Bearing PV Value

The maximum operating PV value of EPZ plastic bearing is 1.0 N/mm²·m/s. It means the load capacity of the bearing is inversely proportional to speed. Refer to Diagram EPZ-1 for details.

Bearing Load, Speed and Temperature

The maximum static load of EPZ plastic bearing is 100 MPa. Refer to Diagram EPZ-2 for the maximum compressive deformation of the bearing under this load. The actual working load of the bearing shall be slightly less than 100 MPa. The load capacity is also affected by operating speed and temperature. Higher speed (Vmax: 1.5 m/s) will raise frictional temperature, and temperature rise (Tmax: 250°C) will gradually reduce the bearing load capacity. Refer to Diagram EPZ-3 for load variation with bearing operating temperature.

Friction Coefficient of Bearing

Diagram EPZ-4 shows that under a constant load, the friction coefficient of EPZ plastic bearings first rises with the increase of rotational speed. After the speed reaches 0.2 m/s, the friction coefficient decreases as the speed continues to increase. Diagram EPZ-5 shows that the friction coefficient of EPZ bearings decreases gradually with rising load at a constant rotational speed. Diagram EPZ-6 indicates that the optimum mating shaft surface roughness for EPZ plastic bearings is Ra 0.4~0.7 μm.

Wear and Shaft Material

Diagram EPZ-7 and Diagram EPZ-8 show that the wear rate of EPZ plastic bearings under light loads is similar to that of other bearings, while this bearing delivers better wear resistance than other bearings under medium and high loads. Meanwhile, it can be seen that hardened shafts are suitable for EPZ plastic bearings. Diagram EPZ-7 indicates that the wear rate of EPZ plastic bearings under oscillating motion is lower than that under rotary motion, and this phenomenon is especially obvious when the load exceeds 20 MPa. For rotary motion, hardened steel shafts are recommended. For oscillating motion, stainless steel shafts or hard chrome shafts are preferred.

Chemical Resistance

EPZ plastic bearings can resist corrosion from weak acids, weak alkalis and various lubricants.

Water Absorption

EPZ plastic bearings have a moisture absorption rate of 0.3% under standard atmospheric pressure, and the maximum water absorption reaches 1.1% when immersed in water. Due to its relatively low water absorption, modification of the bearing design is only required for extreme applications.

UV Resistance

Upon long-term exposure to ultraviolet radiation, the material properties of EPZ plastic bearings will gradually degrade.

Installation Tolerance

Tolerance of EPZ plastic bearing after press fitting