JP3021296B2 - Box for electronic device, method of manufacturing the same, and method of using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a box for electronic equipment which houses a printed circuit board of the electronic equipment, a method of manufacturing the same, and a method of using the same.

[0002]

2. Description of the Related Art An engine control unit (hereinafter referred to as an "ECU") mounted on a vehicle and controlling an engine of the vehicle fixes a printed circuit board on which electronic circuit components including a microcomputer are mounted inside a box, and prints the printed circuit board. It is composed of a box sealed so as to wrap around the substrate.

As shown in FIGS. 8 and 9, the ECU 1 includes a printed circuit board 2 on which electronic circuit components 7 and connectors 6 are mounted, a box 3 for housing the printed circuit board 2 therein, and a box 3 Consists of a flat lid 4 that covers the opening of. The box body 3 has a container shape, and side plates 3a, 3b, 3c, 3d and a bottom plate 3e are integrally formed by an aluminum die casting method. In the side plate 3d, a connector opening 3f is formed according to the width and height of the connector 6 for connecting the connector 6 to a connector (not shown) outside the ECU 1.

As the material of the box 3, aluminum is generally employed because of its good electromagnetic shielding characteristics and heat radiation characteristics and its light weight. Aluminum is particularly suitable for automobiles that require a high degree of weight reduction, and can be relatively easily formed into a complex shape, thin-walled and flat shape by aluminum die casting. When a box-shaped product such as the box 3 is formed by the aluminum die casting method, the gate 8 is provided with the side plates 3a, 3b, 3c, and 3b for pouring molten aluminum (hereinafter, referred to as "molten metal"). In general, it is provided on one of the end faces on the opening side of 3d. In FIG.
The configuration of a casting mold 10 in which a gate 8 is provided at a joint between a side plate 3d and a bottom plate 3e is shown.

[0005] The casting mold 10 mainly includes a fixed mold 11 and a movable mold 1.
2. A cavity 14 which is formed of an injection plunger 13 and has a shape of a workpiece defined by an outer wall 11a of a fixed mold 11 and an inner wall 12a of a movable mold 12, and a melt 15
An injection sleeve 16 serving as a flow path for flowing the fluid into the cavity 14 is formed. In the case of this background art example, the shape of the work is the shape of the box 3. In the aluminum die casting method, the box body 3 is formed mainly by the following steps 1 to 3.

[0006] The molten metal 15 is poured into the cavity 14 through the injection sleeve 16 by the injection plunger 13 and filled therein. The filled molten metal 15 solidifies into the shape of the cavity 14 and the box 3 is formed. The formed box 3 is taken out of the casting mold 10. As shown in FIGS. 11 and 12, an unnecessary gate gate 9 remains on the bottom plate 3 e of the box 3 taken out from the casting mold 10, near the junction between the side plate 3 d and the bottom plate 3 e of the box 3. ,
The gate 9 needs to be cut and removed in the next step.

As shown in the figure below the arrow in FIG. 12, the gate 9 is cut and removed by a hammer or a press (not shown) along the gate cut line 9a shown in FIG.

[0008]

However, FIG.
As shown in the figure, when the plate thickness near the gate cut line 9a of the box 3 is as thin as the plate thickness t1 of the bottom plate 3e, the strength near the gate cut line 9a is insufficient. There is a problem that a notch 8b is generated toward the bottom plate 3e during cutting. Further, there is a problem that the vicinity of the gate cut line 9a is deformed even if the notch 8b does not occur in the bottom plate 3e.

The problem is that when the plate thickness near the gate cut line 9a is thin, the side plates 3a other than the side plate 3d of the box 3 are
Even if the position of the sprue 9 is changed to any of the end faces on the opening side of 3b, 3c, chipping or deformation occurs in any of the side plates 3a, 3b, 3c when the sprue gate 9 is cut or removed as described above. I can't avoid it. The present invention has been made to solve such a problem, and cuts and removes a gate of a box formed by an aluminum die casting method or the like without chipping on the box side and causing deformation or the like. It is an object of the present invention to provide a box for an electronic device, a method of manufacturing the same, and a method of using the same.

[0010]

According to a first aspect of the present invention, there is provided an electronic device box having a one-sided opening, which is formed by a casting method. Has a U-shaped notch on a part of one of the four side walls of the box, and the bottom wall side portion of the box corresponding to the opening of the gate gate equivalent part, The opening of the gate section is made thicker than the bottom wall so that the casting cast into the gate section can be cut and removed at the base of the gate section. .

According to a second aspect of the present invention, there is provided a box for an electronic device having a one-sided opening formed by a casting method. Partially has a U-shaped missing wall portion, the surface that partitions this missing wall portion,
A first edge surface parallel to a bottom wall of the box, a second edge surface extending from one end of the first edge surface to an opening surface of the one-sided opening, and another end of the first edge surface; A third edge surface extending to the opening surface of the one-sided opening, and extending from the first edge surface of the one-sided side wall having the missing wall portion to the outside of the box in a direction substantially perpendicular to the one-sided side wall. The bottom surface of the gate-gate-equivalent portion and the bottom wall surface of the box have a step.

According to a third aspect of the present invention, there is provided an electronic device box according to the second aspect, wherein a thickness t2 of the opening of the gate gate-equivalent portion is equal to the thickness of the box. Is larger than the thickness t1 of the bottom wall. The electronic device box according to the fourth aspect of the present invention is the third aspect of the present invention.
The electronic device box as described above, wherein the thickness t2 is twice to three times as large as the thickness t1.

The electronic device box according to claim 5 of the present invention is the electronic device box according to claim 1, 2, 3 or 4, wherein the casting method is an aluminum die casting method. It is characterized by. A method for manufacturing an electronic device box according to claim 6 of the present invention is the method for manufacturing an electronic device box according to any one of claims 1 to 5, wherein the method includes the steps of: A step of pouring and filling a molten metal from a gate gate into a cavity formed in the shape of the box between the two, and a step of removing a solidified product cast and solidified in the shape of the cavity from the fixed mold and the movable mold. And a step of cutting and removing a casting unnecessary portion cast into the gate and solidified and integrally formed with the casting at the root portion of the gate gate equivalent portion.

According to a seventh aspect of the present invention, there is provided a method of using an electronic device box according to any one of the first to fifth aspects, wherein the electronic device box is used. Is characterized by being used as an external device connection hole.

[0015]

According to the electronic device box of the present invention, the casting cast into the gate gate equivalent portion is cut at the base of the gate gate equivalent portion.
Since the opening of the gate gate equivalent portion is made thicker than the bottom wall so that it can be removed, the strength of the gate gate equivalent portion increases, and the casting cast into the gate gate equivalent portion is cut.
At the time of removal, there is an effect of preventing chipping and deformation occurring from the cut wall toward the bottom wall. It is preferable that the thickness t2 of the opening corresponding to the gate is set to be two to three times larger than the thickness t1 of the bottom wall of the box.

According to the second aspect of the present invention, since the bottom surface of the portion corresponding to the gate and the bottom wall surface of the box have a step, the casting cast into the portion corresponding to the gate. When the body is bent in the direction of the bottom wall, stress concentrates at the root of the cast body cast in the gate-gate-equivalent portion formed at the step, and this cast body is easily cut. According to the electronic device box of the present invention,
Since the opening corresponding to the gate gate is made thicker than the bottom wall, the molten metal easily flows on the bottom wall and the side walls, and there is an effect of improving the production quality of the box body by the aluminum die casting method.

Further, according to the method of manufacturing a box for electronic equipment according to the sixth aspect of the present invention, the opening of the part corresponding to the gate is made thicker than the bottom wall, or the bottom of the part corresponding to the gate is connected to the bottom. Since the bottom wall surface of the box has a step, when cutting and removing the casting cast into the gate gate equivalent part,
This has the effect of preventing chipping and deformation occurring from the notched wall portion toward the bottom wall and improving the manufacturing quality of the box.

Further, according to the method of using the electronic device box of the present invention, it is possible to prevent deformation of the bottom wall when cutting and removing the casting cast into the gate gate equivalent portion. Therefore, there is an effect that the external connection device or the like can be smoothly inserted into the inside of the box through the external device connection hole without the external device connection hole becoming narrow due to the deformation of the bottom wall.

[0019]

1 to 5 show an embodiment in which a box structure of an electronic apparatus according to the present invention is applied to a box body of an ECU mounted on an automobile. As shown in FIGS. 1 and 2, the ECU 19 controls the printed circuit board 2 on which the electronic circuit components 7 and the connectors 6 are mounted.
And a box 20 which surrounds the printed circuit board 2 and is held and sealed therein, and a flat lid 4 which covers the opening of the box 20. The box 20 has a container shape, and side plates 21, 22, 23, 24 and a bottom plate 25 are integrally formed by an aluminum die casting method. A gate 28 to be described later is formed at a joint between the side plate 24 and the bottom plate 25 so as to be thicker than the bottom plate 25. At the four inside corners of the box 20, a shelf 26 for placing the printed circuit board 2 and the flat lid 4 on top of each other inside the box 20 is formed so as to protrude, and the screw 2
7 are formed. A first edge surface 2 parallel to the bottom plate 25;
4b and the box body 20 from one end of the first edge surface 24b.
The connector opening 24a, which is separated from a second edge surface 24c extending to the opening surface of the opening and a third edge surface 24d extending from the other end of the first edge surface 24b to the opening surface, has a width corresponding to the width of the connector 6. The connector 6 formed on the side plate 24 according to the height and attached to the substrate 2 is connectable to a device or the like outside the ECU 19. A connector (not shown) for the ECU 19 to transmit and receive signals to and from a sensor device (not shown) outside the ECU 19 is connected to the connector 6.

The flat lid 4 is a plate made of, for example, aluminum and formed into a square having a side of 150 mm, for example, about 1 mm in thickness, for example, by press molding. A through-hole 31 is formed at a position suitable for the screw portion 27 of the box 20 for screw fixing to the shelf 26. An electronic circuit component 7 and a connector 6 are mounted on the printed circuit board 2 by soldering or screwing, and the four corners of the printed circuit board 2 are fixed to a shelf 26 of a box 20 by screws. 2
A through-hole (not shown) is formed at a position corresponding to the 0 screw portion 27. The printed circuit board 2 is mounted on the shelf 26 of the box 20.
The flat lid 4 is further placed on the printed circuit board 2 so as to be superimposed on the printed circuit board 2, and is screwed to the screw portion 27 by the screw 33 through the through hole 31 of the flat cover 4 and the through hole (not shown) of the printed circuit board 2. It is tightened and fixed.

Next, as shown in FIG. 3, a description will be given of a casting mold 40 for forming the box 20 by the aluminum die casting method and a casting process. The casting mold 40 is mainly composed of the fixed mold 4
1, a movable mold 42, and an injection plunger 43. When the fixed mold 41 and the movable mold 42 are fitted together, the fixed mold 41 and the movable mold 42 are movable so that the shape of the cavity 44 defined by the outer wall 41a of the fixed mold 41 and the inner wall 42a of the movable mold 42 becomes the shape of the work. A mold 42 is formed. In a part of the cavity 44, an injection sleeve 46 and a gate 28 serving as a flow path for flowing the molten metal 45 into the cavity 44 are formed.

The gate 28 forms a connecting portion between the cavity 44 forming the shape of the work which is the box body 20 and the injection sleeve 46. The thickness t2 of the gate 28 is
The bottom plate 25 is formed so as to have a plate thickness about 2 to 3 times as large as the plate thickness t1 of the bottom plate 25, and between the end of the bottom plate 25 on the gate 28 side and the injection sleeve 46 in the direction of the fixed mold 41. An extending step 28a and a root 28b of the injection sleeve 46 are formed. By the step portion 28a and the base portion 28b, the bottom plate 25 and the injection sleeve 46 are not formed on the same plane with respect to the movable mold 42, and the injection sleeve 46 described later is used.
Is prevented from being chipped toward the bottom plate 25 at the time of cutting or removing the slab.

The molten metal 45 is poured into the cavity 44 via the injection sleeve 46 by the injection plunger 43 and filled therein. The filled molten metal 45 solidifies into the shape of the cavity 44, and the box 20 is formed. The formed box 20 is taken out of the casting mold 40.

As shown in FIG. 4, the box 20 taken out of the casting mold 40 has a printed circuit board 2 and
7 to the size and thickness required for screw fixing
Are formed, the side plates 21, 22, 23, 24 and the bottom plate 25 are all formed in the same plate thickness and thin. However, as shown in FIG.
A gate gate 47 is formed in such a shape as to extend the gate 28, that is, the bottom plate 25 to the outside of the box 20. The gate gate 47 is formed by an injection sleeve 46 provided for flowing the molten metal 45 into the cavity 44, and is not required for the box 20 after molding. There is.

As shown in the figure below the arrow in FIG. 5, the gate gate 47 is cut and removed by a hammer or a press (not shown) along the gate gate cutting line 47a. At this time, since the plate thickness t2 of the gate 28 is about two to three times as large as the plate thickness t1 of the bottom plate 25 as described above, the gate 28 in the inward direction of the box 20 is formed from the gate cut line 47a. The strength of the bottom plate 25 has increased. Further, since the step 28a is provided between the bottom plate 25 and the injection sleeve 46,
When the gate gate 47 is bent in the direction of the bottom plate 25, stress concentration tends to occur at the base 28b of the gate gate 47.
Therefore, when the gate gate 47 is cut, no chipping occurs toward the bottom plate 25, and no deformation occurs near the gate gate cutting line 47a.

Here, the thickness of the gate 28 and the position where the gate 28 is provided will be described. As shown in FIG. 5, the thickness t2 of the gate 28 is set to the bottom plate 25 or the side plates 21 and 22 of the box body 20 in view of the point of being integrally formed by the aluminum die casting method and the restriction on the component mounting on the printed circuit board 2. , 2
It is desirable that the thickness is in a range of 2 to 3 times the thickness t1 of 3, 24. The reason for this is that if the thickness of the gate 28 is smaller than this,
This is because the strength of the gate 28 is insufficient, and there is a possibility that chipping may occur toward the bottom plate 25 as shown in the background art example. Further, if the thickness of the gate 28 is larger than this, the difference in the area where the molten metal flows from the gate 28 to the box body 20 becomes large, causing poor molten metal flow, and it becomes difficult to form the box body by aluminum die casting. It is.

The position where the gate 28 is provided is desirably set at the joint between the side plate 24 having the connector opening 24a and the bottom plate 25. The reason for this is shown in FIGS.
This will be described based on the comparative example shown in FIG. As shown in FIG.
In the comparative example, the side plate 2 without the connector opening 24a is formed.
3 shows an example in which a gate 38 is formed. In order to increase the strength of the sprue 38, the thickness of the sprue 38 is set to the same value as when the connector opening 24 a is formed in the side plate 24.
Or twice the thickness t1 of the side plates 21, 22, 23, 24
The thickness t3 is set to be three times as large as the thickness t3. Then, as shown in FIG. 7, by increasing the thickness of the gate 38 due to the restriction of the die casting method, the thickness of the side plate 23 is formed to a thickness t3 in the range from the opening side of the box 20 to the bottom plate 25. . Therefore, since the entire surface of the side plate 23 is formed with the plate thickness t3, when the gate 38 is formed on the side plate 23,
This leads to a significant increase in weight as compared with the case of forming the same. This is the same even when the gate 38 is formed on the side plate 21 or the side plate 22 other than the side plate 23 of the box 20.

For the above reasons, in order to satisfy the condition of light weight, which is particularly demanded for automobiles, a gate 28 is provided at the joint between the side plate 24 having the connector opening 24a and the bottom plate 25. It is desirable. According to the present embodiment, the gate thickness of the gate 28 provided at the junction between the side plate 24 having the connector opening 24a of the box 20 and the bottom plate 25 is set to be two to three times as thick as the bottom plate 25. Therefore, there is an effect that the strength of the bottom plate 25 forming the gate 28 increases.

According to the present embodiment, the strength of the bottom plate 25 forming the gate 28 is increased, and the step 28a is provided between the bottom plate 25 and the injection sleeve 46. When the gate 9 is cut or removed, there is an effect of preventing chipping generated from the connector opening 24a toward the bottom plate 25 and deformation near the gate cut line 47a.

Further, according to the present embodiment, the gate thickness of the gate 28 is set to be twice to three times the thickness t1 of the bottom plate 25 or the side plates 21, 22, 23, 24, so that the bottom plate 25 and the side plate 21 , 22, 23, and 24, the molten metal flows easily, and the effect of improving the manufacturing quality of the box body 20 by the aluminum die-casting manufacturing method is obtained. Furthermore, according to the present embodiment, since deformation near the gate cut line 47a can be prevented, the opening 24a for the connector 24a is formed by deformation of the bottom plate 25.
ECU 1 connected to connector 6 without narrowing
9 Connector for external sensor device etc.
4a can be smoothly inserted.

[Brief description of the drawings]

FIG. 1 is a sectional view taken along line II of FIG. 2 showing an ECU housing according to an embodiment of the present invention.

FIG. 2 is a partially broken perspective view of an ECU housing according to the embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view of a casting mold of a box body of an ECU housing according to the embodiment of the present invention.

FIG. 4 is a plan view of the box body before cutting and removing the gate gate of the ECU housing according to the embodiment of the present invention.

FIG. 5 is a sectional view taken along the line VV of FIG. 4 illustrating a process of cutting and removing the gate of the box body of the ECU housing according to the embodiment of the present invention.

FIG. 6 is a plan view of a box body before cutting and removing a gate gate of an ECU housing as a comparative example.

FIG. 7 is a view showing a gate gate cutting and removing process of a comparative example.
FIG. 7 is a sectional view taken along line VII-VII of FIG.

FIG. 8 is a partially cutaway perspective view of an ECU housing as a background art example.

9 is a cross-sectional view taken along the line IX-IX of FIG. 8 of the background art example.

FIG. 10 is a schematic cross-sectional view of a casting mold of a box body of an ECU housing as a background art example.

FIG. 11 is a plan view of a box body before cutting and removing a gate gate of an ECU housing as a background art example.

12 is a cross-sectional view taken along the line XII-XII of FIG. 11, illustrating a gate cut and removal process of the background art example.

[Explanation of symbols]

1, 19 ECU 2 Printed circuit board 3, 20 Box body 4 Flat lid 6 Connector 7 Electronic component 8, 28 Gate 9, 47 Gate gate (casting cast into gate gate equivalent part) 10, 40 Casting mold 11, 41 Fixed Mold 12, 42 Movable mold 13, 43 Injection plunger 14, 44 Cavity 15, 45 Melt 16, 46 Injection sleeve 21, 22, 23 Side plate 24 Side plate (side wall) 24a Connector opening (missing wall) 24b First edge surface 24c Second edge surface 24d Third edge surface 25 Bottom plate (bottom wall) 26 Shelf 28a Step (step) 28b Root

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI B22D 17/22 B22D 17/22 F H05K 5/02 H05K 5/02 JZ (56) References JP-A-7-108366 (JP) JP-A-7-32128 (JP, A) JP-A-6-79440 (JP, A) JP-A-7-336064 (JP, A) JP-A-52-65130 (JP, A) 5-502547 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B22D 31/00 B22C 9/06 B22C 9/08 B22D 17/00 B22D 17/20 B22D 17/22 H05K 5 / 02

Claims (7)

(57) [Claims] 1. A box-shaped electronic device box having a one-sided opening formed by a casting method, comprising a U-shaped notched wall portion in a part of one side wall among four side walls of the box, The bottom wall side portion of the box body corresponding to the opening corresponds to the opening of the gate gate, and the casting cast into the gate gate can be cut and removed at the base of the gate gate. A box for an electronic device, characterized in that the opening of the part corresponding to the gate is made thicker than the bottom wall. 2. A box-shaped electronic device box having a one-sided opening formed by a casting method, comprising a U-shaped cut-out part in a part of one-sided side wall among four side walls of the box, The surface partitioning the cut-off wall is a first parallel to the bottom wall of the box.
An edge surface, a second edge surface extending from one end of the first edge surface to the opening surface of the one-sided opening, and a third edge extending from the other end of the first edge surface to the opening surface of the one-sided opening. An edge surface, and a gate gate equivalent portion extending from the first edge surface of the one side wall having the missing wall portion to the outside of the box in a direction substantially perpendicular to the one side wall. An electronic device box, wherein a bottom surface and the bottom wall surface of the box have a step. 3. The electronic device box according to claim 2, wherein a thickness t2 of the opening of the gate gate-equivalent portion is larger than a thickness t1 of the bottom wall of the box. 4. The apparatus according to claim 3, wherein said thickness t2 is twice to three times as large as said thickness t1.
The box for an electronic device according to the above. 5. The electronic device box according to claim 1, wherein the casting method is an aluminum die casting method. 6. The method for manufacturing a box for an electronic device according to claim 1, wherein the box is formed between a fixed mold and a movable mold in the shape of the box. A step of pouring and filling a molten metal from a gate gate; a step of taking out a solidified casting cast into the shape of the cavity from the fixed mold and the movable mold; and a step of casting and solidifying the casting into the gate gate. And a step of cutting and removing a cast unnecessary portion integrally formed with the gate portion corresponding to the gate gate portion. 7. The method for using an electronic device box according to claim 1, wherein the missing wall portion is used as an external device connection hole.