JP4783054B2 - 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.
In addition, such a switching unit may not be usable if a connection terminal for connection to the outside hits another member and is damaged. In particular, in the case of repeatedly attaching and detaching, the connection terminal may be damaged.

  The present invention has been completed based on the above-described circumstances, and an object thereof is to provide a switching unit capable of downsizing and protection of connection terminals.

As means for achieving the above object, the invention of claim 1 is provided with a switching device capable of controlling on / off of current and a connection terminal for connection to the outside. In a switching unit that is detachably assembled, a circuit body having a circuit board and a bus bar circuit that are in close contact with each other via an insulator and having the switching device connected to both of them is housed in a casing. A housing for integrally extending the connection terminal at an end of the bus bar circuit, surrounding a side of the connection terminal in a fitting direction, and a heat radiating plate for cooling the circuit body. the provided, on the casing, the housing is formed integrally, such as to close the other direction of fitting with the mating of the connection terminals Rutotomoni, the cable The ring, the which grooves fitted into the end portion of the heat radiating plate is formed, the surface of the heat radiating plate which is fitted into the groove is in close contact with the inner wall surface of said casing, said in the casing It is characterized in that it is filled with a sealing agent that covers the circuit body.

According to a second aspect of the present invention, in the bus bar circuit according to the first aspect, the overall shape of the bus bar circuit is substantially the same as that of the circuit board, and a region covering substantially the entire circuit board is defined by the bus bar circuit. It has the feature in the place where it supports .

According to a third aspect of the present invention, in the first or second aspect of the present invention, the heat radiating plate is disposed so as to be in close contact with a surface opposite to the surface of the bus bar circuit where the circuit board is in close contact. It has the characteristics in the place.

According to a fourth aspect of the present invention, in the device according to any one of the first to third aspects , a notch portion is formed at an end of the heat radiating plate on the connection terminal side. It is characterized in that an insulating member is fitted in the notch.

<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.
Furthermore, since the housing which encloses the side of the fitting direction of the connection terminal is provided, it can control that other members collide with the connection terminal unexpectedly.
Thereby, according to this invention, protection of a connection terminal is attained, aiming at size reduction of a switching device.
In addition, since it is formed integrally with the casing, the number of parts is reduced, and the connection terminals other than the fitting direction are closed, so that the waterproof and dustproof properties are excellent.
Furthermore, since the sealing agent covers the circuit body, it is possible to restrict water and the like from adhering to the circuit body in the switching unit and to improve waterproofness.
Moreover, since the heat sink for cooling a circuit body is provided, the heat dissipation of a switching unit improves more.

<Invention of Claim 3 >
Since the heat sink is placed in close contact with the bus bar circuit, the bus bar absorbs the heat generated on the circuit board side and further transfers the heat absorbed by the bus bar to the heat sink, so the heat generated by the switching unit is quickly transferred to the heat sink. It is possible to further improve heat dissipation.

<Invention of Claim 4 >
Since the switching unit is equipped with an insulating member at the end of the heat sink connecting terminal, the short circuit between the circuit body and the heat sink can be ensured even when the circuit body and the heat sink are placed close together. Therefore, it is possible to radiate heat using a heat radiating plate. As a result, the heat dissipation can be improved while downsizing the entire switching device.

<Embodiment 1>
Embodiment 1 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 includes a main body 21 that accommodates the unit main body 15 therein. The main body 21 has a substantially rectangular parallelepiped shape, and when the unit main body 15 is accommodated therein, the entire periphery other than the connection terminal 12A lead-out side can be surrounded. The inner wall of the main body 21 has a heat sink 25 as shown in FIG. Corresponding grooves 23 are 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 casing 20 of the present embodiment is provided with a locking portion 27 at the opening edge on the lower side of FIG. 2 of the opening for inserting the unit main body 15 of the main body 21 so as to prevent the unit main body 15 from being removed. It has become.

Further, the inside of the main body 21 of the casing 20 is filled with a sealant 50.
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 it is filled so that the terminal of the switching device 13 and the whole connection part (soldering part) may be 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.

Now, in the casing 20 of this embodiment, a housing 28 is disposed on the lead-out side of the connection terminal 12A.
The housing 28 has a hood shape that opens to the left side of FIG. 2, on the lead-out side of the connection terminal 12 </ b> A (in the direction of fitting with a mating terminal fitting not shown), and is formed integrally with the main body 21 of the casing 20. And has a closed structure with respect to directions other than the opening side. Further, the left end of the housing 28 in FIG. 2 extends to the left side from the front end of the connection terminal 12A, and can surround the entire connection terminal 12A.

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.
Further, the switching unit 10 is provided with a housing 28, and the entire connection terminal 12A including the tip of the connection terminal 12A is enclosed before the switching unit 10 is mounted on the other side. It is possible to regulate damage caused by contact with a member or the like.
In addition, the switching unit 10 of the present embodiment is in a closed state with respect to a direction other than the connection terminal 12A lead-out side, and the connection terminal 12A lead-out side is also closed by being attached to the other side. Therefore, it becomes possible to improve waterproofness, dustproofness, etc.

Furthermore, in this embodiment, 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 is connected to the insertion hole 24 of the lid body 22 and the connection terminal. Since the gap with 12A 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.

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 covered. Since the bus bar circuit 12 is pasted, sufficient strength can be secured even with the unit main body 15 alone.

  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.

<Embodiment 2>
Next, a second embodiment of the present invention will be described with reference to FIG.
Although the switching unit 10A of the present embodiment is different from the first embodiment in that the switching unit 10A includes a lid 22 that closes the opening of the main body 21 of the casing 20, the same reference numerals are given to other similar configurations. A duplicate description is omitted.
The lid body 22 has a flat plate shape as a whole, and is formed so as to be fitted into the opening of the main body 21 (see FIG. 4). Further, when the lid body 22 is assembled to the main body 21, the lead-out side surface of the connection terminal 12A of the housing 28 is formed to be flush with the main body 21. Further, the lid body 22 is formed with an insertion hole 24 at a position where the connection terminal 12A is led out. By inserting 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).
As described above, according to the switching unit 10A of the present embodiment, in addition to the operational effects of the first embodiment, the lid 22 holds the unit body 15 particularly when the switching unit 10A is removed, so that the durability of the switching unit 10A is improved. Will improve.

<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 side of the connection terminal 12A of the main body 21 of the casing 20 is closed with a wall surface and the opposite side is an opening. Is. Other similar configurations are denoted by the same reference numerals, and redundant description is omitted.
According to the switching unit 10B having such a configuration, the force acting on the unit main body 15 at the time of removal is received by the casing 20, so that the durability of the switching unit 10B is improved.
Further, since the unit body 15 can be assembled to the casing 20 from the side opposite to the housing 28, workability is improved.

<Embodiment 4>
Next, a fourth embodiment of the present invention will be described with reference to FIG.
The switching unit 10C of the present embodiment is different from the third embodiment in that the opening on the side facing the lead-out side of the connection terminal 12A of the main body 21 of the casing 20 is closed by the lid 22. It is. Other similar configurations are denoted by the same reference numerals, and redundant description is omitted.
According to such a structure, the unit body 15 can be held by the casing 20 both when the switching unit 10C is inserted and withdrawn, so that the durability of the switching unit 10C is improved.

<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 main body 21 and the housing 28 of the casing 20 are integrated, but may be separate.
(2) In the above embodiment, the casing 20 may be formed so as to seal the unit main body 15 by molding. According to such a thing, it becomes possible to improve waterproofness, without using the sealing agent 50 in the said embodiment.
(3) In the above embodiment, the heat radiating plate 25 is provided. However, the present invention is not limited thereto, and the heat radiating means such as the heat radiating plate 25 may be omitted.
(4) In the above embodiment, the inner wall of the casing 20 on the side on which the heat sink 25 abuts may be thinner than the other. 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, 10A, 10B, and 10C are those in which a semiconductor switching element is mounted 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 Exploded sectional view of switching unit Longitudinal sectional view of the switching unit of the second embodiment Longitudinal sectional view of the switching unit of Embodiment 3 Longitudinal sectional view of a switching unit according to Embodiment 4

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)
28 ... Housing 30 ... Insulating member 50 ... Sealant

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, and detachably assembled to an electrical junction box,
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 housing for enclosing the sides of the fitting direction of the connection terminal,
A heat sink for cooling the circuit body,
Grooves in said casing, said housing is formed integrally, said such to close the non-fitting direction of the mating connection terminal Rutotomoni, the casing, which fitted into the end portion of the heat radiating plate The surface of the heat sink fitted in the groove is in close contact with the inner wall surface of the casing,
A switching unit, wherein the casing is filled with a sealing agent that covers the circuit body. 2. The switching according to claim 1, wherein the bus bar circuit has a substantially rectangular shape similar to that of the circuit board, and the bus bar circuit supports a region covering substantially the entire circuit board. unit. 3. The switching unit according to claim 1 , wherein the heat radiating plate is disposed so as to be in close contact with a surface opposite to a surface where the circuit board of the bus bar circuit is in close contact . The cutout part is formed in the edge part by the side of the said connecting terminal of the said heat sink, The insulation member is engage | inserted by this notch part, The Claim 1 thru | or 3 characterized by the above-mentioned. The switching unit according to one item .

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