JPH08216290A - Manufacture of pneumatic tire - Google Patents

Abstract

PURPOSE: To provide a method for manufacture of a tread which is free from irregularities at both end parts by a method wherein a rubber sheet of a required cut width having no dispersion is supplied to a rubber roll and wound on a crown part of a tire carcass. CONSTITUTION: In a method for manufacture of a tire wherein an un-vulcanized rubber sheet is successively wound on a crown part of a tire carcass to be laminated and a tread is formed thereby, a sheet supply roll G which comes in contact with a transfer rubber roll F lining a rubber sheet S on the tire carcass T, and is revolved at the same speed as that of the transfer rubber roll F, is provided. The rubber sheet S rolled in a sheet shape on the sheet supply roll G is cut to a required width, and supplied to the transfer rubber roll F.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a pneumatic tire, and more particularly to a method for manufacturing a tread by laminating a green sheet on the crown portion of a tire carcass.

[0002]

2. Description of the Related Art Generally, a green tread, which is one of intermediate members constituting a tire, is an extruder for extruding a kneaded rubber obtained by mixing natural or synthetic rubber with a rubber compounding agent such as a vulcanizing agent and a filler. It is manufactured by extruding from a tread base into a desired shape. However, treads used for the production of large or very large tires, such as tires for construction vehicles, exceed the limit capacity of the extruder, are inefficient in energy, or are small or lightweight intermediate members. For the reason that it is required to reduce the labor due to the above, a tread having a desired cross-sectional shape may be formed by sequentially winding and laminating a sheet-shaped rubber on a green carcass. Also, in a small-scale tire production plant that does not have sufficient extrusion capacity, the method of forming a tread by the above-mentioned sheet lamination method may be adopted even for tires for passenger cars, trucks, buses, etc. is there. like this,
A tread that is molded into a desired cross-sectional shape by sequentially winding and stacking sheet-shaped rubber on a green carcass is called a laminated tread or a laminated tread. Distinguished from an integral tread that is extruded to the desired cross-sectional shape. The cross-sectional shape of the tread may be referred to as a tread contour or simply contour.

In the laminated tread method, a sheet-shaped rubber is sequentially wound and laminated on the green carcass while changing the width of the rubber sheet for each winding, and a desired contour (section shape) is obtained. The tread is molded. Conventionally, as shown in FIG. 2, a kneaded rubber is rolled into a sheet by a pair of seating rolls (A, B), and a rubber sheet required for each winding of the tire on the seating roll. The rubber at both ends is cut to the width of the sheet, and the unnecessary rubber at both ends is returned to the sheeting roll (A, B), while the continuous rubber sheets cut to the desired width are separated. Is fed to a transfer rubber roll (F) through a plurality of transport rolls (C, D, E) provided with the rubber sheet on the crown portion of the tire carcass. The laminated tread is molded by being sequentially pressed and wound.

[0004]

Conventionally, since the laminated tread is molded in this manner, the sheeting
A plurality of conveying rolls (C, D, C) provided with continuous rubber sheets cut at a desired width on the rolls at intervals.
While being fed to the transfer rubber roll (F) via E), the rubber sheet meanders and expands and contracts, especially when floating in the air between the rolls, and the transfer rubber roll
When the roll (F) is wound around the crown portion of the tire carcass, the width of the rubber sheet is different from the desired width, in other words, the width of the rubber sheet varies. ing. as a result,
As shown in FIG. 3, unevenness is generated at both ends of the unvulcanized laminated tread formed by being wound while being sequentially pressure-bonded on the crown portion of the tire / carcass, and between the tire sheets after vulcanization. The appearance may be poor due to the difference in color tone or peeling between sheets, and it may lead to product defects due to bareness.
Further, in the worst case, not only the appearance is poor but also separation failure occurs due to peeling between sheets after running the tire.

The object of the present invention is to solve the above-mentioned drawbacks of the prior art, to supply a rubber sheet having a desired cutting width without variation to a transfer rubber roll and wind it around a crown portion of a tire carcass. It is to provide a method for manufacturing a tread having no irregularities on both ends.

[0006]

In order to achieve the above object, in the method of manufacturing a pneumatic tire according to the present invention, an unvulcanized rubber sheet is sequentially wound around a crown portion of a tire carcass and laminated. In the method for manufacturing a tire in which a tread is molded by: (1) providing a sheet feeding roll that is in contact with a transfer rubber roll that sticks the rubber sheet to a tire carcass and that rotates at the same speed as the transfer rubber roll; (2) A method of manufacturing a pneumatic tire, characterized in that a rubber sheet rolled into a sheet on the sheet supply roll is cut into a desired width and supplied to the transfer rubber roll.

[0007]

In the method of manufacturing a pneumatic tire according to the present invention,
In a method of manufacturing a tire, in which an unvulcanized rubber sheet is sequentially wound around the crown portion of a tire carcass and laminated to form a tread, (1) contacting a transfer rubber roll at the same speed as the transfer rubber roll Is provided with a sheet supply roll that rotates in (2), the rubber sheet rolled into a sheet is cut into a desired width on the sheet supply roll, and is supplied to the transfer rubber roll,
(3) Since the rubber sheet is wound around the crown portion of the tire carcass by the transfer rubber roll as it is, the rubber sheet after cutting to the desired width to be attached to the tire carcass is placed in the air between the rolls. Since the floating state does not occur, the rubber sheet does not meander or expand and contract, the width of the rubber sheet does not vary, and the rubber sheet cut to the desired width is transferred by the transfer rubber roll. It is possible to manufacture a tire wound around the crown portion of a tire / carcass and provided with treads having no irregularities at both ends.

[0008]

EXAMPLE An example according to the present invention will be described with reference to the drawings. In the method for manufacturing a tire having a laminated tread according to the present invention shown in FIG. 1, a pair of sheeting sheets made of kneaded rubber (R) is used. It is rolled into a sheet by rolls (A, B), reaches a sheet supply roll (G) through a plurality of conveying rolls (C, D, E) provided at intervals, and then reaches a desired width. That is, a continuous rubber sheet (S) in which the rubber at both ends is cut so that the width of the rubber sheet is required for each winding of the tire is the transfer rubber.
The laminated tread is formed by being supplied to a roll (F) and wound around the crown portion of the tire carcass (T) while being sequentially pressed by the transfer rubber roll (F). In this example, the tire size is 21.0.
At 0-35, the thickness of the sheet rubber is 4 mm.

In the above embodiment, the rubber at both ends is cut so that the width of the rubber sheet is required for each winding of the tire, and the width of the rubber sheet is set in a so-called stepwise manner. It is also possible to set the width of the rubber sheet steplessly according to the contour (cross-sectional shape) of the laminated tread.

For comparison with the above-described embodiment according to the present invention, a conventional example will be described with reference to the drawings. In the method for manufacturing a tire having a laminated tread according to the conventional example shown in FIG. 2, kneaded rubber is kneaded. (R) is rolled into a sheet by a pair of seating rolls (A, B), and the width of the rubber sheet on each of the seating rolls (B) is adjusted so that the width of the rubber sheet is required for each winding of the tire. The rubber was cut, and the unnecessary rubber at both ends was returned to the sheeting rolls (A, B), while continuous rubber sheets (S) cut to a desired width were provided at intervals. It is supplied to the transfer rubber roll (F) via a plurality of transport rolls (C, D, E), and the transfer rubber roll (F) sequentially press-bonds the rubber sheet to the crown portion of the tire carcass (T). Naga Wound and laminated tread is molded. Similar to the example, tire size is 2
At 1.00-35, the thickness of the sheet rubber is 4 mm.

Comparing the vulcanized tires manufactured according to the above-described embodiment of the present invention and the method according to the conventional example, the tire manufactured according to the method according to the conventional example has a difference in color tone between the sheets and peeling between the sheets. Although there were some appearance defects, the tires manufactured according to the method according to the examples did not show any appearance defects. Next, the tires manufactured according to the methods according to the above-mentioned examples and conventional examples were put into an actual vehicle test and evaluated under the same conditions. The number of test tires is 10 each. In the tire manufactured according to the method according to the conventional example, cracks (separation between sheets) having a depth of about 1 to 2 mm occurred at several places on the circumference at both ends of the tread of two of the ten tires. No crack was generated in the tire manufactured according to the method described in 1.

[0012]

The present invention provides a method for producing a tread in which a rubber sheet having a desired cutting width without variation is supplied to a transfer rubber roll and wound around the crown portion of a tire carcass so that both ends thereof have no unevenness. It became possible to do.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a method for manufacturing a tire provided with a laminated tread according to the present invention.

FIG. 2 is a conceptual diagram showing a method of manufacturing a tire having a conventional laminated tread.

FIG. 3 is a schematic sectional view of a tire including a conventional laminated tread.

[Explanation of symbols]

 A seating roll B seating roll C transport roll D transport roll E transport roll F transfer rubber roll G sheet supply roll R kneaded rubber S rubber sheet T tire carcass

Claims (1)

[Claims] 1. A method of manufacturing a tire, wherein a tread is formed by sequentially winding and stacking an unvulcanized rubber sheet on a crown portion of a tire carcass.
(1) A sheet supply roll that comes into contact with a transfer rubber roll that adheres the rubber sheet to a tire carcass and rotates at the same speed as the transfer rubber roll is provided, and (2) a sheet is placed on the sheet supply roll. A method for producing a pneumatic tire, which comprises cutting a rubber sheet rolled into a sheet into a desired width and supplying the cut rubber sheet to the transfer rubber roll.