JP3833676B2 - heatsink - Google Patents

Description

  The present invention relates generally to a heat sink having means for performing forced air cooling, and more particularly to a heat sink applied to at least two heating elements including first and second integrated circuit packages mounted on a printed wiring board. About.

  2. Description of the Related Art In recent years, portable electronic devices typified by laptop computers, for example, are widely on the market as electronic devices that are required to be downsized and highly reliable. In order to improve the performance of this type of electronic device, it is necessary to use one or more integrated circuit packages that generate a large amount of heat. For this reason, a heat sink is used when mounting the integrated circuit package on a printed wiring board in order to ensure heat dissipation of the integrated circuit package having a large amount of heat generation.

  Conventionally, a heat sink with a built-in fan has been put to practical use as a heat sink having means for performing forced air cooling. When applying a heat sink with a built-in fan to an electronic apparatus having a plurality of heat generating elements, one heat sink with a built-in fan is fixed to each heat generating element. For this reason, the use of a plurality of heat sinks with built-in fans has caused problems such as reduced reliability, increased noise, increased power consumption, and increased costs. Further, when the heating element is small, there is a problem that the heat radiation area of the heat sink becomes insufficient, and it becomes difficult to cope with the high heating element.

  Accordingly, an object of the present invention is to provide a heat sink suitable for use with a plurality of heating elements.

According to the present invention, there is provided a heat sink applied to at least two heating elements including a first heating element mounted on a printed wiring board and a second heating element spaced from the first heating element. And the lower surface is fixed to the first and second heating elements, and is between the first and second heating elements on the upper surface and overlaps the first and second heating elements. A base member having a plurality of heat-dissipating fins protruding from the upper surface at a portion excluding the air blowing region on the upper surface, and a fin member disposed on the upper surface; There is provided a heat sink including air cooling means for circulating air through the air.

  In the present invention, the air blowing area in which the air cooling means is located is provided approximately in the middle of the first and second heating elements, so that both the first and second heating elements are forcibly used by using one air cooling means. This is because, for example, the bearing temperature of the air-cooling means composed of a fan assembly is prevented from increasing, and the reliability is improved.

  In the present invention, since one air cooling means is used for a plurality of heating elements, noise and power consumption can be reduced. Further, when the first and second heating elements are provided apart from each other, the heat dissipation area of the heat sink can be increased, and the cooling performance is improved.

  According to the present invention, it is possible to provide a heat sink suitable for use with a plurality of heating elements.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  1 is a perspective view of a heat sink showing a first embodiment of the present invention, FIG. 2 is a perspective view showing a state where a cover of the heat sink of FIG. 1 is removed, and FIG. 3 is a cross-sectional view of the heat sink of FIG. . This heat sink is applied to at least two heating elements including the integrated circuit packages 4 and 6 mounted on the printed wiring board 2. In the following description, it is assumed that the heating elements are only the integrated circuit packages 4 and 6, but the heat sink of the present invention can also be applied when other heating elements are mounted on the printed wiring board 2.

  The base member 8 is fixed so that its lower surface BS is in close contact with the upper surfaces of the integrated circuit packages 4 and 6. The base member 8 may be fixed to the integrated circuit packages 4 and 6 by adhesion, but may be fixed using a belt or clipper made of resin.

  An air blowing area 10 is secured in the middle of the integrated circuit packages 4 and 6 on the upper surface US of the base member 8 as shown in FIG. The base member 8 has a plurality of heat dissipating fins 12 that protrude from the upper surface US except for the air blowing region 10.

  A fan assembly 14 is attached to the fin 12 in order to allow air to flow between the air blowing region 10 and the outside via the fin 12. In this embodiment, the fan assembly 14 is secured by four screws 16.

  In the positional relationship between the fan assembly 14 and the base member, a certain clearance is provided between the bottom of the fan assembly 14 and the upper surface US of the base member 8 as shown in FIG. As described above, the fan assembly 14 is not directly adhered to the upper surface US of the base member 8. That is, the fan assembly 14 is arranged in a state of floating from the upper surface US of the base member 8.

  Reference numeral 18 denotes a hole formed in the base member 8 so as to penetrate from the upper surface to the lower surface. When the integrated circuit package has an anchor bolt (not shown) at the center of the upper surface, the anchor 18 is provided. Bolts are made to pass through the holes 18, thereby ensuring adhesion between the base member 8 and the integrated circuit packages 4 and 6. If the integrated circuit packages 4 and 6 do not have anchor bolts, the base member holes 18 are not required.

  FIG. 3 is a cross-sectional view taken along the line AA in FIG. 1, and shows a detailed configuration of the fan assembly 14 as air cooling means. The fan assembly 14 includes a cover 20 that is fixed to the fin 12 so as to cover the air blowing area 10, a motor 24 that is fixed to the cover 20 and has a spindle 22 in the thickness direction of the base member 8, and a blade 26 that is rotated by the motor 24. And a printed wiring board 28 having a drive circuit for driving the motor 24.

  The cover 20 has an annular protrusion 30 on its lower surface, and the motor 24 is fixed to the protrusion 30.

  The motor 24 is press-fitted / fixed to the annular projection 30 and has a stator 34 having a coil 32 on the outer periphery, a bearing 36 that rotatably supports the spindle 22 with respect to the stator 34, and a fixed to the spindle 22 on the inner peripheral wall. The magnet 38 further includes a rotor 40 to which the blade 26 is fixed on the outer peripheral wall.

  Reference numeral 41 is a lead wire for connecting the drive circuit to the outside, reference numeral 42 is a ring yoke, reference numeral 44 is a yoke, reference numeral 46 is a cut washer attached to the spindle 22, and reference numeral 48 is for biasing the spindle 22 upward. The spring is shown. Reference numeral 50 represents an air circulation opening provided in the cover 20, and reference numeral 52 represents an annular projection for securing a static pressure difference. A plurality of openings 50 are provided along the rotation locus of the blade 26.

  In this embodiment, external air is taken into the blower area 10 through the opening 50, and the taken-in air is blown to the fins 12. Thereby, forced air cooling is performed. The rotation direction of the motor 24 or the inclination angle of the blade 26 may be changed so that the direction of airflow is reversed.

  According to this embodiment, forced air cooling can be performed with respect to at least two heating elements by one fan assembly, so that it is possible to improve reliability, reduce noise, and reduce power consumption. Further, since the integrated circuit packages 4 and 6 are provided apart from each other, the heat radiation area of the base member 8 is increased accordingly, and the cooling performance of the heat sink is improved.

  In this embodiment, since the fan assembly 14 is not located immediately above the integrated circuit packages 4 and 6, the temperature of the motor 24 does not rise so much and high reliability can be ensured.

  FIG. 4 is a perspective view of a heat sink showing a second embodiment of the present invention. In this embodiment, the heat sink of FIG. 1 is applied to relatively large integrated circuit packages 4 'and 6'.

  If the integrated circuit packages 4 ′ and 6 ′ are relatively large, the gap between them may be smaller than the width of the fan assembly 14. Even in such a case, good cooling characteristics can be obtained by positioning the fan assembly 14 approximately in the middle of the integrated circuit packages 4 'and 6'. Desirably, the central portion of the fan assembly 14 is positioned at a substantially midpoint on a straight line connecting the heat generation center of the integrated circuit package 4 'and the heat generation center of the integrated circuit package 6'.

  As the material of the base member 8 in the first and second embodiments, for example, aluminum having good heat dissipation and workability can be adopted.

  FIG. 5 is a perspective view of a heat sink showing a third embodiment of the present invention. This heat sink is characterized in that the base member 8 has a two-layer structure of a first member 54 that is in close contact with the integrated circuit packages 4 and 6 and a second member 56 that integrally has the fins 12.

  Desirably, these materials are selected such that the thermal conductivity of the first member 54 is greater than the thermal conductivity of the second member 56. As a result, heat from the integrated circuit packages 4 and 6 is easily transferred to each of the fins 12, soaking the base member 8 is promoted, and the cooling performance is significantly improved.

  For example, copper or copper tungsten can be used as the material of the first member 54, and aluminum can be used as the material of the second member 56. When the material of the first member 54 is copper tungsten, its linear thermal expansion coefficient is substantially equal to the linear thermal expansion coefficient of a typical ceramic as a material of the integrated circuit package, so that the adhesion between the base member and the integrated circuit package is increased. It can be kept good over the period.

  FIG. 6 is a perspective view of a heat sink showing a fourth embodiment of the present invention. This embodiment is characterized by a joining technique between a first member 54 made of copper or copper tungsten and a second member 56 made of aluminum.

  The second member 56 has a nickel plating layer (not shown) on at least its lower surface, and the first member 54 and the second member 56 are brazed and joined by a solder layer 58 interposed therebetween.

  When the 1st member 54 and the 2nd member 56 are joined by brazing, since the heat transfer loss in a joined surface becomes small, cooling performance improves. In addition, when the relatively thin first member 54 is warped by brazing, the lowering of the cooling performance can be prevented by flattening the lower surface of the first member 54 by, for example, polishing after brazing. it can.

  In order to increase the bonding area of the first member 54 and the second member 56, irregularities that engage with each other may be formed. Examples of such irregularities are shown in FIGS. 7A, 7B, and 7C as a fifth embodiment.

  The cross-sectional shapes of the concave and convex portions of the joint are a triangle, a rectangle and a trapezoid in (A), (B) and (C), respectively. By forming such irregularities, the thermal conductivity between the first member 54 and the second member 56 is improved, so that the cooling performance of the heat sink is improved.

  FIG. 8 is a perspective view of a heat sink showing a sixth embodiment of the present invention, and FIG. 9 is a sectional view taken along line BB in FIG. In this embodiment, in contrast to the third embodiment of FIG. 5, the first member 54 has an edge portion 54A that protrudes outside the second member 56, and an auxiliary fin 60 that is integral with the edge portion 54A. It is characterized in that

  The fins 12 that the second member 56 has integrally are regularly aligned at equal pitches in the vertical and horizontal directions, and the auxiliary fins 60 are also regularly aligned at the same pitch as the pitch of the fins 12.

  In this embodiment, auxiliary fins 60 are provided on both sides of the base member 8 in the longitudinal direction. In addition to this, auxiliary fins are provided at both longitudinal ends of the base member 8 as indicated by broken lines 60 '. Further, it may be provided.

  According to this embodiment, since the cooling effect of the first member 54 is increased, the cooling performance of the heat sink is improved.

  FIG. 10 is a perspective view of a heat sink showing a seventh embodiment of the present invention. This embodiment is characterized in that the thickness of the portion 54A corresponding to the integrated circuit packages 4 and 6 in the first member 54 is larger than the thickness of the portion 54B in close contact with the integrated circuit packages 4 and 6. .

  According to this embodiment, since the thermal conductivity of the first member 54 can be improved, the cooling performance of the heat sink can be improved. Further, by forming a depression on the upper surface of the thick portion 54A of the first member 54 and accommodating a part of the motor of the fan assembly 14 in the inside thereof, the heat sink can be made thin.

  FIG. 11 is a sectional view of a heat sink showing an eighth embodiment of the present invention. The cross-sectional position is the same as the cross-sectional position of FIG. 3 in the first embodiment.

  This embodiment is characterized in that the base member 8 has a ventilation hole 62 penetrating from the upper surface to the lower surface. The hole 62 is formed between the integrated circuit packages 4 and 6 in the blowing area. Particularly in this embodiment, a plurality of holes 62 are provided along the rotation trajectory of the blade 26 of the fan assembly 14.

  The presence of such holes 62 allows high-speed wind to pass therethrough, so that the heat sink cooling performance can be improved.

  FIG. 12 is a perspective view of a heat sink showing a ninth embodiment of the present invention. The fins 12 are regularly arranged in the vertical direction (arrow 64) and the horizontal direction (arrow 66) on the upper surface of the base member 8. Particularly in this embodiment, the pitch of the fins in the vertical direction is made larger than the pitch of the fins in the horizontal direction.

  By adopting such an arrangement of fins, when the heat sink is used in an environment where an air flow occurs, the air flow can be effectively used to cool the heating element.

  For example, when this heat sink is applied to a device in which an air flow is generated inside by a system fan or the like, the horizontal direction (arrow 66) where the pitch of the fins is small substantially coincides with the direction of the air flow in the device. Like that. In this way, the air flow in the device that is normally weaker than the air flow generated by the fan assembly 14 will flow in the direction of arrow 66, and the air flow generated by the fan assembly 14 will flow mainly in the direction of arrow 64, thereby reducing the air flow in the device. It can be used effectively. Thereby, the cooling performance of the heat sink is improved.

  FIG. 13 is a perspective view of a heat sink showing a tenth embodiment of the present invention. This embodiment is characterized in that the fan assembly 14 has a large cover 20 ′ that covers substantially all of the fins 12.

  According to this embodiment, the air circulation speed of the fan assembly 14 through the fins 12 can be increased, so that the cooling performance of the heat sink is improved.

  FIG. 14 is a perspective view of a heat sink showing an eleventh embodiment of the present invention. In this embodiment, as in the first embodiment of FIG. 1, the cover 20 of the fan assembly 14 covers some of the fins close to the air blowing area.

  And the base member 8 is produced so that the fin 12 'covered with the cover 20 is shorter than the other fins. According to this embodiment, since the fan assembly 14 does not protrude beyond the tip of the longer fin 12 in the base member 8, the heat sink can be made thin. Therefore, this embodiment is suitable for combination with the seventh embodiment of FIG.

  In the embodiments described above, the heating elements are only the integrated circuit packages 4 and 6. However, the present invention can also be applied to the case where there are other heating elements on the printed wiring board 2 or other positions. . In this case, the shape of the base member is set according to the position and shape of the other heating element, and the base member is in contact with the heating element.

It is a perspective view of the heat sink which shows 1st Example of this invention. It is the perspective view which took the cover of the heat sink of FIG. It is AA sectional drawing in FIG. It is a perspective view of the heat sink which shows 2nd Example of this invention. It is a perspective view of the heat sink which shows 3rd Example of this invention. It is a perspective view of the heat sink which shows 4th Example of this invention. It is sectional drawing of the heat sink which shows 5th Example of this invention. It is a perspective view of the heat sink which shows 6th Example of this invention. It is BB sectional drawing in FIG. It is a perspective view of the heat sink which shows 7th Example of this invention. It is sectional drawing of the heat sink which shows 8th Example of this invention. It is a perspective view of the heat sink which shows 9th Example of this invention. It is a perspective view of the heat sink which shows 10th Example of this invention. It is a perspective view of the heat sink which shows 11th Example of this invention.

Explanation of symbols

2 Printed wiring board 4, 6 Integrated circuit package 8 Base member 10 Air blowing area 12 Fin 14 Fan assembly 20 Cover

Claims (14)

A heat sink applied to at least two heating elements including a first heating element mounted on a printed wiring board and a second heating element spaced from the first heating element ,
A lower surface and an upper surface, the lower surface being fixed to the first and second heating elements, and between the first and second heating elements on the upper surface and to the first and second heating elements. A base member having a plurality of heat-dissipating fins protruding from the upper surface in a portion excluding the air blowing region on the upper surface, the air blowing region in a position not overlapping.
A heat sink provided with an air cooling means provided in the air blowing area and for circulating air through the fins. The air cooling means is
A cover fixed to the fin so as to cover the blowing area;
A motor fixed to the cover and having a spindle in the thickness direction of the base member;
A blade rotated by the motor;
The heat sink according to claim 1, comprising a drive circuit for driving the motor.   The heat sink according to claim 2, wherein the cover further covers substantially all of the plurality of fins.   2. The heat sink according to claim 1, wherein the base member has a multilayer structure including a first member to which the first and second heating elements are fixed and a second member integrally having the fin.   The heat sink according to claim 4, wherein the thermal conductivity of the first member is larger than the thermal conductivity of the second member.   The heat sink according to claim 5, wherein a material of the first member is selected from copper and copper tungsten, and a material of the second member is aluminum.   The heat sink according to claim 6, wherein the second member has a nickel plating layer on at least a lower surface thereof, and the first member and the second member are joined by soldering.   The heat sink according to claim 4, wherein the first member and the second member have concave and convex portions that mesh with each other for increasing a bonding area.   5. The heat sink according to claim 4, wherein the first member includes an edge protruding outside the second member and an auxiliary fin integrated with the edge.   2. The heat sink according to claim 1, wherein the base member has a ventilation hole penetrating from the upper surface to the lower surface between the first and second heating elements in the air blowing region.   The thickness of the part corresponding to the position which does not overlap between the said 1st and 2nd heat generating body in the said 1st member is larger than the thickness of the part closely_contact | adhered to the said 1st and 2nd heat generating body. heatsink.   The heat sink according to claim 1, wherein the fins are regularly aligned in a vertical direction and a horizontal direction on an upper surface of the base member, and a pitch of the fins in the vertical direction is different from a pitch of the fins in the horizontal direction. A heat sink according to claim 12, applied to a device adapted to generate an air flow therein.
A heat sink that is set so that a direction in which the pitch of the fins is small in the vertical direction and the horizontal direction substantially coincides with the direction of the air flow. The cover further covers a part of the plurality of fins near the air blowing area,
The heat sink according to claim 2, wherein a length of the fin covered by the cover is smaller than a length of the fin not covered by the cover.

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