JP5524001B2 - Pellet manufacturing method and pellet manufacturing apparatus - Google Patents

Description

  The present invention relates to a pellet manufacturing method and a pellet manufacturing method in which a molten resin is extruded from a die in a strand shape and cooled in water, and the cooled resin is cut by a cutter blade that rotates while contacting the surface of the die to manufacture a pellet. It relates to the device.

  As is well known in the art, a synthetic resin material in which additives such as a stabilizer, a plasticizer, and an inorganic filler are mixed and dispersed is used for molding a synthetic resin molded product. Such a synthetic resin material is generally pelletized. The pelletizer, that is, the pellet manufacturing apparatus is composed of an extruder, a die provided at the tip of the extruder, a cutter device provided corresponding to the die, and the like. The cutter device and the die are placed in a predetermined casing. ing. The casing is supplied with cooling water or warm water from a predetermined water supply port and drains from the predetermined water discharge port. Therefore, when a molten resin mixed with various additives by an extruder and melted and kneaded is continuously extruded in a strand form from a plurality of nozzle holes of the die, the resin is cooled in water and is kept in contact with the die at a predetermined speed. When the cutter is rotated by the cutter device, pellets of a predetermined size are obtained. The obtained pellets are discharged together with water from the drain. In such a pellet manufacturing apparatus, the contact state of the cutter blade with the die is important. That is, when the contact surface pressure between the die and the cutter blade is reduced, a gap, that is, a clearance is generated between the die and the cutter blade, or the so-called cutter blade regenerating effect in which the cutter blade is properly polished is lost. If it does so, the shape and particle size of a pellet will become non-uniform | heterogenous by cutting failure, and will have a bad influence on quality. In addition, if the cutter blade is strongly pressed against the die and the contact surface pressure between the die and the cutter blade becomes too high, the die and the cutter blade are worn out early. In view of this, various pellet manufacturing apparatuses that can appropriately abut the cutter blade on the die have been proposed.

JP 2000-301532 A JP 2003-326519 A Japanese Patent No. 2642579 US Pat. No. 5,624,688 Japanese Patent Publication No.54-127463 Japanese Patent Publication No. 07-20618

  In Patent Document 1, a cutter holder that fixes a plurality of cutter blades is connected to a cutter shaft via a predetermined joint, and the cutter holder can swing in a predetermined range with respect to the cutter shaft. A pellet manufacturing apparatus equipped with the apparatus is described. The cutter holder can be tilted in any direction within a specified range with respect to the cutter shaft. In other words, even if the perpendicularity between the cutter shaft and the surface of the die is insufficient, in other words, the surface and the die comprising a plurality of cutter blades Even if the surface parallelism is insufficient, the cutter holder is slightly inclined with respect to the cutter axis, and the plurality of cutter blades properly come into contact with the die. Also in Patent Documents 2 to 4, the cutter holder is connected to the cutter shaft so as to be able to swing within a predetermined range, thereby producing a pellet having a cutter device that has the same effect as the pellet manufacturing device described in Patent Document 1. An apparatus is described.

  Patent Document 5 includes a cutter device including a cutter holder fixed to a cutter shaft, a plurality of cutter arms connected to the cutter holder, and a plurality of cutter blades connected to the respective cutter arms. A pellet production apparatus is described. A plurality of holes having a predetermined depth in the axial direction are formed at equal intervals in the circumferential direction on the outer peripheral surface of the cutter holder. Cutter arms are inserted into these holes. The cutter arm is formed of an axis having a predetermined cross section in a circle, and is bent at a right angle at a predetermined position to form an L shape. Then, one end is inserted into the hole of the cutter holder and is prevented from coming out of the hole by a predetermined pin. The other end of the cutter arm is directed to the die at a predetermined oblique angle. Since one end can rotate within a predetermined range within the hole, the other end of the cutter arm can rotate within a predetermined range. Since the distance between the other end and the die is changed by this rotation, the pellet blade connected to the other end can move up and down to follow the unevenness even if the surface of the die has unevenness. . The cutter blade is composed of a blade portion in which a blade having a predetermined length is formed, and a shaft portion fixed to the center portion of the blade portion at a right angle to the blade portion. The shaft portion is connected to the other end portion of the cutter arm so as to extend the cutter arm, and can be rotated with respect to the cutter arm. Therefore, the blade portion of the pellet blade can be rotated in a plane perpendicular to the cutter arm. Since the cutter device is configured in this way, the cutter blade can follow the curvature of the surface of the die even if the surface of the die is curved, and the cutter blade smoothly contacts the surface of the die. .

  Patent Document 6 describes a pellet manufacturing apparatus including a cutter device that can drive a cutter shaft in the axial direction by hydraulic pressure and adjust a contact surface pressure between a die and a cutter blade. When the cutter blade rotates in water, a water flow hits the cutting edge of the cutter blade, a so-called rake face, and the cutter blade is pressed against the die. When the cutter blade rotates at a high speed, the cutter blade is strongly pressed against the die and the contact surface pressure between the die and the cutter blade increases, but in the pellet manufacturing apparatus described in Patent Document 6, axial force is applied to the cutter shaft. Since it can be made to act, the contact surface pressure of a die | dye and a cutter blade can be reduced.

  In any of the pellet manufacturing apparatuses described in Patent Documents 1 to 6, the cutter blade is relatively appropriately brought into contact with the surface of the die, so that pellets having a desired quality can be manufactured. However, these pellet manufacturing apparatuses also have problems to be solved. For example, in the pellet manufacturing apparatus described in each of Patent Documents 1 to 4, when the flatness of the surface composed of a plurality of cutter blades and the surface of the die is sufficient, the parallelism of these surfaces is insufficient. However, if the cutter holder is tilted with respect to the cutter axis and the cutter blade can properly abut the die, the flatness of these surfaces may be insufficient. The cutter blade of the part is brought into contact with the die with an excessive contact surface pressure. As a result, there is a problem in that the quality of pellets produced due to poor cutting is adversely affected, and the dies and cutter blades wear quickly.

  A problem to be solved can also be found in the pellet manufacturing apparatus described in Patent Document 5. In other words, even if the flatness of the surface of the die is insufficient, the cutter blade will follow the shape of the surface of the die, but the problem when the rotational speed of the cutter blade changes is exceptional. Not taken into account. That is, when the cutter blade rotates at a low speed, since the water flow hits the rake face of the cutter blade is small, the force with which the cutter blade is pressed against the die is weakened. Then, the contact surface pressure between the die and the cutter blade becomes insufficient, a clearance is generated between the die and the cutter blade, and the regenerating effect of the cutter blade cannot be obtained, resulting in a cutting failure. Also, when the cutter blade rotates at a high speed, the water flow that hits the rake face of the cutter blade increases, so that the cutter blade is strongly pressed against the die, the contact surface pressure between the die and the cutter blade becomes excessive, and the cutter blade becomes Wear out.

  According to the pellet manufacturing apparatus described in Patent Document 6, since the contact surface pressure between the die and the cutter blade is controlled by the pressure medium, there is no particular problem in normal implementation, but a plurality of cutter blades are fixed to the cutter holder. Since the cutter holder is also fixed to the cutter shaft, the parallelism between the surface of the plurality of cutter blades and the surface of the die may be insufficient. If the flatness is insufficient, some cutter blades may float from the die, or some cutter blades may come into contact with the die with excessive contact pressure.

  An object of the present invention is to provide a pellet manufacturing method and a pellet manufacturing apparatus that solve the above-described problems, and specifically, even if the flatness of the surface of the die is insufficient, or Even if the perpendicularity between the surface of the die and the cutter axis is insufficient, the cutter blade can be properly brought into contact with the surface of the die, and the die and cutter blade can be brought into contact with each other regardless of the rotational speed of the cutter blade. An object of the present invention is to provide a pellet manufacturing method and a pellet manufacturing apparatus capable of maintaining the contact surface pressure within an appropriate range.

  In order to achieve the above object, according to the present invention, in the cutter device of the pellet manufacturing apparatus, the cutter blades are individually swingably attached to the cutter holder so that each cutter blade abuts against the surface of the die independently. To. Also, when producing pellets by rotating the cutter shaft, an axial force is applied to the cutter shaft according to the number of rotations so that the contact surface pressure between the die and the cutter blade is adjusted to an appropriate range. .

Thus, a first aspect of the present invention, in order to achieve the above object, when producing pellets by cutting the molten resin extruded from a die into water or hot water in a strand form into a predetermined size, at a predetermined speed A cutter shaft that is rotationally driven, a cutter holder that is detachably attached to the tip of the cutter shaft , and a plurality of cutter blades provided on the cutter holder. A first pivot that is swingably pivotable with respect to a first axis extending radially outwardly in parallel with the bottom surface of the cutter holder facing the die side and perpendicular to the first axis. A cutter device attached so as to be swingably pivotable with respect to the second axis is also used, and the pivoting with respect to the first axis in the cutter device is restricted by a predetermined member, whereby a predetermined Within the rotation range of Passively so as pivot is allowed only slight rotation by elastic deformation of acceptable one said member Once beyond the the pivoting range, and according to the rotational speed of the cutter shaft to the cutter shaft It is configured to apply a predetermined axial force.

According to a second aspect of the present invention, there is provided a pellet manufacturing apparatus including a cutter device for cutting a molten resin extruded into water or warm water in a strand form from a die into a predetermined size, wherein the cutter device is rotationally driven at a predetermined speed. A cutter shaft, a cutter holder that is detachably attached to a tip end portion of the cutter shaft, a plurality of cutter arms that are radially attached to an outer peripheral portion of the cutter holder, and attached to each of these cutter arms A plurality of cutter blades, and a pressing force adjusting mechanism for applying an axial force to the cutter shaft, wherein the cutter arm is parallel to the bottom surface of the cutter holder facing the die side and radially out of the radius. Write pivoting range by pivotally predetermined amount extend Rutotomoni predetermined member is restricted to, no resistance is within a predetermined range of rotation Turning slightly rotated by the elastic deformation of the member Once beyond the the pivoting range is permitted with is allowed, the cutter blade is rockingly times around a vertical axis relative to said cutter arm The plurality of cutter blades follow the shape of the surface of the die, and the pressing force adjusting mechanism is arranged on the cutter shaft with a predetermined speed corresponding to the rotational speed of the cutter shaft. It is configured to apply an axial force.

  As described above, according to the present invention, the plurality of cutter blades can individually swingably rotate with respect to the first axial center extending radially outward in parallel with the bottom surface of the cutter holder. In addition, the cutter blades are attached so as to be swingably rotatable with respect to the second axis perpendicular to the first axis, so that each cutter blade independently follows the shape of the surface of the die. Touch. Therefore, even if the flatness of the surface of the die is insufficient, there is no clearance between the die and the cutter blade. Thereby, a high quality pellet can be manufactured in shape. In addition, since a force in a predetermined axial direction corresponding to the rotational speed of the cutter shaft is applied to the cutter shaft, the contact surface pressure between the die and the cutter blade does not become excessive or excessive. Therefore, the cutter blade is properly polished and does not wear prematurely. According to another invention, since the range of the swinging rotation angle of the cutter arm is limited, an axial force is appropriately applied to the cutter shaft so that the contact surface pressure between the die and the cutter blade is increased. It can be adjusted appropriately.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows typically the cutter apparatus which concerns on embodiment of this invention, The (a) is a side view of the cutter holder and cutter blade seen from the die | dye side, The (a) is sectional drawing of a cutter holder and a cutter blade. . BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows typically the cutter blade and cutter arm which comprise the cutter apparatus which concerns on this Embodiment, The (a) is a front view of a cutter blade, The (i) is a side view of a cutter blade, (C) is a front view of the cutter arm, (d) is a side view of the cutter arm, (v) and (f) are cross-sectional views cut along B-B and A-A in (c), respectively. ) Is a front view of the assembled cutter blade and cutter arm. It is a front view which shows typically the pellet manufacturing apparatus which concerns on this Embodiment. In the pellet manufacturing apparatus which concerns on embodiment of this invention, it is a graph which shows the relationship between the contact surface pressure etc. of the dice | dies and the cutter blade with respect to the rotation speed of a cutter shaft, The (a) is the rotation speed of a cutter shaft, and a cutter shaft. The relationship between the propulsive force acting, (a) is the relationship with the adjustment pressure that is applied to the cutter shaft by the pressing force adjustment mechanism, and (C) is the relationship between the contact surface pressure between the die and the cutter blade, respectively. It is a graph which shows.

  Embodiments of the present invention will be described below. As shown in FIG. 3, the pellet manufacturing apparatus 1 according to the present embodiment is configured substantially in the same manner as a conventionally known pellet manufacturing apparatus. That is, it is comprised from the extruder which extrudes molten resin, the die | dye 2 provided at the front-end | tip of an extruder, and the cutter apparatus 5 to which the cutter blade 4,4, ... is attached. The extruder is not shown in FIG. The cutter device 5 includes a cutter shaft 7 that is rotationally driven by a drive mechanism (not shown), a cutter holder 8 that is detachably attached to a front end portion of the cutter shaft 7, and a plurality of cutter blades provided in the cutter holder 8. Are composed of a pressing force adjusting mechanism 9 for adjusting the pressure at which the cutter blades 4, 4,... Abut against the die 2, that is, the contact surface pressure, by applying an axial force to the cutter shaft 7. . The pressing force adjusting mechanism 9 will be described in detail later.

  In the present embodiment, eight mounting holes 13, 13,... Are formed at equal intervals in the circumferential direction on the outer peripheral surface of the mounting portion 8a of the cutter holder 8. These mounting holes 13, 13,... Are mounting holes having a predetermined depth parallel to the bottom surface 8 b of the cutter holder 8 and directed radially inward. A female screw is formed on the inner peripheral surface of these holes 13, 13, ... so that one end of the cutter arm 11 is screwed. A plurality of female screws for attaching a fixing plate, which will be described later, are formed on the front surface or the bottom surface 8b of the cutter holder 8.

  The fixing plate 32 attached to the bottom surface 8b of the cutter holder 8 has a disk shape as a whole as shown in FIG. 1A, and a hole for inserting the attachment bolt 35 is formed at the center thereof. A plurality of through holes for mounting screws 33, 33,... Are formed at predetermined positions away from the center. A locking portion 32S bent to the cutter holder 8 side is formed on the circumferential portion of the fixing plate 32 in which such a through hole is formed. When the locking portion 32S is assembled as shown in FIG. 1 (a), the locking portion 32S is positioned on the outer peripheral portion of the cutter holder 8, and its tip portion is placed on a locking surface of a cutter arm described later with a predetermined play. It comes to contact with.

  In the present embodiment, the cutter blades 4, 4,... Are attached to the cutter holder 8 via respective cutter arms. A side view or a bottom view of the cutter holder 8, the cutter blades 4, 4,..., Etc. viewed from the die side is shown in FIG. 1A, and a cross-sectional view showing these in section is shown in FIG. Yes. FIG. 2 shows the cutter blade 4 and the cutter arm 11. The cutter blade 4 and the cutter arm 11 will be described in detail with reference to these drawings.

  As shown in FIGS. 2A and 2A, the cutter blade 4 includes a blade portion 15 in which a cutting blade 14 is formed and a shaft portion 17 having a circular cross-sectional shape. . The center of the blade portion 15 is integrally attached to the tip portion of the shaft portion 17. In other words, the shaft 17 is connected to the center of the groove 18 of the cutter blade 4 so as to be perpendicular to the groove 18. The cutter blade 4 configured as described above is attached to a cutter arm 11 described later by a shaft portion 17 thereof. A groove 19 is formed on the outer peripheral surface in the vicinity of the head portion of the shaft portion 17, and a snap ring 30 is fitted into the groove 19.

  As shown in the front view of (c) in FIG. 2 and the side view of (d) in FIG. 2, the cutter arm 11 is roughly shaped like a rod or column with a circular cross section. Since it has a columnar shape, machining is easier than a bent member. From one end 21 to the center of the cutter arm 11, an insertion portion 22 is inserted into the mounting hole 13 of the cutter holder 8. More specifically, a male screw is formed on the outer peripheral portion of the insertion portion 22, and this male screw is loosely screwed into a female screw formed on the inner peripheral surface of the mounting hole 13. Since the screw is loosely screwed in this way, the cutter arm 11 can rotate in the mounting hole 13. Near the center of the cutter arm 11, as shown in the cross-sectional view of FIG. 2 (f), a locking surface 24 is formed in such a manner that a part of the outer peripheral surface is cut off in a planar shape. . The locking surface 24 has a predetermined length in the axial direction as shown in FIG. When the cutter arm 11 is inserted or screwed into the attachment hole 13 of the cutter holder 8 and the fixing plate 32 is attached to the cutter holder 8 as will be described later, the engagement portion 32S formed on the attachment plate 32 makes this engagement. The surface 24 is pressed. Thereby, the rotation of the cutter arm 11 is restricted and stopped in the mounting hole 13. Further, since the locking surface 24 is pressed by the locking portion 32S, the range of the rotation angle in which the cutter arm 11 can rotate in the axial direction is limited to a predetermined range. Accordingly, the cutter blade 4 attached to the cutter arm 11 can swing in a direction in contact with the die 2 surface and in a direction away from the die 2, but the range in which the cutter blade 4 can swing is limited.

  In the vicinity of the other end portion 26 of the cutter arm 11, a part of the outer peripheral surface is cut out in parallel from both sides over a predetermined length in the axial direction to form a flat plate portion 27 composed of surfaces 27 ′ and 27 ′. As shown in FIG. 2E, a through hole 28 is vertically opened in the flat plate portion 27. The shaft portion 17 of the cutter blade 4 is inserted into the through hole 28. The cutter arm 11 and the cutter blade 4 are inserted into the through-hole 28 of the shaft portion 17 of the cutter blade 4 so that the groove 19 formed in the shaft portion 17 is inserted into the groove 19 as shown in FIG. The snap ring 30 is assembled by fitting. The inner diameter of the through hole 28 is slightly larger than the outer diameter of the shaft portion 17 of the cutter blade 4. Thereby, the axial part 17 can be rotated to an axial direction. Therefore, the cutter blade 4 can freely rotate in the vertical direction with respect to the cutter arm 11. Incidentally, since the locking surface 24 of the cutter arm 11 is inclined at a predetermined angle with respect to the surfaces 27 ′ and 27 ′ of the flat plate portion 27, the cutter arm 11 to which the cutter blade 4 is attached is attached to the cutter holder 8. Then, the cutter blade 4 is inclined at a predetermined angle with respect to the bottom surface of the cutter holder 8. That is, the cutter blade 4 comes into contact with the die at a predetermined angle.

  Next, an assembly method for attaching the cutter arm 11 to which the cutter blade 4 is attached to the cutter holder 8 will be described. As shown in FIGS. 1A and 1A, the cutter arms 11, 11,... Are screwed into the mounting holes 13, 13,. At this time, the locking surfaces 24, 24, ... of the cutter arms 11, 11, ... are stopped at a position facing the bottom surface 8b side of the cutter holder 8. The fixing plate 32 is applied to the bottom surface 8 b of the cutter holder 8, and the mounting bolt 35 is screwed into the female screw at the tip of the cutter shaft 7. Further, the mounting screws 33, 33,... Are screwed into the cutter holder 8. This completes the assembly. The locking portions 32S of the fixing plate 32 press the locking surfaces 24, 24,... Of the cutter arms 11, 11,. Therefore, the cutter arms 11, 11,... Are restricted from rotating and do not come out of the mounting holes 13, 13,. Moreover, since it hold | suppresses by the latching step 32S, the range of the rotation angle of the rotation Y1 of the axial direction of the cutter arm 11, 11, ... in the attachment holes 13,13, ... will be restrict | limited. More specifically, the cutter arms 11, 11,... Rotate in the axial direction without resistance within a predetermined rotation range in which the locking portion 32S is separated from the locking surfaces 24, 24,. However, since the fixing plate 32 is slightly elastically deformed, it can be slightly rotated against the elastic deformation even when the rotation range is exceeded.

  A pressing force adjusting mechanism 9 that applies an axial force to the cutter shaft 7 will be described with reference to FIG. The pressing force adjusting mechanism 9 includes a support mechanism for the cutter shaft 7 and a fluid supply / discharge mechanism that supplies / discharges compressed air or pressurized oil to / from the support mechanism. First, the support mechanism will be described. In the cutter device 5 according to the present embodiment, the support mechanism includes a sleeve 36 that surrounds the cutter shaft 7 and a housing 39 that similarly surrounds the sleeve 36. The cutter shaft 7 has a large-diameter portion 7a having a predetermined length. The cutter shaft 7 is pivotally supported by the bearing portion of the sleeve at two locations before and after the end of the large diameter portion 7a. Since the front and rear ends of the large-diameter portion 7a are in contact with the bearing portion of the sleeve 36, the cutter shaft 7 is freely rotatable with respect to the sleeve 36, but the movement in the axial direction is restricted by the sleeve 36. Yes. An enlarged diameter portion having a predetermined width is formed on the outer peripheral portion near the rear end portion of the sleeve 36. This enlarged diameter portion serves as a piston portion 37 of the pressing force adjusting mechanism 9 as will be described later.

  The housing 39 includes a cylindrical portion in which the sleeve 36 is inserted in a liquid-tight manner so as to be movable in the axial direction, and a cylinder portion 41 in which a piston portion 37 of the sleeve 36 is similarly liquid-tightly positioned so as to be movable in the axial direction. It has become. The end of the cylinder portion 41 is sealed with a lid. The cylinder portion 41 is partitioned by the piston portion 37 into a front second cylinder chamber 45 located on the die 2 side and a rear first cylinder chamber 44. Compressed air is supplied to and discharged from the second cylinder chamber 45, and pressurized oil is supplied to and discharged from the first cylinder chamber 44. When hydraulic pressure or air pressure is supplied to or discharged from the first and second cylinder chambers 44 and 45, the piston / cylinder portion 42 is operated and the housing 39 is fixed. Therefore, the sleeve 36 and therefore the cutter shaft 7 are driven in the axial direction. Alternatively, a predetermined axial force is applied to the cutter shaft 7. The cylinder part 41 and the piston part 37 work together to constitute a piston / cylinder part 42.

  The fluid supply / discharge mechanism includes an air source 46, an air filter 48, first and second pressure reducing valves 49 and 50, first and second switching valves 51 and 52, and the like. The first switching valve 51 can take two positions of X and Y, and when the X position is taken, compressed air is supplied to the hydroconverter 54. The hydroconverter 54 is a device that converts air pressure into hydraulic pressure, and an outlet port of the hydroconverter 54 and the first cylinder chamber 44 are connected by a supply / discharge pipe 56. When the first switching valve 51 takes the Y position, the compressed air supplied from the air source 46 is shut off. Alternatively, the pressure oil is discharged from the first cylinder chamber 44. As a result, the hydraulic pressure in the first cylinder chamber 44 decreases. On the other hand, the second switching valve 52 can also take two positions, X and Y. When the Y position is adopted, the compressed air from the air source 46 is shut off and the second cylinder chamber 45 is released to atmospheric pressure. Will be. When the second switching valve 52 is set to the X position, the compressed air is directly supplied to the second cylinder chamber 45 via the supply / discharge pipe 57. Pressure gauges 58 and 59 are attached to the supply and discharge pipes 56 and 57, respectively, and it is monitored whether the air pressure or the hydraulic pressure is maintained in an appropriate range.

  According to the present embodiment, although not shown in the figure, the cutter shaft 7 is provided with a rotational speed meter, and the rotational speed of the cutter shaft 7 measured by this rotational speed meter is input to the control device, and According to the rotational speed of the cutter shaft 7, the pressure reducing valves 49, 50, the switching valves 51, 52, etc. are controlled as described below.

  The operation of the pellet manufacturing apparatus 1 according to the present embodiment will be described. In the pressing force adjusting mechanism 9, the first switching valve 51 of the fluid supply / discharge mechanism is set to the X position, the second switching valve 52 is set to the Y position, and a predetermined axial force in the dice 2 direction is applied to the cutter shaft 7. The cutter shaft 7 is rotationally driven by a predetermined rotational drive mechanism. Then, the cutter blades 4, 4,... Abut on the die 2 and rotate. When the resin material is melted by the extruder and extruded from the die 2 in a strand shape, the die 2 is submerged in water or warm water, so that the molten resin is cooled in water. The cooled resin is cut by rotating cutter blades 4, 4,... To obtain pellets. At this time, since a water flow strikes the so-called rake face of the blade portion 15 of the cutter blades 4, 4,..., A propulsive force acts on the cutter blades 4, 4,. Then, since the cutter blades 4, 4,... Are swingably attached to the cutter holder 8, the cutter blades 4, 4,... Come into contact with the die 2 so as to follow the shape of the surface of the die 2. . Further, since an appropriate axial force is applied to the cutter shaft 7 by the pressing force adjusting mechanism 9, the contact surface pressure between the die 2 and the cutter blades 4, 4,... Is maintained in an appropriate range. Therefore, there is no clearance between the die 2 and the cutter blades 4, 4,..., And the resin can be cut well.

  When the rotational speed of the cutter shaft 7 is large or large, a water flow hits the rake face of the cutter blades 4, 4,... At high speed, and the thrust force f2 in the direction of the die 2 acting on the cutter blades 4, 4,. However, the rotation speed measured by the tachometer is input to the control device, the second switching valve 52 is switched to the X position by the signal from the control device, and the compressed air adjusted by the second pressure reducing valve Is supplied to the second cylinder chamber 45. Then, an axial force f3 that attempts to separate the cutter blades 4, 4, ... from the die 2 acts on the cutter shaft 7. Since the contact surface pressure f1 between the die 2 and the cutter blades 4, 4,... Is given by f1 = f2-f3, the magnitude of the force f3 is adjusted, and the contact surface pressure f1 is maintained at an appropriate pressure. When the cutter shaft 7 further increases in speed, the propulsive force f2 acting on the cutter blades 4, 4,... Further increases, but the first switching valve 51 is switched to the Y position, and the pressure oil in the first cylinder chamber 44 is increased. Is discharged. Then, since the axial force f3 acting on the cutter shaft 7 increases, the contact surface pressure f1 between the die 2 and the cutter blades 4, 4,... Is maintained in an appropriate range.

  As shown in the graph of FIG. 4A, when the rotational speed of the cutter shaft 7 increases, the propulsive force f2 acting on the cutter blades 4, 4,. Therefore, as shown in FIG. 4A, the pressing force adjusting mechanism 9 changes the axial force f3 acting on the cutter shaft 7 in accordance with the rotational speed of the cutter shaft 7. Then, as shown in FIG. 4C, the contact surface pressure f1 between the die 2 and the cutter blades 4, 4,... Is kept constant regardless of the rotational speed of the cutter shaft 7.

  The embodiment of the present invention can be variously modified. For example, with respect to the pressing force adjusting mechanism 9, the working fluid can be composed only of pressurized oil, can be composed only of compressed air, or the mechanism described in Patent Document 6 can be applied. Further, the cutter holder and the cutter blade can be modified, and the cutter holder and the cutter blade described in Patent Document 5 can be applied.

DESCRIPTION OF SYMBOLS 1 Pellet manufacturing apparatus 2 Dies 4 Cutter blade 5 Cutter apparatus 7 Cutter shaft 8 Cutter holder 8a Mounting part 8b Bottom surface 9 Pushing force adjustment mechanism 11 Cutter arm 24 Locking surface 32 Fixing plate
32S locking part

Claims (2)

When producing pellets by cutting a molten resin extruded into water or warm water in a strand form from a die into a predetermined size,
A cutter shaft that is rotationally driven at a predetermined speed, a cutter holder that is detachably attached to the tip of the cutter shaft , and a plurality of cutter blades provided on the cutter holder, the plurality of cutter blades to but individually, first rocking dynamically rotatably with respect to the axis extending radially outward radially parallel to the bottom surface of the cutter holder facing the die side, and the first axis Using a cutter device that is swingably pivotably attached to a vertical second axis,
In the cutter device, the rotation with respect to the first axis is restricted by a predetermined member, whereby the rotation is allowed without resistance within a predetermined rotation range, but when the rotation range is exceeded, the member Allow only slight rotation due to elastic deformation of
The pellet manufacturing method is characterized in that a force in a predetermined axial direction corresponding to the rotational speed of the cutter shaft is applied to the cutter shaft. In a pellet manufacturing apparatus equipped with a cutter device that cuts a molten resin extruded into water or warm water in a strand form from a die into a predetermined size,
The cutter device includes a cutter shaft that is rotationally driven at a predetermined speed, a cutter holder that is detachably attached to a tip portion of the cutter shaft, and a plurality of cutter arms that are radially attached to an outer peripheral portion of the cutter holder. And a plurality of cutter blades attached to each of these cutter arms, and a pressing force adjusting mechanism for applying an axial force to the cutter shaft,
The cutter arm rotation range is restricted only by extending Rutotomoni predetermined member a predetermined amount so as to be rotatable radially outwardly radially parallel to the bottom surface of the cutter holder facing the die side, within a predetermined rotation range Is allowed to rotate without resistance and slightly allowed to rotate by elastic deformation of the member when the rotation range is exceeded,
The cutter blade is swingably pivotable about a vertical axis with respect to the cutter arm, whereby the plurality of cutter blades follow the shape of the surface of the die,
2. The pellet manufacturing apparatus according to claim 1, wherein the pressing force adjusting mechanism applies a force in a predetermined axial direction corresponding to a rotation speed of the cutter shaft to the cutter shaft.

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