TECHNICAL INFORMATION

Split Roller Bearings

Delivering the highest radial and axial capacity split roller bearing currently within the market and intended for both the ‘free’ and ‘fixed’ bearing positions, Bowman Advanced Split Roller Bearing units have the ability to adapt the ‘free’ bearing into a ‘fixed’ bearing via the addition of split thrust roller (axial) bearings
within the bearing housing.

The resulting ‘fixed’ bearing is capable of handling high axial loads in either direction – with no decrease in radial performance (unlike spherical and taper roller bearings), due to the unit’s independent thrust bearings. Each bearing performs one task only – compared to competitor’s units which employ multirole rollers. ‘Free’ bearings have plain outer races to allow unrestricted axial movement of the rollers with thermal expansion and contraction.

For a comprehensive overview of the full product specification, capacities and dimensions download the full catalogue here…

Bearing Rating

Bearing ratings for dynamic radial capacity (CR), dynamic axial capacity (CA), static radial capacity (COR) and static axial capacity (COA) shown in this catalogue are based on ISO 281-1990 (dynamic capacity) and ISO 76-1987 (static capacity) respectively.

Radial and axial loads can be considered independently and Bowman Advanced Split Roller Bearing units isolate one from the other.

Calculating Bearing Radial Life

Expected radial bearing life is calculated by the following equation:

Calculating Bearing Axial Life

Expected axial bearing life is calculated by the following equation:

Static Ratings

The static rating is defined as that load which causes a permanent deformation of 0.0001 times the diameter of the roller and can be considered to correspond to a contact stress of 4,000 MPa at the centre of the most heavily loaded roller.

Bearing Minimum Radial Loading

To avoid excessive skidding of the radial rollers, sufficient radial load must be applied to the bearing. Generally, radial load with a magnitude of 1% of the dynamic radial capacity of the bearing would be required to drive the radial rollers.

Shaft Tolerance

Split roller bearings rely on accurate shaft form and diameter to ensure the desired bearing diametric clearance is obtained. Journal diameter at bearing seating is generally required to be within h7 tolerance (based on BS4500 / BS-EN-ISO 286-2) for most applications.

Where shaft speeds and loads permit, wider tolerances can be used.

Generally:

h6 tolerance should be applied where speed is over 150,000dn mm
h7 tolerance can be applied for speeds between 50,000dn mm and 150,000dn mm

For speeds under 50,000dn mm, h9 tolerance can be applied

NOTE: ‘dn’ is an expression of shaft speed used by bearing manufacturers, where:-‘dn’ = bearing bore (mm) x shaft speed (rpm).