Sealing principle: how does a TCN oil seal work?
The pressure resistance of a TCN oil seal does not rely on extra components, but on the geometry of the sealing lip. This design is commonly described as a pressure-loadable sealing lip, because the lip geometry is intended to remain stable under internal pressure.
The short primary lip, supported by a garter spring, keeps the contact line between the lip and shaft controlled and reproducible. The spring provides a constant base load on the lip, while the short lip length limits deformation caused by pressure and temperature. This makes the TCN pressure oil seal suitable for viscous and low-viscosity media, and in specific cases even gaseous media, provided that rotational speed and heat generation remain within permissible limits.
The fully elastomer-coated outer diameter provides static sealing in the housing and helps prevent fretting corrosion between the seal and housing. This is especially relevant in aluminum housings, split housings and refurbished hydraulic pumps or motors.
TCN vs TC oil seal
TC and TCN oil seals are often compared because both are rotary shaft seals with a double-lip design. The main difference is the operating condition they are built for. A standard TC oil seal is used for common rotary shaft sealing in pressure-free or splash-lubricated environments. A TCN pressure oil seal is selected when the application involves internal pressure and a pressure-resistant sealing lip is required.
| Oil seal type |
Choose this type when... |
| TC oil seal |
You need a standard rotary shaft oil seal for pressure-free or splash-lubricated applications. |
| TCN pressure oil seal |
You need a pressure-resistant rotary shaft seal for applications with internal pressure. |
| TC Plus oil seal |
You need the specific TC Plus profile or execution. |
| DC oil seal |
You need the specific DC profile or another related rotary shaft seal execution. |
When to choose a TCN pressure oil seal
Choose a TCN pressure oil seal when the original seal specification calls for a TCN profile or when the shaft seal is exposed to internal pressure. This is common in hydraulic pumps, hydraulic motors, gear pumps, vane pumps, orbit motors, compact hydraulic units, power packs and mobile machinery.
The TCN profile is also useful in industrial drives and transmissions where local pressure build-up can occur due to limited venting, temperature increase or low-viscosity lubricants. In these conditions, the stable lip design helps prevent oil or lubricant from being forced out along the shaft.
A TCN oil seal is not the right solution for every application. At high rotational speeds, the permissible pressure decreases. If both pressure and speed are high, another sealing concept such as a cassette seal or mechanical seal may be more suitable.
High pressure rotary shaft seal applications
TCN oil seals are used where a compact rotary shaft seal must handle more pressure than a standard TC oil seal. The pressure-loadable lip makes the TCN suitable for many hydraulic and industrial sealing applications, provided that shaft speed, pressure, temperature, lubrication and heat generation remain within acceptable limits.
Typical applications include:
- Hydraulic pumps
- Hydraulic motors
- Gear pumps
- Vane pumps
- Orbit motors
- Compact hydraulic units
- Power packs
- Mobile machinery
- Industrial drives and transmissions with local pressure build-up
- Aluminum or split housings in refurbished pumps and motors
TCN oil seal materials
The construction of a TCN pressure oil seal is important, but the material determines whether the seal is suitable for the medium, temperature and operating environment. NBR is commonly used for mineral oils, greases and general hydraulic applications. FKM/Viton is selected when higher temperatures or more demanding chemical conditions are involved.
Other materials such as HNBR, ACM, CR, EPDM and silicone may be used when the application has specific media, temperature or mechanical requirements. The spring and reinforcing ring can also be supplied in stainless steel when corrosion resistance is required.
| Material |
Typical temperature range |
Key properties |
| NBR (Nitrile Rubber) |
-30 °C to +100 °C |
Good wear resistance, suitable for mineral oils and greases, cost-effective. Recommended maximum of 80 °C with synthetic oils. |
| FKM / Viton |
-20 °C to +180 °C |
Excellent heat resistance and chemical resistance. Suitable for synthetic oils and more demanding media. |
| HNBR |
-30 °C to +150 °C |
Improved mechanical strength, pressure resistance and wear resistance compared with NBR. |
| ACM |
-20 °C to +150 °C |
Good resistance to hot oils and oxidation, with moderate low-temperature performance. |
| CR |
-30 °C to +120 °C |
Balanced oil and weather resistance with moderate mechanical properties. |
| EPDM |
-40 °C to +150 °C |
Excellent resistance to water, steam and brake fluids. Not suitable for mineral oils. |
| Silicone |
-60 °C to +200 °C |
Very wide temperature range and good low-temperature flexibility, but limited wear resistance and pressure capability. |
Selecting the right TCN oil seal size
Selecting the right TCN oil seal starts with the shaft diameter, housing bore and seal width. The operating conditions are just as important. Pressure, rotational speed, temperature, medium, lubrication and heat dissipation all influence whether a TCN pressure oil seal is the correct choice.
For reliable sealing, the shaft must comply with the correct tolerances, have a torsion-free surface and sufficient hardness. The housing must also be suitable for static sealing. A lead-free shaft surface and correct housing finish help the TCN seal maintain stable contact with the shaft and reliable sealing in the housing.
Use the product filters above to find the correct TCN oil seal by inside diameter, outside diameter, width and material. If the required size or material is not listed, contact us to check availability or a suitable alternative.
Pressure and speed limits
A TCN pressure oil seal can handle several bar of pressure at low rotational speeds, but pressure capacity decreases as speed increases. This is why the right seal choice depends on the combination of shaft diameter, rotational speed and pressure, not on one value alone.
| Rotational speed |
Shaft Ø 20 mm |
Shaft Ø 40 mm |
Shaft Ø 80 mm |
| 0 rpm |
10.0 bar |
8.5 bar |
7.0 bar |
| 500 rpm |
10.0 bar |
8.5 bar |
5.0 bar |
| 1000 rpm |
5.5 bar |
4.5 bar |
3.0 bar |
| 2000 rpm |
3.0 bar |
2.5 bar |
1.5 bar |
| 3000 rpm |
2.0 bar |
1.5 bar |
0.3 bar |
| 4000 rpm |
1.2 bar |
0.5 bar |
0.0 bar |
| 5000 rpm |
0.7 bar |
0.0 bar |
- |
| 6000 rpm |
0.0 bar |
- |
- |
TCN oil seal references and equivalents
When replacing or specifying a TCN pressure oil seal, different manufacturers may use different references for comparable high pressure rotary shaft seals. These references are useful when you need to match an existing seal, convert a manufacturer code or find a TCN equivalent for a pressure-loadable oil seal design.
Common TCN oil seal references include WASY, OS-N11, TR-U, RST-D, GAP, BAB SL, 827 SK, DGSP, BABSL, CF, TCV / TCN and KAS-P. Always check the shaft diameter, housing bore, seal width, material and operating conditions before selecting a replacement seal.
| Manufacturer / supplier |
Reference for comparable high pressure oil seal |
| Dichtomatik |
WASY |
| Anyseals |
OS-N11 |
| B+S |
TR-U |
| Eriks |
RST-D |
| FP Paris |
GAP |
| FST |
BAB SL |
| Goetze |
827 SK |
| Kaco |
DGSP |
| Kramp |
BABSL |
| Stefa |
CF |
| Taiwan / NOK |
TCV / TCN |
| Vota |
BAB SL |
| Kimman |
KAS-P |
Comparable oil seal types
A TCN pressure oil seal is often compared with standard TC, TC Plus, DC and TB oil seals. Comparing these types helps prevent choosing a standard rotary shaft seal for an application where pressure resistance is actually required.
| Related type |
Why compare it with TCN? |
| TC oil seal |
Relevant when a standard rotary shaft oil seal is sufficient for pressure-free or splash-lubricated conditions. |
| TC Plus oil seal |
Relevant when comparing specific TC-style executions. |
| DC oil seal |
Relevant when comparing another oil seal profile for rotary shaft applications. |
| TB oil seal |
Relevant when comparing metal outer diameter oil seals with elastomer-coated TCN seals. |
| All oil seals |
Useful when comparing all available oil seal profiles in one overview. |
Need help choosing a TCN pressure oil seal?
If you are not sure which TCN oil seal size, material or pressure rating you need, our specialists can help you compare the options. Share the shaft diameter, housing bore, seal width, medium, temperature, pressure and rotational speed, and we will help you check the most suitable TCN pressure oil seal or alternative rotary shaft seal.
Contact us for TCN oil seal advice
