Bridgestone Corporation

Tomohiro Irie

Yukio Saegusa

Tetsuo Tsujimoto

Noriaki Kurabayashi

A tire molding machine includes a pair of bead core supporting devices for holding respective bead cores, which are arranged on radially outer side of a carcass band, so that the bead core has a center axis with a controllable inclination angle. The bead core supporting device (), which controls the inclination angle of the bead core center axis, includes an annular upright plate), a bead holder ring () secured to the annular upright plate, for holding the bead core (B) in parallel manner, and bead holder ring posture control means () for controlling the inclination angle of the center axis of the bead holder ring relative to the center axis of the annular upright plate, within an angular range including zero degree.

Tire molding machine

In a tire molding process, a mutual positional deviation or angular deviation between the axis of a carcass member and the axis of a bead core takes place in a produced tire when the bead core is set on the outer periphery of cylindrical carcass member. By the use of an estimation formula for estimating the primary harmonic component in the waveform of a radial force, an inverse waveform with the primary harmonic component inversed is found with respect to the measurement waveform of the produced tire or with respect to the treatment waveform with a numerical value treatment applied thereto. Thereafter, in producing a tire of the same size by the mold used for producing the preceding tire, the mutual positional deviation or angular deviation between the axis of the carcass member and the axis of the bead core found by a backward calculation from the estimation formula is changed to set the bead core on the carcass member.

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Tokyo, Japan

Tomohiro Irie