Hitachi Construction Machinery Co., Ltd.

Hitachi Industrial Equipment Systems Co., Ltd.

Makoto Ishijima

Seiji Ishida

Satoshi Kikuchi

Tsutomu Miyoshi

Itsuro Sawada

Shigenori Aoki

Kenta Tanigaki

A low idling controller (A) switches an idling state flag from 'clear' to 'set' upon detecting a non-operation of an operating device (). A rotational speed controller (B) switches a rotational speed command from a set rotational speed by a rotational speed command device () to a low idling rotational speed based upon the idling state flag. At this time, an engine () drives in the low idling rotational speed lower than the set rotational speed. A gate controller () stops switching of an inverter () while the low idling controller (A) is lowering a rotational speed of the engine ().

Construction machine

To uniformly cool down armature windings along the circumferential direction of a stator in a generator motor. A generator motor includes a statorfixed to the inner diameter side of a housing, a rotorrotatably supported by bearings, and armature windings wound around the teeth of a stator core. Each of bracketsprovided via the bearingshas a passagethrough which cooling oil flows and injection holeswhich communicate with the passage and inject cooling oil at positions opposite to winding ends of the armature windings. Cooling oil is injected toward the winding ends of the armature windings from the injection holesof the bracketsarranged on opposite axial sides of a shaft. In the flow rate distribution of the oil from the plurality of the injection holes, the flow rate of the oil from any of the injection holesis set to be greater as the position of the injection holeis higher above the level of the shaft. The arrangement pitch among the injection holesprovided on each of the bracketsis dense in a vertically upper portion of the bracket, and gradually sparser in a portion thereof closer to the level of shaft

Generator motor and electric vehicle using same

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Omitama, Japan

Makoto Ishijima