JPH02139108A - Copying method for inner wall of pipe and device therefor - Google Patents

Abstract

PURPOSE:To improve a cutting effect by cutting an inner wall of a pipe as copying a circumferential surface of a cutting head inclusive of a cutting edge after a form of the inner wall of the said pipe when cutting the pipe inner wall by relative rotation between the pipe and the cutting edge inserted into this pipe. CONSTITUTION:A rotary driver 11 is operated, rotating a face plate 12, and simultaneously with this, a feed gear 14 is moved to the left at constant speed, inserting a boring head 2 into a steel pipe A, and a cutting tool 3 cuts an inner wall of this speel pipe A by means of rotation of the steel pipe A and feed of the head 2. At a cutting process, the head 2 is held in the steel pipe A after a form of the inner wall of the steel pipe A by a copying shoe 6. In brief, even in the case where the inner wall is decentered and not in roundness, the head 2 is positioned right in the steel pipe A with the inner wall as a criterion. Accordingly, cutting allowance by the cutting tool 3 comes constant over the whole circumference of the inner wall, so that such uniform cutting that is nothing of any noncutting and over-infeed or the like is made possible and, what is more, surface roughness is also held down to the lowest possible extent.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method and apparatus for cutting the inner surface of a steel pipe, such as a seamless steel pipe, to smooth it.

[Conventional technology]

Depending on the use of steel pipes such as seamless pipes, it is necessary to remove minute flaws and wrinkles on the inner surface that occur during rolling, and for this purpose grinding with a grinder has been performed.

However, grinding with a grinder is inefficient, and continuous internal cutting with a cutting tool has been attempted.

On the other hand, processing of the inner and outer surfaces or chamfering of a steel pipe using a cutting blade is described, for example, in Japanese Patent Publication No. 46-20439.

JP-A No. 55-90201, Utility Model Application No. 57-1312
It is disclosed in Publication No. 1, etc.

[Problem to be solved by the invention]

However, seamless pipes have problems in that their outer and inner diameters are eccentric due to uneven thickness or slight bending during the manufacturing process, and sometimes the shape of the inner wall of the pipe is not necessarily a perfect circle. Moreover, the outer diameter, wall thickness, difference in wall thickness, etc. of seamless pipes are regulated by strict standards called API. On the other hand, if the above-mentioned conventional machining method using a cutting blade, which is mainly aimed at maintaining roundness after cutting, is applied as is, the inner diameter of the pipe will become true due to bending, cross-sectional distortion, etc. as described above. Since it is not a circle, the API standard could not be satisfied due to partial over-cutting or insufficient cutting due to empty cutting. Therefore, in the past, since cutting with a cutting blade was not suitable for seamless pipes, visual grinding with a grinder was exclusively performed as described above.

Therefore, when applying a cutting blade to cut the inner surface of a pipe such as a steel pipe, the present invention makes it possible to cut with a constant thickness along the inner diameter even if the inner diameter of the steel pipe is not a perfect circle, and to achieve good surface roughness. The aim is to find a way to finish the material at once, thereby significantly increasing cutting efficiency.

[Means to solve the problem]

In order to achieve the above object, the method for cutting the inner wall of a pipe according to the present invention includes the cutting blade inserted into the pipe when cutting the inner wall of the pipe by relative rotation between the pipe and the cutting blade inserted into the iron pipe. The cutting head is characterized in that cutting is performed while making the circumferential surface of the cutting head follow the shape of the inner wall of the tube.

Further, the apparatus used in this method includes a rotary drive device that holds one end of the tube and rotates it around its axis, a boring bar that can move back and forth in the axial direction of the tube, and a rotary drive device that is attached to the tip of the boring bar. a boring head that can be inserted into the tube, the boring head having a profiling chisel that can freely protrude and retract from the peripheral surface on the distal end side in the radial direction and biased toward the outside of the boring head, and a peripheral surface. The present invention is characterized in that it includes at least two fixing shoes protruding from the copying shoe, and further includes a cutting blade in the vicinity of the fixing shoe, which is provided at a position facing the copying shoe.

〔Example〕

Hereinafter, features of the present invention will be specifically explained with reference to embodiments shown in the drawings.

FIG. 1 shows an outline of the profile cutting device of the present invention.

In the figure, a rotary drive device 11 is disposed at one end of the bed 10, and the steel pipe is supported by a chuck 12a of a face plate 12 provided on a drive shaft 11a of the rotary drive device 11. A guide rail 10a is provided on the upper surface of the ped 10 so as to be parallel to the axis of the drive shaft 11a, and a pipe support frame 13 movable along the guide rail 10a and a feed device for cutting the inner surface of the steel pipe are provided. 14 are arranged respectively. The pipe support frame 13 is for supporting the steel pipe A in a rotatable manner. Further, a screw shaft 15 is built into the inside of the bed 10, and a pinion 14a that meshes with the screw shaft 15 is provided in the feeding device 14. When the screw shaft 15 is rotated by a drive device (not shown), the feed device 14 is moved left and right in the figure by a screw gear mechanism of the screw shaft 15 and the pinion 14a.

The boring bar 1 is attached to the feeding device 14 so that the axis of the steel pipe A substantially coincides with the axis of the steel pipe A.

In this installation, a floating holder 14 is used to facilitate attachment and detachment to the steel pipe and to protect the device.
It is preferable that the feeding device 14 be provided with the feeding device 14. In addition to feeding the boring bar 1 by running the feeding device 14,
If the device itself is equipped with a feeding mechanism so that the boring bar 1 can be fed out, the flow at the cutting point can be lengthened.

A boring head 2 is attached to the tip of the boring bar 1 for penetrating into the steel pipe and cutting the inner wall thereof. 2 is a side view of a portion of the boring head 2, and FIG. 3 is a partially cutaway view taken in the direction of arrow 1-1 in FIG. 2.

The outer diameter of the polling blade 2 is sufficiently smaller than the inner diameter of the steel pipe, and a cutting tool 3 is provided on the circumferential surface as a cutting blade at a distance from the tip, and the inner wall of the steel pipe A is cut with its tip 3a. Also, on the circumferential surface of the tip of the polling rod 2,
Fixed shoes a-4, 5 and one copying shoe 6 are provided, respectively. These fixed shoes 4.5 and copying shoes 6 are both made of cemented carbide.

One of the fixed shoes 4 is placed near the cutting tool 3 as shown in FIG. 3, and is screwed into the boring head 2.
4a. The direction of rotation of the steel pipe by the rotary drive device 11 is the direction of the arrow in FIG. 3, and the fixed shaft 5-4 is located behind the cutting point of the cutting tool 3. Note that the central angle θ formed by the cutting point of the tip 3a and the center of the fixing hole -4 is preferably approximately 15 degrees to prevent chips from escaping or being bitten. In addition, the other fixed shaft 5 is similarly fixed by a pole 5a, and in the illustrated example, the center angle formed with the mounting point of the fixed shaft 5-4 on the side of the cutting tool 3 is 9.
It is arranged at 0 degrees. It is preferable that the tips of these fixing shoes 4.5 are chamfered 4b, 5b so that they can be inserted into the steel pipe quickly.

Further, unlike the fixed shoe 4.5, the copying shoe 5-6 has a structure that can protrude and retract from the peripheral surface of the boring head 20 in the radial direction, and its position is opposite to the fixed shoe 5-4 on the side of the cutting tool 3. ing. In order to attach the copying sheath 5-6, a cylindrical mounting pusher s7a is incorporated into the boring head 2, and a restraining ring 7b that restricts the protrusion of the copying sheath 5-6 to the outside is attached by a pin 7c. It is fixed to the circumferential surface of the boring head 2. Copying machine: L-6 is a copying head 6a made of cemented carbide that is attached to a holding body 6 by a bolt 6b.
The holding body 6C forms a flange 6d that engages with the restraint ring 7b, and also has a mounting pusher 57.
A male screw 6e is formed in the portion that protrudes through the hole a. A nut 6f and a rotary nut 6g are screwed onto the male thread 6e to prevent the copying shoe 6 from falling off the mounting pusher x7a. Further, like the fixed shoe 4.5, a chamfer 6h is provided at the tip of the copying shoe 5-6.

Furthermore, a spring 8 is provided as an elastic body inside the mounting pusher 57a to bias the copying shoe 6 outward.

The spring 8 is a plurality of disk springs arranged and integrated, and springs with different numbers and spring constants are used depending on the magnitude of the urging force applied to the copying shaft L-6. Then, one end of the spring 8 abuts against the flange 6d of the holding body 6C, urging it outward.

Note that the adjustment of the biasing force of the spring 8 and the setting of the protrusion force of the copying head 6a are performed by the amount of screw engagement between the hollow 6f and the male screw 6e. In other words, when increasing the biasing force or decreasing the amount of protrusion of the protrusion pad 6a,
If 6f is screwed deeply (on the left side in FIG. 3), the holder 6C will be pulled toward the mounting push-piece L7a. Moreover, when applying the opposite conditions, it is sufficient to handle the screws by loosening them.

When inserting Rad 2 into the steel pipe, the third
As shown in the figure, the fixing shoe 5-4.5 and the copying shoe 6 each abut against the inner wall of the steel pipe A. During this cutting, the fixed sheath 5-4 located immediately behind the cutting point functions as a spacer for the chip 3a. That is, the fixing shoe 4 provides a certain distance between the tip 3a and the inner wall of the steel pipe, making it possible to perform cutting without the tip 3a cutting too far into the cutting surface. Furthermore, the spacer function of the fixed plate L-4 is effective in preventing chips from escaping or being caught in the chip 3a. In this way, the fixed shoe 4 creates the conditions particularly necessary for cutting with the tip 3a.

In addition, the other fixed shoe 5-5 has three parts including the copying shoe 6.
Provided to bring the boring head 2 into contact with the inner wall of the steel pipe with point support. In other words, assuming that the inner wall of the steel pipe is a perfect circle, it is preferable to support it at at least three points in order for the Pauling Rad 2 to rotate coaxially and relative to each other within the pipe A without shifting its center. be. and,
Since the center angle of the fixed sheath 5-5 is offset by a little more than 90 degrees with respect to the preceding cutting point, it also receives the main cutting force from the tip 3a. Furthermore, copying shoe 6
is always imitated by the biasing force of the spring 8.
is pressed against the inner wall to the steel pipe. Therefore, when the steel pipe A rotates in the direction of the arrow in FIG. 3, the copying shoe 6 moves in and out due to the elastic deformation of the spring 8 in response to the circumferential shape change of the inner wall of the steel pipe. Therefore, even if the inner wall of the steel pipe A is not a perfect circle or has irregularities, the copying shears 5-6 will move in and out following the inner wall, and the other fixed sheaths 4.
5 can be constantly pressed against the inner wall of the steel pipe A with a constant pressure.

Further, the fixed shear 5-4.5 and the copying sheath 5-6 are located closer to the tip than the cutting tool 3, as shown in FIG.

Therefore, when inserting the boring head J into the steel pipe A and cutting it, these fixed cylinders 5-
4.5 and the copying shoe 6 contact the inner wall to the steel pipe. Therefore, the boring head 2 scans the inner wall shape of the steel pipe A with the copying shoe 6, and the fixed shoes -4, -4,
5 is pressed against the inner wall of the steel pipe with a constant pressure, and at the same time, the bite 3 also comes into contact with the inner wall at a constant pressure.

By providing the copying shoe 6 in this way, even if the inner wall of the steel pipe is eccentric or has low roundness,
It becomes possible to perform cutting using the pole rad 2.

The procedure for cutting the inner wall of the steel pipe A using the cutting device having the above configuration will be explained with reference to FIG.

First, move the feeding device 14 to the left to set the boring head 2 to the retracted position, and then move the steel pipe A to the steel pipe support frame 1.
3 and hold one end with the chuck 12a of the face plate 12. After that, the rotary drive device 11 is operated to rotate the face plate 12.
is rotated, and at the same time, the feeding device 14 is moved to the right at a constant speed. The boring head 2 is inserted into the steel pipe by the movement of the feeding device 14, and the cutting tool 3 cuts the inner wall of the steel pipe A by rotating the steel pipe and feeding the rad 2 to the polling, and the inner wall is machined. be exposed.

In the cutting process, as already mentioned, the poling rod 2 is held in the steel pipe by the profiling shaft 6, following the shape of the inner wall of the steel pipe. In other words, even if the inner wall is eccentric or not perfectly round, the position of the boring head 2 within the steel pipe A is always determined based on the inner wall. Therefore, the cutting allowance by the cutting tool 3 is constant over the entire circumference of the inner wall, and it is possible to perform cutting without empty cutting or excessive cutting. Further, such cutting is possible not only on the vertical cross-sectional shape of the steel pipe A, but also even when bending or the like occurs in the axial direction. This is because the boring head 2 using the copying shoe 6 can move through the steel pipe while following the bending.

In this way, the poling tool 2 can be used to cut the steel pipe by following its inner wall, and compared to the conventional processing method using a grinder, the working time can be significantly shortened and productivity can be improved.

Moreover, since the inner wall is cut with a --like cutting allowance, surface roughness can also be kept low.

〔Effect of the invention〕

As explained above, in the present invention, the inner wall of a pipe such as a steel pipe is cut while moving the boring head to follow the shape of the inner wall. Therefore, even if the outer diameter and inner diameter of the tube are eccentric or the shape of the inner wall of the tube is not a perfect circle, cutting can be performed along the inner wall of the tube with a -like cutting allowance. Further, the cutting blade such as a cutting tool provided on the boring head does not make a blank cut or cut too far into the inner wall of the pipe, so that the blade does not drop off or the like. Therefore, the cut surface of the inner wall of the tube does not become rough, and a product with good surface roughness can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an outline of the cutting device used in the method of the present invention, Fig. 2 is a side view of the boring head portion, and Fig. 3 is a part seen in the direction of arrow I-1 in Fig. 2. It is a cutaway diagram. 1: Polling par 2: Polling spade 3: Bit (cutting blade) 3a: Chip 4.5: Fixed shoe 4a, 5a: Bolt 4b,
5b: Chamfer 6: Copying head 6a: Copying head 6b: Port 6c holding body 6d: Flange 6e: Male thread
6f: Nut 6g = Lock nut 6h: Chamfer 7a: Mounting bush 7b = Restriction ring 7C: Bolt 8 Spring 10: Bedding 10
a Ni guide rail 11: Rotation drive device 11a: Drive shaft 12: Face plate 12a: Chuck 13:
II pipe support frame 14: Feeding device 14a: Pinion 14b: Floating holder 15 Varnish screw - Shaft: Steel pipe

Claims (1)

[Claims] 1. When cutting the inner wall of the tube by relative rotation between the tube and the cutting blade inserted into the tube, the peripheral surface of the cutting head including the cutting blade is adjusted to the shape of the inner wall of the tube. A method for cutting the inner wall of a pipe by cutting it while following the pattern. 2. A rotary drive device that holds one end of the tube and rotates it around its axis; a boring bar that can move forward and backward in the axial direction of the tube; and a boring bar that is attached to the tip of the boring bar and that can be inserted into the tube. a boring head, the boring head includes at least two profiling shoes that are retractable in the radial direction from the circumferential surface on the tip side and biased toward the outside of the boring head, and at least two fixed shoes that protrude from the circumferential surface. A pipe profiling cutting device further comprising a cutting blade near a fixed shoe provided at a position opposite to the profiling shoe.