Subject: Automobile Engineering

Topic: Brakes, Steering & Front Axles

Difficulty: Medium

It is an improved version of the worm & nut steering geat. It consists of a worm at the end of steering rod. A nut is mounted on worm with two set of balls in the grooves of the worm, in between the nut & worm. (Fig 14.1) The function of ball is to reduce the friction between the worm & nut The nut has a number of teeth on the outside which mesh with teeth on worm wheel sector. The drop arm is mounted on wheel sector, which transfer the motion to steering arms through linkages. When the steering wheel turn,the balls in the worm groove rolls, causes to nut slides on the worm. This linear motion of nut cause the wheel sector turn at an angle & actuate the linkage rod through droparm,

resulting in the desired steering of wheels. The end play of the worm can be adjusted with the help of adjuster nut provided. A screw is also provided by means of which the drop arm & hence the wheel sector can be positioned along its axis.