Vibration actuator

Abstract

To provide a vibration actuator capable of increasing vibration torque.SOLUTION: A vibration actuator 10 has a first plate 21 and a second plate 31 facing the first plate. The first plate includes a magnet attachment surface 50 to which a magnet rear surface 22a is attached, and a coil facing surface 53 facing a coil surface 33b. The second plate includes a coil attachment surface 60 to which a coil rear surface 33a is attached, and a magnet facing surface 62 facing a magnet surface 22b. An interval between the coil attachment surface and the coil facing surface is narrower than an interval between the magnet attachment surface and the magnet facing surface.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to vibration actuators. [Background technology]

[0002] Devices such as smartphones, tablets, and game controllers are equipped with a feedback function that provides users with a tactile sensation through vibration. To achieve this feedback function, a linear vibration actuator has been proposed that vibrates a mover using electromagnetic force (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2019 / 151232 Summary of the Invention [Problem to be solved by the invention]

[0004] However, as devices such as smartphones are required to be thinner, vibration actuators such as linear vibration actuators are also required to be thinner. However, because thinner vibration actuators cause a decrease in vibration torque, there is a demand to increase the vibration torque of vibration actuators. [Means for solving the problem]

[0005] According to the present disclosure, a vibration actuator includes a first plate and a second plate facing the first plate. The vibration actuator includes a plate-shaped magnet having a magnet back surface attached to the first plate and a magnet front surface located opposite the magnet back surface and facing the second plate. The vibration actuator includes a plate-shaped coil having a coil back surface attached to the second plate and a coil front surface located opposite the coil back surface and facing the first plate. The vibration actuator includes an elastic member having a first end attached to the first plate and a second end attached to the second plate. The first plate includes a magnet mounting surface to which the magnet back surface is attached and a coil facing surface facing the coil front surface. The second plate includes a coil mounting surface to which the coil back surface is attached and a magnet facing surface facing the magnet front surface. The gap between the coil mounting surface and the coil facing surface is narrower than the gap between the magnet mounting surface and the magnet facing surface. [Effects of the Invention]

[0006] According to the present disclosure, the vibration torque of the vibration actuator can be increased. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view showing a smartphone equipped with a vibration actuator according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a perspective view showing the vibration actuator. [Figure 3] FIG. 3 is an exploded perspective view showing the internal structure of the vibration actuator. [Figure 4] FIG. 4 is a cross-sectional view showing the vibration actuator taken along line AA in FIG. [Figure 5] FIG. 5 is a cross-sectional view showing the disassembled state of the vibration actuator shown in FIG. [Figure 6] FIG. 6 is a perspective view showing the vibration actuator with the movable plate removed. [Figure 7] FIG. 7 is a diagram showing the positional relationship between the slits formed in the movable plate and the fixed plate, and the plate magnets and plate coils. [Figure 8] FIG. 8 is a diagram showing the operating state of the vibration actuator. [Figure 9] FIG. 9 is a diagram showing an operating state of the vibration actuator. [Figure 10] FIG. 10 is a cross-sectional view showing a vibration actuator of the first modification. [Figure 11] FIG. 11 is a cross-sectional view showing a vibration actuator according to the second modification. [Figure 12] FIG. 12 is an exploded perspective view showing a part of the vibration actuator of the third modification. [Figure 13] FIG. 13 is a cross-sectional view showing a vibration actuator according to the third modification. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description, identical or substantially identical configurations and elements will be designated by the same reference numerals and repeated description will be omitted.

[0009] <Electronic device equipped with vibration actuator> Fig. 1 is a perspective view showing a smartphone 11 equipped with a vibration actuator 10 according to an embodiment of the present disclosure. As shown in Fig. 1, the vibration actuator 10 is attached to a display 12 and other components of the smartphone 11, which is an electronic device. By using this vibration actuator 10 to control the vibration pattern of the display 12, a user who touches the display 12 can be given a tactile sensation such as a clicking sensation due to vibration.

[0010] In the illustrated example, the vibration actuator 10 is attached to the display 12, but this is not limiting and the vibration actuator 10 may also be attached to the housing 13 of the smartphone 11. In this case, the vibration pattern of the housing 13 can be controlled using the vibration actuator 10, and a tactile sensation can be given to a user touching the housing 13 through vibration. These vibration feedback technologies are also called haptics technologies. The vibration actuator 10 is also called a linear vibration actuator, a linear vibration motor, or the like.

[0011] An electronic control unit (not shown) including a microcontroller, a drive circuit, and the like is connected to the vibration actuator 10. By using this electronic control unit to control the current flowing through a plate-shaped coil (described later), the vibration actuator 10 can be made to vibrate in a predetermined vibration pattern. In the example shown, the vibration actuator 10 is incorporated into a smartphone 11, but this is not a limitation and the vibration actuator 10 may also be incorporated into other devices. For example, the vibration actuator 10 may be incorporated into a mobile device such as a tablet, an in-vehicle display installed in a vehicle, or an operating device such as a game controller or joystick.

[0012] <Vibration Actuator Structure> Fig. 2 is a perspective view showing vibration actuator 10, and Fig. 3 is an exploded perspective view showing the internal structure of vibration actuator 10. Fig. 4 is a cross-sectional view showing vibration actuator 10 taken along line AA in Fig. 2, and Fig. 5 is a cross-sectional view showing the exploded state of vibration actuator 10 shown in Fig. 4. Furthermore, Fig. 6 is a perspective view showing vibration actuator 10 with movable plate 21 removed.

[0013] 2 and 3, vibration actuator 10 has a mover unit 20 including plate-shaped magnets 22, 23, and 24, and a stator unit 30 including plate-shaped coils 33 and 34. As shown in FIGS. 3 and 5, mover unit 20 has a movable plate (first plate) 21 made of a ferromagnetic material, three plate-shaped magnets 22, 23, and 24 attached to movable plate 21, and a frame-shaped weight 25 attached to movable plate 21. Stator unit 30 also has a fixed plate (second plate) 31 made of a ferromagnetic material, a flexible printed circuit board 32 attached to fixed plate 31, and two plate-shaped coils 33 and 34 attached to fixed plate 31 and flexible printed circuit board 32. As shown in FIGS. 3, 4, and 5, movable plate 21 and fixed plate 31 face each other.

[0014] The ferromagnetic material that forms the movable plate 21 and the fixed plate 31 can be, for example, ferritic stainless steel such as SUS430 or martensitic stainless steel such as SUS410. The ferromagnetic material is not limited to ferritic stainless steel or martensitic stainless steel, and the movable plate 21 and the fixed plate 31 may also be made using iron, nickel, or the like. The plate-shaped magnets 22, 23, 24 and the weight 25 are attached to the movable plate 21 by adhesive or the like, and the plate-shaped coils 33, 34 and the flexible printed circuit board 32 are attached to the fixed plate 31 by adhesive or the like.

[0015] 5, plate-shaped magnets 22, 23, and 24 serving as permanent magnets provided in mover unit 20 have magnet back surfaces 22a, 23a, and 24a attached to movable plate 21, and magnet front surfaces 22b, 23b, and 24b located on the opposite side of magnet back surfaces 22a, 23a, and 24a and facing fixed plate 31. Furthermore, width W1 of plate-shaped magnet 23 located in the center is set larger than width W2 of plate-shaped magnets 22 and 24 located at both ends. In other words, the magnetic force of plate-shaped magnet 23 located in the center is stronger than the magnetic force of plate-shaped magnets 22 and 24 located at both ends.

[0016] The plate coils 33, 34 provided in the stator unit 30 have coil back surfaces 33a, 34a attached to the fixed plate 31 and coil front surfaces 33b, 34b located opposite the coil back surfaces 33a, 34a and facing the movable plate 21. As shown in Fig. 3, the plate coil 33 has a pair of straight portions 40, 41 that are parallel to each other and a pair of bent portions 42a, 42b that connect the straight portions 40, 41. The plate coil 34 has a pair of straight portions 44, 45 that are parallel to each other and a pair of bent portions 46a, 46b that connect the straight portions 44, 45. The plate coils 33, 34 are air-core coils formed by winding electric wire, and air-core portions 43, 47 that are elongated hole-shaped spaces are provided in the centers of the plate coils 33, 34. That is, the plate coil 33 has an air-core portion 43 defined by a pair of straight portions 40 and 41 , and the plate coil 34 has an air-core portion 47 defined by a pair of straight portions 44 and 45 .

[0017] As shown in Fig. 5, the movable plate 21 has magnet mounting surfaces 50, 51, and 52 to which the magnet back surfaces 22a, 23a, and 24a are attached, and coil-facing surfaces 53 and 54 that face the coil front surfaces 33b and 34b. Similarly, the fixed plate 31 has coil mounting surfaces 60 and 61 to which the coil back surfaces 33a and 34a are attached, and magnet-facing surfaces 62, 63, and 64 that face the magnet front surfaces 22b, 23b, and 24b. The movable plate 21 and the fixed plate 31 are pressed parts formed by press working. The movable plate 21 has a plate main body portion 55 that has the magnet mounting surfaces 50, 51, and 52, and pressed portions 56 and 57 that are provided on the plate main body portion 55 and have the coil-facing surfaces 53 and 54. Similarly, the fixed plate 31 has a plate body portion 65 having magnet-facing surfaces 62, 63, 64, and pressed portions 66, 67 provided on the plate body portion 65 and having coil mounting surfaces 60, 61.

[0018] 4, the coil facing surfaces 53 and 54 of the movable plate 21 protrude toward the fixed plate 31 further than the magnet mounting surfaces 50, 51, and 52 of the movable plate 21. Furthermore, the coil mounting surfaces 60 and 61 of the fixed plate 31 protrude toward the movable plate 21 further than the magnet facing surfaces 62, 63, and 64 of the fixed plate 31. Here, the distance between the coil mounting surface 60 and the coil facing surface 53 is "G1", and the distance between the coil mounting surface 61 and the coil facing surface 54 is also "G1". Furthermore, the distance between the magnet mounting surface 50 and the magnet facing surface 62 is "G2", the distance between the magnet mounting surface 51 and the magnet facing surface 63 is "G2", and the distance between the magnet mounting surface 52 and the magnet facing surface 64 is "G2". The gap G1 between the coil mounting surfaces 60, 61 and the coil facing surfaces 53, 54 is set to be narrower than the gap G2 between the magnet mounting surfaces 50, 51, 52 and the magnet facing surfaces 62, 63, 64.

[0019] 3 and 5, the vibration actuator 10 has four rubber dampers (elastic members) 48 that connect the movable plate 21 and the fixed plate 31. Each rubber damper 48 has a first end 48a that is attached to the movable plate 21 by adhesive or the like, and a second end 48b that is attached to the fixed plate 31 by adhesive or the like. In this way, the movable plate 21 and the fixed plate 31 are connected via the rubber dampers 48, so that the movable plate 21 can be displaced relative to the fixed plate 31 by a stroke that corresponds to the amount of elastic deformation of the rubber dampers 48.

[0020] 4 and 5, the plate-shaped magnets 22, 23, 24 and the plate-shaped coils 33, 34 are arranged so that the magnet surfaces 22b, 23b, 24b and the coil surfaces 33b, 34b do not face each other in the thickness direction D1 of the vibration actuator 10. That is, as shown in Figures 4 and 6, the plate-shaped coil 33 is housed in the space between the plate-shaped magnet 22 and the plate-shaped magnet 23, and the plate-shaped coil 34 is housed in the space between the plate-shaped magnet 23 and the plate-shaped magnet 24. That is, the magnet surfaces 22b, 23b, 24b of the plate-shaped magnets 22, 23, 24 are located closer to the coil back surfaces 33a, 34a than the coil surfaces 33b, 34b of the plate-shaped coils 33, 34. In other words, the coil surfaces 33b, 34b of the plate-shaped coils 33, 34 are located closer to the magnet back surfaces 22a, 23a, 24a than the magnet surfaces 22b, 23b, 24b of the plate-shaped magnets 22, 23, 24. Also, the magnet surfaces 22b, 23b, 24b of the plate-shaped magnets 22, 23, 24 are located closer to the fixed plate 31 than the coil surfaces 33b, 34b of the plate-shaped coils 33, 34. In other words, the coil surfaces 33b, 34b of the plate-shaped coils 33, 34 are located closer to the movable plate 21 than the magnet surfaces 22b, 23b, 24b of the plate-shaped magnets 22, 23, 24.

[0021] As described above, by arranging the plate-shaped magnets 22, 23, 24 and the plate-shaped coils 33, 34 in parallel in the thickness direction D1 of the vibration actuator 10, it is possible to reduce the thickness of the vibration actuator 10, thereby achieving a thinner vibration actuator 10. This in turn makes it possible to achieve smaller and thinner devices in which the vibration actuator 10 is incorporated. The thickness direction D1 of the vibration actuator 10 is the direction perpendicular to the surfaces of the movable plate 21 and the fixed plate 31.

[0022] As shown in Figures 4 and 6, plate-shaped magnet 22 is disposed adjacent to straight portion 40 of plate-shaped coil 33, and plate-shaped magnet 23 is disposed adjacent to straight portion 41 of plate-shaped coil 33. Similarly, plate-shaped magnet 23 is disposed adjacent to straight portion 44 of plate-shaped coil 34, and plate-shaped magnet 24 is disposed adjacent to straight portion 45 of plate-shaped coil 34. Furthermore, side surface 22c of plate-shaped magnet 22 and side surface 40a of straight portion 40 face each other, and side surface 23c of plate-shaped magnet 23 and side surface 41a of straight portion 41 face each other. Similarly, side surface 23d of plate-shaped magnet 23 and side surface 44a of straight portion 44 face each other, and side surface 24c of plate-shaped magnet 24 and side surface 45a of straight portion 45 face each other.

[0023] 7 is a diagram showing the positional relationship between the slits 70, 71, 72, and 73 formed in the movable plate 21 and the fixed plate 31 and the plate magnets 22, 23, and 24 and the plate coils 33, 34. As shown in FIGS. 3 and 7, the movable plate 21 and the fixed plate 31 have coil-side slits (openings) 70 and 71 that open to the air-core portions 43 and 47 of the plate coils 33, 34. The coil-side slits 70 and 71 not only open toward the air-core portions 43 and 47 of the plate coils 33, 34, but also extend to overlap the bent portions 42a, 42b, 46a, and 46b of the plate coils 33, 34. The movable plate 21 and the fixed plate 31 also have magnet-side slits 72 and 73 that open near the plate magnets 22 and 24.

[0024] As shown in Fig. 5, the width dimension W3 of the coil-side slits 70, 71 and the width dimension W4 of the air-core portions 43, 47 are set to coincide with each other. In the example shown, the width dimensions W3, W4 are set to coincide with each other, but this is not limited thereto, and the width dimension W3 of the coil-side slits 70, 71 may be set to be larger than the width dimension W4 of the air-core portions 43, 47. In other words, it is desirable to set the width dimension W3 of the coil-side slits 70, 71 to be equal to or larger than the width dimension W4 of the air-core portions 43, 47. Note that the width direction D2 when defining the width dimensions W3, W4 is the direction perpendicular to the longitudinal direction D3 of the straight portion.

[0025] <Operation of the vibration actuator> 8 and 9 are diagrams showing the operating conditions of the vibration actuator 10. Also, Figs. 8 and 9 show the same parts as those shown in Fig. 4. To facilitate explanation of the operation of the vibration actuator 10, Figs. 8 and 9 show the vibration actuator 10 enlarged in the thickness direction. Also, Fig. 8 shows a state in which current is passed through the plate coils 33 and 34 in the direction of arrow A1 in Fig. 6, and Fig. 9 shows a state in which current is passed through the plate coils 33 and 34 in the direction of arrow A2 in Fig. 6.

[0026] 8, the plate-shaped magnets 22 and 24 located at both ends are magnetized so that the north pole appears on magnet surfaces 22b and 24b, and the plate-shaped magnet 23 located in the center is magnetized so that the south pole appears on magnet surface 23b. In this way, the plate-shaped magnets 22 and 24 located at both ends and the plate-shaped magnet 23 located in the center are magnetized with polarities opposite to each other.

[0027] By magnetizing the plate-shaped magnets 22, 23, and 24 in this manner, a magnetic field H1 directed from the fixed plate 31 to the movable plate 21 is generated in the straight portion 40 of the plate-shaped coil 33, and a magnetic field H2 directed from the movable plate 21 to the fixed plate 31 is generated in the straight portion 41 of the plate-shaped coil 33. A magnetic field H3 directed from the movable plate 21 to the fixed plate 31 is generated in the straight portion 44 of the plate-shaped coil 34, and a magnetic field H4 directed from the fixed plate 31 to the movable plate 21 is generated in the straight portion 45 of the plate-shaped coil 34. The width W1 of the central plate-shaped magnet 23 is greater than the width W2 of the plate-shaped magnets 22 and 24 located at both ends. This increases the magnetic force of the plate-shaped magnet 23, allowing sufficient magnetic fields H2 and H3 to be generated in the two straight portions 41 and 44.

[0028] With magnetic fields H1 to H4 generated, when current flows through the straight portions 40, 41, 44, and 45 of the plate coils 33 and 34 as shown by arrows A1 in Fig. 6, a Lorentz force F1a is generated in the straight portion 40, and as a result of the reaction, a thrust F1b is generated in the plate magnet 22 in a direction toward the straight portion 40, as shown in Fig. 8. A Lorentz force F2a is generated in the straight portion 41, and as a result of the reaction, a thrust F2b is generated in the plate magnet 23 in a direction away from the straight portion 41. A Lorentz force F3a is generated in the straight portion 44, and as a result of the reaction, a thrust F3b is generated in the plate magnet 23 in a direction toward the straight portion 44. A Lorentz force F4a is generated in the straight portion 45, and as a result of the reaction, a thrust F4b is generated in the plate magnet 24 in a direction away from the straight portion 45. In this way, thrusts F1b, F2b, F3b, and F4b act on the mover unit 20, so that the mover unit 20 is displaced in the direction of arrow X1 while deforming the rubber damper .

[0029] On the other hand, when current flows through the straight portions 40, 41, 44, and 45 of the plate coils 33 and 34 as shown by arrow A2 in Fig. 6, a Lorentz force F1c is generated in the straight portion 40, and as a result of the reaction, a thrust F1d is generated in the plate magnet 22 in a direction away from the straight portion 40, as shown in Fig. 9. A Lorentz force F2c is generated in the straight portion 41, and as a result of the reaction, a thrust F2d is generated in the plate magnet 23 in a direction toward the straight portion 41. A Lorentz force F3c is generated in the straight portion 44, and as a result of the reaction, a thrust F3d is generated in the plate magnet 23 in a direction away from the straight portion 44. A Lorentz force F4c is generated in the straight portion 45, and as a result of the reaction, a thrust F4d is generated in the plate magnet 24 in a direction toward the straight portion 45. In this way, thrusts F1d, F2d, F3d, and F4d act on the mover unit 20, so that the mover unit 20 is displaced in the direction of arrow X2 while deforming the rubber damper .

[0030] That is, by switching the current flow direction of the plate coils 33, 34, the thrust acting on the mover unit 20 can be switched between the direction of arrow X1 and the direction of arrow X2. This allows the mover unit 20 to reciprocate at a predetermined stroke, causing the vibration actuator 10 to vibrate. By using this vibration actuator 10 to control the vibration pattern of the display 12, for example, it is possible to provide a tactile sensation such as a clicking sensation due to the vibration to a user touching the display 12.

[0031] <Strengthening of vibration torque 1> As shown in FIG. 4 , the distance G1 between the coil mounting surfaces 60, 61 and the coil facing surfaces 53, 54 is narrower than the distance G2 between the magnet mounting surfaces 50, 51, 52 and the magnet facing surfaces 62, 63, 64. This allows the movable plate 21 to be closer to the plate coils 33, 34, thereby narrowing the air gap between the coil surfaces 33b, 34b and the coil facing surfaces 53, 54. Furthermore, because magnetic flux has difficulty flowing in air, narrowing the air gap makes it easier for the magnetic flux to flow, thereby increasing the magnetic flux acting on the straight portions 40, 41, 44, 45 and increasing the vibration torque of the mover unit 20. In other words, to reduce the thickness of the vibration actuator 10, the plate magnets 22, 23, 24 and the plate coils 33, 34 are arranged in parallel in the thickness direction D1 of the vibration actuator 10. However, even with this structure, the vibration torque of the mover unit 20 can be sufficiently ensured.

[0032] As described above, the width W3 of the coil-side slits 70, 71 is set to be equal to or greater than the width W4 of the air-core portions 43, 47. This allows almost the entire coil-facing surfaces 53, 54 to face the coil surfaces 33b, 34b, thereby increasing the magnetic flux perpendicular to the coil surfaces 33b, 34b. In other words, the magnetic flux directed toward the air-core portions 43, 47 can be reduced, and the magnetic flux directed toward the straight portions 40, 41, 44, 45 can be increased. This increases the thrust acting on the plate-shaped magnets 22, 23, 24, and increases the vibration torque of the mover unit 20.

[0033] <Variation 1> In the example shown in Fig. 4, pressed portions 56, 57, 66, 67 are provided on both the movable plate 21 and the fixed plate 31, but this is not limited to this. For example, pressed portions 56, 57 may be provided only on the movable plate 21, or pressed portions 66, 67 may be provided only on the fixed plate 31. Fig. 10 is a cross-sectional view showing a vibration actuator 80 of Modified Example 1. Fig. 10 shows the same parts as those shown in Figs. 4 and 8.

[0034] 10, vibration actuator 80 has mover unit 81 including plate-shaped magnets 22, 23, and 24, and stator unit 30 including plate-shaped coils 33 and 34. Mover unit 81 has a flat movable plate (first plate) 82 made of a ferromagnetic material. Stator unit 30 also has a fixed plate (second plate) 31 made of a ferromagnetic material with pressed portions 66 and 67. In this way, even when pressed portions 66 and 67 are formed only on fixed plate 31, it is possible to make distance G3 between coil mounting surfaces 60 and 61 and coil facing surfaces 53 and 54 narrower than distance G2 between magnet mounting surfaces 50, 51, and 52 and magnet facing surfaces 62, 63, and 64.

[0035] This allows the movable plate 82 to be closer to the plate-shaped coils 33, 34, narrowing the air gap between the coil surfaces 33b, 34b and the coil-facing surfaces 53, 54. This in turn increases the magnetic flux acting on the straight portions 40, 41, 44, 45, thereby enhancing the vibration torque of the mover unit 81. While the pressed portions 66, 67 are provided only on the fixed plate 31 in the example shown in FIG. 10 , this is not a limitation, and the pressed portions 56, 57 may be provided only on the movable plate 21. Because the plate-shaped magnets 22, 23, 24 are not in contact with the fixed plate 31, it is desirable to provide the pressed portions 66, 67 on the fixed plate 31 in order to efficiently improve the magnetic circuit.

[0036] <Variation 2> In the example shown in Fig. 4, both the movable plate 21 and the fixed plate 31 are provided with pressed portions 56, 57, 66, 67, but this is not limited to this. For example, an auxiliary plate may be provided on the movable plate 21 instead of the pressed portions 56, 57, and an auxiliary plate may be provided on the fixed plate 31 instead of the pressed portions 66, 67. Fig. 11 is a cross-sectional view showing a vibration actuator 90 of Modified Example 2. Fig. 11 shows the same parts as those shown in Figs. 4 and 8.

[0037] 11, vibration actuator 90 includes mover unit 91 including plate-shaped magnets 22, 23, and 24, and stator unit 92 including plate-shaped coils 33 and 34. Mover unit 91 includes a movable plate (first plate) 93 made of a ferromagnetic material. This movable plate 93 includes a plate main body 94 including magnet mounting surfaces 50, 51, and 52, and auxiliary plates 95a and 95b attached to plate main body 94 and including coil-facing surfaces 53 and 54. Stator unit 92 also includes a fixed plate (second plate) 96 made of a ferromagnetic material. This fixed plate 96 includes a plate main body 97 including magnet-facing surfaces 62, 63, and 64, and auxiliary plates 98a and 98b attached to plate main body 97 and including coil mounting surfaces 60 and 61.

[0038] In this way, even when the movable plate 93 is configured using auxiliary plates 95a, 95b and the fixed plate 96 is configured using auxiliary plates 98a, 98b, the gap G4 between the coil mounting surfaces 60, 61 and the coil facing surfaces 53, 54 can be made narrower than the gap G2 between the magnet mounting surfaces 50, 51, 52 and the magnet facing surfaces 62, 63, 64. This allows the movable plate 93 to be closer to the plate coils 33, 34, and narrows the air gap between the coil surfaces 33b, 34b and the coil facing surfaces 53, 54. This in turn increases the magnetic flux acting on the straight portions 40, 41, 44, 45, and increases the vibration torque of the mover unit 91.

[0039] 11, auxiliary plates 95a, 95b, 98a, and 98b are attached to both the movable plate 93 and the fixed plate 96, but this is not limiting. That is, auxiliary plates 95a and 95b may be attached only to the movable plate 93, or auxiliary plates 98a and 98b may be attached only to the fixed plate 96. Note that, because the plate-shaped magnets 22, 23, and 24 are not in contact with the fixed plate 96, it is desirable to attach auxiliary plates 98a and 98b to the fixed plate 96 in order to efficiently improve the magnetic circuit.

[0040] <Strengthening vibration torque 2> As shown in Figures 3 and 7, the movable plate 21 and the fixed plate 31 are formed with coil-side slits 70, 71 and magnet-side slits 72, 73. By forming the slits 70, 71, 72, 73 in the movable plate 21 and the fixed plate 31 in this way, the magnetic circuit of the vibration actuator 10 can be improved. That is, as shown in Figure 7, the slits 70, 72 are arranged around the plate-shaped magnet 22 and the straight portion 40, which increases the magnetic flux from the plate-shaped magnet 22 toward the straight portion 40. Furthermore, the slits 70, 71 are arranged around the plate-shaped magnet 23 and the straight portions 41, 44, which increases the magnetic flux from the plate-shaped magnet 23 toward the straight portions 41, 44. Furthermore, the slits 71, 73 are arranged around the plate-shaped magnet 24 and the straight portion 45, which increases the magnetic flux from the plate-shaped magnet 24 toward the straight portion 45.

[0041] As described above, by forming the slits 70, 71, 72, and 73 in the movable plate 21 and the fixed plate 31, the magnetic circuit of the vibration actuator 10 can be improved. That is, because the magnetic resistance of the slits 70, 71, 72, and 73 in the movable plate 21 and the fixed plate 31 is higher than in other parts, it is possible to reduce the magnetic flux toward the slits 70, 71, 72, and 73 and increase the magnetic flux toward the straight portions 40, 41, 44, and 45. This increases the thrust acting on the plate-shaped magnets 22, 23, and 24, and increases the vibration torque of the mover unit 20. That is, from the perspective of making the vibration actuator 10 thinner, the plate-shaped magnets 22, 23, and 24 and the plate-shaped coils 33 and 34 are arranged in parallel in the thickness direction D1 of the vibration actuator 10, but even with this arrangement, the vibration torque of the mover unit 20 can be sufficiently ensured.

[0042] 3 and 7, the coil-side slits 70, 71 and the magnet-side slits 72, 73 are formed in the movable plate 21 and the fixed plate 31, but this is not limited to this. In other words, if the vibration torque of the mover unit 20 is sufficiently ensured, the magnet-side slits 72, 73 may be omitted from the movable plate 21, or the coil-side slits 70, 71 and the magnet-side slits 72, 73 may be omitted from the movable plate 21. Similarly, the magnet-side slits 72, 73 may be omitted from the fixed plate 31, or the coil-side slits 70, 71 and the magnet-side slits 72, 73 may be omitted from the fixed plate 31.

[0043] <Variation 3> In the example shown in Fig. 4, magnet surfaces 22b, 23b, and 24b of plate-shaped magnets 22, 23, and 24 are exposed, but this is not limitative, and pole pieces made of a ferromagnetic material may be attached to magnet surfaces 22b, 23b, and 24b. Fig. 12 is an exploded perspective view showing a portion of vibration actuator 100 of Modification 3. Fig. 13 is a cross-sectional view showing vibration actuator 100. Fig. 13 shows the same parts as those shown in Figs. 4 and 8.

[0044] 12, vibration actuator 100 has a mover unit 101 equipped with plate-shaped magnets 22, 23, and 24. Mover unit 101 has a movable plate 21 made of a ferromagnetic material, three plate-shaped magnets 22, 23, and 24 attached to movable plate 21, three pole pieces 102, 103, and 104 attached to plate-shaped magnets 22, 23, and 24, and a frame-shaped weight 25 attached to movable plate 21. Pole pieces 102, 103, and 104 are flat plates made of a ferromagnetic material such as ferritic stainless steel or martensitic stainless steel.

[0045] 13, by attaching pole pieces 102, 103, and 104 to plate-shaped magnets 22, 23, and 24, it is possible to generate a magnetic attractive force M1 in a direction inclined relative to magnet surfaces 22b, 23b, and 24b. This makes it possible to reduce the magnetic attractive force M2 in the vertical direction acting between magnet surfaces 22b, 23b, and 24b and fixed plate 31, thereby stabilizing the operation of vibration actuator 100. In other words, it is possible to avoid a situation in which plate-shaped magnets 22, 23, and 24 of movable plate 21 are held to fixed plate 31 by the magnetic attractive force M2 in the vertical direction, thereby stabilizing the operation of vibration actuator 100.

[0046] <Other variations> The present disclosure is not limited to the above-described embodiments and may be modified in various ways without departing from the spirit and scope of the present disclosure. In the example shown in FIG. 3, vibration actuator 10 is configured using three plate-shaped magnets 22, 23, and 24 and two plate-shaped coils 33 and 34. However, this is not limiting, and the number of plate-shaped magnets and plate-shaped coils constituting the vibration actuator may be changed. For example, a vibration actuator may be configured using one plate-shaped magnet and one plate-shaped coil. Furthermore, a vibration actuator may be configured using two plate-shaped magnets and one plate-shaped coil, or one plate-shaped magnet and two plate-shaped coils. Furthermore, a vibration actuator may be configured using four or more plate-shaped magnets, or three or more plate-shaped coils.

[0047] 3, plate-shaped magnets 22, 23, and 24 are attached to movable plate 21, and plate-shaped coils 33 and 34 are attached to fixed plate 31, but this is not limiting. For example, plate-shaped magnets 22, 23, and 24 may be attached to fixed plate 31, and plate-shaped coils 33 and 34 may be attached to movable plate 21. Furthermore, weight 25 is attached to movable plate 21, but this is not limiting. If movable plate 21 and plate-shaped magnets 22, 23, and 24 have sufficient mass, weight 25 may be removed from movable plate 21.

[0048] In the example shown in FIG. 3, rubber dampers 48 are used as elastic members connecting the movable plate 21 and the fixed plate 31, but this is not a limitation and springs may also be used as elastic members. Furthermore, in the example shown, four rubber dampers 48 are provided in the vibration actuator 10, but this is not a limitation and the number of rubber dampers 48 in the vibration actuator 10 may be set to three or fewer as long as the movable unit 20 can be appropriately supported. It goes without saying that five or more rubber dampers 48 may also be provided in the vibration actuator 10. Furthermore, in the example shown, the rubber dampers 48 are formed in a cylindrical shape, but this is not a limitation and the rubber dampers 48 may be formed in other shapes. For example, the rubber dampers 48 may be formed in a cylindrical shape, or the rubber dampers 48 may be formed in a rectangular column shape or a rectangular tube shape.

[0049] In the example shown in FIG. 8, the plate-shaped magnets 22 and 24 located at both ends are magnetized so that the north pole appears on the magnet surfaces 22b and 24b, and the plate-shaped magnet 23 located in the center is magnetized so that the south pole appears on the magnet surface 23b, but this is not limited to this. In other words, the plate-shaped magnets 22 and 24 located at both ends may be magnetized so that the south pole appears on the magnet surfaces 22b and 24b, and the plate-shaped magnet 23 located in the center may be magnetized so that the north pole appears on the magnet surface 23b. Also, in the example shown in FIG. 5, the width W1 of the plate-shaped magnet 23 located in the center is set larger than the width W2 of the plate-shaped magnets 22 and 24 located at both ends, but this is not limited to this. For example, the width W1 of the plate-shaped magnet 23 located in the center and the width W2 of the plate-shaped magnets 22 and 24 located at both ends may be made the same.

[0050] The present technology can be configured as follows. [1] A vibration actuator comprising a first plate and a second plate facing the first plate, a plate-shaped magnet having a magnet back surface attached to the first plate and a magnet front surface located opposite the magnet back surface and facing the second plate; a plate-shaped coil including a coil back surface attached to the second plate and a coil front surface positioned opposite the coil back surface and facing the first plate; a resilient member having a first end attached to the first plate and a second end attached to the second plate; and the first plate includes a magnet mounting surface to which the back surface of the magnet is attached and a coil facing surface facing the front surface of the coil, the second plate includes a coil mounting surface to which the back surface of the coil is attached and a magnet facing surface facing the front surface of the magnet, a gap between the coil mounting surface and the coil facing surface is narrower than a gap between the magnet mounting surface and the magnet facing surface; Vibration actuator. [2] In the vibration actuator according to the above [1], the coil-facing surface of the first plate is located closer to the second plate than the magnet mounting surface of the first plate; Vibration actuator. [3] In the vibration actuator according to the above [1] or [2], the coil mounting surface of the second plate is located closer to the first plate than the magnet-facing surface of the second plate; Vibration actuator. [4] In the vibration actuator according to any one of the above [1] to [3], The first plate has a plate main body portion having the magnet mounting surface, and a pressed portion provided on the plate main body portion and having the coil facing surface. Vibration actuator. [5] In the vibration actuator according to any one of the above [1] to [4], The second plate has a plate main body portion having the magnet facing surface, and a pressed portion provided on the plate main body portion and having the coil mounting surface. Vibration actuator. [6] In the vibration actuator according to any one of the above [1] to [5], The first plate has a plate body having the magnet mounting surface, and an auxiliary plate attached to the plate body and having the coil facing surface. Vibration actuator. [7] In the vibration actuator according to any one of the above [1] to [6], The second plate has a plate body having the magnet facing surface, and an auxiliary plate attached to the plate body and having the coil attachment surface. Vibration actuator. [8] In the vibration actuator according to any one of the above [1] to [7], The coil surface of the plate-shaped coil is located closer to the magnet back surface than the magnet surface of the plate-shaped magnet. Vibration actuator. [9] In the vibration actuator according to any one of the above [1] to [8], the first plate and the second plate are made of a ferromagnetic material and have openings that open into the hollow core of the plate-shaped coil. Vibration actuator.

[10] In the vibration actuator according to any one of the above [1] to [9], the plate-shaped coil has a pair of straight portions that define the air-core portion, When a direction perpendicular to the longitudinal direction of the straight portion is defined as a width direction, a width dimension of the opening is equal to or greater than a width dimension of the hollow core portion. Vibration actuator.

[11] In the vibration actuator according to any one of the above [1] to

[10] , The plate-shaped magnet is disposed adjacent to the straight portion of the plate-shaped coil. Vibration actuator.

[12] In the vibration actuator according to any one of the above [1] to

[11] , a weight attached to the first plate; Vibration actuator. [Explanation of symbols]

[0051] 10... vibration actuator, 21... movable plate (first plate), 22, 23, 24... plate-shaped magnet, 22a, 23a, 24a... back surface of magnet, 22b, 23b, 24b... front surface of magnet, 25... weight, 31... fixed plate (second plate), 33, 34... plate-shaped coil, 33a, 34a... back surface of coil, 33b, 34b... front surface of coil, 40, 41... straight portion, 43... hollow core portion, 44, 45... straight portion, 47... hollow core portion, 48... rubber damper (elastic member), 48a... first end, 48b... second end, 50, 51, 52... magnet mounting surface, 53, 54... coil facing surface, 55... plate body portion, 56, 57...pressed portion, 60, 61...coil mounting surface, 62, 63, 64...magnet facing surface, 65...plate main body portion, 66, 67...pressed portion, 70, 71...coil side slit (opening), 80...vibration actuator, 82...movable plate (first plate), 90...vibration actuator, 93...movable plate (first plate), 94...plate main body, 95a, 95b...auxiliary plate, 96...fixed plate (second plate), 97...plate main body, 98a, 98b...auxiliary plate, 100...vibration actuator, G1, G2, G3, G4...spacing, W3, W4...width dimension

Claims

1. A vibration actuator comprising a first plate and a second plate facing the first plate, a plate-shaped magnet having a magnet back surface attached to the first plate and a magnet front surface located opposite the magnet back surface and facing the second plate; a plate-shaped coil including a coil back surface attached to the second plate and a coil front surface positioned opposite the coil back surface and facing the first plate; a resilient member having a first end attached to the first plate and a second end attached to the second plate; and the first plate includes a magnet mounting surface to which the back surface of the magnet is attached and a coil facing surface facing the front surface of the coil, the second plate includes a coil mounting surface to which the back surface of the coil is attached and a magnet facing surface facing the front surface of the magnet, a gap between the coil mounting surface and the coil facing surface is narrower than a gap between the magnet mounting surface and the magnet facing surface; Vibration actuator.

2. 2. The vibration actuator according to claim 1, the coil-facing surface of the first plate is located closer to the second plate than the magnet mounting surface of the first plate; Vibration actuator.

3. 3. The vibration actuator according to claim 1, the coil mounting surface of the second plate is located closer to the first plate than the magnet-facing surface of the second plate; Vibration actuator.

4. 2. The vibration actuator according to claim 1, The first plate has a plate main body portion having the magnet mounting surface, and a pressed portion provided on the plate main body portion and having the coil facing surface. Vibration actuator.

5. 5. The vibration actuator according to claim 1, The second plate has a plate main body portion having the magnet facing surface, and a pressed portion provided on the plate main body portion and having the coil mounting surface. Vibration actuator.

6. 2. The vibration actuator according to claim 1, The first plate has a plate body having the magnet mounting surface, and an auxiliary plate attached to the plate body and having the coil facing surface. Vibration actuator.

7. 10. The vibration actuator according to claim 1, The second plate includes a plate body having the magnet facing surface, and an auxiliary plate attached to the plate body and having the coil attachment surface. Vibration actuator.

8. 2. The vibration actuator according to claim 1, The coil surface of the plate-shaped coil is located closer to the magnet back surface than the magnet surface of the plate-shaped magnet. Vibration actuator.

9. 2. The vibration actuator according to claim 1, the first plate and the second plate are made of a ferromagnetic material and have openings that open into the hollow core portion of the plate-shaped coil. Vibration actuator.

10. 10. The vibration actuator according to claim 9, the plate-shaped coil has a pair of straight portions that define the air-core portion, When a direction perpendicular to the longitudinal direction of the straight portion is defined as a width direction, a width dimension of the opening is equal to or greater than a width dimension of the hollow core portion. Vibration actuator.

11. 2. The vibration actuator according to claim 1, The plate-shaped magnet is disposed adjacent to the straight portion of the plate-shaped coil. Vibration actuator.

12. 2. The vibration actuator according to claim 1, a weight attached to the first plate; Vibration actuator.

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