Defects cylinders
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Terminology cylinders [see illustration]
Rams - Boom cylinders - Arm cylinders - bucket cylinders - blade cylinders - swing cylinders
Fault category
Equipment drift - creep - leakage - cylinder rebuild - cylinder diagnostics - power loss - loss of speed.
Hydraulic cylinders are primarily used to convert fluid pressure and flow into a linear mechanical action.
For the hydraulic excavator they form the main function of moving the boom - arm & bucket in a semi
rotating motion. The cylinders rely on seals within the cylinders, failure will result in loss of digging force
and ultimately inoperative equipment, often seal failure will result in the cylinder extending and not retracting.
The speed of the cylinder is relative to the flow of fluid whilst the force of the cylinder is that of the
pressure applied, it is common practice that as the pressure’s raise so does the flow decrease, thus preventing engine overload and saving fuel.
A cylinder extending will have far greater force than when retracting as the area exposed to pressure is far
greater, the speed of a cylinder retracting will be far quicker than extending as the fluid demand for given
movement is considerably less than that of cylinder extension.
One other aspect of force is that of leverage, a long arm will sweep the ground much quicker than that of a shorter version however the actual force will significantly decrease with arm length, the force is also relative to the actual position of the geometry [see illustration]