U.S. patent application number 11/659486 was filed with the patent office on 2009-05-21 for method and apparatus for manufacturing a rim bed by means of cold forming.
This patent application is currently assigned to Fontijne Grotnes B.V.. Invention is credited to Khalid Tachi.
Application Number | 20090126443 11/659486 |
Document ID | / |
Family ID | 34974401 |
Filed Date | 2009-05-21 |
United States Patent
Application |
20090126443 |
Kind Code |
A1 |
Tachi; Khalid |
May 21, 2009 |
METHOD AND APPARATUS FOR MANUFACTURING A RIM BED BY MEANS OF COLD
FORMING
Abstract
A method for manufacturing a substantially rotationally
symmetric rim bed having a wall thickness varying along the
longitudinal axis by means of cold forming, wherein the side walls
of a substantially cylindrical metal bed having a substantially
constant wall thickness are flared radially outwards in a pressing
operation, and wherein the wall thickness of the flared side walls
is varied along the longitudinal axis by means of flow-spinning,
with axial stretching and profiling of the sides. The invention
further relates to an apparatus for manufacturing a rim bed by
means of cold forming.
Inventors: |
Tachi; Khalid; (IJssel,
NL) |
Correspondence
Address: |
PATENT GROUP;C/O DLA PIPER US LLP
203 N. LASALLE ST., SUITE 1900
CHICAGO
IL
60601
US
|
Assignee: |
Fontijne Grotnes B.V.
Vlaadingen
NL
|
Family ID: |
34974401 |
Appl. No.: |
11/659486 |
Filed: |
August 5, 2005 |
PCT Filed: |
August 5, 2005 |
PCT NO: |
PCT/NL2005/000575 |
371 Date: |
February 6, 2009 |
Current U.S.
Class: |
72/250 ;
72/365.2 |
Current CPC
Class: |
B21D 22/16 20130101;
B21D 53/30 20130101 |
Class at
Publication: |
72/250 ;
72/365.2 |
International
Class: |
B21B 39/20 20060101
B21B039/20; B21D 31/00 20060101 B21D031/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 6, 2004 |
NL |
1026796 |
Claims
1. A method for manufacturing a substantially rotationally
symmetric rim bed having a wall thickness varying along the
longitudinal axis by means of cold forming, wherein the side walls
of a substantially cylindrical metal bed having a substantially
constant wall thickness are flared radially outwards in a pressing
operation, and wherein the wall thickness of the flared side walls
is varied along the longitudinal axis by means of flow-spinning,
with axial stretching and profiling of the sides.
2. A method according to claim 1, wherein, during flow-spinning,
the flared side walls of the bed are pressed down from a free
position on a mandrel.
3. A method according to claim 1, wherein, during flow-spinning, in
a first flow-spinning step, the bed is pressed down on a mandrel
near the center of the length of the longitudinal axis.
4. A method according to claim 3, wherein, during flow-spinning, in
a second processing step, the bed is axially stretched, radially
thinned and profiled from the center area of the longitudinal axis
in two opposite, outwardly directed movements with radial pressing
down on a mandrel.
5. A method according to, claim 1 wherein the pre-profiled,
flow-spun bed is rolled to a rim bed by means of roll forming.
6. A method according to claim 1, wherein the bed is only radially
expanded after flow-spinning and optionally roll forming.
7. An apparatus for manufacturing a substantially rotationally
symmetric rim bed having a wall thickness varying along the
longitudinal axis by means of cold forming, wherein a substantially
cylindrical metal bed having a substantially constant wall
thickness is provided with sides flared radially outwards in a
pressing operation, and wherein the wall thickness of the flared
sides is varied along the longitudinal axis by means of
flow-spinning, with axial stretching and profiling of the
sides.
8. An apparatus according to claim 7, wherein, during
flow-spinning, the flared side walls of the bed are pressed down
from a free position on a mandrel.
9. An apparatus according to claim 8, wherein a pressing station is
provided for radially outward flaring of the sides of a cylindrical
bed.
10. An apparatus according to claim 8, wherein a flow-spinning
station is provided for profiling and axially stretching the flared
bed.
11. An apparatus according to claim 10, wherein the flow-spinning
station connects downstream to the pressing station.
12. An apparatus according to claim 10, wherein the flow-spinning
station is located upstream of a rolling station for rolling the
pre-profiled, flow-spun bed to a rim bed.
Description
[0001] The invention relates to a method for manufacturing a
substantially rotationally symmetric rim bed having a wall
thickness varying along the longitudinal axis by means of cold
forming.
[0002] Such a method is known from WO 2004/035243 and is used for
manufacturing a so-called weight-optimized rim bed for a rim for a
tire.
[0003] In such a weight-optimized rim bed, which is, for instance,
used in a rim for a passenger car, truck or trailer, the thickness
of the rim bed varies along the longitudinal axis. Then, at
different locations along the longitudinal axis, the thickness of
the rim bed can be chosen such that this is just sufficient for
absorbing the local loads. Thus, the rim bed may, for instance, be
chosen so as to be relatively thick near the center of its axial
length, in order to weld the rim bed there with the disk of the
rim. In the adjacent areas, the thickness of the rim bed can then,
for instance, be chosen so as to be considerably smaller, whereas
the thickness closer to the sides of the rim is usually chosen so
as to be larger.
[0004] In the known method, the cylindrical steel bed is
pre-pressed from the outsides inwards to the center by means of
flow-spinning. Here, the more outer parts of the bed are brought to
a nominal thickness and any excess material is brought to the
center of the length of the longitudinal axis and the bed is
pre-profiled. Then, in a second flow-spinning operation, in two
movements, the bed is stretched from the center axially outwards
towards the sides at locations where the thickness of the rim bed
needs to be reduced.
[0005] Compared to a manufacturing process in which the
flow-spinning takes place after rolling the profile, as described
in DE 2647464, too great a deformation of the bed material can be
prevented, so that dressing of the sides of the rim bed can be
prevented.
[0006] Over the process described in WO 02/053307, in which, during
flow-spinning, the bed is processed on a cylindrical mandrel, the
process described in WO 2004/035243 has the advantage that already
some pre-profiling occurs.
[0007] However, a drawback of the method according to WO
2004/035243 is that it still is relatively expensive and
time-consuming.
[0008] Therefore, the invention contemplates a method of the type
stated in the opening paragraph, with which, wile maintaining the
advantages, these drawbacks can be prevented. To this end, the
invention provides a method for manufacturing a substantially
rotationally symmetric rim bed having a wall thickness varying
along the longitudinal axis by means of cold forming, wherein the
side walls of a substantially cylindrical metal bed having a
substantially constant wall thickness are flared radially outwards
in a pressing operation, and wherein the wall thickness of the
flared side walls is varied along the longitudinal axis by means of
flow-spinning, with axial stretching and profiling of the
sides.
[0009] By using a cylindrical metal bed with sides flared radially
outwards, the bed can be pre-profiled, or even finally profiled, in
one flow-spinning step without dressing of the sides being
necessary.
[0010] Preferably, here, the material of the bed can move freely in
feeding direction. In particular, here, during flow-spinning, the
flared side walls of the bed can be pressed from a free position
onto a mandrel. In forward flow-spinning in this manner, the
material still to be deformed runs clear of the mandrel and does
not run against a stop in feeding direction, which yields a
favorable interplay of forces. In particular, a removing operation
can be omitted in forming the cylindrical bed into a brim bed.
[0011] In an advantageous manner, during flow-spinning, in a first
flow-spinning step, the bed is pressed down on a mandrel near the
center area of the length of the longitudinal axis. As a result,
the bed can be positioned well, so that, during further
flow-spinning, a high size and form accuracy can be achieved.
[0012] In an advantageous manner, during flow-spinning, in a second
processing step, the bed is axially stretched, radially thinned and
profiled from the center area of the longitudinal axis in two
opposite, outwardly directed movements with radial pressing down on
a mandrel.
[0013] Here, the flow-spinning is carried out in axially outwardly
directed basic movements from the center area of the longitudinal
axis of the bed towards the respective sides, while the still loose
material to be profiled is pressed down on the mandrel.
[0014] If necessary, the pre-profiled, flow-spun bed can also be
rolled to a rim bed by means of roll forming.
[0015] Preferably, radial expansion of the bed only takes place
after flow-spinning or after the profiling step following
flow-spinning.
[0016] The invention further relates to an apparatus for
manufacturing a substantially rotationally symmetric rim bed having
a wall thickness varying along the longitudinal axis by means of
cold forming, wherein a substantially cylindrical metal bed having
a substantially constant wall thickness is provided with sides
flared radially outwards in a pressing operation, and wherein the
wall thickness of the flared sides is varied along the longitudinal
axis by means of flow-spinning, with axial stretching and profiling
of the sides. The apparatus is preferably provided with a
flow-spinning station for profiling and axially stretching the
flared bed with radial pressing down, and with a pressing station
for radially outward flaring of the sides of a cylindrical bed,
while the flow -spinning station connects downstream to the
pressing station.
[0017] The invention will be explained in more detail with
reference to the exemplary embodiment shown in a drawing.
[0018] In the drawing:
[0019] FIG. 1 shows a flow diagram of a production line for a rim
bed according to the invention;
[0020] FIG. 2A shows a schematic longitudinal cross-section of the
flared cylindrical bed having a thickness substantially constant
along the longitudinal axis;
[0021] FIG. 2B shows a schematic longitudinal cross-section of a
bed which is pre-profiled by means of flow-spinning on the basis of
FIG. 2A, where it is clearly visible that the thickness of the bed
varies along the longitudinal axis 1;
[0022] FIG. 3 shows a schematic longitudinal cross-section of a
pressing station for radially outward flaring of the side walls of
a cylindrical bed;
[0023] FIGS. 4A and 4B show two schematic longitudinal
cross-sections of a flow-spinning station during fixing and
stretching/profiling the bed with flared sides, respectively;
[0024] FIG. 5A shows a schematic side elevational view of three
successive roll formers;
[0025] FIG. 5B shows a schematic longitudinal cross-section of a
roll former in which a pre-profiled bed is profiled; and
[0026] FIG. 6 shows a schematic side elevational view of a radial
expander.
[0027] It is noted that the Figures are only schematic
representations of a preferred embodiment of the invention which
are given exclusively by way of non-limiting exemplary embodiments.
In the Figures, same or corresponding parts are designated by the
same reference numerals.
[0028] FIG. 1 schematically shows a flow diagram for a production
line P for a rim. In a preparation part 1 of the line, metal strips
are cut to length in a first step 1.1 and formed into a cylindrical
bed in a second group of steps 1.2. Here, the strip is successively
coiled (1.2.1) and its front ends are welded to each other (1.2.2),
after which the weld is dressed (1.2.3).
[0029] In a second part 2 of the line, the cylindrical rim bed
having a constant wall thickness formed in part 1 is formed into a
profiled rim bed in a profiling line (2.1) and then tested for
leakage and provided with a valve hole (2.2). The profiling takes
place by means of cold forming of the material, i.e. the material
is not melted and no removing takes place. In a first processing
station 2.1.1, the side walls of the bed are flared radially
outwards to the basic form shown in FIG. 3 in an axially inwardly
directed pressing operation with the aid of mandrels. Then, as will
be elucidated hereinafter, in a second processing station 2.1.2,
the wall thickness of the flared bed is varied along the
longitudinal axis by means of flow-spinning with simultaneous
pre-profiling of the bed.
[0030] Then, in a third processing station 2.1.3, the pre-profiled
bed is profiled to a rim bed by means of roll formers, after which
the profiled bed is radially expanded to the desired size in a
fourth processing station 2.1.4.
[0031] After a check for leaks and provision of the valve hole, the
rim bed is ready to be assembled with the disk to a rim in an
assembly part 3 of the production line. Depending on the type of
rim, the disk is connected with the rim bed at a predetermined
location along the longitudinal axis.
[0032] In FIG. 2A, a longitudinal cross-section of the flared
cylindrical bed 10 having a constant diameter along the
longitudinal axis is shown.
[0033] In FIG. 2B, the pre-profiled bed 20 is shown, while it is
clearly visible that the thickness t of the bed varies over the
length of the longitudinal axis 1.
[0034] In FIG. 4A, the flow-spinning station 2.1.2 is schematically
shown.
[0035] The flow-spinning station is provided with two rotatably
arranged mandrels 11A, 11B which are each axially slidable along
the longitudinal axis 1 of the flared bed 10. In the Figure, the
mandrels 11 are each placed from a side 12A, 12B of the flared bed
10 to the center area M of the length of the longitudinal axis 1 of
the bed. During the sliding in of the mandrels 11A, 11B, the bed is
clamped at its sides 12A, 12B with the aid of slidable stop collars
14.
[0036] The flow-spinning station further comprises one or more
rollers 13 which can move radially with respect to the longitudinal
axis of the bed 10 and which are further translatable with respect
to the longitudinal axis of the bed 10. The rollers 13 are further
rotatably arranged with respect to the flared bed 10. Here, the
rollers 13 and/or the flared bed 10 can rotate with respect to the
fixed world during production.
[0037] FIG. 4A shows how, in a first processing step, the flared
bed 10 is pressed down on the mandrels 11A, 11B near the center
area M of the length l of the longitudinal axis of the bed 10 in a
first flow-spinning step. The thickness t of the center area M
remains substantially equal.
[0038] Then, as shown in FIG. 4B, with the aid of the rollers 13A,
13B, the material of the bed 10 is moved outwards along
longitudinal axis 1 in two successive, opposite movements with
radial pressing down, so that, with axial stretching of the bed 10,
the thickness t of the bed 10 is locally reduced.
[0039] At the same time, the material of the flared side of the bed
10 is pressed down from the free position on the mandrel 11 by the
rollers 13A, 13B, so that the side wall of the bed 10 is
pre-profiled to the pre-profiled bed 20 shown in FIG. 2B. It is
noted that, in the schematic view, the thickness t only varies
little over the longitudinal axis 1. It will be clear that, in
practice, the thickness variation may be greater or smaller than
shown herein. Also, more or fewer areas having different
thicknesses can be formed than shown herein.
[0040] During the processing process, the bed material flows
outwards with respect to the center of the longitudinal axis
towards the side. If desired, during the second processing step,
the sides of the bed 12A, 12B can be supported by means of the
slidable stop collars 14. FIG. 4B, however, shows that the slidable
stop collars do not support the sides 12A, 12B.
[0041] After processing, the stop collars 14 are again brought into
contact with the sides 12A, 12B, after which the mandrels 11A, 11B
are axially withdrawn. With axial withdrawal of the stop collars
14, the pre-profiled bed 20 can then be removed.
[0042] So, in the second processing step shown in FIG. 4B, from the
center, two successive, sideward flow-spinning operations are
carried out. It is of course possible to carry out flow-spinning
operations from the center to both sides simultaneously.
[0043] It is noted that the invention is not limited to the
embodiments shown herein and that many variations are possible
within the scope of the invention as set forth in the following
claims.
* * * * *