Browse Prior Art Database

REVERSE CYCLIC DYNAMIC OZONE FATIGUE TESTING FOR TIRE VALVE STEMS

IP.com Disclosure Number: IPCOM000234044D
Publication Date: 2014-Jan-08
Document File: 1 page(s) / 75K

Publishing Venue

The IP.com Prior Art Database

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 66% of the total text.

Page 01 of 1

REVERSE CYCLIC DYNAMIC OZONE FATIGUE TESTING FOR TIRE VALVE STEMS

A means was needed for evaluating the ozone resistance of various rubber formulations that are used for tire valve stem applications. Current industry standard ozone testing of valve stems involves holding a statically deflected valve stem in an ozone rich environment for a period of time (typically 72 hours). This is followed by visual inspection of the valve stem rubber for cracks. The presence of cracks indicates a general lack of ozone resistance in the rubber formulation. However, vehicle mounted valve stems do not remain statically positioned on the wheel. When the vehicle accelerates, the valve stems deflect away from the neutral position. As the vehicle slows, the valve stems return to their neutral position. The current industry standard test methods do not capture this dynamic deflection during the environmental exposure. We needed a way to duplicate this cyclic deflection field condition in the laboratory.

Method

Combining the elements of three industry standard test methods, we were able to create a test that measured the fatigue life of tire valve stems that were subjected to reverse bending cyclic fatigue testing in an ozone rich atmosphere.

 SAE J1206, Section 4.7, was used as the heat age preconditioning for the valve stems that were to be subjected to subsequent dynamic ozone fatigue testing.

 ASTM D1149, Method A, Procedure A1, was used to create the dynamic ozone apparatus...