Piston-cylinder unit and method for operating same
AssigneeSchaeffler Technlogies AG & Co. KG
InventorsAlexander Dreher, Marco Treder
Life of this patent
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Abstract
A piston-cylinder unit (40) for hydraulic actuation of a clutch in a vehicle, including a piston (42), a cylinder (41) and a sealing element (43). The piston cylinder unit is fluidically linked to a fluid circuit (44), the piston (42) is axially displaceable in the cylinder, and the sealing element is arranged sealingly between the piston and the cylinder, characterized in that a sensor is arranged in or on the piston-cylinder unit, by which sensor a pressure can be measured in the interior of the piston-cylinder unit and/or in the fluidically linked fluid circuit. A method for operating the piston-cylinder unit is also provided.
Claims5
A piston-cylinder unit, comprising a piston, a cylinder, and a sealing element, wherein the piston-cylinder unit is fluidically linked to a fluid circuit, the piston is displaceable axially in the cylinder, and the sealing element is arranged sealingly between the piston and the cylinder, and a sensor arranged in or on the piston-cylinder unit that measures a pressure in at least one of an interior of the piston-cylinder unit, or the fluidically linked fluid circuit,
- wherein the piston is displaceable by a positioning element, and an adjustment speed of the piston is specified by the positioning element as a function of a value output by the sensor, and
- the sensor outputs a constant signal that has an amplitude that is independent of the value output by the sensor when there is a change from the overpressure to the underpressure or when there is a change from the underpressure to the overpressure.
A method for adjusting the piston of the piston-cylinder unit for the actuation of a clutch, the piston-cylinder unit including a piston, a cylinder, and a sealing element,
- wherein the piston-cylinder unit is fluidically linked to a fluid circuit, the piston is displaceable axially in the cylinder, and the sealing element is arranged sealingly between the piston and the cylinder, and a sensor arranged in or on the piston-cylinder unit that measures a pressure in at least one of an interior of the piston-cylinder unit, or the fluidically linked fluid circuit,
- the method comprising:
- detecting the pressure in the at least one of the interior of the piston-cylinder unit, or the fluidically linked fluid circuit by using the sensor and signaling a measured value,
- converting the measured value into an adjustment setting for a positioning element,
- specifying an adjustment speed for the piston by the positioning element, and
- adjusting the piston by the positioning element,
- wherein the adjustment setting for the positioning element is formed by the measured value weighted with a changing correction factor, and the correction factor is greater for a greater value of the underpressure measured by the sensor.
Dependencies are inferred from the claim text.