Couronne dentée de volant moteur pour tracteur – C45/42CrMo, cémentée

The flywheel ring gear for agricultural tractor parts is a critical engine starting component — it sits on the engine flywheel and engages with the pinion of the starter motor to crank the engine upon starting. The ring gear transfers starting torque from the starter motor to the engine crankshaft. Every time the tractor engine is started, the starter motor pinion engages the flywheel ring gear's teeth, accelerates the engine from rest to cranking speed (approximately 150–250 rpm), and disengages once the engine fires. Over the tractor's service life — typically 10,000–15,000 engine hours for an agricultural tractor — the flywheel ring gear may experience 50,000–100,000 start engagement cycles with each cycle producing a significant impact load on the engagement teeth.

Korea Ever-Power's flywheel ring gears have high bearing capacity and are durable in practical applications. One-stop service from raw material organisation to processing and assembly. Professional engineering team and strict quality control. Free samples. OEM service. Delivery 7 days (standard) or 30 days (custom per quantity).

Impact Tooth Strength

Every engine start produces an impact load on the ring gear teeth — the starter motor pinion, spinning at 1,000–3,000 rpm, engages the stationary flywheel ring gear teeth. The engagement impact imposes a bending stress at the tooth root that is several times the steady-state bending stress during normal starter cranking. The ring gear material's core toughness (resistance to tooth root crack initiation under impact) is the critical property for flywheel ring gear service life. Carburised case with tough core (20CrMnTi / 42CrMo carburised) provides the optimal combination of hard case and tough core for this duty.

Thermal Expansion and Press Fit

Flywheel ring gears are shrink-fitted onto the flywheel — heated to expand, slid over the flywheel OD, and allowed to cool into interference fit. The ring gear's bore tolerance must be precise enough to achieve the correct interference fit after cooling (adequate retention force) without excessive stress in the ring gear body. Korea Ever-Power controls the bore diameter to the tolerance specified on the customer's drawing and confirms the fit calculation for the specified interference at the design stage.

Tooth Lead-In Chamfer

Modern flywheel ring gears have a tooth lead-in chamfer on one face to guide the starter motor pinion into mesh smoothly and reduce the impact load on the tooth tips during engagement. The chamfer angle and length are critical for smooth engagement — too shallow and it does not guide; too deep and it reduces the tooth face width and load capacity. Korea Ever-Power machines the lead-in chamfer to the customer's drawing specification as part of the standard production process.

High Bearing Capacity

The flywheel ring gear's high bearing capacity comes from the combination of high case hardness (58–62 HRC for carburised grades), adequate case depth (0.8–1.5 mm depending on module), tough core (200–280 HB), and controlled tooth profile accuracy. Korea Ever-Power's production equipment — NC gear hobbing, NC gear grinding, and NC gear shaving — produces the tooth geometry and surface quality that maximises the bearing capacity per unit face width for the agricultural tractor's start cycle duty.

Agricultural Tractors

20CrMnTi carburised flywheel ring gears for compact utility tractors through large row-crop tractors. Agricultural tractors start frequently — field operators may start and stop the engine multiple times per work hour during headland turns, implement changes, and fuel stops. High start-cycle endurance is the primary requirement. OEM and aftermarket replacement production available.

Passenger Cars and Trucks

40Cr or C45 flywheel ring gears for petrol and diesel passenger cars and light-to-heavy trucks. Passenger car start cycles are moderate — typically 3–10 starts per day, 5,000 starts per year. The flywheel ring gear's service life for a passenger car is typically the vehicle's lifetime — replacement is only required after impact damage or corrosion failure, not routine wear.

Earth Moving Equipment

42CrMo carburised flywheel ring gears for excavator, bulldozer, and grader diesel engine starting. Earth moving equipment engines are large-displacement, high-compression diesels requiring significant starter motor cranking torque — the flywheel ring gear bears higher starting impact loads than automotive flywheel ring gears at the same start cycle frequency.

Marine Engines

42CrMo stainless-clad or SS-alternative flywheel ring gears for marine diesel engine starting on commercial fishing vessels, workboats, and inland waterway vessels. Marine engines start less frequently than automotive but operate in a corrosive saltwater environment — stainless steel or SS-adjacent material options are considered for marine flywheel ring gears.

Lawn Mowers and Small Engines

C45 or 40Cr flywheel ring gears for petrol-engine riding lawn mowers, compact utility vehicles, and small-engine generator sets. Lower starting torque and moderate cycle count suit C45 material at lower cost. Seasonal start patterns typical for lawn mower engines suit good corrosion-resistant surface treatment to protect teeth during off-season storage.

Industrial and Power Generation

42CrMo flywheel ring gears for diesel generator sets and industrial stationary engines. Generator sets in standby mode may start infrequently — but each start is at full load from rest, imposing high impact on the ring gear. Generator set flywheel ring gears are safety-critical — failure to start during a power emergency is unacceptable — requiring the highest material and process specification.

How long is the delivery time for flywheel ring gears?

Standard flywheel ring gears (common sizes and specifications): 7 days. Custom flywheel ring gears (non-standard bore, special tooth count, or specific material not in standard production): 30 days per quantity. For urgent agricultural maintenance requirements — where the tractor engine cannot be started and the harvest season is time-critical — contact Korea Ever-Power with the specific ring gear specification and required delivery date. Korea Ever-Power will confirm whether accelerated production is possible for the specific configuration.

How do you ensure the quality of flywheel ring gears?

Quality documentation for flywheel ring gears includes raw material reports (chemical composition and mechanical properties of the steel billet, confirming the specified grade — C45, 40Cr, 20CrMnTi, or 42CrMo), metallographic examination reports (confirming the carburised case depth and microstructure after heat treatment — critical for the flywheel ring gear's impact resistance), and accuracy testing reports (confirming tooth profile, lead, and pitch accuracy against the drawing tolerance). These three documents together provide full traceability from steel billet to finished ring gear for every production batch.

What after-sales service does Korea Ever-Power provide?

Korea Ever-Power provides excellent after-sales service — customers can contact us anytime for quality issues that arise after delivery. If a flywheel ring gear fails prematurely, Korea Ever-Power requests the failed part and the quality documentation from the delivery batch, investigates the failure mode (tooth fracture, case spalling, bore slippage), and responds with a root cause analysis and corrective action. OEM customers receive priority after-sales response. The after-sales process is part of Korea Ever-Power's commitment to maintaining long-term customer relationships.

Can Korea Ever-Power produce flywheel ring gears as OEM parts?

Yes — Korea Ever-Power accepts OEM production for flywheel ring gears per the customer's requirements. OEM service includes production to the customer's drawing specification, part number marking on the ring gear and packaging, and quality documentation in the customer's format. Korea Ever-Power can also supply different gear types — spur gears, helical gears, herringbone gear wheels, and gear rings — from the same facility, allowing consolidation of multiple OEM gear part programmes to one supplier. Contact Korea Ever-Power with the OEM programme requirements to discuss the agreement terms. Contact our team to begin.

"We distribute aftermarket flywheel ring gears for Korean and imported tractor brands. Korea Ever-Power's 7-day delivery on standard configurations allows us to maintain minimal stock and respond quickly to dealers' urgent harvest-season demand. 20CrMnTi carburised specification confirmed by metallographic examination report included with each delivery batch. No warranty claims for tooth fracture in two years of distribution."

Kim Hyeong-cheol  |  Agricultural Parts Distribution Manager, Incheon Agricultural Supply Co.  ·  Q1 2026

"We manufacture tractor engines and source flywheel ring gears from Korea Ever-Power as OEM parts — our part number on the gear and packaging. The one-stop service covers forging through grinding and heat treatment from a single facility. Quality documents (material report, metallographic, accuracy test) match our OEM incoming inspection requirements exactly. 30-day delivery on our production batches, confirmed consistently over 12 months."

Lee Sang-jun  |  Engine Parts OEM Procurement Manager, Gyeonggi Tractor Engine Co.  ·  Q4 2025

"We supply flywheel ring gears for large diesel generator sets — 42CrMo carburised specification. Korea Ever-Power's after-sales response on one batch where we identified a case depth non-conformance at incoming metallographic: immediate investigation, root cause (heat treatment time deviation) identified, corrective action implemented, replacement batch produced and delivered in 10 days. Exactly the response we need from a supplier for safety-critical parts."

Park Jae-eon  |  Generator Set Engineering Manager, Busan Power Systems Co.  ·  Q2 2026

"We import flywheel ring gears for the Australian agricultural equipment aftermarket. Korea Ever-Power's free sample allowed our technical team to confirm the bore tolerance (critical for shrink-fit compatibility with our customer's flywheel specification) before committing to production. Customised packaging (individual protective wrap, quantity per carton per our logistics specification) provided at no extra cost. Sea freight to Sydney: 19 days."

Choi Dong-su  |  Agricultural Equipment Parts Import Manager, Daejeon Pacific Agricultural Supply Co.  ·  Q3 2025

"We manufacture marine workboat diesel engines and use 42CrMo flywheel ring gears from Korea Ever-Power. The professional engineering team confirmed the bore interference fit calculation for our flywheel material combination (ring gear steel on aluminium flywheel) — a non-standard shrink fit requiring careful thermal expansion calculation. The ring gear has been in service on our fleet vessels for 18 months without loosening or tooth wear issues."

Yoon Hyeon-tae  |  Marine Engine Engineering Manager, Ulsan Marine Power Systems Co.  ·  Q1 2025