Vibratory Pump (Swashplate at zero angle) (Typical Example).
(4) Drive Shaft. (5) Piston. (6) Port plate. (7) Swashplate. (8) Cylinder. (9) Housing.
When the engine is running, drive shaft (4) and cylinder (8) are
rotating. There are seven pistons (5) in the cylinder. Port plate
(6) and swashplate (7) are fastened to or held by housing (9)
and do not rotate. When the cylinder is rotating, each of the
pistons follows the angle of the swashplate. If the swashplate
angle is zero, the pistons do not move in and out of the
cylinder and there is no oil flow. Charge oil from the charge
filter maintains oil pressure in the pump to keep the vibratory
circuit full of oil and to lubricate the pump components.