Automechanical Works Paper 2 WASSCE (SC), 2019

SECTION B

 

Question 12

 

(Use the sketch in Fig. 1 to answer question 12


Fig.1: Propeller Shaft

 

  1.   Name the parts labelled V, W, X, Y and Z.

  2.   State one function of the component in automobile transmission system.

  3.   State the function of the part labelled Z.

  4.   State three operational steps taken in checking the component for straightness.


Observation

 

 

Candidates’ performance in this question was not satisfactory.

Solution to the question


  1. Names of Labelled Parts
       V:     Spider/Trunion/Universal joint
      W:     Spline
       X:     Yoke
       Y:     Tubed shaft       
       Z:     Sliding Joint       

  2. Functions of Propeller Shaft

    - It connects the output shaft of the gearbox to the final drive.
    - It withstands the torsional stresses of the transmitting torque.
    - Continuous rises and falls of the rear axle is compensated for by the splines on the shaft.
    - It ensures that the pinion nose is forced upward when engine torque is applied to the pinion and is forced down when the brakes are applied.

  3. Function of Sliding Joint (the Part Labelled Z)

    It (Sliding Joint) varies the length of the propeller shaft in line with road condition and suspension system. 

  4. Operational Steps Taken in Checking Propeller Shaft for Straightness

               -  Placing a pair of V-block on a surface table
               -  Placing the propeller shaft on the V-block
               -  Moving a dial indicator or surface gauge along the length of the shaft
               -  Rotating the shaft through 90o
               -  Determining the straightness by the reading on the dial indicator or variation from the surface gauge