A roller element (10) has a central body (1) and a roller unit (2). The
roller unit (2) is mounted so as to circulate on a non-circular race (21)
about the central body (1) and so as to be mobile with respect to the
central body (1) by the rolling movement of the rollers (3) of the roller
unit (2) on the central body (1). The rollers (3) are provided on the
exterior of the roller unit (2) for rolling off on a rigid counter body
(5). The roller element (10) is provided with a drive means (6) which
engages with the roller unit (2) and drives the same in relation to the
central body (1). The roller unit (2) is directly driven by engagement of
the drive (6) between the rollers (3) and is pulled or pushed on the race
(21) about the central body (1).