Types of Gears and their Applications

Sharing is caring
  •  
  •  
  • 2
  •  
  •  
    2
    Shares

Gears are mechanisms used to transfer motion from one shaft to another. From automobiles to machinery. Gears are used to transfer motion from one shaft to another. Different types of gears have different applications. For Example, spur gears are used to transfer motion between parallel shafts. Whereas Rack and Pinion gears are used to convert rotational motion into linear motion. In this article we will discuss various types of gears and their applications.

We suggest you read this article on Gear Terminology and Gear Ratio Calculations.

Types of Gears

According to type of motion, a gear transfer from one shaft to another. Gears are classified in the following types. Each gear type has different applications.

Spur Gear

Spur gears are a type of simple gear. They have teeth parallel to the gear axis. Spur gears are used to transmit power between parallel shafts. They have applications in:

  • Automobiles
  • Bicycle
  • Machines
  • Mechanical Clocks etc.
Spur gears have teeth parallel to the gear axis. They are used to transmit power between parallel shafts.

Advantages :

  • Simple in construction and easy to manufacture.
  • Low Cost and high efficiency.
  • Various gear ratios can be achieved.

Disadvantages :

  • Noisy.

Helical Gears

Helical gears have teeth inclined to the gear axis. For the same width, helical gears have longer teeth compared to spur gears. Therefore they can transfer more power between parallel shafts compared to spur gears.

Helical gears have teeth inclined to the gear axis. For the same width, helical gears have longer teeth compared to spur gears.

Helical gear are used to transfer heavy loads at very high speed between parallel shafts. Applications of helical gear includes:

  • Automotive gearboxes. 
  • Printing and other machinery
  • Conveyors and elevators
  • Factory Automation etc.

Advantages

  • Higher load carrying capacity and contact ratio compared to spur gears.
  • Smoother and quieter than spur gears. 
  • Good precision rating.

Disadvantages

  • Lower efficiency compared to spur gears.
  • Helix angle also increases axial thrust on the shaft.
Herringbone and Double Helical Gear

They are double helical gears with opposite helical teeth. Double Helical gear has a groove in the middle between the teeth. Whereas Herringbone gear does not have groove.

Both gear types are used to transfer power between parallel shafts. Compared to helical gear they offer the advantage of balancing axial thrust in both directions.

Herringbone gears are used for high load carrying capacity requirements. Therefore they are used in Differentials and heavy machinery.

Double Helical Gear
Herringbone Gears

Advantages:

  • Reduced axial force
  • Smoother transmission and engagement
  • Reduced noise
  • Self centering capability
  • High load capacity

Disadvantages:

  • Difficult to manufacture
  • High Cost.

Rack and Pinion

A rack is a cylindrical gear with infinite radius. Whereas pinion is a spur gear. They are used to convert rotational motion into linear motion.

A rack is a cylindrical gear with infinite radius. Whereas pinion is a spur gear. They are used to convert rotational motion into linear motion.

Since rack is a gear with infinite length. Which is not possible in the real world. Therefore rack and pinion gears can not transfer continuous motion. Therefore they are used to transfer transnational motion.

Rack and Pinion Gear application includes: 

  • Convert car steering wheel rotation into side motion of wheels.
  • Lifting Mechanisms
  • Shaper machine. 
Bevel Gear

Bevel gears have a cone surface and its teeth are cut along that cone surface. These types of gears are used to transfer motion in perpendicular direction at higher velocity ratios. Bevel gears have applications in:

  • Machine Tools : Lathe and milling Machine.
  • Garden Equipment.
  • Positioning Equipment
  • Automotive differentials and right angle drives etc.
1) Straight Bevel Gear

Straight bevel gears transfer power between perpendicular shafts. 

Advantages

  • Operate under high speeds and high loads.
  • Good precision rating.

Disadvantages

  • Difficult to manufacture
2) Spiral Bevel Gear

Spiral bevel gears transfer power between perpendicular shafts. They have applications similar to straight bevel gears.

Advantages

  • Higher load carrying capacity compared to straight bevel gear
  • Smooth Operation

Disadvantages

  • Lower efficiency compared to straight bevel gear.
Worm and Worm Wheel

Worm and worm wheel consists of a worm (similar to a screw) and a worm gear (Helical gear). They are used in right-angle skew shafts. These gears have a sliding contact. To reduce friction worm is manufactured in hard material whereas worm wheel is manufactured in soft material.

Worm and worm wheel consists of a worm and a worm gear. They are used in right-angle skew shafts.

Worm and Worm wheel gear has application in devices both at home and in heavy machinery. Some of its applications include:

  • Elevators and Lifts
  • Tuning Instruments : Guitar
  • Of Road Vehicles

Advantages

  • Gear engagement occurs without any shock.
  • Compact Drives
  • Quieter operation
  • High reduction ratios (8 to 400)

Disadvantages

  • Considerable amount of heat is produced due to Friction. 
  • Low Efficiency (from 90% to 40 %)
  • Higher speed ratio gears are non-reversible.
  • Lubrication is required for heat dissipation and for improving efficiency.

Spiral Gear

Spiral Gears are also known as crossed helical gears with high helix angle. They are used to transmit power between two non-intersecting non-parallel shafts.

They are used for low load and low speed applications such as instruments, sewing machines etc.

Disadvantages

  • Poor precision rating
Hypoid Gear

A Hypoid Gear is a type of spiral bevel gear whose axis does not intersect with the axis of the meshing gear. The shape of a hypoid gear is a revolved hyperboloid. In other words pitch surface of the hypoid gear is a hyperbolic surface.

Hypoid gears are typically used in rear-drive  automobile drive trains. Buy now these gears are replaced by spiral gears. But these gears are still common in large vehicles because they can transfer large torque.

Internal Gears

Internal Gears transmits power between parallel shafts. In this bigger gears have teeth on the inner periphery and both driver and driven gear runs in the same direction.

Internal gears has applications involving planetary gear drives (Planetary, solar and star) and gear couplings. 

Advantages

  • Very Compact in size

Disadvantages

  • Not recommended for precision meshes because of design, fabrication, and
    inspection limitations.

Conclusion

To sum up, various types of gears are used to transfer motion from one shaft to another. For Example, spur gears are used to transfer motion between parallel shafts. Whereas Rack and Pinion gears are used to convert rotational motion into linear motion.

Got Questions? 

We will be happy to help.

If you think we missed Something? You can add to this article by sending message in the comment box. We will do our best to add it in this post.


Sharing is caring
  •  
  •  
  • 2
  •  
  •  
    2
    Shares

Add a Comment

Your email address will not be published. Required fields are marked *