JP3223463B2 - Airtight inspection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for inspecting the airtightness of a work having a space which requires airtightness inside the work.

[0002]

2. Description of the Related Art For example, Japanese Patent Application Laid-Open No. Hei 4-231835 discloses a conventional apparatus in which compressed air is supplied to an internal space of an airtight work such as a fuel tank and the like, and a pressurized state is formed. When immersed in, if airtightness is not maintained, part of the pressurized air leaks into the water and focuses on rising in the water tank as bubbles, collecting the bubbles in a foaming hood, It is known that air bubbles are guided to a test tube attached to the top of the foam collecting hood, and an airtightness test is performed by detecting the presence or absence of the bubbles by a bubble sensor attached to the test tube. I have.

[0003]

Immediately after the work is immersed, air bubbles adhere to the surface of the work or the surface of a jig for holding the work in water. Therefore, after immersion, it is necessary to remove air bubbles adhering to the surface by spraying a water stream onto a work or a jig. However, the bubbles thus forcibly removed rise into the foaming hood and come into contact with the inner wall of the foaming hood. In this case, since the size of the bubbles is relatively small and the buoyancy is small,
The rising force of the bubbles is hindered by the adsorbing force between the inner wall of the foam collecting hood and the rising speed of the bubbles is significantly reduced. However,
The airtightness test cannot be started until the air bubbles that have entered the bubble collecting hood have completely risen through the test tube, and thus the cycle time required for the test is prolonged.

[0004]

[0005] The present invention has been made in view of the above problems, after removing the air bubbles adhering to the workpiece or the jig surface in a short time to provide a hermetic inspection apparatus Kiru de to the state may perform leak test The purpose is to:

[0006]

In order to achieve the above object, according to the first aspect of the present invention, a foam collecting hood provided with a test tube at the top is provided in a water tank, and is immersed below the foam collecting hood. In a device for guiding air bubbles rising from a work that has risen into a test tube, detecting the air bubbles, and performing an airtightness inspection, the bubble collection hood is provided so as to be freely offset from an upper position of the work in a state of being submerged, and the bubble collection hood is provided. At the offset of
Characterized in that the first bubble removal means for injecting a water flow and arranged to work.

[0007] The second aspect of the present invention is the same as the first aspect of the invention.
In addition, at the time of offsetting the foam collecting hood, the foam collecting hood is
A second air bubble removing means for injecting a water flow into the air outlet .

According to a third aspect of the present invention, in the first or second aspect of the present invention, the upper end opening of the test tube is provided below the water surface.

[0009]

When a water flow is jetted from the first bubble removing means to the work or the jig in a state where the foam collecting hood is offset from above the work, the bubbles adhering to the surface of the work or the jig are separated and rise. At this time, since the bubble collecting hood is not located above the workpiece, the bubbles rise to the water surface without being decelerated. On the other hand, when air bubbles adhere to the inner wall of the foam collecting hood, the air bubbles are peeled off from the inner wall by injecting a water flow from the second air bubble removing means, and the air bubbles are forcibly removed from the inside of the foam collecting hood.

[0010]

When oil or dirt is attached to the work, the work separates and floats on the water surface. At this time, if the tip of the test tube protrudes above the water surface, the surface of the test tube may be at an intermediate position. And the inner and outer surfaces of that portion are soiled. In such a case, if the upper end opening of the test tube is positioned below the water surface, oil and dirt entering the test tube will flow out from the upper end opening of the test tube, and the test tube will not be contaminated. .

[0012]

1 and 2, reference numeral 1 denotes a water tank,
The water tank 1 is provided with a work lifting / lowering device 2 for raising and lowering the work W and immersing the work W in the water tank 1, and an offset for conveying the work W to a position above the work W and a position offset from the upper position in a state where the foam collection part 33 is submerged. The device 3 is attached. By the way, the work W is a damper for a vehicle that requires airtightness in the present embodiment.

The work lifting device 2 is provided with a lifting table 25 to which a jig 21 for holding the work W is attached. The work W is clamped by an actuator 23a mounted on the lifting table 25 to be a clamp claw. The jig 2 is pressed against the air injection portion 22 by the
It is held at 1. A compressor (not shown) is connected to the air injecting section 22, and is configured to fill the work W with compressed air. The elevating table 25 is moved up and down along the columns 24 erected on the outer wall of the water tank 1 by the operation of the elevating cylinder 26.

On the other hand, the offset device 3 is provided with an offset cylinder 31 horizontally.
The foam collecting section 33 is attached to 1 via a bracket 32. As shown in FIG. 3,
A sealed space covered with a surrounding tube 33c is formed above a reverse funnel-shaped foam collecting hood 33a having a test tube 33b inclined at the top, and a bubble sensor 33 is provided in the sealed space.
d is attached across the inspection tube 33b. The bubble sensor 33d is an optical sensor having a light projecting unit and a light receiving unit. When bubbles rise in the test tube 33b, part of the light projected from the light projecting unit to the light receiving unit is blocked by the bubbles. Is a sensor that detects that the vehicle has passed. In addition, the inspection tube 33b
The upper end opening 33e is located below the water surface H and is open to the water. Bubbles rising in the inspection tube 33b and oil attached to the work W are discharged into the water from the upper end opening 33e. You.

On the inner bottom surface of the water tank 1, a first nozzle 41 serving as first air bubble removing means is provided below a position where the work W is immersed, and a second air bubble removing means is provided below an offset position of the foam collecting section 3. A second nozzle 42 as a means is provided, and water supplied from a pump 43 is both sprayed toward the workpiece W and the jig 21 in the immersion state, and the second nozzle 42 is in an offset state. Is configured to be sprayed toward the inside of the foam collecting hood 33a of the foam collecting section 33 in the above.
Further, when the foam collecting section 33 is in the offset state, the bubble sensor 33 is provided in the foam collecting hood 33a via the air valve 5.
A nozzle 51 for sending out bubbles for the operation test of d is provided.

Next, the operation of the inspection apparatus having the above configuration will be described with reference to FIG. First, before the work W is immersed, the foam collecting section 33 is offset, and at the start of operation or every several cycles, the pump 43 is operated to spray water from the second nozzle 42 into the foam collecting hood 33a, thereby causing the foam collecting hood 33a. 33a
Remove the air bubbles adhering to the inner wall of the. When the airtight inspection is started, first, the actuator 23a is operated, and the work W is held on the jig 21 by the clamp claws 23. Next, the elevating table 25 is lowered by operating the elevating cylinder 26 to immerse the work W, and a compressor (not shown) is operated to pressurize the inside of the work W. When the immersion of the work W is completed, the pump 43 is operated to remove bubbles adhering to the surface of the work W and the jig 21 by the water jet injected from the first nozzle 41. The removed bubbles rise to the water surface at a relatively high speed because there are no obstacles above. Subsequently, the operation of the pump 43 is stopped, and the foam collecting section 33 is moved to the set position above the workpiece W by the operation of the offset cylinder 31. After waiting for a predetermined time until the water flow due to the movement of the foam collecting section 33 is settled, the air bubble is removed. Sensor 3
The detection of bubbles by 3d is started. At this time, if there is an air leak from the work W, air bubbles due to the air leak are detected by the air bubble sensor 33d, and it is determined that the airtightness is poor. Then, when the detection is performed for a predetermined time, the foam collecting section 33 is retracted to the offset position, then the compressor is stopped, and the elevating table 25 is raised to take out the work W from the water, and the clamp claw 23 is brought into the unclamped state. The first nozzle 41
While removing bubbles on the surface of the workpiece W and the shaft 21 by the water flow from the nozzle and after the detection of the bubbles is completed and the bubble collecting section 33 is retracted to the offset position, the air valve 5 is opened to generate bubbles from the nozzle 51. Then, the operation of the bubble sensor 33d is checked.

[0017]

As is apparent from the above description, according to the first aspect of the present invention, after removing the air bubbles adhering to the surface of the work or the jig, a relatively high speed can be obtained without restraining the rise of these air bubbles. To shorten the time required for the airtight inspection.

According to the second aspect of the present invention, a bubble collecting hood is provided.
To collect bubbles adhering to the inner wall of the hood
Efficient removal at the position, further increasing the time required for airtight inspection
Can be shortened .

If the upper end opening of the test tube is located below the water surface as in the third aspect of the present invention, the middle of the test tube will not be stained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view taken along the line II of the configuration of an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II-II.

FIG. 3 is a partially enlarged view showing details of a foam collection section.

FIG. 4 is a timing chart showing operation contents.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Water tank 2 Work raising / lowering apparatus 3 Offset apparatus 21 Jig 33 Foam collecting part 33a Foam collecting hood 33b Inspection tube 33d Bubble sensor 33e Upper end opening part 41 1st nozzle (1st air bubble removal means) 42 2nd nozzle (2nd air bubble removal) Means) W work

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01M 3/06 G01M 3/10

Claims (3)

(57) [Claims] 1. A foam collecting hood having an inspection tube at the top is provided in a water tank, and air bubbles rising from a work immersed under the foam collecting hood are guided into the inspection tube, and the air bubbles are detected and airtight. In the inspection device, submerge the foam hood
Remains together with the workpiece upper position offset freely provided the state with the time of offset of said population foam hood, airtight inspection apparatus characterized by a first bubble removal means for injecting water into the workpiece and arranged. 2. The method according to claim 1, wherein said foaming hood is offset when said hood is offset.
The airtightness inspection apparatus according to claim 1, further comprising a second bubble removing unit that injects a water stream into the foam hood . 3. The airtightness inspection apparatus according to claim 1, wherein an upper end opening of the inspection tube is provided below the water surface.