A11VO Series Variable-Axis Axial Piston Hydraulic Pump: Technical White Paper

 

The Elephant Fluid Power A11VO series variable axial piston hydraulic pumps (including models A11VO60, A11VO75, A11VO95, A11VO130, A11VO145, A11VO190, A11VO220, A11VO260, and the high-speed A11VLO version) employ a swash plate variable design identical to that of Bosch Rexroth's A11VO/A11VLO series, featuring core technical advantages such as continuously variable displacement (with Vg max to Vg min = 0). These pumps operate at nominal pressures up to 350 bar (peak pressure: 400 bar) and are specifically designed for open-loop hydraulic systems, finding extensive applications in concrete pump trucks, earthmoving machinery, road construction equipment, compaction machines, lifting systems, mining machinery, drilling rigs, and other mobile machinery. This article systematically examines the core competitiveness of the Elephant Fluid Power A11VO series across six dimensions: technical principles, full specification parameters, control modes, application scenarios, compatibility with original Rexroth components, and supply chain benefits, providing authoritative technical guidance and procurement references for global hydraulic system integrators, construction equipment manufacturers, and end-users.

 

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Chapter 1: Technical Principles and Core Design Advantages of the A11VO Series

1.1 Structural Principle of the Diagonal Disc Variable-Axis Axial Piston

The A11VO series hydraulic pumps feature a classic swash plate axial piston design—a decades-proven industrial standard in open-loop variable hydraulic transmission systems, specifically optimized for mobile machinery applications. Compared to bent-axis designs, the swash plate configuration offers significant advantages in compactness, cost-effectiveness, and control flexibility.

Diaphragm tilt angle variable mechanism

The cylinder centerline coincides with the drive shaft centerline, and the piston contacts the swash plate via a sliding shoe. When the swash plate's swing angle is 0°, the piston exhibits no reciprocating motion and the output flow rate is zero; as the angle increases, the piston's reciprocating stroke expands, and the output flow rate becomes proportional to the swing angle. The variable displacement mechanism achieves stepless variation in displacement from Vg_max to Vg_min = 0 by adjusting the swash plate angle (from 0° to maximum), thereby precisely controlling both output flow rate and pressure. This design ensures nearly zero flow output during standby operation, significantly reducing energy consumption and heat generation.

Static Pressure Unloading Cradle Bearing

The design employs a cradle bearing with hydrostatic pressure relief, where the swash plate is supported by a hydrostatic oil film, resulting in minimal friction loss and rapid response. This configuration ensures optimal contact between the swash plate and the piston shoe under high-pressure and high-speed conditions, achieving a volumetric efficiency of over 95% and a mechanical efficiency exceeding 90%. Even at 350 bar pressure and 2500 rpm speed, stable performance output is maintained.

Double oil discharge port design

The standard configuration features two oil discharge ports (L1 and L2), allowing flexible selection of the oil discharge pipeline routing based on installation space to simplify system design. The oil discharge pipeline must be separately connected to the oil tank to ensure housing pressure does not exceed 0.5 bar, thereby protecting the shaft seal and sealing system. For high-temperature applications, the dual-discharge port design enhances heat dissipation efficiency.

1.2 Special Design Features and Self-Suction Capability for Open Circuits

The A11VO series is specifically designed for open-circuit hydraulic systems and features the following key characteristics:

• Flow rate is directly proportional to rotational speed and displacement: output flow rate qv = Vg × n × ηv / 1000 (L/min), where Vg represents current displacement (cm³/rev), n denotes rotational speed (rpm), and ηv indicates volumetric efficiency (typically 0.95–0.97).

• Pressure is determined by external load: the pump's output pressure depends on system demand, with automatic regulation of displacement and pressure via control modes (LR/DR/LRDS/DRS/HD/EP, etc.) to achieve energy-efficient operation.

• Excellent self-priming performance: The pump operates under self-priming conditions and functions normally whether the oil tank is pressurized or equipped with an integrated booster pump (centrifugal pump/impeller pump). The optimized oil suction port design and plunger return mechanism ensure outstanding self-priming capability under standard installation conditions (oil suction height ≤ 800 mm).

• High-speed A11VLO version: Available in sizes ranging from 130 to 260 mm, this model can be equipped with an impeller pump (A11VLO) for exceptionally high rotational speeds, meeting the demands of high-speed mobile machinery.

1.3 Advantages of Axial Drive and System Integration

100% shaft-driven capability

The A11VO series pumps feature through-shaft drive capability, supporting either gear pumps or axial piston pumps of equivalent specifications (100% through-shaft drive). This design offers: – The ability to connect a make-up pump, gear pump, or auxiliary piston pump in series after the main pump, simplifying hydraulic system layout; – Elimination of additional installation space and couplings, reducing system complexity; – Direct power delivery from the main pump's drive shaft to the auxiliary pump, enhancing overall transmission efficiency; – For closed-loop applications, the make-up pump can be installed directly behind the main pump, creating a compact static hydraulic drive unit.

1.4 Summary of Core Competitive Advantages

Technical characteristics	Performance index	Industry Significance
Displacement adjustment range	Vg max → Vg min = 0 (continuously adjustable)	Implement on-demand fuel supply to eliminate overflow losses and achieve 20%-30% energy savings.
Nominal/Peak Pressure	350 bar / 400 bar	Meets the demands of high-pressure construction machinery and industrial applications.
maximum speed	From 3900 rpm (A11VO60) to 1800 rpm (A11VO260)	covers the entire range of operating conditions, from high-speed, low-flow to low-speed, high-flow scenarios.
volumetric efficiency	≥95%	Reduce energy consumption, minimize heat generation, and extend the service life of lubricating oil.
Mechanical Efficiency	≥90%	High power density, compact design
control method	More than 10 types, including LR/DR/LRDS/DRS/HD/EP/DH/LG, etc.	Adapt to various requirements for pressure, flow rate, power, and electro-hydraulic control
Central shaft drive	100% shaft-driven capability (same specifications)	Can be connected in series with a gear pump or an axial piston pump to simplify the system.
suction capacity	Excellent self-priming capability, with optional built-in booster pump available	Adapts to various installation conditions without requiring an additional oil replenishment pump

 

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Chapter 2: Detailed Explanation of Full Specification Technical Parameters for the Elephant Fluid Dynamics A11VO Series

2.1 Product Models and Displacement Matrix

The A11VO series comprises two structural sub-series: -A11VO Standard Version (60–260 specifications): features standard rotational speeds, suitable for general engineering machinery and industrial applications; -A11VLO High-Speed Version (60–260 specifications): an optimized high-speed variant that can be equipped with a built-in impeller pump (centrifugal pump) to achieve exceptionally high speeds, ideal for high-speed mobile machinery.

The technical specifications for the standard model of the Elephant Fluid Dynamics A11VO series are as follows:

Model	MaximumdisplacementVgmax (cm³/rev)	MinimumdisplacementVgmin (cm³/rev)	NominalPressure (bar)	PeakPressure (bar)	MaximumSpeed@Vgmax (rpm)	Maximumspeed@Vg≈0(rpm)	Maximumoutputflow@n_max (L/min)	MaximumPower@350bar(kW)	Weight (kg)
A11VO60	60.0	0	350	400	3300	3900	198.0	115.5	28
A11VO75	75.0	0	350	400	3000	3600	225.0	131.3	32
A11VO95	95.0	0	350	400	2700	3100	256.5	149.6	38
A11VO130	130.0	0	350	400	2500	2900	325.0	189.6	48
A11VO145	145.0	0	350	400	2400	2800	348.0	203.0	52
A11VO190	190.0	0	350	400	2200	2600	418.0	243.8	68
A11VO220	220.0	0	350	400	2000	2400	440.0	256.7	78
A11VO260	260.0	0	350	400	1800	2100	468.0	273.0	95

Note: The above data are theoretical values based on operating conditions of drive speed n = 1500 rpm, oil viscosity v = 36 mm²/s, and oil temperature t = 50 °C. Actual values should account for efficiency losses and manufacturing tolerances.

2.2 Technical Specifications of the A11VLO High-Speed Version

The A11VLO series enhances high-speed performance over the A11VO model and can be equipped with an integrated impeller pump (centrifugal pump) to achieve exceptionally high rotational speeds.

Model	Maximum displacement Vg max (cm³/rev)	Nominal Pressure (bar)	Peak Pressure (bar)	Maximum Speed @Vg max (rpm)	Maximum speed @ Vg ≈ 0 (rpm)	Optionally equipped with an impeller pump	Typical Application
A11VLO60	60.0	350	400	3900	4500	deny	High-speed loader
A11VLO75	75.0	350	400	3600	4200	deny	High-speed forklift
A11VLO95	95.0	350	400	3100	3600	deny	High-speed excavator
A11VLO130	130.0	350	400	2900	3400	yes	concrete pump truck
A11VLO145	145.0	350	400	2800	3300	yes	Large crane
A11VLO190	190.0	350	400	2600	3100	yes	Large mining trucks
A11VLO220	220.0	350	400	2400	2900	yes	Large drilling equipment
A11VLO260	260.0	350	400	2100	2600	yes	Ultra-heavy-duty construction machinery

2.3 Key Performance Calculation Formulas

Pump discharge rate (proportional to displacement and driving speed): qv = Vg × n × ηv / 1000 (L/min)

Where: Vg is the current displacement (cm³/rev), n is the driving speed (rpm), and ηv is the volumetric efficiency (typically 0.95–0.97).

Pump output torque (proportional to displacement and pressure difference): T = Vg × Δp / (20π × η_mh) (Nm)

Where: Δp is the pressure difference (bar), and η_mh is the mechanical-hydraulic efficiency (typically 0.90–0.93).

Pump input power: P = qv × Δp / (600 × η_t) (kW)

Where: η_t represents total efficiency (typically ranging from 0.85 to 0.90).

The core principle of variable control is as follows: when high flow demand occurs (e.g., rapid extension of a hydraulic cylinder), the displacement Vg increases automatically; when pressure maintenance is required (e.g., hydraulic clamping), Vg decreases automatically to near zero. This on-demand oil supply mechanism ensures the system operates consistently in its highest efficiency zone, reducing overall energy consumption by 20–30% compared to a fixed-displacement pump plus relief valve configuration.

 

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Chapter 3: In-depth Analysis of Ten Control Methods

The core competitiveness of the A11VO series lies in its extensive range of control options. Elephant Fluid Power fully replicates all control features available in the Rexroth A11VO/A11VLO series.

3.1 LR – Power Control (Direct Control)

How it works: Equipped with a built-in power control valve that limits the pump's output power within a preset range. When system pressure rises, it automatically reduces displacement to maintain constant power; when pressure drops, it increases displacement to boost flow rate. Power control settings can be adjusted externally even during operation.

Technical Parameters: – Power range: Set according to the motor/engine's rated power – Control behavior: Prioritizes flow demand within the power limit; automatically reduces pressure or flow when reaching the limit – External adjustment: The power setting can be adjusted via external devices even during pump operation

Typical application: Engine-driven mobile machinery designed to prevent engine overload-induced shutdown, such as excavators, loaders, and bulldozers.

3.2 DR – Constant Pressure Control (Direct Control)

Working principle: Equipped with a built-in pressure control valve that limits the pump's maximum output pressure within a preset range. When system pressure reaches the set value, the pump automatically reduces its displacement to deliver only the flow required to maintain the pressure, eliminating overflow losses.

Technical Parameters: – Pressure setting range: Standard adjustable, covering the entire operating pressure range – Hysteresis and pressure rise: Δp_max ≈ 4 bar – Control deviation decreases as the set pressure value decreases

Typical applications: Systems requiring constant pressure, such as hydraulic clamping devices, hydraulic test benches, press pressure maintenance systems, and concrete pump truck pressure control systems.

3.3 LRDS – Power Control + Pressure Cut-off + Load-Sensitive Control

Working Principle: Integrates three functions—power control, pressure cutoff, and load sensitivity. The pump simultaneously maintains the set power, limits maximum pressure, and responds to load-sensitive signals, achieving comprehensive control of "constant power – pressure limitation – load sensitivity".

Technical Parameters: -Power Control: Same as LR characteristics, externally adjustable-Pressure Cut-off: Automatically cuts flow output when system pressure reaches the set upper limit-Load Sensitivity: Responds to LS signals, delivering only the required flow rate to eliminate throttling losses-Control Range: Multiple selectable levels for varying power and pressure requirements

Typical application: Main pumps for high-end construction machinery, such as large excavators, concrete pump trucks, and mining dump trucks, delivering optimal energy efficiency and engine protection.

3.4 DRS – Pressure Control + Load-Sensitive Control

Working principle: Integrates dual functions of pressure control and load-sensitive control. The pump simultaneously maintains the set pressure and responds to load-sensitive signals, achieving "constant-pressure-load-sensitive" control.

Technical Parameters: – Pressure Control: Same as DR characteristics – Load Sensitivity: Responds to LS signals and delivers only the required flow rate – Fast response time, ideal for hydraulic systems requiring rapid response

Common applications: Systems requiring simultaneous pressure control and response to load variations, such as cranes, aerial work platforms, and forestry machinery.

3.5 HD – Hydraulic Control (related to pilot pressure)

Working principle: The pump displacement is proportionally regulated by an external pilot pressure signal. Increased pilot pressure leads to increased displacement and consequently higher output flow rate. This hydraulic proportional control system features rapid response and high precision.

Technical parameters: -Control pressure differential: 10 bar or 25 bar (selectable) -Control starting point: Vg min (minimum displacement) corresponding to 0 bar pilot pressure-Control ending point: Vg max (maximum displacement) corresponding to 10/25 bar pilot pressure-Response time: <0.3 seconds

Common applications: Systems requiring hydraulic pilot control, such as excavator pilot control, loader pilot control, and crane pilot control.

3.6 EP – Electric Proportional Control (Proportional Electromagnet)

Working principle: The device receives current signals (12 V DC or 24 V DC) via an electroproportional electromagnet, converting the electrical signal into mechanical displacement to regulate pump displacement. It can be directly interfaced with PLCs or industrial control computers for digital control.

Technical Parameters: -EP1: 12 V DC, adjustable control current range -EP2: 24 V DC, adjustable control current range -Response time: <0.2 seconds -Control accuracy: ±1% displacement

Common applications: automated construction machinery, remotely controlled devices, electro-hydraulic integrated systems, and CNC hydraulic equipment.

3.7 DH – Hydraulic Control (related to pilot pressure; special version)

How it works: Similar to HD, but a specialized hydraulic control version designed for specific hydraulic system requirements. Control features can be customized according to customer needs.

Common applications: specialized hydraulic systems, such as marine hydraulic systems, aviation ground equipment, and military hydraulic systems.

3.8 LG – Lever Control (Mechanical Control)

Working principle: The pump displacement is directly adjusted via a mechanical lever. It is simple and reliable, requiring no external control of oil or power sources, and operates solely through mechanical control.

Typical applications: Simple mechanical control scenarios, such as small agricultural machinery, basic construction equipment, and manual hydraulic devices.

3.9 DH.D/DH.G – Hydraulic Control (Special Version)

Working Principle: DH.D and DH.G are specialized hydraulic control versions with unique operational characteristics, designed for specific applications. DH.D represents the dynamic control version, while DH.G denotes the gain control version.

Common applications: Systems requiring specialized dynamic response, such as high-speed injection molding machines, high-speed die-casting machines, and vibration-sensitive equipment.

3.10 EP.D / EP.G – Electric Proportional Control (Special Version)

Working principle: EP.D and EP.G are specialized versions of electric proportional control with distinct characteristics. EP.D employs dynamic electric proportional control, while EP.G uses gain-based electric proportional control.

Common applications: High-precision electro-hydraulic control systems, such as servo hydraulic systems, CNC machining centers, and precision testing equipment.

3.11 Control Method Selection Decision Matrix

 

Control method	Code	Control signal	Control range	Response speed	Applicable Model	Typical Application
power control	LR	Built-in mechanical valve	power limitation	Middle	60-260	Excavators, loaders, bulldozers
Constant Pressure Control	DR	Built-in mechanical valve	pressure limitation	Middle	60-260	Clamping device, test bench, concrete pump truck
Power + Pressure + Load Sensitivity	LRDS	Built-in mechanical valve + LS	Power + Pressure + Flow Rate	Middle	60-260	Large excavators, concrete pump trucks, mining trucks
Pressure and Load Sensitivity	DRS	Built-in mechanical valve + LS	Pressure + Flow Rate	Middle	60-260	Crane; High-altitude work platform
Hydraulic Ratio	HD	Hydraulic Leader	Vg min-Vg max	fast	60-260	Pilot control systems for excavators and loaders
Electrical Ratio	EP	12V/24V DC	Vg min-Vg max	fast	60-260	Automated equipment, remote control devices, CNC equipment
Special Hydraulic Control	DH	Hydraulic Pilot (Special)	custom made	fast	60-260	Ship hydraulic systems, aviation ground equipment, military equipment
Mechanical Lever	LG	Mechanical Lever	Vg min-Vg max	slow	60-260	Small agricultural machinery; simple construction equipment
Dynamic Hydraulic Control	DH.D	Hydraulic Pilot (Dynamic)	custom made	Extremely fast	60-260	High-speed injection molding machines, high-speed die-casting machines
Gain Electric Proportion	EP.G	Electrical Ratio (Gain)	custom made	Extremely fast	60-260	Servo hydraulic systems, CNC machining centers

 

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Chapter 4: In-depth Comparison of Compatibility with the Bosch Rexroth A11VO Series

4.1 Dimensions and Installation: 100% Interchangeability

The Elephant Fluid Dynamics A11VO series strictly adheres to Rexroth's original design specifications, ensuring complete physical interchangeability.

• Installation flange: Compliant with ISO 3019-2 standards, available in 2-hole and 4-hole configurations, with installation dimensional tolerance controlled within ±0.1 mm.

• Drive shaft end: Available in three options – DIN 6885 flat key shaft, DIN 5480 splined shaft, and ANSI B92.1a splined shaft – fully compatible with Rexroth's corresponding models.

• Oil port connection: SAE flanged oil port compliant with ISO 6162 standard, available in both metric and UNC thread options

• Control interfaces: LR/DR/LRDS/DRS/HD/EP/DH/LG – The control of oil port positions is fully compatible with Rexroth's original specifications.

• Oil discharge ports: Standard configuration includes two oil discharge ports (L1 and L2), positioned identically to those of the original Rexroth components.

• Axial drive: 100% axial drive capability (same specifications), compatible with series connection of gear pumps or axial piston pumps; flange and hub dimensions match those of original Rexroth components.

• Oil replenishment pump interface: The A11VLO series (specifications 130–260) can be equipped with a built-in impeller pump (centrifugal pump); the interface dimensions match those of the original Rexroth components.

4.2 Performance Parameters: Third-party Benchmark Testing

Through comparative testing conducted by the internationally renowned hydraulic testing institution (TUV Rheinland certification laboratory), the performance comparison between the Elephant Fluid Power A11VO series and Rexroth's original products is as follows:

Performance index	Elephant Fluid Dynamics A11VO130	Rexroth A11VO130	Contrast difference	Testing standard
volumetric efficiency	95.5%	96.0%	<0.6%	ISO 4409
Mechanical Efficiency	91.2%	91.5%	<0.4%	ISO 4409
gross efficiency	87.1%	87.6%	<0.6%	ISO 4409
Noise Level (dB(A))	75-77	74-76	match	ISO 4412-1
Pressure control accuracy	±3 bar	±2 bar	match	built in test
Power control accuracy	±2%	±1.5%	match	built in test
Variable Response Time	0.25s	0.22s	+0.03s	built in test
Continuous operating life	>15,000h	>15,000h	match	accelerated life test
price level	baseline	2.5 to 3.5 times that of an elephant	Significant advantage	market research

Note: Test conditions include a mineral oil medium, ISO VG46 standard, oil temperature of 40°C, nominal pressure of 350 bar, and operating speed of 1500 rpm.

4.3 Complete Reproduction of Control Methods

The Elephant Fluid Dynamics A11VO series fully supports all control modes of the Rexroth A11VO/A11VLO series.

• LR: Power control, externally adjustable

• DR: Constant Pressure Control, Direct Operation

• LRDS: Power control + Pressure cut-off + Load-sensitive control

• DRS: Pressure control + load-sensitive control

• HD: Hydraulic proportional control, dependent on pilot pressure

• EP: Electric proportional control, 12V/24V DC

• DH: Hydraulic Control, Special Version

• LG: Lever control, mechanical control

• DH.D/H/G: Hydraulic control, Dynamic/Gain version

• EP.D/EP.G: Electric proportional control, dynamic/gain version

The response characteristics, control curves, and electromagnet parameters of all control modes are identical to those of Rexroth's original components, enabling direct replacement without requiring reconfiguration of the control system.

4.4 Quality Certification System

• ISO 9001:2015 Quality Management System Certification

• CE certification complies with the EU Machinery Directive 2006/42/EC.

• RoHS certification: Compliance with the Directive on Restrictions of Hazardous Substances

• ATEX certification optional (II 2G Ex h IIC T4-T1 Gb X / II 3G Ex h IIC T4-T1 Gc X)

• China Classification Society (CCS) certification applies to ships and marine engineering applications

• TUV Rheinland Performance Testing Certification (optional)

 

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Chapter 5: Industry Application Scenarios and Solutions

5.1 Hydraulic System of Concrete Pump Trucks

Main Pump for Concrete Pumping Vehicles (A11VO130/A11VO145/A11VO190)

Concrete pump trucks typically employ A11VO130, A11VO145, or A11VO190 as the main pump. Through LRDS power control combined with pressure cutoff and load-sensing regulation, the system achieves the following functions: -Pumping phase: High-flow rapid pumping (Vg max); LRDS controls maximum power to prevent engine overload; -Pressure maintenance phase: High-pressure, low-flow pressure stabilization (reduced Vg while maintaining pressure); DR pressure cutoff ensures pumping pressure does not exceed safety limits; -Switching phase: Rapid response switching; load-sensing control provides only the required flow rate to eliminate throttling losses; -Energy-saving standby mode: Automatic reduction of displacement to near zero during pumping intervals, minimizing energy consumption and heat generation; -External power adjustment: Power settings can be modified via external devices even during operation to accommodate different concrete grades and delivery distances.

Compared to the conventional pump-and-overflow valve configuration, the A11VO variable pump reduces energy consumption by 25%–35%, lowers oil temperature rise, extends seal lifespan, and enhances the continuous operating capability of pump trucks.

5.2 Excavator Hydraulic System

Excavator main pump (A11VO60/A11VO75/A11VO95)

20–40-ton excavators typically employ a dual-pump system (one left and one right pump, either A11VO75 or A11VO95). Through LR power control or LRDS integrated control, the system achieves: – Compound operation: Independent control of both pumps enables coordinated movement of the boom, dipper mast, and rotation; LR control limits individual pump power to prevent engine stall. – Excavation force control: When excavation resistance increases, LR control automatically reduces displacement while maintaining constant power output for stable engine operation. – Travel drive: Combined with an A6VM variable motor, it utilizes closed-loop static hydraulic transmission for high efficiency and energy savings. – External power adjustment: Operators can modify power settings via external controls to switch between "Economic Mode" and "Power Mode" based on working conditions.

Main pumps for large excavators (A11VO130/A11VO145/A11VO190)

Large excavators in the 40–100-ton class typically employ A11VO130, A11VO145, or A11VO190 as their main pumps. The LRDS integrated control system delivers: – Ultra-high digging power: 350 bar high-pressure output for exceptional excavation capability; – Precise power control: LRDS dynamically matches engine power curves to achieve optimal fuel efficiency; – Load-sensitive response: rapid adaptation to load changes for precise operation.

5.3 Excavator and Loader Hydraulic Systems

Loader Hydraulic System (A11VO60/A11VO75/A11VO95)

-wheel loaders typically employ single-pump or dual-pump systems (A11VO75 or A11VO95). Through LR power control or DRS pressure-load sensitive control, the following functions are achieved: -Excavating operations: high-flow rapid loading (Vg max); LR control limits power to prevent engine overload; -Lifting operations: high-pressure lifting (reduced Vg with maintained pressure); DRS control ensures stable lifting force; -Travel drive: combined with an A6VM variable motor, it enables closed-loop static hydraulic transmission for high efficiency and energy savings; -Steering system: a through-shaft-driven series gear pump provides independent hydraulic power to the steering system.

Shovel excavator hydraulic system (A11VO95/A11VO130)

Excavators typically employ the A11VO95 or A11VO130 as their main pump. Through LRDS integrated control, they achieve: – Excavation, loading, transportation, and unloading: multi-functional pump operation with LRDS control adapting to varying power and flow requirements under different conditions; – Continuous operation: high-reliability design designed for sustained performance in harsh environments such as mines and construction sites.

5.4 Hydraulic Systems for Road Surface Machinery and Compaction Machinery

Roller Hydraulic System (A11VO60/A11VO75)

Vibration rollers typically employ A11VO60 or A11VO75 as the main pump. Through DR constant-pressure control or LR power control, the system achieves: – Travel drive: Constant-pressure control maintains a steady travel speed to ensure uniform compaction; – Vibration system: LR power control limits vibration intensity to prevent engine overload; – Steering system: A shaft-driven gear pump provides independent hydraulic power for the steering mechanism.

Paver Hydraulic System (A11VO75/A11VO95)

Asphalt pavers typically employ the A11VO75 or A11VO95 as their main pump. Through DRS pressure and load-sensing control, they achieve: – Paving speed control: Load-sensing control precisely matches paving speed requirements to ensure quality; – Tamping plate control: Constant-pressure regulation maintains uniform pressure on the tamping plate for smooth paving surface; – Material delivery system: High-flow delivery (Vg max) enhances operational efficiency.

5.5 Hydraulic Systems for Lifting Machinery

Automobile Crane Hydraulic System (A11VO95/A11VO130/A11VO145)

Automotive cranes typically employ A11VO95, A11VO130, or A11VO145 as the main pump. Through DRS pressure-load sensitive control or LR power control, the system achieves: -Lifting operations: load-sensitive control precisely matches lifting speed requirements for safe and smooth performance; -Telescoping operations: constant-pressure control maintains stable pressure during telescoping to ensure smooth movement; -Rotating operations: power control limits rotational torque to prevent engine overload; -Leg control: a through-shaft-driven series gear pump provides independent hydraulic power to the leg system.

Crawler Crane Hydraulic System (A11VO130/A11VO145/A11VO190)

Large crawler cranes typically employ A11VO130, A11VO145, or A11VO190 as the main pump. Through LRDS integrated control, the system achieves: – Ultra-high lifting capacity: 350 bar high-pressure output for exceptional lifting force; – Precise power control: LRDS dynamically matches engine power curves to optimize fuel efficiency; – Multi-mechanism coordination: load-sensing control enables synchronized operation of lifting, luffing, and slewing functions.

5.6 Hydraulic Systems for Mining Machinery and Drilling Equipment

Hydraulic System for Mine Self-Dumping Trucks (A11VO130/A11VO145/A11VO190)

Large mining dump trucks typically employ A11VO130, A11VO145, or A11VO190 as the main pump. Through LRDS integrated control, the system achieves: -Lifting and unloading: high-flow rapid lifting (Vg max), with LRDS controlling power limits and maximum pressure to ensure safety; -Steering system: independent hydraulic power supplied via a through-shaft-driven series gear pump; -Braking system: independent hydraulic power provided by a through-shaft-driven series gear pump; -Continuous operation: a highly reliable design tailored for demanding continuous performance in harsh mining conditions.

Hydraulic Systems for Drilling Equipment (A11VO145/A11VO190/A11VO220/A11VO260)

Large drilling equipment typically employs A11VO145, A11VO190, A11VO220, or A11VO260 as the main pumps. Through DR constant-pressure control or LR power control, the system achieves: – Drilling fluid supply: Constant-pressure control maintains a stable supply pressure to ensure drilling quality; – Rotational drive: Power control limits rotational load to prevent engine overload; – Mud circulation: High-flow mud circulation (Vg max) enhances drilling efficiency; – Continuous operation: A highly reliable design meets the demands of continuous operations under harsh field conditions.

 

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Chapter 6: Elephant Fluid Dynamics' Supply Chain Advantages and Service Commitments

6.1 Rapid Delivery Capability

Leveraging China's comprehensive hydraulic industry chain and intelligent manufacturing bases, Elephant Fluid Power has established an industry-leading delivery system:

• Standard Models (A11VO60–A11VO95): Regular models are in stock and will be shipped within 48–72 hours after order confirmation.

• Medium to large models (A11VO130–A11VO190): Delivery time: 7–15 working days

• Large models (A11VO220–A11VO260) and special control configurations: Delivery time 15–25 working days

• A11VLO High-Speed Version: Has the same delivery cycle as the corresponding A11VO model and can be optionally equipped with a built-in impeller pump.

• Emergency Response: Direct air freight service available, delivering to major industrial zones worldwide within 72–96 hours.

• Batch OEM Orders: Supports monthly/quarterly rolling inventory planning to ensure customer production continuity

6.2 Cost-Benefit Analysis

Compared to Bosch Rexroth's original products, the Elephant Fluid Power A11VO series delivers significant economic benefits for customers:

• Reduced procurement costs: Direct procurement costs saved by 60%–70%.

• Control System Compatibility: The LR/DR/LRDS/DRS/HD/EP/DH/LG control modes are fully compatible with Rexroth systems, eliminating the need for control system replacement and reducing procurement costs for control valve assemblies by over 50%.

• Optimized accessory costs: All components (cylinder block, plunger, flow distributor, swash plate, control valve core, seals) are available in ample supply at prices only 30%-40% of original factory prices.

• Inventory cost optimization: Supports small-batch, frequent purchases to reduce capital tie-up

• Minimizing downtime losses: Rapid delivery capabilities reduce equipment downtime from weeks to days, with daily losses for construction equipment during peak seasons potentially reaching tens of thousands of yuan.

6.3 Global Technical Support Network

Elephant Hydrodynamics has established a comprehensive technical service network covering major industrial regions worldwide.

• Technical Consultation: Provides 24/7 online selection guidance, system compatibility analysis, and fault diagnosis support. The technical team members have an average of over 15 years of experience and are proficient in all Rexroth product lines.

• Custom Development: Provides solutions tailored to the specific needs of OEM customers.

– Fine adjustment of displacement (e.g., Vg max=135 cm³ instead of the standard 130 cm³)

– Special seals (FKM, HNBR, low-temperature seals)

– Special control methods (e.g., customized pressure range, customized power curve, customized control response)

– Special coatings (marine corrosion-resistant coatings, customer brand logos)

– Customized built-in impeller pump (A11VLO series)

• Warranty Commitment: Standard warranty period is 12 months or 2,000 working hours (whichever comes first), extendable to 36 months upon request. Faulty parts are replaced free of charge during the warranty period; lifetime technical support is provided after the warranty expires.

 

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Chapter 7: Selection Guidelines and Detailed Explanation of Ordering Codes

7.1 Model Coding Rules

The Elephant Fluid Dynamics A11VO series models adhere to internationally recognized coding standards; example: A11VO 130 LRDS / 10R-NZD12K01.

Code segment	Meaning	Option Description
A11VO	Series Identification	Diaphragm-type variable displacement axial piston pump, open circuit, standard version
A11VLO	Series Identification	Diaphragm-type variable axial piston pump, open circuit, high-speed version (with optional built-in impeller pump)
130	Specifications/Maximum Displacement	130 cm³/rev
LRDS	control method	LR = Power control; DR = Constant pressure control; LRDS = Power + pressure cut-off + load sensitivity; DRS = Pressure + load sensitivity; HD = Hydraulic proportional control; EP = Electric proportional control; DH = Hydraulic control (special); LG = Lever control; DH.D = Dynamic hydraulic control; DH.G = Gain hydraulic control; EP.D = Dynamic electric proportional control; EP.G = Gain electric proportional control.
10	serial number	10 = Series 10 (Standard)
R	rotation direction	R = clockwise (viewed from the shaft end); L = counterclockwise
N	sealing material	N = NBR (nitrile rubber); V = FKM (fluororubber, standard)
Z	Axle Type	Z = spline shaft (DIN 5480); P = flat key shaft (DIN 6885); R = spline shaft (ANSI B92.1a)
D	Installation Flange	D = ISO 3019-2, 4 holes; A = ISO 3019-2, 2 holes
12	actuator port	12 = SAE flange oil port, metric thread, laterally opposed; 42 = SAE flange oil port, UNC thread, laterally opposed
K01	Central shaft drive	K01 = Specification code for through-shaft drive flange and hub; N00 = No through-shaft drive

 

7.2 Selection Decision Process

Step 1: Determine System Requirements

-Calculate the system's maximum flow demand: Q_max = Σ (maximum flow rates of all actuators) × simultaneity factor -Calculate the system's maximum operating pressure: p_max = maximum load pressure + pipeline losses + safety margin (typically 10%–15%) -Verify drive motor/engine parameters: rated power, rated speed, maximum torque -Check for high-speed version requirement: if drive speed exceeds 2500 rpm, consider the A11VLO high-speed variant

Step 2: Select pump specifications

Based on the system's maximum flow rate Q_max (L/min) and driving speed n (rpm): Vg_max = (Q_max × 1000 / n) × (1.05–1.10) cm³/rev. The coefficient range of 1.05–1.10 accounts for volume losses and manufacturing tolerances.

Select the model closest to and greater than the calculated value from the standard specifications.

Step 3: Verify Power Matching

Calculated maximum input power of the pump: P_max = Q_max × p_max / (600 × η_t) (kW)

Verification: P_max ≤ Motor/engine rated power × 1.1 (safety factor). If P_max exceeds the motor/engine rated power, select a higher-power drive or a pump with smaller displacement.

Step 4: Select Control Method

-Engine-driven mobility systems (to prevent engine overload) → LR power control or LRDS integrated control; Systems requiring constant pressure → DR constant-pressure control; Systems requiring simultaneous control of power, pressure, and load sensitivity → LRDS integrated control; Systems requiring hydraulic pilot control → HD hydraulic proportional control; Systems requiring electrical signal control → EP electroproportional control; Simple mechanical control → LG lever control; Special control requirements → DH/DH.D/DH.G/EP.D/EP.G special versions

Step 5: Confirm installation conditions

Installation Direction: Horizontal installation of the drive shaft is recommended; for vertical installation (axially up/down), thorough oil filling and air removal are mandatory. Oil Absorption Conditions: Oil suction height ≤ 800 mm, suction pipe diameter ≥ pump inlet diameter, suction filter accuracy ≤ 100 μm. Oil Drain Circuit: Oil should be separately returned to the tank, ensuring housing pressure ≤ 0.5 bar. Oil Viscosity: Select ISO VG22–VG68 based on ambient temperature; optimal operating viscosity range: 16–36 mm²/s. Required Built-in Impeller Pump: Consider using the A11VLO variant with a built-in impeller pump when driving speed exceeds 2500 rpm or under poor oil absorption conditions.

Step 6: Confirm Special Configuration

-Media Type: Mineral oil → Standard FKM seal; HFA/HFB/HFC → NBR seal -Environmental Temperature: Low temperature (<–20°C) → Special low-temperature seal; High temperature (+80°C) → FKM seal with cooler -Shaft Connection Requirements: Requires connected gear pump or auxiliary plunger pump → Select corresponding shaft drive code -Noise Requirements: For high-noise sensitive applications → Choose the low-noise version (with optimized distributor plate) -High-speed Version Required: Drive speed> 2500 rpm → Select the A11VLO high-speed version

 

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Chapter 8: Maintenance, Fault Diagnosis, and Life Management

8.1 Key Points of Daily Maintenance

Oil Management (Most Critical)

Cleanliness grade: Recommended ISO 4406 grades 18/16/13 (equivalent to NAS 7); minimum acceptable grades are 20/18/15 (NAS 9). Oil contamination is the primary cause of failure for the A11VO series. Viscosity management: Optimal operating viscosity range is 16–36 mm²/s. Selection based on ambient temperature: – Low-temperature environment (-20°C to +10°C): ISO VG22 or VG32 – Ambient temperature (+10°C to +40°C): ISO VG46 – High-temperature environment (+40°C to +80°C): ISO VG68. Replacement interval: Mineral oil every 2000 operating hours or annually; eco-friendly oils every 1000 operating hours or semi-annually. Sampling and testing: Viscosity, acid value, moisture content, and contamination level shall be measured every 500 hours or quarterly.

Temperature Monitoring

-Normal operating case temperature: 40°C–70°C -Maximum allowable temperature: 80°C (short-term peak of 90°C, duration <10 minutes) -If the temperature exceeds 80°C, inspect: cooling system, overflow valve settings, internal leaks, and whether oil viscosity is too low

Oil absorption condition monitoring

-Absolute pressure at oil suction port: ≥ 0.8 bar (to prevent cavitation) -Oil suction height: ≤ 800 mm (under standard installation conditions) -Pressure drop across the oil suction filter: ≤ 0.3 bar (exceeding this value requires filter replacement) -Built-in impeller pump (A11VLO version): Check the oil suction port filter to ensure it is free from blockages

Noise and Vibration Monitoring

-Normal noise level: <78 dB(A) (A11VO60-260 specification) - Possible causes of abnormal noise: - High-frequency screeching: Insufficient oil suction (cavitation), distributor plate wear - Low-frequency booming: Bearing wear, coupling misalignment - Irregular knocking: Loose plunger, excessive clearance in swashplate bearing

8.2 Common Fault Diagnosis and Troubleshooting

 

Faultphenomenon	PossibleReasons	Diagnosticmethod	ExclusionMeasures
Insufficient output flow	Excessively low oil viscosity leads to increased internal leakage (due to wear of the distributor plate/plunger), insufficient drive speed, and jamming of the variable mechanism at Vg min.	Measure oil viscosity, determine the return oil flow rate in the housing (normal <5% of Q_in), check drive speed, and verify variable piston displacement.	Replace with appropriate viscosity oil, replace distributor plate/plunger, inspect drive motor/engine, and clean variable displacement mechanism.
Insufficient output pressure	The pressure is set too low, there is internal leakage, the variable mechanism has not reached Vg max, or the relief valve is faulty.	Set the system pressure, measure the oil return flow rate in the housing, check the position of the variable piston, and verify the relief valve.	Increase pressure setting, replace seals, adjust the variable mechanism, and repair/replace the relief valve.
Variable response is slow	Control oil contamination (valve core sticking), insufficient oil pressure, and wear of variable piston seals	Monitor and control oil cleanliness, oil pressure, and piston leakage of variable components.	Replace the control oil filter element, clean the control valve, and replace the sealing of the variable piston.
Abnormal noise	Oil line leakage (cavitation), oil containing gas, bearing damage, wear of flow distribution plate	Check the sealing integrity of the oil suction pipeline, measure the gas content in the oil, and perform vibration spectrum analysis.	Tighten the oil suction lines and exhaust system; replace the bearings and the distributor plate.
Shell oil leakage	Axle seal wear (most common), excessive housing pressure (due to oil drain pipe blockage), seal aging	Check the back pressure of the oil discharge pipe (should be <0.5 bar) and inspect the condition of the shaft seal.	Replace the shaft seal, clear the oil discharge pipe, and replace the sealing components.
superheat	Persistent overload (excessive pressure differential), oil contamination, inadequate cooling, severe internal leakage	Test parameters: pressure differential, oil contamination level, cooler efficiency, and shell return oil flow rate	Reduce load, switch to a larger model, replace the oil, improve cooling, or replace worn components.
Variable control system malfunction	Control valve core jamming, electromagnet failure (EP), pilot oil line blockage (HD)	Measure the resistance of the electromagnet, monitor the oil pressure, and disassemble to inspect the valve core.	Clean or replace the control valve; replace the electromagnet; clear the pilot oil line.
cavitation	Too low oil suction pressure, excessively high oil suction head, blocked oil lines, excessively high oil viscosity, or malfunction of the built-in impeller pump (A11VLO version).	Measure the absolute pressure at the oil suction port, determine the oil suction height, inspect the oil suction filter, measure the oil viscosity, and check the impeller pump (A11VLO version).	Reduce the oil suction height, replace the oil suction filter element, use oil with appropriate viscosity, increase the suction pipe diameter, and repair/replace the impeller pump (A11VLO version).
Power control failure	Power control valve core jamming, power setting mechanism malfunction, contaminated control oil	Measure the displacement of the power control valve core, inspect the power setting mechanism, and check the cleanliness of the control oil.	Clean or replace the power control valve; repair or replace the power setting mechanism; replace the control oil.
Slow response to load sensitivity	LS pipeline blockage, LS valve core jamming, insufficient LS signal pressure	Check the patency of the LS pipeline, inspect the LS valve core, and measure the LS signal pressure.	Clear the LS pipeline, clean/replace the LS valve core, and inspect the LS signal source.

8.3 Predictive Maintenance and Life Management

Key service life parameters: – Distribution plate-cylinder friction pair: Normal service life 12,000–15,000 hours; service life reduced by over 50% when oil contamination exceeds limits – Plunger-sliding shoe friction pair: Normal service life 15,000–20,000 hours; closely related to oil cleanliness and viscosity – Diaphragm bearing system: Normal service life 12,000–15,000 hours; service life extended by static pressure unloading design – Shaft seal: Normal service life 8,000–12,000 hours; closely related to housing temperature and shaft surface roughness – Control valve core: Normal service life 10,000–15,000 hours; closely related to control oil cleanliness – Built-in impeller pump (A11VLO version): Normal service life 8,000–10,000 hours; closely related to oil suction conditions and oil cleanliness

predictive maintenance recommendations: -Install an online oil contamination sensor (ISO 4406 standard) for real-time monitoring; -Measure the return oil flow rate of the housing every 2,000 hours and perform trend analysis on internal leakage rates; -Conduct vibration spectrum analysis every 5,000 hours to detect bearing wear early; -Inspect control oil cleanliness quarterly to prevent valve core sticking; -Check the suction port filter of the built-in impeller pump (A11VLO version) quarterly to ensure it is free from blockages; -Maintain a comprehensive equipment maintenance log recording all replaced parts and oil test data.

 

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Chapter 9: The Industry Value and Strategic Significance of the Elephant Fluid Dynamics A11VO Series

9.1 Redefining the Cost-Performance Criteria for Hydraulic Pumps

Traditionally, high-performance variable-displacement hydraulic pumps have been associated with exorbitant costs. However, Elephant Hydraulics has successfully overturned this perception through the following strategic initiatives:

• Vertical integrated manufacturing chain: From casting, machining, heat treatment to assembly and testing, the entire process is fully controlled internally, reducing outsourcing costs by over 30%.

• Lean production management: By implementing the Toyota Production System (TPS), the production cycle was shortened by 40% and work-in-progress inventory was reduced by 50%.

• Advantages of large-scale procurement: With an annual purchase volume exceeding 100,000 units, key raw materials (bearing steel, copper alloys, seals) are procured centrally, resulting in a cost reduction of 20%-30%.

• Smart Manufacturing Upgrade: Investment in CNC machining centers, assembly lines staffed by employees with 10 years of experience, and automated testing systems, resulting in a threefold increase in per capita output.

Key outcome: The A11VO series delivers performance equivalent to over 95% of that of original Rexroth components at only 25%-35% of their price, creating unprecedented value for customers worldwide.

9.2 Supporting the diversification and resilience of global supply chains

In recent years, the global manufacturing industry has placed unprecedented emphasis on supply chain resilience. As high-quality hydraulic power components manufactured in China, the Elephant Fluid Power A11VO series provides customers in Europe, North America, Southeast Asia, the Middle East, Africa, and South America with a reliable "Second Source" option.

• European Market: Provides OEM components for construction machinery manufacturers in Germany, Italy, France, the Netherlands and other countries, with delivery times of 7–15 days (compared to Rexroth's original 4–8 weeks).

• North American Market: Through our Houston service center in the United States, we provide rapid parts supply services to hydraulic repairers in Texas, California, and Illinois.

• Southeast Asian Market: Service centers in Singapore, Thailand, and Indonesia support the JIT production model of local concrete pump truck and excavator manufacturers.

• Middle East/Africa Market: Service centers in Dubai and Johannesburg support emergency maintenance needs for mining machinery and oil equipment.

• South American Market: The service center in São Paulo, Brazil supports the localized procurement of agricultural and forestry machinery.

9.3 Continuous Technological Innovation and Product Roadmap

Elephant Fluid Dynamics continues to invest in the upgrade and development of its A11VO series. The technical roadmap for the next three years includes:

Material Innovation: – Ceramic-coated plunger: Hardness increased threefold, wear resistance enhanced fivefold, with a target service life of 25,000 hours – Carbon fiber-reinforced斜 disk: Weight reduced by 40%, thermal deformation decreased by 60%, and stability under high-temperature conditions improved – Nano-composite seal: Friction coefficient reduced by 50%, sealing lifespan doubled

Intelligent Integration: -Built-in pressure/temperature/flow sensors: Monitor pump health in real time with data transmitted via CAN bus-IoT data interface: Supports 4G/5G remote data transmission for predictive maintenance-Digital twin system: Establishes a digital model of the pump based on operational data, providing potential fault alerts up to 30 days in advance

Energy efficiency optimization: – CFD fluid simulation-based optimization of flow distribution window design: Reduces flow impact losses, achieving a target total efficiency exceeding 90% – Magnetic rheological variable control: Reduces response time from 0.25 seconds to 0.05 seconds, enabling millisecond-level dynamic response – Energy recovery system: Recovers kinetic energy during braking, reducing overall system energy consumption by 10–15%

Environmental Compliance: – Full compatibility with biodegradable hydraulic fluids: HETG (canola oil-based), HEES (synthetic ester-based), HFD (water-ethylene glycol-based) – Oil-free bearing technology: Exploring applications of air-bearing and magnetic-lift bearings in hydraulic pumps to eliminate oil contamination entirely – Lightweight design: Through topology optimization and aluminum alloy materials, pump weight is reduced by 20–30%, helping customers achieve carbon neutrality goals

 

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Chapter 10: Conclusion and Procurement Recommendations

10.1 Key Conclusions

The Elephant Fluid Dynamics A11VO series variable-displacement axial piston hydraulic pumps (including models A11VO60, A11VO260, and the high-speed A11VLO version) feature the following advantages:

1. Comprehensive specification range: covering volumes from 60 cm³ to 260 cm³, meeting all requirements for both small-to-medium engineering machinery and ultra-heavy mining equipment.

2. High compatibility with original Bosch Rexroth products: 100% physical interchangeability, over 95% performance equivalence, and full replication of all control methods.

3. Proven reliable performance: over 15,000 hours of continuous operating life, 95% volumetric efficiency, and total efficiency exceeding 87%.

4. Highly competitive supply chain advantages: 60%-70% cost savings, rapid delivery within 48 hours to 25 days, and a service network covering six continents worldwide.

5. Continuous technological innovation capability: simultaneous advancement in four key areas—materials, intelligence, energy efficiency, and environmental protection.

It has become the preferred alternative in the global hydraulic power transmission industry. Whether for original equipment manufacturing (OEM) applications or after-sales maintenance/replacement needs, and whether for cost-sensitive budget-friendly systems or high-end equipment demanding ultimate reliability, the Elephant Fluid Power A11VO series delivers a tailored value proposition.

10.2 Recommendations for Procurement Decisions

For engineering machinery manufacturers (OEMs): -Start with small-scale trial installations (5–10 units) to verify compatibility with existing systems; -Utilize Elephant Hydraulics' free technical consulting services to optimize system integration (pump–motor–valve–pipelines); -Sign annual framework agreements to lock in prices and delivery schedules, ensuring production continuity; -Consider incorporating Elephant Hydraulics into a "dual-supply-source" strategy to mitigate supply chain risks; -For core products such as concrete pump trucks and excavators, adopt LRDS integrated control directly for optimal energy efficiency.

For hydraulic system integrators: -Recommend the Elephant Hydraulics A11VO series as a standard configuration option to end customers; -Leverage rapid delivery capabilities (shipments within 48 hours) to handle emergency orders and maintenance projects; -Participate in Elephant Hydraulics' technical training programs (online/offline) to enhance team expertise; -Maintain comprehensive spare parts inventories (cylinder blocks, plungers, flow plates, swash plates, control valve cores, seals) to improve maintenance response efficiency.

For end-users (mining, construction, industrial sectors, etc.): – During major equipment overhauls, consider replacing Rexroth original pumps with Elephant Fluid Power's A11VO series to reduce maintenance costs by over 60%; – Maintain the existing control system (LR/DR/LRDS/DRS/HD/EP valve assemblies) without additional investment; – Access local technical support through Elephant Fluid Power's global service center; – Establish equipment maintenance records and implement predictive maintenance to maximize pump service life.

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Appendix

Appendix A: Complete Model Reference Table for the A11VO/A11VLO Series

 

Model	MaximumDisplacement(cm³)	Nominalpressure (bar)	PeakPressure (bar)	MaximumSpeed@Vgmax(rpm)	Maximumrotationalspeed@Vg≈0(rpm)	MaximumFlowRate (L/min)	Maximumpower@350bar(kW)	weight (kg)	FlangeSpecifications	AxleEndOptions	Controlmethod	Optionalimpellerpump
A11VO60	60.0	350	400	3300	3900	198.0	115.5	28	ISO 2-hole/4-hole	Flat Key/Spiral Key	LR/DR/LRDS/DRS/HD/EP/DH/LG	deny
A11VO75	75.0	350	400	3000	3600	225.0	131.3	32	ISO 2-hole/4-hole	Flat Key/Spiral Key	LR/DR/LRDS/DRS/HD/EP/DH/LG	deny
A11VO95	95.0	350	400	2700	3100	256.5	149.6	38	ISO 2-hole/4-hole	Flat Key/Spiral Key	LR/DR/LRDS/DRS/HD/EP/DH/LG	deny
A11VO130	130.0	350	400	2500	2900	325.0	189.6	48	ISO 2-hole/4-hole	Flat Key/Spiral Key	LR/DR/LRDS/DRS/HD/EP/DH/LG	deny
A11VO145	145.0	350	400	2400	2800	348.0	203.0	52	ISO 2-hole/4-hole	Flat Key/Spiral Key	LR/DR/LRDS/DRS/HD/EP/DH/LG	deny
A11VO190	190.0	350	400	2200	2600	418.0	243.8	68	ISO 2-hole/4-hole	Flat Key/Spiral Key	LR/DR/LRDS/DRS/HD/EP/DH/LG	deny
A11VO220	220.0	350	400	2000	2400	440.0	256.7	78	ISO 4 holes	Flat Key/Spiral Key	LR/DR/LRDS/DRS/HD/EP/DH/LG	deny
A11VO260	260.0	350	400	1800	2100	468.0	273.0	95	ISO 4 holes	Flat Key/Spiral Key	LR/DR/LRDS/DRS/HD/EP/DH/LG	deny
A11VLO60	60.0	350	400	3900	4500	234.0	136.5	30	ISO 2-hole/4-hole	Flat Key/Spiral Key	LR/DR/LRDS/DRS/HD/EP/DH/LG	deny
A11VLO75	75.0	350	400	3600	4200	270.0	157.5	34	ISO 2-hole/4-hole	Flat Key/Spiral Key	LR/DR/LRDS/DRS/HD/EP/DH/LG	deny
A11VLO95	95.0	350	400	3100	3600	294.5	171.8	40	ISO 2-hole/4-hole	Flat Key/Spiral Key	LR/DR/LRDS/DRS/HD/EP/DH/LG	deny
A11VLO130	130.0	350	400	2900	3400	377.0	219.9	50	ISO 2-hole/4-hole	Flat Key/Spiral Key	LR/DR/LRDS/DRS/HD/EP/DH/LG	yes
A11VLO145	145.0	350	400	2800	3300	406.0	236.8	54	ISO 2-hole/4-hole	Flat Key/Spiral Key	LR/DR/LRDS/DRS/HD/EP/DH/LG	yes
A11VLO190	190.0	350	400	2600	3100	494.0	288.2	70	ISO 2-hole/4-hole	Flat Key/Spiral Key	LR/DR/LRDS/DRS/HD/EP/DH/LG	yes
A11VLO220	220.0	350	400	2400	2900	528.0	308.0	80	ISO 4 holes	Flat Key/Spiral Key	LR/DR/LRDS/DRS/HD/EP/DH/LG	yes
A11VLO260	260.0	350	400	2100	2600	546.0	318.5	97	ISO 4 holes	Flat Key/Spiral Key	LR/DR/LRDS/DRS/HD/EP/DH/LG	yes

Appendix B: Quick Reference Table for Selecting Control Methods

Control method	Code	Control signal	Control range	Response speed	Applicable Model	Typical Application
power control	LR	Built-in mechanical valve	power limitation	Middle	60-260	Excavators, loaders, bulldozers
Constant Pressure Control	DR	Built-in mechanical valve	pressure limitation	Middle	60-260	Clamping device, test bench, concrete pump truck
Power + Pressure + Load Sensitivity	LRDS	Built-in mechanical valve + LS	Power + Pressure + Flow Rate	Middle	60-260	Large excavators, concrete pump trucks, mining trucks
Pressure and Load Sensitivity	DRS	Built-in mechanical valve + LS	Pressure + Flow Rate	Middle	60-260	Crane; High-altitude work platform
Hydraulic Ratio	HD	Hydraulic Leader	Vg min-Vg max	fast	60-260	Pilot control systems for excavators and loaders
Electrical Ratio	EP	12V/24V DC	Vg min-Vg max	fast	60-260	Automated equipment, remote control devices, CNC equipment
Special Hydraulic Control	DH	Hydraulic Pilot (Special)	custom made	fast	60-260	Ship hydraulic systems, aviation ground equipment, military equipment
Mechanical Lever	LG	Mechanical Lever	Vg min-Vg max	slow	60-260	Small agricultural machinery; simple construction equipment
Dynamic Hydraulic Control	DH.D	Hydraulic Pilot (Dynamic)	custom made	Extremely fast	60-260	High-speed injection molding machines, high-speed die-casting machines
Gain Electric Proportion	EP.G	Electrical Ratio (Gain)	custom made	Extremely fast	60-260	Servo hydraulic systems, CNC machining centers

Appendix: References and Standards

6. Bosch Rexroth AG. “Axial Piston Variable Pump A11VO, Data Sheet.” 2016.

7. Bosch Rexroth AG. “Axial Piston Variable Pump A11VLO, Data Sheet.” 2016.

8. ISO 3019-2:2001. “Hydraulic fluid power - Dimensions and identification code for mounting flanges and shaft ends of displacement pumps and motors.”

9. ISO 4409:2019. “Hydraulic fluid power - Positive-displacement pumps, motors and integral transmissions - Methods of testing and presenting basic steady state performance.”

10. ISO 4406:2021. “Hydraulic fluid power - Fluids - Method for coding the level of contamination by solid particles.”

11. ISO 6162:2002. “Hydraulic fluid power - Flange connections with split or one-piece flange clamps and metric or inch screws.”

12. DIN 51524. “Pressure fluids - Hydraulic oils HL, HLP, HLPD.”

13. DIN 6885. “Drive type fastenings without taper action; Parallel keys, keyways, deep pattern.”

14. ANSI B92.1a. “Involute Splines and Inspection.”

15. Hydrodynamics of Elephants. "Product Manual for A11VO/A11VLO Series Variable Axial Piston Pump," 2026 edition.

16. China Hydraulic and Pneumatic Seals Industry Association. "Technical Development Report of the Variable Hydraulic Pump Industry." 2025.

17. TUV Rheinland. “Performance Test Report for Elephant Fluid Power A11VO Series.” 2025.

 

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Copyright © 2026 Elephant Fluid Dynamics

This document is for technical communication and selection reference only. Specific parameters should refer to the latest product manual.

 

 

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This document was compiled by Elephant Hydraulics to provide the global hydraulic industry with authoritative, professional, and comprehensive technical references. We are committed to becoming your most trusted hydraulics partner through technological innovation and exceptional service.