Tvrdozubený špirálový prevod s bokom vysokorýchlostnej lokomotívy – DIN trieda 6 pre trakčné pohony

High Speed Train Locomotive Hard Tooth Flank Helical Gear — Overview

The traction gearbox of a high-speed railway vehicle faces engineering demands that no other rotating machinery category matches: pitchline velocities of 50–120 m/s, sustained full-load operation for hours at a stretch across millions of kilometres, vibration and noise constraints that directly affect passenger comfort scores, and safety certification requirements that mandate full material and process traceability on every gear. The high speed train hard tooth flank špirálové ozubené koleso from Korea Ever-Power Worm Gear Co.,Ltd is manufactured specifically for this duty, using 17CrNiMo6 alloy steel — the EN 10084 grade specified by European and Korean high-speed rail equipment manufacturers — through a complete forging, carburizing, and tooth-grinding sequence to DIN 3962 class 6 accuracy.

The reference configuration — Mn=4, Z=132, helix angle β=18°, pressure angle 20° — gives a pitch diameter of 528mm. This places it in the size range of a high-speed locomotive wheel gearbox primary gear or an EMU bogie gear, where the gear must transfer motor power to the axle at reduction ratios of 3:1 to 6:1 while running continuously at wheel speeds corresponding to 200–350 km/h line speed. The 18° helix angle is a deliberate choice for railway traction: large enough to provide significant overlap contact ratio improvement over spur gears (which are never used in traction gearboxes), but moderate enough that axial thrust loads remain manageable with the angular-contact bearings standard in railway axlebox assemblies. Korea Ever-Power's hard tooth flank helical gear production for railway applications includes full material traceability, dimensional inspection reports, and magnetic particle inspection certificates — all required for railway qualification programs.

Technické špecifikácie

Gear Basic Data — Reference Configuration

Manufacturing Capabilities — Internal Gears and Internal Splines

Manufacturing Capabilities — External Gears and External Splines

Why 17CrNiMo6 Is the Railway Standard for Traction Gear Steel

17CrNiMo6 (EN 10084) is a nickel-chromium-molybdenum case-hardening alloy used almost universally in European and Korean high-speed rail traction gearboxes. Its composition gives three properties that alternative materials cannot match simultaneously:

• ◈ Deep hardenability: Chromium (1.50–1.80%) and molybdenum (0.25–0.35%) together ensure that the carburized case transforms to martensite uniformly across the entire tooth flank surface of a 528mm pitch-diameter gear during quench — no soft spots in the case that would create localized pitting under the high contact stresses of traction service.
• ◈ Sub-zero toughness: Nickel content (1.40–1.70%) maintains fracture toughness down to approximately -40°C. Railway traction gearboxes are exposed to outdoor temperature extremes — trains running in Korean winter conditions at temperatures below -20°C require gear materials that do not become brittle at the tooth root under the shock loads from rail joints and switches.
• ◈ Thermal fatigue resistance: Molybdenum addition stabilizes the tempered martensite structure against softening during repeated thermal cycling from traction motor braking loads. This property is critical in traction gears that experience rapid load reversals during regenerative braking sequences at high speed.

Hard Tooth Flank vs Soft Tooth Flank — Railway Traction Gear Comparison

In railway traction gearboxes, the choice between hard tooth flank (carburized) and soft tooth flank (normalized or quenched-and-tempered) gears is not a cost trade-off — it is a service-life and safety requirement. The following comparison explains why hard tooth flank helical gears are mandatory for main traction duties in high-speed rail.

DIN Class 6 Precision and NVH for Passenger Rail

In passenger rail, gear noise affects passenger satisfaction scores and, in many countries, regulatory compliance with interior noise level requirements. The traction gearbox contributes a measurable fraction of total car interior noise at line speed — even after bogie and floor transmission paths are accounted for. DIN 3962 class 6 defines tight tolerance bands on tooth profile deviation, lead deviation, pitch accumulation, and total radial composite error. At this accuracy level, the transmission error excitation at the mesh frequency is suppressed to a point where gear mesh harmonic tones are typically 10–15 dB below the floor of the overall car interior noise spectrum at 300 km/h. Achieving DIN class 6 on a 528mm pitch diameter gear in carburized 17CrNiMo6 requires tooth grinding after heat treatment using a machine capable of maintaining the required positional accuracy on a large, heavy workpiece — Korea Ever-Power's German HÖFLER grinding machines are specified for exactly this type of precision large-gear production.

The Ra 0.6 tooth flank surface produced by finish grinding serves two functions beyond noise reduction: it maintains a stable lubricant film at high pitch-line velocities (EHL film theory requires a smooth surface to prevent breakdown at the asperity scale) and it produces the residual compressive stress pattern at the tooth surface that extends contact fatigue life. A hobbed surface at Ra 3.2 on the same gear body would see significantly higher contact stress concentration at surface asperities and substantially shorter pitting-free operating life.

Core Performance Advantages for Railway Traction Applications

Application Scenarios in Railway Traction Systems

High-Speed Locomotive Traction Gearbox

In a high-speed locomotive, each powered axle is driven by a traction motor through a single-stage or double-stage helical reduction gearbox mounted on the bogie frame. The primary gear in this arrangement takes the full motor output torque — typically 10,000–30,000 Nm per bogie depending on the locomotive class — and transmits it to the wheel axle at a speed ratio of 4:1 to 6:1. Pitch-line velocities in this service reach 80–120 m/s at 300+ km/h line speed. The Mn=4, Z=132, β=18° reference gear provides both the contact fatigue resistance and the low transmission error performance that this duty requires. For rail operators sourcing ozubené koleso so špirálovým rezom replacement components, Korea Ever-Power's reverse engineering service accepts worn gears from scheduled overhauls as the basis for a matched replacement order.

Electric Multiple Unit (EMU) Wheel Drive Gearboxes

EMU traction systems distribute power across multiple axles on a train set, with each motorized axle carrying a bogie-suspended gearbox. The gearbox in this configuration must accommodate bogie rotation relative to the train body (typically ±5°) through a flexible coupling, while the gear mesh itself operates under continuous cyclic loading from traction and braking. The 18° helix angle balances axial force against contact ratio: lower helix angles would reduce NVH performance; higher angles would generate axial forces that complicate the flexible coupling design. At β=18°, the resulting axial force is approximately 33% of the tangential force — a manageable level for the angular-contact bearings standard in EMU bogie gearbox construction. For technical consultation on špirálové ozubené koleso selection for rail traction applications, contact Korea Ever-Power through the výrobca špirálových ozubených kolies domovská stránka.

Urban Metro and Light Rail Traction Drives

Metro and LRT vehicles operate at lower maximum speeds than intercity HSR — typically 80–140 km/h — but experience more frequent acceleration and braking cycles than long-distance trains. The cumulative number of load cycles over a 30-year vehicle life is comparable to or exceeds that of a high-speed locomotive. Hard tooth flank gears in 17CrNiMo6 provide the fatigue life required for this long-cycle-count duty. The compact bogie design of metro vehicles also demands tight gear geometry — a DIN class 6 ground gear achieves the contact pattern quality that allows designers to operate at the tooth module and face width limits needed to fit within the bogie frame envelope.

Traceability, Documentation, and Quality System

Railway gear qualification programs require documentation depth that exceeds what is standard in general industrial supply chains. Korea Ever-Power's standard documentation package for railway traction gears includes:

• ✔ Raw material certificate: EN 10084 17CrNiMo6 mill heat number, full chemical analysis, mechanical property test results (yield strength, tensile strength, Charpy impact at -40°C), material identification linked to gear traceability code.
• ✔ Forging documentation: Forging press record, normalizing heat cycle parameters, ultrasonic testing result for internal discontinuities.
• ✔ Heat treatment record: Carburizing atmosphere cycle, quench date and temperature, tempering parameters, case depth measurement (per EN ISO 6508), case and core hardness per sampling plan.
• ✔ Gear measuring center report: Profile deviation, lead deviation, pitch accumulation, runout — all per DIN 3962 class 6 tolerance bands, measured by gear analyzer and reported numerically.
• ✔ Magnetic particle inspection certificate: 100% fluorescent MPI on all ground surfaces, operator identification, no-indication confirmation.
• ✔ Permanent traceability marking: Each gear bears a unique ID code linking all of the above records for lifetime maintenance audit purposes.

Typy výstroja z Kórey Ever-Power

Beyond railway traction gears, Korea Ever-Power manufactures a full range of gear types for industrial and transportation drive systems. If your application requires a different gear configuration or complementary components, the following are all within our manufacturing capability:

• ⬡ Čelné ozubené koleso: For lower-speed auxiliary drives on railway vehicles and rolling stock maintenance equipment where noise performance is less critical than in traction service.
• ⬡ Kužeľové ozubené koleso: Right-angle drives for ancillary systems — compressor drives, alternator drives, and bogie yaw damper mechanisms where shaft axes are non-parallel.
• ⬡ Šnekový prevod: Compact high-ratio drives for HVAC damper actuators and sliding door mechanisms on rail vehicles. The závitovkový prevod series covers the required reduction ratios with self-locking options.
• ⬡ Double Helical Gear: For high-power parallel-shaft industrial drives where eliminating axial thrust reduces bearing complexity. See the dvojité špirálové ozubené koleso series for specifications.
• ⬡ Vnútorný ozubený veniec: For epicyclic gearboxes and planetary reduction stages used in compact traction motor drives and rail vehicle auxiliary power units.

For railway maintenance workshops and industrial users requiring a complete enclosed drive rather than loose gears, assembled špirálová prevodovka reducer units are available. Contact Korea Ever-Power with your application details — vehicle type, motor torque, gear ratio, operating speed, and documentation requirements — for a technical proposal.

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