JP3231750B2 - Driving structure of roll in hot-dip bath - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for driving a roll in a bath immersed in a metal bath in a continuous hot-dip galvanizing line for galvanizing or the like.

[0002]

2. Description of the Related Art A continuous hot-dip galvanizing line for continuously galvanizing long steel sheets includes a plating bath (pot) 1 as shown in FIG. 3, a sink roll 4 and a stabilizing roll 5.6. Rolls are used in the bath. The pot 1 is a container for storing molten zinc, and the rolls 4 to 6 in the bath are cylindrical rolls for guiding and supporting the steel sheet x. Upstream reel (not shown)
The steel sheet x sent out of the furnace is subjected to a heat treatment while removing and reducing an oxide film in the immediately preceding annealing furnace 3, and then passed through a zinc bath 2 in a pot 1 through a sink roll 4 as shown in FIG. A zinc coating is applied. The plating thickness is adjusted by blowing air from an air knife (not shown) on the steel sheet x while supporting and pulling it up with the stabilizing rolls 5 and 6. Thereafter, the steel sheet x is cooled and taken up on a downstream reel (not shown).

The in-bath rolls 4 to 6 may be configured to rotate with contact with the steel plate x, or may be arranged to be driven by a drive source such as a motor. For the stabilizing rolls 5 and 6, which are difficult to rotate because the winding angle of the steel sheet x is small, the latter, that is, some drive structure is often provided.

FIGS. 4 (a) and 4 (b) show a conventional structure for driving a roll in a bath. First, FIG. 4 (a) shows an example described in Japanese Utility Model Publication No. 60-38668, in which a motor 31 and the like are installed on a support frame 10 for supporting and elevating the roll 6 in a bath. The transmission chain 32 connects between them. Chain 3
A portion of the coating 2 that comes out above the zinc bath 2 is covered with a heat insulating cover 33, and is heated using a gas burner 34 to prevent solidification of zinc attached to the chain 32. On the other hand, FIG. 4B shows the transmission shaft 35 arranged obliquely.
This is an example in which the in-bath roll 6 is connected to a motor 38 or the like via a. The drive source including the motor 38 is provided at a position higher than the upper end of the bathtub 1, and the roll 6 immersed in the zinc bath 2 and the drive source are connected by the transmission shaft 35. Since the output shaft of the drive source and the roll 6 are horizontal while the transmission shaft 35 is inclined, universal joints 36 and 37 are provided at the connection between the shafts.

[0005]

The driving structure shown in FIG. 4A has the following problems. That is, a) the service life of the transmission chain 32 (and the sprocket meshing therewith) is not long. The chain 32
(And sprockets) are immersed in the hot zinc bath 2.

(B) Impurities (called “dross”) floating on the bath surface 2 a of the zinc bath 2 are caught in the bath by the chain 32. When the suspended matter enters the bath, it adheres to the surface of the steel sheet x and deteriorates the quality of the plating layer. As for the part where the steel sheet itself enters the bath, as shown in FIG. 3, a part of the annealing furnace 3 surrounds the bath surface 2a to keep the atmosphere free of dross. Considering that the dross is kept away from the steel plate by the action of the air coming out of the bath, the dross must be originally prevented from being caught in the bath by the chain 32 of FIG.

On the other hand, there is also a problem when using the drive structure shown in FIG. For example, c) it is difficult to drive the in-bath roll 6 at a constant speed without fluctuation. Since one of the universal joints 36 and 37 (joint 36) is immersed in the zinc bath together with the roll 6, the structure must be simple (therefore, there is generally considerable backlash). This is because it is not possible to provide high-grade functions that can be transmitted. When the rotation speed of the roll 6 fluctuates, there are disadvantages that the steel plate vibrates or the plating thickness becomes uneven.

[0008] d) The rotation speed of the roll 6 cannot follow minute fluctuations in the feed speed of the steel sheet. This is because the roll 6 is connected to the drive source via the transmission shaft 35 and the like, and is not rotated by the contacting steel plate. In such a case, slip occurs between the roll 6 having the speed difference and the steel plate, and the surface of the steel plate is easily damaged.

E) Equipment costs are high. Since it is necessary to transmit a smooth rotational force to the roll 6 and the inclination angle of the transmission shaft 35 cannot be increased so much, the transmission shaft 35 must be lengthened, and the position of the drive source, the shape of the pot 1, This is because special consideration is required for depth.

F) Maintenance of the roll 6 in the bath cannot be easily performed. Because the roll 6 is connected to the drive source via the transmission shaft 35, when the roll 6 is pulled out of the bath for maintenance, it is necessary to move the drive source at the same time, which complicates complicated and cumbersome work. .

The present invention solves the above-mentioned problems in the case of plating a material to be plated such as a steel plate with a molten metal such as zinc, and involves dross on a bath surface or uneven rotation speed. The purpose of the present invention is to provide a structure for driving a roll in a bath, which does not occur.

[0012]

According to the first aspect of the present invention, there is provided a driving mechanism for a roll in a bath, which is configured to rotate a roll in a bath immersed in a metal bath for hot-dip plating. A stator that generates a rotating magnetic field is provided on a part of the support frame of the roll.b) Rotation without a slip ring that generates a rotating torque near the shaft end of the roll in the bath due to the action of the rotating magnetic field by the stator. The feature is that the child is integrated. In the stator of the above a), a portion to be prevented from contacting the metal bath, such as a winding (coil) portion, is hermetically sealed inside the casing. By using a conductor, a magnetic pole, or a magnetic material as the rotor in b), a rotor without a slip ring can be configured as described above.

In the drive structure according to the first aspect of the present invention, the combination of the stator a) and the rotor b) causes the rotor to generate rotational torque on the same principle as that of the electric motor. That is, when a conductor is used in the rotor of b), a drive structure imitating a squirrel-cage induction motor is configured by a combination with the stator of a) provided on a part of the support frame,
An electromagnetic force is generated by the rotating magnetic field and the eddy current generated in the rotor based on the induced electromotive force, and as a result, a torque is generated in the rotor. When a magnetic pole or a magnetic body is used as the rotor in b), a synchronous motor is substantially constituted by the combination with the stator in a), and the rotor is pulled by the magnetic pole of the rotating magnetic field, and Torque is generated. Since the rotor is integrated with the roll in the bath,
If an appropriate amount of torque is continuously generated in the rotor, the roll in the bath will rotate stably.

That is, the roll in the bath is of the conventional type (FIG. 4 (a)).
・ Refer to (b)), although it is not connected to an external drive source via a chain or a transmission shaft, it rotates by the action of a rotating magnetic field or the like to guide a material to be plated (a steel plate or the like). Provide support. For this reason, the above driving structure has the following merits.

Since a chain and a transmission shaft are not required, the structure and layout of the pots and the like for arranging them are not complicated, and the maintenance associated with their consumption in the bath is unnecessary, and they have them. The rotation speed does not fluctuate due to backlash or the like.-Since the moment of inertia (GD ² ) of the roll in the bath is small based on the lack of mechanical connection with the driving source, the feed speed of the material to be plated is very small. When the roll changes, the roll easily follows the change, so it is difficult to damage the surface of the material to be plated. ・ Since there is no mechanical connection with the drive source, etc.
It is easy to pull up the roll in the bath, so it is easy to perform maintenance such as inspection and maintenance of the roll. ・ Since there is no need to use parts that cross the bath surface and go in and out of the bath like chains, There is no danger of dross on the bath surface getting caught in the bath. ・ Since the rotor does not have a slip ring, there are no parts to be consumed in the bath for a short period of time, and therefore, the frequency of maintenance is reduced.

A driving structure according to a second aspect is characterized in that a hysteresis ring is used as the rotor. The hysteresis ring refers to an annular body made of a magnetic material, and is specifically made of a material having a large hysteresis loss, such as magnet steel or cobalt steel.

When a hysteresis ring as a rotor is used in combination with the above-described stator, a hysteresis motor which is a kind of a synchronous motor is substantially constituted. Therefore, this drive structure has many advantages based on the characteristics of the hysteresis motor in addition to the advantages described above. They are very suitable for driving the roll in the bath so as not to rub against the material to be plated, as follows.

Smooth rotation, small vibration and uneven speed, small change in torque, easy starting, high efficiency.

The drive structure according to the third aspect further includes a power supply device for supplying a variable frequency power supply to the stator, and means for detecting the rotation speed of the roll in the bath. The power supply device is provided with a control circuit for issuing a frequency instruction signal after comparing the rotational speed detected by the means with the rotational speed.

In this drive structure, first, by supplying variable frequency power from the power supply device to the above-mentioned stator, the rotation speed of the rotating magnetic field by the stator can be appropriately changed. If the rotation speed of the rotating magnetic field is changed, the rotation speed of the rotor is changed, and the rotation speed of the roll in the bath is also changed. In this drive structure, the rotation speed of the roll in the bath is detected by the detection means, and the detected rotation speed is compared with the set rotation speed by the control circuit. So that the deviation is zero)
The control circuit operates the power supply as described above. Therefore, by controlling the so-called closed loop, the rotation speed of the roll in the bath can be appropriately controlled.

According to a fourth aspect of the present invention, in the drive structure, a setting device for determining the set rotation speed by inputting the diameter of the roll in the bath and the actual feed speed of the material to be plated is further arranged. Features. However, the diameter of the roll in the bath is
Enter the actual measurement value at the time when the roll is actually used, such as the dimensions at the time of manufacturing the roll and the dimensions at the time of grinding the surface during subsequent maintenance. The actual feed speed of the material to be plated is obtained by real-time measurement (including a value converted from the rotation speed of pinch rolls or the like) at a position close to the roll in the bath during the execution of continuous hot-dip plating. The speed of the material to be plated is input.

When the setting device determines the set rotation speed based on the diameter of the roll in the bath and the actual feed speed of the material to be plated as described above, the roll in the bath adjusts the speed of the material to be plated during operation. The rotation speed is controlled to an appropriate and preferable rotation speed.
This is because the value obtained by dividing the actual feed speed of the material to be plated by the actual diameter of the bath roll corresponds to the optimum rotation speed of the bath roll at that time.

According to a fifth aspect of the present invention, in the structure of the first or second aspect, an electric pulse corresponding to a set rotation speed is input as a stator, and the magnetic field is rotated stepwise by a predetermined angle. On the other hand, a gear-shaped rotor having a plurality of radial projections (magnetic poles or salient pole cores) is used as the rotor.

When such a stator and a rotor are used in combination, a driving structure imitating a so-called stepping motor is formed. That is, the rotation of the rotor in small steps at an accurate fixed angle is caused by the rotation of the step-like magnetic field in the stator and the above-described protrusion of the rotor. Therefore, in this drive structure, the rotation speed of the roll in the bath can be appropriately controlled by controlling the so-called open loop in which the rotation speed is not detected by adjusting the number of inputs per unit time of the electric pulse.

[0025]

1 and 2 show an embodiment of the present invention. FIG. 1A is a front view showing a plating bath (pot) 1 in a continuous hot-dip galvanizing line for steel sheets shown in FIG. 3, a roll 6 in the bath, a driving structure 10 thereof, and the like. FIG. 1B is a sectional view taken along line bb in FIG. FIG. 2 is a schematic diagram showing a driving structure 10 of the in-bath roll 6 and related devices. The in-bath roll 6 exemplified here corresponds to the stabilizing roll 6 (or 5) shown in FIG. 3, but the sink roll 4 in FIG. 6 can also be configured.

As shown in FIG. 1, the in-bath roll 6 is rotatably supported by a support frame 7 at shaft portions 6a near both ends. Reference numeral 7a denotes a bearing fitted to the shaft portion 6a, which is mounted in a cylindrical shape using an alloy having high heat resistance, erosion resistance and solid lubricity.
The roll 6 is lifted up from the zinc bath 2 together with the frame 7 for maintenance or the like. However, when immersed in the bath, the roll 6 is accurately lowered to the fixed position shown in FIG. x direction perpendicular to the longitudinal direction). The in-bath roll 6 and the frame 7 are made of a stainless-based metal that is not easily melted in the zinc bath 2 at a high temperature (460 to 600 ° C.).

The in-bath roll 6 is periodically pulled up from the zinc bath 2 to check its surface condition and the like, and is appropriately ground to prevent its surface from becoming rough. However, if the feed speed of the steel sheet x and the peripheral speed of the roll 6 do not match, the surface of the steel sheet x may be scratched by rubbing against the surface of the roll 6. A drive structure 10 is additionally provided.

As the driving structure 10, first, the sub-frame 12 is extended downward from the upper portion of the support frame 7,
A stator 11 for generating a rotating magnetic field is provided inside the sub-frame 12. Although not shown in detail, the stator 11 is formed by stacking silicon steel plates and winding them, and they are fixed inside a casing 12 a integral with the subframe 12. As shown in FIG. 1B, a power supply cable 21a for supplying power from the power supply device 21 to the windings of the stator 11 is also disposed inside the casing 12a. Since the casing 12a is of a type that seals the inside, there is no possibility that the stator 11 and the power supply cable 21a come into contact with the zinc bath 2. The service life of the silicon steel sheet in the stator 11 does not become extremely short even when it comes into contact with the zinc bath 2 (the steel sheet may be appropriately coated to extend the service life). It is also possible to make the peripheral surface (inwardly facing surface) protrude inside the casing 12a. In this example, the subframe 12 and the stator 11 are provided only at positions adjacent to the support frame 7, but they may be provided near the other bearing (not shown).

As another important part of the drive structure 10, a rotor 16 is mounted on the shaft 6a of the roll 6 in the bath. As the rotor 16, an annular body made of a magnetic material (cobalt steel) called a hysteresis ring or the like is used.
It is fixed on the shaft portion 6a while being fitted to the outside of the inner ring 17 which is a non-magnetic material. When the roll 6 is supported on the frame 7 via the bearing 7a, the rotor 16
And the positional relationship is determined so that a gap is formed between the inner peripheral surface of the casing 12 a and the outer peripheral surface of the rotor 16.

Stator 11 fixed to sub-frame 12
When a three-phase AC power supply is connected via a power supply device 21, a rotating magnetic field is generated in the stator 11 and is attracted to the rotating magnetic field by the same principle as that of a general hysteresis motor, and the rotor (hysteresis ring) 16 is torqued. Receive. The torque received by the rotor 16 is transmitted through the inner ring 17 to the shaft 6.
a, so that the roll 6 rotates in the bath. Moreover, the rotation is smooth based on the characteristics of the hysteresis motor, and the energy efficiency is excellent.

The drive structure 10 is connected to devices as shown in FIG. 2 for performing speed control and the like. That is, as described above, the power supply device 21 and the power supply cable 21
a, the driving structure 10 is connected to a three-phase AC power supply, a rotation speed detecting means 22 is disposed for the roll 6 in the bath, and a control circuit 23 is connected to the power supply 21 and the speed detecting means 22. Connected. The power supply device 21 has a frequency control function incorporating a transistor inverter and the like.
The control circuit 23 is a unit that outputs a frequency setting signal to the power supply device 21. As shown in FIG. 2, a setting device 24 is also connected to the control circuit 23. In this setting device 24, the diameter of the roll 6 (recent measured value) is input in advance, and the line speed (steel plate) The actual rotation speed of the roll 6 (set rotation speed) is calculated according to both data, and output to the control circuit 23 every hour. The control circuit 23 receives the set rotation speed output from the setter 24 and the actual rotation speed of the roll 6 output from the detection means 22 and outputs a frequency setting signal based on a comparison result (control deviation) of the two. Output to the power supply 21. The detecting means 2
2 may be mounted on a support frame 7 as shown in FIG. 1A, for example, to pick up the rotation of a detection target 6b provided in a part of the shaft 6a.

When the frequency of the AC power supplied to the driving structure 10 is converted by the power supply device 21, the moving speed of the rotating magnetic field in the stator 11 (FIG. 1) of the driving structure 10 is changed.
Thus, the rotation speed of the roll 6 in the bath is also changed. In the control system of FIG. 2, since the closed loop automatic control using the detection means 22 and the control circuit 23 is performed as described above, the in-bath roll 6 can be driven at a suitable rotation speed corresponding to the line speed.

Since the in-bath roll 6 is in contact with the bearing 7a and the steel plate x and is not mechanically connected to any other object, the rotation speed is easily changed by a slight external force. Therefore, even if the speed of the steel sheet x fluctuates minutely, it easily follows the speed, and in that sense, rubbing with the steel sheet x hardly occurs.

When the in-bath roll 6 is lifted from the zinc bath 2, it is desirable that the in-bath roll 6 be easily removed from the support frame 7 in order to perform various maintenance such as surface grinding. From such a viewpoint, the support frame 7
(The portion below the center of the bearing 7a) and the tip of the sub-frame 12 (the portion below the center of the stator 11) can be separated from each other, or the support frame 7 on one side can be separated. It is preferable to be able to slide in the axial direction of the roll 6.

In addition, in the example of FIGS.
Although a configuration imitating a hysteresis motor was taken as 0,
This does not mean that other configurations cannot be adopted. For example, by providing a conductor (copper or the like) that easily generates an induced eddy current as the rotor 16 or arranging a magnetic pole of a permanent magnet that is easily pulled by a rotating magnetic field, a cage-type induction motor or a synchronous motor is modeled, respectively. The driving structure thus configured is configured. In addition, by using a combination of a stator that receives an electric pulse corresponding to a set rotation speed and rotates a magnetic field in a stepwise manner at a fixed angle and a gear-shaped rotor having a plurality of radial protrusions, so-called stepping is performed. It is also possible to configure a drive structure imitating a motor. In the latter case, the rotation speed of the roll in the bath can be controlled by simple open-loop control based on the number of input electric pulses.

In the above, the roll in the bath immersed in a hot-dip zinc bath for galvanizing has been described. However, in order to perform plating of tin (tin) or aluminum instead of galvanizing, hot-dip tin or molten aluminum is used. Of course, it is also possible to implement the invention as a drive structure of a roll in a bath immersed in a metal bath such as described above.

[0037]

According to the driving mechanism of the in-bath roll described in the first aspect, the in-bath roll rotates by the action of a rotating magnetic field or the like without being mechanically connected to an external driving source to guide the material to be plated. And support, the following effects are obtained.

It is not necessary to dispose a power transmission chain or a transmission shaft, so that the structure and layout of the pots and the like can be simplified, the maintenance burden on them can be reduced, and the rotational speed fluctuation caused by them can be reduced.・ Since the moment of inertia of the roll in the bath is reduced, the roll can easily follow the fluctuation of the feed speed of the material to be plated.
The occurrence of scratches on the surface of the material to be plated is reduced.- It is easy to pull up the roll in the bath, so that maintenance such as inspection and maintenance of the roll can be easily performed.- Dross on the bath surface due to chains etc. There is no danger of getting caught in the bath. ・ Maintenance is less frequent because slip rings that wear out in the bath for a short period of time are not included.

The driving structure according to the second aspect has the following effects based on the characteristic of the substantially constituted hysteresis motor, and is preferable for driving the roll in the bath.

Smooth rotation, small vibration and uneven speed, little change in torque, easy start-up, high efficiency.

According to the drive structure of the third aspect, the rotation speed of the roll in the bath is appropriately controlled by controlling the so-called closed loop.

According to the drive structure of the fourth aspect, the roll in the bath is further controlled at a preferable rotation speed appropriately corresponding to the speed of the material to be plated during operation.

In the drive structure according to the fifth aspect, the rotation speed of the roll in the bath is appropriately controlled by simple open loop control without detecting the rotation speed.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of the present invention;
FIG. 1A is a front view showing a plating bath (pot) 1, a roll 6 in the bath, a driving structure 10 thereof, and the like in the continuous galvanizing line for the steel sheet x shown in FIG.
FIG. 1B is a cross-sectional view taken along the line bb in FIG. In FIG. 1A, the plating bath 1 and the like are cut along a vertical plane along the roll 6 in the bath.

FIG. 2 is a schematic view showing a driving structure 10 of a roll 6 in a bath and related devices.

FIG. 3 is a side view schematically showing a plating bath 1 and rolls 4, 5, 6 in a bath in a continuous hot-dip galvanizing line, as viewed from a direction different by 90 ° from FIG. .

FIGS. 4 (a) and 4 (b) are front views each showing a drive mechanism of a conventionally used in-bath roll.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plating bath 2 Zinc bath (metal bath) 4.5.6 Roll in bath 10 Driving structure 11 Stator 16 Rotor 21 Power supply device 22 Rotation speed detecting means 23 Control circuit 24 Setting device x Steel plate

Claims (5)

(57) [Claims] A structure for rotating a roll in a bath immersed in a metal bath for hot-dip plating, wherein a stator for generating a rotating magnetic field is provided in a part of a support frame of the roll in the bath. And a rotor not provided with a slip ring, which generates a rotating torque by the action of a rotating magnetic field generated by the stator, is integrated in the vicinity of the shaft end of the bath roll. Construction. 2. The hot-dip bath roll drive structure according to claim 1, wherein the rotor is a hysteresis ring. 3. A power supply unit for supplying a variable frequency power supply to the stator, and means for detecting a rotation speed of the roll in the bath, and comparing the set rotation speed with the rotation speed detected by the detection means. 3. The drive structure for a roll in a bath for hot-dip plating according to claim 1, further comprising a control circuit for issuing a frequency instruction signal to the power supply device. 4. The hot-dip plating according to claim 3, further comprising a setting device that determines the set rotation speed by inputting the diameter of the roll in the bath and the actual feed speed of the material to be plated. Driving structure of roll in bath. 5. A stator in which an electric pulse corresponding to a set rotation speed is input to rotate a magnetic field in a stepwise manner at a fixed angle, and the rotor is a gear having a plurality of radial projections. The drive structure of a roll in a bath for hot-dip plating according to claim 1 or 2, wherein: