4-AE-UNIT-3-Brakes.pptx
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The document discusses different types of brake systems. It describes various types of brakes based on their purpose, location, construction, actuation method, application, number of wheels braked, braking contact method, application of braking force, brake gear, power employed, and power transmission. Specific brake types are mechanical expander brakes, drum brakes, disc brakes, hydraulic brakes, air brakes, and vacuum brakes. Hydraulic brakes are described as having advantages like equal braking to all wheels, simple construction, less wear, self-lubrication, increased braking effort and high mechanical advantage, while their disadvantages include issues with leakage and ruined brake shoes. Requirements for brake fluid
4-AE-UNIT-3-Brakes.pptx
- 2. Types of Brakes 1. Purpose (a) service or the primary (b) parking or the secondary brakes 2. Location 3. Construction (a) drum brakes (b) disc brakes. 4. Method of actuation (a) Mechanical brakes (b) Hydraulic brakes (c) Electric brakes (d) Vacuum brakes (e) air brakes 5. Extra braking effort
- 3. 1. With respect to application: (a) Foot brake (b) Hand brake. 2. With respect to the number of wheels: (a) Two-wheel brakes (b) Four-wheel brakes. 3. With respect to the method of braking contact: (a) Internal expanding brakes (b) External contracting brakes. 4. With respect to the method of applying the braking force: (a) Single acting brakes (b) Double acting brakes. 5. With respect to the brake gear: (a) Mechanical brakes (b) Power brakes. 6. With respect to nature of power employed: (a) Vacuum brakes (b) Air brakes (c) Hydraulic brakes (d) Hydrostatic brakes (e) Electric brakes. 7. With respect to power transmission: (a) Direct acting brakes (b) Geared brakes. 8. With respect to power unit: (a) Cylinder brakes (b) Diaphragm brakes.
- 4. Fig. Mechanical expander brakes (a) Cam-operated (b) Toggle lever-operated. Fig. Drum type brakes. Fig Floating anchor type brake.
- 6. Fig. Caliper type disc brake.
- 7. Fig. Hydraulic brake system.
- 9. Fig. Tandem Master cylinder Fig. Wheel cylinder.
- 11. Fig. Bleeding of brakes.
- 12. Advantages of hydraulic brakes 1. Equal braking effort to all the four wheels (since fluid exerts equal pressure every where the circuit). 2. The system is simple in construction. 3. Less rate of wear (due to absence of joints compared to mechanical brakes). 4. The system is mostly self-lubricating. 5. Increased braking effort. 6. High mechanical advantage. 7. Flexibility in brake lines. 8. The hydraulic brakes can also provide differential braking action between the front and rear brakes by using the wheel cylinder of different size for the front and rear wheels.
- 13. Disadvantages of hydraulic brakes 1. Even slight leakage of air into the braking system makes it useless. 2. The brake shoes are liable to get ruined if the brake fluid leaks out. 3. This system is suitable only for applying brakes intermittently. For parking purpose separate mechanical linkage has to be employed.
- 14. Requirements of brake fluid 1. Boiling point 2. Viscosity 3. Lubrication properties 4. Effect on rubber 5. Corrosive action 6. Storage Stability
- 15. Air brakes Fig. General arrangement of an air brake system.
- 17. Main parts of an air brake: Following are the main parts of an air brake: (i) Air compressor. (ii) Unloader valve. (iii) Reservoir. (iv) Brake valve. (v) Brake chamber. (vi) Quick release valve (vii) Relay valve. (viii) Warning signal.
- 18. Advantages and Disadvantages of air brakes Advantages of air brakes 1. Much more powerful than the ordinary mechanical or hydraulic brakes (that is why these are exclusively used in heavy vehicles). 2. Simplified chassis design. 3. The compressed air from reservoir, apart from braking, can be used for tyre inflation, windscreen wipers, horns etc. Disadvantages of air brakes 1. Involve relatively more parts. 2. The air compressor uses a certain amount of the engine power.
- 19. Vacuum Brakes Fig. Vacuum Servo Brake.