JP7336329B2 - 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 body that rotates a rotating shaft, and a sensor unit that detects rotation of the rotating shaft, the sensor unit being rotatable about the rotating shaft. a rotation detecting magnet supported by a magnet; a strain-generating portion provided on the radially outer peripheral side of the rotation detecting magnet and generating distortion according to a change in magnetic pole due to rotation of the rotation detecting magnet; and a strain sensor provided in the strain-generating portion for outputting a strain signal corresponding to the strain of the strain-generating portion.

In a motor according to an aspect of the present invention, a plurality of strain-generating sections are provided, and the strain sensor is provided for each of the strain-generating sections.

In the motor according to one aspect of the present invention, a synthesized signal obtained by synthesizing strain signals output from each of the plurality of strain sensors corresponds to one rotation of the rotating shaft.

In the motor according to an aspect of the present invention, two strain-generating portions are provided as one set at positions facing each other toward the center of the rotating shaft.

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 rotation detection magnet has two poles on a radially outer peripheral portion and a radially inner peripheral portion.

In the motor according to an aspect of the present invention, the rotation detection magnet has one magnetic flux and the other magnetic flux at positions facing each other toward the center of the rotation shaft.

In the motor according to one aspect of the present invention, the rotation detection magnet is configured by combining a plurality of magnets.

In the motor according to one aspect of the present invention, the rotation detection magnet is formed in an arc shape of 180 degrees or more around the rotation shaft.

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.

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; 4 is an enlarged top view of the sensor unit shown in FIG. 3; FIG. FIG. 6 is a top view of the rotation detection magnet shown in FIG. 5; 4 is a schematic diagram showing the relationship between the sensor unit shown in FIG. 3 and the rotational position of the rotary shaft; FIG. 2 is a diagram showing the relationship between the waveform output by a strain sensor included in the sensor unit of the motor shown in FIG. 1 and the rotational position of the rotary shaft; FIG. FIG. 9 is a diagram showing the relationship between a synthesized waveform obtained by synthesizing the waveforms of the strain sensors shown in FIG. 8 and the rotational position of the rotating shaft; 1 is a functional block diagram schematically showing the configuration of a motor drive control device according to an embodiment of the invention; FIG.

Hereinafter, a motor, a motor drive control device, and a motor drive control method according to embodiments of the present invention will be described 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 the present embodiment includes a motor body 10 that rotates a rotating shaft 11 and a sensor unit 20 that detects rotation of the rotating shaft 11. As shown in FIGS. As shown in FIGS. 1 and 3, the sensor unit 20 includes a rotation detection magnet 21 rotatably supported by the rotation shaft 11, and a magnetic body. and strain sensors 23a and 23b provided in the strain-generating portions 22a and 22b for outputting strain signals according to the strain of the strain-generating portions 22a and 22b. . 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.

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

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 supports the strain-generating portions 22a and 22b 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. A base portion 157 is 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]
As shown in FIGS. 1 to 4, the sensor unit 20 has a rotation detecting magnet 21 rotatably supported on the rotating shaft 11. As shown in FIGS. Further, as shown in FIG. 3, in the sensor unit 20, the strain generating portions 22a and 22b provided with the strain sensors 23a and 23b are supported by the base portion 157 of the second case portion 152 as described above. .

FIG. 5 is an enlarged top view of the sensor unit 20. FIG. As shown in FIG. 5 , the rotation detection magnet 21 has a magnet portion 211 and a magnet cover 212 . The rotation detection magnet 21 is configured such that the magnetization direction is the outer peripheral side from the axis x at the center of the magnet portion 211 so as to emit magnetic flux toward the outer peripheral side in the radial direction. For this reason, the rotation detecting magnet 21 has two poles at positions facing toward the center of the rotating shaft 11 , that is, an outer peripheral portion 216 having an N pole and an inner peripheral portion 217 facing the rotating shaft 11 having an S pole. are placed.

FIG. 6 is a top view of the rotation detection magnet 21. FIG. As shown in FIG. 6 , the magnet section 211 is composed of a plurality of magnets 2111 . By combining a plurality of magnets 2111, for example, four divided magnets 2111 as described above, the magnet portion 211 generating magnetic fluxes on the radially outer and inner peripheral sides of the rotation detecting magnet 21 is formed. Configure.

As described above, the magnets 2111 are configured such that all of the magnets 2111 have the same poles on the outer peripheral side and the inner peripheral side (for example, the N pole on the outer peripheral side and the S pole on the inner peripheral side). The magnet 2111 is equally divided at a central angle β1. The magnets 2111 are each formed, for example, in an arc shape on the outer peripheral side so as not to cause resistance when attached to the rotating shaft 11 and rotated. Also, the magnet 2111 is formed with an arc-shaped notch for inserting the rotating shaft 11 at the position where the inner peripheral portion 217 is formed on the inner peripheral side. Therefore, the magnets 2111 are each formed in a sector shape.

The magnet cover 212 has a circular circumferential shape on the radially outer side, and an insertion hole 214 through which the rotary shaft 11 can be inserted is formed in the center. The magnet cover 212 has the magnets 2111 arranged in a sector shape so that a plurality of the magnets 2111 in the rotation detection magnet 21 can be combined to form a sector-shaped magnet portion 211 with a central angle β2 around the rotation shaft 11 . It has an accommodation portion 215 that accommodates the magnet portion 211 in a shape of . Note that the shape of the accommodation portion 215 is determined in accordance with the shape of the magnet portion 211 to be accommodated, and is not limited to the shape described above.

As described above, the rotation detection magnet 21 is held by the magnet cover 212 by combining a plurality of sector-shaped magnets 2111 equally divided by the central angle β1, for example, to form the magnet portion 211. are doing. For this reason, the magnet portion 211 of the rotation detection magnet 21 is formed in a fan shape centered on the rotation shaft 11 with a central angle β2=180° or more. Here, in the rotation detecting magnet 21, the angle range of both ends exceeding 180° in the center angle β2 of the magnet portion 211 arranged in an arc shape is called an overlap angle α. Also, in the magnet portion 211 , an arc range corresponding to the overlap angle α is defined as an overlapping portion 213 . For example, when β2=210°, the magnet portion 211 has an overlap angle α=15°. Note that the central angle β1 of the magnet 2111, the central angle β2 of the magnet portion 211, and the overlap angle α are not limited to the values described above.

With the above configuration, the rotation detection magnet 21 has two poles, the N pole and the S pole, and the magnetic flux of the N pole is stronger than the magnetic flux of the S pole on the outer peripheral surface. That is, in the rotation detection magnet 21, one magnetic flux and the other magnetic flux are different in the radial direction. In the rotation detection magnet 21, the magnetic pole width of the N pole, which is a strong magnetic pole, is wider than the magnetic pole width of the S pole, which is a weak magnetic pole, by a predetermined amount corresponding to the range of the overlapping portion 213, preferably 1.25 times or more. Further, it is desirable that the magnetic flux of the weak magnetic pole portion of the rotation detection magnet 21 is as close to zero as possible.

As shown in FIGS. 1 to 3 and 5, in the sensor unit 20, a plurality of, for example, two, strain-generating portions 22a and 22b are provided so as to divide the entire circumference of the rotating shaft 11. . Specifically, the strain-generating portions 22 a and 22 b are provided as a pair at positions facing each other toward the center of the rotating shaft 11 . The strain sensors 23a and 23b are provided in the strain generating portions 22a and 22b, respectively. The strain-flexing portions 22a and 22b respectively have strain-flexing portion bodies 221a and 221b and support portions 222a and 222b. In FIG. 3, dashed lines indicate portions of the strain-flexing portions 22a and 22b that function as the strain-flexing portion main bodies 221a and 221b. The strain-generating portions 22a and 22b are formed by integrally forming strain-generating portion main bodies 221a and 221b and supporting portions 222a and 222b from a magnetic material. The strain-generating portion main bodies 221a and 221b and the support portions 222a and 222b do not necessarily need to be integrally formed. Alternatively, they may be separate bodies.

The strain-generating portion main bodies 221a and 221b are formed so as to extend toward the center of the rotating shaft 11 from the radially outer peripheral sides of the support portions 222a and 222b. The strain-generating portion main bodies 221 a and 221 b have properties as magnetic bodies that are attracted (magnetically attracted) by magnets so that strain is generated according to magnetic pole changes caused by the rotation of the rotation detecting magnet 21 together with the rotating shaft 11 . are doing. The strain-generating part main bodies 221 a and 221 b may have distal ends 224 a and 224 b formed in an arc shape or a substantially arc shape corresponding to the shape of the outer peripheral surface of the rotation detection magnet 21 . The shape of the strain-generating portion main bodies 221a and 221b is not limited to the shapes shown in FIGS. Further, the strain-flexing portion main bodies 221a and 221b of the strain-flexing portions 22a and 22b are not particularly limited in the strain direction.

The supporting portions 222 a and 222 b support radially outer peripheral end portions 223 a and 223 b of the strain-generating portion bodies 221 a and 221 b on the base portion 157 of the second case portion 152 of the case portion 15 . The support portions 222a and 222b may have any shape as long as the strain generating portion main bodies 221a and 221b can be fixed to the motor main body 10 side. Further, the shape of the support portions 222a and 222b is not limited to those formed by being divided into circular or substantially circular arc shapes as described above, and the support portions 222a and 222b may be integrally formed. may When the support portions 222a and 222b are divided and formed, the phase of each distortion output can be adjusted by adjusting the attachment position to the base portion 157. FIG.

The strain sensors 23a and 23b are arranged at locations where strain occurs in the strain-generating portions 22a and 22b according to changes in the magnetic poles, for example, at the outer peripheral end portions 223a and 223b of the support portions 222a and 222b. Specifically, when one strain sensor 23a is at the center of a strong magnetic pole (N pole in this embodiment), the other strain sensor 23b is at a weak magnetic pole (N pole in this embodiment). It is desirable to attach them to the support portion 222a and the support portion 222b so as to be positioned at the center of the S pole at the bottom. The strain sensors 23a and 23b are sensors, such as strain gauges and piezoelectric elements, that detect strain occurring in members to which they are attached and output electrical signals that change according to the detected strain.

The strain sensors 23a and 23b are not limited to the locations described above, as long as they are attached to the strain-generating portions 22a and 22b at locations where desired strain is generated in accordance with changes in the magnetic poles. Moreover, the strain sensors 23a and 23b can be attached in the same direction depending on the direction of strain generated in the strain-generating portions 22a and 22b such as the strain-generating portion main bodies 221a and 221b. Moreover, the strain sensors 23a and 23b are not limited to strain gauges as long as they can output electrical signals that change according to strain. Also, the number of strain sensors attached to the sensor unit 20 is not limited to two.

[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. A rotation detection magnet 21 of the sensor unit 20 is attached rotatably along with the rotating shaft 11 . Therefore, when the motor 1 is driven, the rotary shaft 11 rotates about the axis x, and accordingly the rotation detecting magnet 21 also rotates about the axis x.

FIG. 7 is a schematic diagram showing the relationship between the sensor unit 20 and the rotational position of the rotary shaft 11. As shown in FIG. FIG. 7 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 strain sensor 23a of the sensor unit 20 is close to the strong magnetic pole of the rotation detection magnet 21, ie, the rotation angle θ=0°.

As shown in FIG. 7, in the sensor unit 20, when the rotation angle θ is 0° and 360°, the vicinity of the middle point of the center angle β2 of the magnet portion 211 of the rotation detection magnet 21 is the tip portion of the strain-generating portion main body 221a. 224a (see FIG. 5) in the radial direction. At this time, a strong magnetic pole (N pole) magnetic flux is generated from the radially outer peripheral side of the magnet portion 211 toward the strain-generating portion body 221a of the strain-generating portion 22a. Since the strain-generating portion 22 a including the strain-generating portion main body 221 a is made of a magnetic material as described above, it is attracted by the magnetic flux generated from the magnet portion 211 of the rotation detecting magnet 21 .

FIG. 8 is a diagram showing the relationship between the waveforms output by the strain sensors 23a and 23b of the sensor unit 20 of the motor 1 and the rotational position of the rotating shaft 11. As shown in FIG. In FIG. 8, the horizontal axis indicates the rotation angle .theta. In FIG. 8, the vertical axis indicates the strain amount ε1 output by the strain sensor 23a and the strain amount ε2 output by the strain sensor 23b.

As shown in FIG. 8, the strain sensors 23a and 23b correspond to respective positions according to the positional relationship between the rotational position of the rotation detection magnet 21 attached to the rotating shaft 11 and the strain-generating portions 22a and 22b. An electrical signal (distortion signal) indicating the amount of distortion applied is output. Specifically, when the strain-generating portion 22a is attracted to the magnet portion 211 of the rotation detecting magnet 21, the strain sensor 23a attached to the strain-generating portion main body 221a is pulled when the rotation angle θ is 0° and 360°. The distortion amount ε1 output by is the largest value.

On the other hand, when the rotation angles θ=0° and 360°, the strain-generating portion 22b including the strain-generating portion main body 221b is separated from the magnetic flux generated from the radially outer peripheral side of the magnet portion 211 . Therefore, the force of attraction by the magnetic flux generated from the magnet portion 211 of the rotation detecting magnet 21 is weakened in the strain-generating portion 22b including the strain-generating portion main body 221b. Then, the strain amount ε2 output by the strain sensor 23b is the smallest.

As shown in FIG. 7, in the sensor unit 20, when the rotation angle θ=180°, the vicinity of the midpoint of the center angle β2 of the magnet portion 211 of the rotation detection magnet 21 is the tip end portion 224b (Fig. 5) in the radial direction. At this time, a magnetic flux of a strong magnetic pole (N pole) is generated from the radially outer peripheral side of the magnet portion 211 toward the strain-generating portion main body 221b of the strain-generating portion 22b. Since the strain-generating portion 22b including the strain-generating portion main body 221b is also formed of a magnetic material like the strain-generating portion 22a, it is most strongly attracted by the magnetic flux generated from the magnet portion 211 of the rotation detecting magnet 21. FIG.

As shown in FIG. 8, when the strain-generating portion 22b is attracted to the magnet portion 211 of the rotation detecting magnet 21, the strain sensor 23b attached to the strain-generating portion main body 221b is moved when the rotation angle θ=180°. The distortion amount ε2 to be output is the largest value.

On the other hand, the strain-generating portion 22 a including the strain-generating portion main body 221 a is separated from the magnetic flux generated from the radially outer peripheral side of the magnet portion 211 . Therefore, the force of attraction by the magnetic flux generated from the magnet portion 211 of the rotation detecting magnet 21 is weakened in the strain-generating portion 22a including the strain-generating portion main body 221a. Then, the strain amount ε2 output by the strain sensor 23a becomes the smallest.

In the sensor unit 20, when the rotation angles θ=90° and 270°, the vicinity of the midpoint of the center angle β2 of the magnet portion 211 of the rotation detection magnet 21 is in the circumferential direction between the strain-generating portion main body 221a and the strain-generating portion main body 221b. in the middle position. At this time, a strong magnetic pole magnetic flux generated from the radially outer peripheral side of the magnet portion 211 is generated toward the intermediate position. Therefore, the strain-generating portions 22a and 22b, including the strain-generating portion main bodies 221a and 221b, are attracted by weaker magnetic flux than when the rotation angles θ=0°, 180° and 360°.

In FIG. 8 , a range indicated by “Mg Edge” indicated by a dashed line is a range corresponding to the overlapping portion 213 of the magnet portion 211 of the rotation detection magnet 21 . In the range corresponding to the overlapping portion 213, the strain amounts ε1 and ε2 output by the strain sensors 23a and 23b are smaller than when the rotation angles θ=0°, 180° and 360°. Also, the strain amounts ε1 and ε2 take the same value or approximate values.

FIG. 9 shows the relationship between the combined waveform obtained by synthesizing the waveform of the amount of strain ε1 output by the strain sensor 23a and the waveform of the amount of strain ε2 output by the strain sensor 23b with the polarity reversed, and the rotational position of the rotating shaft 11. FIG. 4 is a diagram showing;

As shown in FIG. 9, the motor 1 combines the strain amount .epsilon.1 output by the strain sensor 23a and the strain amount .epsilon.2 output by the strain sensor 23b. It is possible to generate a composite waveform (composite signal) that indicates changes in the overall distortion amount ε. Here, the waveforms of the distortion amounts ε1 and ε2 are the same or similar values in the overlap portion 213 shown in FIG. Two waveforms can be synthesized based on This composite waveform can be recognized as a signal that crosses zero twice at intervals of 180 degrees each time the rotating shaft 11 rotates once. It should be noted that the values of the strain amount ε1 and the strain amount ε2 in the overlapping portion 213 may not necessarily be the same value. It suffices if it can be recognized as a signal that crosses zero times.

FIG. 10 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. 10, 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 .

The rotational position signal processing circuit 31 outputs strain corresponding to the strain amounts ε1 and ε2 generated in the strain generating portions 22a and 22b (see FIG. 5) output by the strain sensors 23a and 23b of the sensor unit 20 of the motor 1. Amplify the signal. Further, the rotational position signal processing circuit 31 converts the distortion signals, which are analog signals output from the distortion sensors 23a and 23b, into digital signals by A/D conversion processing. The rotational position signal processing circuit 31 combines the strain signals output from the strain sensors 23a and 23b as shown in FIG. 9 to generate a single waveform signal (composite signal). The synthesized waveform is a signal that outputs one pulse each time the rotating shaft 11 of the motor body 10 of the motor 1 rotates once, as described above. That is, the rotational position signal processing circuit 31 outputs a position signal indicating the rotational position of the rotating shaft 11 .

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 formed by the rotation detection magnet 21 rotatably supported by the rotating shaft 11 and the magnetic material, and the sensor unit 20 detects the rotation of the rotating shaft 11. It has strain-generating portions 22a and 22b provided on the radially outer peripheral side of the detection magnet 21, and strain sensors 23a and 23b that output strain signals corresponding to strains of the strain-generating portions 22a and 22b. According to the motor 1 configured in this manner, the rotation detection magnet 21 periodically distorts the strain-generating portions 22a and 22b having the strain sensors 23a and 23b in accordance with the rotation of the rotating shaft 11. The position of the rotating shaft 11 and the speed of the rotating shaft 11 can be detected based on this position.

The motor 1 has a plurality of strain-generating portions 22a and 22b, for example, two sets of which are provided at positions facing each other toward the center of the rotating shaft 11. 22a and 22b. Therefore, according to the motor 1, two strain signals corresponding to the strain amount ε1 and the strain amount ε2 can be detected. Further, according to the motor 1 , a distortion signal with a phase difference of 180° can be detected for the rotation angle θ of the rotary shaft 11 . Note that the number and arrangement of the strain-generating portions 22a and 22b are not limited to the above example as long as their positional relationships in the circumferential direction are associated with each other.

In the motor 1, the magnet portion 211 of the rotation detection magnet 21 has two poles, an N pole and an S pole, on the radially outer peripheral portion and the inner peripheral portion surrounding the rotating shaft 11. That is, the magnet portion 211 , the magnetization direction is toward the outer peripheral portion 216 . The magnet portion 211 of the rotation detection magnet 21 is configured such that the magnetization direction is directed toward the outer peripheral portion 216, so that a plurality of fan-shaped magnets 2111 are combined to form one fan-shaped magnet portion 211. I am trying to configure.

With the configuration described above, the motor 1 rotates the rotation detecting magnet 21 together with the rotating shaft 11 so that the magnetic poles to which the strain-generating portions 22a and 22b are attracted are set to one of the magnetic poles (for example, the N pole). can be maintained, and attraction by the other magnetic pole (for example, the S pole) of the two poles can be suppressed.

In the motor 1 , the magnet portion 211 of the rotation detection magnet 21 is formed in an arc shape around the rotating shaft 11 . In other words, the magnet portion 211 is not arranged in other regions in the rotation detection magnet 21 in the circumferential direction.

According to the motor 1 having such a rotation detection magnet 21, when the rotation detection magnet 21 rotates together with the rotation shaft 11, only when one of the two magnetic poles approaches, the strain-generating portions 22a and 22a are generated. 22b is aspirated. Therefore, according to the motor 1 , the rotational position of the rotating shaft 11 can be detected using the strain sensors 23 a and 23 b arranged at positions facing each other toward the center of the rotating shaft 11 .

A magnet portion 211 of the rotation detecting magnet 21 is formed in an arc shape of 180 degrees or more around the rotating shaft 11 and has an overlapping portion 213 . As a result, the motor 1 can easily combine the waveforms of the strain amounts ε1 and ε2 output by the strain sensors 23a and 23b into one waveform as shown in FIGS. can do. Therefore, according to the motor 1, since a rotation pulse signal of one pulse per rotation can be generated, the rotational position of the rotating shaft 11 of the motor 1 can be easily detected, and appropriate drive control by the motor drive control device 30 can be performed. It can be carried out.

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 magnet 2111 is preferably formed so as to divide the central angle β1 of the rotation detection magnet 21 into four, but the number of divisions is not limited. For example, when the number of magnets 2111 in the rotation detecting magnet 21 is two or three, it can be used by correcting the output waveform on the circuit side.

Further, by comparing the values of the strain amounts ε1 and ε2 output by the plurality of strain sensors 23a and 23b, noise contained in the strain amounts ε1 and ε2 can be canceled or the temperature can be calculated for the strain amounts ε1 and ε2. Compensation processing and the like can be performed.

Further, the magnet cover 212 is not essential in the rotation detection magnet 21 included in the sensor unit 20 . Other forms may be employed as long as they can hold a plurality of magnets 2111 constituting the magnet portion 211 . Furthermore, in the sensor unit 20, the value of the gap between the strain-generating portions 22a and 22b and the rotation detecting magnet 21 is not particularly limited.

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 21... Rotation detection magnet 22a, 22b... Strain-generating portion 23a, 23b Strain sensor 30 Motor drive control device 31 Rotation 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... Rolling element 151... First case part 152... Second case part 153... Bearing housing 154... Stator support part 155a, 155b... Bearing support part 156... Second case Part body 157 Base portion 158 Shaft hole portion 159 Bearing housing accommodating portion 211 Magnet portion 212 Magnet cover 213 Overlap portion 214 Insertion hole 215 Accommodating portion 216 Outer periphery Part 217... Inner peripheral part 221a, 221b... Strain generating part main body 222a, 222b... Support part 223a, 223b... Outer peripheral end part 224a, 224b... Tip part 2111... Magnet

Claims (11)

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 rotation detection magnet rotatably supported by the rotating shaft;
a strain-generating portion provided on the radially outer peripheral side of the rotation detection magnet and generating strain in accordance with a change in magnetic pole due to rotation of the rotation detection magnet;
a strain sensor provided in the strain-generating portion and configured to output 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 strain-generating portion is
a strain-generating portion main body formed so as to extend toward the center from the radially outer peripheral side, 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;
a motor . A plurality of the strain-generating portions are provided,
The strain sensor is provided in each of the strain-generating parts,
A motor according to claim 1. A synthesized signal obtained by synthesizing the strain signals output from each of the plurality of strain sensors corresponds to one rotation of the rotating shaft.
A motor according to claim 2. Two of the strain-generating portions are provided as a set at positions facing each other toward the center of the rotation shaft,
A motor according to claim 2 or 3. The strain sensor is arranged at the outer peripheral end of the strain-generating portion main body,
A motor according to claim 1 . The rotation detection magnet has two poles on a radially outer peripheral portion and a radially inner peripheral portion.
A motor according to any one of claims 1 to 5 . In the rotation detection magnet, one magnetic flux and the other magnetic flux are different at positions facing toward the center of the rotation axis.
A motor according to any one of claims 1 to 6 . The rotation detection magnet is configured by combining a plurality of magnets,
A motor according to any one of claims 1 to 7 . The rotation detection magnet is formed in an arc shape of 180 degrees or more around the rotation axis,
A motor according to any one of claims 1 to 8 . 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 9 ,
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. 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 9 ,
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.