Shaft Collars
The Shaft Collars is a cylindrical mechanical part that’s positioned on the rotating shaft and can be an integral area of the sliding bearing.
Generally, the Shaft Collars and the bearing housing have an interference fit and a clearance fit with the shaft.
1, concept
A sleeve made of a full cylindrical protective shaft is called a Shaft Collar.
The bearing shell is equivalent to the external 
ring of the sliding bearing, the sleeve is integral and the contrary shaft is moving, while the bearing shell is segmented and the opposite shaft is rotating.
In the LEGOMindstorms series and BioTransRoSys series of robot components, the sleeves are particularly known as the silver-gray LEGO standard shaft holders, which are divided into full sleeves and 1/2 sleeves.
The main materials of all kinds of Shaft Collarss on the main hydropower producing units are ZQAl9-4, ZQSn10-1 and ZQSn6-6-3.
2, the difference
A Shaft Collars is a sleeve on a propeller shaft or a yoke shaft. Bearings (known as “shafts” in Japan) are components that fix and decrease the coefficient of friction of the load during mechanical transmission.
The similarity between your Shaft Collars and the bearing is that both bear the load of the shaft.
The difference between your two is that the sleeve is of integral structure, and the relative motion between your shaft and the sleeve is when rotating; and the bearing is definitely split, and the rotation may be the relative motion of the internal and outer bands of the bearing itself. But in essence, the Shaft Collars is truly a kind of sliding bearing.
3, common factors behind damage
During the long-term procedure of the Shaft Collars, the surface of the journal is subjected to the pressing drive of the expansion sleeve and the composite mechanical force, that will cause its permanent deformation, and the diameter may be reduced by 0.1mm~0.3mm. As a result, the mechanical growth and the effectiveness of the force are not up to the mandatory tightening power, and a matching gap occurs between your sleeve and the main shaft, causing use of the sleeve.
4, the most recent Taper Lock Pulley repair method
Due to the large value of components, the traditional repair strategies are relatively expensive. With the development of advanced technologies such as for example polymer composite materials abroad, some repair strategies with quick restoration and low priced are favored. This technique has also been presented in China, and the more mature Fushun Blue 2211F components. The material gets the extensive mechanical properties, exceptional adhesion and heat range and corrosion resistance which can’t be compared with the traditional method. The maximum compressive power can reach 1200kg/cm2, and the adhesion (overlap shear tensile check) can be 225kg on the smooth steel surface. /cm2. Therefore, it can be used for the repair of wear of large Shaft Collars parts. Moreover, the equipment doesn’t need to be disassembled in a huge level, which saves a whole lot of manpower and material resources for the enterprise.