Torsion-resistant piezoelectric actuator

Abstract

The invention relates to the technical field of precision motion, and discloses an anti-torsion piezoelectric actuator which comprises a shell, a table top, piezoelectric ceramics and an output structure. A first cavity is formed in the shell. A second cavity is defined by the table top and the shell. The piezoelectric ceramic is arranged in the first cavity and extends to the second cavity. The output structure comprises a push rod and a flexible hinge mechanism. The flexible hinge mechanism comprises four flexible hinges. The four flexible hinges are of a cross-shaped symmetrical structure. The flexible hinge is arranged in the second cavity and connected with the shell. And the push rod is coaxially connected with the piezoelectric ceramic. The top of the push rod penetrates through the tabletop. The integrated design of the push rod and the flexible hinge mechanism is adopted, and the cross-shaped symmetrical structure is adopted, so that it is guaranteed that the push rod is prevented from shaking and shifting, and the repeated positioning precision is improved; 2, the torsion generated by external machinery is eliminated, the piezoelectric ceramic is prevented from being damaged, and the stability of the product is improved; meanwhile, strain sensor closed-loop control is adopted, repeated positioning precision is greatly improved, and the method is suitable for dynamic application scenes.

Description

Technical Field

[0001] This invention belongs to the field of precision motion technology, and more specifically, relates to an anti-torsion piezoelectric actuator. Background Technology

[0002] Piezoelectric actuators convert electrical energy into mechanical energy for high-precision displacement adjustment and are widely used in optics, precision instruments, and many other fields. Their high-strength shell structure provides effective protection. Facing complex operating environments, multi-layered stacked piezoelectric ceramics, with their characteristics of fast response, low driving voltage, high displacement linearity, and large output force, can serve as the power source for actuators. Actuators using piezoelectric ceramics as their core are formed by integrating the piezoelectric ceramic body with a rigid shell. However, the internal structure of the piezoelectric ceramic is easily damaged when subjected to external forces such as tension, torque, and shear force. Problems with existing technology include: 1. When the output end of the piezoelectric actuator is connected to the load, even a slight rotation at the output end can subject the stacked piezoelectric ceramic to rotational torque, easily damaging the piezoelectric ceramic and resulting in poor product operational stability; 2. Temperature changes affect the performance of the piezoelectric ceramic; 3. Poor repeatability and positioning accuracy.

[0003] Based on the above, the current problem to be solved is to provide a torsional piezoelectric actuator with high repeatability and stable operation. Summary of the Invention

[0004] The purpose of this invention is to provide an anti-torsion piezoelectric actuator, which aims to solve the problems in the prior art where piezoelectric actuators are easily damaged by lateral forces and torque, have low repositioning accuracy, and are unstable in operation.

[0005] This invention is implemented as follows: an anti-torsion piezoelectric actuator, comprising:

[0006] The outer shell has a first cavity inside it;

[0007] A tabletop is provided on the outer shell, and a second cavity is formed between the tabletop and the outer shell;

[0008] A piezoelectric ceramic is disposed in the first cavity and extends through the first cavity to the second cavity;

[0009] The output structure includes a push rod and a flexible hinge mechanism connected to the push rod. The flexible hinge mechanism includes four flexible hinges arranged in a cross-shaped symmetrical structure. The flexible hinges are located in the second cavity and connected to the outer shell. The bottom of the push rod is coaxially connected to the piezoelectric ceramic, and the top of the push rod penetrates the platform.

[0010] Furthermore, the push rod is fitted with a first washer, a butterfly spring, and a locking nut from bottom to top. The first washer, the butterfly spring, and the locking nut are pressed together in sequence, and the side wall of the locking nut is threadedly connected to the table surface.

[0011] Furthermore, the piezoelectric ceramic is connected to the push rod via a second washer.

[0012] Furthermore, the end face of the locking nut is provided with a clamping hole.

[0013] Furthermore, the flexible hinge includes two parallel straight beam hinge arms.

[0014] Furthermore, a strain sensor is provided on the flexible hinge.

[0015] Furthermore, the outer casing is provided with an air-cooling connection port.

[0016] Furthermore, an adhesive layer is provided between the end of the first cavity and the piezoelectric ceramic for sealing.

[0017] Furthermore, the bottom of the housing is provided with a base, the bottom of the piezoelectric ceramic is connected to the base, and an adhesive layer is provided between the housing and the base for sealing.

[0018] Furthermore, the housing is provided with mounting holes for connection to external mechanisms.

[0019] The advantages of the anti-torsion piezoelectric actuator provided by this invention are as follows:

[0020] I. The output structure of this invention adopts an integrated design of push rod and flexible hinge mechanism. The flexible hinge mechanism is set as a cross-shaped symmetrical structure with anti-torsional force. This structure setting, on the one hand, enables the push rod to have the effect of anti-vibration and anti-misalignment, so that the repeatability and positioning accuracy of the output structure is high; on the other hand, it can effectively resist the torque during the load reinforcement process of push rod installation, avoiding damage to the internal piezoelectric ceramic due to torsional force, greatly improving product stability and extending product service life.

[0021] Second, each flexible hinge includes two parallel straight beam hinge arms. This structure effectively eliminates the torque generated by external machinery, preventing damage to the piezoelectric ceramic and improving the anti-vibration effect. The invention has a compact structure and is very easy to integrate.

[0022] Third, the present invention is equipped with an air-cooling connection port, which facilitates connection with air-cooling equipment, reduces the impact of temperature on the performance of piezoelectric ceramics, and greatly improves positioning accuracy.

[0023] Fourth, this invention uses a strain sensor to detect and provide feedback on position in real time, which can eliminate the hysteresis and creep characteristics of piezoelectric ceramics. The closed-loop feedback control greatly improves the repeatability of positioning accuracy and realizes nanometer-level precision control, which is suitable for dynamic application scenarios. Attached Figure Description

[0024] Figure 1 This is a three-dimensional structural schematic diagram of the anti-torsion piezoelectric actuator provided in Embodiment 1 of the present invention;

[0025] Figure 2 This is a cross-sectional view of the anti-torsion piezoelectric actuator of Embodiment 1 provided by the present invention;

[0026] Figure 3 This invention provides Figure 2 A magnified view of a portion of the image;

[0027] Figure 4 Exploded view of the anti-torsion piezoelectric actuator of Embodiment 1 provided by the present invention;

[0028] Figure 5 This is a three-dimensional structural diagram of the output structure provided by the present invention;

[0029] Figure 6 This is a three-dimensional structural schematic diagram of the anti-torsion piezoelectric actuator of Embodiment 2 provided by the present invention;

[0030] Figure 7 This is a three-dimensional structural schematic diagram of the anti-torsion piezoelectric actuator of Embodiment 3 provided by the present invention;

[0031] In the figure: 1-outer shell; 101-first cavity; 102-air-cooled connection port; 103-mounting hole; a-first housing; b-second housing; 2-tabletop; 201-second cavity; 3-piezoelectric ceramic; 4-output structure; 401-push rod; 402-flexible hinge mechanism; 4021-flexible hinge; 5-first washer; 6-butterfly spring; 7-locking nut; 701-clamping hole; 8-second washer; 9-strain sensor; 10-adhesive layer; 11-base. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0033] The implementation of the present invention will be described in detail below with reference to specific embodiments.

[0034] In the accompanying drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components. In the description of this invention, it should be understood that if terms such as "upper," "lower," "left," and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting this invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0035] Reference Figure 1-7 The image shown is a preferred embodiment of the present invention.

[0036] Example 1: The anti-torsion piezoelectric actuator includes a housing 1, a platform 2, a piezoelectric ceramic 3, an output structure 4, and a base 11, as shown in the figure. Figure 1 The outer shell 1 and the platform 2 are rectangular. The outer shell 1 has a first cavity 101, as shown in the figure. Figure 2-3 A platform 2 is mounted on the outer casing 1. The bottom of the platform 2 is bolted to the top of the outer casing 1. The platform 2 and the outer casing 1 form a second cavity 201. The bottom of the outer casing 1 is bolted to the base 11. A piezoelectric ceramic 3 is disposed within the first cavity 101 and extends through the first cavity 101 to the second cavity 201. The bottom of the piezoelectric ceramic 3 is connected to the base 11. An adhesive layer 10 is provided between the outer casing 1 and the base 11 for fixing and sealing. An adhesive layer 10 is provided between the end of the first cavity 101 and the piezoelectric ceramic 3 for fixing and sealing. The top of the piezoelectric ceramic 3 is connected to the output structure 4. Under the action of a driving voltage, the piezoelectric ceramic 3 can extend and retract, thereby pushing the output structure 4 connected to it to perform a one-dimensional linear motion.

[0037] Output structure 4 includes a push rod 401 and a flexible hinge mechanism 402 integrally formed with the push rod 401, as shown in the figure. Figure 4-5The push rod 401 is used to connect to the load and actuate the load slightly. The flexible hinge mechanism 402 deforms when the piezoelectric ceramic 3 extends or retracts. The flexible hinge mechanism 402 includes four flexible hinges 4021. The four flexible hinges 4021 are arranged in a cross-shaped symmetrical structure. Preferably, the flexible hinge mechanism 402 is approximately perpendicular to the push rod 401 in the non-deformed state. The flexible hinge mechanism 402 allows the push rod 401 to perform axial reciprocating linear motion and restricts the non-axial left-right jitter and torsion of the push rod 401. The flexible hinges 4021 are located within the second cavity 201. One end of the flexible hinge 4021 is connected to the push rod 401, and the end of the flexible hinge 4021 away from the push rod 401 is bolted to the housing 1. The bottom of the push rod 401 is coaxially connected to the piezoelectric ceramic 3. The cross-shaped symmetrical structure of the flexible hinge mechanism 402 can effectively resist the torsional force on the piezoelectric ceramic 3 during the installation load locking and reinforcement process, thereby avoiding damage to the piezoelectric ceramic 3. Preferably, the piezoelectric ceramic 3 and the push rod 401 are connected by a second washer 8. The second washer 8 can protect the end of the piezoelectric ceramic 3 from damage.

[0038] Furthermore, each flexible hinge 4021 includes two parallel straight beam hinge arms, as shown in the reference. Figure 5 The straight beam hinge arm exhibits good elasticity in the direction of movement (axial direction of push rod 401) and a certain degree of rigidity in the radial and rotational directions along push rod 401, enabling it to vibrate and twist, significantly improving product stability and extending product lifespan. A strain sensor 9 is attached to the side of the flexible hinge 4021. This invention uses the strain sensor 9 for real-time position detection and feedback, eliminating the hysteresis and creep characteristics of the piezoelectric ceramic 3. This invention employs closed-loop feedback control, greatly improving positioning accuracy and achieving nanometer-level precision control.

[0039] The first washer 5, the butterfly spring 6, and the locking nut 7 are all ring-shaped and are sequentially fitted onto the push rod 401 from bottom to top. The first washer 5, the butterfly spring 6, and the locking nut 7 are sequentially pressed against the top of the flexible hinge mechanism 402, as shown in the reference. Figure 3-4 The side wall of the locking nut 7 is threadedly connected to the inner side wall of the platform 2. The end of the push rod 401 away from the piezoelectric ceramic 3 passes through the nut 7 for connection to the load. The first washer 5 protects the hinge mechanism 402 and the disc spring 6. The disc spring 6 provides preload, and several can be provided depending on the stroke requirements. The end face of the locking nut 7 has a clamping hole 701 for easy installation.

[0040] In a preferred embodiment, the housing 1 is provided with a cooling connection port 102, which is used to connect to an external cooling device to prevent temperature from affecting the piezoelectric ceramic 3. The housing 1 is also provided with mounting holes 103 for mounting and fixing, facilitating connection and integration with other devices.

[0041] Example 2: The internal structure of this example is basically the same as that of Example 1, the main difference being that the outer shell 1 and the platform 2 are cylindrical. (Refer to...) Figure 6 .

[0042] Example 3: The internal structure of this example is basically the same as that of Example 1, with the main difference being that the outer shell 1 includes at least a first shell a and a second shell b with different cross-sections, and the first shell a and the second shell b are integrally formed. The shape and cross-sectional dimensions of the platform 2 are similar to the shape and cross-sectional dimensions of the first shell a to which it is connected, as shown in the reference. Figure 7 The structure of the outer shell 1 and the tabletop 2 is not limited to the embodiments listed in this invention, and various adjustments can be made according to the needs of the application scenario.

[0043] This invention is not intended to limit the scope of the invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A torsional piezoelectric actuator, characterized in that, include: The outer shell (1) has a first cavity (101) inside it; A tabletop (2) is provided on the outer shell (1), and the tabletop (2) and the outer shell (1) form a second cavity (201). A piezoelectric ceramic (3) is disposed in the first cavity (101) and extends through the first cavity (101) to the second cavity (201). The output structure (4) includes a push rod (401) and a flexible hinge mechanism (402) connected to the push rod (401). The flexible hinge mechanism (402) includes four flexible hinges (4021), which are arranged in a cross-shaped symmetrical structure. The flexible hinges (4021) are located in the second cavity (201) and connected to the outer shell (1). The bottom of the push rod (401) is coaxially connected to the piezoelectric ceramic (3), and the top of the push rod (401) penetrates the platform (2).

2. The anti-torsion piezoelectric actuator according to claim 1, characterized in that, The push rod (401) is fitted with a first washer (5), a butterfly spring (6) and a locking nut (7) from bottom to top. The first washer (5), the butterfly spring (6) and the locking nut (7) are pressed together in sequence. The side wall of the locking nut (7) is threadedly connected to the table surface (2).

3. The anti-torsion piezoelectric actuator according to claim 1, characterized in that, The piezoelectric ceramic (3) is connected to the push rod (401) via a second gasket (8).

4. The anti-torsion piezoelectric actuator according to claim 1, characterized in that, The end face of the locking nut (7) is provided with a clamping hole (701).

5. The anti-torsion piezoelectric actuator according to claim 1, characterized in that, The flexible hinge (4021) includes two parallel straight beam hinge arms.

6. The anti-torsion piezoelectric actuator according to claim 1, characterized in that, The flexible hinge (4021) is equipped with a strain sensor (9).

7. The anti-torsion piezoelectric actuator according to claim 1, characterized in that, The outer casing (1) is provided with a wind-cooling connection port (102).

8. The anti-torsion piezoelectric actuator according to claim 1, characterized in that, An adhesive layer (10) is provided between the end of the first cavity (101) and the piezoelectric ceramic (3) for sealing.

9. The anti-torsion piezoelectric actuator according to claim 1, characterized in that, The bottom of the outer shell (1) is provided with a base (11), the bottom of the piezoelectric ceramic (3) is connected to the base (11), and an adhesive layer (10) is provided between the outer shell (1) and the base (11) for sealing.

10. The anti-torsion piezoelectric actuator according to claim 1, characterized in that, The outer casing (1) is provided with mounting holes (103) for connecting to external mechanisms.

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