JPH09295030A - Manufacture of tube having grooved inside surface and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a manufacturing method and device of a tube having multiple groove on the inside surface for freely changing the shape of groove without increasing drawing force while impressing rolling pressure. SOLUTION: By moving a metallic tube in the direction of the arrow A in the state where a plug unit 28 is inserted into the metallic tube 1, the metallic tube is reduced with plural balls 8 supported with back-up rolls 20 and pressed against the grooved plug in the position of a grooved plug 4, primary grooves 11 and fins 15 are formed on the inside surface of the metallic tube and a primary grooved tube 12 is formed. By moving the primary grooved tube 12 in the direction of the arrow A, the tube is impressed by rolling pressure with plural balls 9 supported back-up rolls 20, pressed against the grooved plug 6. The fin 15 parts of the primary grooved tube 12 are intermittently shaved with the grooves 7 of the grooved plug, the secondary grooves 13 are formed, the secondary grooved tube 14 having the grooves 11 and grooves 13 on the inside surface is formed and, further, the tube 23 having the grooved inside surface which is reduced to a prescribed dimension of the outside diameter with a finishing die 18 is formed.

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 an inner surface grooved tube, and more particularly to an inner surface grooved tube for forming a groove on the inner surface of a metal tube without increasing drawing force while applying rolling pressure. Manufacturing equipment.

[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 tube having high heat transfer performance to a fluid such as CFCs which changes in phase has been widely used.

Such a heat transfer tube for a heat exchanger is an inner grooved tube having fine spiral grooves on the inner surface for improving heat transfer performance, and recently, for improving heat transfer performance, two inner surface grooves are provided. It has a heavy inner grooved tube.

FIG. 4 shows an inner surface double grooved tube manufacturing apparatus which is one form of a conventional inner surface grooved tube manufacturing apparatus. The manufacturing apparatus rotates a plurality of balls 8 and 9 in a direction orthogonal to the tube axis on the outer peripheral surface of the metal tube 1 in a planetary manner, and pushes the metal tube 1 in the outer peripheral surface in a radial direction to generate a rolling pressure. Two rolling pressure applying means 16 and 17 on the same axis for applying and contracting the tube, a locking means 10 for locking the floating plug 2 inside the metal tube 1, and a connecting rod 3 for the floating plug 2. The connected primary grooved plug 4 is rotatably inserted into the metal tube 1 and is contracted by the rolling pressure applying means 16 to form the primary groove 11 inside the metal tube 1. The first groove processing means, and further, the secondary grooved plug 6 connected to the rear side of the primary grooved plug 4 by the connecting rod 3 is inserted into the primary grooved metal pipe 12 in a freely rotatable state, and A metal tube 12 with a primary groove is formed by contracting the rolling pressure applying means 17. It is an apparatus for manufacturing the inner surface double grooved tube by a second groove processing means for processing the 2 Tsugimizo 13 therein.

That is, the rolling tools 16 and 17 which are the rolling pressure applying means of the manufacturing apparatus are arranged in two stages, and the grooves formed at the corresponding positions of the rolling tools 16 and 17 are connected to the floating plug 2. By arranging the grooved plugs 4 and 6 which are means,
Double grooving was continuously performed inside the metal tube 1.
Therefore, by moving the metal tube 1 from the left to the right (direction of arrow A), the metal tube 1 is moved by the primary rolling tool 16 (sphere 8) that rotates like a planet at the position of the primary grooved plug 4. A rolling pressure is applied, the tube is compressed and pressed against the primary grooved plug 4, the primary groove 11 is continuously formed on the inner surface, and then the secondary rolling tool 17 and the secondary groove are formed in the same process. The secondary groove 13 is formed by the attached plug 6, and therefore, the double grooves 11, 13 are continuously formed on the inner surface of the metal tube 1.

In this way, the inner surface double grooved tube having high heat transfer performance is manufactured by the manufacturing apparatus.

[0007]

However, according to the conventional apparatus for manufacturing the inner grooved tube, the rolling tool for rotating the outer peripheral surface of the metal tube 1 and the floating plug 2 in the metal tube 1 are used.
The rolling pressure generated by the rolling tool set (for example, a pair of the rolling tool 16 and the grooved plug 4) including the grooved plugs connected to each other by the connecting rod 3 causes a large tensile force to the metal pipe, However, a large pulling force is required, and the metal pipe is easily broken. Furthermore, in order to manufacture an inner grooved tube with higher heat transfer performance, two or more rolling tool sets are required when the grooves on the inner surface of the metal tube are double or more, and the tensile force for the metal tube is further increased. And the pulling force also increases, and the risk of breaking the metal pipe increases. Further, when the rolling tool set has two stages as shown in FIG. 4, the structure of the apparatus is complicated, and therefore it is difficult and time-consuming to adjust the two rolling tool sets. Furthermore, in order to manufacture an inner grooved tube with higher heat transfer performance,
If the number of grooves on the inner surface of the metal pipe is three or more, it is necessary to improve the equipment, and it is extremely difficult to make initial adjustments and speed changes of three or more rolling tool sets, and the pulling force is increased to increase the metal pipe The risk of breakage increases. In addition, in order to prevent the fracture of the metal pipe, the shapes of the grooves 5 and 7 of the grooved plugs 4 and 6 must be restricted (for example, the grooves 5 and 7 are shallow, the number of the grooves 5 and 7 is reduced, etc.). ), Therefore, the flexibility of the shapes of the grooves 5 and 7 is lacking, and it is difficult to manufacture an inner grooved tube having higher heat transfer performance. Furthermore, as the number of rolling tool sets increases, the friction heat between the metal pipe and the rolling tool due to the rolling pressure also increases, and cooling against such friction heat becomes difficult.

[0008] Therefore, an object of the present invention is to reduce the rolling force to reduce the tensile force against a metal pipe,
An object of the present invention is to provide an apparatus for manufacturing an inner grooved pipe that reduces the pulling force and prevents the metal pipe from breaking.

Another object of the present invention is to provide an apparatus for manufacturing an inner grooved tube, which can easily adjust a plurality of rolling pressure applying means in a short time.

Still another object of the present invention is to provide an inner surface grooved pipe manufacturing apparatus capable of easily forming multiple grooves on the inner surface of a metal tube without modifying the apparatus and changing the shape of the groove freely. Is to provide.

Still another object of the present invention is to provide an apparatus for manufacturing an inner grooved tube which can easily cool the metal tube and the rolling pressure applying means against frictional heat.

[0012]

In order to achieve the above-mentioned object, the present invention groove-rolls a rolling pressure applying means consisting of a plurality of spherical bodies and a plurality of roll-shaped rotating bodies supporting the spherical bodies. Provided is an apparatus for manufacturing an inner grooved pipe, which forms a groove on the inner peripheral surface of a metal pipe by arranging it at the position of the means.

In order to achieve the above object, a plurality of rolling pressure applying means are provided, a plurality of groove processing means in the plurality of rolling pressure applying means rotate independently of each other, and a plurality of rolling operations are performed. Provided is an apparatus for manufacturing an inner grooved tube in which a pressure applying means is supported by one rotating body.

Furthermore, in order to achieve the above object, a rolling pressure is applied to the outer circumference of the metal tube by a plurality of spherical bodies supported by a plurality of roll-shaped rotating bodies, and the rolling pressure is applied to the outer periphery of the metal tube. Provided is a method for manufacturing an inner grooved pipe in which a groove is formed on the inner wall surface of a metal pipe.

That is, the inner grooved pipe manufacturing apparatus of the present invention is
By supporting a plurality of spheres in the rolling pressure applying means with a plurality of roll-shaped rotating bodies, the rolling pressure is reduced, thus reducing the tensile force on the metal pipe, and the pulling force is reduced to prevent the metal pipe from breaking. This is something that can be prevented.

Further, even when there are a plurality of rolling pressure applying means, a plurality of groove processing means in the plurality of rolling pressure applying means can rotate independently of each other, and a plurality of rolling pressure applying means can be used. Is supported by a rotating body of No. 1 so that the rolling pressure applying means and the groove processing means can be easily adjusted in a short time. Further, the grooves on the inner surface of the metal pipe can be easily multiplexed. Also, the shape of the groove can be freely changed.

[0017]

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

FIG. 1 shows an embodiment of the present invention. This apparatus includes first rolling pressure applying means, second rolling pressure applying means, first rolling pressure applying means,
A groove processing device including a groove processing means, a second groove processing means, a spacer 26, a reinforcing ring (rotating body) 24, and a rotary head 27, a floating plug 2, a connecting rod 3, a drawing die 10, and a finishing die. It consists of eighteen.

The floating plug 2 is locked inside the metal tube 1 at the position of the drawing die 10 by passing the metal tube 1 through the drawing die 10.

Further, the plurality of balls 8 which freely rotate in the outer peripheral direction and the drawing direction of the metal tube 1 supported by the plurality of backup rolls 20 which are the first rolling pressure applying means of the groove processing device are the backup rolls. It is pressed by 20 and comes into contact with the outer peripheral surface of the metal tube 1 so that the inscribed circle diameter thereof becomes a predetermined dimension.

Further, the plurality of balls 9 which freely rotate in the outer peripheral direction and the pulling direction of the metal tube 12 supported by the plurality of backup rolls 20 which are the second rolling pressure applying means of the groove processing apparatus are also the same. The backup roll 20 is pressed to come into contact with the outer peripheral surface of the metal tube 12, and the inscribed circle diameter thereof is the same as the predetermined dimension.

Further, each of the backup rolls 20
Are connected to the reinforcing ring 24 and the rotary head 27 by a shaft 25. Here, a thrust bearing 19 for reducing a frictional force is installed between the backup roll 20 and the reinforcing ring.

The sphere 8 and the sphere 9 are the spacer 2
The installation position is determined by 6, and the sphere 8, the sphere 9, and the reinforcing ring 24 are kept from contacting each other by the spacer 26 installed therebetween.

Here, the grooved plug 4, which is the first groove processing means and in which a plurality of fine grooves 5 are formed on the outer periphery, is rotatably attached to the floating plug 2 via the connecting rod 3.

Further, the grooved plug 6 having a plurality of fine grooves 7 formed on the outer periphery, which is the second groove processing means, is the connecting rod 3
It is attached to the rear of the grooved plug 4 via.

Further, a thrust bearing 19 having a small friction, a metal bearing and the like are installed between the grooved plug 4 and the grooved plug 6 so that the grooved plug 4 and the grooved plug 6 rotate independently. It can be mounted as you can.

A plug unit 28 is constituted by the floating plug 2, the connecting rod 3, the grooved plug 4, the grooved plug 6, and the thrust bearing 19. In the plug unit 28, the grooved plug 4 can be held at a predetermined position (the inside of the metal tube 1 at the position where the plurality of balls 8 are installed) by the floating plug 2 engaging with the drawing die 10. Similarly, the grooved plug 6 can be held at a predetermined position behind the grooved plug 4 (inside the metal tube 12 where a plurality of balls 9 are installed). Has become.

Here, FIG. 2 shows a schematic view of an example of a cross section of the plurality of balls 8 and the backup roll 20 installed on the outer peripheral surface of the metal tube 1. As shown in FIG. 2, one backup ball 20 is supported by two adjacent backup rolls 20. Here, the number of the balls 8 and the number of the backup rolls 20 are four, but the number is not limited to four.
Any number is acceptable.

In FIG. 1, the plurality of spheres 8 and 9 are
When the rotating body composed of the rotating head 27 and the reinforcing ring 24 rotates, the rotating body simultaneously rotates via the plurality of backup rolls 20.

Therefore, the plug unit 28 is provided in the metal tube 1.
1 is moved from left to right in FIG. 1 (in the direction of arrow A), the metal tube 1 is contracted by a plurality of balls 8 that freely rotate at the position of the grooved plug 4. It is pressed against the grooved plug 4, and the primary groove 11 and the fins 15 are continuously formed on the inner surface of the metal tube 1 to form the primary grooved tube 12.

The outer diameter of the projection of the groove 7 of the grooved plug 6 is larger than the inner diameter of the fin 15 (projection) in the primary grooved pipe 12 and inside the primary grooved pipe 12. Primary groove 1
It is smaller than the diameter of 1 (recess). Therefore, 1
By moving the secondary grooved tube 12 in the direction of arrow A in FIG. 1, the primary grooved tube 12 is rolled by a plurality of balls 9 that freely rotate at the same time as the balls 8 at the position of the grooved plug 6. Is applied and pressed against the grooved plug 6,
The groove 7 is formed by intermittently cutting the portion of the fin 15 of the primary grooved tube 12, and the inner surface of the primary grooved tube 12 corresponds to the shape of the groove 7 of the grooved plug 6. Next groove 13
Is formed, and the secondary grooved pipe 14 having the groove 11 and the groove 13 on the inner surface is formed.

Further, the secondary grooved tube 14 is used for the finishing die 1
The inner diameter grooved tube 23 is formed by reducing the diameter to a predetermined outer diameter by 8.

With the structure of the manufacturing apparatus for the inner grooved tube as described above, the rolling pressure is reduced especially by supporting the plurality of balls 8 and 9 of the rolling pressure applying means by the backup roll 20. Reduces the pulling force on the metal tube,
It has become possible to reduce the pull-out force and prevent the metal tube from breaking.

Further, by arranging the plurality of rolling pressure applying means in the same rotating body, it becomes possible to easily adjust the plurality of rolling pressure applying means in a short time. Cooling against frictional heat between the metal tube and the rolling pressure applying means can be easily performed.

The embodiment of the present invention has been described above.
The diameter of the grooved plug 6 to the apex of the groove 7 is equal to the diameter of the primary grooved pipe 12
The number, shape, and shape of the grooves 7 as long as the condition is larger than the inner diameter of the fins (projections) 15 inside and smaller than the diameter of the primary grooves (recesses) 11 within the primary grooved tube 12. The groove height may be any height. Further, a plurality of grooved plugs may be provided, and a plurality of grooved plugs can be arranged without improving the manufacturing apparatus, and the groove on the inner surface of the metal pipe can be easily made triple or more and the shape of the groove can be changed. It can change freely.

Further, as shown in FIG. 3, the backup roll 21 can be arranged in the first rolling pressure applying means, and the backup roll 22 can be individually arranged in the second rolling pressure applying means.
The outer diameter of the backup roll 22 is larger than the outer diameter of the backup roll 21, and the backup roll 21 is designed to rotate independently of each other.
A thrust bearing 19 having a small frictional force is interposed between the backup roller 22 and the backup roll 22.

According to this structure, the plurality of balls 9 are subjected to a rolling pressure from the outer peripheral surface to the primary grooved tube 12, and the primary grooved tube 12 is further contracted to reduce the primary groove. Tube 12
The inner surface is pressed against the grooved plug 6 to form the secondary groove 13.

Therefore, the diameter of the grooved plug 6 to the apex of the groove 7 may be smaller than the inner diameter of the fin (convex portion) 15 in the primary grooved tube 12, and the inner surface of the metal tube is further increased. The shape of the groove can be freely changed.

[0039]

As described above, according to the method and the apparatus for manufacturing an inner grooved tube of the present invention, by supporting the plurality of balls 8 and 9 of the rolling pressure applying means by the backup roll 20, Since the forming pressure becomes small, the pulling force on the metal pipe can be reduced and the pulling force can be made small to prevent the metal pipe from breaking. Further, by arranging the plurality of rolling pressure applying means in the same rotating body, it becomes possible to easily adjust the plurality of rolling pressure applying means in a short time. Cooling against frictional heat with the means can be easily performed.
Further, the degree of freedom in the shape and structure of the groove processing means is increased, so that the groove on the inner surface of the metal pipe can be easily made triple or more and the shape of the groove can be freely changed without improving the manufacturing apparatus. became.

[Brief description of drawings]

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

FIG. 2 is a schematic view showing an embodiment of a cross section of a rolling portion according to the present invention.

FIG. 3 is a schematic view showing an embodiment of an apparatus for manufacturing an inner grooved tube according to the present invention.

FIG. 4 is a schematic view showing an embodiment of a conventional apparatus for manufacturing an inner grooved tube.

[Explanation of symbols]

 1 Metal Tube 2 Floating Plug 3 Connecting Rod 4 Groove Plug 5 Groove 6 Groove Plug 7 Groove 8 Ball 9 Ball 10 Drawing Die 11 Primary Groove 12 Primary Groove Tube 13 Secondary Groove 14 Secondary Groove Tube 15 Fin 16 Rolling Tool 17 Rolling Tool 18 Finishing Die 19 Thrust Bearing 20 Backup Roll 21 Backup Roll 22 Backup Roll 23 Inner Grooved Tube 24 Reinforcement Ring 25 Shaft 26 Spacer 27 Rotating Head 28 Plug Unit

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

Claims (5)

[Claims] 1. A method of manufacturing an inner grooved tube having a groove on an inner wall surface, wherein a metal tube is moved in the tube axis direction, supported by a plurality of roll-shaped rotating bodies, and rotated at least in the tube axis direction. The rolling pressure is applied to the outer periphery of the metal pipe by the spherical body of, and the grooved plug or the protrusion plug contacting the inner wall surface is inserted inside the metal pipe at the position where the rolling pressure is applied. A method of manufacturing an inner grooved tube, characterized in that a groove is formed on the inner wall surface. 2. An inner surface grooved pipe manufacturing apparatus having a groove on an inner wall surface thereof, a moving means for moving a metal pipe in a pipe axis direction, a plurality of spheres, and a plurality of roll-like rotations for supporting the plurality of spheres. A rolling pressure applying unit configured to contact the outer circumference of the metal pipe with a plurality of spheres to apply a rolling pressure, and the inside provided in the metal pipe at the position of the rolling pressure applying unit. An inner surface grooved pipe manufacturing apparatus comprising groove processing means for contacting a wall surface to form a groove on the inner wall surface. 3. The inner surface according to claim 2, wherein the plurality of spheres and the groove processing means are provided at a plurality of positions in the tube axis direction to form multiple grooves on an inner wall surface of the metal tube. Grooved pipe manufacturing equipment. 4. The groove processing means is locked inside the metal pipe in a floating state, and is connected at a plurality of positions via small friction members such as thrust bearings. The manufacturing apparatus of the inner grooved tube according to claim 3. 5. The manufacturing apparatus for an inner grooved tube according to claim 3, wherein the plurality of spherical bodies and the plurality of roll-shaped rotating bodies are supported by one rotating body.