US Patent No. 9,092,027

CONTROL APPARATUS OF MACHINE TOOL INCLUDING FEED SHAFT MOTOR AND MAIN SPINDLE MOTOR


Patent No. 9,092,027
Issue Date July 28, 2015
Title Control Apparatus Of Machine Tool Including Feed Shaft Motor And Main Spindle Motor
Inventorship Tadashi Okita, Yamanashi (JP)
Daisuke Tajima, Yamanashi (JP)
Assignee FANUC CORPORATION, Yamanashi (JP)

Claim of US Patent No. 9,092,027

1. A control apparatus of a machine tool including a feed shaft motor for driving a feed shaft and a main spindle motor for
driving a main spindle, the control apparatus comprising:
a converter for performing a bi-directional power conversion between an AC voltage of an AC power supply side and a DC voltage
at a DC link being a DC side;

a feed shaft motor inverter for performing a bi-directional power conversion between the DC voltage at the DC link and an
AC voltage of the feed shaft motor side to supply drive power to the feed shaft motor;

a main spindle motor inverter for performing a bi-directional power conversion between the DC voltage at the DC link and an
AC voltage of the main spindle motor side to supply drive power to the main spindle motor;

a power outage detection unit for detecting an occurrence and non-occurrence of a power outage of the AC power supply side
of the converter;

a voltage detection unit for detecting the DC voltage at the DC link; and
a control unit for outputting a feed shaft motor deceleration command for controlling the feed shaft motor inverter to decelerate
the feed shaft motor upon detection of a power outage by the power outage detection unit, wherein, upon detection of the power
outage by the power outage detection unit, the control unit outputs a main spindle motor acceleration command for controlling
the main spindle motor inverter to accelerate the main spindle motor when a DC voltage detected by the voltage detection unit
is greater than a predetermined upper limit value and a main spindle motor deceleration command for controlling the main spindle
motor inverter to decelerate the main spindle motor when the DC voltage detected by the voltage detection unit is less than
a predetermined lower limit value which is lower than the predetermined upper limit value.