Medical Double Helical Gear – M0.15-M2.0, Metal, AGMA 13

A herringbone gear is a specific type of double helical gear — a side-by-side (not face-to-face) combination of two helical gears of opposite hands on a common blank. Viewed from the top of each tooth, the helical grooves form the letter V; many V-grooves together produce the herringbone pattern that gives this gear form its name. Unlike single helical gears, herringbone gears do not produce an additional axial thrust load on the shaft — the axial forces from the two tooth sets cancel each other. For medical devices and instruments, this thrust-free operation simplifies the bearing and housing arrangement in compact gear trains where minimising component count and size is essential.

Korea Ever-Power produces medical double helical gears from Φ3 mm upward in metal, steel, stainless steel, copper, brass, and alloy grades per customer specification. The standard Φ12 mm example at module M0.15–M2.0 is representative of the size range used in surgical robot wrist drives, infusion pump gear trains, and laboratory instrument actuators. Meshing grades from ISO 6 through AGMA 13 and DIN 5–6 cover the precision range demanded by medical device OEM quality systems.

No Axial Thrust

The herringbone form eliminates axial load on the shaft bearing. In compact medical device gear trains where the shaft support is a small precision bushing or a miniature ball bearing, the elimination of axial thrust directly extends bearing life and simplifies the mechanism design.

Smooth, Quiet Operation

Medical environments are acoustically sensitive — gear noise in a surgical theatre, imaging suite, or ward disturbs clinical staff and patients. The helical tooth form's progressive engagement, combined with the double-helical form's high contact ratio, produces the quietest gear mesh among all external gear configurations at the same pitch diameter.

High Precision (AGMA 13)

AGMA 13 (≈ DIN 5) is the highest practical accuracy for machined metal gears in the M0.15–M2.0 size range. At this accuracy, transmission error is minimised — important in surgical robots where positional error at the gear stage translates directly to end-effector position error at the patient.

High Precision Internal Gear

Highly precise internal (ring) gear variants are available. Internal herringbone gears allow compact epicyclic gear stage designs in medical robots and motorised surgical instruments where the planetary arrangement delivers high reduction ratio in a very small axial length.

Surgical Robots

Wrist joint drives in surgical robot arms — Φ12 mm stainless steel or alloy double helical gears at AGMA 13. The combination of non-magnetic stainless, high accuracy, zero axial thrust, and autoclave compatibility meets all primary surgical robot gear specifications.

Infusion Pumps

Peristaltic and syringe pump drive gear trains — small-diameter stainless or POM herringbone gears in sealed pump mechanisms. The quiet operation and zero-thrust property suit the compact, sealed drive where external lubrication is not possible.

Diagnostic Imaging

Gantry rotation drives in CT scanners and C-arm positioning systems. Non-magnetic stainless steel double helical gears for MRI gantry drives where magnetic field distortion must be minimised. The quiet operation reduces patient anxiety during scanning.

Laboratory Automation

Liquid handling robot drives, microplate handler actuators, and centrifuge speed change mechanisms — alloy or stainless herringbone gears at M0.15–M2.0. The high meshing grade accuracy (AGMA 13) meets the positional precision requirement of laboratory automation systems.

Rehabilitation Equipment

Motorised rehabilitation device drives — powered exoskeletons, motorised treadmills, and assisted movement devices. Alloy steel herringbone gears at moderate accuracy grades provide the load capacity and quiet operation required in physiotherapy environments.

Military and Aircraft

Precision instrument and control mechanism drives in military electronics and aircraft systems — the same herringbone gear form and AGMA 13 accuracy grade used in medical devices meets the precision, quiet operation, and material requirements of avionics and military instrument gear trains.

How long does it take to produce a sample for a medical double helical gear?

For simple configurations — standard module, standard bore, straightforward material — a sample can be completed within one week. More complex configurations (very fine pitch at M0.15–M0.2, non-standard bore profiles, specialised alloy materials requiring procurement) may require additional time. Contact Korea Ever-Power with the specific drawing or specification and we will confirm the sample lead time for that configuration before the sample order is placed.

Can Korea Ever-Power supply internal (ring) herringbone gears for planetary drive stages?

Yes — highly precise internal herringbone gears are available. Internal double helical ring gears are used in planetary epicyclic gear stages where the double helical form provides the same thrust-free and high-contact-ratio advantages as external herringbone gears. The internal herringbone is machined by shaping (not hobbing, since hobbing cannot produce an internal gear) to the required accuracy grade. Provide the drawing including the ring gear OD, bore (pitch cylinder), tooth count, module, helix angle, and accuracy grade.

Is ODM service available for medical device gear design?

Yes — Korea Ever-Power's ODM service covers gear design for medical device applications where the customer has a functional requirement (load, speed, life cycle, accuracy, material) but no finished gear drawing. Our engineering team designs the gear geometry, proposes the material and accuracy grade, and produces the drawing for customer approval before production. This service is particularly valuable for surgical robot wrist gear design where the gear must fit within a constrained envelope and meet both accuracy and sterilisability requirements simultaneously.

Can other products be shipped on the same DHL or UPS shipment to save freight?

Yes — Korea Ever-Power is willing to help customers consolidate shipments to save express freight charges. If you have other products from Korea Ever-Power or from other China suppliers that need to ship at the same time, contact our team to discuss consolidation options. For medical device OEM programmes with multiple component types, consolidated shipment reduces the total express freight cost per unit compared with separate shipment of each component type.

What detailed photos or videos can be provided for product verification?

For stock items, Korea Ever-Power provides detailed photos or videos immediately upon request so customers can visually check the product before shipment. For custom-produced medical double helical gears, pre-shipment photos showing the gear and the dimensional inspection report are provided as standard before the balance payment is requested. If video of the gear is required — for example, showing the tooth form, the central groove, or the bore — this can be arranged. Contact our team with the specific verification requirement and we will confirm what can be provided.

"We develop surgical robot wrist drives and specified Φ12 mm SS316L double helical gears at AGMA 13 from Korea Ever-Power. The sample was ready within 7 days. Meshing grade confirmed at our CMM incoming check. The autoclave sterilisation test (134°C, 50 cycles) showed no dimensional change exceeding our measurement uncertainty. TS16949 certificate accepted at our supplier quality audit."

Kim Seo-yeon  |  Mechatronics Engineer, Incheon Surgical Robotics Co.  ·  Q1 2026

"We design infusion pumps and used Korea Ever-Power's ODM service to design the pump drive herringbone gear — we had the torque and speed specification but no gear drawing. Their team produced the M0.5 gear geometry, confirmed the stainless material selection, and delivered the sample within the quoted one-week lead time. The gear mesh noise in our acoustic test chamber is below our target limit."

Lee Hyun-joo  |  Pump Mechanism Designer, Seoul Medical Devices Co.  ·  Q4 2025

"We manufacture MRI-compatible gantry positioning drives. Korea Ever-Power produced M1.0 SS304 medical double helical gears confirmed non-magnetic by Feritscope measurement at our incoming inspection. The vacuum tray packaging prevented moisture absorption and bore dimension change during the 3-week express transit from China. DHL delivery was within the quoted 5 working days."

Park Byeong-ho  |  Imaging Systems Component Engineer, Busan Medical Imaging Systems  ·  Q2 2026

"We supply rehabilitation exoskeleton drives and consolidated three gear component types from Korea Ever-Power into a single DHL shipment — medical double helical gears, stainless spur gears, and alloy steel bevel gears. Ever-Power coordinated the packing and managed the consolidated shipment as offered. Express freight saving was approximately 35% vs three separate shipments."

Choi Min-young  |  Component Procurement Manager, Gyeonggi Rehabilitation Technology  ·  Q3 2025

"We import medical herringbone gears for laboratory automation distributors. Korea Ever-Power provided stock photos and video of the M0.8 SS304 gears within 24 hours of our enquiry — our customer needed to verify the central groove width before approving the order. ISO 9001:2008 and TS16949 certificates are accepted at our customer's incoming inspection without additional documentation."

Yoon Jae-seon  |  Medical Component Import Manager, Seoul Scientific Instruments Trading  ·  Q1 2025