Komatsu PC200-8M0, Shop Manual, Page: 121 / 1254

SEN06119-00
PC200, 200LC, 220, 220LC-8M0 10-401
9
401 Hydraulic system, Part 1
Hydraulic pump
Function
q The pump converts the engine rotation trans-
mitted to its shaft to oil pressure and delivers
pressurized oil corresponding to the load.
q It is possible to change the discharge amount
by changing the swash plate angle.
Structure
q Cylinder block (7) is supported to shaft (1) by
spline (14).
q Shaft (1) is supported by front and rear bear-
ings (15).
q Tip of piston (6) is shaped as a concave ball
and shoe (5) is caulked to it to form one unit.
q Piston (6) and shoe (5) constitute the spherical
bearing.
q Rocker cam (4) has flat surface (A), and shoe
(5) is always pressed against this surface while
sliding in a circular movement.
q Rocker cam (4) conducts high pressure oil to
the cylinder surface (B) with cradle (2), which
is secured to the case, and forms a static pres-
sure bearing when it slides.
q Piston (6) carries out relative movement in the
axial direction inside each cylinder chamber of
cylinder block (7).
q Cylinder block (7) seals the pressurized oil to
valve plate (8) and carries out relative rotation.
q This surface is designed so that the oil pres-
sure balance is maintained at a suitable level.
q The oil inside the respective cylinder chambers
of cylinder block (7) is suctioned and dis-
charged through valve plate (8).