Information
-
Patent Grant
-
6484547
-
Patent Number
6,484,547
-
Date Filed
Friday, February 23, 200123 years ago
-
Date Issued
Tuesday, November 26, 200221 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Jones, Tullar & Cooper, P.C.
-
CPC
-
US Classifications
Field of Search
US
- 072 71
- 072 82
- 072 83
- 072 84
- 072 86
-
International Classifications
-
Abstract
In the present invention, a thin and disc-shaped blank made of steel plate is used. The present invention provides a method of manufacturing a sheet metal member comprising a circular base plate, and an annular projection bulged from at least one surface of the base plate so as to be concentric therewith, which can be easily and cheaply produced without loss of material, by only a few steps. A blank having an outer peripheral portion which has been thickened by a former step, is rotated while it is held between an upper and lower dies. At the same time, an edge angle portion of an outer peripheral surface of a drawing roller is pressed against one surface of the thickened outer peripheral portion which extrudes outwardly from the upper die of the blank, and the drawing roller is rotated, while it is moved in the direction of the center of the blank, and the thickened outer peripheral portion is drawn so as to make it think, thereby bulging the annular projection axially.
Description
TECHNICAL FIELD
This application is a 35 USC 371 of PCT/JP99/04032 filed Jul. 28, 1999.
The present invention relates to a thin sheet metal member having a predetermined shape, and especially, a sheet metal member which is available as a partition of a gas generator of an air bag used for an automobile, and a method of manufacturing the same.
BACKGROUND ART
Conventionally, a thin disc-shaped blank having the substantial thickness of 0.4 to 1.2 mm has been used. There has never been a sheet metal member which is formed so as to comprise a circular base plate and an annular projection concentrically and integrally formed with one or both surfaces of the circular base plate, in a bulged state, and a processing technology thereof.
The present invention has an object to provide a sheet metal member which is formed so as to have a circular base plate and an annular projection integrally formed with one or both surfaces of the thin and circular base plate in a bulged state, so as to be concentric with each other, and a method of manufacturing the same.
Moreover, the present invention has another object to provide a sheet metal member having the above shape, which is lightweight and durable.
Furthermore, the present invention has still another object to provide a method of manufacturing a sheet metal member which is formed so as to have a circular base plate and an annular projection concentrically and integrally formed with one or both surfaces of the thin and circular base plate, in a bulged state, using minimum steps. The method thereof can achieve reduction of material without producing cutting waste, and make it easy to produce the sheet metal member economically.
SUMMARY OF THE INVENTION
According to the present invention, a sheet metal member, which is made from a thin disc-shaped blank, is characterized in that an annular projection is integrally formed with at least one surface of a circular base plate, so as to be concentric with each other, and said annular projection is formed by drawing an outer peripheral portion of the base plate so as to decrease a thickness of the outer peripheral portion of the base plate, and axially bulging it.
The sheet metal member having the above structure is lightweight and durable.
According to the present invention, a method of manufacturing a sheet metal member, which is made from a thin disc-shaped blank, wherein an annular projection is integrally formed with at least one surface of a circular base plate so as to be concentric with each other, comprises the steps of:
rotating the thin disc-shaped blank in a state of holding the thin disc-shaped blank between upper and lower dies, at the same time while pressing a groove on an outer peripheral surface of a thickening-forming roller, against an outer peripheral portion of the blank which extrudes outwardly from the upper and lower dies, thereby thickening the outer peripheral portion of the blank; and
rotating the blank which have a thickened outer peripheral portion in a state of holding it between another upper and lower dies, at the same time while pressing an edge angle portion of an outer peripheral surface of a drawing roller against one surface of the thickened outer peripheral portion which extrudes outwardly from the upper die of the blank, and rotating the drawing roller, and
drawing the thickened outer peripheral portion thereof so as to make it thin, while moving it in the direction of the center of the blank, thereby bulging the annular projection axially.
According to the above manufacturing method, the thin and circular blank is used, and it is subjected to rotation-drawing process by means of the drawing roller. As a result, the sheet metal member which has an annular projection concentrically and integrally formed with at least one surface of the circular base plate, can be easily and economically obtained by only a few steps, because cutting waste is never produced from the material.
The drawing roller draws one surface of the thickened outer peripheral portion at the edge angle by providing a clearance angle for providing a clearance so as to prevent a lower surface of the drawing roller opposed to the drawing surface of the thickened outer peripheral portion from abutting against the drawing surface.
This can prevent the lower surface of the drawing roller from being burnt on the drawing surface of the thickened outer peripheral portion. Furthermore, this makes it easy to perform the drawing process.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a sectional view of a sheet metal member according to the present invention.
FIGS. 2A
to
2
F are diagrams of processes of manufacturing a sheet metal member according to the present invention.
BEST MODES FOR CARRYING OUT THE INVENTION
A sheet metal member according to the present invention is made from a thin disc-shaped steel sheet blank. As shown in
FIG. 1
, a boss portion
2
is protrusively integrated with a center of a circular base plate
1
, and annular projections
3
,
4
which are bulged, are respectively concentrically integrated with one and the other surfaces of the base plate
1
. The annular projections
3
,
4
are shaped by rotatively drawing the preliminarily thickened outer peripheral portion of the base plate
1
, so as to be thinned, thereby axially bulging them.
The sheet metal member, having the above structure, is lightweight, strong and extremely durable. For example, the sheet metal member is suitable for various kinds of mechanical parts including a partition of a gas generator of an air bag used for an automobile, or the like.
Next, an embodiment of a method of manufacturing the sheet metal member will be described with reference to with reference to
FIGS. 2A
to
2
F.
FIGS. 2A and 2B
show a first step.
FIG. 2A
shows a state previous to applying a process of the first step.
FIG. 2B
shows a state after applying the process thereof. A blank
10
, upper and lower dies
11
,
12
and a thickening-forming roller
13
are shaped in a state of rotation symmetry. Therefore, it is illustrated in a half section view.
In this step, the thin circular blank (material)
10
is employed. The boss
2
is protrusively integrated with a center of the blank by means of previous press-shaping. As shown in
FIG. 2B
, the blank
10
is held between the upper and lower dies
11
,
12
, to be rotated around O
1
by driving. A thickening-forming roller
13
includes a groove
13
a
whose section has a V-shape or a circular shape on an outer peripheral surface thereof The groove
13
a is strongly pressed against an outer peripheral portion
10
a
which extrudes outwardly from the upper and lower dies
11
,
12
of the blank
10
, in a radially inward direction thereof while the thickening-forming roller
13
is rotated around O
2
in a reverse direction of rotation of the blank
10
so as to follow the rotation of the blank
10
, thereby thickening the outer peripheral portion
10
a
of the blank
10
. Such thickening is attributed to flow of a material of the outer peripheral portion
10
a
which is caused inside the groove
13
a
by pressing the thickening-forming roller
13
.
FIGS. 2C and 2D
show a second step.
FIG. 2C
shows a state previous to applying a process of the second step.
FIG. 2B
shows a state after applying it. In the second step, as shown in
FIG. 2C
, the blank
10
having the thickened outer peripheral portion
10
a
obtained by the first step is held between the upper and lower dies
14
and
15
, while it is rotated around O
1
by driving. At the same time, an edge angle portion
16
a
of the outer peripheral surface of a drawing roller
16
is strongly pressed against one surface of the thickened outer peripheral portion
10
a
which extends outwardly from the upper die
14
of the blank
10
, and the drawing roller
16
is rotated around O
2
in a reverse direction of rotation of the blank
10
so as to follow the rotation of the blank
10
. Moreover, while it is moved in a direction of the center of the blank
10
, the thickened outer peripheral portion
10
a
is drawn so as to be thin. As a result, the material disposed in front of the outer peripheral surface of the drawing roller
16
is gradually bulged in the axial direction, thereby cold forming the annular projection
3
on one surface of the blank
10
between an outer peripheral portion
14
a
of the upper die
14
and the outer peripheral portion of the drawing roller
16
.
The edge angle portion
16
a
of the drawing roller
16
and an edge angle portion
14
b
of a lower end of the outer peripheral portion
14
a
of the upper die
14
are respectively rounded. Therefore, root portions of the annular projection
3
are rounded according thereto.
In this case, the drawing roller
16
has a clearance angle α (for example, substantially 5°) by means of inclining the rotation axis O
2
, substantially at an angle 5° with the vertical direction, so as to prevent the lower surface
16
b
of the drawing roller
16
from abutting against the drawing surface of the thickened outer peripheral portion
10
a
. This can prevent a lower surface
16
b
of the drawing roller
16
from being burnt on the drawing surface. Additionally, this makes it possible to draw easily one surface of the thickened outer peripheral portion
10
a
at the edge angle portion
16
a
of the drawing roller
16
.
FIGS. 2E and 2F
show a third step.
FIG. 2E
shows a state prior to applying a process of the third step.
FIG. 2F
shows a state after applying it. In the third step, the blank
10
obtained by the second step is reversed, whereby it is held between upper and lower dies
17
and
18
, while it is rotated around O
1
, by driving. At the same time, an edge angle portion
19
a
of an outer peripheral surface of a drawing roller
19
is strongly pressed against the other surface of the thickened outer peripheral portion
10
a
which extrudes outwardly from the upper die
17
of the blank
10
, and the drawing roller
19
is rotated around
02
in a reverse direction of rotation of the blank
10
so as to follow the rotation of the blank
10
. Moreover, while it is moved in the direction of the center of the blank
10
, the other surface of the thickened outer peripheral portion
10
a
is drawn so as to be thin. As a result, the annular projection
4
is axially bulged on the other surface of the blank
10
between the outer peripheral surface of the drawing roller
19
and the outer peripheral portion
17
a
of the upper die
17
, so as to be cold formed. In this case, the drawing roller
19
has also the clearance angle α between the lower surface
19
b
of the drawing roller
19
and the drawing surface of the thickened outer peripheral portion
10
a
, in the same manner as the second step.
Finally, a conical portion around the boss portion
2
of the blank
10
is formed by pressing, thereby shaping it into the flat base plate
1
. Thus, a finish product as the sheet metal member as shown in
FIG. 1
can be obtained.
According to the above manufacturing method, for example, the blank
10
is employed, whose thickness to is 0.8 mm, as shown in FIG.
1
. As a result, the annular projection
3
which has an outer diameter D
1
of 56.8 mm, a thickness t
1
of 0.3 mm, and a height h
1
of 3 mm, and the annular projection
4
which has an outer diameter D
2
of 55.6 mm, a thickness t
2
of 0.3 mm, and a height h
2
of
2
mm can be formed respectively on one and the other surfaces of the base plate
1
having a diameter of 69.5 mm.
Though, in the above embodiment, the annular projections
3
,
4
are respectively formed on either side of the base plate
1
, it is needless to say that the embodiment can be also applied to the case of forming the annular projection on only one side thereof. Moreover, the thin circular-shaped blank
10
made of steel sheet to be used is not limited to blank which has been previously bent so as to be conical. So, a flat thin circular blank
10
may be used as it is.
INDUSTRIAL APPLICABILITY
According to the present invention, a sheet metal member comprises a thin and circular base plate, and annular projections bulged from at least one surface of the base plate so as to be concentric therewith. The sheet metal member having the above structure is lightweight, and extremely durable. For example, the sheet metal member is suitable for various kinds of mechanical parts including a partition of a gas generator of an air bag used for an automobile, or the like.
A sheet metal member comprising a thin and circular base plate, and annular projections bulged from at least one surface of the base plate so as to be concentric with each other can be easily and cheaply produced without loss of the material, by only a few steps according to the present invention.
Claims
- 1. A method of manufacturing a sheet metal member, which is made from a thin disc-shaped blank defining a center, wherein an annular projection is integrally formed with at least one surface of a circular base plate from the thin disc-shaped blank so as to be concentric with each other, comprising the steps of:holding and rotating the thin disc-shaped blank between upper and lower dies, at the same time while pressing a groove on an outer peripheral surface of a thickening-forming roller, against an outer peripheral portion of the blank which extrudes outwardly from the upper and lower dies, thereby forming a thickened outer peripheral portion of the blank; holding and rotating the blank with the thickened outer peripheral portion between another upper and lower dies, at the same time while pressing an edge angle portion of an outer peripheral surface of a drawing roller against one surface of the thickened outer peripheral portion which extrudes outwardly from the upper die of the blank, and rotating the drawing roller, and drawing the thickened outer peripheral portion while moving the drawing roller in the direction of the center of the blank, thereby bulging the annular projection axially.
- 2. A method of manufacturing a sheet metal member according to claim 1, wherein the drawing roller draws one surface of the thickened outer peripheral portion at the edge angle by providing a clearance angle so as to prevent a lower surface of the drawing roller opposed to the drawing surface of the thickened outer peripheral portion from abutting against the drawing surface.
PCT Information
Filing Document |
Filing Date |
Country |
Kind |
PCT/JP99/04032 |
|
WO |
00 |
Publishing Document |
Publishing Date |
Country |
Kind |
WO01/07181 |
2/1/2001 |
WO |
A |
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Number |
Name |
Date |
Kind |
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Adams et al. |
Aug 1966 |
A |
5619879 |
Friese |
Apr 1997 |
A |
5987952 |
Kutzscher et al. |
Nov 1999 |
A |
6012318 |
Kanemitsu et al. |
Jan 2000 |
A |
6105410 |
Sauberlich et al. |
Aug 2000 |
A |
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Number |
Date |
Country |
61-129241 |
Jun 1986 |
JP |
1-278919 |
Nov 1989 |
JP |
4-52039 |
Feb 1992 |
JP |
2719563 |
Nov 1997 |
JP |
11-169986 |
Jun 1999 |
JP |