Hitachi, Ltd.

Hitachi Construction Machinery Co., Ltd.

Makoto Henmi

Norio Takeda

Motoki Sato

Tomoaki Yamashita

Masahiko Ono

Hayato Masuda

Tomoharu Morita

Shinichi Sekido

Tatsuya Ono

An abnormality diagnosis device for a planetary gear speed reducer includes a second vibration sensor attached to a housing of a hydraulic motor having an output shaft coupled to the planetary gear speed reducer. A controller computes a peak frequency Fm of the hydraulic motor and a speed of rotation of the hydraulic motor on the basis of second vibration data acquired through the second vibration sensor, compute, on the basis of the computed speed of rotation, the number of a plurality of gears included in the planetary gear speed reducer, and the number of teeth of each of the gears, characteristic frequencies fd of the plurality of gears, and determines presence or absence of abnormality in the plurality of gears on the basis of the peak frequency Fm of the hydraulic motor and amplitudes at the characteristic frequencies fd of first vibration data acquired through a first vibration sensor attached to the planetary gear speed reducer.

Abnormality diagnosis device for planetary gear speed reducer and construction machine

There are provided a rolling bearing fatigue state prediction device and a rolling bearing fatigue state prediction method capable of highly accurately predicting a fatigue state of a rolling bearing even when a direction of a load applied to a rolling bearing changes. A rolling bearing fatigue state prediction device includes a load measurement unit for determining a magnitude and a direction of a bearing load applied to a rolling bearing supporting a rotating body, a load applied region identification unit for identifying a region to which a load is applied in a circumferential region of the rolling bearing, and a fatigue state prediction unit for predicting a fatigue state of the rolling bearing based on the obtained magnitude of the load and the identified load applied region.

Rolling bearing fatigue state prediction device and rolling bearing fatigue state predicting method

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Tokyo, Japan

Makoto Henmi