• Couplings
  • Disk Type


Flexible Couplings - Disk Type - Clamping Type

  • Zero Backlash
  • High torsional rigidity
  • High Torque

Dimension Drawing

XBWS-CFlexible Couplings - Disk Type - Clamping Type寸法図


Part Number ALWEFGM Screw Tightening
Torque (N・m)
Standard Bore Diameter
Add to Cart Additional Modification
XBWS-56C3A 56 20 60.4 29 6 21.25 M5 8 - 362.27 CAD Cart       

All products are provided with hex socket head cap screw.
Recommended tolerance for shaft diameters is h6 and h7.
In case of mounting on D-cut shaft, be careful about the position of the D-cut surface of the shaft. ⇒Mounting and Maintenance

Part Number Max. Bore Diameter
Max. Rotational Frequency
Moment of
Max. Lateral Misalignment
Max. Angular
Max. Axial
(g) *2
XBWS-56C3A 28 14 11000 2.9×10-4 10000 0.3 2 ±0.8 800

*1: Correction of rated torque due to load fluctuation is not required. For more detailed information, please refer to Selection Guidelines.

※ The shaft's slip torque may be smaller than the coupling's rated torque depending on the shaft bore. XBW-C

*2: These are values with max. bore diameter.

Part Number Standard Bore Diameter D1・D2
3 4 5 6 8 10 11 12 14 15 16 18 19 20 22 24 25 28
XBWS-56C3A - - - - -

● All products are provided with hex socket head cap screw.
● Recommended tolerance for shaft diameters is h6 and h7.
● Bore and keyway modifications are available on request. Please take advantage of our modification services.

Slip torque

As in the table below, the clamping types XBW-C and XBWS-C have different slip torque according to the bore diameter. Take care during selection.

Unit : N・m

Part Number Bore Diameter (mm)
3 4 6 8 10 11 14 15
XBW-15C2 1
XBW-19C2 1.6
XBW-34C3 5.2 6
XBW-44C2 15
XBW-56C3 25 32
XBW-68C5 80 100

These are test values based on the conditions of shaft dimensional allowance: h7, hardness: 34-40 HRC, and screw tightening torque of the values described in XBW-CXBWS-C dimension tables. They are not guaranteed values.
Slip torque changes with usage conditions. Carry out tests under conditions similar to actual conditions in advance.

Unit : N・m

Part Number Bore Diameter (mm)
4 6 8 10 11 12 14 15
XBWS-19C2A 1
XBWS-34C3A 5
XBWS-39C2A 5.5 8
XBWS-44C2A 4.5 6 10
XBWS-56C3A 9 13 18 25 28


Clamping TypeXBW-CXBWS-C

XBW-CAluminum Alloy Hub
XBWS-C Made of All Stainless Steel

XBW-C/XBWS-C_CFlexible Couplings - Disk Type


Hub SUS303
Spacer SUS303
Disk SUS304
Collar SUS304
Hex Socket Head Cap Screw SUSXM7


  • Recommended Applicable Motor
Stepping Motor
General-purpose Motor

◎: Excellent ○: Very good ●: Available

  • Property
Zero Backlash
High Torque
High Torsional Stiffness
Allowable Misalignment
Corrosion Resistance (All S.S.) -

◎: Excellent ○: Very good

  • This is a disk type flexible coupling.
  • The stainless steel disk allows eccentricity, and angular misalignment, and end-play.
  • Wide variation of outside diameter φ 15 - φ 104 and bore diameter φ 3 - φ 50.
  • Extra super duralumin (A7075) featuring the highest strength among aluminum alloy is adopted for XBW-C hubs.
  • XBWS-C is the all stainless steel type with stainless steel hubs.


Actuator / Surface-mount machine / High precision XY stage / Index table


Selection Based on Shaft Diameter and Rated Torque

The area bounded by the shaft diameter and rated torque indicates the selection size.

XBW-C/XBWS-C_CFlexible Couplings - Disk Type

XBW-C/XBWS-C_CFlexible Couplings - Disk Type

XBW-C/XBWS-C_CFlexible Couplings - Disk Type

Selection Example

In case of selected parameters of shaft diameter of φ30 and load torque of 40 N•m, the selected size is XBW-68C5.

Selection Based on the Rated Output of the Servomotor

Rated Output
Servomotor Specifications*1 Selection Size
Diameter of Motor Shaft
Rated Torque
Instantaneous Max. Torque
Aluminum Alloy Hub Made of All Stainless Steel
10 5 - 6 0.032 0.096 XBW-15C XBWS-15C
20 5 - 6 0.064 0.19 XBW-15C XBWS-15C
30 5 - 7 0.096 0.29 XBW-19C XBWS-19C
50 6 - 8 0.16 0.48 XBW-19C XBWS-19C
100 8 0.32 0.95 XBW-19C XBWS-25C
200 9 - 14 0.64 1.9 XBW-27C XBWS-34C
400 14 1.3 3.8 XBW-34C XBWS-39C
750 16 - 19 2.4 7.2 XBW-39C XBWS-56C

*1: Motor specifications are based on general values. For details, see the motor manufacturer's catalogs. This is the size for cases where devices such as reduction gears are not used.

Eccentric Reaction Force

XBW-C/XBWS-C_TTechnical Information

XBW-C/XBWS-C_TTechnical Information

Thrust reaction force

XBW-C/XBWS-C_TTechnical Information

XBW-C/XBWS-C_TTechnical Information

Change in static torsional stiffness due to temperature

This is a value under the condition where the static torsional stiffness at 20°C is 100%.
The change of XBW-C and XBWS-C in torsional stiffness due to temperature is small and the change in responsiveness is extremely small. If the unit is used under higher temperature, be careful about misalignment due to elongation or deflection of the shaft associated with thermal expansion.

XBW-C/XBWS-C_TTechnical Information

Static torsional stiffness comparison (disc-type)

XBW-C/XBWS-C_TTechnical Information

Related Products

The Double-Disk type Flexible Coupling XHW-C is compatible with the servomotor with 350% instantaneous max. torque is available.

XBW-C/XBWS-C_CFlexible Couplings - Disk Type

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