Module 4 of 10 180m 180 min 3 exam Qs 3 exam questions covered
Gears & Gearbox Systems
Gear reducer function, right-angle power transmission, backlash measurement, and gearbox maintenance procedures.
- Identify gear types and their power transmission characteristics
- Measure and adjust gear backlash
- Perform gearbox maintenance including oil changes and inspections
Lesson 1
Gear Types & Reducer Functions
Common Gear Types
| Gear Type | Shaft Orientation | Characteristics |
|---|---|---|
| Spur | Parallel | Simple, noisy at high speed, no axial thrust |
| Helical | Parallel | Quieter, smoother, creates axial thrust |
| Bevel | Intersecting (90 degrees) | Right-angle power transmission |
| Worm | Right angle (non-intersecting) | High ratio reduction, self-locking |
| Herringbone | Parallel | Cancels axial thrust of helical |
Gear Reducer Function
A gear reducer (gearbox) reduces speed and increases torque between the prime mover (motor) and the driven equipment. The gear ratio determines the speed reduction:
Speed
Decreases by Gear Ratio
Torque
Increases by Gear Ratio
Power
Remains Constant (Minus Losses)
Worm Gear Self-Locking
Worm gear reducers with lead angles below approximately 5 degrees are self-locking - the output cannot drive the input. This makes them ideal for hoisting and lifting applications where the load must hold position when the motor stops.
Key Takeaway
Gear reducers decrease speed and increase torque proportionally. Spur gears are simple but noisy; helical gears are quieter but create axial thrust. Worm gears are self-locking below 5 degrees lead angle - ideal for hoisting.