{"id":3598,"date":"2026-07-08T08:34:21","date_gmt":"2026-07-08T08:34:21","guid":{"rendered":"https:\/\/rigid-shaft-coupling.top\/product\/gy8-gys8-gyh8-flanged-coupling-56-80mm-bore-rigid-flange-coupling-gb-t5843-2003\/"},"modified":"2026-07-08T08:34:23","modified_gmt":"2026-07-08T08:34:23","slug":"gy8-gys8-gyh8-flanged-coupling-56-80mm-bore-rigid-flange-coupling-gb-t5843-2003","status":"publish","type":"product","link":"https:\/\/rigid-shaft-coupling.top\/ar\/product\/gy8-gys8-gyh8-flanged-coupling-56-80mm-bore-rigid-flange-coupling-gb-t5843-2003\/","title":{"rendered":"GY8\/GYS8\/GYH8 Flanged Coupling \u2013 56\u201380mm Bore Rigid Flange Coupling GB\/T5843-2003"},"content":{"rendered":"
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GY8\/GYS8\/GYH8 Flanged Coupling \u2013 56\u201380mm Bore Rigid Flange Coupling to GB\/T 5843-2003<\/h1>\n

The GY8\/GYS8\/GYH8 type flanged coupling<\/strong> is the most widely used rigid coupling for cylindrical shaft connections in industrial machinery \u2014 conforming to Chinese national standard GB\/T 5843-2003. Three structural subtypes are available within each model number: GY type<\/strong>, which uses a hinge bolt hole system allowing assembly and disassembly without moving the coupling along the axial direction; GYS type<\/strong>, which adds a precision alignment boss (\u51f8\u6954) at the flange mating face to ensure accurate shaft concentricity on reassembly without realignment measurement; and GYH type<\/strong>, which uses a ring (sleeve) design that assembles and disassembles by axial movement. All three subtypes share the same outer diameter (200 mm), bore range (56\u201380 mm), nominal torque (3150 N\u00b7m), and maximum speed (4800 rpm). At 3,150 N\u00b7m and 56\u201380 mm bore, GY8\/GYS8\/GYH8 serves the largest directly coupled industrial drives in the 90\u2013250 kW motor class. The coupling group at 4800 rpm covers all direct motor connection configurations. GYS8 with alignment boss is standard for API process pump applications at this bore and torque level.<\/p>\n

The coupling transmits torque through a bolted flange joint \u2014 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 \u2014 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.<\/p>\n

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<\/a>.<\/p>\n

Technical Specifications<\/h2>\n
\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Parameter<\/th>\nValue<\/th>\n<\/tr>\n<\/thead>\n
Model Numbers<\/td>\nGY8, GYS8, GYH8<\/td>\n<\/tr>\n
Standard<\/td>\nGB\/T 5843-2003<\/td>\n<\/tr>\n
Bore Range (d1, d2)<\/td>\n56\u201380 mm<\/td>\n<\/tr>\n
Outer Diameter (D)<\/td>\n200 mm<\/td>\n<\/tr>\n
Flange Boss Width (b)<\/td>\n50 mm<\/td>\n<\/tr>\n
Ring Width (b1, GYH)<\/td>\n68 mm<\/td>\n<\/tr>\n
Face Gap (S)<\/td>\n10 mm<\/td>\n<\/tr>\n
Nominal Torque (Tn)<\/td>\n3150 N\u00b7m<\/td>\n<\/tr>\n
Maximum Speed [n]<\/td>\n4800 rpm<\/td>\n<\/tr>\n
Rotational Inertia<\/td>\n0.103 kg\u00b7m\u00b2<\/td>\n<\/tr>\n
Mass (approx.)<\/td>\n27.5 kg<\/td>\n<\/tr>\n
Material<\/td>\nCast Iron (HT200) standard; cast steel available<\/td>\n<\/tr>\n
Bore Type<\/td>\nY-type, J-type, or tapered bore<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

GY, GYS and GYH Subtype Dimension Reference<\/h2>\n

\"GY<\/p>\n

Three Subtype Comparison<\/h2>\n
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GY Type \u2013 Hinge Bolt<\/h3>\n

The standard GY type uses a hinge bolt hole system. Assembly and disassembly are performed by removing the flange bolts \u2014 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.<\/p>\n<\/div>\n

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GYS Type \u2013 Alignment Boss<\/h3>\n

GYS type adds a precision alignment boss (\u51f8\u6954) 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.<\/p>\n<\/div>\n

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GYH Type \u2013 Ring Design<\/h3>\n

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.<\/p>\n<\/div>\n

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Zero Backlash \u2013 All Subtypes<\/h3>\n

All three GY subtypes transmit torque through rigid bolted flange joints and key-keyway shaft connections \u2014 providing absolute zero backlash. The rated 3150 N\u00b7m and 4800 rpm apply equally to GY, GYS, and GYH configurations.<\/p>\n<\/div>\n<\/div>\n

Manufacturing Quality<\/h2>\n

\"Ever<\/p>\n

Typical Applications<\/h2>\n