JPH06335084A - Ultrasonic oscillator capable of monitoring oscillation frequency - Google Patents

Abstract

PURPOSE:To provide an ultrasonic oscillator for automatically stopping the drive of a vibrator when the resonance frequency of a load such as a horm to be driven by the vibrator gets out of the automatic frequency adjust range of an oscillation part. CONSTITUTION:An oscillation part 1 outputs an excited signal while matching the frequency of an excited signal for generating ultrasonic waves with the frequency of a feedback signal. This device is provided with an amplification part 2 for jetting out the ultrasonic waves by oscillating a vibrator 5 while amplifying this excited signal and passing it through a matching part 3, feedback signal pickup part 4 for detecting the resonance frequency of the driving target of the vibrator and feeding it back to the oscillation part as the feedback signal, and frequency monitor circuit 6 for deciding whether the frequency of the feedback signal is set within a previously set allowable value or not, stopping the supply of an output from the oscillation part when the frequency gets out of the allowable value and stopping the oscillation of the vibrator. When stopping the supply of the output from the oscillation part, the frequency monitor circuit generates an alarm by using an alarm circuit 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic oscillator used in an ultrasonic welder and an ultrasonic cleaning machine.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram showing a conventional example of this type of ultrasonic oscillator. The oscillator 71 oscillates a signal for ultrasonic wave generation while keeping the output frequency constant so as to match the frequency of the feedback signal provided. The amplifier 72 amplifies the signal from the oscillator 71 and outputs it to the matching unit 73. The matching unit 73 matches the output of the amplification unit 72 with the subsequent circuit, and drives the vibrator 75 to drive the vibrator 7.
The ultrasonic wave is emitted from 5. Return signal pickup unit 7
Reference numeral 4 picks up the resonance frequency of the drive target (example: horn) of the vibrator 75 as a feedback signal and outputs it as the feedback signal.

[0003]

The above-described conventional ultrasonic oscillator is used as follows in an ultrasonic cleaning machine in which a horn is immersed in a liquid and ultrasonic waves are emitted from the vibrator to the horn for cleaning. There was a problem.

(1) As the erosion of the tip of the horn progresses, the resonance frequency of the horn rises and goes out of the frequency automatic adjustment (automatic tracking) range of the oscillator.

(2) When an abnormality such as a crack occurs in the horn, the temperature rises abnormally and the resonance frequency decreases, which falls outside the frequency automatic adjustment range of the oscillator.

When these things occur, the oscillating section operates at a frequency that does not match the resonance frequency, and the mismatch causes the heat generation and damage of the transistor, leading to the failure of the circuit and the like.

In view of the above problems, it is an object of the present invention to provide an ultrasonic oscillator which automatically stops its operation when the resonance frequency of the horn is out of the frequency automatic adjustment range of the oscillator.

[0008]

An ultrasonic oscillator according to the present invention includes an oscillating section for outputting an excitation signal while making the frequency of an excitation signal for generating an ultrasonic wave equal to the frequency of a feedback signal, and an excitation signal. An ultrasonic oscillator comprising: an amplification excitation unit that amplifies the oscillator to excite the oscillator to emit an ultrasonic wave; and a feedback signal pickup unit that detects the resonance frequency of the drive target of the oscillator and returns it to the oscillation unit as a feedback signal. A frequency monitoring circuit for determining whether or not the frequency of the feedback signal is within a preset allowable value, and stopping the excitation of the oscillator when the frequency is not within the preset allowable value.

Further, it is preferable that the frequency monitoring circuit stops the supply of the output from the oscillating section to stop the excitation of the vibrator, and further when the supply of the output from the oscillating section is stopped. It is also preferable to include an alarm circuit equipped with an alarm indicator or alarm for generating an alarm.

[0010]

When the frequency of the feedback signal is within the allowable value, the frequency monitoring circuit considers it to be normal and continues its operation. However, if the frequency of the feedback signal exceeds the permissible value, it is considered that an abnormality has occurred, and the excitation of the oscillator is stopped by stopping the supply of output from the oscillator, etc. The operation is automatically stopped. Further, if an alarm display device or alarm device for issuing an alarm is provided, the abnormality can be more effectively communicated when the supply of the output from the oscillator is stopped.

[0011]

Embodiments of the present invention will now be described with reference to the drawings. 1 is a block diagram showing an embodiment of an ultrasonic oscillator of the present invention, FIG. 2 is a block diagram showing in detail an amplifying section of the embodiment of FIG. 1, and FIG. 3 is a detail of a frequency monitoring circuit of the embodiment of FIG. It is a block diagram shown in. The oscillating unit 1 generates an excitation signal for generating ultrasonic waves (eg, excitation signal initial value 19.5k.
Hz), but the frequency of the output oscillates so as to match the frequency of the applied feedback signal. Amplifier 2
Is composed of an input circuit 21, a preamplifier 22, and a power amplifier 23. The input circuit 21 is composed of a relay, a switching transistor, or the like. When the switching signal SW is inactive (for example, low level), the signal from the oscillator 1 is passed to the preamplifier 22, and when the switching signal SW is active. , Blocks the passage of signals from the oscillator 1. The preamplifier 22 and the power amplifier 23 amplify the signal from the input circuit 21 and output it to the matching unit 3.

The matching section 3 matches the output of the amplification section 2 with the vibrator 5, and drives the vibrator 5 to emit ultrasonic waves. The feedback signal pickup unit 4 (for example, Mitsuyoshi bridge) detects the resonance frequency of the drive target (example: horn) of the oscillator 5 and outputs it as a feedback signal to the oscillation unit 1 and the frequency monitoring circuit 6.

The frequency monitoring circuit 6 includes a filter 61, an amplifier 62, an fv converter 63, comparators 64 and 65, an OR.
The circuit 66. The feedback signal is applied to the fv converter 63 via the filter 61 and the amplifier 62, and the fv converter 63 outputs a voltage proportional to the frequency of the feedback signal. Each of the comparators 64 and 65 has an upper limit frequency (example: 2
0 kHz) and a lower limit frequency (for example, 19 kHz) are applied, and when the output of the fv converter 63 reaches the applied comparison voltage, the output is set to a high level. The OR circuit 66 activates the switching signal SW (high level) when either of the comparators 64 and 65 outputs a high level output. When the switching signal SW becomes active, the alarm circuit 7 lights up a light emitting diode or the like or generates an alarm sound.

Therefore, when this ultrasonic oscillator is used in, for example, an ultrasonic cleaning device, erosion progresses and the horn becomes shorter, so that the resonance frequency is lowered and goes out of the frequency automatic adjustment (automatic tracking) range of the ultrasonic oscillator. Then, the ultrasonic oscillator immediately stops the oscillation and generates an alarm, so that the ultrasonic cleaning machine can be safely operated without being damaged.

[0015]

According to the present invention, by including the frequency monitoring circuit as described above, when the frequency of the feedback signal is within the allowable value, it is regarded as normal and the operation is continued. However, if the frequency of the feedback signal exceeds the allowable value, it is considered that an abnormality has occurred, and the excitation of the vibrator is stopped, so the operation at the time of abnormality is automatically stopped and the member is destroyed. Can be prevented. Further, if an alarm display device or alarm device for issuing an alarm is provided, the abnormality can be more effectively communicated when the supply of the output from the oscillator is stopped.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an ultrasonic oscillator of the present invention.

FIG. 2 is a block diagram showing in detail an amplification unit of the embodiment of FIG.

FIG. 3 is a block diagram showing in detail the frequency monitoring circuit of the embodiment of FIG.

FIG. 4 is a block diagram showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 oscillating unit 2 amplifying unit 3 matching unit 4 feedback signal pickup unit 5 oscillator 6 frequency monitoring circuit 7 alarm circuit 21 input circuit 22 preamplifier 23 power amplifier 61 filter 62 amplifier 63 fv converter 64, 65 comparator 66 OR circuit

Claims (3)

[Claims] 1. An oscillation section for outputting an excitation signal and an oscillation section for amplifying the excitation signal to excite an oscillator to emit an ultrasonic wave while matching the frequency of the excitation signal for generating the ultrasonic wave with the frequency of the feedback signal. In an ultrasonic oscillator comprising an amplification excitation unit to be driven, and a feedback signal pickup unit that detects a resonance frequency of an object to be driven of the vibrator and feeds it back to the oscillation unit as a feedback signal, the frequency of the feedback signal is a preset allowable value. An ultrasonic oscillator, comprising: a frequency monitoring circuit for determining whether or not it is within the allowable range, and stopping the excitation of the vibrator when it is not within the allowable range. 2. The ultrasonic oscillator according to claim 1, wherein the frequency monitoring circuit stops the supply of the output from the oscillating unit to stop the excitation of the vibrator. 3. The frequency monitoring circuit according to claim 1, further comprising an alarm circuit including an alarm indicator or alarm for generating an alarm when the supply of the output from the oscillator is stopped. Sound wave oscillator.