Bearing PV Value

The maximum operating PV value of EPW plastic bearing is 0.5 N/mm²·m/s. It means the load capacity of the bearing is inversely proportional to speed. Refer to Diagram EPW-1 for details.

Bearing Load, Speed and Temperature

The maximum static load of EPW plastic bearing is 60 MPa. Refer to Diagram EPW-2 for the maximum compressive deformation of the bearing under this load. The actual working load of the bearing shall be slightly less than 60 MPa. The load capacity is also affected by operating speed and temperature. Higher speed (Vmax: 1.0 m/s) will raise frictional temperature, and temperature rise (Tmax: 90°C) will gradually reduce the bearing load capacity. Refer to Diagram EPW-3 for load variation with bearing operating temperature.

Friction Coefficient of Bearing

Diagram EPW-4 shows that the friction coefficient of EPW plastic bearings is less affected by changes in movement speed. Diagram EPW-5 indicates that the friction coefficient of EPW plastic bearings decreases significantly with increasing load and gradually stabilizes when the load exceeds 20 MPa. Diagram EPW-6 shows that the friction coefficient of EPW plastic bearings is relatively insensitive to shaft surface roughness. Even so, it is recommended that the shaft surface be neither overly smooth nor excessively rough. The recommended shaft surface roughness is Ra 0.3~0.6 μm.

Wear and Shaft Material

Diagram EPW-7 shows that when EPW plastic bearings operate under rotary motion at 2 MPa, wear varies significantly with different shaft materials. Tests demonstrate that EPW plastic bearings are well suited for hard chrome shafts under rotary motion. EPW plastic bearings achieve good operating performance when paired with hardened steel shafts and hard chrome shafts. Diagram EPW-8 indicates that hard chrome shafts are more suitable for EPW plastic bearings under high loads. As the load continues to increase, the bearing wear rate changes slightly. Diagram EPW-8 illustrates the differences of EPW plastic bearings under various load conditions.

Chemical Resistance

EPW plastic bearings resist corrosion from weak alkalis and various lubricating oils.

Water Absorption

EPW plastic bearings have a moisture absorption rate of 1.3% under standard atmospheric pressure, and the maximum water absorption reaches 6.5% when immersed in water. Due to its high water absorption property, the application environment of this bearing must be taken into consideration.

UV Resistance

Upon long-term exposure to ultraviolet radiation, EPW plastic bearings will experience color fading, while the material properties remain basically unchanged.

Installation Tolerance

Tolerance of EPW plastic bearing after press fitting