Feed shaft and worm gear abnormality determination system
AssigneeNikken Kosakusho Works Ltd.
InventorSusumu Mikado
Life of this patent
Estimating the term…
Abstract
A system determining whether the feed shafts are normal or abnormal, the system including: a command generation unit that moves the feed shafts in a forward direction at a predetermined speed from a lower limit value to an upper limit value of a range of feeding movement by the numerical controller; and a feed shaft abnormality determination unit that monitors a drive torque command during the movement of the feed shafts in the forward direction by the command generation unit, compares a monitoring result during the movement in the forward direction with a normal value of the drive torque command, determines that abnormality occurs when the drive torque command deviates from the normal value, and outputs the determination result.
Claims12
A feed shaft abnormality determination system mounted on a machine tool that includes a feed shaft, a servo motor that drives said feed shaft, a numerical controller that controls a drive torque of said servo motor, and an encoder that detects a speed and a feeding position of said feed shaft, the system determining whether said feed shaft is normal or abnormal, the system comprising:
- a command generation unit that moves said feed shaft in a forward direction at a predetermined speed from a lower limit value to an upper limit value of a range of feeding movement by said numerical controller;
- and
- a feed shaft abnormality determination unit that monitors a drive torque command and/or a position feedback output to said servo motor from said numerical controller during the movement of said feed shaft in the forward direction by said command generation unit, compares a monitoring result during the movement in said forward direction with a normal value of the drive torque command, determines that abnormality occurs when said drive torque command deviates from said normal value, and outputs a result of the determination,
- wherein said feed shaft abnormality determination unit calculates a feeding position of said feed shaft on the basis of said predetermined speed of said servo motor and a time from when the movement of said feed shaft in said forward direction is started until said deviation during the movement in the forward direction or on the basis of said position feedback, and outputs the calculated feeding position as an abnormal feeding position.
A worm gear abnormality determination system mounted on an indexing unit that includes a spindle which performs indexing, a worm gear provided on said spindle, a worm screw that engages with said worm gear, a servo motor that drives said worm screw, a numerical controller that controls a drive torque of said servo motor, and an encoder that detects a speed or a position of said spindle, the system determining whether said spindle is normal or abnormal, the system comprising:
- a command generation unit that rotates said spindle in a forward direction at a predetermined speed from an index angle of 0° to 360° by said numerical controller;
- and
- a worm gear abnormality determination unit that monitors a drive torque command and/or a position feedback output to said servo motor from said numerical controller during the forward rotation of said spindle by said command generation unit, compares a monitoring result during said forward rotation and a normal value of the drive torque command, determines that abnormality occurs when said drive torque command deviates from said normal value, and outputs a result of the determination,
- wherein said worm gear abnormality determination unit calculates an index angle of said spindle on the basis of said predetermined speed of said servo motor and a time from when said forward rotation of said spindle is started until said deviation or on the basis of said position feedback, and outputs the index angle associated with said drive torque command deviating from said normal value as an abnormal index angle.
Dependencies are inferred from the claim text.