JP2018086771A - Production method for resin-made pipe joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method for a resin-made pipe joint capable of preventing liquid leakage that may be caused by a production process.SOLUTION: A production method for a resin-made pipe joint equipped with a joint body comprises a process of preparing a mold 50 having a cavity 51 for molding a flow channel wall of the joint body and a gate 53 communicating with the cavity, and a process of pouring molten resin into the cavity via the gate. The mold has an outer mold 55 including an inner face 56 facing the cavity, and a recessed part 57 formed at an inner surface side of the outer mold to open toward the cavity. The gate having an opening smaller than a bottom 58 of the recessed part is provided on the bottom of the recessed part to communicate with the cavity. A depth d of the recessed part is set to be 5% or more and 25% or less with respect to a numeric value of a flow channel wall thickness of the joint body defined by the cavity.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a method for manufacturing a resin pipe joint.

  2. Description of the Related Art Conventionally, resin pipe joints that can be used in manufacturing apparatuses in technical fields such as semiconductor manufacturing, medical / pharmaceutical manufacturing, food processing, and chemical industry are known (see, for example, Patent Document 1). This type of resin pipe joint is used to connect a tube for circulating a fluid such as ultrapure water or a chemical solution to another tube or a fluid device, and can be joined to one longitudinal end of the tube. It is configured.

  The resin pipe joint includes a joint body, an inner ring, and a union nut for joining with one end in the longitudinal direction of the tube, and one end in the longitudinal direction of the tube into which the inner ring and the tube are press-fitted. Are inserted into the joint body, and one end in the longitudinal direction of the tube can be held by the union nut so as not to be pulled out from the joint body.

JP-A-10-54489

  When manufacturing a conventional resin pipe joint, more specifically, a joint body, since the joint body is made of resin, a mold 80 corresponding to the joint body as shown in FIG. 7 is prepared. The mold 80 includes a cavity 81 for molding the flow path wall of the joint body, a runner 82 for guiding the molten resin to the cavity 81, and a gate 83 for communicating the cavity 81 and the runner 82. It is what you have.

  Next, molten resin supplied by the resin supply device is injected from the runner 82 into the cavity 81 through the gate 83. And the molten resin with which the cavity 81 was filled is hardened by cooling, and a molded article is obtained. In the molded product, surplus resin 85 (see FIG. 8) is generated along the runner 82 in the vicinity of the gate 83 where the molten resin was injected, so gate cutting is performed using a gate cutting jig. The joint body 86 is completed.

  In the molded product, the cured resin has a layered shape that is in close contact with the orientation. Therefore, when gate cutting is performed on the molded product to remove excess resin 85, the resin layer is located on the outer surface side (gate) in the vicinity of the location where the gate 83 is located (where the gate 83 is installed). 83), the resin layer may be collapsed such that adjacent resin layers are peeled apart.

  Then, as shown in FIG. 8, a crack 88 occurs from the outer surface side (the side where the gate 83 is installed) between the peeled layers of the adjacent resin. A through-hole 89 that penetrates the flow path wall 90 may be formed so as to connect the two. Therefore, there is a concern that a resin pipe joint (joint body) that can cause a problem that the through-hole 89 leaks the fluid flowing through the fluid flow passage 91 to the inside of the joint body 86 to the outside of the joint body 86 is manufactured. there were.

  This invention is made | formed in view of such a situation, and it aims at provision of the manufacturing method of the resin pipe joints which can prevent the fluid leakage which may be caused due to a manufacturing process.

The present invention
In the method of manufacturing a resin pipe joint provided with a joint body having a fluid flow path for circulating a fluid,
Preparing a cavity for molding the flow path wall of the joint body, and a mold having a gate communicating with the cavity;
Injecting molten resin into the cavity through the gate,
The mold is
An outer mold including an inner surface facing the cavity, and a recess formed on the inner surface side of the outer mold so as to open to the cavity;
The gate has an opening smaller than the bottom of the recess, and is provided at the bottom of the recess so as to communicate with the cavity via the internal space of the recess;
The depth of the recess is set to 5% or more and 25% or less with respect to the numerical value of the wall thickness of the flow path wall of the joint body defined by the cavity.

  According to this configuration, the molten resin can be injected into the cavity from the internal space of the concave portion while being injected into the internal space of the concave portion through the gate. Therefore, a molded product that forms the joint body can be obtained by filling the interior space of the cavity and the recess with the molten resin and curing the filled molten resin by cooling. In this molded product, a protrusion (pedestal) can be provided in the vicinity of the gate, which was the molten resin injection portion, due to the presence of the recess.

  Therefore, when a gate cut jig is used for the molded product for gate cutting, the resin layer (skin layer located at the outermost layer) in the molded product is pulled to the outer surface side. Thus, even when the adjacent resin layer in the molded product is peeled off so that a crack occurs between the two from the outer surface side, the gate cut is performed at the place where the pedestal is located in the molded product. Since it can be performed, the crack can be prevented from reaching the flow path wall from the vicinity of the gate installation location.

  That is, even when the crack is generated from the outer surface side of the molded product due to the gate cut, a relatively large thickness can be ensured due to the presence of the pedestal at the crack occurrence location in the molded product. Can be generally accommodated in the pedestal. Therefore, it is possible to prevent a through hole that connects the outside and the inside (fluid flow path) of the joint body from being formed in the flow path wall of the joint body due to the crack. Therefore, it is possible to prevent the fluid leakage caused by the through hole in the joint body.

  Moreover, the pedestal has a height corresponding to this depth by setting the dimension range of the depth of the recess. Therefore, if the height of the pedestal deviates from an appropriate dimension range and is lower than the dimension range, the gate cut defect may be caused, and if the height of the pedestal is higher than the dimension range, In addition, sink marks are generated on the inner surface of the flow path wall located inside the pedestal, and there is a possibility that smooth flow of fluid in the fluid flow path may be hindered by the sink marks, but the occurrence of these problems can be prevented.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the resin pipe joint which can prevent the fluid leakage which may be caused by a manufacturing process can be provided.

It is a side view of the resin pipe joint which can be manufactured using the manufacturing method of the resin pipe joint which concerns on this embodiment. It is side surface sectional drawing of the resin pipe joint of FIG. It is the schematic of the preparation process in the manufacturing method for manufacturing the resin pipe joint of FIG. It is the schematic of the injection | pouring process in the manufacturing method for manufacturing the resin pipe joint of FIG. It is a partially expanded sectional view which shows the state in the middle of manufacture of the coupling main body in the resin pipe coupling of FIG. It is a partially expanded sectional view which shows the completion state of the coupling main body of FIG. It is a partially expanded sectional view which shows the state in the middle of manufacture of the coupling main body in the conventional resin pipe coupling. It is a partially expanded sectional view which shows the completion state of the coupling main body of FIG.

  An embodiment of the present invention will be described with reference to the drawings.

  First, a schematic configuration of the resin pipe joint 1 that can be manufactured using the method for manufacturing a resin pipe joint according to the present embodiment will be described.

  As shown in FIGS. 1 and 2, the resin pipe joint 1 includes a resin joint body 2, a resin inner ring 3, and a resin union nut 4. In the present embodiment, the resin pipe joint 1 is of an elbow type and is configured to be able to be joined to each of the two tubes 5 and 6. The tubes 5 and 6 are made of a resin, for example, a fluororesin such as PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer).

  The joint body 2 has a fluid flow path 8 for circulating fluid. The joint body 2 communicates with one end portion in the longitudinal direction of the tube 5 at the first end portion 11 including one end portion in the flow direction of the fluid flow path 8 and the second end including the other end portion in the flow direction of the fluid flow path 8. The inner ring 3 and the union nut 4 are used to connect to the tubes 5 and 6 so that the portion 12 communicates with one end in the longitudinal direction of the tube 6.

  Specifically, the joint body 2 is made of PFA, PVDF (polyvinylidene fluoride), ETFE (tetrafluoroethylene / ethylene copolymer), FEP (tetrafluoroethylene / hexafluoropropylene copolymer) or PTFE (polytetrafluoroethylene). ) And other fluororesins. The joint main body 2 has a cylindrical shape having an L shape, and includes a connecting cylindrical portion 13 interposed between the first end portion 11 and the second end portion 12. The connecting cylinder portion 13 includes a bent portion 14 that bends at a substantially right angle.

  The connection structure of the first end portion 11 of the joint body 2 to the tube 5 and the connection structure of the second end portion 12 of the joint body 2 to the tube 6 are substantially the same. The connection structure of the 1st end part 11 of the main body 2 is demonstrated, and description of the connection structure of the 2nd end part 12 of the coupling main body 2 with respect to the tube 6 is abbreviate | omitted.

  The first end portion 11 of the joint body 2 has an inner diameter that is substantially the same as the inner diameter of each of the connecting cylinder portion 13 and the inner ring 3. The first end portion 11 includes a receiving portion 16 and a seal tube portion 17. The receiving portion 16 is formed in a cylindrical shape so that one end in the longitudinal direction of the tube 5 into which the inner ring 3 is press-fitted can be inserted. A male screw portion 18 is provided on the outer peripheral portion of the receiving portion 16.

  The seal cylinder portion 17 is disposed at a predetermined interval radially inward from the receiving portion 16 and is disposed coaxially with the receiving portion 16. The seal tube portion 17 is provided such that the axially outer end portion is positioned more inward in the axial direction (on the connecting tube portion 13 side) than the axially outer end portion of the receiving port portion 16. An inclined surface whose inner diameter gradually increases outward in the axial direction is provided at the axially outer end of the seal cylinder portion 17.

  A seal groove 19 is provided between the outer peripheral surface of the seal cylinder portion 17 and the inner peripheral surface of the receiving portion 16 facing the seal cylindrical portion 17. The seal groove 19 is formed in an annular shape so as to open outward in the axial direction of the seal tube portion 17. When the inner ring 3 is inserted into the receiving portion 16, a seal protrusion 23 described later on the inner ring 3 is provided. It is configured so that it can be press-fitted from the opening.

  The connecting cylinder portion 13 of the joint body 2 has a flow path wall 20 for forming the fluid flow path 8. The flow path wall 20 has a cylindrical shape having an inner diameter corresponding to the fluid flow path 8. The flow path wall 20 has a substantially constant thickness (radial width) t in the flow direction of the fluid flow path 8. A protruding portion (pedestal) 21 that protrudes radially outward from the outer surface of the flow path wall 20 is provided in the middle portion of the flow path wall 20, more specifically, the bent portion 14.

  The inner ring 3 is manufactured using a fluororesin such as PFA, PVDF, ETFE, FEP, or PTFE. The inner ring 3 has a cylindrical shape that can be inserted into the receiving port 16 and can be press-fitted into one end in the longitudinal direction of the tube 5 in order to communicate the joint body 2 (seal tube portion 17) with the tube 5. The inner ring 3 has an outer diameter that is larger than the inner diameter of the tube 5 and an inner diameter that is substantially the same.

  The inner ring 3 is configured such that one end in the axial direction can be press-fitted into one end in the longitudinal direction of the tube 5. An annular bulging portion 22 bulging outward in the radial direction is provided on one axial end portion side of the inner ring 3. When the inner ring 3 is press-fitted into the tube 5, the bulging portion 22 is configured to expand a part of one end portion in the longitudinal direction of the tube 5 as compared with the other portion.

  The inner ring 3 includes a cylindrical seal protrusion 23 that protrudes in the other axial direction on the other axial end side. The seal projection 23 has an outer diameter substantially the same as the outer diameter of the other portion at one end in the longitudinal direction of the tube 5 in a state where the inner ring 3 is press-fitted. The inner ring 3 further includes an inclined protrusion 24 whose outer diameter gradually decreases toward the other axial direction on the inner peripheral side of the seal protrusion 23.

  The union nut 4 is manufactured using a fluororesin such as PFA, PVDF, ETFE, FEP, or PTFE. The union nut 4 has a cylindrical shape that can be fitted to the receiving portion 16 of the joint body 2 and can be loosely fitted to the tube 5. The union nut 4 is configured to be attachable to the joint body 2 (receiving port 16) from the outer peripheral side, and can be tightened to the receiving port 16 when being mounted.

  The union nut 4 includes an annular pressing portion 26 that extends inward in the radial direction and protrudes on one axial end portion side. The union nut 4 further includes an annular threaded portion 27 that is connected to the radially outer end of the pressing portion 26 and can surround the receiving portion 16 on the other axial end side. A female screw portion 28 that can be screwed with the male screw portion 18 of the receiving portion 16 is provided on the inner peripheral portion of the screwing portion 27.

  With such a configuration, the other end side in the axial direction of the inner ring 3 is inserted into the receiving portion 16 of the joint body 2 together with one end in the longitudinal direction of the tube 5 into which the one end side in the axial direction of the inner ring 3 is press-fitted. The union nut 4 loosely fitted in the tube 5 in the inserted state is screwed axially inward with respect to the joint body 2 (receiving part 16), so that the tube 5 is fitted to the first end 11 of the joint body 2. Can be connected.

  At that time, the pressing portion 26 of the union nut 4 presses the expanded diameter portion 29 of the tube 5 that is expanded radially outward by the expanded portion 22 toward the expanded portion 22. Then, the seal projection 23 is press-fitted into the seal groove 19, and the inner peripheral surface of the seal projection 23 is in pressure contact with the outer peripheral surface of the seal tube portion 17. Further, the outer peripheral surface of the inclined protrusion 24 is in pressure contact with the inclined surface of the axially outer end portion of the seal tube portion 17.

  Therefore, a seal part can be formed in each of these pressure contact parts. That is, the seal cylinder part 17 of the joint main body 2 and the seal projection 23 of the inner ring 3 can form a first seal part in which the sealing force acts in the radial direction. And the inclined protrusion 24 of the inner ring 3 can form a second seal portion in which the sealing force acts in the axial direction.

  According to the method for manufacturing a resin pipe joint according to the present invention, instead of the elbow type resin pipe joint 1 (joint body 2), for example, the joint body is connected to the tube by the same connection structure as described above. It is also possible to manufacture a linear resin pipe joint (joint body) or a T-shaped resin pipe joint (joint body) that can be made, and the joint body is connected to the tube by a connection structure different from the above. It is also possible to manufacture a resin pipe joint (joint body) that can be connected.

  Next, as a method for manufacturing a resin pipe joint according to the present embodiment, a resin pipe joint 1, specifically, a manufacturing method for manufacturing the joint body 2 of the resin pipe joint 1 will be described.

  The manufacturing method includes a cavity 51 (cavity) for molding the wall portion of the resin pipe joint 1, a runner 52 for guiding the molten resin to the cavity 51, and a gate for communicating the cavity 51 and the runner 52. A preparatory process (see FIGS. 3, 4, and 5) for preparing the mold 50 having the structure 53, and an injection process for injecting the molten resin from the runner 52 into the cavity 51 through the gate 53.

  In the present embodiment, the mold 50 can be connected to a resin supply device 60 as shown in FIG. When the mold 50 and the resin supply device 60 are connected, the runner 52 is connected to a spool 59 into which the molten resin poured out from the resin supply device 60 flows. Here, as the molten resin, in order to manufacture the joint body 2 described above, a resin in which a fluororesin such as PFA, PVDF, ETFE, FEP, or PTFE is in a molten state is used.

  As shown in FIGS. 3, 4, and 5, the mold 50 is an outer mold body for defining the outer surface of the joint body 2 (the first end portion 11, the second end portion 12, and the connecting tube portion 13). 61A and an inner mold body 61B for defining the inner surface of the joint body 2 are provided.

  The outer mold main body 61A includes an outer mold 55 for defining the outer surface of the flow path wall 20 (mainly the connecting tube portion 13) of the fluid flow path 8 in the joint main body 2, and other parts (mainly the first main body). It has an outer mold (not shown) for defining the outer surfaces of the first end portion 11 and the second end portion 12). The outer mold 55 for defining the flow path wall 20 and the outer mold for defining the outer surface of the other part may be integrated or separate. The inner mold body 61B is disposed in the groove portion 62 of the outer mold body 61A so that the cavity 51 for molding the joint body 2 is formed.

  A mold 50 is formed on the inner mold 56 side of the outer mold 55 so as to open to the cavity 51 and an outer mold 55 including an inner surface 56 facing the cavity 51 for molding the flow path wall 20 of the joint body 2. And a recessed portion 57. A gate 53 is provided on the bottom 58 of the recess 57 so as to communicate with the cavity 51 via the internal space of the recess 57. The depth d of the recess 57 is set to 5% or more and 25% or less with respect to the numerical value of the wall thickness t of the flow path wall 20 (peripheral wall in the present embodiment) of the joint body 2 defined by the cavity 51. .

  The recess 57 is formed in the outer mold 55 between the outer mold body 61A and the inner mold body 61B facing each other in the cavity 51 for molding the flow path wall 20 of the joint body 2, that is, the outer mold body 61A and the inner mold body 61B. It is provided in the inner surface 56 side of the outer mold | type 55 so that it may open in the cyclic | annular space between them, and the space extended in a substantially linear form. The recess 57 is provided so as to communicate with a part of the cavity 51 inside the outer mold 55. In the present embodiment, the recessed portion 57 is the flow path wall 20 of the flow path changing portion of the fluid flow path 8 of the joint body 2 in the cavity 51 (specifically, the flow path wall of the bent portion 14 of the connecting cylinder portion 13). 20) is provided so as to open into a space for molding.

  As shown in FIG. 5, the opposing space has an interval w corresponding to the length of a line segment connecting the inner surface 56 of the outer mold 55 and the outer surface of the inner mold body 61B in the outer mold body 61A with the shortest distance. doing. Since the joint body 2 has a cylindrical shape with an L shape, the interval w is a joint body except for a part (mainly a portion for molding the first end portion 11 and the second end portion 12). The numerical value is substantially equal to the wall thickness t of the two flow path walls 20.

  The concave portion 57 is disposed near the center of the connecting cylinder portion 13 (closer to the bent portion 14). The concave portion 57 has a depth d with reference to the inner surface 56 of the outer mold 55 (more specifically, a linear portion). Here, the concave portion 57 includes a columnar or prismatic space as its internal space, and has a predetermined opening area. In addition, although the depth d of the recessed part 57 shall be substantially uniform in this embodiment, it is not limited to this. Moreover, the shape of the recessed part 57 may be other shapes such as a truncated cone shape or a truncated cone shape.

  The gate 53 has an opening smaller than the bottom 58 of the recess 57 (having an opening area smaller than the area of the bottom 58 (opening area of the recess 57)), and a shape similar to the shape of the bottom 58 (circular or It is preferably formed in a (corner shape). It is preferable that the gate 53 has substantially the same shape as the opening shape (flow channel cross-sectional shape) of the runner 52 and the opening area is set to be approximately the same as the opening area (flow channel cross-sectional area) of the runner 52. The gate 53 is disposed on the center side of the bottom 58 in the present embodiment.

  When the manufacturing method of the resin pipe joint 1 is used to manufacture the joint body 2 with the above-described configuration, the molten resin supplied from the resin supply device 60 is transferred from the runner 52 to the gate 53 in the injection step. It is possible to inject into the cavity 51 from the internal space of the recess 57 while injecting into the internal space of the recess 57 in the mold 50 (outer mold 55).

  Therefore, a molded product that forms the joint body 2 can be obtained by filling the molten resin into the internal space of the cavity 51 and the recess 57 and curing the filled molten resin by cooling. In this molded product, as shown in FIG. 6, due to the presence of the concave portion 57, the size does not hinder the function of the joint body 2 (resin pipe joint 1) in the vicinity of the gate 53 where the molten resin was injected. Projections, that is, pedestals 21 can be provided.

  Here, the molded product is composed of a resin filled in the cavity 51, a resin filled in the internal space of the recess 57, and an excess resin 65 remaining in a part of the runner 52. In the molded product, the cured resin has a layered shape that is in close contact with the orientation, and a resin layer located on the outermost layer of the resin layer structure (with a predetermined thickness (for example, 100 μm from the surface in contact with the mold 50). ) Layer) becomes the skin layer 66.

  Therefore, when a gate cutting jig is used for the molded product for gate cutting (removal of excess resin 65), for example, as shown in FIG. As a result, the adjacent resin layer (including the skin layer 66) in the molded product is peeled off so that a crack 68 is generated from the outer surface side (the side where the gate 53 is installed). Even in this case, since the gate cut can be performed at the place where the pedestal 21 is present in the molded product, the crack 68 can be prevented from reaching the flow path wall 20 from the vicinity of the place where the gate 53 is installed.

  That is, even when a crack 68 is generated from the outer surface side (gate 53 side) of the molded product due to the gate cut, a relatively large thickness is secured by the presence of the pedestal 21 at the crack 68 occurrence location in the molded product. As a result, the crack 68 can be generally accommodated in the pedestal 21. Therefore, it is possible to eliminate the formation of a through-hole connecting the outside and the inside (fluid channel 8) of the joint body 2 in the channel wall 20 of the joint body 2 due to the crack 68. Therefore, it is possible to prevent the fluid leakage caused by the through hole in the joint body 2. In particular, when the thickness t of the flow path wall 20 is set to 2 to 5 mm, it is effective if the pedestal 21 is provided.

  Moreover, the pedestal 21 has a height h corresponding to the depth d by setting the dimension range of the depth d of the recess 57. Therefore, if the height h of the pedestal 21 deviates from an appropriate dimension range and is lower than the dimension range, there is a possibility that a gate cut defect may be caused. If the height h is higher than the dimension range, Although sink marks occur on the inner surface of the flow path wall 20 located inside the pedestal 21 and there is a risk that smooth flow of fluid in the fluid flow path 8 may be hindered by the sink marks, the occurrence of these problems can be prevented.

  The resin pipe joint manufacturing method according to the present invention is not limited to the elbow-type resin pipe joint 1 described above, and the flow passage changing portion (bending portion, This is particularly useful when a resin pipe joint having a branching part, a joining part, etc.) is produced by injection molding.

  That is, when manufacturing a joint body of such a resin pipe joint by injection molding, if a gate is provided in the vicinity of the flow path changing portion of the fluid flow path in the joint body, a resin injection process into the mold The resin that has passed through the gate tends to flow vigorously in the front direction of the gate. As a result, the resin layer is easily oriented in the thickness direction of the flow path wall (the cross section direction of the fluid flow path) in the flow path wall of the joint body. When the resin layer is oriented in this way, the risk of a crack generated by peeling off the resin layer described above running in the thickness direction of the flow path wall during gate cutting is further increased.

  Here, in the mold (outer mold), a gate is arranged at the bottom of the recess provided on the inner surface facing the cavity for molding the flow path wall, and a pedestal is formed at the gate installation location in the joint body of the molded product If it is made, it can prevent that the above-mentioned crack penetrates to a fluid flow path, and it can prevent that the malfunction of fluid leakage arises.

DESCRIPTION OF SYMBOLS 1 Resin pipe joint 2 Joint main body 8 Fluid flow path 20 Flow path wall 50 Mold 51 Cavity 52 Runner 53 Gate 55 Outer mold 56 Inner surface of inner mold 57 Concave part 58 Bottom part of concave part d Depth of concave part Wall thickness

Claims (1)

In the method of manufacturing a resin pipe joint provided with a joint body having a fluid flow path for circulating a fluid,
Preparing a cavity for molding the flow path wall of the joint body, and a mold having a gate communicating with the cavity;
Injecting molten resin into the cavity through the gate,
The mold is
An outer mold including an inner surface facing the cavity, and a recess formed on the inner surface side of the outer mold so as to open to the cavity;
The gate has an opening smaller than the bottom of the recess, and is provided at the bottom of the recess so as to communicate with the cavity via the internal space of the recess;
The depth of the said recessed part is a manufacturing method of the resin-made pipe joints which are set to 5% or more and 25% or less with respect to the numerical value of the thickness of the flow-path wall of the said joint main body prescribed | regulated by the said cavity.

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