Pre-pressure application device and method for traveling wave ultrasonic motor performance test

Abstract

The present invention provides a device and method for accurately applying pre-stress for performance testing of traveling wave ultrasonic motors. The spiral feed of the spiral micrometer in the pre-stress applying device of the present invention pushes the pre-stressing platform to move, and then pushes the flexible pre-stressing head assembly, so that the elastic mechanism in the flexible pre-stressing head assembly is deformed, and pre-stress is applied to the stator. At the same time, a pressure monitoring mechanism is provided to obtain the above pre-stress in real time, and adjust the spiral feed of the spiral micrometer according to the pre-stress, so that the output performance of the traveling wave ultrasonic motor is optimized or the wear law of the friction material provided at the contact point between the stator and the rotor is obtained; the present invention also provides a pre-stress applying method implemented by the above pre-stress applying device; the device and method of the present invention have the advantages of convenient adjustment, accurate and reliable, easy to maintain, and uniform distribution of the applied pre-stress, and can achieve the effect of accurate application of pre-stress while ensuring the simplicity of structure, providing technical support for ultrasonic motor performance testing devices.

Description

Technical Field

[0001] The invention relates to a traveling wave ultrasonic motor testing device and method, in particular to an open pre-pressure controllable rotary traveling wave ultrasonic motor performance testing device and method, belonging to the application field of ultrasonic motor testing technology. Background Art

[0002] In recent years, ultrasonic motors have made great progress. Compared with traditional electromagnetic motors, ultrasonic motors do not rely on electromagnetic media to transfer energy, but use the inverse piezoelectric effect of piezoelectric ceramics. The output performance of the motor is not only related to the stator and rotor structure design, but also affected by the preload. Whether the applied preload is uniform and the size is appropriate will affect the output performance of the motor.

[0003] At present, the research on ultrasonic motor pre-stress at home and abroad mostly adopts the modeling and simulation method. Since the established model ignores too many influencing factors, it cannot truly reflect the impact of pre-stress on the output performance of ultrasonic motor during operation. The introduction of traveling wave ultrasonic motor pre-stress test device abroad is unclear and no detailed reports have been seen; domestic institutions such as Nanjing University of Aeronautics and Astronautics, Tsinghua University, Zhejiang University, Harbin Institute of Technology, etc. have conducted research on traveling wave ultrasonic motor pre-stress application device, but there are still many shortcomings. First, most traveling wave ultrasonic motor pre-stress adjustment adopts closed loading, which is not easy to disassemble. Secondly, due to the serious wear of the motor during operation, the thickness of the friction material will change, so the pre-stress cannot be guaranteed to remain unchanged. Summary of the invention

[0004] The purpose of the present invention is to overcome the above-mentioned defects and provide a device and method for accurately applying pre-stress for performance testing of traveling wave ultrasonic motors. The spiral feed of the spiral micrometer in the pre-stress applying device of the present invention drives the pre-stressing platform to move, and then drives the flexible pre-stressing head assembly, so that the elastic mechanism in the flexible pre-stressing head assembly is deformed, and pre-stress is applied to the stator. At the same time, a pressure monitoring mechanism is provided to obtain the above-mentioned pre-stress in real time, and adjust the spiral feed of the spiral micrometer according to the pre-stress, so as to optimize the output performance of the traveling wave ultrasonic motor or obtain the wear law of the friction material provided at the contact point between the stator and the rotor; the present invention also provides a pre-stressing method implemented by using the above-mentioned pre-stressing device; the device and method of the present invention ensure that the stator of the ultrasonic motor is uniformly stressed, and the effect of accurate application of pre-stress can be achieved while ensuring a simple structure.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] A pre-stress applying device for performance testing of a traveling wave ultrasonic motor, the traveling wave ultrasonic motor comprising a rotor, a stator and a stator seat for fixing the stator, the contact between the stator and the rotor being coated with a friction material, characterized in that the pre-stress applying device comprises a flexible pre-stressing head assembly, a supporting and fixing mechanism, a pre-stressing platform, and a screw micrometer head;

[0007] The supporting and fixing mechanism is used to support the traveling wave ultrasonic motor, the flexible pre-pressing head assembly, the pre-pressing platform and the screw micrometer head which are arranged in sequence, so that the output shaft of the traveling wave ultrasonic motor, the flexible pre-pressing head assembly, the pre-pressing platform and the screw micrometer head are coaxial;

[0008] The flexible preloading head assembly comprises an annular gasket, a screw and an elastic mechanism; the preloading platform is sleeved on the screw micrometer; the annular gasket is parallel to the end face of the stator seat and is fixedly connected to the stator seat through the screw; the elastic mechanism is arranged between the annular gasket and the end face of the stator seat, and is in contact with the annular gasket and the end face of the stator seat at the same time;

[0009] The traveling wave ultrasonic motor housing is fixedly connected to the supporting fixing mechanism; the spiral feed of the spiral micrometer head drives the pre-pressing platform to move, thereby driving the annular gasket, causing the elastic mechanism to deform, and applying pre-pressure to the stator through the stator seat;

[0010] The number of the elastic mechanisms is ≥1; each elastic mechanism is a disc spring, a flexible hinge, or a combination of a disc spring and a flexible hinge.

[0011] Further, the elastic mechanism is a combination of a disc spring and a flexible hinge;

[0012] The disc spring is a hollow flat-bottomed conical structure, and the bottom surface is provided with four through holes spaced 90 degrees apart for positioning the disc spring so that the center of the disc spring is in line with the center of the motor drive shaft.

[0013] The flexible hinge is a hollow drum-shaped structure with annular rigid connectors at both ends, and one end of the annular rigid connector is provided with four threaded holes spaced 90 degrees apart, and screws are used to connect the disc spring and the flexible hinge; the middle raised area of ​​the drum-shaped structure is made of Kovar alloy to prevent the flexible hinge from interfering with the rotation of the motor shaft due to compression and deformation.

[0014] Further, the supporting and fixing mechanism includes a base, a first supporting frame, a second supporting frame, and a third supporting frame;

[0015] The first support frame, the second support frame, and the third support frame are fixedly mounted on the base, and the second support frame can move along the axial direction of the screw micrometer head;

[0016] The traveling wave ultrasonic motor housing is fixedly connected to the first support frame; the flexible pre-pressing head assembly is fixedly connected to the second support frame; the fixed part of the spiral micrometer head is fixedly connected to the third support frame; the spiral feed of the spiral micrometer head pushes the pre-pressing platform, thereby pushing the second support frame to move axially along the spiral micrometer head, causing the elastic mechanism in the flexible pre-pressing head assembly to deform.

[0017] Furthermore, a slider is provided at the bottom of the second support frame, and a guide rail corresponding to the slider is provided on the base, and the slider cooperates with the guide rail to realize the axial movement of the second support frame along the screw micrometer head.

[0018] Furthermore, corresponding mounting holes are respectively provided on the stator seat, annular gasket and second support frame in the flexible pre-pressing head assembly, and the screw rod cooperates with the mounting holes provided on the stator seat, annular gasket and second support frame in turn to realize a fixed connection between the flexible pre-pressing head assembly and the second support frame.

[0019] Furthermore, the mounting hole on the annular gasket is a threaded hole, and the mounting hole on the stator seat is a through hole; the screw rod is a stepped structure with a threaded area and a polished rod area at both ends, and the threaded area and the polished rod area respectively cooperate with the threaded hole on the annular gasket and the through hole on the stator seat.

[0020] Furthermore, a cavity for accommodating the output shaft of the traveling wave ultrasonic motor is provided at one end of the pre-pressing platform, and the inner wall of the cavity does not contact the output shaft of the traveling wave ultrasonic motor, and a blind hole is provided at the other end, and the pre-pressing platform is installed on the screw micrometer through the blind hole, and the blind hole and the screw micrometer are gap-matched.

[0021] Furthermore, the pre-pressure applying device also includes a pressure monitoring mechanism;

[0022] The pressure monitoring mechanism is used to obtain in real time the pre-pressure applied to the stator by the spiral micrometer through the pre-pressure platform, the flexible pre-pressure head assembly and the stator seat in sequence; the pressure monitoring mechanism adjusts the spiral feed of the spiral micrometer according to the pre-pressure to optimize the output performance of the traveling wave ultrasonic motor; the pressure monitoring mechanism obtains the wear law of the friction material provided at the contact point between the stator and the rotor according to the real-time change of the pre-pressure.

[0023] Furthermore, the pressure monitoring mechanism includes an annular film pressure sensor, a pressure display module and a processing control module; the annular film pressure sensor is used to obtain the pressure signal between the pre-pressing platform and the flexible pre-pressing head assembly and output it to the processing control module; the processing control module obtains the pre-pressure according to the pressure signal and outputs it to the pressure display module, adjusts the spiral feed of the screw micrometer according to the pre-pressure, or further processes the pre-pressure to obtain the wear law of the friction material used at the contact point between the stator and the rotor.

[0024] Furthermore, the annular film pressure sensor is arranged between the pre-pressing platform and the second support frame, and is a resistive annular film pressure sensor.

[0025] A method for applying pre-pressure applied to a traveling wave ultrasonic motor performance test is implemented by using the above-mentioned pre-pressure applying device applied to a traveling wave ultrasonic motor performance test, and comprises the following steps:

[0026] The S1 screw micrometer applies preload to the stator through the preload table, the flexible preload head assembly and the stator seat;

[0027] The S2 annular film pressure sensor obtains the pressure signal between the pre-pressing platform and the flexible pre-pressing head assembly and outputs it to the data processing and control module;

[0028] The S3 processing control module obtains the pre-pressure according to the pressure signal and outputs it to the pressure display module, and adjusts the screw feed of the screw micrometer according to the pre-pressure;

[0029] Alternatively, the processing control module further processes the pre-pressure to obtain the wear pattern of the friction material used at the contact point between the stator and the rotor.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) The present invention provides a pre-pressure applying device for a traveling wave ultrasonic motor performance test, which adopts an open pre-pressure applying method, does not require disassembly or modification of the motor interior, and can apply the required pre-pressure in real time, dynamically, and continuously during the traveling wave ultrasonic motor performance test;

[0032] (2) The present invention is a preload applying device for traveling wave ultrasonic motor performance testing, which designs a specific structure of a flexible preload head, and in particular uses a combination of a disc spring and a flexible hinge to achieve the application of flexible preload and uniform distribution of preload;

[0033] (3) The present invention is a pre-stressing device for testing the performance of a traveling wave ultrasonic motor. The specific structure of the supporting and fixing mechanism is designed so that the supporting and fixing mechanism can form a stable support for the traveling wave ultrasonic motor, the flexible pre-stressing head assembly, the pre-stressing platform and the screw micrometer head, and can ensure that each component moves stably or deforms stably during the pre-stressing process, and ensure that the applied pre-stress is uniform and stable and that the pre-stress is easy to maintain;

[0034] (4) The present invention provides a pre-pressure application device and method for testing the performance of a traveling wave ultrasonic motor, which introduces a pressure monitoring mechanism to adjust the screw feed of the screw micrometer according to the pre-pressure, so as to optimize the output performance of the traveling wave ultrasonic motor. The pre-pressure has a wide adjustment range, which can reach 50 to 500N.

[0035] (5) The present invention provides a pre-pressure application device and method for testing the performance of a traveling wave ultrasonic motor, which introduces a pressure monitoring mechanism to obtain the wear law of the friction material provided at the contact point between the stator and the rotor according to the real-time change of the pre-pressure;

[0036] (6) The present invention provides a pre-pressure applying device for traveling wave ultrasonic motor performance testing, which has the advantages of simple structure, convenient adjustment, precision and reliability, and low cost. The pre-pressure applying method implemented by the device can optimize the output performance of the traveling wave ultrasonic motor through real-time adjustment. The operation is simple, labor costs are saved, and technical support is provided for ultrasonic motor performance testing devices. The device and method described in the present invention have broad application prospects in the field of ultrasonic motor testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the assembly of the pre-pressure applying device of the present invention applied to the performance test of the traveling wave ultrasonic motor;

[0038] Figure 2 It is a schematic diagram of the base structure of the present invention;

[0039] Figure 3 is a schematic diagram of a flexible pre-pressing head assembly of the present invention;

[0040] Figure 4 It is a schematic diagram of the disc spring structure of the present invention;

[0041] Figure 5 It is a schematic diagram of the flexible hinge structure of the present invention;

[0042] Figure 6 This is a schematic diagram of the cross-sectional structure of the pre-pressing table of the present invention;

[0043] Figure 7 Schematic diagram of the structure of the resistive annular film pressure sensor and the pressure display module of the present invention. DETAILED DESCRIPTION

[0044] The following detailed description of the present invention will make the features and advantages of the present invention more clear and explicit.

[0045] The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise noted.

[0046] Figure 1-7In the figure, the reference numerals include: 1-base, 2-first support frame, 3-rotor, 4-friction material, 5-stator, 6-disc spring, 7-flexible hinge, 8-stator seat, 9-screw, 10-annular gasket, 11-second support frame, 12-pressure display module, 13-resistive annular film pressure sensor, 14-pre-pressing platform, 15-slider, 16-guide rail, 17-nut, 18-third support frame, 19-screw micrometer.

[0047] like Figure 1 As shown, a device and method for accurately applying pre-pressure applied to a traveling wave ultrasonic motor performance test includes a base 1, a first support frame 2, a flexible hinge 7, a screw 9, an annular gasket 10, a second support frame 11, a pressure display module 12, a resistive annular film pressure sensor 13, a data processing and control module, a pre-pressure platform 14, a slider 15, a guide rail 16, a nut 17, a third support frame 18, and a screw micrometer 19.

[0048] like Figure 2 As shown, the base 1 is provided with threaded through holes for fixing and installing the first support frame 2, the second support frame 11, the third support frame 18 and the guide rail 16. The first support frame 2 is used to fix the traveling wave ultrasonic motor, which is fixed to the first support frame 2 by bolts, and the stator 5 and the stator seat 8 inside the motor are fixed by bolts; the third support frame 18 is used to fix the screw micrometer 19 to ensure that the applied pre-pressure is evenly distributed, and the first support frame 2, the second support frame 11 and the third support frame 18 need to have a high flatness, and there is a high degree of parallelism between the three.

[0049] like Figure 3 As shown, the screw 9 is a stepped type, passing through the second support frame 11, the annular gasket 10, and the stator seat 8 in sequence, connecting the second support frame 11, the annular gasket 10, and the stator seat 8, and constraining the circumferential rotation and radial movement freedom of the stator. The second support frame 11 is fixed on the slider 15, and the slider 15 cooperates with the guide rail 16, so that the second support frame 11 moves back and forth on the guide rail through the slider. The screw micrometer 19 is fixed on the third support frame 18 through the nut 17, and cooperates with the blind hole clearance at one end of the pre-pressing platform 14. The other end of the pre-pressing platform 14 is close to the resistive annular film pressure sensor 13 in contact with the second support frame 11. Through the spiral feeding of the screw micrometer 19, the disc spring 6 and the flexible hinge 7 between the stator seat 8 and the annular gasket 10 are compressed and deformed by force. The applied pressure value can be read through the pressure display module 12 and the data processing and control module, and then the traveling wave ultrasonic motor is applied with precise and controllable pre-pressure.

[0050] Furthermore, a disc spring 6 and a flexible hinge 7 are provided between the stator seat 8 and the annular gasket 10 in sequence. Figure 4 , Figure 5As shown, the disc spring 6 is a flat-bottomed conical structure, and the bottom plane is provided with four through holes spaced 90° apart for positioning the disc spring 6. The flexible hinge 7 is a hollow drum-shaped structure, with annular rigid connectors at both ends, and a circular plane at one end is provided with four threaded holes spaced 90° apart. The disc spring 6 is fixed to the flexible hinge with screws to achieve the connection between the disc spring 6 and the flexible hinge 7; the other end is restrained by the annular gasket 10; the material of the middle flexible drum-shaped raised area is Kovar alloy to prevent the flexible hinge 7 from interfering with the rotation of the motor shaft due to compression deformation. The combination of the two ensures the application of flexible preload and the uniform distribution of preload.

[0051] Furthermore, the annular gasket 10 is provided with a threaded hole, and the stator seat 8 is provided with a through hole, which respectively cooperates with the threaded area and the polished rod area of ​​the stepped long screw 9 to ensure that the circumferential rotation and radial movement freedom of the stator 5 are constrained while the axial movement freedom is retained.

[0052] Further, such as Figure 6 As shown, the left end of the pre-pressing platform 14 is a hollow cylinder, which is in uniform contact with the resistive annular film pressure sensor 13, and the right end is provided with a blind hole to be gap-matched with the screw micrometer head 19.

[0053] Further, such as Figure 7 As shown, the resistive annular film pressure sensor 13 is externally connected to the pressure display module 12 , and its size should not interfere with the uniform application of the pre-pressure and the rotation of the shaft of the traveling wave ultrasonic motor. The pre-pressure value can be accurately read by the pressure display module 12 .

[0054] A method for using a device and method for accurately applying preload pressure for a traveling wave ultrasonic motor performance test includes:

[0055] (1) By twisting the micrometer screw 19 to compress the disc spring 6 and the flexible hinge 7, a flexible pre-pressure is applied to the stator 5, and the resistance value of the resistive annular film pressure sensor 13 changes under pressure, and the pressure can be accurately read by the pressure display module 12. Since the pre-pressure has an important influence on the operating characteristics of the traveling wave ultrasonic motor, the pre-pressure value can be changed by adjusting the micrometer screw 19 multiple times to find the optimal value to optimize the output performance of the traveling wave ultrasonic motor.

[0056] (2) By twisting the micrometer screw 19 to compress the disc spring 6 and the flexible hinge 7, a flexible pre-pressure is applied to the stator 5. At the same time, the pressure resistance of the resistive annular film pressure sensor 13 will change, and the pressure can be accurately read by the pressure display module 12. When the traveling wave ultrasonic motor is running with an appropriate pre-pressure, the friction material 4 on the contact surface of the stator 5 and the rotor 3 will inevitably wear and cause the pre-pressure to change. Therefore, the device can be used to dynamically monitor the change of the pre-pressure with the wear of the friction material 4 in real time, and can further realize the life prediction and life compensation of the motor.

[0057] The present invention has been described in detail above in conjunction with specific implementations and exemplary examples, but these descriptions cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, a variety of equivalent substitutions, modifications or improvements may be made to the technical solution of the present invention and its implementation methods, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be subject to the attached claims.

[0058] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A pre-stress applying device for testing the performance of a traveling wave ultrasonic motor, the traveling wave ultrasonic motor comprising a rotor (3), a stator (5) and a stator seat (8) for fixing the stator, the contact portion between the stator (5) and the rotor (3) being coated with a friction material, characterized in that: The pre-pressure applying device comprises a flexible pre-pressure head assembly, a supporting and fixing mechanism, a pre-pressure platform (14), and a screw micrometer head (19); The supporting and fixing mechanism is used to support the traveling wave ultrasonic motor, the flexible pre-pressing head assembly, the pre-pressing platform (14) and the screw micrometer (19) arranged in sequence, so that the output shaft of the traveling wave ultrasonic motor, the flexible pre-pressing head assembly, the pre-pressing platform (14) and the screw micrometer (19) are coaxial; The flexible pre-pressing head assembly comprises an annular gasket (10), a screw (9) and an elastic mechanism; the pre-pressing platform (14) is sleeved on the screw micrometer (19); the annular gasket (10) is parallel to the end surface of the stator seat (8) and is fixedly connected to the stator seat (8) through the screw (9); the elastic mechanism is arranged between the annular gasket (10) and the end surface of the stator seat (8), and is in contact with the end surface of the annular gasket (10) and the stator seat (8); The traveling wave ultrasonic motor housing is fixedly connected to the supporting fixing mechanism; the spiral feed of the spiral micrometer head (19) drives the pre-pressing platform (14) to move, thereby driving the annular gasket (10), causing the elastic mechanism to deform, and applying pre-pressure to the stator through the stator seat (8); The number of the elastic mechanisms is ≥1; each elastic mechanism is a disc spring, a flexible hinge, or a combination of a disc spring and a flexible hinge; The elastic mechanism is a combination of a disc spring (6) and a flexible hinge (7); The disc spring (6) is a hollow flat-bottomed conical structure, and the bottom surface is provided with four through holes spaced 90 degrees apart for positioning the disc spring (6) so that the center of the disc spring (6) is in line with the center of the motor drive shaft; The flexible hinge (7) is a hollow drum-shaped structure, with annular rigid connectors at both ends, and one end of the annular rigid connector is provided with four threaded holes spaced 90 degrees apart, and screws are used to connect the disc spring (6) and the flexible hinge (7); the middle raised area of ​​the drum-shaped structure is made of Kovar alloy to prevent the flexible hinge (7) from interfering with the rotation of the motor shaft due to compression deformation; The supporting and fixing mechanism comprises a base (1), a first supporting frame (2), a second supporting frame (11), and a third supporting frame (18); The first support frame (2), the second support frame (11), and the third support frame (18) are fixedly mounted on the base (1), and the second support frame (11) can move axially along the screw micrometer (19); The traveling wave ultrasonic motor housing is fixedly connected to the first support frame (2); the flexible pre-pressing head assembly is fixedly connected to the second support frame (11); the fixed part of the screw micrometer (19) is fixedly connected to the third support frame (18); the screw feed of the screw micrometer (19) pushes the pre-pressing platform (14), thereby pushing the second support frame (11) to move axially along the screw micrometer (19), so that the elastic mechanism in the flexible pre-pressing head assembly is deformed; The pre-pressure applying device also includes a pressure monitoring mechanism; The pressure monitoring mechanism is used to obtain in real time the pre-pressure applied to the stator by the screw micrometer (19) through the pre-pressure platform (14), the flexible pre-pressure head assembly and the stator seat (8) in sequence; the pressure monitoring mechanism adjusts the screw feed of the screw micrometer (19) according to the pre-pressure, so that the output performance of the traveling wave ultrasonic motor is optimized; the pressure monitoring mechanism obtains the wear law of the friction material provided at the contact point between the stator (5) and the rotor (3) according to the real-time change of the pre-pressure; The pressure monitoring mechanism comprises an annular film pressure sensor (13), a pressure display module (12) and a processing control module; the annular film pressure sensor (13) is used to obtain a pressure signal between a pre-pressing platform (14) and a flexible pre-pressing head assembly and output it to the processing control module; the processing control module obtains a pre-pressure according to the pressure signal and outputs it to the pressure display module (12), adjusts the screw feed of the screw micrometer (19) according to the pre-pressure, or further processes the pre-pressure to obtain a wear law of the friction material used at the contact point between the stator (5) and the rotor (3); The pre-pressure applying device is used to implement the following pre-pressure applying method: The S1 screw micrometer (19) applies pre-pressure to the stator through the pre-pressure platform (14), the flexible pre-pressure head assembly and the stator seat (8); The S2 annular film pressure sensor (13) obtains the pressure signal between the pre-pressing platform (14) and the flexible pre-pressing head assembly and outputs it to the data processing and control module; The S3 processing control module obtains the pre-pressure according to the pressure signal and outputs it to the pressure display module (12), and adjusts the screw feed of the screw micrometer (19) according to the pre-pressure; Alternatively, the processing control module further processes the pre-pressure to obtain the wear law of the friction material used at the contact point between the stator (5) and the rotor (3).

2. The pre-stress applying device for traveling wave ultrasonic motor performance test according to claim 1, characterized in that: A slider (15) is provided at the bottom of the second support frame (11), and a guide rail (16) corresponding to the slider (15) is provided on the base (1), and the slider (15) cooperates with the guide rail (16) to realize the axial movement of the second support frame (11) along the screw micrometer (19).

3. The pre-stress applying device for traveling wave ultrasonic motor performance test according to claim 1, characterized in that: The stator seat (8), the annular gasket (10) and the second support frame (11) in the flexible pre-pressing head assembly are respectively provided with corresponding mounting holes, and the screw rod (9) is matched with the mounting holes provided on the stator seat (8), the annular gasket (10) and the second support frame (11) in sequence to realize the fixed connection between the flexible pre-pressing head assembly and the second support frame (11).

4. The pre-stress applying device for traveling wave ultrasonic motor performance test according to claim 3, characterized in that: The mounting hole provided on the annular gasket (10) is a threaded hole, and the mounting hole provided on the stator seat (8) is a through hole; the screw rod (9) is a stepped structure with a threaded area and a smooth rod area respectively provided at both ends, and the threaded area and the smooth rod area respectively cooperate with the threaded hole provided on the annular gasket (10) and the through hole provided on the stator seat (8).

5. The pre-stress applying device for the performance test of the traveling wave ultrasonic motor according to claim 3, characterized in that: A cavity for accommodating the output shaft of the traveling wave ultrasonic motor is provided at one end of the pre-pressing platform (14), and the inner wall of the cavity does not contact the output shaft of the traveling wave ultrasonic motor. A blind hole is provided at the other end, and the pre-pressing platform is mounted on the screw micrometer (19) through the blind hole. The blind hole and the screw micrometer (19) are clearance-matched.

6. The pre-stress applying device for traveling wave ultrasonic motor performance test according to claim 1, characterized in that: The annular film pressure sensor (13) is arranged between the pre-pressing platform (14) and the second support frame (11) and is a resistive annular film pressure sensor.

7. A method for applying preload pressure for performance testing of a traveling wave ultrasonic motor, characterized in that: The pre-stress applying device for the performance test of the traveling wave ultrasonic motor according to claim 1 is implemented, comprising the following steps: The S1 screw micrometer (19) applies pre-pressure to the stator through the pre-pressure platform (14), the flexible pre-pressure head assembly and the stator seat (8); The S2 annular film pressure sensor (13) obtains the pressure signal between the pre-pressing platform (14) and the flexible pre-pressing head assembly and outputs it to the data processing and control module; The S3 processing control module obtains the pre-pressure according to the pressure signal and outputs it to the pressure display module (12), and adjusts the screw feed of the screw micrometer (19) according to the pre-pressure; Alternatively, the processing control module further processes the pre-pressure to obtain the wear law of the friction material used at the contact point between the stator (5) and the rotor (3).

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