US20010001978A1

US20010001978A1 - Electronic apparatus, manufacturing method therefor, and mold device

Info

Publication number: US20010001978A1
Application number: US09/737,872
Authority: US
Inventors: Takashi Hosoi; Nobuyuki Takaki; Yasuo Ono
Original assignee: Toshiba Corp
Current assignee: Toshiba Corp
Priority date: 1998-06-19
Filing date: 2000-12-18
Publication date: 2001-05-31
Also published as: JP2000005859A; WO1999065632A1; TW404162B; CN1306466A

Abstract

An electronic apparatus such as a portable computer comprises an electronic apparatus frame and a raised portion provided on that region of the electronic apparatus frame which engages an ejector pin projecting from inside a mold device and formed thicker than the other part of the electronic apparatus frame.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of Application No. PCT/JP99/01764, filed Apr. 2, 1999. [0001]
This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 10-173024, filed Jun. 19, 1998, the entire contents of which are incorporated herein by reference. [0002]

BACKGROUND OF THE INVENTION

This invention relates to a manufacturing method for an electronic apparatus frame, and more particularly, to a case where a molded piece is taken out of a mold device.

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. In either of these molding methods, which use different equipment mechanisms, an alloy melted at 580° to 750° is injected into a mold device of about 100° to 350° and molded.

FIG. 1 shows a configuration of a conventional electronic apparatus frame. In this electronic apparatus frame 1, a molten metal is introduced through a sprue 2, a molten metal inlet portion of a mold device (which will be described with reference to that portion of this drawing which corresponds to the shape of the electronic apparatus frame just molded and the sectional view of FIG. 2 showing the mold device 10), 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 an air vent 5. Further, a molten metal reservoir 6 is coupled to the air vent 5. When the molten metal is introduced through the sprue 2, therefore, air can be discharged to the outside through the air vent 5. Thereupon, the frame can be formed without containing any voids therein.

A molded piece is formed as the molten metal is thus introduced into the

mold device

10. In order to take out the molded piece from the cavity 4, the molded piece is pushed out by means of ejector pins 7.

In order to enable the molded piece to be pushed out by means of the

ejector pins

7, the ejector pins 7 are provided in the mold device 10, as shown in FIG. 2.

In the case where a light metal is used as the material of the electronic apparatus frame 1, the electronic apparatus frame 1 is thinned in general. If a magnesium alloy is the material, the wall thickness of the frame ranges from about 0.7 to 1.0 mm. When the molded piece is pushed out of the mold device, therefore, those regions which are pushed in by means of the ejector pins 7 may be hollowed by the push force, possibly leaving push indentations 8 shown in FIG. 3.

If the electronic apparatus frame 1 is provided with a large number of irregularities, such as bosses and ribs, the push force increases correspondingly. In some cases, therefore, the push indentations 8 may be formed more clearly in the pushed regions of the electronic apparatus frame 1 that is thinned, as mentioned before.

Such deformation that is attributable to the push force is not limited to the case of the light metal for use as the material, and is also caused in the case of a synthetic resin. In the case of the synthetic resin, the deformation appears as a phenomenon such as blushing.

If the

push indentations

8 or depressions are formed, the external appearance is not favorable, and the products are not mass-producible.

When the

ejector pins

7 are pushed in, moreover, not only the pushed regions but also the entire molded piece may possibly subjected to deformation such as deflection by means of the push force. If such deformation occurs, it cannot serve for the utilization of the electronic apparatus frame 1, and inevitably causes malformation.

BRIEF SUMMARY OF THE INVENTION

This invention has been contrived in consideration of these circumstances, and its object is to provide an electronic apparatus having a frame that cannot be deformed when it is pushed out of a mold device by means of ejector pins, a manufacturing method therefor, and the mold device.

According to a preferred embodiment, an electronic apparatus of this invention comprises a frame and a raised portion provided on that region of the frame which engages an ejector pin projecting from inside a mold device and formed thicker than the peripheral portion of the engaging region at the least.

In a mold device of this invention including a first mold and a second mold for forming a frame of a metallic material and having an ejector pin adapted to push out a molded piece from the first mold after the molded piece is formed, moreover, a depression is formed in that part of the first mold from which the ejector pin projects so that the part pushed out by means of the ejector pin forms a raised portion.

Further, an electronic apparatus manufacturing method of this invention for molding an electronic apparatus including a frame of a metallic material by means of a mold device formed having a depression such that a part pushed out by means of an ejector pin forms a raised portion comprises a flowing process for diffusing a molten metal into the mold device, a solidifying process for solidifying the molten metal introduced into the mold device in the flowing process, thereby forming a frame, and an unloading process for pushing out a raised portion of a molded piece formed in the solidifying process, thereby taking out the molded piece from the mold device.

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

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 sectional view showing a configuration of a prior art mold device; [0020]
FIG. 3 is a perspective view showing a state of push indentations in the prior art electronic apparatus frame; [0021]
FIG. 4 is a perspective view showing the shape of a portable computer as an electronic apparatus according to one embodiment of this embodiment; [0022]
FIG. 5 is a perspective view showing a configuration of an electronic apparatus frame of the electronic apparatus of the same embodiment; [0023]
FIG. 6 is a plan view showing the shapes of raised portions and ribs of the electronic apparatus frame constituting the electronic apparatus of the same embodiment; [0024]
FIG. 7 is a sectional view showing a configuration of a mold device of the same embodiment; [0025]
FIGS. 8A and 8B are views showing a manufacturing method for the electronic apparatus having the electronic apparatus frame of the same embodiment, in which FIG. 8A is a view showing a state in which a first mold and a second mold of the mold device are disengaged, and FIG. 8B is a view showing a state in which a molded piece is pushed out of the first mold by means of ejector pins; [0026]
FIG. 9 shows a flowchart for the electronic apparatus manufacturing method of the same embodiment; [0027]
FIG. 10 is a partial sectional view showing a state of an electronic apparatus frame of an electronic apparatus according to a modification of the present invention and illustrating the formation of a mound portion; [0028]
FIG. 11 is a partial sectional view showing a state of an electronic apparatus frame of an electronic apparatus according to a modification of the present invention and illustrating the formation of a thick-walled portion projecting into the electronic apparatus frame; and [0029]
FIG. 12 is a partial sectional view showing a state of an electronic apparatus frame of an electronic apparatus according to a modification of the present invention and illustrating the formation of a thick-walled portion projecting outward from the electronic apparatus frame. [0030]

DETAILED DESCRIPTION OF THE INVENTION

One embodiment of the present invention will now be described with reference to FIGS. [0031] 4 to 8B.
FIG. 4 is an external view showing the shape of a [0032] 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 design 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.
In the description to follow, the frame that is applied to the [0033] portable computer 10 or some other electronic apparatus will be described as an electronic apparatus frame 20.
FIG. 5 shows the shape of the [0034] electronic apparatus frame 20 that cannot be deformed even if it is pushed out by means of ejector pins 39 according to the present invention. In this drawing, raised portions 21 are formed protruding for a given height from the frame body of the electronic apparatus frame 20, and moreover, ribs 22 that extend in gentle slopes from the top portion of each raised portion 21 toward the peripheral portion are arranged at intervals of, for example, about 90°. FIG. 6 is a plan view of this state taken from the topside.
A [0035] mold device 30 arranged in the following manner is used to manufacture the electronic apparatus frame 20 having the aforementioned construction and prevent the push force of the ejector pins 39 from creating push indentations.
The [0036] mold device 30 shown in FIG. 7 is composed of a first mold 31 and a second mold 32 that are in engagement with each other, and has a cavity 35 formed therein as the first mold 31 and the second mold 32 engage each other. In introducing a molten metal into the cavity 35, it is introduced through a sprue 33, a molten metal inlet, and is diffused by means of a runner 34 so that a substantially parallel molten metal flow is introduced into the cavity 35.
The molten metal, diffused and introduced by means of the [0037] runner 34, fills the cavity 35, and is introduced into depressions 36 that are formed in the first mold 31. The depressions 36 are formed by depressing those regions of the first mold 31 for the ejector pins 39 to a given depth, and the raised portions 21 are provided on a molded piece 50 as the molten metal get into the depressions 36 and solidifies.
If the wall thickness of the [0038] electronic apparatus frame 20 ranges from about 0.7 to 1.0 mm, for example, the height of projection of the raised portions 21 ranges from about 0.84 to 1.2 mm, which is about 20% greater than the wall thickness of the frame.
The [0039] depressions 36 are located individually on ejector projection regions 37 in the first mold 31. Through holes 38 are formed in the first mold 31 so as to be continuous with the ejector projection regions 37, and the ejector pins 39 can get into and out of the through holes 38, individually.
The ejector pins [0040] 39 are passed through the through holes 38, individually. The ejector pins 39 are movable along the through holes 38. When they project downward, their respective lower end portions project from the inner wall surface of the cavity 35 of the first mold 31.
A [0041] spring 40 for use as urging means is located on each ejector pin 39. The springs 40 serve to give urging force to the ejector pins 39 so that the pins 39 project from the inner wall surface of the cavity 35 of the first mold 31. To apply this urging force, the one-end side of each spring 40 is attached to a stationary mold 41. The stationary mold 41, which is located above the first mold 31, can be driven in the vertical direction.
The [0042] stationary mold 41 is provided with recesses 42 having a given size. The recesses 42 are designed to receive the respective upper ends of the springs 40. If the stationary mold 42 is driven downward, therefore, corresponding urging force can be applied to the ejector pins 39.
The raised [0043] portions 21 are formed on the molded piece 50 as the molten metal flows into the depressions 36. In some cases, however, the raised portions 21 alone may fail to prevent general deformation, such as deflection, of the electronic apparatus frame 20 when those portions are pushed in by means of the ejector pins 39. To avoid this, the molded piece 50 has the ribs 22 that are arranged at the given angular intervals around the raised portions 21.
The [0044] ribs 22 are in the form of slopes with a sufficient length that gently decline from the outer peripheral edge portion of the top portion of each raised portion 21. Since the ribs 22 gently decline from the depressions 36, moreover, the molten metal in the depressions 36 can easily go around.
Further, the [0045] ribs 22 have a length such that the molded piece 50 never undergoes deformation such as deflection when the raised portions 21 are pressed by means of the ejector pins 39. Furthermore, the length of the ribs 22 is restricted in consideration of the attachment of any other electronic component or the like.
In order to form these [0046] ribs 22 on the molded piece 50, grooves 43 corresponding to the ribs 22 are formed around the depressions 36 of the mold device 30. The aforesaid ribs 22 can be formed in a manner such that the molten metal gets into the grooves 43.
The molten metal that fills the inside of the [0047] cavity 35 reaches an air vent 44 on the other end side of the runner 34 with respect to the cavity 35. The air vent 44 serves to discharge air in the cavity 35 from the cavity 35 to the outside. Thus, the molten metal introduced into the cavity 35 can prevent generation of voids therein as it reaches a molten metal reservoir 45.
The following is a description of a method for manufacturing the [0048] electronic apparatus frame 20 by means of the mold device 30 constructed in this manner. This manufacturing method is shown in FIG. 9.
First, the molten metal is caused to flow into the [0049] cavity 35 and fill it (flowing process). Thereafter, the loaded molten metal is solidified by cooling (solidifying process). The molded piece 50 must be taken out of the cavity 35 when it is formed (unloading process).
Accordingly, the [0050] first mold 31 and the second mold 32 must be disengaged from each other, as shown in FIG. 8A, to allow the molded piece 50 to be taken out. When the first mold 31 and the second mold 32 are disengaged and opened, however, the molded piece 50 is left adhering to the first mold 31 on the molded piece 50 that is formed having a rib structure and bosses the electronic apparatus frame 20 usually has or irregularities such as the aforesaid depressions 36 and the ribs 22.
Therefore, the molded [0051] piece 50 in this state expected to be taken out of the first mold 31. To attain this, the molded piece 50 is pushed out by means of the ejector pins 39, as shown in FIG. 8B.
In this case, the raised [0052] portions 21 and the ribs 22 are formed on the molded piece 50 as the molten metal is introduced into the mold device 30. Since the raised portions 21 and the ribs 22 are provided on the regions for the projection of the ejector pins 39, however, the raised portions 52 receive the push force of the ejector pins 39 and are pushed out.
The molded [0053] piece 50 can be pushed out of the mold device 30 by means of the ejector pins 39 so that it is ready to be removed outward. Since those portions of the molded piece 50 which correspond to the sprue 33 and the runner 34 in the mold device 30 are not disengaged yet, however, they are cut off after the molded piece 50 is taken out. Thus, the electronic apparatus frame 20 is formed.
According to the manufacturing method for the [0054] electronic apparatus frame 20 constructed in this manner and the mold device 30, the engaging portions at which the molded piece 50 is pushed out by means of the ejector pins 39 are formed of the raised portions 21. If the push force of the ejector pins 39 is received by means of the raised portions 21, therefore, the electronic apparatus frame 20 cannot be subjected to any apparent deformation such as depressions if the electronic apparatus frame 20 is thinned.
Accordingly, the external appearance of the [0055] electronic apparatus frame 20 can be improved, and at the same time, occurrence of malformation that is attributable to deformation during the extrusion can be prevented. Thus, the formation of the raised portions 21 improves the efficiency of mass production for the electronic apparatus frame 20.
Since the [0056] ribs 22 are provided at the given angular intervals so that they extend like gentle slopes from the top portion of each raised portion 21, moreover, malformation of the electronic apparatus frame 20, such as depression or deflection, can be prevented more securely.
Since the thinned [0057] electronic apparatus frame 20 is reinforced by means of the ribs 22, in particular, the general shape of the electronic apparatus frame 20 can be satisfactorily prevented from suffering deflection.
Since the [0058] mold device 30 is previously formed having the depressions 36 and the grooves 43 before the raised portions 21 and the ribs 22 are formed, moreover, the molded piece 50 having the raised portions 21 and the ribs 22 can be formed by only introducing the molten metal into the cavity 35 of the mold device 30 and allowing it to solidify. If the ejector pins 39 are received by means of the raised portions 21, therefore, the molded piece 50 can be prevented from being deformed when the molded piece 50 is removed. Thus, the formation of the electronic apparatus frame 20 can be improved in efficiency, and therefore, its cost can be lowered.
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. [0059]
According to the embodiment described above, the raised [0060] portions 21 are shaped so that their respective top portions are substantially circular, as shown in FIGS. 5 and 6. Alternatively, however, the top portion of each raised portion 21 may have a square shape or any other shape.
Further, the [0061] ribs 21 are not limited to the form of gentle slopes, and may be designed so that they extend for a given length without varying in height, for example.
Furthermore, the raised [0062] portions 21 may be replaced with any other structures such as protrusions that are formed by mounding those portions of the electronic apparatus frame 20 which engage the ejector pins 39 so that the ejector pins 39 can be caused to abut against their corresponding mound portions 23, as shown in FIG. 10. In this case, the mold device 30 is internally shaped corresponding to this arrangement so that the mound portions 23 can be e formed by only introducing the molten metal into the mold device 30.
Further, the [0063] mound portions 23 for use as the protrusions may be replaced with thick-walled portions 24 that are formed on the engaging portions for the ejector pins 39 so as to project into the electronic apparatus frame 20, as shown in FIG. 11. Each thick-walled portion 24 includes a top portion 24 a and a slanting portion 24 b that gently declines from the top portion 24 a toward the peripheral portion. In this configuration, the slanting portion 24 b serves for reinforcement when each ejector pin 39 abuts against the top portion 24 a.
In FIG. 12, moreover, each thick-[0064] walled portion 24 is formed projecting into the electronic apparatus frame 20. Alternatively, however, a thick-walled portion 25 may be formed projecting outward from the electronic apparatus frame 20, as shown in FIG. 11. In this case, as in the aforesaid case, the thick-walled portion 25 has a top portion 25 a and a slanting portion 25 b. If a plurality of thick-walled portions 25 are formed on the bottom wall surface of the lower frame 14 of the portable computer 10 shown in FIG. 4, for example, the thick-walled portions 25 can be made to function as contact portions to engage a disk or the like.
Further, various modifications may be effected without departing from the spirit of the invention. [0065]
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. [0066]

Claims

What is claimed is:

1. An electronic apparatus comprising:

a frame; and

a raised portion provided on that region of said frame which engages an ejector pin projecting from inside a mold device and formed thicker than the peripheral portion of said engaging region at the least.

2. An electronic apparatus according to

claim 1

, wherein said raised portion is surrounded by ribs for reinforcement.

3. An electronic apparatus comprising:

a frame; and

a protrusion provided on that region of said frame which engages an ejector pin projecting from inside a mold device and formed projecting from the peripheral portion of said engaging region at the least.

4. In a mold device including a first mold and a second mold for forming a frame of a metallic material and having an ejector pin adapted to push out a molded piece from the first mold after the molded piece is formed,

a depression being formed in that part of said first mold from which the ejector pin projects so that the part pushed out by means of the ejector pin forms a raised portion.

5. A mold device according to

claim 4

, wherein said depression is surrounded by grooves for forming ribs for reinforcement.

6. A method of manufacturing an electronic apparatus, comprising the steps of:

introducing molten metal into a mold having a first mold section and a second mold section, said first mold section has a recess so that a molding has a thick-wall part that may contact an ejector pin;

solidifying the molten metal in the mold, thereby to form a molding; and

pushing the thick-wall part of the molding with the ejector pin, thereby to take the molding from the mold.