JPS5918630B2 - Heat pipe manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a heat pipe that facilitates sealing of the tube end.

As shown in FIG. 1, a conventional heat pipe is constructed by soldering caps 2 and 2' to both ends of a metal tube 1, and then removing air from the inside through an insertion hole 3 made in one of the caps 2. Next, after injecting the working fluid 4 from here, it was manufactured by sealing with a brazing material 8.

However, in the manufacturing method described above, when the caps 2, 2' are fitted onto the ends of the metal tube 1 and these parts are soldered, the length of the wax becomes long, which tends to cause pinholes and leaks. Furthermore, since grooves or wicks that promote the return of the working fluid cannot be provided on the inner surfaces of the caps 2, 2', there is a problem in that the amount of heat transported is small.

Furthermore, when inserting the fin into the heat pipe, the outer surface of the tube end, which has been enlarged by fitting the caps 2 and 2', must be finished by cutting, which has the disadvantage of complicating the manufacturing process. there were.

In view of the above, the present invention was developed as a result of various researches. After inserting a bar-shaped brazing material into one end of a metal tube, drawing the end of the metal tube to clamp the brazing material, and then heating this part. A method of manufacturing a heat pipe has been discovered, which is characterized in that a working fluid is injected into the interior from the other end of the metal tube which is brought into contact with solder and then opened, and the open end is sealed under reduced pressure.

The present invention will be explained below according to the steps.

First, as shown in FIG. 2, a metal tube 1 made of copper, aluminum, stainless steel, or a combination of these materials, which has been previously degreased and pickled, is attached to the tip of the rotating shaft 6 of a drawing machine.

Next, after attaching the bar-shaped brazing material 8 to the brazing material support 7, the supporting material 7 is moved and the tip of the brazing material 8 is attached to the metal tube 1.
Insert it into the end of the

Next, while rotating the rotating shaft 6 of the drawing machine and rotating the brazing material support 7, the spatula 9 is pressed against the end of the metal tube 1, and the rod-shaped brazing material 8 is pressed as shown in FIG. While pinching, perform the drawing process to form a hemispherical shape.

Next, after cutting the rod-shaped brazing material 8 supported by the brazing material support 7, the sandwiched brazing material 8 is heated with a banner and soldered to seal the end of the metal tube 1, as shown in FIG.

In this way, a wick 1 such as a wire mesh or metal fiber that acts as a capillary from the open end of the metal tube 1 whose one end is sealed.
0, a cap 12 having a protruding thin tube 11 is fitted into the open end together with a ring-shaped brazing material 13, as shown in FIG. 5, and the cap 12 is soldered.

Next, the thin tube 11 provided in the cap 12 is connected to a vacuum pump (not shown), and after deaerating the air inside and reducing the pressure, water, alcohol, ammonia, etc. A heat pipe is created by injecting liquid 4.

Note that this sealing method is not limited to this, but may include a method of injecting the working fluid 4 into the metal tube 1 in advance, degassing it with a vacuum pump, and then sealing it by spot welding or ultrasonic welding.
Alternatively, a method of heating the injected working fluid 4 and sealing it off in a boiling state or sealing it with a sealing plug may be used.

In the above method, one end of the metal tube 1 is formed by drawing, but a case where drawing is applied to both ends of the metal tube will be described below.

As shown in FIG. 6, after forming grooves 14 for capillary action on the inner surface of the metal tube 1, the metal tube 1 is attached to a drawing machine as shown in FIG. 2, and then as shown in FIG. A rod-shaped brazing material 8 is inserted between two ends of a metal tube 1 and drawn to form a hemispherical shape.

Next, after heating and sealing this brazing material 8, this metal tube 1
The metal tube 1 is reversed and attached to a drawing machine, and the open end of the metal tube 1 is drawn with a spatula in an air-core state to form a hemispherical shape, and a narrow opening 15 is formed in the center thereof.

After that, the hydraulic fluid 4 is injected into the inside through the narrow opening 15,
Next, this is heated to a boiling state, and the narrow opening 15 is sealed with a sealing plug 5 to form a heat pipe.

The heat pipe thus obtained does not require a cap, and its sealing portion is extremely small, so it is easy to manufacture and has excellent pressure resistance.

Moreover, since this heat pipe has grooves 14 extending to the ends of the pipe to eliminate capillary action, the working fluid 4 can be sufficiently sucked up and the amount of heat transported can be increased.

Next, examples of the present invention will be described.

Example 1 Pre-degreased and pickled outer diameter 16mm, wall thickness 0.711! +
11 After attaching a copper pipe with a length of 400 mm to the spatula drawing machine as shown in Fig. 2, insert and support a silver solder rod with an outer diameter of 3 mm supported by a solder metal support into the tip of the pipe. In this state, a spatula drawing process is performed to form a hemispherical shape, and a silver solder rod is held in the center of the semispherical shape.

Next, this silver solder rod is cut, heated and soldered, and then a 100-mesh phosphor bronze wire mesh wound in three layers is inserted from the open end.

Next, as shown in Fig. 5, a cap with a protruding thin tube is soldered to the open end, and 15 minutes of Dowsome A is passed through the thin tube.
cc was injected, the thin tube was sealed off while heating under reduced pressure, and this portion was soldered to form a heat pipe.

The heat pipe manufactured by this method has a manufacturing time of about 30 inches shorter than the conventional double-end cap type heat pipe shown in Fig.
cI? L and 120k of both end cap type heat pipe
It had excellent pressure resistance compared to g/d.

Example 2: Outer diameter 25.4ixm, wall thickness 1.5mm, with grooves pre-processed on the inner surface.
A deoxidizing steel pipe with a weight of 2 mg and a length of 20001 m is prepared.

The grooves had a rectangular cross section with a width of 0.15 mg and a depth of 0.2 mm, and were formed at a pitch of 0.4 mm.

Next, after attaching this deoxidized steel pipe to a spatula drawing machine, a silver solder rod with an outer diameter of 5 mm supported by a brazing metal support was inserted and supported at the tip, and spatula drawing was performed in this state. It is shaped like a hemisphere, and a silver solder rod is held in the center of it.

Next, after cutting this silver solder rod, it was heated with a burner and soldered.

Next, this deoxidized steel pipe is reversed and attached to a spatula drawing machine, and then drawn in an air-core state to form a hemispherical shape, and a narrow opening is formed in the center.

Next, 200 cc of water was injected through the narrow opening, heated, and in a boiling state, the narrow opening was sealed with a sealing plug to produce a heat pipe as shown in FIG.

The heat pipe manufactured in this manner was able to reduce the manufacturing cost by about 40% compared to the conventional double-end cap type heat pipe shown in FIG.

In addition, it has excellent pressure resistance with an internal pressure failure of 180 kg/d;
showed that.

In addition, in order to measure the amount of heat transport, one end was
Heat intensively over a range of 1, and 100i+ at the other end.
M was water-cooled, and the rise in water temperature was investigated while insulating the center with asbestos cloth.

As a result, the amount of heat transported at a heating temperature of 130° C. was increased by about 15 times compared to the conventional double-ended cap type heat pipe.

Furthermore, when the end was cut and observed to confirm the inner surface condition of the heat pipe, it was found that continuous high-density grooves were formed on the inner surface of the hemispherical end.

In the present invention, the shape of the tube end formed by drawing is not limited to a hemispherical shape, but may be a conical shape.

Furthermore, in the above embodiment, a wick or groove was provided on the inner surface of the metal tube to promote the return of the working fluid by capillary action. It is not always necessary when manufacturing pipes.

As explained above, according to the method for manufacturing a heat pipe according to the present invention, by drawing the end of the tube with rod-shaped brazing material inserted, the cap portion can be integrally formed and the brazing material can be held between the ends. It is extremely easy to work with.

In addition, since there are few solder joints at the end of the tube, there are fewer thermal effects and poor solder joints due to heating during soldering, and the tube has excellent pressure resistance.

Furthermore, the heat pipe obtained by the method of the present invention has remarkable effects such as the ability to easily attach fins to the end of the tube, which has been enlarged by fitting a cap, without finishing, unlike the conventional double-end cap type heat pipe. It has the following.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a double-end cap type heat pipe manufactured by the conventional method, FIGS. 2 to 5 are cross-sectional views sequentially showing the manufacturing process of a heat pipe with one end drawn by the method of the present invention, and FIG. FIG. 2 is a cross-sectional view of a heat pipe manufactured by drawing both ends by the method of the present invention. DESCRIPTION OF SYMBOLS 1... Metal tube, 2, 2'... Cap, 3... Insertion hole, 4... Hydraulic fluid, 5... Seal plug, 6...
...Rotating shaft, 7... Support, 8... Brazing material, 9...
・Spatula, 10...wick, 11...tubule, 12・
... Cap, 13 ... Brazing material, 14 ... Groove, 1
5...Narrow mouth.

Claims (1)

[Claims] 1. With a bar-shaped brazing material inserted into one end of the metal tube, the end of the tube is drawn and the brazing material is clamped, then this part is heated and brazed, and then the other opened metal tubes are A method for manufacturing a heat pipe, characterized by injecting a working fluid into the interior from the end and sealing the open end under reduced pressure.