Steering device for vehicle
AssigneeToyota Jidosha Kabushiki Kaisha
InventorMasaharu Yamashita
Life of this patent
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Abstract
A vehicle steering device has an electric power abnormality detection portion that detects abnormality of the source power supply capability of an electric power source device, a vehicle speed detection portion that detects the vehicle speed, and a motor control portion that controls the driving of the electric motor on the basis of the steering torque detected by the steering torque detection portion. The motor control portion enhances the output restriction of the electric motor if the vehicle speed detected by the vehicle speed detection portion declines while the abnormality of the source power supply capability of the electric power source device is detected by the electric power abnormality detection portion.
Claims11
(canceled)
The vehicle steering device according to claim 11, wherein the output restriction portion stores relation-connecting information that indicates relation of an output upper limit value of the electric motor with the vehicle speed detected by the vehicle speed detection portion, and the relation-connecting information is set so that if the vehicle speed decreases, an output upper limit value of the electric motor decreases, and the motor control portion controls such that output of the electric motor does not exceed the output upper limit value that is found based on the relation-connecting information.
The vehicle steering control device according to claim 11, further comprising a voltage sensor that detects voltage of the electric power source device,
- wherein the electric power abnormality detection portion detects abnormality of the source power supply capability of the electric power source device by comparing the voltage detected by the voltage sensor with a pre-set power source fail criterion voltage.
The vehicle steering device according to claim 11, wherein the electric power source device includes a main electric power source that supplies source power to a plurality of electrical loads provided in the vehicle, including the electric motor, and a subsidiary electric power source that is connected in parallel with and between the main electric power source and the electric motor, and that stores electric power output by the main electric power source, and that assists in supplying source power to the electric motor by using the electric power stored, and
- wherein the electric power abnormality detection portion detects a state of being unable to supply source power from the main electric power source to the electric motor.
A method for controlling output of an electric motor that is supplied with source power from an electric power source device and generates assist force that assists in an steering operation of a steering wheel for a vehicle, the method comprising:
- detecting abnormality of source power supply capability of the electric power source device;
- detecting a vehicle speed;
- controlling the output of the electric motor so that output restriction of the electric motor is enhanced as the detected vehicle speed decreases while the abnormality of the source power supply capability of the electric power source device is detected.
A vehicle steering device comprising:
- a steering mechanism that steers a wheel upon steering operation of a steering wheel;
- an electric motor that is supplied with source power from an electric power source device and generates assist force that assists in the steering operation of the steering wheel;
- a steering torque detection portion that detects steering torque that a vehicle driver inputs to the steering wheel;
- an electric power abnormality detection portion that detects abnormality of source power supply capability of the electric power source device;
- a vehicle speed detection portion that detects vehicle speed;
- and
- a motor control portion that controls driving of the electric motor based on at least the steering torque detected by the steering torque detection portion, wherein the motor control portion includes an output restriction portion that enhances output restriction of the electric motor as the vehicle speed detected by the vehicle speed detection portion decreases while the abnormality of the source power supply capability of the electric power source device is detected by the electric power abnormality detection portion.
Dependencies are inferred from the claim text.