Editing Constant-velocity joint (section)

=== Double Cardan Joint ===
[[Image:Double Cardan Joint (animated).gif|thumb|right|Double Cardan joint]]
Double Cardan Joints are similar to Hooke's use of two universal joints except that the length of the intermediate shaft is shortened leaving only the yokes; this effectively allows the two Hooke's joints to be mounted back to back. DCJs are typically used in steering columns, as they eliminate the need to correctly phase the universal joints at the ends of the intermediate shaft (IS), which eases packaging of the IS around the other components in the engine bay of the car. They are also used to replace Rzeppa style constant-velocity joints in applications where high articulation angles, or impulsive torque loads are common, such as the driveshafts and halfshafts of rugged four-wheel drive vehicles. 

To be truly constant-velocity, Double Cardan joints require a centering element that will maintain equal angles between the driven and driving shafts.<ref name="US patent 1979768">{{cite patent
 | country = US
 | number = 1979768
 | status = patent
 | title = Double Universal Joint
 | pubdate =
 | gdate = 1934-11-06
 | fdate = 1933-07-24
 | pridate =
 | inventor = Pearce, John W.B.
}}</ref><ref>[http://www.tpub.com/content/construction/14273/css/14273_181.htm Rzeppa Constant Velocity (CV) Joint<!-- Bot generated title -->] {{webarchive|url=https://web.archive.org/web/20090205182059/http://www.tpub.com/content/construction/14273/css/14273_181.htm |date=2009-02-05 }}</ref> This centering device requires additional torque to accelerate the internals of the joint and does generate some additional vibration at higher speeds.<ref name="US patent 2947158">{{cite patent
 | country = US
 | number = 2947158
 | status = patent
 | title = Universal Joint Centering Device
 | pubdate =
 | gdate = 1960-08-02
 | fdate = 1959-08-21
 | pridate =
 | inventor = King, Kenneth K.
 | assign1 = General Motors Corporation
}}. The usual centring arrangement is a ball and socket type of construction... . In order to provide the constant velocity feature for the <nowiki>[</nowiki>double cardan<nowiki>]</nowiki> joint, it is essential that the centre of angulation of each spider and bearing assembly, and each yoke, be maintained about the same point during the life of the joint.</ref>