Driveshaft assembly

A vehicle driveline comprising:

• a first driveline component;
• a second driveline component;
• and
• a driveshaft coupling the first driveline component to the second driveline component to transmit drive torque therebetween, the driveshaft having a hollow shaft, a pair of caps, and a pair of universal joints, the hollow shaft having an annular wall member that defines an outer surface, an inner surface and a pair of opposite axial ends, at least one of the outer surface and the inner surface having a plurality of longitudinally extending splines and a plurality of longitudinally extending grooves that are disposed between the plurality of longitudinally extending splines, the pair of caps being fixedly coupled to the hollow shaft to at least substantially close the opposite axial ends, each of the universal joints being coupled to an associated one of the caps;
• wherein the longitudinally extending splines extend along the hollow shaft between the caps,
• wherein each of the plurality of longitudinally extending splines is disposed between a pair of longitudinally extending grooves, wherein each of the longitudinally extending splines has a convex crown that is defined by a first radius and wherein each of the longitudinally extending grooves has a root that is defined by a second radius.

A driveshaft comprising:

• a hollow shaft that is rotatable about an axis, the hollow shaft having an annular wall member that defines an outer surface, an inner surface and a pair of opposite ends, at least one of the outer surface and the inner surface including a plurality of longitudinally extending splines;
• a discrete vibration attenuating element received into the hollow shaft and engaged to the inner surface;
• a pair of caps fixedly coupled to the opposite ends of the hollow shaft to at least substantially close the opposite ends;
• and
• a universal joint coupled to one of the caps;
• wherein the splines extend the length of the hollow shaft, wherein each of the plurality of longitudinally extending splines is disposed between a pair of longitudinally extending grooves, wherein each of the longitudinally extending splines has a crown that is defined by a first radius and wherein each of the longitudinally extending grooves has a root that is defined by a second radius, wherein each root is tangent an associated one of the crowns, wherein the first radius is larger than the second radius, wherein a distribution ratio of the hollow shaft is defined by dividing the portion of a surface area of the at least one of the outer surface and the inner surface that conforms to the crowns by the surface area of the at least one of the outer surface and the inner surface and wherein the distribution ratio of the hollow shaft is greater than about 45%, wherein the plurality of longitudinally extending splines are uniformly spaced apart around the at least one of the outer surface and the inner surface, wherein each of the caps has a male spline connector portion that is received into the hollow shaft and which matingly engages the plurality of longitudinally extending splines, wherein the vibration attenuating element is located at a node of a bending mode, and wherein a lateral cross-section of the hollow shaft is uniform over the entire length of the hollow shaft.