Vibrator

Abstract

To provide a vibrator which achieves high levels of water tightness and heat radiation performance.SOLUTION: A vibrator 1 includes: a movable part 5 having a first permanent magnet 30, a yoke 10 for controlling flow of magnetic flux flowing out from the first permanent magnet 30, and a frame 40 for supporting the first permanent magnet 30 and the yoke 10; a coil part 50 which is energized in a direction that interlinks with the magnetic flux to apply propulsion power to the movable part 5; a base 70 which fixes the coil part 50; a damper part 60 which supports the movable part 5 so as to enable the movable part 5 to reciprocate relative to the coil part 50; and a cover 80 which is joined to the base 70 and houses the movable part 5, the coil part 50, and the damper part 60. The yoke 10 has a hole 15 extending in a direction along a direction in which the propulsion power acts. The cover 80 has a protruding part 84 fitted in the hole 15.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] Conventionally, a vibrator that transmits its own vibration to a vibrated object has been known. Patent Document 1 discloses a vibrator (referred to as an "electro-mechanical vibration converter" in Patent Document 1). The vibrator disclosed in Patent Document 1 includes a yoke, a magnet, and a plate (hereinafter collectively referred to as the "moving part") that form a magnetic circuit, a damper that supports the moving part so that it can swing, a voice coil that applies a driving force to the moving part, and a metal case and cover that house the moving part, the damper, and the voice coil. The vibrator disclosed in Patent Document 1 is covered with a vibrating body made of hard polyethylene foam and an elastic body made of sponge to form a cushion. The cushion with a built-in vibrator is used when playing and listening to music. When listening to music, the elastic side of the cushion is placed against the body, and vibrations corresponding to the low-frequency range of the music being played are generated from the vibrator. This allows the listener to experience the music through both the sound coming from the speaker and the vibrations generated by the vibrator, thereby enhancing the sense of realism when listening to music. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 55-124995 Summary of the Invention [Problem to be solved by the invention]

[0004] In the vibrator disclosed in Patent Document 1, a relatively large current flows through the voice coil, causing the voice coil to generate heat. This heat is transferred to the moving parts and stored there. As a result, the entire vibrator becomes very hot, which could damage the insulating layer and fusion layer of the copper wire used in the voice coil. Therefore, the vibrator in Patent Document 1 is configured with multiple ventilation holes in the case so that heat generated by the passage of current through the voice coil can be released to the outside through the ventilation holes.

[0005] However, providing a vent in the case raises the risk of dust or liquid entering the inside of the vibrator, which could adversely affect the operation of the vibrator, leaving room for improvement.

[0006] Therefore, there is a demand for a vibrator that is highly watertight and has good heat dissipation properties. [Means for solving the problem]

[0007] One embodiment of a vibrator according to the present disclosure includes a movable part having a first permanent magnet, a yoke that controls the flow of magnetic flux from the first permanent magnet, and a frame that supports the first permanent magnet and the yoke; a coil part that is energized in a direction that intersects with the magnetic flux and applies a propulsive force to the movable part; a base that fixes the coil part; a damper part that supports the movable part so that it can be propelled back and forth relative to the coil part; and a cover that is joined to the base and houses the movable part, the coil part, and the damper part inside, wherein the yoke has a hole that extends in a direction along the direction in which the propulsive force acts, and the cover has a protrusion that is fitted into the hole.

[0008] In the vibrator of this embodiment, the cover and base are joined together, and the internal space formed by the cover and base is watertight. This prevents dust or liquid from entering the internal space of the vibrator from the outside, eliminating the risk of these particles adversely affecting the operation of the vibrator. Meanwhile, the watertight internal space houses the moving part, coil part, and damper part, so heat generated by energizing the coil part remains in the internal space. As a result, the heat raises the temperature of the internal space, causing the entire vibrator, including the moving part and coil part, to become too hot, potentially damaging the insulating layer and fusion layer of the copper wire used in the coil part.

[0009] Therefore, in the vibrator of this embodiment, the yoke has a hole extending in the direction of the thrust force, and the cover has a protrusion that fits into the hole. Therefore, heat conducted to the yoke from the coil or the air in the internal space is conducted to the protrusion of the cover, then from the protrusion to the surface of the cover, and released from the surface of the cover to the outside of the vibrator. This prevents the insulation layer and fusion layer of the copper wire from being damaged, even if the entire vibrator becomes hot. In this way, a vibrator with high watertightness and good heat dissipation properties has been realized.

[0010] In another embodiment of the vibrator according to the present disclosure, it is preferable that the cover including the protrusion is made of metal.

[0011] According to this embodiment, since metal has a relatively high thermal conductivity, by making the cover including the protruding portion out of metal, heat can be more efficiently released to the outside of the vibrator.

[0012] In another embodiment of the vibrator according to the present disclosure, it is preferable that thermally conductive grease is disposed between the inner circumferential surface of the hole of the yoke and the protrusion.

[0013] According to this embodiment, since the thermal conductivity of the thermal conductive grease is higher than that of air, by placing the thermal conductive grease between the inner surface of the hole in the yoke and the protrusion, heat can be more efficiently released to the outside of the vibrator.

[0014] In one embodiment of the vibrator according to the present disclosure, it is preferable that a second permanent magnet is disposed on at least a portion of the protrusion, and that a magnetic fluid is disposed between the inner circumferential surface of the hole of the yoke and the second permanent magnet.

[0015] According to this embodiment, since magnetic fluid has a higher thermal conductivity than air, by disposing the magnetic fluid between the inner circumferential surface of the hole in the yoke and the second permanent magnet, heat can be more efficiently released to the outside of the vibrator. In addition, the magnetic fluid also functions as a sliding bearing, allowing the moving part to smoothly reciprocate.

[0016] In another embodiment of the vibrator according to the present disclosure, the coil section preferably has a bobbin fixed to the base and a coil wound around the bobbin, and the bobbin and the base are preferably made of metal.

[0017] According to this embodiment, the main heat generation in the coil section is due to the current applied to the coil, so by making the bobbin around which the coil is wound and the base to which the coil section is fixed out of a metal with high thermal conductivity, the heat generated in the coil can be conducted from the bobbin to the base and released from the surface of the base.

[0018] In another embodiment of the vibrator according to the present disclosure, it is preferable that a heat dissipation paint is applied to a surface of at least one of the cover and the base.

[0019] According to this embodiment, heat dissipation paint is applied to the surface of at least one of the cover and the base, so that heat can be dissipated to the outside of the vibrator more efficiently than when no heat dissipation paint is applied. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 2 is a front view of the vibrator according to the first embodiment. [Figure 2]FIG. [Figure 3] FIG. [Figure 4] FIG. [Figure 5] FIG. 10 is a vertical cross-sectional view of a vibrator according to a second embodiment. [Figure 6] FIG. 10 is a vertical cross-sectional view of a vibrator according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, embodiments of a vibration exciter according to the present disclosure will be described in detail with reference to the drawings. Note that the embodiments described below are examples for explaining the vibration exciter, and the vibration exciter is not limited to these embodiments. Therefore, the vibration exciter can be implemented in various forms without departing from the gist of the present disclosure. Note that the vibration exciter according to the present disclosure is used in massage chairs and car speakers, but can also be used for other purposes if possible.

[0022] [First embodiment] [Configuration of the vibrator] As shown in FIGS. 1 to 4, the vibrator 1 according to the first embodiment includes a first yoke 10 (an example of a yoke), a second yoke 20, a magnet 30 (an example of a first permanent magnet), a frame 40, a coil unit 50 (an example of a coil section), a damper 60 (an example of a damper section), a base 70, a cover 80, and a substrate 90. The vibrator 1 is configured by joining a cover 80 having a substantially cylindrical shape with a bottom to a substantially circular plate-shaped base 70, and accommodating the first yoke 10, the second yoke 20, the magnet 30, the frame 40, the coil unit 50, and the damper 60 in an internal space 81 (see FIG. 4). Hereinafter, the central axis of the cylindrical shape of the cover 80 will be referred to as the axis X. The base 70 has a substantially circular plate shape and is joined to the cover 80 so that its center is located on the axis X. In the following description, the direction parallel to the axis X will be referred to as the Z direction. The direction and side in which the cover 80 is disposed relative to the base 70 will be referred to as the Z1 direction and Z1 side, and the opposite direction and side will be referred to as the Z2 direction and Z2 side.

[0023] The first yoke 10 is made of a soft magnetic material such as low-carbon steel or silicon iron. The first yoke 10 controls the flow of magnetic flux emitted from the magnet 30. The first yoke 10 has a substantially disk-shaped disk portion 12 and a cylindrical portion 14 extending in the Z2 direction from the center of the disk portion 12. The outer diameter of the disk portion 12 is larger than the outer diameter of the cylindrical portion 14. The center of the disk portion 12 is located on the central axis of the cylindrical portion 14. The central axis of the cylindrical portion 14 is coaxial with the axis X. In addition, a through hole 15 (an example of a hole) with a circular cross section is formed from the disk portion 12 to the cylindrical portion 14. The central axis of the through hole 15 is coaxial with the central axis of the cylindrical portion 14. Furthermore, an annular positioning portion 16 protruding radially outward is formed on the outer peripheral surface of the cylindrical portion 14. The positioning portion 16 is formed at the boundary between the cylindrical portion 14 and the disk portion 12.

[0024] The magnet 30 is a permanent magnet such as a ferrite magnet. The magnet 30 has a cylindrical shape. The magnet 30 is disposed on the Z2 side of the disk portion 12 of the first yoke 10 and fixed to the disk portion 12 by adhesive or other methods. The inner diameter of the magnet 30 matches the outer diameter of the positioning portion 16 of the first yoke 10. The magnet 30 is positioned radially by fitting the inner peripheral surface of the magnet 30 into the outer peripheral surface of the positioning portion 16. This forms a radial gap between the magnet 30 and the cylindrical portion 14 of the first yoke 10. The outer diameter of the magnet 30 is larger than the outer diameter of the disk portion 12. Therefore, when the first yoke 10 is viewed from the Z1 side toward the Z2 direction along the Z direction (hereinafter also referred to as a plan view), the magnet 30 protrudes radially outward from the periphery of the disk portion 12. The central axis of the magnet 30 is coaxial with the central axis of the cylindrical portion 14.

[0025] The magnet 30 is magnetized so that the surface facing the disk portion 12 is a magnetic pole (N pole in this embodiment). That is, the magnet 30 is magnetized along the Z direction (height direction of the magnet 30).

[0026] The second yoke 20 is made of a soft magnetic material such as low-carbon steel or silicon iron. The second yoke 20 controls the flow of magnetic flux from the magnet 30. The second yoke 20 has an annular plate shape. The second yoke 20 is disposed on the Z2 side of the magnet 30 and is fixed to the magnet 30 by adhesive or other means. In other words, the second yoke 20 faces the south pole of the magnet 30. The inner diameter of the second yoke 20 is smaller than the inner diameter of the magnet 30 and larger than the outer diameter of the cylindrical portion 14 of the first yoke 10. In other words, a radial gap is formed between the second yoke 20 and the cylindrical portion 14, and this gap is narrower than the radial gap between the magnet 30 and the cylindrical portion 14 (see FIG. 4). The outer diameter of the second yoke 20 is the same as the outer diameter of the disk portion 12 of the first yoke 10. With the magnet 30 and the second yoke 20 fixed to the first yoke 10, the Z2-side end of the cylindrical portion 14 of the first yoke 10 protrudes in the Z2 direction from the Z2-side end face of the second yoke 20. The central axis of the second yoke 20 is coaxial with the central axis of the cylindrical portion 14.

[0027] The frame 40 is made of a non-magnetic insulating material such as resin and has an annular shape. The frame 40 supports the integrated first yoke 10, second yoke 20, and magnet 30. The frame 40 is configured to include a first horizontal portion 41, a first vertical portion 42, a second vertical portion 43, a second horizontal portion 44, and a third vertical portion 45, all of which are annular plate-shaped. The central axes of the first horizontal portion 41, the first vertical portion 42, the second vertical portion 43, the second horizontal portion 44, and the third vertical portion 45 are all coaxial with the central axis of the cylindrical portion 14.

[0028] The first horizontal portion 41 has a first horizontal surface 41a, which is a plate surface perpendicular to the Z direction, and a second horizontal surface 41b, which is located on the Z2 side of the first horizontal surface 41a. The first horizontal surface 41a and the second horizontal surface 41b are parallel to each other. The inner diameter of the first horizontal portion 41 is smaller than the outer diameter of the second yoke 20, and the outer diameter of the first horizontal portion 41 is larger than the outer diameter of the second yoke 20.

[0029] The first vertical portion 42 has a first vertical surface 42a that is a plate surface parallel to the Z direction and on the radially inner side. The first vertical portion 42 stands in the Z1 direction slightly radially outward from the radial center of the first horizontal surface 41a of the first horizontal portion 41. The inner diameter of the first vertical portion 42, i.e., the inner diameter of the first vertical surface 42a, is equal to the outer diameter of the second yoke 20. The standing height of the first vertical portion 42 is equal to the thickness of the second yoke 20.

[0030] The second vertical portion 43 stands in the Z2 direction from the outer edge of the second horizontal surface 41b of the first horizontal portion 41. The second horizontal portion 44 extends radially outward from the outer edge of the Z2-side end of the second vertical portion 43. The second horizontal portion 44 has a third horizontal surface 44a, which is a plate surface on the Z2 side that is perpendicular to the Z direction. The third vertical portion 45 stands in the Z2 direction from the outer edge of the third horizontal surface 44a of the second horizontal portion 44.

[0031] The frame 40 is disposed on the Z2 side of the second yoke 20 and is fixed to the second yoke 20 by adhesive or other methods. Specifically, the first horizontal surface 41a of the first horizontal portion 41 of the frame 40 is fixed to the lower surface 22 of the second yoke 20, and the first vertical surface 42a of the first vertical portion 42 is fixed to the side surface 24 of the second yoke 20. In this way, the first yoke 10, the magnet 30, the second yoke 20, and the frame 40 are integrated. Hereinafter, this integrated unit will be collectively referred to as the movable portion 5.

[0032] The base 70 is formed by pressing a plate-like metal with high thermal conductivity, such as an aluminum alloy, and has a generally circular plate shape. The base 70 has, from the center toward the outside, a coil fixing portion 71, a circuit board mounting portion 72, a cushion mounting portion 73, a cover positioning portion 74, and a bolt insertion portion 75. The following description will be based on the cushion mounting portion 73 and a cushion mounting surface 73a, which is the Z2-side surface of the cushion mounting portion 73. That is, the description will be based on the state when the base 70 is viewed from the Z2 side toward the Z1 direction along the Z direction (hereinafter also referred to as a bottom view). The cushion mounting surface 73a is a plane perpendicular to the axis X. A heat-dissipating paint 83 is applied to the entire Z2-side surface (surface) of the base 70 (see FIGS. 3 and 4).

[0033] As shown in Fig. 3, the cushion mounting part 73 has a generally C-shape with a portion of the ring missing when viewed from the bottom. An annular cushion 95 made of a resilient material such as hard sponge is fixed to the cushion mounting surface 73a of the cushion mounting part 73 by adhesive or other methods (see Fig. 4). By providing the cushion 95, when attaching the vibrator 1 to the vibrated object (not shown), the cushion 95 absorbs any irregularities on the surface of the vibrated object, allowing the vibrator 1 to be stably fixed to the vibrated object.

[0034] The board mounting portion 72 is recessed toward the Z1 side relative to the cushion mounting portion 73. The Z2-side surface of the board mounting portion 72 includes an annular surface 72a located radially inward relative to the cushion mounting portion 73, and a board mounting surface 72b connected to the annular surface 72a and extending radially outward from the annular surface 72a. The annular surface 72a and the board mounting surface 72b are flush with each other. The distance from the center of the base 70 to the board mounting surface 72b is the same as the distance from the center of the base 70 to the cushion mounting surface 73a of the cushion mounting portion 73. That is, the missing portion of the ring of the cushion mounting portion 73 is caused by the board mounting surface 72b being located in the missing portion. The board 90 is fixed to the board mounting surface 72b by adhesive or other methods. Two through holes 72c are located near the boundary between the annular surface 72a and the board mounting surface 72b of the board mounting portion 72. Furthermore, a protrusion 72d extending in the Z2 direction is formed on the board mounting surface 72b. The protrusions 72d are fitted into positioning holes 92 formed in the substrate 90, thereby positioning the substrate 90.

[0035] The coil fixing portion 71 has a cylindrical shape with a bottom that is recessed toward the Z1 side relative to the board mounting portion 72. The coil fixing portion 71 is disposed radially inside the annular surface 72a of the board mounting portion 72. In other words, the coil fixing portion 71 protrudes toward the Z1 side relative to the Z1 side surface of the cushion mounting portion 73 (see FIG. 2). The outer diameter of the coil fixing portion 71 is the same as the inner diameter of the cylindrical bobbin 51 of the coil unit 50. The bobbin 51 is fitted onto the coil fixing portion 71 and fixed by a method such as adhesion, thereby fixing the coil unit 50 to the coil fixing portion 71 (see FIG. 4).

[0036] The cover positioning portion 74 is recessed toward the Z1 side relative to the cushion mounting portion 73. The cover positioning portion 74 is disposed radially outward of the cushion mounting portion 73 and has an annular shape. The depth of the recess of the cover positioning portion 74 toward the Z1 side is deeper than the depth of the recess of the board mounting portion 72 toward the Z1 side (see FIG. 4). The outer diameter of the cover positioning portion 74 is the same as the inner diameter of the cover main body 82 of the cover 80, which will be described later. On the Z1 side of the base 70, the cover 80 is positioned relative to the base 70 by fitting the cover 80 onto the cover positioning portion 74.

[0037] The bolt insertion portion 75 is disposed radially outward of the cover positioning portion 74. Three bolt insertion portions 75 are disposed along the circumferential direction of the cover positioning portion 74. Specifically, one bolt insertion portion 75 is disposed at a position that is point-symmetrical with respect to the board mounting portion 72 with respect to the center of the base 70, and one bolt insertion portion 75 is disposed at each of the positions that form central angles of 120 degrees and 240 degrees from there along the circumferential direction (see FIGS. 2 and 3). Each bolt insertion portion 75 has one bolt insertion hole 75a formed along the Z direction.

[0038] The Z2-side surface on which the bolt insertion holes 75a are formed is located on the Z1 side of the cushion mounting surface 73a, and on the Z2 side of the bottom surface of the cover positioning portion 74. An outer wall 76 parallel to the Z direction is formed on the outer edge of the base 70, including the outer edge of the bolt insertion portions 75, except for the portion that intersects with the board mounting surface 72b of the board mounting portion 72. An end surface 76a on the Z2 side of the outer wall 76 (a surface perpendicular to the Z direction) is located on the same plane as the cushion mounting surface 73a.

[0039] The substrate 90 has a substantially rectangular plate shape and is fixed to the substrate mounting surface 72b of the substrate mounting portion 72 by adhesive or other methods. A positioning hole 92 is formed in the center of the substrate 90. A protrusion 72d formed on the substrate mounting portion 72 fits into the positioning hole 92, thereby positioning the substrate 90 relative to the base 70. In a plan view, a portion of the substrate 90 is exposed and protrudes radially outward from the base 70. A driver IC (not shown) and other components that drive the vibrator 1 are mounted on the substrate 90.

[0040] The coil unit 50 has a bobbin 51, a holding member 52, and a coil 53. The bobbin 51 has a cylindrical shape and is made of a metal such as an aluminum alloy. In this embodiment, the bobbin 51 is formed by rolling an aluminum alloy plate into a cylindrical shape. The holding member 52 is made of an insulating material such as senka paper, and has an adhesive applied to one side. The holding member 52 is affixed to the outer peripheral surface of the bobbin 51, which is formed by rolling a plate. This allows the bobbin 51 to maintain its cylindrical shape. The holding member 52 covers approximately two-thirds of the Z-direction length of the bobbin 51 from the Z2-side end of the bobbin 51 toward the Z1 side.

[0041] The coil 53 is a self-bonding copper wire having a circular or rectangular cross section, with an insulating layer and a bonding layer disposed in this order around the copper wire. The coil 53 is wound around a portion of the bobbin 51 where the holding member 52 is not attached. In this embodiment, the coil 53 is wound in two layers. Specifically, the winding starts from the Z1-side end of the holding member 52 and continues in the Z1 direction, then turns back in the Z2 direction at the Z1-side end of the bobbin 51 and continues to the starting point of the winding. When the coil unit 50 is heated to a high temperature after the winding of the coil 53 is completed, the bonding layers of the copper wire soften and bond together, and the coil 53 is fixed in its wound shape.

[0042] As described above, the inner diameter of the bobbin 51 is the same as the outer diameter of the coil fixing portion 71 of the base 70. The bobbin 51 is fitted onto the coil fixing portion 71 and fixed by a method such as adhesive, thereby fixing the coil unit 50 to the base 70. In other words, the coil unit 50 is disposed on the Z1 side of the base 70.

[0043] Two lead wires 53a, which are copper wires at both ends of the coil 53, are inserted into two through holes 72c formed in the board mounting portion 72 of the base 70, respectively, and are electrically connected to wiring (not shown) on the board 90 by a method such as soldering. Note that in FIG. 4, the lead wire 53a is illustrated as being arranged overlapping the holding member 52, but in reality, it is arranged between the bobbin 51 and the holding member 52. In other words, the lead wire 53a is in close contact with the bobbin 51 and the holding member 52. By arranging the lead wire 53a between the bobbin 51 and the holding member 52, the lead wire 53a can be fixed by the holding member 52.

[0044] The damper 60 supports the movable part 5 so that it can swing relative to the base 70. In this embodiment, the damper 60 is made of a first damper 61 and a second damper 62. The damper 60 is made of a metallic spring material such as SUS for springs.

[0045] The first damper 61 includes a first radially inner annular portion 61a, a first radially outer annular portion 61b, and spring arms 61c connecting the first radially inner annular portion 61a and the first radially outer annular portion 61b. The first radially inner annular portion 61a has an annular plate shape and is fixed to the holding member 52 of the coil unit 50 by adhesive or other methods. The first radially outer annular portion 61b has an annular plate shape and is fixed to the second horizontal surface 41b of the first horizontal portion 41 of the frame 40 by adhesive or other methods. Three spring arms 61c are arranged between the first radially inner annular portion 61a and the first radially outer annular portion 61b at equal circumferential positions. That is, the spring arms 61c are arranged at 120-degree intervals with respect to the center of the first damper 61. The spring arms 61c have an S-shape in plan view. The center of the first damper 61 is located on the central axis of the cylindrical portion 14.

[0046] The second damper 62 includes a second radially inner annular portion 62a, a second radially outer annular portion 62b, and an annular spring portion 62c connecting the second radially inner annular portion 62a and the second radially outer annular portion 62b. The second radially inner annular portion 62a has an annular plate shape and is fixed to the holding member 52 of the coil unit 50 by adhesive or other methods. The second radially outer annular portion 62b has an annular plate shape and is fixed to the third horizontal surface 44a of the second horizontal portion 44 of the frame 40 by adhesive or other methods. The annular spring portion 62c is disposed around the entire circumference in the circumferential direction between the second radially inner annular portion 62a and the second radially outer annular portion 62b. That is, the second damper 62 has a circular plate shape in a plan view with a through-hole formed in the center through which the coil unit 50 is inserted. When a cross section perpendicular to the plate surface passing through the center of the disk is viewed in a direction perpendicular to the Z direction, the annular spring portion 62c has a sinusoidal shape in which curves convex in the Z2 direction and curves convex in the Z1 direction relative to the second radially outer annular portion 62b are alternately arranged. The center of the second damper 62 is located on the central axis of the cylindrical portion 14.

[0047] When the movable part 5 is supported by the coil unit 50 via the damper 60, the coil unit 50 enters the gap between the second yoke 20 and the cylindrical part 14 of the first yoke 10, and the coil 53 faces the inner peripheral surface of the second yoke 20. At this time, the coil unit 50 is not in contact with either the second yoke 20 or the cylindrical part 14. In this state, the damper 60 undergoes elastic deformation, causing the movable part 5 to oscillate in the Z direction relative to the coil unit 50 (base 70), and the vibrator 1 vibrates.

[0048] The cover 80 is made of a metal with high thermal conductivity, such as an aluminum alloy. The cover 80 has a cover main body 82 and a protrusion 84. The cover main body 82 and the protrusion 84 are integrally formed. A heat-dissipating paint 83 is applied to the entire surface (front surface) of the cover main body 82 on the Z1 side (see FIGS. 2 to 4).

[0049] The cover body 82 has a generally cylindrical shape with a bottom, and is joined to the base 70 by adhesive or other methods while being positioned relative to the base 70 by fitting onto the cover positioning portion 74 of the base 70. The first yoke 10, the second yoke 20, the magnet 30, the frame 40, the coil unit 50, and the damper 60 are housed in the internal space 81 formed by the cover body 82 and the base 70. An O-ring (not shown) is disposed at the joint between the cover body 82 and the base 70, thereby ensuring watertightness of the internal space 81. Note that an O-ring need not be disposed as long as the watertightness of the internal space 81 is ensured.

[0050] The protrusion 84 is formed so as to protrude from the cover main body 82 toward the internal space 81. The protrusion 84 has a cylindrical shape, and the central axis of the protrusion 84 is coaxial with the axis X.

[0051] With the cover 80 joined to the base 70, the protrusion 84 is fitted into and passes through the through hole 15 formed in the first yoke 10, extending from the disc portion 12 to the cylindrical portion 14, and is exposed from the tip of the cylindrical portion 14. At this time, there is a slight gap between the outer peripheral surface of the protrusion 84 and the inner peripheral surface 14a of the cylindrical portion 14 that forms the through hole 15, and the protrusion 84 and the cylindrical portion 14 are not in contact with each other.

[0052] [Vibrator operation] Next, we will explain the operation of the vibrator 1. When a direct current is applied from the outside to the substrate 90 of the vibrator 1, the direct current is converted into an alternating current with a sine wave or square wave by a driver IC or the like mounted on the substrate 90, and the alternating current is applied to the coil 53 of the coil unit 50.

[0053] Meanwhile, in the magnetic circuit formed by the first yoke 10, the second yoke 20, and the magnet 30 of the movable part 5, magnetic flux flowing out from the north pole of the magnet 30 flows through the disk part 12, the cylindrical part 14, and the second yoke 20 of the first yoke 10, and into the south pole of the magnet 30. When the magnetic flux flows from the cylindrical part 14 toward the second yoke 20, it interlinks with the current flowing through the coil 53, and therefore, the alternating current flowing through the coil 53 generates forces in the Z1 direction and the Z2 direction alternately in the movable part 5. This causes the movable part 5 to oscillate along the Z direction, and the vibrator 1 can generate vibrations. That is, the current flowing through the coil 53 of the coil unit 50 acts on the movable part 5 along the Z direction, providing a propulsive force that enables reciprocating propulsion. As shown in FIG. 4, the gap between the outer peripheral surface of the cylindrical portion 14 of the first yoke 10 and the inner peripheral surface of the second yoke 20 is narrower than the gap between the outer peripheral surface of the cylindrical portion 14 and the inner peripheral surface of the magnet 30, so most of the magnetic flux flowing through the cylindrical portion 14 flows to the second yoke 20, which has a low magnetic resistance, and almost no magnetic flux flows directly from the cylindrical portion 14 to the magnet 30.

[0054] When the vibrator 1 continues to operate, a current continues to flow through the coil 53 of the coil unit 50, causing the coil 53 to generate heat. The heat generated in the coil 53 is conducted to the air in the gap between the cylindrical portion 14 of the first yoke 10 and the second yoke 20, raising the temperature of the air in the internal space 81, and is also conducted from the air to the cylindrical portion 14 and the second yoke 20, raising the temperatures of the first yoke 10 and the second yoke 20. Some of the heat conducted to the internal space 81 is conducted to the cover body 82 and base 70 of the cover 80, which are in contact with the internal space 81, and is released to the outside of the vibrator 1 from the surfaces of the cover body 82 and base 70. Furthermore, in this embodiment, the protrusion 84 of the cover 80 is fitted into the through hole 15 of the first yoke 10, so that heat conducted from the internal space 81 to the first yoke 10 is conducted to the protrusion 84 of the cover 80, and then from the protrusion 84 to the cover main body 82, and is then dissipated from the surface of the cover main body 82 to the outside of the vibrator 1. The heat is also conducted from the cover main body 82 and the metal bobbin 51 of the coil unit 50 to the base 70, and is also dissipated from the surface of the base 70. In this embodiment, the heat-dissipating paint 83 is applied to the entire Z1-side surface of the cover main body 82 and the entire Z2-side surface of the base 70, i.e., the entire surface of the vibrator 1 (see FIG. 4), so that heat can be more efficiently dissipated to the outside of the vibrator 1.

[0055] As described above, the vibrator 1 of this embodiment is highly watertight, preventing dust and liquid from entering the internal space 81, and is also able to efficiently release heat generated by energizing the coil 53 to the outside. This prevents damage to the insulating layer and fusion layer of the copper wire of the coil 53 due to heat, even if the vibrator 1 continues to operate.

[0056] Second Embodiment Next, a description will be given of a vibrator 1 according to a second embodiment. This embodiment differs from the first embodiment in that heat-conducting grease 85 is disposed between the inner peripheral surface 14a of the cylindrical portion 14 of the first yoke 10 and the outer peripheral surface of the protruding portion 84 of the cover 80. The other configurations are the same as those of the first embodiment, and therefore detailed descriptions of the same configurations will be omitted.

[0057] In the cover 80 of the vibrator 1 of this embodiment, the diameter of a portion of the protruding portion 84 is reduced, and thermally conductive grease 85 is placed in the gap created by this reduced diameter. The thermally conductive grease 85 contacts both the inner circumferential surface 14a of the cylindrical portion 14 of the first yoke 10 and the outer circumferential surface of the protruding portion 84 of the cover 80. In addition, a pair of O-rings 86 is placed on both sides of the protruding portion 84 in the Z direction, sandwiching the thermally conductive grease 85 therebetween. This prevents the thermally conductive grease 85 from scattering and flowing into the internal space 81.

[0058] Since the thermal conductivity of the thermal conductive grease 85 is higher than that of air, by arranging the thermal conductive grease 85 so that it is in contact with both the cylindrical portion 14 and the protruding portion 84, the heat generated by the coil 53 can be released to the outside of the vibrator 1 more efficiently than in the first embodiment.

[0059] Third Embodiment Next, a description will be given of a vibrator 1 according to a third embodiment. This embodiment differs from the first and second embodiments in that a magnetic fluid 87 is disposed between the inner circumferential surface 14a of the cylindrical portion 14 of the first yoke 10 and the outer circumferential surface of the protruding portion 84 of the cover 80. The other configurations are the same as those of the first and second embodiments, and therefore detailed descriptions of the similar configurations will be omitted.

[0060] In the cover 80 of the vibrator 1 of this embodiment, the diameter of a portion of the protrusion 84 is reduced, and a cylindrical tubular magnet 88 (an example of a second permanent magnet) is disposed in close contact with the entire outer circumferential surface of the reduced diameter portion, and a magnetic fluid 87 is disposed in the gap between the outer circumferential surface of the tubular magnet 88 and the inner circumferential surface 14a of the cylindrical portion 14 of the first yoke 10. The tubular magnet 88 is a permanent magnet such as a ferrite magnet. The magnetic fluid 87 is in contact with both the inner circumferential surface 14a of the cylindrical portion 14 and the outer circumferential surface of the tubular magnet 88. Note that, because the magnetic fluid 87 is attracted to the tubular magnet 88, there is no need to place O-rings or the like on both sides of the magnetic fluid 87 in the Z direction.

[0061] Since the magnetic fluid 87 has a higher thermal conductivity than air, by arranging the magnetic fluid 87 so that it is in contact with both the cylindrical portion 14 and the cylindrical magnet 88 that is in close contact with the protruding portion 84, the heat generated by the coil 53 can be more efficiently released to the outside of the vibrator 1. In addition, the magnetic fluid 87 also functions as a sliding bearing, allowing the movable portion 5 to oscillate smoothly along the Z direction.

[0062] Other Embodiments (1) In the above embodiment, the damper 60 is composed of the first damper 61 and the second damper 62. However, the damper 60 may be composed of one member or three or more members.

[0063] (2) In the above embodiment, the heat-dissipating paint 83 is applied to the entire Z1-side surface of the cover body 82 and the entire Z2-side surface of the base 70. However, the heat-dissipating paint 83 may not be applied to one or both of the cover body 82 and the base 70. Furthermore, the heat-dissipating paint 83 may be applied only to a portion of the surface, rather than the entire surface.

[0064] (3) In the above embodiment, the frame 40 is made of a non-magnetic insulating material such as resin, but it may also be made of a non-magnetic metal such as tungsten. Generally, by using a metal with a higher specific gravity than resin, the inertia of the movable part 5 during oscillation can be increased, and the vibration amount of the vibrator 1 can be increased.

[0065] (4) In the above embodiment, the first yoke 10 has a through hole 15, and the protrusion 84 of the cover 80 passes through the through hole 15 and is exposed from the tip of the cylindrical portion 14 of the first yoke 10. However, this is not limited to this. The protrusion 84 does not have to be exposed from the tip of the cylindrical portion 14. Furthermore, the through hole 15 may be a bottomed hole that does not pass through the first yoke 10.

[0066] (5) In the above embodiment, the outer diameter of the magnet 30 is larger than the outer diameter of the disk portion 12 of the first yoke 10 and the outer diameter of the second yoke 20. However, the outer diameter of the magnet 30 may be the same as or smaller than the outer diameter of the disk portion 12 and the outer diameter of the second yoke 20. Furthermore, the outer diameter of the disk portion 12 and the outer diameter of the second yoke 20 may not be the same but may be different.

[0067] (6) In the above embodiment, the cover 80 is formed integrally with the cover body 82 and the protrusion 84, but this is not limited to this. The cover 80 may be formed by forming the cover body 82 and the protrusion 84 separately and then integrating them by welding or other methods.

[0068] (7) In the above embodiment, the cover 80 and the base 70 are made of a metal with high thermal conductivity, such as an aluminum alloy, but this is not limiting. At least one of the cover 80 and the base 70 may be made of carbon, which has high thermal conductivity, or a resin containing carbon.

[0069] (8) In the above embodiment, the bobbin 51 is formed by rolling an aluminum alloy plate into a cylindrical shape and maintaining the cylindrical shape with the holding member 52. However, this is not limited to this. For example, the bobbin 51 may be formed by removing the center of a cylindrical metal piece by cutting.

[0070] (9) In the above embodiment, an alternating current is applied to the coil 53, but this is not limiting. For example, instead of an alternating current, a pulse-shaped current that flows in only one direction at predetermined intervals may be used. In this case, when no current is applied, the restoring force of the elastic deformation of the damper 60 causes the movable part 5 to move in the opposite direction to when a current is applied, thereby achieving oscillation of the movable part 5. [Industrial Applicability]

[0071] The present disclosure is applicable to a vibration exciter. [Explanation of symbols]

[0072] 5 ; Movable part 10: 1st York (York) 14a: Inner surface 15: Through hole (hole) 30: Magnet (first permanent magnet) 40: Frame 50: Coil unit (coil part) 51: Bobbin 53: Coil 60: Damper (damper part) 70: Bass 80: Cover 83: Heat-dissipating paint 84: Protrusion 85: Thermal grease 87:Magnetic fluid 88: Cylindrical magnet (second permanent magnet)

Claims

1. a movable part including a first permanent magnet, a yoke that controls a flow of magnetic flux flowing out from the first permanent magnet, and a frame that supports the first permanent magnet and the yoke; a coil portion that is energized in a direction interlinking with the magnetic flux and applies a thrust force to the movable portion; a base for fixing the coil portion; a damper portion that supports the movable portion so that the movable portion can be reciprocated relative to the coil portion; a cover joined to the base and accommodating the movable portion, the coil portion, and the damper portion therein; The yoke has a hole extending in a direction along the acting direction of the thrust force, The cover has a protrusion that fits into the hole.

2. The vibrator according to claim 1 , wherein the cover including the protrusion is made of metal.

3. 3. The vibrator according to claim 1, wherein thermally conductive grease is disposed between the inner peripheral surface of the hole of the yoke and the protrusion.

4. a second permanent magnet is disposed on at least a portion of the protrusion; 3. The vibrator according to claim 1, wherein a magnetic fluid is disposed between an inner peripheral surface of the hole of the yoke and the second permanent magnet.

5. the coil portion includes a bobbin fixed to the base and a coil wound around the bobbin, The vibrator according to claim 1 or 2, wherein the bobbin and the base are made of metal.

6. 3. The vibrator according to claim 1, wherein a heat-dissipating paint is applied to a surface of at least one of the cover and the base.

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