
B-65382EN/02 HANDLING, DESIGN, AND ASSEMBLY 2.MECHANICAL DESIGN
- 155 -
2.12 CONSIDERATION OF MAGNETIC ATTRACTION
Although magnetic attraction varies with the magnetic gap, in the
worst case, it exerts force three times as large as the maximum force
of the motor between the coil slider and the magnet plate. This force is
constant, and is exerted even when the power to the motor is turned
off. In mechanical design, take the points below into consideration.
Design of a light and high-rigidity frame
A mechanical frame that can withstand magnetic attraction and has a
sufficiently high rigidity to maintain precision is required. On the
other hand, a light mechanical frame is required to achieve higher
acceleration. When high speed and high precision are needed, a higher
gain is required. For this purpose, consider setting a resonance
frequency as high as possible for the machine.
NOTE
Do not mount the motor on a place where the
frame bends 0.1 mm or more if the motor moves.
Repeated movement may break or chip resin,
probably resulting in a motor failure.
Low-friction design
If the friction coefficient is high, a large frictional force results due to
high magnetic attraction. Heat is generated by a large frictional force,
and a degraded efficiency results. So, a design for ensuring low
friction is needed.