JP2000235022A - Inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely judge whether a seal member is good or not, by a simple work process, without affecting a structure equipped with the seal member, in the case of an inspection device suitably used to inspect whether a gasket or an O-ring is not left uninstalled. SOLUTION: This inspection device is equipped with two members 1, 2 fastened to each other with a seal member 3 interposed between them, a vibration exciting means 11 for exciting the vibration of one member 2 of them, vibration detecting means 12, 13 for detecting vibration produced in the other member 1 of the two members 1, 2 resulting from the vibration of the one member 2 caused by the vibration exciting means 11, and a transforming means 14 for outputting the frequency characteristic of the vibration of the other member 1 obtained by Fourier-transforming vibration signals of the other member 1 detected by the vibration detecting means 12, 13, and whether the seal member 3 is good or bad is judged by comparing the frequency characteristic of the vibration of the other member 1 outputted from the transforming means 14 with a reference characteristic.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection apparatus for inspecting the quality of a seal member interposed between two members.
In particular, the present invention relates to an inspection apparatus suitable for use in inspecting a gasket or an O-ring forgot to be assembled.

[0002]

2. Description of the Related Art In the case of a structure formed by connecting a plurality of members, a sealing member such as a gasket or an O-ring is interposed between the two members to make the structure air-tight or liquid-tight. Is equipped. For example, the engine body is configured by connecting a cylinder head on a cylinder block, but between such a cylinder block and the cylinder head, the gas inside the engine is prevented from leaking.
Gaskets are interposed. Also, at the end of such an engine body, parts such as an oil pump case containing an oil pump for pressurizing the engine oil and a bracket for attaching an oil filter for filtering the engine oil may be attached. A gasket is also interposed between such components and the engine body.

In the manufacture of such a structure such as an engine, it is necessary to confirm whether or not the seal member has been forgotten (out of stock) after assembly of the structure or whether there is an abnormality in the assembly of the seal member. become. There is no difficulty in checking for missing or improper assembly of the seal member if it is easy to visually recognize the assembled seal member from the outside. Inspections need to be performed without adverse effects on the body. Therefore, conventionally, for example, an inspection method as shown in FIG. 6 has been considered.

[0006] The inspection method shown in FIG. 6 is based on the presence / absence of a gasket 3 between an engine main body (work: inspection object) 1 and a component (here, an oil filter bracket or an oil pump case) 2 attached thereto. Is a method of detecting In this inspection method, as shown in FIG. 6, a leak tester 4 is attached to one opening of the oil line 1A of the engine body 1, and the oil in the oil line 1A such as the other opening of the oil line 1A is discharged to the outside. All the leaked parts should be equipped with the sealing jig 5 and the oil line 1
A is filled with oil. When the leak tester 4 detects oil leak from the oil line 1A, it is determined that the gasket 3 is missing or abnormal.

That is, when the pressure in the oil line 1A is increased by the leak tester 4, if there is no oil leak from the oil line 1A, the actual oil pressure in the oil line 1A increases according to the pressurizing operation by the leak tester 4. .
On the other hand, if there is a leak of oil from the oil line 1A, the actual oil pressure in the oil line 1A does not rise so much as to correspond to the pressurizing operation even if the pressurizing operation by the leak tester 4 is performed. Thus, the leak of the oil from the oil line 1A can be detected by the leak tester 4,
If there is such an oil leak, it can be estimated that the gasket 3 has been forgotten to be assembled or the gasket 3 has an abnormality.

[0006]

As described above, in order to detect an oil leak caused by a missing or abnormal seal member using a leak tester, as described above,
Oil lines must be fully pressurized. In other words, even if the seal member is missing or abnormal, the oil leak cannot be easily detected by slightly applying pressure to the oil line.

However, when the oil line is excessively pressurized, a seal member such as an oil seal provided around the oil line is excessively deformed, and the work (that is, the oil seal) is deformed.
It is not possible to pressurize the oil line to a degree sufficient to detect oil leaks, as this may damage engine and other structures. Therefore, it is actually difficult to check for missing seal members using a leak tester.

[0008] In the inspection using a leak tester, the work of installing the sealing jig 5 and the oil line 1A are performed on all parts of the oil line 1A where the oil leaks to the outside.
A must be filled with oil, and after inspection, it is also necessary to discharge the oil in the oil line 1A and to remove the attached sealing jig 5.
There is also a problem that the inspection work requires time and labor.

It is also conceivable to perform a leak test using air instead of oil. However, in general, the accuracy of the surface roughness and undulation of the sealing surface of the component parts is maintained at a high level in the machined state. The leak test by
Air pressure for detection is absorbed by volume changes in other areas of the engine, making it impossible to determine leaks.
It is more difficult to check for missing seal members.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is possible to reliably determine the quality of a seal member or the presence or absence of a shortage without affecting a structure having a seal member in a simple operation process. It is an object of the present invention to provide an inspection device which can perform the inspection.

[0011]

Therefore, the inspection apparatus of the present invention vibrates one of the two members by vibrating means, and vibrates according to the vibration of one of the members by vibrating. Vibration of the other member of the two members is detected by the vibration detecting means. Further, the vibration electric signal of the other member detected by the vibration detecting means is fast Fourier-transformed by the converting means, and the frequency characteristic of the vibration of the other member obtained by this is output.

By comparing the frequency characteristic of the vibration of the other member output from the conversion means with the reference characteristic, the quality of the sealing member interposed between the two members (including whether the sealing member is missing or not) is determined. Can be determined.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 to 5 show an inspection apparatus as an embodiment of the present invention, and FIG. It is a block diagram. As shown in FIG. 1, an attached part (here, an oil filter bracket or an oil pump case) 2 is attached to an engine body 1 as a work (object to be inspected) via a gasket 3 as a seal member. . That is, the two members of the engine body 1 and the attached component 2 are fastened with the gasket (seal member) 3 interposed therebetween.

A vibrator 11 as a vibrating means is mounted on an attached part (oil filter bracket or oil pump case) 2 which is one of the members, and a vibration detecting means is mounted on the engine body 1 which is the other member. The vibration sensor 12 is mounted. In the present embodiment, the vibration sensor 13 is further mounted on the attached component 2 side, so that the vibration of the attached component 2 can be measured. The outputs of these vibration sensors 12 and 13 are output to an FFT analyzer (fast Fourier transform analyzer) 14 as a converting means.

The vibrator 11 is to excite the attached component 2 with an impulse, and may be a simple hammer. In order to keep the input level constant, for example, electric power from a power supply (not shown) is passed through a controller (not shown). What is necessary is just to use the electric type shaker operated by a command. As the vibration sensors 12 and 13, an acceleration sensor that converts a displacement acceleration generated in the engine body 1 or the attached component 2 into an electric signal and outputs the electric signal is suitable.

The FFT analyzer 14 includes the vibration sensor 1
2 and 13, that is, a displacement acceleration signal (a voltage signal, a current signal, or the like) generated in the engine body 1 or the attached part 2, and Fourier-transformed.
The frequency characteristics of the vibration of the engine body 1 and the attached parts 2 obtained as described above can be displayed on a display, for example. further,
The FFT analyzer 14 Fourier-transforms these displacement accelerations based on the respective displacement acceleration signals generated in the engine body 1 and the attached part 2, and then converts the converted value of the acceleration of the engine body 1 into the converted value of the acceleration of the attached part 2. To obtain the transfer function.

Here, the quality of the gasket 3 is determined (in this case, it is determined whether the gasket 3 has been forgotten to be assembled).
Will be described. When the attached component 2 is subjected to impulse vibration by the vibrator 11, the temporal change of the vibration amplitude of the engine body 1 is as shown in, for example, FIGS. 2 (A) and 3 (A). That is, when the attached component 2 vibrates in response to the impulse excitation, the vibration is transmitted to the engine main body 1 via the gasket 3 and other fastening members. The detected information is sent from the vibration sensor 12 to the FFT analyzer 14. The vibration generated in the attached component 2 on the vibration side is detected by the vibration sensor 13, and this detection information is also transmitted to the vibration sensor 1.
3 to the FFT analyzer 14.

In the FFT analyzer 14, the input vibration amplitude data is subjected to a fast Fourier transform, for example, as shown in FIG.
(B), as shown in FIG. 3 (B), vibration characteristics (power spectrum) of the engine body 1 and the engine body 1
Display or output the vibration characteristics (transfer function) between the device and the attached component 2. 2 (B) and 3 (B), predetermined frequency regions (regions denoted by reference numerals A1 and A2 surrounded by alternate long and short dash lines)
Focusing on, there is a large difference in characteristics between a normal state, that is, when there is the gasket 3 (FIG. 2B), and an abnormal state, that is, when there is no gasket 3 (FIG. 2B). Understand.

The main parts A1 and A2 in FIGS. 2B and 3B
FIG. 4 is an enlarged schematic view of FIG. In FIG. 4, a solid line B1 indicates a case where a gasket is present [FIG.
(B) shows a schematic enlarged view of a main part], and a broken line B2 shows a case without a gasket (a schematic enlarged view of a main part of FIG. 3 (B)). A predetermined inspection window W is provided in the main parts A1 and A2.
1, and the power spectrums B1,
The presence or absence of the gasket is determined by comparing B2 or the peak frequency of the transfer function with its gain.

That is, in the normal state (when there is the gasket 3) and in the abnormal state (when there is no gasket 3), as shown in the figure, the peak frequency in the inspection window W1 is related to the power spectra B1 and B2 or the transfer function. And gain are different from each other. Therefore, the first determination method according to the present embodiment is a power spectrum B1 in a normal state (in the case of a non-defective product having the gasket 3).
Alternatively, based on the peak frequency and the gain in the transfer function inspection window W1, a region having a wider range for both the peak frequency and the gain (this is defined as a non-defective determination range) is set, and the inspection target data ( If the power spectrum or the transfer function's peak frequency and gain in the inspection window W1 are out of the acceptable product determination range, it is determined that there is an abnormality (defective product without the gasket 3).

Of course, if the accuracy of the power spectrum or the transfer function is high, the non-defective product judgment range can be set narrower, and the present invention is not limited to whether the gasket 3 is missing or not. In some cases, the peak frequency and the gain of the power spectrum or the transfer function in the inspection window W1 are out of the non-defective judgment range, and thus can be detected.

When a power spectrum or a transfer function as shown in FIG. 4 is processed by a band-pass filter, for example, data as shown in FIG. 5 is obtained. In FIG. 5, the curves show the power spectrum or the transfer function, the bar graphs C1 and C2 show the power spectrum or the transfer function processed by the band-pass filter, and the bar graph C1 shown by the solid line and the like show the solid line in FIG. The normal time corresponding to B1 is shown, and the bar graph C2 indicated by a broken line is an abnormal time corresponding to the broken line B2 in FIG.

When comparing the bar graph C1 in the normal state and the bar graph C2 in the abnormal state, in the example shown in FIG. 5, both peak bands themselves are different, but there is also a clear difference in the gain of both peak bands. The quality can also be determined by comparing such a peak band with its gain. In other words, if the power spectrum or the transfer function is processed by the band-pass filter after appropriately setting the bandwidth of the band-pass filter, it becomes apparent that the normal peak band and its gain and the abnormal peak band and its gain are between. You can make a difference.

Therefore, in the second judgment method according to the present embodiment, as shown in FIG. 5, a predetermined good judgment range is set for a peak band in a normal state (when the gasket 3 is present) and its gain. If the peak band and its gain are out of the non-defective determination range, it is determined that there is an abnormality (when there is no gasket 3). Of course, in the case of such a determination method as well, depending on the setting of the band width of the band-pass filter and the accuracy of the power spectrum or the transfer function, it is not limited to whether the gasket 3 is out of stock or not. However, this can also be detected when there is a defect, for example.

An inspection apparatus as one embodiment of the present invention
Since the inspection is performed as described above,
According to the present inspection apparatus, the engine body and its attached parts (oil filter bracket or oil pump case) can be inspected in a simple inspection process without damaging the inspection object.
Whether the seal member (gasket) interposed between the two members is good or not (including whether or not it is missing) can be reliably determined.

Of course, the present invention is not limited to the above-described embodiment, and the above-described embodiment can be applied in various modifications. For example, in the above-described embodiment, in addition to the power spectrum based on the vibration information of the engine body 1 obtained from the vibration sensor 12, a vibration sensor 13 for detecting vibration generated in the attached part 2 on the vibration side is further added. The transfer function obtained from the vibration information 1 and the vibration information of the attached component 2 on the vibrating side is also used to determine the quality of the seal member (gasket).
The pass / fail judgment may be performed using only the power spectrum (in this case, the vibration sensor 13 is unnecessary), or the pass / fail judgment may be performed using only the transfer function.

In the above-described embodiment, the determination is made based on the peak frequency and the peak gain of the power spectrum or the transfer function within a predetermined inspection window. However, the determination may be made only by the peak frequency or only the peak gain. Further, in the present embodiment, although the determination itself is made artificially, whether or not the predetermined peak frequency, peak gain, and the like of the inspection data are within the acceptable product determination range can be easily determined using a computer or the like. Therefore, such determination can be automated.

Further, the present invention is not limited to the gasket interposed between the engine body and its attached parts as in the present embodiment.
Of course, it can be widely applied to the quality judgment of a seal member interposed between two members such as an O-ring other than a gasket.

[0029]

As described above in detail, according to the inspection apparatus of the first aspect of the present invention, the inspection object is not damaged and a simple inspection process is performed between the two members. The quality of the interposed seal member (including whether it is missing or not)
Can be reliably determined, and for example, the quality of a seal member such as a gasket mounted on the engine can be easily and reliably determined.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an inspection device as one embodiment of the present invention.

FIG. 2 shows inspection data on a normal inspection object by an inspection apparatus as one embodiment of the present invention;
(A) is a diagram showing a vibration state of the other member of the inspection object caused by vibration applied to one member, and (B) is a diagram showing a power spectrum obtained from a vibration state of the other member of the inspection object. It is.

FIG. 3 shows inspection data on an inspection object having a missing item by an inspection device as one embodiment of the present invention;
(A) is a diagram showing a vibration state of the other member of the inspection object caused by vibration applied to one member, and (B) is a diagram showing a power spectrum obtained from a vibration state of the other member of the inspection object. It is.

FIG. 4 is a diagram illustrating a schematic power spectrum for describing a first determination method by the inspection apparatus as one embodiment of the present invention, represented by an amplitude gain.

FIG. 5 is a diagram illustrating a result of bandpass analysis of a schematic power spectrum for explaining a second determination method by the inspection apparatus as one embodiment of the present invention.

FIG. 6 is a schematic configuration diagram showing a conventional inspection device.

[Description of Signs] 1 member [engine body as work (object to be inspected)] 2 member [attached parts (oil filter bracket or oil pump case)] 3 gasket as seal member 11 vibrator 12 as vibrating means 12 , 13 Vibration sensor as vibration detecting means 14 FFT analyzer (fast Fourier transform analyzer) as converting means

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenichi Takahashi 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (72) Inventor Shinji Takeuchi 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi F-term (reference) 2G047 BC04 EA11 GG12 GG33

Claims (1)

[Claims] 1. Two members fastened with a seal member interposed therebetween, a vibrating means for vibrating one of the two members, and a vibration of the one member by the vibrating means. Vibration detecting means for detecting vibration generated in the other member of the two members, and vibration of the other member obtained by Fourier transforming a vibration signal of the other member detected by the vibration detecting means. And a converting means for outputting the frequency characteristic of the sealing member. By comparing the frequency characteristic of the vibration of the other member output from the converting means with a reference characteristic, the quality of the sealing member can be determined. An inspection device, characterized in that: