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| Illustration 1 | g03671219 |
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Rear suspension cylinder operation (1) Cylinder | |
The rear suspension cylinders are fastened between supports on the rear of the machine frame and to the rear axle housing. The suspension cylinder is an oil-pneumatic hydraulic cylinder. The rear suspension cylinders are located in line with the side rails of the frame. The rear suspension cylinders provide the shock absorber action between the rear wheels and the machine frame. The rear suspension cylinders support the rear end of the machine which includes the load.
The main components of the suspension cylinder are a cylinder and a rod. The rod is fastened to the rear axle housing with a pin. The cylinder is fastened to the rear of the frame with a pin. As the wheel moves up or as the wheel moves down, the rod is free to move inside the cylinder. The rear axle housing moves with the wheel. The rod moves with the rear axle housing.
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| Illustration 2 | g01973113 |
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Rear suspension cylinder operation (1) Cylinder (2) Nitrogen chamber (3) Rod (4) Orifice (5) Drain ball check (6) Cavity (7) Oil Chamber (AA) Nitrogen (LL) Oil | |
The orifices (4) and the drain ball check (5) control the flow rate of the oil from oil chamber (7) to cavity (6).
When a shock load is felt in the rear wheels, the rear axle housing will move up. This movement causes rod (3) to move up in cylinder (1). The movement of rod (3) compresses the nitrogen in nitrogen chamber (2). Oil flows from oil chamber (7) to cavity (6) through orifice (4) and through drain ball check (5).
The compression of the nitrogen in nitrogen chamber (2) provides the shock absorber action. The suspension cylinder dampens the amount of shock load that is felt by the machine frame.
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| Illustration 3 | g01973336 |
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Rear suspension cylinder operation (1) Cylinder (2) Nitrogen chamber (3) Rod (4) Orifice (5) Drain ball check (6) Cavity (7) Oil Chamber (AA) Nitrogen (LL) Oil | |
As the shock load diminishes, the action of the suspension cylinder is reversed. The weight of the wheel, the rear axle housing, and the pressure of the nitrogen in nitrogen chamber (2) moves rod (3) out of cylinder (1). As rod (3) moves down, the oil volume of cavity (6) decreases and the oil is put under pressure. The flow of oil closes drain ball check (5). The oil pressure in cavity (6) holds drain ball check (5) closed. At this time, oil can only drain to oil chamber (7) through orifice (4).
As rod (3) moves down, the lower orifice is closed and the amount of oil that goes to oil chamber (7) is stopped. By slowly decreasing the amount of oil that drains to oil chamber (7), the suspension cylinder reduces the speed of downward movement for rod (3). This reduces the shock load that is created when rod (3) reaches the bottom of cylinder (1).