Describe, using a brake-circuit sketch (and Pascal’s principle), how braking force gets multiplied in a typical automobile, from brake-pedal to brake-pads. Show a schematic to obtain a 36X force multiplier (ie Output force of 360 lb) through a mechanical advantage of brake lever (4X) and remaining through hydraulic force multiplication, for an input force of 10 lb at the master cylinder.

DESIGN OF CLUTCHES AND BRAKES – COURSE QUESTIONS

1. Describe, using a brake-circuit sketch (and Pascal’s principle), how braking force gets multiplied in a typical automobile, from brake-pedal to brake-pads. Show a schematic to obtain a 36X force multiplier (ie Output force of 360 lb) through a mechanical advantage of brake lever (4X) and remaining through hydraulic force multiplication, for an input force of 10 lb at the master cylinder.

2. Sketch a single-disk dry clutch, show its MAIN components, and label them. Clearly indicate Driving and Driven components (you can use different colour pens for Driving and driven side)

3. Why do clutch plates have coiled springs and splines?

4. Compare and contrast a dry and wet-clutch system in terms of clutch life, power transmission capability, size etc.).

5. Sketch a schematic of a Rear Wheel driven automotive drivetrain (manual transmission system), showing main mechanical elements (Engine, clutch, gear box, drive shafts and rear wheels).

6. A single-disk dry clutch (Similar to Fig 18.2), is to be designed for use with an engine with a maximum torque of 350 N m. A friction material is to be used for which design values are f = 0.25 and pmax = 350 kPa. A safety factor of 1.4 should be used with respect to slippage at full engine torque, and the outside diameter should be as small as possible. Determine appropriate values of r1, r2 , and F.

7. A Clutch system is to be designed to transmit a 400 ft-lb of torque, with a Margin of Safety of 1.6. A multi-plate clutch in an oil bath is found to be suitable for this application. The outer disk diameter is to be limited to a maximum of 7.5 inch. Design data for molded friction material and steel disk is pmax = 200 psi and f = 0.08. Determine inner diameter of disks, clamping force and number of disks. Assume uniform rate of wear at interface (List necessary assumptions, make suitable sketch & label it, write conclusions).

8. Sketch and label schematic diagram of Drum Brake and compare its working with Disc Brakes. Ch 18 in book has good information on drum brakes.

9. Explain working of a Centrifugal clutch. Draw a labelled sketch. (Feel free to look up the information on internet).

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