Development of Powered Support Hydraulic Legs with Improved Performance

The paper gives a description of the technical solution for the design of a hydraulic leg piston for mechanized roof supports. This technical solution allows the sealing gap to remain almost constant in a wide range of pressures of the working fluid, while significantly improving the working conditions of the lip seal on the piston. This technical solution consists in the fact that, on the side of the piston cavity of the hydraulic leg, the piston contains a sleeve with a seal located on it, which under the action of the pressure of the working fluid deforms in the radial direction, compensating for an increase in the diameter of the working cylinder. In this case, the described technical solution is not subject to inertia and is able to work with static and with dynamic external loads on a hydraulic leg. The results of a comparative finite-element simulation of the stress-strain state of a hydraulic leg at the junction of the piston and the working cylinder are given for the 360 mm dia hydraulic leg of Glinik support with serial and proposed pistons. It is shown that with the proposed piston, when the pressure of the working fluid in the piston cavity is 62 MPa, the change in the radial sealing gap is less than 20 times compared with the serial design.