JP5564010B2 - Cutter blade and pellet manufacturing apparatus of pellet manufacturing apparatus - Google Patents

Description

  The present invention relates to a cutter blade of a pellet manufacturing apparatus and a pellet manufacturing apparatus. Specifically, the present invention relates to a die attached to a discharge chamber at a downstream end of an extruder or an extrusion nozzle continuously in cooling water in a strand shape. The present invention relates to a cutter blade that rotates a molten resin to be extruded while being in contact with the surface of the die, and cuts the molten resin into a predetermined size in cooling water, and a pellet manufacturing apparatus including the cutter blade.

  For molding a synthetic resin molded article, as is conventionally known, a molding material in which additives such as a stabilizer, a plasticizer, and an inorganic filler are mixed and dispersed in a synthetic resin is used. Such a molding material is generally pelletized. A pelletizer, that is, a pellet manufacturing apparatus, includes an extruder, a die provided at a discharge end of the extruder, a cutter device provided corresponding to the die, and the like. Therefore, when the resin continuously extruded in a strand form from a plurality of nozzle holes of the die is cut with a cutter blade of a cutter device that is rotationally driven at a predetermined speed, a pellet having a predetermined length is obtained. An underwater cutting method is known as a manufacturing method of such a pellet. In the underwater cutting method, the synthetic resin and the specified additives are supplied to the extruder, melted and kneaded, and immediately after being extruded in the form of a strand from the die into the cooling water, and rotated with the cutter blade in direct contact with the die surface. This is a method of cutting underwater, also called a hot cut method. Such an underwater cut type pellet manufacturing apparatus has been proposed in various ways by the present applicant, and Patent Document 1 can be cited as a prior art document.

JP 2010-740

  The pellet manufacturing apparatus shown in Patent Document 1 includes an extruder and a cutter apparatus. Although not shown in the figure, the extruder is constituted by a cylinder barrel and a screw provided in the cylinder barrel so as to be capable of rotational driving, as is conventionally known. A die is attached to the tip of the cylinder barrel. On the back side of this die, as shown in part (a) of FIG. 5, a ring-shaped extrusion nozzle 40 is provided. The cross-sectional shape of the ring-shaped extrusion nozzle 40 is substantially trapezoidal, and a plurality of nozzle holes 41, 41,... Communicating with the bore of the cylinder barrel are opened on the top surface or the surface 40m.

  On the other hand, although not shown in the drawing, the cutter device is composed of a cutter shaft that is rotatably provided in the housing, a cutter holder fixed to the tip of the cutter shaft, and the like. A plurality of cutter blades 50, 50,... Are attached. As shown in the perspective view of FIG. 5A, the cutter blade 50 has a substantially rectangular parallelepiped shape, a blade portion 50a having a constant thickness in the length direction, and an attachment portion 50b attached to the cutter holder. It is composed of The front side of the blade portion 50a includes a top surface 50i and an inclined surface that is inclined so as to become thinner from the top surface 50i toward the tip portion in the rotation direction, that is, a rake face 50k, and the tip portion of the rake face 50k is formed. The cutting edge is 50h. The bottom surface on the back side of the blade portion 50a is a contact surface 50s in which a surface having a predetermined width from the blade edge 50h is rotationally driven in contact with the surface 40m of the extrusion nozzle 40. A concave relief 50j having a predetermined depth is formed behind the contact surface 50s. Two bolt insertion holes 50c and 50c are opened in the mounting portion 50b. A plurality of cutter blades 50, 50,... Configured as described above are detachably attached to the cutter holder with bolts. A part of the state of attachment is shown in FIG.

  A die, an extrusion nozzle 40, cutter blades 50, 50,..., A cutter holder, and the like are housed in a cutter case filled with cooling water. Therefore, the die, the extrusion nozzle 40, the cutter blades 50, 50,... Are submerged in the cooling water.

  Since the conventional pellet manufacturing apparatus is configured as described above, when the extruder screw is rotationally driven while supplying cooling water into the cutter case, the melted resins 41s, 41s, etc. are conventionally known. In this way, the extrusion nozzle 40 is extruded in a strand form from a plurality of nozzle holes 41, 41,. At this time, when the cutter shaft is rotated while being pressed in the direction of the extrusion nozzle 40 by a driving device not shown in the drawing, the cutter blades 50, 50,... Are rotated while being in contact with the surface of the extrusion nozzle 40. The molten resin 41s, 41s,... Extruded continuously is cut in the cooling water by the cutter blades 50, 50,. As a result, a pellet having a predetermined thickness and a predetermined length is obtained. After the pellets are discharged from the cooling water discharge port together with the cooling water, the product is obtained by separating from the cooling water and drying.

  By the way, according to the invention described in Patent Document 1, the rake face 50k of the cutter blade 50 is configured such that the tip side is wider than the root side on the mounting portion 50b side. Since the reaction force received from the cooling water is configured to increase at the tip end side when being driven by rotation, the pressing pressure applied through the cutter holder and the reaction force applied from the cooling water to the cutter blade 50 are reduced. The point of action of the resultant force of 1 moves or moves toward a substantially central point in the longitudinal direction of the blade part 50a.

  On the other hand, a second resultant force acts on the cutter blade 50 from the surface 40m of the extrusion nozzle 40 as a reaction force of the first resultant force. The action point of the second resultant force is substantially the longitudinal direction of the blade portion 50a. The center point. That is, since the action points of the first and second resultant forces coincide with each other, no bending moment is generated in the cutter blade 50. Therefore, according to the invention described in Patent Document 1, there is a gap between the cutter blade 50 and the surface of the extrusion nozzle 40 even if the blade portion 50a of the cutter blade 50 is long in the axial direction or long in the radial direction. It never happens. Therefore, an excellent effect that a high-quality pellet having a uniform particle diameter can be produced is obtained. Moreover, even if the blade part 50a is long in the axial direction, the pellet manufacturing apparatus can be enlarged because it is not elastically deformed. Further, the blade portion 50a is thicker on the tip side than the root side on the mounting portion 50b side, and the top surface 50i is narrower on the tip side than the root side on the mounting portion 50b side. Even if the part side is not made extremely thick, the rake face 50k is widened, and the same effect can be obtained and implemented effectively.

  However, there are also problems to be improved. That is, (a) of FIG. 5 is a schematic side view of the cutter blade 50 shown in Patent Document 1 described above and a conventional general cutter blade. As shown in FIG. Since the contact surface 50s of the blade part 50a is rotationally driven in contact with the surface 40m of the extrusion nozzle 40, the contact surface 50s of the blade part 50a and the surface 40m of the extrusion nozzle 40 are in metal contact by the pressure received from the cooling water. These may wear out. Hereinafter, the reason will be described on the assumption that the cooling water flows. In FIG. 5A, the streamline r1 in the vicinity of the surface 40m of the extrusion nozzle 40 extends from the left to the right parallel to the surface of the extrusion nozzle 40, and upwards in the vicinity of the rake face 50k of the cutter blade 50. Is changed and flows to the rear of the cutter blade 50. The flow of the cooling water farther from the surface 40m of the extrusion nozzle 40 than the stream line r1 is indicated by stream lines r2 and r3. When the flow rate of the cooling water flowing in this way is Qa with respect to the unit length in the direction perpendicular to the drawing, Qa flows at an average flow velocity v1 in parallel with the extrusion nozzle 40 at a position upstream of the cutter blade 50, It flows at an average flow velocity v2 in the vicinity of the rake face 50k. Due to the change in momentum (Qa) · (v1-v2) caused by the change in the flow of the cooling water, a downward reaction is attempted to press the cutter blade 50 against the rake face 50k of the cutter blade 50 against the surface 40m of the extrusion nozzle 40. A force Pa is generated. Thereby, the contact surface 50s of the blade part 50a and the surface 40m of the extrusion nozzle 40 are worn by metal contact.

  Further, since the rear end portion of the cutter blade 50 is substantially perpendicular to the flow of the cooling water, vortices U, U,... Are generated, but the inside of the vortices U, U,. Therefore, the rotational resistance of the cutter blade 50 becomes a loss of driving energy of the cutter blade 50. Moreover, local abrasion or erosion may occur on the surface 40 m of the cutter blade 50 or the extrusion nozzle 40 due to cavitation.

  Accordingly, an object of the present invention is to provide a cutter blade of a pellet manufacturing apparatus in which the contact surface of the cutter blade in contact with the surface of the extrusion nozzle, the surface of the extrusion nozzle in contact with the cutter blade, or both of these surfaces are less worn. . Another object of the present invention is to provide a cutter blade for a pellet manufacturing apparatus in which the vortex generated at the downstream end of the cutter blade is small or small. Furthermore, another object of the present invention is to provide a pellet manufacturing apparatus provided with a cutter blade that achieves the above-mentioned purpose.

  The cutter blade of the pellet manufacturing apparatus according to the present invention includes a mounting portion that is attached to the cutter holder in the same manner as a conventional cutter blade, and a blade that cuts molten resin extruded in a strand shape into cooling water in contact with the surface of a die or an extrusion nozzle It consists of parts. The blade portion includes a bottom surface on the back side that is driven to rotate close to the surface of the extrusion nozzle, a top surface on the front side that is substantially parallel to the bottom surface and spaced from the bottom surface by a predetermined height, and a predetermined position on the top surface. The rake face is tapered toward the tip end in the rotational direction, and the rake face is formed at the tip end of the rake face. The bottom surface is composed of a contact surface of a predetermined area that is driven to rotate in close proximity to or in contact with the surface of the extrusion nozzle, and a concave relief surface that is rearward of the contact surface, that is, in the advancing direction. In the cutter blade according to the present invention, in order to achieve the object of the present invention, a water passage hole reaching the concave flank is formed on the rake face. The extruder is configured substantially in the same manner as a conventional extruder from a cylinder barrel containing at least one screw and a die or an extrusion nozzle attached to the tip of the cylinder barrel.

  Thus, in order to achieve the above object, the invention according to claim 1 is provided with a mounting portion attached to the cutter holder, and a molten resin that moves on the surface of the extrusion nozzle and is extruded from the extrusion nozzle into the cooling water in a strand shape. And a blade portion that cuts in the cooling water, the blade portion being rotated in proximity to the surface of the extrusion nozzle and a back surface that is substantially parallel to the bottom surface and spaced apart from the bottom surface by a predetermined height. It is composed of a top surface on the front side, a rake face that is tapered and thinned toward the tip portion in a rotational direction from a predetermined position of the top surface, and a blade edge of the tip portion of the rake face, and the bottom surface is A cutter blade comprising a contact surface of a predetermined area that is rotationally driven in contact with the surface of the extrusion nozzle, and a concave flank surface that is rearward of the contact surface in the direction of travel. Hole is said concave Of the flank exit holes of the cooling water is formed, the inlet holes and outlet holes are configured to communicate with the water passage hole.

  The invention according to claim 2 is the cutter blade according to claim 1, wherein a plurality of the inlet holes and the outlet holes are formed, and these holes communicate with each other through the water passage holes. In the cutter blade according to claim 1 or 2, in the cutter blade according to claim 1 or 2, the inlet hole is positioned in front of the outlet hole when viewed in the rotation or traveling direction, whereby the water passage hole cuts cooling water. In the cutter blade according to any one of claims 1 to 3, the cutter blade according to any one of claims 1 to 3 may be inclined so as to be easily guided to the back side of the blade. The notch-shaped enlarged diameter portion is formed.

  The invention according to claim 5 is a cylinder barrel provided with at least one screw for transferring the thermoplastic resin in the axial direction, an extrusion nozzle provided in a discharge part of the cylinder barrel, A manufacturing apparatus for obtaining pellets by cutting the molten resin extruded in a strand form into cooling water from the extrusion nozzle in the cooling water by the cutter apparatus in the cooling water. The cutter device is a plurality of cutters attached to a circumferential portion of a cutter holder that is pressed to the extrusion nozzle side with a predetermined force and is driven at a predetermined rotational speed at predetermined intervals in the circumferential direction. The cutter blade comprises an attachment portion attached to the cutter holder, and a blade portion that moves on the surface of the extrusion nozzle. A bottom surface on the back side that is driven to rotate close to the surface of the slip, a top surface on the front side that is substantially parallel to the bottom surface and spaced from the bottom surface by a predetermined height, and a tip when viewed from the predetermined position of the top surface in the rotation direction A rake face that is tapered toward the part and a cutting edge at the tip of the rake face, and the bottom face is in contact with the surface of the extrusion nozzle and has a contact area with a predetermined area, It consists of a concave flank that is rearward of the contact surface in the direction of travel, and an inlet hole for cooling water is formed on the rake face, and an outlet hole for cooling water is formed on the concave flank. The outlet hole is configured to communicate with the water passage hole, and the invention according to claim 6 is the apparatus according to claim 5, wherein at least part of the periphery of the inlet hole has a notch-shaped enlarged diameter portion. Is formed.

  As described above, according to the present invention, the cooling water inlet hole is formed in the front rake face of the cutter blade, and the outlet hole is formed in the concave concave flank face, and these holes communicate with the water passage hole. Therefore, a part of the cooling water flowing along the rake face of the cutter blade flows through the gap between the flank face of the cutter blade and the surface of the extrusion nozzle through the water passage hole. That is, the flow rate of the cooling water along the rake face decreases, and the downward reaction force that pushes down the cutter blade decreases. Further, since the pressure flows through the gap, an upward force is generated on the cutter blade. As a result, it is possible to prevent the cutter blade and / or the surface of the extrusion nozzle from being worn due to an excessive downward reaction force. Further, when the entire amount of cooling water flows along the rake face, a large amount of vortex is generated at the rear end portion of the cutter blade. According to the present invention, a part of the cooling water is separated from the flank face of the cutter blade and the extrusion nozzle. Since it flows through the gap with the surface, the amount of vortex generation is small, and the energy for rotationally driving the cutter blade is small. Furthermore, since the vortex is reduced, it is hydraulically stable and local wear or erosion due to mechanical vibration and cavitation is also reduced. According to another invention, since a plurality of cooling water inlet holes are provided, or because a notch-shaped enlarged portion is formed around a part of the inlet hole, the number of cooling water inlet holes, Change the shape and size of the notch as appropriate along with the size, etc., and adjust the downward force to press the cutter blade against the surface of the extrusion nozzle and the upward force to release it regardless of the rotation speed of the cutter blade. Thus, the wear of the cutter blade and / or the surface of the extrusion nozzle can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows a part of pellet manufacturing apparatus which concerns on embodiment of this invention, The (a) is the front view, The (a) is a perspective view of a cutter blade, The (c) is an arrow view in (a). Sectional drawing equivalent to the figure seen in the Wu direction, The (d) is a side view which shows the attachment state of a cutter blade. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows embodiment of this invention, The (a) is a perspective view which expands partially and shows the state in which the cutter blade is attached in contact with the surface of an extrusion nozzle, The (a) explains an effect | action. It is sectional drawing of the principal part for doing. It is a figure which shows the cutter blade which concerns on other embodiment of this invention, The (a) is the top view, The (a) is sectional drawing seen in the arrow direction easy direction in (a). It is a figure which shows the cutter blade which concerns on other embodiment of this invention, The (a) is the top view, The (a) is sectional drawing seen in the arrow direction easy direction in (a). It is a figure which shows the principal part of the conventional pellet manufacturing apparatus, The (a) is a perspective view which shows the state in which the cutter blade is attached in contact with the surface of an extrusion nozzle, The (a) is the key for explaining an effect | action. It is sectional drawing of a part.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. The pellet manufacturing apparatus according to the present embodiment is roughly composed of an extruder 1 and a cutter apparatus 10 as in the conventional manufacturing apparatus. The extruder 1 is not shown in its entirety in the figure, but includes a cylinder barrel 2 having a predetermined length in the axial direction. A band heater is provided on the outer periphery of the cylinder barrel 2, and at least one is provided inside. The screw is provided so as to be driven to rotate. On the upstream side of the cylinder barrel 2, a hopper for temporarily storing a molding material or an extrusion material is provided, and the downstream end of the cylinder barrel 2 or the end of the discharge chamber 3 is shown in FIG. As shown, the die 4 is attached so as to partition the discharge chamber 3. The die 4 has a substantially disc shape, but a ring-shaped extrusion nozzle 5 is formed on the opposite surface of the discharge chamber 3. Alternatively, a ring-shaped extrusion nozzle 5 is attached to the back side of the die 4. The cross-sectional shape of the extrusion nozzle 5 has a substantially trapezoidal shape, and a plurality of nozzle holes 7, 7,. These nozzle holes 7, 7,... Communicate with the discharge chamber 3 of the cylinder barrel 2 through communication holes 8, 8,. A plurality of cutter blades 20, 20,... Described later are rotated in proximity to or in contact with the top surface 6 of the extrusion nozzle 5 thus configured.

  As shown in FIG. 1A, the cutter device 10 includes a housing 11, a cutter shaft 12 rotatably provided in the housing 11, a cutter holder 13 fixed to the tip of the cutter shaft 12, It comprises a plurality of cutter blades 20, 20,... Attached to the cutter holder 13. The cutter holder 13 has a substantially conical shape as a whole. That is, it is composed of a large-diameter mounting surface portion facing the die 4 side and a small-diameter boss portion 14 on the opposite side. A relief having a predetermined depth is formed inside the mounting surface portion, and a through hole 15 reaching the relief in the axial direction is formed in the boss portion 14. The cutter holder 13 is attached to the cutter shaft 12 using this through hole 15. In addition, a plurality of sets of female screws with a predetermined depth for mounting the cutter blade, each of which is a set of two, are formed on the mounting surface portion of the cutter holder 13 at equal intervals.

  The cutter holder 13 configured in this manner is rotationally driven while being pressed by the cutter shaft 12 in the direction of the die 4 with a predetermined force, but the driving motor and the like are shown in the figure. It has not been.

  As shown in the perspective view of FIG. 1A and the sectional view of FIG. 1C, the cutter blade 20 has a substantially rectangular parallelepiped shape and has a blade portion 20a having a constant thickness “h” in the length direction. And an attachment portion 20b attached to the cutter holder 13. The front side of the blade portion 20a is composed of a top surface 20c and an inclined surface that is inclined so as to become thinner from the top surface 20c toward the tip portion in the rotational direction, that is, a rake surface 20d. The cutting edge 20e is formed. The bottom surface on the back side is composed of a contact surface 20g having a predetermined width that is driven to rotate in contact with the surface 6 of the extrusion nozzle 5, and a concave relief surface 20h that is rearward with respect to the traveling direction of the contact surface 20g. Yes. As shown in FIG. 2A, molten resin 7s, 7s,... Is extruded into a strand shape from the nozzle holes 7, 7,. It is permissible to grow. Two through holes 20i, 20i for inserting bolts are opened in the mounting portion 20b.

  In the rake face 20d of the cutter blade 20 configured in this way, as shown in FIGS. 1A and 1C, in the present embodiment, two cooling water inlet holes 21, 21 are provided. Is formed. Similarly, two outlet holes 22 and 22 for cooling water are formed on the flank 20h. These holes 21, 22,... Are communicated with each other through water holes 23, 23. In the embodiment shown in FIGS. 1A and 1C, the inlet holes 21, 21 and the outlet holes 22, 22 and the water passage holes 23, 23 have the same diameter, and the inlet holes 21, 21 are outlets. The cutter blade 20 is positioned forward of the holes 22 and 22 in the rotational direction or the traveling direction of the cutter blade 20. As a result, as shown in FIG. 1C, the water passage holes 23 and 23 are inclined from the outside to the inside so that the cooling water can easily enter when the cutter blade 20 is driven to rotate. ing.

  The plurality of cutter blades 20, 20,... Configured as described above are detachably attached radially to the attachment surface portion of the cutter holder 13 by bolts (not shown). The state where the cutter blades 20, 20,... Are attached is shown in the side view of FIG. The cutter blades 20, 20,... Attached in this way together with the die 4, the extrusion nozzle 5 and the like are, as shown in FIG. 1A, a cooling water supply port 30a and a cooling water discharge port. And a cutter case 30 provided with 30b. Therefore, when the cooling water is injected from the cooling water supply port 30a, the inside of the cutter case 30 is filled with the cooling water, and the die 4, the extrusion nozzle 5, the cutter blades 20, 20,.

  Next, the example which manufactures a pellet by the said embodiment is demonstrated. While the cooling water is supplied from the cooling water supply port 30a and discharged from the cooling water discharge port 30b, the screw of the extruder 1 is rotationally driven. The extrusion material continuously supplied from the hopper is melted as is conventionally known in the process of being transferred through the cylinder barrel 2, and a plurality of nozzle holes 7, 7,... Are continuously extruded into the cutter case 30 in a strand shape. At this time, when the cutter shaft 12 is driven at a predetermined rotational speed while pressing the cutter shaft 12 in the direction of the die 4 with a predetermined force by a driving device not shown in the drawing, the cutter blades 20, 20,. Are driven to rotate in a state where they contact the surface 6 of the extrusion nozzle 5. Therefore, the molten resins 7s, 7s,... Extruded continuously in a strand shape are cut in cooling water by the cutter blades 20, 20,... Into pellets having a predetermined size and a predetermined length. A state in which the contact surfaces 20g, 20g,... Are rotationally driven while being in contact with the surface 6 of the extrusion nozzle 5 is shown in the enlarged perspective view of FIG. This is shown in the enlarged sectional view of FIG. The pellets cut to a predetermined length are discharged together with the cooling water from the cooling water discharge port 30b, separated from the cooling water and dried.

  When the pellets are obtained as described above, according to the conventional cutter blade 50, as described above, if the flow rate per unit time is Qa with respect to the unit length in the direction perpendicular to the drawing, the cooling water The downward reaction force Pa which tries to press the cutter blade 50 against the surface of the extrusion nozzle 40 is generated on the rake face 50k of the cutter blade 50 by the change in momentum (Qa) · (v1-v2) caused by the change in the flow of the nozzle. However, according to the present embodiment, the rake face 20d of the cutter blade 20 and the flank 20h communicate with each other through the water holes 23, 23. Therefore, the streamline generated on the rake face 20d of the cutter blade 20 is As shown in FIG. 2A, the flow line is divided into a streamline rA along the rake face 20d and a streamline rB flowing through the water holes 23 and 23. The flow rate Qa of the cooling water along the rake face 20d is reduced by the amount of the divided flow, and the downward reaction force Pa that pushes down the cutter blade 20 is reduced. Further, the diverted cooling water flows through a gap between the flank 20h of the cutter blade 20 and the surface 6 of the extrusion nozzle 5, so that a downward reaction force Pa is applied to the cutter blade 20 by the pressure at this time. An upward force Pb to erase is generated. This prevents wear of the cutter blade 20 and / or the surface 6 of the extrusion nozzle 4 due to an excessive downward reaction force Pa.

  Furthermore, when the entire amount of cooling water flows along the rake face 50k as in the prior art, a large amount of vortices U, U,... Are generated at the rear end of the cutter blade 50. According to this embodiment, the cooling water Are separated and merged at the rear end portion through the gap between the flank 20h of the cutter blade 20 and the surface 6 of the extrusion nozzle 5, so that the amount of vortex generated is small. Thereby, the energy for rotationally driving the cutter blade 20 can be reduced. In addition, pressure fluctuations occur due to the generation of vortices, but according to this embodiment, the amount of vortex generation is reduced or the vortices become smaller, so that it is hydraulically stable and local wear due to mechanical vibration and cavitation. Or erosion is reduced. Further, since the vortex becomes small, the cut pellets are smoothly discharged from the cooling water discharge port 30b.

  According to the above embodiment, the cooling water inlet holes 21 and 21, the water flow holes 23 and 23, and the cooling water outlet holes 22 and 22 are formed to have the same diameter, but the number, shape, etc. The present invention is not limited to the above-described embodiment, and it is obvious that the cutter blade 20 can be deformed according to the number of blades, shape, rotation speed, and the like. 3 and 4 show an embodiment in which enlarged diameter portions having different shapes are formed around the inlet holes 21 and 21 of the cooling water. That is, the same reference numerals are assigned to the same elements as those of the above-described embodiment, and the description is not repeated. However, according to the embodiment shown in FIG. A rectangular notch 21a having a predetermined depth is formed in the upper portion. By this notch 21a, the cooling water flowing along the rake face 20d of the cutter blade 20 is blocked against the vertical wall of the notch 21a, so that the pressure rises and the amount of cooling water flowing through the water holes 23, 23 is reduced. Increase. Thereby, the said force Pb which separates the flank 20h of the cutter blade 20 from the surface 6 of the extrusion nozzle 5 increases. The shape and size of the notch 21a are appropriately changed together with the number and size of the cooling water inlet holes 21, so that the cutter blade 20 can be used as an extrusion nozzle regardless of the rotational speed of the cutter blades 20, 20,. By adjusting the downward force Pa pressed against the surface 6 of the surface 5 and the upward force Pb released, it is possible to prevent the cutter blade 20 and / or the surface 6 of the extrusion nozzle 5 from being worn. FIG. 4 shows an embodiment in which the notch 21 b is formed around the inlet hole 21. Obviously, similar effects can be obtained.

DESCRIPTION OF SYMBOLS 1 Extruder 3 Discharge chamber 4 Dies 5 Extrusion nozzle 7 Nozzle hole
DESCRIPTION OF SYMBOLS 10 Cutter apparatus 12 Cutter shaft 13 Cutter holder 20 Cutter blade 20a Blade part 20b Mounting part 20d Rake face 20g Contact surface 20h Flank
21 Cooling water inlet hole 21a Notch (expanded part)
21b Notched portion (expanded diameter portion) 22 Cooling water outlet hole 23 Water passage hole 30 Cutter case 30a Cooling water supply port 30b Cooling water discharge port

Claims (6)

An attachment part attached to the cutter holder, and a blade part that moves on the surface of the extrusion nozzle and cuts the molten resin extruded in a strand shape from the extrusion nozzle into the cooling water in the cooling water,
The blade portion includes a bottom surface on the back side that is driven to rotate close to the surface of the extrusion nozzle, a top surface on the front side that is substantially parallel to the bottom surface and spaced from the bottom surface by a predetermined height, and a predetermined position on the top surface. The rake face is tapered toward the tip when viewed from the direction of rotation, and the cutting edge of the tip of the rake face,
The bottom surface is a cutter blade composed of a contact surface of a predetermined area that is rotationally driven in contact with the surface of the extrusion nozzle, and a concave relief surface that is rearward as viewed in the direction of travel from the contact surface,
A cooling water inlet hole is formed in the rake face, a cooling water outlet hole is formed in the concave flank face, and the inlet hole and the outlet hole communicate with each other through a water passage hole. Cutter blade for manufacturing equipment. The cutter blade according to claim 1, wherein a plurality of the inlet holes and the outlet holes are formed, and these holes communicate with each other through the water passage holes. 3. The cutter blade according to claim 1, wherein the inlet hole is positioned in front of the outlet hole when viewed in the rotation or traveling direction, whereby the water passage hole easily guides cooling water to the back side of the cutter blade. The cutter blade of the pellet manufacturing apparatus is inclined like this. The cutter blade according to any one of claims 1 to 3, wherein a notch-shaped enlarged portion is formed in a part of the periphery of the inlet hole. A cylinder barrel provided with at least one screw for transferring the thermoplastic resin in the axial direction, an extrusion nozzle provided in a discharge portion of the cylinder barrel, and provided corresponding to the extrusion nozzle; A manufacturing apparatus that obtains pellets by cutting the molten resin extruded in a strand form into the cooling water from the extrusion nozzle in the cooling water by the cutter apparatus in the cooling water,
The cutter device is a plurality of cutters attached to a circumferential portion of a cutter holder that is pressed to the extrusion nozzle side with a predetermined force and is driven at a predetermined rotational speed at predetermined intervals in the circumferential direction. Consisting of a blade,
The cutter blade is composed of an attachment portion attached to the cutter holder and a blade portion that moves on the surface of the extrusion nozzle.
The blade portion includes a bottom surface on the back side that is driven to rotate close to the surface of the extrusion nozzle, a top surface on the front side that is substantially parallel to the bottom surface and spaced from the bottom surface by a predetermined height, and a predetermined position on the top surface. The rake face is tapered toward the tip when viewed from the direction of rotation, and the cutting edge of the tip of the rake face,
The bottom surface includes a contact surface having a predetermined area that is rotationally driven in contact with the surface of the extrusion nozzle, and a concave relief surface that is rearward as viewed in the traveling direction from the contact surface, and the rake surface has an inlet hole for cooling water. However, a cooling water outlet hole is formed in the concave flank, and the inlet hole and the outlet hole communicate with each other through a water passage hole. 6. The pellet manufacturing apparatus according to claim 5, wherein a notch-shaped enlarged diameter portion is formed at least at a part around the inlet hole.