Tuff Torq Corporation

Other

Kerwyn Stoll

Robert Abend

Norihiro Ishii

In a hydraulic transmission for driving and steering wheels of a vehicle, which has at least a first pair of laterally disposed wheels, a first hydraulic pump is operatively connected to a driving source with inlet/outlet ports respectively and fluidly connected to a high pressure side and a low pressure side of the parallel fluid passages. A second hydraulic pump is operatively connected to the driving source and having inlet/outlet ports respectively and fluidly connected to high and low pressure sides of the fluid passages between the second pair of hydraulic motors. The first hydraulic pump is of a variable displacement type that varies the amount of hydraulic fluid to be discharged and supplied, based upon the displacement amount of a first output adjustment member, in which the displacement amount is varied by operating the first output adjustment member via a driving-speed operation member. The second hydraulic pump is of a variable displacement type that varies the amount of hydraulic fluid to be discharged and sucked, based upon the displacement amount of a second output adjustment member, in which the displacement amount is varied by operating the second output adjustment member via a steering operation member. Rotational power is input from each of the second pair of hydraulic motors to a corresponding one of the output shafts of the first pair of hydraulic motors by a magnitude corresponding to the operational amount of the steering operation member in a different rotational direction from each other.

Hydraulic transmission for driving and steering wheels

A driving apparatus for speed changing and steering of a vehicle consists of a first driving unit for speed changing in advancing and reversing and a second driving unit for steering, which are arranged in a longitudinal row and are attached to a vehicle chassis. Each of the first driving unit and the second driving unit has a common structure, which comprises a housing and an HST and left and right differential output shafts contained in the housing. A left first differential output shaft and a left second differential output shaft are connected with each other so as to be rotated in the same direction, and a right first differential output shaft and a right second differential output shaft are connected with each other so as to be rotated in opposite directions. Both first and second HSTs of the first driving unit and a second driving unit receives power from engine through a common single belt. A movable swash plate of a hydraulic pump of the first HST is connected to a speed change pedal and a movable swash plate of a hydraulic pump of the second HST is connected to a steering wheel.

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Mattoon, IL, United States of America

Kerwyn Stoll