JPH0446712A - Processing method for threaded joints at pipe ends - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to the removal of burrs generated on incomplete threads when cutting a threaded joint at the end of a pipe.

[Prior Art] Seamless pipes and the like used as oil country tubular goods are connected by tapered threaded joints formed at the ends of the pipes. These threaded joints need to be finished with high precision from the viewpoint of airtightness, and normally the thread cutting operation is numerically controlled using an NC thread cutter exclusively used for processing threaded joints at the end of pipes, resulting in high efficiency and high precision. I'm trying to process it. FIGS. 3 and 4 show an NC thread cutter exclusively for machining threaded joints at the ends of such pipes.

The screw spike 21 is composed of a main shaft 23 that holds the tubular body 1 at a desired position and rotates the tubular body 1, and a tool rest 2 and an inner support 27 that thread the end of the tubular body 1. has been done. The tubular body 1 is held by the main shaft 23 by a chuck 25.25 provided at the end thereof.
The rotation is performed by an internal rotation drive means. Further, the tool post 2 has a plurality of bits 3 for screw machining, and is freely moved in the X-axis direction and the Z-axis direction by DC servo motors Dx and Dz. Furthermore, the inner support 27 supports the tube end from the inner surface to ensure centering of the tube end.

The tool rest 2 can be rotated in the horizontal direction about a central axis 28, as shown in FIG. A cutting tool mounting seat 4 is provided on each side of the tool rest 2, and the cutting tool 3 is mounted on this mounting seat 4. The cutting tools 3 are used for different purposes, such as for rough cutting and finishing, or for internal and external threads. Rotate the tool rest 2 according to the NC program and select the tool 3 that suits your purpose. Thread processing is continuously performed on the tube body 1.

By the way, as shown in FIG.
2 and the end portion 13 of the cut are formed with incomplete threads. Burrs are generated at the cut start portion 12 and the cut end portion 13, which are the incomplete thread portions. This burr is threaded joint 11
Tightening sometimes causes galling and seizure, which must be removed. Conventionally, this burr removal was done manually by a worker using a grinder, various files, various wheels, etc. at a screw inspection site after removing the threaded pipe body 1 from the thread cutting V & 21. .

[Problems to be Solved by the Invention] The above-described conventional method for removing burrs generated on incomplete threads has the following problems.

(1) It takes time to remove burrs, and it is difficult to improve the threading efficiency of the tube body.

(2) The accuracy of deburring varies from person to person, and it cannot be said that burrs are completely removed.

(3) Therefore, there are problems in manufacturing cost and quality.

This invention solves the above-mentioned problems, and provides a threaded joint at the end of a pipe in which the burrs that occur on the threaded joint of the pipe body can be completely removed automatically, with high efficiency, and without relying on manual labor by workers. The purpose is to provide a processing method.

[Means for Solving the Problems] A threaded joint machining method for a pipe end according to the present invention is a method for machining a threaded joint at a pipe end using a blade that moves along the longitudinal direction of the pipe according to an NC program. In the joint processing method, a deburring tool provided on a tool post is operated according to an NC program to remove burrs generated on incomplete threads at the cutting start and cutting end of a threaded joint.

[Function] The method of processing a threaded joint at the end of a pipe according to the present invention operates a deburring tool provided on a tool rest according to an NC program to remove burrs from incomplete threads at the beginning and end of cutting of a threaded joint. Remove any burrs. Therefore, deburring is automatically performed within the thread cutting machine and as part of the thread cutting process, thereby increasing the efficiency of deburring and thus the thread processing efficiency. Further, since the deburring is performed using a burr collecting tool provided on the tool rest, the deburring is always constant, and the deburring accuracy remains at a high level without variation, and the dimensional accuracy of the threaded joint is not impaired.

[Example 1] An example of the method for manufacturing a threaded joint at the end of a pipe according to the present invention will be described with reference to the drawings. FIGS. 1 and 2 are explanatory diagrams showing the implementation status of one embodiment of the method for processing a threaded joint at a pipe end according to the present invention. Processing of the threaded joint 11 of the tube body 1 itself is carried out as before using various tools 3 mounted on the tool post 2.Next, a fine abrasive wheel 6 is rotated by an air grinder 5 mounted on one of the tool mounting seats 4. Then, burrs generated on the incomplete threads are removed using a coarse abrasive wheel 7 and a special deburring tool 9 according to an NC program.

That is, the burr generated at the cutting start portion 12 can be removed by the deburring tool 9 while being controlled by the NC program, since the position in the circumferential direction can be specified.

However, fine burrs (
The burrs on the parts where the height of the incomplete threads are low cannot be removed with the deburring tool 9, so the air grinder 5 is used to remove the burrs.
The remaining burrs are removed using a fine abrasive wheel 6 attached to the tip. Note that since the cutting start portion 12 is a cutting surface,
Coarse grain abrasive wheels may leave abrasive grain marks and reduce the product value in terms of appearance, so fine grain abrasive wheels6 are used.
use.

The burr that occurs at the cutting end part 13 is a burr that occurs in the black skin part of the tube, and because the outer diameter of the tube body 1, degree of bending, surface texture, etc. are different, it is difficult to identify the location where it occurs and it is difficult to cut. Since it cannot be removed properly with a tool, it is removed with a coarse abrasive wheel 7 that is resistant to wear.

Air grinder 5 with the above abrasive wheel attached
It is designed to rotate with compressed air of 4 to 5 kg/cm2. The supply of compressed air to the air grinder 5 is performed by automatically opening and closing a valve in accordance with an instruction based on an NC program.

Also, the rotation direction of the air grinder 5 and the rotation direction of the tube body 1 may be the same or different, but if the rotation directions are the same, the burr removal efficiency will be higher than when the rotation directions are opposite. improves.

Note that the wheel attached to the air grinder is not limited to an abrasive wheel, and a wire brush, a brush with abrasive grains, or the like may be used.

According to the present invention, the efficiency of cutting pipe threads has increased from the conventional 16 threads/hour to 22.5 threads/hour, which is an approximately 40% increase in efficiency.

[Effects of the invention] The present invention not only improves the processing efficiency of threaded joints for pipe bodies, but also enables reliable deburring without compromising the dimensional accuracy of threaded joints, which in turn improves productivity and economic efficiency. It has excellent effects, such as being able to streamline personnel operations.

[Brief explanation of drawings]

FIGS. 1 and 2 are explanatory diagrams showing the implementation status of one embodiment of the threaded joint processing method for the pipe end of the present invention, and FIGS. 3 and 4 are side views showing NC thread cutting young panicle preparation. A front view, FIG. 5 is an enlarged plan view showing the tool rest, and FIG. 6 is an explanatory view showing a partial cross section of the threaded joint. 1. Pipe body, 2.. Turret post, 3. Various bits, 5. Air grinder, 6. Fine abrasive wheel, 7.. Coarse abrasive wheel, 9) Special tool for chamfering, 1. Threaded joint part. , 12 Start of cutting of threaded joint, 13... End of cutting of threaded joint.

Claims (1)

[Claims] In a threaded joint processing method in which a threaded joint is cut at the end of a pipe with a blade that moves along the length of the pipe according to an NC program, a deburring tool installed on the tool rest is operated according to the NC program to cut the threaded joint. A method for processing a threaded joint at the end of a pipe, characterized by removing burrs generated on incomplete threads at the beginning and end of the cut.