Patent Description:
Conventionally, there is a rotation detector that detects rotation of a rotary shaft of a motor. For example, Patent Literature <NUM> discloses a rotation detector including a disk-shaped magnet provided on a shaft, and three power generators configured by a magnetic wire and a pickup coil, in which each of the three power generators is disposed on one of a plurality of sides of a virtual triangle formed on an end surface side of the magnet.

<CIT> discloses an encoder device comprising: a position detecting portion which detects position information of a moving portion; magnets having a plurality of polarities in a movement direction of the moving portion; an electrical signal generating portion which includes a magneto sensitive portion having a magnetic characteristic which varies in accordance with variation of a magnetic field accompanying the movement of the moving portion, and a first magnetic body for guiding magnetic flux lines of the magnets to the magneto sensitive portion, and which generates an electrical signal on the basis of the magnetic characteristic of the magneto sensitive portion; and a second magnetic body which is disposed between the magnets and the magneto sensitive portion to guide the magnetic flux lines of a part of the magnets having one polarity to a part of the magnets having another polarity.

<CIT> and <CIT> are further examples of prior art related with the application.

However, in the rotation detector in Patent Literature <NUM>, there is a problem that the power generated by the power generator cannot be appropriately supplied, and erroneous detection occurs.

The present disclosure has been made to solve such a problem, and an object thereof is to provide a rotation detector and a rotation detection method capable of suppressing the occurrence of erroneous detection.

A rotation detector according to one aspect of the present disclosure includes a magnet that rotates together with a rotary shaft; a plurality of power generation elements that generate power according to a change in a magnetic field due to rotation of the magnet together with the rotary shaft; and a plurality of magnetic sensors each provided to a corresponding one of the plurality of power generation elements, whereby each of the plurality of magnetic sensors is disposed at the same location as the corresponding one of the plurality of power generation elements. The rotation detector further includes an information processor that determines a rotational position of the rotary shaft by using the plurality of magnetic sensors; and a generated power supply unit that supplies power generated by each of the plurality of power generation elements only to the corresponding one of the plurality of magnetic sensors.

A rotation detection method according to one aspect of the present disclosure is a rotation detection method using a rotation detector. The rotation detector includes a magnet that rotates together with a rotary shaft, a plurality of power generation elements that generate power according to a change in a magnetic field due to rotation of the magnet together with the rotary shaft, a plurality of magnetic sensors each provided to a corresponding one of the plurality of power generation elements, and a generated power supply unit that supplies power generated by each of the plurality of power generation elements only to the corresponding one of the plurality of power generation elements. The rotation detection method includes determining in which region among a plurality of regions arranged in a rotation direction of the rotary shaft a reference position in the rotation direction of the rotary shaft is located, based on power generation information indicating a power generation element that has generated power among the plurality of power generation elements and detection information indicating a detection result from a magnetic sensor corresponding to the power generation element among the plurality of magnetic sensors; and storing a region in which the reference position is determined to be located among the plurality of regions.

According to the present disclosure, it is possible to provide a rotation detector and a rotation detection method capable of suppressing the occurrence of erroneous detection.

Hereinafter, exemplary embodiments of the present disclosure will be described. Note that all the exemplary embodiments described below show one specific example of the present disclosure. Therefore, numerical values, constituent elements, disposition positions and connection modes of the constituent elements, and steps, order of the steps, and the like illustrated in the following exemplary embodiments are merely examples, and are not intended to limit the present disclosure. Thus, among the constituent elements in the following exemplary embodiments, constituent elements that are not described in independent claims indicating the highest concept of the present disclosure are described as optional constituent elements.

Each of the drawings is a schematic view, and is not necessarily precisely illustrated. Note that, in all the drawings, substantially the same configurations are denoted by the same reference numerals, and redundant description will be omitted or simplified.

<FIG> is a diagram illustrating motor <NUM> including rotation detector <NUM> according to a first exemplary embodiment. <FIG> is a diagram illustrating substrate <NUM> and rotary plate <NUM> of rotation detector <NUM> in <FIG>. Part (a) of <FIG> illustrates substrate <NUM>, and part (b) of <FIG> illustrates rotary plate <NUM>. In <FIG>, case <NUM>, magnet <NUM>, and reflection pattern <NUM> are illustrated in a cross section. In <FIG>, power generation element <NUM> and control circuit <NUM> illustrated in <FIG> are not illustrated. In <FIG>, optical sensor <NUM> illustrated in <FIG> is not illustrated.

As illustrated in <FIG>, motor <NUM> includes main body <NUM>, rotor <NUM>, stator <NUM>, rotary shaft <NUM>, case <NUM>, and rotation detector <NUM>. A rotation axis line direction is a direction in which rotation axis line A of rotary shaft <NUM> extends (refer to an arrow X in <FIG>).

Rotor <NUM> and stator <NUM> are accommodated in main body <NUM>. Rotor <NUM> rotates about stator <NUM>.

Rotary shaft <NUM> extends in the rotation axis line direction and has a rod shape such as a columnar shape. The axis of rotary shaft <NUM> and rotation axis line A coincide with each other. Rotary shaft <NUM> is fixed to rotor <NUM> and rotates about rotation axis line A. For example, when power is supplied to motor <NUM>, rotary shaft <NUM> rotates about rotation axis line A together with rotor <NUM> based on the power. A rotation direction of rotary shaft <NUM> (refer to an arrow Z in <FIG>) coincides with a circumferential direction around rotation axis line A. Rotation detector <NUM> is provided at one end of rotary shaft <NUM> in the rotation axis line direction. A load (not illustrated) that is rotationally driven due to the rotation of rotary shaft <NUM> is attached to the other end of rotary shaft <NUM> in the rotation axis line direction. For example, rotary shaft <NUM> is made of a magnetic metal such as iron.

Case <NUM> is attached to main body <NUM> to cover one end of rotary shaft <NUM> in the rotation axis line direction and rotation detector <NUM>. For example, case <NUM> is made of a magnetic metal such as iron.

Rotation detector <NUM> detects the rotation of rotary shaft <NUM>. For example, rotation detector <NUM> detects a rotational position of rotary shaft <NUM>, a rotation direction of rotary shaft <NUM>, a rotation speed of rotary shaft <NUM>, and the like. For example, rotation detector <NUM> is an absolute encoder. As described above, rotation detector <NUM> is provided at one end of rotary shaft <NUM> in the rotation axis line direction. As illustrated in <FIG> and <FIG>, rotation detector <NUM> includes rotary plate <NUM>, substrate <NUM>, magnet <NUM>, a plurality of power generation elements <NUM>, <NUM>, a plurality of magnetic sensors <NUM>, <NUM>, optical sensor <NUM>, and control circuit <NUM>.

Rotary plate <NUM> extends in a direction orthogonal to the rotation axis line direction. Specifically, rotary plate <NUM> has a disk shape having a main surface extending in a direction orthogonal to the rotation axis line direction, and is circular when viewed from the rotation axis line direction. Rotary plate <NUM> is attached to one end of rotary shaft <NUM> in the rotation axis line direction. The axis of rotary plate <NUM> coincides with rotation axis line A. Rotary plate <NUM> rotates together with rotary shaft <NUM>.

Substrate <NUM> extends in a direction orthogonal to the rotation axis line direction. Specifically, substrate <NUM> has a disk shape having a main surface extending in a direction orthogonal to the rotation axis line direction, and is circular when viewed from the rotation axis line direction. Substrate <NUM> is disposed at an interval from one end of rotary shaft <NUM> and rotary plate <NUM> in the rotation axis line direction, and faces rotary plate <NUM>. The axis of substrate <NUM> coincides with rotation axis line A. Substrate <NUM> is fixed to an inner surface of case <NUM>, and does not rotate together with rotary shaft <NUM>.

Magnet <NUM> rotates together with rotary shaft <NUM>. Specifically, when rotary shaft <NUM> rotates, magnet <NUM> rotates together with rotary shaft <NUM> and rotary plate <NUM>. Magnet <NUM> has an annular shape and is disposed in the rotation direction of rotary shaft <NUM>. Magnet <NUM> has a plate shape of which a thickness direction is the rotation axis line direction. Magnet <NUM> is disposed on the main surface of rotary plate <NUM> on the side opposite to substrate <NUM>. Magnet <NUM> has an N pole and an S pole disposed side by side with the N pole in the rotation direction of rotary shaft <NUM>. One half of magnet <NUM> is magnetized to the N pole, and the other half of magnet <NUM> is magnetized to the S pole.

Each of the plurality of power generation elements <NUM>, <NUM> generates power according to a change in the magnetic field due to the rotation of magnet <NUM> together with rotary shaft <NUM>.

The plurality of power generation elements <NUM>, <NUM> are disposed with a phase difference in the rotation direction of rotary shaft <NUM>. Specifically, in the rotation direction of rotary shaft <NUM>, the plurality of power generation elements <NUM>, <NUM> are disposed with an angular interval larger than or equal to an angular interval between a first position where one power generation element of the plurality of power generation elements <NUM>, <NUM> generates power when rotary shaft <NUM> rotates clockwise and a second position closest to the first position among one or more positions where the one power generation element generates power when rotary shaft <NUM> rotates counterclockwise in the rotation direction of rotary shaft <NUM>. Note that the clockwise direction is a clockwise direction when viewed from the side of substrate <NUM> opposite to rotary plate <NUM> in the rotation axis line direction, and the counterclockwise direction is a counterclockwise direction when viewed from the side of substrate <NUM> opposite to rotary plate <NUM> in the rotation axis line direction. The same applies to the following description.

<FIG> is a diagram for describing an example of a determination operation of rotation detector <NUM> when rotary shaft <NUM> rotates clockwise. For example, position i illustrated in <FIG> is an example of the first position where one power generation element <NUM> out of the plurality of power generation elements <NUM>, <NUM> generates power when rotary shaft <NUM> rotates clockwise. Position viii illustrated in <FIG> is an example of the second position closest to position i among one or more positions vi and viii where one power generation element <NUM> generates power when rotary shaft <NUM> rotates counterclockwise. The angular interval between position i and position viii in the rotation direction of rotary shaft <NUM> is <NUM> degrees, and the plurality of power generation elements <NUM>, <NUM> are disposed with an angular interval of <NUM> degrees or more in the rotation direction of rotary shaft <NUM>. In this exemplary embodiment, the plurality of power generation elements <NUM>, <NUM> are disposed at an angular interval of <NUM> degrees in the rotation direction of rotary shaft <NUM>.

Note that, for example, the angular interval between power generation element <NUM> and power generation element <NUM> in the rotation direction of rotary shaft <NUM> is an angle formed by a center line extending in the radial direction (refer to arrow Y in <FIG>) around rotation axis line A and passing through the center of magnetism sensing portion <NUM> of power generation element <NUM> in the longitudinal direction and a center line extending in the radial direction around rotation axis line A and passing through the center of magnetism sensing portion <NUM> of power generation element <NUM> in the longitudinal direction.

Power generation element <NUM> extends in a tangential direction of the rotation direction of rotary shaft <NUM>, and is disposed on the main surface of substrate <NUM> on the side opposite to rotary shaft <NUM> (the side opposite to rotary plate <NUM>). Power generation element <NUM> includes magnetism sensing portion <NUM> and coil <NUM> wound around magnetism sensing portion <NUM>. Magnetism sensing portion <NUM> is a magnetic body extending in the tangential direction of the rotation direction of rotary shaft <NUM>, and is located on the side of substrate <NUM> opposite to rotary plate <NUM>. For example, magnetism sensing portion <NUM> is a magnetic body that exhibits a large Barkhausen effect, and is a Wiegand wire extending in the tangential direction of the rotation direction of rotary shaft <NUM>. A Wiegand wire is a magnetic body in which when a magnetic field of a predetermined value or more is applied in a longitudinal direction of the Wiegand wire, magnetization directions are aligned to be directed to one side in the longitudinal direction. When a direction of the magnetic flux flowing in the longitudinal direction of the Wiegand wire changes, the magnetization direction of the Wiegand wire is rapidly reversed and a voltage pulse is induced across a coil wound around the Wiegand wire. As described above, power generation element <NUM> generates power.

Power generation element <NUM> extends in the tangential direction of the rotation direction of rotary shaft <NUM>, and is disposed on the main surface of substrate <NUM> on the side opposite to rotary shaft <NUM> (the side opposite to rotary plate <NUM>). Power generation element <NUM> includes magnetism sensing portion <NUM> and coil <NUM> wound around magnetism sensing portion <NUM>. Magnetism sensing portion <NUM> is a magnetic body extending in the tangential direction of the rotation direction of rotary shaft <NUM>, and is located on the side of substrate <NUM> opposite to rotary plate <NUM>. For example, magnetism sensing portion <NUM> is a magnetic body that exhibits the large Barkhausen effect, and is a Wiegand wire extending in the tangential direction of the rotation direction of rotary shaft <NUM>. Power generation element <NUM> generates power in the same manner as power generation element <NUM>.

A plurality of magnetic sensors <NUM>, <NUM> are provided to correspond to the plurality of power generation elements <NUM>, <NUM>, respectively. Magnetic sensor <NUM> is provided corresponding to power generation element <NUM>, and operates based on the power generated by power generation element <NUM>. Magnetic sensor <NUM> is provided corresponding to power generation element <NUM>, and operates based on the power generated by power generation element <NUM>. The plurality of magnetic sensors <NUM>, <NUM> are disposed on the main surface of substrate <NUM> on rotary shaft <NUM> side (rotary plate <NUM> side).

The plurality of magnetic sensors <NUM>, <NUM> are disposed with a phase difference in the rotation direction of rotary shaft <NUM>. Specifically, each of the plurality of magnetic sensors <NUM>, <NUM> is disposed at the same position as the corresponding power generation element among the plurality of power generation elements <NUM>, <NUM> in the rotation direction of rotary shaft <NUM>.

Magnetic sensor <NUM> is disposed at the same position as power generation element <NUM> in the rotation direction of rotary shaft <NUM>. For example, magnetic sensor <NUM> is disposed such that the center of magnetic sensor <NUM> is located on a center line extending in the radial direction about rotation axis line A and passing through the center of magnetism sensing portion <NUM> of power generation element <NUM> in the longitudinal direction. Magnetic sensor <NUM> is disposed side by side with power generation element <NUM> and outside power generation element <NUM> in the radial direction around rotation axis line A.

Optical sensor <NUM> is an optical encoder that includes light emission and reception element <NUM> and reflection pattern <NUM> and detects a rotation amount of rotary shaft <NUM>.

Light emission and reception element <NUM> is disposed on the main surface of substrate <NUM> on the side of rotary plate <NUM> and operates based on power from an external power supply <NUM> (refer to the functional block diagram illustrated in <FIG>). Light emission and reception element <NUM> faces reflection pattern <NUM> in the rotation axis line direction and emits light toward reflection pattern <NUM>. Light emission and reception element <NUM> receives the light reflected by reflection pattern <NUM>. The light reflected by reflection pattern <NUM> changes according to a rotational position of rotary shaft <NUM>. Optical sensor <NUM> detects a rotation amount of rotary shaft <NUM> based on the light reflected by reflection pattern <NUM>. In the present exemplary embodiment, light emission and reception element <NUM> corresponds to a light emission element and a light reception element.

Reflection pattern <NUM> is disposed on the main surface of rotary plate <NUM> on substrate <NUM> side. Reflection pattern <NUM> is disposed in the rotation direction of rotary shaft <NUM> and has an annular shape. For example, reflection pattern <NUM> has a reflection region that easily reflects light and a non-reflection region that hardly reflects light. For example, the reflection region and the non-reflection region are alternately disposed in the rotation direction of rotary shaft <NUM>.

Control circuit <NUM> is disposed on the main surface of substrate <NUM> on rotary shaft <NUM> side (rotary plate <NUM> side), and is electrically connected to power generation element <NUM> and the like.

<FIG> is a block diagram illustrating a functional configuration of rotation detector <NUM> in <FIG>.

As illustrated in <FIG>, rotation detector <NUM> further includes generated power supply unit <NUM>, polarity determination unit <NUM>, magnetic pole determination unit <NUM>, signal processor <NUM>, information processor <NUM>, storage <NUM>, and communication unit <NUM>.

Generated power supply unit <NUM> supplies power generated by each of the plurality of power generation elements <NUM>, <NUM> to only a magnetic sensor corresponding to the power generation element among the plurality of magnetic sensors <NUM>, <NUM>. For example, generated power supply unit <NUM> supplies the power generated by power generation element <NUM> only to magnetic sensor <NUM> among the plurality of magnetic sensors <NUM>, <NUM>, and supplies the power generated by power generation element <NUM> to only magnetic sensor <NUM> among the plurality of magnetic sensors <NUM>, <NUM>.

Generated power supply unit <NUM> includes a plurality of full-wave rectifiers <NUM>, <NUM>, sensor power storage <NUM>, power storage <NUM>, a plurality of switches <NUM>, <NUM>, <NUM>, a plurality of internal power supplies <NUM>, <NUM>, a plurality of power supply monitoring units <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, a plurality of voltage adjusters <NUM>, <NUM>, a plurality of dischargers <NUM>, <NUM>, <NUM>, and a plurality of switches <NUM>,<NUM>.

Full-wave rectifier <NUM> is connected to power generation element <NUM> and rectifies the voltage pulse generated by power generation element <NUM>. Full-wave rectifier <NUM> is connected to power generation element <NUM> and rectifies a voltage pulse generated by power generation element <NUM>.

Sensor power storage <NUM> stores power generated from each of the plurality of power generation elements <NUM>, <NUM> and supplied to a magnetic sensor corresponding to the power generation element among the plurality of magnetic sensors <NUM>, <NUM>. In a case where power generation element <NUM> generates power, sensor power storage <NUM> stores the power generated from power generation element <NUM> and supplied to magnetic sensor <NUM>. In a case where power generation element <NUM> generates power, sensor power storage <NUM> stores the power generated from power generation element <NUM> and supplied to magnetic sensor <NUM>.

Power storage <NUM> stores power generated by each of the plurality of power generation elements <NUM>, <NUM> and supplied to constituent elements than the plurality of magnetic sensors <NUM>, <NUM>. Power storage <NUM> includes first storage <NUM> that stores power generated from power generation element <NUM> and supplied to a constituent element other than magnetic sensor <NUM>, and second storage <NUM> that stores power generated from power generation element <NUM> and supplied to a constituent element other than magnetic sensor <NUM>.

Switch <NUM> is an example of a disconnection unit capable of electrically disconnecting sensor power storage <NUM> and power storage <NUM>. When neither power generation element <NUM> or power generation element <NUM> generates power, switch <NUM> is brought into an OFF state in which power is cut off, and electrically disconnects sensor power storage <NUM> and power storage <NUM>. Switch <NUM> is brought into an ON state in which power can be transmitted in a period in which one of power generation element <NUM> and power generation element <NUM> is generating power. Switch <NUM> is brought into an OFF state in which power is cut off when power generation element <NUM> is not generating power, and is brought into an ON state in which power can be transmitted in a period in which power generation element <NUM> is generating power. Switch <NUM> is brought into an OFF state in which power is cut off when power generation element <NUM> is not generating power, and is brought into an ON state in which power can be transmitted in a period in which power generation element <NUM> is generating power.

Internal power supply <NUM> is a power supply that receives the supply of power stored in sensor power storage <NUM> and supplies the power to magnetic sensor <NUM> or magnetic sensor <NUM>. Internal power supply <NUM> is a power supply that receives the supply of power stored in power storage <NUM> and supplies the power to, for example, information processor <NUM> other than the plurality of magnetic sensors <NUM>, <NUM>.

Power supply monitoring unit <NUM> monitors power between sensor power storage <NUM> and voltage adjuster <NUM>. Power supply monitoring unit <NUM> monitors power between voltage adjuster <NUM> and internal power supply <NUM>. Power supply monitoring unit <NUM> monitors power between full-wave rectifier <NUM> and first storage <NUM>. Power supply monitoring unit <NUM> monitors power between full-wave rectifier <NUM> and second storage <NUM>. Power supply monitoring unit <NUM> monitors power between voltage adjuster <NUM> and internal power supply <NUM>.

Voltage adjuster <NUM> outputs a constant voltage with the ground potential as a reference potential and a voltage between terminals of a capacitor of sensor power storage <NUM> as an input voltage. The output voltage of voltage adjuster <NUM> is supplied to internal power supply <NUM>. Voltage adjuster <NUM> outputs a constant voltage with the ground potential as a reference potential and a voltage between terminals of a capacitor of first storage <NUM> or second storage <NUM> as an input voltage. The output voltage of voltage adjuster <NUM> is supplied to internal power supply <NUM>. For example, each of the plurality of voltage adjusters <NUM>, <NUM> is a low drop out (LDO) regulator.

Discharger <NUM> discharges the power stored in sensor power storage <NUM> when power generation element <NUM> and power generation element <NUM> are not generating power. Discharger <NUM> discharges the power stored in first storage <NUM> when power generation element <NUM> is not generating power. Discharger <NUM> discharges the power stored in second storage <NUM> when power generation element <NUM> is not generating power.

When power generation element <NUM> is not generating power, switch <NUM> is brought into an OFF state in which power from internal power supply <NUM> is cut off not to be supplied to magnetic sensor <NUM>, and into an ON state in which the power from internal power supply <NUM> can be transmitted to magnetic sensor <NUM> in a period in which power generation element <NUM> generates power. When power generation element <NUM> is not generating power, switch <NUM> is brought into an OFF state in which power from internal power supply <NUM> is cut off not to be supplied to magnetic sensor <NUM>, and into an ON state in which the power from internal power supply <NUM> can be transmitted to magnetic sensor <NUM> in a period in which power generation element <NUM> is generating power.

Polarity determination unit <NUM> determines a polarity of the power generated by each of the plurality of power generation elements <NUM>, <NUM>. Polarity determination unit <NUM> includes first determination portion <NUM> that determines a polarity of the power generated by power generation element <NUM> and second determination portion <NUM> that determines a polarity of the power generated by power generation element <NUM>.

Magnetic pole determination unit <NUM> determines a magnetic pole detected by each of the plurality of magnetic sensors <NUM>, <NUM>. Magnetic pole determination unit <NUM> includes first determination portion <NUM> that determines a magnetic pole detected by magnetic sensor <NUM> and second determination portion <NUM> that determines a magnetic pole detected by magnetic sensor <NUM>.

Signal processor <NUM> is driven based on power from external power supply <NUM>, and transmits a detection result from optical sensor <NUM> to information processor <NUM>.

Information processor <NUM> determines a rotational position of rotary shaft <NUM> by using the plurality of magnetic sensors <NUM>, <NUM>. The determination of a rotational position of rotary shaft <NUM> using information processor <NUM> will be described later.

Storage <NUM> stores a rotational position, a rotation direction, and the like of rotary shaft <NUM>. For example, storage <NUM> is configured by a non-volatile memory such as an FRAM (registered trademark).

Communication unit <NUM> connects information processor <NUM> and signal processor <NUM> to be capable of performing wired communication or wireless communication.

<FIG> is a diagram for describing an example of a determination operation of rotation detector <NUM> in <FIG> when rotary shaft <NUM> rotates clockwise. Part (a) of <FIG> illustrates a state in which reference position B is located at position i, part (b) of <FIG> illustrates a state in which reference position B is located at position ii, part (c) of <FIG> illustrates a state in which reference position B is located at position iii, and part (d) of <FIG> illustrates a state in which reference position B is located at position iv.

<FIG> is a diagram for describing an example of a determination operation of rotation detector <NUM> in <FIG> when rotary shaft <NUM> rotates counterclockwise. Part (a) of <FIG> illustrates a state in which reference position B is located at position v, part (b) of <FIG> illustrates a state in which reference position B is located at position vi, part (c) of <FIG> illustrates a state in which reference position B is located at position vii, and part (d) of <FIG> illustrates a state in which reference position B is located at position viii.

Reference position B is a reference position in the rotation direction of rotary shaft <NUM>, and in the present exemplary embodiment, the center of the N pole in the rotation direction of rotary shaft <NUM> is set as a reference position.

First, a case where rotary shaft <NUM> rotates clockwise will be described with reference to <FIG>. In this case, when reference position B is located at position i, position ii, position iii, and position iv, one of power generation element <NUM> and power generation element <NUM> generates power.

For example, in a case where rotary shaft <NUM> rotates clockwise and reference position B is located at position i as illustrated in (a) of <FIG>, the direction of the magnetic field in the longitudinal direction of power generation element <NUM> is reversed by the magnetic field of magnet <NUM>, and power generation element <NUM> generates power. On the other hand, in a case where reference position B is located at position i, the direction of the magnetic field in the longitudinal direction of power generation element <NUM> is not reversed by the magnetic field of magnet <NUM>, and power generation element <NUM> does not generate power.

When power generation element <NUM> generates power, magnetic sensor <NUM> operates based on the power from power generation element <NUM>. When reference position B is located at position i, magnetic sensor <NUM> faces the S pole. Therefore, when reference position B is located at position i, magnetic sensor <NUM> outputs a signal indicating that reference position B faces the S pole.

When rotary shaft <NUM> further rotates clockwise and reference position B is located at position ii as illustrated in part (b) of <FIG>, the direction of the magnetic field in the longitudinal direction of power generation element <NUM> is reversed by the magnetic field of magnet <NUM>, and power generation element <NUM> generates power. On the other hand, when reference position B is located at position ii, the direction of the magnetic field in the longitudinal direction of power generation element <NUM> is not reversed by the magnetic field of magnet <NUM>, and power generation element <NUM> does not generate power.

When power generation element <NUM> generates power, magnetic sensor <NUM> operates based on the power from power generation element <NUM>. When reference position B is located at position ii, magnetic sensor <NUM> faces the S pole. Therefore, when reference position B is located at position ii, magnetic sensor <NUM> outputs a signal indicating that reference position B faces the S pole.

When rotary shaft <NUM> further rotates clockwise and reference position B is located at position iii as illustrated in part (c) of <FIG>, the direction of the magnetic field in the longitudinal direction of power generation element <NUM> is reversed by the magnetic field of magnet <NUM>, and power generation element <NUM> generates power. On the other hand, when reference position B is located at position iii, the direction of the magnetic field in the longitudinal direction of power generation element <NUM> is not reversed by the magnetic field of magnet <NUM>, and power generation element <NUM> does not generate power.

When power generation element <NUM> generates power, magnetic sensor <NUM> operates based on the power from power generation element <NUM>. When reference position B is located at position iii, magnetic sensor <NUM> faces the N pole. Therefore, when reference position B is located at position iii, magnetic sensor <NUM> outputs a signal indicating that reference position B faces the N pole.

In a case where rotary shaft <NUM> further rotates counterclockwise and reference position B is located at position iv as illustrated in (d) of <FIG>, the direction of the magnetic field in the longitudinal direction of power generation element <NUM> is reversed by the magnetic field of magnet <NUM>, and power generation element <NUM> generates power. On the other hand, in a case where reference position B is located at position iv, the direction of the magnetic field in the longitudinal direction of power generation element <NUM> is not reversed by the magnetic field of magnet <NUM>, and power generation element <NUM> does not generate power.

When power generation element <NUM> generates power, magnetic sensor <NUM> operates based on the power from power generation element <NUM>. When reference position B is located at position iv, magnetic sensor <NUM> faces the N pole. Therefore, when reference position B is located at position iv, magnetic sensor <NUM> outputs a signal indicating that reference position B faces the N pole.

Next, a case where rotary shaft <NUM> rotates counterclockwise will be described with reference to <FIG>. In this case, when reference position B is located at position v, position vi, position vii, and position viii, one of power generation element <NUM> and power generation element <NUM> generates power.

For example, when rotary shaft <NUM> rotates counterclockwise and reference position B is located at position v as illustrated in (a) of <FIG>, the direction of the magnetic field in the longitudinal direction of power generation element <NUM> is reversed by the magnetic field of magnet <NUM>, and power generation element <NUM> generates power. On the other hand, in a case where reference position B is located at position v, the direction of the magnetic field in the longitudinal direction of power generation element <NUM> is not reversed by the magnetic field of magnet <NUM>, and power generation element <NUM> does not generate power.

When power generation element <NUM> generates power, magnetic sensor <NUM> operates based on the power from power generation element <NUM>. When reference position B is located at position v, magnetic sensor <NUM> faces the N pole. Therefore, when reference position B is located at position v, magnetic sensor <NUM> outputs a signal indicating that the reference position faces the N pole.

In a case where rotary shaft <NUM> further rotates counterclockwise and reference position B is located at position vi as illustrated in part (b) of <FIG>, the direction of the magnetic field in the longitudinal direction of power generation element <NUM> is reversed by the magnetic field of magnet <NUM>, and power generation element <NUM> generates power. On the other hand, when reference position B is located at position vi, the direction of the magnetic field in the longitudinal direction of power generation element <NUM> is not reversed by the magnetic field of magnet <NUM>, and power generation element <NUM> does not generate power.

When power generation element <NUM> generates power, magnetic sensor <NUM> operates based on the power from power generation element <NUM>. When reference position B is located at position vi, magnetic sensor <NUM> faces the N pole. Therefore, when reference position B is located at position vi, magnetic sensor <NUM> outputs a signal indicating that the magnetic sensor faces the N pole.

In a case where rotary shaft <NUM> further rotates counterclockwise and reference position B is located at position vii as illustrated in part (c) of <FIG>, the direction of the magnetic field in the longitudinal direction of power generation element <NUM> is reversed by the magnetic field of magnet <NUM>, and power generation element <NUM> generates power. On the other hand, when reference position B is located at position vii, the direction of the magnetic field in the longitudinal direction of power generation element <NUM> is not reversed by the magnetic field of magnet <NUM>, and power generation element <NUM> does not generate power.

When power generation element <NUM> generates power, magnetic sensor <NUM> operates based on the power from power generation element <NUM>. When reference position B is located at position vii, magnetic sensor <NUM> faces the S pole. Therefore, when reference position B is located at position vii, magnetic sensor <NUM> outputs a signal indicating that magnetic sensor B faces the S pole.

In a case where rotary shaft <NUM> further rotates counterclockwise and reference position B is located at position viii as illustrated in part (d) of <FIG>, the direction of the magnetic field in the longitudinal direction of power generation element <NUM> is reversed by the magnetic field of magnet <NUM>, and power generation element <NUM> generates power. On the other hand, when reference position B is located at position viii, the direction of the magnetic field in the longitudinal direction of power generation element <NUM> is not reversed by the magnetic field of magnet <NUM>, and power generation element <NUM> does not generate power.

When power generation element <NUM> generates power, magnetic sensor <NUM> operates based on the power from power generation element <NUM>. When reference position B is located at position viii, magnetic sensor <NUM> faces the S pole. Therefore, when reference position B is located at position viii, magnetic sensor <NUM> outputs a signal indicating that magnetic sensor B faces the S pole.

For example, information processor <NUM> determines a rotational position of rotary shaft <NUM> by determining in which region among the plurality of regions I to IV arranged in the rotation direction of rotary shaft <NUM> reference position B in the rotation direction of rotary shaft <NUM> is located based on power generation information indicating a power generation element that has generated power among the plurality of power generation elements <NUM>, <NUM> and detection information indicating a detection result from the magnetic sensor corresponding to the power generation element among the plurality of magnetic sensors <NUM>, <NUM>. Storage <NUM> stores a region in which reference position B is determined to be located by information processor <NUM> among the plurality of regions I to IV.

For example, the power generation information is <NUM>-bit information indicating <NUM> in a case where power generation element <NUM> has generated power and indicating <NUM> in a case where power generation element <NUM> has generated power. For example, the detection information is <NUM>-bit information indicating <NUM> in a case where magnetic sensor <NUM> has detected the S pole and magnetic sensor <NUM> has detected the S pole, and indicating <NUM> in a case where magnetic sensor <NUM> has detected the N pole and magnetic sensor <NUM> has detected the N pole.

For example, each of the plurality of regions I to IV is a region that extends in the radial direction about rotation axis line A and is sandwiched between two adjacent straight lines among a plurality of straight lines arranged at equal intervals in the rotation direction of rotary shaft <NUM>. In the present exemplary embodiment, a region including position i and position viii is set as region I, a region including position ii and position vii is set as region II, a region including position iii and position vi is set as region III, and a region including position iv and position v is set as region IV.

As described above, in a case where reference position B is located at position i, power generation element <NUM> generates power, and magnetic sensor <NUM> detects the S pole. In a case where reference position B is located at position viii, power generation element <NUM> generates power, and magnetic sensor <NUM> detects the S pole. That is, in these cases, (detection information, power generation information) = (<NUM>, <NUM>). Therefore, in a case of (detection information, power generation information) = (<NUM>, <NUM>), information processor <NUM> determines that reference position B is located at position i or in the vicinity of position viii, and reference position B is located in region I.

In a case where reference position B is located at position ii, power generation element <NUM> generates power, and magnetic sensor <NUM> detects the S pole. In a case where reference position B is located at position vii, power generation element <NUM> generates power, and magnetic sensor <NUM> detects the S pole. That is, in these cases, (detection information, power generation information) = (<NUM>, <NUM>). Therefore, in a case of (detection information, power generation information) = (<NUM>, <NUM>), information processor <NUM> determines that reference position B is located at position ii or in the vicinity of position vii, and reference position B is located in region II.

When reference position B is located at position iii, power generation element <NUM> generates power, and magnetic sensor <NUM> detects the N pole. When reference position B is located at position vi, power generation element <NUM> generates power, and magnetic sensor <NUM> detects the N pole. That is, in these cases, (detection information, power generation information) = (<NUM>, <NUM>). Therefore, in a case of (detection information, power generation information) = (<NUM>, <NUM>), information processor <NUM> determines that reference position B is located at position iii or in the vicinity of position vi, and reference position B is located in region III.

In a case where reference position B is located at position iv, power generation element <NUM> generates power, and magnetic sensor <NUM> detects the N pole. In a case where reference position B is located at position v, power generation element <NUM> generates power, and magnetic sensor <NUM> detects the N pole. That is, in these cases, (detection information, power generation information) = (<NUM>, <NUM>). Therefore, in a case of (detection information, power generation information) = (<NUM>, <NUM>), information processor <NUM> determines that reference position B is located at position iv or in the vicinity of position v, and reference position B is located in region IV.

In a case where a region in which current reference position B is determined to be located is not a region adjacent to a region in which previous reference position B is determined to be located among the plurality of regions I to IV, information processor <NUM> stores the occurrence of an error in storage <NUM>.

For example, information processor <NUM> determines a rotational position of rotary shaft <NUM> every time one of power generation element <NUM> and power generation element <NUM> generates power and stores the determined rotational position in storage <NUM>, and in a case where a region in which current reference position B is determined to be located is region I and a region in which previous reference position B is determined to be located is region III, information processor <NUM> stores the occurrence of an error in storage <NUM>.

In a case where a region in which current reference position B is determined to be located is not a region adjacent to a region in which previous reference position B is determined to be located among the plurality of regions I to IV, information processor <NUM> stores, in storage <NUM>, that a transition has occurred from the region in which previous reference position B is determined to be located to the region in which current reference position B is determined to be located.

For example, in a case where a region in which current reference position B is determined to be located is region I and a region in which previous reference position B is determined to be located is region III, information processor <NUM> stores that a transition from region III to region I has occurred in storage <NUM>.

Information processor <NUM> determines a rotation direction of rotary shaft <NUM> based on the power generation information, the detection information, and polarity information indicating the polarity determined by polarity determination unit <NUM>.

For example, the polarity information is <NUM>-bit information indicating <NUM> in a case where the polarity of the power generated by power generation element <NUM> is negative, and indicating <NUM> in a case where the polarity of the power generated by power generation element <NUM> is positive. In other words, for example, the polarity information is <NUM>-bit information indicating <NUM> in a case where the polarity of the power generated by power generation element <NUM> is negative, and indicating <NUM> in a case where the polarity of the power generated by power generation element <NUM> is positive.

For example, the polarity of the power generated by power generation element <NUM> in a case where reference position B is located at position i and the polarity of the power generated by power generation element <NUM> in a case where reference position B is located at position viii are reversed. For example, when the polarity of the power generated by power generation element <NUM> in a case where reference position B is located at position i is positive, and the polarity of the power generated by power generation element <NUM> in a case where reference position B is located at position viii is negative, information processor <NUM> can determine that rotary shaft <NUM> rotates clockwise in a case where the polarity information is <NUM>, and can determine that rotary shaft <NUM> rotates counterclockwise in a case where the polarity information is <NUM>.

In a case where the region in which current reference position B is determined to be located among the plurality of regions I to IV is adjacent to the region in which previous reference position B is determined to be located, and the transition from the polarity determined by the previous polarity determination unit <NUM> to the polarity determined by the current polarity determination unit <NUM> is not normal, information processor <NUM> stores the occurrence of an error in storage <NUM>.

Table <NUM> is a table illustrating a relationship between power generation positions of the plurality of power generation elements <NUM>, <NUM> of rotation detector <NUM> in <FIG>, a rotation direction of rotary shaft <NUM>, and the like. As illustrated in Table <NUM>, for example, the polarity information indicates <NUM> in a case where reference position B is located at position i, indicates <NUM> in a case where reference position B is located at position ii, indicates <NUM> in a case where reference position B is located at position iii, and indicates <NUM> in a case where reference position B is located at position iv. For example, the polarity information indicates <NUM> in a case where reference position B is located at position v, indicates <NUM> in a case where reference position B is located at position vi, indicates <NUM> in a case where reference position B is located at position vii, and indicates <NUM> in a case where reference position B is located at position viii.

For example, in a case where a region in which current reference position B is determined to be located is region I, and a region in which previous reference position B is determined to be located is region II, when the polarity information has transitioned from <NUM> to <NUM>, information processor <NUM> can ascertain that rotary shaft <NUM> has rotated counterclockwise and reference position B has moved from region II to region I, and can determine that the detection of the rotational position of rotary shaft <NUM> is normal. On the other hand, in a case where a region in which current reference position B is determined to be located is region I and a region in which previous reference position B is determined to be located is region II, when the polarity information has transitioned from <NUM> to <NUM>, information processor <NUM> can ascertain that rotary shaft <NUM> has rotated clockwise and reference position B has moved from region II to region I, cannot determine that reference position B is located in region III and region IV, and can determine that the detection of the rotational position of rotary shaft <NUM> is abnormal. Therefore, in a case where a region in which current reference position B is determined to be located is region I and a region in which previous reference position B is determined to be located is region II, when the polarity information has transitioned from <NUM> to <NUM>, information processor <NUM> determines that the transition from the previous polarity determined by polarity determination unit <NUM> to the current polarity determined by polarity determination unit <NUM> is not normal and stores the occurrence of an error in storage <NUM>.

In a case where optical sensor <NUM> switches from a non-power-supply state in which power is not supplied from power supply <NUM> to a power-supply state in which power is supplied from power supply <NUM>, information processor <NUM> determines a rotational position of rotary shaft <NUM> based on a rotational position of rotary shaft <NUM> determined by using the plurality of magnetic sensors <NUM>, <NUM> in the non-power-supply state and a rotation amount of rotary shaft <NUM> detected by optical sensor <NUM> after the optical sensor switches to the power-supply state.

For example, information processor <NUM> determines the rotational position of rotary shaft <NUM> by adding the rotation amount of rotary shaft <NUM> detected by optical sensor <NUM> after the optical sensor switches to the power-supply state to the rotational position of rotary shaft <NUM> determined by using the plurality of magnetic sensors <NUM>, <NUM> immediately before optical sensor <NUM> switches from the non-power-supply state to the power-supply state.

Information processor <NUM> updates a count value for calculating a rotation speed of rotary shaft <NUM> based on the region in which current reference position B is determined to be located among the plurality of regions I to IV, the current polarity determined by polarity determination unit <NUM>, the region in which previous reference position B is determined to be located among the plurality of regions I to IV, and the previous polarity determined by polarity determination unit <NUM>.

Table <NUM> is a table for describing an example of a count value update operation of rotation detector <NUM> in <FIG>.

As illustrated in Table <NUM>, for example, in a case where the previous polarity information indicates <NUM>, the previous detection information indicates <NUM>, the previous power generation information indicates <NUM>, the current polarity information indicates <NUM>, the current detection information indicates <NUM>, and the current power generation information indicates <NUM>, it is ascertained that rotary shaft <NUM> has rotated clockwise and reference position B has moved from region IV to region I, and information processor <NUM> decrements the count value by <NUM>.

For example, in a case where the previous polarity information indicates <NUM>, the previous detection information indicates <NUM>, the previous power generation information indicates <NUM>, the current polarity information indicates <NUM>, the current detection information indicates <NUM>, and the current power generation information indicates <NUM>, it is ascertained that rotary shaft <NUM> has rotated clockwise and reference position B has moved from region IV to region I, and information processor <NUM> decrements the count value by <NUM>.

For example, in a case where the previous polarity information indicates <NUM>, the previous detection information indicates <NUM>, the previous power generation information indicates <NUM>, the current polarity information indicates <NUM>, the current detection information indicates <NUM>, and the current power generation information indicates <NUM>, it is ascertained that rotary shaft <NUM> has rotated counterclockwise and reference position B has moved from region I to region IV, and information processor <NUM> increments the count value by <NUM>.

As described above, information processor <NUM> can calculate the rotation speed of rotary shaft <NUM> by updating the count value.

Rotation detector <NUM> according to the first exemplary embodiment has been described above.

Rotation detector <NUM> according to the present exemplary embodiment includes magnet <NUM> that rotates together with rotary shaft <NUM>, a plurality of power generation elements <NUM>, <NUM> that generate power according to a change in a magnetic field due to the rotation of magnet <NUM> together with rotary shaft <NUM>, and a plurality of magnetic sensors <NUM>, <NUM> each provided to a corresponding one of the plurality of power generation elements <NUM>, <NUM>. Rotation detector <NUM> according to the present exemplary embodiment further includes information processor <NUM> that determines a rotational position of rotary shaft <NUM> by using the plurality of magnetic sensors <NUM>, <NUM>, and generated power supply unit <NUM> that supplies power generated by each of the plurality of power generation elements <NUM>, <NUM> only to the corresponding one of the plurality of power generation elements <NUM>,<NUM>.

According to this, since the power generated by the plurality of power generation elements <NUM>, <NUM> can be supplied to only a magnetic sensor corresponding to the power generation element among the plurality of magnetic sensors <NUM>, <NUM>, consumption of the power generated by each of the plurality of power generation elements <NUM>, <NUM> can be suppressed, and the magnetic sensor corresponding to the power generation element can be driven more reliably by using the power. Therefore, it is possible to suppress the occurrence of erroneous detection due to the magnetic sensor corresponding to the power generation element not being driven.

In rotation detector <NUM> according to the present exemplary embodiment, information processor <NUM> determines the rotational position of rotary shaft <NUM>, and the rotation detector <NUM> further includes storage <NUM> that stores a region in which reference position B is determined to be located by information processor <NUM> among the plurality of regions I to IV. The determination of rotary shaft <NUM> is performed by determining in which region among the plurality of regions I to IV arranged in the rotation direction of rotary shaft <NUM> reference position B in the rotation direction of rotary shaft <NUM> is located, based on the power generation information indicating a power generation element that has generated power among the plurality of power generation elements <NUM>, <NUM> and the detection information indicating a detection result from a magnetic sensor corresponding to the power generation element among the plurality of magnetic sensors <NUM>, <NUM>.

According to this, since a rotational position of rotary shaft <NUM> can be determined by using the power generation information and the detection information without using the polarity of the power generated by each of the plurality of power generation elements <NUM>, <NUM>, even in a case where the power generated by each of the plurality of power generation elements <NUM>, <NUM> is small and the polarity of the power cannot be determined, a rotational position of rotary shaft <NUM> can be determined, and the occurrence of erroneous detection can be suppressed.

In rotation detector <NUM> according to the present exemplary embodiment, in a case where a region in which current reference position B is determined to be located among the plurality of regions I to IV is not a region adjacent to a region in which previous reference position B is determined to be located, information processor <NUM> stores the occurrence of an error in storage <NUM>.

According to this, in a case where the region in which current reference position B is determined to be located is not a region adjacent to the region in which previous reference position B is determined to be located due to the plurality of magnetic sensors <NUM>, <NUM> not being driven, and erroneous detection occurs, the occurrence of erroneous detection can be stored, so that the occurrence of erroneous detection can be easily recognized.

In rotation detector <NUM> according to the present exemplary embodiment, in a case where the region in which current reference position B is determined to be located is not a region adjacent to the region in which previous reference position B is determined to be located among the plurality of regions I to IV, information processor <NUM> stores, in storage <NUM>, that a transition has occurred from the region in which previous reference position B is determined to be located to the region in which current reference position B is determined to be located.

According to this, since it is possible to easily recognize that erroneous detection has occurred in a case where reference position B transitions from a certain region to another region, it is possible to easily specify a cause of the erroneous detection.

Rotation detector <NUM> according to the present exemplary embodiment further includes polarity determination unit <NUM> that determines a polarity of the power generated by each of the plurality of power generation elements <NUM>, <NUM>, and information processor <NUM> determines a rotation direction of rotary shaft <NUM> based on the power generation information, the detection information, and the polarity information indicating the polarity determined by polarity determination unit <NUM>.

Accordingly, the occurrence of erroneous detection can be easily recognized by determining the rotation direction of rotary shaft <NUM> in addition to the rotational position of rotary shaft <NUM>.

In rotation detector <NUM> according to the present exemplary embodiment, in a case where the region in which current reference position B is determined to be located among the plurality of regions I to IV is a region adjacent to the region in which previous reference position B is determined to be located, when a transition from the previous polarity determined by polarity determination unit <NUM> to the current polarity determined by polarity determination unit <NUM> is not normal, information processor <NUM> stores the occurrence of an error in storage <NUM>.

According to this, when erroneous detection occurs due to, for example, the plurality of magnetic sensors <NUM>, <NUM> not being driven, error information indicating that erroneous detection has occurred can be stored, so that occurrence of erroneous detection can be easily recognized.

In rotation detector <NUM> according to the present exemplary embodiment, information processor <NUM> updates a count value for calculating a rotation speed of rotary shaft <NUM> based on the region in which current reference position B is determined to be located among the plurality of regions I to IV, the current polarity determined by polarity determination unit <NUM>, the region in which previous reference position B is determined to be located among the plurality of regions I to IV, and the previous polarity determined by polarity determination unit <NUM>.

According to this, since a count value for calculating the rotation speed of rotary shaft <NUM> can be more accurately updated, the occurrence of erroneous detection can be suppressed.

Rotation detector <NUM> according to the present exemplary embodiment further includes optical sensor <NUM> that includes light emission and reception element <NUM> that operates based on power from power supply <NUM> and detects a rotation amount of rotary shaft <NUM>. In a case where optical sensor <NUM> switches from the non-power-supply state in which power is not supplied from power supply <NUM> to the power-supply state in which power is supplied from power supply <NUM>, information processor <NUM> determines a rotational position of rotary shaft <NUM> based on a rotational position of rotary shaft <NUM> determined by using the plurality of magnetic sensors <NUM>, <NUM> in the non-power-supply state and a rotation amount of rotary shaft <NUM> detected by optical sensor <NUM> after the optical sensor switches to the power-supply state.

Accordingly, in the non-power-supply state, a rotational position of rotary shaft <NUM> can be determined by using the plurality of magnetic sensors <NUM>, <NUM>. When the optical sensor switches from the non-power-supply state to the power-supply state, a rotational position of rotary shaft <NUM> can be determined by adding the rotation amount of rotary shaft <NUM> detected by optical sensor <NUM> after the optical sensor switches to the power-supply state to the rotational position of rotary shaft <NUM> determined by using the plurality of magnetic sensors <NUM>, <NUM> in the non-power-supply state, so that the occurrence of erroneous detection can be further suppressed.

In rotation detector <NUM> according to the present exemplary embodiment, generated power supply unit <NUM> includes sensor power storage <NUM>, power storage <NUM>, and switch <NUM>. Sensor power storage <NUM> stores power generated from each of the plurality of power generation elements <NUM>, <NUM> and supplied to a magnetic sensor corresponding to the power generation element among the plurality of magnetic sensors <NUM>, <NUM>. Power storage <NUM> stores power generated by each of the plurality of power generation elements <NUM>, <NUM> and supplied to constituent elements than the plurality of magnetic sensors <NUM>, <NUM>. Switch <NUM> enables sensor power storage <NUM> and power storage <NUM> to be electrically disconnected.

According to this, since power generated from each of the plurality of power generation elements <NUM>, <NUM> can be reliably supplied by using a corresponding magnetic sensor among the plurality of magnetic sensors <NUM>, <NUM>, the occurrence of erroneous detection due to the magnetic sensor not being driven can be further suppressed.

In rotation detector <NUM> according to the present exemplary embodiment, the plurality of power generation elements <NUM>, <NUM> are disposed with an angular interval larger than or equal to an angular interval between a first position where one power generation element among the plurality of power generation elements <NUM>, <NUM> generates power when the rotary shaft <NUM> rotates clockwise and a second position closest to the first position among one or more positions where the one power generation element generates power when rotary shaft <NUM> rotates counterclockwise in the rotation direction of rotary shaft <NUM>. Each of the plurality of magnetic sensors <NUM>, <NUM> is disposed at the same position as a corresponding power generation element among the plurality of power generation elements <NUM>, <NUM> in the rotation direction of rotary shaft <NUM>.

According to this, since a magnetic pole detected by magnetic sensor <NUM> when power generation element <NUM> generates power at a certain position and a magnetic pole detected by magnetic sensor <NUM> when power generation element <NUM> generates power at another position can be easily made different from each other, a rotational position of rotary shaft <NUM> can be easily determined, and the occurrence of erroneous detection can be suppressed.

<FIG> is a diagram illustrating rotation detector 14a according to a second exemplary embodiment.

As illustrated in <FIG>, rotation detector 14a is mainly different from rotation detector <NUM> in further including power generation element <NUM> and magnetic sensor <NUM>.

Since power generation element <NUM> has the same configuration as power generation element <NUM> and power generation element <NUM>, a detailed description of power generation element <NUM> will be omitted. A plurality of power generation elements <NUM>, <NUM>, <NUM> are disposed at equal intervals in the rotation direction of rotary shaft <NUM>.

Since magnetic sensor <NUM> has the same configuration as magnetic sensor <NUM> and magnetic sensor <NUM>, a detailed description of magnetic sensor <NUM> will be omitted. Magnetic sensor <NUM> is disposed at the same position as power generation element <NUM> in the rotation direction of rotary shaft <NUM>, and is disposed outside power generation element <NUM> side by side with power generation element <NUM> in the radial direction of rotary shaft <NUM>.

As described above, by further providing power generation element <NUM> and magnetic sensor <NUM> corresponding to power generation element <NUM>, it is possible to cause any one of the plurality of power generation elements <NUM>, <NUM>, <NUM> to generate power at positions i to vi in a case where rotary shaft <NUM> rotates clockwise, and it is possible to cause any one of the plurality of power generation elements <NUM>, <NUM>, <NUM> to generate power at positions vii to xii when rotary shaft <NUM> rotates counterclockwise. As a result, it is possible to determine in which of six regions I to VI reference position B is located, and to more finely detect a position of rotary shaft <NUM> than rotation detector <NUM>.

<FIG> is a block diagram illustrating a part of a functional configuration of rotation detector 14a in <FIG>. <FIG> is a block diagram illustrating another part of the functional configuration of rotation detector 14a in <FIG>.

As illustrated in <FIG> and <FIG>, rotation detector 14a is mainly different from rotation detector <NUM> in including generated power supply unit 46a different from generated power supply unit <NUM>, including polarity determination unit 47a different from polarity determination unit <NUM>, and including magnetic pole determination unit 51a different from the magnetic pole determination unit <NUM>.

Generated power supply unit 46a is mainly different from generated power supply unit <NUM> in including full-wave rectifier <NUM>, third storage <NUM>, switch <NUM>, power supply monitoring unit <NUM>, discharger <NUM>, and switch <NUM>.

Generated power supply unit 46a can supply power generated by power generation element <NUM> to only magnetic sensor <NUM> corresponding to power generation element <NUM> among the plurality of magnetic sensors <NUM>, <NUM>, <NUM>.

Polarity determination unit 47a is mainly different from polarity determination unit <NUM> in further including third determination unit <NUM> that determines a polarity of power generated by power generation element <NUM>. A polarity of power generated from power generation element <NUM> can be determined by third determination unit <NUM>.

Magnetic pole determination unit 51a is mainly different from magnetic pole determination unit <NUM> in further including third determination unit <NUM> that determines a magnetic pole detected by magnetic sensor <NUM>. A magnetic pole detected by magnetic sensor <NUM> can be determined by third determination unit <NUM>.

As described above, the exemplary embodiments have been described as examples of the techniques disclosed in the present application. However, the technique according to the present disclosure is not limited thereto, and can also be applied to exemplary embodiments or modifications in which changes, replacements, additions, omissions, and the like are made as appropriate without departing from the concept of the present disclosure.

In the above-described exemplary embodiments, the case where magnet <NUM> has an annular shape has been described, but the present invention is not limited thereto. For example, the magnet need not to have an annular shape, and may have a disk shape, a rod shape, or the like.

In the above-described exemplary embodiment, the case where optical sensor <NUM> includes reflection pattern <NUM> has been described, but the present invention is not limited thereto. For example, the optical sensor may have a transmission pattern through which light is transmitted, and may detect a rotational position of the rotary shaft by receiving the light transmitted through the transmission pattern.

In the above-described exemplary embodiments, the case where each of the plurality of magnetic sensors <NUM>, <NUM> is disposed at the same position as a corresponding power generation element among the plurality of power generation elements <NUM>, <NUM> in the rotation direction of rotary shaft <NUM> has been described, but the present invention is not limited thereto. For example, each of the plurality of magnetic sensors may be disposed at a position shifted by <NUM> degrees from a corresponding power generation element among the plurality of power generation elements in the rotation direction of the rotary shaft.

In the above exemplary embodiments, the case where magnetic sensors <NUM>, <NUM> are disposed side by side with power generation elements <NUM>, <NUM> and outside power generation elements <NUM>, <NUM> in the radial direction about rotation axis line A has been described. However, magnetic sensors <NUM>, <NUM> are not necessarily required to be disposed outside power generation elements <NUM>, <NUM>, and may be disposed inside power generation elements <NUM>, <NUM>. Here, magnetic sensors <NUM>, <NUM> are required to accurately read the magnetic poles of magnet <NUM>. Therefore, in order to detect a magnetic flux of magnet <NUM>, magnetic sensors <NUM>, <NUM> are preferably disposed at positions where an S/N ratio is large. Therefore, when magnetic sensors <NUM>, <NUM> are viewed along rotation axis line A, magnetic sensors <NUM>, <NUM> are disposed at positions not overlapping power generation elements <NUM>, <NUM>. As a result, there is an advantage that magnetic sensors <NUM>, <NUM> are not easily affected by a change in the magnetic flux due to power generation of power generation elements <NUM>, <NUM>. In a case where magnetic sensors <NUM>, <NUM> are disposed outside power generation elements <NUM>, <NUM>, magnetic sensors <NUM>, <NUM> can be disposed even in a case of a substrate having a hole in the center, so that a central portion of rotation detector <NUM> can be easily made hollow.

In the above-described exemplary embodiments, the case where the plurality of power generation elements <NUM>, <NUM> are disposed on the main surface of substrate <NUM> on the side opposite to rotary plate <NUM> has been described, but the present invention is not limited thereto. For example, the plurality of power generation elements may be disposed on the main surface of the substrate on the rotary plate side.

In the above-described exemplary embodiments, the case where the plurality of magnetic sensors <NUM>, <NUM> are disposed on the main surface of substrate <NUM> on rotary plate <NUM> side has been described, but the present invention is not limited thereto. For example, the plurality of magnetic sensors may be disposed on the main surface of the substrate on the side opposite to the rotary plate.

In the above-described exemplary embodiment, the case where magnet <NUM> is disposed on the main surface of rotary plate <NUM> on the side opposite to substrate <NUM> has been described, but the present invention is not limited thereto. For example, the magnet may be disposed on the main surface of the rotary plate on the substrate side.

Claim 1:
A rotation detector (<NUM>) comprising:
a magnet (<NUM>) configured to rotate together with a rotary shaft (<NUM>);
a plurality of power generation elements (<NUM>, <NUM>) configured to generate power according to a change in a magnetic field due to rotation of the magnet (<NUM>) together with the rotary shaft (<NUM>);
a plurality of magnetic sensors (<NUM>, <NUM>) each provided to a corresponding one of the plurality of power generation elements (<NUM>, <NUM>), whereby each of the plurality of magnetic sensors (<NUM>, <NUM>) is disposed at the same position as the corresponding one of the plurality of power generation elements (<NUM>, <NUM>);
an information processor (<NUM>) configured to determine a rotational position of the rotary shaft (<NUM>) by using the plurality of magnetic sensors (<NUM>, <NUM>); and
a generated power supply unit (<NUM>) configured to supply power generated by each of the plurality of power generation elements (<NUM>, <NUM>) only to the corresponding one of the plurality of magnetic sensors (<NUM>, <NUM>).