Bridgestone/firestone, Inc.

David C Christy

Neel K Mani

Stanley J Olesky

Martin A Yurjevich

John D Clothiaux

John G Lightner

Karl J Neimes

Larry L Schlabaugh

A friction testing machine and method for measuring friction characteristics between a test sample and a friction surface. The machine and method are particularly suited for measuring the coefficient of friction between a rubber specimen or a tread element and different friction surfaces at different sliding velocities, contact pressures and orientations. A preferred embodiment of machine is self-contained and portable, configured for easy and quick changing of the friction surface, and provides for rotating the test sample about an axis normal to the sliding surface and the direction of movement of the sample relative to the friction surface. In general, a friction test machine according to the invention comprises a sample holder configured to hold a sample in frictional engagement with a friction surface, and a motion device for effecting relative movement between the friction surface and sample holder in a first direction. Also provided is a variable weight loading device on the sample holder for loading the sample holder such that a selected load can be applied to the sample normal to the friction surface, and a force measurement device for obtaining a measurement indicative of the frictional force resisting such relative movement between the sample holder and the friction surface effected by the motion device.

Portable universal friction testing machine and method

A method of testing a tire for rain groove wander is provided which allows a tire to be objectively tested in a laboratory wherein the objective test results closely correlate with subjective field analysis type data, thereby allowing for the subjective tire performance to be predicted while precluding the need for subjective field analysis of the particular tire. The method also allows objective testing of a single tire size by varying the radial loading in the laboratory test set, thereby precluding the construction of multiple tire sizes each having the same tread design. The method simulates rain groove road conditions and correlates objective analysis data obtained via the laboratory test methodology with subjective field analysis data of rain groove wander tire performance of other tires, thereby providing a substantially accurate technique for identifying the subjective performance of the tire without having to conduct the field testing to obtain such subjective field analysis data. The method substantially reduces the cost required is to design and test a prototype tire design and the time required to implement tire design testing.

Method for predicting tire performance on rain groove roadways

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Akron, OH, United States of America

David C Christy