JP4804944B2 - Sheet forming device - Google Patents

Description

The present invention relates to a sheet forming apparatus, and more particularly to a touch roll type sheet forming apparatus that forms a sheet in a state where a sheet is passed between two rolls and the front and back surfaces of the sheet are in contact with the two rolls.

  As a sheet forming apparatus by an extrusion method, it has two rolls arranged in parallel with a gap, and a sheet (extruder, molten resin from a T die) is passed between two rolls that are driven to rotate, There is a touch roll type that forms a sheet in a state where the front and back surfaces of the sheet are in contact with the two rolls (for example, Patent Documents 1 and 2).

  In sheet forming with a touch roll type sheet forming device, the accuracy of the gap between the two rolls that contact the front and back surfaces of the sheet to be formed (hereinafter referred to as the roll gap) greatly affects the product quality of the sheet. In order to form a product quality sheet, it is required to eliminate fluctuations in the roll gap under sheet forming and keep the roll gap constant.

In the conventional sheet forming apparatus, a wedge member is inserted between roll support housings (bearing housings) of two rolls, and one roll support housing is pressed against the other roll support housing by a hydraulic cylinder device to support the two rolls. The roll gap is adjusted by the amount of the wedge member inserted between the housings.
JP-A-9-155948 Japanese Patent Laid-Open No. 10-34748

  With the wedge-type roll gap setting, the roll gap can be made constant, but the roll gap cannot be changed and set automatically by changing the control target value of the roll gap according to various conditions of sheet forming. .

  In contrast, it is conceivable to perform roll position control by a feedback control type servo control system. This type of position control includes a semi-closed system that feeds back the position of the drive system that sets the roll position, a fully closed system that feeds back the roll position itself, and a hybrid system that combines the semi-closed system and the fully closed system. Is well known.

  Full-closed type and hybrid type feedback control detects the roll position itself, so it can perform position control with higher accuracy than the semi-closed type, but absolute displacement such as a linear scale that detects the roll position. In order to increase the resolution of the meter, there is a problem that there is a physical limit as compared with the incremental displacement meter.

  In the feedback control using the position signal of the displacement meter, in the steady state where the positioning is completed, regardless of the presence or absence of external force, the width of the range corresponding to the minimum unit plus 1 unit and minus 1 unit of the displacement meter position signal Since the control object of position control, that is, the roll fluctuates (goes back and forth) in the roll gap increase / decrease direction, fluctuation vibration occurs. Therefore, the larger the displacement meter resolution, the larger the fluctuation vibration amplitude.

Therefore, the feedback control of the full-closed type and hybrid type, when applied to a sheet forming device of the touch roll, the roll gap in the steady state in which the positioning is completed, vary depending on the resolution of the A blanking Soryuto displacement meter It will be, will not be able to keep the roll gap required for the order to obtain the required product quality.

  Particularly, in the hydraulic servo type using a hydraulic cylinder device as means for moving the roll in the roll gap increasing / decreasing direction, the position of the hydraulic cylinder device is always pushed and pulled to maintain the position, so the roll gap is slight. In a sheet that fluctuates and requires high accuracy, the slight fluctuation affects the product quality, and the required product quality cannot be obtained.

  The problem to be solved by the present invention is that, in a touch roll type sheet forming apparatus, fluctuations in the roll gap due to inevitable fluctuation vibration in feedback control are minimized, and this is compatible with high-accuracy position control. It is to enable stable production of high product quality sheets under precise roll gap setting.

The sheet forming apparatus according to the present invention has two rolls arranged in parallel with a gap, and a sheet is passed between the two rolls that are rotationally driven, and the front and back surfaces of the sheet are in contact with the two rolls. In a sheet forming apparatus that performs sheet forming in a state where the sheet is formed, linear drive means for adjusting the roll gap by moving at least one of the two rolls in the roll gap increase / decrease direction, and the roll gap increase / decrease direction of the roll a first position detecting means for detecting the position, said has a higher resolution than the resolution of the first position detection means, and a second position detecting means for detecting a position of said linear drive means, the control of the roll gap the target value change to the role position control based on the position information detected by said first position detecting means, before the time of sheet forming by a predetermined control target value And a control means for performing roll position control based on position information detected by the second position detecting means.

The sheet forming apparatus according to the present invention has two rolls arranged in parallel with a gap, and a sheet is passed between the two rolls that are rotationally driven, and the front and back surfaces of the sheet are in contact with the two rolls. In a sheet forming apparatus that performs sheet forming in a state where the sheet is formed, linear drive means for adjusting the roll gap by moving at least one of the two rolls in the roll gap increase / decrease direction, and the roll gap increase / decrease direction of the roll a first position detecting means for detecting the position, said has a higher resolution than the resolution of the first position detection means, and a second position detecting means for detecting a position of said linear drive means, the control of the roll gap At the time of changing the target value, until the deviation between the control target value after the change of the control target value and the roll position measurement value by the first position detecting means becomes a predetermined value or less,置検out performs roll position control based on the position information detected by the means, the deviation between the roll position measurement value is equal to or less than a predetermined value by the control target value after the control target value changing first position detection means A control unit that performs roll position control based on position information detected by the second position detection unit .

In the sheet forming apparatus according to the present invention, preferably, the resolution of the second position detecting means is 0.5 μm or less.

In the sheet forming apparatus according to the present invention, preferably, the first position detecting means is constituted by an absolute displacement meter, and the second position detecting means is constituted by an incremental displacement meter.

In the sheet forming apparatus according to the present invention, preferably, the linear drive means includes a hydraulic cylinder device that moves a roll in a roll gap increasing / decreasing direction, and a servomotor-driven bidirectional hydraulic pressure that controls a hydraulic pressure supply amount to be sent to the hydraulic cylinder device. A hydraulic servo type having a pump, wherein the second position detecting means comprises a displacement meter for measuring the position of the piston of the hydraulic cylinder device, and the control resolution of the bidirectional hydraulic pump per unit The pump volume per rotation of the bidirectional hydraulic pump is set so that the value obtained by converting the pump volume into the piston movement amount of the hydraulic cylinder device is less than the measurement resolution of the displacement meter.

The sheet forming apparatus according to the present invention is preferably set so that a pump volume V (mm ³ ) of the bidirectional hydraulic pump and a cylinder diameter D (mm) of the hydraulic cylinder device satisfy the following relational expression. .

^{V ≦ {(πD 2/4} ) a} / (b / 360)
Where, a: resolution of the displacement type of the linear drive means (mm), b: mechanical control resolution (degrees) of the bidirectional hydraulic pump
In the sheet forming apparatus according to the present invention, the mechanical control resolution b of the bidirectional hydraulic pump is preferably 0.2 degrees.

  In the sheet forming apparatus according to the present invention, preferably, the hydraulic piping between the bidirectional hydraulic pump and the hydraulic cylinder device is configured by flexible piping.

According to the sheet forming apparatus of the present invention, when the control target value of the roll gap is changed, the deviation between the control target value after the change of the control target value and the roll position measurement value by the first position detecting means for detecting the roll position is predetermined. until a value below the roll position control based on the position information detected by the first position detection means is performed, the roll position by the control target value after the control target value changing first position detection means When the deviation from the measured value is less than or equal to a predetermined value, roll position control is performed based on the position of the driving means detected by the second position detecting means having a resolution higher than that of the first position detecting means. so stop the variation of the roll gap due to fluctuation vibration unavoidable in the feedback control to be small due to high resolution of the second position detecting means, which in the first position detection And achieve both high precision position control using the stage, under the correct roll gap settings, it becomes possible to stably produce a high product quality sheets.

  One embodiment of a sheet forming apparatus according to the present invention will be described with reference to FIG.

  The sheet forming apparatus includes a first roll 11, a second roll 12, and a third roll 13 on the fixed base 10. The 1st roll 11, the 2nd roll 12, and the 3rd roll 13 are mutually arrange | positioned in parallel (parallel).

The first roll 11, the left and right shaft end portions 15R, 15L of the left and right bearing housings 16R, is more rotatably supported 16L, and is rotatable about its central axis. The bearing housings 16R and 16L are engaged with the left and right linear guides 17R and 17L provided on the fixed base 10 so as to be displaceable. Thereby, the first roll 11 can be displaced in the direction A in which the roll gap is increased or decreased with respect to the second roll 12. That is, the arrangement position of the first roll 11 can be displaced (changed) in the direction A in which the roll gap with the second roll 12 is increased or decreased.

  Linear scales 42 </ b> R and 42 </ b> L are attached to the fixed base 10. The linear scales 42R and 42L constitute first position detecting means for detecting (measuring) the positions of the left and right bearing housings 16R and 16L, that is, the position of the first roll 11 in the roll gap increasing / decreasing direction (roll gap). . The linear scales 42R and 42L are absolute displacement meters having a resolution of about 1 to 50 μm.

The second roll 12 has left and right shaft end portion 23R, the 23L, fixed-mounted left and right bearing housings 24R to the fixing base 10, a more rotatably supported 24L, it is rotatable on its center axis around ing.

The third roll 13, the left and right shaft end portion 26R, the 26L, fixed-mounted left and right bearing housings 27R to the fixing base 10, a more rotatably supported 27L, is rotatable about its central axis ing. Note that the third roll 13 can be displaced (changed) in the direction A of increasing or decreasing the roll gap with the second roll 12 in the same manner as the first roll 11, and is equivalent to the linear drive means of the first roll 11 described later. The arrangement position in the roll gap increasing / decreasing direction may be adjusted by the linear driving means.

First roll 11, second roll 12, the third roll 13, each individually coupled electric motor 81, 82 and 83 for driving the roll rotation, a first roll 11 the third roll 13 is counterclockwise The second rolls 12 are each driven to rotate in the clockwise direction.

  A T die 100 that is long in the roll axis direction is provided above the roll gap between the first roll 11 and the second roll 12. Molten resin is supplied to the T die 100 from an extruder 110 including a screw 111 that is rotationally driven by a screw drive motor 112. The extruder 110 is a supply source of the molten resin to the T die 100, and the amount of molten resin extruded by the extruder 110 is determined by the rotational speed of the screw 111, that is, the speed control of the screw drive motor 112.

  The T-die 100 discharges the molten resin from the lip toward the roll gap between the first roll 11 and the second roll 12. As a result, a melt bank MB made of a molten resin is formed in the upper part of the gap between the first roll 11 and the second roll 12.

The first roll 11, the third roll 13 is counter-clockwise direction, by the second roll 12 are driven respectively rotated clockwise, the roll gap between the first roll 11 and second roll 12 And in each of the roll gap | interval part of the 2nd roll 12 and the 3rd roll 13, sheet | seat shaping | molding is performed by a touch roll type in the state which the front and back of the sheet | seat S contact the said both rolls.

  Left and right hydraulic cylinder devices 33 </ b> R and 33 </ b> L are mounted on the fixed base 10 by mounting members 31. The piston rods 34R and 34L of the hydraulic cylinder devices 33R and 33L are fixedly connected to the bearing housings 16R and 16L via load cells 43R and 43L, respectively, at the tips.

  The load cells 43R and 43L are pressing load measuring means, and measure the pressing load acting on the first roll 11 at the connecting portion of the piston rods 34R and 34L with the bearing housings 16R and 16L.

  Each of the hydraulic cylinder devices 33R and 33L is a double-acting type having cylinder chambers 72 and 73 on both sides of the piston 71. The hydraulic cylinder devices 33R and 33L are connected to the cylinder chambers 72 and 73 together with the left and right bearing housings 16R and 16L. One roll 11 is displaced (moved) in the roll gap increasing / decreasing direction (direction A).

The hydraulic cylinder devices 33R and 33L incorporate piston displacement meters 41R and 41L. The piston displacement meters 41R and 41L constitute second position detecting means for detecting (measuring) the piston positions of the hydraulic cylinder devices 33R and 33L. The piston displacement meters 41R and 41L are composed of incremental displacement meters that can easily obtain a higher resolution than the absolute displacement meters, and have a resolution higher than that of the linear scales 42R and 42L, for example, a resolution of about 0.5 μm Have

  Hydraulic pressure is supplied to the cylinder chambers 72, 73 of the hydraulic cylinder devices 33R, 33L by bidirectional hydraulic pumps 74R, 74L driven by servo motors 75R, 75L. The bidirectional hydraulic pumps 74R and 74L quantitatively control the amount of hydraulic pressure supplied to the cylinder chambers 72 and 73 according to the drive amount (rotation angle) by the servo motors 75R and 75L, and together with the hydraulic cylinder devices 33R and 33L, Servo type linear drive means.

  High-resolution incremental rotary encoders 78R and 78L for detecting the motor position (rotation angle) are connected to the servo motors 75R and 75L.

  In the bidirectional hydraulic pumps 74R and 74L, the value obtained by converting the pump volume per unit of its own control resolution into the piston movement amount of the hydraulic cylinder devices 33R and 33L is less than the mechanical resolution of the piston displacement meters 41R and 41L. The pump volume per rotation is set so that

  This is because when the resolution of the piston displacement meters 41R and 41L is 0.5 μm as the resolution required for position control and the mechanical control resolution (experience value) of the bidirectional hydraulic pumps 74R and 74L is 0.2 degrees, both The pump volume of the bidirectional hydraulic pumps 74R and 74L is set to the pump volume at which the piston movement amount of the hydraulic cylinder devices 33R and 33L is 0.5 μm or less when the directional hydraulic pumps 74R and 74L are rotated by 0.2 degrees. Means that.

A relational expression between the pump volume V (mm ³ ) of the bidirectional hydraulic pumps 74R and 74L satisfying this condition and the cylinder diameter D (mm) of the hydraulic cylinder devices 33R and 33L is expressed by the following expression.

^{V ≦ {(πD 2/4} ) a} / (b / 360)
However, a is the resolution (mm) of the piston displacement meters 41R and 41L, and b is the mechanical control resolution (degrees) of the bidirectional hydraulic pumps 74R and 74L.

The piston displacement meter 41R, 0.5 [mu] m resolution 41L, the bidirectional hydraulic pumps 74R, when the 0.2 degrees of mechanical control resolution of 74L, the V = 0.707D ^2.

  Thus, the piston position control can be performed with a resolution equal to or lower than the resolution of the piston displacement meters 41R and 41L by the control of the bidirectional hydraulic pumps 74R and 74L by the servo motors 75R and 75L.

  The hydraulic pipes 76R, 76L, 77R, 76L between the bidirectional hydraulic pumps 74R, 74L and the cylinder chambers 72, 73 of the hydraulic cylinder devices 33R, 33L are configured by flexible pipes such as flexible hoses.

  Since the hydraulic pipes 76R, 76L, 77R, and 76L are configured by flexible pipes, vibrations of the bidirectional hydraulic pumps 74R and 74L and the servo motors 75R and 75L are not easily transmitted to the hydraulic cylinder devices 33R and 33L. Therefore, a decrease in accuracy due to this vibration can be avoided. When the hydraulic pipes 76R, 76L, 77R, 76L are flexible pipes, the pipe length is preferably 3000 mm or less.

  The hydraulic pipes 76R, 76L, 77R, and 76L may be configured by high-pressure pipes having normal rigidity. In this case, the piping length is preferably 100 mm or more so that the vibrations of the bidirectional hydraulic pumps 74R and 74L and the servo motors 75R and 75L are not easily transmitted to the hydraulic cylinder devices 33R and 33L.

  The servo motors 75R and 75L are controlled by the control device 50 including the roll gap control unit 51.

  The control device 50 is of an electronic control type by a microcomputer, and sensor signals (measurement information) are respectively given from piston displacement meters 41R and 41L, linear scales 42R and 42L, load cells 43R and 43L, and rotary encoders 78R and 78L. The servo motors 75R and 75L are controlled at each sampling timing to control the roll gap between the first roll 11 and the second roll 12.

Roller gap control unit 51 is for controlling the roll value, as a viable control mode, the piston displacement meter 41R, 41L, the linear scale 42R, 42 first roll 11 by the measurement value by the L and the second roll 12 The roll gap constant control mode for adjusting the roll gap (roll position) so that the roll gap with the predetermined control target value and the measured load values of the load cells 43R and 43L cause the pressing load of the first roll 11 to be predetermined. Two feedback control modes of a constant pressing load control mode for adjusting the roll gap (roll position) so as to become the control target value are provided, and either one of the control modes is selectively executed.

  Basically, the roll gap constant control is performed by setting the roll gap control target value and the rolls of the first roll 11 and the second roll 12 measured by the piston displacement meters 41R and 41L or the linear scales 42R and 42L. The servo motors 75R and 75L are feedback-controlled so that the control deviation from the measured value of the gap (piston position, roll position) becomes zero, and the pressing load constant control is performed by setting the control target value of the pressing load and the load cell. The servomotors 75R and 75L are feedback-controlled so that the control deviation from the measured value of the pressing load of the first roll 11 measured by 43R and 43L becomes zero.

  In this embodiment, the roll gap constant control performs roll position control based on position information detected by the linear scales 42R and 42L when the roll gap control target value is changed (including when the roll is opened / closed). When the sheet is formed by the control target value, the roll position is controlled based on the position information detected by the piston displacement meters 41R and 41L.

  More specifically, when the control target value of the roll gap is changed, the linear scale 42R, until the deviation between the control target value after the change of the control target value and the roll position measurement value by the linear scales 42R, 42L becomes a predetermined value or less. When the roll position control is performed based on the position information detected by 42L, and the deviation between the control target value after the change of the control target value and the roll position measurement value by the linear scales 42R and 42L is equal to or less than a predetermined value, the piston displacement meter Roll position control is performed based on position information detected by 41R and 41L.

  Note that the roll position measurement by the linear scales 42R and 42L is continued during the roll position control based on the position information detected by the piston displacement meters 41R and 41L, and the position information detected by the piston displacement meters 41R and 41L. When the roll position greatly fluctuates due to disturbance or the like and the deviation between the control target value and the roll position measurement value by the linear scales 42R, 42L is not less than a predetermined value, the linear scale 42R, Roll position control based on the position information detected by 42L is performed.

  Any roll position control is performed by a position control command to the servo motors 75R and 75L. The position control of the servo motors 75R and 75L is feedback controlled by the motor positions of the servo motors 75R and 75L measured by the rotary encoders 78R and 78L. Done to the formula.

  Thus, when the roll position is changed, when the roll position is moved to the control target position, highly accurate position control using the linear scales 42R and 42L is performed, and the control target value after the control target value change and the linear scale 42R, After the deviation from the roll position measurement value by 42L becomes equal to or less than the predetermined value, sheet forming as a product is started, so that fluctuations in the roll gap due to inevitable fluctuation vibration in feedback control are detected by the piston displacement meters 41R and 41L. It is possible to stably produce high-quality sheets by keeping small ones with high resolution.

  In the above-described embodiment, the piston displacement meters 41R and 41L are used as the second position detecting means for detecting the position of the driving means. However, the second position detecting means is a motor of servo motors 75R and 75L. It can also be configured by incremental rotary encoders 78R and 78L for detecting the position.

  In the above-described embodiment, the hydraulic servo type is used as the linear drive means, but the linear drive means may be of a feed screw type driven by a servo motor. In this case, the second position detection means is constituted by an incremental rotary encoder that detects the motor position of a servo motor that rotationally drives the feed screw.

It is a lineblock diagram showing one embodiment of a sheet forming device by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fixed base 11 1st roll 12 2nd roll 13 3rd roll 16R, 16L Bearing housing 17R, 17L Linear guide 24R, 24L Bearing housing 27R, 27L Bearing housing 33R, 33L Hydraulic cylinder device 41R, 41L Piston displacement meter 42R, 42L linear scale 43R, 43L load cell 50 control device 51 roll clearance control unit 74R, 74L bidirectional hydraulic pump 75R, 75L servo motor 100 T die 110 extruder 111 screw 112 screw drive motor

Claims (8)

A sheet having two rolls arranged in parallel with a gap, passing a sheet between the two rolls that are rotationally driven, and performing sheet forming in a state where the front and back surfaces of the sheet are in contact with the two rolls In the molding equipment,
Linear drive means for adjusting the roll gap by moving at least one of the two rolls in the roll gap increase / decrease direction; and
First position detecting means for detecting a position of the roll in the roll gap increase / decrease direction;
A second position detection means for detecting a position of the linear drive means, having a resolution higher than that of the first position detection means ;
When the control target value of the roll gap is changed , roll position control is performed based on the position information detected by the first position detecting means, and when the sheet is formed by a predetermined control target value, the second position detecting means detects the roll position. Control means for performing roll position control based on the position information;
Sheet molding apparatus that have a. A sheet having two rolls arranged in parallel with a gap, passing a sheet between the two rolls that are rotationally driven, and performing sheet forming in a state where the front and back surfaces of the sheet are in contact with the two rolls In the molding equipment,
Linear drive means for adjusting the roll gap by moving at least one of the two rolls in the roll gap increase / decrease direction ; and
First position detecting means for detecting a position of the roll in the roll gap increase / decrease direction;
A second position detection means for detecting a position of the linear drive means, having a resolution higher than that of the first position detection means;
When changing the control target value of the roll gap, the first position detecting unit until the deviation between the control target value after the change of the control target value and the roll position measured value by the first position detecting unit becomes a predetermined value or less. Roll position control based on the position information detected by the control target value, when the deviation between the control target value after the control target value change and the roll position measurement value by the first position detection means is less than a predetermined value, Control means for performing roll position control based on position information detected by the second position detection means;
Sheet molding apparatus that have a. In the sheet forming apparatus according to claim 1 or 2 ,
A sheet forming apparatus in which the resolution of the second position detecting means is 0.5 μm or less . In the sheet forming apparatus according to any one of claims 1 to 3 ,
The first position detecting means is constituted by an absolute-type displacement gauge,
It said second position detecting means sheet forming apparatus that is composed by the incremental displacement meter. In the sheet forming apparatus according to any one of claims 1 to 4 ,
Said linear drive means is of a servohydraulic having a hydraulic cylinder device Before moving the roll in the roll gap decreasing direction, and a bi-directional hydraulic pump of the servo motor drive to control the hydraulic supply amount to be sent to the hydraulic cylinder device Yes,
The second position detecting means is constituted by a displacement meter that measures the position of the piston of the hydraulic cylinder device,
Per one rotation of the bidirectional hydraulic pump so that the value obtained by converting the pump volume per unit of the control resolution of the bidirectional hydraulic pump into the piston movement amount of the hydraulic cylinder device is less than the measurement resolution of the displacement meter. sheet forming apparatus pump volume of that set. The sheet forming device according to billed claim 5,
A sheet forming apparatus in which a pump volume V (mm ³ ) of the bidirectional hydraulic pump and a cylinder diameter D (mm) of the hydraulic cylinder device are set to satisfy the following relational expression .
^{V ≦ {(πD 2/4} ) a} / (b / 360)
However, a: Resolution (mm) of the displacement meter of the linear drive means, b: Mechanical control resolution (degree) of the bidirectional hydraulic pump The sheet forming device according to billed claim 6,
A sheet forming apparatus in which a mechanical control resolution b of the bidirectional hydraulic pump is 0.2 degrees . In the sheet forming apparatus according to any one of claims 5 to 7,
The sheet forming equipment are constituted by a pipe hydraulic pipes is flexible and bidirectional hydraulic pump and before Symbol hydraulic cylinder device.

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