Vacuum clutch, Clutch Slip

Introduction:

•Clutch utilizes the existing vacuum inside the engine intake manifold for disengaging the  

 clutch.

•A conventional type of clutch assisted by vacuum power

   

Construction details of vacuum clutch:

 

 

 

  •Vacuum reservoir connected to the intake manifold through non return valv

  •Vacuum cylinder connected to vacuum reservoir through solenoid- operating valve

  •Vacuum cylinder consists of a piston 

  •Piston rod is connected to clutch linkages 

  •Clutch pedal is not required 

  •Switch is provided in the gear lever

 

 Working of vacuum clutch:

 

 Clutch engage 

 •Switch remains open and the solenoid operated valve is in bottom position 

 •Atmosphere pressure acts on both sides of piston 

 •As there is no movement of piston rod, clutch is in engaged piston

 

 Clutch disengage 

 •When driver wants to disengage the clutch, presses the switch on the gear shifting lever 

 •The solenoid get energized there by causes pulling of the valve

 •Passage is open between the reservoir and the vacuum cylinder 

 •Vacuum enters into cylinder 

 •Piston moves back and the clutch linkages pushed back thus disengaging clutch

 

   Clutch Slip:

 

 •Clutch slip occurs when the driven disc (Clutch plate)  fails to rotate at the same speed as

  the driving member (fly wheel) when the clutch is fully engaged

 •This condition is due to worn clutch plate facings or grease or oil on the facings resulting in

   the clutch plate frictional coefficient to drop so that the clutch is unable to transmit the

   engine power properly  

 

 Causes of clutch slipping 

  • Worm linings 

  • Greasy or oil facings 

  • Improperly installed lining

  • Bending pedal mechanism 

  • Incorrect pedal adjustment

  • Weak pressure springs 

  • Incorrectly refitted floorboard or carpet 

  • Scored or warped faces of flywheel and pressure plate 

  • Lack of free play in clutch pedal

  • Worm splines on clutch shaft