Piston machine with changeable displacement
AssigneeMannesmann Rexroth GmbH
InventorsPeter Wusthof, Sinclair Cunningham
Life of this patent
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Abstract
The invention relates to a piston machine comprising a plurality of pistons and changeable piston displacement for varying the torque and speed. The pistons are connected via control bores and distributor passages in the distributor of the machine to a high pressure and low pressure connection. To reduce the displacement a switching valve is provided via which the inactive pistons are connected together via their distributor passages and also possibly subjected to an external very low servo pressure or tank pressure. This reduces the frictional losses, increases the efficiency and avoids flow losses of the valve.
Claims11
Piston machine having a plurality of pistons with changeable piston displacement comprising a distributor in which control bores leading to the pistons and distributor passages connected to the control bores are provided, via which the pistons can be connected to a high pressure or a low pressure connection, and a flow control valve for displacement changing, said flow control valve being actuated by servo pressure, actuation of said flow control valve being effective to vary the number of effective pistons, characterized in that the displacement is reduced by means of the flow control valve disconnecting a number of said distributor passages from the high pressure and low pressure connections and connecting said number of said distributor passages from the high pressure and low pressure connections and connecting said number of distributor passages to each other and to servo pressure.
Dependencies are inferred from the claim text.