State monitoring system of gear device and state monitoring method

A state monitoring system for monitoring a state of a gear device including a plurality of gear pairs, the state monitoring system comprising

• a meshing frequency determination device configured to determine a meshing frequency of the plurality of gear pairs in one or both of a speed increaser and a speed reducer each of which is the gear device,
• the meshing frequency determination device including
• a sensor configured to detect a meshing vibration occurring in each gear pair,
• a harmonic region setting unit configured to perform setting of an upper limit of a multiple of an estimated frequency of the meshing frequency to be inspected as a harmonic region,
• an inspection frequency range setting unit in which a plurality of estimated frequency ranges to be inspected for the meshing frequency are set,
• a maximum-peak-amplitude calculation unit configured to calculate a maximum peak amplitude from the meshing vibration detected by the sensor, in the estimated frequency ranges set by the inspection frequency range setting unit and in the harmonic region set by the harmonic region setting unit, and configured to select such estimated frequencies that a difference in the maximum peak amplitude between the plurality of estimated frequency ranges, is less than or equal to a predetermined multiple, and
• a meshing frequency determination unit configured to determine an estimated frequency having a total value of maximum peak amplitudes calculated in the plurality of estimated frequency ranges, within a predetermined time, being k-th (k is a natural number) greatest among the estimated frequencies selected by the maximum-peak-amplitude calculation unit, as a meshing frequency of a gear pair having the k-th highest tooth surface speed.