Inline Planetary Gearbox
DETAILS:
Inline Planetary Gearbox is one of the main products manufactured by Sango Automation, which is one of the earliest professional manufacturers in mainland China.
With years of dedicated engineering effort and deep technical accumulation, Sango Automation has established itself as the premier manufacturer of globoidal and coaxial Inline Planetary Gearboxes across the automation industry.
Sango Automation Limited is one of the most reliable manufacturers and suppliers of 2 stage planetary gearbox in China. With abundant experience, we warmly welcome you to wholesale advanced 2 stage planetary gearbox made in China here from our factory. Good service and quality products are available.
Product Overview
A 2 stage planetary gearbox - also referred to as a two-stage planetary gear reducer - achieves speed reduction and torque multiplication through two consecutive planetary gear sets arranged in series.
Compared to single- and three-stage planetary gearboxes, the two-stage planetary gearbox can raise the reduction ratio to 100:1 without significantly increasing axial length, avoiding a significant drop in transmission efficiency (a two-stage planetary gearbox typically ≥ 94%). This balance between "reduction ratio, efficiency, and compactness" makes the two-stage planetary gearbox widely used in robotic joint actuators and industrial automation equipment.
As a manufacturer of precision transmission components, Sango offers small-batch custom production (OEM/build-to-print) based on your drawings. If you are seeking a reliable manufacturing partner for 2-stage planetary gearboxes-whether for robot joints, servo axes, or automation equipment-please feel free to send your drawings or specifications to request a quote.
How It Works
Limitations of Single-Stage Planetary Gearboxes
Single-stage planetary gearboxes are typically limited to reduction ratios up to 10:1. Attempting higher single-stage ratios requires larger ring gears and smaller sun gears, which compromises mechanical strength and tooth contact area.
Transmission Logic of a Two-Stage Series Configuration
In a two-stage configuration, the output carrier of the first planetary stage directly drives the sun gear of the second stage. This multiplies the individual reduction ratios for up to 100:1 overall reduction.
High Efficiency & Torque Multiplication
By utilizing two high-efficiency planetary gear stages (each >97% efficient), the combined system maintains over 94% overall efficiency while generating massive torque multiplication.
Significance of the Fixed Ring Gear
Both planetary gear stages share a common internal ring gear fixed within the housing. As the sun gear rotates, the planet gears orbit inside the ring gear, transmitting smooth, high-rigidity output motion.
Technical Parameters
| Parameter | Value / Range | Note |
|---|---|---|
| Axis relationships | Coaxial (Inline input & output axes) | Input & output shafts are collinear |
| Reduction ratio range | 15:1 to 100:1 (2-stage series) | Single-stage 3:1 to 10:1 also available |
| Transmission efficiency | ≥ 94% (Full load duty) | Single-stage efficiency ≥ 97% |
| Backlash precision grades | P0 (<1 arcmin) / P1 (<3 arcmin) / P2 (<5 arcmin) | Laser interferometry verified |
| Rated output torque | 15 N·m to 2,500 N·m | Emergency stop torque up to 300% nominal |
| Input speed rating | 3,000 RPM (Nominal) to 10,000 RPM (Max) | Dynamic balanced split-collar coupling |
| Torsional stiffness | 12 to 60 N·m/arcmin | High-rigidity planet carrier architecture |
| Protection rating & Lube | IP65 / IP67 · Synthetic PAO / Food Grade | Permanent factory lubrication (20,000h) |
All specifications apply to OEM / custom-drawing orders. Final tolerances are confirmed against the customer's drawing prior to production. Contact us with your drawing or target specifications for a detailed manufacturing assessment.
Manufacturing Capabilities
Our gear manufacturing capabilities encompass spur gears, helical gears, bevel gears (including spiral bevel gears), and internal gear rings, with a module range of 0.1-5.0, tip diameters of 3-300 mm, and precision levels reaching up to ISO Class 5.
Regarding equipment, the Kashifuji KPS30 is a high-precision Japanese CNC skiving machine ideal for the high-precision cutting of planetary and sun gears used in planetary reducers; Gleason CNC gear cutting machines are dedicated to the production of hypoid and spiral bevel gears; and four-axis whirling machines handle both rough and finish machining for bevel gears. In terms of heat treatment, induction hardening allows for localized hardening of gear tooth surfaces, increasing surface hardness to withstand high contact stresses while maintaining core toughness; phosphating enhances break-in performance and rust resistance, making it ideal for parts requiring long-term storage.
Precision Parts Processing Line
Precision Parts Processing Line
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Application Scenarios & Selection Guide
Consider the scenarios of robot joints and AGV drives: while both utilize two-stage planetary structures, their design priorities differ significantly. Robot joints demand extremely low backlash (P1/P0 classes) and high axial compactness, whereas AGV drive wheels prioritize continuous load-bearing capacity and load sharing among multiple planetary gears, for which P2-class backlash is typically sufficient.
Among these applications, robot joint actuators have seen the most significant growth in demand over the past two years. Joint drive modules for humanoid robots and quadruped robots typically feature a high level of integration, housing a two-stage planetary gearbox, frameless torque motor, encoder, and crossed-roller bearings within a single unit. The ring gear is integrated directly into the motor housing; consequently, the housing's coaxiality and bore precision directly impact the gearbox's assembly clearance and operating noise. Additionally, the shaft connecting the two planetary carrier stages must ensure sufficient rigidity within a very limited axial space.
If your application requires a gear ratio between 10:1 and 100:1, involves strict volume constraints, and necessitates direct coupling with a servo motor, a two-stage planetary gearbox is likely the optimal solution. For ratios exceeding 100:1, a three-stage planetary setup or a combination with a harmonic drive may be considered; conversely, if the ratio is below 10:1 and precision requirements are extremely high, a single-stage planetary or direct-drive solution might be more appropriate.
Customization Process
Our collaborative customization process ensures your custom gearbox is optimized for both performance and manufacturability. Here is how we work together from drawing to mass production.
Steps
Preliminary Consultation & NDA Signing
To protect your IP, we first sign a mutual NDA. Then, we align technically and review your 2D/3D drawings, specifications, interface requirements, and envelope constraints.
DFM Analysis & Design Optimization
Our motion engineers perform tooth strength analysis, ratio verification, and DFM optimization to ensure peak torque density, low backlash, and efficient production.
Prototyping & Rapid Manufacturing
Using high-precision CNC gear skiving and Gleason cutting machines, we manufacture initial prototypes for form, fit, and functional testing.
Metrology Testing & Quality Validation
Every prototype undergoes 3D CMM metrology inspection, backlash measurements, and run-in efficiency verification on dynamic test benches.
Batch Production & On-Schedule Fulfillment
Upon prototype sign-off, we initiate volume manufacturing with complete material test reports (MTRs) and guaranteed on-time delivery.
What Type of Device Could Use Planetary Gearbox
The Planetary Gearbox could be applied for many applications like CNC Indexing Device, Rotating Stage, Electronic component assembly machines, medical capsule production machine, packing machine, plaster container manufacturing equipment, food filling and wrapping machines, various assembly and inspection machines.
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