University of South Florida Windscreen Wiper Mechanism Design Analysis Discussion

Windscreen wiper is essential for keeping the windscreen sufficiently clean for driver’s visibility specifically for modern high speed vehicles. The washer cleans the driver’s side of the windscreen whenever required. The wiper system must perform the following tasks.

(a)Efficient removal of dirt, water and snow.

(b)Operation in the temperature range of 243 K to 353 K.

(c)The ability to pass the stall and snow load test.

(d)A service life of around 1500 000 wipe cycles

(e)Resistance to corrosion from acid, alkalis and ozone.

For meeting the above requirements, proper design and manufacturing with good quality components are required for both the wiper and washer systems. The actual method of cleaning the screen by the blades can vary provided that the legally prescribed area of the screen is cleaned. Wiper systems generally use two wipe speeds to suit the driving conditions and also an intermittent wipe facility is incorporated. The layout of a typical wiper system is shown in Figure 1. A worm on the armature shaft drives a worm wheel connected to a crank to provide the reciprocating action needed to oscillate the wiper blades. The gear mechanism provides the speed reduction and the torque increase required to drive the wiper blades.

Questions:

You are instructed to answer the following tasks based on the understanding on machine design and standards. A report of about 1500 words is expected.

Task A

1.Collect the specifications of various mechanical components that you need to design the windshield wiper mechanism design.

2.Identify the material you are going to select for each mechanical component .Justify your answer with mechanical properties.

3.Explain the power transmission system of the wiper mechanism with diagrams

Task B

4.Explain the codes and standards applicable for the various mechanical components you need to refer for the design.

5.Use the shaft design procedures for evaluating the strength parameters .How will you decide the diameter of the shaft? Assume data and prove analytically.

Task C

6.Use the gear design procedures for analyzing the gear box of the system. How will you check the static, dynamic and wear load of the gears? Assume data and prove analytically.

7.Collect the details of rubber wiper blade for analysis. Using the data prove analytically the energy transfer involved during wiping.

Task D

8.Explain how static and variable loadings affect the working of the system.

9.What do you understand by the term design for robustness? How will you modify the design of wiper mechanism for robustness?

Answer to be submitted in the attached word file