Products
Rotary seals and rotary shaft seals
A rotary seal closes the gap where a turning shaft leaves a housing. Most are rotary lip seals, also called rotary shaft seals or oil seals: a flexible lip, held on the shaft by a garter spring, that keeps lubricant in and dirt out but is not a pressure seal. Where the duty adds pressure, heavy dirt or a worn shaft, a pressure-rated lip, a cassette seal or a seal built to the drawing takes over. Conquest Seal supplies radial shaft seals, also sold as rotary shaft seals, rotary lip seals and oil seals, in inch and metric sizes. Send the part number or drawing and we quote it.
- Also called
- Rotary shaft seal, rotary lip seal, radial shaft seal, oil seal
- Families
- Radial lip; axial and V-ring; PTFE and composite; non-contacting
- Standard lip pressure
- 0.3 bar (4.4 psi), rated by NOK® for its standard types; Freudenberg gives 0.2 to 0.5 bar (2.9 to 7.3 psi) for its standard lips; a lubricant retainer, not a pressure seal
- Speed rating
- Surface speed at the lip, rated by each maker for its own design
- Designations
- Letter codes (SC, TC, TB), ISO 6194-1 types, DIN 3760 forms, JIS B 2402, JASO
- To quote
- Shaft, bore and width; speed; pressure; temperature; media
Sources: NOK Oil Seals catalogue 014E, read 2026-09-16; Freudenberg Technical Manual for Simmerring® seals and rotary seals, read 2026-09-16.
What a rotary seal does
A rotary seal sits where a shaft turns inside a fixed housing: the output shaft of a gearbox, the drive end of a pump, a motor spindle, an axle wheel end. The lip rides on a thin film of the lubricant it is holding in. Take that film away and friction heats the lip until it hardens and cracks; add pressure it was not built for, or run it on a rough or grooved shaft, and it leaks.
Rotary seal, rotary shaft seal, rotary lip seal: one part, several names
Rotary shaft seal, rotary lip seal, radial shaft seal and oil seal usually mean the same part: a spring-loaded elastomer lip in a metal or rubber-covered case. Radial says the lip presses inward on the shaft diameter, where an axial seal such as a V-ring runs against a face. In hydraulics, rotary seal can also mean a pressure seal for a swivel or rotary joint, which is a different design for a different duty and is covered further down this page.
Rotary seal types
Each type below is a construction, not a brand. The letter codes are the ones printed on most seal boxes; the full mapping to ISO, DIN, JIS and JASO is on the cross-reference page. Select a type for when to use it, when to use another, and what goes wrong.
| Seal type | Designation | Family | Duty |
|---|---|---|---|
| Single lip, rubber-covered outside diameter | SC | Radial lip seals | Retaining oil or grease where the outboard side is clean |
| Single lip, metal outside diameter | SB | Radial lip seals | Retaining oil or grease where the outboard side is clean and the seat must be exact |
| Sealing lip and dust lip, rubber-covered outside diameter | TC | Radial lip seals | Retaining oil or grease with fine dust on the outboard side |
| Sealing lip and dust lip, metal outside diameter | TB | Radial lip seals | Retaining oil or grease with fine dust outboard, in a bore that must locate the seal exactly |
| Fabric dust lip, rubber-covered outside diameter | TCK | Radial lip seals | Coarse dirt and sand, where a rubber dust lip packs and drags |
| Pressure-resistant lip, stiffened | TCV | Radial lip seals | Rotating shafts at moderate pressure, on relatively small diameters |
| Pressure-resistant lip with an auxiliary cage | TCN, TCZ | Radial lip seals | Rotating shafts at higher pressure |
| Grease and dust seal, rubber outside diameter, no spring | VC, VB | Radial lip seals | Holding grease in or keeping dirt out. Not a pressure seal in any degree. |
| Grease seal with dust lip, rubber outside diameter | KC, KB | Radial lip seals | Holding grease in where there is some dust on the other side |
| Hydrodynamic (wave) lip | wave lip | Radial lip seals | Retaining thin oils, and reducing the heat a straight lip generates |
| V-ring axial seal | V-ring | Axial and V-ring seals | Excluding dirt and slinging liquid away from a primary seal or a bearing |
| PTFE lip in a metal case | PTFE lip seal | PTFE and composite rotary seals | Dry running, chemical service, and speeds a rubber lip cannot hold |
| Cassette seal | cassette seal | Non-contacting and unitized seals | Dirty, wet, heavy duty where the shaft cannot be relied on as a counterface |
| Unitized seal with an integral wear sleeve | unitized seal | Non-contacting and unitized seals | Worn, soft or unhardened shafts, and assemblies fitted as one part |
| Bearing isolator, non-contacting labyrinth | bearing isolator | Non-contacting and unitized seals | Long bearing life where a rubbing lip would wear out or cost too much torque |
| Shaft repair sleeve | shaft repair sleeve | Non-contacting and unitized seals | Restoring a grooved or damaged shaft without machining it |
Sources: NOK Oil Seals catalogue 014E, read 2026-09-16; Freudenberg Technical Manual for Simmerring seals and rotary seals, read 2026-09-16; SKF® Industrial Seals, Product Overview, read 2026-09-16; Parker® Rotary Seal Design Guide, Catalog EPS 5350/USA, read 2026-09-17.
Pressure and speed: what the makers rate
A standard lip seal is a lubricant retainer. NOK rates its standard oil seal types to 0.3 bar (4.4 psi), and Freudenberg's manual gives 0.2 to 0.5 bar (2.9 to 7.3 psi) for its standard lips. Above that the choice is a stiffened or supported lip, a purpose-built pressure design, or a seal made to the drawing.
Speed is rated as surface speed at the lip, not as rpm, and each maker rates its own design under its own conditions. There is no single speed limit for an oil seal. To compare a duty with the table, convert rpm to surface speed: shaft diameter (inch) x rpm x 0.262 = feet per minute, or in metric units, shaft diameter (mm) x rpm x 0.0000523 = meters per second.
| Design | Maker | Pressure | Surface speed | Conditions |
|---|---|---|---|---|
| Standard radial lip seal | NOK | 0.3 bar (4.4 psi) | no figure published | NOK's standard oil seal types; a standard lip is not a pressure seal |
| Freudenberg standard radial lip seal | Freudenberg | 0.2 to 0.5 bar (2.9 to 7.3 psi) | no figure published | Freudenberg's standard lips, the lower figure for two of its types; a standard lip is not a pressure seal |
| TCV, stiffened pressure lip | NOK | 3 bar (43.5 psi) | no figure published | A momentary surge peak, not a working pressure |
| TCN, lip with an auxiliary cage | NOK | 9.8 bar (142 psi) | no figure published | A momentary surge peak, not a working pressure |
| TCZ, caged lip, highest surge rating | NOK | 20 bar (290 psi) | no figure published | A momentary surge peak, not a working pressure |
| PTS pressure seal for poor lubrication | Freudenberg | 10 bar (145 psi) | 20 m/s (3,937 ft/min) | Pressure and speed are separate ceilings; the maker states they do not all occur together |
| BAHD high-pressure rotary seal | Freudenberg | 150 bar (2,176 psi) | 0.3 m/s (59 ft/min) | The speed is the rating at the design's pressure limit |
| HLPS high-low pressure seal | Freudenberg | 220 bar (3,191 psi) | 0.2 m/s (39 ft/min) | The speed is the rating at the design's pressure limit |
| Lip seal with a dust lip, in oil | Freudenberg | no figure published | 8 m/s (1,575 ft/min) | Dust lip, NBR or FKM, sealing an SAE 20 motor oil |
| HDS large-diameter seals | SKF | no figure published | 25 m/s (4,921 ft/min) | SKF's rating for its HDS designs; other rows of the same table differ |
Each figure is one maker's rating for one of its own designs, not a limit for the class. Where a cell reads no figure published, the maker gives none.
Sources: NOK Oil Seals catalogue 014E, read 2026-09-16; Freudenberg Technical Manual for Simmerring seals and rotary seals, read 2026-09-16; SKF Industrial Seals, Product Overview, read 2026-09-16; Parker Rotary Seal Design Guide, Catalog EPS 5350/USA, section 2, read 2026-09-17.
Heavy-duty and pressure-rated rotary seals are chosen on pressure, surface speed and shaft condition together, so the quote starts from all three. Send the part number or drawing and we quote it.
Cross-reference by maker designation
The same seal carries a different name in each scheme. A TC seal in the letter codes is Type 4 with lip in ISO 6194-1, TYPE 4 in JIS B 2402 and D in JASO. Matched by construction against the DIN form definitions, it is form AS. Three traps catch buyers: ISO numbers its types where DIN letters its forms; SKF uses the letter A for a contacting auxiliary lip, close to the opposite of the industry sense; and the grease and dust types have no ISO or JIS equivalent at all.
Makers also name their own designs. NOK adds a suffix for a variant, as in TCV, TCN and TCZ for its pressure-resistant lips; Freudenberg names its pressure designs, such as BAHD and HLPS; SKF names families such as HDS and HDL. Send the designation exactly as the seal or the parts list prints it, with the three dimensions.
Sources: NOK Oil Seals catalogue 014E, page 8, read 2026-09-16; Freudenberg Technical Manual for Simmerring seals and rotary seals, read 2026-09-16; SKF Industrial Seals, Product Overview, read 2026-09-16.
Swivel seals and rotary joints: quoted to the drawing
A swivel, also called a rotary joint or rotary union, carries fluid from a fixed part of a machine to a turning one, so its seals hold system pressure while the joint rotates or oscillates. That is outside what a standard lip seal is rated for, and the seal is set by the swivel maker's design rather than by a catalog size, so the quote works from the drawing.
Send, with the drawing or the seal part number:
- The swivel maker's drawing, or the seal or seal kit part number
- Groove diameters and groove widths for each seal position
- Pressure: normal working pressure and any peaks
- Motion: continuous speed in rpm, or the oscillation angle and cycle rate
- Fluid by name, and the temperature at the seal
- The quantity
Send the part number or drawing and we quote it.
Sources: Parker Fluid Power Seal Design Guide, Catalog EPS 5370/USA, 2007, 2008, Appendix A, read 2026-09-25.
Sizing inputs: what to send for a rotary seal quote
The three dimensions identify the size. The duty decides the lip, the case and the material, so send it with the dimensions.
- Shaft diameter where the lip runs, and the housing bore diameter, in inches or millimeters
- Seal width, or the bore depth available
- Shaft speed in rpm, and whether the shaft turns both ways (a hydrodynamic lip can be directional)
- Pressure across the seal, or none if the housing is vented
- Temperature at the seal, not only in the sump: lowest, normal running and highest
- The fluid inside by name, and what is outside: dust, mud, water or wash-down
- Shaft condition: hardness, finish, and any groove worn by the old seal
- Runout or misalignment, if it has been measured
- What is printed on the old seal (letter code, maker designation, dimensions), the equipment make and model, and the quantity
The shaft counterface the makers ask for: plunge ground to 10 to 17 µin Ra (0.25 to 0.43 µm Ra), at least Rockwell C30 (Rockwell C45 where there are abrasives or a high-pressure design), and no machining lead. The finish band is where the ranges Parker and Timken® publish overlap.
Send the list with any drawing through the request-a-quote form, and a Conquest representative replies with the quote.
Sources: Parker Fluid Power Seal Design Guide, Catalog EPS 5370/USA, 2007, 2008, Appendix A, read 2026-09-25; Parker Rotary Seal Design Guide, Catalog EPS 5350/USA, section 2, read 2026-09-17; Timken, Recommendations for Bearing Seals, The Timken Company, read 2026-09-17.
What Conquest quotes, by seal type
Conquest Seal supplies radial shaft seals, also sold as rotary shaft seals, rotary lip seals and oil seals, in inch and metric sizes. Send the part number or drawing and we quote it.
For cassette, combi and unitized seals; axial seals and V-rings; shaft repair sleeves; end caps; heavy-duty and pressure-rated rotary seals; and swivel seals, send the part number or drawing and we quote it.
Standards that name rotary shaft seals
A standard fixes dimensions and tolerances, not the material or the duty. Where the revision could not be confirmed from the issuing body, the standard is named without one.
ISO 6194-1:2007
Rotary shaft lip-type seals incorporating elastomeric sealing elements, Part 1: Nominal dimensions and tolerances. This is the international dimensional standard a metric shaft seal is built to. If a seal is described as ISO 6194, the three dimensions and their tolerances are defined, not the material and not the duty.
DIN 3760
Radial shaft seals. The form letters most European catalogs use come from here. A part described as DIN 3760 form A has a rubber-covered outside diameter, which is what lets it seal in a split housing or a light alloy bore.
DIN 3761
Rotary shaft lip type seals for automobiles. Named alongside DIN 3760 in maker literature. Which of the two standards owns which form is not settled in the maker documents cited here.
JIS B 2402
Rotary shaft lip type seals. A seal specified from a Japanese drawing will carry a JIS type number rather than an industry letter code. The cross-reference page maps them.
ASTM D2000
Standard Classification System for Rubber Products in Automotive Applications. A maker states a lip compound as a line call-out such as M2 BG 710 or M2 HK 810. That call-out is how a compound is specified on a drawing without naming a brand. Where a maker prints one, this site repeats it exactly as printed.
Sources: NOK Oil Seals catalogue 014E, read 2026-09-16; Freudenberg Technical Manual for Simmerring seals and rotary seals, read 2026-09-16; SKF Industrial Seals, Product Overview, read 2026-09-16.
When a rotary seal leaks
A rotary shaft seal rarely fails on its own; the shaft, the bore, the lubricant, the temperature or the fitting put it outside what the lip can follow. The troubleshooting page works from what you can see on the removed seal and the shaft.
NOK is a trademark of NOK Corporation; SKF is a trademark of Aktiebolaget SKF; Simmerring is a trademark of Carl Freudenberg KG; Parker is a trademark of Parker Intangibles LLC; Timken is a trademark of The Timken Company. The maker designations on this page are the makers' own. No affiliation or endorsement is implied.
Industries that buy rotary seals
Frequently asked
Is a rotary seal the same as a rotary shaft seal?
Usually. Most buyers who say rotary seal mean a rotary shaft seal, also called a rotary lip seal or oil seal: a spring-loaded lip that runs on a turning shaft and keeps lubricant in. In hydraulics the term can also mean a pressure seal for a swivel or rotary joint, which is a different design, so say which one the equipment uses.
Can a rotary lip seal hold pressure?
A standard one holds very little. NOK rates its standard oil seal types to 0.3 bar (4.4 psi), and Freudenberg's manual gives 0.2 to 0.5 bar (2.9 to 7.3 psi) for its standard lips. Pressure-rated designs go further: NOK rates its stiffened TCV lip to 3 bar (43.5 psi) and its caged TCN lip to 9.8 bar (142 psi), both as momentary surge peaks.
How is the speed limit of a rotary shaft seal stated?
As surface speed at the lip, because the same rpm is a different rubbing speed on a small shaft and a large one. The conversion is shaft diameter (inch) x rpm x 0.262 = feet per minute. Each maker rates its own design under its own conditions, so compare the duty with that maker's figure for that design rather than with a general limit.
What do I need to send to get a rotary seal quoted?
The shaft diameter, the bore diameter and the width, or the markings on the old seal, plus the shaft speed, any pressure, the temperature at the seal and the fluid. A drawing or the equipment part number replaces most of that. A Conquest representative replies with the quote.
Related pages
Orders are handled under Conquest Seal's AS9100D quality management system, whose certificate scope includes distribution.
Send the shaft, bore and width, or the drawing
The three dimensions or the old seal's markings, the speed, any pressure, the fluid and the quantity. A Conquest representative replies with the quote.
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