JP2009001048A - Fuel tank structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a fuel tank structure which achieves an improvement in heat insulating properties with a simple structure. <P>SOLUTION: The fuel tank structure is applied to a vehicular fuel tank 10. The vehicular fuel tank has the following configuration. A fuel tank body 12 is configured that at least the outer shell 16 forming the outermost layer is composed of a resin material. The fuel tank body is covered with a covering material 20 fixed onto the outer surface 16A of the outer shell 16 by welding. The covering material 20 is composed of knitting 25 made of hollow fibers. Therefore, a heat insulating layer is formed on the outside of the tank body 12. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel tank structure for storing a fuel containing, for example, a hydrocarbon liquid.

A technique is known in which a foam layer having high heat insulating properties is provided on the outer surface of the lower part of a resin tank via a nonwoven fabric layer (see, for example, Patent Document 1).
JP 7-68630 A

  However, in the conventional technology as described above, since the nonwoven fabric is interposed between the tank and the foamed layer, the structure and the manufacturing method are complicated.

  In view of the above facts, an object of the present invention is to obtain a fuel tank structure that can improve heat insulation with a simple structure.

  In the fuel tank structure according to the first aspect of the invention, at least the outer surface of the fuel tank main body, the outermost layer of which is made of a resin material, is covered with a covering material made of resin hollow fibers.

  In the fuel tank structure according to the first aspect, the heat insulating layer is formed by the hollow fibers of the resin constituting the covering material covering the tank body, that is, the internal spaces of the hollow fibers. Thereby, the heat insulation of a tank main body improves compared with the structure which does not provide a coating | covering material. And since each of the outermost layer which comprises the outer surface of a tank main body, and the hollow fiber which comprises a coating | covering material is comprised with the resin material, it is a simple structure which joins these directly (for example, adhesion | attachment, welding, etc.). Good bonding strength can be obtained.

  Thus, in the fuel tank structure according to the first aspect, the heat insulation can be improved with a simple structure.

  A fuel tank structure according to a second aspect of the present invention is the fuel tank structure according to the first aspect, wherein the covering material is welded to the outer surface of the fuel tank body.

  In the fuel tank structure according to the second aspect, since the covering material is directly fixed to the tank body by welding, the bonding strength between the tank and the covering material is increased, and the reliability is improved.

  A fuel tank structure according to a third aspect of the present invention is the fuel tank structure according to the first or second aspect, wherein the hollow fiber and the outermost layer of the tank body are made of the same kind of resin material. .

  In the fuel tank structure according to the third aspect, since the outermost layer of the tank body and the hollow fiber of the covering material to be joined to each other are made of the same kind of resin material, it is easy to further improve the joining strength.

  The fuel tank structure according to a fourth aspect of the present invention is the fuel tank structure according to any one of the first to third aspects, wherein the covering material is a string-like body in which the hollow fibers are bundled and fixed. It is formed as a knitted fabric.

  In the fuel tank structure according to the fourth aspect, since the covering material is formed of a string-like knitted fabric in which hollow fibers are bundled, a plurality of heat insulating layers are formed on the outside of the tank body, and the heat insulating effect is high. Moreover, since the hollow fibers of the string-like body are fixed to each other, the heat insulating effect is improved. In addition, for example, the number of hollow fibers constituting the string-like body and the number of layers of the plurality of heat insulating layers can be adjusted by adjusting the number of layers of the knitted fabric, and the required heat insulating performance can be obtained with a simple structure. it can.

  The fuel tank structure according to a fifth aspect of the present invention is the fuel tank structure according to any one of the first to fourth aspects, wherein an end of the hollow fiber is closed at a peripheral edge of the covering material. .

  In the fuel tank structure according to claim 5, since the end portion of the hollow fiber is closed at the peripheral portion of the covering material, air circulation in the hollow fiber is prevented or remarkably suppressed, and the heat insulating effect by the covering material (heat insulating layer). Will improve.

  A fuel tank structure according to a sixth aspect of the present invention is the fuel tank structure according to the fifth aspect, wherein the outer surface of the tank is covered with different portions by the plurality of coating materials, and the plurality of coating materials The end of the hollow fiber is closed at the connecting portion.

  In the fuel tank structure according to the sixth aspect, the tank main body is covered with a plurality of covering materials, and the ends of the hollow fibers are closed at the connecting portions (joining portions) of the plurality of covering materials. As a result, in a configuration in which a wide range (for example, substantially the entire circumference) of the tank body is covered with a plurality of covering materials, air circulation in the hollow fibers is prevented or remarkably suppressed, and the heat insulating effect by the covering material (heat insulating layer) is improved. To do.

  As described above, the fuel tank structure according to the present invention has an excellent effect that heat insulation can be improved with a simple structure.

  A vehicle fuel tank 10 to which a fuel tank structure according to an embodiment of the present invention is applied will be described with reference to FIGS. 1 to 8.

  FIG. 1 is a schematic side view in which a vehicle fuel tank 10 is partially cut away. As shown in this figure, the vehicle fuel tank 10 includes a tank body 12. The tank body 12 is configured to store gasoline as fuel injected from a fuel injection port (not shown), and is mainly composed of a resin material.

  Specifically, as shown in FIG. 2 which is an enlarged view of “2” in FIG. 1, the tank body 12 is a resin tank having a multi-layer structure, and at least an inner shell 14 as an inner layer and an outer layer as an inner layer. An outer shell 16, a barrier layer 18 as a fuel permeation preventive layer disposed between the inner shell 14 and the outer shell 16, and an adhesive layer (not shown) for joining the barrier layer 18 to the inner shell 14 and the outer shell 16. It is configured to include.

  Each of the inner shell 14 and the outer shell 16 is made of a resin material such as high density polyethylene (HDPE). The outer shell 16 forms an outermost layer having the outer surface of the tank body 12. The barrier layer 18 is made of a resin material such as ethylene-vinyl alcohol copolymer (EVOH). The barrier layer 18 is bonded to the inner shell 14 and the outer shell 16 with an adhesive layer made of a resin material such as modified polyethylene having adhesiveness.

  The outer surface of the tank body 12 described above is covered with the covering material 20. In this embodiment, as shown in FIG. 1, the tank body 12 is covered with a covering material 20 over substantially the entire circumference excluding a fuel injection port (not shown). Thereby, in the vehicle fuel tank 10, the heat insulating layer 22 is formed on the outer side of the tank body 12 over substantially the entire circumference. This will be specifically described below.

  As shown in FIGS. 4 and 5, the covering material 20 is configured using a knitted fabric 25 of a string-like body 24. The string-like body 24 is configured as a flexible long member configured by bundling a plurality of fibers 26. The plurality of fibers 26 constituting the string-like body 24 are made of a resin material, are hollow fibers that are hollow bodies as shown in FIG. 6, and are formed in a long shape having flexibility. As shown in FIG. 7, the string-like body 24 is configured by fixing a plurality of fibers 26 (adjacent fibers 26) bundled as described above by welding, and each fiber 26 is not unraveled. It is configured.

  As shown in FIG. 1, the covering material 20 includes an upper half 20 </ b> A that covers the upper part of the tank body 12 and a lower half 20 </ b> B that covers the lower part of the tank body 12. The upper half 20 </ b> A and the lower half 20 </ b> B are formed in a container shape that opens to the joint side by molding a knitted fabric 25 as shown in FIGS. 4 and 5. Thereby, the covering material 20 is stored in the tank half 12 so as not to fall off by accommodating the tank body 12 in the upper half 20A and the lower half 20B and joining the open ends of the upper half 20A and the lower half 20B. The main body 12 is covered.

  In this embodiment, in the covering state, the covering material 20 has the inner surfaces (fibers 26) of the upper half 20A and the lower half 20B in close contact with the tank body 12, that is, the outer surface 16A of the outer shell 16. Further, in this embodiment, the inner surfaces 20C (fibers 26) of the upper half 20A and the lower half 20B are fixed to the outer surface 16A of the outer shell 16 of the tank body 12 by welding.

  As described above, the heat insulating layer 22 on the outside of the tank body 12 in the vehicle fuel tank 10 is constituted by an air layer in the fibers 26 constituting the covering material 20. In this embodiment, as shown in FIG. 3, the joint flange portion 20D of the upper half 20A and the lower half 20B from which the ends of the plurality of fibers 26 are exposed is compression-welded (crushed), and the plurality of fibers The end of 26 is closed. Thereby, the air layer in each fiber 26 which comprises the heat insulation layer 22 of the outer side of the tank main body 12 is comprised as a heat insulation air layer without the inflow / outflow (convection) of air (suppressed). The joining flange portion 20D corresponds to the joining portion of the covering material in the present invention.

  Each fiber 26 constituting the covering material 20 described above is made of a resin material as described above. In this embodiment, the fiber 26 is made of the same kind of resin material as the resin material constituting the outer shell 16. . In this embodiment, both the outer shell 16 and each fiber 26 are made of HDPE.

  Next, the operation of this embodiment will be described.

  In manufacturing the vehicle fuel tank 10 having the above-described configuration, first, the tank body 12 is molded by blow molding or the like, and the upper half 20A and the lower half 20B are molded. That is, a knitted fabric 25 composed of a string-like body 24 in which a plurality of fibers 26 are bundled is prepared, and the upper half 20A and the lower half 20B are molded with the knitted fabric 25. At this time, as shown in FIG. 8, a joining flange portion 20D is stretched and formed at the opening ends of the upper half 20A and the lower half 20B.

  Next, substantially the entire inner surface 20C of the upper half 20A and the lower half 20B is heated with a hot plate (not shown), and substantially the entire outer surface 16A of the outer shell 16 of the tank body 12 is heated with a hot plate (not shown). Then, as shown in FIG. 8, the upper half 20 </ b> A and the lower half 20 </ b> B are placed on the tank body 12 and pressed against the tank body 12 (a compression load is applied). At this time, the tank body 12 may be filled with gas or the like to apply an internal pressure. In FIG. 8, only the upper half 20A and the lower half 20B are shown in a sectional view.

  As described above, the upper half 20A and the lower half 20B (the inner surface 20C thereof) are welded (heat-sealed) to the tank body 12 (the outer surface 16A thereof). Next, the joining flange portions 20D that are abutted against each other in the upper half 20A and the lower half 20B are sandwiched in a vertical direction by a taper mold (jig) (not shown), and a compressive load is applied while heating. Accordingly, as shown in FIGS. 1 and 3, the upper and lower joining flange portions 20 </ b> D are compression-welded in a tapered shape so that the plate thickness is reduced on the outer peripheral side, and the ends of the plurality of fibers 26 constituting the covering material 20 ( The portions that were open ends) are closed.

  Thus, the manufacture of the vehicle fuel tank 10 in which the heat insulating layer 22 is formed on the outer side of the tank body 12 with the covering material 20 is completed.

  Thus, in the vehicle fuel tank 10 in which the heat insulating layer 22 is formed on the outside of the tank main body 12, heat transfer from the outside to the fuel (gasoline) in the tank main body 12 is suppressed. Compared with the tank body 12 that does not, the increase in the fuel temperature accompanying the increase in the outside air temperature and the generation amount of fuel vapor (vapor) can be suppressed. In particular, in the fuel tank 10 for vehicles, since the heat insulation layer 22 (covering material 20) is provided on the tank body 12 over substantially the entire surface excluding the fuel inlet and the like, the heat insulation effect is high.

  Accordingly, in an automobile to which the vehicle fuel tank 10 is applied, for example, a capacity of the canister for adsorbing the fuel vapor can be provided, and a long operation can be performed without depending on measures such as increasing the size of the canister. It is possible to prevent the fuel vapor from being released to the atmosphere when the engine is not operated for a time.

  Here, in the vehicular fuel tank 10, since the covering material 20 joined to the resin outer shell 16 in the tank main body 12 is made of resin hollow fibers 26, the heat insulating layer 22 is configured in the internal space of each fiber 26. The covering material 20 to be performed can be directly joined to the outer shell 16 with sufficient strength. In the vehicular fuel tank 10, the covering material 20 is directly joined to the outer shell 16. For example, an intermediate layer (for example, a nonwoven fabric in which fibers are not joined together) is interposed therebetween. Even if compared with these, the high joint strength of the tank main body 12 and the heat insulation layer 22 can be obtained. For this reason, the vehicle fuel tank 10 in which the heat insulating layer 22 is formed on the outside of the tank body 12 can be obtained with a simple structure.

  In the vehicular fuel tank 10, since the covering material 20 is welded (heat-sealed) to the outer shell 16 of the tank body 12, for example, a configuration in which an adhesive layer (adhesive or the like) is interposed therebetween (the present invention). The structure is simpler and easier to manufacture, and the manufacturing cost can be reduced. Further, the vehicle fuel tank 10 can be reduced in weight as compared with the configuration in which the intermediate layer and the adhesive layer are interposed between the covering material 20 and the tank body 12.

  In particular, in the vehicular fuel tank 10, the plurality of fibers 26 constituting the covering material 20 are made of the same resin material as the outer shell 16 (in this embodiment, HDPE). Bonding strength is high and reliability is improved. Moreover, since the covering material 20 joined to the tank body 12 with high joining strength is composed of the fibers 26 (particularly the knitted fabric 25), the effect of reinforcing the tank body 12 by the covering material 20 can be obtained. Thereby, in the fuel tank 10 for vehicles, the deformation | transformation of the tank main body 12 by an internal pressure (a negative pressure is included) can be suppressed, for example. That is, the pressure strength is improved.

  Further, in the vehicular fuel tank 10, since the covering material 20 uses the internal space of the plurality of fibers 26 as a heat insulating layer, the heat insulating performance is improved by the number of fibers 26 (the number of layers of the knitted fabric 25) in the thickness direction of the covering material 20. It is possible to adjust. Thus, the vehicle fuel tank 10 having appropriate heat insulation performance can be obtained in accordance with requirements (including the amount of fuel vapor generated, the capacity of the tank body 12, the outer dimensions of the vehicle fuel tank 10, etc.). .

  Furthermore, in the vehicle fuel tank 10, a plurality of fibers 26 are bundled and fixed to each other to form a string-like body 24, so that air can be prevented from entering and leaving the space between the plurality of fibers 26. The In particular, since the covering material 20 (the upper half 20A and the lower half 20B) is formed by the knitted fabric 25 using the string-like body 24, the relative displacement between the string-like bodies 24 (a plurality of fibers 26 constituting the string-like body 24) is suppressed. In addition, the entry and exit of air with respect to the space between the plurality of fibers 26 (strings 24) is effectively suppressed.

  In addition, since the vehicle fuel tank 10 has a structure in which the ends of the fibers 26 are closed, air does not enter and leave the internal spaces of the fibers 26. In particular, by forming the upper half 20A and the lower half 20B using the knitted fabric 25, the ends of the plurality of fibers 26 can be collected in the joining flange portion 20D that is the joining end of the upper half 20A and the lower half 20B. The structure which closes the terminal of the some fiber 26 which comprises this coating | covering material 20 can be implement | achieved, forming the coating | covering material 20 matched with 12 external shape.

  Accordingly, in the vehicular fuel tank 10, the heat insulating layer 22 having good heat insulating performance can be formed on the outer side of the tank body 12 by the covering material 20. Further, in the vehicular fuel tank 10, each fiber 26 of the covering material 20 has a structure that forms an internal space, that is, a heat insulating layer. Therefore, even if the surface side fiber 26 is broken due to wear or the like, the heat insulating performance is improved. The decrease is small. That is, the vehicle fuel tank 10 can maintain the required heat insulation performance by the covering material 20 over a long period of time.

  For example, in the configuration in which the heat insulating layer is formed of a foam material or the like, the heat insulating effect depends on the magnification (size, volume ratio) of the bubbles, so in order to improve the heat insulating performance, the volume occupancy of the bubbles becomes high, Low durability. Further, if the thickness of the foam material layer is increased in order to improve the heat insulation performance, it causes a restriction on the capacity, outer diameter size, and tank body thickness of the fuel tank. On the other hand, in the vehicular fuel tank 10, the covering material 20 using hollow fibers forms the heat insulating layer 22 having excellent heat insulating effect, durability and bonding strength as described above. There are few restrictions on the dimensions and the thickness of the tank body 12.

  In the above-described embodiment, an example in which the covering material 20 is welded to the molded tank body 12 is shown. However, the present invention is not limited to this. For example, as shown in FIG. The upper half 20A and the lower half 20B may be set in the mold 30 for molding, and the tank body 12 may be molded by blowing air from the air nozzle 34 into the parison 32 in the mold 30. In this manufacturing method, the upper half 20A and the lower half 20B are welded to the tank body 12 as the tank body 12 is molded, and the upper half 20A and the lower half 20B can be welded at the joint flange portion 20D.

  In the above-described embodiment, the example in which each fiber 26 constituting the covering material 20 is made of the same resin material as that of the outer shell 16 is shown. However, the present invention is not limited to this example. You may comprise with another resin material. In this case, each of the fibers 26 is preferably configured using a resin material having good weldability to the outer shell 16.

  Furthermore, in the above-described embodiment, an example in which the tank main body 12 is made of a resin material as a whole has been shown. However, the present invention is not limited to this, and the tank main body 12 has at least an outermost layer that forms an outer surface, that is, an outer shell. It is sufficient if 16 is made of a resin material.

  Furthermore, in the above-described embodiment, an example in which the internal space of each fiber 26 constituting the covering material 20 is an air layer is shown. However, the present invention is not limited to this, and for example, the inside of each fiber 26 is thermally insulated. The gas may be filled with good gas, or the heat transfer material in each fiber 26 may be reduced (negative pressure or vacuum).

  Further, in the above-described embodiment, the example in which the tank body 12 is covered with the covering material 20 over substantially the entire circumference (substantially the entire outer surface 16A) is shown, but the present invention is not limited to this, for example, In the configuration in which the heat source is mounted on a specific side with respect to the vehicle fuel tank 10, the heat source side of the tank body 12 may be covered with the covering material 20.

  Furthermore, in the above-described embodiment, the example in which the covering material 20 is configured by the knitted fabric 25 of the string-like body 24 has been shown. However, the present invention is not limited to this, and for example, a plurality of fibers 26 are arranged in a specific direction. The covering material 20 may be formed by laminating the lamina impregnated with the resin in a single layer or by laminating. When laminating, the orientation angles of the plurality of fibers 26 may be matched or different.

It is a side view showing typically the outline whole composition of the fuel tank for vehicles concerning the embodiment of the present invention. It is sectional drawing which expands and shows typically "2" part of FIG. It is sectional drawing which expands and shows typically "3" part of FIG. It is a top view showing typically the knitting which constitutes the covering material of the fuel tank for vehicles concerning the embodiment of the present invention. It is sectional drawing which shows typically the knitted fabric which comprises the coating | covering material of the vehicle fuel tank which concerns on embodiment of this invention. It is a perspective view showing typically the hollow fiber which constitutes the covering material of the fuel tank for vehicles concerning the embodiment of the present invention. It is a figure which shows typically the string-like body which comprises the coating | covering material of the fuel tank for vehicles which concerns on embodiment of this invention, (A) is a perspective view, (B) is sectional drawing. It is a sectional side view which shows the manufacturing process of the fuel tank for vehicles which concerns on embodiment of this invention. It is a sectional side view which shows the manufacture process by the other manufacturing method of the fuel tank for vehicles which concerns on embodiment of this invention.

Explanation of symbols

10 Vehicle fuel tank (fuel tank structure)
12 Tank body 16 Outer shell (outermost layer)
20 Coating Material 20D Joint Flange (Coating Material Joint)
24 String-like body 25 Knitted fabric 26 Fiber (hollow fiber)

Claims (6)

  A fuel tank structure in which at least an outer surface of a fuel tank main body made of a resin material is coated with a covering material made of resin hollow fibers.   The fuel tank structure according to claim 1, wherein the covering material is welded to an outer surface of the fuel tank body.   The fuel tank structure according to claim 1 or 2, wherein the hollow fiber and the outermost layer of the tank body are made of the same kind of resin material.   The fuel tank structure according to any one of claims 1 to 3, wherein the covering material is formed as a knitted string-like body in which the hollow fibers are bundled and fixed.   The fuel tank structure according to any one of claims 1 to 4, wherein an end of the hollow fiber is closed at a peripheral edge of the covering material. The outer surface of the tank is covered with different portions with the plurality of coating materials,
The fuel tank structure according to claim 5, wherein an end of the hollow fiber is closed at a connecting portion of the plurality of covering materials.

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