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6.3 Cooling system
The system is a independent circuit. The pressure oil is going from the
accumulator charge valve the brake fluid box. Oil is passing through the power brake,
thus cooling recycle which can run to optimum brake ability.
The system is pan-hydraulic wetness braking (basic circuit showing). It
composes of pump、charge valve、globe valve、accumulator、working brake valve、
parking valve、pressure switch and tubes. The charge valve stops filling oil to braking
system when the oil pressure in the accumulator run to 15MPa, and at the moment it
fills oil to cooling circuit. When the oil pressure in the accumulator is lower 12.3MPa,
charge valve turns to filling to braking system anew.
The pressure oil from the pump pass through the charge valve,then filled to
accumulators which are in walking braking system and parking braking system. When
stepping on pedal, the high pressure oil which be stored in accumulators goes into
power braking, passing through brake valve, then make wheels stop running. When
the pedal is released, the braking is unlocked. The oil in the power brake goes through
brake valve and returns to oil tank. The oil pressure of the from the walking brake
valve is direct ratio with the force which be on the pedal. A very little power to make
the pressure run to 10MPa which walking brake system demands. The globe valve is
connect in both walking and parking brake circuit. This can assure one circuit
function when another is damaged.
Shortly after the engine start up, the low-pressure warning lamp is brightness for a
little time because of the oil pressure in the accumulator lower than warning(10MPa).
It turns off until the pressure higher than warning pressure. On this time the manual
braking valve can be released. If the vehicle is running, the system occur any kind of
trouble which result in the oil pressure in the accumulator lower than 10MPa, then the
low-pressure warning lamp is brightness. We must stop working and check brake
system on time.
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