JPS5913288B2 - Tube roll forming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a roll-forming method for tubes, and more particularly to a roll-forming method for producing cylindrical tubes from sheet metal.

For example, in manufacturing an electric resistance welded tube, a metal plate is formed into a cylindrical shape using a forming roll, and then the abutting portions in the longitudinal direction of the tube are welded to obtain the tube.

However, as a conventional roll forming method, the methods shown in FIGS. 1 to 3 are widely adopted. That is, in the rough forming process shown in Fig. 1, a metal plate is passed through a hole formed by horizontal upper and lower rolls each having a convex curved surface and a concave curved surface, and the metal plate is formed into a U-shape while being restrained by the upper and lower rolls. do. Next, in the intermediate forming step shown in FIG. 2, a pair of vertical rolls having a concave curved surface designed to contact the entire outer surface of the metal plate 15 formed into a U-shape is used to form a circular shape in several stages. It is molded into. Furthermore, in the final forming process, as shown in Figure 3, a pair of fin rolls designed to contact almost the entire outer surface of the circular raw tube while restraining the ends of the circular raw tube are used in several stages. Molding is performed while applying compression in the width direction. However, the conventional roll forming method described above has the following problems.

25(1) The range of roll sizes that can be used is extremely narrow, and each roll is required to match the diameter of pipe production.As a result, a large number of rolls must be prepared, which increases roll cost.

(2) Time and effort required for changing rolls due to changes in pipe diameter30
It takes a lot of time, the utilization rate is poor and productivity is extremely low.

(3) Since the roll and the metal plate are in full contact with each other throughout the forming process, slipping occurs due to the difference in peripheral speed between the roll and the metal plate, resulting in large energy loss during forming, and scratches, etc. Occurrence can be seen. 35 The present invention improves the above-mentioned problems of the prior art, can support the manufacture of cylindrical tubes of various sizes with a small number of rolls, greatly reduces the degree of friction between the material to be formed and the rolls, and improves productivity. The purpose of the present invention is to provide a pipe roll forming method that can dramatically improve the performance of pipe roll forming.

To achieve these objectives, the roll forming method of the present invention is capable of symmetrically displacing any specific diameter in a plane perpendicular to the tube axis direction when forming a plate-like body to produce a cylindrical tube. A pair of rolls that can be fixed, and between the pair of rolls,
one or more bending rolls having rotational axes perpendicular to the rotational axes of the pair of rolls, which are displaceable in a direction perpendicular to the rotational axis direction in a plane perpendicular to the rotational axis direction and/or the tube axis direction; The present invention is characterized in that a cylindrical tube is manufactured by forming a forming pass and passing a plate-like member through one or more of the forming passes. The details of the roll forming method of the present invention will be explained below.

When manufacturing a cylindrical tube according to the present invention, a metal plate-like body, such as a metal strip (steel strip), cut plate, etc., is used as the material.
These raw materials are not supplied as they are to the molding pass of the present invention, but are usually supplied to the molding pass of the present invention using a push roll device, which will be described later. That is,
During roll forming, a push roll device is driven to forcibly move the material, and its tip is pushed into a forming path formed by non-driven forming rolls. As the pushing roll device, flat upper and lower rolls as shown in Fig. 5 may be used, or upper and lower rolls having uneven surfaces of a single curvature as shown in Fig. 6 may be used to perform the pushing. Initial molding may also be performed at the same time.

Furthermore, as shown in FIG. 7, pressing and forming may be performed using upper and lower rolls having a flat central portion and curved ends. Which of the push rolls to adopt from these Figures 5 to 7 can be selected appropriately by considering the thickness, width, material, etc. of the material to be formed. It is desirable to use the one shown in FIG. 6 or 7, which has a pressing and forming function. In the present invention, a plate-shaped body charged by such a push roll device is passed through a forming path constituted by unique forming rolls to be formed into a desired cylindrical tube.

A specific example of this forming roll is shown in FIG. FIG. 8a shows a pair of upright truncated conical vertical rolls 5 and the pair of vertical rolls 5.
An example of a forming pass consisting of one bent ronol 6 located in between is shown.

The rotation axis of the vertical roll 5 is perpendicular to the tube axis direction,
Furthermore, the pair of vertical rolls 5 are movable vertically and horizontally as shown by arrows, and can be fixed at a predetermined position. Making the vertical roll 5 freely displaceable means that it is symmetrically displaced with respect to an arbitrary specific diameter in a plane perpendicular to the tube axis direction, and when the plate-shaped body 1 is formed into a cylindrical tube. The interval between the pair of vertical rolls 5 can be defined according to the diameter, or when molding is performed in multiple molding passes, the interval and height position of the pair of vertical rolls 5 can be arbitrarily determined according to the order of the molding passes. It is to be adjusted to. Furthermore, the bending rolls 6 are the pair of vertical rolls 5.
The vertical roll 5 has a rotation axis that is freely displaceable in a direction perpendicular to the rotation axis in a plane perpendicular to the rotation axis direction and/or the tube axis direction and perpendicular to the rotation axis of the vertical roll 5. Further, the bending roll 6 is disposed at the center between the vertical rolls 5, and presses the central part of the plate-like body 1 to bend the plate-like body 1 by the vertical rolls 5.
This contributes to the bending of the plate-shaped body 1 together with the regulation of both ends of the plate-shaped body 1, and also helps to stabilize the pass line. To explain this stabilization of the pass line in a little more detail, as mentioned above, by configuring the bending roll, that is, the presser roll, to be freely displaceable in a plane perpendicular to the tube axis direction, it is possible to stabilize the pass line in the material width direction. By making the locus lengths of each point in the tube axis direction as equal as possible, it is possible to stably construct a path line that does not cause edge stretching or edge backling.

FIG. 8b shows a point where the bending rolls 6 are combined into a pair, and the bending rolls 6 shown in FIG.
Although different from the above, in this forming pass, the pair of bending rolls 6 are made vertically and horizontally movable like the vertical rolls 5, so that the mutual spacing between the bending rolls 6 can be changed arbitrarily.

Therefore, a strong bending action can be applied to the vicinity of the edge of a thick plate, where it is difficult to apply the desired bending action using only one bending roll 6, and this is extremely effective in manufacturing cylindrical tubes. In the case of Fig. 8c, there is only one bending roll 6, but its body length is made relatively long, and its R portions at both ends press the edge portion of the plate-like body 1, and it is almost the same as Fig. 8b. The aim is to obtain the effect of

8A, b, and c above all show forms of forming rolls suitable for the first stage of the forming pass in which the plate-like body 1 has a small curvature, and the vertical roll 5 has an upright conical shape, and the bending roll 6 has a plate shape. A state in which the shaped body 1 is charged and contacted from above is shown. On the other hand, the 8th
Figures D and e show the form of the forming roll used in the later stage of the forming pass, where the forming has further progressed and the curvature has increased. Figure 8d
is a forming path consisting of a pair of vertical rolls 5 in the shape of an inverted cone, and a bending roll (presser roll) 6 that contacts the plate-like body 1 formed into a substantially cylindrical shape from below.

The pair of vertical rolls 5 have rotational axes perpendicular to the tube axis direction, similar to the vertical rolls shown in FIGS. 8A, b, and c, and are symmetrically displaced with respect to any specific diameter in a plane perpendicular to the tube axis direction. It has become freely possible. The presser roll 6 mainly has the function of supporting the plate-shaped body 1, and an ordinary flat horizontal roll is sufficient. Fig. 8e is composed of a vertical roll 5 similar to that shown in d and a pair of presser rolls 6, and by forming the presser rolls 6 into a pair in this way, the support of the plate-shaped body 1 is further stabilized. be able to.

Of course, the presser roll 6 is also configured to adjust its position in the vertical and horizontal directions in response to changes in pipe size. In order to minimize the friction between the roll and the plate, the shape of the forming roll consisting of the vertical roll and the bending roll (presser roll) should be designed so that the plate and the roll come into contact at almost one point. preferable.

It is also desirable to change the roll surface inclination of the conical vertical roll depending on the stage of the forming pass so that the roll surface always coincides with the tangential direction at the point of contact between the roll and the plate-shaped body.
This allows good bending pressure to be applied to the plate-like body. Furthermore, the roll displacement mechanism includes vertical movement and horizontal movement (
Any system may be used as long as it has a mechanism that allows the opening and closing movement of a pair of rolls, but it can quickly respond to changes in the molded shape and size of the plate-shaped object, and can be fixed at any position. Preferably something wet. Next, FIG. 4 shows a forming apparatus array for carrying out the roll forming method of the present invention, which is constructed using the above-described forming rolls.

In FIG. 4, 1 is a metal plate-shaped body that is the raw material for a cylindrical pipe, and is a steel strip having a width necessary for the diameter of the pipe, and 2 is the plate-shaped body 1.
This is a 1-drive push roll that allows the tip of the roll to run to the finish-forming stand, the fin pass roll.

Reference numeral 3 denotes a forming roll composed of, for example, 4 stands, and this forming roll 3 is formed by the forming path shown in FIG.
, b or c, and the black 3 and wash 4 stands are constructed using the molding passes shown in t or e of FIG. 8.

Reference numeral 4 denotes a fin pass roll for final forming the cylindrical tube formed by the forming roll 3, and has the same roll shape and drive device as conventionally known rolls.

When manufacturing a cylindrical tube according to the present invention, generally after the tip of the material is pushed into the fine pass roll, the pushing roll is allowed to move freely by leaving a sufficient gap between the upper and lower rolls, and thereafter the material is moved only by the fine pass roll. It is desirable to run the material and finish forming it to prevent asymmetrical forming and twisting of the material.

The positions of the rolls and the state of contact between the plate and the rolls when manufacturing cylindrical pipes of different diameters using the above-described forming path of the present invention are shown in FIGS. 9A to 9E. In the figure, the left half shows the case in which the largest size pipe is made from a plate-like material, and the right half shows the case in which the smallest-sized pipe is made from a plate-like material. The forming rolls C, 2, d, and 8e are respectively shown as the forming roll shown in FIG. 8a, 2, and 8e. As is clear from the figure, the shape of the forming roll used in the present invention does not need to be changed depending on the diameter of the pipe being made; the forming roll can simply be displaced according to the size and held at a predetermined position and height. This makes it possible to perform rough forming and intermediate forming of different pipe diameters using the same roll. As a result of carrying out the roll forming method according to the present invention, according to the experiment of the present inventor, 8 dia.φ to 1♂φ.
The number of rolls on hand for rough forming and intermediate forming was several dozen in the conventional method for various pipe forming diameters, but this can be reduced to four in the present invention.

Additionally, the time required to change the pipe diameter was reduced by more than % compared to the conventional method. There was no problem with the roundness, bending, etc. of the obtained tube. It should be noted that the roll forming method of the present invention can of course be applied to the production of electric resistance welded pipes, but it can also be applied not only to cylindrical pipes but also to the former forming part of square pipes, the forming of gutter-like pipes, etc. .

The effects obtained by the roll forming method of the present invention are as follows.

(1) The number of rolls can be significantly reduced compared to conventional molding methods.

(2) Changes in the pipe diameter can be handled by simply moving the forming rolls, and there is no need to replace the rolls as in the past.

Therefore, the operating rate of the molding machine can be significantly improved. (3) Friction between the plate and the roll can be reduced.

(4) Since the roll has a simple shape, it is easy to manufacture.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a rough forming roll in a conventional method, Fig. 2 is a sectional view of an intermediate forming roll in a conventional method, Fig. 3 is a sectional view of a final forming roll in a conventional method, and Fig. 4 is a sectional view of a roll for final forming in a conventional method. A side view showing an example of a molding device array for carrying out the process,
5, 6, and 7 are cross-sectional views showing each example of the push roll device, FIG. . 1... Plate-shaped body, 2... Push roll, 3
... Forming roll, 4 ... Fine pass roll, 5 ... Vertical roll, 6 ... Bending roll.

Claims (1)

[Claims] 1. When manufacturing a cylindrical tube by forming a plate-shaped body, a pair of truncated conical or inverted truncated conical rolls that can be symmetrically displaced and fixed with respect to an arbitrary diameter in a plane perpendicular to the tube axis direction. , between the pair of truncated conical or inverted truncated conical rolls, the pair of truncated cones can be freely displaced in a direction perpendicular to the rotational axis in a plane perpendicular to the rotational axis direction and/or the tube axis direction. Alternatively, a forming path is formed by one or more presser rolls having a rotation axis perpendicular to the rotation axis of the inverted truncated conical roll;
A method for roll forming a tube, characterized in that a cylindrical tube is manufactured by passing a plate-like object through one or more of the forming passes.