Small‑size BLDC Planetary Geared Motor Options

In the field of micro precision transmission equipment, conventional brushed motors are limited by carbon‑brush wear, short service life and poor speed consistency, failing to meet high‑end equipment requirements for long‑term operation, low noise and precise positioning. Integrated custom modules of BLDC motor plus planetary gearbox are currently the mainstream upgrade solution in the industry.

Compared with standard off‑the‑shelf motors, custom BLDC planetary geared motors can be tailored for equipment mounting space, torque requirements, positioning accuracy, control modes and service life. Huajuntong Motor offers five widely‑used outer‑diameter models: 12mm, 16mm, 24mm, 28mm and 36mm. We deliver ready‑to‑implement custom selection solutions covering four core dimensions: gear processing, backlash, drive control and optional encoders.

I. Outer Diameter Sizing Logic (Standard Sizes for Full‑range Micro‑device Coverage)

All our BLDC planetary geared motors adopt industry‑standard outer diameters: 12mm, 16mm, 24mm, 28mm and 36mm. With progressively increasing sizes, they fit different torque levels and mounting spaces. Featuring proven mechanical structures, the full product line supports multi‑stage planetary reduction. Speed ratios, output shaft configurations and wiring types can be flexibly adjusted without customer re‑tooling, greatly reducing new‑product R&D costs.

Size Classification: 12/16 mm for precision equipment with ultra‑compact space; 24/28 mm as general‑purpose medium‑torque mainstream models; 36 mm for heavy‑load, high‑torque and long‑duration continuous‑operation scenarios. Fully applicable to consumer electronics, smart home, precision medical devices, small‑sized automation equipment, smart gimbals and other industries.

II. Customization of Gear Technology & Backlash (Core for Precision Grading)

Precision differences of micro planetary geared motors mainly stem from gear machining processes, which serve as key differentiators for customer customization. Mass‑production gears are available in two versions: powder‑metallurgy molded gears and precision‑machined gears. They deliver distinct performance in torque, service life and backlash level for clearly‑defined working conditions.

1、Powder Metallurgy Molded Gears (General‑purpose Economy Grade)

Adopting one‑step forming powder metallurgy process, it features low mass‑production cost and stable consistency, suitable for high‑volume products. Gear forming accuracy meets general industry standards with reasonable tolerance for tooth clearance and relatively large backlash.

Application Scenarios: Equipment without high‑precision positioning requirement, low‑frequency forward‑reverse rotation and regular constant‑speed transmission. Featuring reliable durability and cost‑effectiveness, it satisfies most civilian‑grade micro‑transmission demands and is the most widely‑adopted mass‑production solution on the market.

2、Precision‑Machined Gears (High‑Precision & Low‑Backlash)

Manufactured by CNC turning, gear hobbing and chamfering finishing processes, these gears feature high tooth‑profile fitting and minimal meshing clearance. Backlash can be controlled within 1°, eliminating dead zone during forward‑reverse switching for accurate positioning and greatly improved running smoothness. Higher tooth‑surface strength delivers better shock resistance and wear resistance with minor precision degradation over long‑term operation, offering much longer service life than molded gears.

Application Scenarios: Mid‑to‑high‑end equipment requiring precise angular positioning, high‑frequency forward‑reverse rotation, fine adjustment and servo linkage. It is the preferred solution for precision automation, medical devices and intelligent optical adjustment mechanisms.

III. Customization of Three Electronic Control & Drive Solutions

Unlike brushed motors, BLDC motors cannot run by direct power supply and require matching drive control structures. Based on customer control requirements, we provide three standardized wiring solutions with progressively upgraded functions. Customers may select directly according to their main‑board capability without secondary development.

1、3‑Wire Bare Motor Solution (No Built‑in Driver)

Only three phase wires are led out from the motor, with no built‑in control board or Hall board. It features minimal structure, compact size and low cost.

Features: No speed regulation, positioning or voltage stabilization functions. Customer’s mainboard must be equipped with BLDC drive circuit and control program.

Application Scenarios: Equipment with customer’s own mature main‑control solution, drive‑integrated mainboard, pursuit of ultra‑compact size, and purely constant‑speed operation.

2、Built‑in Driver Board Solution (Basic Speed‑adjustment Type)

The motor integrates a miniature built‑in driver board with five outgoing wires, implementing basic BLDC drive logic.

Features: Supports PWM speed adjustment, forward/reverse switching, start‑stop control and over‑current stall protection. The motor can be controlled by signals without complex mainboard programming. Built‑in basic voltage stabilization and anti‑burn protection ensure high stability.

Application Scenarios: Most intelligent devices, small home appliances and small transmission mechanisms requiring speed regulation and direction reversal. It is currently the mainstream version for customized deliveries.

3、Hall‑Sensor Board Solution (Precision Intelligent Control Type)

Equipped with complete Hall‑sensor board, 8‑wire definition including phase wires and Hall signal wires for full‑range signal feedback.

Features: Real‑time feedback of motor speed and rotor position, supporting closed‑loop control, stable constant‑speed rotation and jitter‑free low‑speed operation. Suitable for working conditions requiring precise speed regulation, constant torque output and high‑frequency start‑stop, delivering the highest intelligence level.

Application Scenarios: High‑end precision equipment, intelligent gimbals, automatic fine‑tuning mechanisms and smart power modules requiring closed‑loop feedback.

IV. High‑Precision Expansion Customization Description for Encoder

For high‑end equipment requiring ultra‑high‑precision positioning, angle calibration and accurate speed acquisition, encoders can be added to all outer‑diameter BLDC planetary geared motors to realize micron‑level dynamic monitoring and closed‑loop positioning control.

Important Note: The encoder is a precision expansion accessory. It involves non‑standard structures including body stacking, wire outlet position, installation space and code disc matching, and cannot use general standard molds. If customers require encoder installation, drawings of equipment structure, installation limit dimensions, wire outlet mode and precision parameter requirements must be provided. We will perform exclusive structural customization, code‑disc matching and program adaptation based on drawings to guarantee positioning accuracy and assembly fitness.