JP2015089771A - Fuel tank for automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel tank capable of attaching a built-in component to a prescribed position in the fuel tank such that the built-in component is not deviated with respect to parison upon blow molding.SOLUTION: A fuel tank 1 for automobile is formed according to blow molding, allows a built-in component 20 to be attached to an internal part and has an external wall 10 formed with synthetic resin. Therein, a plurality of attachment members 30 for attaching the built-in component 20 are provided so as to be fused on an inner surface of the external wall 10 of the fuel tank 1 on the built-in component 10. Each of the attachment members 30 is provided with a contact part 32 which comes into contact with the inner surface of the external wall 10 of the fuel tank 1 and the contact part 32 has a contact surface 33 opposite to the inner surface of the external wall 10 of the fuel tank 1. The inner surface of the external wall 10 of the fuel tank 1 to which the contact surface 33 is fused forms an external wall inner surface protrusion part 18 which is extended in the inner part direction of the fuel tank 1 so as to surround the circumference of the contact surface 33.

Description

The present invention relates to a fuel tank made of thermoplastic synthetic resin, and more particularly to a fuel tank in which an outer wall is formed by blow molding a thermoplastic synthetic resin member and has a built-in component inside.

Conventionally, the structure of fuel tanks for automobiles and the like has been made of metal, but in recent years, thermoplasticity has been achieved by reducing the weight of the vehicle, eliminating rust, and easily forming into a desired shape. Those made of synthetic resin have come to be used.
In the production of an automotive fuel tank made of a thermoplastic synthetic resin, a blow molding method has been often used because of the ease of molding a hollow body. In the blow molding method, a parison of a molten thermoplastic synthetic resin member is formed into a cylindrical shape and extruded from above, and the parison is sandwiched between molds and air is blown into the parison to manufacture an automobile fuel tank.

On the other hand, also in the blow molding method, it is required to provide internal components such as valves and a baffle plate for suppressing fuel flow noise inside the fuel tank.
Therefore, the built-in parts are set on the resin frame, the resin frame is set in the mold, blow molded, and the resin frame is fixed to the inner peripheral surface of the outer wall of the fuel tank, and the built-in parts are placed inside the fuel tank. Some are attached (see, for example, Patent Document 1).

However, in this case, since the built-in parts are set on the resin frame and fixed to the inner peripheral surface of the outer wall of the fuel tank, it is necessary to remove the resin frame after molding. The weight may increase.

Moreover, in order to provide a built-in component inside a fuel tank, it may carry out as shown in FIGS. 12-13 (for example, refer patent document 2).
First, as shown in FIG. 12, before the parison 108 enters the blow molding die 140, the built-in component 120 is placed on the support bar 141, and the blow molding die 140 is opened and positioned therein. Thereafter, the parison 108 is lowered while the blow molding die 140 is kept open so that the built-in component 120 is positioned inside the parison 108.

Thereafter, as shown in FIG. 13, before closing the blow molding die 140, the pressing pins 142 are taken out from both sides of the blow molding die 140, the parison 108 is pressed, and the parison 108 is placed on the side end of the built-in component 120. Press. At this time, since the inner surface of the parison 108 is not yet solidified, the side ends of the parison 108 and the built-in component 120 can be fused.
Then, the support bar 141 is lowered, the blow molding die 140 is closed, and air is blown to perform blow molding.

In this case, the contact surface 133 that contacts the parison 108 formed at the tip of the built-in component 120 and the inner surface of the parison 108 are merely in contact, and the contact surface 133 does not enter the interior of the parison 108 and adhesion However, the fusion strength is not sufficiently high, and there is a risk of peeling due to vibration of the fuel or expansion of the fuel tank.

For this reason, as shown in FIG. 14, a configuration in which a plurality of cylindrical contact pins 234 are formed on the contact surface 233 of the mounting member 230 of the built-in component is considered (see, for example, Patent Document 3).
At this time, at the time of blow molding, the pressing pin 242 of the blow molding die 240 presses the parison 208, and the parison 208 presses the contact pin 234 formed on the contact surface 233 of the mounting member 230. The top portion 235 of the 234 enters the inside from the surface of the parison 208, the top portion 235 is melted, and the parison 208 and the mounting member 230 are welded.

At this time, however, the mounting member 230 acts to press the parison 208 with the mounting member 230 and the pressing pin 242 of the blow molding die 240 as indicated by the white arrow in FIG. Since the surface 242a is planar, the parison 208 flows in the outward direction of the attachment member 230 along the push pin pressing surface 242a as indicated by the black arrow in FIG.
For this reason, there is a problem that the mounting member 230 is displaced with respect to the parison 208, the mounting position of the mounting member 30 is moved, and the built-in components are displaced.

JP-A-1-301227 JP-A-6-143396 JP 2009-132297 A

  Therefore, an object of the present invention is to provide a fuel tank in which a built-in component does not shift with respect to the parison during blow molding, and the built-in component can be attached at a predetermined position in the fuel tank.

The present invention of claim 1 for solving the above-mentioned problem is a fuel tank for automobiles, which is formed by blow molding, has a built-in component inside, and has an outer wall formed of synthetic resin.
The built-in component is provided with a plurality of mounting members for attaching the built-in component by fusing to the inner surface of the outer wall of the fuel tank, and the mounting member is formed with a contact portion that contacts the inner surface of the outer wall of the fuel tank. Has a contact surface facing the inner surface of the outer wall of the fuel tank,
The fuel tank for an automobile is characterized in that the inner surface of the outer wall of the fuel tank to which the contact surface is fused is formed with an outer wall inner surface protrusion projecting inward of the fuel tank so as to surround the periphery of the contact surface. .

In the first aspect of the present invention, the built-in component is provided with a plurality of attachment members for attaching the built-in component by fusing to the inner surface of the outer wall of the fuel tank. It can be fused and fixed to, and can be attached stably.
Since the attachment member is formed with a contact portion that contacts the inner surface of the outer wall of the fuel tank, the contact portion can be fused to the inner surface of the outer wall of the fuel tank, and the attachment member can be fixed.

The attachment member is formed with a contact portion that contacts the inner surface of the outer wall of the fuel tank, and the contact portion has a contact surface that faces the inner surface of the outer wall of the fuel tank. For this reason, the contact surface of the attachment member and the inner surface of the outer wall of the fuel tank, which is a melted parison, are fused, and the attachment member can be firmly fixed to the outer wall of the fuel tank.

The inner surface of the outer wall of the fuel tank to which the contact surface is fused formed an outer wall inner surface protrusion projecting inward of the fuel tank so as to surround the periphery of the contact surface. For this reason, when the contact surface of the mounting member is pressed against the parison and fused, the press pin pressing protrusion of the blow molding die that forms the outer wall inner surface protrusion surrounds the contact surface in a ring shape. Thus, the flow of the parison can be prevented, the attachment member is not displaced, and the attachment member can be attached to a predetermined position on the inner surface of the outer wall of the fuel tank.

According to the second aspect of the present invention, the inner surface of the portion where the abutment surface of the outer wall of the fuel tank is fused is planar, and the outer wall inner surface protrusion is formed by surrounding the abutment surface in a ring shape. It is a fuel tank.

In the present invention of claim 2, the inner surface of the portion where the contact surface of the outer wall of the fuel tank is fused is flat, and the outer wall inner surface protrusion is formed so as to surround the contact surface in a ring shape. For this reason, when the abutting surface of the mounting member is pressed against the parison and fused, the pressing pin pressing projection of the blow molding die that forms the outer wall inner surface projection formed by surrounding the abutting surface in a ring shape The part surrounds the periphery of the contact surface in a ring shape to prevent the parison from flowing, the attachment member is not displaced, and the attachment member can be attached to a predetermined position on the inner surface of the outer wall of the fuel tank.

According to the third aspect of the present invention, the inner surface of the outer wall of the fuel tank to which the contact surface is fused is a surface that is curved in a spherical shape so as to protrude outwardly of the fuel tank, and the outer wall inner surface protrusion has the contact surface. This is a fuel tank for automobiles in which the tip of a spherically curved surface that covers the contact surface is formed in a ring shape.

According to the third aspect of the present invention, the inner surface of the outer wall of the fuel tank to which the contact surface is fused is a surface that is curved in a spherical shape so as to protrude outwardly of the fuel tank, and the outer wall inner surface protrusion has the contact surface The tip of the spherically curved surface to cover the contact surface was formed in a ring shape. For this reason, when the abutting surface of the mounting member is pressed against the parison and fused, the outer surface of the outer wall is formed such that the tip of the spherically curved surface covering the abutting surface surrounds the abutting surface in a ring shape The pressing pin pressing protrusion of the blow mold that forms the protrusion surrounds the periphery of the contact surface in a ring shape to prevent the parison from flowing, and the mounting member is not displaced, and the mounting member is fueled. It can be attached to a predetermined position on the inner surface of the outer wall of the tank.

According to a fourth aspect of the present invention, the contact portion is a fuel tank for an automobile in which a plurality of contact pins project from the contact surface toward the inner surface of the outer wall of the fuel tank.

According to the fourth aspect of the present invention, the contact portion is formed such that a plurality of contact pins protrude from the contact surface toward the inner surface of the outer wall of the fuel tank. For this reason, a plurality of contact pins can enter the inside of the outer wall of the fuel tank and be fused to firmly fix the attachment member to the outer wall of the fuel tank.

According to a fifth aspect of the present invention, there is provided a fuel tank for an automobile in which the contact pin is welded to the inner surface side of the outer wall of the fuel tank.

In the present invention of claim 5, since the contact pin is welded to the inner surface side of the outer wall of the fuel tank, the length of the contact pin entering the inside of the outer wall of the fuel tank during blow molding is long. The amount of fusion increases, and the attachment member can be firmly fixed to the outer wall of the fuel tank.

The mounting member has a contact portion that contacts the inner surface of the outer wall of the fuel tank, and the contact portion has a contact surface that faces the inner surface of the outer wall of the fuel tank. Then, the inner surface of the outer wall of the fuel tank, which is a melted parison, is fused, and the mounting member can be firmly fixed to the outer wall of the fuel tank.
The inner surface of the outer wall of the fuel tank, where the contact surface is fused, is formed with an outer wall inner surface protrusion that protrudes toward the inside of the fuel tank so as to surround the periphery of the contact surface, so that the outer wall inner surface protrusion prevents the flow of the parison. The mounting member can be mounted at a predetermined position on the inner surface of the outer wall of the fuel tank.

It is a fuel tank perspective view which is an embodiment of the invention. It is a partial expanded sectional view which shows the structure of the outer wall of the fuel tank of this invention. It is a perspective view of the built-in components attached to the inside of the fuel tank of the present invention. It is a top view of the attachment member of the 1st Embodiment of this invention. It is sectional drawing of the attachment member of the 1st Embodiment of this invention, and is sectional drawing along the AA line of FIG. It is a bottom view of the attachment member of the 1st Embodiment of this invention. It is sectional drawing at the time of welding of the attachment surface of the attachment member of the 1st Embodiment of this invention, and a parison. It is sectional drawing at the time of the welding of the attachment surface of the attachment member of the 2nd Embodiment of this invention, and a parison. It is sectional drawing of the state which opened the blow molding die which shows the fuel tank manufacturing method of this invention. It is sectional drawing of the state which slid the press pin of the blow molding die which shows the fuel tank manufacturing method of this invention. It is sectional drawing of the state which closed the blow molding die which shows the fuel tank manufacturing method of this invention. It is sectional drawing of the state which closed the blow molding die which shows the conventional fuel tank manufacturing method. It is sectional drawing of the state which slid the press pin of the blow molding die which shows the conventional fuel tank manufacturing method. It is a top view of the conventional attachment member. It is sectional drawing of the process which attached the conventional attachment member to the parison.

An automotive fuel tank 1 according to an embodiment of the present invention will be described with reference to FIGS.
In the embodiment of the present invention, as shown in FIG. 1, the fuel tank 1 has a pump unit mounting hole 4 formed on the upper surface so that a fuel pump (not shown) and the like can be taken in and out of the fuel tank 1. . A fuel injection hole 5 for injecting fuel from an inlet pipe (not shown) is formed on the side surface or the upper surface of the fuel tank 1.

An outer peripheral rib 2 is formed around the entire circumference of the fuel tank 1, and mounting holes 3 are formed at predetermined locations such as corner portions of the outer peripheral rib 2. The fuel tank 1 is attached to the vehicle body by bolting 3 and the vehicle body. It is also possible to attach a belt to the outer periphery of the fuel tank 1 instead of the attachment hole 3 and attach the fuel tank 1 to the vehicle body by the belt.
Furthermore, on the upper surface of the fuel tank 1, there are formed attachment holes 6 at various places for connecting a hose or the like for collecting the internal fuel vapor.

In the present embodiment, the fuel tank 1 is formed by blow molding, and its outer wall 10 has an outer skin layer 11, an outer body layer 12, an outer adhesive layer 13, and a barrier layer 14 in order from the outer side as shown in FIG. The inner adhesive layer 15 and the inner main body layer 16 are formed.
In blow molding, a parison composed of the above six layers is used. A parison having a layer structure of six layers or more can also be used. In addition, the skin layer 11 is used when a reproducing member, a filler, or the like is mixed in the external main body layer 12, but the skin layer 11 can be omitted. Further, if a material having rigidity and fuel oil resistance is used, a one-layer parison can be used.

The skin layer 11 and the outer main body layer 12 are formed of a thermoplastic synthetic resin that has high impact resistance and maintains rigidity against fuel oil, and is preferably formed of high-density polyethylene (HDPE). When the outer main body layer 12 contains an inorganic filler, the outer skin layer 11 is used to cover the surface of the outer main body layer 12, and the surface can be smoothed without any inorganic filler appearing on the surface. .

For example, a built-in component 20 shown in FIG. 3 is attached inside the fuel tank 1. A method for attaching the built-in component 20 will be described later.
Next, the built-in component 20 will be described with reference to FIG.
The built-in component 20 is provided with a plurality of attachment members 30 that are fused to the inner surface of the outer wall of the fuel tank 1 to support the upper and lower sides. The attachment member 30 will be described later.

A contact surface 33 is attached to a tip portion of the attachment member 30 that contacts the inner surface of the outer wall 10 of the fuel tank 1. In the present embodiment, the contact surface 33 is formed integrally with the attachment member 30, but may be formed separately from the attachment member 30 at the tip of the attachment member 30.
The contact surface 33 attached to the upper surface 21 of the built-in component 20 is welded to the inner surface of the parison 8 that forms the upper side wall of the outer wall 10 of the fuel tank 1 during blow molding, so that the built-in component 20 is placed inside the fuel tank 1. Can be installed. Further, the contact surface 33 of the mounting member 30 formed downward in the upper surface hole 24 of the built-in component 20 is welded to the bottom wall side of the outer wall 10.

The built-in component 20 can be formed of a fuel oil-resistant thermoplastic synthetic resin such as polyacetal or high-density polyethylene (HDPE). As a result, the strength of the fuel tank 1 can be improved, and even if the fuel tank 1 is attached to the inside of the fuel tank 1, the rigidity does not decrease due to swelling by the fuel oil or the like.

As shown in FIG. 3, the built-in component 20 of the present embodiment is formed in a ring shape having a space in the center and a continuous periphery in a substantially square shape. In addition, in this invention, the built-in component 20 which connected the column member with the beam member other than the form shown in FIG. 3 can also be used.

The ring-shaped portion of the built-in component 20 according to the present embodiment includes an upper surface 21 whose upper surface is formed on a substantially flat surface, an outer surface 22 that hangs from the upper surface 21 at a substantially right angle to the outer periphery, and a center from the upper surface 21. The inner surface 23 is formed in a shape formed of an inner surface 23 that hangs substantially perpendicular to the space side of the portion, and the interior surrounded by the upper surface 21, the outer surface 22, and the inner surface 23 is a hollow shape that does not have a lower side surface having a U-shaped cross section. Is formed. For this reason, the built-in component 20 can reduce the weight as a whole, contribute to weight reduction of the vehicle, and can be flexibly deformed. The upper surface 21, the outer surface 22, and the inner surface 23 are partially formed with a narrow width at the corner portion or short side of the fuel tank 1.

A plurality of mounting members 30 described above are formed on the upper surface 21, and a plurality of recessed upper surface hole portions 24 are formed. An attachment member 30 and a contact surface 33 can be formed on the bottom of the upper surface hole 24. As described above, the abutment surface 33 can be fused with the lower inner surface of the outer wall 10 to attach the built-in component 20 to the inside of the fuel tank 1. Thereby, even if the outer wall 10 of the fuel tank 1 expands or contracts due to a change in the internal pressure of the fuel tank 1, the outer wall 10 of the fuel tank 1 can be held.

The outer side surface 22 and the inner side surface 23 are formed long in the longitudinal direction on the long side of the built-in component 20. For this reason, the outer side surface 22 and the inner side surface 23 are formed in a direction orthogonal to the direction of fuel movement in the fuel tank 1 when the vehicle is running. Even if the fuel moves or undulates, it is possible to prevent excessive movement of the fuel and to prevent the generation of undulation noise of the fuel oil inside the fuel tank 1 as well as the generation of abnormal noise. it can.

The built-in component 20 is provided with a plurality of mounting members 30 to be described later for attaching the built-in component 20 by fusing to the inner surface of the outer wall 10 of the fuel tank 1. For this reason, the built-in component 20 can be fused and fixed to the inner surface of the outer wall 10 of the fuel tank 1 at a plurality of locations, and can be stably attached.

Next, the attachment member 30 will be described with reference to FIGS.
The attachment member 30 may be formed integrally with the built-in component 20 or may be formed separately from the built-in component 20. In the present embodiment, an example in which the attachment member 30 is formed separately will be described.
As shown in FIGS. 3 to 6, the attachment member 30 may be formed in a cylindrical or rectangular tube shape, or may be formed in a flat plate shape.
In the present embodiment, the mounting member 30 is formed in a cylindrical tube shape, FIG. 4 is a plan view of the mounting member 30, FIG. 5 is a cross-sectional view of the mounting member 30, and FIG. 6 is a bottom view of the mounting member 30. It is.

The attachment member 30 is formed of an attachment member side wall 31 connected or continuous with the built-in component 20 and an abutment portion 32 that abuts against the inner surface of the outer wall 10 of the fuel tank 1.
In the present embodiment, the attachment member 30 is formed separately from the built-in component 20. In this case, the attachment member side wall 31 is formed in a cylindrical shape in accordance with the shape of the upper surface 21 of the built-in component 20, and the inside is hollow. A locking portion 38 is formed at the lower end of the mounting member side wall 31, and when the mounting member side wall 31 is fitted into the tip of the upper surface 21 of the built-in component 20, as shown in FIGS. The attachment members 30 are firmly attached by engaging the 38 claws with the recesses or holes formed at the tip of the upper surface 21. The attachment member 30 uses the same type of material as the material of the outer wall 10 in order to fuse with the outer wall 10 of the fuel tank 1.

When the attachment member 30 is formed integrally with the built-in component 20, the attachment member side wall 31 is formed continuously with the upper surface 21.
The contact portion 32 is formed with a circular contact surface 33 facing the inner surface of the outer wall 10 of the fuel tank 1 and a plurality of contact pins 34 protruding from the contact surface 33 toward the outer wall 10 of the fuel tank 1. ing. The contact pin 34 is formed in a columnar shape or a truncated cone shape having a circular or elliptical cross-sectional shape. In the present embodiment, the contact pin 34 is formed in a cylindrical shape. The contact pin 34 may be formed in a truncated cone shape, or may be formed in an elliptic cylinder shape or a truncated cone shape having an elliptical cross section.

Furthermore, the height of the contact pin 34 from the contact surface 33 is formed smaller than the thickness of the outer wall 10 of the fuel tank 1. For this reason, the contact surface 33 can be brought into close contact with the inner surface of the outer wall 10 of the fuel tank 1 so that the maximum value of the size of the contact pin 34 entering the outer wall 10 of the fuel tank 1 can be controlled. The contact pin 34 penetrates into the outer wall 10 of the fuel tank 1 and can be firmly bonded to the outer wall 10 of the fuel tank 1. A contact pin groove portion 36 can be provided around the contact pin 34. Thereby, the flexibility of the contact pin 34 is improved.

For this reason, when the contact surface 33 is pressed against the outer wall 10 of the fuel tank 1, the contact pin 34 can sufficiently enter the inside of the outer wall 10 of the fuel tank 1. The top portion 35 of the contact pin 34 can be fused with the outer wall 10 of the fuel tank 1 in contact with the melted portion inside. Therefore, the outer wall 10 of the fuel tank 1 and the contact portion 32 can be firmly fused.

It is preferable that the contact pin 34 penetrates and is welded to the inner surface side of the outer wall 10 of the fuel tank 1 by about 1/2 to 2/3 of the thickness of the outer wall 10. In this case, the length that the contact pin 34 enters the inside of the outer wall 10 of the fuel tank 1 at the time of blow molding is long, the amount of fusion of the contact pin 34 increases, and the mounting member 30 is firmly attached to the fuel tank 1. The outer wall 10 can be fixed.

In the present embodiment, the distance between the contact pin 34 and the adjacent contact pin 34 is 1 to 3 mm. Therefore, when the attachment member 30 is fused to the outer wall 10 of the fuel tank 1, the inner surface of the melted outer wall 10 can enter between the contact pin 34 and the contact pin 34, and the contact pin 34. Has a space that can sufficiently enter the inside of the outer wall 10 of the fuel tank 1. Furthermore, since the distance between the adjacent contact pins 34 is not too wide, the number of contact pins 34 can be increased, and the fusion strength with the outer wall 10 of the fuel tank 1 can be ensured.

In this case, when the contact portion 32 is pressed against the inner surface of the outer wall 10 of the fuel tank 1, the contact pin 34 enters the outer wall 10 of the fuel tank 1, which is the parison 8, and the contact pin 34 and the contact pin 34 are in contact with each other. The outer wall 10 of the fuel tank 1 melted in between can enter, and the outer wall 10 of the fuel tank 1 and the contact surface 33 can be firmly fixed.

In the present embodiment, as shown in FIG. 4, the contact pin 34 is formed on substantially the entire surface of the contact surface 33. Therefore, a large number of contact pins 34 can be formed on the contact surface 33, the outer wall 10 of the fuel tank 1 can be fused to the entire surface of the contact surface 33, and the outer wall 10 of the fuel tank 1 can be fused. It is possible to ensure the fusion strength.

Further, the contact pin 34 can be formed in a truncated cone shape from the contact surface 33. In this case, since the cross-sectional area of the top portion of the contact pin 34 is small, when the outer wall 10 of the fuel tank 1 and the contact pin 34 are fused, the apex of the contact pin 34 is located inside the outer wall 10. When invading, the melted outer wall 10 easily enters between the contact pins 34 and the contact pins 34, and the outer wall 10 and the contact pins 34 are easily adapted to be firmly fused. Further, since the contact pin 34 has a truncated cone shape, when it enters the outer wall 10, the molten resin between the contact pin 34 and the contact pin 34 is obstructed, and the contact pin 34 greatly enters the outer wall 10. Can be prevented.

When the attachment member 30 is attached to the outer wall 10 of the fuel tank 1, the contact pin 34 of the attachment member 30 enters the inside of the outer wall 10, and the contact surface 33 slightly enters the inside of the outer wall 10.
As will be described later, the outer wall 10 is formed with an outer wall inner surface protrusion 18 projecting in the inner direction of the fuel tank 1 so as to surround the periphery of the contact surface 33 at a portion surrounding the periphery of the attachment member 30.

Since the outer wall inner surface protrusion 18 is formed, when the abutting surface 33 of the mounting member 30 is pressed against the parison 8 and fused, the outer wall inner surface protrusion 18 causes the parison 8 to flow as described later. Therefore, the attachment member 30 is not displaced, and the attachment member 30 can be attached to a predetermined position on the inner surface of the outer wall 10 of the fuel tank 1.

In the embodiment shown in FIG. 7, the outer wall inner surface fused portion 17 of the outer wall 10 at the portion where the abutment surface 33 is fused to the outer wall 10 of the fuel tank 1 is formed in a flat shape, and the outer wall inner surface protruding portion. 18 is formed surrounding the contact surface 33 in a ring shape. As will be described later, since the pressing pin pressing surface 42a of the pressing pin 42 of the blow molding die 40 is formed with a pressing pin pressing protrusion 42b so as to surround the contact surface 33, as will be described later, the parison. This is because 8 is pressed by the pressing pin pressing protrusion 42 b and the outer wall inner surface protrusion 18 is formed on the outer wall 10.

As shown in FIG. 7, the flow of the parison 8 is restricted during blow molding by the pressing pin pressing protrusion 42 b, and the parison 8 is pressed so as to surround the abutting surface 33 at the portion of the abutting surface 33. On the inner side of the pressing pin pressing protrusion 42b, the parison 8 presses the periphery of the contact surface 33 from all directions, so that the contacting portion 32 is not displaced. On the outer side of the pressing pin pressing protrusion 42b, the contact surface 33 is not moved. It flows away from. For this reason, the attachment member 30 does not move when the parison 8 is pressed, and can be reliably attached to a predetermined position.

Further, in the second embodiment shown in FIG. 8, the outer wall inner surface fusion portion 17 of the outer wall 10 at the portion where the contact surface 33 is fused to the outer wall 10 of the fuel tank 1 It is formed with a convexly curved surface. This is because the pressing pin pressing surface 42a of the pressing pin 42 of the blow molding die 40 is formed into a spherical shape as a concave surface during blow molding, and the portion around the pressing pin pressing surface 42a is the pressing pin pressing protrusion 42b. It is formed as.
For this reason, the outer wall inner surface protrusion 18 of the outer wall 10 is formed so as to surround the contact surface 33 in a ring shape.

As shown in FIG. 8, similarly to the case of FIG. 7, the flow of the parison 8 is restricted by the pressing pin pressing protrusion 42 b at the time of blow molding, and the contact surface 33 surrounds the contact surface 33. The parison 8 is pressed in such a manner that the parison 8 presses the periphery of the abutting surface from all directions inside the pressing pin pressing projection 42b, and is separated from the abutting surface 33 outside the pressing pin pressing projection 42b. To flow. For this reason, the attachment member 30 does not move when the parison 8 is pressed, and can be reliably attached to a predetermined position.

Next, a method for manufacturing the fuel tank 1 of the present invention by blow molding will be described with reference to FIGS.
First, as shown in FIG. 9, the built-in component 20 is held by the support bar 41 and is positioned inside the blow molding die 40. Thereafter, the parison 8 is lowered and the built-in component 20 is positioned inside the parison 8.

Then, as shown in FIG. 10, the first pinch plate 43 is slid to hold the lower end of the parison 8 together with the support bar 41. At the same time, the plurality of pressing pins 42 provided on the blow molding die 40 are slid to press the parison 8 so as to be sandwiched between the mounting member 30 attached to the built-in component 20 and the pressing pins 42.

Then, since the inner surface of the parison 8 is still in a molten state, the contact pin 34 of the contact portion 32 of the mounting member 30 enters the inner surface of the parison 8 as described above, and the contact portion 32 and the parison 8 are melted. Can be worn. At this time, since the built-in component 20 is held by the support rod 41, the attachment member 30 and the built-in component 20 can be reliably attached to a predetermined position on the outer wall 10 of the fuel tank 1.

At this time, as described above, since the pressing pin pressing projection 42b is formed on the pressing pin pressing surface 42a of the pressing pin 42, the parison 8 is pressed, and the outer wall 10 of the fuel tank 1 has an outer wall inner surface protruding portion. 18 is formed.

Thereafter, as shown in FIG. 11, the support bar 41 is lowered and removed from the blow molding die 40, the second pinch plate 44 is slid to close the parison 8, and the blow molding die 40 is closed to slide the cutter. At 46, the parison 8 is cut. When closing the blow molding die 40, the pressing pin 42 continues to press the parison 8 as it is. Thereby, the built-in component 20 can be kept in a predetermined position.

Then, air is blown into the inside of the parison 8 from the air nozzle 45, and the outer surface of the parison 8 is pressed against the blow molding die 40 to form the fuel tank 1. At this time, the front end surface of the pressing pin 42 and the cavity inner surface of the blow molding die 40 can be flush with each other.
Thereafter, the blow molding die 40 is opened and the fuel tank 1 is taken out.

DESCRIPTION OF SYMBOLS 1 Fuel tank 8 Parison 10 Outer wall 17 Outer wall inner surface fusion | fusion part 18 Outer wall inner surface protrusion 20 Built-in components 30 Mounting member 32 Contact part 33 Contact surface 34 Contact pin 40 Blow molding die

Claims (5)

In an automotive fuel tank that is formed by blow molding, has built-in components inside, and has an outer wall formed of synthetic resin,
The built-in component is provided with a plurality of mounting members that are fused to the inner surface of the outer wall of the fuel tank to mount the built-in component, and the mounting member is formed with a contact portion that contacts the inner surface of the outer wall of the fuel tank. And the contact portion has a contact surface facing the inner surface of the outer wall of the fuel tank,
The inner surface of the outer wall of the fuel tank to which the contact surface is fused is formed with an outer wall inner surface protrusion projecting inward of the fuel tank so as to surround the periphery of the contact surface. Fuel tank. 2. The inner surface of the portion where the contact surface of the outer wall of the fuel tank is fused is a flat surface, and the outer wall inner surface protrusion is formed to surround the contact surface in a ring shape. Automotive fuel tank. The inner surface of the outer wall of the fuel tank to which the contact surface is fused is a surface curved in a spherical shape that protrudes outwardly of the fuel tank, and the outer wall inner surface protrusion is a spherical surface that covers the contact surface. 2. The fuel tank for an automobile according to claim 1, wherein a tip of a curved surface is formed so as to surround the contact surface in a ring shape. 4. The contact portion according to claim 1, wherein a plurality of contact pins project from the contact surface toward the inner surface of the outer wall of the fuel tank. The fuel tank for automobiles described in 1. The automobile fuel tank according to claim 4, wherein the contact pin is welded to an inner surface side of an outer wall of the fuel tank.