JPH044774A - Ultrasonic linear motor - Google Patents

Abstract

PURPOSE:To control the moving speed of a slider to a predetermined speed, to control the slider at a predetermined holding force and to hold it by varying the pressing force of the slider in pressure contact with a transmission rod, and controlling the driving force and the holding force of the slider. CONSTITUTION:A slider 4 is pressed by a pressure regulating mechanism 5 to be driven by regulable fluid pressure, and the pressing force of the slider 4 in pressure contact with a transmission rod 3 is varied by the pressing of the mechanism 5. Thus, the driving force, the holding force of the slider to be determined by a friction coefficient between the rod 3 and the slider 4, the pressing force can be controlled.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an ultrasonic linear motor, and in particular, in a pressurizing structure between a slider and a transmission rod, the pressing force of the slider that is brought into pressure contact with the transmission rod is variable. The present invention relates to a technique that is effective when applied to an ultrasonic linear motor that enables control of the driving force and holding force of a slider.

[Prior art] As a conventional ultrasonic linear motor, for example,
9-122385, Japanese Patent Application Laid-Open No. 60-22478, etc., have been proposed that use an ultrasonic motor that utilizes the strong vibrational energy of ultrasonic waves.

Its outline includes, for example, two sets of piezoelectric vibrators excited by the application of a high-frequency voltage, a transmission rod fixed to these two sets of piezoelectric vibrators, and a slider that is brought into pressure contact with the transmission rod. Due to the excitation of the piezoelectric vibrator to which one high-frequency power source is applied, transverse vibration and longitudinal vibration are generated on the transmission rod.
An elliptical vibration with a phase shift of 0 degrees is formed, and this elliptical vibration is propagated as a traveling wave in one direction on the transmission rod, and is absorbed by the piezoelectric vibrator connected to the other load resistance. Furthermore, this traveling wave is formed in the same way at any point on the transmission rod, and in this state, the slider is contacted only at the peak of the traveling wave, and the friction with the transmission rod creates a thrust force in the opposite direction to the traveling wave on the slider. generated. As a result, the slider is driven in the opposite direction to the traveling wave and converted into rotational or linear motion.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional technology, the slider is brought into pressure contact with the transmission rod via an elastic member such as a spring, and the slider is driven in a predetermined direction by the pressing force of the spring. can be done. That is, although a constant driving force can be obtained by the compression force of the spring, there is a problem in that the driving force of the slider cannot be varied as necessary.

Therefore, the present inventor focused on the fact that the driving force of the slider is determined by the following formula, and found that when the coefficient of friction is constant, the driving force can be controlled by varying the pressing force of the slider.

F (driving force) = μ (W!! Friction coefficient) × N (crimping force) In other words, the object of the present invention is to vary the pressing force of the slider that is brought into pressurized contact with the transmission rod, and to improve the driving force and holding of the slider. An object of the present invention is to provide an ultrasonic linear motor whose force can be controlled.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means for Solving the Problems] Among the inventions disclosed in this application, a brief overview of typical inventions is as follows.

That is, the ultrasonic linear motor of the present invention includes a first piezoelectric vibrator and a second piezoelectric vibrator excited by application of a high frequency voltage, and a transmission rod fixed to the first and second piezoelectric vibrators. and a slider that is brought into pressure contact with the transmission rod, and a unidirectional traveling wave is formed on the transmission rod by exciting either the first or second piezoelectric vibrator, and an ultrasonic linear motor in which the traveling wave generates a thrust in the opposite direction to the traveling wave in the front slider, and the thrust drives the slider in the opposite direction to the traveling wave, and the slider is adjusted. The slider is pressed by a pressure regulating mechanism driven by the available fluid pressure, and the pressure of the pressure regulating mechanism varies the pressure force of the slider before it comes into pressurized contact with the transmission rod, and the slider has a predetermined driving force and pressure. It is controlled by the holding force.

Further, when the pressure force of the slider is set to a predetermined pressure force that can be stopped, the slider can be stopped with a predetermined holding force.

Furthermore, when the pressing force of the slider is set to zero, the slider can be easily driven manually.

[Function] According to the above-mentioned ultrasonic linear motor, the slider is pressed by the pressure regulating mechanism driven by adjustable fluid pressure, and the pressure of the pressure regulating mechanism increases the crimping force of the slider that is brought into pressurized contact with the transmission rod. By varying this, it is possible to control the driving force and holding force of the slider, which are determined by the friction coefficient and pressure force between the transmission rod and the slider. Thereby, the driving speed of the slider can be controlled to a predetermined speed, and at the same time, the slider can be held with a predetermined holding force.

In addition, when the pressure force of the slider is set to a predetermined force capable of stopping the slider, the slider can be stopped at a predetermined position with a predetermined holding force.

Furthermore, when the pressure force of the slider is set to zero, the slider can be easily manually driven in a predetermined direction.

[Example] Fig. 1 is a partial sectional view showing the main parts of an ultrasonic linear motor according to an embodiment of the present invention, and Fig. 2 is a schematic configuration diagram showing a circuit of the ultrasonic linear motor according to the present embodiment. .

First, the configuration of the ultrasonic linear motor of this embodiment will be explained with reference to FIG.

The ultrasonic IJ near motor of this embodiment is, for example, an ultrasonic linear motor using a cylinder device as an example of a pressure regulating mechanism, and the first piezoelectric vibrator 1 shown in FIG. 2 is excited by application of a high frequency voltage. and a second piezoelectric vibrator 2, a transmission rod 3 fixed to the first and second piezoelectric vibrators 1 and 2, and a slider 4 brought into pressure contact with the transmission rod 3. There is. Three cylinder devices 5 are fixed to the slider 4.

The first and second piezoelectric vibrators 1 and 2 are formed into a cylindrical shape by bolting, for example, Langevin type vibrators from both ends, and are fixed at nodes of longitudinal vibration. The structure is such that it is excited around a fixed base point by applying a high frequency voltage.

The transmission rod 3 is made of aluminum or the like and has a prismatic shape, and both ends of the transmission rod 3 are fixed to one ends of the first and second piezoelectric vibrators 1 and 2, respectively. and,
For example, by excitation of the first piezoelectric vibrator 1 on the oscillation side, a traveling wave is formed on the transmission rod 3 that vibrates along its axial direction, and the traveling wave is absorbed by the second piezoelectric vibrator 2 on the absorption side. The structure is such that

The slider 4 is formed into a rectangular tube shape made of aluminum, for example, and has three cylinder devices 5 fixed to its upper surface, and the slider 4 is brought into pressure contact with the transmission rod 3 by the pressure of these cylinder devices 5. There is. The traveling wave formed on the transmission rod 3 generates a thrust in the direction opposite to the traveling wave, and the slider 4 is driven in the opposite direction to the traveling wave.

Further, a holding plate 6 is interposed between the internal top surface of the slider 4 and the transmission rod 3, and pressurizes the transmission rod 3 by the pressure of the cylinder device 5. A pressure bonding material 7, such as a friction cloth, is applied to the contact surface.

In the cylinder device 5, a cylinder body 5a is fixed to the slider 4, and a movably built-in piston rod 5b is protruded by supplying and discharging fluid pressure. When the piston rod 5b is projected, the holding plate 6 is displaced toward the transmission rod 3, and the slider 4 is brought into pressure contact with the transmission rod 3.

Further, a fluid piping 8 is connected to the cylinder device 5, and fluid pressure is supplied and discharged from a fluid pressure source via a fluid pressure circuit including a proportional control valve (not shown) and the like. By adjusting the fluid pressure, the pressing force of the slider 4 is varied, and the driving force and holding force of the slider are controlled.

The ultrasonic linear motor of this embodiment configured as described above includes, for example, the first and second piezoelectric vibrators 1 and 2, a high frequency power source 9, a changeover switch 10, and a load resistor 11 as shown in FIG. are connected, and the drive direction of the slider 4 can be switched by the changeover switch 10.

Next, the operation of this embodiment will be explained.

First, the changeover switch 10 is set to the state shown in FIG. 2, that is, a closed circuit in which the high frequency power source 9 is connected to the first piezoelectric vibrator 1, and the voltage applied by the high frequency power source 9 is supplied to the first piezoelectric vibrator 1. . The first piezoelectric vibrator 1 on the oscillation side to which the voltage is applied is excited in the direction of the solid arrow around the fixed base point.

At this time, no high frequency voltage is applied to the second piezoelectric vibrator 2, and the load resistor 11 having a predetermined resistance value is connected.

Furthermore, due to the excitation of the first piezoelectric vibrator 1, the surface of the transmission rod 3 fixed to the first piezoelectric vibrator 1 is caused to move in the right direction by elliptical vibration with a phase shift of 90 degrees due to horizontal vibration and longitudinal vibration. A traveling wave is formed and absorbed by the second piezoelectric vibrator 2 on the absorption side. Then, the slider 4 that is brought into pressure contact with the transmission rod 3 is driven in the opposite direction to the traveling wave formed on the transmission rod 3, that is, to the left. As a result, the slider 4 is stably linearly driven to the left at a constant speed.

In this case, the pressing force of the slider 4 that is pressed into contact with the transmission rod 3 can be adjusted by a fluid pressure circuit (not shown) such as a proportional control valve connected to the cylinder device 5. For example, the pressing force of the slider 4 can be increased by increasing the fluid pressure to the cylinder device 5 and increasing the pressing force of the presser plate 6. Thereby, the driving force of the slider 4 can be increased. At the same time, the holding force of the slider 4 is increased, and the slider 4 can be stopped at a predetermined position at a predetermined holding force or higher.

Conversely, when the fluid pressure to the cylinder device 5 is reduced, the driving force of the slider 4 can be reduced. Furthermore, when the pressing force of the slider 4 is made zero, the driving force of the slider 4 is made zero, so that the slider 4 can be easily moved manually.

Next, when the changeover switch 10 is changed from the state shown in FIG. 2 to the state shown by the dotted line, that is, when the changeover switch 10 is changed to a closed circuit in which the high frequency power source 9 is connected to the second piezoelectric vibrator 2, the voltage is changed in the same way as above. is applied to the second piezoelectric vibrator 2 on the oscillation side, a traveling wave is formed on the surface of the transmission rod 3 in the opposite direction to the upper part, that is, to the left, and the slider 4 is driven to the left. is driven to the right.

In this way, the slider 4 can be driven along the axial direction by controlling the predetermined driving force and holding force by switching the changeover switch 10, so that, for example, a slide table in which a table (not shown) or the like is linked to the slider 4 can be used. When used for this purpose, it is possible to transport an object placed on the table in a speed-controllable manner within the drive range of the table.

Therefore, according to the ultrasonic linear motor of this embodiment, the slider 4 that is brought into pressurized contact with the transmission rod 3 is pressurized by the piston rod 5b of the cylinder device (pressure adjustment mechanism) 5 via the presser plate 6. The driving force and holding force of the slider 4 can be controlled by adjusting the pressing force of the slider 4 by the fluid pressure supplied to and discharged from the cylinder device 5. Therefore, the slider 4 can be controlled to a predetermined driving speed. It can be driven in a predetermined direction.

At the same time, the slider 4 can be stopped at a predetermined position when the holding force exceeds a predetermined stopping force. Further, when the pressure force of the slider 4 is set to zero, the slider 4 can be easily driven manually in a predetermined direction.

Above, the invention made by the present inventor has been specifically explained based on examples, but the present invention is not limited to the above-mentioned examples, and it is understood that various changes can be made without departing from the gist of the invention. Needless to say.

For example, regarding the ultrasonic linear motor of this example,
Although the case in which the cylinder device 5 is used as an example of the pressure regulating mechanism has been described, the present invention is not limited to the above-mentioned embodiment. It is widely applicable to pressure mechanisms.

Although we have explained the case where the cylinder device t5 is attached only to the upper surface side of the slider 4, it is also applicable to the case where the cylinder device t5 is attached to both the upper surface side and the lower surface side of the slider 4. Since it is possible to achieve uniformity, stable driving and holding are possible.

Furthermore, the number of cylinder devices 5 is not limited to three, and this also applies to the case where two or four or more cylinder devices 5 are installed. It becomes possible to equalize the force.

Furthermore, in this embodiment, a case has been described in which a fluid pressure circuit (not shown) consisting of a proportional control valve or the like is connected to the cylinder cover 5, which is a pressure regulating mechanism. It is also possible to apply the present invention to a structure in which fluid pressure is supplied and discharged by using the same method, and in this case, the fluid piping 8 is not required, so space restrictions such as installation are alleviated.

Furthermore, the ultrasonic linear motor of this embodiment is not limited to the structure and shape shown in FIG. 1, and the circuit for driving the ultrasonic linear motor may also have a circuit configuration as shown in FIG. 2. It is not limited to.

[Effects of the Invention] Among the inventions disclosed in this section (2), the effects obtained by typical inventions are briefly explained below.

(1) A first piezoelectric vibrator and a second piezoelectric vibrator excited by application of a high frequency voltage, a transmission rod fixed to these first and second pressure 1i vibrators, and this transmission rod A slider is brought into pressure contact with the transmission rod, and when either the first or second piezoelectric vibrator is excited, a unidirectional traveling wave is formed on the transmission rod, and this traveling wave causes the slider to In an ultrasonic linear motor, a thrust force in the opposite direction to the traveling wave is generated, and this thrust drives the slider in the opposite direction to the traveling wave. The pressing force of the slider, which is brought into pressure contact with the transmission rod, is varied by the pressure of the pressure regulating mechanism, thereby controlling the driving force and holding force of the slider, which are determined by the friction coefficient and pressing force between the transmission rod and the slider. Therefore, the drive speed of the slider can be controlled to a predetermined speed, and at the same time, the slider can be controlled to a predetermined holding force and held.

(2) 2 If the crimp force of the slider is set to a predetermined crimp force that can stop the slider, the slider can be stopped at a predetermined position with a predetermined holding force, so an ultrasonic linear motor with a brake function can be used. Obtainable.

(3) When the pressure force of the slider is set to zero, the slider can be easily driven manually in a predetermined direction, making it possible to obtain an ultrasonic linear motor that is well suited for maintenance and adjustment. .

(4) According to (1) to (3) above, in the pressurizing structure between the slider and the transmission rod, a superstructure equipped with a clutch function that enables speed control and stopping by adjusting the fluid pressure to the pressure regulating mechanism. You can get a sonic linear motor.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing essential parts of an ultrasonic linear motor according to an embodiment of the present invention, and FIG. 2 is a schematic configuration diagram showing a circuit of the ultrasonic linear motor according to the present embodiment. DESCRIPTION OF SYMBOLS 1... First piezoelectric vibrator, 2... Second piezoelectric vibrator, 3... Transmission rod, 4... Slider, 5... Cylinder device (&ii pressure mechanism), 5a... cylinder body, 5b...piston rod, 6...pressing plate, 7...crimping material, 8...fluid piping, 9...high frequency power supply, 10...changeover switch, 11...load resistance .

Claims (3)

[Claims] 1. A first piezoelectric vibrator and a second piezoelectric vibrator excited by application of a high frequency voltage, a transmission rod fixed to the first and second piezoelectric vibrators, and a transmission rod brought into pressure contact with the transmission rod. a slider, a unidirectional traveling wave is formed on the transmission rod by exciting either the first or second piezoelectric vibrator, and the traveling wave causes the slider to receive the traveling wave. an ultrasonic linear motor that generates a thrust in a direction opposite to that of the traveling wave, and that drives the slider in a direction opposite to the traveling wave; the slider is pressed by a pressure regulating mechanism that is driven by an adjustable fluid pressure; An ultrasonic linear motor characterized in that the pressing force of the slider brought into pressure contact with the transmission rod is varied by the pressure of the pressure regulating mechanism, and the slider is controlled to a predetermined driving force or holding force. . 2. 2. The ultrasonic linear motor according to claim 1, wherein the slider can be stopped with a predetermined holding force when the slider has a predetermined pressure that can be stopped. 3. Claim 1, wherein the slider can be easily driven manually when the pressing force of the slider is zero.
Ultrasonic linear motor described.