Bearing PV Value

The maximum operating PV value of EPG plastic bearing is 0.45 N/mm²·m/s. It means the load capacity of the bearing is inversely proportional to speed. Refer to Diagram EPG-1 for details.

Bearing Load, Speed and Temperature

The maximum static load of EPG plastic bearing is 80 MPa. Refer to Diagram EPG-2 for the maximum compressive deformation of the bearing under this load. The actual working load of the bearing shall be slightly less than 80 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: 130°C) will gradually reduce the bearing load capacity. Refer to Diagram EPG-3 for load variation with bearing operating temperature.

Friction Coefficient of Bearing

The friction coefficient of EPG plain bearing is closely related to bearing load, operating speed and surface roughness of the shaft material. For EPG plastic bearing, the friction coefficient decreases with rising load (Diagram EPG-5) and increases with rising operating speed (Diagram EPG-4). This indicates that EPG plastic bearings are suitable for high-load and low-speed applications. Either excessively smooth or excessively rough shaft surface will increase the friction coefficient. The recommended shaft surface roughness for EPG plastic bearings is Ra 0.5~0.8 μm (Diagram EPG-6).

Wear and Shaft Material

Tests of bearings running on different shafts show that EPG plastic bearings deliver the best performance on carbon steel shafts and hard chrome-plated shafts under low loads (see Diagram EPG-7 and Diagram EPG-8). As the bearing load increases, higher shaft hardness is required. Softer shafts tend to wear first, which in turn accelerates bearing wear. When the bearing load exceeds 2 MPa, bearing wear decreases as shaft hardness increases. Diagram EPG-7 shows that EPG bearings perform better under oscillating motion than rotary motion. Under identical working conditions, wear under oscillating motion is lower than that under rotary motion, and this trend becomes more obvious especially at high loads.

Chemical Resistance

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

Water Absorption

EPG plastic bearings have a moisture absorption rate of 0.7% under standard atmospheric pressure, and a maximum water absorption of 4% when immersed in water. Due to its relatively high water absorption characteristic, the application environment of this bearing must be taken into consideration.

UV Resistance

When EPG 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 EPG plastic bearing after press fitting