Hydrostatic Traction Drive with a Pressure Cutoff and Method for Calibrating the Pressure Cutoff
AssigneeRobert Bosch GmbH
InventorsFranz Werner, Matthias Mueller, Michael Frasch, Ronny Herrmann, Ulrich Lenzgeiger
Life of this patent
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Abstract
A hydrostatic traction drive includes a hydraulic pump for supplying pressure medium to a hydraulic motor of the traction drive. The hydraulic pump has an actuation cylinder with at least one cylinder space and a swept volume which can be adjusted thereby. At least one electrically actuable pressure valve is provided, by means of which an actuation pressure which has an adjusting effect can be applied to the cylinder space. In addition, the traction drive has a device by means of which a pressure of the hydraulic pump can be limited by influencing the actuation pressure.
Claims16
A hydrostatic traction drive comprising:
- a hydraulic pump coupled to a drive machine and configured to supply pressure medium to a hydraulic motor, which is coupled to an output of the hydrostatic traction drive, the hydraulic pump having an actuating cylinder that includes at least one cylinder space and is configured to adjust a swept volume of the hydraulic pump;
- at least one electrically actuable pressure valve configured to apply an actuation pressure which has an adjusting effect to the cylinder space;
- and
- a device configured to limit a pressure of the hydraulic pump by influencing the actuation pressure,
- wherein the device is configured so as to limit the pressure in a controlled fashion, and the controlled limitation of the pressure is calibrated.
A method for calibrating a device of a traction drive that includes (i) a hydraulic pump coupled to a drive machine and configured to supply pressure medium to a hydraulic motor, which is coupled to an output of the hydrostatic traction drive, the hydraulic pump having an actuating cylinder, which includes at least one cylinder space and is configured to adjust a swept volume of the hydraulic pump, (ii) at least one electrically actuable pressure valve configured to apply an actuation pressure which has an adjusting effect to the cylinder space, and (iii) the device, which is configured to limit a pressure of the hydraulic pump by influencing the actuation pressure, wherein the device is configured so as to limit the pressure in a controlled fashion, and the controlled limitation of the pressure is calibrated, the method comprising:
- actuating the pressure valve with an actuation current according to a ramp function;
- sensing the pressure as a function of the actuation current;
- determining a limit actuation current which is assigned to a pressure limit of the pressure if the pressure reaches the pressure limit;
- and
- storing the pressure limit and the limit actuation current.
Dependencies are inferred from the claim text.