JP2009188192A - Circuit equipment - Google Patents

Abstract

To provide a circuit device capable of efficiently dissipating heat of various components and members existing at positions separated from a heat dissipation board.
A plurality of circuit patterns (3) and a thermally conductive sheet member (4) arranged separately from the circuit pattern (3) are formed on an upper surface of an electrical insulating layer (2) on a heat dissipation substrate (1), and a separated circuit member 5 includes an electrical connection portion 51 that is electrically connected to the circuit pattern 3, a separation portion 52 that is spaced apart from the circuit pattern 3, and a connection portion 53 that connects the electrical connection portion 51 and the separation portion 52. Has been. A columnar or block-shaped heat conductive member 6 is installed between the separation portion 52 and the heat conductive sheet member 4.
[Selection] Figure 1

Description

  The present invention relates to a circuit device, and more particularly, to a circuit device provided with a separation circuit member that is provided apart from a heat dissipation board to install an electronic component.

  Recently, with the goal of developing a small and efficient circuit device that can efficiently flow a large current, thick and wide wiring materials and efficient electronic components are used, and a separate circuit section is provided at a position away from the board. In order to solve the above problems, heat-generating electronic components are installed there. However, in such a case, the development of a cooling structure is an effective issue for the circuit device.

  In order to solve such a problem, for example, in Patent Document 1 described later, a heat sink is provided in a wiring member such as a bus bar, and the wiring member is cooled to cool the heat-generating electronic components mounted on the wiring member. As a method for cooling the wiring member, for example, in Patent Document 2, the wiring member is cooled by tightening with a heat dissipation block via a heat dissipation region provided on the printed circuit board.

  The bus bar provided at a position away from the heat dissipation board and the exothermic electronic component mounted on the bus bar are generally difficult to cool. Therefore, at the junction between the exothermic electronic component and the bus bar, There is a problem that the thermal stress repeatedly applied is large and the fatigue of the joint portion between the heat-generating electronic component and the bus bar easily proceeds. In addition, a thermal stress is applied to the connection portion when the bus bar and the heat dissipation board are soldered, and the long-term stability of the joint portion is still a problem as described above.

  In the cooling structure of the heat generating electronic component of Patent Document 1, heat generated from the heat generating electronic component is radiated into the housing by fins provided on the bus bar. For this reason, heat is hidden in the housing and the heat-generating electronic components are not sufficiently cooled, and there is a problem in that the operation of other electronic components in the housing is adversely affected by an increase in the temperature in the housing. In particular, since the temperature of the soldered portion of the electronic component rises due to an increase in the temperature in the housing, thermal stress increases, which may affect the reliability of the soldered portion. On the other hand, in the cooling structure of the bus bar in Patent Document 2, since the high-current electronic components are arranged so as to be in contact with the heat dissipation block, there is a problem that the area of the circuit device becomes large and miniaturization is difficult.

Japanese Patent Laid-Open No. 10-135582 (page 2, lines 8-9, FIG. 2) Japanese Patent Laying-Open No. 2005-311262 (page 2, lines 1 to 12, line 1)

  An object of the present invention is to provide a circuit device that can efficiently dissipate the heat of various components and members existing at positions separated from a heat dissipation board in consideration of the above-described problems in the prior art.

  In order to solve the above problems, the present invention provides a heat dissipation board, an electrical insulating layer provided on one side of the heat dissipation board, a circuit pattern formed on the electrical insulating layer, a part of which is connected to the circuit pattern, and A spaced circuit member that is disposed apart from the circuit pattern and to which an electronic component is attached, a thermally conductive sheet member that is disposed on the electrical insulating layer and separated from the circuit pattern, the thermally conductive sheet member, and the above There is provided a circuit device including a heat conducting member disposed between a spaced circuit member.

  In other circuit devices as well as the circuit device of the present invention, an electrical insulating layer provided on one side of the heat dissipation board is necessary to prevent an electrical short circuit between the circuit pattern and the heat dissipation board. Since it is a thin layer body and has low thermal insulation, heat generated on the upper side of the electrical insulation layer is transmitted to the heat dissipation substrate via the electrical insulation layer and is radiated therefrom. On the other hand, in the present invention, the heat in the separation circuit member is transmitted to the heat radiating board through the heat conducting member, the heat conductive sheet member, and the electrical insulating layer in order, and is radiated from the heat radiating board. The In that case, in order to achieve a good thermal bond between the heat conducting member and the electrical insulating layer, a good mechanical bond between the two is necessary, but the presence of the heat conductive sheet member Greatly contribute to it. For example, the heat conductive sheet member and the heat conductive member can be easily and firmly bonded together by soldering while maintaining good heat conduction.

  In the following, among the various members included in the circuit device, the same members are denoted by the same reference numerals, and description thereof is omitted in FIG.

Embodiment 1 FIG.
FIG. 1 is a perspective view including a partial cross-sectional view of a circuit device according to Embodiment 1 of the present invention. In FIG. 1, an electrical insulating layer 2 is provided on a heat dissipation substrate 1, and a plurality of circuit patterns 3 and a thermally conductive sheet member arranged separately from the circuit patterns 3 on the upper surface of the electrical insulating layer 2. 4 is formed. The separation circuit member 5 corresponds to a bus bar in the prior art, and includes an electrical connection portion 51 that is electrically connected to the circuit pattern 3, a separation portion 52 that is spaced from the circuit pattern 3, and an electrical connection It is comprised from the connection part 53 which connects the part 51 and the separation | separation part 52. FIG. A column-shaped or block-shaped heat conductive member 6 is installed between the separation portion 52 and the heat conductive sheet member 4, and the terminal 71 of the heat-generating electronic component 7 is soldered or welded to the separation portion 52. It is connected. Further, the separation portion 52 and the heat conductive member 6, and the heat conductive member 6 and the heat conductive sheet member 4 are both soldered to improve heat transferability. On the circuit pattern 3, a relatively small surface-mounted electronic component 8 is usually mounted.

  The heat radiating substrate 1 and the heat conducting member 6 are made of a material having good heat conductivity, for example, a metal such as copper or aluminum, or ceramics, and the electric insulating layer 2 is a heat resistant electric insulating material, for example, cured epoxy. It is made of resin, cured epoxy resin with glass fiber, silicon resin with glass fiber, or the like. Since the heat generating electronic component 7 is mounted on the separation circuit member 5 in addition to heat conductivity and electrical conductivity, a certain degree of mechanical strength is required. Therefore, these three characteristics are excellent in materials such as copper. , And metals such as aluminum, or non-metallic materials such as carbon and graphite. The heat conductive sheet member 4 is required to have good heat transfer properties, but in addition to ensuring heat transfer properties with the heat transfer member 6, soldering such as copper can be performed easily and reliably. It is preferably made of a possible material. A surface mount component 8 such as a MOSFET or an electrolytic chip capacitor is mounted on the circuit pattern 3, and a semiconductor element such as a transistor or a diode, or a heat generating property such as a reactor or a capacitor is mounted on the separation portion 52. An electronic component 7 is mounted. Further, a heat sink (not shown) is attached to the back surface of the heat dissipation substrate 1 as necessary.

  The heat conductive member 6 is first erected by soldering to the heat conductive sheet member 4, and then the separation portion 52 of the separation circuit member 5 is placed on the top surface of the heat conduction member 6 and screwed or soldered. Fixed. If this soldering is performed during the soldering operation between other members, the efficiency of the assembly operation of the circuit device of the first embodiment is improved.

  Although each thickness of the thermal radiation board | substrate 1, the electrical insulation layer 2, and the heat conductive sheet member 4 changes with the magnitude | sizes of the circuit apparatus of Embodiment 1, generally the thermal radiation board 1 is 1-5 mm, an electrical insulation layer 2 and the heat conductive sheet member 4 are 50 micrometers-200 micrometers. As shown in FIG. 1, there are usually a plurality of circuit patterns 3 and a plurality of thermally conductive sheet members 4 on one side of the electrical insulating layer 2. Therefore, the heat conductive sheet member 4 has an advantage that it can be formed at the same time as the circuit pattern 3 is formed. When, for example, an epoxy resin is employed as a material for forming the electrical insulating layer 2, the heat dissipation substrate 1, the epoxy resin sheet having a predetermined thickness, the circuit pattern, and the metal layer that becomes the heat conductive sheet member are pressed and fixed. A desired number of circuit patterns 3 and a desired number of heat conductive sheet members 4 are formed on each side at predetermined locations by a normal etching technique, and circuit patterns and heat radiation sheet members scattered in an island shape are manufactured.

  Generally, when a large heat-generating electronic component 7 is mounted, the area of the heat dissipation substrate 1 is remarkably increased, and the circuit device is increased in size. With respect to this problem, in the first embodiment, the heat-generating electronic component 7 is mounted on the separation circuit member 5 provided in the space above the heat dissipation substrate 1, and between the separation circuit member 5 and the electrical insulating layer 2. By mounting the surface-mounted electronic component 8 having a relatively small shape in the space, it is possible to suppress the area expansion of the heat dissipation board 1 and to reduce the size of the entire circuit device. Further, most of the large current path flowing through the surface-mounted electronic component 8, the plurality of relatively thin circuit patterns 3 on the electrical insulating layer 2, and the heat-generating electronic component 7 is constituted by the separation circuit member 5. As a result, the heat dissipation performance can be improved and the electrical loss can be reduced, so that the efficiency of the circuit device can be increased. At that time, the electrical connection portion 51 of the separation circuit member 5 is preferably connected near the surface-mounted electronic component 8 on the circuit pattern 3, preferably at an adjacent position.

  With the above configuration, the heat generated in the separation circuit member 5 and the heat generating electronic component 7 is transmitted to the heat dissipation substrate 1 via the heat conductive member 6 and the heat conductive sheet member 4, and from there. For example, since heat is radiated to the outside of the circuit device, the separated circuit member 5 and the heat generating electronic component 7 can be efficiently cooled. In addition, when solder is used to join the separation circuit member 5 and the heat-generating electronic component 7, thermal stress between the two due to the power cycle is dispersed, and the reliability of the joint is improved. Further, since the mechanical stress due to vibration is dispersed in addition to the thermal stress at the solder joint between the two, the reliability of the joint between the separation circuit member 5 and the circuit pattern 3 is also improved.

  Further, a cooling device such as a heat sink (not shown) is attached to the heat dissipation board 1 of the circuit device of the first embodiment. A circuit composed of a surface mount component, a heat generating component, a heat dissipation board, and the like is housed in a housing in order to protect it from the outside of the corridor device. By exposing the cooling device to the outside of the housing, heat can be dissipated into the housing even when the heat-generating component is located away from the heat-radiating substrate inside the housing, compared to the cooling structure of Patent Document 1. The thermal influence on other electronic components in the housing can be reduced. Furthermore, since no current flows through the heat conducting member 6, it is installed in an arrangement in which the resistance of each current and heat is reduced by separating the connecting portion and the heat conducting member as compared with the cooling structure of Patent Document 2. Can do. Therefore, the current path length of the separation circuit member 5 can be shortened, and the electrical loss can be reduced. When a thick prismatic material or block material as shown in FIG. 1 is used as the heat conducting member 6, the separation circuit member 5 is firmly fixed to the heat dissipation substrate 1, so that the circuit device has good earthquake resistance and reliability. Will improve.

  1 shows an example in which one heat conducting member 6 is provided for one separated circuit member 5, a plurality of heat conducting members 6 may be provided for one separated circuit member 5. By adopting a thick prismatic material or the like as shown in FIG. 1 as the heat conducting member 6, its thermal resistance can be reduced and the heat radiation performance is improved.

  In the first embodiment, by mounting a plurality of heat generating electronic components 7 on one separated circuit member 5, the number of installed separated circuit members can be reduced. be able to. In this case, if a plurality of heat conducting members 6 are installed so as to be close to each of the plurality of heat generating electronic components 7, each heat radiation from the plurality of heat generating electronic components 7 is efficiently transmitted to the heat dissipation substrate 1. be able to. Moreover, the entire area of the heat dissipation substrate 1 can be effectively utilized by disposing and installing the plurality of heat conducting members 6.

Embodiment 2. FIG.
FIG. 2 is a perspective view including a partial cross-sectional view of the circuit device according to Embodiment 2 of the present invention. In FIG. 2, in each of the heat generating electronic components 7a and 7b, each end of the terminal 71a extending from the left surface in FIG. 2 is connected to the separation portion 52a of the separation circuit member 5a by welding or soldering. Further, the lower surfaces of the heat-generating electronic components 7a and 7b are placed so as to be in contact with the separation portion 52a of the separation circuit member 5a through a heat-conductive insulating material 9 such as silicone grease. One end of a terminal 71 extending from the right surface of 7a is connected to the right surface of the heat generating electronic component 4b by welding or soldering, and one end of the terminal 71b extending from the right surface of the heat generating electronic component 7b is connected to the separation circuit member 5b. The spacer 52b is connected by welding or soldering.

  According to the second embodiment, the heat generated from the heat-generating electronic components 7a and 7b is generated not only from the terminals 71 but also from the bottom of the heat-generating electronic components 7a and 7b through the insulating material 9 having good heat conductivity. However, since it is transmitted to the heat conducting member 6 through the separation circuit member 5, the heat generating electronic components 7a and 7b can be cooled more efficiently. In the second embodiment, the separation circuit member 5a, different types of exothermic electronic components 7a and 7b, and the separation circuit member 5b are connected in series, and the exothermic electronic component 7a, 7b is connected to the terminals 71a and 71b, the amount of heat released from the electrical terminal 71 on one side only to the separated circuit member 5 is increased. Since heat can be transferred to the heat conducting member 6, thermal stress at the connection portion of the terminal 71 can be reduced. Further, if the terminals 71a and 71b can be directly connected to each other, the circuit wiring can be shortened, the mounting area of the electronic component can be increased and the size can be reduced, and the circuit loss can be reduced. Increases efficiency. The heat generating electronic component 7 can be firmly supported by using an adhesive with high heat dissipation, for example, a silicone adhesive or an epoxy adhesive in which a filler is mixed in a resin, instead of the silicone grease. The vibration resistance of the device is improved.

Embodiment 3 FIG.
FIG. 3 is a perspective view including a partial cross-sectional view of the circuit device according to Embodiment 3 of the present invention. As can be seen from the comparison between FIG. 3 and FIG. 1, in the third embodiment, the one in which the separation circuit member 5 and the heat conducting member 6 in the first embodiment are integrally formed is used. However, unlike the first embodiment, the other configurations are essentially the same. That is, the separation circuit member 5 in the third embodiment has a conductive portion 54 corresponding to the heat conductive member 6, and the lower end portion of the conductive portion 54 is soldered to the heat conductive sheet member 4. Further, the conductive portion 54 is formed at the same time when the separated circuit member 5 is manufactured by punching or bending. The portion of the heat conducting portion 54 connected to the heat conductive sheet member 4 is bent into an L shape as shown in the figure, and the lower surface of the bent portion is soldered to the heat conductive sheet member 4. .

  The heat conducting portion 54 is not a block shape as described in the first embodiment, but is formed of the same plate-like body as the separating portion 52 and the connecting portion 53 of the separating circuit member 5, but they are integrally formed. Therefore, there is no screw fastening portion, and the effect of reducing thermal resistance due to the absence of contact thermal resistance due to screw fastening is great, and the separation circuit member 5 and the heat-generating electronic component 7 can be cooled more efficiently. Moreover, since the number of parts can be reduced, it is excellent in cost and productivity. The thickness of the plate-like body constituting the heat conducting portion 54 may be the same as the thickness of the plate-like body constituting the separating portion 52 and the connecting portion 53, and the dimension is to achieve an effective heat transfer function. It is said.

  Further, when both the electrical connection portion 51 and the heat conducting portion 54 of the separation circuit member 5 are plate-shaped, as shown in FIG. 3, if the two wide surfaces are formed so that their directions are orthogonal to each other, the separation circuit member 5 is separated. The rigidity of each direction of the circuit member 5 is improved, and the vibration resistance is improved. Furthermore, when the separation circuit member 5 includes a plurality of electrical connection portions 51 and a plurality of heat conduction portions 54, the directions of the wide surfaces are orthogonal to each other in the plurality of electrical connection portions 51 and the plurality of heat conduction portions 54. If formed in this way, the same effect as described above can be obtained.

Embodiment 4 FIG.
FIG. 4 is a perspective view including a partial cross-sectional view of the circuit device according to Embodiment 4 of the present invention. In FIG. 4, each of the plurality of separated circuit members 5 is insert-molded in the housing 10 and soldered to the circuit pattern 3 on the electrical insulating layer 2, and the separated circuit member 5 and the heat conducting member 6 are screwed. It is joined by a stopper. Further, the heat generating electronic component 7 is joined to the separation circuit member 5 by welding or soldering.

  In the fourth embodiment, the separation circuit member 5 and the heat conducting member 6 that are integrally formed as the separation circuit member 5 in the third embodiment may be insert-molded in the housing 10. . By insert-molding the plurality of spaced circuit members 5 into the housing 10, the spaced circuit members 5 can be more firmly fixed to the housing 10 against vibrations and temperature changes, thereby further improving the reliability of the circuit device. be able to. Further, even if a relatively heavy reactor or the like is mounted on the separation circuit member 5, high reliability can be obtained, and the mountability can be improved.

Embodiment 5 FIG.
FIG. 5 is a side view including a partial cross-sectional view of the circuit device according to Embodiment 5 of the present invention. The fifth embodiment is different from the first to third embodiments in that the exothermic electronic component 7, the separation circuit member 5, and the heat conducting member 6 are preliminarily connected and assembled, and then molded together with resin. However, it is different from the resin mold unit 11 and other configurations are the same. The resin mold unit 11 is soldered and mounted on the circuit pattern 3 and the heat conductive sheet member 4 on the electrical insulating layer 2. In addition, as in the third embodiment, the one in which the separation circuit member 5 and the heat conducting member 6 are integrally molded may be resin molded.

  By resin molding, heat generated from the heat-generating electronic component 7 and the separation circuit member 5 in the resin mold unit 11 is dispersed in the resin mold unit 11 and is radiated from the heat dissipation substrate 1 through the heat conducting member 6. When incorporated in the casing, heat is not easily dissipated in the casing, so that the thermal influence on other electronic components and devices in the casing can be further reduced. Furthermore, the vibration resistance reliability of the heat-generating electronic component 7 can be improved, and the unit can be mounted on the heat dissipation substrate 1 by forming a unit.

  The present invention is likely to be used in the field of various circuit devices.

It is a perspective view including the partial cross section figure of the circuit device in Embodiment 1 of this invention. It is a perspective view including the partial cross section figure of the circuit device in Embodiment 2 of this invention. It is a perspective view including the partial cross section figure of the circuit device in Embodiment 3 of this invention. It is a perspective view including the partial cross section figure of the circuit device in Embodiment 4 of this invention. It is a side view including the partial cross section figure of the circuit device in Embodiment 5 of this invention.

Explanation of symbols

1: heat dissipation substrate, 2: electrical insulation layer, 3: circuit pattern, 4: thermally conductive sheet member,
5: separation circuit member, 51: electrical connection part, 52: separation part, 53: connection part, 54: heat conduction part,
6: heat conduction member, 7: exothermic electronic component, 71: terminal, 8: surface mount electronic component,
9: Insulating material, 10: Housing, 11: Resin mold unit.

Claims (7)

  A heat dissipation board, an electrical insulating layer provided on one side of the heat dissipation board, a circuit pattern formed on the electrical insulation layer, a part of which is connected to the circuit pattern and spaced apart from the circuit pattern, and an electronic component A thermally conductive sheet member disposed on the electrical insulating layer separately from the circuit pattern, and a heat conduction member disposed between the thermally conductive sheet member and the spaced circuit member. A circuit device comprising: a member.   The separation circuit member includes a circuit pattern connection portion connected to the circuit pattern, a separation portion separated from the circuit pattern, and the heat conducting member is formed integrally with the separation portion. The circuit device according to claim 1.   3. The circuit device according to claim 1, wherein one or both of the separation circuit member and the heat conduction member are insert-molded in a housing that houses the circuit device. 4.   4. The circuit device according to claim 1, wherein the heat conductive sheet member is formed on the electrical insulating layer when the circuit pattern is formed. 5. .   5. The circuit device according to claim 2, wherein the electronic component is connected to the separation portion or the heat conductive member via a heat conductive electrical insulating material. .   The circuit device according to any one of claims 1 to 5, wherein the separation circuit member, the electronic component, and the heat conducting member are integrated by a resin mold.   The circuit according to any one of claims 1 to 6, wherein a radiation fin or a cooling device that is exposed to the atmosphere is provided on a side opposite to the electrical insulating layer side of the radiation board. apparatus.

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