Manufacturing method of rubber member for tire

Abstract

The invention can reduce a step between rubber strips even in the case that the rubber strip is made thick, and inhibits a reduction of uniformity and tire quality, a deterioration of a tire outer appearance, and the like. A rubber strip ( 10 ) may be scalene triangular shape, a trapezoidal shape or a parallelogram shape having has a bottom line ( 11 ) forming a strip width (W), a first diagonal line ( 12 ) extending from one end of the bottom line ( 11 ) and a second diagonal line ( 13 ) extending from the other end (P 2 ) of the bottom line ( 11 ), a length (L 0 ) of the bottom line is set to 5 to 50 mm, and a thickness (T) thereof is set to 0.2 to 5.0 mm.

1 . A method for forming a rubber member by overlapping and winding at least one rubber strip in a circumferential direction and in a spiral shape, 
     wherein
 said at least one rubber strip has a thickness T in a range of from 0.2 to 5.0 mm, and a cross sectional shape defined by a bottom line, a first diagonal line extending from one end of the bottom line, a second diagonal line extending from the other end of the bottom line, and an upper line parallel to the bottom line, 
 
     wherein
 the bottom line has a length (L 0 ) in a range of from 5 to 50 mm, 
 the angle between the first diagonal line and the bottom line is in a range of more than 45 degrees but not more than 80 degrees, 
 the angle between the second diagonal line and the bottom line is in a range of more than 45 degree but not more than 80 degrees to form the trapezoidal cross sectional shape, or alternatively, in a range of not less than 100 but less than 135 degrees to form the parallelogram cross sectional shape, 
 
   
   
       2 . The method according to  claim 1 , wherein
 the windings of said at least one rubber strip are overlapped such that the width (Wj) of overlap between the adjacent windings is in a range of from 0.8 to 1.2 times the average (L) of the length (La) of the first diagonal line and the length (Lb) of the second diagonal line, when measured along the direction of the bottom line.   
   
   
       3 . The method according to  claim 1  or  2 , wherein
 the apexes of the cross sectional shape are each chamfered by a circular arc having a radius in a range of from 0.2 to 1.0 mm.   
   
   
       4 . The method according to  claim 1  or  2 , wherein
 the apexes of the cross sectional shape are each chamfered by a circular arc having a radius in a range of from 0.2 to 1.0 mm, and   said thickness T is in a range of from 4.0 to 5.0 mm.   
   
   
       5 . The method according to  claim 1 , wherein
 said at least one rubber strip is two strips each having the trapezoidal cross sectional shape, and   one of the two strips is wound, forming a gap between the adjacent windings, and   the other strip is wound along the gap, turning the bottom line to the opposite direction to that of the one strip.   
   
   
       6 . The method according to  claim 2 , wherein
 said at least one rubber strip has the parallelogram cross sectional shape.   
   
   
       7 . The method according to  claim 1 , wherein
 said at least one rubber strip has the parallelogram cross sectional shape, and   the windings of said at least one rubber strip are overlapped such that the bottom line of one of the adjacent two windings overlaps the upper line of the other.   
   
   
       8 . A method for manufacturing a pneumatic tire formed from a plurality of rubber members which include a tread rubber disposed in the tread portion to form the ground contacting surface, a sidewall rubber disposed in the sidewall portion to form an outer surface thereof, a clinch rubber disposed in the bead portion to form an outer surface thereof, and an inner liner rubber disposed inside a carcass to form an inner surface of the tire, the method comprising the steps of:
 forming at least one of the rubber members through the method set forth in  claim 1 ,  2 ,  5 ,  6  or  7 ,   forming an unvulcanized tire by using the rubber members, and   vulcanizing the tire.   
   
   
       9 . A method for manufacturing a pneumatic tire formed from a plurality of rubber members which include a tread rubber disposed in the tread portion to form the ground contacting surface, a sidewall rubber disposed in the sidewall portion to form an outer surface thereof, a clinch rubber disposed in the bead portion to form an outer surface thereof, and an inner liner rubber disposed inside a carcass to form an inner surface of the tire, the method comprising the steps of:
 forming at least one of the rubber members through the method set forth in  claim 3 ,   forming an unvulcanized tire by using the rubber members, and   vulcanizing the tire.   
   
   
       10 . method for manufacturing a pneumatic tire formed from a plurality of rubber members which include a tread rubber disposed in the tread portion to form the ground contacting surface, a sidewall rubber disposed in the sidewall portion to form an outer surface thereof, a clinch rubber disposed in the bead portion to form an outer surface thereof, and an inner liner rubber disposed inside a carcass to form an inner surface of the tire, the method comprising the steps of:
 forming at least one of the rubber members through the method set forth in  claim 4     forming an unvulcanized tire by using the rubber members, and   vulcanizing the tire.