JP2013207290A - Electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic apparatus enabling highly precise attachment of a circuit board to a case body.SOLUTION: In an electronic apparatus, a case body 30 includes a flange 33 supporting a bottom face of a circuit board 10, a flange peripheral wall 35 extending upward from the flange, protrusions 37 and 38 protruding from the flange peripheral wall 35 and restricting a position of a side face of a circuit board 10 supported by a flange part 33, and a recess 39 formed between roots of the bottoms 37 and 38 and the flange 33.

Description

  The present invention relates to an electronic device, and more particularly to an electronic device in which a circuit board on which an electronic component is mounted is accommodated in a case and covered with a cover.

  2. Description of the Related Art There is known an electronic apparatus including a circuit board on which electronic components are mounted, a case main body that accommodates the circuit board, and a cover that covers an opening of the case main body.

  For example, Patent Document 1 discloses an electronic control device in which a cover formed of a conductive material is fixed to a case (case body) with screws through which through holes formed at four corners of a printed circuit board (circuit board) are inserted. Electronic equipment).

JP-A-8-148842

  However, in the structure of Patent Document 1, the printed circuit board is placed on the shelf at the four corners of the case and positioned by the side peripheral wall of the case, but there is a gap between the side surface of the printed circuit board and the side peripheral wall of the case. There is. For this reason, positional displacement may occur between the through hole and the screw hole of the printed board, and workability is poor when the printed board and the cover are fixed to the case with screws.

  In view of the above points, an object of the present invention is to provide an electronic device capable of positioning a circuit board on a case body with high accuracy.

  The present invention is an electronic apparatus having a circuit board on which electronic components and connectors are mounted, a case main body that houses the circuit board, and a cover that covers an opening of the case main body, and the case main body includes the circuit board A substrate support seat that supports the bottom surface of the circuit board, a support seat side wall that extends from the substrate support seat toward the cover, and a side surface position of the circuit board that protrudes from the support seat side wall and is supported by the substrate support seat. It is characterized by comprising a convex part to be regulated and a concave part formed between the base of the convex part and the substrate support seat.

  According to the present invention, the circuit board supported by the board support seat is positioned by the convex portion whose side surface protrudes from the side wall of the support seat. Therefore, compared with the conventional case where the circuit board is positioned on the entire inner peripheral surface of the side wall of the board case, the circuit board can be made with high accuracy by positioning only the inner surface of the convex portion with high accuracy. Can be positioned.

  Furthermore, since the concave portion is formed at the base of the convex portion, the case body is formed by forging or casting, and unnecessary portions such as burrs are formed at the base of the convex portion, which is rounded. However, this roundness and the circuit board do not interfere with each other. Therefore, it becomes possible to support the circuit board without floating on the board support seat.

  In the present invention, the case body is provided with notches in the board support seat and the support seat side wall in order to arrange the connector, and the convex portions are formed on both sides of the notch. Is preferred.

  In this case, since the convex portions are formed on both sides of the notch, it is possible to reinforce the case body by causing the convex portions to function as reinforcing ribs as well as the function of positioning the circuit board.

  Moreover, in this invention, it is preferable that the said cover is arrange | positioned above the said convex part, and the top surface of the said convex part is parallel to the upper surface of the said board | substrate support seat.

  In this case, even if the cover is deformed so as to bend downward due to a downward external force, the cover comes into contact with the top surface of the convex portion, and deformation of the cover is suppressed. Therefore, even when the electronic component is mounted on the upper surface of the circuit board, it is possible to reliably prevent the electronic component from being damaged due to the contact of the cover.

  In the present invention, it is preferable that the convex portion includes a tapered surface inclined from the top surface to the circuit board side from the side wall side of the substrate support seat between the top surface and the concave portion.

  In this case, since the convex portion has a tapered surface, the circuit board can be smoothly placed on the substrate support seat without being caught by the convex portion.

1 is a perspective view showing an electronic apparatus according to an embodiment of the present invention. A case main body is shown, (a) is a top view, (b) is a perspective view. The expansion perspective view near a rib. 4A and 4B are cross-sectional views taken along the line IV-IV in FIG. 1, in which FIG. 1A shows a state where no external force is present, and FIG.

  An electronic apparatus according to an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, an electronic device 100 according to the present embodiment is an electronic control unit (ECU), for example, and includes a housing case 20 that is a housing that houses a circuit board 10 (see FIG. 2). Yes. The housing case 20 includes a case body 30 and a cover 40 that covers the opening of the case body 30. The circuit board 10 positioned and supported by the case body 30 is fastened together with the cover 40 by screws 50 and fixed to the case body 30.

  In the description of the present embodiment, for the sake of convenience, the direction along the front and back surfaces of the circuit board 10 accommodated in the case main body 30 will be described as the horizontal direction, and the direction orthogonal to the front and back surfaces of the circuit board 10 will be described as the vertical direction. However, the posture in which electronic device 100 is actually attached varies depending on the installation location.

  In addition to the connector 11, electronic components (not shown) are mounted on the circuit board 10 and a wiring pattern is formed. Examples of the electronic component include an IC chip, a transistor, a diode, and a capacitor. The electronic component is mounted on the front surface, the back surface, or the front and back surfaces of the circuit board 10. The circuit board 10 has through holes at four corners (see FIG. 2A).

  The case main body 30 and the cover 40 are formed by using a metal having high thermal conductivity, such as aluminum, copper, stainless steel, and iron, by using an appropriate processing method such as pressing, cutting, welding, or die casting. Yes. The case body 30 is preferably formed by die casting, and the cover 40 is formed by pressing a sheet metal.

  As shown in FIGS. 2A and 2B, the case main body 30 has a substantially rectangular (rectangular) bottom wall 31 in plan view, and upwards (from the peripheral edge of the bottom wall 31 toward the cover 40). Side wall 32 extending in the direction of the side), and has a substantially rectangular parallelepiped box shape with the upper part opened as a whole. However, a cutout is formed in the side wall 32 of the case body 30 at a portion corresponding to the connector 11. Thereby, the connector 11 is exposed from the electronic device 100, and the connector 11 and an external harness (not shown) can be connected.

  A horizontal flange portion 33 is formed over the upper portion of each side wall 32, and the upper surface of the flange portion 33 serves as a substrate support surface for placing and supporting the circuit board 10. The flange portion 33 corresponds to the substrate support seat of the present invention. Screw holes 34 corresponding to the through holes of the circuit board 10 are formed at the four corners of the flange portion 33.

  Further, a flange peripheral wall 35 rises upward from the outer peripheral end of the flange portion 33. The inner surface of the flange peripheral wall 35 is formed to have substantially the same shape as the outer surface of the cover 40 in plan view, and the cover 40 is positioned by the flange peripheral wall 35. The flange peripheral wall 35 corresponds to the support seat side wall of the present invention. A notch is also formed in the flange portion 33 and the flange peripheral wall 35 on one long side of the case body 30 at a portion corresponding to the connector 11 of the circuit board 10.

  The case main body 30 has a bulging portion 36 in which a through hole is formed in order to attach the electronic device 100 to another device (not shown) with a bolt or the like.

  A convex portion 37 that protrudes inward and extends upward from the flange portion 33 is formed integrally with the case main body 30 on the flange peripheral wall 35 of the case main body 30. The convex portion 37 has a function of positioning the circuit board 10 supported by the flange portion 33 with its inner side surface 37a (see FIGS. 3 and 4A) contacting the side surface of the circuit board 10. Here, two convex portions 37 are provided on the flange peripheral wall 35 on the long side where the notch of the case main body 30 is not formed, and one on each of the flange peripheral walls 35 on both short sides of the case main body 30, for a total of four. Is formed.

  Further, the flange peripheral walls 35 at both end portions of the cutout of the case body 30 are each formed integrally with the case body 30 so as to protrude inward and extend upward from the flange portion 33. . The convex portion 38 also has a function of positioning the circuit board 10 supported by the flange portion 33 with the inner side surface thereof coming into contact with the side surface of the circuit board 10.

  In addition, as shown in FIG. 3, a recess 39 is formed between the root of the protrusion 37 and the flange portion 33.

  And the convex part 37 has the taper surface 37c which inclines toward the circuit board 10 side (inward) side from the flange part 33 side between the top surface 37b and the recessed part 39. FIG. Here, the inner side of the top surface 37b is chamfered to form a tapered surface 37c. Further, the top surface 37 b of the convex portion 37 is parallel to the upper surface of the flange portion 33, that is, is horizontal.

  Although not shown in detail, the convex portion 38 is also formed with a concave portion, has a tapered surface, and the top surface is horizontal, like the convex portion 37.

  As shown in FIG. 1, the cover 40 has a substantially quadrangular shape (rectangular shape) in plan view, and the four corners are recessed to form flange portions 41, and one through hole 42 is formed in each flange portion 41. Has been. These through holes 42 correspond to the screw holes 34 of the case body 30. Since the four corners of the cover 40 are recessed, and the screw head 51 of the screw 50 is positioned in the recessed flange portion 41, the screw head 51 does not protrude from the upper surface of the cover 40.

  Hereinafter, a method for assembling the electronic device 100 will be described.

  First, the circuit board 10 is temporarily supported on the case body 30. Specifically, the circuit board 10 is lowered from the opening side of the case body 30 and placed on the upper surface of the flange portion 33. At this time, the side surface of the circuit board 10 is positioned in contact with the inner side surface 37 a of the convex portion 37 and the inner side surface of the convex portion 38.

  Next, the cover 40 is temporarily supported on the case body 30. Specifically, the cover 40 is placed on the circuit board 10 temporarily supported by the case body 30. At this time, the cover 40 is positioned by the flange peripheral wall 35 of the case body 30.

  Next, the screw 50 is inserted through the through hole of the circuit board 10 and the through hole 42 of the cover 40 and screwed into the screw hole 34 of the case body 30. Thereby, the circuit board 10 and the cover 40 are fixed to the case main body 30, and the assembly of the electronic device 100 is completed.

  As described above, the side surface of the circuit board 10 is positioned in contact with the inner side surface 37 a of the convex portion 37 and the inner side surface of the convex portion 38. Therefore, as compared with the conventional case where the circuit board 10 is positioned on the entire inner peripheral surface of the flange peripheral wall 35, the circuit board 10 can be obtained by positioning only the inner surfaces of the convex portions 37 and 38 with high accuracy. Can be positioned with high accuracy.

  Since the convex portions 37 and 38 are formed with the tapered surface 37c, the circuit board 10 can be smoothly placed on the flange portion 33 without being caught by the convex portions 37 and 38. Therefore, the workability of placing and positioning the circuit board 10 on the flange portion 33 of the case main body 30 is improved.

  Further, since the circuit board 10 is positioned with high accuracy and placed on the flange portion 33, the alignment of each through hole of the circuit board 10 and the screw hole 34 corresponding to these through holes is reliably performed. Therefore, when the screw 50 is screwed into the screw hole 34, the screw 50 can be surely inserted through the through hole of the circuit board 10, and the workability of the screw tightening process is improved.

  Further, as shown in FIG. 3, a concave portion 39 is formed between the root of the convex portion 37 and the flange portion 33. As a result, the case body 30 is formed by forging or casting, and an unnecessary portion such as a burr is formed at the base of the convex portion 37. Even when the round portion is rounded, the roundness and the circuit board 10 interfere with each other. Never do. Therefore, the circuit board 10 can be supported without lifting from the flange portion 33.

  The convex portions 37 and 38 also function as ribs, and the case main body 30 can be reinforced.

  By the way, as shown in FIG. 4A, the cover 40 is disposed above the convex portions 37 and 38 with a gap therebetween. Therefore, when the cover 40 is deformed by a downward external force, if the electronic component 12 is mounted on the upper surface of the circuit board 10, the electronic component 12 and the cover 40 may come into contact with each other and the electronic component 12 may be damaged. is there.

  However, since the top surface 37b of the convex portions 37 and 38 is horizontal, even if an external force is applied and the cover 40 is deformed, the cover 40 comes into contact with the top surface 37b of the convex portion 37 and the deformation of the cover 40 is suppressed. Is done. Therefore, it is possible to reliably prevent the cover 40 from coming into contact with the electronic component 12 mounted on the upper surface of the circuit board 10.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to this. For example, the case where the flange portion 33 and the flange peripheral wall 35 corresponding to the substrate support seat and the support seat side wall of the present invention are formed over the entire circumference excluding the notch for the connector 11 has been described. However, the substrate support seat and the support seat side wall of the present invention are not necessarily formed over the entire circumference, and may be formed partially or intermittently.

  Further, the case where the four all side surfaces of the circuit board 10 are positioned by the convex portions 37 and 38 has been described. However, only some of the four side surfaces of the circuit board 10 may be positioned by the convex portions 37 and 38.

  DESCRIPTION OF SYMBOLS 10 ... Circuit board 11 ... Connector 12 ... Electronic component 20 ... Housing case 30 ... Case main body 31 ... Bottom wall 32 ... Side wall 33 ... Flange part 34 ... Screw hole 35 ... Flange peripheral wall 37 38 ... convex portion, 37a ... inner surface, 37b ... top surface, 37c ... tapered surface, 39 ... concave portion, 40 ... cover, 41 ... flange portion, 42 ... through hole, 50 ... screw, 100 ... electronic device.

Claims (4)

An electronic device having a circuit board on which an electronic component and a connector are mounted, a case main body that houses the circuit board, and a cover that covers an opening of the case main body,
The case body is
A board support seat for supporting the bottom surface of the circuit board;
A support seat side wall extending from the substrate support seat toward the cover;
A protrusion that protrudes from the side wall of the support seat and regulates the position of the side surface of the circuit board supported by the substrate support seat;
An electronic apparatus comprising: a concave portion formed between a base of the convex portion and the substrate support seat.   The case body has a notch formed in the substrate support seat and the support seat side wall in order to arrange the connector, and the convex portions are formed on both sides of the notch. The electronic device according to claim 1.   The electronic device according to claim 1, wherein the cover is disposed above the convex portion, and a top surface of the convex portion is parallel to an upper surface of the substrate support seat.   The electronic device according to claim 3, wherein the convex portion includes a tapered surface that is inclined from the top surface to the circuit board side between the top surface and the concave portion.

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