U.S. patent application number 10/563330 was filed with the patent office on 2006-10-19 for tube bend.
This patent application is currently assigned to Daimlerchrysler AG. Invention is credited to Kai-Uwe Dudziak, Ralf Punjer.
Application Number | 20060230801 10/563330 |
Document ID | / |
Family ID | 33521253 |
Filed Date | 2006-10-19 |
United States Patent
Application |
20060230801 |
Kind Code |
A1 |
Dudziak; Kai-Uwe ; et
al. |
October 19, 2006 |
Tube bend
Abstract
A tube bend has at least one bend zone and two outlet zones
adjoining the latter on both sides. The tube bend has a different
cross-sectional shape from the outlet zones with an identical flow
cross section. The degree of expansion, as the ratio of the
diameter of the component in the bending plane to the diameter of
the blank in the bending plane, has a value between 1 and 1.1.
Inventors: |
Dudziak; Kai-Uwe; (Stelle,
DE) ; Punjer; Ralf; (Seevetal, 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: |
33521253 |
Appl. No.: |
10/563330 |
Filed: |
June 25, 2004 |
PCT Filed: |
June 25, 2004 |
PCT NO: |
PCT/EP04/06883 |
371 Date: |
April 13, 2006 |
Current U.S.
Class: |
72/58 |
Current CPC
Class: |
B21D 26/037 20130101;
F16L 43/00 20130101 |
Class at
Publication: |
072/058 |
International
Class: |
B21D 39/20 20060101
B21D039/20 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 2, 2003 |
DE |
103 29 719.7 |
Claims
1-7. (canceled)
8. A tube piece comprising at least one bend zone, and two outlet
zones adjoining the at least one bend zone on both sides, each of
the outlet zones having an end side for application of pushing rams
of an internal high-pressure tool including a die with a recess
forming a production cross section, wherein the bend zone has a
different cross-sectional shape from the outlet zones with an
approximately identical flow cross section, wherein an axis of
symmetry of the bend zone extends in a bending plane, wherein, in a
region of the bending plane, a degree of expansion, as a ratio of a
diameter of the blank in the bending plane to a diameter of the
component in the bending plane, is between 0.9 and 1, and wherein a
degree of expansion in a region normal to the bending plane is
between 0.3 and 1.
9. A tube piece as claimed in claim 8, wherein multiple bend zones
and multiple bending planes are provided.
10. The tube piece as claimed in claim 8, wherein a transition of
the cross-sectional shape from each outlet zone to the bend zone
extends continuously.
11. The tube piece as claimed in claim 8, wherein the
cross-sectional shape of at least one of the bend zone and the
outlet zones is of round, oval, rectangular or polygonal
design.
12. The tube piece as claimed in claim 8, wherein the degree of
expansion is between 0.6 and 0.8.
13. The tube piece as claimed in claim 9, wherein a transition of
the cross-sectional shape from each outlet zone to the bend zone
extends continuously.
14. The tube piece as claimed in claim 9, wherein the
cross-sectional shape of at least one of the bend zone and the
outlet zones is of round, oval, rectangular or polygonal
design.
15. The tube piece as claimed in claim 10, wherein the
cross-sectional shape of at least one of the bend zone and the
outlet zones is of round, oval, rectangular or polygonal
design.
16. An internal high-pressure tool for manufacturing a tube piece
comprising a die with a recess forming a production cross section
of a tube bend, the recess having at least one bend zone and two
outlet zones adjoining the at least one bend zone on both sides,
wherein the recess of the die has a different cross-sectional shape
from the outlet zones with an identical cross-sectional area
forming the production cross section, wherein an axis of symmetry
of the bend zone extends in a bending plane, wherein, in a region
of the bending plane, a degree of expansion, as a ratio of a
diameter of the blank in the bending plane to a diameter of the
component in the bending plane, is between 0.9 and 1, and wherein a
degree of expansion in a region normal to the bending plane is
between 0.3 and 1.
17. The tool as claimed in claim 16, wherein multiple bend zones
and multiple bending planes are provided.
18. The tool as claimed in claim 16, wherein a transition of the
cross-sectional shape from each outlet zone to the bend zone
extends continuously.
19. The tool as claimed in claim 16, wherein the cross-sectional
shape of at least one of the bend zone and the outlet zones is of
round, oval, rectangular or polygonal design.
20. The tool as claimed in claim 16, wherein the degree of
expansion is between 0.6 and 0.8.
21. The tool as claimed in claim 17, wherein a transition of the
cross-sectional shape from each outlet zone to the bend zone
extends continuously.
22. The tool as claimed in claim 17, wherein the cross-sectional
shape of at least one of the bend zone and the outlet zones is of
round, oval, rectangular or polygonal design.
23. The tool as claimed in claim 18, wherein the cross-sectional
shape of at least one of the bend zone and the outlet zones is of
round, oval, rectangular or polygonal design.
24. A method for manufacturing a tube piece comprising placing a
tube piece blank with a diameter A into a recess of a die of an
internal high-pressure tool so as to be acted on by pushing rams,
forming the tube piece blank to a desired diameter B in outlet zone
regions, forming the tube piece blank to a desired diameter C in a
direction parallel to a bending plane in the region of a bend zone,
forming the tube piece blank to a desired diameter D in the
direction at right angles to the bending plane in the region of the
bend zone, and setting a degree of expansion as the ratio of the
tube piece blank diameter A to the desired tube piece blank
diameter C between 0.9 and 1.
25. The method as claimed in claim 24, wherein the degree of
expansion as a ratio of A to D is set between 0.3 and 1.
26. The method as claimed in claim 25, wherein the degree of
expansion is set between 0.6 and 0.8.
Description
[0001] The present invention relates to a tube piece designed as a
tube bend, with at least one bend zone and two outlet zones
adjoining the latter on both sides with in each case an end side
for the application of pushing rams of an internal high-pressure
tool which comprises a die with a recess forming the production
cross section.
[0002] A method for manufacturing a tube bend is already known from
German document DE 43 22 711 C2. There, the tube section is bent
before internal high-pressure forming and upset axially during the
internal high-pressure forming. In the process, the tube section
undergoes enlargement of the average diameter, this expansion
taking place over the entire periphery relative to the central
axis. Starting from a round tube cross section and taking the
ovality of the cross section in the region of the tube bend brought
about during bending into account, the requisite degree of
expansion is greater in this region of the tube section in relation
to the average degree of expansion.
[0003] The invention has as an object the object of designing and
arranging a tube bend in such a way that stable cross-sectional
enlargement is guaranteed during internal high-pressure
forming.
[0004] According to this invention, the object is achieved by
virtue of the fact that the bend zone has a different
cross-sectional shape from the outlet zones with an approximately
identical flow cross section. The result of this is that the
different cross-sectional shape guarantees loading of the tube bend
and at the same time a throttling effect of the bend zone is
prevented owing to the constant flow cross section.
[0005] The axial pushing force exerted on the tube bend during
manufacture of this internal high-pressure formed part serves, by
virtue of the changed cross-sectional shape in the bend zone, to
support the material flow, the changed cross-sectional shape
preventing a buckling movement of the tube bend.
[0006] It is advantageous if the internal high-pressure tool for
manufacturing a tube piece comprises a die with a recess forming
the production cross section of the tube bend, the recess having at
least one bend zone and two outlet zones adjoining the latter on
both sides. In this connection, the recess of the die has a
different cross-sectional shape from the outlet zones with an
identical cross-sectional area which forms the production cross
section. The recess thus formed, or the internal high-pressure tool
thus formed, guarantees that the tube bend to be formed is acted on
with the requisite axial force without a buckling movement of the
tube bend, in particular in the region of the bending plane or of
the bend plane, taking place. The minimal degree of forming of the
tube bend in the bending plane or bend plane guarantees that the
tube bend bears against the recess of the die in the region of the
bend zone, so that the pushing movement of the pushing rams does
not give rise to a buckling movement, in particular of the tube
bend inner side. In the case of internal high-pressure forming as
known in the prior art, the inner side of the bend zone, that is
the side with the smaller bending radius, would be upset owing to
the pressure action alone as the shaped geometry provides for a
smaller radius of curvature than the blank. Superimposing the axial
pushing movement of the pushing rams necessary in places on this
material upsetting leads to failure of the material wall. This is
prevented by the tube bend which bears against the die in the bend
zone, the bend being pressed against the die wall on account of the
pressure action without upsetting forming having been carried out
beforehand.
[0007] An additional possibility is that an axis of symmetry of the
bend zone extends in a bending plane and, in the region of the
bending plane, the degree of expansion, as the ratio of the
diameter of the component in the bending plane to the diameter of
the blank, in the bending plane, is between 1 and 1.1. The blank is
consequently formed only slightly.
[0008] It is furthermore advantageous if the degree of expansion in
the region normal to the bending plane is between 1 and 2, in
particular between 1.3 and 1.5. In this connection, it is
advantageous if the degree of forming increases proportionally
starting from the bending plane and reaches its maximum value
toward the normal.
[0009] For this, it is also advantageous if a number of bend zones
and a number of bending planes are provided. In the manufacture of
more complex tube bend shapes, a number of bend zones can be
provided, each bend zone having its own bending plane. The changing
cross-sectional shaping is then adapted according to the course of
the bending planes, which guarantees the bearing according to the
invention of each bend zone in the region of the respective bending
plane.
[0010] According to a preferred embodiment of the solution
according to the invention, provision is lastly made that a
transition of the cross-sectional shape from each outlet zone to
the bend zone extends continuously. The continuous cross-sectional
adaptation between the cross-sectional shape of the outlet zones
and the cross-sectional shape of the bend zone guarantees minimal
flow loss of the media flowing in the tube bend.
[0011] It is of particular importance for the present invention
that the cross-sectional shape of the bend zone and/or of the
outlet zones is of round, oval, rectangular or polygonal
design.
[0012] In connection with the design and arrangement according to
the invention, it is advantageous if a tube piece blank with a
diameter A is placed into the recess of the die of the internal
high-pressure tool and is acted on by the pushing rams. The tube
piece blank is formed or expanded to a desired diameter B in the
region of the outlet zones, the tube piece blank being formed or
expanded to a desired diameter C in the direction parallel to the
bending plane in the region of the bend zone, and the tube piece
blank being formed to a desired diameter D in the direction at
right angles to the bending plane in the region of the bend zone.
The degree of expansion as the ratio of C to A is set between 1 and
1.1. Depending on material and material thickness, a greater degree
of expansion, that is greater forming, is possible within the
bending plane in the region of the critical bend zone without a
buckling movement occurring. In this connection, the workpiece can
already bear against the die with the inner wall part, that is with
the wall part with the smallest bending radius, in the region of
the critical bend zone before the process. The minimal forming is
generated in the bending plane, in particular in the wall region
with the largest bending radius, that is the outer wall region. The
critical buckling movement in the inner wall region is consequently
prevented. Larger forming operations with a degree of forming
appreciably greater than 1.1 (with regard to the ratio of deformed
size to blank size) cannot, however, be realized within the bending
plane. In the dimensioning of the degree of expansion, the elastic
yield point of the material is also to be taken into account, so
that in particular the ratio of C to A can rise above 1.1 and the
bearing of the elastically expanded bend zone against the die is
nevertheless guaranteed.
[0013] It is furthermore advantageous if the degree of expansion as
the ratio of D to A is set between 1 and 2, in particular between
1.3 and 1.5. In this connection, a degree of forming of 2, that is
a twofold enlargement of the internal high-pressure formed part
starting from the blank size, represents for the usual materials a
maximum value which, depending on cross-sectional shape change,
must be reached to guarantee a constant flow cross section.
[0014] Further advantages and details of the invention are defined
by the patent claims, explained in the description, and illustrated
in the figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 shows a longitudinal sectional illustration of a tube
piece blank in the die;
[0016] FIG. 1b is a view along the cross section C-C;
[0017] FIG. 2 is a longitudinal sectional illustration of an
expanded tube piece in the die, and
[0018] FIG. 2b is a view along the cross section D-D.
DETAILED DESCRIPTION OF THE INVENTION
[0019] A tube bend blank 1 designed as a tube piece blank and
illustrated in FIG. 1 has an axis of symmetry 1.6 and a diameter A
which is constant along the axis of symmetry 1.6. In this
connection, the tube bend blank 1 is bent by 90.degree. starting
from a cylindrical basic shape and has an axis of symmetry 1.6
which is correspondingly curved by 90.degree.. The radius of
curvature of the axis of symmetry 1.6 is approximately 1.5 times
the diameter A.
[0020] The tube bend blank 1 thus formed has a bend zone 1.1 in the
region of the curvature and a first cylindrical outlet zone 1.2 and
a second cylindrical outlet zone 1.3. At the end of the two outlet
zones 1.2, 1.3, the tube bend blank 1 comprises a first end side
1.2' and a second end side 1.3', to which pushing rams 2, 3 of an
internal high-pressure forming device are connected, which on the
one hand serve for axial pressure action and on the other hand
introduce the pressure medium. The tube bend blank 1 is arranged
within a die 4 which comprises a recess 4.5 for receiving the tube
bend blank 1. The tube bend blank 1 is coupled to the pushing rams
2, 3 at its two end sides 1.2', 1.3'. In addition to the recess
4.5, the die 4 comprises a further recess 6 which adjoins the
recess 4.5 radially and, according to FIG. 2, guarantees a special
shaping geometry of the tube bend blank 1.
[0021] In the region of the bend zone 4.1, the recess 4.5 has in
the bending plane or bend plane the same diameter A as the tube
bend blank 1. According to the cross-sectional illustration C-C,
the recess 4.5 of the die 4 has an appreciably larger diameter D
(according to section D-D) in the direction perpendicular to the
bending plane or bend plane.
[0022] In the region of the two outlet zones 4.2, 4.3, the recess
4.5 of the die has, differing from the bend zone 4.1, a cylindrical
basic shape (not illustrated further) corresponding to the tube
bend blank 1. In the region of the two outlet zones 4.2, 4.3, the
recess 4.5 has a larger diameter B (according to FIG. 2) than the
tube bend blank 1. Consequently, the tube bend blank 1 bears
linearly with the bend zone 1.1 against the die 4 or its bend zone
4.1 in the bending zone next to the two pushing rams 2, 3.
[0023] In this connection, the cross-sectional shape of the recess
4.5, which is circular in the region of the two outlet zones 4.2,
4.3, changes in the region of the bend zone 4.1 according to FIG.
1b to an oval cross-sectional shape with the same cross-sectional
area 4.4.
[0024] According to FIG. 2, the tube bend blank 1 is shaped into
the tube bend and has the shape of the recess 4.5. In addition to
the additional radial shaping 5 in the region of the second recess
6 of the die 4, the tube bend blank 1 has in the region of the two
outlet zones 1.2, 1.3 been enlarged to the diameter of the recess
4.5 and has in the region of the two outlet zones 1.2, 1.3 a
corresponding circular cross-sectional shape (not illustrated
further). In the region of the bend zone 1.1, the tube bend blank 1
has according to FIG. 2b been shaped ovally according to the oval
shape of the recess 4.5, the degree of expansion being designed to
be equal to 1 parallel to the bending plane and to increase to a
minimum dimension, that is maximum forming, in the direction at
right angles to the bending plane.
[0025] During the shaping operation, the tube bend blank 1 is acted
on with axial pressure via the pushing rams 2, 3, with which
sufficient material flow for the forming, in particular in the
region of the second recess 6 or other recesses not illustrated
here, is guaranteed. During the axial pressure action by the
pushing rams 2, 3, the tube bend bears against the die 4 or its
bend zone 4.1 with the bend zone 1.1 in the bending plane.
* * * * *