Bearing PV Value

The maximum operating PV value of EPJ plastic bearing is 0.4 N/mm²·m/s. It means the load capacity of the bearing is inversely proportional to speed. Refer to Diagram EPJ-1 for details.

Bearing Load, Speed and Temperature

The maximum static load of EPJ plastic bearing is 35 MPa. Refer to Diagram EPJ-2 for the maximum compressive deformation of the bearing under this load. The actual working load of the bearing shall be slightly less than 35 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: 90°C) will gradually reduce the bearing load capacity. Refer to Diagram EPJ-3 for load variation with bearing operating temperature.

Friction Coefficient of Bearing

Diagram EPJ-4 shows that the friction coefficient of EPJ plastic bearings has a relatively small rate of change with movement speed under constant load. Diagram EPJ-5 indicates that at a constant movement speed, the friction coefficient changes significantly when the load is less than 10 MPa, while the rate of change gradually decreases when the load exceeds 10 MPa. Diagram EPJ-6 shows that the friction coefficient of EP plastic bearing material increases as surface roughness rises; however, the friction coefficient tends to stabilize once roughness exceeds Ra 0.5 μm. This bearing is recommended for shafts with surface roughness of Ra 0.1~0.4 μm.

Wear and Shaft Material

Diagram EPJ-7 presents the wear test results of EPJ plastic bearings operating on different shaft materials. Diagram EPJ-8 shows that EPJ plastic bearings are compatible with various shaft materials when operated under loads below 2 MPa, with the lowest friction and wear achieved on hard chrome shafts. As the load increases further, the bearing exhibits particularly outstanding wear resistance when paired with stainless steel shafts. Diagram EPJ-7 also shows that EP plastic bearings are more suitable for rotary motion. Regardless of rotary or oscillating motion, the bearing delivers the best performance when used with hard chrome shafts.

Chemical Resistance

EPJ plastic bearings resist corrosion from weak alkalis, weak acids and various lubricating oils.

Water Absorption

EPJ plastic bearings have a moisture absorption rate of 0.3% under standard atmospheric pressure, and the maximum water absorption when immersed in water is 1.3%. Due to its low water absorption, bearing design modifications are only required for extreme applications.

UV Resistance

When EPJ plastic bearings are exposed to ultraviolet radiation for a long time, there is almost no color change. The hardness, compressive strength and wear resistance of the material remain unchanged.

Installation Tolerance

Tolerance of EPJ plastic bearing after press fitting