EP-ZDWE Series Right-Angle Input Precision Planetary Gearbox

The EP-ZDWE series right-angle input precision planetary gearbox from Korea Ever-Power solves the most common spatial constraint in Korean servo drive design: the motor axis cannot be coaxial with the output shaft axis. In compact machine tool headstocks, robot wrist joints, narrow-profile conveyor drives, and multi-axis gantry systems where available depth behind the output shaft is limited, EP-ZDWE places the motor perpendicular to the output — either left/right or up/down — reclaiming the axial space that an inline motor would otherwise consume.

The bevel input stage introduces one additional gear mesh compared to the inline EP-ZDE, reducing single-stage efficiency from 96% (EP-ZDE) to 94% — a minor trade-off that Korean machine designers readily accept in exchange for the installation footprint reduction. The output shaft, round flange, bearing arrangement, lifetime lubrication, and IP54 sealing are identical to EP-ZDE of the same frame size, ensuring the output-side installation is a direct carryover.

Three Engineering Situations Where EP-ZDWE Is the Correct Choice

⚠ Right-Angle Input Cautions: The motor input direction must be specified at the time of ordering — the bevel gear orientation is set at manufacture and cannot be changed in the field. Do not attempt to rotate the bevel stage housing to change the input direction. Do not apply axial force to the bevel stage input shaft during motor installation — seat the motor face squarely. Maintain cable management to prevent cable tension pulling the motor connector during machine travel.

✔ Zero Maintenance — Bevel Stage Included: The EP-ZDWE factory-sealed lifetime lubrication covers both the bevel input stage and the planetary gear stages in a single sealed housing. No separate bevel gear oil fill, no level check, no scheduled lubrication for the bevel stage. The entire gearbox — input bevel and planetary output — runs on factory-injected lifetime grease for the full 20,000-hour rated life.

Compact CNC Machine Tool Headstocks — Rotary Axis Drive

Korean compact 5-axis machining centre builders use EP-ZDWE-80 and EP-ZDWE-120 for A-axis and B-axis rotary table drives in machines where the column depth behind the rotary axis is constrained by the machine column cross-section. A typical Korean 5-axis compact machining centre column has 220–250 mm of available depth behind the A-axis flange face — insufficient for a 1 kW servo motor + EP-ZDE-80 at 264 mm combined. EP-ZDWE-80 reduces the axial depth to 184.5 mm (1-stage), with the motor exiting laterally within the available column width. Korean machining centre OEMs in Changwon and Incheon report EP-ZDWE enabling column cross-section reductions of 80–100 mm across product lines that drive down machine weight and price.

Collaborative Robot Wrist & Elbow Joints

Korean collaborative robot manufacturers designing sub-80 mm outer diameter arms use EP-ZDWE-60 for wrist roll (rotation about the arm axis) drives. An inline motor + planetary gearbox at the wrist joint requires the motor to protrude beyond the wrist end-effector mounting flange — increasing the effective arm length and reducing the robot's reach-to-depth ratio. EP-ZDWE-60 routes the motor perpendicular to the wrist axis, keeping the arm outer diameter governed by the gearbox body (Φ60 mm) rather than the motor outer diameter. For the square-flange right-angle variant for wrist joints using plate-mount structure, see the EP-ZDWF series.

High-Speed Gantry Laser Cutting — Compact Y-Axis Carriage

Korean fibre laser cutting system manufacturers designing narrow-profile Y-axis carriages for systems cutting sheet metal up to 4 m wide use EP-ZDWE-80 for the carriage drive axis. The narrow carriage profile reduces the moving mass and moment of inertia of the Y-axis, enabling higher acceleration rates and shorter cycle times. With the motor exiting sideways from the carriage, the cable management chain can run parallel to the Y-axis travel — a cleaner layout than the axially-protruding motor of an inline configuration where the cable chain must accommodate the motor length as an obstacle.

Narrow-Profile Conveyor & Sorting Systems

Korean e-commerce fulfilment and parcel sorting system integrators use EP-ZDWE-60 for drive rollers on narrow-pitch conveyor sections where the belt-width-to-gearbox-depth ratio is constrained. On a 150 mm wide conveyor section, an inline motor + planetary gearbox protruding 260+ mm from the frame would require a larger housing or cross-beam. EP-ZDWE-60 fits within the conveyor frame depth with the motor exiting downward or sideways between adjacent conveyor modules — a common design in Korean high-density sortation conveyor systems at fulfilment centres in Incheon, Suwon, and Bucheon.

Multi-Axis Semiconductor Wafer Transport — Compact Arm Joints

Korean semiconductor equipment manufacturers designing atmospheric-end multi-axis wafer transport robots for 300 mm wafer handling use EP-ZDWE-60 for elbow and shoulder joints where the robot arm link length is constrained by the equipment front-opening unified pod (FOUP) load-port geometry. The sealed EP-ZDWE-60 passes cleanroom particle contamination evaluation (ISO 14644-1 Class 7) — the factory-sealed grease generates no detectable particles from the bevel stage during normal operation. Note that the higher backlash of EP-ZDWE (≤30 arcmin, 60-frame) versus EP-ZDE (≤8 arcmin) is acceptable for position-controlled wafer transport robots where the servo feedback loop compensates for gearbox backlash through closed-loop position control.

Medical Imaging & Diagnostic Equipment — Compact Axis Drives

Korean medical device manufacturers designing CT scanner gantry rotation drives and surgical robot arm joints use EP-ZDWE-60 and EP-ZDWE-80 for axes where the gantry housing outer profile is constrained by patient clearance requirements and IEC 60601 medical electrical equipment enclosure dimensions. The perpendicular motor arrangement allows the gantry or arm cross-section to be optimised for the minimum volume that meets the structural load requirements, rather than being dictated by the combined motor + gearbox inline length. The lifetime-sealed lubrication meets medical equipment maintenance-interval requirements.

• ✔Right-angle input servo gearbox bevel stage gear contact verified — tooth flank engagement measured per production batch
• ✔Backlash measured per unit at ±3% of rated output torque — measurement certificate with every order
• ✔Full-load torque test at rated output torque for each unit before shipment
• ✔IP54 ingress verification per IEC 60529 — every production batch
• ✔Material certificate and dimensional drawing provided with every delivery

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EP-ZDWE-120 at 20:1 two-stage for the A-axis rotary table on our compact 5-axis VMC. Previous machine generation used EP-ZDE-120 with the motor in-line — the motor + gearbox combination was 321 mm, forcing a 380 mm column cross-section to provide clearance. With EP-ZDWE-120 the axial depth is 277 mm (2-stage), the motor exits laterally, and we reduced the column section to 300 mm. That 80 mm column width reduction saved 22 kg per machine across a production run of 60 units. Korea Ever-Power confirmed the input direction (motor-right) and input flange for our Mitsubishi HG-SR motor in 1 business day.

EP-ZDWE-60 at 16:1 two-stage for the wrist roll joint of our 6-axis collaborative robot. Target wrist outer diameter was 72 mm — impossible with an inline motor at this torque level. EP-ZDWE-60 (Φ60 mm body) allowed us to achieve a 68 mm wrist outer diameter with the motor exiting upward along the forearm. We initially had concerns about the <35 arcmin 2-stage backlash, but our position control loop compensates the backlash contribution and joint positioning is within spec for our ISO 9283 robot accuracy class. Lifetime lubrication on both the bevel and planetary stages was essential — our robot operates in a food processing environment where maintenance access is restricted and grease contamination is a compliance issue.

EP-ZDWE-80 at 10:1 single-stage for the Y-axis of a narrow-carriage fibre laser cutting system — 3 m × 8 m working area, 120 m/min feed rate. Carriage profile width budget was 160 mm (constrained by the guide rail centres). An inline EP-ZDE-80 with our 400 W Yaskawa motor would have protruded 246 mm axially — requiring a wider carriage and changing the guide rail design. EP-ZDWE-80 has L1 of 184.5 mm with the motor exiting sideways within the 160 mm carriage, and the cable chain runs axially without obstacle. Now 18 months in production at 2 shifts per day — no issues with the bevel stage, noise settled after the first week of operation.

EP-ZDE Series — Inline Input, Round Flange

The coaxial inline version of EP-ZDWE — same round flange output and torque ratings, motor in line with output shaft. Offers <8 arcmin backlash (vs <25–30 arcmin for ZDWE) and 96% single-stage efficiency (vs 94% for ZDWE). Choose EP-ZDE when axial space permits and minimum backlash or maximum efficiency is the priority.

EP-ZDWF Series — Right-Angle Input, Square Flange

Identical to EP-ZDWE in all performance specifications — same right-angle bevel input, same torque ratings, same backlash — but with a square output flange (□60–□175 mm) for plate-mount installation. Choose EP-ZDWF when you need the axial space saving of EP-ZDWE and a flat-plate bolt-down output mounting rather than a bore-mount round flange.

EP-ZDS Series — High Stiffness, Heavy Load

When EP-ZDWE-160 at 800 N·m is not sufficient — EP-ZDS delivers up to 1,800 N·m (190-frame) with inline input, square flange, IP65 protection, torsional stiffness up to 130 N·m/arcmin, and 28,000 N maximum axial force. Note: EP-ZDS is inline only; for heavy loads with right-angle motor input, contact Korea Ever-Power for a custom configuration.

QHow much axial space does EP-ZDWE actually save compared to EP-ZDE?

The axial saving depends on the servo motor length, which varies by brand and power rating. For a typical 400 W servo motor with a 100 mm body length: EP-ZDE-80 at 1-stage gives 144 mm gearbox + 100 mm motor = 244 mm total axial depth. EP-ZDWE-80 at 1-stage gives 184.5 mm total axial depth (the motor exits sideways) — a saving of approximately 60 mm, or ~25%. With a larger 750 W motor of 130 mm body length, the saving becomes 130 mm — approximately 40%. The Korea Ever-Power application team calculates the exact axial saving for your specific motor model at no charge before order placement.

QCan I change the motor input direction after installation — left to right, for example?

No. The motor input direction (left, right, up, or down) is set by the bevel gear stage orientation at the time of manufacture and cannot be changed in the field without returning the gearbox to the manufacturer. The bevel pinion and ring gear are assembled in a fixed orientation relative to the output shaft. If your machine design requires flexibility in motor direction during the product development phase, specify this requirement to Korea Ever-Power before ordering — we can supply a sample unit in each required input direction for design evaluation.

QWhy is the backlash of EP-ZDWE wider than EP-ZDE — is this a quality issue?

No — the wider backlash is a characteristic of the right-angle input design, not a quality deficiency. The bevel gear input stage adds its own angular clearance (the bevel gear tooth clearance) to the backlash of the planetary gear stage. This is inherent to all right-angle bevel-input gearboxes, including competitor products. If your application requires <8–12 arcmin backlash and axial space permits, the inline EP-ZDE is the correct selection. EP-ZDWE is the right choice when the spatial constraint takes priority — the backlash specification of <25–30 arcmin (1-stage, 80–160 frame) is fully adequate for position-controlled servo axes where the servo feedback loop compensates for gearbox backlash.

QIs there a 40 mm frame available for EP-ZDWE, and what are the alternatives?

No — EP-ZDWE starts at 60 mm frame. The 40 mm frame size is only available in the inline series: EP-ZDE-40 and EP-ZDF-40. For applications requiring a 40 mm frame with a right-angle motor input, the axial saving from a right-angle input at this small frame size is limited (the motor length typically dominates the gearbox length) — Korea Ever-Power recommends evaluating whether the 60 mm frame EP-ZDWE meets the torque requirement first, before specifying a 40 mm frame.

QDoes the bevel stage require separate lubrication or maintenance?

No. The EP-ZDWE factory-sealed lifetime lubrication covers both the bevel input stage and the planetary gear stages in a single sealed housing. There is no separate oil reservoir for the bevel stage, no oil level gauge, no scheduled oil change for the bevel gears. The factory-injected grease lubricates the bevel gear tooth flanks and the bevel stage bearing throughout the 20,000-hour rated life. Do not add lubricant — the sealed housing has no fill port. A light audible hum from the bevel stage during the first 10–15 minutes of initial operation is normal run-in behaviour and will diminish as the tooth flanks burnish.