Bearing PV Value

The maximum operating PV value of EPM plastic bearing is 0.15 N/mm²·m/s. It means the load capacity of the bearing is inversely proportional to speed. Refer to Diagram EPM-1 for details.

Bearing Load, Speed and Temperature

The maximum static load of EPM plastic bearing is 30 MPa. Refer to Diagram EPM-2 for the maximum compressive deformation of the bearing under this load. The actual working load of the bearing shall be slightly less than 30 MPa. The load capacity is also affected by operating speed and temperature. Higher speed (Vmax: 0.8 m/s) will raise frictional temperature, and temperature rise (Tmax: 80°C) will gradually reduce the bearing load capacity. Refer to Diagram EPM-3 for load variation with bearing operating temperature.

Friction Coefficient of Bearing

Diagram EPM-4 shows that the friction coefficient of EPM bearings rises rapidly with increasing speed under constant load, indicating that these bearings are suitable for low-speed applications. Diagram EPM-5 shows that for EPM plastic bearings under constant speed, the friction coefficient gradually decreases as load increases. The friction coefficient and wear loss of plain bearings are greatly affected by the surface roughness of the mating shaft. Diagram EPM-6 shows that EPM bearings achieve optimal performance when operating on shafts with surface roughness Ra=0.6 μm.

Wear and Shaft Material

Diagram EPM-7 illustrates the performance of EPM bearings running on different shaft materials. It shows that when the load exceeds 2 MPa under rotary motion, the bearing performance has relatively little correlation with shaft material. It can also be seen from this diagram that EPM bearings deliver better performance under low loads. Bearing wear rises rapidly as the applied load increases. Diagram EPM-8 indicates that for high-load conditions, EPM bearings are preferably operated on hard chrome-plated shafts. Diagram EPM-7 also shows that EPM bearings exhibit significantly superior performance in rotary motion compared with oscillating motion.

Chemical Resistance

EPM plastic bearings are resistant to weak alkalis and various lubricating oils.

Water Absorption

EPM plastic bearings have a water absorption rate of 1.4% under standard atmospheric pressure, and a maximum water absorption of 7.6% when immersed in water. Due to this water absorption characteristic, the application environment of this bearing must be taken into consideration.

UV Resistance

When EPM plastic bearings are exposed to ultraviolet radiation for a long time, there is almost no change in color, and material properties remain essentially unchanged.

Installation Tolerance

Tolerance of EPM plastic bearing after press fitting