JP7498065B2 - Circuit board housing structure - Google Patents

Description

The present invention relates to a substrate housing structure.

Conventionally, a substrate housing structure is known that includes a substrate and a housing as a case in which the substrate is housed with an opening on one side and has a side wall portion as a peripheral wall arranged opposite the outer edge of the substrate (see Patent Document 1).

In this substrate housing structure, the side wall is provided with a protrusion that acts as a rib that maintains the gap between the outer edge of the substrate and the inner surface of the side wall and positions the substrate relative to the housing. In this type of substrate housing structure, when the substrate is placed in the housing, the protrusion comes into contact with the outer edge of the substrate, and the substrate is positioned horizontally relative to the housing.

JP 2010-231895 A

Incidentally, in a substrate housing structure such as that disclosed in Patent Document 1, the substrate is positioned relative to the case by the ribs of the case so as to maintain a gap between the outer edge of the substrate and the inner surface of the peripheral wall. This gap between the outer edge of the substrate and the inner surface of the peripheral wall is set to be very narrow.

For this reason, when the case shrinks due to a temperature change, particularly from a high temperature to a low temperature, the ribs come into strong contact with the outer edge of the board, and the outer edge of the board may come into contact with the inner surface of the peripheral wall, filling in any gaps. When the outer edge of the board comes into contact with the inner surface of the peripheral wall in this way, a large load is placed on the board, which may adversely affect the electronic components mounted on the board and the electrical connections between the electronic components and the board.

The present invention was made in consideration of the problems inherent in the conventional technology. The object of the present invention is to provide a substrate housing structure that can reduce the load on the substrate caused by temperature changes.

The substrate housing structure according to this embodiment includes a substrate, and a case having a peripheral wall that is open on one side of the substrate to house the substrate and that faces the outer edge of the substrate, the peripheral wall is provided with a rib that maintains a gap between the outer edge of the substrate and the inner surface of the peripheral wall and positions the substrate relative to the case, and the peripheral wall is provided with a deformation portion that deflects the peripheral wall outward from the case when the rib or the peripheral wall comes into contact with the substrate due to a change in temperature.

The deformation portion is preferably a recess formed by cutting out the peripheral wall and into which the corner of the substrate is placed.

A cover that closes the opening is attached to the case, and the cover is preferably provided with a covering wall that covers the outer surface of the recess.

The present invention provides a substrate storage structure that can reduce the load on the substrate caused by temperature changes.

FIG. 2 is a perspective view of the substrate housing structure according to the present embodiment before a cover is attached. 2 is a perspective view of the substrate housing structure according to the embodiment with a cover attached thereto; FIG. 1 is a perspective view of a substrate and a case of a substrate housing structure according to an embodiment of the present invention. 2 is a top view of the substrate and case of the substrate housing structure according to the embodiment. FIG. FIG. 5 is an enlarged view of a main part of FIG. 4 . FIG. 4 is an enlarged view of a main portion of FIG. 3 .

The substrate housing structure according to this embodiment will be described in detail below with reference to the drawings. Note that the dimensional ratios in the drawings have been exaggerated for the sake of explanation and may differ from the actual ratios.

The substrate housing structure 1 according to this embodiment includes a substrate 3, and a case 7 that is open on one side of the substrate 3 to house the substrate 3 and has a peripheral wall 5 that is disposed opposite the outer edge of the substrate 3.

In addition, the peripheral wall 5 is provided with a rib 9 that maintains the gap S between the outer edge of the substrate 3 and the inner surface of the peripheral wall 5 and positions the substrate 3 relative to the case 7.

The peripheral wall 5 is provided with a deformation portion 11 that deflects the peripheral wall 5 outwardly of the case 7 when the rib 9 or the peripheral wall 5 comes into contact with the substrate 3 due to a change in temperature.

The deformation portion 11 is formed by cutting out the peripheral wall 5, and is a recess 13 in which the corner of the substrate 3 is placed.

A cover 15 that closes the opening is attached to the case 7. The cover 15 is provided with a cover wall 17 that covers the outer surface of the recess 13.

As shown in Figures 3 to 6, the substrate 3 is made of a printed circuit board or the like on which conductors (not shown) that form a circuit pattern are arranged. This substrate 3 is equipped with electronic components (not shown) and connectors 19, 19 that supply power to the substrate 3, send signals to the electronic components, and receive signals from the electronic components. These electronic components and connectors 19, 19 are electrically connected to the conductors of the substrate 3, for example, by soldering. Such a substrate 3 is housed in a case 7.

As shown in Figures 1 to 6, the case 7 is made of a resin with a larger linear expansion coefficient than the substrate 3. The case 7 is open on one side of the substrate 3 (the connectors 19, 19 side in this case) and has a peripheral wall 5 arranged opposite the outer edge of the substrate 3 so as to surround the outer edge of the substrate 3. Such a case 7 is provided with multiple (two in this case) fixing parts 21, and is attached to, for example, equipment mounted on a vehicle via the fixing parts 21. The peripheral wall 5 of the case 7 is provided with multiple (four in this case) ribs 9 that position the substrate 3 relative to the case 7.

As shown in Figures 3 and 4, the multiple ribs 9 are formed as a single member that is continuous with the peripheral wall 5 from the inner surface of the peripheral wall 5 and protrude inwardly into the case 7. The multiple ribs 9 abut against the outer edge of the substrate 3, and position the substrate 3 in the planar direction relative to the case 7 so as to maintain the gap S (see Figure 5) between the outer edge of the substrate 3 and the inner surface of the peripheral wall 5. Such multiple ribs 9 are provided in four locations, two near each of the fixing portions 21, 21 located diagonally on the substrate 3. By arranging the multiple ribs 9 on the diagonals of the substrate 3 in this way, the substrate 3 can be positioned with a minimum number of ribs 9.

Here, the case 7 is made of a resin with a larger linear expansion coefficient than the substrate 3. The gap S between the outer edge of the substrate 3 and the inner surface of the peripheral wall 5 is set very narrow to prevent the case 7 from becoming large. Therefore, when the case 7 and the substrate 3 contract due to a temperature change, particularly a temperature change from high to low, the linear expansion coefficient of the case 7 is larger than that of the substrate 3, so the multiple ribs 9 are strongly pressed against the outer edge of the substrate 3. At this time, the gap S between the outer edge of the substrate 3 and the inner surface of the peripheral wall 5 is very narrow, so there is a possibility that the outer edge of the substrate 3 and the inner surface of the peripheral wall 5 will come into contact with each other.

Such contact between the board 3 and the rib 9 or between the board 3 and the peripheral wall 5 due to temperature changes may place a large load on the board 3, pressing the board 3 inward. If such a large load is placed on the board 3, there is a concern that adverse effects such as damage to the electronic components and connectors 19, 19 mounted on the board 3 and damage to the electrical connections between the electronic components and connectors 19, 19 and the board 3 may occur. Therefore, the peripheral wall 5 is provided with a deformation portion 11 in order to reduce the load on the board 3 due to temperature changes.

As shown in Figures 3 to 6, the deformation portion 11 is a recess 13 formed by cutting out the peripheral wall 5. A plurality of recesses 13 (six in this example) are provided in the peripheral wall 5 so that the corners of the substrate 3 can be positioned therein. Since such recesses 13 are formed by cutting out the peripheral wall 5, they reduce the rigidity of the peripheral walls 5, 5 adjacent to the recesses 13.

By providing the recess 13 as the deformation portion 11 in the peripheral wall 5 in this way, when the substrate 3 and the rib 9 come into strong contact with each other or when the substrate 3 and the peripheral wall 5 come into contact with each other due to a temperature change, the peripheral wall 5 can be deflected outwardly from the case 7. In detail, as shown by the arrow in FIG. 6, the peripheral walls 5, 5 adjacent to the recess 13 can be deflected outwardly from the case 7.

Therefore, when a temperature change occurs such that the rib 9 strongly abuts against the substrate 3 or the peripheral wall 5 abuts against the substrate 3, the peripheral walls 5, 5 adjacent to the recess 13 bend outwardly toward the outside of the case 7. This bending of the peripheral walls 5, 5 reduces the pressure with which the inner surfaces of the rib 9 and peripheral wall 5 press the substrate 3 inwardly. Therefore, a large load is not applied to the substrate 3, and adverse effects such as damage to the electronic components and connectors 19, 19 mounted on the substrate 3, and damage to the electrical connections between the electronic components and connectors 19, 19 and the substrate 3 can be suppressed. A cover 15 is attached to the case 7 provided with the recess 13 as the deformation portion 11.

As shown in Figures 1 and 2, the cover 15 is made of an insulating material such as resin. This cover 15 is attached to the case 7 via multiple (six in this case) engagement parts 23 provided between the cover 15 and the case 7 so as to close an opening located on one side of the substrate 3 of the case 7. Such a cover 15 is provided with a cover wall 17 that covers the outer surface of the recess 13 when the cover 15 is attached to the case 7. By providing the cover wall 17 on the cover 15 in this way, the substrate 3 is not exposed to the outside from the recess 13 when the cover 15 is attached to the case 7, and the substrate 3 can be protected.

In such a substrate housing structure 1, the peripheral wall 5 is provided with a deformation portion 11 that deflects the peripheral wall 5 outwardly from the case 7 when a temperature change causes the rib 9 or the peripheral wall 5 to come into contact with the substrate 3. Therefore, when a temperature change occurs that causes the rib 9 or the peripheral wall 5 to come into contact with the substrate 3, the deformation portion 11 deflects the peripheral wall 5 outwardly from the case 7.

This deflection of the peripheral wall 5 reduces the pressure that the ribs 9 and the inner surface of the peripheral wall 5 exert on the substrate 3 inward. This reduces the load on the substrate 3 caused by temperature changes, and suppresses adverse effects on the electronic components mounted on the substrate 3 and the electrical connections between the electronic components and the substrate 3.

Therefore, in this type of substrate housing structure 1, the case 7 is provided with a deformation portion 11 that causes the peripheral wall 5 to bend outward from the case 7, thereby reducing the load on the substrate 3 due to temperature changes.

The deformation portion 11 is formed by cutting out the peripheral wall 5, and is a recess 13 in which the corner of the substrate 3 is placed. This allows the deformation portion 11 to have a simple structure, and the load on the substrate 3 due to temperature changes can be reduced without complicating the structure of the case 7.

Furthermore, the cover 15 is provided with a cover wall 17 that covers the outer surface of the recess 13. Therefore, when the cover 15 is attached to the case 7, the cover wall 17 prevents the substrate 3 from being exposed to the outside through the recess 13, and protects the substrate 3.

Although the present embodiment has been described above, the present embodiment is not limited to these, and various modifications are possible within the scope of the gist of the present embodiment.

For example, in the circuit board housing structure according to this embodiment, the deformation portion is a recess formed by cutting out the peripheral wall, but this is not limited to this. For example, a part of the peripheral wall may be formed of an elastic material as the deformation portion, and the peripheral wall may be deflected toward the outside of the case.

The ribs are arranged on the peripheral wall diagonally across the substrate, but this is not limiting and the ribs may be arranged anywhere on the peripheral wall.

REFERENCE SIGNS LIST 1: Substrate housing structure 3: Substrate 5: Peripheral wall 7: Case 9: Rib 11: Deformation portion 13: Recess 15: Cover 17: Cover wall S: Gap

Claims (2)

A substrate;
a case having an opening on one side of the substrate to accommodate the substrate and a peripheral wall disposed opposite an outer edge of the substrate;
Equipped with
a rib is provided on the peripheral wall to hold a gap between an outer edge of the substrate and an inner surface of the peripheral wall and to position the substrate relative to the case;
a deformation portion is provided in the peripheral wall, the deformation portion being configured to deflect the peripheral wall outwardly from the case when the rib or the peripheral wall comes into contact with the substrate due to a temperature change ;
A substrate accommodating structure , wherein the deformation portion is a recess formed by cutting out the peripheral wall and into which a corner of the substrate is placed . A cover for closing the opening is attached to the case,
The substrate storage structure according to claim 1 , wherein the cover is provided with a cover wall that covers an outer surface of the recess.

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