TB/SB/TA/SA
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TB Oil Seal is a spring-loaded, double-lip rotary shaft seal featuring an exposed metal outer case. It is designed to retain lubricating oil or grease around rotating shafts while the secondary lip helps reduce the entry of dust and other external contaminants.
Compared with rubber-covered oil seals, the metal outer diameter provides a rigid press fit in accurately machined housing bores. This makes the TB structure suitable for many automotive, transmission, gearbox, motor and industrial machinery applications where dimensional stability and secure housing installation are important.
TBT supplies TB Oil Seal, SB Oil Seal, TA Oil Seal and SA Oil Seal in different sizes and sealing materials. Selection should be based on the required lip configuration, housing design, operating environment, lubricant and original seal structure.
A typical TB Oil Seal combines four important components:
● Main sealing lip – contacts the rotating shaft to retain lubricating oil or grease.
● Secondary dust lip – helps protect the primary sealing area against external dust and contaminants.
● Garter spring – maintains radial contact pressure between the primary sealing lip and shaft.
● Metal outer case – provides structural rigidity and creates a secure interference fit with the housing bore.
Unlike a TC Oil Seal with a rubber-covered outer diameter, the outer surface of a TB Oil Seal is primarily metal. The housing bore condition and dimensional accuracy therefore become particularly important during installation.
The TB structure is particularly useful when the application requires both a metal-case press fit and double-lip sealing.
A TB Oil Seal can be considered when:
● Lubricating oil or grease must be retained around a rotating shaft.
● External dust or light contamination also needs to be excluded.
● The housing is designed for a metal-to-metal press fit.
● High structural rigidity of the seal outer case is preferred.
● The housing bore has suitable dimensional accuracy and surface condition.
● The original equipment uses a TB-type metal case oil seal.
For replacement applications, it is generally better to match the original case and lip structure rather than selecting an oil seal only according to ID, OD and width.
The four structures mainly differ in two areas: the number of sealing lips and the construction of the metal outer case.
| Oil Seal Type | Lip Structure | Outer Case | Spring | Typical Selection |
|---|---|---|---|---|
| TB Oil Seal | Double lip | Metal OD | Yes | Oil retention + dust protection |
| SB Oil Seal | Single lip | Metal OD | Yes | Oil retention in relatively clean environments |
| TA Oil Seal | Double lip | Reinforced metal OD | Yes | Double-lip sealing with greater case rigidity |
| SA Oil Seal | Single lip | Reinforced metal OD | Yes | Single-lip sealing with reinforced case construction |
Both TB and SB Oil Seals use an exposed metal outer case and a spring-loaded primary sealing lip.
The main difference is the secondary lip.
A TB Oil Seal has a double-lip design, with the additional lip helping prevent dust and external contaminants from reaching the main sealing area.
An SB Oil Seal has a single sealing lip and is generally more suitable where the operating environment is relatively clean and the main requirement is lubricant retention.
Choose:
TB Oil Seal – when both oil retention and contamination exclusion are required.
SB Oil Seal – when the environment is cleaner and a secondary dust lip is unnecessary.
Both TB and TA Oil Seals normally use double-lip, spring-loaded structures.
The difference is mainly in the case construction.
The TB Oil Seal uses a conventional metal outer case, while the TA Oil Seal uses a reinforced metal case structure to provide greater structural support.
TA designs may therefore be preferred for larger seal sizes or applications where additional case rigidity is required.
When replacing an existing seal, do not substitute TB for TA based only on dimensions. Confirm the original housing, seal profile and installation requirements first.
SB and SA are both spring-loaded single-lip oil seals.
The SB Oil Seal uses a standard metal outer case, while the SA Oil Seal features a reinforced metal outer structure.
An SB Oil Seal is suitable for conventional single-lip sealing applications, while an SA Oil Seal may be selected where greater structural rigidity of the seal case is required.
One of the most important selection considerations is the outer diameter construction.
A TB Oil Seal uses an exposed metal outer diameter, while common TC Oil Seals use a rubber-covered OD.
Metal-case oil seals provide a firm and accurate press fit in properly machined metal housings. However, because the outer diameter is less flexible than a rubber-covered surface, the housing bore condition becomes more important.
A rubber-covered oil seal can provide additional conformity against minor housing surface imperfections, while a metal-case seal is often selected when a rigid, accurately controlled installation is required.
Therefore, TB should not automatically replace TC simply because their dimensions are identical.
TB Oil Seals can be used in rotating shaft assemblies requiring reliable lubricant retention together with external contamination protection.
Typical applications include:
● Automotive transmissions
● Gearboxes
● Engines
● Axles and differentials
● Electric motors
● Pumps
● Agricultural machinery
● Construction machinery
● Industrial drive systems
● General rotating equipment
The exact seal structure should always be matched to the installation position and operating conditions.
A double-lip structure is not necessary in every application.
If the sealing position is enclosed or operates in a relatively clean environment, an SB Oil Seal may provide the required oil retention without an additional dust lip.
SB may therefore be considered when:
● External contamination is minimal.
● Only one primary sealing lip is required.
● The housing requires a metal outer case.
● The original seal uses an SB structure.
For dusty, dirty or exposed environments, TB may provide better contamination protection because of its secondary lip.
TA Oil Seal and SA Oil Seal should be evaluated when the application requires a more reinforced metal-case construction.
Choose between them according to the required sealing lips:
● TA Oil Seal: reinforced metal case + double lip.
● SA Oil Seal: reinforced metal case + single lip.
TA is better suited when both lubricant retention and an additional contaminant barrier are required, while SA can be used where a single sealing lip is sufficient.
The required case strength also depends on seal diameter, housing geometry and installation method.
Selecting the correct TB Oil Seal requires more than matching three dimensions.
Before ordering, confirm:
● Inner Diameter (ID) – shaft diameter at the sealing position
● Outer Diameter (OD) – housing bore diameter
● Width – available installation depth
● Oil Seal Structure – TB, SB, TA or SA
● Material – NBR, FKM or other required compound
● Lubricant – oil, grease or other medium
● Operating Temperature
● Shaft Speed
● Housing Bore Condition
● Dust and contamination level
● OE or part number
● Vehicle or equipment application
This information helps prevent incorrect cross-referencing between seals that have similar dimensions but different structures.
The sealing material should be selected according to temperature, lubricant and operating conditions.
NBR is commonly used for general oil and grease sealing applications because of its good oil resistance and cost efficiency.
FKM can be considered for applications involving higher operating temperatures or more demanding oil and chemical conditions.
Material selection should always be based on the actual working environment rather than the oil seal type alone.
Because a TB Oil Seal has a metal outer diameter, correct housing preparation is particularly important.
Before installation:
● Check the housing bore for damage, burrs or contamination.
● Confirm that the bore diameter matches the specified seal OD.
● Avoid damaging or deforming the metal case during pressing.
● Apply installation force evenly around the seal.
● Check the shaft sealing surface for grooves, scratches or excessive wear.
● Lubricate the sealing lip appropriately before initial operation when required.
Improper housing or shaft conditions can cause leakage even when the correct oil seal size has been selected.
If you are unsure which metal case oil seal is required, provide TBT with:
● ID × OD × Width
● OE or part number
● Photos of both sides of the existing seal
● TB / SB / TA / SA structure if known
● Rubber material requirement
● Vehicle or equipment model
● Installation position
● Sealing medium and operating conditions
We can help identify a suitable TB Oil Seal, SB Oil Seal, TA Oil Seal or SA Oil Seal and provide standard or customized sealing solutions for automotive and industrial applications.
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