JP3143811B2 - Heat pipe type heat sink - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an evaporator,
A heat pipe type heat sink comprising a plurality of flat heat pipes the other of which is a condensing section, a heating element attached to the evaporating section, and heat generated from the heating element being released from the condensing section. It is about.

[0002]

2. Description of the Related Art Electronic components used in electronic equipment, power equipment, and the like, particularly semiconductor elements, generate heat during operation and need to be appropriately cooled. A cooling device for cooling such a heating element generally includes a mounting portion to which the heating element is mounted, and a heat radiation fin integrally provided on the mounting portion. Therefore, heat generated from a heating element such as a semiconductor element is transmitted from the mounting portion to the fin by conduction, and is released from the fin to the atmosphere mainly by radiation. By the way, semiconductor elements as heat generating elements tend to be highly integrated and have large capacities, and the amount of heat generated has increased accordingly. Therefore, cooling by the above-described heat conduction cannot be sufficiently performed. Therefore, a heat pipe type heat sink has been proposed. Heat pipes can be roughly classified into a siphon type and a wick type, and each type of heat pipe has a feature that its structure is simple. Particularly, the siphon type heat pipe has a simple structure, as is well known, since it is composed of a sealed container and a working fluid injected into the container. As described above, the heat pipe has excellent characteristics such as a large heat transfer amount and no moving parts, despite its simple structure. Therefore, the heat pipe is used for heat transfer such as a heat exchanger and an air conditioner, a boiler, and a bath. It is also used as a heat sink for cooling a heating element such as a transistor or a thyristor. By the way, electronic devices used in electronic devices and power devices,
In particular, semiconductor elements tend to be highly integrated and have a large capacity, and the arrangement of the elements has been complicated accordingly. Since the arrangement of the electronic devices is thus complicated, a plurality of electronic devices may need to be attached to one heat sink. That is, depending on the layout of the electronic device or to reduce the manufacturing cost, it may be necessary to mount a plurality of electronic devices in the vertical direction on the evaporating portion of the heat pipe to cool the device.

A plurality of heating elements or electronic devices can be attached to the conventional heat sink as described above, so that the layout of the heating elements can be dealt with for the time being, and a certain degree of manufacturing cost can be obtained. . Depending on the conditions, it can be cooled to some extent. That is, even if a plurality of heating elements are attached to one heat sink, no particular problem occurs when the heating elements operate alternately to generate heat. However, when a plurality of heating elements, such as electronic devices, operate simultaneously to generate heat,
Electronic equipment may be damaged without being cooled sufficiently. More specifically, as described above, the heat pipe is composed of a closed vessel or pipe and the working fluid injected into the pipe, with the evaporating section being at the bottom and the condensing section being at the top. Be placed. Then,
In the evaporator, heat from the heating element is transmitted to the working fluid, and the working fluid evaporates. When the evaporating pressure increases, it moves toward the low pressure condensing part and condenses. And it returns to the evaporation part by gravity. When the working fluid circulates while changing the state, the heat of the heating element is released from the fin of the condensing section. By the way, in the heat sink as described above, when the evaporating portion is located on the side portion of the condensing portion and a plurality of heating elements are vertically attached to the evaporating portion, it is considered that the heating element attached above generates heat. In addition, the working fluid cannot circulate while changing the state, and the function of the heat pipe cannot be obtained. As a result, cooling of the heating element is prevented, and the heating element may be thermally damaged. Accordingly, the present applicant has developed a heat pipe type heat sink that can mount a plurality of heating elements vertically and that can sufficiently cool even if these heating elements generate heat at the same time, for example, as disclosed in Japanese Patent Application No. Hei. No. 134469. This heat pipe type heat sink is composed of a flat container,
The evaporating part is provided with a mounting part for mounting a plurality of heating elements, which is located on a side part of the condensing part. The flow paths through which the working fluid flows are independent of each other in correspondence with the mounting portions.

[0004]

As described above, since the flow path through which the working fluid flows is independent, even if a plurality of heating elements are mounted vertically and heat is generated at the same time, the operation of the heat pipe becomes defective. In addition, an excellent effect is obtained in that the heat generating element such as electronic equipment is not damaged by heat. However, since a flow path through which a plurality of working fluids flow is formed in one flat container, the flow path may be restricted or narrowed by a screw hole or the like for attaching a heating element. For this reason, when the individual heating elements generate heat, a flow of the working fluid may be defective. Therefore, in the present invention, a plurality of heating elements are attached in the vertical direction ,
It is an object of the present invention to provide a heat pipe type heat sink which operates even when these heat generating elements generate heat simultaneously or individually, and in which a flow path pattern through which a working fluid flows is not restricted.

[0005]

In order to achieve the above object, the present invention comprises a plurality of flat heat pipes, one of which is an evaporating section and the other is a condensing section. The heat pipe is laminated in multiple layers by brazing , and the flow pattern of the working fluid flows,
Make sure that each flat heat pipe is different.
Is done. The invention according to claim 2 is a steam generator according to claim 1.
The heating part is provided with a plurality of heating element mounting parts, and the working fluid
Flow path pattern corresponding to the heating element mounting portion
Each of the flat heat pipes is configured to be different .

[0006]

The required number of heating elements are attached to the evaporating section of the flat heat pipe. Then, the evaporating section is set so as to be positioned below as a whole. Then, the heat generated by the operating heating elements is transmitted from each flat heat pipe to the working fluid in the internal flow path, and the working fluid evaporates. Absorbs large amounts of latent heat when evaporated. Then, the vapor having increased vapor pressure moves toward the condensing section. In the condensing section, heat is released from the flat heat pipe to the outside, for example, in natural convection air, and the steam condenses. The condensed working fluid moves toward the evaporator due to gravity. Thereafter, the working fluid is circulated in the same manner to cool the heating element.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In carrying out the present invention, it is desirable to provide a fin in the condensing section of a flat heat pipe. Therefore, an embodiment in which fins are provided is shown in the drawing. The fin is configured as a heat radiation fin block from a plurality of fins and a plate-like substrate supporting these fins. The radiating fin block can be manufactured by bending a fin and a substrate from a single plate material, or can be formed integrally with a fin and a plate by separately forming the fin and the plate. . The radiating fin block integrally formed as a molded product as described above can be provided on only one surface of the flat heat pipe. However, the drawings show an embodiment provided on both sides.
Flat heat pipes can also be implemented in various ways. For example, it can also be formed by laminating two plate members formed by pressing. When three boards are stuck together,
Two flat heat pipes can be formed, and four flat heat pipes can be formed by bonding four heat pipes. At this time, recesses of a predetermined pattern are formed in the plate material, and these recesses are abutted and adhered to each other to form a flow path of a working fluid of a predetermined pattern inside. However,
FIG. 1 shows an embodiment in which one flat heat pipe is formed by a panel manufactured by a roll bonding method from two plate materials, and three flat heat pipes are stacked. When manufactured by the roll bonding method, the flow path can be easily formed, and the effect of withstanding the internal pressure even when the thickness is reduced can be obtained.

Hereinafter, embodiments of the present invention will be described. Referring to FIG. 1, a heat sink H according to the present embodiment includes first, second, and third flat heat pipes 10, 20,.
30 are stacked and the first flat heat pipe 10
It can be easily understood that the heat radiation fin blocks 40 and 40 'are provided on the surface of the third flat heat pipe 30 and a part of the surface thereof. In addition, the portions of the first, second, and third flat heat pipes 10, 20, 30 where the heat radiation fin blocks 40, 40 'are not provided may serve as the evaporating portion or the heating element mounting portion 17. It is easily understood by those skilled in the art. These components or members are formed of aluminum or an alloy thereof as described below.

The first flat heat pipe 10 has two sheets 11, 12 as shown in FIG.
And a flow area or flow path through which the working fluid flows is formed in a predetermined pattern. That is, in this embodiment, the first flat heat pipe 10
Is composed of a roll bond panel having a substantially square shape when viewed in plan. More specifically, a flow path of a predetermined shape is printed with a crimp-preventing material on a portion surrounded by a thin line, leaving the upper side portion 13, the side portions 14, 14 and the lower half portion 15 of the two sheets 11, 12, These sheets 11, 12
Rolled, crimped, and high pressure air was blown into the part where the crimp preventing material was printed and not crimped,
The flow path is formed by swelling. The flow path has an inverted L-shape. The upper channel portion is selected as the condenser 16, and the lower channel portion is selected as the evaporator 17. The first passage A is constituted by the condenser 16 and the evaporator 17. The evaporating section 17 also serves as a heating element mounting section. The heating element mounting portion 17 has first heating element mounting bolt holes 18, 18 at an upper position, second heating element mounting bolt holes 28, 28 at an intermediate position, and a second heating element mounting bolt hole 28 at a lowermost position. Bolt holes 38 for mounting the heating element 3 are formed respectively.

[0010] First heating element mounting bolt holes 18, 18
Are provided in or near the evaporating section 17, so that the first heating element mounting bolt holes 18, 1 are provided.
Attach the first heating element to 8, and when this heating element generates heat,
The first flow path A operates.

Second and third flat heat pipes 20, 30
Also, the overall configuration is the same as that of the first flat heat pipe 10 except for the shape of the flow path. That is, the second flow path B formed in the second flat heat pipe 20 is formed to be close to the bolt holes 28 for mounting the second heating element, and the second flow path B is formed in the third flat heat pipe 30. The third channel C is provided with bolt holes 18 for mounting the first, second, and third heating elements,
28 and 38 are formed so as to cover all of them. The other components are the same as those of the first flat heat pipe 20. Therefore, the corresponding components are denoted by changing the tens place of the reference numerals, and will not be described repeatedly.

The heat radiation fin blocks 40 and 40 'are shown in FIG.
As shown in FIG.
1 ', and flat substrates 42, 42'. In this embodiment, the fins 41 and 41 'and the substrates 42 and 42' are integrally formed. Substrates 40, 4
The area of 0 'is the first, second and third flat heat pipe 1
It is substantially equal to the area of the condensing parts 16, 26, 36 of 0, 20, 30.

The outer peripheral portions 13, 1 of the first, second, and third flat heat pipes 10, 20, 30 configured as described above.
Spacers and the like are appropriately placed in low places such as 4, 15 and the like, and the substrates 42, 42 'of the heat radiation fin blocks 40, 40' are condensed with the condensing portions 16, of the first and third flat heat pipes 10, 30.
36 and brazing, for example, by brazing in a furnace. In addition, brazing can be performed by heating in a vacuum furnace with a brazing sheet interposed, or brazing can be performed using a fluoride-based flux.

Although not shown in the drawing, the working fluid is supplied from the working fluid injection pipe through a pinch processing portion to each of the first, second and third flat heat pipes 10, 20 and 30 for each flow path A, B,
C. and seal the pinch. First, second,
3, bolt holes 18, 18, 28, 28,
The heating elements are attached using the respective 38, 38. Then, as shown in FIG. 1, the first heating element attached to the first heating element mounting bolt holes 18 is used so that the first heating element is positioned upward. Even when set in this way, since the respective flow paths A, B, and C are arranged in an inverted L-shape, the condenser 16 is located above the evaporator 17, and the condensed working fluid is supplied to the evaporator 17. Flows toward gravity by gravity.

Bolt holes 18, 18 for attaching the first heating element
The heat generated by the first heating element mounted on the first flat heat pipe 10 is operated by the first flow path A of the first flat heat pipe 10, and is transmitted to the working fluid in the evaporating section 17, and the working fluid is evaporated. Absorbs large amounts of latent heat when evaporated. Then, the vapor having increased vapor pressure moves toward the condensing section 16 having a lower vapor pressure.
Heat is transferred from the first flat heat pipe 10 to the fin 4
1, ... At this time, part of the heat is transmitted to the second and third flat heat pipes 20 and 30, and
1 ',. In the condensing section 16, the air flows between the fins 41 and 41 'by natural convection, so that the air is discharged into the air and the vapor condenses. The condensed working fluid moves toward the evaporator 17 due to gravity. Thereafter, the working fluid is circulated in the same manner to cool the first heating element. When the second heating element attached to the second heating element mounting bolt holes 28, 28 generates heat, the heat generated by the first heating element is radiated as described above. The body is mounted above the second heating element, but has no effect on the second flat heat pipe 20. Therefore, the second flow path B is operated, and the heat is transferred through the first or second flat heat pipes 20 and 30 to the fin 4.
, 41 ′,. It is apparent that the same effect is exerted when the third heating element attached to the third heating element mounting bolt holes 38, 38 generates heat.

[0016]

As described above, according to the present invention, the flat heat pipes are stacked in multiple layers by brazing, and the flow path pattern of the working fluid differs for each flat heat pipe. since, by attaching a plurality of heating elements in the vertical direction, even if the heat generation of these heating elements simultaneously, also the effect of specific obtain the present invention that it is possible to heat generation also sufficiently cooled individually. Moreover, since the flow path pattern through which the working fluid flows is different for each flat heat pipe, the flow path pattern through which the working fluid flows can be formed sufficiently wide without restriction.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a perspective view showing different embodiments of a flat heat pipe.

[Explanation of symbols]

10, 20, 30 First, second, third flat heat pipes 16, 26, 36 Condensing part 17, 27, 37 Evaporating part (heating element mounting part) 18, 28, 38 First, second, third heating element mounting Bolt holes 40, 40 'for heat radiation fin block A, B, C 1st, 2nd, 3rd flow path

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H05K 7/20 F28D 15/02 H01L 23/427

Claims (2)

(57) [Claims] 1. One is an evaporator and the other is a condenser.
Are composed of a plurality of flat heat pipes, and these flat heat pipes are stacked in multiple layers by brazing.
The flow path through which the working fluid flows while being layeredpattern
Is different for each flat heat pipe
A heat pipe type heat sink characterized by the following. 2. An evaporator according to claim 1, wherein a plurality of heat sources are provided.
A body attachment part is provided, and a flow path for the working fluid to flowpattern
Is for each flat heat pipe corresponding to the heating element mounting part.
Heat pipe type heat sink
H.