JP3308924B2 - Wire rolling mill - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire rolling mill in which two four-roll rolling mills are combined, and more particularly, to a wire rolling mill which is disposed in the last two passes of a wire rolling line to expand the size-free range and increase equipment costs. The present invention relates to a wire rod rolling mill capable of reducing the amount of wire.

[0002]

2. Description of the Related Art Two 4-roll rolling mills are used as final finishing rolling stands in a wire rod rolling line.
Wire rod rolling techniques that are arranged in series with a shift of 5 ° are disclosed in, for example, Japanese Patent Publication No. 3-6841 and Japanese Patent Application Laid-Open No. 6-63601. This compound, two disposed a four-roll rolling mill having two pairs of rolls R _1, R ₂ and R _3, R ₄ and round hole die 8 which is disposed orthogonally cross shape a shown in FIG. 5 Thus, a final finishing pass is formed. By using two stands each provided with such a four-roll rolling mill in series, it is possible to widen a size range in which rolling can be performed only by changing a roll gap using rolls of the same hole type, a so-called size-free range. On the other hand, when performing wire rolling using conventional two rolls or three rolls, it is necessary to prepare a dedicated hole for each wire size, so that the number of sizes that can be manufactured is limited, and There is a limit in dimensional accuracy due to widening deformation.

In the above-mentioned conventional example, one mill motor (hereinafter simply referred to as a motor) is provided for each of the two four-roll rolling mills used as the final pass, and the two four-roll rolling mills are used for each. It is driven to rotate by another motor.

[0004]

However, when two four-roll mills each having a motor are arranged in series, the interference between the motor spaces must be avoided, so that the distance between the stands is naturally limited. Therefore, it has the following problems. Since the installation space for the two stands of the final finishing pass must be large, it is difficult to save space and reduce equipment costs.

[0005] When the distance between the stands is long, the wire naturally rotates between the two stands. Thus, the upstream 4
Since the cross section of the wire rod that has passed through the roll rolling mill has a shape close to a substantially square, a product having a circular cross section can be obtained by rolling this with a downstream 4 roll rolling mill by shifting the rolling direction by 45 °, In order to maintain the correct rolling direction, rotation of the rectangular wire between both stands must be avoided. Therefore, conventionally, an expensive roller guide must be provided between both stands in order to maintain the posture so that the rectangular cross section does not rotate, and it is difficult to reduce the equipment cost.

[0006] The four-roll rolling mill can change the rolling size in a stepless manner (size-free rolling) only by changing the roll gap using the same roll hole die.
It is necessary to maintain an appropriate rolling speed according to the size.
However, when one motor is used to drive two 4-roll rolling mills, the rolling speed is limited by an adjustable range.
It is difficult to expand the size-free rolling range.

[0007] Since the rolling speed and the required torque are largely different between the large-diameter material and the small-diameter material, it is necessary to use a large-sized material to drive a wide range of wire rods while driving two four-roll mills with one motor. Since a displacement motor is required, cost increases are unavoidable. Therefore, the present invention has been made to solve such problems of the prior art, and drives two four-roll rolling mills arranged on two stands of a final finishing pass by one common motor. Further, it is an object of the present invention to provide a wire rod rolling mill that can easily reduce equipment cost, expand a size-free rolling range, downsize a motor, and the like.

[0008]

In order to achieve the above-mentioned object, a wire rod rolling mill according to the present invention comprises two 4-roll rolling mills disposed at the end of a continuous finishing rolling line for wire rods. Between one motor and one motor that drives
It is characterized in that a switching gearbox dedicated to a roll rolling mill and a common switching gearbox connected to the dedicated switching gearbox and the other four-roll rolling mill are provided.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram of a continuous finishing rolling line for a wire rod equipped with the wire rod rolling mill of the present invention as the last two passes. In this line, after a finishing rolling mill group Ls for processing a base material S having undergone a rough rolling mill group and an intermediate rolling mill group (not shown) into a circular cross section, two 4
Roll rolling mills P1 and P2 are arranged in series with their rolling directions shifted by 45 °.

[0010] The configuration of the finishing mill group Ls in this case is as follows.
There is no particular limitation. Shown are n stands L
Although the rolling direction of the finishing rolling mill composed of s _{1 to} Ls _n is alternately changed in the horizontal and vertical directions and the HV is alternately arranged, any other type may be used. First, the base material S having a square cross section is subjected to caliberless rolling while alternately changing the rolling direction between a vertical direction and a horizontal direction by flat rolls of a rough rolling mill group, thereby gradually reducing the base material cross-sectional area. . Subsequently, the intermediate rolling mill group is used, and the finishing rolling mill group Ls is alternately pressed down from the vertical direction and the horizontal direction by the oval hole type and the round hole type to form a circular cross section. Finally, the wire rod is finished to a wire having a predetermined wire diameter through the round hole dies of two 4-roll rolling mills P1 and P2 shifted in the rolling direction by 45 °.

The four-roll rolling mills P1 and P2 arranged as the last two passes are commonly driven by one motor M. Then, between each of the four-roll rolling mills P1 and P2 and the motor M,
Switching gearboxes 1 dedicated to one roll mill P1 and 2
A common switching gearbox 2 shared by the four 4-roll mills P1 and P2 is provided. A motor is connected to the input shaft of the switching gearbox 2. One of the two output shafts of the switching gearbox 2 is directly connected to the downstream four-roll mill P2, and the other output shaft is connected to the input shaft of the switching gearbox 1. The output shaft of the switching gearbox 1 is connected to the upstream
It is connected to the roll mill P1. Each switching gearbox has a built-in clutch for switching the gear ratio between two stages.

In the wire rolling mill of the present invention, the two four-roll rolling mills P1 and P2 and the one motor M are connected via the two dedicated and shared gearboxes 1 and 2 as described above. The following operation and effects can be obtained because of the connection configuration. (1) The distance between the stands of the two 4-roll rolling mills P1 and P2 can be made closer because there is no need to consider the interference of the motor space as in the case where each of them occupies a dedicated motor. As a result, the rolling mill installation space can be reduced, and the material does not rotate between passes, so that an expensive roller guide conventionally installed between passes becomes unnecessary.

(2) The size-free rolling range can be widened by installing the dedicated switching gearbox 1. FIG.
Drives two 4-roll rolling mills P1 and P2 with one common motor M, and drives the speed increaser on the upstream 4-roll rolling mill P1 side to one kind of gear ratio i ₁ : i ₂ = 1. : Shows the result of conducting a rolling test of a wire rod with the wire rod fixed at 1.060.

That is, when the wire diameter of the input side material having a circular cross section supplied from the finishing mill Ls _n to the four-roll mill P1 on the upstream side is 5.85 mm, only the roll gap adjustment is performed using the same hole type roll. Rollable size range is 5.3 wire diameter
5 mm to 5.60 mm, in other words, the size free range was 0.25 mm. Thus, the wire diameter of 5.85 mm
Rolls R _{1 to} R of the four-roll rolling mill P1
₄ (first pass), the incoming material elongates in the longitudinal direction due to the reduction, is rolled into a substantially square cross section while its outer diameter is reduced, and is further reduced by a four-roll rolling mill P2 on the downstream side (two passes). And rolled into a wire having a circular cross section with a wire diameter of 5.35 mm to 5.60 mm. However, the wire diameter after two passes is 5.
If it exceeds 60 mm, the elongation of the material is too small, so that the tension becomes excessive between one and two passes, and as a result, the material breaks. On the other hand, in rolling with a wire diameter of less than 5.35 mm, conversely, the elongation of the material between one and two passes was too large, so that the compression became excessive and cobbles appeared.

FIG. 3 shows the experimental results of the present invention.
Of the gearbox 1 on the side of the four-roll rolling mill P1 at two different gear ratios i
₁: I_Two= 1: 1.060 (referred to as speed increase ratio A) and
i₁: I _Two= 1: 1.105 (referred to as speed increase ratio B)
Rolled instead. Wire diameter of entry side material is 6.0mm
In the case of speed increase ratio A, the rollable size range is wire diameter
5.50mm to 5.75mm, ie the size free range is
0.25 mm. Next, the clutch of the gearbox 1 is operated.
After rolling and switching to speed increase ratio B,
The size range is 5.25mm to 5.50mm, and the size is
The free range was 0.25 mm. After all, gearbox 1
Rolling by switching the speed increase ratio to two stages of speed increase ratio A and speed increase ratio B
This expands the size-free rolling range to 0.5 mm.
It will be.

(3) Rolling by switching the speed increase ratio of the common switching gearbox 2 enables rolling from small diameter to large diameter by the motor M having a relatively small capacity, and the applicable size range Becomes wider. FIG. 4 schematically shows a change in torque characteristics due to the gear ratio switching of the switching gearbox 2. In the drawing, a region surrounded by a solid line is a high-speed use region using the speed increase ratio C, which is a range corresponding to low, low-lux, and high-speed rolling of small-diameter materials. The area surrounded by the broken line hatching is a low-speed use area using the speed increase ratio D, which is a range corresponding to high torque and low-speed rolling of a large diameter material.

For example, in the case of wire rod rolling, the wire diameter is 5.5 mm.
At a rolling speed of 100 m / s, and at a wire diameter of 19 mm, a rolling speed of 1
If it is set to 6 m / s, the rolling speed range of both wires is 6 times or more. Now, if one motor is used to cope with such a large and small wire diameter without changing the speed increase ratio, a large capacity motor having the motor characteristics indicated by the one-dot chain line in FIG. 4 is required. However, if the switching gearbox 2 is used by switching between the speed ratio C and the speed ratio D, a small-capacity motor with half the motor torque required without switching is sufficient.

In the above-described embodiment, an example in which the speed increase ratio of each of the switching gearboxes 1 and 2 is switched between large and small by a clutch has been described. However, the present invention is not limited to this. A step-change type switching gearbox may be used.

[0019]

As described above, according to the wire rod rolling mill according to the present invention, one motor is arranged for two four-roll rolling mills used for the final two passes, so that the motor space is reduced. This eliminates the need for expensive and expensive roller guides, thus reducing equipment costs.

[0020] One of the four-roll rolling mills is provided with a dedicated switching speed increaser, and by switching the speed increasing ratio to perform rolling, the size-free rolling range can be expanded. By rolling by switching the speed increase ratio of the common switching speed increaser, it is possible to cope with a wide range of wire rod rolling from small diameter to large diameter by the motor M having a relatively small capacity. For example, various effects can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a continuous wire rod finishing line including the wire rod rolling mill of the present invention as the last two passes.

FIG. 2 is an experimental result showing a size-free rolling range when a speed increase ratio of a four-roll rolling mill is fixed to one type.

FIG. 3 is an experimental result showing a size-free rolling range in a case where the speed increase ratio of one 4-roll rolling mill can be switched between two types.

FIG. 4 is a diagram illustrating a change in motor torque characteristics due to switching of a speed increase ratio of a common switching speed increaser.

FIG. 5 is a front view of a roll arrangement of a four-roll rolling mill.

[Explanation of symbols]

P1 Upstream 4-roll mill P2 Downstream 4-roller 1 Dedicated switching gearbox 2 Common switching gearbox M Motor R ₁ roll R ₂ roll R ₃ roll R ₄ roll S Rolled material

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-9-225502 (JP, A) JP-A-9-172703 (JP, A) Patent 2527283 (JP, B2) US Patent 5363682 (US, A) ( 58) Field surveyed (Int.Cl. ⁷ , DB name) B21B 1/16-1/20 B21B 13/10 B21B 35/00-35/14

Claims (1)

(57) [Claims] 1. A special four-roll mill between two four-roll mills disposed at the end of a continuous finishing rolling line for a wire and one motor that drives them in common. A wire rolling mill comprising a switching gearbox, a dedicated switching gearbox, and a common switching gearbox connected to the other four-roll rolling mill.