Hitachi Automotive Systems Steering, Ltd.

Hitachi Automotive Systems, Ltd.

Atsushi Yoshitake

Kohtaro Shiino

Takahiro Mori

Takumi Hisazumi

Yusuke Fukuda

Kazuya Yamano

Yoshitaka Sugiyama

Tatsuro Suzuki

Masaki Kodato

In a power steering system, a torque sensor obtains first and second rotation angles, and a steering angle sensor obtains third and fourth rotation angles. A controller includes a first absolute rotation angle calculation section, a second absolute rotation angle calculation section, and an abnormality detection section. The first absolute rotation angle calculation section calculates a first absolute rotation angle as a first estimate of an absolute rotation angle of a steering wheel based on the first and third rotation angles. The second absolute rotation angle calculation section calculates a second absolute rotation angle as a second estimate of the absolute rotation angle of the steering wheel based on the third and fourth rotation angles. The abnormality detection section detects an abnormality by comparison between the first absolute rotation angle and the second absolute rotation angle.

Power steering apparatus, and controller for power steering apparatus

In a power steering system, at least one of phase open relays in which a contact weld (an abnormality) occurs is detected. That is to say, the power steering system comprises an abnormality monitor section () configured to output vector control command signals to supply only a d-axis current in a positive side direction toward the motor, with all of phase open relays () in an interruption state, and to determine an abnormality in at least one of the phase open relays in a case where a current value is detected by a current detection circuit which detects a current flowing into an inverter. In a case of three phase open relays installed between respective three phases of motor windings, a potential difference is detected at a neutral position of a star connection to determine the abnormality of at least two of the phase open relays.

Power steering system

In a power steering system and a control apparatus for the power steering system, an abnormality detection process section () installed in a second ECU, the second ECU, the second ECU having a multi-core microcomputer in which a plurality of processor cores are mounted within a single processor package, to detect an abnormality of a first angle calculation process section of a first ECU, the first ECU having a single core microcomputer in which a single processor core is mounted within another single processor package and the first angle calculation process section a first angle calculation process section () installed in the first ECU to calculate rotation angles of the input axle and output axle on a basis of sinusoidal wave signals and cosine wave signals derived from a steering angle sensor and a torque sensor.

Power steering system and control apparatus for power steering system

In an electrically driven power steering system having a blushless three phase motor, an abnormality of a control unit is detected on a basis of a direct current bus bar current of an inverter detected by a current sensor and an estimated primary current. The estimated primary current is calculated from, for example, the following equation, namely, Iu&#xd7;Du+Iv&#xd7;Dv+Iw&#xd7;Dw)/100%, wherein Iu denotes a current of a U phase of the motor, Du denotes a PWM duty signal of the U phase, Iv denotes a current of a V phase of the motor, Dv denotes the PWM duty signal of the V phase of the motor, Iw denotes a current of a W phase of the motor, and Dw denotes the PWM duty signal of the W phase.

Electrically driven power steering system

Electric power steering system has steering mechanism; input and output shaft side rotation angle sensors detecting rotation angles of input and output shafts; operation circuit calculating command current for an electric motor; rotation direction judging circuit judging whether rotation directions of the input and output shafts are identical; advanced-phase judging circuit judging which phase of input and output shaft side rotation angle signals (S, S) is advanced; normal/reverse input judging circuit judging that (i) when both rotation directions are identical and Sis advanced, input is normal input and (ii) when both rotation directions are identical and Sis advanced, input is reverse input; and command current correcting circuit. The command current correcting circuit corrects the command current so that when the normal input is judged, torque in the same direction as input shaft rotation direction generated by the electric motor is greater than a case of reverse input judgment.

Electric power steering system and controller of the electric power steering system

A power steering apparatus includes a worm wheel mounted on the steering shaft, a worm shaft engaged with the worm wheel, a gear housing having a wheel accommodating portion to accommodate the worm wheel and a shaft accommodating portion to accommodate the worm shaft, a bearing mounted on the worm shaft to rotatably support the worm shaft, a holder disposed in the shaft accommodating portion and having a bearing retaining portion to retain the bearing and a resilient element disposed in the shaft accommodating portion and having a resilient body portion formed with a curvature. The resilient body portion is so structured as to become deformed in such a manner as to increase or decrease in diameter when the bearing shifts in a direction that moves the worm shaft away from the worm wheel and bias the bearing in a direction that urges the worm wheel toward the worm wheel.

Growing community of inventors

Ebina, Japan

Atsushi Yoshitake