Compact displacement amplification device with multiple piezoelectric ceramic arrays

Abstract

A compact displacement amplifying device with multiple piezoelectric ceramic arrays comprises a shell, a base, three middle actuating assemblies with the same structure, a top-layer actuating assembly and three supporting beams with the same structure, the base, the three middle actuating assemblies, the top-layer actuating assembly and the three supporting beams are sequentially arranged in the shell from bottom to top, and a pre-tightening assembly is arranged between the top-layer actuating assembly and the base. According to the displacement amplifying device and method, the output displacement of the piezoelectric ceramic stack can be amplified, meanwhile, the output force of piezoelectric ceramics is reserved to a large extent, and the displacement amplifying device and method have the advantages of being compact in structure, high in rigidity and large in load.

Description

Technical Field

[0001] The present invention relates to a technology in the field of piezoelectric stepping motors, specifically a compact displacement amplification device with high stiffness and large load for a multi-piezoelectric ceramic array. Background Art

[0002] Piezoelectric ceramics are a new type of functional material that can convert mechanical energy and electrical energy into each other by using the piezoelectric effect and the inverse piezoelectric effect. A piezoelectric ceramic stack formed by bonding or co-firing multiple layers of piezoelectric ceramics is a new type of displacement actuator, which has a series of advantages such as small volume, fast response speed, large output force, and adaptability to vacuum environment. However, the output displacement of piezoelectric ceramics is limited. The stroke range of traditional piezoelectric ceramic stacks is from a few micrometers to nearly one hundred micrometers, which limits the scope of their engineering applications. In order to enable piezoelectric ceramics to have a larger motion driving stroke, a displacement amplification mechanism for piezoelectric ceramic stacks needs to be designed.

[0003] The amplification multiples of existing lever amplification structures and diamond amplification structures vary from several times to dozens of times. However, due to the existence of flexible structures, the stiffness and load capacity often decrease by several hundred times or even several thousand times. Piezoelectric stepping motors often drive by inertial force or friction force, and the load capacity is also severely limited. Therefore, existing amplification schemes cannot meet the application requirements of large load and high stiffness. In actual large-load piezoelectric ceramic applications, piezoelectric ceramic stacks need to be customized according to the required load and stroke, with high cost, long cycle, and large size. Summary of the Invention

[0004] The present invention aims at the problems of the prior art that it cannot directly output linear motion, can only achieve unidirectional motion, and the load capacity of the piezoelectric sheet friction drive scheme is relatively low, and proposes a compact displacement amplification device for a multi-piezoelectric ceramic array, which can amplify the output displacement of a piezoelectric ceramic stack and, at the same time, retain the displacement amplification device and its amplification method of the output force of the piezoelectric ceramic to a large extent, and has the advantages of compact structure, high stiffness, and large load.

[0005] The present invention is realized through the following technical solutions:

[0006] The present invention relates to a compact displacement amplification device for a multi-piezoelectric ceramic array, including: a housing, and a base, three identical intermediate actuation components, a top actuation component, and three identical support beams sequentially arranged inside the housing from bottom to top, wherein: a pre-tightening component is provided between the top actuation component and the base. Technical Effects

[0007] Through the series direct-push staggered stacking of multiple layers of intermediate actuating components and top actuating components, the present invention does not lose the output thrust of the piezoelectric ceramics and improves the compactness of the structure. The fan-shaped columns of the top actuating component and each layer of intermediate actuating components are meshed with each other, jointly restricting the displacement amplification device to only generate linear displacement along the axial direction, preventing the piezoelectric ceramic stack from being damaged when the structure is subjected to radial force and torsional force, and improving the reliability. The internal pre-tightening force enables the displacement amplification device to automatically return to zero, making up for the defect that the piezoelectric ceramic stack can only output thrust. Moreover, the pre-tightening force and its reaction force generate a restoring moment when the intermediate actuating component and the top actuating component are tilted, preventing the structure from jamming and ensuring that the piezoelectric ceramics are always subjected to a vertically downward pressure. Compared with the prior art, the displacement amplification multiple of the present device is equal to the number of stacked layers, facilitating flexible adjustment of the stacking scheme according to the actual requirements of the amplification ratio; the reduction ratio of stiffness is consistent with the displacement amplification ratio, with less stiffness loss; by arranging multiple small-sized piezoelectric ceramic stacks in an array, the need to customize large-sized piezoelectric ceramic stacks is avoided, and the economy is better. Brief Description of the Drawings

[0008] Figure 1 It is an explosion schematic diagram of the present device;

[0009] Figure 2 (a)-(f) are schematic diagrams of the overall structure of the present device and the cross-sections in each stacking direction;

[0010] Figure 3 (a)-(d) are schematic diagrams of the structure of the intermediate actuating component and the support beam of the present device combined;

[0011] Figure 4 (a)-(d) are schematic diagrams of the structure of the top actuating component and the top cover of the present device combined;

[0012] Figure 5 It is a schematic diagram of the finite element displacement-force feedback simulation of the present device;

[0013] In the figure: 1 top cover, 2 support beam, 3 pre-tightening component, 4 top actuating component, 5 intermediate actuating component, 6 base, 7 housing. Snap pin 8, thrust ball bearing 9, tension spring 10, through-hole set screw 11, screw 12, set screw 13, ceramic gasket 14, piezoelectric ceramic stack 15, top component bracket 17. Detailed Description of the Preferred Embodiment

[0014] As Figure 1As shown in the figure, this embodiment relates to a compact piezoelectric ceramic displacement amplification device, which includes: a housing and a base 6, three identical intermediate actuating components 5, a top actuating component 4, and three identical support beams 2 that are sequentially arranged inside from bottom to top, where: a preloading component 3 is provided between the top actuating component 4 and the base 6, and the top actuating component 4, the first intermediate actuating component 5, and the first to third intermediate actuating components 5 are stacked at an angle of 45°.

[0015] The housing includes a top cover 1 and an outer shell 7 connected thereto.

[0016] As Figure 2 Shown in (a)-(e), the mechanism is sectioned at an angle of 45° in the stacking order of the intermediate actuating component 5 and the top actuating component 4 from bottom to top to obtain sectional views A, B, C, and D. The first intermediate actuating component 5A at the bottom layer is stacked on the base 6, the second intermediate actuating component 5B is stacked on the bottom skirt of the first intermediate actuating component 5A, the third intermediate actuating component 5C is stacked on the bottom skirt of the second intermediate actuating component 5B, and the top actuating component 4 is stacked on the bottom skirt of the third intermediate actuating component 5C.

[0017] As Figure 2 Shown in (f), the preloading component 3 includes: a retaining pin 8, a thrust ball bearing 9, a tension spring 10, and a slotted set screw 11, where: the thrust ball bearing 9 is located inside the top actuating component 4, the slotted set screw 11 is clamped with the base 6, and the elongation of the tension spring 10 is adjusted by the relative position of the slotted set screw 11 and the base 6 to control the required preloading force of the mechanism.

[0018] As Figure 3 Shown in (a)-(c) are the front view, top view, and left view of the combined structure of the intermediate actuating component 5 and the support beam 2 in sequence. As Figure 3 Shown in (d), the intermediate actuating component 5 includes: an intermediate member bracket 16 and a pair of set screws 13, a pair of ceramic gaskets 14, and a pair of piezoelectric ceramic stacks 15 that are sequentially arranged thereon, where: the first to third support beams 2 are fixed to the tops of the intermediate member brackets 16 of the corresponding first to third intermediate actuating components 5 by a pair of screws 12, and the ceramic gaskets 14 are arranged at both ends of the piezoelectric ceramic stacks 15 to make the pressure on the contact surface evenly distributed; the distance that the piezoelectric ceramic stack 15 protrudes from the cavity of the intermediate member bracket 16 can be adjusted by adjusting the set screw 13.

[0019] The side surfaces of the cylindrical bosses of the first to third support beams 2 cooperate with the inner arc cylindrical surfaces of the intermediate member brackets 16 of the corresponding first to third intermediate actuating components 5 to limit the centripetal displacement of the tops of a pair of columns of the intermediate member bracket 16 and ensure the stiffness of the intermediate actuating component 5 when it is subjected to the thrust of the piezoelectric ceramic stack 15.

[0020] AsFigure 4 (a)-(d) As shown, the top actuating assembly 4 includes: a top component bracket 17, and a pair of set screws 13, a pair of ceramic gaskets 14, and a pair of piezoelectric ceramic stacks 15 sequentially arranged thereon, where: the top cover 1 is fixed to the center of the top component bracket 17 by a pair of screws 12; by adjusting the set screws 13, the pair of piezoelectric ceramic stacks 15 protrude slightly from the cavity of the top component bracket 17 by the same distance.

[0021] The lower cylindrical boss side of the top cover 1 is matched with the inner arc cylindrical surface of the top component bracket 17 to limit the centripetal displacement of the tops of the pair of columns of the top component bracket 17, and ensure the stiffness of the top actuating assembly 4 when subjected to the thrust of the piezoelectric ceramic stack 15.

[0022] The maximum stroke of the piezoelectric ceramic stack 15 is 50μm, the maximum thrust is 4000N, and the stiffness is 80N / μm. By magnifying the piezoelectric ceramic stack with a maximum stroke of 50μm to a maximum stroke of 200μm, the characteristics of large thrust and high stiffness of the piezoelectric ceramic stack are retained as much as possible.

[0023] As Figure 5 shown, in the finite element simulation scenario of 200μm displacement, the force feedback of this device is 5068.4N, and the converted stiffness is about 25.34N / μm, and the thrust and stiffness loss is about 36.6%.

[0024] In the prior art, to achieve the same thrust and stroke effects, a piezoelectric ceramic stack with dimensions of 14mm*14mm*200mm needs to be customized, and a corresponding additional mechanism needs to be designed to provide pre-tightening force and ensure that the force application direction is vertical. In this embodiment, this device realizes the equivalent effect of an extra-large-size customized piezoelectric ceramic stack through the combination of multiple smaller-size piezoelectric ceramic stacks, and realizes two additional functions of pre-tightening and motion constraint, reducing the development cost and development cycle. At the same time, the overall external dimension length is reduced by 50%, and the application range is wider.

[0025] Those skilled in the art can make local adjustments to the above specific implementation in different ways without departing from the principles and purposes of the present invention. The protection scope of the present invention is subject to the claims and is not limited by the above specific implementation, and all implementation solutions within its scope are subject to the constraints of the present invention.

Claims

1. A compact displacement amplification device for a multi-piezoelectric ceramic array, characterized in that include: The shell and the base, three intermediate actuating assemblies with the same structure, the top actuating assembly and three support beams with the same structure are arranged therein from bottom to top, wherein: a pre-tightening assembly is arranged between the top actuating assembly and the base, and the top actuating assembly and the first intermediate actuating assembly and the first to third intermediate actuating assemblies are stacked at an angle of 45°.

2. The compact displacement amplification device of the multi-piezoelectric ceramic array according to claim 1, characterized in that, The housing comprises a top cover and an outer shell connected thereto; The top actuating assembly comprises: a top component support and a pair of fixing screws, a pair of ceramic gaskets and a pair of piezoelectric ceramic stacks arranged thereon in sequence, wherein: the top cover is fixed to the center of the top component support by a pair of screws; by adjusting the fixing screws, the pair of piezoelectric ceramic stacks slightly protrude from the cavity of the top component support by the same distance.

3. The compact displacement amplification device of the multi-piezoelectric ceramic array according to claim 2, characterized in that, The side surface of the lower cylindrical boss of the top cover cooperates with the inner arc cylindrical surface of the top component bracket to limit the centripetal displacement of the top of a pair of columns of the top component bracket, thereby ensuring the stiffness of the top actuating assembly when subjected to the thrust of the piezoelectric ceramic stack.

4. The compact displacement amplification device of the multi-piezoelectric ceramic array according to claim 1, characterized in that, The preload assembly comprises: a bayonet, a thrust ball bearing, a tension spring and a perforated set screw, wherein: the thrust ball bearing is located in the top-level actuating assembly, the perforated set screw is engaged with the base, and the elongation of the tension spring is adjusted by the relative position of the perforated set screw and the base to control the preload force required by the mechanism.

5. The compact displacement amplification device of the multi-piezoelectric ceramic array according to claim 1, characterized in that, The intermediate actuating assembly comprises: an intermediate part bracket and a pair of fixing screws, a pair of ceramic gaskets and a pair of piezoelectric ceramic stacks arranged thereon in sequence, wherein: the first to third support beams are fixed to the top of the intermediate part bracket of the corresponding first to third intermediate actuating assemblies by a pair of screws, and the ceramic gaskets are arranged at both ends of the piezoelectric ceramic stack so that the pressure on the contact surface is evenly distributed; the distance of the piezoelectric ceramic stack protruding from the cavity of the intermediate part bracket can be adjusted by adjusting the fixing screws.

6. The compact displacement amplification device of the multi-piezoelectric ceramic array according to claim 5, characterized in that, The cylindrical boss side surfaces of the first to third support beams cooperate with the inner arc cylindrical surfaces of the intermediate part brackets of the corresponding first to third intermediate actuating assemblies to limit the centripetal displacement of the tops of a pair of columns of the intermediate part brackets, thereby ensuring the stiffness of the intermediate actuating assemblies when subjected to the thrust of the piezoelectric ceramic stack.

7. The compact displacement amplification device for a multi-piezoelectric ceramic array according to any one of claims 2-6, characterized in that, The piezoelectric ceramic stack has a maximum stroke of 50 μm, a maximum thrust of 4000 N, and a stiffness of 80 N / μm. The piezoelectric ceramic stack with a maximum stroke of 50 μm is enlarged to a maximum stroke of 200 μm, and the characteristics of the piezoelectric ceramic stack with large thrust and high stiffness are retained as much as possible.

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