A testing device and a testing method for a piezoelectric device

Abstract

The present application belongs to the technical field of piezoelectric ceramics, and provides a testing device and a testing method for a piezoelectric device, including a bearing assembly and a testing assembly, wherein the bearing assembly includes a first bearing plate, a second bearing plate and a bearing back plate, wherein the first bearing plate and the second bearing plate are connected to the bearing back plate at intervals along a first direction, and the testing assembly is located between the first bearing plate and the second bearing plate, and sequentially includes a first flexible support member, a second flexible support member, a top clamping plate and a force-applying structure, wherein the piezoelectric device is placed between the first flexible support member and the second flexible support member, wherein the first flexible support member and the second flexible support member are rigid in a first direction and flexible in a second direction and a third direction perpendicular to the first direction, thereby achieving decoupling of tangential stress and normal stress and improving the protective effect on the piezoelectric device, and wherein the force-applying structure applies prestress or bearing stress to the piezoelectric device, thereby preventing dynamic stress from damaging the piezoelectric device, and adapting to the testing of products of various specifications.

Description

Technical Field

[0001] The present application relates to the technical field of piezoelectric ceramics, and in particular to a testing device and a testing method for a piezoelectric device. Background Art

[0002] Piezoelectric materials have unique physical properties. When voltage is applied to them, piezoelectric materials will deform and produce displacement. When mechanical stress is applied to them, piezoelectric materials will generate electric charge. Piezoelectric stacks work based on this principle. Piezoelectric stacks are formed by stacking multiple layers of piezoelectric materials. Each layer is coated with electrodes. The displacement of its output is controlled by controlling the applied voltage. The unique piezoelectric properties give piezoelectric materials unique advantages in precision control and energy conversion. Piezoelectric stacks, such as piezoelectric ceramic stacks, are usually composed of crystal structures. When the piezoelectric stack is subjected to normal pressure, the crystal structure will be more compact, enhancing the strength of the material. When the piezoelectric stack is subjected to normal tension, the tension will expand the defects in the lattice structure, making the piezoelectric stack more likely to break. The lattice structure of the piezoelectric material also determines that it is difficult to withstand tangential stress.

[0003] In actual production, in order to ensure that the performance and life of the device meet the product specifications, the assembled piezoelectric stack needs to undergo reliability testing, and can only be installed in the matching device structure after passing the test. When conducting reliability testing on the piezoelectric stack, a bias AC voltage is applied to drive the piezoelectric stack to continuously expand and contract. During the continuous expansion and contraction process, the piezoelectric stack is very sensitive to stress. When subjected to tangential stress or torsional force, it is very easy to cause cracking and other damage. In addition, when the piezoelectric stack is tested in a free state, it is easily loaded with dynamic stress, which greatly increases the risk of damage to the piezoelectric stack.

[0004] Based on this, in order to solve the above problems, the present application provides a testing device and a testing method for a piezoelectric device to reduce the risk of damage to the piezoelectric stack during the testing process. Summary of the invention

[0005] In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a testing device and a testing method for a piezoelectric device, so as to solve the problems existing in the prior art such as the high risk of damage to the piezoelectric device during the testing process.

[0006] To achieve the above-mentioned object and other related objects, the present application provides a testing device for a piezoelectric device, comprising a bearing assembly and one or more testing assemblies spaced apart and distributed along a second direction;

[0007] The bearing assembly comprises a first bearing plate, a second bearing plate and a bearing back plate, the bearing back plate has a front side and a back side which are arranged opposite to each other, the second bearing plate is slidably connected to the front side of the bearing back plate and can move along a first direction, the first bearing plate is spaced below the second bearing plate along the first direction and is connected to the front side of the bearing back plate;

[0008] The test assembly is located between the first bearing plate and the second bearing plate, and includes a first flexible support member, a second flexible support member, a top clamping plate and a force-applying structure arranged in sequence along the first direction, the first flexible support member is located on the first bearing plate, the second flexible support member is coaxially arranged above the first flexible support member along the first direction, the piezoelectric device is placed between the first flexible support member and the second flexible support member, and the force-applying structure is connected to the second bearing plate for applying prestress or bearing stress to the piezoelectric device;

[0009] Among them, the first flexible support member and the second flexible support member are rigid in the first direction and flexible in the second direction and the third direction, the first direction and the second direction are both parallel to the front side of the supporting back plate, and the first direction, the second direction and the third direction are perpendicular to each other.

[0010] Optionally, at least two movable guide rails spaced apart from each other along the second direction are provided on the front side of the bearing back plate, the movable guide rails extend along the first direction, and the second bearing plate is slidably connected to the bearing back plate via the movable guide rails.

[0011] Optionally, the test assembly also includes a pressure sensor, which is located between the first supporting plate and the first flexible support member, and has at least three non-collinear detection points in contact with the first flexible support member, for detecting and obtaining pressure data applied by the first flexible support member to the pressure sensor.

[0012] Optionally, the first flexible support member comprises a first base, a first support rod, and a first bearing base coaxially connected in sequence along the first direction, and the first support rod is provided with a first hole groove symmetrically arranged along the second direction and a second hole groove symmetrically arranged along the third direction, so that the first flexible support member has rigidity in the first direction and flexibility in the second direction and the third direction;

[0013] The second flexible support member includes a second base, a second support rod, and a second bearing base coaxially connected in sequence along the second direction. The second support rod is provided with a third hole groove symmetrically arranged along the second direction and a fourth hole groove symmetrically arranged along the third direction, so that the second flexible support member has rigidity in the first direction and flexibility in the second direction and the third direction.

[0014] Optionally, the first flexible support member comprises a first base, a first support rod, and a first bearing base coaxially connected in sequence along the first direction, and the first support rod is a thin waist-shaped structure that is thin in the middle and thick at both ends, so that the first flexible support member has rigidity in the first direction and has flexibility in any direction perpendicular to the first direction;

[0015] The second flexible support member includes a second base, a second support rod, and a second bearing base coaxially connected in sequence along the first direction. The second support rod is a thin waist-shaped structure that is thin in the middle and thick at both ends, so that the second flexible support member is rigid in the first direction and flexible in any direction perpendicular to the first direction.

[0016] Optionally, the piezoelectric device is placed between the first supporting base and the second supporting base, and a first insulating layer is arranged between the first supporting base and the piezoelectric device, and a second insulating layer is arranged between the second supporting base and the piezoelectric device, so that the piezoelectric device is electrically insulated from the first flexible support member and the second flexible support member, respectively.

[0017] Optionally, the test assembly also includes a displacement sensor, the force-applying structure has a fixed end and a movable end relatively arranged along the first direction, the fixed end is fixedly connected to the second supporting plate, and the movable end is fixedly connected to the top clamping plate, and when the piezoelectric device is actuated, the top clamping plate is driven to move along the first direction, and the movable end follows the movement of the top clamping plate, and the displacement sensor is connected to the second supporting plate for detecting and obtaining the displacement data of the top clamping plate along the first direction.

[0018] The present application also provides a method for testing a piezoelectric device, using any one of the piezoelectric device testing devices in the aforementioned embodiments to test the piezoelectric device, wherein the testing device includes a pressure sensor and a displacement sensor, and the testing method includes the following steps:

[0019] Install and adjust the first flexible support and the second flexible support so that the second flexible support is coaxially arranged with the first flexible support;

[0020] Mounting the piezoelectric device to the testing device so that the piezoelectric device is coaxially disposed with the second flexible support and the first flexible support;

[0021] Starting a force-applying structure to apply a load stress or a prestress to the piezoelectric device;

[0022] Applying a voltage with a preset waveform to the piezoelectric device to make the piezoelectric device output displacement, and simultaneously starting the pressure sensor and the displacement sensor to obtain displacement data and pressure data when the piezoelectric device is in motion;

[0023] Whether the piezoelectric device is qualified is judged according to the displacement data and the pressure data.

[0024] Optionally, the step of installing and adjusting the first flexible support member and the second flexible support member so that the second flexible support member is coaxially arranged with the first flexible support member comprises the following steps:

[0025] Connecting the first flexible support member to the upper side of the pressure sensor;

[0026] Connecting the second flexible support member to the bottom of the top splint;

[0027] Moving the second supporting plate toward the first supporting plate so that the first flexible supporting member contacts the second flexible supporting member;

[0028] Acquiring pressure data detected by the pressure sensor;

[0029] According to the pressure data, the position of the first flexible support member and / or the second flexible support member is adjusted so that the pressure of the first flexible support member on the pressure sensor is evenly distributed, and the second flexible support member is coaxially arranged with the first flexible support member.

[0030] Optionally, the step of mounting the piezoelectric device on the testing device and arranging the piezoelectric device coaxially with the second flexible support member and the first flexible support member comprises the following steps:

[0031] placing the piezoelectric device between the first flexible support and the second flexible support;

[0032] Applying initial stress to the piezoelectric device using the force applying structure;

[0033] Acquiring pressure data detected by the pressure sensor;

[0034] According to the pressure data, the positions of the piezoelectric device, and / or the first flexible support member, and / or the second flexible support member are adjusted so that the pressure distribution of the pressure sensor by the first flexible support member is uniform, and the piezoelectric device is coaxially arranged with the first flexible support member and the second flexible support member.

[0035] Optionally, the initial stress is 10% to 30% of the prestress, and the prestress is greater than or equal to 10% of the output stress of the piezoelectric device and less than or equal to 70% of the output stress of the piezoelectric device.

[0036] Optionally, if the periodic variation of the pressure data conforms to the periodic variation of the preset waveform, and the displacement data reaches the preset displacement of the piezoelectric device, the current test structure is determined to be qualified; otherwise, the piezoelectric device is determined to be failed.

[0037] Optionally, when the number of driving times of the piezoelectric device reaches a preset number, and the test results corresponding to the number of driving times are all qualified, the piezoelectric device is qualified, otherwise, the piezoelectric device fails.

[0038] As described above, the testing device and testing method of the piezoelectric device provided by the present application have at least the following beneficial effects:

[0039] The test device is provided with a force-applying structure, through which prestress can be applied to the piezoelectric device under no-load test conditions, avoiding the generation of dynamic stress during the test process and adversely affecting the piezoelectric device, or different load stresses can be applied to the piezoelectric device under load test conditions to adapt to various test conditions; the decoupling between the tangential stress and the normal stress is realized by the first flexible support and the second flexible support, ensuring the transmission effect of the normal stress between the piezoelectric device and the top clamp, when subjected to tangential stress, the deformation of the first flexible support and the second flexible support greatly reduces the transmission effect of the tangential stress to the piezoelectric device, preventing the piezoelectric device from being damaged, and by replacing the first flexible support and the second flexible support, it can adapt to piezoelectric devices of various specifications. It can be seen that the test device of the present application realizes effective protection of the piezoelectric device during the test process, reduces or avoids the risk of damage to the piezoelectric device during the test process, improves the product yield, and the test device is suitable for various test conditions and product specifications, and has extremely wide applicability, and the test method of the present application uses the above-mentioned test device for testing, so it also has the above-mentioned beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0041] Figure 1 Shown is a schematic diagram of the structure of the piezoelectric device testing device provided in Example 1 of the present application.

[0042] Figure 2 Shown is a front view of the testing device provided in Example 1 of the present application.

[0043] Figure 3 Shown is a schematic structural diagram of the testing device provided in the first embodiment of the present application when viewed from the side along the second direction.

[0044] Figure 4 and Figure 5 Shown as Figure 1 A schematic diagram of the structure of the load-bearing component and the test component in the test device shown.

[0045] Figure 6 Shown is a schematic diagram of the structure of the supporting backplane in the testing device provided in Example 1 of the present application.

[0046] Figure 7 Shown is a schematic diagram of the structure of the first supporting plate in the testing device provided in Example 1 of the present application.

[0047] Figure 8 and Fig. 9 They respectively show the structural schematic diagrams of the first flexible support member and the second flexible support member in the testing device provided in Example 1 of the present application.

[0048] Fig.10 Shown is a schematic structural diagram of a first support rod or a second support rod provided in an optional embodiment of the first embodiment of the present application.

[0049] Fig.11 Shown is a schematic diagram of the structure of the first support rod or the second support rod provided in the second embodiment of the present application.

[0050] Fig.12 Shown is a flow chart of a method for testing a piezoelectric device provided in Embodiment 3 of the present application.

[0051] Fig.13 Display as Fig.12 A schematic diagram of a specific process of installing and adjusting the first flexible support member and the second flexible support member in the test method shown.

[0052] Fig.14 Display as Fig.12 A schematic diagram of a specific process of installing a piezoelectric device on a testing device in the testing method shown.

[0053] Reference numerals:

[0054] 10. Carrying assembly; 11. First carrying plate; 111. Mounting slot; 12. Second carrying plate; 13. Carrying back plate; 131. Motion guide rail; 20. Testing assembly; 21. First flexible support member; 211. First base; 212. First support rod; 2121. First hole slot; 2122. Second hole slot; 213. First bearing base; 214. First insulating layer; 22. Second flexible support member; 221. Second base; 222. Second support rod; 2221. Third hole slot; 2222. Fourth hole slot; 223. Second bearing base; 224. Second insulating layer; 23. Top clamp; 24. Force-applying structure; 25. Pressure sensor; 26. Displacement sensor. DETAILED DESCRIPTION

[0055] In order to make the technical purpose, technical solution and technical effect of the present application clearer, the technical solution in the present application will be clearly and completely described in conjunction with the embodiments below. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0056] Therefore, the following detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present application. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0057] In the description of the present application, it should be noted that the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the implementation or example are included in at least one implementation or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same implementation or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more implementations or examples in a suitable manner.

[0058] Embodiment 1

[0059] This embodiment provides a piezoelectric device testing device for testing a piezoelectric device. Optionally, the piezoelectric device may be, for example, a piezoelectric ceramic stack. Figures 1 to 3 The testing device of this embodiment includes a carrying component 10 and a testing component 20.

[0060] Reference Figure 1 and Figure 4 The bearing assembly 10 includes a first bearing plate 11, a second bearing plate 12 and a bearing back plate 13. The bearing back plate 13 has a front side and a back side that are arranged opposite to each other. The second bearing plate 12 is connected to the front side of the bearing back plate 13. Optionally, the second bearing plate 12 is slidably connected to the bearing back plate 13, and the second bearing plate 12 can move along a first direction on the bearing back plate 13. The first bearing plate 11 is arranged below the second bearing plate 12 along the first direction and is connected to the bearing back plate 13. An installation space for the test assembly 20 is formed between the first bearing plate 11 and the second bearing plate 12.

[0061] Reference Figure 2 and Figure 5 The test assembly 20 is located between the first bearing plate 11 and the second bearing plate 12. The test device may include one test assembly 20 or multiple test assemblies 20. Optionally, the number of test assemblies 20 is multiple, and the multiple test assemblies 20 are spaced apart along the second direction. For example, the test device may include two, three, four, five or more test assemblies 20. The test assembly 20 includes a first flexible support member 21, a second flexible support member 22, a top clamping plate 23 and a force-applying structure 24 arranged in sequence along the first direction. The first flexible support member 21 is located on the first bearing plate 11, and the second flexible support member 22 is located above the first flexible support member 21. Optionally, the second flexible support member 22 is coaxially arranged with the first flexible support member 21. The piezoelectric device is placed between the first flexible support member 21 and the second flexible support member 22. The force-applying structure 24 is connected to the second supporting plate 12 for applying prestress or bearing stress to the piezoelectric device. The top clamping plate 23 is located between the force-applying structure 24 and the second flexible support member 22. The prestress applied by the force-applying structure 24 is transmitted to the piezoelectric device via the top clamping plate 23 and the second flexible support member 22.

[0062] In this embodiment, the first flexible support member 21 and the second flexible support member 22 have rigidity in the first direction and flexibility in the second direction and the third direction, wherein the first direction and the second direction are parallel to the front surface of the bearing back plate 13, and the first direction, the second direction and the third direction are perpendicular to each other. Specifically, referring to Figure 1, the first direction is the z-axis direction, the second direction is the x-axis direction, and the third direction is the y-axis direction. The test device of this embodiment can effectively reduce or prevent the damage of the piezoelectric device caused by the tangential stress and the dynamic stress by applying prestress to the piezoelectric device and using the first flexible support member 21 and the second flexible support member 22, thereby improving the product yield. Moreover, the test device can adapt to various test conditions and products of different specifications, so that the test device of this embodiment has extremely wide applicability.

[0063] Reference Figure 4 and Figure 6 At least two movable guide rails 131 spaced apart from each other along the second direction are arranged on the front side of the carrying back plate 13. The movable guide rails 131 extend along the first direction. The second carrying plate 12 is slidably connected to the carrying back plate 13 through the movable guide rails 131 and can slide along the movable guide rails 131 so that the second carrying plate 12 moves toward or away from the first carrying plate 11.

[0064] In an optional embodiment, at least two guide through holes spaced apart from each other along the second direction are provided in the supporting back plate 13, and the guide through holes extend along the first direction to form a moving guide rail 131, and the second supporting plate 12 is slidably connected to the guide through holes and moves along the first direction through the guide through holes.

[0065] In an optional embodiment, the motion guide rail 131 may also be a protruding slide rail, at least two slide rails are arranged at intervals from each other along the second direction on the front of the bearing back plate 13, and are connected to the bearing back plate 13, for example, they may be fixedly connected to the bearing back plate 13 by bolts. The extension direction of the slide rail is the first direction, and the second bearing plate 12 is connected to the bearing back plate 13 through the slide rail, and moves along the first direction through the slide rail. It should be noted that the motion guide rail 131 may also be other types of structures, and this embodiment is not limited thereto.

[0066] In this embodiment, refer to Figure 1 The test assembly 20 further includes a pressure sensor 25, which is located between the first carrier plate 11 and the first flexible support member 21 and connected to the first carrier plate 11. The pressure sensor 25 has at least three detection points that are non-collinearly arranged and in contact with the first flexible support member 21, and is used to detect and obtain the pressure data applied by the first flexible support member 21 to the pressure sensor 25. Through the three detection points that are non-collinearly arranged, the plane in contact with the detection points of the first flexible support member 21 can be determined, and then the pressure data measured by the pressure sensor 25 can reflect the pressure distribution applied by the first flexible support member 21 to the pressure sensor 25, so as to determine whether the pressure applied by the piezoelectric device to the first flexible support member 21 is evenly distributed, and then it can be determined whether the working state of the piezoelectric device is normal.

[0067] In an optional embodiment, the test assembly 20 includes one or more pressure sensors 25. For example, the test assembly 20 may include one pressure sensor 25, and the pressure sensor 25 has three non-collinear detection points, or the test assembly 20 includes three non-collinear pressure sensors 25, each of which has one detection point. The pressure sensor 25 may also adopt other suitable settings to achieve the purpose of detecting the pressure of the first flexible support member 21 in this embodiment. The pressure sensor 25 and the first carrier plate 11 may be fixedly connected by bonding, or other suitable connection methods may be adopted.

[0068] In an alternative embodiment, reference Figure 7 A mounting groove 111 is also provided on the side of the first supporting plate 11 facing the second supporting plate 12, and the pressure sensor 25 is arranged in the mounting groove 111. For example, the pressure sensor 25 can be fixedly connected to the bottom of the mounting groove 111. Optionally, the mounting groove 111 extends along the third direction to the side of the first supporting plate 11 away from the supporting back plate 13 to facilitate the installation and use of the pressure sensor 25.

[0069] In the prior art, a two-end free-style test of a piezoelectric stack is used. This method cannot detect pressure data and only relies on displacement data to determine whether the piezoelectric device is qualified. The accuracy of this judgment method is low, which leads to a high defect rate of the final product, and this method cannot accurately determine the failure time of the piezoelectric device. In this embodiment, the pressure data measured by the pressure sensor 25 can monitor the working state of the piezoelectric device in real time, effectively improving the accuracy of determining whether the piezoelectric device is qualified, thereby improving the product yield, and at the same time, the accurate failure time of the piezoelectric device can be obtained, so as to facilitate the subsequent judgment of the product life.

[0070] In this embodiment, refer to Figure 8 and Fig. 9 The first flexible support member 21 includes a first base 211, a first support rod 212, and a first bearing base 213 connected in sequence along the first direction, and the second flexible support member 22 includes a second base 221, a second support rod 222, and a second bearing base 223 connected in sequence along the first direction. Optionally, the first base 211, the first support rod 212, and the first bearing base 213 are coaxially arranged, and the second base 221, the second support rod 222, and the second bearing base 223 are coaxially arranged. The first base 211 is located on the first bearing plate 11, the second base 221 is connected to the top clamping plate 23, the piezoelectric device is located between the first bearing base 213 and the second bearing base 223, the first support rod 212 is used to realize that the first flexible support member 21 has rigidity in the first direction and flexibility in the second and third directions, and the second support rod 222 is used to realize that the second flexible support member 22 has rigidity in the first direction and flexibility in the second and third directions.

[0071] Through the first flexible support member 21 and the second flexible support member 22, the decoupling effect of the tangential stress and the normal stress transmitted to the piezoelectric device is achieved, while the transmission effect of the normal stress in the first direction is guaranteed. When the first flexible support member 21 and / or the second flexible support member 22 are subjected to tangential stress, it can be decomposed into the tangential strain of the first flexible support member 21 and / or the second flexible support member 22 along the second direction and / or the third direction, thereby reducing the stress transmission effect to the piezoelectric device, reducing or avoiding the risk of damage to the piezoelectric device during the test, and improving the product yield. In addition, by replacing the first flexible support member 21 and the second flexible support member 22 of different sizes, it can adapt to piezoelectric devices of various specifications, thereby improving the applicability of the device.

[0072] In an optional embodiment, the first support rod 212 is a thin waist-shaped structure that is thin in the middle and thick at both ends, so that the first flexible support member 21 has rigidity in the first direction and is flexible in any direction perpendicular to the first direction, and the second support rod 222 is also a thin waist-shaped structure that is thin in the middle and thick at both ends, so that the second flexible support member 22 has rigidity in the first direction and is flexible in any direction perpendicular to the first direction.

[0073] Further, refer to Figure 1 and Figure 8 , taking the direction perpendicular to the first direction as the tangent direction, the first support rod 212 is a cylindrical thin waist structure, so that the first flexible support member 21 has good flexibility in any direction of the tangent direction, and realizes the multi-axis decoupling effect; or the first support rod 212 can also be an elliptical thin waist structure, which can improve the decoupling effect of the first flexible support member 21 in the narrow diameter direction of the tangent direction; refer to Fig.10 Alternatively, the first support rod 212 may be a polygonal thin waist structure, such as a rectangular thin waist structure, so that the first flexible support member 21 has a good decoupling effect in the direction of the side length of the rectangle.

[0074] Further, refer to Figure 1 and Fig. 9 The second support rod 222 is a cylindrical thin waist structure, so that the second flexible support member 22 has good flexibility in any tangential direction, achieving a multi-axis decoupling effect; or the second support rod 222 can also be an elliptical thin waist structure, which can improve the decoupling effect of the second flexible support member 22 in the tangential narrow diameter direction; refer to Fig.10 Alternatively, the second support rod 222 may be a polygonal thin waist structure, such as a rectangular thin waist structure, so that the second flexible support member 22 has a good decoupling effect in the direction of the side length of the rectangle.

[0075] In an alternative embodiment, reference Figure 8 and Fig. 9The piezoelectric device is placed between the first bearing base 213 and the second bearing base 223, a first insulating layer 214 is provided between the first bearing base 213 and the piezoelectric device, and a second insulating layer 224 is provided between the second bearing base 223 and the piezoelectric device, so as to electrically insulate the piezoelectric device from the first flexible support member 21 and the second flexible support member 22. The first insulating layer 214 and the second insulating layer 224 can be electroplated insulating layers or insulating coatings. For example, when the first flexible support member 21 and the second flexible support member 22 are made of aluminum, the first insulating layer 214 and / or the second insulating layer 224 can preferably be an aluminum oxide coating, which can achieve electrical insulation between the piezoelectric device and the first flexible support member 21 and / or the second flexible support member 22 while having good wear resistance and being easy to prepare.

[0076] In this embodiment, refer to Figure 3 The test assembly 20 also includes a displacement sensor 26. The force-applying structure 24 has a fixed end and a movable end that are relatively arranged along the first direction. The fixed end is fixedly connected to the second bearing plate 12. Optionally, the force-applying structure 24 can be fixedly connected to the second bearing plate 12 by bolts. The movable end of the force-applying structure 24 is connected to the top clamping plate 23. Optionally, the force-applying structure 24 is fixedly connected to the top clamping plate 23. For example, the top clamping plate 23 can be fixedly connected to the force-applying structure 24 by bolts, or fixedly connected to the force-applying structure 24 by bonding. The top clamping plate 23 is used to enable the force-applying structure 24 to apply uniform prestress or bearing stress to the second flexible support member 22. When the piezoelectric device is actuated, it can drive the top clamping plate 23 to move along the first direction. The movable end of the force-applying structure 24 follows the top clamping plate 23 to move. The displacement sensor 26 is connected to the second bearing plate 12 for detecting and obtaining the displacement data of the top clamping plate 23 along the first direction. Optionally, the top clamp 23 can be a rectangular plate, a cylindrical plate, or other acceptable structures, and the surface of the top clamp 23 in contact with the second flexible support member 22 completely covers the upper surface of the second flexible support member 22, so that the top clamp 23 can apply uniform prestress to the second flexible support member 22.

[0077] In an optional embodiment, the displacement sensor 26 is fixedly connected to the second supporting plate 12. For example, the displacement sensor 26 can be connected to the second supporting plate 12 by bolts. The displacement sensor 26 can be arranged above the top clamping plate 23 at intervals, or it can be a contact displacement sensor 26 in contact with the top clamping plate 23. Optionally, the displacement sensor 26 can be, for example, an optical displacement sensor 26, an eddy current displacement sensor 26, or other suitable types of sensors.

[0078] In an optional embodiment, the force-applying structure 24 can be an electric cylinder, an elastic element such as a spring, a counterweight or other suitable component. Optionally, the force-applying structure 24 is an electric cylinder, which has the advantages of fast response speed and high precision. It can apply a variety of prestresses or load stresses that meet the design requirements to the piezoelectric device, thereby avoiding damage to the piezoelectric device caused by dynamic stress generated during the test.

[0079] The testing device for piezoelectric devices provided in this embodiment realizes the decoupling effect between tangential stress and normal stress by using the first flexible support 21 and the second flexible support 22, effectively reduces or avoids the risk of damage to the piezoelectric device caused by the tangential stress, and can adapt to piezoelectric devices of various specifications by replacing the first flexible support 21 and the second flexible support 22; the force-applying structure 24 can apply prestress under no-load test conditions to avoid damage to the piezoelectric device caused by dynamic stress; in addition, the displacement sensor 26 and the pressure sensor 25 are used to detect displacement data and pressure data, so that the state of the piezoelectric device can be monitored in real time during the test process, thereby improving the accuracy of the judgment of the piezoelectric device. It can be seen that the testing device of this embodiment effectively reduces or avoids the risk of damage to the piezoelectric device caused by tangential stress, dynamic stress, etc., improves the protection effect of the piezoelectric device and the accuracy of the quality judgment of the piezoelectric device, can adapt to products of various specifications and various test scenarios, improves the product yield and the applicability of the device, and has extremely high application value and promotion value.

[0080] Embodiment 2

[0081] This embodiment provides another testing device for piezoelectric devices, which also includes the supporting component 10 and the testing component 20 in the first embodiment. The number of the testing components 20 can be one or more. The similarities with the first embodiment are not repeated here. The differences will be described in detail below with reference to the accompanying drawings.

[0082] In this embodiment, refer to Figure 8 , Fig. 9 and Fig.11The first flexible support member 21 includes a first base 211, a first support rod 212, and a first bearing base 213 connected in sequence along the first direction. Optionally, the first base 211, the first support rod 212, and the first bearing base 213 are coaxially arranged. The first support rod 212 is provided with a first hole groove 2121 symmetrically arranged along the second direction and a second hole groove 2122 symmetrically arranged along the third direction. Through the first hole groove 2121 and the second hole groove 2122, the first flexible support member 21 has rigidity in the first direction and flexibility in the second and third directions, thereby achieving decoupling between the stress transmitted in the first flexible support member 21 along the first direction and the stress along the second and third directions, so that the first flexible support member 21 decomposes the tangential stress into tangential strains along the second and third directions, thereby preventing the tangential stress from damaging the piezoelectric device.

[0083] In an alternative embodiment, reference Fig.11 The first support rod 212 has two first holes 2121 and two second holes 2122, the two first holes 2121 are symmetrically arranged on opposite sides of the first support rod 212 along the second direction, and the two second holes 2122 are symmetrically arranged on opposite sides of the first support rod 212 along the third direction. Optionally, both the first holes 2121 and the second holes 2122 are arc-shaped grooves, and in the projection surface of the first flexible support member 21 along the second direction or the third direction, the first holes 2121 and the second holes 2122 are spaced apart along the first direction.

[0084] The second flexible support member 22 includes a second base 221, a second support rod 222, and a second bearing base connected in sequence along the first direction. Optionally, the second base 221, the second support rod 222, and the second bearing base are coaxially arranged. The second support rod 222 is provided with a third hole 2221 symmetrically arranged along the second direction and a fourth hole 2222 symmetrically arranged along the third direction. Through the third hole 2221 and the fourth hole 2222, the second flexible support member 22 has rigidity in the first direction and flexibility in the second and third directions, thereby achieving decoupling between the stress along the first direction and the stress along the second and third directions transmitted by the second flexible support member 22, so that the second flexible support member 22 decomposes the tangential stress received into tangential strains along the second and third directions, thereby preventing the tangential stress from causing damage to the piezoelectric device.

[0085] In an alternative embodiment, reference Fig.11The second support rod 222 has two third holes 2221 and two fourth holes 2222, the two third holes 2221 are symmetrically arranged on opposite sides of the second support rod 222 along the second direction, and the two fourth holes 2222 are symmetrically arranged on opposite sides of the second support rod 222 along the third direction. Optionally, the third holes 2221 and the fourth holes 2222 are both arc-shaped grooves, and in the projection surface of the second flexible support member 22 along the second direction or the third direction, the third holes 2221 and the fourth holes 2222 are spaced apart along the first direction.

[0086] In the testing device of the present embodiment, the first flexible support member 21 realizes decoupling of tangential stress and normal stress through the first hole slot 2121 and the second hole slot 2122, and the second flexible support member 22 realizes decoupling of tangential stress and normal stress through the third hole slot 2221 and the fourth hole slot 2222, and can simultaneously ensure that the first flexible support member 21 and the second flexible support member 22 have a good transmission effect on the normal stress along the first direction, ensure the displacement output effect of the piezoelectric device, and further ensure the accuracy of the displacement data detected by the displacement sensor 26 and the pressure data detected by the pressure sensor 25.

[0087] Embodiment 3

[0088] This embodiment provides a method for testing a piezoelectric device, using any of the piezoelectric device testing devices described in the first embodiment or the second embodiment to test the piezoelectric device. Fig.12 The testing device of this embodiment includes a displacement sensor 26 and a pressure sensor 25. The testing method includes steps S1 to S5, specifically including:

[0089] Step S1: installing and adjusting the first flexible support member 21 and the second flexible support member 22 so that the second flexible support member 22 is coaxially arranged with the first flexible support member 21;

[0090] Step S2: installing the piezoelectric device to the testing device so that the piezoelectric device is coaxially arranged with the second flexible support member 22 and the first flexible support member 21;

[0091] Step S3: starting the force applying structure 24 to apply load stress or prestress to the piezoelectric device;

[0092] Step S4: energize the piezoelectric device and apply a voltage with a preset waveform to make the piezoelectric device output displacement, and simultaneously start the pressure sensor 25 and the displacement sensor 26 to obtain displacement data and pressure data when the piezoelectric device is in motion;

[0093] Step S5: judging whether the piezoelectric device is qualified according to the displacement data and the pressure data.

[0094] The testing method for the piezoelectric device provided in this embodiment will be described in detail below with reference to the accompanying drawings. It should be noted that the above sequence does not strictly represent the process sequence of the testing method for the piezoelectric device protected by this application, and those skilled in the art may change it according to the actual processing steps.

[0095] First, step S1 is performed to install and adjust the first flexible support member 21 and the second flexible support member 22 so that the second flexible support member 22 is coaxially arranged with the first flexible support member 21. Between the first flexible support member 21 and the second flexible support member 22 is the installation space of the piezoelectric device. According to the specifications of the piezoelectric device to be tested, the first flexible support member 21 and the second flexible support member 22 corresponding to the specifications and sizes are installed to the test device, and the relative position between the two is adjusted so that the first flexible support member 21 and the second flexible support member 22 are coaxially arranged.

[0096] In an alternative embodiment, reference Fig.13 , executing step S1 specifically includes steps S11 to S15.

[0097] S11: Connect the first flexible support member 21 to the top of the pressure sensor 25. Optionally, the first flexible support member 21 may be bonded to the top of the pressure sensor 25 so that the position of the first flexible support member 21 remains relatively stable.

[0098] S12: Connect the second flexible support member 22 to the bottom of the top clamping plate 23. Optionally, the second flexible support member 22 can be fixedly connected to the bottom of the top clamping plate 23 by bolts, or can be connected to the bottom of the top clamping plate 23 by bonding.

[0099] S13: Move the second carrier plate 12 toward the first carrier plate 11. Specifically, slide the second carrier plate 12 downward along the first direction to make the first flexible support member 21 contact the second flexible support member 22, and optionally, move the second carrier plate 12 downward to make the first flexible support member 21 abut against the second flexible support member 22.

[0100] S14: Obtaining pressure data detected by the pressure sensor 25 .

[0101] S15: According to the pressure data, adjust the position of the first flexible support member 21 and / or the second flexible support member 22. Specifically, adjust the relative position between the first flexible support member 21 and the pressure sensor 25, and / or between the first flexible support member 21 and the second flexible support member 22 in a plane perpendicular to the first direction, so that the pressure distribution of the first flexible support member 21 on the pressure sensor 25 is uniform, and the second flexible support member 22 is coaxially arranged with the first flexible support member 21.

[0102] In an optional embodiment, before executing steps S11 to S15 , the following step is further included: controlling the second supporting plate 12 to move away from the first supporting plate 11 along the first direction to provide installation space for the first flexible support member 21 and the second flexible support member 22 .

[0103] By adjusting the relative positions of the first flexible support member 21, the pressure sensor 25 and the second flexible support member 22, it is possible to ensure that during the test, the pressure distribution between the piezoelectric device and the first flexible support member 21 and the second flexible support member 22 is uniform, thereby reducing the risk of damage to the piezoelectric device, and enabling the pressure data measured by the pressure sensor 25 to more intuitively reflect the stress transfer between the piezoelectric device and the first flexible support member 21, and further reflect the working condition and product quality of the piezoelectric device, so as to facilitate judgment on whether the piezoelectric device is qualified.

[0104] Then, step S2 is performed to install the piezoelectric device to the test device, and the piezoelectric device is coaxially arranged with the first flexible support member 21 and the second flexible support member 22. Piezoelectric devices such as piezoelectric ceramic stacks are sensitive to stress during the transfer process and can only withstand normal stress, but not shear stress or torsional force. Specifically, refer to Fig.14 In this embodiment, step S2 includes steps S21 to S24.

[0105] S21: placing the piezoelectric device between the first flexible support member 21 and the second flexible support member 22. Specifically, the second support plate 12 is moved away from the first support plate 11 to form an installation space for the piezoelectric device between the first flexible support member 21 and the second flexible support member 22, the piezoelectric device is placed on the first flexible support member 21, and the position of the first flexible support member 21 is adjusted so that the piezoelectric device and the first flexible support member 21 are coaxially arranged, and the second support plate 12 is controlled to approach the first support plate 11 along the first direction so that the second flexible support member 22 contacts the piezoelectric device.

[0106] In an optional embodiment, the piezoelectric device and the first flexible support member 21 and the second flexible support member 22 can be connected by bonding, or a groove is provided on the side of the first flexible support member 21 and the second flexible support member 22 facing the piezoelectric device, and the piezoelectric device is stuck in the groove, or the piezoelectric device and the first flexible support member 21 and the second flexible support member 22 can also be connected by other suitable methods to maintain the stability of the relative position between the piezoelectric device and the first flexible support member 21 and the second flexible support member 22.

[0107] S22: applying initial stress to the piezoelectric device using the force applying structure 24. Optionally, the initial stress is 10% to 30% of the prestress, for example, the initial stress may be 10%, 15%, 20%, 25%, 30% or other suitable values ​​of the prestress.

[0108] S23: Obtaining pressure data detected by the pressure sensor 25 .

[0109] S24: According to the pressure data, adjust the position of the piezoelectric device, and / or the first flexible support member 21, and / or the second flexible support member 22, so that the pressure distribution of the first flexible support member 21 on the pressure sensor 25 is uniform, and the piezoelectric device is coaxially arranged with the first flexible support member 21 and the second flexible support member 22.

[0110] During the installation and debugging of the piezoelectric device, by applying initial stress and obtaining pressure data based on detection, it is possible to determine whether the pressure of the first flexible support 21 on the pressure sensor 25 is evenly distributed, and then to determine whether the position of the piezoelectric device is correctly installed. In addition, by controlling the value range of the initial stress, it is possible to not only meet the purpose of determining whether the position of the piezoelectric device is correct, but also reduce the risk of damage to the piezoelectric device due to displacement.

[0111] Next, step S3 is executed to start the force-applying structure 24 to apply load stress or prestress to the piezoelectric device. Specifically, when the piezoelectric device needs to be tested under load conditions, a preset load stress is applied to the piezoelectric device through the force-applying structure 24; when the piezoelectric device needs to be tested under no-load conditions, a preset prestress is applied to the piezoelectric device through the force-applying structure 24. Optionally, the prestress is greater than or equal to 10% of the output stress of the piezoelectric device, and less than or equal to 70% of the output stress of the piezoelectric device. For example, the prestress can be 10%, 30%, 50%, 70% or other suitable values ​​of the output stress of the piezoelectric device.

[0112] In this embodiment, the output stress of the piezoelectric device should be understood as the rated output stress of the piezoelectric device. The force-applying structure 24 can apply a preset load stress to the piezoelectric device under load test conditions to meet various test conditions. By applying prestress to the piezoelectric device under no-load test conditions, the generation of dynamic stress during the test process and damage to the piezoelectric device can be effectively prevented.

[0113] Next, step S4 is executed to apply a voltage with a preset waveform to the piezoelectric device so that the piezoelectric device outputs a displacement, and the pressure sensor 25 and the displacement sensor 26 are started at the same time to obtain the displacement data and pressure data when the piezoelectric device is in action. Specifically, the piezoelectric device outputs a displacement along the first direction under the action of the voltage, thereby driving the top clamp 23 to move along the first direction. After the displacement sensor 26 is started and reset to zero, the displacement data of the top clamp 23 can be detected by the displacement sensor 26, and the pressure data during the test can be detected in real time by the pressure sensor 25. It should be noted that the pressure sensor 25 and the displacement sensor 26 can be started in step S4, or before executing step S4.

[0114] Finally, step S5 is executed to determine whether the piezoelectric device is qualified according to the displacement data and the pressure data. By combining the pressure data with the displacement data to determine whether the piezoelectric device is qualified, the displacement output performance of the piezoelectric device and the structural stability of the piezoelectric device body can be tested at the same time, thereby improving the accuracy of determining whether the piezoelectric device is qualified and the product yield.

[0115] In an optional embodiment, if the periodic variation of the pressure data detected conforms to the periodic variation of the preset voltage waveform, and at the same time, the displacement data can reach the preset displacement of the piezoelectric device, then the current test result is determined to be qualified, that is, the current piezoelectric device meets the design requirements, otherwise, the piezoelectric device is determined to be failed. Specifically, when the displacement data does not reach the preset displacement of the piezoelectric device, or the periodic variation of the pressure data does not conform to the periodic variation of the preset voltage waveform, the piezoelectric device fails.

[0116] In an optional embodiment, when the number of times the piezoelectric device is driven reaches a preset number of times, and the test results corresponding to the number of times of driving are all qualified, the piezoelectric device is qualified, otherwise, the piezoelectric device fails. Specifically, when the number of times the piezoelectric device is driven reaches a preset number of times, and the test results corresponding to the number of times of driving are all qualified when the number of times of driving is the preset number of times and below, the piezoelectric device is judged to be qualified.

[0117] In an optional embodiment, step S5 also includes the following steps: when the displacement data does not reach the preset displacement, or the periodic change of the pressure data does not conform to the periodic change of the preset voltage waveform, the product failure time is recorded. When the piezoelectric device is judged to be failed by the displacement data and the pressure data, the accurate product failure time can be obtained, and the product life can be calculated based on the product failure time. For example, after the piezoelectric device is judged to be qualified, the piezoelectric product is continuously tested. When the displacement data does not reach the preset displacement, or the periodic change of the pressure data does not conform to the periodic change of the preset voltage waveform, the product failure time is recorded, thereby realizing the judgment of the product life.

[0118] This embodiment provides a method for testing a piezoelectric device, which is tested using any of the piezoelectric device testing devices described in the first or second embodiment, and thus has the same beneficial effects as the first and second embodiments.

[0119] The above embodiments are merely illustrative of the principles and effects of the present application and are not intended to limit the present application. Anyone familiar with the technology may modify, change or combine the above embodiments without violating the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed in the present application shall still be covered by the claims of the present application.

Claims

1. A piezoelectric device testing device, characterized in that: It comprises a bearing assembly (10) and one or more test assemblies (20) spaced apart and distributed along a second direction; The bearing assembly (10) comprises a first bearing plate (11), a second bearing plate (12) and a bearing back plate (13); the bearing back plate (13) has a front side and a back side arranged opposite to each other; the second bearing plate (12) is slidably connected to the front side of the bearing back plate (13) and is capable of moving along a first direction; the first bearing plate (11) is spaced below the second bearing plate (12) along the first direction and is connected to the front side of the bearing back plate (13); The test assembly (20) is located between the first bearing plate (11) and the second bearing plate (12), and comprises a first flexible support member (21), a second flexible support member (22), a top clamping plate (23) and a force-applying structure (24) arranged in sequence along the first direction, the first flexible support member (21) is located on the first bearing plate (11), the second flexible support member (22) is coaxially arranged above the first flexible support member (21) along the first direction, the piezoelectric device is placed between the first flexible support member (21) and the second flexible support member (22), and the force-applying structure (24) is connected to the second bearing plate (12) and is used to apply prestress or bearing stress to the piezoelectric device; The first flexible support member (21) and the second flexible support member (22) are rigid in the first direction and flexible in the second direction and a third direction, the first direction and the second direction are both parallel to the front surface of the bearing back plate (13), and the first direction, the second direction and the third direction are perpendicular to each other.

2. The piezoelectric device testing device according to claim 1, characterized in that: At least two movable guide rails (131) spaced apart from each other along the second direction are arranged on the front side of the bearing back plate (13); the movable guide rails (131) extend along the first direction; and the second bearing plate (12) is slidably connected to the bearing back plate (13) via the movable guide rails (131).

3. The piezoelectric device testing device according to claim 1, characterized in that: The test assembly (20) further comprises a pressure sensor (25), wherein the pressure sensor (25) is located between the first bearing plate (11) and the first flexible support member (21), and has at least three non-collinear detection points in contact with the first flexible support member (21), and is used to detect and obtain pressure data applied by the first flexible support member (21) to the pressure sensor (25).

4. The piezoelectric device testing device according to claim 1, characterized in that: The first flexible support member (21) comprises a first base (211), a first support rod (212), and a first bearing base (213) which are coaxially connected in sequence along the first direction; the first support rod (212) is provided with a first hole groove (2121) symmetrically arranged along the second direction and a second hole groove (2122) symmetrically arranged along the third direction, so that the first flexible support member (21) has rigidity in the first direction and flexibility in the second direction and the third direction; The second flexible support member (22) comprises a second base (221), a second support rod (222), and a second bearing base (223) which are coaxially connected in sequence along the first direction, and the second support rod (222) is provided with a third hole groove (2221) symmetrically arranged along the second direction and a fourth hole groove (2222) symmetrically arranged along the third direction, so that the second flexible support member (22) has rigidity in the first direction and flexibility in the second direction and the third direction.

5. The piezoelectric device testing device according to claim 1, characterized in that: The first flexible support member (21) comprises a first base (211), a first support rod (212), and a first bearing base (213) which are coaxially connected in sequence along the first direction, the first support rod (212) being a thin waist-shaped structure thin in the middle and thick at both ends, so that the first flexible support member (21) has rigidity in the first direction and flexibility in any direction perpendicular to the first direction; The second flexible support member (22) comprises a second base (221), a second support rod (222), and a second bearing base (223) which are coaxially connected in sequence along the first direction, and the second support rod (222) is a thin waist-shaped structure which is thin in the middle and thick at both ends, so that the second flexible support member (22) has rigidity in the first direction and has flexibility in any direction perpendicular to the first direction.

6. The piezoelectric device testing device according to claim 5, characterized in that: The piezoelectric device is placed between the first supporting base (213) and the second supporting base (223), and a first insulating layer (214) is provided between the first supporting base (213) and the piezoelectric device, and a second insulating layer (224) is provided between the second supporting base (223) and the piezoelectric device, so that the piezoelectric device is electrically insulated from the first flexible support member (21) and the second flexible support member (22), respectively.

7. The piezoelectric device testing device according to claim 1, characterized in that: The test assembly (20) further comprises a displacement sensor (26); the force-applying structure (24) comprises a fixed end and a movable end which are arranged opposite to each other along the first direction; the fixed end is fixedly connected to the second supporting plate (12); the movable end is fixedly connected to the top clamping plate (23); when the piezoelectric device is actuated, the top clamping plate (23) is driven to move along the first direction; the movable end moves along with the top clamping plate (23); the displacement sensor (26) is connected to the second supporting plate (12) and is used to detect and obtain displacement data of the top clamping plate (23) along the first direction.

8. A method for testing a piezoelectric device, using the piezoelectric device testing device according to any one of claims 1 to 7 to test the piezoelectric device, wherein the testing device comprises a pressure sensor (25) and a displacement sensor (26), and is characterized in that: The following steps are involved: Installing and adjusting the first flexible support member (21) and the second flexible support member (22) so that the second flexible support member (22) is coaxially arranged with the first flexible support member (21); Mounting the piezoelectric device on the testing device, and arranging the piezoelectric device, the second flexible support member (22) and the first flexible support member (21) coaxially; Starting a force-applying structure (24) to apply a load stress or a prestress to the piezoelectric device; Applying a voltage having a preset waveform to the piezoelectric device so that the piezoelectric device outputs a displacement, and simultaneously starting the pressure sensor (25) and the displacement sensor (26) to obtain displacement data and pressure data when the piezoelectric device is in motion; Whether the piezoelectric device is qualified is judged according to the displacement data and the pressure data.

9. The method for testing a piezoelectric device according to claim 8, characterized in that: The step of installing and adjusting the first flexible support member (21) and the second flexible support member (22) so that the second flexible support member (22) is coaxially arranged with the first flexible support member (21) comprises the following steps: Connecting the first flexible support member (21) to the upper side of the pressure sensor (25); Connecting the second flexible support member (22) to the bottom of the top clamping plate (23); Moving the second supporting plate (12) in a direction close to the first supporting plate (11) so that the first flexible supporting member (21) contacts the second flexible supporting member (22); Acquiring pressure data detected by the pressure sensor (25); According to the pressure data, the position of the first flexible support member (21) and / or the second flexible support member (22) is adjusted so that the pressure distribution of the first flexible support member (21) on the pressure sensor (25) is uniform, and the second flexible support member (22) is arranged coaxially with the first flexible support member (21).

10. The method for testing a piezoelectric device according to claim 8, characterized in that: The step of mounting the piezoelectric device on the testing device and arranging the piezoelectric device coaxially with the second flexible support member (22) and the first flexible support member (21) comprises the following steps: Placing the piezoelectric device between the first flexible support member (21) and the second flexible support member (22); Using the force applying structure (24) to apply initial stress to the piezoelectric device; Acquiring pressure data detected by the pressure sensor (25); According to the pressure data, the positions of the piezoelectric device, and / or the first flexible support member (21), and / or the second flexible support member (22) are adjusted so that the pressure distribution of the first flexible support member (21) on the pressure sensor (25) is uniform, and the piezoelectric device is coaxially arranged with the first flexible support member (21) and the second flexible support member (22).

11. The method for testing a piezoelectric device according to claim 10, characterized in that: The initial stress is 10% to 30% of the prestress, and the prestress is greater than or equal to 10% of the output stress of the piezoelectric device and less than or equal to 70% of the output stress of the piezoelectric device.

12. The method for testing a piezoelectric device according to claim 8, characterized in that: If the periodic variation of the pressure data conforms to the periodic variation of the preset waveform, and the displacement data reaches the preset displacement of the piezoelectric device, the current test result is determined to be qualified; otherwise, the piezoelectric device is determined to be failed.

13. The method for testing a piezoelectric device according to claim 8 or 12, characterized in that: When the driving times of the piezoelectric device reaches a preset number of times, and the test results corresponding to the driving times are all qualified, the piezoelectric device is qualified; otherwise, the piezoelectric device fails.

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