Rigid cores for tire formation

Abstract

The present invention provides a rigid core for forming a tire, which can not only maintain the air release performance, but also suppress the inflow of rubber into the air release groove. The core body includes a plurality of core segments divided in the circumferential direction, and at least one joint surface of the adjacent core segments in the circumferential direction is provided with a vent groove, and the vent groove has tires on the core body side. The open end of the molding face opening. The venting grooves include tread venting grooves whose opening ends are opened on the tread forming surface on the core side, and / or sidewall venting grooves which are opened on the sidewall forming surface on the core side. The tread vent groove has an inclined groove portion extending obliquely at an angle θ1 from an open end with respect to the tire radial direction line, and the side vent groove has an inclined groove portion extending from the tire radial direction line. The open end extends obliquely at an angle θ2 with respect to the tire axial line.

Description

technical field [0001] The present invention relates to a rigid core for tire formation in which a vent groove is formed on a joint surface of a core segment. Background technique [0002] In recent years, in order to improve the forming accuracy of a tire, a tire forming method (hereinafter, sometimes referred to as a core processing method) using a rigid core has been proposed (for example, refer to Patent Documents 1 and 2). The rigid core is provided with a core body having an outer shape conforming to the shape of the tire inner cavity surface of the tire after vulcanization. Then, a green tire is formed by sequentially attaching tire constituent members to the core body. The green tire is placed in a vulcanization mold together with a rigid core, whereby the green tire is vulcanized and molded by sandwiching the green tire between a core body serving as an inner mold and a vulcanizing mold serving as an outer mold. [0003] like Figure 7 As shown in (A), in order to...

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Problems solved by technology

However, in this case, there is a problem that the strength of the connecting portion becomes insufficient due to repeated large-scale thermal expansion, and the durability of the core segment decreases.

In addition, the above scheme still does not consider the problem of rubber flowing into the exhaust passage

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