Abstract: When a vehicle is quickly steered while the vehicle is travelling at an extremely low speed, a load on an in-vehicle power supply is reduced without deteriorating a steering feeling by reducing a motor driving current. A steering speed is compared with a threshold. When the steering speed is lower than the threshold, the process proceeds to step S6. In step S6, a voltage value of a battery power supply, which is used as a prescribed value, is set as a limit voltage in order to reduce a motor consumption current. When the steering speed is higher than the threshold, a value “V0/n” lower than the prescribed value is set as the limit voltage to reduce a consumption current when the steering wheel is steered without driving. “n” is “delay adjustment parameter”, and is a real number that exceeds 1.

Abstract: Sinusoidal signals (S1, S2) having a phase difference of 120° are output from two magnetic sensors in accordance with rotation of an input shaft. A first rotation angle computation unit computes a rotation angle ?(n) on the basis of output signals S1(n), S1(n?1), S2(n), S2(n?1) from the magnetic sensors, which are sampled at two sampling timings. At this time, the first rotation angle computation unit computes the rotation angle ?(n) on the assumption that there are no variations of amplitudes of the output signals (S1, S2) from each one of the two sensors due to temperature changes between the two sampling timings.

Abstract: In a warning device for a vehicle, a basic target current value setting unit sets a basic target current value based on a steering torque and a vehicle speed. When a lane deviation determining unit determines that there is a high possibility that a vehicle will deviate from a lane, a warning vibration wave generator generates a warning vibration wave containing a plurality of frequency components. A target current value is computed by adding the warning vibration wave to the basic target current value. A motor current to be applied to an electric motor is controlled so as to approach the target current value.

Abstract: In a warning device for a vehicle, a basic target current value setting unit sets a basic target current value based on a steering torque and a vehicle speed. When a lane deviation determining unit determines that there is a high possibility that a vehicle will deviate from a lane, a warning vibration wave generator generates a warning vibration wave containing a plurality of frequency components. A target current value is computed by adding the warning vibration wave to the basic target current value. A motor current to be applied to an electric motor is controlled so as to approach the target current value.

Abstract: Sinusoidal signals (S1, S2) having a phase difference of 120° are output from two magnetic sensors in accordance with rotation of an input shaft. A first rotation angle computation unit computes a rotation angle ?(n) on the basis of output signals S1(n), S1(n?1), S2(n), S2(n?1) from the magnetic sensors, which are sampled at two sampling timings. At this time, the first rotation angle computation unit computes the rotation angle ?(n) on the assumption that there are no variations of amplitudes of the output signals (S1, S2) from each one of the two sensors due to temperature changes between the two sampling timings.

Abstract: A controller applies slight rotational torque to a drive gear of a reduction mechanism also in a predetermined range in which a motor does not produce any steering operation assist force. That is, the motor is caused to produce slight rotational torque not enough to drive a driven gear, and the rotational torque direction is reversed under a given condition. Accordingly, a backlash between the drive gear and the driven gear is eliminated.

Abstract: An electric power steering system includes a motor that applies assist force to a steering system, and updates a motor resistance (Rm) that is a value indicating a resistance of the motor. Specifically, the motor resistance (Rm) is updated on the basis of the fact that an induced voltage (EX) of the motor is smaller than a first determination value (GA). In addition, when the induced voltage (EX) is smaller than or equal to a second determination value (GB), a divided value that is obtained by dividing a motor voltage (Vm) by a motor current (Im) is set as a new motor resistance (Rm).

Abstract: A controller applies slight rotational torque to a drive gear of a reduction mechanism also in a predetermined range in which a motor does not produce any steering operation assist force. That is, the motor is caused to produce slight rotational torque not enough to drive a driven gear, and the rotational torque direction is reversed under a given condition. Accordingly, a backlash between the drive gear and the driven gear is eliminated.

Abstract: An electric power steering system includes a motor that applies assist force to a steering system, and updates a motor resistance (Rm) that is a value indicating a resistance of the motor. Specifically, the motor resistance (Rm) is updated on the basis of the fact that an induced voltage (EX) of the motor is smaller than a first determination value (GA). In addition, when the induced voltage (EX) is smaller than or equal to a second determination value (GB), a divided value that is obtained by dividing a motor voltage (Vm) by a motor current (Im) is set as a new motor resistance (Rm).

Abstract: A steering shaft is composed of an upper shaft, a lower shaft, an input shaft, and an output shaft. The upper shaft, the lower shaft, and the input shaft can rotate together, and the input shaft and the output shaft are relatively rotatably coupled to each other via a torsion bar. The rotational position of a rotor coupled to the output shaft is calculated based on the detected rotational position of the lower shaft and a steering torque detected based on the amount of relative rotational displacement of the input shaft and the output shaft. Thus, it is not necessary to include a rotor rotational position detecting unit for detecting the rotational position of the rotor within the electric motor, which reduces the size of the electric motor.

Abstract: A current sensor of a motor controller detects the current applied to a motor drive circuit and thus a phase where a failure cannot be detected would occur without taking any measures. However, an abnormal current monitor section contained in a microcomputer receives a voltage signal of an average value of the currents detected in the current sensor by allowing a signal to pass through a first LPF having a cutoff frequency sufficiently lower than the frequency of a PWM signal. Therefore, whether or not the value is within a predetermined normal range is checked, whereby whether or not some failure containing a failure of the current sensor occurs can be easily determined about every phase.

Abstract: In an energy absorbing steering system including a steering shaft to which a steering member is coupled, and a steering column that rotatably supports the steering shaft, at least one of the steering shaft and the steering column includes an impact absorbing portion that contracts when a load equal to or higher than a predetermined value is applied, and the impact absorbing portion includes a first impact absorbing portion having a first impact absorption load, and a second impact absorbing portion having a second impact absorption load different from the first impact absorption load.

Abstract: A vehicle steering apparatus includes a jacket for rotatably supporting a steering shaft, and an electric motor. The electric motor includes an annular rotor arranged coaxially with the steering shaft and rotating together with the steering shaft. The jacket includes a tubular upper jacket and a tubular lower jacket that are fitted into each other and are moved axially relative to each other in the collision of a vehicle. An annular space surrounding the steering shaft is provided radially inside the rotor. A part of the upper jacket enters the annular space in the collision of the vehicle.

Abstract: An electric power steering apparatus includes a steering assisting electric motor having a motor housing for accommodating an annular rotor and an annular stator. The rotor and the stator are disposed coaxially with a steering shaft. The motor housing is supported by a support member mounted to a vehicle body member. A shock applied to a steering member when the motor vehicle crashes is absorbed by the relative movement between the motor housing and the support member.

Abstract: A current sensor of a motor controller detects the current applied to a motor drive circuit and thus a phase where a failure cannot be detected would occur without taking any measures. However, an abnormal current monitor section contained in a microcomputer receives a voltage signal of an average value of the currents detected in the current sensor by allowing a signal to pass through a first LPF having a cutoff frequency sufficiently lower than the frequency of a PWM signal. Therefore, whether or not the value is within a predetermined normal range is checked, whereby whether or not some failure containing a failure of the current sensor occurs can be easily determined about every phase.

Abstract: A steering shaft is composed of an upper shaft, a lower shaft, an input shaft, and an output shaft. The upper shaft, the lower shaft, and the input shaft can rotate together, and the input shaft and the output shaft are relatively rotatably coupled to each other via a torsion bar. The rotational position of a rotor coupled to the output shaft is calculated based on the detected rotational position of the lower shaft and a steering torque detected based on the amount of relative rotational displacement of the input shaft and the output shaft. Thus, it is not necessary to include a rotor rotational position detecting unit for detecting the rotational position of the rotor within the electric motor, which reduces the size of the electric motor.

Abstract: In an energy absorbing steering system including a steering shaft to which a steering member is coupled, and a steering column that rotatably supports the steering shaft, at least one of the steering shaft and the steering column includes an impact absorbing portion that contracts when a load equal to or higher than a predetermined value is applied, and the impact absorbing portion includes a first impact absorbing portion having a first impact absorption load, and a second impact absorbing portion having a second impact absorption load different from the first impact absorption load.

Abstract: A vehicle steering apparatus includes a jacket for rotatably supporting a steering shaft, and an electric motor. The electric motor includes an annular rotor arranged coaxially with the steering shaft and rotating together with the steering shaft. The jacket includes a tubular upper jacket and a tubular lower jacket that are fitted into each other and are moved axially relative to each other in the collision of a vehicle. An annular space surrounding the steering shaft is provided radially inside the rotor. A part of the upper jacket enters the annular space in the collision of the vehicle.

Abstract: An electric power steering apparatus includes a steering assisting electric motor having a motor housing for accommodating an annular rotor and an annular stator. The rotor and the stator are disposed coaxially with a steering shaft. The motor housing is supported by a support member mounted to a vehicle body member. A shock applied to a steering member when the motor vehicle crashes is absorbed by the relative movement between the motor housing and the support member.