JP2000272443A - Power distribution device for vehicles - Google Patents

Abstract

(57) [Problem] To provide a small power distribution device excellent in heat dissipation. A power distribution device for a vehicle for distributing electric power supplied from a power supply to a plurality of electric loads, the bus bar having a plurality of branch portions connected to a power supply line from the power supply.
A switching element 2 attached to the branch 12 of the bus bar 1 to supply and cut off power to a plurality of electric loads; a base 11 of the bus bar 1 and the branch 12 of the bus bar 1 to which the switching element 2 is attached. And a fuse 5 whose main body 51 is formed of a high thermal conductive resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power distribution device mounted on a vehicle, and more particularly to a small power distribution device excellent in heat dissipation.

[0002]

2. Description of the Related Art A vehicle power distribution device of this type is mounted on a vehicle to supply electric power from a battery or a generator to a plurality of on-vehicle electrical components. MOSFETs and fuses are connected by bus bars, and these are provided in the box.

FIG. 5 is a perspective view showing an example of the inside of a box body. A power supply line 8 is connected to one end of a bus bar 1 mounted on a substrate 3. The bus bar 1 extending from the power supply line 8 is branched into a plurality of bus bars 1, and a fuse 5 for preventing an overcurrent and a semiconductor switch 2
Is attached, and a connector (not shown) is provided at the end of the connector, to which a harness to the on-vehicle electrical components is connected. Such a power distribution device is mounted, for example, at the feet of a driver's seat or a passenger seat in a room.

[0004]

However, in the conventional power distribution device for a vehicle, the semiconductor switch 2 and the fuse 5 as heating elements are separately installed in one box body, and these are connected by the bus bar 1. Due to the structure, there is a problem that the heat radiating plate 9 becomes large and the power distribution device itself becomes large.

In addition, due to the layout in the box, the structure of the heat radiating plate 9 becomes complicated, or a cooling fan 10 is required separately because sufficient heat radiation cannot be exhibited. However, there were also problems such as cost increase and weight increase.

Further, the contact resistance between the fuse 5 and the terminal between the power supply line 8 and the bus bar 1 is large.
There was also a risk of burning.

SUMMARY OF THE INVENTION The present invention has been made in view of such problems of the prior art, and has as its object to provide a small power distribution device for a vehicle having excellent heat dissipation.

[0008]

According to a first aspect of the present invention, there is provided a vehicle power distribution device for distributing electric power supplied from a power supply to a plurality of electric loads. A bus bar to which a power supply line from the power supply is connected, the bus bar having a plurality of branch portions, a switching element attached to the branch portion of the bus bar, for supplying and interrupting power to the plurality of electric loads, and a base portion of the bus bar; The switching element is interposed between a branch portion of the bus bar to which the switching element is attached, and a main body portion of the bus bar includes a fuse formed of a high thermal conductive resin.

In this case, although not particularly limited, claim 2
As in the vehicle power distribution device described above, it is preferable that a heat radiator is provided on the bus bar.

In the power distribution device for a vehicle according to the present invention, the switching element, which is a heating element, is attached to the branch portion of the bus bar, and a fuse made of a high thermal conductive resin is interposed between the base portion and the branch portion of the bus bar. Therefore, the heat generated in the switching element is transmitted to the base of the bus bar via the fuse, and is radiated from the radiator provided here.
Therefore, sufficient heat radiation can be obtained without providing a heat radiator for each switching element, and a cooling fan can be omitted or the capacity can be reduced.

Although not particularly limited in the above invention,
In the power distribution device for a vehicle according to claim 3, a board provided with the bus bar, an electronic component for performing ON / OFF control of the switching element, and a wiring pattern for connecting the switching element and the electric load are provided. It is further characterized by being provided.

In this case, although not particularly limited, claim 4
As in the vehicle power distribution device described above, it is preferable that the substrate is formed of a high heat conductive resin.

Since the board on which the components of the power distribution device are mounted is made of a highly thermally conductive resin, the heat generated by the switching element can be radiated also through the board, and the heat dissipation is further improved. Omission of the cooling fan or reduction in the capacity can be expected.

Although not particularly limited in the above invention,
In the power distribution device for a vehicle according to claim 5, the fuse has a main body formed of a high thermal conductive resin, and a current interrupting portion formed of a metal conductor, and both ends of the current interrupting portion are the opposite ends. The fuse is mounted on the bus bar by being provided so as to protrude from the main body, and fitting the convex portion of the current interrupting portion into a concave portion formed at each of the base portion and the branch portion of the bus bar. I do.

A fuse for preventing an overcurrent is constituted by a main body made of a high thermal conductive resin and a current interrupting portion for interrupting a current, and is formed between a base portion and a branch portion of the bus bar. The concave / convex fitting (or insertion / removal insertion) into the recessed portion improves the operability of attaching and detaching the fuse, and increases the contact area between the current interrupting section and the bus bar, thereby reducing contact resistance and suppressing heat generation at the contact portion. can do.

Although not particularly limited in the above invention, in the power distribution device for a vehicle according to the present invention, a gas layer is provided in a closed space formed in the main body between both ends of the current interrupting portion of the fuse. It is characterized by being provided through.

By changing the cross-sectional area between both ends of the current interrupting portion for interrupting the overcurrent, the current interrupting characteristic, that is, the threshold value of the interrupting current can be changed. Further, the threshold value of the cutoff current can be changed by providing the both ends of such a current cutoff unit via a gas layer and changing the type of gas sealed in the gas layer.

Although not particularly limited, the fuse according to the present invention preferably has a groove for engaging with a holding claw provided on the substrate, as described in claim 7, and as described in claim 8, Preferably, it is formed symmetrically with respect to the mounting direction to the bus bar.

When the fuse is attached to or detached from the bus bar, by employing an engagement structure between the holding claw and the groove, the attachment / detachment operation can be performed with one touch, thereby improving workability. Further, by forming the fuses symmetrically, there is no directivity when the fuses are mounted on the bus bar, which also improves workability.

[0020]

According to the first and second aspects of the present invention,
The heat generated by the switching elements is transmitted to the base of the bus bar via the fuse and is radiated from the radiator provided here, so that sufficient heat radiation can be obtained without providing a radiator for each switching element. The cooling fan can be omitted or the capacity can be reduced.

In addition, according to the third and fourth aspects of the present invention, the heat generated by the switching element can be radiated through the substrate, so that the heat radiation is further improved and the cooling fan is omitted. Alternatively, a further reduction in capacity can be expected.

According to the fifth aspect of the present invention, the operability of attaching and detaching the fuse is improved, and the contact area between the current interrupting portion and the bus bar is increased, so that the contact resistance is reduced and the heat generation at the contact portion is suppressed. can do.

According to the sixth aspect of the present invention, the current interrupting characteristics can be easily changed by changing the cross-sectional area of the current interrupting portion or the gas sealed in the gas layer.

According to the seventh and eighth aspects of the present invention, the attachment / detachment of the fuse is a one-touch operation, and the direction at the time of attachment is lost, so that the workability is remarkably improved.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a main part of an embodiment of a vehicle power distribution device of the present invention, FIG. 2 is a perspective view showing a fuse of FIG. 1, FIG. 3 is a sectional view taken along line III-III of FIG. FIG. 4 is a sectional view taken along the line IV-IV in FIG.

In the power distribution device of this embodiment, a bus bar 1, a switching element 2, a fuse 5, a microcomputer chip 6 (corresponding to an electronic component of the present invention) and a wiring pattern are mounted on a substrate 3 shown in FIG. This is stored in a box (not shown).

The bus bar 1 made of a metal conductor has a base 11 formed in a block shape and extending in one direction of the substrate 3, and a plurality of branch portions 12 formed integrally with the base 11. Although only two branch portions 12 are shown in FIG. 1, actually, the branch portions 12 are provided in a number corresponding to the number of vehicle-mounted electrical components to which power is to be distributed.

A semiconductor switch 2 such as a power MOSFET (hereinafter simply referred to as a switching element) is mounted at the tip of each branch 12 of the bus bar 1 such that a power input terminal thereof contacts the branch 12. I have. In this example, three switching elements 2 are mounted on each branching unit 12. The command signal from the microcomputer chip 6 is input to the command signal input terminal of the switching element 2 via the wiring pattern 4, while the distributed power is supplied from the output terminal of the switching element 2 to the wiring pattern 4. To a connector (not shown) through which the connector of the on-vehicle electrical component is connected.

The wiring pattern 4 for connecting the switching element 2 to the microcomputer chip 6 and the wiring pattern 4 for connecting the switching element 2 to a connector (not shown) may be printed directly on the substrate 3 or may be thin. It may be configured by mounting a conductor on the substrate 3. The substrate 3 is
It is desirable to be made of an insulating resin such as nylon having excellent heat conductivity and hygroscopicity.

In the present embodiment, the base 1 of the bus bar 1
A heat sink 9 is attached to the back surface of 1, and heat generated in the switching element 2 is mainly radiated from here.

The branch 12 of the bus bar 1 is partially cut off in the middle, and the fuse 5 is inserted here. As shown in FIG. 2, the fuse 5 according to the present embodiment has a main body 51 made of an insulating resin having a substantially rectangular parallelepiped shape.
And a current interrupting section 52 made of a metal conductor provided on the main body section 51.

As shown in FIGS. 3 and 4, the current interrupting portion 52 has a convex portion 52 projecting from the main body portion 51 to one side.
1 and a cylindrical portion 522 formed between these convex portions 521 and 521, and the cylindrical portion 522 mainly serves as a cut portion for preventing overcurrent. Also, this cylindrical portion 522
A gas layer 54 is formed in a closed space formed in the main body 51 and around it. By changing the type of gas sealed in the gas layer 54, the cylindrical portion 522 made of metal conductor is formed.
, Ie, the cut-off threshold, changes. For example, when helium gas or argon gas is sealed in the gas layer 54, the cutoff threshold becomes higher than when air is sealed. Further, not only the type of gas in the gas layer 54 but also the cross-sectional area of the cylindrical portion 522 of the current cut-off portion 52 can be changed to change the cut-off characteristics. For example, when the cross-sectional area of the cylindrical portion 522 is increased, the cutoff threshold value increases.

The projections 521, 52 of the current interrupting section 52
Reference numeral 1 denotes a shape that fits into the concave portions 13 formed between the base portion 11 and the branch portion 12 of the bus bar 1. That is, when the fuse 5 is mounted on the bus bar 1, the protrusions 521 and 521 of the fuse 5 are
It can be attached with one touch by inserting it into 3,13. In this case, as shown in FIG. 1, the holding claws 7 are provided on the substrate 3 side, the grooves 53 are formed in the main body portion 51 of the fuse 5, and these are fitted to each other so that the fuse 5 is mounted on the substrate 3.
Fixed to.

The fuse 5 of this embodiment has a symmetrical shape with respect to the insertion direction, and the grooves 53 of the main body 51 are also formed at symmetrical positions. Thus, when the fuse 5 is mounted, the direction in which the fuse 5 is mounted is lost, so that the mounting workability is remarkably improved, and the effect is particularly large in a small space in the vehicle interior where the power distribution device of the present embodiment is provided.

According to the power distribution device of the present embodiment configured as described above, the switching element 2 operates according to the command signal from the microcomputer chip 6, and the switching element 2 generates heat at this time. The heat reaches the base 11 of the bus bar 1 via the main body 51 of the fuse 5 and is radiated to the surroundings from the heat sink 9 mounted thereon. In particular, since the main body 51 of the fuse 5 is made of a high thermal conductive resin, the switching element 2 → the bus bar branch 12 →
The heat flow from the main body 51 of the fuse 5 → the bus bar base 11 → the heat sink 9 becomes smooth.

Further, since the bus bar 1 is formed in a block shape, a plurality of branch portions 12 are provided, and the switching element 2 is mounted thereon, the structure of the heat sink 9 is simplified and heat is concentrated. In addition, the diffusion becomes efficient, and the cooling fan can be omitted or its capacity can be reduced. Thus, not only the cost can be reduced but also the power distribution device itself can be downsized.

The embodiments described above are described for facilitating the understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part showing an embodiment of a vehicle power distribution device of the present invention.

FIG. 2 is a perspective view showing the fuse of FIG. 1;

FIG. 3 is a sectional view taken along the line III-III in FIG. 2;

FIG. 4 is a sectional view taken along the line IV-IV in FIG. 2;

FIG. 5 is a perspective view showing a main part of a conventional vehicle power distribution device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Bus bar 11 ... Base 12 ... Branch part 13 ... Concave part 2 ... Switching element 3 ... Substrate 4 ... Wiring pattern 5 ... Fuse 51 ... Body part 52 ... Current interruption part 521 ... Protrusion part (both ends) 522 ... Cylinder part (between both ends) 53 ... groove 54 ... gas layer 6 ... microcomputer chip (electronic component) 7 ... holding claw 8 ... power supply line 9 ... heat sink (radiator)

Claims (8)

[Claims] 1. A vehicle power distribution device for distributing electric power supplied from a power supply to a plurality of electric loads, comprising: a bus bar connected to a power supply line from the power supply and having a plurality of branch portions; A switching element that is attached and supplies and shuts off power to the plurality of electric loads, and is interposed between a base part of the bus bar and a branch part of the bus bar to which the switching element is attached, and a main body part thereof is provided. A power distribution device for a vehicle, comprising: a fuse formed of a high thermal conductive resin. 2. The power distribution device for a vehicle according to claim 1, wherein a heat radiator is provided on the bus bar. 3. A board provided with the bus bar, an electronic component for performing ON / OFF control of the switching element, and a wiring pattern for connecting the switching element and the electric load. The power distribution device for a vehicle according to claim 1 or 2, wherein 4. The power distribution device for a vehicle according to claim 3, wherein said substrate is formed of a high thermal conductive resin. 5. The fuse has a main body formed of a high thermal conductive resin and a current interrupting section formed of a metal conductor, and both ends of the current interrupting section are provided to protrude from the main body. 5. The fuse according to claim 1, wherein the fuse is mounted on the bus bar by fitting a convex portion of the current interrupting portion into a concave portion formed at each of a base portion and a branch portion of the bus bar. The vehicle power distribution device according to any one of the above. 6. The power distribution device for a vehicle according to claim 5, wherein a portion between both ends of the current interrupting portion of the fuse is provided in a closed space formed in the main body via a gas layer. . 7. The fuse according to claim 3, wherein said fuse has a groove for engaging with a holding claw provided on said substrate.
7. The power distribution device for a vehicle according to any one of 6. 8. The power distribution device for a vehicle according to claim 7, wherein the fuse is formed symmetrically with respect to a mounting direction to the bus bar.