JPH10185468A - Plate heat pipe for inter-plane thermal diffusion coupling with maximal area ration - Google Patents

Abstract

(57) [Summary] [Purpose] The heat of a small, large heat-generating heating element is received in a small area, and this heat is diffused over an area of several hundred times, so that the heat-receiving element with a large heat receiving area can efficiently generate heat. To provide a plate heat pipe for inter-surface heat diffusion connection capable of transmitting heat. [Structure] Both inner walls of a plate-shaped container are formed in a heat connection structure which is mutually connected and supported by a fin group also serving as pressure-resistant reinforcement, and a flow path of a working fluid vapor formed by the fin group is a group of linear flow paths. Are arranged in a grid pattern crossing each other at right angles, and both inner wall surfaces of the plate-shaped container are uniformly maintained at intervals of 1 mm or more. Is a component having a wick of a predetermined structure mounted thereon, and the amount of the working fluid sealed and sealed in the container being 50% or less of the total internal volume. [Effect] The objective was completely achieved by the interaction of each component.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pipe used for heat diffusion connection between surfaces, and more particularly to a heat pipe interposed between a small adhesive surface of a small heat radiator and a large adhesive surface of a large heat receiver. The present invention relates to a structure of a plate heat pipe for inter-surface heat diffusion connection in which heat input from a small adhesive surface is evenly diffused to efficiently transport heat to a large adhesive surface.

[0002]

2. Description of the Related Art Conventional plate heat pipes which diffuse and transport heat by the phase change of a two-phase condensable hydraulic fluid have been applied mainly for transporting heat between surfaces rather than for connecting heat diffusion between surfaces. . However, in the plate heat pipe of the conventional design, as a basic characteristic of the plate heat pipe, the temperature uniformity of the plate surface was relatively good irrespective of the structure of the plate heat pipe container. It has also been used for interfacial heat diffusion connections in its original design. 8, 9, and 1
FIG. 1 illustrates the structure of a typical conventional plate heat pipe. FIG. 8 is an external perspective view of a plate heat pipe, and 11 is a plate heat pipe (container).
The broken line is a schematic diagram of the internal structure of the container. Reference numeral 12 denotes a group of support walls for reinforcing the pressure resistance of both planes of the container.
Reference numeral 12 also functions as a flow path for returning a condensed liquid of the working fluid vapor condensed on the inner wall surface of the heat radiation side to the inner wall surface of the heat receiving side. FIG. 9 is a partially enlarged view of a cross section orthogonal to the support wall group 12.
Indicates a cross section of the support wall. Reference numeral 16-1 denotes a wick formed on the surface of the support wall, which assists the recirculation of the working fluid from the inner wall surface on the heat radiation side to the heat receiving side wall surface. FIG. 10 is a partially enlarged view of a section parallel to the support wall group 12, and shows a hydraulic fluid flow hole 12-1 provided in the support wall 12. By the group of the circulation holes 12-1, the working liquid vapor can be freely distributed to all parts in the container.

The conventional plate heat pipe is an example of the above-described typical structure.
The flow in the lengthwise direction has a smaller fluid resistance than the flow in the direction perpendicular to the lengthwise direction, and shows better characteristics for heat transport in that direction. FIG. 11 shows an application example of a conventional plate heat pipe 11 which is applied to the use of heat transport between a heating element 14 having a planar contact surface and a heat receiving body 15 having a planar contact surface.

[0004]

The conventional plate heat pipe is mainly designed for efficient heat transfer between surfaces, and the heat resistance of heat transfer is reduced due to the rapid movement speed of the working fluid vapor. It is configured to be. However, in the conventional plate heat pipe, as a basic characteristic of the heat pipe, the temperature uniformity of the plate surface was relatively good irrespective of the plate heat pipe having any internal structure. It was considered as one of the functions, and there was hardly any special design for achieving a high degree of temperature uniformity.

However, due to the recent rapid development of semiconductor technology, semiconductor devices are becoming smaller and more powerful. When the heat of such a small and powerful semiconductor element (heat generating element) is transferred to a radiator (heat receiving element) through a plate heat pipe for inter-surface heat diffusion connection and the heat is cooled and radiated, the plate heat pipe and the semiconductor element are used. (Radiator) and a heat transfer area between
In some cases, the ratio of the heat transfer area between the plate heat pipe and the radiator (heat receiving body) (the heat dissipation ratio of the amount of heat) reaches 50 to 200 times or more.
When the inter-plane heat diffusion connection is performed with such a large heat diffusion magnification, the difference in pressure loss between the flow path groups of the working liquid vapor in the heat diffusion path is enlarged, and appears as a variation in the plate surface temperature, It becomes impossible to transfer heat while maintaining a uniform temperature over the entire surface of the heat diffusion connection surface. This means that there is uneven supply of heat to each part of the radiator (heat receiving body), which means that the radiator (heat receiving body) cannot exhibit the maximum performance.

From a different viewpoint, it is technically impossible for the radiator for cooling them to follow the downsizing of the semiconductor element in comparison with the progress of downsizing of the semiconductor element. If the heat-dissipating surface of the smaller radiator is connected to the larger-sized heat-receiving surface of the radiator, which must be enlarged to enhance the heat-dissipating ability, the surface heat of the heat Thermal resistance for diffusion is greatly added, and the heat dissipation efficiency is decreasing as the surface heat diffusion magnification increases. As a countermeasure against the decrease in the heat radiation efficiency, there has conventionally been no choice but to increase the size of the radiator because there is no effective means for connecting the heat diffusion between the surfaces.

In the industry, in order to improve the heat radiation efficiency in the heat diffusion connection with such a large heat diffusion magnification, the heat of the heat radiator is diffused uniformly and with a small thermal resistance to the heat receiving surface of the heat receiver.
There is a strong demand for the appearance of a plate heat pipe for interfacial heat diffusion connection capable of efficiently conducting heat transfer heat connection between the surfaces.

[0008]

The basic structure of a plate heat pipe for heat diffusion connection between surfaces as means for solving the problem will be described below. In order to avoid repetition, FIG. 1, FIG. 2, FIG. 3, FIG. 4, FIG. 5, and FIG. , And FIG. Heat receiving and radiating surface 1 of container 1 of plate heat pipe 1 for inter-surface heat diffusion connection
The mutual spacing between both inner wall surfaces corresponding to 1, 1-2 is extremely uniform and kept at a distance of 2 mm or more,
Both inner walls are mutually connected and supported by either the thin fin group 3 or the pin fin group 2 to form a thermal connection structure also serving as a pressure-resistant reinforcing structure, and are connected to either the thin fin group 3 or the pin fin group 2. The flow path of the working liquid vapor formed by the inner wall surface is a grid-like flow path formed by a group of linear flow paths having a width of 1.5 mm or more and a height of 2 mm or more crossing each other at right angles. A wick 6 having a predetermined structure is mounted in at least a fin gap between both inner wall surfaces of the heat pipe container on the heat receiving side inner wall surface, and a two-phase condensable hydraulic fluid sealed and sealed in the container. The basic structure is a structure characterized in that the enclosed amount is not more than 25% of the internal volume excluding the total volume of the thin fin group 3 or the pin fin group 2 from the total internal volume.

The above basic structure is composed of five components. Each of the components has a similar or known structure as a structure for heat transfer between surfaces, but is a structure that was conventionally overlooked as a component as a plate heat pipe for heat diffusion connection between surfaces. In addition, the excellent inter-surface heat diffusion connection function is not exhibited as an independent effect of each of the five components,
Achieved as an overall effect due to the interaction of the five combined components.

The basic function of the function is related to how the latent heat generated by the phase change of the working fluid is transferred to the heat radiating surface of the plate at a high speed, and how the entire surface of the heat radiating surface of the plate is transferred. It depends on whether the distribution is evenly distributed. That is, it depends on how to distribute and transport the working fluid vapor to each part of the inner wall surface corresponding to each part of the heat radiating surface of the plate at high speed and evenly.

The first of the five components corresponds to the inner wall surface corresponding to the heat receiving plane of the plate heat pipe container 1 and the heat radiation plane, which are illustrated in the partial cross-sectional enlarged views of FIG. 3, FIG. 5 and FIG. It is an essential condition that the mutual interval with the inner wall surface to be formed is highly uniform and the interval of 2 mm or more is maintained. In other words, the non-uniformity of the mutual spacing causes unevenness in the flow velocity of the working fluid vapor, which means unevenness in the pressure loss of the flow, which causes unevenness in heat transfer to the inner wall surface on the heat radiating side. This causes non-uniformity of not only the heat radiation side surface temperature of the plate heat pipe but also the entire surface temperature.

When the distance between the inner wall surfaces is 2 mm or less, a blockage due to the vapor condensate is generated at various places in the flow path of the hydraulic fluid due to the surface tension of the hydraulic fluid, and the blockage is generated at an unspecified position. The temperature of this part decreases because the working fluid vapor flows to avoid this part. The position of the closing portion is not limited to an unspecified one, and changes the closing position under a small operating condition. This causes not only variations in the surface temperature of the plate heat pipe but also instability of the surface temperature, which causes a reduction in heat transport capability.

The distance between the inner wall surfaces, which is a cause of the formation of a closed portion, differs depending on the type of the hydraulic fluid, that is, the viscosity of the hydraulic fluid, the surface tension, the temperature, and the like. Experimental results with respect to various working liquids such as pure water and Freon, which are liquids, have shown that the clogging phenomenon can be prevented by setting the interval to 2 mm or more. This means that the fin height must be 2 mm or more as a necessary condition.

Plate heat pipe 1 for heat diffusion connection between surfaces
The second component of FIG. 1 is a partially cutaway perspective view, and FIGS. 2 and 6 are partially cutaway plan views. It is an essential element that the fin gap of the pin fin group 2 is configured to be 1.5 mm or less. It is well known from the empirical value of the change in the pressure loss of the forced convection in the air that the pressure loss of the forced convection caused by the fins rapidly increases when the convection flow velocity is about 5 m / s and the fin gap is 1.5 mm or less. The steam flow rate in the plate heat pipe container 1 varies greatly depending on the amount of heat input and the temperature difference between the applied heat receiving and radiating sections, and the pressure loss of the steam flow changes extremely depending on the steam flow rate. However, since the moving distance of the working fluid vapor in the plate heat pipe 1 for heat diffusion connection between surfaces is a short distance,
If the flow rate is fast, then the pressure drop will increase significantly,
Even if the flow velocity is greatly reduced, the decrease in the heat transport amount and the increase in the plate temperature difference can be ignored.
In the case of a plate heat pipe for inter-surface heat diffusion connection, in order to guarantee a good heat diffusion performance even in the case of a heat connection with a small heat input of several watts or less and a small temperature difference such as 2-3 ° C. The working fluid vapor flow rate has a structure corresponding to a low flow rate of 5 m / sec or less. Since it is considered that the kinematic viscosity coefficient of water vapor at 80 ° C. under reduced pressure and the kinematic viscosity coefficient of air at 30 ° C. are almost equal, in the present invention, it should be configured approximately in the case of forced convection in air of 5 m / sec or less. And the fin gap was 1.5 mm or more. In the case of such a low flow turbulence, when the fin gap is set to 1.5 mm or less, the pressure loss sharply increases, the flow velocity is greatly reduced, and it is impossible to uniformly distribute steam to the inner wall surface of the container 1. Will be possible.

Plate heat pipe 1 for heat diffusion connection between surfaces
As can be seen from a partially cutaway perspective view of FIG. 1 and a partially cutaway plan view of FIGS. 2 and 6,
It is an essential element that the flow path of the working fluid vapor is configured to be a cross-shaped flow path formed by a group of linear flow paths crossing each other at right angles. The length of one side of the plate heat pipe 1 for inter-plane heat diffusion connection does not exceed 300 mm at most. With such a length, the straight flow path can guarantee the flow of steam without attenuation. The grid-like flow path formed by such a group of linear flow paths crossing each other at right angles ensures uniform distribution of latent heat to all portions on the inner wall surface of the plate-like container 1.

Plate heat pipe 1 for heat diffusion connection between surfaces
The fourth component is a wick 6-1 having a predetermined structure at least in the fin gap between both inner wall surfaces of the container of the plate heat pipe as shown in the partial cross-sectional enlarged view of FIG. It is an essential element that it is attached. The inner wall surface of the plate heat pipe 1 for heat diffusion connection between surfaces of the present invention has a structure in which the hydraulic fluid flows particularly easily. Therefore, when the holding posture at the time of application is slightly inclined, the hydraulic fluid in the initial state, the recirculating hydraulic fluid in the steady operation,
It operates in a state where it is unevenly retained on the inner wall surface on the container heat receiving side. In this case, it becomes impossible to effectively utilize all of the enclosed working fluid amount, and the heat connection performance of the plate heat pipe for interfacial heat diffusion connection is reduced. In addition, operating the hydraulic fluid in an unevenly distributed state on the inner wall surface of the container causes unevenness of the plate surface temperature. As a countermeasure, the distribution of hydraulic fluid on the inner wall surface of the container is leveled with the help of the capillary action of the wick. The wick 6-2 on the inner wall of the heat radiating side makes the distribution of the recirculating hydraulic fluid to the heat receiving side uniform.

Plate heat pipe 1 for heat diffusion connection between surfaces
The fifth component is that the enclosed amount of the two-phase condensable working fluid enclosed and sealed in the container 1 is the content obtained by subtracting the total volume of the thin fin group 3 or the pin fin group 2 from the total internal volume of the container. It is an essential element that it is 25% or less of the product. If the amount of the working fluid exceeds 25% of the internal volume of the container 1, a blockage and a stagnation portion of the condensed working fluid are formed at various places in the working fluid flow path, and a low-temperature portion is generated on the plate surface. These portions also impede the flow of the working fluid vapor flow and reduce the heat transfer capability of the plate heat pipe 1 for heat diffusion connection between surfaces.

[0018]

The five components of the plate heat pipe for inter-surface heat diffusion connection 1 described above have an interaction and an overall effect of reducing the amount of heat input from the small heat receiving surface of the contact portion with the small heating element 4. The surface is diffused evenly and with a small thermal resistance to the large heat radiation surface several hundred times larger, so that an excellent inter-surface heat diffusion connection function is exhibited.

[0019]

【Example】

[First Embodiment] FIGS. 1 to 3 show the structure of a first embodiment of a plate heat pipe for interfacial heat diffusion connection of the present invention.
Shows the application state. FIG. 1 is a perspective view showing a state where a part of a plate heat pipe 1 for inter-surface heat diffusion connection is cut off, and FIG.
1 is a plan view of FIG. 1, and FIG. 3 is a partially enlarged view of a cross section of FIG. Both inner wall surfaces of the container of the plate heat pipe 1 are thermally conductively connected to each other by a pin fin group 2, and the effective height of each pin of the pin fin group 2 as a fin is 2 m.
m or more, the pin arrangement of the pin fin group 2 is a grid pattern, and the gap between the pins in the grid pattern is 1.5 mm or more. Both inner wall surfaces of the container are formed exactly parallel and the distance between both inner wall surfaces is 2mm
It is formed so as to be as described above. The hydraulic fluid vapor flow path formed by the pin gap and both inner wall surfaces of the container is linear, and the vertical and horizontal groups of the vapor flow path group cross each other at right angles to each other according to the pin arrangement. It is formed like eyes. The amount of the two-phase condensable hydraulic fluid sealed and sealed in the container is not more than 25% of the total internal volume of the container minus the total volume of the pin fin group 2. Such a configuration completely satisfies the essential configuration of the basic structure of the plate heat pipe for inter-surface heat diffusion connection of the present invention. Therefore, the first embodiment exhibits the operation and effect as described in the basic structure.

The cross-sectional shape of each pin fin of the pin fin group 2 is circular because it is desirable that the pressure loss applied to the steam flow moving in all directions is the same in all directions and that the occurrence of pressure loss is small. Is most desirable. Elliptical pin fins are not preferred because pressure loss is small in a unidirectional steam flow, but pressure loss is severe in a flow in a direction perpendicular thereto, which impairs the uniformity of the plate surface temperature. A square cross section has a larger pressure loss than a circular one, but the pin fin group absorbs heat well, so depending on the type of hydraulic fluid and the applicable temperature range, the performance is better than that of a circular pin fin. There are cases. A pin fin formed with a group of fine grooves in the length direction has an effect of improving the performance because the capillary action assists the reflux of the condensed working fluid.

[Second Embodiment] FIGS. 6 and 7 show the structure of a second embodiment of the plate heat pipe for interfacial heat diffusion connection of the present invention. 6 is a plan view with a part cut away, and FIG. 7 is a sectional view. On each of the inner wall surfaces of the container of the heat connection plate heat pipe 1, thin fin groups 3-1 and 3-2 having a length equal to the entire length or the entire width of the inner wall surface are formed in parallel and parallel. The height of the thin plate fin groups 3-1 and 3-2 formed on each of the inner wall surfaces is 1 mm or more, and their total height is 2 mm or more. The gap between the thin fins 3 is 1.5 mm or more, and the thin fin group 3-1 on the inner wall surface on the heat receiving side and the thin fin group 3-2 on the inner wall surface on the heat radiating side intersect each other at right angles. The two thin fin groups 3-1 and 3-2 are arranged so as to form a shape.
Are joined to each other at their intersections,
A linear working fluid vapor flow path group formed by the thin fin groups 3-1 and 3-2 and both inner wall surfaces of the container is a cross-cut shape formed by the thin fin groups 3-1 and 3-2. It is cross-shaped in a grid pattern following the
It is characterized in that it is configured as a steam flow path substantially equivalent to a grid-like flow path formed by a group of working liquid vapor flow paths having a width of 1.5 mm or more. The volume of the two-phase condensable hydraulic fluid sealed and sealed in the container is not more than 25% of the total internal volume of the container minus the total volume of the fin groups 3-1 and 3-2. Such a configuration completely satisfies the essential configuration of the basic structure of the plate heat pipe for interfacial heat diffusion connection of the present invention. Therefore, the second embodiment exhibits the operation and effect as described in the basic structure.

[Third Embodiment] FIG. 5 is an explanatory view of a third embodiment of a plate heat pipe for inter-surface heat diffusion connection of the present invention, and is an enlarged view of a partial cross section. In the figure, 6-1 and 6-2 indicate wicks formed on the heat receiving side inner wall surface and the heat radiating side inner wall surface, respectively. Although not shown, the wick is provided on at least the inner wall surface on the heat receiving side of both inner wall surfaces of the container along a grid-like flow path of the working fluid vapor. Its detailed structure is a wick structure consisting of a linear body of stranded wires of a group of extra-fine metal wires, a group of vertical wires and a group of horizontal wires intersected in a grid pattern, press-fitted and bonded to the inner wall surface. . The linear body of the collective twisted wire makes the movement of the working fluid by capillary action quick and easy, and the cross-shaped crosses of the group disperse the working fluid quickly and uniformly over the entire inner wall surface of the container. The material of the wick 6 is naturally a metal having good thermal conductivity, but is preferably a soft metal in order to improve the retention by press-fitting into the pin gap and the inner wall surface of the container. Although the mounting of the wick 6 has a great effect only on the inner wall surface on the heat receiving side, the mounting on the inner wall surface on the heat radiating side also has a better effect in preventing the uneven return of the condensed hydraulic fluid. The group of fine grooves 2-1 formed in each pin 2 increases the flow rate of the recirculating hydraulic fluid from the inner wall surface on the heat radiation side to the inner wall surface on the heat receiving side due to the capillary action. Further improve heat transport performance.

[0023]

According to the interaction and overall effect of each component of the structure of the present invention, the amount of heat absorbed from the extremely small heat receiving surface of the contact portion with the small heating element attached to the plate heat pipe is converted to the large heat attached to the heat radiating surface. It has become possible to construct a plate heat pipe for inter-surface heat diffusion connection that diffuses and transports uniformly and quickly to the heat receiving surface of the radiator and does not lose heat radiation efficiency even if the surface heat diffusion ratio is several hundred times. . In particular, due to the application of such a plate heat pipe for inter-surface heat diffusion connection,
10mm × 10 emerged due to recent advances in semiconductor technology
A small semiconductor heating element that emits a large amount of heat, such as 120 watts, from an extremely small heat-radiating surface, such as mm, has a heat receiving area of 150 m.
Heat dissipation technology that was extremely difficult in the past, such as maintaining a temperature of a contact surface between a small heating element and a plate heat pipe at several tens of degrees Celsius using a radiator having a large total size of mx 150 mm and a relatively small total volume. Was completed.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing a basic structure and a first embodiment of a plate heat pipe for inter-surface heat diffusion connection of the present invention.

FIG. 2 is a partially cut-away plan view showing the basic structure and the first embodiment of the plate heat pipe for inter-surface heat diffusion connection of the present invention.

FIG. 3 is an enlarged explanatory view of a partial cross section showing a basic structure and a first embodiment of a plate heat pipe for inter-surface heat diffusion connection of the present invention.

FIG. 4 is an explanatory view showing an application state of the plate heat pipe for inter-surface heat diffusion connection of the present invention.

FIG. 5 is a partially enlarged cross-sectional view of a basic structure of a plate heat pipe for heat diffusion connection between surfaces according to the present invention and a third embodiment.

FIG. 6 is a plan view showing a basic structure of a plate heat pipe for inter-surface heat diffusion connection of the present invention and a part of the second embodiment cut away. .

FIG. 7 is an explanatory view of a side cross section of a second embodiment of the plate heat pipe for inter-surface heat diffusion connection of the present invention.

FIG. 8 is a perspective explanatory view of a conventional plate heat pipe.

FIG. 9 is an enlarged partial cross-sectional view of a side surface of a conventional plate heat pipe.

FIG. 10 is an enlarged partial cross-sectional view of another side surface of a conventional plate heat pipe.

FIG. 11 is an explanatory side view of an application example of a conventional plate heat pipe.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plate heat pipe for heat diffusion connection between surfaces 1-1 Container heat receiving surface 1-2 Container heat radiation surface 2 Pin fin group 2-1 Fine narrow groove group 3-1 Thin fin group 3-2 Thin fin group 3-3 Joint 4 Small heat generating element 5 Heat receiving element 5-1 Heat receiving element radiating fin group 6-1 Wick (heat receiving surface side) 6-2 Wick (heat releasing surface side) 11 Plate heat pipe 11-1 Container heat receiving surface 11-2 Container heat releasing surface 12 Support Wall group 12-1 Hydraulic fluid flow hole 14 Heating element 15 Heat receiving element

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[Procedure amendment]

[Submission date] February 21, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

[Document Name] Statement

[Title of the Invention] Plate heat pipe for heat diffusion connection between planes with maximum area ratio

[Claims]

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pipe used for heat diffusion connection between surfaces, and more particularly to a heat pipe interposed between a small adhesive surface of a small heat radiator and a large adhesive surface of a large heat receiver. The present invention relates to a structure of a plate heat pipe for inter-surface heat diffusion connection in which heat input from a small adhesive surface is evenly diffused to efficiently transport heat to a large adhesive surface.

[0002]

2. Description of the Related Art Conventional plate heat pipes which diffuse and transport heat by the phase change of a two-phase condensable hydraulic fluid have been applied mainly for transporting heat between surfaces rather than for connecting heat diffusion between surfaces. . However, in the plate heat pipe of the conventional design, as a basic characteristic of the plate heat pipe, the temperature uniformity of the plate surface was relatively good irrespective of the structure of the plate heat pipe container. It has also been used for interfacial heat diffusion connections in its original design. 8, 9, and 1
FIG. 1 illustrates the structure of a typical conventional plate heat pipe. FIG. 8 is an external perspective view of a plate heat pipe, and 11 is a plate heat pipe (container).
The broken line is a schematic diagram of the internal structure of the container. Reference numeral 12 denotes a group of support walls for reinforcing the pressure resistance of both planes of the container.
Reference numeral 12 also functions as a flow path for returning a condensed liquid of the working fluid vapor condensed on the inner wall surface of the heat radiation side to the inner wall surface of the heat receiving side. FIG. 9 is a partially enlarged view of a cross section orthogonal to the support wall group 12.
Indicates a cross section of the support wall. Reference numeral 16-1 denotes a wick formed on the surface of the support wall, which assists the recirculation of the working fluid from the inner wall surface on the heat radiation side to the heat receiving side wall surface. FIG. 10 is a partially enlarged view of a section parallel to the support wall group 12, and shows a hydraulic fluid flow hole 12-1 provided in the support wall 12. By the group of the circulation holes 12-1, the working liquid vapor can be freely distributed to all parts in the container.

The conventional plate heat pipe is an example of the above-described typical structure.
The flow in the lengthwise direction has a smaller fluid resistance than the flow in the direction perpendicular to the lengthwise direction, and shows better characteristics for heat transport in that direction. FIG. 11 shows an application example of a conventional plate heat pipe 11 which is applied to the use of heat transport between a heating element 14 having a planar contact surface and a heat receiving body 15 having a planar contact surface.

[0004]

The conventional plate heat pipe is mainly designed for efficient heat transfer between surfaces, and the heat resistance of heat transfer is reduced due to the rapid movement speed of the working fluid vapor. It is configured to be. However, in the conventional plate heat pipe, as a basic characteristic of the heat pipe, the temperature uniformity of the plate surface was relatively good irrespective of the plate heat pipe having any internal structure. It was considered as one of the functions, and there was hardly any special design for achieving a high degree of temperature uniformity.

However, due to the recent rapid development of semiconductor technology, semiconductor devices are becoming smaller and more powerful. When the heat of such a small and powerful semiconductor element (heat generating element) is transferred to a radiator (heat receiving element) through a plate heat pipe for inter-surface heat diffusion connection and the heat is cooled and radiated, the plate heat pipe and the semiconductor element are used. (Radiator) and a heat transfer area between
In some cases, the ratio of the heat transfer area between the plate heat pipe and the radiator (heat receiving body) (the heat dissipation ratio of the amount of heat) reaches 50 to 200 times or more.
When the inter-plane heat diffusion connection is performed with such a large heat diffusion magnification, the difference in pressure loss between the flow path groups of the working liquid vapor in the heat diffusion path is enlarged, and appears as a variation in the plate surface temperature, It becomes impossible to transfer heat while maintaining a uniform temperature over the entire surface of the heat diffusion connection surface. This means that there is uneven supply of heat to each part of the radiator (heat receiving body), which means that the radiator (heat receiving body) cannot exhibit the maximum performance.

From a different viewpoint, it is technically impossible for the radiator for cooling them to follow the downsizing of the semiconductor element in comparison with the progress of downsizing of the semiconductor element. If the heat-dissipating surface of the smaller radiator is connected to the larger-sized heat-receiving surface of the radiator, which must be enlarged to enhance the heat-dissipating ability, the surface heat of the heat Thermal resistance for diffusion is greatly added, and the heat dissipation efficiency is decreasing as the surface heat diffusion magnification increases. As a countermeasure against the decrease in the heat radiation efficiency, there has conventionally been no choice but to increase the size of the radiator because there is no effective means for connecting the heat diffusion between the surfaces.

In the industry, in order to improve the heat radiation efficiency in the heat diffusion connection with such a large heat diffusion magnification, the heat of the heat radiator is diffused uniformly and with a small thermal resistance to the heat receiving surface of the heat receiver.
There is a strong demand for the appearance of a plate heat pipe for interfacial heat diffusion connection capable of efficiently conducting heat transfer heat connection between the surfaces.

[0008]

The basic structure of a plate heat pipe for heat diffusion connection between surfaces as means for solving the problem will be described below. In order to avoid repetition, FIG. 1, FIG. 2, FIG. 3, FIG. 4, FIG. 5, and FIG. , And FIG. Heat receiving and radiating surface 1 of container 1 of plate heat pipe 1 for inter-surface heat diffusion connection
The mutual spacing between both inner wall surfaces corresponding to 1, 1-2 is extremely uniform and a spacing of 1 mm or more is maintained,
Both inner walls are mutually connected and supported by either the thin fin group 3 or the pin fin group 2 to form a thermal connection structure also serving as a pressure-resistant reinforcing structure. The flow path of the working liquid vapor formed by the inner wall surface is a grid-like flow path formed by a group of linear flow paths having a width of 0.8 mm or more and a height of 1 mm or more crossing each other at right angles. A wick 6 having a predetermined structure is mounted in at least a fin gap between both inner wall surfaces of the heat pipe container on the heat receiving side inner wall surface, and a two-phase condensable hydraulic fluid sealed and sealed in the container. The basic structure is characterized in that the enclosed amount is 50% or less of the total internal volume excluding the total volume of the thin fin group 3 or the pin fin group 2 from the total internal volume.

The above basic structure is composed of five components. Each of the components has a similar or known structure as a structure for transporting heat between surfaces, but a structure which has been overlooked as a component as a plate heat pipe for heat diffusion connection between surfaces. In addition, the excellent inter-surface heat diffusion connection function is not exhibited as an independent effect of each of the five components,
Achieved as an overall effect due to the interaction of the five combined components.

The basic function of the function is related to how the latent heat generated by the phase change of the working fluid is transferred to the heat radiating surface of the plate at a high speed, and how the entire surface of the heat radiating surface of the plate is transferred. It depends on whether the distribution is evenly distributed. That is, it depends on how to distribute and transport the working fluid vapor to each part of the inner wall surface corresponding to each part of the heat radiating surface of the plate at high speed and evenly.

The first of the five components corresponds to the inner wall surface corresponding to the heat receiving plane of the plate heat pipe container 1 and the heat radiation plane, which are illustrated in the partial cross-sectional enlarged views of FIG. 3, FIG. 5 and FIG. It is an essential condition that the distance between the inner wall surface and the inner wall surface is highly uniform and the distance of 1 mm or more is maintained. In other words, the non-uniformity of the mutual spacing causes unevenness in the flow velocity of the working fluid vapor, which means unevenness in the pressure loss of the flow, which causes unevenness in heat transfer to the inner wall surface on the heat radiating side. This causes non-uniformity of not only the heat radiation side surface temperature of the plate heat pipe but also the entire surface temperature.

When the mutual distance between the inner wall surfaces becomes 1 mm or less, a blockage due to the vapor condensate is generated at various places in the vapor flow path of the hydraulic fluid due to the surface tension of the hydraulic fluid, and the blockage is generated at an unspecified position. The temperature of this part decreases because the working fluid vapor flows to avoid this part. The position of the closing portion is not limited to an unspecified one, and changes the closing position under a small operating condition. This causes not only variations in the surface temperature of the plate heat pipe but also instability of the surface temperature, which causes a reduction in heat transport capability.

The distance between the inner wall surfaces, which is a cause of the formation of a closed portion, differs depending on the type of the hydraulic fluid, that is, the viscosity of the hydraulic fluid, the surface tension, the temperature, and the like. Experimental results with respect to various working liquids such as pure water and chlorofluorocarbon have shown that the clogging phenomenon can be prevented by setting the interval to 1 mm or more. This means that the fin height must be 1 mm or more as a necessary condition.

Plate heat pipe 1 for heat diffusion connection between surfaces
The second component of FIG. 1 is a partially cutaway perspective view, and FIGS. 2 and 6 are partially cutaway plan views. It is an essential element that the fin gap of the pin fin group 2 is configured to be 0.8 mm or less. It is well known from the empirical value of the change in the pressure loss of the forced convection in the air that the pressure loss of the forced convection due to the fin rapidly increases when the convection flow velocity is about 5 m / s and the fin gap is 0.8 mm or less. The steam flow rate in the plate heat pipe container 1 varies greatly depending on the amount of heat input and the temperature difference between the applied heat receiving and radiating sections, and the pressure loss of the steam flow changes extremely depending on the steam flow rate. However, since the moving distance of the working fluid vapor in the plate heat pipe 1 for heat diffusion connection between surfaces is a short distance,
If the flow rate is fast, then the pressure drop will increase significantly,
Even if the flow velocity is greatly reduced, the decrease in the heat transport amount and the increase in the plate temperature difference can be ignored.
In order to guarantee good heat diffusion performance even in the case of a micro heat input of several watts or less in the case of a plate heat pipe for inter-surface heat diffusion connection and a micro temperature difference of 2-3 ° C. The working fluid vapor flow velocity has a structure corresponding to a low flow velocity of 5 m / sec or less. Since it is considered that the kinematic viscosity coefficient of water vapor at 80 ° C. under reduced pressure and the kinematic viscosity coefficient of air at 30 ° C. are almost equal, in the present invention, it should be configured approximately in the case of forced convection in air of 5 m / sec or less. And the fin gap was 0.8 mm or more. In the case of such a low flow velocity, when the fin gap is set to 0.8 mm or less, the pressure loss increases sharply, the flow velocity drastically decreases, and it is impossible to evenly distribute steam to the inner wall surface of the container 1. become.

Plate heat pipe 1 for heat diffusion connection between surfaces
As can be seen from a partially cutaway perspective view of FIG. 1 and a partially cutaway plan view of FIGS. 2 and 6,
It is an essential element that the flow path of the working fluid vapor is configured to be a cross-shaped flow path formed by a group of linear flow paths crossing each other at right angles. The length of one side of the plate heat pipe 1 for inter-plane heat diffusion connection does not exceed 300 mm at most. With such a length, the straight flow path can guarantee the flow of steam without attenuation. The grid-like flow path formed by such a group of linear flow paths crossing each other at right angles ensures uniform distribution of latent heat to all portions on the inner wall surface of the plate-like container 1.

Plate heat pipe 1 for heat diffusion connection between surfaces
The fourth component is a wick 6-1 having a predetermined structure in at least a fin gap between both inner wall surfaces of the container of the plate heat pipe as shown in the partial cross-sectional enlarged view of FIG. It is an essential element that it is attached. The inner wall surface of the plate heat pipe 1 for heat diffusion connection between surfaces of the present invention has a structure in which the hydraulic fluid flows particularly easily. Therefore, when the holding posture at the time of application is slightly inclined, the hydraulic fluid in the initial state, the recirculating hydraulic fluid in the steady operation,
It operates in a state where it is unevenly retained on the inner wall surface on the container heat receiving side. In this case, it becomes impossible to effectively utilize all of the enclosed working fluid amount, and the heat connection performance of the plate heat pipe for interfacial heat diffusion connection is reduced. In addition, operating the hydraulic fluid in an unevenly distributed state on the inner wall surface of the container causes unevenness of the plate surface temperature. As a countermeasure, the distribution of hydraulic fluid on the inner wall surface of the container is leveled with the help of the capillary action of the wick. The wick 6-2 on the inner wall of the heat radiating side makes the distribution of the recirculating hydraulic fluid to the heat receiving side uniform.

Plate heat pipe 1 for heat diffusion connection between surfaces
The fifth component is that the enclosed amount of the two-phase condensable working fluid enclosed and sealed in the container 1 is the content obtained by subtracting the total volume of the thin fin group 3 or the pin fin group 2 from the total internal volume of the container. It is an essential element that it is 50% or less of the product. If the amount of the working fluid exceeds 50% of the inner volume of the container 1, a blockage and a stagnation portion of the condensed working fluid are formed at various places in the working fluid flow path, and a low-temperature portion is generated on the plate surface. These portions also impede the flow of the working fluid vapor flow and reduce the heat transfer capability of the plate heat pipe 1 for heat diffusion connection between surfaces.

[0018]

The five components of the plate heat pipe for inter-surface heat diffusion connection 1 described above have an interaction and an overall effect of reducing the amount of heat input from the small heat receiving surface of the contact portion with the small heating element 4. The surface is diffused evenly and with a small thermal resistance to the large heat radiation surface several hundred times larger, so that an excellent inter-surface heat diffusion connection function is exhibited.

[0019]

[First Embodiment] FIGS. 1 to 3 show the structure of a first embodiment of a plate heat pipe for interfacial heat diffusion connection of the present invention, and FIGS.
Shows the application state. FIG. 1 is a perspective view showing a state where a part of a plate heat pipe 1 for inter-surface heat diffusion connection is cut off, and FIG.
1 is a plan view of FIG. 1, and FIG. 3 is a partially enlarged view of a cross section of FIG. Both inner wall surfaces of the container of the plate heat pipe 1 are thermally conductively connected to each other by a pin fin group 2, and the effective height of each pin of the pin fin group 2 as a fin is 1 m.
m or more, the pin arrangement of the pin fin group 2 is a grid pattern, and the gap between the pins in the grid pattern is 0.8 mm or more. Both inner wall surfaces of the container are formed exactly parallel and the distance between both inner wall surfaces is 2mm
It is formed so as to be as described above. The hydraulic fluid vapor flow path formed by the pin gap and both inner wall surfaces of the container is linear, and the vertical and horizontal groups of the vapor flow path group cross each other at right angles to each other according to the pin arrangement. It is formed like eyes. The volume of the two-phase condensable working fluid sealed and sealed in the container is 50% or less of the total internal volume of the container minus the total volume of the pin fin group 2. Such a configuration completely satisfies the essential configuration of the basic structure of the plate heat pipe for inter-surface heat diffusion connection of the present invention. Therefore, the first embodiment exhibits the operation and effect as described in the basic structure.

The cross-sectional shape of each pin fin of the pin fin group 2 is circular because it is desirable that the pressure loss applied to the steam flow moving in all directions is the same in all directions and that the occurrence of pressure loss is small. Is most desirable. Elliptical pin fins are not preferred because pressure loss is small in a unidirectional steam flow, but pressure loss is severe in a flow in a direction perpendicular thereto, which impairs the uniformity of the plate surface temperature. A square cross section has a larger pressure loss than a circular one, but the pin fin group absorbs heat well, so depending on the type of hydraulic fluid and the applicable temperature range, the performance is better than that of a circular pin fin. There are cases. A pin fin formed with a group of fine grooves in the length direction has an effect of improving the performance because the capillary action assists the reflux of the condensed working fluid.

[Second Embodiment] FIGS. 6 and 7 show the structure of a second embodiment of the plate heat pipe for interfacial heat diffusion connection of the present invention. 6 is a plan view with a part cut away, and FIG. 7 is a sectional view. On each of the inner wall surfaces of the container of the heat connection plate heat pipe 1, thin fin groups 3-1 and 3-2 having a length equal to the entire length or the entire width of the inner wall surface are formed in parallel and parallel. The height of the thin plate fin groups 3-1 and 3-2 formed on each of the inner wall surfaces is 0.5 mm or more, and the total height thereof is 1 mm or more. The gap between the thin fins 3 is 0.8 mm or more, and the thin fin group 3-1 on the inner wall surface on the heat receiving side and the thin fin group 3-2 on the inner wall surface on the heat radiating side intersect each other at right angles. The two thin fin groups 3-1 and 3 are arranged so as to form a shape.
-2 are joined to each other at their intersections, and a linear working fluid vapor flow path group formed by the thin plate fin groups 3-1 and 3-2 and both inner wall surfaces of the container is a thin plate fin. The fins 3-1 and 3-2 are formed in a cross-shaped pattern following the cross-shaped pattern formed by the fin groups 3-1, 3-2, and are formed by a group of hydraulic fluid vapor flow paths having a height of 1 mm or more and a width of 0.8 mm or more. It is characterized in that it is configured as a steam flow path substantially equivalent to the grid-like flow path. The volume of the two-phase condensable hydraulic fluid sealed and sealed in the container is 50% or less of the total internal volume of the container minus the total volume of the fin groups 3-1 and 3-2. Such a configuration completely satisfies the essential configuration of the basic structure of the plate heat pipe for interfacial heat diffusion connection of the present invention. Therefore, the second embodiment exhibits the operation and effect as described in the basic structure.

[Third Embodiment] FIG. 5 is an explanatory view of a third embodiment of a plate heat pipe for inter-surface heat diffusion connection of the present invention, and is an enlarged view of a partial cross section. In the figure, 6-1 and 6-2 indicate wicks formed on the heat receiving side inner wall surface and the heat radiating side inner wall surface, respectively. Although not shown, the wick is provided on at least the inner wall surface on the heat receiving side of both inner wall surfaces of the container along a grid-like flow path of the working fluid vapor. Its detailed structure is a wick structure consisting of a linear body of stranded wires of a group of extra-fine metal wires, a group of vertical wires and a group of horizontal wires intersected in a grid pattern, press-fitted and bonded to the inner wall surface. . The linear body of the collective twisted wire makes the movement of the working fluid by capillary action quick and easy, and the cross-shaped crosses of the group disperse the working fluid quickly and uniformly over the entire inner wall surface of the container. The material of the wick 6 is naturally a metal having good thermal conductivity, but is preferably a soft metal in order to improve the retention by press-fitting into the pin gap and the inner wall surface of the container. Although the mounting of the wick 6 has a great effect only on the inner wall surface on the heat receiving side, the mounting on the inner wall surface on the heat radiating side also has a better effect in preventing the uneven return of the condensed hydraulic fluid. The group of fine grooves 2-1 formed in each pin 2 increases the flow rate of the recirculating hydraulic fluid from the inner wall surface on the heat radiation side to the inner wall surface on the heat receiving side due to the capillary action. Further improve heat transport performance.

[0023]

According to the interaction and overall effect of each component of the structure of the present invention, the amount of heat absorbed from the extremely small heat receiving surface of the contact portion with the small heating element attached to the plate heat pipe is converted to the large heat attached to the heat radiating surface. It has become possible to construct a plate heat pipe for inter-surface heat diffusion connection that diffuses and transports uniformly and quickly to the heat receiving surface of the radiator and does not lose heat radiation efficiency even if the surface heat diffusion ratio is several hundred times. . In particular, due to the application of such a plate heat pipe for inter-surface heat diffusion connection,
10mm × 10 emerged due to recent advances in semiconductor technology
A small semiconductor heating element that emits a large amount of heat, such as 120 watts, from an extremely small heat-radiating surface, such as mm, has a heat receiving area of 150 m.
Heat dissipation technology that was extremely difficult in the past, such as maintaining a temperature of a contact surface between a small heating element and a plate heat pipe at several tens of degrees Celsius using a radiator having a large total size of mx 150 mm and a relatively small total volume. Was completed.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing a basic structure and a first embodiment of a plate heat pipe for inter-surface heat diffusion connection of the present invention.

FIG. 2 is a partially cut-away plan view showing the basic structure and the first embodiment of the plate heat pipe for inter-surface heat diffusion connection of the present invention.

FIG. 3 is an enlarged explanatory view of a partial cross section showing a basic structure and a first embodiment of a plate heat pipe for inter-surface heat diffusion connection of the present invention.

FIG. 4 is an explanatory view showing an application state of the plate heat pipe for inter-surface heat diffusion connection of the present invention.

FIG. 5 is a partially enlarged cross-sectional view of a basic structure of a plate heat pipe for inter-surface heat diffusion connection of the present invention and a third embodiment.

FIG. 6 is a plan view showing a basic structure of a plate heat pipe for inter-surface heat diffusion connection of the present invention and a part of the second embodiment cut away. .

FIG. 7 is an explanatory view of a side cross section of a second embodiment of the plate heat pipe for inter-surface heat diffusion connection of the present invention.

FIG. 8 is a perspective explanatory view of a conventional plate heat pipe.

FIG. 9 is an enlarged partial cross-sectional view of a side surface of a conventional plate heat pipe.

FIG. 10 is an enlarged partial cross-sectional view of another side surface of a conventional plate heat pipe.

FIG. 11 is an explanatory side view of an application example of a conventional plate heat pipe.

[Description of Signs] 1 Plate heat pipe for heat diffusion connection between surfaces 1-1 Container heat receiving surface 1-2 Container heat radiation surface 2 Pin fin group 2-1 Fine narrow groove group 3-1 Thin plate fin group 3-2 Thin plate fin group 3 -3 Joining part 4 Small heating element 5 Heat receiving body 6-1 Wick (heat receiving surface side) 6-2 Wick (heat radiating surface side) 11 Plate heat pipe 11-1 Container heat receiving surface 11-2 Container heat radiating surface 12 Support wall group 12 -1 Hydraulic fluid flow hole 14 Heating element 15 Heating element

Claims (4)

[Claims] An input from a small heat radiator having an extremely small heat radiation bonding surface which is surface bonded to a part of a flat surface on one side of a plate heat pipe which diffuses and transports heat by the phase change of a two-phase condensable working fluid. The surface heat is diffused evenly, and the large-area heat-receiving body having a large heat-receiving surface bonded to the other one-side flat surface has a maximum heat-receiving surface, and the heat-receiving surface is maintained at a uniform temperature. The heat diffusion connection plate heat pipe, the mutual interval between the two inner wall surfaces corresponding to the heat receiving and radiating surface of the container of the plate heat pipe is extremely uniform and a distance of 2 mm or more is maintained, Both inner walls are connected and supported by either a thin fin group or a pin fin group to form a thermal connection structure that also serves as a pressure-resistant reinforcing structure. The flow path of the working liquid vapor formed by any one of the inner wall surfaces is a grid-like flow path formed by a group of linear flow paths having a width of 1.5 mm or more and a height of 2 mm or more crossing each other at right angles. There is a wick of a predetermined structure installed in the fin gap on at least the inner wall surface on the heat receiving side of both inner wall surfaces of the plate heat pipe container, and the two-phase condensate sealed and sealed in the container The amount of working fluid enclosed is not more than 25% of the total volume of the container excluding the total volume of the thin fin group or the pin fin group, and the plate heat for interfacial heat diffusion connection having a maximum area ratio. pipe. 2. The two inner wall surfaces of the container of the plate heat pipe are thermally connected to each other by a plurality of pin fin groups, and the effective height of each pin of the pin fin group as a fin is 2 mm or more; The pin arrangement of the pin fin group is a grid pattern, and the gap between the pins in the grid pattern is 1.
A plate heat pipe for interfacial heat diffusion connection having a maximum area ratio of 5 mm or more. 3. A thin plate fin group having a length equal to the entire length or full width of the inner wall surface is formed in parallel and parallel on each of both inner wall surfaces of the plate heat pipe container, and the height of the thin plate fin group is 1 mm. The gap between the thin fins is 1.5 mm or more, and the thin fin group on the inner wall surface on the heat receiving side and the thin fin group on the inner wall surface on the heat radiation side have a working fluid vapor flow path formed by the thin fin group. They are mutually orthogonally crossed and abutted, and form a vapor flow path substantially equivalent to a grid-like flow path formed by a group of hydraulic liquid vapor flow paths having a height of 2 mm or more and a width of 1.5 mm or more. 2. The heat diffusion connection according to claim 1, wherein both of the thin fin groups are arranged so as to be thermally conductively joined to each other at their intersections. For plate heat pipe. 4. A vertical line formed of a set of stranded wires of a group of ultrafine metal wires along at least one of the inner wall surfaces of the container on the heat receiving side along a grid-like flow path of the working fluid vapor. The heat diffusion connection according to claim 1, wherein the group of the horizontal lines and the group of the horizontal lines are press-fitted in a checkerboard shape, are pressed and adhered to the inner wall surface, and are formed as a wick. For plate heat pipe.