Large-stroke compact piezoelectric actuator

Abstract

The invention relates to the technical field of precise instruments, and discloses a large-stroke compact piezoelectric actuator which comprises an inner shell, an outer shell, a flexible hinge mechanism, a first piezoelectric ceramic group and a second piezoelectric ceramic group. And the flexible hinge mechanism is connected with the inner shell and the outer shell. The first piezoelectric ceramic set is arranged in the first cavity, the fixed end of the first piezoelectric ceramic set is connected with the first base, and the movable end of the first piezoelectric ceramic set is connected with a movable rod. A mechanical pre-tightening structure is arranged between the moving rod and the first top cover in an abutting mode. The moving rod penetrates through the first through hole and the second through hole. The second piezoelectric ceramic set is arranged in the second cavity and connected with the second base and the first connecting ring. The inner shell is additionally arranged in the outer shell, and the first piezoelectric ceramic group and the second piezoelectric ceramic group which act synchronously are respectively arranged inside and outside the inner shell, so that large output and large stroke are realized, the structure is more compact, and integration is easier. And the flexible hinge mechanism and the strain sensor are arranged, so that the service life of the product is longer, the operation is more stable, and the precision is higher.

Description

Technical Field

[0001] The present invention belongs to the field of precision motion technology, and in particular, relates to a large-stroke compact piezoelectric actuator. Background Art

[0002] In the precision movement of micro-nano fields, piezoelectric ceramics have gained more and more attention because of their good frequency stability and high precision. However, when subjected to external forces such as tension, torsion and shear, the internal structure of piezoelectric ceramics is easily damaged. In order to protect the integrity and stable performance of the ceramics, a metal shell is usually added to its outer ring. This device is also called encapsulated ceramics. Actuators made of encapsulated piezoelectric ceramics have the characteristics of fast response speed and high precision, and are widely used in the industry. Piezoelectric actuators use the inverse piezoelectric effect to convert electrical energy into mechanical energy, and are widely used in industrial products in the fields of electronics and mechatronics.

[0003] The Chinese patent document of the prior art (authorization announcement number CN220822931U) discloses a fully sealed piezoelectric actuator, semiconductor device manufacturing equipment and optical communication equipment. The fully sealed piezoelectric actuator includes: a cylindrical shell and a hinge mechanism arranged at one end of the cylindrical shell and sealed to the shell. The hinge mechanism includes a hinge and a ball socket. The ball socket is connected to the hinge, and the end of the ball socket has a groove, which faces the inside of the shell and is used to accommodate the energy-dissipating ball. A piezoelectric ceramic is coaxially arranged inside the shell, and a gasket is arranged at one end of the piezoelectric ceramic, and the gasket is in point contact with the energy-dissipating ball. A base is arranged at one end of the shell away from the hinge mechanism, and the base is sealed to the shell and fixedly connected to one end of the piezoelectric ceramic away from the gasket. Two through holes are arranged on the base, and the axis of the through holes is parallel to the axis of the shell. Two pins pass through the two through holes respectively, and both ends of the pins protrude from the base. A sealing layer is arranged between the outer wall of the pin and the base. The fully sealed piezoelectric actuator provided by the prior art solves the problem that conventional piezoelectric actuators cannot be completely sealed, which can improve its reliability, extend its service life and provide higher performance. However, there are problems of low output and small stroke. For example, in order to increase the output and stroke of the prior art, the number of piezoelectric ceramics needs to be increased on the original piezoelectric ceramic stack length, which will inevitably increase the length of the entire device. On the one hand, the actuator with a long length is not convenient for integration. On the other hand, the piezoelectric ceramics in operation are prone to lateral movement and bending, which can easily damage the piezoelectric ceramics and result in poor product operation stability.

[0004] Based on the above, the current problem to be solved is to provide a compact piezoelectric actuator with a small size, high output, high precision and stability and a large stroke. Summary of the invention

[0005] The purpose of the present invention is to provide a compact piezoelectric actuator with a large stroke, aiming to solve the problems of small output, small stroke and unstable operation of the piezoelectric actuator in the prior art.

[0006] The present invention is implemented as follows: a large-stroke compact piezoelectric actuator, comprising:

[0007] The inner shell comprises a first top cover, a first base, a first side wall and a first cavity, wherein a first connecting ring is provided on the outer periphery of the first side wall; and a first through hole is provided on the first top cover;

[0008] An outer shell, comprising a second top cover, a second base, a second side wall and a second cavity; the second top cover is provided with a second through hole; the outer shell is arranged on the outer side of the inner shell;

[0009] A flexible hinge mechanism connecting the inner shell and the outer shell;

[0010] A first piezoelectric ceramic group is disposed in the first cavity; a fixed end of the first piezoelectric ceramic group is connected to the first base, and a moving end of the first piezoelectric ceramic group is connected to a moving rod; a mechanical pre-tightening structure is abutted between the moving rod and the first top cover, and an end of the moving rod away from the first piezoelectric ceramic group passes through the first through hole and the second through hole;

[0011] A second piezoelectric ceramic group is arranged in the second cavity, a fixed end of the second piezoelectric ceramic group is connected to the second base, a movable end of the second piezoelectric ceramic group is connected to the first connecting ring, and a mechanical pre-tightening structure is arranged between a side of the first connecting ring away from the second piezoelectric ceramic group and the second top cover.

[0012] Further, the flexible hinge mechanism includes a first flexible hinge group and a second flexible hinge group;

[0013] The first flexible hinge group includes a plurality of first flexible hinge arms, and two ends of the first flexible hinge arms are respectively connected to the first connecting ring and the second side wall;

[0014] The second flexible hinge group includes a plurality of second flexible hinge arms, and two ends of the second flexible hinge arms are respectively connected to the first base and the second base.

[0015] Furthermore, the first connecting ring includes protrusions for connecting the second piezoelectric ceramic group, a plurality of the protrusions are evenly distributed around the center of the first connecting ring, and the first flexible hinge arms are evenly distributed between the protrusions.

[0016] Furthermore, the second base includes a third through hole for accommodating the first base and a first groove for accommodating the second flexible hinge group; a cover is also provided at the bottom of the third through hole, and a cover groove for accommodating the cover is correspondingly provided on the second base.

[0017] Furthermore, a filling layer is provided in the first cavity and on the periphery of the first piezoelectric ceramic group.

[0018] Furthermore, strain sensors are provided on the surfaces of some piezoelectric ceramics of the first piezoelectric ceramic group.

[0019] Furthermore, the first piezoelectric ceramic group includes at least one first piezoelectric ceramic unit, and the first piezoelectric ceramic unit is formed by stacking a plurality of piezoelectric ceramics.

[0020] Furthermore, the second piezoelectric ceramic group includes a plurality of second piezoelectric ceramic units, and the second piezoelectric ceramic units are formed by stacking a plurality of piezoelectric ceramics; the plurality of second piezoelectric ceramic units are evenly arranged around the first connecting ring.

[0021] Furthermore, a ball or an internal thread or an external thread is provided at one end of the moving rod away from the first piezoelectric ceramic group.

[0022] Furthermore, a second connecting ring for connecting to the outside is provided on the outer periphery of the second side wall, and a mounting hole is provided on the second connecting ring.

[0023] The large-stroke compact piezoelectric actuator provided by the present invention has the following beneficial effects:

[0024] 1. Compared with the prior art, the present invention adds an inner shell inside the outer shell, and a first cavity and a second cavity are provided inside and outside the inner shell. The first cavity and the second cavity are respectively provided with a first piezoelectric ceramic group and a second piezoelectric ceramic group, and the first piezoelectric ceramic group and the second piezoelectric ceramic group act synchronously to achieve large output and large stroke. The present invention arranges a group of stacked narrow piezoelectric ceramics in the prior art into at least two groups of piezoelectric ceramics (the first piezoelectric ceramic group and the second piezoelectric ceramic group) laid flat, and the second piezoelectric ceramic group includes a plurality of uniformly arranged second piezoelectric ceramic units, so that the present invention has a more compact structure and is easier to integrate while achieving a large stroke, and the series structure has small motion coupling, which is suitable for integration into customized sports equipment.

[0025] Second, the present invention is provided with a flexible hinge mechanism. The first flexible hinge group and the second flexible hinge group can avoid the lateral force and bending force of the first piezoelectric ceramic group and the second piezoelectric ceramic group, extend the product life, and ensure the stability and precision of operation. The inner shell is provided with a filling layer to further avoid the lateral movement and bending of the first piezoelectric ceramic group, and effectively protect the first piezoelectric ceramic group.

[0026] 3. The present invention is provided with a mechanical pre-tightening structure to load the pre-tightening force, so that the present invention can withstand a certain tensile force, so that the first piezoelectric ceramic group and the second piezoelectric ceramic group are not easily damaged, and can be suitable for high-load and high-dynamic applications.

[0027] Fourth, a strain sensor is provided on the surface of the first piezoelectric ceramic group, so that the control voltage and the generated displacement are in a linear relationship, hysteresis and creep are eliminated, and the accuracy of the present invention is improved.

[0028] 5. The connection methods of the moving rod and other mechanical structures are set to flat head, ball head, internal thread, and external thread, which can be specially customized according to the requirements of the application scenario. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic diagram of the three-dimensional structure of the inner shell provided by the present invention;

[0030] Figure 2 It is a schematic diagram of the three-dimensional structure of a large-stroke compact piezoelectric actuator provided by the present invention;

[0031] Figure 3 A partial exploded view of a large-stroke compact piezoelectric actuator provided by the present invention;

[0032] Figure 4 A top view of the outer shell provided by the present invention;

[0033] Figure 5 A bottom view of the outer shell provided by the present invention;

[0034] Figure 6 A front view of a large-stroke compact piezoelectric actuator provided by the present invention;

[0035] Figure 7 The present invention provides Figure 6 Schematic diagram of the cross-section structure in the AA direction;

[0036] Figure 8 The present invention provides Figure 7 A partial enlarged view of

[0037] Fig. 9 The present invention provides Figure 6 Schematic diagram of the cross-section structure in the BB direction;

[0038] Fig.10 The present invention provides Figure 6 Schematic diagram of the cross-section structure in the CC direction;

[0039] In the figure: 1-inner shell; 11-first top cover; 111-first through hole; 12-first base; 13-first side wall; 14-first cavity; 15-first connecting ring; 151-protrusion; 2-outer shell; 21-second top cover; 211-second through hole; 22-second base; 221-third through hole; 222-first groove; 223-sealing groove; 23-second side wall; 24-second cavity; 25-sealing cover; 26-flange; 3-flexible hinge mechanism; 31-first flexible hinge group; 32-second flexible hinge group; 4-first piezoelectric ceramic group; 5-moving rod; 6-mechanical pre-tightening structure; 7-second piezoelectric ceramic group; 8-filling layer; 9-strain sensor; 10-sheath. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0041] The implementation of the present invention is described in detail below in conjunction with specific embodiments.

[0042] The same or similar numbers in the drawings of this embodiment correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the drawings, it is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limitations on this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0043] Reference Figure 1-10 The figure shows a preferred embodiment of the present invention.

[0044] A piezoelectric actuator comprises an inner housing 1, an outer housing 2, a flexible hinge mechanism 3, a first piezoelectric ceramic group 4 and a second piezoelectric ceramic group 7. The inner housing 1 comprises a first top cover 11, a first base 12, a first side wall 13, and a first cavity 14 enclosed by the first top cover 11, the first base 12 and the first side wall 13. Figure 1. A first connecting ring 15 for connecting to the second piezoelectric ceramic group 7 is provided on the outer periphery of the upper portion of the first side wall 13. A first through hole 111 is provided in the middle portion of the first top cover 11. In order to facilitate assembly, the first top cover 11, the first base 12 and the first side wall 13 are formed separately, and the three are assembled to form the inner shell 1. In a preferred connection method, external threads are provided on the outer sides of the four sides of the first top cover 11 and the first base 12, and internal threads matching the first top cover 11 and the first base 12 are provided on the inner sides of the two ends of the hollow first side wall 13, respectively. The external threads and the internal threads cooperate with each other to fix the first top cover 11 and the first side wall 13, and the first side wall 13 and the first base 12 are respectively fixedly connected.

[0045] The outer shell 2 is sleeved on the outer side of the inner shell 1. The outer shell 2 includes a second top cover 21, a second base 22, a second side wall 23, and a second cavity 24 surrounded by the second top cover 21, the second base 22, and the second side wall 23. A second through hole 211 is provided in the middle of the second top cover 21, and the inner shell 1 is disposed in the second cavity 24. Figure 2-5 . Preferably, the central axes of the first through hole 111 and the second through hole 211 are parallel. The second through hole 211 is larger than the first top cover 11, and the second top cover 21 is sleeved on the outside of the first top cover 11. In order to facilitate assembly, the second top cover 21, the second base 22 and the second side wall 23 are formed separately, and the three are assembled to form the outer shell 2. The preferred connection method is that the outer side of the second top cover 21 is provided with an external thread on all sides, and the inner side of the upper part of the hollow second side wall 23 is provided with an internal thread matching the external thread of the second top cover 21, and the external thread and the internal thread cooperate with each other to fix the second top cover 21 and the second side wall 23. A threaded hole is provided at the bottom of the second side wall 23, and threaded holes are provided at positions corresponding to the second base 22 and the second side wall 23. The second base 22 and the second side wall 23 are fixedly connected by bolts and threaded holes that cooperate with each other.

[0046] The first piezoelectric ceramic group 4 is disposed in the first cavity 14. Figure 6-8. The first piezoelectric ceramic group 4 includes a fixed end and a movable end. The fixed end of the first piezoelectric ceramic group 4 is fixedly connected to the first base 12, and the movable end of the first piezoelectric ceramic group 4 is connected to a movable rod 5. One end of the movable rod 5 is fixedly connected to the movable end of the first piezoelectric ceramic group 4, and the other end of the movable rod 5 passes through the first through hole 111 and the second through hole 211, and extends to the top of the first top cover 11. A mechanical pre-tightening structure 6 is arranged between the end of the movable rod 5 connected to the first piezoelectric ceramic group 4 and the first top cover 11, preferably a disc spring, and the disc spring is sleeved on the outer side of the movable rod 5 and abuts between the end of the movable rod 5 close to the first piezoelectric ceramic group 4 and the first top cover 11. The number of disc springs is set as needed, preferably 2. The movable rod 5 can move back and forth along the central axis direction of the first through hole 111 under the push of the first piezoelectric ceramic group 4. In order to adapt to other devices and meet specific settings, the top surface of the moving rod 5 can be set to a plane or provided with balls; the outer periphery of the moving rod 5 is provided with an external thread or the inner periphery of the moving rod 5 is provided with an internal thread.

[0047] The first piezoelectric ceramic group 4 includes at least one first piezoelectric ceramic unit. The first piezoelectric ceramic unit is formed by stacking a number of piezoelectric ceramics. Preferably, the central axis of the first piezoelectric ceramic unit is parallel to the central axis of the first through hole 111. In order to limit the lateral movement and bending of the first piezoelectric ceramic group 4, a filling layer 8 is preferably provided in the first cavity 14 and on the periphery of the first piezoelectric ceramic group 4. A strain sensor 9 is provided on the surface of some piezoelectric ceramics of the first piezoelectric ceramic group 4. The strain sensor 9 is preferably arranged on the surface of the piezoelectric ceramic connected to the moving rod 5 of the first piezoelectric ceramic group 4. The setting of the strain sensor 9 can control the linear relationship between the voltage and the generated displacement, eliminate hysteresis and creep, and improve the accuracy of the present invention.

[0048] The second piezoelectric ceramic group 7 is arranged on the outside of the inner shell 1 and in the second cavity 24. The second piezoelectric ceramic group 7 includes a fixed end and a movable end. The fixed end of the second piezoelectric ceramic group 7 is fixedly connected to the second base 22. The movable end of the second piezoelectric ceramic group 7 is fixedly connected to the first connecting ring 15. A mechanical pre-tightening structure 6 is provided between the side of the first connecting ring 15 away from the second piezoelectric ceramic group 7 and the second top cover 21, and the mechanical pre-tightening structure 6 is preferably a disc spring. The number of disc springs is set as needed, preferably 2. The second piezoelectric ceramic group 7 pushes the first connecting ring 15, and the first connecting ring 15 drives the inner shell 1 to move back and forth along the central axis direction of the first through hole 111. The first piezoelectric ceramic group 4 and the second piezoelectric ceramic group 7 act synchronously, so that the inner shell 1 and the moving rod 5 act synchronously, and the series structure of the present invention has small motion coupling. The second piezoelectric ceramic group 7 includes a plurality of second piezoelectric ceramic units. The second piezoelectric ceramic unit is formed by stacking a plurality of piezoelectric ceramics. The number of the second piezoelectric ceramic units is greater than or equal to 1, for example, 3 or 4 are set, and the second piezoelectric ceramic units are evenly distributed around the first piezoelectric ceramic group 4. Preferably, the central axis of the second piezoelectric ceramic unit is parallel to the central axis of the first piezoelectric ceramic unit. Further, a filling layer 8 can be provided in the second cavity 24 and on the outer periphery of the second piezoelectric ceramic group 7 to avoid lateral force and bending force of the second piezoelectric ceramic group 7.

[0049] Compared with the prior art, the present invention adds an inner shell 1 inside the outer shell 2, and a first cavity 14 and a second cavity 24 are provided inside and outside the inner shell 1. The first cavity 14 and the second cavity 24 are respectively arranged with a first piezoelectric ceramic group 4 and a second piezoelectric ceramic group 7, and the first piezoelectric ceramic group 4 and the second piezoelectric ceramic group 7 act synchronously, so that the present invention has a large output and a large stroke. The present invention arranges a group of stacked narrow piezoelectric ceramics in the prior art into at least two groups of piezoelectric ceramics (the first piezoelectric ceramic group 4 and the second piezoelectric ceramic group 7) that are laid flat, and the second piezoelectric ceramic group 7 can include a plurality of uniformly arranged second piezoelectric ceramic units, so that the present invention has a more compact structure and is easier to integrate while achieving a large stroke.

[0050] In order to limit the lateral movement and bending of the first piezoelectric ceramic group 4 and the second piezoelectric ceramic group 7, a flexible hinge mechanism 3 is provided between the inner shell 1 and the outer shell 2. Preferably, at least two groups of flexible hinge groups are provided, including a first flexible hinge group 31 and a second flexible hinge group 32, respectively. The first flexible hinge group 31 is provided between the first connecting ring 15 and the second side wall 23. The first flexible hinge group 31 includes a plurality of first flexible hinge arms. Preferably, the plurality of first flexible hinge arms are evenly distributed between the first connecting ring 15 and the second side wall 23. By providing the first flexible hinge group 31 and the second flexible hinge group 32, the lateral force and bending force of the first piezoelectric ceramic group 4 and the second piezoelectric ceramic group 7 can be avoided, the product life can be extended, and the stability and precision of operation can be ensured.

[0051] In a further preferred embodiment, the first connecting ring 15 includes a protrusion 151, referring to Figure 1 , Fig. 9 , Fig.10 A plurality of protrusions 151 are evenly distributed around the first connecting ring 15 around the center of the first connecting ring 15. A first piezoelectric ceramic group 4 is fixed to the bottom of the protrusion 151. The first flexible hinge arms are evenly distributed between the protrusions 151, and the number of the protrusions 151 corresponds to the number of the second piezoelectric ceramic units. For example, three second piezoelectric ceramic units and three protrusions 151 corresponding to the second piezoelectric ceramic units are provided, and six first flexible hinge arms are evenly distributed between the three protrusions 151.

[0052] The second flexible hinge group 32 includes a plurality of second flexible hinge arms, which are evenly distributed between the first base 12 and the second base 22. Preferably, the first base 12, the second base 22 and the two ends of the second flexible hinge arm are respectively provided with threaded holes, and the two ends of the second flexible hinge arm are respectively fixedly connected to the first base 12 and the second base 22 by bolts and threaded holes. The number of the second flexible hinge arms is set as required, for example, 3 can be set. The second base 22 includes a third through hole 221 provided in the middle for accommodating the first base 12, and a first groove 222 for accommodating the second flexible hinge group 32. A cover 25 for sealing the outer shell 2 is also provided at the bottom of the third through hole 221. A cover groove 223 for accommodating the cover 25 is correspondingly provided on the second base 22. A flange 26 for connecting with an external device is provided on the outer periphery of the second side wall 23, and a threaded hole can also be provided on the second base 22 to connect with the external device by bolts. A hollow sheath 10 for passing an external wire is also provided at the bottom of the second base 22.

[0053] The present invention is not limited thereto; any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A large-stroke compact piezoelectric actuator, characterized in that: include: An inner shell (1) comprises a first top cover (11), a first base (12), a first side wall (13) and a first cavity (14); a first connecting ring (15) is provided on the outer periphery of the first side wall (13); and the first top cover (11) is provided with a first through hole (111); An outer shell (2), comprising a second top cover (21), a second base (22), a second side wall (23) and a second cavity (24); the second top cover (21) is provided with a second through hole (211); the outer shell (2) is arranged on the outside of the inner shell (1); A flexible hinge mechanism (3) connecting the inner shell (1) and the outer shell (2); A first piezoelectric ceramic group (4) is arranged in the first cavity (14); a fixed end of the first piezoelectric ceramic group (4) is connected to the first base (12), and a movable end of the first piezoelectric ceramic group (4) is connected to a movable rod (5); a mechanical pre-tightening structure (6) is abutted between the movable rod (5) and the first top cover (11), and an end of the movable rod (5) away from the first piezoelectric ceramic group (4) passes through the first through hole (111) and the second through hole (211); A second piezoelectric ceramic group (7) is disposed in the second cavity (24); a fixed end of the second piezoelectric ceramic group (7) is connected to the second base (22); a movable end of the second piezoelectric ceramic group (7) is connected to the first connecting ring (15); and a mechanical pre-tightening structure (6) is disposed between a side of the first connecting ring (15) away from the second piezoelectric ceramic group (7) and the second top cover (21).

2. The large-stroke compact piezoelectric actuator according to claim 1, characterized in that: The flexible hinge mechanism (3) comprises a first flexible hinge group (31) and a second flexible hinge group (32); The first flexible hinge group (31) comprises a plurality of first flexible hinge arms, and two ends of the first flexible hinge arms are respectively connected to the first connecting ring (15) and the second side wall (23); The second flexible hinge group (32) comprises a plurality of second flexible hinge arms, and two ends of the second flexible hinge arms are respectively connected to the first base (12) and the second base (22).

3. The large-stroke compact piezoelectric actuator according to claim 2, characterized in that: The first connecting ring (15) comprises a protrusion (151) for connecting the second piezoelectric ceramic group (7), a plurality of the protrusions (151) are evenly distributed around the center of the first connecting ring (15), and the first flexible hinge arms are evenly distributed between the plurality of the protrusions (151).

4. The large-stroke compact piezoelectric actuator according to claim 2, characterized in that: The second base (22) comprises a third through hole (221) for accommodating the first base (12) and a first groove (222) for accommodating a second flexible hinge group (32); a cover (25) is also provided at the bottom of the third through hole (221), and a cover groove (223) for accommodating the cover (25) is correspondingly provided on the second base (22).

5. The large-stroke compact piezoelectric actuator according to claim 1, characterized in that: A filling layer (8) is provided in the first cavity (14) and on the outer periphery of the first piezoelectric ceramic group (4).

6. The large-stroke compact piezoelectric actuator according to claim 1, characterized in that: Strain sensors (9) are provided on the surfaces of some piezoelectric ceramics of the first piezoelectric ceramic group (4).

7. The large-stroke compact piezoelectric actuator according to claim 1, characterized in that: The first piezoelectric ceramic group (4) comprises at least one first piezoelectric ceramic unit, wherein the first piezoelectric ceramic unit is formed by stacking a plurality of piezoelectric ceramics.

8. The large-stroke compact piezoelectric actuator according to claim 1, characterized in that: The second piezoelectric ceramic group (7) comprises a plurality of second piezoelectric ceramic units, wherein the second piezoelectric ceramic units are formed by stacking a plurality of piezoelectric ceramics; the plurality of second piezoelectric ceramic units are evenly arranged around the first connecting ring (15).

9. The large-stroke compact piezoelectric actuator according to claim 1, characterized in that: One end of the moving rod (5) away from the first piezoelectric ceramic group (4) is provided with a ball or an internal thread or an external thread.

10. The large-stroke compact piezoelectric actuator according to claim 1, characterized in that: The outer periphery of the second side wall (23) is provided with a flange (26) for connecting to external equipment.

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