Piezoelectric actuator and packaging method

Abstract

The present application belongs to the field of micro-drive technology, and provides a piezoelectric actuator, including a shell structure, a piezoelectric structure, a protective layer, a filling packaging layer and a transmission output structure. A accommodating space with a first opening is arranged in the shell structure, the piezoelectric structure is connected to the bottom of the accommodating space, the transmission output structure is located at the first opening to output the displacement generated by the piezoelectric structure, the protective layer is located between the shell structure and the piezoelectric structure, the filling packaging layer is located between the protective layer and the shell structure, and can support the travel surface of the piezoelectric structure to prevent damage to the piezoelectric structure. The protective layer includes an anti-sticking layer and an elastic packaging layer, which can reduce the resistance of the piezoelectric structure during movement and avoid hard contact between the piezoelectric structure and the filling packaging layer, thereby further improving the protection effect on the piezoelectric structure, thereby improving the structural stability and working reliability of the product. In addition, the present application also provides a packaging method for packaging the above-mentioned piezoelectric actuator.

Description

Technical Field

[0001] The present application relates to the field of micro-drive technology, and in particular to a piezoelectric actuator and a packaging method. Background Art

[0002] A piezoelectric actuator is a device that uses the inverse piezoelectric effect of piezoelectric materials to achieve precise displacement control. Piezoelectric materials, such as piezoelectric ceramics, have unique physical properties: when voltage is applied to them, the piezoelectric material will deform and produce displacement, and when mechanical stress is applied to them, the piezoelectric material will generate an electric charge. Piezoelectric actuators are usually formed by stacking multiple layers of piezoelectric materials to form a piezoelectric stack structure. Electrodes are usually connected to both ends of the piezoelectric stack. When a certain voltage is applied to the piezoelectric stack, according to the inverse piezoelectric effect, the piezoelectric stack will deform along the axial direction of its stack, so that the entire piezoelectric stack can provide a large displacement output, and the displacement it produces is precisely controllable, with high accuracy, fast reading response and other characteristics, suitable for a variety of applications requiring high-precision positioning.

[0003] At present, the prestressed piezoelectric actuators on the market include a piezoelectric ceramic stack, a base, an output pusher and a housing. The base and the output pusher are respectively connected to the two opposite ends of the piezoelectric ceramic stack in the axial direction, and the housing is sleeved on the outer periphery of the piezoelectric ceramic stack, the output pusher and the base. Due to the limitation of assembly accuracy, the piezoelectric actuator will inevitably be affected by tangential impact during use, causing the piezoelectric ceramic stack to be subjected to large tangential stress, which can easily cause the stack to break and cause product damage. In addition, a longer piezoelectric ceramic stack is required for longer stroke conditions, further increasing the risk of stack breakage.

[0004] Based on this, in order to solve the above problems, the present application provides a piezoelectric actuator and a packaging method to reduce or prevent the risk of fracture of the piezoelectric ceramic stack. 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 piezoelectric actuator and a packaging method to solve the problems existing in the prior art that the piezoelectric actuator is prone to fracture damage due to tangential force and / or tangential impact.

[0006] To achieve the above objectives and other related objectives, the present application provides a piezoelectric actuator, comprising:

[0007] A shell structure, wherein a receiving space is provided inside the shell structure, and a first opening is provided at one end of the receiving space;

[0008] a piezoelectric structure, located in the accommodation space, having a top surface and a bottom surface arranged opposite to each other and a side surface connecting the top surface and the bottom surface, wherein the bottom surface of the piezoelectric structure is connected to the bottom of the accommodation space away from the first opening, and wherein the piezoelectric structure comprises a plurality of piezoelectric elements, wherein the plurality of piezoelectric elements are stacked and arranged in sequence from the bottom of the accommodation space toward the first opening; and the stacking direction of the plurality of piezoelectric elements is the first direction;

[0009] A protective layer, located between the housing structure and the piezoelectric structure, comprising an anti-sticking layer, wherein the anti-sticking layer at least covers a portion of a side surface of the piezoelectric structure;

[0010] A filling packaging layer, located between the protective layer and the shell structure, covering at least a portion of the protective layer, and spaced apart from the piezoelectric structure;

[0011] The transmission output structure is located on a side of the piezoelectric structure close to the first opening and is used to output the displacement generated by the piezoelectric structure along the first direction.

[0012] Optionally, the protective layer further includes an elastic packaging layer, which is located between the anti-sticking layer and the piezoelectric structure and is spaced apart from the filling packaging layer, and the elastic packaging layer at least covers a portion of the side surfaces of the piezoelectric structure.

[0013] Optionally, the filling encapsulation layer includes a plurality of filling segments, and the plurality of filling segments are sequentially arranged at intervals along the first direction.

[0014] Optionally, the shell structure includes a packaging shell and a packaging base, the bottom surface of the piezoelectric structure is connected to the packaging base, the first opening is arranged at one end of the packaging shell, and the end of the packaging shell away from the first opening is connected to the packaging base, so that the packaging shell is sleeved on the outer periphery of the packaging base and the piezoelectric structure, and the packaging shell is spaced apart from the piezoelectric structure.

[0015] Optionally, when looking down at the piezoelectric actuator along the first direction, the packaging shell has a circular ring-shaped outline or a rectangular ring-shaped outline, and the piezoelectric structure has a circular outline or a rectangular outline.

[0016] Optionally, the transmission output structure includes a transmission base and a transmission output member, and the transmission output member is connected to the surface of the transmission base away from the piezoelectric structure; wherein, when looking down at the piezoelectric actuator along the first direction, the outer contour line of the transmission output member is located within the outer contour line of the transmission base.

[0017] Optionally, the piezoelectric actuator further comprises:

[0018] a cover plate, arranged at intervals along the first direction on a side of the transmission base away from the piezoelectric structure, and fixedly connected to the housing structure, the cover plate having a through hole penetrating along the first direction, and the transmission output member passing through the through hole;

[0019] The elastic member surrounds the outer side of the transmission output member and is located between the cover plate and the transmission base.

[0020] Optionally, the piezoelectric actuator further includes an isolation gasket, which is located between the transmission output structure and the piezoelectric structure, connected to the piezoelectric structure, and in sliding contact with the transmission output structure.

[0021] The present application also provides a packaging method for a piezoelectric actuator, which is used to package and form any of the piezoelectric actuators described in the aforementioned embodiments, and comprises the following steps:

[0022] A piezoelectric structure, a housing structure and a transmission output structure are provided, wherein a receiving space is provided in the housing structure, and a first opening is provided at one end of the receiving space;

[0023] forming a protective layer on the side of the piezoelectric structure;

[0024] Fixedly connecting the piezoelectric structure to the bottom of the accommodation space;

[0025] forming a filling packaging layer between the protective layer and the shell structure;

[0026] The transmission output structure is mounted to the first opening of the housing structure to output the displacement generated by the piezoelectric structure along the first direction.

[0027] Optionally, the protective layer includes an anti-sticking layer and an elastic packaging layer, and the forming of the protective layer on the side of the piezoelectric structure includes the following steps:

[0028] forming an elastic packaging layer on the side of the piezoelectric structure;

[0029] The anti-sticking layer is formed on the surface of the elastic packaging layer, and the anti-sticking layer completely covers the elastic packaging layer.

[0030] Optionally, the housing structure includes a packaging housing and a packaging base, and the step of fixing the piezoelectric structure to the bottom of the accommodating space includes the following steps:

[0031] Fixedly connecting the piezoelectric structure to the package base;

[0032] The packaging shell is sleeved on the periphery of the piezoelectric structure and fixedly connected to the packaging base.

[0033] Optionally, the transmission output structure includes a transmission base and a transmission output member, and the piezoelectric actuator further includes a cover plate and an elastic member. After the transmission output structure is installed at the first opening of the housing structure, the following steps are further included:

[0034] The elastic member is sleeved on the outer periphery of the transmission output member;

[0035] The cover plate is sleeved on the outer periphery of the transmission output member, and the elastic member is pressed downward in a direction close to the transmission base, so that the elastic member abuts against the transmission base;

[0036] The cover plate is fixedly connected to the housing structure.

[0037] As described above, the piezoelectric actuator and packaging method provided by the present application have at least the following beneficial effects:

[0038] The piezoelectric actuator of the present application includes a protective layer and a filling packaging layer, wherein the filling packaging layer can support the travel surface of the piezoelectric structure, fully decompose the impact energy, and avoid damage to the piezoelectric structure caused by excessive local stress. The anti-sticking layer of the protective layer can avoid adhesion between the filling packaging layer and the piezoelectric structure, which helps to reduce the movement resistance of the piezoelectric structure and ensure the displacement output of the piezoelectric actuator; further, the protective layer includes an elastic packaging layer to avoid hard contact between the piezoelectric structure and the filling packaging layer, which can reduce the constraint of the piezoelectric structure in the displacement direction and further ensure the stable output of the piezoelectric actuator. Therefore, the piezoelectric brake of the present application can apply elastic constraints to the piezoelectric structure when subjected to a tangential impact, effectively reduce or avoid the risk of damage to the piezoelectric structure, and at the same time, while ensuring the protection effect on the piezoelectric structure, effectively reduce the resistance of the piezoelectric actuator during operation, improve the structural stability and working reliability of the product, and then improve the applicability of the piezoelectric actuator, so that it can adapt to a variety of complex application scenarios, effectively overcome the various defects in the prior art, and have a high industrial application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] 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.

[0040] Figure 1 Shown is a schematic structural diagram of a piezoelectric actuator provided in Example 1 of the present application.

[0041] Figure 2 Shown is a specific structural schematic diagram of the piezoelectric actuator housing structure provided in Example 1 of the present application.

[0042] Figure 3 It shows a schematic diagram of the structure in which a protective layer provided in the first embodiment of the present application covers part of the side surface of the piezoelectric structure.

[0043] Figure 4 It is a schematic diagram showing the structure of a piezoelectric actuator in the prior art.

[0044] Figure 5 Shown is a schematic structural diagram of a piezoelectric actuator with an elastic packaging layer provided in Example 1 of the present application.

[0045] Figures 6 to 9 Schematic diagrams of the structures of four cross sections of the piezoelectric actuator provided in the first embodiment of the present application along a direction perpendicular to the first direction are shown respectively.

[0046] Fig.10 and Fig.11 Shown is a schematic structural diagram of a piezoelectric actuator having two filling segments and three filling segments respectively provided in Example 1 of the present application.

[0047] Fig.12 Shown is a schematic structural diagram of a piezoelectric actuator with an isolation gasket provided in Example 1 of the present application.

[0048] Fig.13 Shown is a schematic flow chart of a packaging method for a piezoelectric actuator provided in the second embodiment of the present application.

[0049] Fig.14 It is a schematic diagram of a structure in which a protective layer is formed on the side of a piezoelectric structure provided in the second embodiment of the present application.

[0050] Fig.15 Shown is a schematic diagram of the structure of forming a filling packaging layer provided in the second embodiment of the present application.

[0051] Fig.16 Shown is a schematic diagram of the structure for fixing a piezoelectric structure to a package base provided in the second embodiment of the present application.

[0052] Reference numerals:

[0053] 1. Shell structure; 11. Package shell; 12. Package base; 101. Accommodating space; 102. First opening; 2. Piezoelectric structure; 21. Piezoelectric element; 3. Protective layer; 31. Anti-sticking layer; 32. Elastic packaging layer; 4. Filling packaging layer; 41. Filling section; 5. Transmission output structure; 51. Transmission output member; 52. Transmission base; 61. Cover plate; 611. Through hole; 62. Elastic member; 7. Isolation gasket; 81. Piezoelectric ceramic stack; 82. Shell base; 83. Output push head; 84. Shell. DETAILED DESCRIPTION

[0054] 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.

[0055] 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.

[0056] 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.

[0057] Embodiment 1

[0058] This embodiment provides a piezoelectric actuator for solving the problem in the prior art that the piezoelectric stack is easily damaged when the piezoelectric actuator is subjected to tangential stress. Figure 1 The piezoelectric actuator provided in this embodiment includes a shell structure 1, a piezoelectric structure 2, a protective layer 3, a filling packaging layer 4 and a transmission output structure 5.

[0059] Reference Figure 1 and Figure 2 , a housing space 101 is provided in the housing structure 1, a first opening 102 is provided at one end of the housing space 101, the housing space 101 is used to install and fix the piezoelectric structure 2, and the transmission output structure 5 at the first opening 102 is the external installation positioning structure and displacement output structure of the piezoelectric actuator. In practical applications, the housing structure 1 is generally a metal workpiece or a ceramic workpiece, which plays a role in protecting the internal piezoelectric structure 2; specifically, the material of the housing structure 1 can be stainless steel, copper alloy, titanium alloy or other suitable materials.

[0060] The piezoelectric structure 2 is arranged in the accommodation space 101. The piezoelectric structure 2 is a displacement generating structure, having a top surface and a bottom surface arranged opposite to each other and a side surface connecting the top surface and the bottom surface. The bottom surface of the piezoelectric structure 2 is connected to the bottom of the accommodation space 101 away from the first opening 102. The piezoelectric structure 2 includes a plurality of piezoelectric elements 21, which are stacked and arranged in sequence from the bottom of the accommodation space 101 to the direction close to the first opening 102, wherein the stacking direction of the plurality of piezoelectric elements 21 is taken as the first direction. In practical applications, when a certain voltage is applied to the piezoelectric structure 2, due to the inverse piezoelectric effect of the piezoelectric material, the piezoelectric structure 2 generates a certain deformation along the first direction, and the deformation is transmitted to the transmission output structure 5 to form a displacement output.

[0061] In an optional embodiment, the piezoelectric element 21 is a piezoelectric ceramic single chip, and multiple piezoelectric ceramic single chips are stacked in sequence from the bottom of the accommodating space 101 to form a piezoelectric ceramic stack, which effectively increases the length of the piezoelectric structure 2 along the first direction, thereby improving the displacement output of the piezoelectric actuator.

[0062] Reference Figure 1 and Figure 3 The protective layer 3 is arranged between the shell structure 1 and the piezoelectric structure 2, and is used to protect the piezoelectric structure 2, prevent the piezoelectric structure 2 from being damaged when the piezoelectric actuator is subjected to a tangential impact, and reduce the constraint on the displacement of the piezoelectric structure 2 along the first direction; the protective layer 3 includes an anti-sticking layer 31, and the anti-sticking layer 31 at least covers a portion of the side surface of the piezoelectric structure 2, and is used to reduce the resistance of the piezoelectric structure 2 when the piezoelectric structure 2 moves. Optionally, the anti-sticking layer 31 can cover a portion of the side surface of the piezoelectric structure 2, or cover the entire side surface of the piezoelectric structure 2, for example, the anti-sticking layer 31 covers the side surface of the piezoelectric structure 2 except for the area near the first opening 102 and the bottom of the accommodating space 101.

[0063] The filling packaging layer 4 is formed between the protective layer 3 and the shell structure 1, covers at least part of the protective layer 3, and is spaced apart from the piezoelectric structure 2. The filling packaging layer 4 can support the travel surface (side) of the piezoelectric structure 2, fully decompose the impact energy generated by the tangential stress, avoid damage to the piezoelectric structure 2 due to excessive local stress, and cooperate with the protective layer 3 to ensure the stable output of the piezoelectric actuator. Optionally, the material of the filling packaging layer 4 can be a high-rigidity packaging glue, a composite material or other suitable material. Further, the material of the filling packaging layer 4 is, for example, a packaging epoxy glue.

[0064] It should be noted that, in order to ensure the motion output of the piezoelectric structure 2 , the part of the side surface of the piezoelectric structure 2 covered by the anti-sticking layer 31 should be larger than or equal to the contact surface between the filling packaging layer 4 and the piezoelectric structure 2 .

[0065] The transmission output structure 5 is located on one side of the piezoelectric structure 2 close to the first opening 102 , passes through the first opening 102 and extends to the outside of the accommodating space 101 , and is used to output the displacement generated by the piezoelectric structure 2 along the first direction. Optionally, the transmission output structure 5 is spaced apart from the side wall of the first opening 102 .

[0066] In the prior art, reference Figure 4 The structure of the prestressed piezoelectric actuator is composed of a piezoelectric ceramic stack 81, a shell base 82, an output push head 83 and an outer shell 84. Some space is reserved between the piezoelectric ceramic stack 81 and the outer shell 84 to facilitate installation and prevent affecting the actuation effect. When the piezoelectric actuator is subjected to a tangential impact perpendicular to the first direction, the tangential force will be transmitted to the piezoelectric ceramic stack 81. Due to the brittleness of the piezoelectric ceramic stack 81 and the bridge structure connecting its two ends, it is very easy to cause damage such as fracture when subjected to tangential stress. There is a high risk of product damage during product transportation, installation and use. In the piezoelectric actuator provided in the present embodiment, a filling packaging layer 4 is arranged between the piezoelectric structure 2 and the shell structure 1, which can improve the tangential constraint effect on the piezoelectric structure 2 when the product is subjected to a tangential impact, reduce the risk of the piezoelectric structure 2 breaking or avoid the piezoelectric structure 2 from breaking. At the same time, a protective layer 3 is also provided to reduce the constraint on the output displacement of the piezoelectric structure 2 along the first direction, reduce the resistance of the piezoelectric actuator during operation, effectively improve the structural stability and reliability of the product, and enable the piezoelectric actuator to be suitable for a variety of complex scenarios.

[0067] In an optional embodiment, the anti-sticking layer 31 may be an oily coating or a nano-coating, which can effectively reduce the resistance of the piezoelectric structure 2 during operation.

[0068] In an alternative embodiment, reference Figure 5 The protective layer 3 also includes an elastic packaging layer 32, which is formed between the anti-sticking layer 31 and the piezoelectric structure 2 and is spaced apart from the filling packaging layer 4 to reduce the constraint of the piezoelectric structure 2 during operation. Optionally, the elastic packaging layer 32 covers at least part of the side surface of the piezoelectric structure 2, for example, the elastic packaging layer 32 may cover part of the side surface of the piezoelectric structure 2, or cover the entire side surface of the piezoelectric structure 2, for example, the elastic packaging layer 32 covers the side surface of the piezoelectric structure 2 except for the area near the first opening 102 and the bottom of the accommodating space 101, and the anti-sticking layer 31 completely covers the elastic packaging layer 32.

[0069] Furthermore, the elastic packaging layer 32 is made of an elastic material. Optionally, the elastic packaging layer 32 may be, for example, a polyurethane coating, a rubber coating, a graphite coating, or other suitable material coatings. In practical applications, the piezoelectric structure 2 may have poor straightness along the first direction, so that after the piezoelectric actuator is potted, the movement straightness of the piezoelectric structure 2 is poor, resulting in movement obstruction. The elastic packaging layer 32 made of an elastic material further reduces the resistance of the piezoelectric structure 2 to displacement along the first direction, ensures the stable output of the piezoelectric actuator, and applies elastic constraints to the piezoelectric structure 2 when the piezoelectric actuator is tangentially displaced, effectively preventing the piezoelectric structure 2 from being broken or damaged when the piezoelectric actuator is subjected to a tangential impact, thereby further improving the structural stability and reliability of the piezoelectric actuator.

[0070] In an alternative embodiment, reference Figure 1 The shell structure 1 can be an integrated structure or a discrete structure. For example, the shell structure 1 includes a package shell 11 and a package base 12. The package shell 11 is sleeved on the outer periphery of the package base 12 and the piezoelectric structure 2 and is spaced from the piezoelectric structure 2. The piezoelectric structure 2 is fixedly connected to the package base 12, which can facilitate the installation and fixation of the piezoelectric structure 2. Optionally, the package shell 11 is a cylindrical structure, one end of which is connected to the outer side of the package base 12, so that a receiving space 101 is enclosed between the package shell 11 and the package base 12.

[0071] Furthermore, the package housing 11 may be adhered to the package base 12 , or fixedly connected to the package base 12 by threads, or fixedly connected to the package base 12 by welding, or may also be fixedly connected to the package base 12 by other acceptable methods.

[0072] In this embodiment, refer to Figures 6 to 9 Looking down at the piezoelectric actuator along the first direction, the packaging shell 11 has a circular ring profile or a rectangular ring profile, and the piezoelectric structure 2 has a circular profile or a rectangular profile, that is, the cross-section of the packaging shell 11 along the cross-section perpendicular to the first direction is a circular ring structure or a rectangular ring structure, and the cross-section of the piezoelectric structure 2 along the cross-section perpendicular to the first direction is a circular structure or a rectangular structure.

[0073] In an alternative embodiment, reference Figure 6 Looking down at the piezoelectric actuator along the first direction, for example, the packaging shell 11 has a circular ring profile, and the piezoelectric structure 2 has a rectangular profile, that is, the cross section of the packaging shell 11 along the first direction perpendicular to the first direction is a circular ring structure, and the cross section of the piezoelectric structure 2 along the first direction perpendicular to the first direction is a rectangular structure.

[0074] In an alternative embodiment, reference Figure 7, looking down at the piezoelectric actuator along the first direction, for example, the packaging shell 11 has a rectangular ring profile, and the piezoelectric structure 2 has a circular profile, that is, the cross-section of the packaging shell 11 along the first direction perpendicular to the first direction is a rectangular ring structure, and the cross-section of the piezoelectric structure 2 along the first direction perpendicular to the first direction is a circular structure.

[0075] In an alternative embodiment, reference Figure 8 , looking down at the piezoelectric actuator along the first direction, for example, the package shell 11 has a rectangular ring-shaped profile, and the piezoelectric structure 2 has a rectangular profile, that is, the cross section of the package shell 11 along the first direction perpendicular to the first direction is a rectangular ring-shaped structure, and the cross section of the piezoelectric structure 2 along the first direction perpendicular to the first direction is a rectangular structure. In practical applications, some specific scenarios require the use of a rectangular shell. When the package shell 11 with a rectangular profile and the piezoelectric structure 2 with a rectangular profile are used, the thickness of the filling package layer 4 is made consistent, thereby making the force acting on the piezoelectric structure 2 more evenly distributed.

[0076] In an alternative embodiment, reference Fig. 9 , looking down at the piezoelectric actuator along the first direction, for example, the package shell 11 has a circular ring profile, and the piezoelectric structure 2 has a circular profile, that is, the cross section of the package shell 11 along the first direction perpendicular to the first direction is a circular ring structure, and the cross section of the piezoelectric structure 2 along the first direction perpendicular to the first direction is a circular structure. When the package shell 11 with a circular profile and the piezoelectric structure 2 with a circular profile are used, compared with Figure 8 In addition to making the thickness of the filling packaging layer 4 uniform, the embodiment can also have a larger area and a more uniform force.

[0077] It should be noted that users can make the above combinations based on factors such as application scenarios, costs, and processes. There is no absolute optimal choice.

[0078] In an alternative embodiment, reference Figure 1 and Figure 3 The transmission output structure 5 includes a transmission base 52 and a transmission output member 51. The transmission base 52 is located between the transmission output member 51 and the piezoelectric structure 2, and the transmission output member 51 is connected to the surface of the transmission base 52 away from the piezoelectric structure 2. Optionally, when looking down at the piezoelectric actuator along the first direction, the outer contour of the transmission output member 51 is located within the outer contour of the transmission base 52, and the transmission output member 51 passes through the first opening 102 from the accommodating space 101 and extends to the outside of the accommodating space 101. The transmission output structure 5 can be an integrated structure or a discrete structure. Optionally, the transmission output structure 5 adopts an integrated structure, and the transmission base 52 contacts the piezoelectric structure 2. Further, the transmission base 52 abuts against the piezoelectric structure 2, and the transmission base 52 and the piezoelectric structure 2 are fixedly connected.

[0079] Further, the piezoelectric actuator further comprises a cover plate 61 and an elastic member 62; the cover plate 61 is arranged on a side of the transmission base 52 away from the piezoelectric structure 2 along the first direction, and is fixedly connected to the shell structure 1; the cover plate 61 and the shell structure 1 enclose a receiving space 101, and are spaced apart from the transmission base 52, thereby forming a movement space for the transmission base 52; a through hole 611 penetrating along the first direction is arranged in the cover plate 61, and the transmission output member 51 passes through the through hole 611 from the inside of the receiving space 101 and extends to the outside of the receiving space 101, and optionally, the transmission output member 51 It is spaced apart from the inner wall of the through hole 611; the elastic member 62 surrounds the outer periphery of the transmission output member 51 and is located between the cover plate 61 and the transmission base 52. The elastic member 62 can apply prestress to the transmission base 52, thereby allowing prestress to exist between the transmission output structure 5 and the piezoelectric structure 2, thereby ensuring that the transmission output structure 5 can move along the first direction to output the displacement of the piezoelectric structure 2 and reset it, thereby improving the structural stability and working reliability of the piezoelectric actuator. Optionally, the elastic member 62 can be, for example, an elastic gasket, a spring or other acceptable elastic member 62.

[0080] In an alternative embodiment, reference Fig.10 and Fig.11 The filling packaging layer 4 includes a plurality of filling segments 41. Preferably, the plurality of filling segments 41 are arranged uniformly and sequentially along the first direction. Optionally, the filling packaging layer 4 includes, for example, two filling segments 41, which are respectively recorded as a first filling segment and a second filling segment. For example, the first filling segment can surround the end of the piezoelectric structure 2 close to the first opening 102, and the second filling segment is located between the first filling segment 41 and the packaging base 12; or the filling packaging layer 4 includes, for example, three filling segments 41, which are uniformly and sequentially arranged along the first direction. By setting the filling packaging layer 4 as a plurality of uniformly spaced filling segments 41, the contact area between the filling packaging layer 4 and the protective layer 3 can be reduced while ensuring the protective effect of the filling packaging layer 4 on the piezoelectric structure 2, and the resistance of the piezoelectric actuator when it moves along the first direction can be further reduced.

[0081] In an alternative embodiment, reference Fig.12 The piezoelectric actuator further includes an isolation gasket 7, which is located between the transmission output structure 5 and the piezoelectric structure 2. Optionally, the isolation gasket 7 is fixedly connected to the piezoelectric structure 2 and is in sliding contact with the transmission output structure 5. The isolation gasket 7 is provided to achieve a decoupling effect between the normal stress along the first direction and the tangential stress perpendicular to the first direction on the transmission output structure 5, so that the piezoelectric structure 2 can be protected from the influence of the tangential force on the transmission output structure 5, thereby further reducing the risk of the piezoelectric structure 2 breaking when the piezoelectric actuator is subjected to a tangential impact, improving the protection effect on the piezoelectric structure 2, and helping to increase the service life of the piezoelectric actuator.

[0082] In summary, the piezoelectric actuator provided in the present application can support the travel surface of the piezoelectric structure 2 through the filling packaging layer 4, fully decompose the impact energy, and avoid damage to the piezoelectric structure 2 due to excessive local stress; the anti-sticking layer 31 of the protective layer 3 can avoid adhesion between the filling packaging layer 4 and the piezoelectric structure 2, which helps to reduce the movement resistance of the piezoelectric structure 2 and ensure the displacement output of the piezoelectric actuator; further, the protective layer 3 also includes an elastic packaging layer 32, which can avoid hard contact between the piezoelectric structure 2 and the filling packaging layer 4, reduce the constraints of the piezoelectric structure 2 in the displacement direction, and further ensure the stable output of the piezoelectric actuator; by setting the isolation gasket 7, the decoupling between the piezoelectric structure 2 and the transmission output structure 5 is achieved, the risk of breakage of the piezoelectric structure 2 is further reduced, and the service life of the piezoelectric actuator is improved. Therefore, compared with the prior art, the piezoelectric actuator of the present application can impose elastic constraints on the piezoelectric structure 2 when subjected to tangential impact or tangential stress, thereby effectively reducing or avoiding the risk of damage to the piezoelectric structure 2. At the same time, while ensuring the protection of the piezoelectric structure 2, the constraints on the output displacement of the piezoelectric structure 2 along the first direction are effectively reduced, the resistance during the operation of the piezoelectric actuator is reduced, the structural stability and reliability of the product are improved, and the applicability of the piezoelectric actuator is improved, so that it can adapt to a variety of complex application scenarios. The solution of the present application effectively overcomes the various defects in the prior art and has a high industrial application value.

[0083] Embodiment 2

[0084] This embodiment provides a packaging method for a piezoelectric actuator, which is used to package and form any of the piezoelectric actuators described in the first embodiment. Fig.13 The packaging method of the piezoelectric actuator provided in this embodiment includes steps S1 to S5, specifically including:

[0085] Step S1: providing a piezoelectric structure 2, a housing structure 1 and a transmission output structure 5, wherein a receiving space 101 is provided in the housing structure 1, and a first opening 102 is opened at one end of the receiving space 101;

[0086] Step S2: forming a protective layer 3 on the side of the piezoelectric structure 2;

[0087] Step S3: fixing the piezoelectric structure 2 to the bottom of the accommodation space 101;

[0088] Step S4: forming a filling packaging layer 4 between the protective layer 3 and the shell structure 1;

[0089] Step S5: installing the transmission output structure 5 to the first opening 102 of the housing structure 1 to output the displacement of the piezoelectric structure 2 along the first direction.

[0090] The packaging method of the piezoelectric actuator 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 packaging method protected by this application, and those skilled in the art may change it according to the actual processing steps.

[0091] First, step S1 is performed to provide a piezoelectric structure 2 , a housing structure 1 and a transmission output structure 5 .

[0092] Specifically, a accommodating space 101 is provided in the shell structure 1 for installing and fixing the piezoelectric structure 2. A first opening 102 is provided at one end of the accommodating space 101. The first opening 102 is an installation positioning interface and a displacement output interface of the piezoelectric actuator. The piezoelectric structure 2 has a top surface and a bottom surface that are relatively arranged, and a side surface connecting the top surface and the bottom surface. The piezoelectric structure 2 includes a plurality of piezoelectric elements 21. The plurality of piezoelectric elements 21 are stacked in sequence, and the stacking direction of the plurality of piezoelectric elements 21 is taken as the first direction.

[0093] Then, step S2 is performed to form a protection layer 3 on the side surface of the piezoelectric structure 2 .

[0094] Specifically, refer to Fig.14 The protective layer 3 includes an anti-sticking layer 31. The anti-sticking material is coated on the side of the piezoelectric structure 2 to form the anti-sticking layer 31. Optionally, the anti-sticking material can be an oily material or a nano material. The thickness of the anti-sticking layer 31 formed by coating is less than 50 μm.

[0095] In an optional embodiment, an anti-sticking material may be coated on a portion of the side surfaces of the piezoelectric structure 2 to form a protective layer 3 , or an anti-sticking material may be coated on the entire side surfaces of the piezoelectric structure 2 to form an anti-sticking layer 31 .

[0096] Next, step S3 is performed to fix the piezoelectric structure 2 to the bottom of the accommodating space 101 .

[0097] Specifically, refer to Figure 2 , the bottom surface of the piezoelectric structure 2 can be fixedly connected to the bottom of the accommodating space 101 by bonding. Optionally, an adhesive material is applied to the bottom of the accommodating space 101, and the piezoelectric structure 2 is placed on the adhesive material so that the piezoelectric structure 2 is fixedly connected to the bottom of the accommodating space 101. Further, the piezoelectric structure 2 is connected to the central area of ​​the bottom of the accommodating space 101.

[0098] Next, step S4 is performed to form a filling packaging layer 4 between the protection layer 3 and the shell structure 1 .

[0099] Specifically, refer to Fig.15, filling material is injected between the protective layer 3 and the outer shell structure 1 to form a filling packaging layer 4. Optionally, the filling material may be, for example, a high-rigidity packaging glue, a composite material or other acceptable materials.

[0100] Finally, step S5 is performed to install the transmission output structure 5 to the first opening 102 of the housing structure 1 to output the displacement generated by the piezoelectric structure 2 along the first direction.

[0101] In an alternative embodiment, reference Fig.14 The protective layer 3 includes an anti-sticking layer 31 and an elastic packaging layer 32. Step S2 is performed to form the protective layer 3 on the side of the piezoelectric structure 2, including the following steps: forming the elastic packaging layer 32 on the side of the piezoelectric structure 2; forming the anti-sticking layer 31 on the surface of the elastic packaging layer 32, and making the anti-sticking layer 31 completely cover the elastic packaging layer 32.

[0102] Furthermore, an elastic material is coated on the surface of the piezoelectric structure 2 to form an elastic packaging layer 32, and the elastic packaging layer 32 covers at least a portion of the surface of the piezoelectric structure 2. The elastic material may be, for example, a polyurethane material, a rubber material, a graphite material or other acceptable materials, and the thickness of the elastic packaging layer 32 formed by coating is 10 μm to 1 mm.

[0103] In an optional embodiment, the shell structure 1 includes a packaging shell 11 and a packaging base 12, and step S3 is performed to fix the piezoelectric structure 2 to the bottom of the accommodating space 101, including the following steps: fixing the piezoelectric structure 2 to the packaging base 12; sleeve the packaging shell 11 on the periphery of the piezoelectric structure 2 and fixedly connect it to the packaging base 12.

[0104] Further, step S2 may be performed first, and then step S3; or, referring to Fig.16 and Figure 2 Alternatively, the piezoelectric structure 2 may be fixedly connected to the package base 12 before performing step S2 , where the package shell 11 is sleeved around the outer periphery of the piezoelectric structure 2 .

[0105] Furthermore, the packaging shell 11 and the packaging base 12 may be fixedly connected by bonding, or by welding, or by threads, or by other acceptable methods.

[0106] In an optional embodiment, the transmission output structure 5 includes a transmission base 52 and a transmission output member 51, and the piezoelectric further includes a cover plate 61 and an elastic member 62. After step S5, the following steps are further included: sleeve the elastic member 62 on the outer periphery of the transmission output member 51; sleeve the cover plate 61 on the outer periphery of the transmission output member 51, and press the elastic member 62 in a direction close to the transmission base 52 so that the elastic member 62 abuts against the transmission base 52; and fix the cover plate 61 to the shell structure 1. Optionally, the cover plate 61 is fixedly connected to the shell structure 1 by welding.

[0107] Furthermore, before performing step S5, the following step is also included: coating an adhesive material on the top surface of the piezoelectric structure 2. Based on the above operation, the transmission output structure 5 and the piezoelectric structure 2 can be fixedly connected.

[0108] Further, refer to Fig.10 The piezoelectric actuator also includes an isolation gasket 7, and before performing step S5, the following steps are also included: applying an adhesive material on the top surface of the piezoelectric structure 2; installing the isolation gasket 7 on the top surface of the piezoelectric structure 2 to ensure a fixed connection between the isolation gasket 7 and the piezoelectric structure 2.

[0109] In an alternative embodiment, reference Fig.11 and Fig.12 The filling packaging layer 4 includes a plurality of filling segments 41 , and a plurality of filling segments 41 are sequentially formed between the protection layer 3 and the shell structure 1 and spaced apart along the first direction to form the filling packaging layer 4 .

[0110] This embodiment provides a packaging method for a piezoelectric actuator, which is used to package and form any piezoelectric actuator described in the first embodiment, and thus has the same beneficial effects as the first embodiment.

[0111] 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 actuator, characterized in that: include: A shell structure (1) having a receiving space (101) disposed therein, wherein a first opening (102) is provided at one end of the receiving space (101); A piezoelectric structure (2) is located in the accommodating space (101), and has a top surface and a bottom surface that are arranged opposite to each other, and a side surface connecting the top surface and the bottom surface; the bottom surface of the piezoelectric structure (2) is connected to the bottom of the accommodating space (101) away from the first opening (102); the piezoelectric structure (2) comprises a plurality of piezoelectric elements (21); the plurality of piezoelectric elements (21) are stacked and arranged in sequence from the bottom of the accommodating space (101) toward the first opening (102); the stacking direction of the plurality of piezoelectric elements (21) is a first direction; A protective layer (3), located between the housing structure (1) and the piezoelectric structure (2), comprising an anti-adhesive layer (31), wherein the anti-adhesive layer (31) at least covers a portion of a side surface of the piezoelectric structure (2); A filling packaging layer (4) is located between the protective layer (3) and the shell structure (1), covers at least a portion of the protective layer (3), and is spaced apart from the piezoelectric structure (2); a transmission output structure (5), located on a side of the piezoelectric structure (2) close to the first opening (102), and used for outputting a displacement generated by the piezoelectric structure (2) along the first direction, the transmission output structure (5) comprising a transmission base (52) and a transmission output member (51), the transmission output member (51) being connected to a surface of the transmission base (52) on a side away from the piezoelectric structure (2); wherein, when the piezoelectric actuator is viewed from above along the first direction, an outer contour line of the transmission output member (51) is located within an outer contour line of the transmission base (52); an isolation gasket (7), the isolation gasket (7) being located between the transmission output structure (5) and the piezoelectric structure (2), being fixedly connected to the piezoelectric structure (2), and being in sliding contact with the transmission output structure (5); a cover plate (61) arranged at intervals along the first direction on a side of the transmission base (52) away from the piezoelectric structure (2), and fixedly connected to the housing structure (1), the cover plate (61) having a through hole (611) extending along the first direction, and the transmission output member (51) passing through the through hole (611); An elastic member (62) surrounds the outer side of the transmission output member (51) and is located between the cover plate (61) and the transmission base (52), and is used to provide prestress between the transmission output structure (5) and the piezoelectric structure (2).

2. The piezoelectric actuator according to claim 1, characterized in that: The protective layer (3) further comprises an elastic packaging layer (32), which is located between the anti-adhesion layer (31) and the piezoelectric structure (2) and is spaced apart from the filling packaging layer (4); the elastic packaging layer (32) at least covers part of the side surface of the piezoelectric structure (2).

3. The piezoelectric actuator according to claim 1, characterized in that: The filling encapsulation layer (4) comprises a plurality of filling segments (41), and the plurality of filling segments (41) are sequentially arranged at intervals along the first direction.

4. The piezoelectric actuator according to claim 1, characterized in that: The shell structure (1) comprises a packaging shell (11) and a packaging base (12); the bottom surface of the piezoelectric structure (2) is connected to the packaging base (12); the first opening (102) is arranged at one end of the packaging shell (11); an end of the packaging shell (11) away from the first opening (102) is connected to the packaging base (12), so that the packaging shell (11) is sleeved on the outer periphery of the packaging base (12) and the piezoelectric structure (2), and the packaging shell (11) and the piezoelectric structure (2) are spaced apart.

5. The piezoelectric actuator according to claim 4, characterized in that: Looking down at the piezoelectric actuator along the first direction, the packaging shell (11) has a circular ring profile or a rectangular ring profile, and the piezoelectric structure (2) has a circular profile or a rectangular profile.

6. A method for packaging a piezoelectric actuator, used for packaging the piezoelectric actuator according to any one of claims 1 to 5, characterized in that: The following steps are involved: A piezoelectric structure (2), a shell structure (1), an isolation gasket (7) and a transmission output structure (5) are provided, wherein a receiving space (101) is provided in the shell structure (1), and a first opening (102) is provided at one end of the receiving space (101); forming a protective layer (3) on the side surface of the piezoelectric structure (2); The piezoelectric structure (2) is fixedly connected to the bottom of the accommodating space (101); forming a filling packaging layer (4) between the protective layer (3) and the outer shell structure (1); Coating an adhesive material on the top surface of the piezoelectric structure (2), and installing the isolation gasket (7) on the top surface of the piezoelectric structure (2) so that the isolation gasket (7) and the piezoelectric structure (2) are fixedly connected; The transmission output structure (5) is mounted on the first opening (102) of the housing structure (1) to output the displacement generated by the piezoelectric structure along a first direction, wherein the transmission output structure (5) comprises a transmission output member (51) and a transmission base (52); The elastic member (62) is sleeved on the outer circumference of the transmission output member (51); The cover plate (61) is sleeved on the outer periphery of the transmission output member (51), and the elastic member (62) is pressed downward in a direction close to the transmission base (52), so that the elastic member (62) abuts against the transmission base (52); The cover plate (61) is fixedly connected to the housing structure (1).

7. The packaging method of a piezoelectric actuator according to claim 6, characterized in that: The protective layer (3) comprises an anti-adhesive layer (31) and an elastic packaging layer (32), and the step of forming the protective layer (3) on the side surface of the piezoelectric structure (2) comprises the following steps: forming an elastic packaging layer (32) on the side of the piezoelectric structure (2); The anti-sticking layer (31) is formed on the surface of the elastic packaging layer (32), and the anti-sticking layer (31) completely covers the elastic packaging layer (32).

8. The packaging method of a piezoelectric actuator according to claim 6, characterized in that: The housing structure (1) comprises a packaging housing (11) and a packaging base (12), and the process of fixedly connecting the piezoelectric structure (2) to the bottom of the accommodating space (101) comprises the following steps: Fixedly connecting the piezoelectric structure (2) to the packaging base (12); The packaging shell (11) is sleeved on the outer periphery of the piezoelectric structure (2) and fixedly connected to the packaging base (12).

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