JP4567350B2 - Pipe fitting - Google Patents

Description

  The present invention relates to a pipe joint for fluids, and relates to a pipe joint that facilitates and reliably connects a two-layer pipe having a resin coating on the outer surface of a thin-walled small-diameter metal pipe.

  Conventionally, as a press-type pipe joint for fluid for a two-layer pipe in which the outer surface of a thin-walled small-diameter metal pipe is coated with resin, the one described in WO98 / 11377 shown in FIGS. 4, 5, and 6 is known. It has been.

  However, when the pipe joint 40 of FIG. 4 is used, it is necessary to peel off the resin coating 42 of the two-layer pipe 41, and when the resin coating 42 is peeled off, a blade is used. There is a possibility that the outer surface of the thin metal tube 43 to which the packing hits will be damaged and the fluid may leak. Further, when the resin coating 42 is peeled off, the thin metal tube 43 may be destroyed, and it cannot be said that the construction is easy. In addition, if the resin coating 42 is not completely removed, the resin may remain in the liquid contact portion, and resin fines may be mixed into the fluid. Further, it is necessary to insert a metal reinforcing core 44 at the time of pressing so that the thin metal tube 43 is not deformed more than necessary by the pressing.

  Further, the pipe joint 40 of FIG. 5 has a double-layer pipe 41 inserted into a cylindrical portion 46 with a metal stopper 45, and the end portion 47 of the cylindrical portion 46 is crimped with a tool to obtain a sealing property and at the same time An attempt is made to obtain the pull-out resistance of the tube 41. However, in this method, a fluid enters between the thin metal tube 43 and the resin coating 42 of the two-layer tube 41, which is a factor that promotes peeling of the resin coating 42 from the thin metal tube 43. At the time of construction, there is a method of applying a silicone sealant or the like at the joint between the pipe end of the double-layer pipe 41 and the pipe joint 40 stopper 45 to prevent the ingress of fluid, but this is not perfect. Further, since there is no reinforcing core or the like that prevents the thin metal tube 43 from being deformed more than necessary inside the double-layer tube 41, the double-layer tube 41 is easily squeezed when the double-layer tube 41 is pulled out. There is a fear.

  6, the pipe joint 40 is used as an inner surface seal, the pipe joint 40 is inserted into the two-layer pipe 41, and the outer cylinder 48 is fitted to the outside of the two-layer pipe 41 so that the caulking and outer cylinder 49 are fitted. The packing 49 provided at the tip of the two-layer pipe 41 and the pipe joint 40 is pressed to deform the outer cylinder 48 so as to obtain a sealing property and a pull-out preventing force. However, with this structure, a large pulling-in preventing force cannot be obtained, and the pull-out resistance is inferior.

Japanese Patent Application Laid-Open No. 2001-295974 discloses that a pipe joint is tightened with a joint body provided with a tapered protrusion on an insertion tube portion inserted into an end portion of the tube and a concave circumferential groove for mounting a sealing material. An annular body is disclosed in which when a tube is inserted into an insertion cylinder and a tightening ring is attached, a tapered protrusion on the insertion cylinder bites into the inner surface of the pipe to prevent the tube from coming off. ing. However, with such sharp tapered protrusions, when a thin double-layer pipe with a resin coating is attached to the outer surface of a thin-walled small-diameter metal pipe, the thin metal pipe is cracked, and the inherent performance of the double-layer pipe You may not be able to demonstrate.
WO98 / 11377 (FIGS. 1, 2 and 3) JP 2001-295974 A (0014, FIG. 1)

  Accordingly, the present invention provides a two-layer tube in which the outer surface of a thin-walled small-diameter metal tube is coated with a resin, and preferably the outer surface of a thin-walled metal tube having a thickness of about 0.08 mm to 0.2 mm. Providing a press-type pipe joint that is a joint for a two-layer pipe having an outer diameter of about 14 mm to 30 mm, that is easy to connect, has a reliable sealing property, and has a high pull-out resistance. It is the purpose.

  In addition, the present invention provides a guide function that makes it possible to visually confirm that the double-layer pipe to be connected is securely inserted, and to keep the press position relative to the pipe joint by a tool, An object of the present invention is to provide a press-type pipe joint in which there is no shortage.

  Another object of the present invention is to provide a press-type pipe joint that prevents the metal pipe from being damaged when the metal pipe of the connected double-layer pipe is deformed by the press.

  Another object of the present invention is to provide a press-type pipe joint that prevents the sealing material from being damaged by the press and facilitates the mounting of the sealing material.

The configuration of the present invention for achieving the above object is to provide an inner tube portion projecting from a joint body having an outer diameter capable of fitting a two-layer tube having a resin coating on the outer surface of a thin-walled small-diameter metal tube. A sealing material mounted in a groove on the outer surface of the inner cylinder, a number of angled irregularities having a smooth curved surface continuously provided on the outer surface of the inner cylinder, a ring locked to the joint body, An outer cylinder portion held by the ring, and when the outer cylinder portion is pressed from the outside in a state where the two-layer tube is inserted between the inner cylinder portion and the outer cylinder portion, A metal tube inside the two-layer tube is pressed by the inner cylinder portion, the sealing material, and the uneven portion, and the metal tube of the two-layer tube is deformed along the uneven portion of the inner cylinder portion .

Further, the present invention provides a pipe joint according to the preceding paragraph , wherein a window portion is provided on the side of the ring that is locked to the base end side of the joint body in order to hold the outer cylinder portion, and a double-layer pipe can be visually observed. Is made larger than the outer diameter of the outer cylinder portion.

  Further, the present invention provides the pipe joint according to any one of the preceding paragraphs or the preceding paragraphs, wherein the peak of the chevron-shaped uneven part and the valley part on the outer surface of the inner cylinder part have an obtuse angle exceeding 100 degrees, and the top part of the uneven part. Is a smooth curved surface.

  Further, according to the present invention, in the pipe joint according to any one of the preceding paragraphs to the preceding paragraph, the groove of the inner cylinder portion to which the sealing material is attached has a cross section whose groove bottom is parallel to the tube axis, and the wall portion is The pipe shaft has a vertical surface, and the wall on which the sealing material is pressed by the pressure of the fluid is a curved surface starting from the point where the perpendicular drawn from the center of the cross section of the sealing material intersects the wall and then outwards. The wall surface directly opposite to the wall surface to be pressed is a curved surface that starts slightly inside from the center of the cross section of the sealing material and continues to the outer surface of the inner cylinder part.

  With the above configuration, the present invention inserts the double-layer tube inside the outer tube portion so that the inner tube portion is inserted inside the double-layer tube, and presses it with a tool from above the outer tube portion. The inner surface of the double-layer tube presses the sealing material to ensure sealing performance, and the metal tube of the double-layer tube deforms along the chevron-shaped uneven portion of the inner cylinder, thereby obtaining a high pull-out resistance. be able to.

  Further, according to the present invention, the double-layer pipe is securely inserted by providing a window portion on the side surface of the ring that is locked to the joint body to hold the outer cylinder portion so that the double-layer pipe can be visually observed. In addition to being able to confirm this visually, it is possible to provide a guide function for keeping the press position relative to the joint by the press tool by applying the side of the press tool to the end of the ring. By making the outer diameter of the ring larger than the opening interval of the press tool in the outer cylinder portion, insufficient tightening due to the tool biting the ring can be prevented.

  Then, the present invention provides two layers to be connected if the opening angle of the top and bottom of the chevron-shaped uneven part on the outer surface of the inner cylinder part is an obtuse angle exceeding 100 degrees, and the top part of the uneven part is a smooth curved surface. The metal tube is not damaged when the metal tube is deformed by pressing.

  According to the present invention, the groove of the inner cylinder portion to which the sealing material is mounted has a cross section whose parallel to the tube axis is the bottom of the groove, and the wall portion is perpendicular to the tube axis. The wall on which the sealing material is pressed is a curved surface starting from the point where the perpendicular drawn to the wall from the center of the cross section of the sealing material intersects, and the wall directly opposite the wall on which the sealing material is pressed by the pressure is from the center of the cross section of the sealing material By making a curved surface that starts from the inside and continues to the outer surface of the inner cylinder, it becomes a sealing material when a double-layer pipe is inserted or when a small amount of the sealing material moves or deforms due to the internal pressure of the double-layer pipe. It is possible to prevent damage and to easily attach the sealing material to the inner cylinder portion.

  Embodiments of the present invention will be described below with reference to the drawings.

  In the example shown in FIG. 1, an inner cylinder portion 6 having an outer diameter that can fit a two-layer pipe 5 having a resin coating 4 on the outer surface of a thin metal pipe 3 is protruded from a joint body 1 via a stepped portion 2. A number of grooves 7 are provided at appropriate locations on the inner cylinder 5, and a sealing material 8 is attached to the grooves 7, and the outer cylinder 6 has a gently curved surface on the outer surface of the step 2. A mountain-shaped uneven portion 9 is continuously provided. A ring 11 provided with a window portion 10 on the side surface where the insertion of the two-layer pipe 3 can be visually observed is pivotally locked behind the step portion 2 of the joint body 1. An outer cylinder portion 12 that is externally fitted to the double-layer tube 5 is held.

  The double-layered tube 5 is preferably a thin metal tube 3 having a thickness of about 0.08 mm to 0.2 mm and having an outer diameter of about 14 mm to 30 mm.

  The outer diameter of the ring 11 is formed to be slightly larger than the opening interval of the press tool 13 of the outer cylinder portion 12 of the joint body 1, and when the press tool 13 presses the outer cylinder portion 12, the press tool 13 11 is prevented from being bitten by the press tool 13 so that the ring 11 does not bite, and the side of the press tool 13 is applied to the end of the ring 11 so that the press tool 13 A guide function is provided to keep the press position relative to the pipe joint constant.

  Further, the opening angle of the top and bottom of the chevron-shaped uneven part 9 on the outer surface of the inner cylinder part 6 of the joint body 1 is an obtuse angle exceeding 100 degrees, and the top part of the uneven part 9 is a smooth curved surface and is connected. When the metal tube 3 of the double-layer tube 5 is deformed by pressing, consideration is given so that the metal tube 3 is not damaged.

  Further, the groove 7 of the inner cylinder part 6 of the joint body 1 to which the sealing material 8 is mounted has a cross section whose groove bottom part is parallel to the pipe axis, and whose wall part is perpendicular to the pipe axis. The wall on which the sealing material 8 is pressed by the pressure of the surface is a curved surface starting from the point where the perpendicular drawn from the center of the cross section of the sealing material 8 intersects the wall, and the wall directly opposite the wall on which the sealing material 8 is pressed by the pressure Has a curved surface that starts slightly inside from the center of the cross-section of the sealing material 8 and continues to the outer surface of the inner cylindrical portion 6 of the joint body 1. By doing so, the two-layer tube 5 is inserted when the two-layer tube 5 is inserted. When the sealing material 8 is moved and deformed in a small amount by the internal pressure 5, the sealing material 8 is prevented from being damaged and the sealing material 8 is attached to the inner tube portion 6 of the joint body 1. So that can be done to ease.

  Next, the use of this pipe joint will be described with reference to FIGS.

  First, the double-layer pipe 5 is inserted until it is fitted on the inner cylinder portion 5 of the joint body 1 and is in contact with the step portion 2 so as to be fitted on the outer cylinder portion 12 of the joint body 1. At this time, it is inserted from the window portion 10 of the ring 11 until the tube end portion of the double-layer tube 5 comes into contact with the step portion 2, that is, the double-layer tube 5 is correctly inserted to the press position. Can be visually confirmed. Next, the side surface of the press tool 13 is opened against the end of the ring 11, applied to the outer tube portion 12 of the joint body 1 (see FIG. 2), and the outer tube portion 12 of the joint body 1 is pressed with the press tool 13. . At this time, the metal tube 3 of the double-layer tube 5 is deformed and is in close contact with the inner tube portion 5 of the joint body 1, but the chevron-like uneven portion 9 on the inner surface of the inner tube portion 5 has a gentle curved surface. , There is almost no risk of damaging the metal tube 3 of the double-layer tube 5. In particular, as described above, when the angle of the top and bottom of the chevron-shaped uneven part 9 on the inner surface of the inner cylinder part 5 is an obtuse angle exceeding 100 degrees and the top of the uneven part 9 is a smooth curved surface , There is no fear of damaging the metal tube 3 of the double-layer tube 5, and a high pull-out resistance can be obtained. In the figure, reference numeral 14 denotes a press mark of the outer cylinder portion 12.

  For comparison, the above-mentioned example is attached to both ends of a double-layered tube 5 having a length of 500 mm or more, and a test body in which the above-described chevron-like uneven portion 9 is not provided on the outer surface of the inner cylinder portion 6 is fixed to a test body by a chuck. A pulling test was conducted by applying air pressure of 0.2 MPa and pulling out with an Amsler universal testing machine until leakage occurred. The tensile speed is 2 mm / min. The results are as shown in Table 1, and it was confirmed that a high pull-out resistance was obtained by the above-described chevron-shaped uneven portion 9.

The half sectional view of one example which carried out the present invention. The half cross-sectional view in the state before pressing the outer cylinder part with the example of FIG. 1 with a press tool. The half cross-sectional view in the state which pressed the outer cylinder part with the example of FIG. 1 with the press tool. The half sectional view of the conventional pipe joint. The half sectional view of the conventional pipe joint different from FIG. The half sectional view of the conventional pipe joint different from FIG. 4, FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Joint body 2 Step part 3 Metal pipe 4 Resin coating 5 Double-layer pipe 6 Inner cylinder part 7 Groove
8 Sealing material
9 Uneven part of Yamagata
10 windows
11 Ring 12 Outer tube
13 Press tool 14 Press mark

40 Pipe joint 41 Double-layer pipe 42 Resin coating 43 Thin metal pipe 44 Reinforcement core 45 Stopper 46 Tube portion 47 End portion of tube portion 48 Outer tube 49 Packing

Claims (4)

An inner cylinder projecting from a joint body with an outer diameter that can fit a two-layer pipe with a resin coating on the outer surface of a thin-walled small-diameter metal tube, and a seal mounted in a groove on the outer surface of the inner cylinder A plurality of chevron-shaped irregularities having a smooth curved surface continuously provided on the outer surface of the inner cylinder part, a ring locked to the joint body, and an outer cylinder part held by the ring ,
When the outer tube portion is pressed from the outside in a state where the two-layer tube is inserted between the inner tube portion and the outer tube portion, the metal tube inside the two-layer tube is moved to the inner tube portion. The pipe joint is characterized in that the metal pipe of the two-layer tube is deformed along the concave and convex portions of the inner cylinder portion by being pressed by the sealing material and the concave and convex portions . A window portion is provided on the side of the ring that is locked to the base end side of the joint body to hold the outer cylinder portion , and the outer diameter of the ring is larger than the outer diameter of the outer cylinder portion. The pipe joint according to claim 1, wherein The pipe joint according to claim 1 or 2, wherein the top and bottom opening angles of the chevron-shaped uneven part on the outer surface of the inner cylinder part are obtuse angles exceeding 100 degrees, and the top part of the uneven part is a smooth curved surface. The groove of the inner cylinder part to which the sealing material is mounted has a cross-section that is parallel to the tube axis at the bottom of the groove, the wall is a surface perpendicular to the tube axis, and the wall surface on which the sealing material is pressed by the fluid pressure Is a curved surface that starts from the point where the perpendicular drawn from the center of the cross section of the sealing material intersects to the outside, and the wall directly opposite the wall on which the sealing material is pressed by the pressure starts slightly inside from the center of the cross section of the sealing material. The pipe joint according to any one of claims 1 to 3, wherein the pipe joint is formed into a curved surface that is continuous with the outer surface of the cylindrical portion.