Oil seals are widely used as sealing devices for machines.
JTEKT's oil seals are described in our catalog, Oil Seals & O-Rings.
However, the catalog uses a large number of technical terms and is very long, so many people seem to have trouble handling it.
Therefore, this series of columns will summarize the following in order:
• The structure, functions, and types of oil seals
• How to select the right oil seal
• Handling of seals, and causes and countermeasures for oil seal failure
NNK contains other products and information you need, so please check it out.
A wide range of sealing devices are used in various machines.
Sealing devices serve the following functions:
As shown in Figure 1, sealing devices come in two types: contact and non-contact.
Oil seals are among the major contact type sealing devices.
Figure 1: Types of sealing devices
Please see the following for the types of sealing devices for bearings.
How to Select the Right Bearing (Part 7): Components surrounding the bearing
Oil seals come in various shapes to fit the machines and substances to be sealed.
Figure 2 shows the structure and the names of the various components of the most typical oil seal.
The functions of the various components are also indicated in Table 1.
Figure 2: Typically shaped oil seal and component nomenclature
* "KOYO" is a registered trademark of JTEKT.
Table 1: The functions of the various components
No.
Name
Functions
①
Main lip The main lip is the most critical component of the seal.
Its sealing edge comes in full contact with the shaft surface in order to provide excellent sealing performance.
(See Figure 3.)
②
Minor lip The minor lip prevents the entry of dust and contaminants from outside.
Lubricant can be retained in the space between the main lip and the minor lip.
③
Sealing edge This refers to the component of the oil seal that makes contact with the shaft.
It is wedge-shaped to be pressed against the shaft surface and makes contact with the shaft to ensure sufficient sealing performance and suitability for operation at high peripheral speed.
④
Spring The spring supplements the tightening force (i.e., the lip radial load) to ensure enhanced sealing performance and tight contact between the shaft and the sealing edge.The spring also prevents the deterioration of main lip sealing performance caused by high heat or other such factors.
⑤
Metal case The metal case provides rigidity to the seal, helping it settle on the housing securely. It also ensures easy seal handling and mounting.
⑥
O.D. (outside diameter) surface The O.D. surface affixes the oil seal to the housing and prevents leakage , through the fitting area, of substances to be sealed, while excluding contaminants.
⑦
Fluid side face The front-end face of the seal is called the nose. The nose is made of rubber and forms a gasket seal when compressed on the housing shoulder.
⑧
Air side face The oil seal surface vertical to the center line of the shaft on the side that does not come in contact with substances to be sealed is called the back face.
Figure 3: Sealing function of main lip radial load
* "KOYO" is a registered trademark of JTEKT.
Figure 4 shows the features of a JTEKT oil seal.
Figure 4: JTEKT oil seal features
For more detailed information, please see the following:
Names and functions of seal components
Seals are classified by O.D. wall material, lip type, and whether they have a spring or not.
Major oil seals are specified in ISO -1 and JIS B -1.
Table 2 shows the common types of oil seals, while Table 3 shows the features of each type of oil seal.
Table 4 lists the JTEKT oil seal type codes and corresponding ISO and JIS standards.
Table 2 a): Common types of oil seals (with spring)
With spring Rubber O.D. wall Metal O.D. wall
Metal O.D. wall
(with a reinforcing inner metal case)
Without minor lip
Type code
With minor lip
Type code
Table 2 b): Common types of oil seals (without spring)
Without spring Rubber O.D. wall Metal O.D. wall
Without minor lip
Type code
With minor lip
Type code
Table 3: Features of each seal type
No.
Type
Features
1
With spring type Secures stable sealing performance.
2
Rubber O.D. wall type Provides stable sealing performance around the seal O.D. surface.
3
Metal O.D. wall type Ensures improved fitting retention between the seal O.D. and the housing bore.
4
Metal O.D. wall type (with a reinforcing inner metal case) Protects the main lip.
5
With minor lip type Used for applications where there are contaminants, such as dust and foreign matter, on the air side face of the oil seal.
Table 4: JTEKT oil seal type codes and corresponding ISO and JIS standards
JTEKT
ISO -1 1)
JIS B -1 2) MHS Type 1 HMS Type 2 HMSH Type 3 MH － HM － MHSA Type 4 HMSA Type 5 HMSAH Type 6 MHA － HMA －
Notes
1) ISO: International Organization for Standardization
2) 2) JIS: Japanese Industrial Standard
JTEKT provides special seals for use in a wide variety of machines and applications.
Table 5 lists the major special seals, their shapes, and their features.
Table 5: The major special seals, their shapes, and their features
Name Type
(type code) Shape Features
Helix Seal
The hydrodynamic ribsa) provided in one direction on the air side face of the lip ensure higher sealing performance. Perfect Seal The hydrodynamic ribsa) provided in two directions on the air side face of the lip ensure higher sealing performance (higher sealing performance in both rotational directions of the shaft).
Super Helix Seal
The hydrodynamic ribsa) have a two-stepped rib configuration provided in one direction on the air face of the lip. Even if the first rib is worn out, the second rib comes into contact with the shaft surface, meaning that this type of oil seal ensures higher sealing performance. Seal with Side Lip A large side lip ensures prevention of entry of dust/water.
a)
Function of hydrodynamic ribs
For more detailed information, please see the following:
Special seal types and their features
Figure 5 explains the JTEKT seal numbering system.
Seal numbers consist of
(1) the seal type code,
(2) the spring code,
(3) the lip type code,
(4) the dimensional numbers, and
(5) the special type code,
and Table 6 shows examples of each of these codes/numbers.
Figure 5: JTEKT seal numbering system
Table 6: Codes and numbers used in seal numbers
No. Code and number Example ① Seal type code (*)
MH: O.D. wall is a rubber material
HM: O.D. wall is a metal case
MH(S)H: O.D. wall is metal with a reinforced inner metal case
② Spring code
No code: without minor lip
A: with minor lip
③ Lip type code
No code: without minor lip
A: with minor lip
④ Dimensional numbers Shaft number 45: The seal suits the shaft diameter of ϕ45 mm. Housing bore number 70: The seal suits the housing bore diameter of ϕ70 mm. Width number 8: The seal width is 8 mm. ⑤ Special shape code
J: Additional code is added here as an identifier when two or more seals have exactly the same type codes and dimensional numbers.
Note: For seal type codes, see Table 2.
Oil seals are used in a great many machines.
Oil seals are used in many areas around the car.
Figure 6 shows the places where each seal type is used.
Figure 6: Oil seals for cars
For more detailed information, please see the following:
Oil seals for cars
Oil seals are used in a great many devices for steel production equipment.
Figure 7 shows the places where each seal type is used in a rolling mill.
Figure 7: Oil seals for steel production equipment (rolling mill)
For more detailed information, please see the following:
Oil seals for steel production equipment
If you want to learn more, please visit our website chinese engine oil seal.
Oil seals are one of the major contact type sealing devices.
• They prevent leakage of the lubricant or other sealed substance, and
• prevent entry of dust and foreign matter (dirt, water, metal powder, etc.) from outside.
Oil seals come in various shapes to fit the machine or substance for sealing.
For this reason, when designing a machine, it is important to select the oil seal that is right for that machine.
Next time, we will explain the key points to consider when selecting your oil seal.
If you have any technical questions regarding oil seals, or opinions/thoughts on these "Bearing Trivia" pages, please feel free to contact us using the following form:
Oil seals, also referred to as shaft seals, are widely used to prevent the leakage of medium (such as oils and grease) along a rotating shaft. This leak prevention is primarily achieved by the sealing element which can be made from a wide range of materials that are chosen according to each application. They are commonly used in gearboxes, hydraulic cylinders, and related components.
An oil seal is designed to perform three major functions: to prevent lubricants from leaking outside the seal even under high pressure, to act as a barrier to retain the lubricating oil, and to prevent dirt and other contaminants from entering the unit.
Shop for Oil Seals
Oil seals normally consist of three basic components: the sealing element, the metal case, and garter spring.
The sealing element makes up the interior of the oil seal, and the materials commonly used are:
The metal case is the exterior (or frame) of the oil seal, the principal function of which is to give rigidity and strength to the seal. The material of the case must be selected depending on the environment where the seals are to be used. Often the metal case is covered by the same rubber material used in the sealing element, which also helps seal the exterior of the oil seal in the housing bore. Common case material types are:
The garter spring is located at the end of the primary sealing lip and used to apply pressure to the sealing lip against the shaft. Common garter spring material types are:
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: :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.
Are you looking for the best engine oil leak seal manufacturers in China? With so many options available, it can be overwhelming to choose the right one. In this article, we’ll compare the top engine oil seal factories in China, highlighting their strengths, product ranges, and what sets them apart. Let’s dive in and find the perfect fit for your needs.
Product Details: TC oil seals are mechanical components used to seal oil and other fluids in various mechanical systems. They are typically made from materials such as NBR, FKM, and silicone, and feature a single metal cage with a rubber coating, a primary sealing lip with an integrated spring, and an additional anti-pollution lip. These seals are designed to isolate parts that need lubrication from output parts, preventing oil leaks. They are widely used in engines, transmissions, rear axles, and other applications in vehicles, construction machinery, and industrial equipment. Customization is available, and sizes range from standard to customized dimensions.
Pros:
– Better sealing performance and reduced leakage problems
– Less friction and lower energy consumption
– Longer service life and more convenient installation
– High temperature and pressure resistance
– Good static sealing and thermal expansion compensation
– Reduced risk of corrosion and effective sealing for low and high viscosity fluid…
Cons:
– May require periodic replacement due to wear and tear
– Can be affected by the quality of the raw materials used
– Installation and maintenance may require specialized skills and tools
– May not be suitable for all types of fluids or operating conditions without prop…
Product Details: The ‘China Wall’ refers to the area between the intake manifold and the engine block in certain engine designs, particularly in Chevrolet Corvettes and other vehicles. This area is prone to oil leaks due to the mating surfaces between the intake manifold and the engine block. To address this, various sealing methods are employed.
Pros:
– Using RTV (Room Temperature Vulcanization) sealant can effectively seal the mati…
– Drilling small holes or dimpling the surfaces can provide anchors for the sealan…
Cons:
– Improper cleaning and application of RTV can lead to ineffective sealing and pot…
– Overuse of RTV can result in it getting loose within the engine, causing further…
Product Details: The discussion revolves around a Ford F-400 truck experiencing repeated leaks from the rear china wall gasket. The truck is likely equipped with a Ford 385 engine or another engine relevant to the era.
Pros:
– The Ford 385 engine, if equipped, is known for its durability and power output,…
– The truck’s design and build quality were generally robust for its time.
Cons:
– The repeated leaking from the rear china wall gasket indicates a potential issue…
– Maintenance and parts for older trucks can be challenging due to the age and pot…
Product Details: NNK offers a wide range of rubber oil seals, including power steering oil seals, TC and TG4 rubber oil seals, construction machinery oil seals, valve stem seals, and cassette wheel hub oil seals. Their power steering oil seals are designed to prevent dust, sand, and water from entering the steering system and keep gears lubricated. The TC and TG4 rubber oil seals are suitable for shaft sealing, motors, pumps, and transmissions, and feature good static sealing, thermal expansion compensation, and reduced risk of corrosion. Construction machinery oil seals are available for motor, gear reducer, gearbox, pump, and other applications, providing
strong sealing effects and reduced friction. Valve stem seals have a low friction design and can withstand aggressive corrosives, ensuring long-term emissions control and service life.
Pros:
– Complete range of models and sizes available
– High efficiency and durability
– Good static sealing and thermal expansion compensation
– Reduced risk of corrosion
– Sealing for low and high viscosity fluids
– Modern primary sealing lip with low radial forces
– Long service life and resistance to aggressive corrosives
– Improved reliability and extended service life of oil seals
Cons:
– No specific cons mentioned on the website
– No information on potential drawbacks or limitations of the products
Product Details: The discussion revolves around a Chinese 4k generator that is experiencing an oil leak from the joint where the two engine case halves join. This joint is sealed by a gasket. The user is seeking advice on how to address this issue without having to split the case.
Cons:
– Oil leak from the engine case joint, which can be problematic and require signif…
– Potential need to split the engine case to replace the gasket, which is a major…
Product Details: The discussions revolve around addressing oil leaks in engine components, particularly the ‘china wall’ area between the intake manifold and engine block. Common products mentioned include intake gasket kits, RTV silicone sealants, and thread sealants.
Pros:
– Using high-strength RTV silicone sealants can provide a more durable seal compar…
– Properly sealing the china wall area can significantly reduce oil leaks.
– Teflon tape or Loctite thread sealant can enhance the seal on sensor threads.
Cons:
– Improper installation or poor fitment of the intake manifold can lead to persist…
– Using only silicone as a gasket can result in worse leaks, especially if the sur…
– Blockages or restrictions in the crank-case vent/PCV system can exacerbate oil l…
Product Details: KDIK oil seals manufacture a wide range of industrial seals, including oil seals for automobile, agricultural, and construction machinery. Their products include Concrete Mixer Gearbox Oil Seals, Hydraulic Pump Oil Seals, and various types of oil seals for tractors, trucks, and other heavy equipment. The seals are designed for high performance, extended equipment life, and enhanced productivity. They offer combined oil and dust seals in one metal case for extreme wear applications and provide sealing solutions to prevent leakage of oil and lubricants. The seals are available in various sizes and materials, such as NBR, and are certified with ISO/Ts
standards[2][4][5].
Pros:
– High performance and extended equipment life
– Enhanced productivity
– Wide range of sealing solutions for different applications
– Advanced production equipment and technology
– Certified with ISO/Ts standards
– Global export to over 100 countries
Cons:
– Limited information on specific product warranties
– Dependence on advanced technology which may require specialized maintenance
– Potential quality variations in mass production
Product Details: The discussion revolves around addressing oil leaks at the ‘china wall’ area between the intake manifold and the engine block. Methods include using either rubber seals or RTV (Room Temperature Vulcanization) sealant. The user has tried using RTV previously but encountered leaks, and is now considering a combination of rubber seals and RTV.
Pros:
– Using a combination of rubber seals and RTV can potentially provide a more secur…
– Cleaning the surfaces with lacquer thinner and creating dimples in the sealing s…
Cons:
– Using RTV alone has resulted in leaks in the past for the user.
– There is discrepancy and uncertainty among users regarding whether to use rubber…
Product Details: Chinese oil seal manufacturers produce a wide range of oil seals, including TC oil seals, EC oil seals, rubber oil seals, O-rings, and mechanical seals. These products are used in various industries such as automotive, agricultural machinery, construction machinery, and industrial equipment. Companies like Xingtai Honglei Seal Manufacturing Co., Ltd., Ningbo Shenlian Rubber Sealing Elements Co., Ltd., and SBT Oil Seal offer customized designs and OEM services. Their products include automobile oil seals, wheel hub oil seals for tractors, valve stem seals, and precision rubber parts[1][4][5].
Pros:
– High-quality product delivery with advanced testing facilities and strict qualit…
– Large production capacity and extensive global reach, catering to markets in Eur…
– Reasonable prices and competitive pricing strategies[1][4].
– Strong research and development capabilities, ensuring continuous innovation and…
– Ability to accept customer’s own designs and OEM orders, providing flexibility a…
Cons:
– Dependence on global market conditions and logistics, which can affect delivery…
– Potential language barriers and communication challenges when dealing with inter…
– Quality variations can occur if not all products meet the same stringent quality…
Product Details: The website https://www.nokcn-seals.com/video.html showcases the production process and various products of NNK-CN, including oil seals, O-rings, and other sealing solutions. It highlights the manufacturing process, quality control, and the range of products such as TC oil seals, power steering oil seals, and industrial seals.
Pros:
– Good wear resistance, tear resistance, and bending strength
– Excellent elasticity and high tension
– Moderate high temperature resistance (-30 degrees ~ 260 degrees)
– Large adjustable range of hardness (Shore 80A-95A)
– Oil and corrosion resistance, good solvent resistance, high mechanical strength…
– Excellent ozone resistance and aging resistance
– Non-toxic, in line with environmental protection requirements
Cons:
– No specific cons mentioned on the video page, but potential issues could include…
Frequently Asked Questions About Engine Oil Leak Seal Factories in China
What types of oil seals do Chinese manufacturers typically produce?
Chinese oil seal manufacturers produce a wide range of oil seals, including automobile oil seals, agricultural and construction machinery oil seals, wheel hub oil seals, valve stem seals, and precision rubber parts. These seals are designed for various applications such as engines, transmissions, axles, and other mechanical components.
What are the key features of oil seals made by Chinese manufacturers?
Oil seals from Chinese manufacturers are known for their high performance, extended equipment life, and enhanced productivity. They are made from materials like rubber or other elastomeric materials that can withstand high temperatures, pressures, and mechanical stress. These seals offer better sealing performance, less leakage, lower friction, and longer service life.
How do I ensure the quality of oil seals from Chinese factories?
To ensure the quality of oil seals, look for manufacturers that are ISO certified, such as ISO and IATF. These certifications indicate that the factory follows strict quality control standards. Additionally, check for customer reviews and ask for samples to test the seals before placing a large order.
Can Chinese oil seal manufacturers customize seals according to my specifications?
Yes, many Chinese oil seal manufacturers accept custom designs and OEM orders. They have advanced technology and equipment to develop and produce oil seals according to your specific requirements. This allows you to get seals that perfectly fit your needs and applications.
What is the typical minimum order quantity (MOQ) for oil seals from Chinese suppliers?
The minimum order quantity (MOQ) for oil seals from Chinese suppliers can vary, but it often ranges from 100 to pieces, depending on the manufacturer and the type of seal. Some suppliers may offer lower MOQs, while others may require larger orders. Always check the MOQ before placing an order.
If you are looking for more details, kindly visit Industrial Seals.