Multi-functional type vibration actuator

Abstract

To provide a multi-functional type vibration actuator for enabling an acoustic generation function and a vibration generation function to be respectively exhibited stably.SOLUTION: A multi-functional type vibration actuator includes: a case 32; a coil 22 stored in the case 32; a diaphragm 24 connected to the coil 22; a movable element 26 stored in the case 32 so as to be vibrated; and a leaf spring 28 which is attached to the case 32 and to which the movable element 26 is attached. The movable element 26 is arranged to allow an outer peripheral surface 26A1 of a maximum diameter part 26A to be arranged at a clearance G for limiting an air movement amount with respect to an inner peripheral surface 32B of the case 32. The case 32 includes a swelling part 38 which swells outward in a radial direction while including an open end part 32A and faces an outer peripheral part 24B of the diaphragm 24. A through-hole 32H is formed in the swelling part 38. The through-hole 32H is formed to be closer to an open end part 32A than the clearance G in the case 32.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a multi-function vibration actuator. [Background technology]

[0002] The following Patent Document 1 discloses a technology related to a multi-function vibration actuator. The multi-function vibration actuator of this prior art includes a magnetic circuit section (movable element) that forms a magnetic path, a suspension (leaf spring) that supports the magnetic circuit section, a diaphragm (diaphragm) that is arranged opposite the magnetic circuit section, a voice coil that is provided on the diaphragm and inserted into a magnetic gap formed in the magnetic circuit section, and a housing that contains the magnetic circuit section. Here, the magnetic circuit section is arranged such that a clearance that limits the amount of air movement is present between the side surface of the magnetic circuit section and the inner surface of the housing.

[0003] Moreover, FIG. 7 of Patent Document 1 below shows a configuration in which a through hole is provided on the side of the housing to allow air to freely flow in and out. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4146346 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in this configuration, the through-hole includes a portion of the side of the housing that is lower than the suspension, and when the upper end of the side of the magnetic circuit is displaced to a position corresponding to the through-hole during vibration of the magnetic circuit, the length of the air flow path that limits the amount of air movement cannot be maintained, and air near the upper end of the side of the magnetic circuit leaks out of the through-hole. If air leaks in this way, the viscous resistance of the air flowing in and out of the clearance between the side of the magnetic circuit and the inner surface of the housing is reduced accordingly. Also, if the through-hole is blocked by the mover, it becomes difficult for the diaphragm to move, which affects the acoustic performance.

[0006] In consideration of the above, an object of the present invention is to provide a multifunction vibration actuator that can stably exert both the sound generating function and the vibration generating function. [Means for solving the problem]

[0007] A multi-function vibration actuator of a first embodiment comprises a case having an open end on one side, a coil housed in the case and arranged so that its axial direction is along the depth direction of the case, a vibration plate arranged on the one side of the case and connected to the coil and capable of vibrating in the axial direction of the coil, a movable element housed in the case and arranged with an outer peripheral surface separated from the inner peripheral surface of the case by a clearance that limits the amount of air movement, the movable element including a magnet and vibrating along the vibration direction of the vibration plate when current is passed through the coil, and a leaf spring attached to the case and to which the movable element is attached, the case having a protruding portion that protrudes radially outward including the open end on the one side and faces the outer peripheral portion of the vibration plate, a through hole formed in the protruding portion, the through hole being formed on the open end side of the case relative to the clearance.

[0008] In the multi-function vibration actuator of the first embodiment, a coil is housed in a case having an open end on one side, the coil being arranged so that its axial direction is along the depth direction of the case. A vibration plate is arranged on the one side of the case, and the vibration plate is connected to the coil and can vibrate in the axial direction of the coil. A mover is housed in the case, and the outer circumferential surface of the mover is arranged with a clearance that limits the amount of air movement from the inner circumferential surface of the case. The mover includes a magnet, and vibrates in the vibration direction of the vibration plate by passing electricity through the coil. Furthermore, a leaf spring is attached to the case, and the mover is attached to the leaf spring. As described above, the multi-function vibration actuator has a sound generation function that can vibrate the vibration plate to generate sound by passing electricity through the coil, and a vibration generation function that can vibrate the mover to generate vibration, and the mover vibrates while suppressing its amplitude, so that vibrations with a small change in acceleration relative to the change in frequency can be generated.

[0009] Moreover, the case is formed with a protruding portion that includes an open end on one side and protrudes outward in the radial direction and faces the outer periphery of the diaphragm, and a through hole is formed in the protruding portion. The through hole is formed on the case closer to the open end side than the clearance. This allows air to enter and exit through the through hole in the protruding portion when the diaphragm vibrates, so that the vibration characteristics of the diaphragm can be maintained while the amount of air movement is limited by the clearance between the outer periphery of the mover and the inner periphery of the case. Moreover, in this first aspect, it is easier to ensure the damping function when the mover vibrates compared to, for example, a comparison in which a through hole is formed in the bottom wall of the case. Furthermore, by adopting this first aspect, the length of the air flow path that limits the amount of air movement when the mover vibrates can be maintained and set to be long. Therefore, it is possible to increase the viscous resistance of the air whose amount of movement is limited when the mover vibrates. Furthermore, by forming the through hole in the protruding portion, the mover does not block the through hole when the mover vibrates. Therefore, even if the sound generating function and the vibration generating function are used simultaneously, each function can be stably exhibited.

[0010] A multifunction vibration actuator of a second aspect is the same as the first aspect, in which an outer periphery of the leaf spring is attached to the case, and a central portion of the leaf spring is attached to the movable element on the side opposite to the vibration plate.

[0011] In the multifunction vibration actuator of the second aspect, the span of the leaf spring can be changed by changing the area of ​​the part of the mover opposite the diaphragm that avoids contact with the movable part of the leaf spring. Also, by changing the span of the leaf spring, the suspension characteristics can be easily adjusted.

[0012] A multi-function vibration actuator of a third aspect is the first or second aspect, wherein the through hole penetrates the case in a radial direction relative to the protruding portion.

[0013] In the multi-function vibration actuator of the third aspect, the through-hole penetrates in a direction parallel to the radial direction of the case relative to the protruding portion, so that it is possible to reduce the amount of protrusion of the protruding portion radially outward.

[0014] The multi-function vibration actuator of the fourth aspect is the second aspect, in which the center of the leaf spring is attached to the center of the other side of the bottom surface of the mover, and the outer peripheral surface of the bottom surface of the mover is at least one of a tapered surface that slopes toward the other side as it approaches radially inward, and a connection surface that is connected to the center of the bottom surface via a step. Note that the "other side" refers to the opposite side to the "one side" described in the first aspect.

[0015] In the multifunction vibration actuator of the fourth aspect, the center of the leaf spring is attached to the center of the bottom surface of the other side of the mover, so the span of the leaf spring is long, and soft suspension characteristics can be achieved. Also, the outer peripheral surface of the bottom surface of the mover is at least one of a tapered surface that slopes toward the other side as it moves radially inward, and a connection surface that is connected to the center of the bottom surface via a step, so that the mover can be prevented from coming into contact with the span of the leaf spring when the mover vibrates.

[0016] A multi-function vibration actuator according to a fifth aspect is any one of the first to fourth aspects, wherein a recessed groove is formed on the outer circumferential surface of the mover, extending in the circumferential direction.

[0017] In the multi-function vibration actuator of the fifth aspect, when air moves between the outer peripheral surface of the mover and the inner peripheral surface of the case in the vibration direction of the mover, an expansion loss can be generated in the portion where the flow path cross-sectional area increases abruptly, and a contraction loss can be generated in the portion where the flow path cross-sectional area decreases abruptly. In other words, when air moves as described above, a pressure loss can be generated, so that the viscous resistance of the moving air can be increased. This can improve the damping function when the mover vibrates.

[0018] A multi-function vibration actuator according to a sixth aspect is the fifth aspect, wherein the groove is formed over the entire outer circumferential surface of the mover.

[0019] In the multi-function vibration actuator of the sixth aspect, when air moves between the outer surface of the movable element and the inner surface of the case in the vibration direction of the movable element, pressure loss can be generated around the entire circumference of the air flow path, and the viscous resistance of the moving air can be increased around the entire circumference of the air flow path.

[0020] A multifunction vibration actuator according to a seventh aspect is the actuator of the fifth or sixth aspect, wherein the grooves are formed in a plurality of parallel grooves spaced apart from one another in the vibration direction of the mover.

[0021] In the multi-function vibration actuator of the seventh aspect, when air moves between the outer peripheral surface of the movable element and the inner peripheral surface of the case in the vibration direction of the movable element, a larger pressure loss can be generated, and the viscous resistance of the moving air can be further increased.

[0022] The multi-function vibration actuator of the eighth aspect is any one of the first to seventh aspects, in which the component part on the outer periphery of the mover is formed of a separate member from the main body part of the mover.

[0023] In the multifunction vibration actuator of the eighth aspect, the components on the outer periphery of the mover can be manufactured with high precision. Also, by replacing the separate parts, it is possible to adjust the resonance frequency of the vibration, allowing for product variation. Effect of the Invention

[0024] As described above, the multi-function vibration actuator of the present invention has the excellent effect of being able to stably exert both the sound generating function and the vibration generating function. [Brief description of the drawings]

[0025] [Figure 1] 1 is a perspective view showing a multi-function vibration actuator according to a first embodiment. [Diagram 2] 2 is a cross-sectional view showing a state cut along line 2-2 in FIG. 1. [Diagram 3] 5 is a cross-sectional view showing a portion of a multi-function vibration actuator according to a second embodiment. FIG. [Figure 4] FIG. 11 is a cross-sectional view showing a portion of a multi-function vibration actuator according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] [First embodiment] The multifunction vibration actuator according to the first embodiment will be described with reference to Figures 1 and 2. Figure 1 shows a perspective view of a multifunction vibration actuator 10 according to the first embodiment. Figure 2 shows a cross-sectional view taken along line 2-2 in Figure 1.

[0027] (composition) We will now explain the configuration of the multifunction vibration actuator 10 shown in Fig. 1. The multifunction vibration actuator 10 is a small device equipped with an acoustic generation function that generates sound and a vibration generation function that generates vibrations for bodily sensation, and can be used in portable terminal devices such as mobile phones.

[0028] As shown in Fig. 2, the multi-function vibration actuator 10 has a case 32 having an open end 32A on one side (the side in the direction of the arrow Z). The case 32 is, for example, composed of a first component member (also called a "rear frame") 34 and a second component member (also called a "frame") 36. The first component member 34 is formed in a bottomed cylindrical shape and includes a bottom wall portion 34A and a peripheral wall portion 34B formed continuously with the outer peripheral end portion of the bottom wall portion 34A, and also includes a protruding wall portion 34C protruding radially outward from a portion of the peripheral wall portion 34B opposite to the bottom wall portion 34A side. The protruding wall portion 34C includes a convex portion 34C1 protruding to the one side (the side in the direction of the arrow Z) at the tip end in the protruding direction. The second component member 36 is formed in a short cylindrical shape, and is attached to the one side (the side in the direction of the arrow Z) of the radially outer portion (portion including the convex portion 34C1) of the protruding wall portion 34C of the first component member 34. The protruding wall portion 34C and the second component member 36 form the protruding portion 38 of the case 32 of the first embodiment. The protruding portion 38 is a portion of the case 32 that protrudes radially outward.

[0029] An end portion of the second component member 36 on the opposite side to the first component member 34 side (the upper side in FIG. 2) constitutes an open end portion 32A on the one side (the side in the direction of the arrow Z) of the case 32. In the following, when describing the parts constituting the first component member 34 and the second component member 36, they will be described as parts of the case 32.

[0030] A protector 18 is attached to the open end 32A of the case 32. The protector 18 is disposed so as to cover the open side of the case 32. The protector 18 has a flat plate portion 18A provided at a position that blocks the open side of the case 32, and a plurality of sound emission holes 18H are formed penetrating the flat plate portion 18A (see FIG. 1).

[0031] A coil 22 (shown in a simplified form in the figure) is housed in the case 32. The coil 22 is arranged so that its axial direction is along the depth direction of the case 32 (so that it is in the same direction as the depth direction of the case 32). A power supply wiring (not shown) for supplying power to the coil 22 is connected to the coil 22.

[0032] Furthermore, a diaphragm 24 connected to the coil 22 is disposed on the one side (the side in the direction of the arrow Z) of the case 32. The diaphragm 24 is disposed closer to the protector 18 than the coil 22 is, and disposed so as to face the flat plate portion 18A of the protector 18. The attachment portion 24A provided on the outer peripheral end side of the diaphragm 24 is sandwiched and attached between the case 32 and the protector 18 over the entire periphery. The attachment portion 24A provided on the outer peripheral end side of the diaphragm 24 may be attached to the case 32 in another attachment form. The diaphragm 24 is capable of vibrating in the axial direction of the coil 22.

[0033] The case 32 also houses the mover 26 (schematically shown in the figure). The outer peripheral surface 26A1 of the maximum diameter portion 26A, which is a part (most part) of the outer peripheral surface 26S of the mover 26, is disposed with a clearance G that limits the amount of air movement from the inner peripheral surface 32B of the case 32. The clearance G can be regarded as a narrow air gap. The reference character L in FIG. 2 indicates the length of the clearance G. In addition, when viewed from the direction of FIG. 2, the extension direction of the outer peripheral surface 26A1 of the maximum diameter portion 26A of the mover 26 and the extension direction of the inner peripheral surface 32B of the case 32 that forms the clearance G between the outer peripheral surface 26A1 of the maximum diameter portion 26A of the mover 26 are both the same as the depth direction of the case 32.

[0034] The mover 26 has a magnetic circuit section including a magnet, is supported by a leaf spring 28 described later, and is vibrated in the vibration direction of the diaphragm 24 by passing electricity through the coil 22. Although detailed illustration is omitted, in this embodiment, the mover 26 includes a ferromagnetic cylindrical yoke with a bottom and a disk-shaped plate made of a ferromagnetic material in addition to the magnet, and the magnet is placed on the inner periphery of the yoke, and the plate is placed on the magnet. To supplement, the multi-function vibration actuator 10 of this embodiment has an internal magnet type magnetic circuit section in which a magnet constituting a part of the mover 26 is placed on the inner periphery of the coil 22. In addition, the outer periphery 26A1 of the maximum diameter part 26A, which is placed in the mover 26 with a clearance G that limits the amount of air movement from the inner periphery 32B of the case 32, is the outer periphery of the yoke. A known magnetic circuit section disclosed in, for example, Japanese Patent No. 4146346 can be applied to the mover 26.

[0035] The multifunction vibration actuator 10 also has a leaf spring 28 that is attached to the case 32 and to which the mover 26 is attached. Although the external shape of the leaf spring 28 is not shown in the figures, the leaf spring 28 includes a large diameter annular portion 28A that is attached to the case 32, a small diameter annular portion 28C that is provided on the inner periphery side away from the large diameter annular portion 28A and to which the mover 26 is attached, and a connecting portion 28B that connects the large diameter annular portion 28A and the small diameter annular portion 28C.

[0036] The large diameter annular portion 28A is attached to the end surface of the peripheral wall portion 34B of the case 32 opposite to the bottom wall portion 34A side. The small diameter annular portion 28C is attached to the portion of the movable element 26 on the vibration plate 24 side. The surface 26B of the movable element 26 that is on the outer periphery side of the portion attached to the small diameter annular portion 28C and faces the leaf spring 28 side is set at a position away from the connecting portion 28B by a predetermined distance so as not to come into contact with the connecting portion 28B of the leaf spring 28 when the movable element 26 vibrates. The connecting portion 28B is configured to include, for example, a plurality of arms extending in the same direction along the circumferential direction between the large diameter annular portion 28A and the small diameter annular portion 28C. The leaf spring 28 applied to the multi-function vibration actuator 10 is sometimes called a suspension, and a publicly known one such as that disclosed in Japanese Patent No. 4146346 can be applied, so a detailed description of the leaf spring 28 is omitted.

[0037] The protruding wall portion 34C of the case 32 protrudes from an end portion 32X on the vibration plate 24 side of a portion of the case 32 that may face the outer peripheral surface 26A1 of the maximum diameter portion 26A with a clearance G when the mover 26 vibrates, and faces the outer peripheral portion 24B of the vibration plate 24. The protruding wall portion 34C of the case 32 has a through hole 32H formed therethrough in a direction along the vibration direction of the mover 26. That is, the through hole 32H is formed on the open end 32A side of the clearance G in the case 32. To explain further, the through hole 32H is formed in a portion of the case 32 between a portion located on one side (arrow Z direction side) of a portion that faces the outer peripheral surface 26A1 of the maximum diameter portion 26A of the mover 26 with a clearance G when the mover 26 vibrates and the open end 32A on the one side (arrow Z direction side), and in a portion located on the other side (opposite side to the arrow Z direction side) of the vibration plate 24.

[0038] Through holes 32H are formed to facilitate movement of diaphragm 24 and suppress an increase in resonance frequency, and allow air to move inside and outside case 32 when diaphragm 24 vibrates. A plurality of through holes 32H (four, for example) are set to be arranged at equal intervals in the circumferential direction of case 32.

[0039] (Action and effect) Next, the operation and effects of the first embodiment will be described.

[0040] 2, when an electric signal is applied to the coil 22, the coil 22 vibrates the diaphragm 24 by electromagnetic induction to generate sound. The sound generated by the vibration of the diaphragm 24 is transmitted to the outside through the multiple sound emission holes 18H.

[0041] When an electric signal is applied to the coil 22, the mover 26 having a magnetic circuit vibrates up and down due to electromagnetic induction. When the mover 26 vibrates up and down, the air in the case 32 tries to move between the space S1 between the diaphragm 24 and the mover 26 and the space S2 between the mover 26 and the bottom wall 34A of the case 32 through the clearance G. On the other hand, the outer peripheral surface 26A1 of the maximum diameter portion 26A of the mover 26 is disposed with respect to the inner peripheral surface 32B of the case 32, separated by the clearance G that limits the amount of air movement, so that the amount of air moving between the two spaces S1 and S2 is limited. The air whose movement is limited tries to stay in each of the spaces S1 and S2, and the air that stays in the spaces S1 and S2 functions as a damper that receives the vibration movement of the mover 26. This controls the amplitude of the up and down vibration of the mover 26, and the multi-function vibration actuator 10 can generate vibration with a small amount of change in acceleration relative to the amount of change in frequency.

[0042] In addition, the case 32 is formed with a protruding portion 38 that includes the open end 32A on one side and protrudes outward in the radial direction and faces the outer circumferential portion 24B of the vibration plate 24, and a through hole 32H is formed in the protruding portion 38. The through hole 32H is formed on the open end 32A side of the case 32 from the clearance G. This allows air to enter and exit through the through hole 32H of the case 32 when the vibration plate 24 vibrates, so that the vibration characteristics of the vibration plate 24 can be maintained good while restricting the amount of air movement by the clearance G between the outer circumferential surface 26A1 of the maximum diameter portion 26A of the mover 26 and the inner circumferential surface 32B of the case 32. In addition, according to the configuration of this embodiment, it is easier to ensure the damping function when the mover 26 vibrates, compared to a comparative example in which a through hole is formed in the bottom wall portion (34A) of the case (32).

[0043] In addition, in this embodiment, by forming the through hole 32H in the protruding portion 38, the position where the through hole 32H is formed can be shifted from the position where the clearance G is formed, and the mover 26 does not block the through hole 32H when vibrating. Here, for example, in the case where a portion corresponding to the protruding portion 38 is not formed as a comparison structure and the through hole is arranged at a position where it can be blocked by the mover, if the mover is additionally vibrated at a low frequency when the diaphragm is vibrated to generate sound, the moment the mover blocks the through hole, the lowest resonance frequency (F0) becomes high and the sound pressure becomes low. In this way, in the comparison structure, the sound quality changes due to the influence of the movement of the mover. On the other hand, in this embodiment, the mover 26 does not block the through hole 32H, so such a problem does not occur. Therefore, in this embodiment, even if the sound generating function and the vibration generating function are used simultaneously, each function can be stably exhibited.

[0044] In addition, in the configuration of this embodiment, the length of the air flow path that limits the amount of air movement when the movable member 26 is vibrating (i.e., the length in the vertical direction in the figure of the portion where the clearance G is formed) can be maintained. Here, the length of the air flow path that limits the amount of air movement will also be described. For example, in a configuration in which a portion corresponding to the protruding portion 38 of this embodiment is not provided in the case and the through hole is located in the portion corresponding to the peripheral wall portion 34B of this embodiment and on the side of the position where the clearance (G) is formed (lower in the figure) than the leaf spring (28), it is possible to shorten the air flow path direction (the length in the vertical direction in FIG. 2) of the outer circumferential surface (26A1) of the maximum diameter portion (26A) of the movable member (26) so that the outer circumferential surface (26A1) of the maximum diameter portion (26A) of the movable member (26) does not block the through hole. In contrast, in this embodiment, the through hole 32H is formed in the protruding portion 38, and the outer peripheral surface 26A1 of the maximum diameter portion 26A of the mover 26 does not block the through hole 32H. Therefore, compared to the above-mentioned comparative example, it is possible to increase the length of the outer peripheral surface 26A1 of the maximum diameter portion 26A of the mover 26 in the air flow path direction (the vertical length in FIG. 2), and thus to set the length of the air flow path that limits the amount of air movement (i.e., the vertical length in the figure of the portion where the clearance G is formed) to be longer. This makes it possible to increase the viscous resistance of the air flowing in and out of the clearance G when the mover 26 vibrates. As a result, the propagation vibration acceleration at the resonance frequency is suppressed, an effective suspension effect can be obtained, and the vibration performance of the multi-function vibration actuator 10 can be improved.

[0045] Furthermore, since through-hole 32H faces outer periphery 24B of diaphragm 24 and penetrates in a direction along the vibration direction of mover 26 (in other words, in a direction along the vibration direction of diaphragm 24), air can easily flow in and out via through-hole 32H of case 32 when diaphragm 24 vibrates. This makes it possible to easily move diaphragm 24 and suppress an increase in the resonant frequency.

[0046] As described above, the multifunction vibration actuator 10 of this embodiment is capable of stably performing both the sound generating function and the vibration generating function. To add to the vibration generating function, this embodiment provides an effective suspension effect, which further reduces the amount of change in acceleration relative to the amount of change in frequency, thereby expanding the effective vibration frequency band.

[0047] In addition, in this embodiment, the through hole 32H is formed in the protruding portion 38, so that the movable element 26 does not block the through hole 32H even when the movable element 26 vibrates, and therefore the overall height (vertical length in FIG. 2) of the multifunction vibration actuator 10 can be reduced. In addition, in this embodiment, the protruding wall portion 34C protrudes radially outward from one side (arrow Z direction side) of the peripheral wall portion 34B of the case 32, and the end portion of one side (arrow Z direction side) of the peripheral wall portion 34B of the case 32 functions as a base for fixing the leaf spring 28, so that it is possible to reduce the number of fixing parts for the leaf spring 28. Furthermore, in this embodiment, the through hole 32H is formed in the protruding wall portion 34C, so that the penetration direction of the through hole 32H can be the same as the depth direction of the case 32, and therefore a slide mechanism for the through hole 32H is not required in the mold for manufacturing the case 32, and therefore the mold can be simplified, and the cost of the mold for manufacturing the case 32 can be reduced.

[0048] In this embodiment, the part of the mover 26 on the vibration plate 24 side (the upper side in the figure) is fixed to the leaf spring 28, and the fixing position of the mover 26 to the leaf spring 28 is close to the position of the coil 22. Therefore, even if the mover 26 attempts to abnormally vibrate in an oblique direction, it is easy to prevent contact between the mover 26 and the coil 22.

[0049] [Second embodiment] Next, a multi-function vibration actuator according to a second embodiment will be described with reference to Fig. 3. Note that in the second embodiment, components that are substantially the same as those in the first embodiment will be given the same reference numerals and descriptions thereof will be omitted as appropriate.

[0050] 3 shows a cross-sectional view of a portion of a multifunction vibration actuator 40 according to the second embodiment. As shown in FIG. 3, a case 42 of the multifunction vibration actuator 40 has an open end 42A on one side (the side in the direction of the arrow Z), and the diameter dimension (the length in the left-right direction in FIG. 3) is the same as that of the case 32 in the first embodiment (see FIG. 2). As an example, the case 42 is composed of a first component member (also called a "rear frame") 44 and a second component member (also called a "frame") 46. The first component member 44 is formed in a shallow cylindrical shape with a bottom, and includes a bottom wall portion 44A and a base wall portion 44B formed in a short cylindrical shape continuing from the outer peripheral end portion of the bottom wall portion 44A. The second component 46 includes a cylindrical peripheral wall portion 46A attached to an end portion of the base wall portion 44B of the first component member 44 opposite to the bottom wall portion 44A side and disposed at an extended position of the base wall portion 44B, a protruding wall portion 46B protruding radially outward from an end portion of the peripheral wall portion 46A on the vibration plate 24 side, and a short cylindrical tubular wall portion 46C extending from a radially outer end portion of the protruding wall portion 46B to the protector 18 side. The protruding wall portion 46B and the tubular wall portion 46C form a protruding portion 48 of the case 42 of the second embodiment. The protruding portion 48 is a portion of the case 42 that protrudes radially outward.

[0051] An end portion of the cylindrical wall portion 46C of the second component member 46 on the opposite side to the protruding wall portion 46B side (the upper side in FIG. 3) constitutes an open end portion 42A on the one side (the side in the direction of the arrow Z) of the case 42. In the following, when describing the parts constituting the first component member 44 and the second component member 46, they will be described as parts of the case 42.

[0052] The protector 18 is attached to the open end 42A of the case 42. The coil 22 housed in the case 42 is arranged so that its axial direction is along the depth direction of the case 42. The diaphragm 24 is arranged on the one side (the side in the direction of the arrow Z) of the case 42. The attachment portion 24A provided on the outer peripheral end side of the diaphragm 24 is attached by being sandwiched between the case 42 and the protector 18 over the entire circumference. The attachment portion 24A provided on the outer peripheral end side of the diaphragm 24 may be attached to the case 42 in another attachment form. The diaphragm 24 is connected to the coil 22 and is capable of vibrating in the axial direction of the coil 22.

[0053] A mover 50 (schematically shown in the figure) is housed in the case 42. The mover 50 has a magnetic circuit section including a magnet, and as a magnetic circuit section, has the same function as the mover 26 (see FIG. 2) of the first embodiment. An outer circumferential surface 50A1 of a maximum diameter portion 50A, which is a part of an outer circumferential surface 50S of the mover 50, is disposed with a clearance G therebetween that limits the amount of air movement relative to an inner circumferential surface 42B of the case 42.

[0054] The movable element 50 is aligned with the terminal position of the vibration plate 24 side on the outer peripheral surface 50A1 of the maximum diameter portion 50A at the inner peripheral surface 42B of the case 42. The length of the air flow path direction (vertical length in FIG. 3) on the outer peripheral surface 50A1 of the maximum diameter portion 50A of the movable element 50 is set to be longer than the length of the air flow path direction on the outer peripheral surface 26A1 of the maximum diameter portion 26A of the movable element 26 of the first embodiment (see FIGS. 1 and 2 for both). That is, the length of the air flow path (part where the clearance G is formed) that limits the amount of air movement is set to be longer in the second embodiment than in the first embodiment. The movable element 50 is attached to the leaf spring 28 attached to the case 42, and is configured to vibrate along the vibration direction of the vibration plate 24 by passing electricity through the coil 22.

[0055] The large diameter annular portion 28A as the outer periphery of the leaf spring 28 is attached to a portion between the first component member 44 and the second component member 46 of the case 42. The small diameter annular portion 28C as the center portion of the leaf spring 28 is attached to a bottom center portion 50B1 (a portion of the portion of the mover 50 opposite the diaphragm 24 side) on the other side (opposite the direction of the arrow Z) of the mover 50. Note that the leaf spring 28 in this embodiment has a longer distance between the large diameter annular portion 28A and the small diameter annular portion 28C than the leaf spring 28 in the first embodiment (see FIG. 2), but for convenience, the same reference numerals as the leaf spring 28 in the first embodiment (see FIG. 2) are used. In addition, in this embodiment, the outer peripheral surface 50B2 of the bottom surface 50B of the movable member 50 is a tapered surface that slopes toward the other side (the opposite side to the direction of arrow Z) as it extends radially inward from the outer peripheral end, and is a connection surface that is connected to the bottom surface central portion 50B1 via a step 50C.

[0056] On the other hand, the protruding wall portion 46B of the case 42 protrudes from an end portion 42X on the diaphragm 24 side of a portion that can face the outer circumferential surface 50A1 of the maximum diameter portion 50A with a clearance G when the mover 50 vibrates in the case 42, and faces the outer circumferential portion 24B of the diaphragm 24. The protruding wall portion 46B of the case 42 has a through hole 42H formed therein, which penetrates in a direction along the vibration direction of the mover 50. That is, the through hole 42H is formed on the open end portion 42A side of the clearance G in the case 42.

[0057] (Action and effect) Next, the operation and effects of the second embodiment will be described.

[0058] According to the second embodiment, although the end portion on one side (the side in the direction of arrow Z) of the peripheral wall portion 46A of the case 42 does not function as a base for fixing the leaf spring 28, essentially the same action and effect as the first embodiment described above can be obtained, except for the points described below.

[0059] In the second embodiment, the length of the air flow path that limits the amount of air movement when the movable element 50 is vibrating (i.e., the length in the vertical direction in the figure of the part where the clearance G is formed) is not maintained, but the length of the air flow path that limits the amount of air movement (the part where the clearance G is formed) is set longer than in the first embodiment, and the viscous resistance of the air flowing in and out of the clearance G when the movable element 50 vibrates can be increased. This makes it possible to stably exert the vibration generating function.

[0060] In the second embodiment, the small diameter annular portion 28C in the center of the leaf spring 28 is attached to the bottom central portion 50B1 on the other side (opposite the direction of the arrow Z) of the mover 50, so that the span of the leaf spring 28 is longer than that of the configuration of the first embodiment, and soft suspension characteristics can be realized. In addition, the outer peripheral surface 50B2 of the bottom surface 50B of the mover 50 is a tapered surface that inclines toward the other side (opposite the direction of the arrow Z) as it approaches the radial inside, and is a connection surface that is connected to the bottom central portion 50B1 via a step 50C, so that the mover 50 can be prevented from contacting the connecting portion 28B of the leaf spring 28 when the mover 50 vibrates.

[0061] As a modified example of the second embodiment, for example, the length of the outer peripheral surface (50A1) of the maximum diameter portion (50A) of the movable member (50) in the vibration direction (the vertical direction in FIG. 3) may be shortened, so that the length of the air flow path (the portion where the clearance G is formed) that limits the amount of air movement when the movable member (50) is vibrating is maintained.

[0062] [Third embodiment] Fig. 4 shows a cross-sectional view of a portion of a multi-function vibration actuator 60 according to the third embodiment. As shown in Fig. 4, the multi-function vibration actuator 60 according to the third embodiment differs from the multi-function vibration actuator 10 according to the first embodiment in that it includes a mover 62 (schematically shown in the figure) instead of the mover 26 (see Fig. 2) of the first embodiment. Other configurations are substantially similar to those of the first embodiment. In the third embodiment, components substantially similar to those of the first embodiment are denoted by the same reference numerals and descriptions thereof will be omitted as appropriate.

[0063] The mover 62 is housed in the case 32. An outer peripheral surface 62A1 of a maximum diameter portion 62A, which is a part of an outer peripheral surface 62S of the mover 62, is disposed with a clearance G that limits the amount of air movement from an inner peripheral surface 32B of the case 32. The mover 62 includes a magnet, and vibrates along the vibration direction of the diaphragm 24 by passing electricity through the coil 22. A component 62X on the outer peripheral side of the mover 62 is formed of a member separate from a main body portion 62H of the mover 62, and is integrally joined to the main body portion 62H of the mover 62. In FIG. 4, for convenience, an example of a boundary between the main body portion 62H of the mover 62 and the component 62X on the outer peripheral side of the mover 62 is shown by a two-dot chain line.

[0064] A groove 62G extending in the circumferential direction is formed on the outer circumferential surface 62S of the mover 62 on the outer circumferential surface 62A1 side of the maximum diameter portion 62A. As an example, the groove 62G is formed over the entire circumference of the outer circumferential surface 62S of the mover 62. Also, as an example, a plurality of grooves 62G (for example, two grooves) are formed in parallel at intervals in the vibration direction of the mover 62 (the up-down direction in FIG. 4).

[0065] Other than the points described above, the configuration of the mover 62 is similar to that of the mover 26 (see FIG. 2) of the first embodiment.

[0066] According to the third embodiment described above, it is possible to obtain substantially the same actions and effects as those of the first embodiment. Hereinafter, actions and effects unique to the third embodiment that are not present in the first embodiment will be described.

[0067] In the third embodiment, when air moves in the vibration direction of the mover 62 (the vertical direction in FIG. 4) between the portion formed by the outer circumferential surface 62A1 of the maximum diameter portion 62A of the mover 62 and the recessed groove 62G and the inner circumferential surface 32B of the case 32, an expansion loss can be generated in the portion where the flow path cross-sectional area increases abruptly, and a contraction loss can be generated in the portion where the flow path cross-sectional area decreases abruptly. That is, when air moves as described above, a pressure loss can be generated, so that the viscous resistance of the moving air can be increased. This can improve the damping function when the mover 62 vibrates.

[0068] Furthermore, since the groove 62G is formed around the entire circumference of the outer peripheral surface 62A1 side of the maximum diameter portion 62A of the movable member 62, when air moves in the vibration direction of the movable member 62 between the portion formed by the outer peripheral surface 62A1 of the maximum diameter portion 62A of the movable member 62 and the groove 62G and the inner peripheral surface 32B of the case 32, a pressure loss can be generated around the entire circumference of the air flow path, and the viscous resistance of the moving air can be increased around the entire circumference of the air flow path.

[0069] In addition, since the grooves 62G are formed in multiple parallel spaces at intervals in the vibration direction of the movable member 62, when air moves in the vibration direction of the movable member 62 between the outer peripheral surface 62A1 of the maximum diameter portion 62A of the movable member 62 and the portion formed by the grooves 62G and the inner peripheral surface 32B of the case 32, a greater pressure loss can be generated, and the viscous resistance of the moving air can be further increased.

[0070] In the third embodiment, the component 62X on the outer periphery of the mover 62 is formed of a separate member from the main body 62H of the mover 62. This makes it easy to manufacture the component 62X on the outer periphery of the mover 62 with high precision. By replacing the component 62X on the outer periphery of the mover 62, the resonance frequency of vibration can be adjusted, and product variations can be provided. As a modified example of the third embodiment, a configuration in which the main body (62H) of the mover (62) and the component (62X) on the outer periphery of the mover (62) are integrally formed can also be adopted.

[0071] [Modifications of the embodiment] 1 to 4, the through holes 32H, 42H are formed in the protruding wall portions 34C, 46B of the protruding portions 38, 48, but as a modified example, a through hole may be formed in the protruding portion (38, 48) that extends in a radial direction of the case (32, 42) in a portion that rises from the tip end of the protruding wall portion (34C, 46B) in the protruding direction toward the protector (18), such as the portion corresponding to the second component member 36 in the first and third embodiments or the cylindrical wall portion 46C in the second embodiment. In this modified example, it is also possible to set the amount of radial outward protrusion of the protruding portion (38, 48) to be smaller than that in the first to third embodiments.

[0072] Furthermore, in the above first to third embodiments, the cases 32 and 42 are each made up of two members, but the case may be made up of one member, or three or more members.

[0073] 3, the outer peripheral surface of the bottom surface (50B) of the mover (50) may be, for example, a tapered surface that slopes toward the other side (opposite the direction of the arrow Z) from the outer peripheral end toward the radially inward direction and is directly connected to the bottom central portion (50B1) of the mover (50). As another variation of the second embodiment, the outer peripheral surface of the bottom surface (50B) of the mover (50) may be, for example, a connection surface that is perpendicular to the vibration direction of the mover (50) and is connected to the bottom central portion (50B1) of the mover (50) via a step (50C).

[0074] In addition, in the third embodiment shown in Figure 4, the groove 62G is formed around the entire outer surface 62S of the movable member 62, but as a modified example of the third embodiment, the groove may extend in an arc shape in the circumferential direction of the outer surface (62S) of the movable member (62).

[0075] In addition, in the third embodiment shown in Figure 4, two grooves 62G are formed in parallel with a gap in the vibration direction of the movable element 62, but as a modified example of the third embodiment, a configuration in which three or more grooves are formed in parallel with a gap in the vibration direction of the movable element (62) may be adopted, or a configuration in which only one groove is formed may be adopted.

[0076] Furthermore, the multi-function vibration actuators 10, 40, 60 of the first to third embodiments shown in Figures 1 to 4 have a so-called internal magnet type magnetic circuit, but as a modification of the above embodiments, the present invention may also be applied to a multi-function vibration actuator having a so-called external magnet type magnetic circuit in which a ring-shaped magnet that forms part of the mover is arranged on the outer periphery of the coil.

[0077] As a modification of the above embodiment, a small diameter annular portion (28C) serving as the central portion of a leaf spring (28) may be attached to the portion of the movable member (26, 50, 62) on the vibration plate (24) side and on the portion opposite the vibration plate (24), and large diameter annular portions (28A) serving as the outer periphery of the two leaf springs (28) may be attached to the case (32, 42).

[0078] In addition, in the above first to third embodiments, the outer peripheral surfaces 26A1, 50A1, 62A1 of the maximum diameter portions 26A, 50A, 62A of the movable members 26, 50, 62 are arranged with a clearance G that limits the amount of air movement relative to the inner peripheral surfaces 32B, 42B of the cases 32, 42. However, as a modified example, for example, a configuration may be adopted in which a small diameter inner peripheral surface is formed by protruding a portion of the inner peripheral surface of the case inward, and the outer peripheral surface of a portion of the movable member that is smaller in diameter than the maximum diameter portion is arranged with a clearance that limits the amount of air movement relative to the small diameter inner peripheral surface of the case. The portion of the outer peripheral surface of the movable member that is arranged with a clearance that limits the amount of air movement relative to the inner peripheral surface of the case does not necessarily have to be the outer peripheral surface of the maximum diameter portion of the movable member.

[0079] As a modification of the first and third embodiments, the diameter of the leaf spring 28 may be made larger than that of the first and third embodiments, and the outer periphery of the leaf spring may be attached to the portion of the second component (36) on the first component (34) side.

[0080] The first to third embodiments and the multiple modifications described above can be implemented in appropriate combinations.

[0081] While one example of the present invention has been described above, the present invention is not limited to the above, and it goes without saying that the present invention can be implemented in various modified forms without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0082] 10 Multi-function vibration actuator 22 Coil 24 Diaphragm 24B Outer periphery of diaphragm 26 Mover 26S Outer surface of the mover 28 Leaf Spring 28A Large diameter circular part of the leaf spring (outer periphery of the leaf spring) 28C Small diameter circular part of leaf spring (center part of leaf spring) 32 cases 32A open end 32B Case inner surface 32H through hole 38 Overhang 40 Multi-function vibration actuator 42 cases 42A open end 42B Case inner surface 42H through hole 48 Overhang 50 mover 50B Bottom surface of the mover 50B1 Bottom center part 50B2 Outer circumferential surface of the bottom 50C step 50S Outer surface of the mover 60 Multi-function vibration actuator 62 Mover 62G concave groove 62S Outer surface of the mover 62H Main body of the mover 62X Outer circumferential component of the mover G Clearance Z One side

Claims

1. a case having an open end on one side; A coil housed in the case and arranged such that its axial direction is aligned with a depth direction of the case; a diaphragm disposed on the one side of the case, connected to the coil, and capable of vibrating in an axial direction of the coil; a movable element that is housed in the case, has an outer peripheral surface disposed with a clearance that limits the amount of air movement relative to an inner peripheral surface of the case, includes a magnet, and vibrates in the vibration direction of the diaphragm when current is applied to the coil; a leaf spring attached to the case and to which the movable element is attached; having the case includes a protruding portion that protrudes radially outward including the open end on the one side and faces an outer periphery of the diaphragm, A through hole is formed in the protruding portion, A multi-function vibration actuator, wherein the through hole is formed on the case closer to the open end than the clearance.

2. 2. The multifunction vibration actuator according to claim 1, wherein an outer periphery of the leaf spring is attached to the case, and a center portion of the leaf spring is attached to the movable element on the side opposite to the vibration plate.

3. The multifunction vibration actuator according to claim 1 , wherein the through hole penetrates the protruding portion in a radial direction of the case.

4. a center portion of the leaf spring is attached to a center portion of a bottom surface of the other side of the mover, 3. A multi-function vibration actuator as described in claim 2, wherein the outer peripheral surface of the bottom surface of the movable member is at least one of a tapered surface that slopes toward the other side as it approaches radially inward, and a connection surface that is connected to the center of the bottom surface via a step.

5. 2. The multifunction vibration actuator according to claim 1, wherein a groove is formed on an outer circumferential surface of said mover, said groove extending in a circumferential direction.

6. 6. The multifunction vibration actuator according to claim 5, wherein the groove is formed over the entire outer circumferential surface of the mover.

7. 6. The multifunction vibration actuator according to claim 5, wherein a plurality of said grooves are formed in parallel at intervals in the vibration direction of said mover.

8. 2. The multifunction vibration actuator according to claim 1, wherein a component portion on an outer periphery of the mover is formed of a separate member from a main body portion of the mover.

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