Aisin Aw Co., Ltd.

Yukio Yamada

Hirotaka Yata

Tatsuki Uchida

A working oil accumulated in oil reservoirs is supplied to electric motor cooling oil passages and lubricating oil passages in well-balanced manner all during the time of normal and very low temperatures in an electric drive unit. The electric drive unit comprises an electric motor and a feed oil passage, through which a working oil for cooling and lubrication is supplied to respective mechanisms of a drive unit including the electric motor, in a drive unit body. An oil reservoir communicates with a working oil supply source and is provided in an upper area of the drive unit body. A weir is provided between a first reservoir, which communicates the oil reservoir to the working oil supply source and communicated to small flow-rate discharge oil passages, and a second reservoir communicates with a large flow-rate discharge oil passage. Because discharge of the working oil to the large flow-rate discharge oil passage is thereby restricted until the working oil reaches a level to go over the weir, setting of an orifice on a side of the large flow-rate discharge oil passage in conformity to flowability of the working oil at the time of very low temperature makes it possible to prevent the working oil from excessively flowing to the side of the large flow-rate discharge oil passage at the time of normal temperature, while preventing a pressure rise in the oil reservoirs at the time of very low temperature.

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Anjo, Japan

Yukio Yamada