
B–65142E/04
2. PRECAUTIONS ON USEDESCRIPTIONS FOR THE α series
17
The allowable axis load of the motor shaft is as follows.
Motor model Radial load Axial load
Front bearing
(reference)
α1/2
αM2/2.5
25 [kgf] 8 [kgf] 6003
α3/6
αM6/9
αL6/9
αC3/6
α3/6HV
αM6/9HV
70 [kgf] 20 [kgf] 6205
α12/22/30/40
αM22/30/40/40 (with fan)
αL25/50
αC12/22
α12/22/30/40HV
αM22/30/40HV
450 [kgf] 135 [kgf] 6208
α65/100/150 900 [kgf] 250 [kgf] 6312
α300/400 1200 [kgf] 200 [kgf] NU2214
α1000 1400 [kgf] 200 [kgf]
6317 Combina-
tion bearing
The above values are the reference assuming the use as a feed axis on the
typical machine tool.
D The allowable radial load is the value when a load is applied to the
shaft end. It indicates the total continuous force applied to the shaft
in some methods of mounting (e.g, belt tension) and the force by load
torque (e.g., moment/pulley radius).
D The belt tension is critical particularly when a timing belt is used. Too
tight belt causes breakage of the shaft or other fault.
Belt tension must be controlled so as not to exceed the limits calculated
from the permissible radial load indicated above.
D In some operation conditions, the pulley diameter and the gear size
need to be checked. For example, when using the model α3 with a
pulley/gear with the radius of 2.5cm or less, the radial load at the
occurrence of 180kg⋅cm torque will exceed 70kg. In the case of timing
belt, as the belt tension is added to this value, it is thus necessary to
support the shaft end.
D Actually, when using a timing belt, a possible fault like a broken shaft
can be prevented by positioning the pulley as close to the bearing as
possible.
D When there is a possibility of a large load, the machine tool builder
needs to examine the life by referring to the shaft diameter, bearing,
etc.
D Since the standard single row deep groove ball bearing is used for the
motor bearing, a very large axial load can not be used. Particularly,
when using a worm gear and a helical gear, it is necessary to provide
another bearing.
D The motor bearing is generally fixed with a C-snap ring, and there is
a small play in the axial direction. When this play influences the
positioning in the case of using a worm gear and a helical gear, for
example, it is necessary to fix it with another bearing.
2.4
AXIS LOAD