SKF Nitrile Rubber (NBR) Seal, 40 mm ID, 50 mm OD, 12.5 mm

This seal is a compact, double-acting hydraulic sealing assembly designed to provide primary fluid retention and piston guidance in medium-duty cylinders. It incorporates a nitrile rubber sealing element together with integrated guide rings and anti-extrusion rings to reduce extrusion risk at elevated pressures while eliminating the need for separate piston guides.

• Nitrile primary element offers effective oil sealing and abrasion resistance
• Integrated anti-extrusion rings improve high-pressure performance up to 250 bar
• Split guide rings enable straightforward installation in confined bores
• Dual-acting design provides sealing on both piston faces for bidirectional use
• Compatible with cylinder speeds to 1 m/s to support dynamic applications

• Suitable for pneumatic-to-hydraulic conversion cylinders in automation systems
• Ideal for hydraulic actuators in electrical switchgear assemblies
• Used with linear motion modules in electronic test rigs
• Can be used for repair of industrial hydraulic pistons in mechanical workshops

The guide rings are moulded from acetal (POM) for low friction and dimensional stability, while anti-extrusion elements use a polyester-based compound to resist gap extrusion under pressure.

The assembly functions over a broad range with upper operating temperatures around 110°C and minimum continuous use down to −20°C, noting reduced performance limits closer to the extremes.

Certain metric sizes are designed to match housings produced in line with ISO 6547, ensuring correct groove form and clearance when fitting into compliant cylinders.

The split design permits retrofitting into an assembled cylinder without piston removal by compressing the rings into the groove and locating them sequentially into the split joint.