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Single row four point contact ball bearings are routinely used as slewing bearings to take heavy loads under a combination of eccentric axial load and radial load for applications such as excavators, cranes, etc. The calculation method of the equivalent loads for the slewing bearings was introduced in SAE 2010-01- 1892.1) However, in this previous paper the calculation method could not be applied when an axial load does not exist. The specific case with no axial load but with a moment due to an eccentric radial load is introduced in this paper. When the eccentric radial load is applied, the bearing takes ball loads on both sides of each raceway. As a result, simple equations were obtained to calculate the static and dynamic equivalent loads, as well as the safety factors and bearing lives for slewing bearings under this condition.

Single row four point contact ball bearings are routinely used as slewring bearings to take heavy loads under a combination of eccentric axial load and radial load for applications such as earth moving equipment, construction machinery, mining and handling machines, excavators and cranes, etc. The calculation method of the equivalent loads for slewring bearings was introduced in SAE 2006-01-35541 ) , but only dealt with the case in which the bearing takes a tilting moment due to combination load. In this paper, two additional load case conditions are analyzed: one is the case in which the bearing takes all ball loads only on one side of each raceway axially, and the second is the case in which the bearing takes ball loads radially on both sides of each raceway.

Slew ring bearings are routinely used to take heavy loads under a combination of eccentric axial load and radial load for off-highway vehicles applications such as excavators and cranes. The type and size of the bearing are determined based on a safety factor and rolling life calculated using a comparison with static & dynamic equivalent loads vs. dynamic load ratings. In this paper, the static and dynamic equivalent loads are calculated for three roller type slew ring bearings. As a result, a manual calculation method was obtained to determine the static and dynamic equivalent loads, as well as safety factors and rating lives for each row of the three roller type slew ring raceways under simultaneous eccentric axial load and radial load.

Slew ring bearings takes axial and radial loads and moment simultaneously and are used in rotating mechanisms such as excavators and cranes for earthmoving equipment. For these applications, a cross roller bearings can be used and feature more stiffness than the ball type bearings. In this paper the static and dynamic equivalent loads are calculated for the cross roller type slew ring bearings such as cylindrical roller and tapered roller bearings. As a result, simple formulae were obtained to calculate the safety factors and bearing lives for the cross roller slew ring bearings under simultaneous eccentric axial load and radial load.

Single row four point contact ball bearings are routinely used as slew ring bearings under a combination of axial and radial loads and moment. Features such as gear teeth and mounting holes can also be integrated into these bearings, so specific hardness levels and hardening depths are often required on the induction hardened raceways. It is also important to evaluate the static safety factor and the dynamic life. However, there is currently no published description of the theoretical load calculations for this type bearing. Therefore, the static and dynamic axial equivalent loads for these bearings are calculated.