SKF
Hydraulic Seals
SKF hydraulic seals are precision sealing components designed for the demanding operating conditions of hydraulic cylinders and fluid power systems. This product category encompasses piston seals (maintaining pressure between the piston and cylinder bore), rod seals (controlling fluid film on the extending rod), wiper seals (excluding external contamination from the rod surface), guide rings (bearing elements that support side loads), and static seals (sealing between non-moving components). Hydraulic seals must withstand extreme pressures — typically 250 to 400 bar, with some applications exceeding 700 bar — while operating at temperatures from -40°C to +200°C, at sliding speeds up to 15 meters per second, and in contact with a wide range of hydraulic fluids including mineral oils, water-glycols, phosphate esters, and biodegradable fluids. For hydraulic cylinder manufacturers, mobile equipment OEMs, and maintenance teams servicing construction, agricultural, and industrial hydraulic systems, SKF hydraulic seals provide the reliable, long-lasting sealing performance essential for hydraulic system efficiency and safety.
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Trusted by Industry Leaders
Complete Fluid Power Sealing Portfolio
Source piston seals, rod seals, wiper seals, guide rings, and static seals from a single supplier with full material and dimensional compatibility across the entire cylinder sealing system.
High-Performance Thermoplastic Polyurethane Materials
SKF polyurethane seals offer exceptional wear resistance, excellent extrusion resistance at high pressures, and hydrolysis resistance for applications involving water-glycol fluids.
PTFE-Based Seal Solutions for Extreme Conditions
For high-temperature or chemically aggressive applications, PTFE seals with energizing elements provide reliable performance where polyurethane and rubber compounds degrade.
Step-Cut Piston Seals for Simple Installation
Split seal designs that assemble easily onto one-piece pistons while providing reliable bi-directional sealing at pressures up to 400 bar.
Integrated Guide Ring & Seal Systems
Reduce cylinder complexity by combining bearing support and sealing functions in optimized component designs that minimize overall piston length and weight.
Application Engineering Support for Cylinder Design
SKF engineers assist with seal groove design, material selection, and performance prediction to optimize cylinder reliability and service life at the design stage.
The Hydraulic Cylinder Sealing System: An Integrated Approach
Hydraulic cylinder reliability depends on the coordinated performance of multiple seal types working together as a system. The primary piston seal maintains the pressure differential that generates cylinder force — leakage across the piston seal directly reduces cylinder efficiency and slows operation. The rod seal controls the lubricating oil film on the extending rod surface, retaining sufficient fluid within the cylinder while preventing external leakage that creates safety hazards and environmental contamination. The wiper (scraper) seal is the first line of defense, removing dirt, ice, mud, and other contamination from the rod surface before it can damage the rod seal or enter the hydraulic system. Guide rings (wear rings) support radial loads and prevent metal-to-metal contact between the piston and cylinder bore or rod and head. When any single element of this sealing system is incorrectly specified or underperforms, the entire cylinder's reliability is compromised.
Hydraulic Seal Material Selection: Polyurethane, PTFE, and NBR
Selecting the correct hydraulic seal material requires matching the material properties to the application's temperature range, pressure, sliding speed, and fluid compatibility. Thermoplastic polyurethane (TPU) is the most widely used hydraulic seal material, offering an excellent balance of wear resistance, extrusion resistance, and flexibility with good performance in mineral oil-based hydraulic fluids. PTFE (polytetrafluoroethylene) seals excel in high-temperature applications (up to 200°C continuous), provide the lowest friction, and offer universal chemical compatibility — essential when aggressive fire-resistant fluids are specified. Nitrile rubber (NBR) remains economical for lower-performance applications but has limited temperature range and chemical resistance compared to polyurethane and PTFE. SKF offers all three material families with application-specific formulations optimized for hydraulic sealing performance.