

Rod seals, double-acting, Type SD 02– SD 03
Double-acting rod seals of the types SD 02 (without notches) and SD 03 (with notches) are ideally suited for use in hydraulic systems and promise stick-slip-free running as well as good dry-running properties. The media used in these applications range from mineral oil-based hydraulic liquids, environment-friendly bio-oils and water to flame-resistant hydraulic liquids and air.
While the PTFE profile ring seals dynamically against the cylinder surface, the elastic O-ring ensures uniform contact pressure of the PTFE profile ring onto the cylinder surface and at the same time for a static sealing between profile ring and groove base.
Even with low pressures, the piston seal shows good sealing effect due to the inherent preloading of the PTFE profile ring and the contact force of the preloaded O-ring. At higher system pressures, the medium pressurizes the O-ring causing it to press the PTFE seal with enhanced force against the cylinder surface.
With different material combinations, the piston seal can be used reliably across the whole pressure, speed and temperature range.
Notches
To ensure that the preload on the seal is maintained under sudden changes in pressure and in direction of motion, it can be provided with two radial notches on both sides (Typ SD 03).
Application media
- Mineral oil-based hydraulic liquids
- Water
- Air
- Environment-friendly bio-oils
- Flame-resistant hydraulic liquids
- Other media, depending on the O-ring material
Application range
Pressure: up to 40 Mpa (400 bar)
Speed: approx. up to 15m/s
Temperature: -30°C to +200 °C (depending on the O-ring material)
Surface finish
Roughness depth | Ra | Rt |
Running surface | ≤ 0,3 µm | ≤ 3,0 µm |
Groove base | ≤ 1,6 µm | ≤ 16,0 µm |
Groove flank | ≤ 1,6 µm | ≤ 16,0 µm |
Installation dimensions
Rods ø D | Gap size S | ||||||||
---|---|---|---|---|---|---|---|---|---|
Heavy Design | Standard Design | Light Design | Groove base ø D | Groove width L +0,2 | Radius R | 10 Mpa max. | 20 Mpa max. | 40 Mpa max. | O-ring line ø |
– | – | 8,0 – 18,9 | ø d + 4,9 | 2,2 | 0,4 | 0,3 | 0,2 | 0,15 | 1,78 |
– | 8,0 – 18,9 | 19,0 – 37,9 | ø d + 7,3 | 3,2 | 0,6 | 0,4 | 0,25 | 0,15 | 2,62 |
8,0 – 18,9 | 19,0 – 37,9 | 38,0 – 199,9 | ø d + 10,7 | 4,2 | 1,0 | 0,4 | 0,25 | 0,2 | 3,53 |
19,0 – 37,9 | 38,0 – 199,9 | 200,0 – 255,9 | ø d + 15,1 | 6,3 | 1,3 | 0,5 | 0,3 | 0,2 | 5,33 |
38,0 – 199,9 | 200,0 – 255,9 | 256,0 – 649,9 | ø d + 20,5 | 8,1 | 1,8 | 0,6 | 0,35 | 0,25 | 7,0 |
200,0 – 255,9 | 256,0 – 649,9 | 650,0 – 900,0 | ø d + 24,0 | 8,1 | 1,8 | 0,6 | 0,35 | 0,25 | 7,0 |
256,0 – 649,9 | 650,0 – 900,0 | – | ø d + 27,3 | 9,5 | 2,5 | 0,7 | 0,5 | 0,3 | 8,4 |
PTFE profile ring material
PTFE + bronze
The standard for hydraulic applications, good gliding behavior, particularly pressure and abrasion resistant, cannot be used in aqueous solutions or acids
PTFE + Glass-MoS2
particularly good resistance to wear and abrasion, application is possible even with poor lubricating pressure fluids, in water and in water-oil emulsions
PTFE + carbon
Exceptional resistance to abrasion and extrusion, can be used in water-hydraulics
For other possible materials see our overview of PTFE materials in the technical information section.
O-ring material
Nitrile rubber NBR: Temperature range − 30 °C to + 120 °C
Fluororubber FPM: Temperature range − 25 °C to + 200 °C
Overview of materials for dynamic seals
The following overview is a selection of typical PTFE materials used for seals, guide elements and wipers. Further PTFE materials are available for special applications.
Product data sheet (PDF)
Our data sheet for the Rod seals, double-acting, Type SD 02– SD 03 can be found here.
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