Heavy Planetary Carrier and Large Format Transmission Components — Precision Machined to Customer Drawing

SMI manufactures heavy planetary carriers and large format transmission components to customer drawing and technical specification — covering planet carriers, ring gears, output flanges and gear shaft assemblies at weights and dimensions beyond the envelope of standard industrial reducer supply. The planet carrier shown below — Φ680 × 620mm, 810KG — is representative of the scale and precision machining capability SMI applies to heavy transmission component supply.

Every component in this category is produced to the customer’s own engineering drawing. Material grade, dimensional tolerances, heat treatment specification, surface finish and inspection requirements are all defined by the customer’s design — SMI’s role is to manufacture to that specification with the casting, forging and precision machining capability required to achieve it consistently.

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Representative Component — Planet Carrier Φ680 × 620mm, 810KG

The planet carrier is the most structurally demanding component in a planetary transmission system. It carries the full output torque of the reducer, supports the planet gear bearing loads on all pin positions simultaneously, and must maintain precise dimensional relationships between pin bores across its full service life under cyclic loading.

At Φ680 × 620mm and 810KG, the component shown represents a transmission system capable of handling several thousand kilowatts of input power — consistent with the drive system requirements of energy drilling equipment, large ball mills, tunnel boring machine cutter head drives and heavy marine lifting machinery. Key manufacturing requirements for a component at this scale include:

• Casting integrity — at 810KG, internal soundness of the casting is critical. Any porosity or inclusion concentration at the hub or pin boss locations will initiate fatigue cracking under the cyclic torque loads of heavy drive service. SMI’s casting practice for heavy components includes controlled pouring, riser design and post-casting inspection to verify internal quality before machining begins
• Pin bore positional accuracy — the angular and radial position of each planet pin bore determines the load sharing between planet gears. Positional error concentrates load on individual planets and reduces the effective torque capacity of the assembly. SMI machines pin bores to the positional tolerances specified in the customer’s drawing, verified by CMM inspection
• Hub bore concentricity — the central hub bore carries the output shaft or sun gear shaft bearing. Concentricity relative to the pin bore pitch circle is machined and verified to drawing tolerance
• Flange face flatness and bolt circle accuracy — the output flange face and bolt circle are machined to the assembly tolerances required for correct mating with the adjacent shaft or housing component

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Heavy Transmission Component Range

Planet Carriers

Cast steel planet carriers from small industrial sizes up to 810KG and above — machined to customer drawing for single-stage and multi-stage planetary systems. Hub bore, pin bore positions, flange face and bolt circle all machined to drawing tolerance. CMM dimensional verification as standard on large format components.

Internal Ring Gears

Large format internal ring gears — cast or forged blanks, internal gear cut to specified module, tooth profile accuracy grade and face width. Heat treatment to specified surface hardness. Ring gear housing bore and mounting features machined to assembly drawing. Available in through-hardened and case-hardened configurations to customer specification.

Output Flanges and Carrier Flanges

Heavy output flanges and carrier flanges — precision machined bolt circle, mating face flatness and bore dimensions to assembly drawing tolerances. Flange face machining to the surface finish specified for the sealing or mating interface requirements of the customer’s application.

Planet Gear Shaft Assemblies

Planet gear shaft assemblies — external gear cutting to specified module and accuracy grade, shaft journal machining to bearing fit dimensions, spline features to customer profile specification. Heat treatment and surface finish to drawing. Available as individual components or as matched sets for a complete planet gear stage.

Sun Gears and Input Shaft Assemblies

Sun gear and input shaft assemblies — external gear cutting, journal machining and spline or coupling features to customer drawing. Case hardening or nitriding to specified surface hardness and case depth. Balanced to customer requirement for high-speed input shaft applications.

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Application Sectors

Energy and Drilling Equipment

Heavy planetary transmission components for the drive systems of energy drilling and production equipment — including drawworks transmission systems, mud pump drives and rotary table drives for oil and gas drilling applications. These applications demand high torque density, resistance to shock loading and consistent dimensional accuracy across the full component set to ensure reliable operation under the demanding conditions of drilling service.

Mining and Mineral Processing

Large format planet carriers, ring gears and output flanges for ball mill drives, SAG mill drives, crusher drives and mine hoist transmission systems. Mill drive planetary systems operate continuously under high torque and are subject to the cyclic shock loads generated by the grinding charge — requiring casting integrity and dimensional accuracy that SMI’s heavy component manufacturing capability is designed to deliver.

Tunnelling and Construction Machinery

Heavy planetary transmission components for cutter head drive systems and large crawler crane travel drives. Cutter head planetary systems operate under extreme and variable load conditions — requiring robust casting design, controlled heat treatment and precise pin bore geometry to maintain load sharing across all planet positions throughout the service life of the drive.

Marine and Offshore Lifting

Planet carriers and ring gears for ship deck machinery, heavy lift crane slewing and hoisting drives, and offshore winch transmission systems. Marine applications require material certification to classification society standards — available on request from SMI.

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Manufacturing Capability

Operation	Capability
Casting	Cast steel planet carriers and housings — weight from small industrial to 810KG and above
Forging	Forged blanks for ring gears, sun gears and shaft components where mechanical property requirements exceed cast steel capability
Turning and boring	Large format CNC turning and boring — hub bores, flange faces and journal diameters to drawing tolerance
Gear cutting	Internal and external gear cutting — module, tooth profile and accuracy grade to customer specification
Pin bore machining	Positional accuracy to customer drawing — CMM verification on large format planet carriers
Heat treatment	Through hardening, case hardening and nitriding to specified surface hardness and case depth
Inspection	CMM dimensional inspection, hardness verification, material certification — standard on heavy components

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بالعربية — ناقلات الكواكب الثقيلة ومكونات نقل الحركة كبيرة الحجم

تقوم SMI بتصنيع ناقلات الكواكب الثقيلة ومكونات نقل الحركة كبيرة الحجم وفقاً لرسومات العملاء والمواصفات التقنية — تشمل ناقلات الكواكب، التروس الحلقية الداخلية، الشفاه الإخراجية، ومجموعات أعمدة التروس الكوكبية بأوزان وأبعاد تتجاوز النطاق المعياري. ناقل الكواكب الممثل: Φ680 × 620مم، 810 كجم. قطاعات التطبيق: معدات الحفر، مطاحن التعدين، آلات حفر الأنفاق، والرافعات البحرية الثقيلة. للاستفسار، تواصل مع فريق SMI →

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En Español — Portasatélites Pesados y Componentes de Transmisión de Gran Formato

SMI fabrica portasatélites pesados y componentes de transmisión de gran formato según los planos y especificaciones técnicas del cliente — incluyendo portasatélites, coronas internas, bridas de salida y conjuntos de ejes de engranajes planetarios con pesos y dimensiones que superan el rango estándar. Portasatélite representativo: Φ680 × 620mm, 810KG. Sectores de aplicación: equipos de perforación energética, molinos de minería, maquinaria de tunelización y sistemas de elevación marina pesada. Para consultas, contacte al equipo de SMI →

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Auf Deutsch — Schwere Planetenträger und Großformat-Getriebekomponenten

SMI fertigt schwere Planetenträger und Großformat-Getriebekomponenten nach Kundenzeichnung und technischer Spezifikation — einschließlich Planetenträger, Hohlräder, Ausgangsflansche und Planetenradwellenbaugruppen mit Gewichten und Abmessungen jenseits des Standardbereichs. Repräsentativer Planetenträger: Φ680 × 620mm, 810KG. Anwendungsbereiche: Energiebohrausrüstung, Bergbaumulühlen, Tunnelbohrmaschinen und schwere Marinehubsysteme. Für Anfragen, kontaktieren Sie das SMI-Team →

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Related Products — SMI Transmission & Drive Systems

• Planetary Reducer — Industrial and Agricultural Series — standard range to 2,000 N.m, ratio 3:1 to 400:1
• Agriculture Gearbox Design and Manufacturing — rotary mower gearbox series
• PTO Shaft and Power Take-Off Components — agricultural driveline supply
• Contact SMI — Heavy Transmission Component Enquiry →

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Request a Consultation

To discuss heavy planetary carrier or large format transmission component requirements, please provide the following at enquiry stage:

• Component type — planet carrier, ring gear, output flange, gear shaft or complete stage
• Key dimensions — outer diameter, height, hub bore diameter, approximate weight
• Material specification — steel grade, heat treatment and mechanical property requirements
• Gear data — module, number of teeth, accuracy grade (for ring gears and gear shafts)
• Pin bore data — number of planets, pin bore diameter, positional tolerance (for planet carriers)
• Application — equipment type and operating conditions
• Inspection and certification requirements — CMM report, material cert, classification society if applicable
• Drawing or 3D model if available

SMI will respond with a written technical assessment and commercial proposal. Contact SMI — Heavy Transmission Component Enquiry →