JP4255340B2 - Power supply heat dissipation structure - Google Patents

Description

  The present invention relates to a heat dissipation structure for a power supply device, and more particularly to a heat dissipation structure provided with a heat dissipation base standing on a substrate.

  Since many power supply devices are provided with a circuit corresponding to a large current or a high voltage, a countermeasure for heat radiation becomes a major issue. For example, the invention described in Patent Document 1 relates to a heat dissipation structure for an inverter power source of a high-frequency heating device. In the present invention, a primary winding of a high-voltage transformer on a substrate is wound around a ferrite core in a cylindrical shape, and the circumferential surface of the cylindrical primary winding is perpendicular to a printed circuit board. The heat dissipating fin with the semiconductor element attached is disposed at a position facing the cylindrical circumferential surface formed by the primary winding. By arranging in this way, a gap is formed between the radiation fin and the high-voltage transformer, so that the flow of the cooling air from the cooling fan becomes smooth, and the cooling effect of the winding and the semiconductor element is improved.

However, since the demand for miniaturization of the power supply device is increasing, the room for changing the arrangement of components on the board is becoming smaller, and it is becoming increasingly difficult to solve this problem. Of course, it is very easy to increase the heat dissipation effect by increasing the size of the heat dissipating fins, but it is extremely difficult to increase the size of the heat dissipating fins under the circumstances where miniaturization of the power supply device is required.
JP 2001-185339 A (page 2-4, FIG. 1)

  The present invention has been made in view of the above-described circumstances. In the heat dissipation structure of the power supply device, it is not necessary to change the arrangement of components on the substrate and to increase the size of the heat dissipation structure, and to prevent the power supply device from being downsized. The purpose is to provide something that does not.

  In order to solve the above problems, the present invention provides a heat dissipation structure for a power supply device including a heat dissipation base provided so as to stand up from a substrate, and the heat dissipation base is attached with an electronic component near the base end of the side surface. The mounting flat surface is formed, and the upper surface of the mounting flat surface is formed to have a divergent shape in a cross section perpendicular to the longitudinal direction. In addition, the shape which spreads at the end means the shape which spreads toward the front-end | tip of a thermal radiation base | substrate.

  Therefore, the heat transferred from the electronic component through the mounting flat surface to the inside of the heat radiating base is conducted while spreading through the widened portion, so that the heat conductivity toward the tip of the heat radiating base is improved, and the heat dissipation Increases effectiveness.

  In the above invention, the heat dissipating base may be one in which a heat dissipating fin is formed on the side surface above the mounting flat surface.

  In the above invention, the heat dissipating base may further include another heat dissipating base having a heat dissipating flat surface formed on an upper end portion thereof and attached to the heat dissipating flat surface. In addition, in the present invention, the heat dissipating base body may further include a heat pipe provided with a groove formed in the flat surface for heat dissipating and disposed inside the groove.

  In the above invention, the heat dissipation base may further include a heat pipe provided with a through hole or a bottomed hole along a longitudinal direction thereof and disposed in the through hole or the bottomed hole. .

  Further, in the above invention, the heat dissipation base may further include a heat pipe provided with a through hole or a bottomed hole along the vertical direction thereof and disposed in the through hole or the bottomed hole. .

  In addition, the heat dissipating base body may be provided with a heat pipe provided with a hollow portion and disposed inside the hollow portion.

  Since the present invention has good thermal conductivity in the tip direction of the heat dissipation base and high heat dissipation effect, it is possible to improve the heat dissipation of the power supply device without changing the arrangement of components on the board and increasing the size of the heat dissipation structure. Can do. In addition, the shape of the divergent shape or the formation of the radiating fin is above the flat surface for mounting, and such deformation is not applied to the portion close to the substrate surface. Don't give. Therefore, it does not hinder downsizing of the power supply device. Further, if another heat dissipation base or a heat pipe is provided, the heat dissipation performance of the heat dissipation structure can be significantly improved without changing the volume of the heat dissipation base itself.

  In the embodiment of the present invention, the greatest feature is that it has a divergent shape in a cross section perpendicular to the longitudinal direction above the mounting flat surfaces formed on both the left and right sides of the heat dissipation base. Therefore, this characteristic point of the present invention will be described prior to the description of each embodiment. FIG. 8 is an explanatory diagram of a heat dissipation structure having a divergent shape. In FIG. 8, 10 is a heat dissipation base, 14 is a heat dissipation fin, 20 is a substrate, 25a, 25b and 51 are semiconductor elements, 30 is a virtual semiconductor element, and 50 is a heat sink. 8B and 8C show a state in which the heat dissipation base 10 is viewed from the end face direction.

  FIG. 8 (b) is an explanatory diagram of the structure that is the basis for the idea of the present invention. The heat dissipation base 10 formed in a plate shape is provided so as to rise from the substrate 20. Further, semiconductor elements 25 a and 25 b are attached to the surface of the heat dissipation base 10 near the substrate 20. As a result of the research, the inventor of the present invention only has a means of providing the heat radiation fins 14 near the upper end of the heat radiating base 10 in order to avoid an increase in the size of the heat radiating structure without changing the arrangement of the components on the substrate. Then, it came to recognition that the heat dissipation efficiency could not be improved sufficiently. That is, if the heat radiation fins 14 are simply formed on the heat radiation base 10, the heat transferred from the semiconductor elements 25a and 25b to the heat radiation base 10 is not sufficiently transmitted to the heat radiation fins 14, and the heat radiation capability of the heat radiation fins 14 cannot be fully utilized. I noticed. If the radiating fins 14 are formed near the semiconductor elements 25a and 25b, a certain degree of improvement is possible. However, if the radiating fins 14 are formed near the surface of the substrate 20, the arrangement of peripheral components must be changed. Therefore, it is not a preferable solution.

  FIG. 8A is an explanatory diagram of matters that are the premise of the present invention. On October 20, 1992, “Thermal Design of Electronic Equipment to Avoid Problems”, pages 26 to 27, published by Nikkan Kogyo Shimbun, Ltd., as shown in FIG. It is described that the heat transferred to the surface of the semiconductor element is transmitted with a 45 ° spread on the left and right with respect to the bonding surface of the semiconductor element.

  FIG. 8C is an explanatory diagram of the basic structure of the present invention. As shown in FIG. 8C, the inventor, in the structure in which the semiconductor elements 25a and 25b are attached to the front and back of the heat dissipation base 10, the heat transferred from these semiconductor elements toward the upper end of the heat dissipation base 10 is In the heat radiating base 10, there is a virtual semiconductor element 30 slightly above the part where the two semiconductor elements 25 a and 25 b are attached, and it is possible to compare the heat transmitted from the virtual semiconductor element 30 toward the upper end of the heat radiating base 10. Noticed. Therefore, assuming that the virtual semiconductor element 30 is provided on the heat radiating base 10, the cross section in the direction orthogonal to the longitudinal direction of the heat radiating base 10 in a portion above the virtual semiconductor element 30 is divergent. It is hypothesized that the thermal conductivity toward the upper end of the heat dissipation base 10 can be increased.

  Therefore, the inventors have studied a heat radiating base having a divergent shape, and have found that the thermal conductivity can be actually increased. Furthermore, it has been found that if the part is inclined so as to spread at least at the end, it can be improved as compared with the case where the part is vertical as shown in FIG. In addition, from the description of the above-mentioned document, the research was conducted assuming that the ability for heat conduction could be further enhanced if the divergent spread angle was 90 ° or more. As a result, it was found that even if this angle is 90 ° or more, the ability to conduct heat is almost the same as that of 90 °. On the other hand, when the angle was 90 ° or less, it was confirmed that the heat conduction ability was inferior. In addition, as will be described later, it may be necessary to mount components provided around the heat radiating base 10. For example, if the portion having a divergent shape expands at an angle of about 180 °, the divergent portion obstructs the work. Therefore, further summing up the above, it can be said that the angle of spreading toward the end is preferably 120 ° or less, preferably close to 90 °, and most preferably 90 °.

  In the present invention, in addition to the above feature points, a heat radiating fin is formed on the end portion of the heat radiating base, and a heat radiating flat surface is formed on the upper end of the heat radiating base. Another feature is that another heat dissipating substrate is attached to the heat dissipating substrate and a heat pipe is provided on the heat dissipating substrate. Hereinafter, examples having these characteristics will be described.

  FIG. 1 is an explanatory diagram of a heat dissipation structure for a power supply device according to a first embodiment of the present invention. In FIG. 1, 10 is a heat dissipation base, 11 is a lower part, 12 is an upper part, 13a and 13b are flat surfaces for mounting, 14 is a heat dissipation fin, 15 is a heat pipe housing recess, 16 is a heat pipe, 18 is a flat surface for heat dissipation, Reference numeral 19 denotes heat conduction, 20 denotes a substrate, 21 denotes a heat sink, 25a and 25b denote semiconductor elements, 26 denotes a lead portion, and 27 denotes a bead core. The heat dissipation structure shown in FIG. 1 is housed in the casing of the power supply apparatus, and a wiring pattern is formed on the substrate 20 and a large number of electronic components are mounted. Description of the casing, the wiring pattern, and the electronic parts not related to the present invention is omitted.

  FIG. 1A is a perspective view of the heat dissipation structure of the power supply device according to the first embodiment. As shown in FIG. 1A, the heat radiating base 10 is provided in a state of rising on the substrate 20, and mounting flat surfaces 13a and 13b are formed on both the front and back surfaces. FIG. 1B is a side view of the heat dissipation base. As shown in FIG. 1B, the mounting flat surfaces 13 and 13b are formed in the lower portion 11 of the heat radiating base 10, and absorb heat from the semiconductor elements 25a and 25b. Moreover, the upper part 12 of the heat radiating substrate 10 is formed in the shape of the above-mentioned divergent shape, and the heat radiating fins 14 are formed on the surface thereof. Further, a heat radiating flat surface 18 is formed at the upper end of the heat radiating base 10, and a heat radiating plate 21 is attached to this surface. The heat radiating fins 14 and the heat radiating plate 21 serve to dissipate heat transmitted to the upper portion 12 of the heat radiating base 10. If the casing of the power supply device is brought into contact with the heat radiating plate 21, the casing also becomes a part of the heat dissipation structure, so that the heat dissipation efficiency can be further improved. In general, a bead core 27 is provided in the lead portion 26 of the semiconductor elements 25a and 25b as a noise countermeasure. The bead core 27 is formed in a cylindrical shape, and is provided by passing the lead part 26 through the inside.

  By the way, in order to increase the mounting density of the electronic components provided on the substrate 20, it is necessary to provide a large number of components in a state of being quite close to the semiconductor elements 25a and 25b. Some of these components perform operations such as adhesive bonding after being mounted on the substrate 20. Since this operation is performed while visually observing the parts, if the upper portion 12 of the heat dissipating base 10 is spread so as to cover the parts to be operated, the work is hindered. Further, when the spread angle is large, the upper part 1 and the peripheral parts 2 approach each other beyond an allowable range. Therefore, the expansion of the upper portion 12 of the heat radiating base body 10 is desirably 120 ° or less even when the heat radiating fins 14 are not provided or the heat radiating fins 14 are very short. Furthermore, it is preferable to secure a certain distance between the heat radiation fin 14 and the semiconductor elements 25a and 25b from the viewpoint of not hindering the air flow around the heat radiation structure.

  Furthermore, a heat pipe housing recess 15 is formed in the flat surface 18 for heat dissipation. In addition, a heat pipe 16 is disposed in the heat pipe housing recess 15. The heat pipe 16 is in close contact with the heat pipe housing recess 15 via heat dissipation (heat transfer) grease, and has a function of quickly conducting heat applied to any part from the heat dissipation base 10 to another part. Therefore, when there is an imbalance in temperature in the horizontal direction (lateral direction) in the upper portion 12 of the heat dissipation base 10, this imbalance can be eliminated by the heat pipe 16.

  Therefore, the heat absorbed by the heat dissipation base 10 from the semiconductor elements 25 a and 25 b is conducted upward while spreading the upper portion 12, as indicated by heat conduction 19. The heat conducted to the upper portion 12 is dissipated into the surrounding atmosphere by the heat radiating fins 14 and the heat radiating plate 21. In addition, the temperature imbalance in the horizontal direction of the heat dissipation base 10 is eliminated by the heat pipe 16. In addition, when the heat pipe 16 is sufficiently longer than the heat radiating base 10, it is possible to radiate heat at a portion of the heat pipe 16 that protrudes from the heat radiating base 10. Further, the heat pipe 16 can be omitted when there is not much temperature imbalance in the heat dissipation base 10. In addition, if the heat dissipating fins 14 and the heat dissipating plate 21 do not have to have a very high heat dissipating capacity, either one or both can be omitted.

  FIG. 2 is an explanatory diagram of the heat dissipation structure of the power supply device according to the second embodiment of the present invention. In FIG. 2, 22 is an external radiation fin, 23 is a fin front-end | tip part, The other code | symbol shows the same thing as the code | symbol of FIG.

  As shown in FIG. 2, the heat dissipation structure of the power supply device according to the second embodiment of the present invention is provided with external heat dissipation fins 22 in place of the heat dissipation plate 21 shown in FIG. That is, it can be said that it is suitable for a case where heat dissipation capability is required more than that according to the first embodiment of the present invention. In FIG. 2, the external heat radiating fin 22 has its fin tip 23 facing directly upward, but in consideration of the shape of the casing of the power supply device, the direction of air flow, or the arrangement of each component. It may be directed horizontally or obliquely upward. Also in this embodiment, the heat pipe 16 can be omitted.

  FIG. 3 is an explanatory diagram of the heat dissipation structure of the power supply device according to the third embodiment of the present invention. In FIG. 3, 10a and 10b are heat radiating base pieces, 17a and 17b are heat pipe housing recesses, and other reference numerals are the same as those in FIG.

  Fig.3 (a) is a side view which shows the arrangement | positioning position of a heat pipe. As shown in FIG. 3 (a), the heat dissipation structure of the power supply device according to the third embodiment of the present invention is such that the heat pipe is disposed inside the heat dissipation base in order to bring the heat pipe closer to the semiconductor element. It is. That is, the heat dissipation base is divided into two heat dissipation base pieces 10a and 10b. Further, heat pipe housing recesses 17a and 17b are formed at positions corresponding to each other of the heat dissipating base pieces 10a and 10b, respectively. The heat pipe housing recesses 17a and 17b serve as through holes for disposing the heat pipe 16 when the heat dissipating base pieces 10a and 10b are integrated. FIG.3 (b) is sectional drawing which shows the inclination state of a heat pipe. Further, as shown in FIG. 3B, when the heat pipe 16 is disposed, the heat pipe housing recesses 17a and 17b are arranged with respect to the heat radiating base pieces 10a and 10b so that the heat pipe 16 is inclined. Are formed diagonally. Moreover, although not shown in figure, the edge part of the heat pipe 16 has protruded outside from the heat pipe accommodation recessed parts 17a and 17b.

  In addition, since the heat pipe of a type that cannot carry heat unless it is disposed in an inclined state moves toward the end portion at a relatively high position, the heat pipe housing recesses 17a, 17b It is desirable to form the power supply device so that the cooling fan side, that is, the windward side is higher in the state of use. This is because air from the cooling fan is more strongly applied to the windward side, so that a higher cooling effect can be obtained than the case where the air is formed in reverse. Further, when a temperature difference occurs between the heat dissipating base pieces 10a and 10b in a state where the power supply device is used, it is desirable to form a relatively higher temperature for the same reason. It should be noted that forming the higher temperature relatively lower is also effective in the case of natural air cooling without providing a cooling fan in the power supply device.

  FIG. 4 is an explanatory diagram of the heat dissipation structure of the power supply device according to the fourth embodiment of the present invention. The reference numerals used in FIG. 4 are the same as those in FIG.

  As shown in FIG. 4, the heat pipe housing recess 17b is formed so as not to form a through-hole in a state combined with the heat pipe housing recess 17a. Therefore, the heat pipe 16 is in a state of being built in the heat dissipation base when the heat dissipation base pieces 10a and 10b are integrated. Therefore, it can be said that this embodiment is suitable when there is no room for disposing the heat pipe 16 in a state of protruding from the heat dissipation base.

  FIG. 5 is an explanatory diagram of the heat dissipation structure of the power supply device according to the fifth embodiment of the present invention. In FIG. 5, 17b1, 17b2, and 17b3 are heat pipe housing recesses, and other reference numerals are the same as those in FIG.

  Fig.5 (a) is sectional drawing which shows the case where a heat pipe is arrange | positioned perpendicularly. As shown in FIG. 5 (a), for heat pipes that can be arranged vertically, recesses are formed in the vertical direction like the heat pipe storage recesses 17b1, 17b2, and 17b3, and the heat pipes are arranged here. It is also possible to set up. If the heat pipe is arranged vertically, the heat transferred from the semiconductor element to the heat dissipation base can be quickly conducted upward.

  FIG. 5B is a cross-sectional view showing a case where the heat pipe is disposed with a large inclination, and is a modification of the one shown in FIG. As shown in FIG.5 (b), about the heat pipe which cannot be arrange | positioned vertically, if the recessed part which inclined largely like the heat pipe accommodation recessed parts 17b1 and 17b2 is formed, and a heat pipe is arrange | positioned here, good. In this way, heat from the semiconductor element can be conducted upward as in the case of FIG. 5B.

  FIG. 6 is an explanatory diagram of the heat dissipation structure of the power supply device according to the sixth embodiment of the present invention. The reference numerals used in FIG. 6 are the same as those in FIG.

  Fig.6 (a) is sectional drawing which shows the case where a flexible heat pipe is arrange | positioned in S shape. When a flexible heat pipe is used, as shown in FIG. 6A, the heat pipe housing recess 17b is formed in an S-shape, and the upper end of the heat pipe is outside the heat radiating base. It is also possible to do. In this way, the heat of the heat radiating base can be evenly conducted to the heat pipe and dissipated to the outside of the heat radiating base.

  FIG.6 (b) is sectional drawing which shows the case where a flexible heat pipe is arrange | positioned in V shape. When the temperature near the center of the heat dissipating base is relatively high in the state where the power supply device is used, as shown in FIG. 6B, a heat pipe housing recess 17b is formed in a V shape, And it is also possible to make the both ends of a heat pipe have come out of the heat dissipation base. In this way, heat near the center of the heat dissipation base can be conducted to the heat pipe and dissipated outside the heat dissipation base. In FIG. 6B, the heat pipe is bent only at one place, but if it is bent at two places, the heat generated near and between the two bending points can be efficiently externalized. It is also possible to dissipate. That is, it can be said that it is desirable to have a structure in which the heat pipe is bent at a portion where the temperature of the heat dissipation base is relatively high.

  FIG. 7 is an explanatory diagram of the heat dissipation structure of the power supply device according to the seventh embodiment of the present invention. In FIG. 5, 24 is a 2nd thermal radiation base | substrate, and another code | symbol shows the same thing as the code | symbol of FIG.

  In this embodiment, a second heat dissipation base 24 is provided at the tip of the heat pipe 16. The heat transmitted from the semiconductor element to the heat dissipation base is transported to the second heat dissipation base 24 by the heat pipe 16 and is dissipated from the second heat dissipation base 24. Therefore, when there is a room for providing the second heat dissipating base in the power supply device, the heat dissipation efficiency can be enhanced by this structure as compared with the other embodiments.

  As described above, in the first to seventh embodiments, the thermal conductivity is improved by making the upper portion of the heat dissipation base wider. Further, by providing the heat pipe, it is possible to improve the imbalance in the heat distribution of the heat dissipation base when the power supply device is used. In addition, a part of the heat pipe is exposed to the outside of the heat radiating base, and another heat radiating base is attached to the exposed heat pipe, so that the heat from the semiconductor element is dissipated to the surrounding atmosphere.

  In each of the above embodiments, the heat dissipation structure for the semiconductor element such as a rectifying diode or MOSFET has been described. However, the present invention can be applied to the case where the heat dissipation target is another device such as a resistor or a transformer. In addition, the heat radiating substrate has been described as having a plate-like shape at the bottom and a divergent shape at the upper part. Shape is applicable. Needless to say, this structure also has an effect even when the semiconductor element is attached to only one surface.

It is explanatory drawing of the thermal radiation structure of the power supply device which concerns on the 1st Example of this invention. It is explanatory drawing of the thermal radiation structure of the power supply device which concerns on 2nd Example of this invention. It is explanatory drawing of the thermal radiation structure of the power supply device which concerns on the 3rd Example of this invention. It is explanatory drawing of the thermal radiation structure of the power supply device which concerns on the 4th Example of this invention. It is explanatory drawing of the thermal radiation structure of the power supply device which concerns on the 5th Example of this invention. It is explanatory drawing of the thermal radiation structure of the power supply device which concerns on the 6th Example of this invention. It is explanatory drawing of the thermal radiation structure of the power supply device which concerns on the 7th Example of this invention. It is explanatory drawing of the thermal radiation structure made into the shape of the end spread.

Explanation of symbols

10: heat radiating substrate 10a: heat radiating substrate piece 10b: heat radiating substrate piece 11: lower part 12: upper part 13a: mounting flat surface 13b: mounting flat surface 14: heat radiating fin 15: heat pipe housing recess 16: heat pipe 17a: heat pipe Storage recess 17b: Heat pipe storage recess 17b1: Heat pipe storage recess 17b2: Heat pipe storage recess 17b3: Heat pipe storage recess 18: Heat radiation flat surface 19: Heat conduction 20: Substrate 21: Heat radiation plate 22: External radiation fin 23 : Fin tip 24: second heat dissipation base 25 a: semiconductor element 25 b: semiconductor element 26: lead part 27: bead core 30: virtual semiconductor element 50: heat sink 51: semiconductor element

Claims (3)

In the heat dissipation structure of the power supply device provided with the heat dissipation base provided to stand up from the substrate,
The heat dissipating base is formed with a mounting flat surface on which electronic components are affixed near the base end of the side surface, and the upper part of the mounting flat surface has a divergent shape in a cross section perpendicular to the longitudinal direction. A heat dissipating plate is provided on the upper surface of the heat dissipating base, a plurality of heat dissipating fins are formed in a horizontal direction from the flat surface for mounting, and the length of the heat dissipating fins decreases in the longitudinal direction. radiation structure of the power supply apparatus characterized by and are. 2. The heat dissipation structure for a power supply device according to claim 1, wherein the heat dissipation base has a heat dissipation fin formed on a side surface above the flat surface for mounting. The heat dissipation base has a groove formed on the flat surface for heat dissipation,
The heat dissipation structure for a power supply device according to claim 2, further comprising a heat pipe disposed inside the groove.

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