MM Models

The three-layer construction of the metal coil spring component enables high torque transmission to be achieved in a compact form factor.A type that uses SUM24L-equivalent material as the hub material and piano wire for the coil spring (the MM-K type) and a type that uses stainless steel for the hub and coil spring to boost corrosion resistance (the MM-K-S type) are available. Select the type suited to your usage environment.

MM Models

[Specifications]

Model Rated Torque [N・m] Misalignment Max. rotation speed [min-1 Torsional stiffness [N・m/rad] Moment of inertia [kg・m2 Mass [kg]
Parallel [mm] Angular [°] Axial [mm]
MM-6K 2.5 0.3 3 +0.6 20000 143 7.65×10-7 0.03
MM-8K 5 0.3 3 +0.8 15000 286.5 4.08×10-6 0.07
MM-12K 10 0.4 3 +1.0 12000 573 1.43×10-5 0.14
MM-14K 10 0.5 3 +1.0 10000 573 2.47×10-5 0.15
MM-16K 20 0.6 3 +1.2 9000 1146 6.12×10-5 0.30
MM-19K 20 0.7 3 +1.2 8000 1146 8.42×10-5 0.32
MM-20K 40 0.7 3 +1.6 7000 2292 1.99×10-4 0.70
MM-24K 40 0.9 3 +1.6 7000 2292 2.63×10-4 0.75
MM-25K 90 0.9 3 +2.0 6000 3438 5.66×10-4 1.25
MM-28K 90 1.0 3 +2.0 6000 2865 5.77×10-4 1.35
MM-30K 150 1.1 3 +2.5 5000 4297.5 1.39×10-4 2.10
MM-35K 220 1.2 3 +3.2 4500 6303 3.01×10-4 3.50
Model Rated Torque [N・m] Misalignment Max. rotation speed [min-1 Torsional stiffness [N・m/rad] Moment of inertia [kg・m2 Mass [kg]
Parallel [mm] Angular [°] Axial [mm]
MM-6K-S 2.5 0.3 3 +0.6 20000 143 7.65×10-7 0.03
MM-8K-S 5 0.3 3 +0.8 15000 286.5 4.08×10-6 0.07
MM-12K-S 10 0.4 3 +1.0 12000 573 1.43×10-5 0.14
MM-16K-S 20 0.6 3 +1.2 9000 1146 6.12×10-5 0.30
MM-20K-S 40 0.7 3 +1.6 7000 2292 1.99×10-4 0.70
MM-25K-S 90 0.9 3 +2.0 6000 3438 5.66×10-4 1.25
*Max. rotation speed does not take into account dynamic balance. *The moment of inertia and mass are measured for the maximum bore diameter.

[Dimensions]

Unit [mm]
Model d1, d2 D L L1 E F
Pilot bore Min. Max.
MM-6K 2.5 3 8 16 20 6 11 15.5
MM-8K 3.5 4 8 21 35 11 13 19
MM-12K 5.5 6 12 26 50 16.5 16.5 24
MM-14K 5.5 7 14 30 50 16.5 20.5 28
MM-16K 5.5 10 16 35 65 22 22.4 32
MM-19K 5.5 10 19 38 65 22 26.4 36
MM-20K 5.5 10 20 45 80 27 28 40
MM-24K 5.5 14 24 48 80 27 33 45
MM-25K 5.5 14 25 55 100 33.5 35 50
MM-28K 5.5 14 28 55 100 33.5 37 52
MM-30K 5.5 16 30 65 125 40 40.8 60
MM-35K 5.5 20 35 75 150 48 46 70
Unit [mm]
Model d1, d2 D L L1 E F
Pilot bore Min. Max.
MM-6K-S 2.5 3 8 17 25 9 11 15.5
MM-8K-S 3.5 4 8 21 35 11 13 19
MM-12K-S 5.5 6 12 26 50 16.5 16.5 24
MM-16K-S 5.5 10 16 35 65 22 22.4 32
MM-20K-S 5.5 10 20 45 80 27 28 40
MM-25K-S 5.5 14 25 55 100 32.5 35 50
*Pilot bores are to be drilled into the part.

[Standard Hole-drilling Standards]

Unit [mm]
Models compliant with the old JIS standard (class 2) JIS B 1301 1959 Models compliant with the new JIS standard (H9) JIS B 1301 1996 Models compliant with the new JIS standard (JS9) JIS B 1301 1996 Models compliant with the motor standard JIS C 4210 2001
Nominal bore diameter Bore diameter [d1・d2] Keyway width [W1・W2] Keyway height [T1・T2] Set screw hole [M] Nominal bore diameter Bore diameter [d1・d2] Keyway width [W1・W2] Keyway height [T1・T2] Set screw hole [M] Nominal bore diameter Bore diameter [d1・d2] Keyway width [W1・W2] Keyway height [T1・T2] Set screw hole [M] Nominal bore diameter Bore diameter [d1・d2] Keyway width [W1・W2] Keyway height [T1・T2] Set screw hole [M]
Tolerance H7,H8 Tolerance E9 Tolerance H7 Tolerance H9 Tolerance H7 Tolerance JS9 Tolerance G7,F7 Tolerance H9
4 4+0.0180 2-M3
5 5+0.0180 2-M3
6 6+0.0180 2-M4
6.35 6.35+0.0220 2-M4
7 7+0.0220 2-M4
8 8+0.0220 2-M4
9 9+0.0220 2-M4
9.5 9.5+0.0220 2-M4
9.525 9.525+0.0220 2-M4
10 10+0.0220 2-M4
11 11+0.0180 2-M4
12 12+0.0180 4+0.050+0.020 13.5+0.30 2-M4 12H 12+0.0180 4+0.0300 13.8+0.30 2-M4 12J 12+0.0180 4±0.0150 13.8+0.30 2-M4
14 14+0.0180 5+0.050+0.020 16.0+0.30 2-M4 14H 14+0.0180 5+0.0300 16.3+0.30 2-M4 14J 14+0.0180 5±0.0150 16.3+0.30 2-M4 14N 14+0.024+0.006 5+0.0300 16.3+0.30 2-M4
15 15+0.0180 5+0.050+0.020 17.0+0.30 2-M4 15H 15+0.0180 5+0.0300 17.3+0.30 2-M4 15J 15+0.0180 5±0.0150 17.3+0.30 2-M4
16 16+0.0180 5+0.050+0.020 18.0+0.30 2-M4 16H 16+0.0180 5+0.0300 18.3+0.30 2-M4 16J 16+0.0180 5±0.0150 18.3+0.30 2-M4
17 17+0.0180 5+0.050+0.020 19.0+0.30 2-M4 17H 17+0.0180 5+0.0300 19.3+0.30 2-M4 17J 17+0.0180 5±0.0150 19.3+0.30 2-M4
18 18+0.0180 5+0.050+0.020 20.0+0.30 2-M4 18H 18+0.0180 6+0.0300 20.8+0.30 2-M5 18J 18+0.0180 6±0.0150 20.8+0.30 2-M5
19 19+0.0210 5+0.050+0.020 21.0+0.30 2-M4 19H 19+0.0210 6+0.0300 21.8+0.30 2-M5 19J 19+0.0210 6±0.0150 21.8+0.30 2-M5 19N 19+0.028+0.007 6+0.0300 21.8+0.30 2-M5
20 20+0.0210 5+0.050+0.020 22.0+0.30 2-M4 20H 20+0.0210 6+0.0300 22.8+0.30 2-M5 20J 20+0.0210 6±0.0150 22.8+0.30 2-M5
22 22+0.0210 7+0.061+0.025 25.0+0.30 2-M6 22H 22+0.0210 6+0.0300 24.8+0.30 2-M5 22J 22+0.0210 6±0.0150 24.8+0.30 2-M5
24 24+0.0210 7+0.061+0.025 27.0+0.30 2-M6 24H 24+0.0210 8+0.0360 27.3+0.30 2-M6 24J 24+0.0210 8±0.0180 27.3+0.30 2-M6 24N 24+0.028+0.007 8+0.0360 27.3+0.30 2-M6
25 25+0.0210 7+0.061+0.025 28.0+0.30 2-M6 25H 25+0.0210 8+0.0360 28.3+0.30 2-M6 25J 25+0.0210 8±0.0180 28.3+0.30 2-M6
28 28+0.0210 7+0.061+0.025 31.0+0.30 2-M6 28H 28+0.0210 8+0.0360 31.3+0.30 2-M6 28J 28+0.0210 8±0.0180 31.3+0.30 2-M6 28N 28+0.028+0.007 8+0.0360 31.3+0.30 2-M6
30 30+0.0210 7+0.061+0.025 33.0+0.30 2-M6 30H 30+0.0210 8+0.0360 33.3+0.30 2-M6 30J 30+0.0210 8±0.0180 33.3+0.30 2-M6
32 32+0.0250 10+0.061+0.025 35.5+0.30 2-M8 32H 32+0.0250 10+0.0360 35.3+0.30 2-M8 32J 32+0.0250 10±0.0180 35.3+0.30 2-M8
35 35+0.0250 10+0.061+0.025 38.5+0.30 2-M8 35H 35+0.0250 10+0.0360 38.3+0.30 2-M8 35J 35+0.0250 10±0.0180 38.3+0.30 2-M8
* These standard bore drilling standards apply to BAUMANNFLEX MM/MF models. * All standards starting from ø11 are the same as those in the old JIS standards column. * Positions of set screws and keyways are not on the same plane. * Set screws are included with the product. * Positioning precision for keyway milling is determined by sight. * Contact Miki Pulley when the keyway requires a positioning precision for a particular flange hub. * Consult the technical documentation at the end of this volume for standard dimensions for bore drilling other than those given here.

[Set screw position]

Coupling size Distance C from edge [mm]
6 3
8 5
12・14 7
16・19・20・24 10
25・28・30・35 15