Description
GY9/GYS9/GYH9 Flanged Coupling – 71–100mm Bore Rigid Flange Coupling to GB/T 5843-2003
The GY9/GYS9/GYH9 type flanged coupling is the most widely used rigid coupling for cylindrical shaft connections in industrial machinery — conforming to Chinese national standard GB/T 5843-2003. Three structural subtypes are available within each model number: GY type, which uses a hinge bolt hole system allowing assembly and disassembly without moving the coupling along the axial direction; GYS type, which adds a precision alignment boss (凸楔) at the flange mating face to ensure accurate shaft concentricity on reassembly without realignment measurement; and GYH type, which uses a ring (sleeve) design that assembles and disassembles by axial movement. All three subtypes share the same outer diameter (260 mm), bore range (71–100 mm), nominal torque (6300 N·m), and maximum speed (3600 rpm). GY9/GYS9/GYH9 at 6,300 N·m and 71–100 mm bore serves the 250 kW–1 MW industrial drive class. At 3600 rpm, the three subtypes cover large pump, compressor, and fan drive motor connections. This bore and torque class is at the core of heavy industrial drive coupling specifications.
The coupling transmits torque through a bolted flange joint — each hub mounts on one shaft via keyway and key, and the two hub flanges are bolted together with reamed-hole precision bolts. This provides a rigid, zero-backlash connection with no flexible elements. The GY-type hinge bolt design allows the coupling to be disconnected by removing the flange bolts without requiring either shaft to move axially — a significant maintenance advantage over sleeve couplings. The GYS-type alignment boss further improves maintenance efficiency by ensuring the two hub halves re-centre precisely on reconnection, eliminating the need for dial indicator verification after each coupling reconnection in planned maintenance schedules.
Shaft hole dimensions and keyway forms comply with GB3852-1997. Both Y-type and J-type bores are available; tapered bores are also available. The complete GY/GYS/GYH coupling series is listed on our product catalog page.
Technical Specifications
| Parameter | Value |
|---|---|
| Model Numbers | GY9, GYS9, GYH9 |
| Standard | GB/T 5843-2003 |
| Bore Range (d1, d2) | 71–100 mm |
| Outer Diameter (D) | 260 mm |
| Flange Boss Width (b) | 66 mm |
| Ring Width (b1, GYH) | 84 mm |
| Face Gap (S) | 10 mm |
| Nominal Torque (Tn) | 6300 N·m |
| Maximum Speed [n] | 3600 rpm |
| Rotational Inertia | 0.319 kg·m² |
| Mass (approx.) | 47.8 kg |
| Material | Cast Iron (HT200) standard; cast steel available |
| Bore Type | Y-type, J-type, or tapered bore |
GY, GYS and GYH Subtype Dimension Reference
Three Subtype Comparison
GY Type – Hinge Bolt
The standard GY type uses a hinge bolt hole system. Assembly and disassembly are performed by removing the flange bolts — no axial shaft movement required. This is the simplest GY subtype and is specified when maintenance reconnection frequency is low or when realignment is acceptable.
GYS Type – Alignment Boss
GYS type adds a precision alignment boss (凸楔) at the flange mating face. When reassembled after maintenance, the boss centres the two hub halves concentrically, eliminating realignment measurement. Specified where frequent planned maintenance disconnection is required and realignment time must be minimised.
GYH Type – Ring Design
GYH type uses a ring (sleeve) structural element and assembles by axial movement along the shaft. This method suits installations where the coupling geometry requires axial assembly access. Processing convenience is noted as a feature; disassembly also moves along the axial direction.
Zero Backlash – All Subtypes
All three GY subtypes transmit torque through rigid bolted flange joints and key-keyway shaft connections — providing absolute zero backlash. The rated 6300 N·m and 3600 rpm apply equally to GY, GYS, and GYH configurations.
Manufacturing Quality
Typical Applications
- Motor test bench and dynamometer drive connections — GY/GYS/GYH type with three assembly method options for different test configurations
- High-speed motor shaft connections — rigid flanged coupling at the model’s maximum speed rating
- Precision instrument and automation drive connections — zero-backlash flanged coupling for phase and position accuracy
- Printing machine and textile roll drive connections — rigid shaft coupling for precise phase registration
For volume supply and custom bore configurations, visit our contact page.
Customer Reviews and Case Studies
★★★★★
Germany — Large Industrial Pump and Compressor OEM
GY9, GYS9, and GYH9 type flanged couplings are standard on our largest pump and compressor product lines. At 6,300 N·m and 3,600 rpm, the coupling covers our 500 kW–1 MW drive connections and GYS9 is standard for all API pump specifications.
— Chief Design Engineer, Mannheim
★★★★★
Australia — Mining Processing Plant
GY9 type couplings are installed on large thickener rake drive motor connections at our gold processing facility. The coupling handles the variable torque loading of the rake drive reliably in continuous operation.
— Rotating Equipment Manager, Kalgoorlie
★★★★☆
Brazil — Pulp Mill
GY9 and GYS9 type couplings are used on large digester and stock preparation pump drives. The GYS9 alignment boss simplifies our planned maintenance pump reconnection procedure significantly.
— Maintenance Manager, Três Lagoas
Frequently Asked Questions
What are the three subtypes of GY series flanged coupling and how do they differ?
GY type uses a hinge bolt hole system for assembly and disassembly without moving along the axial direction. GYS type adds a centre alignment boss (tenon) on the flange face that ensures accurate shaft concentricity when the coupling is reconnected after maintenance. GYH type uses a ring (coupling sleeve) design and disassembles by moving along the axial direction. All three subtypes share the same outer diameter D, bore range, and torque/speed ratings.
What standard do GY/GYS/GYH flanged couplings conform to?
GY, GYS, and GYH type flanged couplings conform to Chinese national standard GB/T 5843-2003, which governs flange coupling design, dimensions, and performance. Keyway and shaft hole dimensions comply with GB3852-1997. The standard is noted as the most widely used rigid coupling standard for cylindrical shaft connections in industrial machinery.
What is the difference between GY and YL type flanged couplings?
Both are rigid bolted flanged couplings for cylindrical shaft connections. GY/GYS/GYH conform to GB/T 5843-2003 and are designed as the most widely used general-purpose rigid coupling. YL/YLD conform to GB 5843-86, an earlier standard. The GY series offers three structural subtypes (GY, GYS, GYH) providing assembly flexibility; the YL series offers a standard type (YL) and spacer type (YLD). Both provide zero-backlash rigid torque transmission.
Can GY, GYS, and GYH hubs be interchanged?
GY, GYS, and GYH subtypes within the same model number (e.g. GY5, GYS5, GYH5) share the same bolt circle diameter and bolt specification. In principle, GY and GYS hubs can be used together at the same mating flange. GYH type uses a different assembly method and may require both halves to be GYH type. Confirm interchangeability with Ever Power for your specific application.
What bore types are available for GY/GYS/GYH couplings?
Both Y-type (standard cylindrical bore with keyway) and J-type (short hub cylindrical bore with keyway) are available. A tapered bore (cone bore) is also available — noted in the standard as ‘shaft hole pattern can also be a cone.’ Specify the bore type and keyway dimensions when placing your order.
Source GY9/GYS9/GYH9 Flanged Couplings
Ever Power manufactures GY, GYS, and GYH type flanged couplings from GY1 to GY12 per GB/T 5843-2003, direct from our factory. Specify subtype (GY/GYS/GYH), bore sizes, bore type (Y/J/tapered), and material for a prompt technical and commercial response.