Large-Diameter Ring Gear Enables Low-Speed, High-Torque Output High Precision and Smooth Transmission

1. Introduction
A Large-Diameter Ring Gear is an annular gear component with an outer diameter typically exceeding 1 meter, and can reach up to tens of meters. It is often not manufactured as a single solid gear but is constructed from multiple segmented gear rim sections. These segments are bolted together using high-strength bolts to form a complete ring, which is then mounted onto the main body of large equipment (e.g., a drum, turntable). Its core function is to transmit power and motion to a mating pinion gear, enabling the low-speed, heavy-duty, high-torque rotation of large slewing devices. It serves as the "critical transmission joint" in numerous heavy-duty equipment.

2. Advantages

• Extreme Load Capacity: Designed specifically to transmit enormous torque and withstand heavy loads, making it a core component for heavy-duty drive applications.

• Enables Low-Speed, High-Torque Output: Through meshing with a smaller pinion, it creates a large reduction ratio, converting high-speed, low-torque input into low-speed, high-torque output to drive large equipment slowly and powerfully.

• Modular Design and Cost-Effectiveness: The segmented design overcomes the immense challenges associated with casting, forging, heat treatment, machining, and transportation of ultra-large single pieces, lowering manufacturing barriers and overall costs.

• Flexible Installation and Easy Maintenance: Segmented ring gears can be assembled on-site, eliminating the need for massive machining equipment. Individual segments can be replaced if worn or damaged, significantly reducing maintenance costs and downtime.

• High Precision and Smooth Transmission: Advanced machining techniques (e.g., CNC profile grinding) allow for high accuracy grades, ensuring smooth operation, low noise, and long service life.

3. Key Technical Parameters

• Diameter: The key dimension, ranging from 1 meter to over 2 meters.

• Module / Diametral Pitch: The key parameter determining tooth size. Large ring gears typically feature large modules (e.g., Module 10 up to 100+).

• Accuracy Grade: Rated according to ISO or AGMA standards (e.g., ISO 1328 Class 6, 7, 8), affecting transmission smoothness and noise.

• Tooth Profile: Usually an involute profile. Modifications (profile shifting, crowning) are often applied to optimize load distribution and compensate for deflection.

• Material & Heat Treatment: Commonly made from high-quality alloy steels like 42CrMo, 42CrNiMo. The tooth flanks are usually hardened (e.g., induction hardening, carburizing) for wear resistance, while the core remains tough.

• Mounting Type: Flange connection, bolted connection, shrink-fit assembly, etc.

4. Applications
Large-diameter ring gears are critical components in numerous large-scale rotary equipment, widely used in:

• Mining and Metallurgy: Ball mills, rotary kilns, sintering machines, bucket-wheel excavators.

• Energy and Power Generation: Wind turbine generators (yaw and pitch drive ring gears), coal pulverizers in thermal power plants.

• Construction Machinery: Slewing mechanisms of tower cranes, excavator slewing platforms.

• Defense and Marine: Radar bases, naval gun turntables, shipboard cranes.

• Others: Drive mechanisms for large astronomical telescopes, large rotating stages.