JP2008301592A - Power supply unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve heat dissipation by improving the ventilation of a power supply unit. <P>SOLUTION: The power supply unit 8 is provided with a heat dissipation body 9, a base plate 10 attached on the heat dissipation body 9, first and second heat-generating components 12, 13A, 13B surface-mounted on the base plate 10, and a circuit board 11 electrically connected to the first and second heat-generating components 12, 13A, 13B and disposed on a position facing the base plate 10. The power supply unit 8 is provided with a first ventilation portion 15 for connecting the lower part of the heat dissipation body 9 near the lower part of the first heat-generating component 12 to the component mounting side of the base plate 10, and a second ventilating portion 15 penetrating through the circuit board 11 near the upper part of the first heat-generating component 12. With this configuration, the power supply unit 8 has improved ventilation and heat dissipation. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a power supply unit.

  As shown in FIG. 8, a power supply unit 1 disclosed in the past includes a radiator 2 such as a chassis, a base plate 3 attached to the radiator 2, and a transformer 4 (heat generating component) surface-mounted on the base plate 3. ) And a power semiconductor element 5 (heat-generating component), and a circuit board 6 that is electrically connected to the transformer 4 and the power semiconductor 5 and disposed at a position facing the base plate 3. A plurality of control elements 7 are mounted on the circuit board 6.

  Thus, by integrating a plurality of electronic components as a unit, the wiring distance between the electronic components is shortened, and noise can be reduced. In addition, since it is not necessary to mount each individual electronic component or design a circuit arrangement or the like, the design man-hour is reduced, which greatly contributes to improvement in productivity.

As prior art document information relating to the invention of this application, for example, Patent Document 1 is known.
JP 2005-184883 A

  The power supply unit 1 having the above configuration has a problem of low heat dissipation.

  The reason is that heat is trapped between the base plate 3 and the circuit board 6 due to heat from heat-generating components such as the transformer 4 and the power semiconductor element 5. If the heat is accumulated in this way, the transformer 4 and the power semiconductor element 5 may be thermally deteriorated.

  Therefore, an object of the present invention is to improve the air permeability of the power supply unit and to improve the heat dissipation.

  In order to achieve this object, the present invention provides a first ventilation portion that is in the vicinity of the lower portion of the first heat generating component and connects the lower side of the radiator and the component mounting surface side of the base plate, and the upper portion of the first heat generating component. It is assumed that a second ventilation portion that is in the vicinity and penetrates the circuit board is formed.

  Thereby, this invention can improve the air permeability of a power supply unit, and can improve heat dissipation.

  This is because the first and second ventilation parts are provided in the vicinity of the first heat-generating component, so that heat convection occurs, and heated air flows from the inside of the power supply unit to the outside. This is because external cold air flows.

  Thus, this invention can improve the air permeability of a power supply unit, and can improve heat dissipation.

(Embodiment 1)
Hereinafter, the power supply unit in the present embodiment will be described.

  First, the structure of this embodiment will be described.

  As shown in FIG. 1A, the power supply unit 8 of the present embodiment includes a radiator 9, a thermally conductive substrate 10 as a base plate attached to the radiator 9, and the thermally conductive substrate 10. And a circuit board 11 arranged at an opposing position. The thermally conductive substrate 10 includes a transformer 12 (heat generating component), a power semiconductor element 13A (heat generating component) such as an FET disposed on the input circuit side of the transformer 12, and a diode disposed on the output circuit side. The power semiconductor element 13B (heat generating component) is surface-mounted, and the transformer 12, the power semiconductor elements 13A and 13B, and the circuit board 11 are electrically connected. A plurality of control elements 14 are mounted on the circuit board 11. In the present embodiment, power semiconductor elements 13A and 13B are arranged at both ends of the transformer 12, respectively, and these are arranged in a line.

  The power supply unit 8 includes a ventilation portion (15A in FIG. 2) near the lower portion of the transformer 12 and connecting the outer side (lower side) of the radiator 9 and the component mounting surface side of the heat conductive substrate 10, and the transformer 12 And a ventilation portion 15B penetrating the circuit board 11 is formed.

  Further, the heat conductive substrate 10 in the present embodiment includes a heat transfer plate 16 joined to the radiator 9 by screwing or the like, an insulating layer 17 disposed on a part of the heat transfer plate 16, and this insulation. And a conductor pattern 18 disposed on the layer 17. The connection terminal 18A portion at the end of the conductor pattern 18 is bent and connected to the circuit board 11. In the present embodiment, the connection terminal 18A is drawn out from the conductor pattern 18, but the connection terminal may be drawn out from the power semiconductor elements 13A and 13B and connected to the circuit board 11. In that case, if the heat generating component is resin-molded below the heat generating component in the small current region, the insulating layer 17 may not be formed and may be directly bonded to the heat transfer plate 16.

  In this embodiment, the transformer 12 is directly bonded to the heat transfer plate 16 with an adhesive, and the power semiconductor elements 13A and 13B are bonded to the conductor pattern 18 with solder or an adhesive.

  Furthermore, in the present embodiment, the circuit board 11 has a hole 19 that is opened larger than the upper surface of the transformer 12, and the upper portion of the transformer 12 is inserted into the hole 19, and the gap between the transformer 12 and the circuit board 11 in the hole 19. Is the ventilation portion 15B.

  In the present embodiment, the ventilation portion 15A is formed by holes 20A and 20B opened in the heat transfer plate 16 and the heat radiating body 9, respectively, so as to penetrate the heat conductive substrate 10 and the heat radiating body 9. . As shown in FIG. 2, in the present embodiment, the hole 20B (including the hole 20A in FIG. 1A) is not opened between the transformer 12 and the power semiconductor elements 13A and 13B. Near the power semiconductor elements 13A and 13B. That is, in this embodiment, the transformer 12 and the power semiconductor elements 13A and 13B are connected by the heat conductive substrate 10.

  Further, in the present embodiment, as shown in FIG. 1A, the transformer 12 includes a core portion 21 and a coil portion 22, and the core portion 21 is provided at the middle leg 23 and at both upper and lower ends of the middle leg 23, respectively. The back leg 24 is formed. The coil portion 22 is disposed on the outer periphery of the middle leg 23 of the core portion 21 and between the upper and lower back legs 24, and the lower back leg 24 is bonded to the heat transfer plate 16.

  Further, in the present embodiment, as shown in FIG. 1B, the holes 20B formed in the heat transfer plate 16 of the heat conductive substrate (10 in FIG. 1A) are formed in the radiator 9. The opening area is smaller than that of the hole 20A and is located inside the hole 20A.

  The opening on the upper side (transformer 12 mounting side) of the hole 20B formed in the heat transfer plate 16 is formed with a curved surface 25 curved inward from the upper surface of the heat transfer plate 16 toward the inner wall of the hole 20B. The opening on the lower side of the hole 20B has a protrusion 26 protruding downward.

  The members of the present embodiment will be described below.

  In the present embodiment, a winding coil is used as the coil portion 22, and a copper wire coated with the insulating layer 17 is used as the winding. In addition to the winding, the coil portion 22 may be formed of a copper plate or the like. The core portion 21 was made of soft magnetic ferrite obtained by sintering a metal oxide such as iron or manganese. Other than the ferrite, the core portion 21 may be a magnetic material.

  The insulating layer 17 of the thermally conductive substrate 10 used in the present embodiment is a highly thermally conductive composite in which an inorganic filler such as alumina is kneaded with about 70 wt% to 95 wt% in a thermosetting resin such as an epoxy resin. It is formed by thermosetting a resin. Further, the thickness was set to 0.6 mm in order to enhance the withstand voltage. The particle size of the inorganic filler was 0.1 μm to 100 μm, and the thermal conductivity of the insulating layer 17 was 2.0 W / mK to 5.0 W / mK.

  Further, as the heat transfer plate 16 of the heat conductive substrate 10, a metal plate such as an aluminum plate or a copper plate having a thickness of about 0.5 mm to 1.0 mm is used, and the conductor pattern 18 has a thickness of about 0.1 mm to 0.3 mm. A copper plate was used.

  Further, as an adhesive for adhering the transformer 12 to the heat transfer plate 16, a resin having a smaller elastic modulus (softer) than the high thermal conductive composite resin of the insulating layer 17 was used.

  In the present embodiment, a thermosetting resin is used as the insulating layer 17, but a thermoplastic resin such as a photocurable resin, a liquid crystal polymer having high thermal conductivity, or PPS may be used.

  As the radiator 9, an aluminum chassis having a thickness of about 2.0 mm was used. If fins are arranged instead of the chassis, the surface area can be increased and the heat dissipation can be further improved.

  Next, the manufacturing method of the power supply unit 8 in this Embodiment is demonstrated.

  First, the mass of the high thermal conductive composite resin is gathered into a round shape (or a bowl shape, a trapezoidal shape, a cylindrical shape, a spherical shape) so that the center is convex, and placed on the left and right sides of the heat transfer plate 16 shown in FIG. Then, the high thermal conductive composite resin is stretched to form a sheet by a heat press or a vacuum heat press. The heat transfer plate 16 is previously provided with a hole 20B by punching or the like. Here, in the present embodiment, by punching from the mounting surface side of the transformer 12 toward the joint surface side with the radiator 9, as shown in FIG. A curved surface 25 that is curved inward from the heat transfer plate 16 toward the inner wall of the hole 20B is formed, and a lower opening of the hole 20B forms a protruding portion 26 that protrudes downward.

  Next, the heat transfer plate 16 is heated at 100 ° C. for 1 to 2 minutes to solidify the insulating layer 17 and removed from the mold. Then, it is placed in a furnace at 200 ° C. for several hours, and the epoxy resin of the insulating layer 17 is polymerized and finally cured. In the present embodiment, before the insulating layer 17 is cured, the conductor pattern 18 is disposed on the insulating layer 17 in advance and integrated before being cured. Here, in the case where a circuit is formed in the conductor pattern 18, if the conductor pattern 18 is embedded so as to be substantially flush with the insulating layer 17, a high thermal conductive composite resin enters between the patterns to improve electrical insulation. In addition, the electronic component can be easily mounted on the conductor pattern 18. The conductive pattern 18 may be disposed on the insulating layer 17 with a highly heat conductive adhesive after the insulating layer 17 is cured.

  A solder layer or a tin layer (not shown) may be formed on the upper surface of the conductor pattern 18 by electroplating. In this way, the insulating layer 17 is formed except for the central portion of the heat transfer plate 16.

  Thereafter, the coil portion 22 is disposed on the outer periphery of the middle leg 23 of the core portion 21 of the transformer 12.

  Next, the lower core portion 21 is disposed on the heat transfer plate 16 and bonded with an adhesive. And the upper core part 21 is arrange | positioned so that the lower core part 21 may be opposed.

  Thereafter, power semiconductor elements 13A and 13B such as FETs and diodes are mounted on the conductor pattern 18, and the connection terminal 18A portion outside the conductor pattern 18 is bent and raised.

  Next, the heat transfer plate 16 is attached to the radiator 9 having the holes 20A. At this time, the holes 20A of the radiator 9 and the holes 20B of the heat transfer plate 16 were arranged so as to overlap each other. Further, the conductor pattern 18 is inserted into the circuit board 11 on which the control element 14 is mounted. In the present embodiment, the circuit board 11 is provided with a hole 19 in the transformer 12 portion, and the transformer 12 is fitted into the hole 19.

  The effect in this Embodiment is demonstrated below.

  In the present embodiment, the air permeability of the power supply unit 8 can be improved and the heat dissipation can be improved.

  When heat is trapped between the heat conductive substrate 10 and the circuit board 11 due to heat from the transformer 12 and the power semiconductor elements 13A and 13B, heat convection is caused by the ventilation portions 15A and 15B provided in the vicinity of the transformer 12. This is because heated air flows out from the inside of the power supply unit 8 to the outside, and external cold air flows into the power supply unit 8.

  Thereby, this invention can improve the air permeability of the power supply unit 8, and can improve heat dissipation.

  In the present embodiment, since the core portion 21 is insulative, the transformer 12 can be directly bonded to the heat transfer plate 16, and the heat of the transformer 12 is quickly released to the heat transfer plate 16 made of a metal having high thermal conductivity. Can do. Further, since the insulating layer 17 is not formed in the lower portion of the transformer 12 and in the vicinity thereof, the hole 20B may be formed in the portion where the heat transfer plate 16 is exposed, that is, only the metal plate, and the processing is easy. is there.

  Furthermore, in the present embodiment, by inserting the upper portion of the transformer 12 into the hole 19 formed in the circuit board 11, the entire power supply unit 8 can be reduced in height. Here, when the height is reduced in this manner, heat is more likely to be trapped between the circuit board 11 and the heat conductive substrate 10, but heat dissipation can be improved by forming the ventilation portions 15 </ b> A and 15 </ b> B. Moreover, by using a part of this hole 19 as the ventilation part 15B, a manufacturing process can be reduced and production efficiency can be improved.

  Further, in the present embodiment, as shown in FIG. 2, the transformer 12 and the power semiconductor elements 13A and 13B are connected by the heat conductive substrate 10, and the ventilation portion 15A is near the lower portion of the transformer 12. Since the power semiconductor elements 13A and 13B are not opposed to each other, the heat dissipation can be improved while the transformer 12 and the power semiconductor elements 13A and 13B are soaked.

  In the present embodiment, in the vicinity of the lower part of the transformer 12, the holes 20A and 20B serving as the ventilation portions 15A are formed in the heat transfer plate 16 and the heat radiating body 9, so that the vibration of the transformer 12 is buffered and the heat conduction The stress load applied to the entire conductive substrate 10 can be reduced. Further, in the present embodiment, the vibration of the transformer 12 can be absorbed by using a resin having a relatively low elastic modulus (soft) as an adhesive for bonding the transformer 12 to the heat transfer plate 16.

  Further, in the present embodiment, as shown in FIG. 1B, the hole 20B formed in the heat transfer plate 16 of the heat conductive substrate 10 has a smaller opening area than the hole 20A formed in the radiator 9. Therefore, even when the thickness of the heat transfer plate 16 is made thinner than that of the radiator 9 as in the present embodiment, the mechanical strength of the heat transfer plate 16 can be prevented from being weakened by the holes 20B.

  The opening on the upper side of the hole 20B (the transformer 12 mounting side) formed in the heat transfer plate 16 is a curved surface curved inward from the upper surface of the heat transfer plate 16 toward the inner wall of the hole 20B by punching the hole 20B. 25 is formed. The opening on the lower side of the hole 20B has a protrusion 26 protruding downward. Thereby, in this embodiment, the curved surface 25 formed by punching is disposed on the mounting surface of the transformer 12, the unevenness of the mounting surface of the transformer 12 is suppressed, the adhesion between the transformer 12 and the heat transfer plate is improved, and heat dissipation Can be improved. Further, the protrusion 26 formed by punching is located inside the hole 20A because the hole 20B is smaller than the hole 20A and formed inside. Therefore, also when the projection part 26 is formed, the unevenness | corrugation between the heat radiator 12 and the heat exchanger plate 16 can be reduced, and it contributes to heat dissipation improvement by adhesiveness improving.

  In this embodiment, a heat transfer plate 16 made of metal, an insulating layer 17 made of filler-containing resin, and a conductor pattern 18 made of metal are provided as a base plate for mounting the transformer 12 and the power semiconductor elements 13A and 13B. Although the heat conductive substrate 10 is used, a resin plate may be used, or an aluminum plate, a copper plate, or the like may be used when an electronic component that does not require insulation is mounted.

(Embodiment 2)
The difference between the present embodiment and the first embodiment is that a ventilation portion 15A is formed between the transformer 12 and the power semiconductor elements 13A and 13B as shown in FIG. The ventilation portion 15A includes a hole 20B formed in the heat transfer plate 16 and a hole (20A in FIG. 4) formed in the radiator.

  In the present embodiment, as shown in FIG. 4, the conductor pattern 18 is bent upward on the transformer 12 side of the power semiconductor element 13A.

  The effect of this embodiment will be described below.

  In the present embodiment, the air permeability in the entire power supply unit 8 can be improved and the heat dissipation can be improved while the heat insulation between the transformer 12 and the power semiconductor elements 13A and 13B is achieved.

  That is, in this embodiment, as shown in FIG. 3, since the transformer 12 and the power semiconductor elements 13A and 13B are integrated by a single heat conductive substrate 10, the heat transfer plate 16 portion having a large surface area. Can efficiently dissipate heat, contributing to noise reduction and productivity improvement. On the other hand, when either the transformer 12 or the power semiconductor elements 13A and 13B becomes high temperature by sharing the heat transfer plate 16 having high thermal conductivity, heat from one of them is transferred to the other, and any components are It may become hot.

  On the other hand, in the present embodiment, as shown in FIG. 4, holes 20A and 20B are formed in the heat transfer plate 16 and the radiator 9 between the transformer 12 and the power semiconductor elements 13A and 13B. . Therefore, heat transfer between the transformer 12 and the power semiconductor elements 13A and 13B is suppressed, and further, hot air can be released by the ventilation portion 15A constituted by the holes 20A and 20B. As a result, heat dissipation is improved. Can be made.

  Further, in the present embodiment, as shown in FIG. 4, since the ventilation portion 15A is formed between the transformer 12 and the power semiconductor element 13A, the connection terminal 18A of the conductor pattern 18 is bent from the ventilation portion 15A. The angle of the bent connection terminal 18A can be finely adjusted.

  In the present embodiment, since the bent connection terminal 18A is arranged on the transformer 12 side, the cool air outside the power supply unit 8 expels the hot air around the transformer 12 due to the chimney effect of the connection terminal 18A, and heat dissipation. Can be increased.

(Embodiment 3)
The difference between the present embodiment and the first embodiment is that, as shown in FIG. 5, a part of the hole 20B (and the hole 20B in FIG. 6) in which the ventilation portion 15A is formed large in the lower part of the transformer 12 and in the vicinity thereof. It is a point that has been configured.

  That is, in this embodiment, a large hole 20B is formed leaving a space where the transformer 12 can be bonded to the heat transfer plate 16, and the hole 20A is also formed in the radiator 9 so as to face the hole 20B as shown in FIG. Formed.

  As a result, the present invention improves the air permeability of the power supply unit 8 and exposes a part of the core portion 21. By applying cold air to the core portion 21 from the outside of the power supply unit 8, as a result, the power supply unit 8. The heat dissipation can be improved.

  Since other configurations and effects are the same as those of the first embodiment, description thereof is omitted.

(Embodiment 4)
The difference between the present embodiment and the first embodiment is that, as shown in FIG. 7, the ventilation portion 15 </ b> A is configured by a part of a hole 20 </ b> A formed in the heat radiator 9. That is, in the present embodiment, no hole is formed in the heat transfer plate 16, and the ventilation portion 15 </ b> A is configured only by the hole 20 </ b> A formed in the radiator 9 at a portion corresponding to the outside of the heat transfer plate.

  Further, in the present embodiment, the heat transfer plate 16 is narrow at the mounting portion of the transformer 12, and is shaped so that a part of the transformer 12 protrudes.

  If the hole 20A of the radiator 9 is formed so as to correspond to the outer periphery of the portion where the transformer 12 protrudes, the ventilation portion 15A of the present embodiment can be configured.

  As a result, the present invention can reduce the production process because the punching process only requires the radiator 9.

  In the present embodiment, since the width of the heat transfer plate 16 is narrowed at a portion corresponding to the hole 20A, the hole 20A can be formed small. Thereby, it is possible to prevent the heat dissipation area from being excessively reduced by increasing the size of the hole 20A.

  In the present embodiment, a part of the hole 20A is used as the ventilation part 15A, but the hole 20A may be provided only in a part corresponding to the ventilation part 15A.

  When it is desired to omit the process of changing the width of the heat transfer plate 16, the width remains constant and the area of the hole 20A is increased.

  Since other configurations and effects are the same as those of the first embodiment, description thereof is omitted.

  In the embodiment described above, a winding coil is used for the coil portion 22, but a flat shape or a shape incorporated in the core portion 21 may be used. The shape of the core portion 21 may be a split type (EE type), an EI type, or a UU type combining a so-called E type and an E type, or a non-split type so-called toroidal core.

  In the above embodiment, the transformer 12 is used as the heat generating component. However, a power inductor component such as a choke coil may be used.

  The present invention is a power supply unit in which a transformer, a power semiconductor element, and a circuit board are integrated. The power supply unit can be improved in air permeability and heat dissipation. Can be used for the power supply unit.

(A) Cross-sectional view of the power supply unit according to Embodiment 1 of the present invention (XX cross-section in FIG. 2), (b) A schematic cross-sectional view enlarging the main part of the power supply unit Top view of thermally conductive substrate in Embodiment 1 of the present invention Top view of thermally conductive substrate in Embodiment 2 of the present invention Sectional drawing of the power supply unit in Embodiment 2 of this invention (XX cross section of FIG. 3) Top view of thermally conductive substrate in Embodiment 3 of the present invention Sectional drawing of the power supply unit in Embodiment 3 of this invention (XX cross section of FIG. 5) Top view of the power supply unit in Embodiment 4 of the present invention Cross section of conventional power supply unit

Explanation of symbols

8 Power supply unit 9 Radiator 10 Thermally conductive substrate (base plate)
11 Circuit board 12 Transformer (heat generating component)
13A, 13B Power semiconductor elements (heat generating parts)
14 Control Element 15A, 15B Ventilation Part 16 Heat Transfer Plate 17 Insulating Layer 18 Conductor Pattern 18A Connection Terminal 19 Hole 20A, 20B Hole 21 Core Part 22 Coil Part 23 Middle Leg 24 Back Leg 25 Curved Surface 26 Projection Part

Claims (10)

A radiator,
A base plate attached to the radiator,
First and second heat generating parts surface-mounted on this base plate;
In a power supply unit that is electrically connected to the first and second heat generating components and includes a circuit board disposed at a position facing the base plate,
This power supply unit has
A first ventilation portion that is near the lower portion of the first heat-generating component and connects the lower side of the heat radiator and the component mounting surface side of the base plate;
A power supply unit formed with a second ventilation portion penetrating the circuit board near the top of the first heat-generating component. The circuit board has a hole;
In this hole, the upper part of the first heat generating component is inserted,
The power supply unit according to claim 1, wherein a gap between the first heat generating component and the circuit board in the hole is the second ventilation portion. The first ventilation part is
While being formed to penetrate the base plate and the radiator,
The power supply unit according to claim 1 or 2, wherein the first heat generating component and the second heat generating component are connected by the base plate. The first ventilation part is
The power supply unit according to claim 1, wherein the power supply unit is formed between the first heat generating component and the second heat generating component. The first ventilation part is
While being formed between the first heat generating component and the second heat generating component,
On the first ventilation part side of the second heat generating component,
The power supply unit according to claim 1, further comprising a connection terminal electrically connected to the circuit board. The first ventilation part is
3. The power supply unit according to claim 1, wherein the power supply unit is a part of a hole formed in the heat radiating body and the base plate in a lower part of the first heat generating component and in the vicinity thereof. The first ventilation part is
Consists of holes formed in the radiator and the base plate,
The power supply unit according to claim 1, wherein the hole formed in the base plate has a smaller opening area than the hole formed in the heat radiating body. The first ventilation part is
Consists of holes formed in the radiator and the base plate,
The hole formed in the base plate has a smaller opening area than the hole formed in the radiator,
The upper opening of the hole formed in the base plate is
Formed with a curved surface curved inward from the upper surface of the base plate toward the inner wall of the hole,
The power supply unit according to any one of claims 1 to 6, wherein the lower opening of the hole has a protrusion protruding downward. The base plate has a heat transfer plate joined to the heat radiating body, an insulating layer disposed on a part of the heat transfer plate, and a conductor pattern disposed on the insulating layer,
The first heat generating component is:
Mounted on the heat transfer plate,
The second heat generating component is
The power supply unit according to claim 1, wherein the power supply unit is mounted on the conductor pattern. The base plate is
A heat transfer plate joined on the heat dissipating body, an insulating layer disposed on a part of the heat transfer plate, and a conductor pattern disposed on the insulating layer;
The first ventilation part is
A part or all of the holes formed in the radiator,
The power supply unit according to claim 1, wherein the power supply unit is formed outward from the heat transfer plate.

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