JPS60130422A - Steel pipe correcting machine - Google Patents

Abstract

PURPOSE:To enhance efficiently the out of roundness of a pipe by enabling an upper die of columnar body, whose outer circumference of cross section consists of the combination of a circular arcs and straight lines to move independently in the horizontal and vertical directions while maintaining the relation parallel in three dimensions to the axis of a lower roll. CONSTITUTION:Two lower rolls 12, 13 attached parallelly to a base body are rotated in the same direction and at the same speed by driving a motor. A steel pipe 14 is rotated by rotating the lower rolls 12, 13 to set the center line of its insufficient bending part 141 at the position approximately equivalent to the center between the lower rolls 12, 13. Next, an upper die 11 is brought into contact with the center line of the insufficient bending part 141 of a steel plate to press it by lowering the die 11. The curvature of the central part of part 141 is then corrected by providing a rolling down force to it with the aid of a hydraulic cylinder.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a straightening machine for steel pipes formed by a bending roll machine or the like, particularly for large-diameter steel pipes.

Traditionally, bending roll machines have been the most popular method for forming large-diameter steel pipes with a circular cross section by pressing a flat plate, and are versatile because steel pipes of different diameters can be manufactured relatively efficiently using one machine. It has been highly evaluated and various types have been developed and put into practical use. However, any of the various types of machines, which can be roughly divided into pyramid-shaped or pinch-shaped parts, can bend a flat plate by pinching it between upper rolls and lower rolls whose diameter is smaller than the diameter of the target steel pipe. The essence of processing remains the same.

Therefore, even with various know-how and control means for pressing operations, it is extremely difficult for a formed steel pipe to have an even, perfect circle in any cross section. In other words, when inspecting an arbitrary cross section, a certain part of the cross section that should be a perfect circle has a large curvature due to insufficient bending and retreats inward from the correct arc, and a certain part has a small curvature due to excessive bending and moves outward from the correct arc. If you draw an imaginary line that bulges out and is a perfect circle, it will end up being composed of asymmetrical curves that go in and out of the line. This is an essential problem due to the mechanism of the bending roll machine, which is suitable for high-mix, low-volume production.

For this reason, the manufacturer must take various corrective measures based on the specifications imposed on the product (steel pipe) in order to expand or contract the portion that is perpendicular to the roundness within the permissible range.

One method for this purpose is to expand the area where the arc has become smaller by heating it with a gas flame or the like from the outside of the steel pipe. However, this method requires considerable skill because it deforms only a limited area while delicately changing the balance between heating and cooling, and it also tends to shrink the entire tube. The problem remains.

Furthermore, as an on-site method, it is often seen that the steel pipe is hoisted horizontally using a hoist, the lifting device is removed, and the pipe is dropped horizontally to the ground, and the mechanical impact force is used to correct the problem. However, it is natural that this also cannot be used to make slight corrections. In addition, if only the pipe end of the steel pipe requires roundness in relation to the mating member, only the pipe end is held between the upper and lower molds and corrected using hydraulic pressure, so that each part of the circumference is successively corrected. A simple straightening machine that alternately repeats the transfer and pressing of steel pipes is already in use.

However, the straightening machine described above is not suitable for large-diameter steel pipes manufactured as tube bodies for heat exchangers such as boilers, which require high roundness over the entire length because tube sheets are attached to several locations on the tube body. .

In addition, methods have been put into practical use in which the pipe is formed by reducing its inner diameter slightly from the desired one, and then the entire pipe is expanded by applying water pressure, but this method is only economical in the case of mass production of a small number of products using huge equipment. This is a method that satisfies the following.

On the other hand, there is also a means of straightening using a hending roll machine. This is a bending roll machine consisting of one upper roll and two lower rolls. For models that can move horizontally, this method is conveniently used at work sites.

To explain this method with reference to Fig. 1, the over-bent portion of the formed steel pipe (4) with a small curvature (the shaded area in the figure) is placed on one of the lower rolls (2) and (3). The upper roll (1) is then moved horizontally and vertically to a position where the spacer (5) made of a steel piece is sandwiched between the spacer (5) and the steel pipe (4). When the upper roll is pushed down in this state, the pressing force is applied to the spacer (5)
It is transmitted to the over-bent part through both ends of the pipe, enlarges the small arc part, and corrects the steel pipe as a whole to the correct arc. However, when this method is adopted, the part of the steel pipe (4) that requires correction is a curved surface over a certain range, and the parts of the spacer (5) that contact the steel pipe must be moved one after another to undergo correction. It is necessary to rotate the steel pipe (4) little by little. At that time, this rotation causes the spacer (5) to be released from the clamped state, so the spacer (5) must be clamped again to the position corresponding to FIG. 1.

In addition, the range of underbending and the degree of underbending vary depending on the state of the previous process, and the straightening range is wide and narrow, with partial overbending and underbending scattered randomly in one steel pipe. For the width (B) of the spacer (5)
It is necessary to prepare several types of different types of pipes in advance and replace them each time, and apart from straightening near the pipe ends, straightening near the center of a long pipe is extremely difficult, and operational safety cannot be guaranteed. The problem is that it is difficult.

This invention solves the above problems and, when a long steel pipe is irregularly scattered with partial insufficient bending or overbending, it can be corrected efficiently and safely with simple work. The purpose is to provide a straightening machine that improves roundness.

In order to achieve this object, the steel pipe straightening machine according to the present invention has a columnar body whose cross-sectional outer periphery is a combination of circular arcs and straight lines. The mold is arranged parallel to the axis of the lower roll, and the upper core mold is independently rotatable, and horizontal movement and vertical movement are independent of each other while maintaining a three-dimensional parallel relationship to the axis of the lower roll. The feature is that it is possible to

Since the present invention has the above-described configuration, it can achieve the following effects.

FIG. 2 is a conceptual front view illustrating the effect of correcting the insufficiently bent portion of a steel pipe according to the present invention.

Two lower rolls (12) and (13) attached to the base in parallel are rotated at a constant speed in the same direction by a drive motor. In Fig. 2A, the processed steel pipe (14) is placed across the lower rolls (12) and (13), and the steel pipe (14) is rotated by the rotation of the lower roll to achieve the desired insufficient bending part (141). The first stage is shown in which the center line of the roll corresponds to approximately the center between the lower rolls (12) and (13). In the figure, (11) is an upper mold disposed above two lower rolls in parallel with the axis of the lower rolls, with a flat part (111) whose cross section is a straight line and a curved part whose cross section is an arc. Part (1
12) It is a columnar body that forms an outer peripheral outline by a combination of. In the case of the figure, as an example, a polyhedral columnar body is shown, which is a cylinder cut by plane parts (Fl, F2.F3.F4) with different widths on four sides, but the combination of these planes and curved surfaces is difficult to correct. It can be selected arbitrarily depending on the shape and dimensions of the steel pipe, the accuracy of the previous process (bending), the accuracy of specifications, etc.

Figure 2B shows that in the second stage of the work, the upper mold (11) is moved downward by an independent mechanism, and the insufficient bending part (14) of the steel plate is moved downward.
1) shows the state of contacting and pressing the center line. The upper mold abuts approximately the center line of any of the curved surface portions (112). The push-down mechanism attached to the upper die (11) in this state,
For example, by applying a reduction blade using a hydraulic cylinder, the curvature of the central portion of the insufficiently bent portion (141) of the steel pipe is corrected. In actual work, even if the center part of (141) is corrected in one straightening operation, there will be small areas of insufficient bending (141) at both ends.
11) (1412) may remain, so if it exceeds the specification tolerance, lift the upper mold (]1) to release the pressing force and rotate the lower rolls (12) and (13) to bend it. Center the missing part (1411) or (1412) in Figure 2A
By changing the position to correspond to (141) and repeating the rolling process again, it is possible to gradually obtain accurate roundness.

FIG. 3 shows that the present invention can be applied to an over-bent portion (14) of a steel pipe (14).
FIG. 2 is a front conceptual diagram illustrating the action of correcting 2). First, in FIG. 3A, the rotation of the two lower rolls (12) and (13) brings the center line of the over-bent portion (142) of the steel pipe (14) into contact with, for example, one of the lower rollers (12). 2 shows the state in which the steel pipe (14) is rotated. As shown in the figure, the abutting position is determined so that the center line of the over-bent portion (142) coincides with the line connecting the center point (axis) of the steel pipe (14) and the center point (axis) of the lower roller.

FIG. 3B shows that the upper mold (11) is moved horizontally by X and vertically by Y from the state of FIG. 3A, and the over-bend portion (142 )
This shows the state in which they are in contact with each other so as to sandwich the center of the two. The part that the upper mold comes into contact with is different from that shown in FIG. 2, and is a part of the flat part (111) of the upper mold (11) that has an appropriate width, for example, the flat part (Fl). Which plane portion (Fl to F4) to select can be determined by the width of the over-bent portion (142). In the state shown in Figure 3B, the center of the steel pipe (14) (
C1) - Center of the upper die (11) (C2) - Center of the flat part (111") of the upper die (11) (C3) -> Center of the excessively bent part (142) of the steel pipe (14) (C4) - Bottom Roll (12
) are all located on one straight line. In this state, the upper mold (11) is pressed by, for example, a hydraulic cylinder, so that the excessively bent portion (14) is
2) has its curvature corrected from its center and approaches a perfect circle. If one-time straightening is insufficient, the steel pipe (14) is relocated and finely adjusted in the same manner as in the case of insufficient bending in Fig. 2, and the work is repeated until a high degree of roundness is obtained.

Next, embodiments of the present invention will be described based on the drawings.

FIG. 4 is a front view of the embodiment, and FIG. 5 is a side view. Two lower rolls (12) and (
13) are rotatably installed in parallel, and (16)
is the lower roll bearing that supports both rolls, and the gear (17
), deceleration tJll (1B>), the two lower rolls (1
2) and (13) rotate.

Gate frames (20) and (21) are erected at both left and right ends of the base (15), straddling the lower roll bearing (16), and these gate frames (20) and (21) are operated by hydraulic pressure for lifting and lowering, respectively. The cylinder (22) is sandwiched between the lift hydraulic cylinders (22).
) is installed in the gate form (
20), the upper mold bearing (24) which pivotally supports the upper mold (11) is freely raised and lowered along the guide groove recessed vertically in (21). The upper mold (24) rotatably supports the upper mold (11) O, and the electric mold drive ill (25) transmits rotational force independent of the lower roll. Since this electric motor must stand still at a desired point and press the steel pipe (14), it is desirable that the electric motor be equipped with a brake.

Legs (201>, (211) of gate frames (20), (21)
) is penetrated by a horizontal movement axis (26), and this axis is connected to the base (15).
) The gate frame and the base are connected by passing through the flanges (151) projecting on both sides of the gate frame.

A keyway (
261) and a corresponding angular projection (152)
is provided protrudingly from the flange portion (151) of the base.

By fitting this key groove (261> and the angular projection (152), the base (15) and the gate frame (20), (21
) are connected so that they can slide left and right. A male threaded portion (262) is formed in the center of the horizontal movement shaft (26), and this engages with a female thread threaded on the inner diameter of the boss hole of the ohmic foil (27).

The worm wheel (27) is screwed into the worm gear (2B).
), the electric motor for left and right movement (
30) receives the transmission of rotational force. In other words, 1. The gate frames (20) and (21) sandwiching the upper mold (11) slide left and right independently with respect to the base (15), and the lower roll (
12) and (13) can be changed to occupy a desired location.

In addition, a tilting hydraulic cylinder device (31) that tilts one gate frame (20) when loading or unloading the steel pipe (14) between the upper die and the lower roll. '1F type restraining device (32
) and other auxiliary equipment must also be provided.

Since the present invention has the above-described configuration and operation, it is possible to most efficiently correct under-bent parts or over-bend parts that are irregularly scattered at various places in a single bent steel pipe using a single straightening machine, thereby making it perfectly round. You can get the effect of increasing the degree. Moreover, it is not only efficient but also has a wide range of versatility, so by researching the combination of straight lines and bends in the cross section of the upper mold (11), it is possible to make the most suitable for both mass-produced products and single products. Able to plan compliant work standards.

In addition, according to this invention, it is possible to straighten not only the ends of steel pipes, but also the center of long objects with the highest degree of safety, and the work environment is better than any conventional straightening methods such as gas heating, dropping, and hammering. It also has unique effects, such as being superior in water and being immune to pollution sources.

[Brief explanation of drawings]

FIG. 1 is a front sectional view showing an example of a conventional correction means, FIGS. 2A, B and 3 A, B are front sectional views explaining the present invention in detail, and FIG. A front view showing an example, and FIG. 5 is a side view thereof. 111... Upper roll, (2), (3)... Lower roll, (4)... In 'IF, (5)... Spacer (11)... Upper mold, (111)... ...Flat part of the upper die, (112)...Curved surface part of the upper die, (12), (13)...Lower roll, (14)...Steel pipe, (141), (1411), ( 1412) ... Insufficient bending part of the steel pipe, (142) ... Overbending part of the steel pipe, (15)...
・Base, (151)...Base flange, 3 (152)...Square projection, (16)...Lower roll bearing, (17)...Gear, (18)...Reduction Machine, (
19)...lower roll drive motor, (20), (21)...gate frame, (201), (211)...legs of portal frame, (22)
...Elevating hydraulic cylinder, (23)...Hydraulic unit, (24)...Upper die bearing, (25)...Upper die drive motor, (26)...Horizontal movement axis, (261 )...Horizontal movement axis keyway, (262)...
- Male screw part of horizontal movement shaft, (27)...Worm wheel, (28)...Worm gear, (29)...Horizontal drive shaft, (30)...Left and right movement electric motor, (31) ... Hydraulic cylinder device for tilting, (32)
...Upper type restraint device. Applicant Kurimoto Iron Works Co., Ltd. Agent Patent Attorney Junzo Aono 4

Claims (1)

[Claims] Above two lower rolls that are rotatably attached to a base in parallel, a columnar upper mold whose cross-sectional outer periphery is a combination of circular arcs and straight lines is arranged parallel to the axis of the lower rolls. A steel pipe straightening machine characterized in that the upper mold is independently rotatable and can independently move horizontally and vertically while maintaining a three-dimensional parallel relationship with the axis of the lower roll.