Abstract: The disclosure concerns a a motor drive apparatus, an electric actuator and an electric power steering apparatus capable of continuous torque control up to the high drive speed and high torque area, in order to enable quick acceleration and deceleration. A controller comprises a voltage saturation detecting apparatus for detecting the voltage saturation of the output voltage of an inverter circuit, based on the battery voltage, and a waveform controller that converts the drive waveform of the inverter circuit into the waveform created by superimposing harmonics of high odd-numbered order on a sinusoidal wave as a fundamental wave of the modulated wave modulated by a PWN carrier wave; and continuously changes the ratio of superimposing the high-order harmonics in response to the voltage saturation detected by a voltage saturation detecting means. This arrangement allows the controller to continuously change the drive waveform of the inverter circuit.

Abstract: A rotary sensor that outputs two analog signals, such as one sine wave and one cosine wave and has multiple periods within one period of the electrical angle of a motor is employed. The motor is energized at each position for a specified length of time upon its startup by using multiple electrical angles corresponding to the multiple candidate absolute angles obtained from the rotary sensor signal as the initial position of the motor, and the electrical angle at which the motor acceleration becomes maximum is determined as the absolute angle. While the motor drive is in operation, on the other hand, the phase difference ?? between the phase of the motor at the counter electromotive voltage and the control phase is directly computed from the parameters of the motor, sensed current, voltage command and angle speed so as to correct the shifted position.

Abstract: A magnetic disk drive includes a base constituting at least a face included in an enclosure; a shaft secured to the base; a rotor which rotates around the shaft as a rotary axis; a stator for rotating the rotor; and a magnetic disk secured to the rotor; wherein the stator is disposed on a face facing the base. This improves durability of the magnetic disk drive.

Abstract: In an operation range of an actuator subjected to quick acceleration and deceleration, a motor drive apparatus, an electric actuator and an electric power steering apparatus capable of continuous torque control up to the high drive speed and high torque area. A controller comprises a voltage saturation detecting means for detecting the voltage saturation of the output voltage of an inverter circuit, based on the battery voltage, and a waveform controller that converts the drive waveform of the inverter circuit into the waveform created by superimposing harmonics of high odd-numbered order on a sinusoidal wave as a fundamental wave of the modulated wave modulated by a PWN carrier wave; and continuously changes the ratio of superimposing the high-order harmonics in response to the voltage saturation detected by a voltage saturation detecting means. This arrangement allows the controller to continuously change the drive waveform of the inverter circuit.

Abstract: A disk drive comprising a rotor, to which a disk and a plurality of magnets are fixed, and an open-slot type integrally molded stator disposed about an outer periphery of the magnets, and wherein the stator comprises coils formed by etching metallic films on teeth. The invention may also be applied to a closed-slot type stator. With either type, it is possible to produce an opening that is equal to or smaller than the thickness of a coil wire and cogging torque is minimized.

Abstract: An object of the invention is to inhibit a turning force of a magnetic disc apparatus from being reduced. In order to achieve the object, there is provided a magnetic disc apparatus having a rotor to which a magnetic disc fixed, and a stator which is filled with a resin between stator coils, wherein a member having a lower expansion coefficient than a thermal expansion coefficient of the resin is arranged between the stator coils.

Abstract: A disk drive comprising a rotor, to which a disk and a plurality of magnets are fixed, and an open-slot type integrally molded stator disposed about an outer periphery of the magnets, and wherein the stator comprises coils formed by etching metallic films on teeth. The invention may also be applied to a closed-slot type stator. With either type, it is possible to produce an opening that is equal to or smaller than the thickness of a coil wire and cogging torque is minimized.

Abstract: An object of the invention is to inhibit a turning force of a magnetic disc apparatus from being reduced. In order to achieve the object, there is provided a magnetic disc apparatus having a rotor to which a magnetic disc fixed, and a stator which is filled with a resin between stator coils, wherein a member having a lower expansion coefficient than a thermal expansion coefficient of the resin is arranged between the stator coils.

Abstract: A magnetic disk drive includes a base constituting at least a face included in an enclosure; a shaft secured to the base; a rotor which rotates around the shaft as a rotary axis; a stator for rotating the rotor; and a magnetic disk secured to the rotor; wherein the stator is disposed on a face facing the base. This improves durability of the magnetic disk drive.

Abstract: A controlling apparatus controls a suction performance of a blower motor which is installed into a cleaner main body. The controlling apparatus increases the suction performance when a suction nozzle is operated and decreases the suction performance when the suction nozzle is stopped. Corresponding to a floor use suction nozzle and a crevice use suction nozzle, at a predetermined air flow amount range, the most suitable operation control being suited to a discriminated suction nozzle can carried out automatically. Plural kinds of the suction nozzles at an actual use scope are set beforehand. When the suction nozzle is exchanged the flow amount range is changed over and selected with a respective suction nozzle. Plural kinds of the suction nozzles are selected and changed over automatically according to the dimension of a change amount of an operation condition. A brushless direct motor is used as the blower motor and has a domain being operated at a chopper control duty of factor 100%.

Abstract: In a vacuum cleaner, both static pressure H.sub.data and a variation width .DELTA.H in the static pressure appearing when a suction port is operated are detected from a pressure sensor provided at a rear side of a filter within a main body of the vacuum cleaner; a current variation width .DELTA.pbi appearing when the suction port is operated is detected from a current of a nozzel motor for driving a rotary brush stored in a power brush suction port; an air quantity at the suction port is calculated from the current, rotational speed of a fan motor and static pressure; command values are newly obtained by performing a fuzzy calculation with the variation width .DELTA.pbi, static-pressure command value Hcmd; the variation width .DELTA.H and the static-pressure command value Qcmd; the variation width .DELTA.pbi and static-pressure command value Hcmd; and also the variation width .DELTA.