Actuator

Abstract

The invention relates to an actuator which reduces stress related to a bonding part of a vibration plate and a supporting body. An actuator (10) is provided with a piezoelectric vibrating body (100) and a support body (ST1). The piezoelectric vibrating body includes a plate member (31) having a surface (F311) and a surface (F312) facing each other, and a piezoelectric element disposed on the surface (F312). The support body has an annular shape in plan view. The support body is provided with an inner peripheral surface and an outer peripheral surface, each of which has an annular shape in plan view, and surfaces (FST11, FST12) connecting the inner peripheral surface and the outer peripheral surface. One surface (FST11) of the support body is bonded to the plate member. The plate member is provided with a thin portion (31TN). The thin portion has a ring shape formed by a shape in which a surface (F311) is recessed toward a surface (F312), and has an inner peripheral end and an outer peripheral end. When viewed in the thickness direction of the plate member, the outer peripheral end of the thin portion overlaps the inner peripheral surface of the support body.

Description

Technical Field

[0001] The present invention relates to an actuator having a piezoelectric vibrator and a support for supporting the piezoelectric vibrator. Background Technology

[0002] Patent Document 1 describes a structure in which the outer edge of a vibrating plate equipped with a piezoelectric element is fixed to a housing. An adhesive is used to bond the vibrating plate to the housing.

[0003] Patent Document 1: Japanese Patent Application Publication No. 10-220357

[0004] However, in the structure of Patent Document 1, the stress generated when the vibrating plate vibrates is concentrated in the fixed part, which may cause damage between the vibrating plate and the fixed part. Summary of the Invention

[0005] Therefore, the object of the present invention is to reduce the stress generated between the vibrating plate and the fixing part.

[0006] An actuator according to one embodiment of the present invention includes a piezoelectric vibrator and a support. The piezoelectric vibrator includes a plate member having a first surface and a second surface facing each other, and a piezoelectric element disposed on the second surface. The support is ring-shaped when viewed from above. The support has an inner peripheral surface and an outer peripheral surface that are respectively ring-shaped when viewed from above, and an end surface connecting the inner peripheral surface and the outer peripheral surface. One end surface of the support is bonded to the plate member. The plate member has a thin-walled portion. The thin-walled portion is a ring shape formed by a shape indented from the first surface towards the second surface, and has an inner peripheral end and an outer peripheral end. When viewed along the thickness direction of the plate member, the outer peripheral end of the thin-walled portion overlaps with the inner peripheral surface of the support.

[0007] In this structure, the stress involved at the bonding location between the plate component and the support is distributed to the thin-walled portion. Therefore, the stress involved at the bonding location between the plate component and the support is reduced.

[0008] According to the present invention, the stress generated between the vibrating plate and the support can be reduced. Attached Figure Description

[0009] Figure 1 This is an exploded perspective view of the actuator according to the first embodiment.

[0010] Figure 2 This is an exploded perspective view of the actuator according to the first embodiment.

[0011] Figure 3 (A) is a cross-sectional view showing a portion of the actuator according to the first embodiment. Figure 3 (B) is Figure 3 A magnified view of (A).

[0012] Figure 4 (A) is a sectional view of the plate component. Figure 4 (B) is a partially enlarged sectional view of the plate component.

[0013] Figure 5 (A) is a diagram showing an example of the distribution of stress applied to the actuator according to the first embodiment. Figure 5 (B) is a diagram showing the distribution of stress caused by vibration applied to the actuator of the comparative example.

[0014] Figure 6 This is a cross-sectional view showing a portion of the actuator involved in the second embodiment.

[0015] Figure 7 This is a cross-sectional view showing a portion of the actuator according to the third embodiment.

[0016] Figure 8 This is a cross-sectional view showing a portion of the actuator according to the fourth embodiment.

[0017] Explanation of reference numerals in the attached drawings: 10, 10A, 10B, 10C…actuators; 21, 22…piezoelectric elements; 31, 32, 33…plate components; 31TN, 32TN…thin-walled portions; 40…adhesive; 100…piezoelectric vibrator; 210, 220…piezoelectric bodies; 211, 212, 221, 222…driving electrodes; COV…recess; F211, F212, F221, F222, F311, F312, F321… F322, FST11, FST12, FST21, FST22…faces; Fe21, Fe22, Fe31, Fe32, Fe33…outer edges; FeST1, FeST2…outer peripheral surfaces; FiST1, FiST2…inner peripheral surfaces; IEC…inner peripheral end; OEC…outer peripheral end; PAD…corner; Po, Po21, Po22, Po31, Po32, Po33…center; ST1, ST2…supports. Detailed Implementation

[0018] [First Implementation Method]

[0019] The actuator according to the first embodiment of the present invention will be described with reference to the accompanying drawings. Figure 1 , Figure 2 This is an exploded perspective view of the actuator according to the first embodiment. Figure 1 and Figure 2 These are images observed in opposite directions along the stacking direction. Figure 3 (A) is a cross-sectional view showing a portion of the actuator according to the first embodiment. Figure 3 (B) is Figure 3A magnified view of (A). Figure 3 (A) is a diagram showing the movement from the center of the actuator to an outer edge (support).

[0020] Furthermore, the black dots marking the points (e.g., the center) in each diagram represent geometric locations and do not need to be physically visually identifiable objects. Additionally, in the following description, the structural elements constituting the actuator 10 viewed along the stacking direction will be referred to as the top view of each structural element.

[0021] like Figure 1 , Figure 2 , Figure 3 (A) Figure 3 As shown in (B), the actuator 10 includes a piezoelectric vibrator 100 and a support ST1. The piezoelectric vibrator 100 includes a piezoelectric element 21, a piezoelectric element 22, a plate component 31, a plate component 32, and a plate component 33.

[0022] The piezoelectric element 21 includes a piezoelectric body 210, a driving electrode 211, and a driving electrode 212. The piezoelectric body 210 is a circular plate. The piezoelectric body 210 has a surface F211, a surface F212, and an outer edge Fe21.

[0023] Surfaces F211 and F212 are circular when viewed from above along orthogonal directions. Surfaces F211 and F212 are opposite to each other. The outer edge Fe21 is circular when viewed from above.

[0024] A driving electrode 211 is disposed on surface F211. The driving electrode 211 is circular when viewed from above. A driving electrode 212 is disposed on surface F212. The driving electrode 212 is circular when viewed from above. The driving electrodes 211 and 212 overlap when viewed from above.

[0025] The driving electrodes 211 and 212 are thin films, for example, thinner than the piezoelectric body 210. For example, the driving electrodes 211 and 212 are formed on surfaces F211 and F212 of the piezoelectric body 210 by vapor deposition, sputtering, or the like. The driving electrodes 211 and 212 are electrodes intended to apply a voltage to the piezoelectric body 210.

[0026] The piezoelectric element 22 has the same structure as the piezoelectric element 21. The piezoelectric element 22 includes a piezoelectric body 220, a driving electrode 221, and a driving electrode 222. The piezoelectric body 220 is a circular plate. The piezoelectric body 220 has a surface F221, a surface F222, and an outer edge Fe22.

[0027] Surfaces F221 and F222 are circular when viewed from above along orthogonal directions. Surfaces F221 and F222 are opposite to each other. The outer edge Fe22 is circular when viewed from above.

[0028] A driving electrode 221 is disposed on surface F221. The driving electrode 221 is circular when viewed from above. A driving electrode 222 is disposed on surface F222. The driving electrode 222 is circular when viewed from above. The driving electrodes 221 and 222 overlap when viewed from above.

[0029] The driving electrodes 221 and 222 are thin films, for example, thinner than the piezoelectric body 220. For example, the driving electrodes 221 and 222 are formed on surfaces F221 and F222 of the piezoelectric body 220 by vapor deposition, sputtering, or the like. The driving electrodes 221 and 222 are electrodes intended to apply a voltage to the piezoelectric body 220.

[0030] The plate component 31 is made of metal, for example. The plate component 31 is a circular plate. The plate component 31 has a surface F311, a surface F312, and an outer edge Fe31. Surfaces F311 and F312 are circular when viewed from above in orthogonal directions. Surfaces F311 and F312 are opposite to each other. The outer edge Fe31 is circular when viewed from above. Surface F311 corresponds to the "first surface" of the present invention, and surface F312 corresponds to the "second surface" of the present invention.

[0031] Plate component 32 has the same structure as plate component 31. Plate component 32 is made of metal, for example. Plate component 32 is a circular plate. Plate component 32 has a surface F321, a surface F322, and an outer edge Fe32. Surfaces F321 and F322 are circular when viewed from above along orthogonal directions. Surfaces F321 and F322 are opposite to each other. The outer edge Fe32 is circular when viewed from above.

[0032] Plate component 33 is made of metal and is a circular plate. Plate component 33 has an outer edge Fe33.

[0033] Piezoelectric element 21, piezoelectric element 22, plate component 31, plate component 32 and plate component 33 are stacked as follows to form piezoelectric vibrator 100.

[0034] The plate component 31 is disposed on the surface F211 of the piezoelectric element 21 and is bonded by an adhesive or the like. More specifically, the plate component 31 is disposed on the piezoelectric element 21 with its surface F312 and surface F211 adjacent to each other and face to face.

[0035] The plate component 33 is disposed on the surface F212 of the piezoelectric element 21 and is bonded by adhesive or the like.

[0036] The piezoelectric element 22 is disposed on the side of the plate member 33 opposite to the disposed surface of the piezoelectric element 21, and is bonded by an adhesive or the like. At this time, the surface F222 of the piezoelectric element 22 is adjacent to and face-to-face with the plate member 33.

[0037] The plate component 32 is disposed on the surface F221 of the piezoelectric element 22 and bonded by adhesive or the like. More specifically, the plate component 32 is disposed on the piezoelectric element 22 with its surfaces F322 and F221 adjacent to each other and face to face.

[0038] At this point, when viewed from above (when viewed along the stacking direction), the center Po31 of plate component 31, the center Po21 of piezoelectric element 21, the center Po33 of plate component 33, the center Po22 of piezoelectric element 22, and the center Po32 of plate component 32 overlap (align). Furthermore, this overlap (alignment) is within the allowable range of manufacturing errors, including assembly errors.

[0039] By stacking piezoelectric element 21, piezoelectric element 22, plate component 31, plate component 32 and plate portion 33 in this way, the piezoelectric vibrator 100 achieves a dual piezoelectric wafer structure.

[0040] The support body ST1 is made of a material with high rigidity, such as metal. When viewed from above, the support body ST1 is annular in shape. The support body ST1 has an inner circumferential surface FiST1 and an outer circumferential surface FeST1, both of which are circular when viewed from above. The inner circumferential surface FiST1 is the inner surface of the annulus, and the outer circumferential surface FeST1 is the outer surface of the annulus.

[0041] The support body ST1 has a surface FST11 formed by an annular plane at one end in the thickness direction. The support body ST1 has a surface FST12 formed by an annular plane at the other end in the thickness direction. Surfaces FST11 and FST12 are connected to the inner peripheral surface FiST1 and the outer peripheral surface FeST1. FST11 and FST12 correspond to the end faces of the support body ST1.

[0042] The piezoelectric vibrator 100 is fixed and supported by the support ST1. More specifically, the surface FST12 of the support ST1 is bonded to the surface F311 of the plate member 31 in the piezoelectric vibrator 100. At this time, when viewed along the direction in which the piezoelectric vibrator 100 and the support ST1 are arranged, the center Po31 of the plate member 31 coincides with the center of the circle formed by the inner peripheral surface FiST1 of the support ST1.

[0043] In this structure, a first driving signal of a predetermined frequency is supplied to driving electrodes 211 and 212, and a second driving signal of a predetermined frequency is supplied to driving electrodes 221 and 222. The first and second driving signals have the same frequency. The frequencies of the first and second driving signals are set based on the resonant frequency of the piezoelectric vibrator 100, for example, approximately the same as the resonant frequency of the piezoelectric vibrator 100.

[0044] In this way, if a first drive signal and a second drive signal are supplied, the piezoelectric elements 21 and 22 undergo contraction deformation. The plate components 31 and 32 then bend and vibrate due to this contraction deformation. That is, the plate components 31 and 32 functionally become vibrating plates. The piezoelectric vibrator 100 generates bending vibration in a region that is more inward than the portion bonded and fixed to the support ST1. The bending vibration is a vibration that displaces in a direction parallel to the lamination direction, and the maximum displacement point of this bending vibration approximately coincides with the center Po of the region of the piezoelectric vibrator 100 not fixed to the support ST1 (the region that is more inward than the inner circumferential surface FiST1 of the support ST1 when viewed from above).

[0045] In such an actuator 10, the plate component 31 also has the following structure. Figure 4 (A) is a sectional view of the plate component. Figure 4 (B) is a partially enlarged sectional view of the plate component. Figure 4 (A) is a cross-sectional view obtained by cutting through the center of the plate component.

[0046] like Figure 4 (A) Figure 4 As shown in (B), plate member 31 has a recess COV. The recess COV is a shape recessed from surface F311. The recess COV is annular in shape, and when viewed in a direction orthogonal to surface F311, the recess COV has a circular outer peripheral end OEC and an inner peripheral end IEC.

[0047] The cross-sectional shape obtained by cutting the concave COV with a plane orthogonal to the direction of the annular shape is approximately semi-circular. In other words, the concave COV has no corners except for the ends that connect to the outer peripheral end OEC and the inner peripheral end IEC.

[0048] Furthermore, the shape of the concave COV is not limited to this; the cross-sectional shape obtained by cutting with a plane orthogonal to the direction of the toroidal shape can also be a rectangle with rounded corners. Additionally, the cross-sectional shape obtained by cutting with a plane orthogonal to the direction of the toroidal shape can also be a rectangle with corners.

[0049] The recessed COV has a depth DCOV. This depth DCOV corresponds to the deepest point of the recessed COV.

[0050] The plate component 31 has a thin-walled portion 31TN by having such a recess COV.

[0051] When viewed along a direction orthogonal to surfaces F311 and F312, the thin-walled portion 31TN overlaps with the area where the recessed portion COV is formed. The portion of surface F312 corresponding to the thin-walled portion 31TN is coplanar with the other portions of surface F312. Coplanarity means that they are in the same position in the thickness direction of the plate member 31. Furthermore, the portion of surface F311 corresponding to the thin-walled portion 31TN is shorter in distance from surface F312 compared to the other portions of surface F311.

[0052] With the recessed COV having the structure described above, the thin-walled portion 31TN has a curved shape that is recessed towards the surface F312 when viewed from the side of the plate member 31. Because the thin-walled portion 31TN does not have corners, it is possible to suppress breakage of the plate member 31 under applied stress, as will be described later. Furthermore, the shape of the thin-walled portion 31TN corresponds to the type of shape of the recessed COV described above, and can be of various shapes.

[0053] like Figure 3 (A) Figure 3 As shown in (B), the piezoelectric vibrator 100 of the plate component 31 having such a shape is bonded to the support ST1.

[0054] When viewed along the direction in which the piezoelectric vibrator 100 and the support ST1 are arranged, the outer peripheral end OEC of the recess COV of the plate member 31 overlaps with the inner peripheral surface FiST1 of the support ST1. More specifically, the outer peripheral end OEC of the recess COV of the plate member 31 overlaps with the inner peripheral surface FiST1 of the support ST1 in a circular pattern over the entire circumference. Furthermore, the term "overlap" as used herein includes the possibility of manufacturing errors. For example, the overlap of the outer peripheral end OEC of the recess COV with the inner peripheral surface FiST1 of the support ST1 is preferably such that the outer peripheral end OEC coincides with the inner peripheral surface FiST1.

[0055] However, the outer peripheral end OEC may deviate from the inner peripheral surface FiST1 towards the outer peripheral surface FeST1 within a specified range, or the outer peripheral end OEC may deviate from the inner peripheral surface FiST1 towards the center of the piezoelectric vibrator 100 within a specified range. In this case, if it deviates towards the outer peripheral surface FeST1, the specified range of deviation is such that the reduction in the bonding strength between the piezoelectric vibrator 100 and the support ST1 ensures the reliability required by the actuator 10. On the other hand, if it deviates towards the center of the piezoelectric vibrator 100, the specified range of deviation is such that the location of the maximum stress described later does not involve the corner PAD (the inner end of the surface where the plate member 31 is bonded to the support ST1).

[0056] However, preferably, when viewed along the direction in which the piezoelectric vibrator 100 and the support ST1 are arranged, the outer peripheral end OEC of the recess COV of the plate member 31 is not positioned outside the inner peripheral surface FiST1 of the support ST1. That is, preferably, when viewed along the direction in which the piezoelectric vibrator 100 and the support ST1 are arranged, the outer peripheral end OEC of the recess COV is not positioned between the inner peripheral surface FiST1 and the outer peripheral surface FeST1 of the support ST1.

[0057] According to this structure, a recess COV is formed on the side of the piezoelectric vibrator 100 that is bonded to the support ST1 (surface F311 of the plate member 31) along the inner peripheral surface FiST1 of the support ST1.

[0058] Alternatively, the thin-walled portion 31TN of the piezoelectric vibrator 100 is arranged along the inner peripheral surface FiST1 of the support ST1. Furthermore, the side of the thin-walled portion 31TN that is bonded to the support ST1 is located on the center side in the thickness direction of the piezoelectric vibrator 100 compared to the other portions, and is bonded to the piezoelectric element 21 with the surface.

[0059] In the actuator 10 with such a structure, stress is applied to the adhesive portion between the piezoelectric vibrator 100 and the support ST1 when the piezoelectric vibrator 100 vibrates.

[0060] Figure 5 (A) is a diagram showing an example of the distribution of stress applied to the actuator according to the first embodiment. Figure 5 (B) is a diagram showing an example of the distribution of stress caused by vibration applied to the actuator of the comparative example. Furthermore, the comparative example, compared to the actuator 10 according to this embodiment, does not have the recessed COV (thin-walled portion 31TN). Figure 5 (A) Figure 5 In (B), the darker the shading, the greater the applied stress.

[0061] First, such as Figure 5 As shown in (B), in the comparative example, the stress caused by the bending vibration of the piezoelectric vibrator 100 includes the inner corner PAD of the surface where the plate member 31 is bonded to the support ST1 and extends towards the plate member 31. Moreover, the location of the maximum stress is the corner PAD and its vicinity. This location is the end of the surface where the plate member 31 is bonded to the support ST1, and is a location where the bonded surface between the plate member 31 and the support ST1 is prone to breakage due to stress.

[0062] On the other hand, such as Figure 5As shown in (A), in the actuator 10, the portion with the maximum stress is the thin-walled portion 31TN due to the presence of the recessed portion COV (thin-walled portion 31TN). Furthermore, the stress at the corner PAD where the plate member 31 is bonded to the support ST1 is lower. This can be attributed to the fact that the thin-walled portion 31TN has lower rigidity compared to other parts of the plate member 31, making it easier to apply stress.

[0063] In this way, the actuator 10 can reduce the stress caused by vibration at the bonding surface between the plate component 31 and the support ST1, which is prone to breakage. Therefore, the actuator 10 can reduce the stress involved in the bonding area between the piezoelectric vibrator 100 and the support ST1. As a result, the actuator 10 can improve reliability.

[0064] At this point, even though the plate member 31 has a recessed COV (thin-walled portion 31TN), the actuator 10 hardly attenuates the bending vibration of the piezoelectric vibrator 100. As a specific example, according to simulation results, the actuator 10 can reduce the stress applied to the diagonal PAD by about 80% compared to the comparative example, and can maintain the maximum displacement caused by bending vibration at about 98% (limiting the attenuation rate to about 2%).

[0065] In this way, the actuator 10 can reduce the stress involved in the bonding area between the piezoelectric vibrator 100 and the support ST1 to improve reliability and suppress the deterioration of vibration performance.

[0066] Furthermore, it is preferable that the shapes of the aforementioned recessed COV and thin-walled portion 31TN satisfy, for example, the following conditions.

[0067] (A) The depth DCOV of the recessed COV is less than 2 / 3 of the thickness D31 of the plate member 31 (excluding the thickness of the portion forming the recessed COV). (Refer to) Figure 4 (B)). If expressed differently, the thickness of the thin-walled portion 31TN is more than 1 / 3 of the thickness of the plate component 31 (the thickness of the portion other than the thin-walled portion 31TN) D31.

[0068] (B) The width WCOV of the recessed COV (the width W31TN of the thin-walled portion 31TN) is less than or equal to the thickness D31 of the plate member 31 (the thickness of the portion other than the forming portion (thin-walled portion 31TN) of the recessed COV.

[0069] By satisfying at least one of these conditions, the actuator 10 can more reliably achieve the effects of improving reliability and suppressing the deterioration of vibration performance.

[0070] Furthermore, in the above description, the overlap between the outer peripheral end OEC of the recess COV of the plate member 31 and the inner peripheral surface FiST1 of the support ST1 indicates, for example, a manufacturing error. More specifically, when the distance from the center Po31 of the plate member 31 to the inner peripheral surface FiST1 of the support ST1 is set to 1, this error is preferably such that the distance (deviation) between the outer peripheral end OEC of the recess COV (thin-walled portion 31TN) and the inner peripheral surface FiST1 of the support ST1 is 9 / 100 or less.

[0071] As a result, the actuator 10 can more reliably achieve the effects of improving reliability and suppressing the deterioration of vibration performance.

[0072] [Second Implementation Method]

[0073] The actuator according to the second embodiment of the present invention will be described with reference to the accompanying drawings. Figure 6 This is a cross-sectional view showing a portion of the actuator involved in the second embodiment.

[0074] like Figure 6 As shown, the actuator 10A according to the second embodiment differs from the actuator 10 according to the first embodiment in that it includes the adhesive 40. The other structures of the actuator 10A are the same as those of the actuator 10, and descriptions of the same parts are omitted.

[0075] Actuator 10A includes adhesive 40. Adhesive 40 is made of a material with a lower elastic modulus compared to plate member 31. Adhesive 40 fills the recess COV. Alternatively, adhesive 40 may be configured to overlap with thin-walled portion 31TN.

[0076] According to this structure, actuator 10A, like actuator 10, is able to reduce the stress involved in the bonding area between piezoelectric vibrator 100 and support ST1.

[0077] Furthermore, the adhesive 40 can be formed by the adhesive between the bonding plate component 31 and the support ST1. Thus, when the bonding plate component 31 is bonded to the support ST1, the adhesive 40 flowing towards the inner circumferential surface FiST1 of the support ST1 fills the recess COV, achieving the aforementioned structure. Moreover, according to this structure, the flow of adhesive 40 towards the central side of the piezoelectric vibrator 100 beyond the recess COV can be suppressed, thereby preventing the deterioration of vibration characteristics.

[0078] [Third Implementation Method]

[0079] The actuator according to the third embodiment of the present invention will be described with reference to the accompanying drawings. Figure 7 This is a cross-sectional view showing a portion of the actuator according to the third embodiment.

[0080] like Figure 7 As shown, the actuator 10B according to the third embodiment differs from the actuator 10A according to the second embodiment in the area where the adhesive 40 is disposed. The other structures of the actuator 10B are the same as those of the actuator 10A, and descriptions of the same parts are omitted.

[0081] In actuator 10B, adhesive 40 fills the recess COV and protrudes from the surface F311 of plate member 31 toward the outside of the recess COV, and is configured to connect to the inner peripheral surface FiST1 of support ST1. In other words, adhesive 40 wets and diffuses from the recess COV onto the inner peripheral surface FiST1. At this time, adhesive 40 covers the corner PAD.

[0082] With this structure, actuator 10B, like actuator 10A, can reduce the stress involved in the bonding area between piezoelectric vibrator 100 and support ST1. Furthermore, in actuator 10B, the corner PADs are covered by adhesive 40, making it more difficult for the bonding surface between piezoelectric vibrator 100 and support ST1 to break.

[0083] [Fourth Implementation Method]

[0084] The actuator according to the fourth embodiment of the present invention will be described with reference to the accompanying drawings. Figure 8 This is a cross-sectional view showing a portion of the actuator according to the fourth embodiment.

[0085] like Figure 8 As shown, the actuator 10C according to the fourth embodiment differs from the actuator 10 according to the first embodiment in that it includes the support body ST2 and in the structure of the plate member 32. The other structures of the actuator 10C are the same as those of the actuator 10, and the description of the same parts is omitted.

[0086] Actuator 10C includes a support body ST2. Support body ST2 has the same structure as support body ST1. Support body ST2 has an inner circumferential surface FiST2 and an outer circumferential surface FeST2 that are circular when viewed from above. Support body ST2 has a surface FST21 formed by an annular plane at one end in the thickness direction. Support body ST2 has a surface FST22 formed by an annular plane at the other end in the thickness direction. Surfaces FST21 and FST22 are connected to the inner circumferential surface FiST2 and the outer circumferential surface FeST2.

[0087] The surface FST22 of the support ST2 is bonded to the surface F321 of the plate member 32 in the piezoelectric vibrator 100. At this time, when viewed along the direction in which the piezoelectric vibrator 100 and the support ST2 are arranged, the center Po32 of the plate member 32 coincides with the center of the circle formed by the inner peripheral surface FiST2 of the support ST2.

[0088] Furthermore, when viewed along the direction in which the support ST1, the piezoelectric vibrator 100, and the support ST2 are arranged, the support ST1 and the support ST2 overlap. At this time, the inner circumferential surface FiST1 of the support ST1 overlaps with the inner circumferential surface FiST2 of the support ST2.

[0089] The plate member 32 has a recess COV that is recessed from the surface F321. The plate member 32 has a thin-walled portion 32TN in the area overlapping with the recess COV.

[0090] When viewed along a direction orthogonal to the surfaces F311 of plate member 31 and F321 of plate member 32 in piezoelectric vibrator 100, the recess COV of plate member 31 overlaps with the recess COV of plate member 32. Alternatively, the thin-walled portion 31TN of plate member 31 overlaps with the thin-walled portion 32TN of plate member 32.

[0091] When viewed along the direction in which the piezoelectric vibrator 100 and the support ST2 are arranged, the outer peripheral end OEC of the recess COV of the plate component 32 overlaps with the inner peripheral surface FiST2 of the support ST2.

[0092] According to this structure, the actuator 10C can realize the structure of clamping the piezoelectric vibrator 100 by the support ST1 and the support ST2, and can reduce the stress involved in the bonding part between the piezoelectric vibrator 100 and the support ST1 and the bonding part between the piezoelectric vibrator 100 and the support ST2.

[0093] Furthermore, the structure of the fourth embodiment can be combined with the structures of the second and third embodiments.

[0094] Furthermore, in the embodiments described above, a method using a piezoelectric element without polarization reversal treatment is shown. However, it is also possible to use a piezoelectric element that has undergone polarization reversal treatment.

[0095] Furthermore, while the embodiments described above illustrate a piezoelectric vibrator constructed using two piezoelectric wafers, a piezoelectric vibrator constructed using a single piezoelectric wafer can also be used.

[0096] Furthermore, in the embodiments described above, the outer edges of the piezoelectric vibrator and the support are shown to be aligned when viewed from above. However, the outer edges of the piezoelectric vibrator and the support may not be aligned when viewed from above. Additionally, regarding the external shape of the piezoelectric element and the plate component, the external shape of the plate component may be the same as or larger than the external shape of the piezoelectric element. Furthermore, the external shapes of the plate component and the support are not limited to circular shapes.

Claims

1. An actuator, wherein, have: A piezoelectric vibrator includes a plate component having a first surface and a second surface that are opposite to each other, and a piezoelectric element disposed on the second surface; as well as The support structure, when viewed from above, is ring-shaped. The support body has an inner circumferential surface and an outer circumferential surface that are respectively ring-shaped when viewed from above, and an end face connecting the inner circumferential surface and the outer circumferential surface. One end face of the support is bonded to the plate component. The plate component has a thin-walled portion. The thin-walled portion is an annular shape formed by the first surface being recessed towards the second surface, and has an inner peripheral end and an outer peripheral end. When viewed along the thickness direction of the plate component, the outer peripheral end of the thin-walled portion overlaps with the inner peripheral surface of the support.

2. The actuator according to claim 1, wherein, It includes an adhesive that fills the recess formed by the shape of the depression.

3. The actuator according to claim 2, wherein, The adhesive protrudes from the first surface and is configured to attach to the inner circumferential surface.

4. The actuator according to claim 2, wherein, The elastic modulus of the adhesive is lower than that of the plate component.

5. The actuator according to any one of claims 1 to 4, wherein, When viewed from the side, the portion of the plate component corresponding to the thin-walled portion on the first surface has a curved shape that is recessed toward the second surface.

6. The actuator according to any one of claims 1 to 5, wherein, The thickness of the thin-walled portion is more than one-third of the thickness of the portion of the plate component excluding the thin-walled portion and less than the thickness of the portion of the plate component excluding the thin-walled portion.

7. The actuator according to any one of claims 1 to 6, wherein, The distance between the inner peripheral end and the outer peripheral end of the thin-walled portion is less than or equal to the thickness of the portion of the plate component other than the thin-walled portion.

Images