{"id":1138,"date":"2026-04-24T02:11:41","date_gmt":"2026-04-24T02:11:41","guid":{"rendered":"https:\/\/worm-and-worm-wheel.com\/?post_type=product&p=1138"},"modified":"2026-04-24T02:11:42","modified_gmt":"2026-04-24T02:11:42","slug":"cylindrical-worm-wheel-sets-line-contact-worm-gearing","status":"publish","type":"product","link":"https:\/\/worm-and-worm-wheel.com\/da\/vare\/cylindrical-worm-wheel-sets-line-contact-worm-gearing\/","title":{"rendered":"Cylindrical Worm Wheel Sets | Line-Contact Worm Gearing"},"content":{"rendered":"
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Cylindrical Worm Wheel \u2014 Product Overview<\/h2>\n

A cylindrical ormehjul<\/strong> is a wheel whose teeth have been milled by a cutter ground to the same basic geometry as the mating shaft. This production method is what distinguishes the two major families inside the cylindrical worm family: the “worm and helical gear” pair, where a small-tooth helical pinion meshes at a crossed-shaft angle and contacts the wheel at a single point; and the “worm and worm wheel” pair, where the teeth are cut with the same mill as the shaft thread, producing line contact along the engaged tooth flank. Line contact is why the second arrangement carries significantly higher tooth force before surface fatigue becomes the limit.<\/p>\n

\"Cylindrical<\/p>\n

Ever-Power supplies both arrangements, but around 90 % of Korean industrial orders specify the true orme-og-ormehjul<\/a> pair because the extra load rating usually outweighs the modest cost difference. The product ships as a matched set \u2014 shaft plus wheel, cut from the same tool setup so the tooth profiles sit in perfect conjugate contact from the first revolution. Typical applications include conveyor drives, packaging-line indexers, solar tracker gearboxes, and parking-system lifts.<\/p>\n<\/section>\n

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Technical Specifications<\/h2>\n

The specification envelope below covers the catalogue geometry. Module, centre distance and tooth count are the parameters most often customised from the base catalogue \u2014 send a stamped drawing or the mating wheel for measurement, and the engineering desk quotes against it within two working days.<\/p>\n

\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Parameter<\/th>\nSpecifikation<\/th>\n<\/tr>\n<\/thead>\n
Arrangement Type<\/strong><\/td>\nCylindrical worm-and-worm-wheel (line contact) or worm-and-helical-gear (point contact)<\/td>\n<\/tr>\n
Module Range<\/strong><\/td>\nM1 \u2013 M12 (typical range)<\/td>\n<\/tr>\n
Wheel Material<\/strong><\/td>\nAluminium-iron bronze (primary) \/ tin bronze \/ ductile cast iron (low-speed only)<\/td>\n<\/tr>\n
Worm Material<\/strong><\/td>\nC45 steel \/ 20CrMnTi case-hardened alloy \/ stainless steel<\/td>\n<\/tr>\n
Worm Peripheral Speed<\/strong><\/td>\nUp to 10 m\/s (below this, standard oil bath is sufficient)<\/td>\n<\/tr>\n
Precision Grade<\/strong><\/td>\nDIN 6 \/ DIN 7 \/ DIN 8 \/ DIN 9<\/td>\n<\/tr>\n
Teeth Treatment<\/strong><\/td>\nHobbed, hardened, milled or ground<\/td>\n<\/tr>\n
Contact Geometry<\/strong><\/td>\nLine contact on worm-mill-cut wheels (preferred)<\/td>\n<\/tr>\n
Sm\u00f8ring<\/strong><\/td>\nOil bath up to 10 m\/s; splash ring or forced feed above<\/td>\n<\/tr>\n
Typical Ratio Range<\/strong><\/td>\n10:1 \u2013 100:1 in a single stage<\/td>\n<\/tr>\n
Lead Time<\/strong><\/td>\n20 days for sample; 25 days for bulk<\/td>\n<\/tr>\n
Standard Compliance<\/strong><\/td>\nISO 1122, DIN 3974, JIS B 1723 (typical range)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

Values noted “typical range” reflect the standard catalogue envelope; non-standard modules, speeds or ratios are supplied to customer drawing after a short engineering review.<\/p>\n<\/section>\n

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How the Cylindrical Worm Drive Transmits Power<\/h2>\n

The cylindrical arrangement works because the worm thread and the wheel teeth have been cut from the same basic geometry. When the shaft rotates, its thread flank slides against the wheel tooth flank along a contact line that sweeps across the tooth face once per revolution. The continuous sliding is why these drives need thicker, higher-pressure oil than gear drives and why efficiency sits lower \u2014 energy lost to sliding friction shows up as heat in the oil sump.<\/p>\n

Two production choices decide the mesh quality. The first is whether the wheel is milled with a true dedicated mill (the preferred method, giving line contact) or with a standard helical hob (cheaper, but producing only point contact). The second is whether the shaft thread is ground after heat treatment to remove distortion \u2014 a step that becomes mandatory once the specification calls for DIN 7 or tighter. On high-speed drives where the shaft peripheral velocity exceeds 10 m\/s, oil-bath lubrication starts to fail because the thread cannot pick up enough oil from the sump; at that point the wheel moves above the shaft (so-called overhead arrangement) and a splash ring is added to deliver oil to the bearings. This single change buys an extra 3 \u2013 5 m\/s of usable peripheral speed.<\/p>\n

\"worm<\/p>\n<\/section>\n

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Bronze Grades and Cast Iron \u2014 Wheel Material Matrix<\/h2>\n

Material choice on the wheel side drives almost every long-term characteristic of the drive: wear rate, efficiency, temperature stability, and unit cost. The table below summarises the three grades we stock, with the honest trade-offs for each.<\/p>\n

\n\n\n\n\n\n\n\n
Wheel Material<\/th>\nAnti-Galling<\/th>\nStrength<\/th>\nKoste<\/th>\nBest Fit<\/th>\n<\/tr>\n<\/thead>\n
Tin bronze (CuSn10)<\/td>\nExcellent<\/td>\nModerate<\/td>\nHigh<\/td>\nContinuous-duty drives, heat-sensitive applications<\/td>\n<\/tr>\n
Aluminium-iron bronze (CuAl10Fe3)<\/td>\nGood<\/td>\nHigh<\/td>\nModerate<\/td>\nImpact-loaded drives, larger modules<\/td>\n<\/tr>\n
Ductile cast iron (age-treated)<\/td>\nPoor<\/td>\nModerate<\/td>\nLow<\/td>\nSlow, non-critical drives only<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

A practical rule: tin bronze for drives that run eight or more hours a day and cannot tolerate a seize; aluminium-iron bronze for sporadic but heavy loads; cast iron only when the drive turns fewer than a handful of revolutions per day and the budget is tight. Age-treatment is compulsory on cast iron wheels because it removes internal casting stresses that would otherwise deform the wheel during machining.<\/p>\n

\"Cylindrical<\/p>\n<\/section>\n

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Performance Data: Efficiency, Contact Pattern and Backlash<\/h2>\n

The numbers below come from our QC lab, measured on a DIN 7 M5 set with an aluminium-iron bronze wheel and a ground 20CrMnTi input shaft at 1 500 rpm input, oil-bath lubricated with ISO VG 460 gear oil. They should be read as a typical range rather than a warranted figure for every lot.<\/p>\n

\n\n\n\n\n\n\n\n\n\n\n
Parameter<\/th>\nTypical Range<\/th>\nNotes<\/th>\n<\/tr>\n<\/thead>\n
Drive efficiency at 20:1<\/td>\n82 \u2013 88 %<\/td>\nGround worm, bronze wheel, oil bath<\/td>\n<\/tr>\n
Drive efficiency at 60:1<\/td>\n65 \u2013 72 %<\/td>\nSame configuration, higher ratio<\/td>\n<\/tr>\n
Contact pattern coverage<\/td>\n\u2265 60 % tooth face<\/td>\nAfter 4 h run-in at 50 % load<\/td>\n<\/tr>\n
Tooth backlash (DIN 7)<\/td>\n60 \u2013 110 \u00b5m<\/td>\nSet by centre-distance shim<\/td>\n<\/tr>\n
Oil sump temperature rise<\/td>\n30 \u2013 45 \u00b0C over ambient<\/td>\nContinuous duty, no external cooling<\/td>\n<\/tr>\n
Noise at 1 500 rpm<\/td>\n58 \u2013 64 dB at 1 m<\/td>\nIso-free test chamber<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

The efficiency gap between 20:1 and 60:1 is the single most important design lesson on these drives: every reduction point above 40:1 costs two to three percentage points of efficiency. When the downstream machine needs more than 40:1 and also needs high efficiency, combining a single-stage input with a helical or spur secondary stage is almost always cheaper than pushing the primary stage alone.<\/p>\n<\/section>\n

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Selection Guide for Cylindrical Worm Wheels<\/h2>\n

Six inputs decide most of the sizing for a new cylindrical worm drive. Getting these right on the first drawing saves weeks of back-and-forth during prototype validation.<\/p>\n