CBHYA Gear Pump | CBHYA-G36/F3.5-AT High Pressure Hydraulic Pump

The CBHYA Series (specifically the CBHYA-G36/F3.5-AT configuration) of high-pressure tandem external hydraulic gear pumps manufactured by Chengyuan Hydraulic are premium fluid power displacement units designed to cross-reference the rigorous physical space constraints and heavy output limitations of mobile and vocational industrial machinery. Utilizing a tandem-staged modular layout, this pump system combines an asymmetrical front high-flow gear section and a rear auxiliary low-flow section propelled by a single, high-tensile shared master drive shaft, enabling independent or parallel power delivery to dual distinct operational manifolds. For the specific serial nomenclature provided—CBHYA-G36/F3.5-AT—Chengyuan applies precise floating bushing axial clearance compensation and micro-inch gear tooth shaving combinations to secure 100% original-place interchangeable plug-and-play compatibility for all standard mounting flanges, keyed drive shafts, and port boundaries. Prior to warehousing, every single gear pump goes through a mandatory 100% simulated continuous full-load dynamic efficiency evaluation and hyper-pressure spike audit, guaranteeing optimal volumetric preservation even under severe structural vibration profiles.

Technical Specifications :

• Brand Compatibility Matrix: Standard Industrial CB / CBHY Replacement Configuration

• Core Product Series Designation: CBHYA Series (High-Pressure Asymmetric Double Gear Pump Platform)

• Exact Model Nomenclature: CBHYA-G36/F3.5-AT

• Front Stage (Primary Pump) Displacement: 36.0 $cm^3/rev$ (G36 high-volume delivery group)

• Rear Stage (Secondary Pump) Displacement: 3.5 $cm^3/rev$ (F3.5 pilot/auxiliary low-volume group)

• Front Stage Continuous Rated Pressure: 200 bar to 250 bar (20 – 25 MPa / Up to 3625 psi)

• Rear Stage Continuous Rated Pressure: 160 bar to 200 bar (16 – 20 MPa / Up to 2900 psi)

• Rated Operational Speed Window: 1500 rpm to 2500 rpm

• Minimum Acceptable Input Velocity: 600 rpm

• Intermittent Extreme Velocity Maximum: 3000 rpm

• Port Orientation & Shaft Rotation Indexing (AT): A = Combi-flanged or threaded fluid union profile options; T = Right-Hand Clockwise (CW) rotation looking directly at the face of the drive shaft

• Drive Output Shaft Profile: Precision-ground standard cylindrical straight keyed shaft (Involute splined profiles customizable)

• Casing Structural Metallurgy: High-tensile, high-density die-cast aluminum alloy shell integrated with heavy-duty steel or cast iron front face-plates

Key Technical Advantages:

• Heavy-Duty DU Bearings with Forced Internal Hydrostatic Lubrication: The CBHYA series eliminates traditional internal needle rollers, adopting premium imported self-lubricating DU composite bushings. These bearings utilize specialized internal fluid cross-drilling channels that capture high-pressure internal system oil for forced cooling and lubrication. At low speed startup or high load peaks, a micro-dynamic oil barrier forms on the shaft journal, preventing metal-on-metal dry contact and extending fatigue life.

• Axial Floating Bushing Automatic Clearance Compensation: The inner cartridge mechanism incorporates lateral dual floating wear plates back-loaded by strategic “DUO” or “3-shaped” high-elasticity sealing rings. By redirecting system backpressure behind the flexible side plates, the bushings are pressed against the gear faces with micron accuracy. This dynamic axial seating self-adjusts for structural wear over years of heavy operation, holding volumetric efficiency above 93%.

• Micro-Honed Involute Straight Spur Gears with Low Trapped-Volume Profiles: The drive and idler gear shafts are forged from premium high-alloy structural steel, heat-treated via carbonitriding and ground to standard profiles with a total envelope tolerance within $\pm 2$ microns. The optimized involute profile reduces the volume of oil trapped between meshing teeth, compressing fluid ripple and silencing high-frequency fluid humming.

• Monoblock Lightweight High-Tensile Anti-Breathing Casing Shell: The main gear housing is cast as a single block from premium grade, short-grain structural aluminum alloy finished with an anti-scaling shot-peening procedure. Its tight internal micro-grain composition provides superb burst resistance against cyclic 250 bar pressure shocks. This allows a major weight reduction that suits modern mobile machine chassis layouts.

Application Areas:

• Mobile Construction Vehicle Auxiliary Networks: Dual-stage work-circuit and pilot control pump for wheel loaders, compact excavators, or crane steering circuits.

• Environmental Sanitation Up-Fit Equipment: Multi-branch separate circuit actuation for refuse compactors, heavy hook-lifters, and mechanical street sweepers requiring simultaneous independent brush and lift cylinder actuation.

• Industrial Modular Power Pack Units: Hi-Lo rapid approach and pressing circuits for small automation hydraulic presses, stamping tooling, and metal-scrap baling scrap-shears.

Expert Maintenance Tips:

• Mandatorily Cross-Verify Input Shaft Rotation to Prevent Immediate Seal Blowout: The CBHYA-G36/F3.5-AT is a strictly right-hand Clockwise (CW) rotation unit as designated by the “T” suffix. You must manually verify the rotation direction of the prime mover or transmission PTO shaft before installing the unit! Because external gear pumps feature fully asymmetrical internal low-pressure suction (large port) and high-pressure discharge (small port) zones, operating the pump backward will force high-pressure fluid directly into the suction zone, blowing out the front shaft lip-seal within 1 second of engagement.

• Enforce Pre-Filling Fluid Saturation and Manual Shaft Jogging Prior to Cold Start: Because a freshly unpacked gear pump contains only a trace layer of rust-inhibiting shipping oil, you must pre-fill the internal pump chambers with clean, matching hydraulic fluid through the high-pressure outlet port after securing the line connections, then turn the shaft by hand at least 3 revolutions to purge air pockets. Launching the pump completely dry will score the floating aluminum bushing faces, leading to immediate efficiency loss.

• Insulate Suction Connections Against Micro-Air Ingression to Avoid Erasing Cavitation Wear: Gear pumps are highly sensitive to suction-line flow restrictions and air ingestion. Torque down all intake flange fasteners using a calibrated tool and verify that the suction line ID measures at least 38mm to minimize intake vacuum drop. If even a microscopic leak allows ambient air to bubble into the oil, the subsequent micro-implosions under 250 bar loading will pit the internal wear plates and gear faces, causing sudden pressure degradation and heavy acoustic chattering.