U.S. patent application number 10/582476 was filed with the patent office on 2007-11-29 for punch for producing holes in the wall of hollow parts subjected to the action of internal high pressure.
This patent application is currently assigned to DaimlerChrysler AG. Invention is credited to Stephan Kuschel, Frank Schmuck, Jens Schult.
Application Number | 20070271979 10/582476 |
Document ID | / |
Family ID | 34672720 |
Filed Date | 2007-11-29 |
United States Patent
Application |
20070271979 |
Kind Code |
A1 |
Kuschel; Stephan ; et
al. |
November 29, 2007 |
Punch For Producing Holes In The Wall Of Hollow Parts Subjected To
The Action Of Internal High Pressure
Abstract
A punch designed for producing holes in the walls of hollow
parts, the part being subjected to the action of high pressure in
the interior by a medium during the punching. In particular when
producing hollow parts by the internal high pressure forming
process, it is normal practice, following the forming and with the
part still located in the forming tool, to make holes in the wall.
In order to avoid a drop in the internal high pressure when cutting
through the wall of the part, the punch is designed so as to taper
at an angle toward the cutting edge in its region plunging into the
part to be punched. As a result, sealing of the hole occurs during
the punching.
Inventors: |
Kuschel; Stephan; (Hamburg,
DE) ; Schmuck; Frank; (Hamburg, DE) ; Schult;
Jens; (Stelle-Ashausen, 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: |
34672720 |
Appl. No.: |
10/582476 |
Filed: |
November 17, 2004 |
PCT Filed: |
November 17, 2004 |
PCT NO: |
PCT/EP04/13014 |
371 Date: |
July 11, 2007 |
Current U.S.
Class: |
72/55 |
Current CPC
Class: |
B21D 28/28 20130101;
B21D 28/34 20130101; B21D 26/035 20130101 |
Class at
Publication: |
072/055 |
International
Class: |
B21D 28/28 20060101
B21D028/28 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 13, 2003 |
DE |
103 58 500.1 |
Claims
1-3. (canceled)
4. A punch for producing holes in the wall of hollow parts
subjected to the action of internal high pressure and accommodated
in the mold of an internal high pressure forming tool, wherein the
punch is designed to be pushed from the mold wall into the mold
interior space, said punch comprising: a first portion; and a
tapered portion having a cutting edge, wherein said tapered portion
extends from said first portion to said cutting edge at an angle
whereby, when said punch plunges into a part to be punch, a sealing
surface between said part and said punch is formed.
5. The punch as claimed in claim 4, wherein the punch, in its
initial position, is arranged in the mold in such a way that the
cutting edge is set back relative to an inner wall of the mold.
6. The punch as claimed in claim 4, wherein the angle of taper is
greater than 0.degree. and is at most 30.degree..
7. The punch as claimed in claim 5, wherein the angle of taper is
greater than 0.degree. and is at most 30.degree..
8. The punch as claimed in claim 6 wherein the angle of taper at
least 1.degree. and at most 3.degree..
9. The punch as claimed in claim 4, wherein the tapered portion is
conically constructed whereby material in the region of walls of
the punched hole is upset.
Description
BACKGROUND AND SUMMARY OF THE INVENTION
[0001] The invention relates to the design of punches for producing
holes in the walls of hollow parts, the part being subjected to the
action of high pressure in the interior by a medium during the
punching.
[0002] In particular when producing hollow parts by the internal
high pressure forming process, it is normal practice, following the
forming and with the part still located in the forming tool, to
make holes in the wall.
[0003] German Patent Document DE 43 22 063 C2 discloses a method
and a device for cutting out a blank from a wall of a hollow body
produced according to the internal high pressure forming process.
In this case, the blank is cut out directly after the internal high
pressure forming by means of a punch acting from outside on the
lateral surface of the hollow body. To this end, the driven punch
passes through the internal high pressure forming tool. A tool of
the generic type is described in German Patent Document DE 199 34
663 A1.
[0004] When cutting through the hollow body, a pressure drop in the
hollow body inevitably occurs due to the resulting leakage. If a
plurality of holes are to be made in the hollow body, the holes
must be made exactly simultaneously so that the internal pressure
required for satisfactory punching is available during all the
punching operations. This simultaneity of the punch drives requires
considerable control input and very high pumping capacities or
correspondingly large accumulators. Also disadvantageous is the
extremely abrupt loading of the hydraulic components.
[0005] The object of the invention is to design the punches for use
of the generic type in such a way that a drop in the internal high
pressure when cutting through the wall of the part is largely
avoided.
[0006] The punch is designed so as to taper at an angle in the
direction of the cutting edge in its region plunging into the part
to be punched. As a result, during the cutting, the material in the
region of the hole wall is upset in accordance with the tapered
outer contour of the punch, and the hole is immediately sealed by
the punch. In this way, when making a plurality of holes, the
punches can be moved slowly and asynchronously to one another with
respect to time. The quality of the holes produced and the process
reliability increase considerably as a result. The cost in terms of
equipment can be kept correspondingly low, since the tools can be
of simpler and more compact design. Thus no expensive measures are
required for achieving synchronized sequences, such as tool bridges
or electronic path control.
[0007] An exemplary embodiment of the invention is shown in the
drawing and described in more detail below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 shows a diagrammatic illustration of a punch before
the punching,
[0009] FIG. 2 shows a diagrammatic illustration of a punch after
the punching.
DETAILED DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 shows, in a partial section, a hollow part 2 which is
preferably produced by the internal high pressure forming process
and is still subjected to the action of internal high pressure and
which bears with its outer contour against the inner wall of an
internal high pressure forming tool 4. In the internal high
pressure forming tool 4, a punch 1 is arranged in such a way as to
be movable in the arrow direction preferably by means of a
hydraulic drive (not shown). In its region plunging into the part
2, the punch 1 is designed to taper conically toward the cutting
edge 3. The angle of taper is in this case greater than 0.degree.
and is at most 30.degree., but preferably 1.degree. to 3.degree..
In this case, the cutting edge 3 of the punch 1 is set back
slightly relative to the mold inner wall of the internal high
pressure forming tool 4.
[0011] To make the hole, the punch 1 is moved in the direction of
the part 2, and the cutting edge 3 cuts through the wall of the
part in the process. The conically designed region of the punch 1
upsets the material in the region of the hole wall 5 and the hole
is simultaneously sealed by the punch 1. Therefore no drop in the
internal high pressure occurs (FIG. 2).
[0012] Since the internal high pressure is maintained in this way,
it is possible, without any problems, to make further holes
asynchronously with respect to time using a plurality of
punches.
* * * * *