Metal working – Method of mechanical manufacture – Gas and water specific plumbing component making
Reexamination Certificate
2002-03-18
2004-07-06
Omgba, Essama (Department: 3726)
Metal working
Method of mechanical manufacture
Gas and water specific plumbing component making
C029S522100, C029S890142, C072S370030, C072S370100
Reexamination Certificate
active
06757974
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a fuel inlet for pouring fuel into a fuel tank of a car and the like, and a manufacturing method thereof.
BACKGROUND OF THE INVENTION
Generally, when pouring fuel such as gasoline into a fuel tank of a car and the like, a fuel inlet
701
as shown in
FIG. 31
is used. A connecting pipe J is fixed to the end of the fuel inlet
701
on the fuel tank side, and a breather tube
703
communicating with the fuel tank T is provided in the vicinity of a fuel port
701
a
of the fuel inlet
701
. At the time of fueling, a not shown fuel feeding nozzle is inserted into the fuel inlet
701
through the fuel port
701
a
and fuel is fed into the fuel tank T through the fuel inlet
701
and the connecting pipe J. When fuel feed into the fuel tank T starts, the air in the fuel tank T is pushed toward the fuel port
701
a
of the fuel inlet
701
through the breather tube
703
. When fuel feed continues and a certain amount of the fuel is stored in the fuel tank T, the internal pressure of the fuel tank T increases and causes the fuel feed nozzle to automatically stop, and further automatic feeding is impossible. A person who feeds fuel notices it and shifts the feeding into manual operation, and additionally pours a small amount of gasoline two to three times before finishing the feeding.
The above process involves a problem that since the air pushed toward the fuel port while the feeding contains a high density of fuel vapor, careless emission thereof into the atmosphere leads to an increase of fuel density around and thus unfavorable effects on the environment.
To solve this problem, it is proposed to employ a fuel inlet
801
shown in FIG.
32
. The fuel inlet
801
is provided with a relatively small diameter portion
806
within its fuel passage. Since a space
807
shown in cross section of the passage, when fuel fed at a specific rate passes the relatively small diameter portion
806
, is made smaller than in a conventional fuel inlet, venturi vacuum is generated and negative pressure in the space
807
is increased. As a result, the air returning toward the fuel port from the fuel tank through the breather tube
803
is effectively prevented from being emitted into the atmosphere. This is called a liquid seal, which is one of the means in Onboard Refueling Vapor Recovery systems, or ORVRs.
However, if the fuel inlet
801
having a relatively small diameter portion
806
of &phgr;25.4 mm, for example, is produced as a solid one by pressing a blank pipe instead of connecting a plurality of members, one end of the blank pipe of &phgr;25.4 mm, i.e. the fuel port should be expanded to &phgr;48 mm to 60 mm, and such a large expansion often causes cracking. Also it is required that the breather tube
803
and the inlet pipe
802
be connected easily and securely and that a spiral groove be easily formed around the expanded end of the inlet pipe to allow a cap to be screwed thereon.
A fuel inlet, having a double structure in the vicinity of the fuel port formed by folding one end of the pipe inward, is known as disclosed in the Publication of Japanese Unexamined Patent Application No. 9-39591(Cf. FIG.
33
B). This type of fuel inlet
901
obtains enough strength because of the double structure in the vicinity of the fuel port and has a great durability against abrasion due to opening/closing operation of the fuel port cap.
The above fuel inlet
901
is formed as follows: Firstly, as shown in
FIG. 33A
, a first taper portion
901
a
and a second taper portion
901
b
are formed. Secondly, the first taper portion
901
a
and the second taper portion
901
b
are folded back to the inside of the pipe (See dotted lines in
FIG. 33A
) by applying pressure P in the axial direction onto the open end of the second taper portion
901
b
. Then, the folded end is expanded and a groove
901
c
is formed. By forming the first taper portion
901
a
and the second taper portion
901
b
having different cone angles, respectively, and folding these taper portions, the bending region can be prevented from being applied an excessive load thereto.
Although the fuel inlet
901
, wherein a double structure is provided in the vicinity of the fuel port by folding back the end of the pipe, is quite useful, it involves a problem that the manufacturing process thereof is complicated. These days a fuel inlet is sometimes provided with a retainer having an interference portion, but it makes the manufacturing process further complicated to produce such an inlet according to the method disclosed in the Publication of Japanese Unexamined Patent Application No. 9-39591. Attaching a separate retainer to the folded end is practical, and a synthetic resin retainer which is usually more expensive than a metal one is fixed in because it is difficult to attach a metal retainer to the folded end by crimping or welding.
Also known is a structure, as shown in
FIG. 34
, wherein a fuel inlet
1001
is forced and fixed into a fuel inlet supporting hole
1015
provided in a car body B (See Publication of Japanese Examined Utility Model Application No. 6-259, for example). Specifically, the fuel inlet
1001
having a synthetic resin cylindrical cover
1005
fitted on the outer circumference in the vicinity of the fuel port is forced into the fuel inlet supporting hole
1015
from the side of a fuel tank T, thereby the cylindrical cover
1005
is pressed against the fuel inlet supporting hole
1015
. Since this structure enables relative movement between the car body B and the fuel inlet
1001
, even if a heavy load is applied to the car body B, for example, the car body B yields or bulges independently of the fuel inlet
1001
, and therefore the heavy load does not directly affect the fuel inlet
1001
. Furthermore, even if the car body B is deformed to bulge toward the fuel inlet
1001
, the bulging region does not cause the fuel port cap C to be pushed up and removed because the outer diameter of the fuel port cap C is designed to be smaller than the outer diameter of the cylindrical cover
1005
.
The structure in
FIG. 34
, however, has a problem that the cylindrical cover
1005
made of synthetic resin leads to the higher cost of materials, which makes the cost for fixing the fuel inlet
1001
increased. Also, the cylindrical cover
1005
used as a separate member needs to be produced separately as well as requires another process step of attaching the same to the fuel inlet
1001
, and as a result the cost for fixing the fuel inlet
1001
is further increased.
Moreover, this structure requires a retaining mechanism for preventing the cylindrical cover
1005
from being displaced axially relative to the fuel inlet
1001
when the fuel inlet
1001
with the cylindrical cover
1005
wrapped therearound is forced into the fuel inlet supporting hole
1015
. Specifically, as shown in
FIG. 34
, the retaining mechanism is constituted by a bead
1001
a
provided on the outer circumference of the fuel inlet
1001
and a groove
1005
a
provided on the internal circumference of the cylindrical cover
1005
for catching the bead
1001
a
. This type of retaining mechanism complicates the structure of the fuel inlet
1001
and impedes production thereof.
SUMMARY OF THE INVENTION
Wherefore, a principal object of the present invention is to provide a fuel inlet which has a liquid seal function and whose production requires only a small number of parts and also is easy.
Another object of the present invention is to provide a fuel inlet which has a double structure in the vicinity of its fuel port and is easy to make.
Further object of the present invention is to provide a fuel inlet having a simple structure and not requiring high cost of fixing the same to a car body such that relative movement is allowed therebetween.
According to the first phase of the present invention, the fuel inlet comprises: an inlet pipe for guiding fuel into a fuel tank and a breather tube for letting the air out of the fuel tank toward the forward end portion of the inlet pipe while feeding fuel, one end of the
Kawabe Toyohisa
Kido Tsuguo
Nakada Yuji
Omori Tetsuji
Sugiura Masayuki
Davis & Bujold PLLC
Futaba Industrial Co. Ltd.
Omgba Essama
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