Professional O-Ring and Oil Seal Manufacturer, Sealing Solution Supplier Since 2008.
UN Series Hydraulic U-Cup Rod Seal
Product Overview
The UN series hydraulic seal is a single-acting rod seal widely used in standard hydraulic cylinders. Featuring a U-cup design, it fits securely into a rectangular groove and creates a tight, reliable seal against the piston rod. The UN series is manufactured from high-quality polyurethane (PU) with a Shore hardness of 92, offering an optimal balance of elasticity, wear resistance, and extrusion resistance for long service life in demanding hydraulic applications.
Key Features & Benefits
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High-Performance PU Material: Manufactured from premium polyurethane (PU 92 Shore A), offering excellent abrasion resistance, high tensile strength, and resilience against hydraulic fluids and oils.
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U-Cup Design: The asymmetric lip profile provides superior sealing performance and low friction, ensuring smooth rod movement and minimizing wear.
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Reliable Leakage Prevention: Effectively prevents internal fluid leakage, maintaining system pressure and efficiency.
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High Pressure Resistance: Capable of withstanding pressures up to 30 MPa, making it suitable for heavy-duty hydraulic applications.
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Wide Operating Temperature Range: Performs reliably across a broad temperature range, typically from -30°C to +105°C.
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Custom Sizes Available: Available in a wide range of standard and custom sizes to meet your specific application requirements.
Working Principle
The UN hydraulic seal operates on a pressure-activated sealing mechanism. As hydraulic pressure increases, the fluid forces the lips of the U-cup seal outward against both the piston rod and the housing groove. This creates a progressive sealing effect: the higher the system pressure, the tighter the seal. The seal's asymmetric lip profile ensures that the sealing lip maintains consistent contact with the rod surface throughout the stroke, effectively preventing fluid bypass while minimizing friction and wear. The seal is designed for single-acting applications, sealing effectively in one direction (typically rod sealing).
Product Specifications
| Specification | Detail |
|---|---|
| Series | UN Series |
| Type | Hydraulic U-Cup Rod Seal |
| Material | Polyurethane (PU) |
| Hardness | 92 Shore A |
| Working Pressure | Up to 30 MPa |
| Working Speed | 0.03 – 0.5 m/s |
| Temperature Range | -30°C to +105°C |
| Available Sizes | Wide range of standard and custom sizes available upon request |
Application Range
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Hydraulic Cylinders: Rod sealing in industrial, mobile, and agricultural hydraulic systems
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Construction Equipment: Excavators, loaders, bulldozers, and cranes
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Agricultural Machinery: Tractors, harvesters, and implements
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Industrial Machinery: Presses, injection molding machines, and hydraulic power units
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Pneumatic Systems: Suitable for pneumatic cylinder sealing applications
Custom Options
We offer custom sizes and specifications to meet your specific application requirements. Contact us with your dimensional requirements for a quick quotation.
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