Piston pump
HENGYUHANG Axial Piston Variable Pump HYH4VTG Series
Engineered specifically for heavy-duty concrete transit mixer drum drives, the HENGYUHANG HYH4VTG Series 33 swashplate axial piston variable pump delivers high-power closed-circuit hydrostatic performance, stepless displacement regulation, integrated boost pump and pressure make-up relief valves, and a continuous nominal operating pressure of 400 bar and maximum peak pressure of 450 bar (6,525 psi / 45 MPa).
| Applications
Designed specifically as the primary hydraulic power drive for concrete transit mixers, truck-mounted cement mixers, mobile volumetric concrete trucks, and severe-duty mobile drum-rotating machinery. Featuring standardized SAE J744 127-4 (SAE C 4-bolt) mounting flanges, ANSI B92.1a splined drive shafts with optional integrated coupling flanges, and dual direct-acting high-pressure cross-relief valves, it provides seamless 1:1 OEM drop-in interchangeability for Bosch Rexroth A4VTG Series 33 pump installations.
| Key Technical Specifications
Product Model: Hengyuhang Axial Piston Variable Pump HYH4VTG Series 33
Brand Replacement: Bosch Rexroth A4VTG Series 33 (Sizes 71, 90; closed circuit concrete mixer pump) OEM or as requested.
Displacement: 71 and 90 cm³/rev across 2 standardized frame sizes (HYH4VTG 71, HYH4VTG 90)
Rotation Direction: Clockwise (R), counter-clockwise (L) (viewed from drive shaft end)
Speed Range: Nominal rated speed 3,050 to 3,300 r/min (Maximum permissible intermittent speed up to 3,600 r/min; minimum speed 500 r/min)
Peak Pressure: Nominal continuous working pressure 400 bar (5,800 psi); Maximum peak pressure 450 bar (6,525 psi / 45 MPa)
- Description
- Tecspecs
- Brand & Reference
- Download HENGYUHANG HYH4VTG Axial Piston Variable Pump PDF
- Send an Inquiry
| Overview of HENGYUHANG HYH4VTG Series 33
The HENGYUHANG HYH4VTG Series 33 represents a heavy-duty, high-performance axial piston variable displacement pump engineered specifically for closed-circuit hydrostatic transmission systems driving mobile concrete transit mixer drums. Built in two core frame sizes — HYH4VTG 71 (71 cm³/rev) and HYH4VTG 90 (90 cm³/rev) — oil flow delivery is steplessly variable from zero to maximum, directly proportional to both the drive rotational speed and the swashplate deflection angle. As the swashplate tilts through its neutral center position, hydraulic flow direction reverses smoothly and progressively, allowing rapid and shock-free switching between concrete mixing (charging/agitating) and discharging modes without hydraulic line shock or structural stress on the vehicle chassis.
Engineered with severe operating duty cycles in mind, the pump incorporates an integral internal auxiliary boost (charge) pump (20.5 cm³ for size 71; 27.0 cm³ for size 90) that continuously replenishes closed-loop leakage oil and supplies pilot pressure to the servo control cylinder. High-pressure protection is provided by two direct-operated high-pressure relief valves that simultaneously serve as boost make-up check valves, instantaneously shunting pressure overshoots and preventing cavitation in the closed loop. Standardized with an SAE J744 127-4 (SAE C 4-bolt) mounting flange, ANSI B92.1a heavy-duty involute splined drive shafts (available with or without an integrated driveshaft coupling flange), SAE J518 1-inch 450-bar high-pressure flange ports, and versatile through-drive auxiliary pump interfaces (SAE A or SAE B), the HYH4VTG Series 33 guarantees complete 1:1 mechanical, hydraulic, and dimensional interchangeability for Bosch Rexroth A4VTG Series 33 mixer pumps.
| Dimension of HENGYUHANG HYH4VTG Series 33
| Interface Data Needed with the Drawing Across the 2 Models
| Model / Size (HYH4VTG) | Series | Mounting Flange (SAE J744) | Drive Shaft Options (ANSI B92.1a) | Working Ports A, B (SAE J518 High-Pressure, 450 bar) | Suction Port S (DIN 3852, 5 bar abs) | Case Drain Ports T1, T2 (DIN 3852, 3 bar abs) | Air Bleed Port R (DIN 3852, 3 bar abs) | Stroking & Control Ports X1, X2, X3, X4, PS | Pressure Gauge Ports MA, MB (450 bar) |
|---|---|---|---|---|---|---|---|---|---|
| HYH4VTG 71 | 33 | SAE J744 127-4 (SAE C, 4-bolt pilot Ø 127 mm) | 1. V8: 1-3/8 in 21T 16/32DP (bare splined shaft); 2. C8: 1-3/8 in 21T with drive coupling flange | SAE 1 in, 4-M12 × 1.75 depth 17 mm | DIN 3852 M42 × 2 depth 20 mm | T1 (top): M26 × 1.5 depth 16 mm; T2 (side): M26 × 1.5 depth 16 mm | DIN 3852 M12 × 1.5 depth 12 mm | X1, X2: M12 × 1.5 (40 bar); X3, X4: M12 × 1.5 (40 bar); PS: M14 × 1.5 (40 bar) | MA, MB: DIN 3852 M12 × 1.5 depth 12 mm |
| HYH4VTG 90 | 33 | SAE J744 127-4 (SAE C, 4-bolt pilot Ø 127 mm) | 1. V9: 1-1/2 in 23T 16/32DP (bare splined shaft); 2. C9: 1-1/2 in 23T with drive coupling flange | SAE 1 in, 4-M12 × 1.75 depth 17 mm | DIN 3852 M42 × 2 depth 20 mm | T1 (top): M26 × 1.5 depth 16 mm; T2 (side): M26 × 1.5 depth 16 mm | DIN 3852 M12 × 1.5 depth 12 mm | X1, X2: M12 × 1.5 (40 bar); X3, X4: M12 × 1.5 (40 bar); PS: M14 × 1.5 (40 bar) | MA, MB: DIN 3852 M12 × 1.5 depth 12 mm |
Note: Depending on the installation position, case drain port T1 or T2 must be connected to the oil reservoir below minimum fluid level. Both working ports A and B are located on the same side (left viewed from shaft end), with suction port S available in top position (02) or bottom position (01).
| Pump Installation Specifications
| Comprehensive Ordering Code Structure (Aligned with RS 92013 Series 33)
HYH4VT−G−Size−Control−Connector−Additional/33−M−Rotation−Seals−Flange−Shaft−PortPlate−Boost−ThroughDrive−Valves−Filter−Version
| Position | Code Element | Description & Selection Options |
|---|---|---|
| 01 | Axial Piston Unit | HYH4VT = Swashplate axial piston variable displacement pump, nominal pressure 400 bar, maximum peak pressure 450 bar, concrete mixer drum drives |
| 02 | Operating Mode | G = Closed circuit pump (Bomba, circuito cerrado) |
| 03 | Displacement Size (HYH4VTG) | 071 = 71 cm³/rev; 090 = 90 cm³/rev |
| 04 | Control Device | HW1 = Proportional hydraulic control, position-dependent, hex control shaft with control lever facing rearward (standard mechanical mixer linkage); EP3 = Proportional electric control, with manual emergency override and spring center return, supply voltage U = 12 V DC; EP4 = Proportional electric control, with manual emergency override and spring center return, supply voltage U = 24 V DC |
| 05 | Solenoid Connector | 0 = Without electrical connector (standard for HW1 mechanical control); P = Molded DEUTSCH 2-pin connector, without suppressor diode (for EP3 / EP4 electric controls) |
| 06 | Additional Functions | 0 = Without additional function; M = With mechanical stroke limiter, externally adjustable; T = With ports X3, X4 for stroking chamber pressure measurement/damping; B = With mechanical stroke limiter and ports X3, X4 |
| 07 | Series | 33 = Series 3, Index 3 |
| 08 | Threads Version | M = Metric connection and fastening threads |
| 09 | Direction of Rotation | R = Clockwise; L = Counter-clockwise (viewed from drive shaft end) |
| 10 | Sealing Material | N = NBR (nitrile rubber) body O-rings, high-performance FKM (fluorocarbon) shaft seal ring |
| 11 | Mounting Flange | C4 = SAE J744 127-4 (SAE C, 4-bolt metric mounting flange) |
| 12 | Drive Shaft | Size 071: V8 = ANSI B92.1a 1-3/8 in 21T 16/32DP splined shaft, without coupling flange; C8 = ANSI B92.1a 1-3/8 in 21T 16/32DP splined shaft, with pre-assembled drive coupling flange; Size 090: V9 = ANSI B92.1a 1-1/2 in 23T 16/32DP splined shaft, without coupling flange; C9 = ANSI B92.1a 1-1/2 in 23T 16/32DP splined shaft, with pre-assembled drive coupling flange |
| 13 | Port Plate / Port Location | 01 = Working ports A and B on bottom (same side left), suction port S located on bottom; 02 = Working ports A and B on bottom (same side left), suction port S located on top (standard configuration) |
| 14 | Charge / Boost Pump | F = Integrated auxiliary boost pump included |
| 15 | Through-Drive (Auxiliary Drive) | 0000 = Without through-drive (sealed rear cover); A2S2 = SAE J744 82-2 (SAE A 2-bolt), hub 5/8 in 9T 16/32DP (for auxiliary water pump or small gear pump); B2S4 = SAE J744 101-2 (SAE B 2-bolt), hub 7/8 in 13T 16/32DP |
| 16 | High-Pressure Relief Valves | A = Integrated direct-operated high-pressure cross-relief valves with built-in boost make-up function |
| 17 | Boost Filtration Circuit | S = Filtration in the suction line of the auxiliary boost pump |
| 18 | Standard / Special Execution | -0 = Standard single pump version; -K = Combined with mounted auxiliary pump; -S = Special execution customer variant; -T = Combined special execution variant |
| Reading Your Replacement Code
| Target Bosch Rexroth Part Code | HENGYUHANG HYH Equivalent | Interchange Verification Notes |
|---|---|---|
| A4VTG71HW100/33MRNC4V802F0000AS-0 | HYH4VTG-071-HW1-0-0/33-M-R-N-C4-V8-02-F-0000-A-S-0 | Direct 1:1 drop-in: HYH4VTG 71, HW1 mechanical servo control, clockwise, bare shaft V8 1-3/8 in 21T, suction port top 02 |
| A4VTG71HW100/33MRNC4C802F0000AS-0 | HYH4VTG-071-HW1-0-0/33-M-R-N-C4-C8-02-F-0000-A-S-0 | Direct 1:1 drop-in: HYH4VTG 71, HW1 mechanical servo control, clockwise, with coupling flange C8 for direct cardan shaft drive |
| A4VTG71EP4P0/33MRNC4V802F0000AS-0 | HYH4VTG-071-EP4-P-0/33-M-R-N-C4-V8-02-F-0000-A-S-0 | Direct 1:1 drop-in: HYH4VTG 71, EP4 24V DC proportional electric control, DEUTSCH 2-pin connector, bare shaft V8 |
| A4VTG90HW100/33MRNC4V902F0000AS-0 | HYH4VTG-090-HW1-0-0/33-M-R-N-C4-V9-02-F-0000-A-S-0 | Direct 1:1 drop-in: HYH4VTG 90, HW1 mechanical servo control, clockwise, bare shaft V9 1-1/2 in 23T, 90 cm³/rev mixer drive |
| A4VTG90HW100/33MRNC4C902F0000AS-0 | HYH4VTG-090-HW1-0-0/33-M-R-N-C4-C9-02-F-0000-A-S-0 | Direct 1:1 drop-in: HYH4VTG 90, HW1 mechanical servo control, clockwise, with coupling flange C9, standard concrete mixer build |
| A4VTG90EP4P0/33MRNC4C902FA2S2AS-0 | HYH4VTG-090-EP4-P-0/33-M-R-N-C4-C9-02-F-A2S2-A-S-0 | Direct 1:1 drop-in: HYH4VTG 90, EP4 24V electric control, coupling flange C9, SAE A through-drive A2S2 for auxiliary water pump |
Techspecs
4.1 Technical Data for HYH4VTG 71 and HYH4VTG 90 (Aligned with RS 92013)
| Parameter / Technical Specification | Symbol | Unit | HYH4VTG 71 | HYH4VTG 90 | Engineering Verification Notes |
|---|---|---|---|---|---|
| Displacement Size | — | — | 071 | 090 | Standard concrete mixer drum drive sizes |
| Geometric Displacement per rev | Vgₘₐₓ | cm³ | 71.0 | 90.0 | Main variable displacement rotary group |
| Integrated Boost Pump Displacement | Vgₛₚ | cm³ | 20.5 | 27.0 | Tested at boost pressure p=20 bar |
| Nominal Drive Speed (at Vgₘₐₓ) | nₙₒₘ | r/min | 3,300 | 3,050 | Maximum speed at continuous full displacement |
| Maximum Permissible Speed (at Vg<Vgₘₐₓ) | nₘₐₓ | r/min | 3,600 | 3,300 | Transient speed limit during diesel engine acceleration |
| Minimum Drive Speed | nₘᵢₙ | r/min | 500 | 500 | Ensures continuous lubrication of cradle bearings |
| Max. Flow Delivery (at nₙₒₘ, Vgₘₐₓ) | qᵥₘₐₓ | l/min | 234 | 275 | Maximum working flow to mixer drum drive motor |
| Drive Power at nₙₒₘ and Δp=400 bar | Pₘₐₓ | kW | 156 | 183 | Main pump shaft power (without boost pump consumption) |
| Drive Torque at Vgₘₐₓ and Δp=400 bar | Tₘₐₓ | N·m | 452 | 573 | Peak drive torque required during high-slump drum start |
| Drive Torque at Vgₘₐₓ and Δp=100 bar | T | N·m | 113 | 143 | Typical agitation torque under steady drum transit |
| Torsional Shaft Stiffness (V8 / V9 Shafts) | c | N·m/rad | 120,900 | 150,896 | High resistance against PTO torsional vibration |
| Rotary Group Moment of Inertia | J_TW | kg·m² | 0.0097 | 0.0149 | Low rotational inertia for dynamic drum reversing |
| Maximum Angular Acceleration | α | rad/s² | 21,000 | 18,000 | Valid between minimum and maximum drive speeds |
| Case Fluid Filling Volume | V | l | 1.3 | 1.2 | Minimum initial fluid filling volume required before startup |
| Pump Weight (without through-drive) | m | kg | 51 | 53 | Compact design minimizing vehicle payload impact |
4.2 Permissible Operating Pressure & Shaft Loading Limits (Aligned with RS 92013)
| Parameter | Permissible Limit | Engineering Operating Conditions |
|---|---|---|
| Nominal Working Pressure (pₙₒₘ) | 400 bar continuous | Absolute pressure at working port A or B |
| Maximum Peak Pressure (pₘₐₓ) | 450 bar peak | Single operating period t≤10 s; total cumulative period ≤300 h |
| Minimum Pressure (High-Pressure Side) | Minimum 25 bar | Ensures positive piston shoe hydrodynamic balance |
| Minimum Boost Pressure | Minimum 10 bar | System boost pressure setting must be higher depending on operating conditions |
| Rate of Pressure Change (RA) | Maximum 9,000 bar/s | Maximum allowable pressure gradient during dynamic mixer drum reversal |
| Boost Suction Pressure (Port S) | pₛₘᵢₙ≥0.8 bar abs (cold start ≥0.5 bar abs); pₛₘₐₓ≤5 bar abs | Continuous suction condition at boost inlet port S |
| Boost Pressure Valve Setting (pₛₚ) | Standard 22 bar at 1,500 r/min (pₛₚₙₒₘ=30 bar, pₛₚₘₐₓ=40 bar) | Factory set for stable pilot control and closed-loop make-up |
| Control Operating Pressure (pₛₜₘᵢₙ) | Minimum 22 bar at 1,500 r/min (measured at port PS) | Required pilot pressure for reliable HW and EP servo swiveling |
| Case Pressure (pₗ, Ports T1, T2, R) | Average continuous pₗ≤3 bar abs; maximum 6 bar abs | Short momentary peaks (t<0.1 s) up to 10 bar abs tolerated |
| Max. Permissible Input Torque (TEₘₐₓ) | 970 N·m (Size 71 V8 shaft); 1,305 N·m (Size 90 V9 shaft) | Drive shaft load capacity for pure torsional transmission |
| Max. Permissible Through-Drive Torque (TDₘₐₓ) | 250 N·m (both sizes 71 and 90) | Auxiliary drive capacity for water pump or secondary gear pump |
| Max. Radial Shaft Force (Fqₘₐₓ) | 5,600 N (Size 71); 7,100 N (Size 90) at a=24 mm | Overhung load capacity at shaft collar shoulder |
| Max. Axial Shaft Force (+Faxₘₐₓ/−Faxₘₐₓ) | +4,242 N/−2,758 N (Size 71); +4,330 N/−2,670 N (Size 90) | +Fax directed inward increases bearing life; −Fax must be minimized |
4.3 Hydraulic Fluid & Temperature Limits
| Parameter | Permissible Operating Limits | Optimal Recommended Target |
|---|---|---|
| Permissible Hydraulic Fluid | Mineral oil HLP according to DIN 51524 (Note: Not suitable for HFA, HFB, HFC fluids) | High-quality anti-wear mineral hydraulic fluid |
| Operating Viscosity (Continuous) | ν=10 to 400 mm²/s (cSt) | νₒₚₜ=16 to 36 mm²/s (cSt) |
| Cold Start Viscosity Limit | νₘₐₓ≤1,600 mm²/s (t≤3 min, p≤50 bar, n≤1,000 r/min) | Pre-warming period required in sub-zero ambient conditions |
| Short-Term Viscosity Limit | νₘᵢₙ=7 to 10 mm²/s (t≤3 min, p≤0.3×pₙₒₘ) | Measured at case drain port T1 |
| Operating Temperature Range | FKM shaft seal: −25 ∘C to +115 ∘C (Optional NBR shaft seal: −40 ∘C to +90 ∘C) | +30 ∘C to +65 ∘C (+86 ∘F to +149 ∘F) |
| Maximum Circuit Temperature | +115 ∘C (+239 ∘F) at working ports A and B | Protects fluid lubricity and rotary group film thickness |
| Required Fluid Cleanliness | ISO 4406 Class 20/18/15 (NAS 1638 Class 9) | Suction line filter element β₂₀≥100 recommended |
Advantages
Optimized High-Pressure Swashplate Architecture for Mixer Service
Designed for severe continuous duty in closed-circuit transit mixer drum drives, sustaining 400 bar continuous nominal pressure and 450 bar maximum peak pressure under heavy slump concrete loading.
Seamless Shock-Free Flow Reversal Through Neutral
Fluid delivery reverses progressively and symmetrically when passing through center zero, enabling smooth transition between charging (mixing) and discharging without damaging torque spikes on the truck chassis or reduction gearbox.
Integrated Auxiliary Boost Pump & Internal Make-Up Circuit
High-capacity internal trochoid boost pump (20.5 cm³ on size 71; 27.0 cm³ on size 90) provides continuous closed-loop fluid replenishment, rapid servo response, and positive anti-cavitation backpressure.
Dual High-Pressure Relief & Replenishment Valves
Direct-operated cross-over relief valves protect both forward and reverse high-pressure loop legs against abrupt drum jams, instantaneously bypassing excess pressure while preventing system cavitation.
Direct Mechanical Servo (HW1) and Electric (EP3/EP4) Controls
Standardized HW1 mechanical manual lever control allows direct mechanical connection to standard mixer control cables, while EP3/EP4 proportional electric controls support modern computerized in-cab and wireless remote drum speed control.
Universal Drop-In 1:1 Replacement for Rexroth A4VTG
Identical SAE C 4-bolt mounting flange, ANSI splined shaft with optional bolt-on companion drive flange, SAE 1" high-pressure ports, and auxiliary through-drive dimensions guarantee zero-modification field replacement.
Reference
6.1 Displacement & Control Configuration Matrix
Models Available: HYH4VTG 71, HYH4VTG 90 (displacements 71 and 90 cm³/rev).
Control Architectures Available:
HW1: Proportional hydraulic servo control with rearward-facing hex control lever for flexible mechanical cable linkage.
EP3 / EP4: Proportional electric servo control (12 V DC or 24 V DC) with spring center return, manual emergency override, and DEUTSCH 2-pin connector.
Mechanical Features:
Drive Shaft: ANSI B92.1a involute spline (1-3/8 in 21T for size 71; 1-1/2 in 23T for size 90), available bare (V8/V9) or equipped with pre-assembled cardan drive companion flange (C8/C9).
Through-Drive Options: Sealed rear cover (0000), SAE A auxiliary drive (A2S2, 5/8 in 9T), or SAE B auxiliary drive (B2S4, 7/8 in 13T) for powering truck-mounted water pressurization pumps or chute cylinders.
6.2 Target Brand Interchangeability Matrix
The HENGYUHANG HYH4VTG Series 33 provides verified 1:1 drop-in replacement across the complete Bosch Rexroth A4VTG Series 33 concrete transit mixer pump range:
Bosch Rexroth A4VTG71 Series 33 → HYH4VTG-071/33 (all HW1 mechanical, EP3 12V, EP4 24V, bare shaft V8, and flange shaft C8 configurations)
Bosch Rexroth A4VTG90 Series 33 → HYH4VTG-090/33 (all HW1 mechanical, EP3 12V, EP4 24V, bare shaft V9, and flange shaft C9 configurations)
Brand Replacement
The HENGYUHANG HYH4VTG Series 33 axial piston variable pump is manufactured specifically as an uncompromising, high-precision 1:1 OEM drop-in replacement for the Bosch Rexroth A4VTG Series 33 concrete mixer pump range. Manufactured under strict ISO 9001 certified production controls, every unit undergoes comprehensive dynamic test bench validation, measuring volumetric efficiency (>92%), mechanical efficiency, high-pressure relief valve crack pressure (400/420 bar), boost pressure stability (22 bar at 1,500 r/min), and swashplate response hysteresis.
Featuring identical SAE J744 127-4 (SAE C) 4-bolt mounting pilots (Ø127 mm), standardized shaft centerline height, identical companion coupling flange bolt circles, SAE J518 1-inch metric high-pressure port flange positions, and matching M42×2 suction ports, HYH4VTG pumps install directly into concrete mixer truck chassis without baseplate modification, cardan shaft shortening, or hydraulic hose rerouting. Commercial ready-mix concrete operators, mixer fleet maintenance facilities, and heavy construction equipment repair centers achieve immediate machine uptime, dramatic reduction in lead times, and substantial capital savings.
Applications
Truck-Mounted Concrete Transit Mixers: Primary hydrostatic closed-circuit drum drive pumps for 6 to 12 cubic meter concrete mixer trucks, providing continuous mixing during road transit and high-speed discharge at job sites.
Trailer-Mounted & Semi-Trailer Concrete Mixers: Heavy-duty variable displacement hydraulic power units for high-volume articulated concrete transport rigs.
Volumetric Mobile Concrete Mixers: Closed-circuit variable hydrostatic drives for continuous mobile on-site batching plants and volumetric mixer augers.
Industrial Concrete Drum Agitators: High-torque hydrostatic rotation systems for precast concrete plant holding drums and stationary transit hoppers.
Severe-Duty Mobile Material Mixing Machinery: Hydrostatic rotating drum drives for dry-bulk road stabilization spreaders, asphalt slurry mixers, and soil remediation units.
Auxiliary-Driven Mixer Support Systems: Power units equipped with SAE A/B rear through-drives simultaneously powering auxiliary wash-down water pumps and hydraulic chute fold/swing cylinders.
Package & Shipping
| Packaging Construction | Heavy-duty export fumigation-free wooden case with reinforced internal shock-absorbing positioning cradles |
| Corrosion Protection | Internal test fluid preservation, external high-grade anti-rust oil coating, and vapor corrosion inhibitor (VCI) heat-sealed barrier bag |
| Port & Shaft Protection | Heavy-duty threaded steel/plastic port sealing plugs and precision plastic drive shaft / coupling flange protective sleeves |
| Package Dimensions | Approx. 580 × 420 × 410 mm (HYH4VTG 71 / 90) |
| Gross Weight | Approx. 62 kg (HYH4VTG 71); Approx. 65 kg (HYH4VTG 90) |
| Standard Lead Time | 3 – 5 business days for standard stocked configurations; 15 – 25 business days for volume OEM production batches |
| Global Shipping Options | Express air courier (DHL / FedEx / UPS / TNT) for emergency breakdown replacements; Ocean FCL/LCL and Air cargo for volume commercial orders |
| Custom Documentation | Certificate of conformity, factory computerized dynamic test bench graphs, and OEM private-label nameplates supported |
Why Choose Hengyuhang?
Direct Factory Precision Manufacturing & CNC Excellence: Manufactured in our state-of-the-art production facility equipped with high-precision 4-axis and 5-axis CNC machining centers, automated gear hobbing, and CNC gear tooth profile grinding (Ra < 0.2 μm) to ensure superior surface finish, ultra-tight internal clearances, and maximum volumetric efficiency.
100% Full-Cycle Multi-Parameter Factory Inspection: Every single pump undergoes computerized testing before packaging, verifying flow rate at rated speed, volumetric efficiency (>91–93%), mechanical efficiency, continuous and peak pressure hold, internal bypass, and noise spectrum. Zero untested units leave the factory.
Seamless 1:1 OEM Drop-In Interchangeability: Dimensionally matched to European, SAE, and DIN standards, providing 1:1 direct mechanical interchangeability across premier global brands (Bosch Rexroth, Parker, Danfoss, etc.) with zero mounting modifications required.
Flexible Engineering Customization & Rapid Prototyping: Supported by a senior fluid power engineering team, offering custom displacement combinations, specialized shaft tapers, splines, integrated priority or relief valves, and non-standard port orientations with rapid sample prototyping and low MOQ requirements.
Robust Supply Chain, Extensive Inventory & Fast Global Dispatch: Extensive raw material stock of high-grade ductile cast iron castings, alloy steel gear sets, and bearing assemblies enables rapid assembly and 48–72 hour dispatch for emergency breakdown replacements, supported by complete export logistics.
12-Month Comprehensive Warranty & Lifetime Technical Support: All pumps are backed by a comprehensive 12-month manufacturer warranty against defects in materials and workmanship, supplemented by 24/7 engineering consultation, CAD drawing verification, and lifecycle technical assistance.
HENGYUHANG Axial Piston Variable Displacement Pump HYH4VTG Series 33 (Heavy-Duty Swashplate Pump for Concrete Transit Mixer Drum Drives, 71.00~90.00 cm³/rev) is a specialized, high-pressure bi-directional swashplate-design axial piston variable displacement pump engineered specifically for closed-circuit hydrostatic drum drives in concrete transit mixer trucks and mobile construction batching vehicles. Manufactured as a dedicated custom replacement benchmarked directly against the global construction machinery standard Bosch Rexroth A4VTG Series 33 (covering frame sizes A4VTG 071 and A4VTG 090), the HYH4VTG pump integrates a heavy-duty rotary group, an auxiliary gerotor boost pump (charge pump), dual direct-operated high-pressure relief valves with integrated boost makeup check valves, and specialized hydraulic-mechanical servo or electro-proportional displacement controls. Flow direction reverses smoothly and steplessly as the swashplate tilts through the neutral center position (from discharge to charge and drum mixing to unloading), with delivery volume directly proportional to drive engine speed and swashplate displacement angle. Engineered to operate under severe continuous mixing and sudden discharge shock loads, the pump operates at a continuous nominal working pressure (p_nom) of 400 bar (5,800 psi / 40 MPa) and a maximum peak pressure (p_max) of 450 bar (6,525 psi / 45 MPa), spanning 2 standardized displacements of 71.0 and 90.0 cm³/rev (4.33 and 5.49 in³/rev). Featuring a standard SAE J744 127-4 (SAE C 4-bolt) mounting flange, heavy-duty ANSI B92.1a splined shafts (1 3/8 in 21T or 1 1/2 in 23T), unified side-mounted SAE J518 Code 62 1 in high-pressure working ports (A and B on the same flank), an integrated boost pump suction line (M42 × 2), and optional rear through-drive (SAE B 2-bolt / 7/8 in 13T) for auxiliary water pump or chute positioning drives, the HYH4VTG Series 33 provides a custom drop-in replacement solution for transit mixer manufacturers and fleet overhaul operations.
| Applications
The HYH4VTG Series 33 closed-circuit axial piston variable pump is designed for high-torque hydrostatic drum rotations and mobile batching drives subject to frequent start-stop cycles and continuous mixing:
Concrete Transit Mixer Trucks (6m³ to 12m³ Mixing Drums): Powers closed-loop hydrostatic drum drives on commercial concrete mixer trucks, providing stepless drum speed regulation during transport (mixing) and rapid counter-rotation for clean concrete discharge at job sites.
Mobile Concrete Batching & Volumetric Mixers: Delivers reliable high-pressure hydraulic propulsion for continuous volumetric batching trucks, mobile mortar mixers, and volumetric concrete dispensers.
Underground Mining & Tunnel Shotcrete Transporters: Drives compact mixer drums on low-profile underground mine concrete transporters and tunnel shotcrete mixing rigs operating in confined spaces.
Precast Concrete Yard Transport Vehicles: Powers dedicated yard transit hoppers and heavy precast concrete casting wagons requiring smooth, creep-speed drum rotation and high braking torque.
Asphalt & Slurry Seal Mobile Applicators: Drives rotating agitation vats and emulsion mixing tanks on slurry seal trucks and asphalt micro-surfacing paving machines.
Industrial Blending & Agitation Transporters: Supplies closed-loop bi-directional fluid power for heavy industrial bulk blending drums and chemical powder transport agitation vessels.
| Key Specifications Overview
| Parameter | Benchmark Engineering Specification (Rexroth A4VTG Series 33 Target Standard) |
|---|---|
| Pump Architecture | Variable Swashplate Axial Piston Pump for Closed-Circuit Concrete Transit Mixer Hydrostatic Transmissions (Series 33) |
| Standard Displacement Frame Sizes | 2 Standard Commercial Frame Sizes: HYH4VTG 071 (71.0 cm³/rev) and HYH4VTG 090 (90.0 cm³/rev) |
| Continuous Nominal Pressure (p_nom) | 400 bar (5,800 psi / 40 MPa) continuous nominal pressure at working service ports A and B |
| Maximum Peak Operating Pressure (p_max) | 450 bar (6,525 psi / 45 MPa) peak operating pressure (single period max 10 s, cumulative 300 h) |
| Minimum Working Pressure (High-Pressure Side) | 25 bar (363 psi) minimum pressure required at active high-pressure port to ensure rotary group stability |
| Maximum Rate of Pressure Change (RA_max) | 9,000 bar/s (130,500 psi/s) maximum permissible rate of pressure build-up and reduction across the operating range |
| Integrated Auxiliary Boost Pump (Charge Pump) | Built-in gerotor boost pump: 20.5 cm³/rev (Size 071) and 27.0 cm³/rev (Size 090) at p = 20 bar for makeup and pilot feed |
| Nominal Boost Pressure Setting (p_Sp) | Nominal boost pressure: 22 bar (at n = 1500 rpm); continuous boost pressure limit p_Sp_nom = 30 bar; peak max p_Sp_max = 40 bar |
| Suction Port Pressure Limits (p_S abs) | Continuous minimum suction pressure p_S_min ≥ 0.8 bar absolute; cold-start limit ≥ 0.5 bar (t < 3 min); max p_S_max ≤ 5.0 bar absolute |
| Case Drain Pressure Limits (p_L max) | Continuous average case pressure ≤ 3.0 bar (43.5 psi) absolute; maximum permissible case peak ≤ 6.0 bar (87 psi); short peak < 10 bar (t < 0.1 s) |
| Nominal Drive Speed Range (n_nom @ Vg_max) | 3300 rpm (HYH4VTG 071) and 3050 rpm (HYH4VTG 090); minimum permissible operating speed n_min = 500 rpm |
| Delivery Flow Rating @ n_nom (qv_max) | 234 L/min (61.8 gpm) for Size 071 @ 3300 rpm; 275 L/min (72.6 gpm) for Size 090 @ 3050 rpm |
| Drive Power Consumption @ 400 bar (P_max) | 156 kW (209 hp) for Size 071 @ 3300 rpm; 183 kW (245 hp) for Size 090 @ 3050 rpm (excluding boost pump) |
| Drive Torque Output @ 400 bar (T_max) | 452 Nm (333 lb-ft) for Size 071; 573 Nm (423 lb-ft) for Size 090 (113 Nm and 143 Nm at Δp = 100 bar) |
| Maximum Permissible Shaft Input Torque (TE_max) | 970 Nm (Shaft V8: 1 3/8 in for Size 071); 1305 Nm (Shaft V9: 1 1/2 in for Size 090) for load-free transverse operation |
| Mounting Flange Standard (SAE J744) | SAE J744 127-4 (SAE C 4-bolt standard); Centering pilot Ø127.0 mm (-0.063 mm); 4-hole secure chassis mounting |
| Drive Shaft Configurations (ANSI B92.1a) | Involute splined shafts: 1 3/8 in 21T 16/32DP (Shaft V8 / Flange C8 for 071); 1 1/2 in 23T 16/32DP (Shaft V9 / Flange C9 for 090) |
| Working Ports Configuration (SAE J518 Code 62) | Ports A and B positioned on the same side: SAE J518 Code 62 1 in (M12 × 1.75, 20 mm deep, 450 bar rating) for simplified mixer piping |
| Auxiliary Boost Suction Port S | DIN 3852 M42 × 2 metric female thread (20 mm deep, 5 bar max) oriented downwards for direct gravity feed from reservoir |
| Dual High-Pressure Relief & Boost Valves | Direct-acting high-pressure relief valves with integrated charge makeup check valves (preset settings: 350, 380, 400, or 420 bar) |
| Modular Control Options | HW1 (Manual hydraulic servo with hexagonal shaft and rearward lever); EP3 (12V DC proportional); EP4 (24V DC proportional with override) |
| Through-Drive Auxiliary Option (Code B2S4) | SAE J744 101-2 (SAE B 2-bolt) with ANSI 7/8 in 13T 16/32DP internal splined hub; Max through-torque TD ≤ 250 Nm |
| Shaft Seal & Operating Temperature Range | NBR nitrile rubber housing seals with high-performance FKM fluoroelastomer shaft seal; Operating temperature: -25°C to +90°C (up to +115°C peak) |
| Fluid Cleanliness Standard | ISO 4406 Class 20/18/15 minimum (Class 19/17/14 recommended for extended swashplate bearing and valve plate life) |
| Technical Performance Matrix Across Available Sizes
| Model Code (Custom Replacement) | Displacement (cm³/rev) | Operating Pressure (bar / psi) | Rotational Speed (rpm) | Delivery Flow @ n_nom (L/min) | Drive Power @ 400 bar (kW) | Torque Output (Nm) | Case Fill (L) | Pump Mass (kg, approx) | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Main (Vg_max) | Boost (Vg_Sp) | Nominal (p_nom) | Peak (p_max) | Nominal (n_nom) | Min (n_min) | @ 400 bar | @ 100 bar | |||||
| HYH4VTG 071 | 71.0 | 20.5 | 400 / 5,800 | 450 / 6,525 | 3300 | 500 | 234.0 | 156.0 | 452 | 113 | 1.3 | 51.0 |
| HYH4VTG 090 | 90.0 | 27.0 | 400 / 5,800 | 450 / 6,525 | 3050 | 500 | 275.0 | 183.0 | 573 | 143 | 1.2 | 53.0 |
| Specialized Transit Mixer Control Devices and Operating Principles
| Control Code | Control Mechanism | Operating Parameters & Input | Functional Dynamics & Mixer Truck Benefit |
|---|---|---|---|
| HW1 | Hydraulic-Mechanical Servo Control (Position-Dependent with Rearward Lever) | Hexagonal shaft control with actuation lever facing rearward; Deflection angle: ±29° max; Operating force: approx. 15 ~ 30 N | Dedicated mechanical control for transit mixer trucks. Allows direct Bowden cable or mechanical linkage connection to the mixer cab and rear truck station. Internal hydraulic servo tracking ensures effortless, jerk-free lever movement regardless of high 400 bar working pressure. |
| EP3 / EP4 | Electrical Proportional Control (with Emergency Manual Override) | Control voltage: EP3 (12 V DC) / EP4 (24 V DC); Solenoids with 2-pin molded DEUTSCH DT04-2P connectors; Current: 400 ~ 1200 mA (12V) / 200 ~ 600 mA (24V) | Enables modern CAN-bus electronic vehicle control, electronic joysticks, or wireless remote control pendants for mixer drum operation. Includes emergency mechanical screw override and spring centering to neutral in case of electrical power loss. |
| Option M | Mechanical Stroke Limiter (External Adjustment) | External adjustable stroke limiter screws on the control housing | Enables precise mechanical calibration of maximum drum discharge or mixing speed to match customer-specific truck drum gearbox ratios and regional road regulations. |
| Option T / B | Stroking Chamber Pressure Test Ports (X3, X4) | Threaded diagnostic ports DIN 3852 M12 × 1.5; 12 mm deep (40 bar max) | Provides direct diagnostic access to the left and right servo cylinder chambers (X3 and X4) for rapid field pressure tuning and diagnostic troubleshooting during fleet maintenance. |
| Mounting Flange, Shaft and Port Specifications
| Model Size | Mounting Flange (SAE J744 Standard) | Drive Shaft (ANSI B92.1a Involute Splined) | High-Pressure & Auxiliary Ports (SAE J518 / DIN 3852) |
|---|---|---|---|
| HYH4VTG 071 | SAE J744 127-4 (SAE C 4-bolt standard); Centering pilot Ø127.0 mm (-0.063 mm); 4-hole robust chassis mounting | Splined V8: ANSI B92.1a 1 3/8 in 21T 16/32DP (TE_max = 970 Nm); Splined C8: with companion coupling flange | Ports A, B: SAE J518 Code 62 1 in (M12 × 1.75, 20 deep, 450 bar max, same side); Suction S: DIN 3852 M42 × 2 (20 deep, bottom); Drain T1/T2: DIN 3852 M26 × 1.5; Bleed R: M12 × 1.5; Gauge MA/MB: M12 × 1.5 |
| HYH4VTG 090 | SAE J744 127-4 (SAE C 4-bolt standard); Centering pilot Ø127.0 mm (-0.063 mm); 4-hole robust chassis mounting | Splined V9: ANSI B92.1a 1 1/2 in 23T 16/32DP (TE_max = 1305 Nm); Splined C9: with companion coupling flange | Ports A, B: SAE J518 Code 62 1 in (M12 × 1.75, 20 deep, 450 bar max, same side); Suction S: DIN 3852 M42 × 2 (20 deep, bottom); Drain T1/T2: DIN 3852 M26 × 1.5; Bleed R: M12 × 1.5; Gauge MA/MB: M12 × 1.5 |
| Direct Interchangeability and OEM Replacement Matrix (Rexroth A4VTG Series 33)
| Hengyuhang Series | OEM Target Model | OEM Reference Code | Custom Replacement & Field Compliance |
|---|---|---|---|
| HYH4VTG 071 | Bosch Rexroth A4VTG 71 Series 33 | A4VTG 071 HW100 / 33MRNC4F81000AS-0 | Direct drop-in replacement for standard 6m³ to 9m³ concrete transit mixer drum drives; identical SAE C 4-bolt mounting flange, 1 3/8 in 21T splined shaft, unified side-mounted 1 in Code 62 ports, M42 × 2 bottom suction, and HW1 mechanical servo lever. |
| HYH4VTG 090 | Bosch Rexroth A4VTG 90 Series 33 | A4VTG 090 HW100 / 33MRNC4F91000AS-0 | High-capacity custom replacement for heavy 10m³ to 12m³ concrete transit mixers; identical SAE C 4-bolt mounting flange, reinforced 1 1/2 in 23T splined shaft, 1 in Code 62 high-pressure ports, 275 L/min flow rating, and 573 Nm torque @ 400 bar. |
| HYH4VTG Electronic | Rexroth A4VTG EP3 / EP4 Version | A4VTG...EP3P / A4VTG...EP4P | Direct replacement for electronic joystick or wireless remote controlled mixer trucks; features 12V DC or 24V DC proportional solenoids with molded DEUTSCH 2-pin connectors and emergency override. |
| HYH4VTG Through-Drive | Rexroth A4VTG with Through-Drive | A4VTG...B2S4 | Custom replacement featuring rear SAE J744 101-2 (SAE B 2-bolt) through-drive and 7/8 in 13T splined hub for mounting auxiliary water pressurized wash pumps or chute hydraulic positioning gear pumps. |
| Technical Performance Matrix Across Available Sizes
| Model Code (Custom Replacement) | Displacement (cm³/rev) | Operating Pressure (bar / psi) | Rotational Speed (rpm) | Delivery Flow @ n_nom (L/min) | Drive Power @ 400 bar (kW) | Torque Output (Nm) | Case Fill (L) | Pump Mass (kg, approx) | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Main (Vg_max) | Boost (Vg_Sp) | Nominal (p_nom) | Peak (p_max) | Nominal (n_nom) | Min (n_min) | @ 400 bar | @ 100 bar | |||||
| HYH4VTG 071 | 71.0 | 20.5 | 400 / 5,800 | 450 / 6,525 | 3300 | 500 | 234.0 | 156.0 | 452 | 113 | 1.3 | 51.0 |
| HYH4VTG 090 | 90.0 | 27.0 | 400 / 5,800 | 450 / 6,525 | 3050 | 500 | 275.0 | 183.0 | 573 | 143 | 1.2 | 53.0 |
| Hengyuhang Series | OEM Target Model | OEM Reference Code | Custom Replacement & Field Compliance |
|---|---|---|---|
| HYH4VTG 071 | Bosch Rexroth A4VTG 71 Series 33 | A4VTG 071 HW100 / 33MRNC4F81000AS-0 | Direct drop-in replacement for standard 6m³ to 9m³ concrete transit mixer drum drives; identical SAE C 4-bolt mounting flange, 1 3/8 in 21T splined shaft, unified side-mounted 1 in Code 62 ports, M42 × 2 bottom suction, and HW1 mechanical servo lever. |
| HYH4VTG 090 | Bosch Rexroth A4VTG 90 Series 33 | A4VTG 090 HW100 / 33MRNC4F91000AS-0 | High-capacity custom replacement for heavy 10m³ to 12m³ concrete transit mixers; identical SAE C 4-bolt mounting flange, reinforced 1 1/2 in 23T splined shaft, 1 in Code 62 high-pressure ports, 275 L/min flow rating, and 573 Nm torque @ 400 bar. |
| HYH4VTG Electronic | Rexroth A4VTG EP3 / EP4 Version | A4VTG...EP3P / A4VTG...EP4P | Direct replacement for electronic joystick or wireless remote controlled mixer trucks; features 12V DC or 24V DC proportional solenoids with molded DEUTSCH 2-pin connectors and emergency override. |
| HYH4VTG Through-Drive | Rexroth A4VTG with Through-Drive | A4VTG...B2S4 | Custom replacement featuring rear SAE J744 101-2 (SAE B 2-bolt) through-drive and 7/8 in 13T splined hub for mounting auxiliary water pressurized wash pumps or chute hydraulic positioning gear pumps. |
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