JP2003251408A - Method for straightening metallic sheet by roll straightening machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a straightening method of a metallic sheet by a roll straightening machine by which the damage of equipment by an excessive shaft torque caused by the difference between loads received with work rolls in the roll straightening machine for correcting the flatness of the metallic sheet. <P>SOLUTION: In the method for straightening the metallic sheet by the roll straightening machine, the roll group of the roll straightening machine are divided into a preceding-stage roll group on the inlet side of the metallic sheet and a succeeding-stage roll group on the outlet side and a clutch is provided in a power transmission device for transmitting drive to the succeeding roll group and the clutch is made to slip when the clutch in the power transmission device of the roll group on the outlet side of the reversing metallic sheet is subjected to a load torque not less than a preset torque. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roll straightening machine for straightening a flatness of a metal plate such as a steel plate, and a power transmission device for transmitting a shaft power of an electric motor to a plurality of work rolls.
Further, the present invention relates to a method for straightening a metal plate in a roll straightening machine, which prevents damage to the equipment due to an excessive axial torque generated due to a difference in loads received by work rolls.

[0002]

2. Description of the Related Art Generally, a roll straightening machine for straightening a flatness of a metal plate is provided with a power transmission mechanism shown in FIG. In FIG. 1, the shaft power of the electric motor 14 is applied to the reduction gear 12
In addition, the front stage roll group 2 via the rotation direction adjusting gear 10,
Primary transmission is performed to the gears 7, 8 arranged on the respective drive shafts 7, 8 for driving the rear roll group 3, and the drive shafts 7, 8 of the respective roll groups are transmitted via the equal distribution gears 5, 6. 2 on each of the drive shafts 4-1 to 4-9 of each work roll 1 constituting the roll group.
A mechanism for transmitting the following is used, and each work roll 1-1
To 1-9, equal torque and the same rotational speed are given with the same direction of roll peripheral speed in contact with the material to be straightened.

In straightening a metal plate, a straightening method is adopted in which the bending curvature on the entrance side of the straightening machine is set to be large, and thereafter the bending curvature is gradually reduced to reduce the residual stress, that is, the pushing amount is gradually decreased from the entrance side to the exit side. Because of the tilting rolling method, the surface of the plate in contact with the work roll has a difference in bending curvature between the roll peripheral speed on the inlet side> plate surface speed and the roll peripheral speed on the outlet side. <Sliding friction that is the plate surface speed is occurring. Therefore, the sliding work friction torque is applied to the work roll on the entry side in addition to the bending work torque, and the work work roll on the exit side receives the friction torque from the material to be corrected, that is,
Since the torque circulation phenomenon occurs, excessive shaft torque that causes equipment damage is generated particularly on the work roll on the entry side.

[0004]

SUMMARY OF THE INVENTION The present invention is a roll straightening machine for straightening a flatness of a metal plate, which is capable of preventing equipment damage due to excessive axial torque generated due to a difference in load received by work rolls. The present invention provides a method for straightening a metal plate.

[0005]

In the present invention, paying attention to such a torque circulation phenomenon, the output side work roll is rotated at a speed higher than that of the input side work roll, so that the input side and the output side work roll bear the burden. The load torque is equalized to prevent the generation of excessive shaft torque.

The specific means are as follows: 1) In a method of straightening a metal plate with a roll straightening machine, the roll group of the roll straightening machine is divided into a front roll group on the inlet side and a rear roll group on the outlet side. A metal plate roll characterized in that a slip clutch is provided in a power transmission mechanism that divides and drives the rear-stage roll group, and the clutch slips when a load torque equal to or greater than a preset torque is applied to the clutch. A straightening method with a straightening machine, and 2) a method of straightening with a roll straightening machine while reversing a metal plate,
The roll group of the roller straightener is divided into at least two roll groups, a slip clutch is provided in each power transmission mechanism that drives both roll groups, and the power of the roll group on the output side of the metal plate to be reversed is provided. A method for straightening a metal plate in a roll straightening machine is characterized in that when a load torque equal to or greater than a preset torque is applied to a clutch in the transmission mechanism, the clutch is slipped.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In flatness correction of a metal plate,
As described above, in order to correct the widthwise elongation difference that is the cause of the plate wave, a large bending curvature is taken at the entrance side of the straightening machine, and then the bending stress is gradually reduced to reduce the residual stress. A tilting reduction method is used in which the pushing amount is gradually reduced from the side toward the exit side. For example, as shown in FIG. 2, in a straightening machine arranged with a work roll diameter: D and a roll pitch interval: L, the plate thickness of the material to be straightened: t, the pushing amount of the work roll: δ, the bending curvature: 1 / From the simple beam bending theory, ρ is given by equation (1).

1 / ρ = 6δ / L ² (1) In that case, the plate surface strain immediately under the work roll: ε is given by the equation (2), and ε ₂ = −t / 2ρ ₂ (2) Plate surface speed immediately below the work roll: V is the speed at the plate center
_{As C} , it becomes like the formula (3).

V = (1−t / 2ρ) V _C (3) It is difficult to uniquely determine the center velocity V _{C of the} plate, but the work roll proceeds while receiving a bending curvature of 1 / ρ. Therefore, it is faster than the peripheral speed V _{R of the} work roll, and as described above, the indentation δ is gradually reduced from the entrance side to the exit side.
Generally, the inlet plate surface speed: Vin <the work roll peripheral speed:
V _R <delivery side surface speed: the relationship of Vout is established.

Accordingly, such a plate surface speed: V and the circumferential speed of the work roll: V the relative speed difference of the _R, the work rolls of the entry side in addition to the bending torque applied is sliding friction torque, the delivery side of the On the contrary, the work roll receives a reverse load torque from the material to be straightened, so that a so-called torque circulation phenomenon occurs, and particularly an excessive work shaft torque that leads to equipment damage is generated in the work roll on the entry side with a large bending torque. . In fact, Figure 1
Using a roller straightening machine having a power transmission mechanism of, a work roll diameter of D280 mm and a pitch interval of L300 mm, the plate thickness t2
0 mm, plate width W4 m, yield stress σ _y 40 kg / mm ^{2 When} the material to be straightened is straightened, the drive shafts 4-1 to 9, drive shafts 7 and 8 of each work roll 1-1 to 9 and the motor shaft 13 includes
The load torque shown in Table 1 was measured. It can be seen that, for example, in the work roll 1-3, an axial load torque of approximately 1.7 times acts as compared with the bending torque T _C obtained by the calculation described together. The reduction ratio between the motor shaft 13 and the drive shafts 7, 8 of the roll group is 1 / 30.72,
It can also be seen that torque circulation occurs in which the torque of the motor shaft 13 and the reverse load torque applied to the drive shaft 8 of the rear roll group 3 become the load torque of the drive shaft 7 of the front roll group 2 via the intermediate gear 10.

For the calculation of the bending torque, first,
The workability: α, which is derived from the equations (1) and (2) and is defined as the ratio of the plate surface strain to the elastic limit strain, is given by the equation (4).
Ask by.

Machining degree α = 3 Et · δ / σ _y L ² …………………… (4) (E: Young's modulus of the material to be straightened) Next, the machining torque (Tc) is derived as a known machining torque. It was calculated by the formula (5).

Tc = (D / 2) (Wtσ _y ² / E) (α-1) ² /α...(5) Power transmission device for a roll straightener for straightening a metal plate, especially a thick plate, to which the present invention is applied The configuration is as shown in FIG. In contrast to the conventional power transmission mechanism shown in FIG. 1, as shown in FIGS. 3 and 4, in the power transmission mechanism of the present invention, the drive shafts 7 and 8 for driving the front stage roll group 2 and the rear stage roll group 3 are driven. By providing the slip clutch 15 or 16 on one or both of them, the transmission torque of the drive shaft located on the exit side of the material to be straightened is arbitrarily adjusted, and the reverse load from the material to be straightened generated on the work roll on the outgoing side. By limiting the torque, it is possible to prevent an excessive axial load torque applied to the drive shaft of the entrance side roll group and the work roll of the entrance side roll group, which is generated by the torque circulation.

That is, as shown in FIG. 3, when the material to be straightened is traveling in the direction from the front roll group 2 to the rear roll group 3, the rear rolls located on the outgoing side with respect to the direction in which the material is straightened. A slip clutch 15 is provided on the drive shaft 8 of the group 3. In this mechanism, if the transmittable torque of the slip clutch 15 is set to be equal to or less than the reverse load torque generated on the drive shaft 8, the circulating torque acting on the drive shaft 7 of the front roll group 2 via the intermediate gear 12 can be reduced. Is possible.

The slip clutch 15 shown in FIG.
As shown in FIG. 5, the structure of 16 is provided so as to penetrate through the reduction gears 9 and 11, and is composed of an outer cylinder 17, an inner cylinder 18 and an air tube 19, and applies air pressure to the air tube 19 from the outside. The air tube is expanded to transmit the torque of the outer cylinder 17 to the inner cylinder 18. When the pressure inside the air tube 19 is made high, a large torque is transmitted to the inner cylinder 18, and when the pressure inside the air tube 19 is made low, the torque transmitted to the inner cylinder 18 is reduced. However, the advancing direction of the material to be straightened is one-way straightening, that is, the advancing direction of the material to be straightened is the front stage roll group 2
The adjustment of the air tube is basically unnecessary in the straightening in the direction of the rear roll group 3.

In the above description, the straightening in one direction in the straightening of the metal plate, that is, the straightening of the material to be straightened from the front roll group 2 to the rear roll group 3 has been described. In, it is possible to reverse straighten the metal plate by further changing the configuration of the roll straightening machine. That is, as shown in FIG. 4, the advancing direction of the material to be straightened is the direction from the front roll group 2 to the rear roll group 3,
Further, by performing the reverse straightening in which the straightening is repeated in the direction from the rear roll group 3 to the front roll group 2, it is possible to further improve the straightening efficiency and shorten the straightening time. When performing this reverse correction, as shown in FIG.
In the power transmission mechanism, a slip clutch 15 in which an air tube 19 is incorporated in each of a drive shaft 7 for driving the front roll group 2 and a drive shaft 8 for driving the rear roll group 3,
An air tube 19 provided with 16 and connected to a roll group 2 or a roll group 3 located at a subsequent stage in the traveling direction of the material to be straightened.
By adjusting the air pressure fed to the drive shaft 7 and setting the transmissible torque to be equal to or less than the reverse load torque generated in the drive shaft 7 or the drive shaft 8, the front stage roll group 2 or the rear stage roll group 3 via the intermediate gear 12 is set. The circulating torque acting on the drive shaft 7 or the drive shaft 8 can be reduced.

More specifically, the work rolls 1-1 to 9 have a roll diameter of 280 mm, and the upper four rolls and the lower five rolls are arranged in a zigzag pattern at a pitch interval L300 mm. The power of the electric motor 14 is first transmitted to the drive shaft 7 for driving the front stage roll group 2 and the drive shaft 8 for driving the rear stage roll group 3 through the deceleration of 1 / 30.72, and is transmitted from the respective drive shafts 7, 8. Is secondarily transmitted to each work roll through the equal distribution gears 5 and 6, and the electric motor has a capacity of 300 kw and a rated torque of 4
Since the rotation speed is 12 kg-m and the rated rotation speed is 710 rpm, the rotation speed of the work roll is 23 rpm and the peripheral speed of the roll is 20 mpm. As shown in FIG. 3, a slip clutch 15 is provided on the drive shaft 8 of the rear roll group 3, and as shown in FIG. 4, when reverse correction is performed, the drive shaft of the front roll group 2 also slips. By providing the clutch 16, 200
The load torque of 0 kg-m causes slippage, and no more torque can be transmitted.

[0018]

[Examples] Table 1 shows a steel plate as a material to be straightened having a plate thickness t of 20 mm, a plate width of W4 m, and a yield stress σ _{y of} 40 kg / mm ² .
Drive shafts 4-1 to 9 and drive shafts of each work roll when flatness is corrected using the conventional straightener shown in FIG. 3 and the straightener of the present invention having the slip clutch shown in FIG. 3 or 4. 7 shows a distribution of load torques measured on the motor shafts 7 and 8. In order to make it easier to understand the effect of the present invention, the specifications of the straightening machine and the work roll pushing amount are set to be the same as those when the present invention is not applied. The slip start set torque of the slip clutch 15 on the steel plate exit side was 2000 kg-m.

As shown in Table 1, in the case of the conventional example to which the present invention is not applied, the bending torque T calculated is calculated.
Compared to c, in the work roll 1-3, about 1.7 times (5151 kg-m / 2955 kg-m) of axial load torque was applied, whereas the embodiment to which the present invention is applied. Is about 1.4 times (4188 kg-m / 2955 kg-m). Further, the drive shaft 8 of the rear roll group 3 stays at a reverse load torque of 2000 kg-m due to the slip clutch, and the drive shaft 7 of the front roll group 2 reaches about 81% (13566 kg-m / 16683 kg-). m)
Has been reduced to.

[0020]

[Table 1]

Further, in FIG. 4, contrary to the above, when the steel plate enters from the direction of arrow B (right side of the drawing), the slip clutch 16 is set to slip. Also in this case, the same effect as in Table 1 could be obtained.

[0022]

According to the present invention, the circulating torque generated inside the power transmission device of the roll straightener is reduced, and a great effect is provided for extending the life of the device and reducing the maintenance cost. Further, by adopting the present invention in the construction of the roll straightening machine, it becomes possible to carry out proper and economical construction without overestimating the mechanical strength margin.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a power transmission mechanism of a roll straightening machine.

FIG. 2 is a diagram illustrating a relationship between a bending curvature and an indentation amount by a roll straightening machine.

FIG. 3 is a diagram showing an outline of a power transmission mechanism of the roll straightening machine of the present invention.

FIG. 4 is a diagram schematically showing a power transmission mechanism in reverse straightening of the roll straightening machine of the present invention.

FIG. 5 is a diagram schematically showing a slip clutch used in the roll straightening machine of the present invention.

[Explanation of symbols]

1-1-9 ... Working roll 2 of roll straightener ... Front roll group 3 ... Rear roll group 4-1-9 ... Roll drive shaft 5 ... Equal distribution gear 6 for transmitting power to work rolls of front roll group 6 ... Rear stage Equal distribution gear 7 that transmits power to the work rolls of the roll group ... Drive shaft 8 of the front roll group ... Drive shaft 9 of the rear roll group ... Reduction gear 10 installed on the drive shaft of the front roll group ... Front roll group and rear stage Intermediate gear 11 for matching the rotation directions of the roll groups ... Reduction gear 12 installed on the drive shaft of the rear roll group ... Reduction gear 13 for transmitting motor shaft torque ... Motor shaft 14 ... Motors 15, 16 ... Slip clutch 17 ... Outside Cylinder 18 ... Inner cylinder 19 ... Air tube

Claims (2)

[Claims] 1. A method for straightening a metal plate with a roll straightening machine, wherein the roll group of the roll straightening machine is divided into a front roll group on the inlet side of the metal plate and a rear roll group on the outlet side thereof, A straightening method in a roll straightening machine for metal plates, characterized in that a slip clutch is provided in a power transmission mechanism for transmitting drive to the group, and the clutch is slipped when a load torque equal to or more than a preset torque is applied to the clutch. . 2. A method of straightening a metal plate by a roll straightening machine while reversing the metal plate, wherein the roll group of the roller straightening machine is divided into at least two roll groups, and each power transmission mechanism drives both roll groups. A metal plate which is provided with a slip clutch and which slips the clutch when a load torque of a preset torque or more is applied to the clutch in the power transmission mechanism of the roll group on the output side of the metal plate to be reversed. Straightening method with a roll straightening machine.