JPS595048B2 - Manufacturing method of raw tube for unidirectional heat pipe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a raw tube for a unidirectional heat pipe.

Conventionally, inner finned tubes having fins on the inner wall surface parallel to the axial direction and whose number and height are reduced in one direction have been widely used as raw tubes for heat pipes.

The production of the above-mentioned inner finned tube generally involves rolling, drawing,
Processing methods such as cutting are used.

However, each of the above-mentioned processing methods not only requires a large number of man-hours, but also requires a cutting process or a tube welding process to produce fins with different shapes in the axial direction, making the process even more complicated. had.

The present invention has been made in view of the above-mentioned drawbacks of the conventional art, and it does not require the complicated processes of the conventional art, has a uniform fin shape, is seamless, and is capable of statically forming an inner finned tube with different fin shapes in the axial direction. It is an object of the present invention to provide a method for manufacturing a raw tube for a unidirectional heat pipe using hydraulic extrusion.

Next, the present invention will be explained according to the drawings which are examples.

1 to 7 show the main parts of a manufacturing device for a unidirectional heat pipe base tube applied to the method of the present invention, in which 1 is a billet container, and a cylinder 2 is provided in the solid axial direction. A die 3 is removably fitted into the tip of the cylinder 2, and is stably held at a proper position by a support fitting 4.

A pressure generator 5 is provided at the rear of the billet container 1 on the same axis as the billet container 1, a cylinder 6 is provided in the direction of the solid axis of the pressure generator 5, and the rear end of the cylinder 6 is provided with a cylinder 6. A stem 7 is slidably inserted.

An intermediate connecting portion 8 is provided between the billet container 1 and the pressure generator 5, and a liquid supply hole 9 is provided in the direction of the solid axis.

Insert parts 10.11 are provided at the front and rear ends of the intermediate connecting part 8, the insertion part 10 at the front end is connected to the rear end of the cylinder 2 of the billet container 1, and the insertion part 11 at the rear end is connected to the pressure generator 5. are slidably fitted into the front end portions of the cylinders 6, respectively.

A mandrel holder 12 having a liquid supply hole 13 is screwed onto the tip of the front end insertion portion 10 of the intermediate connecting portion 8, and the mandrel holder 12 has a large diameter portion 15 at the rear end, and a product is inserted into the tip. A mandrel 14 having a sizing portion 16 that determines the inner diameter is mounted via a spring 17 so as to be movable in the axial direction.

Behind the tip sizing portion 16 of the mandrel 14, as shown in FIG. 3, there is a tapered initial seal portion 18.
A molded portion 19 is provided at the tip thereof, and a tapered portion 20 and a small diameter portion 21 are provided at the tip of the molded portion 19.

Similarly, the effect of the present invention is not affected even if this small diameter portion 21 is not provided separately.

The molded part 19 is molded so that the outer diameter of the rear end is slightly larger than that of the front end, or both have the same dimensions, and the outer surface of the molded part 19 has a long groove 22 and a short groove 23, as shown in FIG.
are arranged rearward from the end surface of the tapered portion 20, parallel to the axis of the mandrel 14, and alternately at regular intervals.

As shown in FIGS. 5, 6, and 7, the depth of the valley grooves 22 and 23 becomes gradually shallower from the tip to the rear end of the molded part 19, and becomes longer from the middle to the rear. Only the grooves 22 are provided, the number of grooves is also halved, and the distance from the axis of the mandrel 14 to the bottom of the valley grooves 22, 23 is smaller at the tip than at the rear or middle of the forming section 19.

Note that 24 is a pressure-resistant seal, and 25 is a billet.

Next, the operation of the apparatus for manufacturing a unidirectional heat pipe base tube having the above configuration will be explained.

First, as shown on the left side from the center of FIG. 1, the support fitting 4 is removed from the tip of the billet container 1, the die 3 is pulled out forward, and the
The front insertion part 10 of the intermediate connecting part 8, which has the large diameter part 15 of the mandrel 14 attached to the tip of the mandrel holder 12 via the spring 17, is inserted into the cylinder 2 together with the mandrel 14, and the stepped part 10a of the insertion part 10 is inserted. While providing a predetermined gap 26 between the rear end surface of the cylinder 2 and the rear end surface of the cylinder 2, the rear insertion part 11 of the intermediate connecting part 8 is fitted into the front end of the cylinder 6 of the pressure generator 5, and the stepped part of the insertion part 11 is fitted into the front end of the cylinder 6 of the pressure generator 5. 11a and the front end surface of the pressure generator 5 are brought into contact.

Next, as shown on the right side from the center of FIG. 1, a hollow billet 25 whose tip portion 25a has been formed into a conical outer surface and inner surface in advance is inserted into the cylinder 2 of the billet container 1 from its rear end. , the tip 25a of the billet 25
The die 3 is brought into contact with the outer surface, and the die 3 is fitted into a predetermined operating position of the cylinder 2 by the support metal fitting 4 against the repulsive force of the spring 1T.

At this time, the mandrel 14 is retracted from the forward position and is not fixed in the axial direction, and the mandrel 14 is not fixed in the axial direction.
The initial seal portion 18 of No. 4 is in surface contact with the tip portion 25 & inner surface of the billet 25.

As described above, since the mandrel 14 and the die 3 are in contact with the inner and outer surfaces of the tip 25a of the billet 25, initial sealing is reliably performed.

Then, a suitable pressure medium 27 is introduced into the cylinder 6 of the pressure generator 5.

Now, when the stem 7 is moved forward, the pressure medium 27 in the cylinder 6 of the pressure generator 5 is pressurized and flows from the cylinder 6 into the mandrel holder 12 through the liquid supply hole 9 provided in the intermediate connection part 8. The large diameter portion 15 at the rear end of the mandrel 14 is pushed forward by the pressure, and the tip sizing portion 16 of the mandrel 14 is moved forward as shown on the left side from the center of FIG.
The inner surface of the tip end 25a of the billet 25 is deformed to make the first setting position of the forming part 19 correspond to the die 3.

On the other hand, the pressurized pressure medium 27 is transferred to the mandrel holder 12.
It flows into the cylinder 2 of the billet container 1 through the liquid supply hole 13 provided in the billet container 1 .

When the pressure medium 27 is pressurized to a predetermined extrusion pressure by the continuous advancement of the stem 7, the billet 25 is extruded through the space between the die 3 and the tip forming part 19 of the mandrel 14 due to the pressure of the pressure medium 27. As shown in Figure 8,
Pipe 28 (product) with many fins 29 on the inner wall surface
is formed into.

When the length of the extruded pipe 28 reaches a predetermined length, the intermediate connecting portion 8 is advanced by the gap 26 by an appropriate moving means (not shown) without stopping the forward movement of the stem 7. The front step portion 10a of the billet container 1 is brought into contact with the rear end surface of the billet container 1.

At this time, the length of the pipe 28 is detected by directly detecting the length of the pipe 28 or by detecting the displacement of the stem 7 using an appropriate detection means (not shown).

As the intermediate connecting portion 8 moves forward, the mandrel 14
moves forward, and the second set position of the molding section 19 is fixed at a position corresponding to the die 3, as described above, and the second set position of the molding section 19 and the die 3 cause the molding section 19 to move forward, as shown in FIG.
A pipe 28 having fins 29 whose number is reduced by half and whose height is lower than that of the product extruded at the first setting position is continuously formed on the inner wall surface.

When the mandrel 14 moves forward, the mandrel 14 is held movably in the axial direction by the mandrel holder 12 via the suffling 17 at the tip of the intermediate connecting portion 8, so that no compressive force in the axial direction is applied to the mandrel 14G. Therefore, problems such as buckling do not occur.

When the length of the extruded pipe 28 reaches a predetermined length, the forward movement of the stem 7 is stopped, and then the pressure medium 27 is depressurized by retracting the stem 7, and the extrusion molding is completed.

Next, the inventor conducted an experiment using the above device, and the results were as follows.

Experimental example 1 From a steel pipe with an outer diameter of 38φ and an inner diameter of 22φ, an outer diameter of 20 mm was produced at room temperature.
φ, innermost diameter 16.4φ, fin height 0.6 mm, fin middle 0.5 mm, and 54 fins. Height Q, 3 mm.

When a tube with inner fins having a cross-sectional shape of 0.5 mm in the fin and 27 fins was extruded for 0.5 m, the inner tube with the above-mentioned sound cross-sectional shapes was extruded at an extrusion pressure of 11,200 to 12,000 Y/-. It was possible to extrude a finned tube (first
(See figure 0).

Experimental Example 2 From the same steel pipe as in Experimental Example 1 above, a cross section with an outer diameter of 20φ, innermost diameter of 16.4φ, fin height of 0.6mm, fin middle of 0.5 mrn, and number of fins of 54 was prepared at room temperature. After extruding 2rrL of the inner finned tube having the same shape, the pressure medium 27 is once lowered, the 20φ60° die is replaced with a 21φ90° die, a lubricant (MoS2) is applied to the die surface, and the mandrel is moved forward by 465 mm. Pressure medium 27
was pressurized to extrude 0.5 m of an inner finned tube having an outer diameter of 21.5 φ, an innermost diameter of 16.4 φ, a fin height of 0.3 m - 0.5 mm in the fin, and a cross-sectional shape with 27 fins.

In this case, the extrusion pressure of the former is 11,200 kg/chi
The latter extrusion pressure has a starting pressure of 13,000 kg/
aa, the steady pressure was 11.700 kg/cmt, and it was possible to extrude an inner finned tube having sound straight extensibility, fin shape, etc. (see Fig. 11).

Experimental Example 3 After lowering the pressure of the pressure medium 27 in the same manner as in Experimental Example 2 above, the mandrel was advanced by 4.5 mm in the same manner as above without replacing the die, and the pressure medium 27 was increased in pressure again to extrude. Pressure is 14,000kg/c! 1, the product suddenly flew out, the product's appearance was bent and damaged, and the fin shape was broken and discontinuous, making it impossible to obtain a healthy inner finned tube (see Figure 12).

As shown in Experimental Example 1 above, it was confirmed that by using this apparatus, it was possible to easily form a heat pipe base tube with directionality from a simple tube body by one step of pressure extrusion. At the tip of the molding section 19 (first setting position), the depths of the two types of grooves 22 and 23 are almost the same, and at the center of the molding section 19 (second setting position), only the long groove 22 is formed. , the number of grooves is half that of the former, and the intermediate part between the tip and the center corresponds to the changing part of the fin shape of the heat pipe, and in order to reduce the pressure loss of the working fluid of the heat pipe, the intermediate part The short groove 23 disappears smoothly.

13 to 15 show a second embodiment, and 30 is a high-pressure container, which is an integral structure of the billet container 1 and pressure generator 5 in the first embodiment.

A stem 31 is slidably fitted into the rear end of the high-pressure container 30, and a plunger 32 passes through and is slidably fitted into the center of the stem 31. They are designed to move separately.

A tightening fitting 34.3 is attached to the protruding tip of the plunger 32.
A mandrel holder 33 consisting of a mandrel 14 is screwed onto the mandrel holder 33, and a large diameter portion 15 of the mandrel 14 is attached to the mandrel holder 33 via a spring 17 so as to be movable in the axial direction.

In the apparatus ζ having the above configuration, the plunger 32 is used to control the tip of the forming part 19 of the mandrel 14 (first setting position).
as shown on the left side from the center of FIG.
8, the stem 31 is further continuously advanced, and the plunger 32 is advanced by a predetermined distance to move the center part (second setting position) of the molding part 19,
As shown on the right side from the center of FIG. 13, it is opposed to the dice 3.

Note that the same parts as in FIGS. 1 and 2 are denoted by the same reference numerals, and explanations thereof will be omitted.

In the second embodiment, the mandrel holder 33 consisting of the fastening fittings 34 and 35 is used to attach the mandrel 14 to the tip of the plunger 32, but the invention is not limited to this, and as shown in FIG. As shown, plunger 32
The mounting bracket 36 may be screwed onto the tip of the mounting bracket 36, the large diameter portion 15 of the mandrel 14 may be inserted into the recessed end thereof via the spring 17, and a retaining bracket 37 may be screwed onto the tip of the mounting bracket 36. Further, as shown in FIG. 15, a recess 38 is provided at the tip of the plunger 32, and after the large diameter portion 15 of the mandrel 14 is inserted into the recess 38, a retaining fitting 37 is screwed onto the tip of the recess 38. Of course, it is also possible to do so.

Further, in the first embodiment, the long grooves 22 and the short grooves 23 are parallel to the axis and are alternately arranged in the tip forming part 19 of the mandrel 14, but the present invention is not limited to this. As shown in FIG. 16, between the long grooves 22, 22
A short groove 23 is provided, and the cross-sectional shape of the molded portion 19 is shown in FIG. 17 at the tip, FIG. 19 at the center, and FIG. 18 at the intermediate portion between the tip and the center. Of course, it may be formed as follows.

As is clear from the above description, the present invention has a large diameter section at the rear end of a movably provided intermediate connecting section or plunger with a mandrel holder, and a sizing section at the tip that determines the inner diameter of the product. The large diameter part of the rear end of the mandrel is grasped and supported so as to be movable in the axial direction via a spring, and the mandrel is advanced by advancing the intermediate connecting part or the plunger during extrusion. Since no compressive stress in the axial direction is applied to the mandrel, extrusion can be performed continuously without buckling the mandrel.

The sizing section at the tip of the mandrel is provided with a large number of grooves parallel to the axial direction whose number and depth decrease toward the rear from the tip, and the position of the sizing section is adjusted to the tip by advancing the mandrel during extrusion as described above. Because the fins are displaced rearward from R, they do not require a large number of man-hours and welding processes as in conventional fins, and the height and number of fins at the rear end are reduced compared to the front end with a single pressurization. It is possible to continuously extrude raw tubes for unidirectional heat pipes having different shapes.

The initial seal at the tip of the mandrel is brought into contact with the inside of the billet's tip by the repulsive force of the spring, and the outer surface of the billet's tip is brought into contact with the die, making it possible to perform the initial seal during hydrostatic extrusion without using dead metal. effective.

[Brief explanation of the drawing]

1 to 7 are drawings showing a first embodiment/example of the apparatus to which the method according to the present invention is applied, FIGS. 1 and 2 are cross-sectional views, and FIG. 3 is the tip of the mandrel in FIG. 1. An enlarged side view of the sizing part, Fig. 4 is a partially enlarged side view of Fig. 3, Fig. 5 is a line ■-■ of Fig. 4, and Fig. 6 is a line Vl-Vl of Fig. 4.
Figure 7 is a cross-sectional view taken along the line ■-■ in Figure 4, Figures 8 and 9 are cross-sectional views of the extruded tube with inner fins, and Figures 10 to 12 are experiments conducted by the inventor. Drawings showing the relationship between pressure and time in extrusion processing, Figs. 13 to 15 are drawings showing a second embodiment of the apparatus to which the method according to the present invention is applied, Fig. 13 is a cross-sectional view, and Fig. 14 , FIG. 15 is a sectional view showing a modification of the mandrel holder for attaching the mandrel to the tip of the plunger in FIG. 13, FIG. 16 is a side view showing a modification of FIG. X■−X■
18 is a sectional view taken along line X--X in FIG. 16, and FIG. 19 is a sectional view taken along line X--X in FIG. 16. 1... Billet container, 2, 6... Cylinder, 3... Dice, 5... Pressure generator, T, 31... Stem, 8... Intermediate connection portion, 12, 33... Mandrel holder, 1
4... Mandrel, 15... Large diameter part,
16...Sizing part, 17...Spring, 18...Initial seal part, 19...
...Molding part, 22...Long groove, 23...
・Short groove, 25... Billet, 26...
・Gap, 27...Pressure medium, 28...
Pipe, 29...Fin, 30...High pressure vessel, 32...Plunger.

Claims (1)

[Claims] 1. A sizing part having a large diameter part at the rear end, and having a large number of grooves parallel to the axial direction that determine the inner diameter of the product at the tip and whose number and depth decrease toward the rear from the tip;
A mandrel having an initial sealing part consisting of a tapered part at the rear is held by a mandrel holder at the tip of a plunger for moving the mandrel, which is provided so as to be movable in the axial direction. A billet supported so as to be movable in the axial direction relative to the moving plunger and having an inner surface of the tip corresponding to the initial seal portion is positioned in the cylinder and extruded by hydrostatic pressure, and the mandrel moving plunger is advanced during extrusion. By moving the mandrel forward, the position of the sizing part is shifted backward from the tip, and the inner finned tubular body is hydrostatically extruded at the tip (compared to the rear end, where the height and number of fins are reduced). A method for manufacturing a raw tube for a unidirectional heat pipe, characterized by: