PV is the product of projected pressure and sliding speed. Plain-bearing manufacturers use it as a screening measure related to frictional heat and operating severity. This reference lists three igus polymer materials and the manufacturer maximum dry PV values shown on their material pages. Those numbers apply only to the cited product and stated test configuration. They are not generic limits for every sintered or polymer bushing, and a value below the listed maximum does not establish a predicted service life.

Sintered and Polymer Bearing PV Limits

Use the conditions with the number

The cited material pages describe dry running against a steel shaft at 68°F, in a steel housing, and with specified bushing wall thickness. The iglide P page, for example, limits the permitted PV curve to a bushing with a 0.039 inch wall and explains the maximum is reached only at very low pressure. A different shaft finish, housing, wall thickness, temperature, lubricant, motion pattern, or duty cycle can change performance. Keep each value attached to its exact product page instead of ranking materials by one isolated number.

Worked PV calculation

Suppose a preliminary estimate gives 30 psi projected pressure and 100 ft/min sliding speed. The arithmetic PV is 30×100=3,000 psi·ft/min. That is below the displayed maximum for the listed iglide P material, but the comparison is only a first screen. It does not prove that the chosen bushing has an adequate wear life or that the condition lies within the relevant manufacturer curve. Confirm the actual pressure distribution, shaft material and finish, operating temperature, and product-specific application chart before selecting the component.

Pressure, speed, and motion matter separately

Two combinations can have the same PV product and still behave differently. A high pressure with low speed can produce different deformation and wear from low pressure with high speed. Oscillating and pivoting motion can differ from continuous rotation because the contact region and heat flow change. Intermittent duty can permit cooling during pauses, but that requires a matching correction method rather than a simple average speed. Use the manufacturer’s curve or calculation tool for the actual material and operating mode.

Avoid unit and lubrication errors

Do not multiply MPa by feet per minute or psi by metres per second and compare the result directly with the source table. Convert one term so the product units match. Do not apply a dry-running value to a lubricated design without the manufacturer’s stated correction. Likewise, do not treat a static surface-pressure figure as the PV limit: one is a pressure criterion, while the other includes sliding speed. If a source uses a graph rather than one constant, preserve the graph’s pressure and speed conditions in the design decision.

Selection boundary and sources

Treat the table as a compact pointer to manufacturer data, not a bearing certification. Verify grade availability, temperature range, shaft pairing, tolerance, moisture or chemical exposure, and the full load spectrum with the current product documentation. If the application is safety-critical or downtime is costly, obtain supplier engineering review and test the assembled bearing under representative conditions. The three cited igus pages below provide the reported PV values and material-specific operating boundaries; those source conditions are part of the data, not optional footnotes. Also verify whether the actual part dimensions match the test bushing and whether the load is evenly distributed across the projected bearing area. Misalignment and edge loading can create local pressure far above a simple average.

References

• igus iglide G material data
• igus iglide P material data
• igus iglide A200 material data

This reference is limited to the conditions named in the data and sources. Confirm the governing specification, complete geometry, material, operating environment, and service loads before using any value for design, procurement, inspection, or safety-critical decisions.