Abstract: The invention provides an electric power steering apparatus which can detect a ground fault of an angular resolver without fault. Values of a first resistance (R1), a second resistance (R2), a third resistance (R3) and a fourth resistance (R4) are set such that a difference between a minimum output potential (Vout Min) of a first differential amplifier (OP1) at a time when an angular resolver is not in a ground fault which may be generated on the basis of a dispersion of the first resistance (R1), the second resistance (R2), the third resistance (R3) and the fourth resistance (R4), and a direct-current resistance component (Rdc) of the angular resolver, and a maximum potential (Vout Max) at a time when the angular resolver is in the ground fault becomes equal to or more than a predetermined margin for preventing an erroneous ground fault detection in a CPU (62) side.

Abstract: The invention provides an electric power steering apparatus in which a dead zone is not generated even at a low duty ratio while slow starting a switching element. When a duty ratio of a PWM control becomes more than a preset value (NO in S14), a switching cycle is set to a predetermined value (a fixed value) (S20). When the duty ratio becomes equal to or less than the preset value (Yes in S14), the switching cycle is made longer than the predetermined value (S16). It is possible to securely apply a current to a motor and it is possible to prevent a dead zone from being generated, by elongating the switching cycle even in a low duty ratio while slow starting an FET and preventing a noise from being generated.

Abstract: An electric power steering apparatus has a motor controlled so as to generate steering assist power according to the steering torque required to operate a steering wheel. As a result of correction of the output of the motor in accordance with a value correlating with the rotation angular velocity correspondence value of the steering wheel, in the frequency response characteristic represented by the steering frequency of the steering wheel and the amplitude ratio of the steering torque relative to the steering angle of the steering wheel, the amplitude ratio is set within a setting range, at least within the steering frequency range when a person operates the steering wheel.

Abstract: A variable gear ratio hydraulic power steering device 1 is provided with a variable ratio transmission mechanism 7 having a drive motor 70; a flow volume control valve 41 for controlling the discharge flow volume of an oil pump 10 which circulates operating fluid; and a steering angle sensor 310 for measuring a handle steering angle input to a steering handle 31. A valve controlling controller 50 is constructed to take thereinto a measured ACT angle which is the rotational angle of the drive motor 70 and to calculate a target ACT angle for the drive motor 70 based on the handle steering angle. Further, the valve controlling controller 50 controls the flow volume control valve 41 to make the discharge flow volume equal to or greater than a predetermined flow volume when the magnitude of a difference ACT angle which is the difference between the target ACT angle and the measured ACT angle is equal to or greater than a threshold value.

Abstract: A controller for a brushless motor that suppresses torque reduction resulting from the influence of motor inductance and suppresses the generation of invalid current. A phase advancing angle calculator calculates a delay angle of phases of phase currents with respect to the phases of the phase voltage command and a phase advancing angle corresponding to the delay angle based on the function of the angular velocity and the motor inductance (and armature winding resistance) of the brushless motor. An adder adds the phase advancing angle to the rotation angle provided from the rotation angle calculator to generate the corrected rotation angle. The adder further provides the corrected rotation angle to a two-phase/three-phase converter.

Abstract: A motor control device 1 is provided with a neutral point shift section 11. The neutral point shift section 11 shifts a neutral point (command neutral point) of phase voltage commands Vu0*, Vv0*, Vw0* so that the values of the phase voltage commands Vu1*, Vv1*, Vw1* after the shifting of the neutral point come within the amplitude Vc of a triangular wave (triangular wave signal), and inputs the phase voltage commands Vu1*, Vv1*, Vw1* with the neutral point having been shifted, to a control signal output section 8. Thus, the motor control device 1 is enabled to heighten the output voltage without bringing about increase in manufacturing cost and substantial delay in calculation interval.

Abstract: In a ball screw mechanism, in order to eliminate a step on a joint between respective one ends of a female screw groove of a nut and a circulation groove of a ball circulation piece, a ball end mill of the diameter equal to or larger than balls is moved along the female screw groove to machine a joint area between the respective one ends of the female screw groove and the circulation groove. During the movement of the ball end mill, the infeed depth of the ball end mill into the machined surface is gradually increased so that an acute angle is formed as the angle formed by the boundary lines between a finished surface and an unfinished surface at both flanks of the female screw groove.

Abstract: This invention provides a resolver signal processing method and apparatus capable of enlarging an appropriate computation possible range and relaxing the installation accuracy of mechanical components which constitute a resolver and its surroundings. The electrically-powered steering apparatus obtains a steering torque and a steering angle within an allowable input range of those inputted into a first resolver and a second resolver based on a real zero point ? and further, a steering torque and a steering angle out of the allowable input range of those inputted to the first resolver and the second resolver based on (+) virtual zero point ? and (?) virtual zero point ?, which are set to a different value from the real zero point ?.

Abstract: An electric motor is disclosed wherein a positive magnetic pole winding and a negative magnetic winding for each of plural phases in each of two systems are wound respectively around two teeth adjoining each other of those teeth which are arranged circumferentially on an internal surface of a stator to protrude radially inwardly. Thus, in either one of the case that the rotor is rotated by the excitation of all the windings in both of the two systems and the case that it is rotated by the excitation of the windings in either one of the two systems, the windings adjoining each other serve as a set and magnetically attract the rotor thereby to rotate the same. In either case, the position sensor is able to precisely detect the position of the rotor relative to the windings.

Abstract: The present invention intends to provide a variable reluctance-type resolver which does not deteriorate detecting accuracy, and which can fix the rotor to the rotate shaft cheaply. For such purpose, the resolver 1 is comprised of a stator 5 on which coils 6 are wound, a rotor provided with protrude poles 4a, an annular stopper 10 made of magnetic material. An outer diameter DS of the stopper 10 is selected to be smaller than a valley diameter DR of the rotor 4. Leakage of the magnetic flux from the stator to the stopper is prevented, and stopper made of the magnetic material can fix the rotor in cheaper way.

Abstract: A trouble determining apparatus for a chopper type DC boosting circuit capable of determining whether or not a switching device is in trouble securely and quickly and when the switching circuit is in trouble, preventing other circuit from being in a trouble. Upon determining a short-circuit trouble of a transistor Q, a boosting circuit control unit 22 is turned OFF a power relay RL and then determines whether or not a voltage VP1 of a connecting point P1 rises over a first set voltage VS1 by the time when a first predetermined time t1 elapses since an ignition switch IG is turned ON with the transistor Q set to OFF.