EP-HRD75B Harvester Rear-Drive Gearbox Type B — Five-Ratio Transmission with Brake Drum

EP-HRD75B Harvester Rear-Drive Gearbox Type B — Product Overview

Same Proven Drivetrain, Different Housing

Combine harvester manufacturers use several distinct rear-axle frame architectures, each with its own gearbox mounting interface. The EP-HRD75B addresses harvesters whose rear-axle geometry cannot accept the EP-HRD75A’s Type A housing. Inside, the EP-HRD75B is identical to the Type A: the same five-ratio gear set covering 248 to 595 rpm output, the same 75 KW continuous power rating from a 500 rpm input, and the same integrated brake drum providing consistent stopping authority across all five gears.

Type B Mounting Geometry

The Type B housing features a reconfigured mounting flange profile and bolt pattern that matches a different family of Korean and Asian combine harvester rear-axle designs. The housing exterior shape, fastener locations, and clearance envelope differ from Type A to accommodate the specific frame members, axle housings, and ancillary component positions found in Type B harvester architectures. All internal dimensions — bearing bores, gear centers, spline interfaces, and oil galleries — remain identical.

Five Ratios for Complete Harvest Flexibility

The EP-HRD75B provides the same five field-selectable ratios as the Type A: deep reduction (2.02 : 1 at 248 rpm) for maximum traction in wet paddy, standard harvesting (1.5 : 1 at 333 rpm), light-crop fast advance (1.0625 : 1 at 471 rpm), and road transport overdrive (0.84 : 1 at 595 rpm). This 2.4× speed spread from lowest to highest gear gives the operator complete control over ground speed and wheel torque regardless of crop conditions, soil moisture, or terrain gradient.

Complete Specification — All Five Gear Ratios

EP-HRD75A vs. EP-HRD75B — Complete Variant Comparison

Type A and Type B are housing variants of the same internal drivetrain. Choosing the correct variant is purely a mechanical fitment decision based on your harvester’s rear-axle mounting geometry:

Type B Housing Design — Engineered for Alternate Axle Architectures

Why Two Housing Types Exist

Korean and Asian combine harvester manufacturers use two predominant rear-axle frame architectures. Some position the differential housing, hydraulic lines, and structural bracing in a configuration that requires the gearbox mounting flange on one side of the frame, while others route these components differently, requiring the gearbox to mount from the opposite side with a different bolt layout and clearance profile. Rather than forcing harvester builders to redesign their frames around a single gearbox shape, Korea Ever-Power provides both housing variants so the gearbox adapts to the machine — not the other way around.

Reconfigured Mounting Flange

The EP-HRD75B’s Type B mounting flange relocates the bolt holes and pilot surfaces to match the second family of harvester rear-axle designs. The bolt pattern spacing, pilot bore diameter, and flange thickness are all specific to Type B. CNC machining ensures that every EP-HRD75B housing produced matches the Type B specification within ±0.02 mm, guaranteeing drop-in replacement compatibility without shimming, re-drilling, or field adaptation.

Modified Clearance Envelope

Beyond the mounting interface, the Type B housing reshapes its external profile to clear the frame members, axle tubes, hydraulic fittings, and brake linkages that occupy different positions in Type B harvester architectures. The internal dimensions — bearing bores, gear center distances, oil capacity, and shaft positions — are unchanged. This means any performance data, maintenance procedure, or service interval that applies to the EP-HRD75A also applies to the EP-HRD75B. Only the mounting and clearance geometry differs.

Harvester Model Compatibility — How to Confirm Type B Fitment

Selecting the wrong housing type results in a gearbox that physically cannot mount to your harvester. Follow this three-step verification process before ordering:

Field Application Scenarios

Korean Rice Harvest on Type B Combines

A significant portion of the Korean combine harvester fleet uses Type B rear-axle architectures, particularly models produced by certain domestic manufacturers during specific production periods. These machines need the EP-HRD75B for rear-drive replacement or upgrade. The five-ratio range provides the same harvest-season versatility as the Type A variant: maximum traction in waterlogged paddies (Gear 1), standard harvesting in typical rice fields (Gear 3), and road transport between fields (Gear 5).

Aftermarket Fleet Upgrades

Agricultural cooperatives and contract harvesting companies operating mixed fleets of Type A and Type B harvesters can standardize on the EP-HRD75 platform across all machines. Both variants share identical internal components, maintenance procedures, oil specifications, and brake parts — only the housing differs. This platform commonality reduces spare parts complexity, simplifies technician training, and enables internal parts sharing between Type A and Type B units in the field.

Southeast Asian Harvester Markets

Korean-designed combine harvesters exported to Vietnam, Thailand, and the Philippines include both Type A and Type B rear-axle configurations depending on the model variant and destination market. Aftermarket parts dealers in these countries stock both EP-HRD75A and EP-HRD75B to serve the full installed base. The EP-HRD75B’s five-ratio flexibility is particularly valued in Southeast Asian rice paddies where monsoon-season field conditions vary dramatically between morning and afternoon harvesting.

Why Choose the EP-HRD75B

Installazione e manutenzione

Mounting Procedure

❶ Lift the EP-HRD75B into position on the harvester’s rear-axle frame. Align the Type B mounting flange with the existing bolt holes and pilot bore.

❷ Insert all mounting bolts finger-tight. Torque in a star pattern to specification. Re-check torque after the first 8 operating hours.

❸ Connect the input shaft to the harvester’s engine-output albero motore coupling. Verify the brake drum aligns with the brake caliper or shoe assembly.

❹ Connect the output shaft to the rear-axle differential. Attach the gear selection linkage and verify all five ratios engage with positive detent feel.

❺ Fill gear oil (SAE 80W-90 GL-5), test brake engagement, and perform a low-speed field test in each gear before commencing harvest.

Maintenance Schedule

◆ Before every harvest day — Check oil level; test brake engagement and release; verify gear selection linkage.

◆ After first 100 hours — First oil change; inspect brake drum lining thickness.

◆ Every 500 hours / annually — Full oil change; inspect brake components; check gear selector detents.

◆ Every 1,000 hours — Inspect all gear meshes; check bearing play; measure brake drum for wear limits.

◆ End of harvest season — Top off oil; release parking brake to prevent drum-to-shoe bonding during storage.

Companion Products & Seasonal Equipment

Complete Harvester Driveline

Korea Ever-Power manufactures a complete family of harvester gearboxes: the EP-HRD75A/B rear-drive pair (five ratios, 75 KW), the EP-HRDF50 front-drive unit (eleven ratios, 50 KW), the EP-HRDR50/EP-HRDR60 direct-ratio rear-drive units, and the EP-HRD30 compact 30 KW model. Contact our engineering team for a complete driveline specification matched to your combine model.

Off-Season Equipment

Between harvest seasons, many Korean farms equip tractors with rotary cultivator gearbox assemblies for spring tillage and cambio per pressa per balle rotonde units for autumn straw management. Korea Ever-Power supplies the complete seasonal equipment range.

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