摘要 |
A variable displacement axial piston hydraulic unit includes a flat port plate disposed between a stationery head and a rotatable cylinder barrel. An arcuate actuator piston extends from the port plate and is slidably disposed within an arcuate pocket in the head to define an actuator chamber. Similarly, an arcuate biasing piston extends from the port plate and is slidably disposed within an arcuate pocket defining a biasing chamber which continuously communicates with a discharge passage in the head. By selectably rotating the port plate relative to the head, the amount of fluid pressure carryover through TDC and BDC can be varied, thereby changing the swivel torque acting on the swashplate so that the swivel torque can be utilized to actually control the position of the swashplate. The rotational position of the port plate is controlled by controllably introducing pressurized fluid into the actuating chamber.
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