A longitudinal plunging unit (11) for torque transmitting purposes in a
shaft assembly, comprising an outer profiled sleeve (21) having
circumferentially distributed, inner, longitudinally extending first ball
grooves (22) to be connected to a first attachment part, a profiled
journal (31) positioned inside the outer profiled sleeve (21) and having
circumferentially distributed, outer, longitudinally extending second ball
grooves (32) to be connected to a second attachment part, groups of balls
(41) arranged in pairs of first and second ball grooves (22, 32), and a
sleeve-shaped ball cage (42) which is positioned in the annular space
between the profiled sleeve (21) and the profiled journal (31) and which
fixes the groups of balls (41) in their respective positions relative to
one another. The profiled sleeve (21) comprises a material with a
substantially uniform wall thickness with a maximum deviation in wall
thickness of .+-.15% and, in the region adjoining the first ball grooves
(22), towards the first attachment part, changes integrally into a first
cylindrical projection (23) and, in the region adjoining the first ball
grooves (22), towards the second attachment part, changes integrally into
a second cylindrical projection (25).
