JPH0377724A - Lower roll for forming band plate edge part of welded steel pipe - Google Patents

Abstract

PURPOSE:To eliminate the troublesome for exchanging the lower roll and to reduce the number of rolls by roundly providing the concave shaped curved surface which has each different radius of curvature according to the pipe size to be worked at every stage part of respective different outside diameters of the lower roll for forming the band plate edge part which is a pair of left and right and is separated. CONSTITUTION:The lower rolls 1, 1 bisected into the left and right are inserted on the outer periphery of the roll shaft 2 so as that the space of both rolls is adjustable. The left and right divided lower rolls 1, 1 consist of plural rolls with step which are composed of a small outside diameter in the inner side and a large outside diameter in the outer side between the both rolls e.g. the three stage rolls of small, middle and large. The concave shaped curved surfaces 3, 4, 5 of respective different radii of curvature R1, R2, R3 are roundly provided at the respective stages of different diameter. The both left and right side parts of band plate 8 is held between the divided lower rolls 1, 1 and the upper rolls 9, 9 which is set to its upper side, and the plate 8 is fed to the welding machine side and so the band plate side edge 8a is formed to curved shape. Therefore, the plural band plate edge part forming of the different pipe size to be worked is executed with one set of the lower rolls.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a lower roll for forming the edge of a strip of welded steel pipe.

``Prior art J'' For example, as in the case of JP-A No. 58-167025, there is a lower roll having a small outer diameter at the middle part and a large outer diameter at both left and right ends, and JP-A No. 57-209722. As in the case of , a lower roll is known in which the lower roll is divided into left and right halves to form a pair of left and right rolls.

``Problems to be Solved by the Invention'' Rolls for forming the edge of a welded steel pipe strip can create a curved portion on the edge of the strip according to the size of the pipe by sandwiching the strip between the upper and lower rolls and passing it through. Because of this, it is necessary to replace the rolls each time the pipe size changes. This requires a large amount of effort to replace the rolls, and the number of rolls required corresponds to the number of pipe sizes.

The present invention particularly relates to improvement of the lower roll among the above-mentioned upper and lower rolls. This makes it possible to reduce the number of lower rolls, thereby reducing the trouble of exchanging the lower rolls and reducing the number of lower rolls.

"Means for solving ria" The lower roll for band plate edge acid forming is formed by a pair of left and right split rolls, and both of these split rolls are separated so that the inner side between the front rolls has a small outer diameter and the outer side has a small outer diameter. A plurality of stepped rolls having a large outer diameter were used, and a concave curved surface with a different radius of curvature was provided around each step of the rolls having different outer diameters depending on the pipe forming size.

“Example” First, the first example shown in FIG. 1 will be explained.
Reference numeral 1 denotes a lower roll divided into left and right halves, and these divided lower rolls are fitted onto the outer surface of a roll shaft 2 so that adjustment between the two rolls is possible. The left and right divided lower rolls 1.1 are a plurality of stepped rolls with a small outer diameter on the inner side and a large outer diameter on the outer side between the two rolls, and in the illustrated example, there are small, medium, and large rolls. It is made into a three-tiered roll. Concave curved surfaces 3, 4.5 having different curvature radii R1, R2, R3 are provided around each step portion having different equal diameters. As shown in the figure, each concave curved surface has a concave curved surface 3 for small diameter size on the small outer diameter step, a concave curved surface 4 for medium diameter size on the small outer diameter step, and a concave curved surface 4 for medium diameter size on the large outer diameter step. It is preferable to form concave curved surfaces 5 for each purpose,
A flat portion 6- of an appropriate length is attached to each inner side portion of each concave curved surface. It is preferable to add a radius to the joints 7 between each step to prevent roll damage.

Reference numeral 8 denotes a strip plate, whose left and right sides are held between the lower divided roll 1.1 and the upper roll 9.9 provided above it, and as it advances toward the welding machine, the side edge 8a of the strip plate is formed. is formed into a curve.

The roll diameter of each stage of the concave curved surface 3.4.5 is different. For this reason, no matter which concave curved surface is used, the height of the roll must be adjusted so that each flat part 6 has a constant pass line height, and when driving the lower roll, the peripheral speed of the roll must be kept constant. Use a continuously variable transmission, etc. to maintain

In the illustrated example, the left and right edges of the band plate are curved by the concave curved surfaces 4.4 for medium diameter sizes, but when both edges of the band plate for small diameter pipe forming are curved, the concave curved surfaces 3 for small diameter sizes are used. .3
In addition, when both edges of the band plate for forming large diameter tubes are curved, the concave curved surfaces 5.5 for large diameter sizes are formed. Incidentally, the interval between the left and right divided rolls 11 is adjusted to a predetermined width according to the width of the band plate 7.

The second embodiment shown in FIG. 2 consists of divided rolls 1. Divided roll 1 shows an example where 1 is a stepped roll of two sizes, large and small.
．． A spacer IO is fitted into the roll shaft 2 portion between the roll shafts 1 and 1.

"Effects of the Invention" The present invention is as described above, and consists of a pair of left and right divided lower rolls 1.1, which are divided into a plurality of stages having a small outer diameter on the inner side between the two rolls and a large outer diameter on the outer side. A concave curved surface with a different radius of curvature according to the size of the tube is provided around each step where the outer diameter of the two rolls differs, so it is possible to manufacture multiple pieces using the same divided lower roll. The edge of the tube-sized strip can be curved, which saves the trouble of re-arranging the rolls.The number of rolls can also be far smaller than in the past, and the storage space for the rolls can also be reduced. In this way it is possible to significantly reduce the molding costs of the strip edges.

[Brief explanation of drawings]

11th! 1 is a front view showing a first embodiment of the lower roll of the present invention, and FIG. 2 is a sectional view showing the second embodiment. l...Divided lower roll 2...Roll axis 3.4.5...Concave curved surface

Claims (1)

[Claims] The lower roll for forming the edge of the strip is formed by a pair of left and right split rolls, and these split rolls are separated by a plurality of steps with a small outer diameter on the inner side and a large outer diameter on the outer side between the two rolls. A strip edge of a welded steel pipe characterized by having a concave curved surface having a different radius of curvature depending on the pipe manufacturing size at each step where the outer diameter of both rolls is different. Lower roll for forming.