THEORY OF OPERATION - CONTINUED
ELECTRO-HYDRAULIC SYSTEM - CONTINUED
Ride control valve (89) provides dampening for forces produced by bucket as machine travels over rough terrain.
Ride control valve has three positions: AUTO, OFF, and SERVICE.
Ride control valve (89) contains ON/OFF solenoid valve (112), which is an ON/OFF switch which works with
shuttle valve (110) to charge ride control accumulator (97). When accumulator is being charged, check valve (111)
allows pump oil to enter ride control valve through shuttle valve. Oil exits ride control valve through connector to
charge ride control accumulator.
When ride control accumulator (97) is not being charged, check valve (111) keeps oil from ride control circuit
from returning to main hydraulic system. If oil pressure rises above ride control relief valve (103) setting, relief
valve opens to allow excess pressure to drain to hydraulic tank through tank port (C).
Ride control valve also contains solenoid valves (93 and 96). When ride control system is activated, drift reduction
solenoid valve (93) allows oil to enter ride control valve from rod end of tilt cylinder at work port. Oil exits ride
control valve at tank port (D). Solenoid valve (96) works with ride control check valve to allow oil from head end
of lift cylinder to mix with oil from ride control accumulator (97) at head end lift cylinder work port. Nitrogen gas
in ride control accumulator acts as a shock absorber for lift circuit.