U.S. patent application number 10/588977 was filed with the patent office on 2007-12-06 for method and tool for closed die forging.
Invention is credited to Trygve Ruste.
Application Number | 20070277579 10/588977 |
Document ID | / |
Family ID | 34793420 |
Filed Date | 2007-12-06 |
United States Patent
Application |
20070277579 |
Kind Code |
A1 |
Ruste; Trygve |
December 6, 2007 |
Method And Tool For Closed Die Forging
Abstract
A press tool for closed die forging a blank into a product is
described. Said tool including upper and lower centre members and
first and second side members. Said members define a cavity with
the form of the product. In a two-step closed die forge process the
blank is placed between said upper and lower centre members. The
first and second side members are forced against the blank
horizontally upsetting the outer edges of the blank. Then, the
centre members are forced vertically into the blank, until the
material in the blank has substantially filled the cavity.
Inventors: |
Ruste; Trygve; (Raufoss,
NO) |
Correspondence
Address: |
Timothy J. Keefer;SEYFARTH SHAW
55 E. Monroe Street
Chicago
IL
60603-5863
US
|
Family ID: |
34793420 |
Appl. No.: |
10/588977 |
Filed: |
February 14, 2005 |
PCT Filed: |
February 14, 2005 |
PCT NO: |
PCT/NO05/00054 |
371 Date: |
July 2, 2007 |
Current U.S.
Class: |
72/355.6 |
Current CPC
Class: |
B21J 5/02 20130101 |
Class at
Publication: |
072/355.6 |
International
Class: |
B21J 13/00 20060101
B21J013/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 12, 2004 |
NO |
20040634 |
Claims
1. A method for closed die forging a product from a preform blank
of a forgeable material, characterized in placing the blank in a
press tool, said press tool including a number of centre and side
members surrounding the blank, closing the press tool upon the
blank, by vertically clamping the blank between an upper and lower
centre member, horizontally moving first and second side members
synchronously towards said centre members centring the blank in the
press tool, upsetting the outer parts of said blank with the first
and second said members in a continuation of said horizontal
movement, forcing the upper and lower centre members into the blank
until the material of the blank fills a cavity defined by said
centre and side members, by which the blank is forged with short
horizontal and vertical movements of the tool avoiding large
horizontal movements in the material.
2. (canceled)
3. (canceled)
4. A tool for forging a blank into a product with the method
claimed in claim 1, wherein the tool includes a number of upper and
lower centre members, and first and second side members, said first
and second side members enclosing said upper and lower centre
members defining a closed cavity with the form of product, said
first and second side members being adapted to upset outer parts of
the blank in short horizontal movements, the upper and lower centre
members being adapted to be forced into the blank causing it to
fill said closed cavity.
5. A tool as claimed in claim 4, wherein first and second side
members having sloping outer surfaces, a number of press members
with mating inner surfaces acting on said first and second side
members in order to force said first and second side members
together.
6. A tool as claimed in claim 5, wherein first and second side
members comprising upper and lower parts.
7. A tool as claimed in claim 4, wherein first and second side
members including brake surfaces forming a gutter.
8. (canceled)
Description
FIELD OF THE INVENTION
[0001] The present invention relates to closed die forging in
general and in particular the forging of wheel suspension safety
elements in aluminium, for the automobile industry.
TECHNICAL BACKGROUND
[0002] The common method for closed die forging aluminium is
inherited from classical steel forging. Two dies are mounted in a
press, and are pressed vertically against each other impressing
their form on a blank that lies there between. Each die includes a
negative half imprint of the form of the finished product milled
into the die material; the dimension of the imprint being corrected
for the temperature of the blank and die tool. A brake surface is
milled along the rim of each half form. When the die tools are
pressed against each other to the end position, these brake
surfaces form a gap or gutter of minimum 3 mm. The forge process is
"kneading" the material, and properly executed it will provide a
high strength aluminium alloy with very high endurance strength.
Thus, forging is particularly suited for highly stressed
components, e.g. in the wheel suspension of a car.
[0003] The classical forging process has four main drawbacks:
[0004] 1. Comparatively large consumption of materials (much
waste). The pressure build up in order to fill the tool form is
created by braking the material in the gutter. The gutter is
integrated into the die tool, and follows the movement of the dies.
Thus, initially the gutter forms a very large gap. The large gap
will allow an easy flow of material through the gutter. Only at the
end of the press stroke sufficient pressure is created to fill the
form. Waste of 30% is considered a very good result (weight of
waste material compared with the weight of the finished
product).
[0005] 2. The press force requirements are large. At the end of the
press stroke, a large total working area (the surface of the
product in addition to the area of the gutters) must be put under
sufficient pressure to get the material flowing out of the gap
between the dies.
[0006] 3. Requirements for special lubrication fluids, in
relatively large volumes. The material is squeezed from the centre
of the tool and out through the brake gap/gutter with a steadily
increasing pressure. There are large horizontal movements of
material along the tool surfaces, which must be lubricated with
special lubricating fluids in relatively large quantities.
[0007] 4. The demanding requirements for centring the blank. A
prerequisite for the process is that the material should flow
freely in all directions. Thus, it is not possible to place
stoppers/orienting pins in the tool. The blank must therefore be
placed accurately in the press, e.g. with a robot.
BRIEF SUMMARY OF THE INVENTION
[0008] It is an object of the present invention to provide a method
and tool for closed die forging with less waste of raw materials
compared with prior art methods.
[0009] Another object is to provide a method and tool for closed
die forging which requires less press force.
[0010] Still another object is to provide a closed die forging
method and tool in which large horizontal flow of material is
avoided, thus making the requirements on lubrication less
stringent.
[0011] Yet still another object is to provide a method and tool for
closed die forging in which the blank is more or less self centring
in the press.
[0012] These objects are achieved in a method and tool according to
the appended patent claims. In particular the method includes
closed die forging a product from a preform blank of a forgeable
material by placing the blank in a press tool, said press tool
including a number of centre and side members surrounding the
blank, closing the press tool upon the blank, and forging the blank
with short horizontal and vertical movements of the tool avoiding
large horizontal movements in the material.
[0013] The tool for forging a blank into a product according to the
method in claim 1 includes a number of upper (21) and lower (22)
centre members, and first (23, 24) and second (25, 26) side
members, said first (23, 24) and second (25, 26) side members
enclosing said upper (21) and lower (22) centre members defining a
closed cavity with the form of product.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The invention will now be described in detail in reference
to the appended drawings, in which
[0015] FIG. 1 is an illustration of a classical forge process
according to prior art, shown in four subsequent steps,
[0016] FIG. 2 is an illustration of the inventive forge process,
shown in three individual steps,
[0017] FIG. 3A-C shows details of the inventive forge process,
[0018] FIG. 4 shows a detail of the corresponding process of
forging components of large width,
[0019] FIG. 5 shows typical cross sections of components
manufactured with the new process and the prior art process.
DETAILED DESCRIPTION OF THE INVENTION
[0020] The classical prior art forging process is illustrated in
FIG. 1. In the first step, FIG. 1A, a preform blank is placed
between the dies of a press. When force is applied, FIG. 1B, the
material in the blank will start to fill the form of the dies. Some
material will flow horizontally out of the die tool. FIG. 1C shows
how this process continues as the die tool closes. At the end of
the press stroke, FIG. 1D, the material of the blank fills the die
form completely, with a rim of superfluous material protruding out
of the gutter. In a subsequent step, this rim is removed. The
amount of material that must be removed, can be equal to the weight
of the finished article, i.e. 50% of the material in the preform
blank is wasted.
[0021] In the new, inventive forge process, illustrated in FIG.
2A-C, a redesigned forge tool is used. The tool includes an upper
21 and lower 22 centre member, and first 23, 24 and second 25, 26
side members. Each side member consists of an upper part 23, 25 and
a lower part 24, 26. The side members are equipped with a sloping
outer surface. Two press members 27 and 28 having mating sloping
surfaces are acting on the side members. When moving the press
members vertically, their movement is translated into a
corresponding horizontal movement of the side members. In the
horizontal plane, the forms of the inner surface of each side
member will closely follow the forms of the upper and lower centre
members. Thus, when the side members are brought completely
together, the tool will form a closed unit. The whole assembly
rests on a table 29.
[0022] Initially, the blank 20 is placed between the centre members
21, 22 clamping the blank in position. Then, the side members 23,
24 and 25, 26 are closed upon the blank. By this arrangement, it is
not necessary to place the blank with great precision, as the tool
itself will align the blank in a correct position when the side
members close upon it.
[0023] In the first forge step, FIG. 2B, the press members 27, 28
are forced downwards until they butt against the table 29. This
results in a horizontal movement of the side members, which will
upset the ends of the blank. The side members will close against
the centre members. The material in the blank is pressed
horizontally from the ends into the die form, which will become
about 2/3 filled.
[0024] Synchronously, or when the horizontal movement is finished,
the centre members are forced together squeezing until the material
has filled the rest of the form. This step is illustrated in FIG.
2C. Due to the small width of the centre members, a relatively
small press force is required compared with the prior art forge
method.
[0025] In this embodiment of the inventive forge process, a small
fixed brake gap may be employed, in the range of 0.5-1.0 mm. The
brake gap is mainly included in order to allow the form to be
filled completely, while taking care of small differences in the
volume of the blank. The amount of waste material is negligible.
However, an additional step is needed for removing the rim of waste
material.
[0026] In the embodiment shown in FIG. 3 A-C, the brake gap is
dispensed with altogether. The figures show only a detail of the
tool.
[0027] In FIG. 3A, the tool has just been closed. The side member
includes no gutter, and is shaped like a blunt wedge. When force is
applied this blunt wedge will engage the blank; the blank will
become upset at the rim and start filling the cavity in a proper
way, as illustrated in FIG. 3B. In FIG. 3B the horizontal movements
have been completed. The material in the blank has been upset at
the rim, and now partially fills the cavity formed by the side
members. By using side member of this particular shape, one is
assured that the blank is upset at the correct place. Else, the
upsetting action could start at any point along the blank, e.g. in
the middle, preventing the material filling the cavity as it
should.
[0028] In FIG. 3C also the vertical movements have been completed.
The material from the blank now nearly completely fills the cavity.
Only small interstices remain. Tolerances as to the volume of the
blank will be taken care of by these voids.
[0029] In case the width of the product exceeds about 30 mm, the
centre members must be divided into several sub-members, as
illustrated in FIG. 4. Thus, the central part of the product will
form ribs or a honeycomb pattern in order to achieve sufficient
"kneading" without large horizontal movements of material during
the second step of the forging process. The figure shows a detail
of the finished product.
[0030] In FIG. 5 is shown typical sections from a broad component
forged according to the classical method (right; rim of waste
material removed), and according to the new inventive method
(left).
* * * * *