Excavator Pump Parts AP2D36 Piston shoe 2.409-00140 Set of 10pcs Excavator Parts

Excavator Pump Parts AP2D36 Piston shoe 2.409-00140 Set of 10pcs Excavator Parts

Force Conduction and Self-Adaptive Angular Movement
The piston creates reciprocating linear motion inside the cylinder block, and the swash plate is an inclined fixed component. By means of spherical hinge connection, the piston shoe swings freely following swash plate angle variation and transfers piston axial thrust smoothly onto the swash plate. Without piston shoes, point contact will appear between piston ball head and swash plate and trigger instant crushing and severe abrasion.

Realise Point-to-Surface Contact Transition to Alleviate Contact Stress
The piston ball head is spherical, and each piston shoe is fitted with a broad flat bottom surface.
Ball head ↔ Piston shoe: movable spherical hinge structure
Piston shoe underside ↔ Swash plate: surface sliding contact
Significantly enlarged contact surface lowers unit pressure to meet continuous working requirements for high-pressure pumps.

Hydrostatic Oil Film Lubrication (Indispensable)
A miniature orifice hole is arranged centrally on the piston shoe. High-pressure oil flows through piston interior, ball head and orifice into bottom recess and forms a 10～30 μm thin high-pressure oil film between piston shoe and swash plate.
Functions:
✅ Convert dry metallic friction into fluid friction
✅ Prevent scratching and thermal burnout of piston shoe and swash plate under direct metal contact
✅ Remove heat generated during friction
Spilled oil flows into pump housing and works as internal leakage return oil.

Maintain Consistent Contact Under Retainer Plate Action
The set plate pushes against piston shoe rear sides to ensure permanent fitting on swash plate. After cylinder block rotates one full cycle, each piston completes one suction stroke and one discharge stroke, and piston shoes slide repeatedly along swash plate surface.

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