This page was last edited on 9 March 2017, at 23:59. Cracks and splits in the boot will allow contaminants in, which would cause the joint to wear quickly as grease how to link to a pdf in constant contact out.
This way the friction parts don’t get proper lubrication and get damaged due to minor particles that get in, while water causes metal components to rust and corrode. Cracks and tears in the areas closer to the axle are usually caused by external factors, such as packed snow, stones or uneven rocky off-road paths. 17th century, who proposed the first constant velocity joint, consisting of two Cardan joints offset by 90 degrees, so as to cancel out the velocity variations. Many different types of constant-velocity joints have been invented since then. These are not CV joints as, except for specific configurations, they result in a variation of the angular velocity. They are simple to make and can be tremendously strong and are still used to provide a flexible coupling in some propshafts, where there is not very much movement.
However, they become “notchy” and difficult to turn when operated at extreme angles. They allowed a smooth transfer of power despite the wide range of angles through which they were bent. Each yoke jaw engages a circular groove formed on the intermediate members. Both intermediate members are coupled together in turn by a swivel tongue and grooved joint. When the input and output shafts are inclined at some working angle to each other, the driving intermediate member accelerates and decelerates during each revolution.
Since the central tongue and groove joint are a quarter of a revolution out of phase with the yoke jaws, the corresponding speed fluctuation of the driven intermediate and output jaw members exactly counteracts and neutralizes the speed variation of the input half member. Thus the output speed change is identical to that of the input drive, providing constant velocity rotation. 6 grooves in it and a similar enveloping outer shell. Each groove guides one ball. The input shaft fits in the centre of a large, steel, star-shaped “gear” that nests inside a circular cage. The cage is spherical but with ends open, and it typically has six openings around the perimeter.
This cage and gear fit into a grooved cup that has a splined and threaded shaft attached to it. Six large steel balls sit inside the cup grooves and fit into the cage openings, nestled in the grooves of the star gear. The output shaft on the cup then runs through the wheel bearing and is secured by the axle nut. At the “outboard” end of the driveshaft a slightly different unit is used.