Under long-term high-load operation of the crane, the bearing seat of the cycloid reducer often wears, heats or even breaks due to poor lubrication, vibration impact or improper maintenance. Before repair, the parts need to be thoroughly cleaned, and the wear amount and concentricity of the bearing seat hole must be accurately measured to formulate a repair plan based on this.
2. Traditional mechanical repair technology
For cast steel shells, a partial replacement method can be used: after surveying and mapping, a new high-strength bearing seat is machined, the old seat is turned away and the interface is machined, the new seat is connected through threads and then the reinforcing ribs and interfaces are welded, and finally finished to the design size. If the inserting method is used, the seat hole needs to be bored by 8-10mm, a cast steel insert with an interference fit must be pressed in, and then finished. Although the traditional process has good impact resistance, the process is complex and the cycle is long, and welding is prone to thermal stress deformation and cracks.
3. Polymer material repair technology
For on-site emergency repairs, polymer composite repair methods have significant advantages. First, the worn surface is baked with oil, polished and cleaned with absolute ethanol to ensure it is dry and strong; then the carbon nanopolymer material is mixed in proportion and applied to the worn area; then, using the unworn area as a benchmark, use a knife-edge ruler to scrape and grind to restore the original size; finally, wait 8-12 hours for solidification. This method does not require extensive disassembly, and the material has the "giveback" that metal lacks, and can achieve 100% surface fit and effectively absorb vibration and impact.
4. Assembly and debugging standards
After the repair is completed, assembly accuracy needs to be strictly controlled. When installing the bearing, there should be a radial gap of 0.05-0.10mm between the outer ring and the bearing cap to prevent thermal expansion from sticking. When assembling the cycloid wheel, you must ensure that the markings on the two cycloid wheels are 180° symmetrical to each other or overlap top and bottom. In addition, the coupling needs to be aligned to ensure that the coaxiality between the reducer shaft and the driven device shaft reaches the standard.
5. Trial operation and daily maintenance
The repaired reducer needs to be cranked manually for a week to confirm that there is no jamming or lag before it can be started. During no-load test operation, the bearing temperature needs to be closely monitored, and the normal temperature rise should not exceed 45°C. In daily maintenance, the oil quantity and quality should be checked regularly to keep the oil level consistent with the oil sight glass; at the same time, check the concentricity of the coupling parts and the tightness of the fixing bolts, and replace aging sealing rings in time to prevent dust intrusion, thereby extending the service life of the reducer.
