Determination device

A determination device comprising:

• a probe configured to induce an eddy current in a bearing by applying an alternating magnetic field and detect an impedance of the bearing;
• a switch configured to transmit a measurement control signal for switching start and end of acquisition of a measurement signal of the impedance detected by the probe;
• and
• a fatigue determination unit configured to determine a degree of fatigue or a remaining life of the bearing based on the impedance of the bearing, wherein
• the fatigue determination unit includes
• a map storage unit configured to store a determination map including a relation between an impedance characteristic of the bearing and the degree of fatigue or the remaining life of the bearing,
• a measurement switching unit configured to switch between a measurement execution state and a measurement non-execution state based on a state of the measurement control signal,
• a data holding unit configured to hold the measurement signal in the measurement execution state,
• an impedance characteristic calculation unit configured to calculate the impedance characteristic of the bearing based on the held measurement signal, and
• a determination unit configured to determine the degree of fatigue or the remaining life of the bearing based on the impedance characteristic of the bearing and the determination map,
• the probe includes
• a substantially columnar probe main body configured to detect the impedance of the bearing by coming into contact with a measurement target surface of the bearing,
• a housing having therein a sliding hole extending in an axial direction, the housing being configured to accommodate the probe main body disposed in the sliding hole in a manner of allowing the probe main body to slide in the axial direction,
• an abutting portion provided at a distal end portion of the housing and configured to abut against the measurement target surface of the bearing, and
• a biasing spring disposed in the sliding hole of the housing and configured to bias the probe main body in the axial direction with respect to the housing,
• the abutting portion includes four protrusions protruding in the axial direction, and
• when viewed from the axial direction, the four protrusions are respectively positioned at vertices of a rectangle centered on a central axis of the probe main body.