Constant Velocity Joints (CV Joints) Information
Constant velocity (CV) joints are mechanical power transmission components that provide rotational power at various angles. They provide the same output velocity in relation to the input velocity, independent of the angle they are operated at. This contrasts with most other joints, which may provide a different output velocity at sharper angles even with the same input velocity.
A CV joint may operate efficiently up to 80° deviation from a straight line. By operating in pairs, larger angles are possible. The effective life of a CV joint will generally be shortened as joint angle increases. CV joints are effective for high velocity power transmission where operating angles are acute. CV joints tend to be heavier and more expensive than universal joints and tend to fail more quickly.
CV joints often connect two intersecting, rotating shafts that make an angle with one another, especially when this angle regularly varies in service. A common example is found in front wheel-drive cars at the connection of a half-axle with a front wheel, where the CV joint ensures even torque transmission when the wheel moves due to steering. Another example is found in rear wheel-drive cars with independent rear suspensions where the rear axle half-shafts connect with the rear wheels.
A CV joint is an assembly of bearings and cages that allows for axle rotation and power transmission at a number of different angles. CV joints consist of a cage, balls, and inner raceway encased in a housing covered by a rubber boot, all of which is filled with lubricating grease. The grease is necessary to reduce the friction of all the spinning parts of the CV joint. Cracks in the boot will allow in contaminants, which can cause heat due to friction and cause the joint to wear quickly.
The following video, though somewhat outdated, concisely illustrates the function of CV joints.
CV joints on Buick vehicles
Video credit: Buick/GM (posted by RivLanta via YouTube)