Patent ID: 6260440
Filing Date: 2001-07-17
Classification: F16H,Y10T

Abstract:
A transmission assembly comprising:a hydrostatic transmission having a variable displacement hydraulic device which controls a ratio of an input speed to an output speed of the hydrostatic transmission;a mechanical transmission coupled to the hydrostatic transmission and having a first range and a second range; andan output shaft driven by one or more of the hydrostatic transmission and the mechanical transmission which causes a work machine to move at a travel speed, wherein:a motor speed ratio is the ratio of the output speed to the input speed,a travel speed ratio is the ratio of the travel speed to the input speed,the torque through the hydrostatic transmission reverses when the mechanical transmission shifts from the first range to the second range,a synchronous travel speed ratio is the travel speed ratio which produces the same motor speed ratio in both the first gear range and the second gear range,an equal displacement travel speed ratio is the travel speed ratio at which a displacement of the variable displacement device in the second gear range is the same as the displacement in the first gear range,a travel speed ratio differential is a difference between the synchronous travel speed ratio and the equal displacement travel speed ratio, andthe shift from the first range to the second range is initiated at a travel speed ratio which varies from the equal displacement travel speed ratio by less than eighty percent of the travel speed ratio differential.