The present invention relates to an electromechanical
power steering system for a motor vehicle, comprising a
servomotor (1) and a
ball screw drive (2), wherein the
ball screw drive (2) has a belt
pulley (3), a ball nut (4), and a threaded spindle (5), wherein the belt
pulley (3) is arranged concentrically to the ball nut (4) and surrounds it, wherein the ball nut (4) engages with the threaded spindle (5), wherein the belt
pulley (3) can be driven by the
servomotor (1) via a drive belt (6), wherein the belt pulley (3) has, on a first half of its inner circumference, two radially inwardly extending projections (7, 8), which are positively connected to the ball nut (4) in the circumferential direction, wherein the belt pulley (3) has, on a second half of its inner circumference, a third projection (9), which extends radially inwardly and via which the belt pulley (3) is supported on the outer circumference (10) of the ball nut (4).In order to further develop such an electromechanical
power steering system in such a way that, on the one hand, there is great design freedom with regard to the design of the components of the
ball screw drive, and, on the other hand, that the pushing-through force, i.e. the force required to move the rack, has a force-displacement curve which has little
ripple without large force peaks, with vibrations and
noise development being as low as possible, it is proposed that the belt pulley (3) has compensating material (12a, 12b) on its inner circumference (11) on both sides of the third projection (9), by means of which compensating material any imbalance of the
ball screw drive (2) is compensated.