
B-65282EN/05 11.SPINDLE-RELATED DETECTORS
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11.1.3 Installation Conditions and Notes
(1) Connection method
Two methods of connecting an α position coder or α position
coder S with the spindle are available.
(a) One method connects a position coder to the rear part of the
spindle by using a flexible joint. In this case, spindle
rotation is transferred to the position coder accurately, so
that the positioning precision of the position coder becomes
high. In this case, however, the location where the position
coder can be installed is limited, so the mechanical section
may need to be modified.
(b) With the other method, as shown below, a shaft for holding
a pulley is fitted onto the shaft of the position coder, and
the shaft is held by two bearings. The pulley of the position
coder is connected via a timing belt with the pulley attached
to the spindle.
This method is generally used to connect a conventional position
coder with the spindle. In this case, however, pay attention to the
following:
<1> If there is backlash between the shaft for holding a pulley
and the shaft of the position coder, fretting can occur on the
shaft of the position coder, or the key can become loose,
causing the positioning precision of the position coder to
degrade. So, ensure such a fitting tolerance that there is no
backlash between the shaft of the position coder and the
shaft for holding a pulley and between the key and the key
groove.
<2> If the periphery of the pulley of the position coder is
eccentric relative to the axis center of the shaft of the
position coder, or the periphery of the pulley fitted onto the
shaft is eccentric relative to the axis center of the shaft, the
positioning precision of the spindle degrades in proportion
to the magnitude of eccentricity. So, minimize these
eccentricities.
BearingKey
Pulley
Key
Shaft
Mounting
late
α position coder
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