AP2D21 AP2D25 Hydraulic Pump Spare Parts Kit Excavator Piston Copper Construction Machinery Parts Manufacturing Plant
Price:
Negotiable
MOQ:
1 Pc
Delivery Time:
7-15days
Product Description
AP2D21 AP2D25 Hydraulic Pump Spare Parts Kit Excavator Piston Copper Construction Machinery Parts Manufacturing Plant
The main hydraulic pump is the core power unit that supports the entire hydraulic circuit of an excavator. Driven by the machine’s engine, it transforms mechanical power into high-pressure hydraulic power and delivers pressurized fluid to hydraulic motors, enabling all working movements of the excavator. Most construction excavators are outfitted with axial variable displacement piston pumps. Mid-to-large size construction machines use integrated twin main pumps and a rear pilot gear pump assembly. Two separate high-pressure oil delivery lines feed the main control valve to realize composite working motions, with a nominal working pressure of 28 to 35MPa. The tail-mounted low-pressure pilot pump runs at a pressure of 3 to 4MPa with low flow output, supplying pilot pressure oil for control levers and main valve spool actuation. Piston assemblies mounted on the cylinder block and pump shell rotate synchronously with the main shaft, finishing oil suction and pressure build-up. Adjusting the inclination angle of the swash plate changes piston stroke length, thus altering the pump’s displacement capacity. The external servo regulator actuates swash plate movement based on hydraulic feedback signals. A larger tilt angle increases fluid flow and operating speed, while a smaller angle minimizes fuel consumption and prevents engine stalling. The valve plate isolates low-pressure inlet and high-pressure outlet channels to complete hydraulic oil distribution work. Three practical control modes are configured for pump operation. Constant power control automatically decreases pump displacement as load rises, safeguarding the engine and improving overall power utilization efficiency. The LS load-sensing system provides on-demand fluid flow and maintains low displacement during idling to achieve fuel economy. The HP pressure limiting function reduces pump displacement at peak pressure to prevent hydraulic pipes and cylinders from breaking. Frequently occurring malfunctions include internal leakage caused by piston wear, valve plate damage or regulator clogging, resulting in slow machine operation and power shortage. When the regulator is stuck at maximum displacement, the engine will be overloaded, produce black smoke and stall under heavy working loads. Massive internal leakage converts pressure loss into heat, causing abnormal hydraulic oil overheating. Air suction into the hydraulic system, inadequate oil level, and defective bearings and pistons will trigger abnormal operational noise. For regular maintenance, replace hydraulic oil and filters on schedule to avoid wear on precision internal parts. Ensure tight sealing of suction pipelines to prevent air intake and machine vibration, and keep hydraulic oil at the prescribed level to guarantee stable pump operation.
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Machinery Test Report
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Provided |
Warranty
|
3 Months |
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Video outgoing-inspection
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Provided | Brand Name |
OEM
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Place of Origin
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China | Product Name |
Hydraulic Pump
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Model
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AP2D21 AP2D25 | MOQ |
1 Piece
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| Quality |
High-Quality
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Delivery time
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7-15 Days
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Standard or Nonstandard
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Standard
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Application
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Excavator Machinery
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Size
|
Standard Size
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Packing | Wooden Box |
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Company
Lanzhou Fudong Guangqi Trading Co., Ltd
Location
No. 7 West South Binhe Road, Xigu District, Lanzhou City, Gansu Province, China
Contact Person
Liang