Koyo Seiko Company, Ltd.

Hideki Jonokuchi

Hirohide Inayama

Atsushi Ishihara

Sadaaki Mori

Tomofumi Takahashi

Minoru Kitabayashi

Tetsuo Horie

Yoshiyuki Yamazaki

The power steering apparatus comprises a torque sensor for detecting a steering torque applied to a steering wheel and a steering assist motor which is driven to rotate based on the detected steering torque. The motor is driven under field weakening control in a high-speed rotation area. The motor is a brushless motor comprising a rotor having a plurality of permanent magnets which are respectively fixed in a plurality of recesses provided in a rotor core. With the electric power steering apparatus, a steer-assisting force can be obtained in high-speed steering.

Electric power steering apparatus

A brushless DC motor including a stator having plural slots; and a rotor which has plural permanent magnets and is divided into three rotor blocks in a rotation axis direction, the three rotor blocks being layered so that the arrangement angles of the rotor blocks differ from each other by an amount of a mechanical angle in a rotary direction that is equivalent to one third of a pulsation period of cogging torque generated by the rotor and stator. A brushless DC motor including a rotor having plural magnetic poles provided at an equal pitch in a circumferential direction by mounting permanent magnets in magnet mounting holes; and a stator having plural slots arranged at an equal pitch in a circumferential direction. The magnetic poles of the rotor include magnetic poles whose magnet deviation angle formed by the central line of an effective polar opening angle and the central line of the magnet mounting hole is the first angle; and magnetic poles whose magnet deviation angle is the second angle different from the first angle.

Brushless DC motor and method of manufacturing brushless DC motor

A microcomputer calculates a command value for feedback control based on a target electric current value set on the basis of steering torque and a vehicle speed, and the detecting value of a motor electric current. The microcomputer calculates the duty ratio of a PWM signal for turning on and off a switching element of a motor driving circuit from this command value. When this calculated duty ratio is 100% or less, no voltage raising circuit is operated and a battery voltage is supplied to the motor driving circuit. In contrast to this, when the calculated duty ratio Dc exceeds 100%, the microcomputer outputs the PWM signal for turning on and off the switching element of the voltage raising circuit in the duty ratio according to this excess amount. Thus, the battery voltage is raised in accordance with this excess amount and is supplied to the motor driving circuit.

Electrically operated power steering device

An electric power steering apparatus being provided with: a torque sensor for detecting a steering torque applied to a steering wheel (not shown); and a steering assisting motor driven by a drive circuit to which the voltage of a mounted battery P is applied, in which the drive circuit rotates the motor in accordance with a motor current instruction value determined based on the steering torque detected by the torque sensor , is further provided with: judging means for judging whether the motor current instruction value is higher than a first threshold value or not; boosting instruction outputting means for, when the judging means judges that the motor current instruction value is higher, outputting a boosting instruction for boosting the voltage of the mounted battery P; and a boosting circuit for boosting the voltage of the mounted battery in response to the outputted boosting instruction. Even when the voltage of the mounted battery P fluctuates, a voltage from which a stable steering assisting force is always obtained can be supplied to the steering assisting motor, so that the steering assisting motor can be reduced in size.

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Nara, Japan

Hideki Jonokuchi