Metal deforming – By extruding through orifice – Utilizing internal forming means
Reexamination Certificate
2001-12-27
2004-08-17
Tolan, Ed (Department: 3725)
Metal deforming
By extruding through orifice
Utilizing internal forming means
C072S467000
Reexamination Certificate
active
06776019
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an extrusion die for manufacturing a metal hollow member such as an aluminum hollow member, a mandrel for the extrusion die, and a male die for the extrusion die.
2. Description of Related Art
For example, as shown in
FIG. 14
, a conventional extrusion die for manufacturing a hollow member
1
(see
FIG. 13
) includes a male die
101
for forming hollow portions
1
a
of the hollow member
1
and a female die
102
for forming the external peripheral portion of the hollow member
1
. The female die
102
is fitted in an annular base portion
103
of the male die
101
.
The male die
101
includes the aforementioned annular base portion
103
and a bridge portion
104
formed on the rear face (i.e., upstream-side surface) of the annular base portion
103
. The bridge portion
104
includes a mandrel holding slit
105
extending in the fore-and-aft direction at the central portion thereof. Into this mandrel holding slit
105
, a mandrel
108
having a mandrel main portion
106
with comb-shaped forming protrusions
107
is inserted from the rear side of the mandrel holding slit
105
and held therein. The female die
102
having a forming aperture
109
penetrated in the fore-and-aft direction of the female die
102
is fitted in a fitting aperture
110
formed in the axial center of the annular base portion
103
to be connected with the male die
101
concentrically. Thus, the forming gap
111
corresponding to the cross-section of the hollow member
1
to be extruded is formed between the forming protrusions
107
and the female-die forming aperture
109
.
The forming protrusions
107
of the mandrel
108
are required to have such hardness that can bear high extrusion pressure at the time of extrusion. Accordingly, the forming protrusions
107
are usually made of super-hard material such as cemented carbide or ceramics and formed by an electric-spark forming method.
In a conventional die, however, since the forming protrusions
107
of the mandrel
108
are integrally formed at the tip of the mandrel main portion
106
, the whole mandrel is made of super-hard material, resulting in an expensive component.
Furthermore, since the forming protrusions
107
are integrally formed on the mandrel main portion
106
, damage of the forming protrusions
107
causes an exchange of the entire mandrel
108
, causing increased running costs.
For example, in order to increase the number of hollow portions of the hollow member arranged side by side, it is necessary to increase the number of the forming protrusions
107
formed on the tip portion of the mandrel main portion
106
or decrease the thickness of each forming protrusion
107
. However, there was a limitation to give further precise processing to the tip portion of the mandrel main portion
106
.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an extrusion die for a hollow member which can decrease the costs for manufacturing the hollow member and for maintaining the extrusion die and can easily cope with more precise processing.
It is another object of the present invention to provide a mandrel for the aforementioned extrusion die.
It is still another object of the present invention to provide a male die for the aforementioned extrusion die.
According to the first aspect of the present invention, an extrusion die for a hollow member, comprises: a male die for defining a plurality of hollow portions of the hollow member, the male die including an annular base portion and a bridge portion bridging the annular base portion; a female die for defining an outer peripheral portion of the hollow member; and a mandrel having a plurality of forming protrusions, the mandrel being inserted and held in a mandrel holding slit formed in a center of the bridge portion in a fore-and-aft direction, wherein the mandrel includes a mandrel main portion divided into a plurality of divided members and a plurality of rigid pins each arranged in a fore-and-aft direction of the mandrel main portion, and wherein the plurality of rigid pins are pinched by and between the divided members of the mandrel main portion with tip portions of the plurality of rigid pins protruding from a front end of the mandrel main portion, whereby the plurality of tip portions constitute the plurality of forming protrusions.
With this extrusion die, the mandrel main portion is divided into a plurality of divided members and the rigid pins are pinched by and between the divided members with tip portions of the rigid pins forming the forming protrusions protruding from a front end of the mandrel main portion. Accordingly, the mandrel main portion can be made of relatively cheap hard material such as die steel by employing the rigid pins made of super-hard materials. This decreases the entire costs for the mandrel.
According to the second aspect of the present invention, a mandrel for use in an extrusion die for extruding a hollow member, the mandrel comprises: a mandrel main portion which is divided into a plurality of divided members; and a plurality of rigid pins each disposed in a fore-and-aft direction of the mandrel main portion, wherein the plurality of rigid pins are pinched by and between the divided members of the mandrel main portion with tip portions of the plurality of rigid pins protruding from a front end of the mandrel main portion, whereby the plurality of rigid pins constitute forming protrusions.
With this mandrel, it is possible to properly perform precise processing of the hollow member by the extrusion die.
According to the third aspect of the present invention, a male die for an extrusion die, wherein the male die defines a plurality of hollow portions of a hollow member and is combined with a female die defining an outer peripheral configuration of the hollow member, the male die comprises: an annular base portion; a bridge portion bridging the annular base portion; and a mandrel having a plurality of forming protrusions, the mandrel being inserted and held in a mandrel holding slit formed in a center of the bridge portion in a fore-and-aft direction, wherein the mandrel includes a mandrel main portion divided into a plurality of divided members and a plurality of rigid pins each arranged in a fore-and-aft direction of the mandrel main portion, and wherein the rigid pins are pinched by and between the divided members of the mandrel main portion with tip portions of the rigid pins protruding from an front end of the mandrel main portion, whereby the tip portions constitute the forming protrusions.
This male die can constitute the aforementioned extrusion die.
Other objects and the features will be apparent from the following detailed description of the present invention with reference to the attached drawings.
REFERENCES:
patent: 5572894 (1996-11-01), Yano
patent: 6351979 (2002-03-01), Inamura et al.
Tolan Ed
Yugen Kaisha Yano Engineering
LandOfFree
Extrusion die for hollow member, mandrel for said extrusion... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Extrusion die for hollow member, mandrel for said extrusion..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Extrusion die for hollow member, mandrel for said extrusion... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3274800