JPS63128793A - Method of improving heat absorption capability of cold plate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to the heat absorption capacity of a cold plate provided to absorb heat generated from transformers, power transistors, etc. in space equipment such as spacecraft and artificial hygiene. It is about how to improve.

<Prior art> Since space is a vacuum and there is no gravity, heat transfer through air convection cannot be expected. Furthermore, the place where heat is radiated is outer space, and ultimately it must be through thermal radiation.

Therefore, a means is required to transfer heat from a heat generating element such as a transformer to a radiator provided in an exposed manner outside the space equipment, and a cold plate is provided as one means for this heat transfer.

Currently, cold plates shown in FIGS. 2 and 3 are being considered.

A pipe 2 for inflowing a refrigerant such as water or Freon is connected to one end of a hollow flat cold plate 1, and a pipe 3 for outflow is connected to the other end. Further, inside the cold plate 1, fins 4 are provided which also serve to form a flow path. The refrigerant is circulated between the radiator and the cold plate by a pump (not shown).

Heat from a heating element 5 such as a transformer or a power transistor is thermally conducted to the cold plate 1.
The heat is transferred to the refrigerant flowing inside, and the heat of the refrigerant is radiated into space by a radiator.

Generally, the method of attaching the heating element 5 to the cold plate is to bring the heating element 5 into direct contact with the cold plate, and then use fasteners such as bolts that pass through numerous bolt holes 6 drilled in the cold plate 1. It's stuck. Therefore, heat transfer between the heating element 5 and the cold plate 1 is carried out through mechanical contact between the two, and the heat transfer coefficient between the two is determined by the effective contact surface where the two are in close contact with each other without any gaps. It is greatly influenced by the ratio.

Conventionally, in order to reduce the thermal resistance at the contact surface between the heating element 5 and the cold plate 1, consideration has been given to increasing the contact pressure by tightening the bolt with a wrench driven by a motor or the like.

<Problems to be Solved by the Invention> However, in the above-mentioned mounting method, the contact surface where heat transfer occurs effectively is limited to the area around the bolt, and therefore the effective contact area must be increased to obtain the desired heat transfer. , the number of bolts must be greatly increased, which increases the weight of the entire device (which leads to an increase in the cost of launching a spacecraft, etc.), and depending on the type of heating element 5, the number of mounting bolts may not be too large. In some cases, it may not be possible to increase the number of bolts, and it must be taken into consideration that increasing the number of bolts may impede the flow of refrigerant within the cold plate.

<Objective of the Invention> The present invention was devised in view of the above problems, and provides a method for improving the heat absorption ability of a cold plate by interposing a soft metal on the contact surface to increase the effective contact area. The purpose is to

<Means for Solving the Problems> In order to achieve the above object, the method for improving the heat absorption capacity of a cold plate of the present invention provides at least one of the contact surfaces of the cold plate with the heating element and the contact surface of the heating element with the cold plate. It is characterized in that a soft metal of a required thickness is attached to one of the two to increase the effective contact area where heat transfer is effectively carried out.

<Function> Since soft metal such as gold is attached to one or both of the contact surfaces by plating or vapor deposition, if the heating element and cold plate are strongly tightened with bolts, etc., the surface of the soft metal will deform and cause them to touch each other. Since it makes good contact with the other contact surface, the effective contact area increases, the heat transfer rate improves, and the heat absorption ability of the cold plate improves.

Embodiments The method for improving the heat absorption capacity of a cold plate according to the present invention will be described below with reference to the drawings. FIG. 1 is a drawing embodying the method of improving the heat absorption capacity of a cold plate according to the present invention. In the figure, 1 is a cold plate, 5 is a heating element, 6 is a through bolt hole, 7 is a bolt with a nut, and 10 is an attached soft metal. Consisting of 10b.

The soft metal 10 is a metal such as gold or lead, and has a value of 0.01 to 0.5n+
It is vapor deposited or plated to a thickness of m.

Next, the effect will be explained.

Generally, the surfaces of the cold plate 1 and the heating element 5 are not completely flat, but have slight irregularities, and are also slightly deformed when tightened with bolts and nuts. Therefore, between two contact surfaces, the ratio of the area of the effective contact surface that is in perfect contact to the total contact surface is relatively small. Since a small gap exists in areas other than the effective contact surface and the heat transfer resistance is extremely large, most of the heat transfer from the heating element 5 to the cold plate 1 is performed through the effective contact surface.

According to the invention, the heating element 5 and the cold plate 1
and are tightened by bolts 7 with nuts, and the surfaces of the soft metal 10 adhering to each other's contact surfaces are deformed and come into close contact with each other's contact surfaces, increasing the effective contact area and improving the heat transfer coefficient. The heat absorption capacity of the cold plate 1 will be improved.

Note that the soft metal may be attached to either the contact surface of the cold plate 1 or the contact surface of the heating element 5. Furthermore, the heat generating element 5 may be attached to the cold plate 1 by using a jig (not shown) or the like that sandwiches the two, without providing the through holes 1 and 6 in the cold plate.

<Effects of the Invention> The method for improving the heat absorption capacity of a cold plate according to the present invention has the following effects.

(1) By attaching soft metal to the contact surface of the cold plate and/or the heating element, the heat absorption ability of the cold plate is improved, the contact area can be reduced, and the weight of the entire device is reduced, making it easier for spacecraft. Launch costs will be reduced by 11%.

■ The number of mounting bolts and nuts can be reduced, reducing the burden on executives.

[Brief explanation of the drawing]

FIG. 1 is a drawing embodying the method of improving the heat absorption capacity of a cold plate according to the present invention, FIG. 2 is a plan view of a conventional cold plate, and FIG. 3 is a cross-sectional view taken along the line -■ in FIG. 1...Cold plate 5...Heat generating body 10...Soft metal agent attached to the contact surface Patent attorney Yoshiaki Shimamura. H, -1', Figure 1, Figure 2, Figure 3

Claims (1)

[Claims] A soft metal of a required thickness is attached to at least one of the contact surface of the cold plate with the heating element and the contact surface of the heating element with the cold plate, so as to increase the effective contact area where heat transfer occurs effectively. A method for improving the heat absorption capacity of a cold plate, characterized by: