JP2006351698A - Printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printed wiring board capable of preventing durability of electric appliances from being deteriorated owing to stress applied to a screwed and fixed portion. <P>SOLUTION: A slit 1d is provided between a screwing hole 1a and an electric circuit 1b. In accordance with the printed wiring board 1 constructed as above, even if stress is applied to four corners when the printed wiring board 1 is clamped at four corners with screws, it is possible to prevent the stress from being transmitted to the electric circuit 1b because the stress is blocked by the slit 1d. Particularly, if the slit 1d is constructed such that arrows are extended from the center of the screw hole 1a radially toward both ends of the slit 1d within a range to avoid the electric circuit 1b, then even if the stress is transmitted as indicated by the arrows, it is prevented from being transmitted to the electric circuit 1b. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a printed wiring board that is screwed and fixed on a pedestal, and is suitable for use in a printed wiring board of an automobile controller.

  As a form of fixing the printed wiring board to the case or the like, a form in which the printed wiring board is accommodated in a slot provided in the case or the like and the entrance side of the slot is covered with a cover, or a form in which the four corners of the printed wiring board are screwed and fixed and so on.

  The former fixed form is applied, for example, to a type in which a connector is provided on an end face of a printed wiring board. In the case of this type, a connector such as another component can be fitted into the connector provided on the printed wiring board from the side of the printed wiring board. For this reason, the printed wiring board is accommodated in a slot or the like provided in the case, the window corresponding to the connector is provided in the cover, and the cover is fixed to the case, thereby fixing the printed wiring board while exposing the connector. Is possible.

  The latter fixing form is applied to, for example, a type in which a connector is provided on the surface of a printed wiring board, and a connector such as another component is inserted into the connector from the vertical direction of the printed wiring board. In the case of this type, connectors such as other components are inserted from the vertical direction of the printed wiring board, so that the printed wiring board cannot be accommodated in the slot provided in the case or the like as in the former case.

For this reason, screw holes are formed in the four corners of the printed wiring board, the four corners of the printed wiring board are placed on a pedestal provided in the case, and the four corners of the printed wiring board are fastened to the pedestal through the screw holes with screws. Thus, the printed wiring board is fixed to a case or the like (see, for example, Patent Document 1).
Japanese Utility Model Publication No. 5-411169

  However, when it is set as the fixed form which fastens the four corners of a printed wiring board with a screw, the stress by screwing will be added to the four corners of a printed wiring board. In particular, when the height of the pedestal is shifted due to a manufacturing error or when the surface of the pedestal is inclined, the applied stress becomes large. The electrical circuit section provided on the printed wiring board is laid out so as to avoid the four corners to be screwed, but the stress applied to the four corners also affects the electrical circuit section, and the electrical components in the electrical circuit section or electrical This causes a problem of deteriorating the durability of an electrical device in which the printed wiring board is used, such as destruction of a connection part (soldering or the like).

  In view of the above points, the present invention prevents the durability of an electrical device from deteriorating due to a stress applied to a portion fixed by screwing on a printed wiring board fixed to a case or the like by screwing. With the goal.

  In order to achieve the above object, according to the first aspect of the present invention, a screw (1) is formed through a screw hole (1a) provided in at least a part of the four corners of the quadrangle. 3) A printed wiring board configured to be fixed to the pedestal (2a) by 3), wherein the board (1) is provided with an electric component inside the screw hole (1a). (1b) and a slit (1d) penetrating the front and back of the substrate (1) between the screw hole (1a) and the electric circuit portion (1b). Yes.

  According to such a configuration, when the four corners of the printed wiring board are fastened by the screws (3), even if stress is applied to the four corners, the stress is blocked by the slit (1d), and the electric circuit portion ( It can be prevented from being transmitted to 1b). In particular, as shown in claim 2, when the slit (1d) extends radially from the center of the screw hole (1a) toward both ends of the slit (1d), the arrow indicates the electric circuit portion. If it is formed in a range that goes to the outside of (1b), even if the stress is transmitted as shown by an arrow, it can be prevented from being transmitted to the electric circuit portion (1b).

  Therefore, it is possible to prevent the durability of the electric device from being deteriorated due to the stress applied to the site fixed with screws.

  The invention according to claim 3 is characterized in that the slit (1d) has an arc shape with a larger radius than the screw head (3a) in the screw (3).

  Thus, if the slit (1d) has an arc shape, the area required to satisfy the above range, that is, the electric circuit portion (1b), compared to the case where the slit (1d) is linear, is obtained. It becomes possible to reduce the area of the portion that cannot be formed. Therefore, the area ratio of the electric circuit portion (1b) per area of the printed wiring board can be increased.

  In the invention according to claim 4, the board (1) is provided with an electric circuit portion (1 b) provided with electrical components inside the screw fastening hole (1 a), and the screw fastening hole (1 a). ) Is configured to have a portion having a radius larger than the radius of the screw head (3a) and a portion smaller than the radius of the screw head (3a) in the screw (3). A part of (1a) facing the electric circuit part (1a) is a part having a radius larger than the radius of the screw head (3a).

  According to such a configuration, when the four corners of the printed wiring board are fastened with the screws (3), even if stress is applied to the four corners, the stress is applied to the screw head (3a) in the screw fastening hole (1a). ), And is prevented from being transmitted to the electric circuit portion (1b). Thereby, the same effect as that of claim 1 can be obtained.

  In the invention according to claim 5, a portion of the screw fastening hole (1a) that is smaller than the radius of the screw head (3a) faces the electric circuit portion (1a) of the screw fastening hole (1a). It is characterized by two projecting portions (1e) projecting symmetrically from both sides of the portion.

  In this way, if the two projecting portions (1e) projected in contrast constitute a portion of the screw fastening hole (1a) that is smaller than the radius of the screw head (3a), stress bias is prevented more. For example, it is possible to prevent stress from remaining on the pedestal (2a) side.

  In the invention according to claim 6, a portion of the screw fastening hole (1a) having a radius larger than the radius of the screw head (3a) is formed in the screw fastening hole (1a) toward both ends of this portion. When the arrow is drawn radially from the center, the arrow is formed in a range that faces outward from the electric circuit portion (1b). Thereby, the same effect as that of claim 2 can be obtained.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
A first embodiment of the present invention will be described. FIG. 1 shows a top view of a printed wiring board 1 to which the first embodiment of the present invention is applied, and FIG. 2 shows a state where the printed wiring board 1 shown in FIG. A schematic diagram is shown. The printed wiring board 1 shown in these drawings is used for, for example, a junction block constituting an automobile controller. Hereinafter, the printed wiring board 1 of the present embodiment will be described with reference to these drawings.

  As shown in FIG. 1, the printed wiring board 1 is configured by a square such as a square or a rectangle with rounded corners. Screw holes 1a are formed at the four corners of the printed wiring board 1, and an electric circuit portion 1b is provided on the front surface (and the back surface) of the printed wiring board 1 so as to avoid the four corners.

  The screw hole 1a is circular, and its diameter is smaller than the diameter of the screw head 3a in the screw 3 shown in FIG. 2, and is equal to or slightly larger than the diameter of the screw groove (shaft) 3b. It has been enlarged.

  The electric circuit portion 1 b is provided inside the printed wiring board 1 with respect to the screw hole 1 a. The electric circuit portion 1b includes various electric components, and a desired electric circuit is configured by connecting the electric components via the pattern wiring formed on the printed wiring board 1. The electrical circuit portion 1b is provided with a connector 1c for electrically connecting the electrical circuit with other components. The connector 1c is provided on the surface of the printed wiring board 1, and is configured so that a connector (not shown) that is electrically connected to other components can be connected from the vertical direction of the printed wiring board 1. It has become.

  Other components and the like are fixed to the front surface and the back surface of the printed wiring board 1 as indicated by broken lines in FIG. Then, the connector that is electrically connected to other components and the like is integrated with the other components and the like, and together with the other components and the like, is fitted into the connector 1c from the vertical direction of the printed wiring board 1, thereby the electric circuit. It is configured to be electrically connected to the part 1b.

  Although not shown here, for example, a connector is also provided on one side of the printed wiring board 1, and the electric circuit portion 1b and other components in the printed wiring board 1 are connected to the outside through wires connected to the connector. Electrically connected. The other components described above are fixed to such a printed wiring board 1 and integrated together with the case 2, whereby an electric device including the printed wiring board 1 is configured.

  Further, in the present embodiment, slits 1d penetrating the front and back of the printed wiring board 1 are provided at each of the four corners of the printed wiring board 1 so as to partition the screw fastening hole 1a and the electric circuit portion 1b. It has been.

  FIG. 3 shows an enlarged view of one of the four corners of the printed wiring board 1. As shown in this figure, when the slit 1d extends radially from the center of the screw hole 1a toward both ends of the slit 1d, the arrow is directed outward from the electric circuit portion 1b. It is formed to be in a range that avoids the portion 1b (range that does not overlap). Specifically, the slit 1d is formed in a substantially arc shape having a radius equal to or greater than the radius of the screw head 3a.

  According to the printed wiring board 1 configured as described above, when the four corners of the printed wiring board 1 are fastened by the screws 3, even if stress is applied to the four corners, the stress is blocked by the slit 1d. It is possible to prevent transmission to the electric circuit portion 1b. In particular, when the slit 1d extends radially from the center of the screw hole 1a toward both ends of the slit 1d, the arrow is formed in a range that avoids the electric circuit portion 1b. Therefore, even if the stress is transmitted as indicated by an arrow, it can be prevented from being transmitted to the electric circuit portion 1b.

  Therefore, it is possible to prevent the durability of the electric device from being deteriorated due to the stress applied to the site fixed with screws.

  In the present embodiment, the slit 1d has an arc shape. For this reason, compared with the case where the slit 1d is linear, it is possible to reduce the area required to satisfy the above range, that is, the area where the electric circuit portion 1b cannot be formed. Therefore, the area ratio of the electric circuit portion 1b per area of the printed wiring board 1 can be increased.

  For reference, an example of the size of each part in the printed wiring board 1 of the present embodiment is shown. If the screw head 3a has a diameter of 6 mm, the slit 1d has a radius of about 7 mm from the center of the screw hole 1a. When the slit 1d is not provided as in the prior art, it has been confirmed that the electric circuit portion 1b must be separated from the center of the screw hole 1a by, for example, 10 mm or more in order to be able to relieve stress. For this reason, in the case of this embodiment, compared with the conventional case, it becomes possible to shorten the distance which should be separated from the electric circuit part 1b from the center of the screwing hole 1a.

  The slit 1d is formed by changing the shape of the molding die when forming the printed wiring board 1 or by performing NC processing for drilling a desired place with a pin. It is possible.

(Second Embodiment)
A second embodiment of the present invention will be described. In the present embodiment, the screw hole 1a is shaped like the combination of the screw hole 1a described in the first embodiment and the slit 1d, so that the same effect as in the first embodiment is obtained. Since the other structures are the same, only different parts will be described.

  FIG. 4 is an enlarged view of one of the four corners of the printed wiring board 1. As shown in this figure, the screwing hole 1a is basically constituted by a radius larger than the radius of the screw head 3a in the screw 3, and a part smaller than the radius of the screw head 3a is partially formed. The shape is provided.

  A portion of the screw hole 1a that is smaller than the radius of the screw head 3a is constituted by two projecting portions 1e. The two protrusions 1e are formed at symmetrical positions in the screw fastening hole 1a. Specifically, if the part facing the electric circuit part 1b of the screwing hole 1a is a part made larger than the radius of the screw head 3a, two projecting parts 1e are provided on both sides thereof. Yes. For example, when a diagonal line is drawn from the four corners of the printed wiring board 1, straight lines that bisect the angles of the four corners from the four corners of the printed wiring board 1 (equally divide at 45 °). When a straight line is drawn, two projecting portions 1e are provided on both sides centered on the straight line. The printed wiring board 1 is fixed to the case 2 by sandwiching the two protruding portions 1e between the screw head 3a and the base 2a.

  When the portion of the screw hole 1a that is larger than the radius of the screw head 3a adjacent to the electric circuit portion 1b extends radially from the center of the screw hole 1a toward both ends of the portion, The arrow is formed in a range that avoids the electric circuit portion 1b. For this reason, even if the stress is transmitted as shown by the arrow, it can be prevented from being transmitted to the electric circuit portion 1b.

  According to the printed wiring board 1 configured as described above, when the four corners of the printed wiring board 1 are fastened by the screws 3, even if stress is applied to the four corners, the stress is generated in the screw holes 1a. It can be blocked by the portion having a larger radius than the screw head 3a and transmitted to the electric circuit portion 1b. Thereby, the effect similar to 1st Embodiment can be acquired.

  Moreover, the part fastened with the screw | thread 3 is made into the two protrusion parts 1e arrange | positioned symmetrically. The two projecting portions 1e do not need to be symmetrical if they are simply sandwiched between the screw 3 and the base 2a. However, by arranging the two projecting portions 1e in this way, it becomes possible to prevent the stress from being biased more. For example, it is possible to prevent the stress from remaining on the pedestal 2a side. Become.

  As an example, when showing an example of the size of each part in the printed wiring board 1 of the present embodiment, the screw head 3a has a diameter of 6 mm, and the portion of the screwing hole 1a that has a larger radius than the screw head 3a is 3.5 mm to 4 mm. Thus, the distance that must be separated from the electrical circuit portion 1b from the center of the screwing hole 1a can be shortened more than in the first embodiment.

(Other embodiments)
In the first and second embodiments, the case where all four corners of the printed wiring board 1 are fastened with the screws 3 has been described. However, all the four corners are not necessarily required. For example, the present invention can also be applied to a case where only three of the four corners are fastened with screws 3. In this case, the slit 1d shown in the first embodiment or the screw hole 1a having the shape shown in the second embodiment may be provided only in the four corners that are fastened with the screws 3. However, if these are provided at all four corners, the printed wiring board 1 has a vertically and horizontally symmetrical shape, so that the printed wiring board 1 can be easily handled.

It is a figure which shows the cross-sectional structure of the printed wiring board 1 in 1st Embodiment of this invention. FIG. 2 is a schematic diagram when the printed wiring board 1 shown in FIG. 1 is fixed to a pedestal 2 a of a case 2. It is one enlarged view of the four corners of the printed wiring board 1 shown in FIG. It is one enlarged view of the four corners of the printed wiring board 1 in 2nd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Printed wiring board (board | substrate), 1a ... Screw hole, 1b ... Electric circuit part, 1c ... Connector, 1d ... Slit, 1e ... Projection part, 2 ... Case, 2a ... Base, 3 ... Screw, 3a ... Screw head 3b: Screw groove portion.

Claims (6)

It is configured as a rectangular substrate (1), and is configured to be fixed to the pedestal (2a) with screws (3) through screw fastening holes (1a) provided in at least a part of the four corners of the rectangle. A printed wiring board,
The board (1) is provided with an electric circuit part (1b) provided with electric components inside the screwing hole (1a), and the screwing hole (1a) and the electric circuit. A printed wiring board comprising a slit (1d) penetrating the front and back of the substrate (1) between the portion (1b). When the slit (1d) is drawn radially from the center of the screw hole (1a) toward both ends of the slit (1d), the arrow is directed outward from the electric circuit portion (1b). The printed wiring board according to claim 1, wherein the printed wiring board is formed in a wide range. The printed wiring board according to claim 1 or 2, wherein the slit (1d) has an arc shape having a larger radius than the screw head (3a) of the screw (3). It is configured as a rectangular substrate (1), and is configured to be fixed to the pedestal (2a) with screws (3) through screw fastening holes (1a) provided in at least a part of the four corners of the rectangle. A printed wiring board,
The board (1) is provided with an electric circuit part (1b) provided with electric components inside the screw hole (1a),
The screw hole (1a) has a portion having a radius larger than the radius of the screw head (3a) in the screw (3) and a portion smaller than the radius of the screw head (3a). Configured
The portion of the screw hole (1a) facing the electric circuit portion (1a) is a portion having a radius larger than the radius of the screw head (3a). Printed wiring board. A portion of the screw hole (1a) smaller than the radius of the screw head (3a) is symmetrical from both sides of the portion of the screw hole (1a) facing the electric circuit part (1a). 5. The printed wiring board according to claim 4, wherein the printed wiring board has two projecting portions (1 e) projecting into the printed circuit board. A portion of the screw hole (1a) having a radius larger than the radius of the screw head (3a) is provided with arrows radially from the center of the screw hole (1a) toward both ends of this portion. 6. The printed wiring board according to claim 4, wherein the printed wiring board is formed in a range in which the arrow is directed outward from the electric circuit portion (1 b) when pulled.

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