Bearing Assembly Process

In order for the bearing to function properly, it is essential to use the correct mounting method. The selection of bearings for a specific application and the method of mounting and dismounting are initially determined during the design phase. The installation process should be carried out in a clean and dust-free space as much as possible, not on a dusty production machine. Dust and debris can affect the internal clearance of the bearing and the precise fit to the shaft or bearing. Tiny dust can affect the outer diameter of the outer ring and even create gaps in the tight fit. This will cause the outer ring of the bearing to rotate in an out-of-round space. The dust on the shaft will cause the wear of the contact part between the shaft and the sealing element, resulting in the leakage of lubricating oil. The dust mixes with the lubricating oil, creating an abrasive mixture that causes bearing wear. When the new bearing is not installed, do not remove its original packaging. The new bearings are thoroughly coated with a compound anti-rust coating that seals out air, moisture and the anti-rust coating. The coating used by most bearing manufacturers is not easily removed because it is compatible with almost all petroleum-based lubricants. When using synthetic oils and synthetic greases, the protective layer compound must be removed. However, with the use of synthetic hydrocarbons, it is not necessary for the composite coating to be removed. Bearings are wrapped in heavy duty, waterproof composite laminate paper. Care should be taken not to drop the bearing or to grip the bearing tightly. Bearings should not be exposed to variable temperatures that could cause condensation. not necessary. Fingerprints can be a starting point for rust. There are three basic methods for bearing assembly: cold assembly method, hot assembly method, and hydraulic assembly method. (1) Legal cold assembly Bearing outer diameter up to 100mm can be cold assembled with sleeve and hammer or heavy pressure. Usually a normal hammer is used. Hammers with soft metal tips should not be used, as metal shavings may break off and enter the bearings. The surface of the sleeve end should be flat and parallel without burrs. Abutting it should be with the press fit collar. During assembly or disassembly, it is important to protect the shaft from being damaged by the copper pieces of the jaws/clamped in a vise. The replaced bearing must be absolutely identical to the failed bearing. Bearings and shafts are designed to fit each other and no changes can be made unless a redesigned machine is built. If the bearing and shaft fit is too loose, slippage can occur. This will overheat the shaft and cause wear on the bearing inner race and journal surfaces. If the press fit/fit is too tight, the inner ring of the bearing will be stretched so that the rollers or balls can spin freely without clearance. A manual arbor press can be used to install small bearings. Place the sleeve over the bearing with the erg. The end face should be a flat, burr-free smooth sleeve. It should be designed for an interference fit, otherwise the rollers and raceways can be damaged leading to premature failure. To facilitate installation and reduce the risk of damage, the bearing support on the shaft to be assembled should be lightly coated with a thin film of oil. It is sometimes necessary to press-fit the inner ring because the inner ring rotates and if there is some unbalanced load on the outer ring, it may cause the outer ring to creep. Effective pressing force must pass through the inner and outer rings at the same time, otherwise the bearing will be damaged. If the spherical roller bearing inner ring rotation is used in the case of an unbalanced load, a needle can be passed through the oil hole of the outer ring of the bearing to prevent the outer ring from creeping. With this arrangement a suitable outer ring is not necessary. (two), hot assembly law Hot assembly law is a method that makes assembly easier by allowing the two parts to be matched to obtain different temperatures for interference fit. The required temperature difference can be approached by 1) processing one part (this is, in general, the most common method) 2) cooling one part 3) simultaneously heating one part and cooling the other part The temperature difference method is suitable for any bearing size , both straight and tapered. Due to the equipment required, the cold loading method is used as far as possible for bearings with an outer diameter of less than 100mm. The most commonly used bearing assembly method is to install with an inner ring and shaft interference fit, and the outer ring is installed with a thin line to loosen the fit. For permanent bearings with an outer diameter of more than 100mm, the entire bearing or the inner ring of the bearing must be heated according to the heating method, so that the inner ring can be easily inserted into the shaft. In the case of separable bearings, only the inner ring needs to be heated. Bearings should be evenly carious with a maximum temperature of 121°C. Bearing heating methods are: hot oil bath, hot plate, induction heater, oven. Sealed bearings cannot be hot oiled