mechanical drives and power transmission training

1

Basic Mechanical Drives and Power Transmission Training

December 2007

2

Mechanical Drives/Power Transmission Training

The purpose of this presentation is to

provide a overview of industrial drives and their maintenance.

Gear Drives Belt Drives V-Belt Maintenance Chain Drives Sprocket and Roller Chain Maintenance

3

Gear Drives

December 2007

4


Gear Boxes

5


Types

Types Automotive transmissions Auxiliary transmissions Transfer cases Power takeoffs Marine gears Hydraulic drives Industrial transmissions Differentials

6


Gear Boxes

Series trains Planetary gearing Speed reducers

Base mountedShaft mounted

Speed increasers

7


Gears and Gear Boxes

A gear is a form of disc, or wheel, that has teeth around its periphery for the purpose of providing a positive drive by meshing the teeth with similar teeth on another gear or rack.

8


Right Angle Gear Drive

9


Spur Gears

10


Involute Curve

Cord

Base Circle

Circle involute

Circle

11


Pressure Angle

Pressure Angle

Pressure angle

Pressure angle

RotationLine of action

14 ½ ° 20°

Direction of tooth to

tooth push

12


Pitch Diameter and Center Distance

2

21 DDC

221 DCD

Center Distance C

Pitch Diameter D1

Pitch Diameter D2

122 DCD

13


Circular/Diametrical Pitch

Circular Pitch

3.1416”

1 2 3 4 5 6 7 8 9 10

14


Names of Gear Parts

Clearance

Pitch Circle

Addendum

Pitch Circle

DedendumWhole depth

Working depth

ThicknessCircular

pitchPitch Line

Addendum

Dedendum Whole depth

Thickness

Circular pitch

15


Backlash

Backlash

Pitch Line

16


Other Gear Types

Bevel and Miter Helical Worm Herringbone

17


Bevel and Miter Gear

Shaft Angle

18


Helical

Helix angle

19


Worm Gear

20


Herringbone Gear

21


Gear Damage

Vibration Frequency Component – gear mesh Normal profile

22


Troubleshooting

Inappropriate bidirectional operation Gear overload Misalignment Poor maintenance Induced misalignment Visual inspection

23


Wear patterns

Normal

Abrasives in lubricating oil

24


Pattern caused by corrosive attack on gear teeth

Pitting caused by gear overloading

25

December 2007 Belt Drives

Belt Drives

26


Introduction

DescriptionBasic Components

Load carrying sectionRubber compression sectionCover

27


Belt Drives

Belt drives are used to transmit power between a drive unit and a driven unit

Drive Motor

Driven Unit

28


Belts

The size of the belt must match the sheave size. if they do not match, then the belt will not make proper contact with the sheave and will decrease the amount of load it can transmit.

A

AB

B

29


Belt Selection

Standard V-Belt Cogged Belt

Joined V-Belt Positive Drive Belt

30


Sheaves

31


Shaft Speed

erave_diametDriven_she

_rpmdriveshaftncheseDiameterIDriveSheavt_rpmDrivenShaf

12 inch dia.

6 in dia.

1800 rpm

DriveDriven

rpm

32


Driven Sheave Diameter

ft_rpmDriven_sha

_rpmdriveshaftncheseDiameterIDriveSheavveDiameterDrivenShea

___ inch dia.

6 in dia.

1800 rpm

DriveDriven

900 rpm

33


Belt Length

12 inch dia.

6 in dia.

DriveDriven

35 inches

2centercenter_to_2

3.14meterdriven_dia2

3.14eterdrive_diamhBelt_lengt

34


Belt Speed

12

14.3 rpmdiameterFPM

12 inch dia.

6 in dia.

1800 rpm

DriveDriven

900 rpm

35

December 2007

V-Belt Maintenance

36


Belt Maintenance

Routine maintenance is essential if a belt drive is to operate properly

37


Belt Maintenance

Never force belt onto sheave Belt should not ride on bottom of sheave. Check belt condition Belt alignment Tension Inspect sheaves and shafts Belt stretch

38


How to Read V-belt Numbers

39


Classic Cog V-belts AX-BX-CX-DX

40


D-V Wedge Belts 3VX-5VX-8V

41


Classic V-belts A-B-C-D-E

42


V-belt Inspection

Slapping Squealing Check belt

condition Tightness Tension

43


V-belt Sidewall Wear

44


V-belt Worn Cover/soft or Swollen

45


V-belt Slips, Squeals (Spin Burn)

46


V-belt Underside Cracked

47


V-Belt Cover Split / Missing Cogs Belts pried upon

Foreign objects Excessive heat Sheave too small Sheave misaligned Improper storage

48


Sheave Inspection

Sheave groves must be

like this

not this

Dished out

49


Sheave Inspection

5V

10.01-16.0O.D.

40 deg

Under 10.0O.D.

38 deg

Over 16.0O.D.42

deg

Example sheave gauge

50


Alignment

51


Types of Misalignment

Angular Misalignment

Parallel Misalignment

52


Shaft Alignment

Cord tied to shaft

Cord touching sheaves at points indicated by arrows

53


Tensioning V-belts Drives

Too tight

Too loose

Slight bow

54


Check Tension

55


Preventative Maintenance

Check belt condition Check belt tension Identify sources of contamination Check sheave alignment Check sheave wear

56

December 2007

Chain Drives

57


Introduction

DescriptionTypes of links

Self forming teethExtended Pin

58


Introduction

DRIVEN ROLL

DRIVE GEAR BOX

Chain Pitch

59


Chain Drive

60


Advantages No slippage More compact than belt Good for slow speeds Easier to install Not subject to deterioration Operates under wet conditions Less adjustment required Can drive several shafts Less costly than gear drives

61


Disadvantages Cannot be used where drive must slip Cannot except misalignment Noisy Causes vibration Needs frequent lubrication Small load capacity Shorter Service Live

62


Chain Drive Principles

Drive chain

Drive Sprocket

Sprocket

63


Shaft Speed

teethcket_#DrivenSpro

_rpmdriveshaftteethket_#DriveSproct_rpmDrivenShaf

12 T 6 T

1800 rpm

DriveDriven

rpm

64


Chain Length Calculation

2nterCenterToCe2

PitchcketTeethDrivenSpro2

PitchketTeethDriveSprochChainLengt

12 T 6 T

DriveDriven

35 inches

40 Chain

65


Chain Speed

12

rpmpitchteethFPM

12 T 6 T

1800 rpm

DriveDriven

900 rpm

40 Chain

66


Some Chain Drive Examples

Fork Lift Roller Conveyor

67

December 2007

Sprocket and Roller Chain Maintenance

68


Roller Chain

69


Pitch

70


Large Pitch Conveyor Chain

71


Chain Part Friction Areas

Major friction areas in red

72


Lubrication Methods

Hand Oiling Drop Lubrication Oil Bath Rotating Plate Forced Circulation

73


Example Application Large Roller Chain Multi-strand conveyor Large Roller Chain

74


Sprockets

75


Sprocket Classifications

76


Chain Drive Factors

Location of slack Chain wrap Vertical arrangement

77


Installation – Parallel Shafts

Level

Level

78


Installation

79


Installation - Sprockets

Straight edge or Straight string

Gap

80


Installation

81


Chain LengthThe following information is needed for an equation to find the chain length:

1. Number of teeth on the drive sprocket. 2. Number of teeth on the driven sprocket. 3. Center-to-center distance between the shafts. 4. The chain pitch in inches.

82


Chain Inspection Cleanliness Lubrication Signs of wear Flexibility Check chain stretch Physical damage

83


Chain Wear

WORN CHAIN

NEW CHAIN

SPROCKET

84


Sprocket Tooth Wear SPROCKETS INDICATE

WEAR HERE

85


Preventive Maintenance

Inspect for wear Lubricate Check chain sag Set tension Inspect sprockets

86


Summary and Quiz

Review Objectives Question and Answer Session

mechanical drives and power transmission training

Documents