Actuator
By combining a piezoelectric vibrator, a leaf spring, and a support structure, and by synchronizing the buckling vibration of the leaf spring with the piezoelectric vibrator, the problem of limited displacement in existing actuators is solved, and a vibration effect with greater displacement is achieved.
Patent Information
- Application Number
- CN202511623954.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-11-11
- Filing Date
- 2025-11-07
- Publication Date
- 2026-05-12
AI Technical Summary
In existing actuators, the vibration displacement is limited due to the air resonance in the cavity formed by the vibrating substrate and the diaphragm, making it difficult to achieve vibration with a large displacement.
The structure employs a combination of a piezoelectric vibrator, a leaf spring, and a support. The leaf spring consists of a first and a second ring-shaped region. The design of the second region allows it to vibrate synchronously with the piezoelectric vibrator. The displacement of the leaf spring is greater than that of the piezoelectric vibrator, and the displacement is further increased by adjusting the natural vibration frequency and material properties.
It achieves vibration with a larger displacement than traditional structures. By using the buckling vibration of the leaf spring and the synchronous vibration of the piezoelectric vibrator, the displacement of the actuator is increased, meeting the large displacement requirements at specific frequencies.
Smart Images
Figure CN122028642A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to an actuator having a piezoelectric vibrator, the piezoelectric vibrator comprising a piezoelectric element and a plate component. Background Technology
[0002] Patent Document 1 describes a structure comprising a piezoelectric element, a vibrating substrate, and a diaphragm. The vibrating substrate is disposed on the piezoelectric element. The vibrating substrate has a recess. The diaphragm is disposed at a position covering the recess of the vibrating substrate.
[0003] Patent Document 1: Chinese Utility Model Announcement No. 208380823 Specification
[0004] In the structure of Patent Document 1, the vibration is caused by the air resonance in the cavity formed by the vibrating substrate and the diaphragm, so the displacement of the vibration is limited. Summary of the Invention
[0005] Therefore, the objective of this invention is to provide an actuator capable of producing vibrations with large displacement.
[0006] An actuator according to one embodiment of the present invention includes a piezoelectric vibrator, a leaf spring, and a support body. The piezoelectric vibrator is composed of a laminate of a plate component and a piezoelectric element, and has a first surface and a second surface facing each other. The leaf spring has a third surface connected to the first surface and a fourth surface facing the third surface. The support body is composed of a ring shape having an end face and a peripheral face.
[0007] The leaf spring has a first region in the shape of a ring and a second region surrounded by the first region. The first region has a third region on the outer edge side of the leaf spring and a fourth region on the second region side. In the third region, the leaf spring is connected to the support body and the piezoelectric vibrator while being sandwiched between the end face of the support body and the first face of the piezoelectric vibrator. In the fourth region, the leaf spring is connected to the piezoelectric vibrator but not to the support body. In the second region, the leaf spring is not connected to the piezoelectric vibrator.
[0008] In this structure, the leaf spring vibrates synchronously with the piezoelectric vibrator. At this time, the displacement of the leaf spring is greater than the displacement of the piezoelectric vibrator.
[0009] According to the invention, an actuator can be provided that can produce vibrations with large displacement. Attached Figure Description
[0010] Figure 1 This is an exploded perspective view of the actuator according to the first embodiment of the present invention.
[0011] Figure 2 This is an exploded perspective view of the actuator according to the first embodiment of the present invention.
[0012] Figure 3(A) Figure 3 (B) is a partial cross-sectional view of the actuator according to the first embodiment of the present invention.
[0013] Figure 4 (A) is a top view of the leaf spring according to the first embodiment of the present invention. Figure 4 (B) is a perspective view of the side view of the leaf spring. Figure 4 (C) is a cross-sectional view of the leaf spring. Figure 4 (D) is an enlarged cross-sectional view of the buckling section.
[0014] Figure 5 This is a partial cross-sectional view showing an example of the vibration state of the actuator according to the first embodiment of the present invention.
[0015] Figure 6 This is a partial cross-sectional view of the actuator according to the second embodiment of the present invention.
[0016] Figure 7 (A) Figure 7 (B) is a diagram representing a derived shape of a leaf spring.
[0017] Figure 8 (A) is a top view showing the derived shape of the leaf spring. Figure 8 (B) is its partial sectional view. 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 figures. Figure 1 , Figure 2 This is an exploded perspective view of the actuator according to the first embodiment of the present invention. Figure 1 and Figure 2 These are diagrams viewed from opposite directions in the stacking direction. Figure 3 (A) Figure 3 (B) is a partial cross-sectional view of the actuator according to the first embodiment of the present invention. Figure 3 (A) Figure 3 (B) is a diagram showing the outer edge (support body) side of the actuator from the center Po when viewed from above.
[0020] Furthermore, the black circles marking the points (e.g., center points) in each diagram indicate geometric locations and do not need to be physically visually identifiable objects. Additionally, in the following description, the various constituent elements of the actuator 10 viewed in the stacking direction will be referred to as top views 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, a leaf spring 40, and a support ST.
[0022] The piezoelectric vibrator 100 is composed of a stack of piezoelectric elements 21 and 22, plate components 31, 32, and 33. The piezoelectric vibrator 100 has two opposing surfaces, F101 and F102. Surface F101 corresponds to the "first surface", and surface F102 corresponds to the "second surface".
[0023] Piezoelectric element 21 and piezoelectric element 22 each include a piezoelectric body in the shape of a flat plate and a driving electrode formed on the opposing flat plate surface of the piezoelectric body.
[0024] Plate components 31, 32, and 33 are made of flat metal. The thicknesses of plate components 31, 32, and 33 are constant.
[0025] In the piezoelectric vibrator 100, the plate component 32, piezoelectric element 22, plate component 33, piezoelectric element 21, and plate component 31 are stacked in the order from surface F102 to surface F101. Thus, the piezoelectric vibrator 100 has a double piezoelectric crystal structure.
[0026] The surface of plate component 31 opposite to the side opposite to piezoelectric element 21 becomes surface F101 of piezoelectric vibrator 100. The surface of plate component 32 opposite to the side opposite to piezoelectric element 22 becomes surface F102 of piezoelectric vibrator 100.
[0027] Figure 4 (A) is a top view of the leaf spring according to the first embodiment of the present invention. Figure 4 (B) is a perspective view of the side view of the leaf spring. Figure 4 (C) is a cross-sectional view of the leaf spring. Figure 4 (D) is an enlarged cross-sectional view of the buckling section. Figure 4 (C) represents Figure 4 AA section in (A).
[0028] like Figure 4 (A) Figure 4 (B) Figure 4 As shown in (C), the leaf spring 40 has two opposing surfaces, F401 and F402. Surface F401 corresponds to the "fourth surface", and surface F402 corresponds to the "third surface".
[0029] The leaf spring 40 is made of, for example, a metal plate. The thickness of the leaf spring 40 is generally constant. The leaf spring 40 is made of a material that is more prone to buckling vibration than the piezoelectric vibrator 100.
[0030] The leaf spring 40 has a first region 41 and a second region 42. In top view, the first region 41 is annular and includes the outer edge Fe40 of the leaf spring 40. In top view, the second region 42 includes the center Po40 of the circular leaf spring 40, which is surrounded by the first region 41.
[0031] The first region 41 has a third region 411 and a fourth region 412. The third region 411 is an annular shape centered at a point Po40 when viewed from above, and includes an outer edge Fe40. The fourth region 412 is an annular shape centered at a point Po40 when viewed from above, and is connected to the inner peripheral end of the third region 411. The first region 41, which extends to the third region 411 and the fourth region 412, has a flat shape.
[0032] The second region 42 has a fifth region 421 and a sixth region 422. The fifth region 421 is a circle centered at point Po when viewed from above. The sixth region 422 is an annular shape centered at point Po when viewed from above. The inner periphery of the sixth region 422 is connected to the fifth region 421. The outer periphery of the sixth region 422 is connected to the inner periphery of the fourth region 412 of the first region 41.
[0033] The leaf spring 40 has a shape in which the second region 42 protrudes towards the surface F401 compared to the first region 41. More specifically, the second region 42 has surfaces F401 and F402 of the fifth region 421 parallel to surfaces F401 and F402 of the first region 41, and the sixth region 422 has a conical shape that is not inclined at 90° when viewed from the side.
[0034] use Figure 4 In other words, at the junction of the fourth region 412 and the sixth region 422, the buckling angle on the F402 side is greater than 90° and less than 180°. At the junction of the sixth region 422 and the fifth region 421, the buckling angle on the F402 side is greater than 180° and less than 270°. The fourth region 412, the sixth region 422, and the fifth region 421 are connected in a manner that satisfies these conditions.
[0035] like Figure 3 (A) Figure 3 As shown in (B), a leaf spring 40 with such a structure is disposed on the piezoelectric vibrator 100 with surface F402 adjacent to surface F101 of the piezoelectric vibrator 100. The outer edge Fe40 of the leaf spring 40 is disposed at a position approximately the same as the outer edge of the piezoelectric vibrator 100.
[0036] The surface F402 of the first region 41 of the leaf spring 40 engages with the surface F101 of the outer edge of the piezoelectric vibrator 100. Alternatively, this engagement can be adhesive. However, in the case of adhesive, it is preferable to use an adhesive with a high elastic modulus, in other words, to ensure that the stress involving the piezoelectric vibrator 100 is transmitted to the leaf spring 40 with minimal loss.
[0037] Since the leaf spring 40 has the above-described structure, the second region 42 of the leaf spring 40 is separated from the surface F101 of the piezoelectric vibrator 100.
[0038] At this point, when viewed from above (in the stacking direction), the center Po41 of the leaf spring 40 coincides with the center Po of the piezoelectric vibrator 100. Furthermore, this coincidence is within the range of manufacturing tolerances.
[0039] The support body ST is made of a highly rigid material such as metal. Viewed from above, the support body ST is annular in shape. Viewed from above, the support body ST has a circular inner circumferential surface FiST and an outer circumferential surface FeST. The inner circumferential surface FiST is the inner surface of the annular shape, and the outer circumferential surface FeST is the outer surface of the annular shape. At one end of the support body ST in the thickness direction, there is an end face FST1 composed of annular-shaped planes. At the other end of the support body ST in the thickness direction, there is an end face FST2 composed of annular-shaped planes.
[0040] The end face FST2 of the support ST is connected to the surface F401 of the third region 411 of the leaf spring 40. Furthermore, this connection is a physical connection, achieved through joining, bonding, or the like. However, in the case of bonding, it is preferable to use an adhesive with a high elastic modulus; in other words, the portion overlapping the support ST when viewed from above can be fixed so that the piezoelectric vibrator 100 and the leaf spring 40 do not vibrate substantially.
[0041] The fourth region 412 of the leaf spring 40 is not connected to the support ST.
[0042] Figure 5 This is a partial cross-sectional view showing an example of the vibration state of the actuator according to the first embodiment of the present invention. Figure 5 Indicates and Figure 3 (A) Figure 3 The same location as (B). In Figure 5 In the diagram, 100DFL represents the state where the displacement of the piezoelectric vibrator 100 is the minimum (0), and 100MX represents the state where the displacement of the piezoelectric vibrator 100 is the maximum. 40DFL represents the state where the displacement of the leaf spring 40 is the minimum (0), and 40MX represents the state where the displacement of the leaf spring 40 is the maximum.
[0043] In this structure, if a drive signal of a predetermined frequency is applied to the piezoelectric vibrator 100, the piezoelectric elements 21 and 22 of the piezoelectric vibrator 100 deform, and the stress generated by this deformation is applied to the plate components 31, 32, and 33. The outer edge REo100 of the piezoelectric vibrator 100 is fixed to the support ST via the third region 411 of the leaf spring 40. Thus, the piezoelectric vibrator 100 undergoes buckling vibration with the inner circumferential end of the outer edge REo100 (the end that overlaps with the inner circumferential surface FiST1 of the support ST in top view) as the fixed end. The maximum amplitude point of this buckling vibration is the center Po of the piezoelectric vibrator 100. Furthermore, in this structure, the frequency of the drive signal is approximately the same as the resonant frequency of the piezoelectric vibrator 100. Therefore, the piezoelectric vibrator 100 undergoes first-order resonant buckling vibration.
[0044] The leaf spring 40 is connected to the piezoelectric vibrator 100 in a fourth region 412 between the third region 411 (the fixing part to the support ST) and the second region 42. Therefore, the stress of deformation generated when the piezoelectric vibrator 100 vibrates is applied to the fourth region 412 of the leaf spring 40.
[0045] The stress applied to the fourth region 412 is applied to the second region 42 (the sixth region 422 and the fifth region 421). As a result, the leaf spring 40 undergoes buckling vibration. The buckling vibration of the leaf spring 40 is synchronized with the buckling vibration of the piezoelectric vibrator 100. Furthermore, the point of maximum amplitude of the buckling vibration of the leaf spring 40 is the center Po40 of the leaf spring 40.
[0046] As described above, the leaf spring 40 is more prone to buckling vibration than the piezoelectric vibrator 100. Therefore, the displacement generated by the vibration of the leaf spring 40 is greater than the displacement generated by the vibration of the piezoelectric vibrator 100. For example, as... Figure 5 As shown, the maximum displacement DSP40 of the center Po41 of the leaf spring 40 is greater than the maximum displacement DSP100 of the center Po of the piezoelectric vibrator 100, for example, about twice as much.
[0047] In this way, actuator 10 can generate vibrations with a larger displacement than if leaf spring 40 were not used.
[0048] Furthermore, in the actuator 10, by making the sixth region 422 of the second region 42 conical, the stress applied to the leaf spring 40 can be converted into buckling vibration more effectively. As a result, the actuator 10 is able to generate vibrations with a larger displacement.
[0049] Furthermore, in the actuator 10, the shape, material, weight, etc. of the leaf spring 40 are configured such that the natural vibration frequency F40 of the leaf spring 40 satisfies the following range relative to the resonant frequency F100 of the piezoelectric vibrator 100.
[0050] 0.3×F100<F40<0.7×F100
[0051] By satisfying this range, the leaf spring 40 vibrates more effectively through the vibration of the piezoelectric vibrator 100. As a result, the actuator 10 is able to effectively generate vibrations with a larger displacement.
[0052] Furthermore, the dimensions of each component in the preferred actuator 10 satisfy the following conditions (for example, referring to...). Figure 3 (B)
[0053] • The distance from the center of the leaf spring 40 (the overlapping position when viewed from above at the center Po of the piezoelectric vibrator 100) to the end where the second region 42 and the fourth region 412 connect ( Figure 3 The distance obtained by subtracting L412 from LVB in (B) is greater than the distance (length L412 of the fourth region 412) between the connection end of the fourth region 412 to the connection end to the third region 411.
[0054] • The distance LVB from the center Po of the piezoelectric vibrator 100 to the inner circumference of the outer edge REo100 and the length L422 of the sixth region 422 (the distance between the connection end to the fifth region 421 and the connection end to the fourth region 412) when viewed from above satisfy the following relationship.
[0055] (13 / 50)×LVB≤L422≤(21 / 50)×LVB
[0056] • The distance LVB from the center Po of the piezoelectric vibrator 100 to the inner circumference of the outer edge REo100 and the length L412 of the fourth region 412 (the distance between the connection end to the third region 411 and the connection end to the sixth region 422) when viewed from above satisfy the following relationship.
[0057] (1 / 25)×LVB≤L412≤(3 / 10)×LVB
[0058] By satisfying any one of these conditions, the actuator 10 can effectively generate vibrations with a large displacement.
[0059] [Second Implementation]
[0060] The actuator according to the second embodiment of the present invention will be described with reference to the figures. Figure 6 This is a partial cross-sectional view of the actuator according to the second embodiment of the present invention.
[0061] like Figure 6As shown, the actuator 10A according to the second embodiment differs from the actuator 10 according to the first embodiment in that it includes a piezoelectric vibrator 100A. The other structures of the actuator 10A are the same as those of the actuator 10, and descriptions of the same parts are omitted.
[0062] The actuator 10 includes a piezoelectric vibrator 100A. The piezoelectric vibrator 100A includes piezoelectric elements 21A and 22A. The piezoelectric elements 21A and 22A undergo polarization reversal at a predetermined distance from the center of the piezoelectric body toward the outer edge.
[0063] When viewed in the direction in which the support ST, leaf spring 40, and piezoelectric vibrator 100 are arranged, the fourth region 412 of the leaf spring 40 is positioned differently from the polarization reversal position Ppr. More specifically, the fourth region 412 of the leaf spring 40 is positioned closer to the support ST than the polarization reversal position Ppr.
[0064] With this structure, actuator 10A is the same as actuator 10 and can generate vibrations with a large displacement.
[0065] Furthermore, preferably, when viewed from above, the distance from the center Po to the fourth region 412 is more than 1.2 times and less than 1.4 times the distance from the center Po to the polarization reversal position Ppr.
[0066] (Derived shapes of leaf springs)
[0067] Figure 7 (A) Figure 7 (B) is a diagram representing a derived shape of a leaf spring. Figure 7 (A) Figure 7 (B) is a cross-sectional view showing the outer edge (support body) side from the center Po40 of the leaf spring when viewed from above.
[0068] like Figure 7 As shown in (A), the leaf spring 40X1 has a second region 42X1. The second region 42X1 has a fifth region 421X1 and a sixth region 422X1.
[0069] The thickness D421X1 of the fifth region 421X1 is different from the thickness D41 of the first region 41 (the third region 411 and the fourth region 412), and is smaller than the thickness D41. This at least satisfies the requirement that the maximum thickness of the fifth region 421X1 is smaller than the minimum thickness of the first region 41.
[0070] The sixth region 422X1 has a thickness D41 at the connection end (one end) to the fourth region 412, and a thickness D421X1 at the connection end (the other end) to the fifth region 421X1. The thickness of the sixth region 422X1 gradually increases from one end to the other. Therefore, the sixth region 422X1 has a region with a smaller thickness than the thickness D41 of the first region 41. Consequently, the second region 42X1, formed by the fifth region 421X1 and the sixth region 422X1, has a region with a smaller thickness than the thickness D41 of the first region 41. Furthermore, the average thickness of the second region 42X1 is smaller than the thickness D41 of the first region 41 (the third region 411 and the fourth region 412).
[0071] Furthermore, the aforementioned thicknesses can be measured, for example, by observing the cross-section using an optical microscope or a micrometer. Moreover, by measuring the thickness at multiple points for each region and averaging the measured thicknesses, the average thickness of each region can be calculated.
[0072] This structure allows for a further increase in the maximum displacement of the 40X1 leaf spring.
[0073] like Figure 7 As shown in (B), the leaf spring 40X2 has a second region 42X2. The second region 42X2 has a fifth region 421X2 and a sixth region 422X2.
[0074] The thickness D421X2 of the fifth region 421X2 is different from the thickness D41 of the first region 41 (the third region 411 and the fourth region 412), and is larger than the thickness D41. This at least satisfies the requirement that the minimum thickness of the fifth region 421X2 is greater than the maximum thickness of the first region 41.
[0075] The sixth region 422X2 has a thickness D41 at the connection end (one end) to the fourth region 412 and a thickness D421X2 at the connection end (the other end) to the fifth region 421X2. The thickness of the sixth region 422X2 gradually increases from one end to the other. Therefore, the sixth region 422X2 has a region with a greater thickness than the thickness D41 of the first region 41. Consequently, the second region 42X2, formed by the fifth region 421X1 and the sixth region 422X1, has a region with a greater thickness than the thickness D41 of the first region 41. Furthermore, the average thickness of the second region 42X1 is greater than the thickness D41 of the first region 41 (the third region 411 and the fourth region 412).
[0076] This structure allows for a larger maximum displacement of the 40X1 leaf spring compared to a configuration without the 40X1 leaf spring.
[0077] Figure 8(A) is a top view showing the derived shape of the leaf spring. Figure 8 (B) is its partial sectional view.
[0078] like Figure 8 As shown in (A), the leaf spring 40X3 has a second region 42X3. The second region 42X3 has a fifth region 421 and a sixth region 422X3.
[0079] The thickness D421 of the fifth region 421 is the same as the thickness D41 of the first region 41 (the third region 411 and the fourth region 412). The thickness of the sixth region 422X3 is the same as the thickness D421 of the fifth region 421 and the thickness D41 of the first region 41.
[0080] Multiple through holes TH42 are formed in the sixth region 422X3. The multiple through holes TH42 are holes that penetrate the sixth region 422X3 from face F401 to face F402.
[0081] With this structure, compared to the case where the through hole TH42 is not formed, the mass and rigidity of the sixth region 422X3 are reduced, thus enabling a further increase in the maximum displacement of the leaf spring 40X3.
[0082] Furthermore, it is preferable that the multiple through holes TH42 are formed in a point-symmetric manner relative to the center Po42 when viewed from above.
[0083] Furthermore, the various derived shapes mentioned above can be appropriately combined.
[0084] In the embodiments described above, the leaf spring is indicated to be made of metal. However, the leaf spring is not limited to metal. For example, even with materials other than metal, as described above, as long as the natural vibration frequency of the leaf spring is approximately the same (more preferably identical) to the resonant frequency of the piezoelectric vibrator, the actuator can generate vibrations with a large displacement.
[0085] In the embodiments described above, the outer edge of the piezoelectric vibrator is indicated to be circular. However, the outer edge of the piezoelectric vibrator is not limited to a circular shape.
[0086] Explanation of reference numerals in the attached figures
[0087] 10, 10A...Actuator; 21, 21A...Piezoelectric element; 22, 22A...Piezoelectric element; 31, 32, 33...Plate component; 40, 40X1, 40X2, 40X3...Leaf spring; 41...First region; 42, 42X1, 42X2, 42X3...Second region; 100, 100A...Piezoelectric vibrator; 411...Third region; 412...Fourth region; 421, 421X1, 421X2...Fifth region; 422, 422X1, 422X2, 422X3...Sixth region; ST...Support; TH42...Through hole.
Claims
1. An actuator, wherein, have: A piezoelectric vibrator is composed of a laminate of plate components and piezoelectric elements, having a first surface and a second surface that are opposite to each other. A leaf spring having a third surface connected to the first surface and a fourth surface opposite to the third surface; and The support body is composed of a ring shape with end faces and circumferential faces. The aforementioned leaf spring has a first region in the shape of a ring, and a second region surrounded by the first region. The first region described above includes a third region on the outer edge side of the leaf spring and a fourth region on the second region side. The leaf spring is connected to the support body and the piezoelectric vibrator in the third region, where it is sandwiched between the end face of the support body and the first face of the piezoelectric vibrator. It is connected to the first surface of the piezoelectric vibrator in the fourth region, but not to the support body. It is not connected to the piezoelectric vibrator in the second region mentioned above.
2. The actuator according to claim 1, wherein, The average thickness of the second region in the aforementioned leaf spring is smaller than the thickness of the fourth region.
3. The actuator according to claim 2, wherein, The second region described above has a fifth region containing the center of the leaf spring, and a sixth region connecting the fifth region and the fourth region. The thickness of the fifth region is smaller than the average thickness of the sixth region.
4. The actuator according to any one of claims 1 to 3, wherein, The distance from the center of the leaf spring to the connection end to the fourth region in the second region is greater than the distance between the connection end of the fourth region to the second region and the connection end to the third region.
5. The actuator according to any one of claims 1 to 4, wherein, The second region of the aforementioned leaf spring has a thickness different from that of the first region, or has a through hole.
6. The actuator according to claim 5, wherein, The second region described above has a fifth region containing the center of the leaf spring, and a sixth region connecting the fifth region and the fourth region. The aforementioned through hole is located in the sixth region.
7. The actuator according to any one of claims 1 to 6, wherein, The piezoelectric element described above undergoes polarization reversal at a predetermined distance from its center toward its outer edge. When viewed in the direction in which the support, the leaf spring, and the piezoelectric vibrator are arranged, the fourth region is positioned closer to the support than the polarization reversal position.
8. The actuator according to any one of claims 1 to 7, wherein, The aforementioned leaf spring is made of metal.