Axial Force; Calculating The Permissible Axial Force - Siemens SINAMICS S 1PH7 Configuration Manual

3.4.3

Axial force

The axial force acting on the bearings comprises an external axial force (e.g. gearbox with
helical gearing, machining forces through the tool), a bearing pre-load force and possibly the
force due to the weight of the rotor when the motor is vertically mounted. This results in a
maximum axial force that is a function of the direction.
When using, for example, helical toothed wheels as drive element, in addition to the radial
force, there is also an axial force on the motor bearings. For axial forces in the direction of
the motor, the spring-loading of the bearings can be overcome, which under circumstances,
can result in an axial shift of the rotor. This must be prevented as otherwise it could reduce
the bearing and encoder lifetime.
Calculating the permissible axial force F
The permissible axial force F
Table 3- 12

Calculating the permissible axial force

Horizontal arrangement
F Permissible axial force in operation
AZ
F Permissible axial force as a function of the average speed
A
F Pre-loading force
C
F Force due to weight of rotor
L
1PH7 induction motors (Machine tools)
Configuration Manual, (APH7W), 04/2009, 6SN1197-0AD72-0BP0
AZ
in operation depends on the motor mounting position.
AZ
Shaft end facing downwards
Mechanical properties of the motors
3.4 Radial and axial forces
Shaft end facing upwards
73