Clucth and brake system

1. Centrifugal Clutch

2. Friction Material
• There are two types of friction materials in common use—asbestos-base and sintered metals.
• There are two types of asbestos friction materials—woven and moulded.
• A woven asbestos friction disk consists of asbestos fibre woven around brass, copper or zinc wires and
impregnated with rubber or asphalt. They have an endless circular weave, which increases the centrifugal
bursting strength.
• Moulded asbestos friction disks are prepared from the wet mixture of brass chips and asbestos, which is poured
into the mould and given the shape of the disk. The mixture is then heated and pressed for a specific curing time.
• There are two varieties of friction disks made from sintered metals—bronze-base and iron base, depending upon
the major constituent.

3. Friction Material

4. Clutch type Uniform Pressure Theory Uniform Wear Theory
Single Plate clutch
𝑷 =
𝝅𝒑
𝟒
𝑫𝟐
− 𝒅𝟐
𝑷 =
𝝅𝒑𝒂𝒅
𝟐
𝑫 − 𝒅
𝑴𝒕 =
𝝅𝝁𝒑
𝟏𝟐
𝑫𝟑
− 𝒅𝟑
𝑴𝒕 =
𝝅𝝁𝒑𝒂𝒅
𝟖
𝑫𝟐
− 𝒅𝟐
𝑴𝒕 =
𝝁𝑷 (𝑫𝟑
− 𝒅𝟑
)
𝟑 (𝑫𝟐 − 𝒅𝟐)
𝑴𝒕 =
𝝁𝑷 (𝑫 + 𝒅)
𝟒
Multi Plate Clutch
𝑷 =
𝝅𝒑
𝟒
𝑫𝟐
− 𝒅𝟐
𝑷 =
𝝅𝒑𝒂𝒅
𝟐
𝑫 − 𝒅
𝑴𝒕 =
𝝁𝑷𝒛 (𝑫𝟑
− 𝒅𝟑
)
𝟑 (𝑫𝟐 − 𝒅𝟐)
𝑴𝒕 =
𝝁𝑷𝒛 (𝑫 + 𝒅)
𝟒
Cone Clutch
𝑷 =
𝝅𝒑
𝟒
𝑫𝟐
− 𝒅𝟐
𝑷 =
𝝅𝒑𝒂𝒅
𝟐
𝑫 − 𝒅
𝑴𝒕 =
𝝅𝝁𝒑
𝟏𝟐 sin 𝜶
𝑫𝟑
− 𝒅𝟑
𝑴𝒕 =
𝝅𝝁𝒑𝒂𝒅
𝟖 sin 𝜶
𝑫𝟐
− 𝒅𝟐
𝑴𝒕 =
𝝁𝑷 (𝑫𝟑
− 𝒅𝟑
)
𝟑 sin 𝜶 (𝑫𝟐 − 𝒅𝟐)
𝑴𝒕 =
𝝁𝑷 (𝑫 + 𝒅)
𝟒 sin 𝜶
Centrifugal Clutch 𝑴𝒕 =
𝝁𝒎𝒓𝒈𝒓𝒅𝒛 (𝝎𝟐
𝟐
− 𝝎𝟏
𝟐
)
𝟏𝟎𝟎𝟎

6. Energy Equation

7. Block brake with short shoe

8. Block brake with short shoe

9. Block brake with short shoe

10. Block brake with short shoe

13. Problem: A double block brake is
shown in figure. The brake drum rotates
in a clockwise direction and the
actuating force is 500 N. The coefficient
of friction between the blocks and the
drum is 0.35. Calculate the torque
absorbing capacity of the brake.
Given:
P = 500N
µ = 0.35

15. Block brake with long shoe

16. Block brake with long shoe

17. Block brake with long shoe

20. Internal Expanding Brakes
Assumptions:

21. Internal Expanding Brakes