Permissible Axial Load
Buckling Load on the Screw Shaft
With the ball screw, it is necessary to select a screw shaft so that it will not buckle when the maximum compressive load is applied in the axial direction.
Fig. 12 shows the relationship between the screw shaft diameter and a buckling load.
The buckling load can be calculated by equation (5) below. Note that in this equation, the result is multiplied by a safety factor of 0.5.
Permissible Tensile Compressive Load on the Screw Shaft
If an axial load is applied to the ball screw, it is necessary to take into account not only the buckling load but also the permissible tensile compressive load in relation to the yielding stress on the screw shaft.
The permissible tensile compressive load is obtained from equation (6).
Selection Criteria
- Operating Conditions of the Ball Screw
- Operating Conditions of the Ball Screw
- Selecting a Screw Shaft
- Selecting lead･Selecting a shaft diameter
- Mounting Procedure for the Ball Screw Shaft
- Permissible Axial Load
- Permissible Rotational Speed
- Selecting a Nut
- Calculating the Permissible Axial Load
- Considering the Service Life
- Considering the Rigidity
- Considering the Positioning Accuracy
- Considering the Rotational Torque
- Considering the Driving Motor
