How to machine a shaft worn by bearings?
Thread Content
During production, one of the shafts suffered wear due to bearings, resulting in its radius decreasing by approximately 2–3 mm. Now that the bearings have been replaced, it’s not possible to install the shaft again. Apart from manufacturing a new shaft, are there any other good methods for filling in the worn areas so that the bearings can be installed once more? Thank you!
Our approach is to weld and repair the bearing seat before machining it again.
Your wear level is a bit high; if it were lower, there’s a repair agent available that you could try.
I was thinking that by replacing the bearings and modifying the bearing housings, it might be simpler. Also, are there any types of repair materials that can withstand wear and the heat generated by bearings operating at high speeds (at least 80–90 degrees)?
At the factory, parts are first weld repaired and then sent to a lathe for machining and alignment
Re-adjust after patch welding. I wonder if a condom can be added? ? ?
There are many methods for repairing worn shaft journals; I’ll list them here. If there are any mistakes, please feel free to point them out and provide corrections. 1. Wear in small clearances (under 25 microns): Rolling bearings can be fixed in place using Loctite adhesive (different adhesive types are available for different clearances), and there is no problem with this. 2. Wear due to small gaps: For sliding bearings, machining can be carried out after thermal spraying or shot welding; composite materials such as Belzona and Loctite can also be used for repair, either through on-site molding or further processing. But note that the heat resistance of composite materials is limited; moreover, both the load and rotational speed have certain ranges, so it’s not possible to increase them abruptly. 3. Wear or damage due to large gaps: Damage exceeding one-tenth of the shaft diameter requires, depending on the operating conditions, a strength assessment of the shaft journal first. Not all cases can be repaired; as long as the strength still meets the requirements for use, methods such as sleeve installation, surfacing, spray welding, or repair using composite materials can be employed. However, it is still necessary to conduct a strength assessment. The owner can also replace the bearings and bearing housings, but if they wear out again, it’s not possible to keep reducing the size of the shaft.
I really want to know what material the shaft is made of and how big it is There are many ways to repair it, but the question is whether it is worth repairing at all. If the shaft is not large, not very complex, and of low value, then repairing it makes no sense. In any case, 3 mm of wear is already a very serious level of wear; identifying the cause of this wear is the key to solving the problem. The fact that such severe wear was only noticed now also calls for a reevaluation of the equipment’s management and maintenance practices.
Since the original motor was imported from Japan, the specific material is not well known. However, if it is processed manually, 45# steel might be used along with a case hardening treatment. But Pei is preparing to fit sleeves, and surfacing processing could cause deformation of the shaft (the shaft diameter is DN40).
For rolling bearings, they can be treated by laser welding followed by further processing, or by brush plating. In the case of a sliding bearing, if the strength requirements are met, grind the shaft and reinstall the bearing. But there will be a chance to reprocess the shaft to restore it in the future.
It is also no problem for the journal to return to its original size after being chromium-plated. If it is a sliding bearing, and the journal is worn down, replacing the bearing is also an option.