Patent ID: 11964713
Assignee: NSK LTD.
Field: Transport (Mechanical engineering)
Classification: CPC B | IPC B

Claim 0:
1. A vehicle steering device comprising:
a reaction force device configured to apply steering reaction force to a wheel;
a drive device configured to turn tires in accordance with steering of the wheel; and
a control unit configured to control the reaction force device and the drive device, wherein
the control unit includes
a turning ratio map unit configured to set a turning ratio gain in accordance with a vehicle speed of a vehicle, and
a target turning angle generation unit configured to generate a target turning angle by multiplying a steering angle of the wheel by the turning ratio gain,

the turning ratio gain at backward traveling of the vehicle is equal to or larger than the turning ratio gain at forward traveling of the vehicle,
when a first region is defined to be a region in which the magnitude of the vehicle speed at forward traveling of the vehicle is equal to or larger than zero and smaller than a first vehicle speed, a first gain being defined to be the turning ratio gain in the first region,
a second region is defined to be a region in which the magnitude of the vehicle speed at forward traveling of the vehicle is equal to or larger than the first vehicle speed and smaller than a second vehicle speed higher than the first vehicle speed, a second gain being defined to be the turning ratio gain in the second region,
a third region is defined to be a region in which the magnitude of the vehicle speed at forward traveling of the vehicle is equal to or larger than the second vehicle speed, a third gain being defined to be the turning ratio gain in the third region,
a fourth region is defined to be a region in which the magnitude of the vehicle speed at backward traveling of the vehicle is larger than zero and smaller than a third vehicle speed, a fourth gain being defined to be the turning ratio gain in the fourth region,
a fifth region is defined to be a region in which the magnitude of the vehicle speed at backward traveling of the vehicle is equal to or larger than the third vehicle speed and smaller than a fourth vehicle speed higher than the third vehicle speed, a fifth gain being defined to be the turning ratio gain in the fifth region, and
a sixth region is defined to be a region in which the magnitude of the vehicle speed at backward traveling of the vehicle is equal to or larger than the fourth vehicle speed, a sixth gain being defined to be the turning ratio gain in the sixth region,
the fourth gain is a constant value larger than the first gain, the second gain, the third gain, the fifth gain, and the sixth gain.