JPS6141685B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for cutting steel pipes or solid round steel (hereinafter referred to as steel pipes, etc.) using a milling cutter.

The following three methods are known for cutting steel pipes using conventional milling cutters. 1. Steel pipe cut-off cutting method, in which the steel pipe is fixed and a cutting feed is applied to a rotating milling cutter to cut off the steel pipe (see Figure 1); 2. The steel pipe is rotated against a rotatably held steel pipe. A relative rotation cutting method in which the cutting feed is applied to the milling cutter to cut through the pipe wall, and then the feed of the milling cutter is stopped and the steel pipe is cut by approximately 5/6 rotation (see Figure 2).
3 Simultaneous relative rotational cutting in which the steel pipe B, which is rotatably held as shown in Fig. 3, is rotated and cutting feed is applied to the rotating milling cutter to progressively cut the steel pipe B along spiral cutting trajectories C and D. The method (see Figure 3) is known.

In the case of the parting cut shown in FIG. 1, a milling cutter is required in which the diameter of the cutter A is about three times larger than the outer diameter of the pipe B to be cut, which has the disadvantage that the device becomes large and expensive.

In the case of the relative rotational cutting shown in FIG. 2, the milling cutter A may have a small diameter that is approximately equal to the outer diameter of the pipe B to be cut, but is subject to restrictions on the length of the cutting arc. For this reason, the milling cutter must be replaced depending on the tube diameter and wall thickness, which makes the operation complicated and reduces cutting efficiency.

In the case of a milling cutter, cutting is performed while the cutting pieces are accommodated between the blades, so the amount of cutting is limited by the cutting piece accommodation space formed between the blades. It is impossible to cut an amount that exceeds the amount of cutting chips that can be accommodated between the blades. Normally, the relationship between the cutting arc length and the number of effective teeth touching it (the number of simultaneous cutting teeth) is inversely proportional when the cutting feed rate is constant. is used interchangeably.

In the case of simultaneous relative rotation cutting as shown in Fig. 3, since the cutting arc length is small, a wide variety of steel pipes with different pipe diameters and wall thicknesses can be cut with the same milling cutter.
Although the milling cutter does not require replacement, there are problems in that it takes time to complete cutting and cutting efficiency is low.

The present invention solves all of the drawbacks of the conventional methods described above, and involves applying feed to the milling cutter and relative rotation between the milling cutter and the steel pipe after the milling cutter has cut the maximum allowable depth of cut. In this method, the steel pipe is progressively cut in a pseudo-spiral shape to break the pipe wall, then the cutter feed is stopped, and the steel pipe is completely cut by relative rotation between the cutter and the steel pipe. This allows the pipe diameter to be adjusted using the same milling cutter.
It is possible to provide a highly efficient and versatile steel pipe cutting method that can efficiently cut a wide variety of steel pipes with different wall thicknesses.

This will be explained below with reference to FIG. 4 and subsequent figures. FIG. 4 explains the principle of the present invention, in which a milling cutter A (actually, a plurality of milling cutters are used) is capable of cutting toward the center of a steel pipe B to be cut. Further, the steel pipe B to be cut can be rotated in the Y direction, and the milling cutter A can be rotated in the X direction. When cutting the steel pipe B to be cut, the milling cutter A is rotated in the X direction, and the milling cutter A cuts the steel pipe B to the maximum allowable depth, and then feeds the cut. At the same time, relative rotation is applied between the milling cutter A and the steel pipe B to be cut, and the steel pipe B to be cut is progressively cut in a pseudo-spiral shape. When the pipe wall is partially cut, stop feeding the milling cutter A, and use the relative rotation between the rotating milling cutter A and the steel pipe B to completely cut the steel pipe to be cut. It is called cutting.

From FIG. 5 onwards, an apparatus for carrying out the method of the present invention, in which three milling cutters A are used, will be described below. Reference numeral 1 denotes a main body frame, and a rotary drum 2 is rotatably installed inside the frame while being guided by two types of guide rollers 3 and 4.
The rotating drum 2 is driven by a drive motor 5 via a reduction gear 6, a pinion 7, and an annular gear 8.

Three sets of milling heads 9 are installed in the rotating drum 2. A milling cutter A is attached to the milling head 9, and the cutter drive motor 1
0 allows high speed rotation via the gear box 11. 12 is a cutting feed mechanism, and 13 is its drive motor. This rotation is caused by the motor 13 through the reducer 14 → feed screw rod 15 → feed nut 16.
By moving the milling head 9 up and down as shown by the arrow (FIG. 7), it is possible to feed the milling cutter A a predetermined amount of cutting toward the center of the pipe.

In operation, 1. First, the steel pipe B is clamped (the clamping device is not shown), and the three milling cutters A are rotated at high speed in the direction of the arrow X from the husband's cutter drive motor 10 via the gear box 11. .

2 Three milling heads 9 and cutters A at the same time
is sent toward the center of the steel pipe B by driving the drive motor 14 of the cutting feed mechanism, and the milling cutter A makes a cut from the outer periphery of the steel pipe B by the maximum allowable depth L of the milling cutter A.

3 Next, when the rotary drum 2 is rotated in the direction of arrow Z by the drive motor 5 while giving cutting feed to the milling cutter A, the combination of the rotation of the milling cutter A, the cutting feed, and the rotation of the rotating drum 2 is achieved. As a result of the operation, the wall thickness of the steel pipe B is cut in the shape of three pseudo spirals, and by continuing this operation, when a part of the wall of the steel pipe B is cut off, the feeding of the milling cutter is stopped.

4 Rotate the rotary drum 2 while rotating the milling cutter to completely cut the steel pipe to be cut. In this embodiment, the steel pipe is clamped and the milling cutter A rotates around the steel pipe A, but in contrast, the milling cutter A is attached to the main body frame 1.
Of course, it is also possible to attach the steel pipe clamping mechanism directly to the rotary drum and rotate the steel pipe while clamping it. In short, as long as the steel pipe and the cutter can be rotated relative to each other, either can be rotated.

A plurality of milling cutters can be used, such as one or more, two or three.

The above is a method for cutting steel pipes, but the cutting of solid round steel differs from the method for cutting steel pipes in the following points. In other words, the solid round steel is first cut to the maximum depth allowed by the milling cutter, and then relative rotation is applied between the milling cutter and the solid round steel to be cut while applying cutting feed. After cutting the solid round steel in a pseudo-spiral shape, the feed of the milling cutter is stopped and relative rotation is applied between the rotating milling cutter and the solid round steel to be cut to cut the outer periphery of the solid round steel. The core is cut off once, and then the relative rotation between the milling cutter and the solid round steel is stopped, and a cut is made in the milling cutter to cut through the core.

The method of the present invention is as described above, and has the following effects.

Cut the milling cutter to the maximum allowable depth of cut, then feed the milling cutter and apply relative rotation between the cutter and the steel pipe to cut the steel pipe in a pseudo-spiral shape to cut the pipe wall. Then, the cutter feed is stopped and the steel pipe is completely cut by the relative rotation between the cutter and the steel pipe, so it is possible to efficiently cut a wide variety of steel pipes with different pipe diameters and wall thicknesses using the same milling cutter. Ta.

Although solid round steel does not have a hollow part, it is first cut in the same way as a steel pipe, and once it approaches the core, the feed of the cutter is stopped and the outer circumference of the solid round steel is cut, and then the cutting depth of the cutter is cut. Since the core portion is cut by feeding, it is possible to cut solid round steel extremely efficiently.

[Brief explanation of the drawing]

1 to 3 are explanatory diagrams of a known steel pipe cutting method. FIG. 4 is a diagram showing the principle of the present invention. 5 to 7 show examples of an apparatus for carrying out the method of the present invention, with FIG. 5 showing a front view, FIG. 6 a side view, and FIG. 7 showing a cutting feed mechanism. In the diagram; A... milling cutter, B...
Steel pipe to be cut, C, D...Cutting trajectory by milling cutter, 1...Main body, 2...Rotating drum, 3,
4... Guide roller, 5... Drive motor, 6...
Reducer, 7... Pinion, 8... Annular gear, 9...
... Milling head, 10 ... Drive motor, 11
... Gear box, 12 ... Cut feed mechanism, 13 ...
Drive motor, 14...Reducer, 15...Feed screw rod.

Claims (1)

[Scope of Claims] 1. A cutting device that has a milling cutter that can feed a cut toward the center of a steel pipe to be cut, and the steel pipe to be cut and the milling cutter are rotatable relative to each other. As it rotates, the milling cutter makes a cut to the maximum allowable depth of cut, and then, while giving cutting feed to the milling cutter, relative rotation is applied between the milling cutter and the steel pipe to be cut, so that the steel pipe to be cut is turned into a pseudo spiral. Once the pipe wall has been cut, the feed of the milling cutter is stopped and relative rotation is applied between the rotating milling cutter and the steel pipe to be cut to completely cut the steel pipe to be cut. A method for cutting steel pipes, characterized by: 2. A cutting device that has a milling cutter that can feed a cut toward the center of a solid round steel to be cut, and the solid round steel to be cut and the milling cutter are rotatable relative to each other. As it rotates, the milling cutter makes a cut to the maximum allowable depth of cut, and then, while giving cutting feed to the milling cutter, relative rotation is given between the milling cutter and the solid round steel to be cut while the milling cutter is being cut. The solid round steel is cut in a pseudo-spiral shape, and then the feed of the milling cutter is stopped, and relative rotation is applied between the rotating milling cutter and the solid round steel to be cut. The outer circumference of the steel is cut, then the relative rotation between the milling cutter and the solid round steel to be cut is stopped, and cutting feed is applied to the rotating milling cutter to poke the core of the solid round steel to be cut. A method for cutting solid round steel, which is characterized by cutting.