Hydraulic Braking System

Force applied on brake pedal is transmitted to break shoes for its actuation through confined liquid known as "brake fluid". Usually the brake fluid is a mixture Glycerin and Alcohol or Castor oil, Dehydrated alcohol and some additives.The hydraulic brake fluid should passes the following characteristics:t  

1. It should not soften the rubber parts used Braking System.

1. It should not corrode metallic parts used in system.

1. It should not vaporized easily.

1. It should retain flow at lower temperature.

1. It should help for lubrication.

1. It should not loose its characteristics easily.

1. It should be non compressible.

The hydraulic braking system consists of-

1. Master cylinder

1. Wheel cylinder

1. Brake drum

1. Brake shoes

1. Brake fluid with brake lines

The master cylinder is connected by tubing two wheel cylinder at each of four wheels. This system is filled with brake fluid under light pressure when brakes are not in operation.

Each wheels consists of a braking drum, which is mounted on inner side of the wheel and revolves with it. to break shoes are mounted inside the brake drum, which does not rotate. The brake shoes are fitted with Heather and wear resisting brake lining on their surface.

The brake pedal is connected to the master cylinder piston by means of Piston rod. For application of brake, driver presses the brake pedal, which moves the Piston in master cylinder, increasing pressure of fluid in master cylinder and in entire hydraulic system. This pressure is instantly transferred to all four wheel cylinders. Piston in wheel cylinder moves outwards moving brake shoes against brake drum to apply brakes.

When driver releases the brake pedal, the master cylinder Piston returns to its original position due to return spring, dropping fluid pressure. Brake shoe retracting spring pulls the brake shoes from brake drum  to their original position and brakes are released.

Master cylinder:

The purpose served by Master cylinder is:

To build the hydraulic pressure required to operate the system.

To bleed or force air out of the brake line and wheel cylinder.

To act as reservoir to maintain a constant volume of fluid in system.

OIL FILTER

OIL FILTER

• An absolutely clean fluid essential for reliable operation of hydraulic system.
• Now sophisticated machines like CNC/VMC machines use high pressure oil which demands very very clean oil .
• To clean the oil is a main function of oil filtets. Filters are cleaning stations used to arrest the unwanted materials/particles.
• The hydraulic oil is having following general contaminations:

1. Particles ( micron size - metallic/fibrous/dirt)
2. Water
3. Chemical reaction products such as sludge
4. Rubber chips or particles of seats/hoses carried by following oil.
5. Other fluids.

• Effect of contaminants: hydraulic system are advancely affected by contamination. If we do not use filter then all these contaminants will flow everywhere with oil, and will block or jam the moving parts. This jamming may result in damaging the entire system. Every dirt particles of 20 micron size can arrest or stop the entire hydraulic system.
• Filters can be classified as:

1. Full flow filters
2. Proportional flow filters

(A) Full flow filters: as shown in figure oil comes into port A passes through filter element and goes out through port B in this filter all flow passes through filter hence is called full flow filter.

This is very efficient filter but the only drawback of this filter is there is a large pressure drop. When filter element of the filter in packed with arrested particle then the pressure drop still increases.

(B) Proportiona flow filters:

In this type mean oil flow passes through Venturi, which creates localized low pressure area inside the filter element. We can see that on outside of filter element this is high pressure oil.

due to pressure difference created across filter element proportionate quantity of oil passes through filter element. In this filter the pressure drop across the filter is very low. Hence, is having wide application.

• Filtration materials:  Filter material is wire mesh/screen or paper, cotton, celulocel. Following is the list of fabrication materials for filter media used in Hydraulic oil filter.

1. Felt
2. Paper
3. Fabric
4. Wire mesh
5. Wire cloth
6. Glass fibre
7. Paper disc
8. Phenolic rasin
9. Sintered woven wire
10. Sintered PTFE
11. Membrane filter
12. Magnetic filter cloth

• Symbol of filter :  The symbol of inter is as shown figure.
  
• Location of filter: Filter can be located at three suitable locations in Hydraulic circuit.

1. Return line filter
2. Suction line filter
3. Pressure line filter

(A) return line filter:

• This is common location of filter.
• as you can see that oil is supplying to motor through port A motor is rotating. The oil is returning through port B via DC valve through filter F1 . The oil is collected in oil tank.
• B major disadvantage of this location is that, contaminants are removed only after leaving the system.
  

(B) suction line filter

• Now, in this location we have fixed the filter on suction line of pump. Hence oil will be filtered before entering into the pump. This prevents random entry of large and other contaminants.
  
  
  
  
  
  
  
  
  
  
  

(C) Pressure line filter:

• In this arrangement the filter is located after pump or on delivery side of pump. Full pressure is created by pump and this oil is entering into the filter. This arrangement prevents entry of contaminants generated in the pump into components like valves, actuators etc. Since filter is subjected to high pressure oil, its construction must be robust.

Work study

INDUSTRIAL ENGINEERING

Industrial Engineering is "a branch of engineering that is concerned eiwi improvement in the system to do rhithiin a better, simplified and organized way" .

Industrial Engineering is also definsd as"the branch of engineering that is concerned with desugndes and managing system to make the best use of industrial resources such as workrrs, material, equipment, and information".

Need of industrial Engineering

An individual engineer is needed to perform the following activities in an organization.

1. To design system for easy flow of material within manufacturing plants.
2. To prepare system that will evaluate job performance and subsequently productivity of the organization.
3. To design proper working conditions and a proper financial return system for workers.
4. To enact quality control procedures to resolve production problems or minimize costs.

Objectives of Industrial Engineering

1. Define proper work methods.
2. Use quality tools and data to anticipate and solve issues in the engineering process.
3. Frame policy to give proper incentives to workers.
4. Apply financial engineering to reduce losses and increase profit of organization.
5. Perform root cause analysis to imptoim poor performing processes.
6. Ensure human factors engineering is implemented on shop floor for better working conditions.

Scope of IndudIndus Engineering

The scope of Industrial Engineering covers the objectives mentioned above aspect from the one mentioned below;

1. Develop budgets and forecasts for operating cost.
2. Develop proposals for new projects.
3. Determine capacity requirements and subsequent investment options.
4. Develop long range planning models, typically 5-10 years in scopes.
5. Ensure product quality, delivery date and cost is maintained.

INTRODUCTION TO WORK STUDY

Work study is defined as "a management technique which is employed to improve the activities in the production".

The British standard institution defined work study as " a generic terminal for those techniques, particularly method study and work measurement, which are use in the examination of human work in all its contexts and which lead systemaatisyst to the investigation of all the factors which effect the efficiency and economy of the situation being reviewed, in order to effect improvement.

Work study procedure

To increase the productivity follow the below steps;

1.  Select :- The process or job to be studied.
2. Record :- All the relevant facts about the present method.
3. Examine :- The facts critically and in ordered sequence.
4. Develop :- The most practical, economic and effective method. 
5. Measure :- The quality of work involved and calculate standard time.
6. Define :- The new method so that can always be udentident.
7. Install :- The method as standard practice. 
8. Maintain :- The standard practice by regular routine checks.