JP3053659B2 - Linear ultrasonic motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear ultrasonic motor for linearly driving a mover.

[0002]

2. Description of the Related Art A conventional linear ultrasonic motor is provided with a phase difference over substantially the entire back surface of an oval (elliptical) elastic substrate in which, for example, a semicircular portion and a long side portion are continuous. A plurality of piezoelectric elements are laminated, and the entire surface of the elastic body is excited by the piezoelectric elements. The ultrasonic traveling wave is applied to the slider from an elliptical vibration transmitting member formed integrally with the elastic body. There is something that is made to convey (Japanese Patent Laid-Open No. 61-351)
No. 77). Since the ultrasonic traveling wave circulates on the surface of the elliptical vibration transmitting member, the direction of the ultrasonic traveling wave is opposite between one long side portion of the vibration transmitting member and the long side portion opposed thereto. It is. Therefore, in the conventional linear type ultrasonic motor, the slider is brought into contact with one long side of the vibration transmitting member to take out a linear driving force from one side of the two long sides,
Alternatively, two sliding elements are brought into contact with both long sides of the vibration transmitting member to take out linear driving forces in mutually different directions.

[0003]

As described above, in the conventional linear type ultrasonic motor, the linear driving force obtained from the two long sides of the vibration transmitting member is dispersed in two directions, ie, forward and reverse. There is a disadvantage that the linear driving force in the direction becomes weaker accordingly. Therefore, the conventional linear type ultrasonic motor is required to be compact in a small installation space, and cannot be used as a drive device such as a power window, a sunroof or a sunshade of an automobile which requires a strong linear driving force. There was a point. SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a linear ultrasonic motor which is compact and can obtain a strong linear driving force.

[0004]

In order to achieve the above object, according to the present invention, as illustrated in the drawings, there is provided an ultrasonic conduction passage 6 configured as a substantially oval or circular closed passage.
In ultrasonic linear type ultrasonic motor 1 so as to linearly drive the movable member 20 by ultrasonic traveling wave generated on the surface of the conductive passages 6, wherein in contact with the part of the surface of the ultrasonic transmission path 6 It is driven to rotate by ultrasonic traveling waves
At least one rotating roller 3 which is supported on sea urchin base 7
And a movable element 20 adapted to contact both the surface of the ultrasonic conduction path 6 on the side facing the rotary roller 3 and the rotary roller 3. An ultrasonic motor 1 is provided.

[0005]

In the linear type ultrasonic motor 1 configured as described above, the traveling ultrasonic wave circulates on the surface of the ultrasonic conduction path 6. Then, the rotating roller 3 is rotated by an ultrasonic traveling wave of a transverse wave bent up and down, and a linear driving force is transmitted to the mover 20 via the rotating roller 3. On the other hand, since the mover 20 is also in contact with the ultrasonic conduction path 6 facing the rotary roller 3, the mover 20 also receives a linear driving force from the ultrasonic conduction path 6. Although the ultrasonic traveling waves in the ultrasonic conduction path 6 provided with the rotating roller 3 and the ultrasonic conduction path 6 opposed thereto are in opposite directions, the provision of the rotating roller 3 in the ultrasonic conduction path 6 Since the linear driving force is reversed, the rotary roller 3 and the ultrasonic conduction path 6 facing the rotary roller 3
The two linear driving forces in the same direction act simultaneously on the mover 20 abutting on both.

[0006]

An embodiment of the present invention will be described with reference to the drawings. 1 is a perspective view showing a linear ultrasonic motor and a mover, FIG. 2 is a sectional view taken along line AA of FIG. 1, and FIG. 3 is a bottom view showing the linear ultrasonic motor separated from a base. The linear type ultrasonic motor 1 includes a stator 2 for generating a driving force,
And a rotating roller 3 for reversing the direction of action of the driving force.

The stator 2 is formed of an elastic body made of a copper alloy, and the semi-circular portions 4 and 4 'and the long sides 5 and 5' are continuous to form an oval closed ultrasonic passage. 6 and a substrate 8 at the center for fixing the linear ultrasonic motor 1 to the base 7, and the ultrasonic conduction path 6 and the substrate 8 are integrally formed.

The stator 2 is fastened and fixed to the base 7 by inserting a fixing bolt 10 into a long hole 9 in the center of the substrate 8. A bolt 11 from the base 7 is provided outside the long side 5 'on the right side of FIG. 2, and a bolt 11' is provided from the base 7 through a long hole 14 of the substrate 8 inside the long side 5 '. Are assembled, and the horizontal shaft 12 is fixed to the bolts 11 and 11 '. The rotating roller 3 is rotatably supported on the horizontal shaft 12, and the lower surface of the rotating roller 3 is configured to abut on the surface of the long side portion 5 ′ of the ultrasonic conduction path 6.

A large number of lateral grooves 1 are formed on the surface of the ultrasonic conduction passage 6.
3 are formed. As shown in FIG. 2, the cross section of the ultrasonic transmission path 6 below the bottom of the lateral groove has a rectangular shape. Two long holes 14 are formed in the substrate 8 adjacent to the long sides 5 and 5 'of the ultrasonic conduction path 6.
Therefore, the ultrasonic conduction passage 6 and the substrate 8 are connected to the semicircular portions 4, 4 '.
At the long sides 5, 5 '.
4 separated. The central portion of the substrate 8 is formed to be slightly thicker.

As shown in FIG. 3, three piezoelectric elements 15, 16 and 1 are provided on the bottom surfaces of the long sides 5 and 5 'of the ultrasonic conduction path 6.
7 is stuck. Each of the piezoelectric elements 15, 16, and 17 is provided with electrodes on both sides of a plate-shaped ceramic polarized material having a thickness of about 0.5 mm.
Each of 5 and 16 is polarized in the thickness direction such that the polarization direction alternates every ６ of the entire length. In the figure, the hatched portions are polarized portions, and the portions having different hatched directions have different polarization directions. The second piezoelectric element 16 is separated from the first piezoelectric element 15 by the ultrasonic conduction path 6.
Is fixed at a position where the position phase is shifted by ４ of the wavelength λ of the standing wave generated in the above. The third piezoelectric element 17 has a length of ４ of the wavelength λ, and
/ 4. The first and second piezoelectric elements 15 and 16 are used for exciting ultrasonic waves,
Is used for detecting the feedback signal of the excitation amplitude. In addition, the dimensions of the other ultrasonic conduction passage 6 are as follows.
It is preferable that the arc lengths of the semicircular portions 4 and 4 'are 3λ each, the lengths of the long side portions 5 and 5' are 3.5λ each, the entire circumference is 13λ, and the width is an odd multiple of λ / 4.

First piezoelectric element 15 and second piezoelectric element 1
6 is connected to oscillators 18 and 19, and the first piezoelectric element 15
Asin (ωt) and the second piezoelectric element 16 have Asin (ωt ± 90
(°) is applied in the thickness direction with a high-frequency voltage of about 32 KHz shifted in time by ± 90 °. Thereby, an ultrasonic traveling wave is generated on the surface of the elliptical ultrasonic conduction path 6 and circulates through the ultrasonic conduction path 6. The amplitude of the ultrasonic vibration is detected by the third piezoelectric element 17 and fed back to the oscillators 18 and 19 to appropriately control the applied voltage.

The movable element 20 as a driven body is a rail-shaped member having an L-shaped cross section. The mover 20 abuts on the rotary roller 3 and also directly abuts on the surface of the long side portion 5 of the ultrasonic conduction path 6 on the left side in FIG. The mover 20 is guided by a guide roller 21 rotatably provided on the base 7 and is movable in a direction perpendicular to FIG.

FIG. 4 is a plan view showing the entire base 7.
A pulley 22 that supports the lower surface of the mover 20 is provided on the base 7 on the opposite side of the linear ultrasonic motor 1. Then, two sets of the linear ultrasonic motor 1 and the mover 20 are installed on the base 7 of this embodiment, and both are driven simultaneously in the same direction. Such a configuration can be applied to, for example, a driving device for a sunroof of an automobile. The base 7 may be replaced with a sunroof of the automobile, and the mover 20 may be replaced with an L-shaped rail of the main body of the automobile. In this case, since the mover 20 as the L-shaped rail is fixed to the body of the automobile, the base 7 as the sunroof becomes movable.

Next, the operation will be described. A first phase fixed to the bottom surfaces of the long sides 5, 5 'by shifting the phase by 1/4 wavelength;
And the temporal phase of the second piezoelectric elements 15 and 16 is ± 90 °
When a shifted high-frequency voltage is applied, an ultrasonic traveling wave is generated on the surface of the elliptical ultrasonic conduction path 6. The driving force is transmitted to the mover 20 directly contacting the surface of the long side portion 5 by friction in a direction opposite to the traveling direction of the ultrasonic wave by the transversely traveling ultrasonic wave that is bent up and down, and the movable element 20 is moved. It is driven linearly. On the other hand, the driving direction is reversed by the rotating roller 3 at the long side portion 5 ′ on the right side of FIG. 2, and the driving force in the same direction as the long side portion 5 on the left side is transmitted to the mover 20.

In the embodiment described above, the ultrasonic conduction path 6
Is shown as an oval, but of course, the ultrasonic conduction path 6 may be circular. Further, although the guide roller 21 is provided to guide the mover 20 straight, even if the guide roller 21 is not provided, for example, as shown in FIG. 20
May be formed with a straight rail groove 23 that engages with the chamfered portion of the rotating roller 3 and guides the mover 20 linearly by engagement of the two. Further, two or more rotating rollers 3 may be provided, and an endless belt may be stretched between the rotating rollers 3. Further, if the rotation direction of the rotating roller 3 is inclined at an angle θ with respect to the traveling direction of the ultrasonic traveling wave as shown in FIG. 6, the driving direction of the mover 20 is inclined with respect to the traveling direction of the ultrasonic traveling wave. Things can be done easily.

[0016]

According to the present invention, the linear driving force which has the above-mentioned structure and can be concentrated in one direction, which has been conventionally dispersed in the normal and reverse directions, can be reduced while keeping the shape compact. Can be dramatically improved. Moreover, since the structure is simple, there is an effect that the cost is low and the reliability is high. From these facts, the linear ultrasonic motor of the present invention is required to be compact in a small installation space, and further, as a driving device such as a power window, a sunroof, or a sunshade of an automobile which requires a strong linear driving force. Optimal.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a linear ultrasonic motor and a mover,

FIG. 2 is a sectional view taken along line AA of FIG. 1;

FIG. 3 is a bottom view showing the linear ultrasonic motor separated from a base;

FIG. 4 is a plan view showing the entire base.

FIG. 5 is a sectional view of a linear ultrasonic motor and a mover showing another embodiment;

FIG. 6 is a plan view of a rotary roller and an ultrasonic transmission path showing another embodiment.

[Explanation of symbols]

1. . 2. linear type ultrasonic motor, . Rotating roller,
6. . 6. ultrasonic conduction path; . Base, 20. . Mover.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-18533 (JP, A) JP-A-62-178178 (JP, A) JP-A-3-102031 (JP, A) 107289 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02N 2/00 B60J 7/057

Claims (1)

(57) [Claims] An ultrasonic conduction path formed in a substantially oval or circular closed path is provided, and the mover is linearly driven by an ultrasonic traveling wave generated on the surface of the ultrasonic conduction path. in the linear ultrasonic motor, the ultrasonic abuts against the part of the surface of the ultrasonic transmission path
At least one rotating roller supported on a base so as to be driven to rotate by a traveling wave, and a surface of the ultrasonic conduction path on a side facing the rotating roller, and abutting against both the rotating roller. A linear type ultrasonic motor, comprising: