WO2019031350A1 - Screw extruder with rollers - Google Patents

Abstract

This screw extruder provided with rollers (1) is provided with a screw (2, 3) which extrudes a material, a sleeve (4) which houses the screw (2, 3) and in which an injection orifice (12) of the material is located and a pair consisting of an upper roll (5) and a lower roll (6) which are located in front of the sheath (4) and which shape the extruded material by the screw (2). , 3) into a sheet, one of the upper roll (5) and the lower roll (6) having two end sections in the axial direction and a main body section between the two end sections and the section cross-section of the main body section perpendicular to the axial direction having an oval shape. <u /> <u />

Description

Roll screw extruder

The present invention relates to a roll screw extruder for extruding a material into a sheet.

An extruder is used in the manufacturing process of an automobile tire. The said extrusion molding machine is installed under the kneading machine which knead | mixes the rubber | gum which is a raw material of a tire, and shape | molds it in a sheet form, extruding continuously the rubber (material) thrown in from the said kneading machine. As a technique related to this type of extruder, for example, sheet forming apparatuses described in Patent Documents 1 and 2 below are known.

The sheet forming apparatus described in Patent Document 1 includes a conical twin-screw extruder and a pair of upper and lower rolling rolls disposed close to the tip opening of the twin-screw extruder. The diameter of the lower rolling roll of the pair of rolling rolls is larger than the diameter of the upper rolling roll.

In the sheet forming apparatus described in Patent Document 2, a material supply unit that extrudes and supplies a material, a material storage unit that temporarily stores the extruded material, and a material press that applies a pressing force to the stored material. And a material rolling unit that forms and discharges the stored material into a sheet. The above-described material supply unit includes a biaxial tapered screw, and the above-described material rolling unit includes a pair of upper and lower rolls.

Here, in the pair of rolls constituting the sheet forming apparatus described in Patent Documents 1 and 2, the shape of the cross section orthogonal to the axial direction is a circle.

In recent years, the demand for fuel-efficient tires has increased. In many cases, a high proportion of silica is compounded into rubber, which is a raw material of low fuel consumption tires. The rubber (material) which mix | blended the silica by a high ratio has the problem of being hard to shape | mold to a sheet form in an extrusion molding machine. Therefore, it is desirable to improve the dispersive mixing properties of the rubber (material) not only in the kneader of the upstream process but also in the extruder. That is, in addition to the sheet forming function of forming the material into a sheet, it is desired to add the kneading function of the material to the extruder.

However, the screw which comprises the sheet forming apparatus (extrusion molding machine) of patent documents 1 and 2 has only a function which extrudes material, and a roll has only a function which rolls material. That is, since neither the screw and the roll that constitute the sheet forming apparatus described in Patent Documents 1 and 2 have a kneading function of the material, in the sheet forming apparatus described in Patent Documents 1 and 2, the material is dispersed and mixed. I can not improve my sex.

Japanese Patent Laid-Open No. 6-64020 JP, 2011-73428, A

The present invention has been made in view of the above situation, and an object thereof is to provide a roll screw extruder having a kneading function of a material in addition to a sheet forming function of forming the material into a sheet. .

The roller screw extruder according to the present invention is for extruding a material into a sheet. The roll screw extruder includes a screw for extruding the material, a casing containing the screw, and a casing provided with an inlet for the material, disposed in front of the casing, the material extruded by the screw And a pair of upper and lower rolls formed into a sheet. One of the upper roll and the lower roll has axial end portions and a main body portion between the both end portions, and a cross section orthogonal to the axial direction of the main body portion has , Has an oval shape.

It is sectional drawing of the screw extruder with a roll which concerns on one Embodiment of this invention, and is the figure which looked at the said screw extruder with a roll from the top. It is a block diagram which shows the functional structure of the controller with which the screw extruder with a roll shown in FIG. 1 is provided. FIG. 3 is a cross-sectional view taken along line III-III in FIG. It is the figure which expanded the IV part of FIG. It is the schematic diagram which looked at the screw extruder with a roll which concerns on other embodiment of this invention from the side. The screw extruder with a roll shown in FIG. 5 WHEREIN: It is a graph which shows the relationship between the cumulative rotation speed of a roll, and the average pressure of a bank part. The screw extruder with a roll shown in FIG. 5 WHEREIN: It is a graph which shows the relationship between the rotation phase of a roll, and the clearance gap dimension of a roll. The screw extruder with a roll shown in FIG. 5 WHEREIN: It is a graph which shows the relationship between the fluctuation | variation of sheet | seat thickness, and the major axis length and minor axis length of the elliptical shape in the cross section of a roll. It is the schematic diagram which looked at the screw extruder with a roll which concerns on other embodiment of this invention from the side. It is the schematic diagram which looked at the screw extruder with a roll which concerns on other embodiment of this invention from the side. In the screw extruder with a roll shown in FIG. 10, it is a graph which shows the relationship between the fluctuation | variation of sheet | seat thickness, and the major axis length and minor axis length of elliptical shape in the cross section of a roll. It is a flowchart which shows an example of the control method of the screw extruder with a roll for stabilizing sheet | seat thickness. It is a flowchart which shows the other example of the control method of the screw extruder with a roll for stabilizing sheet | seat thickness. It is the schematic which shows an example of the cross-sectional shape of the roll in the screw extruder with a roll which concerns on the said embodiment. It is the schematic which shows the other example of the cross-sectional shape of the roll in the screw extruder with a roll which concerns on the said embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The screw extruder with a roll which concerns on this embodiment is a machine which extrusion-molds the kneaded material (material) of polymeric materials, such as rubber | gum, to a sheet form. In addition, the shaping | molding object of the screw extruder with a roll of this invention is not limited to rubber | gum, For example, other materials, such as a food material, are also included.

First, with reference to FIGS. 1 and 2, the basic configuration of the screw extruder with a roll according to the present embodiment and the main features of the present invention will be described. As shown in FIGS. 1 and 2, the screw extruder 2 with a roll according to the present embodiment accommodates the screws 2 and 3 for extruding the material, and the screws 2 and 3, and a casing 4 provided with the material inlet 12. And a pair of upper rolls 5 and lower rolls 6 which are disposed in front of the casing 4 and form the material extruded by the screws 2 and 3 into a sheet, and a controller 20. Between the casing 4 and the pair of rolls 5 and 6, a bank part 7 (material storage part) in which the material pushed out by the screws 2 and 3 is accumulated is provided. In the present embodiment, the direction from the screws 2 and 3 toward the pair of rolls 5 and 6 (for example, the left side in FIG. 1) is taken as the front.

The screw extruder with a roll of the present invention may include only a single screw for extruding a material, but the screw extruder with a roll 1 according to the present embodiment includes a pair of left and right screws 2 and 3 . The screws 2 and 3 each have a shaft portion 10 and a spiral flight portion 11 provided on the outer peripheral surface of the shaft portion 10. The screw 2 and the screw 3 have the same shape and the same dimensions except that the directions of the spirals of the flight portion 11 are opposite to each other. The screws 2 and 3 are connected to rotate in opposite directions to each other, and are configured to rotate at the same number of rotations by one driving means (not shown). The screws 2 and 3 may be configured to rotate individually by separate drive means.

The casing 4 has a tapered shape, and the top of the casing 4 is provided with a material inlet 12. The material (for example, a mixture of rubber and silica) supplied to the inlet 12 from above is pushed out to the bank 7 by the screws 2 and 3 rotating in opposite directions, and then between the rolls 5 and 6 It is formed into a sheet by passing through.

The material extruded by the screws 2 and 3 temporarily accumulates in the bank 7 (material reservoir) before reaching the pair of rolls 5 and 6.

The pair of rolls 5 and 6 are connected to rotate in opposite directions to each other, and are configured to rotate, for example, at the same number of rotations, by one driving means (not shown). The rolls 5 and 6 may be configured to be separately rotated by separate drive means. The rolls 5 and 6 are for rolling the material into a sheet (sheet 50) and may be called a roller die.

The upper roll 5 is supported by a support member (a member constituting a part of the roll screw extruder 1), which is not shown, so as to be rotatable about a rotation axis. The lower roll 6 is supported by the support member so as to be rotatable about the rotation axis. The upper roll 5 and the lower roll 6 are supported by the support member such that the axial direction of the rotation axis of the upper roll 5 and the axial direction of the rotation axis of the lower roll 6 are parallel. The upper roll 5 and the lower roll 6 are spaced apart in a direction (radial direction) perpendicular to the axial direction. The upper roll 5 has a main body portion 5a, both end portions 5b, and a pair of shaft portions 5c. Similarly, the lower roll 6 has a body portion 6a, both ends 6b, and a pair of shaft portions 6c.

The main body portion 5a of the upper roll 5 and the main body portion 6a of the lower roll 6 each have an outer peripheral surface (main outer peripheral surface) facing each other at an interval in the radial direction. These main body outer peripheral surfaces are portions for rolling the material extruded by the screws 2 and 3 into a sheet shape.

Both ends 5b of the upper roll 5 are constituted by a first end 5b and a second end 5b which are located on both outer sides in the axial direction with respect to the main body portion 5a of the upper roll 5. Both end portions 6b of the lower roll 6 are constituted by a first end 6b and a second end 6b which are located on both outer sides in the axial direction with respect to the main body portion 6a of the lower roll 6.

The first end 5 b of the upper roll 5 and the first end 6 b of the lower roll 6 each have an outer peripheral surface (end outer peripheral surface) facing each other at an interval in the radial direction. Similarly, the second end 5 b of the upper roll 5 and the second end 6 b of the lower roll 6 each have an outer peripheral surface (end outer peripheral surface) opposed to each other at an interval in the radial direction. The pair of end outer peripheral surfaces of the upper roll 5 are portions where the arc surfaces 13a of the pair of side guards 13 described later face in the radial direction, and the pair of end outer peripheral surfaces of the lower roll 6 will be described later The arc surfaces 13b of the pair of side guards 13 are portions facing in the radial direction (see FIGS. 1 and 4).

The pair of shaft portions 5c of the upper roll 5 is a portion supported by the support member such that the upper roll 5 can rotate. As shown in FIG. 1, the pair of shaft portions 5c is located on the outer side in the axial direction with respect to the first end portion 5b and the outer side in the axial direction with respect to the second end portion 5b. And a second shaft portion 5c located at In the upper roll 5, the outer diameter of the pair of shaft portions 5c is smaller than the outer diameter of the both end portions 5b. Similarly, the pair of shaft portions 6c of the lower roll 6 is a portion supported by the support member so that the lower roll 6 can rotate. The pair of shaft portions 6c is a first shaft portion 6c located outside in the axial direction with respect to the first end 6b, and a second shaft portion located outside in the axial direction with respect to the second end 6b. 6c. In the lower roll 6, the outer diameter of the pair of shaft portions 6c is smaller than the outer diameter of the both ends 6b.

In at least one of the upper roll 5 and the lower roll 6, a cross section orthogonal to the axial direction at least in the body portion has an oval shape. This configuration is the main feature of the present invention.

In the present embodiment, the cross section orthogonal to the axial direction of the main body portion 5a of the upper roll 5 and the cross section orthogonal to the axial direction of the main body portion 6a of the lower roll 6 have an oval shape. More specifically, in the cross section of the main body portion 5a of the upper roll 5, the portion (peripheral portion) corresponding to the outer peripheral surface of the main body portion 5a has an oval shape, and the cross section of the main body portion 6a of the lower roll 6 In the above, the portion (outer peripheral portion) corresponding to the outer peripheral surface of the main body portion 6a has an oval shape.

The main body portion 5a of the upper roll 5 is configured by the cross section having the oval shape being continuous in the axial direction. Similarly, the main body portion 6a of the lower roll 6 is configured by the cross section having the oval shape being continuous in the axial direction.

However, in the present invention, in at least one of the upper roll 5 and the lower roll 6, the cross section of the main body portion may have an oval shape. Therefore, only the cross section of the main body portion 5 a of the upper roll 5 may have an oval shape, and the cross section of the main body portion 6 a of the lower roll 6 may have a circular shape, for example. Alternatively, only the cross section of the main body portion 6 a of the lower roll 6 may have an oval shape, and the cross section of the main body portion 5 a of the upper roll 5 may have a circular shape, for example.

Here, the oval shape includes an egg shape, an oval shape, and an oval shape. In the present embodiment, the cross section of the body portions 5a and 6a of the rolls 5 and 6 has an oval shape among oval shapes, but may have an oval shape or an oval shape. As an egg shape, the shape as shown in FIG. 14 can be illustrated. The egg shape includes shapes such as a shape obtained by connecting an arc and an elliptic arc, and a shape obtained by connecting two elliptic arcs having different eccentricities. The oval shape is a shape similar to the track of the athletic field, as shown in FIG. 15, and includes two arcs (or elliptical arcs) and two parallel lines of parallel lines connecting these arcs (or elliptical arcs) And a shape consisting of As shown in FIGS. 14 and 15, each of the egg shape and the oval shape has a major axis LA and a minor axis SA.

In the present embodiment, in the main body portion of at least one of the upper roll 5 and the lower roll 6, the cross section orthogonal to the axial direction has an oval shape, so the upper roll 5 and the lower roll When 6 rotates, the volume of the bank part 7 (material storage part) between these rolls 5 and 6 and the casing 4 fluctuates. When the volume of the bank portion 7 changes, the flow of the material extruded from the casing 4 to the bank portion 7 becomes more complicated than before, and as a result, the material is given a kneading action. In the bank portion 7, a flow of material in the direction from the screws 2 and 3 to the rolls 5 and 6 is generated, but the volume of the bank portion 7 fluctuates. The material flow (back flow) towards 3 is induced in the bank section 7. As a result, the flow of the material extruded from the casing 4 to the bank portion 7 becomes more complicated than in the past.

The relative phase difference between the upper roll 5 and the lower roll 6 with respect to the rotation of the rolls 5 and 6 is not particularly limited, but the upper roll 5 and the lower roll 6 have a relative phase difference of 90 °. It is preferable to rotate. That is, it is preferable that the upper roll 5 and the lower roll 6 rotate at the same rotation speed so that the phase difference is maintained at 90 °. 3 and 4 show a state in which the phase difference between the upper roll 5 and the lower roll 6 is 90 °. When the upper roll 5 and the lower roll 6 rotate with a phase difference of 90 °, the variation in the dimension of the gap (roll gap dimension) between the roll 5 and the roll 6 is minimized, and as a result, the thickness of the sheet 50 Fluctuation is reduced. As a result, the thickness of the sheet 50 extruded from between the rolls 5 and 6 can be further stabilized (fixed).

The phase difference is, as shown in FIG. 4, the major axis of the oval shape (elliptical in FIG. 4) of the cross section orthogonal to the axial direction in the main body portion 5 a of the upper roll 5 and the main body portion of the lower roll 6 It is defined by an angle formed by the major axis of the oval shape (elliptic in FIG. 4) of the cross section orthogonal to the axial direction in 6a.

As shown in FIGS. 3 and 4, in the present embodiment, in order to prevent the material stored in the bank portion 7 from leaking to the outside in the axial direction with respect to the main body portions 5a, 6a of the rolls 5, 6, The cross sections of both ends 5b, 6b of the rolls 5, 6 have a circular shape. More specifically, in the cross section of the both ends 5 b of the upper roll 5, the portion (peripheral part) corresponding to the outer peripheral surface of the both ends 5 b has a circular shape, and the above in the both ends 6 b of the lower roll 6 Of the cross section, the portion (peripheral portion) corresponding to the outer peripheral surface of the both end portions 6 b has a circular shape. The cross section of the main body portion 5a, 6a between the end portions 5b, 6b has an oval shape (elliptical shape in the present embodiment) as described above. Thus, the cross-sectional shape of both ends 5 b and 6 b of the upper roll 5 and the lower roll 6 is a circle, and at least one of the upper roll 5 and the lower roll 6 (in the present embodiment, both rolls 5 , 6), the cross-sectional shape of the main body portions 5a, 6a is preferably oval.

As shown in FIGS. 1, 3 and 4, the roll screw extruder 1 includes a pair of side guards 13. The pair of side guards 13 are provided to prevent the material stored in the bank portion 7 from leaking to the outside in the axial direction more than the main body portions 5 a and 6 a of the rolls 5 and 6. As shown in FIG. 1, the pair of side guards 13 are arranged at intervals in the axial direction. As shown in FIGS. 1 and 3, the pair of side guards 13 is disposed between the casing 4 and the pair of rolls 5 and 6.

As shown in the enlarged view of FIG. 4, each of the pair of side guards 13 has a proximal end (rear end) connected to the casing 4 and a distal end (front end) opposite to the pair of rolls 5 and 6 And. The front end of one side guard 13 is an arc surface 13 a facing the first end 5 b of the both ends 5 b of the upper roll 5 and a first end 6 b of the both ends 6 b of the lower roll 6. And an opposite arc surface 13b. The tip end of the other side guard 13 is an arc surface 13 a facing the second end 5 b of the both ends 5 b of the upper roll 5 and a second end 6 b of the both ends 6 b of the lower roll 6. And an opposite arc surface 13b.

In the present embodiment, each of the pair of side guards 13 has a plate-like shape orthogonal to the axial direction, but the material stored in the bank 7 is more than the body portions 5 a, 6 a of the rolls 5, 6. The shape of the side guard 13 is not limited to a plate-like shape, as long as it can prevent leakage to the outside in the axial direction. The inner wall surface of one side guard 13 and the inner wall surface of the other side guard 13 face each other at an interval in the axial direction, and constitute a part of the inner wall surface that divides the bank portion 7.

When the cross sectional shapes of both ends 5b, 6b of the rolls 5, 6 are circular, in other words, when the both ends 5b, 6b of the rolls 5, 6 are cylindrical, when the rolls 5, 6 are rotated. The gap between the both ends 5b, 6b and the arc surface 13a, 13b (see FIGS. 3 and 4) of the side guard 13 can be maintained at a constant gap size (constant small gap size). As a result, the leakage of the material from the bank portion 7 as described above can be prevented.

As shown in FIG. 3 and FIG. 4, the screw extruder with a roll 1 of this embodiment includes a pressure sensor 8 for measuring the pressure of the bank 7 (the material in the bank 7), a pair of rolls 5, And a thickness sensor 9 for measuring the thickness of the sheet-like material (sheet 50) extruded from between six. The pressure sensor 8 and the thickness sensor 9 are used for control to reduce the variation of the thickness of the sheet 50 (details will be described later). In the roll screw extruder 1, at least one of the pressure sensor 8 and the thickness sensor 9 is preferably provided, but the pressure sensor 8 and the thickness sensor 9 are not essential in the roll screw extruder 1, It can be omitted.

The controller 20 includes a central processing unit (CPU), a ROM that stores various control programs, and a RAM that is used as a work area of the CPU. As shown in FIG. 2, the controller 20 has a screw control unit 20a, a roll control unit 20b, a storage unit 20c, and a determination unit 20d as functions.

The screw control unit 20 a controls the number of rotations of the screws 2 and 3. The roll control unit 20 b controls the number of rotations of the rolls 5 and 6. The storage unit 20 c stores information on the pressure measured by the pressure sensor 8. The storage unit 20 c also stores information on the sheet thickness measured by the thickness sensor 9. The determination unit 20 d compares a value related to the pressure measured by the pressure sensor 8 with a threshold related to the pressure set in advance, and determines whether these satisfy the predetermined condition. Further, the determination unit 20 d compares the value regarding the sheet thickness measured by the thickness sensor 9 with the threshold value regarding the sheet thickness set in advance, and determines whether or not these meet the predetermined condition.

FIG. 5 shows another embodiment of a pair of rolls 5, 6. In the roll screw extruder 1 shown in FIGS. 1 and 2, the lower roll 6 is slightly larger than the upper roll 5. On the other hand, in the screw extruder with a roll 102 shown in FIG. 5, the cross sections of the main body portions 5a and 6a of the upper roll 5 and the lower roll 6 have the same shape and oval shape (the same circumferential length) In the embodiment, it has an elliptical shape). That is, the upper roll 5 and the lower roll 6 have exactly the same shape and dimensions. According to this configuration, there is an advantage that control of the number of rotations of the rolls 5 and 6 becomes easy. For example, when the rolls 5 and 6 have different shapes, an event occurs in which the inflow of material on the upstream side of each roll and the outflow of the material on the downstream greatly change in time series, which is uniform Control to realize the inflow and outflow of various materials. When the rolls 5 and 6 have the same shape, it is easy to avoid the above-mentioned events and to control them easily.

Here, FIG. 6 is a graph showing a change in average bank portion pressure due to roll rotation in the roll screw extruder 102 shown in FIG. The horizontal axis in FIG. 6 is the cumulative number of revolutions of the roll, and the vertical axis is the average pressure in the bank portion 7. In addition, the data of the "conventional shape" shown in FIG. 6 are data in the case where the cross sections of the upper and lower rolls are both circular. Further, rubber was used as the material to be molded (the same applies to FIGS. 8 and 11 described later for the material to be molded).

As can be seen from FIG. 6, when the cross sections of the upper and lower rolls both have the conventional shape (circular shape), the pressure of the bank portion 7 does not change. On the other hand, when the cross sections of the main body portions 5a and 6a of the upper roll 5 and the lower roll 6 have an elliptical shape as in the embodiment shown in FIG. 5, the pressure of the bank 7 fluctuates.

In the case of the conventional shape, the extrusion amount of the material from the screws 2 and 3 and the outflow amount of the material from between the rolls are substantially the same. On the other hand, when the cross section of the main body portions 5a and 6a of at least one of the upper roll 5 and the lower roll 6 has an oval shape (e.g., an oval shape), the balance between the extrusion amount and the outflow amount Break down. Specifically, when the amount of outflow is smaller than the amount of extrusion, backflow of material occurs in the bank portion 7. On the other hand, when the outflow amount is larger than the extrusion amount, the forward flow of material (flow in the direction from the screws 2 and 3 to the rolls 5 and 6) in the bank portion 7 becomes strong. As a result, the flow of material in the bank section 7 becomes more complicated than before.

FIG. 7 is a graph showing the relationship between the roll rotational phase and the roll gap dimension in the roll screw extruder 102 shown in FIG. The horizontal axis in FIG. 7 is the rotational phase of the roll, and indicates the progress stage while the rolls 5 and 6 make one rotation (360 ° rotation). The vertical axis in FIG. 7 indicates the dimension of the gap between the opposing rolls 5 and 6. The analysis conditions for obtaining the results shown in the graph of FIG. 7 are as follows. That is, in the analysis, the length of the minor axis SA (see FIG. 5) of the ellipse, which is a cross-sectional shape orthogonal to the axial direction in the body portions 5a and 6a of the rolls 5 and 6, is 90 mm, and the major axis LA (see FIG. 5) The length of 100 mm) was 100 mm, and the condition was that the upper roll 5 and the lower roll 6 were rotated with a phase difference of 90 °. As can be seen from FIG. 7, when the cross-sectional shapes of the main body portions 5 a and 6 a of the upper roll 5 and the lower roll 6 are oval (oval shape), the roll gap dimensions change when the rolls 5 and 6 are rotated. Do.

Variations in roll gap dimensions affect the thickness of the sheet-like material (sheet 50) extruded from between the rolls 5,6. That is, in the present embodiment, the cross-sectional shape of the main portion of at least one of the upper roll 5 and the lower roll 6 is oval (oval), so that the flow of material in the bank 7 becomes complicated. The effect of kneading can be imparted to the material in the bank portion 7. On the other hand, in the present embodiment, the thickness of the sheet-like material (sheet 50) extruded from between the rolls 5 and 6 is more likely to be changed as compared to the case where the cross-sectional shapes of both rolls are circular. Therefore, the inventors of the present invention, as described below, the cross section of the roll (for suppressing the sheet thickness fluctuation) for reducing the thickness fluctuation of the sheet 50 extruded from between the rolls 5 and 6 We also examined the shape.

FIG. 8 shows the variation of the thickness of the sheet 50 extruded from the gap between the rolls 5 and 6 and the length of an elliptical shape which is the shape of the cross section of the rolls 5 and 6 in the screw extruder with roll 102 shown in FIG. It is a graph which shows the relationship between the length b of the axis LA and the length a of the short axis SA. The horizontal axis in FIG. 8 indicates the length b (mm) of the major axis LA of the ellipse which is the sectional shape of the rolls 5 and 6, and the vertical axis indicates the length a (mm) of the minor axis SA of the ellipse. ing.

In FIG. 8, the straight line represented by the equation “a = 0.939b-4.14” is such that the variation of the thickness of the sheet 50 is within a range of ± 10% with respect to the average thickness of the sheet 50. It is a straight line showing the relation between the length b (mm) of the major axis LA and the length a (mm) of the minor axis SA. Further, in FIG. 8, the straight line represented by the equation “a = 0.957b−2.95” is such that the variation of the thickness of the sheet 50 is within the range of ± 5% with respect to the average thickness of the sheet 50. It is a straight line showing the relation between the length b (mm) of the major axis LA and the length a (mm) of the minor axis SA in the case.

Here, for example, in the case where the material is rubber, regarding the sheet thickness, it is preferable that the variation be as small as possible in consideration of the influence on the downstream process. Specifically, it is preferable that the thickness variation is within ± 10% of the average thickness. In addition, it is more preferable that the thickness variation is within about 5% of the average thickness.

From FIG. 8, the relationship between the length a (mm) of the minor axis SA and the length b (mm) of the major axis LA is a condition represented by the inequality “0.939 b−4.14 ≦ a <b”. When satisfied, sheet thickness variation can be suppressed to within ± 10%. Moreover, when the relationship between the length a (mm) of the minor axis SA and the length b (mm) of the major axis LA satisfies the condition represented by the inequality expression “0.957 b−2.95 ≦ a <b” And sheet thickness fluctuation can be suppressed to within ± 5%.

That is, when the cross-sectional shape of the rolls 5 and 6 is an ellipse, the relationship between the length a of the minor axis SA and the length b of the major axis LA is an inequality expression “0.939b−4.14 ≦ a <b”. It is preferable to satisfy the condition indicated by Furthermore, it is more preferable that the relationship between the length a of the minor axis SA and the length b of the major axis LA satisfy the condition represented by the inequality “0.957b−2.95 ≦ a <b”. In the case of “a = b”, the cross-sectional shape of the rolls 5 and 6 is a circle, and the roll does not have a kneading function, so the case of “a = b” is excluded.

FIG. 9 shows yet another embodiment of a pair of rolls 5, 6. In the screw extruders with rolls 1 and 102 shown in FIGS. 3 and 5, the cross sections of the upper roll 5 and the lower roll 6 have an oval shape (elliptical shape) of the same shape. On the other hand, in the screw extruder with roll 103 shown in FIG. 9, the cross sections of the upper roll 5 and the lower roll 6 both have an oval shape (elliptical shape). The oval shapes (elliptical shapes) are different from each other. That is, in the screw extruder with roll 103 shown in FIG. 9, the ratio of the short axis SA to the long axis LA of the upper roll 5 and the ratio of the short axis SA to the long axis LA of the lower roll 6 are different.

Here, the rolls 5 and 6 of the screw extruder with a roll 102 shown in FIG. 5 and the rolls 5 and 6 of the screw extruder with a roll 103 shown in FIG. Have. It is the perimeter of the ellipse. In the screw extruder with roll 103 shown in FIG. 9, the circumferential length L of the main body portion 5a of the upper roll 5 and the main body portion 6a of the lower roll 6 as in the case of the screw extruder with roll 102 shown in FIG. The perimeter L is the same. When the cross-sectional shapes of the main body portions 5a and 6a of the upper roll 5 and the lower roll 6 are oval shapes having the same circumferential length (elliptical shape in the present embodiment), the control of the rotational speed of the rolls 5 and 6 is easy It has the merit of

Next, FIG. 10 shows still another embodiment of a pair of rolls 5 and 6. In any of the above-described embodiments, the cross-sections of the main body portions 5a and 6a of both the upper and lower rolls 5 and 6 have an oval shape (elliptical shape). On the other hand, in the roll screw extruder 104 shown in FIG. 10, the cross section of the main body portion 5a of the upper roll 5 has an oval shape (elliptical shape), but the cross section of the main body portion 6a of the lower roll 6 is circular Have.

As shown in FIG. 10, when the cross-sectional shape of the main body of one of the upper roll 5 and the lower roll 6 is an oval, and the cross-sectional shape of the main body of the other roll is a circle, The following effects can be obtained. In this configuration, the volume change of the bank portion 7 becomes large, as a result, the kneading of the material is promoted, and the kneading performance of the roll screw extruder is further improved. In addition, since the pressure-increased portion unevenly distributed in the lower roll 6 having a circular cross-sectional shape is generated by being dispersed on the lower roll 6, local abrasion of the roll can also be suppressed.

Here, in the screw extruder with roll 104 shown in FIG. 10, the circumferential length L of the main body portion 5a of the upper roll 5 and the circumference of the main body portion 6a of the lower roll 6 in order to suppress local abrasion of the roll. The length L is made different. In this case, the rotational speed of each of the upper roll 5 and the lower roll 6 is controlled to be different. The rotation speed of the lower roll 6 is constant, but the rotation speed of the upper roll 5 is relatively low when the lower roll 6 and the upper roll 5 are close to each other, and is relatively high speed otherwise. It is assumed. When the circumferential length L of the upper roll and the circumferential length L of the lower roll are different, in each of the rolls 5 and 6, the opposing portion (pressure-boosting portion) between the rolls 5 and 6 changes due to the rotation of the rolls. As a result, the forces acting from the material on the rolls 5 and 6 are dispersed, so that local wear of the rolls is suppressed. The circumferential length L of the main body portion 5 a of the upper roll 5 and the circumferential length L of the main body portion 6 a of the lower roll 6 may be the same.

FIG. 11 shows the variation of the thickness of the sheet 50 extruded from the gap between the rolls 5 and 6 and the major axis length of the oval shape in the roll cross section of the upper roll 5 in the roll screw extruder 104 shown in FIG. And a graph showing the relationship with the minor axis length. The horizontal axis of FIG. 11 indicates the length b (mm) of the major axis LA of the ellipse which is the sectional shape of the upper roll 5, and the vertical axis indicates the length a (mm) of the minor axis SA of the ellipse. There is.

The straight line represented by the equation “a = b−0.952” in FIG. 11 is the long axis in the case where the variation of the thickness of the sheet 50 is within ± 10% of the average thickness of the sheet 50. It is a straight line showing the relationship between the length b (mm) of LA and the length a (mm) of the short axis SA. Further, the straight line represented by the equation “a = b−0.488” is the long axis LA in the case where the variation of the thickness of the sheet 50 is within the range of ± 5% with respect to the average thickness of the sheet 50. It is a straight line which shows the relation between length b (mm) and length a (mm) of minor axis SA. In FIG. 11, the straight line represented by the formula “a = b−0.952” and the straight line represented by the formula “a = b−0.488” are very close to each other.

As described above, when the material is, for example, rubber, the thickness variation of the sheet thickness is within ± 10% of the average thickness, considering the influence on the downstream process. Preferably, it is more preferable that the thickness variation is within ± 5% of the average thickness.

From FIG. 11, when the relationship between the length a (mm) of the minor axis SA and the length b (mm) of the major axis LA satisfies the condition represented by the inequality “b−0.952 ≦ a <b” And sheet thickness fluctuation can be suppressed within ± 10%. If the relationship between the length a (mm) of the minor axis SA and the length b (mm) of the major axis LA satisfies the condition represented by the inequality “b−0.488 ≦ a <b”, the sheet Variation of thickness can be suppressed within ± 5%.

That is, when the cross-sectional shape of one roll is an ellipse and the cross-sectional shape of the other roll is a circle, the relationship between the length a of the minor axis SA of the ellipse and the length b of the major axis LA is It is preferable to satisfy the condition represented by the inequality “b−0.952 ≦ a <b”. Furthermore, the relationship between the length a of the minor axis SA and the length b of the major axis LA more preferably satisfies the condition represented by the inequality “b−0.488 ≦ a <b”. In the case of “a = b”, the shape of the cross section of the roll (the cross section of the upper roll 5) is a circle, and a combination of rolls having no kneading function (a combination of rolls that both rolls have a circular cross section) Since it is), it is excluded in the case of "a = b".

Next, in the roll screw extruder according to the present embodiment, a control method for reducing the variation of the thickness of the sheet 50 extruded from the gap between the rolls 5 and 6 (to suppress the variation of the sheet thickness) Control method) will be described using two specific examples.

First, a first control example will be described with reference to FIG. FIG. 12 is a flow chart showing an example of a control method of the screw extruder with a roll 1 for stabilizing the sheet thickness. In the control shown in FIG. 12, the pressure of the bank unit 7 is used as a determination reference.

As shown in FIG. 12, when the material is put into the casing 4 (step S1), the screw control unit 20a of the controller 20 controls the driving means to rotate the screws 2 and 3 (step S2). Thus, the material is sent to the bank section 7. The determination unit 20d of the controller 20 determines whether or not the measurement value of the pressure sensor 8 is equal to or greater than a predetermined value P1 (a preset threshold) (step S3). When the pressure in the bank 7 measured by the pressure sensor 8 is less than the predetermined value P1, it means that the bank 7 is not sufficiently filled with the material. Therefore, when the measurement value of the pressure sensor 8 is less than the predetermined value P1 (NO in step S3), the screw control unit 20a controls the drive unit to increase the number of rotations of the screws 2 and 3 (step S4). On the other hand, when the pressure in the bank 7 measured by the pressure sensor 8 is equal to or higher than the predetermined value P1 (YES in step S3), the roll control unit 20b of the controller 20 controls the driving unit to perform the roll. 5. Rotate 5 and 6 (step S5). As the rolls 5 and 6 rotate, the sheet-like material (sheet 50) is sequentially extruded from the gap between the rolls 5 and 6.

Here, in order to reduce the variation in the thickness of the sheet 50 extruded from the gap between the rolls 5 and 6, the controller 20 controls the maximum pressure Pmax and the minimum pressure Pmin within a predetermined time measured by the pressure sensor 8. The number of rotations of the screws 2 and 3 is controlled so that the difference .DELTA.P of the difference .DELTA.P becomes equal to or less than a predetermined value .DELTA.P1 (preset threshold). The predetermined time may be set to, for example, the time for which the rolls 5 and 6 make one rotation, but is not limited thereto. The pressure in the bank 7 (the pressure of the material in the bank 7) correlates with the thickness of the sheet 50. By including the fluctuation range of the pressure in the bank portion 7 (the above ΔP) within a predetermined range, the fluctuation of the thickness of the sheet 50 is reduced (the fluctuation of the sheet thickness is suppressed).

Specifically, the storage unit 20c of the controller 20 stores, for example, the maximum pressure Pmax and the minimum pressure Pmin measured by the pressure sensor 8 while the rolls 5 and 6 make one revolution (step S6). Then, the determination unit 20d determines whether the difference ΔP between the maximum pressure Pmax and the minimum pressure Pmin is larger than the predetermined value ΔP1 (step S7). If the difference ΔP is larger than the predetermined value ΔP1 (YES in step S7), the screw control unit 20a controls the drive unit to reduce the number of rotations of the screws 2 and 3 (step S8). This makes it possible to include the fluctuation range of the pressure in the bank portion 7 within a predetermined range, thereby reducing the fluctuation of the thickness of the sheet 50 (suppressing the fluctuation of the sheet thickness). it can.

When the operation is continued for a while, the amount of material in the bank 7 is reduced, so that a cavity is formed in the bank 7 and the fluctuation of the pressure in the bank 7 may increase again. In order to suppress the fluctuation of the pressure, the controller 20 makes the difference ΔP between the maximum pressure Pmax and the minimum pressure Pmin within the predetermined time measured by the pressure sensor 8 be less than or equal to a predetermined value ΔP2 (preset threshold). Control the number of revolutions of the rolls 5 and 6 in the same manner. The predetermined value ΔP2 is set to a value smaller than the predetermined value ΔP1. Moreover, although the said predetermined time can be set to the time which the rolls 5 and 6 make 1 rotation, for example, it is not restricted to this.

Specifically, when the difference ΔP is equal to or less than the predetermined value ΔP1 (NO in step S7), the determination unit 20d determines the maximum pressure measured by the pressure sensor 8 while the rolls 5 and 6 make one revolution. It is determined whether the difference ΔP between Pmax and the minimum pressure Pmin is larger than the predetermined value ΔP2 (step S9). If the difference ΔP is larger than the predetermined value ΔP2 (YES in step S9), the roll control unit 20b controls the driving unit to reduce the number of rotations of the rolls 5 and 6 (step S10). When the number of revolutions of the rolls 5 and 6 decreases, the material in the bank 7 is filled, and the pressure fluctuation in the bank 7 is reduced. Thereby, the variation of the thickness of the sheet 50 can be reduced (the variation of the sheet thickness can be suppressed).

The storage unit 20c stores the maximum pressure Pmax per one roll rotation and the minimum pressure Pmin (step S11), and the determination unit 20d performs the determination of step S9 again. When the difference ΔP is equal to or less than the predetermined value ΔP2 (NO in step S9) and the measurement value of the pressure sensor 8 is less than the predetermined value P2 (YES in step S12), the material supply to the bank portion 7 Since the amount is reduced, the controller 20 returns to the process of step S4, and the screw control unit 20a controls the drive means again to increase the number of rotations of the screws 2 and 3. On the other hand, when the measured value of the pressure sensor 8 is equal to or more than the predetermined value P2 (NO in step S12), the controller 20 performs the process of step S5 again.

Next, a second control example will be described with reference to FIG. FIG. 13 is a flow chart showing an example of a control method of the screw extruder with a roll 1 for stabilizing the sheet thickness. In the control shown in FIG. 13, the thickness of the material (sheet 50) formed into a sheet shape by being pushed out from the gap between the rolls 5 and 6 is used as a determination reference.

A part of the control flow shown in FIG. 12 and a part of the control flow shown in FIG. 13 are common. Therefore, in the control flow shown in FIG. 13, the description of the same steps as the steps shown in FIG. 12 will be omitted, and the steps different from the steps shown in FIG. 12 will be mainly described.

The steps S1 to S5 shown in FIG. 13 are the same as the steps S1 to S5 shown in FIG. In the control shown in FIG. 13, the controller 20 measures the thickness sensor 9 in steps S6 to S8 in order to reduce variations in the thickness of the sheet 50 extruded from the gap between the rolls 5 and 6. The number of rotations of the screws 2 and 3 is controlled such that the difference ΔT between the maximum sheet thickness Tmax and the minimum sheet thickness Tmin within a predetermined time is equal to or less than a predetermined value ΔT1 (preset threshold). The predetermined time may be set to, for example, the time for which the rolls 5 and 6 make one rotation, but is not limited thereto. In the second control example, since the thickness of the sheet 50 is used as the determination reference, the correlation between the control and the sheet thickness is high. Therefore, the variation of the thickness of the sheet 50 can be further reduced (the variation of the sheet thickness can be further suppressed).

Specifically, the storage unit 20c stores, for example, the maximum sheet thickness Tmax and the minimum sheet thickness Tmin measured by the thickness sensor 9 while the rolls 5 and 6 make one rotation (step S6). Then, the determination unit 20d determines whether the difference ΔT between the maximum sheet thickness Tmax and the minimum sheet thickness Tmin is larger than the predetermined value ΔT1 (step S7). If the difference ΔT is larger than the predetermined value ΔT1 (YES in step S7), the screw control unit 20a controls the driving means to reduce the number of rotations of the screws 2 and 3 (step S8). As a result, the difference ΔT in the sheet thickness can be reduced, and the variation in the thickness of the sheet 50 can be reduced (the variation in the sheet thickness can be suppressed).

When the operation is continued for a while, the amount of material in the bank 7 is reduced, so that a cavity may be formed in the bank 7 and the pressure fluctuation in the bank 7 may increase. This causes sheet thickness variations. In order to directly suppress the sheet thickness fluctuation, the controller 20 sets the difference ΔT between the maximum sheet thickness Tmax and the minimum sheet thickness Tmin within a predetermined time measured by the thickness sensor 9 to a predetermined value ΔT2. The number of rotations of the rolls 5 and 6 is controlled so as to be equal to or less than (a preset threshold). The predetermined value ΔT2 is set to a value smaller than the predetermined value ΔT1. Moreover, although the said predetermined time can be set to the time which the rolls 5 and 6 make 1 rotation, for example, it is not restricted to this.

Specifically, when the difference ΔT is equal to or smaller than the predetermined value ΔT1 (NO in step S7), the determination unit 20d determines the maximum measured by the thickness sensor 9 while the rolls 5 and 6 make one revolution. It is determined whether the difference ΔT between the sheet thickness Tmax and the minimum sheet thickness Tmin is larger than the predetermined value ΔT2 (step S9). If the difference ΔT is larger than the predetermined value ΔT2 (YES in step S9), the roll control unit 20b controls the driving means to reduce the number of rotations of the rolls 5 and 6 (step S10). When the number of revolutions of the rolls 5 and 6 decreases, the material in the bank 7 is filled, and the pressure fluctuation in the bank 7 is reduced. Thereby, the variation of the thickness of the sheet 50 can be reduced (the variation of the sheet thickness can be suppressed).

The storage unit 20c stores the maximum sheet thickness Tmax and the minimum sheet thickness Tmin per roll rotation (step S11), and the determination unit 20d performs the determination of step S9 again. When the difference ΔT is equal to or less than the predetermined value ΔT2 (NO in step S9) and the measurement value of the pressure sensor 8 is less than the predetermined value P2 (YES in step S12), the material supply to the bank portion 7 Since the amount is reduced, the controller 20 returns to the process of step S4, and the screw control unit 20a controls the drive means again to increase the number of rotations of the screws 2 and 3. On the other hand, when the measured value of the pressure sensor 8 is equal to or more than the predetermined value P2 (NO in step S12), the controller 20 performs the process of step S5 again.

As explained above, in addition to the sheet forming function which forms a material in a sheet form, the screw extruder with a roll which has the kneading function of material is provided.

The provided roll screw extruder is for extruding the material into a sheet. The roll screw extruder includes a screw for extruding the material, a casing containing the screw, and a casing provided with an inlet for the material, disposed in front of the casing, the material extruded by the screw And a pair of upper and lower rolls formed into a sheet. One of the upper and lower rolls has its axial ends and a body portion between the ends. The cross section perpendicular to the axial direction in the body portion has an oval shape.

According to this roll screw extruder, in the main body portion of at least one of the upper roll and the lower roll, the cross section orthogonal to the axial direction has an oval shape, so that the upper roll and the lower side As the rolls rotate, the volume of the material reservoir provided between the rolls and the casing fluctuates. As the volume of the material reservoir fluctuates, the flow of material extruded from the casing into the material reservoir becomes more complicated than in the past, and as a result, a kneading action is imparted to the material. That is, the said screw extruder with a roll has a kneading function of material in addition to the sheet forming function which forms material in a sheet form.

In the screw extruder with a roll, the oval shape may be elliptical.

In the roll screw extruder, the other roll of the upper roll and the lower roll has both axial end portions and a main body portion between the both end portions, and the other roll The cross section orthogonal to the axial direction in the main body portion may have an oval shape having the same shape and the same circumferential length as the cross section in the main body portion of the one roll. In this aspect, since the cross section of one roll and the cross section of the other roll are both oval shapes, the flow state of the material in the material reservoir can be adjusted by adjusting the phase difference between the one roll and the other roll. Can be adjusted. That is, in this aspect, the range in which the flow state of the material in the material storage portion can be adjusted is larger than in the case where the cross section in one roll is oval and the cross section in the other roll is circular.

When the cross section of one roll and the cross section of the other roll both have an oval shape, the upper roll and the lower roll have a phase difference of 90 ° between the upper roll and the lower roll. It is preferable to be configured to rotate in the following condition. In this aspect, the variation in the dimension of the gap (roll gap dimension) between one roll and the other is minimized, and as a result, the variation in the thickness of the sheet is reduced. This can further stabilize the thickness of the sheet extruded from between the upper roll and the lower roll.

When the cross section of one roll and the cross section of the other roll both have an oval shape and the upper roll and the lower roll rotate with a phase difference of 90 °, the oval shape is an ellipse, It is preferable that the length a (mm) of the minor axis of the ellipse and the length b (mm) of the major axis of the ellipse satisfy the relationship of 0.939b-4.14 ≦ a <b. This aspect allows the variation of the thickness of the sheet to the average thickness of the sheet to be included within the range of ± 10%. Furthermore, it is more preferable that the length a of the minor axis and the length b of the major axis satisfy the relationship of 0.957b-2.95 ≦ a <b. This aspect allows the variation of the thickness of the sheet to the average thickness of the sheet to be included within the range of ± 5%.

In the roll screw extruder, the other roll of the upper roll and the lower roll has both axial end portions and a main body portion between the both end portions, and the other roll The cross section orthogonal to the axial direction in the main body portion may have a circular shape. In this aspect, the volume fluctuation of the material reservoir becomes large, and as a result, kneading of the material is promoted.

In the roll screw extruder, the circumferential length of the main body portion of the upper roll and the circumferential length of the main body portion of the lower roll may be different.

When the cross section of one roll is an oval and the cross section of the other roll is a circle, the oval shape is an ellipse, and the minor axis length a (mm) of the ellipse The length b (mm) of the major axis of the ellipse preferably satisfies the following relationship: b−0.952 ≦ a <b. This aspect allows the variation of the thickness of the sheet to the average thickness of the sheet to be included within the range of ± 10%. Furthermore, it is more preferable that the length a of the minor axis and the length b of the major axis satisfy the relationship of b−0.488 ≦ a <b. This aspect allows the variation of the thickness of the sheet to the average thickness of the sheet to be included within the range of ± 5%.

In the roll screw extruder, the cross section orthogonal to the axial direction at the both end portions of the one roll has a circular shape, and the other roll of the upper roll and the lower roll has an axis thereof It is preferable that a cross section perpendicular to the axial direction of the other end of the other roll has a circular shape, having both end portions in the direction and a main body portion between the both ends. In this aspect, when the upper roll and the lower roll are rotated, between the outer circumferential surfaces of both ends of each roll and the arc surface of the side guard disposed to face the both ends in the radial direction. Is always maintained at a fixed size (a fixed small gap size). As a result, leakage of material from the material storage portion can be prevented.

In the roll screw extruder, a material storage portion is formed between the casing and the pair of upper and lower rolls, in which the material extruded by the screw is collected, and the roll screw extruder is And a pressure sensor for measuring the pressure of the material reservoir, and a difference between a maximum pressure and a minimum pressure within a predetermined time measured by the pressure sensor is equal to or less than a preset threshold value. It is preferable to further have a screw control unit that controls This aspect makes it possible to reduce sheet thickness variations.

In the roll screw extruder, a material storage portion is formed between the casing and the pair of upper and lower rolls, in which the material extruded by the screw is collected, and the roll screw extruder is A pressure sensor for measuring the pressure in the material storage section, and the number of revolutions of the roll so that the difference between the maximum pressure and the minimum pressure within a predetermined time measured by the pressure sensor is equal to or less than a preset threshold. It is preferable to further have a roll control unit to control. This aspect makes it possible to reduce sheet thickness variations.

The roll screw extruder has a thickness sensor for measuring the thickness of a sheet-like material extruded from between the pair of upper and lower rolls, and a maximum within a predetermined time measured by the thickness sensor. It is preferable to further include a screw control unit that controls the number of rotations of the screw such that the difference between the thickness and the minimum thickness is equal to or less than a preset threshold value. This aspect makes it possible to reduce sheet thickness variations.

The roll screw extruder has a thickness sensor for measuring the thickness of a sheet-like material extruded from between the pair of upper and lower rolls, and a maximum within a predetermined time measured by the thickness sensor. It is preferable to further include a roll control unit that controls the number of rotations of the roll such that the difference between the thickness and the minimum thickness is equal to or less than a preset threshold value. This aspect makes it possible to reduce sheet thickness variations.

Claims (15)

In a roll screw extruder for extruding a material into a sheet,
A screw for extruding the material,
A casing that accommodates the screw and is provided with an inlet for the material;
And a pair of upper and lower rolls disposed in front of the casing and forming the material extruded by the screw into a sheet.
One of the upper and lower rolls has its axial ends and a body portion between the ends;
A roller screw extruder, wherein the cross section perpendicular to the axial direction in the body portion has an oval shape. In the roller screw extruder according to claim 1,
The screw extruder with a roll, wherein the oval shape is elliptical. In the roller screw extruder according to claim 1,
The other of the upper and lower rolls has its axial ends and a body part between the ends;
The cross section perpendicular to the axial direction in the main body portion of the other roll has an oval shape having the same shape and the same circumferential length as the cross section in the main body portion of the one roll. In the roller screw extruder according to claim 3,
The roll-equipped screw extruder, wherein the upper roll and the lower roll are configured to rotate with a phase difference of 90 ° between the upper roll and the lower roll. In the roller screw extruder according to claim 4,
The oval shape is an ellipse,
Rolled screw extruder, wherein the minor axis length a (mm) of the ellipse and the major axis length b (mm) of the ellipse satisfy the relationship 0.939b-4.14 a a <b . In the roller screw extruder according to claim 5,
The screw extruder with a roll, wherein the length a of the short axis and the length b of the long axis satisfy the relationship of 0.957b-2.95 ≦ a <b. In the roller screw extruder according to claim 1,
The other of the upper and lower rolls has its axial ends and a body part between the ends;
The screw extruder with a roll, wherein a cross section orthogonal to the axial direction in the main body portion of the other roll has a circular shape. In the roller screw extruder according to claim 7,
The screw extruder with a roll, wherein the circumferential length of the main body portion of the upper roll and the circumferential length of the main body portion of the lower roll are different. In the roller screw extruder according to claim 7,
The oval shape is an ellipse,
A screw extruder with a roll, wherein the minor axis length a (mm) of the ellipse and the major axis length b (mm) of the ellipse satisfy the relationship b-0.952 <a <b. In the roller screw extruder according to claim 9,
The screw extruder with a roll, wherein the length a of the short axis and the length b of the long axis satisfy the relationship of b−0.488 ≦ a <b. In the roller screw extruder according to claim 1,
The cross section orthogonal to the axial direction at the both ends of the one roll has a circular shape,
The other of the upper and lower rolls has its axial ends and a body part between the ends;
The cross section orthogonal to the said axial direction in the said both ends of the said other roll has a circular shape, The screw extruder with a roll. The screw extruder with a roll according to any one of claims 1 to 11,
Between the casing and the pair of upper and lower rolls, a material storage portion in which the material extruded by the screw is accumulated is formed.
The screw extruder with a roll is
A pressure sensor that measures the pressure of the material storage section;
And a screw control unit that controls the number of rotations of the screw such that the difference between the maximum pressure and the minimum pressure within the predetermined time measured by the pressure sensor is equal to or less than a preset threshold. Roll screw extruder. The screw extruder with a roll according to any one of claims 1 to 11,
Between the casing and the pair of upper and lower rolls, a material storage portion in which the material extruded by the screw is accumulated is formed.
The screw extruder with a roll is
A pressure sensor that measures the pressure of the material storage section;
A roll control unit that controls the number of rotations of the roll such that the difference between the maximum pressure and the minimum pressure within a predetermined time measured by the pressure sensor is equal to or less than a preset threshold value; Roll screw extruder. The screw extruder with a roll according to any one of claims 1 to 11,
A thickness sensor that measures the thickness of a sheet-like material extruded from between the pair of upper and lower rolls;
And a screw control unit configured to control the number of rotations of the screw such that the difference between the maximum thickness and the minimum thickness within a predetermined time measured by the thickness sensor is equal to or less than a preset threshold value. , Screw extruder with roll. The screw extruder with a roll according to any one of claims 1 to 11,
A thickness sensor that measures the thickness of a sheet-like material extruded from between the pair of upper and lower rolls;
The roll control unit further controls the number of rotations of the roll such that the difference between the maximum thickness and the minimum thickness within a predetermined time measured by the thickness sensor is equal to or less than a preset threshold value. , Screw extruder with roll.

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