Automotive Suspension system

The function of the suspension system is to provide a smooth & comfortable journey to the passenger

1. Session: Vehicle Suspension System 2/26/2019 16MT407 - Theory of Automobile Engineering 1 MODULE 1

2. SESSION OBJECTIVES 2/26/2019 16MT407 - Theory of Automobile Engineering 2 On the completion of this session, the students might be able to understand , Proper selection of suspension system for your vehicle. Good chosen of shock absorber for comfort ride

3. Topics Introduction Types of suspension system Basic suspension movements Suspension springs Shock absorber 2/26/2019 16MT407 - Theory of Automobile Engineering 3

4. INTRODUCTION 2/26/2019 16MT407 - Theory of Automobile Engineering 4 Where suspension system is located in vehicle? It’s located b/n wheels & Body of the vehicle Purpose of suspension system: Connects the vehicle body & the wheels & thus supports the weight of the vehicle Absorb the vibration & shocks from the road surface. Improve the driving comfort and protect the passenger from the road shocks. It ensures that the wheels always contact with road surface . And maintain the inclination of body in order to improve the stability of the vehicle in any possible driving condition including acceleration, braking and cornering.

5. TYPES OF SUSPENSION SYSTEM 2/26/2019 16MT407 - Theory of Automobile Engineering 5 Types of Suspension System Rigid Axle S uspension S ystem Independent Suspension System

6. TYPES OF SUSPENSION SYSTEM 2/26/2019 16MT407 - Theory of Automobile Engineering 6 Rigid Axle Suspension system : Also called non independent suspension system. Here right & Left wheel attached to the same solid axle. When one wheel expose to bump on road, causes a slight tilt on other wheel.

7. TYPES OF SUSPENSION SYSTEM 2/26/2019 16MT407 - Theory of Automobile Engineering 7 Independent Suspension system : No axle beam connecting the left & Right wheels Load directed to the wheel is supported by the suspension arm. Each wheel moves independently in response to its specific road condition. Provides driving comfort & stability

8. TYPES OF SUSPENSION SYSTEM 2/26/2019 16MT407 - Theory of Automobile Engineering 8 Rigid Axle Suspension Independent Suspension Irregularities encountered wheel axle tilts and wheel no longer remains vertical Irregularities encountered wheel axle does not tilts and wheel remains vertical The riding comfort is reduced The riding comfort is increased Road adhesion is decreased Road adhesion is increased Chances of wobbling of wheels No wobbling of wheels Leaf spring are used in this type Coil spring or Torsion bar are generally used Generally used in large vehicles like trucks & Buses Generally used in cars & Light commercial vehicle

9. TYPES OF SUSPENSION SYSTEM 2/26/2019 16MT407 - Theory of Automobile Engineering 9 Suspension arrangement in vehicle : It differs in vehicle at each case. Some time front & Rear suspension are not same. Different suspension arrangement: Conventional Rigid axle suspension at both front & Rear. Conventional rigid axle suspension at rear & independent suspension at front. Independent suspension at both Front & Rear

10. TYPES OF SUSPENSION SYSTEM 2/26/2019 16MT407 - Theory of Automobile Engineering 10 Types of Front wheel suspension system: Independent suspension universally chosen for front axle, due its simplicity. Wishbone type or parallel link type (Double Wishbone system) Macpherson strut type Vertical guide type Trailing Link type Swing half – axle type

11. TYPES OF SUSPENSION SYSTEM 2/26/2019 16MT407 - Theory of Automobile Engineering 11 Double Wishbone suspension: Consists of two wishbone shaped arms, a coil spring, a shock absorber assembly. Each arm is connected to steering knuckle via bushes The two arm are like the two legs of chicken wishbone or letter V Upper wishbone arms are shorter in length than the lower ones This helps to keep the wheel track constant. There by avoid the tyre scrub & thus minimizing the tyre wear. Legs of Chicken Wishbone or Letter V

12. TYPES OF SUSPENSION SYSTEM 2/26/2019 16MT407 - Theory of Automobile Engineering 12 Double Wishbone suspension: On Front Axle The upper Positioned in the region above the top of the wheel. Side force experienced during cornering do not cause the wheel alignment to be disturbed.

13. TYPES OF SUSPENSION SYSTEM 2/26/2019 16MT407 - Theory of Automobile Engineering 13 Double Wishbone suspension: On Rear Axle The upper arm generally Positioned inside the radius of the wheel in order to have large cabin space. This is known as “In wheel – Type – Double – Wishbone suspension” This system consists of upper arm, lower arm, shock absorber assembly. Regards of external force, the lower arm can move in a small amount in lateral & transverse direction. It improves driving comfort & ensure no disturbance in Wheel alignment.

14. TYPES OF SUSPENSION SYSTEM 2/26/2019 16MT407 - Theory of Automobile Engineering 14 Double Wishbone suspension: Advantage Disadvantage Ride Quality is Good Initial cost is more Improved Steerability Maintenance cost is more Ground Clearance increase Required frequent wheel alignment , Otherwise increase tyre wear

15. TYPES OF SUSPENSION SYSTEM 2/26/2019 16MT407 - Theory of Automobile Engineering 15 Macpherson Strut suspension: More popular & Efficient form of suspension It has one control arm & Strut Assembly A coil spring and shock absorber will normally forms the part of the strut assembly. On rear Axle, The coil spring mounted on the control arm instead of being around the strut. On this type shock absorber connects the knuckle to the frame. For Front Axle For Rear Axle

16. TYPES OF SUSPENSION SYSTEM 2/26/2019 16MT407 - Theory of Automobile Engineering 16 Macpherson Strut suspension: For Front Axle The top of the strut is bolted to a reinforced section of the frame structure. The lower end of the strut is attached to a steering Knuckle. The control arm is also attached to the steering Knuckle An anti roll bar links the two control arms together to reduce the sway (Body Roll) Working : The movement of wheel is controlled by swinging of the lower arms and the compression or extension of the shock absorber

17. TYPES OF SUSPENSION SYSTEM 2/26/2019 16MT407 - Theory of Automobile Engineering 17 Macpherson Strut suspension: Advantages Disadvantages Light in Weight Not suitable for Heavy Motor vehicle Camber do not change, due to up & Down movement of wheels Load carrying capacity is less Maintenance cost is less Initial cost is less Ride comfort is more Improve road safety

18. TYPES OF SUSPENSION SYSTEM 2/26/2019 16MT407 - Theory of Automobile Engineering 18 Vertical Guide suspension: King pin is directly attached to the cross member of the frame It can slide up & Down as shown corresponding to the motion of the wheel and there by compressing or elongating the springs. In this type, wheel track, Wheel base, and wheel altitude remain unchanged. But the system is having the disadvange of less stability

19. TYPES OF SUSPENSION SYSTEM 2/26/2019 16MT407 - Theory of Automobile Engineering 19 Trailing link type independent suspension: Here helical coil spring is arranged in horizontal position rather than vertical position. One end of spring fixed with cross member of frame & Other end with trailing Link. The other end of trailing is attached to the shaft, which carries wheel hub . Frame Side Member wheel hub

20. TYPES OF SUSPENSION SYSTEM 2/26/2019 16MT407 - Theory of Automobile Engineering 20 Trailing link type independent suspension: When the wheel moves up & Down, it winds & Unwinds the helical spring to absorb the wheel vibration due to road irregularities. To check the vibration of the spring a multi plate shock absorber is also provided at the end of the cross member. In some design case, helical spring replaced by torsion bar. Frame Side Member wheel hub

21. TYPES OF SUSPENSION SYSTEM 2/26/2019 16MT407 - Theory of Automobile Engineering 21 Swinging Half axle suspension: Wheels are mounted rigidly on the half axles. Half axles are pivoted on either ends of the chassis member at the middle of the car. Considered as Good concept. But up & Down movement of the wheel causes major changes in the camber angle causing rapid wear.

22. TYPES OF SUSPENSION SYSTEM 2/26/2019 16MT407 - Theory of Automobile Engineering 22 Air suspension: Very popular. Compact & fits well in all automobile Constant height can be maintained with help of leveling valves, even at varying loads act on the vehicle.

23. TYPES OF SUSPENSION SYSTEM 2/26/2019 16MT407 - Theory of Automobile Engineering 23 Air suspension: Four conventional spring replaced by four air spring units. It consists Barrel or dome shaped air chamber called below/Diaphragm is placed It is compressed by specially shaped plunger. Lower end attached to axles & Air chamber is fastened to car frame. Each unit is filled with compressed air, which supports the weight of the vehicle.

24. TYPES OF SUSPENSION SYSTEM 2/26/2019 16MT407 - Theory of Automobile Engineering 24 Air suspension: Leveling valve control the air from & to the spring. This way maintain the car body height parallel to ground. Each leveling valve contains two valves in one unit. One allow the air into dome & Other relieve the air to atmosphere through return line & Lift valve.

25. TYPES OF SUSPENSION SYSTEM 2/26/2019 16MT407 - Theory of Automobile Engineering 25 Air suspension: The compressed air is supplied by an air compressor, Air tank, a pressure regulator, solenoid valve. The compressed air pressure is 200 Mpa & thus maintained by air tank. The air compressor is driven by a belt from the crankshaft pulley.

26. TYPES OF SUSPENSION SYSTEM 2/26/2019 16MT407 - Theory of Automobile Engineering 26 Air suspension: The pressure regulator reduced the pressure up to 120 Mpa. This pressurized air is send by leveling valve to air spring unit. Insufficient air side cause low ride. Now levelling valve send air to the spring unit & adjust the level of vehicle by admitting more air.

27. TYPES OF SUSPENSION SYSTEM 2/26/2019 16MT407 - Theory of Automobile Engineering 27 Air suspension: Advantage High quality ride is achieved. Disadvantage: Cost of the system is high Compressed air supply system is complex Greater maintenance is required.

28. BASIC SUSPENSION MOVEMENTS 2/26/2019 16MT407 - Theory of Automobile Engineering 28 Basic suspension movements: The vehicle move over many irregulaties, Bumps, potholes, as well as different types of roads like bend roads, zigzag roads, resulting in below following movement. Bouncing Pitching Rolling – Centrifugal force act at Center of gravity & Force acting at tyre road contact. Combination of Roll & Pitch is called as Diagonal pitch

29. SUSPENSION SPRINGS 2/26/2019 16MT407 - Theory of Automobile Engineering 29 Basic Requirements of a suspension system: It should have minimum deflection consistent with the vehicle stability in order to provide good cushioning ability along with better ride qualities. It should have minimum unsprung weight. The total weight of the suspension system should be minimum It should minimize the tyre wear. It should have low initial cost, operation cost and maintenance cost

30. SUSPENSION SPRINGS 2/26/2019 16MT407 - Theory of Automobile Engineering 30 Sprung weight : It refers, weight which is supported by suspension springs. Weight of the vehicle body,frame,engine transmission, interior, Fuel & Passenger, constitute the sprung weight.

31. SUSPENSION SPRINGS 2/26/2019 16MT407 - Theory of Automobile Engineering 31 Unsprung weight : It refers, weight which is not supported by suspension springs. It includes the weight of the wheels, Rear Axles, steering linkage, and suspension components. Greater weight – greater absorption of energy. But difficult to restore its original position. Cause tyre deflection & reduce vertical velocity on a road bump. A good suspension system must have less unsprung weight.

32. SUSPENSION SPRINGS 2/26/2019 16MT407 - Theory of Automobile Engineering 32 Springs: The springs in suspension system are used to absorb the up & Down motion of the wheels. During the wheel passes through Bumps & Pot holes. Protects the passengers from getting shocks & Vibration Placed b/n Chassis frame & Axle Torsion Bar Leaf Spring Coil Spring

33. SUSPENSION SPRINGS 2/26/2019 16MT407 - Theory of Automobile Engineering 33 Springs: Leaf Spring Made up of several flat long strips made from spring steel of rectangular cross section. Each strip is called leaf. Here several strips are placed one after another & held together by means of Bolt & Clamps. The assembly contains of a main leaf which extends to the full length of the spring. The ends of main leaf are formed with loops known as eyes.

34. SUSPENSION SPRINGS 2/26/2019 16MT407 - Theory of Automobile Engineering 34 Springs: Leaf Spring The other leaves in the spring are attached to the main leaf by means of center bolt and clamps. The length of each succeeding leaf is shorter than preceding one & the complete assembly acts as flexible leaves. When the vehicle is goes over Bump, the spring flattens up and increase in length and during rebound, the spring return back to it shape thereby decreasing in length. Bronze bushes are fitted in the eye for reducing wear . Some times rubber bushes are used, which never required lubrication

35. SUSPENSION SPRINGS 2/26/2019 16MT407 - Theory of Automobile Engineering 35 Springs: Leaf Spring Advantage : Commonly seen in automobile from mid of 1970’s Now days cars used Coil spring, Heavier vehicle only used leaf spring, for its wide load spreading character Coil spring transfer to a point, can’t used in Heavy vehicle.

36. SUSPENSION SPRINGS 2/26/2019 16MT407 - Theory of Automobile Engineering 36 Springs: Leaf Spring Disadvantage : Leaf gets broken, while the vehicle travel over rough road & Carry heavy load. The broken leaf must need to be replaced by new one for using it again. Graphite grease should be applied b/n leaves before assembling it. Sometimes continuous use, spring get sagged or get straightened. In this case particular spring leaf taken out for hammering to retain its same shape. This is known as Cambering of spring

37. SUSPENSION SPRINGS 2/26/2019 16MT407 - Theory of Automobile Engineering 37 Springs: Types of Leaf Spring a.) Full Elliptical leaf spring: This type of leaf spring refers to two semi-elliptical springs connected at their ends, to form a shape of an ellipse

38. SUSPENSION SPRINGS 2/26/2019 16MT407 - Theory of Automobile Engineering 38 Springs: Types of Leaf Spring b .) Three quarter Elliptical leaf spring: This type of leaf spring refers to one semi-elliptical spring connected over a quarter elliptical spring. Chassis Frame

39. SUSPENSION SPRINGS 2/26/2019 16MT407 - Theory of Automobile Engineering 39 Springs: Types of Leaf Spring c .) Semi Elliptical leaf spring: This type of leaf spring refers to forming the shape of half ellipse.

40. SUSPENSION SPRINGS 2/26/2019 16MT407 - Theory of Automobile Engineering 40 Springs: Types of Leaf Spring d .) Quarter Elliptical leaf spring: This type of leaf spring refers to forming the shape of half of semi – elliptical spring. This type of system is also called as cantilever spring system.

41. SUSPENSION SPRINGS 2/26/2019 16MT407 - Theory of Automobile Engineering 41 Springs: Types of Leaf Spring e .) Transverse leaf spring: This type of leaf spring refers to a semi elliptical spring mounted in a inverted manner.

42. SUSPENSION SPRINGS 2/26/2019 16MT407 - Theory of Automobile Engineering 42 Springs: Types of Leaf Spring f.) Platform type leaf spring: This type of leaf spring refers to a quarter elliptical leaf spring with extensive platform supported by shackle.

43. SUSPENSION SPRINGS 2/26/2019 16MT407 - Theory of Automobile Engineering 43 Springs: Helper Springs Mounted directly on the main springs. Used in commercial vehicles such as trucks and buses to provide additional support for heavy loads at rear end only. Fixed on the top of the rear main spring. With the help of center bolt and then clamped with U-Bolt to the rear axle. During light load on vehicle, main spring are in active. In case of heavy loads, the helpers springs rest against the brackets on the frame. Now both the spring share the load Helper Springs Brackets on Frame

44. SUSPENSION SPRINGS 2/26/2019 16MT407 - Theory of Automobile Engineering 44 Springs: Tapered Leaf Springs Consists of 1 to 4 leaves. Designed with reducing thickness from the center to end. Leaf is thick in center & Taper out to the end. All the leaves are approximately of the same length Advantage : Reducing Spring Stresses : Load or stress is spread out evenly along the entire length of the leaf.

45. SUSPENSION SPRINGS 2/26/2019 16MT407 - Theory of Automobile Engineering 45 Springs: Tapered Leaf Springs Reducing Spring Weight: Due to the even stress distribution, allows for maximum use of the material properties and reducing the thickness This minimize the Weight of the spring 60% to the convention spring . Improved ride quality by reducing interleaf friction: Friction b/n Spring during deflection Tapered spring can contact at center & Tips – Suits for small loads or Bumps. Increase spring life: By reducing weight. Zinc rich painting of each leaf greatly extends spring life by postponing the start of corrosion, it cause cracking

46. SUSPENSION SPRINGS 2/26/2019 16MT407 - Theory of Automobile Engineering 46 Springs: Coil Springs – Standard Type Extensive use in commercial vehicle. Made from a length of special spring steel Round in cross section Wound in the shape of coil. Ends of coil springs are kept flat, so that they seat properly. During load, it is more elastic & Compresses By compressing & Expanding the spring, it can absorb the shock, during vehicle moves over Bump & Pot hole.

47. SUSPENSION SPRINGS 2/26/2019 16MT407 - Theory of Automobile Engineering 47 Springs: Coil Springs – Progressive Type It has progressively increase pitch of wire wound. Larger pitch section absorb shocks or Impacts with smaller pitch section of the spring completely compressed, when vehicle moves over Bump. Mostly used in Independent suspension system. Can be assembled in Compact space. Capable of storing twice the energy that than of a leaf spring.

48. SUSPENSION SPRINGS 2/26/2019 16MT407 - Theory of Automobile Engineering 48 Springs: Torsion Bar Made from spring steel bar which function by twisting. One end is fixed with frame, so that it may not turn Other end is attached to the lower control arm. When the vehicle goes over a Bump or Pot hole, It gets twisting effect. This elasticity of the rod is utilized to bring back the wheel to its normal position in the same manner as a spring arrangement

49. SUSPENSION SPRINGS 2/26/2019 16MT407 - Theory of Automobile Engineering 49 Springs: Torsion Bar Advantage: More durability Easy adjustability of ride height. Small space required to mounting. Disadvantage: Cannot provide a progressive spring rate.

50. SUSPENSION SPRINGS 2/26/2019 16MT407 - Theory of Automobile Engineering 50 Springs: Rubber Torsion Unit Design is similar to the steel torsion bar type. The twisting member, consists of two tubes of different sizes vulcanized to a rubber core. The outer tube is fixed with chassis frame. While inner tube serves as a shaft for suspension arm over which the wheel is fitted.

51. SUSPENSION SPRINGS 2/26/2019 16MT407 - Theory of Automobile Engineering 51 Springs: Rubber Torsion Unit As the wheel moves up & Down, the suspension arm swings, which twists and untwists the inner tube. Since the inner tube is vulcanized with outer tube, That medium of rubber provides springing action.

52. SUSPENSION SPRINGS 2/26/2019 16MT407 - Theory of Automobile Engineering 52 Springs: Rubber Torsion Unit Advantage: Excellent vibration damping. Rubber spring system is more compact. Can store greater energy per unit weight than steel. No abnormal squeaking Noise

53. SHOCK ABSORBER 2/26/2019 16MT407 - Theory of Automobile Engineering 53 Shock Absorber: Purpose Vehicle experience impact force while it moves over road irregularities. Here the spring flexes to absorb the impact force. But spring oscillate in vertical direction for a finite time period & can return to its original position. In order to damp down the oscillating motion of springs for ensure the driving comfort & Steerability a shock absorber is used Shock absorber act as a damper.

54. SHOCK ABSORBER 2/26/2019 16MT407 - Theory of Automobile Engineering 54 Shock Absorber: Types Shock Absorber Mechanical Shock Absorber Hydraulic Shock Absorber

55. SHOCK ABSORBER 2/26/2019 16MT407 - Theory of Automobile Engineering 55 Shock Absorber: Mechanical Consists of two links Connected with each other by means of pins One link is connected to the frame of the vehicle. Whereas other link is fixed with axle. A number of friction disc of different metals are placed in between links This will control the spring action due to its frictional effect. This will help to absorb the road shock But obsolete now days due to its non predictable damping characteristics

56. SHOCK ABSORBER 2/26/2019 16MT407 - Theory of Automobile Engineering 56 Shock Absorber: Hydraulic It uses a fluid Which passes through an orifice It resisting the fluid movement The resistance force that is created at this time which is used to suppress the motion of the spring. Telescopic Shock Absorber Cam Actuated piston type shock absorber Rotary Vane Type Shock Absorber

57. SHOCK ABSORER 2/26/2019 16MT407 - Theory of Automobile Engineering 57 Principle of Hydraulic Shock absorber: Simplified Version of a shock absorber. In this set up , a piston having orifices moves up & Down inside an oil filled cylinder. As it moves the oil passes through an orifices in the piston This creates a resistance force (Damping force), which is used to suppress the motion of spring. Effective capacity of the cylinder is reduced, when the piston is introduced into the cylinder in mono tube type. This problem is over come by twin tube type shock absorber. Piston movement allows the oil escape to a reservoir in-between the inner and outer tube. Mono - Tube Twin - Tube

58. SHOCK ABSORER 2/26/2019 16MT407 - Theory of Automobile Engineering 58 Mono Tube Hydraulic Shock absorber: Construction It has Single Tube Only. It has two chamber. Working Chamber Expansion chamber Expansion chamber charged with Nitrogen gas b/n 25 to 30 Bar. It ensure the rebound effect Keeps the working chamber constantly filled with Oil.

59. SHOCK ABSORER 2/26/2019 16MT407 - Theory of Automobile Engineering 59 Mono Tube Hydraulic Shock absorber: Principle Here the oil is forces to flow through the orifices in the piston valve. It is heated. It is the mechanism which allows the shock absorber to dissipate energy stored by the suspension spring. “Road shock is absorbed by converting Kinetic Energy (Energy of Motion) into heat which is absorbed by the oil in the shock absorber”.

60. SHOCK ABSORER 2/26/2019 16MT407 - Theory of Automobile Engineering 60 Mono Tube Hydraulic Shock absorber: Working Compression: When bumps on roads. Oil compress the Gas & Reducing its volume. Rebound: By contrast, the shock absorber is extending. Rod leaves the working chamber. Floating piston moves up. Ensure the pressurized oil in the working chamber

61. SHOCK ABSORER 2/26/2019 16MT407 - Theory of Automobile Engineering 61 Twin Tube Hydraulic Shock absorber: Construction Also called as Direct Double acting Telescopic type Hydraulic Shock absorber. Because shock absorber acts on both the compression (Downward movement of the body) & Rebound stroke (Upward Movement of the body). There are two chamber Outer chamber – Reservoir Inner chamber Piston splits the inner chamber into two. Rebound chamber Compression chamber

62. SHOCK ABSORER 2/26/2019 16MT407 - Theory of Automobile Engineering 62 Twin Tube Hydraulic Shock absorber: Working When the wheels goes over a Bump. The suspension system moves, relative motion b/n the sprung & Unsprung masses force the piston and rod assemble to move or telescope. Piston & valve assembly pushed into the lower chamber of the cylinder. Causing, compressing the oil in the chamber. Since the oil is incompressible, so via the valve orifice it moves to the upper chamber & Reservoir.

63. SHOCK ABSORER 2/26/2019 16MT407 - Theory of Automobile Engineering 63 Twin Tube Hydraulic Shock absorber: Working As the shock absorber is extended during this stroke, oil is drawn into the cylinder tube, equal to the piston rod volume. At the same time air or gas in the reservoir tube expands to account for oil leaving the space b/n the cylinder & reservoir tube “Thus the shock is absorbed by converting Kinetic Energy (i.e Energy of motion) into heat which is absorbed by the oil in the shock absorber”. Damping Force =  

64. SHOCK ABSORER 2/26/2019 16MT407 - Theory of Automobile Engineering 64 Twin Tube Hydraulic Shock absorber: Cavitation As the shock absorber operates excessively, the air inside the reservoir mixes with oil in the form of Bubbles. This phenomenon is commonly known as cavitation. When the pressure is applied to these bubbles. They passes through orifice without generating any resistance force,. Damping force delivered by the shock absorber is reduced. Using of Nitrogen gas is prevent the cavitation problem & Ensure stable operation

65. SHOCK ABSORER 2/26/2019 16MT407 - Theory of Automobile Engineering 65 Cam Actuated piston type Hydraulic Shock absorber : Single Acting cam actuated type : When vehicle moves over Bump. Frame moves downward, Lever moves upward, Cam moves Right side. Intake valve open & It has large port. It offers little resistance to oil flow.

66. SHOCK ABSORER 2/26/2019 16MT407 - Theory of Automobile Engineering 66 Cam Actuated piston type Hydraulic Shock absorber : Single Acting cam actuated type : When vehicle spring rebounds. The car frame moves upwards, Now lever moves downwards, So cam is moved in reverse direction, & Apply the pressure on Piston. The intake valve gets closed. Relief valve send the oil to reservoir from cylinder. This entire action cause damping to the Suspension spring rebound & Suppress it’s oscillation

67. SHOCK ABSORER 2/26/2019 16MT407 - Theory of Automobile Engineering 67 Cam Actuated piston type Hydraulic Shock absorber : Double Acting cam actuated type : This type has two piston. One for regulate vehicle spring rebound. Other regulate vehicle spring compression. One piston is called rebound piston Other is called Compression piston. The pistons are actuated by a cam fitted on a shaft. A lever actuated the cam shaft & there by cam resulting in piston movement.

68. SHOCK ABSORER 2/26/2019 16MT407 - Theory of Automobile Engineering 68 Cam Actuated piston type Hydraulic Shock absorber : Double Acting cam actuated type : Each piston contain one relief valve & Intake valve. Working : During vehicle moves on Bump. The oil flow takes place like Compression cylinder to Reservoir via relief valve At the same time rebound intake valve open due to partial vacuum created in the rebound cylinder & Filling it with oil.

69. SHOCK ABSORER 2/26/2019 16MT407 - Theory of Automobile Engineering 69 Cam Actuated piston type Hydraulic Shock absorber : Double Acting cam actuated type : Each piston contain one relief valve & Intake valve. Working : During vehicle rebounds, Pressure set up in the rebound cylinder forces oil through the rebound relief valve into reservoir At the same time compression intake valve opens, due to the vacuum in it & fill the compression cylinder

70. SHOCK ABSORER 2/26/2019 16MT407 - Theory of Automobile Engineering 70 Rotary Vane type Hydraulic Shock absorber: Construction It contains Round Hollow Body, Fixed to the chassis Frame. Two lobe rotor moves in viscous oil. The rotor divide the body into two chambers & is provided with a valve. The rotor is mounted on a shaft. The other end of the rotor shaft is operated by an actuating arm which is connected with the axle by means of link.

71. SHOCK ABSORER 2/26/2019 16MT407 - Theory of Automobile Engineering 71 Rotary Vane type Hydraulic Shock absorber: Working When a vehicle goes over a Bump. The rotor is moved due to restricted flow of the oil from the valve. So pressure is build up in one chamber. This pressure causes resistance to the movement of the axle. Similarly, during rebound, the oil has to pass through the same valve and causes resistance to the movement of axle.

72. 2/26/2019 16MT407 - Theory of Automobile Engineering 72 END