The present invention relates to a circuit assembly and an electrical junction box.
Conventionally, circuit assemblies in which a circuit board and a heat discharging member that discharges heat of the circuit board to the outside are stacked on each other are known. In this type of circuit assemblies, the circuit board is adhered to the heat discharging member with an adhesive agent. JP 2005-151617A discloses a circuit assembly in which a sheet-shaped component obtained by braiding insolation fibers into a sheet is laid on an adhesive agent that is applied to a heat discharging member so that the adhesive agent passes substantially uniformly through the entire sheet-shaped component. A circuit structure is laid on this sheet-shaped component and is pressed towards the heat discharging member side, thus fixing it to the heat discharging member.
Meanwhile, in JP 2005-151617A in which the circuit structure is pressed towards the heat discharging member side when being fixed to the heat discharging plate, if the distance between a circuit board and the heat discharging member is not kept constant, there is a risk that the pressure that acts on the adhesive agent via the circuit structure when it is pressed may become non-uniform, and defects may occur such as locations where adhesion with the adhesive agent is insufficient. On the other hand, if a jig is used to keep the distance between the circuit board and the heat discharging member constant, there is the problem that a cost will be incurred for the jig.
JP 2014-82844A discloses an electrical junction box provided with a circuit unit on which electronic components are mounted, a heat discharging member that discharges heat of the circuit unit, and a frame-shaped member that is disposed on the heat discharging member and accommodates the circuit unit. The frame-shaped member has compartments into which the electronic components are accommodated, and holds the electronic components in their positions.
Here, if a spacer for keeping the distance between the circuit board and the heat discharging member constant is provided between the circuit structure and the heat discharging member in order to solve the problems of JP 2005-151617A, it is not preferable to provide, in addition to the spacer, a frame-shaped member for holding electronic components in positions as disclosed in JP 2014-82844A because this will lead to an increase in the number of components and complication of the structure.
The present invention was made in view of the above-described circumstances, and it is an object thereof to hold a part of a circuit unit at a predetermined position while keeping the distance between a circuit board and a heat discharging member constant, with a simple configuration.
According to the present invention, a circuit assembly includes: a circuit unit that includes an electrically conducting path on which electronic components are mounted; a heat discharging member that is placed on the circuit unit, and is configured to discharge heat of the circuit unit; and a spacer that is disposed between the circuit unit and the heat discharging member, wherein the spacer is provided with a main portion that is disposed between the circuit unit and the heat discharging member, and an accommodating portion that accommodates a part of the circuit unit.
According to the present invention, since the main portion of the spacer is disposed between the circuit unit and the heat discharging member, it is possible to keep the distance between the circuit unit and the heat discharging member constant without using a jig. Furthermore, since the accommodating portion of the spacer accommodates a part of the circuit unit, it is possible to hold that part of the circuit unit at a predetermined position using the structure of the spacer, instead of providing a separate member for accommodating a part of the circuit unit. Accordingly, it is possible to hold a part of the circuit unit at a predetermined position while keeping the distance between the circuit board and the heat discharging member constant, with a simple configuration.
The embodiments of the present invention may have following aspects:
The main portion and the accommodating portion may be molded in one piece using a resin.
With this, it is possible to simplify the configuration compared to a case where, for example, a separate accommodating portion is fixed to the main portion to form a spacer.
The accommodating portion may accommodate an external connection terminal of the circuit unit.
The accommodating portion may accommodate a coil of the circuit unit.
The accommodating portion may accommodate a nut of the circuit unit.
The main portion may be provided with a through hole that is formed through the main portion, and a heat transmission portion that is arranged in the through hole, and is configured to transmit heat of the circuit unit to the heat discharging member.
With this, the heat transmission portion allows heat of the circuit unit to be discharged from the heat discharging member.
The circuit unit and the heat discharging member may be fastened to each other with screws.
With this, the circuit unit and the heat discharging member can be fixed to each other firmly with the screws, while the spacer receives a force acting when the circuit unit and the heat discharging member are fastened to each other with the screws.
An electrical junction box is provided with the above-described circuit assembly.
According to the present invention, it is possible to hold a part of a circuit unit at a predetermined position while keeping the distance between a circuit board and a heat discharging member constant, with a simple configuration.
Hereinafter, Embodiment 1 will be described with reference to
An electrical junction box 10 is arranged on, for example, an electric power supplying path between a power supply such as a battery of a vehicle, and loads including an in-car electric component, such as a lamp or a wiper, and a motor, and can be used, for example, for a DC-DC converter, an inverter, or the like. In the description below, “upward” and “downward” are based on the directions in
As shown in
As shown in
The circuit unit 20A is provided with a circuit board 21 with an electrically conducting path, and electronic components 26 that are mounted on the electrically conducting path. The circuit board 21 is rectangular as shown in
The electronic components 26 are mounted on the circuit board 21 as shown in
The coil 27 includes a magnetic material core 27A and the coil wire 27B. The coil wire 27B is obtained by winding a flat rectangular copper wire that has a rectangular cross section in a so-called edgewise manner. The coil wire 27B has, at the respective ends thereof, passage holes 27C that are formed through the coil wire 27B, and are electrically connected to the terminal portions 25B by inserting the shaft portions of screws 38 (bolts) into the passage holes 25C and 27C, and fastening nuts 39 to the screws 38.
The heat discharging member 28 is made of a metal material such as aluminum or an aluminum alloy that is molded using aluminum die casting for example, or another material. As shown in
The mounting portion 29 has a flat upper surface. The mounting portion 29 has, at positions on the edge side of the mounting portion 29, a plurality of screw holes 31A for screwing screws, a plurality of positioning holes 31B for positioning the spacer 40, and a clearance recess 31C. An end of a terminal (not shown) that is inserted into a through hole of the circuit board 21 is arranged in the clearance recess 31C. The mounting portion 29 has recesses 32A and 32B at positions that correspond to the coil 27 (not shown) and the stud bolt 56.
In a state in which the spacer 40 and the circuit board 21 are stacked on the mounting portion 29, the peripheral wall portion 33 is higher than the upper end of the circuit board 21. The peripheral wall portion 33 is divided at positions that correspond to connector portions 17B and 54, and the connector terminals 24. The boss parts 34 with a screw hole protrude outward from the outer side of the peripheral wall portion 33.
The spacer 40 is a rectangular insulating plate having such a thickness that it is not easily bent, and is mounted on the entire upper surface of the heat discharging member 28. As shown in
The main portion 40A is provided with a plurality of (fourteen in the present embodiment) through holes 41 that are formed through the main portion 40A, screw passage holes 42A and 42B through which the shaft portions of the screws 48 pass, a terminal passage hole 43, positioning projections 44A and 44B, and engaging projections 45.
Each through hole 41 is circular in the shape of a true circle, and is formed through the spacer 40 so as to be able to accommodate a heat transmission portion 47 that transmits heat of the circuit unit 20A to the heat discharging member 28. Two or four through holes 41 are lined up in a plurality of lines arranged at equal intervals (intervals in a left-right direction of
For the heat transmission portions 47, members are used that have a high heat conductivity, and that may be, for example, a thermosetting or thermoplastic adhesive agent, an adhesive sheet obtained by applying an adhesive agent to a base material, a heat discharging grease, a heat radiation gel, a heat conduction sheet, or the like. When an adhesive agent is used, a mixture of two types of epoxy adhesive agents that solidifies at room temperature may be used, for example. Alternatively, for example, an insulating film made of a synthetic resin to both surfaces of which an insulating adhesive agent is applied may be used. The heat transmission portion 47 is arranged overlapping, on its upper side, with at least a part of the electronic component 26, and heat of the electronic component 26 transmitted to the heat transmission portion 47 is discharged from the heat discharging member 28.
The screw passage holes 42A and 42B are formed at positions close to the peripheral edge of the spacer 40. The terminal passage hole 43 is formed through the spacer 40 in a rectangular shape. The positioning projections 44A and 44B are columnar, and are arranged at positions close to the corners on the peripheral edge of the spacer 40. The positioning projections 44A project upward from the upper surface of the spacer 40 in a columnar shape, and the positioning projections 44B project, as shown in
The engaging projections 45 can engage with portions that are contiguous with the connector terminals 24. As shown in
As shown in
The nut accommodating portions 51 are formed as recesses formed in the flat extended portion 50, and have a shape that corresponds to the rectangular nuts 39 so as to prevent the nuts 39 from rotating. Each nut accommodating portion 51 has, on the bottom surface thereof, a hole 51A that is formed through the flat extended portion 50, and whose diameter is reduced stepwise, so that the front end of the screw 38 can be passed therethrough.
The coil accommodating portion 52 has a bottom portion 52A that is recessed further downward than the flat extended portion 50, and a wall portion 52B that has the shape of a rectangular tube that encloses the entire periphery of the coil 27. The bottom portion 52A is fitted into the recess 32A of the heat discharging member 28. The wall portion 52B has substantially the same height as the coil 27 accommodated in the coil accommodating portion 52. The wall portion 52B is divided at positions from which the coil wire 27B is drawn.
As shown in
A separate auxiliary member 60 is arranged in the vicinity of the coil accommodating portion 52 and the terminal accommodating portion 53. As shown in
As shown in
As shown in
The following will describe a method for manufacturing the circuit assembly 20 and the electrical junction box 10.
The spacer 40 is mounted on the mounting portion 29 that is the upper surface of the heat discharging member 28 (
Solder paste is added to the electrically conducting path of the circuit board 21 that is obtained by adhering the printed board 21A and the busbar board 21B to each other using an adhesive member, the electronic components 26 are arranged at predetermined positions, and the resulting object is passed through a reflow furnace to be subjected to reflow soldering. Thereby, the circuit unit 20A in which the electronic components 26 are mounted on the circuit board 21 is achieved.
Then, by inserting the connector terminals 24 of the circuit unit 20A into the terminal insertion holes 54D of the connector portion 54, the circuit unit 20A is mounted on the spacer 40 (
Then, the coil 27 is accommodated in the coil accommodating portion 52, and the ends of the coil wire 27B and the terminal portions 25B of the circuit unit 20A are fastened to each other with the screws 38 and the nuts 39. Furthermore, the stud bolt 56 is accommodated in the terminal accommodating portion 53, and the connection plate 55 is mounted. Furthermore, the screws 48 are inserted into the screw holes 22, the screw passage holes 42A and 42B, and the screw holes 31A, and are screwed to fix the circuit board 21 and the heat discharging member 28 to each other, thereby achieving the circuit assembly 20 (see
According to the present embodiment, the following functions and effects can be attained.
According to the present embodiment, since the main portion 40A of the spacer 40 is disposed between the circuit unit 20A and the heat discharging member 28, it is possible to keep the distance between the circuit unit 20A and the heat discharging member 28 constant without using a jig. Furthermore, since the accommodating portions 51 to 54 of the spacer 40 accommodate a part (the nuts 39, the coil 27, the stud bolt 56, and the connector terminals 24) of the circuit unit 20A, it is possible to hold parts of the circuit unit 20A at predetermined positions using the structure of the spacer 40, instead of providing a separate frame-shaped resin member for accommodating parts of the circuit unit 20A. Accordingly, it is possible to hold parts of the circuit unit 20A at predetermined positions while keeping the distance between the circuit board 21 and the heat discharging member 28 constant, with a simple configuration.
Furthermore, the main portion 40A and the accommodating portions 51 to 54 are molded in one piece using a resin.
With this, it is possible to simplify the configuration compared to a case where, for example, a separate accommodating portion is fixed to the main portion 40A to form a spacer.
Furthermore, the accommodating portions 51 to 54 accommodate the nuts 39 of the circuit unit 20A.
With this, by providing the nut accommodating portions 51 obtained by reducing the thickness of the spacer 40 locally, it is possible to hold the nuts 39 in positions, and thus it is possible to simply the configuration for holding the nuts 39 in positions.
Furthermore, the main portion 40A is provided with through holes 41 that are formed through the main portion 40A, and heat transmission portions 47 that are arranged in the through holes 41, and are configured to transmit heat of the circuit unit 20A to the heat discharging member 28.
With this, the heat transmission portions 47 allow heat of the circuit unit 20A to be discharged from the heat discharging member 28.
Furthermore, the circuit unit 20A and the heat discharging member 28 are fastened to each other with screws 48.
With this, the circuit unit 20A and the heat discharging member 28 can be fixed to each other firmly with the screws 48, while the spacer 40 receives a force acting when the circuit unit 20A and the heat discharging member 28 are fastened to each other with the screws.
The present invention is not limited to the embodiment explained in the foregoing description given with reference to the drawings, and the technical scope of the present invention encompasses, for example, the following embodiments.
(1) The parts of the circuit unit 20A that are accommodated by the spacer 40 are not limited to the above-described nuts 39, coil 27, stud bolt 56, and connector terminals 24, and may be other components of the circuit unit.
(2) The material of the heat discharging member 28 is not limited to aluminum or an aluminum alloy, and may be any material as long as it is a metal material that has high heat conductivity. For example, the heat discharging member 28 may be made of copper or a copper alloy.
(3) Although the circuit unit 20A and the heat discharging member 28 are fastened to each other with the screws 48, the circuit unit 20A and the heat discharging member 28 may be fixed to each other using a fixation means (for example, a lock mechanism) other than the screws.
Number | Date | Country | Kind |
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2014-258909 | Dec 2014 | JP | national |
This application is the U.S. national stage of PCT/JP2015/084121 filed Dec. 4, 2015, which claims priority of Japanese Patent Application No. JP 2014-258909 filed Dec. 22, 2014.
Filing Document | Filing Date | Country | Kind |
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PCT/JP2015/084121 | 12/4/2015 | WO | 00 |