U.S. patent application number 14/866810 was filed with the patent office on 2018-10-18 for butt jointed closed section hollow structural element.
This patent application is currently assigned to MULTIMATIC INC.. The applicant listed for this patent is Rudolf Gruber. Invention is credited to Rudolf Gruber.
Application Number | 20180297149 14/866810 |
Document ID | / |
Family ID | 49756187 |
Filed Date | 2018-10-18 |
United States Patent
Application |
20180297149 |
Kind Code |
A9 |
Gruber; Rudolf |
October 18, 2018 |
BUTT JOINTED CLOSED SECTION HOLLOW STRUCTURAL ELEMENT
Abstract
A method is provided which forms a closed section hollow
structural element by performing the following steps which include
press forming an upper sheet metal component configured with two
primary parallel downstanding interface flanges; press forming a
lower sheet metal component configured with two primary parallel
upstanding interface flanges; complementarily trimming the
downstanding interface flanges and the upstanding interface flanges
using five-axis laser cutting; and butt welding the interface
flanges of the upper and lower sheet metal components to one
another to form a continuous hollow structural element of variable
cross section.
Inventors: |
Gruber; Rudolf; (Uxbridge,
CA) |
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Applicant: |
Name |
City |
State |
Country |
Type |
Gruber; Rudolf |
Uxbridge |
|
CA |
|
|
Assignee: |
MULTIMATIC INC.
Markham
CA
|
Prior
Publication: |
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Document Identifier |
Publication Date |
|
US 20160016260 A1 |
January 21, 2016 |
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|
Family ID: |
49756187 |
Appl. No.: |
14/866810 |
Filed: |
September 25, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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13525337 |
Jun 17, 2012 |
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14866810 |
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PCT/IB2010/055898 |
Dec 16, 2010 |
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13525337 |
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61287662 |
Dec 17, 2009 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
Y10T 29/49893 20150115;
B62D 21/11 20130101; B23K 26/28 20130101; B23K 2101/006 20180801;
B23K 26/38 20130101; Y10T 428/12354 20150115; B23K 2101/045
20180801 |
International
Class: |
B23K 26/28 20060101
B23K026/28; B23K 26/38 20060101 B23K026/38 |
Claims
1. A method of forming a closed section hollow structural element
comprising: press forming an upper sheet metal component with a
generally open section and configured with two primary parallel
downstanding interface flanges; press forming a lower sheet metal
component with a generally open section and configured with two
primary parallel upstanding interface flanges; complementarily
trimming the downstanding interface flanges and the upstanding
interface flanges using five-axis laser cutting; and butt welding
the interface flanges of the upper and lower sheet metal components
to one another to form a continuous hollow structural element of
variable cross section.
2. The method of forming a closed section hollow structural element
as defined in claim 1, wherein the upper and lower sheet metal
components are held in dimensional compliance in a fixture during
the step of complementarily trimming the downstanding interface
flanges and the upstanding interface flanges.
3. The method of forming a closed section hollow structural element
as defined in claim 1, wherein the trimmed edges of the upper and
lower components are welded to one another by a continuous laser
butt weld.
4. The method as defined in claim 2, which further comprises
subsequent to complimentary trimming of the interface flanges,
moving the upper sheet metal component and the lower sheet metal
component into contact with each other while continuing to rigidly
hold them in the fixture, and structurally attaching the components
along the interface by a butt weld while rigidly holding the
components in a fixture.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This patent application claims priority to PCT Application
No. PCT/182010/055898 filed Dec. 10, 2010 and to U.S. provisional
patent application No. 61/287662 filed Dec. 17, 2009. This patent
application is a divisional of Ser. No. 13/525,337 filed on Jun.
17, 2012.
BACKGROUND
[0002] It would be advantageous to create a vehicular structural
member such as a motor compartment rail, suspension control arm or
suspension subframe beam from a closed section hollow element that
utilizes a conventional clamshell configuration but eliminates the
overlapped joint of the prior art. It has been proven that for
large volume applications such as those dictated by the automotive
industry. Sheet metal press forming is the most cost-effective
method of manufacturing structural components. Almost every vehicle
currently produced utilizes a body structure and selected subframes
constructed almost entirely from either aluminum or steel stampings
manufactured using press forming techniques. Wherever closed
section hollow elements are required they are generally constructed
from two press formed open section sheet metal components, creating
a clamshell configuration using either an overlapping section to
facilitate a suitable fillet type weld joint or a outstanding
flange to provide a double material spot weld joint. The primary
aim of the present disclosure is to eliminate the redundant
material associated with overlapping or flange type joints in
clamshell closed section hollow elements.
[0003] The most efficient type of weld joint is a butt arrangement
where the two components being structurally joined meet along a
tangent interface at their open edges so that there is no
overlapping of material. This butt joint can then be welded using
MIG, TIG, Arc, Laser or similar means creating a continuous
structural attachment of the two components. The quality of this
welded butt joint is extremely sensitive to the gap between to the
two components and the differential thickness of the materials of
the two components. The differential thickness can be controlled by
correct specification during the design process. The gap between
the two components is dependent on manufacturing process
capability. When the two components are constructed from stamped
sheet metal using press formed techniques the open edges cannot be
developed to interface with a zero gap due to limitations in the
process. It is for this reason that press formed clamshell
configurations use either an overlapping section to facilitate a
suitable fillet type weld joint or an outstanding flange to provide
a double material spot weld joint.
SUMMARY
[0004] The most effective process for continuous structural
attachment of two metal components is laser welding as laser
welding imparts significantly less heat than other welding
techniques. Laser welding also generally does not require filler
material and has significantly faster application speed. However,
laser welding requires even tighter tolerances on butt joint gaps
than other welding techniques and so is generally only applied to
overlapping material configurations. A closed section hollow
element constructed from two press formed open section sheet metal
components configured as a clamshell with structural attachment
created by laser welding of a butt joint at the interface between
the components would offer a significant weight and cost advantage
over the configurations of the prior art.
[0005] In an embodiment of the present disclosure, a closed section
hollow element is constructed from an upper sheet metal stamped
component with a generally open section manufactured using press
forming techniques and configured with two primarily parallel
downstanding interface flanges and a lower sheet metal stamped
component with a generally open section manufactured using press
forming techniques and configured with two primarily parallel
upstanding interface flanges. After press forming the upper sheet
metal stamped component and lower sheet metal stamped component are
rigidly held in dimensional compliance by a purpose built fixture
and the upstanding and downstanding interface flanges are
complementarily trimmed using five-axis laser cutting. The fixture
facilitates movement of the upper sheet metal stamped component and
lower sheet metal stamped component into contact with each other
along their entire interface with a zero gap while continuing to
rigidly hold the components in dimensional compliance. The upper
sheet metal stamped component and lower sheet metal stamped
component are then structurally attached along the zero gap
interface by a continuous laser butt weld while being rigidly held
in the fixture. Because the components are rigidly held in
dimensional compliance and the five axes trimming operation is
undertaken in the same fixture the zero gap interface is absolutely
maintained and a high quality laser welded joint with no redundant
material overlap, very little heat effect and high processing speed
is achieved. The result is a continuous hollow structural element
of a variable cross section that has a high level of dimensional
integrity because once the two sheet metal stamped components are
structurally attached they hold each other in dimensional
compliance once removed from the fixture thereby eliminating the
effects of material springbuck and forming inaccuracies in the
individual components.
[0006] In this manner, a highly efficient closed section hollow
element is created that utilizes less material than structurally
equivalent overlapped or flanged clamshell configurations thereby
achieving a lower mass and lower cost solution. Additionally the
closed section hollow element of the present disclosure can be
constructed with cost effective press forming tools because highly
accurate sheet metal stamped components are no longer required as
the fixture provides the required dimensional tolerances during
trimming and welding. An additional advantage of the closed section
hollow element of the present disclosure is that its cross section
area can be greatly varied along its length with far higher ratios
than conventional closed section, non-overlapping joint
arrangements produced by roll forming, blow forming or
hydroforming.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a perspective view of the inventive closed section
hollow element;
[0008] FIG. 2 is an expanded perspective view of the inventive
closed section hollow element;
[0009] FIG. 3 is a perspective view of the components of the
inventive closed section hollow element partially installed in the
purpose built fixture;
[0010] FIG. 4 is a perspective view of the purpose built fixture
with the components of the inventive closed section hollow element
fully installed and trimmed;
[0011] FIG. 5 is a perspective view of the purpose built fixture
with the components of the inventive closed section hollow element
fully installed during laser welding;
[0012] FIG. 6 is a perspective view of an application of the
inventive closed section hollow element;
[0013] FIG. 7 is a perspective view of a further application of the
inventive closed section hollow element;
[0014] FIG. 8 is a perspective view of another application of the
inventive closed section hollow element.
DETAILED DESCRIPTION
[0015] Referring to FIGS. 1 and 2, a closed section hollow element
(1) is substantially constructed from an upper sheet metal stamped
component (10) and a lower sheet metal stamped component (20). Both
of the sheet metal stamped components are manufactured by press
forming a flat sheet of steel, aluminum or other suitable metal or
alloy into a required open section shape which is dictated by the
final application's structural and packaging requirements. The
upper sheet metal stamped component (10) is configured with two
primarily parallel downstanding interface flanges (12)(14). As
shown in the non-limiting example of FIGS. 1 and 2, the lower sheet
metal stamped component (20) is configured with two primarily
parallel upstanding interface flanges (22)(24). The downstanding
interface flanges (12)(14) of the upper sheet metal component (10)
are five-axes laser trimmed after press forming to create highly
accurate interface edges (16)(18). The upstanding interface flanges
(22)(24) of the lower sheet metal component (20) are five-axes
laser trimmed after press forming to create highly accurate
interface edges (26)(28). The interface edges (16)(18)(26)(28) are
complementarily trimmed via a five-axes laser during a single
operation while the upper sheet metal stamped component (10) and a
lower sheet metal stamped component (20) are rigidly held in
dimensional compliance by a purpose built fixture. In this manner
the interface edges (26)(28) of the upstanding interface flanges
(22)(24) and the interface edges (16)(18) of the downstanding
interface flanges (12)(14) are configured to tightly match with a
zero gap. This zero gap interface (also referred to as "interface")
facilitates a high quality non-linear weld (30) that structurally
attaches the upper sheet metal stamped component (10) and a lower
sheet metal stamped component (20) so as to create a continuous
hollow structural element (1) having a variable cross section.
[0016] FIG. 3 illustrates a non-limiting example of a purpose built
fixture (40) configured to rigidly hold the upper sheet metal
stamped component (10) and lower sheet metal stamped component (20)
with the sheet metal stamped components shown prior to installation
in the purpose built fixture (40) held at a pre-determined distance
by the spacer blocks (42). FIG. 4 illustrates the purpose built
fixture (40) with the upper sheet metal stamped component (10) and
lower sheet metal stamped component (20) fully installed in the
fixture (40) and the interface edges (16)(18)(26)(28) having been
complementarily trimmed via a five-axes laser. The scrap material
(50)(52) that contains inaccurate formed edges (54)(56) is shown
detached from the interface flanges (12)(14)(22)(24).
[0017] FIG. 5 illustrates the purpose built fixture (40) with the
spacer blocks retracted (42) and the upper sheet metal stamped
component (10) and lower sheet metal stamped component (20) brought
into contact with each other along their previously laser trimmed
interface edges (16)(18)(26)(28) creating a zero gap condition. A
laser beam (60) is illustrated completing a welded butt joint (30)
by butt welding along the entire zero gap interface so as to create
a continuous hollow structural element (1) of a variable cross
section.
[0018] FIG. 6 illustrates a non-limiting example of a vehicular
suspension arm (70) configured as a closed section hollow element
of a variable cross section constructed using the manufacturing
technique previously described.
[0019] FIG. 7 illustrates a non-limiting example of a vehicular
motor compartment rail (72) configured as a closed section hollow
element of a variable cross section constructed using the
manufacturing technique previously described.
[0020] FIG. 8 illustrates a non-limiting example of a vehicular
suspension subframe (74) configured from four closed section hollow
elements of variable cross section constructed using the
manufacturing technique previously described.
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