JP2010125813A - Method for manufacturing branched hose and branched hose precursor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a branched hose by which the branched hose can be simply manufactured without necessitating a washing process, and to provide a branched hose precursor. <P>SOLUTION: Injection molding of the branched hose precursor 6 is carried out by using a core 2 and an outer mold. The branched hose precursor 6 has the branched hose 1, a closure 17 for closing a communicating hole 15 of the branched hose 1 and a knob part 18 which is connected with a top face 17a facing a branched passage 12 of the closure 17 and extends to a branched passage 12 side. After the outer mold is released, gas 7 is injected between a hose body 11 and the core 2 to remove the core 2 from the branched hose precursor 6. The knob part 18 is grasped and is pulled out to the branched passage 12 side to rupture the closure 17 from a branched part 13 and then the knob part 18 as well as the closure 17 is taken out of the branched passage 12 to open the communicating hole 15. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a branch hose having a branch portion protruding from a hose body and a branch hose precursor.

  As shown in FIG. 11, the branch hose 9 includes a hose body 91 and a branch portion 92 branched from the hose body 91. The branch hose 9 is used, for example, as an air cleaner hose in an engine room of an automobile. The main passage formed inside the hose body 91 constitutes an intake passage. An air cleaner 98 is connected to the branch portion 92. Moreover, the branch part 92 can be utilized also as a connection part with silencers, such as a resonator.

A method of manufacturing a branch hose is disclosed in Patent Document 1. As shown in FIG. 12, an insert part 96 having a branch portion 92 and a closing portion 95 that closes one end thereof is prepared. When the hose body is blow-molded, the insert part 96 is joined to the outer periphery of the hose body 91. Thereafter, the closing part 95 of the insert part 96 is cut out with a drilling tool 98 such as a hole saw so that the hose body 91 and the branch part 92 are communicated with each other.
JP-A-5-278100 (paragraph number 0004)

  However, in Patent Document 1, when the closed portion 95 of the insert part 96 is cut out by the drilling tool 98, processing scraps or the like appear. For this reason, after excision, a step of washing the branch hose by air blow or the like is required.

  This invention is made | formed in view of this situation, and it makes it a subject to provide the manufacturing method of the branch hose which can manufacture a branch hose simply without requiring a washing | cleaning process, and a branch hose precursor. .

  The method for manufacturing a branch hose according to the present invention includes a hose body having a main passage therein, and a branch portion branched from the hose body and having a branch passage therein, the main passage and the branch passage Is a method of manufacturing a branch hose that is communicated by a communication hole formed between the hose body and the branch portion, and is formed on the inner peripheral surface of the hose body in the space formed in the outer mold. A cavity forming step in which a core having a matching shape is arranged to form a cavity between the outer mold and the core; a molding material is injected into the cavity; the branch hose; and the communication hole An injection step of forming a branch hose precursor having a closed portion that closes the closed passage and a knob portion that is connected to a top surface of the closed portion facing the branch passage and extends toward the branch passage; Outside to remove the outer mold A mold releasing step, a middle core mold releasing step of injecting a gas between the hose body and the core of the branched hose precursor from which the outer mold has been removed, and removing the core from the hose body; By grasping the knob portion of the branch hose precursor and pulling it to the branch passage side, the blocking portion is broken from the branch portion, and the knob portion is taken out from the branch passage together with the blocking portion, thereby the communication And a drilling step for opening the hole.

  The closing part has an outer peripheral part connected to the branch part and a central part formed radially inward of the outer peripheral part, and the thickness of the outer peripheral part is the thickness of the central part and the hose. It is preferable that the thickness is smaller than the thickness of the main body (claim 2).

  A branch hose precursor according to the present invention closes a hose body having a main passage inside, a branch portion branched from the hose body and having a branch passage inside, and the main passage and the branch passage. It has a closed part and a knob part connected to the top face of the closed part facing the branch passage and extending toward the branch passage (Claim 3).

  The closing part has an outer peripheral part connected to the branch part and a central part formed radially inward of the outer peripheral part, and the thickness of the outer peripheral part is the thickness of the central part and the hose. It is preferable that the thickness is smaller than the thickness of the main body (claim 4).

  It is preferable that the knob portion is connected to an eccentric position that is deviated in a radial direction from a center position of the top surface of the closing portion.

  It is preferable that the knob portion is inclined so as to approach a proximity portion closest to the eccentric position in the outer peripheral portion with respect to a direction from the branch portion toward the main passage.

  According to the method for manufacturing a branch hose according to the present invention, the branch hose precursor is formed by injection molding using a core and an outer mold. The branch hose precursor has the shape of a branch hose, and further has a closed portion that closes the communication hole and a knob portion that protrudes from the closed portion toward the branch passage. For this reason, when gas is injected between the hose body and the core after the outer mold is removed from the branch hose precursor, the gas does not leak from the communication hole to the branch portion. Therefore, gas can be filled between the core and the hose body, and the core can be released from the hose body.

  Moreover, the knob part which protrudes in the branch passage side is formed in the top surface of the obstruction | occlusion part. By inserting a tool or the like into the branch passage and pulling the knob portion toward the branch passage, the closed portion is broken between the branch portion and the communication hole is opened. Therefore, the drilling process for opening the communication hole can be simplified.

  Further, the closing portion together with the knob portion can be taken out from the branch passage, and the knob portion and the closing portion can be collected as an integrated product. For this reason, excision waste is not discharged and it is not necessary to carry out washing in a subsequent process. Therefore, the number of manufacturing steps of the branch hose can be reduced, and the branch hose can be manufactured simply.

  When the thickness of the outer peripheral part in the closed part is thinner than the thickness of the central part and the hose body in the closed part, when the grip part is gripped and the closed part is pulled out to the branch passage side, the closed part becomes the branched part. Break at the boundary. Therefore, there is no possibility that burrs are generated on the fracture surface of the branch portion, and a deburring step is not necessary. Also, a molding material in which the flow resistance of the molding material is generated at the part forming the outer peripheral part of the closed part of the cavity, and the temperature of the molding material flowing into the part forming the closed part of the cavity flows into the other part of the cavity. The temperature rises more easily. Therefore, when the molding material is a rubber material, the molding material that forms the blocking portion is vulcanized more than the molding material that forms the other portion, and loses elasticity and becomes hard. Therefore, the outer peripheral part of the closing part is more easily broken.

  The branch hose precursor according to the present invention includes a closed portion that closes between the main passage and the branch passage, and a knob portion that is connected to a top surface of the closed portion facing the branch passage and extends toward the branch passage. By inserting a tool or the like into the branch passage and pulling the knob toward the branch passage, the closed portion breaks from the branch portion, and a communication hole that connects the main passage and the branch passage is formed between the hose body and the branch portion. It is formed. Therefore, the drilling process for opening the communication hole can be simplified.

  Further, the closing portion together with the knob portion can be taken out from the branch passage, and the knob portion and the closing portion can be collected as an integrated product. For this reason, excision waste is not discharged and it is not necessary to carry out washing in a subsequent process. Therefore, the number of manufacturing steps of the branch hose can be reduced, and the branch hose can be manufactured simply.

  The branch hose precursor is formed by injection molding a molding material into a cavity formed between the inner core and the outer mold. After releasing the outer mold, the core can be easily pulled out from the branch hose precursor by injecting a gas between the center core and the hose body of the branch hose precursor.

  When the thickness of the outer peripheral part in the closed part is thinner than the thickness of the central part and the hose body in the closed part, when the grip part is gripped and the closed part is pulled out to the branch passage side, the closed part becomes the branched part. Break at the boundary. Therefore, there is no possibility that burrs are generated on the fracture surface of the branch portion, and a deburring step is not necessary. Also, a molding material in which the flow resistance of the molding material is generated at the part forming the outer peripheral part of the closed part of the cavity, and the temperature of the molding material flowing into the part forming the closed part of the cavity flows into the other part of the cavity. The temperature rises more easily. Therefore, when the molding material is a rubber material, the molding material that forms the blocking portion is vulcanized more than the molding material that forms the other portion, and loses elasticity and becomes hard. Therefore, the outer peripheral part of the closing part is more easily broken.

  When the knob portion is connected to an eccentric position that is radially deviated from the center position of the top surface of the closing portion, when the knob portion is pulled toward the branch passage, it is close to the eccentric position of the outer peripheral portion. A larger load is applied to the proximity portion than the other portions of the outer peripheral portion. For this reason, the proximity portion is likely to break prior to the other portions. When the proximity portion breaks, the other portions of the outer peripheral portion are sequentially broken starting from the broken proximity portion, and the closed portion is separated from the inner peripheral surface of the branch portion. Therefore, the tensile force is easily concentrated on a part of the outer peripheral portion between the closed portion and the inner peripheral surface of the branch portion, and the closed portion can be separated from the branch portion with a small tensile force.

  When the knob portion is inclined so as to be close to the proximity portion of the outer peripheral portion with respect to the direction from the branch portion to the communication hole, when the knob portion is pulled toward the branch passage, The load concentrates effectively in the proximity area. For this reason, the closed portion can be separated from the branch portion with a small pulling force.

  In the branch hose manufacturing method of the present invention, the branch hose precursor is injection-molded with a molding material in a cavity in a mold. The mold includes an outer mold and an inner core, and a cavity having a shape suitable for the branch hose precursor is formed between the outer mold and the inner core. The branch hose precursor includes, in addition to the portion having the shape of the branch hose, a blocking portion that blocks the communication hole of the branch hose, and a knob portion that protrudes from the blocking portion toward the branch passage inside the branch portion of the branch hose. It has. After the branch hose precursor is injection molded, the outer mold is released.

  Next, gas is injected between the hose body and the core of the branch hose precursor. At this time, since the communication hole between the main passage and the branch passage is closed at the closing portion, the gas is filled between the hose body and the core, the branch hose precursor is elastically deformed, The core can be released from the hose body. Thereafter, the knob portion is pulled out to the branch passage side. As a result, the closed portion to which the knob portion is connected is broken from the branch portion and taken out of the branch portion through the branch passage.

  The molding material injected into the cavity may be any material that can be elastically deformed radially outward of the hose body by gas injection. For example, a rubber material, a soft resin material such as TPO, or the like is used.

  The gas injected between the hose body and the core is preferably a compressed gas. This is because the center core can be easily released from the hose body. The gas is not particularly limited, for example, using air or the like.

  The means for pulling the knob is, for example, a tool such as a pliers, a hand, or the like.

  Here, the blocking part and the knob part formed in the branch hose precursor will be further described. The outer peripheral part of the closing part is connected to the inner peripheral surface of the branch part. The outer peripheral part of the closing part is preferably thinner than the central part on the center side of the outer peripheral part in the closing part. The wall thickness of the outer peripheral portion of the closing portion is preferably 0.3 to 0.7 mm. In this case, at the time of injection molding, a sufficient flow space for the molding material to the closed portion molding portion of the cavity is secured, and the molding material sufficiently flows into the closed portion molding portion. For this reason, the molding yield of the closing portion and the knob portion is improved. Moreover, it becomes easier to fracture | rupture an outer peripheral part between branch parts.

  The width of the outer peripheral portion of the closing portion is preferably 0.2 to 0.4 mm. In this case, when the knob portion is pulled out to the branch passage side, the outer peripheral portion is more easily broken between the branch portion. Further, at the time of injection molding, the molding material sufficiently flows from the outer peripheral portion molding portion of the cavity to the entire closing portion molding portion, and the molding yield of the closing portion and the knob portion is improved.

  The knob portion may be a rod-shaped body. This is because the knob portion, which is a rod-shaped body, is easily bent when the outer mold is released, and the frictional resistance with the outer mold can be reduced. When the knob portion is a rod-like body, the radial cross-sectional shape of the knob portion is a polygon such as a circle, an ellipse, or a rectangle.

  When the knob portion is projected toward the closing portion, the knob portion may pass through the center position of the closing portion, and the tip end portion and the base end portion of the knob portion may be disposed on both sides of the center position. In this case, the knob portion has a length sufficient to be gripped in the branch passage, and the knob portion is easily gripped with a tool or the like.

  The thickness of the knob is preferably 5 to 10 mm. In this case, when the outer mold is released from the knob portion, the knob portion can be prevented from being pulled and cut by the outer mold. Moreover, a load can be effectively applied to the outer peripheral portion of the closing portion.

  It is preferable that the length from the front-end | tip part of a knob part to a base end part is 15-30 mm. In this case, it becomes easy to grip the knob portion with a tool or the like. Further, when the outer mold is released from the knob portion, the knob portion can be prevented from being pulled and cut by the outer mold.

  The knob portion may extend in parallel with the branch portion, or may be inclined with respect to the branch portion. It is desirable that the knob portion be inclined so as to be close to the proximity portion closest to the eccentric position G in the outer peripheral portion. The eccentric position G is a position that is radially deviated with respect to the center position C that is the center in the radial direction of the blocking portion.

  The inclination angle α of the knob portion with respect to the branch portion is preferably 25 to 40 °. In this case, the tensile force applied to the knob portion is effectively transmitted to the outer peripheral portion of the closing portion, and the outer peripheral portion easily breaks between the branch portion.

  It is preferable that a proximity portion of the outer peripheral portion of the closing portion is located on an extension line from the distal end portion to the proximal end portion of the knob portion. In this case, when the knob portion is pulled toward the branch passage, the load can be concentrated on the proximity portion, and the outer peripheral portion and the branch portion can be easily broken.

  The manufactured branch hose is used for, for example, an air cleaner hose, an intake hose, a resonator, a ventilation hose, a vacuum hose and the like of an intake system of an internal combustion engine.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a side view of a branch hose. 2 shows a cross-sectional view taken along the line AA in FIG. As shown in FIGS. 1 and 2, the branch hose 1 includes a hose body 11 having a main passage 10 inside, and a branch portion 13 branched from the hose body 11 and having a branch passage 12 inside. The main passage 10 and the branch passage 12 communicate with each other through a communication hole 15 formed between the hose body 11 and the branch portion 13. The hose body 11 has a straight portion 11b and a bent portion 11c bent with respect to the longitudinal direction of the straight portion 11b. The branch part 13 is connected to the straight part 11b. A bellows portion 16 extending and contracting in the longitudinal direction is formed in the vicinity of the straight portion 11b of the bent portion 11c.

Hereinafter, the manufacturing method of a branch hose is demonstrated for every process.
(Cavity formation process)
FIG. 3 shows a cross-sectional view of a mold for forming a branch hose precursor that is an intermediate of the branch hose. 4 is a cross-sectional view taken along line BB in FIG. As shown in FIG. 9 described later, the branch hose precursor 6 has a portion having the shape of the branch hose 1, and a blocking portion 17 and a knob portion 18 formed inside the branch portion 13 of the branch hose 1. As shown in FIG. 4, the mold 4 includes a center core 2 and an outer mold 3. A cavity 5 for forming a branch hose precursor is formed between the middle core 2 and the outer mold 3 by arranging the middle core 2 in a space 50 formed in the outer mold 3. The cavity 5 includes a main body forming cavity 51, a branch forming cavity 53, a closing portion forming cavity 57, and a knob forming cavity 58.

  As shown in FIGS. 3 and 4, the core 2 has a shape that matches the inner peripheral surface of the hose body 11. One end portion 28 of the core 2 protrudes from the outer mold 3 to the outside. As shown in FIG. 4, the outer mold 3 has an outer molding surface 35 and a branched inner molding surface 36. The outer molded surface 35 has a main body outer molded surface 35a having a shape that matches the outer peripheral surface of the hose body 11 of the branch hose 1, and a branched outer molded surface 35b that has a shape that matches the outer peripheral surface of the branch portion 13 of the branch hose 1. And have.

  The outer mold 3 includes a first outer mold 31 and a second outer mold 32. The first outer mold 31 has a molding surface that molds the upper portion of the hose body 11 among the outer body molding surface 35a, a branch outer molding surface 35b, and a branch inner molding surface 36. The second outer mold 32 has a molding surface for molding the lower part of the hose body 11 of the main body outer molding surface 35a.

  The main body outer molding surface 35a surrounds the space 50 having a shape that matches the outer shape of the hose main body 11. Inside the space 50, the core 2 is disposed. A body molding cavity 51 having a shape that matches the hose body 11 is interposed between the body outer molding surface 35 a and the core 2.

  As shown in FIG. 5, the branched outer molding surface 35 b surrounds the cylindrical space, and on the inner side, the branched inner molding surface 36 formed on the circumferential surface of the columnar body faces the body molding cavity 51. Is approaching. That is, the branched inner molding surface 36 is formed from the base end portion 36a toward the distal end portion 36b on the main body molding cavity 51 side. Between the branch outer molding part 35b and the branch inner molding surface 36, a cylindrical branch part molding cavity 53 having a shape matching the branch part 13 is interposed.

  The branch inner molding surface 36 surrounds the closing portion molding cavity 57 and the knob portion molding cavity 58. The closing portion forming cavity 57 is a cavity for forming the closing portion 17, is formed between the distal end portion 36 b of the branch inner forming surface 36 and the core 2, and communicates with the branch portion forming cavity 53. . The blocking portion 17 is a portion that blocks the communication hole 15 as will be described later. The knob portion forming cavity 58 is formed from the closing portion forming cavity 57 toward the base end portion 36 a side of the branched inner forming surface 36.

(Injection process)
Next, as shown in FIG. 4, a rubber material mixed with a vulcanizing material is injected into the cavity 5 from a gate (not shown) provided in the outer mold 4 and filled. Next, the rubber material in the cavity 5 is heated and vulcanized. Thereby, the branch hose precursor 6 is molded.

  The branch hose precursor 6 has a hose body 11, a branch part 13, a blocking part 17, and a knob part 18. The hose body 11 and the branch part 13 constitute the branch hose 1.

  As shown in FIGS. 5 and 6, the closing portion 17 closes the communication hole 15 formed between the main passage 10 inside the hose body and the branch passage 12 inside the branch portion 13. The blocking portion 17 has a top surface 17 a facing the branch passage 12 and a bottom surface 17 b facing the main passage 10. The bottom surface 17b is flush with the inner surface of the hose body 11.

  The blocking part 17 has a central part 17c and an outer peripheral part 17d connected to the branch part 13 on the outer peripheral side of the central part 17c. The top surface 17a of the central portion 17c is a flat surface. The thickness A of the central portion 17c is 1.5 to 2.5 mm. The outer peripheral portion 17d has a thickness B of 0.3 to 0.7 mm, and the outer peripheral portion 17d has a width D of 0.2 to 0.4 mm. Between the central portion 17c and the outer peripheral portion 17d, a thickness changing portion 17f that gradually increases the thickness from the outer peripheral portion 17d toward the central portion 17c is formed. The inclination angle α of the thickness changing portion 17f with respect to the branching portion 13 is 25 to 40 °. The thickness of the hose body 11 is 0.8 to 2.5 mm.

  The knob portion 18 is a rod-shaped body having a circular cross section, and is connected to the top surface 17a of the central portion 17c of the closing portion 17 at the base end portion 18a. The length E of the knob portion 18 is 15 to 30 mm, and the thickness F of the knob portion is 4 to 8 mm. The connection position of the base end portion 18a of the knob portion 18 is an eccentric position G that is offset in the radial direction from the radial center position C of the top surface 17a. In this example, the eccentric position G is located on the outer peripheral edge of the central portion 17c.

  The knob portion 18 is inclined so as to approach the proximity portion 17e closest to the eccentric position G in the outer peripheral portion 17d. The inclination angle α of the knob portion 18 with respect to the branch portion 13 is 25 to 40 °, and is the same as the inclination angle of the thickness changing portion 17e of the closing portion 17. The knob portion 18 extends toward the distal end side of the branching portion 13 around the proximity portion 17e of the outer peripheral portion 17d of the closing portion 17. A tip end portion 18 b of the knob portion 18 is disposed inside the branch passage 12. As shown in FIG. 6, when the knob portion 18 is projected toward the top surface 17 a of the closing portion 17, the knob portion 18 crosses the center position C of the closing portion 17. That is, the central position C of the closing portion 17 is located between the proximal end portion 18a and the distal end portion 18b of the knob portion 18. A proximity portion 17e of the outer peripheral portion 17d of the closing portion 17 is located on an extension line from the distal end portion 18b of the knob portion 18 to the proximal end portion 18a.

  Next, the rubber material filling the cavity 50 is heated at 180 ° C. to vulcanize the rubber material.

(Outside mold release process)
Next, as shown in FIG. 4, the outer mold 3 is released from the branch hose precursor 6. Specifically, the first outer mold 31 is moved upward and the second outer mold 32 is moved downward.

  As shown in FIG. 5, since the knob portion 18 is inclined with respect to the axial direction of the branch portion 13, an undercut portion 31 a is formed below the knob portion 18 of the first outer mold 31. However, since the knob portion is made of a rubber material, it has elasticity. For this reason, the knob part 18 can be elastically deformed by the movement of the first outer mold 31, and the undercut part 31 a can be pulled out from the lower side of the knob part 18.

(Core release process)
Next, as shown in FIG. 7, a gas injection jig 70 is attached to the end portion of the branch hose precursor 6 on the straight portion 11 b side of the hose body 11. The jig 70 has a fitting portion 71 and a supply port 72. The fitting portion 71 is annular and has substantially the same shape as the end portion of the hose body 11 on the linear portion 11b side. The fitting portion 71 is fitted to the end portion and is hermetically fixed by bolting or clamping. . The supply port 72 is connected to a gas supply source such as a blower. The gas 7 is supplied from the supply port 71 to the end of the hose body 11, the gas 7 is injected between the hose body 11 and the core 2, and the core 2 is pulled out from the hose body 11. As shown in FIG. 8, since the branch hose precursor 6 is made of a rubber material, the hose body 11 is elastically expanded radially outward by the injection of the gas 7, so that the core 2 Leave. In this state, the core 2 can be easily pulled out of the hose body 11 by pulling the tip end portion 28 (FIG. 3) of the core 2.

(Drilling process)
Next, as shown in FIG. 9, the tool 8 is inserted into the branch passage 12 inside the branch portion 13 of the branch hose precursor 6, and the knob portion 18 is pulled toward the branch passage 12. The tool 8 is a pliers. As shown in FIG. 10, the proximal end portion 18 a of the knob portion 18 is connected to the closing portion 17. Due to the pulling force of the knob portion 18, a breaking force is generated in the outer peripheral portion 17 d of the closing portion 17. And breaking force concentrates on the boundary part between the outer peripheral part 17d and the branch part 13, and it fractures | ruptures in a boundary part.

  Here, the base end portion 18 a of the knob portion 18 is fixed to an eccentric position G that is offset in the radial direction from the radial center position C of the top surface 17 a of the closing portion 17. Further, the knob portion 18 is inclined so as to approach the proximity portion 17e closest to the eccentric position G in the outer peripheral portion 17d. For this reason, the breaking force concentrates on the proximity portion 17e of the outer peripheral portion 17d, and the proximity portion 17e breaks. When the proximity portion 17e breaks, it gradually breaks around it, and the entire outer peripheral portion 17d breaks between the branch portion 13. As a result, the closing portion 17 is taken out together with the knob portion 18 through the branch passage 12. Further, a communication hole 15 is opened at a portion where the outer peripheral portion 17d is broken, and the branch passage 12 inside the branch portion 13 and the main passage 10 inside the hose body 11 communicate with each other. The branch hose 1 is obtained by the above.

  In this example, as shown in FIG. 8, the communication hole 15 of the branch hose 1 is closed by a closing portion 17. For this reason, when the gas 7 is injected between the hose body 11 and the core 2, the gas 7 does not leak from the communication hole 15 to the branch portion 13. Therefore, the core 7 can be easily released from the hose body 11 by filling the gas 7 between the core 2 and the hose body 11.

  Further, as shown in FIG. 10, a knob portion 18 that protrudes toward the branch passage is formed on the top surface 17 a of the closing portion 17. By inserting the tool 8 into the branch passage 12 and pulling the knob portion 18 toward the branch passage 12, the blocking portion 17 is broken between the branch portion 13 and the communication hole 15 is opened. Therefore, the process of drilling the communication hole can be simplified as compared with the case of cutting the communication hole 15 with a cut-and-sew.

  Further, the closing portion 17 together with the knob portion 18 can be taken out from the branch passage 12, and the knob portion 18 and the closing portion 17 can be collected as an integrated product. For this reason, excision waste is not discharged and it is not necessary to carry out washing in a subsequent process. Therefore, the number of manufacturing steps of the branch hose 1 can be reduced, and the branch hose 1 can be manufactured simply.

  The thickness of the outer peripheral portion 17 d of the closing portion 17 is thinner than the thickness of the central portion 17 c of the closing portion 17 and the thickness of the hose body 11. For this reason, when the knob portion 18 is gripped by the tool 8 and the closing portion 17 is pulled out to the branch passage 12 side, the closing portion 17 is broken at the boundary with the branch portion 13. Therefore, there is no fear that burrs will occur on the fracture surface, and no deburring step is required. Further, the flow resistance of the rubber material is generated in the outer peripheral portion molding portion in the closing portion molding cavity 57, and the temperature of the rubber material flowing into the outer peripheral portion molding portion is higher than that of the rubber material flowing into the other portion of the cavity 5. Even temperature rises easily. Therefore, the vulcanization of the rubber material forming the closed portion 17 proceeds more than the rubber material forming the other portion, and the rubber material forming the closed portion 17 is hardened. Therefore, the outer peripheral part 17d of the closing part 17 is more easily broken between the branch part 13 and the outer part 17d.

  The knob portion 18 is connected to an eccentric position G that is offset in the radial direction from the center position C of the top surface 17 a of the closing portion 17. For this reason, when the knob 18 is pulled toward the branch passage 12, a larger load is applied to the proximity portion 17 e near the eccentric position G of the outer peripheral portion 17 d than the other portions of the outer peripheral portion 17 d. For this reason, the proximity portion 17e close to the eccentric position G is likely to break prior to other portions. When the knob portion 18 continues to be pulled, the vicinity of the proximity portion 17e is sequentially broken starting from the broken proximity portion 17e, and the entire outer peripheral portion 17d is separated from the branching portion 13. Therefore, the tensile force is easily concentrated on a part of the outer peripheral portion 17d, and the closing portion 17 can be separated from the branch portion 13 with a small tensile force.

  The knob portion 18 is inclined so as to approach the proximity portion 17e of the outer peripheral portion 17d with respect to the direction from the branch passage 12 toward the main passage 10. For this reason, when the knob part 18 is pulled to the branch part 13 side, the load is effectively concentrated on the proximity part 17e. For this reason, the closing part 17 can be separated from the branch part 13 with a smaller pulling force.

It is a side view of the branch hose based on Example 1 of this invention. It is an AA arrow line sectional view of Drawing 1. 1 is a sectional view of a mold according to Example 1. FIG. It is a BB arrow line sectional view of Drawing 3. FIG. 3 is a cross-sectional view of a mold in the vicinity of a branch portion forming cavity according to Example 1; FIG. 6 is a cross-sectional view taken along line HH in FIG. 5. It is explanatory drawing for showing the method of inject | pouring gas between the hose main body and branch core of a branch hose precursor based on Example 1. FIG. It is explanatory drawing which shows the method of pulling out a center core from the hose main body based on Example 1. FIG. 1 is a cross-sectional view of a branch hose precursor according to Example 1. FIG. It is explanatory drawing which shows the method which removes the obstruction | occlusion part and knob part based on Example 1 from a branch part. It is a front view of a branch hose. It is explanatory drawing which shows the manufacturing method of the branch hose based on a prior art example.

Explanation of symbols

1: branch hose, 2: core, 3: outer mold, 4: mold, 5: cavity, 6: branch hose precursor, 7: gas, 8: tool, 10: main passage, 11: hose body, 12 : Branch passage, 13: branch portion, 15: communication hole, 16: bellows portion, 17: closed portion, 17a: top surface, 17b: bottom surface, 17c: center portion, 17d: outer peripheral portion, 17e: proximity portion, 17f: Thickness changing portion, 18: knob portion, 18a: proximal end portion, 18b: distal end portion, 31: first outer mold, 32: second outer mold, 33: third outer mold, 34: fourth outer mold, 50: Space part, 51: Cavity for forming hose body, 53: Cavity for forming branch part, 57: Cavity for forming closed part, 58: Cavity for forming knob part, 70: Jig, C: Center position of closed part, G: Eccentric position of occlusion.

Claims (6)

A hose body having a main passage inside, and a branch portion branching from the hose body and having a branch passage inside, the main passage and the branch passage being between the hose body and the branch portion A method of manufacturing a branch hose that communicates with a communication hole formed in
A cavity forming step of disposing a core having a shape matching the inner peripheral surface of the hose body in the space formed in the outer mold, and forming a cavity between the outer mold and the core;
A molding material is injected into the cavity, and the branch hose, a closed portion that closes the communication hole, and a knob portion that is connected to a top surface of the closed portion facing the branch passage and extends toward the branch passage. An injection step of forming a branched hose precursor having,
An outer mold releasing step of removing the outer mold from the branch hose precursor;
A core releasing process in which gas is injected between the hose body and the core of the branched hose precursor from which the outer mold has been removed, and the core is removed from the hose body;
By grasping the knob portion of the branch hose precursor and pulling it to the branch passage side, the blocking portion is broken from the branch portion, and the knob portion is taken out from the branch passage together with the blocking portion, A method for manufacturing a branch hose, comprising: a drilling step of opening the communication hole.   The closing part has an outer peripheral part connected to the branch part and a central part formed radially inward of the outer peripheral part, and the thickness of the outer peripheral part is the thickness of the central part and the hose. The manufacturing method of the branch hose of Claim 1 thinner than the thickness of a main body.   A hose body having a main passage inside, a branching portion branched from the hose body and having a branching passage inside, a closing portion closing the space between the main passage and the branching passage, and the branching of the closing portion A branch hose precursor comprising a knob portion connected to a top surface facing the passage and extending toward the branch passage.   The closing part has an outer peripheral part connected to the branch part and a central part formed radially inward of the outer peripheral part, and the thickness of the outer peripheral part is the thickness of the central part and the hose. The branch hose precursor according to claim 3, which is thinner than the thickness of the main body.   The branch hose precursor according to claim 3 or 4, wherein the knob portion is connected to an eccentric position that is offset in a radial direction from a center position of the top surface of the closing portion.   The branch hose precursor according to claim 5, wherein the knob portion is inclined so as to approach a proximity portion closest to the eccentric position in the outer peripheral portion with respect to a direction from the branch portion toward the main passage.

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