Sliding Bearing State Affects the Working Efficiency of Melt Pump
The high efficiency working state of the sliding bearing of the melt pump should be that the driving shaft and the inner surface of the sliding bearing can form a relatively uniform liquid film, which can completely separate the shaft from the two metal surfaces of the sliding bearing, and the liquid film will play the role of supporting the load of the shaft. When the melt pump stops running, the journal will be at the lower part of the sliding bearing. The two metal surfaces will contact directly. There is no melt lubrication in the gap between the shaft and the bearing. At the beginning of starting, the bearing will be in dry friction.
With the increase of the melt conveyed and the increase of the outlet pressure, under the action of the pressure difference between the outlet and the inlet, some melt enters the bearing clearance from the guide groove. With the uniform rotation of the shaft, a kind of melt film will form on the surface of the shaft and the bearing. At this time, the friction between the two metal surfaces will gradually decrease. When the melt film fully supports the vertical load of the rotating shaft, the friction resistance of the bearing is only the viscous resistance of the melt. At this time, the friction coefficient of the two metal surfaces will reach the ideal state close to the state of liquid lubrication. Therefore, it is impossible to achieve ideal lubrication under limited load.