What is a Brake?
Brake (or Brakes) is a Mechanical device which absorbs kinetic energy of moving systems and brings them to rest. This absorbed kinetic energy is converted into heat and then dissipated to the environment.
One of the well-known examples of brakes is in automobiles, where they are used to either slow down or stop the vehicle completely.
Classification of Brakes
Brakes can broadly be classified into three main types.
- Mechanical brake
- Hydraulic and pneumatic brake
- Electrical brake
Now we will understand each type of brake in detail.
These brakes are operated by mechanical means like pedals, springs and lever.
Attribution: By AndrewDressel at English Wikipedia, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=34204441
Types of Mechanical Brakes
Depending on the shape of friction material mechanical brakes can further be categorized into
- Block brake
- Disk brake
- External and internal shoe brake
- Band brake
Advantages of mechanical brakes
- Simple in construction and maintenance
- Less expensive compared to hydraulic brake
- They are good for emergency and parking brakes
Disadvantages of mechanical brakes
- Wear and tear happens at brake surfaces
- They are not as effective than hydraulic brake
- Heat dissipation is not uniform
- They are less effective compared to hydraulic brake
Capacity of Mechanical brakes depends on following factors
- The ability of brake to dissipate heat
- Coefficient of friction
- Radius of brake drum
- Contacting area of braking surfaces
- Unit pressure between braking surfaces
Hydraulic and pneumatic brakes
These brakes work on the basis of fluid pressure such as oil or gas.
Advantages of hydraulic and pneumatic brakes
- Heat dissipation is more thorough compared to mechanical brake
- They are durable due to less wear and tear
- They are safe
- They are more effective than mechanical brake
- Braking effort is same for each tire
Disadvantages of hydraulic and pneumatic brakes
- They are more costly than mechanical brake
- Fluid used should be compatible with brake material
- Braking fluid leakage could happen which will result in brake failure
- Construction and maintenance is not as simple as mechanical brake
These brakes work on the principles of electromagnetic forces.
Electrical brakes have following types
- Eddy current brake
- Hysteresis brake
- Magnetic particle brake
Advantages of electrical brakes
- They are fast
- There is almost zero maintenance cost
- Its operation is smooth
Disadvantages of electrical brakes
- They only work while vehicle is moving. It means if we have to park vehicle on a road which has a slope than we have to use mechanical brake. Otherwise the vehicle will move downwards due to gravity.
- They have high initial cost
- Not suitable for high temperatures