GS 12 - AXIS GS Couplings

GS standard types - For size 5 to 38 hub material aluminium/for size 42 to 90 hub material steel
Size	Spider GS ¹⁾ torque T_KN [Nm]			D_max. for hub type			Dimensions [mm]										Setscrew DIN EN ISO 4029
Size	98 ShA	57 ShD	64 ShD	1.0	1.1	1.2	DN	DH	DI1	L	L1, L2	M, N	E	B1	S	A	G	T	TA [Nm]
12	9.0	–	12	12	12	12	–	25	8.5	34	11	–	12	10	1.0	3.5	M 4	5.0	1.5

The GS 12 Coupling (Size 12) is a compact, high-precision flexible coupling designed for demanding servo and automation applications. With an outer diameter of 25mm, it fits perfectly into the performance gap between the miniature GS 9 and the larger GS 14, offering a significant torque capacity boost (up to 9.0 Nm) for small-to-medium drive systems.

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Key Specifications (Model GS 12)

The GS 12 is a popular size for stepper and servo motors in the NEMA 23 to NEMA 34 range. Below are the standard technical specifications:

Parameter	Value
Coupling Size	GS 12 (Size 12)
Nominal Torque	5.0 Nm (92 ShA Yellow) / 9.0 Nm (98 ShA Red)
Max. Torque (Peak)	10.0 Nm to 18.0 Nm (approx. 2x Nominal)
Max. Rotational Speed	Up to 25,000 RPM
Bore Range	4 mm to 12 mm (Standard)
Outer Diameter	25 mm

How It Works

The GS 12 achieves precision through its "pre-tensioned" jaw design:

Backlash Elimination: The elastomer spider is dimensionally sized slightly wider than the gap between the coupling jaws. When the hubs are pressed together during assembly, the spider is compressed, creating a snug, interference fit that removes all backlash.
Vibration Damping: The internal spider (available in different hardness levels like 92 Shore A or 98 Shore A) acts as a mechanical filter, absorbing torque ripples and vibrations from the motor before they reach the driven load.
Misalignment Handling: While rigid in torsion for accuracy, the coupling can still flex to accommodate slight angular, parallel, and axial shaft misalignments, preventing premature bearing failure.

Benefits of GS 12 Couplings

High Torque-to-Size Ratio: Provides up to 9.0 Nm of nominal torque in a compact 25mm diameter, allowing for powerful drive connections in limited spaces.
Electrical Isolation: The polyurethane insert electrically isolates the driving and driven shafts, preventing leakage currents from damaging encoders or controllers.
Plug-In Assembly: The axial "blind mate" design allows for easy installation and removal, even when the coupling is located inside a housing or bell housing.
Low Inertia: Constructed from high-strength aluminum, the GS 12 has low mass moment of inertia, making it ideal for highly dynamic applications with fast reversing cycles.
Customizable Stiffness: By swapping the spider (e.g., from Yellow to Red), engineers can tune the stiffness and damping characteristics of the drivetrain without changing the metal hubs.

Typical Applications

The GS 12 is a standard component in precision industrial machinery:

CNC Machinery: Feed drives for 3D printers, engraving machines, and desktop mills.
Packaging Systems: Labeling machines and pick-and-place robots.
Linear Guides: Coupling servo motors to ball screws or belt drive actuators.
Semiconductor Manufacturing: Wafer handling robots and inspection stages.
Medical Devices: Automated liquid handling and scanning gantries.

Summary

The GS 12 Backlash-Free Coupling is the versatile workhorse of the miniature coupling range. capable of transmitting up to 9.0 Nm of torque, it offers the strength needed for small industrial servos while maintaining the zero-backlash precision required for high-tech automation. Its maintenance-free, vibration-damping design makes it an essential component for any high-accuracy motion control system.