US 11,685,426 B2
Apparatus for use in turning steerable vehicle wheels
Mark Andrew Cartwright, West Lafayette, IN (US); David Lee Welker, Lafayette, IN (US); and Hendrik Wellen, Duesseldorf (DE)
Assigned to ZF FRIEDRICHSHAFEN AG, Friedrichshafen (DE)
Filed by ZF FRIEDRICHSHAFEN AG, Friedrichshafen (DE)
Filed on Nov. 30, 2020, as Appl. No. 17/106,319.
Prior Publication US 2022/0169305 A1, Jun. 2, 2022
Int. Cl. B62D 5/04 (2006.01)
CPC B62D 5/0448 (2013.01) [B62D 5/0409 (2013.01)] 12 Claims
OG exemplary drawing
 
1. An apparatus for use in turning steerable vehicle wheels, comprising:
a rotatable output shaft that is selectively rotatable to effect turning movement of at least one vehicle wheel;
a housing supporting the output shaft for rotation relative thereto about a shaft axis;
a first rotational input assembly for transmitting a steering command from a steering control member to the output shaft; and
a power transmitting mechanism located within the housing and being configured to transmit a rotational force from the input assembly to the output shaft, the power transmitting mechanism including
a plurality of sector gears, each sector gear being operatively connected to the output shaft at a lateral spacing from each other, and each said sector gear including sector gear teeth,
a ball screw having longitudinally separated first and second ball screw ends, and
a ball nut having a plurality of rack gears, each rack gear being operatively connected to the ball nut at a lateral spacing from each other, each said rack gear including rack gear teeth configured for selective engagement with corresponding sector gear teeth, and the ball nut being operatively engaged with the ball screw;
wherein the rotational force from the input assembly turns the ball screw, and the ball nut reciprocates within the housing responsive to rotation of the ball screw to move each of the plurality of rack gears in a longitudinal direction, such that longitudinal motion of the rack gear teeth responsively drives the sector gear teeth and thereby transmits the steering command to the output shaft through toothed engagement between each said rack gear and the corresponding sector gear.