Figure 7 is an enlarged view of portion X in Figure 3. The magnetic reduction sections 74 and 76 are formed to bend and widen toward the opening side from the ends 742 and 762 that are connected to both ends of the central section 72.

[0090] The ends 742 and 762 (end 742 is shown in Figure 7) are located axially outward (away from the movable body magnetic part in the axial direction) than each of the ends of the magnetic force generating section (movable body magnetic section), which is the magnetic circuit of the movable body 20 when it is not in motion. In Figure 7, the end 742 of the magnetic reduction section 74 is located on one end (upper end) side of the movable body 20 than the end face (surface) 242 of the yoke 24a. On the other hand, the end 762 of the magnetic reduction section 76 (see Figure 3) is located on the other end side of the movable body 20 than the end face (surface) 244 of the yoke 24b.

[0091] In the magnetic reduction sections 74 and 76, the ends 742 and 762 where the bending begins from the central section 72, that is, the constriction start position KK of the outer yoke 70, are positioned axially outward from each of the ends of the movable magnetic section (see end position KJ).

[0092] In other words, the magnetic reduction units 74 and 76 do not overlap with the movable magnetic unit in the axial direction when the movable magnetic unit is in a non-driving state, and are positioned to surround the movable magnetic unit at the central part 72, and are positioned to face each other radially when the movable magnetic unit moves.

[0093] The positions of the magnetic reduction sections 74 and 76 are set based on the range of motion of the movable body. For example, the length L (see Figure 3) between the ends 742 and 762 of the magnetic reduction sections 74 and 76 is preferably greater than or equal to the axial length R of the movable body magnetic section, which becomes the magnetic force generating section of the movable body 20 when the movable body 20 is not moving. The axial length R of the movable body magnetic section is the axial length R of the magnet 22 and the yokes 24a and 24b, which are arranged on the front and back surfaces 22a and 22b of the magnet 22, respectively. Furthermore, it is preferable that L is R × 1.0 to 1.2. In other words, L = R × 1.0 to 1.2.

[0094] The outer yoke 70 is a conductive plate-shaped material, with engaging portions 70a (dovetail grooves) and engaged portions 70b (dovetail joints) formed at both ends to engage with each other. As a result, the outer yoke 70 is positioned to surround the coil holding portion 40 from the outer circumference, and is arranged as a cylindrical body with an outer diameter that widens at the upper and lower ends.

[0095] The outer yoke 70 is fitted into a notched engagement portion 469 (for example, the lower part of the terminal block portion 464) formed in the coil holding portion 40 at a portion of its upper end (the tip of the magnetic reduction portion 74) 70c (see Figure 3). This allows the outer yoke 70 to be positioned axially relative to the coil holding portion 40.

[0096] The outer yoke 70 is positioned in the coil holding portion 40 so that its inner surfaces abut against the outer surfaces (for example, outer surfaces 46a, 47a) of the upper and lower flange portions 46, 47. The outer surfaces 46a, 47a are configured as tapered surfaces that are inclined in accordance with the shape (inclination) of the magnetic reduction portions 74, 76. The outer yoke 70 is fitted into the concave portion formed by the lid portion 3, the bracket 6, the upper and lower flange portions 46, 47 and the central flange portion 44 of the coil holding portion 40, and covers the coils 51, 52 from the outer circumference.

[0097] The outer yoke 70 is positioned in contact with the flange portions 46 and 47, with its outer surfaces 46a and 47a having a shape corresponding to the constricted shape created by the magnetic reduction portions 74 and 76. This allows the outer yoke 70 to be easily and effectively positioned radially relative to the coil holding portion 40 having the flange portions 46 and 47.

[0098] The outer yoke 70 can increase the thrust constant in the magnetic circuit, thereby improving electromagnetic conversion efficiency.

[0099] The vertical height of the outer yoke 70 is positioned above the upper end of the coil 51 and below the height of the lower end of the coil 52. Furthermore, when the movable body 20 moves upward, the upper end of the outer yoke 70 is at the same height as or higher than the upper surface of the yoke 24a on the surface of the magnet 22 of the movable body 20, and the outer yoke 70 is radially opposite the magnetic force generating unit. Similarly, when the movable body 20 moves downward, the lower end of the outer yoke 70 is at the same height as or lower than the lower surface of the yoke 24b on the back surface of the magnet 22 of the movable body 20, and the outer yoke 70 is radially opposite the magnetic force generating unit. The outer yoke 70 is formed from, for example, SECC (electro-galvanized steel sheet), which has excellent weldability and corrosion resistance.

[0100] The outer yoke 70 can reduce the stress on the elastic support parts 81 and 82 when they are made into mechanical springs, thereby improving the durability of the elastic support parts 81 and 82.

[0101] Figure 8A shows the relationship between the movable body position in the non-moving state and the magnetic spring in the vibration actuator, and Figure 8B shows the relationship between the movable body position in the moving state and the magnetic spring in the vibration actuator. Figure 9 is a schematic diagram showing a cylindrical outer yoke as a reference example. Figure 10A is a schematic diagram showing the relationship between the movable body position in the non-moving state and the magnetic spring using the cylindrical outer yoke shown in Figure 9, and Figure 10B shows the relationship between the movable body position in the moving state and the magnetic spring in the vibration actuator using the cylindrical outer yoke. Figure 11 is a diagram used to explain the relationship between the movable body position of the outer yoke and the magnetic spring in the vibration actuator.

[0102] As shown in Figures 6A, 6B, 8A, and 8B, the outer yoke 70 is formed with a diameter wider at the upper and lower ends than at the central portion 72. The outer yoke 70 is configured such that when the movable body 20 (mainly the magnet 22) facing the inner circumferential surface moves axially from the central portion to either the upper or lower end, the distance (spacing) between the outer yoke 70 and the movable body 20 moving at each end increases. At both ends (magnetic reduction portions 74, 76), the magnetic attractive force generated between the magnet 22 and the outer yoke 70 is reduced.

[0103] As a result, the magnetic spring formed between the outer yoke 70 and the outer yoke 70, as shown in Figure 11, changes linearly.

[0104] Specifically, as shown in Figure 8A, in the non-moving state, the vibration actuator 1 has a balance between the attractive force (magnetic attraction) between the movable body 20 (magnet 22 and yokes 24a and 24b, which are magnetic force generating parts) located in the center and the outer yoke 70.

[0105] When the vibration actuator 1 is in motion, for example, when the movable body 20 is moved upward, the distance between the movable body 20 and the outer yoke 70 increases, as shown in Figure 8B. At this time, the magnetic attraction between the movable body 20 located on the upper side and the upper part of the outer yoke 70 (here, the magnetic reduction part 74) is weaker than when they are facing each other at the center. Similarly, the magnetic attraction between the movable body 20 located on the lower side and the lower part of the outer yoke 70 (here, the magnetic reduction part 76) is weaker than when they are facing each other at the center.

[0106] As a result, in the outer yoke 70 of the vibration actuator 1, as shown in Figure 11, when the movable body 20 moves in a direction perpendicular to the direction opposite to the outer yoke 70, the magnetic spring changes in a way that linearizes, so that the change in the magnetic spring becomes linear in conjunction with this movement.

[0107] On the other hand, when a cylindrical outer yoke 700, as shown in Figure 9, is used instead of the outer yoke 70 in the vibration actuator 1, as shown in Figure 10A, the tension between the outer yoke 700 and the movable body 20 is balanced in the non-moving state, similar to the case of the outer yoke 70.

[0108] However, as shown in Figure 10B, in the movable state (for example, when the movable body moves upward), the distance between the outer yoke 700 and the movable body 20, that is, the upper part of the outer yoke 700 and the movable body 20, is small, so the attraction between them is strong. Also, when the movable body moves downward, the distance between the outer yoke 700 and the movable body 20, that is, the lower part of the outer yoke 700 and the movable body 20, is small, so the attraction between them is strong. As a result, when a cylindrical outer yoke 700 is used, the configuration becomes one with a magnetic spring that has a nonlinear change, as shown in Figure 11.

[0109] <Operation of Vibration Actuator 1> The operation of the vibration actuator 1 based on its magnetic circuit configuration will be explained with reference to Figure 12. Figure 12 is a diagram illustrating the magnetic circuit configuration and operation of the vibration actuator.

[0110] The operation of the vibration actuator 1 will be explained using the example of a case where the magnet 22 is magnetized such that the surface 22a on one side in the magnetization direction (upper side in this embodiment) is the north pole, and the back surface 22b on the other side in the magnetization direction (lower side in this embodiment) is the south pole.

[0111] In the vibration actuator 1, the movable body 20 is considered to correspond to the mass portion in a spring-mass vibration model. Therefore, if the resonance is sharp (has a steep peak), the steep peak is suppressed by damping the vibration. By damping the vibration, the resonance becomes less steep, and the maximum amplitude position (maximum amplitude value) and maximum displacement of the movable body 20 at the time of resonance do not vary, resulting in the output of a vibration with a suitable and stable maximum displacement.

[0112] In the vibration actuator 1, when the coils 51 and 52 are not energized and the actuator is inactive, the magnetic flux is emitted from the surface 22a side of the magnet 22 and radiated from the yoke 24a towards the coil 51 side. The magnetic flux then passes through the outer yoke 70, through the coil 52, through the yoke 24b, and a flow of magnetic flux mf is formed, which is incident on the magnet 22 from the back surface 22b side.

[0113] Therefore, as shown in Figure 12, when current is applied, the interaction between the magnetic field of the magnet 22 and the current flowing through the coils (a pair of coils 51 and 52) generates a Lorentz force in the -f direction on the pair of coils 51 and 52 according to Fleming's left-hand rule. Since the coils (the pair of coils 51 and 52) are fixed to the fixed body 2 (coil holder 40), according to the law of action and reaction, a force opposite to this -f direction Lorentz force is generated as a thrust in the F direction on the movable body 20 having the magnet 22. As a result, the movable body 20 moves in the F direction, that is, towards the lid 3.

[0114] Furthermore, when the energizing direction of the pair of coils 51 and 52 is switched to the opposite direction and energized, a Lorentz force in the opposite direction f is generated. When a Lorentz force in the direction f is generated, according to the law of action and reaction, a force opposite to this Lorentz force in the direction f is generated as a thrust (a thrust in the -F direction) on the movable body 20, and the movable body 20 moves in the -F direction, that is, towards the bracket 6.

[0115] In the vibration actuator 1, when it is not powered and therefore inactive, as described above, magnetic attraction forces act between the magnet 22 and the outer yoke 70, and the magnet 22 and the outer yoke 70 form a magnetic spring.

[0116] The vibration actuator 1 is driven by an alternating current wave input to a pair of coils 51 and 52 from a power supply unit (for example, the drive control unit 203 shown in Figures 27 and 28). In other words, the direction of current flow to the pair of coils 51 and 52 is periodically switched, and the movable body 20 is subjected to alternating thrusts in the F direction on the lid 3 side and in the -F direction on the bracket 6 side.

[0117] As a result, the movable body 20 vibrates in the direction of vibration.

[0118] Furthermore, regarding the driving of the movable body 20 by generating a resonance phenomenon in the vibration actuator 1, for example, the driving principle is explained in Patent Document 2, using equations of motion and circuit equations. This driving principle is applicable to this embodiment.

[0119] In the vibration actuator 1, the elastic member (spring) that supports the movable body 20 so as to be able to move back and forth is composed of a mechanical spring consisting of elastic support parts (leaf springs) 81 and 82, and a magnetic spring including the outer yoke 70 and the magnet 22.

[0120] Mechanical springs are linear, while magnetic springs, in their typical cylindrical shape, are nonlinear. As vibration actuators become smaller, the weight of the moving parts decreases, and mechanical springs become softer.

[0121] In this configuration, increasing the amplitude makes the reaction force of the magnetic spring more nonlinear, and the spring of the vibration actuator 1 itself becomes nonlinear.

[0122] Figure 13A shows the relationship between spring reaction force and amplitude for strongly nonlinear and weakly nonlinear springs, while Figure 13B shows the relationship between G-value (acceleration) and resonant frequency for strongly nonlinear and weakly nonlinear springs.

[0123] As shown in Figures 13A and 13B, in the case of a spring exhibiting strong nonlinearity, the amplitude, i.e., the G value, decreases sharply after passing the resonance point K. Therefore, it is difficult to input a frequency equal to the resonance point, and the frequency bandwidth in which the desired vibration intensity can be output is narrow. In contrast, the vibration actuator 1 uses an outer yoke 70 to make the magnetic spring a linear spring. As a result, as shown in Figure 11, the spring of the vibration actuator 1 itself is linear and has weak nonlinearity, so the G value does not change sharply even after passing the resonance point K (bandwidth T). Therefore, in a vibration actuator with a low resonant frequency, the bandwidth T, i.e., the vibration characteristics near the resonance point K, can be maintained as flat characteristics. This makes it possible to obtain good vibration over a wide bandwidth.

[0124] Figure 14 is a front view showing modification 1 of the outer yoke, Figure 15A is a front view showing modification 2 of the outer yoke, and Figure 15B is a front view showing modification 3 of the outer yoke. Figure 16A is a front view showing modification 4 of the outer yoke, and Figure 16B is a front view showing modification 5 of the outer yoke. Figure 17 is a front view showing modification 6 of the outer yoke. Figure 18A is a front view of the coil holder with modification 7 of the outer yoke attached, and Figure 18B is a perspective view showing the outer yoke of Figure 18A. Figure 19A is a front view of the coil holder with modification 8 of the outer yoke attached, and Figure 19B is a perspective view showing the outer yoke of Figure 19A.

[0125] The outer yoke 70 is positioned in a cylindrical coil holding portion 40 in which a movable body 20 that moves in the axial direction is located, so as to surround the magnet 22 of the movable body 20. The outer yoke 70 is a portion that is continuously arranged on both sides of the central portion 72 in the axial direction, and can be configured in any way as long as it reduces the magnetic attractive force generated between the central portion 72 and the magnet 22 facing it, thereby linearizing the change in magnetic attractive force during the reciprocating vibration of the movable body 20.

[0126] As shown in Figure 14, the difference in the opening diameter between the magnetic reduction sections 74A and 76A and the central section 72A may be made larger compared to the outer yoke 70A.

[0127] Furthermore, as shown in the outer yoke 70B in Figure 15A and the outer yoke 70C in Figure 15B, the deformation starting point position S1 in the magnetic reduction sections 74B, 74C, 76B, and 76C that sandwich the central sections 72B and 72C can be any position. The deformation starting point position S1 is the position where the opening diameter of the magnetic reduction sections 74B, 74C, 76B, and 76C widens towards both ends.

[0128] Furthermore, in order to suppress the nonlinearity of the magnetic spring caused by the magnet 22 and the outer yoke, the magnetic reduction sections 74 and 76, which reduce the magnetic attractive force, may be configured as cylindrical bodies with the same diameter as the central section to reduce the magnetic attractive force.

[0129] In the outer yoke 70D shown in Figure 16A, in the cylindrical main body, notches 702 may be provided in the magnetic reduction portions 74D and 76D on both axial sides of the central portion 72D such that the opening area gradually widens as it moves away from the central portion.

[0130] Furthermore, in the outer yoke 70E shown in Figure 16B, rectangular notches (slits) 703 may be provided in the magnetic reduction sections 76E, 76E, or a configuration with multiple perforations 704 may be provided, as in the outer yoke 70F shown in Figure 17. In the outer yoke 70F, by providing perforations 704 or arc-shaped notches 705, the magnetic attractive force generated between the movable body 20 and the magnet 22 when the movable body 20 moves back and forth may be reduced toward both ends, thereby linearizing the change in the magnetic spring.

[0131] The outer yokes 70D to 70F can all be formed using cylindrical yokes. In addition, in the vibration actuator 1, the outer yoke may cover the entire flange portions 46 and 47 of the coil holding portion 40 to which the outer yoke 70 is attached. Furthermore, the outer yokes 70D to 70F have magnetic reduction portions 74D to 74F and 76D to 76F, which are formed such that the opening area gradually increases from the central portion 72D to 72F towards both ends (the opening area gradually increases).

[0132] The coil holding portion 40G shown in Figure 18A has the same configuration as the coil holding portion 40, and the flange portions 46 and 47 are covered by the outer yoke 70G. The outer yoke 70G has a notch 706 that engages with the terminal block portion 464 of the flange portion 46.

[0133] In the outer yoke 70G, in order to ensure a balance of the magnetic attractive force generated between it and the movable body (not shown), notches 706 are provided at equal intervals in the circumferential direction in the flange portion 74G, which is a magnetic reduction portion, as shown in Figure 18B. As a result, even when the movable body reciprocates within the outer yoke 70G in the axial direction of the outer yoke 70G, the balance between the left and right sides is not disrupted, and it can be moved linearly in a suitable manner. Note that notches 706 may also be provided in the magnetic reduction portion (flange portion) 76.

[0134] Furthermore, the outer yoke 70 shown in Figure 1 may be an outer yoke 70H that is divided into left and right halves relative to the coil holding portion 40H, as shown in Figure 19. By combining and fitting the divided parts 708 and 709 in a cylindrical shape around the outer circumference of the coil holding portion 40H, in addition to the effects described above, the ease of assembly can be improved.

[0135] (Other Embodiments) Figure 20 is an external perspective view of a vibration actuator according to another embodiment of the present invention, Figure 21 is a cross-sectional view taken along line B-B in Figure 20, and Figure 22 is an exploded perspective view of the main components of the vibration actuator according to another embodiment of the present invention. Figure 23 is an enlarged view of the Y portion of Figure 21, and Figure 24 is an enlarged view of the Z portion of Figure 21.

[0136] As shown in Figures 20 to 22, the vibration actuator 100 is constructed by housing the actuator body 10, which constitutes the main part of a columnar vibrating body, in a case 300.

[0137] Compared to the actuator body of the vibration actuator 1, the actuator body 10 differs in the mounting state of the outer yoke 70, that is, the configuration of the coil holding portion 400, but the other configurations are the same. Therefore, in the following, only the configurations of the vibration actuator 100 that differ from those of the vibration actuator 1 will be described, and the same configurations will be given the same names and reference numerals and their descriptions will be omitted.

[0138] The case 300 has a bottomed cylindrical case body 310 that houses the actuator body 10, and a lid portion 320 that closes the opening 35 at the top of the case body 310. The case 300 is made of the same material as the coil holding portion 400, for example, a resin such as polybutylene terephthalate (PBT).

[0139] The case body 310 is formed such that the lower part of the cylindrical body 312 is closed by the bottom surface portion 314. Inside the cylindrical body 312 of the case body 310, an internal stepped portion 316 is provided on the inner circumferential surface on the bottom surface side, which protrudes toward the center of the cylindrical body 312 and is a step on which the actuator body 10 is placed. The outer circumference 804 of the elastic support portion 82 of the actuator body 10 or the lower end of the flange portion 47 of the coil holding portion 400 is placed on the internal stepped portion 316. The internal stepped portion 316 positions the elastic support portion 82 at a distance from the bottom surface portion 314, thereby securing the range of motion of the elastic support portion 82, that is, the range of motion of the movable body 20.

[0140] A notch 36 is provided in a part of the upper section surrounding the opening 35 of the case body 310, and is continuous with the opening 35. The notch 36 engages with the engaging projection 37 of the lid 320, thereby joining the lid 320 to the case body 310 in a positioned state.

[0141] The upper edge of the cylindrical body 312 of the case body 310 is provided with an engaging edge 318 that is formed to bend toward the opening 35. The engaging edge 318 engages with the lid body 322, including the outer circumference of the lid 320.

[0142] The engaging edge 318 may be bent from a state in which it protrudes upward in a continuous manner with the cylindrical body 312 toward the lid portion 320 fitted inside the opening 35, thereby connecting the engaging edge 318 to the lid portion 320 by crimping the outer circumference of the lid portion body 322. Alternatively, the engaging edge 318 may be constructed separately from the cylindrical body 312 and formed by joining it to the cylindrical body 312 with the lid portion 320 positioned in the opening 35 by welding, bonding, fastening, etc.

[0143] The lid portion 320 closes the opening 35 of the case body 310 and restricts the movement of the movable body 20 inside the actuator body 10 beyond the range in which the elastic support portion 81 can be elastically deformed when it moves in the axial direction.

[0144] The lid portion 320 has a lid-shaped cylindrical lid body 322, and a top surface portion 326 that protrudes upward is formed in the center of the upper surface of the lid body 322, and an engaging projection 37 is provided protruding from the outer surface of the cylindrical outer circumference of the lid body 322.

[0145] The engaging projection 37 engages with the terminal block portion 464 when it engages with the notch 36 of the case body 310.

[0146] The lower end portion (lower end portion of the outer circumference) 323 of the lid body 322 has a notch 324 that engages with the engaging projection 48 inside the cylindrical body 312. By engaging the engaging projection 48 and the notch 324 with each other, the lid body 322 is positioned and abuts against the upper end portion of the actuator body 10 inside the case body 310.

[0147] The actuator body 10 includes a movable body 20 and a fixed body 30 which corresponds to a fixed body body and has coils 51, 52, an outer yoke 70, and a coil holding portion 400 arranged radially outward from the movable body 20.

[0148] The coil holding portion 400 shown in Figures 21 and 22 has a different shape for the mounting location of the outer yoke 70 compared to the coil holding portion 40.

[0149] The coil holder portion 400 is made of the same material as the coil holder portion 40 and, like the coil holder portion 40, has a cylindrical body portion 42. Flange portions 44, 46, and 47 are provided on the outer circumferential surface of the cylindrical body portion 42, extending radially outward at predetermined intervals in the axial direction.

[0150] The outer surface of the central flange portion 44 is positioned by the back surface of the central portion 72 of the outer yoke 70 contacting it, and the magnetic reduction portions 74 and 76 engage with the flange portions 46 and 47 at the upper and lower ends of the coil holding portion 400. As a result, the outer yoke 70 is fitted into the concave portion formed by the flange portions 44, 46, 47 and the outer surface of the cylindrical body portion 42.

[0151] The flange portions 46 and 47 are formed in a cylindrical shape on the outer circumference of the cylindrical main body portion 42, opening in a direction (up and down) that separates them axially from the central flange portion 44. At the opening ends of the flange portions 46 and 47, i.e., the upper and lower ends, the engaging projections 48 engage in the axial direction with the positioning recesses 809 of the elastic support portions 81 and 82, thereby fixing the elastic support portions 81 and 82.

[0152] In the flange portions 46 and 47, the outer surfaces of the cylindrical flange bodies 462 and 472 are provided with engaging notches 466 and 476 that extend circumferentially and are recessed radially inward. The engaging notches 466 and 476 are formed to correspond to the shapes of the upper and lower ends 70c and 70d of the outer yoke 70 so that they engage with the upper and lower ends 70c and 70d of the outer yoke 70, respectively. Together with the flange portion 44, the engaging notches 466 and 476 form a concave notch into which the outer yoke 70 fits so as to surround the coils 51 and 52.

[0153] Figure 23 is an enlarged view of the Y portion of Figure 21.

[0154] The magnetic reduction sections 74 and 76 are formed to bend and widen from the ends 742 and 762 connected to both ends of the central section 72 toward the upper and lower ends 70c and 70d.

[0155] In the outer yoke 70, the ends 742 and 762 (end 742 is shown in Figure 23), which are the bending start positions of the magnetic reduction sections 74 and 76, are located axially outward from each of the ends of the movable magnetic section when not in operation, similar to the vibration actuator 1.

[0156] As shown in Figure 23, the end portion 742 of the magnetic reduction portion 74 is positioned on one end (upper end) side of the movable body 20, relative to the end face (surface) 242 of the yoke 24a. On the other hand, the end portion 762 of the magnetic reduction portion 76 is positioned on the other end side of the movable body 20, relative to the end face (surface) of the yoke 24b. They are positioned similarly to the outer yoke 70 of the vibration actuator 1 and have similar functions. For example, the length L (see Figure 21) between the ends 742 and 762 of the magnetic reduction portions 74 and 76 is preferably greater than or equal to the axial length R of the magnetic portion of the movable body, and furthermore, L is preferably R × 1.0 to 1.2.

[0157] Figure 24 is an enlarged view of section Z in Figure 21. Figure 24 shows the attachment state of the upper end portion 70c of the outer yoke 70 to the engagement notch 466 of the flange portion 46.

[0158] Referring to the engagement notch 466 in Figure 24, the engagement notches 466 and 476 have a shape in which the outer circumferential surface of the flange portions 46 and 47 (flange bodies 462 and 472) is cut out to open in the outer radial direction.

[0159] The engaging notches 466 and 476 have a radially extending end face 4662 and a rear side surface 4664 that slopes downward from the rear side of the end face 4662 toward the coils 51 and 52. The rear side surface (only the rear side surface 4664 is shown in Figure 24) is formed as a tapered surface that slopes downward toward the axial center. The rear side surface 4664 corresponds to the slope of the magnetic reduction section 74.

[0160] The engaging notches 466 and 476 engage the magnetic reduction portions 74 and 76 of the outer yoke 70 with the flange bodies 462 and 472. As a result, the upper and lower ends 70c and 70d of the outer yoke 70 are positioned flush with the outer surfaces of the flange portions 46 and 47, and are positioned in the axial direction.

[0161] The positional relationship between the outer yoke 70 and the coils 51 and 52, and the positional relationship between the outer yoke 70 and the yoke 24a are the same as in the vibration actuator 1 of the embodiment. The magnetic reduction portions 74 and 76 (upper and lower ends 70c and 70d) of the outer yoke 70 can engage with the upper and lower end faces (end face 4662 in Figure 24) of the engagement notches 466 and 476, respectively. By engaging, the outer yoke 70 can be positioned in the axial and radial directions.

[0162] The outer yoke 70 can reduce the stress on the elastic support parts 81 and 82 when they are made into mechanical springs, thereby improving the durability of the elastic support parts 81 and 82.

[0163] Furthermore, in the vibration actuators 1 and 100 having an outer yoke 70, the configuration may include one or three or more coils.

[0164] (Another Embodiment) Figure 25 is a longitudinal cross-sectional view of the main components of a vibration actuator in another embodiment, and Figure 26 is an exploded perspective view of the movable body in Figure 25.

[0165] As shown in Figure 25, the vibration actuator 110 may have three coils 54, 55, and 56 arranged around the outer circumference of the cylindrical coil holder 410. In this case, the movable body 200 will have two magnets 22-1 and 22-2, as shown in Figures 25 and 26.

[0166] The vibration actuator 110 shown in Figure 25 has the same configuration and function as the vibration actuator 100, except that the number of coils, the number of magnets, the number of yokes, and the shape of the coil holder 410 containing the coils are different. Therefore, in the vibration actuator 110, the same names and reference numerals are used for components that are the same as those in the vibration actuator 100, and their explanation is omitted.

[0167] The coil holding section 410 differs from the coil holding section 400 in that it has three coil arrangement sections 404, 405, and 406.

[0168] The coil holder 410 is a cylindrical, non-magnetic material made of resin, and has a cylindrical body portion 42 that houses the movable body 200 inside. Flange portions 44, 45, 46, and 47 are provided on the outer circumferential surface of the cylindrical body portion 42, extending radially outward at predetermined intervals in the axial direction.

[0169] The coil holding portion 410 is formed in the shape of a coil bobbin that holds coils 54, 55, and 56, with a cylindrical body portion 42 and flange portions 44, 45, 46, and 47. The coil holding portion 410 has concave coil arrangement portions 404, 405, and 406 that are separated together with the flange portions 44, 45, 46, and 47 on the outer surface of the cylindrical body portion 42. Coils 54, 55, and 56 are arranged in the coil arrangement portions 404, 405, and 406, respectively, so as to surround the outer circumference of the cylindrical body portion 42 (the bottom surface of the concave coil arrangement portions 404, 405, and 406).

[0170] A gap Da is formed between the inner circumferential surface 42a of the cylindrical main body portion 42 and the outer circumferential surface 20a of the movable body 200. The inner circumferential surface 42a is also the inner circumferential surface of the fixed body 30. The inner circumferential surface 42a is a flat surface without irregularities in the axial direction (vibration direction), as described above.

[0171] The coil arrangement sections 404, 405, and 406 open radially outward from the outer peripheral surfaces 424, 425, and 426 of the cylindrical main body 42, and are formed along the outer circumference with the outer peripheral surfaces 424, 425, and 426 of the cylindrical main body 42 as the bottom surface.

[0172] The coils 54, 55, and 56, which are placed in the concave coil arrangement sections 404, 405, and 406, are arranged in a state where they are wound around the outer surfaces 424, 425, and 426.

[0173] Furthermore, each of the coils 54, 55, and 56 is positioned in the axial center, facing each of the yokes 24a, 24b, and 24c of the movable body 200.

[0174] In the axially separated regions formed by coils 54, 55, and 56, the magnetic force generating parts (magnets 22-1, 22-2 and yokes 24a, 24b, and 24c) that constitute the magnetic circuit are arranged as movable magnetic parts.

[0175] Of the flange portions 44, 45, 46, and 47, the two central flange portions 44 and 45 are configured to have a smaller outer diameter than the outer circumference of flange portions 46 and 47. The outer circumferential surfaces of flange portions 44 and 45 are positioned set back inward from the outer end faces of flange portions 46 and 47. The outer circumferential surfaces of flange portions 44 and 45 abut against the back surface of the outer yoke 720, thereby positioning the outer yoke 720 radially. Notches 441 and 451 are formed in flange portions 44 and 45, where coil wires connecting coils 54, 55, and 56 are positioned.

[0176] The flange portions 46 and 47 are provided with engaging notches 4660 and 4760 that are cut radially outward. The magnetic reduction portions 74 and 76 of the outer yoke 720 (specifically, the upper and lower ends 70c and 70d) are fitted into the engaging notches 4660 and 4760.

[0177] As a result, when the outer yoke 720 is attached to the coil holding portion 410 so as to surround the coils 54, 55, and 56, its upper and lower ends 70c and 70d are positioned flush with the outer surface of the coil holding portion 410 without any step difference being formed.

[0178] Furthermore, by engaging the upper and lower ends 70c and 70d with the engaging notches 4660 and 4760, the outer yoke 720 is mounted to the coil holding portion 410 in an axially positioned state.

[0179] In the outer yoke 720, the magnetic reduction sections 74 and 76 are provided such that their diameters widen from both axial ends of the cylindrical central section 72. In the axial direction, the magnetic reduction sections 74 and 76 are located axially outward from each of the ends of the magnetic circuit (movable magnetic section) of the movable body 200 when it is not in motion. That is, the ends 742 and 762 of the magnetic reduction sections 74 and 76 that connect to the central section 72 are located axially towards the upper and lower ends of the movable body 200, respectively, than the end faces (surfaces) 242 and 244 of the yokes 24a and 24b.

[0180] The length between the ends 742 and 762 of the magnetic reduction sections 74 and 76 is greater than or equal to the axial length R of the magnetic section (magnetic force generating section) in the movable body 200, and furthermore, L is preferably R × 1.0 to 1.2. The outer yoke 720 can reduce the magnetic attractive force generated between it and the magnets 22-1 and 22-2 according to the position of the movable body 200 in the direction of vibration, so as to linearize the change in magnetic attractive force during reciprocating vibration.

[0181] The outer yoke 720 is positioned to cover the outer circumferential surfaces of the flange portions 44, 45, 46, and 47 and the coils 54, 55, and 56 from the radially outward direction. The flange portions 44, 45, 46, and 47 hold the outer yoke 720 with their outer circumferential surfaces.

[0182] Furthermore, the flange body 462 of the flange portion 46 is provided with a guide notch 467 that guides the winding wire so that it can be engaged with the terminal block portion 464 on which the terminal portion 5 is located.

[0183] In the movable body 200, two disc-shaped magnets 22-1 and 22-2 are arranged so that the same magnetic poles face each other, in order to correspond to three coils 54, 55, and 56 which are multiple coils. The magnets 22-1 and 22-2 are joined to the yoke 24c, for example, with the north poles of their respective back surfaces 22b and front surfaces 22c facing each other.

[0184] These magnets 22-1, 22-2, and yoke 24c are sandwiched between yokes 24a and 24b, with shaft 28 inserted through them.

[0185] Both ends of the shaft 28 are fitted into the connecting sleeves 26a and 26b, respectively. In other words, the movable body 200 is constructed by sandwiching and fixing the yoke 24a, magnet 22-1, yoke 24c, magnet 22-2, and yoke 24b between the connecting sleeves 26a and 26b, through which the shaft 28 is inserted.

[0186] The magnetic circuit of the movable body 200 has magnets 22-1 and 22-2 stacked on the front and back surfaces of the central yoke 24c, a yoke 24a stacked on the surface 22a of magnet 22-1, and a yoke 24b stacked on the back surface 22d of magnet 22-2. Similar to the movable body 20, joining sleeves 26a and 26b are stacked on the axially outer surfaces of the yokes 24a and 24b and joined to the inner circumference 802 of the elastic support parts 81 and 82.

[0187] In the vibration actuator 110, the magnets 22-1 and 22-2 are positioned facing each other, for example, with their north poles on their respective back surfaces 22b and front surfaces 22c sandwiching the yoke 24c.

[0188] In this configuration, when not driven, the magnetic flux emitted from the back surfaces 22b and front surfaces 22c of the pair of magnets 22-1 and 22-2 passes through the central yoke 24c and radiates toward the coil 54 in a radial direction perpendicular to the axial direction. The magnetic flux radiated from the outer edge of the central yoke 24c toward the coil 54 reaches the central part 72 of the outer yoke 720, passes through the central part 72 and the magnetic reduction parts 74 and 76, and enters the upper and lower yokes 24a and 24b via the upper and lower coils 55 and 56. From the upper and lower yokes 24a and 24b, it enters the magnets 22-1 and 22-2.

[0189] In this configuration, the central coil 54 and the upper and lower coils 55 and 56 are energized in different directions. For example, they are designed to generate magnetic fields in different directions.

[0190] The interaction between the magnetic fields of magnets 22-1 and 22-2 and the currents flowing through coils 54, 55, and 56 generates a force opposite to the Lorentz force in coils 54, 55, and 56, which acts as a thrust on the movable body 200 having magnets 22-1 and 22-2, causing the movable body 200 to move. The vibration actuator 110 can reverse the direction of current flow in coils 54, 55, and 56 using an AC power supply or the like, causing the movable body 200 to move in the reverse direction and outputting a more powerful and expressive vibration than that produced by two coils.

[0191] <Electronic Devices> Figures 27 and 28 show examples of mounting configurations for the vibration actuator 1. Figure 27 shows an example of the vibration actuator 1 being mounted on a game controller GC, and Figure 28 shows an example of the vibration actuator 1 being mounted on a mobile terminal M.

[0192] 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 27, 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.

[0193] 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.

[0194] 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).

[0195] As shown in Figures 27 and 28, 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.

[0196] 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, are parallel. The main surface of the terminal is the surface that contacts the user's body surface, and in this embodiment, it means the vibration transmission surface that contacts the user's body surface and transmits vibrations. Alternatively, the main surface of the terminal and the bottom surfaces of the bottoms of the vibration actuators 204, 205, and 206 may be arranged perpendicular to each other.

[0197] 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.

[0198] 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.

[0199] 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).

[0200] 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.

[0201] 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 20 vibrates in a direction perpendicular to the main surface of the game controller GC and the mobile terminal M.

[0202] 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.

[0203] Although the present invention has been specifically described above based on embodiments, the present invention is not limited to the above embodiments and can be modified without departing from its spirit.

[0204] Furthermore, the vibration actuator according to the present invention may be implemented in the user contact area of ​​portable devices other than the game controller GC and the mobile terminal M (for example, portable information terminals such as tablet PCs, portable game terminals, etc.). That is, the vibration actuator 1 may be implemented in the user contact area of ​​handheld electrical devices such as mobile terminals and electric beauty and grooming devices such as facial massagers. The vibration actuator 1 may also be implemented in the user contact area of ​​a wearable terminal that is worn and used by the user. In the case of handheld electrical devices such as the game controller GC, the user contact area is, for example, the handle that the user grips when using it. In the case of wearable electrical devices such as facial massagers, the user contact area is, for example, the pressure area that applies pressure to the user's body surface.

[0205] The disclosures in the specifications, drawings, and abstracts contained in Japanese applications No. 2025-015510 filed on January 31, 2025, and No. 2025-156206 filed on September 19, 2025, respectively, are incorporated herein by reference.

[0206] The vibration actuator according to the present invention can be miniaturized and is useful for mounting in electronic devices such as game consoles, exciters as vibration devices that produce sound, or mobile terminals, as it generates suitable vibrations with a wide bandwidth and low resonant frequency.

[0207] 1, 100, 110 Vibration actuator, 2 Fixed body, 3, 320 Cover, 4a, 6a, 316 Internal stepped section, 5 Terminal section, 6 Bracket, 10 Actuator body, 20, 200 Movable body, 20a Outer surface, 22, 22-1, 22-2 Magnet, 22a, 22c Front surface, 22b, 22d Back surface, 24a, 24b, 24c Yoke, 26a, 26b Joint sleeve (joint section), 28 Shaft, 32, 36, 702, 703, 705, 706 Notch, 35 Opening, 37 Engaging projection, 40, 40G, 40H, 400, 410 Coil holding section, 42 Cylindrical body section, 44, 45, 46, 47 Flange section, 46a, 47a Outer surface, 51, 52, 54, 55, 56 Coil, 70, 70A, 70B, 70C, 70D, 70E, 70F, 70G, 70H, 720 Outer yoke (yoke), 70c Upper end, 70d Lower end, 72, 72A, 72B, 72C, 72D, 72E, 72F Center, 74, 74A, 74B, 74C, 74D, 74E, 74F, 76, 76A, 76B, 76C, 76D, 76E, 76F, 76G Magnetic reduction section, 74G Flange section (magnetic reduction section), 81, 82 Elastic support section, 201 Communication section, 202 Processing section, 203 Drive control section, 242, 244 End face, 262 Joint body, 264 Sloping part, 266 Spring joint part, 268 Groove part, 300 Case, 310 Case body, 312 Cylindrical body, 314 Bottom surface part, 322 Lid body, 323 Lower end, 324 Notch, 401, 402, 404, 405, 406 Coil arrangement part, 421, 422, 424, 425, 426 Outer surface, 461, 471 Open end, 462, 472 Flange body, 464 Terminal block part, 466 Engaging notch, 467 Guide notch, 468 Guide groove, 469 Notched engaging part, 704 Perforated part, 708, 709 Divided body, 742, 762 End, 4662 End face, 4664 Back side

Claims

1. A vibration actuator comprising: a movable body having a disc-shaped magnet in the center and joints on the front and back sides of the magnet in the axial direction; a cylindrical fixed body housing the movable body, the fixed body having a coil positioned radially outward of the movable body and a cylindrical yoke surrounding the coil; and a pair of elastic support parts that support the movable body so as to be able to reciprocate in a vibration direction along the axial direction, with the outer circumference joined to the fixed body and the inner circumference joined to the joints, wherein the yoke has a shape that reduces the magnetic attractive force generated between it and the magnet according to the position of the movable body in the vibration direction, so as to linearize the change in magnetic attractive force during reciprocating vibration.

2. The vibration actuator according to claim 1, wherein the yoke has a central portion interposed between the coil and the outer circumference of the magnet, and magnetic reduction portions arranged on both sides of the central portion in the axial direction, which generate a magnetic attractive force that is reduced compared to the magnetic attractive force generated between the central portion and the magnet at the position opposite it when the magnets face each other radially outward.

3. The vibration actuator according to claim 2, wherein the magnetic reduction portion has a shape in which the opening diameters at both ends, which are spaced further apart in the axial direction, are wider than the opening diameter of the central portion.

4. The vibration actuator according to claim 3, wherein the magnetic reduction portion includes a plurality of notches spaced equally apart in the circumferential direction from the central portion to both ends.

5. The vibration actuator according to claim 4, wherein the magnetic reduction portion is formed such that the opening area gradually increases from the central portion towards both ends by the plurality of notches.

6. The vibration actuator according to claim 5, wherein the magnetic reduction portion has a plurality of perforations spaced equally apart in the circumferential direction from the end on the central side to the end on the side away from the central side.

7. The vibration actuator according to claim 6, wherein the magnetic reduction portion is formed such that the opening area increases from the central portion towards both ends by the plurality of perforations.

8. The vibration actuator according to claim 2, wherein the pair of magnetic reduction units are each located axially outward from the axial ends of the magnetic force generating unit including the magnet.

9. The vibration actuator according to claim 8, wherein, in the axial direction, the length between the central ends of each of the pair of magnetic reduction sections is 1.0 to 1.2 times the length between the two ends of the magnetic force generating section.

10. The vibration actuator according to claim 1, wherein the fixed body has a cylindrical coil holding portion that houses the movable body inside and on which the coil is arranged on its outer surface, and the coil holding portion has notches into which both ends of the yoke that covers the coil radially outward fit.

11. The vibration actuator according to claim 1, wherein the fixed body is a cylindrical body having a coil holding portion that houses the movable body inside and holds the coil which is arranged radially outward, the outer circumference of the coil holding portion is provided with a recessed notch into which the yoke fits so as to surround the coil, and a flange portion is provided in the notch that is arranged to protrude radially outward and abuts against the central part of the yoke.

12. The vibration actuator according to claim 1, comprising a plurality of magnets and a plurality of coils corresponding to the plurality of magnets, wherein the plurality of magnets are arranged with the same magnetic poles facing each other.

13. An electrical device comprising the vibration actuator described in claim 1.

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