What is motor seal products and Why Do We Use Them?

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

1. What are oil seals?

A wide range of sealing devices are used in various machines.
Sealing devices serve the following functions:

• Prevent leakage of sealed lubricant from inside
• Prevent entry of dust and foreign matter (dirt, water, metal powder, etc.) from outside

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

2. Oil seal structure and functions

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　

3. Seal types and numbering system

1) Common seal types and their features

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 6194-1 and JIS B 2402-1.
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 6194-1 1)

JIS B 2402-1 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

2) Special seal types and their features

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

3) Seal numbering system

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.

4. Example of the applications of seals

Oil seals are used in a great many machines.

1) Oil seals for cars

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

2) Oil seals for steel production equipment

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

5. Conclusion

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:

THE RACER’S CHOICE

PERMANENTLY SEALS

• Leaking Head Gaskets
• Cracked Heads and Blocks in Aluminum or Cast Iron
• Coats the Engine and Prevents Formation of Rust and Salt Water Corrosion
• Seals Porous Castings in the Cooling System
• Stops Coolants Leaks
• Promotes Heat Dissipation for Added Power

Add to Radiator Only After Removing Anti-Freeze.

Ceramic Motor Seal a ceramic engine block sealer is a product to coat all areas of the inside of your engine cooling system. It’s important to start with a clean and free of debris system. For this reason it is recommended that you use Irontite Thoro-Flush to fully clean your cooling system before treating with Ceramic Motor Seal.

Be sure to read and follow all the instructions carefully. And once you have completed the application of Ceramic Motor Seal we recommend using Irontite All Weather Seal with your normal Anti-Freeze mixture. All Weather Seal will prevent any future leaks.

INSTRUCTIONS

Warning: Ceramic Seal is not compatible with anti-freeze. All anti-freeze must be removed before using. Use a flush to “clean” your cooling system and after flushing, rinse your system with water at least once.

One bottle treats up to 6 gallons. HD trucks may require additional bottles and smaller systems may use less than the entire bottle.

CAUTION: ALWAYS ALLOW ENGINE TO COOL so radiator cap or top radiator hose can be removed safely.

** Raw Ceramic Seal will damage painted and chrome surfaces permanently. **

1. Drain and flush coolant system. (We recommend Industrial-Strength .) Rinse system with water at least once.
2. If vehicle does not have a pressurized radiator cap, remove top radiator hose and fill water and product directly into the radiator from the top hose.
3. Shake Bottle well. If bottle has sediment in the bottom be sure to get it mixed up before adding to your system. (no hard lumps) If there is more than ¾” of sediment that will not mix, do not use.
4. Fill coolant system with clean water and the appropriate amount of Ceramic Seal based on your cooling system capacity. (1 bottle = 6 gallon system capacity. 3 gallon system capacity = ½ bottle)
5. Ceramic Seal ** WILL PERMINANTLY ** stain paint and/or chrome surfaces. Wipe any excess from cap and radiator neck.
6. Replace radiator cap or re-attach radiator hose and tighten hose clamp.
7. Completely fill system with water, including overflow tank. Run engine and check level again.
8. Run engine on fast idle for a minimum of 1 hour, or vehicle may be driven up to two days. Then drain completely and rinse/flush with water. The longer you run the thicker the seal coat will be.
9. Leave coolant system open and empty for 12 hours minimum to let Ceramic Seal air dry and cure. A basic hand held hair dryer can be used to speed up and/or improve drying process.
10. After 12 hours or more of air drying, fill with normal coolant mixture.
11. We recommend adding Irontite All Weather Seal, along with coolant mixture to prevent further leaks.

FOR INDUSTRIAL USE ONLY

KEEP OUT OF REACH OF CHILDREN

Caution: Avoid Skin or Eye contact.
First Aid: Eyes & Skin - Flush for 15 minutes with cool water. Internal? Take 3-4 glasses of water or milk. Do NOT induce vomiting. Call a physician at once.

SELLADOR DE CERAMICA IRONTITE
Advertencia: El Sellador de Ceramica no es compatible con el anticongelante. El anticongelante se tiene que vaciar antes de usar este sellador.
Un bote alcanza para 6 galones. Los camiones heavy duty requieren varios botes.
PRECAUCION: DEJE QUE EL MOTOR SE ENFRIE y remueva la tapa del radiador o la manguera superior con cuidado.

1. Drene y enjuague el radiador y las mangueras. (Recomendamos usar el Irontite Thoro -Flush.)
2. Si el vehiculo no tiene tapon de radiador, quite la manguera superior del radiador y vacie el contenido del bote directamente en la manguera junto con el agua.
3. Agite bien el bote.
4. Rellene el radiador con agua limpia y el Sellador Ceramico.
5. El Sellador Ceramico puede manchar las superficies pintadas o cromadas. Limpie los excesos de sellador del tapon y la manguera.
6. Ponga el tapon o la manguera del radiador y asegurelas.
7. Encienda el vehiculo y rellene el deposito de reserva de agua.
8. Encienda el motor y dejelo asi durante una hora minimo, o bien use el auto durante 2 dias. Despues drene completamente el radiador.
9. Deje el radiador abierto y vacio por 12 horas minimo para dejar que el Sellador de Ceramica se seque y se cure.
10. Despues de 12 horas rellene con anticongelnte.
11. Recomendamos agregar el Sellador Para Todo Clima Irontite al anticongelante para prevenir fugas a futuro y lubricar la bomba de agua.

UNICAMENTE PARA USO INDUSTRIAL MANTENGASE FUERA DEL ALCANCE DE LOS NIÑOS
Precaucion: Evite el contacto con los ojos y la piel.
Precaucion: Evite el contacto con los ojos y la piel. Primeros auxilios: Ojos y piel: Enjuague por 15 minutos con agua fresca. Si se ingiere tome de 3 a 4 vasos de agua o leche. No induzca el vomito. Llame a su medico inmediatamente.

** INSTRUCTIONS WHEN USING IRONTITE CIRCULATOR**

As part of it’s overall crack repair process, Irontite recommends Ceramic Seal. When properly applied, Ceramic Seal leaves a fine ceramic coating on the inside of the casting, closing porosity and the inside of minor cracks.

In conjunction with crack repair work, Ceramic Seal is applied to the casting after the repair process is complete to give the repair a finishing touch and the added assurance the crack is sealed.

1. The head or block is remounted on the pressure tester and the water ports are sealed so the casting can be pressurized.

2. After pressurizing the head or block and confirming the high quality of the Irontite repair job, secure the outlet and return hoses on a circulator to opposite ends of the head or block.

3. Activate the circulator and circulate Irontite Ceramic Seal through the casting at the temperature supplied by the circulator.

4. After circulating the Ceramic Seal for a period of 15-30 minutes, close off both the outlet valve and the return valve.

5. Depress the air pressure button, holding it down for a few seconds and then releasing it. This pressure forces the ceramic seal in the casting into any cracks or porosity in the interior of the casting.

6. Turn the head over, open the circulator return valve and press the air pressure button for only a few seconds. This will force the remaining liquid Ceramic Seal back into the circulator tank.

7. Remove the casting and set it to one side allowing the Ceramic Seal in the interior of the casting to cure.

After a period of time, the Ceramic Seal will cure on the inside of the casting and will serve as an additional seal to the crack. The time required for the seal to set or cure will vary depending on temperature and humidity.

NOTE: When using Irontite Ceramic Seal, it is MANDATORY that the cooling system be cleaned first to make certain that any anti-freeze or coolant is flushed out and the system is clean. Ceramic Seal IS NOT COMPATIBLE WITH ANTI-FREEZE OR COOLANT. Combining them in the cooling system will clog the cooling system.