Driving industrial power with precision: SGR’s classic 3-stage planetary gearbox

In heavy industries such as mining, metallurgy, construction, and textile manufacturing, machinery must withstand extreme loads, operate continuously, and deliver precise, efficient performance. At the heart of these machines lies a crucial component—the gearbox. For applications requiring high torque, compact size, and superior reliability, the 3-stage planetary gearbox has become the preferred choice worldwide.

SGR (Shanghai SGR Heavy Machinery Co., Ltd.), with over 15 years of expertise in mechanical transmission, has developed a classic 3-stage planetary gearbox that has set benchmarks in China and abroad.

Designed with cutting-edge technology, manufactured to international standards, and optimized for cost-effectiveness, SGR’s planetary gearbox is not only widely adopted but has also earned accolades, including the First Prize for Scientific and Technological Achievements in the Gear Industry from the China Gear Association.

(1) What is a 3-stage planetary gearbox?

A planetary gearbox is a compact, high-torque transmission system where multiple gears—known as planet gears—rotate around a central sun gear while meshing with an outer ring gear. This arrangement ensures multiple teeth are engaged simultaneously, allowing the gearbox to transmit heavy loads with superior efficiency compared to traditional gear systems.

In a 3-stage planetary gearbox, three sets of planetary gear trains are connected in sequence. Each stage reduces speed and multiplies torque, enabling the gearbox to achieve extremely high transmission ratios while maintaining a compact structure. This makes the 3-stage planetary gearbox especially suitable for industries where:

High torque and compact design are critical,Continuous, stable operation is required,Precision and efficiency translate directly to productivity.

(2) The unique advantages of SGR’s 3-stage planetary gearbox

SGR has refined planetary gearbox design with a focus on durability, efficiency, and reliability. The company’s classic 3-stage planetary gearbox stands out in the industry for several reasons:

1. Superior material and heat Treatment

The gears are made from 20CrMnTi alloy steel, a premium-grade material well-suited for high-load applications. Each gear undergoes a carburizing and quenching process, followed by precision grinding. This ensures high surface hardness for wear resistance,strong core toughness to resist impact loads,smooth gear meshing for reduced noise and vibration.

2. Load distribution through multiple Teeth

Unlike conventional gear systems, SGR’s planetary gearbox engages several teeth simultaneously. This allows the load to be evenly distributed across multiple contact points, leading to higher load-bearing capacity,extended service life of gears,smooth, reliable operation even under shock loads.

3. High mechanical efficiency

Through optimized gear design and precision grinding, the gearbox achieves efficiency levels above 95%, significantly reducing energy loss in transmission and lowering operating costs.

4. Compact structure with high power density

Despite its high torque output, the 3-stage planetary gearbox is remarkably compact. This allows OEMs and end-users to design more space-efficient machinery without compromising performance.

5. Proven reliability in harsh conditions

The gearbox is engineered for industries that operate under demanding conditions, such as heavy dust in mining or high thermal loads in metallurgical plants. Its durability and reliability minimize downtime and maintenance costs.

6. Recognition and market acceptance

In 2009, the 3-stage planetary gearboxes won the First Prize for Scientific and Technological Achievements in the Gear Industry and was recognized as a Shanghai High-Tech Achievement Transformation Project，and they was supported by an invention patent application, demonstrating innovation leadership.

The 3-stage planetary gearboxes were adopted by users across construction machinery, marine auxiliary machinery, mining, textile, and printing and dyeing industries.

(3) Application Spotlight: SGR’s 3-stage planetary gearbox in Inner Mongolia metallurgical machinery

One of the most compelling demonstrations of SGR’s planetary gearbox technology comes from its deployment in metallurgical machinery in Inner Mongolia, a region known for its large-scale steel and alloy production.

Metallurgical machinery must handle continuous heavy loads, operate in high-temperature environments, and deliver precise, reliable motion control. In Inner Mongolia’s steel plants, equipment such as rolling mills, lifting systems, and conveyor drives face tremendous stress. Traditional gearboxes often fall short in terms of durability and efficiency, leading to costly downtime.

To address these challenges, SGR supplied its classic 3-stage planetary gearboxes for key metallurgical machinery systems. The application highlighted several product advantages:

• Torque Amplification for Rolling Mills:The gearbox delivered high torque in a compact structure, enabling rolling equipment to process large steel billets with smooth and reliable operation.
• High Efficiency for Continuous Production:The >95% transmission efficiency reduced power consumption and improved energy utilization across the plant.
• Durability Under Harsh Conditions:With 20CrMnTi carburized and ground gears, the gearbox demonstrated excellent wear resistance despite exposure to dust, vibration, and heavy load cycles.
• Reduced Maintenance Costs:Thanks to the gearbox’s robust design and reliable operation, the plant reported significant reductions in maintenance downtime and spare parts consumption.

After long-term operation in Inner Mongolia’s metallurgical plants, SGR’s planetary gearboxes received high praise from operators and engineers. The gearboxes not only met but exceeded expectations in terms of stability and longevity. Importantly, the cost-effectiveness of SGR’s localized service model provided additional value compared to imported alternatives, helping the plant achieve better return on investment.

The success of this application demonstrated that domestically produced, high-performance planetary gearboxes can compete with international brands in critical heavy industries. It reinforced SGR’s reputation as a trusted, technologically advanced gearbox manufacturer in China and beyond.

To conclude,SGR’s classic 3-stage planetary gearbox is more than just a transmission component—it is a critical enabler of efficiency, reliability, and innovation across multiple industries. With advanced materials, precise heat treatment, high mechanical efficiency, and proven performance in demanding applications like Inner Mongolia’s metallurgical machinery, SGR continues to deliver value that balances international standards with localized cost advantages.

For users seeking a gearbox solution that combines technical excellence, durability, and cost-effectiveness, SGR’s planetary gearbox stands as the optimal choice. With over 15 years of expertise, industry recognition, and a strong record of field applications, SGR is committed to driving industrial power with precision and reliability—today and into the future.（Author: SGR, Angie Zhang）

Email: export@sgr.com.cn

WhatsApp: +86 188 1807 0282

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