Top Banner

Click here to load reader

Automotive Drivetrains

Feb 20, 2016




Automotive Drivetrains. CLUTCHES. Purpose. To connect and disconnect engine power flow to the transmission at the will of the driver. Clutch System. Clutch systems are used to disengage the engine from the road - PowerPoint PPT Presentation

  • Automotive DrivetrainsCLUTCHES

  • Purpose

    To connect and disconnect engine power flow to the transmission at the will of the driver.

  • Clutch systems are used to disengage the engine from the road When the clutch pedal is depressed, the clutch (and transmission) is disengaged from the engine Clutch System

  • With your foot off of the pedal, the clutch is engaged to the engine.The pressure plate holds the clutch against the flywheel, allowing power to travel through the clutch to the input shaft of the transmission ...Clutch SystemThe engine power will transfer through the clutch to the road

  • Flywheel: Transfers engine power to the clutch Input shaft: Transfers power from clutch to the transmission Clutch Disk (clutch): Splined to input shaft; transfers power from engine to the input shaftPressure Plate Assembly: Spring pressure tightly holds the clutch to the flywheelSystem Components

  • Components cont:Release Bearing (throw-out bearing): Connected through linkage or hydraulics to the clutch pedal; Provides a way for the pressure plate to release pressure on the clutch Pilot Bearing (bushing) : Mounted in the tail of the crankshaft. Stabilizes the input shaft. Not always used for FWD.Clutch Fork (if applicable): Slides the release bearing into and away from the pressure plate assembly

  • Components cont:Clutch Linkage (or hydraulic plumbing): Allows the driver to operate the clutch fork Clutch (bell-housing) Housing: Encloses the clutch assemblyMay be integral with the transmission or removable

  • Mounted on the rear of the crankshaftActs as balancer for engineAdds inertia to the rotating crankshaftProvides a surface for the clutch to contactUsually surrounded by a ring gear for electric starter operation Clutch Components - Flywheel

  • Usually constructed of nodular cast iron which has a high graphite contentThe graphite helps lubricate engagement of the clutchMay also be constructed from cold rolled steelFlywheel Construction

  • Dual-mass FlywheelThe flywheel hub and clutch mating area are two separate componentsSprings are used to dampen engine and clutch engagement oscillations

  • Dual-mass Flywheel

  • Run-out measured with a dial indicatorParallelism straight-edge & feeler gaugeThickness micrometer or dial indicator

    Flywheel Measurements

  • Projects from the front of the transmissionUsually has a pilot which rides in a bearing or bushing in the end of the crankshaftThe clutch disc is splined to the clutch shaftClutch ComponentsInput (clutch) shaft

  • Clutch Components Clutch Disc

    Is squeezed between the flywheel and the pressure plateTransmits power from the engine crankshaft to the transmission input shaft

  • Clutch Disc ConstructionFacing manufactured with frictional material (may contain asbestos)

    Other surface materials include:


  • Clutch Disc Types Rigid - used primarily for industrial/racing applications.

    Flexible - most common, everything from grandmas cruiser to street/strip racing.

  • Flexible Clutch DiscHub flange - in direct contact with the input shaftFriction ring - in direct contact with the flywheel/pressure plate.

  • Flexible Clutch DiscClutch facing - friction materialmarcel springs - facing dampenerTorsional springs - further dampening for clutch applicationStop pins - limits the torsional springs travelRivets -fastens the facing material to marcel (springs)

  • Squeezes clutch disc onto flywheelCan be engaged or disengagedActs like a spring-loaded clampClutch ComponentsPressure Plate (clutch cover)

  • Pressure Plate - TypesBelleville/diaphragm-type Spring: uses a cone-shaped diaphragm spring for clamping force. Multiple-Coil Springs: DUGH!Semi-centrifugal: clamping force increases as rotational (centrifugal) force increases

  • Belleville/diaphragm Spring:

  • Spring-type Pressure Plate

  • Benefits and Disadvantages:Belleville/diaphragm type:cost effectiveuniform engagementlimited spring pressureSpring:unlimited pressure capabilitiesas springs wear, pressure may become inconsistent

  • Operated by the clutch linkagePresses against the pressure plate to release the clutchClutch ComponentsRelease (throw-out) bearing

  • Clutch ComponentsPilot Bearing (bushing)Installed (pressed) into a machined bore in the end of the crankshaft or flywheelMay be a bushing, ball-bearing or roller-bearing

  • Clutch linkage MechanicalLinkage-type

  • Clutch linkage MechanicalCable-type

  • Clutch linkage HydraulicMost Commonly used today

  • Hydraulic Clutch Master

  • Hydraulic Clutch Slave

  • Hydraulic Clutch SlaveConcentric-type

  • Dual-clutch TransmissionEssentially an automatic manual transmissionDelivered to the mainstream by Volkswagen now being used/developed by most mfg. Eliminates the power sucking torque-converter of an automatic transmission

  • Dual-clutch TransmissionUtilizes two input shafts one inside of the otherEach input shaft will have a dedicated clutch or clutch pack splined to it. A processor (computer) will engage one or the other clutches (or neither for neutral.)

  • Dual-clutch TransmissionMay use a wet or dry clutch-pack

  • Dual-clutch Transmissionor conventional clutch disc design

  • Dual-clutch TransmissionEach of the input-shafts controls half of the transmissions gear-sets

  • Dual-clutch Transmission