The Installation of Slew Rings(2)


-Securing the Slew Ring with bolts

The Slewing Ring shall be mounted in the unloaded condition.

First the toothless bearing ring is attached and then the gear bearing ring.

For good load distribution and smooth, low torque operation, the bearing should be as round as possible when the bolts are tightened. The following procedure is provided as an aid in achieving that objective.

The following procedure shall be followed in order to avoid deviations between the bolt tightening forces:

1.Lightly lubricate bolt threads in order to ensure uniform frictional resistance (does not apply to bolt locking devices with adhesive).

2.Preload the bolts, including washers, if required, crosswise in 3 steps with 30%,80%, 100% of the tightening torque or the hydraulically applied pretension force.

3.Thereby rotate the unbolted ring several times. Repeat the procedure for the bearing ring which has not yet been bolted.

When applying a hydraulic fastening device, the tightening forces for preloading shall not exceed 90% of yield stress.

4.Using a gauge, verify the bearing fully supports the mating structure. If not, then determine cause and correct.

5.Complete installation of all rotating components of significant weight, and check bearing for freedom of rotation. Excessive torque level, variation, or vibration is indicative of some unsatisfactory installation condition or component.

6.As permitted, inspect seals again for any damage.

-Determining the existing tilting clearance

When the equipment has been completely assembled, and prior to testing, check bolt tension to ensure that it is in compliance with that specified by the designer. The equipment should be oriented to generate as little moment or radial load on the bearing as possible to avoid inaccuracy in readings. Document this orientation so it may be used for all future bolt inspections. Any loss of pretensioning must be determined and eliminated.

The tilting clearance increases with raceway wear. To determine the increase in tilting clearance,it is necessary to take basic measurements after installation prior to putting the Slewing Ring into operation for the first time.Permanently designate the measuring point in the main load direction.

-Setting the backlash

In the case of geared Slewing Rings the backlash shall be set during the mounting procedure. The narrowest point of the gearing is marked in green for this purpose.

A gauge shall be used to measure the backlash. If deviations from the specified values are established the axis spacing shall be corrected by moving the pinion. Afterwards the Slewing Ring shall be rotated by one complete turn making sure that no narrow points occur.

-Operating test

If the mounting bolts are properly tightened, then the Slewing Ring shall rotate uniformly. Deviations of the mounting structure and the effect of external loads can strongly impact the friction torque.

1.Rotate the mounted Slewing Ring several times.

2.Check whether the Slewing Ring runs smoothly without jumping.

3.Perform further test runs under full load.

After the operating test, recheck the tightening torques of the mounting bolts.


Socare Slewing Bearing

More information,please click:

SOCARE® International Ltd.

No.9,Xiangtan Rd,Chengyang Dis.,

TsingTao 266043


Tel: +86.185.6391.7008

Email: janice@SOCARE®




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