JP2009137488A - Fuel tank - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel tank for an automobile which prevents outflow of fuel oil and its steam, has a simple structure of an inlet part of the fuel tank, and easy to manufacture. <P>SOLUTION: The fuel tank 1 made of a thermoplastic synthetic resin is constituted of an upper shell part 10 and a lower shell part 20 respectively divided and separately molded by injection molding. The inlet part 13 is integrally formed on the upper shell part. A check valve 18 is arranged in an inlet of an inner side of the upper shell part of the inlet part. The periphery of the inlet of the inner side of the upper shell part of the inlet part is surrounded by an steam flow-out preventing wall 17 integrally extended downward from the upper shell part. The length of the steam flow-out preventing wall is extended below the liquid level 2 reached when the fuel oil fills the fuel tank. When the check valve 18 opens, the frond edge of the check valve is brought into contact with the steam outflow preventing wall 17, so that the opening of the check valve is regulated. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an automobile fuel tank having an inlet for injecting fuel oil.

As a structure of an automobile fuel tank, an inlet portion for injecting fuel into the fuel tank is provided on the outer wall of the fuel tank.
Conventionally, such fuel tanks have been made of metal, but in recent years, they have been made of thermoplastic resin due to the weight reduction of vehicles, the absence of rust, and the ease of molding into a desired shape. It has come to be used.

  Conventionally, this thermoplastic resin fuel tank is often formed by blow molding, but a nipple for attaching an inlet hose is attached to the inlet portion. In order to attach the nipple, first, a separately formed nipple may be fused to the fuel tank. In this case, since a hole was made in the fuel tank and the nipple was fused by hot plate, the number of work steps was great.

  Further, when fitting the nipple to the fuel tank, it is necessary to form in advance a cylindrical attachment portion for mounting the nipple on the fuel tank by blow molding. And the cylindrical nipple which has a flange part on the outer periphery was formed by injection molding etc., and the nipple was inserted in the attachment part. However, it was necessary to ensure a sealing property between the nipple and the fuel tank.

  Therefore, in recent years, the synthetic resin fuel tank 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 joint peripheral edge parts of the upper shell part and the lower shell part are melted together. A method of forming a fuel tank by wearing is also performed (for example, see Patent Document 1). In this case, it is easy to form an inlet part for attaching the inlet hose to the upper shell part, and accessories such as a fuel pump are easily mounted inside the fuel tank before the upper shell part and the lower shell part are fused. You can also. Further, ribs or beams for reinforcement or mounting can be easily formed on the inner surfaces of the upper shell portion and the lower shell portion.

  However, as shown in FIG. 3, in the lower inlet pipe 114 inserted into the fuel tank of the inlet hose, in order to prevent additional refueling after a full tank and to prevent the above gasoline from flowing out from the refueling port. In addition, it is necessary to dispose the tip of the lower inlet pipe 114 below the liquid level when the tank is full, and a longer lower inlet pipe 114 is required.

For this reason, it is necessary to prepare many types of lower inlet pipes 114 having different lengths according to the shape of the fuel tank 101. Further, in order to attach the lower inlet pipe 114 so as to be disposed below the liquid level when the tank is full, the lower inlet pipe 114 is attached to the inlet portion 113 by hot plate welding or the like. And strict space management is required, which takes time and cost.
In some cases, a long lower inlet pipe is formed so as to reach the bottom of the fuel tank and attached to the inside of the fuel tank 101 (see, for example, Patent Document 2).

  Also, as shown in FIG. 4, there is a fuel reservoir 215 formed at the tip of the lower inlet pipe 214 to accumulate fuel oil so that fuel vapor does not flow out of the lower inlet pipe 214 (for example, , See Patent Document 3). However, in this case, it is necessary to attach a separately formed fuel reservoir 215 to the tip of the lower inlet pipe 214, which complicates the structure, takes time, and increases costs.

  Further, in order to prevent the fuel oil and its vapor from flowing out, a check valve is attached. As shown in FIG. 5, one end of the check valve 318 is attached to the inner wall of the fuel tank 301 on the inner surface of the outer wall. (For example, refer to Patent Document 4). However, in this case, the check valve 318 may be excessively opened and deformed, and in order to prevent the check valve 318 from being deformed, a member for regulating the opening of the check valve 318 is required. High accuracy in the position and dimensions of the members and check valve 318 was required.

JP-A-11-34180 Japanese Patent Laid-Open No. 2005-199885 JP-A-8-91062 JP 2001-47874 A

  Accordingly, the present invention is intended to provide an automobile fuel tank that prevents the fuel oil and its vapor from flowing out, has a simple structure of the inlet portion of the fuel tank, and is easy to manufacture.

In order to solve the above-mentioned problems, the present invention of claim 1 is a thermoplastic synthetic resin in which the joining peripheral edge portions of the upper shell portion and the lower shell portion, which are divided and separately formed by injection molding, are united and integrated. In the fuel tank made of
An inlet portion for injecting fuel oil into the upper shell portion is formed integrally, and the inlet on the inner surface side of the upper shell portion of the inlet portion is opened when fuel oil is injected, and fuel oil or fuel oil vapor flows out of the fuel tank. A check valve to block
Surrounding the inlet on the inner surface side of the upper shell part of the inlet part with a steam spill prevention wall integrally extending downward from the upper shell part, the length of the steam spill prevention wall is filled with fuel oil in the fuel tank Extend below the liquid level of the fuel oil when
The fuel tank is characterized in that when the check valve is opened, the tip of the check valve comes into contact with the vapor outflow prevention wall, and the opening degree of the check valve is regulated.

  In the first aspect of the present invention, the fuel tank is made of a thermoplastic synthetic resin which 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. 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 by injection molding.

In addition, since the upper shell portion and the lower shell portion are formed separately, component mounting ribs and reinforcing ribs can be formed inside thereof, and it is possible to attach built-in components or improve the strength of the fuel tank. Easy to do.
Since the joint peripheries of the molded upper shell and lower shell are fused, the joint peripheries of the upper shell and lower shell are firmly and integrally joined together, and the upper shell and lower shell 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. Moreover, the sealing property of a joining peripheral part can also be ensured.

  Since the inlet part for injecting fuel oil into the upper shell part is integrally formed, it is integrally formed at the same time as the molding of the upper shell part, and the inlet part and the upper shell part are integrated to ensure a sealing property. In addition, since the inlet portion is not formed separately, it does not take time and costs can be reduced.

  An inlet on the inner surface side of the upper shell portion of the inlet portion was opened when fuel oil was injected, and a check valve was provided to block outflow of fuel oil or fuel oil vapor from the inside of the fuel tank. For this reason, while preventing backflow of the fuel oil at the time of excessive injection | pouring of fuel oil, discharge | emission of the vapor | steam of fuel oil at times other than the time of injection | pouring can be prevented. Further, the check valve is opened when fuel oil is injected, and the injection can be made smooth.

  Surrounding the inlet on the inner surface side of the upper shell part of the inlet part with a steam outflow prevention wall that extends downward integrally from the upper shell part, the length of the steam outflow prevention wall is filled with fuel oil in the fuel tank It extended below the liquid level of the fuel oil. For this reason, when the fuel oil is injected from the inlet portion and the fuel oil becomes full in the fuel tank, the inlet portion can be sealed by the steam outflow prevention wall, and the fuel oil vapor is discharged from the inlet portion. It can be prevented from being discharged.

  When the check valve opens, the tip of the check valve comes into contact with the steam spill prevention wall, and the opening of the check valve is regulated, so that the check valve can be prevented from opening excessively. Can be prevented from being deformed. The steam outflow prevention wall and the inlet portion can be formed at the same time during molding, the position can be defined with high accuracy, and the opening degree of the check valve can be regulated with high accuracy.

  According to the present invention of claim 2, the end of the check valve is fixed to the end of the inlet on the inner surface side of the upper shell portion, and normally the inlet on the inner surface side of the inlet portion of the upper shell portion is closed by a spring, A fuel tank that opens when oil is injected.

  In the present invention of claim 2, the end of the check valve is fixed to the end of the inlet on the inner surface side of the upper shell portion, and normally the inlet on the inner surface side of the inlet portion of the upper shell portion is closed by a spring, When oil is injected, it can be opened automatically. For this reason, when fuel is injected, the fuel oil is reliably allowed to flow into the fuel tank, and other than that, the inlet of the inlet portion is reliably closed, and fuel oil vapor and fuel discharge can be reliably prevented.

  The present invention of claim 3 is a fuel tank in which the inlet portion is formed at a corner portion of the boundary between the upper wall and the side wall of the upper shell portion, and the steam outflow prevention wall is formed from the upper wall of the upper shell portion to the side wall. is there.

  According to the third aspect of the present invention, the inlet portion is formed at the corner portion of the boundary between the upper wall and the side wall of the upper shell portion, and the steam outflow prevention wall is formed from the upper wall to the side wall of the upper shell portion. For this reason, the steam outflow prevention wall reliably closes the periphery of the inlet of the inlet portion formed at the corner portion at the boundary between the upper wall and the side wall of the upper shell portion, and the fuel oil vapor and fuel can be reliably prevented from being discharged.

  According to a fourth aspect of the present invention, the inlet portion is formed on the upper wall of the upper shell portion, and the steam outflow prevention wall is a fuel tank formed from the upper wall of the upper shell portion.

  In this invention of Claim 4, the inlet part was formed in the upper wall of an upper shell part, and the steam outflow prevention wall was formed from the upper wall of the upper shell part. For this reason, the steam outflow prevention wall reliably blocks the periphery of the inlet of the inlet portion formed in the upper wall of the upper shell portion, and the fuel oil vapor and fuel can be reliably prevented from being discharged.

  According to a fifth aspect of the present invention, there is provided a fuel tank in which a protrusion that contacts the check valve when the check valve is opened is formed on a side surface of the steam outflow prevention wall.

  According to the fifth aspect of the present invention, since the protrusion that contacts the check valve when the check valve is opened is formed on the side surface of the steam outflow prevention wall, the tip of the check valve is formed on the steam outflow prevention wall. The check valve can be smoothly opened and closed without contact and without being deformed at the tip or caught on the steam outflow prevention wall.

  According to the present invention of claim 6, 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, and the inner resin layer is high. It is formed of density polyethylene (HDPE), the outer sheet layer is formed of a fuel-permeable multilayer resin sheet, and the layer in contact with the inner resin layer of the fuel-permeable multilayer resin sheet is compatible with high-density polyethylene (HDPE). A fuel tank made of a certain material.

In the present invention of claim 6, since the upper shell portion and the lower shell portion are formed of a fuel-permeable multilayer resin sheet having an inner resin layer and a barrier layer, it is possible to obtain a fuel tank excellent in strength and fuel permeability. it can.
Since the inner resin layer is formed of high-density polyethylene (HDPE), it is easy to mold in injection molding, and the strength of the fuel tank can be increased.

  In the fuel-permeable multilayer resin sheet, the layer in contact with the inner resin layer of the fuel-permeable multilayer resin sheet was formed of a material compatible with high-density polyethylene (HDPE). For this reason, fuel permeation is prevented by the fuel permeation-resistant layer, and a layer having good adhesion with high-density polyethylene (HDPE) is formed on the surface of the fuel permeation-resistant layer facing the inner resin layer and the outer resin layer. In addition, the inner resin layer and the fuel permeation-resistant multilayer resin sheet can be firmly bonded, and the strength of the outer wall of the fuel tank can be improved.

Since the inlet part for injecting the fuel oil into the upper shell part is integrally formed, the sealing property between the inlet part and the upper shell part can be secured.
Surrounding the inlet on the inner surface side of the upper shell part of the inlet part with a steam spill prevention wall integrally extending downward from the upper shell part, the length of the steam spill prevention wall is filled with fuel oil in the fuel tank When the fuel oil is full in the fuel tank, the inlet part can be sealed with a steam spill prevention wall, and the fuel can be sealed from the inlet part. Oil vapor can be prevented from being discharged.
When the check valve opens, the tip of the check valve comes into contact with the steam spill prevention wall, and the opening of the check valve is regulated, so that the check valve can be prevented from opening excessively. Can be prevented from being deformed.

An embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a cross-sectional view of a fuel tank 1 of the present invention. FIG. 2 is a partial cross-sectional view of a corner portion of the fuel tank 1 of the present invention.

As shown in FIG. 1, the fuel tank 1 is composed of 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 formed by injection molding.
The fuel tank 1 can be divided not only into the upper shell portion 10 and the lower shell portion 20 but also into three or more.

An inlet portion 13 shown in FIG. 1 is formed in the upper shell portion 10. The inlet portion 13 is for attaching an inlet hose (not shown) for injecting fuel into the fuel tank 1. Reference numeral 15 denotes a cut-off valve that prevents fuel leakage from the fuel tank 1 when the vehicle falls.
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.

  A sub tank 5 is formed on the inner surface of the lower shell portion 20, and the fuel pump unit 4 is attached in the sub tank 5 before being joined to the upper shell portion 10. The sub tank 5 is provided so that the fuel pump unit 4 can reliably send the fuel in the fuel tank 1 to the engine when the vehicle is tilted or vibrated. A pipe extends from the fuel pump unit 4 and is connected to the fuel main port mounting portion 23 of the lower shell portion 20. A fuel pipe (not shown) for sending fuel to the engine is attached to the fuel main port attachment portion 23.

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 and 22 that project outward from the outer surface at substantially right angles over the entire circumference. The joining peripheral edge portions 11 and 21 and the flange portions 12 and 22 are fused to face each other.
As shown in FIG. 1, 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 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 can be formed by injection molding of only a thermoplastic synthetic resin. In this case, high density polyethylene (HDPE) can be used.

  The thermoplastic synthetic resin constituting the upper shell portion 10 and the lower shell portion 20 is not only high density polyethylene (HDPE) but also polyoxymethylene (POM), ethylene vinyl alcohol copolymer (EVOH), nylon, polybutylene terephthalate, At least one material of polyethylene terephthalate and polyphenylene sulfide can be used.

Next, an embodiment of the present invention will be described with reference to FIGS.
The inlet portion 13 is formed at a corner portion at the boundary between the upper wall and the side wall of the upper shell portion 10. The inlet portion 13 is formed at the same time when the upper shell portion 10 is injection molded. For this reason, the inlet portion 13 and the upper shell portion 10 are integral with each other, there is no gap, and the sealing performance can be ensured, and the labor for forming the inlet portion 13 is not required, and the cost can be reduced. it can.

  The inlet portion 13 extends in a cylindrical shape outward from the outer wall of the fuel tank 1. The cylindrical tip is formed with a protrusion 13b in a circumferential shape. A tip of an inlet hose (not shown) for transferring fuel oil from a fuel injection port (not shown) of the vehicle body to the fuel tank 1 is attached to the inlet portion 13 and attached by tightening the protruding portion 13b with a band or the like. It is done.

  The inlet on the inner surface side of the upper shell portion 10 of the inlet portion 13 forms an opening portion 13 c, and the opening portion 13 c is formed so as not to protrude into the fuel tank 1 from the outer wall of the fuel tank 1. The opening 13c is provided with a check valve 18 that opens when fuel oil is injected and blocks the outflow of fuel oil or fuel oil vapor from the inside of the fuel tank.

As shown in FIG. 2, the check valve 18 is attached to the upper end of the opening 13 c and is attached to be freely opened and closed by a spring 19. For this reason, when fuel oil is injected, the check valve 18 is opened by the flow of the fuel oil, and the fuel oil can be injected smoothly.
When the fuel oil injection is finished, the check valve 18 closes the opening 13 c by the action of the spring 19. For this reason, discharge of the vapor | steam of fuel oil from the fuel tank 1 can be prevented. Moreover, the back flow of the fuel oil when the fuel oil is excessively injected can be prevented.

  The steam outflow prevention wall 17 is formed so as to integrally extend downward from the upper wall to the side wall of the upper shell portion 10 so as to surround the opening portion 13c of the inlet portion 13. The length of the steam outflow prevention wall 17 extends below the liquid level 2 of the fuel oil when the fuel oil is full in the fuel tank 1 and surrounds the opening 13c.

  For this reason, when the fuel tank 1 is full, the steam outflow prevention wall 17 reliably closes the periphery of the inlet portion 13 formed at the corner portion of the boundary between the upper wall and the side wall of the upper shell portion 10. Steam and fuel can be reliably prevented from being discharged. Since the steam outflow prevention wall 17 is formed simultaneously with the molding of the upper shell portion 10, the sealing performance between the steam outflow prevention wall 17 and the upper shell portion 10 can be ensured, and the variation in dimensional system can be minimized.

  As shown in FIG. 2, the steam outflow prevention wall 17 is formed at a position where the tip of the check valve 18 contacts the steam outflow prevention wall 17 when the check valve 18 is opened at a predetermined opening A. . For this reason, the opening degree of the check valve 18 can be regulated. Therefore, the check valve 18 can be prevented from opening excessively, and deformation of the check valve 18 can be prevented. The steam outflow prevention wall 17 and the inlet portion 13 can be formed at the same time during molding, the positions thereof can be defined with high accuracy, and the opening degree of the check valve 18 can be regulated with high accuracy.

  In addition, as shown in FIG. 2, you may form the projection part 17b in the vapor | steam outflow prevention wall 17. As shown in FIG. In this case, when the check valve 18 is opened, the back surface of the check valve 18 can come into contact with the protrusion 17b. For this reason, the front end of the check valve 18 does not come into contact with the steam outflow prevention wall 17, and the front end is not deformed or caught on the steam outflow prevention wall 17, so that the check valve 18 can be opened and closed smoothly. Done.

  The inlet portion 13 can be formed on a flat portion of the upper wall of the upper shell portion 10. In this case, the steam outflow prevention wall 17 is formed to extend downward in a cylindrical shape from the upper wall of the upper shell portion 10 so as to surround the opening 13c of the inlet portion 13. For this reason, the steam outflow prevention wall 17 reliably closes the periphery of the opening 13c of the inlet portion 13 formed on the upper wall of the upper shell portion 10 when the tank is full, thereby reliably preventing the fuel oil vapor and the fuel from being discharged. it can.

As shown in FIG. 1, the upper shell portion 10 and the lower shell portion 20 are respectively an inner resin layer 6 formed by injection molding, and a fuel-resistant permeation that is bonded or fused to the outside after the inner resin layer 6 is molded. It can also be formed from two layers of the outer sheet layer 7 composed of a conductive multilayer resin sheet.
The fuel permeation-resistant multilayer resin sheet can be attached in advance in an injection mold and then injection molded.

  The outer surface of the inner resin layer 6 of the upper shell portion 10 and the lower shell portion 20 is entirely fused to the front ends of the flange portions 12 and 22 with the fuel-permeable multilayer resin sheet integrally. Layer 7 is configured. The fusion of the fuel-permeable multilayer resin sheet can be performed by heating the surface of the fuel-permeable multilayer resin sheet. For this reason, fuel permeation can be prevented up to the entirety of the upper shell portion 10 and the lower shell portion 20 and the tips of the flange portions 12 and 22.

  The fuel permeation-resistant multi-layer resin sheet 3 is formed from, for example, a barrier layer for preventing fuel permeation in which a central layer is made of ethylene vinyl alcohol copolymer (EVOH) or nylon, and modified polyethylene above and below the barrier layer. And a five-layer sheet composed of an outer layer formed of polyethylene (PE) on each 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-permeable multilayer resin sheet 3 can be formed of polyethylene (PE) that is resistant to impact and abrasion, and in this 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.

The embodiment of the present invention is shown and is a sectional view of a fuel tank. 1, showing an embodiment of the present invention, is a cross-sectional view of an inlet portion of a fuel tank. It is sectional drawing of the conventional fuel tank. It is sectional drawing of the other conventional fuel tank. It is sectional drawing of the other conventional fuel tank.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel tank 2 Full liquid level 10 Upper shell 13 Inlet part 13c Opening part 17 Steam outflow prevention wall 17b Protrusion part 18 Check valve 20 Lower shell part

Claims (6)

In the fuel tank made of a thermoplastic synthetic resin that is integrally formed by fusing together the joining peripheral portions of the upper shell portion and the lower shell portion that are separately molded by injection molding,
An inlet portion for injecting fuel oil into the upper shell portion is integrally formed, and an inlet on the inner surface side of the upper shell portion of the inlet portion is opened when fuel oil is injected, and fuel oil or fuel oil vapor is generated in the fuel tank. Provide a check valve to block outflow from the inside of
The inlet on the inner surface side of the upper shell portion of the inlet portion is surrounded by a steam outflow prevention wall integrally extending downward from the upper shell portion, and the length of the steam outflow prevention wall is set in the fuel tank. Extend below the level of the fuel oil when the oil is full,
The fuel tank, wherein when the check valve is opened, a tip of the check valve comes into contact with the vapor outflow prevention wall, and an opening degree of the check valve is regulated.   The check valve has an end fixed to the end of the inlet on the inner surface side of the upper shell portion, and normally closes the inlet on the inner surface side of the inlet portion of the upper shell portion by a spring and opens when fuel oil is injected. The fuel tank according to claim 1.   The said inlet part is formed in the corner part of the boundary of the upper wall of the said upper shell part, and a side wall, The said steam outflow prevention wall is formed from the upper wall of the said upper shell part to the side wall. The fuel tank as described in.   The fuel tank according to claim 1 or 2, wherein the inlet portion is formed on an upper wall of the upper shell portion, and the steam outflow prevention wall is formed of an upper wall of the upper shell portion.   The fuel tank according to any one of claims 1 to 4, wherein a protrusion that contacts the check valve when the check valve is opened is formed on a side surface of the steam outflow prevention wall.   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, and the inner resin layer is formed of high-density polyethylene (HDPE). The outer sheet layer is formed of a fuel-permeable multilayer resin sheet, and the layer in contact with the inner resin layer of the fuel-permeable multilayer resin sheet is formed of a material compatible with high-density polyethylene (HDPE). The fuel tank according to any one of claims 1 to 5.

Images