KR20110046154A - Roll mill - Google Patents

Abstract

PURPOSE: A roll mill is provided to control a distance between rolls by full automatic control by solving various defects caused by displacement control and load control and to improve dispersing quality. CONSTITUTION: A roll mill includes a fixation roll and a movable roll. The movable roll is installed at a right angle to the roll by a servomotor and a ball screw. A laser sensor measuring the distance of the fixation roll and the movable roll is installed and a load sensor(10) measuring the press pressure between rolls is installed. An electrically automatic control device is equipped, wherein the electrically automatic control device manages constant distance of rolls with constant press pressure through feedback of detecting signal caused from the sensor.

Description

Roll Mill {ROLL MILL}

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a roll mill for use in wet dispersion, and more specifically, in the manufacturing process of various products such as ink, paint, ceramics, chemicals, foodstuffs, electronic materials and the like, fine powder, nanoparticles and the like in the treated material. A roll mill used for kneading and dispersing a substance of

An apparatus for kneading and dispersing materials such as fine powder and nanoparticles in a treatment material, comprising: a plurality of rolls having different rotational speeds, for example, three rolls in parallel in a transverse direction of three rolls; Dog roll mills are widely used. In this roll mill, for example, as disclosed in Japanese Utility Model Laid-Open No. Hei 1-83438, the load acting between the rolls is detected by a load sensor (load cell), and the front and rear rolls are held by a manual handle. The distance between rolls is adjusted by moving. In place of such a handwheel, only attempts to automatically control by a servo motor or the like cause various problems as described below, and it is difficult to accurately and automatically control only by load control by a load sensor.

Generally, as shown in FIG. 1, the roll mill for kneading | mixing and disperse | distributing a processing material is provided with the back roll and the front roll so that a movement to a mount (frame) is possible, and each roll has a roll axis at both ends, and a roll A bearing (not shown) is mounted to the shaft, and press pressure is applied through the bearing. The bearing of the roll shaft of the middle roll positioned between the after roll and the before roll is fixed to the mount. Therefore, "press pressure b" exists on the press-side roll contact line of both rolls, and "reaction force a" is generated on the fixed side roll contact line. As shown in Fig. 2, the press pressures (contact reaction forces) are crowns (R1, R2) on the surface of the roll so that the contact pressure is not a curve such as c or d but a constant value distribution (one flat line). Is formed. In addition, the press-side roll and the stationary-side roll are rotated at different rotational speeds, and are driven so as to generate a frictional force between the two rolls, and this frictional force is also responsible for one end of the dispersion effect.

The press pressure (or reaction force) and the crown on the roll surface are in a subtle relationship with any correlation, which must be theoretically related in exactly one cause and effect. Moreover, the frictional force applied between both rolls affects this press pressure (or reaction force), and it is judged that the influence is a thing which cannot be ignored as a change of press pressure. In other words,

(Extrapolation press pressure; P1, P2) = (contact linear press pressure) + (variation generated from frictional force)

The extrapolation press pressure does not become the press pressure on the contact line as it is.

Basically, about these phenomena, a finite element analysis model of a combination of two rollers in contact with each other is created, and a non-linear analysis in which the contact portion expands while the load is temporarily increased on the contact line is performed. Press pressure (P1) from, the press pressure (P2) from the previous roll, the crown (R1) of the after roll, the crown (R2) of the middle roll, the crown (R3) of the before roll, and the distance between the after roll and the middle roll ( δ1), the relationship between the distance δ2 of the middle roll and the previous roll is obtained specifically.

In addition, as for the friction between the rolls, as mentioned above, it is known that if there is a friction, it is involved as a variation and attracts the required "press pressure" to the side which is not applied. Therefore, the press pressure and the distance between the rolls of the rolls may maintain the relationship between P1, P2, δ1, and δ2 when there is no friction. Therefore, it is understood that δ1 and δ2 may be used as an index of control except for P1 and P2. Therefore, what is necessary is just to perform the control operation of a roll mill so that displacement control, ie, the distance between rolls δ1 and δ2 determined at the start of processing, may be maintained.

In more detail, there is a certain roll size for the roll mill, and in addition, there is a press pressure in the dispersion processing required by the user. Using these, the static analysis of a roll is performed once. From this result, it is known what the curved shape of the crown added to the roll and the curved peak value (usually in the center) become. Next, this analysis result is input, and it changes into the roll analysis model which added the crown. Two models are used as contact analysis models in which only the center crown peak part is contacted from the beginning. The finite element method nonlinear contact analysis is carried out according to the load increment method at a procedure in which one roll is used as a fixed roll to support both ends of the roll, and the same load is applied again from both ends of one roll. Thus, the load is subdivided into individual steps and finally reaches P1 or P2. This result is a shape as in the " constant reaction force " From this result, a distribution having a constant press pressure (or reaction force) is obtained on the contact line, and R1, R2, R3, P1, P2, δ1, and δ2 are obtained as correlation values at this time. Among these, R1, R2, and R3 are used as the crown amounts in roll design, and the remaining P1, P2, δ1, and δ2 are numerical values used for automatic control.

As described above, the automatic control of the roll mill is basically preferred to detect the position of the roll by the sensor and to control the displacement. However, the displacement control alone has the following problems. There is a need. First, the following nonconformity arises by unbalance of the load in the left and right ends of a roll. As shown in FIG. 3, the contact line pressure of a roll and a roll is a flat distributed load mostly in the place where the roll shape and the balance | balance of the roll added to the roll are balanced. However, in practice, when A and B are the roll point and C is the center point in FIG. 3, AC = L2 and CB = L1, the distributed load becomes larger at the center point C of AB / 2 = L1 = L2. It is.

In addition, since it is easy to switch this distributed load to the concentrated load in C, and to judge it, it is judged that the concentrated load P2 (P1) acts here. Then, it turns out that moment (P2 * L1, P2 * L2) acts on both sides of point C on a roll. However, the contact line pressure distribution may be inclined as shown in the lowermost part of the drawing due to some disturbance. At this time, the position of P2 is shifted | deviated from the center point C, for example, it may become L1> L2 (of course L2> L1 may exist). At this time, if the load is controlled, the total P2 is not changed, and as a result, the moment becomes P2 × L1> P2 × L2, and a moment difference between the left and right occurs. If so, P2 is tensioned on the L1 side (B side) for the moment difference, i. In addition, when reversed, it is stretched to the A side. Thereby, the force which always tries to stay in the center point C acts on P2, and is equipped with what is called self-alignment force.

By the way, when it completes as feedback control only for displacement control, the said self-alignment force becomes a mechanism which does not work. Specifically, according to the displacement control, the unbalance of the loads at the left and right ends of the rolls will also be corrected. However, if the driving is actually performed, the displacement control alone is subtle as the load even if a subtle unbalance occurs at both ends of the rolls. Unbalance is often detected.

In addition, considering the "relationship between the load and the displacement" during the actual operation and the "relationship between the load and the displacement" during the static load, as described above, when the press pressure P2 (P1) is applied to the roll As shown in FIG. 4, the natural contact portion is a circle that is somewhat crushed when viewed in cross section. That is, in FIG. 4, when the radius of a roll is set to R and the distance between roll axes is set to D, it becomes 2R> D. When the crushing margin at this time is 2R-D = 2d, it can be said that d is crushing margin in one roll. The distance between the rolls δ1 (δ2) at this time is controlled as D.

If so, when the material is injected, ask whether the actual displacement displacement control operation is started as the distance between the roll axes (D). Otherwise, "D + e" considering the clearance (e) into which the material is fitted is the actual value of the displacement control. Driving as. Therefore, it is necessary to adjust whether or not the load is consistent with P2 (P1) statically determined during the displacement control operation during operation, and at this time, the monitoring value of the load cell is detected to match the P2 (P1) "D +. It is necessary to drive at e ". In this case, therefore, the distance between the rolls δ1 (δ2) is controlled as D + e.

In roll mills, this "e" is generally referred to as a nip, and the nip on the material input side (first clearance) is specifically called a feed nip, and the scraping side (second clearance) The nip of is referred to as an apron nip, but in the present specification, both are collectively referred to as nips.

In addition, since the processing material is sandwiched between the rolls during kneading and dispersing, the initial film thickness of the processing material passing through the nip becomes the film thickness e as in the clearance e, but the film thickness e is kneaded and dispersed. It is known to decrease as it progresses. When this temporal change in the film thickness e is empirically grasped as a function of time [e (t)], the e is programmed so that the distance between the rolls δ1 (δ2) is controlled as D + e (t). do.

In addition, it is well-known that when the processing material is put into three roll mills, there exists a tendency for the viscosity of a material to fall as dispersion progresses, depending on the material original property. If it is assumed that this machine is used by circulating a plurality of passes, if only "displacement control" is maintained due to the viscosity decrease, the load applied to the material each time the pass is repeated may be reduced. Currently, there are many examples in the industry where three roll mills are used after passing many times. In such a case, when a load cell (load) monitor is required, and the viscosity decrease of the material is remarkable to a certain width, a mechanism that executes the correction on the program without performing any work from the outside does not require the user to achieve the desired dispersion. This is achieved by the dispersion treatment of the process. Thus, although operation control is displacement control, the mechanism which monitors a load with a load cell (load sensor), and adjusts the change by a program is provided.

There is also a problem when an abnormal load occurs. If the three roll mills are accidentally mixed with larger objects between the rolls during operation, only "displacement control" means that the control mechanism tries to maintain the displacement, causing huge loads and consequently impairing the machine's function. It is also assumed. In order to cope with this, a program for inserting a press pressure measuring load cell (load sensor) into the control system and avoiding huge loads by fast feedback at the moment when a sudden sudden displacement cannot be avoided can be avoided. This becomes possible. The load cell is also effective when so-called "overload protection safety measures" are included in the system. In addition, as described above, there may be a case where a huge displacement difference occurs due to nonuniformity of a certain remarkable viscosity, uneven distribution of the processing material on a roll, etc. in addition to the abnormal case in which an object larger than usual is inserted. In addition, in cases where these occur continuously, the time efficiency of the control that converges this difference is found to be somewhat inferior to the displacement control.

Therefore, in order to avoid this redundancy and make quick control, it is not enough to make an emergency stop but it is a program that temporarily switches displacement control to load control when a large disturbance occurs. It is more preferable to set the program to return to.

SUMMARY OF THE INVENTION An object of the present invention is to provide a roll mill which solves the above-mentioned deficiencies caused by the displacement control and the load control to improve the dispersion quality by controlling the distance between rolls by the automatic control.

According to the present invention, in a roll mill used for kneading and dispersing a substance such as fine powder and nano particles in a treatment material, the fixed roll fixed to the temporary object and the fixed roll provided in such a manner as to be able to contact / separate the fixed roll. It has a moving roll, this movement roll is installed so that a micro movement is possible in the perpendicular direction of this roll by a servo motor and a ball screw, and the laser sensor which measures the distance between rolls between the said fixed roll and a moving roll is provided, A load sensor for measuring the press pressure between the rolls is provided, and an electronic automatic control mechanism for feeding back a detection signal caused by each sensor over time to manage the fixed roll and the moving roll at a constant distance and a constant press pressure is provided. A roll mill characterized in that the servo motor is driven by an electronic automatic control mechanism to adjust the position of the moving rolls sequentially. It is provided.

The roll mill is a three roll mill having three rolls parallel to each other in the horizontal direction, wherein the middle roll fixed in the center of the temporary object is used as a fixed roll, and the roll rolls provided before and after the rolls, respectively. A roll mill is provided which makes a moving roll which can be controlled automatically.

The automatic control is also based on displacement control which controls the distance between rolls by the laser sensor while monitoring the load by the load sensor. Then, when a large disturbance occurs, the program is temporarily switched from the displacement control to the load control, and the program is returned to the displacement control from the load control immediately after the disturbance convergence. Further, the distance between rolls is programmed as a value obtained by adding a function of time [e (t)] representing a temporal change of the film thickness of the processing material through the nip to the distance between roll axes D taking into account the crushing of the roll in operation. The above automatic control is provided.

Since the present invention is configured as described above and controlled by feedback control so as to maintain a predetermined roll-to-roll distance over time by using displacement control and load control together, a constant press pressure (reaction force) distribution on a contact line using a crown-attached roll And constant rolls always scheduled in response to self-alignment or crushing margins of rolls, changes in viscosity of processed materials, occurrence of abnormal loads, etc., without losing the dispersion effect from the frictional force generated from the roll rotation of the rolls. Roll mills, such as three roll mills which can operate under a contact force, are obtained, and by using this roll mill as a disperser, it becomes possible to respond to high dispersion quality (precision) requirements. In other words, the particle size distribution after dispersion is also narrower than that of the conventional roll mill, and by automatic control, it becomes possible to transfer the operation reliant on human control technology from a person to a machine.

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to various roll mills used for kneading and dispersing materials such as fine powder and nano particles in a processing material in the manufacturing process of various products such as ink, paint, ceramics, chemicals, food, electronic materials and the like. 5 and 6, as an embodiment of the roll mill of the present invention, the center roll 1 is fixed, and the front roll 2 and the back roll 3 before and after the transverse direction. Three roll mills are shown which are installed in parallel, in contact and separation. In Fig. 5, the bearing 5 supporting the roll shaft 4 of the middle roll 1 is fixed to a mount (frame) (not shown) so that the front roll 2 and the rear roll 3 are formed on both sides thereof. It is located.

The front roll 2 and the rear roll 3 are installed with almost the same mounting structure on the mount, and FIG. 6 shows an embodiment of the mounting portion. In the drawing, the servo motor bracket 6 fixed to the mount is shown on the left side. And a displacement-driven servo motor (not shown) is installed thereon, and the rotational force of the servo motor is transmitted to the ball screw coupling 7. At the same time as the rotational force is transmitted, the reaction force transmitted through the ball screw 8 is also received and transmitted to the motor bracket 6. Thereby, the bearing 9 is included in both, and the load cell (load sensor) 10 for reaction force measurement at once is mounted between the bracket 6 and the bearing 9.

The ball screw 8 and the ball screw coupling 7 are securely engaged by key engagement, and the rotational force is transmitted to the ball screw. The rotational force in the ball screw is converted into a forward force (propulsion force) to transmit the forward force (propulsion force) to the roll bearing holder 12 through the roll push bar 11.

The ball screw 8 and the roll push bar 11 are attached to the same screw fixing plate 13, and the screw fixing plate is equipped with the LM (linear motion) guide 14. As shown in FIG. Moreover, the same LM guide 15 is attached to the roll bearing holder 12, and these two LM guides are manufactured so that they may move on two common rails, and both straightness is maintained.

In the embodiment shown in FIG. 6, the ball screw 8 is movably supported in the axial direction, and the ball screw 8 is fixed to the screw fixing plate 13, and the screw fixing plate 13 is LM. (Linear motion) The frame is attached so that a movement is possible through the guide 14. 7 shows an embodiment in which the retaining plate is fixed to the frame, the retaining plate 13a is fixed to the frame, and the ball screw 8 is inserted into the retaining plate 13a through a bearing 20 such as a cylindrical radial bearing. It is. By this configuration, the ball screw is movable in the axial direction while being supported by the holding plate.

The roll shaft 16 of the post-roll (pre-roll) main body is attached to the bearing in the roll bearing holder 12. Drive rolls (not shown) are respectively connected to the roll shaft 16 via the Schmitt coupling 17. Since the Schmidt coupling 17 is a mechanism that enables parallel movement of the shaft during rotation in the transmission of power with different shaft centers, the rotational driving force from the drive motor while allowing the movement in the perpendicular direction to the roll shaft 16 by this mechanism. Can be transmitted to this roll shaft 16 at constant speed.

In order to accurately measure the distance between the servo motor bracket 6 and the roll, a laser displacement meter (laser sensor) 18 is fixed to the servo motor bracket 6, and the laser beam is directly irradiated to the roll flange portion at the end of the roll. We are measuring distance.

The servo motor bracket 6 is fixed to the mount, and the bearing 5 of the roll shaft 4 of the roll 1 is also fixed to the mount so that the distance between the servo motor bracket 6 and the roll (flange) is fixed to the mount. By measuring the distance between the roll shaft 4 of the middle roll and the roll shaft 16 of the after roll 3 (pre-roll 2) can be measured. The distance between the servo motor bracket 6 and the roll (flange) is determined by the initial press pressure (static) in the roll stop state, and then the feedback control is performed to make this constant during roll driving. Due to this control, ball screw propulsion by servomotor rotational force is used. In addition, an electronic automatic control mechanism is provided to drive the servo motor instantaneously by feedback control and to manage it at a constant distance and a constant press pressure.

As shown in FIG. 5, the control system shown in FIG. 6, FIG. 7 is equipped in four places by the left and right both ends of the front roll 2, and the left and right both ends of the back roll 3, and they are the same plane. It is fixed to the target of an image through an LM guide, and both left and right ends of a middle roll are fixed to the target of an image. Therefore, when the roll mill is operated, the distance between the rolls and the roll-to-roll pressure acting on the rolls are caused by the laser sensor 18 and the load sensor (load cell) 10 at the instant of the moment, so that the detection signal from the sensor is detected. By feeding back the servo motor and moving the roll shaft 16 in the direction perpendicular to the roll, the servo motor can be optimally operated at a constant distance and at a constant press pressure, thereby improving the dispersion effect. At this time, automatic control is based on the displacement control which controls the distance between rolls by a laser sensor, monitoring a load by a load sensor as mentioned above. Then, when a large disturbance occurs, the program is temporarily switched to control from displacement control to load control, and the program is returned to load control from displacement control immediately after disturbance convergence. In addition, the above-mentioned in which the roll-to-roll distance is programmed as a value obtained by adding a function of time [e (t)] representing a temporal change in the film thickness of the processing material through the nip to the roll-to-axis distance D considering the crushing of the roll during operation. Automatic control is also adopted.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows the crown curve, a roll contact line, etc., when the fixed roll and the press side roll (moving roll) are contacting under constant press pressure.

It is explanatory drawing which shows the distribution press pressure (reaction force) on the contact line in roll contact state.

It is explanatory drawing explaining the relationship of the press pressure distribution on a contact line, and a self alignment force.

It is explanatory drawing which shows the distance between rolls with the crushing margin of the roll when a press pressure is applied.

5 is a plan view of a roll mill showing an embodiment of the present invention.

It is a front view which showed the installation part of the street of a moving roll.

It is a front view which shows another Example of the installation part by the side of the moving roll.

Claims (7)

A roll mill used for kneading and dispersing a substance such as fine powder and nano particles in a treatment material, comprising: a fixed roll fixed to a target object and a moving roll provided to be contacted / separated from the fixed roll, A rod for moving the roll by a servo motor and a ball screw so that it can be moved in the perpendicular direction of the roll, and a laser sensor for measuring the distance between the rolls between the fixed roll and the moving roll, and measuring the press pressure between the rolls. An electronic automatic control mechanism is provided for providing a sensor and feeding back a detection signal generated over time from each sensor to manage a fixed distance between the fixed roll and the moving roll at a constant distance and a constant press pressure. The roll mill which drives a servo motor so that the position of a moving roll can be adjusted one by one. The method of claim 1, The roll mill is a three roll mill having three rolls parallel to each other: a middle roll fixed in the center of the mount as a fixed roll, and a roll before and after the double roll installed as a moving roll. The contact roll between the rolls generated between the front roll, the middle roll and the after roll is a moving roll movable by the servo motor and the ball screw in the direction perpendicular to the middle roll so that any position on the contact line becomes equivalent. Characterized by roll mill. The method of claim 2, Crowns are formed on the front roll, the middle roll, and the after roll, and the change of the press pressure according to the difference in frictional force caused by the differential rotation between the pair rolls of the front roll, the middle roll, the middle roll, and the after roll is summed up, The roll mill which feeds back to an electronic automatic control mechanism. The method of claim 3, wherein And the electronic automatic control mechanism is a displacement control for controlling the distance between the rolls by the laser sensor while monitoring the load by the load sensor. The method of claim 4, wherein The electronic automatic control mechanism is a displacement control that controls the distance between the rolls by the laser sensor while monitoring the load by the load sensor, and temporarily stops from the displacement control to the load control by the load sensor when a large disturbance occurs, although not enough to make an emergency stop. A roll mill, wherein the program is a program for switching from load control to displacement control immediately after disturbance convergence. The method of claim 4, wherein The inter-roll distance is a function of the interaxial distance (D) taking into account the crushing of the roll contact surface during operation, the film thickness (e) of the processing material through the nip between the rolls, and the time according to the time change of the film thickness (e) [ e (t)] roll mill. The method of claim 2, Each roll shaft of the front roll and the rear roll of the moving roll is connected to a drive motor, respectively, and a schmitt coupling is provided between the drive motor and the roll shaft of each roll to allow movement in a direction perpendicular to the roll axis. Roll mill.

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