WO2011013509A1 - Electronic device - Google Patents

Abstract

A stress generated on a circuit board due to fastening of a casing is reduced, and the occurrence of peeling or the like of solder is inhibited and prevented, thereby improving reliability. A casing (1) is formed by including a case (2) and a base (3) and forming fastening flanges (2b, 3b) for being fastened to each other so as to be capable of storing a circuit board (4) therein by screwing the fastening flanges (2b, 3b) to be fastened to each other. A peripheral portion of the circuit board (4) is disposed between the fastening flanges (2b, 3b), and between the peripheral portion of the circuit board (4) and the fastening flanges (2b, 3b), an elastic body (10) is provided, respectively. The circuit board (4) is sandwiched between the fastening flanges (2b, 3b) through the elastic body (10).

Description

Electronic equipment

The present invention relates to an electronic device in which a circuit board on which an electronic circuit is formed is housed, and more particularly, to an apparatus for improving the circuit board mounting structure.

As a circuit board mounting structure in an electronic device, for example, a case in which a circuit board is stored is configured so that a storage space is formed by combining two case members, and a circuit is formed at the peripheral portion of the two case members. A structure in which a substrate is sandwiched is well known in the art (see, for example, Patent Document 1).
FIG. 8 shows an example of such a conventional mounting structure. Hereinafter, this conventional mounting structure will be described with reference to FIG.

The housing 50 for housing the circuit board 53 is composed of a case 51 and a base 52, and the housing space 50a in which the circuit board 53 is housed becomes a base 51 and a base by screwing them together at the periphery. 52 is defined.
That is, the peripheral portions of the case 51 and the base 52 are formed with connecting pieces 51a and 52a which are parallel to each other for screwing. Then, the case 51 and the base 52 are fastened by the fastening screw 54 so that the peripheral edge portion of the circuit board 53 is positioned between the connecting pieces 51a and 52a and penetrates the connecting pieces 51a and 52a, and the circuit board 53 is also fastened. Is sandwiched between the coupling pieces 51a and 52a, and the sealing screw 55 is filled around the fastening screw 54 to provide a waterproof measure.

However, in the conventional mounting structure as described above, since the circuit board 53 is directly supported by the case 51 and the base 52, stress due to the fastening force between the case 51 and the base 52 is applied. It acts on the circuit board 53 and tends to cause peeling or cracking of the soldering of the electronic component with deterioration over time, which may affect the reliability of the electronic device.
JP 2002-134970 A

The present invention has been made in view of the above circumstances, and an electronic device having a highly reliable circuit board mounting structure that reduces stress on the circuit board, suppresses the occurrence of solder peeling, and the like. It is to provide.

According to an aspect of the present invention, a circuit board on which an electronic circuit is formed;
An electronic device comprising a housing for storing the circuit board,
The housing includes a first case member and a second case member, and the first and second case members are each formed with a fastening flange for fastening to each other. By being screwed in the fastening flange, the first and second case members are fastened and the circuit board can be housed inside,
The circuit board has a peripheral portion positioned between the fastening flanges, and an elastic body is interposed between the peripheral portion of the circuit board and the fastening flange. There is provided an electronic device which is sandwiched between fastening flanges via the elastic body.

According to the present invention, the stress to the circuit board due to screwing of the housing can be suppressed as much as possible, the peeling of the soldering of the circuit board due to the stress can be avoided, and the life of the solder can be extended, This provides an effect that a highly reliable electronic device can be provided.

It is a schematic diagram which shows typically the 1st structural example of the attachment structure of the circuit board in embodiment of this invention. It is a schematic diagram which shows typically the 2nd structural example of the attachment structure of the circuit board in embodiment of this invention. It is a schematic diagram which shows typically the 3rd structural example of the attachment structure of the circuit board in embodiment of this invention. It is a schematic diagram which shows typically the 4th structural example of the attachment structure of the circuit board in embodiment of this invention. It is a schematic diagram which shows typically the 5th structural example of the attachment structure of the circuit board in embodiment of this invention. It is a schematic diagram which shows typically the 6th structural example of the attachment structure of the circuit board in embodiment of this invention. It is a whole perspective view which shows the structural example of the surface protection measures of the nameplate stuck on the outer surface of housing | casings, such as an electronic device, and various seals. It is a schematic diagram which shows typically the attachment structure example of the conventional circuit board.

DESCRIPTION OF SYMBOLS 1 ... Housing | casing 2 ... Case 2b ... Connecting flange 3 ... Base 3b ... Connecting flange 4 ... Circuit board 10 ... Elastic body 11 ... Thin plate-like elastic body 12 ... Adhesive 13 ... Tubular elastic body 14 ... O-ring-like elasticity body

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 7.
The members and arrangements described below do not limit the present invention and can be variously modified within the scope of the gist of the present invention.
First, a first configuration example will be described with reference to FIG.
First, an electronic device S according to an embodiment of the present invention has a housing 1 in which a circuit board 4 on which an electronic circuit is formed is accommodated.
In the configuration example shown in FIG. 1, the housing 1 is positioned on the side opposite to the component mounting surface of the circuit board 4 and the case 2 as a first case member positioned on the component mounting surface side of the circuit board 4. As will be described later, the circuit board 4 is formed in a storage space 5 formed by a base 3 as a second case member that is fastened to the case 2 as will be described later, and is defined between the case 2 and the base 3. It is to be stored.

In the embodiment of the present invention, the case 2 and the base 3 are respectively formed with a recess 2a and a recess 3a, and a fastening flange 2b and a fastening flange 3b are extended outwardly at the respective peripheral portions. It has become.
In particular, a bent piece 2c is extended at the end of the fastening flange 2b of the case 2 so as to be orthogonal to the case 2 side, and the case 2 and the base 3 are fastened by screws as will be described later. In this case, the end of the fastening flange 3b of the base 3 comes into contact.

Further, screw holes 6a and 6b are formed in both fastening flanges 2b and 3b at appropriate intervals, the screw 7 is inserted from the case 2 side, and the nut 8 is screwed outside the base 3. The case 2 and the base 3 are fastened together.
The screw 7 is externally provided with a spacer 9 formed in a hollow cylindrical shape between the fastening flange 2b of the case 2 and the fastening flange 3b of the base 3. Note that the spacer 9 is not necessarily required, and a structure without the spacer may be used.
The fastening flanges 2b and 3b in the embodiment of the present invention hold the circuit board 4 between the screw holes 6a and 6b and the recesses 2a and 3a as described later, so that an appropriate distance is secured. Yes.

The peripheral edge of the circuit board 4 is positioned between the fastening flanges 2b and 3b, and between the fastening flange 2b of the case 2 and the circuit board 4 and between the fastening flange 3b of the base 3 and the circuit. An elastic body 10 is interposed between the circuit board 4 and the circuit board 4. The circuit board 4 is sandwiched between the case 2 and the base 3 through the elastic body 10. .

In the embodiment of the present invention, the elastic body 10 is applied to the case 2 and the base 3 and cured. Specifically, the elastic body 10 is preferably made of, for example, rubber or plastic.
In this configuration, the axial length of the spacer 9 described above in the longitudinal axis direction (vertical direction in FIG. 1) is set to be approximately equal to the total thickness of the circuit board 4 and the elastic body 10. It has become.

Next, a procedure for attaching the circuit board 4 when assembling the electronic apparatus S having such a configuration will be described.
First, the elastic body 10 is applied to a predetermined portion of the fastening flanges 2b and 3b where the vicinity of the end portion of the circuit board 4 is located and cured. For the application of the elastic body 10, for example, it is preferable to use a dispenser (not shown).

Next, the circuit board 4 is mounted on the elastic body 10 on the base 3 side coated and cured as described above so that the vicinity of the end of the circuit board 4 is positioned, and the spacer 9 is positioned at the screw hole 6b. And the case 2 is covered with the circuit board 4 and the base 3 so that the screw hole 6a of the case 2 matches the position of the screw hole 6b of the base 3. Then, the screw 7 is inserted from the screw hole 6a on the case 2 side, the spacer 9 is inserted, the end portion is protruded to the outside on the base 3 side, and the nut 8 is screwed together, whereby the circuit board 4 is elasticated 10. In this state, the case 2 and the base 3 are fastened together with the case 2 and the base 3 interposed therebetween.

Therefore, in this configuration, unlike the conventional case, the force due to the fastening of the case 2 and the base 3 by the screw 7 does not act directly on the circuit board 4 but acts via the elastic body 10. The stress generated in the substrate 4 is remarkably suppressed as compared with the conventional one, and therefore, the peeling of the solder and the crack due to the stress are prevented, and a highly reliable electronic device is provided as compared with the conventional one. Will be.

Next, a second configuration example will be described with reference to FIG.
The same components as those shown in FIG. 1 are denoted by the same reference numerals, detailed description thereof is omitted, and different points will be mainly described below.
In the second configuration example, the configuration after assembly is basically the same as the first configuration example, but the assembly procedure is different as described below.
That is, first, the elastic body 10 is applied to a portion located on the corresponding fastening flange 2b, 3b on either surface of the circuit board 4, that is, either the case 2 side or the base 3 side. Harden. In the first configuration example, the fastening flange 2b of the case 2 or the fastening flange 3b of the base 3 located on the surface opposite to the surface of the circuit board 4 provided with the elastic body 10 has been described. Similarly, the elastic body 10 is applied and cured. The elastic body 10 does not necessarily have to be provided on both surfaces of the circuit board 4 as described above, and may have a structure provided on any one surface.

Next, according to the procedure described in the first configuration example shown in FIG. 1, the circuit board 4 is placed on the base 3 so that the vicinity of the end of the circuit board 4 is positioned on the fastening flange 3 b of the base 3. At the same time, the spacer 9 is positioned at a predetermined portion, the case 2 is covered, and screwing is performed.
As a result, like the first configuration example, the circuit board 4 is sandwiched between the case 2 and the base 3 via the elastic body 10.

Next, a third configuration example will be described with reference to FIG.
The same components as those shown in FIG. 1 are denoted by the same reference numerals, detailed description thereof is omitted, and different points will be mainly described below.
In this third configuration example, instead of applying the elastic body 10 in the first configuration example shown in FIG. 1, a thin plate-like elastic body 11 formed in advance in a thin plate shape is applied to each of the case 2 and the base 3. The adhesive 12 is used for sticking. If the adhesive 12 is conductive or uses a semiconductive material, the circuit board 4, the thin elastic plate 11, the case 2, and the base 3 can be at the same potential. This is preferable because the EMC characteristic due to the electromagnetic shielding effect is improved.
Except for the point that the adhesive 12 is used in this way, it is basically the same as the first configuration example shown in FIG. 1, and therefore detailed description thereof will be omitted here.

Next, a fourth configuration example will be described with reference to FIG.
The same components as those shown in FIG. 1 or FIG. 3 are denoted by the same reference numerals, detailed description thereof is omitted, and different points will be mainly described below.
The fourth configuration example is that the thin plate-like elastic body 11 in the third configuration example shown in FIG. 3 is adhered to the peripheral portion of the circuit board 4 facing the case 2 and the base 3 with an adhesive 12. This is different from the third configuration example.
Except for this point, the configuration is the same as that of the third configuration example, and detailed description thereof is omitted here.

Next, a fifth configuration example will be described with reference to FIG.
The same components as those of the first component shown in FIG. 1 are denoted by the same reference numerals, detailed description thereof is omitted, and different points will be mainly described below.
In the fifth configuration example, the peripheral portion of the circuit board 4 is covered with the semi-tubular elastic body 13.

That is, the semi-tubular elastic body 13 is formed, for example, by cutting an elastic body formed in a tube shape along the longitudinal axis direction, and has a peripheral edge so as to cover the end surface of the circuit board 4. The part is covered. In this case, the role of the conventional sealing member 55 (see FIG. 8) can also be used. Moreover, even if it is a case where it coat | covers partially, without covering over the perimeter, the stress suppression effect is fully expectable.
Except for the point using such a semi-tubular elastic body 13, it is basically the same as the configuration example shown in FIG. 1, and therefore detailed description thereof is omitted here.

Next, a sixth configuration example will be described with reference to FIG.
The same components as those of the first component shown in FIG. 1 are denoted by the same reference numerals, detailed description thereof is omitted, and different points will be mainly described below.
In the sixth configuration example, an O-ring-shaped elastic body 14 formed in an O-ring shape is attached to the peripheral portion of the circuit board 4.
For example, when the circuit board 4 has a rectangular plate shape as a whole, the O-ring-shaped elastic body 14 is preferably provided on two edges facing each other in parallel.

Further, in the sixth configuration example, the coupling flange 2b of the case 2 and the coupling flange 3b of the base 3 are provided with grooves 15a and 15b into which the O-ring elastic bodies 14 are respectively fitted. The O-ring elastic body 14 is attached to the peripheral portion of the circuit board 4 so as to be fitted into the grooves 15a and 15b.
Except for the point using such an O-ring elastic body 14, it is the same as the first configuration example, and therefore detailed description thereof is omitted here.
1 to 6 described above, only one edge side of the circuit board 4 is illustrated for simplification of the drawing.
In any of the above-described configuration examples, the screw 7 and the nut 8 are used to fasten the case 2 and the base 3. However, the present invention is not necessarily limited to this. For example, a tapping screw is used. Anyway, it is good.

Next, examples of surface protection measures for nameplates and various seals attached to the outer surface of a housing such as an electronic device will be described with reference to FIG.
The electronic device casing 21 accommodates a circuit board (not shown) on which an electronic circuit is formed. In this example, the overall external shape is formed in a roughly rectangular parallelepiped shape, and an appropriate outer surface is appropriately formed. A rectangular name plate 22 on which the model of the device is written is attached to the part.

On one surface 21a of the housing 1 to which the name plate 22 is attached, protection bars 23a to 23c are provided so as to be parallel to the three sides of the surface 21a.
The protective bars 23a to 23c are provided in the vicinity of the respective edges of the surface 21a, and the thickness thereof is set slightly larger than the thickness of the nameplate 22. The protection bars 23a to 23c in the embodiment of the present invention are formed in a generally semi-cylindrical shape. The overall shape of the protection bars 23a to 23c is not necessarily limited to the semi-cylindrical shape as described above, but may be other shapes such as a prismatic shape.

Since such protective bars 23a to 23c are provided, even if another identical casing (not shown) is stacked on the surface 21a to which the name plate 22 is adhered, the name plates are protected by the protective bars 23a to 23c. 22 and a housing (not shown) stacked on the top 22 are not in direct contact with each other, and a minute gap is secured. Therefore, unlike the conventional case, it is possible to prevent the nameplate 22 from being rubbed by the casing 1 placed thereon, and the description content becoming unclear or peeling off.

It can be applied to electronic devices that require longer soldering life and improved reliability on circuit boards.

Claims (4)

A circuit board on which an electronic circuit is formed;
An electronic device comprising a housing for storing the circuit board,
The housing includes a first case member and a second case member, and the first and second case members are each formed with a fastening flange for fastening to each other. By being screwed in the fastening flange, the first and second case members are fastened and the circuit board can be housed inside,
The circuit board has a peripheral portion positioned between the fastening flanges, and an elastic body is interposed between the peripheral portion of the circuit board and the fastening flange. An electronic device characterized in that the electronic device is sandwiched by a fastening flange via the elastic body. Between the fastening flange of the first case member and the fastening flange of the second case member, a spacer having a hollow portion formed so that a screw can be inserted is disposed, and the spacer is a peripheral edge of the circuit board. The thickness of the elastic member interposed between the fastening flange of the first case member and the circuit board, and the fastening flange of the second case member and the circuit board. 2. The electronic device according to claim 1, wherein the electronic device has an axial length corresponding to a total thickness of elastic bodies interposed therebetween. The electronic device according to claim 1, wherein the elastic body is provided so that a peripheral edge portion of the circuit board is encapsulated. The elastic body formed in an O-ring shape is attached to the peripheral portion of the circuit board, and the elastic body has a portion on the fastening flange side of the first case member and a portion on the fastening flange side of the second case member. 3. The method according to claim 1, wherein the first and second case members are inserted into grooves respectively recessed in the fastening flange of the first case member and the fastening flange of the second case member. Electronic equipment.

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