Study on the operational reliability of hydraulic support with clearances based on mechanical-hydraulic interaction

Hydraulic supports are core equipment in fully mechanized coal mining faces. However, unavoidable hinge joint clearances resulting from manufacturing tolerances can degrade bearing state and reduce operational reliability. This paper establishes a co-simulation model of the mechanical-hydraulic interaction to address the aforementioned issues. The simulation model’s reliability is experimentally validated. Based on this, the effects of variations in the hinge joint clearance parameter (position and value) on the support’s motion status, structural displacement, and posture angles are investigated. The results indicate that the clearance magnitude is the primary determinant of the column’s operating status. The intensity of pressure fluctuations within the cylinder chamber exhibits a strong positive correlation with the clearance size, achieving an average correlation coefficient of 0.98. Furthermore, hinge joint clearances significantly degrade motion accuracy and induce distinct directional posture trends: a clearance at hinge joint a results in a “nosing-down” trend of approximately 0.3°, whereas clearances at other positions induce a “nosing-up” trend of approximately 0.39°. Additionally, clearances at all locations lead to a reduction in the centroid displacement of structural components; notably, at a 5 mm clearance, the front link exhibits a maximum vertical displacement reduction of 17 mm. Finally, within the examined parameter range, the overall operational reliability of the hydraulic support remains controllable, with the kinematic reliability index η k maintained above 0.93 and the dynamic stability index η d exceeding 0.95. These findings provide quantitative insights into the operational status and reliability assessment of supports with hinge joint clearances.