JPS638525A - Automatic gastightness inspecting instrument for article - Google Patents

Abstract

PURPOSE:To automatically judge whether the article under inspection is a nondefective or not by detecting the absence or presence of bubbles produced in a water tank by pressurizing and supplying a gas to a clamped article to be inspected. CONSTITUTION:An oxygen sensor 8 to be inspected is clamped by using a clamping device 7 so as to gastightly wrap the circumference of the sensor 8. Then, an inspecting gas is pressurized and supplied from the side of one end of the clamped sensor 8 via a pipe 33 and a gas enclosing cover 32. When the oxygen sensor 8 is a defective with respect to gastightness, the inspecting gas is led to a water tank 11 via a passage 26 formed in the clamping device 7. A bubble detecting instrument 10 detects bubbles produced by the introduction of the inspecting gas and outputs a detected result to a controller 12. The controller 12 judges the presence or absence of the bubbles based on the detection signals of the instrument 10, thereby inspecting whether the gastight condition of the oxygen sensor 8 is proper.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an automatic airtightness inspection device for articles such as oxygen sensors.

<Prior art> Platinum electrodes are coated on the inner and outer surfaces of a ceramic tube having a closed end, and the electrodes on the outer surface are brought into contact with the exhaust gas of an internal combustion engine, and the electrodes on the inner surface are brought into contact with the atmosphere. There is a conventional airtightness inspection device for an oxygen sensor that detects the oxygen concentration in exhaust gas using the electromotive force generated during the test, as shown in FIG.

In this device, an oxygen sensor 2 is disposed in a water tank 1, one end of which is supported on a support stand 3, and the oxygen sensor 2 is clamped by a clamp device 4. Then, air at a predetermined pressure is supplied into the oxygen sensor 2 for a set period of time from an external pipe line 5 connected to the end of the support base 3 of the oxygen sensor 2, and air bubbles are generated from the end of the oxygen sensor 2 on the clamp side. The presence or absence of airtightness is determined visually and whether the airtightness is good or bad is inspected.

<Problems to be solved by the invention> However, in such a conventional airtightness inspection device, the presence or absence of bubble generation in multiple oxygen sensors 2 must be visually determined at the same time, and this determination is difficult. It's easy to miss.

Further, even if a defective work is overlooked, no alarm is issued, and the defective work cannot be reliably sorted.

Furthermore, when clamping or unclamping the oxygen sensor 2,
Bubbles other than the original defective element of the oxygen sensor 2 may occur, but it is difficult to determine whether the bubbles are related to the defective element of the oxygen sensor 2, and re-examination may be required. takes extra effort.

As a result of the above, the conventional device has a major problem of poor reliability as a device.

Therefore, in view of the above-mentioned conventional situation, the present invention aims to provide a highly reliable device by automating airtightness inspection.

Means for Solving the Problems> Therefore, the present invention provides a clamping device that clamps an object to be inspected so as to airtightly wrap around the object to be inspected, and a clamp device that clamps an object to be inspected so as to airtightly wrap around the object to be inspected, and a device for inspecting the clamped object to be inspected from one end side. a test gas supply device that supplies σ gas under pressure; a water tank into which the test gas is introduced as bubbles through a passage formed integrally with the clamp device so as to communicate with the other end side of the object to be inspected;
a bubble detection device that detects the bubbles in the water tank;
A control device that operates an airtightness determination device that notifies the presence or absence of bubble detection based on a detection signal emitted from the bubble detection device.

With this configuration, when gas is supplied under pressure to the clamped article to be inspected, no air bubbles are detected in good items;
In the case of defective products, air bubbles are detected, and the airtightness determination device determines this, thereby automatically performing an airtightness inspection.

(Example of Actual Can) Hereinafter, embodiments of the present invention will be described based on FIGS. 1 to 6.

FIG. 1 is a schematic diagram of an embodiment of an automatic airtight inspection according to the present invention, where 6 is an apparatus main body, and 7 is an airtight view of an oxygen sensor 8 as an article to be inspected disposed in the apparatus main body 6. A clamp device clamps the oxygen sensor 8 so as to wrap it around the oxygen sensor 8; 9 is a test gas supply device that pressurizes air as a test gas from one end side of the oxygen sensor 8 clamped by the clamp device 7; and 10 is a test gas supply device A sensor 12 is a bubble detection device that detects bubbles in a water tank 11 into which the test gas is introduced as bubbles through a passage formed integrally with the clamp device 7 so as to communicate with the other end side of the oxygen sensor 8. An OK lamp 13 (good product determination) consisting of a light emitting diode as an airtightness determination device that indicates the presence or absence of air bubble detection based on the detection signal emitted from the sensor 10;
A control unit (second
(see figure).

Here, the structure of the device main body 6 will be explained based on FIG. 3.

That is, in the main body 6 of the apparatus, clamping devices 7 for oxygen sensors 8 are provided in two rows of four oxygen sensors 8 each, corresponding to the eight oxygen sensors 8 to be tested.

As shown in FIG. 4, this clamp device 7 includes a workpiece holder 16, a workpiece holding spring 17, a stopper 18, a workpiece storage airtight tube 19, an airtight shaft metal 20, a fixing nut 21, a washer 22, a nut 23, and an airtight shaft. It is composed of a pressure spring 24 and the like.

Is that a clamp device? ! ! When assembling 7,
Work holding spring 1 is placed inside the work storage airtight cylinder 19.
7, then insert the work holder 16 and attach the stopper 18. A nut 23 is attached to the shaft portion 19a integrally formed at the upper end of the work storage airtight cylinder 19,
An airtight axial pressure spring 24 is interposed between the nut 23 and the airtight shaft metal 20. Then, the workpiece storage airtight cylinder 19 is attached to the airtight shaft metal 20 which is assembled to the mounting plate 25.
Penetrate the shaft portion 19a of the
2, the work storage airtight cylinder 19 is supported on the mounting plate 25.

A through hole 16a is formed in the work holder 16 of the clamp device 7, and a passage 2 passes through from the work storage space 19b at the lower end of the work storage airtight cylinder 19 to the upper end of the shaft portion 19a.
6 is formed.

As described above, the eight clamp devices 7 are supported by the mounting plate 25 horizontally disposed within the device main body 6, and the mounting plate 25
is moved up and down within the device main body 6 by the cylinder device 27. The main body 27a of the cylinder device 27 is fixed to the outer surface of the upper wall of the device main body 6, and the tip of the operating shaft 27b is connected to the center of the mounting plate 25 via a joint 28. One end of a guide shaft 29 extending vertically is connected to both ends of the mounting plate 25, and the other end of the guide shaft 29 penetrates to the outside via a guide tube 30 fixed to the inner surface of the earthen wall of the device main body 6. are doing.

A gas introduction pipe 31 is connected to the upper end opening of the passage 26 of the clamp device 7, that is, the upper end opening 19c of the shaft portion 19a of the work storage airtight cylinder 19, and the gas introduction pipe 30 is disposed inside the apparatus main body 6. Aquarium 1 fixed to mounting plate 25
1, and the tip is open.

A sensor 10 serving as a bubble detection device is disposed near the opening at the tip of the gas introduction pipe 31 in the water tank 11 .

As shown in FIG. 4, the oxygen sensor 8 to be tested is inserted into the set hole 6a formed at the bottom of the main body 6 of the device.
It is set to penetrate vertically with a facing upward. A gas introduction cover 32 is attached to the lower surface of the bottom of the device body 6 so as to cover the lower end of the oxygen sensor 8, and air from an air pump (not shown) is supplied under pressure via a pipe 33. There is.

In this configuration, the clamp device 7 is lowered with the oxygen sensor 8 set in the set hole 6a of the device main body 6 as shown in FIG. Make it abut around the hole 6a.

At this stage, the oxygen sensor 8 is clamped in a state where it is hermetically enclosed within the workpiece storage space 19b of the workpiece storage airtight cylinder 19.

Here, air from an air pump (not shown) is supplied to the pipe 33.
If the oxygen sensor 8 is defective in terms of airtightness, the air passes through the oxygen sensor 8 and reaches the passage 26, and the air enters the shaft portion 19a of the work storage airtight cylinder 19. The gas is introduced into the water tank 11 from the upper end opening 19C via the gas introduction pipe 31, and is emitted into the water tank 11 from the tip of the pipe 31. Air becomes bubbles in the water tank 11, and the sensor 10 detects the bubbles.

Next, the functions of the control unit I2 will be explained according to the time chart of FIG. 5 and the flow chart of FIG. 6.

As shown in Fig. 5, when the door switch is turned on, bubble detection is performed for a predetermined measurement mask time (O~15
sec) and enters detection. Predetermined detection time (0 to 1
Data hold is performed after 5 seconds).

This data hold continues until the door switch is turned off and then turned on. During data hold, the OK clamp 3 (good product judgment) or NG clamp 4 and NG buzzer 15 (defective product judgment) are lit and activated according to the judgment result, and the door switch for the NG buzzer 15 is turned off. It will be deactivated at that point.

Next, to explain the flowchart, in FIG. 6, first, when a reset command is issued after power-on, S
In step 1, initial settings are made, and in step S2, the OK clamp 3, NG clamp 4, and NG buzzer 15 are turned off. Next, in S3, it is determined whether or not the door switch has been turned off, and if it is off (YES), the process proceeds to S4, where it is determined whether or not the door switch has been turned on. This determination is repeated until the door switch is turned on. If it is turned on (YES), the process proceeds to S5 where the OK clamp 3, NG clamp 4, and NG buzzer 15 are turned off. In S6, a predetermined measurement mask time is elapsed. , if this mask ends in S7 (YES)
, 38, and if No, the process proceeds to S4.

In S8, reading is performed by the sensor 10, and in S9, a determination is made as to whether this reading has been completed until this is determined. If it is determined that the reading has finished (YES),
At 310, the reading result by the sensor 10 is determined. If this judgment result shows that the product is good without bubbles, S
Proceed to step ll, turn on the OK lamp I4, and proceed to step S12. In S12, it is determined whether the door switch is turned off. This judgment is repeated until the door switch is turned off.
If it is turned off (YES), the process proceeds to S4. If the SIO determines that the read result by the sensor 10 is a defective product with air bubbles, the process proceeds to S13 and 514, where the NO lamp 14 and NG buzzer 15 are turned on, and the process proceeds to S15.

In S15, it is determined whether or not the door switch is in the on state. If the door switch is in the off state (No), the process proceeds to S17, where the NG lamp 14 is turned off, and if the door switch is in the on state (YES). , proceed to 816. In S16, N
Determine whether the stop switch of the G buzzer 15 is turned on or not, and if it is turned on (YES), proceed to 517,
Turn off the NG buzzer 15 and proceed to S4. If it is not turned on (NO), the process proceeds to S13.

As explained above, in the airtightness inspection device with this configuration,
The presence or absence of bubble generation in multiple oxygen sensors 8 is automatically determined, eliminating the need for visual inspection, so defects can be detected without being overlooked, and as a result of eliminating visual inspection work, the work is less labor-intensive and improves work efficiency. This allows reliable selection of defective workpieces.

Furthermore, when clamping or unclamping the oxygen sensor 8,
Bubbles other than the defective element of the original oxygen sensor 8 may occur, but since the measurement mask time and detection time of the inspection can be set arbitrarily, only the bubbles of the defective element can be detected.
Detection ability can be improved.

<Effects of the Invention> As explained above, according to the present invention, by supplying gas under pressure to a clamped article to be inspected, a detection device automatically detects the presence or absence of air bubbles generated in a water tank. Since the structure is configured to automatically determine good and defective products, there is no need to visually detect the presence or absence of air bubbles.
Defects can be detected without being overlooked, and as a result of eliminating visual inspection work, work is less labor-intensive, workability is improved, defective workpieces can be reliably sorted, and automation improves the ability to detect only bubbles, which are defective elements. It is also possible to improve the detection ability.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing an embodiment of the airtightness inspection device for articles according to the present invention, Fig. 2 is a schematic diagram showing a control unit in the same embodiment, and Fig. 3 is a schematic diagram showing the main body structure of the device in the same embodiment. The figures are a time chart and a flow chart explaining the functions of the control unit in the embodiment, and FIG. 7 is a schematic diagram of a conventional device. 6...Device body 7...Clamp device 8...
・Oxygen sensor 9...Inspection gas supply device 10
... Sensor 11 ... Water [12 ... Control unit 13 ... OK lamp 14 ... NG clamp 15 ... NG buzzer 26 ... Passage
32...Gas introduction cover 33...Pipe characteristics Applicant: Japan Electronics Co., Ltd. Agent
Patent Attorney Fujio Sasashima Figure 3 (A) lW3 CB) Figure 4

Claims (1)

[Claims] a clamping device that clamps the object to be inspected so as to airtightly wrap around the object to be inspected; an inspection gas supply device that supplies an inspection gas under pressure from one end side of the clamped object to be inspected; a water tank into which the test gas is introduced as bubbles through a passage formed integrally with the clamp device so as to communicate with the other end of the test article; a bubble detection device for detecting the bubbles in the water tank; and a bubble detection device. 1. An automatic airtightness inspection device for articles, comprising: a control device that operates an airtightness determination device that notifies the presence or absence of bubble detection based on a detection signal emitted from the device.