JP2017144703A - Manufacturing method of resin fuel tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a resin fuel tank suppressing local changes of wall thickness of the fuel tank without needs for composite mechanism.SOLUTION: By size enlarging a sheet body 100 in a cavity 44 having a recess 46 on a bottom surface 44A, the sheet body 100 adheres the recess 46 and an extra length portion 102 is formed. With the state, a built-in component 18 is arranged on the recess 46 and an injection resin 64 is injected from an injection unit 56 to the recess 46. Thereby the extra length portion 102 of the sheet body 100 adheres a lower surface side of a fitting seat body 26 and goes around a rear side of a collar part 32 of an undercut shape part 28 provided on the lower surface and a caulking part 38 can be formed. In other words, a resin fuel tank can be formed by a simple device construction without largely changing wall thickness locally.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a method for manufacturing a resin fuel tank.

  Conventionally, when a resin fuel tank for automobiles is manufactured, a built-in component is attached to a sheet body made of a molten resin shaped with respect to a cavity of a split mold. In this case, a part of the sheet body (molten resin) is inserted into a hole formed in the mounting seat of the built-in component and pushed out. The built-in parts were attached to the seat body by sandwiching the attachment seat between the expanded portion located at the top of the seat and the seat body located at the bottom of the seat (hereinafter, this clamping portion is referred to as the “crimped portion”) Sometimes). In this case, a part of the sheet body (molten resin) is collected from the surroundings and inserted into the hole of the mounting seat to form the crimped portion, so that the thickness of the sheet body (fuel tank) changes locally. There was a risk.

  Therefore, by pre-blowing in the opposite direction before shaping the sheet body into the cavity, an extra length portion is secured in the sheet body, and after the sheet body securing the extra length portion is shaped into the cavity, The movable member protrudes, and a part (extra length portion) of the sheet body is inserted into the hole of the mounting seat of the built-in component, and then the movable member is retracted and inserted by pressing with the pressure member from the opposite side. It has been proposed to form a crimped portion by expanding the top of the sheet body (see, for example, Patent Document 1). In this way, if the extra length portion is formed in advance in the seat body, a local change in the thickness of the fuel tank can be suppressed even if a part of the seat body is inserted into the hole of the mounting seat. .

Japanese Patent Laying-Open No. 2015-85916

  However, when configured as described above, a drive mechanism and a heater for driving the movable member and the pressure member are required for the split mold and the core, respectively, which complicates the structure of the mold and reduces the cost. Has the disadvantage of becoming higher.

  The present invention has been made in consideration of the above facts, and an object of the present invention is to provide a method for manufacturing a resin fuel tank that does not require a complicated mechanism and suppresses a local change in the thickness of the fuel tank.

  The invention according to claim 1 is a method of manufacturing a resin fuel tank in which a built-in component is attached to the resin fuel tank, and a recess having an injection part for injecting an injection material at a built-in component attachment position on the bottom surface of the cavity of the split mold. A first step of forming a sheet body made of a molten resin in the cavity and the recess, and a mounting part for a built-in component having an undercut shape projectingly formed on the bottom after the first step A second step of arranging the injection material on the concave portion; and a third step of injecting an injection material from the injection portion to the sheet body arranged in the concave portion after the second step.

  According to this structure, the recessed part is formed in the built-in component attachment position of the bottom face of the cavity, and the injection part is formed in the recessed part. When the sheet body is shaped into the cavity, it is also shaped into the recess. The portion shaped in the concave portion of the sheet body becomes the extra length portion.

  The mounting part for the built-in component is arranged on the recessed portion of the sheet body shaped in this state. An undercut shape portion having an undercut shape is formed on the bottom surface side of the attachment portion.

  Here, the injection material is injected from the injection portion provided in the concave portion to the sheet body (extra length portion) shaped into the concave portion. By this injection material, the extra length portion of the sheet body is brought into close contact with the bottom surface of the attachment portion and is brought into close contact with the undercut shape portion. At this time, the extra length portion (molten resin) of the sheet body wraps around to the back side of the undercut shape portion formed on the bottom surface of the mounting portion, and is filled with the molten resin. As a result, both surfaces of the undercut shape portion are sandwiched by the molten resin, and the attachment portion (built-in component) is fixed to the resin fuel tank.

  As described above, in the manufacturing method of the present invention, when the sheet body is shaped, the sheet body is provided with an extra length portion, and the injection material is injected into the extra length portion of the sheet body, thereby forming an undercut formed in the built-in component. Since the built-in component is attached with the extra length portion of the sheet body in close contact with the shape portion (filled with molten resin), it is possible to suppress a local change in the thickness of the fuel tank.

  In addition, in order to bring the sheet body into close contact with the mounting part of the built-in component, it is only necessary to inject the injection material from the injection part, so there is no need to provide an insert driven by an actuator in the split mold or core. The configuration is simplified.

  Since the manufacturing method of the resin fuel tank according to the first aspect of the present invention has the above-described configuration, a local change in the thickness of the fuel tank can be suppressed without requiring a complicated mechanism.

It is a longitudinal section showing a resin fuel tank concerning one embodiment of the present invention. It is a principal part perspective sectional view showing the caulking part of the resin fuel tank concerning one embodiment of the present invention. It is a principal part longitudinal cross-sectional view of the attachment mechanism which concerns on one Embodiment of this invention, and is a figure which shows the state before a sheet | seat body shaping. It is a principal part longitudinal cross-sectional view of the attachment mechanism which concerns on one Embodiment of this invention, and is a figure which shows a sheet | seat body shaping state. It is a principal part longitudinal cross-sectional view of the attachment mechanism which concerns on one Embodiment of this invention, and is a figure which shows the set state of a built-in component. It is a principal part longitudinal cross-sectional view of the attachment mechanism which concerns on one Embodiment of this invention, and is a figure which shows the injection state of injection resin. It is a longitudinal section showing a caulking part of a resin fuel tank concerning one embodiment of the present invention. It is a longitudinal cross-sectional view which shows the injection resin removal state of the crimping part of the resin fuel tank which concerns on the other example of this invention. It is a longitudinal cross-sectional view which shows the fusion | melting state of the molten resin and injection resin of the crimping part of the resin fuel tank which concerns on the other example of this invention. It is a longitudinal cross-sectional view which shows the crimping | crimped part of the resin fuel tank formed with the injection material different from the molten resin and molten resin which concerns on the other example of this invention.

  A method for manufacturing a resin fuel tank according to an embodiment of the present invention will be described with reference to FIGS. In addition, each figure is typical and the illustration with a low relevance to the present invention is omitted.

  First, the structure of the resin fuel tank 10 (hereinafter referred to as “fuel tank 10”) according to the present embodiment will be briefly described, and then the manufacturing apparatus 40 will be described.

  As shown in FIGS. 1 and 2, the fuel tank 10 includes a bottom surface 12, a side surface 14 extending upward from an end portion of the bottom surface 12, and an upper surface 16 extending in the width direction from the upper end of the side surface 14. ing. For example, a built-in component 18 is fixed to the bottom surface 12 inside the fuel tank 10. The built-in component 18 includes a built-in component main body 20, a mounting seat 22 fixed to the bottom surface 12, and a connecting member 24 that connects the mounting seat 22 and the built-in component main body 20. As shown in FIGS. 2 and 7, the mounting seat 22 includes a disk-shaped mounting seat main body 26 and an undercut shape portion 28 that protrudes downward from the center of the lower surface (bottom surface) of the mounting seat main body 26. ing. The undercut shape portion 28 includes a columnar neck portion 30 that protrudes downward from the center of the lower surface of the mounting seat body 26, and a disk having a smaller diameter than the mounting seat body 26 that protrudes radially from the lower end of the neck portion 30. And a brim-shaped brim portion 32. The mounting seat body 26 has a hole 34 that penetrates the upper surface and the lower surface at a position around the neck 30. Further, a flange portion 36 is formed on the outer peripheral portion of the mounting seat body 26. The flange portion 36 is thinner than the center side (in the radial direction).

  A portion where the undercut shape portion 28 is inserted (locked) inside the resin body constituting the bottom surface 12 is referred to as a caulking portion 38. The built-in component 18 is formed of a material having a melting point higher than that of the molten resin so as not to be fused to a sheet body 100 (molten resin) described later.

  Next, the manufacturing apparatus 40 will be described. As shown in FIG. 3, the manufacturing apparatus 40 includes a plurality of split molds 42 (only a part of one split mold is shown), and the split mold 42 has a cavity (concave part) 44. Is formed. At the mounting position of the built-in component 18 (mounting seat 22) on the bottom surface 44 </ b> A of the cavity 44, a circular recess 46 is formed that is one step lower than the bottom surface 44 </ b> A. The recess 46 includes a first taper surface 48 on the outermost diameter side, a second taper surface 50 having a larger inclination than the first taper surface 48 on the inner peripheral side of the first taper surface 48, and an inner portion of the second taper surface 50. A first bottom surface 52 that is parallel to the bottom surface 44 </ b> A on the circumferential side, and a second bottom surface 54 that is one step below the first bottom surface 52 at the center of the first bottom surface 52 are provided.

  In the split mold 42, an injection unit 56 corresponding to the injection part of the present invention is disposed below the recess 46. The injection unit 56 is installed in a hole 58 formed below the recess 46 of the split mold 42. Note that the diameter of the front end side of the hole 58 is reduced, and the hole 60 communicates with the recess 46 (second bottom surface 54).

  The injection unit 56 includes a cylinder 62 that is filled with an injection resin 64 and a rod 66 that controls the injection amount of the injection resin 64 from the cylinder 62. The cylinder 62 is formed with an injection portion 68 having a reduced diameter on the distal end side, and the injection portion 68 has a hole portion 70 for resin injection. When the rod 66 advances and retreats in the cylinder 62, the hole portion 70 is closed or opened, and when the hole portion 70 is opened, the injection resin 64 is injected from the cylinder 62.

  A vacuum passage 72 that supplies a negative pressure to shape the sheet body 100 is formed in the bottom surface 44 </ b> A and the recess 46 of the cavity 44.

  A mounting mechanism 74 for the built-in component 18 is configured by the recess 46, the injection unit 56, and the vacuum passage 72 thus configured.

Then, the manufacturing method of the resin fuel tank using the metal mold | die comprised in this way is demonstrated.
As shown in FIG. 3, in the injection unit 56, the rod 66 closes the hole 70 in the initial state.

  Next, as shown in FIG. 4, the sheet body 100 made of the molten resin supplied to the split mold 42 by supplying a negative pressure from the vacuum passage 72 to the cavity 44 and the concave portion 46, the bottom surface 44 </ b> A of the cavity 44, etc. Close contact (vacuum shaping). At this time, as shown in FIG. 4, the sheet body 100 is formed along the recess 46 (first tapered surface 48, second tapered surface 50, first bottom surface 52, second bottom surface 54) formed in the bottom surface 44 </ b> A of the cavity 44. Closely contact (vacuum shaping). That is, the extra length portion 102 for forming the crimping portion 38 of the fuel tank 10 is formed on the sheet body 100.

  Subsequently, the built-in component 18 is installed at a predetermined position of the sheet body 100 formed on the bottom surface 44 </ b> A of the cavity 44. At this time, as shown in FIG. 5, the mounting seat 22 of the built-in component 18 is installed on the recess 46 (on the sheet body 100). In addition, since the flange part 36 whose plate | board thickness is thinner than the center side is formed in the outer peripheral part of the mounting seat main body 26, it adheres on the 1st taper surface 48 of the recessed part 46, and on the sheet body 100 inclined. It becomes easy to arrange the flange portion 36. That is, the mounting seat 22 can be easily positioned.

  In addition, an undercut portion 28 protrudes from the lower surface of the mounting seat body 26, but the sheet body 100 in close contact with the recess 46 is recessed downward from the bottom surface 44A of the cavity 44 (bottom surface 44A). Therefore, the undercut shape portion 28 does not interfere with the sheet body 100.

  After the installation of the built-in component 18 is completed in this way, the rod 66 of the injection unit 56 is driven and retracted (lowered) from the hole 70 as shown in FIG. As a result, the injection resin 64 in the cylinder 62 is injected from the injection portion 68 to the mounting seat 22 side. As a result, the sheet body 100 (extra length portion 102) that is in close contact with the recess 46 is pressed against the lower surface of the mounting seat body 26 by being pressed by the injection resin 64. As a result, the sheet body 100 is brought into intimate contact with the lower surface of the mounting seat main body 26 and is in intimate contact with the undercut shape portion 28 that is formed to protrude from the lower surface. At this time, the molten resin (sheet body 100) wraps around to the back side of the brim portion 32 constituting the undercut shape portion 28 and fills the periphery of the neck portion 30.

  In this case, even if the undercut shape portion 28 is filled with the molten resin up to the periphery of the neck portion 30, the surplus length portion 102 (molten resin) formed in the sheet body 100 is used, so the fuel tank 10 (crimped portion 38). It is prevented or suppressed that the plate | board thickness changes locally.

  In addition, since the hole part 34 penetrated up and down is formed around the neck part 30 of the mounting seat body 26, when the molten resin is finally filled around the neck part 30, the hole part 34 is connected to the upper surface side. Air is discharged. Therefore, the molten resin can be reliably filled around the neck portion 30 without a gap.

  With the built-in component 18 attached to the sheet body 100 in this manner, the split mold 42 is closed, and the shaped sheet bodies are joined together to form the fuel tank 10. Further, as shown in FIG. 7, the built-in component 18 is filled with molten resin on the upper side and the lower side of the undercut shape portion 28 (head portion 32) formed in the lower portion of the mounting seat body 26. Since the molten resin is solidified in the sandwiched state and the crimping portion 38 is formed, the built-in component 18 can be easily fixed to the fuel tank 10.

  In addition, the undercut shape portion is not formed by deforming the sheet body 100, but the undercut shape portion 28 is formed in the built-in component 18 (mounting seat 22), and the excess length of the sheet body 100 is formed in the undercut shape portion 28. Since the caulking portion 38 is formed by filling the molten resin in the portion 102, the thickness of the fuel tank 10 can be prevented or suppressed from greatly changing locally.

  In particular, when the sheet body 100 is shaped into the cavity 44, the extra length portion 102 can be easily formed in the sheet body 100 because the concave portion 46 formed on the bottom surface 44 </ b> A of the cavity 44 is shaped.

  Furthermore, since the outer diameter of the mounting seat body 26 is sized corresponding to the inner diameter of the recess 46, the lower surface of the mounting seat body 26 can sufficiently receive the injection pressure of the injection resin 64, and the mounting seat body. 26, the outer peripheral portion (flange portion 36) contacts and seals the sheet body 100 on the first taper surface 48, so that the injection resin 64 passes between the mounting seat main body 26 and the recess 46 to form the cavity 44 (general surface). ) Side and the shape (design surface) of the sheet body 100 is prevented from collapsing.

  Further, since the attachment mechanism 53 for forming the crimping portion 38 is only configured to provide the injection unit 56 in the concave portion 46 formed on the bottom surface 44A of the cavity 44, the crimping portion 38 is formed in the core between the divided molds. There is no need to provide a nesting or the like, and the apparatus configuration is simplified.

  In addition, as shown in FIG. 8, the injection resin 64 can be removed from the crimping part 38 after shaping | molding by using resin which the injection resin 64 is incompatible with molten resin (sheet body 100).

  Further, as shown in FIG. 9, by using the same material as the molten resin (sheet body 100), the injection resin 64 can be fused and integrated with the sheet body 100 entirely. In this case, the caulking portion 38 can be reinforced.

  Furthermore, as shown in FIG. 10, compared with the present embodiment, by increasing the length of the neck portion 30 and the size of the flange portion 32 of the undercut shape portion 28, not only the molten resin (sheet body 100) The injection resin 64 can also go around to the back side of the flange portion 32. In this way, not only the molten resin but also the injection resin 64 can sandwich the flange portion 32, so that the rigidity of the caulking portion 38 of the fuel tank 10 is further improved.

  If a material different from the resin is injected instead of the injection resin 64, the injection material is not joined to the molten resin (sheet body 100), so that when the external force acts on the fuel tank 10 (caulking portion 38), the injection material Thus, the load transmitted to the wall portion of the fuel tank 10 can be reduced. For example, when rubber is used as the injection material, the rubber absorbs most of the impact applied from the outside, and the impact transmitted to the wall portion of the fuel tank 10 can be greatly reduced.

  In the present embodiment, the mounting seat body 26 is formed in a circular shape, but the present invention is not limited to this. However, in terms of the extensibility of the sheet body 100 (molten resin), it is preferable that the mounting seat main body 26 has a disk shape.

  In the present embodiment, the undercut shape portion 28 is provided on the mounting seat 22, but an undercut shape portion may be provided on the bottom surface of the built-in component main body 20.

10 Resin fuel tank 18 Built-in component 22 Mounting seat (mounting part)
28 Undercut shape part 42 Split mold 44 Cavity 44A Bottom face 46 Concave part 56 Injection unit (injection part)
100 sheet body

Claims (1)

A method of manufacturing a resin fuel tank in which a built-in component is attached to the resin fuel tank,
A first step of forming a recess comprising an injection part for injecting an injection material at a built-in component mounting position on the bottom surface of the cavity of the split mold, and shaping a sheet body made of a molten resin in the cavity and the recess;
After the first step, a second step of disposing the mounting part of the built-in component on which the undercut shape part protrudes on the bottom surface on the recess,
After the second step, a third step of injecting an injection material from the injection part to the sheet body arranged in the recess;
A method for manufacturing a resin fuel tank comprising:

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