
B-65232EN/03 DESCRIPTIONS FOR FANUC AC SERVO MOTOR β series 2.NOTES ON USE
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(5) Shaft attachment section requirements
The shaft of the motor has an oil seal to prevent foreign matter
such as oil from entering the motor. Given that motors tend to be
used in a wide range of environments, however, protection
against oil penetration cannot always be perfect. Therefore,
always observe the following precautions when using these
motors.
• When oil bath lubrication is provided for the gear
engagement, for example, the oil level must be below the
lip of the oil seal (where the shaft sticks to the oil seal). Set
the oil level so that oil merely splashes the lip.
• Thus, as the shaft rotates, the oil seal can repel oil. If,
however, pressure is applied continuously while the shaft is
stopped, oil may penetrate the lip.
• When the shaft is always immersed in oil, for example,
under the condition that the motor is to be used with the
shaft oriented vertically a special design is required. For
example, another oil seal could be installed on the machine
side, and a drain provided so that oil penetrating that seal
can drain off.
• When grease is used for lubrication, the oil seal
characteristics are usually lost.
In either case, ensure that no pressure is applied to the oil seal
lip.
Oil level
The motor shaft oil seal diameter is as shown below.
Motor model Oil seal diameter
βM0.2/4000, βM0.3/4000 φ8mm
βM0.4/4000, βM0.5/4000, βM1/4000 φ14.9mm
β1/3000, β2/3000 φ15mm
β3/3000, β6/2000 φ24mm