JP2015058715A - Fuel tank for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel tank capable of protecting an outer wall of the fuel tank even if an integrated component is fused to an inner surface of the outer wall of the fuel tank and an impact etc. is applied to the outer wall of the fuel tank.SOLUTION: A fuel tank 1 for a vehicle is formed by blow molding and has an outer wall made of a synthetic resin. An integrated component 20 is attached to the interior of the fuel tank 1. In the integrated component 20, multiple attachment members 30 which are fused to an inner surface of the outer wall 10 of the fuel tank 1 to attach the integrated component 20 are provided. In the attachment member 30, a contact part 32 which contacts with the inner surface of the outer wall 10 of the fuel tank 1 is formed into a plate form. The contact part 32 includes: a contact surface 33 which is fused to the inner surface of the outer wall 10 of the fuel tank 1; and an inner surface 37 at the opposite side of the contact surface 33. A recessed part 39 is formed in the inner surface 37.

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).

In order to provide a built-in component inside the fuel tank, the built-in component may be held by a support rod and placed in the parison 8 as shown in FIG. 13 (see, for example, Patent Document 2).
First, 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, 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 pressed against the side end of the built-in component 120. 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.

Therefore, as shown in FIG. 14, a plurality of arc-shaped protrusions 135 having a triangular cross-sectional shape are formed on the contact surface 133 of the mounting member 130 of the built-in component, and are firmly fused to the outer wall 10 of the fuel tank 1. There are some (see, for example, Patent Document 3).
However, in this case, when an impact or the like is applied to the outer wall surface of the fuel tank 1, the stress concentrates on the strongly fused portion, and the outer wall 10 of the fuel tank 1 may be deformed.

As shown in FIG. 15, a plurality of columnar contact pins 235 are provided on the contact surface 233 of the mounting member 230 having the connecting portion 231 and the contact portion 232, and the contact pin 235 and the contact pin 235 are provided. A groove 236 is provided between the contact pins 235 and the outer wall of the fuel tank is firmly fused (for example, see Patent Document 4). Even in this case, although the impact can be absorbed by the groove 236, the depth of the groove 236 is limited from the viewpoint of the moldability of the mounting member 230, and stress concentrates in the groove 236, and the fuel tank The outer wall 10 of 1 may be deformed.

JP-A-1-301227 JP-A-6-143396 JP 2009-132297 A JP2013-60096A

  Therefore, an object of the present invention is to provide a fuel tank capable of protecting the outer wall of the fuel tank even if the built-in component is fused to the inner surface of the outer wall of the fuel tank and an impact or the like is applied to the outer wall of the fuel tank. And

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 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 has a plate-like contact portion that contacts the inner surface of the outer wall of the fuel tank, The abutting portion has an abutting surface fused to the inner surface of the outer wall of the fuel tank and an inner side surface opposite to the abutting surface, and an inner side recess is formed on the inner side surface. Fuel tank.

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.
The mounting member has a plate-like contact portion that contacts the inner surface of the outer wall of the fuel tank, and the contact portion has a contact surface that is fused to the inner surface of the outer wall of the fuel tank. The attachment member can be fixed by fusing with a predetermined area of the inner surface of the outer wall of the tank.

The mounting member has an inner surface on the opposite side of the contact surface, and an inner surface recess is formed on the inner surface, so that when the impact force is applied from the outside to the outer wall of the fuel tank, the mounting member is fused to the outer wall. The impact can be absorbed by being broken by an inner surface recess formed on the inner surface of the contact portion of the member. As a result, the stress on the outer wall of the fuel tank is dispersed, the impact on the outer wall of the fuel tank is reduced, and damage to the outer wall can be prevented.

According to the present invention of claim 2, a plurality of contact surface convex portions are formed on the contact surface, and the inner surface concave portion of the inner surface is formed at a position corresponding to between the contact surface convex portion and the contact surface convex portion. A fuel tank for automobiles.

According to the second aspect of the present invention, a plurality of contact surface convex portions are formed on the contact surface, and the inner surface concave portion of the inner surface is formed at a position corresponding to between the contact surface convex portion and the contact surface convex portion. Therefore, when an impact force is applied to the outer wall of the fuel tank from the outside, it is possible to form an inner surface recess at a portion between the contact surface convex portion where the stress of the contact portion concentrates and the contact surface convex portion. The impact can be absorbed by being broken at the inner surface recess.

In the third aspect of the present invention, the contact surface recess is formed on the contact surface between the contact surface protrusion and the contact surface protrusion, and the inner surface recess is formed at a position corresponding to the contact surface recess. It is a fuel tank for automobiles.

In the third aspect of the present invention, the contact surface recess is formed in the contact surface between the contact surface protrusion and the inner surface recess is formed at a position corresponding to the contact surface recess. The thickness of the abutting part of the part where the abutting surface concave part and the inner side concave part are formed becomes thin, and when stress is concentrated on that part and impact force is applied to the outer wall of the fuel tank from the outside, The impact can be absorbed by being broken at the contact surface recess and the inner surface recess.

The present invention according to claim 4 is the fuel tank for automobiles in which the inner surface concave portion on the inner surface has a plurality of holes or a plurality of grooves formed in a ring shape.

In the present invention of claim 4, when the inner side concave portion is formed in a plurality of holes, the portion corresponding to the portion between the contact surface convex portion and the contact surface convex portion is formed according to the shape of the contact surface. The required number of inner side surface recesses can be formed in the portion where the stress is concentrated, and can be reliably formed.
When a plurality of grooves are formed in a ring shape, the inner surface recess can form an inner surface recess along the shape of the abutting portion and reliably absorb the impact along the ring groove. it can.

The present invention of claim 5 is the fuel tank for automobiles in which the depth of the inner side concave portion is formed to be 1/3 to 1/2 of the thickness of the abutting portion.

In the present invention of claim 5, since the depth of the inner side concave portion is formed to be 1/3 to 1/2 of the thickness of the contact portion, an impact force is applied to the outer wall of the fuel tank from the outside. In some cases, the inner surface recess can be reliably broken to absorb the impact, and the abutting portion has sufficient strength and can hold the built-in component in a normal use state.

According to the sixth aspect of the present invention, the contact surface convex portion is formed with a plurality of pins or protrusions, and the plurality of pins or protrusions enter the inside of the outer wall of the fuel tank and are fused. It is a tank.

In the present invention of claim 6, the contact surface convex portion is formed with a plurality of pins or ridges, and the plurality of pins or ridges enter the inside of the outer wall of the fuel tank and are fused. For this reason, a plurality of contact pins or protrusions 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 seventh aspect of the present invention, the attachment member is a fuel tank for an automobile that is formed separately from or integrally with the built-in component and then engaged with the built-in component.

In the present invention of claim 7, the attachment member is formed separately or integrally with the built-in component and then engaged with the built-in component. For this reason, when formed separately, the mounting member can be easily molded, and the shape of the contact surface of the mounting member can be freely formed. In addition, it is easy to select the material of the mounting member, and it is possible to select a material that is resistant to fuel oil and easily fused to the outer wall of the fuel tank. When formed integrally, it is inexpensive because it can be formed by one molding.

According to the present invention of claim 8, the outer wall of the fuel tank is formed from the outside of the outer wall by five layers of an outer main body layer, an outer adhesive layer, a barrier layer, an inner adhesive layer and an inner main body layer. The inner body layer is made of high density polyethylene (HDPE), the barrier layer is made of ethylene vinyl alcohol copolymer (EVOH), and the outer adhesive layer and the inner adhesive layer are made of high density polyethylene (HDPE) and barrier. It is a fuel tank for automobiles formed of a synthetic resin having adhesiveness in both layers.

In the present invention of claim 8, since the outer main body layer and the inner main body layer are formed of high density polyethylene (HDPE), the outside of the fuel tank has sufficient rigidity and impact resistance, and the inner main body layer has a fuel. Even if it penetrates, the rigidity of the fuel tank can be secured and the impact resistance can be improved.

Since the barrier layer is formed of an ethylene vinyl alcohol copolymer (EVOH), the barrier layer is excellent in gasoline permeation prevention, and can be melt-molded and is excellent in workability. In addition, it has excellent permeation-preventing properties even under high humidity or for gasoline containing alcohol.

Since the external adhesive layer and the internal adhesive layer are formed of a synthetic resin having adhesiveness to both the high density polyethylene (HDPE) and the barrier layer, the external adhesive layer and the internal adhesive layer include the barrier layer, the external adhesive layer, and the external adhesive layer. The main body layer and the inner main body layer can be firmly bonded to each other, and the respective layers of the fuel tank can be firmly bonded and integrated to ensure fuel permeation prevention and strength of the fuel tank.

The mounting member for mounting the built-in components in the fuel tank has an inner surface on the opposite side of the contact surface, and an inner surface recess is formed on the inner surface, so that when an impact force is applied to the outer wall of the fuel tank from the outside The impact can be absorbed by being broken at the inner surface recess. Thereby, the stress to the outer wall of the fuel tank is dispersed, and damage to the outer wall can be prevented.

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 of the attachment surface of the attachment member of the 1st Embodiment of this invention. It is an expanded sectional view of the part of the contact pin of the attachment surface of the attachment member of the 1st Embodiment of this invention. It is sectional drawing of the attachment surface of the attachment member of the 2nd Embodiment of this invention. It is sectional drawing of the state which applied the pressing force to the outer wall of the fuel tank which welded the attachment member of the 1st Embodiment of this invention. It is sectional drawing of the state which applied the pressing force to the outer wall of the fuel tank which welded the attachment member of the 2nd Embodiment 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 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 other conventional attachment member.

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.
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. As will be described later, the skin layer 11 is used when a reproducing member, a filler, or the like is mixed into the external main body layer 12, but the skin layer 11 may be omitted.

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. .

As the high-density polyethylene (HDPE) used for the skin layer 11, the outer main body layer 12, and the inner main body layer 16 described later, for example, the following polyethylene can be specifically used.
The outer main body layer 12 may be formed using a recycled material mainly containing high-density polyethylene (HDPE) as a main material. There are cases where 100% of these recycled materials are used and cases where new high density polyethylene (HDPE) is mixed with the recycled materials.

The barrier layer 14 is made of a thermoplastic synthetic resin that has very little permeation of fuel oil. The thermoplastic synthetic resin constituting the barrier layer 14 is preferably an ethylene vinyl alcohol copolymer (EVOH).
Since the barrier layer 14 is provided, fuel oil such as gasoline that has permeated the inner body layer 16 described later can be prevented from permeating through the barrier layer 14, and the fuel oil can be prevented from evaporating into the atmosphere.

The outer adhesive layer 13 is provided between the outer main body layer 12 and the barrier layer 14 to bond the two layers, and the inner adhesive layer 15 is provided between the inner main body layer 16 and the barrier layer 14. Adhere these two layers. The external adhesive layer 13 and the internal adhesive layer 15 are formed of the same material, and are formed of a synthetic resin having adhesiveness to both the high density polyethylene (HDPE) and the barrier layer 14. For this reason, the external adhesive layer 13 and the internal adhesive layer 15 are firmly bonded to the barrier layer 14, the external main body layer 12 and the internal main body layer 16, respectively, and the respective layers are integrally adhered, It is possible to ensure the fuel permeation preventive property and strength of the fuel tank 1.

As described in the skin layer 11, the inner main body layer 16 uses high-density polyethylene (HDPE) which is the same material as that used by the skin layer 11.
The inner main body layer 16 has a thickness of 15% to 67% of the entire thickness of the outer wall 10 of the fuel tank 1. Since the outer wall 10 has a wall thickness of 3 mm to 8 mm as a whole, it has a wall thickness in the range of 0.45 mm to 5.36 mm. Thereby, since the inner main body layer 16 has sufficient thickness, the outer wall 10 of the fuel tank 1 can maintain rigidity and ensure impact resistance even when swollen with fuel.

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 includes a plurality of column members 21 that support the upper and lower sides of the inner surface of the outer wall of the fuel tank 1 and a beam member 22 that connects the column members 21 to each other.

An attachment member 30 is attached to a tip portion of the column member 21 that contacts the inner surface of the outer wall 10 of the fuel tank 1. In the present embodiment, the mounting member 30 is formed and locked separately from the column member 21 at the tip of the column member 21, but the column member 21 and the mounting member 30 may be integrally formed. Good. The attachment member 30 will be described later.

The column member 21 is attached to a predetermined position inside the fuel tank 1, and the attachment member 30 is attached to the inner surface of the outer wall 10 of the fuel tank 1 to be attached to the fuel tank 1 as will be described later. Thus, a plurality of portions of the outer wall 10 of the fuel tank 1 can be held. Therefore, the strength of the outer wall 10 of the fuel tank 1 can be increased, the expansion and contraction of the fuel tank 1 can be prevented, and the strength can be maintained against an impact.

Further, as shown in the left end portion of FIG. 3, the column member 21 may be provided such that the upper attachment member 30 and the lower attachment member 30 are slightly shifted at the beam member 22 portion.
Furthermore, a dimension change preventing member 23 can be formed on a part of the column member 21 to cope with the contraction or expansion of the outer wall 10 of the fuel tank 1.

The beam member 22 can connect the column members 21 to each other so that the beam member 22 can be attached to a predetermined position on the inner surface of the outer wall of the fuel tank 1. The beam member 22 can be formed in a U-shaped cross section or a hollow shape in order to ensure weight reduction and rigidity.
Further, as shown in FIG. 3, the baffle plate 24 can be integrally formed with the beam member 22. In this case, it is possible to prevent the undulation of fuel in the fuel tank 1 and suppress the flow noise.

In addition to the baffle plate 24, valves connected to various hoses, a sub tank provided inside the fuel tank 1, and the like can be provided on the beam member 22.
Furthermore, a dimension change preventing member 23 can be formed on a part of the beam member 22 in order to cope with the contraction or expansion of the outer wall 10 of the fuel tank 1.

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.

Next, the attachment member 30 will be described. As shown in FIG. 3, the attachment member 30 may be formed in a cylindrical or rectangular tube shape, or may be formed in a flat plate shape.
The case where it forms in a cylindrical shape or a rectangular cylinder shape is demonstrated based on FIGS. 4 is a plan view of the mounting member 30, FIG. 5 is a cross-sectional view of the mounting member 30, FIG. 6 is a bottom view, FIG. 7 is a cross-sectional view along the line AA, and FIG. FIG. FIG. 9 is a plan view of another embodiment of the attachment member 30. 10 and 11 are sectional views showing a state in which an external force is applied to the outer wall 10 of the fuel tank 1.

The attachment member 30 is formed of a connection portion 31 connected to or continuous with the built-in component 20 and a contact portion 32 that contacts the inner surface of the outer wall 10 of the fuel tank 1.
In this Embodiment, the connection part 31 is formed in a cylindrical shape, and the inside is hollow. The inside may be formed in a hollow quadrangular prism shape. A locking portion 38 is formed at the lower end of the connecting portion 31, and when the connecting portion 31 is fitted into the tip of the column member 21, the claw of the locking portion 38 is engaged with the tip of the column member 21, The attachment member 30 is firmly attached.
The flat mounting member 30 does not have the connecting portion 31, and is attached to the tip of the column member 21 by directly engaging or adhering to the protrusion provided on the lower surface of the contact portion 32 or the bonding surface.

In the present embodiment, the contact portion 32 is formed in a plate shape, a circular contact surface 33 facing the inner surface of the outer wall 10 of the fuel tank 1, and the fuel tank from the contact surface 33 as a contact surface convex portion. A plurality of contact pins 34 projecting toward one outer wall 10 are formed. The contact pin 34 is formed in a columnar shape or a truncated cone shape having a circular or elliptical cross-sectional shape. Although the contact pin 34 is formed in a columnar shape, the contact pin 34 can be formed in a truncated cone shape, or can be formed in an elliptical column shape or an elliptical section and a truncated cone shape.
Further, as will be described later, arc-shaped protrusions as shown in FIG. 14 may be formed on the contact surface 33 as convex portions of the contact surface.

As shown in FIGS. 7 and 8, a contact surface recess 36 is formed on the contact surface 33 at the base of the contact pin 34 so as to surround the periphery of the contact pin 34. For this reason, the contact pin 34 is easily bent to the left and right by the contact surface recess 36, and even if an impact, bending stress, bending, or the like is applied to the outer wall 10 of the fuel tank 1, the stress is dispersed in the contact surface recess 36. The impact on the welded portion of the contact pin 34 and the outer wall 10 of the fuel tank 1 is reduced, and the stress absorbability of the outer wall 10 of the fuel tank 1 can be further improved.

The contact portion 32 has an inner surface 37 on the opposite side of the contact surface 33. A plurality of inner side surface recesses 39 are formed on the inner side surface 37. As will be described later, when an impact is applied to the outer wall 10 of the fuel tank 1, the inner side recess 39 breaks the inner side recess 39, absorbs the impact, and impacts the outer wall 10 of the fuel tank 1. Can be reduced, and damage to the outer wall 10 can be prevented.

The inner surface recess 39 is formed on the inner surface 37 at a position corresponding to the space between the contact pin 34 and the contact pin 34 which are a plurality of contact surface convex portions formed on the contact surface 33. For this reason, as shown in FIGS. 10 and 11, when an impact force is applied to the outer wall 10 of the fuel tank 1 from the outside, an inner surface recess 39 may be formed in a portion where the stress of the contact portion 32 is concentrated. The abutting portion 32 can be broken by the inner side concave portion 39 to absorb the impact, and the breaking does not continue to the outer wall 10 of the fuel tank 1.

Further, as shown in FIG. 8, a contact surface recess 36 is formed around the contact pin 34, and an inner surface 37, which is a surface opposite to the contact surface 33 on which the contact surface recess 36 is formed, is formed. It is also possible to form the inner surface recess 39 in the corresponding part. In this case, the inner side recess 39 is easily broken by an impact.
Furthermore, as shown in FIG. 9, when the contact surface recess 36 is formed around the contact pin 34 without the contact pin 34 protruding from the contact surface 33, the contact surface recess is similarly formed. It is also possible to form the inner side concave portion 39 in a corresponding portion of the inner side surface 37 that is the surface opposite to the contact surface 33 on which the 36 is formed.

FIG. 10 shows a case where an external force is applied to a portion where the outer wall 10 of the fuel tank 1 is flat, and FIG. 11 shows a case where an external force is applied to a portion where the outer wall 10 of the fuel tank 1 is recessed. In any case, even if an external force is applied, the stress concentrates on the inner side concave portion 39 formed on the inner side surface 37 so that the inner side concave portion 39 is not broken and the outer wall 10 is not damaged.

The inner surface recess 39 of the inner surface 37 can be formed in a plurality of holes. In this case, a plurality of hole-shaped inner side surface recesses 39 are formed on the corresponding inner side surface 37 between the contact pins 34 formed on the contact surface 33 so as to surround the contact pins 34. Therefore, the plurality of hole-shaped inner side surface recesses 39 can be reliably formed in a portion where stress is concentrated.

Further, the inner side surface recess 39 of the inner side surface 37 can form a plurality of grooves in a ring shape. In this case, along the shape of the contact portion 32, for example, a ring-shaped inner surface recess 39 is formed on the disk-shaped inner surface 37, and the impact force is applied to the outer wall 10 of the fuel tank 1 from any direction. Even if added, the impact can be absorbed.

In addition, it is preferable to form the depth of the inner surface concave portion 39 to a depth of 1/3 to 1/2 of the thickness of the contact portion 32. In this case, when an impact force is applied to the outer wall 10 of the fuel tank 1 from the outside, the inner surface recess 39 can be broken to absorb the impact, and the contact portion 32 is sufficient in a normal use state. The built-in component 20 can be held with sufficient strength.
Further, when the depth of the inner surface recess 39 is 1/3 to 1/2 of the thickness of the contact portion 32 and the contact surface recess 36 is formed, The total depth of the contact surface recess 36 can be made.

If the depth of the inner side concave portion 39 is shallower than 1/3 of the thickness of the contact portion 32, the inner side concave portion 39 may not be reliably broken by an impact. If it is deeper than 2, it will be broken by a small impact and the built-in component 20 cannot be held. For example, when the thickness of the contact portion 32 is 3 mm, the depth of the inner side surface recess 39 is about 1 to 1.5 mm.

The height of the contact pin 34 formed on the contact surface 33 of the contact portion 32 is about 0.5 to 2 mm from the contact surface 33, and the depth of the contact surface recess 36 is the contact surface 33. From about 1 mm, the width of the contact surface recess 36 is about 0.3 mm.
When the fuel tank 1 is formed by blow molding and the attachment member 30 is welded to the inner surface of the outer wall 10, the top portion 35 of the contact pin 34 is melted by the heat of the outer wall 10 and welded to the inner surface of the outer wall 10.

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.

The abutment portion 32 may be formed with a protrusion that protrudes from the abutment surface 33 as a contact surface convex portion and has a triangular cross-sectional shape at the tip, and enters the inside of the outer wall 10 of the fuel tank 1. As shown in FIG. 14, a plurality of protrusions are formed in a circular arc shape in parallel. Therefore, the contact surface 33 can be firmly welded to the outer wall of the fuel tank 1 in all directions without being displaced in either direction of the contact surface 33.

It is preferable that the space | interval of the vertex of a protrusion is 1 mm-3 mm. In this case, when the contact portion 32 is pressed against the inner surface of the outer wall of the fuel tank 1, the protrusion enters the outer wall 10 of the fuel tank 1, which is a parison 8, and the fuel tank 1 melted between the protrusion and the protrusion. The outer wall 10 of the fuel tank 1 can enter, and the outer wall 10 of the fuel tank 1 and the contact surface 33 can be firmly fixed.
An arcuate inner side surface recess 39 can be formed on the inner side surface 37 corresponding to the ridge.

Next, a method for manufacturing the fuel tank 1 of the present invention by blow molding will be described with reference to FIG.
First, as shown in FIG. 12, 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, 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, as described above, the protrusion of the contact portion 32 of the attachment member 30 enters the inner surface of the parison 8, and the contact portion 32 and the parison 8 are fused. be able to. 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.

Thereafter, 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, the blow molding die 40 is closed, and the parison 8 is cut by the slide cutter 46. . 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 20 Built-in component 30 Mounting member 32 Contact part 33 Contact surface 34 Contact pin 37 Inner side surface 39 Inner side surface recessed part 40 Blow molding die

Claims (8)

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 has a contact portion that contacts the inner surface of the outer wall of the fuel tank. The contact portion has a contact surface that is fused to the inner surface of the outer wall of the fuel tank, and an inner surface opposite to the contact surface, and an inner surface recess is formed on the inner surface. A fuel tank for automobiles. The contact surface according to claim 1, wherein a plurality of contact surface convex portions are formed on the contact surface, and the inner surface concave portion is formed at a position corresponding to between the contact surface convex portion and the contact surface convex portion. Automotive fuel tank. The contact surface recess is formed in the contact surface between the contact surface protrusion and the contact surface protrusion, and the inner side recess is formed at a position corresponding to the contact surface recess. The fuel tank for automobiles according to claim 2. The automobile fuel tank according to claim 1 or 2, wherein the inner surface recess has a plurality of holes or a plurality of grooves formed in a ring shape. The depth of the said inner surface recessed part is formed in the depth of 1/3 to 1/2 of the thickness of the said contact part, The fuel tank for motor vehicles of any one of Claims 1 thru | or 4 formed. . The contact surface convex portion is formed with a plurality of pins or ridges, and the plurality of pins or ridges enter the inside of the outer wall of the fuel tank and are fused. The fuel tank for automobiles according to claim 1. The automobile fuel tank according to any one of claims 1 to 5, wherein the mounting member is formed separately or integrally with the built-in component and then engaged with the built-in component. The outer wall of the fuel tank is formed of five layers of an outer main body layer, an outer adhesive layer, a barrier layer, an inner adhesive layer and an inner main body layer from the outer side of the outer wall. The barrier layer is formed of ethylene vinyl alcohol copolymer (EVOH), and the outer adhesive layer and the inner adhesive layer are formed on both the high density polyethylene (HDPE) and the barrier layer. The automobile fuel tank according to any one of claims 1 to 7, wherein the fuel tank is formed of an adhesive synthetic resin.