Specialist knowledge | Design and calculation

Permissible accelerations during linear movement

High inertia forces can occur on the ball cage during fast linear movements. During movements that are similar to sinusoidal motions, the mass forces are the highest in the end positions of the linear motion.

The magnitude of the inertia forces is influenced by the following factors:

  • Cage material: brass or plastic
  • Longitudinal acceleration b
  • Cage length L2
  • Horizontal or vertical installation position

The required ball contact length E is calculated using the quotient q based on the relationship:

Acceleration b with sinusoidal motion:

The quotient q is specified in the following tables.

The calculated value for E [mm] must be compared with the recommendations in the table. The larger of the two values is used to determine the size of the bearing. The tables contain recommended values for the permissible longitudinal acceleration with ball cage being inside the guide bush at its entire length. These values are average values that can be exceeded, for example, by increasing the preload v.

Installation
dw [mm]q [s2/m]bmax [m/s2]
Ball cage made of N 500 plastic
18 - 190,5200
24 - 250,5200
30 - 321,191
40 - 421,191
Ball cage made of N 501 brass
40,7150
61100
8 - 121,567
14 - 161.7557
18 - 20250
24 - 252.540
30 - 323.330
40 - 42425
50 - 52520
636.615
801010
1001010
dw [mm]q [s2/m]bmax [m/s2]
Ball cage made of N 500 plastic
18 - 191.3575
24 - 251,471
30 - 323.132
40 - 423.231
Ball cage made of N 501 brass
40,9110
61,470
8 - 12250
14 - 162.343
18 - 202.638
24 - 253.330
30 - 324.423
40 - 425.319
50 - 526.715
638.611
80137.6
100147
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