What is Oil Seal | Purpose , types of Oil Seal , Advantages

 

What is oil seal | Purpose , Types of Oil Seal , Advantages

 

 

 

 

OIL SEAL

 

 

Oil seals, also known as shaft seals, are radial lip type seals which are primarily used for retaining lubricants in equipment having rotating, reciprocating or oscillating shafts. The rotating shaft application is most common.

 

 

An oil seal normally consists of three basic components: the sealing element, the metal case and the spring. The purpose of the sealing element is to stop the fluid from leaking between the shaft and housing. The metal case will give rigidity and strength to the seal while it is being held in the bore or recessed groove. The garter spring ensures constant pressure and maintains the radial force to the shaft, flattening the sealing edge to a defined width. The garter spring maintains the radial force exerted by the sealing lip around the shaft surface. All materials must be selected depending on the environment in which the oil seal will function.

The performance of these seals depends to a large extent on a suitable unit load being maintained at the seal-shaft interface. These seals withstand a pressure of 15PSI and their working depends on parameters like shaft diameter, shaft speed, working temperature, service conditions, etc

 

Oil seals or shaft seals are an integral part in any rotating and moving part assembly. Oil seals find great deal of usage in gearboxes, hydraulic cylinders, etc. The usage of the seals in areas concerned with motion also earns them a name of “Dynamic Oil Seals.”

 

 

 

 

The purpose of the oil seals is

 

 

To act as a physical barrier retaining the lubricating oil where it is bound to be.

To prevent thelubricating oil from leaking outside even under high pressure of the oil.

To act as a barrier and prevent dirt, contamination and other external entities from entering the system containing the lubricating oil.

 

 

 

Constructional Aspects of an Oil Seal:

 

 

1. The oil seal consists of a metal ring as the inner skeleton which provides the structural stability to the oil seal.

2. The outer skin is made of nitrile rubber and various other materials which are used based on the requirement.

 

3. The spring on the lip of the oil seal tends to provide support to the lip and prevents the lubricant from leaking outside and also prevents the entry of contaminants from outside.

 

 

TYPES OF OIL SEAL

 

 

 

 

Double Lip Oil Seals

 

 

In this an auxiliary lip is provided along with the regular sealing lip. The additional dust lip protects the main sealing lip against dust and other fine solid contaminants and therefore this type is recommended for use in polluted environments. To achieve a long lifetime a suitable lubricant between the two sealing lips should be applied.

Advantages:
– Good static sealing
– Compensation of different thermal expansion
– Reduced risk of fretting corrosion
– Effective protection against air side contaminants
– Higher bore surface roughness is allowed
– Installation in split-housings
– Modern lip design provides low radial forces

 

 

 

Duplex Oil Seals

 

 

Sometimes, two different kinds of fluids leak from one chamber to another and gets mixed up. Here, this type comes as a boon. This is a metal inserted duplex type oil seal recommended on such assembly where mix-up of two different fluids is to be prevented.

 

 

Oil Seals without Spring

 

This type of oil seal can withstand only low speed and friction. It is recommended in places where thick fluid or grease is to be sealed. This is not recommended for difficult applications.

Material:

Oil seals are made out of nitrile synthetic rubber with steel stiffener rings. Other rubbers such as viton, silicon, neoprene or poly acrylic can be used for specific applications. The stiffener rings may be stainless steel or brass where highly corrosive fluids are to be sealed. Springs are generally made of spring steel to IS: 4454:Gr.ll or from stainless steel or bronze for corrosion resistance

 

 

 

Type A Oil Seals

 

 

Sealing of lip type seal is normally a result of an interference fit between the flexible sealing element, usually augmented by spring pressure and a shaft. Fluid retention is based on the precise amount of lip contact pressure. In most lip seals, increased fluid pressure in the sealed area causes lip contact pressure on the shaft to increase.

Advantages:
– Good static sealing
– Compensation of different thermal expansion
– Reduced risk of fretting corrosion
– Higher bore surface roughness is allowed
– Installation in split-housings
– Modern lip design provides low radial forces

 

 

 

Type B Oil seals

 

 

This is almost similar to that of ‘A’ type seal. But this has the metal case placed outside. When the housing is rough, temperature is high and working conditions are severe, this type is preferred.

 

 

 

Type C Oil seal

 

 

Type ‘C’ oil seal has an additional cup inserted into the outer cup of ‘B’ type. The supplementary metal inner ring provides a superior stiffness. This type is recommended for use in heavy polluted environments. As the static sealing between housing and metallic shell is limited, low viscosity media can “creep”.

Advantages:
– Very good fitting stability avoiding pop-out of the seal
– Modern lip design provides low radial forces
– Superior radial stiffness, especially for very large diameters
– Cost effective for expensive elastomer materials
– Suitable for use in combination with axial seal

 

 

Material used for Oil Seal :

 

Based on the application of the oil seal, the outer skin layer tends to differ. Here are some types of the materials used for the outer skin of the oil seal.

1. Nitrile rubber – The commonly used material for oil seals

2. Silicone – Used in specific applications where only light loads are applied.

3. Poly acrylate

4. Fluroelastomer also popularly known as Viton. – The high temperature resistant material used in places where temperature is more than 120 Degree Celcius.

5. PolytetraFluroEthylene (PTFE)

The oils seals require certain prerequisites to be maintained for their proper working. They are as follows:

a) The shaft on which the oil seal is to be mounted should be ground with the surface finish or surface roughness between 0.2 to 0.8 Microns. It is best for the shaft to be hardened atleast to 40 – 45 HRc in order to prevent groove formation on the shaft due to the pressure exerted by the spring.

b) The area where the oil seal is seated is to be plunge ground in order to prevent wear grooves that normally tend to wear out the lip of the oil seal at a faster rate.

 

 

 

 

 

Sachin Thorat

Sachin is a B-TECH graduate in Mechanical Engineering from a reputed Engineering college. Currently, he is working in the sheet metal industry as a designer. Additionally, he has interested in Product Design, Animation, and Project design. He also likes to write articles related to the mechanical engineering field and tries to motivate other mechanical engineering students by his innovative project ideas, design, models and videos.

 

 

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Oil seals in our inventory, we also do speciality styles.

Home > Products > Oil Seals

Oil Seals

Note: We have many types of standard oil seals and specialty oil seals, so please call so we can help you pick out exactly what you need.

In terms of overall seal design, the following will give a brief explanation of some of the broad oil seal categories we commonly work with. Oil seals are classified according to the sealing element and the structure. The classification by sealing element corresponds to the first letter in the oil seals P/N style. The classification by structure corresponds to the second letter.

Classification by Element:

S: Standard oil seals with a single sealing lip design. They are used to seal against internal media.
Limitations: Peripheral Speed: 12 m/sec
Temperature: 120°C (250°F)
Pressure: 0.3 Kg/cm2 (5-10 psi)

T: Oil seals with a double sealing lip design. The main lip seals against internal media, while the auxiliary lip (dust lip) provides protection against external dirt and dust.
Limitations: Peripheral Speed: 10 m/sec
Temperature: 120°C (250°F)
Pressure: 0.3 Kg/cm2 (5-10 psi) V: An oil seal design where no spring is loaded. The flexible sealing element is used to seal internal media. It is suitable for sealing grease and protecting against dirt and dust. It can also be used along with other types of seals.
Limitations: Peripheral Speed: 8 m/sec
Temperature: 120°C (250°F)
Pressure: 0 Kg/cm2 (3 psi) K: Oil seals where no spring is loaded. The flexible sealing element is used to seal against both internal and outer media and provides protection against dirt and dust.
Limitations: Peripheral Speed: 5 m/sec
Temperature: 120°C (250°F)
Pressure: 0 Kg/cm2 (3 psi) D: This oil seal style is intended for sealing against both internal and external media. It is usually used to separate two liquids. The area between the two lips must be lubricated with grease, etc.
Limitations: Peripheral Speed: 5 m/sec
Temperature: 120°C (250°F)
Pressure: 0.3 Kg/cm2 (5-10 psi) TX4: This design for oil seals is intended for reciprocating motion (not for rotary), especially for pressurized media.
Limitations: Reciprocating Speed: 0.3m/sec
Temperature: 120°C (250°F)
Pressure: 7Kg/cm2 (100 psi)

Classification by Structure:

Code Characteristics C A rubber covered case - can be used on any shaft size. It prevents the metal case from rusting, corrosion, and prevents damage to the housing bore during assembly. Also, it is the most effective structure design to prevent bore leakage in oil seals. B/BX2 A metal case - mainly used on shafts for which the diameters are below 150 mm. A/AX2 A reinforced case - mainly used on shafts larger than 150 mm, or smaller shafts that require extra strength in the metal case. BC Rubber covered "end-cap" plug - solid caps and no center hole. For sealing additional shaft location holes (shaft added later). For multiple hole housings requiring seal plug for unused shaft holes.
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Oil-Seals

We at Oil-Seal-Stock offer you a wide range of Oil Seals. For example, we have combined Oil-Seals with a dust lip, cassette seals, a seal with a spring, high-pressure oil-seals and these specifications.

Wir von Oil-Seal-Stock bieten Ihnen ein breites Sortiment an Wellendichtungen. Wir haben Wellendichtung mit Staublippe, Kassettendichtungen, Wellendichtung mit Feder, Hochdruckwellendichtung und diese Spezifikationen kombiniert.

Chez Oil-Seal-Stock, nous vous proposons une large gamme de joints radiaux. Par exemple, nous avons combiné des joints radiaux avec une lèvre anti-poussière, des joints à cassette, des joints radiaux avec un ressort, des joints radiaux haute pression et ces spécifications.

Noi di Oil-Seal-Stock ti offriamo una vasta gamma di Guarnizioni Radiali. Ad esempio, abbiamo abbinato Guarnizioni Radiali con un labbro parapolvere, guarnizioni a cassetta, Guarnizioni Radiali con una molla, Guarnizioni Radiali ad alta pressione e anche queste specifiche.

En Oil-Seal-Stock ponemos a su disposición una amplia gama de Sellos Radiales. Por ejemplo, hemos combinado Sellos Radiales con guardapolvo, sellos de cassette, Sellos Radiales con resorte, Sellos Radiales de alta presión y estas especificaciones.

Applications

Oil-Seals are often used in the construction of engines, industrial drives, gearmotors, electric motors, combustion engines, pumps, drive systems, agricultural machinery, construction machinery and many more applications.

*Please note: we deliver high quality Oil Seals, however our oil seals are not suitable for the automotive industry. When used in Automotive, we cannot take responsibility.

Versions

Our Oil-seals can be described in three different types. For example, we have a type with an elastomer outer jacket, which guarantees a very good static seal. In addition, we have a seal with a metal outer jacket, which ensures that there is an accurate fit in the housing. Finally, we have installed a type with an additional metal ring for reinforcement, which is more suitable as an oil seal in difficult mounting conditions and rough conditions.

Materials

Our oil-seals are available in different materials. We have seals in FKM, NBR, VMQ, HNBR and much more. We have Garlock PS-Seals that have to function under special circumstances. These seals can be used, for example, in the food industry and pharmacy. Find more information about our Garlock PS-Seals here.

Wondering what material you need? View all specifications of Oil Seal Materials?

Requirements

Leak-free in all operational conditions

Easy assembly

Low friction, low power loss, low heat generation

Oil-Seals have many different names. Oil-Seals are also called Simmerings or Radial Shaftseals. The names of different types of seals can also differ at different factories, in the end the only thing that is different is the name of that type of seal. All our seals have the names of each factory that produces this type in the description.

Not sure what size you need? Or do you not know how to measure an oil seal size? See here how to measure an oil seal!

If you would like more information about Oil-Seals or if you do not know which Seal you should have, please feel free to contact us.

Also view our range of Domsel Oil Seals here!

Maybe interested in our high-quality Freudenberg Oil-Seals (Simmeringen)? Take a look at our Freudenberg Sealing Technologies website!