REXRTOH A4VG series 40 axial piston variable displacement pump application guide

REXRTOH A4VG series 40 axial piston variable displacement pump application guide

In modern walking machinery, engineering machinery, and heavy industrial equipment, hydraulic systems are the heart that generates powerful power. As its core power source, the performance of the axial piston pump directly determines the efficiency, response speed, and reliability of the entire system. The A4VG Series 40 axial piston variable displacement pump launched by Bosch Rexroth is designed for closed circuit applications with working pressures up to 500 bar. With its extremely high power density, rich control options, and sturdy and durable structure, it has become a benchmark product in the high-end hydraulic drive field. This article will deeply analyze its technical characteristics, control principles, selection standards, and application points.

Core Features and Design Advantages

The design concept of the A4VG Series 40 pump is to achieve maximum power output and compact structure. Its core advantages include:

Ultra high working pressure: The rated pressure can reach up to 450 bar, and the maximum pressure can reach 500 bar, significantly improving the system power density and helping to miniaturize the equipment.

Variable design of inclined disc: By changing the inclination angle of the inclined disc, the displacement can be infinitely adjusted. When the flow direction changes, the inclined disc smoothly passes through the center position, ensuring smooth operation and minimal impact.

Integrated auxiliary pump: Equipped with a built-in gear type oil replenishment pump, it provides necessary replenishment and pilot control oil source for closed circuits. It can also choose the version without a built-in oil replenishment pump, which is supplied by an external oil source.

Through drive shaft: allows for the installation of a second pump of the same diameter in series on the same axis, providing a compact solution for multi circuit systems without the need for a transfer case.

High performance high-pressure safety valve: Integrated oil replenishment function, direct acting, used to protect pumps and motors from overload pressure impact.

Diversified control methods: providing comprehensive control options from pure hydraulic to electro-hydraulic proportional, from manual to automatic speed related (DA control), to meet various application needs from simple to complex.

Interpretation of Technical Parameters and Selection Codes

1. Displacement and specifications

This series offers six specifications (NG) and geometric displacement (at 20 bar) to meet a wide range of needs:

NG 110: 110.4 cm³/rev

NG 125: 125 cm³/rev

NG 145: 145.3 cm³/rev

NG 175: 175.4 cm³/rev

NG 210: 210.6 cm³/rev

NG 280: 280 cm³/rev

Each specification comes with standard speed and high-speed (some specifications) rotor sets to meet different speed and power requirements. Its weight (excluding through drive) ranges from approximately 88 kg (NG110) to 152 kg (NG280).

2. Selection code: embodiment of modular configuration

The A4VG pump adopts a selection code of up to 23 digits, achieving high customization. The core code includes:

04- Control mode: This is the core of the selection, determining the control logic of the pump.

HP: Hydraulic proportional control, related to pilot pressure (6-18 bar). The external pilot pressure signal directly controls the displacement, and the flow rate can be ignored.

HW: Hydraulic proportional control, mechanical servo with lever. The displacement is continuously controlled through an external mechanical lever angle (± 3 ° to 32 °), with standard spring centering.

HT: Hydraulic direct control. The control pressure directly acts on the variable piston, and the displacement is related to the control pressure, system pressure, and speed.

DA: Automatic control, related to speed. The built-in DA control valve generates pilot pressure based on the driving speed to achieve adaptive adjustment of engine power, commonly used for walking drive.

EP: Electro hydraulic proportional control. Stepless control of displacement through input current (such as 400-1200mA for 12V systems), optional with manual emergency operation version.

EZ: Two point electronic control. Switch the displacement between zero and maximum through power on/off control.

ET: Direct electronic control. The pressure acting on the variable piston is controlled by the current of two proportional pressure reducing valves (DRE).

05- Pressure cutoff: optional function. When the set pressure is reached, pull the pump displacement back to the minimum to prevent frequent opening of the high-pressure relief valve, save energy, and reduce heat generation. It must be set at least 30 bar below the set value of the high-pressure safety valve.

17- Oil replenishment pump and rotor assembly configuration: Standard or high flow built-in gear oil replenishment pump can be selected, or no built-in oil replenishment pump can be selected (supplied by external oil).

18- Through drive: Specify the installation flange (SAE J744 standard) and spline shaft specifications (ANSI B92.1a or DIN 5480) for connecting the second pump in series.

20- Oil replenishment circuit filtration/external oil replenishment: Optional solutions include oil suction pipeline filtration (S), oil pressure pipeline filtration (D), accessory filter (F/B), or external oil replenishment supply (E).