(3) Valve cover group The valve cover group consists of valve cover(F, 311), valve cover(R, 312), valve plate(313, 314), spline coupling(114), booster(130) and valve plate pin(885). The valve plate having two melon-shaped ports is fixed to the valve cover and feeds and collects oil to and from the cylinder cover. The oil changed over by the valve plate is connected to an external pipeline by way of the valve cover. Now, if the drive shaft is driven by a prime mover(electric motor, engine, etc), it rotates the cylinder block via a spline linkage at the same time.
If the swash plate is tilted as in Fig(previous page) the pistons arranged in the cylinder block make a reciprocating motion with respect to the cylinder block, while they revolve with the cylinder block. If you pay attention to a single piston, it performs a motion away from the valve plate(oil sucking process) within 180 degrees, and makes a motion towards the valve plate(or oil discharging process) in the rest of 180 degrees. When the swash plate has a tilting angle of zero, the piston makes no stroke and discharges no oil. 312 314 114 130 311 885 313 885 36072MP03 2-9