Patent Application
20170282418
This application is based upon and claims the benefit of priority from Japanese Patent Applications No. 2016-071980, filed Mar. 31, 2016; No. 2016-176894, filed Sep. 9, 2016; and No. 2016-239573, filed Dec. 9, 2016, the entire contents of all of which are incorporated herein by reference.
Embodiments described herein relate generally to a sheet/film manufacturing (forming) technique for manufacturing (forming) a sheet or a film without causing a gear mark (i.e., horizontal stripes).
In a sheet/film manufacturing (forming) technique, for example, a molten resin is discharged from a T-die in a thin and spread form. The discharged molten resin is fed into a part between two rolls rotating in opposition to each other. The gap between the rolls is controlled. Thus, a sheet or a film appropriate for the intended purpose or use is continuously manufactured (formed). Here, patent literatures 1 to 4 in which apparatuses associated with sheet/film manufacturing (forming) techniques are disclosed are known.
Patent Literature 1: Jpn. Pat. Appln. KOKAI Publication No. 10-249909
Patent Literature 2: Jpn. Pat. Appln. KOKAI Publication No. 8-25458
Patent Literature 3: Jpn. UM Appln. KOKAI Publication No. 62-35815
Patent Literature 4: Jpn. Pat. Appln. KOKAI Publication No. 2005-1170
In the apparatus of Patent Literature 1, each of a reference roll, and driven rolls arranged on both sides of the reference roll is drive-controlled by a precision control motor through a shaft coupling and a reducer. Each of the rolls is stably rotated. Thus, the optical characteristics of the sheet can be improved. In other words, retardation of the sheet becomes small.
In the apparatus of Patent Literature 2, a sheet-like substance is pressed between a first roll and a second roll rotating in opposition to each other and, is thereafter cooled by a third roll. The surface temperatures of the first to third rolls, and the speed of receiving the sheet from the third roll are controlled to within the ranges set in advance. Thus, a polycarbonate sheet in a fine surface condition, without a bend or a curve, and excellent in flatness can be obtained.
In the apparatus of Patent Literature 3, a planetary roller reducer requiring no gears is employed in place of a gear reducer. A plastic sheet is manufactured (formed) without causing a backlash peculiar to a gear mechanism. Thus, a plurality of gear marks (horizontal stripes) are prevented from occurring on the sheet surface in a direction intersecting the feed direction of the sheet.
In the apparatus of Patent Literature 4, a so-called direct-drive drive mechanism is employed as a roll drive system. In such as drive mechanism, the motor (rotor) is directly coupled to the roll (drive shaft part) (i.e., direct coupling) in a state where all the types of reducers including the gear reducer and the planetary roller reducer are excluded. Thus, in a state where the rotation central axis of the roll (drive shaft part) is maintained in a fixed posture, in other words, in a state where the rotation central axis of the motor (rotor) is maintained in a fixed posture, a sheet or a film is manufactured (formed) without causing gear marks (horizontal stripes).
However, in the apparatuses of Patent Literatures 1 and 2, the forming conditions and the operation conditions are limited. That is, the intended purpose or use is limited. For this reason, the apparatuses are deficient in diversity. The apparatus of Patent Literature 3 needs to secure a large installation location for the planetary roller reducer. That is, the planetary roller reducer has a complicated structure. Accordingly, the whole apparatus has to be inevitably made larger. For this reason, reduction in the size of the whole apparatus has a certain limit.
Furthermore, regarding the apparatus of Patent Literature 4, the inventers of the present invention have found the fact that there is the following problem in the process of earnestly carrying out research and development. The apparatus of Patent Literature 4 is specified in such a manner that a roll directly coupled to the motor is rotated.
Incidentally, while the motor is operating, torque ripples occur in the motor. Torque ripples imply a ripple phenomenon caused by the mutual interaction of magnetic flux components between the stator and the rotor when a current is made to flow through the motor to thereby cause relative rotation between the stator and the rotor.
In this case, when an amplitude of a certain frequency component (wavelength component) among frequency components (wavelength components) constituting the torque ripples (pulsation phenomenon) exceeds, for example, a threshold, gear marks (horizontal stripes) of an amplitude corresponding to the amplitude of the frequency component (wavelength component) occur in some cases.
In the specification of the Patent Literature 4, a molten resin discharged from a T-die is fed into a part between two rolls rotating in opposition to each other. At this time, for example, operation conditions or forming conditions such as adjustment of the gap between the rolls, rotation-control of the motor or the like are set. Thus, a sheet or a film is continuously manufactured (formed) without causing gear marks (horizontal stripes).
During such a manufacturing (forming) process, in order to carry out, for example, thickness adjustment of the formed product or disturbance correction, the state (for example, posture, and angle) where one roll is pressed against the other roll is changed. At this time, the influence of the pressed state of the one roll on the other roll, i.e., the changed state of the other roll is directly transmitted to the motor. In other words, the bent states of both the rolls are changed, and the changed bent states are directly transmitted to the motor. Thereby, the posture of the rotation central axis of the motor concerned is changed. When the posture of the rotation central axis of the motor is changed, the amplitude of the torque ripples (pulsation phenomenon) described above is changed correspondingly.
The change in amplitude of the torque ripples (pulsation phenomenon) corresponds to a change in amplitude of each of the various frequency components (wavelength components) occurring in the rotating motor. Here, when an amplitude of a certain frequency component (wavelength component) exceeds, for example, the threshold, in other words, depending on the degree of the magnitude of the pressed state of the one roll, gear marks (horizontal stripes) corresponding to the amplitude (amplitude of the frequency component (wavelength component)) occur in some cases.
At this time, not only gear marks (horizontal stripes) based on a single frequency component (wavelength component), but also gear marks (horizontal stripes) based on a result of duplication of a plurality of frequency components (wavelength components) occur in some cases. Thus, on the surface of the sheet (film), a plurality of gear marks (horizontal stripes) occur in a direction intersecting the feed direction of the sheet (film).
In
Such gear marks (horizontal stripes) constitute a primary factor of deteriorating the external appearance and optical characteristics of the sheet (film). For this reason, a technique capable of maintaining the posture of the rotation central axis of the motor constant even when the state where the one roll is pressed against the other roll is changed, in other words, a technique by which the influence of the pressed state of the one roll on the other roll, i.e., a changed state of the other roll is prevented from being transmitted to motor is required.
Therefore, an object of the present invention is to provide a sheet/film manufacturing (forming) technique capable of previously preventing gear marks (horizontal stripes) from occurring by maintaining the posture of the rotation central axis of the motor constant, and making the influence of the pressed state of one roll on the other roll, i.e., a changed state of the other roll not transmittable to the motor even when the state where the one roll is pressed against the other roll is changed.
As a result of research and development earnestly carried out by the inventors of the present invention with respect to the sheet/film manufacturing (forming) technique in which the motor (rotor) and the roll (drive shaft part) are coupled to each other in a state where all the reducers are excluded, the present invention has been developed as shown in the following items (1) to (6).
(1) In the technical research concerned, a roll structure in which a roll is directly coupled to a motor is employed. That is, a first motor is directly coupled to a first roll. A second motor is directly coupled to a second roll. The first roll and the second roll are rotated in opposition to each other. Operation conditions and forming conditions are set in such a manner that no gear marks (horizontal stripes) occur. In such a state, a molten resin is fed into a part between the first roll and the second roll.
(2) During the manufacture (formation) of a sheet (film), in order to carry out, for example, thickness adjustment of the formed product or disturbance correction, the state (for example, posture, and angle) where the first roll is pressed against the second roll is changed. Then, a plurality of stripes similar to gear marks have occurred. The occurrence timing (period, interval (pitch)) of such stripes (i.e., gear marks (horizontal stripes)) is approximately coincident with the occurrence timing (period, interval (pitch)) of the torque ripples of the second motor. In this case, the influence of the torque ripples of the first motor on the occurrence of the stripes (gear marks (horizontal stripes)) is comparatively small.
(3) The occurrence timing (period, interval (pitch)) of the stripes (gear marks (horizontal stripes) is strongly influenced by torque ripples caused by a cogging phenomenon. The cogging phenomenon implies a pulsation phenomenon caused by variation in the magnetic reluctance between the stator (coils) and the rotor (permanent magnets) when the stator (coils) and the rotor (permanent magnets) are relatively rotated without making a current flow through the motor.
(4) The state (for example, posture, and angle) where the first roll is pressed against the second roll is changed. At this time, the influence of the pressed state of the first roll on the second roll, i.e., the changed state (for example, the changed state of the posture of the rotation central axis of the second roll) of the second roll directly acts on the rotor of the second motor. In other words, the bent states of the first and second rolls change, and the changed bent states are directly transmitted to the second motor (rotor). Then, the posture of the rotation central axis of the rotor changes. Thereby, when the stator and the rotor are relatively rotated, a state where the gap between the stator and the rotor is not maintained constant in the circumferential direction, i.e., a state where the gap is irregularly changed in the circumferential direction is brought about. In such a state, the magnetic reluctance between the stator and the rotor irregularly changes in the circumferential direction. As a result, it becomes impossible to rotate the second motor smoothly at a constant speed.
In that case, amplitudes (i.e., magnitude of the torque ripples) of various frequency components (wavelength components) occurring in the second motor change. At this time, depending on the degree of the magnitude of the torque ripples of a certain frequency component (wavelength component), gear marks (horizontal stripes) corresponding to the amplitude of the frequency component (wavelength component) become liable to occur.
(5) When the coupled state of the second roll and the second motor becomes unstable depending on the degree of the state where the first roll is pressed against the second roll, it cannot necessarily be said that the structure in which the second roll and the second motor are directly coupled to each other is effective. Thus, a technique for maintaining the posture of the rotation central axis of the second motor constant, and making the influence of the pressed state of the first roll on the second roll, i.e., the changed state of the second roll not transmittable to the second motor is required.
(6) In order to realize such a technique, for example, a rotating shaft part, and a power transmission mechanism are prepared. The rotating shaft part is coupled to the second motor (rotor). The power transmission mechanism is arranged between the roll (drive shaft part) and the second motor (rotor). That is, the roll (drive shaft part) is coupled to one end side of the power transmission mechanism. The second motor (rotor) is coupled to the other end side of the power transmission mechanism.
According to this configuration, the influence of the state where the first roll is pressed against the second roll on the second roll, i.e., the changed state of the second roll is never transmitted to the second motor. In this case, the rotating shaft part coupled to the second motor is maintained in a constant posture at all times. The posture of the rotation central axis of the second motor (rotor) is also maintained constant at all times. Thereby, it is possible to smoothly rotate the second motor (rotor) at a constant speed at all times. As a result, it is possible to maintain the torque ripples of the second motor within a range (level) allowing no occurrence of gear marks (horizontal stripes).
Various embodiments will be described hereinafter with reference to the accompanying drawings. In general, according to one embodiment, as shown in
The discharge unit 2 is configured to be able to discharge a molten resin 7a in a thin and spread form. The roll unit 3 is configured to be able to form the discharged molten resin 7a into a form (for example, shape and thickness) suitable for the use by means of a plurality rolls (first roll 12, second roll 13, and third roll 14) to be described later. The temperature regulating unit 4 is configured to be able to regulate the temperatures of the rolls 12, 13, and 14. The push-pull unit 5 is configured to be able to change the state (for example, posture, and angle) where the first and third rolls 12 and 14 are pressed against the second roll 13. The drive unit 6 is configured to be able to control the rotating state of each of the rolls 12, 13, and 14. Hereinafter, specific descriptions will be given.
As shown in
In the cylinder, one or a plurality of screws (not shown) are rotatably inserted. According to a specification in which one screw is inserted in the cylinder, a single-axis extruding unit is configured. According to a specification in which a plurality of (for example, two) screws are inserted in the cylinder, a biaxial extruding unit is configured.
The hopper 11 is configured to be able to put a resin material into the cylinder. For example, a pellet type resin material is put into the hopper 11. The put resin material is melted by the rotating screw and is kneaded in the cylinder. The molten/kneaded resin material is transferred to the tip end of the cylinder in a molten state.
The molten resin transferred to the tip end of the cylinder is fed into the T-die 9 from the connecting pipe 10. The T-die 9 is configured to be able to discharge the transferred molten resin in a spreading manner. The molten resin 7a discharged from the T-die 9 is fed to the roll unit 3. As an example of a method of feeding the molten resin 7a, a specification according to which the molten resin 7a is discharged in the direction of gravity (vertical) from the T-die 9 is shown in the drawing.
As shown in
The first roll 12 has a first rotation central axis 12r. On both sides of the first roll 12, a first drive shaft part 12a and a second drive shaft part 12b are respectively provided. The first and second drive shaft parts 12a and 12b are configured to be concentric with the first rotation central axis 12r. The first drive shaft part 12a is rotatably supported on a first bearing mechanism 15. The second drive shaft part 12b is rotatably supported on a second bearing mechanism 16. Thus, the first roll 12 is supported rotatable around the first rotation central axis 12r.
Furthermore, the first roll 12 has a cylindrical first transcription surface 12s. The first transcription surface 12s is a mirror-finished surface. The first roll 12 (first transcription surface 12s) is configured in such a manner that first roll 12 can be pressed against a second roll 13 (second transcription surface 13s) or can be separated from the second roll 13 (second transcription surface 13s) by the push-pull unit 5.
The second roll 13 has a second rotation central axis 13r. On both sides of the second roll 13, a third drive shaft part 13a and a fourth drive shaft part 13b are respectively provided. The third and fourth drive shaft parts 13a and 13b are configured to be concentric with the second rotation central axis 13r. The third drive shaft part 13a is rotatably supported on a third bearing mechanism 17. The fourth drive shaft part 13b is rotatably supported on a fourth bearing mechanism 18. Thus, the second roll 13 is supported rotatable around the second rotation central axis 13r.
Here, the third and fourth bearing mechanisms 17 and 18 are fixed to a base 30 through fixing parts 29 to be described later. Thereby, the second roll 13 having the third and fourth drive shaft parts 13a and 13b rotatably supported respectively on the third and fourth bearing mechanisms 17 and 18 is maintained in a state where the second roll 13 is fixed to a given position set in advance at all times.
Furthermore, the second roll 13 has a cylindrical second transcription surface 13s. The second transcription surface 13s is a mirror-finished surface. The second transcription surface 13s is configured to be able to guide the molten resin 7a discharged from the T-die in the gravity (vertical) direction in the sheet (film) feed direction Fd set in advance.
The third roll 14 has a third rotation central axis 14r. On both sides of the third roll 14, a fifth drive shaft part 14a and a sixth drive shaft part 14b are respectively provided. The fifth and sixth drive shaft parts 14a and 14b are configured to be concentric with the third rotation central axis 14r. The fifth drive shaft part 14a is rotatably supported on a fifth bearing mechanism 19. The sixth drive shaft part 14b is rotatably supported on a sixth bearing mechanism 20. Thus, the third roll 14 is supported rotatable around the third rotation central axis 14r.
Furthermore, the third roll 14 has a cylindrical feed surface 14s. The feed surface 14s may not necessarily be a mirror-finished surface. The feed surface 14s is configured to be able to guide the molten resin 7b to be described later in the feed direction Fd.
As one example of the layout of the first to third rolls 12, 13, and 14, a specification in which the first to third rolls 12, 13, and 14 are transversely arranged is shown in the drawings. In the transverse arrangement, the first to third rolls 12, 13, and 14 (i.e., first to third rotation central axes 12r, 13r, and 14r) are arranged in the horizontal direction in parallel with each other and at the identical height.
Furthermore, the first to third rolls 12, 13, and 14 may be configured to have diameters identical to each other or may be configured to have diameters different from each other. When the first to third rolls 12, 13, and 14 having diameters different from each other are configured, it is desirable that the diameter of the first roll 12 be set smaller than the diameter of the second roll 13. Thereby, it is possible to improve or maintain constant the responsibility or the followability of the first roll 12.
Here, the responsibility of the first roll 12 implies a speed of response of, for example, a case where the first roll 12 is to be pressed against the second roll 13. The followability of the first roll 12 implies a rotational follow-up speed of the first roll 12, for example, in a state where the first roll 12 is pressed against the second roll 13.
In such a configuration, the molten resin 7a discharged from the discharge unit 2 (T-die 9) in the gravity (vertical) direction in a thin and spread form passes through a part (grounding point) between the first roll 12 and the second roll 13. The molten resin 7a which has passed through the grounding point is cooled while the resin 7a is pushed out along the second transcription surface 13s of the second roll 13, and becomes a molten resin 7b only the surface of which has become solidified. The molten resin 7b passes through a part (grounding point) between the second roll 12 and the third roll 13, and thereafter becomes a sheet (film) 7c in a solidified state the whole of which has flexibility. Thus, the sheet (film) 7c is sent in the direction Fd of arrow. At this time, the sheet (film) 7c has a form (for example, shape, and thickness) corresponding to the use.
Furthermore, the total lengths of the first to third rolls 12, 13, and 14 are set to lengths identical to each other. The total lengths of the rolls 12, 13, and 14 are defined as lengths in a direction (longitudinal direction) parallel to the first to third rotation central axes 12r, 13r, and 14r. In other words, the total lengths of the rolls 12, 13, and 14 are defined as distances between both ends of the rolls 12, 13, and 14. In this case, in the state where the first to third rolls 12, 13, and 14 are transversely arranged, the both ends of the rolls 12, 13, and 14 are linearly lined up in a direction (width direction) perpendicular to the rotation central axes 12r, 13r, and 14r.
Here, in the first to sixth bearing mechanisms 15, 16, 17, 18, 19, and 20 on which the first to sixth drive shaft parts 12a, 12b, 13a, 13b, 14a, and 14b of the first to third rolls 12, 13, and 14 are rotatably supported, the first bearing mechanism 15, the third bearing mechanism 17, and the fifth bearing mechanism 19 are linearly lined up in the direction perpendicular to the first to third rotation central axes 12r, 13r, and 14r. Likewise, the second bearing mechanism, the fourth bearing mechanism, and the sixth bearing mechanism are linearly lined up in the direction perpendicular to the first to third rotation central axes 12r, 13r, and 14r. In short, the positions at which the rolls 12, 13, and 14 are rotatably supported are set at positions identical to each other in the direction (width direction) perpendicular to the first to third rotation central axes 12r, 13r, and 14r.
It should be noted that as the layout of the first to third rolls 12, 13, and 14, longitudinal arrangement or oblique arrangement may be employed in place of the above-mentioned transverse arrangement although not particularly shown. In the longitudinal arrangement, the first to third rolls 12, 13, and 14 (i.e., first to third rotation central axes 12r, 13r, and 14r) are arranged in parallel with each other in the gravity (vertical) direction. Further, in the oblique arrangement, the second roll 13 (second rotation central axis 13r) is arranged at the center, and the first roll 12 (first rotation central axis 12r) and the third roll 14 (third rotation central axis 14r) are arranged on both sides of the second roll 13 in an inclined state.
Furthermore, the first to third rolls 12, 13, and 14 may be arranged in such a manner that the third rotation central axis 14r is not positioned in the same plane as the first and second rotation central axes 12r and 13r. Further, the first to third rolls 12, 13, and 14 may be arranged so that the first and the third rolls 12 and 14 can be moved along the outer circumference of the second roll 13.
Furthermore, in order to compensate for deficiency in cooling of the molten resin, a fourth roll (not shown) may be provided on the downstream side of the third roll 14. Further, regarding the third roll 14, although the roll 14 is made a constituent article of the roll unit 3 of this embodiment, the third roll 14 may be made a constituent article of another unit (not shown) according to the intended purpose or the usage environment.
It should be noted that in
In
In
In
Here, when the first outer cylinder 22 has elasticity, the thickness t3 of the first outer cylinder 22 is set within a range of 1 mm≦t3≦10 mm, and the thickness t4 of the second outer cylinder 24 is set within a range of 10 mm≦t4≦60 mm. The contact pressure (linear pressure) in the touch/contact state is set within the range of 5 kgf/cm to 50 kgf/cm.
Further, when the first cylinder 22 is thin-walled, the thickness t3 of the first outer cylinder 22 is set within a range of 0.1 mm≦t3≦1 mm, and the thickness t4 of the second outer cylinder 24 is set within a range of 10 mm≦t4≦60 mm. The contact pressure (linear pressure) in the touch/contact state is set within a range of 1 kgf/cm to 10 kgf/cm.
As shown in
The temperature regulating unit 4 includes first piping 4a, second piping 4b, and third piping 4c. The first to third piping members 4a, 4b, and 4c are configured in such a manner that a temperature regulating medium is supplied to them from a supply source (not shown). As an example of the temperature regulating medium, liquid (for example, water and oil) and a coolant can be assumed.
The first piping 4a is configured, for example, from the second drive shaft part 12b to the inside of the first roll 12. Inside the first roll 12, the first piping 4a is continuous with a first annular area 12p. The first annular area 12p is configured to be continuous between the first inner cylinder 21 and the first outer cylinder 22 in the circumferential direction. In such a configuration, the temperature regulating medium supplied to the first piping 4a flows from the inside of the first roll 12 through the first annular area 12p, and is thereafter collected again through the first piping 4a. Thereby, the temperature of the first roll 12 (first transcription surface 12s) is adjusted to the temperature set in advance, and is kept at the set temperature.
The second piping 4b is configured, for example, from the fourth drive shaft part 13b to the inside of the second roll 13. Inside the second roll 13, the second piping 4b is continuous with a second annular area 13p. The second annular area 13p is configured to be continuous between the second inner cylinder 23 and the second outer cylinder 24 in the circumferential direction. In such a configuration, the temperature regulating medium supplied to the second piping 4b flows from the inside of the second roll 13 through the second annular area 13p, and is thereafter collected again through the second piping 4b. Thereby, the temperature of the second roll 13 (second transcription surface 13s) is adjusted to the temperature set in advance, and is kept at the set temperature.
The third piping 4c is configured, for example, from the sixth drive shaft part 14b to the inside of the third roll 14. Inside the third roll 14, the third piping 4c is continuous with a third annular area (not shown). The third annular area is configured to be continuous between the third inner cylinder and the third outer cylinder which are not shown in the circumferential direction. In such a configuration, the temperature regulating medium supplied to the third piping 4c flows from the inside of the third roll 14 through the third annular area, and is thereafter collected again through the third piping 4c. Thereby, the temperature of the third roll 14 (feed surface 14s) is adjusted to the temperature set in advance, and is kept at the set temperature.
As shown in
[First and Second Push-Pull Mechanisms 5a and 5b]
The first push-pull mechanism 5a and the second push-pull mechanism 5b are arranged respectively, for example, on both sides of the first roll 12.
The first push-pull mechanism 5a is configured to be able to exert pressing force and traction force on the first bearing mechanism 15. The first bearing mechanism 15 is supported on the supporting plate 25. On the supporting plate 25, a first drive mechanism 53 (drive unit 6) to be described later is mounted. The supporting plate 25 is configured to be able to move along, for example, two linear guides 26 and 27. The two linear guides 26 and 27 are arranged in parallel with each other and in opposition to each other. The linear guides 26 and 27 are configured in a direction perpendicular to the second rotation central axis 13r (see
The second push-pull mechanism 5b is configured to be able to exert pressing force and traction force on the second bearing mechanism 16. The second bearing mechanism 16 is configured to be able to move along, for example, one linear guide 28. The linear guide 28 is configured in a direction perpendicular to the second rotation central axis 13r of the second roll 13.
In this case, the three linear guides 26, 27, and 28 described above are arranged in parallel with each other and in opposition to each other. These three linear guides 26, 27, and 28 are respectively fixed to, for example, three fixing parts 29 on a one-to-one basis. Each of the fixing parts 29 is provided on the base 30. The base 30 is configured in such a manner that the base 30 can be attached to a place 32 set in advance by means of mounting mechanisms 31 (see
In such a configuration, pressing force or traction force is exerted on the first bearing mechanism 15. The acting force at that time is transmitted from the first bearing mechanism 15 to the supporting plate 25. By the acting force, the supporting plate 25 moves along the linear guides 26 and 27. Following the movement of the supporting plate 25, the first bearing mechanism 15 moves together with the first drive mechanism 53 (drive unit 6). On the other hand, pressing force or traction force is exerted on the second bearing mechanism 16. By the acting force at that time, the second bearing mechanism 16 moves along the linear guide 28.
It should be noted that it is desirable that the part (i.e., pressure application part 33) at which the pressing force or the traction force is exerted on the first or second bearing mechanism 15 or 16 by the first or second push-pull mechanisms 5a or 5b be set at, for example, a position intersecting or perpendicularly intersecting the first rotation central axis 12r of the first roll 12, and opposed to a position immediately above the linear guide 26.
For example, in the case of the specification (see
As described above, on the first bearing mechanism 15, the first drive shaft part 12a of the first roll 12 is supported. On the second bearing mechanism 16, the second drive shaft part 12b of the first roll 12 is supported. Accordingly, when the first and second bearing mechanisms 15 and 16 are moved, following the movement, the first and second drive shaft parts 12a and 12b move. At this time, together with the first and second drive shaft parts 12a and 12b, the first roll 12 moves. Thus, it is possible to move the first roll 12 toward or away from the second roll 13.
At this time, the timing with which the pressing force or the traction force is exerted on the first and second bearing mechanisms 15 and 16 is controlled. For example, pressing force is exerted on the first bearing mechanism 15, and traction force is exerted on the second bearing mechanism 16. Traction force is exerted on the first bearing mechanism 15, and pressing force is exerted on the second bearing mechanism 16. Pressing force is exerted on the first bearing mechanism 15 and the second bearing mechanism 16 or traction force is exerted on the first bearing mechanism 15 and the second bearing mechanism 16. Thereby, it is possible to adjust the state (for example, posture and angle) where the first roll 12 is pressed against the second roll 13 with a high degree of accuracy and a high degree of resolution.
[Third and Fourth Push-Pull Mechanisms 5c and 5d]
The third push-pull mechanism 5c and the fourth push-pull mechanism 5d are arranged respectively, for example, on both sides of the third roll 14.
The third push-pull mechanism 5c is configured to be able to exert pressing force and traction force on the fifth bearing mechanism 19. The fifth bearing mechanism 19 is supported on the supporting plate 34. On the supporting plate 34, a third drive mechanism 55 (drive unit 6) to be described later is mounted. The supporting plate 34 is configured to be able to move along, for example, two linear guides 35 and 36. The two linear guides 35 and 36 are arranged in parallel with each other and in opposition to each other. The linear guides 35 and 36 are configured in a direction perpendicular to the second rotation central axis 13r (see
The fourth push-pull mechanism 5d is configured to be able to exert pressing force and traction force on the sixth bearing mechanism 20. The sixth bearing mechanism 20 is configured to be able to move along, for example, one linear guide 37. The linear guide 37 is configured in a direction perpendicular to the second rotation central axis 13r of the second roll 13.
In this case, the three linear guides 35, 36, and 37 described above are arranged in parallel with each other and in opposition to each other. These three linear guides 35, 36, and 37 are respectively fixed to the three fixing parts 29 described above on a one-to-one basis.
In such a configuration, pressing force or traction force is exerted on the fifth bearing mechanism 19. The acting force at that time is transmitted from the fifth bearing mechanism 19 to the supporting plate 34. By the acting force, the supporting plate 34 moves along the linear guides 35 and 36. Following the movement of the supporting plate 34, the fifth bearing mechanism 19 moves together with the third drive mechanism 55 (drive unit 6). On the other hand, pressing force or traction force is exerted on the sixth bearing mechanism 20. By the acting force at that time, the sixth bearing mechanism 20 moves along the linear guide 37.
It should be noted that it is desirable that the part (i.e., pressure application part) at which the pressing force or the traction force is exerted on the fifth or sixth bearing mechanism 19 or 20 by the third or fourth push-pull mechanism 5c or 5d be set at, although not particularly shown, for example, a position intersecting or perpendicularly intersecting the third rotation central axis 14r of the third roll 14, and opposed to a position immediately above the linear guide 35.
For example, in the case of the specification (see
As described above, on the fifth bearing mechanism 19, the fifth drive shaft part 14a of the third roll 14 is supported. On the sixth bearing mechanism 20, the sixth drive shaft part 14b of the third roll 14 is supported. Accordingly, when the fifth and sixth bearing mechanisms 19 and 20 are moved, following the movement, the fifth and sixth drive shaft parts 14a and 14b move. At this time, together with the fifth and sixth drive shaft parts 14a and 14b, the third roll 14 moves. Thus, it is possible to move the third roll 14 toward or away from the second roll 13.
At this time, the timing with which the pressing force or the traction force is exerted on the fifth and sixth bearing mechanisms 19 and 20 is controlled. For example, pressing force is exerted on the fifth bearing mechanism 19, and traction force is exerted on the sixth bearing mechanism 20. Traction force is exerted on the fifth bearing mechanism 19, and pressing force is exerted on the sixth bearing mechanism 20. Pressing force is exerted on the fifth bearing mechanism 19 and the sixth bearing mechanism 20 or traction force is exerted on the fifth bearing mechanism 19 and the sixth bearing mechanism 20. Thereby, it is possible to adjust the state (for example, posture and angle) where the third roll 14 is pressed against the second roll 13 with a high degree of accuracy and a high degree of resolution.
[Apparatus Configuration of First to Fourth Push-Pull Mechanisms 5a, 5b, 5c, and 5d]
Apparatus configurations identical to each other can be applied the aforementioned first to fourth push-pull mechanisms 5a, 5b, 5c, and 5d. In
The push-pull mechanism 5b includes a hydraulic servo type actuator 38, and control unit 39. The actuator 38 is configured to be able to exert pressing force or traction force on the second bearing mechanism 16. The control unit 39 is configured to be able to control the actuator 38. Hereinafter, specific descriptions will be given.
As shown in
The piston rod 44 is configured to extend from the backward chamber 45b along the cylinder main body 40 and the coupling cylinder 41 in a penetrating manner. A base end of the piston rod 44 is connected to the piston 43, and a tip end thereof is connected to the aforementioned pressure application part 33 (see
Here, the forward chamber 45a is pressurized by the control unit 39 and, at the same time, the backward chamber 45b is decompressed. At this time, the piston 43 moves forward. Pressing force is exerted on the pressure application part 33 at the tip end of the piston rod 44. The pressing force is exerted on the second bearing mechanism 16. Thereby, it is possible to move the second bearing mechanism 16 forward along the linear guide 28.
Conversely, the forward chamber 45a is decompressed by the control unit 39 and, at the same time, the backward chamber 45b is pressurized. At this time, the piston 43 moves backward. Traction force is exerted on the pressure application part 33 at the tip end of the piston rod 44. The traction force is exerted on the second bearing mechanism 16. Thereby, it is possible to move the second bearing mechanism 16 backward along the linear guide 28.
Furthermore, the control unit 39 includes a controller 46, servo motor 47, bidirectional pump 48, first measuring instrument 49, second measuring instrument 50, load cell 51, and pressure sensor 52. Here, as an example, a control unit 39 configured to operate the actuator 38 by hydraulic pressure is assumed.
The controller 46 is configured to be able to control the servo motor 47 on the basis of output signals (measurement results) to be described later. The servo motor 47 is configured to be able to selectively control the pressure to be exerted on the forward chamber 45a or the backward chamber 45b by driving the bidirectional pump 48.
In the hydraulic servo system, when the forward chamber 45a is to be pressurized, oil is supplied from the bidirectional pump 48 to the forward chamber 45a, whereby the hydraulic pressure in the forward chamber 45a is raised. Thus, it is possible to exert pressing force on the second bearing mechanism 16 as described above. Conversely, when the backward chamber 45b is to be pressurized, oil is supplied from the bidirectional pump 48 to the backward chamber 45b, whereby the hydraulic pressure in the backward chamber 45b is raised. Thus, it is possible to exert traction force on the second bearing mechanism 16 as described above.
When pressing force or traction force is exerted on the second bearing mechanism 16, the controller 46 controls the bidirectional pump 48 by means of the servo motor 47 on the basis of output signals (measurement results) from the first measuring instrument 49, second measuring instrument 50, load cell 51, and pressure sensor 52. For example, the controller 46 controls the timing for supplying oil to the forward chamber 45a or the backward chamber 45b, an increment in hydraulic pressure, and the like.
Here, the first measuring instrument 49 is configured to be able to measure the position of the piston 43 in the cylinder main body 40 (cylinder 45), and output the measurement result. The second measuring instrument 50 is configured to be able to measure the position of the second bearing mechanism 16, and output the measurement result. The load cell 51 is configured to be able to measure the load exerted on the coupling cylinder 41, and output the measurement result. The pressure sensor 52 is configured to be able to measure the hydraulic pressure in the forward chamber 45a or the backward chamber 45b, and output the measurement result.
Thereby, it is possible to exert pressing force or traction force on the second bearing mechanism 16 with high accuracy. As a result, it is possible to vary the state (for example, posture and angle) where the first roll 12 is pressed against the second roll 23 with a high degree of accuracy.
It should be noticed that as the first to fourth push-pull mechanisms 5a, 5b, 5c, and 5d, in place of the aforementioned hydraulic servo system, although not particularly shown, a system in which the state (for example, posture and angle) where the first or the third roll 12 or 14 is pressed against the second roll 13 is changed by moving a screw or a wedge forward or backward may be employed. Further, the supporting plates 25 and 34 are not necessarily indispensable configurations. It is sufficient if the structure enables the first and third drive mechanisms 53 and 55 (drive unit 6) to be described later to follow the movement of the first and fifth bearing mechanisms 15 and 19.
As shown in
As the first to third motors 56, 57, and 58, multipolar motors using a plurality of permanent magnets are applied. In this case, any types of motors including an inner rotor type motor, and outer rotor type motor are applicable. In the inner rotor type motor, a rotor is rotatably arranged inside a stator. In the outer rotor type motor, a rotor is rotatably arranged outside a stator. Either type of motor can be configured by, for example, arranging a plurality of coils on the stator, and arranging a plurality of permanent magnets on the rotor.
In
Here, it is desirable that the second motor 57 directly contributing to the rotation of the second roll 13 should have a specification which enables generation of high torque at a low rotational speed. In this case, it is desirable, regarding the second motor 57, that the number of poles be set to 8 or more, and the number of slots be set to 15 or more. More desirably, regarding the second motor 57, the number of poles is set to 20 or more, and the number of slots is set to 24 or more. Thereby, on the basis of a particular power-supply specification, as the number of poles becomes larger, the second motor 57 rotates at a lower rotational speed, and generates higher torque.
It should be noted that regarding the first motor 56 and the third motor 58, a first specification which enables generation of low torque at a high rotational speed may be applied, or a second specification which enables generation of high torque at a low rotational speed as in the case of the second motor 57 may also be applied. It should be noted that regarding the first specification, it is necessary to separately provide a speed reducer.
In the sheet/film manufacturing apparatus 1 of this embodiment, the practical rotational speed of the second roll 13 is within the range of 0 rpm to 100 rpm. In such a low rotational speed range, the molten resin 7a (see
In this case, it is desirable that the number of slots be set to 24 or more. It should be noted that as the method of calculating the number of slots, in, for example, WO2011/114574 “permanent magnet motor” (applicant: Mitsubishi Electric Corporation), the following relational expression is shown.
Z/{3(phase)×2P}=2/5(or 2/7)
The number (20) of poles is substituted into the above relational expression. Then, the number of slot is calculated as 24. Thereby, it is possible to generate optimum rotational torque within the range of the practical rotational speed (0 to 100 rpm) of the second roll 13.
Here, in
In the specification of
In this state, rotation centers of the first to third rotating shaft parts 64, 65, and 66, and the rotating parts (rotors 59) coincide with each other on one rotation central axis 67. Thus, the first to third rotating shaft parts 64, 65, and 66 become rotatable together with the rotating parts (rotors 59). Accordingly, it becomes possible to transmit the rotating states (motor output and rotational motion) of the first to third motors 56, 57, and 58 to the outside through the first to third rotating shaft parts 64, 65, and 66.
In the specification of
In
In this state, the rotation centers of the first to third rotating shaft parts 64, 65, and 66, and the rotating parts (rotors 59) coincide with each other on the one rotation central axis 67. Thus, it becomes possible for the first to third rotating shaft parts 64, 65, and 66 to rotate together with the rotating parts (rotors 59).
In the specification of
As shown in
The first rotating shaft part 64 is arranged at the rotating part of the first motor 56. The rotating part is configured to be able to rotate together with the rotor 59 (see
In the first power transmission mechanism 72, an input part is formed on one side thereof in the power transmitting direction, and an output part is formed on the other side thereof in the power transmitting direction. The first power transmission mechanism 72 is arranged between the first motor 56 and the first roll 12. To the one side (input part) of the first power transmission mechanism 72, the first rotating shaft part 64 of the first motor 56 is coupled. To the other side (output part) of the first power transmission mechanism 72, the first drive shaft part 12a of the first roll 12 is coupled.
The first power transmission mechanism 72 is provided with a rigid coupling 73, flexible coupling 74, and reducer 75. On the supporting plate 25, the rigid coupling 73 and the flexible coupling 74 are respectively arranged on both sides of the reducer 75. In the drawings, as one example, the rigid coupling 73 is arranged between the first motor 56 and the reducer 75, and the flexible coupling 74 is arranged between the reducer 75 and the first bearing mechanism 15.
The rigid coupling 73 is provided with a first hub flange 76, and second hub flange 77. The first and second hub flanges 76 and 77 have shapes and sizes identical to each other.
The first hub flange 76 is provided with a disk-like first flange part 78, and cylindrical first attaching part 79. The first flange part 78 is formed integral with one end of the first attaching part 79. The first flange part 78 and the first attaching part 79 are concentrically arranged.
The second hub flange 77 is provided with a disk-like second flange part 80, and cylindrical second attaching part 81. The second flange part 80 is formed integral with one end of the second attaching part 81. The second flange part 80 and the second attaching part 81 are concentrically arranged.
In this case, for example, in a state where both the flange parts 78 and 80 are in contact with each other in opposition to each other, the flange parts 78 and 80 are fixed to each other by means of a plurality of bolts (not shown). Thus, the rigid coupling 73 having the first attaching part 79 and second attaching part 81 which outwardly protrude on both sides is configured. To the first attaching part 79, the first rotating shaft part 64 is coupled. The second attaching part 81 and the reducer 75 are coupled to each other by a coupling shaft 82.
The flexible coupling 74 is provided with a first hub flange 83, second hub flange 84, and leaf spring unit 85. The first and second hub flanges 83 and 84 have shapes and sizes identical to each other.
The first hub flange 83 is provided with a disk-like first flange part 86, and cylindrical first attaching part 87. The first flange part 86 is formed integral with one end of the first attaching part 87. The first flange part 86 and the first attaching part 87 are concentrically arranged.
The second hub flange 84 is provided with a disk-like second flange part 88, and cylindrical second attaching part 89. The second flange part 88 is formed integral with one end of the second attaching part 89. The second flange part 88 and the second attaching part 89 are concentrically arranged.
The leaf spring unit 85 is configured by piling a plurality of leaf springs 90 one on top of another into a laminated form (see
In this case, for example, both the flange parts 86 and 88 are arranged in opposition to each other, and the leaf spring unit 85 is arranged between the flange parts 86 and 88. The flange parts 86 and 88 are fixed to each other together with the leaf spring unit 85 by means of a plurality of bolts 91, washers 92, and nuts 93 (see
It should be noticed that in, for example,
According to such a configuration, the first motor 56 is coupled to the first roll 12 through the first rotating shaft part 64, first power transmission mechanism 72, and first drive shaft part 12a. Here, the first motor 56 is controlled by the controller (not shown). The rotating state (motor output and rotational motion) of the first motor 56 is transmitted to the first drive shaft part 12a through the first rotating shaft part 64 and first power transmission mechanism 72. When the first drive shaft part 12a rotates, the second drive shaft part 12b rotates at the same time. Thus, it becomes possible to control the rotating state (for example, number of revolutions, and rotational speed) of the first roll 12. In this case, the rotating state (motor output and rotational motion) of the first motor 56 is transmitted to the first roll 12 in a state where the rotational speed is reduced and the torque is increased by the first power transmission mechanism 72 (reducer 75).
As shown in
The second rotating shaft part 65 is arranged at the rotating part of the second motor 57. The rotating part is configured to be able to rotate together with the rotor 59 (see
In the second power transmission mechanism 95, an input part is formed on one side thereof in the power transmitting direction, and an output part is formed on the other side thereof in the power transmitting direction. The second power transmission mechanism 95 is arranged between the second motor 57 and the second roll 13. To the one side (input part) of the second power transmission mechanism 95, the second rotating shaft part 65 of the second motor 57 is coupled. To the other side (output part) of the second power transmission mechanism 95, the third drive shaft part 13a of the second roll 13 is coupled.
The second power transmission mechanism 95 is provided with a flexible coupling 74. The flexible coupling 74 is arranged between the second motor 57 and the third bearing mechanism 17. The flexible coupling 74 is provided with a first hub flange 83, second hub flange 84, and leaf spring unit 85. The first and second hub flanges 83 and 84 have shapes and sizes identical to each other.
In the flexible coupling 74 of the second power transmission mechanism 95, the first attaching part 87 and the second attaching part 89 are elongated according to the distance between the second motor 57 and the third bearing mechanism 17. To the first attaching part 87, the second rotating shaft part 65 is coupled. To the second attaching part 89, the third drive shaft part 13a supported on the third bearing mechanism 17 is coupled. Configurations other than the above are identical to the flexible coupling 74 of the first power transmission mechanism 72. Accordingly, the configurations identical to the flexible coupling 74 of the first power transmission mechanism 72 are denoted by reference symbols identical to those of the mechanism 72, and descriptions of them are omitted.
According to such a configuration, the second motor 57 is coupled to the second roll 13 through the second rotating shaft part 65, second power transmission mechanism 95, and third drive shaft part 13a. Here, the second motor 57 is controlled by the controller (not shown). The rotating state (motor output and rotational motion) of the second motor 57 is transmitted to the third drive shaft part 13a through the second rotating shaft part 65, and second power transmission mechanism 95. The third drive shaft part 13a rotates, and the fourth drive shaft part 13b rotates at the same time. Thus, it becomes possible to control the rotating state (for example, number of revolutions, and rotational speed) of the second roll 13.
In this case, the rotating state (motor output and rotational motion) of the second motor 57 is transmitted to the second roll 13 as it is by the second power transmission mechanism 95 without the rotating state (motor output and rotational motion) being changed (for example, without the rotational speed being reduced). As a result, it is possible to rotate the second roll 13 with the timing identical to the rotating state (motor output and rotational motion) of the second motor 57. It should be noted that, in this description, the identical timing implies high-level concepts such as identical number of revolutions, identical rotational speed, identical angular speed, identical angular acceleration, and the like.
As shown in
The third rotating shaft part 66 is arranged at the rotating part of the third motor 58. The rotating part is configured to be able to rotate together with the rotor 59 (see
In the third power transmission mechanism 96, an input part is formed on one side thereof in the power transmitting direction, and an output part is formed on the other side thereof in the power transmitting direction. The third power transmission mechanism 96 is arranged between the third motor 58 and the third roll 14. To the one side (input part) of the third power transmission mechanism 96, the third rotating shaft part 66 of the third motor 58 is coupled. To the other side (output part) of the third power transmission mechanism 96, the fifth drive shaft part 14a of the third roll 14 is coupled.
The third power transmission mechanism 96 is provided with a rigid coupling 73, flexible coupling 74, and reducer 75. In this case, the arrangement configuration of the third power transmission mechanism 96 is identical to the aforementioned first power transmission mechanism 72. Accordingly, configurations identical to the first power transmission mechanism 72 are denoted by reference symbols identical to the first power transmission mechanism 72, and descriptions of them are omitted.
In such a configuration, the third motor 58 is coupled to the third roll 14 through the third rotating shaft part 66, third power transmission mechanism 96, and fifth drive shaft part 14a. Here, the third motor 58 is controlled by the controller (not shown). The rotating state (motor output and rotational motion) of the third motor 58 is transmitted to the fifth drive shaft part 14a through the third rotating shaft part 66, and third power transmission mechanism 96. The fifth drive shaft part 14a rotates, and the sixth drive shaft part 14b rotates at the same time. Thus, it becomes possible to control the rotating state (for example, number of revolutions, and rotational speed) of the third roll 14. In this case, the rotating state (motor output and rotational motion) of the third motor 58 is transmitted to the third roll in a state where the rotational speed is reduced and the torque is increased by the third power transmission mechanism 96 (reducer 75).
According to this embodiment, the second power transmission mechanism 95 provided with the flexible coupling 74 is arranged between the second motor 57 and the second roll 13. That is, the second motor 57 and the second roll 13 are coupled to each other through the second power transmission mechanism 95 provided with the flexible coupling 74. Thereby, when the state where the first roll 12 is pressed against the second roll 13 is changed, the whole of the changed state occurring in the second roll 13 is completely absorbed and removed by the flexible coupling 74.
Here, as the changed state occurring in the second roll 13, the changed state of the rotating shaft of the second roll 13 occurring when the first roll 12 is moved toward or away from the second roll 13, for example, an “angular deviation” such as an eccentricity or a deflection angle of the second rotation central axis 13r is assumed. Even when such an angular deviation (eccentricity/deflection angle) has occurred, the flexible coupling 74 (leaf spring unit 85) is elastically deformed according to the degree of the magnitude of the angular deviation (eccentricity/deflection angle). Thereby, the whole of the angular deviation (eccentricity/deflection angle) is completely absorbed and removed. Accordingly, the influence of the state where the first roll 12 is pressed against the second roll 13 on the second roll, i.e., the changed state of the second roll 13 is never transmitted to the second motor 57 (second rotating shaft part 65).
Furthermore, the flexible coupling 74 (leaf spring unit 85) is elastically deformed, whereby the posture of the second motor 57 (rotor 59) or the second rotating shaft part 65, i.e., the posture of the rotation central axis 67 is maintained constant at all times. At the same time, the rotating state (motor output and rotational motion) of the second motor 57 is transmitted to the second roll 13 as it is by the second power transmission mechanism 95 without the rotating state (motor output and rotational motion) being changed (for example, without the rotational speed being reduced). As a result, it is possible to rotate the second roll 13 with the timing identical to the rotating state (motor output and rotational motion) of the second motor 57.
At this time, the torque ripples (pulsation phenomenon) of the second motor 57 are maintained at a level at which gear marks (horizontal stripes) do not occur. As a result, it is possible to previously prevent gear marks (horizontal stripes) from occurring. Thus, it is possible to manufacture (form) a sheet (film) without causing gear marks (horizontal stripes).
Furthermore, according to this embodiment, when viewed from a direction (longitudinal direction) parallel to the first to third rotation central axes 12r, 13r, and 14r, the temperature regulating unit 4 is arranged on one side of the roll unit 3 (first to third rolls 12, 13, and 14), and the drive unit 6 is arranged on the other side of the roll unit 3. Thereby, it is possible to improve the maintainability of both the units 4 and 6. Furthermore, in carrying out maintenance of the piping 4a, 4b, and 4c of the temperature regulating unit 4, for example, even when a liquid or a coolant leaks or drops, the electric circuit or the like of the drive unit 6 is never adversely affected.
Furthermore, according to this embodiment, regarding the second motor 57 directly contributing to the rotation of the second roll 13, the number of poles is set to 8 or more, and the number of slots is set to 15 or more, and more desirably, the number of poles is set to 20 or more, and the number of slots is set to 24 or more. Thereby, it is possible to generate optimum rotational torque within the range of the practical rotational speed (0 to 100 rpm) of the second roll 13. That is, it is possible to realize a second motor 57 capable of generating high torque at a low rotational speed. As a result, it is possible to previously prevent such a situation that formation of a sheet (film) 7c cannot be carried out due to an overload on the second motor 57 from occurring.
In
As is evident from the test results, although in the conventional sample (see
Furthermore, in such an occurrence test, a range of wavelengths T (mm) satisfying the relational expression (M≧π×D/T) to be described later is set. In the setting method, as shown in
At this time, the pushing period on which the first roll 12 is made to carry out a reciprocating motion is made H, and the speed (circumferential speed) of the molten resin passing through the part between the first roll 12 and the second roll 13 is made S. Then, in the molten resin, a periodic change appears in the flow direction of the molten resin with timing (wavelength, pitch) of P=S×H. That is, a thickness variation occurs in the molten resin with timing (wavelength, pitch) of P=S×H.
In
When the rotational torque is high (ΔTmax), the pressing amount or the feed amount of the molten resin per unit rotational angle Δθ becomes larger (ΔVmax). Thereby the thickness of the molten resin increases. The reaction force of the molten resin against the first roll 12 becomes larger. As a result, as is evident from the locus (O3, O7, O11, and O15) of the rotation center, the first roll 12 slightly retreats (displacement or deformation).
When the rotational torque is low (ΔTmin), the pressing amount or the feed amount of the molten resin per unit rotational angle Δθ becomes smaller (ΔVmin). Thereby the thickness of the molten resin decreases.
The reaction force of the molten resin against the first roll 12 becomes smaller. As a result, as is evident from the locus (O1, O5, O9, and O13) of the rotation center, the first roll 12 slightly advances (displacement or deformation).
The inventors of the present invention has earnestly carried out research on the timing (wavelength, pitch) (i.e., P=S×H) of the thickness variation of the molten resin. Here, for example, while the first roll 12 makes one rotation, a thickness variation was made to occur in the flow direction of the molten resin with timing (wavelength, pitch) of P (=S×H)≦5 mm. At this time, the width of the thickness variation is 0.3 μm or less. Such a thickness variation is absorbed and removed by the viscoelastic characteristics of the molten resin. As a result, it has been confirmed that it is possible to manufacture (form) a sheet (film) without causing gear marks (horizontal stripes).
Furthermore, as a result of earnest research carried out by the inventors of the present invention, it has been confirmed that when a thickness variation is made to occur with timing (wavelength, pitch) of P (=S×H)≦3 mm, gear marks (horizontal stripes) are prevented from occurring more effectively.
Such a thickness variation coincides with the occurrence timing of the short-period oscillation resulting from a cogging phenomenon of the second motor 57. Further, such a short-period oscillation occurs with the identical timing along the outer circumferential surface of the second roll rotating with the timing identical to the second motor. Then, the range of the wavelengths T (mm) to be described later can be specified as the oscillation occurrence timing satisfying the relationship of P≦5 mm (desirably 3 mm), i.e., as a distance between two points identical to each other in phase.
It should be noticed that when the range of the wavelengths T (mm) to be described later is P>5 mm, a “thickness variation” which is not absorbed by the viscoelastic characteristics of the molten resin occurs. For example, when P=13 mm, the width of the thickness variation becomes 10 μm. In this case, occurrence of gear marks (horizontal stripes) cannot be prevented and, as a result, gear marks remain on the manufactured (formed) sheet (film).
After the startup of the sheet/film manufacturing apparatus, and at the previous step before manufacturing (forming) of a completed product, there is sometimes a case where gear marks (horizontal stripes) occur on the surface of the sheet (film) 7c (see
In this case, according to the earnest technical research carried out by the inventors of the present invention, when a variation has been given to the molten resin fed along the roll unit 3 with a specific period, it has been made clear that regarding the pitch of the thickness variation occurring on the sheet (film), in other words, a short-period oscillation having a wavelength of 5 mm or less on the sheet (film), the variation is absorbed by the viscoelastic characteristics of the molten resin, and the influence of the variation of the molten resin does not appear.
Thereby, it can be seen that when the number of times of short-period oscillations occurring while the roll makes one rotation is equal to or greater than a value obtained by dividing the outer circumferential length by the wavelength 5 mm, the short-period oscillations have no influence on the molten resin.
The cogging phenomena occur the number of times corresponding to the least common multiple of the number of poles and the number of slots while the motor (rotor) makes one rotation.
Thus, letting the least common multiple of the number of poles and the number of slots of the second motor 57 be M, the diameter of the second roll 13 be D (mm), and the aforementioned wavelength be T (mm), the following relational expression is established.
M=π×D/T(π: circular constant)
As described above, it has turned out that with respect to the short-period oscillations having a wavelength of 5 mm or less (T≦5) on the sheet (film), the variation is absorbed by the viscoelastic characteristics of the molten resin, and no influence of the variation of the molten resin appears. Thus the least common multiple M of the number of poles and the number of slots of the second motor 57 is configured to satisfy the following relational expression.
M≧π×D/T(T=5)
That is, M≧π×D/5
Thereby, torque ripples (pulsation phenomenon) based on the cogging phenomena are absorbed by the viscoelastic characteristics of the molten resin. As a result, it is possible to manufacture (form) a sheet (film) without causing gear marks (horizontal stripes).
In the second motor 57 of the drive unit 6 (second drive mechanism 54), in order to make the second motor 57 generate high torque at a low rotational speed, the number of poles is increased. With the increase in the number of poles, the external dimensions of the second motor become larger. At this time, depending on the degree of the increase in the number of poles, the external dimensions of the second motor 57 becomes larger than the diameter of the second roll 13 in some cases. Then, it becomes difficult to arrange the second motor 57 between the first motor 56 and the third motor 58.
More specifically, for example, when the first roll 12 is pressed against the second roll 13 in order to carry out thickness adjustment of the formed product or disturbance correction, the first motor 56 is moved toward the second motor 57 following the first roll 12. At this time, depending on the degree of the diameter of the second roll 13 or on the degree of the external dimensions of the second motor 57, the first motor 56 comes into contact with the second motor 57. Then, it becomes impossible to carry out thickness adjustment of the formed product or disturbance correction. As a result, it becomes impossible to maintain the quality of the sheet (film) as the completed product constant.
As the measure to solve such a problem, for example, it is advisable to arrange the second motor 57 at a position separate from the first motor 56. As an example of such an arrangement method, a first method of making the space between the first motor 56 and the first roll 12 smaller than the space between the second motor 57 and the second roll 13, or a second method of making the space between the second motor 57 and the second roll 13 larger than the space between the first motor 56 and the first roll 12 can be assumed.
Further, as described above, the first bearing mechanism 15, the third bearing mechanism 17, and the fifth bearing mechanism 19 are linearly lined up in a direction perpendicular to the first to third rotation central axes 12r, 13r, and 14r. Thus, on the basis of the bearing mechanisms 15, 17, and 19, the aforementioned arrangement method is considered.
For example, it is possible to assume a first method of making the space between the first motor 56 and the first bearing mechanism 15 smaller than the space between the second motor 57 and the third bearing mechanism 17, or a second method of making the space between the second motor 57 and the third bearing mechanism 17 larger than the space between the first motor 56 and the first bearing mechanism 15.
In
Here, between the second motor 57 and the second roll 13 (third bearing mechanism 17), the second power transmission mechanism 95 is arranged. The second power transmission mechanism 95 is provided with two flexible couplings 74, and spacer 94 (intermediate shaft part). The total length of the spacer 94 is set according to the distance between the second motor 57 and the second roll 13 (third bearing mechanism 17). For example, by adjusting length of the intermediate part 94p of the spacer 94 to be described later, it is possible to arrange the second power transmission mechanism 95 between the second motor 57 and the second roll 13 (third bearing mechanism 17) with high accuracy.
As shown in
Furthermore, the first flange part 97 and the second flange part 98 have shapes and sizes identical to each other. In this case, the first and second flange parts 97 and 98 of the spacer 94, and the first and second flange parts 86 and 88 of the first and second flexible couplings 74 have shapes and sizes identical to each other.
The two flexible couplings 74 are respectively provided on both sides of the spacer 94. Between the spacer 94 (first flange part 97) and the second motor (first rotating shaft part 65), the first flexible coupling 74 (one of the two flexible couplings 74) is arranged. Between the spacer 94 (second flange part 98) and the second roll 13 (third drive shaft part 13a), the second flexible coupling 74 (the other of the two flexible couplings 74) is arranged.
The first flexible coupling 74 (one of the two flexible couplings 74) is configured by being provided with the aforementioned leaf spring unit 85 between the aforementioned first hub flange 83 and the aforementioned spacer 94 (first flange part 97). In this case, the leaf spring unit 85 is arranged between the first flange part 86 of the first hub flange 83 and the first flange part 97 of the spacer 94. The flange parts 86 and 97 are fixed to each other by means of a plurality of bolts 91 and the like. Thus, one of the flexible couplings 74 can be configured.
The second flexible coupling (the other of the two flexible couplings 74) is configured by being provided with the aforementioned leaf spring unit 85 between the aforementioned second hub flange 84 and the aforementioned spacer 94 (second flange part 98). In this case, the leaf spring unit 85 is arranged between the second flange part 88 of the second hub flange 84 and the second flange part 98 of the spacer 94. The flange parts 88 and 98 are fixed to each other by means of a plurality of bolts 91 and the like. Thus, the second flexible coupling 74 (the other of the two flexible couplings 74) can be configured.
Here, in
More specifically, a plurality of shaft members (intermediate parts 94p) are prepared, and these shaft members (intermediate parts 94p) are flexibly coupled to each other by the first flexible coupling 74. Thus, it is possible to configure one intermediate shaft part (spacer) 94 in which a plurality of shaft members (intermediate parts 94p) are coupled to each other.
According to such a configuration, the changed state of the rotating shaft of the second roll 13 occurring when the first roll 12 is moved toward or away from the second roll 13, for example, an “angular deviation” such as an eccentricity or a deflection angle of the second rotation central axis 13r is absorbed and removed by the intermediate shaft part (spacer) 94 or the intermediate part 94p being inclined with the one shaft coupling (shaft coupling 74 closer to the second motor 57) used as a base point. Thereby, the posture of the rotating shaft (rotation center) of the second motor 57 is maintained constant at all times.
It should be noted that in
As the space between the first motor 56 and the first roll 12 (first bearing mechanism 15) becomes longer, not only the torsional rigidity is made lower, but also the weight (mass) is made heavier correspondingly to the elongated amount of space. Then, as described previously, there is a possibility of the responsibility or the followability of the first roll 12 being lowered.
However, as described in this embodiment, the space between the first motor 56 and the first roll 12 (first bearing mechanism 15) is set smaller than the space between the second motor 57 and the second roll 13 (third bearing mechanism 17). Then, it is possible to maintain or improve the torsional rigidity, and reduce the weight (mass) correspondingly to the shortened amount of space.
Thereby, it is possible to improve the responsibility or the followability of the first roll 12 or maintain the responsibility or the followability thereof constant. As a result, it is possible to maintain the quality of the sheet (film) as the completed product constant. It should be noted that other advantages are identical to the advantages of the aforementioned first embodiment, and hence descriptions of them are omitted.
This embodiment is an improvement of the aforementioned second embodiment (
As shown in
The coupling parts 111, and 112 on both sides of the first power transmission mechanism 72 are respectively attached to the first rotating shaft part 64 of the first motor 56 and the first drive shaft part 12a of the first roll 12. That is, the first disk 100 is coupled to the first rotating shaft part 64 through the coupling part 111. Furthermore, the second disk 101 is coupled to the first drive shaft part 12a through the coupling part 112.
The coupling parts 111, and 112 on both sides of the third power transmission mechanism 96 are respectively attached to the third rotating shaft part 66 of the third motor 58 and the fifth drive shaft part 14a of the third roll 14. That is, the first disk 100 is coupled to the third rotating shaft part 66 through the coupling part 111. Furthermore, the second disk 101 is coupled to the fifth drive shaft part 14a through the coupling part 112.
The first disk 100, second disk 101, and intermediate disk 102 have shapes and sizes identical to each other. The first disk 100, the second disk 101, and the intermediate disk 102 have a hollow disk-like shape. The first disk 100, the second disk 101, and the intermediate disk 102 are arranged in parallel with each other and in opposition to each other. The intermediate disk 102 is arranged between the first disk 100 and the second disk 101.
On both sides of the intermediate disk 102, first and second intermediate surfaces 102a and 102b opposed to each other in parallel with each other are configured. The first disk 100 is arranged in opposition to the first intermediate surface 102a of the intermediate disk 102. The first disk 100 has a first surface 100a opposed to the first intermediate surface 102a in parallel with each other.
A link mechanism is configured between the first surface 100a and the first intermediate surface 102a. That is, on the first surface 100a, two first pins 107 are provided. The two first pins 107 protrude toward the first intermediate surface 102a in parallel with each other. On the first intermediate surface 102a, two second pins 108 are provided. The two second pins 108 protrude toward the first surface 100a in parallel with each other.
The first pins 107 and the second pins 108 are coupled to each other through first and second links 103 and 104. In each of the first and second links 103 and 104, two coupling holes 113 and 114 are formed. In the coupling holes 113 and 114, bearings (not shown) are accommodated. In each of the first and second links 103 and 104, the first pin 107 is rotatably coupled to the one coupling hole 113. The second pin 108 is rotatably coupled to the other coupling hole 114.
On the other hand, the second disk 101 is arranged in opposition to the second intermediate surface 102b of the intermediate disk 102. The second disk 101 has a second surface 101a opposed to the second intermediate surface 102b in parallel with each other.
A link mechanism is configured between the second surface 101a and the second intermediate surface 102b. That is, on the second intermediate surface 102b, two third pins 109 are provided. The two third pins 109 protrude toward the second surface 101a in parallel with each other. On the second surface 101a, two fourth pins 110 are provided. The two fourth pins 110 protrude toward the second intermediate surface 102b in parallel with each other.
The third pins 109 and the fourth pins 110 are coupled to each other through the third and fourth links 105 and 106. In each of the third and fourth links, two coupling holes 115 and 116 are formed. In the coupling holes 115 and 116, bearings (not shown) are accommodated. In each of the third and fourth links 105 and 106, the third pin 109 is rotatably coupled to the one coupling hole 115. The fourth pin 110 is rotatably coupled to the other coupling hole 116.
It should be noted that when the aforementioned coupling 99 is applied to the second power transmission mechanism 95, the first disk 100 is coupled to the second rotating shaft part 65 through a coupling part 111, and the second disk 101 is coupled to the third drive shaft part 13a through a coupling part 112. It is needless to say that, thereby, advantages identical to the first embodiment can be obtained.
According to this embodiment, the rotating states (motor output and rotational motion) of the first and third motors 56 and 58 are transmitted from the first and third rotating shaft parts 64 and 66 to the first disks 100 through the coupling parts 111. At this time, the rotational motion of the first disks 100 is transmitted from the first and second links 103 and 104 to the intermediate disks 102, and is thereafter transmitted from the third and fourth links 105 and 106 to the second disks 101. At this time, the rotational motion of the second disks 101 is transmitted from the coupling parts 112 to the first and third rolls 12 and 14 through the first and fifth drive shaft parts 12a and 14a. Thus, it is possible to rotate the first and third rolls 12 and 14 with the timing identical to the rotating states (motor output and rotational motion) of the first and third motors 56 and 58.
Furthermore, the changed state of the second roll 13 occurring when the first roll 12 is moved toward or away from the second roll 13 is absorbed and removed by the aforementioned link mechanisms. Thereby, it is possible to maintain the postures of the first and third rotating shaft parts 64 and 66 constant at all times. It should be noted that other configurations are identical to the second embodiment, and hence configurations identical to the second embodiment are denoted by reference symbols identical to the second embodiment, and descriptions of them are omitted. Furthermore, the advantages other than the above are identical to the aforementioned first and second embodiments, and hence descriptions of them are omitted.
This embodiment is an improvement of the aforementioned second embodiment (
According to this embodiment, the metallic balls rotate and turn along the sockets (sliding surfaces), whereby it is possible to rotate the first and third rolls 12 and 14 with the timing identical to the rotating states (motor output and rotational motion) of the first and third motors 56 and 58. It should be noted that other configurations are identical to the second embodiment, and hence configurations identical to the second embodiment are denoted by reference symbols identical to the second embodiment, and descriptions of them are omitted. Furthermore, the advantages of this embodiment are identical to the aforementioned first and second embodiments, and hence descriptions of them are omitted.
It should be noted that, here, as an example, although a specification in which ball joints 117 are applied as the shaft couplings of the first and third power transmission mechanisms 72 and 96 has been described, the specification is not limited to the above, and such a ball joint 117 may be applied as the shaft coupling of the aforementioned second power transmission mechanism 95. For example, in the aforementioned embodiment associated with
In
In this case, the elastic shaft coupling 120 is rotatably supported on the stays 121 through the bearings 122. The stays 121 are made to stand on a seat 123. The seat 123 is fixed to a base 30. Thus, the elastic shaft coupling 120 is rotatably fixed to the seat 123 (base 30) through the stays 121. In the drawing, as an example, the elastic shaft coupling 120 is rotatably supported on the two stays 121.
To one side (the other end of an inner shaft member 124 to be described later) of the elastic shaft coupling 120, the second rotating shaft part 65 of the second motor 57 is coupled. To the other side (the other end of an outer shaft member 125 to be described later) of the elastic shaft coupling 120, the third drive shaft part 13a of the second roll 13 is coupled.
As an example of a coupling method, in the drawing, the second rotating shaft part 65 is coupled to the elastic shaft coupling 120 by press fitting the second rotating shaft part 65 into a fitting part 124e on one side (the other end of the inner shaft member 124) of the elastic shaft coupling 120. Such a coupling method is, although not particularly shown, also applicable to the other side (the other end of the outer shaft member 125) of the elastic shaft coupling 120, the other side being the part to which the third drive shaft part 13a is to be coupled.
The elastic shaft coupling 120 is provided with an inner shaft member 124, outer shaft member 125, and elastic body 126. As the elastic body 126, for example, rubber, synthetic resin, and the like are applicable. The elastic body 126 is configured to be able to lie (to be interposed) between a convex part 124p and the concave part 125p without any clearance left.
The inner shaft member 124 is configured to have both ends, and to be concentric with the central axis 124r. The two stays 121 described above are respectively arranged on both end sides of the inner shaft member 124. The inner shaft member 124 is supported on the stays 121 at both end sides thereof.
At one end of the inner shaft member 124, a convex part 124p is provided. The convex part 124p is configured to concentrically protrude from the one end of the inner shaft member 124 along the central axis 124r. In the drawing, as an example, although a rectangular convex part 124p is shown, various shapes other than this such as triangular, polygonal, and the like are applicable.
At the other end of the inner shaft member 124, the aforementioned fitting part 124e is configured. The fitting part 124e is configured by making the other end of the inner shaft member 124 concentrically and partly depressed along the central axis 124r. The shape of the fitting part 124e is set correspondingly to the shape of the second rotating shaft part 65.
The outer shaft member 125 is configured to have both ends, and to be concentrically circular with respect to the central axis 125r. At one end of the outer shaft member 125, a concave part 125p is provided. The concave part 125p is configured by making the one end of the outer shaft member 125 concentrically and partly depressed along the central axis 125r. In the drawing, as an example, although a rectangular concave part 125p is shown, various shapes other than this such as triangular, polygonal, and the like are applicable.
At the other end of the outer shaft member 125, a fitting part (not shown) having, for example, a configuration identical to the aforementioned fitting part 124e is provided. The third drive shaft part 13a is press fitted into such a fitting part, whereby the third drive shaft part 13a can be coupled to the other end (the other side of the elastic shaft coupling 120) of the outer shaft member 125.
In the elastic shaft coupling 120 described above, the convex part 124p of the inner shaft member 124 to which the second rotating shaft part 65 is coupled is inserted into the convex part 125p of the outer shaft member 125 to which the third drive shaft part 13a is coupled. Between the convex part 124p and the concave part 125p, the elastic body 126 is interposed. Regarding such an interposing method, although not particularly shown, for example, the elastic body 126 is previously attached to the whole outer surface of the convex part 124p. Subsequently, the convex part 124p is forcibly inserted into the concave part 125p together with the elastic body 126, whereby the elastic body 126 can be interposed between the convex part 124p and the concave part 125p without any clearance left.
In such a state, the rotation centers of the second rotating shaft part 65 and the rotating part (rotor 59), and the central axes 124r and 125r coincide with each other on the one rotation central axis 67. The second rotating shaft part 65, and the elastic shaft coupling 120 (inner shaft member 124 and outer shaft member 125) become rotatable together with the rotating part (rotor 59).
According to this embodiment, the both end sides of the inner shaft member 124 are supported on the stays 121. For this reason, for example, when the state where the first roll 12 (see
At this time, the whole of the changed state (for example, angular deviation (eccentricity, deflection angle) occurring in the second roll 13 is completely absorbed and removed by the elastic shaft coupling 120 (elastic body 126) being elastically deformed. Accordingly, the changed state of the second roll 13 is never transmitted to the second motor 57 (second rotating shaft part 65). At the same time, the posture of the second motor 57 (rotor 59) or the second rotating shaft part 65, i.e., the posture of the rotation central axis 67 is maintained constant at all times.
Thus, the rotating state of the second motor 57 is not changed, and is transmitted to the second roll 13 as it is, whereby the second power transmission mechanism 95 which makes the second roll 13 rotate with the timing identical to the rotating state of the second motor 57 is realized. It should be noted that other advantages are identical to the first embodiment, and hence descriptions of them are omitted.
In
The one pressing mechanism 127a is arranged between the elastic shaft coupling 120 (more specifically, the other end of the outer shaft member 125) and the third bearing mechanism 17. The other pressing mechanism 127b is arranged between the aforementioned second piping 4b and the fourth bearing mechanism 18. Each of both the pressing mechanisms 127a and 127b is provided with a flexible shaft 128, bearing housing 129, linear guide 130, piston rod 131, and actuator 132.
In the one pressing mechanism 127a, the flexible shaft 128 is provided between the third drive shaft part 13a and the other end (the other side of the elastic shaft coupling 120) of the outer shaft member 125. The flexible shaft 128 is configured to be continuous from the third drive shaft part 13a, and extend along the rotation central axis 67 concentrically therewith. In the drawing, as an example, the flexible shaft 128 is configured from the third drive shaft part 13a to the position immediately before the other end of the outer shaft member 125.
In the other pressing mechanism 127b, the flexible shaft 128 is provided between the fourth drive shaft part 13b and the second piping 4b. The flexible shaft 128 is configured to be continuous from the fourth drive shaft part 13b, and extend along the second rotation central axis 13r concentrically therewith.
In both the pressing mechanisms 127a and 127b, the whole of the flexible shaft 128 is made liable to be elastically deformed. As a method of realizing such an effect, a method of making the diameter of the flexible shaft 128 smaller than the third drive shaft part 13a (fourth drive shaft part 13b) can be employed.
The bearing housing 129 rotatably supports the flexible shaft 128 thereon. The bearing housing 129 is configured to be able to move along the linear guide 130. The linear guide 130 is arranged in a direction intersecting (perpendicular to) the flexible shaft 128 (rotation central axis 67).
The piston rod 131 has both ends (base end and tip end). The base end of the piston rod 131 is coupled to the actuator 132. The tip end of the piston rod 131 is coupled to the bearing housing 129. The actuator 132 is configured to be able to make the piston rod 131 carry out a reciprocating motion. In such a configuration, the piston rod 131 is made to carry out a reciprocating motion (protrusion, retraction). Thereby, it is possible to advance or retreat the bearing housing 129 along the linear guide 130.
In this case, it is possible to exert pressing force and traction force on the flexible shaft 128 by making the piston rod 131 protrude or retract (making the bearing housing advance or retreat). The pressing force is changeable so that the pressing force can be increased or decreased according to the distance (protrusion amount of the piston rod 131) for which the bearing housing 129 is made to advance. The traction force is changeable so that the traction force can be increased or decreased according to the distance (retraction amount of the piston rod 131) for which the bearing housing 129 is made to retreat.
In such a configuration, it is possible to elastically deform the flexible shaft 128 according to the pressing force and the traction force. By making the pressing force and the traction force larger, the deformation amount (degree of deformation) of the flexible shaft 128 can be made larger. In this case, the magnitude of each of the pressing force and the traction force is set to such a degree that bending of the flexible shaft 128 caused by the changed state (for example, angular deviation (eccentricity, deflection angle) of the second rotation central axis 13r) occurring in the second roll 13 is eliminated by the pressing force and the traction force.
[Operations of Pressing Mechanisms 127a and 127b]
For example, as shown in
In such a state, as shown in
In this case, in the one pressing mechanism 127a, the piston rod 131 is made to protrude (bearing housing 129 is made to advance) until the rotation center of the flexible shaft 128 coincides with the rotation central axis 67. At the same time, in the other pressing mechanism 127b, the piston rod 131 is made to protrude (bearing housing 129 is made to advance) until the rotation center of the flexible shaft 128 coincides with the second rotation central axis 13r.
Thereby, the second roll 13 is kept in a state where the second roll 13 is supported on the third bearing mechanism 17 and the fourth bearing mechanism 18 at both ends thereof with good balance.
Furthermore, in the one pressing mechanism 127a, the whole of the pressing force exerted on the flexible shaft 128 is completely absorbed and removed by the elastic shaft coupling 120 (more specifically, elastic body 126) being elastically deformed. Accordingly, the changed state of the second roll 13 is never transmitted to the second motor 57 (second rotating shaft part 65).
According to this embodiment, the second power transmission mechanism 95 of this embodiment is further provided with, in addition to the elastic shaft coupling 120, the pressing mechanisms 127a and 127b. Thereby, the whole of the changed state (for example, angular deviation (eccentricity, deflection angle) of the second rotation central axis 13r) occurring in the second roll 13 is completely absorbed and removed. Accordingly, the changed state of the second roll 13 is never transmitted to the second motor 57 (second rotating shaft part 65). At the same time, the posture of the second motor 57 (rotor 59) or the second rotating shaft part 65, i.e., the posture of the rotation central axis 67 is maintained constant at all times.
Thus, the rotating state of the second motor 57 is not changed, and is transmitted to the second roll 13 as it is, whereby the second power transmission mechanism 95 which makes the second roll 13 rotate with the timing identical to the rotating state of the second motor 57 is realized. It should be noted that other advantages are identical to the first embodiment, and hence descriptions of them are omitted.
Regarding the aforementioned first drive mechanism 53, in a specification which enables the first motor 56 directly contributing to the rotation of the first roll 12 to generate high torque at a low rotational speed, in place of the first power transmission mechanism 72, the second power transmission mechanism 95 of the sixth embodiment may be applied.
In the sixth embodiment described above, although the supporting structure of the elastic shaft coupling 120 has not been particularly mentioned, for example, the elastic shaft coupling 120 may be rotatably supported on the stays 121 (bearings 122) of the fifth embodiment described previously. In this case, regarding the arrangement of the stays 121, the stays 121 are made to stand on the base 30.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2016-071980 | Mar 2016 | JP | national |
| 2016-176894 | Sep 2016 | JP | national |
| 2016-239573 | Dec 2016 | JP | national |
