Standing wave micro motor stator structure, design method, preparation method and micro motor

Abstract

The invention discloses a standing wave micro motor stator structure, a design method, a preparation method and a micro motor, and belongs to the field of micro electro mechanical systems. The standing wave micro motor stator structure comprises a substrate, driving teeth, balancing teeth and a piezoelectric layer; the driving teeth, the balance teeth and the piezoelectric layer are all arranged on the substrate; the driving teeth make contact with the rotor and drive the rotor to rotate through friction force. The balance teeth are used for counteracting mass eccentricity caused by the driving teeth; the piezoelectric layer is used for converting electric energy into mechanical energy and driving the stator structure to vibrate according to a working mode; a locking structure is further manufactured on the base plate and used for locking the shape of the working mode of the stator structure, so that the driving teeth are located on the slope of the vibration shape of the working mode, the driving teeth move obliquely, it is guaranteed that the wave crest of the clockwise working mode and the locking structure are in the same direction, and it is guaranteed that the pitch diameter of the anticlockwise working mode and the locking structure are in the same direction. The complexity of the micro motor driving circuit can be simplified, the power consumption is reduced, and the preparation process cost is reduced.

Description

Technical Field

[0001] The present invention relates to the field of microelectromechanical systems, and more specifically, to a standing wave micromotor stator structure, a design method, a preparation method, and a micro motor. Background Art

[0002] A micromotor or a micro motor mainly realizes the conversion of electrical energy into mechanical energy through working principles such as electromagnetic, piezoelectric, electrostatic, or thermal effects, and has advantages and characteristics such as miniaturization, precise control, and high efficiency, and has broad application prospects in multiple fields. The main applications of micro motors are as follows: micro robots, micro low-power drivers, and micro medical detection devices. Among them, micro robots utilize the characteristics of small size, low operating voltage, and high control accuracy of micro motors, and can be used for mobile platforms, micro mechanical assembly, repair, nano positioning, etc. And in the field of consumer electronics, such as autofocusing, zooming, and anti-shaking of smartphone cameras

[0003] MEMS micro motors have the advantages of small volume, light weight, easy integration with the substrate structure, and displacement generated by the solid crystallization effect of materials, with high displacement resolution, large output force, large load-bearing capacity, fast response speed, and large instantaneous acceleration, and have received wide attention. It is a MEMS actuator technology suitable for the requirements of micro motors to provide high-resolution positioning, high-dynamic motion characteristics, etc.

[0004] Some term explanations related to the technical solution of the present invention are as follows:

[0005] MEMS: Micro-Electro-Mechanical System (MEMS), also called microelectronic mechanical system, microsystem, micromachine, etc., is developed on the basis of microelectronic technology (semiconductor manufacturing technology), and integrates technologies such as lithography, etching, thin film, LIGA, silicon microfabrication, non-silicon microfabrication, and precision machining to produce high-tech electro-mechanical devices.

[0006] Piezoelectric effect: When certain materials are deformed under the action of an external force in a certain direction, polarization phenomena will occur inside them, and at the same time, positive and negative charges with opposite polarities will appear on its two opposite surfaces. When the external force is removed, it will return to the uncharged state again, and this phenomenon is called the positive piezoelectric effect. When the direction of the acting force changes, the polarity of the charge also changes accordingly. On the contrary, when an electric field is applied in the polarization direction of the material, these materials will also deform, and when the electric field is removed, the deformation of the material will disappear, and this phenomenon is called the inverse piezoelectric effect.

[0007] Piezoelectric actuator: A piezoelectric actuator utilizes the piezoelectric effect of piezoelectric materials to achieve an energy conversion function, converts the input electrical signal into mechanical energy output, and is one of the commonly used actuators in the MEMS field.

[0008] Piezoelectric material: A material with piezoelectric effect.

[0009] Mode: The inherent vibration characteristics of any structure. When the structure resonates, the mode refers to the eigenvalues of the resonance frequency and vibration mode of the structure.

[0010] Currently, due to the limited thickness of the driving structure layer of the PZT thin film traveling wave micromotor with conventional design, the output torque of the micromotor is restricted to a certain extent, and it is difficult to integrate other materials additionally in the MEMS process to form the driving teeth; the process of the MEMS traveling wave ultrasonic motor based on silicon-based PZT SOI is relatively complex, and the cost of wafer processing and raw materials is relatively high. Even if it is easy to batch, it is difficult to reduce the cost of a single motor. Moreover, the driving circuit is complex, and the cost, volume, and power consumption are higher. Summary of the Invention

[0011] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a standing wave micromotor stator structure, design method, preparation method, and micromotor, which can simplify the complexity of the micromotor driving circuit, reduce power consumption, and lower the preparation process cost.

[0012] The purpose of the present invention is achieved through the following solutions:

[0013] A standing wave micromotor stator structure includes: a substrate, driving teeth, balancing teeth, and a piezoelectric layer; the driving teeth, balancing teeth, and piezoelectric layer are all arranged on the substrate; the driving teeth are in contact with the rotor, and the driving teeth drive the rotor to rotate through friction; the balancing teeth are used to offset the mass eccentricity caused by the driving teeth; the piezoelectric layer is used to convert electrical energy into mechanical energy and drive the stator structure to vibrate according to the working mode; a locking structure is also made on the substrate to lock the shape of the working mode of the stator structure, so that the driving teeth are located on the slope of the working mode vibration shape, and the driving teeth generate an oblique movement, ensuring that the wave crest of the clockwise working mode has the same direction as the locking structure, and ensuring that the nodal diameter of the counterclockwise working mode has the same direction as the locking structure.

[0014] Further, the substrate includes a metal substrate or a metal alloy substrate.

[0015] Further, in the clockwise working mode, taking any wave crest or wave trough as a reference point, the driving tooth closest to this reference point is located in the clockwise direction of the reference point.

[0016] Further, in the counterclockwise mode, taking any wave crest or wave trough as a reference point, the driving tooth closest to this reference point is located in the counterclockwise direction of the reference point.

[0017] Further, the locking structure includes a notch and / or a column, and the notch or square column closest to each driving tooth is located in the clockwise direction of the driving tooth.

[0018] Further, the driving teeth and the balancing teeth are located on the same side or different sides of the substrate; when the driving teeth and the balancing teeth are located on the same side of the substrate, the balancing teeth are lower than the driving teeth in height.

[0019] Further, the shape of the driving teeth includes any one of a hemisphere, a semi-elliptical sphere, a cylinder, a square column, a cone, and a column with a polygon as the bottom surface.

[0020] Further, the shape of the notch includes any one of a square, a semi-circle, a triangle, and a polygon; the shape of the bottom surface of the column includes any one of a square, a circle, a triangle, and a polygon.

[0021] Further, when the square-column locking working mode is adopted, the square column and the driving teeth are located on the same surface or different surfaces of the substrate; when the driving teeth and the square column are located on the same side of the substrate, the square column can be lower than, higher than, or equal to the driving teeth in height. When the square column is higher than or equal to the driving teeth, the corresponding position of the rotor needs to be cleared.

[0022] Further, an anchor point is provided at the center position of the substrate. Through the rotation axis of the anchor point, the function of providing a rotation constraint axis for the rotation of the rotor can be achieved.

[0023] Further, the metal substrate includes a circular metal substrate; if the number of working modes is n, the number of driving teeth is equal to 2*n; all the driving teeth have the same shape and volume, and all the driving teeth are evenly distributed on a circle with the same center as the center of the metal substrate. The adjacent driving teeth differ by 180 / n degrees in direction; the balancing teeth have exactly the same shape, volume, and number as the driving teeth. All the balancing teeth are evenly distributed on a circle with the same center as the center of the metal substrate and the same radius as the radius of the circle where the driving teeth are distributed. The adjacent balancing teeth differ by 180 / n degrees in direction; the balancing teeth and the closest driving teeth differ by 90 / n degrees in direction.

[0024] A design method for the stator structure of a standing-wave micromotor. Based on the stator structure of the standing-wave micromotor described above, a driving circuit is designed. And when the notch locking working mode is adopted, it includes the following steps:

[0025] Step 1, through the design of adjusting the stiffness of the column or the notch, and the balance design of the balancing teeth and the driving teeth, fix the position of the driving teeth at a layer of the wave crest during standing-wave driving, rather than at the position with the maximum vibration displacement. At the same time, design the two modal frequencies as close values. The designed numerical range of the close values is such that the frequency displacement resonators of the two modes can work within the bandwidth. With this structural design, a motor stator structure is obtained;

[0026] Step 2, based on the motor stator structure designed according to this structure, further design a forward and reverse driving circuit.

[0027] A preparation method of a stator structure of a standing wave micromotor, based on the stator structure of the standing wave micromotor described in any one of the above, and includes the following steps:

[0028] (a), Select a substrate material, which is a metal or a metal alloy, and the substrate material is a sheet, as the substrate;

[0029] (b), For the selected substrate material, process a convex structure by stamping, and the convex structure serves as the driving tooth;

[0030] (c), Grow a piezoelectric thin film on the substrate material, and the piezoelectric thin film serves as the piezoelectric layer;

[0031] (d), Grow an electrode structure on the substrate material;

[0032] (e), Form a notch or a mounting hole on the substrate material by cutting, and install a column on the edge of the mounting hole; the column or the notch is a working mode locking structure of the stator structure;

[0033] (f), Obtain a balance convex on the substrate material by processing, and the balance convex serves as the balance tooth.

[0034] Furthermore, it also includes the following steps:

[0035] After the stator structure is prepared in step (f), fabricate an integrated structure of the stator and the rotor; the integrated structure includes a friction layer and a magnetic material layer, the friction layer is in contact with the convex structure, and the magnetic material layer attracts the substrate material of the magnetic metal to provide the pre-tightening force necessary for friction drive; in the integrated structure of the stator and the rotor, when the square column is higher than or equal to the driving tooth, the corresponding position of the rotor needs to be cleared.

[0036] A preparation method of a stator structure of a standing wave micromotor, based on the stator structure of the standing wave micromotor described in any one of the above, includes the following steps:

[0037] First, select a substrate material, which is a metal or a metal alloy and is a sheet, as the substrate; grow a piezoelectric thin film on the substrate, and the piezoelectric thin film serves as the piezoelectric layer; grow an electrode structure on the substrate; at the same time, use another thin sheet structure to form a convex structure, a balance convex and a column convex by stamping or precision die-casting, the convex structure is the driving tooth, the balance convex is the balance tooth, the column convex is the column, and the column is the working mode locking structure of the stator structure;

[0038] Then, use bonding or welding to integrate the substrate with the piezoelectric thin film and the electrode structure grown thereon with the thin sheet structure formed with the convex structure, the balance convex and the column convex;

[0039] Finally, mounting holes are formed by cutting, and a shaft structure is installed in the mounting holes according to the application design. The method of installing the shaft structure includes any one of welding, interference fit, and bonding methods, thereby completing the processing and preparation of the stator structure.

[0040] Furthermore, it further includes the step of forming a notch by cutting, and the notch is a working mode locking structure of the stator structure.

[0041] A preparation method of a standing wave micromotor stator structure, based on the standing wave micromotor stator structure described in any one of the above, includes the following steps:

[0042] First, a substrate material is selected. The substrate material is a metal or a metal alloy and is a sheet, serving as the substrate. A piezoelectric thin film is grown on the substrate, and the piezoelectric thin film serves as the piezoelectric layer. An electrode structure is grown on the substrate. At the same time, using another thin sheet structure, a convex structure and a balance convex are formed by stamping or precision die-casting. The convex structure is a driving tooth, and the balance convex is a balance tooth.

[0043] Then, the substrate on which the piezoelectric thin film and the electrode structure are grown is integrated with the thin sheet structure on which the convex structure and the balance convex are formed by bonding or welding.

[0044] Finally, mounting holes and notches are formed by cutting. At the same time, a shaft structure is installed in the mounting holes according to the application design. The method of installing the shaft structure includes any one of welding, interference fit, and bonding methods. The notch is a working mode locking structure of the stator structure, thereby completing the processing and preparation of the stator structure.

[0045] A micromotor includes the standing wave micromotor stator structure described in any one of the above, and further includes a stator-rotor integrated structure. The integrated structure includes a friction layer and a magnetic material layer. The friction layer contacts the driving teeth, and the magnetic material layer attracts the substrate material of the magnetic metal to provide the pre-tightening force necessary for friction drive. When the square column locks the working mode and the square column is higher than the driving teeth, the corresponding position of the rotor needs to be clearanced.

[0046] The beneficial effects of the present invention include:

[0047] (1) The present invention uses balance teeth to offset the mass eccentricity caused by the driving teeth, thereby ensuring that the frequency difference between the clockwise mode and the counterclockwise mode is relatively small, and further greatly reducing the difficulty of frequency regulation of the driving circuit. The standing wave driving scheme based on the above structure only requires 1-way driving, and realizes forward and reverse rotation by switching the power supply of different sectors. Compared with the existing traveling wave driving scheme, the driving circuit is significantly simplified.

[0048] (2) The present invention uses cuts or columns to lock the shape of the working mode, ensuring that the driving teeth are located on the slope of the modal vibration shape, so that the driving teeth will definitely generate oblique movement, thus ensuring the necessary conditions for the rotation of the rotor. Further, through the design of fixing the anchor points or adjusting the cut stiffness, and the balance design of the balance teeth and the driving teeth, the position of the driving teeth during standing wave driving can be fixed at a layer of the wave crest instead of the position with the largest vibration displacement. At the same time, the two modal frequencies can be designed to be very close, so that the design of the frequency displacement resonators of the two modes is within the bandwidth. Accordingly, the driving circuit design required for the forward and reverse driving of the micromotor will also become simpler.

[0049] (3) The present invention proposes a new manufacturing method. The base structure is formed by stamping metal sheets and laser cutting, and the batch preparation cost is low. Batch preparation is achieved by first stamping and then depositing piezoelectric thin films. The base structure is formed by one-time stamping, avoiding the complex and expensive processes of multiple lithography and etching in the MEMS-based SOI bulk silicon process. One-time forming can also be used for batch preparation. At the same time, when the base material is a magnetic metal material, the application of the pre-tightening force and the detection of the rotation of the rotor can be achieved simultaneously through simple cooperation with the magnetic rotor. Description of the Drawings

[0050] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0051] Figure 1 Schematic diagram of using a cut to lock the working mode shape with the stator mode of Embodiment 1 being the B03 mode;

[0052] Figure 2 Schematic diagram of using a square column to lock the working mode shape with the stator mode of Embodiment 2 being the B03 mode;

[0053] Figure 3 Schematic diagram of using a cut to lock the working mode shape with the stator mode of Embodiment 3 being the B13 mode, where the number of nodal circles of this mode is equal to 1, the number of nodal diameters is equal to 3, and the shape of the driving teeth is cylindrical;

[0054] Figure 4 Schematic diagram of using a square column to lock the working mode shape with the stator mode of Embodiment 4 being the B13 mode, where the number of nodal circles of this mode is equal to 0 and the number of nodal diameters is equal to 3;

[0055] Figure 5For the stator mode of Example 5, the B13 mode is adopted. The number of nodal circles of this mode is equal to 1, the number of nodal diameters is equal to 3, the shape of the driving teeth is hemispherical, and it is a schematic diagram of the working mode shape locked by a notch;

[0056] Figure 6 For Figure 5 Schematic diagram of the working mode shape locked in the middle;

[0057] Figure 7 It is a flowchart of an embodiment of a preparation method;

[0058] Figure 8 It is a schematic diagram of the integrated structure manufacturing in an embodiment of a preparation method;

[0059] Figure 9 It is a flowchart of another embodiment of a preparation method;

[0060] Figure 10 It is a flowchart of yet another embodiment of a preparation method;

[0061] In the figure, 1 - metal substrate, 2 - driving teeth, 3 - balancing teeth, 4 - piezoelectric layer, 5 - notch, 6 - anchor point, 7 - columnar protrusion, 11 - base material, 12 - protrusion structure, 13 - PZT piezoelectric thin film, 14 - electrode structure, 15 - mounting hole, 16 - balancing protrusion, 31 - magnetic material, 32 - friction layer, 33 - thin sheet structure. Detailed implementation manners

[0062] All the features disclosed in all the embodiments in this specification, or all the steps in the methods or processes implicitly disclosed, except for mutually exclusive features and / or steps, can be combined and / or extended, replaced in any way.

[0063] In view of the current situation in the background, the inventors of this application further considered and believed that: in the existing solutions described in the background, mainly the traveling wave micromotor implementation scheme, the driving of the traveling wave is complex, at least two driving signals with a 90° phase difference are required, generally four driving signals with a 90° phase difference from each other are used for driving, and the driving circuit for generating multiple signals with a 90° phase difference is complex; moreover, based on the PZT - SOI MEMS process, the preparation is complex and requires multiple steps such as complex lithography and etching (at least 5 photomasks are required, including the PZT upper electrode pattern, PZT pattern, PZT lower electrode pattern, SOI top silicon pattern, and SOI bottom silicon pattern), so the process manufacturing cost is relatively high.

[0064] To further solve the above technical problems, the inventive concept of the present invention adopts standing wave drive, which only requires one-way drive. By switching the power supply of different sectors, forward and reverse rotation can be achieved, and different technical implementation ideas are proposed. Moreover, the base structure uses metal. The micromotor based on a metal substrate can be batch-produced by basic processes such as laser cutting, welding, and stamping, which can significantly reduce the manufacturing cost.

[0065] In a further technical concept, when the standing wave drive is adopted, the inventors of the present application have discovered the following new technical problems: how to achieve standing wave node diameter locking and forward and reverse mode matching in the structural design of the standing wave micromotor.

[0066] In a specific implementation solution, as the first aspect of the solution of the present application, the motor stator structure is improved. The motor stator of the present application includes a metal substrate (such as circular), drive teeth, balance teeth, and a piezoelectric layer. The drive teeth are in contact with the rotor, and the drive teeth drive the rotor to rotate through frictional force. The shapes of the drive teeth include hemispheres, semi-elliptical spheres, cylinders, square columns, cones, and columns with a polygon as the bottom surface. The number of drive teeth is closely related to the number of wave peaks of the stator working mode. If the number of working modes is n, the number of drive teeth is equal to 2*n. The shapes and volumes of all drive teeth are exactly the same, and all drive teeth are evenly distributed on a circle, with the center of the circle being the same as the center of the metal substrate. The adjacent drive teeth differ by 180 / n degrees in direction. The balance teeth are located on the back of the stator, and the function of the balance teeth is to offset the mass eccentricity caused by the drive teeth. The balance teeth have the same shape, volume, and number as the drive teeth. All balance teeth are evenly distributed on a circle, with the center of the circle being the same as the center of the metal substrate and the radius being the same as the radius of the drive tooth distribution circle. The adjacent balance teeth differ by 180 / n degrees in direction. The balance teeth and the closest drive tooth differ by 90 / n degrees in direction. The piezoelectric layer is located on the back of the stator, and the function of the piezoelectric layer is to convert electrical energy into mechanical energy, thereby driving the stator to vibrate according to the working mode. Cuts or columns are made on the metal substrate, and the function of the cuts or columns is to lock the shape of the stator working mode, ensure that the wave peaks of the clockwise working mode have the same direction as the cuts or columns, and ensure that the node diameters of the counterclockwise working mode have the same direction as the cuts or columns. The shapes of the cuts include squares, semi-circles, triangles, polygons, and the bottom surface shapes of the columns are squares, circles, triangles, polygons. The closest cut or square column to each drive tooth is located in the clockwise direction of the drive tooth.

[0067] The working principle of the motor stator structure of the present application is further described as follows:

[0068] In the clockwise mode, taking any crest or trough as a reference point, the driving tooth closest to this reference point is located in the clockwise direction of the reference point. When the excited stator vibrates in the clockwise mode, within the first half of each vibration cycle, the driving tooth near the crest moves obliquely in the clockwise direction, thus driving the rotor to rotate in the clockwise direction. Within the second half of each vibration cycle, the driving tooth near the trough moves obliquely in the clockwise direction, thus driving the rotor to rotate in the clockwise direction. In short, within the entire vibration cycle, the driving teeth drive the rotor to rotate in the clockwise direction.

[0069] In the counterclockwise mode, taking any crest or trough as a reference point, the driving tooth closest to this reference point is located in the counterclockwise direction of the reference point. When the excited stator vibrates in the counterclockwise mode, within the first half of each vibration cycle, the driving tooth near the crest moves obliquely in the counterclockwise direction, thus driving the rotor to rotate in the counterclockwise direction. Within the second half of each vibration cycle, the driving tooth near the trough moves obliquely in the counterclockwise direction, thus driving the rotor to rotate in the counterclockwise direction. In short, within the entire vibration cycle, the driving teeth drive the rotor to rotate in the counterclockwise direction.

[0070] The above-mentioned motor stator structure of the present invention uses balance teeth to offset the mass eccentricity caused by the driving teeth, thereby ensuring that the frequency difference between the clockwise mode and the counterclockwise mode is relatively small, and further greatly reducing the difficulty of frequency regulation of the driving circuit. The standing wave driving scheme based on the above structure only requires 1-way driving, and realizes forward and reverse rotation by switching the power supply of different sectors. Compared with the existing traveling wave driving scheme, the circuit complexity of generating the driving signal is significantly simplified.

[0071] In a further embodiment, the present invention also uses notches or columns to lock the shape of the working mode, ensuring that the driving teeth are located on the slope of the modal vibration shape, so that the driving teeth must generate oblique movement, thereby ensuring the necessary conditions for the rotation of the rotor.

[0072] It should be noted that in other deformation implementation schemes based on the above conceptions, ① the driving teeth and the balance teeth can be located on the same side of the stator; ② when using a square column to lock the mode, the square column can be on the same surface of the stator as the driving teeth, or on the other surface of the stator. The present invention provides the following various deformation embodiments, but is not limited thereto.

[0073] Embodiment 1: As Figure 1 shown, the stator mode adopts the B03 mode. The number of nodal circles of this mode is equal to 0, and the number of nodal diameters is equal to 3. Notches are used to lock the shape of the working mode.

[0074] The motor stator consists of a metal substrate 1, driving teeth 2, balancing teeth 3, and a piezoelectric layer 4. The metal substrate 1 is circular. The driving teeth 2 are located on the front side of the stator, and the front driving teeth are in contact with the rotor. The driving teeth 2 drive the rotor to rotate through friction. The shape of the driving teeth 2 is hemispherical. The number of driving teeth 2 is equal to six. The shapes and volumes of all driving teeth are exactly the same. All driving teeth are evenly distributed on a circle with a radius of 6100 um, and adjacent driving teeth differ by 60 degrees in direction. The balancing teeth 3 are located on the back side of the stator. The balancing teeth 3 have exactly the same shape, volume, and number as the driving teeth 2. All balancing teeth are evenly distributed on a circle with a radius of 6100 um, and adjacent balancing teeth differ by 60 degrees in direction. The balancing teeth differ by 30 degrees in direction from the closest driving teeth. The piezoelectric layer 4 is located on the back side of the stator. The function of the piezoelectric layer 4 is to convert electrical energy into mechanical energy, thereby driving the stator to vibrate according to the working mode. Square cuts are made on the metal substrate 1. The square cuts ensure that the wave peaks of the forward working mode have the same direction as the cuts, and the square cuts ensure that the nodal diameters of the reverse working mode have the same direction as the cuts. The driving teeth where the cuts are located are in the clockwise direction and differ by 15 degrees in angle.

[0075] Example 2: As Figure 2 shown, the stator mode adopts the B03 mode. The number of pitch circles of this mode is equal to 0, the number of nodal diameters is equal to 3, and a square column is used to lock the working mode shape.

[0076] The motor stator consists of a metal substrate 1, driving teeth 2, balancing teeth 3, and a piezoelectric layer 4. The metal substrate 1 is circular. The front driving teeth are in contact with the rotor. The driving teeth 2 drive the rotor to rotate through friction. The shape of the driving teeth 2 is hemispherical. The number of driving teeth 2 is equal to six. The shapes and volumes of all driving teeth are exactly the same. All driving teeth are evenly distributed on a circle with a radius of 6100 um, and adjacent driving teeth differ by 60 degrees in direction. The balancing teeth 3 are located on the back side of the stator. The balancing teeth 3 have exactly the same shape, volume, and number as the driving teeth 2. All balancing teeth are evenly distributed on a circle with a radius of 6100 um, and adjacent balancing teeth differ by 60 degrees in direction. The balancing teeth differ by 30 degrees in direction from the closest driving teeth. The piezoelectric layer 4 is located on the back side of the stator. The function of the piezoelectric layer 4 is to convert electrical energy into mechanical energy, thereby driving the stator to vibrate according to the working mode. Square columns are made on the metal substrate 1. The square columns ensure that the wave peaks of the clockwise working mode have the same direction as the square columns, and the square columns ensure that the nodal diameters of the counterclockwise working mode have the same direction as the square columns. The driving teeth where the square columns are located are in the clockwise direction and differ by 15 degrees in angle.

[0077] Example 3: As Figure 3 shown, the stator mode adopts the B13 mode. The number of pitch circles of this mode is equal to 1, the number of nodal diameters is equal to 3, and a cut is used to lock the working mode shape.

[0078] The motor stator is composed of a metal substrate 1, driving teeth 2, balancing teeth 3 and a piezoelectric layer 4. The metal substrate 1 is circular. The front driving teeth are in contact with the rotor. The driving teeth 2 drive the rotor to rotate through friction. The shape of the driving teeth 2 is cylindrical. The number of driving teeth 2 is equal to six. The shapes and volumes of all driving teeth are exactly the same. All driving teeth are evenly distributed on a circle with a radius equal to 4000um. The adjacent driving teeth differ by 60 degrees in direction. The balancing teeth 3 are located on the back of the stator. The balancing teeth 3 have the same shape, volume and number as the driving teeth 2. All balancing teeth 3 are evenly distributed on a circle with a radius equal to 4000um. The adjacent balancing teeth differ by 60 degrees in direction. The balancing teeth differ by 30 degrees in direction from the closest driving teeth. The piezoelectric layer 4 is located on the back of the stator. The function of the piezoelectric layer 4 is to convert electrical energy into mechanical energy, so as to drive the stator to vibrate according to the working mode. Square cuts are made on the metal substrate 1. The cuts ensure that the wave crest of the forward working mode has the same direction as the cuts, and the cuts ensure that the nodal diameter of the reverse working mode has the same direction as the cuts. The driving teeth where the cuts are located are in the clockwise direction and differ by 15 degrees in angle.

[0079] Embodiment 4: As Figure 4 shown, the stator mode adopts the B13 mode. The number of pitch circles of this mode is equal to 0, the number of nodal diameters is equal to 3, and the square column is used to lock the working mode shape.

[0080] The motor stator is composed of a metal substrate 1, driving teeth 2, balancing teeth 3 and a piezoelectric layer 4. The metal substrate 1 is circular. The front driving teeth are in contact with the rotor. The driving teeth 2 drive the rotor to rotate through friction. The shape of the driving teeth 2 is cylindrical. The number of driving teeth 2 is equal to six. The shapes and volumes of all driving teeth are exactly the same. All driving teeth are evenly distributed on a circle with a radius equal to 4000um. The adjacent driving teeth differ by 60 degrees in direction. The balancing teeth 3 are located on the back of the stator. The balancing teeth 3 have the same shape, volume and number as the driving teeth 2. All balancing teeth are evenly distributed on a circle with a radius equal to 4000um. The adjacent balancing teeth differ by 60 degrees in direction. The balancing teeth 3 differ by 30 degrees in direction from the closest driving teeth 2. The piezoelectric layer 4 is located on the back of the stator. The function of the piezoelectric layer 4 is to convert electrical energy into mechanical energy, so as to drive the stator to vibrate according to the working mode. Square columns are made on the metal substrate. The square columns ensure that the wave crest of the clockwise working mode has the same direction as the square columns, and the square columns ensure that the nodal diameter of the counterclockwise working mode has the same direction as the square columns. The driving teeth where the square columns are located are in the clockwise direction and differ by 15 degrees in angle.

[0081] Embodiment 5: As Figure 5 and Figure 6 shown, the stator mode adopts the B13 mode. The number of pitch circles of this mode is equal to 1, the number of nodal diameters is equal to 3, and the cut is used to lock the working mode shape.

[0082] The motor stator consists of a metal substrate 1, driving teeth 2, balancing teeth 3, and a piezoelectric layer 4. The metal substrate 1 is circular. The front driving teeth are in contact with the rotor, and the driving teeth 2 drive the rotor to rotate through frictional force. The shape of the driving teeth 2 is hemispherical. The number of driving teeth 2 is six, and all the driving teeth have exactly the same shape and volume. All the driving teeth are evenly distributed on a circle with a radius of 4500 um, and adjacent driving teeth differ by 60 degrees in direction. The balancing teeth 3 are located on the back of the stator. The balancing teeth 3 have exactly the same shape, volume, and number as the driving teeth 2. All the balancing teeth are evenly distributed on a circle with a radius of 4500 um, and adjacent balancing teeth differ by 60 degrees in direction. The balancing teeth differ by 30 degrees in direction from the closest driving teeth. The piezoelectric layer 4 is located on the back of the stator. The function of the piezoelectric layer 4 is to convert electrical energy into mechanical energy, thereby driving the stator to vibrate according to the working mode. Square cuts are made on the metal substrate 1. The cuts ensure that the wave peaks of the forward working mode have the same direction as the cuts, and the cuts ensure that the nodal diameters of the reverse working mode have the same direction as the cuts. The driving teeth where the cuts are located are in the clockwise direction and differ by 15 degrees in angle. An anchor point 6 is also provided in the middle of the disk. The anchor point located in the middle of the disk can minimize the loss of the anchor point and improve the Q value. At the same time, the cylinder of the anchor point can provide the function of a rotational constraint axis for the rotation of the rotor.

[0083] It should be particularly noted that the driving teeth 2 and the balancing teeth 3 can be located on the same layer of the stator. When the driving teeth 2 and the balancing teeth 3 are on the same side of the stator, in order to prevent the balancing teeth from interfering with the rotor drive, the balancing teeth 3 are lower in height than the driving teeth. The mass of the balancing teeth 3 should be comparable to that of the driving teeth in design and should not be too large or too small.

[0084] As the second aspect of this application, through the design of fixing the anchor point or adjusting the stiffness of the cuts, as well as the balance design of the balancing teeth and the driving teeth, the position of the driving teeth during standing wave drive can be fixed on the layer of the wave peak instead of the position with the largest vibration displacement. At the same time, the frequencies of the two modes can be designed to be very close, so that the frequency displacement resonator design of the two modes is within the bandwidth. Accordingly, the driving circuit design required for the forward and reverse drive of the micromotor will also become simpler.

[0085] As the third aspect of this application, a preparation method for the above-mentioned motor structure is provided. As an embodiment of the preparation method, as Figure 7 shown, it includes the following steps:

[0086] Step (a), select a substrate material 11 required for the thickness of the stator structure. According to the designed working frequency, the thickness range can be 0.1 - 0.5 mm, including but not limited to, the material can be a metal or metal alloy with a relatively high temperature resistance such as a stainless steel sheet or an iron-nickel alloy, which can withstand the temperature during the growth of the PZT thin film, about 500 °C.

[0087] Step (b): For the selected substrate material 11, a convex structure 12 is processed in the form of stamping to serve as a driving tooth.

[0088] Step (c): A PZT piezoelectric thin film 13 is grown by the sol-gel method or the magnetron sputtering method.

[0089] Step (d): A patterned metal electrode structure 14 is grown by the sputtering method.

[0090] Step (e): Mounting holes 15 are formed by laser cutting.

[0091] Step (f): The balance protrusions 16 on the back are obtained by processing methods such as welding, and the balance protrusions 16 serve as balance teeth.

[0092] After the stator is prepared, the stator-rotor integrated structure is as Figure 8 shown. 32 is a friction layer, and its material can be a wear-resistant non-metallic material such as engineering plastic PPS, etc. The 31 layer is a magnetic material, which can attract the substrate material 11 of the iron-nickel alloy to provide the pre-tightening force necessary for friction drive.

[0093] As another embodiment of the preparation method of the present invention, as Figure 9 shown, it includes the following steps:

[0094] First, select the substrate material 11 required for the stator structure thickness. According to the designed working frequency, the thickness range can be 0.1 - 0.5 mm, including but not limited to, its material can be a metal or metal alloy with relatively high temperature resistance such as stainless steel sheet, iron-nickel alloy, etc., which can withstand the temperature during the growth of the PZT thin film, about 500 °C; grow a PZT piezoelectric thin film 13 by the sol-gel method or the sputtering method (step a1); grow a patterned metal electrode structure 14 by the sputtering method (step b1); at the same time, use another thin sheet structure 33 (step a2), and form a convex structure 12, a balance protrusion 16 and a columnar protrusion 7 by stamping or precision die-casting (step b2);

[0095] Then, integrate the two structures formed in step b1 and step b2 by bonding or welding ( Figure 9 step c in);

[0096] Finally, form mounting holes 15 and cuts by laser cutting, thus completing the processing of the stator ( Figure 9 step d in). The method for installing the shaft structure includes any one of welding, interference fit, and bonding methods, but is not limited thereto.

[0097] As another embodiment of the preparation method of the present invention, as Figure 10 shown, it includes the following steps:

[0098] First, select the base material 11 required for the stator structure thickness. According to the designed operating frequency thickness range, it can be 0.1 - 0.5 mm, including but not limited to, the material can be metals or metal alloys with relatively high temperature resistance such as stainless steel sheets and iron-nickel alloys, which can withstand the temperature during the growth of the PZT thin film, about 500 °C; grow the PZT piezoelectric thin film 13 by the sol-gel method or sputtering method (step a1); sputter to grow the patterned metal electrode structure 14 (step b1); at the same time, use another thin sheet structure 33 (step a2), and form the convex structure 12 and the balance convex 16 by stamping or precision die-casting (step b2);

[0099] Then, integrate the two structures formed in step b1 and step b2 by bonding or welding ( Figure 9 step c) in);

[0100] Finally, form the mounting holes 15 and incisions by laser cutting to complete the processing of the stator ( Figure 9 step d) in). The method of installing the shaft structure includes any one of welding, interference fit, and bonding methods, but is not limited thereto.

[0101] It should be noted that in the manufacturing method part of the present invention, ① the base structure is formed by stamping metal sheets and laser cutting, and the batch preparation cost is low. Batch preparation is realized by first stamping and then depositing the PZT thin film. The base structure is formed by one-time stamping, avoiding the complex and expensive processes of multiple photolithography and etching in the SOI bulk silicon process based on MEMS, and one-time forming can also be used for batch preparation. ② When the base material 11 is a magnetic metal material such as iron-nickel alloy, a magnetic attraction force can be formed with the magnetic rotor to provide the pre-tightening force necessary for frictional drive; moreover, the magnetic rotor can provide a changing magnetic field during rotation, which can provide the necessary input for angle sensors such as magnetoresistance, so as to detect the rotation angle or speed of the rotor. That is, by simply cooperating with the magnetic rotor, the application of the pre-tightening force and the detection of the rotor rotation can be realized simultaneously.

[0102] As the fourth aspect of the present invention, a micro motor is also provided, including the standing wave micro motor stator structure described in any one of the above, and further including a stator-rotor integrated structure. The integrated structure includes a friction layer and a magnetic material layer. The friction layer contacts the driving teeth, and the magnetic material layer attracts the magnetic metal base material to provide the pre-tightening force necessary for frictional drive; when the square column locking working mode is adopted, and when the square column is higher than the driving teeth, the corresponding position of the rotor needs to be cleared.

[0103] The above description only relates to the technical principles and preferred embodiments employed in the present invention. Those skilled in the art can understand that the present invention is not limited to the specific embodiments described herein. Various obvious changes, adjustments, and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in relatively detail through the above embodiments, the present invention is not limited to the above embodiments only. Without departing from the principles and concepts of the present invention, it may also include more other equivalent embodiments, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A stator structure of a standing wave micromotor, characterized in that, Comprising: A substrate, driving teeth, balancing teeth, and a piezoelectric layer; The driving teeth, balancing teeth, and piezoelectric layer are all disposed on the substrate; the driving teeth are in contact with the rotor, and the driving teeth drive the rotor to rotate through frictional force; the balancing teeth are used to offset the mass eccentricity caused by the driving teeth; the piezoelectric layer is used to convert electrical energy into mechanical energy to drive the stator structure to vibrate according to the working mode; a locking structure is also fabricated on the substrate to lock the shape of the working mode of the stator structure, so that the driving teeth are located on the slope of the vibration shape of the working mode, and the driving teeth generate an oblique movement, ensuring that the wave crest of the clockwise working mode has the same direction as the locking structure, and ensuring that the nodal diameter of the counterclockwise working mode has the same direction as the locking structure.

2. The stator structure of the standing wave micromotor according to claim 1, characterized in that, The substrate includes a metal substrate or a metal alloy substrate.

3. The stator structure of the standing wave micromotor according to claim 1, characterized in that In the clockwise working mode, taking any wave crest or wave trough as a reference point, the driving tooth closest to this reference point is located in the clockwise direction of the reference point.

4. The standing wave micromotor stator structure according to claim 1, wherein, In the counterclockwise mode, taking any wave crest or wave trough as a reference point, the driving tooth closest to this reference point is located in the counterclockwise direction of the reference point.

5. The stator structure of the standing wave micromotor according to claim 1, characterized in that The locking structure includes notches and / or columns, and the notch or square column closest to each driving tooth is located in the clockwise direction of the driving tooth.

6. The stator structure of the standing wave micromotor according to claim 1, wherein, The driving teeth and the balancing teeth are located on the same side or different sides of the substrate; when the driving teeth and the balancing teeth are located on the same side of the substrate, the balancing teeth are lower in height than the driving teeth.

7. The stator structure of the standing wave micromotor according to claim 1, characterized in that The shape of the driving teeth includes any one of a hemisphere, a semi-elliptical sphere, a cylinder, a square column, a cone, and a column with a polygon bottom surface.

8. The stator structure of the standing wave micromotor according to claim 5, characterized in that The shape of the notch includes any one of a square, a semi-circle, a triangle, and a polygon; the bottom surface shape of the column includes any one of a square, a circle, a triangle, and a polygon.

9. The stator structure of the standing wave micromotor according to claim 5, characterized in that, When using a square column to lock the working mode, the square column and the driving teeth are located on the same surface or different surfaces of the substrate; when the driving teeth and the square column are located on the same surface of the substrate, the square column can be lower, higher, or equal in height to the driving teeth; among them, when the square column is higher than or equal to the driving teeth, the corresponding position of the rotor needs to be cleared.

10. The standing wave micromotor stator structure according to claim 5, characterized in that, An anchor point is provided at the center position of the substrate, and through the rotation axis of the anchor point, the function of providing a rotation constraint axis for the rotation of the rotor can be achieved.

11. The stator structure of the standing wave micromotor according to claim 2, characterized in that, The metal substrate includes a circular metal substrate; if the number of working modes is n, the number of driving teeth is equal to 2*n; the shapes and volumes of all driving teeth are the same, all driving teeth are evenly distributed on a circle, the center of the circle is the same as the center of the metal substrate, and the adjacent driving teeth differ by 180 / n degrees in direction; the balancing teeth have the same shape, volume, and number as the driving teeth, all balancing teeth are evenly distributed on a circle, the center of the circle is the same as the center of the metal substrate, the radius is the same as the radius of the driving tooth distribution circle, and the adjacent balancing teeth differ by 180 / n degrees in direction; the balancing teeth differ by 90 / n degrees in direction from the closest driving tooth.

12. A design method for a stator structure of a standing wave micromotor, characterized in that, Design a drive circuit based on the standing wave micromotor stator structure described in claim 10, and when using a notch to lock the working mode, it includes the following steps: Step 1: Through the design of adjusting the stiffness of the column or notch, and the balance design of the balance tooth and the driving tooth, fix the position of the driving tooth at the crest layer during standing-wave driving instead of at the position with the maximum vibration displacement. At the same time, design the two modal frequencies as close values, and the design value range of the close values is such that the frequency displacement resonators of the two modes can work within the bandwidth. With this structural design, a motor stator structure is obtained. Step 2: Based on the motor stator structure designed according to this structure, further design a forward and reverse drive circuit.

13. A preparation method for a stator structure of a standing wave micromotor, characterized in that, Based on the standing-wave micromotor stator structure described in any one of claims 1 to 11, and comprising the following steps: (a) Select a substrate material, which is a metal or metal alloy, and the substrate material is a sheet, as the substrate; (b) For the selected substrate material, process a convex structure in the form of stamping, and the convex structure serves as the driving tooth; (c) Grow a piezoelectric thin film on the substrate material, and the piezoelectric thin film serves as the piezoelectric layer; (d) Grow an electrode structure on the substrate material; (e) Form mounting holes on the substrate material by cutting, and install columns at the edges of the mounting holes and / or form notches on the substrate material; the columns and / or notches serve as the working mode locking structure of the stator structure; (f) Obtain balance protrusions by processing on the substrate material, and the balance protrusions serve as the balance teeth.

14. The preparation method of the standing wave micromotor stator structure according to claim 13, characterized in that, It further comprises the following steps: After the stator structure is prepared in step (f), fabricate a stator-rotor integrated structure; this integrated structure includes a friction layer and a magnetic material layer, the friction layer contacts the convex structure, and the magnetic material layer attracts the substrate material of the magnetic metal to provide the pre-tightening force necessary for friction drive; when the square column is higher than or equal to the driving tooth, the corresponding position of the rotor needs to be clear.

15. A preparation method for a stator structure of a standing wave micromotor, characterized in that, Based on the standing-wave micromotor stator structure described in any one of claims 1 to 11, it includes the following steps: First, select a substrate material, which is a metal or metal alloy and is a sheet, as the substrate; grow a piezoelectric thin film on the substrate, and the piezoelectric thin film serves as the piezoelectric layer; grow an electrode structure on the substrate; at the same time, use another thin sheet structure to form a convex structure, a balance protrusion, and a column protrusion by stamping or precision die-casting. The convex structure is the driving tooth, the balance protrusion is the balance tooth, and the column protrusion is the column. The column is the working mode locking structure of the stator structure; Then, integrate the substrate grown with the piezoelectric thin film and the electrode structure with the thin sheet structure formed with the convex structure, the balance protrusion, and the column protrusion by bonding or welding; Finally, form mounting holes by cutting, and at the same time install a shaft structure in the mounting holes according to the application design. The method of installing the shaft structure includes any one of welding, interference fit, and bonding methods; thus, the processing and preparation of the stator structure are completed.

16. The preparation method of the standing wave micromotor stator structure according to claim 15, characterized in that, It further includes the step: forming a notch by cutting, and the notch is the working mode locking structure of the stator structure.

17. A preparation method for a stator structure of a standing wave micromotor, characterized in that, Based on the standing-wave micromotor stator structure described in any one of claims 1 to 11, it includes the following steps: First, select a substrate material, which is a metal or metal alloy and is in the form of a sheet, as the substrate; grow a piezoelectric thin film on the substrate, and the piezoelectric thin film serves as the piezoelectric layer; grow an electrode structure on the substrate; at the same time, use another thin sheet structure to form a convex structure and a balance convex by stamping or precision die-casting, the convex structure is a driving tooth, and the balance convex is a balance tooth; Then, integrate the substrate with the piezoelectric thin film and the electrode structure grown thereon and the thin sheet structure with the convex structure and the balance convex formed thereon by bonding or welding; Finally, form mounting holes and cuts by cutting, and at the same time install a shaft structure in the mounting holes according to the application design, and the method of installing the shaft structure includes any one of welding, interference fit, and bonding methods; the cut is a working mode locking structure of the stator structure, thus completing the processing and preparation of the stator structure.

18. A micro motor, characterized in that, It includes the standing wave micromotor stator structure according to any one of claims 1-11, and further includes a stator-rotor integrated structure, which includes a friction layer and a magnetic material layer. The friction layer is in contact with the driving teeth, and the magnetic material layer attracts the substrate material of the magnetic metal to provide the pre-tightening force necessary for friction drive; When the square column is used to lock the working mode and the square column is higher than the driving teeth, the corresponding position of the rotor needs to be cleared.

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