O-Rings with Backup Rings for Hydraulic Cylinders
Core Function & Design
O-rings are circular, donut-shaped gaskets engineered to create a leak-proof seal between two mating surfaces (e.g., pipe flanges, hydraulic cylinders, pump housings). Their toroidal geometry enables:
Radial compression: Deforms under pressure to fill gaps.
360° sealing surface: Ensures uniform pressure distribution
O-rings are circular elastomeric seals designed to prevent fluid/gas leakage in static and dynamic applications. Their simple toroidal shape allows 360° sealing through controlled compression (typically 15-30%) within a gland.
Key Attributes:
Materials: Nitrile (NBR) for oil/fuel resistance, Viton® (FKM) for high temps/chemicals, EPDM for weather/steam.
Function: Block leaks while accommodating minor shaft misalignment/vibration.
Applications: Hydraulic systems, fuel injectors, pipe fittings, and aerospace components.
Critical Factors:
Groove Design: Must match O-ring cross-section to avoid over-compression (causing extrusion) or under-compression (leak paths).
Surface Finish: Shaft/gland surfaces require ≤1.6µm roughness (Ra) to prevent wear.
Failure Modes: Chemical degradation, compression set, or installation damage (nicking).
Best Practices:
Use lubrication (silicone grease) during installation.
Avoid twisting; inspect for pre-existing flaws.
Select hardness (e.g., 70-90 Shore A) based on pressure (softer for low-pressure static seals)
