JPH07161889A - Heat sink fan - Google Patents

Abstract

PURPOSE:To provide a thin heat sink fan by blowing air in the direction perpendicularly to the rotation axis with a rotating cross-flow fan, to the fin and radiation pins so as to improve the radiation characteristics. CONSTITUTION:A cross-flow fan 25 is contained near the one of the two side 22a, 22b inside a heat sink 22, the both ends of the rotation axis 26 is rotatably supported by means of a bearing 27, 28 at a position of other two sides 22c, 22d of the heat sink 22. Moreover, a plurality of radiation pins 24 are provided on the bottom surface of the inside of the heat sink 22 excepting, at least, the contained position of the cross-flow fin 25. Wind is generated in the direction perpendicularly to the rotation axis 26 by the rotation of the cross-flow fan 15 to blow air to the fin 23a-23d and the radiation pins 24. Thus, the heat sink 22 is rapidly cooled to suppress the temperature rise of the heating element contacting with the lower surface of it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat sink fan having a small fan motor.

[0002]

2. Description of the Related Art A small fan motor is generally and widely used for various purposes such as office automation equipment, medical equipment, research and experiment equipment, and equipment for preventing heat generation of equipment containing many electronic components, and other purposes. ing.

6 and 7 show a heat sink fan as an example of a device for preventing heat generation using a small fan motor. In these figures, the fan motor 1
Is a casing 2 having a rectangular planar shape, a box-shaped heat sink 3 having a rectangular planar shape with an open upper surface, a propeller-shaped impeller 4 supported by the casing 2 and housed in the heat sink 3, and the like. And a drive portion including a. Casing 2
The heat sink 3 and the heat sink 3 form a space in which the driving portion rotates inside.

The casing 2 has a plurality of openings 5 through which air can freely flow around the upper surface thereof, and a connecting portion 7 having blind holes 6 (see FIG. 7) opened on the lower surface at each of four corners is integrally formed. It is provided. On the other hand, the heat sink 3 has four side heat sink fins 9 rising from the periphery of the heat sink bottom 8 having a blind bottom as shown, a circular punching window (not shown) or the like, and casings at the four corners. A connecting portion 11 having a protruding portion 10 that can be received in the blind hole 6 of 2;
have. The casing 2 is fixed to the heat sink 3 by press-fitting the protrusion 10 into the blind hole 6.

The impeller 4 has a bowl-shaped rotating member 12 and a plurality of blades 13 projecting from the outer peripheral portion of the bowl-shaped rotating member 12.
One end of the rotary shaft 14 is fitted into a through hole provided at the center of the bowl-shaped rotary member 12,
Is rotatably supported by a bearing 15 inside a cylindrical portion provided at the center of the casing 2. A rotor magnet 16 is provided on the inner peripheral surface of the bowl-shaped rotating member 12 via a yoke.
Is attached, and the bowl-shaped rotating member 12, the yoke, and the rotor magnet 16 form a rotor 17.

Further, on the outer periphery of the cylindrical portion provided at the center of the casing 2, there are provided a stator core having a plurality of teeth arranged along the circumferential direction, and a coil wound around the teeth of the stator core. The stator 18 composed of is externally fitted. When using, the heat sink bottom portion 8 of the heat sink 3 constituting the fan motor 1 is
The heat generating component 20 such as an LSI disposed on the circuit board 19 is placed in contact with the heat generating component 20.

When the fan motor 1 is rotated via the lead wire 21, the impeller 4 of the driving portion is rotated and passes through the opening 5 of the casing 2 in the axial direction, for example, from the heat sink fin portion 9 through the inside of the heat sink 3. An air flow path is formed. In this way, the heat generated from the heat generating component 20 and the like is sufficiently dissipated, which contributes to the prevention of thermal destruction of the component and the like.

Also, since air flows from the heat sink fin portion 9 of the heat sink 3 to the opening 5 of the casing 2,
The dust is blocked off on the outside of the heat sink fin portion 9, can be prevented from entering the inside of the heat sink 3, and the dust attached on the outside of the fan motor 1 can be easily removed.

[0009]

However, in the above-mentioned conventional heat sink fan, the heat sink 3 is provided with an axial fan whose thickness direction is the axial direction, and therefore it is difficult to reduce the thickness. is there. That is, in the axial fan, the pair of ball bearings 15 becomes a neck against the axial thinning, and if the thickness of the ball bearings 15 is reduced, the reliability of rotation is deteriorated. Therefore, the thickness cannot be reduced so much. As a result, it is difficult to reduce the thickness.

Further, the conventional heat sink fan has a drawback that the amount of air blown by the rotation of the fan is not so large because the air intake direction and the air exhaust direction intersect.

Moreover, this type of heat sink fan is mounted on an LSI mounted on a circuit board and blows air in a direction perpendicular to the board surface. Since they are provided and arranged in parallel, there is a problem that the adjacent circuit board becomes a resistance against the air discharged from the axial fan, and as a result, the expected air flow cannot be obtained and the heat dissipation characteristic is deteriorated.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide a heat sink fan which has good heat dissipation characteristics and can be thinned. Especially.

[0013]

In order to achieve the above object, a heat sink fan of the present invention is a box in which an upper surface is open, a lower surface is in contact with a heating element, and fins are formed on at least two opposing side walls. A mold-shaped heat sink for heat radiation, and both ends of the rotating shaft housed near one of the two sides inside the heat sink are rotatably mounted on two other sides of the heat sink via bearings other than the two sides. A supported cross-flow fan, a lid part attached to the opening edge of the heat sink in a lid-like manner, and a plurality of heat-dissipating pins provided on the bottom surface of the heat sink except at least the accommodating position of the cross-flow fan. It is characterized in that wind is generated in a direction orthogonal to the rotation axis by the rotation of the crossflow fan and is blown to the fins and the heat dissipation pins.

In this case, it is desirable to form fins on the other two sides of the heat sink, leaving the bearing mounting portion.

Further, it is preferable to form a concave surface that also serves as a casing of the crossflow fan on the bottom surface of the heat sink at the crossflow fan accommodation position and the top surface of the lid portion at the crossflow fan accommodation position.

Alternatively, the lid portion may be provided with supporting pieces that respectively constitute a part of the other two sides of the heat sink, and the rotating shaft of the crossflow fan may be rotatably supported by bearings on the supporting pieces. Is also preferable.

In this case, a circuit board to which the armature winding of the motor section is connected is provided in the motor section provided at the end of the crossflow fan, and the circuit board led out from the motor section is provided on the lower surface of the lid section. Good to wear.

In particular, it is preferable that the circuit board is extended to the air blowing position of the cross flow fan along the lower surface of the lid, and the extended circuit portion is mounted with a circuit component that requires heat radiation.

[0019]

In the heat sink fan of the present invention configured as described above, when the cross flow fan is driven,
Wind is generated in a direction orthogonal to the rotation axis of the cross flow fan, and air mainly flows in a direction passing through two opposing sides where the fins of the heat sink are formed.

This cross-flow fan can provide a larger amount of air than an axial-flow fan, and a large amount of air can be provided on the bottom surface of the fins on the two sides and the heat sink except the cross-flow fan accommodating position. The heat sink is quickly cooled by the air blown to the heat radiating pins, and suppresses the temperature rise of the heating element in contact with the lower surface of the heat sink.

When the heating element is an LSI or the like, the temperature of the heating element rises most at the central portion thereof, but since the radiation pins are also arranged at the central portion of the heat sink, the heating element can be effectively cooled.

Further, since the blowing direction of the cross flow fan is parallel to the bottom surface of the heat sink, that is, the surface of the heating element, in the case of an LSI or the like in which the heating element is mounted on the circuit board, a plurality of circuit boards are used in the computer system. Although they are arranged in parallel with a required gap, the airflow direction of the cross flow fan is parallel to the circuit board, and the circuit board does not become a resistance to the air flow, and the heat dissipation characteristics are further improved. .

[0023]

Embodiments of the present invention will be described with reference to FIGS. 1 to 3 show a first embodiment, which is applied to a case where a heat-generating component such as an LSI mounted on a circuit board is cooled, as described in the prior art.

The heat sink 22 which is thermally conductively joined to the upper surface of a heat-generating component such as an LSI is formed in a box-shaped square shape having an open upper surface, and is made of a material having excellent heat conductivity such as aluminum die cast. There is.

In this heat sink 22, a large number of fins 23a and 23b are formed by forming vertical grooves on the two sides 22a and 22b facing left and right, and the other two sides 22c facing front and back are formed. A large number of fins 23c and 23d are formed by forming a longitudinal groove in the front-rear direction while leaving the right side portion of 22d.

Further, on the inner bottom surface of the heat sink 22,
A plurality of heat dissipation pins 24 are provided in the entire area except the right side portion, which is a housing position of a cross flow fan described later.

The other two sides 22c, 22 of the heat sink 22
On the right side of d, a rotation shaft 26 in the front-rear direction of the crossflow fan 25 is rotatably supported via bearings 27 and 28.

The cross-flow fan 25 comprises a motor section 29 and an impeller 30 integrally formed with the motor section 29 and having a large number of front and rear blades arranged in the circumferential direction.
A bracket 31 that supports the motor unit 29 is fixed to the front side 22c of the heat sink 22.

Motor part 29 of the cross flow fan 25
As shown in FIG. 3, the rotary shaft 26 is inserted into the cylindrical portion 32 of the bracket 31, the cup-shaped rotor 33 is fixed to the rotary shaft 26, and the stator 34 fixed to the outer circumference of the cylindrical portion 32 is attached to the stator 34. A rotor magnet 35 is fixed to the inner surface of the peripheral wall of the rotor 33 so as to face each other.
When the coil of the stator 34 is excited, the stator 3
The electromagnetic interaction between the rotor magnet 35 and the rotor magnet 35 causes the rotor 33 to rotate together with the rotor magnet 35, and the impeller 30 to rotate.

The upper surface opening of the heat sink 22 is the lid portion 3.
It is covered by 6. As shown in FIG. 2, curved surfaces 37 and 38 forming a casing of the crossflow fan 25 are formed at the crossflow fan accommodation positions of the inner bottom surface of the heat sink 22 and the lid portion 36, respectively.

In the heat sink fan having such a structure, when the cross flow fan 25 is driven, air is generated by the rotation of the impeller 30, and the external air of the heat sink 22 passes through between the fins 23a of the left side 22a to the inside. And is introduced into the inside through the fins 23c and 23d of the front and rear sides 22c and 22d, respectively, and these are discharged to the outside through the fins 23b of the right side 22b.

When the air passing through the inside and outside of the heat sink 22 comes into contact with the fins 23a, 23b, 23c, 23d and the heat radiating pins 24, the heat sink 22 is cooled and heat dissipation of heat-generating components such as LSI is promoted. Here, the cross-flow fan 25 has a small static pressure but a very large amount of air blow, and since the air flow is parallel to the plane of the heat sink 22, it is the same as when an axial fan is used as in the conventional case. No large resistance is generated, heat exchange in the heat sink 22 is promoted, and heat dissipation characteristics are improved.

Particularly in the case of an LSI, the central part of the package generates the most heat, but the heat sink 22 of the embodiment has the heat dissipating pins 24 in almost the entire area including the central part, so that effective heat dissipation can be realized. It is a thing.

The rotary shaft 2 of the cross flow fan 25
6 is rotatably supported by the front and rear sides 22c and 22d of the heat sink 22, but in this case, the bearings 27 and 28 are the front and rear sides 22.
It may be selected according to the heights and thicknesses of c and 22d, and there is almost no restriction on the thickness of the heat sink fan. Therefore, the bearings 27 and 28 can be made large to some extent, and the crossflow fan 25 Stable support is possible.

Next, a second embodiment of the present invention will be described with reference to FIGS. The same reference numerals as those used above denote the same or corresponding ones.

The heat sink 2 is shown in this embodiment.
2, the right side portions of the front and rear sides 22c and 22d, that is, the notch portion 39 upward to the accommodation position corresponding to the cross flow fan 25,
40, and support pieces 41 and 42 that fit therein are integrally provided on the front and rear side edges of the lid 36, and the support piece 4 is formed.
The rotary shaft 26 of the cross flow fan 25 is rotatably supported by the bearings 1 and 42 via bearings 27 and 28.

Further, the bracket 31 in the motor portion 29 of the cross flow fan 25 is fixed to the support piece 41,
The flexible circuit board 43 attached to the bracket 31 is extended along the lower surface of the lid portion 36 to the upstream side of the impeller 30 in the air blowing direction, and the extended portion generates heat to generate electronic components 4.
4 is implemented.

According to the second embodiment, since the crossflow fan 25 can be integrally supported by the lid 36 via the support pieces 41 and 42, the crossflow fan 25 can be simply attached to and detached from the heat sink 22. Can be repaired or replaced, and the cross flow fan 25 can be easily maintained.

In addition, the circuit board 43 of the cross flow fan 25 integrated with the lid portion 36 extends into the air blowing space inside the heat sink 22 so that the electronic components 44 on the circuit board 43 are exposed in this air blowing space. Therefore, the heat release of the electronic component 44 can be promoted, and the electrical characteristics can be improved.

Although the embodiments of the heat sink fan according to the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and corrections can be made without departing from the scope of the present invention. . For example, the flexible circuit board 43 of the second embodiment is not limited to this, and may be a circuit board using a normal phenol board or a three-dimensionally molded three-dimensional circuit board.

[0041]

Since the present invention is constructed as described above, it has the following effects. A cross flow fan with a large air flow is provided near one side inside the heat sink, and air is introduced into the heat sink through the fins on the opposite side, and is discharged to the outside through the fins on one side. A small and smooth heat exchange is realized.

Moreover, since a plurality of heat dissipation pins are provided in the entire area of the bottom surface of the heat sink except for the cross flow fan accommodating position, almost the entire area including the central portion of the heat sink can be quickly cooled, and the effect of cooling the heating element is improved. It will be.

Particularly, the LS in which the heating element is mounted on the circuit board.
In the case of I or the like, a plurality of circuit boards of this kind are arranged in parallel in a computer system with a required gap provided. However, as described above, the air flow direction by the cross flow fan is parallel to the heat sink, so the circuit board Does not become a resistance to air flow, and the heat dissipation effect is significantly improved.

Further, since the rotary shaft of the cross-flow fan is rotatably supported by the other two sides of the heat sink, the bearing may be selected according to the height and thickness of this side, and the thickness of the heat sink fan is not restricted. There are few, and therefore, the bearing can be made large, and stable support of the cross flow fan is possible.

[Brief description of drawings]

FIG. 1 is a plan view of a heat sink showing a first embodiment of a heat sink fan of the present invention.

FIG. 2 is a cutaway front view of the heat sink fan of FIG.

FIG. 3 is a cutaway side view of the heat sink fan of FIG.

FIG. 4 is a cut side view showing a second embodiment of the heat sink fan of the present invention.

5 is a cutaway side view of the heat sink fan of FIG.

FIG. 6 is an exploded perspective view of a conventional heat sink fan.

FIG. 7 is a cross-sectional view of a conventional heat sink fan.

[Explanation of symbols]

 22 heat sinks 22a, 22b, 22c, 22d sides 23a, 23b, 23c, 23d fins 24 radiating pins 25 cross flow fans 26 rotating shafts 27, 28 bearings 36 lids 41, 42 support pieces 43 flexible circuit boards 44 electronic components

Claims (6)

[Claims] 1. A box-shaped heat sink for heat radiation, the upper surface of which is open, the lower surface of which is in contact with a heating element, and fins are formed on at least two opposite side walls of the heat sink. Both ends of the rotary shaft that are accommodated on one side are located at the two sides of the heat sink.
A cross flow fan rotatably supported at two other positions other than the sides via bearings, a lid part attached to the opening edge of the heat sink in a lid-like manner, and at least the inside of the heat sink. A plurality of heat radiating pins provided on the bottom surface excluding the accommodating position of the cross flow fan, and a wind is generated in a direction orthogonal to the rotation axis by the rotation of the cross flow fan to blow air to the fins and the heat radiating pins. A heat sink fan characterized by being 2. The other two sides of the heat sink include:
The heat sink fan according to claim 1, wherein the fin is formed leaving the mounting portion of the bearing. 3. A concave surface that also serves as a casing of the crossflow fan is formed on a bottom surface of the heat sink at the crossflow fan accommodation position and an upper surface of the lid portion at the crossflow fan accommodation position. Heatsink fan as described. 4. The cover portion is provided with support pieces that respectively configure a part of the other two sides of the heat sink,
The heat sink fan according to claim 1, wherein a rotary shaft of the cross flow fan is rotatably supported by the support pieces via the bearings. 5. The motor section provided at the end of the cross-flow fan is provided with a circuit board to which an armature winding of the motor section is connected, and the circuit board led out from the motor section is It is attached to the lower surface of the lid portion.
Heatsink fan as described. 6. The circuit board according to claim 5, wherein the circuit board is extended to a blowing position of the cross flow fan along a lower surface of the lid, and a circuit component requiring heat radiation is mounted on the extended portion. Heatsink fan.