JP2009049160A - Power supply - Google Patents

Abstract

Provided is a power supply device that can be stably fixed to a circuit board without rattling, without touching an electronic component, and having high long-term reliability.
A circuit board 14 on which an electronic component 12 is mounted in advance and a box-shaped case 16 for housing the circuit board 14 are provided. The case 16 includes at least a pair of side plates 20 and 22 that face each other, and each side plate 20 and 22 includes an opening 26 at a position spaced apart from the top plate 18 of the case 16 by a predetermined distance. A plurality of openings 26 are formed in at least one of the side plates 20 and 22, and each opening 26 is located on the same plane. The locking pieces 30 extend integrally with the side plates 20 and 22 in the respective openings 26, and the end surfaces 38 and 40 of the circuit board 14 that are opposed to each other are positioned so as to engage with the respective openings 26 of the side plates 20 and 22. A protrusion 42 is provided. The protrusion 42 is inserted from the inside of the case into the opening 26 of the side plates 20 and 22, and is sandwiched between the locking piece 30 and the inner peripheral surface facing it in the opening 26.
[Selection] Figure 1

Description

  The present invention relates to a small-sized power supply device including a case that covers a circuit board and electronic components mounted thereon.

  Conventionally, as a structure for attaching a shielding case to a power supply circuit board on which electronic components are mounted in advance, there has been a structure as shown in FIG. 5, for example. The power supply device 50 includes a circuit board 52 and a case 56. The circuit board 52 is a rectangular printed wiring board made of, for example, a glass epoxy material or a ceramic material, on which an electronic component 54 is mounted, and has an input / output terminal (not shown) for interfacing with the printed board. The case 56 is a box-shaped case obtained by pressing a metal plate, and is formed in a so-called U-shape having one top plate and side plates positioned at right angles on both sides thereof. Substrate receiving portions 58a and 58b are bent toward the inside of the case at the side plate end portions of the case 56, and notches 60a and 60b and chamfers 62a and 62b, which will be described later, are formed in the substrate receiving portions 58a and 58b. ing.

  When the circuit board 52 is attached to the case 56, one end of the circuit board 52 is engaged with the notch 60a, and the other end is brought into contact with the chamfer 62b and pushed. As a result, the side plate of the case 56 spreads outward due to its own elasticity and the pushing force, and the circuit board 12 is accommodated in the notch 60b. At the same time, the force applied to the side plate of the case 56 is released. Return to the position. In this way, both ends of the circuit board 56 are locked to the notches 60a and 60b, and the mounting operation is completed.

In Patent Document 1, a locking piece is formed on the side wall of the shield case by punching, and after the circuit board is inserted inside the case, the locking piece is bent inward to fix the circuit board to the case. A method is disclosed.
Japanese Utility Model Publication No. 7-7192

  However, in the above-described conventional power supply device 50 mounting structure, since the conductive substrate receiving portion 58 protrudes to the inside of the circuit board 52, the electronic component 54 and the wiring pattern of the circuit board 52 are close to each other, and There is a problem that the insulation distance cannot be secured, which is a factor that hinders downsizing of the outer shape of the product. In addition, if the width d of the notches 60a and 60b is set to be large in consideration of the variation in the thickness of the base material of the circuit board 52, the circuit board 52 is wobbled in the height direction. Another work was needed. On the contrary, if the notch width d is set to be small so that the circuit board 52 is press-fitted and fixed in the notch, a mechanical force such as unpredictable twist is applied to the circuit board 52, and the electronic components in the circuit board And the long-term reliability of the mounted solder may be reduced.

  Further, in the method disclosed in Patent Document 1, the conductive locking piece that protrudes to the inside of the circuit board is a hindrance for securing a predetermined insulation distance. In addition, since it is a caulking structure that fixes the circuit board by bending the locking piece on the case side wall, there is a risk that mechanical stress such as unpredictable twisting may be applied to the electronic components in the circuit board or the mounting solder. there were. Furthermore, there was a problem that a separate facility such as a press for caulking the locking piece is required.

  The present invention has been made in view of the above-described problems of the background art, and provides a power supply device that can be stably fixed to a circuit board without rattling, without contacting the electronic component, and having high long-term reliability. For the purpose.

  The present invention is a power supply device including a circuit board on which electronic components are mounted in advance and a box-shaped case for storing the circuit board, the case including at least a pair of side plates facing each other, and each side plate Are provided with openings at positions spaced apart from the top plate of the case by a predetermined distance, and a plurality of openings are formed on at least one side plate so that the openings are on the same plane. The side plate is integrally extended with a locking piece, and the circuit board is formed with protrusions on the opposite end surfaces of the circuit board at positions that engage with the openings of the case side plate. The opening of the case side plate is inserted from the inside of the case, is sandwiched between the locking piece and the inner peripheral surface facing the locking piece in the opening, and the case and the circuit board are mutually connected by the elastic force of the locking piece. Position A power supply device to be.

  The opening of the case side plate is formed slightly larger than the cross-sectional shape in the thickness direction of the protrusion of the circuit board, and a locking piece extending in the opposite direction from the top plate side of the case is formed in each opening. The width of the protrusion formed on the circuit board is longer than the width of the locking piece in the same direction.

  The force for pushing the protrusion in the circuit board surface direction by the locking piece is weaker than the force for holding the circuit board end face by the pair of side plates.

  The positions of the protrusions on the circuit board are provided symmetrically with respect to the intersection of the diagonal lines of the circuit board surface, and the positions of the locking pieces of the case side plate are points with respect to the intersection of the diagonal lines of the case top plate. It is provided symmetrically.

  According to the power supply device of the present invention, the case portion holding the circuit board is not in a form protruding toward the inside of the circuit board, so that the clearance between the case part and the electronic component mounted on the circuit board is not reduced, Hard to touch. Moreover, even if the case is a conductive metal plate, the insulation distance from the electronic component or circuit pattern is not shortened, and a predetermined insulation property can be ensured. As a result, the outer shape of the product can be reduced. . Furthermore, the circuit board is clamped at a predetermined position of the case by the elastic restoring force of the locking piece, and is fixed without rattling. Therefore, the circuit board is easily and accurately positioned and fixed with an adhesive. No other special equipment is required. In addition, there is no caulking or the like by a press machine in fixing the position of the case, and the circuit board has a structure in which force is applied in a fixed direction, for example, inside and below the case by the elasticity of the case locking piece. The circuit board is not subjected to an unexpected mechanical force such as twisting, and there is no possibility that the long-term reliability of the electronic components in the circuit board and the mounting solder thereof will be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 show an embodiment of the present invention. A power supply device 10 according to this embodiment includes a circuit board 14 in which an electronic component 12 is mounted in advance on a so-called printed board, and an electronic component 12 on the circuit board 14. A box-shaped case 16 that covers the mounted surface 14a is provided.

  The case 16 is a metal shield case, and is stamped by punching a thin metal plate. The case 16 is provided with a top plate 18 that is approximately the same size as the circuit board 14 and covers the circuit board 14. The top plate 18 has a rectangular shape that is long in one direction, and side plates 20 and 22 are continuously provided on a pair of long sides of the top plate 18. The side plates 20 and 22 are connected to the top plate 18 in the width direction and have the same length as the top plate 18, and the lengths in the connecting direction are equal to each other and shorter than the top plate 18. The side plates 20 and 22 are bent at a substantially right angle on the long side of the top plate 18 with respect to the top plate 18 and have a U-shaped cross section.

  The side plate 20 is integrally provided with surface mount terminals 24 that can be connected to a separate printed circuit board for mounting. In the portion of the side plate 20 close to the edge 20a, openings 26 are provided at two locations on both sides of the surface mounting terminal 24, respectively. As shown in FIG. 3, the opening 26 is a square having a long width in a direction parallel to the end edge 20 a, and the upper side 26 a on the side opposite to the end 20 a of the opening 26 has an upper side A pair of narrow slits 26c continuous from the center of the portion 26a toward the top plate 18 of the opening 26 are formed at a predetermined interval. Further, the side of the opening 26 close to the end edge 20a is a lower side portion 26b.

  Between the pair of slits 26 c formed in the upper side portion 26 a of the opening 26, a tongue-like locking piece 30 is provided from the upper end 28 toward the center of the opening 26. The locking piece 30 is formed in a quadrangular shape, and the tip end portion 30 a on the side opposite to the upper end edge portion 28 reaches the vicinity of the center of the long square of the opening 26. The locking piece 30 is formed by being left uncut when the opening 26 is punched from the side plate 20.

  Similarly, a pair of openings 26 are provided on the side plate 22 opposite to the side plate 20. Each opening 26 is provided with a locking piece 30. In the side plate 20 and the side plate 22, a pair of openings 26 are provided along the edge portions 20a and 22a in accordance with the positions of protrusions of the circuit board 14 to be described later.

  Side plates 32 and 34 are continuously provided on the pair of short sides of the top plate 18 of the case 16, respectively. The width directions of the side plates 32 and 34 connected to the top plate 18 are the same length as the top plate 18, and the lengths in the connecting direction are equal to each other and slightly shorter than the side plates 20 and 22. The side plates 32 and 34 are bent substantially at right angles to the top plate 18 at the short side of the top plate 18 and have a U-shaped cross section. A rectangular notch 36 is formed in the end edges 32a, 34a of the side plates 32, 34 on the opposite side of the top plate 18 in the center of the end edges 32a, 34a.

As shown in FIG. 4, the circuit board 14 to which the case 16 is attached has a rectangular shape, and protrusions 42 are provided at two positions on the end faces 38 and 40 which are a pair of long sides of the circuit board 14. The protrusion 42 is formed by being left uncut when the end surfaces 38 and 40 of the circuit board 14 are cut, and is formed in a trapezoidal shape with the end surfaces 38 and 40 as the bottom. The protruding length of the protrusion 42 from the end surfaces 38 and 40 is such that the tip portion slightly protrudes from the opening 26 in a state where the side plates 20 and 22 of the case 16 are in contact with the end surfaces 38 and 40 of the circuit board 14, respectively. is there. Further, the length parallel to the end faces 38 and 40 of the protrusion 42 is a length that can be fitted with a slight clearance inside the opening 26 of the case 16, and forms the locking piece 30. It is formed wider than the width between the slits 26c. The protrusion 42 fits into the opening 26 of the case 16 when the case 16 is attached to the circuit board 14. On the end surfaces 38 and 40, the positions of the pair of protrusions 42 positioned on opposite sides are provided at positions that are asymmetric with respect to the end surfaces 38 and 40.
Are different in the direction along.

  In addition, the thickness of the circuit board 14 can be fitted inside the opening 26 of the case 16. When the protrusion 42 of the circuit board 14 is fitted into the opening 26, the surface 14 a of the circuit board 14 is positioned above the tip part 30 a of the locking piece 30. At this time, the back surface 14 b of the front surface 14 a comes into contact with the lower side portion 26 b of the opening 26. A plurality of surface mount terminals 44 extending from the back surface 14 b of the circuit board 14 protrude from both short sides of the circuit board 14.

  Next, a method for assembling the power supply device 10 will be described. First, the circuit board 14 on which the electronic component 12 is mounted is placed inside the box-shaped case 16 so that the surface 14 a is inside the case 16. At this time, the circuit board 14 and the case 16 are set to be aligned so that the opening 26 and the protrusion 42 face each other. In this embodiment, the direction is determined so that the end surface 38 of the circuit board 14 faces the side plate 20 side of the case 16 and the end surface 40 faces the side plate 22 side. Next, the projection 42 of the circuit board 14 is inserted into one of the openings 26 of the side plates 20 and 22, and the other projection 42 of the circuit board 14 is stretched slightly outward by elastically deforming the side plates 20 and 22. Into the opening 26. When the protrusion 42 is fitted into the opening 26, the locking piece 30 is slightly pushed outward by the protrusion 42 to expand, and elastically abuts against the corner on the surface 14 a side of the protrusion 42. It is pressed against the lower side portion 26 b of the opening 26. As a result, the circuit board 14 is locked to the case 16 without rattling.

  Here, in a state where the locking piece 30 is elastically deformed and curved outward, the force that pushes the circuit board 14 in the surface direction is large enough that the side plates 20 and 22 are not elastically deformed outward. That is, the force with which the side plates 20 and 22 clamp the both end surfaces 38 and 40 of the circuit board 14 is set larger than the force with which the locking piece 30 pushes the protrusion 42.

  After the power supply device 10 is assembled, a predetermined circuit pattern is formed by the surface mounting terminals 24 and 44 and mounted on a mounting printed board on which electronic components are mounted.

  According to the case mounting structure 10 of this embodiment, since a part of the case 16 does not protrude to the inside of the circuit board 14, the clearance between the case 16 and the electronic component 12 mounted on the circuit board 14 is small. It is hard to touch each other. Even if the case 16 is a conductive metal plate, the insulation distance from the electronic component 12 and the circuit pattern is not shortened, and a predetermined insulation property can be ensured. As a result, the product outer shape can be reduced in size. It is. Further, since the circuit board 14 has a structure in which a force of a predetermined strength is applied toward the inside and the bottom of the case 16 by the elastic restoring force of the locking piece 30 of the case 16, the circuit board 14 has the structure 16 is fixed to a predetermined position accurately. Furthermore, there is no caulking operation by a press or the like when fixing the position, no mechanical force is applied to the circuit board 14, and there is no possibility that the long-term reliability of the electronic component 12 in the circuit board 14 or its mounting solder will be reduced. Furthermore, since the circuit board 14 is clamped at a predetermined position of the case 16 by the elastic force of the locking piece 30 and is fixed without rattling, another operation such as fixing with an adhesive or other special equipment is unnecessary. It is.

  In addition, the case mounting structure of this invention is not limited to the said embodiment, It can change suitably. The shape and number of openings and protrusions can be freely changed. Further, when the positions of the opening and the protrusion are formed point-symmetrically with respect to the intersection of the diagonal lines of the top plate or circuit board of the case, the case and the circuit board can be assembled even when the directions of the case and the circuit board are reversed. The shape of the protrusion on the circuit board may be a rectangular or arcuate protrusion in addition to the trapezoid, and a chamfer may be provided at the protruding corner or the corner with the end face of the circuit board. The strength of the spring of the locking piece can be changed depending on the shape and size of the locking piece, and the strength is such that the side plate does not open into a letter C. The material of the case can be changed freely according to its purpose.

It is a perspective view of the power supply device of one Embodiment of this invention. It is A surface sectional drawing of FIG. It is the front view (a) of the opening part of this embodiment, and BB sectional drawing (b) of (a). It is a top view of the circuit board of this embodiment. It is a front view of the power supply device of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Power supply device 12 Electronic component 14 Circuit board 16 Case 18 Top plate 20, 22, 32, 34 Side plate 26 Opening part 30 Locking piece 38, 40 End surface 42 Protrusion

Claims (4)

  In a power supply device including a circuit board on which electronic components are preliminarily mounted and a box-shaped case for storing the circuit board, the case includes at least a pair of side plates facing each other, and each side plate has a ceiling of the case. Each opening is provided at a position spaced apart from the plate by a plurality of openings, and a plurality of openings are formed on at least one side plate, and each opening is located on the same plane, and each opening is integrated with the side plate. A locking piece extends, and protrusions are formed on the opposing end surfaces of the circuit board at positions that engage with the openings of the case side plate, and the protrusions of the circuit board are openings of the case side plate. The case and the circuit board are positioned with respect to each other by the elastic force of the locking piece. The locking piece is sandwiched between the locking piece and the inner peripheral surface facing the locking piece in the opening. Switching control in accordance with.   The opening of the case side plate is formed slightly larger than the cross-sectional shape in the thickness direction of the protrusion of the circuit board, and each opening has a tongue-like engagement extending in the opposite direction from the top plate side of the case 2. The power supply device according to claim 1, wherein a piece is formed, and a width of the protrusion formed on the circuit board is longer than a width of the locking piece in the same direction.   3. The power supply device according to claim 2, wherein a force pushing the protrusion in the circuit board surface direction by the tongue piece is weaker than a force holding the circuit board end face by the pair of side plates. The positions of the protrusions of the circuit board are provided point-symmetrically with respect to the intersection of the diagonal lines of the circuit board surface, and the positions of the locking pieces of the case side plate are points with respect to the intersection of the diagonal lines of the case top plate. The power supply device according to claim 1, wherein the power supply device is provided symmetrically.

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