How to repair the common faults of sliding bearings?
Sliding bearing belts (or without) oil-lubricated integral sliding bearings, sleeve sliding bearings and split-type sliding bearings with oil ring lubrication. Integral sliding bearings are generally used for small motors, and split sliding bearings are used for large and medium motors.
The journal sleeve of the sliding bearing slides relative to each other in the middle of the bearing, and relies on the lubricating oil film in the bearing to form a semi-liquid, semi-dry friction. Therefore, in the absence of lubricating oil, it is easy to cause serious wear of the bearing. If it is not repaired in time, the bearing temperature will rise and the alloy will melt, damage the journal or wipe the motor and rotor.
When removing the sliding bearing, the oil in the end cap tank should be poured out first. For sleeves or plain bearings, loosen the fastening screws on the outside and lay the end face of the end caps up, and the sleeve-type sliding bearing on the inside of the end cap should be placed face down. The sleeve is placed under the end cover, and the sleeve should be placed outside the bearing to prevent the oil ring from being broken or the bearing, and then the metal rod is placed on the inner ring of the bearing, and the bearing is hammered out by hand.
When repairing a plain bearing, first deposit a layer of lead on the worn surface of the bearing and then pry it into the correct aperture. The specific approach is as follows.
Before the bearing is leaded, the surface of the inner hole of the bearing is driven or cut into a dovetail-shaped groove so that the lead on the pouring is firmly combined with the bearing body. Then, tin is placed on the inner surface of the bearing, and the lead is immediately poured when the tin is not completely solidified. Before hanging the tin, apply a layer of hydrochloric acid or sulfuric acid to the surface of the tin to be hanged, rinse with hot water, and dry. When hanging tin, first use the torch to heat the bearing to the solder melting temperature of 250 ~ 270 ° C, then apply a layer of zinc chloride solution, and then sprinkle a layer of ammonium chloride powder to hang tin. When pouring lead, a core with a diameter slightly smaller than the journal is placed in the bearing hole, and the molten lead liquid is poured into the gap between the core and the bearing hole wall. The thickness of the lead layer can be calculated by the following formula:
S=0.02d+2(mm)
Where d is the journal diameter, mm.
The maximum thickness of the lead layer shall not exceed 10 mm, and the minimum thickness shall not be less than the value in Table 1.7.
When pouring lead on bronze or cast steel bearings, there is no need to drive or chisel the dovetail groove, but to hang tin. The minimum thickness of the lead layer is taken as half of the value in Table 1.7.
After the bearing has a good hole, in order to allow the grease to flow around the journal, the oil groove should be driven or drilled in the hole wall. The shape of the oil groove is various such as twill, thread and curve. The size of the oil sump is related to the journal diameter.
In addition, when opening the oil groove, it cannot be opened at the part where the inner wall of the bearing is subjected to the axial pressure, nor can it be opened at the edge of the bearing to prevent oil leakage.
Common fault phenomena, causes and troubleshooting methods of sliding bearings in operation
