O-ring, Y-ring, U-ring, and V-ring oil seals are core components of industrial fluid sealing systems, widely used in machinery manufacturing, automotive engineering, petrochemicals, and hydraulic transmission fields. Their performance directly impacts equipment operational efficiency and service life. Based on national and international standards (GB/T 3452, ISO 3601) and practical production scenarios, this brief outlines their key characteristics, application guidelines, and technical trends.
Sealing PrincipleReliance on synergistic effects of contact pressure and medium pressure to form a stable oil film or contact zone on the sealing surface, preventing fluid leakage and contaminant intrusion through material elastic deformation and structural self-sealing.
General Technical RequirementsPrimary materials include Nitrile Butadiene Rubber (NBR), Fluorocarbon Rubber (FKM), and Polyurethane (PU), adapting to operating temperatures of -40℃~200℃ and pressures of 0~100MPa.
O-Ring Oil Seal
Structural Feature: Circular cross-section, simple structure, easy installation, achieving sealing through compressive deformation.
Key Parameters: NBR variant suits -20℃~100℃ and ≤10MPa; FKM variant resists up to 200℃; standard compression rate ranges from 15% to 25%.
Advantage: Cost-effective and versatile for static or low-speed rotating applications.
Y-Ring Oil Seal
Structural Feature: Y-shaped lip design with pressure self-sealing function, lip oriented toward the pressure source.
Key Parameters: PU variant withstands ≤40MPa and linear speeds of 0.01~1m/s; FKM variant operates at -30℃~150℃; narrow structure handles up to 32MPa.
Advantage: Low friction resistance with automatic wear compensation, ideal for reciprocating motion.
U-Ring Oil Seal
Structural Feature: U-shaped open cross-section, relying on lip-to-surface fit for low to medium pressure conditions.
Key Parameters: Suitable for ≤15MPa and -20℃~120℃; universal for shaft and bore installations.
Advantage: Excellent followability and adaptability, requiring correct orientation toward pressure during installation.
V-Ring Oil Seal
Structural Feature: Multi-layer lip assembly (2~5 layers) with pressure rings and support rings, stackable for high-pressure use.
Key Parameters: Maximum pressure resistance of 100MPa; FKM variant operates at -40℃~200℃; compatible with linear speeds ≤5m/s.
Advantage: Superior high-pressure stability and extrusion resistance, designed for heavy machinery hydraulic systems.
Application-Based Selection
Low-pressure static sealing: O-ring oil seal (e.g., valve end caps, motor housings).
Reciprocating motion (hydraulic cylinders/piston rods): Y-ring oil seal, with PU material for high-speed conditions.
Low-speed reciprocating/rotating scenarios: U-ring oil seal (e.g., gearboxes, hydraulic motor end caps).
High-pressure heavy-duty applications (≥30MPa): V-ring oil seal (e.g., mining machinery, large hydraulic equipment).
Medium Compatibility
Mineral oil: NBR is preferred.
High-temperature/chemical media: FKM is recommended.
Wear resistance requirements: PU or fabric-reinforced structures.
Installation Specifications
Shaft surface roughness: Ra 0.2~0.63μm; hardness ≥HRC45.
Apply lubricant to lips before installation to avoid sharp edge scratches; ensure correct orientation of Y/V-ring lips toward pressure.
Maintain vertical force during press-fitting to prevent skeleton deformation; bore tolerance complies with H8 standard.
Maintenance Requirements
Regularly inspect lip wear and elastic degradation; replace immediately if leakage occurs.
Replacement cycle: 6~12 months for high-temperature conditions; 3~6 months for high-pressure applications.
Avoid medium contamination and incompatible fluid mixing.
Material InnovationApplication of nanomaterial-reinforced composites (graphene/carbon fiber) improves wear resistance by over 30%; eco-friendly biodegradable rubbers gradually replace traditional materials.
Structural OptimizationIntegrated lip designs reduce assembly errors; modular multi-layer combinations for V-ring seals adapt to customized working conditions.
Intelligent UpgradeSelf-sensing oil seals embedded with piezoelectric sensors enable real-time monitoring of lip pressure and wear status, supporting predictive maintenance.
