Common questions

How does a slewing bearing work?


How does a slewing bearing work?

Slewing bearings comprise an inner ring and an outer ring, one of which usually incorporates a gear. Together with attachment holes in both rings, they enable an optimized power transmission with a simple and quick connection between adjacent machine components.

How do you measure a slewing bearing?

Place the slewing bearing on the platform vertically, lift a slewing ring, Measure the clearance with the dead weight of the other slewing ring, Measure three point along the circumference of 120° and take the average . Other measurements are allowed.

What is a slewing assembly?

The slewing drive is a gearbox that can safely hold radial and axial loads, as well as transmit a torque for rotating. Slewing drives are made by manufacturing gearing, bearings, seals, housing, motor and other auxiliary components and assembling them into a finished gearbox.

What is a Rotex bearing?

Rotek slewing bearings are machine elements which absorb all axial and radial forces and the resulting tilting moments in a single self-retaining and ready-to-install unit.

What is rocking test of Crane?

The rocking test comprises the measurement of the deflection between the crane pedestal and the rotating crane housing in the way of the slewing ring using a dial test indicator to determine the bearing clearances.

What is a slew motor?

Slew motors, also referred to as swing motors or swing drive motors, provide rotation. For example, a slew motor is what enables the house of a mini excavator to rotate 360°. On excavators (wheeled, tracked, and compact), they are usually axial piston hydraulic motors.

What is slewing in an excavator?

Slewing refers to rotating the excavator’s house assembly. Unlike a conventional backhoe, the operator can slew the entire house and workgroup upon the undercarriage for spoil placement.

Why do you use slewing ring bearings instead of two?

A slewing ring bearing has rolling elements designed to create a reactive moment within the bearing’s dimensions envelope, to oppose applied (overturning) moment load. This makes it practical to use one bearing instead of two, reducing the height required for an application and often improving performance.

What kind of gears are used for slewing bearings?

All of our slewing bearings can be manufactured with internal gears, external gears or without gearing. Special gearing, such as helical and worm gears, are also available upon request.

What kind of slewing bearings do SKF use?

SKF has extensive experience in designing and manufacturing customized or special slewing bearings, for example, slewing bearing with combined roller/ball bearing (as shown), with segmented bearing or with inserted raceways bearing. Depending on their design, slewing bearings have the following features:

How to calculate friction moment of slewing ring?

The Friction Moment can be estimated for a slewing ring bearing using the formula noted below. The resulting values assume that the bearing is mounted according to the guidelines outlined in this catalog. This estimate only applies when load is applied to the bearing, and does not reflect starting torque in an unloaded condition.