JP7301698B2 - MOTOR, MOTOR DRIVE CONTROL DEVICE, AND MOTOR DRIVE CONTROL METHOD - Google Patents

Description

The present invention relates to a motor, a motor drive control device, and a motor drive control method.

In general, a motor is provided with a Hall sensor such as a Hall IC to detect operation information of the rotation axis of the motor such as the position and speed of the rotation axis, and a drive control device drives and controls the motor based on the detected operation information of the rotation axis. It is known how to However, there is room for improvement in the durability (environmental resistance) of Hall sensors used to detect the position and speed of the rotating shaft of a motor against vibrations and impacts.

Therefore, a motor equipped with a strain gauge or other strain sensor (hereinafter simply referred to as a “strain sensor”) that is considered to have better environmental resistance than a Hall sensor as a sensor that detects the operation of the rotation shaft of the motor. is known (see Patent Document 1).

WO2014/147757

By the way, in the motor drive system of Patent Document 1, a strain sensor is attached to the stator. Here, in the motor, the rotation of the magnet attracts the stator and causes distortion. In the motor drive system of Patent Document 1, the strain sensor outputs an electrical signal according to this strain.

However, in the motor drive system of Patent Document 1, the electrical signal output by the strain sensor is two pulses per rotation (one cycle) when the magnet has two poles, for example. For this reason, the motor drive system of Patent Document 1 outputs one pulse per rotation and is difficult to use for detecting operation information of the rotating shaft of the motor like a Hall sensor that can also specify the polarity. .

SUMMARY OF THE INVENTION It is an object of the present invention to provide a motor, a motor drive control device, and a motor drive control method, which are provided with a strain sensor capable of detecting the motion of a rotating shaft.

To achieve the above object, a motor according to the present invention includes a motor main body that rotates a rotating shaft, and a sensor unit that detects rotation of the rotating shaft, wherein the sensor unit detects rotation of the rotating shaft. A first magnet rotatably supported on a shaft, a second magnet reacting to the magnetic pole and magnetic force that change according to the rotational position of the first magnet, and distortion occurring according to the reaction of the second magnet. It has a strain-generating section and a strain sensor that outputs a strain signal corresponding to the strain of the strain-generating section.

In the motor according to one aspect of the present invention, the second magnet is provided on the radially outer peripheral side of the first magnet.

In the motor according to one aspect of the present invention, the strain-generating portion is provided on the radially outer peripheral side of the second magnet, and the strain sensor is provided at a strain-generating portion of the strain-generating portion. .

In a motor according to an aspect of the present invention, the strain-generating portion is configured separately from the second magnet.

In the motor according to one aspect of the present invention, the motor main body includes a rotor including the rotating shaft and a rotor magnet rotatably supported by the rotating shaft, and arranged to face the rotor in a radial direction. and a case portion that houses the rotor and the stator. It has a strain-flexing portion main body that is distorted according to change, and a support portion that supports the radially outer peripheral end portion of the strain-flexing portion main body on the case portion.

In the motor according to one aspect of the present invention, the strain sensor is arranged at the outer peripheral end portion of the strain-generating portion main body.

In the motor according to one aspect of the present invention, the second magnet is magnetized in the radial direction of the rotating shaft.

In the motor according to an aspect of the present invention, the magnetic poles of the first magnet are equally spaced in the circumferential direction around the rotation shaft.

In the motor according to one aspect of the present invention, the first magnet is arranged at a position where the magnetic poles face each other toward the center of the rotating shaft on the outer peripheral portion in the radial direction.

In order to achieve the above object, a motor drive control device according to the present invention includes a rotational position signal processing circuit for outputting a position signal indicating the rotational position of a rotary shaft of a motor; and a control unit for outputting a control signal for controlling the number of rotation position signals, wherein the rotation position signal processing circuit processes a strain signal output by a strain sensor included in the sensor unit of the motor and outputs the position signal. do.

In the motor drive control device according to one aspect of the present invention, the rotational position signal processing circuit is configured to detect positions in the circumferential direction of the magnetic poles of the first magnets that are equally spaced in the circumferential direction about the rotation axis. and outputting the position signal by processing the distortion signal that changes according to the position.

To achieve the above object, a motor drive control method according to the present invention includes a rotational position signal processing step of outputting a position signal indicating the rotational position of a rotary shaft of a motor; and a control step of outputting a control signal for controlling the number, and in the rotational position signal processing step, a strain signal output by a strain sensor included in the sensor unit of the motor is processed to generate the position signal. Output.

According to the motor of the present invention, it is possible to provide a motor equipped with a strain sensor capable of detecting the motion of a rotating shaft, a motor drive control device, and a motor drive control method.

1 is a perspective view schematically showing the configuration of a motor according to an embodiment of the invention; FIG. 2 is a side view of the motor shown in FIG. 1; FIG. 2 is a top view of the motor shown in FIG. 1; FIG. FIG. 2 is a cross-sectional view taken along line AA of the motor shown in FIG. 1, viewed from the side; 2 is a schematic diagram showing the relationship between the sensor unit of the motor shown in FIG. 1 and the rotational position of the rotary shaft; FIG. 3 is a diagram showing the relationship between the waveform of the amount of strain output by the strain sensor of the sensor unit of the motor shown in FIG. 1 and the rotational position of the rotary shaft; FIG. 1 is a functional block diagram schematically showing the configuration of a motor drive control device according to an embodiment of the invention; FIG.

A motor, a motor drive control device, and a motor drive control method according to embodiments of the present invention will be described below with reference to the drawings.

[Motor configuration]
FIG. 1 is a perspective view schematically showing the construction of a motor 1 according to an embodiment of the invention. FIG. 2 is a side view of the motor 1. FIG. 3 is a top view of the motor 1. FIG. FIG. 4 is a cross-sectional view of the motor 1 taken along the line AA.

In the following description, for the sake of convenience, the direction of the arrow a in the direction of the axis x is defined as the upper side a, and the direction of the arrow b is defined as the lower side b. In the radial direction perpendicular to the axis x, the direction away from the axis x (the direction of the arrow c in FIG. 4) is defined as the outer peripheral side c, and the direction toward the axis x (the direction of the arrow d in FIG. 4) is defined as the inner peripheral side d. . In the following description, the direction shown in FIG. 2 is the side of the motor. In the following description, as shown in FIG. 3, the direction of viewing the motor from the top to the bottom is the top surface, and the direction of viewing the motor from the bottom to the top is the bottom surface.

As shown in FIGS. 1 and 2, a motor 1 according to this embodiment includes a motor body 10 that rotates a rotating shaft 11 and a sensor unit 20 that detects the rotation of the rotating shaft 11 . As shown in FIGS. 1 and 3, the sensor unit 20 includes a first magnet 211 rotatably supported on the rotating shaft 11, a second magnet 212 reacting to the magnetic force generated by the first magnet 211, and a first magnet 212. The magnet 211 and the second magnet 212 have a strain-generating portion 22 that generates strain according to the magnetic force that reacts with them, and a strain sensor 23 that outputs a strain signal according to the strain of the strain-generating portion. The configuration and operation of the motor 1 will be specifically described below.

[Configuration of motor body]
As shown in FIG. 4, the motor body 10 is, for example, an inner rotor type brushless DC (Direct Current) motor in which a rotating shaft 11 and a rotor magnet 12 attached to the rotating shaft 11 constitute a rotor. In the motor 1, a motor body 10 has a stator 13, bearing portions 14a and 14b, and a case portion 15 in addition to the rotating shaft 11 and rotor magnet 12 described above.

The rotor magnet 12 is rotatably supported with respect to the rotating shaft 11 . The stator 13 is arranged on the radially outer peripheral side of the rotor including the rotor magnet 12 . The stator 13 is arranged such that its inner peripheral surface faces the outer peripheral surface of the rotor magnet 12 .

The stator 13 is fixed to, for example, the lower side b of the case portion 15 . Specifically, the stator 13 includes a coil wound around a stator core formed by laminating a plurality of electromagnetic steel plates (not shown) via an insulator.

As shown in FIG. 4, the bearings 14a and 14b are formed of a pair of bearings spaced apart in the axis x direction of the rotating shaft 11. As shown in FIG. The bearing portion 14 a supports the upper side a of the rotating shaft 11 . The bearing portion 14b supports a lower side b of the rotating shaft 11 than the bearing portion 14a.

Each of the bearing portions 14a and 14b has inner rings 141a and 141b, outer rings 142a and 142b, and rolling elements 143a and 143b. The inner rings 141 a and 141 b are annular members having inner peripheral surfaces that can be attached to the outer peripheral surface of the rotating shaft 11 . The inner rings 141 a and 141 b are rotatable together with the rotating shaft 11 by being mounted on the outer peripheral surface of the rotating shaft 11 . The outer rings 142a, 142b are provided on the outer peripheral side c of the inner rings 141a, 141b. The outer rings 142a and 142b are annular members coaxial with the inner rings 141a and 141b and having a larger diameter than the inner rings 141a and 141b. The rolling elements 143a, 143b are spherical members arranged between the inner rings 141a, 141b and the outer rings 142a, 142b.

As shown in FIG. 4 , the case portion 15 accommodates the rotor including the rotor magnet 12 and the stator 13 . The case portion 15 has a first case portion 151 and a second case portion 152 . The first case portion 151 accommodates the rotating shaft 11 via the bearing portions 14 a and 14 b and supports the stator 13 of the motor body 10 . The second case portion 152 supports the first case portion 151 and the later-described strain-generating portion 22 of the sensor unit 20 .

The first case portion 151 has, for example, a bearing housing 153 that accommodates the rotary shaft 11 and the bearing portions 14 a and 14 b, and a stator support portion 154 that supports the stator 13 . The bearing housing 153 is a hollow cylindrical portion supported by a central axis that is coaxial or substantially coaxial with the axis x of the second case portion 152 . The bearing housing 153 rotatably supports the rotary shaft 11 via a pair of bearings 14a and 14b. The bearing housing 153 has a bearing support portion 155a that supports the bearing portion 14a at one end (upper side a) in the direction of the axis x, and a bearing support portion 155b that supports the bearing portion 14b at the other end (lower side b) in the direction of the axis x. Prepare. The bearing support portions 155a and 155b are formed on the inner peripheral surface of the bearing housing 153, respectively. The stator support portion 154 is formed so as to be connected to the other end side (lower side b) of the bearing housing 153 in the direction of the axis x where the bearing support portion 155b is provided. The stator support portion 154 is formed in a tubular or substantially cylindrical shape having a diameter that is expanded radially outward from the bearing housing 153 . The stator 13 is supported on the inner peripheral surface of the lower side b of the stator support portion 154 .

The second case portion 152 is a base portion that supports the strain-generating portion 22 of the sensor unit 20 on one side (upper side a) in the direction of the axis x of the second case portion main body 156 formed in a cylindrical shape or a substantially cylindrical shape. 157 are formed. The base portion 157 has a shaft hole portion 158 formed at a position corresponding to the axis x, through which one end portion of the rotating shaft 11 can be inserted. Further, the second case portion 152 has a bearing housing accommodating portion 159 that accommodates the bearing housing 153 of the first case portion 151 on the inner peripheral surface of the second case portion main body 156 .

The motor 1 according to the present embodiment is not limited to the inner rotor type or outer rotor type, DC motor or AC motor, and specifications such as the number of phases and the number of poles.

[Configuration of sensor unit]
In the sensor unit 20, as shown in FIGS. 1 to 4, the first magnet 211 is rotatably supported by the rotary shaft 11. As shown in FIGS. Further, as shown in FIG. 3, the sensor unit 20 has the strain generating portion 22 provided with the strain sensor 23 supported by the base portion 157 of the second case portion 152 as described above.

As shown in FIG. 3, the first magnet 211 is configured such that the magnetization direction is outward from the central axis x so as to emit magnetic flux toward the radially outer side. In the first magnet 211, two magnetic poles (two poles) of an N pole and an S pole are arranged equally in a range of, for example, 180° with respect to the circumferential direction around the rotating shaft 11. It is In other words, the first magnet 211 has a pair of N poles and S poles arranged at positions opposed to each other toward the center of the rotating shaft 11 on the outer peripheral portion 216 . The number of magnetic poles of the first magnet 211 is not limited to the above example, and there may be two or more combinations of two magnetic poles.

The first magnet 211 is formed of, for example, one ring-shaped (doughnut-shaped) magnet centered on the rotating shaft 11 . In addition, the first magnet 211 may generate magnetic fluxes of N pole and S pole on the radially outer peripheral side by combining a plurality of, for example, four divided ones.

The second magnet 212 is provided at a position where it reacts (attracts or repels) to the magnetic pole and magnetic force that change according to the rotational position of the first magnet 211 , for example, on the radially outer peripheral side of the first magnet 211 . The second magnet 212 is configured, for example, so that the radially outer peripheral side away from the first magnet 211 in FIG. , are magnetized in the radial direction of the rotating shaft 11 . Here, if the magnetic poles of the second magnet 212 are magnetized in the radial direction, the inner peripheral side, that is, the magnetic poles close to the outer peripheral portion 216 of the second magnet 212 are the N pole and the S pole. may be either. The second magnet 212 responds to the magnetic pole and magnetic force that change according to the rotational position of the first magnet 211 as described above, and thus is composed of, for example, a magnet. It should be noted that the second magnet 212 may be composed of an electromagnet with a coil, as long as it can generate a magnetic force.

For example, one strain generating portion 22 is provided on the radially outer peripheral side of the rotating shaft 11 . Specifically, one strain generating portion 22 is provided at a position toward the center of the rotating shaft 11 . The strain sensor 23 is provided in the strain-generating portion 22 . The strain-flexing portion 22 has a strain-flexing portion main body 221 and a support portion 222 . In FIG. 3 , the dashed line indicates a portion of the strain-flexing portion 22 that functions as the strain-flexing portion main body 221 . The strain-flexing portion 22 is formed by integrally forming a strain-flexing portion main body 221 and a support portion 222 . The strain-generating portion 22 may be made of any material that can be distorted by the reaction of the second magnet 212 . In addition, the strain-generating part 22 is not limited to the one configured separately from the second magnet 212 which is formed of an electromagnet with a magnet or a coil as shown in FIGS. The strain-generating portion 22 as a whole may be formed of an electromagnet composed of magnets or coils. In addition, the strain-flexing portion main body 221 and the support portion 222 do not necessarily need to be integrally formed. good.

The strain-generating portion main body 221 is formed to extend from the radially outer peripheral side of the support portion 222 toward the center of the rotating shaft 11 . As described above, the strain-generating portion main body 221 rotates the first magnet 211 together with the rotating shaft 11 , so that the second magnet 212 changes its magnetic pole and magnetic force according to the rotational position of the first magnet 211 . It is made of a material that causes distortion due to reaction. The strain-generating portion main body 221 is formed with a concave portion corresponding to the external shape of the second magnet 212 so that the distal end portion 224 can accommodate a portion of the second magnet 212, for example, the radially outer peripheral side. . The shape of the strain-generating portion main body 221 is not limited to the shapes shown in FIGS. Furthermore, in the strain-flexing portion 22, the strain direction of the strain-flexing portion main body 221 is not particularly limited.

The support portion 222 supports the radially outer peripheral end portion 223 of the strain-flexing portion main body 221 on the base portion 157 of the second case portion 152 of the case portion 15 . The support portion 222 may have any shape as long as the strain-generating portion main body 221 can be fixed to the motor main body 10 side. Further, the shape of the support portion 222 is not limited to being formed in an arc shape or a substantially arc shape as described above. In addition, when the supporting portion 222 is divided and formed, the phase of the distortion output can be adjusted by adjusting the attachment position to the base portion 157 .

The strain sensor 23 is disposed at a location where strain is generated in the strain-generating portion 22 in accordance with the reaction of the second magnet 212 , for example, the outer peripheral end portion 223 of the strain-generating portion main body 221 . Specifically, it is desirable to attach the strain sensor 23 at a position where the strain is maximized when the strain sensor 23 is at the center of the N pole or S pole magnetic line of force. The strain sensor 23 is a sensor such as a strain gauge, a piezoelectric element, or the like that detects strain occurring in a member to which it is attached and outputs an electrical signal that changes according to the detected strain.

Note that the strain sensor 23 may be attached to a portion of the strain-generating portion 22 that produces a desired strain according to the reaction of the second magnet 212, and is not limited to the above-described portion. Also, the strain sensor 23 can be attached in a direction that is adjusted according to the direction of strain generated in the strain-generating portion main body 221 . Moreover, the strain sensor 23 is not limited to a strain gauge as long as it can output an electrical signal that changes according to strain. Moreover, in the sensor unit 20, the number of strain-generating portions and strain sensors attached is not limited to one. A sensor may be provided.

[Motor operation]
Next, the operation of the motor 1 having the configuration described above will be described.

Motor 1 rotates rotary shaft 11 when drive current flows. A rotating shaft 11 of the motor 1 is rotatably supported by a pair of bearings 14a and 14b mounted in a bearing housing 153, as shown in FIGS. The first magnet 211 of the sensor unit 20 is attached rotatably along with the rotating shaft 11 . Therefore, when the motor 1 is driven, the rotating shaft 11 rotates about the axis x, and accordingly the first magnet 211 also rotates about the axis x.

FIG. 5 is a schematic diagram showing the relationship between the sensor unit 20 of the motor 1 and the rotational position of the rotary shaft 11. As shown in FIG. FIG. 5 shows only the rotary shaft 11 of the motor body 10 and the sensor unit 20 provided in the motor 1. FIG. In the following description, the state in which the N pole of the second magnet 212 of the sensor unit 20 is close to the N pole of the first magnet 211 is assumed to be the rotation angle θ=0°.

As shown in FIG. 5, in the sensor unit 20, the vicinity of the midpoint of the N pole of the first magnet 211 faces the N pole of the second magnet 212 in the radial direction when the rotation angles θ=0° and 360°. ing. At this time, an N-pole magnetic force is generated from the radially outer peripheral side of the first magnet 211 toward the second magnet 212 attached to the distal end portion 224 of the strain-generating section main body 221 of the strain-generating section 22 . . Since the N pole of the second magnet 212 is arranged radially inwardly as described above, the second magnet 212 and the N pole of the first magnet 211 repel each other. The strain-generating portion 22 including the strain-generating portion main body 221 is distorted radially outward due to the magnetic force that the second magnet 212 receives from the first magnet 211 .

FIG. 6 is a diagram showing the relationship between the waveform of the strain amount ε output by the strain sensor 23 of the sensor unit 20 of the motor 1 and the rotational position of the rotary shaft 11. As shown in FIG. In FIG. 6 , the horizontal axis indicates the rotation angle θ of the rotating shaft 11 and the first magnet 211 . In addition, in FIG. 6, the vertical axis indicates the strain amount ε output by the strain sensor 23 .

As shown in FIG. 6, the strain sensor 23 detects the amount of strain corresponding to each position based on the relationship between the rotational position of the first magnet 211 attached to the rotating shaft 11 and the position of the second magnet 212. It outputs an electrical signal (distortion signal) indicating Specifically, when the rotation angle θ is 0° and 360°, the second magnet 212 attached to the strain-generating portion 22 repels the first magnet 211 , so that the second magnet 212 is attached to the strain-generating portion main body 221 . The strain amount ε output by the strain sensor 23 is the largest in the extension direction (plus direction).

As shown in FIG. 5, when the rotation angle θ=180°, the vicinity of the midpoint of the S pole of the first magnet 211 faces the N pole of the second magnet 212 in the radial direction. At this time, the magnetic force of the south pole is generated from the outer peripheral portion 216 of the first magnet 211 toward the second magnet 212 attached to the tip portion 224 . The second magnet 212 is attracted to the S pole of the first magnet 211 because the N pole is arranged radially inward as described above. The strain-generating portion 22 including the strain-generating portion main body 221 is distorted radially inward by the magnetic force that the second magnet 212 receives from the first magnet 211 .

As shown in FIG. 5, when the rotation angle θ=180°, the second magnet 212 attached to the strain-generating portion 22 is attracted to the first magnet 211, and as shown in FIG. The strain amount ε output by the strain sensor 23 attached to the portion main body 221 has the largest value in the pulling direction (negative direction).

In the sensor unit 20, when the rotation angles θ=90° and 270°, the vicinity of the midpoint of the N pole or S pole of the first magnet 211 is located away from the strain-generating portion main body 221 in the circumferential direction. At this time, a strong magnetic pole magnetic force generated from the radially outer peripheral side of the first magnet 211 is generated toward the intermediate position. Therefore, the second magnet 212 attached to the strain-generating portion 22 is attracted or repelled by a weaker magnetic flux than when the rotation angles θ = 0°, 180°, and 360°, and strains according to the magnetic flux. occurs.

As shown in FIG. 6, the motor 1 detects the strain amount ε of the strain sensor 23 of the sensor unit 20 according to one cycle of one rotation (360°) of the rotating shaft 11 based on the strain amount ε output by the strain sensor 23 . It is possible to acquire a waveform that shows the change in This waveform can be recognized as a signal that outputs one pulse for each rotation of the rotary shaft 11, that is, as a distortion signal. A signal (distortion signal) representing the amount of distortion ε output by the distortion sensor 23 is a signal corresponding to the number of magnetic poles equally arranged on the first magnet 211 .

FIG. 7 is a functional block diagram schematically showing the configuration of motor drive control device 30 according to the embodiment of the present invention. The motor drive control device 30 executes the method of controlling the drive of the motor 1 (motor drive control method) described above. The motor drive control device 30 is, for example, an MCU (Micro Controller Unit), an information processing device capable of executing various computer programs including programs for realizing the following functional blocks by the motor drive control device according to the present invention. and a storage device such as a ROM (Read Only Memory) that stores computer programs and data when the programs are executed.

As shown in FIG. 7, the motor drive control device 30 includes a rotation position signal processing circuit 31, a control section 32, a PWM signal generation circuit 33, and a motor drive section .

A rotational position signal processing circuit 31 functioning as a rotational position signal processing unit amplifies a strain signal according to the amount of strain ε generated in the strain-generating portion 22, which is output by the strain sensor 23 of the sensor unit 20 of the motor 1. do. Further, the rotational position signal processing circuit 31 converts the distortion signal, which is an analog signal output from the distortion sensor 23, into a digital signal by A/D conversion processing. As described above, each time the rotating shaft 11 of the motor main body 10 of the motor 1 makes one rotation, the strain signal is generated so that the magnetic poles of the N pole and the S pole are arranged equally in the circumferential direction around the rotating shaft 11. It changes according to the position in the circumferential direction of the first magnet 211 . As shown in FIG. 6, the distortion signal outputs a pulse waveform with one period per rotation. Then, the rotational position signal processing circuit 31 outputs a position signal indicating the rotational position of the rotary shaft 11 according to this distortion signal.

The control unit 32 outputs a control signal (PWM data) for controlling the rotation speed of the motor 1 according to the position signal, that is, a signal for setting the pulse width necessary to drive the motor 1 at a desired rotation speed. do.

The PWM signal generation circuit 33 outputs a PWM signal to the motor drive section 34 based on the control signal output from the control section 32 .

The motor drive section 34 outputs a drive signal for driving the motor 1 based on the PWM signal output from the PWM signal generation circuit 33 .

As described above, in the motor 1, the sensor unit 20 for detecting the rotation of the rotating shaft 11 of the motor main body 10 is rotatably supported by the rotating shaft 11, and the rotation position of the first magnet 211 is detected. a second magnet 212 that responds to the magnetic pole and the magnetic force that change according to the second magnet 212; a strain-generating portion 22 that generates strain according to the reaction of the second magnet 212; and a strain sensor 23 . According to the motor 1 configured in this manner, the first magnet 211 and the second magnet 212 allow the rotation of the rotating shaft 11 to move the strain-generating portion 22 to which the strain sensor 23 is attached according to the rotation of the rotating shaft 11 . By generating a periodic distortion of one pulse in response to one rotation, the position of the rotating shaft 11 and the speed of the rotating shaft 11 can be detected based on this position. In addition, according to the motor 1, the first magnet 211 attached to the rotating shaft 11 and the magnetic pole and magnetic force attached to the outer peripheral side in the radial direction of the first magnet 211 change according to the rotational position of the first magnet 211. and a strain sensor 23 that outputs a strain signal according to the strain generated in the strain-generating portion 22 according to the reaction (repulsion or attraction) of the second magnet 212, the position of the rotating shaft 11 can be determined. can be detected.

In the motor 1, the strain-generating portion 22 to which the second magnet 212 is attached is provided, for example, at a position facing toward the center of the rotating shaft 11, and the strain sensor 23 is provided in the strain-generating portion 22. ing. Therefore, according to the motor 1, one strain signal corresponding to the strain amount ε generated in the strain-generating portion 22 can be detected.

In addition, those skilled in the art can appropriately modify the configuration of the motor of the present invention according to conventionally known knowledge. As long as the configuration of the present invention is still provided even with such modification, it is, of course, included in the scope of the present invention.

For example, the first magnet 211 is preferably formed in an annular shape as described above, but its shape is not limited.

Further, for example, when a plurality of strain-generating portions 22 and strain sensors 23 are provided, noise included in the strain amount ε is compared by comparing the strain amount ε output by the plurality of strain sensors 23 . cancellation processing, or temperature compensation processing for the value of the strain amount ε.

DESCRIPTION OF SYMBOLS 1... Motor, 10... Motor main body, 11... Rotating shaft, 12... Rotor magnet, 13... Stator, 14a, 14b... Bearing part, 15... Case part, 20... Sensor unit, 22... Strain generating part, 23... Strain sensor , 30... Motor drive control device 31... Rotational position signal processing circuit 32... Control unit 33... Signal generation circuit 34... Motor drive unit 141a, 141b... Inner ring 142a, 142b... Outer ring 143a, 143b... Roller Moving body 151 First case portion 152 Second case portion 153 Bearing housing 154 Stator support portion 155a, 155b Bearing support portion 156 Second case main body 157 Base portion 158 Axial hole portion 159 Bearing housing accommodating portion 211 First magnet 212 Second magnet 216 Peripheral portion 221 Strain generating portion main body 222 Support portion 223 Peripheral end 224 Tip

Claims (9)

A motor comprising a motor body that rotates a rotating shaft and a sensor unit that detects rotation of the rotating shaft,
The sensor unit is
a first magnet rotatably supported by the rotating shaft;
a second magnet that responds to magnetic poles and magnetic forces that change according to the rotational position of the first magnet;
a strain-generating portion that generates strain according to the reaction of the second magnet;
a strain sensor that outputs a strain signal corresponding to the strain of the strain-generating portion;
and
The motor body is
a rotor including the rotating shaft and a rotor magnet rotatably supported by the rotating shaft;
a stator disposed radially facing the rotor;
a case portion housing the rotor and the stator;
and
The second magnet is provided on the radially outer peripheral side of the first magnet,
The strain-generating portion is
a strain-generating portion main body formed so as to extend toward the center from the radially outer peripheral side of the second magnet, and which is distorted according to a change in the magnetic pole;
a support portion that supports the radially outer peripheral end portion of the strain-generating portion main body on the case portion;
and
The motor , wherein the strain sensor is arranged at the outer peripheral end portion of the strain-generating portion main body . The strain sensor is provided at a strain generating location in the strain-generating portion,
A motor according to claim 1 . The strain-generating portion is configured separately from the second magnet,
A motor according to claim 1 or 2 . The second magnet is magnetized in a radial direction of the rotating shaft,
A motor according to any one of claims 1 to 3 . The magnetic poles of the first magnet are equally spaced in the circumferential direction around the rotation axis,
A motor according to any one of claims 1 to 4 . The first magnet is arranged at a position where the magnetic poles face toward the center of the rotating shaft on the outer peripheral portion in the radial direction.
A motor according to any one of claims 1 to 5 . a rotational position signal processing circuit that outputs a position signal indicating the rotational position of the rotary shaft of the motor;
a control unit that outputs a control signal for controlling the rotation speed of the motor according to the position signal;
A motor drive control device comprising
The motor is the motor according to any one of claims 1 to 6 ,
The rotational position signal processing circuit processes a strain signal output by the strain sensor included in the sensor unit of the motor and outputs the position signal.
Motor drive controller. The rotational position signal processing circuit processes the distortion signal that changes according to the position in the circumferential direction of the magnetic poles of the first magnets, which are equally spaced in the circumferential direction about the rotation axis. to output a position signal,
The motor drive control device according to claim 7 . a rotational position signal processing step of outputting a position signal indicating the rotational position of the rotary shaft of the motor;
a control step of outputting a control signal for controlling the rotation speed of the motor according to the position signal;
A motor drive control method for executing
The motor is the motor according to any one of claims 1 to 6 ,
In the rotational position signal processing step, the strain signal output by the strain sensor included in the sensor unit of the motor is processed and the position signal is output.
Motor drive control method.

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