Presented by: Gary Wolf

Transcription

1 1 Basic Rail Vehicle Suspension Parameters Presented by: Gary Wolf Wolf Railway Consulting 2838 Washington Street Avondale Estates, Georgia

2 Rail Vehicle Suspension Agenda 3 Primary Suspension Modes Lateral, vertical, yaw/warp Freight Cars Springs and friction dampers Yaw mode and truck warp Passenger/Transit Cars Springs and dampers Lateral suspensions Locomotives 2

3 Primary Role of Suspension 3 1. Absorb vertical and lateral road shocks from perturbations in the track. Springs are used to slow down the accelerations over time, and store the energy. 2. Dissipate the energy stored in the springs to prevent it from amplifying the motions of the road shocks and returning the energy back to the car. Dampers are used to dissipate the energy.

4 Energy Storage in a Spring 4

5 Displacement Typical Motion Response of an Undamped Spring 5 Velocity Acceleration

6 6 Motion Response of a Damped Spring

7 Vehicle Suspension Elements 3 Principal Modes 7 Vertical Suspension Lateral Suspension Yaw/Warp Suspension

8 Vertical Suspension 8 Freight Cars Secondary suspension springs between truck frame and bolster Friction snubbers between frame and bolster No Primary suspension Passenger/Transit Cars Primary suspension between wheelset and frame Secondary suspension between frame and bolster, or frame and body Locomotives Primary and secondary elements

9 Major Bodies Freight Cars 9 Car Body Truck Frame Truck Bolster Secondary Suspension Damper Secondary Suspension Springs No Primary Suspension

10 10 Spring: An Energy Storage Device

11 11 Damper: Dissipates Energy

12 12 Springs and Dampers Working in Parallel

13 Major Bodies Passenger Vehicles Car Body 13 Secondary suspension supports carbody Bolster - swivels on truck Truck frame - holds wheels in place Primary suspension - lets wheel sets move up/down in frame

14 Major Bodies Passenger Vehicles Car Body 14 Bolster Secondary suspension supports carbody Truck frame - holds wheels in place Primary suspension - lets wheel sets move up/down in frame

15 The Standard 3 Piece Truck: A long history of design improvements 15

16 16

17 17

18 18 Bolster and Sideframe Interface Area

19 19

20 20

21 Nominal Wedge Position above top of Bolster 21

22 22 Wear occurs on these 4 surfaces

23 Wedge rise above top of bolster due to wear 23

24 AAR Rule 46 (2007) 24 Developed to address both friction casting front face wear, and total friction casting rise above top of bolster. Rules applicable when: At any time of inspection When car is on repair track Rule 46 also addresses gib wear, centerbowl clearance, and column plate wear

25 Common Friction Casting (Wedge) Designs 25

26 26 Worn Out Friction Castings (Wedges)

27 Ride Control Design 27 > 1 13/16 (~1 ¾ ) Condemnable Per Rule 46

28 Barber Design 28 > ¾ Generally Condemnable Per Rule 46 (Check Rule for exceptions!)

29 Barber Variable Damped Trucks Allowable Wedge Rise AAR Rule Be Careful!!

30 C Wedge ½ Wedge Rise

31 Barber Gage 31 Ride Control Gage

32 Springs 32 ID

33 33

34 Spring Groupings 34

35 35 Count Springs; Verify Type; Verify Inner and Outer Springs; Check Free Height

36 36 AAR Designated Spring Groups

37 37

38 38 Right Side Left Side; Missing corner inner coils

39 39 Spring showing sign of fatigue/set

40 Checking Free Height 40

41 Broken Spring 41

42 42 Solid Spring Indicates Excessive Rock/Roll

43 43 Truck Frame Pedestal Bolster Swing Hanger Bushings Primary Suspension Tie Rod Side Bearings Secondary Suspension Spring Plank General Passenger Truck Components Equalizer Swing Hanger

44 44 LOAD PATH Secondary Suspension Truck Bolster Frame Primary Suspension Equalizer Spring Plank Basic GSI 70 Suspension

45 45 Equalizer Springs Primary Suspension Truck Frame Equalizer Bar

46 46 Secondary Suspension Spring Plank Equalizer Springs Primary Suspension

47 Air Spring Secondary Suspension Between Bolster and Car Body 47

48 Amfleet Passenger Car Trucks 48 Primary suspension at each journal Shock Ring

49 Light Rail Vehicle Suspension Air Spring Secondary Suspension Between Bolster and Frame 49 Note: vertical damper Primary suspension at each journal

50 Amtrak Superliner Car 50 Wagon Union Truck

51 Amtrak Superliner Car 51 Primary Suspension

52 Amtrak Superliner Car 52 Secondary Suspension

53 Locomotive Suspensions 53

54 54 Primary Suspension

55 55 Secondary Suspension

56 56 Genesis Trucks

57 Dampers 57 Mostly hydraulic or friction style used on passenger cars Used to absorb lateral and vertical shocks from track Dissipates Energy from spring suspension Restores ride quality Courtesy Koni Company

58 Hydraulic Dampers Construction 58 Courtesy Koni Company

59 59 Typical Transit Car Vertical Suspension Showing Hydraulic Damper in Parallel with Air Spring

60 Friction Dampers 60 Courtesy Vibratech Company

61 Dampers Inspection Items 61

62 Lateral Suspension 62

63 Lateral Suspension 63 3 Piece trucks have relatively poor lateral suspension characteristics, relying primarily on shear stiffness of load springs and friction damping due to wedge motion Passenger/locomotive trucks have improved lateral suspension relying on both swing motion of the bolsters, shear of the secondary springs, and bump stops. In addition, lateral shock dampers are used.

64 64 Bolster & Lateral Bump Stops 1 Nominal Bolster Stop to Body clearance; +1/4, -0 tolerance Lateral Bump Stops

65 Lateral Damper Air Spring 65 Side Bearing Lateral Secondary Suspension Elements of Typical Transit Car Showing Damper and Air Spring.

66 Yaw/Warp Suspension 66 Warp Stiffness Sideframe to Bolster Warp/Yaw Stiffness Wheelset to Sideframe

67 Yaw/Warp Suspension 67 Warp Stiffness Sideframe to Bolster

68 Yaw/Warp Suspension 68 Warp/Yaw Stiffness Wheelset to Sideframe

69 Yaw/Warp Suspension 69 Yaw/Warp Stiffness influences two primary responses Hunting (high speed stability) Truck Warp (Curving) Freight Cars depend on the friction wedge system for warp stiffness Passenger cars are normally rigid frame possessing high warp stiffness, but typically possess lower yaw stiffness

70 70 Truck Hunting Lateral Instability 90 Degrees Wedges Help to Keep Truck Square

71 71 Hunting Oscillation of a Tapered (Conical) Wheelset

72 72

73 Truck Stable Remains Square Truck Hunting Bolster Sideframe Out of Square 73 Friction wedges provide squaring force Friction wedges worn providing no squaring force

74 Hunting Speed Response Hunting Severity 74 Critical Speed for Hunting Prone Cars BH, ET, EF, EG Lateral G s Critical Speed for Most Cars Speed MPH

75 75

76 Truck Warp Restraint Ideally, a truck should remain Square during curving to allow radial alignment of wheelsets with curve

77 77

78 78

79 79

80 Barber Frame Brace Truck 80 Frame Bracing increases the warp stiffness of the truck improving both high speed stability and curving.

81 81 The End Truck Suspension Basics