Driven wheel unit including an axially compact two-speed planetary gear drive assembly

摘要

A driven wheel unit includes an electric motor coupled to a two-speed, three stage planetary drive assembly and has a width dimensioned for traveling between rows of crop. A wheel hub is supported on an outer surface of a fixed housing by large diameter wheel bearings surrounding both a motor-containing cavity and an adjacent cavity containing first and second planetary stages. Nested radially and surrounding the two planetary stages are two SAHR disc clutches including pistons engaging inner and outer surfaces of a compact piston guide member. The third stage planet carrier defines a cap and is fixed to an axially outer end of the wheel hub. A third stage ring gear has an outside diameter approximately equal to that of the wheel bearings and has an inside diameter fixed to the housing by a planar, annular wheel bearing retainer plate that is fixed to an end of the housing.

主权项

1. A drive wheel unit for use with a vehicle intended for operation wherein a pair of the drive wheel units are driven between rows of plants separated from each other by a predetermined distance as narrow as 20 inches (508 mm), with the wheel units including a circular rim carrying a tire rotatable about a central rotation axis and having an axial width which does not exceed said predetermined distance, the drive wheel unit comprising:
a fixed housing located along said central rotation axis and having an outer cylindrical surface arrangement configured for, and carrying, a pair of roller thrust bearings in axial alignment with each other along said rotation axis, the housing further including an internal cavity arrangement configured for, and receiving, a drive motor having an output shaft located along said central rotation axis and coupled to a first stage of a two-speed, three stage planetary gear arrangement; a wheel mounting hub being supported for rotation about said outer cylindrical surface of said fixed housing by said pair of roller thrust bearings and said planetary gear arrangement having a third stage planet carrier mounted to said hub and serving as a cap for said hub and for said planetary transmission arrangement; said pair of roller thrust bearings being of a relative large diameter and encircling said first and second stages of said planetary transmission arrangement; and said drive motor including a housing with an axial distance between an axially inner surface of said housing and an axially outer surface of said hub being approximately equal to said axial width of said tire.