EP-BAF Series High-Precision Planetary Gearbox — High-Rigidity Output Shaft (EP-BAF042 to EP-BAF220)

그만큼 EP-BAF series high-precision planetary gearbox addresses a specific structural problem that the standard EP-BAB series is not designed for: applications where a gear, timing pulley, sprocket, cam, or eccentric is mounted directly onto the output shaft end, imposing a concentrated radial force and bending moment on the shaft itself — not on the flange face. This high-precision planetary gearbox achieves this through an output shaft with a larger diameter than the equivalent EP-BAB frame, increasing the shaft's second moment of area and its resistance to bending deflection under combined torsional and radial loading.

Seven frame sizes from EP-BAF042 through EP-BAF220 cover rated output torque up to 2,000 N·m. The same P1 backlash of ≤3 arcmin single-stage and ≥95% single-stage efficiency as the EP-BAB series are maintained — the high-rigidity shaft design adds radial load capacity without sacrificing the precision or efficiency that define Korea Ever-Power's standard precision family. Published moment of inertia data supports servo inertia-ratio verification at the design stage.

The Shaft Loading Problem Standard Gearboxes Don't Solve

In a standard servo gear reducer installation, the output shaft connects to the load via a coupling or a flange-mounted rotary table — and the shaft itself carries only torsion. Radial forces from the load are supported by separate bearings in the machine structure. In this configuration, EP-BAB's standard shaft diameter is adequate.

The problem arises when a gear, timing pulley, or sprocket is mounted directly on the gearbox output shaft without a separate bearing support between the gear and the gearbox housing. In this case, the mesh force from the driven gear — which is purely radial — acts as a cantilever bending load on the output shaft at the distance from the gearbox face to the gear mesh point. This bending load causes shaft deflection and, at the gearbox output bearing, generates a reaction radial force that the output bearing must sustain on top of its normal operating load.

EP-BAF's larger-diameter output shaft responds to exactly this scenario. The shaft bending stiffness (EI) scales with the fourth power of shaft diameter — a modest increase in shaft diameter produces a disproportionate increase in radial load capacity and a corresponding reduction in shaft deflection. The output bearing reaction force is reduced, bearing L10 life is extended, and the radial shaft deflection that would otherwise manifest as gear mesh quality degradation or positioning drift is suppressed.

Press Feed Roll Drives

Progressive stamping press feed systems drive the material feed roll pair through a direct gear mesh from the gearbox output shaft. The normal force between the meshing gears at high-speed stamping rates (up to 200 strokes/min) combined with the directional reversal between feed and return stroke creates pulsating radial shaft loads. EP-BAF090 and EP-BAF142 at 10:1–25:1 cover the torque and radial load requirements of precision press feed gear trains.

Screen Printing Machine Drive Axes

Precision screen printing machines — for electronics, textile, and solar cell printing — use servo drives to control squeegee pressure and stroke speed through cam-actuated mechanisms. The cam follower load and the belt or gear drive from the output shaft impose combined radial and torsional loads. EP-BAF's P1 precision ensures repeatable positioning across the squeegee stroke cycle, while the reinforced shaft handles the combined loading at high cycle rates.

Shuttle Conveyor Transfer Axes

Shuttle conveyor transfer mechanisms use timing belt drives from the servo gearbox output shaft to synchronise part transfer across multiple stations. Belt pre-tension adds a sustained radial load to the shaft in addition to the acceleration and deceleration torque during shuttle moves. For high-frequency short-stroke shuttle systems, EP-BAF's shaft radial load rating sustains the combined belt tension and dynamic load without premature bearing failure.

• ✔Backlash measured per unit — P1/P2 grade certified
• ✔Output shaft radial runout measured — confirming bearing-to-shaft fit quality
• ✔Full-load torque test at 110% rated output torque
• ✔Noise check at 3,000 rpm — <65 dB(A) confirmed per unit
• ✔Material cert, inertia value, and dimensional report shipped with every unit

Output shaft radial runout verified per unit — confirming high-rigidity shaft dimensional integrity

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EP-BAF090 at 10:1 for a progressive stamping press feed system driving the material advance rolls through a direct spur gear mesh. We had two bearing failures on EP-BAB090 in 8 months — the gear mesh radial force was within the torsional rating but above the shaft radial load limit (which we hadn't checked). Switched to EP-BAF090: 19 months now at 180 strokes/min, no bearing issues. The inertia data confirmed our 1,500W servo was correctly sized without needing to build a prototype first.

EP-BAF090 at 25:1 for a timing belt shuttle conveyor drive — 65 N belt pre-tension on a 40T timing pulley mounted directly on the output shaft. Previous standard-flange precision gear reducer showed increasing shaft runout after 6 months from belt tension. EP-BAF090 has maintained shaft runout within spec for 14 months of continuous three-shift production. P1 precision eliminates the belt-skip registration errors we were getting from the previous unit's backlash drift. Korea Ever-Power's Korean-language shaft load calculation helped us confirm the selection in one day.

EP-BAF142 at 35:1 for a rotary cam drive on an automated electronic component assembly machine — 48 stations, cam follower load peaks at 850 N radial, cycling at 120 parts/min. Previous standard precision gearbox failed at 4 months from shaft fatigue in the bearing seat area. EP-BAF142's enlarged shaft has now run 21 months at the same cycle rate without any maintenance intervention. The P1 backlash on the cam drive index has held within 0.02° measured at the station platen — our tightest tolerance application. Excellent Korea Ever-Power support throughout the design phase.

EP-BAF060 at 50:1 two-stage for a solar cell screen printing squeegee cam drive. Important note for others: EP-BAF060 single-stage torque at i=5 is 22 N·m — significantly lower than EP-BAB060. We chose the 50:1 two-stage configuration which gives full-spec 60 N·m, and it has worked perfectly for 16 months. If you need single-stage at low ratios on the 060 frame, confirm the torque rating with Korea Ever-Power first. The high-rigidity shaft handles our cam follower radial load without any issue. Korea Ever-Power was upfront about the small-frame torque reduction during our selection call.

큐What exactly is "shaft radial load capacity" for a planetary gearbox and how do I calculate whether my application exceeds it?

Shaft radial load capacity is the maximum force perpendicular to the output shaft axis that the output shaft and its supporting bearings can sustain continuously without exceeding bearing fatigue life or shaft bending stress limits. To calculate: (1) For a gear drive — determine the tangential force (F_t = 2T/d, where T is torque and d is pitch diameter of the gear) and the normal force (F_n = F_t / cos(pressure angle)); F_n is the shaft radial load. (2) For a belt drive — use belt pre-tension plus half the transmitted torsional force as the radial load. (3) For a cam — calculate the cam follower contact force from the cam profile geometry and the follower spring preload. Compare your calculated radial load to the rated shaft radial load for your selected EP-BAF frame and shaft extension point. Contact Korea Ever-Power with your specific loading data for a verified selection.

큐Why does EP-BAF042 have lower rated torque than EP-BAB042 at the same ratio?

The enlarged output shaft diameter of EP-BAF requires a larger shaft bore through the planet carrier centre. At the 042 mm body size, this larger bore reduces the material cross-section available for the planet carrier arms and the planet bearing seats — a geometry constraint that slightly reduces the planet carrier's torque transmission capacity at the smallest frame size. At EP-BAF090 and above, the body size is large enough that the shaft diameter increase has negligible effect on the planet carrier geometry, so rated torque is essentially the same as the equivalent EP-BAB frame. This is an honest constraint of the high-rigidity shaft design at small body sizes, not a quality issue.

큐Can I use EP-BAF where EP-BAB is specified, as a direct substitute?

For EP-BAF090 and above, yes — the output flange dimensions and gear ratios are compatible, backlash and efficiency are the same, and the torque ratings are essentially equivalent. The only change is the larger output shaft diameter, which requires the mating coupling, gear bore, or belt pulley bore to match the new shaft diameter. For EP-BAF042 and EP-BAF060, check the rated torque at your specific ratio before substituting — the single-stage torque at low ratios may be lower than the EP-BAB unit you are replacing.

큐What is the difference between EP-BAF (high-rigidity shaft) and EP-BAE (large flange)? Both claim to handle heavy loads.

They solve different structural problems. EP-BAE (large flange) handles overturning moments at the flange face — forces perpendicular to the shaft that try to tip the gearbox body away from the mounting face, stressing the mounting bolts. EP-BAF (high-rigidity shaft) handles radial forces on the output shaft itself — the gear mesh force or belt tension that acts on the shaft at some distance from the gearbox housing. If your load is a heavy rotary table workpiece acting on the flange, choose EP-BAE. If your load is a gear, pulley, or cam mounted on the shaft end, choose EP-BAF. If your application has both conditions simultaneously, contact Korea Ever-Power — a combined solution may be available.

큐Does mounting a spur gear directly on the EP-BAF output shaft require any additional consideration for backlash specification?

Yes. The gearbox P1 ≤3 arcmin backlash is measured at the output shaft — the gear teeth mounted on that shaft add their own backlash (tooth-to-tooth clearance with the mating gear). Total system backlash at the load is the sum of the gearbox backlash and the gear pair backlash. If your application has a tight total backlash requirement, specify P1 for the EP-BAF to minimise the gearbox contribution, and use precision-ground gears with tight tooth clearance tolerances for the mounted gear pair. Korea Ever-Power can assist with calculating total system backlash budget from gearbox, gear pair, shaft deflection, and thermal expansion contributions.