JPH07270384A - Product passage inspection device - Google Patents

Abstract

PURPOSE:To provide a simple passage inspection device capable of accurately discriminating whether residual matter such as core sand is present in the hollow passage provided to a product. CONSTITUTION:An FFT analyser 7 measuring the volume of the hollow part provided in a cast product 10 and a comparing and judging means 8 comparing the volume measured by the analyser with that of the hollow part of a cast product being a comparison standard to judge the quality of the product are provided. A sonic wave is emitted into the hollow passage of the cast product 10 by the transmitter 4 arranged at one end of the hollow passage and the sonic wave passing through the hollow passage and exiting from the other end thereof is received by a receiver 5 and the frequency spectrum of the signal from the receiver 5 is analyzed by the FFT (fast Fourier transform) analyser 7 to detect the change of the volume of the hollow passage and the volume of the hollow passage is compared with that of the hollow passage of the standard product to judge the quality of the product.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a passage inspection device for inspecting a product having a hollow passage for a penetration state of the passage.

[0002]

2. Description of the Related Art Products having bent hollow passages and through holes,
For example, when casting a product such as an intake manifold which is an engine part of an automobile or a water jacket provided in an intake pipe, core sand is used to form the hollow passage or the through hole. This core sand is made by casting a cast product, then removing the core sand with a well-known knockout machine, and if the core sand is difficult to remove only by this process, heat the product further to remove the core sand. Is burned to collapse and removed from the through holes.

However, when the core sand is disintegrated and removed, a part of the core sand may not be completely collapsed and may remain attached to the hollow passage of the cast product or the inner wall of the through hole. This can occur as the shape of the hollow passage becomes more complicated. If such core sand is incorporated into the product without being removed, it will cause fatal damage to the engine, for example, if it is like an intake manifold of a car engine part or a water jacket of an intake pipe. It will be. Therefore, in such a cast product, after the completion of the cast product, it is necessary to closely inspect whether core sand remains in the hollow passage.

Therefore, as an apparatus for performing such an inspection, conventionally, a fluid is introduced into a hollow passage of a cast product, and the passage state of the fluid is examined to examine whether or not a residue is present in the hollow passage. There is a device to do it.
There are both gas and liquid as the fluid to be used,
As the one using gas, for example, Shoukaisho 62-77
No. 6483, and the device described in Japanese Utility Model Laid-Open No. 59-148166, which uses a liquid, is known.

FIG. 8 shows a basic structure of a passage inspection device using gas. An air introduction pipe 34 is attached to one opening 32 of a casting product 30 having a hollow portion 31 therein.
An air pressure sensor 35 is arranged in the other opening 33,
In the inspection, air having a constant pressure is introduced from the nozzle of the air introduction pipe 34 from the opening 32 side. At this time, when the core sand remains inside the hollow portion 31 of the cast product 30 at the positions indicated by Z _{1 to} Z ₃ and partially or completely blocks the hollow passage. , The other opening side 33
Since the air pressure of is lower than that of a normal product in which there is no residue, the penetration state inside the hollow passage 31 can be inspected by the measurement value from the air pressure sensor 35.

FIG. 9 is a block diagram of an apparatus using water as a fluid. High pressure water is introduced from a high pressure water tank 47 through a pressure supply pipe 48 through an opening 42 at one end of a cast product 40. It has become. And the other opening 4
3 and 44 are respectively provided with detection means 45 and 46 for detecting the presence / absence of fluid, and it is confirmed that the pressure water introduced into the hollow passage 41 flows out from the openings 43 and 44, and the hollow passage 41 is penetrated. It is to check the condition.

In the case where the fluid is introduced as in the above-mentioned prior art and the penetration state of the passage is inspected in the flowing state, the fluid pressure source for introducing the fluid or the fluid is introduced into the opening. It is unavoidable that the device becomes large and complicated, such as the need for a sealing mechanism to do so. In addition, the reliability of the device is reduced due to the occurrence of defective seals,
Alternatively, even if the introduced pressure of the fluid slightly fluctuates, the inspection result may be different, or the fluid resistance may not be uniform depending on the adhered state of the residual sand in the hollow passage, and Z in FIG.
_As shown in ₃ , there was also a problem with detection accuracy, such as core sand sticking to the corners of the cast product and not being detected in some cases.

In addition to an inspection device using a fluid, a steel ball is passed through the hollow passage of a cast product and the inside of the hollow passage is inspected in the passage state, and a light source is provided at one end opening of the hollow passage. There is also a method of irradiating the inside of the passage with light and observing the degree of light leakage at the other end side of the passage to inspect the inside penetration state. If the cross-sectional area of the steel ball changes or the cross-section is not a circle, the steel ball will pass through even if residual sand adheres if the passage of the projected area of the steel ball is secured There is a problem that the detection accuracy depends on the product.

Further, in the case of using light, there are many practical problems such as requiring the skill of an operator and not having a constant inspection criterion.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the prior art, and detects a change in the volume of a hollow passage of a product without using a medium such as liquid or gas. Thus, it is possible to inspect the penetration state inside the passage with high accuracy even with a cast product having a hollow passage having a complicated shape with a simple device, and the operation is simple and the inspection can be performed in a short time. An object is to provide a passage inspection device capable of performing

[0011]

According to a first aspect of the present invention, there is provided a passage inspection device for a product having a hollow passage, which comprises a volume measuring means for measuring a volume of a hollow portion of the passage, and The present invention is characterized in that a comparison determination means is provided for comparing the volume measured by the volume measuring means with the volume of the hollow portion of the product passage serving as a comparison reference and determining the quality of the product.

According to a second aspect of the present invention, there is provided a passage inspection device for a product having a hollow passage, wherein the generated sound source is installed at one end of the passage and emits sound waves in the passage, and the passage. Of a sound wave that has passed through the passage, a wave receiver that is installed on the other end side of the sound wave that receives the sound wave that has passed through the passage, a frequency analyzer that analyzes the frequency spectrum of the acoustic signal received by the wave receiver, It is characterized in that a comparison determination means is provided for comparing the power spectrum with the power spectrum of the passage of the product serving as a comparison reference to determine the quality of the product.

According to a third aspect of the present invention, there is provided a passage inspection device for a product having a hollow passage, wherein the generated sound source is installed at one end of the passage and generates a sound wave having a frequency of a predetermined width. A wave receiver that receives sound waves that have passed through the passage installed on the other end of the passage, and a frequency analyzer that analyzes the frequency spectrum of the acoustic signal received by the wave receiver,
It is characterized in that a judging means for judging whether the product is good or bad is provided by comparing the spectrum of the sound wave that has passed through the passage with the spectrum of the sound wave that has passed through the passage of the product serving as a comparison reference.

[0014]

In the invention of claim 1, the volume of the hollow portion of the hollow passage of the product which is the inspection object is measured, and the volume is defined as the volume of the reference hollow portion of the product which has been measured in advance. Compare. The presence of residue in the hollow passages of the product will reduce the volume of the hollow portion of the hollow passages. Therefore, if the volume of the hollow part measured for the test object is smaller than that of the reference product, it can be judged that there is some residue inside, and the quality of the product is judged. be able to.

According to the second aspect of the present invention, a sound wave of a predetermined frequency is emitted from one end of the hollow passage of the product as the inspection object, and a sound wave exiting the other end of the passage is received. The received signal is frequency analyzed by a frequency analyzer. When the power spectrum of a predetermined frequency shows a smaller value than that of a normal product as a comparison reference, the volume of the hollow part of the passage is reduced, in other words, some residue is present in the passage. It can be determined that there is, and the quality of the product can be determined.

According to the third aspect of the invention, a sound wave having a frequency of a predetermined width is passed through the hollow passage of the product, and the spectrum of the passed sound wave is compared with that of the reference product to detect the volume change in the passage. To do. Since a frequency of a predetermined width is input into the hollow passage, it is possible to compensate for the decrease in the volume of the hollow portion that is difficult to capture depending on the frequency with another frequency, and it is possible to accurately determine the quality of the product. .

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram of a passage inspection apparatus according to an embodiment of the present invention. In the figure, 10 is a cast product which is a test object and has a hollow passage inside, and shows an intake manifold which is an automobile engine part as a specific example. The hollow passage inspection apparatus 1 emits sound toward a sound source 2 for generating sound, an amplifier 3 for amplifying an acoustic signal generated by the sound source 2, and an inner passage of an intake manifold 10 which is an inspection object. A wave transmitter 4 arranged at one end of the passage, a sound collecting wave receiver 5 arranged at the other end of the intake manifold 10, an amplifier 6 for amplifying an acoustic signal collected by the wave receiver 5, Comparing with the reference product based on the peak level value of the power (frequency characteristic per unit time) obtained by the FFT analyzer (fast Fourier transform analyzer) 7 and the FFT analyzer for performing the waveform and frequency analysis of the obtained acoustic signal. It comprises a comparison / determination unit 8 for determining the quality of the intake manifold.

In this embodiment, four sound sources are used.
Ultrasonic waves of 0 KHz are used. Therefore, the generated sound source is an oscillator having a frequency of 40 KHz, and the transmitter 3 is a vibrator operating at 40 KHz. The operation of this device is as follows.
The wave transmitter 4 is operated to emit a sound wave of 40 KHz from the wave transmitter 4 into the hollow passage of the intake manifold 10 which is the inspection object. On the other hand, at the other end of the hollow passage, the sound wave coming out through the hollow passage is received by the wave receiver 5, and this acoustic signal is amplified by the amplifier 6, and then the FFT analyzer 7
To analyze the waveform and frequency spectrum of the received acoustic signal.

Prior to the inspection of the product to be inspected by this inspection apparatus, a preliminary test carried out using this inspection apparatus will be described. FIG. 2 and FIG. 3 respectively utilize this device and show no residual sand in the hollow passage of the intake manifold, that is, a hollow passage having a hole opening degree of 100% and a hollow passage having a volume of 70%, respectively. Is closed with residual sand, that is, the results of testing the hollow passages with a hole opening degree of 30%. For each, 40 KHz in the passage
Sound is transmitted and the acoustic signal of the sound collected at the other end is FFT
It is a graph which shows the waveform and power spectrum (frequency characteristic) of a waveform analysis result by an analyzer.

Looking at the frequency spectrum of the sound wave passing through the passage of 100% in-hole opening in which no residual sand exists in the passage of FIG. 2 (b), a power peak appears at 40 KHz which is the same as the transmission frequency. ing. On the other hand, in the case of the intake manifold having the aperture ratio of 30% in FIG. 3, as shown in the power spectrum of FIG.
As in the case of 100% opening of the passage in FIG. 2B, a peak of power appears at 40 KHz which is the same as the transmission frequency, but the peak level value is −100% of opening.
It is -31.1 dB with respect to 4.8 dB.
The waveform of the sound wave shown in FIG.
Similar to the case of (a), it indicates that the frequency is the same as the transmission frequency and the frequency is not changed and the amplitude is attenuated at a constant rate.

Regarding the relationship between the openness of the hollow passage and the level value of the peak of the power spectrum, similar test results have been obtained for the test bodies having other opennesses. The peak value is the openness of the hollow passage. That is, it was confirmed that the volume changes depending on the volume of the hollow portion of the hollow passage. In the passage inspection apparatus of the present invention, when a sound wave having a constant frequency emitted in the hollow passage of the object to be inspected, which is obtained by the preliminary test, exits the passage, the power spectrum of the sound wave is emitted. This is applied to the passage inspection, paying attention to the fact that only the power of the frequency of the sound wave changes according to the opening degree of the passage, in other words, the hollow volume of the passage.

FIG. 4 is a characteristic graph showing the relationship between the peak level value and the opening degree of the passage, that is, the volume of the hollow portion of the passage. This characteristic graph is similar to the above-mentioned FIG. 2 and FIG.
In the intake manifold that measured the volume of the hollow passage,
Similarly, it is a result obtained by a preliminary test performed by using the apparatus of FIG. 1 using a test body in which the core sand is filled and which is filled with core sand. By using the data of the characteristic graph of FIG. 4, the opening degree of the hollow passage, that is, the volume of the hollow portion of the passage can be measured from the peak level value of the power spectrum.

In the inspection actually performed on the product to be inspected, the frequency of attenuation depends on the clogging position. Therefore, the frequency of the sound wave to be transmitted is not only a single frequency (40 KHz in the embodiment), but all frequencies in a certain band range from the sound source. Outgoing,
The signal received by the wave receiver is frequency-analyzed by the FFT analyzer. Then, by comparing the peak value at a predetermined frequency of the master work (normal product), the clogging position and the aperture ratio (clogging condition) are inspected to identify the defective product.

As described above, the device of this embodiment detects the decrease in the volume of the hollow portion of the passage due to the presence of the residue in the hollow passage by using the sound wave, and thereby,
The quality of the product is inspected by grasping the penetration state of the hollow passage of the device under test, and the presence or absence of the residue can be accurately detected, and the quality of the product can be inspected accurately. It should be noted that although 40 KHz ultrasonic waves are used as sound waves in the above-described embodiment, they do not necessarily have to be in the ultrasonic wave frequency band, and those in the audible frequency band can also be used. Further, the inspection object is not limited to the hollow passage of the cast product, but can be applied to the inspection of through holes of various parts and the passage of the structure. Then, the frequency of the sound wave to be used can be appropriately selected in consideration of the shape and size of the passage of the inspection object, the required accuracy of inspection, and the like.

FIG. 5 shows another embodiment of the passage inspection apparatus of the present invention. The inspection object 21 of this embodiment includes a body portion 21a having a hollow passage and a plurality of branch passages 21b.
Structures with are used. The path inspection device 20 of the present embodiment is basically an FFT analyzer 22, a preamplifier 23, a speaker 24, a microphone 25, and an amplifier 2.
6 and a data analysis device 27.

In the present embodiment, the sound wave sent to the inspection object 21 is generated by the speaker 24 by amplifying the output from the oscillator (not shown) for generating a sound source incorporated in the FFT analyzer 22 by the preamplifier 23. I am trying to let you. The sound wave sent to the end of the body portion 21a of the inspection object 21 is collected by the microphone 24 arranged at one end of the branch passage 21b. The collected acoustic signal is amplified by the amplifier 26 and sent to the FFT analyzer 22 as measurement data. The FFT analyzer 22 analyzes the waveform and the power spectrum as in the embodiment shown in FIG.

In the present embodiment, the power spectrum data obtained by the FFT analyzer 22 is further processed to inspect the closed state of the passage in the inspection object. The power spectrum data obtained by the FFT analyzer 22 is sent to the data analysis device 27. Here, first, the power spectrum data is taken in by the personal computer 27a, and this power spectrum data is sent to the workstation 27b for data analysis and determination of the quality of the inspection object.

At the workstation 27b, cepstrum analysis (inverse Fourier transform of logarithmic data of the power spectrum) is performed based on the power spectrum data, and the result is taken out as a product of the spectrum envelope and the fine spectrum structure. As an example, FIG. 6 is a graph showing a state in which a power spectrum (a) obtained by using a sound wave having a band width of 0 to 20 KHz as a sound source is decomposed into an envelope (b) and a fine structure (c). Is represented.

The inspection of the inspection object 21 is carried out by comparing the fine structure data of the power spectrum obtained from the acoustic signal of the sound wave passing through the inspection object with the data of the master good work as a reference. If the spectrum fine structure data of the inspection object is the same as that of the master work, it can be determined that there is no object that blocks the passage of the inspection object, and if any object remains in the passage, It is different from the masterwork spectral fine structure. And, the greater the proportion of blocked passages, the greater the difference in spectral fine structure than that of the masterwork. In this embodiment, paying attention to this point, the comparison of spectra is used to judge the quality of a product.

The contrast between the inspection object having the fine spectral structure and the masterwork can be quantitatively grasped as data by calculating the correlation coefficient of the fine spectral structure data of both. The correlation coefficient R between the spectrum fine structure of the inspection object and the spectrum fine structure of the masterwork can be obtained by the following equation.

[0031]

[Equation 1]

Here, X _i : Spectral data of masterwork Y _i : Spectral data of inspected object n: Number of data X _AVE : Average value of X _i Y _AVE : Average value of Y _i FIG. Regarding the relationship between the correlation coefficient R between the spectral fine structure of the target object and the spectral fine structure of the masterwork and the change in the aperture ratio of the hollow passage of the test subject, the same structure as the test subject whose aperture ratio is known in advance It represents the result of the examination using the test body of.

As shown in FIG. 7, it can be seen that the correlation coefficient of the spectral fine structure changes depending on the change in the aperture ratio which indicates the closed state of the hollow passage or the change in volume. Therefore,
In the actual inspection of the inspection object, the correlation coefficient between the spectrum fine structure of the master work and the spectrum fine structure of the inspection object is calculated, and the relationship between the aperture ratio and the correlation coefficient of FIG. 7 obtained in advance is calculated. By using the formula, it is possible to know the aperture ratio (volume change ratio based on the master work) of the inspection object. As a result, for example, when the inspection target is selected based on the constant opening ratio of the passage, it is possible to determine and select based on the predetermined value of the correlation coefficient.

In the present embodiment, the sound wave having a predetermined band width is input into the inspection object having the hollow passage, and the spectrum of the sound wave changing in the process of passing through the hollow passage is analyzed. Even if there is a change in the volume of the hollow passage that is difficult to catch depending on the frequency, this can be compensated for by the information from the sound waves of other frequencies, and the accuracy of determining the quality of the product can be improved.

Further, the waveforms of the sound waves of the inspection object and the reference product are compared by calculating the correlation coefficient of the spectrum, and the correlation between the correlation coefficient and the opening ratio of the hollow passage is used to open the opening ratio (volume change). ), The calculation processing by the computer is facilitated, and it becomes possible to arbitrarily set the criterion of the quality of the product as a numerical value.

[0036]

According to the first aspect of the present invention, the residual amount in the hollow passage is checked based on the comparison between the volume of the hollow portion of the cast product and the volume of the hollow portion of the cast product, which is the reference for the inspection of the cast product. Since it is performed by detecting the presence or absence of an object, the residue can be detected accurately without being affected by the shape of the residue or the position where it is present, and even if it has a complicated shape it does not miss detection. Therefore, it becomes possible to accurately inspect the quality of the product.

According to the second aspect of the present invention, basically, the passage inspection device can be constituted by the sound source, the wave receiver, and the signal analyzer. It is simple and does not require a special medium to reduce the size of the device. Further, the operation of the apparatus does not involve complicated operation, does not require special skill, and the inspection time is extremely short, and the inspection work efficiency can be improved. And the inspection device of the present invention,
The inspection can be easily automated by combining with an automatic transfer device such as a conveyor for the object to be inspected.

According to the third aspect of the invention, a sound wave having a frequency of a predetermined width is sent as a sound source into the passage of the product, and the volume of the hollow portion of the passage is determined based on the waveform of the power spectrum of the sound wave passing through this passage. Since the quality of the product is judged by detecting the decrease, even if there is a decrease in the volume of the hollow part that is difficult to catch depending on the frequency, it is compensated for by other frequencies, so the product can be judged with high accuracy. You can

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a path inspection device according to the present invention.

FIG. 2 is a received wave waveform diagram (a) and a power spectrum diagram (b) with a hole aperture of 100%.

FIG. 3 is a waveform diagram (a) and a power spectrum diagram (b) of a received wave with a hole aperture of 30%.

FIG. 4 is a diagram showing an example of a characteristic diagram showing a relationship between a hole opening degree and a power peak level value.

FIG. 5 is a configuration diagram showing another embodiment of the passage inspection apparatus according to the present invention.

FIG. 6 is a diagram showing a power spectrum and a cepstrum analysis result thereof.

FIG. 7 is a graph showing the aperture ratio dependence of the correlation coefficient of the fine structure.

FIG. 8 is a basic configuration diagram of a conventional technique using gas.

FIG. 9 is a basic configuration diagram of a conventional technique using a liquid.

[Explanation of symbols]

1, 20 Passage inspection device 2 Generated sound source 3 Amplifier 4, 24 Transmitter (speaker) 5, 25 Receiver (microphone) 6, 23, 26 Amplifier 7, 22 FFT analyzer 8 Comparator / discriminator 10 Intake manifold 21, 30 , 40 inspection object 27 data analysis device 34 air supply pipe 35 air pressure sensor Z _{1 to} Z ₃ residual sand 45, 46 pressure water detection means 47 pressure water tank 48 pressure water supply pipe

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hidenori Nagai 1 Toyota-cho, Toyota-shi, Aichi Toyota Automobile Co., Ltd. (72) Inventor Kenji Yaso 2-9-32 Nakamachi, Musashino-shi, Tokyo Yokogawa Electric Incorporated (72) Inventor Keiichi Kubota 2 Toyota-cho, Toyota-shi, Aichi Toyotamax Co., Ltd.

Claims (3)

[Claims] 1. An apparatus for inspecting a product having a hollow passage, the volume measuring means for measuring a volume of a hollow portion of the passage, and the product passage serving as a reference for comparison with the volume measured by the volume measuring means. A device for inspecting a passage for a product, characterized by comprising a comparison / determination means for determining the quality of the product by comparing the volume of the hollow part of the product. 2. A device for inspecting a product having a hollow passage, wherein a generated sound source installed at one end of the passage to emit a sound wave in the passage and the passage installed at the other end of the passage. A wave receiver that receives a sound wave that has passed, a frequency analyzer that analyzes the frequency spectrum of an acoustic signal received by the wave receiver, and a passage of a product that serves as a comparison reference for the power spectrum of the sound wave that has passed through the passage. The device for inspecting a passage for a product, comprising: a comparison / determination unit that determines the quality of the product by comparing the power spectrum of the product. 3. A passage inspection apparatus for a product having a hollow passage, wherein a sound source for generating a sound wave having a frequency of a predetermined width is installed at one end of the passage, and the passage is installed at the other end of the passage. The wave receiver that receives the sound wave that has passed through, the frequency analyzer that analyzes the frequency spectrum of the acoustic signal received by the wave receiver, and the spectrum of the sound wave that has passed through the passage passes through the passage of the reference product. A device for inspecting a passage of a product, characterized by comprising a judging means for judging the quality of the product by comparing with the spectrum of the sound wave.