Shuttle Shifting For A Continuously Variable Transmission
First Claim
1. A method of automatically operating a continuously variable hydro-mechanical transmission of a vehicle responsive to a commanded shuttle shift, comprising steps of:
- determining a start speed of operation of the transmission and a commanded end speed thereof for the shuttle shift; and
a. if the start speed and the end speed are greater than predetermined first threshold values therefor, then performing the shuttle shift by changing a direction of operation of the transmission while holding a swash plate of a hydrostatic power unit of the transmission tilted in one direction.
3 Assignments
0 Petitions
Accused Products
Abstract
A shuttle shifting method for a continuously variable transmission automatically selects a manner of shuttle shifting as a function of certain monitored conditions. As one alternative, the direction of operation of the transmission is changed prior to reducing the vehicle speed to zero, and tilt of a swash plate of the hydrostatic power unit of the transmission is held substantially constant, for achieving fast, smooth shifts at faster starting and ending vehicle speeds, without coming to a complete stop. In another alternative, for slower starting and ending speeds, or other conditions such as a temperature condition is present, the vehicle is stopped by changing swash plate angle before effecting a directional change of the transmission and the swash plate.
-
Citations
21 Claims
-
1. A method of automatically operating a continuously variable hydro-mechanical transmission of a vehicle responsive to a commanded shuttle shift, comprising steps of:
-
determining a start speed of operation of the transmission and a commanded end speed thereof for the shuttle shift; and a. if the start speed and the end speed are greater than predetermined first threshold values therefor, then performing the shuttle shift by changing a direction of operation of the transmission while holding a swash plate of a hydrostatic power unit of the transmission tilted in one direction. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A method of automatically operating a continuously variable hydro-mechanical transmission of a vehicle, comprising steps of:
-
monitoring an operator controlled input device for inputted commands indicative of a commanded shuttle shift;
thendetermining a start speed of the shift and an end speed of the shift, and, selecting a manner of performing the shuttle shift at least partially as a function of the speeds;
whereina. if the speeds are above threshold values therefor, respectively, then initiating the shuttle shift while still moving by reversing a direction of operation of an input of the transmission while maintaining a displacement and a direction of operation of a hydrostatic power unit thereof substantially constant;
orb. if at least one of the start speed and the end speed are below the threshold value therefor, then changing the displacement of the hydrostatic power unit to slow the speed of the vehicle to about zero, reversing the direction of operation of the hydrostatic power unit and changing the displacement thereof to achieve the end speed. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
-
-
18. A method of automatically operating a continuously variable hydro-mechanical transmission of a vehicle, comprising steps of:
-
monitoring an operator controlled input device for inputted commands indicative of a commanded shuttle shift; determining a start speed of the shift and an end speed of the shift; modeling a temperature of at least a first element configured and operable for holding or decelerating the vehicle during the shuttle shift; and selecting a manner of performing the shuttle shift by either changing a direction of operation of the transmission while holding a displacement of a hydrostatic power unit thereof substantially constant, or by reducing the speed to about zero and holding the vehicle while changing the direction of operation and a direction of the displacement, as a function of an analysis of the start and end speeds and the modeled temperature. - View Dependent Claims (19, 20, 21)
-
Specification