Transmission system of Automobiles

In this PPT Transmission Element in the automobile is discussed.

1. UNIT-III TRANSMISSION SYSTEMS

2. Transmission System Transmission System is the system by means of which power developed by the engine is transmitted to road wheels to propel the vehicle. In Automobile the power developed by the engine which is used to turn wheel. Therefore the engine is connected to the transmission.

3. Transmission Arrangement

4. Purpose of Transmission system It enables the running engine to be connected or disconnected from the driving wheel smoothly and without shocks. It enables the reduction of engine speed. It enables the driving wheels to driven at different speeds.

5. CLUTCH Characteristics of a clutch Transmission of torque Gradual engagement Dissipation of heat Dynamic balancing Vibration damping Size of the clutch Free pedal clutch play Non-exertive operation of disengagement

6. Clutch Clutch is a mechanism used to connect or disconnect the engine from the rest of transmission elements. It is located between engine and gear box. During normal running and stationary position, it is always in engaged condition. It is always in engaged condition.

7. Principle of Operation of friction clutch

8. TYPES OF CLUTCH Friction clutch a) single plate clutch b)Multi plate clutch Wet type Dry type c) cone clutch 2. Centrifugal clutch 3. Semi centrifugal clutch 4. Coil pressure spring clutch 5. Conical spring clutch or diaphragm clutch a) Tapered b) Crown spring 6. Positive clutch- dog and spline clutch 7. Hydraulic clutch

9. Single plate clutch

10. Single plate Clutch It is most commonly used in motor vehicle such as cars, trucks and tractors. Various parts of Single plate Clutch- Fly wheel. Pilot Bearing. Clutch plate. Pressure plate. Clutch cover assembly.

11. Multi-plate Clutch Multi-plate clutch are used in heavy vehicles racing cars and motorcycles for transmitting high torque. They are smooth and easy to operate due to their assembly of friction surface’s contact. This clutch are of two types wet type and dry type.

12. MULTI PLATE CLUTCH

13. Multi-plate clutch The wet type clutch plate are oil immersed clutch this types of wet clutches are generally used in conjunction with a part of automatic transmission. advantages – It is highly reliable. It is suitable for heavy vehicles. Increased torque transmission capacity could be obtained .

14. Cone clutch The cone surface of this type of clutch are in form of cone. It is called cone clutch. It consist of two cones having two leather facing. This cones are known as male and female cone. One cone is fixed to the driving member and other cone is fixed to the splined driven shaft.

15. CONE CLUTCH

16. Cone clutch Advantages- Normal force acting on the contact surface is larger than the axial force which reduces the effort required to operate the clutch. Disadvantages- If the angle of cone is smaller than 20’, the male cone tends to bind or joint in the female cone.

17. Centrifugal clutch Centrifugal clutch is controlled by the engine speed through an accelerator. When the speed decrease the clutch gets disengage. When the speed rises above the predetermined value the clutch is engaged. Greater is the centrifugal force due to higher engine speed, more will be powerful contact.

18. CENTRIFUGAL CLUTCH

19. Semi centrifugal clutch In this clutch plate the pressure between plates is increased as the speed of rotation of the clutch in proportional to the pressure requirements. As speed increases, the rotating weights will tend to move the pressure plate towards the flywheel.

20. The ends of release levers are also moved back against the throw out bearing along with this movement of the pressure plate.

21. SEMI CENTRIFUGAL CLUTCH

22. DIAPHRAGM CLUTCH

23. POSITIVE CLUTCH OR DOG AND SPLINE CLUTCH

24. HYDRAULIC CLUTCH

25. ELECTROMAGNETIC CLUTCH

26. Gear box Gear box is a speed and torque changing device. It changes speed and torque between engine and driving wheels. More power is required to keep an automobile in motion when compared to power required for keeping it rolling after starting.

27. Gear box Necessity of Gear box- When the vehicle is running, various resistance oppose it. In order to keep vehicle moving at uniform speed , a driving force or tractive effort is equal to the sum of all opposing force.

28. Purpose of transmission It helps the engine to disconnect from driving wheels. It helps the running engine to be connected to the driving wheel smoothly and without shock. It provides the leverage between engine and driving wheels to be varied. It helps the driving wheels to be driven at different speed.

29. Tractive effort The torque available on the wheel produce a driving force which is parallel to the end known as tractive effort.

30. GEAR BOX TYPES OF GEAR BOX 1.Manual transmission a) Sliding mesh gearbox b) Constant mesh gear box c) Synchromesh gear box 2. Epicyclic gear box 3. Automatic gear box a) Hydromatic gear box b ) Torque converter gear box

31. Sliding mesh Gear Box Sliding mesh gear box is a transmission system that consist of various sets of gears and shafts that are arranged together in an organized fashion and the shifting or meshing of different gear ratios is done by the sliding of gears towards right and left over the splined shaft with the help of a gear lever operated by the driver.

32. Need of sliding mesh transmission Fuel consumption of an automobile increased as the load on the engine is decreased. Due to varying torque ratio provided by this gearbox, the automobile vehicle is made to go to the hill stations which is possible earlier. Reverse of the car made possible with the introduction of this transmission system.

33. Sliding mesh gear box

34. First Gear

35. Second Gear

36. 3 r d gear

37. 4 th gear

38. Application Alfa 12HP used sliding mesh gearbox with 4 -speed manual transmission. Fiat 6HP used 3-speed manual transmission. Mercedes 35HP used 4-speed manual transmission Renault Voiturette used manual 3-speed transmission.

39. Constant Mesh Gear Box Constant Mesh Gearbox is type of transmission in which all or most of the gears are always in mesh with one another, as opposed to a sliding gear transmission, in which engagement is obtained by sliding some of the gears along the shaft into mesh. In constant mesh gear box, Gear ratios are selected by the small clutches that are connect the various gear sets to their shaft so power is transmitted through them.

40. Constant mesh gear box

41. Constant mesh gear box

42. Synchromesh Gear Box To simplify the operation of changing of gear without the occurrence of clashes and their consequent damage, synchromesh is used in different motors. The main feature of this gear box is The main shaft or output gear is freely rotated on the bushes of the output shaft.

43. Advantages and Disadvantages Gear Changing is very much simplified. Less wear in gear. It allows the usage of helical gear that run directly. Disadvantages The design is very much complex.

44. Automatic Gear Box Various speed are obtained automatically in gear boxes are known as automatic gear box, generally the driver selects the car condition such as neutral , forward or reverse. Such Gear box are of two types Hydramatic Transmission. Torque convertor transmission.

45. AUTOMATIC GEARBOX HYDROMATIC TRANSMISSION

46. First Gear The power transmitted from the flywheel to the torus covers, then to the internal gear and to the planet cage with the sun gear when the front unit is locked thus the engine is running. The planet cage usually moves around the stationary sun gear with reduced speed. The power is transmitted by the cage to the driving torus through the front section of the intermediate shaft.

47. Second Gear The power is first transmitted to the torus covers and then to the locked front unit from the flywheel. The front section of the intermediate shaft transmit the power directly to the fluid flywheel. Then it is transmitted back to sun gear of the rear section.

48. Third gear Now the gear is 1.45 :1, similarly the front unit is engaged, the planet cage is driven by the driven internal gear.

49. Fourth Gear The direct Drive is obtained by controlling the transmission in the front unit. The power is transmitted from the flywheel through the torus covers to the locked front unit. Now the power is transmitted from the flywheel through the torus covers to the locked front unit. The power is transmitted in two paths.

50. Shift or Selector Mechanism For Gear Changing and selecting a particular gear train to operation, the selector mechanism is implemented to obtained the same easier. In this case, the gear are shifted by a gearshift Lever. In Manually operated selective transmission system, the gear shift lever is mounted either on the steering column or floor board.

51. SHIFT OR SELECTOR MECHANISM (a) FLOOR MOUNTED SHIFT MECHANISM

52. (b) MECHANISM WITH GEAR LEVER AS STEERING COLUMN

53. Over drive Mechanism In this the high gear mechanism produces 1:1 ratio Between clutch gear and transmission output shaft. There is neither gear reduction nor gear increase through the Transmission. It is the direct drive. It produces the high cruising speed with comparative low engine speed.

54. Over drive Mechanism The shift to overdrive can be obtained when the car is running above a predetermined cut in speed from 32 to 51 km/ hr by lifting the foot momentarily from the accelerator. The action of the overdrive is controlled by a centrifugally operated switch.

55. OVERDRIVE MECHANISM

56. Transfer Box Transfer Box is a part of a four wheel drive system used in four wheel drive or all wheel drive vehicles. It is also called as transfer gear case. Function of Transfer Gear box- It receives power front the transmission and sends to both front and rear axles. It provides low and high range of speed.

57. TRANSFER BOX

58. Transfer Box Type of transfer Box- Gear driven type transfer box. Chain driven type transfer box. Housing type gear box. Transfer case shift typee .

59. Fluid flywheel It is also known as fluid clutch, which couples the driving members with driven member through the media of fluid. Advantages- It is simple design. No need of adjustment is required. No skill is required for operation.

60. FLUID FLYWHEEL

61. Torque convertor The only difference is that it has an additional stationary member called ‘ Stator or reaction member”. But the operation is not similar. In the case of flywheel, the same torque is transmitted as given by the engine shaft.

62. Torque Convertor Single stage torque convertor- Impeller or driving member- This is driving member is connected to the engine. Turbine or Driven member- This driven member is connected to the road wheels through the transmission gears and the drive line and Stator- It is connected to the frame through a free wheel.

63. TORQUE CONVERTER

64. UNIVERSAL JOINTS

65. Propeller Shaft The propeller Shaft is connected between transmission shaft (i.e. gear box output shaft and pinion shaft) of the differential at the wheel axle. The propeller shaft also called as driveline shaft or drive shaft. The propeller shaft takes power from the engine and a transmits to clutch, transmission gear box unit and driving wheels of the vehicle through the final drive and differential units.

66. PROPELLER SHAFT

67. SLIP JOINTS

68. Differential D ifferential is a system that transmits an engine’s torque to the wheels. The differential takes the power from the engine and splits it, allowing the wheels to spin at different speeds . Major Components of differential- Drive pinion or bevel pinion. Ring Gear or Crown wheel. Differential Case. Differential side gear or Sun gears.

69. Type of Differential Conventional Differential. Limited Slip Differential. Non Slip Differential. Double Reduction differential

70. DIFFERENTIAL

71. DIFFERENTIAL

72. Limited Slip Differential or Self Locking Differential

73. Non Slip Differential The differential is a torque controlled differential. Preloading the system is possible. The Differential is operated by resultant moments. Preload can be adjusted. Advantages- Maximum Traction can be achieved for all grip levels. Fuel Consumption is reduced.

74. Non Slip Differential

75. Rear Axle The power transmitted through rear axle to driving wheels. On Modern passenger cars almost all rear axles are live axles. It includes revolving shafts for driving wheels. In ordinary cars, the live axle will be at the front and the rear axle will be dead which simply remains stationary.

76. Rear Axle All live axle shafts are splitted into two parts in modern cars. Each part is driven by one of the differential gears through a spline connection. Types of Rear Axle- Dead Axle. Live Axle.

77. CONSTRUCTION OF REAR AXLES

78. TYPES OF REAR AXLES ( i ) SEMI FLOATING AXLE

79. (ii)FULL FLOATING AXLE

80. (iii) THREE QUARTER FLOATING AXLE

81. REAR AXLE DRIVES ( i ) HOTCHKISS DRIVE

82. (ii) TORQUE TUBE DRIVE