JPS6152396B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a method of processing an end portion of a pipe, which is a component of a heat transfer device that utilizes the evaporation-condensation action of a liquid.

[Prior art]

Figure 1 is a configuration diagram of a conventional heat transfer device, and Figure 2 is a diagram showing the processing method for the pipes that make up the device (Japanese Patent Application Laid-open No. 56-151888, Japanese Patent Application Laid-open No. 53-54344). 1 (for example, copper or aluminum) and an end portion 1a obtained by drawing one end of the pipe 1 into a spherical shape.
It is composed of a thin nozzle 4 for liquid sealing attached to the. The thin nozzle 4 has a brazing material 7 on the terminal portion 1a.
It is welded using. Further, the end portion 1b on the opposite side of the pipe 1 is also drawn into a spherical shape, and the remaining hole in the center portion is sealed with a brazing material 6. After exhausting the air in the pipe 1 through the narrow nozzle 4 using a vacuum pump, evaporative liquid 3 (for example, water, alcohol, fluorocarbon, etc.) is injected, and the end of the narrow nozzle 4 is caulked to fill the brazing material 5. Weld and seal. The heat transport action of this heat transfer device is performed as follows. When heat is applied to one end of the pipe 1, the liquid 3 inside the pipe 1 receives the heat and evaporates, and the generated steam flows through the pipe 1 due to the vapor pressure difference.
through the internal central vapor space toward the other end. The steam that reaches the other end is cooled, releases latent heat of condensation, and liquefies. This liquid 3 is returned to its original state by gravity or by the capillary force of the groove 2 attached to the inner wall of the pipe 1, and the same cycle as before is repeated. On the other hand, the heat of condensation released at the other end is removed from the outer surface of the pipe 1 by convection of air and water. Since this heat transfer device utilizes the evaporation-condensation effect of the liquid 3, it is possible to transport a large amount of heat from one end of the pipe 1 to the other end with a small temperature difference. When manufacturing this heat transfer device, it is important to prevent the liquid 3 from leaking to the outside, or to prevent air from entering from the outside and reducing the evaporation-condensation effect of the liquid 3. It is to be. For this purpose, it is important to make the holes in the portions sealed using the brazing materials 6 and 7 smaller and to reduce pinholes that are likely to occur in the brazing materials 6 and 7. Spherical processing of the end portions 1a and 1b of the pipe 1, which is a raw material, is performed by adding the pipe 1 to the chuck of a lathe and rotating it, and applying rollers 8 to the end portions, as shown in Fig. 2.
Press and squeeze to create a spherical shape. On this occasion,
As shown in FIG. 3, the end portion 1b or 1a is constricted, so it is thicker than the main body of the pipe 1.
As the processing progresses, the thickness of the terminal parts 1b and 1a increases, and moreover, those parts become work hardened.
The remaining hole 1' will not become small enough. Further, when the groove 2 is cut on the inner surface of the pipe 1, stress concentration may occur in the groove 2' portion of the narrowed end portion 1b, and cracks may occur.

[Purpose of the invention]

The present invention improves the above-mentioned drawbacks, facilitates drawing of the end of the pipe, reduces the diameter of the remaining hole, and prevents cracks from occurring. The purpose of the present invention is to obtain a heat transfer device that is highly reliable and has a good shape after finishing.

[Summary of the invention]

The gist of the present invention is that, prior to processing the end portion of a pipe for a heat transfer device into a spherical shape, a portion of the end portion is thin-walled into a stepped shape or a tapered shape in three or more steps. .

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 4 to 10.

FIG. 4 is a diagram showing an example of a method of processing a pipe for a heat transfer device of the present invention, and FIG. 5 is a diagram showing the configuration of the heat transfer device of the present invention. A groove 2 is provided on the inner surface of the pipe 1 except for the end portions 1a and 1b. That is, the inner surfaces of the end portions 1a and 1b of the pipe 1 are thinned by cutting using a lathe or the like. If the walls are made thin in this way, the terminal parts 1a and 1b can be
does not thicken when squeezed. This makes the drawing process extremely easy, and the diameter of the remaining hole becomes smaller.
The amount of brazing is reduced. Terminal 1 of pipe 1
When the inner surfaces of a and 1b are thinned, a part of the groove 2 on the inner surface may be left as shown in FIG. 6, but the groove 2 is not left as shown in FIG. It's even better from the point of view of stress concentration to remove them all. In addition, when the grooves 2 are not left at both ends of the pipe 1 and the surface is made smooth as shown in FIG. When attaching the tube to the tube and sealing the other end of the pipe 1 with brazing material, the brazing material will no longer flow inside and spread to the inner surface due to the capillary force of the groove, filling the groove. .

When thinning both ends of the pipe 1 like this, it is more effective to make it into a stepped shape with three or more steps as shown in Figures 8 and 9, or a tapered shape as shown in Figure 10. It increases. That is, in these cases, the thickness of the end portions 1a and 1b becomes uniform, the workability is good, and the shape after finishing is also good.

In the above embodiments, the pipes have grooves on the inner surface, but the present invention can also be applied to a smooth pipe without grooves on the inner surface of the pipe.

As explained above, according to the present invention, the workability of spherical drawing of the pipe end portion is improved, and
Since the diameter of the remaining hole after spherical processing can be made small, the amount of brazing is reduced, the proportion of pin poles is reduced, reliability is increased, and a heat transfer device with a good finished shape can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a conventional heat transfer device, Figs. 2 and 3 are diagrams showing an example of a method of processing a pipe for a conventional heat transfer device, and Fig. 4 is a diagram of a pipe for a heat transfer device of the present invention. FIG. 5 is a diagram showing an example of the processing method. FIG. 5 is a configuration diagram of the heat transfer device of the present invention. FIGS. FIG. 1...Pipe, 2...Groove, 3...Liquid, 4...
Fine nozzle, 5, 6, 7... brazing metal, 8... roller.

Claims (1)

[Claims] 1. In the production of a heat transfer device in which an evaporative liquid is sealed inside a sealed pipe, the inner surface of the end portion of the material pipe is thin-walled into a stepped or tapered shape in three or more steps, and then the thin-walled processing is performed. A method for manufacturing a terminal part of a heat transfer device, in which the terminal part is processed into a spherical shape using a spherical processing machine.