Patent attributes
A method is provided for controlling a gear ratio change in a hydrostatic drive machine. The hydrostatic drive machine includes a variable displacement pump and at least one variable displacement motor fluidly connected with the variable displacement pump. The method includes a step of determining a gear ratio rate of change corresponding to a change from a current gear ratio to a new gear ratio. Start and stop overlap gear ratios corresponding to the gear ratio rate are determined and define an overlap range. The current gear ratio is changed to the new gear ratio using electronic signals at least in part by simultaneously changing displacements of the variable displacement pump and the at least one variable displacement motor at gear ratios within the overlap range, and sequentially changing displacements of the variable displacement pump and the at least one variable displacement motor at gear ratios outside the overlap range.
