JPH0818048B2 - Rolling mill - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] 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 cost, there is a strong demand for high-pressure rolling in which the sheet thickness is as thin as possible in one rolling.

However, since rolling under a high pressure significantly increases the rolling load, there is a problem that not only the strength of the equipment but also a large deflection of the rolls and a nonuniform sheet pressure distribution in the width direction.

In order to solve this, in the conventional rolling mill, a means for significantly reducing the load at the same reduction rate by adopting different peripheral velocities of the upper and lower rolling rolls 1 ′, 1 ″ as shown in FIG. Was.

[Problems to be Solved by the Invention]

By the way, in such a conventional method, as shown in FIG. 4, the driving torque of one roll is a positive value and the driving torque of the other roll is a negative value depending on the speed ratio of the upper and lower rolls, and the total of the two is higher or lower. Since the rolls must have almost the same torque as when they are rolled at the same speed, the absolute value of the torque of one roll at the time of different speed rolling is 3 to 4 in the case of constant speed rolling.
It doubles. For this reason, the rolling reduction is restricted by the strength of the roll neck portion and the drive shaft, and there is a problem in that it cannot be used for a hot rolling mill having a particularly thick plate thickness.

This is because when the upper and lower rolls are rolled at different speeds, frictional stress is applied to the contact part between the rolled material and the roll in the direction in which the slow roll is driven by the plate and in the direction in which the fast roll is braked by the plate. This condition occurs over the entire width of the plate.

On the other hand, when the rolling load exerts reverse frictional forces on the upper and lower surfaces of the plate, the rolling pressure in the vicinity of the center of the contact portion between the plate and the roll does not increase as shown in FIG. 5, and as shown in FIG. The rolling load is significantly reduced when the speed ratio is increased.

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

[Means for solving the problem]

Therefore, the rolling mill of the present invention has a pair of upper and lower rolling rolls that are opposed to each other with the rolling mill interposed therebetween, and the roll diameter is linear over the entire length of the roll configured to monotonically increase or decrease from one end to the other end. It is characterized in that the taper rolls of the same shape are provided with a taper, and the rolls are arranged in opposite directions, and the rotation axes of the rolls are arranged in parallel so that the rolls are point-symmetrical in the vertical direction. .

[Action]

When the above-described rolling mill of the present invention drives a taper roll provided with a linear taper over the entire length of the roll, the peripheral velocity at each position of the taper roll is proportional to the diameter, the small diameter portion is slow, and the large diameter portion is large. The parts will be faster. If the tapered rolling rolls whose diameters change monotonically in the axial direction are arranged point-symmetrically, the peripheral speeds of the upper and lower rolls also have a point-symmetric distribution. The peripheral speed difference between the upper and lower rolls increases as the distance from the roll increases. At this time, in the distribution of torque per unit width of the plate, as shown in FIG. 6, the roll diameter is negative on the small diameter side and the torque increases in the direction in which the diameter increases. Since this distribution is also point-symmetrical, the torque values integrated over the entire plate width are equal in the vertical direction. Further, since the rolling load distribution decreases as the speed difference between the upper and lower rolls increases, the rolling load decreases from the center of the plate width toward the width end, as shown in FIG. Also decreases. The reduction rate of the rolling load increases as the change in the diameter of the rolling roll in the axial direction increases, because the speed difference increases. In practice, in order to obtain an effective reduction rate of the rolling load, the diameter difference between both ends of the roll cylinder length needs to be at least 10% or more of the diameter at the center of the cylinder length, although it depends on the reduction rate.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a first embodiment of the present invention, which is a two-stage rolling mill having a pair of upper and lower rolling rolls. 1 is a rolling roll having a taper shape so that the roll diameter monotonically increases or decreases from one end to the other end, 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 taper rolls 1 are arranged in opposite directions so as to be point-symmetrical in the vertical direction.

FIG. 2 shows a second embodiment of the present invention, in which a pair of rolling rolls are supported by reinforcing rolls 7 which are axially divided and individually rotatable. Reference numeral 8 is a support frame for the reinforcing roll 7. Since the peripheral speed of the tapered rolling roll 1 is different in the axial direction, it is possible to prevent wear and seizure of the roll due to a large slip between the reinforcing roll 7 and the tapered rolling roll 1 when supported by one reinforcing roll. To do.

FIG. 3 shows a third embodiment of the present invention in which the diameter of the reinforcing roll 7'also changes monotonically in the axial direction so that the reinforcing roll 7'and the rolling roll 1 are driven. Prevents slippage.

〔The invention's effect〕

As described above, according to the rolling mill of the present invention, the following effects can be obtained.

(1) Since the rolling load can be reduced very easily by making the upper and lower rolling torques the same, the problem of reinforcing the facility strength can be solved.

(2) The problem of deterioration of the shape of the rolled metal strip disappears, and high-pressure rolling becomes possible, which can be expected to improve productivity and reduce product cost.

[Brief description of drawings]

FIG. 1 is a front view of a first embodiment of the rolling mill of the present invention, FIG. 2 is a front view of the same second embodiment, FIG. 3 is a front view of the same third embodiment, and FIG. 4 is a roll speed. Ratio and roll torque, FIG. 5 shows the relationship between roll speed ratio and rolling pressure in the contact area between the plate and the roll, and FIG. 6 shows distribution of torque per unit width acting on the roll when the present invention is carried out. FIG. 7 is an explanatory view showing distribution of rolling load applied to rolls when the present invention is carried out, and FIG. 8 is a front view showing rolling rolls of a conventional rolling mill. 1,1 ', 1 "... Rolling roll, 2 ... Rolling material, 3,3' ... Bearing box, 4 ... Block, 5 ... Screw, 6 ... Housing, 7,7 '... Reinforcing roll , 8 ... Support frame.

Claims (1)

[Claims] 1. A pair of upper and lower rolling rolls opposed to each other with a rolling mill sandwiched between them is provided with a linear taper over the entire length of the rolls configured so that the roll diameter monotonically increases or decreases from one end to the other end. A rolling mill characterized in that the taper rolls have the same shape and are arranged in mutually opposite directions, and the rotation axes of the rolls are arranged in parallel so that the rolls are pointed vertically.