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Review of PV for Plain Polymer Bearings


In this article, we are going to review some of the basic principles behind the PV value, and take a look at some PV values for commonly used bearing materials.

polymer-bushings-PEEK-Nylon-Torlon.jpg

Introduction

The amount of wear a bearing is going to experience is related to the bearing pressure and the running velocity.  The more pressure applied to the bearing, the faster it will wear; similarly, the faster the bearing surface speed, the more wear will occur.  Did you ever wonder why?  One clue lies in the amount of heat that is generated as a result of interaction between the bearing and the shaft.  The more heat that is generated, the faster the bearing will wear.  One value that represents this relationship between heat generated and the resulting wear is the PV value.  You will see this value used as a key part of the material selection process when specifying a bearing.

Here are some other articles on Polymer Bushings and Bearings from Advanced EMC Technologies Blog:

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Four Most Popular Rotary Shaft Seals Material Options and How They Compare


Evolution of Seal Materials

The evolution of seal materials evolved as seals faced more rugged demands.  Early needs could be met using packed hemp or leather, but as the demands became more and more rigorous new materials were sought.  This led to the introduction of natural rubber seals, which evolved into synthetic elastomers, and finally engineering polymers like PTFE (Polytetrafluoroethylene).

PTFE-Nylon-Rubber-FKM-_seal_materials.jpg

Four of the most common modern material options for rotary shaft seal lips are nitrile rubber, polyacrylate, FKM, and PTFE.  Of these materials, three are elastomers – nitrile rubber, polyacrylate rubber and FKM – and only one is polymer – PTFE.  Let’s see how these materials stack up.

 

Want more about PTFE? Check out these artiicles from the popular Advanced EMC Technologies blog:

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