Multi-mode bidirectional motion rotary piezoelectric motor

Abstract

The invention relates to the field of precise driving and positioning, in particular to a multi-mode bidirectional movement rotary piezoelectric motor. Comprising a base, a rotor mechanism, a stator mechanism and a pre-tightening mechanism, the stator mechanism comprises a flexible metal oscillator connected to the pre-tightening sliding block. The flexible metal oscillator comprises a diamond frame of a sheet structure and an elastic metal substrate connected between a set of opposite angles in the diamond frame. The two groups of piezoelectric ceramic pieces are symmetrically fixed on the same side surface of the elastic metal substrate; the motor further comprises a first driving foot and a second driving foot which are fixed to the flexible metal vibrator, the first driving foot and the second driving foot are fixed to the two adjacent corners of the rhombic frame body respectively, and the first driving foot and the second driving foot make contact with the inner ring of the rotor bearing. According to the technical scheme, through the asymmetric structural design, the rhombic flexible metal oscillator can generate two working modes, so that the motor realizes bidirectional rotation under the condition that the voltage and the structure are not changed.

Description

Technical Field

[0001] The present invention relates to the field of precision drive and positioning, and particularly relates to a multi-modal bidirectional motion rotary piezoelectric motor. Background Art

[0002] Piezoelectric motors utilize the inverse piezoelectric effect of piezoelectric ceramics to convert the input electrical signal into the vibration displacement of the vibrator. At present, piezoelectric motors are widely used in processing and manufacturing systems, precision positioning of robots, medical instruments and other fields due to their advantages such as fast response, no electromagnetic interference, and high resolution. There are many structural types of piezoelectric motors, and according to their working principles, they can be mainly divided into ultrasonic motors, inchworm motors and inertial impact motors.

[0003] Inertial impact motors utilize the "stick-slip" of the stator to achieve the micro displacement of the mover, and achieve macroscopic movement or rotation in a step-by-step manner. Inertial impact motors can usually be divided into structurally asymmetric type and signal asymmetric type according to their working principles. The motor has the advantages of simple structure and can achieve long stroke, etc., but the motor usually works in a quasi-static state, with weak output performance, and due to the asymmetric structural design, it can only move unidirectionally, cannot meet the requirements of various working conditions, and cannot work in the resonant state, making it difficult to exert the performance of the motor. Summary of the Invention

[0004] The purpose of the present invention is to overcome the above drawbacks and provide a multi-modal bidirectional motion rotary piezoelectric motor.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions: including a base, a rotor mechanism, a stator mechanism and a pre-tightening mechanism; The stator mechanism includes a flexible metal vibrator connected to a pre-tightening slider. The flexible metal vibrator includes a rhombic frame body in the form of a thin sheet structure and an elastic metal substrate connected between a set of diagonals in the rhombic frame body; it also includes two groups of piezoelectric ceramic sheets, and the two groups of piezoelectric ceramic sheets are symmetrically fixed on the same side of the elastic metal substrate; it also includes a first driving foot and a second driving foot fixed on the flexible metal vibrator. The first driving foot and the second driving foot are respectively fixed at two adjacent corners of the rhombic frame body, and both the first driving foot and the second driving foot are in contact with the inner ring of the rotor bearing; The pre-tightening mechanism is installed in the guiding groove on the upper surface of the base. The pre-tightening mechanism includes a pre-tightening slider, a pre-tightening bolt and a spring. The bolt body of the pre-tightening bolt passes through the pre-tightening slider and is connected to the groove wall of the guiding groove. A spring is sleeved on the pre-tightening bolt, and the pre-tightening slider is fixed to the bottom of the guiding groove by screws.

[0006] The rhombic frame body is an integral structure, including a first flexible sheet, a first connecting block, a second flexible sheet, a second connecting block, a third flexible sheet, a third connecting block, a fourth flexible sheet and a fourth connecting block which are connected in sequence. The first flexible sheet, the second flexible sheet, the third flexible sheet and the fourth flexible sheet are the four sides of the rhombic frame body, and the above flexible sheets are all arc-shaped sheets. The first connecting block, the second connecting block, the third connecting block and the fourth connecting block are the four corners of the rhombic frame body.

[0007] At the included angle formed by the first flexible sheet, the first connecting block and the second flexible sheet, there is a first mass block that fits the shape of the included angle. At the included angle formed by the third flexible sheet, the third connecting block and the fourth flexible sheet, there is a second mass block that fits the shape of the included angle. The masses of the first mass block and the second mass block are different.

[0008] The elastic metal substrate is arranged in the vertical direction, and its two ends are respectively fixed to the second connecting block and the fourth connecting block. On both sides of the middle position of the elastic metal substrate, thin plates are symmetrically arranged. The thin plates are perpendicular to the elastic metal substrate, and the elastic metal substrate and the thin plates are connected by flexible hinges. The elastic metal substrate, the thin plates and the flexible hinges are an integrally formed structure.

[0009] The flexible metal oscillator is connected to the pre-tightening slider through a fixing block. The fixing block is located outside the flexible metal oscillator, and two groups of fixing blocks are symmetrically arranged with the elastic metal substrate as the axis of symmetry. The two groups of fixing blocks are respectively fixed to the second flexible sheet and the third flexible sheet through connecting plates. The bottom surface of the fixing block is lower than the bottom surface of the flexible metal oscillator so that there is a gap between the flexible metal oscillator and the pre-tightening mechanism.

[0010] The first driving foot is connected to the outside of the fourth connecting block, and the second driving foot is connected to the outside of the third connecting block. The end faces of the first driving foot and the second driving foot in contact with the inner ring of the rotor bearing are both arc-shaped surfaces.

[0011] One end of the spring abuts against the bolt head of the pre-tightening bolt, and the other end of the spring abuts against the pre-tightening slider. By adjusting the pre-tightening bolt, the position of the pre-tightening slider in the guiding groove is adjusted, so as to adjust the pre-tightening force between the flexible metal oscillator and the rotor bearing. On the pre-tightening slider and the groove wall of the guiding groove, there are respectively a first threaded hole and a second threaded hole that cooperate with the pre-tightening bolt. On both sides of the first threaded hole, U-shaped grooves are symmetrically arranged. Screws connecting the pre-tightening slider and the base are arranged in the U-shaped grooves.

[0012] The flexible metal oscillator, the first driving foot, the second driving foot, the fixing block, the first mass block, the second mass block and the connecting plate are an integrally formed structure.

[0013] The described rotor mechanism includes a bearing housing fixed above the base and a rotor bearing installed within the bearing housing; the bearing housing is of an annular structure, and its inner wall is provided with a sunk platform for positioning and installing the rotor bearing, and the rotor bearing is placed on the sunk platform and the outer ring of the rotor bearing is fixed to the inner wall of the bearing housing.

[0014] The materials of the base, the preloading slider and the bearing housing are 45# steel, the material of the flexible metal oscillator is 65Mn steel, the material of the rotor bearing is bearing steel, the material of the preloading bolt is Q235 steel, and the model of the piezoelectric ceramic sheet is PZT-4 type.

[0015] The beneficial technical effects of the present invention are as follows: 1. The present invention adopts the asymmetric principle in structure, utilizes the stick-slip effect of the cam-shaped driving foot to realize the displacement of the rotor bearing, and realizes the bidirectional rotation of the mover clockwise and counterclockwise through the two-order modes of the flexible metal oscillator.

[0016] 2. The piezoelectric motor of the present invention operates in the resonant state and has multiple working modes. The piezoelectric motor can move clockwise in the first-order mode, with a movement speed of 440.7 mrad / s, a resolution of 77.6 μrad, and a load of 129 N·mm. It moves counterclockwise in the second-order mode, with a movement speed of 526.4 mrad / s, a resolution of 4.6 μrad, and a load of 156 N•mm.

[0017] 3. The present invention can achieve different movement speeds and displacement resolutions by adjusting the contact preloading force between the flexible metal oscillator and the rotor bearing, so as to meet the requirements of different loads and different working conditions, and has a wider scope of application. Description of the Drawings

[0018] Figure 1 is the structural schematic diagram of the present invention Figure 1 .

[0019] Figure 2 is the structural schematic diagram of the present invention Figure 2 .

[0020] Figure 3 is the structural schematic diagram of the present invention Figure 3 .

[0021] Figure 4 is the structural schematic diagram of the present invention after removing the rotor mechanism.

[0022] Figure 5 is the structural schematic diagram of the base of the present invention.

[0023] Figure 6 is the structural schematic diagram of the rotor mechanism and the base of the present invention.

[0024] Figure 7 isFigure 6 Schematic diagram of the decomposition structure.

[0025] Figure 8 Schematic diagram of the preloading mechanism of the present invention.

[0026] Figure 9 Schematic diagram of the preloading slider of the present invention.

[0027] Figure 10 Installation schematic diagram of the preloading mechanism and the base of the present invention.

[0028] Figure 11 Schematic diagram of the stator mechanism of the present invention.

[0029] Figure 12 Front view of the stator mechanism of the present invention after removing the piezoelectric ceramic sheet.

[0030] Figure 13 is Figure 12 Enlarged view of part A.

[0031] Figure 14 Front view of the flexible metal oscillator of the present invention.

[0032] Figure 15 Schematic diagram of the structure of the flexible metal oscillator of the present invention.

[0033] Figure 16 Installation schematic diagram of the stator mechanism and the preloading mechanism of the present invention.

[0034] Figure 17 Cooperation schematic diagram of the stator mechanism and the mover mechanism of the present invention.

[0035] Figure 18 Excitation electrical signal diagram of the piezoelectric motor of the present invention.

[0036] Figure 19 Working principle diagram of the piezoelectric motor of the present invention moving clockwise in the first-order mode.

[0037] Figure 20 Working principle diagram of the piezoelectric motor of the present invention moving counterclockwise in the second-order mode.

[0038] The reference signs in the above drawings are: base 1, guiding groove 11, second threaded hole 12, rotor mechanism 2, bearing seat 21, counterbore 211, rotor bearing 22, stator mechanism 3, flexible metal oscillator 31, diamond-shaped frame 311, first flexible sheet 3111, second flexible sheet 3112, third flexible sheet 3113, fourth flexible sheet 3114, first connecting block 3115, second connecting block 3116, third connecting block 3117, fourth connecting block 3118, elastic metal substrate 312, thin plate 313, flexible hinge 314, piezoelectric ceramic sheet 32, first driving foot 33, second driving foot 34, fixing block 35, first mass block 36, second mass block 37, connecting plate 38, pre-tightening mechanism 4, pre-tightening slider 41, first threaded hole 411, U-shaped groove 412, pre-tightening bolt 42, spring 43. Detailed implementation mode

[0039] The present invention will be further described below with reference to the drawings: As Figures 1 to 4 shown, a multi-modal bidirectional motion rotary piezoelectric motor includes a base 1, a rotor mechanism 2, a stator mechanism 3 and a pre-tightening mechanism 4.

[0040] Furthermore, as Figure 5 shown, a guiding groove 11 is formed on the upper surface of the base 1 for installing the pre-tightening mechanism 4.

[0041] Furthermore, as Figure 6 、 Figure 7 shown, the rotor mechanism 2 includes a bearing seat 21 fixed above the base 1 and a rotor bearing 22 installed in the bearing seat 21. The bearing seat 21 is of an annular structure, and a counterbore 211 is provided on its inner wall for positioning and installing the rotor bearing 22. The rotor bearing 22 is placed on the counterbore 211 and the outer ring of the rotor bearing 22 is fixed to the inner wall of the bearing seat 21.

[0042] Furthermore, as Figure 11 shown, the stator mechanism 3 includes a flexible metal oscillator 31, two groups of piezoelectric ceramic sheets 32, a first driving foot 33, a second driving foot 34, a fixing block 35, a first mass block 36, a second mass block 37 and a connecting plate 38, wherein: the flexible metal oscillator 31, the first driving foot 33, the second driving foot 34, the fixing block 35, the first mass block 36, the second mass block 37 and the connecting plate 38 are of an integrally formed structure.

[0043] For the convenience of explaining the structural relationship of each component, Figure 14 、 Figure 15 the structure of the stator mechanism 3 is disassembled into each component for description. In practice, all components of the stator mechanism 3 except the piezoelectric ceramic sheets 32 are of an integral structure.

[0044] Specifically, as Figure 11 、Figure 14 , Figure 15 As shown in Figure 15 , the flexible metal oscillator 31 includes a rhombic frame 311 with a thin sheet structure and an elastic metal substrate 312 connected between a set of diagonals in the rhombic frame 311. The rhombic frame 311 is an integral structure, including a first flexible sheet 3111, a first connecting block 3115, a second flexible sheet 3112, a second connecting block 3116, a third flexible sheet 3113, a third connecting block 3117, a fourth flexible sheet 3114, and a fourth connecting block 3118 connected in sequence. The first flexible sheet 3111, the second flexible sheet 3112, the third flexible sheet 3113, and the fourth flexible sheet 3114 are the four sides of the rhombic frame 311, and the above flexible sheets are all arc-shaped sheets. The first connecting block 3115, the second connecting block 3116, the third connecting block 3117, and the fourth connecting block 3118 are the four corners of the rhombic frame 311. The flexible metal oscillator 31 is connected to the pre-tightening slider 41 through the fixing block 35.

[0045] Specifically, as Figure 12 , Figure 13 shown in Figure 13 , the elastic metal substrate 312 is arranged vertically, and its two ends are respectively fixed to the second connecting block 3116 and the fourth connecting block 3118. Thin plates 313 are symmetrically arranged on both sides of the middle position of the elastic metal substrate 312. The thin plates 313 are perpendicular to the elastic metal substrate 312, and the elastic metal substrate 312 and the thin plates 313 are connected through flexible hinges 314. The elastic metal substrate 312, the thin plates 313, and the flexible hinges 314 are an integrally formed structure. Two groups of piezoelectric ceramic sheets 32 are symmetrically fixed on the same side of the elastic metal substrate 312. The symmetrically arranged thin plates 313 are equivalent to a pair of mass blocks, which are used to amplify the amplitude of the up-and-down vibration of the piezoelectric ceramic sheets 32. The flexible hinge 314 in this embodiment is a bilateral symmetric straight circular structure, and the vibration amplitude of the elastic metal substrate 312 is amplified by making circular cuts.

[0046] Specifically, as Figure 17 shown in Figure 17 , the first driving foot 33 and the second driving foot 34 are fixed on the flexible metal oscillator 31, and both the first driving foot 33 and the second driving foot 34 are in contact with the inner ring of the rotor bearing 22. Preferably, the end faces of the first driving foot 33 and the second driving foot 34 in contact with the inner ring of the rotor bearing 22 are both arc-shaped surfaces. The first driving foot 33 and the second driving foot 34 are respectively fixed at two adjacent corners of the rhombic frame 311, that is, the first driving foot 33 is connected to the outside of the fourth connecting block 3118, and the second driving foot 34 is connected to the outside of the third connecting block 3117.

[0047] Specifically, as Figure 14 , Figure 15As shown, at the angle formed by the first flexible sheet 3111, the first connecting block 3115, and the second flexible sheet 3112, there is a first mass block 36 that fits the shape of the angle. At the angle formed by the third flexible sheet 3113, the third connecting block 3117, and the fourth flexible sheet 3114, there is a second mass block 37 that fits the shape of the angle. The masses of the first mass block 36 and the second mass block 37 are different. The functions of the first mass block 36 and the second mass block 37 are to increase the driving force.

[0048] Specifically, as Figure 16 shown, the fixed block 35 is located outside the flexible metal oscillator 31, and two groups of fixed blocks 35 are symmetrically arranged with the elastic metal substrate 312 as the axis of symmetry. The two groups of fixed blocks 35 are respectively fixed to the second flexible sheet 3112 and the third flexible sheet 3113 through the connecting plate 38. The fixed block 35 and the connecting plate 38 together play a fixing role. The bottom surface of the fixed block 35 is lower than the bottom surface of the flexible metal oscillator 31 so that there is a gap between the flexible metal oscillator 31 and the pre-tightening mechanism 4 to prevent interference between the two.

[0049] Assume that the elastic metal substrate 312 is in the Y-axis direction and the thin plate 313 is in the X-axis direction. Then the two groups of fixed blocks 35 in this embodiment are equivalent to being arranged on one side of the X-axis and are not symmetrically arranged. This arrangement method plays a hindering role in the first-order working mode of the piezoelectric motor, causing the second driving foot 34 to swing asymmetrically in the Y-axis direction, and then generating a clockwise elliptical motion in one cycle. In this embodiment, the first mass block 36 and the second mass block 37 are equivalent to being arranged on both sides of the Y-axis, and the masses of the first mass block 36 and the second mass block 37 are different. This arrangement method can cause the first driving foot 33 to swing asymmetrically in the X-axis direction in the second-order working mode of the piezoelectric motor, and then generate a counterclockwise elliptical motion in one cycle.

[0050] Furthermore, as Figure 8 、 Figure 9 、 Figure 10As shown in the figure, the preloading mechanism 4 includes a preloading slider 41, a preloading bolt 42 and a spring 43. The body part of the preloading bolt 42 penetrates through the preloading slider 41 and is connected to the groove wall of the guiding groove 11. A spring 43 is sleeved on the preloading bolt 42. One end of the spring 43 abuts against the head part of the preloading bolt 42, and the other end of the spring 43 abuts against the preloading slider 41. By adjusting the screwing-in length of the preloading bolt 42, the position of the preloading slider 41 in the guiding groove 11 is adjusted, so as to adjust the preloading force between the flexible metal oscillator 31 and the rotor bearing 22. After the adjustment is completed, the preloading slider 41 is fixed to the bottom of the guiding groove 11 by screws to lock the preloading force. Specifically, a first threaded hole 411 and a second threaded hole 12 that are matched with the preloading bolt 42 are respectively provided on the preloading slider 41 and the groove wall of the guiding groove 11. U-shaped grooves 412 are symmetrically arranged on both sides of the first threaded hole 411, and screws connecting the preloading slider 41 and the base 1 are arranged in the U-shaped grooves 412.

[0051] Furthermore, the materials of the base 1, the preloading slider 41 and the bearing seat 21 of the present invention are 45# steel, the material of the flexible metal oscillator 31 is 65Mn steel, the material of the rotor bearing 22 is bearing steel, the material of the preloading bolt 42 is Q235 steel, and the model of the piezoelectric ceramic sheet 32 is PZT-4 type.

[0052] The working principle of the present invention is as follows: As Figure 18 shown in the figure, during operation, a first-order sine (542 Hz) excitation signal is applied to a pair of piezoelectric ceramic sheets 32 on the elastic metal substrate 312. The elastic metal substrate 312 will reciprocally swing in the positive and negative directions of the X axis within one cycle, and further drive the second driving foot 34 of the flexible metal oscillator 31 to generate a clockwise elliptical motion. Under the action of the second driving foot 34, the inner ring of the rotor bearing 22 will rotate clockwise. A second-order sine (1280 Hz) excitation signal is applied to a pair of piezoelectric ceramic sheets 32 on the elastic metal substrate 312. The elastic metal substrate 312 will generate clockwise and counterclockwise torsion within one cycle, and further drive the first driving foot 33 of the flexible metal oscillator 31 to generate a counterclockwise elliptical motion. Under the action of the first driving foot 33, the inner ring of the rotor bearing 22 will rotate counterclockwise, so as to realize the clockwise and counterclockwise bidirectional continuous rotation of the piezoelectric motor in different working modes.

[0053] As Figure 19 shown in the figure, within the time t0 - t1, the piezoelectric ceramic sheet 32 swings from the initial position to the right limit position, and the second driving foot 34 moves downward to the right. Under the action of the static friction force, the rotor bearing 22 rotates clockwise by an angle θ1.

[0054] During the time period from t1 to t2, the piezoelectric ceramic sheet 32 swings from the right limit position to the initial position, and the second driving foot 34 moves upward and to the left. Since the radius vector of the driving foot gradually decreases, relative slip occurs between the flexible metal oscillator 31 and the rotor bearing 22, so the counterclockwise rotation angle is relatively small. Under the action of dynamic friction, the rotor bearing 22 rotates counterclockwise by an angle θ2.

[0055] During the time period from t2 to t3, the piezoelectric ceramic sheet 32 swings from the initial position to the left limit position, and the second driving foot 34 continues to move upward and to the left. At this time, the rotor bearing 22 gradually disengages from the flexible metal oscillator 31, and the rotor bearing 22 is in a stationary state.

[0056] During the time period from t3 to t4, the piezoelectric ceramic sheet 32 swings from the left limit position to the initial position, and the second driving foot 34 moves downward and to the right. At this time, the rotor bearing 22 gradually comes into contact with the flexible metal oscillator 31, but the rotor bearing 22 does not rotate.

[0057] The above four steps are the specific working process of the piezoelectric motor within one cycle of the first-order resonance excitation voltage signal. During this process, the motor completes a clockwise rotation of △θ = θ1 - θ2 in one working cycle. Repeating this process can achieve continuous unidirectional movement of the piezoelectric motor.

[0058] As Figure 20 shown, during the time period from t0 to t1, the piezoelectric ceramic sheet 32 twists counterclockwise from the initial position to the limit position, and the upper driving foot 311 moves upward and to the left. Under the action of static friction, the bearing 42 rotates counterclockwise by an angle θ3.

[0059] During the time period from t1 to t2, the piezoelectric ceramic sheet 32 twists clockwise from the limit position to the initial position, and the first driving foot 33 moves downward and to the right. Since the radius vector of the driving foot gradually decreases, relative slip occurs between the flexible metal oscillator 31 and the rotor bearing 22, so the clockwise rotation angle is relatively small. Under the action of dynamic friction, the rotor bearing 22 rotates clockwise by an angle θ4.

[0060] During the time period from t2 to t3, the piezoelectric ceramic sheet 32 twists clockwise from the initial position to the limit position, the first driving foot 33 continues to move downward and to the right, and the rotor bearing 22 gradually disengages from the flexible metal oscillator 31, and the rotor bearing 22 is in a stationary state.

[0061] During the time period from t3 to t4, the piezoelectric ceramic sheet 32 twists counterclockwise from the limit position to the initial position, the first driving foot 33 moves upward and to the left, and the rotor bearing 22 gradually comes into contact with the flexible metal oscillator 31, but the rotor bearing 22 does not rotate.

[0062] The above four steps are the specific working process of the piezoelectric motor within one cycle of the second-order resonance excitation voltage signal. During this process, the motor completes one cycle of counterclockwise rotation of Δθ = θ3 - θ4. Repeating this process can achieve continuous unidirectional movement of the motor.

[0063] During operation, the contact pre-tightening force between the flexible metal oscillator and the rotor bearing can be adjusted according to specific conditions to achieve different movement speeds and displacement resolutions, so as to meet the requirements of different loads and working conditions, and make it have a wider range of applications.

[0064] The piezoelectric motor of the present invention can rotate clockwise in the first-order mode, with a movement speed of 440.7 mrad / s, a resolution of 77.6 μrad, and a load of 129 N·mm. It rotates counterclockwise in the second-order mode, with a movement speed of 526.4 mrad / s, a resolution of 4.6 μrad, and a load of 156 N·mm.

[0065] The embodiments described above are only used to describe the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A multimodal bidirectional motion rotary piezoelectric motor, characterized in that: It includes a base (1), a rotor mechanism (2), a stator mechanism (3) and a preloading mechanism (4); The stator mechanism (3) includes a flexible metal oscillator (31) connected to a preloading slider (41). The flexible metal oscillator (31) includes a rhombic frame body (311) in the form of a thin sheet structure and an elastic metal substrate (312) connected between a set of diagonals in the rhombic frame body (311); It also includes two groups of piezoelectric ceramic sheets (32), and the two groups of piezoelectric ceramic sheets (32) are symmetrically fixed on the same side of the elastic metal substrate (312); It also includes a first driving foot (33) and a second driving foot (34) fixed on the flexible metal oscillator (31). The first driving foot (33) and the second driving foot (34) are respectively fixed at two adjacent corners of the rhombic frame body (311), and both the first driving foot (33) and the second driving foot (34) are in contact with the inner ring of the rotor bearing (22); The preloading mechanism is installed in a guiding groove (11) on the upper surface of the base (1). The preloading mechanism (4) includes a preloading slider (41), a preloading bolt (42) and a spring (43). The bolt body of the preloading bolt (42) penetrates through the preloading slider (41) and is connected to the groove wall of the guiding groove (11). A spring (43) is sleeved on the preloading bolt (42), and the preloading slider (41) is fixed to the bottom of the guiding groove (11) by screws.

2. The multimodal bidirectional motion rotary piezoelectric motor according to claim 1, characterized in that: The rhombic frame body (311) is an integral structure, including a first flexible sheet (3111), a first connecting block (3115), a second flexible sheet (3112), a second connecting block (3116), a third flexible sheet (3113), a third connecting block (3117), a fourth flexible sheet (3114) and a fourth connecting block (3118) connected in sequence. The first flexible sheet (3111), the second flexible sheet (3112), the third flexible sheet (3113) and the fourth flexible sheet (3114) are the four sides of the rhombic frame body (311), and the above flexible sheets are all arc-shaped sheets. The first connecting block (3115), the second connecting block (3116), the third connecting block (3117) and the fourth connecting block (3118) are the four corners of the rhombic frame body (311).

3. The multimodal bidirectional motion rotary piezoelectric motor according to claim 2, wherein: A first mass block (36) matching the shape of the included angle is provided at the included angle formed by the first flexible sheet (3111), the first connecting block (3115) and the second flexible sheet (3112). A second mass block (37) matching the shape of the included angle is provided at the included angle formed by the third flexible sheet (3113), the third connecting block (3117) and the fourth flexible sheet (3114). The masses of the first mass block (36) and the second mass block (37) are different.

4. The multimodal bidirectional motion rotary piezoelectric motor according to claim 2, wherein: The elastic metal substrate (312) is arranged vertically, with its two ends fixed to the second connecting block (3116) and the fourth connecting block (3118) respectively. On both sides of the middle position of the elastic metal substrate (312), thin plates (313) are symmetrically arranged. The thin plates (313) are perpendicular to the elastic metal substrate (312), and the elastic metal substrate (312) is connected to the thin plates (313) through flexible hinges (314). The elastic metal substrate (312), the thin plates (313) and the flexible hinges (314) are of an integrally formed structure.

5. The multimodal bidirectional motion rotary piezoelectric motor according to claim 3, characterized in that: The flexible metal oscillator (31) is connected to the pre-tightening slider (41) through a fixing block (35). The fixing block (35) is located outside the flexible metal oscillator (31), and two groups of fixing blocks (35) are symmetrically arranged with the elastic metal substrate (312) as the axis of symmetry. The two groups of fixing blocks (35) are respectively fixed to the second flexible sheet (3112) and the third flexible sheet (3113) through connecting plates (38). The bottom surface of the fixing block (35) is lower than the bottom surface of the flexible metal oscillator (31) so as to leave a gap between the flexible metal oscillator (31) and the pre-tightening mechanism (4).

6. The multimodal bidirectional motion rotary piezoelectric motor according to claim 1, wherein: The first driving foot (33) is connected to the outside of the fourth connecting block (3118), and the second driving foot (34) is connected to the outside of the third connecting block (3117). The end faces of the first driving foot (33) and the second driving foot (34) in contact with the inner ring of the rotor bearing (22) are both arc-shaped.

7. The multimodal bidirectional motion rotary piezoelectric motor according to claim 1, wherein: One end of the spring (43) abuts against the bolt head of the pre-tightening bolt (42), and the other end of the spring (43) abuts against the pre-tightening slider (41). By adjusting the pre-tightening bolt (42), the position of the pre-tightening slider (41) in the guide groove (11) is adjusted, so as to adjust the pre-tightening force between the flexible metal oscillator (31) and the rotor bearing (22); The pre-tightening slider (41) and the groove wall of the guide groove (11) are respectively provided with a first threaded hole (411) and a second threaded hole (12) that cooperate with the pre-tightening bolt (42). On both sides of the first threaded hole (411), U-shaped grooves (412) are symmetrically provided. Screws connecting the pre-tightening slider (41) and the base (1) are provided in the U-shaped grooves (412).

8. The multimodal bidirectional motion rotary piezoelectric motor according to claim 5, characterized in that: The flexible metal oscillator (31), the first driving foot (33), the second driving foot (34), the fixing block (35), the first mass block (36), the second mass block (37) and the connecting plate (38) are of an integrally formed structure.

9. The multimodal bidirectional motion rotary piezoelectric motor according to claim 1, characterized in that: The rotor mechanism (2) includes a bearing seat (21) fixed above the base (1) and a rotor bearing (22) installed in the bearing seat (21); the bearing seat (21) is of an annular structure, and its inner wall is provided with a sunk platform (211) for positioning and installing the rotor bearing (22). The rotor bearing (22) is placed on the sunk platform (211), and the outer ring of the rotor bearing (22) is fixed to the inner wall of the bearing seat (21).

10. The multimodal bidirectional motion rotary piezoelectric motor according to claim 1, characterized in that: The materials of the base (1), pre-tightening slider (41) and bearing block (21) are 45# steel, the material of the flexible metal oscillator (31) is 65Mn steel, the material of the rotor bearing (22) is bearing steel, the material of the pre-tightening bolt (42) is Q235 steel, and the model of the piezoelectric ceramic sheet (32) is PZT-4 type.

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