TWI576556B - Evaporator, cooling apparatus and electronic apparatus - Google Patents

Description

Evaporator, cooling device and electronic device Field of invention

The invention relates to an evaporator, a cooling device and an electronic device.

Background of the invention

The cooling device for cooling a heating element such as an electronic component mounted on an electronic device such as a computer has a latent heat of vaporization by a liquid phase actuating fluid to be a gas phase actuating fluid, thereby achieving high cooling performance. Phase flow cooling device.

Such a cooling device has, for example, an evaporator having a porous body (capillary structure) and a condenser, the outlet of the evaporator is connected to the inlet of the condenser by a vapor tube, and the outlet of the condenser and the inlet of the evaporator are connected by a liquid tube. A loop heat pipe (LHP: Loop Heat Pipe) in which an actuating fluid is enclosed.

In such a loop type heat pipe, for example, the working fluid can be circulated by the capillary force of the porous body without using a liquid transfer pump or the like to transfer heat.

Further, in the evaporator having the loop type heat pipe as described above, when a flat porous body is used, the evaporation area is small and sufficient cooling cannot be obtained. performance. Therefore, in order to increase the evaporation area and improve the cooling performance, it is possible to provide irregularities on the porous body and the heating surface, and to be fitted to each other. Further, a plurality of protrusions are formed in the casing that serves as the heat transfer portion, and the porous bodies are embedded in the plurality of protrusions.

Advanced technical literature [Patent Literature]

[Patent Document 1] US Patent No. 4765396

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2007-247931

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2009-115396

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2013-257129

[Patent Document 5] Japanese Patent Laid-Open Publication No. 2003-185370

Summary of invention

However, when the porous body and the heating surface are provided with irregularities and are fitted to each other, the porous body is placed such that the concave portion between the convex portion and the convex portion of the heating surface is buried, for example, in a heating element. When the amount of heat generation increases and the amount of evaporation increases, it becomes difficult for the liquid phase actuating fluid to be supplied to the end portion of the heating surface side of the porous body. As a result, dryness is generated, the evaporation area becomes small, and the cooling performance is lowered.

In order to prevent this, it is conceivable to provide a plurality of protrusions in the case of the heat transfer portion, and to embed the porous body in each of the plurality of protrusions, thereby forming a liquid phase fluid to flow to the protrusions in which the porous body is embedded. The space around it.

However, when a liquid phase actuating fluid flows in a space around the respective projections in which the porous body is embedded, the area of the liquid contact surface where the liquid phase of the porous body contacts the working fluid becomes large. Further, when the area of the liquid contact surface in contact with the liquid phase of the porous body becomes large, heat leakage from the porous body to the liquid phase working fluid increases, and the cooling performance is lowered.

Therefore, it is desirable to reduce the heat leakage from the porous body to the liquid phase, and to suppress the decrease in the cooling performance, thereby obtaining stable cooling performance.

The evaporator includes: a porous body having a plurality of cylindrical convex portions; a vapor chamber and a liquid chamber separated by the porous body; and a casing having: a first portion connecting the vapor tube and defining the vapor chamber; The liquid pipe defines a second portion of the liquid chamber; and a plurality of protrusions are provided on the first portion and protrude toward the side of the second portion, and are embedded in each of the plurality of cylindrical convex portions of the porous body. And a plurality of masks covering the surfaces of the plurality of cylindrical convex portions to reduce the area of the liquid contact surface of the liquid electrolyte fluid contacting the plurality of cylindrical convex portions of the porous body.

The cooling device comprises: an evaporator for evaporating the liquid phase working fluid; a condenser for condensing the gas phase working fluid; a vapor tube connecting the evaporator and the condenser and for flowing the gas phase working fluid; and connecting the condensation And the foregoing evaporator, and a liquid pipe for the liquid phase to move the fluid, the evaporator having: a porous body having a plurality of cylindrical protrusions; a vapor chamber and a liquid chamber separated by the porous body; Having a first portion of the vapor chamber connected to the vapor tube, a second portion connecting the liquid tube and defining the liquid chamber, and a plurality of protrusions provided in the first portion a side of the second portion protruding from each of the plurality of cylindrical convex portions of the porous body; and a plurality of masks covering the surfaces of the plurality of cylindrical convex portions to make the porous body The area of the liquid contact surface of the plurality of cylindrical convex portions contacting the liquid phase working fluid becomes small.

The electronic device includes: an electronic component disposed on the wiring substrate, and a cooling device for cooling the electronic component, wherein the cooling device includes: an evaporator that evaporates the liquid phase working fluid; and condenses the gas phase active fluid condensation a vapor tube connecting the evaporator and the condenser and supplying a gas flow to the gas phase; and a liquid pipe connecting the condenser and the evaporator and flowing the liquid to actuate the fluid, the evaporator having: a plurality a porous body having a cylindrical convex portion; a vapor chamber and a liquid chamber partitioned by the porous body; and a casing having a first portion for connecting the vapor tube and defining the vapor chamber; and connecting the liquid tube and defining the liquid chamber a second portion; and a plurality of protrusions are provided on the first portion and protrude toward the side of the second portion, and are embedded in each of the plurality of cylindrical protrusions of the porous body; and a plurality of masks are used The surface of each of the plurality of cylindrical convex portions is covered so that the area of the liquid contact surface of the plurality of cylindrical convex portions contacting the liquid phase working fluid of the porous body is reduced.

Therefore, according to the present evaporator, the cooling device and the electronic device have heat leakage which can reduce the flow of the fluid from the porous body to the liquid phase, and suppress the decrease in the cooling performance, thereby obtaining stable cooling performance.

1‧‧‧Cooling device (circuit type heat pipe)

2‧‧‧Evaporator

3‧‧‧Condenser

4‧‧‧Vapor tube

5‧‧‧ liquid tube

6‧‧‧Porous body

6A‧‧‧Cylindrical convex

6B‧‧‧flat part

6C‧‧‧ insertion hole

6D‧‧‧Ditch

6X‧‧‧liquid level

6Y‧‧‧Evaporation surface

61A‧‧‧1st cylindrical protrusion

62A‧‧‧2nd cylindrical protrusion

63A‧‧‧3rd cylindrical protrusion

64A‧‧‧4th cylindrical protrusion

7‧‧ ‧ vapor room

8‧‧‧ liquid room

9‧‧‧Shell

9A‧‧‧lower part

9AX‧‧‧ bottom plate

9AY‧‧‧ recess

9B‧‧‧ upper part

9BX‧‧‧ frame

9BY‧‧‧ cover

9C‧‧‧Protruding

9D‧‧‧ opening for steam pipe connection

9E‧‧‧ opening for liquid pipe connection

10‧‧‧ mask

10A‧‧‧ openings

10B‧‧‧ hole

10C‧‧‧ slots

10D‧‧‧ slot

10E‧‧‧Flow

10F‧‧‧ditch

10G‧‧‧ Protrusion

10H‧‧‧Porous body mask

101‧‧‧Part 1

102‧‧‧Part 2

103‧‧‧Part 3

104‧‧‧Part 4

105‧‧‧ plate-shaped part

10-1~10-4‧‧‧4 adjacent masks

101-1~101-4‧‧‧One part of each of the four adjacent masks

11‧‧‧Liquid actuating fluid (actuating fluid)

50‧‧‧Shell

51‧‧‧Electronic parts

51X‧‧‧CPU (heating body; heating parts; electronic parts)

52‧‧‧Wiring substrate

53‧‧‧Send fan

54‧‧‧Power supply

55‧‧‧HDD

56‧‧‧ Thermal paste

57‧‧‧heating fan

Figure 1 is a view showing evaporation of a cooling device provided in the present embodiment. A schematic cross-sectional view of the composition of the device.

Fig. 2 is an exploded perspective view showing a configuration of an evaporator (a mask having a first specific example of a specific configuration example) provided in the cooling device of the embodiment.

Fig. 3 is a schematic perspective view showing a configuration of a cooling device and an electronic device having the same according to the embodiment.

4(A) and 4(B) are schematic views for explaining the problem of the present invention, and FIG. 4(A) is a cross-sectional view along the height direction of the projection provided in the casing, and FIG. 4(FIG. 4( B) is a cross-sectional view along the radial direction of the protrusion provided in the casing.

Fig. 5 is a schematic cross-sectional view showing the action and effect of the mask provided in the evaporator of the cooling device of the embodiment, Figs. 5(A) and 5(B), and Fig. 5(A) shows no. In the case where a mask is provided, FIG. 5(B) shows a case where no mask is provided.

6(A) and 6(B) are diagrams showing the results of a cooling test in the case where the mask of the first specific example is used in the cooling device of the specific configuration example of the embodiment, and FIG. 6(A) shows the measurement. As a result of the temperature of the bottom surface of the evaporator, Fig. 6(B) shows the result of measuring the temperature above the evaporator.

FIG. 7 is a schematic perspective view showing a configuration of a modification (a mask of a second specific example of a specific configuration example) of a mask provided in the evaporator of the cooling device of the embodiment.

8(A) and 8(B) show the results of a cooling test in the case of using the mask of the second specific example of the cooling device according to the specific configuration example of the embodiment, and FIG. 8(A) shows the measurement. The result of the evaporator bottom temperature, Figure 8 (B) shows the result of measuring the temperature above the evaporator.

FIG. 9 is a schematic perspective view showing a configuration of a modification (a mask of a third specific example of a specific configuration example) of a mask provided in the evaporator of the cooling device of the embodiment.

Fig. 10 (A) and Fig. 10(B) show the results of a cooling test in the case where the mask of the third specific example is used in the cooling device of the specific configuration example of the embodiment, and Fig. 10(A) shows the measurement. As a result of the temperature of the bottom surface of the evaporator, Fig. 10(B) shows the result of measuring the temperature above the evaporator.

Fig. 11 is a schematic perspective view showing a configuration of a modification of the mask provided in the evaporator of the cooling device of the embodiment.

Fig. 12 is a schematic perspective view showing a configuration of a modification of a mask provided in the evaporator of the cooling device of the embodiment.

Fig. 13 is a schematic perspective view showing a configuration of a modification of the mask provided in the evaporator of the cooling device of the embodiment.

FIG. 14 is a schematic plan view showing a state in which a mask of a modified example is provided in a cylindrical convex portion of a porous body of an evaporator provided in the cooling device of the present embodiment.

Fig. 15 is a schematic cross-sectional view showing a configuration of a modification of the evaporator provided in the cooling device of the embodiment.

Fig. 16 is a schematic view showing a configuration of a modification of the mask provided in the evaporator of the cooling device of the embodiment, Fig. 16 (A) and Fig. 16 (B), and Fig. 16 (A) is a perspective view, Fig. 16 (B) is a cross-sectional view.

Fig. 17 is a schematic perspective view showing a configuration of a modification of the mask provided in the evaporator of the cooling device of the embodiment.

Detailed description of the preferred embodiment

Hereinafter, an evaporator, a cooling device, and an electronic device according to an embodiment of the present invention will be described with reference to FIGS. 1 to 17 with reference to the drawings.

The cooling device of the present embodiment is a cooling device for cooling a heating element such as an electronic component of an electronic device such as a computer (for example, a server or a personal computer). Furthermore, electronic devices are also referred to as electronic devices. Further, the electronic component is, for example, a CPU or an LSI chip.

First, as shown in FIG. 3, the electronic device of the present embodiment includes a wiring board 52 (for example, a printed wiring board) mounted on a plurality of electronic components 51 in the casing 50, and electronic components on the wiring board 52. 51 air-cooled delivery fan 53, power supply 54, and HDD (Hard Disk Drive) 55 as an auxiliary memory device.

Further, among the plurality of electronic components 51, an electronic component as a heating element, that is, a heat generating component 51X is included. Here, the heat generating component includes a CPU (Central Processing Unit) 51X. The CPU 51X as the heat generating component is because the light is not sufficiently cooled by the air blown by the blower fan 53, and the cooling device 1 (here, a loop type heat pipe) is attached to cool it.

In the present embodiment, the cooling device 1 is a cooling device that realizes high cooling performance by using a gas-liquid two-phase flow and evaporating the working fluid in a liquid phase (liquid state) to become a working fluid in a gas phase (gas state). .

That is, the cooling device 1 has an evaporator 2 for evaporating a liquid phase working fluid, a condenser 3 for condensing a gas phase actuating fluid, and a connection evaporator 2 and a condenser 3 and a vapor tube 4 for supplying a gas-phase working fluid, and a liquid tube 5 for connecting the condenser 3 and the evaporator 2 and for supplying a liquid phase to move the fluid, which are connected in a loop shape and sealed inside. A loop type heat pipe of a fluid such as ethanol.

In the circuit type heat pipe 1, as shown in Fig. 1, the evaporator 2 has a porous body 6, and the operating fluid can be circulated by the capillary force of the porous body 6 to transfer heat.

That is, here, the evaporator 2 is a CPU 51X that is thermally connected as a heat generating component. For example, the evaporator 2 is adhered to the CPU 51X provided on the wiring substrate 52 through the thermal conductive paste 56, and heat from the CPU 51X is transmitted to the evaporator 2.

Thereby, part of the liquid phase actuating fluid supplied to the evaporator 2 is oozing out from the surface of the porous body 6 provided on the evaporator 2, and the liquid phase actuating fluid which oozes from the surface of the porous body 6 is acted upon by The heat generated by the CPU 51X of the heat generating component evaporates (vaporizes) and becomes a gas phase actuating fluid.

This gas phase actuating fluid flows into the condenser 3 through the vapor tube 4 as shown in FIG. Thereby, the heat absorbed in the evaporator 2 is sent to the condenser 3.

Further, the gas phase actuating fluid flowing into the condenser 3 is condensed (liquefied) by cooling in the condenser 3 to become a liquid phase actuating fluid. Thereby, the heat sent to the condenser 3 dissipates heat. Here, the condenser 3 is disposed in the vicinity of the blower fan 53, and the condenser 3 is provided with a heat dissipating fan 57. Further, the heat sent to the condenser 3 is radiated by the heat radiating fan 57, and is released to the outside of the casing 50 by the air blow from the blower fan 53.

Furthermore, other heat dissipating members such as heat sinks may be provided instead. Cooling fan 57. Further, instead of providing a heat dissipating member, the pipe member may be directly supplied with air to cool. Here, although cooling is performed by an air-cooling type cooling means, it may be cooled by a water-cooling type cooling means.

This liquid phase actuating fluid flows into the evaporator 2 via the liquid pipe 5.

Thus, the actuating fluid circulates in a circulation path composed of the evaporator 2, the vapor tube 4, the condenser 3, and the liquid tube 5.

In particular, in the present embodiment, the evaporator 2 is configured as follows.

Here, the evaporator 2 will be described as an example of a thin flat evaporator which is suitable for efficiently cooling a flat type heat generating body (here, a CPU 51X as a heat generating component). Further, the thin flat evaporator is also referred to as a thin evaporator or a flat evaporator.

As shown in Fig. 1 and Fig. 2, the evaporator 2 of the present embodiment has a porous body (a capillary structure made of a porous material) 6, a vapor chamber 7 and a liquid chamber 8 partitioned by a porous body 6, The housing 9 and the mask 10.

Here, the porous body 6 is a porous body having a low thermal conductivity. Specifically, it is a porous PTFE (polytetrafluoroethylene) resin molded body (a porous body made of a resin).

In particular, in the present embodiment, the porous body 6 has a plurality of cylindrical convex portions 6A. That is, the porous body 6 has a plate-like portion 6B and a plurality of cylindrical convex portions 6A provided on the flat plate portion 6B. Here, the plurality of cylindrical convex portions 6A are provided so as to protrude from the liquid chamber 8 side (that is, the upper side portion 9B side of the casing 9) to the flat portion 6B, respectively, on the side of the vapor chamber 7 (that is, a casing to be described later) The lower side portion 9A side 9 has an insertion hole 6C into which the projection 9C provided at the lower side portion 9A of the casing 9 is inserted. Moreover, it is provided on the side of the insertion hole 6C. There are a plurality of grooves 6D extending in the depth direction thereof.

The casing 9 has a portion (first portion) 9A that connects the steam pipe 4 and defines a lower portion of the vapor chamber 7, and a connecting liquid pipe 5 and defines an upper portion (second portion) 9B of the liquid chamber 8.

In other words, the vapor tube connection opening portion 9D (the outlet of the evaporator 2) is provided in the lower side portion 9A of the casing 9, and the vapor tube 4 is connected to the vapor tube connection opening portion 9D. In this manner, the vapor tube 4 is connected to the vapor chamber 7 defined by the lower portion 9A of the casing 9 constituting the evaporator 2. Here, the lower side portion 9A of the casing 9 is constituted by the bottom plate 9AX having the recessed portion 9AY, and the steam pipe 4 is connected to the steam pipe connecting opening portion 9D provided in the bottom plate 9AX.

Further, a liquid pipe connecting opening portion 9E (an inlet of the evaporator 2) is provided in the upper side portion 9B of the casing 9, and a liquid pipe 5 is connected to the liquid pipe connecting opening portion 9E. In this manner, the liquid pipe 5 is connected to the liquid chamber 8 defined by the upper portion 9B of the casing 9 constituting the evaporator 2. Here, the upper side portion 9B of the casing 9 is constituted by the frame body 9BX and the lid body 9BY, and the liquid pipe 5 is connected to the liquid pipe connection opening portion 9E provided in the frame body 9BX.

Here, although the vapor tube 4 and the liquid tube 5 are connected to one side of the casing 9, the present invention is not limited thereto. For example, the liquid pipe 5 may be connected to one side of the casing 9, and The other side is connected to the vapor tube 4.

Further, the lower side portion 9A of the casing 9 is thermally connected to the CPU 51X as a heat generating component. Thereby, the vapor chamber 7 defined by the lower side portion 9A of the casing 9 is disposed at a position close to the CPU 51X, and the liquid chamber 8 defined by the upper side portion 9B of the casing 9 is disposed at a position far from the CPU 51X. Further, the thermal conductivity of the upper side portion 9B of the casing 9 is made lower than that of the lower side portion 9A. For example, as will be described later, The upper side portion 9B of the casing 9 is made of stainless steel, so that the lower side portion 9A of the casing 9 is made of copper as long as the thermal conductivity of the upper side portion 9B of the casing 9 is lower than that of the lower side portion 9A. Thereby, the heat of the CPU 51X, which is a heat generating component, is difficult to be transmitted to the liquid phase actuating fluid, and the temperature of the liquid phase actuating fluid is hard to rise.

Further, the casing 9 is provided on the lower side portion 9A and protrudes to the side of the upper side portion 9B, and has a plurality of projections 9C that are fitted into each of the plurality of cylindrical projections 6A of the porous body 6. That is, the lower side portion 9A of the casing 9 is provided with a plurality of projections 9C projecting to the side of the upper side portion 9B, and the plurality of projections 9C are embedded in a plurality of cylindrical projections provided in the porous body 6. The insertion hole 6C of each of the portions 6A. Here, a plurality of protrusions 9C are integrally formed on the surface of the recess 9AY of the bottom plate 9AX constituting the lower side portion 9A of the casing 9. Further, a plurality of projections 9C are fitted into the insertion holes 6C provided in each of the plurality of cylindrical projections 6A of the porous body 6, so that the central axis of the projections 9C and the center of the cylindrical projections 6A of the porous body 6 are formed. The axes (i.e., the central axes of the insertion holes 6C) are identical.

In this manner, the porous body 6 is housed in the casing 9. In particular, a plurality of projections 9C are fitted into each of the plurality of cylindrical projections 6A of the porous body 6, and on the back surface of the porous body 6 (lower side in Fig. 1) and the surface of the lower side portion 9A of the casing 9 ( In Fig. 1, a space is formed between the upper ones. Thereby, a space formed between the back surface of the porous body 6 and the surface of the lower side portion 9A of the casing 9 serves as the vapor chamber 7. Here, a plurality of grooves 6D are formed on the side faces of the insertion holes 6C provided in each of the plurality of cylindrical convex portions 6A of the porous body 6, and are formed in the space between the grooves 6D, that is, formed in the insertion holes. The bottom surface of 6D groove 6D The space between the side faces of the protrusions 9C also constitutes a part of the vapor chamber 7. On the other hand, a space formed between the surface of the porous body 6 (the upper surface in Fig. 1) and the surface (the lower surface in Fig. 1) of the upper side portion 9B of the casing 9 becomes the liquid chamber 8. The liquid chamber 8 also has a reservoir for storing the liquid phase working fluid.

Further, the liquid-phase actuating fluid that has flowed in and stored in the liquid chamber 8 permeates from the periphery of each of the plurality of cylindrical convex portions 6A of the porous body 6 by capillary action, and oozes out toward the vapor chamber 7 side. On the other hand, when the CPU 51X which is a heat generating component generates heat, heat is transferred to the lower side portion 9A of the casing 9, and is further transmitted to each of the plurality of projections 9C. Further, by the heat transferred to each of the plurality of protrusions 9C, the liquid phase working fluid that has ooze out to the vapor chamber 7 side evaporates (vaporizes) and becomes a gas phase actuating fluid. In particular, a plurality of cylindrical convex portions 6A are provided by the porous body 6, and the evaporation area is increased to improve the cooling performance. Further, a projection portion 9C is provided in the lower side portion 9A of the casing 9, and the cylindrical projection portion 6A is fitted therein, whereby the penetration distance of the liquid phase working fluid is uniform. In this way, even if the CPU 51X of the heat generating component is increased in size, the amount of heat generation is increased, and the amount of heat generated by the heat generating body such as the amount of evaporation is increased to increase the amount of evaporation, it is also possible to prevent the liquid phase actuating fluid from being supplied to the vapor of the porous body 6. The surface on the side of the chamber 7 (i.e., the end on the heating surface side) can prevent the occurrence of dryness, a reduction in evaporation area, and a markedly lowered cooling performance. In the porous body 6 in which the cylindrical convex portion 6A is provided and the evaporation area is enlarged, the thickness is uniform, and the porous body 6 of the contact protrusion portion 9C is uniform in the wet state, and the porous body is expanded from the evaporation area. 6 Efficiently evaporates the liquid phase working fluid to obtain stable cooling performance.

Further, as described above, the protrusion is provided as the lower side portion 9A of the casing 9 9C, when the cylindrical convex portion 6A is fitted therein, and a space in which the liquid phase fluid flows is formed around the respective projections 9C of the cylindrical convex portion 6A, as shown in FIGS. 4(A) and 4(B). It is shown that the area of the liquid contact surface 6X where the liquid phase working fluid 11 of the porous body 6 contacts is increased. Further, when the area of the liquid contact surface 6X where the liquid phase working fluid 11 of the porous body 6 contacts is increased, heat leakage from the porous body 6 to the liquid phase working fluid 11 is increased, and the cooling performance is lowered. Further, in FIGS. 4(A) and 4(B), the arrow symbol indicated by the symbol X indicates the flow of heat, and the arrow symbol indicated by the symbol Y indicates the flow of the liquid phase actuating fluid.

In other words, in the above-described loop type heat pipe 1, in order to improve the cooling performance, the projection portion 9C is provided in the lower side portion 9A of the casing 9 thermally connected to the CPU 51X as a heat generating component, and is embedded in the cylinder of the porous body 6 The convex portion 6A expands the evaporation area. In this case, the molten surface 6Y of the protrusion 9C which is the high temperature of the cylindrical convex portion 6A of the porous body 6 is in contact with the cylindrical convex portion 6A of the porous body 6 in contact with the low-temperature liquid phase working fluid 11 Since the liquid contact surface 6X is integrated in the front and back, when the area of the evaporation surface 6Y of the porous body 6 is enlarged as described above, the area of the liquid contact surface 6X is further enlarged.

Here, the heat transfer from the porous body 6 to the liquid phase working fluid 11 is expressed by the following formula.

[Number 1] Q = hA ( T _W - T _L )

Here, Q is the heat leakage heat from the porous body 6 to the liquid phase working fluid 11, h is the heat transfer coefficient, and A is the contact area (the liquid contact area) of the porous body 6 and the liquid phase working fluid 11, T _W It is the surface temperature of the porous body 6, and TL is the temperature of the liquid phase working fluid 11.

Therefore, the heat leakage heat Q from the porous body 6 to the liquid phase working fluid 11 is increased by the expansion of the liquid contact area A.

Further, by increasing the liquid contact area A, the surface temperature T _{W of the} porous body 6 rises. This is because the liquid contact area A of the porous body 6 is enlarged, and the flow velocity of the liquid phase working fluid 11 flowing into the liquid contact surface 6X of the porous body 6 is lowered (see FIG. 5(A)). Here, the flow velocity of the liquid phase working fluid 11 flowing into the porous body 6 is based on the type of the working fluid or the amount of heat generated, but is approximately several tens of μm/sec to several hundreds μm/sec, which affects the heat conduction in the porous body 6. Very big. When the inflow velocity to the liquid contact surface 6X of the porous body 6 is fast, the heat (heat leakage) entering the porous body 6 will flow back, but if the inflow velocity is slow, it enters the porous body 6 by heat conduction. The heat is increased, and the heat leakage to the side of the liquid phase working fluid 11 is increased. As described above, when the liquid contact area of the porous body 6 is enlarged, not only the heat exchange area (A) is increased, but also the temperature (T _W ) of the heat exchange surface is increased, so that the heat leakage becomes extremely large.

Further, the operating fluid inside the loop type heat pipe 1 is kept in a saturated state, and the fluid is actuated by a vapor pressure difference caused by a temperature difference between the vapor side and the liquid side separated by the porous body 6 in the evaporator 2. Therefore, when the heat of heat transfer from the vapor side of the evaporator 2 to the liquid side via the porous body 6 is large, the loop type heat pipe 1 produces a significant performance degradation.

Therefore, in order to remove the cause of the performance degradation of the loop type heat pipe 1, a loop type heat pipe 1 having high cooling performance and an electronic device having the same are realized.

Therefore, in the present embodiment, as shown in FIGS. 1 and 2, a plurality of masks 10 for covering the respective surfaces of the plurality of cylindrical projections 6A are provided, The area of the liquid contact surface 6X that contacts the liquid phase working fluid 11 of the plurality of cylindrical convex portions 6A of the porous body 6 is reduced. By providing the mask 10, the area (passing area) when the liquid-phase operating fluid 11 flows into the surface of the cylindrical convex portion 6A of the porous body 6 and contacts the liquid contact surface 6X of the liquid-phase fluid 11 is reduced. By providing the mask 10, the liquid contact surface 6X of the cylindrical convex portion 6A of the porous body 6 is made small, and the area in which the liquid-phase working fluid 11 and the porous body 6 are in direct contact with each other can be reduced, and the inflow can be improved. The flow rate of the liquid phase operating fluid 11 of the porous body 6. By the multiplication effect, the amount of heat transfer from the porous body 6 to the liquid phase working fluid 11 can be reduced, and heat leakage from the porous body 6 to the liquid phase working fluid 11 can be reduced, and the evaporator 2 can be improved. The cooling efficiency further increases the cooling capacity of the loop heat pipe 1.

For example, the mask 10 may be formed to have an opening 10A through which the liquid-phase operating fluid 11 flows in a portion covering the side surface of the cylindrical convex portion 6A. In this case, the surface of the cylindrical convex portion 6A of the porous body 6 is covered by the mask 10, and only the portion of the opening 10A of the mask 10 on the side surface of the cylindrical convex portion 6A of the porous body 6 is located. The liquid contact surface 6X has a small area of the liquid contact surface 6X of the cylindrical convex portion 6A of the porous body 6.

Here, the opening 10A may be formed as a plurality of holes 10B.

Preferably, the holes 10B include a full extent of the covering portion and are uniformly disposed on the side of the cylindrical projection 6A of the mask 10.

Further, as shown in Fig. 7, the holes 10B are preferably larger than the front end side of the cylindrical convex portion 6A of the porous body 6, and the flat portion 6B side. That is, it is preferable that the holes 10B are larger on the side of the lower side portion (first portion) 9A than on the side of the upper side portion (second portion) 9B of the casing 9. This is because the lower side The side of the vapor chamber 7 defined by the portion 9A is higher than the liquid chamber 8 side defined by the upper portion 9B of the casing 9, and the amount of evaporation is large. Thus, by reducing the size distribution of the pores 10B and reducing the area (the liquid contact area) where the porous body 6 is in direct contact with the liquid phase working fluid 11, the flow velocity of the liquid phase working fluid 11 flowing into the porous body 6 can be uniformly increased. The heat leakage from the porous body 6 to the liquid phase working fluid 11 can be similarly reduced.

Here, the shape of the hole 10B is circular, but it is not limited thereto, and various shapes such as a triangle or a quadrangle may be formed.

Further, as shown in FIG. 11, the opening 10A may be a plurality of slits 10C.

The slits 10C are preferably formed to include side faces of the cylindrical projections 6A in which the masks 10 are integrally and uniformly provided.

Further, it is preferable that the slits 10C have a wider width on the front end side than the cylindrical convex portion 6A of the porous body 6 on the side of the flat portion 6B. That is, it is preferable that the slits 10C have a width wider than a side located on the lower side portion (first portion) 9A and a side closer to the upper side portion (second portion) 9B of the casing 9. This is because the vapor chamber 7 side defined by the lower portion 9A is higher in temperature than the liquid chamber 8 side defined by the upper portion 9B of the casing 9, and the amount of evaporation is large. Thus, by changing the extent of the slit 10C, the area (the liquid contact area) where the porous body 6 is in direct contact with the liquid phase working fluid 11 can be reduced, and the flow rate of the liquid phase working fluid 11 flowing into the porous body 6 can be uniformly made. The increase and the heat leakage from the porous body 6 to the liquid phase actuating fluid 11 can be similarly reduced.

Here, the slit 10C is formed to extend in the height direction of the cylindrical convex portion 6A, but is not limited thereto, and may be, for example, a cylindrical shape. The convex portion 6A extends in the circumferential direction. In addition, when the slit 10C extending in the height direction of the cylindrical convex portion 6A is formed, it can be modeled in consideration of mass production and cost reduction. Therefore, as shown in Fig. 12, it is preferable to extend the slit 10C to the lower end. And the cut from the lower end.

In these cases, the mask 10 is preferably provided with the opening 10A such that the area of the liquid contact surface 6X on the side surface of the cylindrical convex portion 6A is 50% or less of the area of the side surface of the cylindrical convex portion 6A. In this case, the area (opening area) of the opening 10A of the mask 10 is 50% or less of the area of the portion covering the side surface of the cylindrical convex portion 6A of the mask 10. In other words, the portion covering the side surface of the cylindrical convex portion 6A of the mask 10 is composed of the opening portion 10A (the portion where the porous body 6 is in contact with the liquid phase working fluid 11) and the portion other than the opening portion 10A (the porous body 6). The portion that is in contact with the mask 10 is configured such that the area of the opening 10A is equal to or smaller than the area of the portion other than the opening 10A. Thus, the ratio of the opening portion 10A in the covering portion of the side surface of the cylindrical convex portion 6A covering the mask 10, that is, the opening ratio of the mask 10 is preferably 50% or less. As described above, the area of the liquid contact surface 6X on the side surface of the cylindrical convex portion 6A of the porous body 6 is preferably 50% or less as compared with the case where the mask 10 is not provided. Thereby, the area in which the liquid phase working fluid 11 (actuating liquid) is in direct contact with the porous body 6 can be reduced to 1/2 or less, and the flow rate of the liquid phase working fluid 11 to the porous body 6 can be increased to More than 2 times.

Further, the larger the area of the liquid contact surface 6X of the cylindrical convex portion 6A, the lower the aperture ratio of the mask 10 is required, and in the case of a specific configuration example to be described later, for example, the aperture ratio of the mask 10 is preferably about 35%. Or below.

Further, the size of the plurality of holes 10B or the slits 10C as the opening portion 10A is set to be on the side of the lower side portion (first portion) 9A (the cylindrical convex portion 6A) The base side; the vapor chamber 7 side; the high temperature side of the protrusion 9C is located on the side of the upper side portion (second portion) 9B of the casing 9 (the front end side of the cylindrical convex portion 6A; the liquid chamber 8 side; the projection portion 9C) When the low temperature side is large, the side of the lower portion (first portion) 9A of the opening ratio of the mask 10 is higher than the side of the upper portion (second portion) 9B of the casing 9. In this case, the average aperture ratio of the mask 10 may be 50% or less. As long as the aperture ratio of the mask 10 is distributed as follows: for example, on the side of the lower side portion (first portion) 9A of the casing 9, the aperture ratio of the mask 10 is 55%, and the mask is formed near the center. The aperture ratio of 10 is 35%, and the aperture ratio of the mask 10 is 15% on the side of the upper side portion (second portion) 9B of the casing 9, and the average aperture ratio of the mask 10 is 50% or less.

Here, the mask 10 is a cylindrical mask having the opening 10A and is covered by the cylindrical convex portion 6A of the porous body 6, but the invention is not limited thereto.

For example, as shown in FIG. 13 and FIG. 14, the mask 10 has a first portion 101 partially covering the side surface of the first cylindrical convex portion 61A included in the adjacent four cylindrical convex portions 6A; The second portion 102 on the side surface of the second cylindrical convex portion 62A included in each of the cylindrical convex portions 6A; and the third portion covering the side surface of the third cylindrical convex portion 63A included in the four cylindrical convex portions 6A And a part of the fourth portion 104 covering the side surface of the fourth cylindrical convex portion 64A included in the four cylindrical convex portions 6A is disposed one by one in the adjacent four masks 10-1 to 10-4. Each of the four portions 101-1 to 101-4 may cover the side surface of one of the cylindrical convex portions 61A, and the liquid-phase operating fluid 11 flows between the four portions 101-1 to 101-4. Slot 10D.

In this case, the mask 10 has: the first part 101 to the fourth part The portion 104 and the plate portion 105 supporting the first portion 101 to the fourth portion 104 are inserted into a region surrounded by the adjacent four cylindrical convex portions 6A (61A to 64A).

According to this configuration, the mask 10 can be provided even if the gap between the cylindrical convex portions 6A is narrow.

The evaporator 2 in which the mask 10 thus constructed is disposed is as shown in FIG.

Further, in Figs. 13 and 14, the respective portions 101 to 104 of the mask 10 are integrated, and a flow path 10E through which the liquid phase working fluid 11 flows is provided at the center portion. However, the present invention is not limited thereto, and the respective portions 101 to 104 of the mask 10 may be separated from each other, and the central region surrounded by the respective portions 101 to 104 may be a flow path through which the liquid phase working fluid 11 flows.

In this case as well as the slit 10C as the opening 10A described above, the slit 10D is preferably provided uniformly and uniformly for the portion including the side surface of the cylindrical convex portion 6A covering the mask 10. Further, the slit 10D is preferably such that the side of the lower portion (first portion) 9A is wider than the side of the upper portion (second portion) 9B of the casing 9. Further, the mask 10 is preferably provided with a slit 10D such that the area of the liquid contact surface 6X on the side surface of the cylindrical convex portion 6A is 50% or less of the area of the side surface of the cylindrical convex portion 6A.

Further, for example, as shown in FIGS. 16(A) and 16(B), the mask 10 may be formed as a groove 10F having a portion in which the liquid phase working fluid 11 flows on the side surface covering the cylindrical convex portion 6A. In this case, it is only necessary to provide a plurality of grooves 10F. Further, similarly to the hole 10B or the slit 10C as the above-described opening portion 10A, the grooves 10F are preferably provided integrally and uniformly including a portion including the side surface of the cylindrical convex portion 6A covering the mask 10. Moreover, the grooves 10F should be the lower side The side of the minute (first part) 9A is wider than the side of the upper side portion (second portion) 9B of the casing 9. Further, the mask 10 is preferably provided with a groove 10F such that the area of the liquid contact surface 6X on the side surface of the cylindrical convex portion 6A is 50% or less of the area of the side surface of the cylindrical convex portion 6A.

Here, the mask 10 has the protrusion 10G at its end surface, and is inserted into a region surrounded by the adjacent four cylindrical protrusions 6A so that the protrusion 10G is below, thereby being in the flat portion of the porous body 6. A gap is formed between 6B. This is because the side of the flat portion 6B of the porous body 6 is at a high temperature, and the amount of evaporation is increased. Therefore, the liquid phase working fluid 11 is easily supplied thereto.

Further, in FIGS. 16(A) and 16(B), the mask 10 is inserted into a region surrounded by the adjacent four cylindrical convex portions 6A. However, the present invention is not limited thereto, and may be formed on the outer peripheral surface. A cylindrical mask having a groove 10F through which the liquid phase working fluid 11 flows is applied to the cylindrical convex portion 6A.

Further, as described above, the hole 10B, the slits 10C, 10D, and the groove 10F are provided integrally and uniformly including the portion covering the side surface of the cylindrical projection 6A of the mask 10, whereby the liquid-phase actuating fluid 11 can be shortened. The distance within the body 6 is moved and the pressure loss can be reduced.

Further, as shown in FIG. 9, the mask 10 may be a porous body mask 10H having pores (fine pores) through which the liquid phase working fluid 11 flows. In this case, the porous body mask 10H is preferably a porosity of 50% or less. In addition, as the area of the liquid contact surface 6X of the cylindrical convex portion 6A is larger, it is preferable to use a porosity having a lower porosity. For a specific configuration example to be described later, for example, a porosity of about 35% or less is preferably used. . Further, it is preferable that the porous body mask 10H has a larger diameter of the hole to reduce the pressure loss. For example, the porous body mask 10H should be the diameter of the hole (more The pore diameter; pore diameter) is larger than that of the porous body 6 (capillary structure). This is because, in order to obtain the capillary force, the diameter of the porous body 6 as the capillary structure is preferably smaller. In order to reduce the flow resistance, the fluidity is better, and the porous body mask 10H should preferably use a hole. The larger diameter is the reason. For example, when a porous PTFE resin molded body (a porous resin body) is used for the porous body 6, the porous body cover 10H is made of a porous PTFE resin molded body having a larger porous diameter (resin made of resin). The porous body can be used. Specifically, the porous body mask 10H preferably has a diameter of 50 μm or more.

Further, the plurality of masks 10 are, for example, as shown in Fig. 17, and are preferably integrated. Thereby, the number of parts can be reduced and the cost can be reduced. Here, although the mask 10 shown in FIG. 13 is exemplified as an integrator, the present invention is not limited thereto, and the other masks 10 described above may be integrated.

Further, the material of the mask 10 is a material having a low thermal conductivity. When a PTFE resin is used, for example, the thermal conductivity is about 0.2 to about 0.3 W/mK. That is, the material of the mask 10 is a material (resin material) having a thermal conductivity of 0.5 W/mK or less. For example, the material of the mask 10 is preferably a material having a lower thermal conductivity than the liquid phase operating fluid 11. Here, when the liquid phase operating fluid 11 is water, since the thermal conductivity is about 0.6 W/mK, the material of the mask 10 is preferably a material having a thermal conductivity lower than 0.6 W/mK. Further, for example, when the liquid phase operating fluid 11 is ethanol or acetone, since the thermal conductivity is about 0.2 W/mK, the material of the mask 10 is preferably a material having a thermal conductivity of less than about 0.2 W/mK.

Therefore, according to the evaporator, the cooling device, and the electronic device of the present embodiment, heat leakage from the porous body 6 to the liquid phase working fluid 11 is reduced. There is an advantage that the reduction in cooling performance can be suppressed and the cooling performance of stability can be obtained. In other words, the cooling performance of the loop heat pipe 1 can be greatly improved, and the heat generating components provided in the electronic device can be cooled stably, and the electronic device can be improved in performance and reliability can be improved.

Hereinafter, a specific configuration example of the loop type heat pipe of the cooling device 1 of the present embodiment will be described.

First, the evaporator 2 has an outer dimension of about 75 mm x about 75 mm and a height of about 25 mm. Since the lower side portion 9A of the casing 9 of the evaporator 2 is thermally connected to the heating element 51X, it is made of copper having a high thermal conductivity, and the upper side portion 9B of the casing 9 is made of stainless steel having a relatively low thermal conductivity. Thereby, heat from the heat generating body 51X is hard to be transferred to the liquid phase actuating fluid via the lower side portion 9A of the casing 9. Further, here, non-porous PTFE (polytetrafluoroethylene) is attached to the inner wall surface of the upper side portion 9B of the casing 9, that is, the wall surface of the liquid chamber 8 which is in direct contact with the liquid phase working fluid, and is insulated from the casing 9 The upper side portion 9B leaks heat to the liquid phase working fluid.

Further, in order to mount the porous body 6, a bottom surface (copper bottom portion) of the lower side portion 9A of the casing 9 is provided with six projections in the longitudinal direction, six in the horizontal direction, and arranged in a lattice shape, and a total of 36 projections (cylindrical; convex portions; The copper pin 9C (see Fig. 2) has a size of each of the projections 9C of a diameter (outer diameter) φ of about 5 mm and a height of about 15 mm.

The porous body 6 is a molded article using a mold. Here, a porous PTFE (polytetrafluoroethylene) resin molded body having a porosity of about 40% and an average value of a porous diameter of about 10 μm is used. Platinum). The porous body 6 is provided with six cylinders in the longitudinal direction, six in the lateral direction, and arranged in a lattice shape and a total of 36 cylinders. Concave convex portion (cylindrical convex portion) 6A. The cylindrical convex portions 6A have a size of about 9 mm in outer diameter φ and about 7 mm in inner diameter φ. The central axis of the cylindrical convex portion 6A, that is, the central axis of the insertion hole 6C provided on the back side of the cylindrical convex portion 6A, and the respective projections 9C provided at the lower side portion 9A of the casing 9 are respectively provided. The center axis is consistent. Further, the insertion holes 6C provided on the back side of the cylindrical convex portions 6A are respectively inserted into the respective projections 9C provided on the bottom surface of the lower side portion 9A of the casing 9, and the porous body 6 is attached to the casing. 9 lower side part (refer to Fig. 1, Fig. 2).

Here, the depth of the insertion hole 6C provided on the back side of the cylindrical convex portion 6A is about 13 mm. Thereby, the insertion holes 6C provided on the back side of the cylindrical convex portions 6A are respectively inserted into the respective projections 9C provided on the bottom surface of the lower side portion 9A of the casing 9, and the porous body 6 is attached to the casing. The lower surface portion 9A of the body 9 has the bottom surface of the casing 9 (i.e., the bottom surface of the lower side portion 9A of the casing 9) and the back surface of the porous body 6 (i.e., the back surface of the flat portion 6B of the porous body 6). A space of about 2 mm is formed between them as a vapor chamber 7 (refer to Fig. 1).

Further, the diameter of the insertion hole 6C provided on the back side of the cylindrical convex portion 6A is smaller than the outer diameter of the projection 9C of the casing 9 by about 50 μm to about 200 μm. Thereby, when the porous body 6 is attached to the lower side portion 9A of the casing 9, sufficient adhesion can be obtained.

Further, on the side surface (inner wall) of the insertion hole 6C, a groove (groove) 6D extending in the depth direction (vertical direction) having an amplitude of about 1 mm, a depth of about 1 mm, and a pitch of about 2 mm is uniformly provided (refer to Figs. 1 and 2). ). Thereby, a space formed between the grooves 6D, that is, a bottom surface of the groove 6D formed on the side of the insertion hole 6C is The space between the side faces of the projections 9C of the casing 9 also functions as a part of the steam chamber 7. Thus, the side surface of the insertion hole 6C serves as a fin structure, and the tip end of the fin is adhered to the side surface of the projection 9C of the casing 9. Further, the liquid-phase working fluid 11 supplied from above the porous body 6 passes through the inside of the cylindrical convex portion 6A of the porous body 6, and is provided on the side surface of the insertion hole 6C, and is in contact with the projection 9C of the casing 9. The front end of the fin is evaporated and vaporized, and the vapor generated at the tip end of the fin flows downward in the groove between the fins, and reaches the vapor tube 4 through the space between the back surface of the porous body 6 and the bottom surface of the casing 9.

Further, the lower side portion 9A of the casing 9 to which the porous body 6 is attached is coupled to the upper side portion 9B of the casing 9, and the porous body 6 is housed in the casing 9 in a state where the porous body 6 is detached. An inner space of a height of about 5 mm is formed between the upper surface of the cylindrical convex portion 6A of the porous body 6 and the lower surface of the upper side portion 9B of the casing 9, and the inner space and the plurality of cylindrical convex portions of the porous body 6 are formed. The space between 6A serves as a liquid chamber 8 having a liquid storage tank (see Fig. 1).

The vapor chamber 7 of the evaporator 2 thus produced (that is, the lower portion 9A of the casing 9 defining the vapor chamber 7 of the evaporator 2) is connected to the inlet of the condenser 3 by a vapor tube 4 (refer to Fig. 3). Further, the liquid chamber 8 of the evaporator 2 (that is, the upper portion 9B of the casing 9 defining the liquid chamber 8 of the evaporator 2) is connected to the outlet of the condenser 3 by a liquid pipe 5 (see Fig. 3).

Here, the vapor tube 4 is a copper tube having an outer diameter of about 6 mm and an inner diameter of about 5 mm, and has a length of about 300 mm. Further, the liquid pipe 5 is a copper pipe having an outer diameter of about 4 mm and an inner diameter of about 3 mm, and has a length of about 200 mm. Further, the condenser 3 has a size of about 150 mm, a height of about 50 mm, and a length of about 45 mm. Here, the aluminum flat fin (heat radiating fan 57) is attached to the condensing duct provided in the condenser 3 (see FIG. 3). The condensing tube uses a copper grooved tube having an outer diameter of about 6.35 mm, and the aluminum flat plate fin 57 has a thickness of about 0.2 mm and a pitch of about 1.5 mm.

Further, the actuating fluid is ethanol, and after the internal vacuum of the loop type heat pipe 1 is evacuated by a vacuum pump to be in a vacuum state, a predetermined amount of ethanol which has been vacuum defoamed in a saturated state is sealed and sealed.

Further, in the case of the evaporator 2 having the above configuration, in order to improve the cooling performance, as shown in Fig. 5(A), a projection 9C (pin configuration) is provided on the bottom surface of the lower side portion 9A of the casing 9, and Since the cylindrical convex portion 6A of the porous body 6 is fitted and the evaporation area is enlarged, the area of the liquid contact surface 6X integrated with the surface of the evaporation surface 6Y is also enlarged. Therefore, the heat exchange area between the porous body 6 and the liquid phase working fluid 11 is large, and the flow velocity of the liquid phase working fluid 11 flowing into the porous body 6 is also large, so that the heat of the fluid 11 is driven from the porous body 6 to the liquid phase. The leak is very large. Due to this influence, the temperature (liquid temperature) of the liquid working fluid 11 above the porous body 6 rises, and the temperature of the liquid phase working fluid 11 supplied to the porous body 6 becomes high, and the liquid phase working fluid 11 evaporates. The temperature of the gasified gas phase actuating fluid also becomes high. Therefore, the temperature of the casing 9 having the projections 9C is also high, and the CPU 51X as a heat generating component cannot be sufficiently cooled.

Therefore, as a first specific example, in order to prevent the heat flow from the porous body 6 to the liquid phase working fluid 11, a mask 10 having a hole 10B having a diameter of about 1 mm uniformly provided on the side surface is provided (capillary structure mask; heat insulation) In the mask, the opening ratio of each of the cylindrical convex portions 6C of the porous body 6 described above is about 35% [see FIGS. 1 , 2 , and 5 (B)].

Here, the mask 10 uses a PTFE resin (non-porous body) having a low thermal conductivity (here, about 0.23 W/mK) and excellent heat resistance, And the thickness is about 0.8 mm. By providing the mask 10, the area (the liquid receiving area) of the porous body 6 in direct contact with the liquid phase working fluid 11 can be reduced by about 35%, and the flow rate of the liquid phase working fluid 11 flowing into the porous body 6 can be increased by about 3 Times.

Next, an experiment of cooling the heater which is a heater for molding the heat generating component 51X in the electronic device using the loop type heat pipe 1 having the evaporator 2 provided with such a mask 10 is performed. Further, for comparison, a cooling experiment using a loop type heat pipe having an evaporator without a mask was also performed.

Here, FIG. 6(A) shows the results of performing the cooling experiments and measuring the heater temperature, that is, the evaporator bottom surface temperature (case bottom temperature).

Further, in Fig. 6(A), the solid line A is a temperature indicating the bottom surface of the evaporator 2, and the evaporator is used to cool the heater using the loop type heat pipe 1 having the evaporator 2 provided with the mask 10 as described above. The heaters are connected. Further, in Fig. 6(A), the solid line B is a temperature indicating the bottom surface of the evaporator, and the evaporator is connected to a heater when a loop type heat pipe cooling heater having an evaporator having no mask is provided.

As shown in Fig. 6(A), when the loop type heat pipe 1 having the evaporator 2 provided with the above-described mask 10 is used, a circuit having an evaporator having no mask is used in all of the calorific value. In the case of a heat pipe, the evaporator bottom temperature, that is, the heater temperature, can be reduced by about 10 ° C before and after.

Further, since it is considered that the temperature of the upper surface of the evaporator 2 having the liquid storage tank reflects the temperature of the liquid phase operating fluid 11, the temperature above the evaporator 2 is measured. (The temperature above the casing) also obtained the measurement result as shown in Fig. 6 (B).

Further, in Fig. 6(B), the solid line A shows the upper surface temperature of the evaporator 2 when the heater is cooled using the loop type heat pipe 1 having the evaporator 2 provided with the mask 10 as described above. Further, in Fig. 6(B), the solid line B is the upper surface temperature of the evaporator when the loop type heat pipe cooling heater having the evaporator without the mask is used.

As shown in Fig. 6(B), when the loop type heat pipe 1 having the evaporator 2 provided with the above-described mask 10 is used, among all the calorific values, an evaporator having no mask is used as compared with the case where the evaporator is provided In the case of a loop type heat pipe, the temperature above the evaporator is about 5 to about 8 ° C, which means that the temperature of the liquid phase actuating fluid 11 is reduced.

Thus, by using the loop type heat pipe 1 having the evaporator 2 provided with the mask 10 as described above, it can be confirmed that the temperature of the liquid phase actuating fluid 11 is reduced, and the flow of the fluid 11 from the porous body 6 to the liquid phase can be reduced. Heat leaks. Further, it was confirmed that the heater temperature can be reduced, the cooling performance can be suppressed from being lowered, and the cooling performance can be stabilized.

Further, in the second specific example, the cylindrical convex portion 6A of the porous body 6 is provided, and the hole 10B having a diameter of about 0.5 mm to about 1.5 mm is provided on the side surface so that the opening ratio is about 35% on average. That is, the mask 10 (capillary structure mask; heat insulating mask) (see FIG. 7) having the aperture ratio distribution is provided to prevent the heat flow from the porous body 6 to the liquid phase.

Here, the mask 10 uses a PTFE resin (non-porous body) having a low thermal conductivity (here, about 0.23 W/mK) and excellent heat resistance, and has a thickness of about 0.8 mm. Also, due to the projection 9C (copper pin) of the housing 9 Since the temperature is higher in the base portion and the front end portion is lower, it is presumed that the evaporation amount is larger in the base portion of the projection portion 9C and less in the front end portion. Therefore, the opening ratio of the mask 10 is 55% (opening diameter: about 1.5 mm) on the side of the base of the projection 9C of the casing 9, and the opening ratio of the mask 10 is 35% (opening diameter) near the center. 1.0 mm), the side of the front end of the projection 9C of the casing 9 has an opening ratio of 15% (opening diameter of about 0.5 mm), and the average opening ratio of the mask 10 is about 35%. The height direction distribution of the protrusions 9C holds the aperture ratio of the mask 10. By providing the mask, the area (the liquid-collecting area) in which the porous body 6 is in direct contact with the liquid-phase fluid 1 can be reduced by about 35%, and the flow rate of the liquid-phase fluid 11 flowing into the porous body 6 can be uniformly. Increase to about 3 times. Thus, the flow velocity of the liquid phase working fluid 11 flowing into the liquid contact surface 6X of the cylindrical convex portion 6A of the porous body 6 can be made substantially uniform in the height direction, and the fluid can be made to flow from the surface of the porous body 6 to the liquid phase. The heat leak of 11 is reduced as much in the height direction.

Further, an experiment of cooling the heater which uses a loop type heat pipe 1 having the evaporator 2 provided with such a mask 10 to mold the heat generating component 51X in the electronic device is performed. Further, for comparison, a cooling experiment using a loop type heat pipe having an evaporator without a mask was also performed.

Here, FIG. 8(A) shows the results of performing the cooling experiments and measuring the heater temperature, that is, the evaporator bottom surface temperature (the bottom surface temperature of the casing). Further, in Fig. 8(A), the solid line A shows the temperature of the bottom surface of the evaporator, which is the heater phase when cooled by the loop type heat pipe 1 using the evaporator 2 provided with the mask 10 as described above. Pick up. Also, in Figure 8(A), the solid line B is displayed. The bottom surface temperature of the evaporator is shown, which is connected to a heater when a loop type heat pipe cooling heater having an evaporator without a mask is used.

As shown in Fig. 8(A), when the loop type heat pipe 1 having the evaporator 2 provided with the above-described mask 10 is used, among all the calorific values, an evaporator having no mask is used as compared with the case where the evaporator is provided In the case of a loop heat pipe, the evaporator bottom temperature, that is, the heater temperature, can be reduced by about 12 ° C before and after.

Further, since the temperature of the upper surface of the evaporator 2 having the liquid storage tank is considered to reflect the temperature of the liquid phase working fluid 11, the temperature of the upper surface of the evaporator 2 (the temperature above the casing) is measured, as shown in Fig. 8 ( B) The measurement results shown. Further, in Fig. 8(B), the solid line A is the upper surface temperature of the evaporator when the heater is cooled using the loop type heat pipe 1 having the evaporator 2 provided with the above-described mask 10. Further, in Fig. 8(B), the solid line B shows the upper temperature of the evaporator when the heater is cooled using a loop type heat pipe having an evaporator in which no mask is provided.

As shown in Fig. 8(B), using the loop type heat pipe 1 having the evaporator 2 provided with the mask 10 as described above, in all the calorific values, evaporation with no mask is provided as compared with the use. In the case of the loop type heat pipe, the temperature above the evaporator is about 6 to about 9 ° C, which means that the temperature of the liquid phase operating fluid 11 is decreasing.

Thus, by using the loop type heat pipe 1 having the evaporator 2 provided with the mask 10 as described above, it can be confirmed that the temperature of the liquid phase working fluid 11 can be reduced, and the flow of the fluid 11 from the porous body 6 to the liquid phase can be reduced. Heat leaks. Further, it was confirmed that the temperature of the heater can be reduced, and the reduction in cooling performance can be suppressed, and the cooling performance of stability can be obtained.

Further, in the third specific example, in order to prevent the heat flow from the porous body 6 to the liquid phase working fluid 11, a porous body having a porosity of about 35% is provided in each of the cylindrical convex portions 6A of the porous body 6 described above. A mask 10H (capillary structure mask; heat insulating mask) is used as the mask 10 (refer to FIG. 9). Here, the porous body mask 10H uses a PTFE resin (porous body) having a low thermal conductivity (here, about 0.23 W/mK) and excellent heat resistance, and has a thickness of about 0.8 mm. Here, the porous body 6 having the capillary structure needs to generate a large capillary force due to the fine porous diameter in order to flow the working fluid, whereas the porous body of the mask 10 does not need to generate capillary force due to the liquid. When the phase fluid 11 passes through the mask 10, the pressure loss is small, which is advantageous for the stable operation, and therefore the porous diameter is preferably as large as possible. Therefore, here, the porous body mask 10H has a porous diameter of about 100 μm. By providing the porous body mask 10H, the area (the liquid contact area) in which the porous body 6 is in direct contact with the liquid phase working fluid 11 can be reduced to about 35%, and the liquid phase flowing into the porous body 6 can be used as the working fluid. The flow rate of 11 increased to about 3 times.

Next, an experiment of cooling the heater which molds the heat generating component 51X in the electronic device using the loop type heat pipe 1 having the evaporator 2 provided with such a mask 10H is performed. Further, for comparison, a cooling experiment using a loop type heat pipe having an evaporator without a mask was also performed.

Here, FIG. 10(A) shows the results of performing the cooling experiments and measuring the heater temperature, that is, the evaporator bottom surface temperature (the bottom surface temperature of the casing). Further, in Fig. 10(A), the solid line A is the temperature of the bottom surface of the evaporator 2, and the evaporator is used with the evaporator 2 having the mask 10H as described above. The loop type heat pipe 1 is connected to the heater of the cooling heater. Further, in Fig. 10(A), the solid line B indicates the bottom surface temperature of the evaporator which is in contact with the heater when the loop type heat pipe cooling heater having the evaporator having no mask is provided.

As shown in Fig. 10(A), in the case of the loop type heat pipe 1 having the evaporator 2 provided with the mask 10H as described above, in all the calorific values, evaporation with no mask is provided as compared with the use. In the case of the loop type heat pipe, the evaporator bottom temperature, that is, the heater temperature can be reduced by about 10 ° C before and after.

Further, since the temperature of the upper surface of the evaporator 2 (the temperature above the casing) reflecting the temperature of the liquid phase operating fluid 11 is considered, the temperature of the upper surface of the evaporator 2 is also measured as shown in Fig. 10 ( B) The measurement results shown. Further, in Fig. 10(B), the solid line A is the upper surface temperature of the evaporator 2 when the state in which the heater is cooled by the loop type heat pipe 1 having the evaporator 2 of the above-described mask 10H is used. Further, in Fig. 10(B), the solid line B is the upper surface temperature of the evaporator when the loop type heat pipe cooling heater having the evaporator having no mask is provided.

As shown in Fig. 10(B), when the loop type heat pipe 1 having the evaporator 2 provided with the mask 10H as described above is used, in all the calorific values, compared with the use of the evaporator having the mask not provided In the case of a loop type heat pipe, the temperature above the evaporator is about 5 to about 8 ° C, which means that the temperature of the liquid phase actuating fluid 11 is decreasing.

Thus, by using the loop type heat pipe 1 having the evaporator 2 provided with the above-described mask 10H, it can be confirmed that the temperature of the liquid phase actuating fluid 11 can be reduced, and the flow of the fluid 11 from the porous body 6 to the liquid phase can be reduced. Heat leaks. Further, it was confirmed that the heater temperature can be reduced, and the cooling performance can be suppressed from being lowered, and the cooling performance of stability can be obtained.

The present invention is not limited to the configuration described in the above embodiments, and various modifications can be made without departing from the spirit and scope of the invention.

2‧‧‧Evaporator

4‧‧‧Vapor tube

5‧‧‧ liquid tube

6‧‧‧Porous body

6A‧‧‧Cylindrical convex

6B‧‧‧flat part

6C‧‧‧ insertion hole

6D‧‧‧Ditch

6X‧‧‧liquid level

7‧‧ ‧ vapor room

8‧‧‧ liquid room

9‧‧‧Shell

9A‧‧‧lower part

9B‧‧‧ upper part

9C‧‧‧Protruding

9D‧‧‧ opening for steam pipe connection

9E‧‧‧ opening for liquid pipe connection

10‧‧‧ mask

10A‧‧‧ openings

10B‧‧‧ hole

11‧‧‧Liquid actuating fluid

51,51X‧‧‧Electronic parts

56‧‧‧ Thermal paste

Claims (20)

An evaporator comprising: a porous body having a plurality of cylindrical convex portions; a vapor chamber and a liquid chamber separated by the porous body; and a casing having: a steam pipe connected to the steam chamber a first portion; a second portion of the liquid chamber connected to the liquid pipe; and a plurality of protrusions provided on the first portion and protruding toward the side of the second portion, and embedded in the plurality of cylindrical bodies of the porous body Each of the convex portions and the plurality of masks cover a surface of each of the plurality of cylindrical convex portions, so that the plurality of cylindrical convex portions of the porous body contact the liquid-contacting surface of the liquid-phase fluid The area becomes smaller. The evaporator according to claim 1, wherein the portion of the mask covering the side surface of the cylindrical convex portion has an opening portion through which the liquid phase operating fluid flows. The evaporator of claim 2, wherein the opening portion is a plurality of holes. The evaporator of claim 3, wherein the hole is located on a side of the first portion of the casing and larger than a side located on the second portion. The evaporator of claim 2, wherein the opening portion is a plurality of slits. The evaporator of claim 1, wherein the mask has a first portion that partially covers a side surface of the first cylindrical convex portion included in the adjacent four cylindrical convex portions; and partially covers the four cylindrical shapes a second portion of the side surface of the second cylindrical convex portion included in the convex portion; a third portion partially covering the side surface of the third cylindrical convex portion included in the four cylindrical convex portions; and partially covering the aforementioned The fourth portion of the side surface of the fourth cylindrical convex portion included in the four cylindrical convex portions covers one of the cylindrical convex portions at four portions provided in each of the four adjacent masks On the side surface, a slit for flowing a liquid phase working fluid is formed between the four portions. The evaporator of claim 5 or 6, wherein the slit is located on a side of the first portion of the casing and has a width wider than a side of the second portion of the casing. The evaporator according to claim 2 or 5, wherein the mask is provided with the opening such that an area of the liquid receiving surface on a side surface of the cylindrical convex portion is 50% or less of an area of a side surface of the cylindrical convex portion. The evaporator of claim 6, wherein the slit is provided such that an area of the liquid contact surface on a side surface of the cylindrical convex portion is 50% or less of an area of a side surface of the cylindrical convex portion. The evaporator of claim 1, wherein the portion of the mask covering the side surface of the cylindrical convex portion has a groove for flowing the liquid phase working fluid. The evaporator of claim 10, wherein the groove is located on a side of the first portion of the casing and has a width wider than a side of the second portion. The evaporator of claim 10 or 11, wherein the mask is provided with the groove such that an area of the liquid contact surface on a side surface of the cylindrical convex portion is 50% or less of an area of a side surface of the cylindrical convex portion. An evaporator according to claim 1, wherein said mask is a porous body mask having pores for flowing said liquid phase actuating fluid. The evaporator of claim 13, wherein the porosity of the porous body mask is It is 50% or less. The evaporator of claim 13 or 14, wherein said porous body mask is such that said pore has a larger diameter than said porous body. The evaporator of claim 13 or 14, wherein the porous body mask is such that the pores have a diameter of 50 μm or more. The evaporator of any one of claims 1 to 6, 10, 11, 13, 14 wherein the material of the aforementioned mask is a material having a thermal conductivity of 0.5 W/mK or less. The evaporator of any one of claims 1 to 6, 10, 11, 13, 14 wherein the plurality of masks are integrated. A cooling device, comprising: an evaporator for evaporating a liquid phase actuating fluid; a condenser for condensing the gas phase actuating fluid; a vapor tube connecting the evaporator and the condenser and for supplying a gas phase actuating fluid; And a liquid pipe connecting the condenser and the evaporator and flowing the liquid phase to operate, the evaporator having: a porous body having a plurality of cylindrical protrusions; and a vapor chamber and a liquid chamber separated by the porous body The casing has a first portion for connecting the steam pipe and defining the steam chamber, a second portion for connecting the liquid pipe and defining the liquid chamber, and a plurality of protrusions provided in the first portion and to the second portion a side protruding, embedded in the plurality of cylindrical protrusions of the porous body And a plurality of masks covering the surfaces of the plurality of cylindrical protrusions to reduce the area of the liquid contact surface of the liquid electrolyte fluid contacting the plurality of cylindrical protrusions of the porous body . An electronic device comprising: an electronic component disposed on a wiring substrate; and a cooling device for cooling the electronic component, wherein the cooling device comprises: an evaporator for evaporating a liquid phase actuating fluid; a condenser for fluid condensation; a vapor tube connecting the evaporator and the condenser and flowing the gas to the gas phase; and a liquid tube connecting the condenser and the evaporator and flowing the liquid to operate the fluid, the evaporator a porous body having a plurality of cylindrical convex portions; a vapor chamber and a liquid chamber separated by the porous body; and a casing having a first portion for connecting the vapor tube and defining the vapor chamber; a second portion of the liquid chamber; and a plurality of protrusions are provided on the first portion and protrude toward the side of the second portion, and are embedded in each of the plurality of cylindrical protrusions of the porous body; and a plurality of a mask for covering a surface of each of the plurality of cylindrical protrusions, wherein the plurality of cylindrical protrusions of the porous body are in contact with a liquid contact surface of the liquid phase The area becomes smaller.