JP4798332B2 - Resin pipe connection structure - Google Patents

Description

  The present invention relates to a resin pipe connection structure.

  Conventionally, when connecting a resin pipe to a metal pipe, for example, the end of the metal pipe is subjected to bulge processing or spool processing (processing to create an enlarged portion on the outer peripheral surface with a substantially constant thickness). It was made to press-fit in the form of extrapolating the resin tube.

  In the connection state in which the resin pipe is press-fitted into the metal pipe processed as described above, the resin pipe is expanded at the diameter-expanded portion of the metal pipe to tighten the resin diameter reducing action (action to restore). The fluid tightness is ensured by the applied force.

However, in the conventional resin pipe connection structure, the tightening force decreases due to aging such as thermal deterioration of the resin pipe, so that fluid tightness between the resin pipe and the metal pipe cannot be secured, and as a result, relatively short-term There is a problem that fluid may leak between the two.
JP-A-9-126374 (see FIG. 5)

  Accordingly, an object of the present invention is to provide a resin pipe connection structure in which fluid does not leak for a long period of time.

The resin pipe connection structure according to the present invention includes a metal pipe having an enlarged diameter portion at a position away from the tip, and a tapered portion formed on the other end side through an upright wall from an insertion portion formed on one end side. together and a color made by the insertion portion of the collar and the inner insert at the tip of the metal pipe, there the insertion portion outer peripheral surface as an insertion state of being in close contact with the inside metal pipe circumference, also, the insertion portion A circumferential projection is formed at a position on the outer circumferential surface away from the distal end of the insertion portion, and the circumferential projection and the circumferential concave portion on the inner surface side of the constituent wall of the enlarged diameter portion are in a locked state so that the collar is removed from the metal pipe. Is in a state of being prevented from coming off and in the insertion state from the tip of the metal pipe to a position exceeding the enlarged diameter portion , the metal pipe and the collar portion in the insertion state are cut off. Expansion of vertical walls and metal pipes Characterized in that the interval between sets each other as a double circumferential groove and the metal pipe and the collar in close contact engages housing the sealing ring to the peripheral groove, are a resin tube is pressed to a position beyond said seal ring And
In the inserted state of the connection structure of the resin tube, the insertion portion of the collar, than the larger diameter portion of the metal pipe to a position on the back side Ri Oh and inner insert remains the same diameter, and a metal pipe tip It is in contact with the collar wall .

Further, the resin pipe connection structure of the present invention is the resin pipe connection structure, wherein a circumferential projection is formed at a position away from the distal end of the insertion portion on the outer circumferential surface of the insertion portion , and the circumferential projection and the enlarged diameter The peripheral recess on the inner surface side of the wall is in a locked state, the collar is in a state of being prevented from coming off from the metal pipe , and is inserted from the tip of the metal pipe to the position exceeding the enlarged diameter portion. Yes .

Further, in any one of the resin pipe connection structures, the enlarged diameter portion of the metal pipe is formed by spool processing, so that the inner surface of the constituent wall formed when the enlarged diameter portion is formed is opposed to the circumferential recess. In the locked state, the circumferential protrusion of the insertion portion is sandwiched and locked between the inner surfaces of the constituent walls in contact with each other.

The insertion portion 20 is formed with a slit in the length direction .

Further, the resin pipe connection structure of the present invention relates to any one of the above- described inventions, and an enlarged diameter portion serving as a stopper for the insertion end of the press-fitted resin pipe is provided on the back side of the enlarged diameter portion constituting the circumferential groove. It is provided.

In addition, the resin pipe connection structure according to the present invention relates to any one of the above- described inventions, and is provided with an expansion for increasing the strength against the disconnection of the resin pipe from the metal pipe on the rear side of the enlarged diameter portion constituting the circumferential groove. A diameter portion is provided.

  According to the resin pipe connection structure of the present invention, fluid does not leak for a long period of time.

  In the following, an embodiment as the best mode for carrying out the resin pipe connection structure of the present invention will be described in detail.

  FIG. 1 is a half sectional view of a connecting structure of a resin pipe 3 in Embodiment 1 of the present invention. FIG. 2 is a sectional view of a state in which a seal ring SR and a buckling BR are accommodated in a circumferential groove 12 formed in the connecting structure. FIG. 3 is a sectional view showing a state in which the inner diameter of the collar 2 and the inner diameter of the resin tube 3 are matched in the connection structure.

(About this resin pipe connection structure)
As shown in FIG. 1, the resin pipe connection structure has a metal pipe 1 having an enlarged diameter portion 10 at a position away from the tip, and an insertion portion 20 formed on one end side through a vertical wall 21 and the other end side. And a collar 2 in which a tapered taper portion 22 is formed. The insertion portion 20 of the collar 2 is inserted into the tip of the metal pipe 1. In the assembled state, a circumferential groove M is formed between the vertical wall 21 of the collar 2 and the enlarged diameter portion 10 of the metal pipe 1 as shown in FIG. Contained. The resin tube 3 is press-fitted to a position beyond the seal ring SR and the enlarged diameter portion 10 as shown in FIG.

  The metal pipe 1 is made of a metal material such as stainless steel, and the enlarged diameter portion 10 is formed into a shape that rapidly expands from the tip toward the back as shown in FIG. ing. The enlarged diameter portion 10 is formed by spool processing.

  The collar 2 is a cylindrical body made of nylon resin or the like, and as described above, the tapered portion 22 is formed on the other end side from the insertion portion 20 formed on the one end side through the vertical wall 21. A circumferential protrusion 23 is formed on the outer peripheral surface of the insertion portion 20.

  Here, the diameter of the maximum diameter portion of the tapered portion 22 is substantially the same as the diameter of the enlarged diameter portion 10 as shown in FIG.

  Further, when the collar 2 is inserted into the metal pipe 1, the circumferential protrusion 23 is fitted into the circumferential recess 11 formed when the enlarged diameter portion 10 is formed, and the collar 2 is prevented from dropping off from the metal pipe 1. is doing. In the case of adopting such a configuration, it is preferable that a slit is formed in the insertion portion 20 in the length direction in consideration of workability.

  As the resin tube 3, for example, a single-layer or multi-layer structure made of nylon resin or fluorine-based material is employed. Note that. The resin pipe 3 is gradually press-fitted while being expanded in diameter along the taper portion 22 of the collar 2, and maintains the pressure contact state with the seal ring SR and the enlarged diameter portion 10, while the raw tube of the metal pipe 1. The inner diameter is set so as to be in pressure contact with the outer peripheral surface.

The seal ring SR is made of a fluorine material or the like.

(Procedure for connecting resin pipe 3 to metal pipe 1 and collar 2)
First, the seal ring SR is accommodated in the circumferential groove M.

  Next, when the resin tube 3 is press-fitted from the tip of the tapered portion 22 of the collar 2, the resin tube 3 is gradually expanded in diameter along the tapered portion 22, and then the seal ring SR and the expanded diameter portion 10. To the outer peripheral surface of the base pipe of the metal pipe 1.

  In the above state, as described above, the resin tube 3 is in pressure contact with the tapered portion 22, the outer diameter portion of the enlarged diameter portion 10, and the outer peripheral surface of the metal pipe 1, and the resin tube 3 and the metal pipe 1 are sealed. A fluid-tight state is established through the ring SR.

(About the excellent function of the connection structure of the resin pipe 3 to the metal pipe 1)
With this connection structure, even if the tightening force of the resin tube 3 decreases due to aging such as thermal deterioration, the resin tube 3 and the metal pipe 1 are secured in a fluid tight state via the seal ring SR. As a result, the fluid does not leak for a long time.

(About a form similar to this Example 1)
(1) In the circumferential groove M, as shown in FIG. 2, the buckling BR may be accommodated together with the seal ring SR. Thereby, the processing accuracy of the enlarged diameter portion 10 does not affect the airtightness.
(2) As shown in FIG. 3, in order to make the inner diameter R1 of the metal pipe 1 and the inner diameter R2 of the collar 2 coincide or substantially coincide with each other in order to reduce the pipe resistance, the insertion portion of the insertion portion 20 of the collar 2 in the metal pipe 1 May be expanded.
(3) In the above embodiment, the circumferential protrusion 23 is formed on the collar 2, but when the collar 2 without the circumferential protrusion 23 is used, the insertion portion 20 of the collar 2 is inserted into the metal pipe 1. Suppose you have a tight fit.

  FIG. 4 shows a half sectional view of the connection structure of the resin pipe 3 to the metal pipe 1 according to the second embodiment of the present invention.

  The metal pipe 1 in the second embodiment has the enlarged diameter portion 10 of the first embodiment, and further, as shown in FIG. 4, in order to increase the strength against the removal of the resin tube 3 from the metal pipe 1. In addition to the enlarged diameter portion 10 of the first embodiment, an enlarged diameter portion 12 having a cross-sectional mountain shape (a shape that gradually increases in diameter toward the inner side and then gradually decreases in diameter) is provided on the inner side.

Here, in this connection structure, as shown in FIG. 4, the resin tube 3 is press-fitted into the metal pipe 1 until the insertion end reaches the maximum diameter of the enlarged diameter portion 12. The press fitting of the resin pipe 3 into the metal pipe 1 may be performed until it completely exceeds the enlarged diameter portion 12 as shown by a two-dot chain line in FIG.
( Reference example )

FIG. 5 shows a half sectional view of the connection structure of the resin pipe 3 to the metal pipe 1 of the reference example of the present invention.

As shown in FIG. 5, the metal pipe in this reference example is provided with an enlarged diameter portion 13 that gradually increases in diameter toward the back side and then rapidly decreases in diameter, as shown in FIG. 5.

Here, in this reference example , the enlarged diameter portion 10 ′ constituting the circumferential groove M is abruptly enlarged toward the back side so as to constitute the vertical wall 14 and then gradually reduced in diameter. The collar 2 is prevented from falling off the metal pipe 1 by the engagement between the inner surface of the vertical wall 14 and the circumferential protrusion 24 provided at the inner end of the insertion portion 20.

FIG. 6 shows a half sectional view of the connection structure of the resin pipe 3 to the metal pipe 1 according to the third embodiment of the present invention.

In Example 3 , as shown in FIG. 6, the enlarged diameter is formed on the back side of the enlarged diameter portion 10 so that the diameter is rapidly increased from the tip toward the back side, and then is rapidly reduced. A portion 15 is provided, and the enlarged diameter portion 15 functions as a stopper for the insertion end of the resin tube 3. By providing the enlarged diameter portion 15 that functions as a stopper, the press-fitting work of the resin pipe 3 into the metal pipe 1 can be performed with a simple pipe holding jig.

In addition, such an enlarged diameter part 15 can be added to all of the said Examples 1-2 and a reference example .

1 is a half cross-sectional view of a resin pipe connection structure according to Embodiment 1 of the present invention. Sectional drawing of the state which fitted the seal ring and the back ring in the circumferential groove formed in the said connection structure. Sectional drawing of the state which made the internal diameter of the color | collar and the internal diameter of the resin pipe correspond in the said connection structure. The half sectional view of the connection structure to the metal pipe of the resin pipe of Example 2 of this invention. The half sectional view of the connection structure to the metal pipe of the resin pipe of the reference example of this invention. The half sectional view of the connection structure to the metal pipe of the resin pipe of Example 3 of this invention.

SR Seal ring M Circumferential groove 1 Metal pipe 2 Collar 3 Resin pipe 10 Enlarged diameter part 11 Circumferential recess 20 Insertion part 21 Standing wall 22 Taper part 23 Circumferential protrusion

Claims (7)

It is composed of a metal pipe having an enlarged diameter portion at a position away from the tip, and a collar formed by forming a tapered portion on the other end side through an upright wall from an insertion portion formed on one end side,
The insertion portion of the collar is inserted into the tip of the metal pipe, and the insertion portion outer peripheral surface is in close contact with the inner peripheral surface of the metal pipe,
Further, a circumferential projection is formed at a position on the outer circumferential surface of the insertion portion and away from the distal end of the insertion portion, and the circumferential projection and the circumferential concave portion on the inner surface side of the constituent wall of the enlarged diameter portion are in a locked state. The collar is in a state of being prevented from coming off from the metal pipe, and is in the insertion state over a position exceeding the enlarged diameter portion from the tip of the metal pipe.
Of the metal pipe and the collar portion in the inserted state, the circumferential groove is formed as a double circumferential groove in which the metal pipe and the collar are locked and in close contact with each other between the collar's vertical wall and the enlarged diameter portion of the metal pipe. A resin tube connection structure, wherein a seal ring is accommodated in the resin tube and the resin tube is press-fitted to a position exceeding the seal ring. In the inserted state, the insertion portion of the collar is internally inserted with the same diameter up to a position deeper than the enlarged diameter portion of the metal pipe, and the tip of the metal pipe is in contact with the vertical wall of the collar The resin pipe connection structure according to claim 1. Since the enlarged diameter portion of the metal pipe is formed by spool processing, the circumferential recess is configured such that the inner surfaces of the constituent walls formed at the time of forming the enlarged diameter portion are in contact with each other. The resin pipe connection structure according to claim 1 or 2, wherein the circumferential protrusion is sandwiched and locked between inner surfaces of the constituent walls in contact with each other. The resin pipe connection structure according to claim 3, wherein a slit is formed in the length direction in the insertion portion . The resin pipe connection structure according to claim 1, wherein a back ring is accommodated together with the seal ring in the circumferential groove. 6. The resin pipe connection structure according to claim 1, wherein an enlarged diameter portion serving as a stopper at an insertion end of the press-fitted resin tube is provided on the back side of the enlarged diameter portion constituting the circumferential groove. The resin pipe according to any one of claims 1 to 6, wherein a diameter-enlarged portion for increasing the strength against removal of the resin tube from the metal pipe is provided behind the enlarged-diameter portion constituting the circumferential groove. Connection structure.

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