Pipe joint with enlarged metal pipe and method for...

Pipe joints or couplings – Packed – Flanged pipe

Reexamination Certificate

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Details

C285S382400

Reexamination Certificate

active

06328351

ABSTRACT:

CROSS REFERENCE TO RELATED APPLICATION
This application is based upon and claims the benefit of priority of Japanese Patent Applications No. H.10-211442 filed on Jul. 27,1998, the contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a pipe joint, a metal pipe with a flange to be joined to a base member and a method for manufacturing the same, in particular, applicable to refrigerant piping or hot water piping in an air conditioner for vehicles.
2. Description of Related Art
Conventionally, a pipe joint described in JP-A-8-247357 is well known. According to the conventional pipe joint, a flange member
20
is provided with an installation bore
26
, the inner diameter of which is gradually reduced from one end
20
b
toward the other end
20
a,
as shown in FIG.
7
. After inserting a pipe
10
into the installation bore
26
, a mandrel
80
is placed inside the pipe
10
to prevent the deformation of the inside of the pipe
10
, as shown in FIG.
8
. Then, the pipe
10
is pressed in an axial direction from both sides with a given clamp mechanism (not shown), as if the flange member
20
is sandwiched, as shown by an arrow
81
. When the pipe
10
is pressed as mentioned above, the diameter of the pipe
10
is partly enlarged to fill a clearance B (refer to
FIG. 7
) between the inside surface of the installation bore
26
and the outside surface of the pipe
10
, and a bulging portion
16
of the pipe
10
is formed at a position just behind an end surface
20
a
of the flange member
20
.
As a next step, an axial pressing force is applied to the pipe
10
from the direction shown by an arrow
82
in
FIG. 9
with another given clamp mechanism (not shown). Therefore, the bulging portion
16
is further crushed in an axial direction to form a final shape thereof.
Further, when an axial pressing force is applied to the pipe
10
from the direction shown by an arrow
83
in
FIG. 10
with a further given clamp mechanism (not shown), the end of the pipe
10
is radially expanded. As a result, an enlarged pipe opening
17
is formed and also a groove
18
for storing an O ring
13
is formed between the enlarged pipe opening
17
and the bulging portion
16
.
FIG. 11
shows an embodiment of the pipe joint manufactured as mentioned above, in which the O ring
13
is stored in the groove
18
and a periphery portion (
16
,
17
and
18
) of the pipe
10
is inserted into an opening
32
of a joint base member
30
(joint opponent member) to connect the pipe
10
to the opening
32
.
According to the conventional embodiment mentioned above, the force for joining the pipe
10
with the flange member
20
is relatively weak because the pipe
10
is not sufficiently pressed to the inside surface of the installation bore
26
, as the inside of the pipe
10
is merely expanded by the pressing force toward the axial direction to the pipe
10
.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above mentioned problem, and an object of the present invention is to provide a pipe joint in which the force for joining a metal pipe with a flange member is stronger and a method for manufacturing the pipe joint. To achieve the above object, a metal pipe
10
is provided with a first enlarged portion
11
inserted to an opening
32
of a joint base member
30
. The pipe
10
is firmly fixed with the joint base member
30
through a flange member
20
. The pipe
10
is further provided with a second enlarged portion
14
, a bulging portion
15
and an extending portion
19
.
The second enlarged portion
14
is formed by drawing an enlargement punch
70
through the inside of the pipe
10
to expand the inside diameter of the pipe
10
after the pipe
10
is inserted into an installation bore
22
of the flange member
20
. Therefore, the inside diameter of the second enlarged portion becomes larger than that of the other part of the pipe
10
and the second enlarged portion
14
is radially and rigidly pressed against substantially the entire inside surface of the installation bore
22
.
The bulging portion
15
is formed by making a part of the outer circumference surface of the pipe
10
swell, preferably, at the same time when the second enlarged portion
14
is formed. The bulging portion
15
is rigidly pressed against an end surface
20
b
of the flange member
20
and serves to prevent the axial direction movement of the pipe
10
. A remaining part of the pipe
10
is the extending portion
19
.
It is another aspect of the present invention to provide an uneven surface
24
like a knurling surface at the inside of the installation bore
22
so that the outer circumference surface of the second enlarged portion
14
may be formed into the uneven surface of the installation bore
22
when the pipe
10
is radially expanded by the punch
70
. Therefore, the force of joining the pipe
10
with the flange member
20
becomes stronger.
It is a further aspect of the present invention to provide a cylindrical holding surface
25
at the inside of the installation bore
22
so that the outer circumference surface of the second enlarged portion
14
may be uniformly pressed against the inner circumference of the cylindrical holding surface
25
. Thus, the cylindrical holding surface
25
serves not to form a gap between the pipe
10
and the flange member
20
, through which fluid such as water may pass.


REFERENCES:
patent: 4130932 (1978-12-01), Epmeier
patent: 4142843 (1979-03-01), Kish
patent: 5810054 (1998-09-01), Goulet
patent: 5853201 (1998-12-01), Izumi et al.
patent: 6016843 (2000-01-01), Wada et al.
patent: 0 791 776 A1 (1997-08-01), None
patent: A-8-247357 (1996-09-01), None

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