EP-AF 시리즈 고강성 출력축 인라인 유성 기어박스 (EP-AF042~EP-AF220 및 EP-AFX 변형)
The EP-AF Series is a square-flange inline planetary gearbox with an enlarged diameter, high-rigidity output shaft designed for applications where a gear, pulley, sprocket, or cam is mounted directly on the shaft end — imposing radial and bending loads that a standard-diameter output shaft is not optimised to carry. Eleven frame sizes span EP-AF042 to EP-AF220, covering 14 N·m to 2,000 N·m output torque. Three backlash grades — P0 (≤1 arcmin), P1 (≤3 arcmin), and P2 (≤5 arcmin) single-stage — serve applications from precision servo axes to general automation. Single-stage efficiency reaches ≥97%, operating temperature −10 °C to +90 °C, and IP65 is standard. The EP-AFX variant covers the same specification up to 1,200 N·m in ten frame sizes. Both are the directly catalogued ‘Hi radial load’ series in the Korea Ever-Power inline precision planetary gearbox range.
EP-AF Series — High-Rigidity Enlarged Output Shaft Inline Planetary Gearbox

Load
EP-AF is the Korea Ever-Power inline precision planetary gearbox series catalogued specifically for high radial load applications. The enlarged diameter output shaft directly supports gear, pulley, sprocket, and cam mounting without a separate bearing housing — a configuration the standard-diameter EP-AB shaft is not rated for.
그만큼 EP-AF series high-rigidity inline planetary gearbox differs from the EP-AB square-flange series in exactly one structural dimension: the output shaft diameter. EP-AF uses an enlarged diameter output shaft whose increased cross-section delivers substantially higher bending stiffness and radial load capacity — the property that defines an EP-AF application. When a belt pulley, timing gear, or eccentric cam is mounted directly on the output shaft end and its weight or belt tension creates a radial force on the shaft, the EP-AF's enlarged shaft resists the resulting bending moment without deflection that would compromise tooth mesh accuracy, bearing life, or positioning repeatability.
All other specifications — backlash grades P0/P1/P2, single-stage efficiency ≥97%, operating temperature −10 °C to +90 °C, IP65 protection, and the complete ratio set from i=3 to i=100 two-stage — are identical to EP-AB. The EP-AFX variant covers the same specification at a reduced maximum torque of 1,200 N·m in ten frame sizes, for applications where the full 2,000 N·m of EP-AF220 is not required.
The High-Rigidity Output Shaft — Why Output Shaft Diameter Is the Critical Selection Variable
STANDARD SHAFT — EP-AB
│
│ Standard shaft Ø
│ ↓
[Load via coupling]
No radial force on shaft
HIGH-RIGIDITY SHAFT — EP-AF
│ ↑
│ Enlarged shaft Ø
│ ← Radial force F
│ Bending stiffness
│ ∝ Ø⁴ (4th power)
Three Load Cases Where the Enlarged Shaft Makes the Critical Difference
① Belt and Timing Belt Drives — Tension Creates Radial Force
A synchronous timing belt pulley or V-belt pulley mounted directly on the EP-AF output shaft creates a radial force equal to the vector sum of the tight-side and slack-side belt tensions. At 100 N·m output torque with a 50 mm radius pulley, tight-side tension alone reaches approximately 2,000 N. This radial force bends the output shaft. The enlarged shaft of EP-AF — with bending stiffness scaling with the fourth power of diameter — resists this bending with significantly lower deflection than a standard-diameter shaft of the same length, maintaining pulley alignment and protecting the gearbox output bearing from premature fatigue.
② Spur and Helical Gear Direct Mounting — Mesh Force at Shaft End
When a spur or helical gear is mounted on the EP-AF output shaft end as part of an open gear pair — common in Korean packaging machines, printing presses, and automatic transport systems — the gear mesh transmits both tangential force (the torque-producing component) and radial separating force (from the pressure angle, typically 20° for spur gears). For a 20° pressure angle gear, the radial force is approximately 36% of the tangential force. The EP-AF enlarged shaft handles the combined bending and torsion loading without deflection that would alter the gear mesh centre distance and generate noise or premature tooth wear.
③ Eccentric Cam and Offset Loads — Gravity and Dynamic Bending
Eccentric cam drives, offset tooling heads, and cantilevered circular fixtures mounted on the output shaft end create both a static gravitational bending load (the weight of the cantilevered mass times its moment arm from the bearing) and a dynamic bending load as the mass rotates and the centrifugal force direction changes. The EP-AF enlarged shaft withstands the peak combined load — static plus dynamic — without shaft deflection at the cam profile that would introduce cam-follower tracking error and positioning deviation in the machine cycle.
EP-AF vs EP-AB — The Output Shaft Load Decision
| Load Condition at Output Shaft | → Choose EP-AF ★ | → Choose EP-AB |
|---|---|---|
| Load connection method | Direct shaft-end mounting — gear, pulley, sprocket, cam | Coupling or flange connection to load |
| Radial force on output shaft | Present — belt tension, gear mesh force, offset mass | Minimal — coupling handles misalignment, load is axial |
| Separate output bearing housing | Not needed — enlarged shaft carries radial load directly | May be needed if radial load is high |
| Machine design intent | Compact: gearbox output shaft IS the driven shaft | Two-shaft arrangement with coupling between them |
| Precision / Efficiency / IP | Identical: P0/P1/P2 · ≥97% single-stage · −10 to +90 °C · IP65 | |
| Gear ratios available | Identical: single i=3–10, two-stage i=12–100 (17 values) | |
If your load connects to the gearbox output shaft via a flexible coupling or through a rotary table flange where the shaft transmits only torque, specify EP-AB. If the load is mounted directly on the output shaft end and the shaft must also carry radial force and bending moment, specify EP-AF. The difference is not about precision grade — it is about shaft structural capacity.
EP-AF and EP-AFX — Complete Specifications
EP-AF Series — Full Torque Range
| EP-AF Specifications | |
| Torque (T2N) | 14 – 2,000 N·m |
| Frame sizes | AF042/060/060A/075 075A/100/100A/140 140A/180/220 |
| Output shaft | Enlarged diameter — high rigidity |
| 출력 플랜지 | Square (same as EP-AB) |
| P0 backlash | Single ≤1' · Two-stage ≤3' |
| P1 backlash | Single ≤3' · Two-stage ≤5' |
| P2 backlash | Single ≤5' · Two-stage ≤7' |
| 단일 단계 비율 | 3/4/5/6/7/8/9/10 |
| Two-stage ratios | 12/15/16/20/25/28/ 30/32/35/40/45/50/ 60/70/80/90/100 |
| 능률 | ≥97% (1-stage) · ≥94% (2-stage) |
| Temperature | −10 °C to +90 °C |
| IP rating | IP65 standard |
EP-AFX Series — Reduced Torque Variant
| EP-AFX Specifications | |
| Torque (T2N) | 14 – 1,200 N·m |
| Frame sizes | AFX042/060/060A/075 075A/100/100A/140 140A/180 (no AFX220) |
| Output shaft | Same enlarged diameter as EP-AF |
| Backlash grades | P0/P1/P2 — identical to EP-AF |
| Gear ratios | Identical to EP-AF |
| Efficiency / Temp / IP | Identical to EP-AF |
| When to choose AFX | Output torque ≤1,200 N·m and AF220 frame is oversized for the machine design — AFX180 is the largest frame |
| When to choose AF | Output torque 1,200–2,000 N·m requires AF220; or AF is already specified and AFX offers no installation advantage |
Note: EP-AF and EP-AFX are not interchangeable at all frame sizes — AFX does not include the 220 mm frame. At frames 042–180, both carry the same enlarged shaft geometry and are dimensionally compatible.
EP-AF frame numbers (042, 060, 075, 100, 140, 180, 220) differ from EP-AB frame numbers (042, 060, 090, 115, 142, 180, 220). At the same body size level — e.g. "medium frame" — EP-AF075 is not the same dimensions as EP-AB090. Do not assume interchangeability between AF and AB frame numbers. Always compare dimensional drawings when specifying a replacement or alternative between these two series.
Model Designation Guide — EP-AF and EP-AFX Part Numbers
High-Rigidity Shaft
Square Flange Inline
100 mm
(AF scale, ≠ AB115)
(two-stage)
S1: smooth
S2: with keyway
P0 ≤1' / P1 ≤3'
P2 ≤5' (single-stage)
Applications — Direct Shaft-End Load Mounting in Korean Industry
Packaging Machines — Belt Drive Axes with High Tension
Korean flexible packaging machine OEMs building VFFS and HFFS machines use EP-AF for axes where a timing belt pulley is mounted directly on the gearbox output shaft — the cross-seal jaw drive, film feed roll drive, and registration correction axis. Timing belt tension at 50–150 N·m output torque generates 1,000–3,000 N of radial force on the output shaft; the EP-AF enlarged shaft carries this load without deflection that would change the belt mesh pitch line distance and degrade registration accuracy. EP-AF075 and EP-AF100 at P1, ratios 5:1–25:1 cover the majority of Korean VFFS cross-seal axis requirements.
Printing Machines — Open Gear Register Drives
Korean commercial and industrial printing machine register axes use open spur gear pairs where the EP-AF output shaft carries the driven gear directly — the gear mesh radial separating force adds to the torque loading on the shaft. Register axis accuracy requires that the gear centre distance remains constant through the print cycle; this demands a rigid output shaft that does not deflect under mesh loads. EP-AF100 P0 at i=10 to i=32 covers the speed reduction range of Korean offset and flexographic register correction drives.
Textile Machinery — High-Speed Shaft-Mounted Drives
Korean textile machine warp beam drives, take-up roll drives, and yarn tension control axes mount large-diameter winding spools directly on the gearbox output shaft — the spool weight and winding tension both create radial force. At elevated speeds and large-diameter loads, the dynamic radial force from the rotating mass can exceed the static load. EP-AF140 P1 at two-stage ratios 20:1–50:1 covers the torque requirements of Korean industrial textile winding and take-up machinery.
Application by Load Type
- Belt drives
Timing belt, V-belt tension radial load on shaft
- Open gear pairs
Mesh separating force — packaging, printing
- Cam drives
Eccentric cam, offset tooling — bending moment
- Sprocket drives
Chain tension — conveyor and transport systems
- Winding spools
Spool weight + winding tension — textile, cable
- Cantilevered tooling
Offset tool heads — machine tool rotary stations
CNC Machine Tool Cam Stations
Korean CNC multi-spindle turning centres and cam-driven transfer machines use EP-AF for the cam shaft drive — the cam profile imparts cyclic radial forces on the output shaft as the follower tracks the profile. The EP-AF enlarged shaft resists the peak follower force without shaft deflection that would alter the cam motion law and introduce timing errors in the machining cycle.
Conveyor and Transport Chain Drives
Korean automated logistics and assembly conveyor systems mounting a sprocket directly on the EP-AF output shaft experience chain tension as a radial force — particularly on return-path rollers where the tight-side tension acts directly on the shaft end. EP-AF100 P2 at ratios 10:1–40:1 covers the majority of Korean conveyor chain drive speed-reduction requirements, eliminating the need for a separate sprocket shaft and bearing housing.
Agricultural Machinery Drives
Korean precision agriculture equipment — fertiliser spreader disc drives, seeder roller drives — mounts the spreading disc or seeder roller directly on the EP-AF output shaft. The disc or roller weight plus the reaction force from distributing material creates a combined radial and axial load that the high-rigidity shaft absorbs, maintaining disc position geometry and distribution uniformity across the full working width.
Quality Certifications & Testing Standards
- ✔Output shaft diameter and runout verified — enlarged shaft geometry confirmed against drawing
- ✔Backlash grade (P0/P1/P2) certified per unit on shipping documentation
- ✔Full-load efficiency test at rated output torque per production batch
- ✔IP65 ingress test per IEC 60529 — every unit
- ✔Material certificate and dimensional report with each delivery

Why Korean Engineers Specify Korea Ever-Power EP-AF Series
⚡
The Only Korea Ever-Power Inline Series Rated for Hi Radial Load
Among the Korea Ever-Power inline precision planetary gearbox families, EP-AF and EP-AFX are the series specifically catalogued for high radial load operation. The "Hi radial load (AF)" designation in the product range means EP-AF is the product of choice when the output shaft must carry radial force — not a workaround or a field modification of EP-AB.
🏗️
Eliminates Separate Bearing Housing and Output Shaft Assembly
In a standard-shaft gearbox design with direct belt or gear mounting, machine designers often add a separate bearing housing and shaft at the output side to carry the radial load and protect the gearbox output bearing. EP-AF's enlarged shaft eliminates this additional assembly — reducing the machine's part count, axial length, and assembly time while maintaining the required radial load capacity through the gearbox output shaft itself.
🎯
Same Precision Grades as EP-AB — P0/P1/P2 on All Ratios
Specifying EP-AF for a belt-driven servo axis does not require compromising on backlash precision. P0 (≤1 arcmin), P1 (≤3 arcmin), and P2 (≤5 arcmin) are available on all ratios and all frame sizes — the same precision specification as EP-AB. Korean packaging and printing machine builders can specify EP-AF at P1 for closed-loop register control with direct belt drive, without a separate precision gearbox for the register axis.
📐
Complete 3–100 Ratio Range — No Gap
EP-AF covers the full single-stage range of 3 through 10 and the two-stage range from 12 to 100 — the same complete ratio set as EP-AB. Korean machine builders who standardise on EP-AF for radial-load axes do not need to source a separate product for any required gear ratio within this range.
⚙️
AF + AFX Two-Size Strategy for Procurement Efficiency
Korean OEMs building machine families with varying power levels can use EP-AFX for lower-torque variants (up to 1,200 N·m) and EP-AF for higher-torque or largest-frame variants (up to 2,000 N·m, AF220 only). Both share identical shaft geometry, gear ratios, and backlash grades — simplifying the machine architecture design and reducing the number of distinct gearbox specifications in the BOM.
🇰🇷
Korean Radial Load Calculation Support
Korea Ever-Power's Korean application team calculates the actual radial force at the output shaft for your belt drive, gear drive, or cam application — confirming that the EP-AF frame and ratio you have selected is within the rated radial load capacity of the enlarged shaft at your operating speed. This review is provided in Korean and is part of the standard pre-order technical support.

고객 리뷰 및 애플리케이션 피드백
5 ★
87%
4 ★
11%
≤3 ★
2%
EP-AF100 P1, i=20 for the cross-seal jaw drive on our VFFS machine — direct timing belt pulley, 90 mm radius, running at 120 seals/min. Previously we had a standard-shaft precision gearbox on this axis with a separate outboard bearing to carry the belt tension. The EP-AF eliminated the outboard bearing, shortened the jaw drive assembly by 85 mm, and removed one additional bearing from the PM schedule. At 18 months and 6 machines, no output bearing failures and no belt alignment deviations. The Korea Ever-Power team confirmed the belt tension radial force calculation before we finalised the specification — that was the deciding factor in our supplier choice.
EP-AF075 P0, i=25 for the register correction axis on an offset printing press — direct spur gear mounting. We had been using an EP-AB at the same frame with a flexible coupling between the gearbox and the gear shaft; we were getting backlash-induced register variation at high speed reversals. Switching to EP-AF with direct gear mounting eliminated the coupling compliance. The P0 grade (≤1 arcmin) held the register within our ±0.05 mm specification consistently across a 12-hour production run. Output shaft runout confirmed at 0.004 mm by our incoming inspection. 23 months, 4 machines, zero register deviation incidents.
EP-AF140 P1, i=35 for a warp beam drive on an industrial weaving machine — 450 mm diameter warp beam mounted directly on the output shaft, running at 41 rpm from a 1,450 rpm motor. The beam weight (68 kg) and winding tension create a substantial radial moment on the output shaft. Previous standard-shaft gearboxes on this application required replacement at intervals of 8–14 months due to output bearing fatigue. EP-AF has now run 27 months on 8 machines without a single output bearing replacement. The enlarged shaft clearly makes the difference in this application — we should have specified it from the start.
Share your EP-AF application experience. Contact Korea Ever-Power: [email protected]
Accessories & Complementary Transmission Products
EP-AF is the inline series for direct shaft-end load mounting. When the radial load capacity of the enlarged shaft is not required — when the output load connects via a coupling — the EP-AB square-flange precision planetary gearbox is the standard-shaft alternative with identical precision grades and ratio coverage. Korea Ever-Power supplies the drive system accessories that integrate directly with EP-AF output shafts in Korean machine designs.

CV Joint Drive Shafts
For EP-AF configurations where the output shaft drives a load at an angular or parallel offset — belt drive systems where the driven shaft is not coaxial with the EP-AF output, or dual-drive configurations on large rotary tables — precision CV joint drive shafts transmit the output torque through the offset without additional radial loading on the EP-AF shaft end, complementing the high-rigidity shaft design.
Worm Gear Reducers
For vertical EP-AF output axes with direct-mounted belt pulleys or chain sprockets — hoist and lift mechanisms where the load must be held on power-off — a downstream self-locking worm gear reducer provides gravity load holding at any position. Worm reducers also extend the EP-AF total ratio range beyond the two-stage maximum i=100 for very low speed applications.
Agricultural Gearboxes
For Korean precision agriculture applications where EP-AF drives a fertiliser spreader disc, seeder roller, or sprayer pump directly — the enlarged shaft carries the disc or roller weight as a radial load — downstream bevel and spiral-bevel agricultural gearboxes from Korea Ever-Power provide multi-output PTO configurations, extending the EP-AF drive train to distribute power across multiple working heads in a single agricultural machine pass.
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