U.S. patent application number 09/740874 was filed with the patent office on 2001-06-07 for mold device, electronic apparatus, and electronic apparatus manufacturing method.
This patent application is currently assigned to Kabushiki Kaisha Toshiba. Invention is credited to Hosoi, Takashi, Kiuchi, Mikio, Ono, Yasuo, Takaki, Nobuyuki.
Application Number | 20010002618 09/740874 |
Document ID | / |
Family ID | 15988087 |
Filed Date | 2001-06-07 |
United States Patent
Application |
20010002618 |
Kind Code |
A1 |
Hosoi, Takashi ; et
al. |
June 7, 2001 |
Mold device, electronic apparatus, and electronic apparatus
manufacturing method
Abstract
In a mold device comprising pin members provided projecting from
an upper mold or a lower mold in order to form an electronic
apparatus frame of a metallic material having pores arranged at
given pitches, the pin members are arranged so that a center line
connecting the adjacent pin members is not perpendicular to the
direction of introduction of a molten metal into a cavity of the
mold device.
Inventors: |
Hosoi, Takashi; (Tokyo,
JP) ; Takaki, Nobuyuki; (Tokyo, JP) ; Ono,
Yasuo; (Yokohama-shi, JP) ; Kiuchi, Mikio;
(Kawagoe-shi, JP) |
Correspondence
Address: |
Finnegan, Henderson, Farabow,
Garrett & Dunner, L.L.P.
1300 I Street, N.W.
Washington
DC
20005-3315
US
|
Assignee: |
Kabushiki Kaisha Toshiba
|
Family ID: |
15988087 |
Appl. No.: |
09/740874 |
Filed: |
December 21, 2000 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
09740874 |
Dec 21, 2000 |
|
|
|
PCT/JP99/03238 |
Jun 17, 1999 |
|
|
|
Current U.S.
Class: |
164/113 ;
164/302 |
Current CPC
Class: |
B22C 9/06 20130101 |
Class at
Publication: |
164/113 ;
164/302 |
International
Class: |
B22D 027/09; B22D
025/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 22, 1998 |
JP |
10-174978 |
Claims
What is claimed is:
1. In a mold device comprising pin members provided projecting from
a first mold or a second mold in order to form an electronic
apparatus frame of a metallic material having pores arranged at
given pitches, said pin members being arranged so that a center
line connecting the closest adjacent pin members is not
perpendicular to the direction of introduction of a molten metal
into a cavity of the mold device.
2. In a mold device comprising pin members provided projecting from
a first mold or a second mold in order to form an electronic
apparatus frame of a metallic material having pores arranged at
given pitches, said pin members being arranged so that one row of
pin members, out of each two adjacent rows of pin members, is
shifted substantially for half the pitch in the direction thereof
with respect to the other row of pin members.
3. In a mold device comprising pin members provided projecting from
a first mold or a second mold in order to form an electronic
apparatus frame of a metallic material having pores arranged at
given pitches, said pin members being arranged in a zigzag
array.
4. In a mold device comprising pin members provided projecting from
a first mold or a second mold in order to form an electronic
apparatus frame of a metallic material having pores arranged at
given pitches, said pin members being arranged in zigzag with
respect to the direction of introduction of a molten metal.
5. An electronic apparatus manufacturing method for molding an
electronic apparatus including a frame of a metallic material
having pores arranged at given pitches, by means of a mold device,
comprising: a flowing process for diffusing a molten metal
throughout the interior of said mold device; and a solidifying
process for solidifying the molten metal introduced into the mold
device in said flowing process, thereby forming the frame, said
mold device being the mold device according to any one of claims 1
to 4.
6. In an electronic apparatus including an electronic apparatus
frame of a metallic material having pores arranged at given
pitches, said electronic apparatus frame being formed by
casting.
7. An electronic apparatus according to claim 6, wherein said
metallic material is magnesium.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation of application No. PCT/JP99/03238,
filed Jun. 17, 1999.
[0002] This application is based upon and claims the benefit of
priority from the prior Japanese Patent Application No. 10-174978,
filed Jun. 22, 1998, the entire contents of which are incorporated
herein by reference.
BACKGROUND OF THE INVENTION
[0003] This invention relates to a configuration of a light metal
frame of an electronic apparatus, such as a personal computer, a
manufacturing method for manufacturing the electronic apparatus
frame, and a mold device.
[0004] Recently, magnesium alloys have been mainly used as the
material of an electronic apparatus frame of a light metal. These
alloys are molded by die-casting or thixotropy. These molding
methods use different equipment mechanisms. In either method,
however, an alloy melted at 580.degree. C. to 750.degree. C. is
injected into a mold of about 100.degree. C. to 350.degree. C. and
molded.
[0005] FIG. 6 shows a configuration of a conventional electronic
apparatus frame. In this electronic apparatus frame, a molten metal
is poured through a sprue 2, for use as a molten metal inlet
portion (a portion corresponding to the shape of the electronic
apparatus frame just molded will be described with reference to
this drawing), and the molten metal is introduced into a desired
mold through a runner 3. The introduced molten metal diffuses
throughout a cavity 4 and finally reaches air vents 5. Further, a
molten metal reservoir 6 is coupled to the air vents 5. When the
molten metal is introduced through the sprue 2, therefore, air can
be discharged to the outside through the air vents 5. Thereupon,
the frame can be formed without containing any voids therein.
[0006] This electronic apparatus frame sometimes may be provided
with a large number of pores 7 that are arranged at given pitches
and serve to discharge heat to the outside or serve as a speaker
for external sounding.
[0007] Generally, in this case, the pores 7 are arrayed like a
lattice, as shown in FIGS. 6 and 7, in order to keep spaces between
the pores uniform.
[0008] Conventionally, in order to form the pores 7 in this array,
a molded piece molded by means of a mold device 1 is stamped out,
in some cases. Alternatively, pin members 8 in a latticelike array
are previously formed projecting from the inside of the cavity 4 of
the mold device 1, as shown in FIG. 7. In this case, the molten
metal is introduced into the cavity 4 to be solidified therein. The
pores 7 in this latticelike array are formed by doing this.
[0009] In general, the pores 7 are arranged at narrow pitches in
order to prevent foreign matter from getting into the frame.
Therefore, postforming the molded piece with the narrow pitches
after the removal from the mold device 1 in the aforesaid manner
requires labor and cost depending on the number of pores.
[0010] Thus, the pin members 8 are previously arranged at narrow
pitches in the mold device 1. Since the molten metal introduced
into the mold is rapidly cooled and solidified when it touches the
inner wall surface of the cavity 4, however, its fluidity is not
satisfactory in the case where a large number of pin members 8 are
arranged at narrow pitches, in particular.
[0011] More specifically, the molten metal may be solidified as it
passes straight between the rows of the pin members 8, as indicated
by arrows in FIG. 7, possibly failing to get into gaps 9 between
the pin members 8 that constitute the rows.
[0012] Thus, the molten metal fails to penetrate into the regions
between the pin members 8 and forms unfilled portions, so that the
pores 7 cannot be formed in the given array, and substantial
unfilled portions are formed inevitably.
BRIEF SUMMARY OF THE INVENTION
[0013] This invention has been contrived in consideration of these
circumstances, and its object is to provide a mold device, having
an array of pin members capable of improving the fluidity of a
molten metal therein, and a manufacturing method for an electronic
apparatus frame based on this array of pin members.
[0014] According to a preferred embodiment, a mold device of this
invention is a mold device comprising pin members provided
projecting from a first mold or a second mold in order to form an
electronic apparatus frame of a metallic material having pores
arranged at given pitches, the pin members being arranged so that a
center line connecting the closest adjacent pin members is not
perpendicular to the direction of introduction of a molten metal
into a cavity of the mold device.
[0015] Further, an electronic apparatus manufacturing method of
this invention is an electronic apparatus manufacturing method for
molding an electronic apparatus including a frame of a metallic
material having pores arranged at given pitches, by means of a mold
device, comprising a flowing process for diffusing a molten metal
throughout the interior of the mold device, and a solidifying
process for solidifying the molten metal introduced into the mold
device in the flowing process, thereby forming the frame, the mold
device being the aforementioned mold device.
[0016] Additional objects and advantages of the invention will be
set forth in the description which follows, and in part will be
obvious from the description, or may be learned by practice of the
invention. The objects and advantages of the invention may be
realized and obtained by means of the instrumentalities and
combinations particularly pointed out hereinafter.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0017] The accompanying drawings, which are incorporated in and
constitute a part of the specification, illustrate presently
preferred embodiments of the invention, and together with the
general description given above and the detailed description of the
preferred embodiments given below, serve to explain the principles
of the invention.
[0018] FIG. 1 is a perspective view showing the shape of a prior
art electronic apparatus frame;
[0019] FIG. 2 is a view showing a prior art array of pin members
and flows of a molten metal;
[0020] FIG. 3 is a perspective view showing a configuration of a
portable computer as an electronic apparatus according to one
embodiment of this embodiment;
[0021] FIG. 4 is a view showing a state of a pin member array in a
mold device of the same embodiment and illustrating the way rows of
pin members are shifted for half the pitch in the direction
perpendicular to the direction of introduction of a molten
metal;
[0022] FIG. 5 is a view showing a state of a pin member array in
the mold device of the same embodiment and illustrating the way
rows of pin members are shifted for half the pitch in the direction
parallel to the direction of introduction of the molten metal;
[0023] FIG. 6 is a view showing a state of a pin member array in a
zigzag form;
[0024] FIG. 7 is a side sectional view showing a configuration of a
mold device of the same embodiment;
[0025] FIG. 8 is a perspective view showing a configuration of an
electronic apparatus frame of the same embodiment; and
[0026] FIG. 9 is a view showing a state in which the direction of
introduction of the molten metal is inclined at a given angle to a
latticelike array of pin members according to a modification of
this invention.
DETAILED DESCRIPTION OF THE INVENTION
[0027] One embodiment of the present invention will now be
described with reference to FIGS. 3 to 8.
[0028] FIG. 3 is an external view showing the shape of a portable
computer 10 such as a note-type personal computer. In this drawing,
the portable computer 10 comprises a computer body 11 and a display
unit 12 that is rockably supported on the computer body 11. The
computer body 11 is provided with a frame 13, and this frame 13 is
designed so that a lower frame 14 and an upper frame 15 are
suitably joined by means of, for example, screws or the like.
However, the lower frame 14 and the upper frame 15 may be joined by
means of any other arrangement than this.
[0029] In the description to follow, the frame that is applied to
the portable computer 10 or some other electronic apparatus will be
described as an electronic apparatus frame 20. The following
description is based on FIGS. 4 to 8.
[0030] The electronic apparatus frame 20 of the light metal
personal computer, formed of a magnesium alloy, for example, is
formed having a large number of pores 21 arranged at short pitches.
The pores 21 serve to cool the inside of the personal computer or
serve as a speaker for external sounding.
[0031] These numerous pores 21 can be formed by introducing a
molten metal into a mold device 30, which will be described
below.
[0032] The mold device 30 includes an upper mold 31 as a first mold
and a lower mold 32 as a second mold, which engage each other to
form the mold device 30. The mold device 30 is provided with a
sprue 33, for use as a molten metal inlet, and a runner 34 for
guiding the molten metal in introduction into the mold device 30
and in uniform diffusion. The molten metal guided by means of the
runner 34 is introduced into a cavity 35 of the mold device 30.
[0033] Although the molten metal is a molten magnesium alloy, it
may be replaced with any other alloy, such as an aluminum
alloy.
[0034] Pin members 36 are provided in those portions of the cavity
35 which correspond to the pores 21 of the electronic apparatus
frame 20 in order to form the pores 21 in the electronic apparatus
frame 20. The pin members 36 are formed having the following array
in the cavity 35 of the mold device 30, compared with the
conventional latticelike array.
[0035] If the distance between each two adjacent ones of the pin
members 36 that are arranged like a lattice is a, in the array of
the pin members 36 of the present invention, as shown in FIG. 4,
one row of pin members 36, out of each two adjacent rows of pin
members 36 perpendicular to the flow of the molten metal, is
shifted for half the pitch with respect to the other row of pin
members 36.
[0036] Accordingly, the distance between the adjacent pin members
36, which is conventionally adjusted to a, as shown in FIG. 4,
changes into b (=a.times.{square root over (5/2)}) according to the
Pythagorean theorem. Thus, the distance between the adjacent pin
members 36 can be made longer than in the case where the pin
members 36 are arranged like a lattice.
[0037] As this is done, the flow rate of the molten metal that can
flow between the pin members 36 can be made higher than in the case
of the conventional latticelike array, that is, the molten metal
can be made ready to flow.
[0038] In this case, the pin members 36 are staggered for half the
pitch, and the flow of the molten metal is not changed at all.
Therefore, the molten metal can thread through the widened spaces
between the pin members 36.
[0039] In this array of the pin members 36, the pin members 36 are
arrayed in zigzag.
[0040] However, the array of the pin members 36 is not limited to
this arrangement. As shown in FIG. 5, one row of pin members 36,
out of each two adjacent rows of pin members 36 (parallel to the
flowing direction of the molten metal in this case), may be shifted
for half the pitch with respect to the other row of pin members
36.
[0041] In this case also, the distance between the adjacent pin
members 36 changes from the conventional value a into
(=a.times.{square root over (5/2)}), as shown in FIG. 5. Thus, the
distance between the adjacent pin members 36 can be made longer
than in the case where the pin members 36 are arrayed like a
lattice so that the molten metal are ready to flow.
[0042] The zigzag array is not limited to the case where the pin
members 36 are arrayed in zigzag so that they are staggered for
half the pitch, and may be applied to various other cases. More
specifically, the basic array may be made rectangular instead of
being in the form of a lattice. A zigzag configuration shown in
FIG. 6, which has an angle different from that of FIG. 4, can be
obtained by staggering the pin members 36 for half the pitch from
the basic array in the longitudinal or crosswise direction (the
rectangular basic configuration is shifted for half the pitch in
the longitudinal direction so that the pin members 36 in the zigzag
array form a lattice inclined at a given angle in FIG. 6).
[0043] In this case, #1 and #4, #2 and #4, #4 and #6, of the pin
members 36 are located closest to one another. In this case also,
the zigzag array allows the molten metal to penetrate into gap
portions 37 between the pin members.
[0044] In this case also, a center line that connect the closest
adjacent pin members 36 is not perpendicular to the flowing
direction of the molten metal and crosses it diagonally at a given
angle. Accordingly, the distance between the pin members 36 can be
made longer than in the case where the adjacent pin members 36 are
arranged at right angles to the flow. Thus, the pin members 36 can
be prevented from hindering the molten metal flow, so that the flow
rate of the molten metal can be increased.
[0045] Further, the pin members 36 are arranged so that each two
adjacent rows of pin members 36 extend at right angles to or
parallel to the flowing direction of the molten metal and that the
other side row of the pin members 36 is shifted substantially for
half the pitch. However, the amount of shift of the pin members 36
is not limited to about half the pitch, and may be set at any value
provided that the molten metal can be caused to flow satisfactorily
in positions between the pin members 36.
[0046] The molten metal is introduced into the mold device 30
arranged in this manner through the sprue 33, diffused through the
runner 34, and introduced into the cavity 35. In this case, the
molten metal is diffused by means of the runner 34 as it is
introduced into the cavity 35, so that the molten metal uniformly
flows parallel in the cavity 35. Further, the molten metal is
introduced substantially parallel to the inner wall surface of the
cavity 35.
[0047] In this case, a pressure of about 250 tons, for example, is
applied to the molten magnesium alloy, and the introduction is
carried out to perform injection molding of the electronic
apparatus frame 20.
[0048] By this introduction, the molten metal can be diffused
throughout the regions between the pin members 36 that are arranged
in the aforesaid manner. Thus, the molten metal can be caused to
penetrate also into the gap portions 37 between the adjacent pin
members 36, as shown in FIGS. 4 to 6.
[0049] In the regions where the pin members 36 are arranged,
therefore, the cavity 35 can be filled with molten metal without
forming any unfilled portions, and thereafter, the molten metal
reaches air vents 38.
[0050] The air vents 38 serve to discharge air in the mold device
30 to the outside, and a molten metal reservoir 39 further
communicates with the air vents 38. Thus, the molten metal
introduced into the mold device 30 can reach the molten metal
reservoir 39 without producing voids in the cavity 35.
[0051] The temperature of the mold device 30 ranges from about
100.degree. C. to 350.degree. C., which is lower than the
temperature of the molten magnesium alloy ranging from about
580.degree. C. to 750.degree. C. When the molten metal is
introduced into the cavity 35, therefore, the molten metal is
immediately cooled and solidified as it touches the mold device
30.
[0052] However, the molten metal is subjected to the pressure as it
is introduced, as mentioned before, and the pin members 36 are
arrayed in the aforesaid manner. Accordingly, the molten metal
reaches the air vents 38 before it is solidified, and thereafter,
the molten metal is solidified.
[0053] After the molten metal is solidified, the upper mold 31 and
the lower mold 32 are released from engagement, and a molded piece
is pushed out by means of an ejector pin. Thereupon, the electronic
apparatus frame 20 having the pores 21 formed corresponding to the
aforesaid array of the pin members 36 is formed. Thus, in this
array of the pores 21 also, the distance between each two zigzagged
or adjacent pores 21 is elongated.
[0054] Basically, however, the number of pores 21 formed in the
same area is fixed, and there is no hindrance to the functionality
of heat release from the pores 21 and the diffusibility of sound
from the pores 21 as the speaker.
[0055] According to the manufacturing method for the mold device 30
and the electronic apparatus frame 20 constructed in this manner,
the pin members 36 are arranged so that one row of pin members 36,
out of each two adjacent rows of pin members 36 that extend at
right angles to or parallel to the direction of introduction of the
molten metal into the cavity 35, is shifted substantially for half
the pitch with respect to the other row of pin members 36.
Accordingly, the space between the adjacent pin members 36 can be
widened.
[0056] Thus, the molten metal can be circulated at a higher rate in
the regions between the pin members 36, and the molten metal can be
caused more smoothly to thread through the spaces between the pin
members 36 than in the case where the pin members 36 are arrayed
like a lattice.
[0057] Accordingly, the molten metal can be diffused also
throughout the gap portions 37 between the pin members 36 without
forming any unfilled portions.
[0058] Thus, the resulting electronic apparatus frame 20 has no
unfilled portions and suffers no malformation, so that the yield of
the electronic apparatus frame 20 can be improved.
[0059] If the pin members 36 are arrayed in any other zigzag form
than the one in which the other side of the adjacent pin members 36
is shifted substantially for half the pitch in the aforesaid
manner, a center line connecting the adjacent pin members 36 is not
perpendicular to the flow of the molten metal. In this case also,
therefore, the flow rate of the molten metal can be made higher
than in the case where the pin members 36 are arrayed like a
lattice.
[0060] In the case where the pin members 36 are arrayed in zigzag,
as compared with the case where the pin members 36 are arrayed in a
lattice, moreover, the adjacent pin members 36 are not arranged
parallel to the flowing direction of the molten metal. Accordingly,
the molten metal can be caused easily to penetrate into the gap
portions 37 between the pin members 36. Thus, formation of unfilled
portions and malformation of the electronic apparatus frame 20 can
be prevented.
[0061] According to the arrangement in which the pin members 36 are
arranged so that one row of pin members 36, out of each two
adjacent rows of pin members 36 that extend at right angles to the
direction of introduction of the molten metal into the cavity 35,
is shifted substantially for half the pitch with respect to the
other row of pin members 36, in particular, the pin members 36 can
prevent the molten metal from flowing in a straight line so that
the molten metal meanders between the pin members 36. Thus, the
molten metal can be allowed to penetrate particularly
satisfactorily into the spaces between the pin members 36.
[0062] Although the one embodiment of the present invention has
been described above, the present invention can be modified
variously. The following is a description of the modification.
[0063] According to the embodiment described above, the pin members
36 are arrayed in a zigzag form such that the other of the adjacent
rows of the pin members 36 is shifted substantially for half the
pitch or in any other zigzag form. Alternatively, however, the pin
members 36 may be arrayed like a lattice such that the direction of
introduction of the molten metal is inclined at a given angle to
the pin members 36 in this array, as shown in FIG. 9, for
example.
[0064] In this case also, a flow of the molten metal can be
produced such that the molten metal threads through the spaces
between the pin members 36, as indicated by arrows in FIG. 9. Thus,
in the case where the pin members 36 are arrayed like a lattice,
the molten metal can be diffused throughout the gap portions 37
between the pin members 36 by inclining the direction of
introduction of the molten metal.
[0065] Further, various modifications may be effected without
departing from the spirit of the present invention.
[0066] Additional advantages and modifications will readily occur
to those skilled in the art. Therefore, the invention in its
broader aspects is not limited to the specific details and
representative embodiments shown and described herein. Accordingly,
various modifications may be made without departing from the spirit
or scope of the general inventive concept as defined by the
appended claims and their equivalents.
* * * * *