JP2004330509A - Electronic device housing and its molding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic device housing for individually bonding synthetic resin bodies having attaching parts and adhesive parts to a metal case, and its molding method. <P>SOLUTION: This electronic device housing is constituted so as to mold the synthetic resin bodies 8 at a specified predetermined position of the processed metal case 6. The synthetic resin bodies 8 have the attaching parts 8a and the adhesive parts 8b of the parts bonded to the metal case 6. The adhesive parts 8b are constituted individually and have the minimum adhesive areas. Before the synthetic resin bodies 8 are injected in the metal case 6, surface treatment for making adhesion strong is applied to the metal case 6. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electronic device housing configured by molding a synthetic resin in a metal case, and a method of molding the same. More specifically, the present invention relates to an electronic device housing in which a synthetic resin is partially formed and integrated to reinforce a metal case, mount an electronic device, and facilitate interior and exterior, and a method of molding the same.
[0002]
[Prior art]
Information communication devices and home appliances, such as mobile phones, mobile computers, and digital cameras, which employ a metal housing made of a magnesium alloy, an aluminum alloy, or the like, are increasing. For example, a housing of an electronic device made of a magnesium alloy has a beautiful metallic color. Although the weight is about 1.5 times heavier than plastics resin, the mechanical strength is twice to three times stronger, so that it can be made thinner, resulting in a lighter casing. In addition, metal has been spotlighted because of its electromagnetic shielding effect. For the molding of magnesium alloys, the injection molding method has recently been put to practical use from the conventional die casting method.
[0003]
Injection molding of magnesium alloy uses a special injection molding machine to inject the magnesium alloy into a mold to complete electronic components, housing, etc., and to perform advanced thin-wall molding that was not possible with the conventional die casting method. This is what we made possible. However, the obtained injection-molded products are liable to contain so-called gas, flow marks, and burrs, and at present, clean-up processing by cutting, grinding, etc. is indispensable as a pre-process for performing surface treatment. , Has not reached a satisfactory level in terms of cost. On the other hand, aluminum alloy is excellent in productivity because a molded product can be easily formed from a plate-shaped component by press working.
[0004]
As described above, recently, it has become possible to supply a material that can be subjected to metal press working with a magnesium alloy or an aluminum alloy, and the present inventors have paid attention to this. However, metal press working involves punching, cutting, bending, drawing, and the like from a plate material, and the shape of a molded product is limited, and the case itself cannot obtain a complicated shaped product such as an injection molded product.
[0005]
For example, even if the outer shape of the housing can be pressed with a desired design, screw holes for fixing an electronic circuit board, etc., pin holes for positioning, spacers, etc. are required in the housing, and furthermore, An internal partition, reinforcing ribs, and the like for increasing the section modulus are required. It is difficult to form a structure for this purpose simultaneously and integrally on the housing using the same material.
[0006]
In an example of a conventional case manufacturing method, a frame for mounting an electronic device component is separately provided, and the frame is inserted and fixed in a case (see Patent Document 1). (See Patent Document 2), or a method of inserting a metal housing into a resin molded body to form a molded article having a thin integrated structure (see Patent Document 3).
[0007]
In the manufacture of these electronic device housings, for example, as shown in FIG. 9, a synthetic resin body is injection-molded over the entire metal case 6 with the ribs 7 as a part of the reinforcement to enhance the adhesion with the metal case 6. . Further, recently, before forming the ribs 7 and the like, the surface of the metal case 6 is coated with at least one organic coating layer 30, that is, a lining or coating is performed, so as to enhance the heat fusion property with the thermoplastic resin. Is also being implemented.
[0008]
For example, a di (1,3,5-triazine-2,4,6-trithiol) triethanolamine complex (hereinafter referred to as a triazinethiol derivative) is used to form the coating layer 30. This triazine thiol derivative has been proposed (for example, see Patent Document 4).
[0009]
Electronic equipment housings in which the metal housing and the resin are integrated as described above are known. In order to mount an electronic device on a resin part with an integrally molded product of a metal and a resin, the resin had to be formed over the entire metal case to have a strong structure. For this reason, the structure becomes complicated, there is still room for improvement in terms of weight reduction and cost, and since the housing of electronic equipment is a product to be mass-produced in particular, a manufacturing method and a molding method with higher production efficiency are desired. Have been.
[0010]
[Patent Document 1]
JP-A-8-236951 [Patent Document 2]
JP 2002-158461 A [Patent Document 3]
JP 2000-114742 A [Patent Document 4]
JP-A-2-233666
[Problems to be solved by the invention]
The present invention has been made under the above-mentioned technical background, and is particularly useful when applied to a metal case made of an aluminum alloy, and achieves the following objects.
SUMMARY OF THE INVENTION An object of the present invention is to provide a lightweight and simple electronic device housing and a method for molding the electronic device housing by partially utilizing the goodness of the housing of a metal electronic device and the goodness of a synthetic resin to partially integrate them. Is to do.
It is another object of the present invention to provide an electronic device housing having high productivity and mass productivity, and a method of molding the same.
It is still another object of the present invention to provide an electronic device housing whose shape and structure can be freely designed and a method of molding the same.
[0012]
[Means for Solving the Problems]
The present invention employs the following means to achieve the above object.
The electronic device housing according to the first aspect of the present invention includes a metal case processed for housing the electronic device and an independent island formed and formed at a predetermined position on the surface of the metal case. And a synthetic resin body having a mounting portion for mounting the electronic device. The mounting portion in the present invention means a screw hole, a pin hole for positioning, a spacer, a partition, a reinforcing rib, and the like.
[0013]
An electronic device housing according to a second aspect of the present invention is characterized in that, in the first aspect, a plurality of the attachment portions are provided on one island and one adhesive portion.
An electronic device housing according to a third aspect is characterized in that, in the first aspect, the metal of the metal case is an aluminum alloy.
[0014]
An electronic device housing according to a fourth aspect of the present invention is the electronic device housing according to the third aspect, wherein the surface of the aluminum alloy is immersed in one or more aqueous solutions selected from ammonia, hydrazine, and a water-soluble amine compound. A polybutylene terephthalate and / or a polyphenylene sulfide resin as the synthetic resin body is adhered to a surface of an aluminum alloy.
[0015]
A method for forming a housing of an electronic device according to a fifth aspect of the present invention includes a step of installing a metal case processed for housing the electronic device in a mold, and an independent island formed by molding at a predetermined position on the surface of the metal case. A step of partitioning a cavity for bonding a synthetic resin body having a bonding portion bonded to the surface and a mounting portion for providing the electronic device into a mold, and injecting the synthetic resin into the cavity. And forming a housing of the electronic device.
[0016]
In a sixth aspect of the present invention, in the method of molding an electronic device housing according to the fifth aspect, the cavity forms the plurality of attachment portions on one island and one adhesive portion.
The method of molding an electronic device housing according to a seventh aspect of the present invention is the invention according to the fifth or sixth aspect, wherein the molding step is uniformly performed on each of the cavities via a plurality of runners having a shape that can be uniformly molded on the plurality of cavities. It is characterized in that the resin is injected.
[0017]
An eighth aspect of the present invention is directed to the method of forming an electronic device housing according to the fifth or sixth aspect, wherein the surface of the aluminum alloy is formed of one or more aqueous solutions selected from ammonia, hydrazine, and a water-soluble amine compound before the partitioning step. Wherein the synthetic resin body is polybutylene terephthalate and / or polyphenylene sulfide resin.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. An example in which the electronic device housing of the present invention is applied to a portable telephone will be described. FIG. 1 is a front view of a portable telephone provided with a housing of the present invention. The portable telephone 1 is composed of a telephone main body 2 composed of a metal case and a synthetic resin. Inside the telephone main body 2, electronic devices such as ICs for realizing the function of the telephone are mounted. .
[0019]
The telephone main body 2 is composed of a case cover 3 and a back surface main body 4 and is divided into two by a division surface at the center in the thickness direction. That is, the case cover 3 is disposed on the upper surface of the telephone main body 2, and the back surface main body 4 is disposed on the rear surface. The case cover 3 functions as a control panel, and a plurality of push buttons 5 are arranged to form a key group. The push button 5 drives contacts (not shown) on a printed circuit board arranged in the back surface main body 4. The case cover 3 and the back surface main body 4 are integrally fixed by fixing means (not shown) such as screws or notches.
[0020]
FIG. 2 is a cross-sectional view of the case cover 3 taken along line XX of FIG. The outer surface of the case cover 3 is formed of a metal case 6 made of an aluminum alloy in this example. The metal case 6 is manufactured by pressing an aluminum alloy plate. The processing method is known and will not be described in detail here, and the case is treated as a completed metal case 6. In the case of press working, a general-purpose plate material can be used, and since press working is excellent in productivity, it can be manufactured at low cost. The metal case 6 has excellent mechanical strength, but also has a function of efficiently shielding electromagnetic waves generated from electronic components such as ICs or electromagnetic waves from other electronic devices.
[0021]
The surface of the metal case 6 is usually subjected to a surface treatment by a known method such as a chemical conversion treatment or a painting in response to a request for improvement of corrosion resistance, abrasion resistance, decorative property and the like. Further, the inner surface of the metal case 6 is subjected to a treatment for improving the molding adhesiveness of the synthetic resin body as described later. Further, on the inner surface of the metal case 6, a rib 7 made of a thermoplastic resin and a synthetic resin body 8 partially having a mounting portion are integrally fixed for partition and reinforcement. The ribs 7 in the present embodiment are not necessarily required members. This fixation is heat-sealed by a method described later and integrated with the metal case 6.
[0022]
In the embodiment of the present invention, the thermoplastic resin for integrally molding the ribs 7 and the mounting portions is integrally fixed to the metal case 6 by heat fusion.
The thermoplastic resin preferably has mechanical strength and physical properties. Examples thereof include polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), polyamide resin (PA), polyacetal (POM), polycarbonate (PC), and polyester. It is selected from one or more selected from resins, ABS resins (ABS) and the like. Preferably, polybutylene terephthalate (PBT) and / or polyphenylene sulfide (PPS) resin is preferable because of strong adhesion (fixation) with an aluminum alloy.
[0023]
The reason for this adhesion is not clear, but the exothermic reaction of ammonia, hydrazine, or a water-soluble amine compound for pretreatment adsorbed on the aluminum alloy with polybutylene terephthalate (PBT) or polyphenylene sulfide (PPS) resin. It is estimated that In some cases, high-strength fibers such as metal fibers, carbon fibers, and glass fibers may be mixed with these thermoplastic resins in order to adjust the coefficient of linear expansion to the aluminum alloy.
[0024]
As a surface treatment method of the present embodiment, a case where an aluminum alloy is particularly applied to a metal case will be described. The following processing is performed for the aluminum alloy metal case. After the surface treatment and the cleaning treatment, a treatment for forming a fine etching surface on the aluminum alloy surface is performed as a pretreatment in order to increase the adhesiveness of the thermoplastic resin to the aluminum alloy.
[0025]
That is, the aluminum alloy is first immersed in a basic aqueous solution (ph> 7), and then the aluminum alloy is washed with water. By immersion in a basic aqueous solution, the surface of the aluminum alloy dissolves as aluminate ions while releasing hydrogen, and the surface of the aluminum alloy is shaved and a new surface comes out. As described above, the alkali etching is performed, but the acid etching may be used.
[0026]
Next, the treated aluminum alloy metal case 6 is immersed in one or more aqueous solutions selected from ammonia, hydrazine and / or a water-soluble amine compound. By this treatment, fine irregularities are generated on the surface of the metal case 6 and these nitrogen-containing compounds are adsorbed. Before the synthetic resin is injection-molded as described above, a process for firmly bonding the synthetic resin body 8 to the metal case 6 is performed. The synthetic resin body 8 which is a thermoplastic resin composition is injection-molded in the metal case 6 having been subjected to such a treatment by the method described below.
[0027]
FIG. 3 shows a cross section of a mold configuration for molding the synthetic resin body 8 forming the mounting portion 8 a into the metal case 6. In the present embodiment, the mounting portion 8a includes a tapped hole for screwing a screw, a boss fitted into a shaft, a pin hole for inserting a pin, a spacer for positioning a printed circuit board, a rib for reinforcing the metal case 6, It means a partition or the like for partitioning the internal space of the metal case 6. The movable mold 9 has a concave portion formed in a shape corresponding to the outer shape of the metal case 6, and the molded metal case 6 is inserted into the concave portion so as to match. The fixed die 10 is provided with a spool 13 for injecting the molten resin of the synthetic resin body 8, and defines a cavity corresponding to the mounting portion 8 a and a bonding portion 8 b of a portion bonded to the metal case 6.
[0028]
A gate 11 is provided so as to be electrically connected to the cavity, and a runner 12 and a spool 13 are connected to the gate 11. The cavity is a space partitioned so as to form the mounting portion 8a and the bonding portion 8b. After the movable mold 9 is closed, the synthetic resin body 8 which is a thermoplastic resin is injected into the cavity through the gate 11 to form the mounting portion 8a. On the surface of the metal case 6, an adhesive portion 8b having a slightly larger area than the mounting portion 8a is formed.
[0029]
The bonding portion 8b of the mounting portion 8a does not bond over the entire metal case 6. The bonding surface of the mounting portion 8a is extremely small as compared with the conventional case, but since the surface treatment is performed, the bonding is performed firmly. When there are a plurality of attachment portions 8a, the length and diameter of the runner 12 are determined so that the synthetic resin body 8 as a thermoplastic resin is uniformly injected into each attachment portion 8a.
[0030]
That is, the shape of the runners 12 is set so that each mounting portion 8a is cooled and solidified from one spool 13 to the plurality of runners 12 according to the size of the cavity. More specifically, it is known that general molding conditions are good if the lengths L1 and L2 from the spool 13 to each gate 11 are substantially the same. Since the mounting portions 8a are scattered on the surface of the metal case 6 in an island shape, it is easy to design the lengths L1 and L2 from the spool 13 to the gate to be substantially the same.
[0031]
FIG. 4 shows an example in which a plurality of mounting portions 8a such as tapped holes are provided in the same bonding portion 8b. Since the gate 11 is provided on the bonding portion 8b, the number of gates is one in this example. In this case, the number of gates 11 can be reduced even if the number of mounting portions 8a is large, and accordingly the number of runners 12 is reduced, which is effective in terms of manufacturing efficiency. In the case of a configuration having the mounting portion 8a which is close, a plurality of the mounting portions 8a may be combined into one bonding portion 8b and synthetic resin may be injected from one gate 11.
[0032]
FIG. 5 is another example showing this example. The island A is obtained by combining five attachment portions 8a with one adhesive portion 8b, and the island B is obtained by combining three attachment portions 8a with one adhesive portion 8b. The size of the bonding portion 8b is adjusted to the size of the mounting portion 8a, and is preferably substantially the same size (capacity of the resin) and the minimum necessary size. Also in this configuration, the number of gates, the diameter and the length of the runner, and the like are changed so that the synthetic resin body 8 is simultaneously and simultaneously injected into each bonding portion 8b as uniformly as possible.
[0033]
5 is branched from one spool 13 into two runners 12, and a synthetic resin body 8 indicated by islands A and B is formed. The size and the capacity of the island B portion are preferably the same. For example, when the amount of resin required for the island A portion is different from the amount of resin required for the island B portion, the size of one of the runner 12 and the gate 11 is changed. Alternatively, the resin may flow and fill the islands A and B at the same time.
[0034]
FIG. 6 shows another embodiment, and is an example of a configuration in which the mounting portion 21 is arranged on the frame side of the metal frame 20 of a mobile electronic device. The metal frame 20 is a pressed thin-plate frame made of aluminum alloy or the like, and has a mounting portion 21 made of a synthetic resin mounted thereon by molding. Each of the arranged mounting portions 21 is provided in an isolated island shape at a distance. FIGS. 7 and 8 show a configuration in which the mounting portion 21 is formed on the metal frame 20 via the bonding portion 22. FIG. FIG. 7 is a diagram illustrating a form in which a single spool 23 is ejected to a plurality of bonding parts 22 via a plurality of runners 24 provided according to the number of bonding parts 22. FIG. 3 is an external view schematically showing a form in which a synthetic resin is injected into a metal frame 20 by a skeleton.
[0035]
FIG. 8 shows a partial cross-sectional view of the mold configuration. Although a plurality of runners 24 are partially provided on one adhesive portion 22, the runner 24 is installed so that the synthetic resin is uniformly injected and the mounting portion 21 and the adhesive portion 22 are solidified. In this manner, it is possible to simultaneously inject the metal frame 20 to the bonding portion 22 which is separated from one spool 23 in an island shape, and it is possible to firmly bond the metal frame 20 by the above-described processing. As a result, it is not necessary to cover the entire metal frame 20 with the synthetic resin, and only the necessary part can be formed, so that the formed product can be reduced in weight.
[0036]
According to the configuration of the present invention, the synthetic resin body having the minimum mounting portion 8a (21) and the bonding portion 8b (22) is individually installed at any position of the metal case 6 (20). Is possible, and the degree of freedom in mounting the electronic device is widened.
[0037]
In the above-described embodiment, the case of the mobile phone and the case of the mobile computer are used. However, the present invention can be applied to any electronic device such as a digital camera and a hard disk. Needless to say.
[0038]
【The invention's effect】
As described in detail above, the electronic device housing of the present invention can be easily formed despite the configuration in which the thermoplastic synthetic resin having the mounting portion of the metal case is partially and individually adhered to the surface of the metal case in an island shape. It is a configuration that can be integrated without peeling off. As a result, it is possible to manufacture a product in which the amount of the synthetic resin in the bonding portion to the metal case is minimized. Therefore, a lighter product can be manufactured, and the cost can be reduced. In particular, the electronic device housing is extremely effective for mass production.
[Brief description of the drawings]
FIG. 1 is a front view of a housing of a portable telephone to which the present invention is applied.
FIG. 2 is a cross-sectional view of the case cover when cut along a line XX in FIG. 1;
FIG. 3 is a cross-sectional view showing a configuration of a mold for injection-molding a synthetic resin body having one attachment portion at one bonding portion on the surface of a metal case.
FIG. 4 is a cross-sectional view showing a configuration of a mold for injection-molding a synthetic resin body having a plurality of mounting portions on one bonding portion on the surface of a metal case.
FIG. 5 is a partial plan view showing a configuration in which a plurality of adhesive portions having a plurality of attachment portions are arranged in an island shape.
FIG. 6 is an external view showing a housing configuration in which an attachment portion is provided on a frame side of a metal case according to another embodiment.
FIG. 7 is an external view showing a configuration of a spool and a runner by skeleton when molding the housing of FIG. 6;
FIG. 8 is a partial cross-sectional view showing a configuration of a mold when forming a mounting portion of the housing of FIG. 7;
FIG. 9 is a cross-sectional view showing an adhesive configuration of a conventional synthetic resin body to a metal case.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Portable telephone 2 ... Telephone body 3 ... Case cover 5 ... Push button 6, 20 ... Metal case 7 ... Rib 8 ... Synthetic resin body 8a, 21 ... Mounting part 8b, 22 ... Adhesive part

Claims (8)

A metal case processed to house electronic devices,
An electronic device which is an independent island formed and formed at a predetermined position on the surface of the metal case, and which is made of a synthetic resin body having a bonding portion bonded to the surface and a mounting portion for providing the electronic device. Housing. The electronic device housing according to claim 1,
An electronic device housing, comprising a plurality of the attachment portions on one island and one adhesion portion. The electronic device housing according to claim 1,
The electronic device case, wherein the metal of the metal case is an aluminum alloy. The electronic device housing according to claim 3,
The surface of the aluminum alloy is immersed in one or more aqueous solutions selected from ammonia, hydrazine, and a water-soluble amine-based compound. An electronic device housing to which butylene terephthalate and / or polyphenylene sulfide resin is adhered. A process of installing a metal case processed for storing electronic devices in a mold,
It is an independent island formed by molding at a predetermined position on the surface of the metal case, and is used for bonding a synthetic resin body having a bonding portion bonded to the surface and a mounting portion for providing the electronic device. A partitioning step of partitioning the cavity into a mold,
A molding step of injecting the synthetic resin into the cavity to mold an electronic device housing. The method for molding an electronic device housing according to claim 5,
The method according to claim 1, wherein the cavity is formed with a plurality of attachment portions on one island and one adhesion portion. The method for molding an electronic device housing according to claim 5 or 6,
Wherein the molding step is such that synthetic resin is uniformly injected into each of the cavities through a plurality of runners having a shape capable of being uniformly molded into the plurality of cavities, wherein Body molding method. The method for molding an electronic device housing according to claim 5 or 6,
Before the partitioning step, the surface of the aluminum alloy is immersed in one or more aqueous solutions selected from ammonia, hydrazine, and a water-soluble amine compound,
The method for molding an electronic device housing, wherein the synthetic resin body is a polybutylene terephthalate and / or a polyphenylene sulfide resin.

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