Nsk Corporation

Tamotsu Oumi

Mikihiko Tsunoda

Seiichi Kobayashi

Takahiro Tsubaki

Shigeru Endo

Toshihiro Fukuda

Hideaki Kawada

Takaaki Sekine

Atsushi Horikoshi

Shigeo Shinohara

Takeshi Senba

Yasuhiro Shimizu

Yasuhide Nomura

Mitsunori Okubo

Keiji Kashimoto

Atsushi Ooshima

Tetsuya Kodama

Naoki Hyoudou

Mitsuo Shimoda

An electric power steering apparatus that driving-controls a motor via inverters based on a current command value, and applies an assist force by the motor to a steering system, includes multi-system driving systems with the inverters for respective system-windings of the motor which is a multi-system motor, wherein respective multi-system current command value characteristics against a steering torque are applied so as to be disproportionate for left and right steering, to the respective multi-system driving systems, and an assist-control is performed in response to the individual current command value characteristics.

Electric power steering apparatus

[Problem] An object of the present invention is to provide an electric power steering apparatus that suppresses a handle vibration (noisy sound) being caused by a handle inertia and a spring nature of a torsion bar and improves a steering feeling, without changing of the gain of the PI control. [Means for solving the problem] The present invention is an electric power steering apparatus that assist-controls a steering by driving a motor with a current command value calculated based on at least a steering torque, comprising a vibration-damping compensating section that calculates a vibration-damping compensation command value for suppressing a vibration of a handle based on a motor velocity of the motor, wherein the current command value is corrected by the vibration-damping compensation command value.

In a torque sensor of an electric power steering device, a natural and comfortable feeling to a driver (driver) is achieved by increasing the physical quantity of the torque sensor around the center of the steering wheel (neutral position). A torsion bar () for use in the torque sensor includes a core torsion bar (A) and a tubular torsion bar (B). The tubular torsion bar (B) includes a pair of torsion tubular bar parts (Ba,Bb), accommodates the core torsion bar (A) in its inside, secures both ends of the core torsion bar (A) in its inside, and the pair of tubular torsion parts (Ba,Bb) mesh and couple each other by meshing teeth, when the core torsion bar (A) twists a predefined rotational angle, so that a single torsion bar is configured. The elasticity of the tubular torsion bar (B) is larger than that of the core torsion bar (A).

Torque sensor and electric power steering device

There is provided an electric power steering device capable of detecting steering torque with high accuracy without use of a torque sensor, and capable of performing appropriate steering assistance control. An alternative torque correction value (Tc) is operated by comparing alternative torque (T) operated based on an angle signal at normal time of the torque sensor () with a torque detection value (Ti) detected by the torque sensor (), and is then stored. Then, at normal time of the torque sensor (), the steering assistance control is performed based on the torque detection value (Ti) detected by the torque sensor (), whereas when an abnormality happens in the torque sensor (), the steering assistance control is performed based on corrected alternative torque (T) obtained by correcting the alternative torque (T) by the alternative torque correction value (Tc).

There is provided an electric power steering apparatus capable of dealing with abnormality when the abnormality happens in the torque, without being affected by an abnormal torque signal and without giving the driver a feeling of strangeness. Abnormality is detected with a double detection configuration including a main ECU clip and a sub ECU interlock. Then when abnormality is detected in steering torque detected by a torque sensor, the input of a main ECU clip is switched from the steering torque detected by the torque sensor to a torque alternative value, and the input value of the sub ECU interlock is switched from a steering assist command value subjected to limiting at the main ECU clip to zero.

A motor control apparatus includes a steering column having inserted therein a steering shaft to which steering torque is transmitted, a reduction gear box coupled to the steering shaft, and an electric motor that transmits a steering assisting force to the steering shaft via a reduction mechanism in the reduction gear box. The electric motor and its control unit including a control board mounted with a control circuit, are provided side by side in the reduction gear box. A connection terminal of the electric motor is electrically connected to the control unit directly. This minimizes a connection distance between the control unit and the electric motor.

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Maebashi, Japan

Tamotsu Oumi