steering gear mechanism ppt

tarique siddiqui......The ICFAI University

1. Topic :- Steering G ear Mechanism by Tarique Siddiqui 131MC00216 Submitted to :- Mr. P. Jagan Mohan

2. INRODUCTION The steering gear mechanism is used for changing the direction of two or more of the wheel axles with reference to the chassis. Usually, Back wheel axle is fixed in direction with reference to the chassis and the steering is done by means of the front wheels. When the vehicle takes turn, the front wheels along with the respective axles turn about corresponding pivoted points. Also, the back wheels remain straight and do not turn. Therefore, steering is done by means of the front wheels.

3. In order to avoid skidding(slipping of the wheels of sideways),the two front wheels must turn about the same instantaneous centre which lies on the axis of the back wheels . if this does not happen, the skidding on the front or back wheels will definitely take place, which will in turn produce more wear and tear on the tyres.

4. Basic geometry The basic aim of steering is to ensure that the wheels are pointing in the desired directions. This is typically achieved by a series of linkages, rods, pivots and gears.  

5. Steering principle A C E F B a b I f q

6. PRINCIPLE OF WORKING Ackermann steering mechanism Ackermann steering geometry is a geometric arrangement of linkages in the  steering  of a  car  or other vehicle  designed to solve the problem of wheels on the inside and outside of a turn needing to trace out circles  of different  radius .

7. When the vehicle moves along straight path, the longer links AB and CD are parallel and the shorter links BC and AD are equally inclined to the longitudinal axis of the vehicle. When the vehicle moves left, the position of the gear is shown by dotted lines in fig.

8. Davis Steering This is an exact steering gear mechanism . This mechanism fulfils the above steering condition. But due to presence of more sliding members, the wear will be increased and this eliminates the accuracy .

9. ( i ) (ii) (iii)

10. Difference between Ackermann and D a vis mechanism The whole mechanism is on back of the front wheels , whereas in Davis ,it is in front of the wheels. It consists of turning pairs, whereas in Davis, it consists of sliding pairs.

11. Thank You