JP2008155877A - Fuel tank - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel tank having an upper shell part and a lower shell part formed separately from each other and equipped with a fuel pump unit or the like inside, which is capable of easily opening an inspection opening part. <P>SOLUTION: A fuel tank 1 comprises inner resin layers 15, 25, and outer sheet layers 16, 26 for covering outer surface of the inner resin layers, and joining peripheral edge parts of an upper shell part 10 and a lower shell part 20 are integrally bonded to each other. An inspection opening part 13 of components is provided in a part of an outer wall of a shell part. The inspection opening part 13 is closed by a lid part 13a. The lid part is covered by the outer sheet layers. An inspection opening part screw part 14 capable of mounting an opening part opening/closing lid 50 for closing the inspection opening part when the lid part is separated is formed on the inner resin layers of the inspection opening part. The lid part is separable from the outer sheet layers when inspecting the components in the fuel tank. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a fuel tank made of a thermoplastic synthetic resin, which is formed by joining an upper shell portion and a lower shell portion, which are separately divided and formed by injection, and formed by welding.

Conventionally, blow molding methods have been often used for large fuel tanks such as automobile fuel tanks because of the ease of forming a hollow body. In the blow molding method, a melted synthetic resin parison is formed into a cylindrical shape and extruded from above, the parison is sandwiched between molds, and air is blown into the parison to manufacture a fuel tank.

However, in this method, in the case of a large fuel tank such as an automobile fuel tank, the overall weight of the parison increases, and when strength such as an automobile fuel tank is required, the strength is increased. When manufacturing a thick fuel tank, the weight of the parison also increases and droops downward when the molten parison is put into the mold from the top of the molding machine. There was also a case where it became thin.
In addition, in the case of a product with a complicated shape, when the parison is expanded in the mold, the expansion ratio of the parison may vary depending on the part of the product, and the thickness of the product may vary. It was.

Also, blow molded fuel tanks are difficult to install accessories such as pumps and valves in the fuel tank, and it is difficult to provide ribs and beams, etc. Hole drilling is required, and a structure in which the accessory is modularized and attached to the drilled portion with a screw or the like via a gasket is required. In that case, the structure of the accessory fuel pump and the like was complicated and the number of parts was increased. Also, when checking the accessories, the entire module was removed, which was troublesome.

Therefore, the synthetic resin hollow body is divided into upper and lower parts, and the upper shell part and the lower shell part are separately molded by injection molding or the like, and then the joining peripheral edge parts of the upper shell part and the lower shell part are welded to each other to form a fuel tank The method of forming is also performed (for example, refer patent document 1). In this case, accessories such as a fuel pump can be easily attached before the upper shell portion and the lower shell portion are welded. In addition, mounting ribs, beams and the like can be easily formed on the inner surfaces of the upper shell portion and the lower shell portion.

As shown in FIG. 19, in the fuel tank 101 that fuses the upper shell portion 110 and the lower shell portion 120, the outer side of the fuel tank 101 has a fuel permeation-proof property in order to prevent fuel permeation from the fuel tank 101. There is one in which the outer sheet layers 116 and 126 are covered and the inner side is formed with the inner resin layers 115 and 125 (see, for example, Patent Document 2).
In some cases, an outer sheet having resistance to permeation of fuel is bonded to the outside of the fuel tank (see, for example, Patent Document 3).

On the other hand, as shown in FIG. 20, when the upper shell portion 210 and the lower shell portion 220 are formed separately and then the fuel pump unit 204 and the like attached to the lower shell portion 220 in the fuel tank 201 welded are inspected and repaired. In this case, it is necessary to form an inspection opening 213 in the upper shell portion 210. In this case, for example, when the fuel tank 201 is manufactured, the opening portion 213 of the upper shell portion 210 is closed with a lid portion 213 a formed integrally with the opening portion 213. And when inspecting and repairing, the cover part 213a is cut | disconnected and opened from the part of the groove part 213c formed between the opening part 213 and the cover part 213a (for example, refer patent document 4).

However, in this case, since the lid portion 213a is cut and removed, it is difficult to cover the outside of the fuel tank 201 with a fuel-permeable sheet. Therefore, the material forming the upper shell part 210 and the lower shell part 220 needs fuel permeability, and may be low in moldability or expensive, or may not be sufficient to prevent fuel permeability. There was little room for material selection.
JP-A-11-34180 Japanese Patent Application Laid-Open No. H5-16938 JP-A-2005-343451 US Pat. No. 6,179,145

  Thus, there is a need for a fuel tank with excellent fuel permeation resistance that can easily open the inspection opening when the upper shell portion and the lower shell portion are formed separately and a fuel pump unit or the like is mounted inside. It was done.

The present invention of claim 1 for solving the above-mentioned problems is a fuel tank made of thermoplastic synthetic resin,
Each of the fuel tanks is integrally formed by joining and joining the upper shell part and the lower shell part separately molded by injection molding, and the upper shell part and the lower shell part each have an inner resin layer, It is composed of an outer sheet layer that covers the outer surface of the inner resin layer,
A part of the outer wall of the upper shell part or the lower shell part is provided with an inspection opening for parts in the fuel tank. The inspection opening is closed by a lid, and the lid is covered by an outer sheet layer. When inspecting parts in the tank, it is formed so as to be separable together with the outer sheet layer, and when the lid is separated, an opening opening / closing lid that closes the inspection opening can be attached to the inner resin layer of the inspection opening. This is a fuel tank in which an inspection opening thread portion is formed.

In the first aspect of the present invention, the fuel tank is integrally configured by fusing the joint peripheral portions of the upper shell portion and the lower shell portion that are separately molded by injection molding. For this reason, the fuel tank formed by combining the upper shell portion and the lower shell portion can obtain a precise and high strength product with high dimensional accuracy. Also, component mounting ribs and reinforcing ribs can be formed inside the upper shell portion and the lower shell portion, and built-in components and the like can be easily mounted. Since the joint peripheral portions of the molded upper shell portion and lower shell portion are fused, the joint peripheral portions of the upper shell portion and the lower shell portion are firmly and integrally joined, and the upper shell portion and the lower shell are combined. Since the strength of the joining portion of the part is increased and an adhesive or the like for joining is unnecessary, manufacturing is easy.

The upper shell portion and the lower shell portion are each composed of an inner resin layer and an outer sheet layer covering the outer surface of the inner resin layer. Therefore, a resin having high strength and excellent moldability can be selected for the inner resin layer, and a sheet having excellent fuel permeation resistance can be used for the outer sheet layer, which is easy to manufacture.

A part of the outer wall of the upper shell part or the lower shell part is provided with an inspection opening for parts in the fuel tank. The inspection opening is closed by a lid, and the lid is covered by the outer sheet layer. For this reason, until the inspection opening is opened, the inspection opening can be completely blocked, and fuel can be prevented from permeating through the inspection opening.

The lid is separable with the outer sheet layer when inspecting the components in the fuel tank, and when the lid is separated from the inner resin layer of the inspection opening, the opening is opened and closed to close the inspection opening. An inspection opening thread portion to which the lid can be attached is formed. For this reason, the lid portion and the outer sheet layer corresponding to the lid portion can be easily separated and removed at the time of inspecting the components in the fuel tank, and inspection and repair can be performed from the inspection opening. In addition, after inspection and repair are completed, the opening opening lid that closes the inspection opening can be screwed to the inspection opening screw, and the inspection opening can be securely attached by screwing through the sealing. Can be closed.

According to a second aspect of the present invention, the lid is formed integrally with the inspection opening, and is formed so as to be cuttable when inspecting and repairing the components in the fuel tank.

In the present invention of claim 2, since the lid portion is formed integrally with the inspection opening portion, the lid portion can be formed at the same time when the upper shell portion or the lower shell portion is molded, and manufacturing is easy. The inspection opening can be completely closed. Further, since the parts in the fuel tank are formed so that they can be cut at the time of inspection and repair, the inspection opening can be easily opened, and inspection and repair can be easily performed.

The present invention of claim 3 is the fuel tank in which the lid portion is formed separately from the inspection opening and is screwed to the inspection opening screw portion.

In the present invention of claim 3, since the lid is formed separately from the inspection opening and is screwed to the inspection opening screw portion, the lid is easily removed at the time of inspection and repair of parts inside the fuel tank. be able to.

According to a fourth aspect of the present invention, the outer sheet layer is a fuel tank formed of a fuel permeation-resistant multilayer resin sheet.

In the present invention of claim 4, since the outer sheet layer is formed of a fuel permeation-resistant multilayer resin sheet, it is possible to prevent permeation of fuel oil inside the fuel tank. Because it is a multilayer sheet, a layer with good adhesion to the inner resin layer is formed on the surface facing the inner resin layer of the upper shell portion and the lower shell portion of the fuel permeation resistant layer in the multilayer sheet, and wear resistance on the outside And impact resistant layers can be formed.

According to the fifth aspect of the present invention, when the stepped portion is formed around the inspection opening portion and lower than the outer wall surface of the upper shell portion or the lower shell portion, and the lid portion is separated, the outer sheet layer is applied to the stepped portion. The fuel tank is formed so that the seal member of the opening / closing lid can be brought into contact with or joined to the outer sheet layer of the stepped portion.

In the present invention of claim 5, since the step portion that is lower than the outer wall surface of the upper shell portion or the lower shell portion is formed around the inspection opening portion, the position of the lid portion of the inspection opening portion becomes clear, and the inspection opening portion The opening of the opening / closing lid can be held by the stepped portion after opening.
When the lid portion was separated, the outer sheet layer was in contact with or joined to the step portion, and the seal member for the opening / closing lid was formed on the stepped outer sheet layer. For this reason, when closing the inspection opening with the opening opening / closing lid after opening the inspection opening, the outer sheet layer abuts or joins the periphery of the inspection opening, and the seal member abuts on the outer opening layer. Fuel permeation resistance can be ensured.

According to the sixth aspect of the present invention, the lid portion of the inspection opening portion is formed with a flange portion that contacts the step portion of the inspection opening portion when the lid portion of the inspection opening portion is screwed to the inspection opening portion screw portion. The lid part that is formed separately from the part and screwed to the screw part of the inspection opening is not bonded or welded, and the outer sheet layer corresponds to the step part when the inspection part is opened by removing the cover part. When the lid is screwed to the inspection opening screw part after the inspection opening is opened, the outer sheet layer of the part corresponding to the step part is pressed by the lid part. It is a fuel tank which contacts.

In the present invention of claim 6, since the lid portion of the inspection opening is formed with a flange portion that comes into contact with the step portion of the inspection opening when screwed to the inspection opening screw portion, the inspection opening is The lid can be removed when opening, and the lid can be used as it is as an opening / closing lid.
The outer sheet layer is formed separately from the inspection opening and is screwed to the inspection opening screw portion. The outer sheet layer is not bonded or welded, and is removed when the inspection opening is opened by removing the lid. The sheet layer is excised leaving a portion corresponding to the stepped portion, and when the lid is screwed to the inspection opening screw portion after the inspection opening is opened, the outer sheet layer of the portion corresponding to the stepped portion is the lid. Is pressed by the portion and abuts on the stepped portion. For this reason, after the inspection opening is opened, when the lid is screwed to the inspection opening screw portion, the outer sheet layer is in close contact with the stepped portion, a sealing member is placed on the step portion, and the flange portion is attached to the sealing member. The outer sheet layer can be pressed and the fuel permeation resistance of the inspection opening can be ensured.

According to the seventh aspect of the present invention, each joint peripheral edge portion of the upper shell portion and the lower shell portion is formed with a flange portion projecting outward at a substantially right angle over the entire circumference, and the outer sheet layer covers the tip of the flange portion. Fuel tank.

According to the present invention of claim 7, each joint peripheral edge portion of the upper shell portion and the lower shell portion is formed with a flange portion projecting outward at a substantially right angle over the entire circumference, and the outer sheet layer is covered to the tip of the flange portion. did. Therefore, the flange portions of the upper shell portion and the lower shell portion are pressure-bonded to each other, so that the joining peripheral edge portions of the upper shell portion and the lower shell portion can be firmly adhered and fixed over the entire circumference. Further, fuel permeation from the joining peripheral edge portion and the flange portion can be prevented.

The present invention of claim 8 is the fuel tank in which the upper shell portion and the lower shell portion are formed of an inner resin layer of high-density polyethylene (HDPE) and an outer sheet layer of a fuel-permeable multilayer resin sheet.

In the present invention of claim 8, in the upper shell portion and the lower shell portion, the inner resin layer is formed of high-density polyethylene (HDPE), and the outer sheet layer is formed of a fuel-permeable multilayer resin sheet. For this reason, since the inner resin layers of the upper shell portion and the lower shell portion are formed of high density polyethylene (HDPE), the strength of the fuel tank can be increased.

Since the outer sheet layer is formed of a fuel permeation-resistant multilayer resin sheet, it is possible to prevent permeation of the fuel oil when the fuel oil is put inside the fuel tank. Because it is a multilayer sheet, high-density polyethylene (HDPE) and a layer with good adhesion are formed on the surface of the fuel-permeable layer opposite to the upper shell portion and the inner resin layer of the lower shell portion, and the outer surface has high wear resistance and An impact resistant layer can be formed.

An inspection opening portion is provided in a part of the outer wall of the upper shell portion or the lower shell portion, and the outer sheet layer covers the lid portion of the inspection opening portion. For this reason, until the inspection opening is opened, the inspection opening can be completely blocked, and fuel can be prevented from permeating through the inspection opening.
The lid portion is formed so as to be separable, and when the lid portion is separated, an inspection opening screw portion to which an opening opening / closing lid that closes the inspection opening portion can be attached is formed. The lid can be easily separated and removed when checking the parts. In addition, after the inspection and repair are completed, the opening opening / closing lid that closes the inspection opening can be screwed to the inspection opening screw.

The embodiment of the present invention will be described with reference to FIGS. 1 to 17 by taking a fuel tank 1 for an automobile as an example. The present invention can be used for various fuel tanks besides those for automobiles.
FIG. 1 is a longitudinal sectional view of the fuel tank 1, and FIG. 2 is a schematic diagram showing a process of welding the joining peripheral portions 11 and 21 of the upper shell portion 10 and the lower shell portion 20 of the fuel tank 1.
3-17 is a figure which shows the manufacturing method of the inspection opening part 13 of the fuel tank 1. FIG.

The fuel tank 1 includes an upper shell portion 10 and a lower shell portion 20 that are separately formed. The upper shell portion 10 and the lower shell portion 20 are each composed of inner resin layers 15 and 25 formed by injection molding, and a fuel-permeable multilayer resin sheet 3 formed outside the inner resin layers 15 and 25, respectively. The outer sheet layers 16 and 26 are formed from two layers.
The fuel tank 1 can be divided into not only two but also three or more.
In this embodiment, the fuel tank 1 having the fuel pump unit 4 attached to the lower shell portion 20 and the inspection opening 13 provided in the upper shell portion 10 will be described as an example.

  On the inner surfaces of the upper shell portion 10 and the lower shell portion 20, a plurality of inner ribs 17 and 27 can be integrally formed toward the inner direction of the fuel tank 1. The inner ribs 17 and 27 increase the strength and rigidity of the fuel tank 1. It is also possible to integrally mold the mounting structure inside the tank shell. A fuel pump unit 4 installed in the fuel tank 1, a canister, a valve, a hose, and the like can be attached.

  In the upper shell portion 10, a pipe mounting hole 2 and an inspection opening portion 13 of the pump unit are formed. The inspection opening 13 of the pump unit is a hole for inspecting and repairing the fuel pump unit 4 mounted inside the fuel tank 1, and the pipe mounting hole 2 is a pipe for fuel injection (not shown). It is a hole to install. A hose clamp (not shown) for holding various hoses such as a fuel transfer hose may be provided on the upper surface of the upper shell portion 10.

As shown in FIG. 2, a joint peripheral edge 11 of the upper shell 10 and a joint peripheral 21 of the lower shell 20 are formed on the entire periphery of the opening of the upper shell 10 and the lower shell 20. , 21 are formed with flange portions 12, 22 projecting outward from the outer surface over the entire circumference. The joining peripheral edge parts 11 and 21 and the flange parts 12 and 22 are welded so as to face each other.
As shown in FIG. 2, the flange portions 12 and 22 are formed so that the upper shell portion 10 and the main body of the lower shell portion 20 have a substantially L-shaped cross section.

The outer surfaces of the inner resin layers 15 and 25 of the upper shell portion 10 and the lower shell portion 20 are entirely welded to the front ends of the flange portions 12 and 22, and the fuel-permeable multilayer resin sheet 3 is integrally welded. The outer sheet layers 16 and 26 are configured. The fusion of the fuel-permeable multilayer resin sheet 3 can be performed by heating the surface of the fuel-permeable multilayer resin sheet 3. For this reason, fuel permeation can be prevented up to the tips of the flange portions 12 and 22.

The fuel permeation-resistant multilayer resin sheet 3 is formed of, for example, a barrier layer for preventing fuel permeation in which a central layer is formed of ethylene vinyl alcohol copolymer (EVOH) or nylon, and modified polyethylene above and below the barrier layer. It is a 5 layer sheet | seat comprised from the outer layer formed from the adhesive layer made and polyethylene (PE) on the outer surface of the adhesive layer.

The adhesive layer formed from the modified polyethylene has adhesion to both the barrier layer and the outer layer. For this reason, a barrier layer and an outer layer can be adhered firmly.
The outer layer of the fuel permeation-resistant multilayer resin sheet 3 can be formed of polyethylene (PE) that is resistant to impact and abrasion, in which case the strength of the fuel tank 1 is increased and the barrier layer is protected. Can do. The inner resin layers 15 and 25 are bonded to the inner resin layers 15 and 25 when the inner resin layers 15 and 25 are made of an olefin-based synthetic resin, for example, high-density polyethylene (HDPE). And can be firmly joined.

An inspection opening 13 for inspecting the fuel pump unit 4 and the like is formed in the inner resin layer 15 of the upper shell portion 10 as will be described in detail later. The inspection opening 13 is covered with an outer sheet layer 16 that is a fuel-permeable multilayer resin sheet 3 whose outer side is continuous with other parts of the upper shell portion 10. For this reason, permeation | transmission of a fuel can also be prevented also about the inspection opening part 13 part like other parts.

Next, a method for welding the joining peripheral edge portions 11 and 21 of the upper shell portion 10 and the lower shell portion 20 will be described. First, components such as the fuel pump unit 4 mounted in the fuel tank 1 are attached to the upper shell portion 10 and the lower shell portion 20.
Thereafter, as shown in FIG. 2, the joining peripheral portions 11 and 21 of the upper shell portion 10 and the lower shell portion 20 are opposed to each other with a gap therebetween, and a hot plate 30 is placed between them, so that the joining peripheral portions 11 and 21 are placed on the entire circumference. Heat over. Thereby, the part which the joining peripheral parts 11 and 21 and the flange parts 12 and 22 oppose can be softened.

Next, the flange parts 12 and 22 of the joining peripheral edge parts 11 and 21 of the upper shell part 10 and the lower shell part 20 are each pressed and welded with a holding jig. At this time, if the outer sheet layers 16 and 26 at the tips of the flange portions 12 and 22 are pressed and thinned, the permeation of fuel from the flange portions 12 and 22 can be prevented.

Next, the inspection opening 13 is opened when the structure and manufacturing method of the inspection opening 13 and the fuel pump unit 4 according to the first embodiment of the present invention are inspected and repaired, and the opening is opened and closed by the opening / closing lid 50. Will be described with reference to FIGS.
The inspection opening 13 is formed with a stepped portion 13b slightly lowered from the outer wall surface of the upper shell portion 10 in the periphery. A lid portion 13a is formed integrally with the step portion 13b so as to block the opening portion of the inspection opening portion 13. A groove 13c is formed at the boundary between the step 13b and the lid 13a. An inspection opening screw part 14 having a thread formed on the inner surface is formed in a cylindrical shape downward (inward direction of the tank) from the step part 13b.

The step portion 13b, the lid portion 13a, the groove portion 13c, and the inspection opening portion screw portion 14 can be simultaneously formed when the upper shell portion 10 is injection-molded.
Thereafter, as shown in FIG. 4, the fuel-permeable multilayer resin sheet 3 is bonded or welded to the outer surface to form the outer sheet layer 16. Thereby, the fuel permeation resistance of the inspection opening 13 can be ensured.
Thus, the manufacture of the fuel tank 1 is completed and can be mounted on an automobile or the like.

Next, when the fuel pump unit 4 or the like needs to be inspected or repaired after the fuel tank 1 is mounted on an automobile or the like, the cutting blade 60 is inserted into the groove 13c of the inspection opening 13 as shown in FIG. The lid portion 13a and the outer sheet layer 16 thereon are simultaneously cut and removed by applying and rotating. If it does so, the inspection opening part 13 will open, and it can inspect or repair. The outer sheet layer 16 remains adhered to the step 13b of the inspection opening 13.

When the inspection or repair is completed, as shown in FIG. 6, the opening opening / closing lid 50 is fitted into the inspection opening 13 to close it.
The opening / closing lid 50 includes a ceiling 51 that closes the inspection opening 13, and a screw portion 52 that has a thread formed on the outer surface downward from the lower surface around the ceiling portion. A lid flange portion 53 that protrudes in the direction is formed. The opening / closing lid 50 is made of a fuel-permeable material.

When the opening portion opening / closing lid 50 is fitted into the inspection opening portion 13, a seal ring 54 as a seal member is attached under the lid flange portion 53. The seal ring 54 is in contact with the stepped portion 13b of the inspection opening 13 and can be stably held and sealed without the seal ring 54 coming off. The outer sheet layer 16 is bonded to the stepped portion 13 b, and the fuel permeation resistance of the inspection opening 13 can be ensured by the seal ring 54 and the opening opening / closing lid 50.

Next, the structure and manufacturing method of the inspection opening 13 and the method of opening the inspection opening 13 when inspecting and repairing the fuel pump unit 4 according to the second embodiment of the present invention will be described with reference to FIGS. explain. The method of closing the inspection opening 13 with the opening opening / closing lid 50 after opening the inspection opening 13 is the same as in the first embodiment, and the description thereof is omitted.

The inspection opening 13 is formed with a stepped portion 13b slightly lowered from the outer wall surface of the upper shell portion 10 in the periphery. An inspection opening screw portion 14 having a thread formed on the inner surface is formed in a cylindrical shape continuously from the inner resin layer 15 downward from the step portion 13b (inner direction of the tank).
An inspection opening closing member 18 formed separately from the upper shell portion 10 is screwed to the inspection opening screw portion 14. The inspection opening closing member 18 forms a ceiling 18a having a flat upper surface. A cylindrical portion 18d is formed downward from the periphery of the ceiling portion 18a, and a screw thread is formed on the outer periphery of the cylindrical portion 18d. For this reason, it can be screwed to the inspection opening screw part 14 of the inspection opening 13.

On the inspection opening closing member 18, the fuel-permeable multilayer resin sheet 3 is continuously bonded or welded from the upper shell portion 10, as in the first embodiment. And as shown in FIG. 8, it becomes the outer sheet | seat layer 16, By this, the fuel-permeation resistance of the inspection opening part 13 is securable. In addition, since the groove-shaped recessed part is formed between the inspection opening part closing member 18 and the step part 13b of the inspection opening part 13, the position of the inspection opening part closing member 18 can be confirmed.
Thus, the manufacture of the fuel tank 1 is completed and can be mounted on an automobile or the like.

Next, when the fuel pump unit 4 or the like needs to be inspected or repaired after being mounted on an automobile or the like, the cutting blade 60 is applied to the groove portion 13c of the inspection opening 13 as in the first embodiment. Rotate to cut out outer sheet layer 16 and rotate inspection opening closure member 18 to remove. If it does so, the inspection opening part 13 will open, and it can inspect or repair. After that, attaching the opening / closing lid 50 is the same as in the first embodiment.

Since the inspection opening closing member 18 is screwed to the inspection opening screw portion 14, the inspection opening closing member 18 can be easily removed.
In the second embodiment, since the inspection opening closing member 18 is screwed, only the outer sheet layer 16 needs to be cut, and the inspection opening closing member 18 can be easily removed.

Next, the structure and manufacturing method of the inspection opening 13 and the method of opening the inspection opening 13 when inspecting and repairing the fuel pump unit 4 according to the third embodiment of the present invention will be described with reference to FIGS. explain.
The shape of the inspection opening portion 13 is the same as that of the second embodiment, and a step portion 13b slightly lowered from the outer wall surface of the upper shell portion 10 is formed in the periphery. An inspection opening screw portion 14 having a thread formed on the inner surface is formed in a cylindrical shape continuously from the inner resin layer 15 downward from the step portion 13b (inner direction of the tank).

An opening opening / closing lid 50 formed separately from the upper shell portion 10 is screwed to the inspection opening screw portion 14. Similarly to the second embodiment, after opening the inspection opening 13, the opening opening / closing lid 50 that closes the inspection opening 13 is screwed in advance. On the lower surface of the opening / closing lid 50, there is formed a screw part 52 having a cylindrical shape and a thread formed on the outer periphery, and the screw part 52 can be screwed to the inspection opening screw part 14.

The fuel permeation-resistant multilayer resin sheet 3 is continuously in contact with the upper shell portion 10 on the ceiling portion 51 above the opening opening / closing lid 50. This fuel-permeable multilayer resin sheet 3 is neither bonded nor welded to the opening / closing lid 50. At this time, the ceiling 51 of the upper part of the opening / closing lid 50 protrudes from the upper surface of the upper shell part 10. Therefore, the position of the opening / closing lid 50 can be confirmed.
Thus, the manufacture of the fuel tank 1 is completed and can be mounted on an automobile or the like.

Next, when the fuel pump unit 4 or the like needs to be inspected or repaired after being mounted on an automobile or the like, as will be described later, inside the opening / closing lid 50 of the inspection opening 13 as shown in FIG. Thus, leaving the width | variety which the edge part of the outer side sheet layer 16 can contact | abut of the step part 13b, the cutting blade 60 is applied and rotated, and the outer side sheet layer 16 on it is cut off and removed. Since the outer sheet layer 16 is not bonded to the opening opening / closing lid 50, it can be easily removed. And as shown in FIG. 11, it can remove by opening 50 opening-and-closing lids. If it does so, the inspection opening part 13 will open, and it can inspect or repair.

When the inspection or repair is completed, as shown in FIGS. 12 and 13, the opening opening / closing lid 50 is fitted and closed in the inspection opening 13.
First, as shown in FIG. 12, a seal ring 54 is fitted as a seal portion on the lower surface of the lid flange portion 53 of the removed opening / closing lid 50.
Thereafter, as shown in FIG. 13, the uncut end portion of the outer sheet layer 16 is pressed against the step portion 13 b of the inspection opening portion 13 portion.

Then, the opening / closing lid 50 is fitted into the inspection opening 13. If it does so, the seal ring 54 can contact | abut to the outer sheet | seat layer 16 in the step part 13b of the inspection opening part 13, and can seal between the outer sheet | seat layer 16 and the seal ring 54, and fuel-proof permeability is ensured. be able to. Further, the step portion 13b can stably hold the seal ring 54 without detachment.
The opening / closing lid 50 is made of a material that prevents fuel permeation.

Next, the structure and manufacturing method of the inspection opening 13 and the method of opening the inspection opening 13 when inspecting and repairing the fuel pump unit 4 according to the fourth embodiment of the present invention will be described with reference to FIGS. explain.
As shown in FIG. 14, the shapes of the inspection opening 13 and the opening opening / closing lid 50 are the same. The opening / closing lid 50 is screwed, and the fuel-permeable multilayer resin sheet 3 is continuously in contact with the upper shell portion 10 on the ceiling portion 51 above the opening / closing lid 50. Is the same. Moreover, it is the same until the manufacture of the fuel tank 1 is completed. That is, the fuel permeation-resistant multilayer resin sheet 3 is not bonded or welded to the opening / closing lid 50, and the ceiling 51 of the upper portion of the opening / closing lid 50 protrudes from the upper surface of the upper shell portion 10. The same is true.

However, there is a difference when the fuel pump unit 4 or the like needs to be inspected or repaired after being mounted on an automobile or the like.
As shown in FIG. 15, at the boundary between the opening opening / closing lid 50 and the inspection opening 13 of the inspection opening 13, the outer sheet layer 16 is cut off by rotating the outer sheet layer 16 against the cutting blade 60. ,remove. Since the outer sheet layer 16 is not bonded to the opening opening / closing lid 50, it can be easily removed. And as shown in FIG. 16, it can remove by opening 50 opening-and-closing lid | covers. If it does so, the inspection opening part 13 will open, and it can inspect or repair.

When the inspection or repair is completed, as shown in FIGS. 17 and 18, the opening opening / closing lid 50 is fitted into the inspection opening 13 to close it.
First, as shown in FIG. 17, a gasket 55 is fitted as a seal portion on the lower surface of the lid flange portion 53 of the opened opening / closing lid 50.
Thereafter, as shown in FIG. 18, the opening opening / closing lid 50 is screwed so that the gasket 55 can be pressed against the end portion of the outer sheet layer 16 and the step portion 13 b of the inspection opening portion 13.

Then, the opening / closing lid 50 is fitted into the inspection opening 13. Then, the gasket 55 can contact the end portion of the outer sheet layer 16 and the stepped portion 13b of the inspection opening 13, and can be sealed between the outer sheet layer 16 and the gasket 55 to ensure fuel permeation resistance. be able to. In particular, since the gasket 55 is press-contacted by the flange portion 53 so as to cover the end portion of the outer sheet layer 16, the gasket 55 can be stably removed by the lid flange portion 53 and the step portion 13 b of the opening opening / closing lid 50. Can be retained.
The opening / closing lid 50 is similarly formed of a material that prevents fuel permeation.

It is sectional drawing of the longitudinal direction of the fuel tank which is embodiment of this invention. It is a cross-sectional schematic diagram of the state which fuse | melts the joining peripheral part of the upper shell part and lower shell part of a fuel tank which is embodiment of this invention with a hot platen. It is a cross-sectional schematic diagram which shows the manufacturing process of the inspection opening part which is the 1st Embodiment of this invention, and is a cross-sectional schematic diagram which shows the process of the part which fuse | melts a fuel-permeable multilayer resin sheet to an inspection opening part. is there. It is sectional drawing which shows the state which fused the fuel-permeable multilayer resin sheet to the inspection opening which is the 1st Embodiment of this invention. It is a cross-sectional schematic diagram which shows the opening process of the inspection opening part which is the 1st Embodiment of this invention. It is sectional drawing which shows the state which closed the inspection opening part with the opening part opening-and-closing lid | cover after opening of the inspection opening part which is the 1st Embodiment of this invention. It is a cross-sectional schematic diagram which shows the manufacturing process of the inspection opening which is the 2nd Embodiment of this invention, and is a cross-sectional schematic diagram which shows the process of the part which fuse | melts a fuel-permeable multilayer resin sheet to an inspection opening. is there. It is sectional drawing which shows the state which fused the fuel-permeable multilayer resin sheet to the inspection opening which is the 2nd Embodiment of this invention. It is sectional drawing which shows the state which fused the fuel-permeable multilayer resin sheet to the inspection opening which is the 3rd Embodiment of this invention. It is a cross-sectional schematic diagram which shows the process of excising an outer sheet | seat layer in the opening process of the inspection opening part which is the 3rd Embodiment of this invention. It is a cross-sectional schematic diagram which shows the process of removing an opening part opening-and-closing lid in the opening process of an inspection opening part which is the 3rd Embodiment of this invention. It is a cross-sectional schematic diagram which shows the process which removed the opening part opening-and-closing lid | cover and attached the seal ring in the opening process of the inspection opening part which is the 3rd Embodiment of this invention. It is sectional drawing which shows the state which closed the inspection opening part with the opening part opening-and-closing lid | cover after opening of the inspection opening part which is the 3rd Embodiment of this invention. It is sectional drawing which shows the state which fused the fuel-permeable multilayer resin sheet to the inspection opening which is the 4th Embodiment of this invention. It is a cross-sectional schematic diagram which shows the process of excising an outer sheet | seat layer in the opening process of the inspection opening part which is the 4th Embodiment of this invention. It is a cross-sectional schematic diagram which shows the process of removing an opening part opening-and-closing lid in the opening process of an inspection opening part which is the 4th Embodiment of this invention. In the opening process of the inspection opening part which is the 4th Embodiment of this invention, it is a cross-sectional schematic diagram which shows the process which removed the opening part opening-and-closing cover and attached the seal gasket. It is sectional drawing which shows the state which closed the inspection opening part with the opening part opening-and-closing lid | cover after opening of the inspection opening part which is the 4th Embodiment of this invention. It is a schematic diagram which shows the state which welded the conventional upper shell part and the lower shell part. It is sectional drawing of the conventional fuel tank.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel tank 10 Upper shell part 13 Inspection opening part 15, 25 Inner resin layer 16, 26 Outer sheet layer 18 Inspection opening closing member 20 Lower shell part 50 Opening part opening / closing cover

Claims (8)

In a fuel tank made of thermoplastic synthetic resin,
The fuel tank is integrally formed by fusing the joint peripheral portions of the upper shell portion and the lower shell portion, which are separately molded by injection molding, respectively, and the upper shell portion and the lower shell portion are respectively formed on the inner resin layer. And an outer sheet layer covering the outer surface of the inner resin layer,
An inspection opening for parts in the fuel tank is provided in a part of the outer wall of the upper shell portion or the lower shell portion, the inspection opening portion is closed by a lid portion, the outer sheet layer covers the lid portion, and the lid The part is formed so as to be separable together with the outer sheet layer at the time of inspecting the components in the fuel tank, and when the lid is separated from the inner resin layer of the inspection opening, the inspection opening A fuel tank, characterized in that an inspection opening screw portion to which an opening opening / closing lid for closing the opening is attachable is formed. 2. The fuel tank according to claim 1, wherein the lid is formed integrally with the inspection opening, and is formed so as to be capable of being cut when inspecting and repairing components in the fuel tank. The fuel tank according to claim 1, wherein the lid is formed separately from the inspection opening and is screwed to the inspection opening screw portion. The fuel tank according to any one of claims 1 to 3, wherein the outer sheet layer is formed of a fuel permeation-resistant multilayer resin sheet. A stepped portion lower than the outer wall surface of the upper shell portion or the lower shell portion is formed around the inspection opening portion, and when the lid portion is separated, the outer sheet layer contacts or joins the stepped portion. The fuel tank according to any one of claims 1 to 4, wherein a seal member for the opening / closing lid is formed on the outer sheet layer of the stepped portion so as to be in contact therewith. The lid portion of the inspection opening is formed with a flange portion that abuts on the step portion of the inspection opening when screwed to the inspection opening screw portion, and the outer sheet layer is separated from the inspection opening. The outer sheet layer corresponds to the stepped portion when the inspection opening is opened by removing the lid and not being bonded to the lid that is formed and screwed to the inspection opening screw. When the lid is screwed to the inspection opening screw part after the inspection opening is opened, the outer sheet layer of the part corresponding to the stepped part is formed on the lid part. The fuel tank according to claim 5, wherein the fuel tank is pressed and contacts the stepped portion. 7. The joining peripheral edge portion of each of the upper shell portion and the lower shell portion is formed with a flange portion that protrudes outward over the entire circumference, and the outer sheet layer covers the tip of the flange portion. The fuel tank according to any one of the above. 8. The upper shell portion and the lower shell portion according to claim 1, wherein the inner resin layer is formed of high density polyethylene (HDPE), and the outer sheet layer is formed of a fuel-permeable multilayer resin sheet. The fuel tank according to item 1.

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