Patent ID: 7238249
Filing Date: 2007-07-03
Classification: B29D

Abstract:
1. A producing method of a high speed FV reducing tire in which a variation amount of a total gage of a tread portion of each of non-vulcanized raw tires Pi (i=1 to m) each having a plurality of(k) tire constituent members including a joint portion whose one end and the other end in its circumferential direction are connected to each other, and a high speed FV of each of completed tires Qi (i=1 to m) obtained by vulcanizing and forming the raw tire Pi (i=1 to m) using a vulcanization mold are measured to obtain an estimation equation, and an n-order component of high speed FV of completed tires after m-th completed tire is reduced by specifying a mounting phase of each of raw tires after m-th raw tire with respect to the vulcanization mold based on the estimation equation, wherein the method comprises: 1) a step of measuring a total gage of a tread portion of each of a number m of the raw tires Pi (i=1 to m), where m is ten or more in the same lot, and using said measured total gage to obtain a joint variation vector (→Jij) comprising a local joint variation amount Jij (i=1 to m and j=1 to k) of the total gage in the joint portion (j=1 to k) of each of the tire constituent members and a phase θij of each joint positions from a raw tire reference position X 2) a step of obtaining a distribution of the variation amount of said measured total gage over one circuit of the tire while using the raw tire reference position X 3) a step of measuring the high speed FV of each of the completed tires Qi(i=1 to m), performing order-analysis on a distribution of the variation amount of the high speed FV over one circuit of the tire while using the raw tire reference position X 4) a step of obtaining a mold n-order component vector (→MFVn) of high speed FV generated due to the vulcanization mold using the high speed FV n-order component vector (→QFVin) of each the completed tire Qi, 5) a step of subtracting the high speed FV mold n-order component vector (→MFVn) from the high speed FV n-order component vector (→QFVin) of each the completed tire Qi, thereby obtaining a high speed FV n-order component vector (→PFVin) of the raw tire Pi corresponding to each the completed tire Qi using the following equation 1): 6) a step of obtaining transfer functions→An,→Bnj (j=1 to k) in the following multiple regression estimation equation 2) by least squares method using the vectors (→QFVin), (→MFVn), (→Vin) and (→Jij) of the in-number tires obtained in steps 1) to 4), thereby completing the estimation equation 2), 7) a step of obtaining the joint variation vector (→Jij) and the total gage n-order component vector (→Vin) of each of raw tire Pi (i>m) after the m-th raw tire, and, by substituting the same into the estimation equation 2), estimating the high speed FV n-order component vector (→PFVin) of each of the raw tires Pi (i>m) after the m-th raw tire, and 8) a step of mounting each of the raw tires Pi (i>m) after the m-th raw tire to a vulcanization mold at a relative phase α of a mold reference position X