JP2533044Y2 - 2-speed variable bidirectional ultrasonic linear 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 variable speed ultrasonic linear motor, and more particularly to a two-speed variable bidirectional ultrasonic linear motor having a simple driving source circuit.

[0002]

2. Description of the Related Art As a conventional variable speed system of an ultrasonic motor, a variable voltage system or the like has been used. In such a voltage variable system, it is necessary to add a speed variable circuit to the drive circuit as shown in FIG. 5, and there has been a problem that the circuit becomes complicated and the cost increases.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object the purpose of being able to easily achieve high-speed and low-speed two-speed variable operation with a simple circuit. It is an object of the present invention to provide a variable speed bidirectional ultrasonic linear motor.

[0004]

The two-speed variable bi-directional ultrasonic linear motor of the present invention has a plurality of piezoelectric vibrators arranged at equal intervals in the direction of polarization, and one electrode is joined to a linear elastic band. The piezoelectric vibrators of the obtained linear band vibrator are arranged in the order of arrangement as an a-phase vibrator, a neutral vibrator, and a b-phase vibrator, and the output terminal of the a-phase ultrasonic electric signal source is the other electrode of the a-phase vibrator. In addition, a ground terminal is connected to the other electrode of the neutral vibrator, and a phase difference of 2 / π with respect to the a-phase ultrasonic electric signal source can be selectively provided on the leading side or the lagging side so that the b-phase can be provided. The output terminal of the sonic electric signal source is connected to the other electrode of the b-phase vibrator, and the ground terminal is connected to the other electrode of the neutral vibrator, and opened and closed between the other electrode of the neutral vibrator and the linear elastic band. Connect the switch and press the moving body against multiple protrusions provided on the linear belt-shaped elastic Ri is for driving the movable body.

[0005]

When the vibration of the piezoelectric vibrator is applied to the linear belt-like elastic body, a standing wave is generated in the linear belt-like elastic body. The standing waves appear one by one corresponding to the output of the ultrasonic electric signal source, and the phase difference becomes 2 / π, which is the same as the phase difference of the ultrasonic electric signal source, and these standing waves are combined to form a traveling wave. Becomes The traveling direction of the traveling wave changes depending on the sign of the phase difference between the two standing waves.
By such a traveling wave, the tip of the projection of the linear band-shaped elastic body is moved in an elliptical shape, and the moving body is sent in a direction opposite to the traveling direction of the traveling wave. The acceleration of the ultrasonic vibration is very large, and the moving body generates delayed sliding friction from the movement of the projection of the linear belt-shaped elastic body. Assuming that the pressure and friction coefficient for pressing the moving object are constant,
The speed of the moving body is determined by the amplitude of the linear belt-shaped elastic body.

When the open / close switch connected between the electrode of the neutral oscillator and the linear elastic band is open, the a-phase and b-phase piezoelectric oscillators are connected in series with the neutral oscillator, respectively. When connected to the b-phase ultrasonic electric signal source and the same open / close switch is closed, the a-phase and b-phase piezoelectric vibrators are directly connected to the a-phase and b-phase ultrasonic electric signal sources, respectively. The applied voltage in each case changes, and thus the amplitude also changes.

As described above, the amplitude of the piezoelectric vibrator can be changed only by operating the open / close switch, and the amplitude of the projection of the linear band can be changed to change the speed of the moving body.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A two-speed variable bidirectional ultrasonic linear motor which is an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an embodiment. In the figure, reference numeral 1 denotes a linear elastic band made of stainless steel;
a, 3b and 3c are joined at equal intervals to form a linear band-shaped vibrator. The negative poles of the piezoelectric vibrators 3a, 3b and 3c are electrically connected to the linear elastic band. The positive poles of the piezoelectric vibrators 3a and 3b are connected to the output terminals of the ultrasonic electric signal sources 6 and 7, respectively, via the conductive wire 4, and the ground terminals of the ultrasonic electric signal sources 6, 7 are connected through the conductive wire 4. Connected to the positive pole of the piezoelectric vibrator 3c. In addition, the ground side terminals of the linear belt-shaped elastic body and the ultrasonic electric signal sources 6 and 7 are connected to both contacts of the open / close switch 5. The moving body 2 is pressed against the protrusions 1a provided on the linear belt-shaped elastic body 1.

In the above configuration, the ultrasonic electric signal sources 6 and 7 are a-phase and b-phase ultrasonic electric signal sources, respectively, and have a phase difference of π / 2. When the phase of the output signal of the ultrasonic electric signal source 7 is advanced by π / 2 from the phase of the output signal of the ultrasonic electric signal source 6 and applied to the piezoelectric vibrator, the linear band elastic body 1 has a phase difference of π / 2 of 2 Two standing waves are generated, and a wave obtained by combining them becomes a traveling wave. As shown in FIG. 2A, the protrusion 1a moves according to the elliptical locus of the left rotation, and the moving body 2 pressurized by the load of P a letter by a frictional force to F _L direction. When the phase of the output signal of the ultrasonic electric signal source 7 is delayed by π / 2 from the phase of the output signal of the ultrasonic electric signal source 6 and applied to the piezoelectric vibrator, as shown in FIG. 1a
The motion according to the ellipse trajectory of the right rotation, sends the moving body 2 is pressurized with a load of P into F _R direction by a frictional force.

FIG. 3 shows the characteristics of the thrust F and the speed v with respect to the load P. When the open / close switch 5 is open, the characteristics of the thrust F and the speed v with respect to the load P are as shown in FIG.
₂ and v ₂ , and when the open / close switch 5 is closed, the curves are F ₁ and v ₁ . The output voltages of the ultrasonic electric signal sources 6 and 7 are 55 V, and the frequency is 62.6 kHz.

When the open / close switch 5 is closed, the output voltages of the ultrasonic electric signal sources 6 and 7 are directly applied to the piezoelectric vibrators 3a and 3b, and the amplitude of the linear belt-shaped elastic body 1 is large and large for the moving body 1. Thrust and speed are obtained. When the open / close switch 5 is open, the piezoelectric vibrators 3a and 3b are connected in series with the piezoelectric vibrator 3c by the ultrasonic electric signal source 6.
Since the output voltages of (1) and (2) are directly applied, the amplitude of the linear belt-shaped elastic body 1 is reduced, and the thrust and speed of the moving body 1 are also reduced. At this time, a voltage having a phase different from the a-phase and the b-phase is applied to the piezoelectric vibrator 3c to expand and contract, thereby contributing to the vibration of the protrusions 1a.

As described above, the speed variable circuit of the ultrasonic linear motor only needs to connect the open / close switch 5 as shown in FIG.
Different speeds can be obtained, which is simpler than the conventional one.

[0013]

According to the two-speed variable bidirectional drive ultrasonic linear motor of the present invention, two types of speeds, high speed and low speed, can be obtained only by opening and closing the switch. Since it is not required, the drive circuit of the ultrasonic linear motor is inexpensive.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a two-speed variable bidirectional drive ultrasonic linear motor according to an embodiment of the present invention.

FIG. 2 is a partial sectional view showing the operation of the embodiment.

FIG. 3 is a graph showing operation characteristics of the embodiment.

FIG. 4 is a block diagram showing a drive source circuit of the embodiment.

FIG. 5 is a block diagram illustrating an example of a drive source circuit of a conventional ultrasonic linear motor.

[Description of Signs] 1 Linear band elastic body 1a Projection 2 Moving body 3a Piezoelectric vibrator 3b Piezoelectric vibrator 3c Piezoelectric vibrator 4 Conductive wire 5 Opening / closing switch 6 Ultrasonic electric signal source 7 Ultrasonic electric signal source

Claims (1)

(57) [Scope of request for utility model registration] 1. An a-phase vibrator of a linear band-shaped vibrator obtained by joining one electrode to a linear band-shaped elastic body by aligning a plurality of piezoelectric vibrators at equal intervals in the direction of polarization, A neutral oscillator, a b-phase oscillator, an output terminal of the a-phase ultrasonic electric signal source is connected to the other electrode of the a-phase oscillator, and a ground terminal is connected to the other electrode of the neutral oscillator. The output terminal of the b-phase ultrasonic electric signal source capable of selectively providing a phase difference of 2 / π with the ultrasonic electric signal source on the leading side or the lagging side is grounded to the other electrode of the b-phase vibrator. A terminal is connected to the other electrode of the neutral oscillator, an open / close switch is connected between the other electrode of the neutral oscillator and the linear elastic member, and the moving body is connected to the plurality of protrusions provided on the linear elastic member. A two-speed variable bidirectional ultrasonic linear motor that drives a moving body by frictional force by pressing.