Traveling wave type ultrasonic motor stator assembly based on multi-partition piezoelectric bimorph and electric excitation method thereof

Abstract

The invention relates to a traveling wave type ultrasonic motor stator assembly based on a multi-partition piezoelectric bimorph and an electric excitation method of the traveling wave type ultrasonic motor stator assembly, and one surface of the multi-partition piezoelectric bimorph is connected with a stator substrate to excite a stator elastomer to vibrate so as to realize a driving function. The multi-partition piezoelectric bimorph comprises a first piezoelectric ceramic piece, a flexible printed board and a second piezoelectric ceramic piece; the two sides of the flexible printed board are attached to the front face of the first piezoelectric ceramic piece and the front face of the second piezoelectric ceramic piece respectively. The stator substrate, a ground wire wiring hole of the flexible printed board, a ground wire of the first piezoelectric ceramic piece and a ground wire of the second piezoelectric ceramic piece are sequentially connected in series and grounded. Electric field signals are transmitted to the first piezoelectric ceramic piece and the second piezoelectric ceramic piece by applying voltage with the time difference of pi / 2 to the flexible printed board, so that the multi-partition piezoelectric bimorph generates mechanical motion to excite stator vibration, and low-voltage driving can be achieved on the premise that the output performance of the motor is improved.

Description

Technical Field

[0001] The invention relates to a traveling wave type ultrasonic motor stator component based on a multi-partition piezoelectric bimorph and an electrical excitation method thereof, belonging to the field of ultrasonic motors. Background Art

[0002] Ultrasonic motor is a new type of motor that uses the inverse piezoelectric effect of piezoelectric materials to stimulate the stator to vibrate slightly in the ultrasonic frequency band, thereby forming a specific motion trajectory on the stator surface and realizing mechanical-electrical energy conversion through friction. According to the driving principle of ultrasonic motors, they are divided into standing wave ultrasonic motors, traveling wave ultrasonic motors and composite ultrasonic motors. Among them, the traveling wave ultrasonic motor uses the wave excited in the stator to make the elastic body drive the surface particles to obtain an elliptical trajectory vibration with a driving effect.

[0003] At present, the more common traveling wave ultrasonic motor adopts a single ceramic sheet structure. For example, the invention with application number 201610615815.X discloses a high-speed rotating ultrasonic motor and its stator electrical excitation method. The motor stator body is composed of a metal disc and a carbon fiber tube, including a metal disc, a carbon fiber tube and a piezoelectric ceramic; four ceramic sheets are used to excite two out-of-plane bending working modes with a spatial phase difference of π / 2 on the lower end face of the stator; two sinusoidal signals with a time phase difference of π / 2 are used to simultaneously excite these two orthogonal working modes, so that elliptical motion is generated on the inner inclined surfaces at both ends of the carbon fiber tube, and the rotor is driven to move by friction. However, in order to produce a certain degree of deformation and output force, a single ceramic sheet usually requires a higher driving voltage. In this regard, the invention with application number 202111504110.8 discloses a hollow rotary traveling wave ultrasonic motor, which replaces the traditional annular partitioned polarized piezoelectric ceramic sheet with a thicker fan-shaped ceramic sheet, and changes the patch form into a sandwich form, making full use of the advantages of the larger d33 constant of piezoelectric ceramics, further improving the electromechanical coupling efficiency of the motor, and enhancing the mechanical output capacity of the motor; however, the block-structured ceramic sheets will lead to complicated wiring and it is difficult to ensure the integrity.

[0004] Inspired by the piezoelectric stack, the so-called piezoelectric stack structure includes multiple layers of piezoelectric ceramic sheets, which are formed by a stacking bonding and co-firing process, and can produce a large displacement output, fast response, and achieve low-voltage drive. Drawing on the existing stable performance of the traveling wave ultrasonic motor, professional technicians in this field envision the use of a multi-partitioned piezoelectric dual-chip form to increase the output performance of the motor and achieve the purpose of low-voltage drive while ensuring the overall design. Summary of the invention

[0005] The present invention provides a traveling wave ultrasonic motor stator assembly based on a multi-partition piezoelectric bimorph and an electrical excitation method thereof. Through a special electrical excitation method, the amplitude of the motor can be increased while the output of the motor can be increased, thereby realizing low-voltage driving.

[0006] The technical solution adopted by the present invention to solve the technical problem is:

[0007] A traveling wave ultrasonic motor stator assembly based on a multi-partition piezoelectric bimorph comprises a stator and a multi-partition piezoelectric bimorph, wherein the multi-partition piezoelectric bimorph comprises a first piezoelectric ceramic sheet, a flexible printed circuit board and a second piezoelectric ceramic sheet;

[0008] The first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are both annular structures with a multi-partition structure, and the portion where the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are provided with the multi-partition structure is defined as the front side. The first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are coaxially arranged on two sides of the flexible printed circuit board, respectively, and the two sides of the flexible printed circuit board are respectively attached to the front side of the first piezoelectric ceramic sheet and the front side of the second piezoelectric ceramic sheet;

[0009] The stator is coaxially arranged on the back of the first piezoelectric ceramic sheet, the ground wires on the front and back of the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are connected, and the conductive areas on the front and back of the flexible printed board are connected; the stator substrate, the ground wire connection hole of the flexible printed board, the ground wire of the first piezoelectric ceramic sheet and the ground wire of the second piezoelectric ceramic sheet are connected to the ground in series in sequence;

[0010] By applying a voltage with a time difference of π / 2 to the flexible printed circuit board, the electric field signal is transmitted to the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet, so that the multi-partitioned piezoelectric bimorph generates mechanical movement to excite the stator vibration and drive the motor to rotate;

[0011] Furthermore, the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet have the same multi-partition structure, both including phase A, phase B, an unpolarized region and a ground line, and are distributed in the order of phase A, ground line, phase B, and unpolarized region along the circular ring of the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet, with a line passing through the ground line, the center of the circular ring, and the center of the unpolarized region as a symmetry line, and phase A is symmetrical with phase B; and both phase A and phase B include a plurality of alternately placed forward-polarized piezoelectric ceramic sheets and reverse-polarized piezoelectric ceramic sheets;

[0012] When the front surface of the first piezoelectric ceramic sheet and the front surface of the second piezoelectric ceramic sheet are arranged relative to the flexible printed circuit board at the same time, the first piezoelectric ceramic sheet A phase is connected to the second piezoelectric ceramic sheet B phase to form the piezoelectric bimorph A phase, and the first piezoelectric ceramic sheet B phase is connected to the second piezoelectric ceramic sheet A phase to form the piezoelectric bimorph B phase;

[0013] Furthermore, the ground wires on the front and back sides of the first piezoelectric ceramic sheet are connected by plating a conductive material on the outer diameter edge of the first piezoelectric ceramic sheet; similarly, the ground wires on the front and back sides of the second piezoelectric ceramic sheet are connected by plating a conductive material on the outer diameter edge of the first piezoelectric ceramic sheet;

[0014] Furthermore, when the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are coaxially arranged on both sides of the flexible printed board, the ground wire of the first piezoelectric ceramic sheet, the ground wire of the second piezoelectric ceramic sheet and the ground wire of the flexible printed board are aligned and arranged;

[0015] Furthermore, the two sides of the flexible printed circuit board have the same structure, and are both provided with a conductive area, a non-conductive area and a wiring hole, and the conductive area is connected by plating a conductive material at the wiring hole position; wherein the wiring holes of the flexible printed circuit board include an A-phase wiring hole, a B-phase wiring hole and a ground wiring hole;

[0016] An electrical excitation method for a traveling wave ultrasonic motor stator assembly based on a multi-partitioned piezoelectric bimorph, when two sides of a flexible printed circuit board are respectively attached to the front side of a first piezoelectric ceramic sheet and the front side of a second piezoelectric ceramic sheet, the A phase of the first piezoelectric ceramic sheet is arranged relative to the B phase of the second piezoelectric ceramic sheet, the B phase of the first piezoelectric ceramic sheet and the A phase of the second piezoelectric ceramic sheet are arranged relative to each other, the polarization directions of the A phase of the first piezoelectric ceramic sheet and the B phase of the second piezoelectric ceramic sheet are set opposite, and the polarization directions of the B phase of the first piezoelectric ceramic sheet and the A phase of the second piezoelectric ceramic sheet are set opposite;

[0017] The multi-zone piezoelectric bimorph adopts the d31 working mode to excite the corresponding working mode;

[0018] Furthermore, the excitation method is specifically as follows: the ground wire connection hole of the flexible printed circuit board is connected separately, the electrical signal is divided into two phases, a sin(ωt) signal is applied to the A-phase connection hole of the flexible printed circuit board, and a sin(ωt+π / 2) signal is applied to the B-phase connection hole of the flexible printed circuit board. At this time, the two-phase signals differ by π / 2; when the two-phase signals differ by -π / 2, the rotation direction of the motor changes.

[0019] Through the above technical solution, compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The traveling wave ultrasonic motor stator assembly based on multi-partition piezoelectric bimorph provided by the present invention adopts a parallel piezoelectric bimorph structure, that is, one or two surfaces of the piezoelectric bimorph are interconnected with the metal elastic body to excite the vibration of the stator elastic body to realize the driving function, and can achieve low voltage output;

[0021] 2. The traveling wave ultrasonic motor stator assembly based on multi-partition piezoelectric bimorph provided by the present invention adopts a series grounding method, which avoids the complexity of wiring, facilitates installation, and ensures the integrity of the design;

[0022] 3. The present invention provides an electrical excitation method for a traveling wave ultrasonic motor stator assembly based on a multi-partitioned piezoelectric dual-chip, which uses thinned stator dual ceramic sheets with opposite polarization directions, and can achieve the effects of amplitude amplification, speed increase, and torque amplification, ultimately achieving the purpose of performance improvement and low-voltage drive. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0024] Figure 1 It is a schematic diagram of the overall structure provided by the present invention;

[0025] Figure 2 is a schematic structural diagram of a first piezoelectric ceramic sheet provided by the present invention;

[0026] Figure 3 is a schematic structural diagram of a second piezoelectric ceramic sheet provided by the present invention;

[0027] Figure 4 It is a structural schematic diagram of a flexible printed circuit board provided by the present invention;

[0028] Figure 5 It is a schematic diagram of connecting the front and back ground wires of the first piezoelectric ceramic sheet provided by the present invention;

[0029] Figure 6 It is a relative position diagram of the multi-partition piezoelectric bimorph provided by the present invention;

[0030] Figure 7 is a schematic diagram of the electrical excitation method provided by the present invention;

[0031] Figure 8 This is a schematic diagram of traveling wave and harmonic response analysis using a single ceramic piece of the original stator provided in Example 1 of the present invention;

[0032] Fig. 9 This is a schematic diagram of the analysis of traveling waves and harmonic responses of the original stator dual ceramic sheets with the same polarization direction provided by the second embodiment of the present invention;

[0033] Fig.10 This is a schematic diagram of Example 3 provided by the present invention regarding the use of traveling waves with opposite polarization directions of the original stator double ceramic sheets and harmonic response analysis;

[0034] Fig.11 This is a schematic diagram of the analysis of traveling waves and harmonic responses of dual ceramic sheets with the same polarization direction using thinned stators provided by the present invention in Example 4;

[0035] Fig.12 This is a schematic diagram of Example 5 provided by the present invention regarding the analysis of traveling waves and harmonic responses using thin stator dual ceramic sheets with opposite polarization directions.

[0036] In the figure: 1 is the stator,

[0037] 2 is a multi-partition piezoelectric bimorph.

[0038] 21 is a first piezoelectric ceramic sheet, 211 is a front surface of the first piezoelectric ceramic sheet, 212 is a back surface of the first piezoelectric ceramic sheet, 213 is a ground line of the first piezoelectric ceramic sheet, 214 is a front surface and a back surface of the first piezoelectric ceramic sheet,

[0039] 22 is the second piezoelectric ceramic sheet, 221 is the front surface of the second piezoelectric ceramic sheet, 222 is the back surface of the second piezoelectric ceramic sheet, 223 is the ground wire of the second piezoelectric ceramic sheet,

[0040] 23 is a flexible printed circuit board, 231 is a non-conductive area, 232 is a front conductive area, 2321 is a front A-phase conductive area, 2322 is a front B-phase conductive area, 2323 is a front ground wire, 233 is a wiring hole, 2331 is an A-phase wiring hole, 2332 is a B-phase wiring hole, 2333 is a ground wiring hole, 234 is a back conductive area, 2341 is a back A-phase conductive area, 2342 is a back B-phase conductive area, and 2343 is a back ground wire. DETAILED DESCRIPTION

[0041] The present invention will now be described in further detail with reference to the accompanying drawings. In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "left side", "right side", "upper part", "lower part", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and "first", "second", etc. do not indicate the importance of the components, and therefore cannot be understood as a limitation on the present invention. The specific dimensions used in this embodiment are only for illustrating the technical solution by example, and do not limit the scope of protection of the present invention.

[0042] As described in the background technology, professional technicians in this field, inspired by piezoelectric stacks and combining with existing stable performance traveling wave ultrasonic motors, have conceived the use of a multi-partitioned piezoelectric dual chip form. It should be noted here that the traditional piezoelectric dual chip structure is usually a whole, without clear partition divisions, and the entire dual chip deforms and responds as a single unit when working. Its function is relatively simple and can only achieve overall deformation such as bending or stretching. The movement and response mode is relatively fixed. Therefore, traditional piezoelectric dual chips are commonly seen in some simple sensors, drivers, etc. The traveling wave ultrasonic motor stator assembly that this application hopes to provide can achieve complex motion modes. Based on this premise, a multi-partitioned piezoelectric dual chip is studied and adopted, which is divided into multiple independent partitions. These partitions can be applied and driven in different modes according to actual needs.

[0043] like Figure 1As shown, the specific structure of the stator assembly of the traveling wave ultrasonic motor based on the multi-partition piezoelectric bimorph provided by the present application includes a stator 1, and also includes a multi-partition piezoelectric bimorph 2, wherein the multi-partition piezoelectric bimorph includes a first piezoelectric ceramic sheet 21, a flexible printed board 23, and a second piezoelectric ceramic sheet 22; the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are both annular structures of a multi-partition structure, using the same PZT material and the partitions are symmetrically distributed. The part where the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are arranged in a multi-partition structure is defined as the front side (the front side 211 of the first piezoelectric ceramic sheet and the front side 221 of the second piezoelectric ceramic sheet, and the matching, the back side 212 of the first piezoelectric ceramic sheet and the back side 222 of the second piezoelectric ceramic sheet), the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are coaxially arranged on both sides of the flexible printed board, and the two sides of the flexible printed board are respectively attached to the front side of the first piezoelectric ceramic sheet and the front side of the second piezoelectric ceramic sheet.

[0044] As the first innovation of the present application, the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are provided with a multi-partition structure, such as Figure 2-Figure 3 As shown, the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet have the same multi-partition structure, both including phase A, phase B, an unpolarized region and a ground wire (ground wire 213 of the first piezoelectric ceramic sheet and ground wire 223 of the second piezoelectric ceramic sheet). The phase A, the ground wire, the phase B and the unpolarized region are distributed in the order of the circular ring of the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet, and the line passing through the ground wire, the center of the circular ring and the center of the unpolarized region is taken as the symmetry line, and the phase A is symmetrical with the phase B; wherein the phase A and the phase B both include a plurality of alternately placed forwardly polarized piezoelectric ceramic sheets and reversely polarized piezoelectric ceramic sheets.

[0045] It should be noted that the number of partitions of the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet is designed according to actual needs. Figure 2-Figure 3 The setting method in depends on the diameter of the stator and the number of waveforms of the stator. The design of multi-partition piezoelectric bimorph can achieve multiple vibration modes by applying modalities of different partitions to adapt to different working conditions and load changes, greatly expanding the application range and adaptability of the motor. It can generate stronger vibration and driving force, so that the motor has higher output power, speed and precision, and is suitable for high-end equipment and precision instruments with high requirements for motor performance.

[0046] In the traditional piezoelectric dual-chip structure, the elastomer directly connects the two ceramic sheets as an intermediate layer in the piezoelectric dual-chip structure, so that the entire structure becomes a whole. Its parameters such as thickness and elastic modulus will affect the mechanical properties of the piezoelectric dual-chip. By selecting elastomers with different characteristics, the performance of the dual-chip can be adjusted to adapt to different application scenarios, that is, the elastomer between the two ceramic sheets is used to vibrate to work. In this application, the stator is coaxially arranged on the back of the first piezoelectric ceramic sheet, that is, one or two surfaces of the piezoelectric dual-chip are interconnected with the metal elastomer, and a flexible printed circuit board is arranged in the middle of the piezoelectric dual-chip. When the flexible printed circuit board is placed in the middle of the piezoelectric dual-chip, it is not directly connected to the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet, but is connected to the electrodes on the ceramic sheet through the conductive layer on its surface to achieve the application and control of the electric field. It is more from the perspective of circuit control and signal transmission, and can realize the application of modes to piezoelectric ceramic sheets in different areas, and then control the electric field, so that the piezoelectric dual-chip can produce more complex and accurate deformation modes and motion trajectories. Obviously, the multi-partitioned piezoelectric dual chip provided by this application is more suitable for fields with extremely high requirements for precision and flexibility.

[0047] The above-mentioned piezoelectric bimorph structure can achieve low voltage output because the bimorphs provided in this application are mechanically connected in series but electrically connected in parallel. We assume that each bimorph unit has the same voltage when connected in parallel, but the current is distributed among the units. According to the definition of capacitance:

[0048]

[0049] In the above formula, ε 0 is the permittivity of vacuum (unit: F / m), A is the electrode area, d i is the electrode spacing of the ith unit.

[0050] Since it is connected in parallel, the voltage V i Same, so V i =V.

[0051] According to Ohm's law, the current I i With voltage V i , capacitor C i The relationship between them is:

[0052]

[0053] Since the voltage is the same in the parallel circuit, the current of each unit can be added to get the total current: I = ∑I i ; Obviously, for a parallel circuit, the current increases at the same voltage, and the voltage is still output as a low voltage.

[0054] The ground wires on the front and back sides of the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are connected. Specifically, Figure 5 As shown, the ground wires on the front and back sides 214 of the first piezoelectric ceramic sheet are connected by plating conductive material on the outer edge of the first piezoelectric ceramic sheet; similarly, the ground wires on the front and back sides of the second piezoelectric ceramic sheet are connected by plating conductive material on the outer edge of the first piezoelectric ceramic sheet.

[0055] The two sides of the flexible printed circuit board have the same structure, both of which are provided with a conductive area, a non-conductive area and a wiring hole. The conductive areas on the front and back of the flexible printed circuit board are connected, and the conductive areas are connected by plating conductive materials at the wiring hole positions; Figure 4 As shown, the flexible printed circuit board specifically includes a non-conductive area 231, a front conductive area 232, a back conductive area 234 and a wiring hole 233. The front conductive area 232 includes a front A-phase conductive area 2321, a front B-phase conductive area 2322 and a front ground wire 2323. The wiring hole 233 includes an A-phase wiring hole 2331, a B-phase wiring hole 2332 and a ground wire wiring hole 2333. The back conductive area 234 includes a back A-phase conductive area 2341, a back B-phase conductive area 2342 and a back ground wire 2343. The front A-phase conductive area 2321 and the back A-phase conductive area 2341 are connected on the front and back sides by plating conductive material at the A-phase wiring hole 2331. Similarly, the front B-phase conductive area and the back B-phase conductive area 2342 are connected in the same way.

[0056] As another innovative point of this application, Figure 6 As shown, the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are placed face to face, that is, the first piezoelectric ceramic sheet A phase is connected to the second piezoelectric ceramic sheet B phase to form the piezoelectric bimorph A phase; the first piezoelectric ceramic sheet B phase is connected to the second piezoelectric ceramic sheet A phase to form the piezoelectric bimorph B phase, and when the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are coaxially arranged on both sides of the flexible printed circuit board, the ground wire of the first piezoelectric ceramic sheet, the ground wire of the second piezoelectric ceramic sheet and the ground wire of the flexible printed circuit board are aligned; the stator substrate, the ground wire connection hole of the flexible printed circuit board, the ground wire of the first piezoelectric ceramic sheet and the ground wire of the second piezoelectric ceramic sheet are connected to the ground in series in sequence to ensure the normal operation of the motor; the series grounding method is different from the traditional power-on method and can ensure the overall design.

[0057] The present application continues to provide an electrical excitation method for a traveling wave ultrasonic motor stator assembly based on a multi-partition piezoelectric dual chip. The multi-partition piezoelectric dual chip adopts a d31 working mode to excite the corresponding working mode.

[0058] The ground wire connection hole of the flexible printed circuit board is connected separately to divide the electrical signal into two phases. Since the two sides of the flexible printed circuit board are respectively attached to the front side of the first piezoelectric ceramic sheet and the front side of the second piezoelectric ceramic sheet, Figure 6As shown, the A phase of the first piezoelectric ceramic sheet is opposite to the B phase of the second piezoelectric ceramic sheet, and the B phase of the first piezoelectric ceramic sheet is opposite to the A phase of the second piezoelectric ceramic sheet. Therefore, the polarization directions of the A phase of the first piezoelectric ceramic sheet and the B phase of the second piezoelectric ceramic sheet are set to be opposite, and the polarization directions of the B phase of the first piezoelectric ceramic sheet and the A phase of the second piezoelectric ceramic sheet are opposite. Figure 7 As shown in the figure, a sin(ωt) signal is applied to the A-phase wiring hole of the flexible printed circuit board, and a sin(ωt+π / 2) signal is applied to the B-phase wiring hole of the flexible printed circuit board. At this time, the two-phase signals differ by π / 2; when the two-phase signals differ by -π / 2, the rotation direction of the motor changes. That is, by applying a voltage with a time difference of π / 2 to the flexible printed circuit board, the electric field signal is transmitted to the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet, so that the multi-partitioned piezoelectric bimorph generates mechanical motion to excite the stator vibration and drive the motor to rotate.

[0059] The electric excitation method provided by the present application is to apply the polarization direction of the thinned stator dual ceramic sheets in opposite directions, which can achieve the purpose of maximum amplitude, ultimately improve performance and low voltage drive. The applicant has conducted experimental verification and provided Examples 1, 2, 3, 4 and 5.

[0060] Example 1 uses the original stator single ceramic sheet:

[0061] Traveling wave and harmonic response analysis diagrams are shown in Figure 2. Figure 8 As shown, the frequency of the 60 original stator single ceramic pieces is set to 39800HZ, and the amplitude is 2.8μm.

[0062] Example 2 uses the same polarization direction of the original stator double ceramic sheets:

[0063] Traveling wave and harmonic response analysis diagrams are shown in Figure 2. Fig. 9 As shown, the frequency of the 60 stator dual ceramic sheets with the same polarization direction (one extension and one contraction) is set to 43300HZ, and the amplitude is 0.25μm.

[0064] Example 3 uses the original stator double ceramic sheets with opposite polarization directions:

[0065] Traveling wave and harmonic response analysis diagrams are shown in Figure 2. Fig.10 As shown, the frequency of the 60 stator dual ceramic sheets with opposite polarization directions (same extension and same contraction) is set to 43300 Hz, and the amplitude is 3.65 μm.

[0066] Example 4 uses thinned stator dual ceramic sheets with the same polarization direction:

[0067] Traveling wave and harmonic response analysis diagrams are shown in Figure 2. Fig.11 As shown, the frequency of the 60-thin stator dual ceramic sheets with the same polarization direction (one extension and one contraction) is set to 38100 Hz, and the amplitude is 0.16 μm.

[0068] Example 5 uses a thinned stator with two ceramic sheets with opposite polarization directions:

[0069] Traveling wave and harmonic response analysis diagrams are shown in Figure 2. Fig.12 As shown, the frequency of the polarization directions of the 60-thin stator dual ceramic sheets in opposite directions (expanding and contracting at the same time) is set to 38100 Hz, and the amplitude is 4.6 μm.

[0070] The data of Examples 1-5 are summarized in Table 1:

[0071] Table 1

[0072]

[0073] It can be seen from this that the amplitude of the thinned stator dual ceramic sheets with opposite polarization directions provided by the present application is the largest.

[0074] 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 to which this application 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.

[0075] The meaning of "and / or" described in this application means that the situations where each exists alone or both exist at the same time are included.

[0076] The term “connection” as used in this application may mean a direct connection between components or an indirect connection between components via other components.

[0077] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A traveling wave ultrasonic motor stator assembly based on a multi-partitioned piezoelectric bimorph, comprising a stator, characterized in that: Also included is a multi-partitioned piezoelectric bimorph, wherein the multi-partitioned piezoelectric bimorph includes a first piezoelectric ceramic sheet, a flexible printed circuit board, and a second piezoelectric ceramic sheet; The first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are both annular structures with a multi-partition structure, and the portion where the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are provided with the multi-partition structure is defined as the front side. The first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are coaxially arranged on two sides of the flexible printed circuit board, respectively, and the two sides of the flexible printed circuit board are respectively attached to the front side of the first piezoelectric ceramic sheet and the front side of the second piezoelectric ceramic sheet; The stator is coaxially arranged on the back of the first piezoelectric ceramic sheet, the ground wires on the front and back of the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are connected, and the conductive areas on the front and back of the flexible printed board are connected; the stator substrate, the ground wire connection hole of the flexible printed board, the ground wire of the first piezoelectric ceramic sheet and the ground wire of the second piezoelectric ceramic sheet are connected to the ground in series in sequence; By applying a voltage with a time difference of π / 2 to the flexible printed circuit board, the electric field signal is transmitted to the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet, so that the multi-partitioned piezoelectric dual crystal generates mechanical movement to excite the stator vibration and drive the motor to rotate.

2. The traveling wave ultrasonic motor stator assembly based on multi-partitioned piezoelectric bimorph according to claim 1 is characterized in that: The first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet have the same multi-partition structure, both including phase A, phase B, an unpolarized region and a ground line, and are distributed in the order of phase A, ground line, phase B and unpolarized region along the annular shape of the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet, with a line passing through the ground line, the center of the annular shape and the center of the unpolarized region as a symmetry line, and phase A is symmetrical with phase B; and both phase A and phase B include a plurality of alternately placed forward polarized piezoelectric ceramic sheets and reverse polarized piezoelectric ceramic sheets; Among them, when the front side of the first piezoelectric ceramic sheet and the front side of the second piezoelectric ceramic sheet are arranged relative to the flexible printed circuit board at the same time, the first piezoelectric ceramic sheet A phase is connected to the second piezoelectric ceramic sheet B phase to form the piezoelectric dual-chip A phase, and the first piezoelectric ceramic sheet B phase is connected to the second piezoelectric ceramic sheet A phase to form the piezoelectric dual-chip B phase.

3. The traveling wave ultrasonic motor stator assembly based on multi-partitioned piezoelectric bimorph according to claim 1 is characterized in that: The ground wires on the front and back sides of the first piezoelectric ceramic sheet are connected by plating conductive material on the outer edge of the first piezoelectric ceramic sheet; similarly, the ground wires on the front and back sides of the second piezoelectric ceramic sheet are connected by plating conductive material on the outer edge of the first piezoelectric ceramic sheet.

4. The traveling wave ultrasonic motor stator assembly based on multi-partitioned piezoelectric bimorph according to claim 1 is characterized in that: When the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are coaxially arranged on both sides of the flexible printed board, the ground wire of the first piezoelectric ceramic sheet, the ground wire of the second piezoelectric ceramic sheet and the ground wire of the flexible printed board are aligned.

5. The traveling wave ultrasonic motor stator assembly based on multi-partitioned piezoelectric bimorph according to claim 1 is characterized in that: The two sides of the flexible printed circuit board have the same structure, and are both provided with a conductive area, a non-conductive area and a wiring hole. The conductive area is connected by plating a conductive material at the wiring hole position; wherein the wiring holes of the flexible printed circuit board include an A-phase wiring hole, a B-phase wiring hole and a ground wiring hole.

6. The electrical excitation method of the stator assembly of the traveling wave ultrasonic motor based on the multi-partitioned piezoelectric bimorph according to any one of claims 1 to 5, characterized in that: When the two sides of the flexible printed circuit board are respectively attached to the front surface of the first piezoelectric ceramic sheet and the front surface of the second piezoelectric ceramic sheet, the A phase of the first piezoelectric ceramic sheet is arranged opposite to the B phase of the second piezoelectric ceramic sheet, and the B phase of the first piezoelectric ceramic sheet and the A phase of the second piezoelectric ceramic sheet are arranged opposite to each other, and the polarization directions of the A phase of the first piezoelectric ceramic sheet and the B phase of the second piezoelectric ceramic sheet are set opposite to each other, and the polarization directions of the B phase of the first piezoelectric ceramic sheet and the A phase of the second piezoelectric ceramic sheet are set opposite to each other; The multi-partitioned piezoelectric dual chip adopts the d31 working mode to excite the corresponding working mode.

7. The electrical excitation method of the stator assembly of the traveling wave ultrasonic motor based on the multi-partitioned piezoelectric bimorph according to claim 6 is characterized by: Specifically, the excitation method is to connect the ground wire connection hole of the flexible printed circuit board separately, divide the electrical signal into two phases, apply a sin(ωt) signal to the A-phase connection hole of the flexible printed circuit board, and apply a sin(ωt+π / 2) signal to the B-phase connection hole of the flexible printed circuit board. At this time, the two-phase signals differ by π / 2; when the two-phase signals differ by -π / 2, the rotation direction of the motor changes.

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