Metal working – Method of mechanical manufacture – Heat exchanger or boiler making
Reexamination Certificate
1999-08-11
2002-04-23
Rosenbaum, I Cuda (Department: 3726)
Metal working
Method of mechanical manufacture
Heat exchanger or boiler making
C029S557000, C072S334000
Reexamination Certificate
active
06374490
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method of forming a hollow pole projecting on a plate such as a metal plate to which various components are to be attached or which is to support a rotating member, and a method of forming heat dissipating fins by utilizing the aforementioned hollow poles in order to dissipate heat away from electronic components generating said heat in an effective manner by providing the heat dissipating fins in the vicinity of the electronic components.
DESCRIPTION OF THE PRIOR ART
In order to axially support a rotating part or axially affix other parts to a plate such as a metal plate, a hole is bored in the plate and a specially manufactured axial member is then passed through the hole. The axial member is then fixed using end fixing means or using a screw.
However, the number of components required when an axial member is separately made and fixed to a plate is large, as is the number of manufacturing steps, and high costs are therefore inevitable. Because of this, in Japanese Patent Laid-open Publication No. Hei. 6-26737, the present applicant proposed a method of integrally forming a cylindrical projection by utilizing plastic processing technology, which was extremely useful in practical terms.
FIG.
9
and
FIG. 10
are views showing a method of forming a cylindrical projection at a plate proposed in the related art, where
FIG. 9
is a view showing a method of forming a cylindrical projection having a bottom in the plate. First, in a first press step #
10
, a press tool
401
that is a circular column formed with a flat end surface is pushed against one surface of a plate
400
comprising a metal plate of a metal having plasticity such as iron or aluminum so as to form a hole
102
at the one side and a projection
403
at the other side.
Next, in a flat press step #
11
, the end surface of a columnar flat press tool
404
of an external diameter greater than the external diameter of the projection
403
is brought into contact with the side of the opening of the hole
402
and pressed. As a result, the metal of the pressed portion moves towards a central section
405
of the hole
402
that provides no resistance and is also moved to the projection
403
so that the projection
403
is made to project further.
In a second press step #
12
, the plate
400
that has undergone the flat press step #
11
is again pressed by the press tool
401
from the side of the opening and the height of the projection is further increased so as to form a cylindrical projection
406
at the plate
400
. The height of the cylindrical projection
406
is then two times a thickness t
1
of the plate
400
or more.
FIG. 10
is a view showing a method of forming a cylindrical projection that penetrates the plate from one side to the other. Namely, up to the flat press step #
11
, the steps shown in
FIG. 9
are gone through. Thereafter, a boring step is provided. Here, a boring tool
407
having a stem portion of a small diameter is inserted through the hole
402
and punching is carried out so as to bore a thruhole
408
. Next, in a burring step #
14
, a burring tool
409
with a tapered front end and an external diameter that is the same as the diameter of the press tool
401
is inserted from the hole
402
and passed through while broadening out the thruhole
408
so as to form a cylindrical projection
410
having a height L
02
. In the method shown in
FIG. 10
a height L
02
of the cylindrical projection
410
is also formed to be at least twice the thickness t
1
of the plate
400
.
In the methods of forming a cylindrical projection at a plate described above, the cylindrical projection
406
are integrally formed at the sheet
400
. Costs are therefore reduced and cylindrical projection having a height of twice the thickness of the plate
400
or more can be formed at the plate
400
. There is a limit on making the cylindrical projection substantially larger with respect to the thickness t
1
of the plate
400
in that the direction of the movement of the metal due to pressing by the flat press tool
404
is dispersed. There are also cases where a thick projection is required but there are limits when the thickness is increased in the related axial part forming method for the reasons state above.
As the present invention sets out to resolve the aforementioned problems of the related forming methods, it is the object of the present invention to provide a method of forming a cylindrical projection, which is substantially a hollow pole, in a plate where the hollow pole can be made substantially higher with respect to the thickness of the plate or where the thickness of the hollow pole is made thicker.
It is also a further object of the present invention to provide a method of easily and cheaply manufacturing a heatsink with superior heat dissipating effects by forming one or more heat dissipating fins utilizing the aforementioned hollow pole, and to provide a heatsink thereof.
SUMMARY OF THE INVENTION
In order to achieve the aforementioned object, according to the present invention, there is provided a method of forming a hollow pole projecting from a metal plate by plastic deformation and comprising the steps of: (a) pressing the plate from one surface of the plate using a press tool so as to form a hole on the one surface and a projection on the other surface thereof; (b) moving metal of the plate around said projection towards interior of said hole so as to gather the metal into a periphery of an opening of said hole using a tapered tool; (c) pressing said periphery of said hole using a flat press tool which is greater than said projection in an external diameter so as to move the metal gathered by said tapered tool further towards the interior of said hole and to increase a height of said projection; and (d) inserting said press tool into said hole while pressing the interior of said hole so as to increase further the height of said projection and to form the hollow pole. The projection can therefore be made substantially higher with respect to the thickness of the plate or the thickness of the hollow pole can be made thicker. Further, a heatsink utilizing the hollow poles as superior heat dissipating fins can be manufactured easily and cheaply.
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Cuda Rosenbaum I
Flynn ,Thiel, Boutell & Tanis, P.C.
Nakamura Seisakusho Kabushikigaisha
Nguyen T.
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