Curvic Coupling

Curvic coupling

Curvic couplings are the core part for joining shafts, which are widely used in CNC lathe turrets, machine tools, robots, gas turbines, and high-tech products such as aircraft.

Product Features

  • 1Various Types

    Standardization of number of teeth 6-720T and outer diameter φ50 to φ1500. Customized dimensions according to purpose and use.

  • 2Stiffness

    It is superior in impact resistance and high stiffness by processing high grade (Chrome Molybdenum) steel and high heat treatment.

  • 3High Restoration and Division Accuracy

    Guarantee of high restoration at the same gearing position ±5.0 seconds(precise), and division accuracy at 4 positions for ±3.0 seconds(super-precise) in case of 90º division.

  • 4Long-term Warranty

    DLC Co., Ltd. conducts strict quality inspection on all products and processes to guarantee long-term quality.

[ Drawing of Tooth ]

Drawing of Tooth

Shape of Tooth

2pccconvex teeth3pccconvex teeth
concave teethconcave teeth

Product Classification

ClassificationTypeOuter diameter, Number of teethFeatures
2PCC M Type
  • Outside diameter 30~80
  • Number of teeth 20~24
  • The type indicates the number of teeth-outer diameter-inner diameter.
It emphasizes restoration and has more than 70% restoration. It is used for turret and work exchange in the field of small precision machinery.
S Type
  • Outside diameter 100~600
  • Number of teeth 20~720
  • The type indicates the number of teeth-outer diameter-inner diameter.
It is the most common type and is used for the partitioned table of machining center that requires division accuracy, as well as NC lathes and turrets that require restoration precision. It has excellent compatibility so that it is used for pallet change.
S Type
  • Outside diameter 700~1000
  • Number of teeth 72~720
  • The type indicates the number of teeth-outer diameter-inner diameter.
It is called a large curvic. It is used to determine the division position of large machining centers or the machines. There are many sets of exchanges whereas only one side is rarely used.
W Type
  • Outside diameter 160~280
  • Number of teeth 24~60
  • The type indicates the number of teeth-outer diameter, and inner diameter-maximum outer diameter.
It is called releasing CURVIC. It can enlarge the inner diameter of tooth and the diameter of CLAMP CYLINDER. It is used for large TURRET.
3PCC T Type
  • Outside diameter 110~820
  • Number of teeth 24~270
  • The type indicates the number of teeth-outer diameter-inner diameter.
It is called 3PIECE CURVIC. It is used to rotate the WORK of heavy workpiece without floating during rotation. SET exchange is the principle, and its compatibility is less than 2PCC.

Teeth Outer Diameter Table

  • M Type
  • S Type
  • W Type
  • T Type
Teeth Outer Diameter Table

For more details,
see the catalog.

Catalog Download

Standard inspection items

ItemPrecisionSuper PrecisionDescription
Tooth contact Whole teeth contact Over 80% Over 90% Check the condition in which the tooth is closely meshed with the standard CURVIC COUPLING (GAUGE for Inspection). Since the length of the tooth is at the center of the tooth, about 50% or more of the tooth width is the default. There should not be two consecutive teeth that do not mesh with the whole teeth, and more than 80% of the teeth surface are in uniform contact.
Contact between tooth and toothOver 50%Over 50%
when in contactFlat surface vibration0.020.01It check the RUN OUT status in the DIAL GAUGE after closely meshing with the reference CURVIC COUPLING (gauge for inspection)
External diameter vibration0.020.01
Division accuracy5''3''Max cumulative error when it is divided into 4
Combined thickness±0.10±0.05The distance between the mounting surfaces when 凹 tooth and 凸 tooth are meshed

Calculation of curvic coupling strength

Calculation the stength
Strength calculation formula

Division Accuracy Table

Division Accuracy Table

As it can obtain large Camping force with sufficient stiffness, it is optimized for the partitioned table of MACHINE CENTER for medium machining and high torque transmission, but the allowable load varies depending on the size of the CURVIC COUPLING.

Since it varies depending on the allowable cutting load, allowable torque and clamping force, you need to select it according to the application in the above calculation formula.