JP2009231472A - Electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic apparatus capable of preventing chips from entering a case when a screw is tightened. <P>SOLUTION: A circuit board 10 is secured to a lower case 20 using a first screw Sc1. A circuit board attaching pedestal 23 formed by drawing which protrudes toward the inside of the case is formed on a side edge. A first female thread 24b in which the first screw Sc1 is screwed is formed on the side of a throttled space S1 formed by drawing at the circuit board attaching pedestal 23. An attaching plate 25 having a second female thread 26b in which a second screw Sc2 is screwed is fixed to the side of the drawing space S1 in such a state that it is positioned at a side opening of the throttled space S1. The lower case 20 is secured to an upper case 30 using the second screw Sc2, and a through-hole 33 through which the second screw Sc2 screwed into the second female thread part 26b of the attaching plate 25 passes is formed at the side edge. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electronic device.

A housing structure in an electronic device is disclosed in, for example, Patent Document 1. In Patent Document 1, a housing for housing a circuit board is configured by a base member and a case, and a first tapping screw is inserted through a through-hole of the circuit board from the lower surface side of the circuit board to The circuit board is fixed in the case by being screwed into the female screw portion. Further, the case and the base member are fastened by screwing the second tapping screw from the outside of the case into the female screw portion of the mounting plate portion of the base member through the through hole of the case.
JP 2002-335084 A

  However, when the screw is tightened, chips enter the housing. Specifically, when the first tapping screw is inserted through the through hole of the circuit board and screwed into the female screw portion of the mounting portion of the case, the second tapping screw is screwed into the female screw portion of the mounting plate portion of the base member. When entering, chips are generated from the internal thread portion, and the chips remain in the housing.

  The present invention has been made under such a background, and an object of the present invention is to provide an electronic device that can prevent chips from entering a case when screws are fastened.

  In the first aspect of the present invention, a circuit board on which electronic components are mounted, a box shape having an upper surface opened, a lower case for housing the circuit board therein, and a box shape having a lower surface opened, In an electronic apparatus that is disposed on the lower case so as to close the opening of the lower case and includes an upper case for housing the circuit board together with the lower case, the lower case and the upper case One of the circuit boards is fastened with a first screw, and a circuit board mounting base is formed on the side edge by drawing to project inward of the case, and the circuit board mounting base in the circuit board mounting base A first female screw portion into which the first screw is screwed is provided on the drawing space side obtained by drawing, and a second female screw portion into which the second screw is screwed is provided on the drawing space side. The fastening plate material is The other one of the lower case and the upper case is fixed by a second screw, and the other one of the lower case and the upper case is fastened by the second screw. The gist is that a through hole through which the second screw threaded into the second female thread portion of the fastening plate member passes is formed.

  According to the first aspect of the present invention, for one of the lower case and the upper case, a circuit board mounting pedestal is formed on the side edge of the circuit board mounting base so as to protrude inward of the case. The first female screw portion is provided on the diaphragm space side obtained by the above, the first screw is screwed into the first female screw portion, and the circuit board is fastened. When this screw is tightened, chips are generated when the first screw is screwed into the first female thread portion, but the chips exit into the throttle space outside the case and do not enter the case.

  In addition, a through hole is formed in the side edge of the other of the lower case and the upper case, and the second screw is screwed into the second female thread portion of the fastening plate through the through hole and the lower case and the upper case are inserted. One side of the case is fastened. When this screw is tightened, chips are generated when the second screw is screwed into the second female thread portion of the fastening plate, but the chips come out in the throttle space outside the case, and inside the case not enter.

  ADVANTAGE OF THE INVENTION According to this invention, the chip at the time of screw fastening can prevent entering into a case inside.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
FIG. 1 is a perspective view of an electronic device 1 in the present embodiment. FIG. 2 is an exploded perspective view of the electronic device 1. FIG. 3 is a bottom view of the electronic device 1 of FIG. 4 is a front view of the electronic apparatus 1 of FIG. FIG. 5 is an exploded perspective view of the lower case 20 constituting the electronic device 1. 6 is an enlarged cross-sectional view of a main part taken along line AA in FIG.

Electronic device 1 in the present embodiment is an in-vehicle power converter (inverter).
In FIG. 2, the electronic device 1 includes a circuit board 10 and a case (housing) made of a metal plate, and the case includes a lower case 20 and an upper case 30. The lower case 20 is for housing the circuit board 10, and the upper case 30 is for housing the circuit board 10 together with the lower case 20 so that the side edge overlaps the side edge of the lower case 20. belongs to.

With respect to the circuit board 10, various electronic components (not shown) are mounted on the circuit board 10.
About the lower case 20, as shown in FIG. 5, the lower case 20 made of sheet metal has a box shape with an upper surface opened as an overall shape. Specifically, the side plate 22 extends upward from the outer peripheral edge of the rectangular bottom plate 21. A circuit board mounting base 23 is formed on the side edge by drawing to project inward of the case. The circuit board mounting base 23 is formed at the corners formed by the bottom plate 21 and the side plates 22 at the four corners of the rectangular bottom plate 21 and at the center of the long side. The circuit board mounting base 23 is narrowed down from the side surface and the bottom surface of the lower case 20, and the side surface and the bottom surface are thereby opened (opened). In the enlarged view of the formation place of the circuit board mounting base 23 shown in FIG. 6, the upper surface 23a of the circuit board mounting base 23 is a horizontal plane. The circuit board 10 is mounted on the upper surface 23 a of the circuit board mounting base 23. The circuit board mounting base 23 by drawing is formed by pressing the base plate into a die with a punch, and the punched portion becomes the drawing space S1 obtained by drawing.

  Further, a burring screw 24 is formed on the upper surface 23a of the circuit board mounting base 23 so as to protrude downward. That is, a cylindrical portion 24a protruding downward from the upper surface 23a of the circuit board mounting base 23 is formed by drawing, and a first female screw portion 24b is formed on the inner surface of the cylindrical portion 24a. As described above, the first female screw portion 24b is provided on the diaphragm space S1 side. Then, the first screw Sc1 is screwed into the burring screw 24 through the through hole 11 formed in the circuit board 10 from above the circuit board 10, and the circuit board 10 is fastened.

  As shown in FIG. 5, a mounting plate 25 as a fastening plate member is prepared so as to correspond to each circuit board mounting base 23. As shown in FIG. 6, this mounting plate 25 is a side opening of the aperture space S1. Is fixed to the side plate 22 of the lower case 20 by welding. A burring screw 26 is formed on the mounting plate 25 so as to protrude into the aperture space S1. That is, the cylindrical portion 26a protruding from the mounting plate 25 toward the drawing space S1 is formed by drawing, and the second female screw portion 26b is formed on the inner surface of the cylindrical portion 26a. As described above, the mounting plate 25 provided with the second female screw portion 26b into which the second screw Sc2 is screwed on the throttle space S1 side is fixed in a state of being positioned at the side opening of the throttle space S1.

  As for the upper case 30 in FIG. 2, the upper case 30 made of sheet metal has a box shape with the lower surface opened as an overall shape, and is disposed on the lower case 20 so as to close the opening of the lower case 20. Specifically, the side plate 32 extends downward from the outer peripheral edge of the rectangular ceiling plate 31. The side plate 32 is formed with a step 32a so as to spread outward at a position approaching the upper end of the side plate 22 of the lower case 20, and extends downward on the outer peripheral side of the side plate 22 of the lower case 20 (the side plate 22 of the lower case 20). Around).

  As shown in FIG. 6, a through-hole 33 through which the second screw Sc <b> 2 screwed into the second female screw portion 26 b of the mounting plate 25 passes is formed on the side edge of the upper case 30 (attachment at the side edge). A through hole 33 is formed at a position corresponding to the burring screw 26 of the plate 25). The second screw Sc <b> 2 is screwed into the burring screw 26 from the outside of the side surface of the upper case 30 through the through hole 33 of the upper case 30. Thereby, the upper case 30 is fastened to the lower case 20 by the second screw Sc2.

The electronic component mounted on the circuit board 10 is electrically connected to an external device via a wire via a connector (not shown).
Next, a method for assembling the electronic device 1 will be described.

  First, the circuit board 10, the lower case 20, and the upper case 30 on which electronic components are mounted are prepared. Then, the circuit board 10 is placed on the circuit board mounting base 23 of the lower case 20. Then, the first screw Sc1 is screwed into the burring screw 24 from above the circuit board 10 through the through hole 11 of the circuit board 10, and the circuit board 10 is fastened to the lower case 20 with the first screw Sc1. Chips generated when the first screw Sc1 is screwed into the first female screw portion 24b at the time of fastening the screw exit to the throttle space S1 outside the case and do not enter the case.

  Subsequently, the upper case 30 is placed over the lower case 20 so as to close the opening of the lower case 20. Then, the second screw Sc2 is screwed into the burring screw 26 from the side of the upper case 30 through the through hole 33 of the upper case 30, and the upper case 30 is fastened to the lower case 20 with the second screw Sc2. Chips generated when the second screw Sc2 is screwed into the second female screw portion 26b of the mounting plate 25 at the time of the screw tightening exit to the throttle space S1 outside the case and do not enter the case. .

According to the above embodiment, the following effects can be obtained.
(1) A circuit board mounting base 23 is formed on the lower case 20 by drawing, and the circuit board 10 is fastened to the circuit board mounting base 23 so that the first screw Sc1 protrudes into the aperture space S1. Further, the upper case 30 is fastened to the lower case 20 so that the second screw Sc2 protrudes into the throttle space S1. Therefore, it can prevent that the chip at the time of screw fastening enters in a case. Moreover, the fastening part of the lower case 20 and the upper case 30 is sheet metal, and does not sandwich the circuit board 10 having a different coefficient of thermal expansion. Therefore, when the lower case 20 and the upper case 30 are fastened with the circuit board 10 interposed therebetween, thermal stress is applied in the axial direction of the screw due to the difference in thermal expansion coefficient, so it is necessary to use a screw that is resistant to axial stress. There is. In contrast, in the present embodiment, the circuit board is not fastened (because there is no joint fastening), and there is a degree of freedom in selecting the screw.

The embodiment is not limited to the above, and may be embodied as follows, for example.
-Although the mounting plate 25 with a burring screw was fixed to the lower case 20 by welding, it may be carried out by caulking or the like other than welding.

  As shown in FIG. 6, the female thread portions (24b, 26b) are formed by the burring screws 24, 26, but instead of the burring screws 24, 26, as shown in FIG. That is, it may be changed to a weld nut (welding nut) or a press-fit nut. In this way, it is possible to fasten the screw with a stronger fastening force, which is effective when a stronger fastening force is required, such as a mounting position where the resonance vibration is severe, an environment where the screw is likely to be burdened, and the like.

  The circuit board mounting base 23 by drawing is provided in six places in FIG. 2 and the like, but is not limited thereto. Specifically, the lower case 20 is provided at a total of six locations at the four corners and the center of the long side, but may be provided at appropriate locations such as only four locations at the four corners.

  Although the circuit board mounting base 23 by drawing is provided in the lower case 20, the circuit board mounting base 23 by drawing may be formed on the upper case 30 and the circuit board 10 may be fastened to the upper case 30. .

  -Although it was a vehicle-mounted device, it is not limited to a vehicle-mounted device, but can be applied to electric devices in general.

FIG. 11 is a perspective view of an electronic device in this embodiment. FIG. The bottom view of an electronic device (A arrow line view of FIG. 1). The front view of an electronic device (B arrow view of FIG. 1). The disassembled perspective view of the lower case which comprises an electronic device. The principal part expanded sectional view in the AA line of FIG. The principal part expanded sectional view in another example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Circuit board, 20 ... Lower case, 23 ... Circuit board mounting base, 24 ... Burring screw, 24b ... First female screw part, 25 ... Mounting plate, 26 ... Burling screw, 26b ... Second female screw part, 30 ... Upper case, 40, 41 ... Nut, Sc1 ... First screw, Sc2 ... Second screw.

Claims (1)

A circuit board on which electronic components are mounted;
A box shape with an open top surface, a lower case for storing the circuit board inside,
In an electronic device comprising a box shape having an open bottom surface and disposed on the lower case so as to close the opening of the lower case, and an upper case for housing the circuit board together with the lower case ,
One of the lower case and the upper case is one in which the circuit board is fastened with a first screw, and a circuit board mounting base is formed on the side edge by drawing that protrudes inward of the case, A first female screw portion into which the first screw is screwed is provided on the drawing space side obtained by the drawing processing on the circuit board mounting base, and a second screw is screwed on the drawing space side. The fastening plate member provided with the second female screw portion is fixed in a state of being located at the side opening of the throttle space,
The other of the lower case and the upper case is such that one of the lower case and the upper case is fastened by the second screw, and the side edge is connected to the second female screw portion of the fastening plate member. An electronic device, wherein a through-hole through which the second screw to be screwed passes is formed.

Images