JPH06118070A - Exciting method and exciting device - Google Patents

Abstract

PURPOSE:To prevent the generation of an abnormal excitation such as double hammering by emitting a solid projectile toward a material to be measured from below it, and raising it by inertial force just before collision. CONSTITUTION:When a solenoid valve control circuit 34 opens a solenoid valve 33 for a determined time, the air from a compressed air generating means 31 is regulated in pressure by a regulator 32, passed through the solenoid valve 33, regulated in flow rate by a speed controller 35, and sent to an emission part 36. An exciting projectile 40 starts to be raised by this air. In the course of rising, the circuit 34 closes the solenoid valve 33. The exciting projectile 40 is further raised by the supplied air, and after passed through a through-hole 38, it is raised only by inertial force, emitted from an injection hole 39, and collided with a material 41 to be measured. After collision, the exciting projectile 40 is naturally fallen by the repulsive force of the material 41 and the gravity. Since the exciting projectile 40 is thus raised by the inertial force and naturally fallen after collision, double hammering at the collision with the material 41 can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibrating method and apparatus for generating vibration on an object to be measured.

[0002]

2. Description of the Related Art Defects such as cracks, cavities, and dents in parts of machines and products can cause serious danger due to breakage of the parts. Therefore, it is preferable that components having defects such as cracks, cavities, and dents can be detected and removed in a component production line before assembly of a machine or a product.

Further, even in a component having no defects, for example, the graphite contained in cast iron is locally spheroidized,
If the part is harder than the other parts, the hard part may crack or chip during use of this part. Therefore, it is desirable to be able to detect in the manufacturing line the parts in which there are locally different hardnesses.

By the way, as a nondestructive inspection method for detecting a defect and for locating a position, conventionally, a method by reflection of an ultrasonic wave, a detection method by a sound when a crack is generated by AE (acoustic emission), and an observation by a CCD camera are used. Method, X-ray photography method, color check method, etc. are known.

On the other hand, there is no conventional method for detecting whether or not there are portions having different hardnesses in an object to be measured while keeping the original shape of the object to be measured.

However, each of the conventional nondestructive inspection defect detection methods described above has the following handling problems.

That is, for example, the ultrasonic flaw detection method is a method of detecting a defect by bringing it into contact with an object to be measured, and it is possible to measure only a portion to which a sensor is applied due to the straightness of the ultrasonic wave, which is caused by a mismatch in a sensor connection surface. Waveforms that are visible due to reflections and slight angle differences are different, making discrimination difficult.

Further, in the case of the AE method, it can be measured only by the contact method as in the ultrasonic flaw detection method and by the progressive crack. On the other hand, in the case of a progressive type, the measurement is performed while expanding the crack.

In addition, the observation method using a CCD camera has the drawback of disturbing the determination even if there are spots or patterns other than defects such as cracks and dents, and cavities called "su" cannot be detected in castings and the like. .

Further, the X-ray photography method is effective because it can be visually observed directly, but it is difficult to observe the X-ray dose for an object having a thin thickness or an object having a thick thickness, which is troublesome. In addition, it is not suitable for 100% inspection of measured objects and not suitable for inspection on a production line.

Further, even if there is a locally different hardness in the object to be measured, that is, if there is a different hardness, or if foreign matter with a different hardness is mixed, there is no conventional method for detecting this, and in the manufacturing line, It has not been possible in the past to remove such parts.

Therefore, the applicant of the present application has previously filed a method and apparatus for detecting defects and different hardness portions without the above defects (Japanese Patent Application Nos. 1-259183 and 1-2).
5184, Japanese Patent Application No. 2-86035, etc.).

In the method proposed above, the vibration of the measured object generated by vibrating the measured object is picked up in a non-contact manner, converted into an electric signal, and the electric signal is spectrally analyzed. It is a method for detecting the presence and size of defects and different hardness portions. This method was born from the following research results.

That is, as a result of the research by the inventor of the present invention, when the vibration of the measured object that is excited is picked up and the spectrum is analyzed, the peak of the spectrum is found at the natural frequency position determined according to the shape of the measured object. Appeared and
It has been found that when there is a defect and / or a different hardness portion (including foreign matter), the peak of each corresponding spectrum is divided into two.

This can be considered as follows. That is, a standing wave vibration (longitudinal vibration = longitudinal wave) peculiar to the object to be measured is generated by the vibration, and the spectrum standing at the natural frequency position can be observed due to the vibration. And
When there are no defects or different hardness portions, the spectrum can be observed as one peak 11, 12, 13 and the like appearing at each of the natural frequency positions, as shown in FIG. 2A.

However, defects (cracks) and "su"
If there are cavities, etc.), vibration cannot be transmitted to this defect, and a detour propagation path is created, and the energy of vibration is divided into the energy of the above-mentioned unique vibration and the energy of vibration passing through the bypass. Since the propagation path of the vibration passing through the bypass is longer than that of the natural vibration, the frequency at which the spectrum stands is lower than the spectrum of the natural vibration. Therefore, as shown in FIG. 2B, another spectrum peak 14, 15, 16 appears on the side of which the frequency is lower than the spectrum peaks 11, 12, 13 at the natural frequency position, and each spectrum has two peaks. Break up.

Further, the propagation speed of vibration differs depending on the hardness of the substance, and the higher the hardness, the faster the propagation speed. For this reason, when a portion having a different hardness locally exists, the propagation velocity of the vibration at that portion is different from the propagation velocity of the natural vibration, and the energy of the vibration is the energy of the natural vibration and that of the vibration passing through the portion having the different hardness. Vibration energy is separated from energy. In this case, if a portion harder than other parts is unevenly distributed in the DUT, it appears separately in the fundamental natural vibration spectrum and the spectrum on the higher frequency side, and similarly in the DUT. If a portion softer than the portion is unevenly distributed, the spectrum of the fundamental natural vibration and the spectrum on the frequency side lower than that are observed separately.

In this way, it is possible to detect whether or not there is a defect and a different hardness portion in the object to be measured depending on whether or not the spectrum of the natural vibration can be observed separately.

The inventor has confirmed that the frequency difference between the two divided spectra corresponds to the defect in the propagation direction of the standing wave vibration or the length of the different hardness portion. Therefore, when there is a defect or a different hardness portion, the length of the defect and the different hardness portion in the propagation direction of the standing wave vibration can be known by obtaining the frequency difference between the two divided peaks of the spectrum. The size (volume) or shape of the defect or the like can be detected from the length of the defect or the like in the propagation direction.

When the length of the vibration wave such as a defect in the propagation direction is very small, the peak of the spectrum of the vibration wave is not divided into two and the Q value of the spectrum becomes small. It is considered that this is because the spectrum of the natural vibration wave and the spectrum of the vibration wave due to the presence of cracks are observed as being combined without being separated due to insufficient frequency resolution of the arithmetic device. Therefore, by detecting this Q value, it is possible to determine the presence and size of defects and different hardness portions.

In the above-described defect determining device,
As an oscillating device, an impulse hammer method is used to apply an impact to an object to be measured to generate vibration.
Conventionally, as the vibration method using this impulse hammer, vibration by a human hand, or a drive mechanism that uses a cam mechanism to swing the weight by the principle of a pendulum so that the weight is separated from the object to be measured after an impact A mechanism or the like is used.

[0022]

By the way, the applicant is
As a result of the research, it was found that in the nondestructive inspection method described above, it is important to apply a single vibration when the object to be measured is excited.

That is, like the double hammering and the triple hammering, the vibration is applied twice or more, or the vibration member is stuck to the object to be measured (actually, the vibration is finely repeated. ), And so to speak, a spectrum is generated due to abnormal excitation.

For example, when the object to be measured has no defect or the like and double hammering or the like does not occur,
As shown in FIG. 3A, a waveform of only spectrum 21 in which side lobes do not occur, but when double hammering occurs, as shown in FIG. 3B, the time interval of double hammering, that is, the first and second times Of the spectrum 2 at the frequency interval (1 / T) according to the time interval T of excitation of
The side lobe spectrum 60 due to this double hammering appears around 1.

Therefore, when an abnormal vibration state such as double hammering occurs, the spectrum 60 cannot be distinguished from the separation of the spectrum peculiar to the object to be measured caused by a defect or the like, and the defect is substantially present. It becomes impossible to detect the part with different hardness. Alternatively, even if there is no defect or the like, the spectrum due to abnormal vibration is erroneously detected as due to the defect or the like.

However, in the above-described conventional vibration method, that is, the vibration by the human hand and the method of swinging the weight by the principle of the pendulum using the cam mechanism, the abnormal vibration such as double hammering is avoided. It was difficult to do so.

In view of the above points, it is an object of the present invention to provide a vibrating method and apparatus which do not cause abnormal vibration such as double hammering.

[0028]

In order to solve the above-mentioned problems, a vibrating method according to the present invention ejects a solid bullet toward the object to be measured from below the object to be measured, and measures the solid bullet to be measured. A method of vibrating an object to be measured by causing it to collide with an object, characterized in that the solid bullet is raised by an inertial force at least immediately before collision with the object to be measured.

[0029]

According to the present invention having the above-described structure, a solid bullet rising from below due to inertial force collides with the object to be measured, and the object to be measured is vibrated. Since the solid bullet rises due to the inertial force, it does not naturally fall due to the repulsive force from the measured object due to the collision and the gravity, and double hammering does not occur.

[0030]

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 of an embodiment of a vibrating device of this example. In this example, compressed air is used as a compressed fluid, and a vibrating bullet of a solid is raised by the compressed air and collides with an object to be measured from below. In this example, the measured object is vibrated.

Reference numeral 31 is a compressed air generating means, for example, 7 to
Generates compressed air of 10 kgf / cm ² . A regulator 32 controls the compressed air from the generating means 31 to an appropriate pressure. Reference numeral 33 is a solenoid valve, which is opened / closed by a control signal from a solenoid valve control circuit 34. A speed controller 35 adjusts the flow rate of compressed air.

Reference numeral 36 is a vibrating bullet ejection unit. This injection part 3
A solid vibrating bullet 40 having a circular cross section is put in the inside 6. In addition, a conduit portion 37 having an inner diameter substantially equal to the outer diameter of the exciting bullet 40 is formed in the ejecting portion 36, and the exciting bullet 40 is ejected from the ejecting portion 36 through the conduit portion 37. It has become so. Then, a through hole 38 that connects the inside of the conduit portion 37 and the outside atmosphere is formed at an intermediate position of the passage of the vibration bullet 40 of the conduit portion 37.

In this case, the injection part 36 has its conduit part 37.
Is placed almost vertically, and the ejection port 39 is installed so as to face upward.
Are made to collide with the measured object 41 from below the measured object 41 placed on the measurement table 42. In addition, in this example, the ejection port 39 is arranged in a position close to the object to be measured so that the vibrating bullet 40 can surely collide with an appropriate portion of the object 41 to be measured.

The operation of the vibrating apparatus of this example constructed as above will be described. That is, the solenoid valve control circuit 34 opens the solenoid valve 33 for a predetermined time. Then, the compressed air from the compressed air generating means 31 is supplied to the regulator 32.
After being adjusted to an appropriate pressure by, it is sent to the speed controller 35 via the solenoid valve 33. Then, the flow rate of the compressed air is adjusted by the speed controller 35, and then the compressed air is sent to the injection unit 36. The oscillating bullet 40 contained in the ejection part 36 starts to rise due to the compressed air sent in.

The solenoid valve control circuit 34 includes a vibrating bullet 4
The solenoid valve 33 is closed while 0 is rising in the conduit portion 37. However, due to the compressed air sent in, the vibration bullet 4
0 goes up further. Then, the vibrating bullet 40 is inserted into the through hole 3
When the pressure rises above 8, the compressed air is discharged to the outside air through the through hole 38. Therefore, the vibrating bullet 40 continues to rise only by the inertial force thereafter and is ejected from the ejection port 39.
It collides with the DUT 41. Since the oscillating bullet 40 has risen due to the inertial force, the vibrating bullet 40 naturally falls due to the repulsive force from the measured object 41 due to the collision with the measured object 41 and the gravity.

As described above, the vibrating bullet 40 rises due to the inertial force, is ejected from the ejecting section 36 and collides with the object 41 to be measured,
Since it naturally falls due to the repulsive force and gravity, unnecessary force is not applied and double hammering at the time of collision of the DUT 41 can be prevented.

The vibration of the DUT vibrated by the collision of the vibrating bullet 40 is picked up by a vibration sensor 43 such as a microphone and converted into an electric signal, and the electric signal is supplied to a defect detection and judgment device 44. The defect detection determination as described above is performed.

Pressure of compressed air, speed controller 3
The flow rate at 5 and the opening / closing time of the solenoid valve are adjusted in advance to appropriate values so that double hammering or the like does not occur. And after adjustment, by fixing to the adjusted value,
It is possible to constantly vibrate with stable vibration energy.

In the above example, the compressed air sent to the injection portion 36 through the through hole 38 is discharged to the outside air, but instead of discharging to the atmosphere, the compressed air is sucked. May be. Further, the fluid used as the squeezing fluid is not limited to air as in the above example, but may be another gas such as nitrogen or a liquid such as water. Further, the conduit portion 37 of the injection portion 36 does not need to be vertically planted,
The vibration bullet 40 may be made to collide with the object to be measured 41 from diagonally below.

Further, the above example is an example in which the compressed fluid is used for firing and raising the oscillating bullet, but as the means for firing and raising the oscillating bullet, a spring or other means is used. It can also be used. For example, in the case of using a spring, the initial velocity may be determined so that the vibrating bullet hits the object to be measured so that it will rise due to inertial force.

In order to facilitate understanding of the present invention,
As a technical field for vibrating an object to be measured, the non-destructive inspection method proposed by the applicant to vibrate the object to be measured, picks up the vibration component, and judges defects etc. was explained. However, it goes without saying that the vibration method and apparatus of the present invention are applied not only to vibration of the object to be measured in this nondestructive inspection but also to various uses.

[0042]

As described above, according to the present invention, when a solid vibrating bullet is collided with the object to be vibrated and the object is vibrated, only the inertial force of the vibrating bullet causes the object to be measured. Since it was made to rise from below, after the collision with the object to be measured, the oscillating bullet naturally falls due to the repulsive force from the object to be measured and gravity, and abnormal vibration such as double hammering is caused. It is possible to perform vibration without causing it.

Further, according to the present invention, it is possible to easily and stably excite regardless of the shape, weight, etc. of the object to be vibrated.

[Brief description of drawings]

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

FIG. 2 is a diagram showing spectra for explaining the previously proposed defect detection method.

FIG. 3 is a diagram showing a spectrum analysis waveform when normal vibration is applied and when double hammering occurs.

[Explanation of symbols]

 31 Compressed Air Generating Means 32 Regulator 33 Solenoid Valve 34 Solenoid Valve Control Circuit 35 Speed Controller 36 Vibratory Ammunition Injection Section 37 Conduit Section 38 Through Hole 39 Ejection Port 40 Solid Vibration Ammunition

Claims (3)

[Claims] 1. A method of vibrating an object to be measured by ejecting a solid bullet from the lower side of the object to be measured toward the object to be measured and causing the solid bullet to collide with the object to be measured. A vibrating method characterized in that the solid bullet is raised by an inertial force immediately before it collides with an object to be measured. 2. An ejecting section for ejecting a solid bullet toward the object to be measured from below the object to be measured, and means for imparting a rising force to the solid bullet in order to eject from the object by at least the ejecting section, Immediately before the collision with the object to be measured, the solid bullet is lifted toward the object to be measured by inertial force. 3. An injection unit, which is provided with a conduit section for guiding the solid bullet toward the measured object, ejects the solid bullet toward the measured object from below the measured object, and generates compressed fluid. Means, an on-off valve for sending the squeezed fluid from the generating means to the injection part in order to raise the solid bullet inside the conduit part, and the conduit part provided in the injection part. A vibrating device comprising: an opening for allowing the compressed fluid perforated in the middle portion to flow out from the inside of the conduit portion.