Internal Planetary Gear Kit – M3-M12, DIN6-9, Multi-Mat.

The internal planetary gear kit — also called a planetary gear set — is a complete, precision-matched assembly of all three functional members of the planetary gear mechanism: the sun gear, the planet gears (mounted on a planet carrier), and the ring gear. The kit ships as a matched set, with all gear elements cut to the same module and pressure angle, checked for correct backlash and tooth contact as an assembly, and ready for direct installation into the customer's housing. Supplying matched planetary gear kits eliminates the risk of mixing incompatible gears from different production batches and ensures that the assembled planetary stage achieves the specified transmission ratio and accuracy grade.

Korea Ever-Power's internal planetary gear kits possess numerous advantages over parallel-axis gear trains in terms of power density, tolerance insensitivity, noise characteristics, and kinematic flexibility. Manufactured in modules M3–M12 with all standard and non-standard specifications available per customer drawing. Factory with large inventory of tools, raw materials, and semi-finished products for fast delivery. Export qualifications held. Shipping by sea, air, and parcel.

① Coaxial Layout — No Countershafts

The sun gear, planet carrier, and ring gear are all concentric — they all rotate about the same central axis. This eliminates the countershafts and intermediate gears required by conventional parallel-axis transmissions. The result is a shorter, lighter drivetrain with fewer components, lower assembly cost, and simpler housings. The input shaft and output shaft are on the same axis, enabling compact inline drive arrangements that are mechanically impossible with offset gear trains.

② Always-Meshed Gears — Long Life

All gears in a planetary kit are always in mesh — no gear sliding is required when changing gear ratio (as in a manual gearbox). Because the gears never need to slide into engagement, the tooth tip impact and friction that causes wear in sliding-mesh transmissions is eliminated. Friction and wear are significantly reduced, and the service life of the kit is extended accordingly. This is a key structural advantage over conventional change-speed gearboxes.

③ Power Split — Compact and Strong

The planetary gear kit's load is distributed across multiple planet gears simultaneously — typically 3 or 4. Each planet gear carries only a fraction of the total transmitted torque. This power-split principle allows each individual gear tooth to be much smaller (lower module, narrower face width) than an equivalent single-mesh gear train at the same torque capacity, producing a simple, compact structure with high load capacity relative to its size and weight.

④ Multiple Transmission Ratios

By selectively fixing, driving, or freeing any of the three members (sun gear, planet carrier, ring gear) through clutches and brakes, a single planetary kit can produce multiple transmission ratios and reverse — the operational principle behind the automatic transmission. Combining two or three planetary kits in a compound arrangement allows a modern automatic transmission to produce 6, 8, or 10 distinct forward ratios plus reverse from a compact, lightweight assembly.

Automotive Automatic Transmissions

Planetary gear kits are the fundamental building block of every automatic transmission — two or three rows of planetary kits combined with clutches and brakes produce all forward ratios and reverse. The always-meshed design and coaxial layout make the planetary kit indispensable for smooth, compact automatic gearboxes in passenger cars, trucks, and hybrids.

Electric Vehicle Drivetrains

Planetary gear kits in EV motor single-speed and two-speed reducer stages. The compact coaxial layout allows the electric motor, planetary reducer, and differential to be integrated into a single drive unit — the e-axle. Matched planetary kits with ground gears and tight backlash are specified for EV drives to minimise transmission error and gear rattle under regenerative braking torque reversals.

Industrial Robots and Cobots

Precision planetary gear kits DIN 6–7 in servo actuator planetary gearboxes for industrial robot joint drives and collaborative robot arm joints. Matched kits from Korea Ever-Power ensure that the sun gear, planet gears, and ring gear all share the same module, pressure angle, and accuracy grade — minimising kinematic error and maximising the position servo bandwidth at the robot joint output.

Industrial Planetary Gearboxes

Planetary gear kits M5–M12 in inline planetary gearbox reducers for conveyor drives, agitator drives, extruder drives, and fan drives. The power-split across 3–4 planet gears allows a compact planetary reducer to handle continuous-duty industrial loads that would require a much larger parallel-shaft gearbox at equivalent torque and ratio.

Aircraft and High-Speed Rail

Matched planetary gear kits in aircraft actuator planetary stages, APU starter gearboxes, and high-speed rail traction planetary reducers. The high power density and kinematic flexibility of the planetary kit are essential for weight-critical aviation applications — and the always-meshed structure eliminates the engagement shock that would damage high-speed aerospace gear trains.

Medical and Semiconductor Equipment

Stainless steel or aluminium planetary gear kits M3–M5 DIN 6 in surgical robot joints, imaging table positioning actuators, wafer handling robot planetary drives, and semiconductor equipment micro-actuators. Matched-kit supply ensures that all elements of the planetary assembly meet the same material and accuracy specification — critical for the traceability requirements of medical device and semiconductor equipment approval processes.

Does Korea Ever-Power have export qualifications?

Yes — Korea Ever-Power holds full export qualifications. Planetary gear kits are shipped internationally by sea freight, air transportation, and parcel courier depending on the quantity, urgency, and destination. For urgent small-quantity kit orders, express courier (DHL, FedEx, UPS) provides 3–7 day delivery to most destinations. For large production batches, sea freight is the most economical option.

What is the minimum order quantity for a planetary gear kit?

The minimum order quantity depends on the specific planetary gear kit ordered — module, number of planets, material, and accuracy grade all affect the production setup and therefore the minimum run size. Send the drawing or specification and Korea Ever-Power will confirm the minimum quantity for that kit configuration. For sample kits (for engineering evaluation and assembly fit confirmation), samples are accepted with the sample fee and freight paid by the customer, refunded on subsequent bulk order placement.

Where is the factory located?

Korea Ever-Power's factory is located in Hangzhou City, Zhejiang Province, China. The facility is a precision gear manufacturing plant — not a trading company — with all planetary gear kit components manufactured in-house, including gear cutting, heat treatment, surface finishing, and assembly. Factory visits are welcome by appointment. Contact Korea Ever-Power to arrange the visit schedule and to confirm current production status for your planetary gear kit specification.

How does Korea Ever-Power achieve fast delivery without stock?

Korea Ever-Power maintains a large inventory of tools (gear shaping cutters, broaches, grinding wheels), raw material blanks, and semi-finished planetary gear kit components for standard module sizes (M3, M4, M5, M8, M12). When an order is placed, the pre-cut blanks bypass the longest lead-time operations (forging, rough turning) and proceed directly to gear cutting, heat treatment, and finishing — reducing the total production time significantly compared with a start-from-raw-material process. For custom kits, the standard 20/25 business day lead time applies from drawing confirmation.

Can Korea Ever-Power manufacture planetary gear kits not listed on the website?

Yes — Korea Ever-Power provides full custom planetary gear kit manufacturing with excellent delivery options equivalent to standard kits. Any module, tooth count, number of planets, carrier geometry, bore diameter, material, or surface treatment can be specified. Send the drawing or specification and we will confirm feasibility, lead time, and price. Contact our team to begin.

"We build compact inline planetary gearboxes for conveyor system drives and source matched planetary gear kits M5 in C45 steel DIN 7 from Korea Ever-Power. Supplying the kit as a matched assembly — sun gear, three planet gears, carrier, and ring gear in one order — eliminates the risk of module mismatch between separately sourced components. Backlash at our assembly check was within our 0.05 mm spec across all six kit samples. Delivery 23 business days."

Kim Seong-jun  |  Industrial Gearbox Design Engineer, Incheon Drive Systems Co.  ·  Q1 2026

"We manufacture EV motor reducer e-axles and use Korea Ever-Power's planetary gear kits M4 alloy steel DIN 6, tooth-ground. The matched-kit supply means all gears in each assembly share the same heat treatment batch and accuracy confirmation — critical for our NVH target of below 62 dB(A) at the mesh frequency. Korea Ever-Power's factory in Hangzhou confirmed the coaxiality of sun, planet, and ring axes during kit assembly inspection."

Lee Jae-hyeon  |  EV Drivetrain Engineer, Gyeonggi Electric Mobility Co.  ·  Q4 2025

"We distribute planetary gear kits across the Korean industrial market. Korea Ever-Power's large inventory of semi-finished M5 and M8 blanks means standard kit orders routinely complete faster than the 25-day bulk lead time — our average actual delivery was 21 days across 12 orders last year. Sea freight from Hangzhou to Busan: 4 days. No non-conformances in the matched-kit assemblies since we began sourcing from Korea Ever-Power."

Park Hyeong-il  |  Precision Gear Distribution Manager, Busan Industrial Components Co.  ·  Q2 2026

"We needed a custom planetary gear kit — non-standard 4-planet arrangement, module 3.5, stainless steel, for a medical rehabilitation robot joint. Korea Ever-Power confirmed feasibility, produced a drawing for approval, and delivered sample kits in 22 business days. Kit coaxiality confirmed on our CMM. Stainless material certificate and accuracy report included. The custom kit lead time was comparable to the standard kit lead time — significant for our development programme schedule."

Choi Min-jae  |  Rehabilitation Robot Joint Engineer, Daejeon Medical Robotics Co.  ·  Q3 2025