Bosch Rexroth A8VO225 series 72 axial piston double hydraulic pump

The A8VO225 is a variable-displacement axial piston double pump built for open-circuit hydrostatic drives. "Double pump" doesn't mean two separate units bolted together — it means two independent bent-axis rotary groups sharing one housing, one drive shaft, and one suction port, each feeding its own hydraulic circuit. That's what lets a single engine-mounted unit run two completely separate functions — say, a swing circuit and a boom circuit — without cross-talk between them.

"225" is the size designation (NG 225), referring to the geometric displacement per rotary group. "Series 72" identifies the design generation, which governs mounting dimensions, port locations, and control options — important to know because a Series 72 unit won't necessarily swap in for an older or newer series without checking the installation drawing.

How the A8VO225 Series 72 Actually Works

Bent-Axis Rotary Groups, Not Swashplate

Unlike some axial piston pumps that tilt a swashplate while the cylinder block stays fixed, the A8VO uses a bent-axis design: the entire cylinder block pivots relative to the drive shaft. Swiveling the rotary group changes the piston stroke, which changes displacement — and because flow is directly proportional to displacement and shaft speed, this is what gives the pump its stepless, infinitely variable output from zero up to maximum flow.

Both rotary groups sit in the same housing but pivot independently, which is the mechanical basis for the "double pump" behavior: circuit 1 can be running at full displacement while circuit 2 is nearly at zero, with no interference between them.

Individual Power Control (the LA1 Family)

The A8VO225 Series 72 is offered with individual power controllers, most commonly designated LA1KH1 (negative control) or LA1KH2 (positive control, external pilot pressure). Here's what that means on the shop floor:

Each rotary group has its own power controller, and each can be set to draw up to 100% of the engine's available power on its own.

With the hydraulic coupling (K) feature, the two controllers "talk" to each other through pilot pressure — if one circuit is only using, say, 30% of its share of engine power, the other circuit can borrow the unused capacity, up to the full drive power in extreme cases.

The H1/H2 hydraulic stroke limiter lets an operator or control system limit displacement independently of the power setting, using a pilot pressure signal at port X1 (up to 40 bar).

Power override at port X3 allows an external electronic controller — Bosch Rexroth's BODAS system is the typical example — to trim the power setting on the fly, which is how many OEMs implement load-sensing or engine-protection strategies.

Auxiliary Pump and Power Take-Off

The A8VO225 can be ordered with an integrated auxiliary (pilot) pump, drawing from the same shared suction port as the two main circuits, protected by a fixed 30 bar pressure-relief valve. This auxiliary flow typically feeds the pilot control system — joystick pilots, solenoid valves, and the like — so the machine doesn't need a separate pilot pump bolted on elsewhere.

There's also a power take-off (PTO) provision on the back of the unit, rated up to 800 Nm, which lets manufacturers hang an additional axial piston or gear pump off the same drive train — useful for a third circuit, such as a cooling fan drive or an attachment circuit, without adding another engine-mounted pad.

Real-World Examples

Large hydraulic excavators (40+ tonne class). This is the pump's home territory. One rotary group typically feeds the boom/arm/bucket circuit, the other feeds swing and travel. The LA1K hydraulic coupling is especially valuable here: a digging cycle involves rapid, uneven demand between functions, and letting the two circuits share engine power keeps cycle times short without oversizing the engine.

Crawler cranes and piling rigs. These machines often run a hoist circuit and a slewing or auxiliary winch circuit simultaneously. The A8VO225's high pressure rating (380 bar continuous) suits the sustained high loads of lifting and drilling operations, and the PTO option lets crane builders add a dedicated pump for outrigger or luffing functions.

Drilling equipment. Rotary drive and mud pump circuits both demand precise, independently variable flow — exactly what two decoupled rotary groups in one housing provide, without needing two separate engine-mounted pumps and the extra mounting hardware that implies.

For more information on the A8VO225 hydraulic pump, please visit https://www.baolilaihydraulic.com/product/.

Specifications

Selection Table

Q1: What does "Series 72" mean on an A8VO225?

A1: It identifies the design generation within the A8VO product line — Series 7, index 2. It affects mounting dimensions, port arrangement, and available control options, so parts and replacement units should be matched by series, not just by size.

Q2: Is the A8VO225 an open-circuit or closed-circuit pump?

A2: Open circuit. It draws from and returns to a reservoir rather than circulating in a closed loop with a motor, which is why it's specified for excavators, cranes, and drilling rigs rather than pure hydrostatic transmissions.

Q3: How to purchase an A8VO225 hydraulic pump?

A3: You can visit https://www.baolilaihydraulic.com/contact/ to contact us and purchase our products through various methods.

Q4: What is the price and delivery time of the A8VO225 hydraulic pump?

A4: The specific price and delivery time will be provided based on the specific model you provide.