JP6819015B2 - Rubber member manufacturing equipment and pneumatic tire manufacturing method - Google Patents

Description

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

In the manufacture of pneumatic tires, in recent years, a rubber member is formed by continuously winding a tape-shaped unvulcanized rubber material (rubber strip) continuously extruded from an extruder on a cylindrical molded drum. The strip wind method is used.

At this time, the type equipped with a screw has been the mainstream as an extruder, but if the extruder is stopped and operated frequently, stable rubber extrusion cannot be performed. Therefore, as a solution, the screw outlet is used. Festoons are being set up. However, when the festoon is introduced, the extruded rubber strip is left for a long period of time until molding, so that the physical characteristics of the rubber may change.

Therefore, 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 intermittently extruded, the thickness of the rubber strip is nearly doubled, and a so-called stop mark may be formed at the winding start end. The location where such a stop mark is formed may be the starting point of damage in the high-speed durability test.

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

Japanese Unexamined Patent Publication No. 2014-73590 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 tread members of automobile racing tires, and further improvement has been required.

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

The present inventor has conducted diligent studies and found that the above-mentioned problems can be solved by the invention described below, and has completed the present invention.

The invention according to claim 1
A rubber member manufacturing device that continuously winds rubber strips continuously extruded from a rubber extruder onto 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 an extruder having a gear pump connected to a discharge port of the extruder main body.
A calendar head that processes a rubber strip extruded from the extruder into a predetermined cross-sectional shape, and
It is provided with an applicator that receives the rubber strip from the calendar head, conveys it to the molding drum, and winds it for a predetermined length.
The molded drum has a torus portion formed in the center portion, and cylindrical portions are formed on both sides of the torus portion .
This is a rubber member manufacturing apparatus , characterized in that the molded drum has a concave peripheral groove near the boundary between the torus portion and the cylindrical portion .

The invention according to claim 2
A rubber member manufacturing device that continuously winds rubber strips continuously extruded from a rubber extruder onto 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 an extruder having a gear pump connected to a discharge port of the extruder main body.
A calendar head that processes a rubber strip extruded from the extruder into a predetermined cross-sectional shape, and
It is provided with an applicator that receives the rubber strip from the calendar head, conveys it to the molding drum, and winds it for a predetermined length.
A rubber member manufacturing apparatus in which a torus portion is formed in a central portion of the molded drum and cylindrical portions are formed on both sides of the torus portion.
Or
Said forming drum, further, by using the manufacturing apparatus of the rubber member having a concave peripheral groove in the vicinity of the boundary between the cylindrical portion and the torus portion,
It is a manufacturing method of pneumatic tires that manufactures pneumatic tires by the strip wind method.
Using the applicator, the rubber strip is conveyed to the molding drum, winding is started from one of the cylindrical portions, and after winding for a predetermined length, the rubber strip is wound.
The tip of the rubber strip is continuously wound around the torus portion, and the winding is completed at the other end of the cylindrical portion.
A pneumatic tire characterized in that the rolled rubber strip is cut at a boundary between the torus portion and the cylindrical portion, and the raw tire is formed by using the rubber strip wound around the torus portion. It is a manufacturing method of.

The invention according to claim 3
A method for manufacturing a pneumatic tire by a strip wind method using the rubber member manufacturing apparatus according to claim 1 .
Using the applicator, the rubber strip is conveyed to the molding drum, winding is started from one of the cylindrical portions, and after winding for a predetermined length, the rubber strip is wound.
The tip of the rubber strip is continuously wound around the torus portion, and the winding is completed at the other end of the cylindrical portion.
The rubber strip that has been wound is cut by a disk-shaped blade on the concave peripheral groove, and the rubber strip that is wound around the torus portion is used to form a raw tire. This is a tire manufacturing method.

The invention according to claim 4
3. The third aspect of the present invention is that the concave peripheral groove of the molding drum used in the rubber member manufacturing apparatus is formed with a groove width of 1/2 or less of the rubber strip width and a depth of 5 mm or more. The method for manufacturing a pneumatic tire according to the above.

The invention according to claim 5
The method for manufacturing a pneumatic tire according to any one of claims 2 to 4 , wherein the pneumatic tire to be manufactured is a tire for automobile racing.

According to the present invention, it is possible to provide 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 a rubber compounded as a rubber member of an automobile racing tire. it can.

It is an overall side view including a partial cross section of the rubber member manufacturing apparatus which concerns on one Embodiment of this invention. It is a perspective view which shows the molding drum which concerns on one Embodiment of this invention. It is sectional drawing which shows the main part in the state which the rubber strip was wound 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, the rubber member manufacturing apparatus 1 supplies a tape-shaped rubber strip GS made of unvulcanized rubber and winds it around the outer periphery of the 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 the molding drum 6. That is, FIG. 2 is a perspective view showing the molding drum 6, and the molding drum 6 is provided on both sides of the torus portion 6a and the torus portion 6a, which are provided in the central portion and whose diameter increases from both sides toward the central portion. It is provided with a pair of cylindrical portions 6b and 6c.

Then, 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, and then the tip of the rubber strip is wound around the torus portion 6a without stopping the extrusion of the rubber strip. It is completed by winding on the other cylindrical portion 6c.

As a result, the stop mark is formed on the cylindrical portions 6b and 6c, but not on the torus portion 6a. Then, the rubber strips that are wound at the boundary between the cylindrical portions 6b and 6c and the torus portion 6a are cut, and the raw tire is formed using only the rubber strip of the torus portion 6a, thereby being used for automobile racing tires. Even 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 it is possible 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 extrusion apparatus 2, a calendar head 3 arranged on the downstream side of the rubber extrusion direction X, and an applicator 5 provided on the downstream side of the calendar head 3. And a molding drum 6 provided on the downstream side of the applicator 5.

The rubber extrusion device 2 premolds and extrudes the put-in rubber G1. The rubber extruder main body 7, the gear pump 8 provided on the downstream side thereof, and the extrusion device provided on the downstream side of the gear pump 8 are extruded. It is equipped with a head 9.

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

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

The extrusion gear 8b is rotationally driven by an electric motor (not shown). As a result, the rubber G1 is filled between the tooth groove of the extrusion gear 8b and the casing 8a, and is quantitatively pumped from the outlet.

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

The calendar head 3 includes a pair of calendar rolls 3a and 3b arranged one above the other. Each of the calendar rolls 3a and 3b is configured to be rotationally driveable in opposite directions 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 at a predetermined calendar pressure.

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

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

That is, the tread compound used for automobile racing tires contains more oil than general tire compounds in order to realize high grip, and it is easy to cause changes in physical properties and is very sticky. This is because it is difficult to transport by festival because of its high characteristics.

Specifically, when measured with a tack meter, the adhesiveness of the race compound is 5.0 to 7.0, whereas that of the general compound is 1.0 to 3.0, so that it is a tire for automobile racing. This is because the festival cannot be used when strip-winding the tread, and if the control of the calendar head is changed, adhesion troubles may occur one after another.

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 is provided with a torus portion 6a provided in the central portion and having a diameter increasing from both sides toward the central portion, and a pair of cylindrical portions 6b and 6c 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.

In the molding drum 6, it is preferable that concave peripheral grooves 6d are continuously formed in the circumferential direction near the boundary between the torus portion 6a and the cylindrical portions 6b and 6c. The concave peripheral groove 6d has a groove width W1 of 1/2 or less, more preferably 1/3 to 1/5 of the rubber strip width W2, and 5 mm or more, more preferably. It is preferably formed at a depth H of 5 to 10 mm.

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

As shown in FIG. 1, the rubber molded body G2 extruded from the rubber extruder 2 is rolled by the calendar head 3. By this rolling, thin rubber strips GS having preset dimensions are 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 forming drum 6 by the conveyor 5a.

One end (tip) of the rubber strip GS is fixed to one cylindrical portion 6b 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 portion 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 up to a stable thickness.

In particular, the tread gauge of automobile racing tires is as thin as 4 mm or less, and if the rubber compounded for automobile racing is simply extruded by the gear pump method, a stop mark with a thickness of 3 to 4 mm will be formed, and the thickness will be nearly double locally. A part is created, which becomes the starting point of damage in the high-speed durability test of the tire. Therefore, by doing so as described above, a particularly remarkable effect is exhibited in the case of the rubber strip GS of the automobile tire.

If necessary, the forming drum 6 can be appropriately moved to change the winding pitch of the rubber strip GS and the like to form rubber members having various cross-sectional shapes.

Since the forming drum 6 has a peripheral groove 6d near the boundary between the torus portion 6a and the cylindrical portions 6b and 6c, the peripheral groove 6d is cut by the disk-shaped blade 11 after the rubber strip GS winding is completed. 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 the tire member. After that, the pneumatic tire is manufactured by the existing device.

As described above, according to the rubber strip manufacturing apparatus and the pneumatic tire manufacturing method of the present embodiment, unlike the conventional one, even a very sticky compound which could not be adopted in the past is suitable. Since it can be used, the stop mark is not formed even in the strip wind method using the rubber compounded as the rubber member of the tire for automobile racing.

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

1. 1. Preparation of Specimen A rubber strip having a width shown in Table 1 was wound on a molding drum to form a raw tire, and then vulcanized to produce 10 race tires having a tire size of 300 / 680R18SLICK.

The tack of the rubber strip used was a tack meter manufactured by Toyo Seiki, and the crimping load was 4.9 N, the peeling speed was 10 mm / min, and the standard sample size was 12.7 mm × in accordance with JIS T 9233. When measured under the conditions of 152 mm and crimping time: 10 seconds, it was 7.0.

(1) Example 1
Using a molded drum provided with cylindrical parts with a diameter of 648 mm and a length of 100 mm on both sides of a torus part with a maximum diameter of 688 mm and a width of 318 mm, after winding 4 m on one of the cylindrical parts, the torus part The tires are wound 120 m so as to overlap at a pitch of 6 mm, the winding is completed with the other cylindrical portion as the end portion, and as shown in FIG. 3, a disk-shaped blade having a diameter of 100 mm is used to cut on both sides of the torus portion. Was used as a tread member to form a raw tire.

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

(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. 2. Evaluation (1) Presence or absence of cut defects and stop marks The presence or absence of cut defects and stop marks in the molding process of raw tires was visually observed.

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

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

From Table 1, in Comparative Example 1, the stop mark that existed at a point 2.5 m after extrusion remained even after the raw tire was molded, whereas in Examples 1 to 1, a cylindrical portion was provided on the molding drum. It can be seen that the stop mark disappears in 5. Further, it can be seen that the high-speed durability was incompatible in Comparative Example 1, whereas it was incompatible in Examples 1 to 5.

Then, in Examples 1, 2 and 5, cutting defects occurred, but in Example 3 in which a groove width of 1/2 or less of the rubber strip width and a concave peripheral groove were formed at a depth of 5 mm or more. It can be seen that in No. 4, there is no occurrence of cut defects.

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

1 Rubber member manufacturing equipment 2 Rubber extrusion equipment 3 Calendar head 3a, 3b Calender roll 5 Applicator 5a Conveyor 6 Molding drum 6a Taurus part 6b, 6c Cylindrical part 6d Circumferential groove 7 Rubber extruder body 7a Cylinder 7b Screw shaft 7c Rubber Input 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 molded body GS Rubber strip H Depth J Discharge port W1 Groove width W2 Rubber strip width X Rubber extrusion direction

Claims (5)

A rubber member manufacturing device that continuously winds rubber strips continuously extruded from a rubber extruder onto 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 an extruder having a gear pump connected to a discharge port of the extruder main body.
A calendar head that processes a rubber strip extruded from the extruder into a predetermined cross-sectional shape, and
It is provided with an applicator that receives the rubber strip from the calendar head, conveys it to the molding drum, and winds it for a predetermined length.
The molded drum has a torus portion formed in the center portion, and cylindrical portions are formed on both sides of the torus portion .
An apparatus for manufacturing a rubber member, wherein the molded drum has a concave peripheral groove near the boundary between the torus portion and the cylindrical portion. A rubber member manufacturing device that continuously winds rubber strips continuously extruded from a rubber extruder onto 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 an extruder having a gear pump connected to a discharge port of the extruder main body.
A calendar head that processes a rubber strip extruded from the extruder into a predetermined cross-sectional shape, and
It is provided with an applicator that receives the rubber strip from the calendar head, conveys it to the molding drum, and winds it for a predetermined length.
A rubber member manufacturing apparatus in which a torus portion is formed in a central portion of the molded drum and cylindrical portions are formed on both sides of the torus portion.
Or
Said forming drum, further, by using the manufacturing apparatus of the rubber member having a concave peripheral groove in the vicinity of the boundary between the cylindrical portion and the torus portion,
It is a manufacturing method of pneumatic tires that manufactures pneumatic tires by the strip wind method.
Using the applicator, the rubber strip is conveyed to the molding drum, winding is started from one of the cylindrical portions, and after winding for a predetermined length, the rubber strip is wound.
The tip of the rubber strip is continuously wound around the torus portion, and the winding is completed at the other end of the cylindrical portion.
A pneumatic tire characterized in that the rolled rubber strip is cut at a boundary between the torus portion and the cylindrical portion, and the raw tire is formed by using the rubber strip wound around the torus portion. Manufacturing method. A method for manufacturing a pneumatic tire by a strip wind method using the rubber member manufacturing apparatus according to claim 1 .
Using the applicator, the rubber strip is conveyed to the molding drum, winding is started from one of the cylindrical portions, and after winding for a predetermined length, the rubber strip is wound.
The tip of the rubber strip is continuously wound around the torus portion, and the winding is completed at the other end of the cylindrical portion.
The rubber strip that has been wound is cut by a disk-shaped blade on the concave peripheral groove, and the rubber strip that is wound around the torus portion is used to form a raw tire. How to make tires. 3. The third aspect of the present invention is that the concave peripheral groove of the molding drum used in the rubber member manufacturing apparatus is formed with a groove width of 1/2 or less of the rubber strip width and a depth of 5 mm or more. The method for manufacturing a pneumatic tire described in. The method for manufacturing a pneumatic tire according to any one of claims 2 to 4 , wherein the pneumatic tire to be manufactured is a tire for automobile racing.

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