Cylinder Under shock Load
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| Illustration 1 | g00998386 |
Suspension Cylinder (1) Port (O) (2) Port (N) (3) Rod (4) Cylinder (5) Orifices (6) Piston (7) Spring (8) Orifice (9) Sleeve (10) Stem (11) Ball (12) Orifice (13) Side port | |
The suspension cylinder is an oil-pneumatic hydraulic cylinder. The front suspension cylinders provide the shock absorber action between the front wheels and the machine frame.
When a shock load is felt in the front wheels, the front axle housing will move up. This movement causes cylinder (4) to move up around rod (3). The movement of cylinder (4) compresses the nitrogen in the cylinder. At the same time oil passes from the piston side of the cylinder through orifice (12) and into rod (3). Some of the oil flows through orifices (5) and past ball (11). This prevents voiding.
As piston (6) approaches the fully retracted position, orifice (12) is closed by stem (10). The flow of oil from the piston side of the cylinder to rod (3) is restricted to orifices (8). When piston (6) contacts sleeve (9) the sleeve moves along stem (10). This progressively covers orifices (8). This cushions rod (3) as the rod reaches the fully retracted position.
The compression of the nitrogen within the suspension cylinder provides the shock absorber action. The suspension cylinder dampens the amount of shock load that is felt by the machine frame.
Cylinder Under Normal Loads
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| Illustration 2 | g00998386 |
Suspension Cylinder (1) Port (O) (2) Port (N) (3) Rod (4) Cylinder (5) Orifices (6) Piston (7) Spring (8) Orifice (9) Sleeve (10) Stem (11) Ball (12) Orifice (13) Side port | |
As the shock load diminishes, the action of the suspension cylinder is reversed. The weight of the wheel and of the front axle housing in addition to the pressure of the nitrogen in the suspension cylinder moves cylinder (4) down rod (2) .
Oil flows through orifices (8) in stem (10) to the piston side of the suspension cylinder. As cylinder (4) moves down, the oil volume in the rod side of the suspension cylinder decreases and the oil is put under pressure. The flow of oil closes drain ball check (11). The oil pressure holds drain ball check (11) closed. At this time, oil can only drain to rod (3) through orifices (5) .
As cylinder (4) moves down, the lower orifice (5) is closed and the amount of oil that goes to rod side is decreased. The other orifice is slowly closed off as cylinder (4) moves down. This again decreases the amount of oil that goes to rod side. By slowly decreasing the amount of oil that drains to rod side, the suspension cylinder reduces the speed of downward movement for cylinder (4). This reduces the shock load that is created when cylinder (4) reaches the bottom of rod (3) .