JP2005059528A - Rotor for kneading - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To curtail a time necessary for kneading by improving cooling efficiency in relation to a material to be kneaded such as a rubber. <P>SOLUTION: In a rotor for kneading, rotary shafts 51 and 71 and rotor bodies 52 and 72 which are engaged/fixed with/to the peripheries of the rotary shafts 51 and 71, have blade parts for kneading on the outside surfaces, and arrange/form disk-like channel parts 57a and 77a expanding toward the outside surfaces in the axial directions of the shafts 51 and 71 on the inside surfaces contacting the rotary shafts 51 and 71 are provided, and a cooling medium is passed through each disk-like channel part 57a or 77a. Cores 58 and 78 facing the corresponding disk-like channel parts 57a and 77a from the peripheries of the rotary shafts 51 and 71 are arranged in each disk-like channel parts 57a or 77a. The depth of the disk-like channel parts 57a and 77a is reduced practically by the cores 58 and 78. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a kneading rotor applied to a kneading machine such as a kneading machine or a kneading extruder.

  FIG. 12 is a longitudinal sectional view showing a conventional closed kneader. As shown in the figure, a kneading chamber 101 is formed in the casing 100, and a pair of rotors 102 and 103 are arranged in parallel in the kneading chamber 101. The rotor 102 (103) has a configuration in which the rotor body 102b (103b) is fitted and fixed to the outer periphery of the rotating shaft 102a (103a).

  The kneaded material charged through the hopper 104 is press-fitted into the kneading chamber 2 by the floating weight 105, and then meshes with the rotor main bodies 102b and 103b rotating in opposite directions, and the rotor main bodies 102b and 103b and the kneading chamber. They are kneaded by the shearing action that occurs between the inner surface of 101. The kneaded material is taken out of the kneading chamber 101 by opening a drop door 106 provided at the bottom of the kneading chamber 101.

By the way, generally, when kneading a kneading material such as rubber, a large amount of heat is generated. Therefore, the rotor main bodies 102b and 103b are cooled by circulating a cooling medium such as water therein. Jackets 102c and 103c provided on the rotary shafts 102a and 103a are for supplying and discharging the cooling medium. (For example, Patent Document 1)
JP 2001-150428 A

However, the conventional kneading rotors 102 and 103 are not good in cooling efficiency of the outer surface portion in contact with the kneaded material due to the structure of the passage through which the cooling medium passes, and therefore have a cooling capacity for the kneaded material. It has the problem of being low.
Therefore, in the current kneading operation, the temperature of the kneaded material being kneaded is monitored, and when the temperature rises to a predetermined temperature (for example, about 150 ° C. for rubber) before the kneaded material is deteriorated, the kneading machine Then, the operation of discharging from the kneaded material, cooling the material, and charging it again into the kneader is repeated an appropriate number of times.
Such re-milling (re-milling) work takes a lot of time, and thus becomes a factor of reducing the productivity of products such as tires. For this reason, a kneading rotor having a high cooling capacity for the kneaded material is desired.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a kneading rotor capable of improving the cooling efficiency for kneading materials such as rubber and shortening the time required for kneading. Yes.

  The present invention has been made to solve such a problem, and is a kneading rotor having a rotating shaft and a rotor body fitted and fixed to the outer periphery of the rotating shaft. A plurality of disk-shaped grooves extending from the inner peripheral surface in contact with the rotating shaft toward the outer surface are formed in the axial direction of the shaft, and kneading blades are formed on the surface. A cooling medium is arranged in each disk-shaped groove, and a core extending from the inner peripheral surface of the front rotor body toward the outer surface is disposed in each disk-shaped groove, and the depth of the disk-shaped groove is increased by the core. It is characterized by substantially reducing the thickness.

The kneading rotor according to the present invention is suitable for use in a kneading rotor of a batch type kneader or a biaxial or uniaxial kneading extruder.
The kneading rotor applied to the kneading extruder can include at least one long blade portion as the kneading blade portion. In this case, the twist angle of the long blade portion with respect to the axis of the shaft is 35. It is desirable to set the angle to 55 °.
A kneading rotor applied to the kneading extruder includes a first wing portion that is a long wing portion, a second wing portion that is a short wing portion, and a third wing portion as the wing portions for kneading. In this case, the twist angle of the first wing portion with respect to the axis of the shaft and the twist angle of at least one of the second wing portion and the third wing portion with respect to the axis are set to 35 ° to 55 °. Is desirable.

  According to the kneading rotor according to the present invention, the core is disposed in each disk-shaped groove provided in the rotor body, and the depth of the disk-shaped groove is substantially reduced by the core. Therefore, it is possible to increase the cooling medium flow rate in the vicinity of the inner peripheral surface (bottom) of each disk-shaped groove, that is, in the portion close to the outer surface of the rotor body, and to improve the cooling efficiency at that portion. Therefore, it is most suitable as a kneading rotor for use in a batch-type kneader or a biaxial or uniaxial kneading extruder.

FIG. 1 is a longitudinal sectional view showing a batch type kneader M to which a kneading rotor according to the present invention is applied. In the kneading machine M, a pair of kneading rotors 5 and 7 are disposed in a kneading chamber 3 formed in the casing 1. As shown in FIG. 2, the rotors 5 and 7 are arranged in parallel, and are rotated at a constant speed in opposite directions by driving means (not shown).
The kneading rotors 5 and 7 have the same or similar configuration. Therefore, in the following, the configuration and operation of the rotor 5 will be mainly described. In FIG. 3, the reference numerals of the components of the rotor 7 are shown in parentheses.

The kneading rotor 5 is composed of a rotating shaft 51 and a rotor body 52 fitted and fixed to the outer periphery of the shaft 51 by means such as shrink fitting as shown in FIG. Yes.
The rotating shaft 51 includes passages 53 to 56 for circulating a cooling medium such as water. The passage 53 is formed along the axis of the rotary shaft 51, and its tip is closed. The passage 54 is formed coaxially in the passage 53, and its tip is open near the tip of the passage 53. On the other hand, the passage 55 and the passage 56 are extended from the passage 53 toward one end and the other end of the rotor body 52.

The rotor main body 52 and the rotor main body 72 have a plurality of blade portions 59a, 59b,... And blade portions 79a, 79b,. 79b... Mesh with each other. The outer surface of the rotor body 52 is subjected to treatment such as Cr plating in order to improve wear resistance and corrosion resistance. In addition, you may perform processes, such as Cr plating, after building up stellite.
On the other hand, the rotor body 52 is formed with a series of grooves 57 for passing the cooling medium on the inner peripheral surface thereof in contact with the peripheral surface of the shaft 51, and one end and the other end of the groove 57 are formed in the passages 55 and 56, respectively. Communicated.

  The groove 57 is formed in a spiral shape by connecting a large number of disk-shaped groove portions 57 a arranged in parallel in the longitudinal direction of the rotor body 52. The depth of each disk-shaped groove 57 a is set so as to extend to a portion close to the outer surface of the rotor body 52. Therefore, in the disk-shaped groove 57a, the depth of the portion located on the blade forming side of the rotor body 52 is larger than the depth of the portion located on the blade non-forming side. Note that the inner peripheral surface of each disk-shaped groove 57 a constitutes the bottom of the groove 57.

  FIG. 1 shows a distance d between the inner peripheral surface of the disk-shaped groove 57a and the outer surface of the rotor body 52. This distance d is preferably as small as possible in order to reduce the thermal resistance of the rotor body 52, in other words, in improving the heat transfer coefficient of the rotor body 52. However, this distance d cannot be reduced unnecessarily from the viewpoint of the strength of the rotor body 52 and the processing of the groove 57.

A core 58 is inserted into the disk-shaped groove 57a. The core 58 is fixed in the disk-shaped groove 57a by means such as fitting or metal joining (welding, etc.), and its outer end surface is in contact with the peripheral surface of the shaft. The groove 57a is formed so as to face the inner peripheral surface of a portion having a large depth.
The core 58 has a space with a narrow cross-sectional area in the vicinity of the inner peripheral surface, that is, the peripheral surface of the shaft 51 and the inner peripheral surface of the portion having a large depth of the disk-shaped groove portion 57a. A space having a cross-sectional area that is not significantly different from the cross-sectional area of the space formed by the inner peripheral surface of the portion having a small depth of the disk-shaped groove 57a is formed. Thus, the core 58 functions as means for substantially reducing the depth of the disk-shaped groove 57a.

Next, the operation of the kneading rotors 5 and 7 will be described.
The materials to be kneaded, such as raw rubber and compounding agents (carbon black, silica, oil, chemicals, etc.) charged into the kneading chamber 3 of the kneading machine M shown in FIG. The kneading is performed by the mutual meshing action 72 and the shearing action generated between the rotor bodies 52 and 72 and the inner surface of the kneading chamber 3.

During kneading, a pressurized cooling medium such as water is circulated through the cooling passage 9 (see FIG. 1) provided in the casing 1, and the same cooling medium is fed into the passage 54 shown in FIG.
The cooling medium fed into the passages 54 flows into the passages 53, and then flows through the passages 55 into one end of the groove 57 of the rotor body 52. The cooling medium flowing into the grooves 57 sequentially passes through the respective disk-shaped groove portions 57a. At this time, in a portion having a large depth in the disk-shaped groove 57a, the cooling medium flows through a narrow cross-sectional area passage sandwiched between the inner peripheral surface of the disk-shaped groove 57a and the outer peripheral surface of the core 58. The surface layer portion of the rotor main body 5 is efficiently cooled even at the portion where the depth is large.

  That is, if the core 58 is not present, the medium passage cross-sectional area of the portion having a large depth in the disk-shaped groove portion 57a becomes large, so that the flow velocity of the cooling medium at that portion is lower than that of the other portions. Become. However, according to the kneading rotor 5 provided with the core 58, the cooling medium can be circulated at high speed in the vicinity of the inner peripheral surface of the disk-shaped groove portion 57a even at a large depth portion. The cooling efficiency of the surface layer portion of the rotor main body 5 at the large portion, that is, the blade portion that needs the most cooling is improved.

Also in the other kneading rotor 7 provided with the core 78, the flow rate of the cooling medium in the portion having a large depth in the disk-shaped groove 77a can be increased, so that the cooling efficiency of the surface layer portion of the rotor body 7 in this portion is increased. Will improve.
Thus, according to the kneading machine M to which the kneading rotors 5 and 7 are applied, it is possible to improve the cooling capacity for rubber and knead at a low temperature.

FIG. 4 is an internal plan view schematically showing an example of a twin-screw kneading extruder to which the kneading rotor according to the present invention is applied.
This biaxial kneading extruder MP has a pair of rotating shafts 11 and 11 in parallel. Each rotary shaft 11 has an extrusion rotor 15 at one end together with the screw fins 13, a rotor 19 for kneading together with the rotor main body 17, and an extrusion rotor 23 along with the screw fins 21 provided around the other end. It is composed.

  The kneading rotor 19 has the same configuration as that of the kneading rotors 5 and 7 except that the configuration of the outer surface of the rotor body 17 is different from that of the kneading rotors 5 and 7 shown in FIG. That is, although not shown, the rotor main body 17 of the rotor 19 includes a cooling groove corresponding to the groove 57 (77) including the plurality of disk-shaped groove portions 57a (77a) shown in FIG. 2 and the core shown in FIG. 58 (78) is provided. Further, the shaft 11 is provided with passages (not shown) corresponding to the passages 53 to 56 (73 to 76) shown in FIG.

As shown in FIG. 5, the rotor body 17 includes a first wing portion 171 that is a long wing portion disposed in the center portion, and a second wing portion that is a short wing portion disposed on both sides of the first wing portion 171. Part 172 and third wing part 173.
As shown in FIG. 6, which is a developed view of the rotor body 17, the first blade 171 has a twist angle θ1 with respect to the axis of the shaft 11 (not shown in FIGS. 5 and 6) of 35 ° to 55 °. The axial distance from the left end in the figure to the left end of the rotor body 17 is set to be equal to the axial distance from the right end to the right end of the rotor body 17. On the other hand, the second wing portion 172 and the third wing portion 173 are such that the former starting point is located at the left end of the rotor body 17 and the latter starting point is located at the right end of the rotor body 17, respectively. Are provided so as to have a predetermined angle with respect to the axis.

  The pair of opposed rotor bodies 17 are arranged with a phase difference of 180 ° from each other, and when rotating, the first wing part 171 of one rotor body 17 is connected to the second wing part 172 and the third wing part 172 of the other rotor body 17. It passes between the wings 173 while engaging with them. Note that an arrow 174 in the figure indicates the rotation direction of the rotor body 17.

  In the twin-screw kneading extruder MP shown in FIG. 4, the opposing extrusion rotor 15 conveys the material to be kneaded introduced from a hopper (not shown) in the downstream direction and supplies it to the opposing kneading rotor 19. Each kneading rotor 19 kneads the material to be kneaded by the meshing of the wing portions 171 to 173 shown in FIGS. 5 and 6 and by the shearing force generated between the wing portions 171 to 173 and the casing 25. Then, the kneaded material is carried out to the next step by the respective extrusion rotors 23 located on the downstream side of the respective kneading rotors 19.

  As described above, each kneading rotor 19 has a configuration similar to that of each kneading rotor 2 shown in FIG. 1, and therefore exhibits extremely high cooling capacity for the material to be kneaded. Further, each kneading rotor 19 has the twist angle θ1 of the first blade portion 171 shown in FIG. 6 set to 35 ° to 55 °, so that the temperature rise of the material to be kneaded can be further suppressed. The reason will be described below.

FIG. 7 is a graph showing experimental results for confirming the axial fluidity. In this graph, the horizontal axis represents the twist angle θ1 of the first wing portion 171 and the vertical axis represents the axial pressure gradient.
As is apparent from this graph, the maximum pressure gradient is obtained when the twist angle θ1 is 45 °, and the axial flow of the material to be kneaded is the best, and the mixing and dispersibility of the compounding agent is the best. Become. When the twist angle θ1 is 35 ° to 55 °, good axial fluidity is ensured while maintaining the necessary shearing force. If such good axial fluidity is ensured, the temperature rise of the material to be kneaded will be suppressed.

  The twist angle of at least one of the second wing portion 172 and the third wing portion 173 may be set to 35 ° to 55 ° similarly to the twist angle θ1 of the first wing portion 171. FIG. 8 is a graph showing experimental results for confirming the action when the twist angle θ2 of the second wing portion 172 is set to 35 ° to 55 °, which is the same as the twist angle θ1 of the first wing portion 171. In this experiment, an extrusion kneader simulating an actual machine was filled with a CMC (carboxyl-methyl-cellulose) aqueous solution, while colored glass beads were added as a material to be kneaded, and the degree of mixing was measured.

  In this graph, the horizontal axis represents the twist angles θ1 and θ1, and the vertical axis represents the accumulated rotational speed required for uniform mixing. A smaller integrated rotation number means that kneading is completed in a shorter time. Referring to FIG. 8, it can be seen that the twist angles θ1 and θ2 are small at a value in the vicinity of 45.0 °. In this case, the rotor volume is slightly reduced and the kneading volume is increased. Therefore, by setting the twist angles θ1 and θ2 of the first blade portion 171 and the second blade portion 172 to 35 ° to 55 °, the volume efficiency and the void volume are increased. This is the production of the twin-screw kneading extruder. Improvement in weight and kneadability and reduction in weight. Of course, the twist angle of the third wing part 173 may be made to coincide with the twist angle θ1 of the first wing part 171, and the twist angles of both the second wing part 172 and the third wing part 173 may be set. The twist angle θ1 of 171 may be the same.

  In the above description, the case where there is one long wing portion and two short wing portions has been described, but the number of wing portions is not limited to this. For example, only one or more long wings may be provided, or two or more long wings and three or more short wings may be provided.

FIG. 9 is an internal plan view schematically showing an example of a single-screw kneading extruder to which the kneading rotor according to the present invention is applied. The uniaxial kneading extruder MP ′ and the biaxial kneading extruder MP shown in FIG. 4 are the same except that the number of shafts and the width of the former casing 25 ′ are set narrower than the width of the latter casing 25. It has a configuration. Therefore, a common code is given to the elements corresponding to both.
The kneading rotor 19 of the uniaxial kneading extruder MP ′ kneads the material to be kneaded by a shearing force generated between the blade portion of the rotor body and the inner surface of the casing 25 ′.

  FIG. 10 shows a kneading system in which the batch kneader M shown in FIG. 1 is applied to both master kneading and final kneading. In this kneading system, first, the raw rubber and the compounding agent are kneaded (master kneading) using the kneader M1. The kneading machine M1 has excellent cooling capacity for the kneaded material due to the action of the cores 58 and 78 shown in FIG. 1, so that re-kneading (remill) operation as in the conventional kneading machine becomes unnecessary, or re-kneading. The number of times can be reduced.

In the kneader M1, the material to be kneaded is discharged when the BIT (Black carbon incorporate time) at which the dispersion of the rubber and the compounding agent is almost finished is reached. The discharged material to be kneaded is cooled and formed into a sheet by the undermixer 29, and is then added to the kneading machine M2 together with the vulcanizing agent and kneaded (final kneading). After the final kneading, the rubber material taken out from the kneader M2 is cooled and formed into a sheet by the undermixer 31, and used as a material for rubber products such as tires.
As described above, according to this manufacturing system, the re-kneading operation becomes unnecessary or the number of times of re-kneading decreases, so that the time required for the kneading work can be shortened and the productivity can be improved.

FIG. 11 shows a kneading in which the batch kneader M shown in FIG. 1 is applied to the master kneading, and the biaxial kneading extruder MP ′ shown in FIG. 4 or the uniaxial kneading extruder MP ′ shown in FIG. 9 is applied to the final kneading. 2 shows another example of the system.
This kneading system is common to the above system in the process of performing master kneading with the kneader M and cooling and sheeting the material after the master kneading with the undermixer 29. The rubber material formed into a sheet by the undermixer 29 is put into a twin-screw kneading extruder MP together with a vulcanizing agent and subjected to extrusion, kneading (final kneading), cooling, and extrusion treatment, and then formed into a sheet. It will be.
In the biaxial kneading extruder MP or the uniaxial kneading extruder MP ′, the kneading rotor 19 shown in FIGS. 4 and 9 has a cooling function similar to that of the kneading rotors 5 and 7 of the kneader M (see FIG. 1). Therefore, in this system, the final kneading can be continuously executed by the biaxial kneading extruder MP or the uniaxial kneading extruder MP ′ as described above to further improve the productivity.

FIG. 12 shows still another example of a rubber sheet manufacturing system in which the above-described biaxial kneading extruder MP or uniaxial kneading extruder MP ′ is used for both master kneading and final kneading.
In this system, first, a raw rubber and a compounding agent are continuously kneaded (master kneaded) and extruded by a biaxial kneading extruder MP1 or a uniaxial kneading extruder MP1 ′, and the master kneaded rubber material is vulcanized. At the same time, it is continuously kneaded (final kneaded) and extruded by the biaxial kneading extruder MP2 or the uniaxial kneading extruder MP2 ′. Thus, according to this system, since master training to final training is continuous, productivity is improved as compared with the system shown in FIG.

It is a longitudinal cross-sectional view which shows the principal part of the kneading machine to which the rotor for kneading | mixing which concerns on this invention was applied. It is the figure which illustrated the external appearance structure of the rotor for kneading | mixing shown in FIG. It is the figure which cut the rotor for kneading shown in Drawing 1 in the field containing the axis of a rotating shaft. 1 is an internal plan view of a twin-screw kneading extruder to which a kneading rotor according to the present invention is applied. It is the figure which illustrated the external appearance structure of the rotor for kneading | mixing shown in FIG. FIG. 5 is a development view of the rotor body of the kneading rotor shown in FIG. 4. It is a graph which shows the experimental result for confirming the axial fluidity | liquidity of the rotor for kneading | mixing shown in FIG. It is a graph which shows the experimental result for confirming an effect | action when the twist angle of the 2nd wing | blade part shown in FIG. 6 is set to 35 degrees-55 degrees same as the twist angle of a 1st wing | blade part. It is an internal top view of the single screw kneading extruder to which the rotor for kneading concerning the present invention was applied. It is the schematic which shows the structure of the kneading system which applied the batch type kneader to both master kneading and final kneading. It is the schematic which shows the structure of the kneading | mixing system which applied the batch type kneader to the master kneading, and applied the biaxial kneading extruder or the uniaxial kneading extruder to the final kneading. It is the schematic which shows the structure of the kneading | mixing system which used the biaxial kneading extruder or the uniaxial kneading extruder for both master kneading and final kneading. It is a longitudinal cross-sectional view which shows the structure of the conventional closed type (batch type) kneader.

Explanation of symbols

M, M1, M2 Batch type kneader 1 Casing 3 Kneading chamber 5, 7 Kneading rotor 51, 71 Rotating shaft 52, 72 Rotor body 53-56, 73-76 Passage 57, 77 Groove 57a, 77a Disc-shaped groove 58, 78 Core MP, MP1, MP2 Twin-screw kneading extruder MP ', MP1', MP2 'Single-screw kneading extruder 11 Rotating shaft 15, 23 Extrusion rotor 17 Rotor body 19 Kneading rotor 171 to 173 Wing 29, 31 Undermixer

Claims (6)

A kneading rotor having a rotating shaft and a rotor body fitted and fixed to the outer periphery of the rotating shaft,
The rotor body is formed with kneading blades on the outer surface and a plurality of disk-shaped grooves extending from the inner peripheral surface in contact with the rotating shaft toward the outer surface in the axial direction of the shaft. , Configured to circulate a cooling medium through each of the disk-shaped grooves,
A core extending from the inner peripheral surface of the front rotor body toward the outer surface is disposed in each disk-shaped groove, and the depth of the disk-shaped groove is substantially reduced by the core. A kneading rotor.   The kneading rotor according to claim 1, wherein the kneading rotor is applied to a kneading rotor of a batch kneader.   The kneading rotor according to claim 1, wherein the kneading rotor is applied to a kneading rotor of a twin-screw kneading extruder.   The kneading rotor according to claim 1, wherein the kneading rotor is applied to a kneading rotor of a uniaxial kneading extruder.   The kneading wing portion includes at least one long wing portion, and the twist angle of the long wing portion with respect to the axis of the shaft is set to 35 ° to 55 °. Rotor for kneading.   The kneading wing includes a first wing that is a long wing, a second wing and a third wing that are short wings, and a twist angle of the first wing with respect to the axis of the shaft; 5. The kneading rotor according to claim 3, wherein a twist angle of at least one of the second wing portion and the third wing portion with respect to the axis is set to 35 ° to 55 °.

Images