Correct installation method and wrong installation demonstration of bearings

Bearing should be installed in a dry, dust-free area as far as possible, and away from equipment that generates metal chips and dust. When it must be installed in a complex environment, contamination should be minimized.

When installing the bearing, it should be carried out by mechanical, thermal or hydraulic method according to the type and size.

When installing a small bearing that is not too tight, it can be gently hammered through a sleeve and hammered. Tap the sleeve to fit the bearing into place. When knocking, it should act on the bearing ring as evenly as possible to prevent the bearing from tilting or skewing.

Most bearings are press fit. If the inner and outer rings of the bearing are to be installed on the shaft and the bearing housing at the same time, it must be ensured that the same pressure acts on the inner and outer rings at the same time, and the contact surface with the installation tool s must be on the same plane.

Normally, for larger bearings it is not possible to mount a larger bearing without heating the bearing or housing as the mounting force increases as the size increases. Big. The temperature difference between the bearing ring and the shaft or housing required for hot mounting depends mainly on the interference and the diameter of the n-bearing fit. The heating temperature of the open bearing shall not exceed 120℃. It is not recommended to heat bearings with seals and dust caps above 80°C (make sure that the temperature does not exceed the temperature allowed by the seals and grease).

When heating the bearing, it should be heated evenly, and there must be no local overheating.

The inner ring of the bearing with tapered bore is mostly installed by interference fit. The amount of interference is determined by the axial advance distance of the inner ring on the conical shaft diameter, adapter sleeve or withdrawal sleeve. The larger the thrust distance on the conical mating surface, the smaller the radial internal clearance of the bearing. The interference can be determined by measuring the clearance reduction or the axial thrust distanceo

Small and medium Bearings can be driven into position on the conical shaft diameter using a bearing installation tool or preferably a locknut. In the case of an adapter sleeve, use a socket nut that can be tightened with a hook or impact wrench. For the withdrawal sleeve, the bearing installation tool or end plate can be used to push it into the bearing bore.

Larger bearings require a lot of force to install, so hydraulic nuts should be used. The hydraulic nut can install the tapered bore bearing on the tapered shaft diameter, on the adapter sleeve and on the withdrawal sleeve.

The working principle of oil injection method is: hydraulic oil passes through oil holes and oil grooves under high pressure, and is injected into the mating surface o between the bearing and the shaft diameter. A film of oil. The oil film separates the mating surfaces so that friction between the mating surfaces is greatly reduced. This method is usually used when the bearing is mounted directly on a conical shaft diameter. The necessary oil holes and grooves should be part of the overall shaft design. This method can also be used to mount the bearing on the adapter or withdrawal sleeve if the adapter and withdrawal sleeves have been machined with oil holes and oil grooves.

The shaft and the inner hole of the bearing are too loose (commonly known as 'running the inner ring')

Due to the loose fit of the shaft and the inner hole, there is sliding between the shaft and the surface of the inner hole. Sliding friction will cause heat, and the shaft i will be damaged due to heat.

The traces of sliding between the shaft and the surface of the inner hole

The friction between the end face of the inner ring and the shaft shoulder generates heat i cracks

When 'walking the inner ringThe end face of the inner ring produces thermal cracks, and the continuous extension of the cracks will cause the inner ring of the bearing to break during use.

Adhesion occurs after heating between the shaft and the surface of the inner hole

The high temperature caused by sliding friction between the inner hole and the surface of the shaft due to the 'going inner ring' Melt surface metal and create adhesion.

The fit between the housing bore and the bearing outer diameter is too loose (commonly known as 'running the outer ring')

Because the fit between the housing bore and the bearing outer diameter is too loose, slip between their surfaces. Sliding friction will cause heat, causing the bearing to heat up and be damaged.

Sliding traces between the housing bore and the bearing outer diameter surface

Installation For bearings with an interference fit of the inner ring (or outer ring), it is forbidden to directly hit the end face of the inner ring (or outer ring) of the bearing with a hammer, so that the rib is easily damaged. The sleeve should be placed on the end face of the inner ring (or outer ring) and installed by hitting the sleeve with a hammer.

When installing a bearing with an interference fit on the inner ring, it cannot pass through the outer ring And the rolling elements transmit the force to the inner ring. This knocks out the bearing raceways and rolling element surfaces, making the bearing noisy and prematurely damaged during operation. The correct method is to use the sleeve to directly apply the force to the end face of the inner ring.

Some users use an acetylene spray gun to heat the inner bore of the bearing, when the heating temperature exceeds 727℃ (bearing steel the phase transition temperature), the metallographic structure inside the bearing steel will change. When the bearing cools, the bearing bore cannot return to its original size, usually larger than it was before heating.

The surface of the bearing heated by acetylene spray gun turns black The bearing is under force and the other row of rollers is not under force, which damages the raceway and one row of rollers on one side of the inner ring and outer ring of the bearing.