JP5609705B2 - Fuel tank structure - Google Patents

Description

  The present invention relates to a fuel tank structure.

  Some fuel tank structures provided in vehicles such as automobiles have convex portions formed with a part of the fuel tank facing inward. For example, the fuel tank described in Patent Document 1 has a structure in which the position restricting portion is suspended or erected from the upper wall and the lower wall of the tank body. Due to the position restricting portion, there is a portion where the inner dimension of the fuel tank is locally short.

  In a fuel tank composed of a resin material (thermoplastic resin), the resin material may be in a molten state when the fuel tank is molded. In the fuel tank in which the inward convex portion is formed as described above, deformation of the convex portion may cause welding between the tips of the convex portions or between the tips of the convex portions and other portions of the fuel tank. There is. Actually, in order to avoid such welding, it is necessary to shorten the protruding length of the convex portion, and the degree of freedom in setting the shape of the fuel tank is low.

JP 2010-195127 A

  In view of the above fact, an object of the present invention is to make it possible to suppress the welding of convex portions formed inward in a fuel tank structure having a fuel tank body made of a thermoplastic material.

  In the first aspect of the present invention, a fuel tank body that is made of a thermoplastic resin and can accommodate fuel therein, a convex portion that is formed inward from the fuel tank body, and an inner surface of the fuel tank body The convex portion and a high melting point member that is provided on at least one of the opposing surfaces facing the convex portion and is made of a material having a melting point higher than that of the thermoplastic resin constituting the fuel tank main body.

  In this fuel tank structure, a convex portion is formed inward from the fuel tank main body, and a portion facing the convex portion in the fuel tank main body is an opposing surface. On the inner surface of the fuel tank main body, a high melting point member made of a material having a higher melting point than the thermoplastic resin constituting the fuel tank main body is provided on at least one of the convex portion and the opposing surface. Therefore, when the fuel tank body is manufactured by blow molding or the like, if the temperature is set so that the fuel tank body melts and the high melting point member does not melt, the high melting point members, or the high melting point member and the convex portion or the opposed surface are Even if it contacts, these welding is suppressed and the welding of a convex part is also suppressed.

  The fuel tank main body may be provided with two convex portions facing each other. In this configuration, the other convex portion has an opposing portion (having a facing surface) with respect to any one convex portion. )

  According to a second aspect of the present invention, in the first aspect of the present invention, the convex portion includes an inner deformation portion that is provided in the fuel tank main body and reduces the volume of the fuel tank main body by being deformed inward. And at least one of the said opposing surface is provided in the said internal deformation | transformation part.

  Therefore, for example, when the inside of the fuel tank body is at a lower pressure than the surroundings, the volume of the fuel tank body can be reduced by the deformation of the inner deformation portion.

  In addition, since at least one of the convex portion and the facing surface is provided in the inner deformation portion, the deformation of the inner deformation portion can be limited to a predetermined range by contact between the convex portion and the facing surface.

  Since at least one of the convex portion and the opposing surface is provided with the high melting point member, welding during the manufacture of the fuel tank body is suppressed. As a result, the distance between the tip of the convex portion and the facing surface can be set short in advance.

  According to a third aspect of the present invention, in the second aspect of the present invention, the inner deformation portion is provided on at least one of an upper wall and a lower wall of the fuel tank body.

  Accordingly, the volume of the fuel tank body can be reduced by moving the inner deformation portion of the fuel tank body in the vertical direction.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the high melting point member is provided on both the convex portion and the facing surface.

  Thus, by providing the high melting point member on both the convex portion and the opposing surface, welding can be more effectively suppressed as compared with the configuration provided on only one of them.

  According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the high melting point member is provided only at the tip of the convex portion.

  Therefore, the range in which the high melting point member is provided can be narrowed and the cost can be reduced as compared with the configuration in which the high melting point member is provided on the entire convex portion.

  In invention of Claim 6, in the invention of any one of Claims 1-5, the said high melting point member is comprised with resin.

  Therefore, the workability is improved as compared with a configuration using a material other than resin as the high melting point member. By using a material having a coefficient of thermal expansion close to that of the thermoplastic resin constituting the fuel tank main body, it is possible to improve the bonding property with the thermoplastic resin constituting the fuel tank main body.

  Since this invention set it as the said structure, the welding of the convex part formed toward the inner side in the fuel tank structure which has a fuel tank main body made from a thermoplastic material can be suppressed.

It is sectional drawing which shows the fuel tank to which the fuel tank structure of 1st Embodiment of this invention was applied. It is explanatory drawing which shows the manufacturing process of the fuel tank structure of 1st Embodiment of this invention to (A)-(D) in order. It is sectional drawing which shows the fuel tank to which the fuel tank structure of 2nd Embodiment of this invention was applied. It is explanatory drawing which shows a part of manufacturing process of the fuel tank structure of 2nd Embodiment of this invention. It is sectional drawing which shows the fuel tank to which the fuel tank structure of 3rd Embodiment of this invention was applied.

  FIG. 1 shows a fuel tank 10 to which the fuel tank structure 12 of the first embodiment of the present invention is applied. The fuel tank 10 has a fuel tank main body 14 capable of containing fuel therein. The shape of the fuel tank body 14 is not particularly limited, but in the present embodiment, it is formed in a substantially rectangular parallelepiped box shape.

  The fuel tank main body 14 has an upper tank constituent member 14U and a lower tank constituent member 14L made of thermoplastic resin (for example, PE). A substantially box-shaped fuel tank body 14 is configured by joining the periphery of these tank constituent members.

  On the upper wall 14T of the fuel tank body 14, a thin-walled portion 16 having a closed curve shape (for example, a circle or a quadrangle) as viewed from above is formed. The thin portion 16 is thinner than the surrounding portion (plate-like portion) constituting the upper wall 14T and has a bellows shape that undulates in the vertical direction, and is easily deformed.

  The inner portion of the thin portion 16 is a variable volume portion 18 that is displaced downward by deformation of the thin portion 16. That is, the volume of the fuel tank main body 14 is reduced by the displacement of the volume variable portion 18 downward. Furthermore, in the present embodiment, the volume of the fuel tank main body 14 can be increased by displacing the volume variable portion 18 upward. That is, the volume can be changed according to the amount of evaporated fuel in the fuel tank body 14.

  In the variable volume portion 18 (particularly in the present embodiment, when the fuel tank main body 14 is seen from above in plan view), there is a deformation limiting convex portion 20 that protrudes downward. Is formed. The deformation limiting convex part 20 is an example of the convex part of the present invention.

  On the other hand, a deformation limiting base portion 22 is also formed on the lower wall 14B of the fuel tank body 14 so as to protrude upward at a position facing the deformation limiting convex portion 20. The deformation limiting base part 22 faces the deformation limiting convex part 20 in the vertical direction, and is an example of the facing part of the present invention. In particular, the center of the deformation limiting base portion 22 is an opposing surface 24 that faces the deformation limiting convex portion 20.

  On the inner surface of the fuel tank main body 12, a welding sheet material 26 is disposed in a portion including at least the lower end of the deformation limiting convex portion 20. Further, a welding sheet material 28 is also arranged on the facing surface 24 of the deformation limiting base 22 and faces the upper welding sheet material 26.

  As shown in FIG. 2B, the welding sheet materials 26 and 28 are composed of a sheet base 30 made of the same material as the upper tank constituent member 14U and the lower tank constituent member 14L, and the same shape as the sheet base 30. And a two-layer structure having a thin film layer 32 bonded to one surface of the sheet base 30.

  The thin film layer 32 is made of a material having a higher melting point than that of the upper tank constituent member 14U and the lower tank constituent member 14L (in this embodiment, for example, a fluororesin, PA, or PPS resin). The sheet base portion 30 of the welding sheet material 26 is welded to the deformation limiting convex portion 20. In addition, the sheet base 30 of the welding sheet material 28 is also welded to the deformation limiting base 22. Therefore, the upper welding sheet material 26 and the lower welding sheet material 28 are opposed to each other vertically with a predetermined distance D1 with the respective thin film layers 32 partially facing each other. Since the welding sheet materials 26 and 28 are formed into a thin film as a whole, the distance D1 is substantially equal to the distance between the deformation limiting convex part 20 and the deformation limiting base part 22.

  When the pressure in the fuel tank 10 becomes negative, the thin portion 16 is deformed and the volume variable portion 18 moves downward, and the volume of the fuel tank 10 is reduced. Thereby, it is suppressed that the inside of the fuel tank 10 becomes an excessive negative pressure. When the amount of downward movement of the variable volume portion 18 reaches a predetermined amount, the tip of the deformation limiting projection 20 and the opposed surface 24 of the deformation limiting base 22 (strictly speaking, the thin film layers of the welding sheet materials 26 and 28) 32) are in contact with each other, and excessive displacement of the variable volume portion 18 is suppressed.

  In the fuel tank structure 12 of the first embodiment having such a configuration, the deformation limiting convex portion 20 and the deformation limiting base portion 22 are inadvertently welded during manufacturing as will be described in detail below. The situation is suppressed.

  When manufacturing the fuel tank 10 according to the first embodiment, first, as shown in FIG. 2A, the upper sheet material 34U constituting the upper tank constituting member 14U and the lower sheet constituting the lower tank constituting member 14L. A material 34L is prepared. The upper sheet material 34U and the lower sheet material 34L are both made of PE, and are flat before being molded.

  Next, as shown in FIG. 2 (B), in the lower surface of the upper sheet material 34U, at a position including the lower end of the deformation limiting convex portion 20 after molding (in the present embodiment, the center of the lower surface of the upper sheet material 34U). The welding sheet material 26 is disposed. At this time, the sheet base 30 is set to face (up) the upper sheet material 34U. Similarly, the welding sheet material 28 is disposed at a position including the portion that becomes the opposing surface 24 after molding in the upper surface of the lower sheet material 34L (in the present embodiment, the center of the upper surface of the lower sheet material 34L). At this time, the sheet base 30 is set to face (become down) the lower sheet material 34L.

  Then, the sheet base 30 and the upper sheet material 34 </ b> U are welded at a temperature higher than these melting temperatures and lower than the melting temperature of the thin film layer 32. Similarly, the sheet base 30 and the lower sheet material 34 </ b> L are welded at a temperature that is higher than their melting temperature and lower than the melting temperature of the thin film layer 32.

  Next, as shown in FIG. 2 (C), the upper sheet material 34U and the lower sheet material 34L are put into a mold 36 having an upper mold 36U and a lower mold 36U, and blow molding is performed. First, the upper mold 36U and the lower mold 36U are clamped to weld the peripheral portions of the upper sheet material 34U and the lower sheet material 34L. Next, compressed air is blown into the mold 36 to mold the upper sheet material 34U and the lower sheet material 34L into the shape of the fuel tank main body 14. The temperature at this time is higher than the melting temperature of the upper sheet material 34U and the lower sheet material 34L and lower than the melting temperature of the thin film layer 32. Thereby, as shown in FIG. 2D, the fuel tank 10 having a desired shape can be obtained without melting the thin film layer 32.

  Since the upper sheet material 34U and the lower sheet material 34L are equal to or higher than the melting temperature at the stage immediately after molding, for example, when the deformation limiting convex part 20 hangs down, the deformation limiting convex part 20 and the deformation limiting base part 22 are An approach is assumed. However, in the present embodiment, the welding sheet materials 26 and 28 welded to the deformation limiting convex portion 20 and the deformation limiting base portion 22 are opposed to each other at the respective thin film layers 32. Since the molding temperature does not reach the melting point of the thin film layer 32 and the thin film layer 32 is not melted, even if the deformation limiting convex portion 20 and the deformation limiting base portion 22 approach and the thin film layer 32 contacts, Not welded.

  Thus, in the fuel tank 10 to which the fuel tank structure 12 of the present embodiment is applied, even when the deformation limiting convex portion 20 and the opposing surface 24 of the deformation limiting base portion 22 are close to each other, at the time of molding (molten state) Therefore, since the welding accompanying these deformations is suppressed, the fuel tank 10 can have an original shape (desired shape).

  Further, even if the distance D1 between the deformation limiting convex part 20 and the deformation limiting base part 22 is set short, it becomes possible to suppress these weldings, so these shapes are set at a desired distance (shorter distance). It is also possible to increase the degree of freedom of the shape of the fuel tank 10.

  Furthermore, in the fuel tank structure according to the first embodiment, the upper tank constituent member 14U and the lower tank constituent member 14L are substantially thicker at the portion where the welding sheet material 26 is welded, so that the rigidity becomes higher. Thereby, when the volume variable part 18 moves downward and the deformation limiting convex part 20 and the deformation limiting base part 22 come into contact with each other, the contact portion and the vicinity thereof are difficult to deform, and the deformation limiting convex part 20 and the deformation limiting It becomes possible to make the original action (action of suppressing deformation) of the base portion 22 higher.

  FIG. 3 shows a fuel tank 50 to which the fuel tank structure 52 of the second embodiment of the present invention is applied. In the second embodiment, the same components and members as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the second embodiment, coating layers 54 and 56 are formed instead of the welding sheet materials 26 and 28 of the first embodiment. The coating layers 54 and 56 are each made of a material having a melting point higher than that of the upper tank constituent member 14U and the lower tank constituent member 14L (for example, a resin such as fluororesin, PA, or PPS), like the thin film layer 32 of the first embodiment. It is configured.

  In manufacturing the fuel tank 50 of the second embodiment, instead of the process shown in FIG. 2B, as shown in FIG. 4, a spraying device 58 (or a coating device or the like) is used, and the upper tank is used. The coating layers 54 and 56 may be coated on predetermined portions of the constituent member 14U and the lower tank constituent member 14L. If necessary, the coating materials 54 and 56 may be coated after the same material as the upper tank constituent member 14U and the lower tank constituent member 14L is first coated to improve the weldability. Except for this, the fuel tank 50 can be manufactured in the same manufacturing process as in the first embodiment.

  Also in the fuel tank 50 of the second embodiment configured as described above, the deformation limiting convex portion 20 and the opposing surface 24 of the deformation limiting base portion 22 are close to each other as in the fuel tank 10 of the first embodiment. Also, welding during molding is suppressed. In addition, it is possible to set a short interval between the deformation limiting convex part 20 and the deformation limiting base part 22, and the degree of freedom of the shape of the fuel tank 50 is increased.

  FIG. 5 shows a fuel tank 70 to which the fuel tank structure 72 of the third embodiment of the present invention is applied. In the third embodiment, the same components and members as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the third embodiment, unmelted thin films 74 and 76 are attached in place of the welding sheet materials 26 and 28 of the first embodiment and the coating layers 54 and 56 of the second embodiment. The non-molten thin films 74 and 76 are formed in a thin film shape from metal or the like, and have a melting point higher than that of the upper tank constituent member 14U and the lower tank constituent member 14L.

  In the present embodiment, embedded pieces 78 embedded in the upper tank constituent member 14U and the lower tank constituent member 14L are formed on the periphery of the non-melted thin films 74 and 76. Since the embedded piece 78 acts as an anchor, positional displacement and dropout with respect to the upper tank constituent member 14U and the lower tank constituent member 14L are suppressed.

  Also in the fuel tank 70 of the third embodiment configured as described above, the deformation limiting convex portion 20 and the deformation limiting base portion 22 are similar to the fuel tank 10 of the first embodiment and the fuel tank 50 of the second embodiment. Even when the facing surface 24 is close, welding during molding is suppressed. In addition, it is possible to set a short interval between the deformation limiting convex part 20 and the deformation limiting base part 22, and the degree of freedom of the shape of the fuel tank 50 is increased.

  In addition, in 2nd Embodiment and 3rd Embodiment, since the sheet | seat base 30 of the welding sheet material 26 becomes unnecessary compared with 1st Embodiment, it is possible to achieve weight reduction of a fuel tank.

  Further, in the first embodiment and the second embodiment, since the resin is used as the high melting point member of the present invention, it is easier to process than the configuration using the metal as the rear melting point member as in the third embodiment. Is expensive. Further, as the thermal expansion coefficient of the resin constituting the high melting point member, it is also possible to select a material close to the thermal expansion coefficient of the thermoplastic resin constituting the upper tank constituent member 14U and the lower tank constituent member 14L. Further, it becomes possible to improve the followability of the high melting point member with respect to the deformation of the upper tank constituent member 14U and the lower tank constituent member 14L.

  In the above, although the deformation | transformation restriction convex part 20 was mentioned as an example of the convex part of this invention, as a convex part, it is not limited to this. For example, there is a fuel tank of a type in which a wall member (baffle) for suppressing the flow of fuel is formed inside. In such a fuel tank, the above-mentioned welding sheet is placed on the front end of the baffle and its opposite surface. Materials 26 and 28, coating layers 54 and 56, non-melted thin films 74 and 76, and the like may be provided.

  Furthermore, the structure without the deformation | transformation restriction base part 22 may be sufficient. That is, even if a portion such as the deformation limiting base portion 22 is not formed for one convex portion, the surface facing the convex portion exists inside the fuel tank. Therefore, it is good also as a structure which provided the welding sheet | seat materials 26 and 28, the coating layers 54 and 56, the non-melting thin films 74 and 76, etc. in at least one of the front-end | tip of a convex part, and an opposing surface.

  The welding sheet materials 26 and 28, the coating layers 54 and 56, and the non-melted thin films 74 and 76 can be used in combination. For example, the welding sheet material 26 may be welded to the tip of the deformation limiting projection 20, and the coating layer 56 and the non-melting thin film 76 may be provided on the facing surface 24 of the deformation limiting base 22.

  High melting point members (welding sheet materials 26 and 28, coating layers 54 and 56, non-melting thin films 74 and 76) are preferably provided on both the convex portion and the opposing surface from the viewpoint of suppressing the above-described welding. However, you may provide in either one. However, when it is provided on either side, when the convex portion and the facing surface are in contact with each other through the high melting point member in a molten state, the convex portion or the facing surface on which the high melting point member is not provided is easily deformed. On the other hand, when the high melting point member is provided on both the convex portion and the opposing surface, when the convex portion and the opposing surface are in contact with each other through the high melting point member in a molten state, local deformation in both contact portions is caused. Can be suppressed.

  Further, the high melting point member may be provided not only at the front end of the convex portion and the opposed surface thereof but also in a wider range. However, in the fuel tank (the fuel tanks 10, 50, 70 in the first to third embodiments) configured to form the thin portion 16 and move the volume variable portion 18 downward, a high melting point member is attached to the thin portion 16. If provided, there may be a resistance to deformation of the thin portion 16. Accordingly, it is preferable to provide a high melting point member while avoiding a portion to be deformed such as the thin portion 16. In particular, when a high melting point member is provided only at the tip of the deformation limiting convex portion 20, the substantial area of the high melting point member becomes narrow and the amount of material can be reduced, thereby reducing the cost.

  As the fuel tank according to the present invention, the fuel tank having the structure in which the variable volume portion 18 is formed is described above. However, the present invention is also applied to a fuel tank in which such a variable volume portion 18 is not formed. (The fuel tank in which the wall member described above is formed is an example thereof).

  The variable volume portion 18 (inner deformation portion) may be provided on the lower wall 14B, or may be provided on both the upper wall 14T and the lower wall 14B. Furthermore, the present invention can also be applied to a fuel tank having a structure in which an inner deformation portion is provided on the side wall.

DESCRIPTION OF SYMBOLS 10 Fuel tank 12 Fuel tank structure 14 Fuel tank main body 14U Upper tank structural member 14L Lower tank structural member 14T Upper wall 14B Lower wall 16 Thin part 18 Volume variable part (inner deformation part)
20 Deformation restriction convex part 22 Deformation restriction stand part 24 Opposing surface 26 Welding sheet material 28 Welding sheet material 30 Sheet base part 32
50 Fuel tank 52 Fuel tank structure 54 Coating layer (high melting point member)
58 Spraying device 70 Fuel tank 72 Fuel tank structure 74, 76 Non-molten thin film (high melting point member)

Claims (6)

A fuel tank body that is made of thermoplastic resin and can contain fuel; and
A convex portion formed inward from the fuel tank body;
A high melting point member made of a material having a higher melting point than the thermoplastic resin constituting the fuel tank main body provided on at least one of the convex portion and the opposing surface facing the convex portion on the inner surface of the fuel tank main body. When,
Having fuel tank structure. An inner deformation portion that is provided in the fuel tank body and deforms inward to reduce the volume of the fuel tank body,
The fuel tank structure according to claim 1, wherein at least one of the convex portion and the facing surface is provided in the inner deformation portion.   The fuel tank structure according to claim 2, wherein the inner deformation portion is provided on at least one of an upper wall and a lower wall of the fuel tank main body.   The fuel tank structure according to any one of claims 1 to 3, wherein the high melting point member is provided on both the convex portion and the facing surface.   The fuel tank structure according to claim 4, wherein the high melting point member is provided only at a tip portion of the convex portion.   The fuel tank structure according to any one of claims 1 to 5, wherein the high melting point member is made of a resin.

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