994K Wheel Loader Machine Systems Caterpillar

Illustration 1	g03127138
(2) Accumulators

Illustration 2	g03124517
Brake accumulator (1) Nitrogen charging valve (2) Accumulator (3) Chamber (4) Piston (5) Pressure oil chamber (6) Outlet to the service brake control valve

Piston (4) moves up and down inside the bore of each accumulator (2). Chamber (3) has a charge of approximately 5516 kPa (800 psi)of dry nitrogen gas. Each accumulator is charged with nitrogen through charging valve (1).

Oil enters pressure oil chamber (5) from the brake pump. The oil reaches the pressure oil chamber through outlet port (6). The oil pushes piston (4) upward. The pressure of the oil compresses the nitrogen gas.

When the pressure in the accumulators reaches approximately 16000 ± 345 kPa (2320 ± 50 psi), the supply of oil is stopped. When either brake pedal is pushed, oil from pressure oil chamber (5) flows out of port (6) to the service brake control valve. This action will apply the service brakes.