JP2015132496A - Magnetic encoder, electro-mechanical device, mobile object, and robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To structure in a simple configuration a magnetic encoder capable of detection with high resolution and high accuracy.SOLUTION: A magnetic encoder has a magnetic drum and magnetic sensors. The magnetic drum is equipped with a permanent magnet magnetized in parallel to the rotation axis of the magnetic drum and a first drum part and a second drum part so disposed as to hold the permanent magnet between them, of which either the first drum part and the second drum part are magnetized by the permanent magnet respectively to the N pole and the S pole or the first drum part and the second drum part are magnetized by the permanent magnet respectively to the S pole and the N pole. Between the first drum part and the second drum part in the rotating direction of the magnetic drums, a magnetic gap is formed. At least one of the first drum part and the second drum part is given a periodic pole tooth shape in the rotating direction of the magnetic drum to cause the magnetic gap to have a periodic shape. A plurality of magnetic sensors are disposed in a position where the pole tooth shape passes.

Description

  The present invention relates to a magnetic encoder, an electromechanical device, and a robot for detecting a rotation state of a rotating body.

  Conventionally, an encoder has been used as a device for detecting a rotation state such as a rotation angle, a rotation position, a rotation speed, and a rotation speed of a rotating body. As the encoder, an optical encoder, a resolver encoder, a magnetic encoder, and the like are known.

JP-A-1-233319

  Here, the optical encoder is generally capable of high-precision and high-resolution detection, but the rotation state is determined based on the detection unit composed of the optical sensor and the code wheel and the detection result output from the detection unit. The apparatus scale tends to be large because many components such as a required processing unit are required. Therefore, the optical encoder is limited to about 6000 [rpm] due to the limitation of the maximum number of rotations, and cannot be adapted to high speed rotation of 10000 [rpm]. Also, the device cost tends to be high.

  Resolver encoders generally do not require a sensor, are small and have high durability, can be detected with high accuracy and high resolution, and are expected to be lower in price than optical encoders. However, for example, when a resolver encoder is applied to a motor used in a robot, it requires an exciting current to the exciting coil even when the robot is stopped. There is a problem that the lifespan is short.

  Since the resolution of a magnetic encoder is generally determined by the number of multi-pole magnetic poles provided on a magnetic drum, the number of small permanent magnets corresponding to the required accuracy and resolution can be arranged with high accuracy, or Therefore, it is required that the number of magnetizations corresponding to the required accuracy and resolution be executed with high accuracy. For this reason, it is advantageous in terms of downsizing and cost reduction, but it is disadvantageous in realizing a configuration capable of detecting a rotational state with high accuracy and high resolution.

  In the magnetic encoder described in Patent Document 1, one permanent magnet arranged on the rotation shaft of the gear applies a magnetic field to the entire gear, and the magnetic field is periodically synchronized with the unevenness in the vicinity of the magnetic pole teeth. The periodic change of the magnetic field is detected by the magnetic sensing unit and output as a waveform like a sine wave (hereinafter also referred to as “sine wave-like waveform”). In the case of this magnetic encoder, the structure is simplified in that only one permanent magnet is used. However, all teeth of the gear are magnetized to the same magnetic pole (for example, S pole), and a magnetic field is generated between this tooth and the other pole (for example, N pole) of the permanent magnet. There is a bias in the distribution of the magnetic field generated between the two. For this reason, the sine wave-like waveform detected and output by the magnetic sensing unit is considered to contain a large amount of distortion, and the detection waveform by the magnetic sensing unit is not effective in detecting the rotational position with high accuracy and high resolution. It is enough.

  Therefore, a technology that can construct a magnetic encoder capable of detecting a rotational position with high resolution and high accuracy with a simple configuration has been desired.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms.

(1) According to one aspect of the present invention, a magnetic encoder having a magnetic drum and a magnetic sensor is provided. The magnetic drum includes a permanent magnet magnetized parallel to the rotation axis of the magnetic drum; a first drum portion and a second drum portion provided so as to sandwich the permanent magnet; The first drum portion magnetized to the north pole and the second drum portion magnetized to the south pole, or the first drum portion and the north pole magnetized to the south pole by the permanent magnet. And a second drum portion. A magnetic gap is formed between the first drum portion and the second drum portion in the rotational direction of the magnetic drum; at least one of the first drum portion and the second drum portion Has a periodic pole tooth shape in the rotation direction of the magnetic drum, so that the magnetic gap shape is formed with a period; a plurality of the magnetic sensors are provided at positions through which the pole tooth shape passes. It has been. According to the magnetic encoder of this embodiment, at least one of the first drum portion and the second drum portion has a periodic pole tooth shape in the rotation direction of the magnetic drum, so that the shape of the magnetic gap is periodic. Therefore, a magnetic encoder capable of detecting the rotational position with high resolution and high accuracy can be constructed with a simple configuration.

(2) The magnetic encoder of the above aspect has N pole pole teeth on the first drum portion and S pole pole teeth on the second drum portion on the cylindrical outer peripheral surface of the magnetic drum. Alternatively, the first drum portion may have S-pole pole teeth and the second drum portion may have N-pole pole teeth. According to this magnetic encoder, at least one of the first drum portion and the second drum portion is periodic in the rotation direction of the magnetic drum along the cylindrical outer peripheral surface corresponding to the rotation direction of the magnetic drum. Since the shape of the magnetic gap is formed with a period, the magnetic encoder capable of detecting the rotational position with high resolution and high accuracy can be constructed with a simple configuration. Can do.

(3) In the magnetic encoder of the above aspect, the magnetic drum includes a disk-shaped first drum portion perpendicular to the rotation axis and a ring-shaped second drum disposed on the outer periphery of the first drum portion. A drum portion, and in a plane of the first drum portion and the second drum portion, the magnetic drum may have a periodic pole-tooth shape in the rotation direction. Also with this magnetic encoder, in the plane of the first drum portion and the second drum portion, at least one of the first drum portion and the second drum portion has a periodic pole in the rotation direction of the magnetic drum. Since the shape of the magnetic gap is formed with a period by having the tooth shape, a magnetic encoder capable of detecting the rotational position with high resolution and high accuracy can be constructed with a simple configuration. .

(4) In the magnetic encoder of the above aspect, the periodic pole tooth shape is a waveform in which the waveform of the magnetic change detected by the magnetic sensor changes periodically according to the electrical angle in the circumferential direction. Thus, it is preferable to have an outer shape having a waveform that changes symmetrically with respect to the center value between the maximum value and the minimum value without having a flat portion. According to the magnetic encoder of this embodiment, the waveform detected by the magnetic sensor can obtain the corresponding electrical angle with high resolution and high accuracy based on the waveform of the magnetic change detected by the magnetic sensor. Thus, the rotational position of the rotating body can be obtained with high resolution and high accuracy from the obtained electrical angle.

(5) In the magnetic encoder of the above aspect, the magnetic sensor is mounted on a circuit board, and a signal processing circuit for processing a signal output from the magnetic sensor is further mounted on the circuit board. Preferably it is. According to the magnetic encoder of this embodiment, since the transmission path of the output signal of the magnetic sensor is shortened compared to the case where the sensor signal output from the magnetic sensor is output to an external signal processing circuit, the influence of noise or the like is reduced. It is possible to detect the rotation angle with high accuracy by reducing.

(6) According to another aspect of the present invention, an electromechanical device having a rotating shaft is provided. This electromechanical device includes the magnetic encoder of the above-described form that detects the rotation state of the rotating shaft. According to the electromechanical device of this aspect, the rotation state of the electromechanical device can be detected with high resolution and high accuracy. In addition, the rotational operation of the electromechanical device can be controlled with high accuracy based on the detected rotational state.

  The present invention can be realized in various forms. For example, in addition to an electric machine device including a magnetic encoder and a magnetic encoder, an electric mobile body, an electric mobile robot, or a medical device using the electric machine device. It can be realized in various forms such as a device.

It is explanatory drawing which shows schematic structure of the magnetic encoder as 1st Embodiment. It is a disassembled perspective view which shows the structural example of a magnetic drum. It is explanatory drawing which expanded and showed a part of magnetic drum seen from the side by which a magnetic sensor is arrange | positioned. It is explanatory drawing which shows the example of housing arrangement | positioning of a magnetic encoder. It is explanatory drawing which shows the example of a connection of a magnetic encoder and the rotary body which is a measuring object. It is explanatory drawing shown about the rotation angle detected by the magnetic encoder of 1st Embodiment. It is explanatory drawing shown about the magnetic sensor mounted on the circuit board. It is explanatory drawing which shows the modification of a connection with a magnetic encoder and the rotary body which is a measuring object. It is explanatory drawing which shows the modification of the structure of the magnetic pole tooth comprised on the outer peripheral surface of a magnetic drum. It is explanatory drawing which shows schematic structure of the magnetic encoder as 2nd Embodiment. It is explanatory drawing shown about the rotation angle detected by the magnetic encoder of 2nd Embodiment. It is explanatory drawing which shows schematic structure of the magnetic encoder as 3rd Embodiment. It is a disassembled perspective view which shows the structural example of a magnetic drum. It is explanatory drawing which shows schematic structure of the magnetic encoder as 4th Embodiment. It is explanatory drawing which shows the A phase sensor signal output from an A phase sensor in the magnetic encoder of FIG. It is explanatory drawing which shows schematic structure of the magnetic encoder as 5th Embodiment. It is explanatory drawing which shows the A phase sensor signal output from an A phase sensor in the magnetic encoder of FIG. It is explanatory drawing which shows the electric bicycle (electric assisted bicycle) which is an example of a moving body. It is explanatory drawing which shows an example of a robot. It is explanatory drawing which shows an example of a double-arm 7-axis robot. It is explanatory drawing which shows an example of a vertical articulated robot. It is explanatory drawing which shows an example of the robot with a double arm caster. It is explanatory drawing which shows a railway vehicle.

A. First embodiment:
FIG. 1 is an explanatory diagram showing a schematic configuration of a magnetic encoder as a first embodiment. The magnetic encoder 10 includes a detection unit 20 including a magnetic drum 21, two magnetic sensors 28A and 28B, and a reference position sensor 27, and a signal processing unit 30 including a signal processing circuit 31 and a connector 32. . FIG. 1 shows a schematic perspective view of the magnetic drum 21 of the magnetic encoder 10 viewed from an oblique direction.

  The magnetic drum 21 of the detection unit 20 has a substantially cylindrical outer shape composed of two drum portions 210 and 220, and has a disk-like side surface portion 22 centered on the central axis Jr and perpendicular to the central axis Jr. , 23, a cylindrical outer peripheral surface portion 24 centered on the central axis line Jr, and a shaft 26 fixed to the side surface portions 22, 23 about the central axis line Jr.

  In FIG. 1, for convenience of illustration, a virtual outer peripheral center line Jc passing through the center of the outer peripheral surface portion 24 in the width direction is drawn over the entire periphery of the outer peripheral surface portion 24.

  The magnetic drum 21 rotates integrally with the rotating body by connecting and fixing the shaft 26 to the shaft of a rotating body such as a motor to be measured. In this example, when the rotating body to be measured to be connected is viewed from the magnetic drum side, the rotation corresponding to the clockwise rotation of the rotating body is defined as the positive rotation of the magnetic drum and the counterclockwise rotation of the rotating body. The rotation is defined as the reverse rotation of the magnetic drum.

  FIG. 2 is an exploded perspective view showing a structural example of a magnetic drum. The magnetic drum 21 includes two drum portions 210 and 220 and a permanent magnet portion 230. The permanent magnet unit 230 includes a cylindrical permanent magnet 231 centered on the central axis Jr, and a shaft 232 fixed to the permanent magnet about the central axis Jr. The permanent magnet 231 is magnetized along the direction of the central axis Jr, and is divided into an N pole portion 231N and an S pole portion 231.

  The first drum portion 210 is a magnetic body formed of a soft magnetic material (iron material, steel plate material, etc.), and a disk portion 211 (on the side surface portion 22 in FIG. 1) that is centered on the central axis line Jr and perpendicular to the central axis line Jr. And a plurality of teeth 213 formed on the outer peripheral end of the disk portion 211 toward the N pole portion 231N side of the permanent magnet 231 along a virtual cylindrical surface centered on the central axis Jr. Is done. A shaft hole 212 through which the shaft 232 of the permanent magnet part 230 passes is formed in the disk part 211 with the center axis line Jr as the center, and a reference position for rotation is located at a predetermined distance from the center of the disk part 211. A reference hole 214 is formed. This distance is larger than the radius of the permanent magnet 231.

  The second drum portion 220 is also a magnetic body similar to the first drum portion 210, and includes a disk portion 221 (corresponding to the side surface portion 23 in FIG. 1) centered on the central axis line Jr and perpendicular to the central axis line Jr. A plurality of teeth 223 formed on the outer peripheral end of the portion 221 toward the S pole portion 231 </ b> S side of the permanent magnet 231 along a virtual cylindrical surface centered on the central axis Jr. A shaft hole 222 and a reference hole 224 are formed in the disk part 221, similarly to the disk part 211.

  The magnetic drum 21 is formed by bonding the two drum portions 210 and 220 to the permanent magnet portion 230.

  The plurality of teeth 213 of the first drum portion 210 become N pole teeth 25N (see FIG. 1) having N poles by the N pole portion 231N. Further, the plurality of teeth 223 of the second drum portion 220 become S pole teeth 25S (see FIG. 1) having S poles by the S poles 231S. Thereby, the outer peripheral surface part 24 in which the plurality of N pole teeth 25N and the plurality of S pole teeth 25S are alternately arranged via the gap along the outer periphery center line Jc is configured. This example shows a case where a magnetic pole of 24 pole pairs is formed on the outer peripheral surface portion 24 by 24 poles of N pole teeth 25N and 24 poles of S pole teeth 25S. Further, the shaft 232 of the permanent magnet unit 230 becomes the shaft 26 of the magnetic drum 21 (see FIG. 1).

  Note that by applying an adhesive (not shown) to the side surfaces 233 and 234 of the permanent magnet 231 in advance, the drum portions 210 and 220 are bonded and fixed to the side surfaces 233 and 234 of the permanent magnet 231 to which they are attracted. The shaft 232 can be rotated together with the rotation.

  The two magnetic pole sensors 28A and 28B in FIG. 1 are arranged at different positions on the circumference that is concentric with the outer peripheral center line Jc, in the vicinity of the outer sides of the N pole teeth 25N and 25S alternately arranged along the outer peripheral center line Jc. Has been. In the example of FIG. 1, one magnetic sensor 28A is disposed on a vertical line Jv that extends vertically downward from the center point (center point of the magnetic drum 21) C of the outer peripheral center line Jc, and the other magnetic sensor 28A. As will be described later, the sensor 28B is disposed so as to be shifted from the one magnetic sensor 28A along the outer peripheral center line Jc. The magnetic sensors 28A and 28B detect a magnetic change generated according to the rotation of the magnetic drum 21 and output it as a magnetic sensor signal. As the magnetic sensors 28A and 28B, for example, a magnetic sensor IC including a Hall element and an automatic variable gain (AGC) amplifier circuit and having a temperature compensation function is used. The output waveform output from the magnetic sensor IC is adjusted to have a predetermined output amplitude by the AGC amplifier circuit so that the magnetic change detected by the Hall element is not saturated.

  The reference position sensor 27 includes a light projecting portion 27C disposed on the side surface portion 22 (corresponding to the disc portion 221 in FIG. 2) of the magnetic drum 21, and a side surface portion 23 (corresponding to the disc portion 211 in FIG. 2). ) Side light receiving portion 27R. A light emitting diode such as an LED is used as the light projecting unit 27C. A photodiode that senses the presence or absence of light is used as the light receiving unit 27R. The reference position sensor 27 detects the light passing through the reference holes 23h and 22h provided in the side surface portions 23 and 22 by the light receiving portion 27R, thereby making one rotation of the magnetic drum 21. Detect the reference position.

  FIG. 3 is an explanatory view showing a part of the magnetic drum enlarged in a plan view as seen from the side where the magnetic sensor is arranged. As described above, the N pole teeth 25N and the S pole teeth 25S are alternately arranged on the outer peripheral surface portion 24 of the magnetic drum 21 along the outer peripheral center line Jc via the gap. The N pole tooth 25N and the S pole tooth 25S have a trapezoidal shape, and the S pole tooth 25S is arranged in a trapezoidal recess between the N pole tooth 25N and the N pole tooth 25N. N pole teeth 25N are arranged in a trapezoidal recess between the pole teeth 25S. The gap g1 between the upper base of the N pole tooth 25N and the bottom of the recess between the corresponding two S pole teeth 25S, and between the two N pole teeth 25N corresponding to the upper base of the S pole tooth 25S The gap g3 between the bottom of the recess is larger than the gap g2 between the hypotenuse of the N pole tooth 25N and the hypotenuse of the S pole tooth 25S so that the magnetic flux generated in the gaps g1 and g3 is suppressed as much as possible. Is set.

  A position connecting the light projecting portion 27C on the side surface portion 23 side and the light receiving portion 27R on the side surface portion 22 side is set as a reference position Rc for detection of one rotation of the magnetic drum 21. The rotation of the magnetic drum 21 causes the reference hole 22h of the side surface portion 22 and the reference hole 23h of the side surface portion 23 to reach the reference position Rc, whereby one rotation of the magnetic drum 21 is detected.

  One magnetic sensor 28A is arranged vertically below the reference position Rc (upward in FIG. 3) on the outer periphery of the outer peripheral center line Jc, and the other magnetic sensor 28B is determined by the width of a pair of N pole and S pole. With respect to the phase (referred to as “electrical angle”) 2π [rad], the phase π / 2 [rad] in the positive rotation direction along the outer circumference center line Jc direction from the one magnetic sensor 28A to the outer circumference center line Jc. It is arranged at a position shifted by only. In the following, one magnetic sensor 28A is also referred to as “A-phase sensor 28A” and the other magnetic sensor 28B is also referred to as “B-phase sensor 28B”.

  The signal processing circuit 31 of the signal processing unit 30 in FIG. 1 rotates based on the reference position signal from the reference position sensor 27, the A phase sensor signal from the A phase sensor 28A, and the B phase sensor signal from the B phase sensor 28. The angle (rotation position) is detected and output to an external control circuit via the connector 32.

  FIG. 4 is an explanatory diagram showing an example of housing arrangement of the magnetic encoder. 4A shows a schematic side view of the magnetic encoder 10 housed in the housing 40 as seen through from the outside, and FIG. 4B is a cross-sectional view taken along the line AA in FIG. A schematic cross-section taken along the line is schematically shown. The magnetic encoder 10 is housed in a cylindrical housing 40, and the shaft 26 is supported to be rotatable with respect to the housing 40 via bearings 51 and 52. A circuit board 60 is arranged on the bottom bottom inside the cylindrical surface of the housing 40. On the circuit board 60, two magnetic sensors 28A and 28B, a signal processing circuit 31 (not shown), and a connector 32 are provided. Has been implemented. A circuit board 61 on which the light projecting portion 27C of the reference position sensor 27 is mounted is fixedly arranged inside the side surface of the housing 40 facing the side surface portion 23 of the magnetic drum 21, and the side surface portion 22 of the magnetic drum 21. A circuit board 62 on which the light receiving portion 27R of the reference position sensor 27 is mounted is fixedly arranged on the inner side of the side surface of the housing 40 facing the housing. As described above, the magnetic encoder 10 can be accommodated in the housing 40. However, this arrangement example is merely an example, and the structure of the casing and the storage arrangement structure are not particularly limited as long as the magnetic encoder 10 can be accommodated in the casing.

  FIG. 5 is an explanatory diagram showing an example of connection between a magnetic encoder and a rotating body to be measured. FIG. 5 shows a motor 70 as an example of the rotating body. The magnetic encoder 10 can be connected to the motor 70 by fixing the shaft 26 to the shaft 72 of the motor 70 via the coupling 80. Thereby, the rotation angle of the motor 70 can be detected by the magnetic encoder 10, and the rotation state of the motor 70 can be controlled.

  FIG. 6 is an explanatory diagram showing the rotation angle detected by the magnetic encoder of this embodiment. The reference position sensor 27 outputs, as the reference position signal Vc, a pulse-like periodic signal indicating the reference position of rotation every time the magnetic drum 21 makes one rotation (the rotation angle φ changes from 0 to 2π [rad]). . In the A-phase sensor 28A, as the A-phase sensor signal Vsa, a sine wave (sin θ) -like signal (hereinafter referred to as a “sine wave signal”) that periodically changes every time the electrical angle θ advances by 2π [rad] with respect to the reference position. Is also output). On the other hand, in the B-phase sensor 28B, as the B-phase sensor signal Vsb, a cosine wave (cos θ) -like signal (hereinafter referred to as “cosine”) that periodically changes every time the electrical angle θ advances by 2π [rad] with respect to the reference position. Also called “wave signal”).

  Here, when the number of pole pairs of N pole and S pole is Pm, while the rotation angle (also referred to as “mechanical angle”) φ changes from 0 to 2π [rad], that is, the magnetic drum 21 rotates once ( While the rotating body to be measured integrally connected with the magnetic drum 21 makes one revolution), the electrical angle θ repeats 0 to 2π [rad] (periodic change) Pm times. In the case of Pm = 24 as in this example, while the magnetic drum 21 makes one rotation, the electrical angle θ repeats the period change of 0 to 2π [rad] 12 times, and 12 periods as the A-phase sensor signal Vsa. Sine wave signal is generated, and a 12-period cosine wave signal is generated as the B-phase sensor signal Vsb. Therefore, the number of sections (hereinafter also referred to as “the number of electrical angles”) indicating which section of the rotation angle φ is divided by φs = 2π / (Pm / 2) is represented by Pn (Pn is the number of electrical angles). 0 to (Pm / 2) -1), the rotation angle φ is represented by φ = (Pn + θ / 2π) · φs. As in this example, when Pm = 24, φs is π / 6, the rotation angle φ is represented by (Pn + θ / 2π) · (π / 6), and the electrical angle number Pn is an electrical angle θ located at 3. If there is, the rotation angle φ is represented by (3 + θ / 2π) · (π / 6). Therefore, the rotation angle φ can be obtained by obtaining the electrical angle number Pn and the electrical angle θ.

The electrical angle θ can be obtained based on the A-phase sensor signal Vsa and the B-phase sensor signal Vsb. For example, the electrical angle θ can be obtained from the arc tangent (tan ⁻¹ (Vsa / Vsb)) of the A phase sensor signal Vsa and the B phase sensor signal Vsb. Further, the electrical angle number Pn can be obtained by counting the number of periodic changes of the electrical angle θ from the reference position.

Further, the A-phase sensor signal Vsa shown in FIG. 6 indicates the case of normal rotation. In the case of reverse rotation, a sine wave signal (sin (θ + π)) having a phase shift of π [rad] is obtained. Therefore, based on the phase relationship between the A-phase sensor signal waveform Vsa and the B-phase sensor signal Vsb, it can be distinguished whether the rotation direction is forward rotation or reverse rotation. In addition, the electrical angle θ in the case of reverse rotation can be obtained from the inverse tangent (tan ⁻¹ (−Vsa / Vsb) of the signal −Vsa obtained by inverting the sign of the A phase sensor signal Vsa and the B phase sensor signal Vsb. .

  Further, the rotational speed Prq can be obtained by counting the number of periodic signals generated in the reference position signal Vc. For example, when applied as an encoder for a motor that drives the arm of a robot, the movement of the arm can be recognized based on the rotation speed Prq and the rotation angle φ of the motor from the reference state to control the movement of the arm. .

  As described above, in the magnetic encoder 10 of the present embodiment, the waveform detected and output by the magnetic sensors 28A and 28B is a sine wave waveform and a cosine wave waveform that periodically change according to the electrical angle. Therefore, the rotation angle (rotation position) can be detected with high resolution and high accuracy.

  FIG. 7 is an explanatory diagram showing the magnetic pole sensor 28 </ b> A mounted on the circuit board 60. In the present embodiment, as described above, a surface mount type magnetic sensor IC is used as the magnetic sensor 28A. The magnetic sensor 28A has three mounting terminals 65 (a power supply terminal, a ground terminal, and an output signal terminal). As the surface mount type magnetic sensor IC, a SOP (Small Outline Package) type in which the mounting terminal 65 is flat, or a SOJ (Small Outline J-leaded) type magnetic sensor IC in which the mounting terminal 65 is bent into a J-shape is used. Can be adopted. The circuit board 60 includes a conductor pattern 63 for mounting a mounting terminal of the magnetic pole sensor 28A.

  The magnetic sensor 28A can be mounted on the circuit board 60 as follows. First, the solder 64 is disposed on the conductor pattern 63 of the circuit board 60 by printing. Next, the magnetic sensor 28 </ b> A is disposed on the circuit board 60 and the mounting terminal 65 of the magnetic sensor 28 </ b> A is in contact with the conductor pattern 63. At this stage, the circuit board 60 and the magnetic sensor 28A are not mounted by solder. The mounting terminals 65 of the magnetic sensor 28A are preferably pre-soldered. Next, the circuit board 60 on which the magnetic sensor 28A is placed is heated by passing through a reflow furnace. Thereby, the solder 64 is melted, and the conductor pattern 63 and the mounting terminal 65 of the magnetic sensor 28 </ b> A are mounted by the solder 64. Note that the magnetic sensitivity characteristics of the magnetic sensor 28A can be changed by moving the magnetic sensor 28A vertically and horizontally relative to the conductor pattern 63 to set the position. The same applies to the magnetic sensor 28B. Thereby, it is possible to improve the symmetry of the waveform of the magnetic change detected from the magnetic sensors 28A and 28B, to suppress the distortion of the waveform, and the like. The detected waveform of the first magnetic sensor 28A and the second magnetic sensor 28B It is possible to adjust the phase difference from the detected waveform.

  FIG. 8 is an explanatory view showing a modification of the connection between the magnetic encoder and the rotating body to be measured. In the example of FIG. 8A, the shaft 72 of the rotating body is connected and fixed to the shaft 26 of the magnetic encoder 10 as follows. The shaft 26 of the magnetic encoder 10 is provided with a holder structure 74 for inserting and fixing the shaft 72 of the rotating body. The holder structure 74 includes a holder portion 74a into which the shaft 72 is inserted and a fastening member 74b provided on the outer periphery of the holder portion 74a along the axial direction of the shaft 26. The shaft 72 is connected and fixed to the shaft 26 by tightening the shaft 72 inserted into the holder portion 74a from the outside of the holder portion 74a by the fastening member 74b. Thereby, the shaft 72 of the rotating body is connected and fixed to the shaft 26 of the magnetic encoder 10.

  In the example of FIG. 8B, the shaft 72 of the rotating body is connected and fixed to the shaft 26 of the magnetic encoder 10 as follows. At the center of the shaft 72 of the rotating body, a spacer 72S into which the shaft 26 is inserted and a screw hole 72h are cut along the axial direction. A screw hole 26h is cut in the center of the shaft 26 of the magnetic encoder 10 along the axial direction. The shaft 72 of the rotating body is inserted along the axial direction so that the shaft 26 is accommodated in the spacer 72S of the shaft 72 of the rotating body. The shaft 26 and the shaft 72 are connected and fixed by turning the fixing screw 78 through the hole 42 of the housing for inserting the fixing screw 78 into the screw hole 26h and the screw hole 72h. Thereby, the shaft 72 of the rotating body is connected and fixed to the shaft 26 of the magnetic encoder 10. A heat insulating material 76 is inserted between the motor 70 and the magnetic encoder 10, and an air layer 79 is formed between the drive shaft 72 of the motor 70 and the casing 40 of the magnetic encoder 10. Has been. It is possible to suppress the heat generated by the motor 70 from being transmitted to the magnetic encoder 10, and it is possible to suppress the transfer of heat to the circuit board 60.

  8A and 8B, as in the case of using the coupling 80 shown in the above embodiment (FIG. 5), the rotating body shaft 72 and the magnetic encoder are used. 10 shafts 26 can be connected and fixed, and the rotation angle (rotation position) corresponding to the rotation of the rotating body can be detected by the magnetic encoder 10. Note that the connection between the shaft 26 of the magnetic encoder 10 and the shaft 72 of the rotating body is performed by the connection by the coupling 80 in FIG. 5, the connection by the holder structure 74 in FIG. 8A, and the fixing in FIG. 8B. The connection by the screw 72 is not limited, and various general connection fixing structures can be applied.

  FIG. 9 is an explanatory view showing a modification of the structure of the magnetic pole teeth formed on the outer peripheral surface of the magnetic drum. The N pole teeth 25N and the S pole teeth 25S of the magnetic drum 21 shown in FIG. 3 have a substantially trapezoidal shape. However, as shown in FIG. 9, the rectangular N pole teeth 25Nm and the rectangular S teeth are formed. The pole teeth 25Sm may be configured such that the N pole teeth 25Nm and the S pole teeth 25Sm are alternately arranged along the direction of the outer periphery center line Jc only in a region near the outer periphery center line Jc. In this structure, the gap g1 between the tip of the N pole tooth 25Nm and the corresponding bottom portion of the S pole side recess, and the gap between the tip of the S pole tooth 25Sm and the corresponding bottom portion of the N pole side recess. g3 can be made very large, and the magnetic flux generated between these gaps can be greatly suppressed. In addition, the magnetic sensors 28A and 28B can detect magnetic changes generated by the portion of the N pole tooth 25Nm and the portion of the S pole tooth 25Sm arranged in the vicinity of the outer periphery center line Jc in the direction of the outer periphery center line Jc. The accuracy of detecting magnetic changes can be increased.

  The structure of the pole teeth is not limited to the structure shown in FIG. 2 and the structure shown in FIG. 9, and may be various shapes such as a sine wave shape and a triangular shape, and is detected by a magnetic sensor. The output waveform is a waveform that changes periodically according to the electrical angle in the direction of the outer circumference center line, such as a sine wave or a triangular wave, and has no flat part in the waveform. It is preferable that the outer shape has a waveform that changes symmetrically with respect to the center value between the minimum value and the minimum value. Moreover, it is more preferable that the outer shape is such that the absolute value of the rate of change between the electrodes has a constant waveform.

  As described above, in the magnetic encoder of the present embodiment, the waveform detected and output by the magnetic sensor is a waveform that periodically changes according to the electrical angle in the direction of the outer periphery centerline, Simplified magnetic drum composed of multi-pole pairs of pole teeth with an external shape that does not have a flat part and has a waveform that changes symmetrically with respect to the center value between the maximum and minimum values The rotation angle (rotation position) can be detected with high resolution and high accuracy. Since the number of poles of the magnetic drum can be determined by the number of teeth of the drum part, a magnetic drum having any number of poles can be configured easily and with high accuracy, and the number of poles can be designed arbitrarily. High design freedom. Further, by adjusting the shape of the pole teeth, the output waveform detected by the magnetic sensor can show a highly accurate value according to the electrical angle, and the degree of freedom in design is high. In addition, since a plurality of permanent magnets are not used and a plurality of poles are not magnetized, the manufacturing is easy and it can be realized at a low price. Since only one permanent magnet is used, a ferrite magnet can be used, it can be used at a high temperature, and can be constructed at low cost.

B. Second embodiment:
FIG. 10 is an explanatory diagram showing a schematic configuration of a magnetic encoder as the second embodiment. FIG. 10A shows a schematic configuration in which the magnetic drum 21B and the magnetic sensors 28A and 28B of the magnetic encoder 10B are viewed from an oblique direction, and FIG. 10B is an exploded view of the outer peripheral surface 24B of the magnetic drum 21B. Show.

  The magnetic drum 21 of the magnetic encoder 10 of the first embodiment has a structure (see FIG. 1) in which a plurality of pole pairs of N pole teeth 25N and S pole teeth 25S are formed on the outer peripheral surface portion 24. The magnetic drum 21B of the magnetic encoder 10B of this embodiment has a structure in which one pole pair of N pole teeth 25NB and S pole teeth 25SB is formed on the outer peripheral surface portion 24B. As for the shapes of the N pole tooth 25NB and the S pole tooth 25SB, the respective tip shapes arranged via the gap g are sinusoidal around the outer peripheral center line Jc. In the case of this configuration, the rotation angle φ of the magnetic drum 21B is equal to the electrical angle θ. The magnetic sensors 28A and 28B are arranged in the same manner as in the first embodiment, with one magnetic sensor (A-phase sensor) 28A and the other magnetic sensor (B-phase sensor) 28B extending along the outer peripheral center line Jc. Thus, they are arranged at positions shifted by a phase π / 2 [rad] of the electrical angle in the positive rotation direction.

  FIG. 11 is an explanatory diagram showing the rotation angle detected by the magnetic encoder of this embodiment. Similar to the magnetic encoder 10 of the first embodiment, the A-phase sensor 28A outputs a sine wave signal of one cycle every time the electrical angle θ advances by 2π [rad] as the A-phase sensor signal Vsa, and the B-phase sensor 28B. Then, every time the electrical angle θ advances by 2π [rad] as the B-phase sensor signal Vsb, a cosine wave signal of one cycle is output.

As described above, in this embodiment, the rotation angle (rotation position) φ is equal to the electrical angle θ, and therefore the rotation angle φ can be obtained by obtaining the electrical angle θ. As described in the first embodiment, the electrical angle θ can be obtained by the arc tangent (tan ⁻¹ (Vsa / Vsb)) of the A-phase sensor signal Vsa and the B-phase sensor signal Vsb.

  As described above, the structure of the pair of pole teeth in the present embodiment has been described by taking the case where the tip shape of each pole tooth arranged via the gap is a sine wave as an example. It may have various shapes such as a triangular shape, and the waveform detected and output by the magnetic sensor is a waveform that periodically changes according to the electrical angle in the direction of the outer peripheral center line, such as a sine wave or a triangular wave. It is preferable to have an outer shape that does not have a flat portion in the waveform but has a waveform that changes symmetrically with respect to the center value between the maximum value and the minimum value. Moreover, it is more preferable that the outer shape has a waveform with a constant absolute value of the change rate.

  Also in the magnetic encoder of the present embodiment, the waveform detected and output by the magnetic sensor is a waveform that periodically changes according to the electrical angle in the outer peripheral center line direction, and has a flat portion in the waveform. In addition, it is possible to easily configure a magnetic drum composed of a single pole pair of pole teeth having an outer shape that has a waveform that changes symmetrically with respect to the center value between the maximum value and the minimum value. It is possible to detect the rotation angle (rotation position) with high resolution and high accuracy. Further, by adjusting the shape of the pole teeth, the output waveform detected by the magnetic sensor can show a highly accurate value according to the electrical angle, and the degree of freedom in design is high. Since only one permanent magnet is used, a ferrite magnet can be used, it can be used at a high temperature, and can be constructed at low cost.

C. Third embodiment:
FIG. 12 is an explanatory diagram showing a schematic configuration of a magnetic encoder as the third embodiment. FIG. 12A shows a schematic front view of the magnetic encoder 21C of the magnetic encoder 10C as seen from the front, and FIG. 12B shows a schematic side view of the magnetic encoder 10C as seen from the side.

  The magnetic drum 21 of the magnetic encoder 10 of the first embodiment has a structure (see FIG. 1) in which a plurality of pole pairs of N pole teeth 25N and S pole teeth 25S are formed on the outer peripheral surface portion 24. The magnetic drum 21C of the magnetic encoder 10C of the present embodiment has a plurality of pole pairs of N pole teeth 25N and S pole teeth 25S on the side surface portion 22C along a virtual circumferential center line Jcc centered on the center axis Jr. The structure is formed. The magnetic sensors 28A and 28B are mounted on a circuit board 60C fixedly disposed facing the side surface portion 22C on a circumference that is concentric with the circumference center line Jc. The signal processing circuit 31 and the connector 32 are also mounted on the circuit board 60C. A through hole is provided at the center of the circuit board 60 </ b> C so that the shaft 26 of the magnetic drum 21 </ b> C can rotate regardless of the circuit board 60.

  FIG. 13 is an exploded perspective view showing a structural example of a magnetic drum. The magnetic drum 21 </ b> C includes three drum portions 210 </ b> C, 220 </ b> Ca, 220 </ b> Cb and a permanent magnet unit 230.

  The third drum portion 220Ca is a magnetic body formed of a soft magnetic material (iron material, steel plate material, or the like), and has a disk portion 221C that is centered on the central axis Jr and perpendicular to the central axis Jr, and an outer peripheral end of the disk portion 221C. And a cylindrical portion 223C centered on the central axis Jr. A shaft hole 222C through which the shaft 232 of the permanent magnet unit 230 passes is formed in the disk unit 221C.

  The first drum portion 210C is also a magnetic body similar to the third drum portion 220Ca, and has a substantially disk shape centered on the central axis Jr. A plurality of teeth 213N are formed on the outer periphery of the first drum portion 210C, and a shaft hole 212C is formed at the center similarly to the disk portion 221C of the drum portion 220Ca. The second drum portion 220Cb is also a magnetic body similar to the third drum portion 220Ca, and has a space corresponding to the outer shape of the substantially disc-shaped first drum portion 210C with the central axis Jr as the center. It has a ring shape. A plurality of teeth 223S are formed on the inner periphery of the second drum portion 220Cb. The recesses between the teeth 223S of the second drum portion 220Cb correspond to the teeth 213N of the first drum portion 210C, and the recesses between the teeth 213N of the first drum portion 210C correspond to the second drum portion 220Cb. Corresponds to each tooth 223S.

  The magnetic drum 21 </ b> C is formed by bonding the three drum portions 210 </ b> C, 220 </ b> Ca, 220 </ b> Cb and the permanent magnet unit 230. The third drum portion 220Ca is attracted and fixed to the S pole portion 231S of the permanent magnet 231 and the second drum portion 220Cb is attracted and fixed to the cylindrical portion 223C of the third drum portion 220Ca. Further, the first drum portion 210C is attracted and fixed to the N pole portion 231N of the permanent magnet 231.

  The drum portions 210C and 220Ca are applied to the side surfaces 233 and 234 of the permanent magnet 231 and the side surface 224C of the cylindrical portion 223C in advance so that the drum portions 210C and 220Ca have the side surfaces 233 and 234 of the permanent magnet 231. Further, the second drum portion 220Cb is bonded and fixed to the side surface 224C of the cylindrical portion 223C of the third drum portion 220Ca, and can be rotated integrally with the rotation of the shaft 232.

  The plurality of teeth 213N of the first drum portion 210C become N pole teeth 25NC (see FIG. 12) having N pole magnetic poles due to the N pole portion 231N. The plurality of teeth 223S of the second drum portion 220Cb become S pole teeth 25SC (see FIG. 12) having S poles by the S pole portion 231S. As a result, a side surface portion 22C having side surfaces in which a plurality of N pole teeth 25NC and a plurality of S pole teeth 25SC are alternately arranged via a gap along the circumferential center line Jcc is configured. In this example, 12 pole pairs of magnetic poles are formed on the side surface portion 22C by 12 poles of N pole teeth 25NC and 12 poles of S pole teeth 25SC. Further, the shaft 232 of the permanent magnet unit 230 becomes the shaft 26 (see FIG. 12) of the magnetic drum 21C.

  The first drum portion 210C is attracted and fixed to the S pole portion 231S of the permanent magnet 231, and the third drum portion 220Ca and the second drum portion 220Cb are attracted and fixed to the N pole portion 231N so that the polarity is reversed. Also good.

  The rotation angle detection operation in the magnetic encoder 10C of this embodiment is the same as the detection operation of the first embodiment shown in FIG. 6, and the waveform detected and output by the magnetic sensors 28A and 28B is an electrical angle. Accordingly, the rotation angle (rotation position) can be detected with high resolution and high accuracy because the waveform is a sinusoidal waveform and a cosine waveform that periodically change.

  Also in this embodiment, the pole tooth structure may have various shapes such as a sinusoidal shape and a triangular shape as described in the first embodiment, and the waveform detected and output by the magnetic sensor A waveform that changes periodically according to the electrical angle in the direction of the outer circumference center line, such as a sine wave or a triangular wave, and has a flat portion in the waveform, and the center between the maximum value and the minimum value It is preferable that the outer shape has a waveform that changes symmetrically with respect to the value. Moreover, it is more preferable that the outer shape has a waveform with a constant absolute value of the change rate.

  As described above, also in the magnetic encoder of the present embodiment, the waveform detected and output by the magnetic sensor is the electric in the circumferential center line direction (corresponding to the outer circumferential center line direction of the first and second embodiments). A waveform that changes periodically according to the angle, and that does not have a flat portion in the waveform, but has a waveform that changes symmetrically with respect to the center value between the maximum and minimum values. A magnetic drum composed of pole teeth of a multipole pair having a shape can be easily configured, and a rotation angle (rotation position) can be detected with high resolution and high accuracy. Since the number of poles of the magnetic drum can be determined by the number of teeth of the drum part, a magnetic drum having any number of poles can be configured easily and with high accuracy, and the number of poles can be designed arbitrarily. High design freedom. Further, by adjusting the shape of the pole teeth, the output waveform detected by the magnetic sensor can show a highly accurate value according to the electrical angle, and the degree of freedom in design is high. In addition, since a plurality of permanent magnets are not used and a plurality of poles are not magnetized, the manufacturing is easy and it can be realized at a low price. Since only one permanent magnet is used, a ferrite magnet can be used, it can be used at a high temperature, and can be constructed at low cost.

D. Fourth embodiment:
FIG. 14 is an explanatory diagram showing a schematic configuration of a magnetic encoder as the fourth embodiment. FIG. 14A shows a schematic front view of the magnetic encoder 10D of the magnetic encoder 10D as viewed from the front, and FIG. 14B shows a schematic side view of the magnetic encoder 10D as viewed from the side. FIG. 14C is an enlarged view of a portion of the N pole teeth 25ND and S pole teeth 25SD that are periodically formed along the circumferential center line Jcc via the magnetic pole gap gm, and the circumferential center line Jcc is straightened. It is shown in a state of being expanded into a shape.

  In the magnetic drum 21C of the magnetic encoder 10C of the third embodiment, the shapes of the N pole teeth 25NC and the S pole teeth 25SC that are periodically provided along the circumferential center line Jcc are the center shapes of the respective tips. A trapezoidal wave is formed around the line Jcc. On the other hand, in the magnetic drum 21D of the magnetic encoder 10D of the present embodiment, the shapes of the N pole teeth 25ND and the S pole teeth 25SC periodically provided along the circumferential center line Jcc are the respective tip shapes. Is sinusoidal around the circumferential center line Jcc. The other configuration of the magnetic encoder 10D of the present embodiment is the same as that of the magnetic encoder 10C of the third embodiment.

  FIG. 15 is an explanatory diagram showing the A-phase sensor signal Vsa output from the A-phase sensor 28A in the magnetic encoder 10C of FIG. As described in the third embodiment, the A-phase sensor signal Vsa output from the A-phase sensor 28A indicates the strength of the magnetic field detected at each position along the circumferential center line Jcc. A periodic waveform that periodically changes every time the electrical angle θ advances by 2π [rad]. In particular, in the present embodiment, as described above, the shapes of the N-pole teeth 25ND and the S-pole teeth 25SC are sinusoidal with the respective tip shapes arranged via the gap centered on the circumferential center line Jcc. Accordingly, a sinusoidal magnetic pole gap gm is formed. For this reason, the A-phase sensor signal Vsa is a sine wave (sin θ) -like signal (sine wave signal) with less distortion. Although not shown, the same applies to the B phase sensor signal Vsb output from the B phase sensor 28B.

  Therefore, the waveform detected and output by the magnetic sensor is a waveform that periodically changes according to the electrical angle θ in the direction of the circumferential center line Jcc, and does not have a flat portion in the waveform. Since the sine wave is a waveform that changes symmetrically with the center value between the value and the minimum value as a reference, the rotation angle (rotation position) can be detected with high resolution and high accuracy.

  However, as shown in FIG. 15, the A-phase sensor signal Vsa has a waveform that is biased toward the positive side, that is, the N pole side, from the median value Vmc indicating zero magnetic field. The same applies to the B-phase sensor signal Vsb. This is because the length of the magnetic path from the N pole portion 231N (see FIG. 13) of the permanent magnet 231 to the tooth 213ND serving as the N pole tooth 25ND is changed from the S pole portion 231S (see FIG. 13) of the permanent magnet 231 to the S pole. It is inferred that the length of the magnetic path to the tooth 213SD that becomes the tooth 25SD is longer.

E. Fifth embodiment:
FIG. 16 is an explanatory diagram showing a schematic configuration of a magnetic encoder as the fifth embodiment. FIG. 16A shows a schematic front view of the magnetic encoder 10E as viewed from the front, and FIG. 16B shows a schematic side view of the magnetic encoder 10E as seen from the side. FIG. 16C shows a state in which a part of the N pole teeth 25NE periodically formed along the circumferential center line Jcc via the magnetic pole gap gn is enlarged, and the circumferential center line Jcc is expanded linearly. Is shown.

  In the magnetic drum 21D of the magnetic encoder 10D of the fourth embodiment, the shapes of the N-pole teeth 25NC and the S-pole teeth 25SD periodically provided along the circumferential center line Jcc are the tip shapes of the respective tips. A sine wave shape is formed around the line Jcc, and the magnetic gap gm is a sine wave-shaped both sine wave gap on both the N pole side and the S pole side. In contrast, in the magnetic drum 21E of the magnetic encoder 10E of the present embodiment, the tip shape of the second drum portion 220E is not the periodic pole tooth shape like the S pole tooth 25SD of the fourth embodiment. Each linear portion parallel to the circumferential center line Jcc corresponds to the S pole tooth 25SE, and the tip shape of the N pole tooth 25NE is sinusoidal around the circumference center line Jcc. The magnetic gap gn is a sine wave sine wave gap only on the N pole side. In addition, the other structure of the magnetic encoder 10E of this embodiment is the same as that of the magnetic encoder 10C of 3rd Embodiment similarly to the magnetic encoder 10D of 4th Embodiment.

  FIG. 17 is an explanatory diagram showing the A-phase sensor signal Vsa output from the A-phase sensor 28A in the magnetic encoder of FIG. Also in the present embodiment, as in the fourth embodiment described above, the A-phase sensor signal Vsa output from the A-phase sensor 28A is a sine wave (sin θ) -like signal (sinusoidal wave signal) with less distortion. In the fourth embodiment, the A-phase sensor signal Vsa has a waveform having an offset biased to the positive side of the median value Vmc indicating the zero magnetic field, that is, to the N pole side. In the embodiment, the waveform has no offset centered on the A-phase sensor signal Vsaha and the median value Vmc indicating the zero magnetic field. Although not shown, the same applies to the B phase sensor signal Vsb output from the B phase sensor 28B.

  Therefore, the waveform detected and output by the magnetic sensor is a waveform that periodically changes according to the electrical angle θ in the direction of the circumferential center line Jcc, and does not have a flat portion in the waveform. Since the sine wave is a waveform that changes symmetrically with the center value between the value and the minimum value as a reference, the rotation angle (rotation position) can be detected with high resolution and high accuracy. Further, since the A-phase sensor signal Vsa and the B-phase sensor signal Vsb have no offset, a circuit for removing the offset is unnecessary, which is advantageous in terms of signal processing.

  The present invention is an embodiment in which a high resolution is achieved with multipolarization (mechanical angle = one rotation and a plurality of magnetic angles are formed). This multipole and single pole (mechanical angle = one rotation, N / By using the magnetic angle of only the S2 pole) on the same axis, the absolute position information of the rotation angle can be obtained even when the power is turned on without the backup power supply.

F. Variation:
F1. Modification 1:
In the above embodiment, the magnetic encoder includes a signal processing circuit that detects a rotation angle (rotation position) based on a sensor signal output from the magnetic sensor, but does not include a signal processing circuit. A sensor signal output from the magnetic sensor may be output to an external signal processing circuit. When the signal processing circuit is mounted on the circuit board of the magnetic encoder, it is possible to detect the rotation angle with high accuracy by reducing the influence of noise and the like on the sensor signal. On the other hand, when the signal processing circuit is provided outside, the rotation angle can be detected by various types of signal processing, and the versatility is high.

F2. Modification 2:
In the first embodiment and the second embodiment, the first drum portion and the second drum portion are attracted to one permanent magnet, so that the magnetic pole of the first drum portion becomes the N pole, and the second drum Although the case where the magnetic pole of the portion is the S pole has been described as an example, the reverse may be possible. The magnetic drum can also be configured by magnetizing the first drum portion outward or inward in the radial direction and magnetizing the second drum portion in the direction opposite to the first drum portion. it can. In this case, the permanent magnet can be omitted.

  In the third embodiment, the substantially disc-shaped first drum portion is attracted to the N-pole magnetic pole of one permanent magnet, and the substantially ring-shaped second drum portion is attached to the other S-pole magnetic pole. The case where the magnetic pole of the first drum portion is set to the N pole and the magnetic pole of the second drum portion is set to the S pole by adsorbing through the drum portion 3 is described as an example. . Also, by magnetizing the first drum portion outward or inward in the radial direction and magnetizing the second drum portion or the third drum portion in the direction opposite to the first drum portion, A magnetic drum can be constructed. In this case, the permanent magnet can be omitted.

F3. Modification 3:
In the above-described embodiment, the configuration in which the two magnetic sensors are arranged to be shifted to the position corresponding to the phase difference of π / 2 in electrical angle has been described as an example. However, the two magnetic sensors are π / 3 or 2π in electrical angle. It is good also as a structure shifted and arrange | positioned to the position corresponded to / 3 phase difference. When two magnetic sensors are arranged so as to be shifted to a position corresponding to a phase difference of π / 2 in terms of electrical angle, the rotational state of a two-phase rotating electric machine (hereinafter also referred to as “electromechanical device”) It is possible to control the rotational operation of the two-phase electromechanical device with high accuracy by applying the encoder as an encoder that detects the above. In the case where the two magnetic sensors are arranged to be shifted to a position corresponding to a phase difference of π / 3 or 2π / 3 in terms of electrical angle, the encoder is used to detect the rotational state of a three-phase electromechanical device. By applying this, it is possible to control the rotational operation of the three-phase electromechanical device with high accuracy. The rotating electrical machine (electric machine device) is an electric motor, a generator, or the like.

F4. Modification 4:
The magnetic encoder of the above-described embodiment can be applied as an encoder of various rotating bodies, and can be applied as an encoder in an electric mobile body, an electric mobile robot, or a medical device drive device.

  FIG. 18 is an explanatory diagram illustrating an electric bicycle (electric assist bicycle) that is an example of a moving body. This bicycle 3300 is provided with a power generation device 3310 composed of a motor provided with the magnetic encoder of the above embodiment on a front wheel, and a control circuit 3320 and a rechargeable battery 3330 are provided on a frame below the saddle. ing. The power generation device 3310 assists traveling by driving the front wheels using the electric power from the rechargeable battery 3330. In addition, the electric power regenerated by the power generation device 3310 is charged to the rechargeable battery 3330 during braking. The control circuit 3320 is a circuit that controls the speed change of the speed change mechanism by controlling the drive and regeneration of the drive motor unit of the power generation device 3310 and the drive and regeneration of the speed change control motor unit.

  FIG. 19 is an explanatory diagram illustrating an example of a robot. The robot 3400 includes first and second arms 3410 and 3420, and a power generation device 3430 including a motor provided with the magnetic encoder of the above-described embodiment. The power generation device 3430 is used when the second arm 3420 as a driven member is rotated horizontally.

  FIG. 20 is an explanatory diagram showing an example of a dual-arm seven-axis robot. The double-arm 7-axis robot 3450 includes a joint motor 3460, a gripper motor 3470, an arm 3480, and a gripper 3490. Each motor 3460, 3470, 3480, 3490 is provided with the magnetic encoder of the above embodiment. The joint motor 3460 is disposed at a position corresponding to a shoulder joint, an elbow joint, and a wrist joint. The joint motor 3460 includes two motors for each joint in order to move the arm 3480 and the grip portion 3490 in a three-dimensional manner. In addition, the gripper motor 3470 opens and closes the gripper 3490 and causes the gripper 3490 to grip an object.

  FIG. 21 is an explanatory diagram illustrating an example of a vertical articulated robot. As shown in FIG. 21, the vertical articulated robot 3640 includes a main body portion 3641, an arm portion 3642, a robot hand 3645, and the like. The main body 3641 is fixed on, for example, a floor, a wall, a ceiling, or a movable carriage. The arm portion 3642 is provided movably with respect to the main body portion 3641. The main body portion 3641 has a drive unit (not shown) that generates power for rotating the arm unit 3642, and a control unit that controls the drive unit. Etc. are built-in. As this drive unit, it is possible to use a power generation device configured by a motor provided with the magnetic encoder of the above embodiment.

  The arm portion 3642 includes a first frame 3642a, a second frame 3642b, a third frame 3642c, a fourth frame 3642d, and a fifth frame 3642e. The first frame 3642a is connected to the main body 3641 so as to be rotatable or refractable via a rotational refraction axis. The second frame 3642b is connected to the first frame 3642a and the third frame 3642c via a rotational refraction axis. The third frame 3642c is connected to the second frame 3642b and the fourth frame 3642d via a rotational refraction axis. The fourth frame 3642d is connected to the third frame 3642c and the fifth frame 3642e via the rotational refraction axis. The fifth frame 3642e is connected to the fourth frame 3642d via the rotational refraction axis. The arm portion 3642 is configured such that each frame 3642a to 3642e moves by being rotated or refracted around each rotational refraction axis under the control of a control portion (not shown).

  A hand connection portion 3634 is connected to the side of the arm portion 3642 opposite to the side on which the fourth frame 3642d is provided in the fifth frame 3642e, and a robot hand 3645 is attached to the hand connection portion 3634.

  The robot hand 3645 includes a base 3645a and a finger 3645b connected to the base 3645a. The various power generation devices described above are incorporated in the connection portion between the base portion 3645a and the finger portion 3645b and each joint portion of the finger portion 3645b. When the power generation device is driven, the finger portion 3645b is bent and the object can be gripped. This power generation device is an ultra-small motor, and can realize a robot hand 3645 that reliably holds an object while being small. Accordingly, it is possible to provide a highly versatile robot that can perform a complex operation using the small and lightweight robot hand 3645.

  FIG. 22 is an explanatory diagram showing an example of a robot with double-arm casters. As shown in FIG. 22, the robot 3762 with a double-arm caster includes a vehicle body portion 3763. The vehicle body portion 3763 includes a vehicle body main body 3763a, and four wheels 3763b are installed on the ground side of the vehicle body main body 3763a. The vehicle body 3763a has a built-in rotation mechanism that drives the wheels 3763b. Further, a control unit 3764 for controlling the posture and operation of the robot 3762 is built in the vehicle body 3766a.

  A main body rotating portion 3765 and a main body portion 3766 are stacked on the vehicle body main body 3766a in this order. The main body rotation unit 3765 is provided with a rotation mechanism that rotates the main body unit 3766. The main body 3766 rotates about the vertical direction as the center of rotation. A pair of imaging devices 3767 is installed on the main body 3766, and the imaging device 3767 images the periphery of the robot 3762 with a double-arm caster. Then, the distance between the photographed object and the imaging device 3767 can be detected.

  A left arm portion 3768 and a right arm portion 3769 are installed on two opposing surfaces of the side surface of the main body portion 3766. Each of the left arm portion 3768 and the right arm portion 3769 includes an upper arm portion 3770, a lower arm portion 3771, and a hand portion 3772 as movable portions. The upper arm portion 3770, the lower arm portion 3771, and the hand portion 3772 are connected so as to be rotatable or bendable. The main body 3766 includes a rotation mechanism 3773 that rotates the upper arm 3770 with respect to the main body 3766. The upper arm portion 3770 includes a rotation mechanism 3773 that rotates the lower arm portion 3771 with respect to the upper arm portion 3770. The lower arm portion 3771 includes a rotation mechanism 3773 that rotates the hand portion 3772 with respect to the lower arm portion 3771. Further, the lower arm portion 3771 incorporates a rotation mechanism 3773 that twists with the longitudinal direction of the lower arm portion 3771 as the rotation axis.

  The hand portion 3772 includes a hand main body 3772a and a gripping portion 3772b as a pair of plate-like movable portions located at the tip of the hand main body 3772a. The hand main body 3772a incorporates a linear motion mechanism 3774 that moves the gripping portion 3772b to change the interval between the gripping portions 3772b. The hand portion 3772 can grip an object to be gripped by opening and closing the grip portion 3772b.

  The rotation mechanism 3773 and the linear motion mechanism 3774 are provided with a power generation device composed of a motor provided with the magnetic encoder of the above embodiment. Therefore, the rotation mechanism 3773 can smoothly change the rotation direction without rattling even when the rotation direction is reversed. The linear motion mechanism 3774 can smoothly change the movement direction without rattling even when the movement direction is reversed. Therefore, the robot 3762 with a double arm caster can move the left arm portion 3768 and the right arm portion 3769 with high positional accuracy.

  Further, the rotating mechanism that rotates the wheel 3763b and the rotating mechanism that rotates the main body 3766 include the power generation device described above. Therefore, the robot 3762 with a two-arm caster can be rotated without rattling even when the traveling direction is changed. And the robot 3762 with a double-arm caster can be rotated without rattling even when the rotation direction of the main body 3766 is changed.

  FIG. 23 is an explanatory view showing a railway vehicle. The railway vehicle 3500 includes a power generation device 3510 and wheels 3520. This power generation device 3510 drives wheels 3520. Furthermore, the power generation device 3510 is used as a generator when the railway vehicle 3500 is braked, and electric power is regenerated. As the power generation device 3510, a power generation device configured by a motor provided with the magnetic encoder of the above-described embodiment is used.

  The present invention is not limited to the above-described embodiments, examples, and modifications, and can be realized with various configurations without departing from the spirit thereof. For example, the technical features in the embodiments, examples, and modifications corresponding to the technical features in each embodiment described in the summary section of the invention are to solve some or all of the above-described problems, or In order to achieve part or all of the above-described effects, replacement or combination can be performed as appropriate. Further, if the technical feature is not described as essential in the present specification, it can be deleted as appropriate.

DESCRIPTION OF SYMBOLS 10 ... Magnetic encoder 10B ... Magnetic encoder 10C ... Magnetic encoder 20 ... Detection part 21 ... Magnetic drum 21B ... Magnetic drum 21C ... Magnetic drum 22 ... Side part 22C ... Side part 22h ... Reference hole 23 ... Disc part 23h ... Reference | standard Hole 24 ... outer peripheral surface portion 24B ... outer peripheral surface portion 25N ... N pole tooth 25S ... S pole tooth 25NB ... N pole tooth 25SB ... S pole tooth 25Nm ... N pole tooth 25Sm ... S pole tooth 25ND ... N pole tooth 25SD ... S pole tooth 25NE ... N pole tooth 25SE ... S pole tooth 26 ... Shaft 26h ... Screw hole 27 ... Reference position sensor 27C ... Light projecting part 27R ... Light receiving part 28A ... Magnetic pole sensor (A phase sensor)
28B ... Magnetic sensor (phase B sensor)
DESCRIPTION OF SYMBOLS 30 ... Signal processing part 31 ... Signal processing circuit 32 ... Connector 40 ... Housing 42 ... Hole of housing 60 ... Circuit board 60C ... Circuit board 61 ... Circuit board 62 ... Circuit board 63 ... Conductor pattern 64 ... Solder 65 ... Mounting terminal DESCRIPTION OF SYMBOLS 70 ... Motor 72 ... Shaft 72h ... Screw hole 72S ... Spacer 74 ... Holder structure 74a ... Holder part 74b ... Fastening member 76 ... Insulation material 78 ... Fixing screw 79 ... Air layer 80 ... Coupling 210 ... Drum part 210C ... Drum part 210D ... Drum part 210E ... Drum part 211 ... Disk part 212 ... Shaft hole 212C ... Shaft hole 213 ... Tooth 213N ... Tooth 213S ... Tooth 213ND ... Tooth 213SD ... Tooth 213NE ... Tooth 213SE ... Tooth 214 ... Reference hole 220 ... Drum part 220Ca ... Drum part 220Cb ... Drum part 20D ... Drum part 220E ... Drum part 221 ... Disk part 221C ... Disk part 222 ... Shaft hole 222C ... Shaft hole 223 ... Tooth 223C ... Cylindrical part 223S ... Tooth 224 ... Reference hole 224C ... Side 230 ... Permanent magnet part 231 ... Permanent magnet part 231 232 ... Shaft 233 ... Side 234 ... Side 3300 ... Bicycle 3310 ... Power generator 3320 ... Control circuit 3330 ... Rechargeable battery 3400 ... Robot 3410 ... First arm 3420 ... Second arm 3430 ... Power generator 3450 ... Dual arm 7 Axis robot 3460 ... joint motor 3470 ... gripping part motor 3480 ... arm 3490 ... gripping part 3500 ... railway vehicle 3510 ... power generator 3520 ... wheel 3640 ... vertical articulated robot 3641 ... main body part 3642 ... arm part 3642a ... first part 3642b ... 2nd frame 3642c ... 3rd frame 3642d ... 4th frame 3642e ... 5th frame 3642e ... Hand connection part 3645 ... Robot hand 3645a ... Base part 3645b ... Finger part 3762 ... Robot with two-arm casters 3863 ... Car body part 3663a ... Car body body 3763b ... Wheel 3764 ... Control part 3765 ... Main body rotating part 3766 ... Main body part 3767 ... Imaging device 3768 ... Left arm part 3769 ... Right arm part 3770 ... Upper arm part 3771 ... Lower arm part 3772 ... Hand part 3772a ... Hand body 3772b ... Grip Part 3773 ... rotation mechanism 3774 ... linear motion mechanism

Claims (8)

A magnetic encoder having a magnetic drum and a magnetic sensor,
The magnetic drum is
A permanent magnet magnetized parallel to the rotational axis of the magnetic drum;
A first drum portion and a second drum portion provided so as to sandwich the permanent magnet, wherein the first drum portion magnetized to the N pole by the permanent magnet and the first drum portion magnetized to the S pole Two drum parts, or the first drum part magnetized to the S pole by the permanent magnet and the second drum part magnetized to the N pole,
A magnetic gap is formed between the first drum portion and the second drum portion in the rotation direction of the magnetic drum,
Since at least one of the first drum portion and the second drum portion has a periodic pole tooth shape in the rotation direction of the magnetic drum, the shape of the magnetic gap is formed with a period. ,
The plurality of magnetic sensors are magnetic encoders provided at positions where the pole tooth shape passes. The magnetic encoder according to claim 1,
In the cylindrical outer peripheral surface of the magnetic drum, the first drum portion has N pole pole teeth and the second drum portion has S pole pole teeth, or the first drum portion has S pole poles. A magnetic encoder having pole teeth and N pole pole teeth in the second drum portion. The magnetic encoder according to claim 1,
The magnetic drum is
A disc-shaped first drum portion perpendicular to the rotation axis;
A ring-shaped second drum portion disposed on the outer periphery of the first drum portion;
With
A magnetic encoder having a periodic pole-tooth shape in the rotation direction of the magnetic drum in the plane of the first drum portion and the second drum portion. A magnetic encoder according to any one of claims 1 to 3,
The periodic pole tooth shape is a waveform in which the magnetic change detected by the magnetic sensor periodically changes in accordance with the electrical angle in the rotation direction, and does not have a flat portion and is a maximum. A magnetic encoder having an outer shape having a waveform that changes symmetrically with a center value between a value and a minimum value as a reference. A magnetic encoder according to any one of claims 1 to 4,
The magnetic sensor is mounted on a circuit board,
A signal processing circuit for processing a signal output from the magnetic sensor is further mounted on the circuit board. An electromechanical device having a rotating shaft,
An electromechanical device comprising the magnetic encoder according to any one of claims 1 to 5 for detecting a rotation state of the rotating shaft.   A robot comprising the electromechanical device according to claim 6.   A moving body comprising the electromechanical device according to claim 6.

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