JP2018189426A - Encoder device, driving device, stage device, and robot device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an encoder device that stably operates.SOLUTION: An encoder device EC includes: a detector 1 for detecting information about the position on which a rotating body rotates; a magnet 21, which rotates relatively to the detector 1; and a signal generation unit 31 located in the direction perpendicular to the rotational axis AX of the rotating body for the magnet 21, the signal generation unit generating a detection signal by the large Barkhausen effect based on changes in the magnetic field formed by the magnet 21, the magnet being magnetized in the direction perpendicular to the rotational axis AX of the magnet 21.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an encoder device, a drive device, a stage device, and a robot device.

  The encoder device is mounted on various devices such as a robot device (see, for example, Patent Document 1 below). For example, the encoder device is required to efficiently detect the magnetic field of the magnet.

JP-A-8-50034

According to the first aspect of the present invention, a detection unit that detects rotational position information of a rotating body, a magnet that rotates relative to the detection unit, and a magnet that is orthogonal to the rotation axis of the rotating body. A signal generation unit that is arranged in a direction and generates a detection signal by a large Barkhausen effect based on a change in a magnetic field formed by a magnet,
An encoder device is provided in which the magnet is magnetized in a direction orthogonal to the rotation axis.

  According to the second aspect of the present invention, there is provided a drive device including the encoder device of the first aspect and a drive unit that supplies a drive force to the rotating body.

  According to a third aspect of the present invention, there is provided a stage apparatus including the driving device according to the second aspect and a stage moved by the driving device.

  According to a fourth aspect of the present invention, there is provided a robot apparatus including the driving device according to the second aspect and an arm that is moved by the driving device.

It is a figure which shows the encoder apparatus which concerns on 1st Embodiment. It is a figure which shows the magnet and signal generation part which concern on 1st Embodiment. It is a figure which shows the magnetic field which the magnet which concerns on 1st Embodiment forms. It is a figure which shows the circuit structure of the position detection part and electric power supply part which concern on 1st Embodiment. It is a figure which shows the encoder apparatus which concerns on 2nd Embodiment. It is a figure which shows the magnet which concerns on embodiment. It is a figure which shows the magnet which concerns on embodiment. It is a figure which shows the encoder apparatus which concerns on embodiment. It is a figure which shows the signal generation part which concerns on embodiment. It is a figure which shows the drive device which concerns on embodiment. It is a figure which shows the stage apparatus which concerns on embodiment. It is a figure which shows the robot apparatus which concerns on embodiment.

[First Embodiment]
A first embodiment will be described. FIG. 1 is a diagram illustrating an encoder device according to the first embodiment. The encoder device EC detects position information (movement information) of a moving body (moving member). The encoder device EC is, for example, a rotary encoder. In this case, the moving body is a rotating body SF (rotating member), and the position information includes rotational position information. In the following description, a direction parallel to the rotation axis AX of the rotating body SF is appropriately referred to as an axial direction, and a direction perpendicular to the axial direction is referred to as a radial direction. Further, the rotation direction of the rotating body SF and the rotation direction of the member that rotates substantially coaxially with the rotating body SF are appropriately referred to as a rotation direction.

  The rotating body SF includes, for example, an output shaft (for example, an object interlocked with an electric element, a shaft, and a rotor) in a driving device MTR such as an electric motor. The rotating body SF may be a working shaft connected to the output shaft of the drive device MTR. The action shaft includes, for example, a shaft connected to the output shaft of the drive device MTR via a transmission.

  The rotational position information includes one or both of multi-rotation information and angular position information. The multi-rotation information includes information indicating the number of rotations (eg, 1 rotation, 2 rotations, and multiple rotations). The angular position information includes information indicating an angular position (rotation angle) of less than one rotation. The encoder device EC is, for example, a multi-rotation absolute encoder. In this case, the rotational position information includes multi-rotation information and angular position information.

  The drive device MTR includes, for example, a main body BD and a control unit MC. The main body BD (motor main body) includes, for example, a rotor, a stator, and a body. The rotor includes, for example, an electric element of an electric motor. The stator includes, for example, a magnet (for example, a permanent magnet) of an electric motor. The body houses the rotor and the stator. The stator is fixed to the body, and the rotor is supported to be rotatable with respect to the body.

  The rotor rotates with respect to the stator by the electric power supplied from the power source PW. The power source PW (first power source) is, for example, a main power source of a device (eg, drive device, stage device, robot device) on which the encoder device EC is mounted. The rotating body SF is fixed to the rotor and rotates with respect to the stator together with the rotor.

  The control unit MC (motor control unit) controls the driving of the rotating body SF based on the rotational position information detected by the encoder device EC. For example, the control unit MC controls the power supplied from the power source PW as the power consumed for the rotation of the rotor based on the rotational position information. For example, the control unit MC controls the power supplied to the main body BD so that at least one of the angular position, angular velocity, and angular acceleration of the rotor approaches the target value.

  Next, each part of the encoder device EC will be described. The encoder device EC includes a position detection unit 1 and a power supply unit 2. The position detection unit 1 detects rotational position information of the rotating body SF. The position detection unit 1 includes a multi-rotation information detection unit 1A and an angle detection unit 1B. The multi-rotation information detection unit 1A detects multi-rotation information of the rotating body SF. The angle detection unit 1B detects the angular position of the rotating body SF.

  The angle detector 1B detects position information (angular position information, absolute or relative position information) within one rotation of the scale S. The angle detection unit 1B includes one or both of an optical encoder and a magnetic encoder. The angle detection unit 1B includes an optical encoder in the present embodiment, but may include a magnetic encoder.

  The angle detection unit 1B includes a scale S, an irradiation unit 11, a detection unit 12, and a processing unit 13. The scale S is fixed to the rotating body SF. The scale S is a disk-shaped member, for example. In this case, the radial direction is the radial direction of the scale S, and the rotation direction is the circumferential direction of the disk-shaped scale S. The scale S is, for example, a member made of glass, metal, or resin. The scale S includes an incremental pattern INC and an absolute pattern ABS. The incremental pattern INC and the absolute pattern ABS are provided on the surface Sa of the scale S, for example. One or both of the incremental pattern INC and the absolute pattern ABS may be provided on the surface Sb of the scale S opposite to the surface Sa.

  The irradiation unit 11 (light emitting unit) irradiates light to the incremental pattern INC and the absolute pattern ABS of the scale S. The irradiation unit 11 includes, for example, a light emitting element (eg, a solid light source) such as an LED (light emitting diode). The detection unit 12 (sensor unit, light receiving unit) detects light emitted from the irradiation unit 11 and passing through the incremental pattern INC, and light emitted from the irradiation unit 11 and passing through the absolute pattern ABS. The irradiation unit 11 includes, for example, a light receiving element (eg, a photoelectric conversion element) such as a photodiode.

  The angle detector 1 </ b> B detects the angular position information within one rotation of the rotating body SF by reading the patterning information of the scale S with the detector 12. The patterning information of the scale S detected by the angle detection unit 1B is, for example, a light / dark pattern such as a transmission pattern (eg, a slit) or a reflection pattern (eg, a reflective film) on the scale S. In FIG. 1, the angle detector 1B is of a reflective type. In this case, the detection unit 12 detects the light reflected by the scale S. The angle detector 1B may be a transmissive type. In this case, the detection unit 12 detects light transmitted through the scale S.

  The detection unit 12 supplies a signal (detection signal) indicating the detection result to the processing unit 13. The processing unit 13 detects the angular position of the rotating body SF using the detection result of the detection unit 12. For example, the processing unit 13 detects the angular position information of the first resolution using the result of detecting the light from the absolute pattern ABS. Further, the processing unit 13 performs an interpolation operation on the angular position information of the first resolution using the result of detecting the light from the incremental pattern INC, so that the angular position information of the second resolution higher than the first resolution. Is detected.

  The multi-rotation information detection unit 1A detects angular position information of the same rotating body SF as the detection target of the angle detection unit 1B. The multi-rotation information detection unit 1A includes one or both of a magnetic encoder and an optical encoder. The multi-rotation information detection unit 1A includes a magnetic encoder in the present embodiment, but may include an optical encoder. The multi-rotation information detection unit 1A includes a magnet 21, a magnetic detection unit 22, a processing unit 23, and a storage unit 24.

  The magnet 21 (magnetic scale) rotates relative to the detection unit (for example, a part of the position detection unit 1). For example, the magnet 21 rotates relative to the magnetic detection unit 22 by the rotation of the rotating body SF. The magnet 21 is provided on a scale S (first rotating body) fixed to the rotating body SF. For example, the scale S rotates with the rotating body SF, and the magnet 21 rotates in conjunction with the rotating body SF. Moreover, the magnet 21 is arrange | positioned in the direction which cross | intersects the rotating shaft direction of rotating shaft AX of rotary body SF. In the present embodiment, the magnet 21 is disposed along the radial direction. The magnet 21 is a ring-shaped member, for example. In this case, the radial direction is the radial direction of the magnet 21, and the rotation direction is the circumferential direction of the magnet 21.

  For example, the magnet 21 is provided on the surface Sa on the same side as the incremental pattern INC and the absolute pattern ABS in the scale S. For example, the magnet 21 is disposed outside the incremental pattern INC and the absolute pattern ABS in the radial direction on the surface Sa of the scale S. The magnet 21 may be provided on the surface Sb opposite to the surface Sa on which the incremental pattern INC and the absolute pattern ABS are provided on the scale S.

  The magnetic detection unit 22 is fixed (supported) to a member outside the rotating body SF. The relative positions (relative angular positions) of the magnet 21 and the magnetic detection unit 22 change due to the rotation of the rotating body SF. The strength and direction of the magnetic field on the magnetic detection unit 22 formed by the magnet 21 changes according to the rotation of the rotating body SF. The magnetic detection unit 22 detects a magnetic field formed by the magnet 21. The magnetic detection unit 22 includes a magnetic sensor 25 and a magnetic sensor 26.

  The processing unit 23 detects (calculates) the multi-rotation information of the rotating body SF based on the result of the magnetic detection unit 22 detecting the magnetic field formed by the magnet 21. For example, the processing unit 23 uses the detection result of the magnetic sensor 25 as the A-phase signal and uses the detection result of the magnetic sensor 26 as the B-phase signal to detect the multi-rotation information. The processing unit 23 is, for example, a multi-rotation processing unit that processes multi-rotation information. The storage unit 24 stores position information detected and processed by the processing unit 23 based on a storage command (data write command) of position information (eg, multi-rotation information) from the processing unit 23.

  When the magnetic detection unit 22 is provided on the scale S, the magnet 21 may be provided outside the scale S at a position different from the magnetic detection unit 22. For example, the magnet 21 may be provided at a position that rotates relative to the magnetic detection 22 provided on the scale S by the rotation of the scale S.

  In the present embodiment, the encoder device EC includes a synthesis unit 27. The synthesizer 27 acquires the angular position information of the second resolution detected by the processor 13. Further, the composition unit 27 acquires the multi-rotation information of the rotating body SF from the storage unit 24 of the multi-rotation information detection unit 1A. The combining unit 27 combines the angular position information from the processing unit 13 and the multi-rotation information from the multi-rotation information detection unit 1A, and calculates the rotational position information of the rotating body SF. For example, when the detection result of the processing unit 13 is θ [rad] and the detection result of the multi-rotation information detection unit 1A is n rotations, the synthesis unit 27 uses (2π × n + θ) [rad] as rotation position information. Is calculated. The rotational position information may be information obtained by combining multi-rotation information and angular position information.

  The encoder device EC includes a communication unit (eg, an external communication unit, an external connection interface), and this communication unit is connected to the control unit MC so as to be communicable by wire or wirelessly. The communication unit of the encoder device EC supplies (transmits) the digital rotational position information to the control unit MC. The controller MC appropriately decodes the rotational position information supplied from the encoder device EC. The controller MC controls the rotation of the rotating body SF by controlling the power (drive power) supplied to the main body BD using the rotational position information.

  The encoder device EC detects the rotational position information of the rotating body SF in each of the normal state and the backup state in which the power supply sources consumed by the encoder device EC are different. The normal state includes a state in which power of the power source PW is turned on, a state in which the power source PW is turned on, a state in which power is supplied from the power source PW to a device in which the encoder device EC is mounted, and It includes at least one state in which power is supplied from the power source PW to the encoder device EC. The above-described backup state includes, for example, a state where the power of the power source PW is not turned on, a state where the power source PW is turned off, and a state where no power is supplied from the power source PW to the device on which the encoder device EC is mounted The encoder device EC includes at least one state in which power is not supplied from the power source PW.

  At least a part of the position detection unit 1 (for example, the multi-rotation information detection unit 1A and the angle detection unit 1B) detects the rotation position information of the rotating body SF by the power supplied from the power source PW in the normal state. The power supply PW is consumed in the normal state for the power consumed for driving the rotating body SF and the detection operation of the position detection unit 1 (for example, the operation for calculating and detecting angular position information and multi-rotation information). Supply power. At least a part of the position detection unit 1 receives power supply from the power supply PW and detects rotational position information of the rotating body SF. The control unit MC controls the rotation of the rotating body SF by adjusting the power supplied from the power source PW based on the detection result of the position detection unit 1 and supplying the adjusted power to the main body BD.

  At least a part of the position detection unit 1 (eg, the multi-rotation information detection unit 1A) is supplied with power supplied from a second power source (eg, power supply unit 2) different from the power source PW in a backup state different from the normal state. Can be operated by.

  For example, the power supply unit 2 intermittently (selectively, intermittently) supplies power to at least a part of the position detection unit 1 (for example, the multi-rotation information detection unit 1A) in the backup state. In the backup state, the position detection unit 1 receives power supply from the power supply unit 2 and detects at least a part (eg, multi-rotation information) of the rotational position information of the rotating body SF. For example, the multi-rotation information detection unit 1A receives power supply intermittently from the power supply unit 2 and intermittently detects the multi-rotation information. The multi-rotation information detected by the multi-rotation information detection unit 1A in the backup state is controlled when, for example, power supply from the power source PW is started and the backup state is switched to the normal state (eg, when the drive device is started). The part MC is used to control the rotation of the rotating body SF.

  The multi-rotation information detection unit 1A detects multi-rotation information of the rotating body SF in each of a normal state in which power is supplied from the power supply PW and a backup state in which power is supplied from the power supply unit 2. For example, the encoder device EC switches from the normal state to the backup state when the power supply of the power source PW is stopped. The encoder device EC switches from the backup state to the normal state when the power supply of the power source PW is started. When the encoder device EC is switched between the normal state and the backup state, the multi-rotation information detection unit 1A continues to detect multi-rotation information (continues calculation).

  For example, the angle detection unit 1B does not detect (calculate) angle information in a backup state in which power supply from the power supply PW is cut off. For example, the second power supply does not supply power to the angle detection unit 1B in the backup state based on a command from the control unit MC. For example, the angle detection unit 1B is in a state where power supply is cut off in the backup state, and does not detect angular position information.

  The power supply unit 2 includes a magnet 21, a signal generation unit 31, a switching unit 32, and a battery 33. The signal generation unit 13 is disposed in a direction intersecting the rotation axis of the magnet 21 with respect to the magnet 21. For example, the signal generation unit 31 is arranged in a direction (radial direction) perpendicular to the rotation axis of the magnet 21 with respect to the magnet 21. For example, the signal generator 13 is arranged in a direction intersecting the rotation axis direction of the rotation axis AX of the rotating body SF with respect to the magnet 21. The rotation axis of the magnet 21 is substantially coaxial with the rotation axis AX of the rotating body SF. The magnet 21 rotates relative to the signal generator 31 by the rotation of the rotating body SF. The magnetic field formed by the magnet 21 at the position of the signal generating unit 31 is changed by relative rotation between the magnet 21 and the signal generating unit 31. The signal generator 31 generates a detection signal (electric signal) by a large Barkhausen effect based on a change in the magnetic field formed by the magnet 21. The power supply unit 2 supplies power based on the detection signal generated by the signal generation unit 31.

  FIG. 2 is a diagram illustrating a magnet and a signal generator according to the first embodiment. In the following description, the XYZ orthogonal coordinate system shown in FIG. In this XYZ orthogonal coordinate system, the Z direction is an axial direction parallel to the rotation axis AX of the magnet 21. The X direction and the Y direction are directions perpendicular to the Z direction, respectively. In the following description, the state viewed from the Z direction is referred to as a rotation axis view. For each of the X direction, the Y direction, and the Z direction, the direction of the arrow is appropriately referred to as a + side (eg, + X side), and the direction opposite to the arrow is referred to as a − side (eg, −X side).

  The magnet 21 in this embodiment is magnetized in a direction orthogonal to the rotation axis AX. The magnet 21 is, for example, a plate-like member whose thickness direction is a direction parallel to the rotation axis AX. The magnet 21 is magnetized in the radial direction intersecting (eg, orthogonal) with the thickness direction. The orientation of the magnet 21 is set so that a magnetic field including a component in a direction perpendicular to the rotation axis AX (eg, the rotation direction of the rotating body, the rotation direction of the magnet 21) is formed. The magnet 21 is arranged so as to form an AC magnetic field on the outer side (eg, the side of the magnet 21) in the radial direction. The magnet 21 has a plurality of magnetic poles distributed on a plane perpendicular to the rotation axis AX. The magnet 21 has four or more magnetic poles in the rotation direction. In the magnet 21, for example, the number of magnetic poles in the rotation direction (the sum of the number of N poles 21a and the number of S poles 21b) is 4 or more, for example.

  The magnet 21 is an annular (or cylindrical) member, for example. The magnet 21 has a side surface 21c that curves along the rotation direction of the rotating body (or the magnet 21). The side surface 21c is a surface that faces a direction (eg, radial direction) intersecting a surface (eg, upper surface) on which the magnet 21 is disposed in the scale S. For example, the center of curvature of the side surface 21c substantially coincides with the rotation axis AX. The magnet 21 has an N pole 21a and an S pole 21b arranged in the rotational direction on the inner circumference side (inner edge side) and the outer circumference side (outer edge side), respectively. The magnet 21 in the present embodiment is a permanent magnet magnetized with 8 poles. For example, the magnet 21 has four magnetic poles on its inner peripheral side and four magnetic poles on its outer peripheral side. The number of magnetic poles of the magnet 21 in the rotation direction is 4 on each of the inner peripheral side and the outer peripheral side of the magnet 21.

  The angular position of the N pole 21a is shifted by 90 ° between the inner peripheral side and the outer peripheral side. The S pole 21b has an angular position shifted by 90 ° between the inner peripheral side and the outer peripheral side. The boundary between the N pole 21a and the S pole 21b has substantially the same angular position on the outer peripheral side and the inner peripheral side. The number of magnetic poles of the magnet 21 in the rotation direction is set to an arbitrary even number, and may be 2 or 6 or more.

  The magnet 21 forms a magnetic field having a component in the rotation direction by the N pole 21a and the S pole 21b adjacent in the rotation direction. For example, the magnetic lines of force M1 from the N pole 21a on the outer peripheral side of the magnet 21 are curved toward the adjacent S pole 21b.

  Since the signal generation unit 31 is arranged in a direction (eg, radial direction) orthogonal to the rotation axis AX of the rotating body (or the rotation axis of the magnet 21) with respect to the magnet 21, for example, the radial direction (relating to the rotation axis AX). (Radiation direction) is arranged outside the magnet 21. The signal generator 31 is disposed at a position facing the side surface 21c of the magnet 21, for example. At least a part of the signal generator 31 is arranged at a position farther from the rotation axis AX than the magnet 21. For example, the signal generator 31 is arranged so as not to overlap the magnet 21 in the rotational axis view. Note that the signal generator 31 may be disposed at a position that overlaps a part of the magnet 21 in the rotational axis view.

  The signal generating unit 31 includes a magnetic body 35 and a coil unit 36. The magnetic body 35 generates a large Barkhausen effect (also referred to as a large Barkhausen jump, Wiegand effect, or Barkhausen effect) due to a change in the magnetic field formed by the magnet 21. The magnetic body 35 is a magnetic sensitive part that feels magnetic force. The magnetic body 35 is a magnetic sensitive wire such as a composite magnetic wire, a Wiegand wire, or an amorphous magnetic alloy wire. Note that the large Barkhausen effect includes a movement of a domain wall inside the magnetic body at a time when the magnetic body is magnetized. A symbol Px in FIG. 2A indicates a position closest to the magnetic body 35 on a circumference around the rotation axis AX (eg, on the side surface 21c of the magnet 21). Reference sign Lx is a tangent at a circumferential position Px with the rotation axis AX as the center. In the following description, a direction parallel to the tangent line Lx is referred to as a tangential direction D1.

  The magnetic body 35 has a shape having a longitudinal direction and a lateral direction, and is arranged with the longitudinal direction facing the tangential direction D1 (Y direction). For example, the magnetic body 35 (see FIG. 2B) is a cylindrical member, and its axial direction (longitudinal direction) is substantially parallel to the tangential direction D1. For example, the magnetic body 35 has a shape extending substantially linearly in parallel with the tangential direction D1. An alternating magnetic field is applied to the magnetic body 35 in the axial direction (Y direction), and when the direction of the alternating magnetic field is reversed, a domain wall is generated from one end to the other end in the axial direction. Thus, when magnetized (including remagnetization), the magnetic body 35 has the property that the internal domain wall constituting the magnetic domain moves at a time, and the easy magnetization direction is the longitudinal direction (stretching direction, tangential direction). D1). Therefore, for example, in the signal generator 31, as a large Barkhausen effect, the magnetic body 35 is magnetized based on the rotation of the magnet 21, and the timing of changing the magnetization direction (eg, reversal of the magnetization direction (change in magnetic field) occurs. The sensor includes a pulse signal (detection signal) output from the coil section 36 at the timing.

  In FIG. 2A, reference numeral 35 a is an end portion of the magnetic body 35, and reference numeral 35 b is a central portion of the magnetic body 35. The symbol DXa is the distance between the end portion 35a of the magnetic body 35 and the magnet 21 in the direction perpendicular to the tangential direction D1. The symbol DXb is a distance between the central portion 35b of the magnetic body 35 and the magnet 21 in a direction perpendicular to the tangential direction D1. As shown in FIG. 2A, the magnetic body 35 has two end portions (eg, a first end portion on one end side and a second end portion on the other end side) in the easy magnetization direction (longitudinal direction, tangential direction D1). 35a and a central portion 35b between the two end portions 35a.

  In the present embodiment, since the signal generator 31 is disposed in the radial direction with respect to the magnet 21, for example, the central portion 35 a of the magnetic body 35 and the magnet 21 can be disposed close to each other. Further, when the signal generating unit 31 is arranged in the radial direction with respect to the magnet 21 and the sensors (eg, the detecting unit 12 and the magnetic detecting unit 22 in FIG. 1) are arranged in the axial direction with respect to the magnet 21, the signal generation is performed. It becomes easy to set the gap between the portion 31 and the magnet 21 and the gap between the sensor and the scale S or the magnet 21 independently. As shown in FIG. 2, for example, the signal generating unit 31 is located outside the magnet 21 c at a position that does not overlap the magnet 21 when viewed in the axial direction of the rotational axis AX of the rotating body (or viewed in the rotational axis direction of the magnet 21). It arrange | positions in the position which opposes the side surface 21c.

  The two end portions 35 a of the magnetic body 35 in the easy magnetization direction are arranged at positions farther from the magnet 21 than the central portion 35 b of the magnetic body 35. In FIG. 2A, the distance DXa is longer than the distance DXb due to the shape of the side surface 21 c of the magnet 21. The side surface 21c of the magnet 21 is curved so as to move away from the magnetic body 35 as it goes from the central portion 35b of the magnetic body 35 toward the end portion 35a. The side surface 21 c is curved so as to be convex with respect to the magnetic body 35. For this reason, the signal generation part 31 is arrange | positioned via the gap based on the distance DXa and the distance DXb with respect to the magnet 21 (for example, position where the magnet 21 is arrange | positioned).

  Due to the difference between the gap based on the distance DXa and the gap based on the distance DXb, the encoder device EC in this embodiment has an end portion 35a of the magnetic body 35 as compared with the case where the gap between the magnet 21 and the magnetic body 35 is uniform. The magnetic field acting on is relatively weak. In the encoder device EC according to the present embodiment, the magnetic field acting on the end portion 35a of the magnetic body 35 is weakened and the influence of the magnetic fields of the two end portions 35a (eg, cancellation of the magnetic field at the end portion 35a) is reduced. The large Barkhausen effect is stably generated in the magnetic body 35, and the detection signal is stably generated in the signal generation unit 31 (also described in FIG. 3).

  The coil section 36 is disposed around the magnetic body 35 (eg, near, around), and a detection signal is generated by electromagnetic induction accompanying the large Barkhausen effect generated in the magnetic body 35. The coil unit 36 includes, for example, a high density coil. Since the coil portion 36 is wound around the magnetic body 35, electromagnetic induction (induced electromotive force) is generated in the coil portion 36 with the occurrence of the domain wall in the magnetic body 35, and an induced current flows. The detection signal generated by the signal generator 31 includes one or both of an induced electromotive force and an induced current of electromagnetic induction generated in the coil unit 36. The detection signal includes, for example, a waveform in which power (induced current, induced electromotive force) changes with time.

  A pulsed current is generated in the coil portion 36 due to the large Barkhausen effect generated in the magnetic body 35. For example, when the magnetization directions in the magnetic body 35 are reversed all at once based on the rotation of the rotating body, the coil section 36 detects the change in the magnetic field at the reversed timing and outputs the detection signal. Therefore, the coil unit 36 can output the detection signal including a detection pulse such as a positive pulse or a negative pulse using the large Barkhausen effect, for example. The direction of the current generated in the coil section 36 changes according to the direction before and after the reversal of the magnetic field. The electric power (inductive current) generated in the coil unit 36 can be set by, for example, the number of turns of the high-density coil. The detection signal generated in the coil section 36 can be taken out through the terminal 37a and the terminal 37b. As described above, the coil section 36 can operate without power supply from the outside (for example, the power supply PW in FIG. 1).

  The signal generator 31 outputs a detection signal based on the angular position of the magnet 21. For example, a detection signal (electric signal) is generated in the signal generation unit 31 due to a change in the magnetic field formed by the magnet 21 used by the multi-rotation information detection unit 1A to detect the multi-rotation information of the rotating body SF. The signal generating unit 31 is arranged so that the relative angular position with the magnet 21 is changed by the rotation of the rotating body SF.

  For example, when the relative position between the signal generator 31 and the magnet 21 reaches a predetermined position (or a specific position), the signal generator 31 generates a pulse-like detection signal. The signal generation unit 31 can be used as a detection unit (a sensor of the position detection unit 1 or an alternative sensor of the position detection unit 1) that detects that the relative position to the magnet 21 has reached a predetermined position. In this case, for example, the encoder device EC includes a plurality of signal generators 31 arranged at mutually different positions (for example, angular positions such as 45 °, 90 °, and 180 ° around the rotation axis of the magnet 21), The angular position information and the multi-rotation information described above are calculated by the processing units (for example, the processing units 13 and 23) using the pulse-like detection signals respectively output from the plurality of signal generation units 31 based on the rotation of the magnet 21. Can do.

  As described above, the signal generation unit 31 according to the present embodiment can calculate the rotational position information of the rotating body SF in combination with the above-described position detection unit 1, and can configure a duplex detection unit to improve reliability. . The signal generator 31 of the present embodiment can calculate the rotational position information of the rotating body SF even in a configuration in which the encoder device EC does not include the position detector 1 described above. The detection result of the signal generator 31 includes the above detection signal.

  FIG. 3 is a diagram illustrating a magnetic field formed by the magnet according to the first embodiment. In FIG. 3, “angular position” is an angular position of the magnet 21 with the state of FIG. 2A as a reference (0 °). Here, the counterclockwise angular position is positive. At each angular position in FIG. 3, the magnetic field formed by the magnet 21 is represented by an arrow (vector). The direction of this arrow represents the direction of the magnetic field lines at each position. The size of this arrow represents the strength of the magnetic force at each position. On the left side of FIG. 3, the magnetic field is shown in the range where the “angular position” is 0 ° to 45 °. In addition, on the right side of FIG. 3, the magnetic field is shown in the range where the “angular position” is 45 ° to 90 °.

  In the state where the “angular position” is 0 °, the lines of magnetic force at the position of the central portion 35b (see FIG. 2) of the magnetic body 35 face the −Y side. As the “angular position” goes from 0 ° to 45 °, the strength of the lines of magnetic force at the position of the magnetic body 35 decreases. In the state where the “angular position” is 45 °, the strength of the magnetic field in the central portion 35b of the magnetic body 35 is almost zero. As the “angular position” moves from 45 ° to 90 °, the strength of the magnetic field lines at the position of the magnetic body 35 increases. In the state where the “angular position” is 90 °, the magnetic field lines at the position of the central portion 35b (see FIG. 2) of the magnetic body 35 face the + Y side. As described above, the direction of the magnetic force lines felt by the magnetic body 35 is reversed, so that a large Barkhausen effect is generated in the magnetic body 35 and a detection signal is generated in the coil section 36.

  In the present embodiment, since the signal generator 31 is disposed in the radial direction with respect to the magnet 21, for example, the central portion 35 a of the magnetic body 35 and the magnet 21 can be disposed close to each other. Therefore, the central portion 35a of the magnetic body 35 can detect, for example, the magnetic field formed by the magnetic body 21 with high accuracy and high sensitivity. Therefore, the signal generator 31 can stably generate the detection signal.

  The direction of the lines of magnetic force when the “angular position” is 45 ° is reversed between the + Y side end and the −Y side end of the magnetic body 35. If the direction of the lines of magnetic force is reversed in each part of the magnetic body 35, the generation of the large Barkhausen effect may not be stable. However, in the present embodiment, the end portion 35 a of the magnetic body 35 is disposed at a position farther from the magnet 21 than the central portion 35 b of the magnetic body 35. In this case, compared with the case where the magnetic body 35 is curved along the magnet 21, for example, the magnetic field acting on the end portion 35a of the magnetic body 35 is relatively weaker than that of the central portion 35b. The effect is stable. When the end portion 35a is farther from the magnet 21 than the central portion 35b, for example, a magnetic field contributing to the generation of the large Barkhausen effect can be applied to the central portion 36b more than the end portion 35a.

  The magnetic field acting on the end portion 35a when the end portion 35a is farther from the magnet 21 than the central portion 35b is more than the magnetic field acting on the end portion 35a when the magnetic body 35 is curved along the magnet 21. Also become weaker. Therefore, it is possible to reduce the influence of the case where the direction of the magnetic field is opposite between the + Y side end 35a and the -Y side end 35a. Therefore, the signal generator 31 stably generates the large Barkhausen effect and generates the detection signal stably.

  Returning to the description of FIG. 2, the magnet 21 forms a magnetic field in the direction of the rotation axis AX by the N pole 21 a and the S pole 21 b which are adjacent on the inner peripheral side and the outer peripheral side. This magnetic field includes a component parallel to the XY plane. The magnetic detection unit 22 (magnetic sensor 25, magnetic sensor 26) detects a magnetic field parallel to the XY plane. The magnetic sensor 25 and the magnetic sensor 26 are arranged so as to avoid the boundary between the N pole 21a and the S pole 21b of the magnet 21 at the timing when the detection signal is generated in the signal generating unit 31. For example, the signal generator 31 generates a detection signal when the magnet 21 is disposed at a predetermined angular position. Each of the magnetic sensor 25 and the magnetic sensor 26 is disposed at an angular position away from the boundary between the N pole 21a and the S pole 21b in the rotation direction when the magnet 21 is disposed at a predetermined angular position. The magnetic sensor 26 is disposed, for example, in a range of 90 ° or more and less than 180 ° with respect to the magnetic sensor 25 at an angular position about the rotation axis AX of the magnet 21.

  Returning to the description of FIG. 1, the switching unit 32 switches the presence / absence of power supply from the battery 33 to the position detection unit 1 using the detection signal generated by the signal generation unit 31 as a control signal. The position detection unit 1 receives power supply from the power supply unit 2 and starts detecting position information. The position detection unit 1 detects the rotational position information of the rotating body SF by the power supplied from the power supply unit 2 based on the detection signal generated by the signal generation unit 31.

  The detection signal generated by the signal generator 31 is used for the operation of at least a part of the position detector 1 (for example, the multi-rotation information detector 1A). For example, the power supply unit 2 supplies power used for the operation of the position detection unit 1 using the detection signal generated by the signal generation unit 31 in the backup state. For example, the position detection unit 1 (for example, the multi-rotation information detection unit 1A) performs the rotation position information detection operation by starting power supply based on the detection signal generated by the signal generation unit 31 in the backup state. Do.

  In the power supply unit 2, the battery 33 (battery) supplies at least a part of the power consumed by the position detection unit 1 based on the detection signal generated by the signal generation unit 31, for example. The battery 33 may include, for example, a primary battery such as a button-type battery or a dry battery, or a secondary battery such as a lithium ion secondary battery.

  The switching unit 32 starts supplying power from the battery 33 to the position detection unit 1 when the level of the detection signal generated by the signal generation unit 31 is equal to or higher than the threshold value. For example, the switching unit 32 starts supplying power from the battery 33 to the position detection unit 1 when the signal generation unit 31 generates a detection signal equal to or greater than the threshold value.

  The switching unit 32 stops the supply of power from the battery 33 to the position detection unit 1 when the level of the detection signal generated by the signal generation unit 31 becomes less than the threshold value. For example, when a pulsed detection signal is generated in the signal generation unit 31 in a state where the power supply from the power source PW is cut off (backup state), the switching unit 32 indicates that the level (potential) of the detection signal is low. From the battery 33, the supply of power from the battery 33 to the position detection unit 1 is started. After a predetermined time has elapsed since the level (potential) of the detection signal has changed to the low level, the battery 33 The supply of power to the position detection unit 1 is stopped.

  Next, an example of a circuit configuration of the encoder device according to the embodiment will be described. FIG. 4 is a diagram illustrating an example of a circuit configuration of the position detection unit and the power supply unit according to the first embodiment. The power supply unit 2 includes a rectifier stack 61 and a regulator 63 as the switching unit 32 in FIG.

  The rectification stack 61 is a rectifier that rectifies the current flowing from the signal generator 31. The first input terminal 61 a of the rectifying stack 61 is connected to the terminal 37 a of the signal generator 31. The second input terminal 61 b of the rectification stack 61 is connected to the terminal 37 b of the signal generator 31. The ground terminal 61g of the rectifying stack 61 is connected to a ground line GL to which the same potential as the signal ground SG is supplied. During the operation of the multi-rotation information detection unit 1A, the potential of the ground line GL becomes the reference potential of the circuit 60. The output terminal 61 c of the rectifying stack 61 is connected to the control terminal 63 c of the regulator 63.

  The regulator 63 adjusts the electric power supplied from the battery 33 to the position detection unit 1 according to the on state and the off state of the regulator 63. The regulator 63 includes a switch (for example, a switching element 64) provided in a power supply path between the battery 33 and the position detection unit 1. The regulator 63 controls the operation of the switching element 64 using the detection signal generated by the signal generator 31 as a control signal (eg, an enable signal).

  An input terminal 63 a of the regulator 63 is connected to the battery 33. The output terminal 63b of the regulator 63 is connected to the power supply line PL. The ground terminal 63g of the regulator 63 is connected to the ground line GL. The control terminal 63c of the regulator 63 is an enable terminal, and the regulator 63 maintains the potential of the output terminal 63b at a predetermined voltage in a state where a voltage higher than the threshold is applied to the control terminal 63c. The output voltage of the regulator 63 (the above-mentioned predetermined voltage) is, for example, 3 V when the counting unit 67 is configured by a CMOS or the like. The operating voltage of the storage unit 24 is set to the same voltage as a predetermined voltage, for example. The predetermined voltage is a voltage necessary for power supply, and may be a constant voltage value or a voltage that changes stepwise.

  The switching element 64 switches between conduction and interruption of the circuit 60 that supplies power to the position detection unit 1. For example, the circuit 60 forms a power supply path that connects a first electrode (positive electrode) and a second electrode (negative electrode) of a second power supply (eg, battery 33), and includes a power supply line PL and a ground line GL. For example, the ground line GL is connected to the negative electrode of the battery 33, and the potential thereof becomes the reference potential of the circuit 60. For example, the switching element 64 switches whether or not power is supplied from the battery 33 to the position detection unit 1 via the circuit 60.

  The regulator 63 uses the detection signal supplied from the signal generator 31 to the control terminal 63c as a control signal (enable signal), and conducts between the first terminal 64a and the second terminal 64b of the switching element 64 (ON). State) and insulation state (off state). For example, the switching element 64 includes a MOS, a TFT, etc., the first terminal 64a and the second terminal 64b are a source electrode and a drain electrode, and the control terminal 64c is a gate electrode.

  The switching element 64 switches the circuit 60 to conduction based on the voltage of the control terminal 64c generated by the detection signal generated by the signal generator 31. For example, the switching element 64 blocks the circuit 60 in a state where the potential of the control terminal 64 c is the reference potential of the circuit 60. Moreover, the switching element 64 will be in a conduction | electrical_connection state (on state) between the 1st terminal 64a and the 2nd terminal 64b because the voltage of the control terminal 64c becomes more than predetermined value. Switch circuit 60 to conduction. When the first terminal 64a and the second terminal 64b are turned on, power is supplied from the battery 33 to the circuit 60 via the power supply line PL and the ground line GL. The power supply unit 2 may include an acquisition unit that acquires the on state and the off state of the regulator 63.

  The multi-rotation information detection unit 1A includes an analog comparator 65, an analog comparator 66, and a counting unit 67 as the processing unit 23 illustrated in FIG. Each of the magnetic sensor 25 and the magnetic sensor 26 is a sensor that detects the rotating body SF. The magnetic sensor 25 and the magnetic sensor 26 detect the rotating body SF by detecting a magnetic field formed by the magnet 21 attached to the rotating body SF. Each of the magnetic sensor 25 and the magnetic sensor 26 detects the magnetic field formed by the magnet 21 using the power supplied from the battery 33.

  The power supply terminal 25p of the magnetic sensor 25 is connected to the power supply line PL. The ground terminal 25g of the magnetic sensor 25 is connected to the ground line GL. The output terminal 25 c of the magnetic sensor 25 is connected to the input terminal 65 a of the analog comparator 65.

  The analog comparator 65 is a binarization unit that binarizes the voltage output from the magnetic sensor 25. The analog comparator 65 is a comparator, for example, and compares the voltage output from the magnetic sensor 25 with a predetermined voltage. The power supply terminal 65p of the analog comparator 65 is connected to the power supply line PL. The ground terminal 65g of the analog comparator 65 is connected to the ground line GL. The output terminal 65 b of the analog comparator 65 is connected to the first input terminal 67 a of the counting unit 67. The analog comparator 65 outputs an H level signal from the output terminal when the output voltage of the magnetic sensor 25 is equal to or higher than the threshold value, and outputs an L level signal from the output terminal when the output voltage is lower than the threshold value.

  The magnetic sensor 26 and the analog comparator 66 have the same configuration as the magnetic sensor 25 and the analog comparator 65. The power supply terminal 26p of the magnetic sensor 26 is connected to the power supply line PL. The ground terminal 26g of the magnetic sensor 26 is connected to the ground line GL. The output terminal 26 c of the magnetic sensor 26 is connected to the input terminal 66 a of the analog comparator 66. The power supply terminal 66p of the analog comparator 66 is connected to the power supply line PL. The ground terminal 66g of the analog comparator 66 is connected to the ground line GL. The output terminal 66 b of the analog comparator 66 is connected to the second input terminal 67 b of the counting unit 67. The analog comparator 66 outputs an H level signal from the output terminal when the output voltage of the magnetic sensor 26 is equal to or higher than the threshold value, and outputs an L level signal from the output terminal 66b when the output voltage is lower than the threshold value.

  The counting unit 67 counts the multi-rotation information of the rotating body SF using the power supplied from the battery 33. The counting unit 67 includes, for example, a CMOS logic circuit. The counting unit 67 operates using electric power supplied via the power supply terminal 67p and the ground terminal 67g. The power supply terminal 67p of the counting unit 67 is connected to the power supply line PL. The ground terminal 67g of the counting unit 67 is connected to the ground line GL. The counting unit 67 performs a counting process using the voltage supplied via the first input terminal 67a and the voltage supplied via the second input terminal 67b as control signals.

  The storage unit 24 stores at least a part (for example, multi-rotation information) of the rotational position information detected by the processing unit 23 using electric power supplied from the battery 33 (performs a writing operation). The storage unit 24 stores the count result (multi-rotation information) by the counting unit 67 as the rotational position information detected by the processing unit 23. The power supply terminal 26p of the storage unit 24 is connected to the power supply line PL. The ground terminal 26g of the storage unit 24 is connected to the ground line GL. The storage unit 24 includes, for example, a non-volatile memory, and can hold information written while power is supplied even in a state where power is not supplied. Note that the multi-rotation information detection unit 1A may include means for acquiring the on state and the off state of the regulator 63.

  In the present embodiment, a capacitor 69 is provided between the rectifying stack 61 and the regulator 63. The first electrode 69 a of the capacitor 69 is connected to a signal line that connects the rectifying stack 61 and the control terminal 63 c of the regulator 63. The second electrode 69b of the capacitor 69 is connected to the ground line GL. The capacitor 69 is a smoothing capacitor, for example, and reduces pulsation to reduce the load on the regulator. The constant of the capacitor 69 is such that, for example, power supply from the battery 33 to the processing unit 23 and the storage unit 24 is maintained during a period from when the rotational position information is detected by the processing unit 23 until the rotational position information is written in the storage unit 24. Is set to

  In the encoder device EC according to the present embodiment, power is supplied from the battery 33 to the multi-rotation information detection unit 1A within a short time after the detection signal is generated in the signal generation unit 31, and the multi-rotation information detection unit 1A Dynamic drive (intermittent drive). After completion of the detection and writing of the multi-rotation information, the power supply to the multi-rotation information detection unit 1A is cut off, but the count value is stored because it is stored in the storage unit 24. Such a sequence is repeated every time a predetermined position on the magnet 21 passes in the vicinity of the signal generator 31 even in a state where the external power supply is cut off. The multi-rotation information stored in the storage unit 24 is read to the control unit MC, for example, when the drive device MTR is activated next time, and is used for calculating the initial position of the rotating body SF.

  In the encoder device EC as described above, the magnet 21 is magnetized in a direction crossing the rotation axis AX. For example, the magnet 21 is magnetized in a direction orthogonal to the rotation axis AX (in this case, a radial direction different from the axial direction). The signal generator 31 is disposed in a direction orthogonal to the rotation axis AX of the magnet 21. Therefore, the signal generation unit 31 is arranged close to the magnet 21, for example, and generates a detection signal stably. In addition, as shown in FIG. 2, when the end 35 a of the magnetic body 35 is arranged at a position farther from the magnet 21 than the center 35 b, the signal generator 31 has a magnetic field acting on the end 35 a, for example. By reducing the strength, the detection signal is stably generated.

  One or both of the incremental pattern INC and the absolute pattern ABS may be provided on the surface of the scale S opposite to the magnet 21 (shown later in FIG. 8A). Further, one or both of the incremental pattern INC and the absolute pattern ABS may be provided outside the position of the magnet 21 (shown later in FIG. 8B). Further, the magnet 21 may be provided on a first rotating body (for example, the scale S) provided with one or both of the incremental pattern INC and the absolute pattern ABS, and on a second rotating body different from the first rotating body (see FIG. 8 later). (B), shown in FIG. 8C).

  Note that the power supply unit 2 in this embodiment may supply the position detection unit 1 with power obtained by adjusting the voltage of the detection signal generated by the signal generation unit 31 with a regulator or the like. For example, the power supply unit 2 may supply the position detection unit 1 with the power obtained by adjusting the voltage of the detection signal using a regulator or the like and the power from the battery 33 in combination or switching. The power supply unit 2 may supply power without using the detection signal generated by the signal generation unit 31 in the backup state. For example, the power supply unit 2 may continuously supply power in the backup state. The power supply unit 2 may supply power to a part other than the multi-rotation information detection unit 1A (eg, at least a part of the angle detection unit 1B). The encoder device EC may not include the power supply unit 2.

  The signal generation unit 31 may be a detection unit that detects that the relative position to the magnet 21 is a predetermined position. In this case, the position detector 1 may detect the rotational position information using the detection result (detection signal) of the signal generator 31. For example, the position detection unit 1 may detect the rotational position information using the detection result (detection signal) of the signal generation unit 31 instead of the detection result of the magnetic detection unit 22. Further, the position detection unit 1 may detect the rotational position information using the detection result of the magnetic detection unit 22 and the detection result (detection signal) of the signal generation unit 31.

[Second Embodiment]
A second embodiment will be described. In the present embodiment, the same components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is omitted or simplified. FIG. 5 is a diagram illustrating an encoder device according to the second embodiment. In the present embodiment, the signal generator 31 is supported by a mold of the encoder device EC, for example.

  In the present embodiment, the rotating body SF rotates with respect to the fixed member BD1. The fixing member BD1 includes, for example, a stator in the driving device MTR or a body to which the stator is fixed. The encoder device EC includes a first support member 41 and a second support member 42 as an encoder main body. The first support member 41 supports at least a part of the detection unit (position detection unit 1 in FIG. 1). For example, the first support member 41 supports one or both of the magnetic detection unit 22 and the detection unit 12.

  The first support member 41 includes a substrate (processing substrate) on which a processing circuit that processes the detection results of the detection units (the magnetic detection unit 22, the detection unit 12, and the signal generation unit 31) is provided. For example, the first support member 41 supports at least a part of the processing unit 23, the storage unit 24, the processing unit 13, the combining unit 27, and the switching unit 32 illustrated in FIG.

  The second support member 42 is disposed between the fixed member BD1 and the first support member 41 along the direction of the rotation axis AX. The second support member 42 is, for example, a mold or a spacer. The second support member 42 may be made of, for example, a resin, or may be made of an insulating metal (eg, anodized aluminum) at least on the surface.

  The second support member 42 defines a gap between the detection unit (the magnetic detection unit 22 and the detection unit 12) and the rotating body SF between the fixed member BD1 and the first support member 41. For example, the scale S (rotating body) is fixed to the rotating body SF, and the second support member 42 defines a gap in the Z direction between the incremental pattern INC and the absolute pattern ABS in the scale S and the detection unit 12. Moreover, the magnet 21 (rotating body) is fixed to the rotating body SF via the scale S, and the second support member 42 defines a gap in the Z direction between the magnet 21 and the magnetic detection unit 22.

  The second support member 42 is, for example, a cylindrical member that surrounds the scale S (or the magnet 21) in an annular shape. The second support member 42 has, for example, a ring shape when viewed from the rotation axis. The first support member 41 is provided so as to block the opposite side of the second support member 42 from the fixing member BD1. The first support member 41 is fixed to the fixing member BD1 by a fixing member 43 such as a bolt. The fixing member 43 is fixed to the fixing member BD1 of the driving device MTR through the through hole 44 provided in the second support member 42. The second support member 42 is sandwiched (fastened together) between the first support member 41 and the fixing member BD1, and is fixed to each of the first support member 41 and the fixing member BD1. Thus, the second support member 42 is fixed to the fixing member BD1 and the first support member 41 via the fixing member 43.

  The scale S is accommodated in a space SP1 surrounded by the fixing member BD1, the first support member 41, and the second support member. The second support member 42 is disposed so as to cover at least a part of the detection unit (position detection unit 1). At least a part of the position detection unit 1 is accommodated in the space SP1. Here, as shown in FIG. 5, the second support member 42 in the present embodiment is configured such that at least a part of the signal generator 31 is formed between the inner periphery 42 a (inner edge) and the outer periphery 42 b (outer edge) of the second support member 42. Accommodate in between. For example, the second support member 42 has an internal space SP2 (see FIGS. 5A and 5B) between the inner periphery 42a and the outer periphery 42b, and accommodates the signal generator 31 in the internal space SP2.

  In this way, the second support member 42 seals and fixes the signal generator 31 in the internal space SP2. The internal space SP2 of the second support member 42 has a shape such as a hollow shape, a cylindrical shape, a cavity, a concave portion, a groove, or a hole. Furthermore, for example, the internal space SP2 may be formed by one member of the second support member 42, or may be formed by two members of the second support member 42 and another member. Further, for example, in the present embodiment, the internal space SP2 may be filled with a resin or the like after the signal generating unit 31 is accommodated therein. In this case, the signal generator 31 is embedded in the internal space SP <b> 2 of the second support member 42.

    5B, at least a part of the magnetic body 35 is disposed at substantially the same position (eg, height position) as the magnet 21 in the direction parallel to the rotation axis AX (Z direction). The magnetic body 35 may be disposed on the side closer to the fixing member BD1 of the driving device MTR than the magnet 21 (−Z side). Further, the magnetic body 35 may be disposed on the side farther from the fixing member BD1 of the driving device MTR than the magnet 21 (+ Z side).

  The first support member 41 and the second support member 42 are provided with through holes 45 (see FIG. 5B). Inside the through hole 45, a conductive member 46 (eg, via, wiring) that is electrically connected to the coil portion 36 of the signal generating unit 31 is disposed. The conductive member 46 includes a terminal 37a and a terminal 37b, and the terminal 37a and the terminal 37b of the signal generating unit 31 are disposed on the surface 41a of the first support member 41, for example. The surface 41 a is a surface facing the opposite side of the scale S in the first support member 41. The surface 41 a is a surface on the opposite side to the surface on which the irradiation unit 11 and the detection unit 12 are arranged in the first support member 41. In the first support member 41, a surface 41b opposite to the surface 41a is a surface facing the scale S, for example. The surface 41 b is a surface facing the irradiation unit 11 and the detection unit 12.

  The terminal 37 a and the terminal 37 b are electrically connected to the coil portion 36 through the conductive member 46. For example, the terminals 37a and 37b are electrically connected to terminals (board-side terminals) provided on the first support member 41 by solder or the like.

  As described above, the signal generator 31 according to the present embodiment is supported by the second support member 42 between the fixing member BD1 and the first support member 41. In the present embodiment, the signal generator 31 is accommodated and fixed in at least a part of the second support member 42 (for example, an internal space). Therefore, the encoder device EC can support the signal generating unit 31 by using the space between the fixing member BD1 and the first support member 41, for example, and can save space. Further, the encoder device EC can reduce the number of parts by using, for example, a mold or a spacer as the second support member 42.

  The second support member 42 may be provided locally, discontinuously, or discretely in the rotation direction of the rotation axis AX. Further, the shape of the second support member 42 may not be cylindrical, and for example, the shape of the rotational axis view may be a polygonal frame shape (eg, a square frame shape). The second support member 42 may not seal at least a part of the signal generation unit 31 (eg, the magnetic body 35 and the coil unit 36). For example, the internal space SP2 of the second support member 42 may communicate with the space SP1. At least a part of the signal generating unit 31 (for example, the magnetic body 35 and the coil unit 36) may be exposed to the space SP1.

  One or both of the terminal 37a and the terminal 37b of the signal generating unit 31 may not be disposed on the surface 41a of the first support member 41. For example, the terminal of the first support member 41 is disposed on the surface 41b, and one or both of the terminal 37a and the terminal 37b of the signal generator 31 are electrically connected to the terminal of the first support member 41 on the surface 41b. Also good. In addition, one or both of the terminal 37a and the terminal 37b of the signal generation unit 31 may be electrically connected to the terminal of the first support member 41 by a method (eg, contact) other than solder.

  Next, a modification according to the embodiment will be described. FIG. 6 is a diagram illustrating the magnet according to the embodiment. The magnet 21 shown in FIG. 6 is locally magnetized in the rotation direction. The magnet 21 includes a plurality of magnetized portions 51. The plurality of magnetized portions 51 are discretely provided at regular intervals in the rotation direction of the rotation axis AX. The intermediate part 52 between the magnetized parts 51 adjacent to each other in the rotation direction of the rotation axis AX is a neutral part that is weaker than the magnetized part 51. The magnet 21 having such an intermediate portion 52 can reduce the strength of the magnetic field acting on both end portions of the magnetic body 35 at the angular positions where the magnetic field directions are different at both end portions of the magnetic body 35. Therefore, as described with reference to FIG. 3, for example, the large Barkhausen effect is stably generated in the magnetic body 35, and the detection signal is stably generated in the signal generator 31.

  The magnet 21 in FIG. 6A includes, for example, a radially anisotropic magnetized magnet. In the magnet 21, the N pole 21 a and the S pole 21 b are aligned in the rotation direction of the rotation axis AX in the magnetized portion 51. In the magnet 21, the N pole 21 a and the S pole 21 b are arranged in the radial direction in the magnetized portion 51. The magnet 21 in FIG. 6B includes, for example, a polar anisotropic magnet. Note that the magnet 21 according to the embodiment may have a magnetic field strength in the axial direction that is weaker than a magnetic field strength in the rotation direction. For example, when the position detection unit 1 includes a magnetic encoder, the magnetic detection unit 22 may be arranged in the radial direction with respect to the magnet 21 similarly to the signal generation unit 31.

  FIG. 7 is a diagram illustrating a modification of the magnet according to the embodiment. In the magnet 21 shown in FIG. 7A, the magnetized portion 51 and the intermediate portion 52 are separate members. The intermediate part 52 is, for example, a nonmagnetic material or a member having a lower magnetic permeability than the magnetized part 51. For example, the magnet 21 is formed by fixing (eg, integrating) the magnetized portion 51 and the intermediate portion 52. The magnet 21 may be formed by magnetizing the above-described base material after fixing the base material which is the magnetized portion 51 before the magnetization and the intermediate portion 52.

  A magnet 21 shown in FIG. 7B includes a base member 53 and a magnetized portion 51. The base member 53 is, for example, a disk-shaped member (for example, a substrate), and rotates in the rotation direction based on the rotation of the rotation axis AX. The magnetized portion 51 is fixed to the base member 53. The magnetized portions 51 are discretely arranged at specific intervals in the rotation direction. The intermediate part 52 of the magnetized parts 51 adjacent in the rotation direction is, for example, a gap (atmosphere gas). Moreover, the magnetized portion 51 of the magnet 21 shown in FIG. 7C is a bar magnet and is discretely arranged at specific intervals in the rotation direction. For example, the magnet 21 includes four pairs of bar magnets arranged at equal intervals in the rotation direction.

  FIG. 8 is a diagram illustrating the encoder device according to the embodiment. In FIG. 8A, the incremental pattern INC and the absolute pattern ABS are arranged on the surface Sa (pattern surface, one surface) of the scale S. The surface Sa is a surface facing the first support member 41, for example. The detection unit 12 is supported by the first support member 41 and is disposed so as to face the incremental pattern INC and the absolute pattern ABS.

  The magnet 21 is arranged on the surface Sb (the other surface) opposite to the surface Sa in the scale S. At least a part of the magnet 21 is disposed, for example, at a position overlapping with the incremental pattern INC or the absolute pattern ABS in the axial direction view. The magnet 21 may be arranged at a position that does not overlap the incremental pattern INC or the absolute pattern ABS in the axial direction view.

  The magnetic detection unit 22 of this embodiment is supported by a third support member 55 that is different from the first support member 41. The third support member 55 is fixed to the second support member 42 at one end, for example. For example, the third support member 55 rotatably supports the scale S by a bearing 55a at the other end. Note that the third support member 55 may be fixed to the fixing member BD1 of the driving device MTR. Further, the third support member 55 may not support the scale S.

  The incremental pattern INC and the absolute pattern ABS may be arranged on the surface Sb of the scale S. In this case, the detection unit 12 may be supported by the third support member 55. Further, the magnet 21 may be disposed on the surface Sa of the scale S. In this case, the magnetic detection unit 22 may be supported by the first support member 41. In these cases, the magnet 21, the incremental pattern INC, and the absolute pattern ABS are arranged on the same surface (eg, surface Sa, surface Sb) side of the scale S, and the magnetic detection unit 22 and the detection unit 12 face the scale S. The first support member 41 or the third support member 55 are arranged on the same side (for example, the side of the surface 41b).

  In FIG. 8B, the encoder device EC includes a rotating member 56. The rotating member 56 is fixed to the scale S and rotates together with the scale S. The rotating member 56 is disposed on the same side as the first support member 41 with respect to the scale S. For example, the rotating member 56 is smaller than the scale S in the radial direction. The magnet 21 is provided on the rotating member 56. In this case, the magnet 21 is arranged inside the incremental pattern INC and the absolute pattern ABS in the radial direction. The detection unit 12 is supported by the third support member 55 outside the magnet 21 in the radial direction. The detection unit 12 may be supported by the first support member 41. The magnetic detection unit 22 is supported by the first support member 41 and is disposed so as to face the magnet 21.

  The signal generator 31 may be supported by a member different from the second support member 42. In FIG. 8B, the signal generator 31 is supported by the first support member 41. For example, the signal generating unit 31 includes a case 57 that supports the magnetic body 35 and the coil unit 36. The case 57 accommodates the magnetic body 35 and the coil portion 36 and is fixed to the first support member 41. In addition, as shown in FIG. 8C, at least a part of the signal generation unit 31 may be embedded in the internal space of the first support member 41. For example, the case 57 may be disposed in a hole 58 (eg, a bottomed depression or a through hole) formed in the first support member 41 as an internal space, and may be fixed to the first support member 41.

  The signal generator 31 may be supported by a member (eg, the third support member 55) different from the first support member 41. The signal generator 31 may be supported by the second support member 42. For example, the second support member 42 may have a protrusion protruding inward in the radial direction like the third support member 55, and the signal generator 31 may be supported by the protrusion of the second support member 42. . In this case, the signal generator 31 may not be accommodated in the second support member 42.

  FIG. 9 is a diagram illustrating a signal generation unit according to the embodiment. 9A, in the signal generating unit 31, the magnetic body 35 is curved based on the shape of the magnet 21 (eg, the shape of the side surface 21c). The magnetic body 35 is curved so as to follow the rotation direction of the magnet 21 (or the rotating body SF). The magnetic body 35 may be curved along the rotation direction of the rotating body SF. The curvature of the magnetic body 35 may be smaller than the curvature of the magnet 21 (the radius of curvature may be large). Further, the magnetic body 35 may be curved so as to be convex with respect to the magnet 21. The center of curvature of the magnetic body 35 may be disposed on the opposite side of the magnet 21 with respect to the magnetic body 35. Further, as illustrated in FIG. 9B, the encoder device EC may include a plurality of signal generation units 31. The number of signal generators 31 may be one as shown in FIG. 1, two as shown in FIG. 9B, or three or more. As described above, the signal generation unit 31 in the present embodiment is configured so that the magnet 21 is in the first direction (eg, the orthogonal radial direction) that intersects the rotation axis direction of the magnet 21 (in this case, the axial direction of the rotation axis AX). A magnetic field (magnetic field) formed by the magnet 21 that is arranged to face at least a part of the magnet and magnetized in the first direction is detected.

[Driver]
Next, the drive device according to the embodiment will be described. FIG. 10 is a diagram illustrating the drive device according to the embodiment. In the following description, components that are the same as or equivalent to those in the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted or simplified. The drive device MTR is a motor device including an electric motor. The driving device MTR includes a rotating body SF, a main body BD (driving unit) that rotationally drives the rotating body SF, and an encoder device EC that detects rotational position information of the rotating body SF.

  The rotating body SF has a load side end portion SFa and an anti-load side end portion SFb. The load side end portion SFa is connected to another power transmission mechanism such as a speed reducer. The scale S described above is fixed to the non-load side end portion SFb. The encoder device EC is the encoder device according to the above-described embodiment. Further, the power transmission mechanism connected to the load side end portion SFa is connected to an arm such as a robot apparatus via a rotating body (eg, FIG. 12).

  In the driving device MTR, the control unit MC shown in FIG. 1 and the like controls the main body BD using the detection result of the encoder device EC. The drive device MTR can operate stably, for example, when the detection signal is stably generated in the signal generator 31 of the encoder device EC. Further, the drive device MTR can reduce the maintenance cost because, for example, there is no need or low battery replacement of the encoder device EC. The drive device MTR is not limited to a motor device, and may be another drive device having a shaft portion that rotates using hydraulic pressure or pneumatic pressure. When the drive device MTR includes the power transmission mechanism and the encoder device EC according to the present embodiment, the encoder device EC includes a plurality (in this case, two) of position detection units 1 and a plurality of (in this case, two) electric power. It is good also as a double encoder type device provided with supply part 2. In this case, for example, one of the two position detection units 1 detects rotation position information of the rotating body SF, and the other of the two position detection units 1 detects rotation position information of the rotating body of the power transmission mechanism.

[Stage device]
Next, the stage apparatus according to the embodiment will be described. FIG. 11 is a diagram illustrating a stage apparatus according to the embodiment. In the following description, components that are the same as or equivalent to those in the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted or simplified.

  This stage apparatus STG has a configuration in which a stage (a rotary table TB, a moving body, and a rotating body) is attached to a load-side end portion SFa of the rotating body SF of the driving apparatus MTR shown in FIG. The stage apparatus STG may have a configuration in which the stage is linearly moved in one direction by a one-dimensional linear motor, for example. Further, the stage apparatus STG may be configured to move the stage in two directions by a plurality of one-dimensional linear motors or two-dimensional linear motors (eg, planar motors).

  The stage device STG drives the driving device MTR to rotate the rotating body SF. This rotation is transmitted to the rotary table TB, and the encoder device EC detects the angular position and the like of the rotating body SF at that time. By using the output from the encoder device EC, the angular position of the rotary table TB can be detected. A reduction gear or the like may be disposed between the load side end SFa of the drive device MTR and the rotary table TB.

  The stage device STG can operate stably, for example, when the detection signal is stably generated in the signal generator 31 of the encoder device EC. Further, the stage device STG can reduce the maintenance cost because, for example, the necessity of replacing the battery of the encoder device EC is low or absent. The stage apparatus STG can be applied to a rotary table provided in a machine tool such as a lathe.

[Robot equipment]
Next, the robot apparatus according to the embodiment will be described. FIG. 12 is a diagram illustrating the robot apparatus according to the embodiment. FIG. 12 schematically shows a part (joint portion) of the robot apparatus RBT. In the following description, the same or equivalent components as those of the above-described embodiment are denoted by the same reference numerals, and the description is omitted or simplified. The robot apparatus RBT includes a first arm AR1, a second arm AR2, and a joint portion JT. The first arm AR1 is connected to the second arm AR2 via the joint portion JT.

  The first arm AR1 includes an arm portion 101, a bearing 101a, and a bearing 101b. The second arm AR2 has an arm portion 102 and a connection portion 102a. The connecting portion 102a is disposed between the bearing 101a and the bearing 101b in the joint portion JT. The connection part 102a is provided integrally with the rotating body SF2. The rotating body SF2 is inserted into both the bearing 101a and the bearing 101b in the joint portion JT. The end of the rotating body SF2 on the side inserted into the bearing 101b passes through the bearing 101b and is connected to the speed reducer RG.

  The reduction gear RG is connected to the drive device MTR, and reduces the rotation of the drive device MTR to, for example, 1/100 and transmits it to the rotating body SF2. The load-side end portion SFa of the rotating body SF of the drive device MTR is connected to the speed reducer RG. In addition, the scale S of the encoder device EC is attached to the anti-load side end portion SFb of the rotating body SF of the drive device MTR.

  When the robot apparatus RBT drives the driving apparatus MTR to rotate the rotating body SF, the rotation is transmitted to the rotating body SF2 via the reduction gear RG. Due to the rotation of the rotating body SF2, the connecting portion 102a rotates integrally, whereby the second arm AR2 rotates relative to the first arm AR1. At that time, the encoder device EC detects the angular position and the like of the rotating body SF. Therefore, the angular position of the second arm AR2 can be detected by using the output from the encoder device EC.

  The robot apparatus RBT can operate stably, for example, when the detection signal is stably generated in the signal generation unit 31 of the encoder apparatus EC. The robot apparatus RBT can reduce the maintenance cost because, for example, there is no need or low battery replacement of the encoder apparatus EC. The robot apparatus RBT is not limited to the above configuration, and the drive apparatus MTR can be applied to various robot apparatuses having joints.

  The technical scope of the present invention is not limited to the aspects described in the above-described embodiments. One or more of the requirements described in the above embodiments and the like may be omitted. In addition, the requirements described in the above-described embodiments and the like can be combined as appropriate. In addition, as long as it is permitted by law, the disclosure of all documents cited in the above-described embodiments and the like is incorporated as a part of the description of the text.

DESCRIPTION OF SYMBOLS 1 ... Position detection part (detection part), 2 ... Electric power supply part, S ... Scale, 13 ... Processing part, 21 ... Magnet. 21c ... side face, 22 ... magnetic detection part (detection part), 23 ... processing part, 24 ... storage part, 31 ... signal generation part, 35 ... magnetic body, 35a ... -End part, 35b ... Center part, 36 ... Coil part, 41 ... First support member, 42 ... Second support member, AX ... Rotating shaft, EC ... Encoder device, SF ... Rotating body, TB ... Rotary table (stage), 101 ... Arm, BD1 ... Fixed member, MTR ... Driving device, RBT ... Robot device, STG ... Stage apparatus

Claims (21)

A detection unit for detecting rotational position information of the rotating body;
A magnet that rotates relative to the detector;
A signal generator that is arranged in a direction perpendicular to the rotation axis of the rotating body with respect to the magnet and generates a detection signal by a large Barkhausen effect based on a change in a magnetic field formed by the magnet,
The encoder device, wherein the magnet is magnetized in a direction orthogonal to the rotation axis. The signal generator is
A magnetic material that produces the large Barkhausen effect by a change in the magnetic field formed by the magnet;
The encoder apparatus according to claim 1, further comprising: a coil unit that generates the detection signal by the large Barkhausen effect.   The encoder device according to claim 2, wherein an end portion in the easy magnetization direction of the magnetic body is disposed at a position farther from the magnet than a central portion of the magnetic body. The magnet is disposed along the rotation direction of the rotating body,
The encoder device according to claim 2, wherein the magnetic body is disposed so as to extend in a tangential direction of the outer periphery of the rotating body.   The encoder device according to any one of claims 1 to 4, wherein the magnet forms a magnetic field in a rotation direction of the rotation shaft.   The encoder device according to any one of claims 1 to 5, wherein the magnets are provided discretely in a rotation direction of the rotating body.   The encoder device according to any one of claims 1 to 5, wherein the magnet has four or more magnetic poles in a rotation direction of the rotating body.   The encoder device according to any one of claims 1 to 7, wherein the magnet includes a radially anisotropic magnetized magnet or a polar anisotropic magnetized magnet.   The encoder device according to any one of claims 1 to 8, wherein the magnet has a side surface that curves along a rotation direction of the rotating body. The rotating body rotates relative to a fixed member;
A first support member that supports at least a part of the detection unit;
The encoder device according to claim 1, further comprising: a second support member that is disposed between the fixing member and the first support member and supports the signal generation unit. A processing unit for processing the detection result of the detection unit,
The encoder device according to claim 10, wherein the first support member includes a substrate on which the processing unit is provided.   The encoder device according to claim 10 or 11, wherein the second support member accommodates at least a part of the signal generator between an inner periphery and an outer periphery of the second support member.   The encoder according to any one of claims 10 to 11, wherein the second support member defines a gap between the detection member and the rotating body between the fixing member and the first support member. apparatus.   The encoder device according to any one of claims 10 to 13, wherein the second support member is fixed to each of the first support member and the fixing member.   The encoder device according to any one of claims 10 to 14, wherein the second support member is disposed so as to cover at least a part of the detection unit.   The encoder device according to any one of claims 10 to 15, wherein the second support member is annularly surrounded with respect to the magnet.   The encoder device according to any one of claims 1 to 16, wherein the detection unit includes a multi-rotation information detection unit that detects multi-rotation information of the rotating body based on a magnetic field formed by the magnet.   The encoder apparatus according to any one of claims 1 to 17, further comprising a power supply unit that supplies power to the detection unit based on the detection signal. The encoder device according to any one of claims 1 to 18,
And a driving unit that supplies a driving force to the rotating body. A drive device according to claim 19,
And a stage that is moved by the driving device. A drive device according to claim 19,
And an arm that is moved by the driving device.

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