Gears for speed reduction
Gears are common in most motors and machines because they increase torque output through gear reduction and adjust the direction of rotation. However, there are different types of gears that can be integrated on machines to change its motor speed.
- Worm gears – are cost effective speed reducers with a setup designed so that the worm can change into a gear although the gear cannot change into a worm. Worm gear motors set new standards for reliability, cost effectiveness and efficiency with hollow shafts in the smallest sizes. The angles of the worm are shallow so that the gear is held in place due to friction. The most common application of Worm gear motors can be found on conveyor systems where the locking feature can act as a brake or an emergency stop.
- Spur gears – similar to Worm gear motors, this type of speed reducer is typically used for large speed reductions. Spur gears have straight teeth that are mounted in parallel on different shafts. The most common applications of spur gears can be found on washing machines, screwdrivers and windup alarm clocks. The most obvious drawback of spur gears is the noise that its produces due to impact of the gear tooth when engaging and colliding.
- Helical gears – compared to spur gears, helical gears operate quietly and smoothly because of the way the teeth interact. The teeth of the helical gear are cut at an angle to the face of the gear and when they start to engage, the contact is gradual. Contact starts at one end of the tooth and is maintained as the gear rotates into full engagement. The most common application of helical gears can be found in transmissions.
- Bevel gears – have teeth that are available in straight, spiral or hypoid shapes to change the direction of shaft rotation. Straight teeth have the same characteristics as the spur gears while spiral teeth operate in the same way as helical gears. Compared to straight teeth, spiral teeth produce less vibrations and noise. Bevel gears with the hypoid design have a shape that looks like a revolved hyperboloid instead of a conical shape.