Cookies on the SKF website

We use cookies to ensure that we give you the best experience on our websites and web applications. By continuing without changing your browser settings, we assume you give your consent to receive cookies. However, you can change your browser cookie setting at any time.

O-rings and back-up rings

O-rings are one of the most common sealing solutions. SKF supplies O-rings in a wide range of sizes and different materials, which make them appropriate for a wide variety of operating conditions and applications. They are easy to install and they enable a simple and cost-effective seal housing design.
O-rings maintain sealing contact force by radial or axial deformation in the seal housing between two machine components. The most important criteria that influence the maximum operating pressure at which O-rings in static radial sealing can be used are the following:
  • extrusion gap (fig. 1)
  • material (→ Materials)
  • sealed fluid
  • temperature
Under specific conditions, there is a risk for gap extrusion (→ Extrusion gaps and back-up rings). Back-up rings prevent O-rings from gap extrusion in static radial sealing (fig. 1).
O-rings are used in a wide variety of applications sealing various media. This section focuses on sealing systems for hydraulic cylinders. Therefore, this section and provided recommendations apply to static sealing of common mineral-based hydraulic fluids (→ Hydraulic fluids).
SKF logo