Scraping and lapping of the oil retention points on the bearing shells.
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Finally, when scraping the bearing shells, is it necessary to scrape the oil retention points as well? Could anyone who has photos of the oil storage points send them? Thank you.
Lapping of bearing shells is hardly used these days; with the improvement in manufacturing techniques and the widespread use of pressure lubrication, there is little need to create oil retention patterns by lapping. In the past, fish-scale patterns were created through lapping, and cross-shaped marks were made on the surface of the shell to serve as oil channels.
At high speeds, there is no need to scrape the oil storage areas on the bearing shells, as the shaft rises at high speeds and forms an oil film; therefore, those oil storage areas do not need to be scraped. At low speeds under heavy loads, the shaft fails to rotate; when the oil does not reach the lowest point of the bearing shells, it is necessary to scrape off excess oil to prevent bearing damage. After scraping the contact surface during tile scraping, make small pits in the areas that are not in contact, using force, to create oil storage pockets.
Oil storage tanks were used in the past when there were no oil pumps. Nowadays, with high-pressure oil pumps available, it is necessary to turn on these pumps before the shaft starts to rotate; once the high-pressure pumps are activated, the shaft is lifted, which creates an oil film between the shaft and the bearing surfaces. The high-pressure pumps are then turned off after the equipment begins to operate, so this is no longer necessary today.
Ordinary thin-walled bearings need to be lapped, while the rest of the shaft bearings are basically manufactured in one go and do not require further lapping!
If it is a high-speed shaft with thick bearing shells, a small pit needs to be carved in the part of the upper shell that faces the direction of rotation of the shaft. As the shaft rotates, lubricant is drawn into this pit, from where it then falls freely, thereby providing lubrication. These types of tiles are now almost nowhere to be seen. For thin-walled tiles, use a scraper on the bus alloy to create intersecting parallel diagonal lines or fishbone patterns in order to facilitate the spread of lubricating oil.