Rotary Shaft Oil Seal 25x35x7 mm NBR TC - Double Lip Oil Seal

Characteristics of the 25x35x7 NBR TC Oil Seal

The 25x35x7 NBR TC oil seal is designed to seal the space between a rotating shaft and a stationary machine housing.

Its primary function is to retain compatible lubricants inside mechanical assemblies. The additional dust exclusion lip helps reduce the entry of external contaminants toward the main sealing interface.

Key characteristics:

• Nominal shaft diameter: 25 mm.

• Nominal housing bore diameter: 35 mm.

• Axial seal width: 7 mm.

• Elastomer material: NBR - nitrile butadiene rubber.

• Profile: TC - double lip construction.

• Spring-loaded primary sealing lip.

• Additional dust exclusion lip.

• Rubber-covered outside diameter.

• Internal metal reinforcing insert.

• Dynamic radial shaft sealing.

• Designed for retaining compatible oils and lubricants.

NBR is widely used in rotary shaft seals because of its resistance to many mineral-based lubricating oils and greases. Chemical compatibility depends on the specific fluid, operating temperature and application conditions.

Technical Specifications

The specifications describe the supplied dimensions, material and conventional TC profile construction. Manufacturer-specific values such as exact NBR hardness, maximum surface speed, operating pressure, temperature range, mass and EAN have not been independently verified for this particular product and are therefore omitted.

What Does 25x35x7 NBR TC Mean?

25x35x7 mm - Nominal Dimensions

The dimensional designation identifies three principal measurements:

• 25 mm - nominal shaft diameter.

• 35 mm - nominal housing bore diameter.

• 7 mm - axial width of the oil seal.

These dimensions must match the requirements of the shaft, housing and original sealing arrangement.

NBR - Nitrile Butadiene Rubber

NBR is a synthetic elastomer commonly used in industrial oil seals and mechanical sealing components.

Its characteristics include:

• Resistance to many mineral-based lubricating oils.

• Compatibility with numerous conventional lubricating greases.

• Elastic sealing performance under suitable operating conditions.

• Wear resistance when correctly lubricated.

NBR is not universally compatible with all chemicals, fuels, solvents or hydraulic fluids.

The material must be selected according to the actual medium and operating conditions.

TC - Double Lip Seal Profile

TC is a commonly used designation for a radial shaft seal with:

• A spring-loaded primary sealing lip.

• An additional dust exclusion lip.

• A rubber-covered outside diameter.

• Internal metal reinforcement.

The primary lip retains the lubricant, while the auxiliary lip helps limit the entry of external dust and contaminants.

The TC profile corresponds to a commonly used double lip construction. Exact profile equivalence between manufacturers should be confirmed before substitution.

Construction and Operating Principle

Primary Sealing Lip

The main sealing lip is manufactured from NBR and operates in direct contact with the rotating shaft.

Its purpose is to limit lubricant leakage from the machine housing.

Correct sealing performance depends on the shaft surface condition, lip geometry, lubrication and operating parameters.

Garter Spring

A circular garter spring supports the primary sealing lip.

It helps maintain radial contact pressure between the sealing lip and shaft surface.

The spring is positioned on the main sealing lip side of the seal.

Additional Dust Exclusion Lip

The TC profile incorporates an auxiliary dust lip on the external side of the seal.

This lip helps reduce the entry of dust and small contaminants toward the primary sealing interface.

It does not make the seal completely resistant to pressurised water, abrasive particles or severe contamination.

Rubber-Covered Outside Diameter

The rubber-covered outer surface provides static sealing between the oil seal and housing bore.

The nominal housing bore diameter is 35 mm.

The elastomeric outer surface can accommodate minor surface irregularities within the applicable installation tolerances.

Internal Metal Reinforcement

The internal metal insert supports the seal body and helps maintain its geometry during installation and operation.

25x35x7 NBR TC vs SC Oil Seals

Oil seals with identical dimensions may have different lip arrangements.

TC - Double Lip Design

The TC profile includes an additional dust exclusion lip that helps protect the primary sealing area against external contamination.

SC - Single Lip Design

The SC profile has one primary spring-loaded sealing lip without an additional dust exclusion lip.

TC and SC oil seals are not automatically interchangeable, even when their nominal dimensions are identical.

The correct profile depends on the original equipment design, contamination exposure, friction requirements and operating conditions.

Oil Seal Selection and Interchangeability

Before purchasing or replacing a 25x35x7 NBR TC oil seal, verify the following:

1. Nominal shaft diameter of 25 mm.

2. Nominal housing bore diameter of 35 mm.

3. Seal width of 7 mm.

4. NBR elastomer material.

5. TC double lip profile.

6. Spring-loaded primary sealing lip.

7. Additional dust exclusion lip.

8. Compatibility with the sealed fluid.

9. Shaft surface condition, hardness and roughness.

10. Shaft surface speed.

11. Operating temperature.

12. Pressure acting on the seal.

13. Lubrication conditions.

14. Exposure to dust, dirt and external contaminants.

Identical dimensions do not guarantee complete interchangeability between seals of different profiles, materials or manufacturers.

Typical Applications of Double Lip NBR Oil Seals

Double lip NBR rotary shaft seals are commonly used in appropriately designed mechanical assemblies involving rotating shafts.

Typical applications of this seal type include:

• Industrial gearboxes.

• Bearing housings.

• Mechanical drive systems.

• Oil-lubricated rotating shaft assemblies.

• Industrial machinery with rotating components.

• Equipment requiring additional protection of the primary sealing area against dust.

These are general applications of the TC seal construction and do not establish confirmed compatibility with any specific machine model or OEM part number.

Installation and Operating Recommendations

Before installation, inspect the shaft surface for scratches, corrosion, burrs and wear grooves.

The housing bore must be clean and free from damage.

Install the seal evenly using a suitable mounting tool that applies force to the appropriate area of the seal body.

Avoid damaging either sealing lip when passing the seal over threads, keyways or sharp shaft edges.

Before operation, ensure that the primary sealing lip is properly lubricated.

The space between the primary lip and dust lip may also require appropriate lubrication according to the seal design and application.

In a typical oil-retaining arrangement, the spring-loaded side of the seal should face the lubricant being retained, while the auxiliary dust lip faces the external environment.

Avoid dry running, as it may increase friction, operating temperature and premature elastomer wear.

Unused oil seals should be stored in clean, dry conditions away from direct sunlight, excessive heat and ozone-producing equipment.

Alternative Designations and Search References

The product may be identified using the following formats:

• Rotary shaft oil seal 25x35x7 NBR TC

• Oil seal 25x35x7 NBR TC

• 25x35x7 NBR TC

• Double lip oil seal 25x35x7

• Radial shaft seal 25x35x7 NBR

• Shaft seal 25x35x7 TC

• Simmering 25x35x7 NBR TC

These references describe the dimensions, material and sealing profile. They are not verified OEM part numbers or guarantees of interchangeability between manufacturers.

FAQ - 25x35x7 NBR TC Oil Seal

1. What are the dimensions of the 25x35x7 NBR TC oil seal?

The nominal shaft diameter is 25 mm, the housing bore diameter is 35 mm and the seal width is 7 mm.

2. What does TC mean on an oil seal?

TC identifies a double lip rotary shaft seal with a spring-loaded primary sealing lip, an additional dust exclusion lip and a rubber-covered outside diameter.

3. Does a TC oil seal have two garter springs?

No. A conventional TC seal has one garter spring supporting the primary sealing lip. The auxiliary dust exclusion lip normally has no separate spring.

4. Is the 25x35x7 NBR oil seal suitable for oil?

NBR is resistant to many mineral-based oils and lubricating greases. Compatibility must be verified for the specific fluid and operating temperature.

5. Can a TC oil seal be replaced with an SC oil seal?

Not automatically. An SC oil seal does not have the additional dust exclusion lip found in a TC design, which may reduce protection against external contamination.

6. Is this oil seal suitable for a 25 mm shaft?

Yes. The 25 mm dimension identifies the nominal shaft diameter for which the primary sealing lip is designed.

7. Does a TC oil seal require lubrication?

Yes. The primary dynamic sealing lip requires appropriate lubrication. Depending on the application, lubrication may also be required in the space between the primary lip and auxiliary dust lip.

8. Which direction should a TC oil seal face during installation?

In a typical oil-retaining application, the side containing the garter spring should face the lubricant, while the auxiliary dust lip faces the external environment.

25x35x7 NBR TC Oil Seal - Key Technical Information

The 25x35x7 NBR TC is a double lip rotary shaft oil seal designed for a 25 mm shaft and 35 mm housing bore, with a width of 7 mm. Its nitrile rubber construction includes a spring-loaded primary sealing lip and an additional dust exclusion lip. The TC profile helps retain compatible lubricants while limiting external contamination.

The product is available through simmering.pl, a specialist supplier of industrial rotary shaft seals, oil seals, bearings and technical sealing components.

With warehouse operations in Lublin, Poland, simmering.pl serves industrial maintenance departments, machinery manufacturers and international B2B customers, with worldwide shipping options.