Professional O-Ring and Oil Seal Manufacturer, Sealing Solution Supplier Since 2008.
PU UR U-Cup Seal (Black Version) - High-Quality Hydraulic Cylinder Seal
Wear-Resistant Black Polyurethane Seal for Hydraulic Piston & Rod Reciprocation
- Superior wear resistance: Outlasts standard rubber seals, ideal for high-frequency motion; carbon black filler further boosts abrasion & tensile strength.
- Robust durability: Withstands pressure fluctuations, reduces replacement needs, and delivers excellent anti-aging & UV stability.
- Versatile fit: Compatible with both piston and rod applications, simplifying inventory; black finish resists dirt buildup for easy on-site maintenance identification.
This seal doesn’t just seal—it enhances system efficiency, cuts maintenance downtime, and lowers long-term costs. Trust it for consistent, reliable performance in demanding hydraulic environments, especially outdoor and heavy-load equipment.
5.0
design customization
Please fill out the form below to request a quote or to request more information about us. Please be sure to upload customized requirement documents or pictures, and we will get back to you as soon as possible with a response. we're ready to start working on your new project, contact us now to get started.
Please fill out the form below to request a quote or to request more information about us. please be as detailed as possible in your message, and we will get back to you as soon as possible with a response. we're ready to start working on your new project, contact us now to get started.
Product Advantages
Exceptional Wear Resistance
Crafted from carbon-black filled high-grade polyurethane, this black seal exhibits 3–5 times better wear resistance compared to standard nitrile rubber seals. Carbon black acts as a reinforcing filler to strengthen molecular structure, resisting friction caused by high-frequency reciprocating motions of pistons and rods, significantly extending the service life of the sealing system.
Superior Pressure Resistance
The material's excellent mechanical strength enables it to handle working pressures up to 50MPa. Even under high-pressure conditions, it is not easily squeezed into gaps, effectively preventing leakage. The carbon black reinforcement further improves extrusion resistance under heavy loads.
Strong Oil Resistance
It has good compatibility with various hydraulic oils such as mineral oil and synthetic oil, ensuring stable performance without swelling or hardening, thus maintaining reliable sealing.
Outstanding UV & Anti-Aging Performance
Different from the green standard version, this black UR U-cup contains UV stabilizer carbon black, absorbing over 99% ultraviolet radiation. It avoids aging, cracking and performance degradation under long-term outdoor sunlight exposure, perfectly suited for construction, agricultural and off-road machinery working outdoors.
Outstanding Elasticity and Recovery
The polyurethane material has excellent elasticity, allowing the U-shaped lip to tightly fit the sealing surface even with slight changes in the gap, ensuring a tight seal.
Long Service Life
Thanks to its reinforced wear resistance, pressure resistance, oil resistance and UV stability, the service life of this black seal is greatly extended, reducing the frequency of replacement and maintenance, and lowering the overall cost.
Working Principle
The PU UR U-cup seal relies on its unique U-shaped cross-sectional design to achieve sealing. When installed in the hydraulic cylinder, the U-shaped lip is in contact with the piston or rod surface. Under the action of hydraulic medium pressure, the lip expands outward, increasing the contact pressure with the sealing surface, thereby achieving a tight seal. This self-tightening effect ensures that the sealing performance is better as the pressure increases. During the reciprocating movement of the piston or rod, the lip can adapt to the movement, maintaining continuous contact with the sealing surface and preventing medium leakage. The carbon black enhanced body maintains stable elasticity even after long-term outdoor exposure.
Product Details
Material Quality
Adopts carbon black reinforced high-purity polyurethane raw materials with strict quality control to ensure stable material performance, free from impurities and bubbles. The added carbon black filler provides extra anti-UV and anti-oxidation capacity for harsh outdoor working scenarios.
Precision Manufacturing
Uses advanced molding technology, with precise control over the size of the cross-section (inner diameter, outer diameter, lip height) to ensure a perfect fit with the sealing groove. The dimensional tolerance is within ±0.05mm.
Lip Treatment
The lip is 经过 special polishing treatment, with a smooth surface and no burrs, reducing friction during movement and improving wear resistance.
Structural Design
The U-shaped structure is optimized, with reasonable thickness distribution of the lip and the bottom, ensuring both sealing performance and structural strength. Carbon black reinforcement enhances overall structural rigidity against heavy load deformation.
Surface Finish
The matte black surface of the seal is smooth and flat, which is conducive to the flow of hydraulic medium and reduces resistance; dark color hides oil stains and wear marks for easier field inspection.
Application Range
This black PU UR U-cup seal is widely used in various hydraulic systems that require reciprocating motion sealing, especially equipment working outdoors or under long-term UV exposure, including but not limited to:
- Construction machinery: Hydraulic cylinders of excavators, loaders, cranes, road rollers and other outdoor engineering vehicles
- Industrial equipment: Hydraulic systems of injection molding machines, die-casting machines, hydraulic presses, metallurgical hydraulic equipment
- Agricultural machinery: Hydraulic components of tractors, harvesters, agricultural loaders (long-term field outdoor use)
- Automobile industry: Hydraulic cylinders in automobile production lines and off-road vehicle hydraulic systems
- Metallurgical industry: Hydraulic equipment in steel mills and smelters
FAQ
Q: What is the temperature range applicable to this black seal?
A: The standard temperature range is -20℃ to +100℃. For special high-temperature or low-temperature environments, Forever Seals can provide customized products with a temperature range of -40℃ to +120℃. The carbon black formula does not narrow the temperature tolerance and adds outdoor anti-aging capability.
Q: Can this seal be used with water-based hydraulic fluids?
A: No, this seal is mainly designed for mineral oil and synthetic oil-based hydraulic fluids. For water-based hydraulic fluids, please choose Forever Seals' special seals for water-based media.
Q: How to determine the correct size when selecting?
A: You need to provide the inner diameter, outer diameter, and depth of the sealing groove, as well as the diameter of the piston or rod. Forever Seals' technical team will help you select the appropriate size. This black version shares identical dimensional specifications with our green PU UR U-Cup Seal, fully interchangeable if groove size matches.
Q: What is the service life of the black seal under normal working conditions?
A: Under normal indoor working conditions (appropriate pressure, temperature, and medium), the service life can reach 5000–10000 working hours. For outdoor UV-exposed environments, its service life is 2–3 times longer than the standard green PU model.
Q: Can this black seal be replaced with the green UR U-cup seal or other types of seals?
A: It depends on the specific sealing groove design. This black variant has fully consistent cross-section & dimensional specs with our green PU UR U-Cup Seal; if the groove size is compatible, they can be mutually replaced. For other U-cup styles, it is recommended to consult Forever Seals' technical staff for confirmation.
Enterprise Selling Points
Professional R & D Team
Forever Seals boasts a professional R & D team with many years of experience in seal design and material research. We developed this carbon black reinforced black PU formula specially for outdoor heavy machinery, continuously improve product performance and develop new products according to customer needs.
Strict Quality Control
From raw material procurement to production, testing, and packaging, Forever Seals implements strict quality control procedures. Each batch of black PU seals undergoes pressure testing, wear testing, UV aging testing and dimensional inspection to ensure qualified products leave the factory.
Customization Capability
Forever Seals can provide customized services according to customer's specific requirements (such as size, modified PU material, working environment, hardness adjustment, etc.) to meet the individual needs of different customers.
Efficient After-sales Service
Forever Seals has a professional after-sales service team to provide timely technical support and solutions for customer problems in the process of using products.
Advanced Production Equipment
Forever Seals adopts international advanced production equipment and production technology to ensure stable product quality and high production efficiency, and can meet the large demand of customers.
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