Compact co-axial reduction drive unit

A reduction drive unit comprising:

• a) a differential arrangement including a differential case housing a plurality of pinion gears intermeshed with a pair of side gears;
• and
• b) a compound planetary gear arrangement including a sun gear, a fixed ring gear, a plurality of planet gears, and a carrier structure rotationally supporting the plurality of planet gears, wherein:
• i) the carrier structure is rigidly mounted to the differential case;
• ii) each of the plurality of planet gears has a first stage gear intermeshed with the sun gear and an axially offset second stage gear intermeshed with the fixed ring gear;
• and
• iii) the ring gear is axially offset from the sun gear such that the sun gear is located axially between the ring gear and the differential arrangement.

A reduction drive unit comprising:

• a) a housing assembly including a first housing part mated to a second housing part;
• b) a differential arrangement including a differential case housing a plurality of pinion gears intermeshed with a pair of side gears, the differential arrangement being housed entirely within the first housing part;
• and
• c) a compound planetary gear arrangement including a sun gear, a fixed ring gear, a plurality of planet gears, and a carrier structure rotationally supporting the plurality of planet gears, wherein:
• i) the carrier structure is rigidly mounted to the differential case;
• ii) each of the plurality of planet gears has a first stage gear intermeshed with the sun gear and a second stage gear intermeshed with the fixed ring gear;
• and
• iii) the sun gear, the fixed ring gear, and the plurality of planet gears are housed entirely within the second housing part.