MM Model

This metal coupling utilizes the elasticity of a spring structure and incorporates a metal coil spring. This model offers high flexibility and is capable of accommodating significant misalignments, such as eccentricity and angular misalignment.The MM model is a flexible coupling that achieves compact dimensions and high torque transmission through a three-layer coil spring structure.

[Specifications]

Model Rated Torque Tolerance Maximum Rotational Speed Torsional spring constant Moment of inertia Mass Price of pre-drilled products
[N·m] Eccentricity [mm] Angular offset [°] Axial [mm] [min⁻¹] [N·m/rad] [kg·m²] [kg] [yen]
MM-6K 2.5 0.3 3 0.6 20,000 143 7.65×10⁻⁷ 0.03
MM-8K 5 0.3 3 0.8 15,000 286.5 4.08×10⁻⁶ 0.07
MM-12K 10 0.4 3 1 12,000 573 1.43×10⁻⁵ 0.14
MM-14K 10 0.5 3 1 10,000 573 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 6000 3438 5.66×10⁻⁴ 1.25
MM-28K 90 1 3 2 6000 2865 5.77×10⁻⁴ 1.35
MM-30K 150 1.1 3 2.5 5000 4297.5 1.39×10⁻³ 2.10
MM-35K 220 1.2 3 3.2 4500 6303 3.01×10⁻³ 3.50
  • The maximum rotational speed does not take dynamic balance into account.
  • The moment of inertia and mass are based on the maximum bore diameter.

[Dimensions]

三木プーリのバウマンフレックス MMタイプ コイルばね・スリットカップリング寸法図(高剛性・軸ずれ吸収・精密軸継手)
Model d1・d2 [mm] D [mm] L [mm] L1 [mm] E [mm] F [mm]
Pilot hole Minimum 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

  • The pilot hole will be a drill hole.

[Standard Hole Machining Specifications]

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JIS Keyway Specifications Table
Unit [mm]
Corresponds to JIS Old Standard Type 2 JIS B 1301 1959 New JIS Standard H9 (Compliant with JIS B 1301:1996) New JIS Standard (Heisei 9) JIS B 1301 1996 Motor Standard: Compliant with JIS C 4210 2001
Nominal hole diameter Bore Diameter
(d1, d2)
Keyway width
(W1, W2)
Keyway depth
(T1, T2)
Set screw hole
(M)
Nominal hole diameter Hole diameter
(d1, d2)
Keyway width
(W1, W2)
Keyway depth
(T1, T2)
Set screw hole
(M)
Nominal hole diameter Hole diameter
(d1, d2)
Keyway width
(W1, W2)
Keyway depth
(T1, T2)
Set screw hole
(M)
Nominal hole diameter Hole diameter
(d1, d2)
Keyway width
(W1, W2)
Keyway depth
(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
7 7 + 0.0220 2-M4
8 8 + 0.0220 2-M4
9 9 + 0.0220 2-M4
10 10 + 0.0220 2-M4
11 11 + 0.0180 2-M4
12 12 + 0.0180 4 + 0.05 + 0.02 13.5 + 0.30 2-M4 12H 12 + 0.0180 4 + 0.030 13.8 + 0.30 2-M4 12J 12 + 0.0180 4 + 0.015 – 0.015 13.8 + 0.30 2-M4
14 14 + 0.0180 5 + 0.05 + 0.02 16.0 + 0.30 2-M4 14H 14 + 0.0180 5 + 0.030 16.3 + 0.30 2-M4 14J 14 + 0.0180 5 + 0.015 – 0.015 16.3 + 0.30 2-M4 14N 14 + 0.024 + 0.006 5 + 0.030 16.3 + 0.30 2-M4
15 15 + 0.0180 5 + 0.05 + 0.02 17.0 + 0.30 2-M4 15H 15 + 0.0180 5 + 0.030 17.3 + 0.30 2-M4 15J 15 + 0.0180 5 + 0.015 – 0.015 17.3 + 0.30 2-M4
16 16 + 0.0180 5 + 0.05 + 0.02 18.0 + 0.30 2-M4 16H 16 + 0.0180 5 + 0.030 18.3 + 0.30 2-M4 16J 16 + 0.0180 5 + 0.015 – 0.015 18.3 + 0.30 2-M4
17 17 + 0.0180 5 + 0.05 + 0.02 19.0 + 0.30 2-M4 17H 17 + 0.0180 5 + 0.030 19.3 + 0.30 2-M4 17J 17 + 0.0180 5 + 0.015 – 0.015 19.3 + 0.30 2-M4
18 18 + 0.0180 5 + 0.05 + 0.02 20.0 + 0.30 2-M4 18H 18 + 0.0180 6 + 0.030 20.8 + 0.30 2-M5 18J 18 + 0.0180 6 + 0.015 – 0.015 20.8 + 0.30 2-M5
19 19 + 0.0210 5 + 0.05 + 0.02 21.0 + 0.30 2-M4 19H 19 + 0.0210 6 + 0.030 21.8 + 0.30 2-M5 19J 19 + 0.0210 6 + 0.015 – 0.015 21.8 + 0.30 2-M5 19N 19 + 0.028 + 0.007 6 + 0.030 21.8 + 0.30 2-M5
20 20 + 0.0210 5 + 0.05 + 0.02 22.0 + 0.30 2-M4 20H 20 + 0.0210 6 + 0.030 22.8 + 0.30 2-M5 20J 20 + 0.0210 6 + 0.015 – 0.015 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 + 0.030 24.8 + 0.30 2-M5 22J 22 + 0.0210 6 + 0.015 – 0.015 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 + 0.018 – 0.018 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 + 0.018 – 0.018 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 + 0.018 – 0.018 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 + 0.018 – 0.018 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 + 0.018 – 0.018 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 + 0.018 – 0.018 38.3 + 0.30 2-M8

  • This standard hole drilling specification applies to Baumannflex MM and MF models.
  • All specifications for diameters of 11 mm or less are identical to those listed in the "Old JIS Standards" column.
  • The set screws are not located on the same plane.
  • The set screw is included with the product.
  • The positional accuracy of keyway machining is checked visually.
  • Please contact us if you require positional accuracy for the keyways relative to each hub.
  • For standard dimensions of hole patterns other than those listed here, please refer to the technical data at the end of this document.
三木プーリのバウマンフレックス MMモデル コイルばね・スリットカップリング ご注文時の型式構成説明図

[Location of the set screw]

Position Table from End Face
Coupling Size Distance C from end face [mm]
6 3
8 5
12・14 7
16, 19, 20, 24 10
25, 28, 30, 35 15