Slewing reducer bearing repair method

Taiwan LTM1180 cars after long-term use of cranes, slewing pinion bearing parts of fever, abnormal noise, oil spills and other conditions within its rotary gear. Inspection found that rotary gear bearing wear fracture, bearing outer ring off.
The rotary gear housing of cast steel, weldability is poor, easy to produce white tissue, pores and cracks during welding. Two bearing holes 3524 and 3526, respectively, bearing assembly, two seats high precision holes with a diameter of (215 + 0.01) mm, (260 + 0.01) mm.
When the crane rotation, the housing bore bear certain shock and vibration, so they requested seat hole material hardness, and have a certain shock, anti-vibration performance. Here are three kinds of bearing repair methods.
1. Welding knot
Welding knot repair process is as follows: First, the rotary gear housing cleaned with a boring boring seat hole, then seat hole diameter appropriately increased; secondly, the housing in the oven preheated to about 400 ℃, then heated to red hot seat hole state (about 900 ~ 950 ℃); again, copper alloy welding electrode to a predetermined thickness, and then placed in the oven (temperature at 250 ℃ or so) slowly cooled, or heat-treated by an infrared heater ; Finally, the surfacing finishing a good seat hole to the design dimensions.
With this program advantages are: after repair Shock and vibration resistant housing bore is better, the quality more stable, longer life cycle. The disadvantage is that welding repair process is complex, long cycle, high cost, easy to wear and peel after the repair.
2. casement law
Casement Repairing process is as follows: First, the bearing hole cleaned, and then boring boring seat hole to the base hole to increase 8 ~ 10mm; secondly, machined cast steel casement, casement diameter and boring seat hole cut after the interference fit; and finally, the casement after increasing installed base hole and finishing to the design dimensions.
The program uses the advantage of simple, low cost, recovery time is short. Its disadvantage is that casement gap and the shaft demanding. If the insert sleeve holes and bearing clearance is too small, easy to make bearing fever; if Parquet housing bore and the bearing clearance is too large, easy to make the bearing slide.
3. The partial replacement method

Repairing partial replacement process is as follows: First, the rotary gear bearing parts of the mapping, and high strength material processing with a new bearing; secondly, by turning the bearing housing from the rotary gear on the car cut off, and car system that interfaces with the new production and threaded bearing connections; again, the new production of bearing shells connected together by a screw and reducer, filled with welding ribs on the gear unit housing, then welded Interface site; Finally, the new housing bore finishing to the design dimensions.
Comprehensive analysis showed that two kinds of repair method, although the former has many advantages, but it does not apply to rotary gear bearing housing repair, therefore decided to replace the method using a local repair rotary gear housing. Processing reducer bearing materials selection of high manganese steel, high manganese steel commonly have Mn13,40Mn18Cr3 and 50Mn18Cr4 like. The original hardness of the material, though not very high, but its ductility and toughness, processing hardness up HBW500.
With partial replacement method the rotary gear bearing repair, loading machine re-examination, the rotary gear is working properly.