Excavator Pump Parts A10VSO71 Piston Shoe For Hydraulic Oil Pump Spare Parts

Excavator Pump Parts A10VSO71 Piston Shoe For  Hydraulic Oil Pump  Spare Parts

Force Transmission & Self-Adapting Angular Motion
The piston moves linearly back and forth inside the cylinder block, and the swash plate is a fixed inclined component. Utilizing spherical hinge structure, the piston shoe swings freely following swash plate angle and transfers piston axial thrust smoothly to the swash plate. Without piston shoes, point contact emerges between piston ball head and swash plate, resulting in instant failure and severe abrasion.

Realise Conversion from Point Contact to Surface Contact to Reduce Stress
The piston ball head features spherical geometry, and each piston shoe has a large flat underside.
Ball head ↔ Piston shoe: mobile spherical hinge
Piston shoe underside ↔ Swash plate: surface sliding contact
Substantially enlarged contact area lowers pressure per unit area to accommodate long-cycle work of high-pressure pumps.

Hydrostatic Oil Film Lubrication (Most Important)
A tiny orifice hole exists at the piston shoe centre. High-pressure oil flows through piston interior, ball head and orifice into the bottom cavity, building a 10～30 μm thin high-pressure oil film between piston shoe and swash plate.
Highlights:
✅ Convert dry metal friction into liquid lubricated friction
✅ Prevent scratch and seizure of piston shoe and swash plate under direct metal contact
✅ Remove accumulated friction heat
Extra oil flows into pump housing and becomes internal leakage return fluid.

Maintain Permanent Contact Under Set Plate Preload
The set plate applies preload on piston shoe backs to maintain consistent contact with the swash plate. One full rotation of cylinder block drives each piston through one oil intake and one oil discharge cycle, with piston shoes sliding cyclically across the swash plate surface.

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