Truck tyre

Abstract

A truck tyre comprises the following components: a tyre body card fabric layer which is provided with a pair of card fabric layer reverse-packaging parts and a main body part of card fabric layer between the card fabric layer reverse-packaging parts; a tyre bead apex which is installed between the main body part of card fabric layer and each card fabric layer reverse-packaging part; a tyre bead reinforcing layer; and a clamping rubber which is positioned at the axial external side of the tyre bead reinforcing layer. The tyre bead apex comprises a high-modulus inner part and a low-modulus external part, wherein the interface between the inner part and the outer part extends from the main body part of card fabric layer to the card fabric layer reverse-packaging parts. The height HPi of the axial inner part of the tyre bead reinforcing layer is larger than the height HN of the tyre body card fabric layer reverse-packaging parts. The height HEi of the inner part of the apex is larger thanthe height HPi of axial inner part of the tyre bead reinforcing layer. The thickness T2i of the inner part of the apex, which is measured along a second measuring line X2, is 10%-25% of the maximum width Wc measured along the axial direction of the tyre. The thickness T2o of the outer part of the apex, which is measured along the second measuring line X2, is 70%-100% of the whole rubber thicknessT1 of the tyre bead apex measured along a first measuring line X1.

Description

truck tire technical field The present invention relates to a pneumatic tire, and more particularly to a bead structure suitable for a truck tire capable of improving bead durability. Background technique In the case of a truck tire such as a truck / bus tire, as shown in FIG. ply b, therefore there is a tendency to cause damage such as carcass cord loosening and ply edge delamination at the radially outer end b1e of the carcass ply turnup b1 under severe service conditions. Therefore, the bead portion c is generally provided with a bead reinforcing layer d made of steel cords, for example, as disclosed in Japanese Patent Application Laid-Open (KOKAI) No. 55-106807. The main function of the bead reinforcing layer d is to increase the bead stiffness and thereby reduce bead deformation. If the axially inner portion d2 of the bead reinforcing layer d extending along the main body portion b2 of the carcass ply b exceeds the radially outer end b1e of the turnup portion b1 in ...

AI Technical Summary

Problems solved by technology

Thus, the tire is also susceptible to damage due to the stress concentration on the outer end d2e

On the other hand, if the axially outer portion d1 of the bead reinforcing layer d extending along the turnup b1 of the carcass ply b exceeds the radially outer end b1e of the turnup b1 in radial height, then when When the bead portion is deformed, the axially outer portion d1 is subjected to a large compressive strain, so it is easily damaged

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