Multi-stator traveling wave driven hollow rotary ultrasonic motor and method thereof

Abstract

The invention discloses a multi-stator traveling wave driven hollow rotary ultrasonic motor and a method thereof. The hollow rotary ultrasonic motor comprises a base, a shell, a fixed ring, a stator module, a rotor and a rolling bearing, the stator module comprises a stator bracket and N stator units; the stator unit comprises first to second adjusting bolts, first to second adjusting springs, first to fourth fixing bolts, first to fourth fixing nuts, a stator seat, a metal substrate, first to fourth piezoelectric ceramic pieces, and first to fourth driving feet. During working, the stator units are excited by two-phase signals, so that the driving feet on the stator units generate elliptical motion to drive the rotor to rotate, and the effect of simulating traveling wave driving is achieved by controlling the phases of the signals received by the stator units. According to the invention, a multi-stator traveling wave driving mode is adopted, modular design is adopted, the stator is convenient to disassemble and replace, and the motor has the advantages of large size, large hollow space and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of motors, and in particular relates to a hollow type rotating ultrasonic motor driven by multiple stators and a traveling wave and a method thereof. Background Art

[0002] Space laser communication uses laser as the communication medium, and has unique advantages such as large communication bandwidth, high communication rate, and long transmission distance. However, due to the narrow laser beam, it is difficult to detect and capture the signal and maintain a good communication link. This requires real-time tracking, aiming, and capturing of the laser beam. The traveling wave type hollow rotary ultrasonic motor has the advantages of low speed, large torque, excellent electromagnetic compatibility, passive self-locking, fast response, and vacuum resistance, and is widely used in space laser communication. However, the traveling wave type hollow rotary ultrasonic motor also has disadvantages such as: the need for higher-order traveling waves at large sizes, low energy utilization, and high overall maintenance and replacement costs, which makes it difficult to meet the needs of laser tracking and aiming systems at large sizes. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a hollow rotary ultrasonic motor driven by a multi-stator type traveling wave and a method thereof in view of the defects involved in the background technology.

[0004] The present invention adopts the following technical solutions to solve the above technical problems:

[0005] A hollow rotary ultrasonic motor driven by multiple stators and traveling waves, comprising a base, a housing, a fixing ring, a stator module, a rotor and a rolling bearing;

[0006] The base is in the shape of a disk, and a through hole for output is provided in the center;

[0007] The shell is a hollow cylinder with an opening at the lower end, and a through hole for output is provided at the center of the upper end surface;

[0008] The fixing ring is in the shape of a ring, is arranged in the housing, and is coaxially fixedly connected to the base;

[0009] The rotor is a hollow cylinder with openings at both ends;

[0010] The rolling bearing is arranged in the fixing ring, and the outer ring thereof is coaxially fixedly connected to the inner wall of the fixing ring, and the outer ring is coaxially fixedly connected to the outer wall of the rotor;

[0011] The stator module includes a stator bracket and N stator units, where N is a natural number greater than or equal to 2;

[0012] The stator bracket is a hollow cylinder with openings at both ends, and its outer wall is evenly provided with N blind mounting grooves corresponding to the stator units in a one-to-one manner in the circumferential direction; a rectangular through hole is provided in the center of the blind mounting groove, and the first and second threaded through holes are symmetrically provided on both sides of the rectangular through hole of the blind mounting groove;

[0013] The lower end of the stator bracket is coaxially fixedly connected to the fixing ring and is sleeved outside the rotor;

[0014] The N stator units have the same structure, and all include first to second adjusting bolts, first to second adjusting springs, first to fourth fixing bolts, first to fourth fixing nuts, a stator seat, a metal matrix, first to fourth piezoelectric ceramic sheets, and first to fourth driving feet;

[0015] The metal substrate is a rectangular plate, using B 03 Mode and B 30 Mode as its working mode, B 03 The three nodal lines of the mode and B 30 The three nodal lines of the mode form a four-square grid, and the four-square grid is sequentially divided into the first to fourth square grids in a clockwise direction; the metal substrate is provided with first to fourth fixing through holes corresponding to the first to fourth fixing bolts at the midpoints of the four sides of the four-square grid;

[0016] The first to fourth piezoelectric ceramic sheets are all square piezoelectric ceramic sheets, which are arranged one by one at the centers of the first to fourth grids on the back of the metal substrate, and are polarized along the thickness direction. The first and second piezoelectric ceramic sheets have the same polarization direction, the third and fourth piezoelectric ceramic sheets have the same polarization direction, and the first and third piezoelectric ceramic sheets have opposite polarization directions.

[0017] The first to fourth driving feet are arranged one by one in the first to fourth grids on the front of the metal substrate, and the connecting line between the first driving foot and the second driving foot, and the connecting line between the third driving foot and the second driving foot are parallel to the upper side length of the metal substrate; the first and second driving feet are located between the third and fourth driving feet, and the first and third driving feet are located at B 03 The midpoint of the modal node line and the trough, the second and fourth driving feet are located at B 03 The midpoint position of the modal node line and wave crest;

[0018] The stator seat comprises a fixing portion, a first clamping portion and a second clamping portion;

[0019] The fixing portion is a rectangular parallelepiped, comprising a first end face, a second end face, and first to fourth side walls connected end to end in sequence, wherein the first end face is provided with first to fourth positioning columns corresponding one to one with the first to fourth fixing through holes, and the second end face is provided with first to fourth countersunk through holes corresponding one to one with the first to fourth fixing bolts along the axis of the first to fourth positioning columns;

[0020] The first to fourth positioning columns have the same structure, and their length is greater than the thickness of the first piezoelectric ceramic sheet; the first to fourth fixing bolts pass through the corresponding countersunk through holes on the second end surface of the fixing portion and are threadedly connected with the first to fourth fixing nuts one by one, thereby fixing the metal substrate on the first to fourth positioning columns;

[0021] The first clamping part and the second clamping part have the same structure, and are both provided with a fixed blind hole, and the fixed blind hole is provided with a smooth through hole coaxial with the fixed blind hole;

[0022] The first clamping part and the second clamping part are symmetrically arranged on the second and fourth side walls of the fixing part; the first adjusting bolt passes through the smooth through hole in the fixing blind hole of the first clamping part and is threadedly connected with the first threaded through hole of the mounting blind groove corresponding to the stator unit in which it is located; the first adjusting spring sleeve is outside the stud of the first adjusting bolt and is arranged in the fixing blind hole of the first clamping part, one end of which is abutted against the first adjusting bolt, and the other end is abutted against the first clamping part; the second adjusting bolt passes through the smooth through hole in the fixing blind hole of the second clamping part and is threadedly connected with the second threaded through hole of the mounting blind groove corresponding to the stator unit in which it is located; the second adjusting spring sleeve is outside the stud of the second adjusting bolt and is arranged in the fixing blind hole of the second clamping part, one end of which is abutted against the second adjusting bolt, and the other end is abutted against the second clamping part; so that the metal base extends from the rectangular through hole in the center of the mounting blind groove corresponding to the stator unit in which it is located, the first to fourth driving feet are all abutted against the outer wall of the rotor, and the third driving foot is located between the first driving foot and the fixing ring;

[0023] The first and second driving feet of the N stator units are coplanar and the plane is perpendicular to the axis of the rotor.

[0024] As a further optimization scheme of the hollow type rotary ultrasonic motor with multiple stators and traveling wave drive of the present invention, it also includes a first clamp ring and a second clamp ring;

[0025] The first clamping ring and the second clamping ring have the same structure, and their inner walls are both provided with internal threads;

[0026] The outer wall of the rotor is provided with an external thread matching the internal threads of the first clamping ring and the second clamping ring;

[0027] The rotor and the inner ring of the rolling bearing are transitionally matched;

[0028] The first clamping ring and the second clamping ring are respectively arranged on both sides of the inner ring of the rolling bearing and are both connected to the rotor thread to lock the rotor on the inner ring of the rolling bearing.

[0029] As a further optimization scheme for a hollow rotary ultrasonic motor with a multi-stator traveling wave drive according to the present invention, the first to fourth positioning columns are provided with chamfers at one end away from the second end face of the stator seat fixing part, and the first to fourth fixing through holes on the back side of the metal substrate are also provided with chamfers to facilitate positioning.

[0030] As a further optimization scheme of the hollow rotary ultrasonic motor with multiple stators and traveling wave drive of the present invention, the first to fourth piezoelectric ceramic sheets are adhered to the metal substrate by epoxy resin glue.

[0031] The present invention also discloses a working method of the multi-stator traveling wave driven hollow type rotary ultrasonic motor, comprising the following steps:

[0032] Arrange the N stator units one by one in a clockwise direction;

[0033] If it is necessary to drive the rotor to rotate forward and generate class B 0n The traveling wave driving mode applies a signal to the first and second piezoelectric ceramic plates of the i-th stator unit. Apply a signal to the third and fourth piezoelectric ceramic plates of the i-th stator unit i is a natural number greater than or equal to 1 and less than or equal to N, U is the preset voltage amplitude, ω is the preset voltage frequency, is the preset initial phase, n is the type B 0n The traveling order of the traveling wave;

[0034] If it is necessary to drive the rotor to rotate in the opposite direction and produce Class B 0n The traveling wave driving mode applies a signal to the first and second piezoelectric ceramic plates of the i-th stator unit. Apply a signal to the third and fourth piezoelectric ceramic plates of the i-th stator unit

[0035] Compared with the prior art, the present invention adopts the above technical solution and has the following technical effects:

[0036] The present invention adopts a multi-stator structural design, which enables it to operate in low-order modes at any size. This not only breaks through the size constraints of ultrasonic motors, but also improves the utilization rate of vibration energy of the whole machine. At the same time, the discrete multi-stator structure also brings about an improvement in the stator replaceability of the motor, reducing the cost of maintenance of the whole machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the structure of the present invention;

[0038] Figure 2 It is a structural schematic diagram of the stator module in the present invention;

[0039] Figure 3 It is a structural schematic diagram of the stator bracket in the present invention;

[0040] Figure 4 is a cross-sectional schematic diagram of a stator unit in the present invention;

[0041] Figure 5 It is a schematic diagram of the structure of the first to fourth driving feet and the metal base in the present invention;

[0042] Figure 6 The first to fourth driving feet, the first to fourth piezoelectric ceramic sheets and the metal substrate in the present invention are 03 Mode and B 30 Schematic diagram of the position relationship of the node line under the mode;

[0043] Figure 7 The metal matrix of the present invention is 03 Mode, B 30 Schematic diagram of the comparison of the positions of the first to fourth driving feet during the modal state;

[0044] Figure 8 The present invention drives the rotor to rotate in the positive direction and produces class B 0n Schematic diagram of driving signal when the traveling wave driving mode is used;

[0045] Fig. 9 The present invention drives the rotor to rotate in the opposite direction and produces a type B 0n Schematic diagram of driving signal when the traveling wave driving mode is used;

[0046] In the figure, 1-base, 2-shell, 3-fixing ring, 4-stator module, 5-rotor, 6-rolling bearing, 7-first clamping ring, 8-second clamping ring, 9-stator bracket, 10-stator unit, 11-metal matrix, 12-first driving foot, 13-second piezoelectric ceramic plate, 14-fixing part of stator seat, 15-first clamping part of stator seat, 16-second clamping part of stator seat, 17-first adjusting bolt, 18-first adjusting spring, 19-first fixing bolt, 20-first positioning column, 21-first fixing nut, 22-second driving foot, 23-third driving foot, 24-fourth driving foot,. DETAILED DESCRIPTION

[0047] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings:

[0048] The present invention can be implemented in many different forms and should not be considered to be limited to the embodiments described herein. On the contrary, these embodiments are provided to make this disclosure thorough and complete, and will fully express the scope of the present invention to those skilled in the art. In the accompanying drawings, components are enlarged for clarity.

[0049] like Figure 1 As shown, the present invention discloses a multi-stator traveling wave driven hollow type rotary ultrasonic motor, comprising a base, a housing, a fixing ring, a stator module, a rotor and a rolling bearing;

[0050] The base is in the shape of a disk, and a through hole for output is provided in the center;

[0051] The shell is a hollow cylinder with an opening at the lower end, and a through hole for output is provided at the center of the upper end surface;

[0052] The fixing ring is in the shape of a ring, is arranged in the housing, and is coaxially fixedly connected to the base;

[0053] The rotor is a hollow cylinder with openings at both ends;

[0054] The rolling bearing is arranged in the fixing ring, and the outer ring thereof is coaxially fixedly connected to the inner wall of the fixing ring, and the outer ring is coaxially fixedly connected to the outer wall of the rotor;

[0055] like Figure 2 As shown, the stator module includes a stator bracket and N stator units, where N is a natural number greater than or equal to 2;

[0056] like Figure 3 As shown, the stator bracket is a hollow cylinder with openings at both ends, and its outer wall is evenly provided with N blind mounting grooves corresponding to the stator units in a one-to-one manner in the circumferential direction; a rectangular through hole is provided in the center of the blind mounting groove, and the first and second threaded through holes are symmetrically provided on both sides of the rectangular through hole of the blind mounting groove;

[0057] The lower end of the stator bracket is coaxially fixedly connected to the fixing ring and is sleeved outside the rotor;

[0058] The N stator units have the same structure, and all include first to second adjusting bolts, first to second adjusting springs, first to fourth fixing bolts, first to fourth fixing nuts, a stator seat, a metal matrix, first to fourth piezoelectric ceramic sheets, and first to fourth driving feet. Figure 4 As shown;

[0059] The metal substrate is a rectangular plate, using B 03 Mode and B 30 Mode as its working mode, B 03 The three nodal lines of the mode and B 30 The three nodal lines of the mode form a four-square grid, and the four-square grid is sequentially divided into the first to fourth square grids in a clockwise direction; the metal substrate is provided with first to fourth fixing through holes corresponding to the first to fourth fixing bolts at the midpoints of the four sides of the four-square grid;

[0060] The first to fourth piezoelectric ceramic sheets are all square piezoelectric ceramic sheets, which are arranged one by one in the center of the first to fourth grids on the back of the metal substrate. Figure 6 As shown, they are all polarized along the thickness direction, the polarization directions of the first and second piezoelectric ceramic sheets are the same, the polarization directions of the third and fourth piezoelectric ceramic sheets are the same, and the polarization directions of the first and third piezoelectric ceramic sheets are opposite;

[0061] like Figure 5 , Figure 6 As shown, the first to fourth driving feet are arranged one by one in the first to fourth grids on the front of the metal substrate, and the connecting line between the first driving foot and the second driving foot and the connecting line between the third driving foot and the second driving foot are parallel to the upper side length of the metal substrate; the first and second driving feet are located between the third and fourth driving feet, and the first and third driving feet are located at B 03 The midpoint of the modal node line and the trough, the second and fourth driving feet are located at B 03 The midpoint position of the modal node line and the wave crest is as follows: Figure 7 As shown;

[0062] The stator seat comprises a fixing portion, a first clamping portion and a second clamping portion;

[0063] The fixing portion is a rectangular parallelepiped, comprising a first end face, a second end face, and first to fourth side walls connected end to end in sequence, wherein the first end face is provided with first to fourth positioning columns corresponding one to one with the first to fourth fixing through holes, and the second end face is provided with first to fourth countersunk through holes corresponding one to one with the first to fourth fixing bolts along the axis of the first to fourth positioning columns;

[0064] The first to fourth positioning columns have the same structure, and their length is greater than the thickness of the first piezoelectric ceramic sheet; the first to fourth fixing bolts pass through the corresponding countersunk through holes on the second end surface of the fixing portion and are threadedly connected with the first to fourth fixing nuts one by one, thereby fixing the metal substrate on the first to fourth positioning columns;

[0065] The first clamping part and the second clamping part have the same structure, and are both provided with a fixed blind hole, and the fixed blind hole is provided with a smooth through hole coaxial with the fixed blind hole;

[0066] The first clamping part and the second clamping part are symmetrically arranged on the second and fourth side walls of the fixing part; the first adjusting bolt passes through the smooth through hole in the fixing blind hole of the first clamping part and is threadedly connected with the first threaded through hole of the mounting blind groove corresponding to the stator unit in which it is located; the first adjusting spring sleeve is outside the stud of the first adjusting bolt and is arranged in the fixing blind hole of the first clamping part, one end of which is abutted against the first adjusting bolt, and the other end is abutted against the first clamping part; the second adjusting bolt passes through the smooth through hole in the fixing blind hole of the second clamping part and is threadedly connected with the second threaded through hole of the mounting blind groove corresponding to the stator unit in which it is located; the second adjusting spring sleeve is outside the stud of the second adjusting bolt and is arranged in the fixing blind hole of the second clamping part, one end of which is abutted against the second adjusting bolt, and the other end is abutted against the second clamping part; so that the metal base extends from the rectangular through hole in the center of the mounting blind groove corresponding to the stator unit in which it is located, the first to fourth driving feet are all abutted against the outer wall of the rotor, and the third driving foot is located between the first driving foot and the fixing ring;

[0067] The first and second driving feet of the N stator units are coplanar and the plane is perpendicular to the axis of the rotor.

[0068] As a further optimization scheme of the hollow type rotary ultrasonic motor with multiple stators and traveling wave drive of the present invention, it also includes a first clamp ring and a second clamp ring;

[0069] The first clamping ring and the second clamping ring have the same structure, and their inner walls are both provided with internal threads;

[0070] The outer wall of the rotor is provided with an external thread matching the internal threads of the first clamping ring and the second clamping ring;

[0071] The rotor and the inner ring of the rolling bearing are transitionally matched;

[0072] The first clamping ring and the second clamping ring are respectively arranged on both sides of the inner ring of the rolling bearing and are both connected to the rotor thread to lock the rotor on the inner ring of the rolling bearing.

[0073] As a further optimization scheme for a hollow rotary ultrasonic motor with a multi-stator traveling wave drive according to the present invention, the first to fourth positioning columns are provided with chamfers at one end away from the second end face of the stator seat fixing part, and the first to fourth fixing through holes on the back side of the metal substrate are also provided with chamfers to facilitate positioning.

[0074] As a further optimization scheme of the hollow rotary ultrasonic motor with multiple stators and traveling wave drive of the present invention, the first to fourth piezoelectric ceramic sheets are adhered to the metal substrate by epoxy resin glue.

[0075] The present invention also discloses a working method of the multi-stator traveling wave driven hollow type rotary ultrasonic motor, comprising the following steps:

[0076] Arrange the N stator units one by one in a clockwise direction;

[0077] like Figure 8 As shown, if it is necessary to drive the rotor to rotate in the positive direction and produce type B 0n Driving mode of traveling wave:

[0078] All stators are numbered in a clockwise direction, i.e., stator No. 1, stator No. 2, ..., stator No. i, ..., stator No. N. The metal substrates of all stators are grounded, and a group of sinusoidal voltage signals are applied to the piezoelectric ceramic sheets of each stator. The group number of the voltage signal corresponds to the stator serial number one by one. Each group of voltage signals includes a first voltage signal and a second voltage signal. The phase difference between the first voltage signal and the second voltage signal is π / 2. The first voltage signal is applied to the first and fourth piezoelectric ceramic sheets of the stator, and the second voltage signal is applied to the second and third piezoelectric ceramic sheets of the stator. All applied signals are voltage signals of the same frequency and the same amplitude. There are N groups of voltage signals in total, which are expressed as follows:

[0079] The first group of voltage signals u1:

[0080]

[0081] The second set of voltage signals u2:

[0082]

[0083]

[0084] …

[0085] The i-th group of voltage signals u i :

[0086]

[0087] …

[0088] The Nth group of voltage signals u N :

[0089]

[0090] U is the preset voltage amplitude, ω is the preset voltage frequency, is the preset initial phase. Each set of signals causes the driving foot on the corresponding stator to produce an elliptical motion, thereby driving the rotor to rotate through friction. 0n Traveling wave, add the corresponding phase Ψ to each group of voltage signals i , phase Ψ i The size depends on the order n of the traveling wave to be analogized and the total number N of stators, and the phase Ψ i The expression is as follows:

[0091]

[0092] The more stators there are, the higher the order of traveling waves that can be simulated, and the simulation of low-order traveling waves is more vivid.

[0093] like Fig. 9 As shown, if it is necessary to drive the rotor to rotate in the opposite direction and produce type B 0n Driving mode of traveling wave:

[0094] All stators are numbered in a clockwise direction, i.e., stator No. 1, stator No. 2, ..., stator No. i, ..., stator No. N. The metal substrates of all stators are grounded, and a group of sinusoidal voltage signals are applied to the piezoelectric ceramic sheets of each stator. The group number of the voltage signal corresponds to the stator serial number one by one. Each group of voltage signals includes a first voltage signal and a second voltage signal. The phase difference between the first voltage signal and the second voltage signal is -π / 2. The first voltage signal is applied to the first and fourth piezoelectric ceramic sheets of the stator, and the second voltage signal is applied to the second and third piezoelectric ceramic sheets of the stator. All applied signals are voltage signals of the same frequency and the same amplitude. There are a total of N groups of voltage signals, which are expressed as follows:

[0095] The first group of voltage signals u1:

[0096]

[0097] The second set of voltage signals u2:

[0098]

[0099]

[0100] …

[0101] The i-th group of voltage signals u i :

[0102]

[0103] …

[0104] The Nth group of voltage signals u N :

[0105]

[0106] Each set of signals causes the corresponding driving foot on the stator to produce an elliptical motion, which in turn drives the rotor to rotate through friction. 0n Traveling wave, add the corresponding phase Ψ to each group of voltage signals i , phase Ψ iThe size depends on the order n of the traveling wave to be analogized and the total number N of stators, and the phase Ψ i The expression is as follows:

[0107]

[0108] The more stators there are, the higher the order of traveling waves that can be simulated, and the simulation of low-order traveling waves is more vivid.

[0109] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.

[0110] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A hollow type rotary ultrasonic motor driven by multiple stators and traveling waves, characterized in that: It includes base, housing, fixing ring, stator module, rotor and rolling bearing; The base is in the shape of a disk, and a through hole for output is provided in the center; The shell is a hollow cylinder with an opening at the lower end, and a through hole for output is provided at the center of the upper end surface; The fixing ring is in the shape of a ring, is arranged in the housing, and is coaxially fixedly connected to the base; The rotor is a hollow cylinder with openings at both ends; The rolling bearing is arranged in the fixing ring, and the outer ring thereof is coaxially fixedly connected to the inner wall of the fixing ring, and the outer ring is coaxially fixedly connected to the outer wall of the rotor; The stator module includes a stator bracket and N stator units, where N is a natural number greater than or equal to 2; The stator bracket is a hollow cylinder with openings at both ends, and its outer wall is evenly provided with N blind mounting grooves corresponding to the stator units in a one-to-one manner in the circumferential direction; a rectangular through hole is provided in the center of the blind mounting groove, and the first and second threaded through holes are symmetrically provided on both sides of the rectangular through hole of the blind mounting groove; The lower end of the stator bracket is coaxially fixedly connected to the fixing ring and is sleeved outside the rotor; The N stator units have the same structure, and all include first to second adjusting bolts, first to second adjusting springs, first to fourth fixing bolts, first to fourth fixing nuts, a stator seat, a metal matrix, first to fourth piezoelectric ceramic sheets, and first to fourth driving feet; The metal substrate is a rectangular plate, using B 03 Mode and B 30 Mode as its working mode, B 03 The three nodal lines of the mode and B 30 The three nodal lines of the mode form a four-square grid, and the four-square grid is sequentially divided into the first to fourth square grids in a clockwise direction; the metal substrate is provided with first to fourth fixing through holes corresponding to the first to fourth fixing bolts at the midpoints of the four sides of the four-square grid; The first to fourth piezoelectric ceramic sheets are all square piezoelectric ceramic sheets, which are arranged one by one at the centers of the first to fourth grids on the back of the metal substrate, and are polarized along the thickness direction. The first and second piezoelectric ceramic sheets have the same polarization direction, the third and fourth piezoelectric ceramic sheets have the same polarization direction, and the first and third piezoelectric ceramic sheets have opposite polarization directions. The first to fourth driving feet are arranged one by one in the first to fourth grids on the front side of the metal substrate, and the connecting line between the first driving foot and the second driving foot and the connecting line between the third driving foot and the second driving foot are parallel to the upper side length of the metal substrate; The first and second driving feet are located between the third and fourth driving feet, and the first and third driving feet are located at B 03 The midpoint of the modal node line and the trough, the second and fourth driving feet are located at B 03 The midpoint position of the modal node line and wave crest; The stator seat comprises a fixing portion, a first clamping portion and a second clamping portion; The fixing portion is a rectangular parallelepiped, comprising a first end face, a second end face, and first to fourth side walls connected end to end in sequence, wherein the first end face is provided with first to fourth positioning columns corresponding one to one with the first to fourth fixing through holes, and the second end face is provided with first to fourth countersunk through holes corresponding one to one with the first to fourth fixing bolts along the axis of the first to fourth positioning columns; The first to fourth positioning columns have the same structure, and their length is greater than the thickness of the first piezoelectric ceramic sheet; the first to fourth fixing bolts pass through the corresponding countersunk through holes on the second end surface of the fixing portion and are threadedly connected with the first to fourth fixing nuts one by one, thereby fixing the metal substrate on the first to fourth positioning columns; The first clamping part and the second clamping part have the same structure, and are both provided with a fixed blind hole, and the fixed blind hole is provided with a smooth through hole coaxial with the fixed blind hole; The first clamping part and the second clamping part are symmetrically arranged on the second and fourth side walls of the fixing part; the first adjusting bolt passes through the smooth through hole in the fixing blind hole of the first clamping part and is threadedly connected with the first threaded through hole of the mounting blind groove corresponding to the stator unit in which it is located; the first adjusting spring sleeve is outside the stud of the first adjusting bolt and is arranged in the fixing blind hole of the first clamping part, one end of which is abutted against the first adjusting bolt, and the other end is abutted against the first clamping part; the second adjusting bolt passes through the smooth through hole in the fixing blind hole of the second clamping part and is threadedly connected with the second threaded through hole of the mounting blind groove corresponding to the stator unit in which it is located; the second adjusting spring sleeve is outside the stud of the second adjusting bolt and is arranged in the fixing blind hole of the second clamping part, one end of which is abutted against the second adjusting bolt, and the other end is abutted against the second clamping part; so that the metal base extends from the rectangular through hole in the center of the mounting blind groove corresponding to the stator unit in which it is located, the first to fourth driving feet are all abutted against the outer wall of the rotor, and the third driving foot is located between the first driving foot and the fixing ring; The first and second driving feet of the N stator units are coplanar and the plane is perpendicular to the axis of the rotor.

2. The hollow type rotary ultrasonic motor with multiple stators and traveling wave drive according to claim 1, characterized in that: Also includes a first clasp and a second clasp; The first clamping ring and the second clamping ring have the same structure, and their inner walls are both provided with internal threads; The outer wall of the rotor is provided with an external thread matching the internal threads of the first clamping ring and the second clamping ring; The rotor and the inner ring of the rolling bearing are transitionally matched; The first clamping ring and the second clamping ring are respectively arranged on both sides of the inner ring of the rolling bearing and are both connected to the rotor thread to lock the rotor on the inner ring of the rolling bearing.

3. The hollow type rotary ultrasonic motor with multiple stators and traveling wave drive according to claim 1, characterized in that: The ends of the first to fourth positioning columns away from the second end surface of the stator seat fixing portion are all chamfered, and the first to fourth fixing through holes on the back side of the metal substrate are also chamfered to facilitate positioning.

4. The hollow type rotary ultrasonic motor with multiple stators and traveling wave drive according to claim 1, characterized in that: The first to fourth piezoelectric ceramic sheets are adhered to the metal substrate by epoxy resin glue.

5. The working method of the hollow type rotary ultrasonic motor with multiple stators and traveling wave drive according to claim 1 is characterized in that: The following steps are involved: Arrange the N stator units one by one in a clockwise direction; If it is necessary to drive the rotor to rotate forward and generate class B 0n The traveling wave driving mode applies a signal to the first and second piezoelectric ceramic plates of the i-th stator unit. Apply a signal to the third and fourth piezoelectric ceramic plates of the i-th stator unit i is a natural number greater than or equal to 1 and less than or equal to N, U is the preset voltage amplitude, ω is the preset voltage frequency, is the preset initial phase, n is the type B 0n The traveling order of the traveling wave; If it is necessary to drive the rotor to rotate in the opposite direction and produce Class B 0n The traveling wave driving mode applies a signal to the first and second piezoelectric ceramic plates of the i-th stator unit. Apply a signal to the third and fourth piezoelectric ceramic plates of the i-th stator unit

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