Motor driving apparatus

Patent metadata

Field	Value
Publication number	US-9553535-B2
Application number	US-201314652429-A
Country	US
Kind code	B2
Filing date	Dec 19, 2013
Priority date	Dec 27, 2012
Publication date	Jan 24, 2017
Grant date	Jan 24, 2017

Abstract

A motor driving apparatus includes a rotor, a first yoke including a first magnetic portion, a first coil configured to, if energized, excite the first magnetic portion, a second yoke including a second magnetic portion, a second coil configured to, if energized, excite the second magnetic portion, a detecting portion including a first detection element, a second detection element, a third detection element, and a fourth detection element, each detection element being configured to detect a rotation position of the rotor, and a controller configured to switch a pole excited by the first magnetic portion and the second magnetic portion by switching an energization direction of the first coil and the second coil based on an output of the detecting portion.

First claim

The invention claimed is:

1. A motor driving apparatus comprising:
a rotor including a magnet, the magnet being cylindrical shaped and divided, in a peripheral direction, into sections each with an outer periphery, each section having a different polarity from adjacent sections;
a first yoke including a first magnetic portion, the first yoke being opposed to the outer periphery of the magnet;
a first coil configured to, if energized, excite the first magnetic portion;
a second yoke including a second magnetic portion, the second yoke being opposed to the outer periphery of the magnet at a position displaced by an electrical angel of 90 degrees relative to the first magnetic portion;
a second coil configured to, if energized, excite the second magnetic portion;
a detecting portion including a first detection element, a second detection element, a third detection element, and a fourth detection element, each detection element being configured to detect a rotation position of the rotor; and
a controller configured to switch a pole excited by the first magnetic portion and the second magnetic portion by switching an energization direction of the first coil and the second coil based on an output of the detecting portion,
wherein the first detection element is arranged at a position where an advance angle amount from a position at which an electrical advance angle from an excitation switching timing of each first magnetic portion is 0 degree is smaller than a delay angle amount from a position at which an electrical advance angle from an excitation switching timing of each first magnetic portion is 90 degrees if the rotor is caused to rotate in a first rotation direction and if a pole excited by the first magnetic portion is switched based on an output of the first detection element,
wherein the second detection element is arranged at a position where an advance angle amount from a position at which an electrical advance angle from an excitation switching timing of each second magnetic portion is 0 degree is smaller than a delay angle amount from a position at which an electrical advance angle from an excitation switching timing of each second magnetic portion is 90 degrees if the rotor is caused to rotate in the first rotation direction and if a pole excited by the second magnetic portion is switched based on an output of the second detection element,
wherein the third detection element is arranged at a position where an advance angle amount from a position at which an electrical advance angle from an excitation switching timing of each first magnetic portion is 0 degree is larger than a delay angle amount from a position at which an electrical advance angle from an excitation switching timing of each first magnetic portion is 90 degrees if the rotor is caused to rotate in the first rotation direction and if a pole excited by the first magnetic portion is switched based on an output of the third detection element, and
wherein the fourth detection element is arranged at a position where an advance angle amount from a position at which an electrical advance angle from an excitation switching timing of each second magnetic portion is 0 degree is larger than a delay angle amount from a position at which an electrical advance angle from an excitation switching timing of each second magnetic portion is 90 degrees if the rotor is caused to rotate in the first rotation direction and if a pole excited by the second magnetic portion is switched based on an output of the fourth detection element.

2. The motor driving apparatus according to claim 1 ,
wherein the first detection element is arranged at a position where an excitation switching timing of each first magnetic portion relative to a rotation position of the rotor falls within a range of electrical advance angles of 0 to 45 degrees if the rotor is caused to rotate in the first rotation direction and if a pole excited by the first magnetic portion is switched based on an output of the first detection element,
wherein the second detection element is arranged at a position where an excitation switching timing of each second magnetic portion relative to a rotation position of the rotor falls within a range of electrical advance angles of 0 to 45 degrees if the rotor is caused to rotate in the first rotation direction and if a pole excited by the second magnetic portion is switched based on an output of the second detection element,
wherein the third detection element is arranged at a position where an excitation switching timing of each first magnetic portion relative to a rotation position of the rotor falls within a range of electrical advance angles of 45 to 90 degrees if the rotor is caused to rotate in the first rotation direction and if a pole excited by the first magnetic portion is switched based on an output of the third detection element, and
wherein the fourth detection element is arranged at a position where an excitation switching timing of each second magnetic portion relative to a rotation position of the rotor falls within a range of electrical advance angles of 45 to 90 degrees if the rotor is caused to rotate in the first rotation direction and if a pole excited by the second magnetic portion is switched based on an output of the fourth detection element.

3. The motor driving apparatus according to claim 2 ,
wherein the first detection element is arranged at a position where an excitation switching timing of each first magnetic portion relative to a rotation position of the rotor falls within a range of electrical advance angles of 45 to 90 degrees if the rotor is caused to rotate in a second rotation direction, which is a reverse direction to the first rotation direction, and if a pole excited by the first magnetic portion is switched based on an output of the first detection element,
wherein the second detection element is arranged at a position where an excitation switching timing of each second magnetic portion relative to a rotation position of the rotor falls within a range of electrical advance angles of 45 to 90 degrees if the rotor is caused to rotate in the second rotation direction and if a pole excited by the second magnetic portion is switched based on an output of the second detection element,
wherein the third detection element is arranged at a position where an excitation switching timing of each first magnetic portion relative to a rotation position of the rotor falls within a range of electrical advance angles of 0 to 45 degrees if the rotor is caused to rotate in the second rotation direction and if a pole excited by the first magnetic portion is switched based on an output of the third detection element, and
wherein the fourth detection element is arranged at a position where an excitation switching timing of each second magnetic portion relative to a rotation position of the rotor falls within a range of electrical advance angles of 0 to 45 degrees if the rotor is caused to rotate in the second rotation direction and if a pole excited by the second magnetic portion is switched based on an output of the fourth detection element.

4. The motor driving apparatus according to claim 1 , further comprising:
a speed detecting portion,
wherein the controller switches an energization direction of the first coil based on an output of the first detection element and an energization direction of the second coil based on an output of the second detection element if the rotor is caused to rotate in the first rotation direction and if a rotation speed of the rotor detected by the speed detecting portion is less than a predetermined rotation speed,
wherein the controller switches an energization direction of the first coil based on an output of the third detection element and an energization direction of the second coil based on an output of the fourth detection elemen

Assignees

• Canon Kk

Inventors

• Aoshima Chikara

Classifications

• H02P8/06

  in selected direction of rotation · CPC title

• H02P8/12 Primary

  Control or stabilisation of current · CPC title

• H02K11/215

  Magnetic effect devices, e.g. Hall-effect or magneto-resistive elements · CPC title

• H02P8/14 Primary

  Arrangements for controlling speed or speed and torque (H02P8/12, H02P8/22 take precedence) · CPC title

• H02K29/08

  using magnetic effect devices, e.g. Hall-plates, magneto-resistors (H02K29/12 takes precedence) · CPC title