Precision internal ring gear with internal teeth for planetary gearboxes by Weforging
internal ring gear assembly for slewing bearings and planetary gearboxes – Weforging
Internal gear ring with machined involute teeth for power transmission

Forged Ring Gear Manufacturer | Custom Internal Ring Gears

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Forged Internal Ring Gear for Planetary Gearboxes

The internal ring gear plays a critical role in modern power transmission systems, delivering smooth torque transfer, accurate meshing performance, and long-term durability. Manufactured through ring rolling forging and precision CNC machining, Weforging’s internal ring gears are engineered to meet demanding requirements in planetary gearboxes, construction machinery, industrial reducers, and automotive applications. With optimized mechanical strength and excellent dimensional stability, each gear ring supports reliable operation even in high-load or continuous-duty environments.

Precision internal ring gear with internal teeth for planetary gearboxes by Weforging

What Is an Internal Ring Gear?

An internal ring gear features involute teeth on the inner circumference, allowing pinions or planetary gears to engage from inside. Compared with external gears, internal gears offer:

  • More compact gearbox design

  • Lower sliding friction

  • Reduced noise due to opposite-direction meshing

  • Improved load distribution in planetary systems

Internal ring gears are widely used in planetary gear trains, hydraulic motors, slewing drives, and precision transmission assemblies.

Advanced Manufacturing Process

Weforging produces internal ring gears through a controlled process:

1. Ring Rolling Forging
Forms the ring with dense structure and optimized grain flow.

2. Heat Treatment
Quenching & tempering or carburizing improves hardness and wear resistance.

3. CNC Machining
Ensures accurate dimensions, bore finishing, and runout control.

4. Gear Tooth Cutting
Shaping or broaching achieves precise tooth profile and smooth meshing.

5. Finishing & Inspection
Final machining and inspection ensure consistent quality and reliable performance.

Key Specifications of Forged Internal Ring Gear

ItemSpecification
Outer Diameter200 – 2500 mm
Module RangeM2 – M30
Accuracy GradeISO 1328: Grade 6 – 9
Material42CrMo / 4140 / 20CrMnTi / 8620
Heat TreatmentQuenching & Tempering / Carburizing
HardnessHRC 28 – 62
ManufacturingRing Rolling + CNC Machining

Material Options

Internal ring gears can be produced from multiple high-performance steels, including:

  • 42CrMo / SCM440 – high strength, excellent toughness

  • 40Cr / 4140 – widely used for gear applications

  • 20CrMnTi / 8620 – ideal for carburizing and wear-resistant gears

  • S355 / Q345 – general-purpose gear rings

  • Custom stainless and alloy steels upon request

Key Performance Advantages

Weforging’s forged internal ring gears offer:

  • High load capacity enabled by dense forged structure

  • Excellent wear resistance through heat treatment

  • Smooth, accurate meshing with optimized involute profiles

  • Long service life due to superior mechanical properties

  • Reliable performance under continuous or high-speed conditions

These advantages make our internal ring gears suitable for rigorous industrial environments.

Applications

Our forged internal ring gears are widely used in:

  • Planetary gearboxes for construction machinery

  • Industrial reducers and servo drives

  • Excavators, loaders, and cranes slewing & travel systems

  • Agricultural machinery powertrains

  • Electric motors and hydraulic motors

  • Robotics and automated machinery

Whether for high-precision motion control or heavy-duty torque transfer, Weforging delivers stable and reliable ring gears tailored to your needs.

Quality Assurance

Each gear undergoes strict testing:

  • Dimensional inspection

  • Hardness measurement

  • Tooth profile and pitch accuracy checks

  • Magnetic particle / ultrasonic testing (optional)

This ensures consistent performance and long-term reliability.

Contact & Customization

Weforging provides standard and fully customized internal ring gears. If you need tailored materials, tooth modules, heat-treatment profiles, or machining tolerances, our engineering team is ready to assist.

Contact us today to request drawings, quotations, or technical consultation.

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What is an internal ring gear used for?

An internal ring gear is mainly used in planetary gearboxes to transmit torque efficiently within a compact design. It enables smooth power transfer, high load capacity, and stable performance in heavy-duty applications such as construction machinery, industrial reducers, and wind power systems.

What is the difference between an internal ring gear and an external gear?

An internal ring gear has teeth on the inner circumference, while an external gear has teeth on the outside. Internal gears are commonly used in planetary systems because they allow more compact design, lower noise, and improved load distribution during operation.

How are forged internal ring gears manufactured?

Forged internal ring gears are produced through ring rolling forging, followed by heat treatment and precision CNC machining. This process ensures a seamless structure, high dimensional accuracy, and consistent gear performance suitable for demanding industrial applications.

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