JPH09246765A - Heat radiating structure of board mounting type electric heat generating part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent soldering cracks, etc., in such a part that the lead of an electric heat generating part is soldered to a PC (printed wiring) board and an increase in installation space for the surface of the PC board when the electric heat generating part is to be subjected to be fitted to a heat sink. SOLUTION: In this heat radiating structure, an electric heat generating part 2 which generates a heat together with the use in a PC board is fitted vertically to the PC board 1 with a lead 3, and a heat sink 4 is secured to the part 2, then the heat sink 4 is provided with a main heat radiating part 4a being vertical against the board 1 and a fixing leg part 4b which is extended from the part 4a and formed smaller in width than the part 4a, and the part 4b is fixed to the board 1. Since the load of the electric heat generating part and heat sink is supported by the fixing leg part, soldering cracks can be prevented from generation in the soldered part of the lead. In addition, the fixing leg part is formed smaller, so that the installation space on the surface of the board may be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to heat dissipation of a board-mounted electric heat generating component in which an electric heat generating component that generates heat during use is mounted on a printed wiring board and a heat radiating plate that releases the heat of the electric heat generating component is attached. Regarding the structure.

[0002]

2. Description of the Related Art There are many electric components mounted on a printed wiring board that generate heat as they are used. For example,
Switching elements such as transistors, diodes, FETs, and thyristors used in the inverter lighting device of the lighting device generate heat due to the switching action during lighting of the lamp. Since such an electric heating component has a small heat radiation area, it is easy to raise the temperature, and there is a risk of early thermal deterioration.To prevent this, a radiator plate is attached to this kind of electric heating component, and through this radiator plate The structure that radiates heat is adopted.

FIG. 11 shows a conventional heat dissipation structure. In FIG. 11, reference numeral 61 is a printed wiring board (PC board), and 62 is an electric heating component mounted on the PC board 61 to generate heat with use, such as an inverter lighting device. The switching elements 63, ... Used are leads of the switching element 62. The leads 63 are inserted into the PC board 61 and soldered. Reference numeral 64 denotes a metal heat radiating plate, which is fixed to the switching element 62 by a mounting screw 65 while being in close contact with one side surface of the switching element 62. Therefore, when the switching element 62 generates heat, this heat is transmitted to the heat dissipation plate 64, and the switching element 6
It is emitted to the outside air from the surface of 2 itself and the surface of the heat dissipation plate 64. Therefore, the temperature rise of the switching element 62 is suppressed, and the thermal deterioration of the switching element 62 can be prevented.

In the case of the above structure, the load of the heat sink 64 and the switching element 62 is applied to the leads 63, so that stress is generated in the soldered portions of the leads 63. When the PC board 61 is repeatedly warped or deformed due to a change in ambient temperature, solder cracks or the like may be generated in the soldered portion on which the stress acts, causing electrical disconnection.

On the other hand, in the case of another conventional heat dissipation structure shown in FIG. 11, the lower end of the heat dissipation plate 70 is bent into an L shape to form a fixed seat portion 71, and the fixed seat portion 71 is closely attached to the PC board 61. And is fixed to the PC board 61 with a fixing screw 72. Then, the lead 6 of the switching element 62
3 is bent, and the switching element 62 itself is tilted down to be brought into close contact with the upper surface of the fixed seat portion 71.
Is fixed to the fixed seat portion 71 with a mounting screw 73.

In the case of such a structure, when the switching element 62 generates heat, this heat is transmitted to the heat dissipation plate 70 and is radiated to the outside air from the surface of the switching element 62 itself and the surface of the heat dissipation plate 70. Therefore, the temperature rise of the switching element 62 is suppressed, and the thermal deterioration of the switching element 62 can be prevented. Moreover, since the heat radiation plate 70 receives the load of the switching element 62 and the load of the heat radiation plate 70 is supported by the fixed seat portion 71, stress is not applied to the leads 63, and therefore, there is a concern that solder cracks may occur in the soldering portion. There is no.

However, in the latter case, the heat sink 70
Since the switching element 62 is laid on the fixed seat portion 71 so as to be overlaid, the fixed seat portion 71 requires a large area, and the width of the fixed seat portion 71 is formed to be substantially the same as the overall lateral width of the heat dissipation plate 70. The fixed seat portion 71 having such a large area is used for the PC.
If it is fixed in close contact with the board 61, the area of the fixed seat portion 71 occupying the surface of the PC board 61 becomes large, and this may interfere with other parts, or the space for mounting other parts may become smaller. is there. And the metal heat sink 7
0 and the leads 63 must be separated from each other to some extent in order to avoid discharge or the like between them, which also causes a large mounting area of the switching element 62 and the heat sink 70. .

[0008]

That is, in the case of the conventional structure, stress acts on the soldering portion of the lead of an electric heat-generating component such as a switching element to cause a solder crack in the soldering portion, or a PC There is a problem that the installation space on the surface of the board 61 becomes large and the effective use of the surface of the PC board 61 is impaired.

Therefore, according to the present invention, stress does not act on the soldering portion of the lead of the electric heating component such as the switching element, so that the generation of solder cracks in the soldering portion is prevented and the surface of the PC board is prevented. It is an object of the present invention to provide a heat dissipation structure for a board-mounted electric heating component that requires a smaller installation space for effective use of the PC board surface.

[0010]

In order to achieve the above-mentioned object, the invention of claim 1 is a printed wiring board; and an electric heat-generating component which is vertically attached to the printed wiring board via leads and generates heat with use; A main heat radiating portion to which the electric heat generating component is closely attached and fixed and is perpendicular to the printed wiring board, and a fixing portion which extends from the main heat radiating portion and is narrower than the main heat radiating portion and fixed to the printed wiring board. A heat dissipation plate having legs; and a heat dissipation structure for a board-mounted electric heating component.

According to the first aspect of the invention, the electric heat-generating component such as the switching element is attached to the heat radiating plate, and the heat radiating plate is fixed to the PC board through the fixing leg portions. The load of the heat sink can be supported by the fixed legs. Therefore, it is possible to reduce the occurrence of stress in the leads of the electric heat-generating component, and it is possible to prevent the occurrence of solder cracks in the soldered portion. Also, the fixed leg extends from the main heat radiating portion and is formed narrower than the main heat radiating portion, so that the fixed leg portion becomes smaller, so that the installation space occupying the PC board surface can be reduced and the PC board surface can be effectively used. become.

According to the second aspect of the present invention, the heat dissipation plate is formed by punching, and a notch is formed at a position opposite to the direction in which the fixed leg extends, and the heat dissipation plate allows another heat dissipation plate to be formed. 2. The fixed leg portion of claim 1 is formed.
2 is a heat dissipation structure of the board-mounted electric heating component described in [3].

According to the second aspect of the present invention, since the notch is formed on the side opposite to the direction in which the fixed leg extends, the other heat radiating plate is fixed to the notch in the remaining plate material punched out of the heat radiating plate. The legs can be formed, so that the other heat dissipation plate can be easily formed by the remaining plates, the waste of material removal does not occur, the material cost can be reduced, and the cost is reduced.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on the first embodiment shown in FIGS. FIG.
2 and 2 show a structure in which a switching element and a heat sink used in an inverter lighting device are attached to a printed wiring board. In the drawing, 1 is a printed wiring board (P
C board), and an electric heating component that generates heat with use, for example, a switching element 2 used in an inverter lighting device is attached to the PC board 1. The switching element 2 has a plurality of leads 3 ... Which are inserted into the PC board 1 and fixed by solder. In this case, the leads 3 ... Stand up substantially vertically from the PC board 1, and therefore the switching element 2 also stands up substantially vertically from the PC board 1.

The switching element 2 is attached to the heat dissipation plate 4. The heat radiating plate 4 is formed by punching a metal plate with a press or the like and partially bending it. The heat radiating plate 4 is formed integrally with the main heat radiating portion 4a to which the switching element 2 is attached and the end portion of the main heat radiating portion 4a. It has a fixed leg portion 4b. The switching element 2 is in close contact with the main heat dissipation portion 4a so that the main heat dissipation portion 4a has a larger area than the contact surface of the switching element 2. The switching element 2 is fixed to the main heat radiation portion 4a by a mounting screw 5. The width x of the fixed leg portion 4b is narrower than the width y of the main heat radiating portion 4a, and the fixed leg portion 4b extends downward from the end of the main heat radiating portion 4a, and the extension lower end is formed by bending. The seat portion 4c is formed. This seat 4c has a fixing screw 6
It is fixed to the PC board 1 by. In this case, the main heat radiating portion 4 a and the fixed leg portion 4 b stand up substantially perpendicular to the PC board 1 and are installed in parallel with the switching element 2.

The fixed leg portion 4 is attached to the end of the main heat radiating portion 4a.
A notch 7 is formed on the side opposite to the extending direction of b. The width of the cutout portion 7 is formed to be equal to the width of the fixed leg portion 4b.

In such a heat dissipation structure, when the switching element 2 generates heat, this heat is transmitted to the heat dissipation plate 4, and is radiated to the outside air from the surface of the switching element 2 itself and the surface of the heat dissipation plate 4. Therefore, the temperature rise of the switching element 2 is suppressed, and the thermal deterioration of the switching element 2 can be prevented. Therefore, the life of the switching element 2 is extended.

The switching element 2 is fixed to the main heat radiating portion 4a of the heat radiating plate 4 by a mounting screw 5, and the heat radiating plate 4 has a fixing leg portion 4b at the end thereof which is fixed with a fixing screw 6.
Therefore, the load of the switching element 2 is supported by the PC board 1 via the heat dissipation plate 4 because it is fixed to the PC board 1. Therefore, the load of the switching element 2 and the heat dissipation plate 4 is not applied to the leads 3 ..., It is possible to avoid the stress from being generated in the soldered portions of the leads 3. Therefore, it is possible to prevent problems such as occurrence of solder cracks in the soldering portion.

Further, since the switching element 2 and the heat dissipation plate 4 stand up substantially perpendicular to the PC board 1, the projected area on the PC board 1 is small and the area occupied on the surface of the PC board 1 can be made small. . The heat radiating plate 4 has the seat portion 4c of the fixed leg portion 4b fixed to the PC board 1 with the fixing screw 6, but the fixed leg portion 4b and the seat portion 4c are formed to be narrower than the main heat radiating portion 4a. Since the contact area of the portion 4c is small, the fixing area of the heat dissipation plate 4 on the surface of the PC board 1 can be reduced.

As a result, it is possible to prevent problems such as the heat radiation plate 4 interfering with other parts and reducing the space for mounting the other parts.

Since the fixed leg portion 4b is formed at the end portion of the main heat radiation portion 4a, the lead 3 of the switching element 2 is formed.
It is possible to largely separate from ..., and it is possible to avoid problems such as electric discharge occurring between them.

In the heat dissipation plate 4 of the above embodiment, a cutout portion 7 is formed at the end of the main heat dissipation portion 4a, and the width of the cutout portion 7 is made equal to the width of the fixed leg portion 4b. Therefore, waste of material removal of the heat dissipation plate 4 is reduced. That is, FIG. 3 shows a punching shape in the case of punching the heat dissipation plate 4 from the sheet metal 10 as a material, and the sheet metal 10 is previously cut into a width Z corresponding to the entire width of the heat radiation plate 4. Such a sheet metal 10
Starting from the above, the material of the heat dissipation plate 4 is sequentially punched, a is the first punched product, b is the second punched product, and n is the nth punched product. As can be understood from these punched products a to n, since the heat dissipation plate 4 of this embodiment has the fixed leg portion 4b and the cutout portion 7 formed at the end of the main heat dissipation portion 4a, the cutout portion 7 is adjacent to the cutout portion 7. It becomes the fixed leg portion 4b of the heat dissipation plate 4, which reduces waste of material removal. in this case,
A blank piece 11 is formed at the end of the first punched product a, and another blank piece 12 is formed next to the main heat dissipation portion 4a of the nth punched product. These blank pieces 11 and 12 are The area of the sheet metal 10 as a whole is very small, and even if these blank pieces 11 and 12 are discarded, the waste of material is extremely small. Therefore, the material cost of the heat dissipation plate 4 can be reduced, and the cost can be reduced.

FIGS. 4 and 5 show an example in which the heat dissipation structure of the switching element having the above structure is applied to a lighting fixture. That is, FIG. 4 shows a lighting fixture for a fluorescent lamp, and 20 is a lighting fixture main body. Sockets 21 and 21 are attached to both ends of the luminaire body 20 in the longitudinal direction,
A straight tube fluorescent lamp 22 is attached to these sockets 21 and 21. An inverter lighting device 23 is housed in the lighting fixture body 20. Inverter lighting device 2
3, the printed wiring board 1 is housed in a space surrounded by a sheet metal casing 24 and a cover 25 as shown in FIG.
A switching element 2 such as a T or a thyristor, and other electronic circuit components (not shown) necessary for transmitting a high frequency,
For example, a noise filter, a full-wave rectifier, an electrolytic smoothing capacitor, a choke ballast, a DC cut capacitor, a resonance inductor, a resonance capacitor, etc. are mounted.

The switching element 2 has the heat radiating plate 4 having the structure shown in FIGS.
It is fixed to the PC board 1 together with. In the case of this embodiment, as shown in FIG. 6, the heat dissipation plate 4 is brought into contact with the inner surface of the casing 24 of the inverter lighting device 23, and the heat dissipation plate 4 and the side wall of the casing 24 are fixed by connecting screws 26. is there.

With such a structure of the lighting equipment, the load of the switching element 2 and the heat radiating plate 4 is applied to the casing 24.
Is also supported by these switching elements 2
And the mechanical support strength of the heat sink 4 is further improved. In addition, the heat of the heat dissipation plate 4 is also transmitted to the casing 24 and released from the casing 24 having a large surface area, so that the heat dissipation efficiency is further improved.

In the case of the first embodiment described above, the example in which the fixed leg portion 4b is formed at one end of the main heat radiating portion 4a has been described, but the present invention is not limited to this, and the first embodiment shown in FIG. 7 and FIG. You may comprise like 2nd Embodiment. In the second embodiment, the main heat dissipation portion 41 is formed at the center of the heat dissipation plate 40, and the fixed leg portions 4 are provided at both ends of the main heat dissipation portion 41.
2, 42, and the seat portions 43, 43 formed at the lower ends of these fixed leg portions 42, 42 are fixed by fixing screws 44, 44.
It is fixed to the C substrate 1. The heat dissipation plate 40 has a fixed leg portion 4
Notches 46, 46 are formed on the opposite sides of the 2, 42. Then, two electric heat-generating components, for example, switching elements 2 and 2 are arranged side by side in the main heat radiation portion 41,
These switching elements 2 and 2 are attached with mounting screws 45 and 45.
Is fixed in close contact with the main heat dissipation portion 41. The leads 3 of the switching elements 2 and 2 are fitted into the PC board 1 and soldered. As a result, the switching elements 2 and 2 are erected substantially vertically to the PC board 1, and the heat dissipation plate 40 is also erected substantially vertically.

Even with such a heat radiation structure, the switching elements 2 and 2 are fixed to the main heat radiation portion 41 of the heat radiation plate 40 by the mounting screws 45, and the heat radiation plate 40 is fixed to the fixed leg portions 42 at both ends. 42 are fixing screws 44 and 4 respectively
Since it is fixed to the PC board 1 by 4, the load of the switching elements 2 and 2 is supported by the PC board 1 via the heat dissipation plate 40, so that the leads 3 ... Lead 3 without load of 40
It is possible to avoid the occurrence of stress in the soldered portion of.

Further, since the switching elements 2 and 2 and the heat dissipation plate 40 stand up substantially perpendicular to the PC board 1, the projected area on the PC board 1 is small and the area occupied on the surface of the PC board 1 can be made small. it can. Therefore, it is possible to prevent problems such as the radiation plate 40 interfering with other components and reducing the space for mounting the other components.

The heat radiating plate 40 has a fixed leg portion 4
Since the notches 46 and 46 are formed on the opposite sides of the Nos. 2 and 42, as shown in FIG. 8, when the material of the sheet metal 10 is punched out, the notches 46 and 46 are adjacent to the heat dissipation plate 40. Of the fixed legs 42, 42, and waste of material removal is reduced.

Furthermore, the present invention is based on FIG. 9 and FIG.
It may be configured as in the third embodiment shown in FIG. Third
The embodiment is an example in which the fixed leg portion 52 is formed at the center of the heat dissipation plate 50, and the main heat radiation portions 51, 51 are formed at both ends of the fixed leg portion 52. In this case as well, the fixed leg portion 52 is located at the end of the main heat radiation portion 51 when viewed from the main heat radiation portion 51. In this heat dissipation plate 50, a seat portion 53 formed at the lower end of the fixed leg portion 52 is fixed by a fixing screw 54.
It is fixed to the C substrate 1. In addition, a cutout portion 56 is formed on the heat dissipation plate 50 on the opposite side of the fixed leg portion 52. Electric heating parts, such as switching elements 2 and 2, are attached to the main heat radiation parts 51 and 51, respectively.
It is tightly fixed by 55. The leads 3 of the switching elements 2 and 2 are fitted into the PC board 1 and soldered. As a result, the switching elements 2 and 2 are connected to the PC.
The heat radiating plate 50 is erected substantially vertically with respect to the substrate 1.

Even with such a heat dissipation structure, the switching elements 2 and 2 are fixed to the main heat dissipation parts 51 and 51 of the heat dissipation plate 50 by the mounting screws 55, and the heat dissipation plate 5 is also provided.
In the case of 0, the central fixed leg portion 52 is fixed to the PC board 1 by the fixing screw 54, so that the loads of the switching elements 2 and 2 are supported by the PC board 1 via the heat dissipation plate 50. It is possible to prevent stress from being generated in the soldered portion of the leads 3 ... Without applying the load of the switching elements 2, 2 or the heat sink 50 to the leads 3.

Further, since the switching elements 2 and 2 and the heat dissipation plate 50 stand up substantially perpendicular to the PC board 1, the projected area on the PC board 1 is small and the area occupied on the surface of the PC board 1 can be made small. it can. Therefore, it is possible to prevent problems such as the radiation plate 50 interfering with other components and reducing the space for mounting the other components.

Further, the heat radiating plate 50 has a fixed leg portion 52.
Since the notch 56 is formed on the opposite side of the sheet metal 10, as shown in FIG. 10, when the material of the sheet metal 10 is punched out, the notch 56 becomes the fixed leg portion 52 of the adjacent heat dissipation plate 50. Less wasted material is taken.

In each of the above-mentioned embodiments, the example in which the switching element is used as the electric heating component has been described. However, the electric heating component is an electric component such as a transistor, a diode, a FET, a thyristor, etc. It can be anything.

[0035]

As described above, according to the invention of claim 1, since the load of the electric heat-generating component and the heat radiating plate can be supported by the fixed leg portion extending from the heat radiating plate, stress is not applied to the lead of the electric heat-generating component. It is possible to prevent the occurrence of solder cracks and prevent the occurrence of solder cracks in the soldering portion. Also, the fixed leg extends from the main heat dissipation part and is formed narrower than the main heat dissipation part, so that it can be made small, and the installation space occupying the PC board surface can be reduced, and the PC board surface can be effectively used. become.

Further, according to the second aspect of the present invention, since the notch is formed on the side opposite to the direction in which the fixed leg extends, the other heat radiating plate is provided in the notch in the remaining plate material punched out of the heat radiating plate. It is possible to form the fixed leg portion of, and thus it is possible to easily form the other heat dissipation plate with the remaining plate, waste of material removal does not occur, the material cost can be reduced, and the cost can be reduced. Become.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention, showing a structure in which a switching element and a heat sink are attached to a printed wiring board.

2A and 2B show a mounting structure of a switching element and a heat radiating plate of the same embodiment, wherein FIG. 2A is a front view and FIG. 2B is a side view.

FIG. 3 is a plan view of the sheet metal showing material removal of the heat dissipation plate of the embodiment.

FIG. 4 is a front view of a fluorescent lamp lighting fixture adopting the mounting structure of the embodiment.

5A and 5B are external views of an inverter lighting device attached to the lighting fixture, FIG. 5A being a plan view and FIG. 5B being a side view.

6 is a sectional view taken along line VI-VI in FIG.

FIG. 7 is a front view showing a second embodiment of the present invention and showing a structure in which a switching element and a heat sink are attached to a printed wiring board.

FIG. 8 is a plan view of the sheet metal showing material removal of the heat dissipation plate of the embodiment.

FIG. 9 is a front view showing a third embodiment of the present invention, showing a structure in which a switching element and a heat sink are attached to a printed wiring board.

FIG. 10 is a plan view of the sheet metal showing material removal of the heat dissipation plate of the embodiment.

11A and 11B show a conventional mounting structure of a switching element and a heat sink, wherein FIG. 11A is a front view and FIG. 11B is a side view.

12A and 12B show another conventional mounting structure for a switching element and a radiator plate, in which FIG. 12A is a front view and FIG. 12B is a side view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... PC board 2 ... Switching element 3 ... Lead 4,40,50 ... Heat dissipation plate 4a, 41,51 ... Main heat dissipation part 4b, 42,52 ... Fixed leg part 4c, 43,53 ... Seat part 5,45,55 … Mounting screws 6,44,54… Fixing screws 7,46,56… Notches

Claims (2)

[Claims] 1. A printed wiring board; an electric heating component which is vertically attached to the printed wiring substrate via a lead and generates heat with use; and the electric heating component is closely attached and fixed to the printed wiring board. A main heat radiating portion that is vertical, and a heat radiating plate that is provided with a fixing leg portion that extends from the main heat radiating portion and is narrower than the main heat radiating portion and that is fixed to the printed wiring board. A heat dissipation structure for board mounted electric heating components. 2. The heat dissipation plate is formed by punching, and a notch is formed at a position opposite to a direction in which the fixed leg extends, and the notch forms a fixed leg of another heat dissipation plate. The heat dissipation structure for a board-mounted electric heating component according to claim 1, wherein a portion is formed.