Curvic coupling



Curvic couplings are applied to aircraft parts, gas turbines, industrial robots, advanced machine tools and indexing tables.



-Various sizes up to 360!

number of teeth in the range of 6-720T, standardized outer diameter in the range of ¥õ50~¥õ1500, customizable OD/number of teeth/width to satisfy various purposes and applications.

-Tough rigidity

Use of premium steel (chrome molybdenum) and heat treatment at high temperature ensures high crashworthiness and rigidity.

-High restitution and indexing

Guaranteed with the restitution within ¡¾5.0 seconds for the same tooth coupling points (the Accuracy grade). 4-division indexing accuracy of ¡¾3.0 seconds in case of 90¢ª indexing (the Super Accuracy grade).

-Long-term Product Warranty

The curvic couplings of DLC come with a long term product warranty thanks to the strict total number quality inspection throughout the whole processes.


Teeth viewed at the outside diameter

Curvic coupling

Shape of Tooth

Curvic coupling

Product Classification

Type Out
M Curvic coupling It is called the ¡®mini curvic¡¯. It attaches importance on the degree of stability which is normally above 70% in this model. Small precision instruments are applied to exchange turret and WORK.
¡¤ Type Number: Written in the order of ¡®number of teeth¡¯, ¡®outside diameter¡¯ and ¡®inside diameter¡¯
S Curvic coupling As the most common type, this is used in the index table at machining centers where high level of stability and accuracy is required; NC lathe turrets where stability is required; and in pallet changer where compatibility is required.
¡¤ Type Number: Written in the order of ¡®number of teeth¡¯, ¡®outside diameter¡¯ and ¡®inside diameter¡¯.
S Curvic coupling It is also called the ¡®large curvic¡¯. It is used at large sized machining centers or used to a transfer machine to determine the division positions. It has a number of ¡®set exchanges¡¯ and it is rare to use only one side.

¡¤ Type Number: Written in the order of ¡®number of teeth¡¯, ¡®outside diameter¡¯ and ¡®inside diameter¡¯.
W Curvic coupling It is called the ¡®heterogeneous profile curvic¡¯ The inside diameter and the clamp cylinder diameter can be enlarged. It is used as a large turret.
¡¤Type Number: Written in the order of ¡®number of teeth¡¯-¡®tooth outside diameter¡¯, ¡®tooth inside diameter¡¯-¡®maximum outside diameter¡¯.
S Curvic coupling It is used for a detailed clutch that delivers rotational motion, or in the case where clamp force is limited more than by the curvic coupling 30¨¬ which has the special teeth with the input angle of 15¨¬. It has similar characteristics of that of 30¨¬.

¡¤ Type Number: Written in the order of ¡®number of teeth¡¯, ¡®outside diameter¡¯ and ¡®inside diameter¡¯
V Curvic coupling It is called the ¡®3-PIECE CURVIC¡¯. It is used to rotate a heavy ¡®WORK¡¯ without rising.
¡®Set exchange¡¯ is default, and it is less compatible than 2PCC.

¡¤Type Number: Written in the order of ¡®number of teeth¡¯, ¡®outside diameter¡¯ and ¡®inside diameter¡¯.


Curvic coupling

Standard Quality Control Procedure

ITEM Accuracy Super
Tooth Contact
Contact to the number of teeth
More than 80% More than 90%

The status of teeth being mated to the curvic coupling (the gauge for testing) is checked. The standard contact length of the teeth is above 50% of the teeth width at the center. Throughout the whole teeth, two adjacent teeth should not be disconnected in a row. More than 80% of the teeth surface should be contacted evenly.

Contact to the face width
More than 50% More than 50%
Tooth Coupling Run-out at the face top 0.02 0.01 The status of ¡®run-out¡¯ is checked by the dial gauge by light mating the unit with the master curvic coupling (the gauge for testing).
Run-out at OD 0.02 0.01
Indexing Accuracy 5" 3"

The max cumulative error at 4-division

Coupling Thickness ±0.10 ±0.05 The combined thickness of the èê (convex) and the ôÈ (concave) teeth when mated.

Strength Formula for Curvic Coupling

Curvic coupling

Division Accuracy

Curvic coupling

As the coupling obtains a significant level of clamp force and hardness, it is optimally used for index tables at machining centers for heavy cuttings and in torque transfers. However the allowable load differs to the size of the curvic coupling in use. As the allowable cutting load, torque and clamp force determine the type/size of the curvic coupling, please refer to the formula to select the right one.