JPH0429441B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for manufacturing a metal tube having a plurality of continuous grooves or protrusions on the inner surface (hereinafter referred to as an inner surface processed tube), and particularly a metal tube that is inserted into the inner surface of the tube to determine the inner surface shape. This invention relates to an improvement in the holding method of a grooved plug.

The inventors have previously proposed a method for producing an internally processed pipe, in which a predetermined grooved plug is provided in the pipe before drawing while feeding the pipe in the axial direction, and the grooved plug is We proposed a method of compressing the outer periphery of a pipe using a plurality of planetary rotating rolls. This method has the advantage that it is possible to easily obtain a pipe with a smooth outer surface and a more accurate inner diameter. However, since this method of grooving uses a mandrel to support a grooved plug for internal machining, there is a limit to the length of pipe that can be machined, and long products exceeding 10 m can be processed continuously. You can't get it.

The present invention has been made in view of the above-mentioned problems in order to provide an apparatus that can continuously obtain long inner-surface processed pipes.

According to the present invention, this purpose is achieved by connecting a grooved plug for inner surface processing to a floating plug that cooperates with the drawing die to shrink the pipe to be processed, so that the pipe passing through the drawing die is A plurality of rotary processing members are rotatably held at predetermined positions in the pipe to be processed, and rotate planetarily while contacting the outer peripheral surface of the pipe passing through the part where the grooved plug is located. This can be achieved by pressing the grooved plug onto the grooved plug.

In this case, the portion of the floating plug in front of the bearing portion must be larger than the hole diameter of the drawing die that cooperates with the floating plug to contract the pipe to be processed. It is desirable to use a rod that connects the floating plug and the grooved plug for internal processing with a diameter that is equal to or smaller than the diameter of the bearing portion of the floating plug. The relationship between the connecting rod and the grooved plug is such that it is rotatable so that when a rotational force is applied to the grooved plug, it can be absorbed.

Hereinafter, one embodiment of the apparatus according to the present invention will be described with reference to the drawings.

A tube 1 of circular cross-section, for example a copper tube, obtained by extrusion and subsequent drawing, is continuously fed through a straightening device (not shown), a first drawing die 2, a compression device 3 and a second drawing die. It is drawn through the die 4 and internally processed at the compression device 3. Then, the inner surface processed pipe 11 is taken up by a take-up device (not shown) and cut into a regular length or continuously wound up.

The compression device 3 includes a rotary head 31, a device for supporting it, and a drive device. In the rotary head 31 of the compression device 3, a plurality of rotary processing members, for example three rolls 32, which rotate planetarily are arranged at equal intervals on the same circumference. Each roll 32 is supported by a pawl 33 of a rotary head 31 so as to be rotatable about its own axis, and the pawls 33 can simultaneously move in the direction perpendicular to the axis, similar to a scroll chuck. Therefore, if the inscribed circle of each roll 32 is set to a predetermined size, each roll 32 is brought into contact with the outer surface of the tube 1, and the head 31 is driven to rotate, each roll 32 will move on the outer surface of the tube 1. Rotating and revolving around its axis, tube 1
can be pressed onto the grooved plug 34 without difficulty.

A grooved plug 34 providing a continuous groove or protrusion 12 on the inner surface of the tube 1 is located inside the tube 1 at the location where each roll 32 is located. The grooved plug 34 has a predetermined shape, for example, a plurality of spiral grooves or protrusions on its surface, and is rotatably attached to the tip of the connecting rod 5. The other end of the connecting rod 5 is connected to a floating plug 21 that cooperates with the first drawing die 2 to shrink the tube 1.
Therefore, the grooved plug 34 is supported by the floating plug 21 via the connecting rod 5, and during grooving,
It is always held in a predetermined position within the tube 1 that has passed through the drawing die 2.

The floating plug 21, the connecting rod 5 and the grooved plug 34 are inserted into the distal end of the tube 1 prior to machining, and the floating plug 21 is set so as to engage with the drawing die 2 during machining.

In this arrangement, if the rotary head 3 is rotated at high speed in a certain direction while moving the tube 1, the tube 1 passing through the compression device 3 will be rotated by the planetary rolls 32 while in contact with its outer surface. Since it is pressed onto the grooved plug 34, the outer shape of the grooved plug 34 is continuously transferred to the inner surface, and a predetermined groove or protrusion 12 is formed. In this case, grooved plug 3
4 is connected and supported by the floating plug 21, there is no limit to the length of the pipe 1, and even long pipes 1 exceeding 10 m can be processed continuously.

During machining, forward force and rotational force act on the grooved plug 34, but since the plug 34 is rotatably supported by the connecting rod 5, the grooved plug 34 escapes them and is applied to the inner surface of the pipe. There is no deformation of the formed grooves or protrusions 12.

As the rolls 32 revolve, a twisting force acts on the tube 1, but this is suppressed by friction with the drawing dies 2, 4, etc., and is therefore small. The twisting force acting on the tube 1 can be eliminated or reduced by arranging another similar head close to the head 31 and rotating each head in opposite directions.
In this case, the plug 34 is also interposed at a position related to each roll in another head added nearby, and of course presses the pipe 1 passing therethrough. In this way, higher reduction can be obtained and difficult-to-process pipes can be easily processed.

By performing the groove machining as described above, a predetermined inner surface processed pipe 11 can be continuously obtained without being limited by the length of the pipe 1.

By subsequently passing the inner surface processed tube 11 through the second die 4 and drawing it out, the outer diameter can be made more accurate and the surface can be made smoother.

In addition, the reductions of each part in continuous processing as in the examples should be distributed so that the sum is the upper limit of the reduction that can be applied to a pipe in general drawing processing, for example, about 40% or less in the case of copper pipes. is desirable.

As is clear from the above description, the apparatus of the present invention is capable of performing inner surface processing by compressing a pipe to be processed onto a grooved plug using a plurality of rotating processing members that rotate planetarily. Since the grooved plug is connected to the floating plug to maintain its position, there is no limit to the length of the pipe to be processed, and long internally processed pipes can be easily processed using a simple device. It has the advantage of being able to be manufactured continuously, and its industrial value is extremely large.

[Brief explanation of drawings]

The figure is an explanatory diagram showing an embodiment of the apparatus according to the present invention. 1: Pipe, 2 and 4: Drawing die, 3: Compression device, 21: Floating plug, 31: Rotating head, 32: Roll, 33: Claw, 34: Grooved plug, 5: Connecting rod, 11: Internal processing Tube, 12: Groove or protrusion.

Claims (1)

[Claims] 1 A drawing die, a floating plug that cooperates with the drawing die to contract a pipe to be processed passing through the drawing die, and a connecting rod connected to the floating plug and extending toward the advancing side of the pipe to be processed. A grooved plug for inner surface machining is rotatably supported at the tip, and the grooved plug is arranged on the outer periphery of the part where it should be located and rotates planetarily while contacting the outer peripheral surface of the pipe to be processed passing through the said part. and a plurality of rotary processing members for compressing the pipe onto the grooved plug.