Description
GT3 GT Type Sleeve Coupling – 22–32mm Bore Rigid Muff Coupling for Zero-Backlash Shaft Connection
The GT3 GT type sleeve coupling — also known as a muff coupling — is the simplest and most direct form of rigid shaft coupling: a single cylindrical steel body with a through bore machined to receive two co-linear shaft ends, transmitting torque through keyway and fitted key engagement on each shaft side. At 72 mm outer diameter and 142 mm overall length, the GT3 provides a compact, maintenance-free rigid connection for 22–32 mm shaft diameters, rated at 160 N·m nominal torque at up to 7100 rpm maximum speed. Mid-range of the light-duty GT series, the GT3 at 160 N·m and 7100 rpm covers the full torque range of fractional-to-2 kW motor shaft connections in its 22–32 mm bore class. Wood processing, pump, and textile machinery drives are primary applications.
The operating principle of the GT sleeve coupling is direct and reliable. Each shaft end is inserted into one half of the sleeve bore. A fitted key is placed in the matching keyways of both the shaft and the sleeve bore on each side — two keys total, typically positioned 180° apart. When the coupling rotates, torque is transmitted from the driving shaft to the sleeve through key-keyway bearing contact, and from the sleeve to the driven shaft through the same mechanism on the opposite side. There are no flexible elements, no preloaded fasteners to maintain, and no wear surfaces subject to degradation under normal operating conditions. The result is a permanent, zero-backlash connection that requires essentially no maintenance throughout its service life, provided the connected shafts remain accurately aligned.
The H7 bore tolerance and GB3852-1997 keyway standard ensure dimensional compatibility with standard motor and driven equipment shaft ends throughout the GT series. For special shaft configurations — non-standard diameters, tapered bores, or hydraulic fit bores — custom machining is available. The complete GT series, from GT1 through GT10, is listed on our product catalog page.
Technical Specifications
| Parameter | Value |
|---|---|
| Model | GT3 |
| Type | GT Type Sleeve Coupling (Muff Coupling) |
| Bore Range (d) | 22–32 mm |
| Outer Diameter (D) | 72 mm |
| Overall Length (L) | 142 mm |
| Nominal Torque (Tn) | 160 N·m |
| Maximum Speed [n] | 7100 rpm |
| Bore Tolerance | H7 standard |
| Keyway Standard | GB3852-1997 |
| Mass | 2.9 kg |
Dimension Reference
Construction and Functional Features
The GT3 body is machined from high-quality cast iron or cast steel — material selection dependent on model size and rated torque. The bore is machined to H7 tolerance to provide a controlled fit against the shaft end, complementing the key-keyway torque transmission with a stable radial contact between shaft and bore. The outer diameter is machined concentric with the bore to ensure rotational balance. Keyway slots are machined to GB3852-1997 standard dimensions for the specified bore size — verifying compatibility with standard motor shaft keyways without modification.
Zero Backlash
Rigid key-keyway torque transmission with no play or compliance — every angular increment on the driving shaft is replicated exactly on the driven shaft. Essential for phase-critical and encoder feedback applications.
Maintenance-Free Service Life
No wear elements, no elastomeric components to degrade, no bolts to retorque. Once correctly installed on aligned shafts, the GT sleeve coupling requires no maintenance throughout its service life.
Compact One-Piece Design
Single cylindrical body — no bolted flanges, no split halves, no external fasteners. Lowest-profile rigid coupling available for co-linear shaft connections, minimising guard size and axial space requirements.
Standard Keyway Compatibility
Bore and keyway dimensions to GB3852-1997 and H7 bore tolerance ensure direct compatibility with standard motor and driven equipment shaft ends throughout the industrial motor range.
Manufacturing Quality
Typical Applications
- Industrial fan motor to shaft connections — centrifugal and axial fan rigid drive coupling
- Paper machine roll drive connections — sustained torque rigid shaft coupling
- Mining equipment auxiliary drives — conveyor and pump rigid shaft connections in hostile environments
- Marine auxiliary machinery drives — rigid coupling for auxiliary pump and fan motor shaft connections
For technical enquiries and volume supply information, visit our contact page.
Customer Reviews and Case Studies
★★★★★
France — Wood Processing Machinery
GT3 sleeve couplings connect motor shafts to saw blade arbors on our panel processing machines. The 160 N·m torque rating handles our cutting drive loads and the rigid connection ensures accurate blade registration.
— Design Engineer, Lyon
★★★★★
India — Textile Weaving Machinery
We use GT3 on main shaft connections in our power loom product line. The 7,100 rpm speed rating covers our full motor speed range and the solid steel body has maintained its connection integrity through two years of continuous three-shift operation.
— Mechanical Engineer, Surat
★★★★☆
Brazil — Pump OEM
Installed on centrifugal pump drive shaft connections. The GT3 rigid sleeve coupling provides zero backlash, which is essential in our close-coupled pump design where angular error between motor and pump shaft would affect hydraulic balance.
— Applications Engineer, São Paulo
Frequently Asked Questions
How is the GT sleeve coupling secured on the shaft?
The sleeve is secured by the interference or transition fit between the bore and shaft, combined with the key-keyway engagement for torque transmission. For additional axial retention, a setscrew bearing on the key is often used. The sleeve should not be able to slide axially during operation — verify interference fit or add axial retention as required for your application.
What bore tolerance is standard for the GT sleeve coupling?
The standard bore tolerance is H7, suitable for shaft tolerances of k6 (transition fit) or n6 (interference fit). The fit class is selected based on the transmitted torque and whether disassembly is anticipated. For high-torque applications or where axial retention is critical, an n6 interference fit is recommended.
What is the maximum bore diameter for the GT series?
The GT series covers bore diameters from 12 mm (GT1) to 200 mm (GT10). For bores outside this range, or for intermediate sizes not listed in the standard table, contact Ever Power to discuss custom bore machining options.
Is lubrication required for the GT sleeve coupling?
No lubrication is required on the bore-shaft contact surfaces for correct installation. The bore-key contact faces may be lightly oiled during assembly to ease installation when a tight fit is used. Do not apply lubricant to the keyway flanks — this would reduce the effective friction contribution to torque transmission.
Can the GT sleeve coupling be used in high-temperature environments?
Standard cast iron and cast steel GT sleeve couplings are rated for continuous operating temperatures up to approximately 120°C. For higher-temperature applications (e.g. close-coupled drives in high-ambient environments), contact Ever Power to confirm material suitability or discuss alternative materials.
Source the GT3 GT Sleeve Coupling
Ever Power manufactures the GT3 and the complete GT sleeve coupling series — GT1 through GT10, covering 12 mm to 200 mm bore — direct from our factory. Specify bore diameters, keyway requirements, and any non-standard dimensions for a prompt technical and commercial response.