Metal deforming – Process – Tube making or reshaping
Reexamination Certificate
2001-02-20
2003-03-11
Larson, Lowell A. (Department: 3725)
Metal deforming
Process
Tube making or reshaping
C072S316000, C072S358000
Reexamination Certificate
active
06530256
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an expanded tube processing method and an expanded tube processing apparatus of a cylindrical tube.
RELATED ART
There has been heretofore a case in which an expanded tube portion having an axis inclined with respect to a tube axis of a cylindrical tube (tube) is formed on an end of the cylindrical tube (tube) of a metal.
For example, in an exhaust tube in automotive parts and the like, in order to secure a path in a limited space under a vehicle floor, as shown in
FIG. 18
, one tube
101
is connected to another tube
102
at a reduced diameter portion
103
in such a manner that a tube axis B of another tube
102
is inclined with respect to a tube axis A of the one tube
101
. When such a connection is performed, for example, as shown in
FIG. 19
, there may be used such a connection tube that a gradually changing portion
105
is formed at a tip end of a rare tube
104
of a cylindrical tube consisted of a metal tube by expanding the tube, and an expanded tube portion
106
for connection is continuously formed at the tip end of the gradually changing portion
105
, tube axes C, B of the gradually changing portion
105
and the expanded tube portion
106
are inclined with respect to the tube axis A of the rare tube
104
.
Additionally, a gradually changing portion
107
may be integrally formed beforehand on a side opposite to the expanded tube portion
106
in the rare tube
104
as shown in FIG.
18
.
FIGS. 20 and 21
discussed below were developed by the present inventors in the process of inventing the method and apparatus of the present invention.
Moreover, a process is considered in which a usual punch is utilized in a method of molding the gradually changing portion
105
and expanded tube portion
106
with the inclined tube axes on the tip end of the rare tube
104
. Specifically, as shown in
FIG. 20
, considered is the process comprising: molding an enlarged diameter portion
105
a
concentric with the tube axis A of the rare tube
104
beforehand on the end of the rare tube
104
; holding and fixing a work W formed of the rare tube
104
and enlarged diameter portion
105
a
with a forming die
108
in such a manner that the tube axis A slopes with respect to a vertical line B as shown in
FIG. 20
; simply lowering a punch
110
with an inner die surface
109
formed on a lower surface thereof only in a vertical direction to insert the punch into the enlarged diameter portion
105
a
; and using the inner die surface
109
and an outer die surface
111
of the forming die
108
to press-mold the enlarged diameter portion
105
a
on the gradually changing portion
105
and expanded tube portion
106
inclined with respect to the tube axis A.
However, according to this process, as shown in
FIG. 21
, the inner die surface
109
of the punch
110
is provided with a portion
109
a
which interferes with an opening end surface
105
b
of the enlarged diameter portion
105
a
, and the enlarged diameter portion
105
a
collapses and causes a problem that an expanded tube processing is not established.
In order to prevent the aforementioned interference, it is also proposed to utilize a known slant cutting die as shown in FIG.
22
. This process comprises the steps of: forming a slant hole
202
in a punch guide
201
; disposing a punch
203
in the slant hole
202
in a slidable manner and also disposing a return spring
204
; striking a head of the punch
203
with a cam block
205
to move the punch
203
in a slant downward direction; and piercing an inclinedly disposed work
206
.
When this process is applied to an enlarged diameter processing of the gradually changing portion
105
and expanded tube portion
106
, no interference problem described with reference to
FIG. 21
occurs. However, the large punch guide
201
is necessary and this is uneconomical. Furthermore, every time differences in a tube axis angle and an expanded tube shape between the gradually changing portion
105
and the expanded tube portion
106
are handled, a new punch guide
201
needs to be provided, which causes a problem that installation expenses also increase.
If the aforementioned conventional apparatus is utilized to form the gradually changing portion and expanded tube portion inclined with respect to the tube axis of the rare tube, the aforementioned respective problems occur. There have been demanded an expanded tube processing method and apparatus which can subject the inclined gradually changing portion and expanded tube portion to the expanded tube processing with a simple constitution.
DISCLOSURE OF THE INVENTION
Wherefore, an object of the present invention is to provide an expanded tube processing method and an expanded tube processing apparatus in which an expanded tube portion provided with a tube axis having an angle with respect to a tube axis of a rare tube can be processed with good precision.
In order to solve the aforementioned problems, according to a first aspect of the present invention, there is provided an expanded tube processing method of a cylindrical tube in which a punch is disposed on the side of an opening end of a work formed of a metal cylindrical tube and the punch is inserted from the opening end of the work to enlarge the diameter of an end of the work, the method comprising steps of: inserting the punch from the opening end of the work at a predetermined angle with respect to a tube axis of the work; and moving the punch and/or the work during insertion of the punch in a direction substantially crossing at right angles to a punch insertion path to perform an expanded tube processing.
In the expanded tube processing method according to the present invention, a work opening end surface on the side of insertion of the punch may also be formed to be substantially at right angles to the insertion path of the punch.
Moreover, in the expanded tube processing method according to the present invention, the work may be inclined and held with respect to the vertical direction, the insertion path of the punch is vertical, and movement of the punch and/or the work in the direction substantially crossing at right angles to the work insertion path can be a movement of a horizontal direction.
Furthermore, in the expanded tube processing method according to the present invention, the movement of the direction substantially crossing at right angles to the punch insertion path in the punch and/or the work may also be performed in at least two directions.
Moreover, in order to solve the aforementioned problems, according to a second aspect of the present invention, there is provided an expanded tube processing apparatus of a cylindrical tube, in which a punch is disposed on the side of an opening end of a work formed of the cylindrical tube of a metal and the punch is inserted from the opening end of the work to enlarge the diameter of an end of the work, the apparatus comprising: a forming die for holding the work in an inclined state with respect to a punch insertion path; driving means for moving the punch in a direction of the insertion path; and a support mechanism for supporting the punch and/or the work in a direction substantially crossing at right angles to the insertion path of the work in such a manner that floating is possible.
Furthermore, in the expanded tube processing apparatus according to the present invention, a work opening end surface on the side of insertion of the punch may also be formed to be substantially at right angles to the insertion path of the punch.
Additionally, in the expanded tube processing apparatus according to the present invention, the forming die for the work is formed to incline and hold the work with respect to a vertical direction, the insertion path of the punch is set in a vertical direction, and a floating direction of the punch and/or the work can also be set to a horizontal direction.
Moreover, in the expanded tube processing apparatus according to the present invention, the floating direction of the punch and/or the work may also be set to at least two directions.
A
Hayakawa Hisashi
Irie Tohru
Morikawa Akinobu
Larson Lowell A.
Sango Co. Ltd.
Stevens Davis Miller & Mosher LLP
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