CAT PRECISION SEALS®

Seal Group Size (Class) Options
Seal Group Size (Class) Options. Duo-ConeTM seals are classified by toric cross sections ranging from4.30 to 16.00 mm (0.170 to 0.630 in). Larger section torics can accommodate greater amounts of systemdeflection and are less sensitive to end play and environmental effects, but occupy more space in thedesign.
HDDF seals incorporate a rectangular load ring, known as a Belleville Washer (BW), instead of a toric.
HDDF seals occupy less axial space in a system and have simpler housing dimensions, but occupy moreradial space than a Duo-Cone design and are more sensitive to system deflection and end play.
The table shown below gives a brief summary of available design options.
ClassABCDLKToric Size (mm)
4.30
6.22
9.47
12.70
16.00
HDDF Load Ring

Class A – 4.30 mm (0.17 in) Toric Cross Section
Duo-Cone seals with a 4.30 mm crosssection toric ring are used only in small
diameter applications with extreme axial
and radial constraints. Seals of this type havevery little end play capability and are extremely
sensitive to system deflections. This type of seal
is not recommended for most applications.
Class B – 6.22 mm (0.24 in) Toric Cross Section
Duo-Cone seals with 6.22 mm crosssection toric rings (104.67 to 222.5 mm[4.12 to 8.76 in]) are typically used insmall axle or rock bit applications.
They are used where sealing is needed in
extreme environments, but where there isinsufficient space to put a larger cross section
Duo-Cone seal. While these seals do have someend play capability, they have less than sealclasses with larger cross section torics.

Seal Ramp Angle (°)
20158/15/20
8/15/2015
Square Bore

Housing Ramp Angle (°)
1510101010
Square BoreClass C – 9.47 mm (0.37 in) Toric Cross Section
9.47 mm cross-section Duo-Cone seals
range in diameter from 82.5 to 199.0 mm(3.248 to 7.835 in). They are typically usedin moving undercarriages for trackedmachines. These seals have good end
play capability and are available with 8°, 15°, and20° seal ramps to serve different operating
environments.
Class D – 12.70 mm (0.50 in) Toric Cross Section
The Class D Duo-Cone seal is very
common in axle, wheel and final
drive applications in constructionand earth moving equipment. Seals
are available from 171.7 to 865.0 mm(6.760 to 34.055 in) in diameter. Theseseals have very good end play capability. Seals
are available with both 8° and 15° seal ramps.

© 2014 Caterpillar • All Rights Reserved • Printed in USA
CAT, CATERPILLAR, BUILT FOR IT, their respective logos, “Caterpillar Yellow,” the “Power Edge”trade dress as well as
corporate and product identity used herein, are trademarks of Caterpillar and may not be used without permission.

Seal Group Size (Class) Options
Class L – 16.00 mm (0.63 in) Toric Cross Section
Currently, the largest crosssection toric ring offered byCat Seals, the Class L sealconsists of a 16.00 mm (0.63in) cross section toric and isspecified for only the largestof sealing applications. CatSeals offers a single size of
939.8 mm (37.000 in) in diameter, which has very
good end play capability, but requires thelargest sealing cavity design in the Duo-Coneseal family.

Class K – Heavy Duty Dual Face Belleville Washer
The HDDF seal requires a squarebore housing design and a
Belleville washer load ring toprovide loads to the seal faces.
This seal design is available insizes ranging from 61.6 to 780.2
mm (2.425 to 30.716 in) indiameter. While fit and form are different,
functionally is completely interchangeable with aconventional Duo-Cone seal at the design stage.

© 2014 Caterpillar • All Rights Reserved • Printed in USA
CAT, CATERPILLAR, BUILT FOR IT, their respective logos, “Caterpillar Yellow,” the “Power Edge”trade dress as well as
corporate and product identity used herein, are trademarks of Caterpillar and may not be used without permission.