Steering Joints
When it comes to driving a car, boat, motorcycles, ships, airplanes or basically any transportation medium it requires steering, in other words controlling. Either to turn left or right or simple burning rubber while making a “doughnut”. The steering is where all the control is, you can basically make the vehicle go any direction you want. The term “steering” applies to a set of mechanical components consisting of several linkages. This applies to almost any type of vehicle; railroad transportation is an exception here, as in that case the steering is achieved via the combination of railroad switches and the rail tracks.
There are several kinds of steering systems used in modern vehicles. There is the “tiller” or “rear steering” usually applied in boats, ships and small planes. The till is connected to rudder stock or rudder post which is pulled or pushed by personnel depending on the direction of course. This may also be controlled remotely via tiller lines. “Tracked” vehicles such as tanks, bull dozers etc. use differential steering – in this case the tracks are made to move at different speeds or even directions in order to achieve change in course.
The most popular type of steering system, used in cars and general automotive, usually consists of a hand-operated steering wheel placed in front of the motorist, which is connected to the front wheels via the steering column. This steering column usually consists of one or more (depending on type of vehicle) steering joints such as the U-joints or Universal joints, CV joints or constant-velocity joints and ball joints. The steering joints, also found in collapsible steering column designs, allow the steering column to be bent or deviated from a straight line of path.
The U-joint, alternatively known as the Hooke’s joint, Hardy-Spicer Joint or Cardan joint, was one of the first steering joints used in steering columns of cars. It consists of a cross shaft which connects a pair of hinges usually located close and at a right angle to one another. This was later advanced to a “Double Cardan Shaft” in order to slightly overcome the jerky rotation experienced in the previously used U-joints. This configuration makes use of two U-joints connected via an intermediate shaft.
The CV joint or Constant-Velocity joint is generally used in front wheel drive cars. They usually consist of spherical internal component with grooves in it which has an external covering of the same shape, also with grooves in it. Bearing balls are placed in the grooves in order to keep a distance between the inner and outer components. During rotation, the grooves guide the bearing balls and a smooth constant rotational motion is achieved.
There are several kinds of CV joints; there is the Rzeppa Joint which uses the mechanism described in the immediate previous paragraph. The Rzeppa joints allow rotation while bending at astounding angles of 45 to 48 degrees; some joints can reach up to as much as 52 degrees. The Tripod Joints which consists of a three point yolk connected to the shaft which has roller bearings on each end shaped like a barrel. Then there is the Double Cardan Joint which is similar to the Double Cardan shaft but the shaft is reduced in length than that of the cardan shaft. And finally there is the Thompson Coupling, it is a constant velocity U-joint but allows axial loading while maintaining constant velocity at different shaft angles. Plus, it also provides reduced vibration and friction.
Talking about steering joints we simply cannot forget the ball joints. The ball joint is basically a steel spherical bearing that connects the steering knuckles with the control arms. It is one of the most important components of a steering system and plays a vital role ensuring safe functionality of the suspension and the steering. It consists of a protective cover in order to prevent dirt from entering the joint assembly. Ball joints with motion control tend to have a spring inside the socked in order to retain the ball in place; this also helps reduce the vibration problems usually encountered in the linkage.