A bending vibration mode inertial ultrasonic motor and its control method

Abstract

The present invention discloses a bending vibration type inertial ultrasonic motor and its control method, which relates to the technical field of ultrasonic motors. The bending vibration type inertial ultrasonic motor includes: a stator, a piezoelectric ceramic, a carbon fiber tube, a rod, a slider and a housing. The stator is a circular ring metal sheet, and there are uniformly distributed fixing structures along the outer edge of the circular ring, which are connected to the housing; the piezoelectric ceramic is a flat circular ring sheet, and one sheet is respectively attached to the upper and lower surfaces of the stator; the carbon fiber tube and the rod form a pair of friction pairs, converting the bending vibration of the stator into the up and down movement of the rod; the rod is fixedly connected to the slider and can drive the slider to move. The present invention can provide sufficient rotational speed output and torque output while ensuring the small size of the motor and meeting the structural requirements of the micro zoom system.

Description

Technical Field

[0001] The present invention relates to the technical field of ultrasonic motors, and particularly to a bending vibration type inertial ultrasonic motor. Background Art

[0002] The most typical application of ultrasonic motors in the civilian field is to drive camera lenses. Compared with traditional motors, ultrasonic motors have unique advantages in the field of miniaturization. Therefore, in the field of micro-zoom systems, ultrasonic motors have broad development space. A typical application of a micro-zoom system is the zoom lens of a mobile phone. Currently, the mainstream mobile phones on the market still achieve the zoom function through the combination of digital zoom and multiple lenses. However, digital zoom is based on sacrificing picture quality, which makes the performance of most mobile phone lenses during zooming unsatisfactory. While a micro-ultrasonic motor can be used as a platform for carrying lenses to achieve optical zoom on mobile phone lenses, thus greatly improving the imaging ability of mobile phone lenses. Summary of the Invention

[0003] Aiming at the above technical problems, the present invention aims to provide a bending vibration type inertial ultrasonic motor, which can meet the requirements of micro-zoom systems and has various advantages of general ultrasonic motors, such as fast response, low noise, no electromagnetic interference, etc.

[0004] To achieve the above object, the embodiments of the present invention adopt the following technical solutions:

[0005] The bending vibration type ultrasonic motor of the embodiment of the present invention includes: a stator 1, a piezoelectric ceramic 2, a carbon fiber tube 3, a rod 4, a slider 5, and a housing 6. The stator 1 is fixed to the boss on the inner side of the housing 6 through the fixing structures uniformly distributed on its edge; the piezoelectric ceramic 2 is a flat circular ring, and the upper and lower pieces are respectively pasted on the annular surface of the stator 1. The polarization directions of the piezoelectric ceramics 2 should be the same, either all upward or all downward; the carbon fiber tube 3 should be fixed on the upper surface of the upper piezoelectric ceramic 2, and the fixing position should be on the nodal circle of the bending vibration mode excited by the stator, and the two carbon fiber tubes 2 should be symmetrically distributed on a diameter of the piezoelectric ceramic 2 ring; the friction pair 7 should have an appropriate pre-pressure, which can be achieved by the cooperation of carbon fiber tubes 3 and rods 4 with different sizes, or other methods can also be used; both ends of the slider 5 have fixed structures with holes and are connected to one end of the rod 4. Through the friction pair 7, using the inertia principle and the "slow in and fast out" principle, the bending vibration of the stator 1 can be converted into the one-way movement of the slider 5.

[0006] As an implementation manner, there are several fixing structures 8 on the outer ring of the stator 1, which are evenly distributed on the outer ring of the stator 1.

[0007] As an implementation manner, the stator 1 is made of a material with low density and high strength, such as aluminum alloy, etc.

[0008] As an implementation manner, the inner diameter dimension of the piezoelectric ceramic 2 is the same as that of the stator 1. In terms of the outer diameter, it is required that the outer diameter of the stator is greater than or equal to the outer diameter of the piezoelectric ceramic. The upper and lower piezoelectric ceramics are both polarized along the thickness direction, and the polarization directions are the same.

[0009] As an implementation manner, the friction pair 7 needs to have an appropriate pre-pressure, which can be achieved by the cooperation of carbon fiber tubes 3 and rods 4 with different sizes, or can also be achieved by other methods.

[0010] As an implementation manner, the slider 5 is made of a light material.

[0011] As an implementation manner, when the ultrasonic motor is in the working state, at this time, the polarization directions of the upper and lower piezoelectric ceramics are the same. A square wave or sawtooth wave signal is applied to the upper and lower surfaces of the upper and lower piezoelectric ceramics 2 through the electrodes to excite the stator 1 to generate out-of-plane bending vibration.

[0012] The bending vibration type inertial ultrasonic motor provided by the embodiment of the present invention can provide sufficient output torque and output speed while ensuring a small structure, and also maintains the consistent advantages of ultrasonic motors, such as compact structure, fast response, low noise, and immunity to electromagnetic interference, etc. It can be applied to micro zoom systems and optical zoom lenses of mobile phones, etc. The embodiments of the present invention have broad application prospects in the fields of optical instruments, micro machinery, aerospace, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description 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.

[0014] Figure 1 It is a schematic structural diagram of a bending vibration type inertial ultrasonic motor provided by an embodiment of the present invention;

[0015] Figure 2 It is a schematic structural diagram of a stator of a bending vibration type inertial ultrasonic motor provided by an embodiment of the present invention;

[0016] Figure 3 It is a schematic structural diagram of a friction pair of a bending vibration type inertial ultrasonic motor provided by an embodiment of the present invention;

[0017] Figure 4 It is a schematic working diagram of a bending vibration type inertial ultrasonic motor provided by an embodiment of the present invention;

[0018] Figure 5 It is a schematic diagram of an excitation signal of a bending vibration type inertial ultrasonic motor provided by an embodiment of the present invention;

[0019] In the figure, 1 - stator, 2 - piezoelectric ceramic, 3 - carbon fiber tube, 4 - rod, 5 - slider, 6 - housing, 7 - friction pair, 8 - fixing structure, 9 - upper and lower surfaces of the stator. Specific embodiments

[0020] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. The embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present invention and should not be construed as limiting the present invention.

[0021] Those skilled in the art of the present technology can understand that, unless otherwise defined, all terms used herein, including technical terms and scientific terms, have the same meaning as the general understanding of those of ordinary skill in the art to which the present invention pertains. It should also be understood that terms such as those defined in a general dictionary should be understood to have a meaning consistent with the meaning in the context of the prior art, and will not be interpreted in an idealized or overly formal sense unless defined as here.

[0022] The embodiments of the present invention provide a bending vibration type inertial ultrasonic motor, which can improve the performance of the motor while ensuring a small structure, and has the common advantages of ultrasonic motors, such as compact structure, fast response, low noise, and immunity to electromagnetic interference.

[0023] To achieve the above object, the embodiments of the present invention adopt the following technical solutions:

[0024] The embodiments of the present invention provide a bending vibration type inertial ultrasonic motor, such as Figure 1As shown in the figure, it includes: a stator 1, a piezoelectric ceramic 2, a carbon fiber tube 3, a rod 4, a slider 5, and a housing 6. It is characterized in that: the stator 1 is evenly distributed on the convex platform inside the housing 6 through the fixing structures evenly distributed on its edge; the piezoelectric ceramic 2 is a flat circular ring plate, and the upper and lower two pieces are respectively pasted on the annular surface of the stator 1. The polarization directions of the piezoelectric ceramics 2 should be the same, both upward or downward; the carbon fiber tube 3 should be fixed on the upper surface of the upper piezoelectric ceramic 2, and the fixed position should be on the nodal circle of the bending vibration mode excited by the stator, and the two carbon fiber tubes 2 should be symmetrically distributed on a diameter of the piezoelectric ceramic 2 ring; the friction pair 7 should have an appropriate pre-pressure, which can be achieved by the cooperation of carbon fiber tubes 3 and rods 4 with different sizes, or other methods can also be used; both ends of the slider 5 have fixed structures with holes and are connected to one end of the rod 4. Through the friction pair 7, using the inertia principle, the one-way displacement of the rod 4 in the carbon fiber tube 3 can be accumulated with the number of vibrations, and thus the bending vibration of the stator 1 can be converted into the one-way movement of the slider 5. Using the inertia principle and the "slow in and fast out" principle, the bending vibration of the stator 1 can be converted into the one-way movement of the slider 5.

[0025] As an implementation manner, the position where the carbon fiber tube 3 is fixed on the side of the piezoelectric ceramic 2 needs to be determined with reference to the nodal circle of the working mode of the stator 1. In this example, the working mode selected is the out-of-plane second-order bending vibration. Therefore, the carbon fiber tube 3 is fixed on a symmetry line of the fixing structure on the ring edge of the stator 1.

[0026] As an implementation manner, the friction pair 7 is composed of the cooperation of the carbon fiber tube 3 and the rod 4, and there should be an appropriate pre-pressure between the carbon fiber tube 3 and the rod 4. In this example, different specifications of the carbon fiber tube 3 and the rod 4 are selected for cooperation to achieve the purpose of adjusting the pre-pressure. Finally, a rod 4 with an outer diameter of 0.3 mm and a carbon fiber tube 3 with an inner diameter of 0.3 mm are selected, and a relatively ideal working state can be obtained.

[0027] As an implementation manner, there are other ways to apply the pre-pressure of the friction pair 7. For example, the side of the carbon fiber tube 3 is cut open, and then an elastic restraint is tied outside the carbon fiber tube 3. By adjusting the stiffness of the elastic restraint, the adjustment of the pre-pressure of the friction pair 7 can be achieved.

[0028] As an implementation manner, the inner diameter size of the piezoelectric ceramic 2 is the same as the inner diameter size of the stator 1. In terms of the outer diameter, the outer diameter size of the stator 1 is greater than or equal to the outer diameter size of the piezoelectric ceramic 2. The upper and lower two piezoelectric ceramics are polarized along the thickness direction, and the polarization directions are the same.

[0029] In the embodiment of the present invention, the polarization directions of the upper and lower piezoelectric ceramics are the same. A square wave signal or a sawtooth wave signal is applied to the upper and lower piezoelectric ceramics 2 respectively through electrodes to excite the stator 1 to generate out-of-plane bending vibration. In this example, it is the second-order out-of-plane bending vibration, and then the bending vibration is transmitted to the movement of the slider 5 through the friction pair 7.

[0030] In the embodiment of the present invention, when the motor is running, the working process is as Figure 4 shown. The working principle is as follows: Under the action of the excitation voltage as shown in Figure 5 when the stator 1 is excited to generate the second-order out-of-plane bending vibration, it drives the carbon fiber tube 3 at the nodal circle position to vibrate up and down, thereby driving the slider 5 to move up and down. When the excitation voltage slowly changes from a to b, the rod 4 moves smoothly upward together with the carbon fiber tube 3 under the action of static friction; when the excitation voltage suddenly drops rapidly from b to c, the carbon fiber tube 3 moves rapidly downward. Due to the inertial force of the rod overcoming the sliding friction, it does not move downward with the carbon fiber tube 3, so the rod 4 moves upward by one step. When the excitation voltage slowly changes from c to d again, the rod 4 moves upward with the carbon fiber tube 3 again; when the voltage drops suddenly from d to e, the carbon fiber tube 3 moves rapidly downward. Due to the inertial force of the rod 4, it does not move downward with the carbon fiber tube 3 either, so the rod 4 moves upward by one step again. In this way, it repeats continuously and accumulates gradually, so as to realize the continuous step-by-step movement of the rod 4 upward along the carbon fiber tube 3, thereby driving the slider 5 to move in the same direction. Similarly, when an anti-phase excitation signal is applied, the rod 4 can realize continuous movement downward along the carbon fiber tube 3.

[0031] In the embodiment of the present invention, the slider 5 is a hollow ring structure, and there are also circular holes at the bottom of the outer shell 6, so that light can conveniently pass through the motor. The structure of the slider 5 can also be changed according to actual requirements.

[0032] In the embodiment of the present invention, there are 4 fixing structures 8 on the outer ring of the stator 1, which are evenly distributed on the outer ring of the stator 1, as Figure 2 shown.

[0033] In the embodiment of the present invention, the stator 1 is made of aluminum alloy 6061, and the upper and lower surfaces 9 are ground. Of course, the manufacturing material of the stator 1 can also be replaced with other light materials.

[0034] In the embodiment of the present invention, the slider 5 is made of aluminum alloy 6061, and it can also be made of other light materials.

[0035] In the example of the present invention, in order to increase the bending vibration amplitude of the stator 1, the second-order bending vibration mode is selected.

[0036] A bending vibration type inertial ultrasonic motor provided by an embodiment of the present invention has good performance at both the output torque end and the output speed end while meeting the requirement of a small structure, and also has the advantages of general ultrasonic motors, such as compact structure, fast response, low noise, and immunity to electromagnetic interference, etc. It can be applied to a micro zoom system and an optical zoom lens of a mobile phone, etc. The embodiment of the present invention has broad application prospects in the fields of optical instruments, micro machinery, aerospace, etc.

[0037] Each embodiment in this specification is described in a progressive manner. For the same or similar parts among the embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. In particular, for the device embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and for the relevant parts, reference can be made to the partial description of the method embodiments.

[0038] As described above, the above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A bending vibration type inertial ultrasonic motor, characterized in that: It includes a stator (1), a piezoelectric ceramic (2), a carbon fiber tube (3), a rod (4), a slider (5), and a housing (6); among which, The stator (1) is a circular ring piece, fixed on the inner side boss of the housing (6), and annular piezoelectric ceramics (2) are fixed on both sides of the stator (1); on one side of the stator (1), the carbon fiber tube (3) is fixed on the piezoelectric ceramic (2); the rod (4) and the carbon fiber tube (3) form a friction pair, and the displacement generated by the bending vibration of the stator (1) is transmitted through this friction pair, thereby pushing the slider (5) to move, and the other end of the rod (4) is fixed on both sides of the slider (5); The inner diameter size of the piezoelectric ceramic is the same as the inner diameter size of the stator, and in terms of the outer diameter, the outer diameter size of the stator (1) is greater than or equal to the outer diameter size of the piezoelectric ceramic (2). The upper and lower piezoelectric ceramics are polarized along the thickness direction, and the polarization directions are the same; the position where the carbon fiber tube (4) is fixed on the side of the piezoelectric ceramic (2) is determined with reference to the nodal circle of the working mode of the stator.

2. The bending vibration type inertial ultrasonic motor according to claim 1, characterized in that: The stator (1) is a circular ring-shaped sheet structure, and there are uniformly distributed fixing structures on its circumferential outer edge.

3. The bending vibration type inertial ultrasonic motor according to claim 1, characterized in that: The piezoelectric ceramic (2) is provided with an annular structure matching the stator, and there are two piezoelectric ceramics (2) of the same specification in the ultrasonic motor, and the upper and lower two are respectively fixed on the upper and lower surfaces of the stator.

4. The bending vibration type inertial ultrasonic motor according to claim 1, characterized in that: One end of the carbon fiber tube (3) is fixed on one side surface of the piezoelectric ceramic (2), and the fixed position is determined by the nodal circle generated by the working mode of the selected piezoelectric ceramic.

5. The bending vibration type inertial ultrasonic motor according to claim 4, characterized in that: The carbon fiber tube (3) and the rod (4) form a set of friction pairs (7), and the friction pairs (7) convert the bending vibration of the stator (1) into the one-way movement of the slider (5) through the inertial action and the working principle of slow forward and fast backward.

6. The bending vibration type inertial ultrasonic motor according to claim 5, characterized in that: There is a pre-pressure between the carbon fiber tube (3) and the rod (4) in the friction pair (7), and by selecting carbon fiber tubes (3) with different inner diameters and rods (4) with different outer diameters, the pre-pressure that can drive the motor to operate is adjusted.

7. A control method for the bending vibration type inertial ultrasonic motor according to claim 1, characterized in that: When the ultrasonic motor is in the working state, at this time, the polarization directions of the upper and lower piezoelectric ceramics (2) are the same. The stator (1) is grounded through the electrode, and the same square wave or sawtooth wave signal is connected to the side surfaces of the two piezoelectric ceramics (2) that do not contact the stator (1), and the stator (1) is excited to generate bending vibration, and the one-way movement of the slider (5) can be realized.

8. The control method according to claim 7, characterized in that: The square wave or sawtooth wave signals are opposite, and the stator (1) is sufficiently excited to generate bending vibration, and the reverse movement of the slider (5) can be realized.

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