Heat sink for electronic parts and manufacture thereof

United States Patent Application 20020043359

Kind Code:

A1

Heat dissipation fins 12 provided on a metal flat plate 10 with a predetermined distance and a metal base plate provided with a plurality of bottom-expanded recesses 15 on the flat surface 14 with a predetermined distance are prepared and pressing portions corresponding to the bottom-expanded recesses on the flat plate between fins to press down protrusions provided on the back side of the flat plate into the bottom-expanded recesses to fix the heat dissipation fins and the base plate securely. Number of components of the heat sink is reduced and construction has become simple. The manufacturing cost is reduced.

Inventors:

Mizutani, Kazuo (Chiyoda-ku, JP)

Application Number:

09/814291

Publication Date:

04/18/2002

Filing Date:

03/21/2001

View Patent Images:

Download PDF 20020043359 pdf

PDF help

Export Citation:

Click for automatic bibliography generation

Assignee:

Mizutani Electric Ind. Co., Ltd.

Primary Class:

29/890.030

Other Classes:

165/80.300, 165/185

International Classes:

(IPC1-7): B21D053/02; F28F007/00

Attorney, Agent or Firm:

MERCHANT & GOULD PC (P.O. BOX 2903, MINNEAPOLIS, MN, 55402-0903, US)

Claims:

What is claimed is:

1. A heat sink for electronic parts comprising: a plurality of heat dissipation fins provided on a metal flat plate with a predetermined distance, a metal base plate provided with a plurality of bottom expanded recesses on the flat surface with a predetermined distance, pressing a portion corresponding to the bottom-expanded recesses provided on the flat surface between the fins to press down protrusions provided on the back side of the metal flat plate to press into the bottom-expanded recesses to fix the heat dissipation fins and the base plate securely.

2. A heat sink for electronic parts comprising: a plurality of heat dissipation fins provided on a metal flat plate with a predetermined distance, a metal base plate provided with a plurality of bottom-expanded recesses on the flat surface with a predetermined distance, and the base plate provided with a holding protrusions to hold both ends of the heat dissipation fins. pressing the portion corresponding to the bottom-expanded recesses of the metal flat plate between fins and to press the protrusions provided on the back side of said flat plate to press into said bottom-expanded recesses and to press the holding protrusions provided on the edges of the base plate toward the side of the heat dissipation fins to fix said heat dissipation fins and the base plate securely.

3. A manufacturing process of a heat sink for electronic parts comprising: a plurality of heat dissipation fins provided on a metal flat plate with a predetermined distance and a metal base plate provided with a plurality of bottom-expanded recesses on the flat surface with a predetermined distance are prepared, and pressing a portion corresponding to the bottom-expanded recesses of the flat plate between the fins to press down protrusions provided on the back side of the flat surface plate to press into the bottom-expanded recesses to fix the heat dissipation fins and the base plate securely.

4. A manufacturing process of a heat sink for electronic parts comprising: a plurality of heat dissipation fins provided on a metal flat plate with a predetermined distance, a metal base plate provided with a plurality of bottom-expanded recesses provided on the metal flat surface with a predetermined distance, and the base plate provided with a holding protrusions to hold at both ends of the plate, pressing the portions corresponding to the bottom-expanded recesses of the flat plate between fins and to press down the protrusions provided on the back side of said flat plate into said bottom-expanded recesses and to press the holding protrusions provided on the base plate toward the side of the fins to fix the heat dissipation fins and the base plate securely.

Description:

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a heat sink for electronic parts and more particularly relates to a heat sink for electronic parts made of Transistor, IC, LSI, Diode or Thyristor to cause heat during practical operation, the heat being conducted and dissipated from the heat sink fins.

[0003] 2. Prior Art

[0004] Conventional heat sink made of aluminum has been disclosed in the Japanese Patent Publication No. 3-40506. Reference is made with FIG. 1 to explain such conventional heat sink. A substrate 1 made of aluminum and heat dissipation fins 2 formed by bending aluminum band sheets into the rectangular corrugated plate are soldered to prepare a heat sink. In the process of manufacturing heat sink, two vertically protruded edge frames 3 , 3 provided in parallel with each other at each edge of the substrate 1 respectively are formed on the substrate 1 with a predetermined distance. The heat dissipation fins are placed between said oppositely faced protruded edge frames 3 , 3 . As shown in FIG. 1 , the heat dissipation fins extend to a full width between the protruded edge frames 3 , 3 provided on the substrate 1 in parallel with each other, and a portion of the protruded edge frame 3 where the heat dissipation fins 2 and said protruded edge frame 3 come into contact with each other is pressed by means of a mold to stretch out said portion toward inside the substrate 1 . Reference numeral 3 a indicates the portion stretched out inside the substrate 1 in FIG. 1 . The portions 3 a , 3 a secure the heat dissipation fins 2 to the substrate 1 . Next, the substrate 1 and the heat dissipation fins 2 are soldered together.

[0005] It has been pointed out in the conventional method that the heat dissipation fins 2 and the substrate 1 are to be soldered because if the heat dissipation fins 2 are secured to the substrate 1 only by means of the aforementioned portions 3 a , 3 a , the heat dissipation fins 2 will not perfectly contact the substrate 1 and the heat generated in the substrate 1 is not perfectly conducted to the heat dissipation fins 2 .

[0006] It is, therefore, required in the conventional manufacturing method of heat sink to solder the heat dissipation fins 2 to the substrate 1 . However, in order to proceed the soldering process some soldering installments are inevitably required. This is a problem in conventional method.

[0007] Further, as bending the aluminum band sheet into a rectangular corrugated sheet makes the heat dissipation fins, plate thickness of the heat dissipation fins is limited to be thinner taking into consideration of easy handling. Accordingly, if the heat dissipation fins made of thinner plate should collide other materials such as electronic parts or housings or the like, the fins are easily distorted.

[0008] The present invention has been made with the foregoing background in mind. The object of the present invention is to offer an easy processing method and yet most durable heat sinks for electronic parts and manufacture thereof.

SUMMARY OF THE INVENTION

[0009] In order to achieve the aforementioned object the present invention offers a heat sink disclosed in claim 1 and illustrated in FIG. 2A and 2B . The heat sink according to the present invention comprises a plurality of heat dissipation fins 12 and a base plate 16 . The heat sink includes heat dissipation fins 12 provided with a plurality of fins 11 placed on the upper surface of a metal plate 10 with a predetermined distance, and the metal base plate 16 provided with a plurality of bottom-expanded recesses 15 on the upper surface of a flat plate 14 with a predetermined distance. Portions corresponding to the bottom-expanded recesses 15 of the flat plate 14 between the fins 11 are pressed by means of a mold 18 so that protrusions 13 (refer to FIG. 3 B 2 ) provided on the back side of the metal plate 10 are pressed into the bottom-expanded recesses 15 to fix the heat dissipation fins 12 and the base plate 16 together.

[0010] The invention disclosed in claim 2 comprises, as briefly illustrated the overall construction in FIG. 4A, 4B , 4 C, heat dissipation fins 12 provided with a plurality of fins 11 placed on the upper surface of the flat plate 10 with a predetermined distance and a metal base plate 16 provided with a plurality of bottom-expanded recesses 15 on the upper surface of a flat plate 14 with a predetermined distance and protrusions 17 , 17 to hold the side edges of said heat dissipation fins 12 to secure said heat dissipation fins 12 on the upper surface of a flat plate 14 . Portions of the flat plate 10 corresponding to the bottom-expanded recesses 15 between said two fins 11 are pressed by the mold 18 to press down protrusions 13 (refer to FIG. 3 B 2 ) provided on the back side of said flat plate 10 into said bottom-expanded recesses 15 and the protrusions 17 , 17 formed on the base plate 16 are pressed and distorted toward the side of the heat dissipation fins 12 to fix said heat dissipation fins 12 to the base plate 16 .

[0011] The invention disclosed in claim 3 comprises heat dissipation fins 12 provided with a plurality of fins 11 placed on the upper surface of the metal plate 10 with a predetermined distance and a metal base plate 16 provided with a plurality of bottom-expanded recesses 15 on the upper surface 14 with a predetermined distance, and the portions of the flat plate 10 corresponding to the bottom-expanded recesses 15 between said two fins 11 are pressed by the mold 18 to press down protrusions 13 (refer to FIG. 3 B 2 ) provided on the back side of said flat plate 10 into said bottom-expanded recesses 15 to fix the dissipation fins 12 and the base plate 16 together. This is the manufacturing process of the heat sink disclosed in claim 1 .

[0012] The invention disclosed in claim 4 comprises the heat dissipation fins 12 provided with a plurality of fins 11 placed on the upper surface of the metal plate 10 with a predetermined distance and a metal base plate 16 provided with a plurality of bottom-expanded recesses 15 provided on the upper surface 14 with a predetermined distance and protrusions 17 , 17 to hold the side edges of the heat dissipation fins 12 to secure said heat dissipation fins 12 on the upper surface of a flat plate 14 . Portions of the flat plate 10 corresponding to the bottom- expanded recesses 15 between said two fins 11 are pressed by the mold 18 to press down protrusions 13 provided on the back side of said flat plate 10 into said bottom-expanded recesses 15 and the protrusions 17 , 17 formed on the base plate 16 are pressed and distorted toward the side of the heat dissipated fins 12 to fix said heat dissipated fins 12 to the base plate 16 . This is the manufacturing process of the heat sink disclosed in claim 2 .

BRIEF EXPLANATION OF THE DRAWINGS

[0013] FIG. 1 is a perspective view of the conventional aluminum heat sink.

[0014] FIG. 2 indicates a heat sink for electronic parts disclosed in claim 1 according to the present invention.

[0015] FIG. 3 illustrates a manufacturing process for the heat sink for the electronic parts disclosed in claim 3 according to the present invention.

[0016] FIG. 4 indicates a heat sink for the electronic parts disclosed in claim 2 according to the present invention.

[0017] FIG. 5 illustrates a manufacturing process for the heat sink for the electronic parts disclosed in claim 4 according to the present invention.

[0018] FIG. 6 indicates another example of the preferred embodiments for the heat sink for the electronic parts disclosed in claim 2 according to the present invention.

[0019] FIG. 7 indicates a cross-section partly cut the heat sink for the electronic parts disclosed in claim 2 according to the present invention.

DETAILED EXPLANATION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

[0020] Now an example of the preferred embodiments of the heat sink disclosed in claim 1 according to the present invention is explained with reference to the accompanying drawing FIG. 2A, 2B and 2 C.

[0021] FIG. 2A indicates a perspective view of the heat sink according to the present invention. FIG. 2B indicates a perspective view of the base plate. FIG. 2C indicates a perspective view of the heat sink for the electronic parts comprising the heat dissipation fins are pressed by the mold to fix the heat dissipation fins to the base plate. The heat sink according to the present invention is prepared by extruding a metal of good heat conduction such as aluminum or the like. The heat sink comprises heat dissipation fins 12 provided with a plurality of fins 11 formed on the flat metal plate 10 with a predetermined distance and a base plate 16 provided with a plurality of bottom-expanded recesses 15 formed on the flat plate 14 with a predetermined distance. As shown in FIG. 2 C, the portions corresponding to the bottom expanded recesses 15 on the flat surface 14 between the fins 11 are pressed down by means of the mold 18 to press down protrusions 13 (refer to FIG. 3 B 2 ) provided on the back side of said flat metal plate 10 into said bottom-expanded recesses 15 to fix said plurality of heat dissipation fins 12 and the base plate together. The bottom-expanded recesses 15 are made like dovetail grooves in the embodiments of the present invention. It is of course possible to form a recessed hole of dovetail groove. The recessed hole of dovetail groove configuration is not made by means of press extrusion but other extrusion method is applied. Reference numeral 18 a indicates protrusions to press and distort the flat metal plate 10 provided on the mold

[0022] As aforementioned, the heat sink according to the present invention is made by pressing down the protrusions 18 a provided in the mold 18 to press the corresponding portions to the bottom-expanded recesses 15 of the flat metal plate 10 between the fins 11 to press down said protrusions 13 into the bottom-expanded recesses 15 to fix the heat dissipation fins 12 to the base plate 16 . The soldering installation is not required. Thus, manufacturing cost is reduced.

[0023] The heat sink for electronic parts disclosed in claim 2 of the present invention is explained with reference to the drawings FIG. 4A, 4B and 4 C. FIG. 4A is a perspective view of the heat sink. FIG. 4B is a perspective view of the base plate. FIG. 4C is a perspective view of the heat sink for electronic parts prepared by pressing the heat sink to the base plate by means of the mold. The heat sink for electronic parts comprises a heat sink provided with a plurality of heat dissipation fins 12 formed on the surface of the flat metal plate 10 with a predetermined distance and the base plate 16 provided with the protrusions 17 , 17 to hold the both ends of said heat dissipation fins 12 on the surface of the flat plate 14 with a predetermined distance to hold together with the plurality of bottom-expanded recesses 15 . The corresponding portion to the bottom-expanded recesses 15 on the flat plate 10 between the fins 11 is pressed down by means of the mold 18 to press the protrusions 13 provided on the back side of the flat metal plate 10 into said recesses 15 (refer to FIG. 5 B 2 ). The holding protrusions 17 , 17 formed on the edge plate 16 are pressed and distorted toward the side of the heat dissipation fins 12 to fix said heat dissipation fins 12 and the base plate 16 tightly to prepare heat sink for electronic parts according to the present invention.

[0024] Reference numeral 18 b indicates a press protrusion to press and distort the holding protrusions 17 . It is possible to construct the heat dissipation fins 12 and the base plate 16 simply and perfectly fixed together without soldering. Both edges of the heat dissipation fins 12 are held firmly by being held with the protrusions 17 , 17 . The heat dissipation fins 12 and the base plate 16 are fixed tightly. A durable construction is obtained.

[0025] In this embodiment, two protrusions 17 , 17 are formed to hold the both ends of the heat dissipation fins 12 facing with each other. It goes without saying that holding another both ends of the heat dissipation fins 12 by additional protrusions 17 , 17 provided crossing at right angle to the edge side protrusions 17 , 17 can offer more durable structure of heat dissipation fins (not shown in figure).

[0026] The manufacturing process of the heat dissipation fins disclosed in claim 3 according to the present invention is explained with reference to the accompany drawing FIG. 3 A 1 , 3 A 2 , 3 B 1 and 3 B 2 . Firstly, the heat sink is prepared by extruding a metal of good heat transmission such as aluminum or the like. The heat sink comprises heat dissipation fins 12 provided with a plurality of fins 11 formed on the plate 10 with a predetermined distance and a base plate 16 provided with a plurality of bottom-expanded recesses 15 formed on the flat plate 14 with a predetermined distance. As shown in front view of FIG. 3 A 1 and right side view of FIG. 3 A 2 , a plurality of heat dissipation fins 12 are provided on the base plate 16 . Next, as shown in front view of FIG. 3 B 1 and right side view of FIG. 3 B 2 , the corresponding portion of the flat plate 10 to a plurality of bottom-expanded recesses 15 between the fins 11 are pressed down by means of the mold 18 to press insert the protrusions 13 provided on the back side of the flat plate 10 into the bottom-expanded recesses 16 to fix said heat dissipation fins 12 and said base plate 15 securely.

[0027] In accordance with this manufacturing process of the heat sink for electronic parts, said heat dissipation fins 12 and the base plate 16 are perfectly fixed without soldering. The manufacturing process is simple but securely fixed construction is obtained. The manufacturing cost is reduced. The manufacturing process of the heat sink for electronic parts disclosed in claim 4 is explained with reference to FIG. 5 A 1 and 5 A 2 . At first, the heat dissipation fins 12 provided with a plurality of fins 11 on the flat plate 10 with a predetermined distance and the base plate 16 provided with a plurality of the bottom expanded recesses 15 formed on the plate surface 14 with a predetermined distance and further provided with the holding protrusions 17 , 17 to hold the edges of said heat dissipation fins 12 are prepared by extruding a metal of good heat conduction such as aluminum. Next, as shown in front view of FIG. 5 A 1 and right side view of FIG. 5 A 2 , the corresponding portions on the flat plate 10 between the fins 11 to the bottom-expanded recesses 15 are pressed down by means of the mold 18 to press insert said protrusions provided on the back side of said flat plate 10 into the bottom-expanded recesses 15 and at the same time the holding protrusions 17 , 17 provided on the base plate 16 to press and distort said protrusions 17 , 17 toward the side of the heat dissipation fins 12 .

[0028] The heat dissipation fins 12 and the base plate 16 are fixed as aforementioned. The heat sink for electronic parts according to the present invention is prepared without soldering. The heat dissipation fins 12 and the base plate 16 are fixed together. A durable construction is obtained. If holding protrusions 17 , 17 are pressed to distort toward the side of the heat dissipation fins 12 , the fins 11 are strongly supported and the heat dissipation fins 12 are tightly held to the base plate 16 .

[0029] FIG. 6A, 6B and 6 C indicate another example of the preferred embodiments of the present invention. FIG. 6A is a perspective view of the heat dissipation fins 12 . FIG. 6B is a perspective view of the base plate 16 . FIG. 6C is a perspective view of the heat sink for electronic parts prepared by pressing the heat dissipation fins 12 toward the base plate 16 . FIG. 7 is a partly vertical cross-section of the heat sink shown in FIG. 6 . In this embodiment, the heat sink is pressed at the portions corresponding to said bottom expanded recesses 15 of the flat plate 10 between fins 11 , 11 by means of the mold 18 to press down the protrusions provided on the back side of the flat plate 10 into the bottom expanded recesses 15 and the holding protrusions 17 , 17 provided on the base plate 16 are slightly bent toward the side of the heat dissipation fins 12 . The portion 17 a is pressed down to cover the edges of the flat plate 10 of the heat dissipation fins 12 . As shown in FIG. 6 C, the press mold 18 is devised to press down the portion 17 a between the fins 11 of the holding protrusion 17 to cover the flat plate 10 of the heat dissipation fins 12 (e.g. dividing the press protrusion 18 b of the mold 18 ).

Effect of the Invention

[0030] As aforementioned, claim 1 (heat sink) and claim 3 (manufacturing method of the heat sink) present a heat sink by pressing the portion corresponding to the bottom-expanded recesses of the flat plate between the fins by means of the mold to press the protrusions provided on the back side of the flat plate toward the base plate to press down the protrusions into the bottom-expanded recesses. The perfectly fixed construction of the heat dissipation fins and the base plate is obtained. The manufacturing process is done without soldering installation. The manufacturing cost is greatly reduced.

[0031] As aforementioned, claim 2 (heat sink) and claim 4 (manufacturing method of the heat sink) present a heat sink by fixing the heat dissipation fins and the base plate without soldering. The heat dissipation fins are fixed at its ends to the base plate with the holding protrusions. Construction of the heat dissipation fins with the base plate is firm.