GS 7 - 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]
7	2.0	–	2.4	7	7	7	–	14	–	22	7	–	8	6	1.0	6.0	M 3	3.5	0.6

The GS 7 Coupling (Size 07) is a miniature, high-precision servo coupling designed for applications requiring exact positioning and zero backlash. Slightly larger than the GS 5, the GS 7 offers increased torque capacity while maintaining a compact footprint, making it the preferred choice for connecting feedback devices and small servo motors in automation systems.

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Key Specifications (Model GS 7)

The GS 7 strikes a balance between compact size and usable torque for small automation. Below are the standard technical specifications:

Parameter	Value
Coupling Size	GS 7 (Size 07)
Nominal Torque	2.0 Nm (92 ShA Spider) / 2.4 Nm (98 ShA Spider)
Max. Rotational Speed	Up to 40,000 RPM
Bore Range	3mm to 7mm
Outer Diameter	14 mm
Hub Material	High-Strength Aluminum

How It Works

The GS 7 operates on a pre-tensioned, backlash-free principle:

Interlocking Design: The aluminum hubs feature concave "jaws" that interlock with a star-shaped elastomer insert (spider).
Pre-Stress Assembly: The spider is dimensionally slightly larger than the gap between the jaws. When assembled, it is compressed, creating a tight, zero-backlash fit that eliminates any "play" between the input and output shafts.
Load Distribution: The curved jaw profile ensures that contact pressure is distributed over a larger area of the spider tooth, allowing the GS 7 to handle higher torque density than straight-jaw equivalents.

Benefits of GS 7 Couplings

Zero Backlash: Essential for precision tasks, ensuring that every degree of motor rotation is instantly transferred to the load without lag or hysteresis.
Vibration Damping: The polyurethane spider absorbs torsional vibration and shock loads, resulting in smoother operation and reduced noise in sensitive machinery.
Electrical Isolation: Prevents ground loops and electrical noise from interfering with encoders or controllers by isolating the motor shaft from the driven equipment.
Plug-In Assembly: The design allows for blind assembly (axial plug-in), making it easy to install in tight spaces where tools cannot reach.
Low Inertia: The small 14mm diameter and aluminum construction minimize rotational mass, allowing for high dynamic performance and rapid reversing.

Typical Applications

The GS 7 is widely used in precision industries:

Feedback Devices: Connecting rotary encoders, resolvers, and tachometers.
Medical Technology: Dosing pumps and analytical instruments.
Semiconductor Handling: Pick-and-place machines and wafer handling robots.
Small CNC Machines: Axis drives for miniature milling or engraving machines.
Textile Machinery: Sensor connections and thread tensioning drives.

Summary

The GS 7 Backlash-Free Coupling is a critical component for high-precision motion control. With a nominal torque rating of ~2.0 Nm and an outer diameter of just 14mm, it fits perfectly into the gap between micro-drives and larger servo systems. Whether you are building a medical device or a robotic joint, the GS 7 offers the accuracy and reliability required for modern automation.