JPH10272519A - Manufacturing method of dimple tube - Google Patents

Abstract

(57) [Problem] To produce a dimple tube with high productivity by forming a substantially uniform dimple without uneven wall thickness. SOLUTION: A mandrel 42 having a concave portion (concave groove 42a) for dimple processing formed on the outer surface is inserted into a hollow portion of a pipe A to be processed, and a convex portion (ball 57a) for dimple processing is formed on the outer surface. Are formed so as not to be in contact with each other in the circumferential direction of the pipe to be processed, and each roll is so placed that the outer peripheral surface of each roll is in contact with the pipe to be processed and moves substantially in the axial direction of the pipe to be processed. While rotating, the roll is moved in a direction intersecting with the axis of the pipe to be processed, and the roll and the pipe to be processed are relatively moved in the axial direction while being pressed against a portion of the pipe to be processed corresponding to the mandrel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called dimple tube (for example, an absorption refrigeration cycle such as an absorption refrigerator or an absorption heat pump) having a depression or a projection (hereinafter referred to as dimple) formed on the outer or inner surface of the tube. Heat transfer tubes and the like used in the present invention).

[0002]

2. Description of the Related Art In order to improve the heat transfer performance of a heat transfer tube,
There is one in which a large number of dimples which are concave on the outer surface of the tube and project on the inner surface of the tube are formed in the heat transfer tube (JP-A-6-307788).

As a method for manufacturing such a heat transfer tube, as shown in FIG. 3, a rod-shaped mandrel 2 having a plurality of axially parallel grooves 2a formed on the outer peripheral surface thereof is inserted into a hollow portion of a tube 1 to be processed. Then, there is a method in which three disks 3, 4, 5 on which a large number of protrusions 3a, 4a, 5a are formed in the circumferential direction are pressed against the outer peripheral surface of the work tube 1 corresponding to the mandrel 2 while rotating.

As another manufacturing method, as shown in FIG. 5, a plate 6 is fed by a feed roll 7, and a roll 8 having a large number of projections 8a on the outer peripheral surface and a large number of grooves 9a on the outer peripheral surface are formed. There is a method in which the plate material 6 is formed into an uneven plate 10 by passing through the formed roll 9, the uneven plate 10 is formed into an annular shape by a tube forming machine 11, and a joint portion is welded to produce a dimple tube 12.

[0005]

However, in the conventional method of manufacturing a heat transfer tube shown in FIG. 3, the clearance between the disks 3, 4, 5 and the mandrel and the mutual distance are determined according to the wall thickness and the feed speed of the tube 1 to be processed. If you do not fine-tune the positional relationship,
A dimple having a uniform thickness as shown in FIG. 4A cannot be formed. Therefore, if this adjustment is incomplete, the meshing relationship between the parallel groove 2a and the projections 3a, 4a, 5a will be defective, and the thin portion 1a and the thick portion 1b are formed as shown in FIG. Is done. In an extreme case, there occurs a defect that the thickness of the thin portion 1a becomes smaller than the minimum design limit.

On the other hand, since the rotation direction of the outer peripheral surfaces of the disks 3, 4, and 5 is substantially perpendicular to the moving direction of the pipe 1 to be processed, there is a limit in increasing the processing speed and the productivity is poor. .

In the conventional method for manufacturing a heat transfer tube shown in FIG.
Although the problems shown in FIG. 3 can be considerably solved, when the heat transfer tube is used in an absorption refrigerator, the aqueous solution of lithium bromide used as the absorbing solution has a strong corrosive property, so that corrosion occurs at the welded portion. And may lack reliability.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is capable of forming a substantially uniform dimple without uneven thickness, and capable of manufacturing a dimple tube with high productivity. It is an object of the present invention to provide a method for producing the same.

[0009]

According to a method of manufacturing a dimple tube of the present invention, a mandrel having a concave or convex portion for dimple processing formed on an outer surface is inserted into a hollow portion of a tube to be processed. A plurality of rolls on which a convex portion or a concave portion for dimple processing is formed are positioned so as not to be in contact with each other along the circumferential direction of the pipe to be processed, and the outer peripheral surface of each roll is in contact with the pipe to be processed. While rotating each of the rolls so as to move substantially in the axial direction of the pipe to be processed, the roll is moved in a direction intersecting with the axial direction of the pipe to be processed to move the roll into a portion of the pipe corresponding to the mandrel. While pressing
The roll and the pipe to be processed are relatively moved in the axial direction.

In addition to the plurality of rolls, a plurality of other rolls having a convex or concave portion for dimple processing formed on an outer surface thereof are positioned so as not to contact each other along the circumferential direction of the pipe to be processed. The direction intersecting the axis of the pipe to be processed while rotating the other rolls so that the outer peripheral surface of each of the other rolls is in contact with the pipe to be processed and moves substantially in the axial direction of the pipe to be processed. The other roll may be moved to press against a portion of the pipe to be processed corresponding to the mandrel and not interfering with the dimple formed by the plurality of rolls.

[0011] The plurality of rolls or the plurality of other rolls may be pressed and retracted with respect to the pipe to be processed, so that a processed portion and an unprocessed portion of the dimple may be formed alternately and continuously.

As an example of an apparatus for carrying out the method for manufacturing a dimple tube, a mandrel inserted into a hollow portion of a tube to be processed and the mandrel provided corresponding to a mandrel in the tube to be processed are provided. A roll pressed against the outer peripheral surface of the pipe while rotating, and a driving device for moving the pipe to be processed in the axial direction, and a concave portion for dimple formation on at least one of the outer peripheral face of the mandrel or the outer peripheral face of the roll. Or a dimple tube manufacturing apparatus in which a convex portion is formed, wherein the rolls are formed from a plurality of rolls, and each of the rolls has a predetermined shape so as not to contact with each other along a circumferential direction of the pipe to be processed. The rolls are arranged at intervals and supported so as to be movable toward or away from the pipe to be processed, and each of the rolls has an outer peripheral surface in contact with the pipe to be processed and substantially the same as the pipe to be processed. It is preferably connected to a rotary drive mechanism for rotating so as to move in the linear direction.

[0013] Further, the plurality of rolls constitute one set, and a plurality of rolls are arranged along the length of the pipe to be processed.
It is preferable that the phases of the rolls of each set are centered around the axial direction of the pipe to be processed, and are shifted from each other for each set.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing a dimple tube according to an embodiment of the present invention will be described below.

This manufacturing method comprises the following steps.
That is, the mandrel 42 in which the concave groove 42a which is a concave portion for dimple processing is formed on the outer surface is inserted into the hollow portion of the pipe A to be processed. A plurality of rolls 5 provided with a plurality of balls 57a which are convex portions for dimple processing on the outer surface
7 are positioned so as not to contact each other along the circumferential direction of the pipe to be processed. Each of the rolls 57 is arranged such that the outer peripheral surface of each of the rolls 57 comes into contact with the pipe A to be processed and moves substantially in the axial direction of the pipe A to be processed.
Is driven to rotate. Each roll 57 is moved in a direction intersecting with the axial direction of the pipe A to be processed, and is pressed against a portion of the pipe A to be processed corresponding to the mandrel 42. At the same time, the workpiece A is moved in the axial direction.

More specifically, as shown in FIG. 2, the tip of the pipe A to be processed is reduced in diameter by a press device, and a plug 40 is inserted into the hollow portion of the pipe A to be processed. Then, the distal end of the pipe A to be processed is gripped by the chuck 21 through the die hole 31 a of the drawing die 30, and is pulled in the axial direction by the pulling device 20. As a result, the floating plug 44 of the plug 40 is located in the die hole 44a, the pipe A to be processed is pulled out by the drawing die 30, and the outer diameter is reduced.

After a certain length is pulled out, the pipe A to be processed is transferred to the belt feeder 21 and the dimple forming apparatus 5.
Pass through 0 and pull out further. In the dimple forming apparatus 50, as shown in FIG. 1, the shaft 56 is rotated by the rotation driving mechanism, and the rods 58 and 59 are moved in a direction orthogonal to the axial direction of the shaft 56, so that the circumference of the pipe A to be processed is changed. The four rolls 57 arranged in the directions are moved toward the pipe A to be processed and pressed against the outer peripheral surface of the pipe A to be processed. Thus, the pipe A to be processed is sandwiched between the mandrel 42 of the plug 40 and the roll 57, and a dimple having a concave outer peripheral surface and a convex inner surface is formed by the concave groove 42a and the ball 57a.

At this time, the ball 57a of the roll 57 is arranged corresponding to the concave groove 42a of the mandrel 42. When the roll 57 is pressed by the pipe A to be processed and the dimple is formed, the ball 57a of the pipe A The dimple projecting from the inner surface fits into the concave groove 42a of the mandrel 42. This allows
The concave groove 42a of the mandrel 42 is the ball 57 of the roll 57.
a, the mandrel 42 is automatically aligned by the pressing of the rolls 57, and the ball 57a
Is securely fitted in the concave groove 42a, and a dimple having a substantially uniform thickness is formed.

Since the rolls 57 are located at predetermined intervals so as not to contact each other, each rod 5
The bearings 54, 55 can be operated by operating
Are moved independently of each other, whereby each roll 57 can be moved closer to or away from the pipe A to be processed. Thereby, the amount of pressing of the roll 57 against the pipe A to be processed can be adjusted, for example, the degree of dimple processing can be finely adjusted, and processing corresponding to the material of the pipe A to be processed can be performed.

Further, when the pipe A to be processed is being pulled out, each roll 57 may be repeatedly pressed and retracted on the pipe A to be processed. As a result, a portion where the dimple is processed and a portion where the dimple is not processed are intermittently formed in the pipe A to be processed in the axial direction.

Each roll 57 is rotated so that the outer peripheral surface thereof is in contact with the pipe A to be processed and moves substantially in the axial direction of the pipe A to be processed. The dimple is reliably and accurately formed following the movement of A. Therefore, the productivity of the production of the dimple tube can be dramatically increased.

Each roll 57 is provided in a plurality of stages along the pulling-out direction, and a portion which does not interfere with the dimple formed by each roll 57 in the preceding stage is pressed by each roll 57 in the subsequent stage. By the drawing, dimples are formed over the entire circumference of the pipe A to be processed.

In the method of manufacturing a dimple tube according to this embodiment, a mandrel 42 having a concave groove 42a is formed.
And a roll 57 provided with a ball 57a as a convex portion, the dimple is formed. However, a mandrel having a convex portion on the outer peripheral surface and a roll having a concave portion on the outer peripheral surface are used. The dimples may be formed by using them.

It should be noted that as the apparatus for carrying out the above-mentioned method for manufacturing a dimple tube, various structures can be used. In order to facilitate understanding of the manufacturing method, a specific example will be described below. Is described.
As shown in FIG. 2, a pulling device 20 for pulling out a pipe A to be processed.
And a dice 30 for reducing the diameter of the pipe A to be processed, a plug 40 inserted into a hollow portion of the pipe A to be processed, and a dimple forming apparatus 50 for forming dimples on the inner and outer surfaces of the pipe A to be processed. Be composed. The towing device 20 grips the end of the pipe A to be processed by the chuck 21 and pulls the pipe A in the horizontal direction in the drawing, for example, using a hydraulic cylinder or the like as the pulling power. In this embodiment, a belt feeder 21 for feeding the pipe A to be processed in the pulling direction is provided. The belt feeder 21 is a pipe A to be processed.
Is provided to assist in smoothly supplying the dimples to the dimple forming apparatus 50. The drawing die 30
It is provided on the upstream side in the drawing direction and reduces the diameter of the pipe A to be processed. This drawing die 30 has a die hole 3
It comprises a die body 31 made of cemented carbide in which 1a is formed, and a die box 32 that supports the die body 31. The plug 40 is inserted into the pipe A to be processed, and includes a mandrel 42 disposed at a position corresponding to the dimple forming device 50, a tie rod 43 integrally connected to the mandrel 42, and a tie rod 43. And a floating plug 44 connected integrally. The mandrel 42 has a groove 42 on the outer peripheral surface in the axial direction.
a are formed in large numbers. Floating plug 44
Is provided with a conical tapered portion 44a corresponding to the die hole 31 of the die body 31, and a columnar portion 44b connected to the conical tapered portion 44a.

As shown in FIG. 2, in the dimple forming apparatus 50, a plurality of flat plates 51 fixed to a base (not shown) are arranged in a plurality of stages along the drawing direction of the pipe A to be processed. You. As shown in FIG. 1, each of the plates 51 is formed with a substantially rectangular window portion 52 in a plan view. Four windows 52 are formed. The four windows 52 communicate with each other at the center of the plate 51 and
3 are formed. This communication part 53 is also formed penetrating the plate 51. A pipe A to be subjected to dimple processing is inserted into the central portion of the communication portion 53 so as to be orthogonal to the plate surface of the plate 51. Bearings 54 and 55 are attached to the window 52 of the plate 51, and a shaft 56 is rotatably supported by the bearings 54 and 55. A roll 57 that is pressed against the pipe A to be processed is fixed to the tip of the shaft 56. The shaft 56 is connected to a rotation drive mechanism (not shown) including, for example, an electric motor and a hydraulic motor. Each shaft 56 provided on each window 52 is rotated synchronously by the rotation drive mechanism. Each roll 5
7 comes into contact with the outer surface of the pipe A to be processed,
The pipes A are arranged so that their mutual angles are 90 ° around the axial direction of the pipe A to be processed so as not to contact each other.
Each roll 57 is composed of a number of balls 57 having a radius of 1 mm.
a are arranged in two rows at a pitch of 2 mm in the circumferential direction. Each of the bearings 54 and 55 can move in a direction orthogonal to the shaft 57. By driving rods 58 and 59 connected to the bearings 54 and 55 in a direction orthogonal to the shaft 56, 54 and 55 can be moved together with the shaft 57 in this direction. The rolls 57 disposed on the respective plates 51 are formed around the axial direction of the pipe A to be processed in order to form dimples at positions not interfering with the dimples processed by the rolls 57 provided on the preceding plate 51. The phase is shifted from each other for each stage (each set).

[0026]

As described above, in the method for manufacturing a dimple tube according to the present invention, a substantially uniform dimple can be formed without uneven thickness, and the dimple tube can be manufactured with high productivity. Is obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing an apparatus used for a method for manufacturing a dimple tube according to an embodiment of the present invention.

FIG. 2 is an overall configuration diagram showing an apparatus used for a method for manufacturing a dimple tube according to an embodiment of the present invention.

FIG. 3 is a view showing an apparatus according to a conventional method for manufacturing a heat transfer tube.

FIG. 4 is a cross-sectional view showing a part of a conventional heat transfer tube.

FIG. 5 is a view showing an apparatus according to a conventional method for manufacturing a heat transfer tube.

[Explanation of symbols]

 Reference Signs List 20 Traction device 42 Mandrel 42a Groove (concave portion) 57 Roll 57a Ball (convex portion) A Pipe to be processed

Claims (3)

[Claims] A mandrel having a concave or convex portion for dimple processing formed on the outer surface thereof is inserted into a hollow portion of a pipe to be processed, and a convex or concave portion for dimple processing is formed on the outer surface. The plurality of rolls are positioned so as not to be in contact with each other along the circumferential direction of the processed pipe, and each of the rolls is in contact with the processed pipe so that the outer peripheral surface of each roll is moved substantially in the axial direction of the processed pipe. While rotating the roll, the roll is moved in a direction intersecting with the axial direction of the pipe to be processed, and pressed against a portion of the pipe to be processed corresponding to the mandrel. A method for manufacturing a dimple tube, comprising: 2. In addition to the plurality of rolls, a plurality of other rolls having a convex portion or a concave portion for dimple processing formed on an outer surface thereof are not in contact with each other along the circumferential direction of the pipe to be processed. While rotating the other rolls so that the outer peripheral surface of each of the other rolls is in contact with the pipe to be processed and moves substantially in the axial direction of the pipe to be processed, while rotating the other rolls in the axial direction of the pipe to be processed. 2. The dimple tube according to claim 1, wherein the other roll is moved in an intersecting direction to press a portion of the tube to be processed corresponding to the mandrel, the portion not interfering with a dimple formed by the plurality of rolls. Method. 3. A processing part and a non-processing part of a dimple are formed alternately and continuously by pressing and retreating the plurality of rolls or a plurality of other rolls with respect to the pipe to be processed. A method for producing the dimple tube described above.