JPH09295037A - Method and device for production of inner face grooved metal tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce an inner face plurally grooved metal tube having uniform heat transfer and high quality by forming plural uniform grooves on the inner face of a metal tube. SOLUTION: A metal tube 1, in which a plug unit 17 is inserted, is moved from left of figure to right (arrow mark D direction), the metal tube 1 is applied at the position of grooved plug 4 with form rolling pressure by plural balls 10 rotating in planetary state, a primary groove 13 and fin 14 are continuously formed on the inner face of metal tube 1 to form a primary grooved metal tube 12. Further, by moving the primary grooved metal tube 12 in the downstream direction, the fin 14 of primary grooved metal tube 12 are cut off by a protrusion 7 of a protruded plug 6 equipped with self aligning function, a secondary groove 15 is continuously formed on the inner face of primary grooved metal tube 1, an inner face grooved metal tube 16 having the grooves 13, 15 on inner face is produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for manufacturing a metal tube having an inner surface groove, and more particularly to an inner surface grooved material for forming multiple grooves on the inner surface of the metal tube by means of a rolling pressure applying means and a plurality of groove processing means. The present invention relates to a method of manufacturing a metal tube and an apparatus thereof.

[0002]

2. Description of the Related Art Conventionally, copper or copper alloy bare tubes have been used as heat transfer tubes for heat exchangers. Recently, as the heat transfer tube for such a heat exchanger, an inner grooved metal tube having high heat transfer performance even for a fluid such as CFCs that changes in phase has been widely used.

Such a heat transfer tube for a heat exchanger is a metal tube with an inner surface groove having fine spiral grooves on the inner surface for improving the heat transfer performance, and recently, for improving the heat transfer performance, an inner surface groove is formed. It is a double metal tube with inner groove.

FIG. 3 shows an inner surface double grooved metal pipe manufacturing apparatus which is one form of a conventional inner surface grooved metal pipe manufacturing apparatus. This manufacturing apparatus is configured to rotate the outer peripheral surface of the metal tube 1 in a planetary shape in a direction orthogonal to the tube axis and apply a rolling pressure to the metal tube 1 in the radial direction on the outer peripheral surface to contract the metal tube 1. Sphere 10 and metal tube 1
The drawing die 9 for locking the floating plug 2 inside is connected to the floating plug 2 by the connecting rod 3,
The primary groove 13 and the fins 1 are provided inside the metal tube 1 which is rotatably inserted into the metal tube 1 and contracted by the sphere 10.
A grooved plug 4 having a groove 5 forming a groove 4 and a metal rod bearing or a thrust bearing 8 having a small friction are installed on the connecting rod 3 at the rear of the grooved plug 4 so as to be connected. And a plug 6 having a protrusion 7 for processing the secondary groove 15 inside the primary grooved metal tube 12 by pulling out the primary grooved metal tube 12 and a plug 6 with an inner surface. It has a finishing die 11 for finishing a metal tube 16 having a double groove formed into an inner surface double grooved metal tube 18 having a predetermined outer diameter.

The plug 6 with the projection and the metal tube 1 with the primary groove
FIG. 4 shows a cross-sectional view of the contact position 2 (position A-A).

Since the protruding plug 6 is freely rotatable inside the primary grooved metal tube 12, the connecting rod 3 and the protruding plug 6 are provided.
It is attached so that there is a gap between it and the center hole. That is, the hole diameter D1 of the projection plug 6, the outer diameter D2 of the connecting rod 3, and the gap d have a relationship of D1-D2 = d.

That is, as described above, the inner double-grooved metal tube having high heat transfer performance is manufactured by the grooved plug 4 and the protruding plug 6 which is freely rotatable inside the metal tube.

[0008]

However, according to the conventional apparatus for manufacturing the inner grooved metal pipe, the central axis of the projection plug 6 and the central axis of the primary grooved metal tube 12 do not always coincide with each other. The eccentricity will occur in the plug 6 with the protrusion. Due to the effect of the eccentricity of the plug with protrusions 6, there is a circumferential difference in the amount of the fins 14 formed on the inner wall surface of the metal tube 12 with primary groove that is crushed or scraped by the protrusions 7 of the plug with protrusions 6. Will occur (see circles B and C in FIG. 4). Due to this difference, the secondary groove 15 formed by the protruding plug 6 becomes non-uniform in the circumferential direction in the metal tube, and the heat conductivity of the manufactured inner surface double grooved metal tube 18 becomes non-uniform and the quality is high. It had the drawback of falling.

Therefore, an object of the present invention is to manufacture a metal tube with inner groove having a high quality with uniform heat conductivity by forming a plurality of grooves on the inner surface of the metal tube. A method and an apparatus therefor.

[0010]

In order to achieve the above-mentioned object, the present invention provides a method for producing an inner grooved metal tube having a groove on the inner wall surface, wherein a first groove is formed on the inner wall surface of the metal tube. A primary groove is formed by a processing plug, and a second groove processing plug that is automatically centered so that its central axis coincides with the central axis of the metal tube is arranged in the subsequent stage of the formation position of the primary groove. Then, a method for producing a metal tube with an inner surface groove is provided, in which a second groove having a uniform shape is formed on the inner wall surface of the metal tube in which the primary groove is formed by the second groove processing plug. To do.

To achieve the above object, a rolling pressure applying means for applying a rolling pressure to the metal pipe on the outer periphery of the metal pipe and an inner wall surface of the metal pipe at a position where the rolling pressure is applied are in contact with each other. And a first groove processing means for forming a primary groove on the inner wall surface, and an inner wall surface of a metal pipe connected to a subsequent stage of the first groove processing means and having a self-aligning function and having a primary groove formed therein. And a second groove processing means for forming a secondary groove on the inner surface of the metal tube.

That is, in the apparatus for producing a metal tube with an inner surface groove of the present invention, the second groove processing means is provided with a self-aligning function to make the shape of the groove in the metal tube uniform and to provide uniform heat transfer. It is possible to manufacture a high quality inner multi-grooved metal tube.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The method and apparatus for manufacturing an inner grooved metal tube of the present invention will be described in detail below.

FIG. 1 shows an apparatus for manufacturing an inner double grooved metal tube which is an embodiment of the present invention. This device has multiple balls 1
0, a grooved plug 4 having a groove 5 and a grooved plug 6 having a protruding portion 7, a floating plug 2, a connecting rod 3, a drawing die 9, and a finishing die 11. There is.

The floating plug 2 is locked inside the metal tube 1 at the position of the drawing die 9 by passing the metal tube 1 through the drawing die 9.

Further, the plurality of balls 10 of the groove machining device are formed by rotating the outer peripheral surface of the metal tube 1 in a planetary shape in a direction orthogonal to the tube axis of the metal tube 1 and rolling the outer peripheral surface of the metal tube 1 in the radial direction. Pressure is applied to contract the tube.

The grooved plug 4 having a plurality of fine grooves 5 formed on its outer periphery is rotatably attached to the floating plug 2 via a connecting rod 3.

Further, the projection plug 6 having the projection 7 formed on the outer periphery is connected to the connecting rod 3 by installing the thrust bearing 8 having a small friction, and is connected to the rear side (downstream direction) of the grooved plug 4.
Attached to.

The floating plug 2, the connecting rod 3, the thrust bearing 8, the grooved plug 4, and the protruding plug 6
The plug unit 17 is configured by the above. In the plug unit 17, the grooved plug 4 can be held at a predetermined position (the inside of the metal tube 1 where the ball 10 is installed) by the floating plug 2 engaging with the drawing die 9. Similarly, the projection plug 6 can be held at a predetermined position behind the grooved plug 4.

Therefore, the plug unit 17 is provided in the metal tube 1.
By moving the metal tube 1 from the left to the right in FIG. 1 (in the direction of the arrow D) with the inserted, the metal tube 1 is applied with the rolling pressure by the plurality of balls 10 at the position of the grooved plug 4. Is pressed against the grooved plug 4 to continuously form the primary groove 13 and the fin 14 on the inner surface of the metal tube 1, and
2 is formed.

Next, by moving the primary grooved metal tube 12 further downstream, the primary grooved metal tube 12 intermittently scrapes the fins 14 by the projections 7 of the plugs 6 with projections. The secondary groove 15 is continuously formed on the inner surface of the grooved metal tube 12, and the inner double grooved metal tube 16 having the groove 13 and the groove 15 is formed on the inner surface.

Further, the metal tube 16 with the inner surface groove is used to finish the die 1.
By passing it through 1, the inner surface double grooved metal tube 18 having a desired diameter is formed.

The plug 6 with the projection and the metal tube 1 with the primary groove
A cross-sectional view of the contact position 2 (position AA) is shown in FIG.

Since the protruding plug 6 is free to rotate inside the primary grooved metal tube 12, the connecting rod 3 and the protruding plug 6 are provided.
It is attached so that there is a large gap between it and the hole. That is, the hole diameter D1 of the projection plug 6, the outer diameter D2 of the connecting rod 3, and the gap d1 have a relationship of D1-D2 = d1. The clearance d1 is equal to the eccentricity d of the plug with protrusion 6.
It is twice or more than 2 (d1 ≧ 2 × d2).

Therefore, the eccentricity d of the projection plug 6 is
By providing a gap d1 that is at least twice as large as 2, the center of the protruding plug 6 and the metal tube 1 can be installed when the plug unit 17 is installed.
Even if there is a deviation in the center of the plug (even if the plug with projection 6 is eccentric), the plug with projection 6 can move in the radial direction. Metal tube 1
The two fins 14 are evenly hit (see circles B and C in FIG. 2).

That is, by increasing the hole diameter of the protruding plug 6 through which the connecting rod 3 is inserted, the protruding plug 6 has a centering function of automatically adjusting its own central axis. Since a plurality of uniform grooves are formed on the inner surface of the metal tube, it is possible to manufacture a high-quality inner surface multi-grooved metal tube having uniform heat conductivity.

[0027]

As described above, according to the method and apparatus for manufacturing a metal tube with an inner surface groove of the present invention, a plurality of uniform grooves can be formed on the inner surface of the metal tube, and the inner surface having uniform heat transfer and high quality. It has become possible to manufacture metal tubes with multiple grooves.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of an apparatus for manufacturing a metal tube with an inner groove according to the present invention.

FIG. 2 is a sectional view of a contact portion between a plug with protrusions and a metal tube according to the present invention.

FIG. 3 is a schematic view showing an embodiment of a conventional apparatus for manufacturing a metal tube with an inner groove.

FIG. 4 is a cross-sectional view of a contact portion between a conventional plug with a protrusion and a metal tube.

[Explanation of symbols]

 1 Metal Pipe 2 Floating Plug 3 Connecting Rod 4 Groove Plug 5 Groove 6 Groove Plug 7 Protrusion 8 Thrust Bearing 9 Drawing Die 10 Ball 11 Finishing Die 12 Metal Pipe with Primary Groove 13 Primary Groove 14 Fin 15 Secondary Groove 16 Inner Double Grooved Metal Pipe 17 Plug Unit 18 Inner Double Grooved Metal Pipe

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display area F28F 1/40 F28F 1/40 D

Claims (6)

[Claims] 1. A method of manufacturing an inner grooved metal tube having a groove on an inner wall surface, wherein a primary groove is formed on the inner wall surface of the metal tube by a first grooved plug, and a primary groove is formed at a position where the primary groove is formed. In the latter stage, the second axis is automatically aligned so that the central axis matches the central axis of the metal tube.
The groove processing plug is arranged, and the second wall is formed on the inner wall surface of the metal pipe in which the primary groove is formed.
A method for producing a metal tube with an inner surface groove, characterized in that a secondary groove having a uniform shape is formed by the groove processing plug. 2. A method of manufacturing an inner grooved metal tube having a groove on the inner wall surface, wherein a primary groove is formed on the inner wall surface of the metal tube by a first grooved plug, and a primary groove is formed at a position where the primary groove is formed. In the latter stage, the second axis is automatically aligned so that the central axis matches the central axis of the metal tube.
The groove processing plug is arranged, and the second wall is formed on the inner wall surface of the metal pipe in which the primary groove is formed.
Secondary groove having a uniform shape is formed by the groove processing plug, and the inner wall surface of the metal pipe is processed by one or more processing plugs at the subsequent stage of the secondary groove forming position. Manufacturing method of metal tube. 3. The method for producing a metal tube with an inner surface groove according to claim 2, wherein the processing plug automatically aligns its center axis with the center axis of the metal tube. . 4. A manufacturing apparatus of an inner grooved metal pipe having a groove on an inner wall surface, wherein a rolling pressure applying means for applying a rolling pressure to the metal pipe on the outer periphery of the metal pipe, and the rolling of the metal pipe. A first groove processing means for contacting an inner wall surface at a position where a pressure is applied to form a primary groove on the inner wall surface, and a central axis of the metal pipe connected to a subsequent stage of the first groove processing means. And an inner surface having a self-aligning function of aligning its own axis, and a second groove processing means for forming a secondary groove on the inner wall surface of the metal tube in which the primary groove is formed. Manufacturing equipment for grooved metal pipes. 5. An apparatus for producing a metal tube with an inner surface groove having a groove on an inner wall surface, wherein a rolling pressure applying means for applying a rolling pressure to the metal tube on the outer periphery of the metal tube, and the rolling of the metal tube. A first groove processing means for contacting an inner wall surface at a position where a pressure is applied to form a primary groove on the inner wall surface, and a central axis of the metal pipe connected to a subsequent stage of the first groove processing means. And a second groove processing means for forming a secondary groove on the inner wall surface of the metal tube in which the primary groove is formed, which has an automatic centering function of aligning the self-axis with the second groove processing means. An inner surface grooved metal pipe manufacturing apparatus further comprising one or more metal pipe inner surface processing means which are connected to the subsequent stage and further process the inner wall surface of the metal tube having a double groove formed therein. 6. The apparatus for manufacturing a metal tube with an inner surface groove according to claim 5, wherein the inner surface processing means for the metal tube has the self-centering function.