JP6079558B2 - Circuit structure - Google Patents

Description

  The present invention relates to a circuit structure.

  2. Description of the Related Art Conventionally, as a device that performs energization or disconnection of an in-vehicle electrical component, a device in which a circuit structure including a circuit board on which various electronic components are mounted is accommodated in a case is known.

  As such a device, for example, a power conversion device such as a DC-DC converter that converts an input DC voltage into a predetermined level of DC voltage and outputs the same is proposed. Since such a power conversion device handles a large current, a metal material such as a bus bar is often used as a circuit routing material. Among them, a configuration has been proposed in which a circuit is miniaturized by using a jumper wire when connecting bus bars.

JP-A-11-220823

  However, when a jumper wire is used in a circuit that allows a large current to flow, such as a DC-DC converter device, a large number of development man-hours are required such as the development of a jumper wire that can handle a large current and the development of mounting technology. In addition, if special jumper wires are used, the cost of parts increases. Furthermore, the use of jumper wires leads to an increase in the number of parts and work man-hours.

  The present invention has been completed based on the above circumstances, and an object of the present invention is to provide a small and simple circuit structure having a small number of parts.

The present invention includes a board having a through-hole for connection, a plurality of bus bars provided on one side of the board and constituting a power circuit, a main body portion, and a pair of lead terminals, and the lead terminals are used for the connection. And a coil mounted on the other side of the substrate by being connected to the bus bar exposed through the through hole, wherein the plurality of bus bars include a first bus bar, a second bus bar, and a second bus bar. A bus bar; and a third bus bar, wherein the first bus bar and the second bus bar are connected to each other by the pair of lead terminals of the coil, and the third bus bar is the main body portion of the coil and in the region of the corresponding substrate, wherein are first arranged on the bus bar and the second bus bar and the different regions, for heat dissipation in the region of the substrate corresponding to the main portion of the coil It has a feature where the through holes are provided.

  According to the above-described present invention, the connection between the bus bars is performed using the existing coil that is originally used for the circuit structure instead of the jumper wire, so that the number of parts can be reduced and the assembly work can be performed. It can be simplified. In addition, a configuration in which the third bus bar is arranged in a vacant area (a part of an area corresponding to the main body of the coil) around the first bus bar and the second bus bar generated by using a coil larger than the jumper wire. By doing so, waste of space can be eliminated and a high-density circuit structure can be obtained.

Moreover, since the heat generated from the coil is transmitted to the region corresponding to the main body portion of the third bus bar through the heat radiating through-hole, the third bus bar can efficiently dissipate heat.

  Moreover, it is good also as a structure which arrange | positions a heat-transfer sheet | seat between the main-body part of a coil, and the 3rd bus bar exposed by the through-hole for heat radiation. With such a configuration, the heat generated from the coil is more easily transmitted to the third bus bar, and the heat dissipation effect is improved.

  Furthermore, it is good also as a structure which distributes a heat sink on the surface on the opposite side to the surface facing the board | substrate of a some bus bar. With such a configuration, the heat dissipation effect is further improved.

  According to the present invention, a small circuit structure can be obtained with a small number of parts and a simple structure.

The exploded perspective view of the DC-DC converter device of one embodiment Plan view of DC-DC converter device Front view of DC-DC converter device Right side view of the DC-DC converter device Plan view of a state in which the power circuit board is housed in the frame The top view which shows the positional relationship of a bus-bar and a coil AA sectional view of FIG. Expanded cross-sectional view of the main part of the connection between the bus bar and the coil

  The apparatus 10 provided with the circuit structure 30 of one Embodiment is demonstrated referring FIG. 1 thru | or FIG. The device 10 of the present embodiment is a DC-DC converter device 10 mounted on a vehicle (not shown) or the like. In the following description, the upper side in FIG. 3 is the upper side, the lower side is the lower side, the right side is the right, and the left side is the left.

  As shown in FIG. 1, the DC-DC converter device 10 according to the present embodiment includes a circuit configuration body 30 including a power circuit board 31, a control circuit board 35, and a plurality of bus bars 33, and heat generated in the circuit configuration body 30. A heat sink 40 for radiating heat, a shield cover 45, and a case 11 for housing them.

(Case 11)
The case 11 is made of a synthetic resin or the like, and includes an upper cover 12, a frame 20, and an under cover 25 as shown in FIG.

  The frame 20 is a frame having a substantially rectangular shape, and is formed in a size that can accommodate the circuit component 30 (see FIG. 5). Further, on the left side in FIG. 2, a support wall 21 having a substantially U-shaped cross section for supporting the three external connection terminals 33 </ b> F led out from the circuit structure 30 from the lower side is extended.

  The upper cover 12 has a shallow dish shape that is assembled so as to cover the upper portion of the frame 20. More specifically, the upper cover 12 includes a rectangular top plate portion 13 and four side wall portions 14 extending downward from four sides of the top plate portion 13. An insertion hole 16 for inserting a breathable waterproof valve 15 capable of adjusting the internal pressure of the case is provided at the center of the top plate portion 13. Further, from all the side wall portions 14, locking pieces 17 that are locked to locking protrusions 22 provided on the outer peripheral wall of the frame 20 are extended downward two by two.

  The under cover 25 is a plate-like member, and two opposing sides on the short side of the rectangular bottom wall portion 26 are vertically bent upward to form a vertical portion 27. These vertical portions 27 are screwed to side surfaces 42 of a heat sink 40 described later. The bottom wall portion 26 is provided with a plurality of recesses 28 intermittently along the long side direction. The under cover 25 functions as a rectifying plate for air flowing between the fins 41 of the heat sink 40 described later.

(Circuit structure 30)
The circuit structure 30 includes a power circuit board 31 and a control circuit board 35, a plurality of electronic components 32 mounted on the front surface side (upper side in FIG. 1) of the power circuit board 31, and the back surface side (see FIG. 1 is provided with a plurality of bus bars 33 arranged and bonded to the lower side and a heat equalizing plate 36 disposed between the power circuit board 31 and the control circuit board 35.

  The power circuit board 31 has a rectangular shape that can be accommodated in the frame 20. A conductive path (not shown) is formed on the front surface by a printed wiring technique, and a plurality of bus bars 33 are arranged in a predetermined pattern on the back surface. Measured and bonded (see Fig. 6). As shown in FIG. 5, a plurality of through holes 34 (an example of connection through holes and heat dissipation through holes) are provided at appropriate positions on the power circuit board 31. These through holes 34 are for mounting the electronic component 32 on the bus bar 33, and the electronic component 32 is connected to the surface of the bus bar 33 exposed from the through hole 34 by a known method such as soldering. Yes.

  The control circuit board 35 is a plate-like member having a substantially L shape as shown in FIG. 1, is arranged substantially in parallel with the power circuit board 31, and is connected to the power circuit board 31 by the relay terminal 43. .

  Further, in a partial region between the circuit boards 31 and 35, a heat equalizing plate 36 made of a metal plate is disposed substantially parallel to the circuit boards 31 and 35, and is mounted on the power circuit board 31. The heat generated from the electronic component 32 prevents the circuit component 30 from becoming locally hot.

  The circuit configuration body 30 of the present embodiment is a DC-DC converter. The DC-DC converter is a circuit that converts a direct-current voltage into a different direct-current voltage, and is provided to supply power to various vehicle loads in, for example, environment-friendly vehicles such as HEV vehicles and EV vehicles.

  A well-known circuit configuration can be used for the DC-DC converter, and the electronic component 32 configuring the DC-DC converter includes, for example, a switching element such as a resistor, a coil 320, a capacitor, and a MOSFET. The terminals of these electronic components 32 are all surface-mounted, and are connected to the bus bars 33 exposed in the through holes 34 of the power circuit board 31 by a method such as soldering as described above.

(Heat sink 40)
A heat sink 40 is disposed below the circuit structure 30. The heat sink 40 is a heat radiating member made of a metal material having excellent thermal conductivity such as aluminum or aluminum alloy, and has a function of radiating heat generated in the circuit component 30. The upper surface of the heat sink 40 has a flat plate shape, and a plurality of fins 41 extending downward are formed on the lower surface. Further, the opposing side surface 42 on the short side is plate-like and is integrated with the vertical portion 27 of the under cover 25 by screws (not shown).

  Note that the lower surface of the circuit component 30 (the lower surface of the bus bar 33) and the upper surface of the heat sink 40 are fixed to each other by an insulating heat conductive adhesive 38 (see FIG. 8).

(Shield cover 45)
The upper side of the circuit structure 30 is covered with a shield cover 45. The shield cover 45 is made of, for example, galvanized steel (made of metal), and is formed in a substantially rectangular shallow dish shape that is slightly smaller than the upper cover 12. A concave portion 47 is formed in the central portion of the top plate portion 46 so as not to interfere with the breathable waterproof valve 15 attached to the upper cover 12 so that the unit is lowered. Further, three of the four side wall portions 48 are provided with a fixed piece 49 having an L-shaped cross section facing downward, and the tip 49A is fixed near the edge of the heat sink 40 with a screw. .

  In the present embodiment, when the bus bars 33 are connected to each other, a coil 320, which is an existing electronic component 32 that is originally used, is used in place of the conventionally used jumper wire. The coil 320 of the present embodiment is a surface mount type coil (SMD coil), and has a rectangular parallelepiped main body 321 whose upper surface is flat, and the edges of two opposing sides of the bottom surface of the main body 321. A pair of lead terminals 322 are exposed in the periphery of the part (see FIG. 8).

  FIG. 6 is a plan view showing the positional relationship between the bus bar 33 and the coil 320 with the power circuit board 31 omitted. Specifically, as shown in FIG. 6, the first bus bar 33A and the second A bus bar are shown. 33B1 is connected with the first coil 320A, the first bus bar 33A and the second B bus bar 33B2 are connected with the second coil 320B, and the connection between the first bus bar 33A and the fourth bus bar 33D is the third coil. The configuration is performed at 320C.

  Here, as described above, the through hole 34 for mounting the electronic component 32 on the bus bar 33 is provided at a position where the electronic component 32 is mounted on the power circuit board 31. As shown in FIG. 5, the coil through hole 34 </ b> A (an example of the connection through hole and the heat radiating through hole) where the coil 320 is mounted among these through holes 34 has a rectangular shape. More specifically, the edge (the upper side and the lower side in FIG. 5) of the main body 321 of the coil 320 on which the lead terminal 322 is located has a long hole and a short width. That is, it is a rectangular shape that is long in the vertical direction in FIG. 5, and the bus bar 33 is exposed from here.

  In addition, another bus bar 33 may be disposed between the bus bars 33 connected to each other. Specifically, as shown in FIG. 6, the third bus bar 33C is disposed between the first bus bar 33A and the second A bus bar 33B1 and between the first bus bar 33A and the second B bus bar 33B2. ing. In other words, the third bus bar 33C is disposed below the main body portions 321 of the first coil 320A and the second coil 320B.

  An insulating heat transfer sheet 37 is disposed between the main body 321 of the coil 320 and the third bus bar 33C facing the main body 321 (see FIG. 8). Further, an insulating heat transfer sheet 39 is also disposed between the main body 321 of the coil 320 and the heat equalizing plate 36 disposed on the upper surface thereof. The main body portion 321 and the third bus bar 33C of the coil 320, and the main body portion 321 and the heat equalizing plate 36 of the coil 320 are in close contact via heat transfer sheets 37 and 39.

(Operation and effect of this embodiment)
According to the present embodiment, instead of the jumper wire that has been conventionally provided for connection between the bus bars 33, the bus bars 33 are connected to each other using the existing coil 320 that is originally necessary. Therefore, the total number of parts can be reduced, and the structure of the circuit structure 30 can be simplified.

  In addition, the third bus bar 33C is disposed between the first bus bar 33A and the second A bus bar 33B1 and between the first bus bar 33A and the second B bus bar 33B2, so that space is wasted. Thus, a high-density circuit structure 30 can be obtained.

  In addition, since the heat generated in the coil 320 can be quickly transferred to the metal third bus bar 33C disposed below the main body portion 321 of the coil 320 to dissipate heat, the circuit component 30 has a high temperature. Can be suppressed. And since the heat-transfer sheet | seat 37 is distribute | arranged between the main-body part 321 and the 3rd bus-bar 33C, it can thermally radiate more efficiently.

  Furthermore, the heat dissipation effect can be further enhanced by the heat sink 40 provided on the lower surface side of the bus bar 33.

  According to such a circuit configuration body 30 of the present embodiment, it is possible to provide a circuit configuration body 30 that can be mounted with high density with a simple configuration.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.

(1) In the above embodiment, a rectangular through hole 34A is provided in a region of the power circuit board 31 corresponding to the main body 321 of the coil 320, and the lead terminal 322 is provided on the bus bar 33 exposed by the through hole 34A. While the heat transfer sheet 37 is arranged and the heat generated from the coil 320 is released to the bus bar 33 while being connected, the connection through hole and the heat dissipation through hole may be separately provided. Alternatively, as a reference example, the heat dissipation through hole may be omitted.

  (2) The heat transfer sheet 37 between the main body 321 of the coil 320 and the third bus bar 33C is not necessarily provided.

  (3) In the above embodiment, the embedded coil 320 that exposes the lead terminal 322 of the coil 320 to the lower surface of the main body 321 is used, but the L-shaped lead terminal 322 is protruded from the lower surface of the main body 321. A coil can also be used.

  (4) The heat sink 40 is not necessarily provided.

  (5) In the above embodiment, an example of a DC-DC converter is shown as the device 10, but the present invention is not limited to this.

DESCRIPTION OF SYMBOLS 10 ... DC-DC converter apparatus 11 ... Case 12 ... Upper case 20 ... Frame 25 ... Under case 30 ... Circuit structure 31 ... Power circuit board (board | substrate)
33 ... Bus bar 33A ... First bus bar 33B1 ... Second A bus bar (second bus bar)
33B2 ... 2B bus bar (2nd bus bar)
33C: Third bus bar 34: Through hole (through hole for connection and through hole for heat dissipation)
35 ... Control circuit board 36 ... Soaking plate 37 ... Heat transfer sheet 40 ... Heat sink (heat sink)
45 ... Shield 320 ... Coil 321 ... Main body 322 ... Lead terminal

Claims (3)

A substrate having a through-hole for connection;
A plurality of bus bars provided on one side of the substrate to constitute a power circuit;
A circuit configuration comprising a main body portion and a pair of lead terminals, and a coil mounted on the other surface side of the substrate by being connected to the bus bar exposed through the connection through hole. Body,
The plurality of bus bars include a first bus bar, a second bus bar, and a third bus bar,
The first bus bar and the second bus bar are connected to each other by the pair of lead terminals of the coil,
The third bus bar is arranged in a region different from the first bus bar and the second bus bar in the region of the substrate corresponding to the main body portion of the coil ,
A circuit structure having a heat dissipation through hole in a region of the substrate corresponding to the main body of the coil . 2. The circuit structure according to claim 1 , wherein a heat transfer sheet is disposed between the main body portion of the coil and the third bus bar exposed by the heat dissipation through hole. The circuit structure according to claim 1 , wherein a heat radiating plate is disposed on a surface of the plurality of bus bars opposite to a surface facing the substrate.

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