1. Field of the Invention
The present invention relates to a sliding homokinetic transmission joint intended for motor vehicles.
2. Description of the Prior Art
More particularly, the invention concerns joints of the type comprising a tripod locked in rotation with a driving shaft and provided with three radial arms capable of sliding axially on flat rolling tracks provided inside a drum locked in rotation with a driven shaft, rows of needle rollers arranged between the arms of the tripod and the rolling tracks, and also cages for holding the rows of needle rollers. The cages are guided laterally by parallel shoulders defining the upper and lower edges of the rolling tracks, such that the cages remain exactly aligned parallel to the general axis of the rolling track, itself parallel to the axis of the drum. Consequently, the needles, which are held by the cage so that they are perpendicular to the longitudinal axis of the latter, always roll precisely in their natural direction, i.e. without sliding and without giving rise to lateral frictional forces. Such a joint is described in French Pat. No. 2,506,872.
So that there is sufficient angular clearance for the driving shaft, the internal guiding shoulder close to the edge of the drum must be eliminated, for which purpose a chamfer of large dimensions is machined in the latter. Consequently, at the end of the extension of the driving shaft, the cage is not guided properly and undesirable friction and frequent binding occur.