Ball joint

This article is about automobile joints. For the anatomical structure, see Ball-and-socket joint.
A typical ball joint with cutaway view (right)
An inner tie rod end cut open to expose the ball joint.

In an automobile, ball joints are spherical bearings that connect the control arms to the steering knuckles, and are used on virtually every automobile made.[1] They bionically resemble the ball-and-socket joints found in most tetrapod animals.[2]

A ball joint consists of a bearing stud and socket enclosed in a casing; all these parts are made of steel. The bearing stud is tapered and threaded, and fits into a tapered hole in the steering knuckle. A protective encasing prevents dirt from getting into the joint assembly. Usually, this is a rubber-like boot that allows movement and expansion of lubricant. Motion-control ball joints tend to be retained with an internal spring, which helps to prevent vibration problems in the linkage.

The "offset" ball joint provides means of movement in systems where thermal expansion and contraction, shock, seismic motion, and torsional motions, and forces are present.[3]

  1. ^ Cite error: The named reference mobile was invoked but never defined (see the help page).
  2. ^ "Your Car's Ball Joints - The Pivotal Part of the System". California Dept. of Consumer Affairs, Bureau of Automotive Repair. 2010. Archived from the original on September 1, 2012. Retrieved October 10, 2012.
  3. ^ "Ball Joints-Dannenbaum LLC". Dannenbaum LLC.