Review article

Multi-link working equipment of modern hydraulic transport-technological machines (TTM) is driven by double-acting hydraulic cylinders with one-way thrust rod, the operation of which goes on accompanied with a complicated plane-parallel movement of the cylinders in space. Functionally, each cylinder is exposed to the whole complex of operational longitudinal and transverse load. Currently, in most cases, the workability of hydraulic cylinders according to the parameters of their loading capacity is investigated on the basis of the assessment of longitudinal stability of the compressed rod of variable section. Herewith, depending on its flexibility, it is decided to apply either the Euler formula or the Yasinsky formula, where, unfortunately, the slope of the rod in space is not taken into account. However, during the operation, the hydraulic cylinder, obliquely situated in space, due to the longitudinally-transverse loading is deformed in a vertical longitudinal plane with emergence of entire deflection. In this case, the limit value of the longitudinal compressing force is less than the limiting compressing force of the stable rod. This means that the rod with an initial deflection is more prone to bending and the possibility of residual plastic deformation emerging in the sections of its elements than the straightforward located, vertically positioned rod, and consequently, it has less reliability. Hence, it may be concluded, that an evidence-based description of the areas of the hydraulic cylinder operation in condition of longitudinal-transverse bending or stability, as well as the border separating these conditions, is an urgent task.