Group 1 Structure And Function - Hyundai HL955 Manual

GROUP 1 STRUCTURE AND FUNCTION

GROUP 1 STRUCTURE AND FUNCTION
1. OUTLINE 1. OUTLINE
The variable displacement piston pump supplies the hydraulic oil that is required in order to operate
the brake and the hydraulic fan system. Oil flows from pump to the cut-off valve.
The cut-off valve controls the flow of oil from the pump to the brake accumulators and also controls
the flow of oil to the hydraulic fan motor.
The cut-off valve contains a priority valve. The brake system has priority. The oil flows to the brake
accumulators while the accumulators are charged. After the accumulators are fully charged, the oil
then flows to the hydraulic fan system.
The accumulator has pre-charged gas and an inlet check valve to maintain a pressurized volume of
oil for reserving brake system.
The oil through the accumulator flows to the brake valves. The brake valve is a closed center design,
dual circuit operated by a pedal.
The front and rear brakes will operate simultaneously with only one brake pedal depressed.
The hydraulic fan system is used to meet the cooling requirements. The hydraulic fan system controls
the fan speed through the pump output pressure. The desired pressure level can be set by varying
the solenoid current.
The hydraulic fan system contains directional valve that reverses the direction of fan.
The brake and hydraulic fan system contains the following components :
·Fan & brake pump
·Cut-off valve
·Brake valve
·Accumulators
·Pressure sensors and switch
·Fan motor
·Directional valve
SECTION 4 BRAKE AND FAN SYSTEM SECTION 4 BRAKE AND FAN SYSTEM
4-1