Different Types of Gears

Definition of Gear:-

Gear is very important part of any machine having cut teeth on its circumference which mesh with another toothed part or gear to transmit torque .

There are different types of gear are available in the market for a different application.
Below is the list of “Different types of gear”

1. Spur Gear
2. Bevel Gear
3. Worm Gear
4. Rack and Pinion
5. Helical Gear
6. Herringbone Gear
7. Internal and External Gear
8. Face Gear
9. Sprockets

Let’s see more about this gear:-

1.Spur Gear

  • Spur gear is the most common type of gear and they have straight teeth and all teeth are parallel to the axis of the wheel.
  • Spur gear is vary simple in design and needs very less maintenance.
  • Low cost of manufacturing and absence of end thrust
  • The major problem with this gear is high noise. Spur gear creates high noise when each time gear tooth engages with a tooth on other gear, the tooth collide and create high noise.
  • This gears are mainly used in the electric screwdriver, dancing monster, oscillating sprinkler, windup alarm clock, washing machine, and clothes dryer
Types-of-Gear-Spure-gear

2.Bevel Gear

  • Bevel gear is also called miter gear they have an equal number of teeth and shafts are positioned at the right angle.
  • Bevel gears are useful to change shaft rotation direction and they are mounted on shafts that are 90 degrees apart but can be designed to work at other angles as well.
  • The Teeth on bevel gears can be straight, spiral or hypoid.
  • Straight Bevel Gear:-
  • Most common and simplest type of bevel gear
  • Straight bevel gears have straight teeth like the spur gear
  • They share many similar properties of spur gears due to similar tooth shape.
  • The shaft must be perpendicular to each other, but they must also be in the same plane.
  • Spiral Bevel Gear:-
  • Spiral gear have Helical teeth( curved oblique teeth)
  • They can take more load as compare to straight bevel gears
    Rolling contact between gears is similar to that of straight bevel gears.
  • Provide a high level of control over the contact of teeth and design allows for certain mounting deflections without putting excessive load stress on either tooth end.
  • Zero Bevel Gear:-
  • This gear is similar to straight bevel gears but the only difference is that teeth are curved lengthwise.
  • These teeth are arranged in this manner that the effective spiral angle is zero
Zero Bevel gear

3.Worm Gear:-

  • Worm gears are used to transfer power at 90° and where the high reduction is required.
  • In this worm screw mesh with a worm gear(worm wheel).
    Worm gear is quiet, vibration free and gives a smooth output.
worm gear

Types of worm gear:-

  • Non-throated worm gear
    These don’t have a throat or groove around the circumference of worm wheel or worm screw.
  • Single –throated
    In this worm wheel is throated.
  • Double-throated
    In this, both worm wheel and worm screw are throated.

4.Rack and Pinion

  • Rack and Pinion used to convert rotational motion into linear motion.
  • A rack is flat tooth bar and gear is the pinion.
  • Such type of mechanism is used in an automobile to convert rotation of the steering wheel into the left-to-right motion of the tie rods.
Rack and pinion

         Different Types:-

  • Straight Teeth
    Tooth axis is parallel to the axis of rotation and load transfer is manual.
  • Helical teeth
    Teeth are twisted along a helical path in the axial direction and helix angle of a helical rack is set at 19 degree 31’42” by many racks manufactures.
    2. This gear is quieter and user-friendly than straight tooth gears.
helical rack and pinion
  • Roller Pinion
    This one is advanced rack and pinion gear, in this spur gear teeth is replaced with bearing supported roller that mesh with the teeth of that rack to provide minimal to no backlash.
    2. The Roller Pinion System is capable of speeds as high as 11 m/sec. Even at these speeds, the extremely low friction design does not create heat or significant wear on components.
    3. The RPS system is capable of positional accuracy up to ± 30 μm and repeatability of ± 5 μm at its meshing line or circle.
roller rack and pinion gear

5.Helical Gear

  • Helical gears are used for parallel shaft drives. Helical gears have their teeth inclined to the axis of the shafts in the form of a helix.
  • Their teeth are longer than spur gears and have better load sporting capacity.
  • Their touch ratio is higher than spur gears and that they operate smoother and quieter than spur gears. Their precision rating is ideal. they’re recommended for extremely high speeds and masses.
  • The helix angle references the axis of the cylinder, distinguishing it from the lead angle, which references a line perpendicular to the axis.
  • The helix angle of helical gear is 7 to 23 degree and it must be the same for both the mating gear.
helical-gear

6.Herringbone Gear

  • Herringbone gears are also called as double helical gears. They are used to transmit power either parallel or less perpendicular axis.
  • The unique tooth structure of a herringbone gear consists of two adjoining opposite helixes that appear in the shape of the letter ‘V’. They don’t have any clearance between them.
  • The disadvantage of herringbone gear is that it cannot be cut by simple gear hobbing machine.
herringbone gear

7.Internal and External Gear

  • In the Internal type of gear teeth are formed on the inner surface of a cylinder.
  • In the External type of gear teeth are formed on the outer surface of a cylinder.
Types of Gear internal gear
Types of Gear External gear

8.Face Gear

  • This gear also called as crown gear and this gear has angular gear system and typically consist of grooved, disk-shaped gear combined with a spur, Helical or conical pinion.
  • Face gear transmits power at a right angle in a circular motion.
  • This gear has planar pitch surface and a planar root surface, and both surfaces are perpendicular to the axis of rotation.
  • The main advantage of face gears is the axial freedom of the pinion. This makes these gears particularly useful in applications that require low backlash, such as in robot drives or low antennae drives.
  • They are highly used in the helicopter industry
Types of Gear Face gear

9.Sprockets

  • Sprockets are rotating part with teeth that are used in conjunction with a chain and almost always, at least one other sprocket to transmit torque.
  • They are typically used in conveyor systems and are used to run chains or belts.
  • They are used in chain drives, in motorcycle and bicycles.
Sprockets gear Types of Gear

Author:-

Gopinath Murthi

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