Model 4 Flanged Output Drives Planetary Gearbox

Zero Overhang Load

With a shaft output, the driven component (sprocket, gear, drum) hangs off the end of the shaft, creating a bending moment on the output bearing. A flanged output bolts directly to the driven component's mating flange, transferring load through a large-diameter bolt circle rather than a single shaft — eliminating overhang-induced bearing loads entirely.

Maximum Torsional Stiffness

A large-diameter output flange has inherently higher torsional stiffness than a small-diameter output shaft of equivalent material. For applications requiring angular positioning accuracy — rotary tables, indexing drives, and slewing systems — this stiffness translates directly into improved positional repeatability and reduced compliance error under load.

Compact Axial Length

Because the flanged output eliminates the projecting shaft and any associated coupling, the overall axial envelope of the drive-plus-driven-component assembly is significantly shorter than an equivalent shaft-output arrangement. This is critical in space-constrained machine tool and automation applications where every millimetre of axial length affects machine footprint.

Versatile Attachment

The standardised bolt circle of a flanged output allows it to mate with pulleys, gears, rotary table bearings, winch drum flanges, chain sprockets, and many other transmission components — all without any custom coupling hardware. A single gearbox model can drive many different machinery types simply by matching the bolt circle to the driven component.

Motor Input

A hydraulic motor (SAE flange) or electric motor (IEC B5) drives the planetary sun gear at high speed via a splined or keyed input shaft on the fixed housing face.

Planetary Reduction

The sun gear drives three or more planet gears meshing with a fixed ring gear. The planet carrier rotates at reduced speed with multiplied torque — one or two stages delivering up to 33.79:1 ratio.

Flanged Output Face

The final planet carrier drives the output flange — a precision-machined face with a standardised bolt circle that bolts directly to the driven component (rotary table, winch drum, sprocket hub, etc.).

Load Distribution

Loads from the driven machinery are transferred through the large-diameter bolt circle into the output bearing pair — distributing forces over a wide area and eliminating shaft bending moments that reduce bearing life.

Optional Parking Brake

An optional integral B4 Series spring-applied brake acts on the input stage, locking the output flange in position when hydraulic or electric release pressure is removed — ideal for rotary table positioning hold and winch load holding.

Direct Auburn Model 4 Replacement

Every dimension is verified against Auburn Gear Model 4 FD drawings — output flange bolt circles (4.187" and 5.750" B.C.), SAE motor flange, oil port locations, and overall axial length. A true bolt-on replacement with no machine modification required.

Zero Overhang — Maximum Moment Rigidity

The flanged output transfers all driven-component loads through the large-diameter bolt circle directly into the output bearing pair, eliminating shaft bending moments. This results in superior moment stiffness and dramatically extended bearing life versus equivalent shaft-output drives.

Ideal for Rotary Table Applications

The flanged output planetary gearbox for rotary tables provides the output stiffness, precise concentricity, and compact axial length that rotary table designers require. The flange bolts directly to the table bearing inner ring, eliminating couplings and reducing positional error from coupling compliance.

Wide Ratio Range in Compact Envelope

Single-reduction (3.75:1 to 5.8:1) and double-reduction (13.06:1 to 33.79:1) variants share the same housing diameter, allowing ratio changes without machine redesign. A single mounting interface covers from fast conveyor drives to slow heavy-torque rotary table positioning.

Integral B4 Parking Brake Available

Compatible with the Auburn Gear B4 Series integral spring-applied hydraulic-release parking brake, housed entirely within the gearbox envelope. Essential for rotary table load holding in machining and inspection applications, and for winch load holding on powered-off machines.

Hollow Centre Bore Option

An optional hollow centre bore passing through the entire gearbox allows cables, hydraulic lines, pneumatic tubes, or sensors to be routed through the axis of rotation — a critical feature for rotary table, robot joint, and slewing drive applications where through-bore feed is required.

Dual Motor Compatibility

Available with SAE A, B, or C hydraulic motor flanges for hydrostatic drive systems, or IEC B5 electric motor adaptor plates for electro-mechanical installations. The same output flange and gear set serve both drive types — simplifying inventory management for OEM users.

3,390 N·m at 96–98% Efficiency

Maximum intermittent output torque of 3,390 N·m (30,000 lb-in) at 96 to 98 percent transmission efficiency. The planetary architecture distributes load across three or more planet gears simultaneously, achieving this torque in a housing diameter of approximately 220 to 260 mm — where equivalent worm gearboxes would be two to three times larger.

Output Flange

CNC-machined to achieve 0.02 mm face runout TIR and 0.015 mm pilot bore concentricity. Bolt holes are drilled and tapped to H7 tolerance for tight fastener engagement. Two standard bolt circles (4.187" and 5.750" B.C.) cover the majority of application interfaces.

Housing and Fixed Ring Carrier

GGG-50 ductile iron housing provides impact resistance and vibration damping. The fixed (stationary) housing carries the ring gear and motor mounting face. The rotating output carrier is the flanged output component, supported by the main bearing pair.

Planetary Gear Set

All gears manufactured from 18CrNiMo7-6 alloy steel, vacuum carburized, case-hardened to 58-62 HRC, then profile-ground to DIN/ISO Class 6 accuracy. Heat-treated ring gear minimises tooth wear and backlash growth over service life.

Output Bearing System

Matched tapered roller bearing pairs support the rotating output flange carrier, pre-adjusted at factory to provide the correct running preload for the application torque class. Factory preload verification ensures consistent bearing life and flange runout across production batches.

Integral Parking Brake (B4 Series)

Optional B4 Series spring-applied, hydraulically or electrically released brake is located on the input high-speed stage, enclosed within the housing with no external protrusion. Multiple torque ratings available. Hydraulic release port is SAE straight-thread O-ring boss standard.

Sealing and Lubrication

HNBR radial lip seals at the output flange shaft interface. Oil fill, level, and drain ports machined into the fixed housing per Auburn Gear standard locations. Shipped without oil — fill with SAE 80W-90 GL-5 gear oil to the sight-glass level before start-up.

Motor Mounting Face

Motor input face is CNC-machined to SAE A, B, or C flange accuracy. Motor pilot bore is H7 tolerance for radial centring. All motor mounting bolt holes are drilled and tapped per SAE J744. IEC B5 adaptor plates are available for standard induction, servo, or explosion-proof electric motors.

Surface Treatment

External surfaces: epoxy zinc phosphate primer (80 µm) plus two-component PU topcoat (80 µm). Salt spray resistance above 500 hours per ISO 9227. All machined interface faces left bare metal with protective oil coating — no paint on sealing and mating surfaces.

Rotary Table Drive

The flanged output planetary gearbox for rotary tables bolts directly to the inner ring of the table's slewing bearing, eliminating couplings and concentricity errors that degrade angular positioning accuracy. In CNC machining centres, inspection tables, and assembly turntables, the gearbox's high torsional stiffness and integral brake ensure repeatable positioning. The hollow centre bore option allows wiring and coolant lines to pass through the table axis.

Winch and Hoist Drum Drive

The flanged output mounts directly to the winch drum end flange, creating a rigid torque path without couplings or key-and-keyway interfaces that can develop fretting corrosion under reversing loads. The optional parking brake provides automatic load holding when hydraulic pressure is removed — critical for suspended load safety in industrial and construction hoists.

Conveyor and Material Handling

In underground mining conveyors, aggregate handling systems, and port material handling equipment, the flanged output gearbox mounts to the conveyor head drum shaft flange, providing high-torque low-speed drive with minimal footprint. The wide ratio range (3.75:1 to 33.79:1) allows the same gearbox to match a wide range of belt speeds and motor types.

Slewing and Swing Drive

Crane and excavator slewing systems, rotating radar and antenna platforms, and offshore derrick slewers use flanged output planetary gearboxes to drive the pinion shaft that meshes with the slewing ring. The high torsional stiffness of the flanged output minimises torsional windup that would cause positioning jerk and gear tooth impact in dynamic slewing applications.

Robotics and Automation

Robot joint drives, automatic welding positioners, and automated guided vehicle steer drives use flanged output planetary gearboxes where precise angular control, compact installation, and high-cycle durability are required. The hollow centre bore enables wiring harness routing through the joint axis, enabling clean robot arm cable management.

Packaging and Processing Machinery

Filling machines, labelling lines, rotary indexers, and food processing turntables demand compact, hygienic, and precise drive units. The flanged output gearbox provides direct coupling to turntable platens and indexing discs with no external coupling hardware to trap product debris. Stainless steel fasteners and FDA-approved seal options are available for food-contact applications.

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

For agricultural and field machinery applications where a tractor PTO is the power source, pairing our Model 4 Flanged Output Planetary Gearbox with a matched PTO Shaft creates a complete drivetrain from tractor PTO output to driven machinery flange.

In tractor-powered rotary equipment, post-hole diggers, mixer drives, and self-propelled machinery where the engine output is remote from the flanged drive unit, a PTO shaft connects the tractor PTO to the input of the Model 4 flanged gearbox. This delivers the high input speed of the tractor PTO to the gearbox, which reduces it to the precise low-speed, high-torque output required by the driven machinery — all through the rigid flanged output connection.

Step 1: Define Max Output Torque

Determine the maximum torque required at the output flange in N·m, including peak and shock load conditions. Apply a service factor of 1.5 to 2.5 for shock loading and duty class. Confirm this is below 3,390 N·m intermittent maximum.

Step 2: Calculate Gear Ratio

Required ratio equals motor max RPM divided by required output RPM. Confirm motor rated torque multiplied by gear ratio exceeds required output torque by the service factor. Select nearest standard ratio code (04, 06, 13, 16, 20, 22, 25, 28, 33).

Step 3: Specify Motor Interface

Confirm motor type (hydraulic or electric), flange standard (SAE A, B, C or IEC B5), and shaft diameter. For servo applications, specify encoder interface requirement and required backlash class.

Step 4: Specify Output Flange

Confirm output flange bolt circle diameter (4.187" or 5.750" B.C. standard, or custom), number of bolt holes, pilot diameter, and whether a hollow centre bore is required. Specify through-bore diameter if applicable.

Step 5: Confirm Options

Confirm whether integral parking brake is required (specify hydraulic or electric release, brake release pressure, required holding torque). Advise operating environment for sealing and coating specification. Note quantity for volume pricing.