JP4211078B2

JP4211078B2 - Piping connection structure

Info

Publication number: JP4211078B2
Application number: JP04054998A
Authority: JP
Inventors: 竜雄杉本; 聡美武藤; 高明阪根
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 1998-02-23
Filing date: 1998-02-23
Publication date: 2009-01-21
Anticipated expiration: 2018-02-23
Also published as: JPH11236985A

Description

【０００１】
【発明の属する技術分野】
本発明は、樹脂製の配管を金属製の配管内に挿入接続する配管の接続構造に関するものであり、エンジン冷却水が流通する配管の接続に適用して有効である。
【０００２】
【従来の技術】
配管の接続構造として、例えば特開平６−６６３９２号公報では（図７参照）、一方側の金属製の配管１にフランジ部Ａを形成するとともに、他方側の金属製の配管２にフランジ部Ａを覆うように拡管部Ｂを形成し、ＯリングＣをフランジ部と拡管部Ｂとの間に配設した状態で拡管部の一部を配管１の径内方側に向けて塑性変形させて、両配管１、２をカシメ固定している。
【０００３】
したがって、上記公報に記載の配管の接続構造は、フランジ部Ａの円環平面と拡管部の内面との隙間をＯリングＣにて密閉する平面固定型の密閉構造を構成しているので、ＯリングＣにおける密閉性を維持するには、フランジ部Ａの円環平面と拡管部の内面との距離を所定範囲内に維持する必要がある。
【０００４】
【発明が解決しようとする課題】
ところで、発明者等は、配管等の製造原価低減を図るべく、配管の樹脂化を検討していたところ、上記公報に記載の配管の接続構造では、以下に述べる問題が発生することを発見した。
すなわち、上記公報に記載の配管の接続構造では、フランジ部Ａの円環平面と拡管部の内面との距離を所定範囲内に維持する必要があるため、いずれか一方の配管が他方の配管に対してその軸方向にずれた場合には、Ｏリングにおいて密閉性を確保することができない。
【０００５】
一方、配管１を樹脂製とし配管２を金属製とし、かつ、金属製の配管２の一部を塑性変形させて両配管１、２をカシメ固定した場合には、樹脂製の配管１のクリープ現象（径年変化）に伴う樹脂製の配管１の軸方向寸法の縮小変化により、配管１が配管２に対してその軸方向にずれてしまうこととなる。このため、樹脂製の配管を用いた場合には、Ｏリングで十分な密閉性を確保することができなるという問題が発生する。
【０００６】
本発明は、上記点に鑑み、樹脂製の配管を金属性の配管に接続するのに適した配管の接続構造を提供することを目的とする。
【０００７】
【課題を解決するための手段】
本発明は、上記目的を達成するために、以下の技術的手段を用いる。請求項１〜４に記載の発明では、第１配管（１０）の外周壁と第２配管（２０）の内周壁との間にＯリングを配設するとともに、このＯリング（３０）が配設される溝部（１１）をカシメ部（２４）から所定寸法ずれた位置に位置させたことを特徴とする。
【０００８】
第１に、Ｏリング（３０）が第１配管（１０）の外周壁と第２配管（２０）の内周壁との間に配設されて両配管（１０、２０）間の隙間を密閉しているので、第１配管（１０）が軸方向寸法の縮小変化して、第１配管（１０）が第２配管（２０）に対して軸方向にずれた場合であっても、第１配管（１０）の外周壁と第２配管（２０）の内周壁との距離は変化しない。
【０００９】
第２に、両配管（１０、２０）が互いにカシメ固定された状態において、溝部（１１）がカシメ部（２４）から所定寸法ずれた位置に位置しているので、第１配管（１０）が軸方向にずれた場合であっても、Ｏリング（３０）と第２配管（２０）の内周壁との接触状態を維持することができる。
したがって、本発明に係る配管の接続構造では、クリープ現象により第１配管（１０）が軸方向にずれた場合であっても、Ｏリング（３０）にて十分な密閉性を保持することができる。
【００１０】
さらに、請求項１に記載の発明では、第１配管フランジ部（１２）から溝部（１１）までの距離（ΔＸ）は、円筒部（２２）の軸方向寸法（Ｌ）より小さいことを特徴とする。これにより、第１配管（１０）を第２配管（２０）に挿入する際に発生し得る第１配管（１０）の傾き量を小さくすることができるので、カシメ固定不良およびＯリング（３０）の損傷を未然に防ぐことができる。
また、請求項２に記載の発明では、第１配管（１０）のうちカシメ部（２４）と接触する部位の外径寸法（Ｄ ₁ ）は、溝部（１１）が形成されている部位の外径寸法（Ｄ ₂ ）より小さいことを特徴とする。これにより、カシメ部（２４）のカシメ代を大きくすることができるので、確実に両配管（１０、２０）をカシメ固定することができる。
【００１１】
なお、請求項３に記載の発明のごとく、第１配管（１０）が第２配管（２０）に対して回転することを防止する回転防止部（４０）を設けてもよい。
そして、回転防止部（４０）は、請求項４に記載の発明のごとく、カシメ部（２４）と係合する突起部（１４）を第１配管（１０）の外周壁に形成することにより構成してもよい。
【００１３】
なお、上記各手段の括弧内の符号は、後述する実施形態記載の具体的手段との対応関係を示すものである。
【００１４】
【発明の実施の形態】
（第１実施形態）
本実施形態は、本発明に係る配管の接続構造をエンジン冷却水が流通する配管の接続に適用したものであり、図１は本実施形態に係る配管の接続構造を示す断面図であり、図２は配管の接続構造を示す外観図である。
【００１５】
図１中、１０は樹脂製の配管（以下、樹脂管と呼ぶ。）であり、２０は金属製の配管（以下、金属管と呼ぶ。）である。そして、樹脂管１０の外周壁と金属管２０の内周壁との間には、両管１０、２０間の隙間を密閉するニトリルゴム製のＯリング３０が配設されており、このＯリング３０は、樹脂管１０の外壁のうち金属管２０内に挿入される部位に形成された溝部１１内に配設されている。
【００１６】
また、金属管２０のうち樹脂管１０側（紙面右側）の端部には、図３に示すように、金属管２０の円周方向全域に渡ってその径外方側に延出するフランジ部２１（第２配管フランジ部）、およびフランジ部２１の外縁部から樹脂管１０側に延出する円筒状の円筒部２２が一体成形されており、この円筒部２２には、円周方向に延びるように円筒部２２の一部を切断削除したスリット部２３が複数個（本実施形態では４個）形成されている。
【００１７】
一方、樹脂管２０には、図１、４に示すように、フランジ部２１に接触するとともに、樹脂管２０の円周方向全域に渡ってその径外方側に延出するフランジ部１２（第１配管フランジ部）が一体成形されている。そして、この樹脂管１０のフランジ部１２を金属管２０のフランジ部２１に接触させた状態で、図２に示すように、スリット部２３が形成された円筒部２２を樹脂管１０の径内方側に向けて略くの字状に塑性変形させることにより、樹脂管１０を金属管２０にカシメ固定するカシメ部２４を形成している。
【００１８】
ところで、溝部１１は、図３に示すように、両管１０、２０が互いにカシメ固定された状態において、カシメ部２４から所定寸法ずれた位置に位置させるべく、樹脂管１０のフランジ部１２から金属管２０側に所定の距離ΔＸずれた位置に形成されており、この距離ΔＸは、円筒部２２の軸方向寸法Ｌより小さくなるように設定されている。
【００１９】
なお、円筒部２２の軸方向寸法Ｌとは、図３から明らかなように、金属管２０のフランジ部２１のうち樹脂管１０のフランジ部１２との接触面から円筒部２２の軸方向端部までの寸法をいう。
次に、本実施形態の特徴を述べる。
第１に、Ｏリング３０が樹脂管１０の外周壁と金属管２０の内周壁との間に配設されて両管１０、２０間の隙間を密閉しているので、樹脂管１０が軸方向寸法の縮小変化して、樹脂管１０が金属管２０に対して軸方向にずれた場合であっても、樹脂管１０の外周壁と金属管２０の内周壁との距離は変化しない。
【００２０】
第２に、両管１０、２０が互いにカシメ固定された状態において、溝部１１がカシメ部２４から所定寸法ずれた位置に位置しているので、樹脂管１０が軸方向にずれた場合であっても、そのずれ量が距離ΔＸ内であれば、Ｏリング３０と金属管２０の内周壁との接触状態を維持することができる。
したがって、本実施形態に係る配管の接続構造では、クリープ現象により樹脂管１０が軸方向にずれた場合であっても、Ｏリング３０にて十分な密閉性を保持することができる。
【００２１】
ところで、本実施形態に係る配管の接続構造は、樹脂管１０を金属管２０に挿入した後に、両管１０、２０をカシメ固定するものであるので、樹脂管１０を金属管２０に挿入する際に、図４に示すように、樹脂管１０が金属管２０に対して傾く可能性が高い。
そして、樹脂管１０が傾いたままカシメ固定を行うと、カシメ部２４と樹脂管１０との接触部の面圧が不均一になり、カシメ固定不良を招くとともに、樹脂管１０を金属管２０に挿入する際に両管１０、２０間にＯリング３０が噛み込み、Ｏリング３０が損傷するおそれが高い。
【００２２】
これに対して、本実施形態では、距離ΔＸが軸方向寸法Ｌより小さくなるように設定されているので、樹脂管１０を金属管２０に挿入する際に発生し得る樹脂管１０の傾き量θを小さくすることができる。したがって、カシメ固定不良およびＯリング３０の損傷を未然に防ぐことができる。
ところで、本実施形態では、図１に示すように、樹脂樹脂管１０のうちカシメ部２４と接触する部位の外径寸法Ｄ₁が、溝部１１が形成されている部位の外径寸法Ｄ₂より小さくなるように構成されているので、カシメ部２４のカシメ代ｄを大きくすることができる。したがって、確実に両管１０、２０をカシメ固定することができる。
【００２３】
（第２実施形態）
本実施形態は、図５に示すように、樹脂管１０が金属管２０に対して回転することを防止する回転防止部４０を設けたものである。
具体的には、金属管２０の一部を径内方側に向けて潰すことにより、金属管２０を非円筒状とするＶ突起部（転防止部）２５を形成とともに、樹脂管１０のうちＶ突起部２５に対応する部位にＶ突起部２５と係合するＶ溝部（回転防止部）１３を形成したものである。
【００２４】
これにより、樹脂管１０が金属管２０に対して回転することを防止できるとともに、樹脂管１０を金属管２０に対して容易に位置決めすることができるので、Ｏリング３０の耐久性（信頼性）を向上させることができる。
（第３実施形態）
本実施形態は、図６に示すように、略くの字状のカシメ部２４と係合する突起部１４を樹脂管１０の外周壁に形成することにより、回転防止部４０を構成したものである。
【００２５】
とことで、上述の実施形態では、樹脂管１０に溝部１１を設けたが、金属管２０に溝部１１を設けても本発明を実施することができる。
また、本発明は、エンジン冷却水が流通する配管の接続構造にその適用が限定されるものではなく、その配管の接続にも適用することができる。
【図面の簡単な説明】
【図１】第１実施形態に係る配管の接続構造を示す断面図である。
【図２】第１実施形態に係る配管の接続構造を示す外観図である。
【図３】第１実施形態に係る配管の接続構造を示す断面図である。
【図４】第１実施形態に係る配管の接続構造を示す断面図である。
【図５】第２実施形態に係る配管の接続構造を示す断面図である。
【図６】第３実施形態に係る配管の接続構造を示す断面図である。
【図７】従来の技術に係る配管の接続構造を示す断面図である。
【符号の説明】
１０…樹脂管（第１配管）、１１…溝部、
１２…フランジ部（第１配管フランジ部）、２０…金属管（第２配管）、
２１…フランジ部（第２配管フランジ部）、２２…円筒部、
２３…スリット部、２４…カシメ部、３０…Ｏリング。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pipe connection structure for inserting and connecting a resin pipe into a metal pipe, and is effective when applied to a pipe connection through which engine coolant flows.
[0002]
[Prior art]
As a pipe connection structure, for example, in JP-A-6-66392 (see FIG. 7), a flange portion A is formed on one metal pipe 1 and a flange portion A is formed on the other metal pipe 2. The expanded portion B is formed so as to cover, and a part of the expanded portion is plastically deformed toward the radially inner side of the pipe 1 with the O-ring C disposed between the flange portion and the expanded portion B. Both pipes 1 and 2 are fixed by caulking.
[0003]
Therefore, the pipe connection structure described in the above publication constitutes a fixed plane type sealing structure in which the gap between the annular plane of the flange portion A and the inner surface of the expanded portion is sealed by the O-ring C. In order to maintain the sealing performance in the ring C, it is necessary to maintain the distance between the annular plane of the flange portion A and the inner surface of the expanded portion within a predetermined range.
[0004]
[Problems to be solved by the invention]
By the way, the inventors have been studying resinization of piping in order to reduce the manufacturing cost of piping and the like, and found that the following problems occur in the piping connection structure described in the above publication. .
That is, in the pipe connection structure described in the above publication, since it is necessary to maintain the distance between the annular plane of the flange part A and the inner surface of the pipe expansion part within a predetermined range, one of the pipes becomes the other pipe. On the other hand, when it deviates in the axial direction, the O-ring cannot secure the hermeticity.
[0005]
On the other hand, when the pipe 1 is made of resin, the pipe 2 is made of metal, and both the pipes 1 and 2 are caulked and fixed by plastic deformation of a part of the metal pipe 2, the creep of the resin pipe 1 The pipe 1 is displaced in the axial direction with respect to the pipe 2 due to a reduction in the axial dimension of the resin-made pipe 1 due to the phenomenon (diametrical change). For this reason, when resin piping is used, there arises a problem that sufficient sealing performance cannot be secured by the O-ring.
[0006]
An object of this invention is to provide the connection structure of piping suitable for connecting resin piping to metal piping in view of the said point.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention uses the following technical means. In the invention according to claims 1 to 4 , an O-ring is disposed between the outer peripheral wall of the first pipe (10) and the inner peripheral wall of the second pipe (20), and the O-ring (30) is disposed. The groove (11) to be provided is located at a position displaced by a predetermined dimension from the crimping portion (24).
[0008]
First, an O-ring (30) is disposed between the outer peripheral wall of the first pipe (10) and the inner peripheral wall of the second pipe (20) to seal the gap between the two pipes (10, 20). Therefore, even if the first pipe (10) is reduced in axial dimension and the first pipe (10) is displaced in the axial direction with respect to the second pipe (20), the first pipe The distance between the outer peripheral wall of (10) and the inner peripheral wall of the second pipe (20) does not change.
[0009]
Secondly, in a state where both the pipes (10, 20) are fixed by caulking, the groove (11) is located at a position shifted by a predetermined dimension from the caulking part (24), so the first pipe (10) is Even when it is shifted in the axial direction, the contact state between the O-ring (30) and the inner peripheral wall of the second pipe (20) can be maintained.
Therefore, in the pipe connection structure according to the present invention, even when the first pipe (10) is displaced in the axial direction due to a creep phenomenon, the O-ring (30) can maintain a sufficient hermeticity. .
[0010]
Furthermore, in the invention described in claim 1 , the distance (ΔX) from the first piping flange portion (12) to the groove portion (11) is smaller than the axial dimension (L) of the cylindrical portion (22). To do. Thereby, since the amount of inclination of the 1st piping (10) which may be generated when inserting the 1st piping (10) into the 2nd piping (20) can be made small, caulking fixation failure and O ring (30) Can prevent damage in advance.
Further, in the invention according to claim 2, the outer diameter of the portion in contact crimping portion (24) of the first pipe (10) (D ₁ ) Is the outer diameter dimension (D ₂ ) of the portion where the groove (11) is formed. ) Is smaller. Thereby, since the caulking allowance of a caulking part (24) can be enlarged, both piping (10, 20) can be fixed by caulking reliably.
[0011]
In addition, you may provide the rotation prevention part (40) which prevents that 1st piping (10) rotates with respect to 2nd piping (20) like invention of Claim 3.
And the rotation prevention part (40) is comprised by forming the projection part (14) engaged with the crimping part (24) in the outer peripheral wall of the 1st piping (10) like invention of Claim 4. May be.
[0013]
In addition, the code | symbol in the bracket | parenthesis of each said means shows a corresponding relationship with the specific means as described in embodiment mentioned later.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
In the present embodiment, the pipe connection structure according to the present invention is applied to the connection of a pipe through which engine coolant flows, and FIG. 1 is a cross-sectional view showing the pipe connection structure according to the present embodiment. 2 is an external view showing a pipe connection structure.
[0015]
In FIG. 1, 10 is a resin pipe (hereinafter referred to as a resin pipe), and 20 is a metal pipe (hereinafter referred to as a metal pipe). Between the outer peripheral wall of the resin pipe 10 and the inner peripheral wall of the metal pipe 20, a nitrile rubber O-ring 30 that seals the gap between the pipes 10 and 20 is disposed. Is disposed in a groove 11 formed in a portion of the outer wall of the resin tube 10 to be inserted into the metal tube 20.
[0016]
Further, at the end of the metal tube 20 on the resin tube 10 side (right side of the paper), as shown in FIG. 3, a flange portion extending outward in the radial direction over the entire circumferential direction of the metal tube 20. 21 (second piping flange portion) and a cylindrical cylindrical portion 22 extending from the outer edge portion of the flange portion 21 to the resin tube 10 side are integrally formed, and the cylindrical portion 22 extends in the circumferential direction. In this way, a plurality of (four in this embodiment) slit portions 23 are formed by cutting and deleting a part of the cylindrical portion 22.
[0017]
On the other hand, as shown in FIGS. 1 and 4, the resin pipe 20 is in contact with the flange portion 21, and extends to the outer side in the radial direction over the entire circumferential direction of the resin pipe 20 (first flange). 1 piping flange part) is integrally molded. Then, in a state where the flange portion 12 of the resin tube 10 is in contact with the flange portion 21 of the metal tube 20, as shown in FIG. A caulking portion 24 for caulking and fixing the resin tube 10 to the metal tube 20 is formed by plastic deformation in a generally U shape toward the side.
[0018]
By the way, as shown in FIG. 3, the groove portion 11 is formed from the flange portion 12 of the resin tube 10 so as to be positioned at a position shifted by a predetermined dimension from the caulking portion 24 in a state where both the tubes 10 and 20 are fixed by caulking. It is formed at a position shifted by a predetermined distance ΔX on the tube 20 side, and this distance ΔX is set to be smaller than the axial dimension L of the cylindrical portion 22.
[0019]
The axial dimension L of the cylindrical portion 22 is, as is apparent from FIG. 3, the axial end portion of the cylindrical portion 22 from the contact surface of the flange portion 21 of the metal tube 20 with the flange portion 12 of the resin tube 10. The dimensions up to.
Next, features of the present embodiment will be described.
First, since the O-ring 30 is disposed between the outer peripheral wall of the resin tube 10 and the inner peripheral wall of the metal tube 20 and seals the gap between the two tubes 10 and 20, the resin tube 10 is axially Even if the resin tube 10 is displaced in the axial direction with respect to the metal tube 20 due to a reduction in dimensions, the distance between the outer peripheral wall of the resin tube 10 and the inner peripheral wall of the metal tube 20 does not change.
[0020]
Secondly, in a state where both the pipes 10 and 20 are fixed to each other, the groove portion 11 is located at a position shifted by a predetermined dimension from the caulking portion 24, so that the resin pipe 10 is shifted in the axial direction. However, if the deviation amount is within the distance ΔX, the contact state between the O-ring 30 and the inner peripheral wall of the metal tube 20 can be maintained.
Therefore, in the pipe connection structure according to the present embodiment, even when the resin pipe 10 is displaced in the axial direction due to the creep phenomenon, the O-ring 30 can maintain sufficient sealing performance.
[0021]
By the way, since the pipe connection structure according to the present embodiment is to crimp both the pipes 10 and 20 after the resin pipe 10 is inserted into the metal pipe 20, the resin pipe 10 is inserted into the metal pipe 20. In addition, as shown in FIG. 4, there is a high possibility that the resin tube 10 is inclined with respect to the metal tube 20.
If the caulking is performed while the resin tube 10 is tilted, the contact pressure between the caulking portion 24 and the resin tube 10 becomes uneven, causing a caulking improper fixing, and the resin tube 10 is attached to the metal tube 20. There is a high possibility that the O-ring 30 is caught between both the pipes 10 and 20 during the insertion, and the O-ring 30 is damaged.
[0022]
On the other hand, in this embodiment, since the distance ΔX is set to be smaller than the axial dimension L, the amount of inclination θ of the resin tube 10 that may occur when the resin tube 10 is inserted into the metal tube 20. Can be reduced. Therefore, it is possible to prevent the caulking and fixing failure and the O-ring 30 from being damaged.
Incidentally, in the present embodiment, as shown in FIG. 1, the outer diameter D ₁ of the portion in contact with the caulking portion 24 of the resin the resin tube 10, than the outer diameter D ₂ of the portion groove 11 is formed Since it is comprised so that it may become small, the caulking allowance d of the caulking part 24 can be enlarged. Therefore, both pipes 10 and 20 can be securely fixed by caulking.
[0023]
(Second Embodiment)
In the present embodiment, as shown in FIG. 5, a rotation preventing unit 40 that prevents the resin tube 10 from rotating with respect to the metal tube 20 is provided.
Specifically, by crushing a part of the metal tube 20 toward the radially inward side, a V protrusion (roll prevention portion) 25 that makes the metal tube 20 non-cylindrical is formed, and the resin tube 10 A V groove portion (rotation preventing portion) 13 that engages with the V protrusion portion 25 is formed at a portion corresponding to the V protrusion portion 25.
[0024]
Accordingly, the resin tube 10 can be prevented from rotating with respect to the metal tube 20 and the resin tube 10 can be easily positioned with respect to the metal tube 20, so that the durability (reliability) of the O-ring 30 is achieved. Can be improved.
(Third embodiment)
In the present embodiment, as shown in FIG. 6, the rotation preventing portion 40 is configured by forming the protrusion 14 that engages with the substantially square-shaped caulking portion 24 on the outer peripheral wall of the resin tube 10. is there.
[0025]
Thus, in the above-described embodiment, the groove portion 11 is provided in the resin tube 10. However, the present invention can be implemented even if the groove portion 11 is provided in the metal tube 20.
Further, the application of the present invention is not limited to the connection structure of the pipe through which the engine coolant flows, and can also be applied to the connection of the pipe.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a pipe connection structure according to a first embodiment.
FIG. 2 is an external view showing a pipe connection structure according to the first embodiment.
FIG. 3 is a cross-sectional view showing a pipe connection structure according to the first embodiment.
FIG. 4 is a cross-sectional view showing a pipe connection structure according to the first embodiment.
FIG. 5 is a cross-sectional view showing a pipe connection structure according to a second embodiment.
FIG. 6 is a cross-sectional view showing a pipe connection structure according to a third embodiment.
FIG. 7 is a cross-sectional view showing a pipe connection structure according to the prior art.
[Explanation of symbols]
10 ... Resin pipe (first pipe), 11 ... Groove,
12 ... Flange (first piping flange), 20 ... Metal pipe (second piping),
21 ... Flange part (second piping flange part), 22 ... Cylindrical part,
23 ... slit part, 24 ... caulking part, 30 ... O-ring.

Claims

A pipe connection structure for inserting and connecting the first resin pipe (10) into the second metal pipe (20),
An O-ring (30) is disposed between the outer peripheral wall of the first pipe (10) and the inner peripheral wall of the second pipe (20);
A groove (11) in which the O-ring (30) is disposed is formed in one of the pipes (10, 20), and the first pipe (10) is fixed to the second pipe (20) by caulking. A caulking portion (24) to be provided in the second pipe (20),
The groove portion (11) is located at a position shifted by a predetermined dimension from the caulking portion (24) in a state where both the pipes (10, 20) are caulked and fixed to each other .
At the end of the second pipe (20) on the first pipe (10) side, the radially outer side of the second pipe (20) across the entire circumferential direction of the second pipe (20). A second pipe flange portion (21) extending to the second pipe flange portion (21) and a cylindrical cylindrical portion (22) extending from the outer edge portion of the second pipe flange portion (21) to the first pipe (10) side. ,
The caulking part (24) is provided by plastically deforming a part of the cylindrical part (22) toward the radially inner side of the first pipe (10),
On the other hand, the first pipe (10) is in contact with the second pipe flange portion (21) and has a diameter of the first pipe (10) over the entire circumferential direction of the first pipe (10). A first piping flange portion (12) extending outward is formed,
The groove (11) is formed on the outer peripheral wall of the first pipe (10),
Further, the pipe connection structure characterized in that a distance (ΔX) from the first pipe flange part (12) to the groove part (11) is smaller than an axial dimension (L) of the cylindrical part (22) .

A pipe connection structure for inserting and connecting the first resin pipe (10) into the second metal pipe (20),
An O-ring (30) is disposed between the outer peripheral wall of the first pipe (10) and the inner peripheral wall of the second pipe (20);
A groove (11) in which the O-ring (30) is disposed is formed in one of the pipes (10, 20), and the first pipe (10) is fixed to the second pipe (20) by caulking. A caulking portion (24) to be provided in the second pipe (20),
The groove portion (11) is located at a position shifted by a predetermined dimension from the caulking portion (24) in a state where both the pipes (10, 20) are caulked and fixed to each other .
Outer diameter dimension (D ₁ ) of a portion of the first pipe (10) that is in contact with the caulking portion (24). ) Is the outer diameter dimension (D ₂ ) of the portion where the groove (11) is formed. ) Piping connection structure characterized by being smaller .

The pipe connection structure according to claim 1 or 2, further comprising a rotation preventing portion (40) for preventing the first pipe (10) from rotating with respect to the second pipe (20). .

The said rotation prevention part (40) was comprised by forming the protrusion part (14) engaged with the said crimping | crimped part (24) in the outer peripheral wall of the said 1st piping (10). The piping connection structure described in 1.