Instruction manual

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2. LINEAR SERVO MOTOR
2.1.2 Instructions on design
CAUTION
The dynamic brake can be applied to the servo Amplifier, but the coasting distance
becomes longer when the moving body is heavy or when the speed is high. It may
result in crashing into the stroke edge, which is highly dangerous. Install the anti-
crash mechanism such as an air brake or an electric/mechanical stopper such as a
shock absorber to reduce the shock of movable parts. (No linear servo motor with
an electromagnetic brake is available.)
The magnetic suction power acting between the primary side (coil) and the
secondary (magnet) is always acting even when the motor power is not turned on.
Because of this, the machine must be designed to be rigid enough to resist the
magnetic suction power and maintain the accuracy.
The running load by friction increases in proportion to the increase of the magnetic
suction power, so the design must be made to decrease as much friction as
possible, for example, by mounting guides with high accuracy.
Do not use for vertical motion applications since magnetic poles cannot be
detected with a vertical application.
Install the linear servo motor the way in which the thrust acts on the gravity center
of the movable part. When the thrust does not act on the gravity center of the
movable part, the moment is generated.
Design the mounting dimensions to be satisfied for the primary side (coil) and
secondary side (magnet).
The cables such as power cables deriving from the primary side (coil) cannot stand
the long-term flexing action. Avoid the flexing action by fixing to the movable part,
etc. Also, use the cable that stands the long-term flexing action for the wiring to the
servo amplifier.
Magnetic chips such as iron fragments can be attached to the permanent magnet
on the secondary side, which may cause a malfunction. In the environment like
this, take measures against the attachment and entry of magnetic chips.
When the linear servo motor is operated over a long term under the condition
where water for cutting or lubrication oil is splashed or where oil mist or dew
condensation occurs due to supercooling or high humidity, insulation deterioration
or other failures may be caused. Prevent the linear servo motor from oil and dust
with a cover and take measures against dew condensation.
More careful measures against oil and dust must be taken for the linear encoder
than the linear servo motor. For details, please contact the linear encoder
manufacturer individually.
The moving direction of the linear servo motor and linear encoder must be
matched. Otherwise, the motor may run out of control.
When two or more secondary side (magnet) is mounted, set the mounting screw
accumulative pitch tolerance within
0.2mm. Clearance may be left between the
secondary sides (magnets) depending on the mounting method and the numbers.
Do not hit the primary side (coil) on the stopper. The primary side may be
damaged. Design the machine so that the stopper is hit on the top table attached
to the primary side (coil).