1. Product Overview

LRDS Valveis from the Rexroth A11VO seriesSwashplate axial piston variable pumpTheCore control component, with the full name ofLoad sensing, pressure cut-off, electro-proportional composite control valve. It is aHydraulic control valve block integrated on the pump body (usually flange connection).

Application: In roadheaders and shearers, this valve is responsible for controlling the force and speed of actions such as walking and cutting arm lifting, and is the core of the equipment's power output.

2. Core Function Analysis

The LRDS valve usually integrates three core functions:

A. Electro-proportional displacement control

• Remote control: By inputtingA current signal of 0.8A / 1.05A(instead of a mechanical lever) to control the pump's displacement.

  
  

• Precise adjustment: The current magnitude directly corresponds to the swashplate inclination angle, thus steplessly adjusting the output flow. This makes the actions of the roadheader (such as walking speed and drum lifting) very delicate, rather than simply "on" or "off".

  
  

B. Load sensing control

• Oil supply on demand: The valve continuously detects the systemHighest working pressure (load pressure).

  
  

• Energy-saving and efficient: The pump always outputs a pressure of "load pressure + constant pressure difference (about 20 bar)". When the load is light, the pump's pressure automatically decreases; when the action stops, the pump automatically enters the standby state. This greatly reduces the heat generation and energy consumption of the hydraulic system, which is crucial for roadheaders working for a long time.

  
  

C. Pressure cut-off control

• Overload protection: When the system pressure reaches the setCut-off value(such as 280 bar or 350 bar), the valve will force the pump to reduce the displacement to nearly zero.

  
  

• Soft unloading: Different from direct overflow, this method avoids high-pressure shocks, protects hydraulic pipelines and seals, and prevents pipe bursts or oil leaks.