JPH06179017A - Straightening roll set and straightening machine for steel tube etc., wherein it is used - Google Patents

Abstract

PURPOSE:To provide a straightening roll set and a straightening machine for a steel tube etc., which can improve the straightening accuracy of a tube end part and generates no scratch. CONSTITUTION:The machine consists of a large diameter, long, concaved surface-shaped and large roll 4 in which its roll shaft is arranged ob-liquely to the pass line L in the horizontal surface and three small diameter, short and concaved surface-shaped small rolls 1, 2, 3 which are inclined in the direction reverse to the roll shaft of the large roll 4 and are arranged along the pass line L. The steel tube P is arranged so that it is held between the small rolls 1, 3 at both ends and both end parts of the large roll 4 and between the small roll 2 in the middle and the middle part of the large roll 4 and the steel tube P is prevented from protruding to remove a guide causing a scratch.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a straightening roll set and a straightening machine for steel pipes using the straightening roll set. More specifically, the present invention relates to a straightening roll set and a straightening machine using the straightening roll set for straightening a bend generated during processing of a steel pipe or the like (the steel pipe and the like in the present specification include both a steel pipe and a round bar). . The straightening machine for steel pipes and the like is provided after the rolling equipment for steel pipes and the like, and straightens the bending of the steel pipes and the like sent from the rolling mill and sends them to the subsequent process,
It is required that the bend is corrected with high accuracy over the entire length of the steel pipe or the like so as not to hinder the subsequent process, and that the steel pipe or the like is not scratched to improve the quality.

[0002]

2. Description of the Related Art As a straightening machine for steel pipes that has been conventionally used, a 6-roll facing type shown in FIG.
There are a 7-roll facing type shown in (1) and an 8-roll facing type shown in (III) of the same figure. These have three or four pairs of straightening rolls r arranged above and below the pass line L, and a steel pipe or the like is passed between the rolls r to repeatedly bend and straighten the bend of the steel pipe or the like. It is a thing. In these straightening machines, the larger the number of rolls, the more the restraint force and bending number of the steel pipe are improved, and the straightening accuracy is increased.However, since the pipe end portion cannot be subjected to sufficient repeated bending,
There was a problem that the straightening accuracy of the pipe end was lowered.

Therefore, as a means for improving the straightening accuracy of the pipe end, a straightening machine described in JP-A-3-146612 (conventional example) and a straightening machine described in JP-B-60-33567 (conventional example).
Is proposed. The conventional example is of a type called a two-roll straightening machine. As shown in FIG. 6, a steel pipe P is passed between a pair of upper and lower rolls r1 and r2 and is bent as shown in FIG. 7 (I). I am trying to correct it. However,
In the conventional example of the two roll facing type, there is a problem that the escape of the steel pipe P occurs in the directions indicated by arrows a and b in FIG. 6 (II) and bending cannot be applied. This point will be described with reference to FIG. In the figure (II), δ is the amount of pushing down (bending amount) by the upper roll r1 at the roll ends (X position and Y position).
Then, the solid line circle between the upper and lower rolls r1 and r2 shows the position of the steel pipe P pushed down, and the dotted line circle shows the restored position of the steel pipe P when the bending force acting on the steel pipe P is released. When the pushing force is released from the steel pipe P that is pushed down and bent at the ends (X position and Z position) of the upper and lower rolls r1 and r2,
Since a force to return from the current position to the restoration position shown by the dotted circle is generated as shown by arrows a and b, this force is generated as shown in FIG.
The ejection force (arrows a and b) shown in I) is obtained. Therefore, in the conventional example, as shown in FIG. 6 (II), a guide G for preventing the steel pipe from jumping out is required. During straightening, the steel pipe P moves forward while rotating, and naturally comes into sliding contact with the guide G. Therefore, although the straightening accuracy is improved, a new problem arises that scratches occur.

The above-mentioned conventional example is a conventional 8-roll opposed type with a pipe end correcting function added, and as shown in FIG.
In the conventional 8-roll facing type, the inner two roll sets R2 and R3 are large rolls. In this conventional example, when the steel pipe P is passed through all of the four pairs of roll sets R1, R2, R3, R4, the projection of the steel pipe P can be restricted, but when the steel pipe P passes through the front end or the rear end. Cannot restrain the projection of the steel pipe P. That is, as shown in FIG. 9, the upper roll receives a force in the direction of the solid line arrow, the lower roll receives a force in the direction of the dotted line arrow, and the escape force described in FIG. The steel pipe P cannot be stably passed through because it is shaken in a direction perpendicular to. Therefore, even in this conventional example, there is a problem in that a guide for passing the material is required and the scratches cannot be completely prevented.

[0005]

SUMMARY OF THE INVENTION In view of the above circumstances, it is an object of the present invention to provide a straightening roll set and a straightening machine for steel pipes, etc., in which straightening accuracy of the pipe end portion is improved and scratches are not generated. .

[0006]

A straightening roll set according to the first aspect of the present invention includes a large-diameter long drum-shaped large roll having a roll axis inclined with respect to a pass line in a horizontal plane. The roll axis is inclined in the direction opposite to the roll axis of the large roll with respect to the line, and is composed of three small rolls of small diameter and short length hourglass shape arranged along the pass line. Of the rolls, the small rolls at both ends sandwich steel pipes and the like between both ends of the large roll, and the intermediate small roll sandwiches steel pipes and the like between the middle portion of the large roll. It is characterized in that a small roll and a large roll are arranged with a pass line interposed therebetween. The straightening machine for steel pipes according to the second aspect of the invention has a roll set of two rolls facing each other on the entry side and the exit side of the straightening roll set of the first aspect of the invention, and one lower roll on the exit side of the straightening machine. It is characterized in that it is additionally arranged.

[0007]

In the straightening roll set of the first aspect of the invention, the steel pipe is passed between the roll sets in which each of the three small rolls and the large roll are arranged to intersect with each other, and the straightening roll set is the same as the conventional two-roll facing type set. Bending is applied while rotating the steel pipe, and repeated bending correction is performed. Then, the steel pipe being straightened is sandwiched by three small rolls and a large roll at three places, and the pop-out force generated in the steel pipe and the like sandwiched between the middle small roll and the center of the large roll is It is regulated by the horizontal extrusion force applied to the steel pipe or the like by the small roll of the section, and the steel pipe is prevented from jumping out. For this reason, there is an advantage that no scratches are generated because a guide is not required. In the straightening roll set of the first aspect of the present invention, bending is effective only when the steel pipe is completely bitten into the three small rolls, so that at the pipe end portion, the three small rolls are completely cut. Since the state of not being bitten occurs, the straightening effect is partly reduced at a part of the pipe end, but since it is repeatedly bent and straightened by the same method as the conventional two-roll straightening machine, it can Compared with a roll-facing straightening machine, it has higher straightening accuracy for the pipe end.

The steel pipe straightening machine of the second invention corresponds to the conventional multi-roll facing straightening machine in which the intermediate roll set is replaced by the straightening roll set of the first invention. The advantage of the first invention that the steel pipe or the like can be stably passed when the rear end is passed and scratches do not occur is inherited as it is. Moreover, since the advantages of the conventional multi-roll opposed straightening machine, namely, the constraint force of the steel pipe and the high number of bends, can be exhibited, the accuracy of straightening a large bend over the entire length of the steel pipe is high. Therefore, according to the straightening machine of the second aspect of the present invention, the straightening accuracy of the pipe end is as high as that of the conventional two-roll facing type, and the straightening accuracy of the large bend is the same as that of the conventional multi-roll facing type. It is possible to prevent the occurrence of scratches.

[0009]

Embodiments of the present invention will now be described with reference to the drawings. The following examples are steel pipe straightening machines corresponding to the configuration in which the straightening roll set of the first invention is substituted for the conventional 7 roll facing type intermediate roll. In FIG. 1, reference numeral 10 denotes a housing composed of an upper frame 11 and a lower frame 12, and three small rolls 1,
2, 3 are mounted by upper brackets 14a, 14b, 14c, respectively, and one large roll 4 is mounted by a lower bracket 14d at the center of the upper surface of the lower frame 12. On the entrance side of the housing 10, the upper roll 5 is attached to the upper frame 11 by the upper bracket 13a, and the lower roll 6 is attached to the lower frame 12 by the lower bracket 13b. Furthermore, on the exit side of the housing 10,
The upper roll 7 is attached to the upper frame 11 by the upper bracket 15a.
And the lower rolls 8 and 9 are attached to the lower brackets 15b and 16
Is attached to the lower frame 12. The symbol L indicates a pass line.

The small rolls 1, 2 and 3 and the large roll 4
Is a straightening roll set which is an embodiment of the first invention, and the rolls are all hourglass-shaped.
3 is a small diameter and short length, and large roll 4 is a large diameter and long length. The curvature of the large roll 4 is determined so as to bend the steel pipe to be straightened, and the three small rolls 1, 2, 3
Is determined according to the curvature of the large roll 4. The upper rolls 5, 7 and the lower rolls 6, 8,
Reference numeral 9 is a medium-diameter medium-sized straightening roll having a drum shape.
A drive motor (not shown) is connected to each of the large rolls 4 except the small rolls 1, 2, 3 and each of the upper and lower rolls 5, 6, 7, 8 to drive them to rotate.
Also, the lower roll 9 on the exit side of the pass line is configured to operate as an idle roll. In this case, a peripheral speed difference does not occur between the small rolls 1, 2, 3 and the large roll 4, which is preferable. However, if the small rolls 1, 2 and 3 are driven independently of the large roll 4 and the rotation speed is controlled, they can be operated as drive rolls. Each compact roll 1, 2 and 3 and the upper rolls 5 and 7 have a rolling down device.
21,22,23,25,27 are attached, and the amount of reduction can be adjusted according to the outer diameter of the steel pipe to be straightened. Further, each of the upper and lower rolls 1 to 9 is attached such that the axial angle is variable. Further, the lower rolls 4, 6, 8 and 9 are also provided with lifting devices. Lower roll 4 moves up and down, rolls 6 and 8
The pipe can be bent between and. Further, the roll 9 is vertically adjusted to finely adjust the bending amount between the roll 9 and the roll 8. The rolls 6 and 8 are adjusted up and down by the amount of roll wear in order to keep the roll upper surface constant.

Next, the details of the straightening roll set will be described with reference to FIG. Each of the small rolls 1, 2, 3 and the large roll 4 is inclined in the horizontal plane with respect to the pass line L, and the axial angles θ1, θ2, θ3, θ4 thereof are about 30 degrees. It is appropriately changed according to the outer diameter and the bending curvature of the steel pipe P. The direction of the roll axis inclination is small rolls 1, 2, 3
And the large roll 4 are in opposite directions to each other, so that the roll axes of the small rolls 1, 2 and 3 intersect with the roll axis of the large roll. Then, among the three small rolls, the intermediate small roll 2 is arranged so as to sandwich the steel pipe P at the central portion of the large roll 4, and the small rolls 1 and 3 at both ends are formed of the steel pipe at both ends of the large roll 4. The pass line L is sandwiched so as to sandwich P.

Next, the straightening action and the pop-out preventing action of the straightening roll set will be described. Small rolls 1, 2,
When 3 and the large roll 4 are rotated to pass the steel pipe P, the steel pipe P is rotated by the roll and is advanced in the direction of the white arrow while rotating around its own axis. In this case, the amount pushed down by the small rolls 1, 3 at both ends of the large roll 4 is δ, whereby the steel pipe P is repeatedly bent, and the bend is corrected.

In the present invention, during the above-mentioned straightening operation, the projection of the steel pipe P is effectively prevented, and the principle thereof will be described with reference to FIGS. FIG. 3 shows A-line, O-line, and C-line arrow views of the pressing position of the small roll 2 which is an intermediate roll among the three small rolls shown in FIG. First, paying attention to the view from the line A arrow, the small roll 2 pushes down the steel pipe P as shown by the dotted arrow, and as a result, the pushed steel pipe P generates a force to return upward due to its elasticity. To do. However, since the small roll 2 is an obstacle, the small roll 2 and the large roll 4 try to move in the direction with the larger distance, that is, to the right. This is the ejection force Xa toward the right side of the steel pipe P at the position of line A (hereinafter, the right side and the left side are based on the direction of travel of the pass line). Since the contact points between the upper and lower rolls 2 and 4 and the steel pipe P are deviated from the perpendicular line passing through the center of the steel pipe P, the horizontal component force (solid arrow) of the pressing force of the small roll 2 and the reaction force of the large roll 4 are Horizontal force components (solid arrows) occur, but they are in opposite directions and cancel each other out.

At the O line position, the bending return direction is set to the large roll 4
The steel pipe P does not generate a popping force because it is received at
At the line position, the pushing-down force by the small roll 2 acts, so that the pop-out force Xb of the steel pipe P is generated for the same reason as the case of the line A position. However, B of upper and lower rolls 2 and 4
Since the profile on the line is bilaterally symmetrical to the profile on the line A, the ejection force Xb is on the left side in the opposite direction to the ejection force Xa in the horizontal plane. The ejection forces Xa and Xb of the steel pipe P are indicated by the same reference numerals in FIG.

FIG. 4 is a C-line and D-line arrow view showing the pressing position of the small roll 3, which is the end roll of the three small rolls shown in FIG. Focusing on the view from the C line arrow, the pressing force of the small roll 3 (dotted arrow) and the reaction force of the large roll 4 (dotted arrow) against it are generated, but the steel pipe of the pressing force and the reaction force is generated. The contact point for P is on the left side of the perpendicular line passing through the center of the steel pipe P, and therefore horizontal component forces Уc3 and Уc4 that are directed to the right side are generated. This horizontal component force Уc3, У
The synthetic force of c4 is denoted by Уc. In addition, as shown in the D line arrow view, since the contact point of the support reaction force (dotted line arrow) of the large roll 4 is located on the left side of the perpendicular line passing through the center line of the steel pipe P at the D line depressed position, Right horizontal component force Уd is generated.
The combined force of these rightward horizontal component forces Уc and Уd is denoted as У3, and both are shown in FIG.

As for the small roll 1 which is the other end roll, horizontal component force is generated as in the case of the small roll 3 described above, but the profiles of the upper and lower rolls 1 and 4 are those of the upper and lower rolls 3 and 4. Since and are symmetrical, the horizontal component force У1 has the same magnitude as the horizontal component force У3 of the small roll 3, but the direction is opposite. FIG. 2 shows the same reference numerals for the horizontal component force У1 in this small roll 1.

Now, as shown in FIG. 2, the pushing force Xb of the small roll 3 to the right opposes the leftward ejecting force Xb of the steel pipe P on the lower surface of the small roll 2, and the steel pipe P is opposed.
Of the steel pipe P on the lower surface of the upper roll 2 against the rightward ejection force Xa of the steel pipe P by the pushing force У1 to the left of the small roll 1 to prevent the steel pipe P from ejecting. Will be done. Therefore, in this embodiment, it is not necessary to provide a guide, and therefore, scratches do not occur. Therefore, according to the steel pipe straightening machine of the present embodiment, it is possible to accurately correct a large bend over the entire length of the pipe, and also to correct the bend of the pipe end portion, and to obtain a steel pipe without scratches. it can.

Next, another embodiment of the present invention will be described.
Although the embodiment has been described as a straightening machine for steel pipes, it can also be applied as a straightening machine for round bars. The above embodiment is an example in which the straightening roll set of the first invention is applied to the intermediate roll in the conventional 7-roll facing straightening machine, but various types such as a 6-roll facing type or an 8-roll facing type are used. It may be applied to a roll facing type straightener. The straightening roll set of the first invention may be used alone. Further, the constitution of the straightening roll set of the first invention is upside down from the roll arrangement in the above embodiment, the large roll 4 is arranged above the pass line, and the small rolls 1, 2, 3, 3.
May be arranged below the pass line.

[0019]

According to the present invention, a high pipe end straightening accuracy similar to that of the conventional two-roll opposed type and a high large bend straightening accuracy similar to that of the conventional multi-roll opposed type are achieved, and the slipping is achieved. It is possible to prevent the occurrence of scratches.

[Brief description of drawings]

FIG. 1 is a front view showing a steel pipe straightening machine according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a straightening roll set according to an embodiment of the first invention.

FIG. 3 is a view as seen from arrows A, O, and B in FIG.

FIG. 4 is a view as seen from arrows C and D in FIG.

FIG. 5 is a roll arrangement diagram of a conventional 6-roll facing straightening machine (I), a 7-roll facing straightening machine (II), and an 8-roll facing straightening machine (III).

FIG. 6 is a front view (I) and a plan view (II) of a conventional two-roll opposed straightening machine.

FIG. 7 is an explanatory diagram of generation of a popping force of a steel pipe in a conventional example.

FIG. 8 is a front view of a conventional multi-roll facing straightener.

FIG. 9 is an explanatory diagram of generation of a popping force of a steel pipe in a conventional example.

[Explanation of symbols]

1 small roll 2 small roll 3
Small roll 4 Large roll 10 Housing 11
Upper frame 12 Lower frame P Steel pipe L
Path line

Claims (3)

[Claims] 1. A large-diameter and long drum-shaped large roll in which the roll axis is inclined with respect to the pass line in a horizontal plane, and the roll axis of the large roll is the roll axis with respect to the pass line. It consists of three small-diameter and short drum-shaped small rolls arranged along the pass line, tilted in the direction opposite to the axis, and the small rolls at both ends of the three small rolls are the large rolls. The steel pipes are sandwiched between both ends, and the small roll in the middle sandwiches the steel pipes between the middle rolls of the large roll, and the three small rolls and the large roll are sandwiched by a pass line. A straightening roll set characterized by being arranged. 2. A straightening machine for a steel pipe or the like, characterized in that two roll-opposing roll sets are arranged on the entrance side and the exit side of the straightening roll set according to claim 1, respectively. 3. A straightening machine for steel pipes and the like according to claim 2, wherein one lower roll is additionally provided on the exit side of the straightening machine for steel pipes and the like.