Post on 24-Feb-2016
description
63 Tiger Cub - Clutch
Will, Adam, Robert, and Jack
What is a clutch?
• A clutch is a device used in machines to transmit power from the engine to the transmission
• It can be engaged to allow the engine and transmission to spin at the same speed or disengaged to allow them to spin at different speeds (thus allowing the rider to shift gears)
• Wet vs. dry clutch?
Why do we need a clutch?
• The clutch allows for a smoother shift from gear to gear
• Without a clutch the transmission would wear down over time
• Without a clutch, the only way to stop the wheels from spinning would be to turn off the engine (because otherwise whenever the engine spins the wheels would too)
Clutch Parts
Clutch Parts
Backing Plate
• Backing plate, rebound rubber, drive rubber, spider, lock washer, centre, centre driving cup, backing plate pin, sprocket bearing ball, sprocket bearing ring
Sprocket and Housing
• Double sprockets
Driven Plates
• Steel• Lugs on inside• Engage with the
engine
Driving Plates
• Pads = cork• Lugs on outside• Engage with the
transmission
Pressure Plate• Presses plates together to engage clutch• Pushed up by clutch operating rod to
disengage clutch and allow rider to shift
Spring Cups
Pressure Springs
• Press on pressure plate to engage clutch
Pressure Spring Nuts
Sprocket and Primary Chain
• Why double chain?– Innovation double
chain is more durable, single chain caused the sprockets to wear down/break
Clutch Lever
Clutch Cable
Clutch Operating Rod
How It Works
• When the clutch is engaged, the driven and driving plates are pressed together by the pressure plate and springs and spin at the same speed
• When the clutch lever is pulled, the clutch operating rod pushes up on the pressure plate, disengaging the clutch and allowing the engine and transmission to spin at different speeds, thus allowing the rider to shift gears
Friction - Why multiple plates?
• Having multiple plates increases the friction, thus reducing the slippage
• The greater the friction, the greater the torque that the clutch can handle without slipping
How much force is applied by the springs?
• Gear ratio: 19/48• Length of spring: 1.53 in. = .1275 ft.• Length of spring after 20 lbs. applied = 1.324
in. = .1103 ft. • # of surfaces touching = 7• Coefficient of friction = 0.8 (cork on steel)• Diameter of clutch = 5.33 in. = .444 ft. • Clutch slips @ 50 ft.lbs.
How much force is applied by the springs?
• F = kx (spring)• F = uN (friction)• T = rF (torque)• Given a torque, we found compression in the
springs• If we assume a certain amount of compression
in the spring, we can find any torque