JPH1151800A - Sealing jig - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the wear of a sealing O-ring for a sealing jig which is used for a leak test. SOLUTION: An O-ring 4 which is fitted to the outer circumference of a jig body 5 is sandwiched between the step face (m) at the rear end of a protruding step part 6 at the tip pf the jig body 5 and the tip face (n) of a cylindrical pressure body 7 which is arranged and installed on the outer circumference of the jig body 5 so as to be movable to the axial direction. The outside diameter of the O-ring 4 in a normal state is set to be a little smaller than the inside diameter of a work hole 2. The jig body 5 is inserted into the work hole 2, only the cylindrical pressure body 3 is then advanced and moved, and the elastic O-ring 4 is compressed. Thereby, the outside diameter of the O-ring 4 is expanded so as to be elastic pressure contact with the work hole 2, and the work hole 2 is sealed. After a leak test, the cylindrical pressure body 7 is retreated, the O-ring 4 is returned to its original outside diameter, and the jig body 5 is pulled out from the work hole 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing jig used for a leak test of a hollow part of a work having a hollow part required to have a sealing property, and particularly to a sealing jig fitted to the sealing jig. The present invention relates to a sealing jig that prevents an O-ring from rubbing against a work.

[0002]

2. Description of the Related Art A round bar-shaped shaft member 20 as shown in FIGS. 4A and 4B is used as a sealing jig used for a leak test of a hollow work. A groove 21 is formed on the outer periphery of the distal end of the shaft member 20, and an elastic O-ring 22 is fitted into the groove 21. The outer diameter of the O-ring 22 is
4A, the outer diameter of the O-ring 22 in a normal state is set to be slightly larger than the inner diameter of the circular work hole 2 formed in the work 1 to be subjected to the leak test as shown in FIG. I have.

When the shaft member 20 is inserted into the work hole 2 as shown in FIG. 4B, the outer periphery of the O-ring 22 is pressed against the inner circumferential surface of the work hole 2 so that the O-ring 22 is slightly compressed.
In this state, the O-ring 22 slides on the inner peripheral surface of the work hole 2 in the axial direction. When the shaft member 20 is inserted to the fixed position of the work hole 2, the O-ring 22 elastically contacts the inner peripheral surface of the work hole 2 to seal the work hole 2, and a desired leak test is performed. When the leak test is completed, the O-ring 22 is slid along the inner peripheral surface of the work hole 2 and the shaft member 20 is extracted from the work hole 2.

[0004]

The sealing jig as described above has a simple structure. However, when the shaft member 20 is inserted into and removed from the work hole 2, the O-ring 22 is connected to the inner peripheral surface of the work hole 2 and the shaft member 20. Of the O-ring 2
2, the sealing property of the work hole 2 was deteriorated at an early stage.
Therefore, when the sealing property of the O-ring 22 deteriorates, the O-ring 22 is replaced with a new one. However, the frequency of replacement is uneconomical, and the trouble of parts management and replacement due to the O-ring replacement is reduced. There was a troublesome problem.

An object of the present invention is to provide a seal jig in which the O-ring has little wear.

[0006]

According to the present invention, a work hole formed in a work to be subjected to a leak test is inserted, and an elastic O-ring is brought into elastic contact with an inner peripheral surface of the work hole to seal the work hole. The above object is achieved by a seal jig having a structure in which an O-ring is supported by the following jig body, convex step portion, and cylindrical pressing body.

The jig main body is a round bar-shaped shaft on which an O-ring having an outer diameter smaller than the diameter of the work hole is fitted to the outer periphery of the tip. The convex step portion is provided on the outer periphery of the front end of the jig body with an outer diameter smaller than the diameter of the work hole, and has a step surface at the rear end with which an O-ring fitted to the jig body comes into contact. Shape. The cylindrical pressing body is a cylindrical body that is axially slidably fitted on the outer periphery of the jig body and has a distal end surface facing the O-ring, and has an outer diameter smaller than the diameter of the work hole.

In the seal jig of the present invention, after inserting the jig main body with the O-ring mounted thereon into the work hole with the protruding step first, the cylindrical pressing body is moved toward the protruding step side with respect to the jig main body. The O-ring is moved forward to press the O-ring against the step surface of the convex step, and the pressing force compresses the elastic O-ring so as to enlarge its outer diameter. And seal it. When the jig body inserted into the work hole is to be pulled out of the work hole, the jig body is pressed back from the O-ring, and the outer diameter of the O-ring is reduced to its original size. . When the sealing jig is inserted into and removed from the work hole in this manner, the O-ring does not strongly rub against the inner peripheral surface of the work hole during insertion and removal, and wear of the O-ring is reduced.

Further, in the present invention, when at least one of the tip end surface of the cylindrical pressing body and the step surface of the convex step is pressed against the O-ring by the cylindrical pressing body, the inner diameter of the O-ring is reduced. By making the O-ring a conical tapered pressing surface that presses the O-ring from the inner diameter side so as to expand the O-ring, the operation of expanding and contracting the O-ring can be further increased.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. 1 to 3. This embodiment is a sealing jig for sealing a work hole 2 at the time of a leak test of a work 1 shown in FIG. The jig body 5 is a round bar-shaped jig that is applied to
A projecting step 6 is integrally formed at the end of the jig main body, and an elastic O-ring 4 is fitted around the outer periphery of the end of the jig main body 5.
In this structure, a cylindrical pressing body 7 is fitted on the outer periphery rearward from the ring 4 so as to be slidable in the axial direction.

The jig main body 5 is a round bar having an outer diameter smaller than the inner diameter of the work hole 2, and a truncated cone-shaped cap-shaped protruding step 6 is coaxially formed at the end thereof. The outer diameter of the protruding step 6 is set to be larger than the outer diameter of the jig main body 5 and smaller than the inner diameter of the work hole 2, and a step surface m orthogonal to the outer periphery of the jig main body 5 is provided at the rear end of the protruding step 6. It is formed.

The outer diameter of the convex step 6 and the cylindrical pressing body 7 is
Desirably, it is set to be approximately the same as the outer diameter of the O-ring 4 or slightly smaller than the outer diameter of the O-ring 4.

An O-ring 4 is fitted between the outer periphery of the tip end of the jig main body 5 and the step surface m of the projecting step 6. The O-ring 4 is a rubber ring or the like having a circular cross-section, and its outer diameter in a normal state is set to be slightly smaller than the inner diameter of the work hole 2. The normal state of the O-ring 4 is shown in FIG. A cylindrical pressing body 7 is inserted into the jig main body 5 so as to sandwich the O-ring 4 between the step surface m of the convex step 6. Tip surface n of cylindrical pressing body 7
Opposes in parallel with the step surface m, and the O-ring 4 is pressed from both sides by the front end surface n and the step surface m. The axial movement of the cylindrical pressing body 7 is performed automatically or manually, for example, via a driving cylinder 8 connected to the rear end of the cylindrical pressing body 7.

The sealing jig 3 of the above embodiment is shown in FIG.
Used as (A) and (B). At the start stage of the leak test of the work 1, the sealing jig 3 is inserted into the work hole 2 while the O-ring 4 is lightly held between the convex step 6 and the cylindrical pressing body 7 as shown in FIG. I do. At this time,
The O-ring 4 is in a normal state in which the outer diameter is smaller than the inner diameter of the work hole 2. Therefore, the O-ring 4 is inserted into the work hole 2 without being rubbed against the inner peripheral surface of the work hole 2.

When the sealing jig 3 is inserted to the fixed position of the work hole 2, the cylindrical pressing body 7 is advanced with respect to the jig main body 5 using the driving cylinder 8 as shown in FIG. The O-ring 4 is moved and the O-ring 4 is pressed against the step surface m by the distal end surface n of the cylindrical pressing body 7. As a result, the elastic O-ring 4 is strongly pressed from both sides by the protruding step 6 and the cylindrical pressing body 7 and is deformed into a substantially elliptical cross section, thereby expanding the outer diameter of the O-ring 4. Of the workpiece hole 2 comes into elastic contact with the inner peripheral surface of the workpiece hole 2 to seal the workpiece hole 2. Also, as shown in FIG.
The relationship between the outer diameter of the ring 4 in normal times and the inner diameter of the work hole 2 is set.

A leak test of the work 1 is performed in the state shown in FIG. 1B, and when the leak test is completed, the cylindrical pressing body 7 is retracted to the original rear position. As a result, the O-ring 4 returns to the normal state shown in FIG. 1A due to the elastic return force, and the sealing jig 3 is pulled out of the work hole 2 in this state. Also at this time, the O-ring 4 is pulled out of the work hole 2 without being rubbed against the inner peripheral surface of the work hole 2.

As described above, when the seal jig 3 is inserted into and removed from the work hole 2, the O-ring 4 does not rub against the inner peripheral surface of the work hole 2, and even if rubbed, the O-ring 4 slides lightly. Wear of the O-ring 4 is reduced, and the frequency of replacement of the O-ring 4 is greatly reduced. In fact, when the O-ring replacement frequency was compared and investigated under the same conditions as that of the conventional product in FIG. O-ring exchange was finally required after a leak test of a certain degree. That is, the O of the present invention
It has been found that the life of the ring is extended about four times that of the conventional product. In addition, when the seal jig 3 is inserted into and removed from the work hole 2, the O-ring 4 does not strongly rub against the inner peripheral surface of the work hole 2, so that the frictional resistance when the seal jig 3 is inserted and removed is reduced.
The workability of inserting and removing the sealing jig is improved.

In the embodiment shown in FIGS. 2A and 2B, the tip end surface n of the cylindrical pressing body 7 is formed as a conical tapered pressing surface n 'that expands the inner diameter R of the O-ring 4. Things. The tapered pressing surface n 'is a conical surface extending rearward from the distal end of the cylindrical pressing body 7, and in an ordinary state, as shown in FIG. Contact so that it bites into the inside diameter side of the. When the O-ring 4 is pressed by moving the cylindrical pressing body 7 forward with respect to the jig main body 5 in this state, as shown in FIG.
Presses the O-ring 4 so as to widen the inner diameter R ′ of the O-ring 4 to increase the outer diameter of the O-ring 4. Therefore, O-ring 4
The O-ring 4 more reliably and firmly makes elastic contact with the inner peripheral surface of the work hole 2 to seal the work hole 2.

Incidentally, similarly to the tapered pressing surface n 'of the cylindrical pressing member 7, the step surface m of the convex step portion 6 may be a conical tapered surface which expands the O-ring 4 from the inner diameter side. Alternatively, only the stepped surface m may be a conical tapered surface that expands the O-ring 4 from the inner diameter side.

In the embodiment shown in FIGS. 3A and 3B, the cylindrical pressing member 7 is retracted by the spring member 10. FIG. In this case, the jig main body 5 is cylindrical, and the drive shaft 11 is internally provided.
Are inserted movably in the axial direction, and the drive shaft 11 and the cylindrical pressing body 7 are integrally connected by the connecting pin 12. The spring material 10 compressed in the axial direction is mounted between the drive shaft 11 and the jig body 5. The spring member 10 constantly urges the drive shaft 11 rearward so that the drive shaft 11 and the drive shaft 11 are in a normal position where the tubular pressing body 7 is lightly in contact with the O-ring 4 as shown in FIG. The pressing body 7 is held.

When the sealing jig 3 is inserted into the work hole 2 in the state shown in FIG. 3A, the drive shaft 11 is automatically or manually advanced with respect to the jig main body 5 as shown in FIG. 3B. Move. As a result, the spring member 10 is compressed, the drive shaft 11 moves forward, the cylindrical pressing body 7 moves forward via the connecting pin 12, compresses the O-ring 4, and expands the outer diameter of the O-ring 4 to increase the work hole. 2 is brought into elastic contact. When the external force for moving the drive shaft 11 forward is released, the drive shaft 11, the connecting pin 12, and the cylindrical pressing body 7 automatically return to their original normal positions by the elastic force of the spring member 10.

[0022]

According to the seal jig of the first aspect, the outer diameter of the O-ring when the seal jig is inserted into and removed from the work hole is smaller than the inner diameter of the work hole. The ring is not rubbed by the work hole. Therefore, the wear of the O-ring is greatly reduced, the life of the O-ring can be extended, and the frequency of replacement of the O-ring can be greatly reduced. Further, since the O-ring does not rub against the work hole when the seal jig is inserted into and removed from the work hole, the frictional resistance when inserting and removing the seal jig is reduced, and the workability of inserting and removing the seal jig is improved. .

According to the second aspect of the present invention, at least one of the cylindrical pressing member for pressing the O-ring to expand the diameter and the convex step portion is a taper pressing surface for expanding the O-ring from the inner diameter side. In addition, the diameter of the O-ring can be increased, and a highly reliable sealing jig that reliably seals the work hole can be provided.

[Brief description of the drawings]

FIGS. 1A and 1B are partial cross-sectional views of a sealing jig showing a first embodiment of the present invention. FIG.
FIG. 4 is a sectional view when a work hole is sealed.

FIGS. 2A and 2B are partial cross-sectional views of a sealing jig showing a second embodiment of the present invention. FIG.
FIG. 4 is a sectional view when a work hole is sealed.

FIGS. 3A and 3B are partial cross-sectional views of a sealing jig showing a third embodiment of the present invention. FIG.
FIG. 4 is a sectional view when a work hole is sealed.

4A and 4B are partial cross-sectional views of a conventional sealing jig. FIG. 4A is a cross-sectional view before insertion into a work hole, and FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Work 2 Work hole 3 Seal jig 4 O-ring 5 Jig main body 6 Convex step 7 Cylindrical pressing body n 'Taper pressing surface

Claims (2)

[Claims] 1. A sealing jig which is inserted into a work hole formed in a work to be subjected to a leak test and seals the work hole by elastically contacting an elastic O-ring with an inner peripheral surface of the work hole. An axial jig main body for fitting an O-ring having an outer diameter smaller than the hole diameter of the hole to the outer periphery of the tip end; A protruding step having at the rear end a step surface with which the O-ring fitted to the jig body comes into contact; and a tip surface facing the O-ring, which is slidably fitted in the outer periphery of the jig body in the axial direction. And a cylindrical pressing body having an outer diameter smaller than the outer diameter of the O-ring. The cylindrical pressing body is moved forward to the protruding step side, and the O-ring is pressed against the step surface of the protruding step by the distal end surface of the cylindrical pressing body. And, sealing jig elastic O-ring in the pressing force to compress so as to expand its outer diameter, and wherein the to repression contact diameter was O-ring on the inner peripheral surface of the workpiece bore. 2. The method according to claim 1, wherein at least one of the distal end surface of the cylindrical pressing body and the step surface of the convex step is pressed so that the inner diameter of the O-ring is enlarged when the O-ring is pressed against the convex step by the cylindrical pressing body. 2. The seal jig according to claim 1, wherein the ring has a conical taper pressing surface for pressing from the inner diameter side.