2) 2) OPERATION OPERATION (1) (1) Neutral Neutral KV1 18A 7607SE12 В In neutral position, the oil will pass from the pump across the integrated priority valve (18) in the steering valve for discharge through the EF port. When the steering unit is in neutral, flow through it is blocked and all flow through the priority valve (18) in steering valve is directed out the EF port and passed to the main control valve. В When the engine is turned off, the priority valve spool (18) is pushed to the right by the spring. The passage to the EF port is blocked while the passage to the CF port is open. В When the machine is started, EF port of the steering valve may be connected to the working hydraulic.
Maximum pressure on the EF port = 250 bar . В The operating pressure in the loader system has not effected on the operation of the priority valve(18) of steering valve. Independently of operation of the loader actuated in relief, the priority valve(18) will not shift until the machine is steered. В A part of flow through the priority valve spool (18) will flow to P port of steering unit through pres- sure reducing valve. Also flow as pilot signal of steering through the priority valve spool (18) pass- es from the P port through the dynamic orifice and into the LS line. It flows to the tank through the LS orifice in main spool.
В In neutral position, the main spool will be in its center position. This means that knocks and impacts from the cylinder are not transmitted to the steering unit. The steering valve is thus of the non-reaction type. 5-7 CL S3 CF LS P 18 CR Shock valves Suction valves 15 KV2 17 16 Ps Pressure L R reducing valve P T Ts EF T