Types of Brakes

Brakes are the one of the most important safety features on your vehicle. There are different types of brakes, both between vehicle and within a vehicle. The brakes used to stop a vehicle while driving are known as the service brakes, which are either a disc and drum brake. Vehicles also come equipped with other braking systems, including anti lock and emergency brakes.

Disc Brakes

Disc brakes consist of a disc brake rotor - which is attached to the wheel - and a caliper, which holds the disc brake pads. Hydraulic pressure from the master cylinder causes the caliper piston to clamp the disc brake rotor between the disc brake pads. This creates friction between the pads and rotor, causing your car to slow down or stop.

 

 Disc Brake

Drum Brake

Drum brake consist of a brake drum attached to the wheel, a wheel cylinder, brake shoes, and brake return springs. Hydraulic pressure from the master cylinder causes the wheel cylinder to press the brake shoes against the brake drum. This creates friction between the shoes and drum to slow or stop your car.

 Drum Brake

Emergency Brakes

Vehicles also come equipped with a secondary braking system, known as emergency, or parking brakes.  Emergency brakes are independent of the service brakes, and are not powered by hydraulics.  Parking brakes use cables to mechanically apply the brakes (usually the rear brake). There are a few different types of emergency brakes, which include: a stick lever located between the driver and passenger seats; a pedal located to the  left of the floor pedals; or a push button or handle located somewhere near the steering column. Emergency brakes are most often used as a parking brake to help keep a vehicle stationary while parked.  And, yes, they are also used in emergency situations, in case the other brake system fails!

Anti-Lock Brakes

Computer-controlled anti-lock braking systems (ABS) is an important safety feature which is equipped on most newer vehicles. When brakes are applied suddenly, ABS prevents the wheels from locking up and the tires from skidding. The system monitors the speed of each wheel and automatically pulses the brake pressure on and off rapidly on any wheels where skidding is detected. This is beneficial for driving on wet and slippery roads. ABS works with the service brakes to decrease stopping distance and increase control and stability of the vehicle during hard braking.

Function of Clutch and Brake

1. Clutch

            A Clutch is a machine member used to connect the driving shaft to a driven shaft, so that the driven shaft may be started or stopped at will, without stopping the driving shaft. A clutch thus provides an interruptible connection between two rotating shafts. Clutches allow a high inertia load to be stated with a small power.

            Clutches are used whenever the ability to limit the transmission of power or motion needs to be controlled either in amount or over time (e.g. electric screwdrivers limit how much torque is transmitted through use of a clutch; clutches control whether automobiles transmit engine power to the wheels).

2. Brake

2 

           A brake is a mechanical device which inhibits motion. Its opposite component is a clutch. Brake pedal slows a car to a stop. When you depress your brake pedal, your car transmits the force from your foot to its brakes through a fluid. Since the actual brakes require a much greater force than you could apply with your leg, your car must also multiply the force of your foot.

        Almost all wheeled vehicles have a brake of some sort. Even baggage carts and shopping carts may have them for use on a moving ramp. Most fixed-wing aircraft are fitted with wheel brakes on the undercarriage. Some aircraft also feature air brakes designed to reduce their speed in flight. Friction brakes on automobiles store braking heat in the drum brake or disc brake while braking then conduct it to the air gradually. When traveling downhill some vehicles can use their engines to brake.

Type of Clutch

a)    Mechanical Clutch

                  i.        Friction Clutches

Friction clutches are widely used in industry, especially in the automotive industry. It can be driven or operated manually, pneumatically or hydraulically. Friction clutches also serves to move the motion between two mechanical components by using metal-lined metal fibrous and installed between two steel plates. In addition, it can also transfer the movement that occurs when purchased separately plates in contact with each other. In friction clutches system, a trip of friction plates is very small compared with the grip jaws. Part driven friction clutch often supported by bearings in the drive hub.

                      ii.        Jaw Clutches

Jaw clutches typically used on slow speed applications. Jaw clutch serves to engage and be engaged within arm clutch shift.  Branch transitions usually have a fulcrum or pivot point located at one end of the handle arm with operations located at the other end.

                      iii.        Centrifugal Clutches

Type centrifugal friction clutches are usually found in applications where it is desirable to have either no initial charge or protection against overload. It can also function as a coupling or can be mounted directly to the V-belt. In operation, centrifugal clutches will miss the start of or in any other position. Centrifugal clutches to engage positively without any problems during the operation.

                      iv.        Overrunning Clutches

Overrunning clutches are also known as one-way clutches. It is often used on the machine where the media drive motor or in need of protection. To avoid over speeding, drives by allowing free rotation of the drive components. It is designed to allow rotation of the driving force in the forward direction only. To achieve this overrunning action, two common types of roller mechanism is used and sprags. In this system, the rollers will be running on a flat surface in the housing round while sprags positioned between two spherical surfaces. Sprags is not fixed or shaped pieces. During clutch operation, the sprags is wedged between the inner and outer hub.

                      v.        Torque Limiting Clutches

Torque limiting clutches used in any number of different pieces of equipment or even used with any type of roller chain coupling. Half clutch system is always engaged at start up and only when the charge slip.

                      vi.        Tooth Clutches

Pneumatic system used in the clutch teeth of the hydraulic actuator cylinder to the operating system. Mating surface on the clutch gear is built with notches or serrations. In operation, the notched surface connects every other movement sent from the drive to the driven part of the clutch.

b)    Hydraulic Clutches

                      i.        Fluid clutches

Fluid clutch is widely used in industry because they have the ability to start under heavy loads and absorb shock loads. It is also used to provide power flow smoothly driven side of the engine and is also known as a fluid coupling. Fluid clutch driven half of the fluid coupling actuated by hydraulic fluid. Half drive (pump / impeller) and half driven (turbine) will rotate at the same speed during operation.

c)    Electric Clutches

Electric clutch is used where movement occasionally necessary, especially to start and stop the motor drive on a short cycle time. In the electric clutch, coil mounted on the driven component or machine while the armature plate mounted on the motor or drive shaft. When the two parts are de-energized, no contact or anything going on between them, although it can run motor. When electric current is applied to the magnet or coil, a magnetic field is set and will cause the armature and coil pulls together. This action will then install the two parts of the electrical and physical causes them to rotate as one piece.

https://www.youtube.com/watch?v=pqF-aBtTBnY

Clutches and Brakes Maintenance Procedure

    

Check list clutches and brakes maintenance, symptoms and record observations for preventive maintenance.

 1. Improper adjustment of clutch or brake.

 2. Oil or contaminant on friction surfaces.

 3. Worn out friction components.

 4. Worn linkage or parts used in engaging clucth or brake.

 5. Too much torque.

 6. High-frequency cycling or high-inertia loads.



Example of Checklist for clutch and brake maintenance

Introduction of Clutches and Brakes

Keys to effective control and transmission of drive torque, speed, and power in many rotating drive systems are clutches and brakes. Their function is to either transfer torque from an input shaft to an output shaft (clutching) or to stop and hold a load (braking). Though offered as separate components, their functions are often combined into a single unit referred to as a clutch-brake. Clutches and brakes can be categorized by the technique used to engage or stop the load (friction, electromagnetic, mechanical lockup), and by the method used to actuate them (mechanical, electric, pneumatic, hydraulic, self-activating).