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Power Transmission

Suresh Bhakta Shrestha

Asst. Professor & In-charge

Department of MechanicalEngineering

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Clutches

Requirements(1)Torque transmission(2)Gradual engagement

(3)Heat dissipation

(4)Dynamic balancing

(5)Vibration damping

(6)Size

(7)Inertia

(8)Clutch free pedal play

(9)Ease of operation

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Principle of Friction Clutch

Figure 1: Principle of Friction Clutch

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Factors Affecting ClutchOperation

TABLE 1: COEFFICIENTS OF FRICTION

FOR CLUTCH FACING MATERIALS

S.No. Material Coefficient of friction

1.2.3.4.

LeatherCorkCotton FabricAsbestos-base materials

0.270.370.4-0.50.35-0.4

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Dry Friction Clutches

Figure 2: Cone Clutch

TYPES

Cone clutch

Single plate clutch

Multiplate clutch

Semi-centrifugal clutch

Centrifugal clutch

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Single Plate Clutch

Figure 3: Single P late Clutch

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Single Plate Clutch

Figure 4: Simplified diagram show ing the

working of Single P late Clutch

Figure 5: Single P late Clutch forTata Truck

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Multiplate Clutch

Figure 6: Multiplate Clutch

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Transmission

Functions

1) To provide a means tovary the leverage or

torque ratio

2) To provide a neutralposition

3) To provide a means toback the car

Necessity

(a) Variation ofresistance to the

vehicle motion atvarious speeds.

(b) Variation of tractiveeffort of the vehicle

available at variousspeeds.

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Resistance to Vehicle Motion

Speed

R

esistance

TotalR

esistan

ce

Miscellaneous Resistance

Gradient ResistanceWin

dResis

tance

Figure 7: Various resistancesto the vehicle motion

Speed

TotalR

esistance

Figure 8: Total resistance to vehicleMotion at different gradients

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Resistance to Vehicle Motion

Speed

Tracti

veEffort&

Total

Resistance

1

2

3

Figure 10: Superimposing thetotal resistance and tractiveeffort curves for different gears

Speed

Tracti

veEffort

1

2

3

Figure 9: Tractive effort curvesfor different gradient

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Sliding Mesh Gear Box

Figure 10: Sliding Mesh Gear Box

(gears in neutral)

Figure 11: Four Speed Forward only

Sliding Mesh Gear Box(gears in neutral)

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Constant Mesh Gear Box

Figure 12: Constant Mesh Gear Box

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Synchromesh Gear Box

Figure 13: Synchromesh Gear Box

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Synchromesh Gear Box

Figure 14: Engagement of direct gear in aSynchromesh Gear Box

(a) Cones M1 and M2 mate to equalize speed(b) Member G1 pushed further to engage with dogs K1

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Modified Synchromesh Gear Box

Figure 15: Modified Synchromesh device(a) Just before engagement

(b) After engagement

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Selector Mechanism

Figure 16: Selector Mechanism Using gearlever on top of transmission

Figure 17: Gear Lever Knob for 5Forward speed & reverse gear box

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Interlocking Mechanism

Figure 18: Interlocking MechanismFigure 19: Interlocking MechanismShow ing movements of rods