A machine tool controller according to an embodiment of the present invention, for controlling a spindle and a feed axis, includes a motor temperature obtaining unit for obtaining and outputting the winding temperature of a spindle motor as a motor temperature; an inverter temperature obtaining unit for obtaining and outputting the temperature of an inverter that drives the spindle motor as an inverter temperature; a motor temperature comparator for comparing the outputted motor temperature with an overheat temperature for the motor; an inverter temperature comparator for comparing the outputted inverter temperature with an overheat temperature for the inverter; and an overheating assessment unit for imposing a restriction on the output of the spindle motor according to the smaller one of the differences between the motor temperature and the overheat temperature for the motor and between the inverter temperature and the overheat temperature for the inverter.

A machine tool controller according to an embodiment of the present invention, for controlling a spindle and a feed axis, includes a motor temperature obtaining unit for obtaining and outputting the winding temperature of a spindle motor as a motor temperature; an inverter temperature obtaining unit for obtaining and outputting the temperature of an inverter that drives the spindle motor as an inverter temperature; a motor temperature comparator for comparing the outputted motor temperature with an overheat temperature for the motor; an inverter temperature comparator for comparing the outputted inverter temperature with an overheat temperature for the inverter; and an overheating assessment unit for imposing a restriction on the output of the spindle motor according to the smaller one of the differences between the motor temperature and the overheat temperature for the motor and between the inverter temperature and the overheat temperature for the inverter.

A motor-driven machine tool unit having a stator unit and at least one rotor unit having a rotor shaft that is rotatable about an axis of rotation. The rotor unit includes at least one first bearing unit arranged in the end region of a tool and/or workpiece receptacle, and a second bearing unit arranged at the opposite end region for mounting the rotor shaft in the stator unit. At least one electrical power transmission unit for transmitting electrical power between the stator unit and the rotor unit is provided. The problem addressed by the invention is that of better satisfying the increasing demands on modern machine tools or machine tool units. This problem is solved by the electrical power transmission unit is arranged in the end region opposite the tool and/or workpiece holder and/or on the second bearing unit.

A motor-driven machine tool unit having a stator unit and at least one rotor unit having a rotor shaft that is rotatable about an axis of rotation. The rotor unit includes at least one first bearing unit arranged in the end region of a tool and/or workpiece receptacle, and a second bearing unit arranged at the opposite end region for mounting the rotor shaft in the stator unit. At least one electrical power transmission unit for transmitting electrical power between the stator unit and the rotor unit is provided. The problem addressed by the invention is that of better satisfying the increasing demands on modern machine tools or machine tool units. This problem is solved by the electrical power transmission unit is arranged in the end region opposite the tool and/or workpiece holder and/or on the second bearing unit.

A motor controller includes: a rotation speed estimating unit that estimates a rotation speed of a motor on the basis of current information and primary frequency information of the motor; a proximity switch that outputs an ON signal when a portion of a rotating body of the motor is in proximity and outputs an OFF signal when a portion of the rotating body of the motor is not in proximity; a rotation speed computing unit that computes a rotation speed of the motor on the basis of the ON signal and the OFF signal; and a state determining unit that determines whether a present state is a speed attainment state and whether a present state is a speed zero state on the basis of a rotation speed estimation value estimated by the rotation speed estimating unit and a rotation speed computation value computed by the rotation speed computing unit.

A motor controller includes: a rotation speed estimating unit that estimates a rotation speed of a motor on the basis of current information and primary frequency information of the motor; a proximity switch that outputs an ON signal when a portion of a rotating body of the motor is in proximity and outputs an OFF signal when a portion of the rotating body of the motor is not in proximity; a rotation speed computing unit that computes a rotation speed of the motor on the basis of the ON signal and the OFF signal; and a state determining unit that determines whether a present state is a speed attainment state and whether a present state is a speed zero state on the basis of a rotation speed estimation value estimated by the rotation speed estimating unit and a rotation speed computation value computed by the rotation speed computing unit.

A motor controller includes: a primary frequency control unit that generates a primary frequency command value based on current information of an induction motor and limits the primary frequency command value based on a maximum primary frequency; a rotation speed estimating unit that estimates a slip frequency based on the current information of the induction motor and estimates a rotation speed based on the estimated slip frequency estimation value and the primary frequency command value; a proximity switch that outputs an ON signal or OFF signal when a portion of a rotating body of the induction motor is in proximity or not in proximity; a rotation speed computing unit that computes a rotation speed based on the ON signal and the OFF signal; and a maximum primary frequency computing unit that computes the maximum primary frequency based on the rotation speed computation value.

A motor controller includes: a primary frequency control unit that generates a primary frequency command value based on current information of an induction motor and limits the primary frequency command value based on a maximum primary frequency; a rotation speed estimating unit that estimates a slip frequency based on the current information of the induction motor and estimates a rotation speed based on the estimated slip frequency estimation value and the primary frequency command value; a proximity switch that outputs an ON signal or OFF signal when a portion of a rotating body of the induction motor is in proximity or not in proximity; a rotation speed computing unit that computes a rotation speed based on the ON signal and the OFF signal; and a maximum primary frequency computing unit that computes the maximum primary frequency based on the rotation speed computation value.

A motor control device for a machine tool having a plurality of axes includes a plurality of motor control units that control motors; an abnormality detection unit provided for at least one of the motor control units and configured to output an abnormality detection signal upon detecting an abnormality with respect to the axis driven by the motor controlled by the motor control unit provided with the abnormality detection unit; a safety operation control unit provided for a motor control unit that is not the motor control unit provided with the abnormality detection unit, the safety operation control unit configured to control the motor upon receiving the abnormality detection signal in such a way that the tool comes out of contact with the workpiece; and a communication unit that transmits the abnormality detection signal outputted by the abnormality detection unit to the safety operation control unit.

A motor control device for a machine tool having a plurality of axes includes a plurality of motor control units that control motors; an abnormality detection unit provided for at least one of the motor control units and configured to output an abnormality detection signal upon detecting an abnormality with respect to the axis driven by the motor controlled by the motor control unit provided with the abnormality detection unit; a safety operation control unit provided for a motor control unit that is not the motor control unit provided with the abnormality detection unit, the safety operation control unit configured to control the motor upon receiving the abnormality detection signal in such a way that the tool comes out of contact with the workpiece; and a communication unit that transmits the abnormality detection signal outputted by the abnormality detection unit to the safety operation control unit.