U.S. patent application number 10/582474 was filed with the patent office on 2007-12-06 for internal high-pressure shaping device.
This patent application is currently assigned to DAIMLERCHRYSLER AG. Invention is credited to Matthias Schroeder, Stefan Schwarz.
Application Number | 20070277574 10/582474 |
Document ID | / |
Family ID | 34672718 |
Filed Date | 2007-12-06 |
United States Patent
Application |
20070277574 |
Kind Code |
A1 |
Schroeder; Matthias ; et
al. |
December 6, 2007 |
Internal High-Pressure Shaping Device
Abstract
The invention relates to a device (10) for the internal high
pressure forming of a hollow profile (5), comprising a forming tool
and a sealing arrangement for holding and sealing an end (12) of
the hollow profile (5), this end (12) projecting from the
impression (16) of the forming tool, the sealing arrangement (11)
having a section (6), plunging into the hollow profile (5), of an
axial punch (4) and at least one clamping jaw (3) which, when the
section (6) of the axial punch (4) has plunged in, presses radially
from outside on the hollow profile end (12) in such a way that the
clamping jaw (3) fixes the latter in position. It is essential to
the invention in this case that an actuator (14) is provided which
drives the clamping jaw (3) for displacing it only radially to the
hollow profile axis.
Inventors: |
Schroeder; Matthias;
(Gruenendeich, DE) ; Schwarz; Stefan; (Luenen,
DE) |
Correspondence
Address: |
CROWELL & MORING LLP;INTELLECTUAL PROPERTY GROUP
P.O. BOX 14300
WASHINGTON
DC
20044-4300
US
|
Assignee: |
DAIMLERCHRYSLER AG
Epplestrasse 225
Stuttgart
DE
70567
|
Family ID: |
34672718 |
Appl. No.: |
10/582474 |
Filed: |
November 17, 2004 |
PCT Filed: |
November 17, 2004 |
PCT NO: |
PCT/EP04/13015 |
371 Date: |
May 15, 2007 |
Current U.S.
Class: |
72/61 |
Current CPC
Class: |
B21D 26/045
20130101 |
Class at
Publication: |
072/061 |
International
Class: |
B21D 26/02 20060101
B21D026/02 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 13, 2003 |
DE |
103 58 493.5 |
Claims
1-10. (canceled)
11. A device for internal high pressure forming of a hollow
profile, comprising: a forming tool, a sealing arrangement for
holding and sealing an end of the hollow profile, this end
projecting from an impression of the forming tool, the sealing
arrangement having a section of an axial punch, adapted to plunge
into the hollow profile, and at least one clamping jaw which, when
the section of the axial punch has plunged in, presses radially
from outside on the end of the hollow profile in such a way that
the clamping jaw fixes the latter in position, and an actuator
which drives the clamping jaw for displacing it only radially to an
axis of the hollow profile, wherein at least one V-ring is arranged
on a side of the clamping jaw facing the end of the hollow
profile.
12. The device as claimed in claim 11, wherein the actuator is
formed by or includes at least one hydraulic cylinder.
13. The device as claimed in claim 11, wherein the actuator is
formed by at least one electric motor.
14. The device as claimed in claim 11, wherein the forming tool is
formed from at least two die parts displaceable relative to one
another.
15. The device as claimed in claim 11, wherein the clamping jaw is
mounted on the forming tool in such a way as to be radially
displaceable relative to the axis of the hollow profile.
16. The device as claimed in claim 11, wherein the actuator enables
the clamping jaw to be displaced when the forming tool is open.
17. The device as claimed in claim 14, wherein the forming tool is
designed in such a way that the die parts can be displaced while
the clamping jaw fixes the end of the hollow profile.
18. The device as claimed in claim 11, wherein the clamping jaw is
supported on the forming tool, and wherein the forming tool is
supported on a foundation.
19. The device as claimed in claim 11, wherein the clamping jaw and
the forming tool are each supported on a foundation.
20. The device as claimed in claim 11, wherein the clamping jaws
can be carried along axially.
21. The device as claimed in claim 12, wherein the actuator is
formed by at least one electric motor.
22. The device as claimed in claim 12, wherein the forming tool is
formed from at least two die parts displaceable relative to one
another.
23. The device as claimed in claim 13, wherein the forming tool is
formed from at least two die parts displaceable relative to one
another.
24. The device as claimed in claim 12, wherein the clamping jaw is
mounted on the forming tool in such a way as to be radially
displaceable relative to the axis of the hollow profile.
25. The device as claimed in claim 13, wherein the clamping jaw is
mounted on the forming tool in such a way as to be radially
displaceable relative to the axis of the hollow profile.
26. The device as claimed in claim 14, wherein the clamping jaw is
mounted on the forming tool in such a way as to be radially
displaceable relative to the axis of the hollow profile.
27. The device as claimed in claim 12, wherein the actuator enables
the clamping jaw to be displaced when the forming tool is open.
28. The device as claimed in claim 13, wherein the actuator enables
the clamping jaw to be displaced when the forming tool is open.
29. The device as claimed in claim 14, wherein the actuator enables
the clamping jaw to be displaced when the forming tool is open.
30. The device as claimed in claim 15, wherein the actuator enables
the clamping jaw to be displaced when the forming tool is open.
Description
BACKGROUND AND SUMMARY OF THE INVENTION
[0001] The present invention relates to a device for internal high
pressure forming.
[0002] A method and a device for the internal high pressure forming
of a hollow profile closed at the periphery form the subject matter
of a German Patent Application, still not published at the time of
the present application, having the official reference 103 49 699.8
and dated Oct. 24, 2003. The known device has an internal high
pressure forming tool with a sealing arrangement which contains an
axial punch having a section plunging into the hollow profile for
holding and sealing an end of the hollow profile, this end
projecting from the impression of the forming tool. Furthermore, a
unit for generating a high fluid pressure is provided for expanding
the hollow profile by means of fluidic internal high pressure.
Owing to the fact that an outside diameter of the axial punch on
the plunging section is equal to or falls slightly below the inside
diameter of the hollow profile end, and owing to the fact that the
sealing arrangement contains at least one clamping jaw and a
pressing element which, when the section of the axial punch has
plunged in, presses radially on the hollow profile end, the
clamping jaw fixes the hollow profile end in position. These
measures prevent the hollow profile blank from being able to be
pulled off the axial punch during the internal high pressure
forming process and thus prevent its sealing effect from being
reduced or even completely neutralized. Since the hollow profile
blank, on account of the firm, axially immovable hold at the end,
cannot be drawn into the impression during the forming, firstly the
original overall length of the hollow profile blank is unaffected
by the forming and secondly no material of the hollow profile end
can subsequently flow from the end into the mold space. In the case
of long forming sections, a largely uniform distribution of the
wall thickness can be achieved at each point of the hollow profile
blank.
[0003] European document EP 1 152 843 B1 discloses a device for the
internal high pressure forming of a hollow profile, which device
has a forming tool and a sealing arrangement for holding and
sealing an end of the hollow profile, this end projecting from the
impression of the forming tool. The sealing arrangement is formed
by a section of an axial punch, this section plunging into the
hollow profile, and by at least one clamping jaw which, when the
section of the axial punch has plunged in, presses radially from
outside on the hollow profile end in such a way that the clamping
jaw fixes the latter in position. The clamping jaw is connected to
an actuator which drives it for displacing it only radially to the
hollow profile axis.
[0004] German document DE 197 51 407 C1 discloses a device for
hydraulically sealing a hollow profile. The device has a die and a
clamping and feed unit and also a plurality of sealing elements
closing the hollow profile. In the region of the sealing location,
the die consisting of two die halves has, on the inside, a
respective rounded bulged section extending radially inward over
the periphery, the clamping and feed unit being provided with an
axially movable mandrel which can be pushed into the hollow profile
by means of a push-pull element. This mandrel is positioned with
respect to the die in such a way that the bulged sections of the
die lie such that they correspond to a mandrel section of
corresponding design. Since the distance from the tube end is
therefore not limited, sealing at any desired location in the tool
is possible.
[0005] German document DE 38 20 952 C2 discloses a device for
hydraulically expanding metallic hollow profiles generally open at
end faces. The open end faces in this case are closed by rigid
sealing heads which surround the inner or outer surface of the
hollow profile in a close-fitting manner but at a slight distance
apart. A sealing gap in between is sealed off in an elastic sealing
ring which is designed as a hollow body and to which internal
pressure can be applied. In addition, the sealing ring is enclosed
in the sealing head in such a way that, as a result of the internal
pressure, it can expand only in the direction of the outer or inner
surface of the hollow profile to be sealed and comes into tight
contact with the latter. The result of the enclosing of the sealing
ring is therefore that the elastic material cannot give way
laterally. Since, furthermore, the hydraulic expansion pressure is
also applied in the sealing gap, provision is made for the internal
pressure in the sealing ring to always be kept so far above this
expansion pressure that the contact pressure of the sealing ring on
the surface of the hollow profile is always above the expansion
pressure and thus reliable sealing is ensured.
[0006] German document DE 197 33 473 A1 discloses a method and a
device for connecting a hollow-cylindrical air/fuel-ratio detector
holder to an exhaust pipe provided with an opening for admitting
exhaust gas to the air/fuel-ratio detector fastened in the holder.
In this case, the method uses the internal high pressure technique
for connecting the air/fuel-ratio detector holder.
[0007] By means of internal high pressure, the contour of the
exhaust pipe is adapted in a simple manner to the bearing contour
of the lateral surface of the holder at the location at which the
future bearing surface of the holder is provided. The connection of
the lateral surface of the holder to the exhaust pipe saves
construction space. The holder, at this location, is virtually sunk
into the exhaust pipe, but at least into the pipe wall.
[0008] The present invention deals with the problem of specifying
an improved embodiment for a device for internal high pressure
forming of the type mentioned at the beginning, which embodiment
ensures in particular reliable holding and sealing of the
semi-finished ends of the hollow profile and at the same time
enables high-quality components formed by internal high pressure to
be produced.
[0009] This problem is solved according to the invention, with
advantageous embodiments forming the subject matter of the
dependent claims.
[0010] According to the invention, in a device for the internal
high pressure forming of a hollow profile, which device has a
sealing arrangement for holding and sealing an end of the hollow
profile, this end projecting from an impression of the forming
tool, an actuator drives a clamping jaw for displacing it only
radially to the hollow profile axis and thus presses the clamping
jaw from outside onto the hollow profile end in such a way that the
latter is fixed in position. In this way, improved sealing and
holding of the hollow profile end can be achieved. Counteracting
the pressure force in the process is a section of an axial punch,
this section plunging into the hollow profile and being part of the
sealing arrangement and supporting the hollow profile end from
inside against the clamping jaw pressing from outside.
[0011] The actuator results in the hollow profile end already being
clamped and thus held and sealed before the actual forming
operation, so that the hollow profile blank can be moved into the
forming tool when the latter is open and as a result any damage to
a surface of the hollow profile blank can be avoided or at least
reduced. At the same time, the hollow profile blank can be reliably
held during the entire production process by being pressed against
the axial punch by means of the clamping jaw acting radially from
outside. As a result, this prevents a situation in which the hollow
profile blank can be pulled off the axial punch during the internal
high pressure forming process and thus its sealing effect is
reduced or even neutralized.
[0012] Since the hollow profile blank cannot be drawn into the
impression or cavity block, firstly the original overall length of
the hollow profile blank remains unaffected by the forming and
secondly no material of the hollow profile blank can subsequently
flow from the end into the mold space, so that, in the case of long
forming sections, a largely uniform distribution of the wall
thickness prevails at each point of the hollow profile blank.
[0013] The largely uniform distribution of the wall thickness also
ensures production of a component coil without any problems, from
which, after forming has been effected, a plurality of individual
components of identical configuration are produced in a subsequent
parting process, these individual components having identical or at
least similar functional properties on account of the uniform
distribution of the wall thickness.
[0014] Since, due to the device according to the invention, the
hollow profile end is not changed in its shape by expansion, and at
least the inside diameter is also retained, subsequent end trimming
may be dispensed with, which saves production time and reduces the
costs for the entire production process.
[0015] According to the invention, at least one V-ring is arranged
on a side of the clamping jaw facing the hollow profile end. Due to
the interlocking thereby achieved, not only is the hollow profile
end held more intensely between the clamping jaw and the axial
punch, but the axial material flow within the hollow profile end is
interrupted, which prevents creeping of the hollow profile at its
end in the direction of the forming tool impression. The result of
this is that lower pressure forces have to be applied in order to
sufficiently counter the drawing-in which is caused during the
internal high pressure forming.
[0016] According to a preferred configuration of the invention, the
actuator comprises at least one hydraulic cylinder or is formed by
at least one hydraulic cylinder. As a result, the clamping jaw can
be pressed onto the hollow profile end hydraulically and thus in a
powerful and precise manner. At the same time, hydraulic cylinders
constitute a drive technology which has proved successful for many
years and is thus reliable, so that the actuator can be realized in
a cost-effective manner with regard to operation and
maintenance.
[0017] According to an advantageous embodiment of the invention,
the actuator enables the clamping jaw to be displaced when the
forming tool is open. The forming tool may be formed, for example,
from at least two die parts which are displaceable relative to one
another and form the impression in the closed state. Due to the
displaceability of the clamping jaw when the forming tool is open,
it is possible to move the hollow profile blank into the forming
tool without there being a risk of damage to the surface of the
hollow profile blank in the process, since the two die parts lie
well outside the path of movement of the hollow profile blank.
Especially high quality requirements can be fulfilled by surface
damage being avoided or reduced.
[0018] The die parts can expediently be displaced while the
clamping jaw fixes the hollow profile end. This results in a method
advantage, since the die parts must first be displaced onto the
hollow profile blank directly before the internal high pressure
forming and thus premature damage to the surface of the hollow
profile blank caused by a bearing surface of the cavity block can
be avoided. At the same time, this prevents the end of the hollow
profile blank from being drawn in as a result of preprofiling for
the case where the hollow profile blank, from the closing movement
of the forming tool, is to be compressed and thus preprofiled.
[0019] Further important features and advantages of the invention
are apparent from the claims, from the drawings, and from
associated description of the drawing figures.
[0020] It goes without saying that the abovementioned features and
the features still to be explained below can be used not only in
the respectively specified combination but also in other
combinations or on their own without departing from the scope of
the present invention.
[0021] Preferred exemplary embodiments of the invention are shown
in the drawings and are described in more detail below, the same
designations designating identical or functionally identical or
similar components.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 shows one part of a device for internal high pressure
forming in an initial position,
[0023] FIG. 2 shows an illustration similar to that of FIG. 1 but
with an axial punch placed against one end of a hollow profile,
[0024] FIG. 3 shows an illustration similar to that of FIG. 2 but
with a clamping jaw pressed onto the end of the hollow profile from
outside, and
[0025] FIG. 4 shows an illustration similar to that of FIG. 3 but
with closed forming tool.
DETAILED DESCRIPTION OF THE INVENTION
[0026] According to FIG. 1, a device 10 for the internal high
pressure forming of a hollow profile 5 has a cavity block 1,
adjustably mounted clamping jaw 3 arranged thereon, and an axial
punch 4. In this case, the cavity block 1 is part of a forming tool
(not explained in any more detail) in which the hollow profile 5 is
expanded by internal high pressure and is formed in accordance with
an impression 16. The clamping jaw 3 and the axial punch 4 are part
of a sealing arrangement 11 which serves to hold and seal an end 12
of the hollow profile 5, this end 12 projecting from the impression
16 or cavity block 1 of the forming tool. At an end facing the
hollow profile end 12, the axial punch 4 has a plunging section 6
(sealing region), with which the axial punch 4 plunges into the
hollow profile 5.
[0027] In general, according to FIGS. 1 to 4, in each case only one
part of the device, for example a top part in FIGS. 1 and 3 and a
bottom part in FIGS. 2 and 4, is shown.
[0028] The axial punch 4 widens from its plunging section 6 to the
rest of the punch body in a stepped manner while forming a shoulder
(not designated in any more detail), by means of which the axial
punch 4 strikes the hollow profile end 12 while assuming the
position of use. The plunging section 6 of the axial punch 4 is in
this case dimensioned in such a way that it comes to lie in the
position of use (cf. FIGS. 2 to 4) on a certain extension length in
the forming tool. Due to the mounting thus achieved, the axial
punch 4 remains oriented in a centered manner, which helps to
achieve a lasting sealing function.
[0029] Running in the axial punch 4 is at least one axial
action-medium passage 7, which on the one hand is connected to a
unit for generating high fluid pressure and on the other hand opens
out at an end face 13 of the axial punch 4. An outside diameter of
the axial punch 4 on the plunging section 6 is favorably
dimensioned in such a way that it corresponds to the inside
diameter of the hollow profile end 12 or falls slightly below the
latter, so that the section 6 comes to lie in the hollow profile
end 12 free of play, but without plastic expansion of the hollow
profile end 12, or with slight play.
[0030] According to FIG. 1, the sealing arrangement 11 has at least
one clamping jaw 3, which is an integral part of the forming tool
and which is mounted on the outer side of the forming tool in such
a way as to be displaceable radially to the hollow profile axis. At
least one V-ring 2 is provided on an end face, facing the hollow
profile end 12, of the clamping jaw 3, and this V-ring 2, when the
clamping jaw 3 presses on the hollow profile end 12 resting in
place on the plunging section 6, notches and fixes said hollow
profile end 12. The notch produced by the V-ring 2 can be
advantageously used, for example, during further use of the hollow
profile 5 in an operation for joining it to other components.
[0031] According to the invention, an actuator 14 is provided for
actuating the clamping jaw 3 (cf FIGS. 3 and 4) and drives the
latter for displacing it only radially relative to the hollow
profile axis. In this case, the actuator 14 may be formed by at
least one hydraulic cylinder or may comprise at least one hydraulic
cylinder. Alternatively, it is also conceivable for the actuator 14
to be formed by at least one electric motor or to comprise at least
one electric motor.
[0032] In general, the device 2 has at least two die parts 15
adjustable relative to one another, for example a top die part 15'
and a bottom die part 15'', which can be displaced toward and away
from one another independently of the clamping jaw 3. According to
FIGS. 1 to 3, it is shown that the actuator 14 enables the clamping
jaw 3 to be displaced when the forming tool is open.
[0033] In order to enable the clamping jaw 3 to be displaced
independently of the die part 15, the clamping jaw 3, according to
FIG. 3, can be supported for example on the forming tool, that is
to say on the die part 15', whereas the die part 15' is supported
on a foundation 9.
[0034] However, it is also conceivable, according to FIG. 4, for
both the clamping jaw 3 and the die part 15' of the forming tool to
be supported independently of one another on the foundation 9.
[0035] In principle, it is conceivable for the clamping jaws 3 to
be carried along axially. This ensures controllable subsequent
feeding of material during the forming process, as a result of
which the quality of the hollow profile 5 produced can be
increased. In the process, the clamping jaws 3 may either be
carried along passively or via a, for example power-controlled,
actuator (not shown), which permits a displacement of the clamping
jaws 3 with respect to the die parts 15 axially relative to the
hollow profile 5.
[0036] The method sequence during the clamping or internal high
pressure forming process is to be explained briefly below:
[0037] At the start of the method, the hollow profile 5 is inserted
into the bottom die 15'' of the forming tool, whereupon the section
6 of the axial punch 4, according to FIG. 1, is pushed in the
direction of movement 8 into both ends, here into the end 12 of the
hollow profile 5, until its shoulder strikes the hollow profile end
12. Alternatively, it is conceivable for the plunging section 6 to
be pushed into the hollow profile 5 beforehand and for the latter
to then be displaced between the two die parts 15' and 15''.
[0038] After that, in a second method step according to FIG. 2, the
clamping jaw 3 is pressed radially from outside onto the hollow
profile end 12 by means of the actuator 14 and thus fixes the
latter in position on the plunging section 6 of the axial punch 4.
Due to the movement of the clamping jaw 3 in the direction of
movement 8' toward the hollow profile end 12, the latter is notched
by the V-ring 2 due to the pressure force exerted by the actuator
14. In general, it is conceivable for the actuator 14 for
displacing the die parts 15' and 15'' or the clamping jaws 3 to be
designed as a hydraulic or electromechanical actuator.
[0039] The embodiment of the V-ring 2 shown according to FIGS. 1 to
4 represents only one possible variant, clamping jaws 3 without
V-rings 2 also being conceivable. In this case, the clamping jaw 3
is connected frictionally to the hollow profile end 12, with an
interference fit being formed, and is thus sealed.
[0040] According to FIG. 3, the clamping operation and thus the
sealing operation by the clamping jaw 3 being pressed radially onto
the hollow profile end 12 has been completed and the hollow profile
5 is fixed in position in the device 10. The die part 15' is now
displaced toward the hollow profile 5 in the direction of movement
8'' by the actuator 14'. It is conceivable here for either only the
top die part 15' or else the top and the bottom die parts 15', 15''
to perform a closing movement. The two die parts 15' and 15'' are
displaced toward one another until the two die parts 15' , 15''
outside the impression 16 come to lie on the hollow profile 5. In
the process, the die parts 15' and 15'' are displaced, while the
clamping jaw 3 fixes the hollow profile end 12. The clamping effect
of the clamping jaws 3 prevents the hollow profile end 12 from
being drawn into the impression 16 by the top die part 15' during
the closing movement.
[0041] According to FIG. 4, the closing operation of the forming
tool has now been completed, so that the hollow profile 5, by means
of the unit for generating high fluid pressure, can be filled with
a pressure fluid via the at least one action-medium passage 7.
After that, the pressure fluid is put under an internal high
pressure, as a result of which the hollow profile 5 expands and
comes into contact with the inner wall of the impression 16 in such
a way as to conform to the contour. During the expansion, the
clamping jaws 3 prevent the hollow profile end 12 from being drawn
into the impression 16 and at the same time seal the hollow profile
end 12. After the internal high pressure forming has been effected,
first the die parts 15' and 15'' and then the clamping jaws 3 are
retracted or opened, so that the finish-formed hollow profile 5 can
be removed by withdrawal of the axial punch 4.
* * * * *