JPH06261565A - Vibrating actuator - Google Patents

Abstract

PURPOSE:To stably drive the title actuator by providing an ovalvibration generation means wherein flexure vibrations, in two mutually different directions, which are generated by a first vibrator and a second vibrator are composed so as to shift their phase and an oval vibration is generated at the free end of the second flexure vibrator. CONSTITUTION:A piezoelectric ceramic plate 3 is pasted on the back of a center beam 2 installed at base stands 1a, 1b, and a first vibrator 4 is formed. Two piezoelectric ceramic plates 5a, 5b are pasted on a fixation part 2a on the surface, and a second flexure vibrator 6 is constituted in an cantilever state. When an AC voltage is applied to the piezoelectric ceramic plate 3, the center beam 2 causes flexure vibrations in the up-and-down direction. When an AC voltage is applied to the piezoelectric ceramic plates 5a, 5b, they cause bend vibrations in arrow directions Ya, Yb. When AC voltages whose phase has been shifted mutually are applied across the piezoelectric ceramic plates 3 and 5a, 5b, a contact member 7 at a free end P causes oval vibrations. As a result, it is possible to stably take out a driving force.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a PPC, printer,
The present invention relates to a vibration actuator used as a drive mechanism for feeding a paper in a field such as a facsimile.

[0002]

2. Description of the Related Art Conventionally, as a vibration actuator using a piezoelectric element, as a first conventional example, Japanese Patent Publication No. 59-37.
No. 672, “Rotation drive device utilizing ultrasonic vibration”
There is something disclosed under the name. This uses a magnetostrictive oscillator as an ultrasonic oscillator that generates ultrasonic waves,
By applying a high-frequency voltage to the coil, the ultrasonic vibrator expands and contracts due to the magnetic field, and the expanding and contracting motion excites the vibration plate attached to the ultrasonic vibrator in the longitudinal direction, resulting in elliptical vibration at its tip. Is generated, and thereby the vibrating piece of the rotating shaft is brought into contact with the vibrating plate of the tip portion that performs the elliptical vibration, whereby the rotating shaft is rotated by the frictional force between the vibrating piece and the vibrating plate.

As a second conventional example, Japanese Patent Laid-Open No. 58-58
There is one disclosed in Japanese Patent No. 148682 under the name "motor device using ultrasonic vibration". this is,
Two electrostrictive elements (or magnetostrictive elements) in a cylindrical bending oscillator
And applying high-frequency voltages having different phases to the electrodes in contact with the two electrostrictive elements to create rotary circular vibration due to bending vibration that is a combination of longitudinal vibration and lateral vibration in the entire bending vibrator. The rotor is rotated by frictional force by bringing the rotor into contact with the bending oscillator that makes the rotational circular vibration.

Furthermore, as a third conventional example, Japanese Patent Publication No. 4-
There is one disclosed in Japanese Patent No. 58273 under the name of "piezoelectric drive device". This is because a piezoelectric element is attached to at least two surfaces of a rod-shaped vibrator having elasticity, and a piezoelectric device on an adjacent surface is made to have a phase difference with each other by a power supply device to generate a high frequency voltage. This is to make a circular or elliptical motion.

In addition to the above-mentioned four conventional examples, there are linear motors (Trikeps, WS132, p.130 to 134) using laminated piezoelectric ceramics. This is because the driving force is obtained by generating elliptical vibration from vibrations in the x and y2 directions, low voltage driving is possible, and drive control can be easily performed.
In addition to this, in order to obtain elliptical vibration, a bending-bending mode / sound piece motor (Trikeps, WS132, p. 132) obtained by exciting two bending (transverse) vibration modes of a sound piece orthogonal to each other with their phases shifted. 141-143). This is a simple mechanism that presses a moving body against elliptical vibration to obtain a driving force.

[0006]

In the case of the first conventional example,
The rotation direction of the rotary shaft is determined by the inclination direction of the vibrating piece that contacts the vibrating plate, and the tip of the vibrating piece is thin, which causes wear due to friction and a long service life.

In the case of the second conventional example, the rotation can be forward or reverse, but it is necessary to always apply energy to the entire bending vibrator, and the surface opposite to the surface of the electrostrictive element stuck to the vibrator is required. It is necessary to absorb the vibration of the surface, which causes a large energy loss and makes it difficult to improve the driving efficiency. In addition, the linear motor has to be configured to circulate the traveling wave, energy loss is too large and no problem occurs, and its circulation method is extremely difficult.

In the case of the third conventional example, since the node portion of the vibrator is used as the supporting portion, the vibration is not hindered, and electric energy is efficiently driven as compared with the first and second conventional examples described above. Can be converted into power. However, since the tip of the oscillator whose one end is a free end draws a conical (in the case of the first-order mode) vibration locus, the part in contact with the moving body is limited to the tip, and both ends are In the fixed oscillator (in the case of the first-order mode), the portion in contact with the moving body is limited to the central portion of the oscillator. In this case, if the contact area between the vibrator and the moving body is not reduced, the portion with a small locus becomes a load instead of a driving force. However, in order to increase the driving force, reduce the wear, and stabilize the slip on the friction surface, that is, the stabilization of the drive, it is preferable that the contact area is large, but this example satisfies the conditions. Absent.

Further, in the case of a linear motor using laminated piezoelectric ceramics, it is possible to make the size of the elliptical locus substantially constant at each point of the contact portion with the moving body. But,
The laminated piezoelectric element has a large electric capacity, and when the driving frequency is in the high frequency (ultrasonic) region, the impedance becomes small,
Since too much current flows, a load is placed on the power source, leading to an increase in size and cost, and the heat generated by the piezoelectric element cannot be overlooked.

[0010]

According to a first aspect of the present invention, there is provided a first flexural vibrator having a first piezoelectric member on a doubly supported beam whose both sides are fixed, and one end fixed to the doubly supported beam and the other end. A second flexural vibrator having a cantilever-shaped second piezoelectric element having a free end, a contact member attached to the free end of the second flexural vibrator, and the second member via the contact member. The second flexure is composed by combining pressure contact means for pressing the free end of the flexural vibrator against the moving body and flexural vibrations in two different directions generated by the first flexural vibrator and the second flexural vibrator with their phases shifted. It is composed of an elliptical vibration generating means for generating an elliptical vibration at the free end of the oscillator.

According to a second aspect of the invention, in the invention of the first aspect, the free end of the second flexural vibrator is supported by a support having elasticity.

According to the invention of claim 3, claim 1 or 2
In the invention described above, a high-friction member having a large friction coefficient is provided on the surface of the contact member in contact with the moving body.

[0013]

According to the first aspect of the present invention, it is possible to create an elliptical locus vibration by synthesizing vibration displacements in two directions by flexural vibration, and the same magnitude is achieved over the entire contact portion of the contact member. Since the elliptical motion of the height is performed, it is possible to secure a wide contact area of the contact member with the moving body, obtain a large output, and reduce wear due to friction.

According to the second aspect of the invention, the flexural vibrator can be protected from an unreasonable load, and the pressure contact force of the pressure contact means can be increased to increase the output.

According to the third aspect of the invention, since the high friction member is provided, the paper can be fed with a simple structure.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIG. Bases 1a and 1b are provided on both left and right sides, and a thin plate-shaped double-supported beam 2 is formed between the bases 1a and 1b. A piezoelectric ceramics plate 3 as a first piezoelectric member is attached to the back surface of the both-supported beam 2. The doubly supported beam 2 and the piezoelectric ceramic plate 3 form a first flexural vibrator 4. Further, two piezoelectric ceramic plates 5a and 5b as a second piezoelectric element are bonded to the fixed portion 2a on the surface of the both-supported beam 2 vertically to the surface thereof, whereby the piezoelectric ceramics are fixed. Plate 5a,
5b is in a cantilevered state with the free end P at the tip. In this case, the piezoelectric ceramic plates 5a and 5b are bonded to each other with their polarization directions opposite to each other, and constitute the second flexural vibrator 6. A contact member 7 is attached to the free end P of the second cantilever-shaped second flexural vibrator 6.

Further, here, flexural vibrations in two different directions generated by the first flexural vibrator 4 and the second flexural vibrator 6 are combined by shifting their phases, and an elliptic vibration is generated at the free end of the second flexural vibrator 6. An elliptic vibration creating means (not shown) is provided for creating

The principle of operation for causing the present vibration actuator to generate the vibration of the elliptic locus by the elliptic vibration creating means in such a configuration will be described. When an AC voltage is applied to the piezoelectric ceramics plate 3, the both-supported beam 2 flexurally vibrates in the vertical direction (direction X perpendicular to the surface). Further, when an AC voltage is applied to the piezoelectric ceramic plates 5a and 5b, the cantilever piezoelectric ceramic plates 5a and 5b move in the arrow directions Ya and Yb.
Bend and vibrate.

In this case, the contact member 7 at the free end P is elliptically oscillated by applying an alternating voltage having a phase difference between the piezoelectric ceramic plate 3 and the piezoelectric ceramic plates 5a and 5b. Specifically, by adjusting the dimensions so that the vertical vibrations of the doubly supported beam 2 and the horizontal vibrations of the piezoelectric ceramics plates 5a and 5b are matched, and performing resonance drive with an AC voltage with a 90 ° phase shift. , Can produce elliptical vibration.

Therefore, the contact portion A (hatched area) of the contact member 7 with the moving body (not shown) is the piezoelectric ceramic plate 5.
Since the elliptical vibration having the same magnitude as that of a and 5b is generated, the contact area can be expanded by the width W of the piezoelectric ceramic plates 5a and 5b, thereby securing a large contact area with the moving body and obtaining a large output. be able to.

Next, a second embodiment of the present invention will be described with reference to FIG. This embodiment shows an application example of the first embodiment described above. That is, a pressure contact mechanism 8 as a pressure contact means is provided above the contact member 7. The pressure contact mechanism 8 includes a leaf spring 8a and a roller 8b rotatable by a bearing (not shown). The pressure contact mechanism 8 presses a movable body 9 made of a prismatic metal rod against the free end P side of the contact member 7. As a result, this apparatus constitutes a linear motor that drives the moving body 9 linearly (Ya, Yb directions). The moving body 9 is provided with a guide mechanism (not shown).

In the linear motor having such a structure, the piezoelectric ceramic plate 3 and the piezoelectric ceramic plate 5
It is possible to linearly move the moving body 9 in contact with the contact member 7 in the Ya direction (solid line) by causing the a and 5b to be 90 degrees out of phase with each other and to be resonantly driven by an AC voltage.
When the phase difference is reversed (-90 °), the moving direction of the moving body 9 can be reversed and the moving body 9 can be linearly moved in the Yb direction (broken line).

Therefore, it is possible to easily realize a miniaturized and thinned linear motor with a simple structure. Further, since the contact area between the contact member 7 and the moving body 9 can be widened, the output can be increased and the driving efficiency can be increased for the size of the actuator. Further, since the slip on the friction surface is averaged, the operation of the actuator is stable and the reliability can be improved.

Next, a third embodiment of the present invention will be described with reference to FIG. This embodiment shows another application example of the first embodiment, similarly to the configuration of FIG. That is, the moving body 10 (rotor side) is arranged above the contact member 7 (stator side). The moving body 10 includes a shaft 10 rotatably supported via bearings (not shown).
a and a pulley 10b joined to the shaft 10a. Further, a spring 12 as a pressure contact means is provided between the lower surface of the base 1a and the base 11, and the other base 1b side is rotatably supported by a rotating mechanism 13. And the spring 12 is the base 1a
By pushing up, the contact member 7 is pressed against the moving body 10 side. As a result, the present device constitutes a rotary actuator that takes out rotational force from the pulley 10b.

In the rotary actuator having such a structure, the piezoelectric ceramics plate 3 and the piezoelectric ceramics plate 5 are operated according to the same principle as that of the linear motor shown in FIG.
By driving a and 5b, the shaft 10a of the moving body 10 can be rotated well, and the same effect as that of the second embodiment can be obtained.

Next, a fourth embodiment of the present invention will be described with reference to FIG. The present embodiment shows an example in which a stator is configured based on the basic configuration of FIG. 1 described above. Supports 14a and 14b are integrally attached to both side surfaces of the contact member 7, and the supports 14a and 14b are attached together.
The other end side of is fixed to the upper part of the bases 1a and 1b. In this case, the supports 14a and 14b are formed in a thin plate shape by cutting a part thereof so as to have appropriate elasticity. The reason for providing such supports 14a and 14b is as follows.
The piezoelectric ceramic plate 3 or the piezoelectric ceramic plate 5 is limited by limiting the deformation amount of the vibrator in consideration of the case where an unreasonable load is applied to the vibrator (first flexural vibrator 4, second flexural vibrator 6).
This is to prevent damage to a and 5b. Also,
Along with this, it is also possible to prevent the torsional vibration of the second flexural vibrator 6 that flexurally vibrates and the generation of an unnecessary vibration mode.

By using the stator thus constructed,
When the above-mentioned linear motor (see FIG. 2) or rotary type actuator (see FIG. 3) is configured, it is possible to suppress the generation of unnecessary vibration modes and stabilize the operation, and a good condition is obtained for both devices. The driving force can be taken out with. Further, by providing the supports 14a and 14b in this way, the pressure contact force with the moving bodies 9 and 10 can be further increased, and the output can be improved.

Next, a fifth embodiment of the present invention will be described with reference to FIG. This embodiment shows an application example in which a paper feed mechanism for directly driving the paper 15 in the Ya and Yb directions is realized by using the stator shown in FIG. That is, the upper surface of the contact member 7 is coated with a high-friction member (μ rubber) 7a having a large coefficient of friction with the paper 15 as the moving body. Further, the pressure contact mechanism 1 as the pressure contact means here.
6 is a leaf spring 16a and a roller 1 rotatably supported.
It consists of 6b. The roller 16b applies pressure to the contact member 7 with a relatively weak force.

In such a structure, by driving the piezoelectric ceramics plate 3 and the piezoelectric ceramics plates 5a and 5b of the stator, the contact member 7 generates an elliptical locus vibration, and the elliptical vibration causes the roller 16b to rotate. To do.
By directly inserting the paper 15 between the rotating roller 16b and the contact member 7, the paper 15 can be sent out in the Ya direction (solid line). Further, the paper 15 can be sent out in the opposite Yb direction (broken line) by applying a voltage of opposite phase. In this case, the roller 16b has a shape that rotates with the movement of the paper 15.

As described above, by providing the high friction member 7a having a large friction coefficient, the paper 15 can be fed by a simple mechanism, thereby realizing a paper feeding mechanism which can be made compact and thin. be able to.

Next, a sixth embodiment of the present invention will be described with reference to FIG. This embodiment shows another application example of the stator shown in FIG. That is, the cantilever beam 17 is integrally formed on the upper surface of the both-end supported beam 2 in the vertical direction (X direction). Piezoelectric ceramic plates 5a and 5b are attached to both side surfaces of the cantilever 17, which is in the form of a so-called bimorph flexural vibrator. In this case, the cantilever 17 and the piezoelectric ceramic plate 5
a and 5b form the second flexural vibrator 6. A contact member 7 is attached to the free end P of the tip of the cantilever 17, and the contact member 7 has an elastic support member 14
It is fixed to the upper portions of the bases 1a and 1b via a and 14b.

By using the bimorph type stator having the above structure to drive the linear motor (see FIG. 2) and the rotary actuator (see FIG. 3) described above, the second embodiment described above is performed. The effects as described in the examples to the fourth embodiment can be obtained.

[0033]

According to the first aspect of the present invention, a first flexural vibrator having a first piezoelectric member on a double-supported beam whose both sides are fixed, and one end fixed to the both-supported beam and the other end being a free end. A second flexural vibrator having a cantilever-shaped second piezoelectric element, a contact member attached to a free end of the second flexural vibrator, and a second flexural vibrator of the second flexural vibrator via the contact member. The pressure contact means for pressing the free end against the moving body and the flexural vibrations in the two different directions generated by the first flexural vibrator and the second flexural vibrator are combined by shifting the phases, and the freedom of the second flexural vibrator is obtained. Since it is composed of the elliptical vibration generating means for generating the elliptical vibration at the end, it is possible to realize the vibration actuator with a relatively simple structure by combining the vibration displacements in the two directions by the flexural vibration to generate the vibration of the elliptical locus. , Since the same size elliptic motion is performed over the entire contact portion of the contact member, a large contact area between the contact member and the moving body can be secured, a large output can be obtained, and wear due to friction can be reduced. further,
Since the slip on the friction surface is averaged and stable, the driving force can be stabilized and taken out.

According to the invention described in claim 2, in the invention described in claim 1, since the free end of the second flexural vibrator is supported by the elastic support, the operation is performed while suppressing generation of unnecessary vibration modes. The flexural vibrator can be stabilized and protected from an unreasonable load, and the pressure contact force of the pressure contact means can be increased to increase the output.

According to a third aspect of the present invention, in the first or second aspect of the invention, a high-friction member having a large friction coefficient is provided on the surface of the contact member in contact with the moving body. Therefore, the paper feed mechanism can be made smaller and thinner.

[Brief description of drawings]

FIG. 1A is a plan view showing a basic configuration of a vibration actuator according to a first embodiment of the present invention, and FIG. 1B is a front view thereof.

FIG. 2 is a front view showing a configuration of a linear motor that is a second embodiment of the present invention.

FIG. 3 is a front view showing a rotary actuator that is a third embodiment of the present invention.

FIG. 4 is a perspective view showing a stator which is a fourth embodiment of the present invention.

FIG. 5 is a front view showing a paper feeding mechanism configured by using a stator that is a fifth embodiment of the present invention.

FIG. 6 is a front view showing a modification of the stator shown in FIG. 4, which is the sixth embodiment of the present invention.

[Explanation of symbols]

 2 Double-supported beam 3 1st piezoelectric member 4 1st deflection oscillator 5a, 5b 2nd piezoelectric member 6 2nd deflection oscillator 7 Contact member 7a High friction member 8 Pressure contact means 9, 10 Moving body 12 Pressure contact means 14a, 14b Support Body 15 Moving body 16 Pressure contact means P Free end

Claims (3)

[Claims] 1. A first flexural vibrator having a first piezoelectric member on a double-supported beam whose both sides are fixed, and a first cantilever-shaped beam having one end fixed to the both-support beam and the other end being a free end. A second flexural vibrator having two piezoelectric elements, a contact member attached to the free end of the second flexural vibrator, and the free end of the second flexural vibrator pressed against the moving body via the contact member. Elliptical vibration for generating elliptical vibration at the free end of the second flexural vibrator by combining flexural vibrations in two different directions generated by the pressure contact means, the first flexural vibrator and the second flexural vibrator by shifting the phases. A vibration actuator comprising: a creating unit. 2. The vibration actuator according to claim 1, wherein the free end of the second flexural vibrator is supported by a support having elasticity. 3. The vibration actuator according to claim 1, wherein a high-friction member having a large friction coefficient is provided on the surface of the contact member that is in contact with the moving body.