JP2014239105A - Mounting structure between power supply circuit board and chassis - Google Patents

Abstract

The present invention provides a mounting structure between a power circuit board and a chassis, which has good workability at the time of mounting and can obtain a strong fixing strength of a certain level or more in the mounted state. A chassis includes a bottom plate portion and a side plate portion that rises in an L shape from an end portion of the bottom plate portion. A power circuit board 22 having a circuit element 20 mounted on a printed board 18 is provided. The power circuit board 22 is attached to the inside of the chassis 30 so that the printed board 18 and the bottom plate portion 10 face each other. An end portion of the printed circuit board 18 is inserted and sandwiched between a first support piece 32 cut and raised part of the side plate part 12 and a second support piece 34 cut and raised part of the bottom plate part 10, and the bottom plate part 10 in the vertical direction. [Selection] Figure 1

Description

  The present invention relates to a mounting structure of a power supply circuit board having a circuit element mounted on a printed board and a chassis.

  Conventionally, as one form of the power supply device, a substantially rectangular bottom plate portion 10 and a chassis 16 having two side plate portions 12 and 14 erected in an L shape from the end of the bottom plate portion 10, and a substantially rectangular printed board 18 are provided. And a power circuit board 22 having circuit elements 20 mounted on the upper and lower surfaces. As shown in FIG. 4, the power circuit board 22 is placed inside the chassis 16 so that the printed circuit board 18 and the bottom plate portion 10 face each other. There is a power supply 24 attached. The material of the chassis 16 is a metal such as aluminum.

  When this type of power supply device is installed inside an electronic device (load), a specific surface of the chassis is brought into contact with the wall surface of the housing of the electronic device and is fixed with a screw or the like. That is, the chassis serves as a mounting portion when installed in an electronic device. Therefore, from the user's side, the larger the number of chassis surfaces, the greater the number of mounting direction options, which is convenient. However, since the power circuit board includes a power semiconductor, a transformer, and the like having a large power loss in the internal circuit elements, it is not preferable that the surroundings are surrounded by the chassis because heat is trapped.

  Therefore, the chassis 16 of the power supply device 24 is a chassis composed of three surfaces (the bottom plate portion 10 and the side plate portions 12 and 14) perpendicular to each other in consideration of ease of attachment to the electronic device and ventilation with respect to the circuit elements. Yes. In addition, a circuit element having a large power loss is mounted on a portion where the chassis 16 on the upper surface side of the printed board 18 is widely open.

  Conventionally, as a mounting structure between the power circuit board 22 and the chassis 16, for example, as shown in FIG. 5, a caulking nut 25 is press-fitted into the bottom plate portion 10, and the printed board 18 is fixed to the upper end surface of the caulking nut 25 with screws 26. There was a mounting structure. The caulking nut 25 functions as a spacer that prevents the wiring pattern on the lower surface of the printed circuit board 18 and the circuit element 20 from contacting the bottom plate portion 10.

  Further, the DC stabilized power supply device disclosed in Patent Document 1 has a mounting structure (FIG. 2 disclosed in Patent Document 1) in which a bottom plate portion is cut and raised to form a horizontal plane, and a printed circuit board is fixed to the horizontal plane with screws. 25). Further, the side plate portion is processed to form two claw pieces substantially parallel to the bottom plate portion, and an end portion of the printed circuit board is inserted therebetween to support the mounting structure (reference numeral 62 in FIG. 2 disclosed in Patent Document 1). Or 63). Furthermore, the end portion of the bottom plate portion is erected, a notch substantially parallel to the bottom plate portion is provided in the standing portion, and a printed circuit board is inserted into and supported by the notch (reference numeral 27 of FIG. 2 disclosed in Patent Document 1). have.

JP 2000-287448 A

  In the structure for attaching the power supply circuit board 22 and the chassis 16, it is important that the attaching operation is easy and that sufficient fixing strength (vibration resistance, impact resistance) is obtained after the attachment. Since the power supply circuit board 22 is usually mounted with large and heavy circuit elements such as a transformer and a copper bar for wiring, a plurality of places on the printed circuit board 18 are fixed to the chassis 16 in order to ensure sufficient fixing strength. There is a need. Therefore, it is required that a structure in which as many of the plurality of places as possible are easy to attach.

  In the case of the conventional mounting structure shown in FIG. 5, the printed circuit board 18 is fixed to the chassis 16 via a solid structure (caulking nut 25), and a high strength is obtained. However, since the structure involves a troublesome work of press-fitting the caulking nut 25 into the chassis 16 and further tightening the screws 26, not only the member cost but also the labor cost is increased.

  In the case of the mounting structure indicated by reference numeral 25 in Patent Document 1, the caulking nut is omitted, and the printed circuit board is fixed to the horizontal plane from which the bottom plate portion is cut and raised, so that a fixed strength is obtained. However, the troublesome work of screw tightening is required.

  In the case of the mounting structure indicated by reference numerals 62 and 63 in Patent Document 1, since both the caulking nut 25 and the screw 26 are omitted, the mounting operation is relatively easy. However, since the printed circuit board 18 is supported between two thin claw pieces extending from the side plate portion, particularly when vibration in the vertical direction is applied to the bottom plate portion, the base end portion of the claw piece is applied. There is a risk of stress concentration and deformation or damage. Therefore, the strength for fixing the printed circuit board 18 is weaker than the two mounting structures fixed with screws. And since the space | interval of a printed circuit board and a baseplate part is short, the nail | claw piece of the one near a baseplate part cannot be made too thick.

  Similarly, in the case of the mounting structure denoted by reference numeral 27, the mounting operation is relatively easy. However, when vibration is applied, the end of the bottom plate portion may be raised and the portion provided with the cut may be deformed or damaged. In addition, if the part to be raised is enlarged and made into a shape that is difficult to deform, when the chassis is formed by punching from a standard metal plate, the outer shape of the chassis developed on a flat surface will spread outward, so Inefficiencies can increase chassis costs.

  Since a large and heavy circuit element is mounted on the power circuit board as described above, it is difficult not to use fixing with screws at all in order to obtain a sufficient fixing strength after being attached to the chassis. However, in order to reduce the total man-hours for mounting, there is a demand to reduce the number of troublesome screw tightening etc. as much as possible, and the printed circuit board is supported or fixed by a part of the chassis, and a predetermined fixing strength can be obtained. A new mounting structure was required.

  The present invention has been made in view of the above-described background art, and provides a mounting structure between a power supply circuit board and a chassis that has good workability during mounting and can obtain a fixed strength of a certain level or more in the mounted state. With the goal.

  The present invention comprises a chassis having a bottom plate portion and a side plate portion standing in an L shape from an end portion of the bottom plate portion, and a power circuit board on which a circuit element is mounted on a printed board, and the printed board is the bottom plate. A power supply circuit board and chassis mounting structure that is mounted in a direction opposite to the first part, wherein the printed board has a first support piece obtained by cutting and raising a part of the side plate part and a part of the bottom plate part This is a structure for mounting the power supply circuit board and the chassis, which is inserted and sandwiched between the second support piece cut and raised, and is positioned in the vertical direction with respect to the bottom plate portion.

  The first support piece is provided at a position closer to the side plate portion than the second support piece, and an end portion of the printed board can be inserted from an oblique direction with respect to the bottom plate portion. Can do.

  Further, the chassis is integrally formed by punching from a metal plate, the side plate portion has a heat radiating surface and a bent portion, and the heat radiating surface is provided in a portion of the side plate portion on the tip side from the printed board, The lower end portion continues to the end portion of the bottom plate portion by the bent portion formed so as to escape the end portion of the printed circuit board, and the specific circuit element mounted on the printed circuit board is fixed to the heat dissipation surface. Thus, a structure in which heat is dissipated by heat conduction can be obtained.

  In the mounting structure of the power circuit board and the chassis according to the present invention, the end portion of the printed circuit board is sandwiched between a part of the side plate part (first support piece) and a part of the bottom plate part (second support piece). It is a structure positioned in the vertical direction. Therefore, it can be easily attached by inserting the printed circuit board from the side, and a troublesome screw tightening operation is unnecessary. In addition, by appropriately adjusting the size and shape of the first support piece and the second support piece, a printed circuit board can be used rather than a conventional mounting structure that is not screwed (for example, a structure sandwiched between two thin nail pieces). The fixing strength can be increased.

It is the perspective view (a) and side view (b) which show 1st embodiment of the attachment structure of the power circuit board and chassis of this invention. It is the side view (a) which shows the modification of 1st embodiment, and the side view (b) which shows another modification. It is the perspective view (a), side view (b), and sectional view (c) which show 2nd embodiment of the attachment structure of the power circuit board and chassis of this invention. FIG. 3 is a perspective view (a) showing an external appearance of a general power supply device, a perspective view (b) explaining a power circuit board, and a perspective view (c) explaining a chassis. It is the perspective view (a) and side view (b) which show the attachment structure of the conventional power supply circuit board and a chassis.

  Hereinafter, a first embodiment of a mounting structure of a power circuit board and a chassis according to the present invention will be described with reference to FIG. Here, the same configurations as those of the above-described power supply device 24 having the conventional mounting structure are denoted by the same reference numerals and description thereof is omitted.

  A power supply device 28 having the mounting structure of the first embodiment includes a substantially rectangular bottom plate portion 10 and a metal chassis 30 having two side plate portions 12 and 14 erected in an L shape from the end portion of the bottom plate portion 10. The power circuit board 22 is the same as described above, and the assembled appearance is as shown in FIG. Here, the chassis 30 is formed by punching a metal plate such as aluminum.

  As shown in FIG. 1A, the side plate portion 12 of the chassis 30 is provided with a first support piece 32 by cutting and raising a side end portion on the opposite side to the side plate portion 14. In the first support piece 32, a portion from the base end portion (boundary portion with the bottom plate portion 10) of the first side plate portion 12 to the vicinity of the center is cut and raised in an L shape inward, and a tip portion 32a thereof is a bottom plate portion. 10 extends substantially vertically.

  The bottom plate portion 10 is provided with a second support piece 34 by cutting and raising a side end corresponding to the first support piece 32. The second support piece 34 is bent inward at a predetermined length inward from the boundary with the first side plate 12, and the tip 34 a extends substantially perpendicularly from the bottom plate 10.

  Then, as shown in FIG. 1B, the first and second support pieces 32, 34 are opposed to each other with their tip portions 32 a, 34 a separated by a distance approximately equal to the plate thickness of the printed circuit board 18.

  When the power circuit board 22 is attached, the end of the printed circuit board 18 is inserted from the side between the tip 32a and the tip 34a. By this operation, the inserted portion is positioned in the vertical direction with respect to the bottom plate portion 10. Positioning so that the printed circuit board 18 is not removed after being inserted is performed by screwing or the like at locations other than the first and second support pieces 34 and 34.

  As described above, in the mounting structure of the power circuit board and the chassis according to the first embodiment, the end portion of the printed circuit board 18 is a part of the side plate part 12 (first support piece 32) and a part of the bottom plate part 10 ( The structure is sandwiched between the second support piece 34) and positioned in the vertical direction. Therefore, it can be easily attached by inserting the printed circuit board 18 from the side, and a troublesome screw tightening operation is unnecessary.

  As can be seen from FIG. 1 (b), each support piece 32, 34 has a cut and raised depth (height to be cut inward or length from the base end) that is not much relative to the thickness of the chassis 30. Since it is not deep, it hardly deforms even if some external force is applied. For example, if the chassis 30 is an aluminum plate having a thickness of 1 mm, the depth at which the upper side and the second support piece 34 are raised may be about 2 to 10 mm.

  Since the support pieces 32 and 34 are in contact with the printed circuit board 18 because the end faces of the tip portions 32a and 34a are secured, the contact area of the tip portions 32a and 34a is reduced while securing the fixing strength by the support pieces 32 and 34. Is possible. Therefore, the mounting space of the circuit element 20 (and the wiring pattern) on the printed board 18 can be widened.

  As shown in FIG. 2A, the first and second support pieces 34 and 34 have a structure in which the distal end portion 32a of the first support piece 32 is disposed on the side plate more than the distal end portion 34a of the second support piece 34. It may be provided near the portion 12 so that the end of the printed circuit board 18 can be inserted into the bottom plate portion 10 from an oblique direction. According to this mounting structure, the mounting operation can be performed more smoothly, and the fixing strength in the mounted state is not significantly reduced.

  As another modification, as shown in FIG. 2B, the first support piece 36 is cut and raised like the second support piece 34, and the second support piece 38 is changed to the first support piece 32. The printed board 18 may be inserted and positioned between the first and second support pieces 36 and 38. According to this mounting structure, the end portion of the printed circuit board 18 is firmly sandwiched and supported by the wide surfaces of the support pieces 36 and 38, which is particularly advantageous when the outer shape of the printed circuit board 18 is large.

  Next, a second embodiment of the power supply circuit board and chassis mounting structure of the present invention will be described with reference to FIG. Here, the same configurations as those of the power supply devices 24 and 28 are denoted by the same reference numerals, and description thereof is omitted.

  The power supply device 36 having the mounting structure of the second embodiment includes a substantially rectangular bottom plate portion 10 and a metal chassis 38 having two side plate portions 12 and 14 erected in an L shape from the end portion of the bottom plate portion 10. The power supply circuit board 22 is the same as described above. Here, the chassis 38 is formed by punching a metal plate such as aluminum.

  As shown in FIG. 3A, the side plate portion 12 of the chassis 38 has a heat radiating surface 12a and a bent portion 12b. The heat radiating surface 12 a is a flat portion on the front end side of the printed circuit board 18 of the side plate portion 12, and is disposed substantially perpendicularly to the bottom plate portion 10 at a position entering the inside of the end portion of the printed circuit board 18. . The lower end portion of the heat radiating surface 12a is continuous with the bent portion 12b bent outward so as to escape the end portion of the printed circuit board 18, and the end portion on the opposite side of the bent portion 12b is continuous with the end portion of the bottom plate portion 10. Yes.

  The bent portion 12b has a side end opposite to the side plate portion 14 cut inwardly, and is provided with a first support piece 40 (1) continuous from the lower end portion of the heat radiation surface 12a. The first support piece 40 (1) has a tip portion 40 a (1) extending substantially vertically toward the bottom plate portion 10.

  The bottom plate portion 10 is provided with a second support piece 42 (1) by cutting and raising a side end corresponding to the first support piece 40 (1). The second support piece 42 (1) is bent inward at a predetermined length inward from the end on the first side plate 12 side of the bottom plate portion 10, and its tip end 42 a (1) is bent from the bottom plate portion 10. It extends almost vertically.

  As shown in FIG. 3B, the first and second support pieces 40 (1) and 42 (1) are arranged so that their front end portions 40a (1) and 42a (1) Opposite distances are approximately equal to the thickness. Here, similarly to the modification shown in FIG. 2A, the distal end portion 40a (1) is provided at a position closer to the bent portion 12b than the distal end portion 42a (1).

  The first and second support pieces 40 (2), 42 having substantially the same shape as the first and second support pieces 40 (1), 42 (1) are also located slightly closer to the side plate part 14 from the center of the side plate part 12. (2) is provided, and the distal end portion 40a (2) and the distal end portion 42a (2) face each other.

  In the power supply circuit board 22, a specific circuit element 20 a that requires heat dissipation is mounted at a position inside the end of the printed circuit board 18. The circuit element 20a is, for example, a power semiconductor, and has a plate-like main body in which a semiconductor chip is resin-molded. Lead terminals protruding from the lower end of the circuit element 20a are solder-connected to the through holes of the printed circuit board 18, and the printed circuit board It stands up substantially perpendicular to 18.

  When attaching the power circuit board 22, the end of the printed circuit board 18 is placed between the tip 40a (1) and the tip 42a (1) and between the tip 40a (2) and the tip 42a (2). The base plate 10 is inserted from an oblique direction. With this operation, the two inserted parts are positioned in the direction perpendicular to the bottom plate part 10. Positioning that prevents the printed board 18 from being removed after inserting the printed circuit board 18 is performed by tightening screws at locations other than the first and second support pieces 40 (1), 42 (1), 40 (2), and 42 (2). Is done by.

  Next, the circuit element 20a is fixed in contact with the heat radiation surface 12a. Here, a structure in which the heat generated by the circuit element 20a is conducted and dissipated to the heat radiating surface 12a by firmly fixing the plate-like body of the circuit element 20a to the heat radiating surface 12a via the insulating sheet 44 having good thermal conductivity. I have to. The method of fixing the circuit element 20a to the heat radiating surface 12a is arbitrary. For example, the circuit element 20a may be fixed using a metal fitting such as an elastic clip, or may be bonded and fixed using a heat radiating sealant or the like.

  As described above, the mounting structure between the power circuit board and the chassis of the second embodiment can obtain the same effects as those of the first embodiment. Further, the circuit element 20a disposed on the inner side of the end portion of the printed circuit board 18 can also dissipate heat using the chassis 38, so that it is not necessary to attach independent heat radiation fins to the circuit element 20a. Further, since the chassis heat can be radiated without forcibly arranging the circuit element 20a at the end portion of the printed circuit board 18, the degree of freedom in the layout design of the entire circuit element 20 and the layout design of the wiring pattern is increased.

  In addition, the attachment structure of the power supply circuit board and chassis of this invention is not limited to the said embodiment. For example, in the above-described embodiment, the mounting structure of the invention is provided in one side plate portion 12 and the bottom plate portion 10 of the chassis 30, 38, but provided in the other side plate portion 14 and the bottom plate portion 10. It is also possible. If attachment work is easy, it may be provided in any number of places.

  In the power supply devices 28 and 36, the upper surface side of the power supply circuit board 22 is exposed from the opening portions of the chassis 30 and 38, but the chassis 30 and 38 are not touched by a maintenance worker of the electronic device. You may attach the cover member which covers the opening part. In this case, it is preferable to provide a ventilation hole in the cover member so that heat does not accumulate inside.

  If it is not necessary to radiate heat from the circuit element in the chassis, the material of the chassis may be replaced with another material such as a synthetic resin from metal. In addition, the size and shape of the portion where the first and second support pieces contact the printed circuit board can be appropriately changed according to the size of the printed circuit board, the weight of the circuit element to be mounted, and the like.

DESCRIPTION OF SYMBOLS 10 Bottom plate part 12, 14 Side plate part 12a Heat radiation surface 12b Bending part 18 Printed circuit board 20 Circuit element 20a Circuit element (power semiconductor)
22 power supply circuit boards 28, 36 power supply devices 30, 38 chassis 32, 40 (1), 40 (2) first support pieces 32a, 40a (1), 40 (2) tip portions 34, 42 (1), 42 ( 2) Second support piece 34a, 42a (1), 42 (2) tip

Claims (3)

A chassis having a bottom plate portion and a side plate portion standing in an L shape from an end portion of the bottom plate portion, and a power circuit board on which a circuit element is mounted on the printed board, the printed board faces the bottom plate portion. In the mounting structure of the power circuit board and the chassis that are mounted in the direction,
An end portion of the printed circuit board is inserted and sandwiched between a first support piece obtained by cutting and raising a part of the side plate part and a second support piece obtained by cutting and raising a part of the bottom plate part. Mounting structure of power supply circuit board and chassis where vertical positioning is performed.   The said 1st support piece is provided in the position near the said side board part rather than the said 2nd support piece, The edge part of the said printed circuit board can be inserted from the diagonal direction with respect to the said baseplate part. Mounting structure of power supply circuit board and chassis. The chassis is integrally formed by punching from a metal plate,
The side plate portion has a heat radiating surface and a bent portion, and the heat radiating surface is provided at a portion of the side plate portion on the front end side of the printed circuit board, and a lower end portion thereof is formed so as to escape the end portion of the printed circuit board. Continued to the end of the bottom plate portion by the bent portion,
The power circuit board and chassis mounting structure according to claim 1 or 2, wherein the specific circuit element mounted on the printed board is fixed to the heat dissipation surface and radiated by heat conduction.

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