Globoid Worm Gears

Globoid Worm Gear / Double enveloping Worm Gear

Simplistic
Structure

High Force
Transmission
Size reduction
possible

Introducing Globoid Worm Gear

Advantages of High Reduction Ratio and Simple Structure: Double-enveloping worm gears, known as globoid worm gears, offer a simple yet efficient solution to common issues such as heat generation and premature damage. Their high reduction ratio is a key advantage.
Unique Enveloping Design: As the name suggests, these gears have a distinctive structure that envelops and conforms to the curves of both the wheel and the shaft, providing a precise and secure fit.
Superior Performance and Stability: Among worm gears developed to date, globoid worm gears exhibit the highest performance-to-efficiency ratio and possess a stable structural design.

Cylindrical Worm Gear:

Cylindrical Worm Gear

High Ratio and Simple Structure: Cylindrical worm gears offer a high gear ratio and a straightforward, easy-to-produce structure.
Low Contact Points: However, they have fewer engagement points between gear teeth, which can lead to increased heat generation and a higher risk of premature breakage and damage.

Globoid Worm Gears

Globoid Worm Gear

High Gear Ratio and Complex Structure: Globoid worm gears provide a high gear ratio but have a seemingly simple yet challenging-to-produce structure.
Simultaneous Teeth Area Contact: Their structure involves more engagement and continuous sliding contact, resulting in efficient transmission and reduced heat generation.

Despite patent disclosure, only a few gear manufacturers have achieved successful implementation of globoid worm gears.
In the early 2000s, the American National Standards Institute (ANSI) established the only international standard for globoid worm gears through the American Gear Manufacturer Association (AGMA).

Globoid Worm Gear US Patent
(1925, S.I. Cone)

Globoid Worm Gear
International Standard
ANSI/AGMA 6135-A02

Designing these gears requires a complex algorithm based on geometrical theory to create a double-enveloping structure. Each tooth surface's unit area must be calculated and processed differently to ensure proper meshing from wheel to shaft.

EasternGear's double enveloping globoid worm gear is a modification of the globoid worm gear specified in AGMA 6135A-02, designed for simultaneous area contact.

ANSI/AGMA 6135-A02
Globoid Worm Gear (Double enveloping Gear)

Globoid Worm Gear Gearset central plane

EasternGear
Globoid Worm Gear 3D Design

Globoid Worm Gear Contact Image

Regular cylindrical worm gears have point or line contacts, whereas globoid worm gears have simultaneous area contact. This means multiple gear teeth are engaged and mesh at the same time for maximized force transmission.
When the gear shaft drive rotates, the contact area gradually expands, resulting in stable and consistent power transmission and increased efficiency and longevity of the product.

Comparison of Gear Contact Pattern Before Running-in