• Couplings
  • Bellows Type


Flexible Couplings - Bellows Type

  • Zero Backlash
  • Constant Velocity
  • Simple

Dimension Drawing

MFBSFlexible Couplings - Bellows Type寸法図

*1: In a case where the bore diameter is φ 4 or less, the set screw is used in only one place.


Part Number ALWEFM Screw Tightening
Torque (N・m)
Standard Bore Diameter (Dimensional Allowance H8)
CAD Add to Cart Additional Modification
MFBS-16 16 9 26.5 9.5 3 M3 0.7 - 66.36 CAD Cart       

Part Number Max. Bore Diameter
Max. Rotational Frequency
Moment of
Max. Lateral Misalignment
Max. Angular Misalignment (°) Max. Axial
(g) *2
MFBS-16 8 1 39000 8.0×10-7 150 0.1 1.5 -1.2~+0.4 20

*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. MFBMFBSMFB-C

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

Part Number Standard Bore Diameter (Dimensional Allowance H8)
3 4 5 6 8 10 12 14
MFBS-16 - - - -

● All products are provided with hex socket set screws.
● Tolerance of shaft bore on set screw type is H8.
● 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 type MFBS-C has different slip torque according to the bore diameter. Take care during selection.

Unit : N・m

Part Number Bore Diameter (mm)
4 5 6 8 10 12
MFBS-12C 0.4 0.6
MFBS-16C 0.9 1.9
MFBS-20C 1.6 1.8
MFBS-25C 2.2 2.9
MFBS-32C 3 3.4 4.1

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 MFBS-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.


Set Screw Type


MFB/MFBS/MFB-C/MFBS-C_CFlexible Couplings - Bellows Type

MFBSMade of all stainless steelMFBMFBSMFB-CMFBS-C

MFB/MFBS/MFB-C/MFBS-C_CFlexible Couplings - Bellows Type

Clamping Type


MFB/MFBS/MFB-C/MFBS-C_CFlexible Couplings - Bellows Type

MFBS-CMade of all stainless steelMFBMFBSMFB-CMFBS-C

MFB/MFBS/MFB-C/MFBS-C_CFlexible Couplings - Bellows Type


Hub SUS303
Bellows SUS316L
Hex Socket Set Screw SUSXM7
Hex Socket Head Cap Screw SUSXM7


  • Recommended Applicable Motor
Stepping Motor
General-purpose Motor

◎: Excellent ○: Very good ●: Available

  • Property
Zero Backlash
Allowable Misalignment
Corrosion Resistance (All S.S.) -

◎: Excellent ○: Very good

  • This is a bellows type flexible coupling.
  • The bellows allows eccentricity, angular misalignment, and end-play.
  • Even if there is misalignment, the constant revolution is performed.
  • There are two types of bellows: phosphor bronze type and stainless steel type.



Precautions for Use

In case of mounting on D-cut shaft, be careful about the position of the D-cut surface of the shaft. ⇒Mounting and Maintenance
There are sizes where the hex socket head bolt exceeds the outer diameter of the coupling and the rotating diameter is larger than the outer diameter. Please be careful of the interference of coupling. 


Selection Based on Shaft Diameter and Rated Torque

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

MFB/MFBS/MFB-C/MFBS-C_CFlexible Couplings - Bellows Type

MFB/MFBS/MFB-C/MFBS-C_CFlexible Couplings - Bellows Type

Selection Example

In case of selected parameters of shaft diameter of φ10 and load torque of 2 N・m, the selected size forMFBMFB-32.

Eccentric Reaction Force

MFB/MFBS/MFB-C/MFBS-C_TTechnical Information

MFB/MFBS/MFB-C/MFBS-C_TTechnical Information

Thrust reaction force

MFB/MFBS/MFB-C/MFBS-C_TTechnical Information

MFB/MFBS/MFB-C/MFBS-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 MFB and MFBS 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.

MFB/MFBS/MFB-C/MFBS-C_TTechnical Information

MFB/MFBS/MFB-C/MFBS-C_TTechnical Information

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