JP2010002128A - Heat transport device and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat transport device capable of enduring internal pressure at a high temperature without adopting a structure which deteriorates heat transport characteristics such as the thickening of an outer wall and the erection of a support column, etc. in the internal structure, and electronic equipment having the heat transport device. <P>SOLUTION: The outer wall 3 of the heat transport device 1 comprises nickel 6 having a linear expansion coefficient α<SB>1</SB>and copper 7 adhered to the inside of the nickel 6 and having a value of a linear expansion coefficient α<SB>2</SB>larger than the linear expansion coefficient α<SB>1</SB>. That is, the outer wall 3 comprises bimetal. In the high temperature state, the nickel 6 and the copper 7 adhered to the inside of the nickel 6 are expanded. At this time, since the copper 7 is expanded more largely compared to the nickel, stress 8 is generated in the nickel, that is, in the internal direction of a container 2. The stress 8 withstands stress (internal pressure stress) from the inside to the outside of the container 2 by the internal pressure P generated by heating the heat transport device 1. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a heat transport device that transports heat by a phase change of a working fluid, and an electronic apparatus including the heat transport device.

  In order to cool an electronic device such as a personal computer, a cooling device such as a heat pipe is used that transports heat generated from a heat generating portion of the electronic device to a condensing unit to dissipate heat.

  In these cooling devices, the working fluid vapor evaporated by the heat generated in the high temperature heat generating part of the electronic device moves to the low temperature condensing part, condenses in the condensing part, and releases heat. The object to be cooled is cooled.

  In recent years, with the enhancement of the performance of electronic devices and the like, heat generation from miniaturized ICs and the like contained therein has become a major problem. As a solution, there is a demand for an inexpensive cooling device that is small, thin, and highly efficient.

  By the way, when the cooling device is assembled to the heat generating part of the electronic device, brazing such as soldering is performed in order to reduce the contact thermal resistance with the heat generating part. At this time, there is a problem that the fluid inside the cooling device evaporates and expands due to heat during brazing, and the cooling device is damaged by the internal pressure.

In order to solve this problem, the outer surface of the cooling device is made thicker, or if the cooling device is a flat plate, a pillar or the like is provided inside to increase the strength of the cooling device to withstand internal pressure. The structure is disclosed (for example, refer to Patent Document 1 and Patent Document 2).
JP-A-11-287578 (paragraph [0015], FIG. 1) JP 2001-91172 A (paragraph [0007], FIG. 1)

  However, when the outer surface of the cooling device is thickened, the heat conduction performance is lowered. Moreover, when a support | pillar etc. are provided in the inside of a cooling device, the movement area | region of a working fluid reduces and heat exchange performance falls. Due to the structure for withstanding such an internal pressure, the heat transport characteristics are deteriorated.

  In view of the circumstances as described above, the object of the present invention is to increase the internal pressure at high temperatures without adopting a structure that deteriorates heat transport characteristics, such as thickening the outer wall or setting up a support post or the like in the internal structure. It is an object to provide a heat transport device capable of withstanding heat resistance and an electronic apparatus equipped with the heat transport device.

  In order to achieve the above object, a heat transport device according to an aspect of the present invention includes a first member having a first linear expansion coefficient and the first wire bonded to the inside of the first member. A container including an outer wall composed of a second member having a linear expansion coefficient larger than the expansion coefficient; and a working fluid that transports heat by changing phase in the container.

  When the outer wall is heated, stress is generated on the inner side of the first member, that is, the inner direction of the container due to the difference in the linear expansion coefficient between the first member and the second member bonded to the inner side. . Since this stress resists the internal pressure generated by heating the container, the container can be prevented from being damaged by the internal pressure. That is, it is possible to withstand internal pressure at a high temperature without adopting a structure that deteriorates heat transport characteristics such as thickening the outer wall or setting up a column or the like in the internal structure.

In the container, σ (Pa) represented by the following formula may satisfy a range of −σ _Y <σ <σ _Y.

α ₁ (Pa): the first linear expansion coefficient α ₂ (Pa): the second linear expansion coefficient t (m): the thickness of the outer wall of the container n: the first member and the second of a thickness ratio of the first member with the member thickness h ₁ (m) is _{h 1 = (n / n +} 1) and t, the thickness h ₂ (m) of the second member is h ₂ = ( 1 / n + 1) t.
E ₁ (Pa): longitudinal expansion coefficient of the first member E ₂ (Pa): longitudinal expansion coefficient of the second member T ₁ (° C.): temperature of the container before heating T ₂ (° C.) : Temperature of the container after being heated P (Pa): internal pressure of the container generated by heating the container a (m): width of the outer wall a = 0.01 (m)
σ _Y (Pa): The smaller value of the proof stress of the first member and the proof strength of the second member

Since σ represented by the above formula is included in the range of −σ _Y <σ <σ _Y , the thickness t of the outer wall of the container in the range, or the first member and the first The plate thickness ratio n with the member of 2 can be set to a desired value. For example, the heat transport device can be reduced in size by reducing the thickness t of the outer wall while σ satisfies the range of −σ _Y <σ <σ _Y. Or, in the case where σ satisfies the range of −σ _Y <σ <σ _Y , a member having a larger thermal conductivity is compared between the thermal conductivity of the first member and the thermal conductivity of the second member. The plate thickness ratio n is set so as to increase the thickness, and the heat transport characteristics of the heat transport device can be improved.

  The first member may be made of nickel. The second member may be made of copper. The working fluid may be made of pure water.

The thickness h ₁ of the first member made of the nickel and the thickness h ₂ of the second member made of the copper, may be represented than n = 0.56 as the plate thickness ratio n.

  An electronic device according to an embodiment of the present invention includes a first member having a first linear expansion coefficient and a linear expansion larger than the first linear expansion coefficient, which is bonded to the inside of the first member. A heat transport device having a container including an outer wall composed of a second member having a coefficient, a working fluid that transports heat by changing phase in the container, and thermally connected to the heat transport device Heat source.

  As described above, according to the present invention, it is possible to withstand internal pressure at high temperatures without adopting a structure that deteriorates heat transport characteristics such as thickening the outer wall or setting up a support post or the like in the internal structure. Can do.

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

  FIG. 1 is a schematic cross-sectional view showing a heat transport device according to an embodiment of the present invention. The heat transport device 1 includes a container 2 composed of an outer wall 3. A working fluid (not shown) that transports heat by phase change is hermetically sealed in the internal structure portion 4 of the container 2.

  FIG. 2 is an enlarged cross-sectional view showing a part A of the outer wall 3.

  As shown in FIG. 2, the outer wall 3 has a first member 6 having a first linear expansion coefficient, and a linear expansion larger than the first linear expansion coefficient, which is bonded to the inside of the first member. It is comprised with the 2nd member 7 which has a coefficient. That is, the outer wall 3 is made of bimetal. The first member 6 and the second member 7 are bonded together by, for example, plating or diffusion bonding.

  FIG. 3 is a diagram illustrating the operation of the outer wall 3 during heating. Here, it is assumed that the first member 6 is nickel 6 and the second member 7 is copper 7. The description will be made assuming that the working fluid is pure water.

  For example, when the heat transport device 1 is soldered to an IC or the like that is a heat source included in the electronic apparatus, the heat transport device 1 is exposed to a high temperature of about 270 degrees. In this high temperature state, the pure water contained in the internal structure part 4 of the container 2 becomes water vapor, and an internal pressure P (Pa) is generated due to its expansion. In the case of water vapor, the internal pressure P at a high temperature of about 270 degrees is about 5400 kPa. Due to the internal pressure P, a stress (hereinafter referred to as internal pressure stress) is generated on the outer wall 3 from the inside to the outside.

On the other hand, when the high temperature state is reached, the nickel 6 and the copper 7 expand. Comparing the linear expansion coefficient alpha ₂ of the linear expansion coefficient α ₁ (Pa) and copper 7 nickel 6 (Pa), the value is larger linear expansion coefficient alpha ₂ of copper 7. That is, since the copper 7 expands more greatly than the nickel 6, a stress 8 is generated inside the nickel 6, that is, in the container 2. This stress 8 resists the internal pressure stress.

FIG. 4 is a graph showing a value σ (Pa) obtained by subtracting the internal pressure stress from the stress 8 generated by the difference in linear expansion coefficient between the nickel 6 and the copper 7 bonded to the inside. . A plurality of thicknesses t (m) (see FIG. 1) of the outer wall 3 are taken, and a plurality of graphs of σ corresponding thereto are shown. The value of the plurality of t is in the range t = 0.8 × 10 ^-3 from the (m) of ^{t = 1.9 × 10 -3 (m} ), incremented every 0.1 × 10 ^-3 (m) ing. Correspondingly, the values taken by the graphs corresponding to the respective t are also increasing sequentially.

The horizontal axis is the thickness ratio n of nickel 6 and copper 7. From this n and the thickness t of the outer wall 3, the thickness h ₁ (m) of the nickel 6 is h ₁ = (n / n + 1) t, and the thickness h ₂ (m) of the copper 7 is h ₂ = (1 / N + 1) t. The vertical axis is σ (Pa).

In the range where σ is smaller than 0, the internal pressure stress is larger than the stress 8. However, if the value of σ _Y (Pa) is the smaller value of the proof stress of nickel 6 and the proof strength of copper 7, if the σ is in the range of −σ _Y <σ, the outer wall 3 is not damaged and the internal pressure is not damaged. Can withstand P. In the range where σ is larger than 0, the stress 8 is larger than the internal pressure stress, so that the influence of the internal pressure P on the container 2 can be greatly reduced. On the other hand, when σ is larger than σ _Y (Pa), the outer wall 3 may be damaged. That is, as shown in FIG. 4, if σ satisfies the range of −σ _Y <σ <σ _Y , the heat transport device 1 can withstand the internal pressure P generated by heating the container 2 and Can work. In this example, σ _Y is the proof stress of copper 7.

  σ will be described in detail.

FIG. 5A is a cross-sectional view of copper 7 with four sides fixed, and FIG. 5B is a plan view thereof. The thickness of the copper 7 is h ₂ , the width a (m) = 0.01, and the length b (m) = 1 (unit length). The copper 7 has the same strength as the internal pressure P.

Here, the maximum deflection ω _max (m) and the maximum bending stress σ _max (Pa) of the copper 7 are expressed as follows. E ₂ (Pa) is a longitudinal expansion coefficient of copper 7. γ is a deflection coefficient of copper 7, and γ = 0.03. Β is the maximum stress coefficient of copper 7, and β = 0.5.

Here, the value E ₂ = 1.1 × 10 ¹¹ (PA) of the longitudinal expansion coefficient E ₂ of the copper 7 and the value σ _Y = 7.0 × 10 ⁷ (Pa) of the proof stress σ _Y of the copper 7 are used. When the P is 5400 kPa, the thickness h ₂ of the copper 7 that the copper 7 can withstand P is obtained, and h ₂ is expressed as follows.

When the thickness h ₂ of the copper 7 is larger than 1.96 (mm), the copper 7 can withstand the internal pressure P due to the water vapor. Therefore, if the container 2 is made of copper 7 having a thickness greater than 1.96 (mm), it can withstand the internal pressure P. However, in this case, the purpose of downsizing the container 2 cannot be obtained.

FIG. 6 is a diagram illustrating the elongation of the copper 7 when the copper 7 is heated and the temperature of the copper 7 is changed from T ₁ ° C to T ₂ ° C. l is the length of the copper 7 before being heated. l ′ is the length of the copper 7 after being heated. lambda is the elongation of the copper 7 by heating, is expressed as _{λ = lα 2 (T 2 -T} 1).

As elongation λ of the copper 7 is not generated, idea to fix the length of the copper 7, compressive stress sigma _C occurs within a copper 7. This compressive stress σ _C is obtained.

First, the unit strain e of the copper 7 is obtained. Here, 1 + α ₂ (T ₂ −T ₁ ) is as close as possible to 1.

From the unit strain e, the compressive stress σ _C is expressed as follows.

Next, the bonded copper 7 and nickel 6 are heated, and when their temperature is changed from T ₁ ° C to T ₂ ° C, the compression stress σ _N generated in the nickel 6 and the compression generated in the copper 7 Obtain the stress σ _C.

When the cross-sectional area of nickel 6 is A ₁ and the cross-sectional area of copper 7 is A ₂ , the σ _N and the σ _C are expressed as follows. E ₁ (Pa) is the longitudinal expansion coefficient of nickel 6.

Therefore, the moment M ₁ (N · m) generated in the nickel 6, the moment M ₂ (N · m) generated in the copper 7, and the sum thereof are expressed as follows. h ₁ (m) is the thickness of nickel 6, and h ₂ (m) is the thickness of copper 7. When the thickness ratio of nickel 6 and copper 7 is n, h ₁ is h ₁ = (n / n + 1) t and h ₂ from the total thickness t of the bonded nickel 6 and copper 7. Is represented as h ₂ = (1 / n + 1) t.

From the equation representing the sum of the moment M ₁ and the moment M ₂ , the overall internal stress σ _{N + C} when nickel 6 and copper 7 are bonded together is represented by the following equation. Z is the overall section modulus of the bonded nickel 6 and copper 7. Z is expressed by Z = bt ^2/6. As described above, b = 1 (m).

The bonded nickel 6 and copper 7 constitute the outer wall 3 included in the container 2 with the copper 7 being the inner side. Since the bonded nickel 6 and copper 7 it was is restrained as the outer walls 3, 2 times the stress of the internal stress sigma _{N + C} of the whole above, the inner nickel 6, i.e. generated inside direction of the container 2. The stress that is twice the total internal stress σ _{N + C} thus generated is the stress 8.
When the stress 8 is σ ₈ , σ ₈ is expressed by the following equation.

When the formula representing σ ₈ is arranged by the formula representing the σ _N , the formula representing the σ _C , the h ₁ and the h ₂ , the formula representing the σ ₈ is arranged as follows.

When the internal pressure stress is σ ₉ , σ ₉ is expressed by the following equation.

The σ is a value obtained by subtracting the internal pressure stress from the stress 8 caused by the difference in linear expansion coefficient between the nickel 6 and the copper 7 bonded to the inside thereof. Therefore, σ is represented by the following equation from the equation representing σ ₈ and the equation representing σ ₉ .

In the formula representing σ, E ₁ , E ₂ , P, and a are fixed values. Therefore, by determining assumes a temperature T ₂ after heating to the temperature T ₁ of the before the heating of the container 2 by the soldering, the expression for σ, the thickness of the outer wall 3 of the container 2 t And the plate thickness ratio n between nickel 6 and copper 7. Accordingly, the thickness t of the outer wall 3 or the plate thickness ratio n can be set to a desired value while the σ satisfies the range of −σ _Y <σ <σ _Y. In the graph of FIG. 4 of this example, it is assumed that T ₁ is 20 ° C. and T ₂ is 270 ° C.

As shown in the graph of FIG. 4, when the plate thickness ratio n is n = 0.56, the value of σ increases. In the graph of σ corresponding to the case where the thickness t of the outer wall 3 is t = 0.9, the value of σ at n = 0.56 satisfies the range of −σ _Y <σ <σ _Y. Further, a graph corresponding to the case of t ≧ 0.9 (a graph corresponding to the case of 0.9 ≦ t ≦ 1.9) is a value of n that satisfies the above-mentioned range of −σ _Y <σ <σ _Y. Exists. That is, the thickness t of the outer wall 3 of the container 2 is set so that the thickness ratio n is set to an intended value when t ≧ 0.9 (when 0.9 ≦ t ≦ 1.9). Σ satisfies the range of −σ _Y <σ <σ _Y.

Reference is made to the graph corresponding to the case of t = 1.9. In this graph, the value of the plate thickness ratio n is almost 0, and the value of σ satisfies the range of −σ _Y <σ <σ _Y. The thickness h ₁ of the nickel 6 is expressed as h ₁ = (n / n + 1) t, and the thickness h ₂ of the copper 7 is expressed as h ₂ = (1 / n + 1) t. The thickness h _{1 of} 6 is approximately 0, and the thickness h ₂ of copper 7 is approximately t or 1.9. Therefore, if the thickness h ₂ of the copper 7 is approximately 1.9, the above 8 resists the internal pressure stress even if the nickel to be bonded is approximately 0. This means that the internal pressure P due to the water vapor can be withstood as in the case where the thickness h ₂ of the copper 7 is larger than 1.96 (mm). The purpose of conversion is not obtained.

For example, when the thickness t of the outer wall 3 is t = 1, which is smaller than the above 1.96 (mm), the above-mentioned σ is in the range of −σ _Y <σ <σ _Y by setting the plate thickness ratio n to a desired value. Fulfill. That is, the heat transport device 1 can withstand the internal pressure P at a high temperature without adopting a structure that deteriorates the heat transport characteristics such as thickening the outer wall. As a result, the heat transport device 1 can be reduced in size, thickness, and weight.

In the case of t = 1, from the graph shown in FIG. 4, the sheet thickness ratio n is in the range of 0.12 <n <0.43 and 0.69 <n <2.33, and the σ is −σ _Y <σ <. It satisfies the range of σ _Y. When the thermal conductivity of nickel 6 is compared with the thermal conductivity of copper 7, the thermal conductivity of copper 7 is greater. Therefore, a thickness of t = 1 of the outer wall 3, the thickness h ₁ of nickel 6 is small, and sets the thickness ratio n such that the thickness h ₂ of copper 7 increases. Since the thickness h ₁ of the nickel 6 is expressed as h ₁ = (n / n + 1) t and the thickness h ₂ of the copper 7 is expressed as h ₂ = (1 / n + 1) t, the thickness ratio n can be reduced. The thickness h ₁ of the nickel 6 is reduced, and the thickness h ₂ of the copper 7 is increased. That is, the plate thickness ratio n may be set within a range satisfying 0.12 <n <0.43, and typically n = 0.2. Thus, the heat transport property of the heat transport device can be improved by setting the plate thickness ratio n so as to increase the thickness of the copper 7 having higher thermal conductivity.

  Further, the heat transport device 1 can withstand the internal pressure at a high temperature without adopting a structure that deteriorates the heat transport characteristics such as setting up a column or the like in the internal structure portion 4 of the container 2. Thereby, for example, the moving region of the working fluid can be increased, and the heat transport characteristics of the heat transport device 1 can be improved.

  In this example, the container 2 is constituted by the outer wall 3, but the outer wall 3 is included in a desired position of the outer wall of the container 2 when only the portion soldered to an IC or the like is the outer wall 3, for example. May be appropriately designed.

  FIG. 7 is a table showing examples of materials used as a combination of the first member 6 and the second member 7. The materials shown in the table of FIG. 4 may be used in place of nickel 6 and copper 7 used in this example, but are not limited thereto.

  Examples of the working fluid contained in the internal structure portion 4 of the container 2 include pure water, ethanol, methanol, acetone, and isopropyl alcohol. Alternative chlorofluorocarbon, ammonium, etc. are used. However, it is not limited to these.

From the combination of the first member 6 and the second member 7 shown in FIG. 7 and the characteristics of the working fluid used and the formula representing σ, σ satisfies the range of −σ _Y <σ <σ _Y. Among them, the thickness t of the outer wall 3 or the plate thickness ratio n may be set to a desired value.

  The first member 6 and the second member 7 may be bonded together by brazing, that is, welding, or may be bonded using an adhesive depending on the material. Alternatively, they may be bonded by the above-described plating process, diffusion bonding, or the like. In the case of nickel 6 and copper 7 shown in this example, the heat transport device 1 can be manufactured at low cost by bonding them together by plating. For example, in the process of assembling the container 2, the heat transport device 1 can be manufactured at a lower cost by bonding the first member 6 and the second member 7 together.

  In this example, the case where the heat transport device 1 is soldered to an IC or the like included in an electronic apparatus has been described. However, after the heat transport device 1 is soldered, for example, other devices are on the same substrate. The same effect can be obtained when soldered inside.

  FIG. 8 is a perspective view showing a specific embodiment of the heat transport device 1 shown in FIG. FIG. 9 is a cross-sectional view showing the heat source connected to the heat transport device 1 in a state where the heat source is connected to the heat transport device 1, and is a cross-sectional view taken along line AA in FIG.

  As shown in FIG. 9, the heat transport device 1 is formed by laminating a Bessel-like lower substrate 500, an upper substrate 200 provided to face the lower substrate 500, and the lower substrate 500 and the upper substrate 200. And a plurality of liquid phase flow path substrates 600 constituting the flow path of the working fluid. The lower substrate 500 and the upper substrate 200 are bonded by, for example, diffusion bonding or other methods to form the container 2.

  It is sufficient that at least one of the upper substrate 200 and the lower substrate 500 is made of the bimetal described above. The liquid phase flow path substrate 600 is typically made of oxygen-free copper, tough pitch copper, or a copper alloy. However, the present invention is not limited to this, and the liquid phase flow path substrate 600 may be made of a metal other than copper, or other materials having high thermal conductivity may be used.

  FIG. 10 is a perspective view showing the liquid phase flow path substrate 600.

  The liquid phase flow path substrate 600 is provided with a plurality of holes 9 for generating a capillary force. A plurality of liquid phase flow path substrates 600 are stacked and accommodated in the container 2. A liquid-phase flow path 610 that allows a liquid-phase working fluid to circulate by capillary force is formed by the holes 9 provided in the plurality of laminated liquid-phase flow path substrates 600. (See FIG. 9).

  The plurality of liquid phase flow path substrates 600 are stacked so that a space is secured on the upper substrate 200 side in the container 2. The space becomes the gas phase flow path 410 through which the gas phase working fluid flows. (See FIG. 9).

  The plurality of holes 9 are not limited to the form formed by forming holes in the substrate as shown in FIG. 10, and may be a plurality of holes having a mesh structure.

  Typically, about 4 to 20 liquid phase flow path substrates 600 are stacked, but the present invention is not limited to this. The thickness of the plurality of liquid phase flow path substrates 600 is typically 0.02 mm to 0.05 mm, respectively, but is not limited thereto.

  The plurality of liquid phase flow path substrates 600 may be joined by brazing, that is, welding, or may be joined using an adhesive depending on the material. Alternatively, they may be joined by plating, diffusion bonding, or the like.

  The operation of the heat transport device 1 configured as described above will be described with reference to FIG.

  As shown in FIG. 9, a heat source 50 such as an IC is in contact with one end portion of the lower substrate 500. In this case, the heat transport device 1 defines the end where the heat source 50 is in contact with the heat absorbing portion V. The other end is defined as a heat radiating part W. The liquid phase working fluid absorbs heat from the heat source 50 and evaporates in the heat absorbing portion V.

  The gas phase working fluid that has undergone a phase change from the liquid phase working fluid moves from the liquid phase channel 610 to the gas phase channel 410. The gas-phase working fluid flows in the gas-phase flow path 410 so as to go from the heat-absorbing part V to the heat-dissipating part W, and releases heat in the heat-dissipating part W and condenses. The liquid phase working fluid that has undergone a phase change from the gas phase working fluid in the heat radiating portion W flows to the heat absorbing portion V via the liquid phase flow path 610 by the capillary force of the plurality of holes 9. Therefore, the heat is again absorbed from the heat source 50, and the phase is changed to the gas phase working fluid. By repeating such operations, the heat of the heat source 50 is transported by the heat transport device 1.

  Each operation region indicated by an arrow in FIG. 9 indicates a certain standard or reference, and each operation region is slightly shifted depending on the amount of heat of the heat source 50, so that each operation is clearly defined for each region. They are not divided.

  A member for heat dissipation such as a heat sink (not shown) may be thermally connected to the heat radiating portion W. In this case, the heat transported by the heat transport device 1 is transmitted to the heat sink and radiated from the heat sink.

  In FIG. 9, a heat source 50 indicated by a one-dot chain line may be connected to one end of the upper substrate 200. Further, the heat source 50 may be connected to both one end of the upper substrate 200 and one end of the lower substrate 500 on the same side.

  FIG. 11 is a perspective view showing a notebook PC (Personal Computer) as an electronic apparatus including the heat transport device 1. A circuit board 12 is disposed in the housing 11 of the PC 10. For example, a CPU (Central Processing Unit) 13 is mounted on the circuit board 12. The heat transport device 1 is thermally connected to the CPU 13, and a heat sink (not shown) is thermally connected to the heat transport device 1.

  Embodiments according to the present invention are not limited to the embodiments described above, and other various embodiments are conceivable.

  The planar shape of the planar shape of the heat transport device 1 was a quadrangle. However, the planar shape may be a circle, an ellipse, a polygon, or any other shape.

  A PC is taken as an example of the electronic apparatus in FIG. However, the present invention is not limited to this, and the electronic devices include PDA (Personal Digital Assistance), electronic dictionary, camera, display device, audio / visual device, projector, mobile phone, game device, car navigation device, robot device, laser generator. And other electrical appliances.

It is typical sectional drawing which shows the heat transport device which concerns on one embodiment of this invention. It is an expanded sectional view showing a part of outer wall. It is a figure which shows operation | movement of the outer wall at the time of a heating. It is a graph which shows value (sigma) (Pa) obtained by subtracting internal pressure stress from the stress which arises by the difference in the linear expansion coefficient of nickel and copper bonded inside. It is sectional drawing (A) and top view (B) of copper with which four sides were fixed. Copper is heated, when the temperature of the copper becomes T ₂ ° C. from T ₁ ° C., illustrates a stretch of copper. It is a table | surface which shows the example of the material used as a combination of a 1st member and a 2nd member. FIG. 2 is a perspective view showing a specific embodiment of the heat transport device shown in FIG. 1. It is sectional drawing which shows the heat source connected with the said heat transport device in the state with which the heat source was connected to the heat transport device. It is a perspective view which shows a liquid phase flow-path board | substrate. It is a perspective view which shows notebook type PC as an electronic device provided with the heat transport device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heat transport device 2 Container 3 Outer wall 4 Internal structure part 6 1st member, nickel 7 2nd member, copper 8 Stress 9 hole 10 PC
11 Housing 12 Circuit board 13 CPU
50 Heat Source 200 Upper Substrate 410 Gas Phase Channel 500 Lower Substrate 600 Liquid Phase Channel Substrate 610 Liquid Phase Channel

Claims (5)

A first member having a first linear expansion coefficient, and a second member bonded to the inside of the first member and having a linear expansion coefficient greater than the first linear expansion coefficient. A container including an outer wall,
A heat transport device comprising: a working fluid that transports heat by changing phase in the container. The heat transport device according to claim 1,
The container is a heat transport device in which σ (Pa) represented by the following formula satisfies a range of −σ _Y <σ <σ _Y.

α ₁ (Pa): the first linear expansion coefficient α ₂ (Pa): the second linear expansion coefficient t (m): the thickness of the outer wall of the container n: the first member and the second The thickness h ₁ (m) of the _first member is h ₁ = (n / n + 1) t, and the thickness h ₂ (m) of the _second member is h ₂ = ( 1 / n + 1) t.
E ₁ (Pa): longitudinal expansion coefficient of the first member E ₂ (Pa): longitudinal expansion coefficient of the second member T ₁ (° C.): temperature of the container before heating T ₂ (° C.) : Temperature of the container after being heated P (Pa): internal pressure of the container generated by heating the container a (m): width of the outer wall a = 0.01 (m)
σ _Y (Pa): The smaller value of the proof stress of the first member and the proof strength of the second member A heat transport device according to claim 2, comprising:
The first member is made of nickel;
The second member is made of copper;
The working fluid is a heat transport device made of pure water. A heat transport device according to claim 3,
Heat transport device and the thickness h ₂ of the second member having a thickness of h ₁ and the copper of the first member made of the nickel is expressed from n = 0.56 as the plate thickness ratio n. A first member having a first linear expansion coefficient, and a second member bonded to the inside of the first member and having a linear expansion coefficient greater than the first linear expansion coefficient. A heat transport device having a container including an outer wall and a working fluid that transports heat by changing phase in the container;
An electronic device comprising: a heat source thermally connected to the heat transport device.

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