Selection Calculation
Ⅰ. Supporting Load of Slewing Ring
During the use of slewing ring, it is usually endure axial force, radial force and overturning moment together. For different application situation, due to the vary of working manner and structure form, the fuction combined condition also different of the above three loads. Sometimes may be the combination of two loads, sometimes may be only one load. Generally speaking, installation of slewing ring have two kinds of mode: compressive installation and suspended installation. The load of the bearing of this two kinds of installation see as follows:
If the slewing ring is compressive installation, the customer could select and calculate as follows; if the slewing ring is suspended installation, please contact our Engineering Department for assistance.
1. Selection of Structure
Common structure of slewing ring have four kinds: single row ball slewing ring, crossroller slewing ring, doublerow different diameter ball slewing ring, threerow roller slewing ring.
Based our experience and calculation, we have follow conclution:
·Do ≤2000, single row ball slewing ring first; Do＞2000,threerow roller slewing ring first.
·For the slewing ring have the same figure size, the load capacity of single row ball slewing ring is more than the cross roller and doublerow different diameter slewing ring.
·Single row ball slewing ring of Qseries have higher compact structure, less weight and more economically. They are the first chose of single row ball slewing ring.
2. Select Product Type by Calculation
（1）Calculation of singlerow ball slewing ring
① Calculation of rated static capacity
Co = 0.6×Do×do0.5
Co ─── kN Rated static capacity
Do ─── mm Diameter of track center
Do ─── mm Diameter of ball
② Equivalent load calculation according outside compound load
Cp = Fa + 4370M/Do + 3.44Fr
Cp─── kN Equivalent axial load
M ─── kN·m Overturning moment
Fa ─── kN Axial force
Fr ─── kN Radial force
③ Safety factor
fs = Co / Cp≥fo
fo See the following table
（2）Calculation of 3row roller slewing ring
① Calculation of rated static capacity
Co= 0.534×Do×do0.75
Co─── kN Rated static capacity
Do─── mm Diameter of track center
Do ─── mm Upper row roller diameter
② Equivalent load calculation according outside compound load
Cp = Fa + 4500M/Do
Cp─── kN Equivalent axial load
M ─── kN•m Overturning moment
Fa ─── kN Axial force
③ Safety factor
fs = Co / Cp≥fo
fo See the following table
3. Select Product Type Use Static Load Curve
① Static load curve show the maximum load of slewing ring when in the static state. Each type of the slewing ring in this specimen has a corresponding load capacity curve. Load capacity curve can help customer to make an elementary chose of slewing ring. Draw the static load curve. Customer draw the static load curve based on the type which wanted to be selected. See as follows:
P1=Co
M1=Co*Do/4370（ M1=Co*Do/4500）
②The point which total axial force Fa and total overturning moment M multiply the safety factor respectively should located below the static load curve.
③ Example:Draw the static load curve of QUA1000.32 P1=Co=0.108*1000*32=3456kN
M1=Co * Do/4370=3456*1000/4370=790 kN•m
Static load curve see as following:
4、Technical Parameter of Slewing
Ring Selection After making an elementary chose of slewing ring, customer could confirm the selecting result together with our Engineering Department or provide some informations about slewing ring to our company. When the selection is made by our company, please filling ‘Technical References Concerned for Selection of Slewing Ring of Maanshan Tongli Slewing Ring CO.,LTD’ in detail, so as to provide you economical and suitable selection of the slewing ring as soon as we can.
Maanshan Tongli Slewing Ring CO.,LTD Technical References Concerned for Selection of Slewing Ring 

Name of company： Address： Contactor： Department： Telephone： Fax： 

Using condition (Model of Main Machine) 
Installing type (Compression or suspension) 

Requirement of gear shape: (inner teeth,outer teeth,no teeth or no restrict) 
Application character
Only positioning
Intermittent rotation
Continuous rotation 
Revolution per minute
Normal
Maximum 

Value of Load 

Type of Load 
Maximum Working Load 
Maximum Testing Load 
Destroy Load 

Axial Load（kN） 




Radial Load（kN） 




Overturning Moment(kNm) 




Load driving torque:Normal Maximum No. of Drive Pinion: 

Special requirement:special situation,temperature,fit size,figure size limit etc. 

Deatailed load condition 
Axial load（kN）

Radial load (kN)

Overturning moment (kNm)

Revolution per minute (rpm)

Working time (%)


1) 






2) 






3) 






4) 






。。。 











100% 

Continue working condition Life:Under the mean speed of rpm,work at least hours 

Intermittent working condition Required life:Under angular of +/ degree,work at least hours 

Please fill this table thoroughly so as to provide you economical and suitable selection of the slewing ring as soon as we can. Signature： Date： 
Appendix:Confirmation of the Load Outside the Slewing Ring When selecting the slewing ring, customer first to confirm the outside load of the slewing ring. The outside load of single row ball slewing ring is the total load after combination which include:
a.overturning moment M, N•mm
b.total axial force Fa, N
c.total radial force Fr of the fuctional surface of total overturning moment M When the outside mechanical force composing the outside load, customer should put working condition factor K into consideration which based on the working type of the machine. The following are examples of crane and excavator which explain the confirmation of outside load.(The listed calculational position not always represent the abominable condition of working condition, customer should calculate according to the maximum working condition.
1. Crane(see figure 1)
Figure 1 Crane Calculation