Patent ID: 9551416
Date: 2017-01-24
CPC Classifications: F16H,Y10T

Claim:
1. A method for changing gear stages in a transmission equipped with a hydrostatic transmission and a downstream manual transmission, the hydrostatic transmission having a hydraulic pump with a displacement adjustable by a first adjusting device and a hydraulic motor with a displacement adjustable by a second adjusting device whereby the the hydraulic pump and the hydraulic motor are connected to each other in a closed hydraulic circuit, comprising the following method steps: detecting of a shift request; triggering of the hydrostatic transmission and the downstream manual transmission in order to change a gear stage of the downstream manual transmission, wherein triggering the hydrostatic transmission includes triggering the first adjusting device so that the pressure in the hydraulic circuit remains essentially constant and triggering the second adjusting device so that the rotation speed of the hydraulic motor corresponds to a target rotation speed; detecting whether an intended gear stage to be engaged by the gear stage change has been successfully engaged; engaging an original gear stage if the intended gear stage has not been successfully engaged; and renewing the triggering of the downstream manual transmission in order to engage the intended gear stage, wherein after a limited number of successive unsuccessful attempts greater than one to shift into the intended gear stage is detected, the transmission is shifted back into the original gear stage and a new attempt to shift into the intended gear stage is only executed if a new shift request is detected.