There are two stub Axle made of steel forgings, Fitted to front axle and mounted to the axle beam by pivot pins so that they can swivel as required for steering, Each axle is made complete with an arm the stub axle arm are connected to each other by a track rod in addition one of them has a steering arm for connection to the pull and push rod. Thus any movement of the pull & push rod Swivel the stub axle. On swivel pin these swivel pins are also known as King Pin or pivot pin. These pins are generally made of good quality steel case hardened and used to stub axle to the axle beam. They are locked in position by a cotter pins. The steering knuckles are mounted on each end of the axle “I” beam and knuckle, which permits easy steering under the load.
TYPES OF STUB AXLE
There are two types of stub axles Elliot Type and Reverse Elliot Type.
(a) Elliot Type. In this design swivel pin is fixed in the stub axle, forging the ends of swivel pin can turn freely in the bushes fixed in the bushes fixed in the axle beam fork.
(b) Reverse Elliot. This design is one of the most commonly used and has the swivel pin fixed in the Ends of the axle beam and locked by a cotter pin, so that the forked stub axle can turn on the swivel pin ends.
Live Axles are classified as fully floating, semi floating and three quarter floating according to the method by which wheels are mounted on. Or are connected to the axle casing and the axle shaft .Axle bearings may be ball, roller or taper roller bearings and are lubricated by grease or oil.
(a) Semi Floating Type. In this type each wheel hub is rigidly secured by spins or keys to the end of the axle shaft and shaft support the axle casing through a roller or ball bearing. A special nut screwed to the end of axle casing retains the balls or roller bearings and the axle in position.
(b) Fully Floating Type. An Axle is said to be Fully Floating when the axle shaft transmit drive from the differential gear and performs no other function. wheel hub are entirely supported on the ends of the axle casing by two ball or roller bearings .this type of axle suitable for carrying heavy loads because the wheels support the axle casing direct and are in no way dependent up on the axle casing direct .The axle shaft are splined at the inner end and engages with the sun wheel while the outer end carries a flange which is bolted to the wheel hub.
(c) Three Quarter Floating . This is compromise between fully floating and semi floating type. The axle shafts are rigidly secured to the wheel hubs but the ball &roller bearings are fitted directly between the hub and casing to the wheel and is not taken by the axle shafts.