Bosch Rexroth A10VG closed-circuit hydraulic pump for Hamm road roller 02057222 2057226 2057501 1298437 2034596 02057227 1285688

The A10VG is a variable-displacement axial piston pump built specifically for closed-circuit hydrostatic transmissions. It's part of Rexroth's broader family of swashplate pumps (which also includes the A4VG and A10VO), but the "G" designation marks it as purpose-built for closed-loop drive circuits rather than open-circuit auxiliary systems.

Key Design Features

Swashplate-driven variable displacement — output flow scales smoothly from zero to maximum as the swashplate angle changes, giving infinitely variable travel speed with no shift points.

Bidirectional flow — the pump reverses flow direction as the swashplate passes through neutral, letting the roller move from forward to reverse without a separate reversing valve.

Integrated charge (boost) pump — an internal gear pump mounted on the same shaft supplies makeup oil and pilot pressure, replacing internal leakage and keeping the closed loop primed.

Dual high-pressure relief valves — these double as boost pressure valves, protecting both the pump and the drive motor from shock loads and overload.

Multiple control options — mechanical pivot control, hydraulic (pilot-pressure) control, electric proportional control, and speed-related electronic control, depending on how the OEM wants the operator interface to behave.

Frame sizes 18–63 — referring to maximum geometric displacement in cm³ per revolution, sized to match the roller's weight class and travel speed requirements.

Why Hamm Uses the A10VG for Roller Propel Systems

Hamm AG, part of the Wirtgen Group, builds everything from 1.5-ton pedestrian plate compactors up through 25-ton pneumatic-tire and tandem asphalt rollers. Across nearly all of them, hydrostatic drive — built around Rexroth pumps like the A10VG — has replaced mechanical transmissions almost entirely. There are practical reasons for that.

Stepless Speed Control

A roller doesn't need five forward gears. It needs to creep along a fresh mat at a precise, constant speed the operator can dial in and hold — because compaction quality depends heavily on consistent passes at a consistent speed. The A10VG's swashplate gives that: turn the control lever and displacement (and therefore speed) changes smoothly, with no clutch engagement and no jerk at low speed.

Smooth Forward-Reverse Transitions

Rollers reverse direction constantly, often every 30–60 seconds during a compaction pass. A geared transmission takes a beating under that duty cycle. Because the A10VG's swashplate simply sweeps through neutral and out the other side, direction changes happen without shock loading a clutch or gear train — which is a major reason hydrostatic drives outlast mechanical ones in this application.

Compact Packaging

Rollers are tightly packaged machines — engine, drums, water tanks, and vibration systems all compete for space in a short wheelbase. An axial piston pump bolted directly to the engine's PTO or flywheel housing takes up far less room than a mechanical transmission and driveshaft arrangement, and it can be mounted in almost any orientation.

Load-Sensing Overload Protection

Compaction work throws unpredictable loads at the drivetrain — a roller climbing a grade, working against a curb, or hitting a soft subgrade. The A10VG's built-in pressure relief and boost valves absorb those spikes automatically, protecting the motor and driveline without operator intervention.

How the A10VG Fits Into the Broader Hydraulic System

It helps to see the pump in context rather than in isolation.

The Hydrostatic Loop

Engine → A10VG pump → high-pressure hoses → hydraulic travel motor → drum or wheel → return line → back to the A10VG. The charge pump taps off the same shaft to draw filtered oil from the reservoir and inject it into the low-pressure side of the loop, replacing any oil that leaks past the pistons and valve plate.

The Control Signal Path

Depending on the control device fitted, the operator's speed/direction command reaches the pump in one of several ways:

Mechanical (MD) — a direct linkage from the control lever to the swashplate.

Hydraulic (HD/HW) — a pilot-pressure signal, generated by a joystick-operated pilot valve, moves the swashplate via a servo piston.

Electric (DA1/DA2) — a proportional solenoid, commanded by the machine's electronic control unit, sets displacement — common on newer Hamm rollers with electronic drive management.

Cooling and Filtration

Because the same oil recirculates continuously in the closed loop, both heat and contamination are of enormous importance. Hamm rollers route a portion of case-drain and charge flow through a cooler before it returns to the reservoir, and Rexroth specifies fairly strict cleanliness targets — typically ISO 4406 class 20/18/15 or better — because axial piston pumps run with extremely tight piston-to-bore clearances that don't tolerate abrasive contamination.

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Q1: What frame sizes of A10VG are used in Hamm rollers?

A1: Roller applications commonly use the 18, 28, 45, and 63 cm³ displacement sizes, chosen based on the roller's weight class and required travel speed. Smaller pedestrian and articulated rollers use the smaller frames; heavier tandem and pneumatic-tire rollers typically use the larger ones.

Q2: What's the typical service life of an A10VG in a road roller?

A2: With clean fluid, proper filtration, and normal duty cycles, these pumps commonly run for several thousand hours before needing a rebuild. Actual life varies significantly with fluid cleanliness, operating temperature, and how often the machine is stalled against loads — factors well within an owner's control.

Q3:What is the price and delivery time of the A10VG hydraulic pump for the Hamm road roller？

A3: The specific price and delivery time will depend on the equipment model or specific product model you provide.

Q4:How to purchase an A10VG hydraulic pump for the Hamm road roller?

A4:You can visit https://www.baolilaihydraulic.com/contact/ to contact us and purchase our products through various methods.