U.S. patent application number 10/558248 was filed with the patent office on 2007-07-19 for method for the production of a hollow profile provided with a terminal lid, and jack console.
This patent application is currently assigned to DAIMLERCHRYSLER AG. Invention is credited to Juergen Gade, Gerhard Linke.
Application Number | 20070163319 10/558248 |
Document ID | / |
Family ID | 33482255 |
Filed Date | 2007-07-19 |
United States Patent
Application |
20070163319 |
Kind Code |
A1 |
Gade; Juergen ; et
al. |
July 19, 2007 |
Method for the production of a hollow profile provided with a
terminal lid, and jack console
Abstract
The invention relates to a process for producing a hollow
profiled section (7) with bulges (37) which is provided with an
end-side closure cover (7), and to a jack bracket (32) produced by
means of this process. To allow simple production of an expanded
hollow profiled section (6) provided with a closure cover (7) and
to demonstrate a jack bracket (32) produced by this process which
entails only a low level of manufacturing outlay yet nevertheless
ensures a high ability to withstand mechanical stresses, it is
proposed that a cup-like cover (7) be pushed into the hollow
profiled section (6), with the hollow profiled section (6) being
placed into a hydroforming die (1). After the latter has then been
closed, an axial ram (8) is introduced into the cover (7) and into
the end of the hollow profiled section, in such a manner that the
rim side of the cover (7) is radially pressed to the surrounding
hollow profiled section (6). The hollow profiled section (6) is
then widened by means of hydroforming pressure.
Inventors: |
Gade; Juergen; (Buxtehude,
DE) ; Linke; Gerhard; (Gaertringen, 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: |
33482255 |
Appl. No.: |
10/558248 |
Filed: |
April 23, 2004 |
PCT Filed: |
April 23, 2004 |
PCT NO: |
PCT/EP04/04298 |
371 Date: |
December 13, 2006 |
Current U.S.
Class: |
72/56 |
Current CPC
Class: |
B21D 26/049 20130101;
B62D 25/2081 20130101; B60S 11/00 20130101; B21D 53/88 20130101;
B21D 39/04 20130101 |
Class at
Publication: |
072/056 |
International
Class: |
B21D 26/02 20060101
B21D026/02; B21J 5/04 20060101 B21J005/04 |
Foreign Application Data
Date |
Code |
Application Number |
May 28, 2003 |
DE |
103 24 276.7 |
Claims
1-13. (canceled)
14. A process for producing a hollow profiled section with bulges
that is provided with an end-side closure cover, in which process a
cup-like cover is pushed into the hollow profiled section,
comprising: placing the hollow profiled section into a hydroforming
die, closing the die, introducing an axial ram into the cover and
into an end of the hollow profiled section, in such a manner that
an edge side of the cover is radially pressed to the surrounding
hollow profiled section, and widening the hollow profiled section
by hydroforming pressure.
15. The process as claimed in claim 14, wherein the cover is fitted
loosely into the hollow profiled section outside the forming
die.
16. The process as claimed in claim 14, wherein the cover is fed to
the hollow profiled section, which has been placed in the forming
die, by the axial ram, and wherein pressing is effected as this
feeding operation takes place.
17. The process as claimed in claim 14, wherein, before being
inserted, the cover has an external diameter which is larger than
an internal diameter of the hollow profiled section.
18. The process as claimed in claim 14, wherein a rim of the cover
is clamped in place by the hollow profiled section with
hydroforming pressure combined, at the same time, with axial
advancing of the axial ram, and wherein hollow profiled section
material is displaced into a space delimited by a closure edge of
the cover rim and an opposite shoulder of the axial ram by an
advancing operation in combination with the hydroforming
pressure.
19. The process as claimed in claim 14, wherein an opening is
formed in the cover base, and wherein the hollow profiled section
is widened by pressurized fluid introduced into the interior of the
hollow profiled section via a passage of the axial ram and the
opening in the cover base.
20. The process as claimed in claim 19, wherein an extension in the
shape of a bottleneck is formed around the opening in the cover
base at the cover, and wherein a molded projection in the form of a
hollow journal on an end side of the axial ram is introduced into
the extension.
21. The process as claimed in claim 14, wherein, after widening the
hollow profiled section, closure edges of the hollow profiled
section and of a cover rim are acted on by a slide integrated
guidably within the forming die and engaging in an axial running
groove of the axial ram opening toward an end side of the axial
ram.
22. The process as claimed in claim 14, wherein closure edges of a
rim of the cover are shaped so as to protrude radially outward.
23. The process as claimed in claim 14, wherein a rim of the cover
is perforated, and wherein, after the cover has been pressed to the
hollow profiled section, hollow profiled section material is
pressed into a hole which has been formed in the cover rim by a ram
that is integrated guidably in the die.
24. The process as claimed in claim 14, wherein the hollow profiled
section and the cover, when the axial ram is being introduced, are
pressed onto a section of a cavity of the die which widens
conically toward the axial ram so as to form surfaces of matching
contour on a rim of the cover and on the hollow profiled
section.
25. A jack bracket of the motor vehicle formed using a hollow
profiled section produced as defined by claim 14 and comprising
flanges which are arranged on an end of the hollow profiled section
which is remote from the cover fixing the bracket to a sill of the
motor vehicle in a lower region thereof.
26. The jack bracket as claimed in claim 25, wherein the bracket,
on a cover base, has an opening which forms a receiving element for
a stopper to which a jack can be attached.
27. The process as claimed in claim 16, wherein before being
inserted, the cover has an external diameter which is larger than
an internal diameter of the hollow profiled section.
28. The process as claimed in claim 15, wherein a rim of the cover
is clamped in place by the hollow profiled section with
hydroforming pressure combined, at the same time, with axial
advancing of the axial ram, and wherein hollow profiled section
material is displaced into a space delimited by a closure edge of
the cover rim and an opposite shoulder of the axial ram by an
advancing operation in combination with the hydroforming
pressure.
29. The process as claimed in claim 16, wherein a rim of the cover
is clamped in place by the hollow profiled section with
hydroforming pressure combined, at the same time, with axial
advancing of the axial ram, and wherein hollow profiled section
material is displaced into a space delimited by a closure edge of
the cover rim and an opposite shoulder of the axial ram by an
advancing operation in combination with the hydroforming
pressure.
30. The process as claimed in claim 17, wherein a rim of the cover
is clamped in place by the hollow profiled section with
hydroforming pressure combined, at the same time, with axial
advancing of the axial ram, and wherein hollow profiled section
material is displaced into a space delimited by a closure edge of
the cover rim and an opposite shoulder of the axial ram by an
advancing operation in combination with the hydroforming
pressure.
31. The process as claimed in claim 15, wherein an opening is
formed in the cover base, and wherein the hollow profiled section
is widened by pressurized fluid introduced into the interior of the
hollow profiled section via a passage of the axial ram and the
opening in the cover base.
32. The process as claimed in claim 16, wherein an opening is
formed in the cover base, and wherein the hollow profiled section
is widened by pressurized fluid introduced into the interior of the
hollow profiled section via a passage of the axial ram and the
opening in the cover base.
33. The process as claimed in claim 17, wherein an opening is
formed in the cover base, and wherein the hollow profiled section
is widened by pressurized fluid introduced into the interior of the
hollow profiled section via a passage of the axial ram and the
opening in the cover base.
Description
BACKGROUND AND SUMMARY OF THE INVENTION
[0001] This invention relates to a process for producing a hollow
profiled section provided with a closure cover on the end side, and
to a jack bracket.
[0002] The prior art, which is described by German document DE 100
49 048 C1, discloses a process for producing ends for hollow
shafts. In this process, a plastic stopper is pushed into the
hollow shaft. The hollow shaft together with plastic stopper is
placed in a hydroforming die, after which an axial ram then acts on
the end of the hollow shaft in which the plastic stopper is
located. At the same time, a hydroforming pressure is generated in
the hollow shaft, the effect of which, in combination with the
axially acting pressure of the ram, is to press the wall of the
hollow shaft onto both end sides of the plastic stopper. This
captively fixes the plastic stopper in the hollow shaft, since it
is held in a frictionally and positively locking manner by this
compression.
[0003] Furthermore, German document DE 195 28 309 C2 discloses a
jack bracket which has been formed from a sheet-metal shell
structure. The jack bracket has attachment regions by which it is
secured to a lower sill region by means of spot-welding. The welded
shell structure has an opening at its other end, into which a
plastic stopper that has an indentation is fitted; a journal of a
jack can be inserted into this indentation. The shell structure of
the bracket is relatively complex to produce in terms of process
engineering and apparatus, since it comprises a number of
parts.
[0004] This invention is based on the object of providing a process
which makes it easy to produce an expanded hollow profiled section
provided with a closure cover. Moreover, it is intended to
demonstrate a jack bracket which requires only a low level of
manufacturing outlay yet nevertheless ensures a high ability to
withstand mechanical stresses.
[0005] According to the invention, this object is achieved by the
claimed process, and by the claimed jack bracket.
[0006] By use of a single-piece, circumferentially continuous
hollow profiled section as the base body for the jack bracket, a
high flexural strength of the bracket is achieved, which is able to
withstand even very high mechanical stresses without suffering
damage. The hollow profiled section can be ideally matched to the
periphery of the bracket by means of the hydroforming, which
manifests itself in bulges which are simple to form using the
hydroforming process, on account of the relatively low degrees of
deformation. As a result of the absence of manufacturing tolerances
from the process, it is readily possible to automate the attachment
of the bracket to the lower region of the motor vehicle sill. This
attachment merely requires the formation of weld flanges, which can
be made by relatively simple cutting and bending operations at the
corresponding end of the hollow profiled section. The opposite end
of the hollow profiled section is closed off by a closure cover, to
which the jack can be directly or indirectly fitted. The pressing
of the closure cover within the hydroforming die, which forms the
basis of the process according to the invention for joining the
closure cover and the hollow profiled section, eliminates the need
for additional tools, such as holding means and pressing tools,
which would otherwise be required for external pressing of the
cover within the hollow profiled section. Moreover, the pressing is
effected by the introduction of the axial ram into the hollow
profiled section, which is economical in terms of process
engineering since it is in any case an operation which is
imperative for the seal to be produced during the hydroforming
process. On account of the hollow profiled section bearing without
play between the cavity of the hydroforming die and the cover rim,
which for its part bears closely against the pressure-exerting
slope of the inner axial ram, the hollow profiled section maintains
its contours, without undesirable creases and dents, in the
pressing region. Then, the bulges are formed by introducing a
hydroforming pressure into the interior of the hollow profiled
section. If the cover completely closes off the hollow profiled
section, the hydroforming pressure is introduced via the other end
of the hollow profiled section. Overall, the apparatus requirements
of the hydroforming process allow this process to be combined with
the pressing process in a single die, which significantly
simplifies the production of an expanded hollow profiled section
with closure cover. The abovementioned need for strong sealing of
the axial ram with respect to the highly pressurized fluid within
the interior of the hollow profiled section produces a high
frictional lock between the cover rim and the hollow profiled
section, which is responsible for extremely good retaining of the
cover on the hollow profiled section for any intended use.
[0007] In a refinement of the process according to the invention,
the cover is fitted loosely into the hollow profiled section
outside the forming die. This has the advantage that closure cover
and hollow profiled section can be preassembled in advance and then
placed in the hydroforming die as a single unit for further
processing.
[0008] In a further advantageous refinement of the invention, which
should be regarded as an alternative to the refinement just
described, the closure cover is fed to the hollow profiled section,
which has been placed in the forming die, by means of the axial
ram, and pressing is effected as this feeding operation takes
place. In this case, economically in terms of process engineering,
the feeding of the closure cover is carried out in a single
operation together with the pressing. Furthermore, the closure
cover is centered on the axial ram even before it is introduced
into the hollow profiled section, and is therefore arranged in the
desired way.
[0009] In a further expedient refinement of the invention, before
inserting the closure cover into the hollow profiled section, the
cover is designed with an external diameter which is larger than
the internal diameter of the hollow profiled section. On account of
the specific design of the two diameters, introduction of the cover
into the hollow profiled section results in a particularly high
level of press fit if the axial ram additionally also has a
pressure-exerting contour. In the other case, the press fit is less
strong, but it is possible to make do without a special
configuration of the pressure-exerting contour of the axial ram.
However, for the diameters indicated, an insertion slope on the
cover rim is useful, to make it easier for the closure cover to be
introduced into the hollow profiled section.
[0010] In a further advantageous configuration of the invention,
the cover rim is clamped in place by the hollow profiled section by
means of hydroforming pressure combined, at the same time, with
axial advancing of the axial ram. Hollow profiled section material
is displaced into a space delimited by a closure edge of the cover
rim and an opposite shoulder of the axial ram by means of the
advancing operation in combination with the hydroforming pressure.
The hydroforming pressure in combination with the pressure-exerting
force of the axial ram on the one hand produces an inwardly
protruding thickened section on the hollow profiled section, which
bears against the cover rim; on the other side, the hollow profiled
section material which flows into the space on account of the
hydroforming pressure and the advancing operation engages behind
the cover rim. This produces a positive lock between hollow
profiled section and closure cover, which boosts the retaining
force between the two components still further.
[0011] In a further expedient configuration of the invention, an
opening in the cover base and a widening of the hollow profiled
section are formed by a pressurized fluid which is introduced into
the interior of the hollow profiled section via a passage in the
axial ram and the opening in the cover base. Forming the opening in
the cover base and providing a fluid passage in the axial ram
provides the latter with an extremely useful multiple function,
namely that of sealing off the supply of pressurized fluid and
pressing the rim of the cover onto the hollow profiled section. The
opening at the cover base can subsequently, after the forming of
the hollow profiled section, serve as a receiving element for a
further component.
[0012] In another refinement, an extension in the shape of a
bottleneck is formed around the opening in the cover base at the
cover, into which extension a molded projection in the form of a
hollow journal on the end side of the axial ram is introduced. If
the cover formed in this manner has already been fitted into the
hollow profiled section, the bottleneck-shaped extension serves as
a centering means for the axial ram, which can then be docked to
the closure cover without jamming, and with its journal-like molded
projection on the end side projecting through the opening in the
cover base. This additionally retains the axial ram on the cover
and--via the latter--on the hollow profiled section. If the closure
cover is not yet retained loosely on the hollow profiled section,
but rather is only to be supplied together with the axial ram, the
cover can easily be fitted together with the axial ram, so that the
closure cover is held captively on the axial ram as it is fed to
and introduced into the hollow profiled section.
[0013] In a further expedient refinement of the invention, after
the widening of the hollow profiled section has taken place, the
closure edges of the hollow profiled section and of the cover rim
are acted on by means of a slide, which is integrated guidably
within the forming die and engages in an axial running groove of
the axial ram, which is open toward the end side of the axial ram.
The slide in this case prevents the closure cover from being
released from its press-fit to the hollow profiled section and also
being pulled outward after the axial ram has been pulled out. The
movement of pulling out the axial ram remains unaffected by the
slide, on account of the open groove.
[0014] In a further advantageous configuration of the invention,
the closure edges of the cover rim are shaped so as to protrude
radially outward. The annular collar which is then formed creates
an axial stop for the closure cover, which axial stop is supported
against the closure edge of the hollow profiled section, so that in
the event of axially higher mechanical loads on the pressed
assembly of hollow profiled section and closure cover, which are
exerted from the cover side of the hollow profiled section, the
cover cannot be pressed into the interior of the hollow profiled
section.
[0015] According to a further advantageous configuration of the
invention, the cover rim is perforated, and after the cover has
been pressed to the hollow profiled section, hollow profiled
section material is pressed into the hole which has in each case
been formed in the cover rim by means of a ram that is integrated
guidably in the forming die. This produces a local positively
locking connection between the hollow profiled section and the
cover, which on the one hand prevents the closure cover from being
entrained in the same direction when the axial ram is being pulled
off and on the other hand also prevents the closure cover from
being pressed into the interior of the hollow profiled section on
account of higher mechanical axial loads from both axial
directions.
[0016] In a further expedient development of the process according
to the invention, the hollow profiled section and the cover, when
the axial ram is being introduced, are pressed onto a section of
the cavity of the forming die which widens conically toward the
axial ram, so as to form surfaces of matching contour on the cover
rim and on the hollow profiled section. In this refinement, the
pressed assembly of hollow profiled section and closure cover is
strengthened still further. Furthermore, the closure cover is also
prevented from being pressed into the interior of the hollow
profiled section.
[0017] Finally, in an expedient further configuration of the jack
bracket according to the invention, the bracket, on the cover base,
has an opening which forms a receiving element for a stopper to
which a jack can be attached. On account of the accurate
positioning of the closure cover within the hollow profiled
section, which for its part has been produced without manufacturing
tolerances on account of the use of the hydroforming process, the
opening for receiving the stopper is very accurately defined. This
enables a lifting platform designed as a jack, which is completely
automatically controlled, always to be fitted to the correct
position on the jack bracket when the motor vehicle is in the
workshop.
[0018] In the text which follows, the invention is explained in
more detail on the basis of a number of exemplary embodiments
illustrated in the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 shows, for a process according to the invention, an
arrangement of a hydroforming die, a hollow profiled section, a
closure cover and an axial ram in the form of a longitudinal
section through a partial exploded view,
[0020] FIG. 2 shows a longitudinal section, for the process
according to the invention, through a closure cover with
bottleneck-shaped extension and an axial ram with a journal-like
molded projection, in an exploded view,
[0021] FIG. 3 shows the arrangement of FIG. 1 in the position in
which closure cover and hollow profiled section are being pressed
together with the axial ram introduced,
[0022] FIG. 4 shows a longitudinal section, for the process
according to the invention, through a hollow profiled section and a
closure cover with closure edges shaped so as to protrude radially
outward, in the form of an exploded illustration,
[0023] FIG. 5a shows, for a process according to the invention, a
longitudinal section through part of an arrangement of a
hydroforming die, a hollow profiled section, a closure cover and an
axial ram in the pressing position of the axial ram, with the
hollow profiled section engaging behind the closure cover at the
rim side,
[0024] FIG. 5b shows an enlarged excerpt from the location of the
closure cover which is being engaged behind in FIG. 5a,
[0025] FIG. 6 shows, for a process according to the invention, an
arrangement of hollow profiled section, closure cover and a
hydroforming die as well as an axial ram in the pressing position
of the axial ram with a slide acting on the closure edges of hollow
profiled section and closure cover,
[0026] FIG. 7a shows, for a process according to the invention, an
arrangement of hydroforming die, hollow profiled section, axial ram
and closure cover with a ram which displaces hollow profiled
section material into a hole in the closure cover,
[0027] FIG. 7b shows an enlarged excerpt from the pressed assembly
of hollow profiled section and closure covers shown in FIG. 7a at
the location at which hollow profiled section material is being
displaced into the hole in the closure cover,
[0028] FIG. 8 shows, for a process according to the invention, a
longitudinal section through an arrangement of a hydroforming die,
an axial ram, a hollow profiled section and a closure cover in the
pressing position with a section of the cavity of the forming die
which widens conically toward the axial ram,
[0029] FIG. 9 shows a jack bracket according to the invention in
the form of a side view of an exploded illustration, and
[0030] FIG. 10 shows the jacket bracket from FIG. 9 in the form of
a perspective view after the pressing of hollow profiled section
and closure cover.
DETAILED DESCRIPTION OF THE INVENTION
[0031] FIG. 1 illustrates an open hydroforming die 1 comprising a
top die part 2 and a bottom die part 3, which with an inner cavity
4 define a hydroforming space 5. A hollow profiled section 6, which
may be formed from a light metal or steel and may be in the form of
a blank made from a drawn tube or a plate which has been rolled up
and then welded with a longitudinal seam, has already been placed
into the lower die part 3. The arrangement shown, comprising the
forming die 1 and the hollow profiled section 6, also comprises a
closure cover 7 and an axial ram 8, which are in this case separate
from one another outside the forming die 1, in order to explain the
production process according to the invention, but are in each case
arranged aligned with the hollow profiled section 6 in order to
stipulate the direction in which they are pushed together. The
closure cover 7 is of cup-shaped design; its base 9 rests on the
side facing the hollow profiled section 6. The cover 7 may be a
deep-drawn sheet-metal part or a casting, in particular a
hot-chamber die casting. The axial ram 8 narrows toward its end
side 10 facing the closure cover 7 by way of a shoulder 11, from
where it merges, via spherically rounded pressure-exerting flanks
12, into the planar end side 10. The rounding of the flanks 12 is
intended to prevent the closure cover 7 from being damaged by sharp
edges which would otherwise be present during introduction of the
axial ram 8 into the closure cover 7 or during pressing to the
hollow profiled section. The height of the shoulder 11 is such that
it is of the same size as the wall thicknesses of the hollow
profiled section 6 and of the closure cover 7 together. If the
closure cover 7 has already been inserted loosely into the hollow
profiled section 6 in advance, with the result that the hollow
profiled section 6 together with the closure cover 7 is placed into
the forming die 1 as an assembly to be pressed, the diameter of the
axial ram 8 in the region of its pressure-exerting flanks 12 is
greater than the internal diameter of the closure cover 7. The
profile of the rim 13 of the closure cover 7 substantially matches
the spherical contour of the axial ram 8 in the region of its
pressure-exerting flanks 12. This produces uniform pressing of
hollow profiled section 6 and closure cover 7, thereby optimizing
the retaining of the closure cover 7 on the hollow profiled section
6. However, if the closure cover 7 is pushed onto the axial ram 8
in order for them to be jointly introduced into the forming die 1,
the internal diameter of the closure cover rim 13 is of course
larger than the diameter of the axial ram 8 in the region of its
pressure-exerting flanks 12. To achieve appropriate pressing to the
hollow profiled section 6, the closure cover rim 13, at its
external diameter in this region, is overdimensioned all the way
around with respect to the internal diameter of the hollow profiled
section 6. The axial ram 8 has a centrally running passage 14 which
opens out at the end side 10. The closure cover 7 has a central
opening 15 in its base 9.
[0032] To carry out the process, the hollow profiled section 6 is
placed into the forming die 1, which is then closed. As has been
mentioned, the closure cover 7 may previously have been fitted
loosely into the hollow profiled section 6 or the closure cover 7
may have been pushed onto the axial ram 8. In the later case, the
opening in the closure cover 7 is aligned with the point where the
passage 14 of the axial ram 8 opens out. Then, the axial ram 8
together with the closure cover 7 is introduced into the end of the
hollow profiled section, with the result that the closure cover 7
is pressed to the hollow profiled section end, on account of its
dimensions and the pressure-exerting flanks 12 of the axial ram 8.
The pressed assembly produced in this way as illustrated in FIG. 3
is then placed under hydroforming pressure by a pressurized fluid
being introduced into the hollow profiled section interior 16 via
the passage 14 in the axial ram and the central opening 15 in the
closure cover 7 and pressurized by means of a pressure-generating
system which is connected to the rear side of the passage 14. As a
result of the hydroforming pressure generated, the hollow profiled
section 6 is widened until it comes to bear against the cavity 4 of
the forming die 1, so as to form bulges 37 (cf. FIGS. 5-10). The
molding space 5 within the die 1 is now completely filled. It is in
principle conceivable for a closure cover 7 to be introduced,
successively or simultaneously, into both ends of the hollow
profiled section 6.
[0033] FIG. 2 shows a variant of the axial ram 8 and the closure
cover 7. In this case, the end side 10 of the axial ram 8 has a
journal-like molded projection 17, through which the passage 14
passes. Accordingly, with matching contours, the closure cover 7
has a bottleneck-shaped extension 18, in which the molded
projection 17 of the axial ram 8 can be fitted. This provides
particularly good retaining of the closure cover 7 on the axial ram
8. As can be seen from FIG. 4, in a further structural variant of
the closure cover 7, the closure edges 19 of the cover rim 13 can
be shaped so as to protrude radially inward, producing a lip-like
annular collar.
[0034] In a variant of the invention, as shown in FIGS. 5a and b,
in the pressed-assembly position, the axial ram 8 is advanced even
further, so that sufficient hollow profiled section material can be
supplied to the region of the bulge 37 to be produced, thereby
ensuring that the hollow profiled section 6 is widened in a
reliable process. During the advancing of the axial ram 8, with
hydroforming pressure P.sub.i accordingly acting on all sides as
indicated by the arrows, on the one hand a thickened formation 20
is formed on the hollow profiled section 6 immediately adjoining
the pressed region, and on the other hand hollow profiled section
material, at the continuing end of the profiled section, is
displaced into a space 21 delimited by the closure edge 19 of the
closure cover rim 13 and the opposite shoulder 11 of the axial ram
8. The thickened portion 20 pressing the cover rim 13 inward and
the hook-like closure 22 of the hollow profiled section end causes
the closure rim 13 to be clamped in a positively locking manner
toward its end, resulting in particularly good retaining of the
closure cover 7 on the hollow profiled section 6 as a result of the
axial fixing achieved. After the desired expanding 37 of the hollow
profiled section 6 and of the pressed assembly of hollow profiled
section 6 and closure cover 7 has ended, the hydroforming pressure
is relieved and the axial ram 8 is withdrawn from the hydroforming
die 1, after which the forming die 1 is opened and the finished
assembly comprising hollow profiled section 6 and closure cover 7
is removed.
[0035] In a further variant of the invention, FIG. 6 reveals a
slide 23, which is integrated guidably in the forming die 1 within
a guide bore 24 which runs radially with respect to the cavity 4.
To prevent the closure cover 7 from being released from the pressed
assembly with the hollow profiled section 6 during retraction of
the axial ram 6 after the widening of the hollow profiled section 6
on account of particularly high friction by being pulled along with
it, the slide 23 engages in an axially running groove 25 in the
axial ram 8, which is open toward the end of the hollow profiled
section. In this position, the closure edges 19 and 26 of the cover
rim 13, on the one hand, and of the hollow profiled section 6, on
the other hand, are supported against the side wall 27 of the slide
23 which faces them. The use of a plurality of radially movable
slides 23 arranged offset with respect to one another in the
circumferential direction improves the support and ensures that the
pressed assembly is retained even more firmly.
[0036] A further variant of the invention is illustrated in FIGS.
7a and 7b. After the bulge 37 has been formed, in the region of the
pressing, hollow profiled section material is pressed into
corresponding holes 30 in the cover rim 13 by means of a plurality
of rams 29 which are integrated guidably in the forming die 1 in
corresponding guide bores 28 running radially with respect to the
cavity 4 of the forming die 1, these holes being produced on the
closure cover 7 during or shortly after its production.
[0037] In a further variant of the invention as shown in FIG. 8,
the cavity 4, adjoining the molding space 5, is widened conically
with a shallow opening angle toward the axial ram 8. The hollow
profiled section 6 and the closure cover 7 are pressed onto this
conically widened section of the cavity 4 during insertion of the
axial ram 8, with surfaces with contours corresponding to the part
31 of the cavity 4 being formed at the cover rim 13 and at the
hollow profiled section 6.
[0038] FIG. 9 illustrates a jack bracket 32 which has been produced
using the process according to the invention. For the sake of
clarity, in the illustration the closure cover 7 with its
bottleneck-shaped extension 18 is illustrated separately from the
hollow profiled section 6. The hollow profiled section 6 also has a
plurality of flanges 34 at its end 33 remote from cover 7, which
flanges 34 are partially turned over and serve on the one hand as a
stop and on the other hand as joining surfaces for a lower region
of a sill of the motor vehicle. To attach the bracket 32 to the
sill and any other peripheral body regions of the motor vehicle,
for example by means of spot-welding, passages 36 are formed in a
side wall 35 of the bracket 32, via which passages lateral access
into the hollow profiled section 6 to the adjoining inner walls is
possible in a simple way. It is conceivable, in a manner which is
economical in terms of process engineering, for these passages 36
to be produced by perforating during the hydroforming operation
which expands the hollow profiled section 6.
[0039] FIG. 10, as a modification to FIG. 9, shows the pressed
assembly of the hollow profiled section 6 and the closure cover 7,
with the closure edge 26 of the hollow profiled section 6
projecting beyond the closure edge 19 of the rim 13 of the closure
cover 7. It should also be pointed out once again at this point
that the opening 15 at the cover base 9 serves as a receiving
element for a stopper to which a jack can be fitted. Furthermore,
the process according to the invention is not restricted only to
the production of jack brackets. In addition to the brackets, the
process can be used for all components which are to be hydroformed
with closure covers that are intended to at least partially close
off one or more holes at the component, such as structural elements
of a motor vehicle, in particular including closure nodes in a
frame structure.
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