JP3089893B2 - AE sensor inspection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AE sensor (Acoust) for detecting a vibration fixed on a solid and propagating through the solid.
The present invention relates to an inspection apparatus for an AE sensor for inspecting the quality of an IC emission sensor.

[0002]

2. Description of the Related Art Conventionally, this type of apparatus is disclosed in
As shown in JP-A-2-251658, an AE sensor for vibration is fixed to a solid at a position facing an AE sensor for detection for detecting vibration propagating through the solid, and the AE sensor for vibration is fixed to the AE sensor for vibration. AE for excitation by supplying drive pulse train signal
The sensor is excited, and the vibration propagating through the excitation is converted into an electric signal by the AE sensor for detection, and the quality of the AE sensor for detection is determined based on the amplitude, count number, number of events, rise time, and the like of the electric signal. Is determined.

[0003]

However, in the above-mentioned conventional apparatus, the characteristics of the converted electric signal change depending on the mounting method and the mounting position of the vibration AE sensor. Variations occur in amplitude, count number, event number, rise time, etc.
The quality of the sensor could not be determined accurately. SUMMARY OF THE INVENTION The present invention has been made to address the above-described problem, and an object of the present invention is to provide an AE sensor inspection apparatus capable of accurately determining the quality of an AE sensor for detection with a simple configuration.

[0004]

In order to achieve the above object, a structural feature of the present invention is to generate a driving pulse train signal having one of positive and negative polarities connected to an AE sensor and to supply the driving pulse train signal to the AE sensor. And a determination circuit connected to the AE sensor and determining the quality of the AE sensor based on a signal of the other positive or negative polarity among the response signals from the AE sensor.

[0005]

In the present invention configured as described above, when the drive pulse generation circuit generates a drive pulse train signal of positive (or negative) polarity, the AE sensor and the solid are excited by the drive pulse train signal. You. With this excitation, the AE sensor generates a response signal that changes between positive and negative, and the determination circuit determines the quality of the AE sensor based on the negative (or positive) polarity signal of the response signals. As described above, according to the present invention, the drive pulse train signal is applied to the AE sensor for detecting the vibration propagating through the solid, and the quality of the AE sensor is determined based on the response signal from the sensor. As described above, there is no variation in the response signal due to the attachment of the vibration AE sensor, and the quality of the AE sensor is always accurately determined. Also,
According to the present invention, a special AE such as a vibration AE sensor is used.
Since no sensor is required, the entire apparatus can be simply configured.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an entire AE sensor 10 inspection apparatus according to the embodiment.

The AE sensor 10 is constituted by a piezoelectric element, and is attached to the upper surface of a pressure punch 20 as a solid which propagates vibration in the present invention via a grease 11 in order to improve adhesion. The pressurizing punch 20 presses and fixes a work (not shown), and in an ordinary use state, the AE sensor 10 detects presence or absence of breakage of the work by an ultrasonic wave transmitted through the pressurizing punch 20. .

The inspection apparatus includes a drive pulse generation circuit 30 and a determination circuit 40 both connected to the AE sensor 10 via a conductor L1. The drive pulse generating circuit 30 includes a pulse oscillator 31 and a drive amplifier 32. The pulse oscillator 31 outputs a negative drive pulse train signal while the pulse signal output from the one-shot circuit 51 is at a high level. The pulse width of the drive pulse train signal is set to, for example, about 10 μs, and the cycle is set to, for example, 100 ms.
Set to about. The drive amplifier 32 amplifies the drive pulse train signal from the pulse oscillator 31 and outputs the signal to the AE sensor 10. The one-shot circuit 51 rises in synchronization with the ON operation of the start switch 52, outputs a pulse signal that changes to a low level after maintaining a high level for a predetermined time (for example, set to several hundred ms to several s).

The decision circuit 40 includes a forward diode 41.
And an analog comparator 43 having a positive input connected to the conductor L1 via the amplifier 42. The negative input of the analog comparator 43 is connected to a potentiometer 44 for generating a positive reference voltage Vref, and the comparator 43 generates a pulse signal when the voltage from the amplifier 42 exceeds the reference voltage Vref. The output of the analog comparator 43 is connected to the clock input of the counter 45, and the counter 45 is reset in synchronization with the rise of the pulse signal from the one-shot circuit 51, and its count value is reset by the pulse signal from the analog comparator 43. Is counted up.
The output of the counter 45 is connected to a digital comparator 46. The comparator 46 compares the output value of the counter 45 with a predetermined value when the pulse signal from the one-shot circuit 51 falls, and displays the comparison result on a display. Output to 47. The display 47 indicates that the AE sensor 10 is normal when the output value of the counter 45 is larger than a predetermined value based on the comparison result, and otherwise indicates that the AE sensor 10 is abnormal. .

Next, the operation of the embodiment configured as described above will be described. When the start switch 52 is operated, the one-shot circuit 51 generates a pulse signal of a predetermined width, and the pulse oscillator 31 generates a negative driving pulse train as shown in FIG. 2 over a period in which the pulse signal is at a high level. The signal is output to the AE sensor 10 via the drive amplifier 32. As a result, the AE sensor 10 and the pressure punch 20 are excited by the respective drive pulse signals, and the sensor 10 outputs a positive / negative vibration waveform signal as shown in FIG. 2 as a response signal to the excitation. Only the positive part of the vibration waveform signal is supplied to the amplifier 42 through the diode 41, and the amplifier 42 amplifies the vibration waveform signal and supplies the amplified signal to the comparator 43. The comparator 43 outputs a pulse signal to the counter 45 every time the instantaneous value of the vibration waveform signal exceeds the reference voltage Vref. Since the counter 45 is reset to “0” when the start switch 52 is operated, the counter 45 counts and outputs the number of pulse signals from the analog comparator 43 while the pulse signal output from the one-shot circuit 51 is at a high level. Then, the digital comparator 46 compares the count value representing the number of pulse signals with a predetermined value and outputs the comparison result to the display 47.

If the AE sensor 10 is normal and outputs a proper response signal, the instantaneous value of the signal exceeds the reference voltage Vref more than a predetermined number of times. Therefore, in this case, since the count value to be compared becomes larger than the predetermined value, the display 47 indicates that the AE sensor 10 is normal. On the other hand, if an abnormality occurs in the AE sensor 10 and only an inappropriate response signal is output, the number of times that the instantaneous value of the signal exceeds the reference voltage Vref is equal to or less than a predetermined value. Therefore, in this case, the count value to be compared is equal to or less than the predetermined value, and the display 47 indicates that the AE sensor is abnormal.

As can be understood from the above description of operation, according to the above embodiment, a negative drive pulse train signal is applied to the AE sensor 10 and the AE sensor 10 is controlled based on a positive response signal from the sensor 10. Judge good or bad,
AE sensor 1 without special AE sensor for vibration
Since 0 can be inspected, the problem of the variation of the response signal due to the attachment of the AE sensor for vibration is solved, and the quality of the AE sensor 10 is inspected accurately. Also,
Since the AE sensor for excitation is omitted, the configuration of the entire inspection apparatus is simplified.

In the above embodiment, the drive pulse train signal of the negative polarity is applied to the AE sensor 10, and the quality of the sensor 10 is determined based on the positive response signal from the sensor 10. Conversely, a positive drive pulse train signal may be provided to the AE sensor 10 and the quality of the sensor 10 may be determined based on a negative response signal from the AE sensor 10. In this case, the pulse oscillator 31 generates a drive pulse train signal of a positive polarity, connects the diode 41 in the reverse direction, and the analog comparator 43 inputs the signal from the amplifier 42 at the negative input and also at the positive input. What is necessary is just to input the negative reference voltage -Vref.

In the above embodiment, the quality of the AE sensor 10 is checked based on the number of times the response signal exceeds the reference voltage Vref. However, the amplitude of the response signal, the number of events, the rise time, etc. are taken into consideration. The quality of the AE sensor 10 may be inspected.

[Brief description of the drawings]

FIG. 1 is a block diagram of an inspection device for an AE sensor according to an embodiment of the present invention.

FIG. 2 is a signal waveform diagram of each part of the block diagram.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... AE sensor, 20 ... Pressing punch, 30 ... Drive pulse generation circuit, 31 ... Pulse oscillator, 40 ... Determination circuit, 4
3 ... analog comparator, 44 ... potentiometer, 45 ...
Counter, 46: Digital comparator, 47: Display.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-62-251658 (JP, A) JP-A-2-296159 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01R 31/00 G01H 17/00

Claims (1)

(57) [Claims] 1. An inspection apparatus for an AE sensor, which is fixed to a solid and detects vibrations propagating through the solid, wherein the AE sensor is connected to the AE sensor to generate a drive pulse train signal having one of positive and negative polarities. A drive pulse generation circuit to be supplied to the sensor; and a determination circuit connected to the AE sensor and determining the acceptability of the AE sensor based on a signal having the other positive or negative polarity among response signals from the AE sensor. An inspection apparatus for an AE sensor, characterized in that: