Hydraulic control arrangement for an automatic transmission
AssigneeDaimler AG
InventorsJoerg Schindler, Michael Baraga, Markus Brandenburg, Henrik Kalczynski, Thomas Kull
Life of this patent
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Abstract
In a hydraulic control arrangement for an automatic transmission of a motor vehicle having a parking lock activation system wherein operating fluid is supplied via a parking lock slide valve to a first parking lock pressure chamber for moving a parking lock-up piston in one direction into a locking position or moving the parking lock piston in an opposite direction, whereby operating fluid is released from the first parking lock pressure chamber via a discharge slide valve by way of which the first parking brake pressure chamber is connected to a tank for releasing the parking lock-up.
Claims10
A hydraulic control arrangement for an automatic transmission of a motor vehicle with a parking lock activating system (68) which has a parking lock slide valve (80) and a parking lock piston-cylinder unit (69) with a parking lock piston (70) and a first parking lock pressure chamber (73), whereby, by supplying operating fluid via the parking lock slide valve (80) into the first parking lock pressure chamber (73), the parking lock piston (70) can be displaced in a first activating direction (71) and in case of a displacement of the parking lock piston (70) in a second activating direction (72) contrary to the first activating direction (71), operating fluid is removed from the first parking lock pressure chamber (73), the parking lock activating system (68) comprising a discharge slide valve (81), by way of which the first parking lock pressure chamber (73) can be connected to a tank (13), the discharge slide valve (81) being arranged between the parking lock slide valve (80) and the parking lock piston-cylinder unit (69) and having at least two positions,
- a fill position, in which a parking lock connecting line (82) extending between the parking lock slide valve (80) and the discharge slide valve (81) is connected via the discharge slide valve (81) to the first parking lock pressure chamber (73), and
- a discharge position in which the first pressure chamber (73) is connected via the discharge slide valve (81) to the tank (13) and the parking lock connecting line (82) is closed by the discharge slide valve (81), wherein
- as control pressure for a switchover between the two positions of the discharge slide valve (81), pressure present in said parking locking connecting line (82) between the parking lock slide valve (80) and the discharge slide valve (81) is supplied to the discharge slide valve (81).
Dependencies are inferred from the claim text.