JP2013153065A - Heat radiation structure of heater element and air conditioner including the same - Google Patents

Abstract

An object of the present invention is to provide a heat-dissipating structure for a heating element that can improve heat dissipation and productivity, and an outdoor unit for an air conditioner including the same.
A substrate 12 on which a switching element 13 (heat generating element) is mounted on a mounting surface 12b, a metal cover 16 covering an opposite surface 12c opposite to the mounting surface 12b of the substrate 12, and one of the switching elements 13 A heat sink 11 in contact with the surface 13 a and a heat transfer section 15 including a heat radiating sheet 15 a in contact with the other surface 13 b of the switching element 13 and the metal cover 16 through the through hole 12 a provided in the substrate 12 were provided.
[Selection] Figure 2

Description

  The present invention relates to a heat dissipation structure for a heating element mounted on a substrate and an air conditioner including the same.

  A heat dissipating structure for a heat generating element mounted on a substrate is disclosed in Patent Document 1. This heat dissipation structure includes a substrate, a heat generating element, and a heat dissipation block. The heating element is mounted on the mounting surface of the substrate. The heat dissipating block is attached to the surface opposite to the mounting surface (opposite surface). The substrate is provided with a through hole penetrating from the mounting surface to the opposite surface. The through hole is filled with solder. The heat generating element and the heat radiating block are provided in contact with the solder in the through hole.

  When the heating element is energized, heat is generated from the heating element. The heat generated in the heating element is conducted to the heat dissipation block via the solder in the through hole. Thereby, the heat of the heating element is radiated from the heat dissipation block.

  Patent Document 2 discloses a heat dissipation structure including a substrate, a heating element, and a metal case. The heating element is mounted on the mounting surface of the substrate, and the metal case covers the mounting surface. The metal case is bonded to the heat generating element with a conductive adhesive having thermal conductivity. Thereby, the heat of the heating element is conducted to the metal case through the conductive adhesive having thermal conductivity. Thereby, the heat of the heating element is radiated from the metal case.

JP 2000-332171 A (page 3, FIG. 1) Japanese Patent Laying-Open No. 2011-9522 (page 4, page 5, FIG. 1)

  However, in the heat dissipation structure for the heat generating element described in Patent Document 1, it is necessary to cure the solder filled in the through hole. For this reason, there existed a problem that a hardening time was required and productivity fell. In addition, the solder may not be sufficiently filled in the through hole, and a void may be formed. For this reason, there existed a problem that heat dissipation fell.

  In particular, for example, when a large switching element (heating element) used in an air conditioner is mounted on a substrate, it is necessary to increase the number of openings or increase the number of through holes. Therefore, the amount of solder that fills the through hole is greatly increased. As a result, the hardening time of the solder becomes longer and the productivity is significantly reduced. In addition, the filling of the solder into the through-hole is likely to be insufficient, and the heat dissipation is significantly reduced.

  Moreover, in the heat dissipation structure of the heat generating element described in Patent Document 2, the curing time of the conductive adhesive that bonds the heat generating element and the metal case is required. Therefore, productivity is reduced.

  An object of this invention is to provide the heat dissipation structure of the heat generating element which can improve heat dissipation and productivity, and an air conditioner provided with the same.

  In order to achieve the above object, a heat dissipation structure for a heating element according to the present invention includes a substrate on which a heating element is mounted on a mounting surface, a metal cover that covers a surface opposite to the mounting surface of the substrate, It is characterized by comprising a heat sink in contact with one surface, and a heat transfer section made of a heat dissipation sheet that is inserted into a through-hole provided in the substrate and contacts the other surface of the heating element and the metal cover.

  According to this configuration, when the heating element is energized, heat is generated from the heating element. The heat of the heat generating element is conducted to the heat sink and is conducted to the metal cover through the heat transfer portion made of the heat radiating sheet. Thereby, the heat of the heating element is radiated from the heat sink and the metal cover.

  In the heat dissipation structure for a heat generating element having the above configuration, it is more preferable that the heat transfer portion is formed by laminating a plurality of the heat dissipation sheets in a direction perpendicular to the substrate.

  In the heat dissipation structure of the heat generating element configured as described above, the cross-sectional area of the heat transfer portion in a direction parallel to the substrate may be increased between the substrate and the metal cover with respect to the through hole. More preferred.

  In the heat dissipation structure for a heat generating element having the above-described configuration, it is more preferable that the mounting surface of the substrate is covered with the metal cover.

  According to the present invention, in the heat dissipation structure for a heat generating element having the above configuration, the heat generating element is preferably a switching element.

  The air conditioner of the present invention is characterized in that the heat dissipation structure for the heat generating element having the above-described configuration and a blower are provided in the housing. According to this configuration, the heat sink and the metal cover are cooled by the airflow sent from the blower.

  According to the present invention, the heat sink is in contact with one surface of the heating element mounted on the substrate, and the heat transfer portion formed by the heat dissipation sheet inserted through the through hole of the substrate is in contact with the other surface of the heating element and the metal cover. Thereby, the heat of the heating element is radiated from the heat sink and the metal cover. Therefore, heat dissipation can be improved. Moreover, since the solder is not filled in the through hole, the time for hardening the solder becomes unnecessary. Therefore, productivity can be improved.

Front sectional drawing which shows the outdoor unit of the air conditioner of 1st Embodiment of this invention. Side surface sectional drawing of the electrical equipment assembly of the air conditioner of 1st Embodiment of this invention The top view of the electrical equipment assembly of the air conditioner of 1st Embodiment of this invention Side surface sectional drawing of the electrical equipment assembly of the air conditioner of 2nd Embodiment of this invention The top view of the electrical equipment assembly of the air conditioner of 2nd Embodiment of this invention

  A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1: has shown front sectional drawing of the outdoor unit of the air conditioner of 1st Embodiment. The outdoor unit 1 is arranged outside and an exterior is formed by the housing 4. The housing 4 is formed by standing side plates 6 a and 6 b, a front plate (not shown) and a back plate 8 on a bottom plate 5 and fitting the top surface with a top plate 7. The bottom plate 5, the side plates 6a and 6b, the front plate, the back plate 8 and the top plate 7 are formed of a metal such as a steel plate.

  A partition wall 9 is erected on the bottom plate 5 of the housing 4. The partition wall 9 partitions the machine room 20 and the blower room 30. Between the upper end of the partition wall 9 and the top plate 7, a space for arranging an electrical component assembly 10 to be described later is provided. In the machine room 20, the compressor 2 that operates the refrigeration cycle is disposed. A blower 3 and a heat exchanger (not shown) are arranged in the blower chamber 30. The heat exchanger constitutes a refrigeration cycle and exchanges heat with the outside air. The blower 3 is disposed on the front side of the heat exchanger and supplies outside air to the heat exchanger.

  An electrical component assembly 10 is provided at the upper end of the partition wall 9. The electrical component assembly 10 is fitted in a recess (not shown) provided at the upper end portion of the partition wall 9 so as to straddle the machine room 20 and the blower room 30.

  2 and 3 show a side sectional view and a plan view of the electrical component assembly 10. 2, illustration of the screw 19 is omitted, and illustration of the metal cover 16 and the box 41 is omitted in FIG. The electrical assembly 10 includes a substrate 12, a switching element 13 (heating element), a heat sink 11, a heat transfer portion 15 including a heat radiating sheet 15a, and a rectangular parallelepiped electrical box 40 that accommodates these. The electrical box 40 includes a box 41 and a metal cover 16. The box 41 is made of metal and has an upper surface opened. The metal cover 16 is in contact with the box body 41 and covers the upper surface of the box body 41. The electrical component assembly 10 constitutes a heat dissipation structure that dissipates heat generated by the switching element 13 by the heat sink 11, the heat transfer unit 15, and the metal cover 16. The box body 41 may be formed of a resin molded product. Moreover, there is no limitation in particular in the shape of the electrical equipment box 40, A cube etc. may be sufficient.

  A capacitor (not shown) and a switching element 13 are mounted on the mounting surface 12 b of the substrate 12. The capacitor is disposed on the machine room 20 (see FIG. 1) side, and the switching element 13 is disposed on the blower room 30 (see FIG. 1) side.

  The switching element 13 is formed by, for example, a power transistor module. A plurality of terminal leads 18 extend from the switching element 13. The terminal lead 18 is pulled out to the opposite surface 12c opposite to the mounting surface 12b through a through hole (not shown) provided in the substrate 12. Then, one end of the terminal lead 18 is fixed to the wiring pattern (not shown) on the opposite surface 12c with the solder 17. The substrate 12 is not particularly limited, and for example, a printed circuit board in which circuit wiring is configured with a conductor such as copper foil on a glass epoxy board can be used.

  Grease 14 having good thermal conductivity is applied to one surface 13a of switching element 13. The grease 14 is uniformly applied with a thickness of 100 μm to 200 μm. The switching element 13 is in contact with the heat sink 11 via the grease 14. The grease 14 can improve the thermal conductivity from the switching element 13 to the heat sink 11. The grease 14 is not particularly limited, and for example, silicon grease can be used.

  The heat sink 11 is fixed to the switching element 13 by two screws 19. The heat sink 11 may be attached to the switching element 13 with a spring or the like. The heat sink 11 has a plurality of fins 11 a that protrude from the main body portion 11 b toward the outside of the box body 41. Thereby, a surface area increases and heat dissipation improves. The heat sink 11 is formed of a metal having high thermal conductivity, and is formed of, for example, aluminum or an aluminum alloy.

  The main body 11b of the heat sink 11 is formed in a plate shape having a rectangular shape in plan view. Further, the cross-sectional area of the main body portion 11 b in the direction parallel to the substrate 12 is larger than the cross-sectional area of the switching element 13 in the direction parallel to the substrate 12. Thereby, heat dissipation can be improved. The shape of the main body 11b is not particularly limited, and may be, for example, a circular shape or a square shape.

  The metal cover 16 covers the opposite surface 12 c opposite to the mounting surface 12 b of the substrate 12. Thereby, the solder 17 is protected and a short circuit can be prevented. The metal cover 16 is made of a metal having high thermal conductivity, and is made of, for example, aluminum or an aluminum alloy.

  Further, the mounting surface 12 b of the substrate 12 is covered by the box 41. An opening 16 a is provided on the bottom surface of the box body 41. The heat sink 11 is attached to the switching element 13 through the opening 16a. At this time, the heat sink 11 is disposed outside the box 41.

  The substrate 12 is provided with a through hole 12 a facing the switching element 13. The through hole 12a penetrates from the mounting surface 12b to the opposite surface 12c. A plurality of heat dissipation sheets 15a are inserted through the through holes 12a. The plurality of heat dissipation sheets 15 a are stacked in a direction perpendicular to the substrate 12 from the other surface 13 b of the switching element 13 to the metal cover 16.

  The heat transfer unit 15 is configured by stacking a plurality of heat dissipation sheets 15a. Thereby, the heat transfer part 15 contacts the other surface 13 b of the switching element 13 and the metal cover 16. In addition, you may comprise the heat-transfer part 15 with the one heat dissipation sheet 15a which contact | connects the other surface 13b of the switching element 13, and the metal cover 16. FIG. In this case, the thickness of one heat radiating sheet 15 a may be the same as the distance between the other surface 13 b of the switching element 13 and the metal cover 16.

  An adhesive (not shown) is disposed on one surface of the heat dissipation sheet 15a and is covered with a film material (not shown). The film material is peeled off, and the heat dissipation sheet 15a is attached to the other surface 13b of the switching element 13. Sequentially, the heat-dissipating sheets 15a are laminated to be stacked. In addition, you may arrange | position an adhesive on both surfaces of the thermal radiation sheet 15a.

  The heat dissipation sheet 15a has insulation and thermal conductivity. Thereby, the heat generated in the switching element 13 can be easily conducted to the metal cover 16 through the conductive portion 15. Further, the heat dissipation sheet 15a is formed of, for example, silicon resin. In addition, you may form the thermal radiation sheet 15a with an acrylic resin.

  In the outdoor unit 1 of the air conditioner configured as described above, when the refrigeration cycle is operated by the compressor 2, the heat exchanger becomes the low temperature side or the high temperature side of the refrigeration cycle. External air is taken in through the opening (not shown) provided in the back plate 8 and the side plate 6a of the outdoor unit 1 by driving the blower 3, and the external air is supplied toward the heat exchanger. As a result, the heat exchanger exchanges heat with the outside air. The outside air that has passed through the heat exchanger is exhausted from an opening (not shown) provided in the front plate of the outdoor unit 1.

  At this time, heat is generated from the switching element 13. The heat generated in the switching element 13 is conducted to the heat sink 11 and is conducted to the metal cover 16 through the heat transfer unit 15. Thereby, the heat of the switching element 13 is radiated from the heat sink 11 and the metal cover 16. Further, the heat sink 11 and the metal cover 16 are cooled by the airflow sent from the blower 3. Thereby, the temperature of the switching element 13 can be reduced reliably.

  According to the present embodiment, the substrate 12 on which the switching element 13 (heat generating element) is mounted on the mounting surface 12b, the metal cover 16 that covers the opposite surface 12c on the opposite side of the mounting surface 12b of the substrate 12, and the switching element 13 The heat sink 11 is in contact with one surface 13a, and the heat transfer section 15 is formed of a heat radiation sheet 15a that is inserted into a through hole 12a provided in the substrate 12 and is in contact with the other surface 13b of the switching element 13 and the metal cover 16. . Thereby, the heat of the switching element 13 is conducted to the heat sink 11 and is also conducted to the metal cover 16 through the heat transfer portion 15 including the heat radiating sheet 15 a and is radiated from the heat sink 11 and the metal cover 16. Therefore, heat dissipation can be improved.

  Further, it is not necessary to fill the through hole 12a with a metal material such as solder and cure it. Therefore, the curing time becomes unnecessary, and the productivity of the electrical component assembly 10 can be improved. In addition, since the voids that are likely to occur when the solder is filled in the through holes are not formed, the heat dissipation can be improved.

  Further, since the heat transfer section 15 is formed by laminating a plurality of heat radiation sheets 15a in the direction perpendicular to the substrate 12, the thickness of the heat transfer section 15 (thickness in the direction perpendicular to the substrate 12) can be easily set. Can be adjusted.

  Further, since the metal cover 16 is in contact with the metal box 41, the heat generated by the switching element 13 can be conducted to the box 41 via the metal cover 16. Therefore, by covering the mounting surface 12b of the substrate 12 with the box 41, the heat radiation area can be increased as compared with the case where only the opposite surface 12c is covered, and the heat dissipation can be further improved.

  Moreover, since the outdoor unit 1 of the air conditioner includes the above-described heat dissipation structure of the switching element 13 and the blower 3 in the housing 4, the temperature of the switching element 13 is quickly and easily controlled by the airflow sent from the blower 3. It can be reliably lowered. Therefore, the lifetime of the switching element 13 can be extended and the reliability of the air conditioner can be improved.

  When the current increases with power-up of the air conditioner or when the switching frequency increases during energy saving operation, the switching element 13 generates more heat. Moreover, the size of the heat sink 11 may be limited with the downsizing of the outdoor unit 1. According to the present embodiment, the heat of the switching element 13 can be dissipated not only from the heat sink 11 but also from the metal cover 16, so that the heat dissipation can be reliably improved even in these cases.

  In addition, if the through hole 12a is filled with a metal such as solder, it is not possible to secure a sufficient insulation distance between the different polarities of the substrate pattern and the component lead portion. For this reason, there is a possibility of causing malfunction of the electrical component assembly 10. According to the present embodiment, since the insulating heat radiation sheet 15a is disposed in the through hole 12a, a sufficient insulation distance can be secured between the different polarities of the substrate pattern and the component lead portion. Therefore, the possibility of malfunction of the electrical component assembly 10 due to the short insulation distance can be prevented.

  Next, a second embodiment will be described. 4 and 5 show a side sectional view and a plan view of the heat dissipation structure of the switching element 13 (heat generating element) of this embodiment. For convenience of explanation, the same reference numerals are given to the same parts as those in the first embodiment shown in FIGS. In the present embodiment, the configuration of the heat transfer section 15 is different from that of the first embodiment. Other parts are the same as those in the first embodiment.

  The area of the heat dissipation sheet 15a laminated between the opposite surface 12c of the substrate 12 and the metal cover 16 is larger than the area of the heat dissipation sheet 15a laminated in the through hole 12a. That is, the cross-sectional area of the heat transfer portion 15 in the direction parallel to the substrate 12 is larger between the substrate 12 and the metal cover 16 than in the through hole 12a.

  Thereby, the heat dissipation rate of the switching element 13 can be increased without greatly opening the through hole 12. Therefore, heat dissipation can be improved while maintaining the strength of the substrate 12.

  The heat transfer section 15 may be configured by providing one heat radiating sheet in contact with the opposite surface 12 c and the metal cover 16 and providing one heat radiating sheet in contact with the heat radiating sheet and the switching element 13.

  According to this embodiment, the same effect as that of the first embodiment can be obtained. Further, the cross-sectional area of the heat transfer portion 15 in the direction parallel to the substrate 12 is increased between the substrate 12 and the metal cover 16 with respect to the inside of the through hole 12a. Thereby, the heat dissipation rate of the switching element 13 can be increased without greatly opening the through hole 12. Therefore, heat dissipation can be further improved while maintaining the strength of the substrate 12.

  The embodiment of the present invention has been described above, but the scope of the present invention is not limited to this, and various modifications can be made without departing from the spirit of the invention.

  For example, in the first and second embodiments, the switching element 13 has been described as an example of a heating element, but the present invention is not limited to this. The heating element may be an electronic component that generates a relatively large amount of heat, and may be, for example, a shunt resistor inserted into a circuit for current measurement.

  Moreover, although the outdoor unit 1 of the air conditioner has been described as an example, the heat dissipation structure of the heat generating element may be provided in an electric device other than the air conditioner.

  Further, if the opposite surface 12 c is covered with the metal cover 16, the heat dissipation can be improved. Therefore, the mounting surface 12 b need not be covered with the box 41. However, since the heat radiation area can be increased and the heat radiation performance can be further improved, it is preferable to cover the mounting surface 12b of the substrate 12 with the box body 41.

  Further, when the box 41 of the electrical box 40 is formed of a resin molded product, the metal cover 16 may cover the four side surfaces of the box 41 in addition to the upper surface of the box 41. Alternatively, the metal cover 16 may cover the bottom surface and the three side surfaces of the box body 41 in addition to the top surface of the box body 41. Thereby, since a heat dissipation area increases, heat dissipation can be improved. In addition, as resin used for the box 41, a polystyrene resin can be used, for example.

  A plurality of through holes 12a may be provided. Thereby, heat dissipation can be improved further. It is desirable that the number of the through holes 12a is one because the strength of the substrate 12 can be maintained and the labor of attaching the heat radiation sheet 15a can be saved.

  INDUSTRIAL APPLICABILITY The present invention can be used for a heat dissipation structure for a heating element mounted on a substrate and an air conditioner including the heat dissipation structure.

DESCRIPTION OF SYMBOLS 1 Outdoor unit 2 Compressor 3 Blower 4 Case 5 Bottom plate 6a, 6b Side plate 7 Top plate 8 Back plate 9 Partition wall 10 Electrical assembly 11 Heat sink 11a Fin 12 Substrate 12a Through hole 12b Mounting surface 12c Opposite surface 13 Switching element element)
13a One side 13b The other side 14 Grease 15 Heat transfer part 15a Heat dissipation sheet 16 Metal cover 17 Solder 18 Terminal lead 19 Screw 20 Machine room 30 Blower room 40 Electrical box 41 Box

Claims (6)

  A substrate that mounts the heating element on the mounting surface, a metal cover that covers a surface opposite to the mounting surface of the substrate, a heat sink that is in contact with one surface of the heating element, and a through hole provided in the substrate A heat dissipation structure for a heat generating element, comprising: a heat transfer portion made of a heat dissipation sheet in contact with the other surface of the heat generating element and the metal cover.   The heat-radiating structure for a heating element according to claim 1, wherein the heat transfer section is formed by laminating a plurality of the heat-dissipating sheets in a direction perpendicular to the substrate.   The cross-sectional area of the heat transfer portion in a direction parallel to the substrate is increased between the substrate and the metal cover with respect to the inside of the through hole. Heat dissipation structure of the heating element.   The heat dissipation structure for a heat generating element according to any one of claims 1 to 3, wherein the mounting surface of the substrate is covered with the metal cover.   5. The heat dissipation structure for a heating element according to claim 1, wherein the heating element is a switching element.   An air conditioner comprising the heat dissipating structure for a heat generating element according to any one of claims 1 to 5 and a blower in a casing.

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