US 4,216,809 AGranted

Pneumatic tire having a run-flat insert structure

AssigneeUniroyal, Inc.

InventorJames J. Pixley

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Abstract

A run-flat insert structure for a pneumatic tire is disclosed in which the insert structure comprises a homogeneous elastomeric material and is fully enclosed and pneumatically inflated. The insert structure is mounted within the cavity formed by the pneumatic tire and the wheel rim upon which the tire is mounted. The insert structure is shaped and spaced from the interior walls of the tire such that contact between the insert structure and the interior tire walls is minimized during rated load carrying and inflation conditions of the tire. The volume of the insert structure is less than 50% of the volume of the cavity formed by the tire and the wheel rim to thereby assist in avoiding undesirable contact between the insert structure and the tire. During the deflated condition of the tire, the insert structure supports the tire and its load at a deflection that prevents excessively rapid deterioration of the tire while running in the deflated, run-flat condition.

In combination with a pneumatic tire and a wheel rim upon which the tire is supported, said wheel rim having an annular support surface extending laterally in the direction of the axis of the wheel rim and a pair of axially spaced apart annular flanges each connected to and extending radially outward from said annular support surface, the distance between said radially extending annular flanges being the rim width of the wheel rim, said tire having a pair of axially spaced annular beads each in engagement with one of said flanges and the support surface, a pair of sidewalls each connected to and extending generally radially outward from the beads, and a tread connected to the radially outward ends of the sidewalls, said tire and wheel rim forming a closed toroidal cavity:

a generally toroidal shaped, hollow, inflatable insert disposed within said cavity and bearing against said support surface of the wheel rim and having a pair of lateral walls each in engagement with one of the bead regions of the tire, said insert having an interior volume of less than 50% of the volume of said cavity;
and
each lateral wall has a radially inward annular wall portion which, in cross section, is concave in the direction of the interior of the insert and a radially outward annular wall portion which, in cross section, is concave in the direction of the exterior of the insert, said radially inward and radially outward annular wall portions being joined together along a circumferential edge between their respective opposed concavities, said circumferential edge projecting a corner in the cross section of said lateral wall, said corner of each lateral wall being located at a distance radially outward of the most radially inward part of the bead region such that the contact of said radially inward annular wall portion with the tire does not extend in a laterally outward direction beyond the rim width, and the radially inward annular wall portions are the only wall portions of the lateral walls in engagement with the tire.

Abstract

Claims2