JP2004050252A - Pressing apparatus for side weir of twin roll and pressing control method for side weir - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simplified pressing apparatus for the side weirs of twin rolls provided on both edge faces in the width direction of parallel casting rolls, and to provide a pressing control method for the side weirs. <P>SOLUTION: The apparatus is provided with a spindle cylinder 1 pressing side weirs via a thruster 5 whose nose is rotatably connected to each side weir and a spindle cylinder rod 3 connected to the heel of the thruster, a spindle elongation and contraction detector 9 provided on the spindle cylinder, a spindle load detector 4 detecting the pressure of the spindle, a tilt cylinder 11 arranged in the vertical upper direction of the spindle cylinder, and in which the nose of the tilt cylinder rod 12 is rotatably connected to each side weir, a tilt elongation and contraction detector 19 provided on the tilt cylinder, a tilt load detector 15 detecting pressure, and a connection member 16 for a tilt freely rotatably connecting the heel of the tilt cylinder to the spindle cylinder rod 3. A pressing pivot point P on the side of the side weir of the thruster 5 is arranged on the common tangent of a pair of casting rolls, and also, in the vicinity of the area centroid in the axially vertical cross section of a molten metal pool. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a twin-roll side weir pressing device and a side-weir pressing control method that can simplify a side weir pressing device provided on both widthwise end faces of a parallel casting roll.
[0002]
[Prior art]
7 is a perspective view schematically showing a main part of a twin roll side weir pressing device as an example of a conventional apparatus, and FIG. 8 is a side view in which a main part of FIG.
[0003]
7 and 8, reference numeral 51 denotes a pair of casting rolls constituting a twin roll. The casting rolls 51 are disposed horizontally and parallel so as to form a roll gap therebetween, and are provided inside. It is cooled by the cooling structure, and is supported by the rotating shaft 55 so as to rotate in opposite directions as indicated by arrows a and a 'in FIG. 52 is a pair of side weirs, the refractory 52a of which is provided so as to slide in close contact with both end seal portions 51a formed in a step-like shape of the casting roll 51, and a roll gap of the casting roll 51. A pool of molten metal R (molten metal pool) is formed at the upper part of the space. Reference numeral 53 denotes three pressing cylinders parallel to the axis of the casting roll 51, and the front ends are respectively mounted at three places on the back surface of both side weirs 52.
[0004]
At the time of continuous casting of the metal strip S, first, both the casting rolls 51 are rotated, and the refractories 52a of both the side dams 52 are pressed against the both end seal portions 51a with a predetermined force by the pressing cylinder 53 to form the molten metal R. Prevent leaks. Next, the molten metal R is continuously supplied to a pool formed by both the casting rolls 51 and the side dams 52, solidified into a plate shape by the casting rolls 51, and the metal strip S is drawn out from below.
[0005]
[Problems to be solved by the invention]
However, in the conventional apparatus, the pressure of each pressing cylinder 53 is maintained even when the contact surface of the refractory 52a is worn. However, the material, temperature, contact conditions, and the like at the location where the refractory 52a is pressed against the seals 51a at both ends are not always the same, and a partial difference occurs in the amount of wear of the refractory 52a due to sliding with the seals 51a at both ends. However, there is no place where the wear easily progresses in the easily wearable portion, and the uneven wear shortens the life of the refractory 52a. Therefore, it is necessary to frequently replace the side weir 52, which is a factor that hinders an increase in the continuous casting time and the continuous casting amount.
[0006]
Therefore, Japanese Patent Publication No. 8-32358 was proposed to solve such a problem. In Japanese Patent Publication No. 8-32358, the pressing amounts of the pressing cylinders 53 provided at the three locations are monitored, and the pressing amounts of all the pressing cylinders 53 are equalized, so that the refractory 52a surface of the side weir 52 is In order to maintain the parallel relationship with the sealing portions 51a at both ends of the casting roll 51, a difference from the largest pressing amount (= abrasion amount) is obtained, and the origin of the stroke of each pressing cylinder 53 is set at both ends according to the difference. Pressing amount control for moving to the portion 51a side is performed.
[0007]
However, as described above, the side weir 52 is supported by the three pressing cylinders 53, and each pressing is performed so as to maintain the parallel relationship between the both end seal portions 51a and the side weir 52 so that the side weir 52 has a uniform wear amount. In the method of controlling the pressing amount of the cylinder 53, each pressing cylinder 53 receives the weight of the side weir 52 itself, and further receives the downward moving force by the frictional force pressing the side weir 52 against the seal portions 51a at both ends. Therefore, the pressing cylinder 53 needs to have strength enough to withstand this load. Therefore, arranging the large-diameter three-point pressing cylinder 53 requiring such strength in a narrow space between the twin-roll rotating shafts 55 has a structural problem.
[0008]
Further, in the above-mentioned proposed patent, the attitude control of the side weir 52 is limited to the three pressing cylinders 53, and the difference between the original stroke amount and the current stroke amount is obtained. The deviation value between them is obtained, and the position of the side weir 52 is controlled by pushing out the pressing cylinder 53 on the side with a small amount of wear according to the maximum deviation value. When it is attempted to correct the pressure to zero, the control for predicting and maintaining the posture of the side weir contact surface in contact with the casting roll seal portion 51a becomes complicated, and furthermore, there is a problem that individual pressing forces fluctuate and an excessive pressing force is generated. there were.
[0009]
SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a twin roll side weir pressing device and a side weir pressing control method capable of pressing a side weir provided by a twin roll by a simple configuration and control. The purpose is to do.
[0010]
[Means for Solving the Problems]
The invention according to claim 1 supplies a molten metal to a pair of casting rolls arranged substantially horizontally and a pair of side dams in contact with both ends in the width direction of the casting rolls to form a molten metal pool. A twin roll side weir pressing device for solidifying in a shape, a main shaft pressing a side weir via a thruster rotatably connected at a front end to each side weir and a main shaft cylinder rod connected to a rear end of the thruster. A cylinder, a spindle expansion / contraction detector provided for the spindle cylinder, a spindle load detector for detecting the spindle pressing force provided for the spindle cylinder rod, and a front end of the tilt cylinder rod arranged vertically above the spindle cylinder. A tilt cylinder rotatably connected to the side weir, a tilt expansion / contraction detector provided in the tilt cylinder, a tilt load detector for detecting a pressing force of the tilt cylinder, A tilt connecting member that rotatably connects a rear end of a cylinder to the main shaft cylinder rod, and a pressing pivot point on a side weir side of the thruster is provided on a common tangent line of the pair of casting rolls and the molten metal pool. The present invention relates to a twin-roll side weir pressing device arranged near the center of gravity of an area perpendicular to the axis.
[0011]
The twin roll according to claim 1, wherein two tilt cylinders are provided, and the tilt cylinder is arranged symmetrically to a common tangent of the pair of casting rolls and above the spindle pressing position. Side weir pressing device.
[0012]
The invention according to claim 3 relates to the twin-roll side weir pressing device according to claim 1 or 2, wherein a cooler is provided on the thruster and the tilt cylinder rod.
[0013]
The invention according to claim 4 is the pressing control method of the twin roll side weir according to claim 1, 2 or 3, wherein the main shaft cylinder is operated before casting is started, and the side weir is controlled by a predetermined main shaft pressing load. The pressing force is set by the spindle load detector and the tilt load detector by pressing against the casting roll, and the amount of expansion and contraction is detected as needed by the main shaft expansion and contraction amount detector and tilt expansion and contraction detector. Then, after the start of casting, the pressing load and the amount of expansion and contraction are continuously calculated by comparing the change with each of the initial values, and the uneven wear amount is calculated by the expansion and contraction amount of the spindle cylinder and the tilt cylinder. If the uneven wear amount exceeds the specified value, the pressing force on the side where the uneven wear amount is large is reduced, and if the uneven wear amount is restored within the specified value, each pressing force is restored to the initial state. Twin ro Pressing control method of Le of side weirs which relate to.
[0014]
According to the above means, the following operation is performed.
[0015]
According to the first aspect of the present invention, the configuration includes a main cylinder for controlling the pressing force of the side weir and holding the side weir, and a tilt cylinder for controlling the pressing force of the side weir in the longitudinal direction. The side weir pressing device having such a configuration can prevent uneven wear of the side weir, so that the side weir pressing device can be easily arranged in a narrow space between the rotating shafts of the twin rolls.
[0016]
Further, the main cylinder may be controlled so as to always press the side weir against the seals at both ends of the casting roll with a minimum necessary constant pressure, and the tilt cylinder presses the upper part of the side weir with a predetermined constant pressure. Since the control may be performed in such a manner, the control is remarkably simplified, so that the side weir pressing device can be provided at low cost.
[0017]
According to the second aspect of the invention, the side portion of the side weir is pressed against the end surface of the casting roll with a predetermined constant pressure by the two tilt cylinders. Will be able to actively prevent.
[0018]
According to the third aspect of the present invention, since the thruster and the tilt cylinder rod are provided with the cooler, it is possible to prevent the main spindle cylinder, the tilt cylinder and the respective detectors from being affected by heat.
[0019]
In the invention according to claim 4, the side weir is pressed against the casting roll by the main shaft cylinder so as to have a predetermined main shaft pressing load, and further, the expansion and contraction amount is detected by the main shaft expansion and contraction amount detector and the tilt expansion and contraction amount detector, Each detection value is stored as an initial value, and after the start of casting, the pressing load and the amount of expansion and contraction are continuously calculated by comparing the change with each of the initial values. The uneven wear amount is detected, and if the uneven wear amount exceeds the predetermined value, the pressing force on the side with the larger uneven wear amount is reduced.If the uneven wear amount is restored to within the predetermined value, each pressing force is initialized. Thus, the side weir is pressed against the end face of the casting roll with a constant pressing force by a simple control to prevent uneven wear.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be specifically described with reference to FIGS. In addition, the same members and parts as those of the conventional device are denoted by the same reference numerals in FIGS. 1 to 3, and overlapping description will be omitted.
[0021]
1 is a side view of a pressing device for a twin roll side weir, FIG. 2 is a plan view of FIG. 1, and FIG. 3 is a view taken in the direction of arrows III-III in FIG. 1 to 3, reference numeral 1 denotes a main spindle cylinder for pressing the side weir 52 against both end seal portions 51 a of the casting roll 51. The main spindle cylinder 1 is located outside the casting roll 51 in the width direction (when the roll gap is extended). ) Is horizontally fixed on a fixed base 2 provided in the above. Reference numeral 3 denotes a spindle cylinder rod which expands and contracts with respect to the spindle cylinder 1 by a servo valve (not shown). A thruster 5 is connected to a tip of the spindle cylinder rod 3 via a spindle load detector 4 such as a load cell.
[0022]
The front end of the thruster 5 is provided with a spherical bush 8 on a spindle side weir side pin 7 provided on a bracket 6 formed on the rear surface of the side weir 52, and is rotatably connected to the spherical bush 8. At this time, as shown in FIG. 3, the pressing pivot point P at which the thruster 5 is attached to the side weir 52 by the spherical bush 8 is located on the pair of casting rolls 51, 51 and the common tangent line A and the pool of the molten metal R. It is located near the center of gravity of the cross section perpendicular to the axis of the (molten pool).
[0023]
The main shaft cylinder 1 has sufficient strength to hold the weight of the side weir 52 and to hold the downward moving force received by the side weir 52 due to the frictional force pressing the side weir 52 against the seals 51a at both ends. Further, the spindle cylinder 1 is controlled so as to press the refractory 52a of the side dam 52 against the seals 51a at both ends with a predetermined constant pressure.
[0024]
The spindle cylinder 1 is provided with a spindle expansion / contraction amount detector 9. A cooler 10 is provided inside or outside the thruster 5 by a cooling water flow path or the like to protect the spindle cylinder 1 and the spindle load detector 4 from heat.
[0025]
A tilt cylinder 11 parallel to the axis of the spindle cylinder rod 3 is disposed vertically above the spindle cylinder rod 3. In FIGS. 1 and 2, the front end of the tilt cylinder rod 12 of the tilt cylinder 11 is provided with a spherical bush 14 on a tilt side dam side pin 13 provided on a bracket 6 formed on the rear surface of the side dam 52. To be rotatable. The rear end of the tilt cylinder 11 is connected to a tilt connecting member 16 via a tilt load detector 15 such as a load cell. The rear end of the tilt connection member 16 is attached to a bracket 17 fixed to the spindle cylinder rod 3 via pins 18 so as to be rotatable up and down.
[0026]
The tilt cylinder 11 is provided with a tilt expansion / contraction detector 19. A cooler 20 is provided inside or outside the tilt cylinder rod 12 with a cooling water flow path or the like to protect the tilt cylinder 11 and the tilt load detector 15 from heat. The tilt cylinder 11 is controlled so as to press the upper portion of the side weir 52 against both end seal portions 51a. The pressing force of the tilt cylinder 11 at this time is smaller than the pressing force of the main shaft cylinder 1 pressing the side weir 52, and the pressing amount of the tilt cylinder 11 equalizes the amount of vertical wear of the refractory 52a. Is set to
[0027]
Although the tilt cylinder 11 is shown above the main shaft cylinder rod 3 in the illustrated example, the tilt cylinder 11 may be provided below the main shaft cylinder rod 3. Numeral 11 indicates a case where it is provided in parallel with the axis of the main shaft cylinder rod 3, but it may be provided so as to be vertically inclined with respect to the axis of the main shaft cylinder rod 3.
[0028]
The operation of the above embodiment will be described below.
[0029]
In the configuration shown in FIGS. 1 to 3, the casting roll 51 is rotated reciprocally, and the molten metal R is supplied to the oil sump formed on the roll gap by the refractory 52 a of the side weir 52 pressed against the seals 51 a at both ends of the casting roll 51. When the supply and the casting of the metal strip S are started, the main cylinder 1 presses the refractory 52a of the side weir 52 against the seals 51a at both ends at a predetermined constant pressure. Due to the vibration and sliding of the side weir 52, the refractory 52a sliding on the seal portions 51a at both ends is worn, and the main body cylinder rod 3 of the main shaft cylinder 1 follows the wear by the amount of wear, and the refractory 52a is pressed at a constant pressure. Press.
[0030]
At this time, the tilt cylinder 11 provided on the upper part of the telescopic rod 3 sets the upper part of the side weir 52 to a predetermined pressing force smaller than the pressing force of the main shaft cylinder 1 and presses so as to maintain the initial posture. The pressing force on the casting roll 51 is controlled by the sum of the main shaft pressing force and the tilt pressing force. Thereby, the refractory 52a is uniformly pressed against the contact surface without generating excessive pressing force, and uneven wear can be suppressed.
[0031]
When the side weir 52 is pressed against the seals 51a at both ends of the casting roll 51, the thruster 5 and the front end of the tilt cylinder rod 12 are attached to the side weir 52 by the spherical bushes 8, 14, so Reference numeral 52 indicates that the upper and lower sides and the left and right sides are pressed with a constant pressing force following the sealing portions 51a at both ends of the casting roll 51.
[0032]
According to the above, uneven wear of the refractory 52a of the side weir 52 can be prevented, and the life of the side weir 52 can be extended.
[0033]
Further, a configuration is provided that includes a high-strength (thick) main spindle cylinder 1 for controlling the pressing force of the side weir 52 and holding the side weir 52, and a tilt cylinder 11 for controlling the pressing force of the side weir 52 in the front-rear direction. Therefore, it is possible to easily arrange the side weir pressing device in a narrow space between the rotation axes of the twin rolls as a simple configuration.
[0034]
Further, the spindle cylinder 1 may be controlled so as to always press the refractory 52a of the side weir 52 against both end seals 51a at a predetermined constant pressure, and the tilt cylinder 11 holds the upper part of the side weir 52 by the spindle cylinder. Control may be performed so as to press at a predetermined constant pressure smaller than one pressing force, so that control can be significantly simplified.
[0035]
Next, another embodiment of the present invention will be described.
[0036]
In the configurations of FIGS. 4 and 5, a single tilt cylinder 11 is disposed immediately above the main spindle cylinder rod 3 in the configurations of FIGS. 1 to 3, whereas a pair of The two tilt cylinders 11a and 11b are arranged so as to be symmetrical with respect to the common tangent line A of the casting rolls 51 and 51. Each of the tilt cylinders 11a and 11b is attached to a bracket 17 fixed to the main shaft cylinder rod 3. On the other hand, it is attached rotatably by a pin 18. It is configured to be assembled to the main shaft cylinder rod 3. The tilt cylinders 11a and 11b have the same configuration as the tilt cylinder 11, and include tilt load detectors 15a and 15b and tilt expansion / contraction detectors 19a and 19b.
[0037]
Next, a pressing control method according to the embodiment shown in FIGS. 4 and 5 will be described with reference to FIG.
[0038]
In the side weir pressing device of FIG. 6, the spindle cylinder 1 is operated before the start of casting, and the side weir 52 is pressed against the casting roll so as to have a predetermined main shaft pressing load, and the main shaft load detector 4 and the tilt load detector 15a. , 15b are set.
[0039]
Further, the main shaft expansion / contraction amount detector 9 and the tilt expansion / contraction amount detectors 19a and 19b detect the amount of expansion / contraction at any time, and store the detected values as initial values.
[0040]
The total pressing force of the spindle load detector 4 and the tilt load detectors 15a and 15b is obtained by adding in the adder 21, and the added value is input to the comparator 22 and compared with the set pressing force provided. , Each pressing force is corrected by one percentage.
[0041]
Further, the difference Δ1 is obtained by subtracting the detection value SG1 of the main shaft expansion / contraction amount detector 9 and SG2 of the tilt expansion / contraction amount detector 19a by the subtractor 23, and calculating the deviation Δ1 from the detection value SG1 of the main shaft expansion / contraction amount detector 9 and the tilt expansion / contraction. The deviation Δ2 is obtained by subtracting SG3 of the amount detector 19b, and the deviation Δ1 and the deviation Δ2 are compared by the comparator 25. If the comparison result is +, the pressing force of the tilt cylinder 11a is reduced by a certain amount. If the comparison result is negative, control is performed to reduce the pressing force of the tilt cylinder 11b.
[0042]
When the deviations Δ1 and Δ2> 0, control is performed to reduce the pressing force of the tilt cylinders 11a and 11b, and when the deviations Δ1 and Δ2 <0, control is performed to reduce the pressing force of the spindle cylinder 1. .
[0043]
As described above, the uneven wear amount is detected from the calculated value of the expansion and contraction amount of the main spindle cylinder and the tilt cylinder, and when the uneven wear amount exceeds a predetermined value, the pressing force on the side where the uneven wear amount is large is reduced, and the uneven wear amount is reduced. When the wear amount is restored within a predetermined value, each pressing force is controlled to be restored to the initial state.
[0044]
Accordingly, by attaching the tilt cylinders 11a and 11b to the main shaft cylinder rod 3 as described above, the posture of the side weir 52 can be directly detected, and correction without disturbance due to thermal expansion or the like can be easily performed. Can control.
[0045]
Further, when uneven wear (deviation of the amount of tilt expansion / contraction) occurs, instead of directly correcting the position of the side weir, a change in wear of the spindle cylinder 1 with respect to the pressing pivot point P is detected, and the pressing of each point is detected. The pressure distribution is controlled, the pressing force at the maximum wear point (compared to the three points of the main cylinder 1 and the tilt cylinders 11a and 11b) is reduced, and the pressing force at the other wear points is calculated by a predetermined total pressing force. By doing so, it is possible to promote the wear of a portion having a small uneven wear amount, thereby effectively eliminating uneven wear.
[0046]
It should be noted that the present invention is not limited only to the above-described embodiment, and it goes without saying that various changes can be made without departing from the spirit of the present invention.
[0047]
【The invention's effect】
According to the first aspect of the present invention, since the main cylinder for controlling the pressing force of the side dam and holding the side dam and the tilt cylinder for controlling the pressing force of the side dam in the front-rear direction are provided. The side weir pressing device having a simple configuration can prevent uneven wear of the side weir, so that the side weir pressing device can be easily arranged in a narrow space between the rotating shafts of the twin rolls.
[0048]
Further, the main cylinder may be controlled so as to always press the side weir against the seals at both ends of the casting roll with a minimum necessary constant pressure, and the tilt cylinder presses the upper part of the side weir with a predetermined constant pressure. Since the control may be performed in such a manner, the control is significantly simplified, so that there is an effect that the side weir pressing device can be provided at low cost.
[0049]
According to the second aspect of the present invention, the side portion of the side weir is pressed against the end face of the casting roll with a predetermined constant pressure by the two tilt cylinders. Also has the effect of being able to actively prevent.
[0050]
According to the third aspect of the present invention, since the thruster and the tilt cylinder rod are provided with the cooler, there is an effect that the main shaft cylinder, the tilt cylinder, and each detector can be prevented from being affected by heat.
[0051]
According to the invention described in claim 4, the side weir is pressed against the casting roll by the main spindle cylinder so as to have a predetermined main spindle pressing load, and further, the expansion / contraction amount is detected by the main shaft expansion / contraction amount detector and the tilt expansion / contraction amount detector. , Each detected value is stored as an initial value, and since the start of casting, the pressing load and the amount of expansion and contraction are continuously calculated by comparing changes with the respective initial values, and the calculated value of expansion and contraction between the spindle cylinder and the tilt cylinder is calculated. When the uneven wear amount exceeds a predetermined value, the pressing force on the side where the uneven wear amount is large is reduced, and when the uneven wear amount is restored to within the predetermined value, each pressing force is Since the initial state is restored, the side dam is pressed against the end face of the casting roll with a constant pressing force by a simple control, so that there is an effect that uneven wear can be prevented.
[Brief description of the drawings]
FIG. 1 is a side view showing an embodiment of a pressing device for a side weir of a twin roll according to the present invention.
FIG. 2 is a plan view of FIG.
FIG. 3 is a view taken in the direction of arrows III-III in FIG. 1;
FIG. 4 is a plan view showing another example of the pressing device for the side weir of the twin roll according to the present invention.
FIG. 5 is a view in the direction of arrows VV in FIG. 4;
FIG. 6 is a block diagram showing a pressing control method of the apparatus of FIG.
FIG. 7 is a perspective view schematically showing a main part of a pressing device of a twin roll side weir as an example of a conventional device.
FIG. 8 is an enlarged side view of a main part of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Main shaft cylinder 3 Main shaft cylinder rod 4 Main shaft load detector 5 Thruster 8 Spherical bush 7 Horizontal pin 9 Main shaft expansion / contraction detector 10 Cooler 11 Tilt cylinder 11a Tilt cylinder 11b Tilt cylinder 12 Tilt cylinder rod 14 Spherical bush 15 Tilt load detector 16 Tilt connecting member 19 Tilt expansion / contraction detector 20 Cooler 51 Casting roll 52 Side weir P Press pivot point

Claims (4)

A pair of casting rolls arranged substantially horizontally and a pair of side rolls for supplying molten metal to a molten metal pool formed by abutting a pair of side dams at both ends in the width direction of the casting rolls and solidifying into a strip shape. A weir pressing device, comprising: a thruster having a front end rotatably connected to each side weir; a main spindle cylinder for pressing a side weir via a main cylinder cylinder rod connected to a rear end of the thruster; and a main cylinder. A main shaft expansion / contraction detector, a main shaft load detector for detecting the main shaft pressing force provided in the main shaft cylinder rod, and a front end of the tilt cylinder rod disposed vertically above the main shaft cylinder and rotatable with respect to the side weir. A tilt cylinder connected to the tilt cylinder, a tilt expansion / contraction detector provided in the tilt cylinder, a tilt load detector for detecting a pressing force of the tilt cylinder, and a rear end of the tilt cylinder. A tilt connecting member rotatably connected to the shaft cylinder rod, and a pressing pivot point on the side weir side of the thruster is set on a common tangent to the pair of casting rolls and an area center of gravity of a cross section perpendicular to the axis of the melt pool. A twin roll side weir pressing device, which is disposed in the vicinity. 2. The twin-roll side weir pressing device according to claim 1, wherein two tilt cylinders are provided, and are arranged symmetrically with respect to a common tangent to the pair of casting rolls and above the main shaft pressing position. 3. 3. The device according to claim 1, wherein the thruster and the tilt cylinder rod are provided with a cooler. 4. A method for controlling the pressure of a side weir of a twin roll according to claim 1, 2 or 3, wherein a spindle cylinder is actuated before starting casting, and the side weir is pressed against the casting roll by a predetermined spindle pressing load. The pressing force is set by the detector and the tilt load detector, and the expansion and contraction amount is detected by the main shaft expansion and contraction amount detector and the tilt expansion and contraction detector as needed, and each detected value is stored as an initial value. Since the start of casting, the pressing load and the amount of expansion and contraction are continuously calculated by comparing the changes with the respective initial values, and the uneven amount of wear is detected based on the calculated value of the expansion and contraction between the spindle cylinder and the tilt cylinder. When the value exceeds the value, the pressing force on the side where the uneven wear amount is large is reduced, and when the uneven wear amount is restored within a predetermined value, each pressing force is restored to the initial state. Of side weir Method.

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