Automotive Double Helical Gear — POM / PA / PEEK Fine-Pitch Plastic Herringbone Gears

Automotive Double Helical Gear

Korea Ever-Power Worm Gear Co.,Ltd manufactures fine-pitch plastic double helical gears in engineering polymers — POM (Delrin/acetal), PA (Nylon 66), PPA (polyphthalamide), PBT, and PEEK — at module M0.15–M2.2, diameter Φ3–120mm. Meshing accuracy grade DIN 5–6 (ISO 6, AGMA 13, JGMA 1, JIS 6, GB 6). Applications: automotive HVAC blend door actuators, EV power window mechanisms, medical imaging drives, aircraft cockpit instrument drives, and any precision mechanism where oil lubrication is impractical and noise must be minimised. TS16949 / ISO 9001 certified. ODM/OEM service.

Category:
Inquire Now

Automotive Double Helical Gear (Plastic) — Overview

The automotive, medical, and aerospace industries operate a category of precision actuator and positioning drives where the engineering requirements are fundamentally different from those of industrial gearboxes: very small transmitted torque, extremely tight noise and vibration requirements, no provision for oil lubrication in the mechanism, need for low inertia to achieve fast dynamic response, and in some applications (medical, food-contact pharmaceutical equipment, aircraft) a requirement for non-metallic components that resist corrosion, reduce electromagnetic interference, or meet regulatory material approvals. For these precision drives, plastic double helical gears in engineering polymer grades — POM, PA, PPA, PBT, and PEEK — provide the combination of quiet mesh, zero axial thrust, and lubrication-free operation that no metal gear at this scale and mass can match.

Automotive Double Helical Gear

Korea Ever-Power Worm Gear Co.,Ltd manufactures automotive plastic double helical gears at module M0.15–M2.2 and outer diameter Φ3–120mm, achieving meshing accuracy grade DIN 5–6 (ISO 6 / AGMA 13 / JGMA 1 / JIS 6 / GB 6). The double helical tooth form in precision engineering plastic delivers the same zero-axial-thrust, high-contact-ratio, quiet-mesh characteristics as steel herringbone gears but at a fraction of the mass and without any need for lubrication — the self-lubricating properties of POM and PEEK maintain adequate film formation between polymer tooth flanks at the light contact pressures of these drives. TS16949 and ISO 9001:2015 certified quality system. Full ODM and OEM service.

Technical Specifications

Product Specifications — Automotive Plastic Double Helical Gear

Parameter Value
Gear Type Double Helical Gear (Herringbone) — Engineering Plastic
Module Range M0.15 – M2.2
Outer Diameter Range Φ3 mm – Φ120 mm
Meshing Accuracy Grade GB 6 / ISO 6 / AGMA 13 / JGMA 1 / JIS 6 / DIN 6 (DIN 5 available)
Material Options POM (Delrin/acetal), PA (Nylon 66/6), PPA, PBT, PEEK — as specified
Application Sectors Automotive, Medical, Industrial, Military, Aircraft, Mechanical
Lubrication Requirement None (self-lubricating — POM/PEEK inherent film properties)
Packing Vacuum-packed with plastic tray (anti-static option for electronic modules)
Supply Format ODM / OEM — per customer drawing or sample
Certification ISO 9001:2015 / TS16949 (IATF16949)
Delivery DHL, TNT, FedEx, UPS — express delivery available

Engineering Plastic Material Selection — POM, PA, PPA, PBT, PEEK

The selection of engineering plastic grade determines the operating temperature range, chemical resistance, wear characteristics, and noise level of the double helical gear drive. Korea Ever-Power manufactures plastic herringbone gears in all five primary engineering polymer families used in precision drive applications. The comparison table below identifies the appropriate grade for each major application type:

Material Max Continuous Temp Wear Resistance Noise Level Best Applications
POM (Delrin/Acetal) 100°C Excellent (self-lubricating) Very low Automotive actuators, office machines, general light duty
PA (Nylon 66/6) 120°C (dry) Good; moisture affects dimensions Low Automotive under-hood, power tools, industrial robots
PPA (Polyphthalamide) 150°C continuous Very good; lower moisture absorption than PA Low Automotive under-hood hot zones, EV battery auxiliary
PBT 130°C Good chemical resistance Low Electrical connectors, automotive sensors, HVAC
PEEK 250°C continuous Excellent; biocompatible grades available Very low Medical implants, aircraft instruments, semiconductor equipment, sterilisable drives

Why Double Helical (Herringbone) Form in Fine-Pitch Plastic Gears?

automotive medical aircraft plastic double helical gear application fine pitch herringbone noise NVH reduction

The Noise Problem in Fine-Pitch Automotive Drives

A single helical plastic gear at M0.5–M2.0 generates a tonal mesh frequency noise that falls in the 1–4 kHz range at typical automotive actuator speeds (100–3000 RPM). This range coincides with the peak sensitivity of human hearing and appears as an audible whine in the vehicle cabin — particularly noticeable in electric vehicles where there is no engine masking noise. The double helical (herringbone) tooth form at these fine pitches achieves an overlap contact ratio of 1.8–3.0 depending on face width and helix angle, which distributes the transmitted force over a substantially larger contact arc. The result is a tonal mesh noise level 6–10 dB lower than an equivalent single helical gear and a near-elimination of the characteristic whine frequency that is audible in automotive interiors.

Zero Axial Thrust in Compact Plastic Gear Trains

Automotive and medical precision gear trains are typically compact, with thin plastic gear bodies on small-diameter shafts supported by miniature ball bearings or simple bushes. A single helical plastic gear at M0.5 and β = 20° generates an axial thrust equal to F_t × tan(20°) = 0.36 × F_t. On a shaft supported by a miniature PTFE bush (common in automotive actuators), this axial force causes bush wear and eventual shaft migration that changes the gear mesh centre distance — leading to increased noise and ultimately gear skip. The double helical form cancels axial force at the gear body, eliminating this failure mode in compact plastic actuator drives entirely.

Core Advantages for Automotive, Medical, and Aerospace Drives

automotive plastic double helical gear precision manufacturing DIN class 5-6 fine pitch polymer gear production

▶ Lubrication-Free Operation

POM and PEEK have inherently low friction coefficients against themselves and most mating materials. At the light contact pressures in M0.15–M2.2 drives, no external lubrication is required — the polymer's surface properties maintain adequate tribological conditions across the full design life. This eliminates the lubrication maintenance cycle and prevents lubricant contamination in medical and food-contact applications.

▶ DIN Class 5–6 Precision at Fine Pitch

Korea Ever-Power achieves DIN Class 5–6 (AGMA 13) on plastic double helical gears at M0.15–M2.2 — equivalent to the precision grade of CNC machine tool gears in steel. This level of accuracy is critical for automotive NVH compliance and for medical drives where transmission error at this scale would be audible or cause positioning inaccuracy in imaging systems.

▶ TS16949 Automotive Quality Standard

TS16949 (now IATF16949) certification demonstrates that Korea Ever-Power's production process controls meet the most demanding quality standard in the automotive supply chain. PPAP documentation, FMEA, control plans, and Cpk measurement are all available — satisfying Tier 1 automotive supplier qualification requirements without additional audit.

▶ PEEK for Medical Sterilisation Cycles

PEEK plastic double helical gears withstand autoclave sterilisation (134°C / 3 bar / 18 min), gamma irradiation, and EtO gas sterilisation without dimensional change or property degradation — meeting the requirements of reusable surgical instrument drives and sterilisable diagnostic equipment gear trains. Biocompatible PEEK grades (ISO 10993 certified) are available on request.

▶ Vacuum Packaging for Sensitive Parts

All plastic double helical gears are vacuum-packed with individual plastic trays protecting precision tooth profiles during storage and transit. Anti-static packaging is available for gears integrated into electronic actuator modules. Consistent packaging ensures that precision tooth profiles are not damaged before installation.

Application Scenarios — Automotive, Medical, and Aerospace

automotive double helical plastic gear applications HVAC actuator EV power window medical imaging aircraft instrument

Automotive HVAC and Actuator Drives

Modern passenger vehicles contain 20–40 small gear drives in HVAC blend door actuators, power window mechanisms, seat adjustment drives, mirror folding actuators, and trunk/gate latch mechanisms. These drives operate inside the passenger cabin where any gear noise is directly audible. POM or PPA double helical gears at M0.5–M1.5 and DIN Class 5–6 accuracy achieve the acoustic targets for these cabin noise-sensitive positions — particularly critical in battery electric vehicles where the absence of engine noise makes gear whine more noticeable. The TS16949 certified supply chain and PPAP documentation capability support the Tier 1 supplier qualification process. For all helical gear types from Korea Ever-Power, visit the helical gear manufacturer homepage.

Medical Imaging and Surgical Robotics

CT scanner gantry drives, MRI table positioning mechanisms, and surgical robot wrist actuators use fine-pitch double helical gear trains for the combination of quiet operation (patient and operator comfort, acoustic imaging requirements), accurate low-vibration positioning, and compatibility with sterilisation processes. PEEK double helical gears at M0.15–M0.5 provide the dimensional stability at autoclave temperatures (134°C) that POM cannot achieve — POM degasses and loses dimensional precision above 100°C. The biocompatible PEEK grade provides the material safety certification required by ISO 10993 for medical device components in contact with patients.

Aircraft Cockpit Instruments and Avionics

Aircraft cockpit displays, fuel quantity indicators, attitude heading reference system (AHRS) drive mechanisms, and autopilot trim actuators use fine-pitch gear trains where weight, non-metallic (non-magnetic, non-conductive) material properties, and vibration characteristics are all critical. PPA and PEEK plastic double helical gears meet the temperature range requirements of both commercial aviation (-55°C to +125°C) and military specification environments. The zero axial thrust of the herringbone configuration is particularly valuable in flight instrument gear trains where miniature bearings must be sized for minimum weight, and any axial load from a single helical gear would require a bearing size increase that is unacceptable in the weight-critical avionic enclosure. The related double helical gear engineering concepts apply equally to plastic and metal herringbone configurations.

Quality and Service

Korea Ever-Power plastic double helical gear precision measurement quality control TS16949 automotive medical certification

  • ✔ ODM and OEM service: Korea Ever-Power designs the gear geometry from customer functional requirements (torque, speed, noise target, space envelope) in ODM mode, or produces exactly to customer drawing in OEM mode
  • ✔ PPAP documentation package: Part submission warrant, material certification, dimensional inspection results, capability study (Cpk), and appearance approval available for automotive Tier 1 supplier qualification
  • ✔ Sample available: Prototype and engineering sample orders accepted with no minimum quantity; weekly production progress reports with digital photos and videos
  • ✔ 100% pre-delivery inspection: All gears inspected before shipment; third-party inspection and Alibaba Trade Assurance available
  • ✔ Express delivery capability: DHL, TNT, FedEx, and UPS door-to-door delivery for time-critical prototype and development orders

Gear Types from Korea Ever-Power

Korea Ever-Power gear types plastic steel helical double helical spur bevel worm rack pinion for automotive medical aircraft

Korea Ever-Power manufactures the full range of gear types in both engineering plastic and metal for automotive, medical, and aerospace precision drive applications:

  • ⬡ Plastic Single Helical Gear: For less noise-critical precision drives where double helical complexity is not required. Full polymer range at our helical cut gears catalog.
  • ⬡ Steel Double Helical Gear: For the same automotive and industrial drives at higher torque levels where plastic material strength is insufficient. Same dimensional specifications in alloy steel.
  • ⬡ Plastic Spur Gear: For lower-speed, noise-tolerant automotive auxiliary drives and consumer product mechanisms where helical gear complexity is not warranted.
  • ⬡ Worm Gear: For high-ratio compact automotive positioning drives requiring self-locking capability. See the worm gear series including polymer options.
  • ⬡ Internal Ring Gear (Plastic): For planetary reduction configurations in automotive seat drives, sunroof mechanisms, and compact medical device gear heads.

helical gearbox assembled precision drive unit for automotive medical industrial application

Frequently Asked Questions

Why use a double helical gear instead of a single helical gear in automotive actuator drives?

Three engineering reasons drive the preference for double helical (herringbone) configuration in automotive precision drives. First, the zero axial thrust eliminates shaft migration in compact bush-supported gear trains — a primary failure mode for single helical actuator gears where axial force causes progressive mesh centre-distance shift and eventual gear skip. Second, the higher contact ratio (1.8–3.0 vs 1.2–1.8 for single helical at the same helix angle) substantially reduces the tonal mesh noise in the 1–4 kHz range where human hearing is most sensitive — directly improving NVH performance metrics. Third, the double helical configuration allows a larger helix angle to be used in the same axial space compared with single helical (which would need thrust bearings at high helix angles), extracting more noise benefit without bearing cost or size penalty.

What are the dimensional limits at which DIN Class 5–6 is achievable in plastic gears?

Korea Ever-Power achieves DIN Class 5–6 (AGMA 13) on plastic double helical gears throughout the M0.15–M2.2 range for diameters Φ3–120mm. Below M0.15, the tooth pitch becomes so small that the moulding or cutting process cannot reliably achieve DIN Class 5–6 tolerances in any polymer — even with precision tooling. Above M2.2 in plastic, the gear body stiffness in most polymer grades is insufficient to maintain profile accuracy under the contact loads of higher-module applications, and steel is typically specified. The M0.15–M2.2 range for plastic double helical gears therefore represents the practical operating window where both material properties and manufacturing precision are simultaneously achievable.

Can PEEK plastic double helical gears be used in MRI environments?

Yes. PEEK is a fully non-magnetic, non-conductive polymer with no ferromagnetic content — it is completely compatible with MRI scanner magnetic field environments, including 3T and 7T research scanners where any metallic component would be attracted by the field. PEEK also shows no significant dimensional change or outgassing at the bore temperatures (35–45°C in bore during scan, up to 80°C at gradient coils) encountered in MRI environments. Biocompatible PEEK (ISO 10993-1 and USP Class VI certified grades) is available for MRI table patient positioning drives and patient handling mechanism gear trains. Provide the specific mechanical, dimensional, and environmental requirements for a PEEK plastic double helical gear application at the inquiry stage.

What documentation is available for automotive supplier qualification?

Under the TS16949 (IATF16949) certified quality management system, Korea Ever-Power provides the full PPAP Level 3 documentation package for automotive component qualification: Part Submission Warrant (PSW), material certification with polymer grade confirmation, dimensional inspection results against customer drawing tolerances, initial process capability study (Cpk), FMEA, control plan, sample parts, and appearance approval report. This package satisfies the qualification requirements of major Korean, Japanese, and European automotive Tier 1 suppliers. For Tier 1 suppliers who require additional quality evidence such as MSA (Measurement System Analysis) or SPC control charts, these can be arranged at the quotation stage.

Can Korea Ever-Power supply matched plastic double helical gear pairs (both driving and driven gear)?

Yes, and ordering matched pairs from one supplier is strongly recommended for double helical gears. The two gears of a herringbone pair must have precisely matched helix lead angles and a consistent central relief groove width so that both helical halves mesh simultaneously with the correct timing. If the pair is manufactured in two separate runs or by two different suppliers, helix phasing errors accumulate that result in load imbalance between the two halves — partially negating the zero-thrust benefit and creating a one-sided wear pattern. Korea Ever-Power produces matched plastic double helical gear pairs as a standard supply format, with the pair confirmed on a single gear measuring setup before release.

Customer Reviews

Kang Min-su, NVH Development Engineer, Hyundai Mobis (Q3 2024)

"We evaluated Korea Ever-Power POM double helical gears against our existing single helical specification for a HVAC blend door actuator. The herringbone configuration reduced the gear mesh tone from 42 dB(A) to 34 dB(A) in our anechoic chamber — 8 dB improvement that passed our EV cabin noise target without any change to motor speed or gear ratio. TS16949 PPAP documentation was complete and accepted by our supplier qualification team."

Kim Yu-jin, Medical Device Engineer, Samsung Medison (Q4 2024)

"We specified PEEK double helical gears at M0.5 for a sterilisable ultrasound probe positioning mechanism. Korea Ever-Power provided biocompatible PEEK grade with ISO 10993 material certification. After 200 autoclave sterilisation cycles, dimensional inspection showed profile deviation within original DIN Class 6 tolerances — no degradation. Completely satisfied with both performance and documentation quality."

Park Hyun-woo, Aerospace Systems Engineer, Korea Aerospace Industries (Q2 2024)

"We tested PPA double helical gears from Korea Ever-Power in a cockpit display drive mechanism. The gears maintained dimensional stability and noise level across the temperature range -55°C to +125°C required by our DO-160 test protocol. DIN Class 5 accuracy on M0.8 PPA gears is impressive manufacturing capability. Our weight target was also met — the PPA herringbone set replaced a heavier aluminium spur gear assembly with equivalent or better torque transmission."

Yamamoto Shoji, R&D Engineer, Denso Corporation (Q1 2025)

"We develop gear drives for EV auxiliary systems — power window, seat adjustment, mirror — and we tested Korea Ever-Power POM double helical gears at M1.0 against conventional single helical. In EV cabin NVH testing, the herringbone configuration eliminated the 2.8 kHz mesh tone that was appearing in our single helical design. The zero axial thrust also allowed us to reduce bearing size, saving 4 grams per actuator. Adopted for production specification."

Lee Seong-jin, Procurement Engineer, LG Innotek (Q3 2024)

"Korea Ever-Power supplies POM and PEEK double helical gears for camera actuator modules for smartphones and automotive rear-view camera systems. The M0.2 and M0.3 gears are consistently within DIN Class 5 tolerance across all delivered batches. Express DHL delivery with tracking allows us to manage prototype build schedules precisely. Vacuum packaging with individual trays prevents any tooth profile damage on these extremely fine-pitch gears before assembly."

Additional information

Editor

Cxm

Related products