Contact thermal resistance estimation device, contact thermal resistance estimation method, and contact thermal resistance estimation program

Abstract

To accurately estimate a contact thermal resistance in a contact part of members even when the members are in contact with each other at a low contact pressure.SOLUTION: A contact thermal resistance estimation device acquires, by a first information acquisition unit 11, information on the diameter of real contact points scattered on a contact interface, in addition to acquiring, by a second information acquisition unit 12, information on the structural properties and thermal properties of a first member and a second member in contact with each other and information on the thermal properties of an air space formed on the contact interface, and calculates, by a contact thermal resistance calculation unit 13, the contact thermal resistance of the entire contact interface by a computation expression using these pieces of acquired information, thereby allowing calculation of the contact thermal resistance by a computation expression in accordance with a case where the size of the real contact point scattering on the contact interface does not vary, and accurate estimation of the contact thermal resistance even when the members are in contact with each other at a low contact pressure.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a contact thermal resistance estimation device, a contact thermal resistance estimation method, and a contact thermal resistance estimation program, and more particularly to a technique for estimating contact thermal resistance at a contact portion where two members come into contact. [Background technology]

[0002] The temperature of electronic components that are assumed to dissipate heat to the housing or heat sink of the electronic device varies greatly depending on the contact thermal resistance that occurs at the contact surface between the housing or heat sink and the electronic component. Therefore, to safely use electronic components within the specified temperature range, it is necessary to accurately monitor and control the contact thermal resistance.

[0003] Conventionally, the Tachibana-Sanogawa estimation formula has often been used to estimate thermal contact resistance. This estimation formula estimates thermal contact resistance from parameters such as the thermal conductivity, Vickers hardness, and contact pressure of the components. There is also known technology that uses this Tachibana-Sanogawa estimation formula in conjunction with simulation to generate a thermal fluid analysis model of a component (see, for example, Patent Document 1). The technology described in Patent Document 1 utilizes the Tachibana-Sanogawa estimation formula to estimate the thermal contact resistance of the contact area, and generates a thermal fluid analysis model that includes the estimated thermal contact resistance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-122506 Summary of the Invention [Problem to be solved by the invention]

[0005] As mentioned above, the Tachibana-Sanogawa equation is often used to estimate thermal contact resistance. However, this equation was created assuming that similar metal materials come into contact with each other at a high contact pressure of 10 MPa or more. Therefore, it is difficult to accurately estimate the thermal contact resistance at contact points where components come into contact with each other at a contact pressure lower than that assumed by the Tachibana-Sanogawa equation.

[0006] The present invention has been made to solve such problems, and aims to make it possible to estimate the thermal contact resistance at the contact point with higher accuracy even when the contact pressure between the components is lower than that assumed by the Tachibana-Sanogawa estimation formula. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, in the present invention, in addition to obtaining information on the structural and thermal properties of the first and second members, and information on the thermal properties of the air layer that forms at the contact interface between the first and second members, information on the diameter of each of the actual contact points scattered at the contact interface between the first and second members is obtained, and the overall contact thermal resistance of the contact interface is calculated using a formula that uses this obtained information as a variable. [Effects of the Invention]

[0008] According to the present invention configured as described above, unlike the Tachibana-Sanogawa estimation formula, which assumes that the size of each contact point scattered across the entire contact surface does not change when the first and second members come into contact with each other at a high contact pressure, the entire thermal contact resistance of the contact interface is calculated using a calculation formula that is suited to the case where the size of the actual contact points scattered across the contact interface changes when the first and second members come into contact with each other at a lower contact pressure.As a result, even when the members come into contact with each other at a contact pressure lower than that assumed by the Tachibana-Sanogawa estimation formula, the thermal contact resistance at the contact area can be estimated with greater accuracy. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a block diagram showing an example of the functional configuration of a contact thermal resistance estimation device according to a first embodiment; [Figure 2] FIG. 3 is a diagram schematically illustrating a contact state between a first member and a second member. [Figure 3] FIG. 3 is a diagram for explaining the contents of a calculation formula used by a contact thermal resistance calculation unit according to the first embodiment. [Figure 4] FIG. 10 is a diagram showing an equivalent circuit when calculating a combined resistance of four types of thermal resistance. [Figure 5] FIG. 10 is a diagram for explaining the formulation of thermal resistance due to reduction of heat flow. [Figure 6] FIG. 4 is a diagram showing the estimation accuracy of contact thermal resistance according to the first embodiment together with the estimation accuracy of contact thermal resistance according to the prior art. [Figure 7] FIG. 3 is a diagram showing a model used when verifying the estimation accuracy of contact thermal resistance in the first embodiment. [Figure 8] 4 is a flowchart showing an example of the operation of the contact thermal resistance estimation device according to the first embodiment. [Figure 9] FIG. 4 is a diagram showing the estimation accuracy of the contact thermal resistance calculated by the simplified formula of the first embodiment. [Figure 10] FIG. 10 is a block diagram showing an example of the functional configuration of a contact thermal resistance estimation device according to a second embodiment. [Figure 11] FIG. 10 is a diagram for explaining height information acquired by a property data analysis unit according to the second embodiment. [Figure 12] 10A and 10B are diagrams for explaining actual contact points that occur depending on the gap length between a first member and a second member. [Figure 13] 10 is a flowchart showing an example of the operation of the contact thermal resistance estimation device according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] (First embodiment) A first embodiment of the present invention will now be described with reference to the drawings. Fig. 1 is a block diagram showing an example of the functional configuration of a contact thermal resistance estimation device according to the first embodiment. As shown in Fig. 1, a contact thermal resistance estimation device 10 according to the first embodiment includes, as functional components, a first information acquisition unit 11, a second information acquisition unit 12, and a contact thermal resistance calculation unit 13. More specifically, the first information acquisition unit 11 includes, as functional components, an interface property data acquisition unit 11a and a property data analysis unit 11b.

[0011] The functional blocks 11 to 13 can be configured by any of hardware, a DSP (Digital Signal Processor), and software. For example, when configured by software, the functional blocks 11 to 13 are actually configured with a CPU, RAM, ROM, etc. of a computer, and are realized by running a contact thermal resistance estimation program stored in a recording medium such as RAM, ROM, a hard disk, or a semiconductor memory.

[0012] The contact thermal resistance estimation device 10 is a device for estimating the contact thermal resistance at a contact portion where a first member and a second member come into contact. For example, the first member is a member of an electronic component, and the second member is a member of a housing or a heat sink of an electronic device. In this case, the contact thermal resistance estimation device 10 estimates the contact thermal resistance at the contact interface between the electronic component and the housing or the heat sink by a method described in detail below.

[0013] FIG. 2 is a diagram schematically illustrating the contact state between a first member 101 and a second member 102. At least one of the first member 101 and the second member 102 has minute surface roughness (unevenness). The first member 101 and the second member 102 do not make surface contact over the entire contact area, but make localized contact at multiple contact points (contact regions with minute areas). These contact points are scattered in areas where at least one of the first member 101 and the second member 102 is convex. These multiple contact points scattered at the contact interface between the first member 101 and the second member 102 are referred to as "actual contact points" in this specification. When the first member 101 and the second member 102 make contact with each other with a relatively low contact pressure, the sizes of the multiple actual contact points may vary.

[0014] The schematic diagram of Fig. 2 shows an example in which both the first member 101 and the second member 102 have minute surface roughness. Fig. 2(a) is a perspective view of the entire contact portion. Fig. 2(b) is a side cross-sectional view showing the contact state of one actual contact point where a protrusion 111 of the first member 101 comes into contact with a protrusion 121 of the second member 102. Fig. 2(c) is a side cross-sectional view showing the contact state of multiple actual contact points 131 scattered on the contact interface between the first member 101 and the second member 102. -i 2 is a plan view showing (i=1, 2, . . . ). Below, the functional blocks 11 to 13 shown in FIG. 1 will be described with reference to the schematic diagram of FIG.

[0015] The first information acquisition unit 11 acquires actual contact points 131 scattered on the contact interface between the first member 101 and the second member 102 by the interface property data acquisition unit 11a and the property data analysis unit 11b. -i Each diameter D -i Get information about.

[0016] The interface property data acquisition unit 11a acquires property data of the contact interface when the first member 101 and the second member 102 are actually brought into contact with each other. For example, the interface property data acquisition unit 11a acquires property data of the contact interface using a laser microscope. A laser microscope is a microscope that uses a He-Ne gas laser, a semiconductor laser, or the like as a light source, and is used to measure the three-dimensional shape and surface roughness of an object. The interface property data acquisition unit 11a uses the laser microscope to acquire property data of the contact interface from a plurality of actual contact points 131 as shown in FIG. 2(c). -i Image data configured to be able to identify the

[0017] For example, the contact interface between the first member 101 and the second member 102 in contact with each other is observed with a laser microscope from multiple lateral positions (for example, in the case of a rectangular parallelepiped member as shown in FIG. 2(a), from four positions on each side), and multiple image data obtained by this observation are analyzed to identify multiple actual contact points 131. -i The position and size on the plane where the contact interface exists are calculated, and image data of the contact interface viewed from above is generated as shown in Figure 2(c). Note that this is just an example of processing, and the method is not limited to this.

[0018] The property data analysis unit 11b analyzes the property data of the contact interface acquired by the interface property data acquisition unit 11a (image data generated by imaging the contact interface with a laser microscope), thereby determining the actual contact points 131 scattered on the contact interface. -i Each diameter D -i For example, the property data analysis unit 11b acquires information on the actual contact point 131 on the image data. -i The number of pixels in the area where the contact point exists is analyzed, and the actual contact point 131 is calculated based on the number of pixels and the actual size information per pixel. -i Diameter D -i Calculate.

[0019] The second information acquisition unit 12 acquires information on the structural properties and thermal properties of the first member 101 and the second member 102, and information on the thermal properties of the air layer formed at the contact interface between the first member 101 and the second member 102. Hereinafter, this information acquired by the second information acquisition unit 12 may be collectively referred to as "physical property information."

[0020] Here, the second information acquisition unit 12 acquires the entire area A of the contact interface, and the height δ1 of the convex portion 111 and the height δ2 of the convex portion 121 shown in FIG. 2(b) as information relating to the structural properties of the first member 101 and the second member 102. The height δ1 of the convex portion 111 and the height δ2 of the convex portion 121 are information indicating the surface roughness of each member 101, 102. Furthermore, the second information acquisition unit 12 acquires the thermal conductivity λ1 of the first member 101 and the thermal conductivity λ2 of the second member 102 as information relating to the thermal properties of the first member 101 and the second member 102. Furthermore, the second information acquisition unit 12 acquires the thermal conductivity λ1 of the air layer 140 as information relating to the thermal properties of the air layer 140 formed at the contact interface as shown in FIG. 2(b). air Get.

[0021] The physical property information acquired by the second information acquisition unit 12 is information of known values ​​regarding both the first member 101 and the second member 102. For example, the second information acquisition unit 12 acquires physical property information input to a computer by a user using an input device such as a keyboard or a touch panel. Alternatively, the second information acquisition unit 12 may acquire physical property information that is pre-stored in a storage medium.

[0022] The contact thermal resistance calculation unit 13 calculates the overall contact thermal resistance R of the contact interface by a calculation formula using the information acquired by the first information acquisition unit 11 and the second information acquisition unit 12 as variables. th 3 is a diagram for explaining the content of the calculation formula used by the contact thermal resistance calculation unit 13. As shown in FIG. 3, the calculation formula used by the contact thermal resistance calculation unit 13 is -i Thermal resistance r due to the reduction of heat flow to th-coni and actual contact point 131 -i Thermal resistance rth-ri and the thermal resistance r of the air layer 140 th-air and the actual contact point 131 of the second member 102. -i Thermal resistance r due to expansion of heat flow from th-spi This is the formula for calculating the combined resistance.

[0023] Figure 4 shows four types of thermal resistance r th-coni ,r th-ri ,r th-air ,r th-spi 4 is a diagram showing an equivalent circuit for calculating the combined resistance of the actual contact point 131. -i Three thermal resistances for each th-coni ,r th-ri ,r th-spi A series circuit of the air layers 140 is formed, and the thermal resistance r th-air Actual contact point 131 -i Therefore, the actual contact point 131 is -i When the number of contacts is n (i=1,2,...,n), the total thermal contact conductance K th (Contact thermal resistance R th The reciprocal of (the value of the square root ... sine wave) is expressed as follows (Equation 1):

[0024]

number

[0025] Here, the actual contact point 131 of the first member 101 -i Thermal resistance r due to the reduction of heat flow to th-coni , real contact point 131 -i Thermal resistance r th-ri , the thermal resistance r of the air layer 140 th-air , the actual contact point 131 of the second member 102 -i Thermal resistance r due to expansion of heat flow from th-spi can be expressed by the following (Equation 2) to (Equation 5), respectively. i is the actual contact point 131 -i Area of ​​(a i =πD i 2 / 4). Substituting these (Equation 2) to (Equation 5) into (Equation 1), the contact thermal resistance R th is expressed as (Equation 6). This (Equation 6) is used by the contact thermal resistance calculation unit 13 to calculate the contact thermal resistance R th This is the formula used to calculate

[0026]

number

[0027] The calculation formula shown in (Formula 6) is obtained by calculating the actual contact point 131 of the first member 101 shown in (Formula 2). -i Thermal resistance r due to the reduction of heat flow to th-coni and the actual contact point 131 of the second member 102 shown in (Equation 5) -i Thermal resistance r due to expansion of heat flow from th-spi The information acquired by the first information acquisition unit 11 and the second information acquisition unit 12 (the actual contact point 131) -i Diameter D i , the thermal conductivity λ1 of the first member 101, and the thermal conductivity λ2 of the second member 102) as variables. This is one of the features that makes it different from the conventional estimation formula by Tachibana and Sanogawa, which used fixed values.

[0028] Actual contact point 131 on the first member 101 -i Thermal resistance r due to the reduction of heat flow to th-coni (Equation 2) expresses the actual contact point 131 in the second member 102. -i Thermal resistance r due to expansion of heat flow from th-spi (Equation 5) expresses the actual contact point 131 -i This formula is based on the idea of ​​concentrated thermal resistance, and is created by regarding the temperature field around the object as a hemisphere. Figure 5 is a diagram used to explain the details of this formulation. The meanings of (Equation 2) and (Equation 5) will be explained below using this Figure 5.

[0029] First, as shown in FIG. 5(a), the actual contact point 131 -i Area a iDefine an inner hemisphere 51 with a radius d having a surface area S equivalent to that. The center position of this inner hemisphere 51 is assumed to coincide with the center position of the actual contact point 131 -i And it is considered that heat flows toward this inner hemisphere 51. The surface area S of the inner hemisphere 51 is S = 2πd 2 The area a of the actual contact point 131 -i is a i = πD i / 4, so S = a i 2 From this, the radius d of the inner hemisphere 51 is expressed as d = D i / 2√2. i

[0030] Next, as shown in Fig. 5(b), consider the thermal resistance dr of a hemispherical micro-region dL located at a distance L from the center of the actual contact point 131 -i . This thermal resistance dr is expressed as in the following (Equation 7). And, as shown in the following (Equation 8), by accumulating the thermal resistance dr of the micro-region dL from the position on the surface of the inner hemisphere 51 (= D i / 2√2) to the position D, the concentrated thermal resistance r th1_ct generated in the first member 101 is obtained. Considering the accumulation range of the thermal resistance dr to be up to a position far from the center of the inner hemisphere 51, D i << D, and it becomes (Equation 2) ignoring 1 / D. (Equation 5) can also be defined in the same way of thinking.

[0031]

Equation

[0032] Fig. 6 is a diagram showing the verification results of the estimation accuracy of the contact thermal resistance R th according to the first embodiment, together with the estimation accuracy of the contact thermal resistance according to the prior art. In the accuracy verification, regarding the contact thermal resistance R th of the entire contact interface in the model shown in Fig. 7, the contact thermal resistance R th obtained by a contact thermal resistance estimation program incorporating the calculation formula shown in (Equation 6), and the contact thermal resistance R th_sim obtained by simulating the actual heat flow are considered.The degree of consistency between the actual contact point 131 was confirmed. -i Diameter D i The parameters relating to the physical property information of the first member 101 and the second member 102 are changed within the ranges shown in FIG. 7, and the thermal contact resistance R calculated by applying this embodiment to 375 models with different combinations of the parameters is th and the thermal contact resistance R obtained by simulation. th_sim The comparison results are shown in Figure 6(a), and the thermal contact resistance R th ,R th_sim The plots are concentrated near the solid line with an error of 0%, which indicates a good agreement of the thermal contact resistance R th It was confirmed that the above could be estimated.

[0033] On the other hand, Fig. 6(b) shows the thermal contact resistance R calculated by the estimation formula of Tachibana and Sanogawa, which is used in the prior art described in Patent Document 1. th_ts and the thermal contact resistance R obtained by simulation. th_sim As is clear from Fig. 6(b), the estimated contact thermal resistance R th_ts is the thermal contact resistance R obtained by simulation th_sim Even if the estimation formula of Tachibana and Sanogawa is used, the thermal contact resistance R th_ts It was confirmed that it was not possible to estimate correctly.

[0034] 8 is a flowchart showing an example of operation of the contact thermal resistance estimation device 10 according to the first embodiment (an example of processing in the contact thermal resistance estimation method). As shown in FIG. 8, the interface property data acquisition unit 11a of the first information acquisition unit 11 uses a laser microscope to acquire property data of the contact interface when the first member 101 and the second member 102 are actually brought into contact with each other (step S1). Next, the property data analysis unit 11b performs image analysis of the property data of the contact interface acquired by the interface property data acquisition unit 11a to identify actual contact points 131 scattered on the contact interface. -i Each diameter D -i The information is acquired (step S2).

[0035] The second information acquisition unit 12 acquires physical property information of the first member 101 and the second member 102 (total area A of the contact interface, heights δ1 and δ2 of the convex portions 111 and 121, thermal conductivities λ1, λ2, λ air ) is obtained (step S3). Note that the processing of steps S1 and S2 and the processing of step S3 may be performed in reverse order. When the necessary information is obtained in steps S1 to S3, the contact thermal resistance calculation unit 13 calculates the overall contact thermal resistance R of the contact interface by the calculation formula shown in (Equation 6) using the obtained information as variables. th (Step S4) This completes the process of the flowchart shown in FIG.

[0036] As described above in detail, in the first embodiment, in addition to acquiring information on the structural properties and thermal properties of the first member 101 and the second member 102 and information on the thermal properties of the air layer formed at the contact interface between the first member 101 and the second member 102, the actual contact points 131 scattered at the contact interface between the first member 101 and the second member 102 are also acquired. -i Each diameter D i The overall thermal contact resistance R of the contact interface is calculated using the formula (6) with the information obtained as a variable. th We try to calculate the following.

[0037] According to the first embodiment configured as described above, the first member 101 and the second member 102 come into contact with each other with a high contact pressure, and the actual contact points 131 scattered throughout the contact area -i Unlike the estimation formula of Tachibana and Sanogawa, which assumes that the magnitude of the contact pressure does not fluctuate, the first member 101 and the second member 102 come into contact with each other at a lower contact pressure, and multiple actual contact points 131 scattered on the contact interface are generated. -i The overall thermal contact resistance R of the contact interface is calculated using a formula that corresponds to the case where the magnitude of th As a result, even when the first member 101 and the second member 102 come into contact with each other at a contact pressure lower than that assumed by the Tachibana-Sanogawa estimation formula, the contact thermal resistance R th can be estimated more accurately.

[0038] In the first embodiment, the thermal contact resistance R is calculated by the formula (6). th However, the present invention is not limited to this. For example, the contact thermal resistance R can be calculated by the following simplified formula (Formula 9): th This also applies to the second embodiment described below. (Equation 9) is the actual contact point 131 in (Equation 6). -i Thermal resistance r th-ri is omitted, and the actual contact point 131 of the first member 101 -i Thermal resistance r due to the reduction of heat flow to th-coni and the thermal resistance r of the air layer 140 th-air and the actual contact point 131 of the second member 102. -i Thermal resistance r due to expansion of heat flow from th-spi This is the formula for calculating the combined resistance.

[0039]

number

[0040] Figure 9 shows the thermal contact resistance R calculated using equation (9). th This accuracy verification was also performed under the same conditions as the model shown in FIG. 7, and the contact thermal resistance R calculated by the simplified formula (Equation 9) for models with different combinations of parameters was th and the thermal contact resistance R obtained by simulation. th_sim As shown in Figure 9, the contact thermal resistance R th ,R th_sim The plots are concentrated near the solid line that indicates the matching of the thermal contact resistance R th It was confirmed that the prediction was accurate.

[0041] Also, the contact pressure is p m , Vickers hardness H ν Then, the total area A of the contact interface and the actual contact point 131 -i Total area of ​​Σa iBy utilizing the relationship shown in the following (Equation 10) between the total area A and the Vickers hardness H ν and the actual contact point 131 -i Total area of ​​Σa i The contact pressure p m This also applies to the second embodiment described next.

[0042]

number

[0043] (Second embodiment) Next, a second embodiment of the present invention will be described with reference to the drawings. Fig. 10 is a block diagram showing an example of the functional configuration of a contact thermal resistance estimation device 10' according to the second embodiment. In Fig. 10, components with the same reference numerals as those in Fig. 1 have the same functions, and therefore redundant explanations will be omitted here.

[0044] 10, a contact thermal resistance estimation device 10′ according to the second embodiment includes, as functional components, a first information acquisition unit 11′, a second information acquisition unit 12′, and a contact thermal resistance calculation unit 13. More specifically, the first information acquisition unit 11′ includes, as functional components, a surface texture data acquisition unit 11c, a texture data analysis unit 11d, and an actual contact point estimation unit 11e.

[0045] The second information acquisition unit 12′ acquires, from among the physical property information described in the first embodiment, the total area A of the contact interface, the thermal conductivity λ1 of the first member 101, the thermal conductivity λ2 of the second member 102, and the thermal conductivity λ of the air layer 140. air In addition, the second information acquiring unit 12′ acquires the contact pressure p m and Vickers hardness H ν The second information acquisition unit 12′ acquires the total area A of the contact interface and the thermal conductivities λ1, λ2, λ airis output to the contact thermal resistance calculation unit 13, and the total area A of the contact interface, the contact pressure p m and Vickers hardness H ν The information is output to the actual contact point estimation unit 11e.

[0046] The surface texture data acquisition unit 11c acquires texture data of each surface of the first member 101 and the second member 102. This surface texture data acquisition unit 11c acquires texture data of each surface that will come into contact between the first member 101 and the second member 102, rather than texture data of the contact interface when the first member 101 and the second member 102 are actually brought into contact with each other. For example, the surface texture data acquisition unit 11c acquires the texture data of each surface using a laser microscope.

[0047] The property data analysis unit 11d analyzes the property data of each surface acquired by the surface property data acquisition unit 11c (image data obtained by capturing images of the surfaces of the first member 101 and the second member 102 using a laser microscope) to acquire information about the mechanical properties of the first member 101 and the second member 102. Here, the property data analysis unit 11d acquires height information about each surface of each member 101, 102 as information about structural properties. The height information acquired by the property data analysis unit 11d is information that indicates the height of a portion that is convex relative to the height of a reference point set on the surface of each member 101, 102.

[0048] FIG. 11 is a diagram for explaining this height information. FIG. 11 schematically shows cross sections of a first member 101 and a second member 102. In the example of FIG. 11, the property data analysis unit 11d acquires height information h1 indicating the height of a portion that is convex relative to the height of the reference point Q1, using the four corners of the surface of the first member 101 as reference points Q1. The property data analysis unit 11d acquires this height information h1 for each surface position of the first member 101. Acquiring for each surface position means acquiring information for all pixels of the image data or for every few pixels. Similarly, the property data analysis unit 11d acquires height information h2 indicating the height of a portion that is convex relative to the height of the reference point Q2, using the four corners of the surface of the second member 102 as reference points Q2, for each surface position of the second member 102. Note that, hereinafter, if a plane perpendicular to the directions of the heights h1 and h2 is considered to be an xy plane, the height information h1 and h2 for each surface position will be calculated as h1. -xy +h2 -xy This is written as (x=0,1,2,···, y=0,1,2,···).

[0049] The property data analysis unit 11d analyzes the height information h1 acquired for each surface position of the first member 101. -xy The property data analysis unit 11d calculates the average value of the height information h2 obtained for each surface position of the second member 102 and outputs it to the contact thermal resistance calculation unit 13 as height information δ1 indicating the surface roughness of the first member 101. -xy The average value of these values ​​is calculated and output to the contact thermal resistance calculation unit 13 as height information δ2 indicating the surface roughness of the second member 102.

[0050] The actual contact point estimation unit 11e uses the information on the mechanical properties acquired by the property data analysis unit 11d (height information h1 for each surface position of the first member 101) -xy and height information h2 for each surface position of the second member 102 -xy ), actual contact points 131 that will be scattered on the contact interface when the first member 101 and the second member 102 are brought into contact with each other are calculated. -i Each diameter D -i The actual contact point estimation unit 11e estimates the diameter D-i The method for estimating will be described in detail with reference to FIG. 11 mentioned above and FIG. 12 shown below.

[0051] 11 above shows a state in which the first member 101 and the second member 102 are virtually arranged to face each other (not in contact). When the first member 101 and the second member 102 are brought closer together from this state, the first member 101 and the second member 102 eventually come into contact with each other. At this time, the first member 101 and the second member 102 have surface roughness, so there are multiple actual contact points 131. -i Make local contact with the

[0052] Here, if the distance between the reference point Q1 of the first member 101 and the reference point Q2 of the second member 102 is G, the gap length H for each surface position between the surface of the first member 101 and the surface of the second member 102 is -xy is H -xy =G-(h1 -xy +h2 -xy ) and at a certain pixel position P -xy In the gap length H -xy When the first member 101 and the second member 102 approach each other until the pixel position P -xy The first member 101 and the second member 102 come into contact with each other at a plurality of pixel positions P -xy Each of the blocks has a real contact point 131 -i is equivalent to

[0053] Just H -xy = 0 pixel position P -xy So, the contact pressure p m is approximately zero, and the first member 101 and the second member 102 are in contact with each other. -xy <0 pixel position P -xy So, the contact pressure p m is greater than zero, and the surface of at least one of the first member 101 and the second member 102 is deformed and in contact with each other. m The larger the value, the larger the deformation of the surface.-i Area D i The degree of deformation depends on the contact pressure p between the first member 101 and the second member 102. m and Vickers hardness H ν by.

[0054] FIG. 12 shows the gap length H between the first member 101 and the second member 102. -xy Actual contact point 131 that occurs according to -i 12(a1) to 12(a3) are diagrams for explaining the gap length H -xy For the sake of simplicity, the pixel positions P -xy Gap length H -xy The horizontal axis represents the pixel position P -xy , the vertical axis is the gap length H -xy For ease of understanding, the gap length H -xy The change in the gap length H -xy The actual contact point 131 occurs when the state of Fig. 12(a1) to (a3) ​​is -i is shown schematically.

[0055] Figure 12(a1) and (b1) show that the contact pressure p m By giving multiple pixel locations P -xy The longest gap length H -xy The pixel position P -xy Only in H -xy <0, that is, the first member 101 and the second member 102 form one actual contact point 131. -1 Figures 12(a2) and (b2) show the state where the contact pressure is larger than p m By applying the force, the first member 101 and the second member 102 are brought closer to each other and come into contact with each other, and the first member 101 and the second member 102 form two actual contact points 131. -1 ,131 -2 Figure 12(a3) and (b3) show the state where the contact pressure is even larger, p mBy applying the force, the first member 101 and the second member 102 are brought closer to each other and come into contact with each other, and the first member 101 and the second member 102 are brought into contact with each other at three actual contact points 131. -1 ~131 -3 indicates the contact state.

[0056] The actual contact point estimation unit 11e calculates the gap length H for each surface position while giving the value of the distance G between the first member 101 and the second member 102 as a variable. -xy Depending on the actual contact point 131, as shown in Fig. 12(b1) to (b3), -i Then, the generated virtual image is subjected to image analysis similar to that performed by the property data analysis unit 11b described in the first embodiment, thereby detecting actual contact points 131 scattered on the virtual image. -i Each diameter D i information on the actual contact points 131 -i The total area of ​​Σa i Since this is a virtual total area, Σa i-sim I will write it as follows.

[0057] On the other hand, the actual contact point estimation unit 11e calculates Σa i =p m A / H ν Based on the actual contact point 131 -i The total area of ​​Σa i This is calculated based on the contact pressure p when the first member 101 and the second member 102 are actually brought into contact with each other. m , Vickers hardness H ν and the total area A is substituted and the actual total area is calculated, so Σa i-rel The actual contact point estimation unit 11e calculates the actual contact point Σa i-sim =Σa i-rel If they do not match within a predetermined error tolerance, the value of the distance G is changed and the same process is repeated. i-sim =Σa i-rel The actual contact point 131 obtained when -i Diameter D iThe information is output to the contact thermal resistance calculation unit 13 as an estimation result.

[0058] The contact thermal resistance calculation unit 13 calculates the height information δ1 and δ2 indicating the surface roughness of the first member 101 and the second member 102 provided by the property data analysis unit 11d, and the actual contact point 131 provided by the actual contact point estimation unit 11e. -i Diameter D i , and the total area A of the contact interface provided by the second information acquisition unit 12′, the thermal conductivity λ1 of the first member 101, the thermal conductivity λ2 of the second member 102, and the thermal conductivity λ of the air layer 140. air Using the formula (6) or (9), the total thermal contact resistance R of the contact interface is calculated. th Calculate.

[0059] 13 is a flowchart showing an example of operation of the contact thermal resistance estimation device 10′ according to the second embodiment (a processing example of the contact thermal resistance estimation method). As shown in FIG. 13, the second information acquisition unit 12′ acquires physical property information (the total area A of the contact interface and the thermal conductivities λ1, λ2, λ air ) and contact pressure p m and Vickers hardness H ν The second information acquisition unit 12′ acquires the total area A of the contact interface and the thermal conductivities λ1, λ2, λ air is output to the contact thermal resistance calculation unit 13, and the total area A of the contact interface, the contact pressure p m and Vickers hardness H ν The information is output to the actual contact point estimation unit 11e.

[0060] Next, the surface property data acquisition unit 11c of the first information acquisition unit 11' acquires property data of each surface of the first member 101 and the second member 102 (step S12). Next, the property data analysis unit 11d acquires height information h1 of each surface of each member 101, 102 as information on the mechanical properties of the first member 101 and the second member 102. -xy ,h2 -xyThe property data analysis unit 11d acquires the height information h1 acquired for each surface position of the first member 101 and the second member 102 (step S13). -xy ,h2 -xy The average values ​​of the heights δ1 and δ2 are calculated and output to the contact thermal resistance calculation unit 13 as height information δ1 and δ2 indicating the surface roughness (step S14).

[0061] Thereafter, the actual contact point estimation unit 11e calculates the height information h1 obtained in step S11 and the height information h1 obtained in step S13. -xy ,h2 -xy By performing the following steps S15 to S19 using the above, actual contact points 131 that will be scattered on the contact interface when the first member 101 and the second member 102 are brought into contact with each other are obtained. -i Each diameter D -i Estimate the information.

[0062] That is, the actual contact point estimating unit 11e first sets an arbitrary value as the distance G between the first member 101 and the second member 102 (step S15). Then, the actual contact point estimating unit 11e calculates the distance G and the height information h1 -xy ,h2 -xy The gap length H for each surface position is calculated based on -xy 131 one or more actual contact points depending on -i By generating a virtual image in which the real contact points 131 exist, and analyzing the virtual image, the real contact points 131 scattered on the virtual image are detected. -i Each diameter D i (Step S16). Furthermore, the actual contact point estimation unit 11e acquires information on one or more actual contact points 131. -i Diameter D i Based on the information, 131 actual contact points -i The hypothetical total area of ​​Σa i-sim is calculated (step S17).

[0063] The actual contact point estimation unit 11e also estimates the contact pressure p m , Vickers hardness H ν Based on the total area A, the actual contact point 131 -iThe actual total area of ​​Σa i-rel (Step S18). Then, the actual contact point estimating unit 11e calculates the virtual total area Σa calculated in Step S17. i-sim and the actual total area Σa calculated in step S18 i-rel It is determined whether or not they match (step S19). If they do not match, the process returns to step S15, the distance G is set to another value, and the processes of steps S16 to S19 are executed again.

[0064] On the other hand, the hypothetical total area Σa i-sim and the actual total area Σa i-rel If it is determined that the actual contact point 131 calculated in step S16 at that time matches the actual contact point 131, the actual contact point 131 is calculated as the actual contact point 131. -i Diameter D i The information is output as an estimation result to the contact thermal resistance calculation unit 13 (step S20). Thereafter, the contact thermal resistance calculation unit 13 calculates the physical property information acquired by the second information acquisition unit 12′ in step S11, the height information δ1 and δ2 indicating the surface roughness calculated in step S14, and the actual contact point 131 output from the actual contact point estimation unit 11e in step S20. -i Diameter D i The overall thermal contact resistance R of the contact interface is calculated using the formula (6) or (9) with the variables th (Step S21) This completes the process of the flowchart shown in FIG.

[0065] In the second embodiment described above in detail, as in the first embodiment, the first member 101 and the second member 102 are contacted at a plurality of actual contact points 131 scattered on the contact interface by a contact pressure lower than the contact pressure assumed by the Tachibana-Sanogawa estimation formula. -i The total thermal contact resistance R of the contact interface is calculated using a formula that corresponds to the case where the contact is localized at th As a result, even when the first member 101 and the second member 102 come into contact with each other at a contact pressure lower than that assumed by the Tachibana-Sanogawa estimation formula, the contact thermal resistance R th can be estimated more accurately.

[0066] Furthermore, according to the second embodiment, there is no need to acquire property data of the contact interface when the first member 101 and the second member 102 are actually in contact with each other, and it is only necessary to acquire property data of the surfaces of the first member 101 and the second member 102, which has the advantage that the property data is easy to obtain.

[0067] In the first and second embodiments, both the first member 101 and the second member 102 have minute surface roughness. However, the present invention can also be applied to cases where only one of the members has minute surface roughness and the other member has a flat surface. For example, the present invention can be applied to cases where a high-hardness material with minute surface roughness, such as ceramics, comes into contact with a low-hardness material, such as aluminum, whose surface has been flattened by surface processing. In this case, the calculation formula can be applied by setting either the surface height δ1 of the first member 101 or the surface height δ2 of the second member 102 to zero.

[0068] Furthermore, the above-described embodiments are merely examples of specific embodiments for carrying out the present invention, and the technical scope of the present invention should not be construed as being limited thereby. In other words, the present invention can be carried out in various forms without departing from the gist or main characteristics thereof. [Explanation of symbols]

[0069] 10,10' Contact thermal resistance estimation device 11,11' First information acquisition unit 11a Interface property data acquisition section 11b Property Data Analysis Section 11c Surface texture data acquisition section 11d Property Data Analysis Section 11e Actual contact point estimation unit 12,12' Second information acquisition unit 13 Contact thermal resistance calculation section 101 First member 102 Second member 131 -i Actual contact point

Claims

1. An apparatus for estimating contact thermal resistance at a contact portion where a first member and a second member contact each other, comprising: an information acquisition unit that acquires information on the diameters of the actual contact points scattered on the contact interface between the first member and the second member, information on the structural properties and thermal properties of the first member and the second member, and information on the thermal properties of an air layer formed on the contact interface between the first member and the second member; a contact thermal resistance calculation unit that calculates the overall contact thermal resistance of the contact interface by a calculation formula that uses the information acquired by the information acquisition unit as a variable, the information on the structural properties is information on the total area of ​​the contact interface between the first member and the second member and the total area of ​​the actual contact points, a height indicating the surface roughness of the first member, and a height indicating the surface roughness of the second member; the information on the thermal properties is information on the thermal conductivity of the first member and the thermal conductivity of the second member; The information about the thermal properties of the air layer is information about the thermal conductivity of the air layer. A contact thermal resistance estimation device characterized by:

2. The contact thermal resistance estimation device described in Claim 1, characterized in that the information acquisition unit acquires information on Vickers hardness and contact pressure when the first member and the second member are actually brought into contact, instead of the overall area and the total area of ​​the actual contact points.

3. The information acquisition unit an interface property data acquisition unit that acquires property data of the contact interface when the first member and the second member are actually brought into contact with each other; a property data analysis unit that analyzes the property data of the contact interface acquired by the interface property data acquisition unit to acquire information on the diameters of the actual contact points scattered on the contact interface.

3. The device for estimating contact thermal resistance according to claim 1 or 2.

4. The information acquisition unit a surface texture data acquisition unit that acquires texture data of each of the surfaces of the first member and the second member; a property data analysis unit that analyzes the property data of each of the surfaces acquired by the surface property data acquisition unit to acquire height information of each of the surfaces of the first member and the second member relative to a reference point as information regarding the mechanical properties of the first member and the second member; an actual contact point estimating unit that estimates information on the diameters of the actual contact points that will be present on the contact interface when the first member and the second member are brought into contact with each other, based on information on the mechanical properties acquired by the property data analyzing unit.

2. The device for estimating contact thermal resistance according to claim 1.

5. The information acquisition unit further acquires information on the contact pressure and Vickers hardness when the first member and the second member are actually brought into contact with each other, The contact thermal resistance estimation device of claim 4, characterized in that the actual contact point estimation unit generates a virtual image in which one or more actual contact points exist according to a gap length between each surface at each surface position calculated based on the distance between the first member and the second member and height information of each surface relative to a reference point, while giving the distance between the first member and the second member as a variable, acquires diameter information for each of the actual contact points by analyzing the virtual image, determines whether the virtual total area of ​​the actual contact points calculated from the acquired diameter information matches the actual total area of ​​the actual contact points calculated based on information on the contact pressure, the Vickers hardness, and the total area of ​​the contact interface, and outputs the diameter information for each of the actual contact points as an estimation result when they match.

6. A contact thermal resistance estimation device as described in any one of claims 1 to 5, characterized in that the calculation formula is a calculation formula that expresses the thermal resistance due to the reduction of heat flow to the actual contact point of the first member and the thermal resistance due to the expansion of heat flow from the actual contact point of the second member using variable values ​​with information acquired by the information acquisition unit as variables.

7. The contact thermal resistance estimation device described in claim 6, characterized in that the calculation formula is a calculation formula for calculating a combined resistance of the thermal resistance due to the reduction of heat flow to the actual contact point of the first member, the thermal resistance of the actual contact point, the thermal resistance of the air layer, and the thermal resistance due to the expansion of heat flow from the actual contact point of the second member.

8. The contact thermal resistance estimation device described in claim 6, characterized in that the calculation formula is a calculation formula for calculating a combined resistance of the thermal resistance due to the reduction of heat flow to the actual contact point of the first member, the thermal resistance of the air layer, and the thermal resistance due to the expansion of heat flow from the actual contact point of the second member.

9. A method for estimating thermal contact resistance at a contact portion where a first member and a second member contact each other, comprising: a first step in which an information acquisition unit of a computer acquires information on the diameters of the actual contact points scattered on the contact interface between the first member and the second member, information on the structural properties and thermal properties of the first member and the second member, and information on the thermal properties of an air layer formed on the contact interface between the first member and the second member; a second step in which a contact thermal resistance calculation unit of the computer calculates the overall contact thermal resistance of the contact interface using a calculation formula that uses the information acquired by the information acquisition unit as a variable; the information on the structural properties is the total area or Vickers hardness of the contact interface between the first member and the second member, the total area or contact pressure of the actual contact points between the first member and the second member, the height of convex portions indicating the surface roughness of the first member, and the height of convex portions indicating the surface roughness of the second member; the information about the thermal properties is the thermal conductivity of the first member and the thermal conductivity of the second member; The information about the thermal properties of the air layer is the thermal conductivity of the air layer. A method for estimating contact thermal resistance.

10. A program for causing a computer to execute a process for estimating contact thermal resistance at a contact portion where a first member and a second member are in contact, an information acquiring means for acquiring information on the diameters of actual contact points scattered on the contact interface between the first member and the second member, information on structural properties and thermal properties of the first member and the second member, and information on the thermal properties of an air layer formed on the contact interface between the first member and the second member; and a contact thermal resistance calculation means for calculating the overall contact thermal resistance of the contact interface by a calculation formula using the information acquired by the information acquisition means as a variable; and causing the computer to function as the information on the structural properties is the total area or Vickers hardness of the contact interface between the first member and the second member, the total area or contact pressure of the actual contact points between the first member and the second member, the height of convex portions indicating the surface roughness of the first member, and the height of convex portions indicating the surface roughness of the second member; the information about the thermal properties is the thermal conductivity of the first member and the thermal conductivity of the second member; The information about the thermal properties of the air layer is the thermal conductivity of the air layer. A contact thermal resistance estimation program characterized by:

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