A bearingless arc piezoelectric motor

Abstract

The present invention discloses a bearingless arc-shaped piezoelectric motor comprising an inchworm piezoelectric drive module and a C-shaped arc-shaped mover. The inner arc surface and the inner side surface of the arc-shaped mover are chamfered at a 45° angle at their intersection to form an inner chamfered surface, which serves as a contact surface for the inchworm piezoelectric drive module on the inner chamfered surface. The inner chamfered surface inchworm piezoelectric drive module is arranged along an arc line at ±25° on the concentric arc of the mover's inner chamfered surface, while the outer side surface and outer arc surface inchworm piezoelectric drive modules are arranged at 0° and 0° on the outer side surface and outer arc surface, respectively. Under the action of a preload, the inchworm piezoelectric drive module provides a normal clamping force along the arc surface for the contact surface on the mover. The normal clamping force of each inchworm piezoelectric drive module is balanced in the thrust component of the non-motional degree of freedom, providing non-motional degree of freedom constraints for the mover. When powered on, the mover is subjected to tangential driving force from the inner chamfered surface, outer side surface, and outer arc surface inchworm piezoelectric drive module in the direction of arc motion, thereby realizing bearingless arc guided motion of the mover.

Description

Technical Field

[0001] The present invention relates to the technical field of precision actuators, and in particular to a bearingless arc-shaped piezoelectric motor. Background Art

[0002] In a focused ion beam-electron beam dual-beam microscope, the scanning electron beam (SEM) primarily observes and locates sample features of interest (such as defects and interfaces), while the focused ion beam (FIB) performs micro-nano processing on these features. Within a vacuum chamber, the SEM and FIB are concentrically arranged at a specific angle. During processing, the sample is placed on a five-axis vacuum worktable. The five-axis worktable must adjust its position and orientation according to commands from the host computer, regulating its concentric motion to enable inspection and processing of the sample on the worktable. Therefore, the five-axis worktable must simultaneously possess X- and Y-axis motion, Z-axis focusing, rotational axis motion, and pitch-axis motion. The pitch axis is primarily used to switch between SEM and FIB modes; therefore, the worktable's pitch axis travel must be greater than the concentric angle between the SEM and FIB. Traditionally, the pitch axis design utilizes a combination of a linear drive motor and an arc-shaped guide. However, the dual-beam microscope's vacuum, non-magnetic, athermal, and long pitch and tilt motion requirements limit the choice of arc-shaped guides, which in turn affects the design of the pitch and tilt axes. Therefore, designing a long-travel, integrated, compact, non-magnetic, athermal, and high-precision arc-shaped motion axis is crucial for a five-axis vacuum worktable. Summary of the Invention

[0003] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a bearingless, high-rigidity arc-shaped piezoelectric motor. The motor adopts a multi-legged inchworm actuator, and through the optimized layout of the multi-legged inchworm actuator, the full-stroke arc guidance and drive of the arc motor are achieved at the same time.

[0004] In the present invention, the bearingless arc-shaped piezoelectric motor is a inchworm piezoelectric ceramic motor, which includes an inchworm piezoelectric drive module and a C-shaped arc-shaped mover. One corner of the inner arc surface of the C-shaped arc-shaped mover is chamfered at 45 degrees as the contact surface of the inner chamfered surface inchworm piezoelectric drive module, and the outer side surface and outer arc surface of the C-shaped arc-shaped mover serve as the contact surfaces of the outer side inchworm piezoelectric drive module and the outer arc surface inchworm piezoelectric drive module, respectively. Under the action of preload, the two inner chamfered surface inchworm piezoelectric drive modules provide radial force along the C-shaped arc mover to the inner 45° chamfered surface of the C-shaped arc-shaped mover, and the outer side inchworm piezoelectric drive module and the outer arc surface inchworm piezoelectric drive module provide normal force along the outer side surface and outer arc surface of the C-shaped arc-shaped mover. The preload force of each inchworm piezoelectric drive module achieves thrust balance and provides non-motion freedom constraint for the C-shaped arc-shaped mover. When powered, the C-shaped arc-shaped mover receives tangential driving forces along its arcuate direction from the inner chamfered surface piezoelectric drive module, the outer surface piezoelectric drive module, and the outer arc surface piezoelectric drive module. This enables bearingless, arc-guided motion of the C-shaped arc-shaped mover along its arcuate direction. The technical solution of this invention is described in detail below.

[0005] A bearingless arc-shaped piezoelectric motor comprises a base, an inchworm piezoelectric drive module and a C-shaped arc-shaped mover; the inchworm piezoelectric drive module is mounted on the base, the inchworm piezoelectric drive module comprises two inner chamfered surface inchworm piezoelectric drive modules, an outer surface inchworm piezoelectric drive module and an outer arc surface inchworm piezoelectric drive module, the C-shaped arc-shaped mover is arranged between the inner chamfered surface inchworm piezoelectric drive module, the outer surface inchworm piezoelectric drive module and the outer arc surface inchworm piezoelectric drive module, and the inner arc surface of the C-shaped mover is A 45° chamfer is performed at the junction with the inner side surface to form an inner chamfer surface, which serves as a contact surface and contacts the inchworm piezoelectric drive module on the inner chamfer surface. The inchworm piezoelectric drive module on the inner chamfer surface is arranged along the arc line at a position of ±25° on the concentric arc of the inner chamfer surface of the C-shaped arc mover. The inchworm piezoelectric drive module on the outer side is arranged at a position of 0° on the outer side of the C-shaped arc mover. The inchworm piezoelectric drive module on the outer arc surface is arranged at a position of 0° on the outer arc surface of the C-shaped arc mover, and the inchworm piezoelectric drive module on the outer arc surface is arranged at a position of 0° on the outer arc surface of the C-shaped arc mover, so as to jointly complete the constraint and guidance of the C-shaped arc mover; wherein:

[0006] The inner chamfered surface inchworm piezoelectric drive module, the outer surface inchworm piezoelectric drive module and the outer arc surface inchworm piezoelectric drive module are respectively composed of a flexible hinge shell and two piezoelectric stack legs; the shell with a flexible hinge includes a flexible hinge that provides fixed stiffness to the piezoelectric stack and a shell for fixing the piezoelectric module; the piezoelectric stack legs are respectively composed of a tangential ceramic stack, a normal ceramic stack and a ceramic antenna to realize the normal extension and contraction and tangential reciprocating motion of the piezoelectric stack legs. The two piezoelectric stack legs move in an interlaced manner to provide normal constraint force and tangential motion force to the C-shaped arc mover, thereby realizing the bearingless arc-guided motion of the C-shaped arc mover along the arc motion direction.

[0007] In the present invention, the contact surface between the inner chamfered surface inchworm piezoelectric drive module and the C-shaped arc-shaped mover is a circular arc surface, and the contact antennae between the piezoelectric stack legs in the inner chamfered surface inchworm piezoelectric drive module and the C-shaped arc-shaped mover are arched ceramic antennae; the contact antennae between the outer surface inchworm piezoelectric drive module and the outer arc-shaped inchworm piezoelectric drive module are flat ceramic antennae.

[0008] In the present invention, the inner chamfered surface inchworm piezoelectric drive module is installed on the base through a fixed bracket.

[0009] In the present invention, the outer side inchworm piezoelectric drive module and the outer arc surface inchworm piezoelectric drive module are installed on the base.

[0010] A preload adjustment screw is provided at the seat installation position, and the preload installation of the entire bearingless arc-shaped piezoelectric motor is achieved by adjusting the tightness of the preload adjustment screw.

[0011] In the present invention, the inner side of the circular mover is chamfered at 45° to form a chamfered surface, which serves as a contact surface and contacts the inchworm piezoelectric drive module on the inner chamfered surface.

[0012] In the present invention, the C-shaped arc-shaped mover is replaced by a linear mover, and the inner side of the linear mover is chamfered at 45° to form a chamfered surface, which serves as a contact surface and contacts the inner chamfered surface of the inchworm piezoelectric drive module.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] The present invention does not require an additional guide mechanism to achieve arc motion, and has the advantages of integrated drive and guide, thereby achieving higher guide rigidity, a more compact structure, and unconstrained arc motion stroke. The present invention is easy to assemble and does not require additional pre-tightening assembly tooling. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the overall structure of the bearingless arc-shaped piezoelectric motor provided by the present invention.

[0016] Figure 2 It is a schematic diagram of the overall structure of specific embodiment 1 provided by the present invention.

[0017] Figure 3 Schematic diagram of the inchworm piezoelectric drive module of specific embodiment 1 provided by the present invention.

[0018] Figure 4 It is a schematic diagram of the base of specific embodiment 1 provided by the present invention.

[0019] Figure 5 It is a schematic diagram of a C-shaped arc mover according to specific embodiment 1 provided by the present invention.

[0020] Figure 6It is a schematic diagram of the angular orientation of the C-shaped arc mover of the specific embodiment 1 provided by the present invention.

[0021] Figure 7 It is a schematic diagram of the force analysis of the motor according to the specific embodiment 1 provided by the present invention.

[0022] Figure 8 It is a structural diagram of specific embodiment 2 provided by the present invention.

[0023] Figure 9 It is a structural diagram of specific embodiment 3 provided by the present invention.

[0024] Numbers in the figure: 1-base, 21-first fixed bracket, 22-second fixed bracket, 21 and 22 form 2-fixed bracket, 31-first inner chamfered surface inchworm piezoelectric drive module, 32-second inner chamfered surface inchworm piezoelectric drive module, 31 and 32 form 3-inner chamfered surface inchworm piezoelectric drive module, 4-outer arc surface inchworm piezoelectric drive module, 5-C-shaped arc mover, 6-outer side inchworm piezoelectric drive module, 311, 41-flexible hinge housing, 312, 313-inner chamfered surface piezoelectric stack legs , 42, 43-outer arc surface piezoelectric stack legs, 3111, 411-shell, 3112, 412-flexible hinge, 3121, 3131-arched ceramic tentacles, 421, 431-flat ceramic tentacles, 3122, 3132, 422, 432-tangential ceramic stacks, 3123, 3133, 423, 433-normal ceramic stacks, 11, 12, 13, 14-preloaded screw holes, 7-circular inner side 45° chamfered mover, 8-straight inner side 45° chamfered mover. DETAILED DESCRIPTION

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0026] In the description of the embodiments of the present invention, unless otherwise expressly specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and may refer to internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0027] In the embodiments of the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature includes the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0028] In the description of the embodiments of the present invention, terms such as "upper," "lower," "right," "inner," and "outer" are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely for ease of description and simplified operation. They do not indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and have no special meanings.

[0029] A specific embodiment 1 proposed by the present invention is as follows Figure 1-Figure 7 As shown, the proposed bearingless arc piezoelectric motor includes a base 1, a fixed bracket 2, an inner chamfered surface inchworm piezoelectric drive module 3, an outer arc surface inchworm piezoelectric drive module 4, a C-shaped arc mover 5, and an outer surface inchworm piezoelectric drive module 6.

[0030] The motor's stator is comprised of a base 1, a fixed bracket 2, an inner chamfered surface inchworm piezoelectric drive module 3, an outer arc surface inchworm piezoelectric drive module 4, and an outer side inchworm piezoelectric drive module 6. The inner chamfered surface inchworm piezoelectric drive module 3 includes a first inner chamfered surface inchworm piezoelectric drive module 31 and a second inner chamfered surface inchworm piezoelectric drive module 32. The fixed bracket 2 includes a first fixed bracket 21 and a second fixed bracket 22. The inner chamfered surface inchworm piezoelectric drive module 3 is fixed to the fixed bracket 2, which is fixed to the base 1. The outer arc surface inchworm piezoelectric drive module 4 and the outer side inchworm piezoelectric drive module 6 are directly fixed to the base 1.

[0031] The C-shaped arc-shaped mover 5 includes an inner arc surface 51 , a 45° inner chamfered surface 52 , an outer side surface 53 , and an outer arc surface 54 .

[0032] The first inner chamfered surface inchworm piezoelectric drive module 31 and the second inner chamfered surface inchworm piezoelectric drive module 32 have identical structures and are mounted on the first fixed bracket 21 and the second fixed bracket 22, respectively. The first inner chamfered surface inchworm piezoelectric drive module 31 and the second inner chamfered surface inchworm piezoelectric drive module 32 are mounted on the first fixed bracket 21 and the second fixed bracket 22, respectively, at ±25° arc positions concentric with the inner chamfered surface 52. The outer arc surface inchworm piezoelectric drive module 4 is mounted at the 0° position on the outer arc surface 54 of the C-shaped arc mover 5, and the outer side surface inchworm piezoelectric drive module 4 is mounted at the 0° position on the outer side surface 53 of the C-shaped arc mover 5.

[0033] The first inner chamfered surface inchworm piezoelectric drive module 31 includes a flexible hinge housing 311 and inner chamfered surface piezoelectric stack legs 312 and 313. These stack legs 312 and 313 are mounted on the flexible hinge 3112 of the flexible hinge housing 311. The inner chamfered surface piezoelectric stack legs 312 and 313 have identical structures, including an arched ceramic feeler 3121, a tangential ceramic stack 3122 with telescopic motion, and a normal ceramic stack 3123 with tangential reciprocating motion.

[0034] The outer-arc surface inchworm piezoelectric drive module 4 also includes a flexible hinge housing 41 and outer-arc surface piezoelectric stack legs 42 and 43. These stack legs 42 and 43 are mounted on the flexible hinge 412 of the flexible hinge housing 41. The outer-arc surface piezoelectric stack legs 42 and 43 have the same structure, including a planar ceramic antenna 421, a tangential ceramic stack 422, and a normal ceramic stack 423. The outer-arc surface inchworm piezoelectric drive module 6 has the same structure as the outer-arc surface inchworm piezoelectric drive module.

[0035] The inner chamfered surface inchworm piezoelectric drive module 3 contacts the 45° chamfered inner chamfered surface of the C-shaped arc-shaped mover 5 via multiple arched ceramic feelers 3121 on the four inner chamfered surface piezoelectric stack legs 312. The outer arc-shaped surface inchworm piezoelectric drive module 4 contacts the 45° chamfered outer surface of the C-shaped arc-shaped mover 5 via multiple arched ceramic feelers 421 on the two outer arc-shaped surface piezoelectric stack legs 42. The preload force of the outer arc-shaped surface inchworm piezoelectric drive module 4 is adjusted by screws in preload screw holes 13 and 14 on the base 1. The preload force of the outer arc-shaped surface inchworm piezoelectric drive module 6 is adjusted by screws in preload screw holes 11 and 12 on the base 1.

[0036] Taking the above-mentioned embodiment of the present invention in which the outer arc surface inchworm piezoelectric drive module 4 is a piezoelectric drive module, the outer surface inchworm piezoelectric drive module 6 is a piezoelectric drive module, and the inner chamfered surface inchworm piezoelectric drive module 3 is composed of two piezoelectric drive modules as an example, the working principle of the bearingless arc piezoelectric motor of the present invention is as follows:

[0037] The first inner chamfered surface inchworm piezoelectric driving module 31 provides a normal clamping force F2 along the chamfered surface for the 45° inner chamfered surface 52 of the C-shaped arc-shaped mover 5 under the preload clamping force. The normal clamping force F2 can be decomposed into a tangential component force F along the 45° inner chamfered surface 52 of the C-shaped arc-shaped mover 5. 2，1 and radial force F 2，2 The second inner chamfered surface inchworm piezoelectric drive module 32 provides a normal clamping force F4 along the normal direction of the chamfered surface for the 45° inner chamfered surface 52 of the C-shaped arc mover 5 under the preload clamping force. The clamping force F4 can be decomposed into a tangential component force F 4，1 and radial force F 4，2 Under the preload clamping, the outer arc surface inchworm piezoelectric drive module 4 provides a normal clamping force F3 along the normal direction of the outer arc surface 54 for the outer arc surface 54 of the C-shaped arc-shaped mover 5. Under the preload clamping, the outer side inchworm piezoelectric drive module 6 provides a normal clamping force F1 along the normal direction of the outer side surface 5 for the outer side surface 53 of the C-shaped arc-shaped mover 5. The magnitude relationship of the normal clamping forces F1, F2, F3, and F4 satisfies

[0038] F 2，1 +F 4，1 =F1

[0039] F 2，2 +F 4，2 =F3

[0040] This achieves the constraint of the non-motional degrees of freedom of the C-shaped arc mover 5. In the energized driving state, the first inner chamfered surface inchworm piezoelectric drive module 31 and the second inner chamfered surface inchworm piezoelectric drive module 32 provide the C-shaped arc mover 5 with tangential forces F'2 and F'4 along the 45° inner chamfered surface 52. The outer arc surface inchworm piezoelectric drive module 4 provides the C-shaped arc mover 5 with a tangential force F'3 tangential to the outer arc surface 54. The outer surface inchworm piezoelectric drive module 6 provides the C-shaped arc mover 5 with a tangential force F'1 tangential to the outer surface 53. The tangential forces F'1, F'2, F'3, and F'4 together constitute the tangential driving force of the C-shaped arc mover 5 along the direction of arc motion, thereby achieving bearingless arc-guided motion of the C-shaped arc mover 5 along the direction of arc motion.

[0041] A specific embodiment 2 provided by the present invention is as follows Figure 8 As shown, the C-shaped arc-shaped mover 5 is replaced with a circular mover, and the inner side of the circle is chamfered at 45° to form a circular inner side 45° chamfered mover 7. Two inner chamfered surface inchworm piezoelectric drive modules 3, one outer arc surface inchworm piezoelectric drive module 4, and one outer surface inchworm piezoelectric drive module 6 are further arranged to form a bearingless rotary piezoelectric motor.

[0042] A specific embodiment 3 provided by the present invention is as follows Figure 9As shown, the C-shaped arc-shaped mover 5 is replaced with a linear mover, and the inner side of the linear mover is chamfered 45° to form a linear inner side 45° chamfered mover 8, and two inner chamfered surface inchworm piezoelectric drive modules 3, one outer arc surface inchworm piezoelectric drive module 4, and one outer surface inchworm piezoelectric drive module 6 are further arranged to form a bearingless linear piezoelectric motor.

[0043] Note that the above are only preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will appreciate that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, combinations, and substitutions are possible for those skilled in the art without departing from the scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the scope of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A bearingless arc piezoelectric motor, characterized in that: It includes a base, an inchworm piezoelectric drive module and a C-shaped arc mover; The inchworm piezoelectric drive module is installed on the base. The inchworm piezoelectric drive module includes two inner chamfered surface inchworm piezoelectric drive modules, an outer surface inchworm piezoelectric drive module and an outer arc surface inchworm piezoelectric drive module. The C-shaped arc mover is set between the inner chamfered surface inchworm piezoelectric drive module, the outer surface inchworm piezoelectric drive module and the outer arc surface inchworm piezoelectric drive module. The inner arc surface and the inner surface of the C-shaped arc mover are chamfered at 45 degrees to form an inner arc. The chamfered surface serves as a contact surface for contacting the inchworm piezoelectric drive module on the inner chamfered surface. The inchworm piezoelectric drive module on the inner chamfered surface is arranged along the arc line at a position of ±25° on the concentric arc of the inner chamfered surface of the C-shaped arc mover. The inchworm piezoelectric drive module on the outer surface is arranged at a position of 0° on the outer surface of the C-shaped arc mover. The inchworm piezoelectric drive module on the outer arc surface is arranged at a position of 0° on the outer arc surface of the C-shaped arc mover, and is used to jointly complete the constraint and guidance of the C-shaped arc mover; wherein: The inner chamfered surface inchworm piezoelectric drive module, the outer surface inchworm piezoelectric drive module and the outer arc surface inchworm piezoelectric drive module are respectively composed of a flexible hinge shell and two piezoelectric stack legs; the flexible hinge shell includes a flexible hinge that provides fixed stiffness to the piezoelectric stack and a shell for fixing the piezoelectric module; the piezoelectric stack legs are respectively composed of a tangential ceramic stack, a normal ceramic stack and a ceramic feeler to achieve normal expansion and contraction and tangential reciprocating motion of the piezoelectric stack legs, and the two piezoelectric stack legs move in an interlaced manner to provide normal constraint force and tangential motion force to the C-shaped arc mover, thereby achieving bearingless arc-guided motion of the C-shaped arc mover along the arc motion direction; The inner chamfered surface inchworm piezoelectric drive module is mounted on the base through a fixed bracket; The outer side inchworm piezoelectric drive module and the outer arc surface inchworm piezoelectric drive module are installed on the base, and a preload adjustment screw is set at the base installation position. The preload installation of the entire bearingless arc piezoelectric motor is achieved by tightening the preload adjustment screw.

2. The bearingless arc-shaped piezoelectric motor according to claim 1, characterized in that: The contact surface between the inner chamfered surface inchworm piezoelectric drive module and the C-shaped arc-shaped mover is a circular arc surface, and the contact antennae between the piezoelectric stack legs in the inner chamfered surface inchworm piezoelectric drive module and the C-shaped arc-shaped mover are arched ceramic antennae; the contact antennae between the outer surface inchworm piezoelectric drive module and the outer arc-shaped inchworm piezoelectric drive module are flat ceramic antennae.

3. The bearingless arc-shaped piezoelectric motor according to claim 1, characterized in that: The C-shaped arc-shaped mover is replaced by a mover with a 45° chamfer on the inner side of the circle, forming a bearingless rotary piezoelectric motor.

4. The bearingless arc-shaped piezoelectric motor according to claim 1, characterized in that: The C-shaped arc-shaped mover is replaced by a straight line mover with a 45° chamfer on the inside, forming a bearingless linear piezoelectric motor.

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