Patent classifications
F16H2059/6869
Hydrostatic breaking concept
Hydrostatic transmission and method for decelerating a hydrostatic transmission with a closed hydraulic fluid circuit, in which a hydraulic pump drivable by a drive engine and a hydraulic motor are arranged and connected fluidly to one another through two working lines. Alternately depending on the operational mode and on the conveying direction of the hydraulic pump, one working line is the low pressure line and the other one is the high pressure line. The hydraulic pump as well as the hydraulic motor are adjustable in their respective displacement volumes by means of a control unit. The hydraulic motor comprises a housing in which a hydrostatic drive mechanism having an inlet and an outlet is arranged. In a connecting line connecting the outlet and the inlet a pressure control valve is arranged, which can be flown through in direction to the inlet. The pressure control valve opens if the high pressure present at the outlet exceeds a predetermined pressure limit of the pressure relief valve. During the coasting operation of the hydrostatic transmission the displacement of the hydraulic pump and/or of the hydraulic motor are adjustable by means of the control unit in function of the speed of the drive motor or of the speed of the hydraulic pump.
Method of using feedforward compensation based on pressure feedback for controlling swash plate angle in a hydrostatic power unit of a continuously variable transmission
A swash plate angle for a hydrostatic power unit of a continuously variable hydromechanical transmission is determined using a feedforward compensation term, to reduce reliance on closed loop control. The feedforward term is based on knowledge of the hydrostatic power unit determined as a function of knowledge of certain parameters, including, but not limited to, hydrostatic power unit pressure, swash plate angle, desired hydrostatic power unit ratio, and pump speed.