JPH01266479A - Heat transfer joint and manufacture thereof - Google Patents

Abstract

PURPOSE:To produce a heat transfer joint with flexibility and excellent heat-conductive properties, and to facilitate the quality control of the same, by a method wherein a heat transfer member prepared by twisting multiple element wires is provided with a binding terminal which is radially crushed to bind the heat transfer member, and both end surfaces of the bound terminal are flushed, and then a heat transfer piece thus formed is brazed to a flange. CONSTITUTION:First flexible twisted wires made by twisting extra fine element wires are twisted and bound to form second flexible twisted wires 36, and an annular-type bound terminal 38 made of metal is mounted on the flexible twisted wires 36 so as to radially cover both ends 37a of a heat transfer member 37. After the bound terminal 38 is mounted, the heat transfer member 37 is bound by crushing the bound terminal 38 from the external side. The heat transfer member 37 and both end surfaces 33a of the bound terminal 38 are machined and flushed by, for example, a lathe, a milling machine or the like to form a heat transfer piece 33. These pieces are arranged in a state that twelve of them are arrayed in a circumferential shape, and both end surfaces 33a of each of them are brazed and bonded to a pair of flanges 31 and 32 by using a brazing material such as low-temperature solder with high strength and thermal conductivity at a low temperature, thereby forming a heat transfer joint 30.

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a heat transfer joint that transfers heat and a method of manufacturing the same. [Prior Art] For example, in a cryopump, a heat transfer joint for extremely low temperatures is used (see Japanese Utility Model Application Publication No. 167059/1983). In the cryopump described above, a cooling panel housed in a cryogenic container is fixed to the cryogenic cold head of a refrigerator, and the gas (N fi + o l
+Oa) on the surface of the cooling panel, a high vacuum is obtained within the vessel. However, if the cooling panel and the cold head are not sufficiently fixed, the contact thermal resistance between the two will increase, making it impossible to obtain the cooling effect of the cooling panel. Therefore, conventionally, as shown in FIG. A method of rigidly fixing it is used. According to this method, by increasing the tightening force of each bolt 6, the above-mentioned fixation can be strengthened, and by interposing the relatively soft indium sheet 5, both contact portions 3.4 can be tightened. Metal contact can be ensured. Therefore, the contact thermal resistance is reduced, the temperature of the cooling panel 1 can be brought close to the temperature level of the cold head 2, and the cooling effect of the cooling panel 1 is enhanced. Here, Fig. 6 shows a general example of a medium-sized and small-sized cryopump. Inside the casing 12, there is a first cooling panel 10 cooled to 80°K, for example, and a first cooling panel 10 cooled to 15°K.
A second cooling panel 1M, which is cooled by the second cooling panel 1M, is housed therein. The bottom plate portion 10 of the first and second cooling panels 10.11
a, Ila connect each cold head 15.1 of the first and second stage refrigeration sections 13.14 via the indium sheet 5.
6 by the method shown in FIG. 1 above. In other words, in a typical small to medium-sized cryopump, the refrigerator 8 consists of one cylinder and one cold spatula 1-15.
or 16, one cooling panel 10 or 11 is cooled. [Problems to be Solved by the Invention] However, in a large refrigerator having multiple cylinders or a large cryopump having multiple refrigerators,
When cooling a set of cooling panels, if the above-mentioned conventional rigid fixing method is adopted, the following disadvantages arise. Figure 7 shows the thermal contraction of various materials at low temperatures, with the horizontal axis representing the absolute temperature T (K) and the vertical axis representing the coefficient of linear expansion Δ1.
2/12 ('10o・) is taken and shown. Here, for example, assume that the material of the cooling panel is aluminum, which is light and has good thermal conductivity, and that multiple refrigeration panels are arranged at equal intervals on a circumference of 1 m in diameter and rigidly connected to a foundation at room temperature. Assume that an aircraft is cooling a set of first and second stage cooling panels. In this case, when the refrigerator is started with the cold head of the refrigerator and the cooling panel rigidly connected, the first stage cooling panel will be heated from room temperature to 80°K, and the second stage cooling panel will be heated from room temperature to 80°K.
The tiered panels are cooled and contracted from room temperature to 15°K, while each refrigerator fixed to the room temperature foundation maintains its original position, so there is a large relative distance between the cold head and the cooling panel mounting part. Displacement occurs. When the magnitude of the relative displacement is calculated based on the coefficient of linear expansion Δn/fi shown in Figure 7, it reaches approximately 2 mm for both the first stage and the second stage, which causes abnormal stress on the cooling panel and refrigerator. may occur and may even be damaged. Therefore, in such cases, it is necessary to connect the cold head and the cooling panel through a flexible heat transfer joint that absorbs thermal deformation and can transmit a large amount of heat. For a certain number of 0 or more, we have explained the case where multiple refrigerators are arranged on the same circumference, but
A similar problem occurs when a panel is cooled by a single refrigerator having multiple cylinders. moreover. This type of inconvenience also occurs when the heat transfer joint is used in devices other than the Talio pump. Here, the heat transfer member of a flexible heat transfer joint should be thin and long in order for the joint to bend easily (flexible), and conversely, it is better to be thick and short in order for the joint to conduct heat well. . Therefore, the inventor first created a joint by bundling a large number of extremely thin wires made of copper or aluminum, which have good thermal conductivity at low temperatures, and brazing the ends of this bundle to flanges with low-temperature solder or silver. I thought about that. However, when doing this, the molten solder or silver penetrates into the gaps between each thin wire over a considerable length due to capillary action, and the bundle of thin wires solidifies due to this penetrated solder or silver. do. Therefore, the flexibility of the heat transfer member, that is, the heat transfer joint is reduced. Additionally, if the lengths of the thin wires are uneven, a partial space will be created between the end of the bundle and the end of the flange, and this space will be occupied by solder with low thermal conductivity, resulting in heat generation. This will hinder the ease of conveying the information. For example, 2.5% silver
, 97.5% lead cryogenic solder is 20″K (-25
3° C.) is approximately I/20 of the thermal conductivity of copper at that temperature, thus significantly increasing the thermal resistance. Therefore, it is necessary to make both end faces of the bundle flush. As a means for making the surface level, first, a method of cutting thin wires one by one to a predetermined length can be considered. However, in order to obtain the specified dimensional accuracy, it is necessary to increase the wire diameter of the thin wire to a certain degree (for example, 1 mm).
Therefore, the ease with which the heat transfer joint bends decreases. In addition, with the method of solidifying both ends of a thin wire with solder or the like and machining the solidified both end surfaces, both end surfaces cannot be finished flush, and the capillary phenomenon described above also causes problems in heat transfer joints. Ease of bending is low. Furthermore, in the method of cutting a cabtyre cord whose outer periphery at both ends of a bundle is wrapped with rubber or cloth, the ends of each thin wire cannot be made sufficiently rigid, so both ends cannot be finished flush. The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a flexible heat transfer joint that has excellent thermal conductivity and is easily bent, and a method for manufacturing the same. [Means for Solving the Problems] ]-2 In order to achieve the objective, the heat transfer joint of the present invention has the following features:
First, there is a heat transfer member in which a plurality of flexible stranded wires made by twisting together a large number of strands with excellent thermal conductivity are bundled, and both ends of this heat transfer member are covered from the radial direction. and binding terminals that bind the heat transfer members by compressing them in the radial direction. ] Both end surfaces of the heat transfer member and the binding terminal are formed flush with each other, and flanges are brazed to both end surfaces of the flush end surfaces. The heat transfer joint can be used by being inserted between a cooling panel housed in a cryogenic container of a cryopump and a cold head of a refrigerator. In the manufacturing method of the present invention, first, a large number of wires with excellent thermal conductivity are twisted together to form a flexible stranded wire. Next, a plurality of the flexible stranded wires are bundled together, and ring-shaped binding terminals are attached to both ends of the bundled flexible stranded wires.
This binding terminal is crushed from the outside to bundle the bundle of flexible stranded wires. After this binding, both end surfaces of the bundled heat transfer member and binding terminal are processed to be flush with each other to form a heat transfer piece, and further, the flat end surfaces are joined to a pair of flanges by brazing.

[Effect]

According to this invention, the binding terminals covering both ends of the bundle of flexible stranded wires are crushed from the outside to bind the bundle, so that the wires are arranged extremely closely. Therefore, since capillarity is less likely to occur, there is no risk of the brazing material entering between each strand, and as a result, the heat transfer joint becomes flexible. In addition, since both end surfaces of the heat transfer member are formed flush,
Since there are no local gaps between the ends and the flange, the brazing results in a uniform and thin layer of material, and therefore good thermal conductivity. Furthermore, since the length of the wires that are radially restrained by the binding terminals is a predetermined length, the length of the flexible portion of the heat transfer member is constant for each product, making quality control easy. become. Further, according to the manufacturing method of the present invention, after the binding terminals covering both ends of the two bundles are crushed from the outside and the bundles are bound, both end surfaces of the bundles and the binding terminals are applied. , the ends of each strand are sufficiently constrained (made rigid) by the binding end=F. Therefore, since both end surfaces can be easily formed flush with each other, a heat transfer joint with good thermal conductivity can be obtained. [Example] An example of this invention will be described below with reference to the drawings. FIG. 1 shows part of a large cryopump having multiple Stirling cycle refrigerators. In this diagram,
The bottom plate portions 10a, 11a of each cooling panel 10.11 are joined to each cold head 15.16 of a plurality of refrigerators 8.8 via an indium sheet 5 and a heat transfer joint 30. First, the cryopump will be explained. The vacuum chamber 19 and the space 20 within the cryopump casing 12 are, for example, 10-6 to 10-'T. The first and second stage freezing sections 13.14 of the regenerator refrigerator 8 are inserted into the cryopump casing 12.
are the first and second cold heads 15, 16 and the expansion chamber 2.
1.22. The first
and second cold head 15.16 respectively 80
and 15°K. Both of the cooling panels 10.11 are formed into bottomed cylindrical shapes of different sizes. The bottom plate portion 10a of the first cooling panel 10 is provided with a through hole 25 having a diameter larger than the outer diameter of the first stage freezing section 13, and the freezing section 13 is inserted into the through hole 25. A cylindrical adsorption type flannel 23 is provided inside the second cooling panel 11, and an adsorbent 24 such as activated carbon is coated on the inner wall thereof. The adsorbent 24 absorbs Hg in the vacuum chamber 19 and the space 20 inside the Talio pump.
It plays the role of adsorbing and holding Ie gas, etc. In addition, 5
0 is a baffle plate for preventing heat input due to radiation from the vacuum chamber 19 from entering the first cooling panel 10. Next, the heat transfer joint 30 will be explained along with its manufacturing method. The heat transfer joint 30 has a pair of flanges 31.3 in FIG.
2 and is joined to this flange 31 and 32 by brazing,
As shown in FIG. 3, it is composed of 12 heat transfer pieces 33 (only the left half is shown) arranged circumferentially. In order to manufacture the heat transfer joint 30, first, as shown in FIG.
An extremely thin element M (for example, wire diameter 0.06 mm)
34, for example, 278 wires to form the first flexible stranded wire 3.
5 is formed. The wire 34 is made of a material with excellent thermal conductivity, such as copper or aluminum. Next, for example, seven of the first flexible stranded wires 35 are twisted together to form a fourth flexible stranded wire 35.
A second flexible strand (composite strand l; 1) 36 of figure (b) is formed. After this, as shown in FIG. 4(c), the second flexible stranded wire 36 is
For example, 48 sets of wires are bundled together, and an annular metal binding terminal 38 is attached to the bundled second flexible stranded wire 36 (heat transfer member 37a), and both ends 37a of the heat transfer member 37 are connected in the radial direction. Let's cover it. After this attachment, the binding terminal 38 is attached in FIGS.
), by crushing from the outside (inward direction), the bundle of the second flexible stranded wires 36, that is, the heat transfer part jIJi3
Bind 7. After this bundling, both end surfaces 33a of the heat transfer member 37 and the bundling terminal 38 are machined using a lathe or milling machine, for example, to make them flush as shown in FIG. With 12 heat transfer pieces 33 arranged in a circumferential manner as shown in Fig. 3, both ends 33a are connected to a pair of flanges 31 and 32 as shown in Fig. The heat transfer joint 30 is formed by brazing and joining using a material such as low-temperature semi-Ill with good thermal conductivity.Therefore, the heat transfer joint 30 is made of 278 (pieces) x 7 x 48 x 12 = 1. .120,896
(Refer to FIG. 4(a)). ] The flange 31.32 of the bipedal heat transfer joint 30 is attached to the bottom plate portion 10a of each cooling panel 10.11 in FIG. 11a and cold heads 15 and 16 via an indium sheet 5, as in the conventional example shown in FIG. 5, with bolts and nuts. In the above configuration, when the refrigerator 8.8 of FIG. 1 is started, both cooling panels 10.11 are cooled and contracted. In other words, the mounting pitches PI and P2 of the refrigerators 8 on both cooling panels 10.11 become shorter. On the other hand, the pitch P3 of the portion of the refrigerator 8 fixed to the foundation (not shown) at room temperature does not become shorter. On the other hand, in the present invention, the second flexible portion shown in FIG.
Since both ends 37a of the heat transfer member 37 consisting of a bundle of 936 wires are compressed and bundled from the outside by the binding terminals 38, the wires 34 shown in FIG. 4(a) are arranged extremely closely. Therefore, since capillarity is less likely to occur, the brazing material is less likely to penetrate between the individual wires 34, so that the heat transfer member 36 (FIG. 4(r)) made of extremely thin wires 34 becomes flexible. As a result, the pitch PI shown in FIG. 1 above. 1)2. Even if P3 varies relatively, cooling panel 10.
11 and the refrigerator 8 are not subjected to large stress. Moreover, both end surfaces 33a of the heat transfer piece 33 in FIG. 4(f)
are formed flush with each other, so that each end surface 33a and the second
There is no partial gap between the flanges 31 and 32 shown. Therefore, each end face 33a and the flange 31.32
Brazing between the parts has excellent thermal conductivity because the material layer is uniform and thin. Further, the length L of the wire 34 (FIG. 4(a)) restrained in the radial direction by the binding terminal 38 in FIG. 4(f) can be set to a predetermined dimension. Therefore, the heat conductive material 37
Since the length Ll of the flexible portion 37b (middle portion) is constant for each product, quality control becomes easier. Further, according to the manufacturing method of the present invention, the binding terminals 38 covering both ends 37a of the heat transfer member 37 are crushed from the outside to bind the heat transfer member 37. Therefore, when processing each end 33a of the heat transfer piece 33, each strand 34
Since the end portions (FIG. 4(a)) are sufficiently restrained (four pieces) by the binding terminals 38, the respective end surfaces 33a can be easily formed flush. Therefore, since brazing makes the material layer uniform and thin, the heat transfer joint 30 shown in FIG. 2 with excellent thermal conductivity can be obtained. By the way, in this invention, the flexible stranded wire includes, in addition to the above-mentioned composite stranded wire, for example, a braided wire made by combining a large number of wires with excellent thermal conductivity into a bag net with a circular or flat cross section. Therefore, the heat transfer member 37 may be constructed by bundling this braided wire. [Effect of the Invention J As explained above, according to the present invention, a heat transfer joint that is flexible, has excellent thermal conductivity, and is easy to control quality can be obtained. Further, according to the manufacturing method of the present invention, each end of the heat transfer member can be easily made flush with each other, and a heat transfer joint with good thermal conductivity can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a fixing structure of a cooling panel and a cold head according to an embodiment of the present invention, FIG. 2 is a partially sectional side view of a heat transfer joint, FIG. 3 is a plan view of the same, and FIG. The figure is a process diagram showing the manufacturing method of a heat transfer joint, and Figure 5 is a sectional view showing details of the conventional cooling panel and cold head fixing structure.
FIG. 6 is a sectional view showing the fixing structure, and FIG. 7 is a characteristic diagram showing the coefficient of linear expansion with respect to temperature. 8... Refrigerator, 10.11-... Cooling panel, 15° 6... Cold head, 30-... Heat transfer joint, 31
゜32--Flange, 33--Heat transfer piece, 33a
- (Both) end faces, 34 - Element wire, 36 - (Second) flexible stranded wire, 37 - Heat transfer member, 37a... (Both) ends, 38 - Binding terminal. Figure 1 8: Ling Tan Machine Figure 2 Figure 3 Figure 4 Figure 5

Claims (3)

[Claims] (1) A heat transfer member in which a plurality of flexible stranded wires made by twisting a large number of wires with excellent thermal conductivity are bundled, and both ends of this heat transfer member are covered from the radial direction, and the heat transfer member is A bundling terminal for bundling the heat transfer member by crushing the member in a radial direction, wherein both end surfaces of the heat transfer member and the bundling terminal are flush with each other, and flanges are brazed to both flush end faces. A heat transfer joint. (2) A heat transfer joint according to claim (1), which is inserted between a cooling panel housed in a cryogenic container of a cryopump and a cold head of a refrigerator. (3) The process of twisting together a large number of wires with excellent thermal conductivity to form a flexible stranded wire, and bundling a plurality of these flexible stranded wires, and forming a ring at both ends of the bundled flexible stranded wire. Attach the binding terminal, press the binding terminal from the outside, and
A step of bundling the bundle of flexible stranded wires, a step of forming a heat transfer piece by processing both end faces of the bundled heat transfer member and the bundling terminal to make them flush, and a step of forming a pair of both end faces of the said coplanar wires. A method for manufacturing a heat transfer joint, comprising the step of joining the flange of the heat transfer joint by brazing.