JP7024207B2 - Encoder device, drive device, stage device, and robot device - Google Patents

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, an encoder device is required to efficiently detect a magnetic field of a magnet.

Japanese Unexamined Patent Publication No. 8-50034

In the embodiment of the present invention, a detection unit that detects the rotation position information of the rotating body, a magnet that rotates relative to the detection unit, and a magnet arranged in a direction orthogonal to the rotation axis of the rotating body with respect to the magnet. A magnet is provided with a signal generation unit that generates a detection signal by a large bulkhausen effect based on a change in the magnetic field formed by the magnet, and a support member that supports the signal generation unit and accommodates at least a part of the signal generation unit. Is magnetized in a direction orthogonal to the axis of rotation and includes a first support member that supports at least a part of the detection unit, the rotating body rotates with respect to the fixing member, and the support member is the fixing member and the first. The second support member is a second support member arranged between the first support member, and the second support member is provided by an encoder device that defines a gap between a detection unit and a rotating body between the fixing member and the first support member. Will be done.
Further, in the embodiment of the present invention, a detection unit that detects the rotation position information of the rotating body, a magnet that rotates relative to the detection unit, and a magnet arranged in a direction orthogonal to the rotation axis of the rotating body with respect to the magnet. It is provided with a signal generation unit that generates a detection signal by a large bulkhausen effect based on a change in the magnetic field formed by the magnet, and a support member that supports the signal generation unit and accommodates at least a part of the signal generation unit. The magnet is magnetized in a direction orthogonal to the axis of rotation and includes a first support member that supports at least a part of the detection unit, the rotating body rotates with respect to the fixing member, and the support member is a fixing member. A second support member arranged between the first support member and the first support member, the second support member is provided with an encoder device fixed to each of the first support member and the fixing member.
Further, in the embodiment of the present invention, a detection unit that detects the rotation position information of the rotating body, a magnet that rotates relative to the detection unit, and a magnet arranged in a direction orthogonal to the rotation axis of the rotating body with respect to the magnet. It is provided with a signal generation unit that generates a detection signal by a large bulkhausen effect based on a change in the magnetic field formed by the magnet, and a support member that supports the signal generation unit and accommodates at least a part of the signal generation unit. The magnet is magnetized in a direction orthogonal to the axis of rotation and includes a first support member that supports at least a part of the detection unit, the rotating body rotates with respect to the fixing member, and the support member is a fixing member. It is a second support member arranged between the first support member and the first support member, and the second support member defines a gap between the detection unit and the rotating body between the fixing member and the first support member, and is the first. An encoder device is provided that is fixed to each of the support member and the fixing member.
Further, in the first aspect of the present invention, an encoder device is provided. The encoder device includes a detection unit that detects rotation position information of a rotating body. The encoder device includes a magnet that rotates relative to the detector. The encoder device is arranged in a direction orthogonal to the rotation axis of the rotating body with respect to the magnet, and includes a signal generation unit that generates a detection signal by a large Barkhausen effect based on a change in the magnetic field formed by the magnet. The encoder device includes a support member that supports the signal generation unit and accommodates at least a part of the signal generation unit. The magnet is magnetized in a direction orthogonal to the axis of rotation.

In the second aspect of the present invention , a drive device is provided. The drive device comprises the encoder device of the first aspect. The drive device includes a drive unit that supplies a drive force to the rotating body .

In the third aspect of the present invention , a stage device is provided. The stage device comprises the drive device of the second aspect. The stage device includes a stage that is moved by a drive device .

In a fourth aspect of the invention , a robotic device is provided. The robot device includes the drive device of the second aspect. The robot device includes an arm that is moved by a drive device .

It is a figure which shows the encoder device which concerns on 1st Embodiment. It is a figure which shows the magnet and the signal generation part which concerns on 1st Embodiment. It is a figure which shows the magnetic field formed by the magnet which concerns on 1st Embodiment. It is a figure which shows the circuit structure of the position detection part and the power supply part which concerns on 1st Embodiment. It is a figure which shows the encoder device 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 device 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]
The first embodiment will be described. FIG. 1 is a diagram showing an encoder device according to the first embodiment. The encoder device EC detects the position information (movement information) of the 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 above-mentioned position information includes rotation position information. In the following description, the direction parallel to the rotation axis AX of the rotating body SF is referred to as an axial direction, and the 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 rotating 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 (eg, an object interlocking with an armature, a shaft, a rotor) in a drive device MTR such as an electric motor. The rotating body SF may be an action shaft connected to the output shaft of the drive device MTR. The above-mentioned working axis includes, for example, an output shaft of the drive device MTR and a shaft connected via a transmission.

The above rotation position information includes one or both of the multi-rotation information and the angle position information. The multi-rotation information includes information indicating the number of rotations (eg, 1 rotation, 2 rotations, multi-rotation). 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 above rotation position information includes multi-rotation information and angular position information.

The drive device MTR includes, for example, a main body unit 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 armature of an electric motor. Stator includes, for example, magnets of electric motors (eg, permanent magnets). The body houses the rotor and stator. The stator is fixed to the body and the rotor is rotatably supported with respect to the body.

The rotor is rotated with respect to the stator by the electric power supplied from the power supply PW. The power supply PW (first power supply) is, for example, the main power supply 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 drive of the rotating body SF based on the rotation position information detected by the encoder device EC. For example, the control unit MC controls the electric power supplied from the power supply PW as the electric power consumed for the rotation of the rotor based on the rotation position information. The control unit MC controls the electric power supplied to the main body unit BD so that at least one of the angular position, the angular velocity, and the angular acceleration of the rotor approaches the target value, for example.

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 the rotation 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 the multi-rotation information of the rotating body SF. The angle detection unit 1B detects the angle position of the rotating body SF.

The angle detection unit 1B detects position information (angle 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. Although the angle detection unit 1B includes an optical encoder in this embodiment, it 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, for example, a disk-shaped member. 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, for example, on the surface Sa of the scale S. One or both of the incremental pattern INC and the absolute pattern ABS may be provided on the surface Sb opposite to the surface Sa on the scale S.

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

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

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

The multi-rotation information detection unit 1A detects the angle 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 also 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 (eg, a part of the position detection unit 1). For example, the magnet 21 rotates relative to the magnetic detection unit 22 due to 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 together with the rotating body SF, and the magnet 21 rotates in conjunction with the rotating body SF. Further, the magnet 21 is arranged in a direction intersecting the rotation axis direction of the rotation axis AX of the rotating body SF. In this embodiment, the magnet 21 is arranged along the radial direction. The magnet 21 is, for example, a ring-shaped member. 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.

The magnet 21 is provided, for example, on the surface Sa on the same side as the incremental pattern INC and the absolute pattern ABS on the scale S. The magnet 21 is arranged outside the incremental pattern INC and the absolute pattern ABS in the radial direction, for example, 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 an external member of 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 with the rotation of the rotating body SF. The magnetic detection unit 22 detects the 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 for the A-phase signal and the detection result of the magnetic sensor 26 for 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 the position information detected and processed by the processing unit 23 based on the storage command (data writing command) of the 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 that of the magnetic detection unit 22. For example, the magnet 21 may be provided at a position where the magnet 21 rotates relative to the magnetic detection 22 provided on the scale S due to the rotation of the scale S.

In the present embodiment, the encoder device EC includes a synthesis unit 27. The synthesizing unit 27 acquires the angle position information of the second resolution detected by the processing unit 13. Further, the synthesis 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 synthesizing unit 27 synthesizes the angle position information from the processing unit 13 and the multi-rotation information from the multi-rotation information detection unit 1A, and calculates the rotation 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 the rotation position information. Is calculated. The rotation position information may be information that is a set of multi-rotation information and angle position information.

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

The encoder device EC detects the rotation position information of the rotating body SF in each of the normal state and the backup state in which the power supply sources of the power consumed by the encoder device EC are different. The above normal states include a state in which the power supply PW is turned on, a state in which the power supply PW is turned on, a state in which power is supplied from the power supply PW to the device on which the encoder device EC is mounted, and a state in which the power supply PW is supplied. It includes at least one state in which power is supplied from the power supply PW to the encoder device EC. The above backup state is, for example, a state in which the power of the power supply PW is not turned on, a state in which the power supply PW is turned off, and a state in which power is not supplied from the power supply PW to the device on which the encoder device EC is mounted. , At least one state in which power is not supplied from the power supply PW to the encoder device EC is included.

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

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

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

The angle detection unit 1B does not detect (calculate) the angle information, for example, in the backup state in which the 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 the command of the control unit MC. The angle detection unit 1B is, for example, in a state where the power supply is cut off in the backup state, and does not detect the angle 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 31 is arranged 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) orthogonal to the rotation axis of the magnet 21 with respect to the magnet 21. The signal generation unit 31 is arranged, for example, 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 generation unit 31 due to the rotation of the rotating body SF. The magnetic field formed by the magnet 21 at the position of the signal generation unit 31 changes due to the relative rotation of the magnet 21 and the signal generation unit 31. The signal generation unit 31 generates a detection signal (electric signal) by the large Barkhausen effect based on the change in the magnetic field formed by the magnet 21. The power supply unit 2 supplies electric power based on the detection signal generated by the signal generation unit 31.

FIG. 2 is a diagram showing a magnet and a signal generation unit according to the first embodiment. In the following description, the XYZ Cartesian coordinate system shown in FIG. 2 and the like will be referred to as appropriate. In this XYZ Cartesian 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 seen from the Z direction is appropriately referred to as a rotation axis view. Further, in 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-shaped member whose thickness direction is parallel to the rotation axis AX. The magnet 21 is magnetized in the radial direction intersecting (eg, orthogonal to) its thickness direction. The orientation of the magnet 21 is set so that a magnetic field including a component in a direction perpendicular to the axis of rotation 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 outside the magnet 21 (eg, to 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. Further, 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, for example, 4 or more.

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

The angle position of the N pole 21a is 90 ° deviated between the inner peripheral side and the outer peripheral side. The angular positions of the S pole 21b are offset 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 to each other in the rotation direction. For example, the field line M1 from the N pole 21a on the outer peripheral side of the magnet 21 is 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 signal generation unit 31 relates to the radial direction (rotation axis AX). In the radial direction), it is arranged outside the magnet 21. The signal generation unit 31 is arranged at a position facing the side surface 21c of the magnet 21, for example. At least a part of the signal generation unit 31 is arranged at a position farther from the rotation axis AX than the magnet 21. For example, the signal generation unit 31 is arranged so as not to overlap the magnet 21 in the rotation axis view. The signal generation unit 31 may be arranged at a position overlapping a part of the magnet 21 in the rotation axis view.

The signal generation unit 31 includes a magnetic material 35 and a coil unit 36. The magnetic body 35 produces a large Bulk Hausen effect (also referred to as a large Bulk Hausen jump, a Weegand effect, or a Bulk Hausen effect) due to a change in the magnetic field formed by the magnet 21. The magnetic body 35 is a magnetically sensitive portion that senses a magnetic force. The magnetic body 35 is a magnetic sensitive wire such as a composite magnetic wire, a Wiegand wire, and an amorphous magnetic alloy wire. The large Barkhausen effect includes the movement of the domain wall inside the magnetic material at one time when the magnetic material is magnetized. The reference numeral Px in FIG. 2A indicates a position closest to the magnetic body 35 on the circumference (eg, on the side surface 21c of the magnet 21) about the rotation axis AX. Further, the reference numeral Lx is a tangent line at the position Px of the circumference about the rotation axis AX. In the following description, the direction parallel to the tangent line Lx is referred to as the tangent line direction D1.

The magnetic body 35 has a shape having a longitudinal direction and a lateral direction, and is arranged so as to face the longitudinal direction in the tangential direction D1 (Y direction). For example, the magnetic body 35 (see FIG. 2B) is a columnar member whose axial direction (longitudinal direction) is substantially parallel to the tangential direction D1. The magnetic body 35 has, for example, a shape extending substantially linearly in parallel with the tangential direction D1. Then, an AC magnetic field is applied to the magnetic body 35 in the axial direction (Y direction), and when the direction of the AC magnetic field is reversed, a magnetic domain wall is generated from one end to the other end in the axial direction. As described above, the magnetic body 35 has a property that the internal magnetic domain wall constituting the magnetic domain moves at one time when magnetized (including remagnetization), and the easy magnetization direction is the longitudinal direction (stretching direction, tangential direction). D1). Therefore, for example, in the signal generation unit 31, as a large bulkhausen effect, the magnetic body 35 is magnetized based on the rotation of the magnet 21, and the timing at which the magnetization direction changes (eg, the reversal of the magnetization direction (change in the magnetic field) occurs. Timing) includes a sensor that outputs a pulse signal (detection signal) from the coil unit 36.

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

In the present embodiment, since the signal generation unit 31 is arranged in the radial direction with respect to the magnet 21, for example, the central portion 35a of the magnetic body 35 and the magnet 21 can be arranged close to each other. Further, when the signal generation unit 31 is arranged in the radial direction with respect to the magnet 21 and the sensors (eg, the detection unit 12 and the magnetic detection unit 22 in FIG. 1) are arranged in the axial direction with respect to the magnet 21, the signal is generated. It becomes easy to independently 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. Further, as shown in FIG. 2, for example, the signal generation unit 31 is located outside the magnet 21c at a position where it does not overlap with the magnet 21 in the axial view of the rotation axis AX of the rotating body (or the rotation axis direction view of the magnet 21). It is arranged at a position facing the side surface 21c of the.

The two end portions 35a of the magnetic body 35 in the easy magnetization direction are arranged at positions farther from the magnet 21 than the central portion 35b 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 21c of the magnet 21. The side surface 21c of the magnet 21 is curved so as to move away from the magnetic body 35 from the central portion 35b of the magnetic body 35 toward the end portion 35a. The side surface 21c is curved so as to be convex with respect to the magnetic body 35. Therefore, the signal generation unit 31 is arranged with respect to the magnet 21 (for example, the position where the magnet 21 is arranged) via the gap based on the distance DXa and the distance DXb.

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 the present embodiment has the 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 the magnet becomes relatively weak. In the encoder device EC in 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, the cancellation of the magnetic field at the end portion 35a) is reduced, so that, for example, The large Barkhausen effect is stably generated in the magnetic material 35, and the detection signal is stably generated in the signal generation unit 31 (also described in FIG. 3).

The coil portion 36 is arranged around the magnetic body 35 (eg, near, around, etc.), and a detection signal is generated by electromagnetic induction accompanying the large Barkhausen effect generated in the magnetic body 35. The coil portion 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 generation of the magnetic domain wall in the magnetic body 35, and an induced current flows through the coil portion 36. The detection signal generated by the signal generation unit 31 includes one or both of the induced electromotive force and the induced current of electromagnetic induction generated in the coil unit 36. The above-mentioned detection signal includes, for example, a waveform in which the electric 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 of the magnetic body 35 are all (at once) inverted based on the rotation of the rotating body, the coil unit 36 detects the magnetic field change at the inverted timing and outputs the detection signal. Therefore, the coil unit 36 can output the above-mentioned detection signal including the detection pulse such as a positive pulse and a negative pulse by utilizing the large Barkhausen effect, for example. The direction of the current generated in the coil portion 36 changes depending on the direction before and after the reversal of the magnetic field. The electric power (induced current) generated in the coil portion 36 can be set, for example, by the number of turns of the high-density coil. The detection signal generated in the coil portion 36 can be taken out to the outside via the terminals 37a and 37b. As described above, the coil unit 36 can operate without power supply from the outside (eg, the power supply PW in FIG. 1).

The signal generation unit 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 by 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 generation unit 31 is arranged so that the relative angular position with respect to the magnet 21 changes due to the rotation of the rotating body SF.

For example, when the relative position between the signal generation unit 31 and the magnet 21 becomes a predetermined position (or a specific position), the signal generation unit 31 generates a pulse-shaped 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) for detecting that the relative position with the magnet 21 has reached a predetermined position. In this case, for example, the encoder device EC includes a plurality of signal generation units 31 arranged at different positions (eg, angular positions such as 45 °, 90 °, 180 °, etc., about the rotation axis of the magnet 21). The above-mentioned angular position information and multi-rotation information are calculated by the processing unit (eg, processing units 13 and 23) using the pulsed detection signals output from the plurality of signal generation units 31 based on the rotation of the magnet 21. Can be done.

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

FIG. 3 is a diagram showing a magnetic field formed by the magnet according to the first embodiment. In FIG. 3, the “angle position” is the angle position of the magnet 21 with respect to the state of FIG. 2 (A) as a reference (0 °). Here, the counterclockwise angular position is positive. The magnetic field formed by the magnet 21 at each angle position in FIG. 3 is represented by an arrow (vector). The direction of this arrow indicates 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 of "angle position" from 0 ° to 45 °. Further, on the right side of FIG. 3, the magnetic field is shown in the range of "angle position" of 45 ° to 90 °.

When the "angle position" is 0 °, the magnetic field line at the position of the central portion 35b (see FIG. 2) of the magnetic body 35 faces the −Y side. As the "angle position" goes from 0 ° to 45 °, the strength of the magnetic field lines at the position of the magnetic body 35 decreases. When the "angle position" is 45 °, the strength of the magnetic field at the central portion 35b of the magnetic body 35 becomes almost 0. As the "angle position" goes from 45 ° to 90 °, the strength of the magnetic field lines at the position of the magnetic body 35 increases. When the "angle position" is 90 °, the magnetic field line at the position of the central portion 35b (see FIG. 2) of the magnetic body 35 faces the + Y side. By reversing the direction of the magnetic field lines felt by the magnetic body 35 in this way, a large Barkhausen effect is generated in the magnetic body 35, and a detection signal is generated in the coil portion 36.

In the present embodiment, since the signal generation unit 31 is arranged in the radial direction with respect to the magnet 21, for example, the central portion 35a of the magnetic body 35 and the magnet 21 can be arranged 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 generation unit 31 can stably generate the detection signal.

The direction of the magnetic field lines when the "angle position" is 45 ° is reversed between the + Y side end portion and the −Y side end portion of the magnetic body 35. If the directions of the magnetic field lines are reversed in each portion of the magnetic body 35, the generation of the large Barkhausen effect may not be stable. However, in the present embodiment, the end portion 35a of the magnetic body 35 is arranged at a position farther from the magnet 21 than the central portion 35b of the magnetic body 35. In this case, as 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, and the large bulk housen The occurrence of 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 that contributes to the generation of the large Barkhausen effect can be applied to the central portion 36b more than the central portion 35a.

Further, 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 larger than the magnetic field acting on the end portion 35a when the magnetic body 35 is curved along the magnet 21. Also weakens. Therefore, it is possible to reduce the influence when the directions of the magnetic fields are opposite between the end portion 35a on the + Y side and the end portion 35a on the −Y side. Therefore, the signal generation unit 31 stably generates the large Barkhausen effect and stably generates the detection signal.

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 21a and the S pole 21b adjacent to each other on the inner peripheral side and the outer peripheral side thereof. This magnetic field contains components 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 north pole 21a and the south pole 21b of the magnet 21 at the timing when the detection signal is generated in the signal generation unit 31. For example, the signal generation unit 31 generates a detection signal when the magnet 21 is arranged at a predetermined angle position. The magnetic sensor 25 and the magnetic sensor 26 are respectively arranged at an angle position away from the boundary between the N pole 21a and the S pole 21b in the rotation direction when the magnet 21 is arranged at a predetermined angle position. The magnetic sensor 26 is arranged at an angle position about the rotation axis AX of the magnet 21, for example, in a range of 90 ° or more and less than 180 ° with respect to the magnetic sensor 25.

Returning to the description of FIG. 1, the switching unit 32 uses the detection signal generated by the signal generation unit 31 as a control signal to switch whether or not power is supplied from the battery 33 to the position detection unit 1. The position detection unit 1 receives power from the power supply unit 2 and starts detecting position information. The position detection unit 1 detects the rotation position information of the rotating body SF by the electric 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 generation unit 31 is used for the operation of at least a part of the position detection unit 1 (eg, the multi-rotation information detection unit 1A). For example, the power supply unit 2 supplies the power used for the operation of the position detection unit 1 by using the detection signal generated by the signal generation unit 31 in the backup state. For example, the position detection unit 1 (eg, the multi-rotation information detection unit 1A) performs a 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. conduct.

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 button type battery, a primary battery such as a dry battery, and a secondary battery such as a lithium ion secondary battery.

The switching unit 32 starts supplying electric 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 equal to or higher than the threshold value. For example, the switching unit 32 starts supplying electric power from the battery 33 to the position detection unit 1 when the signal generation unit 31 generates a detection signal equal to or larger than the threshold value.

Further, the switching unit 32 stops the supply of electric 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 supply PW is cut off (backup state), the level (potential) of the detection signal in the switching unit 32 is low. When the power rises to a high level from, the power supply from the battery 33 to the position detection unit 1 is started, and after a predetermined time has elapsed from the change of the level (potential) of this detection signal to the low level, the battery 33 starts to supply power. The power supply to the position detection unit 1 is stopped.

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

The rectifier stack 61 is a rectifier that rectifies the current flowing from the signal generation unit 31. The first input terminal 61a of the rectifying stack 61 is connected to the terminal 37a of the signal generation unit 31. The second input terminal 61b of the rectifying stack 61 is connected to the terminal 37b of the signal generation unit 31. The ground terminal 61g of the rectifying stack 61 is connected to the ground wire 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 wire GL becomes the reference potential of the circuit 60. The output terminal 61c of the rectifying stack 61 is connected to the control terminal 63c 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 (eg, a switching element 64) provided in the power supply path between the battery 33 and the position detection unit 1. The regulator 63 controls the operation of the switching element 64 by using the detection signal generated by the signal generation unit 31 as a control signal (eg, enable signal).

The input terminal 63a 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 wire 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 equal to or higher than the threshold value is applied to the control terminal 63c. The output voltage of the regulator 63 (the above-mentioned predetermined voltage) is, for example, 3V when the counting unit 67 is configured by CMOS or the like. The operating voltage of the storage unit 24 is set to, for example, the same voltage as a predetermined voltage. The predetermined voltage is a voltage required for power supply, and may be a constant voltage value or a voltage that changes stepwise.

The switching element 64 switches between continuity and interruption of the circuit 60 that supplies electric power to the position detection unit 1. The circuit 60 constitutes, for example, a power supply path connecting a first electrode (positive electrode) and a second electrode (negative electrode) of a second power source (eg, battery 33), and includes a power supply line PL and a ground line GL. The ground wire GL is connected to, for example, the negative electrode of the battery 33, and its potential becomes the reference potential of the circuit 60. The switching element 64 switches, for example, 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 generation unit 31 to the control terminal 63c as a control signal (enable signal), and is in a conduction state (on) between the first terminal 64a and the second terminal 64b of the switching element 64. Switch between the isolated state (state) and the isolated state (off state). For example, the switching element 64 includes a MOS, a TFT, and the like, 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 generation unit 31. For example, the switching element 64 cuts off the circuit 60 in a state where the potential of the control terminal 64c is the reference potential of the circuit 60. Further, in the switching element 64, when the voltage of the control terminal 64c becomes a predetermined value or more, the connection between the first terminal 64a and the second terminal 64b becomes a conduction state (on state). The circuit 60 is switched to continuity. When the space between the first terminal 64a and the second terminal 64b is 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 for acquiring 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 shown in FIG. The magnetic sensor 25 and the magnetic sensor 26 are sensors for detecting the rotating body SF, respectively. The magnetic sensor 25 and the magnetic sensor 26 detect the rotating body SF by detecting the magnetic field formed by the magnet 21 attached to the rotating body SF. The magnetic sensor 25 and the magnetic sensor 26 each detect the magnetic field formed by the magnet 21 by using the electric 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 wire GL. The output terminal 25c of the magnetic sensor 25 is connected to the input terminal 65a 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, for example, a comparator, 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 wire GL. The output terminal 65b of the analog comparator 65 is connected to the first input terminal 67a 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 wire GL. The output terminal 26c of the magnetic sensor 26 is connected to the input terminal 66a 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 wire GL. The output terminal 66b of the analog comparator 66 is connected to the second input terminal 67b 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 by using the electric power supplied from the battery 33. The counting unit 67 includes, for example, a CMOS logic circuit. The counting unit 67 operates using the 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 wire GL. The counting unit 67 performs counting processing 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 of the rotation position information (eg, multi-rotation information) detected by the processing unit 23 using the electric power supplied from the battery 33 (performs a writing operation). The storage unit 24 stores the result of counting by the counting unit 67 (multi-rotation information) as the rotation 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 wire GL. The storage unit 24 includes, for example, a non-volatile memory, and can hold information written while power is being supplied even in a state where power is not supplied. The multi-rotation information detection unit 1A may include means for acquiring the on state and the off state of the regulator 63.

In this embodiment, a capacitor 69 is provided between the rectifying stack 61 and the regulator 63. The first electrode 69a of the capacitor 69 is connected to a signal line connecting the rectifying stack 61 and the control terminal 63c of the regulator 63. The second electrode 69b of the capacitor 69 is connected to the ground wire GL. The capacitor 69 is, for example, a smoothing capacitor, which reduces pulsation and reduces the load on the regulator. The constant of the capacitor 69 is, for example, the power supply from the battery 33 to the processing unit 23 and the storage unit 24 is maintained during the period from the detection of the rotation position information by the processing unit 23 to the writing of the rotation position information to 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 the detection and writing of the multi-rotation information is completed, 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 generation unit 31 even in a state where the power supply from the outside is cut off. The multi-rotation information stored in the storage unit 24 is read out to the control unit MC the next time the drive device MTR is started, and is used for calculating the initial position of the rotating body SF and the like.

In the encoder device EC as described above, the magnet 21 is magnetized in the direction intersecting 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 generation unit 31 is arranged in a direction orthogonal to the rotation axis AX of the magnet 21. Therefore, the signal generation unit 31 is arranged so as to be close to the magnet 21, for example, to stably generate a detection signal. Further, as shown in FIG. 2, when the end portion 35a of the magnetic body 35 is arranged at a position farther from the magnet 21 than the central portion 35b, the signal generation portion 31 is, for example, a magnetic field acting on the end portion 35a. By reducing the strength, a detection signal is stably generated.

In addition, one or both of the incremental pattern INC and the absolute pattern ABS may be provided on the surface opposite to the magnet 21 in the scale S (later shown 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 (later shown in FIG. 8B). Further, the magnet 21 may be provided on a first rotating body (eg, scale S) in which one or both of the incremental pattern INC and the absolute pattern ABS are provided, and another second rotating body (later, FIG. 8). (B), shown in FIG. 8 (C)).

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

The signal generation unit 31 may be a detection unit that detects that the relative position with respect to the magnet 21 has reached a predetermined position. In this case, the position detection unit 1 may detect the rotation position information by using the detection result (detection signal) of the signal generation unit 31. For example, the position detection unit 1 may detect the rotation position information by 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 rotation position information by using the detection result of the magnetic detection unit 22 and the detection result (detection signal) of the signal generation unit 31.

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

In the present embodiment, the rotating body SF rotates with respect to the fixing member BD1. The fixing member BD1 includes, for example, a stator in the drive 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) provided with a processing circuit for processing the detection result of the detection unit (magnetic detection unit 22, detection unit 12, signal generation unit 31). 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 synthesis unit 27, and the switching unit 32 shown in FIG.

The second support member 42 is arranged between the fixing 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, a spacer, or the like. The second support member 42 may be made of, for example, a resin, or at least a metal having an insulating surface (eg, made of alumite-processed aluminum).

The second support member 42 defines a gap between the detection unit (magnetic detection unit 22, detection unit 12) and the rotating body SF between the fixing 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. Further, 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 encloses the scale S (or the magnet 21) in an annular shape. The second support member 42 has, for example, a ring shape in a rotation axis view. The first support member 41 is provided so as to close the side opposite to the fixing member BD1 in the second support member 42. 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 drive device MTR through the through hole 44 provided in the second support member 42. The second support member 42 is sandwiched (co-tightened) between the first support member 41 and the fixing member BD1 and fixed to each of the first support member 41 and the fixing member BD1. In this way, 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 housed in the space SP1 surrounded by the fixing member BD1, the first support member 41, and the second support member 42. Further, the second support member 42 is arranged 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 housed in the space SP1. Here, as shown in FIG. 5, in the second support member 42 in the present embodiment, at least a part of the signal generation unit 31 is provided with an inner circumference 42a (inner edge) and an outer circumference 42b (outer edge) of the second support member 42. Contain in between. For example, the second support member 42 has an internal space SP2 (see FIGS. 5A and 5B) between the inner peripheral 42a and the outer peripheral 42b, and the signal generation unit 31 is housed in the internal space SP2.

In this way, the second support member 42 seals and fixes the signal generation unit 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 hollow shape, a concave portion, a groove, or a hole. Further, for example, the internal space SP2 may be formed of one member of the second support member 42, or may be formed of 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 accommodating the signal generation unit 31 inside. In this case, the signal generation unit 31 is embedded in the internal space SP2 of the second support member 42.

In FIG. 5B, at least a part of the magnetic body 35 is arranged 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 arranged on the side (−Z side) closer to the fixing member BD1 of the drive device MTR than the magnet 21. Further, the magnetic body 35 may be arranged on a side (+ Z side) farther from the fixing member BD1 of the drive device MTR than the magnet 21.

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

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

As described above, the signal generation unit 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 generation unit 31 is housed and fixed inside at least a part of the second support member 42 (eg, an internal space). Therefore, the encoder device EC can support the signal generation unit 31 by utilizing, for example, the space between the fixing member BD1 and the first support member 41, and the space can be saved. 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 does not have to be cylindrical, and for example, the shape in the rotation axis view may be a polygonal frame shape (eg, a square frame shape). The second support member 42 does not have to seal at least a part (eg, magnetic body 35, coil portion 36) of the signal generation portion 31. For example, the internal space SP2 of the second support member 42 may be connected to the space SP1. At least a part of the signal generation unit 31 (eg, the magnetic body 35, the coil unit 36) may be exposed to the space SP1.

It should be noted that one or both of the terminal 37a and the terminal 37b of the signal generation unit 31 may not be arranged on the surface 41a of the first support member 41. For example, the terminal of the first support member 41 is arranged on the surface 41b, and one or both of the terminal 37a and the terminal 37b of the signal generation unit 31 are electrically connected to the terminal of the first support member 41 on the surface 41b. May be good. Further, 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 other than soldering (eg, contact).

Next, a modified example according to the embodiment will be described. FIG. 6 is a diagram showing a magnet according to an 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 portion 52 between the magnetizing portions 51 adjacent to each other in the rotation direction of the rotation axis AX is a neutral portion having weaker magnetism than the magnetizing portion 51. The magnet 21 having such an intermediate portion 52 can reduce the strength of the magnetic field acting on both ends of the magnetic body 35 at different angular positions of the magnetic fields at both ends 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 material 35, and the detection signal is stably generated in the signal generation unit 31.

The magnet 21 in FIG. 6A includes, for example, a magnet with radial anisotropic magnetism. In the magnet 21, the N pole 21a and the S pole 21b are aligned in the rotation direction of the rotation axis AX in the magnetizing portion 51. Further, in the magnet 21, the N pole 21a and the S pole 21b are arranged in the radial direction in the magnetizing portion 51. The magnet 21 in FIG. 6B includes, for example, a magnet for polar anisotropic magnetization. In the magnet 21 according to the embodiment, the strength of the magnetic field in the axial direction may be weaker than the strength of the magnetic field in the rotational 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 in the same manner as the signal generation unit 31.

FIG. 7 is a diagram showing a modified example 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 portion 52 is, for example, a non-magnetic material or a member having a lower magnetic permeability than the magnetized portion 51. The magnet 21 is formed, for example, by fixing (eg, integrating) the magnetized portion 51 and the intermediate portion 52. The magnet 21 may be formed by fixing the base material, which is the magnetizing portion 51 before magnetization, and the intermediate portion 52, and then magnetizing the base material.

The 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 (eg, 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 portion 52 of the magnetizing portions 51 adjacent to each other in the rotation direction is, for example, a void (atmospheric gas). Further, the magnetized portions 51 of the magnet 21 shown in FIG. 7C are bar magnets, and are discretely arranged at specific intervals in the rotation direction. In the magnet 21, for example, four pairs of bar magnets are arranged at equal intervals in the rotation direction.

FIG. 8 is a diagram showing an encoder device according to an 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, for example, a surface facing the first support member 41. The detection unit 12 is supported by the first support member 41 and is arranged 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 on the scale S. At least a part of the magnet 21 is arranged at a position where it overlaps with, for example, the incremental pattern INC or the absolute pattern ABS in the axial direction. The magnet 21 may be arranged at a position where it does not overlap with the incremental pattern INC or the absolute pattern ABS in the axial direction.

The magnetic detection unit 22 of the present embodiment is supported by the first support member 41 and another third support member 55. The third support member 55 is fixed to the second support member 42 at one end, for example. The third support member 55 rotatably supports the scale S at the other end, for example, by a bearing 55a. The third support member 55 may be fixed to the fixing member BD1 of the drive device MTR. Further, the third support member 55 does not have to 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 arranged 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 is arranged on the same side (eg, 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 arranged on the same side as the first support member 41 with respect to the scale S. The rotating member 56 is, for example, 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 arranged so as to face the magnet 21.

The signal generation unit 31 may be supported by a member other than the second support member 42. In FIG. 8B, the signal generation unit 31 is supported by the first support member 41. For example, the signal generation unit 31 includes a case 57 that supports the magnetic material 35 and the coil unit 36. The case 57 houses the magnetic body 35 and the coil portion 36, and is fixed to the first support member 41. Further, 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 arranged in a hole 58 (eg, a bottomed depression, 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 generation unit 31 may be supported by a member different from the first support member 41 (eg, the third support member 55). Further, the signal generation unit 31 may be supported by the second support member 42. For example, the second support member 42 may have a protruding portion protruding inward in the radial direction like the third support member 55, and the signal generating portion 31 may be supported by the protruding portion of the second support member 42. .. In this case, the signal generation unit 31 does not have to be housed in the second support member 42.

FIG. 9 is a diagram showing a signal generation unit according to the embodiment. In FIG. 9A, in the signal generation 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 along 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 arranged on the opposite side of the magnetic body 35 from the magnet 21. Further, as shown in FIG. 9B, the encoder device EC may include a plurality of signal generation units 31. The number of signal generation units 31 may be one as shown in FIG. 1, may be two as shown in FIG. 9B, or may be three or more. As described above, the signal generation unit 31 in the present embodiment is the magnet 21 in the first direction (eg, orthogonal radial directions, etc.) intersecting the rotation axis direction of the magnet 21 (in this case, the axial direction of the rotation axis AX). The magnetic field (magnetic field) formed by the magnet 21 arranged to face at least a part of the magnet 21 and magnetized in the first direction is detected.

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

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

In the drive device MTR, the control unit MC shown in FIG. 1 or the like controls the main body unit BD by using the detection result of the encoder device EC. The drive device MTR can operate stably, for example, by stably generating a detection signal in the signal generation unit 31 of the encoder device EC. Further, the drive device MTR can reduce the maintenance cost, for example, by eliminating or reducing the need for battery replacement of the encoder device EC. The drive device MTR is not limited to the 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 in the present embodiment, the encoder device EC has a plurality of (in this case, two) position detection units 1 and a plurality of (in this case, two) electric power. It may be a double encoder type device including a supply unit 2. In this case, for example, one of the two position detection units 1 detects the rotation position information of the rotating body SF, and the other of the two position detection units 1 detects the 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 showing a stage device according to an embodiment. In the following description, the same or equivalent components as those in the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted or simplified.

This stage device STG has a configuration in which a stage (rotary table TB, moving body, rotating body) is attached to the load side end SFa of the rotating body SF of the drive device MTR shown in FIG. The stage device STG may be configured to linearly move the stage in one direction by, for example, a one-dimensional linear motor. Further, the stage device 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, a planar motor).

The stage device STG drives the drive device MTR to rotate the rotating body SF. This rotation is transmitted to the rotary table TB, and at that time, the encoder device EC detects the angular position of the rotating body SF and the like. By using the output from the encoder device EC, the angular position of the rotary table TB can be detected. A speed reducer or the like may be arranged 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, by stably generating a detection signal in the signal generation unit 31 of the encoder device EC. Further, the stage device STG can reduce the maintenance cost, for example, because the need for battery replacement of the encoder device EC is low or not. The stage device STG can be applied to, for example, a rotary table provided in a machine tool such as a lathe.

[Robot device]
Next, the robot device according to the embodiment will be described. FIG. 12 is a diagram showing a robot device according to an embodiment. Note that FIG. 12 schematically shows a part (joint portion) of the robot device RBT. In the following description, the same or equivalent components as those in the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted or simplified. This robot device RBT has 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 connecting portion 102a. The connecting portion 102a is arranged between the bearing 101a and the bearing 101b in the joint portion JT. The connecting portion 102a is provided integrally with the rotating body SF2. The rotating body SF2 is inserted into both the bearing 101a and the bearing 101b at the joint portion JT. The end of the rotating body SF2 on the side inserted into the bearing 101b penetrates the bearing 101b and is connected to the speed reducer RG.

The speed reducer RG is connected to the drive device MTR, and reduces the rotation of the drive device MTR to, for example, 1/100 or the like and transmits the rotation to the rotating body SF2. Of the rotating body SF of the drive device MTR, the load side end SFa is connected to the speed reducer RG. Further, the scale S of the encoder device EC is attached to the counterload side end SFb of the rotating body SF of the drive device MTR.

When the robot device RBT drives the drive device MTR to rotate the rotating body SF, this rotation is transmitted to the rotating body SF2 via the speed reducer RG. The rotation of the rotating body SF2 causes the connection portion 102a to rotate integrally, whereby the second arm AR2 rotates with respect to the first arm AR1. At that time, the encoder device EC detects the angular position of the rotating body SF and the like. Therefore, by using the output from the encoder device EC, the angular position of the second arm AR2 can be detected.

The robot device RBT can operate stably, for example, by stably generating a detection signal in the signal generation unit 31 of the encoder device EC. The robot device RBT can reduce the maintenance cost, for example, by eliminating or reducing the need for battery replacement of the encoder device EC. The robot device RBT is not limited to the above configuration, and the drive device MTR can be applied to various robot devices having joints.

The technical scope of the present invention is not limited to the embodiments described in the above-described embodiments. One or more of the requirements described in the above embodiments and the like may be omitted. Further, the requirements described in the above-described embodiments and the like can be appropriately combined. In addition, to the extent permitted by law, the disclosure of all documents cited in the above-mentioned embodiments and the like shall be incorporated as part of the description in the main text.

1 ... position detection unit (detection unit), 2 ... power supply unit, S ... scale, 13 ... processing unit, 21 ... magnet. 21c ... Side surface, 22 ... Magnetic detection unit (detection unit), 23 ... Processing unit, 24 ... Storage unit, 31 ... Signal generation unit, 35 ... Magnetic material, 35a ... -End part, 35b ... Central part, 36 ... Coil part, 41 ... First support member, 42 ... Second support member, AX ... Rotating shaft, EC ... Encoder device, SF: Rotating body, TB: Rotating table (stage), 101: Arm, BD1: Fixed member, MTR: Drive device, RBT: Robot device, STG: Stage Device

Claims (20)

A detector that detects the rotation position information of the rotating body,
A magnet that rotates relative to the detection unit,
A signal generation unit that is arranged in a direction orthogonal 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 the magnetic field formed by the magnet.
A support member that supports the signal generation unit and accommodates at least a part of the signal generation unit is provided.
The magnet is magnetized in a direction orthogonal to the rotation axis, and the magnet is magnetized .
A first support member that supports at least a part of the detection unit is provided.
The rotating body rotates with respect to the fixing member and
The support member is a second support member arranged between the fixing member and the first support member.
The second support member is an encoder device that defines a gap between the detection unit and the rotating body between the fixing member and the first support member . A detector that detects the rotation position information of the rotating body,
A magnet that rotates relative to the detection unit,
A signal generation unit that is arranged in a direction orthogonal 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 the magnetic field formed by the magnet.
A support member that supports the signal generation unit and accommodates at least a part of the signal generation unit is provided.
The magnet is magnetized in a direction orthogonal to the rotation axis, and the magnet is magnetized.
A first support member that supports at least a part of the detection unit is provided.
The rotating body rotates with respect to the fixing member and
The support member is a second support member arranged between the fixing member and the first support member.
The second support member is an encoder device fixed to each of the first support member and the fixing member . A detector that detects the rotation position information of the rotating body,
A magnet that rotates relative to the detection unit,
A signal generation unit that is arranged in a direction orthogonal 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 the magnetic field formed by the magnet.
A support member that supports the signal generation unit and accommodates at least a part of the signal generation unit is provided.
The magnet is magnetized in a direction orthogonal to the rotation axis, and the magnet is magnetized.
A first support member that supports at least a part of the detection unit is provided.
The rotating body rotates with respect to the fixing member and
The support member is a second support member arranged between the fixing member and the first support member.
The second support member defines a gap between the detection unit and the rotating body between the fixing member and the first support member, and is fixed to each of the first support member and the fixing member . Encoder device. The signal generator is
A magnetic material that produces the large Barkhausen effect due to changes in the magnetic field formed by the magnet,
The encoder device according to any one of claims 1 to 3, further comprising a coil portion for generating the detection signal by the large Barkhausen effect. The encoder device according to claim 4 , wherein the end portion of the magnetic material in the easy magnetization direction is arranged at a position farther from the magnet than the central portion of the magnetic material. The magnet is arranged along the rotation direction of the rotating body, and the magnet is arranged.
The encoder device according to claim 4 or 5 , wherein the magnetic material is arranged so as to extend in a tangential direction on the outer periphery of the rotating body. The encoder device according to any one of claims 1 to 6 , wherein the magnet forms a magnetic field in the rotation direction of the rotation axis. The encoder device according to any one of claims 1 to 7 , wherein the magnet is discretely provided in the rotation direction of the rotating body. The encoder device according to any one of claims 1 to 7 , wherein the magnet has four or more magnetic poles in the rotation direction of the rotating body. The encoder device according to any one of claims 1 to 9 , wherein the magnet includes a magnet of radial anisotropic magnetization or polar anisotropic magnetization. The encoder device according to any one of claims 1 to 10 , wherein the magnet has a side surface that curves along the rotation direction of the rotating body. Including a processing unit that processes the detection result of the detection unit.
The encoder device according to any one of claims 1 to 11, wherein the first support member includes a substrate provided with the processing unit. The encoder according to any one of claims 1 to 12 , wherein the second support member accommodates at least a part of the signal generation unit between the inner circumference and the outer circumference of the second support member. Device. The encoder device according to any one of claims 1 to 13 , wherein the second support member is arranged so as to cover at least a part of the detection unit. The encoder device according to any one of claims 1 to 14 , wherein the second support member is annularly surrounded by the magnet. The encoder device according to any one of claims 1 to 15 , 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 device according to any one of claims 1 to 16 , further comprising a power supply unit that supplies electric power to the detection unit based on the detection signal. The encoder device according to any one of claims 1 to 17 , and the encoder device.
A drive device including a drive unit that supplies a drive force to the rotating body. The drive device according to claim 18 ,
A stage device including a stage moved by the drive device. The drive device according to claim 18 ,
A robot device including an arm moved by the drive device.

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