PV means pressure × velocity. For a custom bronze sleeve bushing, the operating PV value helps describe the duty before material and lubrication are reviewed.
This guide covers a radially loaded sleeve bushing with continuous shaft rotation. It explains the calculation, not a universal PV limit for bronze. JEDBUSHING makes bushings to reviewed drawings; suitability still depends on the alloy, construction, shaft, lubricant, and working conditions.
What Does PV Mean for a Bronze Sleeve Bushing?
In a bushing PV calculation, P is average radial load over the projected area, approximately shaft diameter × bearing length, rather than the full curved surface. V is sliding speed at the shaft. Their product is operating PV. Fairfield University’s plain-bearing lecture discusses projected pressure in bearing design.
This calculated P is an average nominal pressure, not the highest pressure at every point of contact. Misalignment or edge loading can create a more demanding local condition.
Pressure describes the load per projected area; velocity describes how fast the surfaces slide. A bearing PV value combines them, but two applications can have the same PV with very different pressure and speed. Check both values separately.
A published limiting PV rating differs from the operating PV calculated for your machine. It belongs to a specified material and test conditions, not to every product called a bronze bushing.
How to Calculate Pressure, Velocity and PV
For a continuously rotating shaft, start with four inputs:
- F: Radial load carried by the bushing being checked, in newtons (N).
- d: Shaft diameter at the bearing, in millimeters (mm).
- L: Axial length supporting the radial load, in millimeters. Do not include a flange that does not support the radial load; identify any relief or feature that changes the working area.
- n: Shaft rotational speed, in revolutions per minute (rpm).
Then calculate:
P = F ÷ (d × L), in N/mm², which is numerically equal to MPa.
V = π × d × n ÷ 60,000, in m/s when d is in millimeters.
PV = P × V, in MPa·m/s.
The factor 60,000 converts millimeters to meters and minutes to seconds. Keeping units consistent is essential: inserting an inch diameter into the metric formula will give a wrong result. If you need help defining ID, OD, length, and wall thickness on a custom part, see our bronze bushing dimensions guide.
Some catalogs use psi·ft/min for PV. Convert units before comparing their numerical ratings with a result in MPa·m/s.
Worked example: Assume one sleeve carries 1,200 N of radial load on a 40 mm shaft across 50 mm of bearing length while the shaft rotates at 300 rpm.
- Pressure: P = 1,200 ÷ (40 × 50) = 0.60 MPa.
- Surface speed: V = π × 40 × 300 ÷ 60,000 ≈ 0.628 m/s.
- Operating PV: 0.60 × 0.628 ≈ 0.377 MPa·m/s.
This example is neither a JEDBUSHING material rating nor proof that a particular bushing will work. The actual duty and acceptable limits still need review.
What a Calculated PV Value Can and Cannot Tell You
Compare operating pressure, sliding speed, and PV separately with material-specific data for the proposed bearing. Meeting a PV limit does not excuse exceeding an individual pressure or speed limit. An oil-impregnated bearing, solid cast bronze sleeve, and graphite-plugged part cannot share a generic “bronze PV limit.” See our cast versus oil-impregnated bronze guide for the construction differences.
PV is also not a service-life calculation or a direct measurement of bearing temperature. Lubrication supply, shaft finish and hardness, installed running clearance, alignment, duty cycle, and contamination affect wear and heat. A suitable material on paper may perform poorly if the oil path is blocked or the shaft is misaligned. Our press-fit and running-clearance guide covers one important part of the assembly check.
For oil-lubricated rotation, a PV below a published limit also does not establish an adequate oil film. Oil supply, viscosity, and operating temperature require their own assessment.
The rotation formula does not describe a short-angle pivot, straight sliding motion, or thrust washer carrying axial load. Their travel or contact area differs. For these parts, report the motion type, stroke or angle, cycles, and loads for separate review.
Send Your Bronze Bushing Operating Data for Review
JEDBUSHING manufactures custom tin bronze bushings, flanged sleeves, and other machined bronze parts from drawings and reviewed requirements. We can discuss the material, dimensions, grooves, and inspection needed for your application.
Send your drawing or inquiry with the shaft diameter, bushing length, radial load on each bearing if known, speed and motion type, lubrication method, environment, material requirement, and quantity. If you have calculated PV, include P and V separately as well as the result. Mark estimates clearly so the application can be reviewed before a production specification and quotation are agreed.
Frequently Asked Questions
Can I calculate bushing PV from the total weight of the machine?
Not directly. The calculation needs the radial load carried by the specific bushing. A machine’s weight does not show how its supports share the load. Provide the assembly drawing or load information and have the bearing load confirmed before relying on a PV result.
Does changing from grease to oil change the calculated PV?
If load, diameter, bearing length, and speed stay the same, the calculated operating PV stays the same. The lubricant can change the bearing’s real operating behavior and the rating appropriate for comparison, so the material and lubrication arrangement still need review.
What if peak load and peak rpm occur at different times?
Calculate paired load and speed at each relevant operating point. Do not present unrelated peaks as the actual duty. If you also calculate their product as a conservative scenario, label it clearly and share the duty cycle.