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| Illustration 1 | g06223557 |
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Hydraulic Accumulator (1) Accumulator (2) Charging valve (3) Chamber for nitrogen gas (4) Piston (5) Pressure oil chamber (6) Outlet to the retarder control valve and service brake control valve | |
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| Illustration 2 | g06223555 |
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Hydraulic Accumulator | |
Hydraulic accumulator (1) is on the right side of the front frame.
Hydraulic accumulator (1) has a sealed piston (4) that moves up and down inside the bore of the accumulator. Chamber (3) above the piston has a charge of nitrogen gas. The nitrogen gas is put into the accumulator through nitrogen charging valve (2).
Oil from the accumulator charging valve flows in through port (6). The oil then enters pressure oil chamber (5). This oil pushes piston (4) up which causes the nitrogen gas to compress. When the pressure in the accumulator reaches the cut-out pressure, the accumulator charging valve stops the flow of oil.
When the operator releases the brake pedal, the oil from chamber (5) flows out of port (6). The oil flows from port (6) through the retarder control valve and the service brake control valve to release the service brakes.
Pressing the service brake pedal vents oil from the wheel-end assemblies back to the hydraulic tank, allowing the springs to apply the brakes.
Hydraulic accumulator (1) also supplies pilot oil to the hoist control solenoid valves. The solenoid valves shift the spool in the hoist control, allowing high-pressure oil from the steering and braking piston pumps to operate the hoist cylinders.