EP-B50S Baler Reduction Gearbox — 50 KW, 1.5:1 Speed Reduction for Baler Subsystems

EP-B50S Baler Reduction Gearbox — Product Overview

The Exception in the Baler Range — Reduction, Not Increase

Every other gearbox in Korea Ever-Power’s baler range is a speed increaser — boosting 540 rpm PTO input to 1,100+ rpm for pickup reels and chamber rollers. The EP-B50S is the deliberate exception. Its 1.5 : 1 reduction ratio slows the PTO speed from 540 to 360 rpm, providing the controlled, high-torque output that specific baler subsystems need: straw feed mechanisms that must pull material at precisely regulated speed, chamber-rotation drives that turn the bale core at controlled RPM, and auxiliary drives for hydraulic pumps or binding-system geartrains.

Where 360 RPM Fits in the Baler Driveline

In a modern round baler, the main driveline runs at high speed (1,150–1,234 rpm from a speed-increaser gearbox) to power the pickup reel and chamber rollers. But secondary systems — the straw pre-cutter, the bale density control mechanism, and the twine arm actuator — operate at lower speeds with higher torque. Rather than using lossy friction-based speed reducers or complex hydraulic circuits to slow these subsystems, the EP-B50S provides a clean, mechanical speed reduction from a separate PTO take-off point, delivering exactly 360 rpm with 1.5× torque multiplication.

Compact 405.5 mm Package

The EP-B50S packs its reduction gear set into a compact housing measuring just 405.5 mm in total length. The 6×27×34×7 spline input and 8×32×38×6 spline output provide reliable, backlash-free torque transfer in both directions. The additional Ø90 mounting flange (4-Ø9 bolts) at the base secures the gearbox rigidly to the baler frame, preventing housing movement under the cyclic loading of baler operation.

Full Technical Specifications

Why Some Baler Systems Need Speed Reduction

A modern round baler is not a single-speed machine — it contains multiple subsystems that operate at different speeds. The high-speed pickup and chamber rollers need 1,100+ rpm (served by speed-increaser gearboxes), but other critical systems need controlled, slower speeds with higher torque:

Compact Reduction Architecture — 1.5 : 1 in 405.5 mm

Right-Angle 90° Configuration

The EP-B50S uses the same right-angle spiral bevel gear architecture as Korea Ever-Power’s tillage gearboxes, but optimized for the baler installation environment. The 90° shaft turn converts the horizontal PTO input into the vertical or angled output orientation that baler subsystems typically require. The 1.5 : 1 gear pair provides a moderate reduction that keeps the output speed close to PTO speed while delivering meaningful torque multiplication — a balance point that neither a 1 : 1 angle gear nor a deeper 2 : 1 reducer achieves.

6×27×34×7 Input Spline

The EP-B50S uses a 6×27×34×7 spline input — a six-tooth profile with 27 mm minor diameter, 34 mm major diameter, and 7 mm tooth width. This spline specification is widely used in Korean baler driveline components and connects directly to standard PTO drive shaft assemblies. The six-tooth involute form distributes torque evenly across all teeth, providing the same spline life advantage as the larger involute profiles used on Korea Ever-Power’s higher-power gearboxes.

Dual Output Interface

The output end provides both an 8×32×38×6 spline for direct coupling to baler subsystem input shafts and a Ø35 mm keyed shaft with Ø110 mm flange face for flanged connections. The Ø90 base mounting flange (4-Ø9 bolts) secures the housing to the baler frame independently of the output connection, separating structural loads from drivetrain forces for cleaner power transmission and longer bearing life.

Key Dimensions & Mounting Interface

Speed Reducer vs. Speed Increaser — When Each Is Needed in a Baler

Understanding which baler subsystem needs which type of gearbox prevents costly selection errors:

Field Application Scenarios

Baler Pre-Cutter Drive

Many Korean and Japanese round balers include an optional straw pre-cutter that chops incoming straw into shorter segments for denser, more uniform bales. The pre-cutter knife rotor requires 300–400 rpm with high torque to slice through thick straw windrows. The EP-B50S delivers 360 rpm with 1.5× torque multiplication — enough cutting force for even wet, heavy rice straw without stalling the pre-cutter mechanism.

Bale Wrapping & Binding Systems

The twine wrapping arm and net dispensing mechanism operate at controlled speeds with consistent torque to maintain wrap tension throughout the binding cycle. Direct PTO speed (540 rpm) is too fast for precise wrap control, causing uneven coverage and loose bales. The EP-B50S’s 360 rpm output provides the controlled rotation speed that allows tight, uniform wrapping even on irregularly shaped bales formed from mixed crop residue.

Auxiliary Hydraulic Pump Drives

Some balers use a dedicated hydraulic pump driven from a secondary PTO take-off to power the bale ejection system, tailgate actuators, and density control cylinders. These pumps typically operate most efficiently at 300–500 rpm — slower than PTO speed but faster than the engine-driven pump. The EP-B50S provides a clean mechanical drive at 360 rpm, eliminating the need for an additional hydraulic motor circuit and simplifying the baler’s overall hydraulic system architecture.

Why Choose the EP-B50S

Installation & Maintenance

Mounting Procedure

❶ Secure the EP-B50S to the baler frame using the Ø90 base mounting flange (4-Ø9 bolts). Torque bolts in a star pattern to specification.

❷ Connect the output (8×32×38×6 spline or Ø35 keyed shaft) to the baler subsystem’s input coupling. Verify full engagement depth.

❸ Connect the PTO drive shaft or baler internal drive linkage to the 6×27×34×7 spline input. Install the safety guard where applicable.

❹ Fill gear oil (SAE 80W-90 GL-5) and run a 5-minute idle test. Verify smooth 360 rpm output rotation, zero leaks, and no abnormal noise before engaging the baler subsystem under load.

Maintenance Schedule

◆ Before every baling session — Check oil level; inspect input and output splines.

◆ After first 100 hours — First oil change: drain, flush, refill.

◆ Every 500 hours / annually — Full oil change; inspect magnetic drain plug (standard reducer interval — not the 400-hour speed-increaser interval).

◆ Every 1,000 hours — Inspect spline wear; check base flange bolt torque; examine seal condition.

◆ End of straw season — Top off oil; apply corrosion inhibitor to exposed shaft surfaces.

Companion Products & Driveline Components

Speed-Increaser Pairing

The EP-B50S is designed to work alongside a speed-increaser gearbox in the same baler. Pair it with an EP-1800B, EP-2250B, EP-B80, or EP-B100 from the Korea Ever-Power round baler gearbox range to create a dual-speed baler driveline: high-speed output for the main drive (1,150–1,234 rpm) and reduced-speed output for auxiliary subsystems (360 rpm). Both gearboxes connect to the same tractor PTO through appropriate drive shaft arrangements.

Off-Season Tillage Gearboxes

Tractors equipped for baling duty during straw season typically switch to rotary cultivator gearbox assemblies for spring and summer tillage. Korea Ever-Power manufactures the complete range of intermediate, reduction, and speed-increaser gearboxes to keep your tractor productive across every season.

Frequently Asked Questions

Customer Reviews & Field Reports