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Helical Gears
The Helical gears are similar to spur gears but have angled teeth. This helical tooth arrangement enables smoother
and quieter operation compared to spur gears. Helical gears are commonly used in applications where high torque
transmission and reduced noise are essential.
Here are some key details about helical gears:
• Tooth Profile: Helical gears have teeth with a helical or spiral shape. The helix angle refers to the angle between
the tooth’s helix line and the gear’s axis. The teeth are cut at an angle, resulting in a slanted or diagonal orientation.
The helical tooth profile allows for gradual engagement, which reduces noise and vibration compared to spur gears.
• Helix Direction: Helical gears can have either a right-hand helix or a left-hand helix. In a right-hand helix
gear, the helix spirals around the gear in a clockwise direction, while in a left-hand helix gear, the helix spirals
counterclockwise. The helix direction impacts the direction of the axial force exerted by the gear during operation.
• Axial Thrust: Due to the helical tooth arrangement, helical gears generate an axial thrust force along the gear’s
axis. This axial thrust can be both beneficial and challenging to manage. It helps to distribute the load between
gears but requires proper thrust bearings or other mechanisms to counteract the axial force.
• Meshing: Helical gears mesh in a similar manner to spur gears. The angled teeth of one gear engage with the
teeth of the mating gear, resulting in the transmission of rotational motion and torque. The gradual engagement
of helical gears reduces shock loads and allows for smoother power transmission.
• Power Transmission: Helical gears efficiently transmit power between parallel shafts. As the driving gear
rotates, its helical teeth gradually engage with the teeth of the driven gear, transmitting rotational motion and
torque. The angle of the helical teeth allows for a larger area of contact, enabling higher torque transmission
capacity compared to spur gears.
• Noise and Efficiency: Helical gears operate with less noise and vibration compared to spur gears. The gradual
engagement of helical teeth reduces the impact and noise during meshing. However, helical gears may experience
some axial thrust and slightly lower efficiency due to the additional friction caused by the helix angle.
Example: Consider a robotic arm that requires a high torque transmission with reduced noise and smooth
operation. Helical gears can be employed to achieve these requirements. The driving gear attached to the motor
has helical teeth with a right-hand helix, while the driven gear connected to the robotic arm also has helical teeth
with a right-hand helix.
As the motor-driven gear rotates, its helical teeth engage with the helical teeth of the driven gear. The gradual
meshing of the teeth ensures a smooth transfer of rotational motion and torque. The helical gears’ design reduces
noise and vibration, providing quieter operation in the robotic arm’s movement.
Helical gears find applications in various robotic systems, including gearboxes, robotic joints, and power
transmission mechanisms. They are particularly useful when high torque capacity, smooth operation, and reduced
noise are required, making them a preferred choice in many robotics applications.
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