JPH02110364A - Method and apparatus for ultrasonic wave inspection - Google Patents

Abstract

PURPOSE:To simplify inspection using ultrasonic waves and to improve inspecting efficiency by hitting a body under inspection with an ultrasonic wave transmitting body for transmitting the ultrasonic waves, and detecting the input of the ultrasonic wave into the body under inspection and the reflected wave from the body under inspection during the time when the ultrasonic wave transmitting body is in close contact with the body under inspection. CONSTITUTION:In an ultrasonic wave transmitting body (hammer) 30, an ultra sonic wave transmitter-receiver 36 is provided at the hammer tip side from a hit detecting sensor 34. In the ultrasonic wave transmitter-receiver 36, a wave sending piece and a wave receiving piece are separately provided. The ultrasonic wave is inputted into a body under inspection through a tip part 31 of the hammer 30. The ultrasonic wave reflected from the body under inspection can be detected. Now, the body under test is hit with the hammer 30. During the time when the hammer 30 is in contact with the body under test, the input of the ultrasonic wave into the body under test and the reflected wave are detected. In this way, the body under inspection can be inspected by the ultra sonic wave without providing a contact medium between the contact under inspection and the hammer 30.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention involves injecting ultrasonic waves into an object to be inspected to apply ultrasonic vibrations, and detecting the ultrasonic waves reflected from inside the object to be inspected. The present invention relates to an ultrasonic inspection method and an ultrasonic inspection apparatus for detecting defects, etc.

[Conventional technology]

FIG. 10 shows an outline of a conventional ultrasonic inspection method.

As shown in FIG. 10, a probe 1 that transmits and receives ultrasonic waves
0 is brought into contact with one side surface of the object to be inspected 12, and is connected to a transmitter 14 that excites the probe 10 and a receiver 16 that detects and amplifies the electrical signal from the probe 10. The output signal of the receiving section 16 is input to an oscilloscope 18. Further, the oscilloscope 18 is configured to receive a sweep signal from a synchronization section 20 that sends a synchronization signal to the transmission section 14 .

When inspecting the object to be inspected 12, a high frequency impulse is generated in the transmitter 14 in synchronization with a synchronization signal generated by the synchronizer 20,
The probe 10 is excited to inject ultrasonic waves into the object 12 to be inspected. The ultrasonic waves incident on the object to be inspected 12 are reflected by the scratches 22 in the object to be inspected 12, the other end surface of the object to be inspected 12, etc., and are reflected by the probe 1.
Return to 0. The probe 10 detects the reflected ultrasonic waves, converts them into electrical signals, and sends them to the receiver 16 as detection signals.

FIG. 11(A) shows an example of a detection signal output by the probe 10, in which a is a transmitted pulse and b is a surface echo C reflected from the surface of the object to be inspected 12. d is a bottom echo reflected by the bottom surface of the object I2 to be inspected.

When the detection signal is input from the probe 10, the receiving section 16 detects and amplifies the detected signal as shown in FIG. 11(B), and sends it to the oscilloscope 18. By determining the time T from the surface echo to the detection of the flaw echo or bottom echo, the presence or absence of the flaw 22, the position of the flaw 22, and the thickness of the object to be inspected I2 can be obtained.

That is, if D is the distance from the surface on which the probe 10 is placed where a scratch echo or bottom echo occurs, then D-(TXv
)/2 ...----1----(1). Here, T is the time from detection of the surface echo to detection of the scratch echo or bottom echo, and V is the speed of sound.

In this way, in ultrasonic inspection, ultrasonic waves are incident on the object to be inspected from one side of the object to be inspected, and the ultrasonic waves reflected from the object are detected to determine whether or not there are internal defects in the object to be inspected. It measures the thickness and is widely used in both industrial and medical fields because it allows the internal state of the object to be inspected to be determined without destroying the object.

When ultrasonic waves are incident on the object to be inspected, if air exists between the ultrasonic probe 10 and the object to be inspected 12, most of the ultrasonic waves will be reflected by the surface of the object to be inspected 12. Since ultrasonic waves cannot be incident on the object to be inspected, the surface of the object to be inspected 12 may be coated with a couplant such as oil, water, grease, or petroleum jelly, or liquid may be placed between the ultrasonic probe and the object to be inspected. They also intervene.

[Problem to be solved by the invention]

As mentioned above, in the conventional ultrasonic inspection method, the surface of the object to be inspected 12 is coated with a couplant, the ultrasonic probe 1 is
Since the liquid is interposed between the test object 12 and the test object 12, the test object becomes dirty, and the test object must be washed and dried after the test is completed. Then, the object to be inspected 1
There was an inconvenience in that it was not possible to inspect the parts that were not coated with the couplant in step 2, and that it was not possible to inspect any part with a countersunk. Moreover, if the surface of the object 12 to be inspected is rough and has small irregularities (for example, when the surface is finished with paint), the probe 10 may be moved while being in contact with the object 12 to be inspected. If this happens, the surface of the object to be inspected 12 will be damaged (problems), and the tip of the probe 10 will wear out, making it impossible to use it for a long time.

The present invention has been made in order to eliminate the drawbacks of the prior art, and provides an ultrasonic inspection method that allows an object to be inspected to be inspected by ultrasonic waves without using a couplant, and a method for carrying out this ultrasonic inspection method. The purpose is to provide an ultrasonic inspection device for

Means for Solving Problem C] In order to achieve the above object, the ultrasonic inspection method according to the present invention includes the steps of: injecting ultrasonic waves into an object to be inspected, and detecting the ultrasonic waves reflected from the object to be inspected. In an ultrasonic inspection method for inspecting an object to be inspected, an ultrasonic transmitting body that transmits ultrasonic waves is collided with the object to be inspected, and while the ultrasonic transmitting body and the object to be inspected are in contact with each other, , is characterized in that ultrasonic waves are incident on the object to be inspected and reflected waves are detected.

Further, the ultrasonic inspection apparatus according to the present invention is an ultrasonic inspection apparatus that inspects the inspected object by injecting ultrasonic waves into the inspected object and detecting the ultrasonic waves reflected from the inspected object.
It is characterized by having a hammer that applies a striking force to the object to be inspected, and an ultrasonic transducer provided on the hammer.

[Effect]

When an object with a width of Wkm collides with the object to be inspected, for example, when the object is hit with a hammer, when the tip of the hammer comes into contact with the object to be inspected, the tip of the hammer and the surface of the object to be inspected will be They are elastically deformed and come into close contact with each other for a certain period of time.

Therefore, if ultrasonic waves are applied to the object to be inspected through the hammer while the two are in close contact and the reflected waves from the object are detected, a couplant can be inserted between the object to be inspected and the hammer. It becomes possible to inspect the object to be inspected using ultrasonic waves without having to do so.

In particular, if the hammer is made of a soft member that is easily elastically deformable, the adhesion between the hammer and the object to be inspected will be good.

This can be schematically explained as shown in FIG. That is, if the spring constant of the combined impact point of the object to be inspected and the hammer is k, then when the hammer 30 of tim collides with the object to be inspected at a speed V from a state where it is not in contact with the object to be inspected (8th
(A), (B)), the tip of the hammer and the surface of the object to be inspected are elastically deformed, and the hammer 30 moves by X in the direction of the object to be inspected from the position where it came into contact with the object to be inspected ( Figure 8 (C
)) After that, the hammer 30 receives a reaction force from the object to be inspected and is bounced away from the object to be inspected (Fig. 8(D), (
E)). The equation of motion at this time is as shown in equation (2) below.

m (d ” t / d L ”) + k x
-0---(2) Here, t is time.

Therefore, the moment when the hammer 30 hits the object to be inspected is 1=0.
, X=O, at tQ, (d x /
d t ) = V Sx = Q −−−−−−−
----(3) Therefore, if we solve equation (2) using equation (3) as a boundary condition, x=(V/ωo)Xsin(11t------m
−・・−−−(4) However, ω. =1T7TE.

When x<0, the object to be inspected and the hammer 30 are far apart, so the time T during which they are in contact can be calculated from equation (4) as T
= π/ω. =π(TFV7T −−−−−−−−−・
---1-・-(5). The force F acting between the hammer 30 and the object to be inspected is F=k x = (kV/ωo) sin (tl
o t-(6), and the acceleration A of the hammer 30 is
A = −V (1) o sjn ωo t ---
It can be obtained as -------(7).

Force F and acceleration A obtained from the above equations (6) and (7)
is the value when O≦L≦T, and at other times, FA=O. This is illustrated in FIG. 9. Therefore, the fact that the hammer is in contact with the object to be inspected can be known by detecting the reaction force from the object that the hammer receives and the acceleration of the hammer.

The force F determined by equation (6) can be detected by attaching a force detector having a piezoelectric element, piezoresistive element, strain gauge, or the like as a detection element to the tip of the hammer 30. Further, the acceleration A in equation (7) can be detected by attaching an acceleration pickup to an arbitrary position of the hammer 30.

By the way, by pressing the ultrasonic transmission medium against the object to be inspected, it is possible to bring the two into close contact with each other, but when the ultrasonic transmission medium collides with the object to be inspected as in the present invention, (a) ultrasonic waves The pressing force Fo of the transmission medium against the object to be inspected can be made very large.

(b) There is no need for a member to receive the reaction force of the pressing force F.

It has the advantage of

That is, the force F required for a hammer of quality i1m to reach speed ■ is d '' x / d t '' −F w / m --
−−−−−−1−−−From (8), F v = m v 7' t o−・−−(9) L
o is the time that the force Fν is acting on the hammer.

From equation (6), the maximum value of the collision force when a collision occurs at the speed of
-1] 2-7m Fv too.

−(K t o / T) F V −−−−−−−
---・-GO) T is the time of collision and contact, so it is very short. When T=0.01 seconds and to=1 second, F□8 is approximately 314 times the applied force Fv.

Therefore, a large contact force (pushing force) is achieved with a small acting force.
Fo can be obtained. Since the hammer, which is an ultrasonic transmitter, is pressed by the hammer's inertia force, there is no need for a reaction force receiver, and the device can be made smaller and lighter.

〔Example〕

Preferred embodiments of the ultrasonic inspection method and ultrasonic inspection apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram of an ultrasonic inspection apparatus for carrying out an ultrasonic inspection method according to the present invention.

In FIG. 1, the hammer 30 is fixed to the tip of a handle 32, the tip 31 is formed in the shape of a warhead by a relatively soft material that is elastically deformable, such as plastic, and has a force detector or an acceleration sensor in the middle. A hit detection sensor 34 such as an up-stroke is provided. Furthermore, the hammer 30 has
An ultrasonic transducer 36 is provided closer to the tip of the hammer than the impact detection sensor 34. The Fa sound wave transducer 36 has a wave transmitter and a wave receiver separately provided (both not shown), and transmits ultrasonic waves to an object to be inspected (not shown in FIG. 1) through the tip 31 of the hammer 30. It is designed to detect ultrasonic waves that are incident and reflected from the object to be inspected.

The impact detection sensor 34 is connected to the comparison circuit 3,
The comparison circuit 38 compares the detection signal f from the impact detection sensor 34 with a predetermined reference value, and provides a pulse generation command S to the pulse generation section 40 when the detection signal exceeds the reference value. The pulse generator 40 is connected to the transmitter of the ultrasonic transducer 36, and applies an excitation pulse P to the transmitter to generate ultrasonic waves.

Further, the wave receiver of the ultrasonic transducer 36 is connected to the detection circuit 44, and sends a detection signal R based on the detection of the ultrasonic waves reflected from the object to be inspected to the detection circuit 44. A time measurement circuit 46 connected to the output side of the detection circuit 44 is connected to the output side of the detection circuit 44.
When a detection signal is received from 4, the zero time measuring circuit 46 calculates a time T, which will be described later.
The 0 judgment circuit 52, which is connected to a recording section 50 such as a recording chart, and to which a judgment circuit 52 is connected, receives the time T from the time measurement circuit 46, and judges the presence or absence of scratches on the object to be inspected and whether it is good or bad. Then, the results are output to a display section 54 such as a lamp and a recording section 56.

The operation of the embodiment configured as described above is as follows.

Holding the grip part (not shown) of the handle 32 shown in FIG.
When the tip 31 of the hammer 30 collides with the object to be inspected and a striking force is applied to the object, the tip 31 receives a reaction force from the object. This reaction force reaches its peak as the time elapses after the tip portion 31 starts contacting the object to be inspected. At this time, since the tip portion 31 is made of a relatively soft material that deforms elastically, such as plastic, it deforms elastically and comes into close contact with the surface of the object 12 to be inspected, as shown in FIG. 2(A). do.

Thereafter, the hammer 30 is bounced back by the reaction force from the object to be inspected 12, and the reaction force from the object to be inspected 12 decreases and moves away from the object to be inspected 12. At this time, the impact detection sensor 34
In response to the reaction force from the object to be inspected 12, a detection signal f as shown in FIG. 2(B) is sent to the comparison circuit 38. Comparison circuit 38
compares the detection signal f from the impact detection sensor 34 with a preset reference value r. This reference value r0 is determined by the spring constant (rigidity) of the hammer tip 31 and the object to be inspected 12, and the set value can be changed freely.

On the third day of the comparison circuit, when the detection signal f exceeds the reference value 10, it generates a rectangular pulse as shown in FIG. Outputs command S. This pulse generation command S is input to the pulse generation section 40. Then, as shown in FIG. 2(D), the pulse generator 40 sends an excitation pulse P to the transmitter of the ultrasonic transducer 36 at the rising edge of the pulse generation command S.
Generates ultrasonic waves.

The ultrasonic waves from the transmitter of the ultrasonic transducer 36 are transmitted to the hammer 3
The light enters the object to be inspected 12 that is in close contact with the tip 31 through the tip 31 of the laser beam, and is reflected by the object to be inspected 12 . The receiver of the ultrasonic transducer 36 receives the reflected wave from the object to be inspected 12, converts it into an electrical signal, and sends the detected signal R to the detection circuit 44 (FIG. 2(E)). detects and amplifies the detection signal R from the ultrasonic transducer 36, and inputs it to the time measurement circuit 46 as a detection signal (see Fig. 2 (F)).
)).

When the surface finish code b is input from the detection circuit 44, the time measuring circuit 46 starts counting clock pulses (see FIG. 2 (1)) output from a clock circuit (not shown). ), as shown in Figure 2 (H), the counting is finished by inputting the next detection signal D (flaw echo C or bottom echo d), and the time T from the surface echo b to the next echo is calculated. Output. This time T is displayed on the display section 48, printed out by the recording section 50, and inputted into the judgment circuit 52.The zero judgment circuit 52 compares it with a preset reference value T, and compares the measured time with a preset reference value T. T is the reference value T
If it is the same as 0, the inspected object 12 is considered to be normal, and a blue lamp, for example, on the display section 54 is turned on, and the recording section 56
records.

If the time T is smaller than the reference value T, it is assumed that a scratch echo C reflected from a scratch inside the inspected object 12 has been detected, and the red lamp on the display section 54 is turned on and the recording section 56 is Record.

In this way, in the embodiment, the hammer 30, which is an ultrasonic transmitting body that transmits ultrasonic waves, is brought into close contact with the object to be inspected 12 by colliding with the object to be inspected 12, and while the two are in close contact, measurement using the ultrasonic waves is performed. Therefore, there is no need for pre-treatment such as coating the surface of the object 12 to be inspected with a couplant unlike in the past. In particular, since the tip 31 of the hammer 30 is made of a soft material such as elastically deformable plastic, the object 12 to be inspected is not damaged and the adhesion between the tip 31 and the object 12 to be inspected is improved. It can be done. Therefore, not only can any part of the object 12 to be inspected be quickly inspected without pre-processing, but also the object 12 to be inspected is not contaminated, cleaning, etc. can be omitted, and the efficiency of the inspection is improved.

FIG. 3 shows an embodiment in which the hammer is not driven manually but electrically.

In FIG. 3, the hammer 30 includes a head portion 58 having a strike detection sensor 34 and an ultrasonic transducer 36, and a hammer weight 62 connected to the head portion 58 via a shaft 60.
It consists of A hammer drive coil 64 is provided around the hammer weight 62, and a return spring 70 is provided between the upper surface of a coil frame 66 that covers the drive coil 64 and a spring receiver 68 formed on the upper part of the hammer weight 62. is compressed and urges the hammer 30 upward in the figure.

On the other hand, a comparison circuit 38 connected to the impact detection sensor 34
The output signal of the pulse generator 40 and the hammer drive controller 7
2.

Hammer drive control section 72 outputs a control signal to hammer drive circuit 74 that supplies drive current i to hammer drive coil 64 . Further, the ultrasonic transducer 36 uses a probe that can be used for both transmission and reception, and the pulse generator 4
0 and the detection circuit 44 for connection. Note that the circuit on the detection side is the same as the embodiment shown in FIG.

In this embodiment, the hammer drive control section 72 provides an on signal to the hammer drive circuit 74 at a predetermined period. Hammer drive circuit 74 receives the control signal and supplies drive current 1 to hammer drive coil 64 . When the hammer drive coil 64 is excited, the hammer weight 62 of the hammer 30 is attracted by the magnetic force generated by the hammer drive coil 64, moves downward in FIG. 3 against the biasing force of the return spring 70, and the tip portion 31 collides with the object to be inspected and applies a striking force to the object to be inspected.

This impact force is detected by the impact detection sensor 34 as described above, and a detection signal f is sent to the comparison circuit 38.

As described above, the comparison circuit 38 converts the detection signal f into the reference value f.
0, and outputs a pulse generation command S shown in FIG. 2(C) to the pulse generation section 40, hammer drive control section 72, and switch control section (not shown). The switch control section sets the switch 42 to the pulse generation section 40 side at the rising edge of the pulse generation command S, thereby connecting the pulse generation section to the ultrasonic transducer 36. Further, the pulse generator 40 applies an excitation pulse P to the ultrasonic transducer 36 at the rising edge of the pulse generation command S. When the pulse generator 40 sends out the excitation pulse P, the switch 42 is switched to the detection circuit 44 side, and the ultrasonic transducer 36 and the detection circuit 44 are connected. Then, the time T is measured as described above.

On the other hand, upon receiving the pulse generation command S, the hammer drive control section 72 sends an off signal to the hammer drive circuit 74 at the rising edge of the pulse generation command S, thereby stopping the supply of the drive current i to the hammer drive coil 64. The hammer 30 has a hammer drive coil 64
When the supply of drive current i to the hammer drive coil 64 is stopped, the attraction force by the hammer drive coil 64 disappears, and the hammer drive coil 64 moves upward due to the biasing force of the return spring 70 and moves away from the object to be inspected. Then, the hammer 30 is moved downward by the next excitation of the hammer drive coil 64, and the above operation is repeated thereafter.

In this embodiment, since the hammer 30 is electrically driven, inspection labor can be reduced and inspection can be automated. In addition, also in this embodiment, a wave transmitter and a wave receiver which are separate bodies may be used.

FIG. 4 shows another embodiment of the method for driving the hammer 30. In this embodiment, a return coil 76 is provided in place of the return spring 70 of the embodiment shown in FIG. The hammer drive coil 64 and the return coil 76 are connected to the hammer drive circuit 74 via a switch 78. The other configurations are the same as in FIG. 3.

In the method of driving the hammer 30 of this embodiment, the drive control section 72 switches the switch 78 to the hammer drive coil 64 side and outputs an ON command to the hammer drive circuit 74. This results in
The hammer drive circuit 74 applies a drive current iI to the hammer drive coil 64 to excite it. Then, the hammer drive control section 72
When the hammer 30 is attracted by the hammer drive coil 64 and collides with the object to be inspected, and the pulse generation command S shown in FIG. 2(C) is input, the hammer is driven by the rising edge of the pulse generation command S. An off command is output to the circuit 74, the switch 78 is switched to the return coil 76 side, and an on command is given to the hammer drive circuit 74 again at the fall of the pulse generation command S. The hammer drive circuit 74 supplies one return drive current to the return coil 76 to excite it, and the return coil 76 attracts the hammer weight 62 of the hammer 30 and pulls it upward, pulling the tip 31 away from the object to be inspected. vinegar.

Note that the hammer drive circuit may be provided separately for driving and for returning.

Furthermore, in the embodiment shown in FIG. 3, a case has been described in which the ultrasonic transducer 36 used for both transmission and reception is switched and connected to the pulse generator 40 and the detection circuit 44 using the changeover switch 42, but in the embodiment shown in FIG. It is also possible to connect the wires in this manner and omit the changeover switch 42. Furthermore, as shown in FIG. 10, wave transmission and delivery may be performed separately.

FIG. 6 shows an embodiment in which the impact detection sensor 34 is omitted. The detection signal R of the ultrasonic transducer 36 is input to the comparator circuit 38 via a low-pass filter 82, and the bypass filter 8
The signal is inputted to the detection circuit 44 via 4.

The ultrasonic receiver configuring the ultrasonic transducer 36 generally uses a piezoelectric element such as crystal or zinc oxide (ZnO). Therefore, when the hammer 30 collides with the object to be inspected and receives a reaction force from the object, that force acts on the ultrasonic receiver. Therefore, the ultrasonic transducer 36 outputs a detection signal as shown by the curve r in FIG. 7(A), which corresponds to the output from the impact detection sensor 34. Therefore, when the detection signal R from the ultrasonic transducer 36 is passed through the low-pass filter 82, the striking force detection signal f has a waveform as shown in FIG. 7(B).
' is obtained, and the comparison circuit 38 compares this detection signal f' with a reference value r0' to output a pulse generation command S.

Then, when the detection signal r'> base 1 (If.'), when an excitation pulse P is given to the ultrasonic transducer 36 to generate an ultrasonic wave, the detection signal R of the ultrasonic transducer 36 is Figure 7 (
As shown in A), the echoes a, b, c, and d are superimposed on the detection signal r. Therefore, when this detection signal R is passed through the bypass filter 84, a detection signal R' consisting only of echoes from the object to be inspected as shown in FIG. 7(C) is obtained, and the time T is measured in the same manner as in the previous embodiment. be able to.

〔Effect of the invention〕

As explained above (according to the present invention), an ultrasonic transmitter that transmits ultrasonic waves collides with an object to be inspected, and while the ultrasonic transmitter and the object to be inspected are in close contact with each other, the object to be inspected is Since ultrasonic waves are incident on the body and reflected waves from the object to be inspected are detected, no couplant is required, and ultrasonic inspections can be performed easily and the efficiency of the inspection can be improved.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of an embodiment of an ultrasonic inspection apparatus for carrying out the ultrasonic inspection method according to the present invention, Fig. 2 is a time chart explaining the operation of the embodiment, and Fig. 3 is an illustration of an electric hammer. FIG. 4 is an explanatory diagram of another embodiment of the hammer driving method. FIG. 5 is an explanatory diagram of an embodiment using an ultrasonic transducer that functions as a transmitter and receiver. 7 is an explanatory diagram of an embodiment in which no impact detection sensor is used, FIG. 7 is an explanatory diagram of the detection signal of the ultrasonic transducer of the embodiment shown in FIG. 6, and FIG. 8 is an explanatory diagram of the ultrasonic inspection method of the present invention. A schematic diagram explaining the principle, Figure 9 is an illustration of changes in force and acceleration acting on the hammer in the principle shown in Figure 8, Figure 10 is an illustration of the conventional ultrasonic inspection method, Figure 11 1 is a diagram explaining the principle of an ultrasonic inspection method. 30 ・-=-hammer (ultrasonic transmitter), 31-・-
Tip portion, 34--One hit detection sensor, 36--Ultrasonic transducer. 3rd o ha tsuma 31 first store Shimaku 34 ゛ ne te cane entrance 7 nsa 36: si Shu: L receiving shibo; C Shin 2v4 fig. FA) (B) (C) (D) (E ) Figure θ Now F, 1(t) Figure Figure Figure Figure Figure

Claims (2)

[Claims] (1) In an ultrasonic inspection method in which an ultrasonic wave is incident on an object to be inspected and the ultrasonic wave reflected from the object is detected to inspect the object, the ultrasonic wave is transmitted to the object to be inspected. An ultrasonic device characterized in that an ultrasonic transmitting body is collided with the object to be inspected, and while the ultrasonic transmitting body is in contact with the object to be inspected, the ultrasonic wave is incident on the object to be inspected and the reflected wave is detected. Sonic testing method. (2) In an ultrasonic inspection device that inspects the object by injecting ultrasonic waves into the object to be inspected and detecting the ultrasonic waves reflected from the object, applying a striking force to the object to be inspected. An ultrasonic inspection device comprising a hammer and an ultrasonic transducer provided on the hammer.