Large-displacement piezoelectric ceramic vibration structure

Abstract

According to the large-displacement piezoelectric ceramic vibration structure provided by the invention, the piezoelectric ceramic is not easy to damage, and the product reliability is good. The structure comprises an amplification mechanism, a piezoelectric ceramic body and a substrate, the amplification mechanism comprises an end cover and a middle protrusion of the end cover, the periphery of the end cover is connected with the periphery of the substrate, the piezoelectric ceramic body is fixed on the substrate, the substrate can deform along with transverse deformation of the piezoelectric ceramic body and drive the end cover to deform longitudinally, or the piezoelectric ceramic body is fixed on the substrate. The substrate can deform along with longitudinal deformation of the end cover and drive the piezoelectric ceramic body to deform transversely.

Description

Technical Field

[0001] The present invention relates to the technical field of piezoelectric ceramics, and particularly to a large-displacement piezoelectric ceramic vibration structure. Background Art

[0002] In recent years, piezoelectric ceramic transducers have been widely used in the fields of precision drive, ultrasonic machining, impact sensing, etc. due to their high precision and fast response characteristics. Among them, the cymbal-shaped piezoelectric transducer can convert the tiny longitudinal displacement of the piezoelectric ceramic into a larger vertical displacement through the lever amplification effect of the metal end cap, showing significant advantages in scenarios such as micropositioning and vibration energy harvesting.

[0003] The traditional single-layer piezoelectric ceramic cymbal structure has problems such as low mechanical strength and insufficient impact resistance. For example, the patent application with the publication number CN118877834A discloses a MEMS sensor based on a cymbal structure. Its cymbal structure includes a lower end cap layer, a lower electrode layer, a piezoelectric layer, an upper electrode layer, and an upper end cap layer. By applying a voltage to the upper and lower electrode layers, the piezoelectric layer generates a lateral displacement, which drives the upper and lower end cap layers to displace longitudinally, and thus the vibration of the structure can be realized. Also, the longitudinal displacement of the upper and lower end cap layers caused by vibration can make the piezoelectric layer undergo a lateral displacement and generate an induced voltage through the electrode layer. Since the components frequently displace and vibrate during the working process, the existing structure is likely to cause damage to the piezoelectric ceramic serving as the piezoelectric layer, thereby affecting the normal use of the transducer. Summary of the Invention

[0004] Aiming at the problem that the piezoelectric ceramic of the existing piezoelectric ceramic vibration structure is easily damaged, which affects the normal use of the transducer, the present invention provides a large-displacement piezoelectric ceramic vibration structure, in which the piezoelectric ceramic is not easily damaged and the product has good reliability.

[0005] Its technical solution is as follows: A large-displacement piezoelectric ceramic vibration structure includes an amplification mechanism and a piezoelectric ceramic body. The amplification mechanism includes an end cap, and the middle of the end cap bulges. It is characterized in that it further includes a substrate. The periphery of the end cap is connected to the periphery of the substrate, and the piezoelectric ceramic body is fixed on the substrate. The substrate can deform along with the lateral deformation of the piezoelectric ceramic body and drive the end cap to deform longitudinally, or the substrate can deform along with the longitudinal deformation of the end cap and drive the piezoelectric ceramic body to deform laterally.

[0006] Further, the piezoelectric ceramic body includes an upper piezoelectric ceramic and a lower piezoelectric ceramic. The upper piezoelectric ceramic is fixed on the upper side of the substrate, and the lower piezoelectric ceramic is fixed on the lower side of the substrate. Applying a voltage to the upper piezoelectric ceramic and the lower piezoelectric ceramic can make the substrate deform in the same direction.

[0007] Further, the substrate includes a ceramic connection portion for connecting the piezoelectric ceramic body and an end - cap connection portion for connecting the end - cap. The thickness of the ceramic connection portion is less than that of the end - cap connection portion.

[0008] Furthermore, the substrate further includes a first transition section located between the ceramic connection portion and the end - cap connection portion, and through - holes are provided on the first transition section.

[0009] Further, a soft O - ring is provided between the substrate and the end - cap.

[0010] Further, the end - cap includes a substrate connection portion, a pressure - bearing portion, and a second transition section. The substrate connection portion is located on the outer periphery of the end - cap and is connected to the substrate. The pressure - bearing portion is located at the middle convex portion of the end - cap. The second transition section is used to connect the substrate connection portion and the pressure - bearing portion. The included angle between the second transition section and the substrate is 10 degrees - 45 degrees.

[0011] Furthermore, the included angle between the second transition section and the substrate is 10 degrees - 15 degrees.

[0012] Furthermore, a hollowed - out groove is provided on the second transition section.

[0013] Further, the end - cap includes an upper end - cap and a lower end - cap. The middle of the upper end - cap protrudes upward, and the middle of the lower end - cap protrudes downward. The peripheral part of the upper end - cap is connected to the peripheral part on the upper side of the substrate, and the peripheral part of the lower end - cap is connected to the peripheral part on the lower side of the substrate.

[0014] Further, the end - cap is only located on one side of the substrate. The piezoelectric ceramic body is connected to the same side of the substrate, and the other side of the substrate is used to connect other structural members.

[0015] Beneficial effects: By setting the substrate and connecting the end - cap to the substrate, compared with the existing structure where the end - cap is directly connected to the piezoelectric ceramic body, in this solution, the piezoelectric ceramic body does not directly bear the force, thus greatly increasing the product reliability.

[0016] In addition, by setting piezoelectric ceramics on both sides of the substrate and making them vibrate in the same phase, compared with using only one piezoelectric ceramic, this solution improves the output force and further enhances the product's anti - impact ability. At the same time, by making the substrate thicker at the connection with the end - cap and setting a soft O - ring at the connection, stress can be absorbed layer by layer, further protecting the piezoelectric ceramic body. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the first embodiment of the present invention;

[0018] Figure 2Schematic cross-sectional view of Embodiment 1 of the present invention;

[0019] Figure 3 Schematic diagram of the piezoelectric ceramic body and the distribution of its surface electrodes;

[0020] Figure 4 is Figure 2 Enlarged view at location A in

[0021] Figure 5 Schematic diagram of the end cap structure;

[0022] Figure 6 Schematic cross-sectional view of Embodiment 2. Detailed implementation manner

[0023] Embodiment 1: As shown in Figure 1 and Figure 2 A large-displacement piezoelectric ceramic vibration structure, which includes a piezoelectric ceramic body 1, an end cap 2 as an amplification mechanism, and a substrate 3. The middle part of the end cap 2 protrudes in a cymbal shape, and the periphery of the end cap 2 is connected to the periphery of the substrate 3. The piezoelectric ceramic body 1 is fixed on the substrate 3. The substrate 3 can deform with the lateral deformation of the piezoelectric ceramic body 1 and drive the longitudinal deformation of the end cap 2, or the substrate 3 can deform with the longitudinal deformation of the end cap 2 and drive the lateral deformation of the piezoelectric ceramic body 1.

[0024] Specifically, the end cap 2 requires materials with high elastic modulus and good fatigue strength. Titanium alloy is preferably selected, and metal materials such as stainless steel, nickel alloy, and aluminum alloy can also be selected. The substrate 3 can be made of stainless steel, or metal materials such as copper and nickel alloy. The end cap 2 and the substrate 3 can be connected by bonding. To further ensure stable connection, increase the impact resistance and pressure resistance of the product, bolt holes can be provided at the periphery of the substrate 3, and the substrate 3 and the end cap 2 can be connected by screws, or glue can be filled in the bolt holes, or the substrate 3 and the end cap 2 can be fixed by welding, friction welding, etc.; the piezoelectric ceramic body 1 can be made of PZT5H material, or other piezoelectric ceramic materials such as PZT4, PZT5A, and PZT8. It can be fixed on the substrate 3 by bonding. By applying a voltage to the piezoelectric ceramic body 1, the piezoelectric ceramic body 1 can be caused to contract and deform, thereby driving the periphery of the substrate 3 to contract inward, and then driving the end cap 2 to undergo longitudinal deformation. Conversely, when the end cap 2 undergoes longitudinal deformation, the piezoelectric ceramic body 1 can be caused to contract and deform through the substrate 3, and then an induced voltage can be output.

[0025] Preferably, in this embodiment, the piezoelectric ceramic body 1 includes an upper piezoelectric ceramic 1-1 and a lower piezoelectric ceramic 1-2. The upper piezoelectric ceramic 1-1 is fixed on the upper side of the substrate 3, and the lower piezoelectric ceramic 1-2 is fixed on the lower side of the substrate 3. Applying a voltage to the upper piezoelectric ceramic 1-1 and the lower piezoelectric ceramic 1-2 can cause the substrate 3 to deform in the same direction. Specifically, in combination withFigure 3 , the upper surface electrode 1-1-1 of the upper piezoelectric ceramic 1-1 and the lower surface electrode 2 1-2-2 of the lower piezoelectric ceramic 1-2 are in the same direction when polarized, and the lower surface electrode 1-1-2 of the upper piezoelectric ceramic 1-1 and the upper surface electrode 2 1-2-1 of the lower piezoelectric ceramic 1-2 are in the same direction when polarized. After being bonded to the substrate 3, the upper surface electrode 1-1-1 and the upper surface electrode 2 1-2-1 are in the same direction when the power is turned on, and the lower surface electrode 1-1-2 and the lower surface electrode 2 1-2-2 are in the other direction when the power is turned on; in this way, the vibration effect can be maximized. For example, the upper surface electrode 1-1-1 and the upper Positive electricity is passed through the surface electrode 1-2-1, and the lower surface electrode 1-1-2 and the lower surface electrode 2 1-2-2 are connected to the negative end of the power supply. At this time, the polarization direction of the upper piezoelectric ceramic 1-1 is the same as the power supply pressure direction, and the piezoelectric ceramic shrinks and deforms. Because it is bonded to the surface of the substrate 3, the contraction of the piezoelectric ceramic above the substrate 3 will cause the substrate 3 to deform downward, driving the surrounding areas to shrink inward; the lower piezoelectric ceramic 1-2 has a polarization direction opposite to the power supply pressure direction, and the piezoelectric ceramic expands outward. Because the ceramic is bonded to the lower part of the substrate 3, the expansion of the piezoelectric ceramic below the substrate 3 can cause the substrate to deform downward, and the effect of the upper piezoelectric ceramic 1-1 is superimposed, thereby increasing the displacement and acceleration performance. Of course, you can also choose to only stick a piezoelectric ceramic body 1 on one side of the substrate 3.

[0026] Combination Figure 4 The substrate 3 specifically includes a ceramic connection part 3-1 for connecting the piezoelectric ceramic body 1 and an end cover connection part 3-2 for connecting the end cover 2. The thickness of the ceramic connection part 3-1 is less than that of the end cover connection part 3-2. The substrate 3 adopts a non-uniform thickness structure. On the one hand, the thin thickness of the ceramic connection part 3-1 can increase the transmission of amplitude and acceleration; on the other hand, the thick thickness of the end cover connection part 3-2 can absorb part of the pressing force during the pressing or falling process, further protecting the piezoelectric ceramic body 1 and preventing it from being broken due to excessive impact force. In order to further improve the acceleration performance, the substrate 3 also includes a transition section 3-3 located between the ceramic connection part 3-1 and the end cover connection part 3-2. A through hole is provided on the transition section 3-3, and the transmission effect is increased by adopting a local hole digging process.

[0027] On the basis of the above, in order to further absorb stress and impact, a soft O-ring 4 is provided between the substrate 3 and the end cover 2. The O-ring 4 is preferably made of soft silicone material, and can also be directly encapsulated with soft glue. The vibration is absorbed by adding the O-ring 4. If the O-ring is not used and only the bonding method is used, it is very easy to cause the end cover 2 and the substrate 3 to separate, and the pressure resistance is relatively low. The presence of the O-ring 4 can increase the bonding area and at the same time partially unload the pressing pressure to the side of the O-ring 4. In particular, when the product is subjected to vibration impact, the vibration wave can be absorbed by the O-ring 4 with greater damping, which greatly improves the stability of the overall structure.

[0028] In addition, the end cap 2 includes an upper end cap and a lower end cap. The middle part of the upper end cap bulges upward, and the middle part of the lower end cap bulges downward. The periphery of the upper end cap is connected to the periphery of the upper side of the substrate, and the periphery of the lower end cap is connected to the periphery of the lower side of the substrate 3. To ensure the vibration transmission effect, in combination with Figure 5 , the end cap 2 includes a substrate connection portion 2-1, a pressure-bearing portion 2-2, and a second transition section 2-3. The substrate connection portion 2-1 is located on the outer periphery of the end cap 2 and is connected to the substrate 3. The pressure-bearing portion 2-2 is located at the middle bulge of the end cap 2 for connecting with the vibrating member or the supporting member (in order to increase the adhesiveness, the surface of the pressure-bearing portion 2-2 can be treated, including but not limited to sandblasting, grinding, laser micromachining, or embossing). The second transition section 2-3 is used to connect the substrate connection portion 2-1 and the pressure-bearing portion 2-2. The included angle a between the second transition section and the substrate (in combination with Figure 3 ) is preferably 10 degrees - 15 degrees. For the convenience of electrode lead-out methods such as FPC, this included angle can also be slightly increased to 10 degrees - 45 degrees. A hollow groove 2-4 is provided on the second transition section 2-3. The hollow groove 2-4, such as an annular or radial groove, will locally weaken the stiffness of the amplification mechanism (i.e., the end cap 2, specifically the second transition section 2-3 of the end cap 2), making the amplification mechanism more likely to undergo elastic deformation under the drive of the piezoelectric ceramic body 1, thereby amplifying the output displacement, similar to an increase in the flexibility of a spring, with greater deformation under the same force. At the same time, the hollow groove 2-4 can guide the stress concentration to the flexible area near the groove opening, avoiding the uniform dispersion of stress, thereby improving the local strain efficiency and further amplifying the displacement output. The number of the hollow grooves 2-4 is preferably 6 - 8, and can also be 4 - 10, which depends on the matching effect between the resonance frequency of the amplification mechanism and the resonance frequency of the substrate 3 / piezoelectric ceramic body 1. The hollow groove 2-4 can adopt a keyway shape, or can also adopt shapes such as circular, annular, rectangular, elliptical, grid-shaped, bionic groove, etc., or a combination of several shapes.

[0029] Embodiment 2, in combination with Figure 6 , different from Embodiment 1, the end cap 2 is only located on one side of the substrate 3. The piezoelectric ceramic body 1 is connected to the same side of the substrate 3, and a double-sided adhesive 5 is bonded to the other side of the substrate 3 for connecting other structural parts, which can significantly reduce the height of the overall structure and meet the usage requirements of customers.

[0030] The above is only the preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those familiar with the technology within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A large-displacement piezoelectric ceramic vibration structure, which comprises an amplification mechanism and a piezoelectric ceramic body. The amplification mechanism includes an end cover, and the middle part of the end cover is convex. It is characterized in that: It further includes a substrate, the periphery of the end cover is connected to the periphery of the substrate, the piezoelectric ceramic body is fixed on the substrate, the substrate can deform along with the lateral deformation of the piezoelectric ceramic body and drive the longitudinal deformation of the end cover, or the substrate can deform along with the longitudinal deformation of the end cover and drive the lateral deformation of the piezoelectric ceramic body.

2. The large-displacement piezoelectric ceramic vibration structure according to claim 1, characterized in that: The piezoelectric ceramic body includes an upper piezoelectric ceramic and a lower piezoelectric ceramic. The upper piezoelectric ceramic is fixed on the upper side of the substrate, and the lower piezoelectric ceramic is fixed on the lower side of the substrate. Applying voltage to the upper piezoelectric ceramic and the lower piezoelectric ceramic can cause the substrate to deform in the same direction.

3. The large-displacement piezoelectric ceramic vibration structure according to claim 1, wherein: The substrate includes a ceramic connection portion for connecting the piezoelectric ceramic body and an end cover connection portion for connecting the end cover. The thickness of the ceramic connection portion is less than the thickness of the end cover connection portion.

4. A large-displacement piezoelectric ceramic vibration structure according to claim 3, characterized in that: The substrate further includes a first transition section located between the ceramic connection portion and the end cover connection portion, and through holes are provided on the first transition section.

5. A large-displacement piezoelectric ceramic vibration structure according to claim 1, characterized in that: A soft O-ring is provided between the substrate and the end cover.

6. The large-displacement piezoelectric ceramic vibration structure according to claim 1, wherein: The end cover includes a substrate connection portion, a pressure-bearing portion and a second transition section. The substrate connection portion is located on the outer periphery of the end cover and is connected to the substrate. The pressure-bearing portion is located at the middle convex portion of the end cover. The second transition section is used to connect the substrate connection portion and the pressure-bearing portion. The included angle between the second transition section and the substrate is 10 degrees - 45 degrees.

7. A large-displacement piezoelectric ceramic vibration structure according to claim 6, characterized in that: The included angle between the second transition section and the substrate is 10 degrees - 15 degrees.

8. A large-displacement piezoelectric ceramic vibration structure according to claim 6, characterized in that: Hollow grooves are provided on the second transition section.

9. A large-displacement piezoelectric ceramic vibration structure according to any one of claims 1-8, characterized in that: The end cover includes an upper end cover and a lower end cover. The middle of the upper end cover protrudes upward, and the middle of the lower end cover protrudes downward. The periphery of the upper end cover is connected to the periphery of the upper side of the substrate, and the periphery of the lower end cover is connected to the periphery of the lower side of the substrate.

10. A large-displacement piezoelectric ceramic vibration structure according to any one of claims 1, 3-8, characterized in that: The end cover is only located on one side of the substrate. The piezoelectric ceramic body is connected to the same side of the substrate, and the other side of the substrate is used to connect other structural components.

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