Centrifugal Clutch

Centrifugal Clutch uses centrifugal force instead of spring force. This clutch is always in engaged position. And it does not have a clutch pedal to operate it. Centrifugal clutch is automatically operated with engine speed.

The vehicle can be stopped in gear without stalling (stop running) the engine. And also the gear can be started in any gear by pressing the accelerator pedal.

 

 

Working Principle

A centrifugal clutch works on centrifugal force. One side of clutch connected to the engine crankshaft and other side connected to gearbox shaft, chain, or belt.

As engine R.P.M. (Revolutions Per Minute) increases, weighted arms in the clutch swing outward and force the clutch to engage position.

The most common Centrifugal Clutches have friction pads or shoes radially mounted that engage the inside of the rim of the housing.

 

 

Working of Centrifugal Clutch

On the center shaft (Driving or input shaft) there are an assorted amount of extension springs, which connect to a clutch shoe. When the center shaft (Driving shaft) spins fast enough, the springs extend causing the clutch shoes to engage the friction face.

It can be compared to a drum brake in reverse order. The weighted arms force these disks together and engage the clutch and power transmitted.

When the engine shaft reaches a certain RPM (Revolutions Per Minute), the clutch activates, working almost like a continuously variable transmission. As the load increases the R.P.M. drops thereby disengaging the clutch and letting the RPM rise again and reengaging the clutch.

If tuned properly, the clutch will tend to keep the engine at or near the torque peak of the engine.

These results in a fair bit of waste heat, but over a broad range of speeds it is much more useful than a direct drive in many applications like mopeds and go-karts etc. Weaker spring or heavier shoes will cause the clutch to engage at a lower R.P.M. while a stronger spring or lighter shoes will cause the clutch to engage at a higher R.P.M.

 

 

Line Diagram

Line diagram of Centrifugal Clutch

 

 

Advantages

  • Centrifugal Clutch has less maintenance.
  • It is not expensive.
  • It does not need clutch pedal because it’s automatic.
  • It helps to prevent the engine from stalling (stop running).

 

 

Disadvantages

  • Due to slipping and friction, There is a loss of power.
  • It does not transfer a high amount of power because Centrifugal clutch shoes slip in heavy load condition.
  • It causes overheating problems.
  • Its engagement and disengagements depend upon the speed of the driving shaft.

 

 

Applications

  • The centrifugal clutch is mainly used in mopeds and go-karts.
  • It is also used in mini bikes, chainsaw, and lawn mowers etc.
  • It is used in boats and paramotors to keep the engine running during stalling (stop running) and disengage loads during starting and idling.

 

 

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