JPH01262004A - Rolling mill - Google Patents

Abstract

PURPOSE:To reduce the equipment cost and to improve the productivity by composing a couple of upper and lower rolling rolls of tapered rolls of the same shape and arranging roll rotation shafts to be in parallel and to be point symmetrical in upper and lower positions. CONSTITUTION:A couple of upper and lower rolling rolls 1 is composed of rolls whose taper monotonously increases or decreases from one end to the other end. Further, respective rolls 1 are installed in point symmetrical positions in upper and lower positions so that their rotation axises are in parallel. Respective integrated upper and lower torque values are equal to each other by installing the tapered rolls 1 in parallel to be point symmetrical state because a peripheral speed at each point increases or decreases according to a diameter at the point. A rolling load distribution decreases from the width center to width edges and an integrated value of the loads reduces than that at an equal speed. Thus, a required strength of the device is reduced, so that the equipment cost is reduced. The productivity of the device is improved because high draft rolling is performable.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a rolling mill for metal strips.

[Conventional technology]

In recent years, in the rolling industry, from the viewpoint of improving productivity and reducing production costs, there has been a strong demand for high-reduction rolling, which reduces the thickness of a sheet as much as possible in one rolling.

However, when high reduction rolling is performed, the rolling load increases significantly, which poses problems not only in terms of the strength of the equipment, but also in the large deflection of the rolls, resulting in uneven thickness distribution in the width direction.

To solve this problem, in conventional rolling mills, as shown in Figure 8, the circumferential speeds of the upper and lower rolling rolls 1/ and 1// are set to true speed, and the load is significantly reduced at the same rolling reduction rate. was adopted.

[Problem to be solved by the invention]

By the way, in this conventional method, as shown in Figure 4, depending on the speed ratio of the upper and lower rolls, the driving torque of one roll will be a positive value, and the driving torque of the other roll will be a negative value, and the sum of both will be the upper and lower rolls. Since the torque must be approximately equal to the torque when the rolls roll at the same speed, 1, the absolute value of one roll torque during true speed rolling is 3 to 3 compared to that during constant speed rolling.
It reaches 4 times bτ. The rolling reduction rate is limited by the strength of the roll neck and the drive shaft, and there is a problem in that it cannot be used in hot rolling mills with particularly thick plates.

The reason for this is that when the upper and lower rolls are rolled at true speed, at the contact point between the rolled material and the rolls, the slow rolls receive frictional stress in the direction of being driven by the plate, and the fast rolls receive frictional stress in the direction of being braked by the plate. This condition occurs over the entire width of the board.

On the other hand, when a frictional force in the opposite direction acts on the upper and lower surfaces of the plate, the rolling load stops increasing the rolling pressure near the center of the contact area between the plate and the roll, as shown in Fig. 5. When the speed ratio becomes steeper, the rolling load decreases significantly.

The present invention solves the above problems and provides a rolling mill that has the effect of reducing rolling load and does not increase the torque acting on the rolls or drive shaft.

[Failure to solve the problem]

For this reason, in the rolling mill of the present invention, a pair of rolling rolls facing each other with the rolled material sandwiched in between are configured as tapered rolls of the same shape, and the rotating axes of the rolls are arranged in parallel so that the rolls are point symmetrical at the top and bottom. It is characterized by its placement.

[Effect]

In the above-described rolling mill of the present invention, when tapered rolls having different diameters are driven in the axial direction, the peripheral speed at each position of the tapered roll is proportional to the diameter, and the speed is slow in the small diameter part and slow in the large diameter part. It gets faster.

If tapered rolling rolls whose diameters monotonically change in the axial direction are placed above and below in a point-symmetrical manner, the circumferential speeds of the upper and lower rolls will also have a point-symmetrical distribution, and at the center of the point symmetry, the circumferential speeds of the upper and lower rolls will be equal, and at the center of the point symmetry. The difference in circumferential speed between the upper and lower rolls increases as the distance from the upper and lower rolls increases.

At this time, the distribution of torque per unit width of the plate is as shown in FIG. 6, where the roll diameter is negative on the small diameter side and increases as the diameter increases. Since this distribution is also point symmetric, the torque value integrated over the entire plate width is equal at the top and bottom. In addition, the distribution of rolling load decreases as the speed difference between the upper and lower rolls increases, so as shown in Figure 7, the distribution of rolling load decreases from the center of the strip width toward the width edges, and its integral value is constant. lower than the case. The rate of reduction in this rolling load increases as the change in the diameter of the rolling rolls in the axial direction increases because the speed difference increases.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 shows a first embodiment of the present invention, which is a two-high rolling mill having a pair of upper and lower rolling rolls. 1 is a rolling roll configured in a tapered shape so that the roll diameter increases or decreases monotonically from one end to the other; 2 is a rolled material such as metal; 3 is a bearing box; 4 is a block; 5 is a screw; 6 is the housing.

The tapered rolls 1 are arranged in opposite directions so that the upper and lower sides are point symmetrical.

FIG. 2 shows a second embodiment of the present invention, in which a pair of rolling rolls are divided into axially divided reinforcing rolls 7 that are individually rotatable.
It is supported by 8 is a support frame for the reinforcing roll 7. If the tapered rolling rolls 10 have different circumferential speeds in the axial direction and are supported by one reinforcing roll, 1. This prevents a large gap from forming between the reinforcing roll 7 and the tapered rolling roll 1 and causing wear and seizure of the roll.

FIG. 3 shows still another third embodiment of the present invention, in which the diameter of the reinforcing roll 7' is also made to change monotonically in the axial direction, and the diameter between the driven reinforcing roll 7' and the rolling roll 10 is Prevents slipping.

〔Effect of the invention〕

As described above, the rolling mill of the present invention provides the following effects.

(1) A method that makes it extremely easy to make the upper and lower rolling torques the same.
Since the rolling load can be reduced, the problem of reinforcing equipment strength can be solved.

(2) The problem of deterioration of the shape of the rolled metal strip is eliminated, high reduction rolling is possible, and productivity improvements and product cost reductions can be expected.

[Brief explanation of the drawing]

Fig. 1 is a front view of the first embodiment of the rolling mill of the present invention, Fig. 2 is a front view of the second embodiment, Fig. 3 is a front view of the third embodiment, and Fig. 4 is the speed of the rolls. The relationship between the ratio and roll torque, Figure 5 shows the relationship between the speed ratio of the rolls and the rolling pressure in the contact area between the plate and the roll, and Figure 6 shows the relationship between the torque per unit width acting on the roll when the present invention is implemented. FIG. 7 is an explanatory diagram showing the distribution of the rolling load applied to the rolls when the present invention is implemented, and FIG. 8 is a front view showing the rolling rolls of a conventional rolling mill. 1.1', 1''...Rolling roll, 2...Rolled material, 3
, 3'... Bearing box, 4... Block, 5... Screw, 6... Housing, 7, 7'... Reinforcement roll, 8... Support frame. - Ryo 6 agon, 1P15 shaku so-called 7 seki

Claims (1)

[Claims] (1) A pair of rolling rolls that face each other with the rolled material sandwiched in between are configured as tapered rolls of the same shape, and the rotational axes of the rolls are arranged in parallel so that the rolls are point symmetrical above and below. rolling mill.