JPH095202A - Vacuum leakage testing apparatus - Google Patents

Abstract

PURPOSE: To easily conduct an accurate inspection. CONSTITUTION: A reference position marking unit 40 is so provided as to collate with a leakage position distribution diagram formed by processing a signal by a vacuum leakage testing apparatus in which a plurality of small-sized acoustic sensors 6 for quantifying leakage are arranged in a lattice state in a vacuum box 10 and a conical sound collecting plate 70 is disposed at the front surfaces of the sensors 6, and outputs a sheet showing a fault position in an actual size. The sheet is provided for a material 20 to be inspected with the marking as a reference and a fault hole 21 is recognized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leak test, which is one of the test methods for test products of flat structures (including curved surfaces) of vehicles and the like. Regarding test equipment.

[0002]

2. Description of the Related Art A foam leakage test method for observing the formation of bubbles of a foaming liquid applied to an inspection surface, by applying pressure or vacuum to one of the inspection surfaces and observing gas leakage caused by a pressure difference between the inspection surface and the opposite side. However, if it is difficult to pressurize both the test surface and the back surface in an open state like a wall surface, the method of pressing the vacuum box against the test surface and exhausting the inside locally is adopted. Has been. Although a method of detecting a leaking sound with an acoustic sensor has been conventionally performed, none of them detects a sound leaking to the outside when the inside of a container or a pipe is pressurized, and is not structured to be combined with the vacuum method. ()

[0003]

Although it is possible to find the leaked portion from the inspection surface by the foam leakage test, it is difficult to automate the work because the inspector visually detects the foaming, and the leakage position is recorded. However, it was difficult to quantify the leakage amount. Especially for a large leak, there is a problem that once foaming, the foaming liquid is removed and the foaming stops, so that it can be observed only momentarily.

An object of the present invention is to enable easy and accurate inspection.

[0005]

The above-mentioned object is to show a plurality of acoustic sensors provided in a vacuum box and the sound collected by the acoustic sensors to determine the position of a defect in the vacuum box on a sheet. And an output device for outputting, and the output device is configured to show the defect position on the sheet in a one-to-one relationship with the size in the vacuum box. Can be achieved.

[0006]

When the vacuum box is applied to the object to be inspected and the vacuum generator is operated, the space surrounded by the vacuum box and the object to be inspected is in a vacuum state. In this state, if the inspection object has a penetration defect, the internal gas of the inspection object is sucked out according to the degree of vacuum in the space. When a gas such as air passes through the penetrating defect, a very weak rubbing sound is generated depending on the passing speed and the shape and size of the defect. This is captured by the acoustic sensor of the vacuum box, and the position of the penetration defect is shown on the sheet. In this case, the defect position is shown on the sheet in a one-to-one relationship with the size in the vacuum box. If there is a defect, the sheet is covered with the inspection object, and the actual position of the defect is recognized from the defect position displayed on the sheet.
Then, work such as repairing the found defect position is performed. Thus, the size of the inspected object is 1
Since the actual defect position is recognized using the sheet shown in the size of pair 1, the actual defect position can be easily recognized.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. The vacuum box 10 is placed on the object 20 to be inspected, and the inside of the vacuum generator 12 is used as a negative pressure for use. Vacuum box 10
A packing 11 is arranged in the opening of the. Vacuum box 10
Sound collecting plate 7 having a plurality of conical sound collecting holes 71 inside
0, and the acoustic sensor 6 is arranged in each sound collection hole 71. The acoustic sensor 6 is arranged in the expanding direction of the sound collecting hole 71, that is, in the opening direction of the vacuum box 10. The sound collector 70 is located relatively close to the opening of the vacuum box 20. The vacuum generator 12 is connected above the sound collecting plate 70. The volume above the sound collecting plate 70 is relatively large. The plurality of acoustic sensors 6 are arranged in a grid. The vacuum box 10 is provided with a reference marking device 40 for displaying the current position of the vacuum box 10, that is, the origin positions of the plurality of acoustic sensors 6 on the object to be inspected. The marking device 40 marks an L-shaped mark. The L-shaped mark indicates that the vacuum box 10 is located in the direction perpendicular to the two L-shaped pieces. The marking device 40 also prints the inspection number on the inspection object 20. The plurality of acoustic sensors 6 are connected to the signal processing display device 30 via signal lines 32, respectively. The signal processing display device 30 includes an output device 31.

When the vacuum box 10 is placed on the object 20 including the defect hole 2 and the inside of the vacuum box 10 is evacuated to a negative pressure by the vacuum generator 12, the vacuum hole 10 enters the vacuum box 10 through the defect hole 21. Atmosphere begins to leak. Leak sound 2 generated at this time
2 is detected by the acoustic sensor 6 and converted into an electric signal.
The electric signal is guided to the outside of the vacuum box 10 by the signal line 32 and input to the signal processing display device 30. Signal processing display device 31
Amplifies the signal for each acoustic sensor, performs necessary processing, displays it on the screen 50 of the signal processing display device 31, and outputs the content to the output device 31. Among the plurality of acoustic sensors 6, the sensor closest to the leak plate detects the strongest leak sound. The presence or absence of a defective hole is determined from the signal strength. Since the conical sound collecting hole 70 is provided for each acoustic sensor 6, it is possible to suppress a decrease in sensitivity between the sensors 6 to a small level, and at the same time, to cover a certain volume to be inspected. The number of sensors can be reduced.

Although the display contents of the signal display device 31 and the output device 31 can be various, the main one is the acoustic sensor 6.
And the position of the defective hole. Also, these indicate the size of the defective hole by color or size. Also, the inspection number is displayed. The output device 31 displays the marking device 40, the L-shaped mark, the position of the vacuum box 10, the positions of the plurality of acoustic sensors 6, and the position of the defect in the actual size. The marking device 40 and the vacuum box 10 indicate their positions by thin lines. The position of the acoustic sensor 6 is indicated by a circle, a dot, or +. The acoustic sensor 6 that has detected the defect is indicated by a large circle or a color. This may be indicated in proportion to the size of the defective hole. The output device 31 prints this on a sheet 51 such as transparent paper. The sheet 51 can be cut for each inspection number, that is, each time the vacuum box 10 is replaced.

When the inspection is completed and a defect is displayed, the sheet 51 is cut, applied to the object 20 to be inspected, and the actual defect position is recognized from the defect mark displayed on the sheet 51. Since the sheet 51 is transparent, the defective hole can be easily recognized. Since the inspection number and the L-shaped mark are provided on the inspected body 20, the sheet 51 can be easily applied. 3B shows a state in which the ends 51 and 51 are cut, and FIG. 3C shows an object to be inspected (welding line 2).
The state applied to 3) is shown. 52 is a defect mark. It should be noted that the mark 42 at the origin position in FIG. 3 has a triangular shape, and the mark 43 on the sheet 51 also has a triangular shape so that they are opposed to each other at the apexes.

According to this method, the inspector can carry out the test without continuously gazing at the object to be inspected as in the conventional foaming test.

The vacuum box 10 is kept airtight by a seal packing 11. However, if the flatness of the object to be inspected is not good, the airtightness of the seal portion may not be completely maintained, and a slight leak may occur. If the leak amount is small, this leak will not be an obstacle in a normal leak test, but in this embodiment in which leak noise is detected by a sensor, it may be difficult to distinguish between the leak of the DUT and the leak of the seal portion. Therefore, as shown in FIG. 4, two seal packings 111 and 112 are provided to form a double structure seal, and
Make sure that the space between the two seal packings is also evacuated. With such a structure, the leakage between the inner seal packing 112 and the object to be inspected is suppressed to a small level because the pressure difference between the two sides is small, and the leakage sound of the outer packing 111 is reduced by the inner packing. It is blocked by 112 and does not reach the sensor 6.

As the vacuum generators 12 and 121, a rotary vacuum pump or an air ejector is usually used. In either case, exhaust noise is generated and becomes noise in the leak test.
In order to reduce this noise, the length of the vacuum hoses 14 and 141 is set to 10 meters or more to prevent the exhaust noise from reaching.

The arrangement of the acoustic sensors may be staggered.

[0015]

According to the present invention, since a sheet in which the position of a defect is displayed in full scale is output, the actual position of the defect can be easily recognized.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a vacuum leak test apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view of a sound collector plate of the vacuum leak test apparatus of FIG.

FIG. 3 is a diagram showing steps for recognizing a defective hole by the vacuum leakage test apparatus of FIG.

FIG. 4 is a vertical cross-sectional view of a vacuum box of a main part of another embodiment of the present invention.

[Explanation of symbols]

6 ... Acoustic sensor, 10 ... Vacuum box, 11 ... Packing, 12
... vacuum generator, 13 ... vacuum gauge, 14 ... vacuum hose, 2
0 ... Inspected object, 21 ... Defect hole, 22 ... Leakage sound, 23 ... Welding line, 24 ... Packing leak, 30 ... Signal processing display device, 31 ... Output device, 40 ... Reference position marking device,
41 ... Marking signal, 42 ... Reference mark, 43 ... Alignment mark, 50 ... Display section, 51 ... Sheet, 52 ... Defect mark, 70 ... Sound collecting plate, 71 ... Sound collecting hole, 111 ... Outer packing, 112 ... Inner packing .

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tadashi Majima 3-2-1, Saiwai-cho, Hitachi-shi, Ibaraki Hitachi Engineering Co., Ltd. (72) Kenichi Kawai 3--2, Saiwai-cho, Hitachi, Ibaraki No. 1 in Hitachi Engineering Co., Ltd. (72) Inventor, Yoji Yoshida 32-1, Sachimachi, Hitachi City, Ibaraki Prefecture Hitachi Engineering Co., Ltd.

Claims (7)

[Claims] 1. A plurality of acoustic sensors provided in a vacuum box, and an output device for determining the sound collected by the acoustic sensors and outputting the position of the defect in the vacuum box by showing it on a sheet. The vacuum leak test apparatus is characterized in that the output device shows the defect position on the sheet in a full scale. 2. The vacuum leak test apparatus according to claim 1, wherein the sheet is transparent. 3. The vacuum leak test apparatus according to claim 1, wherein the output device shows the position of the acoustic sensor and the defect position on the sheet in a full scale. 4. The vacuum leak test apparatus according to claim 1, wherein the vacuum leak test apparatus includes a device that marks an origin position of the acoustic sensor on an object to be inspected, and the output device includes the origin position on the sheet. Is shown in the above-mentioned full-scale relationship. 5. A plurality of acoustic sensors provided in a vacuum box, an output device for determining a sound collected by the acoustic sensors and outputting a position of a defect in the vacuum box, and an origin position of the acoustic sensor. A vacuum leak tester consisting of a device for marking the object to be inspected. 6. A vacuum leak test apparatus comprising a plurality of conical sound collecting holes provided in the vacuum box toward the opening of the vacuum box, and acoustic sensors respectively arranged in the sound collecting holes. 7. A plurality of acoustic sensors provided in a vacuum box, a double packing installed along a contact portion of an object to be inspected of the vacuum box, a space between the double packings, and an inside of the vacuum box. A vacuum leak tester consisting of a connection port with a vacuum generator that is connected to each.