clutch, mt, amt
Post on 21-Sep-2014
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TRANSCRIPT
K Ganesh Babu
The Automotive Research Association of India, Pune
Introduction
Transmission Types
Manual
Automated Manual
Automatic
Continuously variable
Dual Clutch
Propeller Shaft
Universal joints
Final drive
Differential
Transmission Trends
The Automotive Research Association of India, Pune
The Automotive Research Association of India, Pune
It is used to transmit engine torque to the driving wheels to drive the vehicle on the road.
The Automotive Research Association of India, Pune
The Automotive Research Association of India, Pune
To provide for disconnecting the engine from the driving wheels
When engine is running , connect the driving wheels to engine smoothly without shock
Leverage between engine and driving wheels to be varied
Turn the drive to 900
Enable the driving wheels to rotate at different speeds.
Provide relative movement between engine and driving wheels
The Automotive Research Association of India, Pune
The Automotive Research Association of India, Pune
The Automotive Research Association of India, Pune
The Automotive Research Association of India, Pune
The Automotive Research Association of India, Pune
Manual Transmission (MT) – Conventional Definition
Moving away from rest – dry plate clutch
Achieving ratio change – external cylindrical gears
Power interruption
Mechanism for ratio change
▪ Positively engaged shifting dogs, synchronised (passenger cars and commercial vehicles)
▪ Positively engaged non-synchronised (motorcycles)
Control of ratio change – manual
When a driver wants to change from one gear to another in a standard stick-shift car, he first presses down the clutch pedal
This operates a single clutch, which disconnects the engine from the gearbox and interrupts power flow to the transmission
Then the driver uses the stick shift to select a new gear, a process that involves moving a toothed collar from one gear wheel to another gear wheel of a different size
Devices called synchronizers match the gears before they are engaged to prevent grinding
Once the new gear is engaged, the driver releases the clutch pedal, which re-connects the engine to the gearbox and transmits power to the wheels.
The Automotive Research Association of India, Pune
The Automotive Research Association of India, Pune
Clutch is used to disengage and engage the engine with rest of the transmission systems.
To disengage while starting the engine and while changing gear ratio.
To engage after starting of the engine and gear shift operation.
The Automotive Research Association of India, Pune
Transmit maximum torque of the engine.
Engage gradually to avoid sudden jerks.
Dissipate maximum amount of heat.
Dynamically balanced.
Damp the vibrations and noise.
As small as possible.
Easy to operate.
The Automotive Research Association of India, Pune
The Automotive Research Association of India, Pune
Cone clutch
Flat Plate clutch Dry or Wet type clutch No. of friction plates
(Single or Multiple) Actuation mode (Cable or
Hydraulic) Actuation spring (Helical or
Diaphragm) Centrifugal clutch
The Automotive Research Association of India, Pune
Flywheel
Clutch Cover Assembly
Clutch Disc Assembly
Flywheel also acts as a driving member
Pressure plate is connected to clutch cover assembly.
Clutch Cover assembly is bolted to the flywheel.
Clutch springs placed between Pressure plate & Cover plate, press the Pressure plate against the clutch plate.
Thus Clutch plate is squeezed between Flywheel & Pressure plate.
The Automotive Research Association of India, Pune
The Automotive Research Association of India, Pune
Components:
1. Flywheel2. Friction Facing3. Cover Stamping4. Pressure Plate5. Cushion Plate Rivets with Clutch
Plate6. Diaphragm Spring7. Damper8. Transmission Shaft9. Actuation Lever10. Splined Shaft11. Pilot bearing rest12. Ring fulcrum (for Diaphragm Spring)13. Drive Strap/Clip/Lock14. Clutch Cover Assembly Bolted with
flywheel
The Automotive Research Association of India, Pune
Location: b/w Flywheel &Clutch Cover Assembly.
Mounting: over splinedtransmission shaft.
Friction facings riveted tocushioning plates
Cushion plates riveted toclutch plate and retainingplate
Torsion springs mountedon splined hub
It is mounted over cushion plate.
It helps in generating friction force
Grooves are created on the surface offacing in order to eradicate the problemof friction disk sticking to flywheel.
Graphite Particles (they are inexpensive,increase wear rate, increase heatresistance)
Sintered/Ceramic Metals (high powertransmission and good heat resistance)
Fibrous Reinforcements: Fiberglass,Acrylics, Rayons, Aramids, Mineral Fiber& Cotton Fiber.
The Automotive Research Association of India, Pune
Cushion is a wave shapedcomponent of the sheet of 0.5mm thickness.
It is riveted to friction facing andclutch plate (disc plate) as well.
Allowable compression is 1 to 2mm
The Automotive Research Association of India, Pune
DiscPlate / Clutch Plate Riveted with cushions. It faces the flywheel
side. Disc Plate and Retainer Plate are riveted
together using stop pins.
RetainerPlate It faces the transmission shaft side. Disc plate and retainer plates have voids to
accommodate dampers.
The Automotive Research Association of India, Pune
Hub is splined and is attached to Hub plate.
Hub is mounted on a splined transmissionshaft and slides over the same at the timeof engagement and disengagement.
Hub plate is placed between disc (clutch)plate and retainer plate
Hub Plate had voids to accommodatedampers (like retainer and disc plate)
Hub plate possesses relative motion (w.r.t.retainer & disc plate) during damping thevibrations. Hence transmits less vibrationsto transmission shaft. So a smooth drive
The Automotive Research Association of India, Pune
Damper is strategically placed in b/wdisc plate, retainer plate and hub plate,in such a manner that one face remainsin contact with hub plate and anotherwith retainer & disc (clutch) plate.
Jerks from flywheel are absorbed bythese dampers and less jerks aretransmitted to transmission shaft.
Oil Hardened and Tempered Steel Wire
The Automotive Research Association of India, Pune
Clutch Cover Assemblycomprises of pressureplate, diaphragm springclutch cover, fulcrumrings and strap platesetc..
Mounting: It is boltedwith the flywheel andprovides extra frictionalsurface for the Clutchdisc to transmit power.
The Automotive Research Association of India, Pune
Flattened on one face to provide frictionsurface for clutch disc. And on other face,fulcrum is made for actuation spring.
Its is held with clutch cover using drivestraps and clips and is actuated by eitherDiaphragm spring or Helical spring.
Pressure plate also rotates as engine’sspeed.
CI is used for better heat dissipationcapacity and wear resistance.
The minimum travel of the pressure plateshould be the compression length ofcushion plate
The Automotive Research Association of India, Pune
Actuation spring holds the pressure
plate with Clutch disc in normal
condition.
During actuation it disengages the
pressure plate with friction disc,
hence cuts off the power flow.
Types: Diaphragm Spring / Helical
Spring.
The Automotive Research Association of India, Pune
Diaphragm spring loaded assembly occupies less axial space, even the
cooling fins can be mounted with the use of diaphragm spring.
During initial stage of clutch facing wear, clamp load increases.
Continued wear eventually results in fall of clamp load, once the clamp load
gets over to the hump.
Heat treatment Process:50CrV4 Quenching at 880˚C Tempering at 12 stages
The Automotive Research Association of India, Pune
Drive Straps used to hold pressure plate with
the clutch cover
Cover Stamping It contacts the diaphragm
spring at a specified fulcrumdiameter. Fulcrum elementsmay be the wire rings up andbelow the diaphragm springand riveted to the coverstamping.
The Automotive Research Association of India, Pune
Clutch is always is in engaged state.
It can be disengaged by pressing of Clutch pedal.
Disengagement is effected by non – contact of Clutch plate both with Flywheel face & Pressure plate face.
Frictional heat is dissipated by openings present in Clutch housing & Cover
The Automotive Research Association of India, Pune
The Automotive Research Association of India, Pune
The Automotive Research Association of India, Pune
Gear box varies the leverage (speed ratio & hence torque ratio) between the engine & driving wheels.
It is located between Clutch & Propeller shaft.
It is provided with either 4 speed or 5 speed ratios or more depending on design.
Gear ratio is varied by Gear shift lever.
The Automotive Research Association of India, Pune
The Automotive Research Association of India, Pune
Constant mesh
Sliding mesh
Synchro mesh
The Automotive Research Association of India, Pune
The Automotive Research Association of India, Pune
5-speed Single layshaft 5-speed, intermediate shaft off input shaft
The Automotive Research Association of India, Pune
The Automotive Research Association of India, Pune
Implications of 6-speed Transmissions
Packaging constraints
▪ Gearbox length
▪ Distance from input shaft to final drive shaft
The trend began among versions with the highest performance, or premium brand
High Performance Diesel require high ratio spread
The trend is spreading rapidly:
Virtually every European and Japanese OEM now offers a 6-speed manual gearbox in at least some of its models
VW has announced that it will fit only 6-speed gearboxes across its range in the near future for all their European cars
6-speed, twin-layshaft 6-speed, intermediate shaft off layshaft
The Automotive Research Association of India, Pune
56123/4
4
FD
R
33 4 R
5 6 1 2
FD
1
The Automotive Research Association of India, Pune
Manual Transmission (MT) – Discussion of different layouts
Single layshaft design cheapest and simplest
Move from 5 to 6-speed inevitable, hence increased axial packaging constraints
Some single layshaft 6-speed transmissions made, but difficult to package, leads to narrow face widths, poor axial contact ratio etc.
options on reducing axial packaging identified
▪ Intermediate shaft off input shaft
▪ Twin layshaft, twin final drive pinion
Collars are moved by forks.
Forks are controlled by three shift rods, engaged by shift lever.
Movement of the shift lever causes the movement of collars towards required gear for engagement with main shaft
Sequential shifting for two wheelers
The Automotive Research Association of India, Pune
A device used to bring two adjacent members to the same speed before allowing the sleeve to engage them
The two elements are friction clutch and toothed clutch.
Lock the positive engagement until speeds are synchronized
Establish the positive engagement and power flow.
The Automotive Research Association of India, Pune
Synchronizer is splined on the shaft
Gear is running freely with NRB on shaft
Cone on the gear (blue) fits into cone-shaped area in the collar.
Friction between the cone and collar synchronize the collar & gear.
The outer portion of the collar (sleeve) then slides so that the dogteeth engage the gear.
The Automotive Research Association of India, Pune
Synchronizer cone with selector teeth
Blocker ring
SleeveBlocker ring
Strut
HubSpring
Spring
The Automotive Research Association of India, Pune
The Automotive Research Association of India, Pune
The Automotive Research Association of India, Pune
The Automotive Research Association of India, Pune
The Automotive Research Association of India, Pune
The Automotive Research Association of India, Pune
Transmission cost to weight ratio
The Automotive Research Association of India, Pune
Source: Lechner
The Automotive Research Association of India, Pune
Prospects for commercial success
▪ Cheap to make
▪ Durable, efficient
▪ Easy to install
▪ Established in marketplace and with manufacturing infrastructure
▪ Gives control to the driver
▪ But driver comfort an issue with increasing traffic density
▪ Hence automation must be considered
The Automotive Research Association of India, Pune
Automation of Clutch and Gear shifting operations
Elimination of Clutch Pedal
Modification of Gear Shifting lever
Minimum modifications in manual transmission
The Automotive Research Association of India, Pune
Clutch Actuator
Selection and Shifting Actuator
Automation of Clutch operation and Gear shifting.
Clutch slip control during starting
Hill start aid system which will assist the driver in hold and move the vehicle in hill slope
Necessary fail safe systems such as sudden shifting from higher gear to lowest gear and vice versa
The Automotive Research Association of India, Pune
Reduced driver effort
Improved Clutch life
Utilization of existing manufacturing facilities for manual transmission
Lower production cost than automatic transmissions
Higher efficiency than automatic transmissions
The Automotive Research Association of India, Pune
The Automotive Research Association of India, Pune
Gear Shift Actuator AMTClutch ActuatorSource: Luk
Engine Torque
Clutch Pedal Force
The Automotive Research Association of India, Pune
H - Gate
The Automotive Research Association of India, Pune
Driver
ECUVehicle Speed
Clutch Actuator
Transmission Actuator
Vehicle Transmission Clutch
Selector lever Traffic Conditions
Signal
Signal
Intention
Drive TorqueActuation
The Automotive Research Association of India, Pune
Pulse Signal Conditioner
Analog Signal Conditioner
Contact Point
Signal input
circuit
ECU
Power Unit
Multiplexer
Motor Drive Circuit
Indicator Drive Circuit
Starter Inhibitor
Vehicle Speed
Input Shaft RPM
Clutch Stroke
Selector lever
Gear Position
Transmission Actuator
Clutch Actuator
Indicator
Starter
Engine Start
Starter should be operated only when the gear is in neutral position
When engine is not running and in power on, ECU will disengage clutch
When engine speed exceeds a specified rpm, ECU engages clutch gradually
The Automotive Research Association of India, Pune
Vehicle Start
On pressing the accelerator pedal, ECU controls the clutch actuator travel and clutch engagement
Gear Change
While engaging the clutch after gear shift, the ECU determines clutch actuator travel based on shifted gear position and accelerator pedal stroke
The Automotive Research Association of India, Pune
Clutch disengagement
While gear shifting and when accelerator pedal is released, if the vehicle speed is lower than a set speed for select gear position, the ECU disengages clutch
The Automotive Research Association of India, Pune
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