Internal-combustion engines – Charge forming device – Fuel injection system
Reexamination Certificate
2003-03-12
2004-12-14
Moulis, Thomas (Department: 3747)
Internal-combustion engines
Charge forming device
Fuel injection system
Reexamination Certificate
active
06830035
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims the benefit of priority of Japanese Patent Application No. 2002-72669 filed on Mar. 15, 2002, the content of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a structure of installing an injector in a common rail to which fuel for internal combustion engine (hereinafter called “engine”) is supplied and a method of the same.
2. Description of Related Art
As shown in
FIG. 6
, a structure of installing an injector
110
in a common rail
100
in use of a clip and a seal member
111
is well known. The common rail
100
is provided with a delivery pipe
101
extending radially outward. The injector
110
is fixed to the delivery pipe
101
. The delivery pipe
101
and the clip
120
are provided on surfaces thereof with protection layers formed by plating or coating for securing erosion resistance and enhancing strength.
For fixing the injector
110
to the delivery pipe
101
, the seal member
111
such as an O-ring and the clip
120
are mounted at first on an end portion of the injector
110
. Then, the injector
110
is inserted into an interior of the delivery pipe
101
. The delivery pipe
101
is provided at an end outer circumference thereof with a pair of projections
102
extending radially outward in opposite directions. The injector
110
is fixed to the delivery pipe
101
in such a manner that the projections
102
are snap engaged with openings
121
formed in the clip
120
, while the seal member
111
seals a clearance between an interior wall
101
a
of the delivery pipe
101
and an outer circumference of the injector
110
.
However, when the injector
110
on which the seal member
111
and the clip
120
have been mounted is inserted into the interior of the delivery pipe
101
, the projections
102
come in contact with and slide on guide plates
122
for guiding the projections
102
to the openings
121
so that the protection layers formed on the delivery pipe
101
and the clip
120
tend to be peeled off.
If a part of the protection layers is peeled off due to contact between the projections
102
and the guide plates
122
, the peeled protection layer falls down or scatters as foreign material
130
. As a result, the foreign material
130
is sometimes lodged between the seal member
111
and the interior wall
101
a
of the delivery pipe
101
, which causes the seal member
111
to seal insufficiently. Accordingly, the conventional structure of installing the injector
110
in the delivery pipe
101
has a drawback in that fuel is likely leaked from a joint portion between the injector
110
and the delivery pipe
101
.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a compact structure of installing an injector in a delivery valve with which foreign material is not lodged between a seal member and an interior wall of the delivery valve.
Another object of the present invention is to provide a simple method of installing an injector in a delivery valve with which foreign material is lodged between a seal member and an interior wall of the delivery valve.
To achieve the above object, in a structure of installing an injector in a common rail for an internal combustion engine, a delivery pipe of the common rail is provided on a surface thereof with a protection layer. A seal member is mounted on the attachment portion of the injector for sealing a clearance between an inner wall of the delivery pipe and an outer circumference of the attachment portion. A clip member has a bottom section mounted on the attachment portion on an opposite side of the seal member with respect to an axial end of the delivery pipe and a resilient sidewall section extending from outer periphery of the bottom section toward the delivery pipe and snap engaged with an outer circumference of the delivery pipe.
With the structure mentioned above, shape of the clip member is formed to satisfy a condition that, when the attachment portion on which the seal member and the clip member have been mounted is inserted into the inner wall of the delivery pipe in a state that the attachment portion is substantially axially aligned with the delivery pipe, the side wall section of the clip member comes in contact with the delivery pipe after the seal member comes in contact with the inner wall of the delivery pipe.
According to the structure mentioned above, foreign material, which is a part of the protection layer peeled off due to contact between the clip member and the delivery pipe, is not lodged between the seal member and the inner wall of the delivery pipe, since, when the clip member comes in contact with the delivery pipe, the seal member has already closely contacted the inner wall of the delivery pipe. Accordingly, the installation structure mentioned above has a superior sealing characteristic.
It is preferable that the delivery pipe is provided at an axial end outer circumference thereof with projections protruding outward and the side wall section of the clip member is provided with openings with which the projections are engaged.
With the projections and the openings, the injector is easily and confidently fixed to the delivery pipe.
A method of installing an injector in a delivery pipe of a common rail for an internal combustion engine with a resilient clip member and a seal member, where the delivery pipe is provided on a surface thereof with a protection layer and at an axial end outer circumference thereof with projections and the clip member is provided with openings, comprises the following steps.
First step is to mount the seal member and the clip member on an outer circumference of the injector so as to position the seal member on a side of an axial end of the injector with respect to the clip member. Second step is to insert the injector into the delivery pipe without causing the clip member to contact with the delivery pipe until the seal member comes in contact with an inner wall of the delivery pipe. Third step is to further insert the injector into the delivery pipe, while keeping a state that the seal member is in contact with the inner wall of the delivery pipe, so that the clip member comes in contact with the delivery pipe. Fourth step is to still further insert the injector into the delivery pipe until the projections are snap engaged with the openings.
The installation method mentioned above has an advantage of preventing the foreign material, which is a part of the protection layer peeled off due to contact between the clip member and the delivery pipe, from being lodged between the seal member and the inner wall of the delivery pipe.
REFERENCES:
patent: 4307693 (1981-12-01), Glockler et al.
patent: 5136999 (1992-08-01), Bassler et al.
patent: 5167213 (1992-12-01), Bassler et al.
patent: 5301647 (1994-04-01), Lorraine
patent: 5724946 (1998-03-01), Franchitto
patent: 6019089 (2000-02-01), Taylor et al.
patent: 6102007 (2000-08-01), Furst
patent: 6374809 (2002-04-01), Satou
patent: 6705292 (2004-03-01), Bugos
patent: 2004/0055578 (2004-03-01), Scollard et al.
Nishiwaki Toyoji
Oomori Ryutaro
DENSO Corporation
Moulis Thomas
Nixon & Vanderhye PC.
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