Joint of transmission
This article is one outline to supplement, you can share your knowledge in modifying.
- For the homonymous articles, to see .
One joint of transmission is a mechanical system composed of several moving parts the ones compared to the others, which allows the mutual drive of two revolving parts whose axes of rotation occupy of the variable relative positions during operation. In other terms it is a connection which makes it possible to transmit the rotation of an axis to another mobile axis compared to the first.
In the most frequent case, the trees which one wishes to connect are convergent and form between them a variable angle. In other cases, the trees are not aligned perfectly, but they remain parallel. Lastly, it is possible that the trees are neither convergent, nor parallel.
Such mechanisms are necessary, for example, to involve the driving wheels of a vehicle. occupies an almost fixed position compared to , it is assembled on anti-vibration elastic supports, while the movements of the suspension cause important displacements of the driving wheels. These last are in more directors on with traction.
Cardan joint
Cardan joint, whose invention is allotted probably wrongly to the mathematician Jerome Cardan joint, is undoubtedly the mechanism of the most known joint of transmission of name, but there are several tens of other systems - joints of Oldham, of Myard, Rzeppa, tripods... - used on the vehicles and more generally in. In much of case, it is very wrongly that one indicates under the name of "Cardan joints" the joints of transmission which equip the cars.
If the driving shaft turns of a whole number of turns, the driven shaft does as much of it. Speeds averages of the two trees are equal but it is not inevitably the case for speeds instantaneous. A joint of transmission is known as homokinetic if, at any moment, speeds of the two trees are equal. The simple Cardan joint is homokinetic only if the trees are aligned, the irregularities introduced into rotation being all the more important as the two trees move away more from this particular position.
