JP2006310558A - Switching unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a switching unit for realizing reduction in size and improving waterproofing property. <P>SOLUTION: The switching unit 10 comprises a unit body 15 which is surrounded by a casing 20 and mounts a switching device 13 to the front surface in the side of a circuit board 11 where a circuit board 11 and a bus bar circuit 12 are provided closely with each other, and a connecting terminal 12A extended to the external side of the casing 20 from the unit body 15. Moreover, the switching unit 10 is filled within the casing 20 with a sealant 50 for covering the mounting surface side of the circuit board 11 and bus bar circuit 12, terminal of the switching device 13 and the entire part of the connection (soldering part). Accordingly, waterproofing property can be improved because adhesion of water or the like to the unit body 15 can be restricted. <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.
Further, when such a switching unit is mounted on an automobile, water or the like may be attached depending on the mounting position, and an improvement in waterproofness is also demanded.

  This invention is completed based on the above situations, Comprising: It aims at providing the switching unit which can be reduced in size and improved in waterproofness.

  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, and the switching device is connected to both of them, housed in a casing, and provided at the end of the bus bar circuit The connecting terminal extends integrally, and the casing is filled with a sealing agent that covers the circuit body.

  The invention of claim 2 is characterized in that, in the invention of claim 1, the casing is formed with an opening that opens upward from the filling region of the sealant.

  The invention of claim 3 is characterized in that, in the invention of claim 1 or 2, a plurality of the openings are formed on the wall surface of the casing.

  According to a fourth aspect of the present invention, there is provided the apparatus according to any one of the first to third aspects, further comprising a heat dissipating means for cooling the circuit body.

  According to a fifth aspect of the present invention, in the device according to the third aspect, the heat radiating means is disposed so as to be in close contact with a surface opposite to the surface where the circuit board of the bus bar circuit is in close contact. Has characteristics.

  According to a sixth aspect of the present invention, in the first or fourth aspect of the present invention, an insulating member is disposed between the connection terminal and the base plate from the circuit body. However, it has characteristics.

<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 structure for the internal circuit of the switching unit can be reduced in size.
Further, since the sealant covers the circuit body, it is possible to restrict water or the like from adhering to the circuit body on the switching unit.
As a result, according to the present invention, it is possible to improve the waterproof property while reducing the size of the switching device.

<Invention of Claim 2>
Since the opening part opened upwards rather than the filling area | region of a sealing agent is formed, injection | pouring of a sealing agent can be performed smoothly.

<Invention of Claim 3>
Since a plurality of openings are formed, it is possible to smoothly fill the sealant by using a part of them for injecting the sealant and using the other as an air vent.

<Invention of Claim 4>
Since the heat radiating means for cooling the circuit body is provided, the heat dissipation of the switching unit is further improved.

<Invention of Claim 5>
Since the heat dissipating means is closely attached to the bus bar circuit, the bus bar absorbs the heat generated on the circuit board side, and further the heat absorbed by the bus bar is transmitted to the heat dissipating means, so that the heat generated by the switching unit is quickly transmitted to the heat dissipating means. It is possible to further improve heat dissipation.

<Invention of Claim 6>
Since the switching unit is provided with an insulating member between the base end portion of the connection terminal and the heat dissipation means, even if the circuit body and the heat dissipation means are brought close to each other to reduce the size, a short circuit between the circuit body and the heat dissipation means. Can be reliably prevented, and heat radiation using the heat radiation means can be performed. As a result, the heat dissipation can be improved while downsizing the entire switching device.

<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 on the circuit board 11 side in which the circuit board 11 and the bus bar circuit 12 are in close contact with each other through an insulator (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 11, and the strength of the unit main body 15 can be secured by supporting the almost entire area of the circuit board 11 with the bus bar circuit 12. ing.
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.

  As shown in FIG. 2, a heat radiating plate (corresponding to “heat radiating means” of the present invention) 25 is provided below the unit main body 15. The heat radiating plate 25 is an aluminum metal plate and is adhesively bonded to the lower surface of the bus bar of the unit body 15 by applying an adhesive (for example, a silicone-based adhesive or an epoxy-based adhesive) or an adhesive sheet (for example, an adhesive on both sides of the insulating sheet). (The adhesive or adhesive sheet corresponds to the “insulator” of the present invention), and heat generated in the unit body 15 is transmitted through the bus bar circuit 12. It is heated and released to the outside. These adhesives can further improve heat conductivity by using a material containing a material having high thermal conductivity such as alumina filler.

Moreover, the insulating member 30 is arrange | positioned between the heat sink 25 in the base end part from the unit main body 15 of 12 A of connection terminals (refer FIG. 2).
The insulating member 30 is formed in a substantially prismatic shape with an insulating resin, and is fitted into a notch 26 formed at the end of the radiator plate 25 on the connection terminal 12A side (left side in FIG. 2). ing. The notch 26 is formed by cutting into a substantially prismatic shape in accordance with the shape of the insulating member 30 over the width direction of the heat radiating plate 25, and by fitting the insulating member 30, the upper surface (bus bar) The attachment surface of the circuit 12 is substantially flush with the upper surface of the insulating member 30. As a result, even when the upper surface of the heat radiating plate 25 and the lower surface of the bus bar circuit 12 are bonded, the bonding can be reliably performed without causing a step or the like. Even when a current flows through the connection terminal 12A, the insulating member 30 is interposed between the base end portion of the connection terminal 12A and the heat sink 25, so that the connection terminal 12A and the heat sink 25 are interposed between them. A short circuit or the like does not occur.

The casing 20 has a substantially rectangular parallelepiped shape as a whole, and the surface of the main body 21 on the side from which the connection terminal 12A is led out (left side in FIG. 2) can be closed with a separate lid body 22.
When the main body 21 accommodates the unit main body 15 therein, it can surround the entire circumference other than the lead-out side of the connection terminal 12A, and the inner wall thereof has a groove 23 corresponding to the heat sink 25 as shown in FIGS. Is formed. When the unit main body 15 is assembled to the casing 20, the heat sink 25 is inserted into the groove 23 and inserted while being slid, so that the unit main body 15 can be easily positioned and the assembling work can be performed smoothly. . Further, when the heat radiating plate 25 is assembled in the groove 23, the lower surface is brought into close contact with the inner wall surface of the main body 21, whereby a gap is formed between the heat radiating plate 25 and the inner wall of the casing 20. The generation of heat is controlled so that the heat of the heat radiating plate 25 is easily transmitted to the casing 20.
The lid body 22 has a flat plate shape as a whole, and is formed so that the outer peripheral diameter on the side of the main body 21 becomes small and can be fitted to the opening of the main body 21 (FIG. 4). FIG. 2). Further, the lid body 22 is formed with an insertion hole 24 at a position where the connection terminal 12A is led out. By fitting the connection terminal 12A into the insertion hole 24, the connection terminal 12A can be led out from the casing 20 without a gap. (See FIG. 3).

Now, in the switching unit 10 of this embodiment, the sealing agent 50 is filled in the casing 20.
The sealant 50 is made of silicone gel, epoxy resin, urethane resin, or the like, and is filled on the mounting surface side of the unit body 15 as shown in FIG. 2, and is mounted on the mounting surface side of the circuit board 11 and the bus bar circuit 12. And the terminal of the switching device 13 and the whole connection part (soldering part) are coat | covered.
And in this embodiment, in order to inject | pour said sealing agent 50, the opening part 35 is drilled in the cover body 22. As shown in FIG. The opening 35 penetrates in the plate thickness direction of the lid 22 above the filling region (see FIG. 2) of the sealing agent 50 on the side opposite to the insertion hole 24 of the lid 22 (upper side in FIG. 2). It is formed in this way.
Further, two openings 35 are provided on both the left and right sides of the lid body 22 (see FIGS. 3 and 7). Among these, one opening part 35 is used for injection | pouring of the sealing agent 50, and the other sealing part 50 can be inject | poured smoothly by using the other opening part 35 as an air vent. Further, as described above, since these openings 35 are arranged above the filling region of the sealant 50, the switching unit 10 is horizontally placed so that the heat radiating plate 25 comes to the lower surface as shown in FIG. It is possible to smoothly inject the sealant 50 in a state of being placed on the surface.

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, even when a current flows through the connection terminal 12A, the insulating member 30 is interposed between the base end portion of the connection terminal 12A and the heat sink 25, so that the connection terminal 12A and the heat sink 25 are interposed between them. The current can be reliably controlled without causing a short circuit or the like.
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, a complicated circuit such as a control system circuit that would increase in size when formed by the bus bar circuit 12 is formed on the circuit board 11, and a circuit for input / output and the connection terminal 12 </ b> A are integrated by the bus bar circuit 11. Since it forms, the structure for the circuit inside the switching unit 10 can be reduced in size, and the switching unit 10 can be reduced in size. In particular, it is possible to achieve a much higher density than that in which a circuit is formed only by a flat metal conductive path such as a bus bar.
Furthermore, since the sealing agent 50 covers the unit main body 15, it is possible to restrict water and the like from adhering to the unit main body 15, and the sealing agent 50 creates a gap between the insertion hole 24 of the lid body 22 and the connection terminal 12 </ b> A. Since it can be filled, the waterproof property of the switching unit 10 can be improved.
Further, even when the switching unit 10 is operated and placed at a low temperature in a high temperature state, even if so-called “condensation” occurs in which moisture in the air condenses and adheres to the surface, the unit main body 15 Is covered with the sealant 50 and does not come into direct contact with air, so that condensation forms on the surface of the unit main body 15 (the circuit board 11, the bus bar circuit 12 or the switching device 13, or a connecting portion thereof). Can be regulated. Thereby, it becomes possible to prevent the fall of the reliability resulting from dew condensation.

  Further, in this embodiment, the sealing agent 50 can be injected from the opening 35 formed in the lid 22, and two openings 35 are provided, and one of them is used for injection. Thus, by using the other as the air vent, the filling work of the sealant 50 can be performed smoothly.

Furthermore, in this embodiment, since the unit main body 15 is in close contact with the sealant 50 without an air layer, heat generated in the unit main body 15 such as the switching device 13 and the circuit board 11 passes through the sealant. It is transmitted to the casing 20 and can be discharged to the outside. Thereby, the heat dissipation of the switching unit can be improved.
Further, since the switching unit 10 includes the insulating member 30 between the base end portion of the connection terminal 12A and the heat radiating plate 25, the unit main body can be configured even if the unit main body 15 and the heat radiating plate 25 are brought close to each other to reduce the size. Therefore, it is possible to reliably prevent a short circuit between the heat sink 15 and the heat sink 25 and to perform heat dissipation using the heat sink 25.
Thereby, the heat dissipation can be improved while downsizing the entire switching unit 10.

  In addition, regarding the unit main body 15, for example, in the process before the mounting of the heat sink 25 in the manufacturing process, the strength is insufficient only by the circuit board 11, but in the unit main body 15 of the present embodiment, the circuit board 12 is almost entirely. Since the bus bar circuit 12 is pasted, sufficient strength can be ensured with the unit body 15 alone.

  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 heat radiation plate 25 is omitted and the connection terminal 12A is provided with a branch terminal 12B, but the same is true for other similar configurations. The duplicated explanation 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.
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.

<Embodiment 3>
Next, Embodiment 3 of the present invention will be described with reference to FIG.
The switching unit 10B of the present embodiment is different from the first embodiment in that the opening side is the lead-out side of the connection terminal 12A of the casing 20 (omitting the lid 22F that can be placed in the above embodiment). Is. Other similar configurations are denoted by the same reference numerals, and redundant description is omitted.
In the casing 20 according to this embodiment, the entire surface of the main body 21 on the side from which the connection terminal 12A is led out (the left side in FIG. 5) is the opening 35, and the unit main body 15 is assembled in the casing 20, The sealant 50 is poured into the casing 20 after facing upward. And if the sealing agent 50 is inject | poured to the opening edge of the opening part 35, the switching unit 10B which filled the sealing agent in the whole casing is manufactured by hardening the sealing agent 50 in the state as it is. .
Such a switching unit 10B can also be configured to have improved waterproofness and heat dissipation.
The casing 20 of the present embodiment is provided with a locking portion 27 at the opening edge of the opening 35 on the lower side in FIG.

<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 first and second embodiments, the sealing agent is filled up to the lower end edge of the injection hole. However, the present invention is not limited to this, and the sealing agent is filled in the entire interior of the casing 20 without a gap. It may be. In this case, as in the third embodiment, the entire inside of the casing 20 can be filled by filling the connection terminal 12A leading side, that is, the opening side of the injection hole upward.
(2) In the first and second embodiments, two openings 35 are formed in the lid, one of which is used for injecting the sealant and the other is used for venting air, but this is not the only case. Instead, for example, the insertion hole 24 of the lid 22 may be used as an air vent.
(3) In the above embodiment, the switching unit 10 or 10B of the first embodiment or the third embodiment may be provided with the branch terminal 12B as in the second embodiment, and the switching unit 10A of the second embodiment The connection terminal 12A may be applied instead of the branch terminal 12B.
Moreover, the casing 20 like Embodiment 3 may be applied with respect to the switching unit 10A which abbreviate | omitted the heat sink 25 like Embodiment 2. FIG.

(4) In the above embodiment, among the inner walls of the casing 20, the inner wall on the side where the heat sink abuts (in Embodiment 1 or 3) or the inner wall on the side where the lower surface side of the bus bar circuit 12 abuts (in Embodiment 2). It may be thinner than others. Thereby, heat dissipation can be improved.
Further, the heat dissipation of the entire casing 20 may be improved by using a resin in which a filler such as alumina is added to the resin constituting the casing.
(5) In the said embodiment, although the heat sink was accommodated in the inside of a casing, not only this but the heat sink 25 exposed to the exterior of the casing 20 may be used.
(6) In the above embodiment, the switching units 10, 10 </ b> A, and 10 </ b> B mount the semiconductor switching element on the switching device 13. However, the present invention is not limited to this, and for example, an IC or the like may be mounted.
(7) In the above embodiment, an IC, a microcomputer or the like may be mounted on the control system circuit.
(8) In the above embodiment, a structure in which a heat radiating means such as a heat radiating fin is added to the heat radiating plate may be used in order to further increase the heat radiating area.
(9) Although the semiconductor switching element is used for the switching device 13 in the above embodiment, the present invention is not limited to this, and a bare chip or the like may be mounted.
(10) Although the casing 20 is made of resin in the above embodiment, it 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 terminal fitting lead-out direction Exploded sectional view of switching unit Longitudinal section of the switching unit before injecting sealant Plan view viewed from the opening side of the casing body Top view of the lid viewed from the side facing the body Plan sectional drawing of the switching unit of Embodiment 2. Y-Y 'longitudinal section view of the switching unit A plan view from the connection terminal lead-out direction of the switching unit Plan sectional drawing of the switching unit of Embodiment 3.

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 25 ... heat sink (heat dissipating means)
30 ... Insulating member 35 ... Opening 50 ... Sealant

Claims (6)

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,
The connection terminal extends integrally at the end of the bus bar circuit,
A switching unit, wherein the casing is filled with a sealing agent that covers the circuit body. The switching unit according to claim 1, wherein the casing is formed with an opening that opens upward from a filling region of the sealant. The switching unit according to claim 1, wherein a plurality of the openings are formed on a wall surface of the casing. The switching unit according to any one of claims 1 to 3, further comprising a heat dissipating means for cooling the circuit body. 5. The switching unit according to claim 4, wherein the heat radiating means is disposed so as to be in close contact with a surface opposite to the surface with which the circuit board of the bus bar circuit is in close contact. 6. The switching unit according to claim 4, wherein an insulating member is disposed between the heat sink and a base end portion of the connection terminal from the circuit body.

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