| 摘要 |
PURPOSE:To enable to suppress the lowering of the physical properties of rubber and at the same time to shorten the vulcanizing time by a method wherein, as for the crude rubber to fill a cavity made by removing the damaged portion, the farther a layer, which is one of a plurality of layers made by dividing the cavity in the direction of its depth, lies from heaters, the higher the curing speed of the crude rubber, which is to be filled in said layers, is. CONSTITUTION:Firstly, the damaged portion, which is developed at the tread portion 2 of a pneumatic tire so as to pierce a belt 3 and a carcass 4, is removed by being shaved off so as to form a nearly columnar through cavity 5. Secondly, cement is applied onto the cavity and cushioning rubber is arranged so as to cover the cored portions of the belt 3 and of the carcass 4 in order to enhance the bonding effect. Thirdly, crude rubber sheets 6 are packed one after another while being fixed by pressure in said cavity 5. The crude rubber 6 is divided into three layers in the direction of the depth of the cavity 5 and the crude rubbers 6a and 6b which have the lower curing speed are packed into the inner and the outer layers, while the crude rubber 6c which has the higher curing speed, is packed into the middle layer. At the finish of vulcanization, the degrees of cure of the crude rubbers 6a and 6b becomes nearly equal to that of the crude rubber 6c and consequently the degrees of overcurring of the crude rubbers 6a and 6b become small.
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