JP6144981B2 - Rubber member manufacturing equipment - Google Patents

Description

  The present invention relates to a rubber member manufacturing apparatus that can suppress deterioration in quality of a rubber member, particularly when a rubber member is formed by spirally winding a low heat-generating rubber strip.

  In recent years, long unvulcanized rubber strips are spirally wound and pasted on a former so that rubber members for tires such as tread rubber, sidewall rubber, and clinch rubber can be wound on rubber strips. An apparatus for manufacturing a rubber member formed on a former as a body has been proposed in Patent Document 1 below.

  As shown in FIG. 9, the manufacturing apparatus a includes at least a rubber strip supply means b for supplying the rubber strip Gs while extruding it and a former c around which the rubber strip Gs from the rubber strip supply means b is wound. Prepare.

  In the manufacturing apparatus a, it is necessary to stop the supply of the rubber strip Gs until the formed rubber member is removed from the former c and the next formation is started. Therefore, as the rubber strip supply means b, an extrusion head e having a gear pump e1 is attached to the front end portion of the screw type extruder main body d so that the rubber strip Gs is intermittently extruded in synchronization with the rotation of the former c. doing.

  In this case, the amount of rubber discharged from the gear pump e1 varies depending on the rubber pressure from the extruder main body d supplied to the gear pump e1. For this reason, the rotation of the screw shaft d1 of the extruder body d is controlled so that the pressure on the inlet side of the gear pump e1 is always constant, and the formation accuracy of the rubber strip Gs is improved.

  On the other hand, for tires, the development of rubber blends dedicated to low fuel consumption with low tangent loss is being promoted to improve fuel efficiency. However, this type of compounded rubber generally has a low exothermic property in order to reduce rolling resistance, and has a characteristic of poor so-called “heatability” that cannot be sufficiently plasticized during rubber processing. Therefore, when this compounded rubber is used in the manufacturing apparatus a, the plasticization becomes insufficient, and the rubber strip Gs is out of rubber, has a bad width, and a “hole” occurs after being attached to the former c. Problems arise.

  Further, in terms of making the pressure on the inlet side of the gear pump e1 constant, there is a problem of pressure follow-up that seems to be related to the rubber relaxation time (the amount of rubber feed relative to the rotation of the screw shaft d1). The problem that pressure tracking is delayed rather than linear) has occurred conventionally. In particular, when the gear pump accelerates from a low discharge amount to a high discharge amount, the rubber supply amount is insufficient, and the rubber strip Gs is cut.

JP 2012-254535 A

  Therefore, the present invention can increase the heat-insertability into rubber without increasing the size of the apparatus, and particularly when low-heat-generating rubber is used, the strip is out of rubber, the width is poor, and the rubber member is formed. It is an object of the present invention to provide a rubber member manufacturing apparatus that can suppress perforation and also stabilize the pressure on the inlet side of the gear pump when changing the discharge amount.

The present invention is a rubber member manufacturing apparatus for forming a rubber member composed of a wound body of the rubber strip by sticking a long rubber strip while spirally winding on a former,
A former driven to rotate around the axis;
A rubber strip supply means for supplying the rubber strip while extruding in synchronization with the rotation of the former;
The rubber strip supply means includes
An extruder body in which a screw shaft in which a spiral rubber feed groove by a screw blade is formed on the outer periphery of the base shaft is rotatably arranged in the cylinder;
An extrusion head having a gear pump attached to a front end portion of the extruder main body and for extruding rubber from the extruder main body in synchronization with rotation of a former;
Moreover, a damming region having a passage portion for damming the rubber passing through the rubber feed groove and passing a part thereof is provided in the middle of the screw shaft.

In the rubber member manufacturing apparatus according to the present invention, the screw shaft has a rubber feed groove formed by two screw blades provided on an outer periphery of the base shaft,
In the damming region, one screw blade of the two screw blades is a screw blade having a different pitch from the other screw blade. In the section, an intersection where the screw blades of the different pitch and the other screw blades intersect is formed,
It is preferable that the rubber in the rubber feed groove is dammed by forming the crossing portion, and a part of the rubber is passed over at least one screw blade.

  In the rubber member manufacturing apparatus according to the present invention, the height of one of the intersecting screw blades is made lower than the height of the other screw blade in the damming region, or It is preferable to form the passage portion through which a part of the rubber passes by providing a plurality of small grooves at the tip.

  In the rubber member manufacturing apparatus according to the present invention, the rubber strip supply means includes a calendar roll machine for rolling the rubber extruded from the extrusion head into a rubber strip having a final thickness in front of the extrusion head. It is preferable.

  In the rubber member manufacturing apparatus according to the present invention, the rubber strip supply means may not include exhaust means for sucking and exhausting air in the cylinder.

  As described above, the rubber strip supply means according to the present invention has a passage portion for damming the rubber passing through the rubber feed groove and passing a part thereof in the middle of the screw shaft provided with the rubber feed groove. A blocking area is provided. Thereby, rubber | gum generate | occur | produces heat | fever by the shearing effect at the time of passing, and heat-adding property improves. Moreover, since the rubber is once thinned (or thinned) during passage, the plasticity of the rubber can be sufficiently increased in combination with the heat generation, and the rubber strip Gs after extrusion is out of rubber, has poor width, and rubber. Hole formation after forming the member can be suppressed.

  Further, the improvement in the plasticity increases the linearity of the rubber feed amount with respect to the rotation of the screw shaft. That is, pressure followability increases. For this reason, the accuracy of pressure control (control of the pressure on the inlet side of the gear pump) by the rotation control of the screw shaft can be improved, and particularly when the gear pump is accelerated from a low discharge amount to a high discharge amount, rubber is supplied to the gear pump. The amount can be stabilized.

It is a side view which shows one Example of the manufacturing apparatus of the rubber member of this invention. It is sectional drawing of the longitudinal direction which expands and shows a rubber strip supply means. It is a partial side view which shows a screw shaft. It is the conceptual diagram which expand | deployed the screw shaft surface in the plane. It is a conceptual diagram explaining the flow of rubber. (A), (B) is sectional drawing which shows notionally the rubber climbing state in a damming part. It is sectional drawing of the longitudinal direction of the screw shaft which shows the other Example of a damming part. (A), (B) is the graph which measured the pressure of the inlet side of a gear pump in Table 1. FIG. It is a side view of the manufacturing apparatus of the rubber member for tires of a prior art example.

Hereinafter, embodiments of the present invention will be described in detail.
As shown in FIG. 1, the rubber member manufacturing apparatus 1 (hereinafter referred to as “manufacturing apparatus 1”) of the present invention applies a long tape-shaped rubber strip Gs made of unvulcanized rubber on a former 2. A rubber member made of a wound body of the rubber strip Gs is formed by spirally winding and sticking. In this example, the case where the manufacturing apparatus 1 forms a rubber member for a tire such as a tread rubber, a side wall rubber, and a clinch rubber on the tire forming former 2T is shown.

  The manufacturing apparatus 1 includes at least a former 2 and rubber strip supply means 3 that supplies the rubber strip Gs while being extruded in synchronization with the rotation of the former 2. In this example, the case where the manufacturing apparatus 1 further includes an actuator 4 that guides and attaches the rubber strip Gs from the rubber strip supply means 3 to the former 2 is shown.

  The former 2 is, for example, a cylindrical drum that is rotationally driven around the axis j, and in this example, is supported by the traveling platform 5 so as to be movable in the axis direction. The former 2 is not limited to this, and various forms such as a toroidal shape whose outer shape approximates the tire shape can be adopted.

  The rubber strip supply means 3 includes a screw-type extruder main body 6 and an extrusion head 7 attached to the front end portion thereof.

  As shown conceptually in FIG. 2, the extruder body 6 includes a cylindrical cylinder 8 and a screw shaft 9 that is rotatable and concentrically disposed in the cylinder 8. Then, the material rubber G introduced from the insertion port 8A provided on the rear end side of the cylinder 8 is pushed up to the front end extrusion port 8B while being plasticized by the rotation of the screw shaft 9. The screw shaft 9 is rotationally controlled by a driving device M (shown in FIG. 1) connected to the rear end thereof.

  The extrusion head 7 includes a gear pump 7A and a base 7B. The gear pump 7A is a constant volume extruder having a well-known structure, and includes a casing 10 attached to a front end portion of the extruder body 6 and a pair of push gears 11 and 11 disposed in the casing 10. The base 7B has a block shape in which a molding port 7B1 is opened at the front end, and is replaceably attached to the front end side of the gear pump 7A. The extrusion head 7 rotates the extrusion gear 11 with an electric motor (not shown), thereby causing the plasticized rubber G from the extruder main body 6 to synchronize with the rotation of the former 2 from the molding port 7B1. Extrude.

  The rubber strip supply means 3 of this example further includes a calendar roll machine 15 in front of the extrusion head 7. The calender roll machine 15 includes upper and lower calender rolls 15a and 15b, and rolls the rubber G extruded through the molding port 7B1 into a rubber strip Gs having a final thickness. The upper and lower calendar rolls 15a and 15b are driven in synchronism with the rotation of the former 2 like the gear pump 7A. The “synchronization” includes a case where there is a predetermined time difference with respect to the rotation operation of the former 2 in addition to the rotation operation of the former 2.

  Next, the screw shaft 9 includes a base shaft 16 and screw blades 17 wound spirally around the base shaft 16. Thereby, a spiral rubber feed groove 18 is formed between the screw blades 17. In the middle of the screw shaft 9, there is provided a damming region Y having a passage portion 19 (shown in FIG. 6) for damming the rubber G passing through the rubber feed groove 18 and passing a part thereof.

  In this example, as shown in FIGS. 3 and 4, the screw shaft 9 includes two screw blades 17 </ b> A and 17 </ b> B on the outer periphery of the base shaft 16, thereby forming two rubber feed grooves 18 </ b> A and 18 </ b> B. FIG. 4 is a conceptual diagram in which the surface of the screw shaft 9 of FIG. In the damming region Yc, one screw blade 17A of the two screw blades 17A and 17B is formed as a screw blade 20 having a different pitch from that of the other screw blade 17B.

  Specifically, the one screw blade 17A is disposed in the front and rear blade portions 17Af and 17Ar disposed in the front region Yf and the rear region Yr with respect to the dam region Yc, and the dam region Yc. It is divided into a central blade portion 17Ac. The central blade portion 17Ac is formed from screw blades 20 having different pitches, and the front and rear blade portions 17Af and 17Ar are formed from screw blades 21 having the same pitch as the other screw blades 17B and having the same pitch length P. Is done. The rear end Er of the front blade portion 17Af is separated from the front end ef of the central blade portion 17Ac upstream of the rubber flow, and the front end Ef of the rear blade portion 17Af is rubber from the rear end er of the central blade portion 17Ac. Separated downstream of the flow.

  In particular, in this example, the central blade portion 17Ac is formed from the first and second blade portions 17Ac1, 17Ac2, and the first blade portion 17Ac1 is more elastic than the second blade portion 17Ac2. The position is shifted downstream. The rear end Er of the front blade portion 17Af is separated from the front end ef of the second blade portion 17Ac2 upstream of the rubber flow, and the front end Ef of the rear blade portion 17Ar is the rear end of the first blade portion 17Ac1. from the er to the downstream side of the rubber flow.

  The pitch length P2 of the first and second blade portions 17Ac1 and 17Ac2 is different from the pitch length P1 of the other screw blade 17B (P2> P1 in this example). As a result, intersections J1f and J1r where the first blade portion 17Ac1 and the other screw blade 17B intersect are formed at both ends of the first blade portion 17Ac1. Further, at both ends of the second blade portion 17Ac2, intersections J2f and J2r where the second blade portion 17Ac2 and the other screw blade 17B intersect are formed. By forming the intersections J1f, J1r, J2f, and J2r, the rubber G in the rubber feed groove 18 is dammed and a part of the rubber G passes over at least one screw blade 17 and passes therethrough.

  More specifically, as shown in FIG. 5, the two rubber feed grooves 18A and 18B in the rear region Yr are changed to one first groove 18C1 upstream of the rear blade portion 17Ar. Join. Thereafter, the first blade portion 17Ac1 extends so as to branch from the other screw blade 17B, and thereby the second groove 18C2 is formed to branch from the first groove 18C1. At this time, after the first groove 18C1 is branched, the groove width is gradually narrowed, and the front end thereof is blocked by the intersecting portion J1f. Thus, the rubber G in the first groove 18C1 moves over the first blade portion 17Ac1 and moves into the adjacent second groove 18C2.

  In the second groove 18C2, the second blade portion 17Ac2 extends so as to branch from the other screw blade 17B. As a result, the third groove 18C3 is branched from the second groove 18C2. At this time, the front end ef of the second groove 18C2 is blocked by the intersection J2f. As a result, the rubber G in the second groove 18C2 moves over the second blade portion 17Ac2 and moves into the adjacent third groove 18C3.

  The third groove 18C3 forms one merge groove after the intersection J2f, and thereafter, is divided into two rubber feed grooves 18A and 18B in the front region Yf.

  In this example, the first groove 18C1 and the second groove 18C2 are dammed up at the intersections J1f and J2f, respectively. Transition from the first groove 18C1 through the second groove 18C2 to the third groove 18C3. In other words, two rides are performed. Note that the central blade portion 17Ac can be formed only by the first blade portion 17Ac1, and in this case, it can be climbed only once.

  The overcoming of the rubber G is performed, for example, by making the height of one screw blade 17A (or 17B) of the intersecting screw blades 17A, 17B lower than the height of the other screw blade 17B (or 17A). Is called. In this case, as shown in FIG. 6A, the rubber G is formed into a thin film through a gap 22 formed between the outer peripheral surface of the low screw blade 17A (or 17B) and the inner peripheral surface of the cylinder 8. Deformed and passes. Further, as shown in FIG. 6B, a plurality of small grooves 23 are formed at the tip of one screw blade 17A (or 17B). Accordingly, the rubber G can pass through the small groove 23 while being deformed into a thin thread shape. That is, the passage portion 19 is formed by the gap 22 and the small groove 23.

  As described above, when the rubber G passes through the passage portion 19, the rubber G shears and deforms, and the rubber itself generates heat, so that the heat insertion property is improved. In addition, the rubber G is once softly deformed into a thin film shape or a thin thread shape when passing, and the plasticity of the rubber can be sufficiently increased in combination with the heat generation. The crossing angle θ (shown in FIG. 4) of the screw blades 17A and 17B is preferably 7 to 15 degrees.

  Further, as shown in FIG. 7, the screw blade 17 of the screw shaft 9 is provided with a discontinuity portion 24 having a width D, and a disc-shaped weir plate 25 that is concentrically attached to the base shaft 16 is provided at the position of the discontinuity portion 24. By arranging, the damming region Yc can be formed by the damming plate 25. In this case, the passage portion 19 is formed by, for example, a gap 22 between the inner peripheral surface of the cylinder 8 and the outer peripheral surface of the damming plate 25 or a plurality of small grooves 23 formed on the outer peripheral surface of the damming plate 25. be able to. In this case, the rubber feed groove 18 of the screw shaft 9 may be one or two.

  The damming region Yc is also suitable for separating the air contained in the rubber G. However, the present application is intended to improve the plasticity. Therefore, the rubber strip supply means 3 does not have to be provided with an exhaust means for sucking and exhausting the air in the cylinder 8 by, for example, a vacuum pump.

  As mentioned above, although especially preferable embodiment of this invention was explained in full detail, this invention is not limited to embodiment of illustration, It can deform | transform and implement in a various aspect.

  In order to confirm the effect of the present invention, a rubber member manufacturing apparatus having the structure shown in FIG. 1 was prepared based on the specifications in Table 1, and a tire rubber member (tread rubber) having a tangent loss tan δ = 0.12. Manufactured using rubber compounded specifically for low fuel consumption. The tangent loss is a value at a temperature of 30 ° C. and an amplitude of 2%. Then, the heat-insertability in the rubber strip supply means and the stability of the pressure on the inlet side of the gear pump were tested.

  Each device is different only in the specifications of the extruder body (shown in Table 1).

(1) Heatability:
By visual inspection, whether or not the plasticization of the rubber is sufficiently and uniformly performed over the entire surface, the smoothness of the surface of the rubber strip extruded from the rubber strip supply means, and the occurrence of undulation (fluctuation) during extrusion The state etc. were judged macroscopically and evaluated in four stages. The larger the numerical value, the better and more uniform the plasticization and the better the heat input.

(2) Pressure stability:
Using a conventional control device, the screw shaft was driven to rotate in synchronization with the gear pump, and pressure control was performed so that the pressure on the inlet side of the gear pump was constant. The gear pump was changed from a low speed to a high speed, and the pressure fluctuation on the inlet side of the gear pump in the pressure control state was measured. The measurement results are shown in FIGS. 8A and 8B. The flatter the pressure fluctuation curve, the better the stability.

  As shown in the table, since the extruder main body of the example has a damming region, it can be confirmed that the heat injection property is excellent and the plasticization of the rubber is sufficiently and uniformly performed. Further, since the rubber in the extruder body is also excellent in plasticity, the amount of rubber fed with respect to the rotation of the screw shaft becomes linear. Therefore, in the embodiment, it can be confirmed that the accuracy of pressure control is improved and the pressure on the inlet side of the gear pump can be stabilized.

DESCRIPTION OF SYMBOLS 1 Rubber member manufacturing apparatus 2 Former 3 Rubber strip supply means 6 Extruder main body 7 Extrusion head 7A Gear pump 8 Cylinder 9 Screw shaft 15 Calendar roll machine 16 Base shaft 17, 17A, 17B Screw blades 18, 18A, 18B Rubber feed groove 19 Passing Part Gs Rubber strip Yc Damping area

Claims (7)

A rubber member manufacturing apparatus for forming a rubber member composed of a wound body of the rubber strip by sticking a long rubber strip while being spirally wound on a former,
A former driven to rotate around the axis;
A rubber strip supply means for supplying the rubber strip while extruding in synchronization with the rotation of the former;
The rubber strip supply means includes
An extruder body in which a screw shaft in which a spiral rubber feed groove by a screw blade is formed on the outer periphery of the base shaft is rotatably arranged in the cylinder;
An extrusion head having a gear pump attached to a front end portion of the extruder main body and for extruding rubber from the extruder main body in synchronization with rotation of a former;
Moreover, in the middle of the screw shaft, a damming region having a passing portion for damming the rubber passing through the rubber feed groove and passing a part thereof is provided ,
The screw shaft has a rubber feed groove formed by two screw blades provided on the outer periphery of the base shaft.
In the damming region, one screw blade of the two screw blades is a screw blade having a different pitch from the other screw blade,
Furthermore, in the damming region, the one screw blade is formed from a first blade portion and a second blade portion,
The apparatus for producing a rubber member, wherein the first blade portion is arranged to be shifted to a downstream side of the rubber flow as compared with the second blade portion . At both ends of the screw blade of the prior Ki違pitch, together with the cross section of intersection between the screw blade and the other screw blade of該違pitch is formed,
2. The apparatus for producing a rubber member according to claim 1, wherein by forming the intersecting portion, the rubber in the rubber feed groove is dammed and a part of the rubber is passed over at least one screw blade.   In the damming region, the height of one screw blade of the intersecting screw blades is made lower than the height of the other screw blade, or a plurality of small grooves are provided at the tip of one screw blade, thereby 3. The apparatus for manufacturing a rubber member according to claim 2, wherein the passage portion through which a portion passes is formed.   The said rubber strip supply means is equipped with the calender roll machine which rolls the rubber extruded from this extrusion head to the rubber strip of final thickness ahead of the said extrusion head. An apparatus for producing a rubber member according to claim 1.   5. The rubber member manufacturing apparatus according to claim 1, wherein the rubber strip supply means does not include exhaust means for sucking and exhausting air in the cylinder. The one screw blade is a screw blade having the same pitch as that of the other screw blade in the front region and the rear region from the damming region. The manufacturing apparatus of the rubber member of description. A rubber member manufacturing apparatus for forming a rubber member composed of a wound body of the rubber strip by sticking a long rubber strip while being spirally wound on a former,
  A former driven to rotate around the axis;
  A rubber strip supply means for supplying the rubber strip while extruding in synchronization with the rotation of the former;
  The rubber strip supply means includes
    An extruder body in which a screw shaft in which a spiral rubber feed groove by a screw blade is formed on the outer periphery of the base shaft is rotatably arranged in the cylinder;
    An extrusion head having a gear pump attached to a front end portion of the extruder main body and for extruding rubber from the extruder main body in synchronization with rotation of a former;
  Moreover, in the middle of the screw shaft, a damming region having a passing portion for damming the rubber passing through the rubber feed groove and passing a part thereof is provided,
The screw shaft has a rubber feed groove formed by two screw blades provided on the outer periphery of the base shaft.
  In the damming region, one screw blade of the two screw blades is a screw blade having a different pitch from the other screw blade,
  Manufacturing of a rubber member characterized in that, in the front region and the rear region from the damming region, the one screw blade is a screw blade having the same pitch as that of the other screw blade. apparatus.

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