JP2006322542A - Pipe joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pipe joint for preventing the leakage of fluid to the outside along a joint surface between a cylindrical body and a pipe joint body when pressure is given from fluid flowing inside. <P>SOLUTION: The pipe joint 1 comprises the synthetic resin pipe joint body 2, the metal cylindrical body 3 at least part of which is embedded in the opening end of the pipe joint body 2 and on which a screw is provided, and an outer peripheral wall 33 and an inner peripheral wall 32 extending from the outer peripheral edge and the inner peripheral edge of the corner end face of the cylindrical body 3 to the corner side, respectively. The length of the inner peripheral wall 32 is 50% or more and 100% or less of the length of the outer peripheral wall 33. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pipe joint that connects a synthetic resin pipe and a metal pipe.

  In recent years, pipe joints that connect a synthetic resin pipe and a metal pipe are made of a synthetic resin and a metal. This pipe joint has a structure in which the pipe joint body is made of a synthetic resin, and one of the open ends of the pipe joint body has a structure in which a threaded metal cylinder is embedded. A metal tube can be connected, and a synthetic resin tube can be connected to the other open end.

  In addition, this pipe joint is generally manufactured by insert molding, and the embedded cylinder and the synthetic resin are not joined with an adhesive or the like, and the synthetic resin flows into the concave portion of the cylinder and has an anchor effect. It is integrated by.

  As such a pipe joint, as shown in FIG. 9, an annular recess 301 is formed between the outer protrusion 303 and the inner protrusion 302 at the back end of the cylindrical body 30, and the outer protrusion 303 is provided long. A pipe joint 10 has been proposed (for example, Patent Document 1).

This pipe joint 10 is provided with a long outer protrusion 303, and when the pressure of the fluid flowing in the pipe joint 10 is within a predetermined range, the synthetic resin inside the outer protrusion 303 is transferred to the outer protrusion by the fluid. Since the pressure in the 303 direction is received, the adhesion between the outer protruding portion 303 and the inner synthetic resin can be increased. Due to this increased adhesion, peeling of the joint surface between the cylindrical body 30 and the pipe joint main body 20 can be suppressed, and fluid can be prevented from entering the joint surface.
Japanese Patent Laid-Open No. 10-103569

  However, in this pipe joint 10, the pressure of the fluid flowing in the pipe may become excessively large. In such a case, the pipe joint main body 20 is deformed so as to expand outward from the outer protrusion 303 of the cylindrical body 30. Happens. Due to the expansion, the synthetic resin in the annular recess 301 tends to be deformed inward with the tip of the outer protrusion 303 as a fulcrum. At this time, since the length of the inner protruding portion 302 is short, it is not possible to restrict the synthetic resin in the annular recess 301 from being deformed inward. Therefore, as shown in FIG. 10, the synthetic resin in the annular recess 301 may be deformed by being detached from the inner protrusion 302, and the fluid may easily enter the tip of the protrusion 303.

  Further, due to the expansion of the pipe joint main body 20, a force is applied to the joint surface between the inner peripheral surface of the pipe joint main body 20 and the outer peripheral surface of the cylindrical body 30 in a direction in which the joint surface is peeled off. The pipe joint 10 is provided with a concave groove 304 (see FIG. 9) having a semicircular cross section on the outer peripheral surface of the cylindrical body 30. The concave groove 304 is a force for peeling the pipe joint body 20 from the joint surface. Cannot be stopped, and the outer peripheral surface of the cylindrical body 30 and the inner peripheral surface of the pipe joint body 20 are peeled off. Therefore, the fluid that has reached the tip of the outer protrusion 303 of the cylindrical body 30 easily enters the joint surface between the inner peripheral surface of the pipe joint body 20 and the outer peripheral surface of the cylindrical body 30. In this way, there is a problem that the fluid may leak to the outside of the pipe joint 10.

  The present invention has been made in view of the actual situation, and the purpose thereof is to prevent fluid from leaking to the outside along the joint surface between the tubular body and the pipe joint body when pressure is applied from the fluid flowing inside. It is to provide a pipe joint.

  In order to solve the above problems, a pipe joint of the present invention includes a pipe joint body made of synthetic resin, a metal cylinder body at least partially embedded in an opening end of the pipe joint body, and provided with a screw, In the pipe joint including an outer peripheral wall and an inner peripheral wall extending from the outer peripheral edge and the inner peripheral edge of the rear end surface of the cylindrical body to the rear side, the length of the inner peripheral wall is 50 times the length of the outer peripheral wall. % Or more and 100% or less.

  According to the present invention, the length of the inner peripheral wall is not less than 50% and not more than 100% of the length of the outer peripheral wall. As a result of this expansion, the tip of the outer peripheral wall is pressed outward from the synthetic resin in the annular groove, and the inner peripheral wall is pressed because the synthetic resin in the annular groove tends to deform inward with the tip of the outer peripheral wall as a fulcrum. .

  Therefore, the flow path of the fluid that flows through the joint surface is blocked by the pressure from the synthetic resin in the annular groove to the inner peripheral wall and the pressure from the synthetic resin in the annular groove to the outer peripheral wall. It is possible to prevent leakage to the outside of the joint.

  In addition, when the inner peripheral wall exceeds 50% of the length of the outer peripheral wall, the synthetic resin in the annular groove is deformed when the synthetic resin in the annular groove is deformed inward with the tip of the outer peripheral wall as a fulcrum. Since it does not come off from the peripheral wall, the fluid flow path can be reliably blocked.

  Moreover, when the inner peripheral wall is less than 100% of the length of the outer peripheral wall, the synthetic resin in the annular groove is deformed inwardly with the tip of the outer peripheral wall as a fulcrum. The area for pressing the inner peripheral wall does not increase. Accordingly, the pressure to be pressed is not reduced, and the fluid flow path can be blocked.

  Further, since this pressing force increases according to the expansion amount of the pipe joint body, even if the fluid pressure becomes excessively large, the fluid flow path can be reliably blocked.

  The width of the annular groove formed between the outer peripheral wall and the inner peripheral wall is 20% or more and 70% or less of the thickness from the outer peripheral surface of the outer peripheral wall to the inner peripheral surface of the inner peripheral wall. It may be.

  In this case, since the width of the annular groove is within an appropriate range, the width of the annular groove is narrow, so that the synthetic resin in the annular groove becomes thin, or the width of the annular groove is wide, The synthetic resin in the groove becomes thick, and the pressing force by which the synthetic resin in the annular groove presses the outer peripheral wall and the pressing force by which the synthetic resin in the annular groove presses the inner peripheral wall are insufficient. Absent.

  The outer peripheral wall may have a length of 3% or more and 40% or less with respect to the inner diameter of the screw.

  In this case, since the outer peripheral wall is set to an appropriate length, the synthetic resin in the annular groove is shortened because the outer peripheral wall is too short, and the synthetic resin in the annular groove is deformed inwardly from the inner peripheral wall. There is no such thing.

  Further, since the outer peripheral wall is too long, the area in which the synthetic resin in the annular groove presses the inner peripheral wall is widened, and the pressing force is not insufficient.

  The cylindrical body may be formed with at least one dovetail groove having a cross-section in the circumferential direction of the outer peripheral surface.

  In this case, the pipe joint main body on the back side from the outer peripheral wall of the cylinder expands, so that a force is applied to peel off the joint surface between the inner peripheral surface of the pipe joint main body and the outer peripheral surface of the cylinder. Thus, the synthetic resin in the groove pushes the side wall on the opening end side of the groove, and the synthetic resin in the groove moves the side wall on the back end side of the groove using the side wall on the opening end side of the groove as a fulcrum. Press.

  Therefore, the fluid flow path is blocked by pressing from the synthetic resin in the groove to the side wall on the opening end side of the groove and from the synthetic resin in the groove to the side wall on the back end side of the groove. Therefore, the fluid can be prevented from leaking outside the pipe joint.

  Moreover, the said ditch | groove may be provided in the opening side rather than the middle of the both ends of the part embed | buried under the pipe joint main body among the said cylinders.

  In this case, since the groove is provided on the opening side away from the back end, the groove is affected by the expansion of the pipe joint body, which occurs when the groove is provided on the back end side. The amount of deformation of the inner synthetic resin increases, and the synthetic resin in the concave groove does not come off the side wall on the far end side of the concave groove.

  Further, the groove may have a depth of 2% or more with respect to the inner diameter of the screw.

  In this case, since the concave groove has an appropriate depth, if the concave groove is too shallow, the synthetic resin in the concave groove is shortened, and the synthetic resin in the concave groove comes off the side wall on the back end side. There is no such thing.

  The concave groove may have both bottom angles of 90 degrees or less.

  In this case, since the fitting between the synthetic resin in the groove and the groove is not released, the fluid flow path is pressed from the synthetic resin in the groove to the side wall on the opening end side of the groove. , And the synthetic resin in the groove can be blocked by pressing to the side wall on the back end side of the groove, and fluid can be prevented from leaking to the outside of the pipe joint.

  The pipe joint of the present invention has an effect that the fluid does not leak along the joint surface between the tube body and the pipe joint body when pressure is applied from the fluid flowing inside.

  Hereinafter, an embodiment of the present invention will be described with reference to FIG.

  FIG. 1 is a cross-sectional view showing a pipe joint according to an embodiment of the present invention.

  The pipe joint 1 according to the present embodiment includes a pipe joint main body 2 and a cylindrical body 3 that is embedded on one opening end side of the pipe joint main body 2.

  The pipe joint body 2 is not particularly limited as long as it is a synthetic resin. For example, a thermoplastic resin such as a vinyl chloride resin or a polyethylene resin, an unsaturated polyester resin, an epoxy resin, a dicyclopintadiene resin, or the like. A thermosetting resin etc. are mentioned. The pipe joint body 2 is not limited to a straight socket joint, but a reducer joint in which the pipe joint body 2 is partially constricted, an elbow joint in which the pipe joint is bent at 45 degrees, 90 degrees, etc., T-shape A shaped cheese joint or the like can be used.

  The said cylinder 3 is for connecting a metal pipe, The screw is provided in the connection part. The cylindrical body 3 includes an outer peripheral wall 33 and an inner peripheral wall 32 respectively extending from the outer peripheral edge and the inner peripheral edge of the rear end surface to the inner side, an annular groove 31 formed between the outer peripheral wall 33 and the inner peripheral wall 32, And a groove 34 having a dovetail cross section formed at least one in the circumferential direction of the outer peripheral surface. The cylindrical body 3 is not particularly limited as long as it is a metal. For example, a material having excellent corrosion resistance such as aluminum or bronze can be used.

  The screw may be a female screw 37 as shown in FIG. 1, and as shown in FIG. 6, in the tubular body 3 partially embedded in one opening end side of the pipe joint body 2, A male screw 38 may be formed on the portion protruding outward.

  The outer peripheral wall 33 is for preventing fluid leakage due to the adhesive force with the synthetic resin in the annular groove 31 when the pipe joint body 2 expands. The outer peripheral wall 33 may have a length in the range of 3% to 40% with respect to the inner diameter of the screw.

  When the outer peripheral wall 33 has a length of 3% or less of the inner diameter of the screw, the length of the synthetic resin in the annular groove 31 is shortened. Therefore, the synthetic resin in the annular groove 31 supports the tip of the outer peripheral wall 33 as a fulcrum. As a result, the synthetic resin in the annular groove 31 is detached from the inner peripheral wall 32 when trying to be deformed inward, so that the fluid flow path cannot be blocked.

  Further, when the outer peripheral wall 33 has a length of 40% or more of the inner diameter of the screw, the length of the synthetic resin in the annular groove 31 is increased. When an attempt is made to deform inward with fulcrum as a fulcrum, the area in which the synthetic resin in the annular groove 31 presses the inner peripheral wall 32 becomes wide. Therefore, the pressure to press becomes small, and it becomes impossible to block the fluid flow path.

  The inner peripheral wall 32 is for preventing fluid leakage due to the adhesive force with the synthetic resin in the annular groove 31 when the pipe joint body 2 expands. The inner peripheral wall 32 may be 50% or more and 100% or less of the length of the outer peripheral wall 33.

  When the inner peripheral wall 32 is less than 50% of the outer peripheral wall 33, when the synthetic resin in the annular groove 31 tries to deform inwardly with the tip of the outer peripheral wall 33 as a fulcrum, the synthetic resin in the annular groove 31 It will come off from the surrounding wall 32 and it will become impossible to interrupt | block the flow path of a fluid. At this time, the force with which the synthetic resin in the annular groove 31 presses the outer peripheral wall 33 also decreases, and the fluid flow path cannot be blocked.

  When the inner peripheral wall 32 is longer than the outer peripheral wall 33, the synthetic resin in the annular groove 31 is deformed inwardly with the tip of the outer peripheral wall 33 as a fulcrum when the synthetic resin in the annular groove 31 is deformed inward. The area for pressing is widened. Therefore, the pressure to press becomes small, and it becomes impossible to block the fluid flow path.

  The annular groove 31 is for blocking the fluid flow path by utilizing the adhesion between the synthetic resin filled therein and the inner peripheral wall 32 and the outer peripheral wall 33. The width of the annular groove 31 is preferably in the range of 20% or more and 70% or less of the thickness from the outer peripheral surface of the outer peripheral wall 33 to the inner peripheral surface of the inner peripheral wall 32. If it is 20% or less, the synthetic resin in the annular groove 31 becomes thin, and if it is 70% or more, the synthetic resin in the annular groove 31 becomes thick, so this synthetic resin presses the outer peripheral wall 33 and the inner peripheral wall 32. The pressing force is insufficient.

  The concave groove 34 has a close contact force between the filled synthetic resin and both side walls when a force is applied to peel off the joint surface between the inner peripheral surface of the pipe joint 1 and the outer peripheral surface of the cylindrical body 3. This is for blocking the fluid flow path.

  The depth of the concave groove 34 is preferably 2% or more of the inner diameter of the screw. When the depth of the concave groove 34 is 2% or less of the inner diameter of the screw, the synthetic resin in the concave groove 34 is shortened. Therefore, when a force for peeling off the joining surface is applied, This synthetic resin cannot press the side wall 36 on the back end side of the concave groove 34 with the side wall 35 on the opening end side of the concave groove 34 as a fulcrum. Further, when the synthetic resin in the concave groove 34 is to be deformed to the back end side with the side wall 35 on the opening end side of the concave groove 34 as a fulcrum, the synthetic resin in the concave groove 34 is It will come off from the side wall 36 on the side, and the pressing force on both side walls will be insufficient.

  The concave groove 34 is provided on the opening side from the middle of both ends of the portion embedded in the pipe joint body 2 of the cylindrical body 3, so that the concave groove 34 occurs when the concave groove 34 is provided on the far end side. Under the influence of the expansion of the joint body 2, the amount of deformation of the synthetic resin in the concave groove 34 increases, and the synthetic resin in the concave groove 34 does not come off the side wall 36 on the back end side of the concave groove 34.

  The concave groove 34 may have both bottom angles of 90 degrees or less, and the synthetic resin in the concave groove 34 and the concave groove 34 will not be disengaged. There is no shortage of pressing force from the resin to both side walls.

  In the pipe joint of the present invention, the groove 34 is not necessarily provided.

  Next, when the pipe joint 1 of the present invention is used, the action of blocking the fluid flow path at the joint surface between the pipe joint body 2 and the cylindrical body 3 will be briefly described with reference to the drawings.

  FIG. 2 is an enlarged cross-sectional view showing the annular groove 31 of the cylindrical body 3 in the pipe joint body 2. FIG. 3 is an enlarged cross-sectional view showing the concave groove 34 of the cylindrical body 3 in the pipe joint body 2.

  The pipe joint 1 is used by connecting a metal pipe to the cylindrical body 3 and connecting a synthetic resin pipe to the pipe joint main body 2. At this time, when fluid is supplied through the pipe joint 1, various sizes of pressure are applied to the inner peripheral surface of the pipe joint 1 from the fluid.

  At this time, the metal cylinder 3 constituting the pipe joint 1 and the synthetic resin pipe joint body 2 are greatly different in deformation amount due to the difference in material. That is, the metal cylinder 3 hardly deforms with respect to the pressure, whereas the synthetic resin pipe joint body 2 deforms so as to expand outward due to the pressure. Moreover, since one end of the pipe joint 1 is connected to the metal pipe, the expansion of the pipe joint body 2 occurs only on the back end side of the cylindrical body 3.

  Due to the expansion of the pipe joint body 2, a gap is formed in the joint surface between the pipe joint body 2 and the cylinder body 3 on the back end side of the tube body 3. Attempts to move outside the fitting through the weak joint surface.

  However, due to the expansion of the pipe joint body 2 to the outside, a force that presses outward from the synthetic resin in the annular groove 31 is generated at the tip of the outer peripheral wall 33 of the cylindrical body 3. Further, due to the expansion of the pipe joint body 2 to the outside, the synthetic resin in the annular groove 31 tries to deform inward with the tip of the outer peripheral wall 33 as a fulcrum, and acts so as to escape in the back end direction (FIG. 2 chain line state). reference). At this time, a force is generated in which the synthetic resin in the annular groove 31 presses the inner peripheral wall 32. For this reason, the synthetic resin in the annular groove 31 and the inner peripheral wall 32, and the synthetic resin in the annular groove 31 and the outer peripheral wall 33 are pressed tightly so that the fluid flow path can be blocked.

  Further, due to the outward expansion of the pipe joint main body 2, a force acts on the joining surface between the outer peripheral surface of the cylindrical body 3 and the inner peripheral surface of the pipe joint main body 2 in the peeling direction. With this force, the synthetic resin in the concave groove 34 presses the side wall 35 (see FIG. 3) on the opening end side of the concave groove 34, and the synthetic resin in the concave groove 34 moves on the opening end side of the concave groove 34. Using the side wall 35 as a fulcrum, a side wall 36 (see FIG. 3) on the back end side of the concave groove 34 is pressed. Due to these pressings, the synthetic resin in the groove 34 and the side wall 35 on the back end side of the groove 34, and the synthetic resin in the groove 34 and the side wall 35 on the opening end side of the groove 34 are in close contact with each other, Even if the fluid reaches the concave groove 34, the fluid flow path can be blocked.

  By providing the annular groove 31 and the concave groove 34 as described above, the pipe joint 1 in the present invention can block the fluid flow path and prevent the fluid from leaking to the outside of the pipe joint 1. be able to.

  Next, it shows about the water pressure test result done to the pipe joint 1 of this invention.

  FIG. 7 is a perspective view showing a pipe joint of the present invention attached to a hydraulic pressure testing machine, and FIG. 8 is a cross-sectional view showing the pipe joint at that time. The arrows in FIG. 8 indicate the pressure direction of water.

  In the water pressure test, a metal plug 4 is connected to one end of the pipe joint 1 and a water pressure tester is connected to the other end, and then the water pressure filled in the pipe joint 1 is measured by a water pressure tester. It was done by changing.

  The pipe joint 1 subjected to the water pressure test this time is the conventional pipe joint 10 shown in FIG. 9 (hereinafter referred to as a conventional example), the pipe joint 1 of the present invention shown in FIG. 1 (hereinafter referred to as Example 1), A pipe joint 1 (hereinafter referred to as Example 2) of a modified example of the present invention shown in FIG. 4 and a pipe joint 1 in which the concave groove 34 is not provided in the pipe joint 1 shown in FIG. 1 (hereinafter referred to as Example 3). It is.

  Here, Table 1 shows each dimension of the pipe joint 1 of Example 1, Example 2, Example 3 and the conventional example for which the experiment was conducted this time.

これらの管継手１に図７および図８に示す水圧試験を行い、以下のような結果が得られた。

These pipe joints 1 were subjected to the water pressure test shown in FIGS. 7 and 8, and the following results were obtained.

  In the pipe joint 10 of the conventional example, water leakage occurred when the water pressure was 50 MPa. In the pipe joint 1 of Example 3, water leakage occurred when the water pressure was 150 MPa. Moreover, in the pipe joint 1 of Example 1 and Example 2, water leakage did not occur until the water pressure was set to 300 MPa and 250 MPa, respectively, and when the water pressure was exceeded, the limit water pressure of the pipe joint body 2 was reached. The pipe joint body 2 was broken.

  As described above, when the hydraulic pressure test results of Example 3 and the conventional example were compared, the critical water pressure of the water leakage of the pipe joint 1 of Example 3 was improved to three times that of the pipe joint 10 of the conventional example. Moreover, when the hydraulic pressure test result of Example 1 and Example 3 was compared, the critical water pressure of the pipe joint 1 was able to be improved 2 times by forming the ditch | groove 34. FIG. Moreover, when the hydraulic pressure test result of Example 1 and Example 2 is compared, the critical water pressure of the pipe joint 1 can be improved by changing the length of the inner peripheral wall 32 with respect to the outer peripheral wall 33, and the outer peripheral wall When the length of 33 and the inner peripheral wall 32 were made equal, the best water pressure test result was obtained.

It is sectional drawing which shows the pipe joint in this invention. It is an expanded sectional view which shows the A section of the pipe joint of FIG. It is an expanded sectional view which shows the B section of the pipe joint of FIG. It is sectional drawing which shows the modification of the pipe joint in this invention. It is an expanded sectional view which shows the C section of the pipe joint of FIG. It is sectional drawing which shows other embodiment of the pipe joint in this invention. It is a perspective view explaining the water pressure test of the pipe joint of the present invention. It is sectional drawing explaining the water pressure test of the pipe joint of this invention. It is sectional drawing which shows the conventional pipe joint. It is an expanded sectional view which shows the D section of the pipe joint of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pipe joint 2 Pipe joint main body 3 Cylindrical body 31 Annular groove 32 Inner peripheral wall 33 Outer peripheral wall 34 Concave groove 35 Side wall 36 on the open end side Side wall 37 on the rear end side Female screw 38 Male screw 4 Plug body 5

Claims (7)

A synthetic resin pipe fitting body;
A metal cylinder at least partially embedded in the open end of the pipe joint body and provided with a screw; and
In the pipe joint provided with the outer peripheral wall and the inner peripheral wall respectively extending from the outer peripheral edge and the inner peripheral edge of the rear end surface of the cylindrical body to the rear side
The length of the inner peripheral wall is 50% or more and 100% or less of the length of the outer peripheral wall.   The width of the annular groove formed between the outer peripheral wall and the inner peripheral wall is 20% or more and 70% or less of the thickness from the outer peripheral surface of the outer peripheral wall to the inner peripheral surface of the inner peripheral wall. The pipe joint according to claim 1.   The pipe joint according to claim 1 or 2, wherein the length of the outer peripheral wall is 3% or more and 40% or less with respect to the inner diameter of the screw.   The pipe joint according to any one of claims 1 to 3, wherein the cylindrical body is formed with at least one groove having a cross-sectional dovetail shape in the circumferential direction of the outer peripheral surface.   5. The pipe joint according to claim 4, wherein the concave groove is provided on the opening side from the middle of both ends of a portion of the cylindrical body embedded in the pipe joint main body.   The pipe joint according to claim 4 or 5, wherein the depth of the concave groove is 2% or more with respect to the inner diameter of the screw.   The pipe joint according to any one of claims 4 to 6, wherein each of the concave grooves has a bottom angle of 90 degrees or less.

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