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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, cross-roller slewing ring, double-row different diameter ball slewing ring, three-row roller slewing ring.

Based our experience and calculation, we have follow conclution:

  ·Do 2000, single row ball slewing ring first; Do2000,three-row 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 double-row different diameter slewing ring.

  ·Single row ball slewing ring of Q-series 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

  (1Calculation of single-row ball slewing ring

   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

   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

   Safety factor

  fs = Co / Cpfo

  fo  See the following table

 

  (2Calculation of 3-row roller slewing ring

   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

    Equivalent load calculation according outside compound load

  Cp = Fa + 4500M/Do

  Cp───  kN           Equivalent axial load

  M  ───  kNm      Overturning moment 

  Fa ───  kN          Axial force

   Safety factor

  fs = Co / Cpfo

  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 LoadkN

 

 

 

Radial LoadkN

 

 

 

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 loadkN

 

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

  

  Q — Maximum rated lifting weight under this working condition, kg;          
  G1—Weight of hoist tool          
  G2— Weight of amplitude part          
  G3— Weight of turntable          
  G4— Balance weight            
  W1— Horizontal force of inertia, N;                                        
  W2— Wind force, N;                                                  
  W3 — Meshing force of gear, N;                                          
  L1— Working amplitude, mm;                            
  L2— Horizontal distance from gravity of amplitude part G2 to slewing center, mm;            
  L3— Horizontal distance from gravity of turntable G3 to slewing center, mm;                      
  L4 — Horizontal distance from gravity center of balance weight to slewing center, mm;            
  L5 — Vertical distance from point of horizontal force of inertia W1 to slewing ring, mm;            
  L6— Vertical distance from point of wind force W2 to slewing ring, mm;            
  g  — Gravity accleration, g≈9.8m/s2;                      
  β  — Angle between horizontal force of inertia W1 and M surface, ( ° )            
  γ — Angle between meshing force of gear W3 and M surface,  ( ° )            
  K — Working condition factor, decide by table 1.                
 
  2. Excavator(see figure 2)      
 
Figure 2 Excavator Calculation
  
  Q-Material mass in full bucket condition, kg;                           
  G1 -Bucket weight, kg;                                           
  G2-Weight of amplitude part, kg;                                    
  G3 —Weight of non-amplitude part of turntable, kg;                     
  W1—Horizontal force of inertia in revolution condition, N;                         
  W2—Wind force, N;                                                  
  W3—Meshing force of gear, N;                                         
  W4— Vertical excavate force, N;                                         
  W5—Horizontal excavate force, N;                                         
  L1  — Horizontal distance from gravity of bucket and material to slewing center, mm;         
  L2  — Horizontal distance from gravity of amplitude part G2 to slewing center, mm;         
  L3  — Horizontal distance from gravity of non-amplitude part of turntable G3 slewing center, mm         
  L4  — Vertical distance from horizontal force of inertia in revolution W1 to slewing ring, mm;         
  L5  — Vertical distance from horizontal excavate force W5 to slewing ring, mm;         
  L6  — Horizontal distance from vertical excavate force W4 to slewing center, mm;         
  L7  — Vertical distance from point of wind force W2 to slewing ring, mm;           
  β — Angle between horizontal force of inertia W2 and M surface, ( ° )           
  γ — Angle between meshing force of gear W3 and M surface, ( ° )          
  K — Working condition factor, decide by table 1.