Male side pipe fitting

Abstract

To produce a resin-made male side pipe fitting allowing for the attachment of two seal members without parting lines that extend across the bottom of the seal groove or extend vertically along the side walls of the seal groove.SOLUTION: A male side pipe fitting (101) includes a cylindrical first body (1) composed of a resin material, and a second body (2) integrally molded with a cylinder (3) of the first body (1) and composed of a resin material. The first body (1) includes, on its outer surface, a first annular projection (4) and a second annular projection (5) that form the side walls of a seal groove for the attachment of annular seal members. The first annular projection (4) and the second annular projection (5) are both separate units from the cylinder (3) and are fixed on the outer surface of the cylinder (3).SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a male pipe joint made of resin.

Background Art

[0002] Patent Document 1 describes a pipe joint for connecting pipes. This pipe joint is used, for one application, to connect refrigerant pipes that form a refrigerant circuit of a vehicle air conditioner.

[0003] The above pipe joint is composed of a male member and a female member. The male member is provided with two holding grooves for holding an O-ring. These two holding grooves are grooves with different widths, and the holding groove on the flange side is a groove with a narrower width. O-rings of the same material, shape, and size are mounted in the two holding grooves. With these configurations, the O-ring on the flange side of the male member protrudes outward, thereby improving the sealing performance of the pipe joint.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Conventionally, automotive air conditioner pipes (refrigerant pipes) and their pipe joints (pipe joints as described in Patent Document 1) are made of aluminum (metal). On the other hand, in recent years, in order to improve the fuel efficiency of gasoline vehicles and extend the driving range of electric vehicles, it has been considered to reduce the weight of automobiles by replacing metal parts such as air conditioner pipes and their pipe joints with resin parts.

[0006] Here, if we attempt to integrally mold the male component of a pipe fitting, such as the one described in Patent Document 1, which is fitted with two O-rings, by injection molding, the following problems arise.

[0007] To allow the mold to be removed from the molded male component, the injection molding mold must be a split mold (a mold that is like a cylinder split in two along its axial direction). With such a split mold, it is impossible to avoid the formation of a parting line in the O-ring retaining groove (seal groove). When a parting line is formed, there is a possibility that gas leakage will occur from the pipe joint along that parting line. This parting line refers to the parting line that forms at the bottom or on the side wall of the retaining groove. The parting line that forms at the bottom of the retaining groove extends across the bottom of the retaining groove. The parting line that forms on the side wall of the retaining groove extends vertically along the side wall of the retaining groove. When such parting lines are formed, it is difficult to reduce the surface roughness of the bottom or side wall of the retaining groove.

[0008] The object of the present invention is to manufacture a resin male pipe fitting that can accommodate two sealing members, without parting lines that extend across the bottom of the seal groove or vertically along the side wall of the seal groove. [Means for solving the problem]

[0009] The male pipe fitting disclosed herein comprises a cylindrical first main body made of a resin material and a second main body made of a resin material integrally molded with the cylindrical part of the first main body. The first main body has a first annular projection and a second annular projection on its outer circumferential surface that form the side wall of a seal groove into which an annular sealing member is fitted, and both the first annular projection and the second annular projection are separate from the cylindrical part and fixed to the outer circumferential surface of the cylindrical part. [Effects of the Invention]

[0010] With the male pipe fitting configured as described above, it is possible to manufacture a resin male pipe fitting that can accommodate two sealing members, without parting lines that extend across the bottom of the seal groove or vertically along the side wall of the seal groove. [Brief explanation of the drawing]

[0011] [Figure 1] This is a side cross-sectional view of a male pipe fitting according to one embodiment of the present invention, in which piping is connected. [Figure 2] Figure 1 is a front view of the male side pipe fitting. [Figure 3] This is a side cross-sectional view of the integrally molded cylindrical portion and the second main body portion. [Modes for carrying out the invention]

[0012] Embodiments for carrying out the present invention will be described with reference to the drawings. The male pipe fitting of the present invention is not limited to male pipe fittings used in air conditioning piping (refrigerant pipes) for automobiles, but is a male pipe fitting that can be used for connecting various types of piping.

[0013] As shown in Figure 1, the male pipe fitting 101 comprises a first main body 1 and a second main body 2. This male pipe fitting 101 is used, for example, as a male pipe fitting among pipe fittings for connecting pipes in automotive air conditioning piping (refrigerant pipes). In this application, the female pipe fitting corresponding to the male pipe fitting 101 is not shown.

[0014] The first main body 1 is the part that is inserted into the female side pipe fitting (not shown). The first main body 1 has a cylindrical shape. The first main body 1 is composed of a cylindrical part 3, a first annular projection 4, and a second annular projection 5. The cylindrical part 3, the first annular projection 4, and the second annular projection 5 are all made of resin material. The cylindrical hole 3a of the cylindrical part 3 is a hole that serves as a flow path for the refrigerant (fluid).

[0015] As shown in Figures 1 and 3, a stepped portion 8 is formed at the boundary between the cylindrical portion 3 and the second main body portion 2. The stepped portion 8 is an annular stepped portion that protrudes radially outward from the cylindrical portion 3.

[0016] As shown in Figure 1, the first annular projection 4 is provided on the outer circumferential surface of one axial end of the cylindrical portion 3. The axial end of the cylindrical portion 3 is the end of the cylindrical portion 3 that is inserted into the female pipe fitting. In other words, the axial end of the cylindrical portion 3 is the end of the cylindrical portion 3 opposite to the second main body portion 2. The first annular projection 4 is separate from the cylindrical portion 3 and is fixed to the outer circumferential surface of the cylindrical portion 3. The first annular projection 4 is a ring-shaped component made of resin. Note that the first annular projection 4 may be provided at a position slightly away from the end of the cylindrical portion 3. That is, the position of the first annular projection 4 is not limited to the end of the cylindrical portion 3.

[0017] In contrast, the second annular projection 5 is provided on the outer circumferential surface of the cylindrical portion 3 at an intermediate point in the axial direction. The second annular projection 5 is provided at approximately the center in the axial direction between the first annular projection 4 and the stepped portion 8. Like the first annular projection 4, the second annular projection 5 is separate from the cylindrical portion 3 and is fixed to the outer circumferential surface of the cylindrical portion 3. The second annular projection 5 is a ring-shaped component made of resin.

[0018] A first seal groove S1 is formed by the first annular projection 4, the second annular projection 5, and the outer circumferential surface of the cylindrical portion 3 between the first annular projection 4 and the second annular projection 5. An annular sealing member (not shown) is fitted into this first seal groove S1. The annular sealing member is, for example, an O-ring. The material of the O-ring is rubber or resin. The first annular projection 4 and the second annular projection 5 each form the side walls of the first seal groove S1. The outer circumferential surface of the cylindrical portion 3 between the first annular projection 4 and the second annular projection 5 forms the bottom surface of the first seal groove S1.

[0019] Further, a second annular convex portion 5, a step portion 8, and the outer peripheral surface of the cylindrical portion 3 between the second annular convex portion 5 and the step portion 8 form a second seal groove S2. An annular seal member (not shown) is mounted in this second seal groove S2. The annular seal member is, for example, an O-ring. The material of the O-ring is rubber or resin. The second annular convex portion 5 and the step portion 8 respectively form the side walls of the second seal groove S2. The outer peripheral surface of the cylindrical portion 3 between the second annular convex portion 5 and the step portion 8 forms the bottom surface of the second seal groove S2.

[0020] In order to ensure sufficient sealing performance, the heights of the first annular convex portion 4, the second annular convex portion 5, and the step portion 8 are all made equal. The height of the first annular convex portion 4 is the distance in the radial direction of the cylindrical portion 3 between the outer peripheral surface of the cylindrical portion 3 and the outer peripheral surface of the first annular convex portion 4 (the same applies to the second annular convex portion 5). The height of the step portion 8 is the height of the step protruding outward in the radial direction of the cylindrical portion 3 in the step portion 8. Note that the heights of the first annular convex portion 4, the second annular convex portion 5, and the step portion 8 do not necessarily have to be all equal.

[0021] In this way, seal grooves S1 and S2 for mounting two O-rings (annular seal members) are formed in the first main body portion 1. Note that the step portion 8 may be absent. When the step portion 8 is absent and the length of the cylindrical portion 3 is the same as that shown in FIG. 1, the width of the second seal groove S2 will be too wide. Therefore, when the step portion 8 is absent, the cylindrical portion 3 is made shorter than that shown in FIG. 1 accordingly.

[0022] The second main body portion 2 is a so-called flange portion for firmly connecting the male-side pipe joint 101 and the female-side pipe joint so that they do not separate due to the pressure of the refrigerant or the like. The second main body portion 2 is integrally formed with the cylindrical portion 3 of the first main body portion 1. The second main body portion 2 is made of a resin material. The second main body portion 2 is composed of a main body portion 6 in which a hole 6a serving as a refrigerant flow path is formed, and a fastening portion 7 extending from the main body portion 6. As shown in FIG. 2, the fastening portion 7 extends from the main body portion 6 outward in the radial direction of the hole 6a.

[0023] On the surface of the main body portion 6 opposite to the stepped portion 8, a cylindrical receiving port 9 into which a resin pipe 50 is inserted and fixed is provided. The pipe 50 is inserted outside the receiving port 9.

[0024] A hole 7a into which a cylindrical collar 10 is fitted is formed in the fastening portion 7. A bolt (not shown) is inserted into the collar 10 fitted in the hole 7a. The female pipe joint has the same structure, and the female pipe joint includes a flange portion having a hole into which a bolt is inserted. The male pipe joint 101 and the female pipe joint are firmly connected and fixed by the inserted bolt and a nut (not shown). Note that the connecting means between the male pipe joint 101 and the female pipe joint is not limited to bolts and nuts. Also, depending on the position where the male pipe joint 101 is used, bolts and nuts may not be required for connecting the male pipe joint 101 and the female pipe joint. Therefore, in the male pipe joint 101, the portion extending from the main body portion 6 like the fastening portion 7 may not be provided.

[0025] A manufacturing method of the male pipe joint 101 will be described.

[0026] FIG. 3 is a view showing the integrally formed cylindrical portion 3 and the second main body portion 2. The cylindrical portion 3 of the first main body portion 1 and the second main body portion 2 are integrally formed by injection molding. The second main body portion 2 exists at one end of the cylindrical portion 3, but there is nothing protruding radially outward of the cylindrical portion 3 at the other end of the cylindrical portion 3. Therefore, as a mold for injection molding the cylindrical portion 3, a single cylindrical mold without a split surface can be used instead of a mold (split mold) that divides a cylinder into two along its axial direction. This is because the mold can be removed from the molded product without using a pair of split molds.

[0027] When the above cylindrical mold is used, no parting lines extending in the axial direction of the cylindrical portion 3 are formed on the outer circumferential surface of the cylindrical portion 3 that forms the bottom surface of the first seal groove S1 and the bottom surface of the second seal groove S2. In other words, no parting lines extending across the bottoms of the first seal groove S1 and the second seal groove S2 are formed. Therefore, a resin cylindrical portion 3 without parting lines extending across the bottoms of each seal groove S1 and S2 can be obtained. As a result, there is no concern that gas leakage will occur from the pipe joint (between the male pipe joint 101 and the female pipe joint) via the parting line. In addition, the surface roughness of the bottom surfaces of each seal groove S1 and S2 can be reduced, resulting in a male pipe joint 101 with excellent sealing performance.

[0028] Next, the first annular projection 4 and the second annular projection 5, which were prepared separately, are fixed to the outer surface of the cylindrical portion 3 (see Figure 1). The first annular projection 4 and the second annular projection 5 are ring-shaped parts made of resin. Since the first annular projection 4 and the second annular projection 5 are also made of resin material, they are also manufactured by injection molding using a mold.

[0029] Here, the material of the cylindrical portion 3, including the second main body portion 2, is a resin material that absorbs laser light. In contrast, the materials of the first annular protrusion 4 and the second annular protrusion 5 are both resin materials that transmit laser light. Note that the material of the cylindrical portion 3, including the second main body portion 2, may be a resin material other than a resin material that absorbs laser light. Also, the materials of the first annular protrusion 4 and the second annular protrusion 5 may be a resin material other than a resin material that transmits laser light.

[0030] The second annular projection 5 is fitted onto the outer surface of the cylindrical portion 3, and the second annular projection 5 is brought into close contact with the outer surface of the cylindrical portion 3. Then, as shown by the arrow in Figure 1, laser light is irradiated from the radially outer side of the cylindrical portion 3 toward the second annular projection 5, over the entire circumference of the second annular projection 5 (cylindrical portion 3). Note that the laser light does not have to be irradiated over the entire circumference. When the laser light is irradiated, the laser light passes through the second annular projection 5 and is absorbed by the outer surface of the cylindrical portion 3. The part of the outer surface of the cylindrical portion 3 that is irradiated with the laser light generates heat and melts. This heat is transferred to the second annular projection 5 which is in close contact with the heated part of the outer surface of the cylindrical portion 3, and the part of the second annular projection 5 that is in contact with it also melts. The molten materials then mix together. When the laser light irradiation is stopped, the temperature of the molten material decreases and the material solidifies. In this way, the second annular projection 5 is welded and fixed to the outer surface of the cylindrical portion 3 by laser light.

[0031] The welding and fixing of the first annular projection 4 to the outer circumferential surface of the cylindrical portion 3 is the same as in the case of the second annular projection 5. The first annular projection 4 is welded and fixed to the outer circumferential surface of the end of the cylindrical portion 3 using laser light. This manufactures the male pipe joint 101.

[0032] The male pipe fitting 101 and the pipe 50 are fixed together, for example, as follows. The material of the pipe 50 is a resin material that is transparent to laser light. However, the material of the pipe 50 may be a resin material other than a resin material that is transparent to laser light.

[0033] The end of the pipe 50 is pushed into the receiving opening 9 of the second main body 2, and the pipe 50 is brought into close contact with the outer surface of the receiving opening 9. Then, as shown by the arrow in Figure 1, a laser beam is shone from the outside in the radial direction of the pipe 50 toward the pipe 50, along the entire circumference of the pipe 50. As a result, the male pipe fitting 101 and the pipe 50 are welded and fixed together by the laser beam.

[0034] The male pipe joint 101 according to one embodiment of the present invention has been described above. The following technical features of the male pipe joint have been disclosed as described above.

[0035] (1) The male side pipe fitting 101 comprises a cylindrical first main body portion 1 made of resin material and a second main body portion 2 made of resin material which is integrally molded with the cylindrical portion 3 of the first main body portion 1. The first main body portion 1 has a first annular projection 4 and a second annular projection 5 on its outer surface which form the side wall of a seal groove into which an annular sealing member (for example, an O-ring) is fitted. Both the first annular projection 4 and the second annular projection 5 are separate from the cylindrical portion 3 and are fixed to the outer surface of the cylindrical portion 3.

[0036] With this configuration, since the first annular projection 4 and the second annular projection 5 are both separate parts, when manufacturing the cylindrical portion 3 by injection molding, a cylindrical mold without a dividing surface can be used as the mold for injection molding the cylindrical portion 3, rather than a mold that is like a cylinder split in two along its axial direction (split mold). When a cylindrical mold is used, no parting lines extending in the axial direction of the cylindrical portion 3 can be formed on the outer circumferential surface of the cylindrical portion 3 that forms the bottom surface of the first seal groove S1 and the bottom surface of the second seal groove S2. In other words, no parting lines extending across the bottom of the first seal groove S1 and the second seal groove S2 can be formed. Furthermore, when manufacturing the first annular projection 4 and the second annular projection 5, a cylindrical mold without a dividing surface can be used, rather than a mold that is like a cylinder split in two along its axial direction (split mold). Therefore, no parting lines extending vertically (in the radial direction of the cylindrical portion 3) can be formed on the side walls of the first annular projection 4 and the second annular projection 5. Therefore, it is possible to manufacture a resin male pipe fitting 101 that can accommodate two sealing members, without parting lines that extend across the bottom of the seal groove or vertically along the side wall of the seal groove.

[0037] Furthermore, by integrally molding the cylindrical portion 3 of the first main body 1 and the second main body 2, the number of molds can be reduced compared to when the cylindrical portion 3 and the second main body 2 are separate parts, thereby lowering the manufacturing cost of the male pipe joint.

[0038] (2) In the male pipe joint 101 described in (1) above, the first annular projection 4 and the second annular projection 5 may both be welded and fixed to the outer surface of the cylindrical portion 3 by laser light.

[0039] This configuration allows for a firm fixation between the first annular projection 4 and the cylindrical portion 3, and between the second annular projection 5 and the cylindrical portion 3.

[0040] (3) In the male pipe joint 101 described in (2) above, the cylindrical portion 3 and the second main body portion 2 are made of a resin material that absorbs laser light, and the first annular projection 4 and the second annular projection 5 may both be made of a resin material that transmits laser light.

[0041] This configuration allows for easy welding using laser light, i.e., laser welding.

[0042] (4) In the male pipe joint 101 described in any of (1) to (3) above, an annular stepped portion 8 that protrudes radially outward from the cylindrical portion 3 is formed at the boundary between the cylindrical portion 3 and the second main body portion 2, and in addition to the first annular protrusion 4 and the second annular protrusion 5, the stepped portion 8 may form the side wall of the seal groove.

[0043] This configuration allows for increased strength at the boundary between the cylindrical portion 3 and the second main body portion 2, and also facilitates the formation of a sealing groove.

[0044] The present invention is not limited to the embodiments described above, and it is possible to combine elements of the embodiments as appropriate or to make various modifications to the embodiments without departing from the spirit of the invention.

[0045] For example, the above embodiment can be modified as follows:

[0046] The method of fixing the first annular projection 4 and the second annular projection 5 to the cylindrical portion 3 is not limited to laser welding. The first annular projection 4 and the second annular projection 5 may be fixed to the outer circumferential surface of the cylindrical portion 3 by fitting. Alternatively, one of the first annular projection 4 and the second annular projection 5 may be fixed to the cylindrical portion 3 by laser welding, and the other may be fixed to the cylindrical portion 3 by fitting.

[0047] Furthermore, other fixing methods besides those mentioned above include spin welding, ultrasonic welding, and vibration welding. That is, the fixing of the first annular projection 4 to the cylindrical portion 3, or the fixing of the second annular projection 5 to the cylindrical portion 3, may be carried out by methods such as spin welding, ultrasonic welding, or vibration welding.

[0048] In the second main body section 2, the color 10 is optional. [Explanation of Symbols]

[0049] 1: First main body 2: Second main body 3: Cylinder part 4: First ring-shaped protrusion 5: Second ring-shaped protrusion 8: Stepped section 101: Male side pipe fitting S1: First seal groove (seal groove) S2: Second seal groove (seal groove)

Claims

1. A cylindrical first main body made of resin material, A second main body made of a resin material integrally molded with the cylindrical portion of the first main body, Equipped with, The first main body has a first annular projection and a second annular projection on its outer surface that form the side wall of a seal groove into which an annular sealing member is fitted. The first annular projection and the second annular projection are both separate from the cylindrical portion and fixed to the outer circumferential surface of the cylindrical portion. Male side pipe fitting.

2. In the male side pipe joint according to claim 1, Both the first annular projection and the second annular projection are welded and fixed to the outer surface of the cylindrical portion by laser light. Male side pipe fitting.

3. In the male side pipe joint according to claim 2, The cylindrical portion and the second main body portion are formed of a resin material that absorbs laser light. Both the first annular protrusion and the second annular protrusion are formed of a resin material that is transparent to laser light. Male side pipe fitting.

4. In the male side pipe fitting according to any one of claims 1 to 3, An annular step portion is formed at the boundary between the cylindrical portion and the second main body portion, which protrudes radially outward from the cylindrical portion. In addition to the first annular projection and the second annular projection, the stepped portion forms the side wall of the seal groove. Male side pipe fitting.

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