Description
GT9 GT Type Sleeve Coupling – 112–160mm Bore Rigid Muff Coupling for Zero-Backlash Shaft Connection
The GT9 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 300 mm outer diameter and 602 mm overall length, the GT9 provides a compact, maintenance-free rigid connection for 112–160 mm shaft diameters, rated at 40000 N·m nominal torque at up to 1800 rpm maximum speed. The GT9 at 40,000 N·m is specified for very large industrial drive shaft connections — primary conveyor drives, boiler feed pump motors, and large agitator gearbox inputs. Its 112–160 mm bore and 230 kg body represent the highest-capacity rigid sleeve coupling in regular industrial procurement.
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 | GT9 |
| Type | GT Type Sleeve Coupling (Muff Coupling) |
| Bore Range (d) | 112–160 mm |
| Outer Diameter (D) | 300 mm |
| Overall Length (L) | 602 mm |
| Nominal Torque (Tn) | 40000 N·m |
| Maximum Speed [n] | 1800 rpm |
| Bore Tolerance | H7 standard |
| Keyway Standard | GB3852-1997 |
| Mass | 230 kg |
Dimension Reference
Construction and Functional Features
The GT9 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
- Precision instrument and automation drives — where zero backlash and angular fidelity between shafts are required
- High-speed motor to driven shaft connections — up to the model’s maximum speed rating with minimal added inertia
- Printing and packaging machine drives — phase-critical connections where indexing accuracy is essential
- Pump direct drive connections — close-coupled motor-to-pump rigid shaft coupling
For technical enquiries and volume supply information, visit our contact page.
Customer Reviews and Case Studies
★★★★★
United Kingdom — Power Generation Equipment OEM
We specify GT9 sleeve couplings for boiler feed pump drive shaft connections at our power station equipment installations. At 40,000 N·m, the coupling covers our largest pump drive loads and the 112–160 mm bore range matches our high-power motor shaft sizes.
— Senior Mechanical Engineer, Sheffield
★★★★★
Brazil — Pulp Mill
Installed on large digester agitator drive shaft connections at our eucalyptus pulp mill. The GT9 handles the sustained high torque of our digester drive and the rigid sleeve coupling’s simple installation reduced our drive commissioning time significantly.
— Senior Mechanical Engineer, São Paulo
★★★★☆
Indonesia — Palm Oil Processing
Used on large centrifugal pump drive connections at our palm oil processing facility. The GT9’s 600 mm length provides the shaft engagement needed for reliable 40,000 N·m torque transmission at our pump shaft diameter.
— Maintenance Engineer, Medan
Frequently Asked Questions
What applications are typical for the GT9 sleeve coupling?
The GT9, with 40,000 N·m torque capacity and 112–160 mm bore, serves the largest industrial drive shaft connections — primary conveyor drives, large pump motor connections, ball mill auxiliary drives, and power station boiler feed pump drives. These applications require the highest torque-carrying capacity in the GT series.
What is the GT9’s moment of inertia and how is it used in drive system design?
The GT9 weighs 230 kg. Approximate rotational inertia: J ≈ (230 × 0.15²)/2 ≈ 2.59 kg·m². This should be reflected to the motor shaft through the gear ratio (if any) and added to the driven equipment inertia for motor sizing, soft-starter rating, and variable speed drive ramp time calculations.
How are the shaft ends supported during GT9 installation?
During GT9 sleeve installation, both shaft ends must be independently supported — either on their own bearings or on temporary support stands — to prevent sag under the shaft’s own weight. The sleeve (230 kg) must be handled with appropriate lifting equipment. The bore should be heated to 100–150°C for interference-fit installation onto large shafts.
What alignment tolerance is required before installing the GT9?
For rigid sleeve coupling installations, shaft alignment should be within 0.03–0.05 mm parallel offset and 0.05 mm/m angular deviation measured at the coupling location before the sleeve is slid into its final position. These are tighter than flexible coupling requirements — use laser alignment tools for GT9 installations.
Can GT9 sleeve couplings be custom-machined for non-standard bore diameters?
Yes. Any bore diameter within the GT9’s outer diameter constraint (300 mm OD, 112–160 mm standard bore range) can be machined on request. Non-standard bores, tapered bores, or hydraulic fit bores are available as custom options. Contact Ever Power with the required bore specification when enquiring.
Source the GT9 GT Sleeve Coupling
Ever Power manufactures the GT9 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.