Journal Bearings and Friction Circle

Journal bearings are used to support rotating shafts and their primary function is to reduce friction between the rubbing surfaces of the journal and the bearing. The frictional losses are caused by the sliding motion of the journal within the bearing. The frictional losses lead to the generation of heat which can cause wear and tear of the bearing surfaces. The friction circle is a graphical representation of the frictional forces acting on the journal and the bearing surfaces.

Effect of Load on Friction Circle

The friction circle is a circle that represents the maximum frictional force that the bearing can withstand without causing damage to the bearing surfaces. The radius of the friction circle is directly proportional to the load acting on the bearing. The load acting on the bearing causes the journal to press against the bearing surfaces, leading to an increase in the frictional forces acting on the surfaces. The increase in frictional forces leads to an increase in the radius of the friction circle.

Effect of Other Parameters on Friction Circle

Although the load acting on the bearing is the primary factor that determines the size of the friction circle, other factors such as the viscosity of the lubricant, speed of the journal, and radius of the journal can also affect the size of the friction circle. However, their effect is comparatively smaller than the effect of the load acting on the bearing.

Conclusion

In conclusion, the radius of the friction circle in journal bearings increases with an increase in the load acting on the bearing. The load acting on the bearing causes an increase in the frictional forces, which in turn increases the radius of the friction circle. Other factors such as the viscosity of the lubricant, speed of the journal, and radius of the journal can also affect the size of the friction circle, but their effect is relatively smaller than the effect of the load.