Helical Gears
Helical gears are a type of cylindrical gear with angled teeth that form a helix around the gear axis. Unlike spur gears, where teeth are parallel to the axis, helical gears engage gradually, providing smoother and quieter operation.
Key Features of Helical Gears:
- Angled Teeth – Teeth are cut at an angle to the gear axis, allowing gradual engagement.
- Higher Load Capacity – The larger contact area enables these gears to handle higher loads.
- Smooth & Quiet Operation – Reduced noise and vibration compared to spur gears.
- Axial Thrust Force – Generates side thrust that must be countered with bearings.
- Parallel or Crossed Shafts:
- Parallel Shaft Helical Gears – Commonly used for power transmission in machines.
- Crossed Helical Gears (Screw Gears) – Used when shafts intersect at non-parallel angles.
Advantages:
✔ Higher efficiency and smoother motion than spur gears
✔ Reduced noise and vibration due to gradual tooth engagement
✔ Increased load-carrying capacity due to greater tooth contact
✔ Can transmit power between parallel or non-parallel shafts
Disadvantages:
✖ Generates axial thrust, requiring additional bearings for support
✖ More complex and expensive to manufacture than spur gears
✖ Efficiency slightly lower than spur gears due to sliding contact
Common Applications:
- Automotive Transmissions – Used in gearboxes for smoother gear shifting.
- Industrial Machinery – Found in conveyors, printing presses, and crushers.
- Marine & Aerospace – Used in propulsion systems for efficiency and durability.
- Power Generation – Applied in turbines and wind energy systems.