JP2018030345A - Production device for rubber member, and manufacturing method for pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production technique for a rubber member capable of producing the rubber member including no stop mark even in a strip winding method using the rubber blended as such a member of a tire for car race.SOLUTION: A rubber member production device includes producing the rubber member for tire by continuously winding up a rubber strip continuously extruded from a rubber extruder on a molding drum. The device is equipped with: the extruder having a rubber extruder body having a screw shaft advancing an unvulcanized rubber while kneading, and a gear pump connected to the discharge port of the extruder body; a calender head processing the rubber strip extruded from the extruder into a prescribed cross-sectional shape; and an applicator receiving the rubber strip from the calender head and conveying to the molding drum to wind up the prescribed length of the strip. A torus part is formed at the central part of the molding drum, and the cylindrical parts are formed at both sides of the torus part.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a rubber member manufacturing apparatus and a pneumatic tire manufacturing method using a strip wind method.

  In manufacturing a pneumatic tire, in recent years, a rubber member is formed by continuously winding a tape-shaped unvulcanized rubber material (rubber strip) continuously extruded from an extrusion device around a cylindrical molding drum. The strip wind method is used.

  At this time, the type equipped with a screw has been the mainstream as an extrusion device.However, if the extrusion device is frequently stopped and operated, stable rubber extrusion cannot be performed. Establishing a festoon. However, when a festoon is introduced, the extruded rubber strip is left for a long time until molding, and the physical properties of the rubber may change.

  Thus, it has been proposed to stabilize the discharge amount by combining a gear pump instead of the festoon (Patent Document 1).

  However, in this case, when the rubber strip is extruded intermittently, the thickness of the rubber strip becomes nearly double, and a so-called stop mark may be formed at the winding start end. The place where such a stop mark is formed may be a starting point of breakage in the high-speed durability test.

  Therefore, as a method for preventing the generation of such a stop mark, the control of the calendar roll is changed so as to reduce the pressure while suppressing the extrusion and to delay the deceleration time (Patent Document 2), or the part whose shape has changed Is placed on the bottom of the tire groove so that it is crushed by the convex portion of the mold during vulcanization, thereby reducing the influence of the change in shape.

JP 2014-73590 A Japanese Patent No. 5869998

  However, although each of the above methods is effective for tires used on general roads, it cannot be said to be sufficient for a tread member of a tire for automobile racing, and further improvement has been demanded.

  Accordingly, the present invention provides a rubber member manufacturing technique capable of manufacturing a rubber member that does not include a stop mark even in a strip wind method using rubber compounded as a rubber member of an automobile racing tire. Let it be an issue.

  The inventor has intensively studied and found that the above-described problems can be solved by the invention described below, and has completed the present invention.

The invention described in claim 1
A rubber member manufacturing apparatus for manufacturing a rubber member for a tire by continuously winding a rubber strip continuously extruded from a rubber extrusion device on a molding drum,
An extruder having a rubber extruder main body having a screw shaft that advances while kneading unvulcanized rubber, and a gear pump connected to a discharge port of the extruder main body,
A calendar head for processing the rubber strip extruded from the extrusion device into a predetermined cross-sectional shape;
An applicator that receives the rubber strip from the calendar head, conveys the rubber strip to the molding drum, and rolls it over a predetermined length;
In the rubber member manufacturing apparatus, a torus portion is formed in a central portion of the molding drum, and cylindrical portions are formed on both sides of the torus portion.

The invention described in claim 2
2. The rubber member manufacturing apparatus according to claim 1, wherein the molding drum has a concave circumferential groove near a boundary between the torus part and the cylindrical part.

The invention according to claim 3
A pneumatic tire manufacturing method for manufacturing a pneumatic tire by a strip wind method using the rubber member manufacturing apparatus according to claim 1,
Using the applicator, conveying the rubber strip to the molding drum, starting winding from one side of the cylindrical portion, and winding up a predetermined length,
The end of the rubber strip is continuously wound around the torus part, and the winding is finished at the other end of the cylindrical part,
A pneumatic tire characterized in that the rubber strip wound is cut at a boundary between the torus portion and the cylindrical portion, and a green tire is molded using the rubber strip wound around the torus portion. It is a manufacturing method.

The invention according to claim 4
A pneumatic tire manufacturing method for manufacturing a pneumatic tire by a strip wind method using the rubber member manufacturing apparatus according to claim 2,
Using the applicator, conveying the rubber strip to the molding drum, starting winding from one side of the cylindrical portion, and winding up a predetermined length,
The end of the rubber strip is continuously wound around the torus part, and the winding is finished at the other end of the cylindrical part,
A pneumatic tire characterized in that the rubber strip wound is cut on the concave circumferential groove with a disk-shaped blade, and a green tire is molded using the rubber strip wound around the torus portion. A tire manufacturing method.

The invention described in claim 5
5. The concave circumferential groove of the molding drum used in the rubber member manufacturing apparatus is formed to have a groove width of 1/2 or less of a rubber strip width and a depth of 5 mm or more. It is a manufacturing method of the pneumatic tire of description.

The invention described in claim 6
The pneumatic tire manufacturing method according to any one of claims 3 to 5, wherein the manufactured pneumatic tire is an automobile racing tire.

  ADVANTAGE OF THE INVENTION According to this invention, even in the strip wind method using the rubber | gum mix | blended as a rubber member of the tire for motor racing, the manufacturing method of the rubber member which can manufacture the rubber member which does not contain a stop mark is provided. it can.

It is a whole side view including the partial cross section of the manufacturing apparatus of the rubber member which concerns on one embodiment of this invention. It is a perspective view which shows the forming drum which concerns on one embodiment of this invention. It is sectional drawing which shows the principal part of the state which wound the rubber strip around the molding drum which concerns on one embodiment of this invention.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is an overall side view including a partial cross section of the rubber member manufacturing apparatus according to the present embodiment. As shown in FIG. 1, this rubber member manufacturing apparatus 1 supplies a tape-shaped rubber strip GS made of unvulcanized rubber and winds it around the outer periphery of a molding drum 6 to manufacture a rubber member for a pneumatic tire. To do.

  The rubber member manufacturing apparatus 1 according to the present embodiment is characterized by a molding drum 6. That is, FIG. 2 is a perspective view showing the forming drum 6. The forming drum 6 is provided at the central portion, the torus portion 6a having a diameter increasing from both sides toward the central portion, and provided on both sides of the torus portion 6a. And a pair of cylindrical portions 6b and 6c.

  Then, after the rubber strip is conveyed to the molding drum 6 and wound around the cylindrical portion 6b of the molding drum 6 for a predetermined length, the extrusion of the rubber strip is not stopped and the tip of the rubber strip is wound around the torus portion 6a. The other cylindrical part 6c is wound up and completed.

  Thereby, the stop mark is formed on the cylindrical portions 6b and 6c, but not on the torus portion 6a. Then, the rubber strip wound at the boundary between the cylindrical portions 6b and 6c and the torus portion 6a is cut, and a raw tire is molded using only the rubber strip of the torus portion 6a. Also in the strip wind method using the compounded rubber, it is possible to prevent the stop mark from being formed on the raw tire and to exhibit excellent high-speed durability.

  Hereinafter, the rubber member manufacturing apparatus and the pneumatic tire manufacturing method according to the present embodiment will be described in detail.

  First, a rubber member manufacturing apparatus will be described.

  As shown in FIG. 1, the rubber member manufacturing apparatus 1 includes a rubber extruding apparatus 2, a calendar head 3 disposed on the downstream side in the rubber extruding direction X, and an applicator 5 provided on the downstream side of the calendar head 3. And a forming drum 6 provided on the downstream side of the applicator 5.

  The rubber extruding device 2 preliminarily molds and extrudes the charged rubber G1, and extrudes the rubber extruder main body 7, the gear pump 8 provided on the downstream side thereof, and the extrusion provided on the downstream side of the gear pump 8. And a head 9.

  The rubber extruder body 7 includes a cylinder 7a provided with an inlet 7c for the rubber G1, and a screw shaft 7b disposed in the cylinder 7a. The screw shaft 7b is rotationally driven by an electric motor (not shown), and discharges the charged rubber G1 from the discharge port J at the front end of the cylinder 7a while kneading.

  The gear pump 8 is a constant volume pump provided with a pair of extrusion gears 8b arranged in the casing 8a. The upstream side of the gear pump 8 communicates with the discharge port J of the rubber extruder body 7. Further, the downstream side of the gear pump 8 communicates with the extrusion head 9.

  The pushing gear 8b is driven to rotate by an electric motor (not shown). Thereby, rubber | gum G1 is satisfy | filled between the tooth space of the extrusion gear 8b, and the casing 8a, and is quantitatively pumped from an exit.

  The extrusion head 9 includes a block-like head main body 9a that is replaceably connected to the casing 8a of the gear pump 8, and a base 9b that is attached to the head main body 9a in a replaceable manner. A preforming port is opened in the base 9b. Accordingly, the kneaded rubber G1 is extruded as a rubber molded body G2 from a preforming port having a predetermined shape of the extrusion head 9.

  The calendar head 3 includes a pair of calendar rolls 3a and 3b arranged vertically. Each calendar roll 3a, 3b is configured to be rotationally driven in the opposite direction by an electric motor. In the calendar head 3, the rubber strip GS is manufactured by rolling the rubber molded body G2 between the calendar rolls 3a and 3b and with a predetermined calendar pressure.

  The applicator 5 includes a conveyor 5 a and conveys the rubber strip GS to the molding drum 6.

  As is apparent from FIG. 1, the rubber member manufacturing apparatus according to the present embodiment does not use a festoon. This is due to the following reason.

  In other words, tread compounds used in automobile racing tires contain more oil than ordinary tire compounds in order to achieve a high grip, are likely to cause changes in physical properties, and are very sticky. This is because it is difficult to transport by festoon due to its high performance.

  Specifically, when measured with a tack meter, the adhesion of the race compound is 5.0 to 7.0, whereas the general compound is 1.0 to 3.0. This is because a festoon cannot be used for tread strip winding, and if the control of the calendar head is changed, there is a risk that contact troubles may occur.

  FIG. 2 is a perspective view showing a molding drum, and FIG. 3 is a cross-sectional view showing a main part in a state where a rubber strip is wound around the molding drum. As described above, the forming drum 6 includes the torus portion 6a that is provided at the center portion and increases in diameter from both sides toward the center portion, and the pair of cylindrical portions 6b and 6c that are provided on both sides of the torus portion 6a. I have. The molding drum 6 is supported by the molding drum support device 10 (FIG. 1) and is rotationally driven.

  The molding drum 6 preferably has a concave circumferential groove 6d formed continuously in the circumferential direction in the vicinity of the boundary between the torus portion 6a and the cylindrical portions 6b and 6c. The concave circumferential groove 6d has a groove width W1 that is less than or equal to one half of the rubber strip width W2, more preferably one third to one fifth of the rubber strip width W2, and more preferably 5 mm or more, It is preferable to be formed to a depth H of 5 to 10 mm.

  Next, a method for manufacturing a pneumatic tire using the rubber member manufacturing apparatus 1 according to the above-described embodiment will be described.

  As shown in FIG. 1, the rubber molded body G <b> 2 extruded from the rubber extrusion device 2 is rolled by the calendar head 3. By this rolling, a thin rubber strip GS having a preset size is continuously obtained. The rubber strip GS is supplied to the applicator 5 without interposing a festoon or the like.

  In the applicator 5, the rubber strip GS is conveyed to the molding drum 6 by the conveyor 5a.

  One end (tip) of the rubber strip GS is fixed to one cylindrical portion 6 b of the molding drum 6, and the rubber strip GS is sequentially wound by the rotation of the molding drum 6. After being wound on the cylindrical portion 6b for a predetermined length, it is continuously wound on the torus portion 6a (see FIG. 3). Even if the stop mark is formed on the rubber strip GS, since the stop mark is formed on the end of the rubber strip GS, the stop mark is wound around the cylindrical portion 6b and the torus portion 6a. Then, the rubber strip GS is wound to a stable thickness.

  In particular, the tread gauge of automobile racing tires is as thin as 4 mm or less, and by simply extruding rubber compounded for automobile racing by a gear pump system, a stop mark with a thickness of 3 to 4 mm is formed. A part is formed, and this becomes a starting point of damage in the high-speed durability test of the tire. Therefore, by performing the above, a particularly remarkable effect is exhibited in the case of the rubber strip GS for automobile tires.

  If necessary, by moving the forming drum 6 as appropriate, the winding pitch of the rubber strip GS can be changed to form rubber members having various cross-sectional shapes.

  Since the molding drum 6 has a circumferential groove 6d in the vicinity of the boundary between the torus portion 6a and the cylindrical portions 6b and 6c, the circumferential groove 6d is cut by the disk-shaped blade 11 after the rubber strip GS is wound. As a result, the rubber strip GS on the torus portion 6a is separated from the rubber strip GS on the cylindrical portions 6b and 6c, and the rubber strip GS on the torus portion 6a is used as a tire member. Thereafter, a pneumatic tire is manufactured by an existing apparatus.

  As described above, according to the rubber strip manufacturing apparatus and the pneumatic tire manufacturing method of the present embodiment, unlike the conventional case, even a highly adhesive compound that could not be used conventionally is preferably used. Since it can be used, a stop mark is not formed even in a strip wind method using rubber compounded as a rubber member of an automobile racing tire.

  Hereinafter, the present invention will be described more specifically with reference to examples.

1. Preparation of Test Specimens A rubber tire having a width shown in Table 1 was wound around a molding drum to form a raw tire, and then vulcanized to produce ten race tires each having a tire size of 300 / 680R18 SLICK.

  The tack of the rubber strip used was a Toyo Seiki tack meter in accordance with JIS T 9233, with a pressure load of 4.9 N, a peeling speed of 10 mm / min, and a reference sample size of 12.7 mm × It was 7.0 when measured under the conditions of 152 mm, pressure bonding time: 10 seconds.

(1) Example 1
Using a forming drum in which a cylindrical portion having a diameter of 648 mm and a length of 100 mm is provided on both sides of a torus portion having a maximum diameter of 688 mm and a width of 318 mm, 4 m is wound around one cylindrical portion, Wrapping 120m so as to overlap at a pitch of 6mm, finishing the winding with the other cylindrical part as the terminal part, as shown in Fig. 3, cut on both sides of the torus part using a disc-shaped blade with a diameter of 100mm, A green tire was molded using as a tread member.

(2) Examples 2 to 5
A concave circumferential groove having a width and depth shown in Table 1 was formed at the boundary between the torus part and the cylindrical part, and a raw tire was molded in the same manner as in Example 1 except that the groove was cut by this groove.

(3) Comparative Example 1
A raw tire was molded in the same manner as in Example 1 except that the cylindrical portion was not provided.

2. Evaluation (1) Presence / absence of cut defects and stop marks The occurrence of cut defects and the occurrence of stop marks in the green tire molding process were observed visually.

(2) High-speed durability Each manufactured tire was mounted, and after running for 10 minutes at 230 km / h, the tires were accelerated every other minute by 10 km / h. When it was able to run for 1 minute or more at 310 km / h, it was determined that it was suitable for high-speed durability.

(3) Evaluation results Table 1 shows the evaluation results.

  From Table 1, in Comparative Example 1, while the stop mark that was present at a point of 2.5 m after extrusion remained after the green tire molding, Examples 1 to 1 in which the cylindrical portion was provided on the molding drum 5 shows that the stop mark is gone. Further, it can be seen that in Comparative Example 1, high-speed durability was incompatible, while in Examples 1 to 5, it was in conformity.

  In Examples 1, 2, and 5, cut defects occurred, but Example 3 in which a concave circumferential groove was formed at a groove width of 1/2 or less of the rubber strip width and a depth of 5 mm or more. 4 shows that no cut defect occurs.

  While the present invention has been described based on the embodiments, the present invention is not limited to the above-described embodiments. It should be noted that various modifications can be made to the above embodiment within the same and equivalent scope as the present invention.

DESCRIPTION OF SYMBOLS 1 Rubber member manufacturing apparatus 2 Rubber extrusion apparatus 3 Calendar head 3a, 3b Calendar roll 5 Applicator 5a Conveyor 6 Molding drum 6a Torus part 6b, 6c Cylindrical part 6d Circumferential groove 7 Rubber extruder main body 7a Cylinder 7b Screw shaft 7c Feed port 8 Gear pump 8a Casing 8b Extrusion gear 9 Extrusion head 9a Head body 9b Base 10 Molding drum support device 11 Disc-shaped blade G1 Rubber G2 Rubber molding GS Rubber strip H Depth J Discharge port W1 Groove width W2 Rubber strip width X Rubber extrusion direction

Claims (6)

A rubber member manufacturing apparatus for continuously rolling a rubber strip extruded from a rubber extrusion device on a molding drum to manufacture an annular rubber member for a tire,
An extruder having a rubber extruder main body having a screw shaft that advances while kneading unvulcanized rubber, and a gear pump connected to a discharge port of the extruder main body,
A calendar head for processing the rubber strip extruded from the extrusion device into a predetermined cross-sectional shape;
An applicator that receives the rubber strip from the calendar head, conveys the rubber strip to the molding drum, and rolls it over a predetermined length;
An apparatus for producing a rubber member, wherein a torus portion is formed at a central portion of the molding drum, and cylindrical portions are formed on both sides of the torus portion.   2. The rubber member manufacturing apparatus according to claim 1, wherein the molding drum has a concave circumferential groove in the vicinity of a boundary between the torus part and the cylindrical part. A pneumatic tire manufacturing method for manufacturing a pneumatic tire by a strip wind method using the rubber member manufacturing apparatus according to claim 1,
Using the applicator, conveying the rubber strip to the molding drum, starting winding from one side of the cylindrical part, and winding up a predetermined length,
The end of the rubber strip is continuously wound around the torus part, and the winding is finished at the other end of the cylindrical part,
A pneumatic tire characterized in that the rubber strip wound is cut at a boundary between the torus portion and the cylindrical portion, and a green tire is molded using the rubber strip wound around the torus portion. Manufacturing method. A pneumatic tire manufacturing method for manufacturing a pneumatic tire by a strip wind method using the rubber member manufacturing apparatus according to claim 2,
Using the applicator, conveying the rubber strip to the molding drum, starting winding from one side of the cylindrical portion, and winding up a predetermined length,
The end of the rubber strip is continuously wound around the torus part, and the winding is finished at the other end of the cylindrical part,
A pneumatic tire characterized in that the rubber strip wound is cut on the concave circumferential groove with a disk-shaped blade, and a green tire is molded using the rubber strip wound around the torus portion. Tire manufacturing method.   5. The concave circumferential groove of the molding drum used in the rubber member manufacturing apparatus is formed to have a groove width of 1/2 or less of a rubber strip width and a depth of 5 mm or more. The manufacturing method of the pneumatic tire of description.   The method for manufacturing a pneumatic tire according to any one of claims 3 to 5, wherein the manufactured pneumatic tire is an automobile racing tire.

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