Claas Lexion 480-405 Technical Systems, Hydraulic System PDF Manual

LEXION II General hydraulics
Oil change: First change after the first 100 operating hours, then either yearly or every 500 hours whichever is sooner. Check the oil level with the cutterbar rams retracted.

Claas Lexion 480-405 Neutral function
In the neutral position, the oil flows through the one way valve (742) and the rotary valve (609) and back to tank (open centre). The back pressure must not exceed 20 bar. Both ends of the steering rams (323) are locked by the valve (609). Pressure spikes caused by external influences, are eliminated by the shock valves (725), which opens to tank (Non reaction).

Claas Lexion 480-405 Service and Parts
By turning the steering wheel in one direction or the other, causes the inner spool (609) to turn up to 8° to the outer spool (609). This causes the return from the pump (218) to tank to be closed and the connection to the measuring unit (229) is opened.

The oil flow rate is dependent on the rotation, amount and speed of the rotor (229) and the rotary valve (609) to the ram of ram ring flange of the steering rams (323). The displacing flange area of the ram (323) is thus connected via rotary valve (609) to the return flow to the tank.

As soon as the steering wheel is released, the springs return the inner and outer spool (609) back to the neutral position. As soon as they are returned to the neutral position, then either end on the ram is locked and the connection between pump (218) and tank re-instated.

Claas Lexion 480-405 Service Manual
When the steering pump (218) fails to deliver oil to the steering system, the one way valve (742) closes, ensuring that no oil can flow out from the system. Operating the steering wheel in one direction or the other will turn the inner and outer spool (609) in an opposite direction. Oil is then pumped by the rotor (229) using muscel power from one side of the steering ram (323) to the other, via the one way valve (728). Machines that are only equipped with one ram (323), require the reservoir as one side of the ram has a different surface area to the other.

Claas Lexion 480-405 hydraulics System
Should the pressure in the accumulator drop below 135 ± 5 bar when the engine is running, then the oil pressure switch (B5/Z4) on the returns valve is operated. This causes the system pressure to be switched to the accumulator (503) via the one way valve (732). When the system pressure is present, and the accumulator has been charged to 160 ± 5 bar, the oil pressure switch (B5/Z4) opens and the returns valve switches back into the neutral position. The one way valve (732) separates the stored energy and the systems working hydraulics.

The stored pressure is held in the closed system and lies on the balls of the two solenoid valves (Y9/Y10).

The module for the autopilot system will switch one of the solenoid valves (Y9/Y10), depending on steering direction required. The valve pin then presses down on the ball within the valve cartridge and shuts off the return line to the tank. The pressure then pushes against the ram and opens the one-way valve at A or B. The return oil from the ram is then switched via the non-operated solenoid valve (Y9/Y10) back to the tank. The pressure increasing further now opens the opposite one-way valve and the steering cylinder is retracted or extended.

When the required angle for the steering has been achieved, then the Autopilot module switches off the solenoid valve (Y9/Y10). Should the pressure in the accumulator (503) fall below the 135 ± 5 bar due to steering demands, then the pressure switch (B5/Z4) will operate, the returns valve will be switched and pressure will be reinstated to the accumulator (503).