A multi-modal bidirectional motion rotary piezoelectric motor

Abstract

The present invention relates to the field of precision driving and positioning, and specifically to a multi-modal bidirectional motion rotary piezoelectric motor. It includes 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 rhombus frame with a thin sheet structure and an elastic metal substrate connected between a set of diagonal corners in the rhombus frame; it also includes two groups of piezoelectric ceramic sheets, 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 to two adjacent corners of the rhombus frame, and the first driving foot and the second driving foot are both in contact with the inner ring of the rotor bearing. It can be seen from the above technical solution that through the asymmetric structural design, the rhombus-shaped flexible metal vibrator can generate two working modes, so that the motor can achieve bidirectional rotation without changing the voltage and structure.

Description

Technical Field

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

[0002] Piezoelectric motors utilize the inverse piezoelectric effect of piezoelectric ceramics to convert input electrical signals into the vibration displacement of a vibrator. Currently, piezoelectric motors are widely used in manufacturing systems, precision robotic positioning, and medical devices due to their fast response, lack of electromagnetic interference, and high resolution. Piezoelectric motors come in a variety of structural types, but can be broadly categorized by their operating principle into ultrasonic motors, inchworm motors, and inertial impact motors.

[0003] Inertial impact motors utilize the stick-slip behavior of the stator to achieve micro-displacements of the rotor, achieving macroscopic movement or rotation through stepping. Based on their operating principle, inertial impact motors can be generally categorized as structurally asymmetric and signal-asymmetric. While these motors offer advantages such as a simple structure and the ability to achieve long strokes, they typically operate in a quasi-static state, resulting in weak output performance. Furthermore, due to their asymmetric design, they are limited to unidirectional motion, making them incapable of meeting diverse operating requirements. Furthermore, they cannot operate in a resonant state, hindering their full performance. Summary of the Invention

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

[0005] To achieve the above-mentioned purpose, the present invention adopts the following technical solution: comprising a base, a rotor mechanism, a stator mechanism and a pre-tightening mechanism;

[0006] The stator mechanism includes a flexible metal vibrator connected to the preload slider, the flexible metal vibrator comprising a rhombus-shaped frame with a thin sheet structure and an elastic metal substrate connected between a set of diagonal corners of the rhombus frame; two groups of piezoelectric ceramic sheets are symmetrically fixed on the same side of the elastic metal substrate; and a first driving foot and a second driving foot are fixed to the flexible metal vibrator, the first driving foot and the second driving foot are respectively fixed to two adjacent corners of the rhombus frame, and the first driving foot and the second driving foot are both in contact with the inner ring of the rotor bearing.

[0007] The pre-tightening mechanism is installed in the guide 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 guide groove. A spring is sleeved on the pre-tightening bolt, and the pre-tightening slider is fixed to the bottom of the guide groove by a screw.

[0008] The diamond-shaped frame is an integrated 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 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 diamond-shaped frame, and the above-mentioned 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 diamond-shaped frame.

[0009] A first mass block that matches the shape of the angle is provided at the angle formed by the first flexible sheet, the first connecting block and the second flexible sheet, and a second mass block that matches the shape of the angle is provided at the angle formed by the third flexible sheet, the third connecting block and the fourth flexible sheet, and the masses of the first mass block and the second mass block are different.

[0010] The elastic metal substrate is arranged in a vertical direction, and its two ends are fixed to the second connecting block and the fourth connecting block respectively. Thin plates are symmetrically arranged on both sides of the middle position of the elastic metal substrate. The thin plates are perpendicular to the elastic metal substrate, and the elastic metal substrate and the thin plates are connected by a flexible hinge. The elastic metal substrate, thin plates and flexible hinges are an integrally formed structure.

[0011] The flexible metal vibrator is connected to the pre-tightening slider through a fixing block. The fixing block is located outside the flexible metal vibrator, and two groups of fixing blocks are symmetrically arranged with the elastic metal substrate as the symmetry axis. 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 vibrator so that a gap is left between the flexible metal vibrator and the pre-tightening mechanism.

[0012] 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 surfaces of the first driving foot and the second driving foot that contact the inner ring of the rotor bearing are both arc surfaces.

[0013] 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. The position of the pre-tightening slider in the guide groove is adjusted by adjusting the pre-tightening bolt, thereby adjusting the pre-tightening force between the flexible metal vibrator and the rotor bearing.

[0014] The pre-tightening slider and the groove wall of the guide groove are respectively provided with a first threaded hole and a second threaded hole that match the pre-tightening bolt. U-shaped grooves are symmetrically provided on both sides of the first threaded hole. Screws connecting the pre-tightening slider and the base are provided in the U-shaped grooves.

[0015] The flexible metal vibrator, 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.

[0016] The rotor mechanism includes a bearing seat fixed above the base and a rotor bearing installed in the bearing seat; the bearing seat is an annular structure, and its inner wall is provided with a sinking platform for positioning and installing the rotor bearing. The rotor bearing is placed on the sinking platform and the outer ring of the rotor bearing is fixed to the inner wall of the bearing seat.

[0017] The base, pre-tightening slider and bearing seat are made of 45# steel, the flexible metal vibrator is made of 65Mn steel, the rotor bearing is made of bearing steel, the pre-tightening bolt is made of Q235 steel, and the piezoelectric ceramic piece is of PZT-4 type.

[0018] The beneficial technical effects of the present invention are:

[0019] 1. The present invention adopts an asymmetric principle in structure, utilizes the stick-slip effect of a cam-shaped driving foot to achieve the displacement of the rotor bearing, and realizes the clockwise and counterclockwise bidirectional rotation of the mover through the two-order modes of the flexible metal vibrator.

[0020] 2. The piezoelectric motor of the present invention operates in a resonant state and has multiple operating modes. In the first-order mode, the piezoelectric motor can move clockwise with a movement speed of 440.7 mrad / s, a resolution of 77.6 μrad, and a load of 129 N.mm. In the second-order mode, it can move counterclockwise with a movement speed of 526.4 mrad / s, a resolution of 4.6 μrad, and a load of 156 N.mm.

[0021] 3. The present invention can achieve different motion speeds and displacement resolutions by adjusting the contact preload force between the flexible metal vibrator and the rotor bearing to meet the needs of different loads and different working conditions, and has a wider range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the structure of the present invention Figure 1 .

[0023] Figure 2 This is a schematic diagram of the structure of the present invention Figure 2 .

[0024] Figure 3 This is a schematic diagram of the structure of the present invention Figure 3 .

[0025] Figure 4 It is a structural schematic diagram of the present invention after removing the rotor mechanism.

[0026] Figure 5 It is a structural schematic diagram of the base of the present invention.

[0027] Figure 6 It is a structural schematic diagram of the rotor mechanism and the base of the present invention.

[0028] Figure 7 yes Figure 6 Schematic diagram of the decomposition structure.

[0029] Figure 8 It is a structural schematic diagram of the pre-tightening mechanism of the present invention.

[0030] Figure 9 It is a structural schematic diagram of the pre-tightening slider of the present invention.

[0031] Figure 10 It is a schematic diagram of the installation of the pre-tightening mechanism and the base of the present invention.

[0032] Figure 11 It is a structural schematic diagram of the stator mechanism of the present invention.

[0033] Figure 12 This is a front view of the stator mechanism of the present invention after removing the piezoelectric ceramic sheet.

[0034] Figure 13 yes Figure 12 Magnified view of part A.

[0035] Figure 14 It is a front view of the flexible metal vibrator of the present invention.

[0036] Figure 15 It is a structural schematic diagram of the flexible metal vibrator of the present invention.

[0037] Figure 16 It is a schematic diagram of the installation of the stator mechanism and the pre-tightening mechanism of the present invention.

[0038] Figure 17 It is a schematic diagram of the coordination between the stator mechanism and the mover mechanism of the present invention.

[0039] Figure 18 This is a diagram of the excitation electrical signal of the piezoelectric motor of the present invention.

[0040] Figure 19 This is a working principle diagram of the piezoelectric motor of the present invention moving clockwise in the first-order mode.

[0041] Figure 20 This is a diagram showing the working principle of the piezoelectric motor of the present invention moving counterclockwise in the second-order mode.

[0042] The marks in the above drawings are: base 1, guide groove 11, second threaded hole 12, rotor mechanism 2, bearing seat 21, sinker 211, rotor bearing 22, stator mechanism 3, flexible metal vibrator 31, diamond 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, fixed 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 DESCRIPTION

[0043] The present invention will be further described below with reference to the accompanying drawings:

[0044] like Figures 1 to 4 A multi-modal bidirectional motion rotary piezoelectric motor shown includes a base 1 , a rotor mechanism 2 , a stator mechanism 3 and a preload mechanism 4 .

[0045] Further, such as Figure 5 As shown, a guide groove 11 is provided on the upper surface of the base 1 for installing the pre-tightening mechanism 4 .

[0046] Further, such as Figure 6 、 Figure 7 As shown, the rotor mechanism 2 includes a bearing seat 21 fixed above the base 1 and a rotor bearing 22 mounted in the bearing seat 21. The bearing seat 21 is an annular structure with a recessed platform 211 on its inner wall for positioning and mounting the rotor bearing 22. The rotor bearing 22 is placed on the recessed platform 211, and the outer ring of the rotor bearing 22 is fixed to the inner wall of the bearing seat 21.

[0047] Further, such as Figure 11 As shown, the stator mechanism 3 includes a flexible metal vibrator 31, two groups of piezoelectric ceramic sheets 32, a first driving foot 33, a second driving foot 34, a fixed block 35, a first mass block 36, a second mass block 37 and a connecting plate 38, wherein: the flexible metal vibrator 31, the first driving foot 33, the second driving foot 34, the fixed block 35, the first mass block 36, the second mass block 37 and the connecting plate 38 are an integrally formed structure.

[0048] In order to explain the structural relationship of each component, Figure 14 、 Figure 15 The structure of the stator mechanism 3 is separated into various components for explanation. In practice, all components of the stator mechanism 3 except the piezoelectric ceramic sheet 32 ​​are an integrated structure.

[0049] Specifically, such as Figure 11 、 Figure 14 、 Figure 15 As shown, the flexible metal vibrator 31 includes a rhombus-shaped frame 311 with a thin sheet structure and an elastic metal substrate 312 connected between a set of diagonal corners of the rhombus frame 311. The rhombus frame 311 is an integrated 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 rhombus frame 311, and all of these flexible sheets are 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 rhombus frame 311. The flexible metal vibrator 31 is connected to the preload slider 41 via a fixing block 35.

[0050] Specifically, such as Figure 12 、 Figure 13 As shown, the elastic metal substrate 312 is arranged vertically, with its ends fixed to the second connecting block 3116 and the fourth connecting block 3118, respectively. Thin plates 313 are symmetrically arranged on either side of the center of the elastic metal substrate 312. The thin plates 313 are perpendicular to the elastic metal substrate 312 and connected to the thin plates 313 via a flexible hinge 314. The elastic metal substrate 312, thin plates 313, and flexible hinge 314 form an integral structure, with two sets of piezoelectric ceramic sheets 32 symmetrically fixed to the same side of the elastic metal substrate 312. The symmetrically arranged thin plates 313 act as a pair of mass blocks, amplifying the amplitude of the vertical vibration of the piezoelectric ceramic sheets 32. The flexible hinge 314 in this embodiment is a bilaterally symmetrical straight circular structure, which amplifies the vibration amplitude of the elastic metal substrate 312 by creating a circular incision.

[0051] Specifically, such as Figure 17 As shown, the first driving foot 33 and the second driving foot 34 are fixed to the flexible metal vibrator 31, and both the first driving foot 33 and the second driving foot 34 contact the inner ring of the rotor bearing 22. Preferably, the end surfaces of the first driving foot 33 and the second driving foot 34 that contact the inner ring of the rotor bearing 22 are both arcuate surfaces. The first driving foot 33 and the second driving foot 34 are respectively fixed to two adjacent corners of the diamond-shaped 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.

[0052] Specifically, such as Figure 14 、 Figure 15As shown, a first mass block 36 that matches the shape of the angle is provided at the angle formed by the first flexible sheet 3111, the first connecting block 3115, and the second flexible sheet 3112. A second mass block 37 that matches the shape of the angle is provided at the angle formed by the third flexible sheet 3113, the third connecting block 3117, and the fourth flexible sheet 3114. The first mass block 36 and the second mass block 37 have different masses. The function of the first mass block 36 and the second mass block 37 is to increase the driving force.

[0053] Specifically, such as Figure 16 As shown, the fixing blocks 35 are located outside the flexible metal vibrator 31. Two sets of fixing blocks 35 are symmetrically arranged around the elastic metal substrate 312. The two sets of fixing blocks 35 are respectively fixed to the second flexible sheet 3112 and the third flexible sheet 3113 via a connecting plate 38. The fixing blocks 35 and the connecting plate 38 function as a whole to secure the flexible metal vibrator 31. The bottom surface of the fixing blocks 35 is lower than the bottom surface of the flexible metal vibrator 31, leaving a gap between the flexible metal vibrator 31 and the preload mechanism 4 to prevent interference between the two.

[0054] Assuming the elastic metal substrate 312 is oriented along the Y-axis and the thin plate 313 is oriented along the X-axis, the two sets of fixed blocks 35 in this embodiment are equivalent to being arranged on one side of the X-axis, asymmetrically. This arrangement acts as an obstacle in the piezoelectric motor's first-order operating mode, causing the second driving foot 34 to swing asymmetrically along the Y-axis, thereby generating clockwise elliptical motion within a single cycle. In this embodiment, the first mass block 36 and the second mass block 37 are equivalent to being arranged on either side of the Y-axis, and their masses differ. This arrangement causes the first driving foot 33 to swing asymmetrically along the X-axis in the piezoelectric motor's second-order operating mode, thereby generating counterclockwise elliptical motion within a single cycle.

[0055] Further, such as Figure 8 、 Figure 9 、 Figure 10As shown, the pre-tightening mechanism 4 includes a pre-tightening slider 41, a pre-tightening bolt 42, and a spring 43. The bolt body of the pre-tightening bolt 42 passes through the pre-tightening slider 41 and is connected to the groove wall of the guide groove 11. The spring 43 is sleeved on the pre-tightening bolt 42, 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. The position of the pre-tightening slider 41 in the guide groove 11 is adjusted by adjusting the screw-in length of the pre-tightening bolt 42, thereby adjusting the pre-tightening force between the flexible metal vibrator 31 and the rotor bearing 22. After the adjustment is completed, the pre-tightening slider 41 is fixed to the bottom of the guide groove 11 by screws to lock the pre-tightening force. Specifically, 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. U-shaped grooves 412 are symmetrically provided on both sides of the first threaded hole 411. The U-shaped grooves 412 are provided with screws that connect the pre-tightening slider 41 to the base 1.

[0056] Furthermore, the material of the base 1, pre-tightening slider 41 and bearing seat 21 of the present invention is 45# steel, the material of the flexible metal vibrator 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 piece 32 is PZT-4.

[0057] The working principle of the present invention is as follows:

[0058] like Figure 18 As shown, during operation, a first-order sinusoidal (542 Hz) excitation signal is applied to the pair of piezoelectric ceramic plates 32 on the elastic metal substrate 312. The elastic metal substrate 312 will oscillate back and forth along the positive and negative directions of the X-axis within one cycle, thereby driving the second driving foot 34 of the flexible metal vibrator 31 to produce clockwise elliptical motion. Under the action of the second driving foot 34, the inner ring of the rotor bearing 22 will rotate clockwise. When a second-order sinusoidal (1280 Hz) excitation signal is applied to the pair of piezoelectric ceramic plates 32 on the elastic metal substrate 312, the elastic metal substrate 312 will produce clockwise and counterclockwise torsional motion within one cycle, thereby driving the first driving foot 33 of the flexible metal vibrator 31 to produce counterclockwise elliptical motion. Under the action of the first driving foot 33, the inner ring of the rotor bearing 22 will rotate counterclockwise, thereby achieving continuous clockwise and counterclockwise bidirectional rotation of the piezoelectric motor in different operating modes.

[0059] like Figure 19 As shown, during the time period t0 to t1, the piezoelectric ceramic piece 32 swings from the initial position to the right limit position, and the second driving foot 34 moves to the lower right. Under the action of the static friction force, the rotor bearing 22 rotates clockwise by an angle θ1.

[0060] Between time t1 and t2, the piezoelectric ceramic disc 32 swings from its right limit position to its initial position, and the second driving foot 34 moves upward and leftward. As the driving foot's radial direction gradually decreases, relative slippage occurs between the flexible metal vibrator 31 and the rotor bearing 22, resulting in a small counterclockwise rotation angle. Under the influence of kinetic friction, the rotor bearing 22 rotates counterclockwise by an angle θ2.

[0061] During the time period t2 to t3, the piezoelectric ceramic piece 32 swings from the initial position to the left limit position, and the second driving foot 34 continues to move upward to the left. At this time, the rotor bearing 22 gradually separates from the flexible metal vibrator 31, and the rotor bearing 22 is in a stationary state.

[0062] During time t3 to t4, the piezoelectric ceramic piece 32 swings from the left limit position to the initial position, and the second driving foot 34 moves downward to the right. At this time, the rotor bearing 22 gradually contacts the flexible metal vibrator 31, but the rotor bearing 22 does not rotate.

[0063] The above four steps are the specific working process of the piezoelectric motor within a first-order resonant excitation voltage signal cycle. During this process, the motor completes a working cycle of clockwise rotation △θ=θ1-θ2, and this is repeated to achieve continuous unidirectional motion of the piezoelectric motor.

[0064] like Figure 20 As shown, during the time period t0 to t1, the piezoelectric ceramic piece 32 rotates counterclockwise from the initial position to the limit position, and the upper driving foot 311 moves to the upper left. Under the action of static friction, the bearing 42 rotates counterclockwise by an angle θ3.

[0065] Between time t1 and t2, the piezoelectric ceramic disc 32 twists clockwise from its extreme position to its initial position, and the first driving foot 33 moves downward and to the right. As the driving foot's radial direction gradually decreases, relative slippage occurs between the flexible metal vibrator 31 and the rotor bearing 22, resulting in a smaller clockwise rotation angle. Under the action of kinetic friction, the rotor bearing 22 rotates clockwise by an angle θ4.

[0066] During the time period t2 to t3, the piezoelectric ceramic piece 32 twists clockwise from the initial position to the limit position, the first driving foot 33 continues to move to the lower right, the rotor bearing 22 gradually separates from the flexible metal vibrator 31, and the rotor bearing 22 is in a stationary state.

[0067] During the time period t3 to t4, the piezoelectric ceramic piece 32 twists counterclockwise from the extreme position to the initial position, the first driving foot 33 moves to the upper left, and the rotor bearing 22 gradually contacts the flexible metal vibrator 31, but the rotor bearing 22 does not rotate.

[0068] The above four steps are the specific working process of the piezoelectric motor within a second-order resonant excitation voltage signal cycle. During this process, the motor completes a working cycle of counterclockwise rotation △θ=θ3-θ4, and repeats this process to achieve continuous unidirectional motion of the motor.

[0069] During operation, the contact preload force between the flexible metal vibrator and the rotor bearing can be adjusted according to the specific situation to achieve different movement speeds and displacement resolutions to meet the needs of different loads and different working conditions, making it have a wider range of applications.

[0070] The piezoelectric motor of the present invention can move clockwise in the first-order mode with a speed of 440.7 mrad / s, a resolution of 77.6 μrad, and a load of 129 N·mm. It can move counterclockwise in the second-order mode with a speed of 526.4 mrad / s, a resolution of 4.6 μrad, and a load of 156 N·mm.

[0071] The embodiments described above are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A multi-modal bidirectional rotary piezoelectric motor, characterized in that: It comprises a base (1), a rotor mechanism (2), a stator mechanism (3) and a pre-tightening mechanism (4); 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 an annular structure, and its inner wall is provided with a sink (211) for positioning and installing the rotor bearing (22), the rotor bearing (22) is placed on the sink (211) and the outer ring of the rotor bearing (22) is fixed to the inner wall of the bearing seat (21). The stator mechanism (3) includes a flexible metal vibrator (31) connected to a preloaded slider (41), wherein the flexible metal vibrator (31) includes a rhombus frame (311) with a thin sheet structure and an elastic metal substrate (312) connected between a group of diagonal corners in the rhombus frame (311); further includes two groups of piezoelectric ceramic sheets (32), wherein the two groups of piezoelectric ceramic sheets (32) are symmetrically fixed on the same side of the elastic metal substrate (312); further includes a first driving foot (33) and a second driving foot (34) fixed on the flexible metal vibrator (31), wherein the first driving foot (33) and the second driving foot (34) are respectively fixed on two adjacent corners of the rhombus frame (311), and the first driving foot (33) and the second driving foot (34) are both in contact with the inner ring of the rotor bearing (22); The pre-tightening mechanism is installed in the guide groove (11) on the upper surface of the base (1). The pre-tightening mechanism (4) includes a pre-tightening slider (41), a pre-tightening bolt (42) and a spring (43). The bolt body of the pre-tightening bolt (42) passes through the pre-tightening slider (41) and is connected to the groove wall of the guide groove (11). The spring (43) is sleeved on the pre-tightening bolt (42). The pre-tightening slider (41) is fixed to the groove bottom of the guide groove (11) by a screw.

2. The multi-mode bidirectional motion rotary piezoelectric motor according to claim 1, characterized in that: The diamond-shaped frame (311) is an integrated structure, comprising 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 diamond-shaped frame (311), and the above-mentioned 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 diamond-shaped frame (311).

3. The multi-modal bidirectional motion rotary piezoelectric motor according to claim 2, characterized in that: A first mass block (36) matching the shape of the angle is provided at an 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 angle is provided at an angle formed by the third flexible sheet (3113), the third connecting block (3117) and the fourth flexible sheet (3114); the first mass block (36) and the second mass block (37) have different masses.

4. The multi-modal bidirectional motion rotary piezoelectric motor according to claim 2, characterized in that: The elastic metal substrate (312) is arranged in a vertical direction, and its two ends are fixed to the second connecting block (3116) and the fourth connecting block (3118) respectively. 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 by a flexible hinge (314). The elastic metal substrate (312), the thin plates (313) and the flexible hinge (314) are an integrally formed structure.

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

6. The multi-mode bidirectional motion rotary piezoelectric motor according to claim 1, characterized in that: 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 surfaces of the first driving foot (33) and the second driving foot (34) that contact the inner ring of the rotor bearing (22) are both arc surfaces.

7. The multi-mode bidirectional motion rotary piezoelectric motor according to claim 1, characterized in that: 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). The position of the pre-tightening slider (41) in the guide groove (11) is adjusted by adjusting the pre-tightening bolt (42), thereby adjusting the pre-tightening force between the flexible metal vibrator (31) and the rotor bearing (22); The pre-tightening slider (41) and the guide groove (11) are respectively provided with a first threaded hole (411) and a second threaded hole (12) that match the pre-tightening bolt (42). U-shaped grooves (412) are symmetrically provided on both sides of the first threaded hole (411). Screws connecting the pre-tightening slider (41) and the base (1) are provided in the U-shaped grooves (412).

8. The multi-mode bidirectional motion rotary piezoelectric motor according to claim 5, characterized in that: The flexible metal vibrator (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 an integrally formed structure.

9. The multi-mode bidirectional motion rotary piezoelectric motor according to claim 1, characterized in that: The base (1), the pre-tightening slider (41) and the bearing seat (21) are made of 45# steel, the flexible metal vibrator (31) is made of 65Mn steel, the rotor bearing (22) is made of bearing steel, the pre-tightening bolt (42) is made of Q235 steel, and the piezoelectric ceramic piece (32) is of PZT-4 type.

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