U.S. patent application number 14/489014 was filed with the patent office on 2015-03-19 for thermoforming tool with distinct cooling feature.
This patent application is currently assigned to Benteler Automobiltechnik GmbH. The applicant listed for this patent is Benteler Automobiltechnik GmbH. Invention is credited to Friedrich Bohner, Jochen Dorr, Christian Hielscher, Christoph Nitschke.
Application Number | 20150075246 14/489014 |
Document ID | / |
Family ID | 51609915 |
Filed Date | 2015-03-19 |
United States Patent
Application |
20150075246 |
Kind Code |
A1 |
Dorr; Jochen ; et
al. |
March 19, 2015 |
THERMOFORMING TOOL WITH DISTINCT COOLING FEATURE
Abstract
A tool for hot forming and press hardening a steel structure
includes an upper tool and a lower tool, each having a base body
made of highly heat conductive material and comprised of at least
two segments. The base body of at least one of the upper and lower
tools has a cooling channel. Arranged on the base body of at least
one of the upper and lower tools is a wear protection shield.
Inventors: |
Dorr; Jochen; (Bad Driburg,
DE) ; Nitschke; Christoph; (Paderborn, DE) ;
Bohner; Friedrich; (Oerlinghausen, DE) ; Hielscher;
Christian; (Delbruck, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Benteler Automobiltechnik GmbH |
Paderborn |
|
DE |
|
|
Assignee: |
Benteler Automobiltechnik
GmbH
Paderborn
DE
|
Family ID: |
51609915 |
Appl. No.: |
14/489014 |
Filed: |
September 17, 2014 |
Current U.S.
Class: |
72/347 ;
72/343 |
Current CPC
Class: |
B21D 22/22 20130101;
B21D 22/208 20130101; C21D 9/48 20130101; B21D 22/201 20130101;
C21D 2221/00 20130101; B21K 7/00 20130101; B21D 37/16 20130101;
C21D 1/673 20130101; B21D 22/022 20130101 |
Class at
Publication: |
72/347 ;
72/343 |
International
Class: |
B21K 7/00 20060101
B21K007/00; B21D 22/20 20060101 B21D022/20; B21D 37/16 20060101
B21D037/16; B21D 22/22 20060101 B21D022/22 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 18, 2013 |
DE |
10 2013 110 299.9 |
Claims
1. A tool for hot forming and press hardening a steel structure,
said tool comprising: an upper tool and a lower tool, each having a
base body made of highly heat conductive material and comprised of
at least two segments, wherein the base body of at least one of the
upper and lower tools has a cooling channel; and a wear protection
shield arranged on the base body of at least one of the upper and
lower tools.
2. The tool of claim 1, wherein the base body is made of a light
metal alloy.
3. The tool of claim 2, wherein the light metal alloy is an
aluminum alloy.
4. The tool of claim 1, wherein the cooling channel is formed as a
throughbore extending through the base body.
5. The tool of claim 4, wherein the throughbore extends in a
straight line.
6. The tool of claim 1, further comprising a temperature control
unit configured to maintain the segments at different
temperatures.
7. The tool of claim 6, wherein the temperature control unit
includes heating elements provided in at least one of the
segments.
8. The tool of claim 1, wherein the segments are arranged in
spaced-apart relation to define a separation gap which extends in
orthogonal relation to the wear protection shield.
9. The tool of claim 1, further comprising an insulation material
arranged between the segments.
10. The tool of claim 1, wherein the wear protection shield is made
of high-strength or ultra high-strength steel material.
11. The tool of claim 1, wherein the wear protection shield is
attached on the base body by bonding and/or by a form fit.
12. The tool of claim 1, further comprising a heat conducting paste
placed between the wear protection shield and the base body.
13. The tool of claim 1, wherein the wear protection shield is
comprised of at least two wear protection shield segments disposed
in spaced-apart relation to define a separation gap there
between.
14. The tool of claim 1, wherein the wear protection shield is
comprised of at least two wear protection shield segments of
different thicknesses.
15. The tool of claim 1, wherein the wear protection shield has a
marginal area configured to at least overlap at least one area of
the base body so as to embrace a marginal area of the base
body.
16. The tool of claim 15, wherein the marginal area is folded
over.
17. A deep drawing tool for hot forming and optional press
hardening a steel structure, comprising: an upper tool; a lower
tool in opposition to the upper tool; and a downholder configured
to hold a workpiece to be deep drawn between the upper and lower
tools, each of said upper and lower tools being made in one of two
ways, a first way in which the upper tool and the lower tool have
each a base body which is made of a light metal alloy, and a wear
protection shield arranged on the base body of at least one of the
upper and lower tools, a second way in which the upper tool and the
lower tool have each a base body which is comprised of at least two
segments, and a wear protection shield arranged upon the at least
two segments, wherein at least one of the at least two segments of
the base body of at least one of the upper and lower tools has a
cooling channel, wherein the base body with the one segment having
the cooling channel is made of highly heat conductive material.
18. The deep drawing tool of claim 17, wherein the downholder is
configured for arrangement on opposite sides, said downholder being
configured for movement separately from the upper tool and/or lower
tool so that the workpiece held by the downholder contacts the wear
protection shield of the lower tool or the wear protection shield
of the upper tool as the upper and lower tools are moved in
relation to one another.
19. The deep drawing tool of claim 17, wherein the downholder
includes an upper part and a lower part arranged adjacent to the
upper tool and the lower tool.
20. The deep drawing tool of claim 19, wherein the upper part and
the lower part are movable separately to the upper and lower
tools.
21. A deep drawing tool, comprising: an upper tool and a lower
tool, each having a base body made of a light metal alloy; a
downholder configured to hold a workpiece to be deep drawn between
the upper and lower tools, and a wear protection shield arranged on
the base body of at least one of the upper and lower tools.
22. The deep drawing tool of claim 21, wherein the base body of the
upper and lower tools is comprised of at least two segments, said
wear protection shield being arranged upon the at least two
segments, wherein at least one of the at least two segments of the
base body of at least one of the upper and lower tools has a
cooling channel, wherein the light metal alloy of the base body
with the one segment having the cooling channel being highly heat
conductive.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application claims the priority of German Patent
Application, Serial No. 10 2013 110 299.9, filed Sep. 18, 2013,
pursuant to 35 U.S.C. 119(a)-(d), the disclosure of which is
incorporated herein by reference in its entirety as if fully set
forth herein.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to a tool for hot forming and
press hardening metallic steel structures, and to a deep drawing
tool for hot forming and optional press hardening of metallic steel
structures.
[0003] The following discussion of related art is provided to
assist the reader in understanding the advantages of the invention,
and is not to be construed as an admission that this related art is
prior art to this invention.
[0004] It is generally known to shape a metal sheet, especially of
steel sheet, by a forming process to manufacture a
three-dimensional sheet metal product. Metal sheet products of this
type are used in particular in the automobile industry to
manufacture body components or also to produce motor vehicle
control arms or housing components for example.
[0005] To satisfy the demand for motor vehicles to have little
consumption while still exhibiting a vehicle body of increased
stiffness, high-strength or ultra high-strength steel materials
have been developed. This involves steel alloys that are heated to
temperatures above the AC3 point, formed in hot state to a specific
shape and then rapidly cooled down so as to produce a substantially
martensitic microstructure and to thereby establish high-strength
or also ultra high-strength properties in the steel structure. This
manufacturing process is also known as hot forming and press
hardening.
[0006] Heating of a metal sheet to a pliable forming temperature is
normally implemented in a furnace, in particular a continuous
furnace or also in a temperature-controlled station. The
thus-heated metal sheet is transferred to a thermoforming tool and
formed to a specific shape while being at the pliable forming
temperature. Combined hot forming and press hardening tools are
also constructed to cool down the metal sheet that is formed in hot
state and held between an upper tool and a lower tool of the
thermoforming tool. Cooling is realized in the thermoforming tool
by cooling channels through which a coolant flows to attain the
intended cooling rate.
[0007] Upper and lower tools are normally made of tool steel which
is expensive because of its material properties and difficult to
work with because of its high strength characteristics.
[0008] It would therefore be desirable and advantageous to provide
an improved tool which obviates prior art shortcomings, is easy and
cost-effectively to manufacture and exhibits little tool wear,
while being capable to realize an effective cooling capacity and to
produce distinct regions of different strengths in a structure.
SUMMARY OF THE INVENTION
[0009] According to one aspect of the present invention, a
thermoforming tool for hot forming and press hardening a steel
structure includes an upper tool and a lower tool, each having a
base body made of highly heat conductive material and comprised of
at least two segments, wherein the base body of at least one of the
upper and lower tools has a cooling channel, and a wear protection
shield arranged on the base body of at least one of the upper and
lower tools.
[0010] In accordance with the present invention, a thermoforming
tool is provided which is capable to manufacture motor vehicle
components, such as A pillars, B pillars, C pillars or D pillars or
also transmission tunnels or outer vehicle components such as
engine hood or vehicle door, using a forming process. The upper
tool can normally be lowered in a direction of the lower tool, with
a cavity being defined between the upper and lower tools, when the
thermoforming tool is closed. The cavity is sized to substantially
correspond to the metal sheet thickness of the sheet metal part to
be shaped. The base body of both the upper tool and the lower tool
is made of highly heat conductive material, with both the upper
tool and the lower tool being covered by a wear protection shield.
It is, of course, also conceivable to provide only the upper tool
or only the lower tool with such a wear protection shield.
[0011] According to another advantageous feature of the present
invention, the base body can be made of a light metal alloy, e.g.
of an aluminum alloy, as highly heat conductive material.
[0012] According to another aspect of the present invention, a deep
drawing tool for hot forming and optional press hardening a steel
structure, includes an upper tool, a lower tool in opposition to
the upper tool, and a downholder configured to hold a workpiece to
be deep drawn between the upper and lower tools, each of the upper
and lower tools being made in one of two ways, a first way in which
the upper tool and the lower tool have each a base body which is
made of a light metal alloy, and a wear protection shield arranged
on the base body of at least one of the upper and lower tools, a
second way in which the upper tool and the lower tool have each a
base body which is comprised of at least two segments, and a wear
protection shield arranged upon the at least two segments, wherein
at least one of the at least two segments of the base body of at
least one of the upper and lower tools has a cooling channel,
wherein the base body with the one segment having the cooling
channel is made of highly heat conductive material.
[0013] Thus, the present invention provides a deep drawing tool
that can be used not only for realizing a pure press forming but
also a deep drawing process and can be manufactured in a
cost-effective manner. The base body may initially be made of a
material that can easily be machined, e.g. of a light metal. Placed
on this base body is the wear protection shield which can be made
of a material that has a higher strength than the material of the
base body, e.g. of a tool steel. Advantageously, the wear
protection shield is replaceable. A deep drawing tool can thus be
manufactured in accordance with the present invention that is
cost-effective and requires little maintenance since it is only
required to replace the wear protection shield when worn off.
Advantageously, the wear protection shield is threadably engaged
and/or bonded onto the base body.
[0014] The deep drawing tool can have a base body which is
constructed in segments. At least one of the segments can have one
or more cooling channels, and the base body may be made of highly
heat conductive material. In this way, the workpiece being deep
drawn, especially when press hardened after undergoing hot forming,
can be provided with regions of different strengths. These regions
can be realized by different cooling rates and/or cooling
temperatures in the respective segments.
[0015] According to another advantageous feature of the present
invention, the segments can be arranged in spaced-apart relation to
define a separation gap so that the segments are physically and
thus thermally separated from one another. As a result, the
workpiece can be tailored to have distinct regions with sharp
edges. As a result of the high heat conductivity of the material of
the base body together with the presence of cooling channels
provides high heat dissipation. The cooling channels can
advantageously be formed as throughbores extending through the base
body, advantageously in a straight line. Some cooling channels may
be spaced at a greater distance from the surface of the wear
protection shield and thus have a greater distance to the workpiece
being cooled down. The presence of a cooling throughbore,
especially rectilinear throughbore, enables a reduction in the
manufacturing costs of the tool, especially of the base body as
there is no need to provide a complicated branched channel
system.
[0016] It will be understood that the afore-described properties
are true for the thermoforming tool as well as for the deep drawing
tool. Thus, any reference to a "tool" in the following description
is used here in a generic sense and the principles described in the
following description apply to both a thermoforming tool and a deep
drawing tool.
[0017] In accordance with the present invention, the base body is
made of at least two parts so that the base body is divided in
segments. The segments may be disposed in spaced-apart relationship
to define a separation gap there between which may configured as a
slot and extend in orthogonal relation to the wear protection
shield. Advantageously, an insulation material may be arranged in
the separation gap between the segments. Of course, the separation
gap may also be configured substantially slot-free. In any event,
any heat conduction between the segments should be greatly
decreased or avoided. In this way, it becomes possible to maintain
the segments of the base body at different temperatures in order to
be able to establish different strength properties with sharply
defined transition zones, as the structure or workpiece is cooled.
Transition zones of less than 100 mm, or less than 80 mm, or less
than 50 mm, or even less than 30 mm can be attained.
[0018] As the segments of the base body have cooling channels in
the form of throughbores, the base body can be manufactured of a
light metal alloy by way of a casting process or by a material
removing machining process. Tool costs and manufacturing costs are
relatively low compared to a base body made of tool steel, and the
formation of cooling channels is also easy and cost-effectively to
realize. Machining processes such as drilling or milling methods,
are applicable and there is no need for a complex channel system.
The cooling channels can be made as throughbores from one side of
the base body to extend continuously to the other side since
sufficient heat dissipation is realized in view of the high heat
conducting properties of the base body or respective segment. At
the same time, the presence of the separation gap between two
adjacent segments ensures that each segment reaches its individual
desired temperature, especially with respect to the quenching
behavior during the press hardening process. Cooling channels can
thus be manufactured especially cost-effectively, thereby further
greatly reducing the overall tool manufacturing costs, when
compared to a conventional thermoforming tool made of tool
steel.
[0019] Examples of a coolant include especially fluidic media, e.g.
cooling liquids, such as water. The use of water is possible
because light metal alloys exhibit only slight corrosion
susceptibility. Other examples of coolant include also air or
compressed air or other gaseous media. The cooling rate necessary
for the respective region of the structure can also be influenced
by the size or cross sectional area of the cooling channels and/or
pressure of the coolant and/or flow rate of the coolant through a
respective segment. A tensile force can be adjusted in some areas,
depending on the alloy, between 1,500 and 2,000 MPa, and in some
areas between 750 and 1,050 MPa. Thus, two adjacent segments of the
upper tool and/or the lower tool can be provided with different
cool-down rates to establish different strength properties in the
structure.
[0020] According to another advantageous feature of the present
invention, the wear protection shield can be made of high-strength
or ultra high-strength steel material. Advantageously, the wear
protection shield is attached to the base body of the tool in such
a way that it is simply exchangeable after a certain production
time to maintain dimensional precision of the structures to be
manufactured, without any need to replace the upper tool or lower
tool or the overall thermoforming tool. Advantageously, the wear
protection shield is replaceably or detachably connected to the
base body or segments of the base body. The wear protection shield
may hereby be attached on the base body by bonding and/or by a form
fit, in particular by riveting or bolted connection.
[0021] According to another advantageous feature of the present
invention, a heat conducting paste can be placed between the wear
protection shield and the base body. In this way, an intense heat
transfer is realized by heat conduction and quenching of the
thermoformed structure can be tailored.
[0022] According to another advantageous feature of the present
invention, the wear protection shield can be comprised of at least
two wear protection shield segments disposed in spaced-apart
relation to define a separation gap there between. In this way, the
transition zone in the structure can be provided with even sharper
edges when the structure is quenched differently in various
regions, and it is possible to use the segmented wear protection
shields to suit the respective thickness of the metal sheet that
may have jumps in thickness and thus involves a tailored material
that undergoes shaping and hardening as tailored material in a
correspondingly defined cavity. The separation gap between adjacent
wear protection shield segments may have the shape of a slot or may
be slot-free, and insulating material may also be placed into the
separation gap.
[0023] According to another advantageous feature of the present
invention, the wear protection shield can have a marginal area
configured to at least overlap at least one area of the base body
so as to embrace a marginal area of the base body. The term
"marginal area" relates hereby to a circumferential area or to an
area extending all-around. By embracing the border of the base
body, the wear protection shield is securely fixed by a form fit
upon the base body, especially in horizontal direction. In
particular, when a deep drawing tool is involved, the marginal area
between wear protection shield and base body will not get damaged,
when the metal sheet to be formed is misaligned so that the wear
protection shield is prevented from inadvertently detaching from
the base body in the event the metal sheet is tilted or skewed.
[0024] According to another advantageous feature of the present
invention, a downholder can be provided for arrangement on opposite
sides. The downholder may hereby be arranged on both sides so as to
be placed entirely next to the upper tool or lower tool and may be
configured for movement separately from the upper tool and/or lower
tool. As an alternative, the downholder may also be configured such
as to be arranged on one side only, for example approaching from
the lower tool or from the upper tool and to clamp the metal sheet
to be formed as it contacts the upper tool or the lower tool. The
downholder is also in this case movably constructed independently
from the upper and lower tools.
BRIEF DESCRIPTION OF THE DRAWING
[0025] Other features and advantages of the present invention will
be more readily apparent upon reading the following description of
currently preferred exemplified embodiments of the invention with
reference to the accompanying drawing, in which:
[0026] FIGS. 1a, 1b show a cross section and a longitudinal section
of a first embodiment of a thermoforming tool according to the
present invention;
[0027] FIGS. 2a, 2b show a cross section and a longitudinal section
of a second embodiment of a thermoforming tool according to the
present invention;
[0028] FIGS. 3a, 3b show a cross section and a longitudinal section
of a third thermoforming tool according to the present invention
for shaping tailored blanks;
[0029] FIGS. 4a, 4b show a cross section and a longitudinal section
of a fourth embodiment of a thermoforming tool according to the
present invention, depicting segmented wear protection shields;
[0030] FIGS. 5a, 5b show a cross section and a longitudinal section
of a fifth embodiment of a thermoforming tool according to the
present invention for making tailored blanks;
[0031] FIGS. 6a, 6b show a cross section and a longitudinal section
of a sixth embodiment of a thermoforming tool according to the
present invention, depicting a through opening in the wear
protection shields;
[0032] FIGS. 7a, 7b show a cross section and a longitudinal section
of a seventh embodiment of a thermoforming tool according to the
present invention, depicting the presence of a passively cooled
base body;
[0033] FIGS. 8a, 8b show a cross section and a longitudinal section
of an eight embodiment of a thermoforming tool according to the
present invention, depicting the presence of a passively cooled
base body;
[0034] FIG. 9a shows a cross section of a ninth embodiment of a
thermoforming tool according to the present invention, taken along
the line A-A in
[0035] FIG. 9b and depicting the presence of a passively cooled
base body;
[0036] FIG. 9b shows a longitudinal section of the thermoforming
tool of FIG. 9a;
[0037] FIG. 10 is a plan view of the thermoforming tool of FIGS.
9a, 9b;
[0038] FIGS. 11a, 11b show a cross section and a longitudinal
section of a first embodiment of a deep drawing tool according to
the present invention, depicting a downholder on one side;
[0039] FIGS. 12a, 12b show a cross section and a longitudinal
section of a second embodiment of a deep drawing tool according to
the present invention, depicting a downholder on both sides;
[0040] FIGS. 13a, 13b show a cross section and a longitudinal
section of a third embodiment of a deep drawing tool according to
the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0041] Throughout all the figures, same or corresponding elements
may generally be indicated by same reference numerals. These
depicted embodiments are to be understood as illustrative of the
invention and not as limiting in any way. It should also be
understood that the figures are not necessarily to scale and that
the embodiments are sometimes illustrated by graphic symbols,
phantom lines, diagrammatic representations and fragmentary views.
In certain instances, details which are not necessary for an
understanding of the present invention or which render other
details difficult to perceive may have been omitted.
[0042] Turning now to the drawing, and in particular to FIGS. 1a
and 1b, there are shown a cross section and a longitudinal section
of a first embodiment of a thermoforming tool according to the
present invention, generally designated by reference numeral 1. The
thermoforming tool 1 includes an upper tool 2 and a lower tool 3,
with the upper tool 2 and the lower tool 3 each having a base body
4, 5 made of highly heat conductive material, e.g. light metal
alloy such as aluminum alloy. Currently preferred is a heat
conduction of >130 W/mK. Arranged on the base body 4, 5 of the
upper and lower tools 2, 3 are wear protection shields 6, 7,
respectively. As shown in the cross sectional view of FIG. 1a, both
the lower tool 3 and the upper tool 2 have formed therein a cooling
channel 8 which extends in close proximity to the wear protection
shield 6, 7 through the base body 4, 5.
[0043] As shown in FIG. 1 b by way of the longitudinal section of
the thermoforming tool 1, both the lower tool 3 and the upper tool
2 are each comprised of three segments 9a, 9b, 9c; 10a, 10b, 10c.
Adjacent segments 9a, 9b, 9c; 10a, 10b, 10c are separated by
separation gaps 11, shaped here in the form of slots. Insulating
material may be placed into the separation gaps 11 to prevent heat
conduction between the segments 9a, 9b, 9c; 10a, 10b, 10c. The
cooling channels 8 extend in the non-limiting example shown here
only in the middle segment 9b of the upper tool 2 and the middle
segment 10b of the lower tool 3. As a result, it is primarily the
middle segments 9b; 10b in the upper and lower tools 2, 3,
respectively, that are coolable so as to realize an even heat
dissipation of the upper and lower tools 2, 3 only in the
respective region of the structure (not shown) being shaped.
Adjacent regions in the segments 9a, 9c; 10a, 10c remain unaffected
by the cooling. The wear protection shield 6, 7 is continuous, with
the separation gap 11 between the segments 9a, 9b, 9c; 10a, 10b,
10c inhibiting a respective heat introduction. As a result, a
structure is produced having a distinct transition zone with
sharply defined border.
[0044] FIGS. 2a, 2b show a cross section and a longitudinal section
of a second embodiment of a thermoforming tool according to the
present invention, generally designated by reference numeral 1a.
Parts corresponding with those in FIGS. 1a, 1b are denoted by
identical reference numerals and not explained again. The
description below will center on the differences between the
embodiments. In this embodiment, provision is made for cooling
channels in the form of throughbores 12. As a result, the
throughbores 12 can advantageously be formed in a base body blank
by a material removing drilling process. As an alternative, the
throughbores 12 may also be realized by tubes in the base body 4.
The throughbores 12 thus do no longer extend in close proximity to
the wear protection shield 6, 7. This, however, is insignificant in
view of the high heat conducting capability of the material of the
base body 4 and is more than balanced by the benefit of reduced
manufacturing costs of the structure.
[0045] FIGS. 3a, 3b show a cross section and a longitudinal section
of a third thermoforming tool according to the present invention,
generally designated by reference numeral 1b and useful for forming
tailored blanks. In this embodiment, the wear protection shield 6
on the upper tool 2 and the wear protection shield 7 on the lower
tool 3 are each formed with a thick region 13 and a thin region 14.
As a result, the structure being shaped can be exposed to a greater
surface pressure in the thick region 13, when the thermoforming
tool 1b is closed to thereby ensure high heat dissipation. Air gaps
remain deliberately in the thin region 14 between the structure
being shaped and the wear protection shield 6, 7 so as to establish
here a lesser heat dissipation.
[0046] FIGS. 4a, 4b show a cross section and a longitudinal section
of a fourth embodiment of a thermoforming tool according to the
present invention, generally designated by reference numeral 1c. In
this embodiment, provision is made for a wear protection shield
having wear protection shield segments 6a, 6b, 6c; 7a, 7b, 7c in
correspondence to the subjacent base body 4, 5. Adjacent wear
protection shield segments 6a, 6b, 6c; 7a, 7b, 7c are separated by
a separation gap to inhibit heat conduction between the wear
protection shield segments 6a, 6b, 6c; 7a, 7b, 7c and to receive an
insulating material 17. As an alternative, or in addition to the
cooling channels 8, shown in FIGS. 1a, b, provision may also be
made for heating elements 16, for example in the form of heating
cartridges, in the tool segments 9a, 9c; 10a, 10c to maintain the
temperature in particular regions.
[0047] FIGS. 5a, 5b show a cross section and a longitudinal section
of a fifth embodiment of a thermoforming tool according to the
present invention, generally designated by reference numeral 1d and
useful for making a tailored blank 18. In this embodiment, the wear
protection shield 6 of the upper tool 2 and the wear protection
shield 7 of the upper tool 3 are provided with protrusions 19 so
that the cavity that forms as the thermoforming tool 1d is closed
has a contour that complements the contour of the tailored blank
18. As shown in particular in FIG. 5b, the wear protection shields
6, 7 have varying thicknesses D1, D2, with the thickness D1 being
smaller than the thickness D2.
[0048] FIGS. 6a, 6b show a cross section and a longitudinal section
of a sixth embodiment of a thermoforming tool according to the
present invention, generally designated by reference numeral 1e. In
this embodiment, each of the wear protection shields 6, 7 has an
opening 20 via which, for example, the shaped structure can be
perforated subsequently or in the thermoforming tool 1e. When being
perforated subsequently, the opening 20 causes reduced heat
dissipation, cooling rate and thus strength in this region so that
the perforation can be implemented at relatively slight force, tool
wear and without risk of microcracks.
[0049] FIGS. 7a, 7b show a cross section and a longitudinal section
of a seventh embodiment of a thermoforming tool according to the
present invention, generally designated by reference numeral 1f. In
this embodiment, the segments of the base body 4, 5, are not
directly and actively cooled through provision of cooling channels;
Rather, a bottom plate 21 is attached to the base body 4, 5 and
provided with a plurality of cooling channels 8. Heat is thus
dissipated via the wear protection shields 6, 7 through the base
bodies 4, 5 and the bottom plates 21. In view of the high heat
conduction of the base body 4, 5, a desired heat dissipation is
again rendered possible.
[0050] FIGS. 8a, 8b show a cross section and a longitudinal section
of an eight embodiment of a thermoforming tool according to the
present invention, generally designated by reference numeral 1g. In
this embodiment, provision is made for the individual segments 9a,
9b, 9c; 10a, 10b, 10c of the upper tool 2 and the lower tool 3 to
be formed on bottom plates 21, respectively, with the segments 9a,
9b, 9c; 10a, 10b, 10c having a substantially constant or even
reduced volume ratio for heat dissipation in relation to the bottom
plate 21. Thus, the individual segments 9a, 9b, 9c, 10a, 10b, 10c
are made in accordance with the present invention of highly heat
conductive material to ensure adequate heat dissipation of the wear
protection shield 6, 7. The segments 9a, 9b, 9c; 10a, 10b, 10c can
easily be provided with the desired contour and the thermoforming
tool 1g can be cost-effectively manufactured in combination with
the wear protection shield 6, 7. The presence of the bottom plate
21 also imparts the thermoforming tool 1g with a necessary
stiffness, when applying the forming forces. As can be seen in
particular in FIG. 8b, the middle. segments 9b, 10b are provided
with cooling channels 8 in the form of rectilinear throughbores 12.
As alternative, tubes may be cast into the middle segments 9b; 10b
during production.
[0051] FIGS. 9a, 9b show a cross section and a longitudinal section
of a ninth embodiment of a thermoforming tool according to the
present invention, generally designated by reference numeral 1h. In
this embodiment, provision is made for heating elements 16 in the
tool segments 9a, 9c; 10a, 10c, and both the upper tool 2 and the
lower tool 3 are each provided with a solid bottom plate 21. In
addition, the middle segment 9b is provided with a cooling channel
8 which is fluidly connected to a central cooling channel 22 in the
bottom plate 21 so that coolant can be fed to the bottom plate 21
and flow via the cooling channel 22 to the segments 9b; 10b of the
upper tool 2 and the lower tool 3.
[0052] FIG. 10 is a plan view of the thermoforming tool 1h,
depicting the bottom plate 21 of the upper tool 2 with segments 9a,
9b, 9c. The heat zone and the cold zone are separated from one
another by a respective separation gap 11. Illustration of the wear
protection shield 6 is omitted here for sake of simplicity. The
segments 9a, 9b, 9c may be coupled onto the bottom plate 21 by a
form fit and/or interference fit and/or material joint.
[0053] FIGS. 11a, 11b show a cross section and a longitudinal
section of a first embodiment of a deep drawing tool according to
the present invention, generally designated by reference numeral
23. Parts corresponding with those in FIGS. 1a, 1b are denoted by
identical reference numerals and not explained again. In this
embodiment, provision is made for a downholder 24 or sheet metal
holder which is coupled to the lower tool 3 and movable in relation
thereto. The downholder 24 is constructed to clamp the not shown
workpiece as it contacts the upper tool 2 via the wear protection
shield 6 in opposition to a spring force acting on the downholder
24. Attached to the base body 4 of the upper tool 2 is wear
protection shield 6 and attached to the base body 5 of the lower
tool 3 is wear protection shield 7. Both the upper tool 2 and the
lower tool 3 have formed therein cooling channels in the form of
throughbores 12 so that the formed structure can be quenched after
conclusion of the deep drawing process.
[0054] As shown in particular in FIG. 11 b by way of the
longitudinal section through the deep drawing tool 23, the base
body 4 of the upper tool 2 and the base body 5 of the lower tool 3
are each comprised of the three segments 9a, 9b, 9c; 10a, 10b, 10c.
The segments 9a, 9b, 9c; 10a, 10b, 10c are respectively separated
from one another by separation gaps 11. The segments 9b, 9c of the
upper tool 2 and the segments 10b, 10c of the upper tool 3 have
throughbores 12, whereas the segment 9a of the upper tool 2 and the
segment 10a of the lower tool 3 are devoid of any cooling
channels.
[0055] FIGS. 12a, 12b show a cross section and a longitudinal
section of a second embodiment of a deep drawing tool according to
the present invention, generally designated by reference numeral
23a. As shown in particular in FIG. 12a, a metal sheet 25 to be
formed is clamped by a downholder 24 between an upper downholder
part 24a and a lower downholder part 24b. The downholder 24 is
movable separately in relation to both the upper tool 2 and the
lower tool 3. The wear protection shield 6 of the upper tool 2 and
the wear protection shield 7 of the lower tool 3 are hereby
configured to embrace the base bodies 4, 5 at least in some areas
of their marginal areas. As a result, added lateral securement is
realized with respect to the horizontal direction H, and the metal
sheet 25 is prevented from sliding off in press stroke direction or
vertical direction V via the border-side folded region of the wear
protection shields 6, 7. The wear protection shields 6, 7 thus
embrace the marginal area of the base bodies 4, 5, respectively on
two opposite sides.
[0056] The longitudinal section of FIG. 12b clearly shows that only
the segment 9b, 10b of the upper and lower tools 2, 3 has cooling
channels in the form of throughbores 12, whereas the segments 9a,
9c; 10a, 10c are made of a material that is different than the
material of the segment 9b; 10b. For example, the material of the
segments 9a, 9c; 10a, 10c may have a heat conductivity which is
smaller than the heat conductivity of the material for the segments
9b; 10b. Taking into account the thermal separation as a result of
the separation gap 11 between adjacent segments 9a, 9b, 9c; 10a,
10b, 10c, heat dissipation into the segments 9a, 9c; 10a, 10c is
significantly decreased. The wear protection shields 6, 7 do not
embrace the base bodies 4, 5 according to the longitudinal section
of FIG. 12b, although this is, of course, conceivable within the
scope of the invention so that the marginal area of the base bodies
4, 5 is embraced all-around.
[0057] FIGS. 13a, 13b show a cross section and a longitudinal
section of a third embodiment of a deep drawing tool according to
the present invention, generally designated by reference numeral
23b. Also in this embodiment, provision is made for a downholder 24
which is coupled to the lower tool 3 and movable in relation
thereto. The downholder 24 can hereby clamp the not shown metal
sheet as the upper and lower tools 2, 3 are moved in relation to
one another to bring the metal sheet into contact with the wear
protection shield 6 of the upper tool 2. Wear protection plate 7 is
attached to the base body 5 of the lower tool 7. Both the upper
tool 2 and the lower tool 3 have cooling channels in the form of
throughbores 12 so that the formed structure can be quenched after
conclusion of the deep drawing process.
[0058] The longitudinal section of FIG. 13b through the deep
drawing tool 23b clearly shows that the base body 4 of the upper
tool 2 and the base body 5 of the lower tool 3 are each comprised
of three segments 9a, 9b, 9c; 10a, 10b 10c. Unlike in the
embodiment of FIGS. 11a, 11b, the segments 9a, 9b, 9c; 10a, 10b 10c
are free of gaps. The segments 9a, 9b, 9c of the upper tool 2 and
the segments 10a, 10b, 10c of the lower tool 3 have throughbores 12
for cooling the deep drawing tool 23b and thus the steel component,
not shown.
[0059] While the invention has been illustrated and described in
connection with currently preferred embodiments shown and described
in detail, it is not intended to be limited to the details shown
since various modifications and structural changes may be made
without departing in any way from the spirit and scope of the
present invention. The embodiments were chosen and described in
order to explain the principles of the invention and practical
application to thereby enable a person skilled in the art to best
utilize the invention and various embodiments with various
modifications as are suited to the particular use contemplated.
[0060] What is claimed as new and desired to be protected by
Letters Patent is set forth in the appended claims and includes
equivalents of the elements recited therein:
* * * * *