US 11,697,455 B2
Turning system
Ruriko Sakaguchi, Toyota (JP)
Assigned to TOYOTA JIDOSHA KABUSHIKI KAISHA, Toyota (JP)
Filed by TOYOTA JIDOSHA KABUSHIKI KAISHA, Toyota (JP)
Filed on Oct. 4, 2019, as Appl. No. 16/592,889.
Claims priority of application No. 2018-227291 (JP), filed on Dec. 4, 2018.
Prior Publication US 2020/0172160 A1, Jun. 4, 2020
Int. Cl. B62D 6/00 (2006.01); B62D 3/12 (2006.01); B62D 5/06 (2006.01); B62D 5/083 (2006.01); B62D 1/04 (2006.01); B62D 5/12 (2006.01); B62D 5/04 (2006.01); B62D 5/09 (2006.01)
CPC B62D 6/005 (2013.01) [B62D 1/04 (2013.01); B62D 3/126 (2013.01); B62D 5/046 (2013.01); B62D 5/0424 (2013.01); B62D 5/063 (2013.01); B62D 5/083 (2013.01); B62D 5/091 (2013.01); B62D 5/12 (2013.01)] 5 Claims
OG exemplary drawing
 
1. A turning system configured to move a turning shaft to turn a left wheel and a right wheel of a vehicle, the turning shaft being configured to couple the left wheel and the right wheel to each other, a torsion bar being engaged with the turning shaft via a steering gear box, the turning system comprising:
a turning mechanism comprising (i) an electric turning mechanism comprising an electric motor configured to rotate a portion of the torsion bar which is located upstream of the steering gear box and (ii) a hydraulic turning mechanism configured to apply a moving force to the turning shaft in an axial direction, the moving force being produced by a hydraulic pressure; and
an electric-motor controller configured to control the electric motor based on a frictional force in the turning mechanism and a road-surface reaction force that acts between (a) a tire on the left wheel and a tire on the right wheel and (b) a road surface,
wherein the electric-motor controller comprises a twist-angle obtainer configured to obtain an angle of twist of the torsion bar based on the frictional force in the turning mechanism and the road-surface reaction force, and the electric-motor controller is configured to control the electric motor based on the angle of twist of the torsion bar which is obtained by the twist-angle obtainer,
wherein the steering gear box comprises a rack-and-pinion mechanism,
wherein the torsion bar is coupled rotatably and integrally with a pinion gear,
wherein the pinion gear is engaged in the steering gear box with a tooth portion of a rack bar that is the turning shaft, and
wherein the electric-motor controller comprises:
a target-pinion-rotation-angle determiner configured to determine a target pinion rotation angle based on a state of the vehicle, the target pinion rotation angle being a target rotation angle of the pinion gear;
a current controller configured to control a current to be supplied to the electric motor, such that an actual rotation angle of the electric motor is brought closer to a target motor rotation angle that is a target rotation angle of the electric motor; and
a target-motor-rotation-angle determiner configured to determine the target motor rotation angle to a value obtained by adding the angle of twist of the torsion bar which is obtained by the twist-angle obtainer, to the target pinion rotation angle determined by the target-pinion-rotation-angle determiner.