Piezoelectric actuator

Abstract

The utility model discloses a piezoelectric actuator comprising an elastic tube, two ends of which are respectively provided with a first port and a second port; the first sealing piece is arranged at one end of the elastic pipe and seals the first port; the second sealing piece is arranged at the other end of the elastic pipe and seals the second port, and a sealed cavity is defined by the elastic pipe, the first sealing piece and the second sealing piece; the stack piezoelectric ceramic is arranged in the closed cavity, the two ends of the stack piezoelectric ceramic are connected with the first closed part and the second closed part respectively, and the elastic pipe is always in a stretched state; one of the first sealing piece and the second sealing piece is provided with a wire for electrically connecting the stacked piezoelectric ceramic with an external power supply, and the other one is provided with an actuating end for applying pressure to the outside. According to the application, the elastic tube can be driven to deform along with the deformation of the stacked piezoelectric ceramic by utilizing the characteristic that the elastic tube can be telescopically deformed. Therefore, an existing shaft hole matching structure can be omitted, and the negative influence of the friction effect on the output linearity of the stacked piezoelectric ceramic is avoided.

Description

Technical Field

[0001] This application relates to the field of precision drive technology, specifically to a piezoelectric actuator. Background Technology

[0002] Piezoelectric actuators, as core components that utilize the inverse piezoelectric effect of piezoelectric materials to convert electrical energy into mechanical energy, have wide applications in precision instruments, aerospace, and biomedicine. Existing piezoelectric actuators generally consist of a stacked piezoelectric ceramic housed within an encapsulated structure and an actuation shaft extending from the encapsulated structure. The portion of the actuation shaft within the encapsulated structure is fixed or abuts against the stacked piezoelectric ceramic. When the stacked piezoelectric ceramic is energized and deformed, it can push the actuation shaft outward, thereby applying force to external components and achieving the purpose of converting electrical energy into mechanical energy.

[0003] Existing piezoelectric actuators require a drive shaft that extends and retracts relative to its external packaging structure. This necessitates a connecting hole in the packaging structure to accommodate the drive shaft. Even with bearings and seals, the sliding fit between the drive shaft and the connecting hole affects the sealing performance of the packaging structure and negatively impacts the output linearity of the stacked piezoelectric ceramics. Furthermore, the friction between the drive shaft and the connecting hole intensifies with wear over time, causing the impact of this friction on the output linearity of the stacked piezoelectric ceramics to vary. Therefore, it is difficult to compensate for the negative impact of friction on the output linearity of the stacked piezoelectric ceramics using algorithms. Utility Model Content

[0004] This application aims to address one of the technical problems in the related art to a certain extent. To this end, this application provides a piezoelectric actuator.

[0005] To achieve the above objectives, this application adopts the following technical solution: a piezoelectric actuator, comprising:

[0006] An elastic tube, which has a first port and a second port at its two ends respectively;

[0007] A first closure element is disposed at one end of the elastic tube and closes the first port;

[0008] A second sealing member is disposed at the other end of the elastic tube and closes the second port; the elastic tube, the first sealing member, and the second sealing member together form a closed cavity; and...

[0009] A stacked piezoelectric ceramic is disposed within the enclosed cavity. Both ends of the stacked piezoelectric ceramic are connected to a first sealing member and a second sealing member, respectively. The elastic tube is always in a stretched state to apply a preload force to the stacked piezoelectric ceramic through the first and second sealing members.

[0010] The first and second enclosures are provided with a wire that connects the stacked piezoelectric ceramic to an external power source, and the other enclosure is provided with an actuation end for applying pressure to the outside.

[0011] The application of this application has the following beneficial effects: a closed cavity is formed by an elastic tube, a first sealing member, and a second sealing member, and the stacked piezoelectric ceramic is placed inside the closed cavity. Utilizing the expandable and deformable characteristics of the elastic tube, when the stacked piezoelectric ceramic deforms, the elastic tube can be driven to deform accordingly, while the actuating end applies a force to the outside. This structural design eliminates the shaft-hole mating structure of the prior art, avoiding the negative impact of friction on the output linearity of the stacked piezoelectric ceramic. Therefore, not only can good sealing performance be achieved for the stacked piezoelectric ceramic, but the control accuracy of the piezoelectric actuator can also be improved.

[0012] Optionally, one end of the stacked piezoelectric ceramic is fixed to the first enclosure, the other end of the stacked piezoelectric ceramic abuts against the second enclosure, the wire is disposed in the first enclosure, and the actuating end is located in the second enclosure.

[0013] Optionally, the first closure includes a sealing cap and a sealing filler, the sealing cap having a lead hole for the wire to pass through, and the sealing filler sealing the lead hole.

[0014] Optionally, the sealing cover includes a cover plate and an annular connecting portion located on the cover plate. The sealing cover is fixedly connected to the elastic tube through the annular connecting portion. The cover plate and the annular connecting portion cooperate to form a connecting groove. One end of the stacked piezoelectric ceramic is clamped and fixed in the connecting groove.

[0015] Optionally, the annular connecting part is fixed by welding, bonding, or threading to the elastic tube.

[0016] Optionally, the second closure includes a connecting tube and a sealing cap threaded into the connecting tube. The connecting tube is fixed to the elastic tube. The sealing cap abuts against the stacked piezoelectric ceramic at one end face facing the stacked piezoelectric ceramic, and the sealing cap has the actuating end at the other end face facing away from the stacked piezoelectric ceramic.

[0017] Optionally, the end face of the stacked piezoelectric ceramic facing the sealing cap is a plane, and the end face of the sealing cap facing the stacked piezoelectric ceramic is a plane or a spherical cap.

[0018] Optionally, the connecting pipe is fixed to the elastic pipe by welding, bonding, or threading.

[0019] Optionally, there is a gap between the stacked piezoelectric ceramic and the inner wall surface of the elastic tube.

[0020] Optionally, the elastic tube is a corrugated tube.

[0021] These features and advantages of this application will be disclosed in detail in the following specific embodiments and accompanying drawings. The best embodiments or means of this application will be shown in detail in conjunction with the accompanying drawings, but are not intended to limit the technical solutions of this application. In addition, each of these features, elements and components appearing in the following text and drawings is multiple and is labeled with different symbols or numbers for convenience, but all represent parts with the same or similar structure or function. Attached Figure Description

[0022] The following description, in conjunction with the accompanying drawings, further illustrates this application:

[0023] Figure 1 This is a schematic diagram of the structure of a piezoelectric actuator provided in an embodiment of this application;

[0024] Figure 2 This is an exploded view of a piezoelectric actuator.

[0025] Figure 3 An exploded view of a piezoelectric actuator from another perspective;

[0026] Figure 4 This is a cross-sectional view of a piezoelectric actuator.

[0027] Among them, 1. elastic tube; 10. first port; 11. second port; 2. first closure; 20. sealing cap; 200. cover plate; 2000. lead hole; 201. annular connection part; 202. connecting groove; 3. second closure; 30. connecting tube; 31. sealing cap; 310. actuation end; 4. stacked piezoelectric ceramic. Detailed Implementation

[0028] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described are intended to explain this application and should not be construed as limiting it.

[0029] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "connected," "linked," and "connected" should be interpreted broadly. For example, they can refer to a fixed connection, a connection through an intermediary, or a connection within two elements or an interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0030] This embodiment provides a piezoelectric actuator, such as Figure 1 , Figure 2 , Figure 3 and Figure 4As shown, the piezoelectric actuator includes an elastic tube 1, a first sealing member 2, a second sealing member 3, and a stacked piezoelectric ceramic 4. The elastic tube 1 has a first port 10 and a second port 11 at its two ends. The first sealing member 2 is located at one end of the elastic tube 1 and closes the first port 10, while the second sealing member 3 is located at the other end of the elastic tube 1 and closes the second port 11. The elastic tube 1, the first sealing member 2, and the second sealing member 3 cooperate to form a closed cavity, within which the stacked piezoelectric ceramic 4 is disposed. This structural design achieves encapsulation of the stacked piezoelectric ceramic 4 with excellent sealing performance, preventing dust, acidic gases, and humid environments from negatively impacting its performance.

[0031] Meanwhile, both ends of the stacked piezoelectric ceramic 4 are connected to the first sealing member 2 and the second sealing member 3, respectively. Specifically, one end of the stacked piezoelectric ceramic 4 is fixed to the first sealing member 2, and the other end of the stacked piezoelectric ceramic 4 abuts against the second sealing member 3. The elastic tube 1 is always in a stretched state to apply a preload force to the stacked piezoelectric ceramic 4 through the first sealing member 2 and the second sealing member 3. The first sealing member 2 is provided with a wire that electrically connects the stacked piezoelectric ceramic 4 to an external power source, and the second sealing member 3 is provided with an actuating end 310 for applying pressure to the outside. The piezoelectric actuator provided in this embodiment can utilize the stretchable and deformable characteristics of the elastic tube 1. When the stacked piezoelectric ceramic 4 deforms, it can drive the elastic tube 1 to deform accordingly, while applying force to the outside using the actuating end 310. Through the above structural design, the shaft-hole mating structure in the prior art can be eliminated, avoiding the negative impact of friction on the output linearity of the stacked piezoelectric ceramic 4. This not only achieves good sealing performance for the stacked piezoelectric ceramic 4 but also improves the control accuracy of the piezoelectric actuator.

[0032] It should be noted that, in other optional embodiments, the two ends of the stacked piezoelectric ceramic 4 can be abutted against the first sealing member 2 and the second sealing member 3 respectively. In this way, the first sealing member 2 and the second sealing member 3 can also apply a preload force to the stacked piezoelectric ceramic 4 from both ends under the stretching action of the elastic tube 1. In addition, in other optional embodiments, the wire can also be set on the second sealing member 3, and correspondingly, the actuating end 310 can also be located on the first sealing member 2.

[0033] In this embodiment, the elastic tube 1 is a corrugated tube. In other optional embodiments, the elastic tube 1 can also be an elastic tube made of elastic materials such as natural rubber, silicone rubber, and polyurethane.

[0034] like Figure 2As shown, the first sealing element in this embodiment includes a sealing cap 20 and a sealing filler (not shown in the figure). The sealing cap 20 is provided with a lead hole 2000 for a wire to pass through, and the sealing filler is used to seal the lead hole 2000. It is readily understood that during assembly, the wire is first led out from the sealing cavity through the lead hole 2000 to the outside, and then the lead hole 2000 is sealed by the sealing filler. The sealing filler can be a sealing structure made of materials such as epoxy resin, silicone rubber, polyurethane, or hot melt adhesive.

[0035] Furthermore, in this embodiment, the sealing cap 20 includes a cover plate 200 and an annular connecting portion 201 located on the cover plate 200. The sealing cap 20 is fixedly connected to the elastic tube 1 via the annular connecting portion 201. Specifically, in this embodiment, both the elastic tube 1 and the sealing cap 20 are made of metal, and the annular connecting portion 201 is fixedly connected to the elastic tube 1 by laser welding. In other optional embodiments, adhesive or threaded connections can also be used to fix the annular connecting portion 201 to the elastic tube 1. Additionally, as... Figure 3 As shown, in this embodiment, the cover plate 200 and the annular connecting part 201 cooperate to form a connecting groove 202, and one end of the stacked piezoelectric ceramic 4 is inserted and fixed in the connecting groove 202 by interference fit.

[0036] In this embodiment, the second sealing member 3 includes a connecting pipe 30 and a sealing cap 31 threadedly connected to the connecting pipe 30. The connecting pipe 30 is fixedly connected to the elastic tube 1. The end face of the sealing cap 31 facing the stacked piezoelectric ceramic 4 abuts against the stacked piezoelectric ceramic 4, and the end face of the sealing cap 31 facing away from the stacked piezoelectric ceramic 4 is provided with an actuating end 310. In this embodiment, the connecting pipe 30 and the sealing cap 31 are also made of metal, and the connecting pipe 30 is also fixedly connected to the elastic tube 1 by laser welding. Similarly, in other optional embodiments, the connecting pipe 30 and the elastic tube 1 can also be fixedly connected by adhesive bonding or threaded connection.

[0037] Through the above structural design, the sealing cap 31 can be screwed relative to the connecting pipe 30. During the screwing process, the distance between the sealing cap 31 and the sealing cover 20 changes, which in turn changes the preload applied to the stacked piezoelectric ceramic 4 by the first sealing member 2 and the second sealing member 3, thus adjusting the preload. The stacked piezoelectric ceramic 4 is composed of multiple layers of piezoelectric ceramic sheets, and applying a preload is crucial for its normal operation. Simultaneously, a suitable preload ensures tight contact between the piezoelectric ceramic sheets, reducing interlayer gaps and contact resistance, making the piezoelectric effect more stable, and thereby improving the displacement accuracy and output pressure accuracy of the piezoelectric actuator. Furthermore, applying a preload to the stacked piezoelectric ceramic 4 prevents relative slippage of the piezoelectric ceramic sheets in applications involving high-frequency vibration and alternating electric fields, thereby avoiding mechanical wear and fatigue damage.

[0038] The piezoelectric actuator provided in this embodiment can cause the stacked piezoelectric ceramic 4 to deform by 0-10 μm by screwing the sealing cap 31. In the unenergized state, the magnitude of the preload applied to the stacked piezoelectric ceramic 4 can be changed by applying pressure to change its deformation. Alternatively, a pressure sensor can be installed inside the sealed cavity, positioned between the stacked piezoelectric ceramic 4 and the sealing cap 31. The pressure sensor can directly detect the magnitude of the preload applied to the stacked piezoelectric ceramic.

[0039] It should be noted that the elastic tube 1, connecting tube 30, and sealing cap 20 can also be made of non-metallic materials. For example, as mentioned above, the elastic tube 1 can be an elastic tube made of natural rubber, silicone rubber, polyurethane, etc. In this case, the elastic tube 1 can be fixed to the connecting tube 30 and sealing cap 20 by adhesive bonding. The connecting tube 30 and sealing cap 20 can also be made of plastic.

[0040] Combination Figure 2 and Figure 4 As shown, in this embodiment, the end face of the stacked piezoelectric ceramic 4 facing the sealing cap 31 is a plane, and the end face of the sealing cap 31 facing the stacked piezoelectric ceramic 4 is also a plane. That is, in this embodiment, the planes of the sealing cap 31 and the stacked piezoelectric ceramic 4 are in contact. In other optional embodiments, the end face of the sealing cap 31 facing the stacked piezoelectric ceramic 4 can also be designed as a spherical cap. This design can reduce the contact area between the sealing cap 31 and the stacked piezoelectric ceramic 4, thereby reducing wear between the sealing cap 31 and the stacked piezoelectric ceramic 4 during the tightening of the sealing cap 31, and also making it easier to maintain the alignment of the stacked piezoelectric ceramic 4 with respect to the elastic tube 1.

[0041] The piezoelectric actuator provided in this embodiment eliminates the shaft hole design found in the prior art, thereby avoiding the negative impact of friction on the output linearity of the stacked piezoelectric ceramic 4. To further reduce friction between components in the piezoelectric actuator, such as... Figure 2 , Figure 3 and Figure 4 As shown, in this embodiment, the stacked piezoelectric ceramic 4 and the inner wall of the elastic tube 1 are designed to have a gap, so that the stacked piezoelectric ceramic 4 will not rub against the inner wall of the elastic tube 1 during the deformation process.

[0042] In this embodiment, the piezoelectric actuator is assembled by first passing the lead wires from the stacked piezoelectric ceramic 4 through the lead hole 2000 on the sealing cover 20, and then inserting the stacked piezoelectric ceramic 4 into the connecting groove 202 of the sealing cover 20 using an interference fit. Next, the stacked piezoelectric ceramic 4 is inserted into the elastic tube 1 through the first port 10, and then the annular connecting part 201 and the connecting tube 30 are fixed to both ends of the elastic tube 1 using laser welding. Finally, the sealing cap 31 is screwed onto the connecting tube 30, and the sealing cap 31 is screwed to a suitable position according to the application scenario to apply a suitable preload force to the stacked piezoelectric ceramic 4.

[0043] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Those skilled in the art should understand that this application includes, but is not limited to, the contents described in the accompanying drawings and the specific embodiments above. Any modifications that do not depart from the functional and structural principles of this application will be included within the scope of the claims.

Claims

1. A piezoelectric actuator, characterized in that, include: The elastic tube (1) has a first port (10) and a second port (11) at both ends; The first closure member (2) is disposed at one end of the elastic tube (1) and closes the first port (10); The second sealing member (3) is disposed at the other end of the elastic tube (1) and closes the second port (11). The elastic tube (1), the first sealing member (2) and the second sealing member (3) together form a closed cavity. as well as, Stacked piezoelectric ceramics (4) are disposed in the enclosed cavity. The two ends of the stacked piezoelectric ceramics (4) are respectively connected to the first sealing member (2) and the second sealing member (3). The elastic tube (1) is always in a stretched state so as to apply a preload force to the stacked piezoelectric ceramics (4) through the first sealing member (2) and the second sealing member (3). The first enclosure (2) and the second enclosure (3) are provided with a wire that connects the stacked piezoelectric ceramic (4) to an external power source, and the other is provided with an actuation end (310) for applying pressure to the outside.

2. The piezoelectric actuator as described in claim 1, characterized in that, One end of the stacked piezoelectric ceramic (4) is fixed to the first enclosure (2), the other end of the stacked piezoelectric ceramic (4) abuts against the second enclosure (3), the wire is disposed in the first enclosure (2), and the actuating end (310) is located in the second enclosure (3).

3. The piezoelectric actuator as described in claim 2, characterized in that, The first closure (2) includes a sealing cap (20) and a sealing filler, the sealing cap (20) being provided with a lead hole (2000) for the wire to pass through, and the sealing filler being used to seal the lead hole (2000).

4. The piezoelectric actuator as described in claim 3, characterized in that, The sealing cover (20) includes a cover plate (200) and an annular connecting part (201) located on the cover plate (200). The sealing cover (20) is fixed to the elastic tube (1) through the annular connecting part (201). The cover plate (200) and the annular connecting part (201) cooperate to form a connecting groove (202). One end of the stacked piezoelectric ceramic (4) is clamped and fixed in the connecting groove (202).

5. The piezoelectric actuator as described in claim 4, characterized in that, The annular connecting part (201) is fixed to the elastic tube (1) by welding, bonding, or threading.

6. The piezoelectric actuator as described in claim 2, characterized in that, The second sealing member (3) includes a connecting tube (30) and a sealing cap (31) threaded into the connecting tube (30). The connecting tube (30) is fixed to the elastic tube (1). The sealing cap (31) abuts against the stacked piezoelectric ceramic (4) at one end face facing the stacked piezoelectric ceramic (4). The sealing cap (31) is provided with the actuating end (310) at one end face away from the stacked piezoelectric ceramic (4).

7. The piezoelectric actuator as claimed in claim 6, characterized in that, The end face of the stacked piezoelectric ceramic (4) facing the sealing cap (31) is a plane, and the end face of the sealing cap (31) facing the stacked piezoelectric ceramic (4) is a plane or a spherical cap.

8. The piezoelectric actuator as described in claim 6, characterized in that, The connecting pipe (30) is fixed to the elastic pipe (1) by welding, bonding, or threading.

9. The piezoelectric actuator as described in any one of claims 1 to 8, characterized in that, There is a gap between the stacked piezoelectric ceramic (4) and the inner wall surface of the elastic tube (1).

10. The piezoelectric actuator as claimed in any one of claims 1 to 8, characterized in that, The elastic tube (1) is a wave-shaped tube.

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