KCW

Dimensions

Materials

Metal cage

The table below shows the materials that we can offer for metal cages.

Application	Material	Standard	Characteristics
Metal cage	Non-alloy standard steel	AISI 1010 (DIN 1624)	Cold rolled steel
Metal cage	Nickel chrome steel	AISI 304 (DIN 1.4301 - V2A)	Standard stainless steel
Metal cage	Chrome-nickel-molybdenum steel	AISI 316 (DIN 1.4401 - V4A)	Stainless steel highly resistant to corrosion

Rubbers

ACM (Polyacrylate)

Polymers containing ethyl acrylate (or butyl acrylate) have a small amount of monomer, which is necessary for cross-linking; ACM is a material with better heat resistance than NBR. It is often used for automatic gearboxes.

Chemical resistance	Mineral oils (motor oils, gear box oils, ATF oils) Atmospheric and ozone agents
Compatibility issue	Glycol-based brake fluids (Dot 3 & 4) Aromatic and chlorinated hydrocarbons Water and steam Acids, alkalis and amines
Temperature range	-25°C to + 150°C (short-term peak at +160°C) -35°C / +150°C with particular ACMs

AEM (ethylene acrylate rubber)

As a methyl acrylate and ethylene copolymer, AEM is considered to be more resistant to heat than ACM. Its characteristics make it an intermediary between ACM and FKM.

Chemical resistance	Cooling fluids Aggressive mineral oils Atmospheric agents Water
Compatibility issue	Aromatic solvents Strong acids Brake fluids Gearbox oils ATF oils
Temperature range	- 40°C to + 150°C

CR (Polychloroprene)

This CR-based rubber is used in the refrigeration industry and for ventilation systems. This chloroprene was the first synthetic rubber to be developed and marketed.

Chemical resistance	Paraffinic mineral oils Silicone oils and greases Water and water-based solvents for use at low temperatures Refrigerant fluids Ammoniac Carbon dioxide Atmospheric and ozone agents
Limited chemical resistance	Naphthenic mineral oils Aliphatic hydrocarbons (propane, butane, petroleum) Glycol-based brake fluids
Compatibility issue	Aromatic hydrocarbons (benzene) Chlorinated hydrocarbons (trichlorethylene) Polar solvents (ketone, acetone, acetic acid, ethylene-ester)
Temperature range	-40°C / +100°C (short-term peak at +120°C)

EPDM (Ethylene Propylene Diene Monomer rubber)

As an Ethylene Propylene Diene Monomer copolymer, EPDM is commonly used for hot water taps, cooling systems, brake systems, dishwashers and washing machines.

Chemical resistance	Hot water and steam up to +150°C Glycol-based brake fluids (Dot 3 & 4) and silicone-based brake fluids (Dot 5) Organic and inorganic acids Cleaning agents, sodium and potassium alkalis Hydraulic fluids (HFD-R) Silicone oils and greases Polar solvents (alcohols, ketones and esters) Atmospheric and ozone agents
Compatibility issue	Mineral oils and greases Hydrocarbons Low impermeability to gas
Temperature range	-45°C / +150°C (short-term peak at +175°C)

FFKM (perfluorinated rubber)

FFKM has the best characteristics for resistance to high temperatures, with an excellent chemical inertia. This FKM-based rubber is very often used for high-temperature hydraulic and pneumatic systems, industrial valves, injection/fuel systems, motor seals and high-vacuum systems.

Chemical resistance	Aliphatic and aromatic hydrocarbons Polar solvents (ketones, esters and ethers) Organic and inorganic acids Water and steam High-vacuum system
Compatibility issue	Coolants (R11, R12, R13, R113, R114, etc.) PFPE
Temperature range	-15°C/+320°C

FKM (fluorinated rubber)

Depending on their structure and fluorine content, the chemical resistance and resistance to the cold in fluororubbers can vary. This FKM-based rubber is very often used for high-temperature hydraulics and pneumatics, for industrial valves, injection/fuel systems, motor seals and high-vacuum systems.

Chemical resistance	Mineral oils and greases, ASTM n°1, IRM 902 and IRM 903 oils. Fire-resistant liquids (HFD) Silicone oils and greases Mineral and vegetable oils and greases Aliphatic hydrocarbons (propane, butane, petroleum) Aromatic hydrocarbons (benzene, toluene) Chlorinated hydrocarbons (trichlorethylene) Fuel (including high alcohol content) Atmospheric and ozone agents
Compatibility issue	Glycol-based brake fluids Ammonia gas Organic acids with a low molecular weight (formic and acetic acids)
Temperature range	-20°C / +200°C (short-term peak at +230°C) -40°C / +200°C with particular FKMs

FVMQ (fluorosilicone rubber)

The FVMQ has mechanical and physical properties that are very similar to those of the VMQ. However, the FVMQ offers better resistance to fuels and mineral oils. However, resistance to hot air is not as good as that of the VMQ.

Chemical resistance	Aromatic mineral oils (IRM 903 oil) Fuels Aromatic hydrocarbons with low molecular weights (benzene, toluene)
Temperature range	-70°C/+175°C

HNBR (Hydrogenated Nitrile Butadiene Rubber)

This HNBR-based rubber is obtained through selective hydrogenation of the NBR's butadiene groups. It is commonly used for power-assisted steering and for air conditioning.

Chemical resistance	Aliphatic hydrocarbons Mineral and vegetable oils and greases Fire-resistant fluids (HFA, HFB and HFC) Diluted acids, saline solutions and bases for operation at an average temperature Water and steam up to +150°C Atmospheric and ozone agents
Compatibility issue	Chlorinated hydrocarbons Polar solvents (ketones, esters and ethers) Strong acids
Temperature range	-30°C / +150°C (short-term peak at +160°C) -40°C / +150°C with particular HNBRs

NBR (Nitrile Butadiene Rubber)

Nitrile rubber (NBR) is the general term for acrylonitrile-butadiene copolymer. The ACN content can vary between 18% and 50%. While the acrylonitrile content is important, the resistance to oil and fuel is more so. Conversely, the elasticity and compression set are not as good. The NBR has good mechanical properties and good wear resistance. However, its resistance to atmospheric agents and the ozone is relatively low.

Chemical resistance	Aliphatic hydrocarbons (propane, butane, petroleum, diesel fuel) Mineral oils and greases Fire-resistant fluids (HFA, HFB and HFC) Diluted acids, low-temperature alkaline and saline solutions Water (up to +100°C max)
Compatibility issue	Fuels with high aromatic content Aromatic hydrocarbons (benzene) Chlorinated hydrocarbons (trichlorethylene) Polar solvents (ketone, acetone, acetic acid, ethylene-ester) Strong acids Glycol-based brake fluids Atmospheric and ozone agents
Temperature range	-30°C / +100°C (short-term peak at +120°C) -40°C / +100°C with particular NBRs

VMQ (silicone rubber: methyl vinyl polysiloxane)

This FVMQ-based rubber is very often used in fuel systems.

Chemical resistance	Animal and vegetable oils and greases Water for operation at an average temperature Diluted saline solutions Atmospheric and ozone agents
Compatibility issue	Superheated steam up to +120°C Chlorinated hydrocarbons with a low molecular weight (trichlorethylene) Aromatic hydrocarbons (benzene, toluene)
Temperature range	-60°C / +200°C (short-term peak at +230°C)

The table below gives an overview of the physical, chemical and mechanical characteristics for each of the materials.

Characteristics/Materials	ACM	AEM	CR	EPDM	FFKM	FKM	FVMQ	HNBR	NBR	VMQ
Abrasion resistant	2	3	2	2	4	2	4	2	2	4
Resistance to acids	4	3	2	2	1	1	3	1	3	3
Chemical resistance	4	2	2	1	1	1	1	2	2	2
Resistance to cold	4	2	2	2	3	4	2	2	2	2
Dynamic properties	3	3	3	2	3	2	4	1	2	4
Electrical properties	3	3	3	2	1	4	1	3	3	1
Flame resistant	4	4	2	4	1	1	2	4	4	3
Heat resistant	1	1	2	2	1	1	1	1	2	1
Sealing water	1	1	2	2	2	2	4	2	2	4
Oil resistant	1	3	2	4	1	1	2	1	1	2
Ozone resistant	1	1	2	1	1	1	1	2	4	1
Tearing resistant	2	3	3	1	4	3	4	2	2	4
Traction resistant	3	2	2	1	2	1	3	1	2	4
Water/vapour resistant	4	4	3	1	2	3	3	1	2	3
Resistance to atmospheric agents	1	1	1	1	1	1	1	2	3	1

1. Excellent properties 2. Good properties 3. Average properties 4. Poor properties

Chemical compatibility

A "Chemical compatibility guide" catalogue can be downloaded from the Documentation section. You can also use our online "Chemical compatibility" tool free of charge.

These two tools give you the option of measuring the behaviour of our materials that come into contact with the majority of existing fluids. The data displayed is the result of rigorous testing of the ambient temperature and in consultation with previous publications. Test results are not fully representative due to the specific features of your application. The tests performed actually do not consider additives and impurities that may exist under the actual conditions of use, nor the potential elevation of temperatures. Other parameters can also alter the behaviour of our materials, such as the hardness, persistence, abrasion, etc. We therefore recommend performing your own tests to verify the compatibility of our materials according to your specific application. Our technical team can provide you with any additional information.

Conditions for use

Speed

The table below indicates the relationships between the linear speed, the rotation speed and the recommended material.

Linear speed calculation:

s (m/s) = [Ø shaft (mm) x speed (rpm) x π] / 60,000

Pressure

Standard shaft seals with a primary sealing lip and no spring are used only in unpressurised environments.

We recommend using shaft seals with springs for use in pressurised environments between 0.02 and 0.05 MPa (max).

For even higher pressures, we recommend using high-pressure SCHP - TCHP shaft seals which, because of their specific design (shorter sealing lip, thicker rubber membrane, metal cage closer to the shaft), can support pressures of up to 1.0 MPa with speeds reduced to 0.3 m/s.

Temperature

The table below indicates the temperature limits, depending on the materials and fluids used.

Media		Maximum temperature, depending on the materials
		ACM	AEM	EPDM	FKM	HNBR	NBR	VMQ
Mineral oils	Oils for motors	+130°C	+130°C	-	+170°C	+130°C	+100°C	+150°C
	Oils for gearboxes	+120°C	+130°C	-	+150°C	+110°C	+80°C	+130°C
	Oils for hypoid gears	+120°C	+130°C	-	+150°C	+110°C	+80°C	-
	ATF oils	+120°C	+130°C	-	+170°C	+130°C	+100°C	-
	Hydraulic oils	+120°C	+130°C		+150°C	+130°C	+90°C	-
	Greases	-	+130°C	-	-	+100°C	+90°C	-
Fire-resistant fluids	HFA group - Emulsion with more than 80% water	-	-	-	-	+70°C	+70°C	+60°C
	HFB group - Opposite solution (water in oil)	-	-	-	-	+70°C	+70°C	+60°C
	HFC group - Polymer aqueous solution	-	-	+60°C	-	+70°C	+70°C	-
	HFD group - Water-free synthetic fluids	-	-	-	+150°C	-	-	-
Other fluids	EL + L heating oil	-	-	-	-	+100°C	+90°C	-
	Air	+150°C	+150°C	+150°C	+200°C	+130°C	+90°C	+200°C
	Water	-	-	+150°C	+100°C	+100°C	+90°C	-
	Water for washing	-	-	+130°C	+100°C	+100°C	+100°C	-
Temperature range	Min.	-25°C	-40°C	-45°C	-20°C	-30°C	-30°C	-60°C
	Max.	+150°C	+150°C	+150°C	+200°C	+150°C	+100°C	+200°C

The sealing lip of the shaft seal endures a higher temperature due to shaft rotation, and the significant pressure and friction on the mechanical parts. Good lubrication is therefore necessary to allow for a better release of heat and thus limits the temperature rise in the parts subjected to friction.

By definition, the temperature at the edge of the seal is raised when the rotation speed (and thus the linear speed) as well as the shaft diameter increases. The graph below gives an overview of the increase in temperature (in °C) at the point of contact on the sealing lip.

Fluids

Greases

Greases are generally applied to bearings etc. and require specific adaptation to provide favourable operating conditions for the shaft seal. To prevent the lip of the seal from sustaining more significant pressures than planned, we recommend positioning the lip seal on one side of the bearing in such a way so that the lip is not prematurely destroyed. We also recommend reducing the rotation speed by 50% when lubricated, to ensure that less heat escapes during friction.

Seal design

Tolerance for the outside diameter of the seal (ØD)

The table below indicates the pre-tightening for shaft seals on the housing diameter according to standard ISO 6194-1.

Bore diameter ØD1 (mm)	Tolerances on the outside diameter ØD of the ring			Roundness tolerance
	Apparent metal cage	Rubber coating	Coating with grooves	Apparent metal cage	Rubber coating
ØD1 ≤ 50.0	+0.10 / +0.20	+0.15 / +0.30	+0.20 / +0.40	0.18	0.25
50.0 < ØD1 ≤ 80.0	+0.13 / +0.23	+0.20 / +0.35	+0.25 / +0.45	0.25	0.35
80.0 < ØD1 ≤ 120.0	+0.15 / +0.25	+0.20 / +0.35	+0.25 / +0.45	0.30	0.50
120.0 < ØD1 ≤ 180.0	+0.18 / +0.28	+0.25 / +0.45	+0.30 / +0.55	0.40	0.65
180.0 < ØD1 ≤ 300.0	+0.20 / +0.30	+0.25 / +0.45	+0.30 / +0.55	0.25% of ØD	0.80
300.0 < ØD1 ≤ 500.0	+0.23 / +0.35	+0.30 / +0.55	+0.35 / +0.65	0.25% of ØD	1.00
500.0 < ØD1 ≤ 630.0	+0.23 / +0.35	+0.35 / +0.65	+0.40 / +0.75	-	-
630.0 < ØD1 ≤ 800.0	+0.28 / +0.43	+0.40 / +0.75	+0.45 / +0.85	-	-

Tolerance for the inside diameter of the seal (Ød)

Free and without constraint, the inside diameter of the sealing lip is always smaller than the diameter of the shaft. The pre-tightening or interference denotes the difference between these two values. Depending on the shaft diameter, the diameter of the sealing lip is generally considered to be less, between 0.8 and 3.5 mm.

Shaft design

Shaft material

Suitable materials are:

• ordinary C35 and C45 steels used in mechanical construction
• 1.4300 and 1.4112 stainless steels for sealing water
• sprayed carbide coatings
• graphite
• malleable cast iron
• materials with a CVD and PVD coating

Not appropriate:

• chrome coatings solidified through non-uniform wear
• plastic materials resulting from low thermal conductivity, which can lead to a disturbance in the transport of heat, an increase in temperature in friction areas with the shaft seal, as well as a potential softening

Shaft hardness

Shaft hardness will depend on the linear speed (in m/s) and the level of pollution.

Rotation speed	Hardness in HRC
s ≤ 4.0 m/s	45 HRC
4.0 < s ≤ 10.0 m/s	55 HRC
s > 10.0 m/s	60 HRC

Surface roughness

The recommendations below must be considered for the quality of the shaft surface area.

Standard conditions:

• Ra = 0.2 to 0.8 µm and 0.1 for demanding applications
• Rz = 1.0 to 4.0 µm
• Rmax ≤ 6.3 µm

Shaft tolerance

The shaft must have a tolerance of h11, in line with standard ISO 286-2

Shaft diameter Ød1 (mm)	Tolerance h11 (mm)
Ød1 ≤ 3.0	-0.060 / 0
3.0 < Ød1 ≤ 6.0	-0.075 / 0
6.0 < Ød1 ≤ 10.0	-0.090 / 0
10.0 < Ød1 ≤ 18.0	-0.110 / 0
18.0 < Ød1 ≤ 30.0	-0.130 / 0
30.0 < Ød1 ≤ 50.0	-0.160 / 0
50.0 < Ød1 ≤ 80.0	-0.190 / 0
80.0 < Ød1 ≤ 120.0	-0.220 / 0
120.0 < Ød1 ≤ 180.0	-0.250 / 0
180.0 < Ød1 ≤ 250.0	-0.290 / 0
250.0 < Ød1 ≤ 315.0	-0.320 / 0
315.0 < Ød1 ≤ 400.0	-0.360 / 0
400.0 < Ød1 ≤ 500.0	-0.400 / 0

Chamfer and radius

You are strongly advised to install a chamfer on the shaft so as not to alter the primary sealing sealing lip of the shaft seal during assembly. Please refer to the table below.

Shaft diameter Ød1 (mm)	Chamfer diameter Ød3 (mm)	Radius R (mm)
Ød1 ≤ 10.0	Ød1 - 1.50	2.00
10.0 < Ød1 ≤ 20.0	Ød1 - 2.00	2.00
20.0 < Ød1 ≤ 30.0	Ød1 - 2.50	3.00
30.0 < Ød1 ≤ 40.0	Ød1 - 3.00	3.00
40.0 < Ød1 ≤ 50.0	Ød1 - 3.50	4.00
50.0 < Ød1 ≤ 70.0	Ød1 - 4.00	4.00
70.0 < Ød1 ≤ 95.0	Ød1 - 4.50	5.00
95.0 < Ød1 ≤ 130.0	Ød1 - 5.50	6.00
130.0 < Ød1 ≤ 240.0	Ød1 - 7.00	8.00
240.0 < Ød1 ≤ 500.0	Ød1 - 11.00	12.00

Shaft run out and eccentricity

The shaft run out is a deviation between the current shaft axis and the theoretical rotation axis. It is important to reduce the shaft run out as much as possible by positioning the shaft seal as close as possible to the bearing.

The shaft and housing must be assembled centred on one another in order to remove any unilateral radial load at the sealing lip of the ring.

Shaft machining

Correct shaft machining is essential to the proper operation of the sealing system.

• Plunge grinding: preferred machining method that ensures the absence of striations on the shaft (0 +/- 0.05°)
• Turning: suitable for shafts used with a unidirectional sense of rotation

Machining guidelines for surface adjustments

Parameters	Requirements
Speed of the part to be machined	30 to 300 rpm
Wheel speed	1500 to 1700 rpm
Surfacing feed	< 0.02 mm/turn
Dressing tool	multi-grain dressing diamond, single drain dressing diamond
Grinding rate feed	approximately 0.02 mm
Spark duration	full spark, min. 30 secs
Passing depth	> Rmax of the old machining operation
Eccentricity of the tool and part to be machined	the best possible

Housing design

Surface roughness

The recommendations below must be considered for the quality of the housing surface area.

Standard conditions for shaft seals with a rubber coating:

• Ra = 1.6 to 6.3 µm
• Rz = 10.0 to 25.0 µm
• Rmax ≤ 25.0 µm

Tolerance of the bore diameter of the housing

The bore diameter of the housing must have a tolerance of H8, in line with standard ISO 286-2

Bore diameter ØD1 (mm)	Tolerance H8 (mm)
3.0 < ØD1 ≤ 6.0	0 / +0.018
6.0 < ØD1 ≤ 10.0	0 / +0.022
10.0 < ØD1 ≤ 18.0	0 / +0.027
18.0 < ØD1 ≤ 30.0	0 / +0.033
30.0 < ØD1 ≤ 50.0	0 / +0.039
50.0 < ØD1 ≤ 80.0	0 / +0.046
80.0 < ØD1 ≤ 120.0	0 / +0.054
120.0 < ØD1 ≤ 180.0	0 / +0.063
180.0 < ØD1 ≤ 250.0	0 / +0.072
250.0 < ØD1 ≤ 315.0	0 / +0.081
315.0 < ØD1 ≤ 400.0	0 / +0.089
400.0 < ØD1 ≤ 500.0	0 / +0.097
500.0 < ØD1 ≤ 630.0	0 / +0.110

Groove width dimensions

The table below provides information on the width of the groove and the recommended radius.

Height H1	Width		Radius Max R2
	L2min (H1 x 0.85)	L1min (H1 x +0.3)
7.00	5.95	7.30	0.50
8.00	6.80	8.30
10.00	8.50	10.30
12.00	10.30	12.30	0.70
15.00	12.75	15.30
20.00	17.00	20.30