Electric power steering system i.e. servo steering mechanism, for passenger car, has gear housing including heat transfer portion, and roller bearing whose inner ring is directly or indirectly heated by transfer portion

摘要

The system (1) has a driving screw (4) driven by a traction drive (3) of an electric servo motor (2) on an axially undisplaceable nut (6) that is mounted on a cylindrical steering gear housing (5). A ball screw (8) of an axially displaceable component (7) i.e. rack, is engaged with a female thread (9) of the nut. A roller bearing (10) axially and/or radially bears the nut in the housing that includes a heat transfer portion (11). An inner ring (12) of the bearing is directly or indirectly heated by the transfer portion. A belt pulley (13) is made of high thermal conductivity material.