CHASSIS STRUCTURE FOR PORTABLE ELECTRONIC DEVICES

A chassis structure is disclosed. A chassis includes a plate-like body in which a foam layer is located between a pair of fiber-reinforced resin plates, and a frame body formed of a thermoplastic resin and joined to a peripheral portion of the plate-like body. The plate-like body is configured such that its peripheral portion is formed by an ear-like joint portion where the pair of fiber-reinforced resin plates are joined together without the foam layer located therebetween, thereby sealing the foam layer inside the pair of fiber-reinforced resin plates. The frame body is joined to the plate-like body in a state where the frame body is in contact with the joint portion.

PRIORITY CLAIM

The present application claims benefit of priority under 35 U.S.C. §120, 365 to the previously filed Japanese Patent Application No JP2015-011390 with a priority date of Jan. 23, 2015, which is incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Technical Field The present invention relates to electronic devices in general, and particularly to a structure that can be applied to a chassis of an electronic device.

2. Description of Related Art

Chassis of various electronic devices, such as laptop personal computers (laptop PCs), tablet personal computers (tablet PCs), mobile phones, etc., should be thin, light, and strong. In view of this, a plate-like chassis material in which a foam layer is “sandwiched” between prepreg plates (fiber-reinforced resin plates) having reinforcing fibers such as carbon fibers impregnated with a thermosetting resin such as an epoxy resin is widely used for the chassis of electronic devices.

According to the prior art, an anchor effect is generated by injection-molding the thermoplastic resin on the end face of the plate-like body to cause the thermoplastic resin to enter the foam layer sandwiched between the fiber-reinforced resin plates so that high joining strength can be obtained. However, with this structure, it is difficult to control the amount of the thermoplastic resin entering the foam layer, which complicates the manufacturing management process.

Consequently, it would be desirable to provide an improved chassis structure that allows for a simpler manufacturing management process.

SUMMARY OF THE INVENTION

In accordance with a preferred embodiment of the present invention, a chassis structure includes a plate-like body in which a foam layer is located between a pair of fiber-reinforced resin plates, and a frame body formed of a thermoplastic resin and is joined to a peripheral portion of the plate-like body. The plate-like body is configured such that the peripheral portion of the plate-like body is formed by an ear-like joint portion where the pair of fiber-reinforced resin plates are joined together without the foam layer located therebetween, thereby sealing the foam layer inside the pair of fiber-reinforced resin plates. The frame body is joined to the plate-like body in a state where the frame body is in contact with the joint portion.

With this configuration, since the foam layer is sealed between the pair of fiber-reinforced resin plates, the thermoplastic resin forming the frame body does not enter the foam layer when the frame body is being joined to the plate-like body. As a result, the manufacturing process of the chassis is much simpler, and the manufacturing cost can also be reduced. Further, since the plate-like body and the frame body are joined together by contacting the frame body with the joint portion provided in the peripheral portion of the plate-like body, the contact area between the plate-like body and the frame body can be sufficiently ensured so that high joining strength can be obtained therebetween.

The flat plate portion may extend to an edge of at least a part of the chassis material. Accordingly, high strength can be ensured over the entire external shape of the chassis material, and since a seam between the fiber-reinforced resin plates and the frame body does not appear on the outer surface, the external appearance quality becomes even higher. As a result, it is possible to reduce or eliminate a post-treatment step, such as a surface treatment, for covering the seam.

The joint portion may have a bent portion formed by bending the flat plate portion at the edge of the chassis material and the frame body may be joined to an inner surface of the bent portion. Accordingly, since the outer surface of the chassis and an outer surface of a side surface of the chassis can be integrally formed by the fiber-reinforced resin plates, it is possible to achieve even higher strength.

All features and advantages of the present disclosure will become apparent in the following detailed written description.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Referring now to the drawings and in particular toFIG. 1, there is depicted a perspective view of an electronic device16having a lid14constituted by an electronic device chassis12formed of a chassis material10, according to a preferred embodiment of the present invention. In this embodiment, there is shown by way of example a configuration in which the electronic device chassis12formed of the chassis material10is applied to the lid14of the electronic device16as a laptop PC. As shown, the electronic device16includes a device body20having a keyboard device18, and the rectangular flat plate-like lid14having a display device22composed of a liquid crystal display and so on, and is of the clamshell type in which the lid14is coupled to the device body20via left and right hinges24so as to be openable and closable. Various electronic components, not illustrated, such as a board, an arithmetic processing unit, a hard disk device, and a memory, are housed in the device body20.

The lid14includes the electronic device chassis12having a back cover12aand a front cover12b. The back cover12ais a cover member covering side surfaces and a back surface of the lid14and is formed of the chassis material10according to this embodiment. The front cover12bis a resin cover member covering a front surface of the lid14jointly with the display device22. A pair of left and right antennas26,26are provided in the electronic device chassis12near its upper end portion. The antennas26,26are used for transmission and reception of radio waves that are used in wireless communications and so on.

Next, the configuration of the back cover12aof the lid14and the chassis material10forming the back cover12awill be described in detail.

The overall configuration of the back cover12awill be described.FIG. 2is a plan view showing the configuration of the back cover12aof the lid14and showing the inner side of the back cover12awhere the display device22is received.

As described above, the back cover12ais formed of the chassis material10. As shown inFIG. 2, the back cover12ais a panel-like cover member in which a wall portion28is formed upright on the periphery thereof to serve as side surfaces of the electronic device chassis12along its four sides.

The antennas26are provided on an inner surface of the back cover12aat its upper edge portion. A pair of recesses29in which the hinges24are respectively disposed are cutout-formed at a lower edge portion of the back cover12a.

Next, a specific configuration of the chassis material10forming the back cover12awill be described.FIG. 3is a cross-sectional view taken along line111-Ill ofFIG. 2andFIG. 4is a cross-sectional view taken along line IV-IV ofFIG. 2.

As shown inFIGS. 2 to 4, the chassis material10includes a plate-like body34of a stacked structure in which a foam layer32is sandwiched between a pair of upper and lower fiber-reinforced resin plates (prepreg layers)30and a frame body36joined to peripheral portions40,41of the plate-like body34.

Each fiber-reinforced resin plate30is a prepreg in which reinforcing fibers are impregnated with a thermosetting resin such as an epoxy resin. In this embodiment, it is made of a carbon fiber-reinforced resin (CFRF) using carbon fibers as the reinforcing fibers. The reinforcing fibers may be other than the carbon fibers and may be made of any of various materials, for example, metal fibers such as stainless steel fibers and inorganic fibers such as glass fibers.

The foam layer32is a soft spacer provided between the pair of fiber-reinforced resin plates30and serving to space these hard fiber-reinforced resin plates30from each other. By providing the foam layer32, the section modules of the plate-like body34in its thickness direction increases to create a light and strong structure. The foam layer32is formed by, for example, a foam sheet of polypropylene or the like.

As shown inFIGS. 3 and 4, the plate-like body34has a structure such that its peripheral portions along its four sides are formed by an ear-like joint portion38where the pair of fiber-reinforced resin plates30are joined together without sandwiching the foam layer32therebetween, thereby sealing the foam layer32inside the pair of fiber-reinforced resin plates30. The joint portion38is obtained by joining the fiber-reinforced resin plates30together by pressing when forming the plate-like body34. The plate-like body34may have a stacked structure of five or more layers in which foam layers32are respectively sandwiched between adjacent two of three or more fiber-reinforced resin plates30. In this case, the joint portion38is formed by joining the three or more fiber-reinforced resin plates30together.

The peripheral portions along the four sides of the plate-like body34of this embodiment differ in structure between the upper edge portion (upper side), where the antennas26are disposed, of the back cover12aand the other left and right side edge portions (left and right sides) and lower edge portion (lower side) of the back cover12a.

As shown inFIG. 3(see alsoFIG. 2), in the peripheral portion40along the left side, the right side, and the lower side other than the upper side where the antennas26are disposed, the joint portion38has a flat plate portion38aflush with and extending along an outer surface42of the chassis material10(back cover12a) and a bent portion38bformed by bending the flat plate portion38aperpendicularly inward of the back cover12aat the edge. The length of the flat plate portion38amay be set to substantially zero and the bent portion38bmay be formed by bending the joint portion38near the boundary with the foam layer32. The fiber-reinforced resin plate30on the inner side (lower side inFIG. 3) of the plate-like body34is formed, near the joint portion38, with an inclined surface30ainclined toward the outer-side fiber-reinforced resin plate30.

The frame body36is joined to the plate-like body34by injection-molding a thermoplastic resin on inner surfaces of the flat plate portion38athe bent portion38b, and the inclined surface30a. The frame body36is a frame-like portion where non-illustrated screw holes, rib shapes, and so on for attaching the front cover12bare formed. As the thermoplastic resin forming the frame body36, it is preferable to use, for example, a polyethylene resin or a polypropylene resin, or use may be made of a fiber-reinforced resin (e.g., GFRP) in which such a resin contains reinforcing fibers such as glass fibers. In this embodiment, the frame body36is formed of a non-conductive material.

Accordingly, in the peripheral portion40shown inFIG. 3, the flat plate portion38aof the joint portion38where the fiber-reinforced resin plates30,30are joined together extends to the outer edge of the chassis material10and the frame body36is joined to the inner side thereof. Further, the outer surface of the wall portion28of the peripheral portion40is mostly formed by the bent portion38bof the joint portion38and the frame body36is joined to the inner side thereof.

Consequently, in the peripheral portion40, the joining area (contact area) between the fiber-reinforced resin plates30and the frame body36can be sufficiently ensured by the joint portion38, and therefore, the plate-like body34and the frame body36can be joined together with high joining strength. Further, since the outer surface42of the chassis material10is formed to reach the edge by the high-strength fiber-reinforced resin plates30and the lower-strength frame body36is joined to the inner side thereof, it is possible to ensure the strength of the entire peripheral portion40. Further, since a seam between the fiber-reinforced resin plates30and the frame body36does not appear on the outer surface42, the external appearance quality is high, and since a post-treatment such as a surface treatment for covering the seam is not required, the manufacturing cost can be reduced.

Next, as shown inFIG. 4(also inFIG. 2), in the peripheral portion41along the upper side where the antennas26are disposed, the joint portion38has a flat plate portion38aflush with the outer surface42of the chassis material10(back cover12a) and extending slightly from an end portion of the foam layer32along the outer surface42. Therefore, differently from the flat plate portion38aof the peripheral portion40shown inFIG. 3, the flat plate portion38aof the peripheral portion41does not reach the edge of the chassis material10. Also in the peripheral portion41, the fiber-reinforced resin plate30on the inner side (lower side inFIG. 4) of the plate-like body34is formed with an inclined surface30a.

The frame body36is joined to the plate-like body34by injection-molding the thermoplastic resin on an inner surface and an end face of the flat plate portion38aand an inner surface of the inclined surface30a. In the case of this configuration, the frame body36is formed so as to be flush with and extend along the outer surface42of the back cover12aand to protrude inward of the back cover12aat the edge.

Therefore, in the peripheral portion41shown inFIG. 4, the flat plate portion38aof the joint portion38where the fiber-reinforced resin plates30are joined together does not extend to the edge of the chassis material10and the frame body36is joined to the inner side and the lateral side thereof. Further, the wall portion28of the peripheral portion41is formed by the frame body36and the antennas26are provided on the inner side of the wall portion28.

Consequently, in the peripheral portion41, although smaller than in the case of the peripheral portion40, the joining area (contact area) between the fiber-reinforced resin plates30and the frame body36can be sufficiently ensured by the joint portion38, and therefore, the plate-like body34and the frame body36can be joined together with high joining strength. Further, since the fiber-reinforced resin plates30made of the conductive material are not disposed on the outer side of the antennas26and instead the frame body36made of the non-conductive material is disposed, high sensitivity of the antennas26is ensured. In the case where the antennas26are not required to be disposed due to a specification of the electronic device16or the like, the peripheral portion41may have the same structure as the peripheral portion40shown inFIG. 3.

The shapes of the peripheral portions40,41may of course be other than those shown inFIGS. 3 and 4. For example, the peripheral portion40may be a peripheral portion40A having a shape with the bent portion38bomitted as shown inFIG. 5. In the peripheral portion40A, a flat plate portion38aof a joint portion38extends to the edge of a chassis material10and a frame body36is joined to the inner side of the flat plate portion38a.

For example, the peripheral portion41may be a peripheral portion41A in which a flat plate portion38aof a joint portion38is formed stepped from an outer surface42of a chassis material10as shown inFIG. 6. In the peripheral portion41A, compared to the peripheral portion41shown inFIG. 4, a frame body36is joined also to the outer side of the flat plate portion38ain addition to the inner side and the lateral side thereof and therefore the joining strength of the frame body36to the plate-like body34becomes even higher.

FIG. 7is a cross-sectional view for explaining a method of manufacturing the chassis material10, according to a preferred embodiment of the present invention. When manufacturing the chassis material10, first, a pair of planar fiber-reinforced resin plates30, each having a predetermined external shape (e.g., a rectangular shape) are prepared, then a planar foam layer32(e.g., a foam sheet) having a predetermined external shape (e.g., a rectangular shape) smaller than each of the fiber-reinforced resin plates30is sandwiched therebetween, and then the three layers (i.e., two resin plates30and one foam layer32) are pressed in a stacking direction thereof. In this event, a plate-like body34of a sandwich structure is formed in which the foam layer32is sealed inside by an ear-like joint portion38that is formed in peripheral portions40,41by pressing together the pair of fiber-reinforced resin plates30at portions where the foam layer32is not sandwiched therebetween.

Subsequently, as shown inFIG. 7, the plate-like body34is set in a mold44and then a molten thermoplastic resin is injected into a cavity46through an injection port44a, thereby injection-molding the thermoplastic resin so as to be in contact with the joint portion38of the plate-like body34. AlthoughFIG. 7shows by way of example a method of manufacturing the peripheral portion40shown inFIG. 3, this can also be applied, almost as it is, to a method of manufacturing the peripheral portion41shown inFIG. 4. As a result, as shown inFIGS. 3 and 4, a frame body36is formed at the peripheral portions40,41of the plate-like body34so that the chassis material10is formed.

As described above, in the chassis material10according to the present to embodiment, the plate-like body34is configured such that its peripheral portions40(40A),41(41A) are formed by the ear-like joint portion38where the pair of fiber-reinforced resin plates30,30are joined together without sandwiching the foam layer32therebetween, thereby sealing the foam layer32inside (at a central portion of) the pair of fiber-reinforced resin plates30,30, while the frame body36is joined to the plate-like body34in the state where the frame body36is in contact with the joint portion38.

Accordingly, since the foam layer32is sealed between the fiber-reinforced resin plates30, the thermoplastic resin forming the frame body36does not enter the foam layer32when joining the frame body36to the plate-like body34, and therefore, the manufacturing management thereof is easy and thus the manufacturing cost thereof can be reduced. Further, since the plate-like body34and the frame body36are joined together by contacting the frame body36with the joint portion38provided in the peripheral portions40,41of the plate-like body34, the contact area between the plate-like body34and the frame body36can be sufficiently ensured to obtain high joining strength therebetween so that the strength of the chassis material10also becomes high.

The joint portion38has the flat plate portion38aextending along the outer surface42of the chassis material10and the frame body36is joined to the inner surface of the flat plate portion38a(seeFIGS. 3 to 6). Accordingly, the outer surface42of the chassis material10is formed to be planar by the flat plate portion38a(and the frame body36) so that the external appearance quality is high. Herein, in the peripheral portions40,40A shown inFIGS. 3 and 5, the flat plate portion38aextends to the edge of the chassis material10. Therefore, high strength can be ensured over the entire external shape of the chassis material10and, further, since a seam between the fiber-reinforced resin plates30,30and the frame body36does not appear on the outer surface42, the external appearance quality becomes even higher and it is possible to reduce or eliminate a post-treatment such as a surface treatment for covering the seam.

In this case, in the peripheral portion40shown inFIG. 3, the joint portion38has the bent portion38bformed by bending the flat plate portion38aat the edge and the frame body36is joined also to the inner surface of the bent portion38b, In other words, according to the chassis material10, by providing the joint portion38having no foam layer32in the peripheral portion40of the plate-like body34, it is possible to draw the joint portion38to form the bent portion38bwithout being hindered by the foam layer32. Consequently, since the outer surface42of the chassis material10and the outer surface of the wall portion28serving as the side surface of the chassis material10can be integrally formed by the fiber-reinforced resin plates30, it is possible to achieve even higher strength and to further reduce a post-treatment such as a surface treatment.

As has been described, the present disclosure provides an improved chassis structure that allows for a simpler manufacturing management process.

The present invention is not limited to the above-described embodiment and changes can of course be made freely within a range not departing from the gist of the present invention. For example, in the above-described embodiment, there is shown by way of example the configuration in which the chassis material10is used as the electronic device chassis12of the lid14forming the electronic device16, but the chassis material10may be used for the device body20.

Further, the chassis material10can be used as a chassis material of various electronic devices such as a tablet PC, a desktop PC, a smartphone, and a cellular phone, other than the laptop PC. For example, as shown inFIG. 8, in the case of an electronic device50as a tablet PC, since it has a touch-operable display device52at the front of an electronic device chassis54, a rectangular flat plate-like back cover (back plate)54ais preferably formed of a chassis material10. In this event, preferably, the upper side, where an antenna26is provided, of the electronic device chassis54has the same structure as the peripheral portion41shown inFIG. 4, while the other three sides of the electronic device chassis54have the same structure as the peripheral portion40shown inFIG. 3.