JP2006314175A - Linear motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear motor in which displacement of the pressing direction vibration component and the traveling direction vibration component of a driving point can be controlled independently, and the need for degenerating resonance frequency of the pressing direction vibration component and the traveling direction vibration component of a driving point or for adjusting various dimensions can be eliminated. <P>SOLUTION: In the linear motor comprising a stator, a moving member arranged movably for the stator, and an ultrasonic motor located between the stator and the moving member and consisting of a vibrator applied with a piezoelectric material to one or both sides thereof or arranged such that the piezoelectric material itself functions as a vibrator and moving the moving member through ultrasonic vibration, the ultrasonic motor is arranged to utilize two orthogonal non-axisymmetric vibrations. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a linear motor configured to move a mover by an ultrasonic motor, and in particular, by pressing the ultrasonic motor so as to use two non-axisymmetric vibrations orthogonal to each other. It is possible to drive and control the component and the traveling direction vibration component independently, and to make it unnecessary to adjust various dimensions to reduce the resonance frequency of the pressing direction vibration and the traveling direction vibration. About.

The ultrasonic motor converts mechanical displacement and force obtained by using the inverse piezoelectric effect of the piezoelectric element into discrete or continuous rotation or linear motion. This will be described in detail with reference to FIG.
First, as shown in FIG. 8A, there is “(R, 1) -mode” that causes radial vibration. This is a pressing direction vibration component that is displaced in the direction of pressing the frictional contact surface. On the other hand, as shown in FIG. 8B, there is “((1, 1))-mode” that causes in-plane bending vibration. This is a traveling direction vibration component displaced in the traveling direction. Then, as shown in FIG. 8C, an elliptical locus is drawn at point A by the pressing direction vibration component and the traveling direction vibration component. A drive guide (not shown) is brought into contact therewith to convert it into rotation or linear motion.
A linear guide is configured to be converted into a linear motion by bringing the drive guide into contact therewith.

  For example, Patent Document 1 and Patent Document 2 disclose such ultrasonic motors.

JP 2000-60152 A JP 2002-218774 A

The conventional configuration has the following problems. That is, in the conventional ultrasonic motor, “(R, 1) -mode” shown in FIG. 8A and “((1,1))-mode” shown in FIG. There was a problem that the drive could not be controlled. That is, it is impossible to separately control the displacement of the pressing direction vibration component and the traveling direction component and the vibration speed at the driving point.
Further, it is necessary to degenerate the resonance frequencies of “(R, 1) -mode” shown in FIG. 8A and “((1, 1))-mode” shown in FIG. 8B. However, there is a problem that the ratio between the inner diameter and the outer diameter of the ring must be adjusted.

The present invention has been made based on such points, and the object of the present invention is to make it possible to separately control the displacement and vibration speed of the pressing direction vibration component and the traveling direction vibration component of the driving point. An object of the present invention is to provide a linear motor using an ultrasonic motor that can eliminate the need for adjustment of various dimensions for the purpose of reducing the resonance frequency of the pressing direction vibration and the traveling direction vibration.

In order to solve the above problems, a linear motor according to claim 1 of the present invention is provided between a stator, a mover installed to be movable with respect to the stator, and between the stator and the mover. A piezoelectric material is attached to both surfaces or one surface of a vibrating body, or the piezoelectric material itself is configured to function as a vibrating body, and includes an ultrasonic motor that moves the mover by ultrasonic vibration. In the linear motor formed as described above, the ultrasonic motor is configured to use two non-axisymmetric vibrations orthogonal to each other.
A linear motor according to claim 2 is the linear motor according to claim 1,
The electrode made of the piezoelectric material is divided into four in the circumferential direction.
According to a third aspect of the present invention, there is provided the linear motor according to the second aspect of the present invention, wherein the piezoelectric material is divided into four in the circumferential direction on each of both surfaces of the vibrating body having an annular shape and having T-shaped support portions at both left and right ends. It is characterized by being pasted.
According to a fourth aspect of the present invention, there is provided the linear motor according to the second aspect, wherein a piezoelectric material divided into four in the circumferential direction is attached to each of both surfaces of the annular vibrating body. .
According to a fifth aspect of the present invention, there is provided the linear motor according to the second aspect, wherein a piezoelectric material divided into four in the circumferential direction is attached to each of both surfaces of the disc-shaped vibrating body. It is.
A linear motor according to a sixth aspect of the present invention is the linear motor according to the second aspect of the present invention, characterized in that it is a dual power supply system.
According to a seventh aspect of the present invention, there is provided a linear motor according to the second aspect, wherein the linear motor is a four power supply system.

As described above, the linear motor according to the present invention includes a stator, a mover installed to be movable with respect to the stator, and installed between the stator and the mover. A linear motor comprising a piezoelectric material pasted on one side, or an ultrasonic motor configured to move the mover by ultrasonic vibration, wherein the piezoelectric material itself functions as a vibrator. Since the ultrasonic motor is configured to use two non-axisymmetric vibrations orthogonal to each other, the pressing direction vibration component and the traveling direction vibration component can be separately excited. In addition, since the same vibration mode orthogonal to each other is used, for example, the ratio of the inner diameter to the outer diameter of the ring must be adjusted in order to degenerate the resonance frequency of the pressing direction vibration and the traveling direction vibration. Complicated adjustment work can be eliminated.

Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing the configuration of a linear motor. First, there is a base 1 as a stator, and a slider 5 as a movable element is installed on the base 1 through cross roller guides 3 and 3 so as to be movable in a direction perpendicular to the paper surface.

The slider 5 is driven by an ultrasonic motor 7 installed on the base 1 side. The ultrasonic motor 7 is installed on the base 1 via a support base 9. A driving guide 11 is attached to the slider 5 side. Further, a pressure spring 13 is installed on the left side of the ultrasonic motor 7 in FIG. 1 via a support member 15, and the ultrasonic motor 7 is pressed against the drive guide 11 by the pressure spring. It has been. A friction material 17 is installed between the ultrasonic motor 7 and the driving guide 11.

The ultrasonic motor 7 is configured as shown in FIGS. First, there is an elastic body 21 as a vibrating body, and the elastic body 21 includes an annular portion 23 and support portions 25 and 27 provided at both left and right ends of the annular portion 23. The support portions 25 and 27 are “T-shaped”. A through hole 23 a is formed at the center of the annular portion 23.

Piezoelectric ceramics (for example, PZT) 31 as a piezoelectric material divided into four equal parts are respectively attached to the upper surface of the annular portion 23 of the elastic body 21. Further, piezoelectric ceramics 31 as piezoelectric materials divided into four equal parts are respectively attached to the lower surface of the annular portion 23 of the elastic body 21.
The piezoelectric material is not limited to piezoelectric ceramics, and may be a piezoelectric crystal material (for example, LiTaO ₃ ).

Further, the drive power system of the ultrasonic motor has a configuration as shown in FIG. 4 and adopts a so-called “two power system”. Also, “((1,1)) ′-mode” and “((1,1))-mode” are used, and the electrode to which sin ωt is applied is “(1,1) ′. −mode ”, and the electrode to which cos ωt is applied is“ ((1, 1))-mode ”, which is a component in the traveling direction. Thus, in this embodiment, the same orthogonal mode is used.

As described above, according to the present embodiment, the following effects can be obtained.
First, since it is configured to use two orthogonal non-axisymmetric vibrations, that is, “((1,1)) ′-mode” and “((1,1))-mode”, the ultrasonic wave It is now possible to separately excite the vibration component in the pressing direction that is displaced in the direction of pushing the frictional contact surface of the motor and the vibration component in the traveling direction that is displaced in the traveling direction of the ultrasonic motor.
The “((1,1)) ′-mode” and “((1,1))-mode” are the same mode, and are always in a degenerate condition regardless of the ratio of the inner diameter to the outer diameter of the ring. Therefore, it is not necessary to adjust the ratio between the inner diameter and the outer diameter of the elastic body 21.

Next, a second embodiment of the present invention will be described with reference to FIG. In the case of the second embodiment, the drive power supply system is different from that in the first embodiment. That is, as shown in FIG. 4, in the case of the second embodiment, a so-called “four power supply method” is adopted.
Other configurations are the same as those in the first embodiment, and a description thereof will be omitted.
And even if it is such a structure, there can exist an effect similar to the case of the said 1st Embodiment.

Next, a third embodiment of the present invention will be described with reference to FIG. In this case, an elastic body 41 having a shape different from that of the elastic body 21 in the case of the first embodiment is used. That is, the elastic body 41 in the third embodiment is not configured to have a support portion unlike the elastic body 21 in the first embodiment, and is formed only from an annular portion. It is what. A through hole 41a is formed at the center.
Other configurations are the same as those in the first embodiment, and the same portions are denoted by the same reference numerals and description thereof is omitted.
Even with such a configuration, the same effects as those of the first and second embodiments can be obtained.

Next, a fourth embodiment of the present invention will be described with reference to FIG. Also in this case, an elastic body 51 having a shape different from that of the elastic body 21 in the case of the first embodiment is used. That is, the elastic body 51 in the fourth embodiment is not configured to have a support portion unlike the elastic body 21 in the first embodiment, and is not a ring but a circular portion. It is formed only from.

The piezoelectric ceramic 61 is shaped like a circle divided into four equal parts.
Other configurations are the same as those in the first embodiment, and the same portions are denoted by the same reference numerals and description thereof is omitted.
Even with such a configuration, the same effects as those of the first and second embodiments can be obtained.

The present invention is not limited to the first to fourth embodiments.
The shape of the elastic body is not limited to that illustrated in the first to fourth embodiments, and various shapes are assumed. For example, an elastic body having a shape in which T-shaped support portions are continuously provided on both sides of the circular portion may be used.
In the first to fourth embodiments, the piezoelectric ceramic or piezoelectric crystal material is attached to the upper and lower surfaces of the elastic body. However, the present invention is not limited to this, and the elastic body is attached only to one surface. Such a configuration is also possible.
In the case of the first to fourth embodiments, the description has been given by taking as an example a configuration in which a piezoelectric material is attached to a vibrating body such as an elastic body. However, such a vibrating body is not used. In addition, the present invention can also be applied to a structure composed only of a piezoelectric material.

The present invention relates to a linear motor driven by an ultrasonic motor, and in particular, by configuring the ultrasonic motor to use two non-axisymmetric vibrations orthogonal to each other, a pressing direction vibration component and a traveling direction vibration component Can be controlled independently, and various dimensional adjustments for reducing the resonance frequency of the pressing direction vibration and the traveling direction vibration can be made unnecessary. It is.

It is a figure which shows the 1st Embodiment of this invention and is a cross-sectional view which shows the structure of a linear motor. It is a figure which shows the 1st Embodiment of this invention, and is a top view which shows the structure of a part of linear motor. FIG. 3A is a plan view showing the configuration of an ultrasonic motor, and FIG. 3B is a side view showing the configuration of the ultrasonic motor, showing the first embodiment of the present invention. It is a figure which shows the 1st Embodiment of this invention and is a top view which shows the drive power supply system of an ultrasonic motor. It is a figure which shows the 2nd Embodiment of this invention, and is a top view which shows the drive power supply system of an ultrasonic motor. FIG. 6A is a plan view showing the configuration of an ultrasonic motor, and FIG. 6B is a side view showing the configuration of the ultrasonic motor. FIG. 7A is a plan view showing the configuration of an ultrasonic motor, and FIG. 7B is a side view showing the configuration of the ultrasonic motor, showing a fourth embodiment of the present invention. FIG. 8A is a diagram illustrating a conventional example, FIG. 8A is a diagram illustrating a vibration component that is displaced in the direction of pushing the inner frictional contact surface of the driving principle of an ultrasonic motor, and FIG. FIG. 8C is a diagram showing a state in which a vibration component displaced in the direction of pushing the frictional contact surface and a vibration component displaced in the travel direction are combined.

Explanation of symbols

7 Ultrasonic motor 21 Elastic body 23 Annular part 25 Support part 27 Support part 31 Piezoelectric ceramics

Claims (7)

A stator,
A mover installed movably with respect to the stator;
It is installed between the stator and the mover, and a piezoelectric material is attached to both sides or one side of the vibrating body, or the piezoelectric material itself is configured to function as a vibrating body, and is vibrated ultrasonically. An ultrasonic motor for moving the mover;
In a linear motor comprising:
A linear motor characterized in that the ultrasonic motor is configured to use two non-axisymmetric vibrations orthogonal to each other. The linear motor according to claim 1,
A linear motor characterized in that the electrode made of the piezoelectric material is divided into four in the circumferential direction. The linear motor according to claim 2,
A linear motor characterized in that a piezoelectric material divided into four in the circumferential direction is attached to each of both surfaces of a vibrating body having an annular shape and having support portions at both left and right ends. The linear motor according to claim 2,
A linear motor characterized in that a piezoelectric material divided into four in the circumferential direction is attached to each of both surfaces of an annular vibrator. The linear motor according to claim 2,
A linear motor, wherein a piezoelectric material divided into four in the circumferential direction is attached to each of both surfaces of a disk-shaped vibrating body. The linear motor according to claim 2,
A linear motor characterized by a dual power supply system. The linear motor according to claim 2,
A linear motor characterized by a four power supply system.

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