JP2659526B2 - Method for equalizing nip pressure in coater head of roll coater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for equalizing a nip pressure in a coater head of a roll coater in a continuous strip coating line.

[0002]

2. Description of the Related Art Conventionally, in a roll coater of a continuous strip coating line, a nip pressure between rolls is controlled by a left-right average control method or a left-right independent control method. In the nip pressure control by the above-mentioned left-right average value control method, if the difference between the set values of the nip pressure on the left and right sides of the roll and the detected value of the nip pressure during the operation is equal to or larger than an allowable value, the difference between the left and right deviations is allowed. It relies on manual operation by the operator to keep it within the value. Specifically, for example, of the left and right sides of the roll, the one in which each deviation between the detected value of the nip pressure and the set value is larger on the positive side is first monitored while monitoring the nip pressure detected value, and then retreated (opposed). Move away from the opponent's roll).

At this time, the nip pressure detection value on the other side is also reduced due to the influence of the retreat on one of the left and right rolls. Is obtained, and if necessary, the other side is advanced, for example. Under the influence of the forward movement, the forward / backward movement by the manual operation of either the left or right of the roll affects the other, so that the nip pressure detection value of one of the above also increases. Therefore, the difference between the nip pressure setting value and the nip pressure detection value on the left and right sides of the roll is made uniform by moving the roll forward and backward alternately. In the nip pressure control by the left and right independent control method, the roll left and right common or separate set values are provided,
The left and right roll forward and backward drive motors are controlled independently.

[0004]

In the above-mentioned average value control method, when the difference between the set value of the nip pressure on the right and left of the roll and the detected value of the nip pressure exceeds the allowable value, the difference is corrected to the allowable value. There is a problem that the operation when trying to do so is complicated, and the accuracy of correction and the required time are determined by the experience of the operator. On the other hand, in the left and right independent control method, the difference between each deviation of the nip pressure set value and the nip pressure detection value on the left and right of the roll does not basically exist constantly, but during normal nip pressure control, In the same manner as described above, since the movement of one side of the roll right and left affects the other side, the interaction between the nip pressure controls of the left and right rolls occurs, so it is difficult to increase the control gain, and the control accuracy is consequently reduced. descend. Also, if the nip pressure set value is low,
In particular, due to disturbances, for example, the reaction force due to the movement and expansion and contraction of the roll rotation drive transmission shaft, problems such as unstable nip pressure control and non-negligible imbalance of true left and right nip pressures occur. . The present invention has been made to solve such a conventional problem, and has made it possible to equalize the difference between the difference between the set value of the nip pressure on the right and left sides of the roll and the detected value of the nip pressure without relying on the experience of the operator. An object of the present invention is to provide a method for equalizing a nip pressure in a coater head of a roll coater.

[0005]

In order to solve the above-mentioned problems, the present invention obtains a difference between each detected value and a set value from a detected value of nip pressure on the right and left sides of the roll, and the difference is larger than an allowable value. In this case, the average pushing amount is obtained from the detected value based on the relationship between the roll pushing amount and the nip pressure obtained in advance, and the effective pressing force at the right and left end faces of the roll is obtained from the average pushing amount and the detected nip pressure values of the left and right rolls. While calculating the pushing amount, the required pushing amount is calculated from the set value of the nip pressure on the left and right sides of the roll, and the required change amount of the pushing amount on the left and right end faces of the roll is calculated from the difference between the effective pushing amount and the required pushing amount. The operation amount of the roll left / right drive motor is controlled based on the required change amount to move the operation target roll.

[0006]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an example of a coater head of a roll coater in a continuous strip application line to which a nip pressure control method according to the present invention is applied. In this coater head, a backup roll 11, an applicator roll 12, a transfer roll 13, and a pickup roll 14 are rotatably provided. The backup roll 11 is rotatably supported by the frame 15 at a fixed position, and the strip S is wound around the backup roll 11 and transported.

The applicator roll 12 facing the backup roll 11 is provided on the first receiving table 1 on the lower table 16.
7 rotatably supported. This lower table 16
Is provided so as to be able to advance and retreat by a hydraulic cylinder 18 fixed at a fixed position, that is, to be able to advance and retreat with respect to the backup roll 11. The first receiving table 17 is disposed on the lower table 16 so as to be able to advance and retreat, and two first driving units provided on both sides in the direction perpendicular to the paper surface, that is, on each of the left and right sides of the lower table 16 toward the frame 15. The motor 19, for example, a stepping motor is separately driven on the left and right via the first speed reducer 20. Further, a drive shaft that exits the first speed reducer 20, penetrates the upright portion of the lower table 16, and engages with the first receiving table 17 so as to convert rotational motion into linear motion is provided with a nip pressure detection First load cell 2
And a first stopper 2 on the surface of the upright portion facing the first cradle 17, which is a retreat limit of the first cradle 17.
2 are provided.

Accordingly, the applicator roll 12 is moved forward by independently driving the left and right sides toward the backup roll 11 and pressed against the strip S wound and conveyed by the backup roll 11 so that the applicator roll 12 is driven on the left and right drive shafts. The left and right sides of the applicator roll 12, that is, the drive side and the operation side, are independently controlled so that the nip reaction force of the left and right drive shafts is equal to the set value of the left and right nip pressures. In addition to being able to move forward and backward, the moving distance on each of the left and right advancing / retracting axes can be understood.

[0009] Similarly, the transfer roll 13 is
The pickup roll 14 is placed on the second receiving table 23 on the receiving table 17.
Is rotatably supported by a third receiving stand 24 on the second receiving stand 23. The second cradle 23 is disposed on the first cradle 17 and the third cradle 24 is disposed on the second cradle 23 so as to advance and retreat. Left and right are driven separately by 25 or two third drive motors 26 via a second speed reducer 27 or a third speed reducer 28. Further, as described above, the second load cell 29, the second stopper 30, and the third load cell 3 are provided for the transfer roll 13 and the pickup roll 14.
The first and third stoppers 32 are provided. Then, the transfer roll 13 and the pickup roll 14 are moved forward and backward,
In addition, the moving distance can be understood. The first receiving stand 17, the second receiving stand 23, and the third receiving stand 24 can be independently advanced and retracted in the direction perpendicular to the paper surface, that is, on the left and right sides. Further, the pickup roll 14 is immersed in the paint in the paint pan 33 below, and this paint adheres to the peripheral surface of the pickup roll 14 and
3. Transfer to the applicator roll 12 and apply to the strip S.

Next, in the coater head having the above configuration, a nip pressure control method according to the present invention applied to equalize the difference between the difference between the set value of the left and right nip pressures and the detected nip pressure between the rolls. Will be described with reference to the flowchart shown in FIG. In the case of the above coater head,
In the following method, the applicator roll 12 and the transfer roll 1 are disposed between the strip S wound around the backup roll 11 and being conveyed and the applicator roll 12.
3 and between the transfer roll 13 and the pickup roll 14 in order to equalize the difference between the deviations in the left and right nip pressures. The target role, that is, the operation target role to be moved is the role on the left side of the paired roles in FIG. Therefore, the strip S wound around the backup roll 11 and transported and the applicator roll 12
In this case, the applicator roll 12 is the roll to be operated.

FIG. 2 is a flowchart showing each step in the nip pressure control method.
In 1), the first, second, and third load cells 21, 29, 31
Among them, a force (hereinafter, referred to as a nip pressure) corresponding to the nip pressure on the right and left sides of the roll related to the nip pressure control is detected. In step 2 (S2), the deviation between the set value of the nip pressure and the detected value is calculated on each of the left and right sides of the roll, and the difference between the left and right deviations is calculated. Judgment is made, and when the value is equal to or more than the allowable value, the process proceeds to the next step, and in other cases, the equalization is ended. Step 3 (S
In 3), an average pushing amount corresponding to the total nip pressure of the detected values of the left and right rolls is obtained based on a table created in advance showing the relationship between the pushing amount of the roll and the nip pressure (total left and right nip pressures). Here, the pushing amount is a distance by which the operation target roll is pushed from the roll touch point, and the pushing amount is an amount by a movement command to a drive motor for moving the operation target roll back and forth after the roll touch (eg, clockwise). Or the integrated value of the number of pulses or digital numerical data with respect to counterclockwise rotation.

In step 4 (S4), an effective pushing amount is calculated based on the average pushing amount and the detected values of the nip pressure on the left and right sides of the roll. Here, the effective pushing amount refers to the pushing amount on the left and right end faces of the roll calculated on the basis of the detected nip pressure value. Specifically, first, as shown in FIG. 3, for example, the distance from both ends of the roll to the pressing action point is L _3, and the force corresponding to the nip pressure detected at the pressing action point on the left side of the roll is F ₁ (kg). ), Assuming that the force corresponding to the nip pressure detected at the pressing action point on the right side of the roll is F ₂ (kg), the left end of the roll at the center of gravity of the force corresponding to the same nip pressure as the nip pressure at this time. Distance L ₁ (m
m) is calculated by the following equation.

(Equation 1) Here, L ₀ : roll surface length (L ₁ + L ₂ )

Next, assuming that the characteristics (compression strain rate in the width direction) of the roll, that is, the rubber roll, are uniform and that the change in the nip pressure, which is the reaction force of the rubber, is proportional to the change in the indentation. Based on the position of the center of gravity of the reaction force of the roll corresponding to the position of the center of gravity of the nip pressure, the ratio of the effective pushing amount on the left and right end surfaces of the roll is calculated by the following equation.

(Equation 2) Note that the change in the nip pressure is actually proportional to the 1.5th power of the change in the pushing amount, but the change in the roll pushing amount when equalizing the left and right nip pressures is small. Even if it is considered that the amount of change in the nip pressure is proportional to the amount of change in the pushing amount, there is no practical problem.

Then, the effective pushing amount at the right and left end faces of the roll is calculated by the following equation from the average pushing amount which is an average value over the entire length of the roll obtained at step 3 and the ratio of the effective pushing amount at the right and left end faces of the roll. .

(Equation 3)

In step 5 (S5), the required pushing amount on the left and right end faces of the roll is calculated from the average pushing amount obtained in step 3 and the set values of the left and right rolls by the following equation. Here, the required pushing amount refers to the pushing amount required to realize the set value.

(Equation 4) However, “the pushing amount at the left end” in the equations (5) and (6)
The ratio of the "right edge of the pressing amount" is determined with reference to (2), L ₁ indicating the gravity center position, i.e. the nip圧重center position of the force in the equation (2), in (1) were detected It is determined using the left and right nip pressure set values instead of the forces F ₁ and F ₂ corresponding to the left and right nip pressures. Note that the ratio of the required pushing amount on the left and right end surfaces of the roll is calculated from the nip pressure center of gravity position calculated from the nip pressure setting values on the right and left sides of the roll in the same manner as in the case of the ratio of the effective pushing amount.

In step 6 (S6), the difference between the effective pushing amount at the left and right end faces of the roll and the required pushing amount at the left and right end faces of the roll, that is, the required change amount of the pushing amount at the right and left end faces of the roll is calculated. In step 7 (S7), the amount of movement at the pressing action point is calculated. First, to calculate the position of the roll assumes a fulcrum at the intersection of the roll center axis R ₂ (coordinates) in the case of the realized roll center axis R ₁ and demand pressing amount of roll right and left end faces of the moment. In particular,
As shown in FIG. 4, the position X of the assumed roll point of the roll, for example, the distance L ₁₁ (mm) from the left end of the roll, represents the required change amount of the pushing amount on the left end surface of the roll α ₁ , and the required change amount of the right end surface of the roll also If α ₂ is used, it is calculated by the following equation.

(Equation 5) In the case of the example shown in FIG. 4, since the right end of the R ₂ becomes below the right end of the R _1, alpha ₂ has a numerical value having a negative value. Then, the ratio of the distance from the assumed roll point to the end face of the roll and the distance from the assumed roll point to the point on the roll center axis at which the force for actually pushing the roll is applied is calculated.

Next, based on the necessary change amount of the pushing amount on the left and right end faces of the roll and the above ratio, the moving amount at the pushing action point for applying the pushing force on the roll center axis is calculated by the following equation. calculate.

(Equation 6) In step 8 (S8), the amount of the movement command corresponding to the movement amount, for example, the number of pulses given to the left and right stepping motors is calculated, and the movement command indicating the calculated amount, for example, calculated for the left and right stepping motors. A pulse signal of the set number of pulses is output, and each stepping motor is driven to move the roll. In step 9 (S9), the nip pressure on the left and right sides of the roll is detected. Step 10 (S10)
In each of the left and right sides of the roll, the deviation between the set value of the nip pressure and the detected value is calculated, the difference between the left and right deviations is calculated, and it is determined whether or not this difference is equal to or greater than an allowable value. In the above case, the process returns to step 4, and in other cases, the equalization ends.

[0018]

As is apparent from the above description, according to the present invention, the difference between the detected value and the set value is obtained from the detected values of the nip pressures on the right and left sides of the roll. In addition to calculating the average pressing amount from the detected value based on the relationship between the pressing amount of the roll and the nip pressure obtained in advance, the effective pressing on the right and left end faces of the roll from the average pressing amount and the detected values of the nip pressure on the left and right of the roll. On the other hand, the required pushing amount is calculated from the set value of the nip pressure on the left and right sides of the roll, and the required change amount of the pushing amount on the left and right end faces of the roll is calculated from the difference between the effective pushing amount and the required pushing amount. The operation amount of the left and right drive motors is controlled on the basis of the required change amount to move the roll to be operated.

For this reason, the nip pressure control for the right and left rolls (uniformity of the difference between the set value of the nip pressure for the right and left rolls and the detected value of the nip pressure) is automated, and the nip pressure for the right and left nips can be controlled without relying on the experience of the operator. The above-described control of the pressure becomes possible, and the nip pressure control is simplified and speeded up. In addition, since the control content takes into account the interaction of the change in the nip pressure between the right and left sides of the roll, it is related to the original nip pressure control. This has the effect of making it possible to equalize the nip pressure on the left and right sides of the roll without impairing the control gain and control accuracy.

[Brief description of the drawings]

FIG. 1 is a view schematically showing an example of a coating machine to which a nip pressure control method according to the present invention is applied.

FIG. 2 is a flowchart showing each step in a nip pressure control method according to the present invention.

FIG. 3 is a diagram for explaining calculation of a nip pressure gravity center position from nip pressures on the right and left sides of a roll.

FIG. 4 is a diagram for explaining calculation of a movement amount at a roll pressing action point.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 Backup roll 12 Applicator roll 13 Transfer roll 14 Pickup roll 17 1st receiving stand 19 1st stepping motor 20 1st reduction gear 21 1st load cell 22 1st stopper 23 2nd receiving stand 24 3rd receiving stand 25 2nd stepping Motor 26 Third stepping motor 27 Second speed reducer 28 Third speed reducer 29 Second load cell 30 Second stopper 31 Third load cell 32 Third stopper S Strip

Claims (1)

(57) [Claims] 1. A difference between each deviation between a detected value and a set value is determined from a detected value of a nip pressure on the right and left sides of a roll, and when the difference is equal to or larger than an allowable value, a difference between a previously determined roll pushing amount and a nip pressure is determined. Based on the relationship, the average pushing amount is obtained from the detected value, and the effective pushing amount at the right and left end faces of the roll is calculated from the average pushing amount and the nip pressure detected values at the right and left sides of the roll. Calculate the pushing amount, calculate the required change amount of the pushing amount on the left and right end faces of the roll from the difference between the effective pushing amount and the required pushing amount, and calculate the operating amount of the roll left and right drive motor based on the necessary changing amount of the pushing amount. A method for equalizing the nip pressure in a coater head of a roll coater in which a controlled roll is moved under control.