A11VO for excavator

The A11VO is a swashplate-type axial piston main pump developed by Rexroth specifically for open-loop hydraulic systems in excavators. It covers the full range of tonnage, from 6-metric-ton mini excavators to 50-metric-ton heavy-duty mining excavators, and serves as the standard main oil pump for mainstream excavators both domestically and internationally.

First, Core Advantages for Excavator Operating Conditions

1. LRDS Constant Power + Load-Sensitive Hybrid Control (Standard on Excavators)

It dynamically matches engine power in real time and automatically allocates flow for combined operations (lifting + slewing + travel), preventing stalling and black smoke emissions. Compared to older fixed-displacement pumps, it achieves 15%–30% fuel savings; with a variable response time of <100 ms, operations are smooth without stuttering or impact.

2. High-Pressure, Heavy-Duty Durability

Rated continuous operating pressure of 350 bar, with a short-term peak of 400 bar, suitable for the impact loads of excavation, crushing, and heavy-duty loading operations; pistons, slide shoes, and distribution plates feature wear-resistant coatings to withstand dusty, high-temperature, and harsh job site environments.

3. In-Line Integrated Pilot Pump

A pilot gear pump is directly connected in series to the rear of the main pump. A single engine power source simultaneously supplies both the main hydraulic system and the control pilot circuit, saving installation space in the cab and reducing the number of pipes and components.

4. Stable Operation in High and Low Temperatures

The A11VLO with oil replenishment features a cold start without cavitation noise; an independent drain circuit rapidly dissipates frictional heat, keeping oil temperature under control during prolonged continuous excavation.

5. Dual-Pump Parallel Operation Support (for Heavy-Duty Excavators)

When two A11VO pumps of the same specification are paired with LRC cross-power control, total power is evenly distributed; power from an idle pump is fully supplied to the other pump, enhancing the speed of combined movements.

Second, Structural Logic of the Excavator Hydraulic System

1. Power Input: The engine’s power take-off (PTO) elastic coupling drives the A11VO main shaft;

2. Shaft Output: A pilot gear pump is connected in series to the pump tail to provide pilot pressure for the control levers;

3. Main Oil Circuit Port A: High-pressure oil is delivered to the multi-way distribution valve to drive the boom, stick, bucket, swing, and travel motors;

4. LS Feedback Circuit: Load pressure from the multi-way valve is fed back to the pump’s LS port to adjust the pump’s displacement in real time;

5. Independent drain port T: Lubricating oil from the pump housing’s friction pairs returns separately to the tank with a back pressure ≤0.5 bar to prevent damage to the skeleton oil seals;

6. A11VLO built-in oil replenishment: The impeller continuously supplies oil to the suction chamber, eliminating cavitation noise during high-speed excavation.

Third, Special Installation Specifications for the A11VO Excavator

1. Extremely High Coaxiality Requirements for the Drive

Excavators experience significant vibration; therefore, a flexible coupling must be used, with radial misalignment ≤ 0.1 mm. Rigid direct connection is prohibited, as it can easily cause spline wear or shaft breakage.

2. Preventing Air Leaks in the Suction Line (A Common Failure Point in Excavators)

For micro/medium-sized A11VO units, the suction vacuum must be ≤ 0.8 bar; the suction line should be short, straight, and have minimal bends; Air leaks can cause weak digging power, screeching noises, and rapid piston damage; models 190/260 must use the A11VLO for forced oil replenishment.

3. Mandatory Steps for Filling and Bleeding the Housing

After prolonged downtime or pump replacement/repair, hydraulic oil must be added through the drain port, and the pump must be manually cranked to expel all air. Never start the engine directly, as dry running will burn out the distribution plate.

4. Dedicated Drain Line Back to the Tank

Do not share the drain line with the multi-way valve return line. High back pressure from the excavator’s high-flow return line can cause pump seal leaks and housing overheating.

Our company has extensive production experience with the A11VO for excavators. Our products not only offer excellent quality but also provide great value for money. We have customers in more than 30 countries worldwide, many of whom are repeat customers. If you are interested in purchasing, please contact us.

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