Hitachi Construction Machinery Co., Ltd.

Hayato Masuda

Takeshi Shibukawa

Motoki Sato

Masahiko Ono

Tomoharu Morita

Makoto Henmi

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

A dump truck has a flange on an inner peripheral wall of a spindle. The flange arranges a support bearing for supporting a shaft. The spindle is formed of a chassis-side member and a reduction gear unit-side member joined together by welding. The chassis-side member is fixed on a chassis of the dump truck, and the reduction gear unit-side member is located closer to a side of the reduction gear unit than the chassis-side member. The reduction gear unit-side member is located on a side of an outer periphery of the shaft portion, where a distance to a coupling between the motor and shaft and a distance to a first sun gear between the reduction gear unit and shaft are equal to each other. On an inner peripheral wall of the reduction gear unit-side member, the flange is cast together with the reduction gear unit-side member.

Running device for dump truck

A travel assembly is provided with a cylindrical spindle for being fixed on a body of a working vehicle, a rotary shaft arranged extending in an axial direction through the spindle and rotationally drivable by a driving source, a rim rotatably arranged on a side of an outer periphery of the spindle to permit mounting of a wheel thereon, a planetary gear reduction mechanism for transmitting rotation of the rotary shaft to the rim at a reduced speed, a bearing rotatably supporting the rotary shaft via a sleeve integrally fitted on the rotary shaft, and a retainer holding the bearing in place. A lube oil pipe for feeding lube oil to the rotary shaft is held in place by the retainer. The lube oil pipe branches within the retainer to form an oil passage. The oil passage has an opening through which the lube oil can be fed to rolling elements in the bearing.

Travel assembly

A travel assembly, for example, suited for arrangement on a vehicle such as a mining dump truck, is provided with a travel motor, a planetary speed reduction mechanism for transmitting rotation of the travel motor at a lower rotational speed, a spindle forming an axle, and a wheel supported on the spindle via a tapered roller bearing and rotatable by the planetary speed reduction mechanism. The planetary speed reduction mechanism includes a sun gear rotatable by rotation of a shaft of the travel motor, planet gears for rotating the wheel in response to rotation of the sun gear, and a carrier for holding the planet gears. The travel assembly is provided with a spline connection connecting the spindle and the carrier with each other and an oil passage for guiding internal lube oil of the planetary speed reduction mechanism to the spline connection.

Wheels of a dump truck are each provided with a travel assembly for transmitting an output of an electric motor to the wheel via a reduction gear unit. The travel assembly is provided with a cooling circuit for cooling lube oil. The cooling circuit has an oil cooler and a recovery oil passage for guiding lube oil from a side of the gear unit to the cooler. The recovery oil passage has an intra-spindle recovery line inserted on a side of an inner periphery of a spindle, a suction pipe extending from the recovery line to a space surrounded by the spindle, the wheel and two spindle-supporting bearings, and communication holes formed in the wheel to communicate the side of the reduction gear unit with the space.

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Tsuchiura, Japan

Hayato Masuda