JP2971699B2 - Electrical unit and method of assembling the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrical unit having improved durability and reduced manufacturing cost, and a method of assembling the same.

[0002]

2. Description of the Related Art An electrical unit mounted on a vehicle is used for various purposes from an air conditioning control device in a vehicle compartment to an electronic fuel injection control device, an anti-lock brake device or a navigation device. Efforts to achieve stable operation under constantly exposed environments or efforts to increase durability and reduce manufacturing costs at the same time have been continuously made. Some of these electrical units are located in the cabin, while others are located in the engine room, which is much more harsh in terms of vibration, temperature, or humidity than the cabin. The use environment greatly affects the product specifications and the manufacturing cost in connection with the durability of the individual elements.

The conventional electrical unit 1 shown in FIG. 3 has been developed mainly for use in an anti-lock brake device, mainly for use in a vehicle interior, and has an output stage screwed to a crank-shaped radiating plate 2a. A circuit block 2 in which a transistor 2b and other circuit components 2c, 2d, 2e, etc. are mounted on a glass epoxy substrate 3 is housed in aluminum cases 4, 5 which can be separated vertically. A connector 6 for inserting a socket (not shown) or the like from the outside is sandwiched between the lower case 4 and the upper case 5,
The end of the external connection lead terminal 6 a inserted into the connector 6 is soldered to a required portion of the glass epoxy board 3.

To assemble the electrical component unit 1, first, a circuit component 2e to be surface-mounted is mounted on a glass epoxy substrate 3 coated with cream solder for reflow soldering, and the circuit component 2e is melted by high-temperature heating. After soldering to the glass epoxy board 3, the circuit components 2a to 2d and the connector 6 are mounted, the connector 6 is screwed, and then passed through a solder layer and soldered. Further, a moisture-proof coating material is applied to the surface of the glass epoxy substrate 3 after the soldering, and after the moisture-proof coating material is dried, the glass epoxy substrate 3 is placed in the lower case 4. And
The glass epoxy board 3 is fixed to the lower case 4 by screwing a set screw to a screw fixing boss 4a integrally provided on the bottom surface of the lower case 4. Finally, the lower surface opening of the upper case 5 is matched with the upper surface opening of the lower case 4, and the upper case 5 is screwed to the lower case 4 to complete the electrical unit 1.

[0005]

The above-mentioned conventional electrical component unit 1 has a configuration in which a circuit component 2e is reflow-soldered on a glass epoxy board 3, so that the ambient temperature is as high as 40 degrees below zero as in an engine room. In a harsh environment assumed in the range of 120 degrees, there is a problem in terms of heat resistance and heat dissipation, and in an engine room where the engine vibration is transmitted more directly than in the vehicle interior, about 20 G of vibration However, the output stage transistor 2b and the like screwed to the heat sink 2a may be repeatedly vibrated, and the screws may loosen and fall off the glass epoxy substrate 3 due to repeated vibration. Transistor 2
Since b and some of the other circuit components are erected on the glass epoxy substrate 3, a certain amount of space must be secured above the heat sink 2a and the other circuit components 2b to 2e. It was difficult to make the entire unit compact in the height direction. Therefore, the conventional electrical unit 1 has a low mounting efficiency and is difficult to be miniaturized in the width or length direction. Further, the lower case 4 and the upper case 5 surround the circuit component accommodating space with the connector 6 sandwiched therebetween. Are screwed to each other, but they cannot completely prevent water droplets from entering the circuit component housing space, and the moisture-proof coating material is not effective for a large amount of water droplets. It was not suitable for use in muddy water intrusion environments.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a lower substrate on which circuit components are mounted, fixed to an inner wall surface of a lower case, and a lower lead extending from the lower substrate. A lower block whose terminals extend out of the lower case, and are integrally molded with the lower case of the lower block,
A connector for insulatingly holding a plurality of external connection lead terminals bonded to the lower substrate, and an upper substrate on which circuit components are mounted is fixed to an inner wall surface of an upper case, and the upper lead terminal extending from the upper substrate is An upper block extending out of the upper case and the upper case are fixed to the lower case by defining a circuit component accommodating space, and the lower lead terminal and the upper lead terminal are connected to each other by soldering. The electrical unit further includes a lid that is connected to the lower case and the upper case so as to cover a connection portion between the lower and upper lead terminals.

Further, according to the present invention, a lower substrate on which a circuit component is mounted is fixed to an inner wall surface of a lower case integrally formed with a connector for insulatingly holding a lead terminal for external connection. Bonding a terminal to the lower substrate, assembling a lower block in which a lower lead terminal extending from the lower substrate extends out of the lower case, and mounting the upper substrate on which circuit components are mounted to the upper case. Assembling an upper block that is fixed to an inner wall surface of the upper case and an upper lead terminal extending from the upper substrate extends out of the upper case; and defining the upper case as a circuit component accommodating space on the lower case. Fixing the lower block and the upper block by fixing, and soldering and connecting the lower lead terminal and the upper lead terminal to each other , And it is characterized in the assembly method of the electric unit to cover the connection portion of the lower side and the upper lead terminal comprising a step of coupling the lid to the lower case and upper case.

[0008]

According to the present invention, there is provided a lower block assembled by fixing a lower substrate to which a connector is connected to a lower case integrally formed with a connector, and an upper block assembled by fixing an upper substrate to an upper case. After the upper case is defined by defining a circuit component accommodating space and fixed to the lower case, the lower lead terminal and the upper lead terminal extending outside the case are connected to each other by soldering. By providing a lid to the lower case and the upper case so as to cover a connection portion of the upper lead terminal, a small and robust electrical unit excellent in heat dissipation, water resistance and vibration resistance is provided.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS.
This will be described with reference to FIG. FIG. 1 is a longitudinal sectional view showing an embodiment of the electrical unit of the present invention, and FIG. 2 is a process diagram showing an assembling process of the electrical unit shown in FIG.

The electrical unit 11 shown in FIG. 1 includes a lower block 12 and an upper block 13 which are separately assembled, and a connector 14 which is sandwiched between left ends of the blocks 12 and 13 and serves as an external connection interface. 13 and a cover 15 that covers the right end. Connector 1
Reference numeral 4 denotes a plurality of externally connected lead terminals 14a bent in a crank shape held in a resin molded body having a U-shaped cross section in two upper and lower rows. Is integrally molded with the lower case 16. On the upper surface of the lower case 16, a ceramic lower substrate 17 on which a circuit component 17a such as a bare chip is mounted is adhered by an adhesive, and the lower substrate 17 is bonded to the external connection lead terminals 14a. The connection is made via a wire 18. A waterproof resin 19 is poured into the inside of the lower case 16 up to the vicinity of the upper surface opening thereof.
Although the circuit components 17a on the base 7 are uniformly filled with the waterproof resin 19, only the lower lead terminals 20 extending from the right end of the lower substrate 17 have their tips protruding from the waterproof resin 19 and outside the lower case 16. Extend to

The upper block 13 has a ceramic upper substrate 22 having a circuit component 22a such as a bare chip mounted on the inner wall surface of an aluminum die-cast upper case 21 with an adhesive. Part 22a
And the waterproof resin 23 is poured to the vicinity of the opening of the upper case 21. However, only the upper lead terminal 24 extending from one end of the upper substrate 22 has a tip extending from the waterproof resin 23 and extending outside the upper case 21. The lower block 12 and the upper block 13 are united by forming the lower case 16 and the upper case 21 into a circuit component accommodating space 25 and bonding the lower case 16 and the upper case 21 to each other. The lead terminals 24 are connected to each other by soldering. The lid 15 is shaped to engage with the right ends of the lower case 16 and the upper case 21, and surrounds the soldered portions of the lead terminals 20, 24 to cover the lower case 16.
And the upper case 21 at the right end.

In assembling the electrical unit 11, first, the lower block 12 shown in FIG. 2A is assembled.
First, an aluminum die-cast lower case 16 serving as a base of the lower block 12 and the connector 14 are integrally molded.
Next, a ceramic lower substrate 17 on which a circuit component 17 a such as a bare chip is mounted is attached to the upper surface of the lower case 16. When the lower substrate 17 is fixed to the lower case 16, one side edge of the lower substrate 17 faces the end of the external connection lead terminal 14 a held by the connector 14 except for a bonding connection distance. The lower lead terminal 20 extending from the other side edge of the lower substrate 17 rises along the side edge of the lower case 16, bends at a right angle at the upper end of the lower case 16, and extends outside the lower case 16. Put out. Then, the end of the external connection lead terminal 14a held by the connector 14 is bonded to a predetermined position on one side edge of the lower substrate 17 using a bonding connection device or the like. Finally, the waterproof resin 19 is poured into the inside of the lower case 16 to protect the circuit components 17a from water droplets and to enhance the holding force of the components when subjected to vibration. Since the waterproof resin 19 is injected into the vicinity of the upper surface opening of the lower case 16, the lower substrate 1
Although the circuit components 17a on the chip 7 are uniformly filled with the waterproof resin 23, only the lower lead terminals 20 extending from the right end of the lower substrate 17 have their tips coming out of the waterproof resin 19 and outside the lower case 16. Extend to The lower block 12 of the electrical unit assembled in the above process is connected to a lower lead terminal 20 with an inspection device (not shown), and only those that pass the inspection are used for mounting.

On the other hand, when assembling the upper block 13 shown in FIG. 2B, a circuit component 2 such as a bare chip is placed on the upper surface of an aluminum die-cast upper case 21 serving as a base.
An upper substrate 22 made of ceramic on which 2a is mounted is attached. When the upper substrate 22 is fixed to the upper case 21,
An upper lead terminal 24 extending from one side edge of the upper substrate 22 rises along the side edge of the upper case 21, bends at a right angle at the upper end of the upper case 21, and extends outside the upper case 21. Therefore, the waterproof resin 23 is poured into the inside of the upper case 21 to impart water resistance and vibration resistance. Waterproof resin 23
Is injected into the vicinity of the upper surface opening of the upper case 21, so that the circuit components 22 a on the upper substrate 22 are uniformly filled with the waterproof resin 23, but only the upper lead terminals 24 extending from the right end of the upper substrate 22. The tip extends out of the upper case 21 from the waterproof resin 23. The upper block 13 of the electrical unit assembled in the above process
Also, an inspection device (not shown) is connected to the upper lead terminal 24, and only those that pass the inspection are provided for mounting.

The lower block 12 thus separately assembled
2 and the upper block 13, the upper case 21 and the lower case 16 are vertically opposed to each other as shown in FIG. 2 (C), and the joint surfaces of the two cases 16, 21 and the contact surface to the connector 14 are bonded with an adhesive. Glue and combine. At this time, both cases 16,
Lead terminals 20 and 24 extending outside from 21 are in a state where the tips are in light contact with each other. Therefore, the lead terminals 20,
24 are electrically connected by soldering. As a result, the upper substrate 22 of the upper block 13 is connected to the lower substrate 17 of the lower block 12 via the upper lead terminals 24 and the lower lead terminals 20, and the bonding wires 1
8, the external connection lead terminal 14 in the connector 14
a.

When the soldering of the lead terminals 20 and 24 is completed, finally, as shown in FIG. 2D, the cover 1 is covered so as to cover the soldered portions of the lead terminals 20 and 24.
5, and the electrical unit 11 is completed. In the completed electrical unit 11, it is necessary to determine the quality of the bonding connection between the external connection lead terminal 14a and the lower substrate 17 and the soldering position between the lower lead terminal 20 and the upper lead terminal 24. (Not shown) to connect to connector 14 for inspection device
And conduct a continuity test.

As described above, the electrical unit 11 includes the substrates 17 and 22 for mounting the circuit components 17a and 22a.
Are opposed to each other on the lower side and the upper side.
Since the bare chips 7a and 22a themselves can be mounted in small volumes close to bare like a bare chip, the mounting space of the circuit components 17a and 22a can be made as small as possible to make the whole unit compact. Further, since the substrates 17 and 22 are fixed to the lower case 16 and the upper case 21, respectively, good heat radiation is possible by direct heat conduction using a wide heat radiation area. In addition, since the connector 14 is integrally molded with the lower case 16, there is no need for assembling the connector 14 to the lower case 16, so that the assemblability is excellent, and the connection between the connector 14 and the lower case 16 can be improved. Does not require special waterproofing measures. Furthermore, as long as the lower case 16 and the upper case 21 are properly bonded to each other, there is no danger of rainwater, muddy water or the like entering from the outside. Since 14a is connected to the lower substrate 17 by the bonding wire 18, even if a force due to thermal stress or vibration is generated, the bonding wire 18 absorbs such stress, so that a connection failure does not occur. Accordingly, it is possible to provide a compact and robust electrical component unit 11 having excellent heat dissipation, water resistance, and vibration resistance.

Furthermore, since both the lower substrate 17 and the upper substrate 22 are made of ceramic and the lower case 16 and the upper case 21 are both made of aluminum die-cast, both the lower substrate 17 and the upper substrate 22 have a wide temperature range. The rate of high-temperature melting and low-temperature shrinkage in a changing severe environment is small, and it is hard to cause a shape change or the like. In addition, since the ceramic itself has a very high thermal conductivity, the substrates 17, 2
It is not necessary to attach a heat radiating plate or the like to the circuit components 17a, 22a mounted on the substrate 2, and the heat transmitted through the ceramic substrates 17, 22 is directly radiated to the outside through the aluminum die-cast cases 16, 21. Therefore, heat is not confined in the cases 16 and 21. Therefore, even when used in a harsh environment such as in an engine room, the circuit components 17a, 22 mounted on the substrates 17, 22 are provided.
There is no fear that a is destroyed by high heat exceeding the normal temperature.

Further, the lower case 16 and the upper case 21
Then, waterproof resin 19,2 is covered by covering the built-in substrates 17 and 22.
3 when injected in an environment exposed to rainwater or muddy water, such as in an engine room,
Even if water drops enter the cases 16 and 21, the substrate 1
There is no direct harm to the circuit components 17a, 22a mounted on the substrates 7, 22, and the circuit components 17a, 22a mounted on the substrates 17, 22 are hardened by the waterproof resins 19, 23. 20G transmitted to the room
The circuit components 17a and 22a do not fall off even if the vibrations are applied to the circuit, and stable circuit operation is assured.

[0019]

As described above, according to the present invention, the lower substrate is bonded to the external connection lead terminal held by the connector and assembled to the lower case integrally formed with the connector. The block and the upper block assembled by fixing the upper substrate to the upper case are integrated by fixing the upper case to the lower case while defining a circuit component accommodation space, and the lower lead terminal extending outside the case. After soldering and connecting the upper and lower lead terminals to each other, the lower and upper lead terminals are connected so that the lid is joined to the lower case and the upper case to cover the connection points, so that circuit components can be mounted. The circuit boards are arranged facing each other up and down, and the circuit components themselves can be mounted in a small volume almost bare like a bare chip. Can be made compact overall bets, it was fixed to the substrate in the case, but may be better heat dissipation by direct heat conduction with a large heat radiation area,
Also, since the connector is integrally molded with the lower case,
There is no need to attach the connector to the lower case,
Because of its excellent assemblability, no special waterproof measures are required between the connector and the lower case.Furthermore, as long as the lower case and the upper case are properly bonded to each other, the rainwater There is no danger of intrusion of muddy water or muddy water, and the external connection lead terminals held by the connector are connected to the lower substrate by bonding wires. However, since it absorbs such stress, it does not lead to poor connection, thereby providing an excellent effect such as providing a small and robust electrical unit excellent in heat dissipation, water resistance and vibration resistance. Play.

Further, according to the present invention, the lower and upper substrates are preferably
Both are made of ceramic and the lower and upper cases are made of aluminum die-cast, so even if the lower and upper substrates are used in a severe environment where the temperature changes over a wide range, they may melt at high temperatures or shrink at low temperatures. The rate of change is small, the shape change can be reduced, and the ceramic itself has a very high thermal conductivity, so there is no need to attach a heat sink to circuit components mounted on the board, and The heat transmitted through the substrate is radiated to the outside via the aluminum die-cast case as it is, so the heat is not confined in the case, so even if used in a harsh environment such as in the engine room, This has the effect that there is no fear that the circuit components mounted on the substrate will be destroyed by high heat exceeding the normal temperature.

Further, according to the present invention, since at least one of the lower case and the upper case covers the substrate fixed to the inner wall surface and is infused with a waterproof resin, rainwater or muddy water as in an engine room. When used in an environment exposed to the penetration of water, even if water drops enter the case, the circuit components mounted on the board will not be directly harmed, and the circuit components mounted on the board will not Because it is hardened with waterproof resin, even if vibrations of up to 20G transmitted to the engine room are applied, there is no danger that circuit components will fall off, and it is possible to always ensure stable circuit operation. To play.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of an electric unit of the present invention.

FIG. 2 is a process diagram showing an assembly process of the electrical unit shown in FIG.

FIG. 3 is a longitudinal sectional view showing an example of a conventional electrical unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Electrical unit 12 Lower block 13 Upper block 14 Connector 14a External connection lead terminal 15 Lid 16 Lower case 17 Lower substrate 17a Circuit component 18 Bonding wire 19 Waterproof resin 20 Lower lead terminal 21 Upper case 22 Upper substrate 22a Circuit component 23 Waterproof resin 24 Upper lead terminal 25 Circuit component accommodation space

Claims (5)

(57) [Claims] A lower block on which a lower substrate on which a circuit component is mounted is fixed to an inner wall surface of a lower case, and a lower lead terminal extending from the lower substrate extends out of the lower case;
A connector molded integrally with the lower case of the lower block and insulatingly holding a plurality of external connection lead terminals bonded and connected to the lower substrate, and an upper substrate on which circuit components are mounted on an inner wall surface of the upper case. An upper block that is fixed and has an upper lead terminal extending from the upper substrate extending outside the upper case; and a circuit component accommodating space for fixing the upper case to the lower case. After the terminal and the upper lead terminal are connected to each other by soldering, a lid is provided which covers a connection portion between the lower and upper lead terminals and is coupled to the lower case and the upper case. Electrical unit. 2. The electrical unit according to claim 1, wherein the lower and upper substrates are both made of ceramic, and the lower and upper cases are made of aluminum die-cast. 3. At least one of the lower case and the upper case includes a waterproof resin injected to cover the substrate fixed to an inner wall surface and circuit components mounted on the substrate. The electrical component unit according to claim 1. 4. A lower substrate on which a circuit component is mounted is fixed to an inner wall surface of a lower case integrally formed with a connector for insulatingly holding an external connection lead terminal, and further, the external connection lead terminal and the lower terminal are connected to each other. Bonding the lower substrate to the side substrate, assembling a lower block in which a lower lead terminal extending from the lower substrate extends out of the lower case, and mounting the upper substrate on which the circuit components are mounted on the inner wall surface of the upper case. Assembling an upper block in which an upper lead terminal extending from the upper substrate extends out of the upper case, and fixing the upper case to the lower case by defining a circuit component accommodating space. Integrating the lower block and the upper block; soldering and connecting the lower lead terminal and the upper lead terminal to each other; Connecting the lid to the lower case and the upper case so as to cover the connection portion of the lead terminal. 5. At least one of the step of assembling the lower block and the step of assembling the upper block includes covering the substrate fixed to an inner wall surface and a circuit component mounted on the substrate with a waterproof resin. 5. The method of assembling an electrical unit according to claim 4, further comprising the step of injecting.