5 Minutes to Take You Through Combi Oil Seals.

--

Combination oil seals have come to the forefront of sealing components due to their durability and longevity. It is often used to seal agricultural machinery such as tractors. (Honglei(KDIK) shows you various COMBI oil seals and await in your inquiry.)

What is a Combination Oil Seal?

An oil seal consisting of two or more loose parts can be called a combination oil seal. Most common and simple combination oil seals are made of steel and oil resistant rubber. The two loose parts can complement or work together to make the most of the material’s own characteristics and improve sealing efficiency.

What are the characteristics of COMBI oil seals?

1. The COMBI oil seal consists of a common oil seal and a secondary seal, which mainly prevents the entry of external contaminants.

2. The COMBI oil seal has a spring at the lip of the seal.

3. COMBI oil seals have a dustproof lip.

4. COMBI oil seals are mainly used in environments with high contamination.

5. When subjected to large rotational or translational movements, it is preferable to use it instead of a cassette type combination seal.

6. COMBI oil seals have the distinctive features of combination oil seals: long life and resistance to wear.

7. COMBI oil seals are optimised in terms of the position of the sealing lips and dust lips, and are particularly resistant to contaminant ingress.

8. COMBI oil seals are often used in the driving part of moving parts of agricultural and industrial machinery.

Xingtai Honglei Seal Manufacturing Co., Ltd. registered trademark “KDIK” is senior manufacturer for global markets. We are professional oil seals factory with more than 18 years experience. Our main product lines include kinds of Automobile oil seal, Agricultural & Construction machinery oil seal, Precision Rubber Parts, O-rings and so on. Besides, we accept customer’s own designs and OEM design orders, always focus on Top quality products with competitive price and best service.

Modify: Mar. 22, 2023

Oil seal is the customary name of general seals, which is simply the seal of lubricating oil. It is used to seal grease (oil is a common liquid substance in the transmission system, also refers to the general meaning of liquid substances) mechanical components, it will drive parts in need of lubrication and output parts of isolation, so as not to let lubricant leakage. Static and dynamic seals (general reciprocating motion) are called oil seals with seals. The representative form of oil seal is TC oil seal, which is a double lip oil seal with self-tightening spring completely covered by rubber. Generally speaking, oil seal often refers to this TC skeleton oil seal.

Common materials for oil seals are: Nitrile rubber (NBR), fluorine rubber(FKM), silicone rubber, acrylic rubber, polyurethane, polytetrafluoroethylene and so on.

1. NBR

It has good heat resistance, wear resistance, resistance to various lubricants, greases, oil and gas mixtures, suitable for temperature - 30 - 120 degrees Celsius, but can no longer be used in phosphate hydraulic oil and gear oil containing extreme pressure additives, stable performance in gasoline and mineral oil with low aniline point.

2. Polyacrylate rubber (ACM)

Excellent oil and heat resistance, abrasion resistance, ozone resistance, ultraviolet radiation resistance, especially extreme pressure fluid containing lubricants, gear oil, motor oil, oil series hydraulic oil, etc., suitable for - 30 - 150 degrees Celsius range of work.

3. Fluororubber (FPM)

Aging resistance, heat resistance, oil resistance, almost applicable to all lubricants, fuel oils, gasoline, oil containing extreme pressure additives is not easy to harden, but cold resistance, high temperature wear resistance is poor, compression deformation is large, suitable for temperature - 20 ~ 250 degrees Celsius.

4. silicone rubber

It has outstanding resistance to high and low temperatures, can be used at 150 degrees Celsius for a long time without performance change, can be used at 200 degrees Celsius for 10,000 hours continuously, and can maintain its unique use flexibility, ozone resistance and weather resistance in the operating temperature range of - 70-260.

5. Teflon

It has outstanding chemical stability, thermal stability, friction reduction and self-lubrication. Its pyrolysis temperature is over 400. Therefore, it can work normally in the temperature range of - 200 - 300 degrees Celsius. Except for free fluorine and alkali metals, it has excellent corrosion resistance to chemicals, solvents, hydroxides and acids.

Nitrile butadiene rubber (NBR) and fluorine rubber (FBR) are widely used oil seals. The former has low cost, but its temperature resistance and sealing performance have been improved obviously, but the cost is higher, and it still has some bad common characteristics of ordinary rubber materials, such as poor wear resistance, short service life, especially sensitive to the eccentricity of the shaft, etc. Leakage phenomenon is still widespread. PTFE oil seal is a product with high technology content, which is the direction of oil seal development in the future.

Attention:

When choosing the material of oil seal, the compatibility of material to working medium, the adaptability to working temperature range and the ability of lip edge to follow the rotating axis at high speed must be considered. Generally, the temperature of lip edge is higher than that of working medium at 20-50 C. Attention should be paid to the selection of oil seal materials. The working range of oil seals is related to the materials used in oil seals: NBR, ACM, FPM and NBR.

Anywhere you look on the farm you will find seals of different designs. The purpose of any seal is to keep a fluid or semi-fluid such as grease from leaking out and equally as important, foreign material from entering.

The ability to isolate the component from external influences is just as imperative and possibly in some uses more so, than keeping the fluid inside.

This needs to be understood since most of us only consider a seal failed when there are visible signs of leakage.

A seal employed in a vacuum pump if weakened will introduce dirt and decrease the pump’s operation and useful life without any visible signs.

Many vacuum planters fall prey to a degraded seal that will impact the unit’s performance in the field since dust is highly abrasive.

Though commonly identified as a lip seal, it also goes by the name rotary or shaft seal. On an engine you will find lip seals in use at the front and rear of the crankshaft (one-piece rear main seal), in hydraulic pumps such as for the power steering, in a water pump and other areas.

On a vehicle or machine lip seals are used on the wheel bearings, drive axle bearings, transmission, air conditioner compressor, to name a few.

A lip seal is employed when there is a need to isolate two sides of a component within a rotating member.

Up until around the 1930s leather seals were common but since then lip seals have replaced that style. They have added reliability and improved protection from internal and external leakage.

The lip seal works by having an edge that rides on the rotating part while allowing a film of the fluid to reside between the lip and the shaft.

The confluence of the fluid film and the sealing material (usually some family of rubber or hybrid material such as PTFE) cause a hydrodynamic action.

In addition, a weak but effective pumping action takes place that further enhances the seal’s ability.

As the seal ages not only does the lip that contacts the shaft wears but the material it is made from becomes less pliable, brittle and from thermal excursions, may have the tendency to bow away from the rotating member. When any of this occurs, the seal becomes challenged and can leak both ways.

Important considerations

When changing a lip seal, it is imperative that it is made from the proper material for the fluid that is going to be isolated along with the rpm of the shaft; the higher the speed the greater the heat generated at the contact point.

Also, many lip seals are directional in nature, especially with but not limited to those used in engines. The seal will usually have a small arrow on it to identify the rotation required for the lip to make contact on the shaft. If installed in the wrong rotation the seal will leak immediately.

The cavity the seal resides in needs to be extremely clean and free of any rust or corrosion. If the seal is even minutely cocked it will not function.

The shaft that runs through it must also be clean and smooth and possess no axial grooves. If there are any grooves they have the ability to work like an auger and pull fluid past the lip.

It is important that when the lip seal is being pressed or tapped into place that it is not damaged. Though there are dedicated seal installers that should be used, many improvise and use a socket from a ratchet set. If common sense is employed and the seal and socket can interface properly, it is an acceptable procedure.

If you are careless or the fit is compromised, then the repair may be for naught.

A lip seal installation kit with a variety of proper sizes may be a worthwhile investment.

Always lightly lubricate the cavity the seal will fit into before attempting installation.

The common mistakes made when servicing any lip seal are not lubricating the shaft so that the lip does not run dry on the rotating member before it can pull a film of liquid; reusing even a fairly new lip seal; buying a cheap imported seal that has the proper O.D. but is made from the wrong material.

Most lip seals are designed that once removed not to be put back into service. This is especially true on a component that spins at high speed and is exposed to high temperatures. You may get lucky every now and then, but do not make it a habit.

If you follow these simple steps and invest in the proper name brand lip seals, you will be rewarded with a job well done and an effective and long-lasting repair.