JP4579034B2 - Switching unit - Google Patents

Description

  The present invention relates to a switching unit capable of controlling current on / off.

As a conventional switching unit, for example, there is one shown in Patent Document 1. This is, for example, arranged between a power source such as an automobile battery and each electronic device such as a headlamp, and controls each electronic device by switching on / off of a current. In addition, these switching units are provided with connection terminals for connection to the outside, and are used as detachable units for maintenance and the like.
JP 2002-324478 A

  By the way, in recent years, comfort and safety required for automobiles are increasing, and the number of electronic devices installed in automobiles to meet these demands tends to increase. If it does so, there existed a problem that the number of switching units, such as a relay for controlling the increased electronic device, also increased, and the space was required by that much. In addition, in the case of a detachable switching unit, the installation location is restricted, such as the mounting location is exposed to the outside, and it must be installed in a detachable location. It becomes prominent. Due to these problems, there has been a desire to make the switching unit as small as possible.

  The present invention has been completed based on the above situation, and an object thereof is to provide a switching unit that can be miniaturized.

As a means for achieving the above object, the invention of claim 1 is a switching unit comprising a switching device capable of controlling on / off of current and a connection terminal for connection to the outside. A circuit board having a circuit board and a bus bar circuit that are in close contact with each other via the circuit board, and a circuit body in which the switching device is connected to both of them is housed in a casing, and at the end of the bus bar circuit. The connection terminal is integrally extended , and the casing has an opening that exposes a surface on the opposite side of the surface of the bus bar circuit related to the circuit body to which the circuit board is closely attached. Have
The invention of claim 2 is characterized in that, in the invention of claim 1, the surface exposed from the opening of the bus bar circuit is covered with an insulating film.

According to a third aspect of the present invention, in the bus bar circuit according to the first or second aspect, the surface opposite to the surface where the circuit board is in close contact is in close contact with the inner wall of the casing. It has the characteristics.

According to a fourth aspect of the present invention, in the device according to any one of the first to third aspects, the casing and the circuit body are fitted together, and the bus bar circuit is opposite to the surface on which the circuit board is in close contact. This is characterized in that fitting means for restricting the surface of the surface from being separated from the inner wall of the casing is provided.

The invention of claim 5 is characterized in that, in the invention according to any one of claims 1 to 4 , the casing is integrally molded.

<Invention of Claim 1>
Since the circuit board and bus bar circuit are provided inside the switching unit, a complicated circuit that would increase in size when formed with the bus bar circuit is formed with the circuit board, and the input / output circuit and the connection terminal are connected to the bus bar circuit. Therefore, the switching unit can be reduced in size.
Further, since the bus bar is exposed to the outside through the opening, the heat dissipation can be improved.

<Invention of Claim 3 >
By closely contacting the bus bar with the circuit board in the circuit body, the bus bar can easily absorb the heat generated on the circuit board side, that is, the bus bar can be used as a heat dissipation means. In addition, since the bus bar is brought into close contact with the inner wall of the casing, the heat of the bus bar can be easily transmitted to the inner wall of the casing and can be easily released to the outside through the casing, so that the heat dissipation can be improved.

<Invention of Claim 4 >
Since the casing and the circuit body are fitted by the fitting means and the bus bar is restricted from being separated from the casing, the adhesion between the bus bar and the casing is increased, and heat transfer between them can be smoothly performed. Further improvement is possible.

<Invention of Claim 5 >
Since the casing is molded integrally, the number of parts can be reduced and the manufacturing process can be shortened, and the manufacturing efficiency can be improved.

<Embodiment 1>
A first embodiment of the present invention will be described with reference to FIGS.
As shown in FIGS. 1 and 2, the switching unit 10 has a unit main body (corresponding to a “circuit body” of the present invention) 15 surrounded by a casing 20, and extends from the unit main body 15 to the outside of the casing 20. The connecting terminal 12A to be connected to the counterpart connection terminal (not shown) is detachably attached to an electrical connection box (not shown) or the like.

The unit main body 15 includes a circuit board 11, a bus bar circuit 12, and a switching device 13 (see FIG. 2).
The switching device 13 is capable of controlling on / off of current, and in this embodiment, a semiconductor switching element is used. In particular, in this embodiment, a power MOSFET portion and an overheat protection function or A control unit having a PWM signal transmission unit and the like arranged on one chip is used.

  As shown in FIG. 1, the circuit board 11 includes a printed circuit in which a conductive path is formed on a substantially rectangular insulating substrate by screen printing or the like, and a through hole 11 </ b> A is formed at a predetermined position. The electronic device mounted on the surface of the switching device 13 or other resistor or other circuit board 11 is connected directly to the bus bar circuit 12 described below through this through hole 11A (see FIG. 2). ). In this embodiment, the switching device 13 is mounted on one side (the right side in FIG. 1) of the circuit board 11, and a control system circuit is arranged on the opposite side (the left side in FIG. 1) (not shown in detail). Has been established.

The bus bar circuit 12 is formed in a predetermined circuit shape by a plurality of bus bars formed by punching a metal flat plate (see a broken line in FIG. 1). The bus bar circuit 12 has a substantially rectangular shape similar to that of the circuit board, and the strength of the unit main body 15 can be secured by supporting the entire area of the circuit board 11 with the bus bar circuit 12. Yes.
Further, the bus bar constituting the bus bar circuit 12 is integrally formed with a connection terminal 12A extending from the unit body 15, and the connection terminal 12A is fitted to a mating connection terminal such as an electric connection box (not shown). It is possible. In the present embodiment, as shown in FIG. 1, five connection terminals 12A are provided. Of these, the left three in FIG. 1 are used as control system terminals, and the right two terminals are power systems. Used as a terminal. Moreover, the front-end | tip part of the control system terminal (three terminals on the left side of FIG. 1) is formed thinner than the power system terminals (two terminals on the right side of FIG. 1) by press working.

Now, the switching unit 10 of the present embodiment is configured such that the bus bar circuit 12 is in close contact with the lower surface side of the circuit board 11 in the unit body 15. Here, between the circuit board 11 and the bus bar circuit 12, an adhesive (for example, a silicone-based adhesive or an epoxy-based adhesive) or an adhesive sheet (for example, an adhesive is applied to both surfaces of an insulating sheet to provide adhesion) ) And are insulated and intimately adhered, and these adhesives or adhesive sheets correspond to the “insulator” of the present invention.
Further, the unit body 10 is formed by mounting the switching device 13 on the surface on the circuit board 11 side, although the circuit board 11 and the bus bar circuit 12 are in close contact (see FIG. 2).

The casing 20 has a substantially rectangular parallelepiped shape as a whole, and can accommodate the upper main body 21, the lower receiving body 22, and the unit main body 15.
The receiving body 22 is formed with a groove 22A at a position where the connection terminal 12A is led out, and the connection terminal 12A can be led out from the casing 20 without a gap by fitting the connection terminal 12A into the groove 22A (see FIG. 3).
Further, the receiving body 22 of the casing 20 is formed with an opening 20 </ b> A on the surface of the unit body 15 corresponding to the bus bar circuit 12 (the lower side in FIG. 2). The heat dissipation is enhanced by exposing the lower surface of the bus bar circuit 12 to the outside through the opening 20A.
In the present embodiment, the surface exposed to the outside from the opening 20 </ b> A of the bus bar circuit 12 is covered with the insulating film 25. The insulating coating 25 is formed by adhering a thin insulating sheet to the bus bar circuit 12. By insulating the bus bar, a short circuit with the outside such as an electrical junction box can be regulated.

The switching unit 10 configured as described above is detachably assembled to an electrical connection box (not shown), receives a predetermined electrical signal from the control system terminal, and operates the switching device 13 to thereby operate the power system terminal. The current input from the input side is adjusted as appropriate and output from the output side of the power system terminal to operate the electronic device (not shown).
Here, when the switching device 13 mounted on the upper side of the circuit board 11 or another electronic element such as a resistor operates to generate heat, or when heat is generated by current flowing through the conductive path of the circuit board 11, the heat conductive A high bus bar circuit 12 absorbs these heats. The lower surface side of the bus bar circuit 12 is exposed to the outside through the opening 20A of the casing 20, and heat can be released from this portion to the outside. .
Note that the switching unit 10 can be removed during maintenance of an electrical connection box (not shown) or the like, and can be replaced and used as necessary.

  Thus, according to the switching unit 10 of the present embodiment, the circuit board 11 and the bus bar circuit 12 are provided inside the switching unit 10. As a result, in addition to forming a complicated circuit such as a control system circuit that would increase in size when formed with the bus bar circuit 12, the circuit for performing input / output and the connection terminal 12A are connected to the bus bar circuit 12. It is formed integrally with one bus bar member. Therefore, the switching unit 10 can be downsized.

  Further, in the present embodiment, the circuit board 11 and the bus bar circuit 12 are in close contact with each other, and one terminal of the switching device 13 is directly connected to the bus bar circuit 12. Thereby, the heat generated on the switching device 13 and the circuit board 11 is absorbed by the bus bar circuit 12 made of a metal plate having good thermal conductivity, and further, the bus bar circuit 12 is exposed to the outside from the opening 20A of the casing. Excellent heat dissipation.

  Further, in the unit main body 15 of the present embodiment, the bus bar circuit 12 is affixed over almost the entire surface of the circuit board 12, so that sufficient strength can be ensured even in the state of the unit main body 15 before being assembled to the casing 20 alone. it can.

  In the present embodiment, since a semiconductor switching element is used for the switching device 13, no operation noise is generated in the so-called mechanical relay when the contact is turned on / off.

< Reference Example 1 >
Next, Reference Example 1 will be described with reference to FIG.
The switching unit 10A of Reference Example 1 is different from the first embodiment in that the casing 20 is integrally formed by molding, but other similar configurations are denoted by the same reference numerals and are duplicated. Description is omitted.
In Reference Example 1 , the main body 21 and the receiver 22 of the casing 20 in the first embodiment are integrally formed by molding. Further, the insulating film 25 according to the first embodiment is omitted by forming a thin film body integrally with the casing 20 on the lower surface of the bus bar circuit 12 at the location where the insulating film 25 in the first embodiment is provided. is doing.
Note that, in Reference Example 1 , the heat dissipation of the casing 20 as a whole is improved by using a resin in which a filler such as alumina is added to the resin constituting the casing 20.

As described above, the switching unit 10A of Reference Example 1 can reduce the number of parts by integrally molding a portion corresponding to the casing 20 and the insulating coating 25 of the first embodiment by molding with resin, and accordingly. Since the assembly process can be reduced, the production efficiency can be improved.

< Reference Example 2 >
Next, Reference Example 2 will be described with reference to FIGS.
In the switching unit 10B of Reference Example 2 , the configuration of the casing 20 is different from that of the first embodiment, but other similar configurations are denoted by the same reference numerals, and redundant description is omitted.
The casing 20 of Reference Example 2 has a wall surface except where the main body 21 attaches the lid body 22F, and the entire surface of the main body 21 on the side from which the connection terminal 12A is led out (left side in FIG. 6) is covered with the lid body 22F. It is supposed to block.
The lid body 22F is provided with insertion holes 24 at positions where the connection terminals 12A are disposed so that the connection terminals 12A can be led out of the casing 20 (see FIGS. 8 and 10). The insertion hole 24 is formed in substantially the same shape as the outer shape of the connection terminal 12A so that the connection terminal 12A can be inserted without a gap (see FIG. 7).
A groove 23 is formed on the inner wall of the main body 21 so as to correspond to the peripheral edge of the circuit board 11 as shown in FIGS. When the circuit board 11 is fitted, the groove 23 restricts the vertical movement of the unit main body 15 and restricts the lower surface of the bus bar circuit 12 of the unit main body from being separated from the inner wall surface of the main body 21. .
When the unit main body 15 is assembled to the casing 20, the unit main body 15 can be easily positioned by inserting the circuit board 11 into the groove 23 and sliding it (see FIG. 8). As a result, the assembling work is performed smoothly.
After the unit main body 15 is inserted into the main body 21, the casing 20 can be closed by surrounding the entire circumference of the unit main body 15 by assembling the lid 22 </ b> F. Thereby, dustproofness and waterproofing can be improved.
As described above, according to the switching unit 10B of the reference example 2 , it is possible to improve the assembling property and to improve the dustproof property and the waterproof property.

<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, and further, within the scope not departing from the gist of the invention other than the following. Various modifications can be made .

( 1 ) In the above embodiment, the switching unit 10 is a device in which a semiconductor switching element is mounted on the switching device 13. However, the present invention is not limited to this. For example, an IC or the like may be mounted. Moreover, in the said embodiment, although the switching device 13 used what arrange | positioned the power MOSFET part and the control part which has an overheat protection function or a PWM signal transmission part etc. in the one-chip in the semiconductor device. For example, it may be configured only by a power MOSFET unit that does not include a control unit.
( 2 ) In the above embodiment, an IC, a microcomputer or the like may be mounted on the control system circuit .
( 3 ) In the said embodiment, although the semiconductor switching element was mounted in the switching device 13, it is not restricted to this, For example, you may mount a bare chip.

Plan sectional view of the switching unit of Embodiment 1 Longitudinal sectional view at X-X 'of the switching unit A plan view from the connection terminal lead-out direction of the switching unit Vertical section of the switching unit of Reference Example 1 Plan sectional view of the switching unit of Reference Example 2 Longitudinal sectional view of the switching unit at Y-Y ' A plan view from the connection terminal lead-out direction of the switching unit Exploded sectional view of switching unit Plan view viewed from the opening side of the casing body Exploded sectional view of the switching unit on the side facing the lid body

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Switching unit 11 ... Circuit board 12 ... Bus-bar circuit 12A ... Connection terminal 13 ... Switching device 15 ... Unit main body (circuit body)
20 ... Casing 20A ... Opening

Claims (5)

In a switching unit comprising a switching device capable of controlling on / off of current and a connection terminal for connection to the outside,
A circuit board and a bus bar circuit that are in close contact with each other via an insulator, and a circuit body in which the switching device is connected to both of them are housed in a casing, and provided.
The connection terminal is integrally extended at an end of the bus bar circuit ,
The switching unit according to claim 1, wherein the casing has an opening that exposes a surface opposite to a surface of the bus bar circuit of the circuit body opposite to a surface to which the circuit board is closely attached . The switching unit according to claim 1 , wherein a surface exposed from the opening of the bus bar circuit is covered with an insulating film. 3. The switching unit according to claim 1, wherein a surface of the bus bar circuit opposite to a surface to which the circuit board is in close contact is in close contact with an inner wall of the casing. The casing and the circuit body are fitted to each other, and a fitting means is provided for restricting the surface of the bus bar circuit opposite to the surface to which the circuit board is closely attached from the inner wall of the casing. The switching unit according to any one of claims 1 to 3, wherein The switching unit according to any one of claims 1 to 4 , wherein the casing is integrally molded.

Images