Power Transmission IOE

8/9/2019 Power Transmission IOE

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Sat a Nara an Shah

B.Sc. Mechanical Engineering (India)

MS in Manufacturing Engineering & Management (UK)


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The Beginning3

PedalDriver

Driver pushes on Pedal to move vehicle

He is more concern about smooth cruising i.e.. Best

output1 August 2010Er. Satya Narayan Shah


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Where Does the Force Come From?

En ine roduces some tor ue at a s eed

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Power- the rate at which work is done:

( )( )VelocityForcePower=

Power is Tor ue times Rotational S eed rotar

VF=

( )( )= SpeedRotationalTorquePower

=

1 August 2010Er. Satya Narayan Shah


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Where Does the Force Come From?

Power is conserved:5

vehicleaxletransengine PPPP ===

POWER IS ABSOLUTE Torque is relative (depends on gear ratio)

Ignoring Losses, of Course



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WHAT IS POWERTRAIN MATCHING ?

Selectin the ri ht en ine and earin for a iven a lication

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Not just performance, but giving the driver the expectedresponse to pedal inputs

Transmission shift schedules as fuel economy heavily impacted

in automotive applications.

Torque & Power shaping can give optimal performance for

a given set of gearing

Optimal gearing can make your car faster for no changes in

engine performance



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1 August 2010Er. Satya Narayan Shah7


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DRIVE TRAIN8



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POWER TRAIN SYSTEM 1 Front driveshaft (2) Output transfer

gearbox

(3) Transmission

(4) Upper driveshaft

(5) Torque converterupdrive transfer gears

orque conver er

(7) Engine

(8) Front differential

(10) Centre bearing

(11) Centre driveshaft

(13) Rear differential

(14) Rear final drives

1 August 20109 Er. Satya Narayan Shah


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Clutches

Connects /disconnects Engine

crankshaft to the transmission

(gear box)Change of gears can not be

smoot w en t e engine is irect y

connected with the transmission.ransm s e power o e roa

wheels smoothly

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Clutches Friction clutches are

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design to absorb energyduring slippage.

Virtually all vehicle

clutches are spring- . The torque transmission capacity of a

clutch can be estimated as,

where, Tc is the torque capacity, f is the

smcc nrfFT =

, c clutch, rm is the mean radius of the clutch,and ns is the number of friction surfaces.



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Clutch should

Consume minimum physical effort13

Be free from slipWearing surface should have long life

Be provided a suitable mechanism for damping of

vibration and elimination of noiseMain parts of clutch

Pressure plate:- It presses the driven plate against the

flywheel

Driven plate:- Is provided with annular facings and

spring cushioned hub1 August 2010Er. Satya Narayan Shah


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TypesofclutchThemostlyusedclutchisthefrictiontypeoffollowingtypes

Coneclutch:isonlyusedinthesynchromeshunitsofgearboxesandsometimesinepicyclical gearboxes

Single

plate

clutch:

Mostly

used

in

cars

and

trucksMultiplateclutch: Mostlyusedinmotorcycles,tractorsandmostl construction e ui ment. This t e of clutch is mostlusedwherehightorquetobetransmittedandlimitedspaceavailable

Centrifu alclutch

Freewheelclutchoronewayclutch

Bandtypeclutch

Electricalclutch

JumpClutch

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Advantages of fluid coupling

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transmission

imination o c utc p ate

Damping of the torsional vibration of thecrankshaft

During braking or down hill, the transmission

shocks are absorbed by the fluid



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Torque ConvertorTorque Convertor

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Tor ue ConvertorTor ue Convertor28



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Torque converter basic operation

Coupling stage:- Turbine is rotating at 90 % of the impeller33

spee

Fluid from the turbine strikes the convex side of the statorblade causing it to overrun

Coupling stage will be high when acceleration is not requiredand the equipment is cruising

At this oint the tor ue converter is actin like a fluid clutchThe impeller is rotating at engine speed, the turbine isstationary and the stator is locked against rotation

increasing vertex flowThe vertex flow strikes the turbine blades and diverted around



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Advantages of torque converter

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automatic transmission of the construction equipment

Smoothes out the transfer of engine torque to the

Acts as cushion between the engine and transmission

ampens v ra onsVirtually wear free



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Mechanical transmission

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e eng ne power s ransm e o e w ee s o

equipment through mechanical arrangements.

s ac eve y gear mec an sms n manua gear ox

Mostly this system is found in vehicles, trucks and light

Depending on the no. of gear for forward speeds and reversegear, power flows takes place in manual transmission system

ypes o gear oxe1. Sliding mesh type

2. Constant mesh type

3. Synchromesh type



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Mechanical transmission

Sliding mesh type:- is oldest and simplest, meshing of gears

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takes place by sliding of gears on each other. Consists of main

shaft, countershaft and idler gear shaft for reverse speedConstant mesh t e :- In this earbox all the ears mesh witheach other all the time. Gear changing is made easier byhelical gear. The primary shaft which carries the clutch is

s lined and carries a ear that mesh with ears on thelayshaft gear

Synchromesh gearbox:- Use synchromesh gear devices on the

equalizes their speed with readily and smoothly and thedevices used is synchronizer ring.



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The Planetary Gear combinations provide


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y p

as c operat ons Gear Reduction

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os t on- un gear s e ; ng gear - nput

Position-II Ring gear is held; Sun gear -input

Overdrive

Position-I Ring gear is held; Carrier-input

Position-II Sun gear is held; Carrier-input

Reverse

Position-I Carrier is held; Ring gear-input

Position-II Carrier is held; Sun gear-input

Direct Drive

Entire planetary unit works as single unit

At a time Two units input; one out put

Neutral

When no unit is held


Powershift Transmissions


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Powershift Transmissions

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power.

and b) planetary.



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Fig. 12.10a Countershaft Powershift Transmission


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(Hi Lo Shift)69


Hi Lo Powershift


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Hi Lo Powershift70

When neither clutch is engaged, transmission is in

neutral. When left clutch is engaged, output shaft turns

slower than input.

When right clutch is engaged, output shaft turns the

same speed as the input.

When both clutches are engaged, transmission is in

Park.


Fig. 12.10b Countershaft Powershift Transmission


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(Reverser)71


Reverser Powershift


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eve se owe s

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en neit er c utc is engage , transmission is

in neutral.,

opposite direction of the input.

turns the same direction as the input.

When both clutches are engaged, transmission

is in Park.



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meshing with the sun and the second meshing with

the ring gear.

May also include two sun and/or two ring gears.


Hydrostatic transmission system


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Basic ower train of h drostatic s stem

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Actuator

ng nepump valve Travel

motor

Swing motorBasic ower flow in h drostatic drive s stemLike in hydraulic excavator



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Power Transmission IOE

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