JPH10226196A - Ultrasonic marking device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic marking device for engraving the surface of a metal or a resin. SOLUTION: One of the electrodes of a piezoelectric material vibrator 1 is grounded, while the other electrode is connected to the output terminal of a drive circuit 2 whose input terminal is connected to the output terminal of a voltage control oscillator 3. In addition, a current signal detecting circuit 6 comprising a resistance 4 and a capacitor 5 is connected to the drive circuit 2. Further, the input terminal of a feedback signal amplifier 7 is connected to the current signal detecting circuit 6 and also a phase correcting circuit 8 is connected to the output terminal of the feedback signal amplifier 7. Besides, the output terminal of the phase correcting circuit 8 is connected to one of the input terminals of a phase comparator 9 and an output from the voltage control oscillator 3 is connected to the other input terminal of the phase comparator 9. The output terminal of the phase comparator 9 is connected to the input terminal of a low pass filter 10, while the output terminal of the low pass filter 10 is connected to the input terminal of the voltage control oscillator 3. Finally, the piezoelectric material vibrator 1 is connected to the stylus not illustrated of the ultrasonic marking device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic marking apparatus for engraving characters and symbols on the surface of a metal such as aluminum, iron or stainless steel or a resin.

[0002]

2. Description of the Related Art Conventionally, as a marking device, a stylus (a needle-like tool for engraving) is vibrated by a piezoelectric vibrator in order to engrave characters and symbols on the surface of a plate made of aluminum, iron, resin, or the like. An apparatus has been proposed in which the surface of a plate to be processed is shaved and engraved by the vibration of the stylus.

[0003]

However, in such a marking device, when engraving on a work plate, the stylus wears and becomes shorter, and the resonance frequency of the stylus changes accordingly. Therefore, the conventional self-excited oscillation circuit used in the ultrasonic marking device has a disadvantage that the range in which such a change in the resonance frequency is tracked is narrow, and stable vibration cannot be obtained even with a slight wear of the stylus. In addition, when the frequency tracking is not accurately performed by changing the resonance frequency, the device oscillates abnormally, and the piezoelectric vibrator is damaged.

[0004]

According to the present invention, there is provided a marking device for engraving characters and symbols on an object by vibrating a marking tool with a piezoelectric vibrator, and a driving circuit for driving the piezoelectric vibrator. A voltage-controlled oscillator that supplies high-frequency vibration power to a drive circuit, a current signal detection circuit that detects a current signal applied from the drive circuit to the piezoelectric vibrator, and a feedback signal that amplifies an output of the current signal detection circuit An amplifier circuit, a phase correction circuit for correcting a phase of an output of the feedback signal amplifier circuit, a phase comparator for comparing a phase of an output of the phase correction circuit with a phase of an output of the voltage controlled oscillator, and the phase comparator And a low-pass filter for removing a high-frequency component from the output and supplying a control voltage to the voltage-controlled oscillator.

[0005]

According to the present invention, the output of the voltage controlled oscillator is input to the driving circuit, the output of the driving circuit is input to the piezoelectric vibrator, and the current flowing from the driving circuit to the piezoelectric vibrator is used as a feedback signal by the current signal detector. The feedback signal is amplified by a feedback signal amplifier, the amplified feedback signal is phase-corrected by a phase correction circuit, and input to a phase comparator of the phase-corrected signal and the output of a voltage controlled oscillator. After comparing the phases and removing the high-frequency signal from the phase difference signal from the phase comparator with a low-pass filter, the signal is input to the voltage-controlled oscillator, and the phase of the output of the voltage-controlled oscillator is controlled. Stable tracking can be performed with respect to a change in frequency due to a change in the length of the vibrating stylus, and the marking device can be driven stably.

Further, a feedback signal whose phase has been corrected by the phase correction circuit is input to a non-vibration detecting circuit, and if it is determined by the feedback signal that the piezoelectric vibrator is not vibrating, an alarm signal is output from the non-vibration detecting circuit. Is output to the drive control circuit, and the drive control circuit inputs a cutoff signal to a multiplexer connected between the voltage controlled oscillator and the drive circuit, and cuts off the multiplexer to reduce the vibration of the piezoelectric vibrator. By stopping and inputting an alarm signal to the alarm device to generate an alarm, the ultrasonic marking device stops to prevent accidents such as breakage of the piezoelectric vibrator when vibration stops, and automatic operation Sometimes it can be stopped automatically.

[0007]

FIG. 1 is a block diagram of an ultrasonic marking apparatus according to an embodiment of the present invention. One electrode of a piezoelectric vibrator 1 is grounded, and the other electrode is connected to an output terminal of a drive circuit 2. The input terminal of the drive circuit 2 is connected to the output terminal of the voltage controlled oscillator 3, and the drive circuit 2 is connected to a current signal detection circuit 6 including a resistor 4 and a capacitor 5. The input terminal of the amplifier 7 is connected, the output terminal of the feedback amplifier 7 is connected to a phase correction circuit 8, the output terminal of the phase correction circuit 8 is connected to one input terminal of the phase comparator 9, and the voltage The output of the control oscillator 3 is connected to the other input terminal of the phase comparator 9,
The output terminal of the phase comparator 9 is connected to the input terminal of the low-pass filter 10, the output terminal of the low-pass filter 10 is connected to the input terminal of the voltage controlled oscillator 4, and the piezoelectric vibrator 1 is connected to the stylus of an ultrasonic marking device (not shown). Are connected.

[0008] In the ultrasonic marking apparatus of the present embodiment configured as described above, the output of the voltage controlled oscillator 3 is applied to the driving circuit 2.
, And the output of the drive circuit 2 is input to the piezoelectric vibrator 1 to vibrate the piezoelectric vibrator 1 to stylus (not shown).
And a feedback signal is detected by a current signal detector 6 from a current flowing from the drive circuit 4 to the piezoelectric vibrator 1, the feedback signal is amplified by a feedback amplifier 7, and the amplified feedback signal is phase corrected. The phase of the signal is corrected by the circuit 8, the output of the voltage-controlled oscillator 3 and the output of the voltage-controlled oscillator 3 are input to the phase comparator 9, and the phases are compared with each other. After removing the signal, the signal is input to the voltage-controlled oscillator 3 to control the phase of the output of the voltage-controlled oscillator 3 so that the change in the frequency due to the change in the length of the stylus vibrated by the piezoelectric vibrator 1 is prevented. Tracking can be performed stably, and the marking device can be driven stably.

FIG. 2 is a block diagram of an ultrasonic marking apparatus according to another embodiment of the present invention. 1 is a piezoelectric vibrator, 2 is a drive circuit, 3 is a voltage controlled oscillator, 6 is a resistor 4 and a capacitor 5 Current signal detection circuit, 7 is a feedback signal amplifier,
Reference numeral 8 denotes a phase correction circuit, 9 denotes a phase comparator, and 10 denotes a low-pass filter. These components are the same as those in the above-described embodiment, and a description thereof will not be repeated. 11 output terminals are connected,
A voltage controlled oscillator 3 is connected to the input terminal of the multiplexer 11.
The output terminal of the drive control circuit 12 is connected to the multiplexer 11, the drive signal circuit 13 is connected to one terminal of the drive control circuit 12, and the other terminal of the drive control circuit 12 is connected to the other terminal. The output terminal of the vibration detection circuit 14 is connected, the input terminal of the non-vibration detection circuit 14 is connected to the output terminal of the phase correction circuit 8, and the alarm device 15 is connected to the non-vibration detection circuit.

In the embodiment having the above-described configuration, the feedback signal whose phase has been corrected by the phase correction circuit 8 is used as the non-vibration detection circuit 1.
4, the feedback signal causes the piezoelectric vibrator 1
If it is determined that is not vibrating, the non-vibration detection circuit 1
4 outputs an alarm signal, and the alarm signal is input to the drive control circuit 12. The drive control circuit 12 inputs a cutoff signal to the multiplexer 11 connected between the voltage controlled oscillator 3 and the drive circuit 2, and The vibration of the piezoelectric vibrator 1 is interrupted to stop the vibration of the piezoelectric vibrator 1, and an alarm signal is input to the alarm device 15 to generate an alarm.
When the vibration is stopped, the ultrasonic marking device can be stopped in order to prevent an accident such as breakage of the piezoelectric vibrator 1 and automatically stopped during automatic operation.

In this embodiment, as described above, the stylus of the marking device is vibrated by the piezoelectric vibrator 1 and the change in the length of the stylus is automatically detected to stably vibrate the piezoelectric vibrator 1. Further, in order to prevent breakage of the piezoelectric vibrator 1 when the stylus becomes short and deviates from resonance of the piezoelectric vibrator 1 and no longer vibrates,
The output of the voltage controlled oscillator 3 can be automatically stopped.

[0012]

As described above, according to the ultrasonic marking apparatus of the present invention, the piezoelectric vibrator for driving the stylus can be driven stably, and the vibration of the piezoelectric substance when the stylus is shortened can be obtained. There is an advantage that the break of the piezoelectric vibrator can be prevented by automatically detecting the stop of the element.

[Brief description of the drawings]

FIG. 1 is a block diagram of an ultrasonic marking device according to an embodiment of the present invention.

FIG. 2 is a block diagram of an ultrasonic marking device according to another embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 piezoelectric vibrator 2 drive circuit 3 voltage controlled oscillator 4 resistor 5 capacitor 6 current signal detection circuit 7 feedback signal amplifier 8 phase correction circuit 9 phase comparator 10 low-pass filter 11 multiplexer 12 drive control circuit 13 drive signal circuit 14 non-vibration detection Circuit 15 Alarm

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Kazuyuki Funabashi 4-19-7 Kamata, Ota-ku, Tokyo Inside Ando Electric Co., Ltd.

Claims (2)

[Claims] In a marking device for engraving a character or a symbol on an object by vibrating a marking tool with a piezoelectric vibrator, a driving circuit for driving the piezoelectric vibrator and supplying high-frequency vibration power to the driving circuit. A voltage-controlled oscillator, a current signal detection circuit for detecting a current signal applied from the drive circuit to the piezoelectric vibrator, a feedback signal amplification circuit for amplifying an output of the current signal detection circuit, and a feedback signal amplification circuit. A phase correction circuit for correcting the phase of the output of the circuit, a phase comparator for comparing the phase of the output of the phase correction circuit with the phase of the output of the voltage controlled oscillator, and removing a high-frequency component of the output of the phase comparator. A low-pass filter for supplying a control voltage to the voltage-controlled oscillator. 2. A multiplexer is connected between the voltage controlled oscillator and the drive circuit, a drive control circuit for driving or stopping the multiplexer is connected to the multiplexer, and a drive signal circuit is connected to the drive control circuit. A non-vibration detection circuit detects an oscillation stop due to an abnormality or an overload of the piezoelectric vibrator from an output of the phase correction circuit, and inputs a non-vibration detection signal from the non-vibration detection circuit to the drive control circuit to generate the multiplexer. 2. The ultrasonic marking device according to claim 1, further comprising: stopping the operation, and inputting a non-vibration detection signal from the non-vibration signal detection circuit to an alarm device to activate the alarm device.