JPH0570918A - Device for restraining vibration of roll in plating bath - Google Patents

Abstract

PURPOSE:To restrain the development of vibration caused by driving system of a roll in plating bath in a hot-clip plating line. CONSTITUTION:Between the rolls 1, 2 in the plating bath 3 in the hot-dip plating line and driving motors 6, 7, hydraulic power transmissions 16, 17 of a hydraulic coupling or a torque converter, etc., are assembled, and the development of the vibration of the rolls 1, 2 in the bath caused by pulsation of angular velocity at between the driving motors 6, 7 and the rolls 1, 2 in the bath, is restrained. By this method, chatter mark, dross defect, etc., of the plated steel sheet caused by the development of the vibration of the support roll in the plating bath are prevented and the surface quality on the plated steel sheet is remarkably improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roll in a plating bath that is immersed in a bath of a hot dip coating line to stabilize the path of a steel strip to be plated and to correct the shape such as warpage. The present invention relates to a device that suppresses generated vibration.

[0002]

2. Description of the Related Art In recent years, the demand for surface-treated steel sheets such as hot-dip galvanized steel sheets which are excellent in corrosion resistance, weldability and paintability is rapidly expanding. A typical method for producing a hot dip plated steel sheet of this surface-treated steel sheet is as shown in FIG. 2, and the steel strip 21 to be plated whose surface has been cleaned and activated by a continuous annealing furnace (not shown).
Is immersed in the plating bath 22, the traveling direction is changed by a sink roll 23 in the bath, and the plating bath 2 is passed through a collecting roll 24 and a stabilizing roll 25.
Pulled up from 2. And the wiping nozzle 2
A compressed gas such as air is jetted from 6 to squeeze out the excess plating solution to adjust the amount of coating adhesion.

The collecting roll 24 of the hot dip coating line is a shape correcting roll for correcting the warp of the plated steel strip, and the stabilizing roll 25 is a pass stabilizing roll of the plated steel strip. And is commonly called a support roll. These support rolls are most ideal to be used in a non-driving state in terms of the surface quality of the plated steel strip, but in reality the winding angle and roll diameter of the roll are small, so When the width is small or the tension of the plated steel strip is small, it is difficult to rotate in synchronization with the line speed in the non-driving state. In addition, if rotation failure occurs due to damage to the roll bearing, scratches will occur on the plated steel strip.In many cases, a drive system that drives the roll in the bath from outside the plating bath via the drive shaft is adopted. ing.

As shown in FIG. 3, the drive device for the support rolls in the plating bath has a structure in which the support rolls 24, 25 are immersed in the plating bath 22 for use. Therefore, the drive shafts 27, 28 are respectively plated. It has penetration angles α ₁ and α ₂ with respect to the bath. Therefore, from the drive motor 29 to the speed reducer 30, the constant velocity joint 31, the drive shaft 2
7 and 28, the rotational speed transmitted to the roll shaft via the in-bath couplings 32 and 33 is not constant speed transmission because of the penetration angles α ₁ and α ₂ of the drive shafts 27 and 28, and will be described in detail later. Derive the pulsation of angular velocity. For this reason, the support rolls 24 and 25 are vibrated, and as a result, surface quality defects such as chatter marks, chatter marks, and dross defects are generated on the surface of the plated steel strip. When the steel strip is manufactured, its commercial value is significantly impaired.

As a known technique for preventing the vibration of the coated steel strip in the hot dip coating line, the coated steel strip is located near the wiping nozzle and faces the edge portion of the coated steel strip from the outer side in the width direction and is coated with a permanent magnet. An apparatus in which magnetic means for vibration prevention that applies tension in the width direction in a non-contact state is arranged (Japanese Patent Laid-Open No. 57-85964), and a supporting frame is horizontally arranged above the wiping nozzle with both sides of the plated steel strip sandwiched therebetween. Then, a vertical shaft vertically hung downward on two bases supported on both sides of the support frame so as to be horizontally movable comes into contact with both ends of the plated steel strip so as to be horizontally rotatable via bearings. A pair of upper and lower vibration-preventing rolls are provided, one of the vibrating rolls obliquely projects from one end of the plated steel strip toward the other end, and the other obliquely projects from the end toward the other face of the plated steel strip. To stick out to each other Insert by placing the device (JP-A-62-
No. 238357) has been proposed.

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The devices disclosed in Japanese Patent Laid-Open No. 964 and Japanese Patent Application Laid-Open No. 62-238357 are for suppressing the vibration of the plated steel strip that has occurred, and do not suppress the cause of the vibration of the plated steel strip itself. However, since it cannot be a fundamental solution to the above-mentioned problem, a sufficient effect cannot be achieved.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an apparatus for suppressing the vibration of a plated steel strip due to a roll in a plating bath of a hot dip coating line.

[0008]

[Means for Solving the Problems] The inventors of the present invention have conducted earnest research to achieve the above object. As a result, the vibration of the roll in the plating bath causes the drive shaft of the roll in the bath to have an invasion angle with respect to the plating bath, so that the velocity of the vibration is not constant and the pulsation of the angular velocity occurs in the coupling portion. This is because the pulsation serves as a vibration source and induces vibration between the bath roll having a large moment of inertia and the drive motor.
The vibration of the in-bath roll is remarkable when the peripheral speed of the in-bath roll rotated by the movement of the plated steel strip is higher than the peripheral speed (drive speed) of the in-bath roll rotated by the driving force of the drive motor. I found out what was happening. Such a state occurs when the roll in the bath rotates in synchronization with the moving speed of the plated steel strip. When the peripheral speed of the bath roll rotated by the movement of the plated steel strip is higher than the roll drive speed of the drive motor, the drive force is applied from the bath roll side to the drive motor side, causing the drive motor to over rotate. Then, the generation of vibration is promoted. To prevent the occurrence of vibration when the peripheral speed of the in-bath roll is higher than the drive speed of the drive motor and the peripheral speed of the in-bath roll becoming significantly smaller than the line speed, the drive system of the in-bath roll should be It was found that it is effective to provide a fluid transmission device such as a fluid coupling or a torque converter, and the present invention has been reached.

That is, according to the present invention, a fluid transmission device such as a fluid coupling or a torque converter is provided between the roll in the plating bath of the hot dip coating line and the drive motor.

[0010]

The bath coupling for connecting the roll shaft of the roll in the plating bath and the drive shaft is a cross pin system, which is a 4-pin system shown in FIG. 4 (a) for desorption in the bath and a simple structure. Is often adopted. In this case, as shown in FIG. 4B, the angle ψ ₁ projected from the y-axis direction of the I-axis (θ ₁ ) is tan ψ ₁ = tan θ ₁ · cos γ,
Similarly, the angle ψ ₂ projected from the y direction of the J axis is tan ψ ₂
= Tan θ ₁ × 1 / cos γ. This is illustrated in FIGS. 5 (a) and 5 (b) when ψ ₁ , ψ ₂ and ψ _i −θ ₁ (i = 1, 2) are illustrated with θ ₁ as a variable. For this reason,
A gap of Max | ψ ₁ −ψ ₂ | is given as an initial gap to the groove portion in contact with the cross pin on the output shaft (D-axis) side of the coupling in the bath. Consider power transmission with a cross pin in this bath. In this case, for the sake of simplicity, assuming that the output shaft side (D-axis side) always brakes the input shaft side (E-axis side), the relationship between the D-axis and the cross pin viewed from the y-axis direction is , Θ = 0, θ = π / 2, θ = π, both I-axis and J-axis contact the power transmission surface, and when 0 ≦ θ ≦ π / 2, only the J-axis side transmits power and the I-axis Is away from the power transmission surface, and π / 2 ≦
When θ ≦ π, only the I-axis side transmits power and the J-axis is away from the power transmission surface. This is shown in an angle diagram in FIG.
(A) As shown in the figure, the input shaft (E-axis) to the output shaft (D
6 (b) due to the angle fluctuation when transmitting rotation to the shaft)
As shown in the figure, pulsation of angular velocity occurs in the cross pin in the bath.

Looking at the drive system of the bath in the hot dip galvanizing line, the transmission characteristics of the universal joint are that it is driven by the motor side coupling between the reduction gear and the drive shaft and the bath coupling between the drive shaft and the roll shaft. transfer characteristic between the motor and the bath roll, as shown in FIG. 7, results in pulsation of the angular velocity cases, driven bath roll having a large moment of inertia the pulsation becomes vibration source (GD ²⁾ Induce vibration between the motors. Or the use of cross pin type coupling bath, pulsation of the angular velocity is inevitable, causing between the drive motor and roll the pulsation becomes GD ² large, to induce vibration, pulsation of the shafting The purpose of this invention is to alleviate, absorb, and excise.

Further, by absorbing and adjusting the velocity pulsation transmitted from the roll side in the bath to the drive motor side, the pulsation generated at the cross pin portion is generated only at the spindle portion having a small GD ² , ^It does not occur between the ^two largest motors, reducers and rolls.

According to the device of the present invention, the fluid transmission device such as the fluid coupling or the torque converter incorporated between the drive motor of the roll in the plating bath of the hot dip coating line and the roll shaft is a device for transmitting a fluid as a medium. Therefore, since it has a characteristic that it is difficult to follow a rapid speed change, it has a characteristic of cutting off vibration or impact of the shaft system or absorbing or mitigating it. Therefore, the pulsation of the angular velocity generated at the cross pin portion is absorbed and relaxed by the fluid transmission device, and as shown in FIG. 8, it hardly occurs between the drive motor, the speed reducer and the bath roll. Further, since the load fluctuation on the roll side in the bath is freely absorbed and adjusted by the fluid transmission device, it is prevented from affecting the drive motor side, and the roll in the bath and the drive motor due to the load change on the roll in the bath are prevented. Generation of vibration between the two is suppressed. That is, the rotational speed of the driven shaft of the fluid transmission device is automatically and freely changed according to the load change of the roll in the bath, and the condition for suspending the load is maintained. As the fluid transmission device, a fluid coupling and a torque converter have been mentioned, but any device that has a mechanism capable of following the load fluctuation on the roll side in the bath and can absorb and relax the pulsation of the angular velocity of the coupling part may be used. ..

[0014]

【Example】

Example 1 Hereinafter, a vibration preventing device for a support roll in a hot dip bath according to the present invention will be described with reference to FIG. FIG. 1 is an explanatory view of a vibration suppressing device for a roll in a plating bath according to the present invention. In FIG. 1, since the support rolls 1 and 2 are used by being immersed in the plating bath 3, the drive shafts 4 and 5 each have an intrusion angle with respect to the plating bath. Therefore, from the drive motors 6 and 7, the speed reducers 8 and 9, the constant velocity joints 10 and 11, the drive shafts 4 and 5, the cross pin type coupling 12 in the bath,
The rotational power transmitted to the roll shafts 14 and 15 via 13 does not perform constant velocity conduction as described above due to the penetration angle of the drive shafts 4 and 5, and causes pulsation of angular velocity. As a countermeasure, the torque converters 16 and 17 are incorporated in place of the Loveflex couplings in front of the speed reducers 8 and 9, and the coupling 1 in the bath depending on the penetration angles of the drive shafts 4 and 5 is used.
Pulsation with angular velocity of 2, 13 etc. and support roll 1,
The load fluctuations on the second side are freely relaxed, absorbed, and adjusted by the torque converters 16 and 17.

Due to the above-mentioned structure, the pulsation of the rotational power generated in the constant velocity joints 10, 11 and the couplings 12, 13 in the bath due to the penetration angles of the drive shafts 4, 5 is caused by the torque converters 16, 17. Be absorbed. Further, with respect to the load fluctuation of the support rolls 1 and 2, the torque converters 16 and 17 automatically change the driven shaft rotation speed in accordance with the fluctuation of the driven shaft torque, so that the driving shaft torque is not much affected. Therefore, the drive motors 6 and 7
Does not over-rotate and always operates within the desired range. Therefore, the pulsation of the angular velocity generated in the constant velocity joints 10 and 11 and the couplings 12 and 13 in the bath due to the penetration angle of the drive shafts 4 and 5 into the plating bath 3 is absorbed by the torque converters 16 and 17. The drive motors 6 and 7 and the support rolls 1 and 2 do not induce vibration due to angular velocity pulsation and prevent the occurrence of chatter marks on the surface of the plated steel strip due to the vibrations of the support rolls 1 and 2. To be done. In addition, support roll 1,
When the load of No. 2 changes, the torque converters 16 and 17
Automatically changes the driven shaft rotation speed in accordance with the fluctuation of the driven shaft torque and does not affect the driving shaft torque of the drive motors 6 and 7 so much that over-rotation of the drive motors 6 and 7 is prevented. Generation of chatter marks on the surface of the plated steel strip due to vibration of the support rolls 1 and 2 is suppressed.

Example 2 The apparatus of the present invention described in Example 1 was used, and the plate thickness was 0.8 m.
Under the conditions of a collecting roll pushing amount of 25 mm, a stabilizing roll offset amount of about 3 mm, and a line speed of 75 m / min, a steel strip to be plated having a width of m and a plate width of 1800 mm is passed through a hot dipping bath to form a steel strip. Manufactured. Then, the state of occurrence of chatter marks on the surface of the plated steel strip was investigated, but no chatter marks were found.

[0017]

As described above, according to the apparatus of the present invention, the cause of vibration of the roll in the hot dip plating bath can be absorbed and cut off by the fluid transmission device, and the plated steel strip caused by the vibration of the roll in the plating bath. The occurrence of chatter marks can be prevented or greatly reduced, and the surface quality of the plated steel strip can be greatly improved.

[Brief description of drawings]

FIG. 1 is an explanatory view of a vibration suppressing device for a roll in a plating bath according to the present invention.

FIG. 2 is an explanatory view of a general hot dip plating line.

FIG. 3 is an explanatory diagram of a drive system for a support roll of a general hot dip plating line.

4A and 4B are explanatory views of a 4-pin type cross pin, in which FIG. 4A is a structural explanatory view, and FIG. 4B is an explanatory view of I-axis and J-axis angles projected from the y-axis direction.

FIG. 5 is an angle diagram of I-axis and J-axis, where (a) is an angle diagram of ψ ₁ and ψ ₂ with θ ₁ as a variable, and (b) is ψ _i −θ.
It is an angle diagram of ₁ (i = 1, 2).

FIG. 6A is an angle diagram showing a relationship between an output shaft and a cross pin, and FIG. 6B is an angle diagram showing pulsation of angular velocity.

FIG. 7 is a diagram showing transmission characteristics from a motor side cross pin, a bath cross pin, and a drive motor to a bath roll.

FIG. 8 is a diagram showing a transfer characteristic from a drive motor to a bath roll when a fluid transmission device is used.

[Explanation of symbols]

 1, 2 Support rolls 3, 22 Plating baths 4, 5, 27, 28 Drive shafts 6, 7, 29 Drive motors 8, 9, 30 Reduction gears 10, 11, 31 Constant velocity joints 12, 13 Bath couplings 14, 15 Roll Shafts 16 and 17 Torque Converter 21 Steel Plated 23 Sink Roll 24 Collecting Roll 25 Stabilizing Roll 26 Wiping Nozzle

Claims (1)

[Claims] 1. A vibration suppressing device for a roll in a plating bath, wherein a fluid transmission device is provided between the roll in the plating bath of a hot dip coating line and a drive motor.