Model 4 Shaft Output Drives Planetary Gearbox

Universal Machinery Compatibility

Virtually all industrial driven components — conveyor drum shafts, mixer impeller hubs, auger flights, chain sprockets, gear couplings, and pump impellers — are designed to accept a keyed cylindrical or splined input shaft. The shaft output planetary gearbox connects directly to these components without custom adaptors.

Flexible Mounting Positions

The shaft output allows the gearbox to be foot-mounted, flange-mounted, or torque-arm mounted in any orientation — horizontal, vertical shaft-up, vertical shaft-down, or any angle — giving machine designers maximum freedom to optimise the drive package for space and maintenance access.

Easy Field Replacement

Because driven components simply slide onto the output shaft and are secured with a key/keyway, nut, or retaining ring, field replacement of a worn gearbox is fast — typically under two hours even in remote or confined locations. No special tooling, alignment equipment, or precision shimming required.

High Shaft Torque Capacity

The output shaft is a precision-forged or machined alloy steel component sized for the full rated output torque with an adequate safety factor. Splined output shafts distribute torque over multiple teeth, eliminating the keyway stress concentration and enabling higher torque transmission in the same shaft diameter versus a keyed shaft.

Motor Input

A hydraulic orbital or axial-piston motor (SAE flange) or electric motor (IEC B5) drives the sun gear at high speed via the splined or keyed input shaft connection on the motor mounting face.

Planetary Reduction

The sun gear drives three or more planet gears meshing with the fixed ring gear. The planet carrier rotates at reduced speed with multiplied torque — one stage for single reduction, two stages for double reduction up to 33.79:1.

Solid Shaft Output

The final planet carrier connects to the output shaft, which projects from the housing at the rated low speed with full output torque. The keyed or splined shaft inserts into the driven component hub to transmit torque.

Housing Reaction

The housing is bolted stationary to the machine frame (foot mount, flange mount, or torque arm), and reacts the gearbox torque into the machine structure while the output shaft rotates the driven component.

Optional Brake

An optional spring-applied parking brake on the input stage locks the output shaft when hydraulic or electric release pressure is removed — important for vertical shaft-down conveyor and mixer applications where backdriving must be prevented.

Direct Auburn Model 4 SD Replacement

Dimensionally verified against Auburn Gear Model 4 SD (MH677) drawings — output shaft diameter and spline, SAE motor flange pattern, oil port locations, and overall axial length. Bolt-on replacement in under two hours, zero machine modification required.

The Proven Conveyor and Mixer Drive

Auburn Gear's own documentation describes Model 4 Shaft Output Drives as continuously ordered for conveyors, augers, and mixers — a direct statement of market validation. Our unit delivers the same performance as the OEM product with 96 to 98% efficiency at a lower cost of ownership.

3,390 N·m — 2,900 N·m Continuous

Maximum intermittent output torque of 3,390 N·m (30,000 lb-in) with a recommended continuous operating level of 2,900 N·m (25,000 lb-in) — covering the vast majority of mid-size industrial conveyor and mixer drives powered by SAE B or C hydraulic orbit motors at 2,500 to 5,000 RPM.

Universal Shaft Configuration Options

Available with keyed cylindrical shaft (standard, most common), SAE splined shaft (for hydraulic motor-style coupling to driven components), and DIN splined shaft (for metric machinery). Custom shaft diameters, lengths, and keyway positions are available for OEM machine builders.

Wide Ratio Range from One Platform

Single-reduction (3.75:1 to 5.8:1) and double-reduction (13.06:1 to 33.79:1) variants share the same housing footprint and motor mounting interface. From fast conveyor belts at 3.75:1 to slow heavy paddle mixers at 32.76:1, one gearbox family covers the entire application range with stock availability on popular ratios.

Hydraulic and Electric Motor Ready

SAE A, B, and C hydraulic motor flanges for direct mounting of orbit motors (Char-Lynn, Danfoss, White Drive), axial-piston motors (Parker, Bosch Rexroth), or gear motors. IEC B5 electric motor adaptor plates for standard induction, inverter-duty, or servo motors. No separate adaptor hardware or coupling required in either configuration.

Multiple Mounting Configurations

The Model 4 shaft output drive mounts in any orientation: horizontal (most common for conveyor drives), vertical shaft-down (grain auger, screw conveyor sump discharge), vertical shaft-up (mixer agitator, paddle blender), and any angle in between. For vertical applications, contact our engineers to confirm adequate lubrication at the specified fill level.

Fully Reversible Operation

Reverse torque is obtained simply by reversing the hydraulic motor flow direction — no additional gear mechanism required. This full reversibility is essential for conveyors that need emergency reverse, mixers that reverse to prevent impeller fouling, and augers that back off under blockage. Equal torque capacity in both directions of rotation.

Output Shaft

One-piece forged or precision-machined alloy steel shaft — heat-treated for torsional and bending strength. Keyway is broached or milled after heat treatment to ensure dimensional accuracy. Splined variants are hobbed to DIN 5480 or SAE standard and profile-ground for accurate spline fit. Shaft end threaded for standard retaining nut.

Housing and Ring Gear

GGG-50 ductile iron housing provides impact resistance against conveyor frame shock and mixer starting torque spikes. The heat-treated ring gear is press-fit and positively retained within the housing — preventing ring gear rotation that can occur in competing designs under reverse torque or shock loading.

Planetary Gear Set

All sun, planet, and ring gears manufactured from 18CrNiMo7-6 alloy steel, vacuum carburized, case-hardened to 58-62 HRC, then profile-ground to DIN/ISO Class 6. Optimised tooth geometry matches Auburn Model 4 original specifications for validated service life.

Output Shaft Bearings

Heavy-series tapered roller bearing pair at the output shaft, factory pre-adjusted for the correct preload. Sized for the combined radial load from driven component weight and overhang, plus the axial load from belt tensioning and screw auger thrust. Bearing nut provides positive shaft retention.

Sealing System

Triple-lip HNBR radial seal at the output shaft exit — compatible with SAE 80W-90 gear oil and resistant to agricultural chemical splash, grain dust, and process material contact. IP67 wash-down variant available for food processing and agricultural applications requiring pressure washing.

Motor Mounting Face

CNC-machined to SAE A, B, or C flange accuracy per SAE J744. Motor pilot bore is H7 tolerance. SAE grade 8 motor mounting bolt holes. Initial oil change after first 50 operating hours is recommended to flush break-in wear particles — subsequent changes every 1,000 to 2,000 hours depending on operating conditions.

Parking Brake Option

Optional spring-applied, hydraulically or electrically released integral brake housed within the gearbox envelope. Located on the high-speed input stage for compact packaging. Critical for vertical shaft-down conveyor and mixer installations where backdrive prevention under power loss is a safety requirement.

Surface Treatment

Epoxy zinc phosphate primer (80 µm) plus two-component PU topcoat (80 µm). Salt spray resistance above 500 hours per ISO 9227. Chemical-resistant epoxy coating option for fertiliser, pesticide, and process chemical environments. RAL colour matching for OEM machine colour-coding.

Conveyor Drive — Belt, Chain, and Screw

The shaft output planetary gearbox for conveyors mounts to the conveyor head drum shaft housing, with the output shaft inserted into the drum shaft bore via keyway connection. Double-reduction ratios (13:1 to 20:1) match typical orbit motor speeds (300 to 600 RPM) to conveyor belt speeds of 0.5 to 3.0 m/s. Auburn Model 4 is cited as the most-ordered shaft output drive for this application — our unit provides the same performance at competitive lead times from stock.

Industrial Mixer and Agitator

The solid shaft gear reducer for industrial mixers connects directly to the mixer impeller shaft — either downward through the top of the tank (shaft-down, vertical mount) or via a right-angle coupling below the motor. High-torque double-reduction variants (20:1 to 33:1) provide the slow-speed, sustained torque required for viscous product mixing — concrete, mortar, feed rations, fertiliser blends, and industrial process chemicals.

Agricultural Auger and Grain Screw

Grain augers, seed cleaners, TMR feed mixer discharge screws, and fertiliser spreader drives use the Model 4 shaft output to transmit hydraulic motor power to the screw shaft. The compact coaxial design fits within the tight constraints of agricultural equipment chassis, and the fully reversible operation allows the auger to be run in reverse to clear blockages without any additional mechanism.

Material Handling and Elevators

Bucket elevators, chip conveyors, recyclable material sorting conveyors, and aggregate handling systems use the Model 4 shaft output drive mounted at the head drive station. The output shaft connects to the drive sprocket or drum shaft directly. High-cycle start-stop operation is handled by the planetary gear set's distributed load capacity and the ductile iron housing's vibration damping.

Packaging Machinery

Filling machines, capping lines, labelling equipment, and form-fill-seal machinery use compact planetary shaft output drives to translate electric motor speed to the precise low-speed output needed for controlled product metering and packaging. Single-reduction variants (3.75:1 to 5.8:1) provide the higher output speeds required by packaging line drives, while the electric motor interface enables VFD speed control.

Winch, Hoist, and Capstan Drive

Where a winch drum shaft protrudes from the drum end for gearbox mounting — common in small to medium industrial and agricultural winches — the shaft output configuration allows the drum shaft to be inserted directly into the output shaft bore. The optional parking brake provides load holding when hydraulic power is removed, preventing rope or chain runback under suspended load.

Complete Your Drive System: Model 4 Shaft Output Gearbox + PTO Shaft

For agricultural augers, TMR feed mixer drives, and tractor-powered conveyor systems, pairing our Model 4 Shaft Output Planetary Gearbox with a matched PTO Shaft creates a complete, dependable power transmission drivetrain from tractor PTO to the driven machinery shaft.

In tractor-powered grain augers, TMR feed mixers, silage cutters, and portable conveyor systems, a PTO shaft delivers rotational power from the tractor's power take-off to the input of the Model 4 shaft output planetary gearbox — which then reduces that speed to the precise low-speed, high-torque output needed to drive the auger screw, mixer impeller, or conveyor drum. The solid output shaft of the Model 4 then inserts directly into the driven component hub, completing the drivetrain from tractor PTO to driven machinery in a compact, reliable package.

Step 1: Define Max Output Torque

Determine peak torque at the output shaft in N·m, including start-up torque (typically 2 to 3 times running torque for conveyors and mixers). Apply service factor 1.5 to 2.5. Confirm below 3,390 N·m intermittent maximum.

Step 2: Calculate Gear Ratio

Gear ratio equals motor RPM divided by required output shaft RPM. For conveyors: output RPM equals belt speed in m/s divided by (pi times drum radius in metres) times 60. Select nearest standard ratio code.

Step 3: Specify Motor Interface

Confirm motor type (hydraulic orbit, axial-piston, or electric), SAE flange designation (A, B, or C), and shaft diameter or spline standard. For electric motors, specify IEC frame size for B5 adaptor plate.

Step 4: Specify Output Shaft

Confirm output shaft type (keyed cylindrical, SAE splined, DIN splined), shaft diameter, and keyway or spline specification. Advise required shaft length if different from standard. For OEM replacement, provide existing part number for exact match.

Step 5: Confirm Mounting and Options

Confirm mounting orientation (horizontal, vertical shaft-up/down). Specify whether parking brake is required. Advise operating environment (food grade, chemical wash-down, outdoor agricultural) for sealing and coating specification.