Industrial gearbox types—and what changes when you replace them

Gearbox “type” describes the power path and geometry, not interchangeability. Use this comparison to identify the architecture you are looking at and the dimensions or ratings that matter most before selecting another unit.

Inline helical

Layout: Input and output generally share or closely follow the same axis.
Why it is used: Efficient, common industrial architecture; broad torque and ratio coverage through multiple stages.
Replacement checks: Check shaft center height, foot/flange pattern, shaft diameter, ratio, service rating, and motor adapter.
Examples in this catalog: SEW R series, Lenze g500-H, WEG WG20 helical, Rossi coaxial families

Parallel-shaft helical

Layout: Input and output shafts are parallel but offset.
Why it is used: Compact in one dimension; common on conveyors and material-handling equipment.
Replacement checks: Output offset, hollow-bore/shaft style, torque-arm or flange arrangement, and output side are critical.
Examples in this catalog: SEW F series, Lenze g500-S, WEG WG20 parallel-shaft

Bevel-helical

Layout: Right-angle output using bevel gearing plus helical stages.
Why it is used: High-efficiency right-angle drive with substantial torque capability.
Replacement checks: Verify hand/output side, shaft or hollow bore, offset geometry, mounting position, ratio, and motor location.
Examples in this catalog: SEW K series, WEG WG20 helical-bevel, STOBER K/KL, FLENDER bevel-helical

Worm

Layout: Usually right-angle, using a worm and worm wheel.
Why it is used: Compact, quiet, high ratios in relatively few stages; widely used in lighter industrial machinery.
Replacement checks: Efficiency and thermal capacity vary with ratio/load. Check center distance, shaft orientation, output bore/shaft, lubricant, and duty.
Examples in this catalog: Dodge Tigear-2, Motovario NMRV/NMRVpower, Rossi A series

Hypoid

Layout: Right-angle gearing with offset axes and hypoid tooth geometry.
Why it is used: Compact right-angle arrangement with good efficiency and quiet operation.
Replacement checks: Do not substitute solely because it resembles a worm reducer. Check ratio, output geometry, center distances, mounting, and rated torque.
Examples in this catalog: Sumitomo HYPONIC

Cycloidal

Layout: Cycloidal disc reduction rather than conventional involute gear stages.
Why it is used: High reduction ratios and shock-load capability in compact industrial packages.
Replacement checks: Check exact frame, ratio, output shaft/flange, mounting, motor configuration, and allowable radial/thrust loads.
Examples in this catalog: Sumitomo Cyclo 6000

Planetary

Layout: Coaxial sun, planet, and ring-gear arrangement.
Why it is used: High torque density and compact coaxial packaging; used from precision servo to heavy industry.
Replacement checks: Verify output interface, backlash requirement, bearing loads, ratio, mounting, duty, and torsional stiffness where motion accuracy matters.
Examples in this catalog: Industrial planetary platforms and precision servo planetary gearboxes

Do not identify by appearance aloneField rule

A right-angle housing may contain worm, hypoid, bevel-helical, or other gearing. An inline unit may be helical, planetary, cycloidal, or a combination. The nameplate/model and manufacturer documentation are stronger evidence than visual similarity.

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