STRUCTURE, FUNCTION, & MAINTENANCE STANDARD HYDRAULIC PUMP 12 Function The rotation and torque transmitted to the pump shaft are converted into hydraulic energy, and pressurized oil is discharged according to the load. It is possible to change the discharge amount by changing the swash plate angle. Structure Cylinder block (7) is supported to shaft (1) by a spline, and shaft (1) is supported by the front and rear bearings. The tip of piston (6) is a concave ball, and shoe (5) is caulked to it to form one unit. Piston (6) and shoe (5) form a spherical bearing. Rocker cam (4) has flat surface A , and shoe (5) is always pressed against this surface while sliding in a circular movement.
Rocker cam (4) brings high pressure oil at cylinder surface B with cradle (2), which is secured to the case, and forms a static pressure bearing when it slides. Piston (6) carries out relative movement in the axial direction inside each cylinder chamber of cylinder block (7). The cylinder block seals the pressure oil to valve plate (8) and carries out relative rotation. This surface is designed so that the oil pressure balance is maintained at a suitable level. The oil inside each cylinder cham- ber of cylinder block (7) is sucked in and discharged through valve plate (8). 10-32 PC210/240-7K