{"id":727,"date":"2026-06-03T00:51:56","date_gmt":"2026-06-03T00:51:56","guid":{"rendered":"https:\/\/planetary-gearboxes.com\/?p=727"},"modified":"2026-06-03T00:51:56","modified_gmt":"2026-06-03T00:51:56","slug":"square-flange-vs-round-flange-planetary-gearbox","status":"publish","type":"post","link":"https:\/\/planetary-gearboxes.com\/fr\/square-flange-vs-round-flange-planetary-gearbox\/","title":{"rendered":"R\u00e9ducteur plan\u00e9taire \u00e0 bride carr\u00e9e ou \u00e0 bride ronde"},"content":{"rendered":"
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La Cor\u00e9e toujours puissante<\/span>
\nMounting Interface Selection Guide<\/span><\/div>\n

Square Flange vs Round Flange Planetary Gearbox \u2014 EP-ZDF vs EP-ZDE Complete Selection Guide<\/h1>\n

EP-ZDE and EP-ZDF share every<\/em> performance specification. Identical gear stages, identical torque ratings, identical backlash, identical torsional stiffness. The only difference is the mounting interface \u2014 and that difference has engineering consequences for r\u00e9ducteur plan\u00e9taire de pr\u00e9cision<\/a> concentricity, mounting structure cost, installation time, and field replaceability that determine which is correct for any specific application. This guide provides the analysis that most product datasheets omit entirely.<\/p>\n

Get Mounting Interface Specification Support \u2192<\/a><\/p>\n<\/div>\n<\/div>\n<\/section>\n

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What Is Identical, What Differs \u2014 The Complete Specification Comparison<\/h2>\n

The most important fact about the EP-ZDE versus EP-ZDF selection is this: the two series differ in exactly one respect. Every precision engineering parameter \u2014 gear geometry, torque capacity, efficiency, backlash, torsional stiffness, bearing life, lubrication, temperature range, IP rating \u2014 is shared between the two series for any given frame size and ratio combination. Selecting ZDF over ZDE, or vice versa, has no effect whatsoever on the gearbox performance in service. It affects only the ease, accuracy, and cost of mounting.<\/p>\n

\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Specification Parameter<\/th>\nEP-ZDE
\nRound flange<\/span><\/th>\n		EP-ZDF
\nSquare flange<\/span><\/th>\n		Impact on Selection<\/th>\n<\/tr>\n<\/thead>\n
Gear stages and ratios<\/td>\nIdentical \u2705<\/td>\nIdentical \u2705<\/td>\nNone<\/td>\n<\/tr>\n
Couple de sortie nominal<\/td>\nIdentical \u2705<\/td>\nIdentical \u2705<\/td>\nNone<\/td>\n<\/tr>\n
Backlash specification<\/td>\n<8 arcmin \u2705<\/td>\n<8 arcmin \u2705<\/td>\nNone<\/td>\n<\/tr>\n
Rigidit\u00e9 en torsion Ct<\/td>\nIdentical \u2705<\/td>\nIdentical \u2705<\/td>\nNone<\/td>\n<\/tr>\n
Efficiency per stage<\/td>\n96%\/94%\/90% \u2705<\/td>\n96%\/94%\/90% \u2705<\/td>\nNone<\/td>\n<\/tr>\n
Bearing life (L10)<\/td>\n20,000h \u2705<\/td>\n20,000h \u2705<\/td>\nNone<\/td>\n<\/tr>\n
IP rating<\/td>\nIP54 \u2705<\/td>\nIP54 \u2705<\/td>\nNone<\/td>\n<\/tr>\n
Temperature range<\/td>\n\u221225 to +90\u00b0C \u2705<\/td>\n\u221225 to +90\u00b0C \u2705<\/td>\nNone<\/td>\n<\/tr>\n
Output shaft dimensions<\/td>\nIdentical \u2705<\/td>\nIdentical \u2705<\/td>\nNone<\/td>\n<\/tr>\n
Housing mounting interface<\/td>\nRound: pilot \u00d8 + bolt circle<\/td>\nSquare: 4-bolt flat plate<\/td>\n\u2605 THE ONLY DIFFERENCE<\/td>\n<\/tr>\n
Concentricity reference<\/td>\nPilot bore \u2192 <0.01mm TIR<\/td>\nShaft alignment only<\/td>\n\u2605 Affects mounting precision<\/td>\n<\/tr>\n
Required mounting structure<\/td>\nCNC-bored precision plate<\/td>\nFlat plate, laser-cut holes<\/td>\n\u2605 Affects manufacturing cost<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n
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The correct selection principle:<\/strong> Do not choose ZDF to save money \u2014 the unit price difference is less than \u00b15% and should not drive the decision. Do not choose ZDE because it “sounds more precise” \u2014 the gear internals are identical. Choose based solely on whether your mounting structure provides (or requires) the pilot bore centering reference that round flange delivers, or whether you need the bolt-on simplicity of square flange for a non-precision mounting surface.<\/p>\n<\/div>\n<\/section>\n

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\"EP-ZDE<\/p>\n
The EP-ZDE series round-flange precision planetary gearbox features a precision pilot diameter (\u03a650h6 to \u03a6130h6 by frame size) that provides concentricity reference for applications requiring housing-to-load-axis alignment \u2014 CNC rotary axes, robot joints, direct-coupled ballscrew drives, and precision spindle mounts. All gear internals, torque ratings, and performance specifications are identical to the EP-ZDF square-flange series. View EP-ZDE planetary gearbox specifications \u2192<\/a><\/div>\n<\/div>\n

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Round Flange (EP-ZDE) \u2014 How the Pilot Bore Provides Concentricity<\/h2>\n

The defining feature of the EP-ZDE round flange is the precision pilot diameter \u2014 a short cylindrical register on the gearbox housing face that locates into a matching precision bore in the mounting plate. This pilot-to-bore interface is the mechanical reference that centres the gearbox output shaft relative to the mounting structure with an accuracy better than 0.02mm TIR, achievable without any alignment instruments after installation.<\/p>\n

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What the pilot bore provides<\/div>\n