JP2009132296A - Fuel tank for automobile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel tank that can absorb excessive stress and strain even if the fuel tank contracts or expands. <P>SOLUTION: A fuel tank 1 for an automobile is formed by blow molding, and has a built-in part 20 mounted inside and an outer wall formed with thermoplastic synthetic resin. In this fuel tank, the built-in part 20 is formed integrally with the synthetic resin. A plurality of mounting members 30, which mount the built-in part 20 by being fusion-bonded on the inner surface of the outer wall of the fuel tank 1, are provided on the built-in part 20. Dimensional-change-absorbing members 23, which can bend according to the contraction or expansion of the fuel tank 1, are provided on the built-in part 20. <P>COPYRIGHT: (C)2009,JPO&INPIT

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 component 120 is 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 to fix the built-in component 120 to the fuel tank. Some are attached inside (see, for example, Patent Document 1).

  However, in this case, since the built-in component 120 is 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. May increase and 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 208 enters the blow molding mold 240, the built-in component 220 is placed on the support rod 241, and the blow molding mold 240 is opened and positioned therein. Thereafter, the parison 208 is lowered while the blow molding die 240 remains open so that the built-in component 220 is positioned inside the parison 208.

Thereafter, as shown in FIG. 13, before closing the blow molding die 240, the pressing pins 242 are taken out from both sides of the blow molding die 240, the parison 208 is pressed, and the parison 208 is moved to the side end of the built-in component 220. Press. At this time, since the inner surface of the parison 208 is not yet solidified, the side ends of the parison 208 and the built-in component 220 can be fused.
Then, the support bar 241 is lowered, the blow molding die 240 is closed, and air is blown to perform blow molding.

  In this case, the fuel tank contracts after blow molding, and further expands and contracts during use due to the internal pressure of the fuel tank, temperature, and the like. Further, when the fuel tank and the built-in component 220 swell during use, the expansion ratio differs between the fuel tank and the built-in component 220 due to the difference in the degree of swelling. In this case, the built-in component 220 and the fuel tank are undesirably strained and stressed.

  Moreover, in order to improve the intensity | strength of a fuel tank, the upper and lower outer walls may be dented and it may weld in several places. However, in this case, since the outer walls are partially recessed and welded, the internal volume of the fuel tank is reduced. Even in this case, distortion and stress were applied to the welded portion due to expansion and contraction of the fuel tank, which was not preferable.

JP-A-1-301227 JP-A-6-143396

  Therefore, an object of the present invention is to provide a fuel tank that can absorb excessive stress and strain even when the fuel tank contracts or expands.

The present invention of claim 1 for solving the above-mentioned problems 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 thermoplastic synthetic resin.
The built-in parts are integrally formed of synthetic resin, and the built-in parts are 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 parts. According to the present invention, there is provided a fuel tank for an automobile provided with a dimension change absorbing member that can be bent according to the above.

  In the first aspect of the present invention, the built-in component is integrally formed of a synthetic resin, and 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 attach the built-in component. For this reason, the built-in component can be fused and fixed to the inner surface of the outer wall of the fuel tank with the mounting member, and can be mounted stably, and the strength of the outer wall of the fuel tank can be increased by the built-in component.

  The built-in component is provided with a dimension change absorbing member that can be bent in accordance with the contraction or expansion of the fuel tank. For this reason, even if the outer wall of the fuel tank contracts or expands, or the built-in component and the fuel tank swell, the dimensional change absorbing member bends and absorbs the change, and the fuel tank and the built-in component are distorted or excessively distorted. Since no stress is applied, the strength of the fuel tank can be maintained without peeling off the fuel tank and the built-in components.

  According to the second aspect of the present invention, the built-in component includes a plurality of column members that are in contact with the upper and lower sides of the outer wall of the fuel tank, and a column member integrally connected to each other in the lateral direction of the fuel tank. It is a fuel tank for automobiles, which is formed from an extended beam member, and in which a dimension change absorbing member is formed on each of a column member and a beam member.

  According to the second aspect of the present invention, the built-in component includes a plurality of column members that are in contact with the upper and lower sides of the outer wall of the fuel tank, and the column members integrally connected to each other in the lateral direction of the fuel tank. It is formed from an extended beam member. For this reason, the upper and lower sides of the outer wall of the fuel tank can be supported by the pillar member to increase the strength and to maintain the contraction and expansion of the fuel tank. The column members can be integrally connected by the beam members, and the column members can be attached to predetermined positions of the fuel tank, so that blow molding is easy.

  Since the dimension change absorbing member is formed on each of the column member and the beam member, the dimension change absorbing member attached to the column member is bent even if the fuel tank expands or contracts or the built-in component and the fuel tank swell. Thus, the pillar member and the outer wall of the fuel tank do not peel off, and the strength of the fuel tank can be maintained. In addition, the impact on the fuel tank can be absorbed. The dimension change absorbing member formed on the beam member can absorb the expansion and contraction of the fuel tank in the lateral direction, and the position of the column member in the fuel tank can be maintained.

  In the third aspect of the present invention, the built-in component is formed by integrally connecting a plurality of box-shaped objects, and forms a column member that contacts the upper side and the lower side of the outer wall of the fuel tank, respectively. The column members are fuel tanks for automobiles in which dimension change absorbing members are respectively formed and dimension change absorbing members are formed at connecting portions that integrally connect box-like objects.

In the third aspect of the present invention, the built-in component is formed by integrally connecting a plurality of box-shaped objects, so that it is possible to prevent the generation of a sound wave of the fuel oil inside the fuel tank. A canister such as a fuel pump can be installed in the object.
Since the columnar members are formed with column members that contact the upper and lower sides of the outer wall of the fuel tank, the column members support the upper and lower sides of the outer wall of the fuel tank to increase the strength and the fuel tank contracts. Even if it expands, the strength of the fuel tank can be maintained.

  Each of the column members is formed with a dimension change absorbing member, and each dimension change absorbing member is formed at a connecting portion that integrally connects the box-shaped objects. For this reason, even if the fuel tank expands or contracts, or even if the built-in components and the fuel tank swell, the dimension change absorbing member attached to the column member bends and the column member and the outer wall of the fuel tank peel off. The strength of the fuel tank can be maintained. In addition, the impact on the fuel tank can be absorbed. The dimensional change absorbing member formed in the connecting part that connects the box-shaped objects integrally can absorb the expansion and contraction of the fuel tank in the lateral direction and maintain the position of the box-shaped objects in the fuel tank. Can do.

  According to a fourth aspect of the present invention, there is provided a fuel tank for an automobile in which the dimension change absorbing member is provided with a stopper member in the extending direction or the contracting direction.

  In the fourth aspect of the present invention, since the dimension change absorbing member is formed with the stopper member in the extending direction or the contracting direction, the tank can be prevented from being excessively deformed due to the change in the tank internal pressure.

  According to a fifth aspect of the present invention, the dimension change absorbing member is a fuel tank for an automobile in which the cross-sectional shape is elliptical and the elliptical portion is bent and compressed or expanded.

  In the fifth aspect of the present invention, the dimension change absorbing member has an elliptical cross-sectional shape, and the elliptical portion is bent and compressed or stretched. Therefore, the dimension change absorbing member can be easily manufactured by injection molding of synthetic resin or the like. It is also easy to form.

  According to the sixth aspect of the present invention, 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 6, since the outer main body layer and the inner main body layer are made of high density polyethylene (HDPE), the outer side 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.

  According to a seventh aspect of the present invention, the attachment member is an automobile fuel tank that is formed separately from the built-in component and then engaged with the built-in component.

  In the present invention of claim 7, since the mounting member is formed separately from the built-in component and then engaged with the built-in component, the mounting member can be easily molded, and the shape of the contact surface of the mounting member is It can be freely formed. Moreover, 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 welded to the outer wall of the fuel tank.

  In the present invention, since the dimension change absorbing member that can be bent according to the contraction or expansion of the fuel tank is provided inside or near the tip of the built-in component, even if the outer wall of the fuel tank contracts or expands, the dimension change absorption member The bending of the fuel tank and the change is absorbed, and the fuel tank and the built-in components are not strained or excessively stressed. Therefore, the fuel tank and the built-in components are not peeled off, and the strength of the fuel tank can be maintained. .

  An automotive fuel tank 1 according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view of a fuel tank 1 according to an embodiment of the present invention. FIG. 2 is a partial cross-sectional view of an outer wall 10 of a fuel tank 1 made of thermoplastic synthetic resin. The configuration is shown.

3 and 4 are perspective views showing the built-in component 20 of the fuel tank 1 in the embodiment of the present invention, and FIGS. 7 and 8 are built-in components of the fuel tank 1 in another embodiment of the present invention. FIG. 5 and 6 are sectional views of the dimension change absorbing member 23 of the present invention.
9-11 is a figure which shows the process of blow-molding which manufactures the fuel tank 1. FIG.

  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 made smooth without the inorganic filler coming out 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.
High density polyethylene (HDPE) having a melt flow rate (MRF: 21.6 kg / 10 min) of 5 to 7 and a density (g / cm 3) of 0.944 to 0.950 can be used. .

The outer main body layer 12 may be formed using a recycled material mainly containing high-density polyethylene (HDPE) as a main material. Recycled materials mainly containing high-density polyethylene (HDPE) are used, for example, when the fuel tank 1 collected after use is crushed and recycled and used during the manufacturing process of the fuel tank 1 In some cases, scraps and defective products generated in the above are crushed and recycled. Since the fuel tank 1 is mainly composed of high density polyethylene (HDPE), the recycled material obtained by pulverizing the fuel tank 1 mainly has high density polyethylene (HDPE).
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, for example, ethylene vinyl alcohol copolymer (EVOH), polybutylene terephthalate, polyethylene terephthalate, polyphenylene sulfide (PPS), liquid crystal polymer (LCP), semi-aromatic nylon (PPA). Can be used, but ethylene vinyl alcohol copolymer (EVOH) is preferred.
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.

  When an ethylene vinyl alcohol copolymer (EVOH) is used as the barrier layer 14, the barrier layer 14 is excellent in gasoline permeation prevention and can be melt-molded and processed. Moreover, it is excellent in gasoline permeation prevention even under high humidity. Furthermore, it can have excellent permeation resistance for gasoline containing alcohol.

  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 an adhesive thermoplastic synthetic resin used for the external adhesive layer 13 and the internal adhesive layer 15, for example, a modified polyolefin resin can be used, and an unsaturated carboxylic acid modified polyolefin resin, particularly an unsaturated carboxylic acid. A modified polyethylene resin is preferred. This can be produced by copolymerizing or graft-polymerizing an unsaturated carboxylic acid to a polyolefin resin.

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 or FIG. 7 is attached to the inside of the fuel tank 1. A method for attaching the built-in component 20 will be described later.
First, the built-in component 20 of the first embodiment will be described with reference to FIGS. 3 and 4. The built-in component 20 of the second embodiment will be described later. 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 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 fused to the upper and lower inner surfaces of the outer wall of the fuel tank 1 as will be described later. A plurality of portions on the upper and lower sides of the outer wall of the fuel tank 1 can be held. For this reason, the strength of the outer wall 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 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.
Further, a dimensional change absorbing member 23 is formed in a part of the column member 21 to cope with the contraction or expansion of the outer wall of the fuel tank 1. The dimension change absorbing member 23 will be described later.

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.
Further, a dimensional change absorbing member 23 can be formed on a part of the beam member 22 to cope with the contraction or expansion of the outer wall 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.

  In the present embodiment, the dimension change absorbing member 23 is formed integrally with the column member 21 at the lower portion of the column member 21 as shown in FIGS. 3 and 4. The shape has the bending part 23a formed in the plate shape whose cross section is an ellipse. As the bending portion 23a expands and contracts in the fuel tank 1 and the column member 21 and the beam member 22 swell, the elliptical portion bends and compresses or expands, so that the expansion and contraction of the fuel tank 1 can be absorbed. Accordingly, no strain or excessive stress is applied to the fuel tank 1 and the built-in component 20, so that the column members 21 of the fuel tank 1 and the built-in component 20 do not peel off, and the strength of the fuel tank 1 can be maintained. it can.

  The dimension change absorbing member 23 is also formed on the beam member 22. Even when the beam member 22 swells or the fuel tank 1 expands or contracts in the lateral direction, the expansion and contraction can be absorbed by the dimension change absorbing member 23 formed on the beam member 22. The position in the fuel tank 1 can be maintained.

  A stopper member that prevents an excessive dimensional change of the bending portion 23 a can be provided inside the dimensional change absorbing member 23. In the embodiment of FIG. 4, the stopper member is a parallel plate-like shape from the lower part of the dimension change absorbing member 23, bent at a right angle so that the front ends thereof face each other, and a gap is generated between the front ends. The portion 23b and the T-shaped head portion formed in a T shape enter the gap at the tip of the lower locking portion 23b. The leg portion is composed of an upper locking portion 23 c that extends downward from the upper portion of the dimension change absorbing member 23.

When the fuel tank 1 contracts and the dimension change absorbing member 23 is compressed, the T-shaped head portion of the upper locking portion 23c comes into contact with the lower surface of the dimension change absorbing member 23, and the dimension change absorbing member 23 beyond that. The deformation of the bending portion 23a is prevented.
When the fuel tank 1 is expanded and the dimensional change absorbing member 23 is expanded, the T-shaped head portion of the upper locking portion 23c is locked to the bent portion at the tip of the lower locking portion 23b, and the dimension is larger than that. The extension of the bending portion 23a of the change absorbing member 23 is prevented.
For this reason, excessive deformation of the dimensional change absorbing member 23 due to impact or the like can be prevented, distortion of the fuel tank 1 can be prevented from increasing, and the dimensional change absorbing member 23 can be prevented from being destroyed.

5 and 6 show other forms of the dimension change absorbing member 23. FIG.
In the form of FIG. 5, the lower locking portion 23 b extends slightly laterally from the tip of the lower column member 21 and extends upward from the tip. A bent portion 23a is formed in a lateral S shape from both ends of the lower locking portion 23b, and the tip is continuous with the tip of the upper column member 21.

The upper locking portion 23c extends downward from the tip of the upper column member 21 so as to wrap the outside of the lower locking portion 23b, and the lower locking portion 23b is slightly on both sides from the tip of the lower column member 21. It is formed by bending at a right angle so as to wrap the lower part of the laterally projecting portion. The bending of the bending portion 23a prevents the fuel tank 1 and the built-in component 20 from expanding, compressing, and swelling.
For this reason, when the fuel tank 1 expands and the bending portion 23a is excessively extended, the tip of the upper locking portion 23c comes into contact with the lower surface of the lower locking portion 23b to prevent further expansion. Can do.

In the form of FIG. 6, the lower locking portion 23 b extends slightly laterally from the tip of the lower column member 21 and extends upward from the tip.
The upper locking portion 23c extends downward from the tip of the upper column member 21 so as to wrap the outside of the lower locking portion 23b, and the bending portion 23a is curved in a C-shaped cross section from the side outer surface of the upper locking portion 23c. Then, it is connected to the tip portion of the lower column member 21.

The upper locking portion 23c extends downward from the tip of the upper column member 21 so as to wrap the outside of the lower locking portion 23b, and the lower locking portion 23b is slightly on both sides from the tip of the lower column member 21. It is formed by bending at a right angle so as to wrap the lower part of the laterally projecting portion. Similar to the embodiment of FIG. 5, absorption is performed by the bending portion 23 a.
For this reason, when the fuel tank 1 expands and the bending portion 23a is excessively expanded, the tip of the upper locking portion 23c comes into contact with the lower surface of the lower locking portion 23b to prevent further expansion. Can do.

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 FIG.

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 of the fuel tank 1.
In this Embodiment, the connection part 31 is formed in a cylindrical shape, and the inside is hollow. 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.
In the flat mounting member 30, the connecting portion 31 is a protrusion or an adhesive surface provided on the lower surface of the abutting portion 32, and is locked or adhered to the tip of the column member 21 by the protrusion or the adhesive surface. Installed.

  The contact portion 32 includes a circular contact surface 33 that is in close contact with the inner surface of the outer wall of the fuel tank 1, and a protrusion 34 that protrudes from the contact surface 33 and has a triangular cross-sectional shape and enters the inside of the outer wall of the fuel tank 1. Is formed. In the form of FIG. 3, a plurality of protrusions 34 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.

  The interval between the vertices 35 of the protrusions 34 is preferably 1 mm to 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 34 enters the outer wall of the fuel tank 1, which is the parison 8, and the fuel melted between the protrusion 34 and the protrusion 34. The outer wall of the tank 1 can enter, and the outer wall of the fuel tank 1 and the contact surface 33 can be firmly fixed.

  As shown in FIG. 4, four air vent grooves 36 are formed in the radial direction across the protrusion 34. Therefore, when the contact surface 33 is pressed against the outer wall of the fuel tank 1, air between the protrusion 34 and the outer wall of the fuel tank 1 can be discharged, and the outer wall and the contact surface 33 of the fuel tank 1 can be discharged. Can be adhered.

  Next, the built-in component 20 according to the second embodiment of the present invention will be described with reference to FIGS. The built-in component 20 is formed by integrally connecting a plurality of box-like objects 25. The box-shaped object 25 has a space inside, and a plurality of holes 26 are formed in each portion. For this reason, the fuel oil in the fuel tank 1 can freely enter and exit the box-like object 25, and the fuel oil in the fuel tank 1 can be prevented from being waved and the occurrence of wave noise. . Further, a canister such as a fuel pump can be mounted in the box-like object.

  Columnar members 21 are formed on the box-like object 25 so as to come into contact with the upper and lower sides of the outer wall of the fuel tank 1, respectively. For this reason, the box-like object 25 can be attached to the fuel tank 1 by the pillar member 21 at a predetermined position. Further, the pillar member 21 supports the upper and lower sides of the outer wall of the fuel tank 1 to increase the strength and to maintain the contraction and expansion of the fuel tank 1. The attachment member 30 is attached to the tip of the column member 21 as in the first embodiment.

  As with the first embodiment described above, the column member 21 is formed with a dimension change absorbing member 23, respectively. Moreover, the dimension change absorption member 23 is formed in the connection part which connects the box-shaped object 25 integrally, respectively. The box-like object 25 may be connected by the dimension change absorbing member 23, or may be connected by the beam member 22, and the dimension change absorbing member 23 may be formed on the beam member 22.

Since the dimension change absorbing member 23 is formed on the column member 21, the dimension change absorbing member 23 attached to the column member 21 bends even if the fuel tank 1 or the box-like object 25 expands or contracts. The outer wall of 1 does not peel off, and the strength of the fuel tank 1 can be maintained. Further, the impact on the fuel tank 1 can be absorbed.
The dimension change absorbing member 23 formed in the connecting portion that integrally connects the box-shaped object 25 can absorb the expansion and contraction of the fuel tank 1 and the box-shaped object 25 in the lateral direction. The position in the fuel tank 1 can be maintained.

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, as described above, the protrusion 34 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. can do. 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 of the fuel tank 1.

  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.

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 front view of the built-in component attached inside the fuel tank of this invention. It is sectional drawing of the dimension change absorption member of this invention. It is other sectional drawing of the dimension change absorption member of this invention. It is a perspective view of other built-in components attached to the inside of the fuel tank of the present invention. It is a top view of other built-in components attached inside the fuel tank of the present invention. 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 opened the blow molding die which shows the other 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 other conventional fuel tank manufacturing method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel tank 8 Parison 10 Outer wall 20 Built-in part 21 Column member 22 Beam member 23 Dimensional change absorption member 23a Deflection part 25 Box-shaped object 30 Mounting member 31 Connection part 32 Contact part 40 Blow molding die 41 Support rod 42 Press pin 45 Air nozzle

Claims (7)

In an automotive fuel tank that is formed by blow molding, has built-in components inside, and has an outer wall formed of thermoplastic synthetic resin,
The built-in component is integrally formed of a synthetic resin, and the built-in component is provided with a plurality of attachment members that are fused to the inner surface of the outer wall of the fuel tank to attach the built-in component. A fuel tank for an automobile, comprising a dimension change absorbing member that can be bent in response to contraction or expansion of the fuel tank.   The built-in component extends in the lateral direction of the fuel tank by integrally connecting the column members with a plurality of column members whose both ends are in contact with the upper and lower sides of the outer wall of the fuel tank. The automobile fuel tank according to claim 1, wherein the fuel tank is formed of a beam member, and a dimension change absorbing member is formed on each of the column member and the beam member.   The built-in component is formed by integrally connecting a plurality of box-shaped objects, and forms column members that contact the upper and lower sides of the outer wall of the fuel tank, respectively. 2. The fuel tank for automobiles according to claim 1, wherein dimension change absorbing members are respectively formed, and the dimension change absorbing members are respectively formed at connecting portions that integrally connect the box-like objects.   The fuel tank for automobiles according to any one of claims 1 to 3, wherein the dimension change absorbing member is formed with a stopper member in an extending direction or a contracting direction.   5. The automobile fuel tank according to claim 1, wherein the dimension change absorbing member has an elliptical cross-sectional shape, and the elliptical portion is bent and compressed or expanded.   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 5, wherein the fuel tank is formed of an adhesive synthetic resin.   The fuel tank for an automobile according to any one of claims 1 to 6, wherein the mounting member is formed separately from the built-in component and then engaged with the built-in component.

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