Bearing monitoring device of railcar

1. A bearing monitoring device of a railcar, the railcar being constituted by coupling a plurality of cars including carbodies and bogies, the bearing monitoring device comprising:

bearing temperature sensors provided at the respective bogies and configured to directly or indirectly detect temperatures of bearings of the bogies;

at least one state sensor provided at at least one of the carbodies of the plurality of cars and configured to output data pieces corresponding to loads or rotating speeds of the bearings; and

a storage unit provided at at least one of the carbodies of the plurality of cars and configured to receive the data pieces from the at least one state sensor, and store data pieces of signals detected by the bearing temperature sensors and the data pieces received from the at least one state sensor.

2. The bearing monitoring device according to claim 1 , further comprising a diagnostic unit configured to diagnose states of the bearings based on the data pieces stored in the storage unit.

3. The bearing monitoring device according to claim 2 , wherein the diagnostic unit diagnoses the states of all the bearings of the bogies.

4. The bearing monitoring device according to claim 2 , wherein:

the at least one state sensor includes an air spring pressure sensor configured to detect an internal pressure value of an air spring interposed between the carbody and the bogie; and

the diagnostic unit calculates the loads of the bearings from the internal pressure value of the air spring detected by the air spring pressure sensor and diagnoses the states of the bearings based on the loads and the temperatures.

5. The bearing monitoring device according to claim 4 , wherein:

the plurality of cars include

a first car including a first carbody and a first bogie, and

a second car including a second carbody and a second bogie; and

the storage unit is provided at the first carbody,

the bearing monitoring device further comprising:

a first wireless transmitter provided at the first bogie and configured to wirelessly transmit the signal containing a temperature information piece detected by the bearing temperature sensor provided at the first bogie;

a second wireless transmitter provided at the second bogie and configured to wirelessly transmit the signal containing a temperature information piece detected by the bearing temperature sensor provided at the second bogie; and

a wireless receiver provided at the first carbody and configured to receive the signals wirelessly transmitted from the first wireless transmitter and the second wireless transmitter and be communicable with the storage unit, wherein

the diagnostic unit determines an internal pressure value of an air spring of the second car by using the internal pressure value of the air spring of the first car detected by the air spring pressure sensor provided at the first carbody.

6. The bearing monitoring device according to claim 2 , wherein:

the at least one state sensor includes an acceleration sensor configured to detect car traveling direction acceleration; and

the diagnostic unit calculates the rotating speeds of the bearings from the car traveling direction acceleration detected by the acceleration sensor and diagnoses the states of the bearings based on the rotating speeds and the temperatures.

7. The bearing monitoring device according to claim 6 , wherein:

the acceleration sensor and the storage unit are accommodated in one casing; and

the casing is attached to the carbody.

8. The bearing monitoring device according to claim 1 , further comprising an ambient temperature sensor provided at at least one of the carbodies of the plurality of cars and configured to detect an ambient temperature, wherein

the storage unit stores a data piece of a signal detected by the ambient temperature sensor.

9. The bearing monitoring device according to claim 8 , wherein:

the storage unit is arranged under a floor of the carbody; and

the ambient temperature sensor is arranged lower than the storage unit.