KR101478710B1 - Ultrasonic motor - Google Patents

Abstract

According to the present invention, there is provided an ultrasonic motor including a stator, wherein the stator includes: an elastic body including an outer side surface and an inner side surface; And a piezoelectric body fixed to the outer surface of the elastic body, wherein the outer surface of the elastic body is continuously connected with the 16 surfaces maintained at a predetermined angle, and the inner surface of the elastic body is continuous The rotor and the elastic body can be brought into contact with each other on the sixteen surfaces by connecting the inner surface of the elastic body continuously while maintaining the sixteen surfaces at a certain angle, So that the performance of the ultrasonic motor can be improved.

Description

Ultrasonic motor {ULTRASONIC MOTOR}

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an ultrasonic motor, and more particularly, to an ultrasonic motor capable of increasing a contact surface between a stator and a rotor to improve performance.

In recent years, the rapid development of the information society has led to the need for faster and more precise electronic and optical devices. In particular, the marketability of portable mobile application products has been greatly expanded every year, reflecting consumer interest.

Cell phones equipped with dual cameras tend to adopt the functions of digital cameras such as auto focus and optical zoom as the number of pixels of the sensor increases, and related industries are focusing on development to competitively develop the market.

Stepping motors, VCMs, and piezoelectric ultrasonic motors are typical examples of driving devices for such high-resolution cell phone camera modules.

The piezoelectric ultrasonic motor enables simple vibration such as shrinkage and expansion generated when electricity is applied to the piezoelectric ceramics to be converted into circular or linear motion by friction between the stator and the rotor (or the mover) , High energy density, quick response speed, high position accuracy and off-power holding function as compared with the electromagnetic driving motor, and also there is no noise during operation and no influence of electromagnetic waves.

That is, the stator includes an elastic body and a piezoelectric body fixed to the elastic body, and the ultrasonic motor using the vibration of the piezoelectric body.

Since the piezoelectric body has a perovskite structure, it generates mechanical vibration in accordance with the electrical input of the element itself. The vibration generated in the piezoelectric body is enlarged through the elastic body, and the friction force generated between the stator and the rotor is converted into rotational force and used as an ultrasonic motor.

In the case of such an ultrasonic motor, when an electric input having a specific frequency is applied according to the structure of the motor, resonance occurs and the vibration of the motor increases. At this time, the electric input applied is an AC power having the frequency of the ultrasonic region band , The resonance frequency of the motor can also be determined by the size and thickness of the piezoelectric body used, the shape and the material of the motor.

In this case, as described above, the ultrasonic motor enables the simple vibration generated when electricity is applied to the piezoelectric body to function as a rotary motor by changing the circular or linear motion by friction between the stator and the rotor, It is important to increase the contact surface between the stator and the rotor for transmitting the vibration generated in the stator to the rotor.

Korean Patent Laid-Open No. 10-2012-105944

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ultrasonic motor capable of increasing the contact surface between a stator and a rotor for transmitting vibration generated in a stator to a rotor to improve performance.

The objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned can be clearly understood by those skilled in the art from the following description.

According to an aspect of the present invention, there is provided an ultrasonic motor including a stator, the stator including: an elastic body including an outer surface and an inner surface; And a piezoelectric body fixed to the outer surface of the elastic body, wherein the outer surface of the elastic body is continuously connected with the 16 surfaces maintained at a predetermined angle, and the inner surface of the elastic body is continuous And an ultrasonic motor connected to the ultrasonic motor.

The present invention is characterized in that the piezoelectric body is disposed on the 2n-1 surface (where n is 1, 2, 3, 4, 5, 6, 7, 8) of the outer surface, Wherein n is 1, 2, 3, 4, 5, 6, 7, 8, respectively.

Further, the present invention is characterized in that the piezoelectric body includes a first piezoelectric substance having a polarization in a first direction and a second piezoelectric substance having a polarization in a second direction, and the first piezoelectric substance and the second piezoelectric substance are located adjacent to each other And an ultrasonic motor.

Further, the present invention is characterized in that the first piezoelectric member includes a first piezoelectric member located on a first surface of the outer surface, a first piezoelectric member positioned on a fifth surface of the outer surface, And a first to fourth piezoelectric body located on a thirteenth surface of the outer surface.

Further, in the present invention, it is preferable that the second piezoelectric body includes a 2-1 piezoelectric body located on the third surface of the outer surface, a 2-2 piezoelectric body located on the seventh surface of the outer surface, And a second 2-4 piezoelectric element disposed on a 15th surface of the outer surface.

Further, the present invention is characterized in that the first 1-1 piezoelectric body and the second -1 piezoelectric body, which are located adjacent to each other, constitute a first piezoelectric substance group, and the 1-2 volt piezoelectric body and the 2-2 piezoelectric body, The first to eighth piezoelectric bodies and the second to eighth piezoelectric bodies forming the second piezoelectric substance group, which are adjacent to each other, constitute a third piezoelectric substance group, and the first to fourth piezoelectric bodies and the second to A power source having the same phase difference is supplied to the first and second piezoelectric bodies of the first, second and third piezoelectric substance groups, the third and fourth piezoelectric substance groups, and the piezoelectric substance forms the fourth piezoelectric substance group Thereby providing an ultrasonic motor.

Further, the present invention further includes a rotor positioned inside the elastic body, wherein the rotor contacts the inner surface of the elastic body when vibration occurs on the inner surface of the elastic body, and the rotor contacts the sixteen surfaces And an ultrasonic motor.

According to the present invention as described above, since the inner surface of the elastic body is continuously connected to the sixteen surfaces while maintaining a certain angle, the rotor and the elastic body can contact each other at 16 surfaces, So that the performance of the ultrasonic motor can be improved.

In the present invention, the piezoelectric body having the polarization in the first direction and the second direction, i.e., mutually opposite directions is fixed to one elastic body, the piezoelectric body having the polarization in the first direction is driven, or the piezoelectric body having the polarization in the second direction It is possible to realize a zoom-in or zoom-in function without having a separate mechanical mechanism.

1 is a perspective view showing a stator of an ultrasonic motor according to the present invention.
2 is a plan view showing a stator of an ultrasonic motor according to the present invention.
3 is a schematic plan view showing an ultrasonic motor including a stator according to the present invention.
FIG. 4A is a schematic view illustrating driving of a rotor according to an embodiment of the present invention, and FIG. 4B is a schematic view illustrating a method of applying power to a piezoelectric body according to an embodiment of the present invention.
FIG. 5A is a schematic view illustrating driving of a rotor according to another example of the present invention, and FIG. 5B is a schematic view illustrating a method of applying power to a piezoelectric body according to another example of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. &Quot; and / or "include each and every combination of one or more of the mentioned items. ≪ RTI ID = 0.0 >

Although the first, second, etc. are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used only to distinguish one component from another. Therefore, it goes without saying that the first component mentioned below may be the second component within the technical scope of the present invention.

The terminology used herein is for the purpose of illustrating embodiments and is not intended to be limiting of the present invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. The terms " comprises "and / or" comprising "used in the specification do not exclude the presence or addition of one or more other elements in addition to the stated element.

Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

The terms spatially relative, "below", "beneath", "lower", "above", "upper" And can be used to easily describe a correlation between an element and other elements. Spatially relative terms should be understood in terms of the directions shown in the drawings, including the different directions of components at the time of use or operation. For example, when inverting an element shown in the figures, an element described as "below" or "beneath" of another element may be placed "above" another element . Thus, the exemplary term "below" can include both downward and upward directions. The components can also be oriented in different directions, so that spatially relative terms can be interpreted according to orientation.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view showing a stator of an ultrasonic motor according to the present invention, and FIG. 2 is a plan view showing a stator of an ultrasonic motor according to the present invention.

1 and 2, a stator 100 of an ultrasonic motor according to the present invention includes an elastic body 110 including an outer side surface 110a and an inner side surface 110b, and an outer side surface 110a of the elastic body. And includes fixed piezoelectric bodies 121, 122, 131, 132.

The outer surface 110a of the elastic body 110 is continuously connected to the outer surface 110a of the elastic body 110 while maintaining a constant angle with respect to the outer surface 110a of the elastic body 110. In this case, And the inner surface 110b of the elastic body 110 is continuously connected to the sixteen surfaces while maintaining a certain angle.

For convenience of explanation, the 16 faces of the outer surface 110a of the elastic body 110 are referred to as 2n-1 faces (where n is 1, 2, 3, 4, 5, 6, 7 and 8) 2n-1 plane is defined as an odd-numbered plane among the 16 planes, and the 2n-1 plane is defined as an odd- And the 2n-plane corresponds to the plane located at the even-numbered of the 16 planes.

Therefore, in the present invention, the outer surface 110a of the elastic body 110 has a 2n-1 surface (where n is 1, 2, 3, 4, 5, 6, 7, 8) 1, 2, 3, 4, 5, 6, 7, 8).

The piezoelectric bodies 121, 122, 131, and 132 are disposed on eight surfaces of the sixteen surfaces of the outer surface 110a of the elastic body. More specifically, the piezoelectric bodies 121, 122, 131, 122, 131, and 132, respectively, of the outer surface 110a of the outer surface 110a (n is 1, 2, 3, 4, 5, 6, 7, 2, 3, 4, 5, 6, 7, 8) of the outer surface 110a, respectively.

Hereinafter, the piezoelectric bodies 121, 122, 131 and 132 are located on the 2n-1 surface (where n is 1, 2, 3, 4, 5, 6, 7 and 8) of the outer surface 110a The piezoelectric bodies 121, 122, 131 and 132 are formed on the 2n surface of the outer surface 110a (n is 1, 2, 3, 4, 5, 6, 7 and 8, respectively.

1 and 2, the piezoelectric bodies 121, 122, 131 and 132 include a first piezoelectric substance having a polarization in a first direction and a second piezoelectric substance having a polarization in a second direction, And the first piezoelectric body and the second piezoelectric body are located adjacent to each other.

More specifically, the first piezoelectric body includes a first piezoelectric body 121a located on a first surface of the outer surface 110a, a first piezoelectric body 121a located on a fifth surface of the outer surface 110a, A first 1-3 piezoelectric body 122a located on the ninth surface of the outer surface 110a and a 1-4th piezoelectric body 132a located on the 13th surface of the outer surface 110a.

The second piezoelectric body includes a 2-1 piezoelectric body 121b located on a third surface of the outer surface 110a, a 2-2 piezoelectric body 131b located on a seventh surface of the outer surface 110a, A second 2-3 piezoelectric body 122b located on the eleventh surface of the outer surface 110a and a second 2-4 piezoelectric body 132b located on the 15th surface of the outer surface 110a.

1 and 2, the first piezoelectric substance and the second piezoelectric substance adjacent to each other constitute one piezoelectric substance group, and the first piezoelectric substance and the second piezoelectric substance of the one piezoelectric substance group have a phase difference of The same power is supplied.

More specifically, the 1-1 piezoelectric member 121a and the 2-1 piezoelectric member 121b located adjacent to each other constitute the first piezoelectric substance group, and the 1-2 piezoelectric member 131a and the 2 nd piezoelectric member -2 piezoelectric bodies 131b constitute the second piezoelectric substance group and the first to third piezoelectric bodies 122a and 122b located adjacent to each other constitute the third piezoelectric substance group, The first to fourth piezoelectric bodies 132a and 132b constitute a fourth piezoelectric body group and the first piezoelectric body and the second piezoelectric body of the first piezoelectric body group, the second piezoelectric body group, the third piezoelectric body group and the fourth piezoelectric body group, respectively, 2 piezoelectric body is supplied with a power supply having the same phase difference.

At this time, in the present invention, a power source having a phase difference of 90 degrees is supplied between adjacent piezoelectric substrates.

That is, the AC power of the sin signal can be applied to the first piezoelectric substance group, the AC power of the cos signal can be applied to the second piezoelectric substance group positioned adjacent to the first piezoelectric substance group, The AC power of the sin signal can be applied to the third piezoelectric layer group positioned and the AC power of the cos signal can be applied to the fourth piezoelectric layer group positioned adjacent to the third piezoelectric layer group.

The elastic body 110 may be formed of a metal such as iron, stainless steel, brass, or aluminum. The piezoelectric body may be formed of a ceramic material such as alumina or zirconia. However, in the present invention, The material of the piezoelectric body is not limited.

Further, although not shown in the drawing, the ultrasonic motor according to the present invention may further include a power supply means for supplying a voltage to the piezoelectric body, and the piezoelectric body further includes an electrode for receiving power from the power supply means can do.

At this time, the power source applied from the power supply means can be a sinusoidal file. In case of a sinusoidal wave, the sinusoidal sin signal having a signal with an audible frequency of 20 kHz or more and the sinusoidal cos signal have a phase difference of 90 degrees and can be applied to the piezoelectric body.

The magnitude of the vibration generated through the elastic body is very small in micrometers and can generate vibration of more than 20,000 times per second through a signal having an audible frequency of 20 kHz or more. However, the magnitude of the displacement may vary depending on the size of the elastic body and the piezoelectric body, and may also vary depending on the applied power source and frequency.

3 is a schematic plan view showing an ultrasonic motor including a stator according to the present invention.

3, the ultrasonic motor according to the present invention includes a stator and a rotor 200. As described above, the stator includes an elastic body 110 including an outer surface 110a and an inner surface 110b, And piezoelectric bodies 121, 122, 131 and 132 fixed to the outer surface 110a of the elastic body.

At this time, the inner surface 110b of the elastic body 110 is continuously connected to the sixteen surfaces while maintaining a certain angle.

The rotor 200 is located on the inner side of the elastic body and contacts the inner side surface 110b of the elastic body 110 when vibration occurs on the inner side of the elastic body, .

At this time, the rotor 200 is formed in a cylindrical shape.

When the rotor 200 contacts the inner surface 110b of the elastic body 110, the inner surface 110b of the elastic body 110 is continuously connected to the inner surface 110b, When the vibration occurs on the inner surface of the elastic body, the rotor can contact the sixteen surfaces (see area A).

Meanwhile, as described above, it is important that the ultrasonic motor increases the magnitude of vibration generated in the stator, and increases the contact surface between the stator and the rotor for transmitting the vibration generated in the stator to the rotor.

In the present invention, since the inner surface of the elastic body is continuously connected with the sixteen surfaces being maintained at a constant angle, the rotor and the elastic body can contact each other on the sixteen surfaces, so that the contact surface between the stator and the rotor is increased, Performance can be improved.

FIG. 4A is a schematic view illustrating driving of a rotor according to an embodiment of the present invention, and FIG. 4B is a schematic view illustrating a method of applying power to a piezoelectric body according to an embodiment of the present invention.

4A and 4B, the piezoelectric bodies 121, 122, 131, and 132 according to the present invention include a first piezoelectric body having a polarization in a first direction and a second piezoelectric body having a polarization in a second direction, And the first piezoelectric body and the second piezoelectric body are positioned adjacent to each other. At this time, the first direction and the second direction may be opposite directions.

More specifically, the first piezoelectric body includes a first piezoelectric body 121a located on a first surface of the outer surface 110a, a first piezoelectric body 121a located on a fifth surface of the outer surface 110a, A first 1-3 piezoelectric body 122a located on the ninth surface of the outer surface 110a and a 1-4th piezoelectric body 132a located on the 13th surface of the outer surface 110a, The first 1-1 piezoelectric body 121a, the 1-2nd piezoelectric body 131a, the 1-3nd piezoelectric body 122a, and the 1-4th piezoelectric body 132a are arranged in a first direction (arrow direction in FIG. 4B) Lt; / RTI >

The driving of the rotor according to an embodiment of the present invention is performed by driving the first 1-1 piezoelectric member 121a, the 1-2nd piezoelectric member 131a, the 1-3th piezoelectric member 122a, And supplies power to the first to fourth piezoelectric bodies 132a.

At this time, the sine waveform AC power can be supplied to the 1-1 piezoelectric body 121a and the 1-3 piezoelectric body 122a, and the 1-2 volt body 131a and the 1-4 volt body The AC power of the cosine waveform may be supplied to the coil 132a.

When the elastic body with the piezoelectric body fixed thereon is viewed directly, bending vibration occurs in the bar of the elastic body through the polarization direction in Fig. 4B and the 90 degree phase difference power source. The generated bending vibration is transmitted to the inner surface of the elastic body, and the transmitted vibration can exhibit an elliptical displacement.

The generated vibration is transmitted to the rotor contacted with the inner surface of the elastic body, whereby the rotor can be rotated or moved.

At this time, the direction of displacement of the ellipse at the inner surface of the elastic body has the same direction, and the rotor in contact therewith also has the same direction.

The driving of the rotor according to an embodiment of the present invention as described above is performed by driving the first 1-1 piezoelectric member 121a, the 1-2nd piezoelectric member 131a, By supplying power to the 1-3 piezoelectric member 122a and the 1-4 piezoelectric member 132a, the rotor can be rotated or the rotor can be moved in the direction of the arrow in FIG. 4A.

That is, when the ultrasonic motor according to the present invention is used in a camera, if the lens 300 is fixed to the inside of the rotor 200 and the rotor is driven in a manner according to an embodiment of the present invention, Out function.

FIG. 5A is a schematic view illustrating driving of a rotor according to another example of the present invention, and FIG. 5B is a schematic view illustrating a method of applying power to a piezoelectric body according to another example of the present invention.

5A and 5B, the piezoelectric bodies 121, 122, 131, and 132 according to the present invention include a first piezoelectric body having a polarization in a first direction and a second piezoelectric body having a polarization in a second direction, And the first piezoelectric body and the second piezoelectric body are positioned adjacent to each other. At this time, the first direction and the second direction may be opposite directions.

More specifically, the second piezoelectric body includes a 2-1 piezoelectric body 121b located on a third surface of the outer surface 110a, a second piezoelectric body 121b disposed on a seventh surface of the outer surface 110a, A second 2-3 piezoelectric body 122b located on an eleventh surface of the outer surface 110a and a second 2-4 piezoelectric body 132b located on a 15th surface of the outer surface 110a, The second -1 piezoelectric body 121b, the second -2 piezoelectric body 131b, the 2-3nd piezoelectric body 122b, and the 2-4 piezoelectric body 132b are arranged in a second direction (arrow direction in FIG. 5B) Lt; / RTI >

The driving of the rotor according to another example of the present invention is performed by driving the second-1 piezoelectric body 121b, the second-2 piezoelectric body 131b, the 2-3nd piezoelectric body 122b, And supplies power to the 2-4 piezoelectric body 132b.

At this time, an AC power source of a sinusoidal waveform may be supplied to the 2-1 piezoelectric body 121b and the 2-3 piezoelectric body 122b, and the 2-2 piezoelectric body 131b and the 2- The AC power source of the cosine waveform may be supplied to the power source 132b.

When the elastic body to which the piezoelectric body is fixed is viewed in a straight line, bending vibration occurs in the bar of the elastic body through the polarization direction in Fig. 5B and the 90 degree phase difference power source. The generated bending vibration is transmitted to the inner surface of the elastic body, and the transmitted vibration can exhibit an elliptical displacement.

The generated vibration is transmitted to the rotor contacted with the inner surface of the elastic body, whereby the rotor can be rotated or moved.

At this time, the direction of displacement of the ellipse at the inner surface of the elastic body has the same direction, and the rotor in contact therewith also has the same direction.

The driving of the rotor according to another example of the present invention as described above is performed by driving the second-1 piezoelectric element 121b, the second-2 piezoelectric element 131b, the second-1 piezoelectric element 131b, By supplying power to the 2-3 th piezoelectric body 122b and the 2-4 piezoelectric body 132b, the rotor can be rotated or the rotor can be moved in the direction of the arrow in Fig. 5A.

That is, when the ultrasonic motor according to the present invention is used in a camera, if the lens 300 is fixed inside the rotor 200 and the rotor is driven in a manner according to another example of the present invention, for example, The zoom-in function can be realized.

Therefore, in the present invention, a piezoelectric body having a polarization in the first direction and the second direction, that is, mutually opposite directions, is fixed to one elastic body, and the piezoelectric body having the polarization in the first direction is driven, It is possible to realize a zoom-out function or a zoom-in function without having a separate mechanical mechanism.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

100: stator 110: elastic body
121a, 121b, 122a, 122b, 131a, 131b, 132a, 132b:
200: Rotor 300: Lens

Claims (8)

In an ultrasonic motor including a stator,
The stator includes: an elastic body including an outer side surface and an inner side surface; And a piezoelectric body fixed to an outer surface of the elastic body,
The elastic body has a hexagonal ring shape,
The outer surface of the elastic body has a 2n-1 surface (where n is 1, 2, 3, 4, 5, 6, 7 and 8) and 2n surfaces (where n is 1, 2, 3, 4, 5, 6 , 7, 8)
The piezoelectric body is disposed on the 2n-1 surface (where n is 1, 2, 3, 4, 5, 6, 7, 8) of the outer surface, or on the 2n surface , 2, 3, 4, 5, 6, 7, 8). delete delete The method according to claim 1,
Wherein the piezoelectric body includes a first piezoelectric substance having a polarization in a first direction and a second piezoelectric substance having a polarization in a second direction, and the first piezoelectric substance and the second piezoelectric substance are located adjacent to each other. 5. The method of claim 4,
Wherein the first piezoelectric body includes a first piezoelectric body located on a first surface of the outer surface, a first piezoelectric body located on a fifth surface of the outer surface, a first piezoelectric body located on a ninth surface of the outer surface, 3 piezoelectric element and a 1-4 piezoelectric element located on a 13th surface of the outer surface. 6. The method of claim 5,
Wherein the second piezoelectric body includes a second piezoelectric body located on a third surface of the outer surface, a second piezoelectric body positioned on a seventh surface of the outer surface, a second piezoelectric body positioned on the eleventh surface of the outer surface, 3 piezoelectric body, and a 2-4 piezoelectric body located on a fifteenth surface of the outer surface. The method according to claim 6,
The 1-1 piezoelectric member and the 2-1 piezoelectric member located adjacent to each other constitute a first piezoelectric substance group and the 1-2 piezoelectric substance and the 2-2 piezoelectric substance located adjacent to each other constitute a second piezoelectric substance group The first to third piezoelectric bodies and the second to eighth piezoelectric bodies which are adjacent to each other constitute a third piezoelectric substance group and the first to fourth piezoelectric bodies and the second to fourth piezoelectric bodies, Group,
And a power source having the same phase difference is supplied to the first piezoelectric substance and the second piezoelectric substance of each of the first piezoelectric substance group, the second piezoelectric substance group, the third piezoelectric substance group and the fourth piezoelectric substance group. The method according to claim 1,
And a rotor positioned inside the elastic body,
Wherein the rotor contacts the inner surface of the elastic body when vibration occurs on the inner surface of the elastic body.

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