BAE Series High-Precision Planetary Gearbox — Large Flange Type (EP-BAE050 to EP-BAE235)

The EP-BAE series high-precision planetary gearbox is Korea Ever-Power's large-flange variant, designed for applications where the gearbox-to-machine interface must carry significant overturning moments — bending loads applied perpendicular to the output shaft axis — in addition to the primary output torque. The defining engineering feature is an output flange outer diameter substantially larger than the gearbox body diameter, extending the bolt-circle radius and dramatically increasing the mounting interface's resistance to flange tipping, bending, and bolt-tension variation under dynamic load reversals.

Seven frame sizes from EP-BAE050 through EP-BAE235 cover rated output torque from 19 N·m to 2,000 N·m with P1 grade backlash of ≤3 arcmin single-stage and ≤5 arcmin two-stage, ≥95% single-stage efficiency, and noise below 65 dB(A). Korea Ever-Power publishes moment of inertia data for all seven EP-BAE frames — a key differentiator enabling servo drive engineers to perform inertia-ratio calculations before finalising motor and drive selection, without waiting for physical units.

Three Structural Problems the Large Flange Solves

Laser Cutting Rotary Chuck Drive

Rotary chuck drives for tube and profile laser cutting machines carry the workpiece chuck (mass 5–30 kg) cantilevered at the output shaft end. The EP-BAE large flange resists the overturning moment from this cantilevered mass under high-speed rotation without allowing the flange interface micro-rocking that would introduce radial runout at the chuck — directly affecting cut quality on round tube profiles.

CMM Rotary Table Integration

Coordinate measuring machine (CMM) rotary tables demand extremely low angular positioning uncertainty — any flange interface compliance appears as a measurement error at the workpiece surface. EP-BAE050 and EP-BAE070 at 25:1–50:1 provide the P1 ≤3 arcmin gear precision combined with the large-flange interface stiffness that CMM table applications require. The published inertia data allows CMM drive system engineers to verify servo tuning stability before system integration.

EV Battery Module Assembly

Heavy EV battery module assembly jigs — carrying module fixtures of 20–80 kg through multi-axis positioning — require servo drives that maintain dimensional accuracy under the overturning moments of asymmetric module weight distribution. EP-BAE120 and EP-BAE155 at 25:1–50:1 provide the combination of large-flange structural resistance and P1 precision that keeps module cell-to-cell alignment within tolerance across full assembly stroke.

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

Large flange face runout and output shaft concentricity — CMM verified per EP-BAE unit

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EP-BAE155 at 25:1 for a 4th axis heavy rotary table carrying 800 kg workpieces. We had tried EP-BAB142 first — the standard flange developed micro-fretting at the mounting face under the bending moment from the workpiece overhang after 3 months. Switched to EP-BAE155 with the large flange: the fretting stopped immediately and 22 months later the flange face is still within flatness spec at inspection. The inertia data let us confirm our 3.7 kW servo was adequate without a physical test — saved us 6 weeks on the development timeline.

EP-BAE090 at 50:1 for a 300 mm wafer handler theta axis. The large flange provided 8 more bolt positions compared to the standard-flange equivalent — critical for the handler's IPC-validated vibration specification in our fab's sub-10 nm process line. Published J data confirmed our servo inertia ratio at 4.2:1 — within our 5:1 spec limit — without needing a physical prototype. Wafer placement accuracy improved from ±0.08 mm to ±0.03 mm versus the previous standard-flange unit. 20 months operation, zero accuracy drift.

EP-BAE120 for the B-axis tilting head on a 5-axis machining centre used for aerospace aluminium parts. The spindle motor plus spindle assembly weighs 45 kg — the overturning moment at full ±90° tilt creates a significant bending load at the gearbox flange. Two competitors' standard-flange high-precision planetary gearboxes had shown angular positioning drift after 6 months at full tilt with cutting forces. EP-BAE120 with the large flange has now run 18 months at the same conditions with no measurable angular drift at the B-axis encoder. The flange runout certificate was part of our customer's acceptance documentation.

EP-BAE090 at 10:1 for a laser tube cutting rotary chuck drive — chuck plus chuck mechanism weighs 18 kg, cantilevered from the output shaft. At 3,000 rpm the overturning moment from the cantilevered chuck mass exceeded what our previous standard-flange precision gearbox could handle — we were seeing 0.12° radial runout at the chuck. EP-BAE090 large flange: runout dropped to 0.02°, cut-edge quality on 50 mm diameter stainless steel tube improved dramatically. 14 months, continuous 3-shift production, no maintenance intervention.

QWhat is an overturning moment and how does it affect gearbox flange selection?

An overturning moment (also called tipping moment) arises when a cantilevered load — a rotary table workpiece, a spindle head — applies a force perpendicular to the output shaft axis. This creates a bending couple at the flange interface: bolts on one side go into tension, bolts on the opposite side go into compression. The standard way to increase overturning moment capacity without changing the gearbox body size is to increase the flange outer diameter — which is exactly what the EP-BAE large-flange planetary gearbox does. The larger bolt-circle radius increases the moment arm of each bolt and distributes the load more evenly, preventing bolt-fatigue loosening and flange micro-movement that would appear as backlash drift at the workpiece.

QHow do I use the published inertia data for servo motor sizing?

Reflect all load inertias to the motor shaft: J_motor_side = (J_load + J_gearbox) ÷ i². Add J_motor_rotor to get total motor shaft inertia. Calculate inertia ratio = total motor shaft inertia ÷ J_motor_rotor. Industry guideline: ≤5:1 for standard servo, ≤10:1 with inertia compensation enabled in the drive. If the ratio exceeds your drive's specification, select a motor with higher rotor inertia or a larger gearbox frame to reduce J_load ÷ i² contribution. The published J data for EP-BAE (0.03 kg·cm² for BAE050 to 50.97 kg·cm² for BAE235) are the gearbox contributions; add the J values for the load hardware connected to the output shaft.

QThe EP-BAE frame number scale (050, 070, 090…) is different from EP-BAB (042, 060, 090…). Can I directly swap EP-BAE090 for EP-BAB090?

EP-BAE090 and EP-BAB090 have the same 90 mm body diameter and similar gear train specifications — output torque, backlash grade, and efficiency are comparable. The difference is the flange: EP-BAE090 has a larger output flange OD with a larger bolt-circle than EP-BAB090. This means the mounting hole pattern on the machine side must be updated when switching between the two series. Check the dimensional drawings of both frames before assuming a drop-in swap — the flange outer diameter and bolt-circle are different and will require different machine plate machining.

QIs the P1 ≤3 arcmin backlash verified under overturning moment load, or only under pure output torque?

Backlash is measured on a test bench applying a defined torque at the output shaft — this is standard industry measurement practice for precision planetary gearboxes and includes the contribution of the output shaft bearing and flange preload. For EP-BAE, the large flange design ensures that the flange interface contribution to total backlash is minimised under overturning moments — the main reason the large flange is chosen for applications where overturning moment is significant. Contact Korea Ever-Power if your application combines extreme overturning moment with P1 backlash requirements at operating temperature for a full application-specific verification.

QWhich Korean servo motor brands are compatible with EP-BAE input adapter plates?

Standard input adapter plates are available for Fanuc, Yaskawa, Mitsubishi, Siemens, LS Electric (APM/L7 series), Delta ECMA, and Hyundai HIGEN servo motor families — the brands most commonly used in Korean machine tool and semiconductor equipment production. For heavier frames (EP-BAE155 and above), specific servo motor models from Fanuc αi and Yaskawa SGMSV series are the most commonly paired. Contact Korea Ever-Power with your specific motor model number to confirm adapter plate availability and lead time.