Design and Buffering Performance Study of a 3D-Printed Labyrinth Buffer Sleeve for High-Speed Heavy-Load Hydraulic Cylinders

In the hydraulic hoist design for a water conservancy hub project in western China, the vertically positioned, high-speed, heavy-load hydraulic cylinder is required to achieve closing speeds of up to 16 m/min, which is 4–5 times faster than conventional hydraulic hoists. Traditional buffer structures in hydraulic cylinders are insufficient to meet these performance demands. To address this challenge, a labyrinth buffer sleeve with multi-stage labyrinth buffer channels was designed and manufactured using additive manufacturing technology. The feasibility and effectiveness of the labyrinth buffer sleeve were evaluated through numerical simulations and experimental testing. Results demonstrate that the sleeve offers superior flow capacity, speed control, and pressure reduction capabilities. The maximum flow velocity within the labyrinth flow field reaches 111.7–166.5 m/s at the narrowest section of the flow path. The pressure ranges from 9.95 MPa at the inlet to 0.5 MPa at the outlet. Upon entering the buffer stage, the cylinder’s velocity smoothly decreases from 8 to 9 m/min to 2 m/min. Compared to traditional spiral groove buffer sleeves, the 3D-printed labyrinth design enables staged buffering, reducing peak pressures by 80%, with peak values only 1/16 to 1/5 of those seen in conventional sleeves. This results in an 80% reduction in pressure impacts, eliminating the need for frequent on-site disassembly and reassembly for fit clearance adjustments.