{"id":1611,"date":"2026-07-15T03:49:57","date_gmt":"2026-07-15T03:49:57","guid":{"rendered":"https:\/\/gearrack.top\/product\/ring-gear-for-wind-turbine-42crmo-mn6-z109-din-cl-7\/"},"modified":"2026-07-15T04:00:24","modified_gmt":"2026-07-15T04:00:24","slug":"ring-gear-for-wind-turbine","status":"publish","type":"product","link":"https:\/\/gearrack.top\/it\/product\/ring-gear-for-wind-turbine\/","title":{"rendered":"Ring Gear for Wind Turbine – 42CrMo, Mn6 Z109, DIN Cl.7"},"content":{"rendered":"
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<\/p>\n

Product Overview<\/h2>\n
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\"Stainless<\/div>\n
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Ring gears for wind turbines<\/strong> are among the most demanding large-format ring gear applications in industrial power transmission. The wind turbine’s main gearbox uses a multi-stage planetary arrangement where the ring gear is the primary structural and load-carrying element \u2014 fixed to the gearbox housing while the rotor-connected planet carrier drives multiple planet gears simultaneously. At rated power, a 2 MW wind turbine’s first-stage planetary ring gear may carry 1.5\u20132.5 MNm of reaction torque in continuous operation, exposed to variable loads from fluctuating wind speed, shock loads from gusts, and thermal cycling from ambient temperature changes. Korea Ever-Power manufactures wind turbine ring gears in 42CrMo alloy steel to DIN 3962 Class 7 \u2014 with full manufacturing capability to OD 2,500 mm and module up to 45 mm (after tooth grinding).<\/p>\n

Ring gears have a diversified industry presence and are typically used in passenger cars, trucks, tractors, earth moving equipment, marine engines, lawn mowers, and industrial\/power generation. Wind turbine ring gears<\/a> represent the largest and most demanding end of this range. Korea Ever-Power is a factory \u2014 size per drawing, material and specifications per requirement, free samples available.<\/p>\n<\/div>\n<\/div>\n

One of the critical ring gear applications sits on the engine flywheel and engages with the pinion of the starter motor to crank the engine upon starting \u2014 the flywheel ring gear transfers starting torque from starter to engine crankshaft. While the flywheel ring gear (external teeth) and the wind turbine planetary ring gear (internal teeth) both take the annular form, they differ fundamentally in tooth location, tooth size, and structural function. Korea Ever-Power produces both types; this page covers the large internal ring gear for wind turbine planetary gearboxes.<\/p>\n

<\/p>\n

Gear Basic Data and Specifications<\/h2>\n
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Standard Wind Turbine Ring Gear \u2014 Basic Data<\/p>\n

\n\n\n\n\n\n\n\n\n\n\n\n
Gear Basic Data<\/th>\n<\/tr>\n<\/thead>\n
Gear Tooth Shape<\/td>\nInvolute<\/td>\n<\/tr>\n
Gear Material<\/td>\n42CrMo (standard)<\/td>\n<\/tr>\n
Gear Process<\/td>\nForging \u2192 hobbing\/milling \u2192 internal grinding \u2192 plane grinding \u2192 tooth grinding<\/td>\n<\/tr>\n
Pressure Angle<\/td>\n20\u00b0<\/td>\n<\/tr>\n
Quality Level<\/td>\nDIN 3962 Class 7<\/td>\n<\/tr>\n
Gear Type (standard)<\/td>\nMn=6, Z=109, \u03b2=0\u00b0, X=\u22120.25<\/td>\n<\/tr>\n
Size<\/td>\nAccording to drawing<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n
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Technical Detail \u2014 Materials and Tolerances<\/p>\n

\n\n\n\n\n\n\n\n\n\n\n\n\n
Technical Parameters<\/th>\n<\/tr>\n<\/thead>\n
OD Tolerance<\/td>\n\u00b10.005 mm<\/td>\n<\/tr>\n
Length Tolerance<\/td>\n\u00b10.05 mm<\/td>\n<\/tr>\n
Teeth Accuracy<\/td>\nDIN Class 4 \/ ISO Class 4 \/ AGMA 13 \/ JIS Class 0<\/td>\n<\/tr>\n
Module Range<\/td>\n1.0\u20138.0+ (standard); custom on request<\/td>\n<\/tr>\n
Heat Treatment<\/td>\nQ&T; carburising & quenching; induction hardening; carbonitriding<\/td>\n<\/tr>\n
Surface Treatment<\/td>\nBlacking, polishing, anodisation, chrome, zinc, nickel plating<\/td>\n<\/tr>\n
Delivery (stock)<\/td>\n5\u201310 days<\/td>\n<\/tr>\n
Delivery (custom)<\/td>\n15\u201320 days per quantity<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n

 <\/p>\n

Internal Gear Manufacturing Capabilities<\/h2>\n

\"types<\/p>\n

\n\n\n\n\n\n\n\n\n\n\n\n
Parameter<\/th>\nMilling<\/th>\nShaping<\/th>\nTooth Grinding \u2605<\/th>\n<\/tr>\n<\/thead>\n
Maximum OD<\/td>\n2,500 mm<\/td>\n2,500 mm<\/td>\n2,500 mm \u2713<\/td>\n<\/tr>\n
Minimum ID<\/td>\n650 mm<\/td>\n50 mm<\/td>\n100 mm<\/td>\n<\/tr>\n
Maximum Face Width<\/td>\n500 mm<\/td>\n500 mm<\/td>\n500 mm<\/td>\n<\/tr>\n
Maximum Module<\/td>\n26 mm<\/td>\n26 mm<\/td>\n45 mm \u2713<\/td>\n<\/tr>\n
Accuracy Level<\/td>\nDIN Class 8<\/td>\nDIN Class 8<\/td>\nDIN Class 4 \u2713<\/td>\n<\/tr>\n
Tooth Surface Finish<\/td>\nRa 3.2<\/td>\nRa 3.2<\/td>\nRa 0.6 \u2713<\/td>\n<\/tr>\n
Max Helix Angle<\/td>\n\u00b122.5\u00b0<\/td>\n\u00b122.5\u00b0<\/td>\n\u00b145\u00b0 \u2713<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

\u2605 Tooth grinding is the process used for wind turbine ring gears at DIN Class 4\u20137 accuracy \u2014 the only process capable of achieving Ra 0.6 tooth surface finish after heat treatment at large module sizes.<\/p>\n

<\/p>\n

42CrMo \u2014 The Standard Material for Wind Turbine Ring Gears<\/h2>\n

\"measuring<\/p>\n

42CrMo (DIN 42CrMo4, AISI 4140) is the most widely specified steel grade for wind turbine planetary ring gears worldwide. Its combination of high hardenability (the chromium-molybdenum alloying elements allow deep hardening of the large cross-sections typical of wind turbine ring gears), high toughness after quench and temper heat treatment, and good machinability make it the standard specification for all major wind turbine OEM gearbox ring gears at module 4\u201310.<\/p>\n

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Deep Hardenability<\/h3>\n

42CrMo’s chromium-molybdenum alloying allows the quench hardening effect to penetrate deeply into large cross-sections \u2014 a wind turbine ring gear blank may be 200\u2013500 mm thick at the rim. Without adequate hardenability, the centre of the rim would remain soft after quenching, resulting in lower core toughness and risk of brittle fracture initiation at the core under the bending stresses at the tooth root.<\/p>\n<\/div>\n

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Fatigue Resistance at Low Temperature<\/h3>\n

Wind turbines operate in environments down to \u221230\u00b0C to \u221240\u00b0C in northern climates. At low temperatures, steel’s fracture toughness (K1c) decreases \u2014 making toughness at low temperature a critical material requirement for wind turbine ring gears. 42CrMo properly heat-treated to 250\u2013350 HB provides adequate fracture toughness at \u221230\u00b0C for wind turbine service, where simpler carbon steels (C45) may be at risk of brittle fracture initiation at the tooth root under high load transients in cold weather.<\/p>\n<\/div>\n

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High Contact Fatigue Strength<\/h3>\n

Wind turbine ring gears experience over 10\u2079 tooth contact cycles in their 20-year design life at a 3 MW rated power site running at average capacity factor of 35%. The contact stress on the tooth surface must remain below the material’s endurance limit for pitting fatigue across this very high cycle count. 42CrMo at 280\u2013320 HB provides a contact fatigue endurance limit approximately 25\u201335% higher than C45 at the same hardness range, directly increasing the ring gear’s pitting-free service life.<\/p>\n<\/div>\n

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DIN 3962 Class 7 \u2014 Wind Turbine Standard<\/h3>\n

DIN 3962 (now superseded by DIN ISO 1328 but still specified in many wind turbine gearbox drawings) Class 7 is the minimum accuracy standard for wind turbine main gearbox ring gears. It corresponds approximately to AGMA Class 9 or DIN ISO 1328 Class 7. At this accuracy level, the transmission error of the ring gear pair is low enough that it does not generate significant acoustic emission at the blade-passing frequency harmonics that wind turbine gearboxes are characteristically sensitive to.<\/p>\n<\/div>\n<\/div>\n

<\/p>\n

Applications<\/h2>\n

\"Ever-Power<\/p>\n

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\ufe0f<\/div>\n

Wind Turbine Main Gearbox<\/h3>\n

42CrMo ring gears Mn=4\u20138 in the planetary stages of wind turbine main gearboxes for 0.5\u20135 MW turbines. The first-stage planetary ring gear carries the full low-speed rotor torque \u2014 the highest torque point in the wind turbine drivetrain. DIN 3962 Class 7 and tooth grinding to Ra 0.6 are mandatory for the 20-year design life target under variable wind loading.<\/p>\n<\/div>\n

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\u2699\ufe0f<\/div>\n

Pitch and Yaw Actuator Drives<\/h3>\n

42CrMo or carbon steel ring gears Mn=2\u20135 in the pitch actuator planetary drives that rotate each turbine blade to control the angle of attack, and in the yaw drive planetary gearboxes that rotate the nacelle to track wind direction. Both drives cycle continuously throughout the turbine’s operating life and are exposed to outdoor temperature and corrosion conditions.<\/p>\n<\/div>\n

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\ufe0f<\/div>\n

Heavy Industrial Gearboxes<\/h3>\n

Large-module ring gears (Mn=6\u201326) for industrial planetary gearboxes in rolling mill drives, cement plant kiln drives, mining equipment drives, and ship propulsion planetary gearboxes. The same 42CrMo material and DIN Class 4\u20138 accuracy capability that serves wind turbines covers the full range of large-module heavy industrial ring gears.<\/p>\n<\/div>\n

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Marine Propulsion<\/h3>\n

Alloy steel ring gears Mn=4\u201310 in marine reduction gearbox planetary stages. Marine ring gears share the wind turbine ring gear’s requirement for high toughness, adequate hardenability, and resistance to corrosive saltwater atmosphere. 42CrMo with appropriate surface treatment or CrNiMo stainless-clad variants are specified for offshore vessel gearboxes.<\/p>\n<\/div>\n

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<\/div>\n

Power Generation<\/h3>\n

Large ring gears in hydroelectric generator planetary stages, tidal power generator gearboxes, and large diesel generator sets. Power generation ring gears share the wind turbine requirement for long service intervals (5,000\u201320,000 hours between overhauls) driven by the high cost of unplanned power generation outages.<\/p>\n<\/div>\n

\n
\ufe0f<\/div>\n

Oil and Gas Equipment<\/h3>\n

Alloy or stainless steel ring gears Mn=4\u201320 in oil and gas downhole drilling tool planetary stages, topside pump planetary drives, and wellhead control valve planetary actuators. The 2,500 mm OD capability covers the largest slewing ring gears used in offshore drilling equipment and crane systems.<\/p>\n<\/div>\n<\/div>\n

<\/p>\n

Frequently Asked Questions<\/h2>\n
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What is the delivery time for wind turbine ring gears?<\/p>\n

For standard configurations in stock: 5\u201310 days. For custom ring gears (non-standard module, specific tooth count, or special heat treatment not in standard production): 15\u201320 days depending on quantity. Wind turbine ring gears at large module (Mn=6\u201310) and OD (500\u20132,500 mm) require significant forging, rough machining, heat treatment, and final grinding lead time \u2014 the 15\u201320 day delivery window assumes the material is available in stock. For very large ring gears requiring forging from billet, the lead time will be longer and is confirmed at the quotation stage.<\/p>\n<\/div>\n

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Why is tooth grinding required for wind turbine ring gears?<\/p>\n

Heat treatment (quenching and tempering, or induction hardening) introduces thermal distortion in the ring gear blank \u2014 the tooth profile deforms slightly during the quench as the surface and core cool at different rates. For wind turbine ring gears at DIN 3962 Class 7, the distortion from heat treatment exceeds the allowed tolerance \u2014 the gear must be tooth-ground after heat treatment to correct the profile back to the dimensional tolerance. Tooth grinding achieves Ra 0.6 tooth surface finish (vs Ra 3.2 for shaped or milled), which directly reduces the micro-pitting risk at the tooth contact zone over the 20-year service life.<\/p>\n<\/div>\n

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Are free samples available for wind turbine ring gears?<\/p>\n

Yes \u2014 Korea Ever-Power can offer free samples for wind turbine ring gears, with the freight cost paid by the customer. For large ring gears (above approximately 300 mm OD), the “sample” is typically a smaller-format sample ring gear demonstrating the material, tooth profile accuracy, heat treatment, and surface treatment \u2014 not necessarily at full size, unless full-size sampling is requested. For standard module combinations in stock, the sample demonstrates the production standard before the full production order is placed. Contact Korea Ever-Power with the specification to confirm what form the sample will take for your application.<\/p>\n<\/div>\n

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What are the payment terms for wind turbine ring gear orders?<\/p>\n

Payment terms depend on order value: for orders \u2264 USD 1,000, 100% payment in advance is required. For orders > USD 1,000, the standard terms are 30% T\/T in advance (to cover material procurement and production set-up) and the balance (70%) before shipment (after production completion and final inspection). For very large wind turbine ring gear orders where the order value requires additional payment security, Letter of Credit (L\/C) payment is also available \u2014 contact Korea Ever-Power to discuss at the quotation stage. Contact our team<\/a> for a quotation.<\/p>\n<\/div>\n<\/div>\n

<\/p>\n

Customer Reviews<\/h2>\n
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“We supply wind turbine gearboxes for a 2 MW coastal turbine programme and source 42CrMo ring gears Mn=6, Z=109 from Korea Ever-Power. DIN 3962 Class 7 confirmed on our gear measurement machine \u2014 profile deviation within tolerance on all teeth. Tooth surface Ra 0.6 measured by stylus profilometer. Delivery 16 days on our last production order; within the 15\u201320 day range confirmed at quotation.”<\/p>\n

Kim Dong-jun<\/strong> \u00a0|\u00a0 Wind Turbine Gearbox Engineer, Incheon Renewable Energy Systems Co. \u00a0\u00b7\u00a0 Q1 2026<\/em><\/p>\n<\/div>\n

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“We manufacture yaw drive planetary gearboxes for offshore wind turbines and use alloy steel ring gears<\/a> Mn=4 from Korea Ever-Power. The \u00b10.005 mm OD tolerance is confirmed at our incoming CMM \u2014 the ring gear interference fit in the gearbox housing is tight and the OD tolerance determines whether the fit is within specification. Free sample confirmed the OD tolerance before we committed the full production order.”<\/p>\n

Lee Sang-hyeon<\/strong> \u00a0|\u00a0 Offshore Wind Gearbox Engineer, Gyeonggi Offshore Wind Systems Co. \u00a0\u00b7\u00a0 Q4 2025<\/em><\/p>\n<\/div>\n

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“We supply large industrial planetary gearboxes for cement plant kiln drives \u2014 ring gears Mn=14, OD 1,200 mm. Korea Ever-Power confirmed their tooth grinding capability to OD 2,500 mm and max module 45 mm \u2014 covering our size specification with margin. 42CrMo material certificate and Q&T heat treatment report included with delivery. 30% T\/T advance payment, balance before shipment \u2014 standard terms for our procurement process.”<\/p>\n

Park Sang-woo<\/strong> \u00a0|\u00a0 Heavy Industrial Gearbox Engineer, Busan Industrial Drive Systems Co. \u00a0\u00b7\u00a0 Q2 2026<\/em><\/p>\n<\/div>\n

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“We distribute wind turbine gearbox repair ring gears for the Korean and Southeast Asian wind turbine aftermarket. Korea Ever-Power’s 5\u201310 day stock delivery on standard Mn=6 configurations means we can respond to urgent gearbox failure repairs without the 15\u201320 day production wait. The 42CrMo material and DIN 3962 Class 7 accuracy match the OEM specification \u2014 accepted at all our wind turbine operator customers’ maintenance incoming inspections.”<\/p>\n

Choi Hyeon-jun<\/strong> \u00a0|\u00a0 Wind Turbine Parts Distribution Manager, Daejeon Wind Energy Supply Co. \u00a0\u00b7\u00a0 Q3 2025<\/em><\/p>\n<\/div>\n

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“We manufacture marine vessel planetary reduction gearboxes. Korea Ever-Power’s tooth grinding capability to 2,500 mm OD and module 45 mm covers our largest marine ring gear specification. 17CrNiMo5 alloy steel substituted for 42CrMo at our request \u2014 Korea Ever-Power confirmed the material availability and confirmed the equivalent DIN Class 4 accuracy at the larger module. All material and mechanical test documentation included with delivery for our classification society records.”<\/p>\n

Yoon Jae-bum<\/strong> \u00a0|\u00a0 Marine Propulsion Gearbox Engineer, Ulsan Marine Drive Systems Co. \u00a0\u00b7\u00a0 Q1 2025<\/em><\/p>\n<\/div>\n<\/div>\n

<\/p>\n

Related Products<\/h2>\n
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\n\"Planetary
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Full ring gear range: wind turbine, planetary, cement mixer, flywheel, aerospace, automotive, and more \u2014 all sizes from Mn=0.15 to Mn=45.<\/p>\n

Browse Ring Gears \u2192<\/a><\/p>\n<\/div>\n<\/div>\n


\n\"Industrial
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Helical Gears<\/h3>\n

Large-module industrial helical gears for the high-speed stages of wind turbine gearboxes \u2014 the parallel-shaft complement to wind turbine planetary ring gear stages.<\/p>\n

Browse Helical Gears \u2192<\/a><\/p>\n<\/div>\n<\/div>\n


\n\"Forging
\n<\/a><\/p>\n
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Ingranaggi conici<\/h3>\n

Forged bevel gears for right-angle drives in wind turbine yaw and pitch mechanisms \u2014 the intersecting-shaft complement to wind turbine planetary ring gear assemblies.<\/p>\n

Browse Bevel Gears \u2192<\/a><\/p>\n<\/div>\n<\/div>\n


\n\"Forging
\n<\/a><\/p>\n
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Spur Gears<\/h3>\n

Large-module forging spur gears for sun and planet gear roles in wind turbine planetary stages \u2014 matched 42CrMo material and DIN accuracy for complete planetary gear sets.<\/p>\n

Browse Spur Gears \u2192<\/a><\/p>\n<\/div>\n<\/div>\n<\/div>\n

\n

Request a Quotation for Wind Turbine Ring Gears<\/h3>\n

42CrMo standard; module 1.0\u201345 mm; OD to 2,500 mm; DIN Class 4\u20137 by tooth grinding. Free samples. Delivery 5\u201310 days (stock) \/ 15\u201320 days (custom). 30% T\/T advance > USD 1,000.<\/p>\n

Get a Quote Now<\/a><\/p>\n<\/div>\n<\/div>","protected":false},"excerpt":{"rendered":"

Korea Ever-Power ring gears for wind turbines: 42CrMo alloy steel; involute; 20\u00b0 pressure angle; DIN 3962 Class 7; standard Mn=6, Z=109, \u03b2=0\u00b0, X=\u22120.25. Process: forging \u2192 hobbing \u2192 tooth grinding. OD tolerance \u00b10.005 mm. DIN Class 4 by tooth grinding; Ra 0.6. Internal gear capability to OD 2,500 mm; module to 45 mm (grinding). Materials: carbon steel (SAE1020, SAE1045), alloy steel (20CrMnTi, 42CrMo, 17CrNiMo5), brass\/bronze.<\/p>","protected":false},"featured_media":1612,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":""},"product_brand":[],"product_cat":[4560],"product_tag":[],"class_list":["post-1611","product","type-product","status-publish","has-post-thumbnail","product_cat-ring-gear","pa_editor-cxm","first","instock","product-type-simple"],"_links":{"self":[{"href":"https:\/\/gearrack.top\/it\/wp-json\/wp\/v2\/product\/1611","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/gearrack.top\/it\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/gearrack.top\/it\/wp-json\/wp\/v2\/types\/product"}],"replies":[{"embeddable":true,"href":"https:\/\/gearrack.top\/it\/wp-json\/wp\/v2\/comments?post=1611"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/gearrack.top\/it\/wp-json\/wp\/v2\/media\/1612"}],"wp:attachment":[{"href":"https:\/\/gearrack.top\/it\/wp-json\/wp\/v2\/media?parent=1611"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/gearrack.top\/it\/wp-json\/wp\/v2\/product_brand?post=1611"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/gearrack.top\/it\/wp-json\/wp\/v2\/product_cat?post=1611"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/gearrack.top\/it\/wp-json\/wp\/v2\/product_tag?post=1611"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}