Mechanical properties of the motors
3.4 Radial and axial forces
1PM6/1PM4 Hollow-Shaft Motors for Main Spindle Drives
50
Configuration Manual, PPMS, 04/2008, 6SN1197-0AD23-0BP0
Reducing the bearing change intervals
The bearing change intervals t
LW
must be reduced for:
●
Vertical mounting position (reduced by up to 50%)
●
Operation predominantly above 75% of the limit speed n
max
●
High vibration and surge loads
●
Frequent reversing operation
●
Higher bearing temperatures > +85 °C
3.4
Radial and axial forces
Radial force
In order to guarantee perfect operation, the radial force may not exceed 200 N.
Axial force
The axial force acting on the locating bearings comprises the following components:
●
Operational axial force
–
Axial forces acting externally on the motor
–
Axial forces from the coolant pressure of the coolant fed through the rotary gland
●
Force due to pre-loaded bearings
●
Possible force due to the rotor weight when the motor is vertically mounted
This results in a maximum axial force that is a function of the direction.
CAUTION
Carefully observe the axial force as a result of the effective hydraulic diameter (surface) of
the rotary gland.
Force F [N] = A (surface m
2
) x p (coolant pressure in N/m
2
); 1 bar = 10
5
N/m
2
For axial forces in the direction of the motor, the spring-loading of the bearings can be
overcome so that the rotor moves according to the axial bearing play (up to 0.2 mm). The
permissible axial force F
AZ
in operation depends on the motor mounting position.