{"id":1902,"date":"2026-07-21T06:49:50","date_gmt":"2026-07-21T06:49:50","guid":{"rendered":"https:\/\/gearrack.top\/?p=1902"},"modified":"2026-07-21T06:49:50","modified_gmt":"2026-07-21T06:49:50","slug":"helical-gears-for-compressors","status":"publish","type":"post","link":"https:\/\/gearrack.top\/fr\/helical-gears-for-compressors\/","title":{"rendered":"Helical Gears for Compressors"},"content":{"rendered":"
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GEAR APPLICATION GUIDE \u00b7 HELICAL GEAR \u00b7 H05<\/span><\/p>\n

Helical Gears for Compressors:
\nCentrifugal, Screw and Reciprocating Compressor Gear Drives<\/span><\/h1>\n

Compressor gear drives operate at the highest pitch line velocities of any commercial helical gear application \u2014 centrifugal compressor integral gearboxes run bull gear pinions at PLV above 150 m\/s, requiring gear quality classes and surface finish levels that exceed even wind turbine gearbox requirements. Screw compressor timing gears must synchronise male and female rotors to micron-level tolerance to maintain the rotor clearance that separates oil-injected from oil-free compressor performance. This guide covers helical gear specification for centrifugal turbocompressors, screw compressors, and reciprocating compressor crosshead gearboxes.<\/p>\n

18CrNiMo7-6 \u00b7 42CrMo4 \u00b7 DIN 3\u20135<\/span>
\nPLV up to 200 m\/s \u00b7 API 613 \u00b7 AGMA 421<\/span>
\nCentrifugal \u00b7 Screw \u00b7 Reciprocating \u00b7 API<\/span><\/div>\n<\/div>\n<\/div>\n
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MAX PLV<\/p>\n

200 m\/s<\/p>\n

Pitch line velocity of centrifugal compressor integral gearbox bull gear pinions \u2014 the highest PLV of any commercial gear application. DIN 3 quality mandatory; superfinishing to Ra <0.05 \u03bcm required above 100 m\/s PLV to avoid dynamic instability<\/p>\n<\/div>\n

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DESIGN STANDARD<\/p>\n

API 613<\/p>\n

Special Purpose Gear Units for Petroleum, Chemical and Gas Industry Service \u2014 the dominant specification for compressor helical gears in the oil & gas and petrochemical industries. Sets requirements for material, quality class, inspection, and documentation beyond standard ISO 6336<\/p>\n<\/div>\n

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HELIX ANGLE<\/p>\n

15\u00b0 \u2013 35\u00b0<\/p>\n

Compressor helical gear helix angle range. Screw compressor timing gears: 15\u00b0\u201320\u00b0. Centrifugal compressor bull gear: 20\u00b0\u201330\u00b0. Double-helical (herringbone) compressor gears: 30\u00b0\u201335\u00b0 per helix, axial thrust cancelled<\/p>\n<\/div>\n

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QUALITY CLASS<\/p>\n

DIN 3 \u2013 5<\/p>\n

Compressor helical gear quality class range. Centrifugal compressor integral gear: DIN 3. Screw compressor timing gear: DIN 4. Reciprocating compressor crosshead gear: DIN 5. All compressor gears ground; superfinishing above PLV 80 m\/s<\/p>\n<\/div>\n<\/div>\n

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Compressor Gear Drive Design \u2014 Applications and Requirements<\/h2>\n

Compressors use helical gears in three fundamentally different functional roles: the speed-increasing bull gear pinion of centrifugal compressors (which accelerates the motor shaft speed to the impeller operating speed); the synchronisation timing gears of twin-screw compressors (which maintain the angular phase relationship between male and female rotors); and the power balancing and crosshead drive gears of some large reciprocating compressors (which synchronise cylinders in multi-cylinder balanced opposed configurations). Each role places different primary demands on the helical gear \u2014 PLV and noise minimisation for centrifugal compressor gears, rotor clearance maintenance for screw compressor timing gears, and shock tolerance for reciprocating compressor drives.<\/p>\n

\"Helical<\/p>\n

Korea Ever-Power’s helical gears for compressors<\/a> are manufactured in 18CrNiMo7-6 case carburized (standard for all compressor helical gear applications requiring DIN 3\u20134 quality), and in 42CrMo4 through-hardened (for medium-duty reciprocating compressor applications at DIN 5\u20136). Centrifugal compressor bull gear pinions are manufactured with superfinished tooth flanks (Ra <0.05 \u03bcm) and ground tooth profiles to the limits of DIN 3 quality class \u2014 representing the extreme upper end of Korea Ever-Power’s manufacturing capability for helical gears. All compressor helical gears for oil & gas and petrochemical service are supplied to API 613 documentation requirements including material certification, heat treatment records, and non-destructive examination (magnetic particle or dye penetrant inspection) reports.<\/p>\n

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TYPE 01<\/p>\n

CENTRIFUGAL
\nTURBOCOMPRESSOR<\/p>\n<\/div>\n

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Helical gear specification:<\/strong> M2\u2013M8, 18CrNiMo7-6 case carburized, DIN 3 mandatory, PLV 50\u2013200 m\/s, superfinished Ra <0.05 \u03bcm, single-helical or double-helical (herringbone). The centrifugal compressor (turbocompressor) integral gearbox steps up the motor speed (typically 1,450\u20133,000 RPM) to the impeller shaft speed required for the operating pressure ratio \u2014 for a process air compressor with 8 bar discharge pressure, this may require 12,000\u201325,000 RPM, demanding a speed ratio of 8:1\u201317:1. The bull gear pinion (the high-speed output shaft) runs at pitch line velocities of 80\u2013200 m\/s \u2014 a regime where aerodynamic losses from the gear teeth windage become significant (typically 20\u201340 kW at 150 m\/s PLV), where oil supply must be carefully directed to avoid oil aeration at the tooth mesh, and where dynamic instability from tooth-to-tooth spacing error can cause sub-synchronous vibration of the pinion shaft in its journal bearings. DIN 3 ground quality is mandatory \u2014 no other quality class can reliably prevent dynamic problems at these speeds.<\/p>\n<\/div>\n<\/div>\n

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TYPE 02<\/p>\n

TWIN-SCREW
\nCOMPRESSOR<\/p>\n<\/div>\n

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Helical gear specification:<\/strong> M3\u2013M8, 18CrNiMo7-6 or 42CrMo4, DIN 4\u20135, timing gear pair on the male and female rotor shafts with angular phase accuracy <0.5 arcmin. The twin-screw compressor (oil-injected and oil-free) uses a pair of helical timing gears on the rotor shafts to maintain the angular relationship between the male rotor (with 4 or 5 lobes) and the female rotor (with 6 or 7 flutes). In oil-injected compressors, the rotor clearance (0.05\u20130.15 mm) is maintained partly by the oil film and partly by the timing gear angular accuracy. In oil-free compressors (which cannot use oil for clearance maintenance), the timing gear angular accuracy is the sole mechanism maintaining rotor clearance \u2014 any backlash or transmission error in the timing gear pair allows the rotors to touch, destroying both rotors instantly. Oil-free screw compressor timing gears are specified to DIN 4 or better with zero-backlash anti-backlash gear pairs in some designs.<\/p>\n<\/div>\n<\/div>\n

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TYPE 03<\/p>\n

RECIPROCATING
\nCOMPRESSOR<\/p>\n<\/div>\n

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Helical gear specification:<\/strong> M8\u2013M20, 42CrMo4 through-hardened or 20CrMnTi case carburized, DIN 5\u20136, wide face width for high torque, service factor 1.5\u20132.5 for gas surge and pulsation loads. Large reciprocating compressors (process gas compressors in oil refineries and LNG plants) use helical gears in the balanced-opposed cylinder configuration to synchronise multiple crankshafts, reducing primary and secondary vibration forces. The helical gear in a reciprocating compressor experiences highly variable torque input from the gas piston forces \u2014 every cylinder stroke produces a torque pulse at the crankshaft, and if multiple cylinders are out of phase the gear experiences complex cyclic loading at the crank frequency. Helical gears with high contact ratio (achieved through helix angle) smooth the individual cylinder torque pulses and reduce vibration transmission to the compressor foundation. Korea Ever-Power supplies replacement helical gear sets for major reciprocating compressor brands including Ariel, Dresser-Rand, Nuovo Pignone, and MAN Energy Solutions.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/section>\n

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Frequently Asked Questions<\/h2>\n
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Q 01<\/span><\/p>\n

What causes high vibration at the gear mesh frequency in a centrifugal compressor integral gearbox, and how is it resolved?<\/p>\n<\/div>\n

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High gear mesh frequency vibration (GMF vibration) in a centrifugal compressor integral gearbox has three primary causes: (1) Tooth profile error above DIN 3 limit:<\/strong> the most common cause of excessive GMF vibration \u2014 tooth-to-tooth spacing error generates a dynamic force increment at the mesh frequency that excites the pinion lateral vibration mode. Confirm by measuring the 1X and GMF components on the pinion shaft vibration spectrum \u2014 if GMF is the dominant frequency and exceeds the API 670 limit of 25.4 \u03bcm p-p, profile error is the prime suspect. Remedy: replace the bull gear and pinion with DIN 3 quality superfinished gears. (2) Tooth contact pattern misalignment from housing thermal distortion:<\/strong> at operating temperature the gearbox housing expands thermally, shifting the shaft centreline positions and altering the tooth contact pattern from the cold-assembly condition. If GMF vibration occurs only at operating temperature (not during cold run-up), thermal misalignment is the cause. Remedy: re-measure the thermal growth vector of the housing and add pre-alignment offset at assembly. (3) Oil aeration in the tooth mesh zone:<\/strong> at PLV above 100 m\/s, excessive oil directed at the mesh zone causes aeration and hydraulic churning that generates both vibration and power loss. Reduce oil injection quantity at the mesh and redirect to the outmesh side only. Korea Ever-Power can supply replacement DIN 3 superfinished bull gear pinions for most centrifugal compressor gearboxes within 35\u201350 days \u2014 contact with the compressor model and gear geometry for availability assessment.<\/p>\n<\/div>\n<\/div>\n

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Q 02<\/span><\/p>\n

What API standard governs compressor helical gear design and what does compliance require from a gear manufacturer?<\/p>\n<\/div>\n

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API 613 (Special Purpose Gear Units for Petroleum, Chemical and Gas Industry Service) is the primary standard for process industry compressor helical gears. API 613 compliance requires from the gear manufacturer: (1) Mat\u00e9riel:<\/strong> through-hardened alloy steel or carburized alloy steel per API 613 Table 3 (broadly equivalent to 42CrMo4 or 18CrNiMo7-6 respectively), with mill certification of chemical composition and mechanical properties to be submitted with the gear. (2) Quality class:<\/strong> API 613 Section 2.9 requires the gear accuracy to meet AGMA Quality Class 13 or better (approximately equivalent to DIN 4) for all special purpose gear sets. (3) Inspection:<\/strong> 100% magnetic particle or dye penetrant inspection of all tooth flanks and roots after finish grinding; hardness check on minimum 3 tooth flanks per gear; surface finish Ra measurement on minimum 3 tooth flanks per gear. (4) Documentation:<\/strong> Mechanical run test at rated speed and power with vibration measurement per API 613; traceability documentation for all materials; heat treatment records with temperature-time curves; dimensional inspection report in customer-specified format. Korea Ever-Power provides all API 613 documentation as standard for compressor helical gear orders destined for oil & gas or petrochemical plant service.<\/p>\n<\/div>\n<\/div>\n

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Q 03<\/span><\/p>\n

My screw compressor is showing rotor contact marks (seizure lines on the rotor lobes). Could the timing gear be the cause, and how should I specify the replacement?<\/p>\n<\/div>\n

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Rotor contact in an oil-free screw compressor is frequently caused by timing gear backlash increase from tooth wear \u2014 the mechanical clearance in the timing gear allows the male rotor to advance angularly ahead of the female rotor during the compression stroke torque peak, reducing the inter-rotor clearance on the high-pressure side of the mesh until contact occurs. Diagnosis: measure timing gear backlash by locking the male rotor and rotating the female rotor shaft by hand at the timing gear \u2014 backlash above 0.03 mm for an oil-free screw compressor timing gear indicates replacement is required. In an oil-injected screw compressor, timing gear backlash limit is more relaxed (0.05\u20130.08 mm acceptable) because the oil film also maintains rotor separation. Replacement timing gear specification for an oil-free screw compressor: match the original module, tooth count, and helix angle exactly (any change alters the rotor phase relationship); specify 18CrNiMo7-6 carburized if the original was carburized (do not downgrade to 42CrMo4 through-hardened for oil-free service); specify DIN 4 quality class; measure and certify the backlash of the replacement pair at the specified centre distance before installation. Korea Ever-Power can supply replacement screw compressor timing gear pairs for all major brands \u2014 contact with the compressor model, rotor profile generation, and motor power for timing gear availability and lead time.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/section>\n

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Explore Korea Ever-Power Gear Categories<\/h2>\n

Seven precision gear product lines for compressor, industrial, energy and specialist applications worldwide.<\/p>\n<\/div>\n

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\"spur<\/p>\n
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Spur Gears<\/a><\/p>\n

M1\u2013M20 \u00b7 C45, 20CrMnTi, stainless<\/p>\n<\/div>\n<\/div>\n

\"helical<\/p>\n
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Helical Gears<\/a><\/p>\n

DIN 3\u20135 \u00b7 compressor \u00b7 API 613<\/p>\n<\/div>\n<\/div>\n

\"bevel<\/p>\n
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Engrenages coniques<\/a><\/p>\n

Right-angle \u00b7 compressor aux drive<\/p>\n<\/div>\n<\/div>\n

\"worm<\/p>\n
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Worm Gears<\/a><\/p>\n

High ratio \u00b7 valve \u00b7 actuator \u00b7 hoist<\/p>\n<\/div>\n<\/div>\n

\"ring<\/p>\n
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Ring Gears<\/a><\/p>\n

Internal \u00b7 planetary \u00b7 high torque<\/p>\n<\/div>\n<\/div>\n

\"planetary<\/p>\n
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Planetary Gears<\/a><\/p>\n

Compact \u00b7 high torque density \u00b7 servo<\/p>\n<\/div>\n<\/div>\n

\"plastic<\/p>\n
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Plastic Gears<\/a><\/p>\n

POM \u00b7 PEEK \u00b7 instrument \u00b7 light duty<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/section>\n

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GET A QUOTATION \u00b7 KOREA EVER-POWER<\/p>\n

Need Helical Gears for Compressors?<\/h2>\n

Korea Ever-Power manufactures 18CrNiMo7-6 and 42CrMo4 helical gears for all compressor applications \u2014 centrifugal turbocompressor DIN 3 bull gear pinions (superfinished Ra <0.05 \u03bcm), screw compressor timing gears DIN 4, reciprocating compressor crosshead gears DIN 5\u20136. API 613 documentation package standard for oil & gas service. Replacement supply for Ariel, Dresser-Rand, Atlas Copco, Ingersoll Rand and all major compressor brands. ISO 9001:2015 certified.<\/p>\n

Request a Quotation \u2192<\/a><\/p>\n<\/div>\n

\u00c9diteur : Cxm<\/em><\/p>\n<\/div>\n<\/div>","protected":false},"excerpt":{"rendered":"

GEAR APPLICATION GUIDE \u00b7 HELICAL GEAR \u00b7 H05 Helical Gears for Compressors: Centrifugal, Screw and Reciprocating Compressor Gear Drives Compressor gear drives operate at the highest pitch line velocities of any commercial helical gear application \u2014 centrifugal compressor integral gearboxes run bull gear pinions at PLV above 150 m\/s, requiring gear quality classes and surface […]<\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":"","footnotes":""},"categories":[4566],"tags":[],"class_list":["post-1902","post","type-post","status-publish","format-standard","hentry","category-application-of-gears"],"_links":{"self":[{"href":"https:\/\/gearrack.top\/fr\/wp-json\/wp\/v2\/posts\/1902","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/gearrack.top\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/gearrack.top\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/gearrack.top\/fr\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/gearrack.top\/fr\/wp-json\/wp\/v2\/comments?post=1902"}],"version-history":[{"count":3,"href":"https:\/\/gearrack.top\/fr\/wp-json\/wp\/v2\/posts\/1902\/revisions"}],"predecessor-version":[{"id":1907,"href":"https:\/\/gearrack.top\/fr\/wp-json\/wp\/v2\/posts\/1902\/revisions\/1907"}],"wp:attachment":[{"href":"https:\/\/gearrack.top\/fr\/wp-json\/wp\/v2\/media?parent=1902"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/gearrack.top\/fr\/wp-json\/wp\/v2\/categories?post=1902"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/gearrack.top\/fr\/wp-json\/wp\/v2\/tags?post=1902"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}