Gear Systems
Gear
A toothed wheel that meshes with another to transmit motion or change speed/direction.
Key Components of Gear Systems
- Gear Teeth: Interlocking projections that engage with other gears.
- Gear Shaft: The axis around which the gear rotates.
- Pitch Circle: The imaginary circle where gear teeth engage which determines gear size and spacing.
- Module: The ratio of the pitch diameter to the number of teeth.
- Pressure Angle: The angle between the gear tooth profile and the gear tangent: affects smoothness and strength of transmission.
The module is a critical parameter in gear design, ensuring compatibility between gears.
- A high gear ratio (e.g. 3:1) = increased torque, reduced speed.
- A low gear ratio (e.g. 1:3) = increased speed, reduced torque.
Types of Gear Systems
Spur Gears
Spur Gear
A toothed gear with teeth that project parallel to the gear’s axis, used to transmit motion between parallel shafts.
- Use: Transmit motion between parallel shafts.
- Example: Clocks, conveyor belts.
Spur gears are the most common type of gear due to their simplicity and efficiency.
Bevel Gears
Bevel Gear
A pair of toothed rotating gears that transfer power between intersecting shafts, usually at a 90° angle.
- Use: Transmit motion between intersecting shafts (usually at 90 degrees).
- Example: Differentials in automobiles.
Bevel gears are essential for changing the direction of motion in machinery.
Rack and Pinion
Rack & Pinion
A mechanical system where a toothed bar (rack) engages with a circular gear (pinion) to convert rotary motion into linear motion.
- Use: Convert rotary motion to linear motion.
- Example: Steering systems in cars.
Rack and pinion systems are ideal for applications requiring precise linear movement.
