Abstract: An axially collapsible driveshaft includes a first driveshaft tube section, a connecting member having a first end portion that is secured to the first driveshaft tube section, and a second driveshaft tube that is secured to a second end portion of the connecting member. During normal operation of the drive train assembly, torque is transmitted through the driveshaft by means of the securement between the first driveshaft tube section, the connecting member, and the second driveshaft tube section. However, if a relatively large axial force is applied to the end portions of the driveshaft, either or both of the end portions of the connecting member are designed to fracture, allowing relative axial movement to occur between the first driveshaft tube section and the second driveshaft tube section. An annular recess may be formed in the connecting member adjacent to either or both of the end portions that are secured to the driveshaft tube sections.

Abstract: A driveshaft assembly includes a cylindrically shaped driveshaft tube and a tube yoke. The tube yoke is attached to the driveshaft tube and transfers torque between the driveshaft tube and a universal joint. The tube yoke has a first end having a tube seat for connecting the driveshaft tube to the tube yoke and a second end having lugs for connecting the tube yoke to the universal joint. The tube seat has an outer surface which is fixed to the driveshaft tube to prevent relative movement between the driveshaft tube and the tube yoke. A diamond-shaped relief formed in an end surface of the tube seat has two pairs of opposed points, with each point positioned 90 degrees from another point. Flats are formed between each adjacent points. The diamond-shaped relief is oriented to provide tube seat walls which are thickest at the locations which receive the greatest stress during rotation of the driveshaft assembly.