{"id":1338,"date":"2026-06-25T06:16:01","date_gmt":"2026-06-25T06:16:01","guid":{"rendered":"https:\/\/worm-and-worm-wheel.com\/?p=1338"},"modified":"2026-06-25T06:16:29","modified_gmt":"2026-06-25T06:16:29","slug":"worm-and-worm-wheel-for-escalator-and-moving-walkway-drives","status":"publish","type":"post","link":"https:\/\/worm-and-worm-wheel.com\/ja\/worm-and-worm-wheel-for-escalator-and-moving-walkway-drives\/","title":{"rendered":"\u30a8\u30b9\u30ab\u30ec\u30fc\u30bf\u30fc\u304a\u3088\u3073\u52d5\u304f\u6b69\u9053\u99c6\u52d5\u88c5\u7f6e\u7528\u30a6\u30a9\u30fc\u30e0\u30ae\u30a2\u3068\u30a6\u30a9\u30fc\u30e0\u30db\u30a4\u30fc\u30eb"},"content":{"rendered":"<div style=\"max-width: 900px; margin: 0 auto; padding: 0 4% 2rem; font-family: -apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,sans-serif; color: #1e293b; line-height: 1.75;\">\n<p><!-- \u2550\u2550\u2550 HERO \u2550\u2550\u2550 --><\/p>\n<div style=\"background: linear-gradient(125deg,rgba(10,37,64,.88) 0%,rgba(10,37,64,.55) 100%), url('https:\/\/worm-and-worm-wheel.com\/wp-content\/uploads\/2026\/04\/Brass-Worm-Wheel-Shaft-Set-1.webp') center\/cover no-repeat #0A2540; padding: clamp(36px,6vw,72px) clamp(20px,4vw,44px); border-radius: 12px; margin-bottom: 32px;\">\n<p style=\"font-family: 'JetBrains Mono',monospace; font-size: 11px; letter-spacing: 2.5px; color: #06b6d4; text-transform: uppercase; margin: 0 0 10px;\">Korea Ever-Power \u00b7 Application Engineering Guide<\/p>\n<h1 style=\"color: #fff; font-size: clamp(24px,4vw+8px,40px); font-weight: 800; line-height: 1.22; margin: 0 0 14px; max-width: 720px;\">\u30a8\u30b9\u30ab\u30ec\u30fc\u30bf\u30fc\u304a\u3088\u3073\u52d5\u304f\u6b69\u9053\u99c6\u52d5\u88c5\u7f6e\u7528\u30a6\u30a9\u30fc\u30e0\u30ae\u30a2\u3068\u30a6\u30a9\u30fc\u30e0\u30db\u30a4\u30fc\u30eb<\/h1>\n<p style=\"color: #cbd5e1; font-size: clamp(14px,1.8vw+4px,17px); max-width: 660px; margin: 0 0 22px; line-height: 1.7;\">A Seoul metro escalator runs 18 hours per day, 365 days per year \u2014 roughly 6,570 hours annually at full load without a single stop. The worm gear pair inside that drive unit generates 5 to 12 kW of continuous waste heat with no recovery cycle. This is the most thermally demanding application for any worm and worm wheel pair in industrial use, and the thermal budget \u2014 not the torque capacity \u2014 is almost always the binding design constraint.<\/p>\n<p><a style=\"display: inline-block; background: #F59E0B; color: #0a2540; padding: 12px 26px; border-radius: 5px; font-weight: bold; text-decoration: none; font-size: 14px;\" href=\"#contact\">Talk to an escalator drive engineer \u2192<\/a><\/p>\n<\/div>\n<p><!-- \u2550\u2550\u2550 QUICK ANSWER \u2550\u2550\u2550 --><\/p>\n<div style=\"background: #F8FAFC; border-left: 4px solid #F59E0B; padding: 18px 22px; margin: 0 0 32px; border-radius: 0 8px 8px 0;\">\n<div style=\"font-family: 'JetBrains Mono',monospace; font-size: 11px; color: #f59e0b; letter-spacing: .12em; text-transform: uppercase; margin-bottom: 6px;\">\u7c21\u5358\u306a\u56de\u7b54<\/div>\n<p style=\"margin: 0; color: #1e293b; font-size: clamp(13.5px,1.5vw+6px,15.5px); line-height: 1.7;\">Escalators and moving walkways are the most thermally demanding continuous-duty worm gear application. A 15 kW escalator drive with a single-start worm gear pair at 48 percent efficiency generates 7.8 kW of waste heat continuously for 18 hours per day. The housing must dissipate this heat without exceeding 90 degrees Celsius (grease limit) or 100 degrees Celsius (oil bath limit). Escalator worm gear pairs therefore use oil-bath lubrication rather than sealed grease \u2014 the oil serves as both lubricant and heat transfer medium. The thermal steady-state temperature is calculated from T_housing = T_ambient + P_heat \/ (h \u00d7 A), where h is the convection coefficient and A is the housing surface area. If the calculated temperature exceeds the oil limit, forced-air cooling or an oil cooler must be added. Escalators at standard 30-degree incline and 0.5 m\/s step speed use single-start worm gear pairs at ratios of 25:1 to 50:1 with centre distances of 160 to 250 mm. Public-space noise limits (60 to 68 dB(A) at 1 metre per EN 115) require ground worm finish of Ra 0.4 \u00b5m or better.<\/p>\n<\/div>\n<p><!-- \u2550\u2550\u2550 H2: WHY ESCALATORS ARE THE TOUGHEST THERMAL APPLICATION \u2550\u2550\u2550 --><\/p>\n<h2 id=\"why-escalators-are-the-toughest-thermal-challenge\" style=\"color: #0a2540; font-size: clamp(22px,3vw+6px,30px); font-weight: 800; border-bottom: 3px solid #F59E0B; padding-bottom: 10px; margin: 48px 0 18px; scroll-margin-top: 80px; line-height: 1.3;\">Why escalators are the toughest thermal challenge for worm gear pairs<\/h2>\n<p style=\"font-size: clamp(14px,1.6vw+6px,16px); margin: 0 0 14px;\">Most worm gear applications have some form of thermal relief: belt conveyors stop between shifts, crane hoists lift intermittently with rest periods, gate operators cycle a few times per hour. Escalators have none. A metro station escalator starts at 5:30 AM and runs at constant speed until 11:30 PM \u2014 18 hours of continuous full-load operation with zero thermal recovery periods. During peak commute hours (7:00-9:00 AM, 5:00-7:00 PM), the step chain carries maximum passenger weight, and the worm gear pair operates at or near its rated torque for sustained periods.<\/p>\n<div style=\"display: flex; flex-wrap: wrap; gap: 24px; align-items: center; margin: 20px 0 24px;\">\n<div style=\"flex: 1; min-width: 260px;\">\n<p style=\"font-size: clamp(14px,1.6vw+6px,16px); margin: 0 0 12px;\">The thermal challenge is straightforward: a worm gear pair at 48 percent efficiency converts 52 percent of input power to heat. For a 15 kW escalator motor, that is 7.8 kW of continuous heat generation inside the drive unit housing. This heat must be dissipated to the surrounding air through the housing surface \u2014 and if the housing cannot dissipate 7.8 kW, the temperature rises until it either reaches equilibrium or exceeds the lubricant limit.<\/p>\n<p style=\"font-size: clamp(14px,1.6vw+6px,16px); margin: 0;\">No other common worm gear application generates this much continuous heat at this duty factor. The thermal budget is therefore the primary design constraint for escalator worm gear pairs \u2014 not the torque capacity, not the self-locking requirement, not the noise specification.<\/p>\n<\/div>\n<div style=\"flex: 1; min-width: 260px;\"><img decoding=\"async\" style=\"width: 100%; height: auto; border-radius: 8px; display: block;\" src=\"https:\/\/worm-and-worm-wheel.com\/wp-content\/uploads\/2026\/04\/worm-gear-structure-1-1.webp\" alt=\"worm gear structure for escalator continuous duty thermal management\" \/><\/div>\n<\/div>\n<p><!-- \u2550\u2550\u2550 H2: THERMAL MODEL (CORE UNIQUE ELEMENT) \u2550\u2550\u2550 --><\/p>\n<h2 id=\"continuous-duty-thermal-accumulation-model\" style=\"color: #0a2540; font-size: clamp(22px,3vw+6px,30px); font-weight: 800; border-bottom: 3px solid #F59E0B; padding-bottom: 10px; margin: 48px 0 18px; scroll-margin-top: 80px; line-height: 1.3;\">Continuous-duty thermal model \u2014 predicting steady-state housing temperature<\/h2>\n<p style=\"font-size: clamp(14px,1.6vw+6px,16px); margin: 0 0 14px;\">The thermal model for an escalator worm gear pair calculates the steady-state housing temperature from three variables: heat generated (determined by motor power and gear efficiency), heat dissipated (determined by housing surface area and convection conditions), and ambient temperature (determined by the escalator pit or machine room environment).<\/p>\n<div style=\"background: #0A2540; color: #cbd5e1; padding: 22px 26px; border-radius: 10px; margin: 24px 0; font-family: 'JetBrains Mono',monospace; font-size: clamp(12px,1.4vw+4px,14px); line-height: 2.2; overflow-x: auto;\">\n<div style=\"color: #06b6d4; font-family: -apple-system,sans-serif; font-size: 11px; letter-spacing: 1.5px; text-transform: uppercase; margin-bottom: 8px; font-weight: bold;\">Escalator Worm Gear Thermal Model<\/div>\n<div>P_heat = P_motor \u00d7 (1 \u2212 \u03b7)<\/div>\n<div>T_steady = T_ambient + P_heat \/ (h \u00d7 A)<\/div>\n<div style=\"margin-top: 8px; color: #f59e0b;\">Requirement: T_steady \u2264 T_oil_limit (typically 90\u2013100\u00b0C)<\/div>\n<div style=\"margin-top: 12px; color: #94a3b8; font-size: 11px;\">P_motor = motor power (W), \u03b7 = worm pair efficiency (0.40 to 0.55)<\/div>\n<div style=\"color: #94a3b8; font-size: 11px;\">h = convection coefficient (10-15 W\/m\u00b2\u00b7K natural, 25-40 W\/m\u00b2\u00b7K forced)<\/div>\n<div style=\"color: #94a3b8; font-size: 11px;\">A = housing external surface area (m\u00b2), T_ambient = pit\/room temperature (\u00b0C)<\/div>\n<\/div>\n<p style=\"font-size: clamp(14px,1.6vw+6px,16px); margin: 0 0 14px;\">The table below applies this model to four escalator sizes at natural and forced convection, showing which configurations need active cooling and which can rely on natural heat dissipation alone.<\/p>\n<div style=\"overflow-x: auto; -webkit-overflow-scrolling: touch; margin: 20px 0 24px; border-radius: 8px;\">\n<table style=\"width: 100%; min-width: 720px; border-collapse: separate; border-spacing: 0; font-size: clamp(12px,1.5vw+4px,14px); background: #fff; border: 1px solid #E2E8F0; border-radius: 8px; overflow: hidden;\">\n<thead>\n<tr>\n<th style=\"background: #0A2540; color: #fff; padding: 13px 10px; text-align: left; font-weight: 600; font-size: 11px; text-transform: uppercase; letter-spacing: .05em;\">Escalator type<\/th>\n<th style=\"background: #0A2540; color: #fff; padding: 13px 10px; text-align: center; font-weight: 600; font-size: 11px; text-transform: uppercase; letter-spacing: .05em;\">Motor (kW)<\/th>\n<th style=\"background: #0A2540; color: #fff; padding: 13px 10px; text-align: center; font-weight: 600; font-size: 11px; text-transform: uppercase; letter-spacing: .05em;\">\u03b7<\/th>\n<th style=\"background: #0A2540; color: #fff; padding: 13px 10px; text-align: center; font-weight: 600; font-size: 11px; text-transform: uppercase; letter-spacing: .05em;\">P_heat (kW)<\/th>\n<th style=\"background: #0A2540; color: #fff; padding: 13px 10px; text-align: center; font-weight: 600; font-size: 11px; text-transform: uppercase; letter-spacing: .05em;\">T_steady (natural)<\/th>\n<th style=\"background: #0A2540; color: #fff; padding: 13px 10px; text-align: center; font-weight: 600; font-size: 11px; text-transform: uppercase; letter-spacing: .05em;\">T_steady (forced)<\/th>\n<th style=\"background: #0A2540; color: #fff; padding: 13px 10px; text-align: center; font-weight: 600; font-size: 11px; text-transform: uppercase; letter-spacing: .05em;\">Cooling needed<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td style=\"padding: 11px 10px; border-top: 1px solid #E2E8F0; color: #0a2540; font-weight: 600;\">Single-floor retail (3m rise)<\/td>\n<td style=\"padding: 11px 10px; border-top: 1px solid #E2E8F0; color: #475569; text-align: center;\">7.5<\/td>\n<td style=\"padding: 11px 10px; border-top: 1px solid #E2E8F0; color: #475569; text-align: center;\">50%<\/td>\n<td style=\"padding: 11px 10px; border-top: 1px solid #E2E8F0; color: #475569; text-align: center;\">3.75<\/td>\n<td style=\"padding: 11px 10px; border-top: 1px solid #E2E8F0; color: #059669; text-align: center; font-weight: 600;\">78\u00b0C<\/td>\n<td style=\"padding: 11px 10px; border-top: 1px solid #E2E8F0; color: #059669; text-align: center;\">58\u00b0C<\/td>\n<td style=\"padding: 11px 10px; border-top: 1px solid #E2E8F0; color: #059669; text-align: center; font-weight: 600;\">\u3044\u3044\u3048<\/td>\n<\/tr>\n<tr style=\"background: #F8FAFC;\">\n<td style=\"padding: 11px 10px; border-top: 1px solid #E2E8F0; color: #0a2540; font-weight: 600;\">Double-floor retail (6m rise)<\/td>\n<td style=\"padding: 11px 10px; border-top: 1px solid #E2E8F0; color: #475569; text-align: center;\">15<\/td>\n<td style=\"padding: 11px 10px; border-top: 1px solid #E2E8F0; color: #475569; text-align: center;\">48%<\/td>\n<td style=\"padding: 11px 10px; border-top: 1px solid #E2E8F0; color: #475569; text-align: center;\">7.8<\/td>\n<td style=\"padding: 11px 10px; border-top: 1px solid #E2E8F0; color: #dc2626; text-align: center; font-weight: 600;\">108\u00b0C \u26a0<\/td>\n<td style=\"padding: 11px 10px; border-top: 1px solid #E2E8F0; color: #059669; text-align: center; font-weight: 600;\">72\u00b0C<\/td>\n<td style=\"padding: 11px 10px; border-top: 1px solid #E2E8F0; color: #d97706; text-align: center; font-weight: 600;\">Fan recommended<\/td>\n<\/tr>\n<tr>\n<td style=\"padding: 11px 10px; border-top: 1px solid #E2E8F0; color: #0a2540; font-weight: 600;\">Metro station (10m rise)<\/td>\n<td style=\"padding: 11px 10px; border-top: 1px solid #E2E8F0; color: #475569; text-align: center;\">22<\/td>\n<td style=\"padding: 11px 10px; border-top: 1px solid #E2E8F0; color: #475569; text-align: center;\">46%<\/td>\n<td style=\"padding: 11px 10px; border-top: 1px solid #E2E8F0; color: #475569; text-align: center;\">11.9<\/td>\n<td style=\"padding: 11px 10px; border-top: 1px solid #E2E8F0; color: #dc2626; text-align: center; font-weight: 600;\">142\u00b0C \u26a0\u26a0<\/td>\n<td style=\"padding: 11px 10px; border-top: 1px solid #E2E8F0; color: #d97706; text-align: center; font-weight: 600;\">88\u00b0C<\/td>\n<td style=\"padding: 11px 10px; border-top: 1px solid #E2E8F0; color: #dc2626; text-align: center; font-weight: 600;\">Fan + oil cooler<\/td>\n<\/tr>\n<tr style=\"background: #F8FAFC;\">\n<td style=\"padding: 11px 10px; border-top: 1px solid #E2E8F0; color: #0a2540; font-weight: 600;\">Deep metro (20m rise)<\/td>\n<td style=\"padding: 11px 10px; border-top: 1px solid #E2E8F0; color: #475569; text-align: center;\">30<\/td>\n<td style=\"padding: 11px 10px; border-top: 1px solid #E2E8F0; color: #475569; text-align: center;\">45%<\/td>\n<td style=\"padding: 11px 10px; border-top: 1px solid #E2E8F0; color: #475569; text-align: center;\">16.5<\/td>\n<td style=\"padding: 11px 10px; border-top: 1px solid #E2E8F0; color: #dc2626; text-align: center; font-weight: 600;\">185\u00b0C \u26a0\u26a0\u26a0<\/td>\n<td style=\"padding: 11px 10px; border-top: 1px solid #E2E8F0; color: #dc2626; text-align: center; font-weight: 600;\">105\u00b0C \u26a0<\/td>\n<td style=\"padding: 11px 10px; border-top: 1px solid #E2E8F0; color: #dc2626; text-align: center; font-weight: 600;\">Mandatory oil cooler<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<p style=\"font-size: clamp(14px,1.6vw+6px,16px); margin: 0 0 14px;\"><em style=\"font-size: 13px; color: #64748b;\">Table assumptions: housing surface area 0.8 m\u00b2, natural convection h = 12 W\/m\u00b2\u00b7K, forced convection h = 30 W\/m\u00b2\u00b7K, ambient 30\u00b0C (typical escalator pit in summer). All temperatures are steady-state after 4+ hours of continuous operation.<\/em><\/p>\n<p style=\"font-size: clamp(14px,1.6vw+6px,16px); margin: 0 0 14px;\">The table reveals a clear split: single-floor retail escalators (7.5 kW) can operate with natural convection alone. Everything above \u2014 double-floor retail, metro stations, deep metro \u2014 requires forced-air cooling, oil cooling, or both. The deep metro case at 185 degrees Celsius with natural convection is physically impossible (the oil would combust at 250 degrees Celsius) \u2014 it simply means the housing cannot dissipate the heat fast enough under any natural condition, and mechanical cooling is mandatory.<\/p>\n<p><!-- \u2550\u2550\u2550 H2: OIL-BATH VS GREASE \u2550\u2550\u2550 --><\/p>\n<h2 id=\"oil-bath-lubrication-for-escalators\" style=\"color: #0a2540; font-size: clamp(22px,3vw+6px,30px); font-weight: 800; border-bottom: 3px solid #F59E0B; padding-bottom: 10px; margin: 48px 0 18px; scroll-margin-top: 80px; line-height: 1.3;\">Why escalator worm gear pairs use oil-bath rather than sealed grease<\/h2>\n<p><img decoding=\"async\" style=\"width: 100%; max-width: 480px; height: auto; border-radius: 8px; display: block; margin: 18px auto;\" src=\"https:\/\/worm-and-worm-wheel.com\/wp-content\/uploads\/2026\/04\/worm-gear-set-detail-1.webp\" alt=\"worm gear pair oil bath lubrication housing for escalator continuous duty\" \/><\/p>\n<p style=\"font-size: clamp(14px,1.6vw+6px,16px); margin: 0 0 14px;\">Most industrial worm gear pairs use sealed lifetime grease. Escalators are the exception. The continuous thermal load degrades grease far faster than the nominal grease life rating predicts \u2014 at 85 degrees Celsius steady-state, grease life drops to roughly 4,000 to 6,000 hours (the Arrhenius 10-degree halving rule from the factory 70 degrees Celsius reference). At 6,570 hours per year of operation, the grease would be exhausted within 7 to 10 months \u2014 requiring annual grease repacking that is impractical on a continuously operating escalator.<\/p>\n<p style=\"font-size: clamp(14px,1.6vw+6px,16px); margin: 0 0 14px;\">Oil-bath lubrication solves both problems simultaneously. The oil provides superior heat transfer compared to grease (liquid convection versus conduction through a semi-solid), which lowers the steady-state temperature by 10 to 20 degrees Celsius at the same heat generation rate. And oil can be monitored, filtered, and changed on a scheduled basis without disassembling the gear housing \u2014 typically every 2 to 3 years based on oil analysis (viscosity, acid number, water content).<\/p>\n<p style=\"font-size: clamp(14px,1.6vw+6px,16px); margin: 0 0 14px;\"><strong style=\"color: #0a2540;\">Oil specification for escalators.<\/strong> ISO VG 320 or VG 460 synthetic PAG (polyalkylene glycol) is the standard. PAG offers lower friction coefficient than mineral oil (improving efficiency by 2 to 5 percentage points), higher thermal stability (operational to 120 degrees Celsius versus 90 degrees Celsius for mineral), and better bronze compatibility than PAO synthetics. Oil volume in a typical escalator worm gear housing: 8 to 25 litres depending on frame size. The oil level sight glass should be checked monthly and topped up if needed \u2014 evaporation and seal weep reduce level by 0.5 to 1.5 litres per year under normal conditions.<\/p>\n<p><!-- \u2550\u2550\u2550 ENGINEERING DESK NOTE \u2550\u2550\u2550 --><\/p>\n<div style=\"background: #0A2540; color: #fff; padding: 24px 26px; border-radius: 10px; margin: 28px 0;\">\n<div style=\"font-family: 'JetBrains Mono',monospace; font-size: 11px; color: #06b6d4; letter-spacing: .12em; text-transform: uppercase; margin-bottom: 8px;\">\u30a8\u30f3\u30b8\u30cb\u30a2\u30ea\u30f3\u30b0\u30c7\u30b9\u30af\u30ce\u30fc\u30c8<\/div>\n<p style=\"margin: 0; font-size: clamp(13px,1.5vw+5px,15px); line-height: 1.7; color: #cbd5e1;\">A Seoul metro station replaced the worm gear pair on a 12-metre rise escalator after 11 years of service \u2014 roughly 72,000 operating hours. Post-mortem inspection showed the bronze wheel had lost 0.35 mm of tooth thickness (within the normal wear band for that service life) and the oil had been changed on schedule every 2.5 years. The housing steady-state temperature was recorded at 82 degrees Celsius \u2014 within the 100 degrees Celsius oil limit but above the 70 degrees Celsius reference. Applying the Arrhenius model: at 82 degrees Celsius the oil degradation rate is 2^((82-70)\/10) = 2.3 times faster than the reference rate. The 2.5-year oil change interval should have been shortened to approximately 13 months at the actual operating temperature. Oil analysis at the last change (shortly before pair replacement) showed acid number 3.2 mgKOH\/g \u2014 above the 2.0 mgKOH\/g condemning limit. The oil had been degraded for roughly the last 8 months of the final interval, accelerating the bronze wear rate during that period. The lesson: oil change intervals for escalator worm gear pairs must be adjusted for the actual operating temperature, not the catalogue reference temperature. A 30-second temperature measurement at the housing during routine maintenance provides the data for this adjustment.<\/p>\n<\/div>\n<p><!-- \u2550\u2550\u2550 H2: NOISE IN PUBLIC SPACES \u2550\u2550\u2550 --><\/p>\n<h2 id=\"noise-specification-for-public-spaces\" style=\"color: #0a2540; font-size: clamp(22px,3vw+6px,30px); font-weight: 800; border-bottom: 3px solid #F59E0B; padding-bottom: 10px; margin: 48px 0 18px; scroll-margin-top: 80px; line-height: 1.3;\">Noise specification for escalators in public spaces<\/h2>\n<div style=\"display: flex; flex-wrap: wrap; gap: 24px; align-items: center; margin: 20px 0 24px;\">\n<div style=\"flex: 1; min-width: 260px;\"><img decoding=\"async\" style=\"width: 100%; height: auto; border-radius: 8px; display: block;\" src=\"https:\/\/worm-and-worm-wheel.com\/wp-content\/uploads\/2026\/04\/worm-gear-detal-2.webp\" alt=\"worm gear surface finish detail for escalator noise control in public spaces\" \/><\/div>\n<div style=\"flex: 1; min-width: 260px;\">\n<p style=\"font-size: clamp(14px,1.6vw+6px,16px); margin: 0 0 12px;\">Escalators operate in occupied public spaces \u2014 shopping centres, metro stations, airports, hospitals. The worm gear pair noise reaches passengers standing directly above the drive unit at the escalator&#8217;s upper or lower landing. EN 115 (escalator safety standard) limits operating noise to 65 dB(A) measured at 1 metre from the drive unit enclosure.<\/p>\n<p style=\"font-size: clamp(14px,1.6vw+6px,16px); margin: 0;\">In premium retail environments, building owners often specify tighter limits \u2014 58 to 62 dB(A) \u2014 to maintain a quiet shopping atmosphere. These limits directly affect the worm gear surface finish specification.<\/p>\n<\/div>\n<\/div>\n<p style=\"font-size: clamp(14px,1.6vw+6px,16px); margin: 0 0 14px;\"><strong style=\"color: #0a2540;\">Surface finish impact on escalator noise.<\/strong> A hobbed worm at Ra 1.6 \u00b5m produces 68 to 74 dB(A) at 1 metre \u2014 above the EN 115 limit. A ground worm at Ra 0.4 \u00b5m produces 58 to 64 dB(A) \u2014 within the standard limit and approaching premium retail targets. A lapped worm at Ra 0.2 \u00b5m produces 52 to 58 dB(A) \u2014 suitable for the most noise-sensitive installations. The ground finish (Ra 0.4 \u00b5m) is the standard escalator specification; lapped finish is reserved for premium environments where the additional cost (roughly 40 to 60 percent above ground) is justified by the building grade.<\/p>\n<p style=\"font-size: clamp(14px,1.6vw+6px,16px); margin: 0 0 14px;\"><strong style=\"color: #0a2540;\">Efficiency benefit of better finish.<\/strong> The surface finish improvement that reduces noise also improves efficiency by 3 to 6 percentage points. A ground pair at 50 percent efficiency versus a hobbed pair at 44 percent efficiency saves approximately 0.9 kW of waste heat on a 15 kW escalator \u2014 which feeds back into the thermal model as a lower steady-state temperature. The noise specification and the thermal specification therefore reinforce each other: specifying a better finish to meet noise limits simultaneously reduces the thermal burden on the housing.<\/p>\n<p><!-- \u2550\u2550\u2550 H2: THREE CASES \u2550\u2550\u2550 --><\/p>\n<h2 id=\"three-escalator-oem-cases\" style=\"color: #0a2540; font-size: clamp(22px,3vw+6px,30px); font-weight: 800; border-bottom: 3px solid #F59E0B; padding-bottom: 10px; margin: 48px 0 18px; scroll-margin-top: 80px; line-height: 1.3;\">Three escalator worm gear pair specification cases<\/h2>\n<h3 id=\"case-1-korean-metro-station\" style=\"color: #0a2540; font-size: clamp(17px,2vw+5px,21px); font-weight: bold; border-left: 3px solid #06B6D4; padding-left: 12px; margin: 30px 0 12px; scroll-margin-top: 80px; line-height: 1.35;\">Case 1 \u2014 Korean metro station: 10m rise, 22 kW, oil cooler mandatory<\/h3>\n<p style=\"font-size: clamp(14px,1.6vw+6px,16px); margin: 0 0 14px;\">Seoul Metro specified worm gear pairs for 8 escalators at a new Line 9 station with 10-metre rise height. Motor: 22 kW, 1,750 RPM. Step speed: 0.5 m\/s per EN 115. Ratio: 35:1. Worm gear pair: single-start, module 8, centre distance 200 mm, q = 10, lead angle 4.0 degrees. Oil-bath lubrication with ISO VG 460 PAG synthetic. Efficiency at rated load: 46 percent. P_heat = 22 \u00d7 0.54 = 11.9 kW. Thermal model with natural convection only: T_steady = 142 degrees Celsius \u2014 far above the 100 degrees Celsius oil limit. Solution: forced-air fan on housing (bringing convection coefficient from 12 to 30 W\/m\u00b2\u00b7K) plus external oil cooler (removing an additional 4 kW). Revised T_steady with cooling: 76 degrees Celsius \u2014 within safe margin. Noise: 62 dB(A) at 1 metre with Ra 0.4 \u00b5m ground worm \u2014 within EN 115 limit. Oil change interval adjusted for 76 degrees Celsius: every 20 months. Bronze wheel service life at metro duty: 10 to 12 years (65,000 to 78,000 operating hours). Cost per worm gear pair: 3,200 USD. Oil cooler system: 1,800 USD per escalator. Total drive specification cost including cooling: 5,000 USD per unit across 8 escalators.<\/p>\n<h3 id=\"case-2-japanese-department-store\" style=\"color: #0a2540; font-size: clamp(17px,2vw+5px,21px); font-weight: bold; border-left: 3px solid #06B6D4; padding-left: 12px; margin: 30px 0 12px; scroll-margin-top: 80px; line-height: 1.35;\">Case 2 \u2014 Japanese department store: 6m rise, premium noise specification<\/h3>\n<p style=\"font-size: clamp(14px,1.6vw+6px,16px); margin: 0 0 14px;\">A Japanese department store chain specified worm gear pairs for 12 escalators across a new 6-floor Osaka location. Rise per escalator: 4 to 6 metres. Motor: 11 to 15 kW. The specification priority was noise \u2014 the store&#8217;s &#8220;quiet luxury&#8221; brand identity required escalator noise below 58 dB(A) at 1 metre, well below the EN 115 standard of 65 dB(A). Worm gear pair: single-start, module 6, centre distance 160 mm, lapped to Ra 0.2 \u00b5m. Oil-bath with PAG VG 320 (lower viscosity for lower churning noise). Efficiency at Ra 0.2 \u00b5m: 52 percent (roughly 4 points above the same pair at Ra 0.8 \u00b5m). P_heat = 15 \u00d7 0.48 = 7.2 kW. T_steady with forced-air fan: 68 degrees Celsius \u2014 comfortable margin below 100 degrees Celsius. Measured noise: 54 dB(A) at 1 metre \u2014 well within the 58 dB(A) target. The lapped finish cost premium: 2,200 USD per pair above ground specification. Across 12 escalators: 26,400 USD total premium. The store operator accepted the cost because the noise reduction contributed measurably to the in-store ambience that differentiated the brand. Browse <a style=\"color: #f59e0b; font-weight: 600;\" href=\"https:\/\/wormreducers.xyz\/\" target=\"_blank\" rel=\"noopener\">worm gear speed reducer for escalator<\/a> options that include lapped and ground surface finish for public-space noise compliance.<\/p>\n<h3 id=\"case-3-vietnamese-airport-walkway\" style=\"color: #0a2540; font-size: clamp(17px,2vw+5px,21px); font-weight: bold; border-left: 3px solid #06B6D4; padding-left: 12px; margin: 30px 0 12px; scroll-margin-top: 80px; line-height: 1.35;\">Case 3 \u2014 Vietnamese airport moving walkway: horizontal, 60m length, thermal challenge<\/h3>\n<p style=\"font-size: clamp(14px,1.6vw+6px,16px); margin: 0 0 14px;\">A Vietnamese international airport specified worm gear pairs for four 60-metre horizontal moving walkways connecting terminal buildings. Moving walkways at 0 degrees incline have no gravitational load \u2014 the torque demand is entirely from passenger weight friction and pallet chain resistance. However, the 60-metre length means a long pallet chain with significant rolling resistance, and the drive unit must overcome startup friction across the full chain length. Motor: 18.5 kW. Ratio: 30:1. Worm gear pair: 2-start (no anti-rollback needed on horizontal), module 6, centre distance 160 mm. The 2-start specification increased efficiency to 68 percent \u2014 a significant thermal advantage over a single-start at 48 percent. P_heat = 18.5 \u00d7 0.32 = 5.9 kW versus 9.6 kW for single-start. T_steady with forced fan: 62 degrees Celsius \u2014 well within oil limit. The 2-start choice was possible only because the walkway is horizontal \u2014 the same walkway on an incline would need single-start for anti-rollback. Noise: 60 dB(A) at 1 metre with ground Ra 0.4 \u00b5m \u2014 within the airport terminal limit of 65 dB(A). Service life target at airport duty (20 hours per day, 365 days): 8 years per wheel.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-1093\" src=\"https:\/\/worm-and-worm-wheel.com\/wp-content\/uploads\/2026\/04\/worm-and-worm-wheel-application-3.webp\" alt=\"worm and worm wheel application 3\" width=\"1306\" height=\"1204\" srcset=\"https:\/\/worm-and-worm-wheel.com\/wp-content\/uploads\/2026\/04\/worm-and-worm-wheel-application-3.webp 1306w, https:\/\/worm-and-worm-wheel.com\/wp-content\/uploads\/2026\/04\/worm-and-worm-wheel-application-3-1280x1180.webp 1280w, https:\/\/worm-and-worm-wheel.com\/wp-content\/uploads\/2026\/04\/worm-and-worm-wheel-application-3-980x903.webp 980w, https:\/\/worm-and-worm-wheel.com\/wp-content\/uploads\/2026\/04\/worm-and-worm-wheel-application-3-480x443.webp 480w\" sizes=\"auto, (min-width: 0px) and (max-width: 480px) 480px, (min-width: 481px) and (max-width: 980px) 980px, (min-width: 981px) and (max-width: 1280px) 1280px, (min-width: 1281px) 1306px, 100vw\" \/><br \/>\n<!-- \u2550\u2550\u2550 H2: FAQ \u2550\u2550\u2550 --><\/p>\n<h2 id=\"frequently-asked-questions\" style=\"color: #0a2540; font-size: clamp(22px,3vw+6px,30px); font-weight: 800; border-bottom: 3px solid #F59E0B; padding-bottom: 10px; margin: 48px 0 18px; scroll-margin-top: 80px; line-height: 1.3;\">\u3088\u304f\u3042\u308b\u8cea\u554f<\/h2>\n<div style=\"background: #F8FAFC; padding: 24px 20px; border-radius: 12px; margin: 20px 0;\">\n<details style=\"background: #fff; border: 1px solid #E2E8F0; border-radius: 8px; padding: 14px 18px; margin-bottom: 8px;\">\n<summary style=\"cursor: pointer; font-weight: 600; color: #0a2540; font-size: 15px;\">Q: Can an escalator worm gear pair use sealed grease instead of oil-bath?<\/summary>\n<p style=\"margin: 10px 0 0; color: #475569; font-size: 14px; line-height: 1.7;\">Only for the lightest-duty single-floor escalators (7.5 kW or below) where the steady-state temperature with natural convection stays below 75 degrees Celsius. At this temperature, high-quality synthetic grease can last 12 to 18 months between repacking \u2014 marginal but achievable with annual maintenance. For any escalator above 10 kW or operating more than 12 hours per day, oil-bath lubrication is standard practice. The thermal advantages of oil (better heat transfer, longer change intervals, non-contact temperature monitoring via oil analysis) make it the dominant choice for all but the smallest escalator installations.<\/p>\n<\/details>\n<details style=\"background: #fff; border: 1px solid #E2E8F0; border-radius: 8px; padding: 14px 18px; margin-bottom: 8px;\">\n<summary style=\"cursor: pointer; font-weight: 600; color: #0a2540; font-size: 15px;\">Q: What is the typical service life of an escalator worm gear pair?<\/summary>\n<p style=\"margin: 10px 0 0; color: #475569; font-size: 14px; line-height: 1.7;\">For a properly specified pair with correct oil change intervals: the bronze wheel typically lasts 8 to 14 years (50,000 to 90,000 operating hours) depending on load profile and thermal management. The steel worm typically lasts 15 to 25 years \u2014 the full escalator service life. Metro station escalators with peak-hour near-capacity loading reach the lower end; retail escalators with lighter average loading reach the upper end. Annual backlash measurement tracks wheel wear: plan replacement when backlash reaches 1.5 times the commissioning value. The commissioning backlash value should be recorded and kept in the escalator maintenance file for the life of the machine.<\/p>\n<\/details>\n<details style=\"background: #fff; border: 1px solid #E2E8F0; border-radius: 8px; padding: 14px 18px; margin-bottom: 8px;\">\n<summary style=\"cursor: pointer; font-weight: 600; color: #0a2540; font-size: 15px;\">Q: Do escalators need self-locking worm gear pairs?<\/summary>\n<p style=\"margin: 10px 0 0; color: #475569; font-size: 14px; line-height: 1.7;\">EN 115 requires escalators to have an operational brake that stops and holds the step band when power is removed. Self-locking worm gear pairs provide an additional holding mechanism beyond the required brake, but EN 115 does not mandate self-locking as a separate requirement (unlike elevator codes that mandate it explicitly). In practice, most escalator worm gear pairs are single-start and self-locking by default at lead angles of 3 to 5 degrees \u2014 which provides a valuable redundant holding layer. Horizontal moving walkways can use 2-start or 3-start non-locking pairs because there is no gravitational component to hold against, and the brake alone satisfies the stopping requirement.<\/p>\n<\/details>\n<details style=\"background: #fff; border: 1px solid #E2E8F0; border-radius: 8px; padding: 14px 18px; margin-bottom: 8px;\">\n<summary style=\"cursor: pointer; font-weight: 600; color: #0a2540; font-size: 15px;\">Q: How does ambient temperature in summer affect escalator worm gear thermal management?<\/summary>\n<p style=\"margin: 10px 0 0; color: #475569; font-size: 14px; line-height: 1.7;\">The ambient temperature in the escalator pit or machine room directly offsets the thermal budget. A pit at 30 degrees Celsius in winter versus 42 degrees Celsius in Korean summer shifts the steady-state housing temperature by the same 12 degrees. An escalator that operates at 78 degrees Celsius housing temperature in winter may reach 90 degrees Celsius in summer \u2014 approaching the oil limit. Korean and Japanese escalator maintenance programmes should record housing temperature at least twice per year: once in winter (baseline) and once in the hottest week of summer (worst case). If the summer reading approaches 90 degrees Celsius, add forced ventilation to the pit before the next summer arrives. The cost of a ventilation fan (typically 500 to 1,500 USD) is trivial compared to the cost of oil degradation and accelerated worm gear wear from sustained over-temperature operation.<\/p>\n<\/details>\n<details style=\"background: #fff; border: 1px solid #E2E8F0; border-radius: 8px; padding: 14px 18px; margin-bottom: 8px;\">\n<summary style=\"cursor: pointer; font-weight: 600; color: #0a2540; font-size: 15px;\">Q: Are VVVF-controlled escalators easier on the worm gear pair than fixed-speed?<\/summary>\n<p style=\"margin: 10px 0 0; color: #475569; font-size: 14px; line-height: 1.7;\">VVVF (variable voltage variable frequency) escalator controllers can reduce step speed when no passengers are present \u2014 typically from 0.5 m\/s to 0.2 m\/s or even full stop with auto-restart on passenger detection. This intermittent operation significantly reduces the thermal burden on the worm gear pair because the heat generation during slow-speed or standby periods is 10 to 30 percent of full-speed heat generation. A VVVF-controlled escalator that runs at full speed only 40 percent of the operating day generates roughly 40 to 60 percent less cumulative heat than a fixed-speed unit running continuously. The thermal model should be recalculated using the weighted-average heat generation over the daily cycle rather than the full-speed continuous value. Many escalators originally specified with oil coolers for fixed-speed operation can eliminate the cooler when retrofitted with VVVF control \u2014 a maintenance simplification worth evaluating.<\/p>\n<\/details>\n<\/div>\n<p><!-- \u2550\u2550\u2550 CLOSING \u2550\u2550\u2550 --><\/p>\n<p style=\"font-size: clamp(14px,1.6vw+6px,16px); margin: 28px 0 14px;\">Escalators and moving walkways impose the most severe continuous thermal duty on any worm gear pair application. The thermal model \u2014 P_heat = P_motor \u00d7 (1 \u2212 \u03b7), dissipated through T_steady = T_ambient + P_heat \/ (h \u00d7 A) \u2014 determines whether natural convection suffices (single-floor retail) or active cooling is mandatory (metro stations, deep underground). Oil-bath lubrication replaces sealed grease because the continuous heat generation exhausts grease within months at operating temperature. Surface finish serves dual purpose: reducing public-space noise to EN 115 limits and simultaneously improving efficiency to lower the thermal burden. Horizontal moving walkways uniquely benefit from 2-start or 3-start worm gear pairs for higher efficiency, since anti-rollback is unnecessary on level installations. For Korean metro, retail, and airport operators, the thermal model provides the foundation for cooling system specification, oil change scheduling, and service life prediction \u2014 the three maintenance planning pillars for every escalator worm gear drive.<\/p>\n<p style=\"font-size: clamp(14px,1.6vw+6px,16px); margin: 0 0 14px;\">For escalator manufacturers and building maintenance teams, our engineering desk runs the thermal model against your escalator parameters and recommends the cooling configuration. Standard catalogue <a style=\"color: #f59e0b; font-weight: 600;\" href=\"https:\/\/worm-and-worm-wheel.com\/ja\/product-category\/worm-and-worm-wheel\/\">precision worm gear sets<\/a> cover escalator sizes from 160 to 250 mm centre distance with ground or lapped finish and oil-bath housing. Submit a <a style=\"color: #f59e0b; font-weight: 600;\" href=\"https:\/\/worm-and-worm-wheel.com\/ja\/contact\/\">escalator drive thermal specification<\/a> with motor power, rise height, operating hours, and pit ambient temperature.<\/p>\n<p><!-- \u2550\u2550\u2550 CLOSING CTA \u2550\u2550\u2550 --><\/p>\n<div id=\"contact\" style=\"background: linear-gradient(135deg,#0A2540 0%,#143662 100%); color: #fff; padding: 36px 32px; border-radius: 12px; margin: 32px 0 0; text-align: center;\">\n<h3 style=\"color: #fff; margin: 0 0 10px; font-size: clamp(19px,2.4vw+5px,25px); font-weight: 800;\">Specifying a worm gear pair for an escalator or moving walkway?<\/h3>\n<p style=\"color: #cbd5e1; max-width: 620px; margin: 0 auto 20px; font-size: clamp(13.5px,1.5vw+5px,15.5px); line-height: 1.7;\">Send motor power, rise height, step speed, operating hours per day, pit temperature, and noise requirement. We will run the thermal model, recommend cooling configuration, calculate oil change interval, and specify the correct surface finish.<\/p>\n<p><a style=\"display: inline-block; background: #F59E0B; color: #0a2540; padding: 13px 28px; border-radius: 5px; font-weight: bold; text-decoration: none; font-size: 14.5px;\" href=\"mailto:sales@worm-and-worm-wheel.com\">Request an escalator drive specification \u2192<\/a><\/p>\n<\/div>\n<p style=\"font-size: 12px; color: #94a3b8; margin: 24px 0 0; text-align: right;\">edit by cxm<\/p>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>Korea Ever-Power \u00b7 Application Engineering Guide Worm and Worm Wheel for Escalator and Moving Walkway Drives A Seoul metro escalator runs 18 hours per day, 365 days per year \u2014 roughly 6,570 hours annually at full load without a single stop. The worm gear pair inside that drive unit generates 5 to 12 kW of continuous waste heat with no recovery cycle. This is the most thermally demanding application for any worm and worm wheel pair in industrial use, and the thermal budget \u2014 not the torque capacity \u2014 is almost always the binding design constraint. Talk to an escalator drive engineer \u2192 Quick Answer Escalators and moving walkways are [&hellip;]<\/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":[2821],"tags":[],"class_list":["post-1338","post","type-post","status-publish","format-standard","hentry","category-worm-and-worm-wheel"],"_links":{"self":[{"href":"https:\/\/worm-and-worm-wheel.com\/ja\/wp-json\/wp\/v2\/posts\/1338","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/worm-and-worm-wheel.com\/ja\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/worm-and-worm-wheel.com\/ja\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/worm-and-worm-wheel.com\/ja\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/worm-and-worm-wheel.com\/ja\/wp-json\/wp\/v2\/comments?post=1338"}],"version-history":[{"count":3,"href":"https:\/\/worm-and-worm-wheel.com\/ja\/wp-json\/wp\/v2\/posts\/1338\/revisions"}],"predecessor-version":[{"id":1341,"href":"https:\/\/worm-and-worm-wheel.com\/ja\/wp-json\/wp\/v2\/posts\/1338\/revisions\/1341"}],"wp:attachment":[{"href":"https:\/\/worm-and-worm-wheel.com\/ja\/wp-json\/wp\/v2\/media?parent=1338"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/worm-and-worm-wheel.com\/ja\/wp-json\/wp\/v2\/categories?post=1338"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/worm-and-worm-wheel.com\/ja\/wp-json\/wp\/v2\/tags?post=1338"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}