EP-HC-75 Rotary Cultivator Gearbox – 75 to 125HP, Four-Ratio Heavy Duty Series
★ Flagship Heavy-Duty Rotary Cultivator Gearbox — 75–125HP, Four Ratio Options, One Platform That Handles Every Field Condition
그만큼 EP-75 is the highest-capacity model in Korea Ever-Power’s rotary tiller gearbox range — four selectable reduction ratios covering 1:1.6 to 1:3, power ratings from 75HP to 125HP, and module grades from 5.35 to 7.5 for true heavy-duty tooth strength. The 3/8 Z6 PTO input runs at 540RPM; the optic axis output connects directly to standard cultivator rotor shafts. Housed in GGG50 nodular cast iron, weighing 37kg, and 100% load-tested before dispatch. For Korean and Japanese farmers running 80–120HP utility tractors on full-width tillage operations, and for OEM manufacturers building large-scale rotavators for the Asia-Pacific market, the EP-75 is the correct specification — not an upgrade from it.
EP-75 Rotary Cultivator Gearbox — Series Overview
EP-75 · 75–125HP · Ratios 1:1.6–1:3 · 37 kg
그만큼 EP-75 rotary cultivator gearbox occupies the top of the HC series tiller range. Where the EP-0 and EP-9.310 cover the 30HP compact-tractor segment, the EP-75 addresses the demands of full-scale commercial tillage: fields measured in hectares rather than ares, tractors in the 75–125HP class, and tillage depths pushing 200mm or more in one pass. This is not the gearbox for occasional cultivation — it is built for operations where the machine runs day after day at close to rated load, across soil types from paddy clay to volcanic loam.
Four ratio configurations are available within the EP-75 platform: 1:3 / 1:2.83 / 1:1.85 / 1:1.6. Unlike the EP-RC31 where ratio selection is primarily about blade tip speed, rotary tiller ratio selection is about the balance between rotor RPM and tillage depth. Lower ratios (1:3) reduce rotor speed relative to PTO input, giving the tines more time in contact with the soil per revolution — critical for deep cultivation and clod-breaking in hard or stony ground. Higher ratios (1:1.6) increase rotor speed for shallow, high-throughput tillage of already-worked soil or light cover crop incorporation.
The housing is machined from GGG50 nodular cast iron and weighs 37kg — the heaviest unit in the HC cultivator series. That mass is not deadweight; it is the structural investment required to contain the sustained bending and torsional loads generated when the rotor encounters buried stones, hardpan layers, or the root mats typical of paddock-edge tillage. The 3/8 Z6 spline input and optic axis output are both ISO-standard dimensions, ensuring the EP-75 connects to the full range of tractor PTO shafts and standard cultivator rotor tube diameters used across South Korea, Japan, and Southeast Asia without custom adapters.
Replacement Reference: The EP-75 is engineered to match the specification of comparable Bondioli & Pavesi, Comer Industries, and Brevini Power Transmission tiller gearbox models in the 75–125HP / 1:2.83–1:3 ratio class. Korea Ever-Power is not affiliated with or an authorised distributor of these brands. Model references are provided solely to assist customers in identifying compatible specifications and do not imply any counterfeit or infringing relationship.
Technical Specifications — All Four EP-75 Ratio Configurations
All figures below are factory-verified from the official EP-75 product datasheet. Note how gear module increases as ratio decreases: the 1:1.6 configuration uses M7.5 — the coarsest pitch in the HC series — because at this ratio the rotor-side gear carries both the higher torque amplification and the highest bending loads from tine-to-obstacle contact. This progressive module scaling is a deliberate engineering choice, not a cost measure, and it is what distinguishes a purpose-built heavy duty rotary tiller gearbox from a standard bevel-gear unit pressed into service. 
| 매개변수 | Config 1 | Config 2 | Config 3 | Config 4 |
|---|---|---|---|---|
| 속도비 | 1 : 3 | 1 : 2.83 | 1 : 1.85 | 1 : 1.6 |
| Teeth Count | 12 / 36 | 34 / 12 | 33 / 20 | 24 / 15 |
| 기어 모듈 | 6.0 | 5.35 | 5.5 | 7.5 |
| 정격 전력 | 75 HP | 75 HP | 100 HP | 125 HP |
| Rotor Output RPM (at 540 input) | ≈ 180 | ≈ 191 | ≈ 292 | ≈ 338 |
| 정격 입력 속도 | 540 RPM — all configurations | |||
| 입력 샤프트 | 3/8 Z6 spline (ISO 500) | |||
| 출력축 | Optic axis (plain round shaft, Φ33) | |||
| 하우징 소재 | Nodular cast iron GGG50 | |||
| 순중량 | 37 kg | |||
EP-75 housing dimensions: 223 × 202 × 111 mm (approx.)
The EP-75 engineering drawing dimensions confirm its physical footprint: approximately 223mm across the widest housing face, 202mm mounting height, and 111mm depth. These dimensions matter when fitting the gearbox into a cultivator chassis: the EP-75 is larger than the EP-9.311 series but uses the same output shaft standard (optic axis, Φ33), so it can replace a smaller-capacity unit on an upgraded machine without modifying the rotor coupling.
The multi-output flange design visible in the photograph accommodates both single-output (standard rotary tiller) and dual-output (wide-rotor) shaft configurations. The bearing seats are line-bored to H7 tolerance after assembly — a manufacturing step that ensures the bevel gear mesh stays within the designed contact zone under the asymmetric loads imposed by single-side tine engagement on uneven terrain. This step adds cost but is non-negotiable on a gearbox rated to 125HP, where even 0.1mm of bearing-seat misalignment can reduce gear life by 40–60%.
The HC Rotary Tiller Gearbox Family — Where EP-75 Fits
Korea Ever-Power supplies a complete family of rotary cultivator gearboxes from 30HP to 125HP. Understanding where the EP-75 sits in this range helps confirm it is the right choice — and identifies the alternatives if your power requirement falls lower.
| 모델 | Power Range | Ratio(s) | 무게 | Best For |
|---|---|---|---|---|
| EP-0 | 30 HP | 1 : 2.9 | 13.5 kg | Mini-tractor, garden beds, narrow plots |
| EP-9.310 | 30 HP | 1 : 3 | 18kg | Standard 30HP compact tractor cultivators |
| EP-9.311 | 50 HP | 1 : 3 | 21 kg | Mid-size farm cultivators, 40–55HP tractors |
| EP-9.312 | 62 HP | 1 : 3 | 27kg | Upper mid-range, 55–65HP utility tractors |
| EP-75 ← this product | 75–125 HP | 1:3 / 1:2.83 / 1:1.85 / 1:1.6 | 37 kg | Large tractor, full-width cultivation, commercial farms |
| EP20100.131.00 | 100 HP | 1 : 31 | 58kg | Ultra-high torque vertical-shaft specialist applications |
If your tractor is below 75HP, the EP-9.311 (50HP) or EP-9.312 (62HP) is the more appropriate specification — do not over-specify a gearbox rated for a higher power class than your tractor can deliver, as the bearings and seals run less efficiently at light loads over extended periods.
How to Choose the Right Ratio for Your Tillage Conditions
Rotary tiller ratio selection is fundamentally different from mower ratio selection. With a mower, you want blade tip speed. With a 회전식 경운기 기어박스, you want rotor RPM balanced against tillage depth, soil type, and forward travel speed. The four EP-75 configurations map to distinct field scenarios:
≈ 180 RPM rotor output · 75HP
Lowest rotor speed in the range. Each tine spends the most time in ground contact per revolution — ideal for breaking hardpan layers, deep incorporation of organic matter (straw, compost), and first-pass tillage of land transitioning from fallow. Used widely on Korean upland rice-adjacent dry fields before transplanting season and in Japanese vegetable districts with heavy clay subsoils.
≈ 191 RPM rotor output · 75HP
The closest EP-75 equivalent to the EP-9.311/9.312 ratio class, but with 25–65% more rated power. Suited to standard 150–180mm tillage depth in loam and sandy-loam soils across the Korean peninsula's inland agricultural zones and Japan's alluvial plains. This is the most commonly specified ratio for general-purpose commercial farm cultivation in the Asia-Pacific market.
≈ 292 RPM rotor output · 100HP
Higher rotor speed for shallower, faster tillage passes. Used in cover crop termination, seedbed preparation for direct-seeded crops (corn, soybean, sorghum), and secondary tillage after initial breaking. The 100HP power rating aligns with the larger 4WD tractors operated on Korea's flatter agricultural land and Japan's northern island farm-scale operations.
≈ 338 RPM rotor output · 125HP
Fastest rotor speed in the EP-75 range. Suited to shallow mulching (50–100mm), seedbed finishing after primary tillage, and high-throughput passes on large fields where operational speed matters more than tillage depth. Module 7.5 gearing handles the 125HP input load at this ratio without tooth fatigue. Used by large commercial operators in Vietnam's Mekong Delta rice production areas and Thailand's cassava-growing regions.
Practical rule of thumb: Match the ratio to your primary soil condition. For most Korean and Japanese farms tilling to 150mm or more in medium to heavy soil, the 1:2.83 or 1:3 configurations are the standard choice. For shallow seedbed work or high-speed secondary tillage, consider 1:1.85 or 1:1.6. If you are unsure, contact Korea Ever-Power's technical team with your tractor HP, target tillage depth, soil type, and working width — we will recommend the correct ratio configuration before you order.
Heavy-Duty Construction — Why 37kg Is Worth Carrying
GGG50 Nodular Cast Iron
The entire housing — top cover, main body, and bearing flanges — is cast from GGG50 ductile iron. In rotary tiller service, the housing experiences sustained torsional load and intermittent shock from tine-to-stone contact. Nodular iron's elongation at break (18% for GGG50 vs. 0.5% for grey iron) means the housing deforms microscopically under peak loads rather than fracturing — a critical property for a gearbox that cannot be stopped mid-field for housing replacement.
Progressive Module Gearing (M5.35–M7.5)
The EP-75 uses a larger gear module for higher-ratio (higher-torque) configurations. Module 7.5 on the 1:1.6 variant has a tooth face area approximately 75% larger than Module 4.0 used in lighter units. This directly translates to higher bending strength and contact fatigue resistance — the two primary failure modes for bevel gears in heavy-duty tiller service. Gears are carburised and quench-hardened to HRC 58–62 case depth 0.8–1.2mm on all configurations.
Multi-Point Bearing Arrangement
The heavy-duty bevel gear set requires bearing support on both sides of the crown gear — not just the drive side. The EP-75 uses tapered roller bearings on the primary shaft and deep-groove ball bearings on the secondary shaft, a combination that handles the mixed radial and axial loads generated when the rotor engages non-uniform soil layers at varying forward speeds without inducing shaft deflection that would change the gear mesh contact pattern.
Sealed for Soil Contamination
Rotary tiller gearboxes operate in the most contaminated environment of any agricultural drive unit — fine soil, crop residue, stone dust, and water are present at every operating hour. The EP-75 uses dual-lip NBR oil seals at all shaft exits with reinforced lip geometry that maintains sealing contact even when the shaft runs with the slight lateral movement typical of worn rotor tube bearings, preventing the soil ingress that accelerates bearing abrasion.
High-Capacity Oil Sump
The EP-75 housing volume accommodates a larger oil charge than the smaller EP-9 series — approximately 600–700ml of SAE 90 GL-4/GL-5. The increased oil volume provides a larger thermal buffer during sustained-load operation, keeping oil temperature lower and extending the effective lubrication interval. For operations in Thailand, Vietnam, or southern Japan where ambient temperatures regularly exceed 35°C, this thermal margin is a practical reliability factor, not just a specification number.
100% Pre-Dispatch Load Test
Every EP-75 unit is bench-tested at full rated load before packaging. The test specifically verifies gear mesh contact pattern under load (not visible at rest), bearing pre-load correctness, oil seal integrity under pressure, and noise level at the rated RPM. Any unit that fails any parameter is rebuilt before dispatch — not downgraded or shipped with a note.
Bevel-Gear Rotary Tiller Gearbox vs. Planetary Gearbox — Which One Do You Need?
Some heavy-duty applications prompt the question: why not use a planetary gearbox for high-torque rotary tillage? The comparison below provides an honest answer — both drive types have real advantages, and the choice depends on application priority rather than any single factor being superior.
| Factor | EP-75 Bevel Tiller Gearbox | 유성 기어박스 |
|---|---|---|
| Torque density | High — adequate for 125HP tiller use | Very high — optimal for extreme torque concentration |
| Shock absorption | Excellent — nodular iron housing, coarse module gears | Good — but ring gear more vulnerable to impact fracture |
| Ratio flexibility | 4 ratio options in same housing platform | Fixed ratio per unit; changing ratio requires new unit |
| Field repair | Simple — bevel gears and bearings accessible in field workshop | Complex — sun/planet/ring gear assembly requires specialist tools |
| Unit cost | Lower — simple two-gear bevel arrangement | Higher — multi-planet carrier precision machining |
| Choose when | Standard rotary tiller duty, cost-conscious purchasing, field-repairable requirement | Maximum torque density in minimum space; robotic/automation applications |
For standard rotary cultivator service up to 125HP, the EP-75 bevel-gear design is the correct choice for the majority of Korea Ever-Power's Asia-Pacific customers. Planetary gearboxes are typically specified in robotic arm joints, hydraulic motor final drives, and wind turbine pitch control — not in PTO-driven agricultural tillage where shock resistance and field repairability are the primary reliability factors.
Where the EP-75 Is Put to Work
🌾 Paddy-Adjacent Dry Field Preparation — Korean Upland Farming
Korea's mixed paddy-and-upland farming system — prevalent in Jeolla, Chungcheong, and Gyeongbuk provinces — requires the dry upland plots to be tilled deeply (160–200mm) in spring before garlic, onion, pepper, and root vegetable planting. The compact clay-loam soils of these regions, combined with the cold winters that harden the topsoil layer, demand high torque and sustained depth capability. The EP-75 at 1:3 ratio (180 RPM rotor, 75HP) handles these conditions as a standard work cycle — not as an edge-of-capacity operation. Large-scale operations in these zones run 80–100HP tractors on full-width (1.8–2.2m) cultivators, and the EP-75 is the gearbox that makes that width-and-depth combination viable.
🏔️ Volcanic Soil Cultivation — Hokkaido & Kyushu, Japan
Japan's Hokkaido island — the country's largest agricultural region by area — has significant volcanic ash-derived soil zones (Andosols) that are mechanically difficult: light and fluffy when dry, sticky and cohesive when wet, and prone to surface crust formation after rain events. These soils require higher rotor-to-soil contact time than mineral soils, making the lower-ratio EP-75 configurations (1:3 or 1:2.83) the standard specification for the large 80–110HP tractors operated on Hokkaido's commercial vegetable and potato farms. Similarly, Kyushu's sweet potato and tobacco growing areas in Miyazaki and Kagoshima prefectures use large-frame tillers for bed preparation where the EP-75 is the correct power class.
🌿 Cover Crop Incorporation — Multi-Season Rice Production
Across the Mekong Delta in Vietnam, the Chao Phraya basin in Thailand, and the lowland rice belts of the Philippines, multi-season rice farming leaves a heavy residue of straw, root mat, and volunteer vegetation between crops. Incorporation of this organic load before the next crop cycle requires both high rotor speed (to cut and fragment the material) and sufficient power to push through the mat at working speed. The EP-75 at 1:1.85 (292 RPM, 100HP) is specified on the larger tractor-mounted tillers used in commercial rice-farming operations in these regions for exactly this application. The 농업용 기어박스 in this duty cycle runs at sustained high load — the 37kg housing mass, high-capacity oil sump, and dual-lip seals are each contributing factors to the service reliability observed in these high-temperature, high-humidity environments.
🏭 OEM Large-Scale Rotavator Manufacturing
Several Korean and Southeast Asian agricultural machinery OEMs building wide-format (2.0–2.5m working width) rotary tillers for commercial sale specify the EP-75 as the centre gearbox in their product designs. The four-ratio platform allows a single product chassis to be offered at different performance tiers across different export markets, with the gearbox ratio being the only production-line variable. Korea Ever-Power's OEM supply programme for the EP-75 includes custom shaft dimensions, specific ratio selection, and private-label housing marking for volume customers. Contact our technical sales team with machine drawings for OEM quotations.
Installation Guide & Maintenance Schedule
Installation Checklist
- 1.Confirm tractor PTO speed is 540 RPM and input shaft is 3/8 Z6 spline.
- 2.Verify output (optic axis, Φ33) matches the rotor tube inner diameter of your cultivator.
- 3.Mount the gearbox to the cultivator frame using all four housing bolts torqued to specification. Do not run with fewer than four bolts engaged.
- 4.Fill to the oil level mark with SAE 90 GL-4/GL-5 gear oil — approximately 600–700ml. Do not overfill.
- 5.Run briefly at low PTO speed and inspect for leaks and abnormal noise before full-load operation.
- 6.Perform first oil change at 50 hours to clear break-in metallic particles.
Maintenance Intervals
Every 50 Hours (break-in only)
Drain and replace gear oil. Inspect drain oil for metallic particles — normal at break-in. Clean drain plug magnet if fitted.
Every 200 Hours
Change gear oil. Inspect input and output seal lips for oil film. Check all housing bolts for tightness. Wipe housing exterior to inspect for hairline cracks.
Every Season (or 500 Hours)
Remove gearbox and inspect bearing end-play. Check gear tooth contact pattern using gear marking compound. Replace both oil seals preventively if more than 500 hours since last seal replacement. Apply fresh rust inhibitor to bare metal.
Tropical Climate Note (Vietnam, Thailand, Philippines)
In ambient temperatures above 35°C, reduce oil change interval to every 150 hours. Check oil colour at each interval — dark brown is normal degradation; milky colour indicates water contamination from a seal failure requiring immediate attention.
Why Commercial Farmers and OEMs Choose Korea Ever-Power
Dedicated CNC gear machining and assembly — 3,800 m²
Korea Ever-Power Agricultural Machinery Co., Ltd. has supplied precision 농업용 기어박스 to the Asia-Pacific market for 19 years. Our 3,800 m² production facility in Taizhou — 90 engineers and production staff, CNC gear hobbing and grinding, controlled-atmosphere carburising, calibrated load test benches — represents the full chain of manufacturing capability required for heavy-duty products like the EP-75.
For commercial farm operators and OEM manufacturers in South Korea, Japan, and Southeast Asia, the advantages over sourcing equivalent European products are practical and measurable: shorter lead times (3–7 business days vs. 4–8 weeks), lower landed cost (typically 30–50% below comparable European pricing after freight and duties), and direct technical support without going through a distribution chain. Our team can confirm gear ratio suitability for your specific application before you order — something a distributor catalogue cannot do.
Complete Your Rotary Tiller Drive System
The EP-75 gearbox is the centre of the drive system, but optimal performance requires matched components at both ends of the power path.
