U.S. patent application number 16/306806 was filed with the patent office on 2019-07-25 for forging device.
This patent application is currently assigned to SHOWA DENKO K.K.. The applicant listed for this patent is SHOWA DENKO K.K.. Invention is credited to Kazuo IGARASHI.
Application Number | 20190224740 16/306806 |
Document ID | / |
Family ID | 60479519 |
Filed Date | 2019-07-25 |
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United States Patent
Application |
20190224740 |
Kind Code |
A1 |
IGARASHI; Kazuo |
July 25, 2019 |
FORGING DEVICE
Abstract
A forging device produces a forged product in which a protrusion
is formed on a base plate. The forging device has a die with a
molding hole and a punch to be driven into the molding hole. A
protrusion molding cavity is formed in a bottom surface of the
molding hole or a tip end surface of the punch in the die. A base
plate molding portion is formed between the tip end surface of the
punch and the bottom surface of the molding hole. A burr molding
portion is formed between the tip end portion outer peripheral side
surface of the punch and the inner peripheral side surface of the
molding hole. The inner peripheral side surface of the molding hole
is formed by an inclined surface that approaches an axis as it
advances toward the pressing direction of the punch.
Inventors: |
IGARASHI; Kazuo; (Fukushima,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SHOWA DENKO K.K. |
Tokyo |
|
JP |
|
|
Assignee: |
SHOWA DENKO K.K.
Tokyo
JP
|
Family ID: |
60479519 |
Appl. No.: |
16/306806 |
Filed: |
April 21, 2017 |
PCT Filed: |
April 21, 2017 |
PCT NO: |
PCT/JP2017/016021 |
371 Date: |
December 3, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B21C 23/183 20130101;
B21J 9/022 20130101; F28F 3/022 20130101; H01L 23/3677 20130101;
B21J 5/02 20130101; F28F 3/048 20130101; B21J 5/12 20130101; H01L
23/36 20130101; H01L 21/4878 20130101; B21J 13/025 20130101; B21J
13/02 20130101; F28F 2255/08 20130101; B21C 23/06 20130101; B21J
5/022 20130101; B21K 23/00 20130101 |
International
Class: |
B21J 5/02 20060101
B21J005/02; B21J 13/02 20060101 B21J013/02; B21J 9/02 20060101
B21J009/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 3, 2016 |
JP |
2016-111479 |
Claims
1. A forging device for producing a forged product in which a
protrusion is formed on a base plate, comprising: a die having a
molding hole; and a punch to be driven into the molding hole,
wherein a protrusion molding cavity is formed in at least one of a
bottom surface of the molding hole of the die and a tip end surface
of the punch, wherein a base plate molding portion is formed
between the tip end surface of the punch and the bottom surface of
the molding hole, wherein a burr molding portion is formed between
a tip end portion outer peripheral side surface of the punch and an
inner peripheral side surface of the molding hole, and wherein the
inner peripheral side surface of the molding hole is formed by an
inclined surface which is inclined with respect to an axis and
approaches the axis toward a pressing direction of the punch.
2. The forging device as recited in claim 1, wherein a chamfered
portion is formed at an internal corner portion between the inner
peripheral side surface and the bottom surface of the molding
hole.
3. The forging device as recited in claim 1, wherein the tip end
portion outer peripheral side surface of the punch is formed by an
inclined surface which is inclined with respect to the axis and
approaches the axis toward the pressing direction of the punch, and
wherein an inclination angle of the tip end portion outer
peripheral side surface of the punch with respect to the axis is
formed to be equal to or less than an inclination angle of the
inner peripheral side surface of the molding hole with respect to
the axis.
4. The forging device as recited in claim 1, wherein a chamfered
portion is formed at an external corner portion between the tip end
portion outer peripheral side surface and the tip end surface of
the punch.
5. The forging device as recited in claim 1, wherein an external
corner portion between the tip end portion outer peripheral side
surface and the tip end surface of the punch is arranged at a
position closer to the axis than the internal corner portion
between the inner peripheral side surface and the bottom surface of
the molding hole.
6. The forging device as recited in claim 1, wherein the protrusion
molding cavity is constituted by a fin molding cavity for molding a
fin of a heat sink.
7. A forging method for producing a forged product in which a
protrusion is formed on a base plate, comprising: a step of setting
a forging material in a molding hole of a die formed by an inclined
surface in which an inner peripheral side surface of a molding hole
is inclined with respect to an axis and approaches the axis toward
an inner portion of the molding hole; and a step of pressurizing
the forging material by driving a punch into the molding hole;
wherein in the step of pressurizing the forging material, a
protrusion is formed by a protrusion molding cavity formed on at
least one of a bottom surface of the molding hole of the die and a
tip end surface of the punch, wherein a base plate is molded by a
base plate molding portion formed between the tip end surface of
the punch and the bottom surface of the molding hole, and wherein a
burr is formed by a burr molding portion formed between a tip end
portion outer peripheral side surface of the punch and the inner
peripheral side surface of the molding hole.
8. A production method of a forged product for producing a forged
product in which a protrusion is formed on a base plate,
comprising: a step of setting a forging material in a molding hole
of a die formed by an inclined surface in which an inner peripheral
side surface of the molding hole is inclined with respect to an
axis and approaches the axis towards the inner portion of the
molding hole; and a step of pressurizing the forging material by
driving a punch into the molding hole; wherein in the step of
pressurizing the forging material, a protrusion is formed by a
protrusion molding cavity formed on at least one of a bottom
surface of the molding hole of the die and a tip end surface of the
punch, wherein a base plate is molded by a base plate molding
portion formed between a tip end surface of the punch and the
bottom surface of the molding hole, and wherein a burr is formed by
a burr molding portion formed between a tip end portion outer
peripheral side surface of the punch and the inner peripheral side
surface of the molding hole.
Description
TECHNICAL FIELD
[0001] The present invention relates to a forging device, a forging
method, and a production method of a forged product for producing a
forged product in which a plurality of protrusions, such as, e.g.,
fins, is formed on a base plate.
BACKGROUND ART
[0002] In the case of producing a heat sink having a large number
of fins formed on a front surface or a rear surface of a base plate
by die forging, for example, a semi-sealed forging device (dies) as
shown in Patent Document 1 is used.
[0003] A forging device for molding a heat sink is provided with a
die (lower die) and a punch (upper die), and for example, a number
of fin molding cavities for molding fins are formed in the bottom
surface of the molding hole of the die. When a punch is driven into
a molding hole of a die in which a forging material is set, the
forging material is pressurized and plastically flows, so the
metallic material (metal) as a forging material is filled in the
fin molding cavities and fins are molded. Further, the metal is
also filled in the burr molding portion between the molding hole
inner peripheral side surface of the die and the outer peripheral
side surface of the punch, and burrs are molded. Furthermore, a
base plate is molded by the metal present in the base plate molding
portion between the molding hole bottom surface of the die and the
pressing surface of the punch.
PRIOR ART
Patent Document
Patent Document 1: Japanese Unexamined Patent Application
Publication No. 2015-50318
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0004] In the aforementioned conventional forging process, during
the molding process, the metal is split by a split flow forging
effect into a metal flowing inward and a metal flowing outward. The
metal flowing inward flows into the fin molding cavities of the
inner peripheral portion, while the metal flowing outward flows
into the fin molding cavities of the outer peripheral portion and
the burr molding portion. However, as a result of the analysis of
the flow of the metal (metal flow), it was found the fact that at
the initial stage of pressurization, the metal flowing outward will
not be smoothly discharged from the base plate molding portion to
the burr molding portion, which makes it difficult to reduce the
height dimension (thickness) of the base plate molding portion.
Furthermore, at the stage immediately before completion of the
pressurization, the flow amount of the metal decreases and the
amount of the metal to be filled in the fin forming cavities of the
outer peripheral portion becomes insufficient, which may cause a
risk of causing underfill.
[0005] As described above, in the conventional forging process,
there were problems that it was difficult to reduce the thickness
of the base plate, so a lightweight and compact heat sink could not
be produced. Further, the fin height of a heat sink could not be
made uniform due to the underfill, so a high quality forged product
(heat sink) could not be produced.
[0006] Preferred embodiments of the present invention have been
made in view of the above-mentioned and/or other problems in the
related art. The preferred embodiments of the present invention can
significantly improve upon existing methods and/or apparatuses.
[0007] The present invention has been made in view of the
aforementioned problems, and aims to provide a forging device, a
forging method, and a production method of a forged product,
capable of producing a forged product excellent in dimensional
accuracy of a protrusion height, such as, e.g., a fin height, and
also capable of making the base plate thin to reduce in size and
weight.
[0008] The other purposes and advantages of the present invention
will be made apparent from the following preferred embodiments.
Means for Solving the Problems
[0009] In order to solve the aforementioned problems, the present
invention provides the following means.
[0010] [1] A forging device for producing a forged product in which
a protrusion is formed on a base plate, comprising:
[0011] a die having a molding hole; and
[0012] a punch to be driven into the molding hole,
[0013] wherein a protrusion molding cavity is formed in at least
one of a bottom surface of the molding hole of the die and a tip
end surface of the punch,
[0014] wherein a base plate molding portion is formed between the
tip end surface of the punch and the bottom surface of the molding
hole,
[0015] wherein a burr molding portion is formed between a tip end
portion outer peripheral side surface of the punch and an inner
peripheral side surface of the molding hole, and
[0016] wherein the inner peripheral side surface of the molding
hole is formed by an inclined surface which is inclined with
respect to an axis and approaches the axis toward a pressing
direction of the punch.
[0017] [2] The forging device as recited in the aforementioned Item
[1], wherein a chamfered portion is formed at an internal corner
portion between the inner peripheral side surface and the bottom
surface of the molding hole.
[0018] [3] The forging device as recited in the aforementioned Item
[1] or [2],
[0019] wherein the tip end portion outer peripheral side surface of
the punch is formed by an inclined surface which is inclined with
respect to the axis and approaches the axis toward the pressing
direction of the punch, and
[0020] wherein an inclination angle of the end portion outer
peripheral side surface of the punch with respect to the axis is
formed to be equal to or less than an inclination angle of the
inner peripheral side surface of the molding hole with respect to
the axis.
[0021] [4] The forging device as recited in any one of the
aforementioned Items [1] to [3],
[0022] wherein a chamfered portion is formed at an external corner
portion between the tip end portion outer peripheral side surface
and the tip end surface of the punch.
[0023] [5] The forging device as recited in any one of the
aforementioned Items [1] to [4],
[0024] wherein an external corner portion between the tip end
portion outer peripheral side surface and the tip end surface of
the punch is arranged at a position closer to the axis than the
internal corner portion between the inner peripheral side surface
and the bottom surface of the molding hole.
[0025] [6] The forging device as recited in any one of the
aforementioned Items [1] to [5],
[0026] wherein the protrusion molding cavity is constituted by a
fin molding cavity for molding a fin of a heat sink.
[0027] [7] A forging method for producing a forged product in which
a protrusion is formed on a base plate, comprising:
[0028] a step of setting a forging material in a molding hole of a
die formed by an inclined surface in which an inner peripheral side
surface of a molding hole is inclined with respect to an axis and
approaches the axis toward an inner portion of the molding hole;
and
[0029] a step of pressurizing the forging material by driving a
punch into the molding hole;
[0030] wherein in the step of pressurizing the forging material, a
protrusion is formed by a protrusion molding cavity formed on at
least one of a bottom surface of the molding hole of the die and a
tip end surface of the punch,
[0031] wherein a base plate is molded by a base plate molding
portion formed between the tip end surface of the punch and the
bottom surface of the molding hole, and
[0032] wherein a burr is formed by a burr molding portion formed
between a tip end portion outer peripheral side surface of the
punch and the inner peripheral side surface of the molding
hole.
[0033] [8] A production method of a forged product for producing a
forged product in which a protrusion is formed on a base plate,
comprising:
[0034] a step of setting a forging material in a molding hole of a
die formed by an inclined surface in which an inner peripheral side
surface of the molding hole is inclined with respect to an axis and
approaches the axis towards the inner portion of the molding hole;
and
[0035] a step of pressurizing the forging material by driving a
punch into the molding hole;
[0036] wherein in the step of pressurizing the forging material, a
protrusion is formed by a protrusion molding cavity formed on at
least one of a bottom surface of the molding hole of the die and a
tip end surface of the punch,
[0037] wherein a base plate is molded by a base plate molding
portion formed between a tip end surface of the punch and the
bottom surface of the molding hole, and
[0038] wherein a burr is formed by a burr molding portion formed
between a tip end portion outer peripheral side surface of the
punch and the inner peripheral side surface of the molding
hole.
Effects of the Invention
[0039] According to the forging device of the invention recited in
the aforementioned Item [1], the molding hole inner peripheral side
surface of the die is formed in an inclined surface that approaches
the axis toward the pressing direction of the punch. Therefore, as
the punch is moved downward in accordance with the progress of the
molding, the width of the burr molding portion inlet on the way
from the base plate molding portion to the burr molding portion
gradually narrows. Therefore, at the initial stage of
pressurization, since the width of the burr molding portion inlet
is wide, the metal flowing outward due to the split flow forging
effect preferentially flows to the burr molding portion, so that
the vertical dimension (thickness) of the base plate molding
portion can be formed as thin as desired. Further, at the stage of
the pressurization end, the width of the burr molding portion inlet
becomes narrow and therefore the flow of the metal to the burr
molding portion is suppressed. As a result, the metal is fully
filled in all of the protrusion molding cavities of the outer
peripheral portion. Thus, it is possible to effectively prevent
occurrence of underfill. In this way, the base plate of the forged
product can be made thin, and the forged product can be reduced in
weight and size. Further, the height accuracy of the protrusion can
be improved, so a high quality forged product can be produced.
[0040] Since the molding hole inner peripheral surface is formed in
the inclined surface, the releasability when discharging the forged
roughly shaped material from the molding hole can be improved,
enabling a smooth forging process operation, which in turn can
improve the production efficiency.
[0041] According to the forging device of the invention recited in
the aforementioned Item [2], since the chamfered portion is formed
at the internal corner portion of the molding hole in the die, it
is possible to avoid concentration of the stress on the internal
corner portion of the die at the time of molding. Thus, occurrence
of cracks, etc., of the internal corner portion can be effectively
prevented, which can improve the die life. This in turn can improve
the durability. Further, during the molding, the metal from the
base plate molding portion to the burr molding portion can flow
smoothly, so that the punch load can be reduced correspondingly,
and therefore the device itself can be reduced in size.
[0042] According to the forging device of the invention recited in
the aforementioned Item [3], since the tip end portion outer
peripheral side surface of the punch is formed in an inclined
surface that approaches the axis toward the pressing direction, it
is possible to improve the releasability at the time of separating
the punch from the forged roughly shaped material. Thus, the
forging process operation can be carried out more smoothly, so that
the production efficiency can be further improved.
[0043] According to the forging device of the invention recited in
the aforementioned Item [4], since the chamfered portion is formed
at the external corner portion of the punch, it is possible to
avoid concentration of the stress during molding on the external
corner portion of the punch. Thus, occurrence of cracks, etc., of
the external corner portion can be prevented effectively, which can
improve the die life. This in turn can further improve the
durability. Further, during the molding, the metal can more
smoothly flow from the base plate molding portion to the burr
molding portion, so that the punch load can be reduced
correspondingly, and the device itself can be more assuredly
reduced in size.
[0044] According to the forging device of the invention recited in
the aforementioned Item [5], since the external corner portion of
the punch is arranged inner than the internal corner portion of the
molding hole, it is possible to more assuredly prevent the external
corner portion of the punch from coming into contact with the inner
peripheral side surface of the molding hole, which in turn can more
assuredly prevent breakage, etc., of the due to the contact.
[0045] According to the forging device of the invention recited in
the aforementioned Item [6], it is possible to produce a heat sink
in which a fin is formed on the base plate.
[0046] According to the forging method of the invention recited in
the aforementioned Item [7], in the same manner as described above,
it is possible to produce a high quality forged product reduced in
weight and size and excellent in height accuracy of the
protrusion.
[0047] According to the production method of a forged product of
the invention recited in the aforementioned Item [8], in the same
manner as described above, it is possible to produce a high quality
forged product reduced in weight and size and excellent in height
accuracy of the protrusion.
BRIEF DESCRIPTION OF THE DRAWINGS
[0048] FIG. 1A is a cross-sectional view showing a state
immediately before initiation of molding in a forging device
according to a first embodiment of the present invention.
[0049] FIG. 1B is a cross-sectional view showing a state
immediately after initiation of pressurization in a forging device
according to the first embodiment.
[0050] FIG. 1C is a cross-sectional view showing a state
immediately before completion of pressurization in the forging
device of the first embodiment.
[0051] FIG. 1D is a cross-sectional view showing a state
immediately after initiation of punch rising in the forging device
of the first embodiment.
[0052] FIG. 1E is a cross-sectional view showing a state
immediately after discharge initiation of a forged roughly shaped
material in the first embodiment forging device.
[0053] FIG. 2 is a perspective view showing a heat sink produced
based on a forging device of the first embodiment.
[0054] FIG. 3A is a cross-sectional view showing a state
immediately before initiation of molding in a forging device
according to a second embodiment of the present invention.
[0055] FIG. 3B is a cross-sectional view showing a state
immediately before completion of pressurization in the forging
device of the second embodiment.
[0056] FIG. 4A is a cross-sectional view showing a state
immediately before completion of pressurization in a forging device
according to a third embodiment of the present invention.
[0057] FIG. 4B is a cross-sectional view showing a state
immediately after initiation of punch rising in the forging device
of the third embodiment.
[0058] FIG. 5A is a cross-sectional view showing a state
immediately before completion of pressurization in a conventional
forging device.
[0059] FIG. 5B is a cross-sectional view showing a state
immediately after initiation of punch rising in a conventional
embodiment forging device.
[0060] FIG. 5C is a cross-sectional view showing a state
immediately after discharge initiation of a forged roughly shaped
material in a conventional forging device.
EMBODIMENTS FOR CARRYING OUT THE INVENTION
[0061] FIG. 1A to FIG. 1E are cross-sectional views showing one
side half of a die of a forging device according to a first
embodiment of the present invention. In this embodiment, using the
forging device shown in these figures, a forging material W is
die-forged in a semi-sealed manner to form a heat sink as a forged
product.
[0062] FIG. 2 is a perspective view showing an example of a heat
sink 9 produced by the forging device of the embodiment. As shown
in the figure, the heat sink 9 is provided with a rectangular base
plate 91 and a large number of fins (pin fins) 92 integrally formed
on one surface of the base plate 91.
[0063] As shown in FIG. 1A to FIG. 1E, the forging device of this
embodiment is provided with a die (lower die) 1 and a punch (upper
die) 2.
[0064] The die 1 is provided with a molding hole 11 recessed
downward on its upper surface side. On the bottom surface of this
molding hole 11, a large number of fin molding cavities 32 for
forming fins 92 as protrusions are provided.
[0065] Further, the inner peripheral side surface 13 of the die 1
is formed in an inclined surface which is inclined with respect to
the axis X and gradually approaches the axis X toward the pressing
direction (downward direction) by the punch 2, in other words,
toward the inner portion of the molding hole 11. In this
embodiment, as shown in FIG. 1A, the inclination angle .alpha. of
the molding hole inner peripheral side surface 13 with respect to
the axis X is set to 0.1.degree. to 20.degree..
[0066] In this embodiment, although the molding hole inner
peripheral side surface 13 is formed in a straight line in
cross-section, it is not always necessary to form it in a straight
line in cross-section. The molding hole inner peripheral side
surface is not necessarily formed in a straight shape in
cross-section but may be formed in a slightly bent arc shape in
cross-section or a slightly bent polygonal shape in cross-section
or the like. Such cases are also included in the present
invention.
[0067] In this embodiment, the lower end outer peripheral edge
portion of the molding hole inner peripheral side surface 13 of the
die 1, in other words, the entire circumference of the corner
portion between the bottom surface of the molding hole 11 and the
inner peripheral side surface 13, forms an internal corner portion
14.
[0068] The punch 2 is arranged so that the axis thereof coincides
with the axis of the die 1, and is configured to be vertically
movable up and down, so that the tip end portion of the punch 2 is
driven into the molding hole 11 of the die 1 with a predetermined
load.
[0069] In this embodiment, the tip end portion of the punch 2
denotes a portion which is to be accommodated in the molding hole
11 when the punch 2 is driven into the die 1.
[0070] In this embodiment, the tip end surface outer peripheral
edge portion of the punch 2, in other words, the entire
circumference of the corner portion between the tip end surface of
the punch 2 and the outer peripheral side surface 23, forms the
external corner portion 24.
[0071] In the forging device having the configuration of this
embodiment, as shown in FIG. 1B, FIG. 1C, etc., when the punch 2 is
driven into the die 1, between the bottom surface of the molding
hole 11 of the die 1 and the tip end surface (pressurizing surface)
of the punch 2, a base plate molding portion 31 for molding the
base plate 91 of the heat sink 9 is formed, and between the inner
peripheral side surface 13 of the molding hole 11 of the die 1 and
the outer peripheral side surface 23 of the punch 2, a burr molding
portion 33 for molding a burr is formed. This burr molding portion
33 is open to the outside.
[0072] In this embodiment, between the tip end surface outer
peripheral edge portion (external corner portion) 24 and the inner
peripheral side surface 13 of the molding hole 11, a burr molding
portion inlet 34 is formed. As shown in FIG. 1B and FIG. 1C, in
this embodiment, the width T of this burr molding portion inlet 34
corresponds to the horizontal dimension between the external corner
portion 24 of the punch 2 and the molding hole inner peripheral
side surface.
[0073] In the case of performing a forging process using the
forging device having the aforementioned configuration, as shown in
FIG. 1A, a forging material W is put in the molding hole 11 of the
die 1.
[0074] As the forging material W, those made of an aluminum alloy
or a copper alloy are preferably used. In this embodiment, a plate
material is used as a forging material W. For example, this plate
material may be produced by cutting a rolled material by trimming
or machining, or may be produced by cutting a flat bar shaped
extrusion material or cutting a rectangular continuous cast bar.
Needless to say, the forging material W is formed to have a size
and a shape capable of being accommodated in the molding hole 11 of
the die 1.
[0075] The forging material W to be input is subjected to a
lubrication treatment as necessary and heated to about 400.degree.
C. to 600.degree. C., and dies, such as, e.g., the die 1 and the
punch 2, are also subjected to a lubrication treatment as necessary
and heated. Needless to say, in the case of cold forging, the
forging material W and the die are not heated.
[0076] After setting the forging material W in the molding hole 11,
the punch 2 is lowered to press the forging material W. As shown in
FIG. 1B, in the state immediately after initiation of the
pressurization against the forging material W with the punch 2, the
metallic material (metal) constituting the forging material W is
divided into the metal flowing toward the center (radially inward
direction) and the metal flowing toward the outer side (radially
outward direction) by the split flow forging effect. Among them, by
the metal flowing toward the center, the fin molding cavities 32 at
the center portion are filled sufficiently. On the other hand,
since the molding hole inner peripheral side surface 13 is formed
in an inclined surface, at the stage in which the tip end portion
of the punch 2 immediately after initiation of the pressurization
has not been completely driven into the molding hole 11, the width
T of the burr molding portion inlet 34 between the external corner
portion 24 of the punch 2 and the molding hole inner peripheral
side surface 13 is sufficiently wide. For this reason, a large
amount of metal toward the outside smoothly flows toward the burr
molding portion 33, and therefore the metal is efficiently
discharged from the base plate molding portion 31 between the punch
tip end surface and the molding hole bottom surface to the burr
molding portion 33. Thus, the vertical dimension of the base plate
molding portion 31 can be formed sufficiently small.
[0077] In this way, at the initial stage of pressurization, the
metal toward the outside actively flows toward the burr molding
portion 33. Therefore, the filling amount of the metal to the fin
molding cavities 32 on the outer side is smaller than the metal
filling amount of the fin molding cavities 32 at the center
portion.
[0078] However, as the molding progresses, the width T of the burr
molding portion inlet 34 between the external corner portion 24 of
the punch 2 and the molding hole inner peripheral side surface 13
gradually narrows as the punch 2 descends. In the state immediately
before completion of pressurization, as shown in FIG. 1C, the metal
toward the outside is suppressed from flowing into the burr molding
portion 33, which promotes the inflow to the fin molding cavities
32 on the outer side. In this way, the fin molding cavities 32 on
the outer side are also sufficiently filled with the metal, and
therefore all the fin molding cavities 32 in the center and outside
are sufficiently filled with the metal. Thus, a forged roughly
shaped material for a heat sink is molded.
[0079] In the present invention, a back pressure forging in which
the bottom surface portion of the fin molding cavity 32 is
constituted by a movable back pressure pin so that resistance (back
pressure) in the direction opposite to the inflow direction is
imparted to the metal flowing into the fin molding cavity 32 may be
adopted.
[0080] On the other hand, as shown in FIG. 1D, upon completion of
the pressurization by the punch 2 (completion of molding), after
the punch 2 is raised and returned to the initial position, as
shown in FIG. 1E, the forged roughly shaped material is pushed
upward from the molding hole 11 and discharged by knockout pins
(not shown).
[0081] In the forged roughly shaped material molded as described
above, burrs are removed by trim processing. After that, the formed
forged roughly shaped material is subjected to machining and
washing as necessary and finished as a heat sink 9 as a forged
product as shown in FIG. 2.
[0082] As described above, according to the forging device of this
embodiment, since the molding hole inner peripheral side surface 13
of the die 1 is formed in an inclined surface that expands toward
upward, as the punch 2 descends as the forming progresses, the
width T of the burr molding portion inlet 34 on the way from the
base plate molding portion 31 to the burr molding portion 33
gradually narrows. For this reason, at the initial stage of
pressurization, the metal flows preferentially to the fin molding
cavities 32 at the center portion and the burr molding portion 33,
so it is possible to form the vertical dimension (thickness) of the
base plate molding portion 31 as thin as desired. Further, at the
final stage of the molding, the width T of the burr molding portion
inlet 34 narrows, so that the flow of the metal toward the burr
molding portion 33 is suppressed. For this reason, the metal is
sufficiently filled also in the fin molding cavities 32 at the
outer peripheral portion, so that the metal is sufficiently filled
in all of the fin molding cavities 32, which can effectively
prevent occurrence of underfill.
[0083] Accordingly, all fin heights of the heat sink 9 as a forged
product can be precisely matched, and a high quality forged product
can be produced.
[0084] Furthermore, since the thickness of the base plate molding
portion 31 can be made thin, the base plate 91 of the heat sink 9
as a forged product can be formed thin, so that the heat sink 9 can
be reduced in weight and size.
[0085] Further, in this embodiment, since the molding hole inner
peripheral side surface 13 of the die 1 is formed in an inclined
surface, it is possible to reduce the load (forging load) by the
punch 2.
[0086] That is, in a conventional forging device, as shown in FIG.
5A, the inner peripheral side surface 13 of the molding hole 11 of
the die 1 and the outer peripheral side surface 23 of the punch 2
are both formed by vertical planes, and the width of the burr
molding portion 33 constituted by and between these side surfaces
13 and 23 is formed constant regardless of the vertical position.
Therefore, the metal flowing from the base plate molding portion 31
into the burr molding portion 33 is filled into the burr molding
portion 33 while being in surface contact with the molding hole
inner peripheral side surface 13 and the punch outer peripheral
side surface 23. For this reason, the flow resistance of the metal
flowing through the burr molding portion 33 increases, so that it
is necessary to increase the punch load accordingly. As a result,
it is necessary to enlarge the press machine, which may cause an
increased weight of the forging device.
[0087] In contrast, in this embodiment, as shown in FIG. 1C, the
molding hole inner peripheral side surface 13 is formed in an
inclined surface. Therefore, the metal flowing from the base plate
molding portion 31 to the burr molding portion 33 only makes line
contact with the external corner portion 24 of the punch 2 and is
hardly subjected to the surface contact resistance to the molding
hole inner peripheral side surface 13 and the punch outer
peripheral side surface 23. Therefore, the flow resistance of the
metal flowing through the burr molding portion 33 decreases, and
the punch load can be reduced accordingly. As a result, it is
possible to reduce the size and weight of the forging device
itself, and it is possible to produce a large forged product large
in projection area with a small compact machine of a press machine.
Furthermore, since the flow resistance of the metal flowing through
the burr molding portion 33 is small, it is possible to increase
the discharge amount of the metal from the base plate molding
portion 31 to the burr molding portion 33, which in turn can
assuredly reduce the thickness of the base plate molding portion
31. Thus, the thickness of the base plate 91 in the forged product
can be more assuredly formed to be thin.
[0088] As shown in FIG. 5A, in a conventional forging device, the
contact area and the contact pressure between the burr W3 of the
forged roughly shaped material and the punch outer peripheral side
surface 23 are large. As shown in FIG. 5B, when raising the punch 2
after pressurization, the releasability of the punch 2 to the
forged roughly shaped material (burr W3) is bad, which prevents the
smooth forging process operation. Therefore, there is a possibility
of causing deterioration of the productivity.
[0089] In contrast, in this embodiment, as shown in FIG. 1C, the
contact area and the contact pressure between the burr W3 of the
forged roughly shaped material and the punch outer peripheral side
surface 23 are smaller than those of the conventional forging
device shown in FIG. 5A. Therefore, as shown in FIG. 1D, when
raising the punch 2 after pressurization, the releasability of the
punch 2 with respect to the forged roughly shaped material (burr
W3) is good, enabling the smooth forging process operation, which
can improve the productivity.
[0090] Further, as shown in FIG. 5C, in the conventional forging
device, the molding hole inner peripheral side surface 13 is formed
vertically. For this reason, it is difficult to discharge the
forged roughly shaped material from the molding hole 11 due to the
influence of the contact resistance of the burr W3 to the molding
hole inner peripheral side surface 13 at the time of pushing out
the forged roughly shaped material from the molding hole 11 after
molding. In some cases, harmful deformation such as bending
deformation may occur in the forged roughly shaped material. From
this point as well, the forging process operation cannot be
performed smoothly, which may sometimes cause deterioration of the
productivity.
[0091] On the other hand, as shown in FIG. 1E, in the forging
device of this embodiment, the molding hole inner peripheral side
surface 13 is formed in an inclined surface. For this reason, when
the forged roughly shaped material is slightly raised after
molding, the contact resistance of the burr W3 to the molding hole
inner peripheral side surface 13 disappears. Therefore, the forged
roughly shaped material can be discharged from the molding hole 11
without difficulty, which can assuredly prevent occurrence of
harmful bending deformation, etc., and also can perform the forging
process more smoothly. Thus, the productivity can be further
improved.
Examples and Comparative Examples
[0092] A forging device similar to the forging device of the first
embodiment shown in FIG. 1A to FIG. 1E was prepared. At this time,
a die 1 and a punch 2 were prepared under the conditions of
producing a heat sink in which columnar pin fins 92 each having a
pin diameter .phi. of 2.2 mm and a height of 10 mm were formed in a
staggered arrangement manner on one surface side of the base plate
91, a distance (distance between pin outer diameters) between
adjacent pin fins 92 was 0.9 mm, the number of pins was
13.times.40, a total of 520.
[0093] In the forging device, a die 1 was prepared in which the
inclination angle .alpha. of the molding hole inner peripheral side
surface 13 was 10.degree.. Note that the tip end portion outer
peripheral side surface 23 of the punch 2 was a vertical plane with
an inclination angle of 0.degree..
[0094] As a forging material W, a 1,000 series aluminum alloy was
prepared. As this material W, a material formed by cutting an
extrusion material (flat bar) with a width of 50 mm.times.a
thickness of 4 mm was cut into 80 mm was prepared. The material W
has been adjusted to fit the molding hole 11 of the die 1.
[0095] Then, the dies, such as the die 1 and the punch 2, of the
forging device was heated to 200.degree. C. or higher, lubricant
was directly sprayed onto the dies immediately before forging
process, and then the forging material W was put in a molding hole
11 of the die 1. Note that the forging material W which was
pre-heated to 500.degree. C. without performing a lubrication
treatment was used.
[0096] After setting the forging material W in the forging device
as described above, a forging process was performed in the same
manner as in the first embodiment to produce the forged product
(heat sink) of an example. In the obtained forged product (heat
sink), the thickness of the base plate 91 was made as thin as about
0.3 mm. Furthermore, the variation in the pin height could be
controlled to 0.5 mm or less, and the pin heights could be matched
without problems. In addition, defects, such as bent deformation
which is harmful to the forged product, were not particularly
recognized.
[0097] On the other hand, except that a forging device similar to
the conventional forging device shown in FIG. 5A to FIG. 5C was
used, that is, except that a forging device in which the molding
hole inner peripheral side surface 13 of the die 1 is a vertical
plane of an inclination angle 0.degree. was used, a forged product
(heat sink) was produced in the same manner as in the
aforementioned example. In the obtained forged product, the
thickness of the base plate 91 could not be controlled to 1 mm or
less, and the variation in the pin height was also 0.5 mm or more,
so that the pin heights could not be aligned. Further, at the time
of taking out the forged roughly shaped material from the die 1,
some forged roughly shaped materials had harmful bending
deformation.
[0098] As will be apparent from the aforementioned examples and
comparative examples, according to the forging device of the
present invention, the thickness of the base plate 91 could be made
thin, and a high quality heat sink 9 with matched pin heights could
be manufactured.
Second Embodiment
[0099] FIG. 3A and FIG. 3B are cross-sectional views each showing a
forging device according to a second embodiment of the present
invention. As shown in both figures, in this forging device of the
second embodiment, a chamfered portion 15 is formed at the internal
corner portion 14 of the lower end of the molding hole in the die
1. In this embodiment, the chamfered portion 15 is constituted by
an R-plane. By this chamfered portion 15, the portion from the
inner peripheral side surface 13 to the bottom surface of the
molding hole 11 is formed as a smooth continuous surface.
[0100] Further, a chamfered portion 25 is formed at the external
corner portion 24 of the tip end surface outer peripheral edge
portion of the punch 2. In this embodiment, the chamfered portion
25 is constituted by an R-plane. By this chamfered portion 25, the
portion from the outer peripheral side surface 23 of the punch 2 to
the tip end surface is formed into a smooth continuous surface.
[0101] In this forging device of this second embodiment, since the
other configuration is substantially the same as that of the
forging device of the first embodiment, the same or equivalent
parts are allotted by the same reference numerals, and the
redundant description will be omitted.
[0102] Also in this forging device of the second embodiment, the
same effect as that of the forging device of the first embodiment
can be obtained.
[0103] Furthermore, in the second forging device, the chamfered
portions 15 and 25 are formed at the internal corner portion 14 of
the molding hole lower end outer peripheral edge portion of the die
1 and the external corner portion 24 of the tip end surface outer
peripheral edge portion of the punch 2, respectively. Therefore,
the internal corner portion 14 and the external corner portion 24
each are not formed in a sharp edge shape, so the durability can be
improved. That is, if the internal corner portion 14 of the die 1
and the external corner portion 24 of the punch 2 each are formed
into a sharp edge, stress concentrates on the internal corner
portion 14 and the external corner portion 24 when the punch 2 is
driven. In such a case, cracks tend to occur in the internal corner
portion 14 of the die 1 and the external corner portion 24 of the
punch 2, so that the die life becomes short and the durability may
deteriorate.
[0104] In view of the above, in the second embodiment, the
chamfered portions 15 and 25 are formed in the internal corner
portion 14 of the die 1 and the external corner portion 24 of the
punch 2, respectively, the internal corner portion 14 and the
external corner portion 24 each have a smooth shape, so it is
possible to prevent local concentration of the stress on the
internal corner portion 14 and the external corner portion 24 at
the time of driving the punch. For this reason, it is possible to
effectively prevent occurrence of cracks in the internal corner
portion 14 of the die 1, the external corner portion 24 of the
punch 2, etc., so that the die life can be extended and the
durability can be improved.
[0105] Furthermore, in this forging device of the second
embodiment, since the chamfered portion 25 is formed at the
external corner portion 24 of the punch 2, it is possible to
assuredly prevent such a trouble that the external corner portion
24 of the punch 2 comes into contact with the inner peripheral side
surface 13 of the molding hole 11 of the die 1, which can assuredly
prevent damage of the due to the contact.
[0106] Furthermore, in this forging device of the second
embodiment, since the chamfered portions 15 and 25 are each formed
in the internal corner portion 14 of the molding hole 11 and the
external corner portion 24 of the punch 2, the burr molding portion
inflow passage from the base plate molding portion 31 to the burr
molding portion inlet 34 is formed by a gently curved circular arc
flow passage rather than a bent flow passage that rapidly changes
in direction. For this reason, the flow of the metal from the base
plate molding portion 31 to the burr molding portion 33 can be
performed smoothly during the molding, which can further reduce the
punch load. This in turn can further miniaturize the forging
device.
[0107] Note that in this second embodiment, the chamfered portions
15 and 25 of the internal corner portion 14 of the molding hole 11
and the external corner portion 24 of the punch 2 are formed by an
R-plane, but the present invention is not limited to this. In the
present invention, the internal corner portion 14 and the external
corner portion 24 may be each formed by a C-plane or multiple
planes.
Third Embodiment
[0108] FIG. 4A and FIG. 4B are cross-sectional views each showing a
forging device according to a third embodiment of the present
invention. As shown in these figures, in the forging device of this
third embodiment, the tip end portion outer peripheral side surface
23 of the punch 2 is formed in an inclined surface which is
inclined with respect to the axis X and gradually approaches the
axis X toward the pressing direction (downward direction). In this
embodiment, the inclination angle .beta. of the punch outer
peripheral side surface 23 with respect to the axis X is set to
0.1.degree. to 20.degree.. The inclination angle .beta. of the
punch outer peripheral surface 23 is equal to or smaller than the
inclination angle .alpha. of the molding hole inner peripheral side
surface 13 shown in FIG. 1A.
[0109] In this embodiment, although the punch outer peripheral side
surface 23 is formed in a straight line in cross-section, it is not
always necessary to form it in a straight line in cross-section.
The punch outer peripheral side surface 23 is not necessarily
formed in a straight shape in cross-section, but may be formed in a
slightly bent arc shape in cross-section or a slightly bent
polygonal shape in cross-section or the like. Such cases are also
included in the present invention.
[0110] Further, the position of the tip end surface outer
peripheral edge portion (external corner portion) 24 of the punch 2
is arranged at a position closer to the axis X than the position of
the molding hole lower end inner peripheral edge portion (internal
corner portion) 14 of the die 1.
[0111] In this third forging device, since the other configuration
is substantially the same as that of the forging device of the
first embodiment, the same or equivalent parts are allotted by the
same reference numerals, and the redundant description will be
omitted.
[0112] The third embodiment of the forging device can also obtain
the same effects as those of the aforementioned first forging
device.
[0113] Furthermore, in the forging device of the third embodiment,
since the tip end portion outer peripheral side surface 23 of the
punch 2 is formed in the inclined surface, as shown in FIG. 4B, at
the time when the punch 2 is raised slightly after pressurization,
the contact of the punch 2 to the burr W3 is released and the whole
area is separated. For this reason, at the time of rising the punch
2, the punch 2 can be separated without difficulty from the forged
roughly shaped material, enabling a more smooth forging process
operation, which further can improve the production efficiency.
[0114] Furthermore, in the forging device of this third embodiment,
since the external corner portion 24 of the punch 2 is arranged
inner than the internal corner portion 14 of the molding hole 11,
it is possible to more assuredly prevent the external corner
portion 24 of the punch 2 from coming into contact with the inner
peripheral side surface of the molding hole 11 of the die 1, which
in turn can more assuredly prevent breakage of the due to the
contact.
[0115] In each of the above-described embodiments, the case in
which the fin molding cavities 32 are formed on the die 1 side has
been described as an example, but the present invention is not
limited thereto. In the present invention, fin molding cavities may
be formed on the punch side, or a heat sink (forged product) in
which fins are formed on both surfaces of the base plate may be
formed by forming fin molding cavities on both the die side and the
punch side.
[0116] Further, in the above-described embodiments, the case in
which the heat sink having pin fins formed on the base plate is
described as an example, but the present invention is not limited
thereto. The present invention can also be applied to the case of
forming a heat sink having plate fins formed on one or both sides
of the heat sink.
[0117] Further, in the above-described embodiments, the case in
which the heat sink is formed by the present invention has been
described as an example, but the present invention is not limited
to such a heat sink. The present invention can be adopted in the
case of producing a forged product in which a plurality of
protrusions is formed on at least one surface of a base plate.
[0118] Further, in the above-described embodiments, the position of
the external corner portion 24 of the punch 2 from the axis X is
set to be equal to or inner than the position of the internal
corner portion 14 of the die molding hole 11 from the axis X, in
other words, the horizontal distance of the external corner portion
24 of the punch 2 from the axis X is set to be equal to or shorter
than the horizontal distance of the internal corner portion 14 of
the die molding hole 11 from the axis X. However, the present
invention is not limited to it, and the position of the punch
external corner portion 24 may be arranged outside the die molding
hole internal corner portion 14.
[0119] While illustrative embodiments of the invention have been
described herein, the present invention is not limited to the
various preferred embodiments described herein, but includes any
and all embodiments having equivalent elements, modifications,
omissions, combinations (e.g., of aspects across various
embodiments), adaptations and/or alterations as would be
appreciated by those in the art based on the present disclosure.
Limitations in the claims are to be interpreted broadly based on
the language employed in the claims and not limited to examples
described in the present specification or during the prosecution of
the application, which examples are to be construed as
non-exclusive. A number of illustrative embodiments are described
herein with the understanding that the present disclosure is to be
considered as providing examples of the principles of the invention
and such examples are not intended to limit the invention to
preferred embodiments described herein and/or illustrated
herein.
[0120] The present application claims priority to Japanese Patent
Application No. 2016-111479 filed on Jun. 3, 2016, the entire
disclosure of which is incorporated herein by reference in its
entirety.
[0121] While illustrative embodiments of the invention have been
described herein, the present invention is not limited to the
various preferred embodiments described herein, but includes any
and all embodiments having equivalent elements, modifications,
omissions, combinations (e.g., of aspects across various
embodiments), adaptations and/or alterations as would be
appreciated by those in the art based on the present disclosure.
Limitations in the claims are to be interpreted broadly based on
the language employed in the claims and not limited to examples
described in the present specification or during the prosecution of
the application, which examples are to be construed as
non-exclusive. For example, in the present disclosure, the term
"preferably" is non-exclusive and means "preferably, but not
limited to." In this disclosure and during the prosecution of this
application, means-plus-function or step-plus-function limitations
will only be employed where for a specific claim limitation all of
the following conditions are present in that limitation: a) "means
for" or "step for" is expressly recited; b) a corresponding
function is expressly recited; and c) structure, material or acts
that support that structure are not recited. In this disclosure and
during the prosecution of this application, the terminology
"present invention" or "invention" may be used as a reference to
one or more aspect within the present disclosure. The language
present invention or invention should not be improperly interpreted
as an identification of criticality, should not be improperly
interpreted as applying across all aspects or embodiments (i.e., it
should be understood that the present invention has a number of
aspects and embodiments), and should not be improperly interpreted
as limiting the scope of the application or claims. In this
disclosure and during the prosecution of this application, the
terminology "embodiment" can be used to describe any aspect,
feature, process or step, any combination thereof, and/or any
portion thereof, etc. In some examples, various embodiments may
include overlapping features. In some examples, various embodiments
may include overlapping features. In this disclosure and during the
prosecution of this case, the following abbreviated terminology may
be employed: "e.g." which means "for example;" and "NB" which means
"note well."
INDUSTRIAL APPLICABILITY
[0122] The forging device of the present invention can be suitably
applied in manufacturing a forged product, such as, e.g., a heat
sink in which a large number of fins are formed on a base
plate.
DESCRIPTION OF REFERENCE SYMBOLS
[0123] 1: die (lower die) [0124] 11: molding hole [0125] 13: inner
peripheral side surface [0126] 14: internal corner portion [0127]
15: chamfered portion [0128] 2: punch (upper die) [0129] 23: outer
peripheral side surface [0130] 24: external corner portion [0131]
25: chamfered portion [0132] 31: base plate molding portion [0133]
32: fin molding cavity (protrusion molding cavity) [0134] 33: burr
molding portion [0135] 9: heat sink (forged product) [0136] 91:
base plate [0137] 92: fin (pin fin) [0138] W: forging material
[0139] W3: burr [0140] X: axis [0141] .alpha.: inclination angle of
the molding hole inner peripheral side surface [0142] .beta.:
inclination angle of the punch tip end portion outer peripheral
side surface
* * * * *