Abstract: A motor drive control device has a control circuit that generates a drive control signal for controlling a rotational speed of a motor based on a speed command signal indicating a target rotational speed of the motor, and a motor driving unit that drives the motor based on the drive control signal. The control circuit performs speed feedback control for generating the drive control signal so that the rotational speed of the motor coincides with the target rotational speed when the target rotational speed is lower than a rotational speed threshold value, and generates the drive control signal based on a relationship between current flowing through the motor and a reference current value when the target rotational speed is higher than the rotational speed threshold value.

Abstract: A motor drive control device has a control circuit that generates a drive control signal for controlling a rotational speed of a motor based on a speed command signal indicating a target rotational speed of the motor, and a motor driving unit that drives the motor based on the drive control signal. The control circuit performs speed feedback control for generating the drive control signal so that the rotational speed of the motor coincides with the target rotational speed when the target rotational speed is lower than a rotational speed threshold value, and generates the drive control signal based on a relationship between current flowing through the motor and a reference current value when the target rotational speed is higher than the rotational speed threshold value.

Abstract: A fan device 1 includes a second housing 12 and a hub 27. The hub 27 includes a hub body part 272 and a hub outer peripheral wall part 271. The hub body part 272 is a surface extending in the radial direction orthogonal to the direction of the axis x, and the hub body part 272 covers the motor 20 from the upper side “a” in the direction of an axis c. The hub outer peripheral wall part 271 extends from the end portion of the hub body part 272 toward the lower side “b” from the upper side “a” in the direction of the axis x. Assuming that the outer diameter of the outer peripheral surface of the hub outer peripheral wall part 271 is “a1”, and the outer diameter of the outer peripheral surface of the base outer peripheral wall part 124 is “b1”, 1.05<b1/a1<1.13 is established.

Abstract: A motor drive control device capable of reducing the occurrence of vibration in a simple circuit configuration is provided. The motor drive control device (1) includes a motor drive unit (2) that selectively energizes coils with a plurality of phases (Lu, Lv and Lw) of a motor (20) and a control circuit (4) that outputs a drive control signal (Sd) which is a PWM signal to the motor drive unit (2) and thereby controls driving of the motor (20) while switching energization phases of the coils with the plurality of phases (Lu, Lv and Lw) energized by the motor drive unit (2) in predetermined order. The control circuit (4) executes reduction control to temporarily reduce a duty ratio of the drive control signal (Sd) every time a period of 1/m (m is an integer of 2 or more) of a switching cycle of the energization phases elapses after switching the energization phases.

Abstract: A fan device 1 includes a second housing 12 and a hub 27. The hub 27 includes a hub body part 272 and a hub outer peripheral wall part 271. The hub body part 272 is a surface extending in the radial direction orthogonal to the direction of the axis x, and the hub body part 272 covers the motor 20 from the upper side “a” in the direction of an axis c. The hub outer peripheral wall part 271 extends from the end portion of the hub body part 272 toward the lower side “b” from the upper side “a” in the direction of the axis x. Assuming that the outer diameter of the outer peripheral surface of the hub outer peripheral wall part 271 is “a1”, and the outer diameter of the outer peripheral surface of the base outer peripheral wall part 124 is “b1”, 1.05<b1/a1<1.13 is established.

Abstract: A motor drive control device has a control circuit that generates a drive control signal for controlling a rotational speed of a motor based on a speed command signal indicating a target rotational speed of the motor, and a motor driving unit that drives the motor based on the drive control signal. The control circuit performs speed feedback control for generating the drive control signal so that the rotational speed of the motor coincides with the target rotational speed when the target rotational speed is lower than a rotational speed threshold value, and generates the drive control signal based on a relationship between current flowing through the motor and a reference current value when the target rotational speed is higher than the rotational speed threshold value.

Abstract: A motor drive control device capable of reducing the occurrence of vibration in a simple circuit configuration is provided. The motor drive control device (1) includes a motor drive unit (2) that selectively energizes coils with a plurality of phases (Lu, Lv and Lw) of a motor (20) and a control circuit (4) that outputs a drive control signal (Sd) which is a PWM signal to the motor drive unit (2) and thereby controls driving of the motor (20) while switching energization phases of the coils with the plurality of phases (Lu, Lv and Lw) energized by the motor drive unit (2) in predetermined order. The control circuit (4) executes reduction control to temporarily reduce a duty ratio of the drive control signal (Sd) every time a period of 1/m (m is an integer of 2 or more) of a switching cycle of the energization phases elapses after switching the energization phases.

Abstract: A motor drive control device drives a motor including a plurality of phase coils and a rotor rotatably supported with respect to the plurality of phase coils, and the motor drive control device includes a controller, which generates a drive control signal; a motor driver, which outputs a drive signal to each of the phase coils of the motor, based on the drive control signal; and a back-electromotive-voltage detector, which is connected to each of the phase coils and includes resistive voltage dividing circuits having respectively different voltage-dividing ratios, wherein the back-electromotive-voltage detector detects a rotational position of a rotor for sensorless driving by using the resistive voltage dividing circuits.

Abstract: A motor drive controller includes: a motor driver that applies a voltage to each phase of a motor to rotate; a rotational position detector that detects rotational position of the motor and generates rotational position information indicating the rotational position; and a controller that outputs, to the motor driver, driving control signals for repeatedly adjusting an advance angle and a lag angle at energization switching of the each phase of the motor in a prescribed pattern based on the rotational position information generated by the rotational position detector.

Abstract: A motor drive control device drives a motor including a plurality of phase coils and a rotor rotatably supported with respect to the plurality of phase coils, and the motor drive control device includes a controller, which generates a drive control signal; a motor driver, which outputs a drive signal to each of the phase coils of the motor, based on the drive control signal; and a back-electromotive-voltage detector, which is connected to each of the phase coils and includes resistive voltage dividing circuits having respectively different voltage-dividing ratios, wherein the back-electromotive-voltage detector detects a rotational position of a rotor for sensorless driving by using the resistive voltage dividing circuits.

Abstract: A motor drive controller includes: a motor driver that applies a voltage to each phase of a motor to rotate; a rotational position detector that detects rotational position of the motor and generates rotational position information indicating the rotational position; and a controller that outputs, to the motor driver, driving control signals for repeatedly adjusting an advance angle and a lag angle at energization switching of the each phase of the motor in a prescribed pattern based on the rotational position information generated by the rotational position detector.

Abstract: A single-phase brushless motor has both superior start-up stability and low cogging torque. In the outer-rotor-type single-phase brushless motor, when a gap width between the rotor and one edge of the salient pole surface is defined as d1, a gap width between the rotor and the other edge of the salient pole surface is defined as d2, and a minimum gap width between the rotor and the salient pole surface is defined as d3, the formula d3<d1<d2 is satisfied, and the gap width is d3 at a position shifted toward the one edge of the salient pole surface from the center of the arc shape which forms the salient pole surface.

Abstract: A disk driving apparatus includes a base member, a hub member, and a fluid bearing unit. The base member has a head movement region on which a head unit is to be mounted such that a head portion of the head unit can be moved along the radial direction of a recording face in a reciprocating manner while facing the recording face of a recording disk to be mounted on the hub member, and a recessed housing portion housing the fluid bearing unit such that it surrounds at least a part of a rotor unit supported by the fluid bearing unit. Furthermore, the base member has an inhibiting wall at a boundary between the head movement region and the recessed housing portion so as to prevent a lubricant fluid from migrating toward the recording disk side.

Abstract: A sleeve supports a shaft. A housing member is arranged so as to surround the sleeve and make the end of the sleeve protrude. A base member holds the housing member and fixes a stator core so as to surround the housing member. A hub drives a recording disk by being rotated integrally with the shaft, with a magnet being fixed to an annular portion concentric with the shaft so as to face the stator core fixed to the base member. A thrust member is rotated integrally with the hub, and a descender portion and a ring portion.

Abstract: A disk driving apparatus includes a base member, a hub member, and a fluid bearing unit. The base member has a head movement region on which a head unit is to be mounted such that a head portion of the head unit can be moved along the radial direction of a recording face in a reciprocating manner while facing the recording face of a recording disk to be mounted on the hub member, and a recessed housing portion housing the fluid bearing unit such that it surrounds at least a part of a rotor unit supported by the fluid bearing unit. Furthermore, the base member has an inhibiting wall at a boundary between the head movement region and the recessed housing portion so as to prevent a lubricant fluid from migrating toward the recording disk side.

Abstract: A single-phase brushless motor has both superior start-up stability and low cogging torque. In the outer-rotor-type single-phase brushless motor, when a gap width between the rotor and one edge of the salient pole surface is defined as d1, a gap width between the rotor and the other edge of the salient pole surface is defined as d2, and a minimum gap width between the rotor and the salient pole surface is defined as d3, the formula d3<d1<d2 is satisfied, and the gap width is d3 at a position shifted toward the one edge of the salient pole surface from the center of the arc shape which forms the salient pole surface.

Abstract: A disk driving apparatus includes a base member, a hub member, and a fluid bearing unit. The base member has a head movement region on which a head unit is to be mounted such that a head portion of the head unit can be moved along the radial direction of a recording face in a reciprocating manner while facing the recording face of a recording disk to be mounted on the hub member, and a recessed housing portion housing the fluid bearing unit such that it surrounds at least a part of a rotor unit supported by the fluid bearing unit. Furthermore, the base member has an inhibiting wall at a boundary between the head movement region and the recessed housing portion so as to prevent a lubricant fluid from migrating toward the recording disk side.

Abstract: A sleeve supports a shaft. A housing member is arranged so as to surround the sleeve and make the end of the sleeve protrude. A base member holds the housing member and fixes a stator core so as to surround the housing member. A hub drives a recording disk by being rotated integrally with the shaft, with a magnet being fixed to an annular portion concentric with the shaft so as to face the stator core fixed to the base member. A thrust member is rotated integrally with the hub, and a descender portion and a ring portion.

Abstract: A sleeve supports a shaft. A housing member is arranged so as to surround the sleeve and make the end of the sleeve protrude. A base member holds the housing member and fixes a stator core so as to surround the housing member. A hub drives a recording disk by being rotated integrally with the shaft, with a magnet being fixed to an annular portion concentric with the shaft so as to face the stator core fixed to the base member. A thrust member is rotated integrally with the hub, and a descender portion and a ring portion.

Abstract: A disk driving apparatus includes a base member, a hub member, and a fluid bearing unit. The base member has a head movement region on which a head unit is to be mounted such that a head portion of the head unit can be moved along the radial direction of a recording face in a reciprocating manner while facing the recording face of a recording disk to be mounted on the hub member, and a recessed housing portion housing the fluid bearing unit such that it surrounds at least a part of a rotor unit supported by the fluid bearing unit. Furthermore, the base member has an inhibiting wall at a boundary between the head movement region and the recessed housing portion so as to prevent a lubricant fluid from migrating toward the recording disk side.