JP2013133777A - Manufacturing method of fuel distribution pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent occurrence of a burr at an opening of a fuel injection valve attaching hole in resin-molding of a fuel distribution pipe.SOLUTION: The fuel distribution pipe is manufactured by injecting molten resin from an injection gate 16 to a cavity 17 of a metal mold 11. The metal mold 11 includes a movable mold 12 and a fixed mold 13 having forming faces 12a and 13a, respectively, a fuel passage core 14 formed into a rod shape, a plurality of attaching part cores 15A to 15D, and the injection gate 16. The fuel passage core 14 is in a cantilevered state by both the movable and fixed molds 12 and 13 at its base end portion, and is arranged inside the movable and fixed molds 12 and 13 to be away from the forming faces 12a and 13a. The attaching part cores 15A to 15D are supported at their base end portions by both the molds 12 and 13, contacted to an outer circumference of the fuel passage core 14 at their tip ends, and arranged inside the movable mold 12 to be away from the forming face 12a, respectively. The injection gate 16 is provided to the fixed mold 13 to open in the forming face 13a corresponding to a tip end 15b of the attaching part core 15D arranged to correspond to the outer circumference of a tip end part 14b of the fuel passage core 14. The cavity 17 is formed in the metal mold 11 between each of the forming faces 12a and 13a, and each of the fuel passage core 14 and the attaching part cores 15A to 15D.

Description

  The present invention relates to a fuel distribution pipe provided in a fuel injection device of an engine and used to distribute fuel to a plurality of fuel injection valves provided corresponding to a plurality of combustion chambers. The manufacturing method of the fuel distribution pipe which becomes.

  Conventionally, as this type of technology, for example, a “method for producing a synthetic resin fuel distribution pipe” described in Patent Document 1 below is known. A fuel distribution pipe manufactured by this manufacturing method includes a fuel passage extending along the longitudinal direction, a fuel introduction port provided at one end, and a plurality of mounting holes arranged along the longitudinal direction and opened to the fuel passage. The mounting part. A fuel injection valve is attached to the attachment portion.

  This fuel distribution pipe is formed by injecting molten resin into a mold. FIG. 10 shows a mold 41 in a sectional view. FIG. 11 is a partial cross-sectional view of the mold 41 taken along line DD in FIG. The mold 41 includes a movable mold 42 and a fixed mold 43. When both molds 42 and 43 are closed, both molds 42a and 43a are formed on the inner sides of the molding surfaces 42a and 43a. A fuel passage core 44 is inserted from one side of 42 and 43. In this state, a cavity 45 is formed between the molding surfaces 42 a and 43 a and the outer peripheral surface of the fuel passage core 44. The fixed mold 43 is formed with an injection gate 46 for injecting molten resin into the cavity 45. The injection gate 46 has one convex portion at an intermediate position in the longitudinal direction of the fuel passage core 44 among the plurality of convex portions 47A, 47B, 47C formed on the movable die 42 corresponding to the plurality of mounting portions. Arranged on the side facing the portion 47B. Further, the center axis C3 of the injection gate 46 passes through the center axis C4 of the convex portion 47B and is disposed at a position intersecting with the center axis C5 of the fuel passage core 44.

  In this fuel distribution pipe manufacturing method, since the arrangement of the injection gate 46 is as described above, the boundary between the fuel passage and the attachment hole of the attachment portion, that is, the outer peripheral surface of the fuel passage core 44 and each convex portion 47A. Generation | occurrence | production of a burr | flash is prevented between the front-end | tip of -47C. That is, when the molten resin is injected into the cavity 45 at a high pressure through the injection gate 46, the fuel passage core 44 is pressed toward the convex portions 47A to 47C by the pressure of the molten resin. As a result, the fuel passage core 44 is brought into contact with the tips of the convex portions 47A to 47C to eliminate gaps between the fuel passage core 44 and the convex portions 47A to 47C. The burr is prevented from occurring at the opening of the mounting hole.

Japanese Patent Laid-Open No. 5-44594

  However, in the fuel distribution pipe manufacturing method described in Patent Document 1, the injection gate 46 is disposed corresponding to the intermediate position in the longitudinal direction of the fuel passage core 44. Accordingly, the tip end side of the fuel passage core 44 is in the state of the free end of the cantilever. For this reason, in the vicinity of the convex portion 47C located on the front end side of the fuel passage core 44, the fuel passage core 44 swings or decenters, and the outer peripheral surface of the core 44 and the convex portion 47C There was a possibility that the degree of adhesion with the tip would be reduced and a gap would be formed between them. When the gap is formed in this way, there is a concern that the resin flows into the gap and a burr is generated at the opening of the mounting hole of the molded fuel distribution pipe. Further, there is a possibility that deformation of each part of the molded fuel distribution pipe may occur due to the deflection or eccentricity of the fuel passage core 44.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a fuel distribution pipe that can prevent burrs from being generated at the opening of the mounting hole for the fuel injection valve when the fuel distribution pipe is molded with resin. It is to provide a manufacturing method.

  In order to achieve the above object, the invention described in claim 1 is a method of manufacturing a fuel distribution pipe for manufacturing a resin fuel distribution pipe by filling a mold cavity with a molten resin. The pipe has a fuel passage extending along the longitudinal direction inside, a pipe body part in which one end is closed and a fuel introduction port is provided at the other end, and a plurality of pipes are arranged along the longitudinal direction of the pipe body part, A molding hole having a mounting hole communicating with the fuel passage, a cylindrical mounting portion to which the fuel injection valve is mounted, and a mold having a molding surface for molding the surface shape of the fuel distribution pipe inside A mold, a base end portion is cantilevered to the molding die, and is disposed away from the molding surface inside the molding die, and a rod-shaped fuel passage core for molding a fuel passage; and a base end The part is supported by the mold and the tip is in contact with the outer periphery of the fuel passage core. A plurality of mounting portion cores for forming the mounting portion and the mounting hole, and the outer periphery of the tip end portion of the fuel passage core, which are arranged away from the molding surface inside the mold, are the most from the fuel introduction port. An injection gate provided on the molding die so as to open to the molding surface corresponding to the distal end of the mounting portion core for molding the mounting portion and the mounting hole apart from each other. A cavity is formed between the molding surface, the fuel passage core and the plurality of attachment cores, and the purpose is to inject molten resin from the injection gate into the cavity.

  According to the configuration of the above invention, the rod-shaped fuel passage core is cantilevered at the base end portion of the molding die, and the outer periphery of the distal end portion is in contact with the distal end of the corresponding attachment core, and Correspondingly, the opening of the injection gate is arranged. Accordingly, when the molten resin is injected from the injection gate into the cavity, the outer periphery of the tip of the fuel passage core is pressed by the pressure of the molten resin, and the outer periphery of the tip is pressed against the tip of the attachment core. The runout and eccentricity of the fuel passage core can be suppressed.

  In order to achieve the above object, according to a second aspect of the present invention, in the first aspect of the present invention, the plurality of attachment cores have their center axes separated from the center axis of the fuel passage core. The tip of the attachment core corresponding to the opening of the attachment hole with respect to the fuel passage and the opening of the injection gate with respect to the molding surface of the injection die are arranged so as to intersect with each other. It is intended that the fuel passage cores are arranged so as to face each other across the central axis of the fuel passage core.

  According to the configuration of the above invention, in addition to the operation of the invention according to claim 1, each of the mounting portion cores is arranged offset with respect to the fuel passage core. In this case, each attachment portion is arranged offset with respect to the tube main body portion. Therefore, there is a merit that the mountability of the fuel distribution pipe to the engine is improved when the fuel injection valve is attached to each attachment portion. On the other hand, since the attachment core is offset from the fuel passage core, when the fuel passage core is pressed by the pressure of the molten resin, the fuel passage core is attached to each of the attachments. A demerit that it is difficult to touch the tip of the core for the club is also conceivable. According to the configuration of the above invention, the tip of one mounting portion core and the opening of the injection gate are arranged so as to face each other across the central axis of the fuel passage core. The outer periphery of the tip of the core is stably pressed against the tip of the attachment core in the diameter direction.

  In order to achieve the above object, the invention described in claim 3 is the invention described in claim 2, wherein the mounting portion core has a convex portion for forming a mounting hole at a tip portion thereof. The convex portion includes a tip of the mounting portion core and a slope for forming an inclined surface in the mounting hole, and the slope of the convex portion is inclined with respect to the central axis of the mounting portion core. The central axis of the fuel passage core is located in the extending direction of the fuel cell.

  According to the configuration of the above invention, in addition to the operation of the invention according to claim 2, since the convex portion at the tip of each mounting portion core includes the inclined surface that forms the inclined surface of the mounting hole, the fuel passage The stress of the convex portion when the service core is pressed against the tip of each attachment portion core is dispersed by the slope.

  In order to achieve the above object, according to a fourth aspect of the present invention, in the second aspect of the present invention, a concave portion for molding the gate seat is formed on the molding surface of the molding die corresponding to the opening of the injection gate. The purpose is to provide it.

  According to the configuration of the above invention, in addition to the operation of the invention according to claim 2, since the recess for molding the gate seat is provided corresponding to the opening of the injection gate, the cavity is melted from the opening of the injection gate to the cavity. Resin becomes easy to inject. Further, immediately after the fuel distribution pipe is molded, when the runner made of the injection gate is cut out from the molded product, the runner is cut off at the gate seat.

  In order to achieve the above object, according to a fifth aspect of the present invention, in the invention of any one of the second to fourth aspects, the outer periphery of the fuel passage core and the tip of the mounting portion core are: The intent is to fit with the inlay.

  According to the configuration of the above invention, in addition to the operation of the invention according to any one of claims 2 to 4, the outer periphery of the fuel passage core and the tip of the mounting portion core are fitted in an inlay relationship. The difference between the two is less likely to occur.

  According to the first aspect of the present invention, the close contact between the fuel passage core and the tip of the attachment portion core is increased, and the molded fuel distribution pipe has a burr at the opening of the attachment hole of each attachment portion. Can be prevented.

  According to the second aspect of the invention, in contrast to the effect of the first aspect of the invention, the deflection and eccentricity of the fuel passage core can be more reliably suppressed, and the opening of the attachment hole of each attachment portion can be reduced. It is possible to more reliably prevent the occurrence of burrs.

  According to the invention described in claim 3, in addition to the effect of the invention described in claim 2, it is possible to reduce the stress of the convex portion of each mounting portion core, and to improve the durability of the convex portion. Can improve the durability of the core for each mounting portion.

  According to the invention described in claim 4, in addition to the effect of the invention described in claim 2, the filling time of the molten resin into the cavity can be shortened, and the body of the tube body is cut out by excising the runner. Can be prevented, and the merchantability of the fuel distribution pipe can be improved.

  According to the fifth aspect of the present invention, the deflection and eccentricity of the fuel passage core can be more reliably suppressed with respect to the effect of the second aspect of the present invention.

The front view which concerns on one Embodiment and shows fuel distribution piping. The AA sectional view taken on the line of FIG. 1 which shows the fuel distribution pipe according to the embodiment. The expanded sectional view along the BB line of Drawing 1 showing a fuel distribution pipe concerning the embodiment. Sectional drawing which shows the metal mold | die for shape | molding fuel distribution piping according to the embodiment. The expanded sectional view along CC line of Drawing 4 showing a metallic mold concerning the embodiment. FIG. 6 is a partially enlarged cross-sectional view of FIG. 5 showing the mold according to the embodiment. Sectional drawing which concerns on the same embodiment and cut | disconnects and shows the core for fuel passages perpendicularly to the center axis line. The side view which concerns on the same embodiment and shows the front-end | tip part of one core for attachment parts. The expanded sectional view which shows a part of fuel distribution piping immediately after shaping | molding concerning the embodiment. Sectional drawing which shows a metal mold | die concerning a prior art example. FIG. 11 is a partial cross-sectional view taken along line DD of FIG. 10 showing a mold according to a conventional example.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment embodying a method for manufacturing a fuel distribution pipe according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a front view of a fuel distribution pipe 1 according to this embodiment. FIG. 2 shows the fuel distribution pipe 1 by a cross-sectional view taken along line AA of FIG. FIG. 3 is an enlarged cross-sectional view of the fuel distribution pipe 1 cut along line BB in FIG. As shown in FIGS. 1 and 2, the fuel distribution pipe 1 includes a long pipe body 2 and a plurality (four) of attachment parts 3 </ b> A, 3 </ b> B, 3 </ b> C formed integrally with the pipe body 2. 3D and a pair of brackets 4 that are also formed integrally with the tube main body 2. The pipe body 2 has a fuel passage 5 extending along the longitudinal direction inside, the one end is closed, and the fuel inlet 6 is provided at the other end. The plurality of attachment portions 3A to 3D are arranged along the longitudinal direction of the tube main body portion 2 and have an attachment hole 7 communicating with the fuel passage 5, and are used for fitting and attaching a fuel injection valve (not shown). Form a cylinder. The brackets 4 are provided as a pair at positions close to both ends of the pipe body 2. Each bracket 4 is used for fixing the fuel distribution pipe 1 to the engine with a bolt or the like.

  As shown in FIGS. 1 and 3, in this embodiment, each of the attachment portions 3 </ b> A to 3 </ b> D is disposed offset upward from the center of the tube main body portion 2. The reason why the mounting portions 3A to 3D are arranged offset in this way is to improve the mountability of the fuel distribution pipe 1 to the engine in a state where the fuel injection valves are mounted to the mounting portions 3A to 3D.

  In this embodiment, nylon resin such as “PA66” or “PPA” is used as the resin material of the fuel distribution pipe 1. Further, in order to increase the strength and flexibility of the fuel distribution pipe 1, glass reinforcing fibers are mixed with nylon resin as a material.

  In FIG. 4, the metal mold | die 11 for shape | molding the fuel distribution pipe 1 is shown with sectional drawing. FIG. 5 shows an enlarged cross-sectional view of the mold 11 taken along the line CC in FIG. As shown in FIG. 4, the mold 11 includes a pair of a movable mold 12 and a fixed mold 13 as a molding mold, a rod-shaped fuel passage core 14 for molding the fuel passage 5, and each mounting portion 3A. -3D and a plurality of (four) cores 15A, 15B, 15C, 15D for molding the mounting holes 7 and an injection gate 16 provided in the fixed mold 13 are provided.

  As shown in FIG. 4, the movable mold 12 and the fixed mold 13 have molding surfaces 12 a and 13 a for molding the surface shape of the fuel distribution pipe 1 in a state where the mold 11 is closed. The fuel passage core 14 has a base end portion 14 a sandwiched between the movable mold 12 and the fixed mold 13 to be in a cantilever state, and a molding surface 12 a inside the movable mold 12 and the fixed mold 13. It is arranged away from 13a. The plurality of mounting portion cores 15 </ b> A to 15 </ b> D are supported at the base end portion 15 a by the movable die 12, the tip end 15 b is in contact with the outer periphery of the fuel passage core 14, and the tip end portion 15 c is molded inside the movable die 12. Located away from the surface 12a. The injection gate 16 corresponds to the outer periphery of the tip end portion 14b of the fuel passage core 14 and the tip 15b of the attachment portion core 15D for forming the attachment portion 3D and the attachment hole 7 farthest from the fuel introduction port 6. The fixed die 13 is provided so as to open to the molding surface 13a. In this mold closed state, in the mold 11, a cavity 17 is formed between the molding surfaces 12 a and 13 a of the movable mold 12 and the fixed mold 13, the fuel passage core 14, and the plurality of attachment cores 15 </ b> A to 15 </ b> D. Is formed. In order to manufacture the fuel distribution pipe 1, the molten resin is injected into the cavity 17 of the mold 11 from the injection gate 16 described above, thereby filling the cavity 17 with the molten resin.

  As shown in FIG. 5, the plurality of mounting portion cores 15 </ b> A to 15 </ b> D are arranged with respect to the fuel passage core 14 such that the center axis C <b> 1 intersects the center axis C <b> 2 of the fuel passage core 14. Are offset upward. As shown in FIGS. 3 and 5, the tip 15 b of the attachment portion core 15 D corresponding to the opening 7 a with respect to the fuel passage 5 of one attachment hole 7, and the injection gate 16 formed on the molding surface 13 a of the fixed die 13. Are disposed so as to face each other across the central axis C2 of the fuel passage core 14.

  As shown in FIGS. 4 and 5, each of the attachment portion cores 15 </ b> A to 15 </ b> D has a convex portion 15 d for forming the attachment hole 7 at the tip portion 15 c. The convex portion 15d includes tips 15b of the attachment portion cores 15A to 15D and inclined surfaces 15e and 15f for forming inclined surfaces 7b and 7c (see FIG. 3) in the attachment hole 7. The slopes 15e and 15f of the convex portions 15d of the mounting portion cores 15A to 15D are inclined with respect to the central axis C1 of the mounting portion cores 15A to 15D, and the fuel passage extends in the extending direction of the slopes 15e and 15f. The central axis C2 of the service core 14 is positioned.

  In this embodiment, in FIG. 5, when the angle formed by the extension line L1 extending in the extension direction of the slope 15e of the convex portion 15d and the extension line L2 extending in the extension direction of the slope 15f is “2α”, the injection gate 16 The opening 16a is disposed within the range of the angle 2α formed by the extension line L1 and the extension line L2. In particular, in this embodiment, the tip 15b of the one mounting portion core 15D and the opening 16a of the injection gate 16 are arranged on the dividing line L3 having the angle 2α. In other words, the tip 15b of one mounting portion core 15D and the opening 16a of the injection gate 16 are opposed to each other across the center axis C2 of the fuel passage core 14 on the bisector L3. Be placed.

  FIG. 6 is an enlarged cross-sectional view of a part of the mold 1 shown in FIG. As shown in FIGS. 5 and 6, corresponding to the opening 16 a of the injection gate 16, the molding surface 13 a of the fixed mold 13 is provided with a recess 18 for molding the gate seat 8 (see FIG. 3). Here, as shown in FIG. 6, the inner diameter D <b> 1 of the recess 18 can be set to “6 (mm)” that approximates the inner diameter of the injection gate 16, for example.

  FIG. 7 is a sectional view of the fuel passage core 14 cut perpendicularly to the central axis C2. In FIG. 8, the front-end | tip part 15c of one core 15A-15D for attachment parts is shown with a side view. As shown in FIGS. 7 and 8, the outer periphery of the fuel passage core 14 and the tips 15 b of the attachment portion cores 15 </ b> A to 15 </ b> D are configured to fit in an inlay relationship. That is, as shown in FIG. 8, the attachment portion cores 15 </ b> A to 15 </ b> D include a cylindrical tip portion 15 c for forming the attachment portions 3 </ b> A to 3 </ b> D, and a tip portion 15 c for forming the attachment hole 7. A convex portion 15d that is integrally formed first and a convex portion 15g that is integrally formed at the tip of the convex portion 15d are included. As shown in FIG. 7, the outer periphery of the fuel passage core 14 is formed with a recess 14c that receives the protrusion 15g of the protrusion 15d of the attachment portion cores 15A to 15D. As shown in FIG. 8, the convex 15g is fitted in the concave 14c.

  In this embodiment, in the above-described configuration, the molding surfaces 12a and 13a of the movable mold 12 and the fixed mold 13, the fuel passage core 14 and the plurality of mounting section cores 15A to 15D in the mold 11 which is closed. The molten resin is injected from the injection gate 16 into the cavity 17 formed between the two.

  According to the manufacturing method of the fuel distribution pipe of this embodiment described above, the rod-shaped fuel passage core 14 is cantilevered to the movable mold 12 and the fixed mold 13 at the proximal end portion 14a, and the distal end portion 14b. The opening 16a of the injection gate 16 is arranged so as to contact the tip 15b of one corresponding mounting portion core 15D and to correspond to the tip 15b. Therefore, when the molten resin is injected from the injection gate 16 into the cavity 17, the outer periphery of the tip portion 14b of the fuel passage core 14 is pressed by the pressure of the molten resin, and the outer periphery of the tip portion 14b is used for the mounting portion. Pressing against the tip 15b of the core 15D suppresses the deflection and eccentricity of the fuel passage core 14. For this reason, adhesion between the fuel passage core 14 and the tip 15b of each of the attachment portion cores 15A to 15D is increased, and the attachment hole 7 of each of the attachment portions 3A to 3D is formed with respect to the molded fuel distribution pipe 1. Generation | occurrence | production of the burr | flash in the opening 7a can be prevented. In addition, since the deflection and eccentricity of the fuel passage core 14 are suppressed, deformation of the inner peripheral surface of the fuel passage 5 of the molded fuel distribution pipe 1 can be suppressed.

  In this embodiment, since the attachment cores 15A to 15D are arranged offset with respect to the fuel passage core 14, each of the molded fuel distribution pipes 1 is different from the pipe main body 2. The attachment portions 3A to 3D are arranged offset. Therefore, there is an advantage that the mountability of the fuel distribution pipe 1 to the engine is improved when the fuel injection valves are attached to the attachment portions 3A to 3D. However, on the other hand, the attachment cores 15A to 15D are offset with respect to the fuel passage core 14, so that the fuel passage core 14 is pressed by the pressure of the molten resin. Further, a demerit that the fuel passage core 14 is difficult to contact the tip 15b of each of the attachment portion cores 15A to 15D is conceivable.

  Therefore, in this embodiment, the tip 15b of one attachment portion core 15D and the opening 16a of the injection gate 16 are disposed so as to face each other across the central axis C2 of the fuel passage core 14. Therefore, the outer periphery of the tip end portion 14b of the fuel passage core 14 is stably pressed against the tip end 15b of one attachment portion core 15D in the diameter direction. In this sense, the deflection and eccentricity of the fuel passage core 14 can be more reliably suppressed, and the generation of burrs at the openings 7a of the mounting holes 7 of the mounting portions 3A to 3D can be more reliably prevented. .

  In this embodiment, the convex part 15d of the front-end | tip part 15c of each attachment part core 15A-15D includes the inclined surface 15e which shape | molds the inclined surface 7b of the attachment hole 7. FIG. Accordingly, the stress of the convex portion 15d when the fuel passage core 14 is pressed against the tip 15b of each of the attachment portion cores 15A to 15D is dispersed by the inclined surface 15e. For this reason, the stress of the convex part 15d of each attachment part core 15A-15D can be reduced, and the durability of the convex part 15d and by extension the durability of each attachment part core 15A-15D are improved. Can be made.

  According to this embodiment, the concave portion 18 for molding the gate seat 8 corresponding to the opening 16a of the injection gate 16 is provided on the molding surface 13a. Accordingly, the molten resin can be easily injected into the cavity 17 from the opening 16a of the injection gate 16. For this reason, the filling time of the molten resin with respect to the cavity 17 can be shortened. Immediately after the fuel distribution pipe 1 is molded, an extra runner 9 made of the injection gate 16 remains in the gate seat 8 as shown in a partially enlarged sectional view in FIG. When the runner 9 is cut, the runner 9 is cut at the cutting portion 10 of the gate seat 8 as shown by a two-dot chain line in FIG. For this reason, it can prevent that the body (part of the meat | flesh of the pipe main-body part 2 is missing) by the excision of the runner 9 arises in the pipe main-body part 2, and improves the commercial property of the fuel distribution pipe 1. be able to.

  In this embodiment, since the outer periphery of the fuel passage core 14 and the tips 15b of the attachment portion cores 15A to 15D are fitted together in a spigot relationship, the difference between the two 14 and 15A to 15D hardly occurs. . In this sense, when the molten resin is injected into the cavity 17, the deflection and eccentricity of the fuel passage core 14 can be more reliably suppressed.

  In addition, this invention is not limited to the said embodiment, A part of structure can also be changed suitably and implemented in the range which does not deviate from the meaning of invention.

  (1) In the above-described embodiment, the four attachment portion cores 15A to 15D are used. However, the number of attachment portion cores may be appropriately increased or decreased.

  (2) In the above-described embodiment, the four attachment-portion cores 15A to 15D are provided separately from the mold 11, but all or part of the attachment-portion cores are provided integrally with the mold. Also good.

  The present invention can be used for manufacturing a fuel distribution pipe used in an engine fuel injection device.

DESCRIPTION OF SYMBOLS 1 Fuel distribution pipe 2 Pipe main-body part 3A Attachment part 3B Attachment part 3C Attachment part 3D Attachment part 5 Fuel passage 6 Fuel introduction port 7 Attachment hole 7a Opening 7b Inclined surface 7c Inclined surface 8 Gate seat 11 Mold 12 Movable type (molding type) )
12a Molding surface 13 Fixed mold (molding mold)
13a Forming surface 14 Fuel passage core 14a Base end portion 14b Tip portion 15A Mounting portion core 15B Mounting portion core 15C Mounting portion core 15D Mounting portion core 15a Base end portion 15b Tip end 15c Tip portion 15d Convex portion 15e Inclined surface 15f Inclined surface 15g Convex 16 Injection gate 16a Opening 17 Cavity 18 Concave portion C1 Center axis (for the mounting portion core)
C2 center axis (for fuel passage core)

Claims (5)

A fuel distribution pipe manufacturing method for manufacturing a resin fuel distribution pipe by filling a mold cavity with a molten resin,
The fuel distribution pipe has a fuel passage extending along the longitudinal direction inside, a pipe body portion having one end closed and a fuel introduction port provided at the other end, and the longitudinal direction of the tube body portion. A plurality of mounting holes, having a mounting hole communicating with the fuel passage, and a cylindrical mounting portion to which a fuel injection valve is mounted;
The mold includes a mold having a molding surface for molding the surface shape of the fuel distribution pipe, a base end portion of the mold being cantilevered by the mold, and the inside of the mold. A rod-shaped fuel passage core that is disposed away from the molding surface and for molding the fuel passage, a base end portion is supported by the molding die, and a tip is in contact with the outer periphery of the fuel passage core. A plurality of mounting portion cores for forming the mounting portion and the mounting hole, and an outer periphery of the tip end portion of the fuel passage core, which are arranged apart from the molding surface inside the mold. An injection gate provided on the molding die so as to open to the molding surface corresponding to the mounting portion farthest from the fuel introduction port and the tip of the mounting portion core for molding the mounting hole. The molding surface of the mold and the fuel passage in the mold Said cavity is formed between the child and the plurality of mounting portions for the core,
A method for manufacturing a fuel distribution pipe, wherein the molten resin is injected into the cavity from the injection gate.   The plurality of mounting portion cores are arranged offset with respect to the fuel passage core so that a central axis thereof is spaced apart from a central axis of the fuel passage core, The tip of the mounting portion core corresponding to the opening to the fuel passage and the opening to the molding surface of the molding die of the injection gate face each other across the central axis of the fuel passage core. The method for manufacturing a fuel distribution pipe according to claim 1, wherein the fuel distribution pipe is arranged as described above.   The mounting portion core has a convex portion for forming the mounting hole at a tip portion thereof, and the convex portion has an inclined surface at the tip end of the mounting portion core and the mounting hole. And the slope of the convex portion is inclined with respect to the central axis of the mounting portion core, and the central axis of the fuel passage core is positioned in the extending direction of the inclined surface. The method for manufacturing a fuel distribution pipe according to claim 2.   The method for manufacturing a fuel distribution pipe according to claim 2, wherein a recess for molding a gate seat is provided on the molding surface of the mold corresponding to the opening of the injection gate.   5. The method of manufacturing a fuel distribution pipe according to claim 2, wherein an outer periphery of the fuel passage core and a tip of the attachment portion core are fitted in an inlay relationship. .

Images