Specialist knowledge | Design and calculation

Specific load capacity C10

Definition

The specific loading capacity C10 is the radial load capacity of a 10 mm long ball zone of a MarMotion rotary stroke bearing, taking into account the nominal diameter dw, the preload v and cage type N 500, N 501, N 511 or N 502.

The specific radial force P10 is to be determined based on the load on the rotary stroke bearing.

The following must always apply:  P10 ≤ C10

C10 is dependent on: Nominal diameter dw, ball diameter k and the number of balls, preload v and the surface pressure criteria at the points of contact between the rolling elements and the surfaces of the guide shaft and guide bush (Hertzian stress), as well as the elastic deflection of the shaft axis from the centered position, are calculated using the value R10 suspension of a 10 mm long ball zone.

The specific load ratings C10 of Mahr ball cages N 500 and N 501 in the table Specific load rating C10 and suspension R10 were determined while maintaining the claim of the MarMotion rotary stroke bearing.

The elastic deflection with a load P10 = C10 should not be higher than half the value of the preload v.<br/> δR,max = 0.5 v [µm]

Values C10 and R10 in the table are specified as a function of the preload v so that this condition is met. The suspension R10 [µm/N] is the deflection of the axis of a 10 mm long ball zone with a radial load of 1 N applied.

The deflection of a 10 mm long ball zone is calculated from: A10 = P10 · R10  [µm]

Calculation method I

After determining the specific radial force P10, the required nominal diameter dw is taken from one of the tables, for which an equally high or higher value C10 applies.

Calculation method II

Due to the given nominal diameter dw, C10 is taken from one of the tables and used as the permissible specific radial force P10 for the subsequent calculation.<br/> Note: The calculation formula for P10 can no longer be used when contact path e <60 mm (section Radial load as pure torque) as moment factor g is not accurate enough due to the empirical determination.

Ball cage type N 501:<br/> Specific load rating C10 and deflection R10<br/> The values C10 and R10 are specified for the permissible preloads.

Ball cage type N 500:<br/> Specific load rating C10 and deflection R10<br/> The values C10 and R10 are specified for the permissible preloads.

Specific load rating C10 and suspension R10

  Preload v [μm]
Parameter
dw [mm]
C10 [N]
R10 [μm/N]
567891012
18 - 20C10
R10
188
0.014
248
0.013
312
0.012
382
0.011
   
24 - 25C10
R10

300
0.01
370
0.009
460
0.009
550
0.009
  
30 - 32C10
R10


380
0.01
470
0.009
560
0.009
660
0.008
 
38 - 42C10
R10


443
0.009
540
0.008
645
0.008
750
0.007
1000
0.007

The values C10 and R10 are specified for the permissible preloads.

  Preload v [μm]
Parameter
dw [mm]
C10 [N]
R10 [μm/N]
123456789101214161820
4C10
R10
12
0.0075
25
0.055
42
0.042
            
6C10
R10

25
0.042
45
0.035
70
0.030
           
8C10
R10


50
0.033
75
0.03
101
0.027
          
10C10
R10



78
0.027
110
0.025
144
0.023
         
12C10
R10



92
0.023
130
0.021
170
0.019
         
14-16C10
R10




141
0.02
185
0.018
233
0.017
285
0.015
       
18-20C10
R10




163
0.017
215
0.015
270
0.014
331
0.013
       
24-25C10
R10





276
0.012
350
0.011
424
0.011
500
0.01
      
30-32C10
R10






380
0.01
462
0.01
560
0.009
650
0.009
     
40-42C10
R10






410
0.009
495
0.009
590
0.009
690
0.008
910
0.007
    
50-52C10
R10







552
0.008
658
0.008
770
0.007
1030
0.006
    
63C10
R10








670
0.008
780
0.007
1050
0.006
1370
0.006
   
80C10
R10









846
0.007
1110
0.006
1430
0.006
1720
0.005
  
100C10
R10










1230
0.005
1560
0.005
1880
0.005
2280
0.004
2660
0.004

The values C10 and R10 are specified for the permissible preloads.

To top