Internal Gear (Ring Gear)
Internal Gears for Planetary Systems
We are specialists in manufacturing high-precision internal ring gears, the essential component for creating compact and efficient planetary gear drives.
- Key Component for Planetary Gearboxes
- Enables Compact, High-Ratio Drives
- Smooth & Quiet Operation
- Manufactured via Precision Shaping
Manufacturing Capabilities
We leverage specialized gear shaping and internal grinding technology to produce internal ring gears that meet the stringent demands of modern power transmission systems.
| Gear Type | Internal Gear / Ring Gear |
| Tooth Form | Spur (Standard), Helical (On Request) |
| Module Range | 1 to 10 Module |
| Maximum Diameter | Up to 1000mm |
| Manufacturing Process | Precision Gear Shaping, Broaching, Internal Teeth Grinding |
| Materials | Alloy Steels (EN24, EN353, 20MnCr5, SAE 8620), Carbon Steels |
| Heat Treatment | Case Carburizing & Hardening, Nitriding, Through Hardening |
| Accuracy Standards | Manufactured to AGMA, DIN, and ISO quality standards |
Common Industrial Applications
Internal gears are fundamental to machinery where high torque, significant speed reduction, and a compact footprint are required:
- Planetary Gearboxes for Industrial Machinery
- Automatic Transmissions for Vehicles
- Heavy-Duty Hoist and Winch Drives
- Machine Tool Indexing Heads and Turrets
- Robotic Arm Joints and Actuators
- Construction Equipment Drives (e.g., excavators)
- Wind Turbine Gearboxes
- Hydraulic Gear Pumps
Understanding Internal Gear Terminology
The unique geometry of internal gears introduces specific terms essential for their design and application.
| Term | Definition in Internal Gearing |
|---|---|
| Ring Gear | The common name for an internal gear, especially when it acts as the outer, stationary, or rotating ring in a planetary system. |
| Planetary System | A gear train consisting of a central 'sun' gear, multiple 'planet' gears revolving around it, and an outer 'ring' gear. |
| Contact Ratio | The average number of teeth in contact at any given time. Internal gears have a higher contact ratio, leading to smoother power flow and lower noise. |
| Same Direction Rotation | Unlike external gears, an internal gear and its meshing external pinion rotate in the same direction. |
| Interference | A design constraint where the tips of the pinion and internal gear teeth collide during meshing. Must be avoided by careful design, especially when tooth counts are close. |
The Power of the Planetary System
The true strength of an internal gear is realized in a planetary (or epicyclic) gear train. By having multiple planet gears meshing with both the central sun gear and the outer ring gear, the load is distributed among several contact points. This allows for the transmission of very high torque in an incredibly compact physical envelope, a feat that would require much larger and heavier gears in a conventional parallel-axis arrangement.
Frequently Asked Questions
The primary advantage is compactness. An internal gear allows for the creation of high-ratio gear reductions in a very small space, which is why it's the foundation of planetary gearboxes. They also offer a higher contact ratio, leading to smoother and quieter operation compared to an equivalent external gear set.
Gear hobbing uses a large, screw-like cutter (a hob) that needs significant clearance to work. It's physically impossible to fit a hob inside a gear blank to cut internal teeth. Gear shaping uses a smaller, pinion-shaped cutter with a reciprocating motion, which can easily operate inside the ring to generate the internal tooth profile.
They rotate in the SAME direction. This is a key difference from a standard external gear pair, where the two gears always rotate in opposite directions.
The Shreeji Gears Internal Gear Advantage
Our specialized manufacturing delivers the precision required for high-performance drives.
Planetary System Expertise
We understand the critical role the ring gear plays in a planetary system. We manufacture internal gears with the profile accuracy and concentricity needed for proper load sharing between planets.
Advanced Gear Shaping
Manufacturing internal gears requires specialized technology. Our precision gear shaping machines can create complex internal tooth profiles with exceptional accuracy, ensuring a perfect mesh and smooth operation.
Heat Treatment for Durability
Internal gears in planetary drives are subject to high stress. Our controlled heat treatment processes, like case carburizing or nitriding, create a hard, wear-resistant surface with a tough core to withstand demanding cycles.
How a Planetary Gear System Works
The internal gear is the key that unlocks this powerful mechanism.
The Three Core Components
A planetary gearset consists of three main elements working together:
- The Sun Gear: The central gear, typically connected to the input shaft (e.g., from a motor).
- The Planet Gears & Carrier: Multiple smaller gears that mesh with the sun gear. They are mounted on a movable frame called the planet carrier.
- The Ring Gear (Internal Gear): The outer ring with internal teeth, which meshes with the planet gears.
By holding one of these three components stationary and using another as the input, the third component becomes the output. This versatility allows for significant speed reductions or increases in a very compact design. The internal ring gear is essential as it constrains the planet gears and allows for the load to be distributed among them, enabling high torque capacity.
"The internal gears we sourced from Shreeji Gears for our winch drive systems were flawless. The dimensional accuracy and heat treatment quality were exactly to our specifications, leading to improved reliability in the field."— Head of Procurement, Heavy Equipment Manufacturer
Get a Quote for Your Internal Gear
Provide your specifications for a competitive, no-obligation quote.
For the fastest service, please email your technical drawing to support@shreejigears.com. A drawing is highly recommended for internal gears due to their complexity.
- Number of Teeth
- Module or Diametral Pitch (DP)
- Pressure Angle
- Face Width & Overall Blank Dimensions
- Material & Required Hardness
- Accuracy Class Required (e.g., AGMA 8, DIN 9)
- Required Quantity