JP2573813B2 - Heat sink and its pressure casting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat sink (heat sink) used for cooling semiconductor devices and the like, and a pressure casting apparatus for manufacturing the heat sink.

[0002]

2. Description of the Related Art As a heat radiator of this type, a radiator formed from an extruded profile, a radiator formed by cold forging, or a profile having a predetermined sectional shape is cut out.

[0003] For example, a heat sink 101 of an extruded shape type
As shown in FIG. 16, a large number of fins 102, 102,... Are formed by cutting a long profile extruded into a predetermined cross-sectional shape. 101 is suitable for mass production because it has excellent productivity.

[0004]

The extruded-type radiator 101 described above is excellent in productivity, but is limited in the pitch and height of the fins 102, so that an improvement in the radiation efficiency cannot be expected. In addition, the cold forging type radiator also has limitations on the pitch and height of the pins due to limitations in the manufacturing method, which can satisfy the demand for higher density of fins to improve heat radiation efficiency. Can not.

Further, even if the number and size of the fins can be changed arbitrarily,
There is a problem that the cost is increased due to an increase in the number of processing steps.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides a structure of a radiator plate with improved heat radiation efficiency, and a pressure casting apparatus most suitable for manufacturing the radiator plate. It is intended to be.

[0007]

According to a first aspect of the present invention, there is provided a structure of a radiator plate formed by a pressure casting method, wherein a plurality of radiator pins are erected on an upper surface of a base plate and each radiator pin is radiated. The pin is formed in a tapered shape in which the cross-sectional area gradually decreases from the base toward the tip, and a single or a plurality of pins along the axial direction on the outer periphery of at least a part of the plurality of heat radiation pins. The fins are formed so as to project.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, the plurality of heat radiation pins are located on a plurality of concentric circles.

According to a third aspect of the present invention, a heat sink having a large number of tapered heat sink pins, each having a gradually decreasing cross-sectional area gradually decreasing from the root to the tip, is formed on the upper surface of the base plate by pressure casting. An apparatus for casting, comprising a lower mold and an upper mold in which mold clamping and mold opening operations are performed using a position corresponding to an upper surface of a base plate, on which a large number of heat radiation pins are projected, of a heat sink as a mold mating surface. In addition, a product space corresponding to the base plate is formed on the lower mold side, and a product space corresponding to the large number of heat radiation pins is formed on the upper mold side.

The upper mold is divided into a plurality of mold elements each having an engaging projection on a peripheral edge thereof with a vertical plane passing through the center of the plurality of heat radiation pins of each row among a large number of heat radiation pins. An upper die body that forms a product portion space corresponding to a number of heat radiation pins, and a housing hole that houses the upper die body is formed at a center portion, and a peripheral edge of the housing hole has the above-described shape of each of the mold elements. An outer mold formed with a stepped portion for engaging with the engagement protrusion and supporting a plurality of mold elements inserted from above the accommodation hole; and a plurality of mold elements mounted on the upper surface of the outer mold. A backup plate for restraining the upper die body, and an extrusion pin disposed above the backup plate and having a number of push pins inserted into the product portion space of the upper die body at positions corresponding to the heat radiation pins. With the unit The extrusion pin unit is divided into a plurality of comb-shaped pin pieces for each of a plurality of heat radiation pins formed by a pair of adjacent mold elements, and according to mold clamping and mold opening operations. When the mold is opened by raising and lowering, an extruding plate is formed to project each heat radiation pin from the upper mold body.

According to a fourth aspect of the present invention, in addition to the configuration of the third aspect, while a large number of heat radiation pins are set to be located on a plurality of concentric circles, the upper die body has the concentric circle. It is characterized in that it is divided into a plurality of mold elements, and the extrusion pin unit is divided into a plurality of pin pieces for each of the plurality of heat radiation pins on each concentric circle.

[0012]

According to the structure of the present invention, since a large number of radiating pins erected on the base plate are formed in a tapered shape, a large radiating area can be secured, and at the same time, the sectional area of each radiating pin in the axial center direction can be secured. A temperature gradient corresponding to the change can be provided, thereby improving the heat radiation efficiency. In addition, since at least some of the heat radiation pins are formed with the fins protruding, the heat radiation area is further increased, and the heat radiation efficiency is further improved.

According to the structure of the pressure casting apparatus of the present invention, the upper die body is divided into a plurality of mold elements, and the extrusion pin unit is divided into a plurality of pin pieces. If the main body is disassembled into mold elements, the part corresponding to each heat radiation pin in the product part space on the upper mold side will be released, so that the upper mold processing such as polishing will be easier and the surface The roughness can be increased. In this way, the molten metal can be prevented from adhering to the upper mold, and if a specific mold element is damaged, it can be dealt with only by replacing the mold element at that part alone. Similarly, when a specific pin piece is broken, it can be dealt with only by replacing only the pin piece at that portion.

[0014]

FIG. 1 is a view showing an embodiment of a radiator according to the present invention. The radiator 1 is integrally formed by a molten metal forging method using aluminum as a material. That is, the heat radiating plate 1 has a large number of heat radiating pins 3, 3... Erected at equal pitches on a rectangular base plate 2 so as to form a row in a vertical direction and a horizontal direction, respectively. Are formed as truncated pyramids whose cross-sectional area gradually decreases from the base side toward the tip end side. The inclination angles of the heat radiation pins 3, 3,... Also serve as draft angles at the time of casting, and are set to, for example, about 1.5 degrees. As shown in FIG. 1 (B), thin fins 4 protrude from two outer surfaces of the heat radiation pins 3, 3... Along the axial direction thereof. (However, in FIG. 1A, the fins 4 are not shown in order to avoid complicating the drawing). The fins 4 are also provided with the same draft angle as the radiation pins 3, 3,.

Therefore, according to the structure of the heat sink 1 of the present embodiment, since a large number of heat sink pins 3, 3,... At the same time as ensuring the conductivity and a large heat radiation area, the heat radiation pins 3, 3... Themselves have a smaller cross-sectional area at the tip end, so that the ratio of the length to the cross-sectional area can be increased. A temperature gradient can be positively provided in the longitudinal direction of 3, 3,..., Thereby improving heat radiation. Moreover, since a plurality of fins 4 are provided along the longitudinal direction on the outer periphery of each of the heat radiation pins 3, 3,..., A wider heat radiation area can be secured, and heat radiation is further improved.

In this case, the fins 4 may be provided on all four outer peripheral surfaces of the heat radiation pins 3, 3,..., As shown in FIG. Furthermore, it is not always necessary to provide the fins 4 on all the radiating pins 3, 3... On the base plate 2, and the fins 4 are set so as not to cause wind resistance particularly when air is blown to the radiator 1 for forced cooling. I do. Furthermore, the fins 4 need not be provided over the entire height of the heat radiation pins 3, 3,..., For example, as shown in FIGS. 4A may be set, and the heat radiation pins 3, 3,... Themselves may be, for example, truncated cones other than truncated pyramids.

FIG. 5 is a view showing another embodiment of the radiator 1 of the present invention. As shown in FIG. 5, the radiator 1 is provided with a fan unit 5 for blowing air. Are protruded only at positions not interfering with the fan unit 5. In the heat sink 1 shown in FIG. 5, all the heat sink pins 3, 3,... Are provided with fins 4 (however, only some of the fins 4 of the heat sink pins 3 are shown in FIG. The fins 4 of the heat radiating pins 3 are not shown), and as described above, the number and position of the heat radiating pins 3 where the fins 4 are provided or the number of the fins 4 themselves can be appropriately selected according to the air blowing characteristics from the fan unit 5. Needless to say.

FIG. 6 shows the heat radiation pins 3 and 3.
.. Are arranged on a plurality of concentric circles a to d with regularity, and fins 4 are formed only on the heat radiation pins 3, 3,. However, in the drawing, the fins 4 are shown only for some of the heat radiation pins 3, 3,... On the circle c, and the fins 4 of the other heat radiation pins 3, 3,. In the case of the embodiment shown in FIG. 6, the same operation and effect as those of the first embodiment can be obtained.

FIG. 7 shows a configuration of a pressure casting apparatus for casting the radiator 1 shown in FIG. 1 by a molten metal forging method. A mold 11 includes an upper mold 12 as a fixed mold and a movable mold as a movable mold. The upper and lower dies 12, 13 are clamped and opened with mold matching surfaces 12a, 13a corresponding to the upper surface of the base plate 2 of the heat sink 1.

The lower mold 13 has a product space 1 for molding a portion corresponding to the base plate 2 of the heat sink 1.
The lower die main body 15 having the lower die 4 and a lower die holder 16 for holding the lower die main body 15 are provided.

On the other hand, the upper die 12 includes an upper die body 17 having a product part space 16 for forming portions of the heat sink 1 corresponding to the respective numbers of the heat radiation pins 3, 3,. In addition to an outer die 18 for supporting the outer die 18, an upper die holder 19 for fixing and supporting the outer die 18, a backup plate 20 disposed on the upper surface of the outer die 18, and an extrusion disposed above the backup plate 20 Plate 21
And so on.

The upper die body 17 is provided with a heat sink 1 shown in FIG.
Have a concave product part space 16 corresponding to each of the heat radiating pins 3, 3,..., But the upper die body 17 has a large number of heat radiating pins 3, 3,. Fin 4
Are divided into a plurality of mold elements 22, 22,... With a vertical surface from a parting line e passing through the center of each row in the projecting direction. As shown in FIGS. 8 and 9, these mold elements 22, 22,... Are formed with a half-shaped concave portion 23 to be a product space of the heat radiation pins 3, 3,. The same half-shaped guide hole 24 that communicates
Are formed, and as shown in FIG. 10, the plurality of mold elements 22, 22,.
7 are formed, and the upper die body 17 composed of the plurality of die elements 22, 22,... Is fixedly held by being inserted into the accommodation hole 25 from the upper surface of the outer die 18 shown in FIG. That is, while the flange 26 serving as an engagement protrusion on the peripheral edge of each of the mold elements 22 is engaged with the step 27 on the outer mold 18 side, the flange 26 is positioned. It is clamped and fixed by the backup plate 20 arranged.

On the other hand, the extrusion plate 21 is provided with an extrusion pin unit 29 having a large number of extrusion pins 28, 28,... Inserted into the respective guide holes 24 on the upper die body 17 side. Each of the push-out pin units 29 has a plurality of comb-shaped pin segments as shown in FIGS. 11 and 12 for each of the push-out pins 28, 28. ., And each pin piece 30 is divided in the same manner as the upper die body 17 described above.
Are overlapped to form an extrusion pin unit 29. Then, the plurality of pin pieces 30, 30
The push-out pin unit 29 consisting of.
The push-out pin unit 29 is positioned and fixed to the push-out plate 21 by inserting the upper plate 33 into the accommodation hole 32 of the lower plate 31 and then fastening the upper plate 33 to the lower plate 31.

The pushing plate 21 is guided and supported by guide pins 34 fixed to the backup plate 20, and a compression coil spring 3 provided between the pushing plate 21 and the spacer plate 35.
6 is always urged downward. Further, the push-out plate 21 is provided with a return pin 37 which comes into contact with the lower mold body 15, and the push-out plate 21 pushed up by the return pin 37 is separated from the backup plate 20 by a predetermined amount G in the mold clamping state shown in FIG. Only emerging. When the mold is opened, push plate 2
1 is lowered by a predetermined amount G so that each push pin 28
Are pressed down to prevent the product from adhering to the upper mold 12 side.

Therefore, according to the structure of the pressure casting apparatus described above, in the mold clamping state shown in FIG. 7, the cavity formed by the product space 14 on the lower mold 13 side and the product space 16 on the upper mold 12 side is formed. On the other hand, the molten metal is introduced from a runner (not shown) and pressurized by a plunger or the like, so that the radiator 1 as a product is cast.

When the mold is opened from the state shown in FIG.
As described above, the heat radiating pins 3, 3... Are pushed out by the respective pushing pins 28, and the heat radiating board 1 is left on the lower mold 13 away from the upper mold 12 side. Thereafter, the heat sink 1 is protruded using an unillustrated extrusion pin on the lower mold 13 side, and the lower mold 1 is pushed out.
Remove from 3.

As described above, according to the present embodiment, since the heat sink 1 made of aluminum is formed by the molten metal forging method, the pressure in the mold is lower than that of the conventional method of manufacturing the heat sink by the cold forging method. Is reduced to about one-fifth,
This greatly extends the life of the mold.

In addition, the upper mold body 17 includes a plurality of mold elements 2.
, And the extrusion pin unit 29 is also divided into a plurality of pin pieces 30, 30,..., The product part corresponding to each heat radiation pin 3, 3,. Processing of space and each extrusion pin 28, 28 ...
Processing becomes easy. In particular, the upper mold body 17 is
When disassembled into 2, 22,..., The product space 16 corresponding to the heat radiating pins 3, 3,. As a result, the surface roughness can be increased, so that the occurrence of burrs and the like in the product part space 16 can be prevented, and the adhesion of the product to the upper mold 12 can be prevented. In addition, when the specific mold element 22 or the pin piece 30 is broken, it can be dealt with only by replacing only that part, and the cost of the mold can be reduced.

Here, in order to ensure that the heat radiator 1 as a product is smoothly separated from the upper mold 12 and remains on the lower mold 13 when the mold is opened, for example, as shown in FIG. The taper portions 2a are formed on both side surfaces of the lower die body 15 to form a substantially undercut shape, while the lower die body 13 is formed on the lower die body 15 side.
A slide core 38 for avoiding this undercut shape when the product is taken out of the air cylinder 3 is provided.
9 and the like.

The mold structure shown in FIGS. 7 and 13 has a radiator 1 in which each radiating pin 3, 3... Does not have a fin 4, or a radiator 1 of the type shown in FIGS. The same can be applied to the casting of the heat sink 1.

Also, as shown in FIG. 6, the mold structure shown in FIG. 7 is used for casting a heat sink 1 of a type in which a large number of heat sink pins 3, 3,... Are arranged on a plurality of concentric circles a to d. I do.
In this case, however, as shown in FIGS. 14 and 15, the upper mold body 47 is divided into a plurality of annular mold elements 42a to 42e from a position corresponding to the concentric circles a to d with a vertical surface. The push-out pin unit 49 is also divided into a plurality of annular pin pieces 50a to 50e corresponding to the heat radiation pins 3, 3,... Located on the same circles a to d.

[0032]

As described above, according to the structure of the heat radiator of the present invention, the heat radiator provided with a large number of heat radiating pins is formed by a pressure casting method such as molten metal forging, which is advantageous in cost. Of course, by making many heat radiation pins protruding on the base plate tapered,
A large heat radiation area can be ensured, and at the same time, a temperature gradient corresponding to a change in cross-sectional area can be provided, thereby improving the heat radiation efficiency. Further, by projecting fins on the outer periphery of the heat radiation pin, the heat radiation efficiency is further improved.

Further, according to the structure of the pressure casting apparatus of the present invention, the upper die body is divided into a plurality of mold elements, and the extrusion pin unit is also divided into a plurality of pin pieces. The processing of the product space corresponding to each heat radiation pin and the processing of each extrusion pin in the mold body become easy.Especially, if the upper mold body is disassembled into each mold element, the product space corresponding to the heat radiation pin will be half-shaped As a result, it is easy to process the product space by polishing, etc., and it is possible to increase the surface roughness, thereby preventing burrs and the like from occurring in the product space. The product can be prevented from adhering to the mold side. In addition, when a specific mold element or a pin piece is broken, it can be dealt with only by replacing only that part, which has the effect of reducing the cost of the mold.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of a heat sink according to the present invention, and FIG.
2 is a perspective view of the same, and FIG. 2B is an enlarged view of a main part of FIG.

FIG. 2 is an explanatory view showing a modified example of FIG.

FIG. 3 is an explanatory view showing a modified example of FIG.

FIG. 4 is an explanatory view showing a modified example of FIG.

FIG. 5 is an explanatory view showing a modified example of FIG.

FIG. 6 is an explanatory plan view showing a modified example of FIG.

FIG. 7 is an explanatory sectional view showing one embodiment of the pressure casting apparatus of the present invention.

FIG. 8 is a front view of the mold element of FIG. 7;

FIG. 9 is a bottom view of FIG. 8;

FIG. 10 is an explanatory view of the upper die main body of FIG. 7;

FIG. 11 is a front view of the pin piece of FIG. 7;

FIG. 12 is a bottom view of FIG. 11;

FIG. 13 is an explanatory view showing a modification of the mold structure of FIG. 7;

FIG. 14 is an essential part perspective view showing another example of the upper mold main body of FIG. 7;

FIG. 15 is an essential part perspective view showing another example of the push-out pin unit of FIG. 7;

FIG. 16 is a perspective view showing an example of a conventional heat sink.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Heat sink 2 ... Base plate 3 ... Heat radiating pin 4, 4A ... Fin 12 ... Upper mold 13 ... Lower mold 12a, 13a ... Mold fitting surface 14 ... Product part space 16 ... Product part space 17 ... Upper mold body 18 ... Outer mold DESCRIPTION OF SYMBOLS 20 ... Backup plate 21 ... Extrusion plate 22 ... Mold element 25 ... Housing hole 26 ... Flange part (engagement protrusion part) 27 ... Stepped part 28 ... Extrusion pin 29 ... Extrusion pin unit 30 ... Pin piece 34 ... Guide pin 37 ... Return pin 47 ... Upper die body 42a-42e ... Die element 49 ... Extrusion pin unit 50a-50e ... Pin piece a-e ... Concentric circle

Claims (4)

(57) [Claims] 1. A heat dissipating plate structure formed by a pressure casting method, wherein a large number of heat dissipating pins are erected on an upper surface of a base plate, and each heat dissipating pin has a cross-sectional area from its root to its tip. Is formed in a tapered shape that gradually becomes smaller, and furthermore, one or a plurality of fins are formed so as to protrude from an outer periphery of at least a part of the plurality of heat radiation pins along an axial direction thereof. 2. The heat sink according to claim 1, wherein the plurality of heat sink pins are located on a plurality of concentric circles. 3. An apparatus for casting, by pressure casting, a radiator plate having a large number of tapered radiating pins having a gradually decreasing cross-sectional area from a root portion to a tip portion on an upper surface of a base plate. The upper and lower dies, which perform mold clamping and mold opening operations, with the position corresponding to the upper surface of the base plate on which a large number of radiating pins protrude from the radiator being used as a mold-matching surface. Is formed in the product part space corresponding to the base plate, and the product part space corresponding to the large number of heat radiation pins is formed on the upper mold side, respectively. An upper mold body divided into a plurality of mold elements having engagement projections on a peripheral edge thereof with a vertical plane passing through the centers of the plurality of heat radiation pins to form a product part space corresponding to the large number of heat radiation pins; To the upper mold An accommodating hole for accommodating the body is formed, and a stepped portion that engages with the engaging projection of each of the mold elements is formed on a peripheral edge of the accommodating hole, and is inserted from above the accommodating hole. An outer mold supporting a plurality of mold elements to be mounted; a backup plate mounted on an upper surface of the outer mold to restrain an upper mold body composed of the plurality of mold elements; and an upper mold disposed above the backup plate, An extrusion pin unit having a large number of extrusion pins inserted into positions corresponding to the heat radiation pins in a product portion space of the main body, wherein the extrusion pin units are formed by a plurality of heat radiation pins formed by a pair of adjacent mold elements. Extrusion that is divided into a plurality of comb-shaped pin pieces corresponding to the above, and that moves up and down in accordance with the mold clamping and mold opening operations to project each heat radiation pin from the upper mold body when the mold is opened. Plate, to be composed of capital radiating board of pressure casting apparatus according to claim. 4. The pressure casting apparatus for a radiator plate according to claim 3, wherein the plurality of radiating pins are set to be located on a plurality of concentric circles, while the upper mold body has a plurality of mold elements having the concentric circles. Wherein the extrusion pin unit is divided into a plurality of pin pieces for each of a plurality of heat radiation pins on each concentric circle.