AP2D36 Double Section Pump Variable Displacement Excavator Gear Pump

AP2D36 Double-Section Gear Pump Excavator Hydraulic Parts Excavator Gear Pump Parts  R971063612 50510862 

Regarded as the "heart" of an excavator, the hydraulic pump is a key component powering all machine actions.
Core Function
Engine‑driven rotation of the hydraulic pump converts mechanical energy into pressure energy stored in hydraulic oil. High‑pressure oil is conveyed to hydraulic cylinders and motors to perform boom lifting, arm movement, bucket operation, machine travel and upper‑part slewing. The excavator cannot move without a functional hydraulic pump.
The engine makes internal pump components rotate rapidly, inhaling hydraulic oil and compressing it. High‑pressure oil passes through pipelines to actuate cylinders and motors for boom, arm, bucket, travel and slew motions. Oil returns to the tank once controls are released, completing the oil circulation cycle.
Power Input: A coupling connects the excavator engine to the hydraulic pump’s main shaft and piston cylinder block, driving their high‑speed rotation.
Oil Suction (Low‑Pressure)
Pistons housed within the cylinder block rotate with it. The swash plate causes pistons to reciprocate. When pistons retract, pump internal volume increases, forming negative pressure to suck oil from the tank.
Oil Discharge (High‑Pressure)
Extended pistons decrease internal volume, compressing oil into high‑pressure fluid, which is sent to the distribution valve via the valve plate and outlet port.
Automatic Flow Control (Core Variable Displacement Feature)
During heavy‑load work like soil digging or heavy object lifting, the pump automatically increases displacement and flow for stronger power. It reduces displacement under light‑load or no‑load situations to improve fuel efficiency. Servo valves and regulators inside adjust swash plate angles to change piston strokes.

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