JPH0444346A - Sealed hybrid circuit device - Google Patents

Abstract

PURPOSE:To prevent loss of an external appearance due to the flowout of filler and to improve reliability by engaging a heat dissipating fin with the inner periphery of a rib reduced in diameter of a resin case body, sealing the opening of one end side, and sealing the opening of the other end side with a cover. CONSTITUTION:A cylindrical resin case body 11 reduced in diameter by a rib 11c protruding toward the inner wall of one end side 11a is employed, the diameter-reduced part of a heat dissipating fin 12 formed in a protruding section is so attached as to be fitted in the inner periphery of the rib 11c of the body 11, and the diameter-increased part is so adhesively integrated as to be fitted the inner periphery of the lower side of the rib 11c of the body 11. An opening of the other end side 11b of the case 11 is sealed with a cover 17. The fin 12 is connected to be double sealed with the case 11, and the opposed surface or connected surface of the fin 12 to the case 11 is largely increased. Accordingly, in manufacturing steps, even if ambient temperature vulcanized silicone is put in the case, flowout of the silicone out of the case 11 is entirely suppressed to exhibit an excellent external appearance, thereby forming and holding in an excellent sealability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a sealed hybrid circuit device, and more particularly to an improvement of a resin case sealed hybrid circuit device equipped with radiation fins.

(Prior Art) In consideration of functional reliability and stability, hybrid circuit devices having a structure in which a so-called hybrid circuit device main body is sealed within a resin case have been put into practical use in various electronic devices. In addition, in the resin case sealed hybrid circuit device, when an electronic component such as a power transistor that generates heat at a relatively high temperature is mounted, a heat dissipating material made of a material with good thermal conductivity such as Cu or Al may be used. The structure is such that the fins are attached to the back side of the circuit board.

That is, in a plan view as shown in FIG. 2(a), and as shown in FIG. 2(b).
As shown in cross section, a cylindrical resin case body 1, a radiation fin 2 sealing an opening 1a at one end of the resin case body 1, and a heat radiation fin 2 fixed to the inner surface of the radiation fin 2 with an adhesive 3 or the like. For example, a thick film circuit board 4 which has been made into A resin case-sealed hybrid circuit device comprising a cured material 6 made of room temperature vulcanizable silicone, for example, and a cover 7 for sealing the opening 1b at the other end of the resin case body 1. It has been known. In the figure, 8 is a lead terminal.

The resin case-sealed hybrid circuit device is generally constructed by the following procedure. That is, the heat dissipating fin 2 is first adhered to the opening 1a at one end of the cylindrical resin case body 1 using an adhesive and sealed. The one end opening 1a of the cylindrical resin case body 1 may be sealed by the radiation fins 2 when the cylindrical resin case body 1 is molded.

Next, on the inner surface of the heat dissipation fin 2 which was bonded and potted,
A thick film circuit board 4 on which necessary electronic components 5 such as power transistors, chip resistors, chip capacitors, etc. are mounted and mounted is attached and fixed with an adhesive 3 or the like. In this case, the dimensions of the thick film circuit board 4 are generally set smaller than the dimensions of the radiation fins 2 exposed inside the resin case body 1.

Thereafter, the resin case body 1 containing the thick film circuit board 4 on which the electronic components 5 are mounted and mounted is filled with, for example, room temperature vulcanizable silicone and cured 6. After covering or molding the electronic component 5 and the thick film circuit board 4 on which it is mounted and mounted in this manner, the cover 7 is glued to the opening 1b at the other end of the resin case body 1. It has a sealed structure.

(Problems to be Solved by the Invention) However, in the case of the resin case sealed hybrid circuit device having the above structure, the following disadvantages are recognized. That is, the heat dissipation fin 2 is glued to the opening 1a at one end of the cylindrical resin case body 1 using an adhesive. However, since it is practically difficult to strictly bond the heat dissipation fin 2 to the opening 1a at one end of the cylindrical resin case body 1, it will not be necessary to do so later. As a process, it is necessary to replenish the adhesive at the part (part of the corner) where the upper surface of the heat dissipation fin 2 and the inner wall surface of the resin case body 1 contact each other to seal the gap, which makes the work complicated.

On the other hand, when the heat dissipation fins are integrally molded when molding the cylindrical resin case body 1, the difference in thermal expansion coefficient between the thermoplastic resin forming the resin case body 1 and the AI, Cu, etc. forming the heat dissipation fins causes molding. Due to the difference in subsequent shrinkage rates, gaps occur at the joint surfaces.

Therefore, when using the room temperature vulcanizable silicone as a filler to coat or mold the electronic component 5 housed inside the resin case body 1 and the thick film circuit board 4 on which it is mounted/mounted, the filled room temperature vulcanizate silicone is used as a filler. silicone etc.
There is a problem that the resin flows out of the resin case main body 1 through the minute gap due to a so-called capillary phenomenon, spoiling the appearance, and in some cases not achieving a sufficient airtight sealing function.

The present invention has been made in response to the above-mentioned circumstances, and aims to provide a sealed hybrid circuit device that is prevented from deteriorating its appearance due to leakage of the filler and has high functional reliability.

[Structure of the Invention] (Means for Solving the Problems) The sealed hybrid circuit device of the present invention includes a cylindrical resin case main body whose diameter is partially reduced by a rib protruding from an inner wall surface on one end side; a heat dissipation fin that partially fits into the inner circumferential surface of the rib whose diameter is reduced in the resin case body and seals the opening on the one end side; a circuit board that is attached and fixed to the inner surface of the heat dissipation fin; A necessary electronic component mounted and mounted on a circuit board surface, a filler filled to cover the electronic component and the circuit board surface, and a cover for sealing an opening on the other end side of the resin case body. It is characterized by comprising:

(Function) In the sealed hybrid circuit device according to the present invention,
The heat dissipation fin on which the circuit board is placed on the top surface is held in a manner that fits into the inner peripheral surface of the rib whose diameter is reduced on the resin case body, and the main part of the sealed container is It makes up the department. In other words, the heat dissipation fins that make up the bottom part are joined in a stepped manner by the side wall of the resin case body and the ribs, and the joint surface is large, which prevents the filler from flowing out due to capillary action. . Therefore, damage to the appearance due to the leakage of the filler is also prevented, and good airtightness is maintained, resulting in high functional reliability.

(Example) The present invention will be described in detail below with reference to FIG.

FIG. 1 shows a cross-sectional view of a configuration example of a resin case-sealed hybrid circuit device according to the present invention, and 11 is a cylinder whose diameter is partially reduced by a rib lie protruding from the inner wall surface of one end side 11a. The main body is a shaped resin case.

12 is a rib that reduces the diameter of the resin case body 11;
This is a heat dissipation fin that partially fits into the inner circumferential surface and seals the opening on the one end side 11a.

The radiation fins 12 have a convex cross section, and the reduced diameter part is bonded to the inner circumference of the resin case body 11 by fitting into it, and the expanded diameter part is attached to the inner circumferential surface of the resin case body 11.
The pot body is glued so as to fit into the lower inner peripheral surface of the rib lie. In other words, the heat dissipation fins 12 constituting the bottom surface are joined in a stepped manner by the side wall of the resin case body 11 and the ribs 11c.

Reference numeral 14 denotes a circuit board mounted and fixed on the inner surface of the radiation fin 12 with an adhesive 13 or the like, and 15 indicates the required electronic components 1 mounted and mounted on the surface of the circuit board 14.
5. For example, IC chips, chip capacitors, chip resistors, etc. Furthermore, 16 is a filler filled to cover the electronic component 15 and the circuit board 14 surface, such as a silicone rubber layer, and 17 is a cover that seals the opening on the other end side 11b of the resin case body 11. It is.

The sealed hybrid circuit device having the above configuration uses a cylindrical resin case main body 11 whose diameter is partially reduced by a rib llc protruding from the inner wall surface of one end side 11a, and a convex cross section as the radiation fin 12. Using the configuration,
The reduced diameter part of the radiation fin 12 is connected to the rib l of the resin case body 11.
It is glued so that it fits on the inner peripheral surface of the LC, and the expanded diameter part is glued so that it fits on the inner peripheral surface on the lower side of the rib lie of the resin case body 11.
It can be easily manufactured by conventional manufacturing means except for the step of making a pot.

In the sealed hybrid circuit device according to the present invention, the joint between the radiation fin 12 and the resin case body 11 is
It is set on the back surface of the circuit board 14 to be installed. In other words, the radiation fins 12 and the resin case body 11 are doubly bonded and sealed, and the contact surface or the surface to be joined between the radiation fins 12 and the resin case body 11 is also significantly enlarged. Therefore, even when room temperature vulcanizable silicone is used as a filler in the manufacturing process, leakage out of the case body is completely suppressed or prevented, resulting in a good appearance. Moreover, since good airtightness is formed and maintained, functional reliability is also improved.

In addition, although room temperature vulcanization type silicone was illustrated as a filler above, it is needless to say that it is not limited to this.

[Effects of the Invention] As can be seen from the above description, the resin case-sealed hybrid circuit device according to the present invention not only can be finished with a good appearance, but also can form and maintain good sealing. A hybrid circuit is capable of stably performing the required functions at all times.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of the structure of a sealed hybrid circuit device according to the present invention, and FIGS. 2(a) and (b) are views showing the structure of a conventional sealed hybrid circuit device. 2(a) is a plan view, and FIG. 2(b) is a sectional view. 111...Case body la, lla...One end side opening part l of the case body
b, Ilb...Other end side opening part li of the case body
e・・・・・・・Rib of case body 2.12・・・・
・Radiation fin 3.13...Adhesive 14...Circuit board 15...Electronic component 16...Filler 17...Sealing cover

Claims (1)

[Claims] A cylindrical resin case body whose diameter is partially reduced by a rib protruding from an inner wall surface on one end side, and a part of the resin case body is fitted into the inner peripheral surface of the rib whose diameter is reduced to form an opening on the one end side. a heat dissipation fin for sealing, a circuit board mounted and fixed on the inner surface of the heat dissipation fin, required electronic components mounted and mounted on the circuit board surface, and covering the electronic components and the circuit board surface. 1. A sealed hybrid circuit device comprising: a filler filled with a resin material; and a cover for sealing an opening on the other end side of the resin case main body.