JP2006311711A - Switching unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a switching unit that can reduce the size and improve the heat radiation properties. <P>SOLUTION: The switching unit 10 is surrounded by a casing 20 and has a unit body 15 and a connection terminal 12A. In the unit body 15, a switching device 13 is packaged onto a surface at the side of a circuit board 11, where the circuit board 11 adheres to a bus bar circuit 12. The connection terminal 12A is extended to the outside the casing 20 from the unit body 15. Additionally, a bus bar 12T for constituting the bus bar circuit 12 is made thick for improving heat transfer properties in the bus bar circuit 12. As a result, in the switching unit 10, a complex circuit is formed by the circuit board 11, and a circuit for performing input and output and the connection terminal 12A are formed integrally by the bus bar circuit 11 for miniaturization. Heat generated in the unit body 15 is discharged to the outside via the bus bar circuit 12, whose heat transfer properties are improved, thus enabling increase in the heat radiation properties. <P>COPYRIGHT: (C)2007,JPO&INPIT

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.
In addition, as the number of electronic devices installed in automobiles increases, the amount of power consumed by the entire vehicle increases, and if it is simply downsized, the heat generation density increases and heat accumulates, which may adversely affect electronic devices. there were.

  The present invention has been completed based on the above-described circumstances, and an object thereof is to provide a switching unit that can be reduced in size and improved in heat dissipation.

  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 a casing, and a circuit body in which the switching device is connected to both of them is housed in a casing, and the bus bar circuit has a thick bus bar. And the connection terminal is integrally extended at the end of the bus bar circuit.

  According to a second aspect of the present invention, the bus bar circuit according to the first aspect is characterized in that a surface opposite to a surface to which the circuit board is in close contact is in close contact with the inner wall of the casing. .

  The invention of claim 3 is characterized in that, in the invention of claim 1 or 2, the casing is provided with a fitting chamber into which the bus bar can be fitted.

  The invention of claim 4 is characterized in that, in the invention according to any one of claims 1 to 3, the casing has a partition wall interposed between bus bars constituting a bus bar circuit.

<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.
Furthermore, since the bus bar circuit is formed of a thick bus bar, the heat generated in the circuit body can be absorbed and diffused easily, and the heat dissipation can be improved.

<Invention of Claim 2>
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 3>
By fitting the bus bar into the fitting chamber of the casing, the bus bar can be easily positioned and the bus bar circuit can be securely held.

<Invention of Claim 4>
Since the partition wall is provided between the adjacent bus bars, the insulation between the bus bars can be reliably performed even if the bus bars are thick.

<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 is formed by mounting the switching device 13 on the surface of the circuit board 11 side in which the circuit board 11 and the bus bar circuit 12 are in close contact (see FIG. 2). 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.
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 in the present embodiment is formed in a predetermined circuit shape by a plurality of bus bars 12T formed by appropriately punching and pressing a metal flat plate (see FIG. 5). As shown in FIG. 2, each bus bar 12T constituting the bus bar circuit 12 is formed of a thick plate material. Here, the thickness of the bus bar 12T is set to be larger than the thickness determined in consideration of the current capacity of the bus bar circuit 12, and the thickness is such that the heat generated in the unit body 15 can be easily absorbed. By being set, the thermal conductivity of the entire bus bar circuit 12 is increased.
Further, the bus bar circuit 12 has a substantially rectangular shape similar to that of the circuit board 11, and the bus bar circuit 12 supports an area covering almost the entire circuit board 11, so that the unit main body 15 and thus the entire switching unit 10 can be fully supported. Strength can be secured.

  Further, the bus bar circuit 12 is provided with connecting projections 12C at locations corresponding to the through holes 11A of the circuit board 11 described above. The connection convex portion 12C is provided on the surface of the bus bar 12T so as to project toward the circuit board 11, and the connection convex portion 12C is accommodated in the through hole 11A, so that the connection portion with the bus bar circuit 12 and the circuit board 11 is substantially flush (see FIGS. 2 and 4), so that the switching device 13 and each electronic element of the unit body 15 can be easily mounted.

  Further, the bus bar 12T 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). 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.

The casing 20 has a substantially rectangular parallelepiped shape as a whole, and can accommodate the unit main body 15 by an upper main body 21 and a lower receiving body 22 (see FIG. 2).
The receiving body 22 is formed with a fitting chamber 22C. The insertion chamber 22 </ b> C has a peripheral wall 22 </ b> B arranged in accordance with the shape of each bus bar 12 </ b> T forming the bus bar circuit 12. By inserting each bus bar 12T into a corresponding position, it is possible to position each bus bar 12T, and by interposing the peripheral wall 22B of the insertion chamber 22C between each bus bar 12T, insulation between the bus bars 12T is achieved. It is like that. The height of the peripheral wall 22B interposed between the bus bars 12T is set so as not to contact the surface of the circuit board 11 on the bus bar circuit 12 side in the unit main body 15 so as not to interfere with the circuit board 11. It has become.
Further, the surface opposite to the mounting surface of each bus bar 12T fitted in the insertion chamber 22C (the lower surface in FIG. 2) is in close contact with the bottom wall of the receiving body 22, and this bottom wall is formed on the casing 20. It is formed thinner than other wall surfaces. For this reason, the heat absorbed by the bus bar circuit 12 is easily released to the outside.
Furthermore, a groove 22A is formed in the receiving body 22 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 any gap by fitting the connection terminal 12A into the groove 22A. (See FIG. 3).

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. Then, heat can be released to the outside through the casing 20 to which the bus bar circuit 12 is in close contact.
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 bus bar circuit 12 configured with the thick bus bar 12T and having high thermal conductivity is brought into close contact with the circuit board 11, and one terminal of the switching device 13 is directly connected to the bus bar circuit 12. It has become. As a result, heat generated on the switching device 13 and the circuit board 11 is absorbed and diffused by the bus bar circuit 12 having good thermal conductivity and discharged to the outside through the casing 20, so that heat dissipation is excellent.

  Further, in the switching unit 10 of the present embodiment, the bus bar 12T is brought into close contact with the bottom wall of the receiver 22 of the casing 20 in the unit main body 15, so that the heat of the bus bar circuit 12 can be easily transferred to the inner wall of the casing 20. Since it becomes easy to discharge to the outside, the heat dissipation can be improved.

Further, by fitting the bus bar 12T into the insertion chamber 22C of the casing 20, the bus bar 12T can be easily positioned and the bus bar circuit 12 can be reliably held.
Furthermore, since the peripheral wall 22B is provided between the adjacent bus bars 12T, the insulation between the bus bars 12T can be reliably performed even if the bus bars 12T are thick.

  Further, in the unit main body 15 of the present embodiment, the bus bar circuit 12 made of a thick metal plate is affixed over almost the entire surface of the circuit board 12, so that the unit main body 15 before being assembled to the casing 20. Sufficient strength can be secured even in the state of only.

  In the present embodiment, since a semiconductor switching element is used for the switching device 13, operation noise generated when the contact is turned on / off is not generated in a so-called mechanical relay.

<Embodiment 2>
Next, a second embodiment of the present invention will be described with reference to FIGS.
The switching unit 10A of the present embodiment is different from that of the first embodiment in that the connection terminal 12A includes the branch terminal 12B. However, other similar configurations are denoted by the same reference numerals, and redundant description is given. Is omitted.
In the present embodiment, the outer peripheral edge of the circuit board 11 is inserted into the groove 23 formed on the inner wall surface of the main body 21 of the casing 20 (see FIG. 9). And when the unit main body 15 is accommodated in the casing 20, it will assemble | attach so that the lower surface of the bus-bar circuit 12 may closely_contact | adhere to the inner wall of the casing 20 (refer FIG. 9). Thereby, when the heat generated in the unit main body 15 is absorbed by the bus bar, the heat is easily released because the heat is easily released to the outside through the casing 20.
Further, the two terminals on the right side in FIG. 8 constitute branch terminals 12B and 12B that branch off from one branch bus bar 12J and extend.
The branch bus bar 12J is one of the bus bars constituting the bus bar circuit 12. The branch bus bar 12J has one path on the inner side (unit main body 14 side) and a plurality of paths on the outer side (two paths in this embodiment). It branches and forms the branch terminal 12B in each front-end | tip. The switching unit 10 </ b> A of the present embodiment includes such a branch terminal 12 </ b> B, so that in the unit body 15, a circuit connected to one path can be connected to two different paths connected to each of the branch terminals 12 </ b> B. This increases the degree of freedom in circuit design.

<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) Although the switching unit is housed in the box-shaped casing 20 in the above embodiment, the present invention is not limited to this. For example, the switching unit may include a casing integrally formed by molding. According to such a configuration, since the number of parts can be reduced and the manufacturing process can be shortened, the manufacturing efficiency is further improved.
(2) In the said embodiment, the heat dissipation of the casing 20 whole may be improved by using resin which added fillers, such as an alumina, to resin which comprises a casing.
(3) In the above embodiment, the bus bar circuit 12 is housed inside the casing. However, the present invention is not limited to this, and the surface opposite to the mounting surface of the bus bar circuit is exposed to the outside of the casing 20. There may be. Further, in this case, it is desirable that the exposed surface of the bus bar circuit 12 is covered with an insulating film to restrict a short circuit between the outside and the bus bar circuit 12.
(4) In the above embodiment, the switching units 10 and 10A mount the semiconductor switching element on the switching device 13. However, the present invention is not limited to this. For example, an IC or the like may be mounted.
(5) In the above embodiment, an IC, a microcomputer or the like may be mounted on the control system circuit.
(6) In the said embodiment, the thing of the structure which adds heat radiating means, such as a heat sink and a heat fin, may be sufficient.
(7) Although the semiconductor switching element is used for the switching device 13 in the above embodiment, the present invention is not limited thereto, and a bare chip or the like may be mounted.
(8) In the above embodiment, the casing 20 is made of resin, but may be made of metal, for example. In this case, for example, it is desirable that the insulation between the casing and the unit body is achieved by forming an insulating film on the surface of the metal casing.

Plan sectional view of the switching unit of Embodiment 1 X-X 'longitudinal sectional view of the switching unit Plan view of the switching unit viewed from the connection terminal lead-out direction Exploded sectional view of switching unit Cross section of busbar circuit Plan view of casing receiving part Y-Y 'longitudinal section Plan sectional drawing of the switching unit of Embodiment 2. Longitudinal sectional view of the switching unit at Z-Z ′ Plan view of the switching unit viewed from the connection terminal lead-out direction

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Switching unit 11 ... Circuit board 12 ... Bus bar circuit 12A ... Connection terminal 12T ... Bus bar 13 ... Switching device 15 ... Unit main body (circuit body)
20 ... casing 22B ... peripheral wall (partition wall)
22C ... Insertion room

Claims (4)

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 having 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 is provided in a casing,
A switching unit, wherein the bus bar circuit is formed of a thick bus bar, and the connection terminal is integrally extended at an end of the bus bar circuit. 2. The switching unit according to claim 1, wherein the bus bar circuit has a surface opposite to a surface to which the circuit board is in close contact with an inner wall of the casing. The switching unit according to claim 1, wherein the casing includes a fitting chamber into which the bus bar can be fitted. The switching unit according to any one of claims 1 to 3, wherein the casing has a partition wall interposed between bus bars constituting a bus bar circuit.

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