Slewing Ring

Slewing rings are necessary when in the inside of machine or in an application, a structural part has to rotate with respect to another part, on a single axis, guaranteeing the link between those parts



Slewing Bearing Definition

Slewing bearing is a large bearing with special configuration, which can endure biggest multiply load, such as axial&radial load, overturning moment,etc.


Slewing Ring Structure

Slewing ring is composed of outer ring (teeth or non-teeth),rolling (steel ball, cylindrical roller, tapered roller), cage, inner ring(teeth or non-teeth) and seals (the one with sealed structure).


Slewing Bearing Function

Slewing bearing itself is featured in compact structure, convenient lead to slew, easy for installation&maintenance, which is widely used as slewing set in the fields of heavy machine, slewing platform in the steelworks, excavator grab, material taking&stacking set, material traveler, harbor machine, missile lauching cage,CT set, etc.


Materials for Slewing Bearing

1)Rings: Steel 45#,50Mn(carbon structural steel), 42CrMo (alloy structural steel). 50Mn and 42CrMo are usually used.

2)Rolling : It is made of chrome steel GCr15 or GCr15SiMn.

3)Seal: It is usually made of NBR,iron,felt,or other thing which meet the capability.


Hardness: Normalizing hardness of the rings is 187HB-241HB, quench & temper hardness is 229HB-269HB, hardness of the raceway after quenching is 55HRC-62HRC.


Slewing Bearing Transportation 

Delivery:   Stock product in 7 days
                  Standard product in 30 days
                  Custom product in 40-60 days
Package: Three layers in wood cases.
Transportation types: By sea, By air, By currier



Normally we have structure for slewing bearings as below:


Single-row four point contact ball slewing bearings

Single-row light weight series slewing bearings



Single Row Cross Roller Slewing Ring Bearings 

Double-row ball slewing bearings 

Three-row Roller Slewing Ring Bearings

Accept custom making according to drawing or requirment.


Slewing Bearings Main Applications


For further detail information, please click the below application name you need.


Slewing Bearings for Excavator

DRE supplies the slewing rings to a wide range of the excavators, a good replacement of excavator slewing ring bearings used on Komatsu, Hitachi, Kobelco, Caterpillar,  and so on, we can supply according to the most of the machine number, and a lot of slewing rings are in stock for the quick delivery.


Slewing Bearings for Cranes

Because of the light structure of the crane, slewing ring bearing is an essential and strategic part. Our slewing rings are widely used in kinds of cranes, such as tower cranes, ship deck cranes, mobile cranes, railway cranes and so on.


Slewing Bearings for ship & offshore

Because of the special condition for the slewing rings used for the offshore, we have special strong design on the sealing system and the surface protection. Our specific design satisfy the main manufacturers of the on board and harbour cranes, winches, davits and rubber tired gantry cranes as well as propellers.

All our slewing bearings follows the international certification standards and can accept the inspection such as DNV, GL and others.


Slewing Bearings for Wind Turbines

Wind Turbines Slewing ring bearings can be classified into three types: the yaw bearing, pitch or blade bearing, driving system bearing (spindle bearings and gearbox bearing).

The yaw bearings install into the joint between tower and cabin, the pitch bearing installed into the joint between the blades and hubs. Each wind turbine has a set of yaw bearing and three sets of pitch bearing.

Structure of Yaw and Pitch Bearing

Generally, the structure of yaw and pitch bearings is single row ball slewing ring four-point contact bearing and double row ball slewing ring four-point contact bearing. and both these two types can be further divided into bearings without gears, bearings with internal gears ,bearings with outer gears according to gear position .


Fastening Bolts for Slewing Bearings 

DRE can supply the fastening bolts for the slewing ring bearings for mounting. We can produce as customer requirements. Normally the bolts can use the same material as the slewing ring bearings, or also can use others as requires. And we can produce the match pinion of slewing rings according to the spec if customers purchase pinion together with slewing bearings.


Slewing ring refurbishment  

Slewing ring refurbishment can offer significant savings when compared to a replacement slewing ring. Repair or refurbishment is usually only economic on slewing ring with large bore size and depends on the degree of wear or damage. Repair on smaller slewing rings is possible, but only becomes economic on larger batch sizes.

Certain types of damage are easy to repair, such as minor surface scuffing or light staining. Moderate surface conditions, such as corrosion, indentation of fine spalling, and more difficult tpo repair and will probably require raceway grinding. Also some bad condition we have to change the rollers/balls and cage, re-grinding on the raceway and surface. It all depends on the status of the slewing rings.


So if you want to repair on your slewing ring, please contact with us to show the condition of the slewing rings and better the photos to let us check if can be repaired and give you the repair suggestion on this.


Forged Rings for Slewing Rings

We can also provide Forged Rings for Slewing Rings . We can supply the material of C45 steel, 50Mn, 42CrMo material. Normally we deliver the forged rings after rough machining, and the tolerance can be discussed case by case. 

We determine the hardness according to the diameter of depression in the forged rings.