JPS5846660A - Manufacture of heat sink - Google Patents

Abstract

PURPOSE:To increase the height of two fins, and to form the heat sink, the space of the fins thereof is small, while obtaining the heat sink having the large capacity of radiation by a method wherein a fin member, which has two fins and a reinforcing section connecting the fins and a ladder-shaped section, is extruded and worked, stacked and fixed to a mounting section. CONSTITUTION:The fin members 11 formed by integrally extruding and working the two fins 11A, 11B and the reinforcing sections 11C connecting sections among the fins are arranged between a pair of the mounting sections 10, and the brazing sheets 12 of both-surface solder material clad are positioned, brazed and fixed among each end surface and the mounting sections 10. Bosses 11D with width wider than size among the outer surfaces of the fins are integrally formed at both ends of the fin members 11, the spaces d of the fins can be set arbitrarily, and thickness t can severally be selected properly in conformity with the mode of use because the mounting sections 10 are worked separately.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a heat sink for mounting transistors and the like.

In electronic equipment such as communication equipment and AC-DC converters, transistors, ICs, etc. that generate heat and are affected by heat are mounted on heat sinks to prevent runaway or even breakdown by suppressing their own temperature rise. It prevents you from doing so.

Equipment with a large output capacity requires a heat sink with a correspondingly large heat dissipation capacity.

As shown in FIG. 1, a conventional heat sink is generally made by extruding aluminum metal material with high thermal conductivity, and integrally molds a mounting portion l having a mounting surface IA for a transistor, etc., and heat dissipation fins 2.

However, according to the extrusion processing method, the height h and pinch P of the fin 2 are limited by the extrusion device. This cannot be done without making it inappropriately thick, and the pitch P also becomes large. This makes it difficult to obtain the desired large capacity heat dissipation performance.

For this purpose, for example, as shown in Fig. 2, a groove 1' is formed in the mounting part 1 for the transistor, etc., and a fin plate 2 is planted in this groove 1' and bonded with a synthetic resin with excellent heat conductivity. Brazing is a known method of fixing. However, this method requires complicated assembly work, and the reliability of heat transfer between the mounting portion 1 and the fin plate 2 is low. Furthermore, in the case of brazing, the thickness of the fin plate 2 is thinner and longer than the mounting part 1, so when it is heated to the brazing temperature, the fin plate 2 is thermally deformed as shown by the dashed line. It is difficult to avoid ending up with an undesirable shape. Conventionally, there was no suitable brazing jig to avoid this problem. Furthermore, as shown in FIG. 3, a method is known in which nine fin plates 2 are stacked by bending their edges 2A, and are brazed to the mounting portion 1 via a plating sheet 3. It is difficult to avoid the drawback of deformation as shown by the dashed line. In order to prevent deformation of the fin plate 2, for example, as shown in FIG. 4, if a plate 2' clad with brazing metal on both sides is used to increase the rigidity as a honeycomb structure, the number of joints increases and the assembly work becomes complicated. In this case, the excess solder protrudes beyond the joint and increases the resistance to passage of fluid through the joint. In addition, in either method, there is a high possibility that the bonded portion will peel off, and problems such as abnormal noises may occur in the vibrating part of the cooling fan or the like.

The present invention aims to eliminate these drawbacks of the prior art and provide a manufacturing method that can easily manufacture a heat sink with a large heat dissipation capacity.

In order to keep this in mind, the manufacturing method of the present invention involves extruding a fin member having a roughly ladder-like cross section, which has two fins and a reinforcing portion that connects both fins with a space between them. The fins are arranged so that there is a fin spacing between adjacent fin members and are fixed to the mounting part. In other words, problems such as pitch when extruding a large number of fins as one body can be solved by combining two fins. This problem can be solved by extruding only the fins, and by forming a reinforcing part between two fins, it is possible to extrude long fins.

The reinforcement portion increases the rigidity of the fin member to prevent thermal deformation during soldering.

A preferred embodiment of a heat sink manufactured by the manufacturing method of the present invention will be described below with reference to FIGS. 5 to 8.

The heat sink shown in FIG. 5 has a fin member 11 formed by integrally extruding two fins A and IIB and a reinforcing part 11C connecting them between a pair of mounting parts 10.
are arranged side by side, and a plating sheet 12 made of double-sided brazing material cladding is interposed between each end face and the mounting portion 10 to securely braze them. In this way, it is possible to use a thin plate made only of brazing material instead of the double-sided brazing material cladding, or to use a thin plate made of only brazing material, or
.

It is possible to avoid the use of a single-sided braze metal clad plate and no plating sheet. In this heat sink, for example, a transistor (not shown) is attached to the mounting surface 10A.
be attached by known means.

Although not shown, it is preferable that the heat sink be cooled by blowing air in a direction perpendicular to the paper surface using a cooling fan.

This fin member 11 is integrally formed with a boss 11D wider than the dimension between the outer surfaces of the fins at both ends, and by stacking each fin member 11 with the sides of the boss in close contact with each other, the fin spacing between each fin member can be adjusted. d can be determined. Therefore, the fin spacing d between the fin members can be arbitrarily (finely) set without being subject to manufacturing restrictions. Since the mounting portion 10 for fixing the fin member 11 is processed separately, the wall thickness t can be appropriately selected depending on the usage mode.

Here, to explain the extrusion process of the fin member 11, since it has a substantially ladder-like cross section with the reinforcing part 11Ct, the existence of the reinforcing part 11C has a favorable effect on the metal flow, and the fin length is The length can be made very long.

For example, the thickness t' of the fin IIA and the reinforcing part 11C is 1
It has been confirmed that the fin member 11 can be formed with a fin spacing d' of about 2 m and a fin length h of about 120 m by extrusion.

According to the manufacturing method of the present invention in which such a fin member 11 is extruded and brazed between a pair of attachment parts 10, the bending rigidity of the fin member 11 is significantly increased, and the tightening force during brazing is reduced. Also, deformation of the fin IIA due to heating can be avoided. Furthermore, by increasing the pressing force, the reliability of adhesion and fixation can also be improved. Furthermore, the manufactured heat sink has a narrow interval between the fins IIA and a large fin length h, so that the heat dissipation capacity is greatly improved. FIG. 6 shows another embodiment of the fin member. This fin member has a protrusion 20A that fits into the side end of the boss 20 at the end.
and a recessed portion 20B is formed. The formation of such protrusions 20A and recesses 20B has the effect of facilitating the work of stacking the fin members. Further, since the fin member is extruded, the processing accuracy of the protrusions and recesses is low, and the adhesion to the mounting portion is not deteriorated.

FIG. 7 1) shows an embodiment in which a protrusion 30B other than the reinforcing portion 30A is further formed on the fin 30 of the fin member. This protrusion 30B is designed to uniform the passage resistance of the cooling fluid and to prevent the flow of metal during extrusion. By forming the protrusions 30B at appropriate locations in this manner, it is possible to form the fins 30 that are denser and longer.

As explained above, the manufacturing method of the present invention involves extruding a fin member with a ladder-like cross section having two fins and a reinforcing part connecting them, stacking them together and fixing them to a mounting part. By extruding the fin member, the fin height can be increased, and a heat sink with small fin spacing can be formed, so a heat sink with a large heat dissipation capacity can be obtained, and manufacturing costs can be reduced by simplifying the assembly work.

In the present invention, for example, as shown in FIG. 8, a concave portion 40A is formed in the end face of the boss 40, and the fin member has a structure in which the force during brazing and tightening is absorbed by the legs of the boss. The shape can be changed in various ways.

[Brief explanation of drawings]

1 to 4 are side views showing the structure of a conventional heat sink. FIG. 5 is a sectional view showing an embodiment of a heat sink manufactured by the manufacturing method according to the present invention. FIG. 6 is a partially enlarged sectional view of a 747 member according to another embodiment. FIG. 7(a) and FIG. 7(b) are a partial sectional view and a sectional view showing an assembled state of a fin member according to still another embodiment. FIG. 8 is a partially enlarged sectional view showing an end portion of a fin member according to still another embodiment. 1.10・・・・・・・・・・・・Mounting part 2.2
′・・・・・・・・・・・・・・・・・・Fin plate 11・・・・・・・・・・・・・・・・・・Fin member □ 11A, 11B, 30... Fins 11C, 30A... Reinforcement parts 11D, 20
．． 40...Boss 30B...Protrusion patent applicant Nippon Light Metal Co., Ltd. Patent applicant Patent attorney Ryosan Electric Co., Ltd. Taku Watanabe Filial 7th figure (b
)

Claims (1)

[Claims] (By extruding a fin member having a roughly ladder-like cross section, which has 122 fins and a reinforcing portion that connects both fins to each other, the fin members are juxtaposed and fixed to a mounting portion. A method of manufacturing a heat sink. (2) A method of manufacturing a heat sink. (2) A method of manufacturing a heat sink. A method for manufacturing a heat sink according to scope 1. (3) Forming a protrusion and a recess that fit into each other on the side surface of a boss of the fin member, and positioning the fin member to be stacked by fitting the protrusion and the recess. A method for manufacturing a heat sink according to claim 2, characterized in that the heat sink is provided with a cooling fluid (air, etc.) in the fins of the fin member.
According to any one of claims 1 to 3, a protrusion is formed in addition to the reinforcing part in order to uniform the passing resistance of the metal and to improve the flow of metal during extrusion processing. Method of manufacturing the heat sink described.