WO2014049743A1 - Codeur, procédé de fabrication de codeur et servo-système - Google Patents

Codeur, procédé de fabrication de codeur et servo-système Download PDF

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Publication number
WO2014049743A1
WO2014049743A1 PCT/JP2012/074770 JP2012074770W WO2014049743A1 WO 2014049743 A1 WO2014049743 A1 WO 2014049743A1 JP 2012074770 W JP2012074770 W JP 2012074770W WO 2014049743 A1 WO2014049743 A1 WO 2014049743A1
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WO
WIPO (PCT)
Prior art keywords
magnet
disk
encoder
rotating body
magnetic field
Prior art date
Application number
PCT/JP2012/074770
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English (en)
Japanese (ja)
Inventor
宏樹 近藤
正信 原田
Original Assignee
株式会社安川電機
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by 株式会社安川電機 filed Critical 株式会社安川電機
Priority to CN201280075798.5A priority Critical patent/CN104620081A/zh
Priority to PCT/JP2012/074770 priority patent/WO2014049743A1/fr
Publication of WO2014049743A1 publication Critical patent/WO2014049743A1/fr

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
    • G01D5/244—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing characteristics of pulses or pulse trains; generating pulses or pulse trains
    • G01D5/24428—Error prevention
    • G01D5/24433—Error prevention by mechanical means
    • G01D5/24442—Error prevention by mechanical means by mounting means

Definitions

  • the disclosed embodiment relates to an encoder, an encoder manufacturing method, and a servo system.
  • Patent Document 1 describes an encoder that detects a multi-rotation amount by detecting a magnetic field of a magnet fixed to a rotating disk.
  • magnets have the property of demagnetizing at high temperatures. For this reason, in the above-described conventional encoder, the magnet is demagnetized due to heat generation of a detection target such as a motor or an increase in the outside air temperature, so that a sufficient magnetic flux for multi-rotation detection cannot be obtained, and detection accuracy may be lowered. There was sex.
  • an object of the present invention is to provide an encoder capable of suppressing a decrease in detection accuracy due to demagnetization of a magnet, and an encoder manufacturing method To provide a servo system.
  • a rotating body A magnet held by the rotating body; A magnetism detection unit that is arranged opposite to the rotating body of the magnet and that detects magnetism generated by the magnet, The magnet There is provided an encoder configured such that the magnetic flux density on the surface on the magnetic detection unit side is larger than the magnetic flux density on the surface on the rotating body side.
  • a rotating body a magnet held by the rotating body, and the magnet is disposed opposite to the rotating body,
  • a magnetic detection unit for detecting magnetism generated by the magnet, and an encoder manufacturing method comprising: Magnetizing a magnet material between a magnetized yoke and a back yoke by a magnetizing device to produce the magnet; Fixing the magnet to the rotating body by a fixing device so that the surface on the magnetizing yoke side is on the magnetic detecting unit side and the surface on the back yoke side is on the rotating body side.
  • a manufacturing method is provided.
  • a rotatable glass disk A magnet fixed to the surface of one side of the disk; A hub fixed to the surface of the other side of the disk and connected to a detection target; A magnetism detection unit disposed opposite to the magnet and detecting magnetism generated by the magnet, The magnetic detection unit is An encoder is provided that is fixed to the rotating disk, the magnet, and the hub without bearings.
  • a motor including an encoder that rotates a shaft and detects the position of the shaft; A motor control device that performs drive control of the motor based on the detection result of the encoder,
  • the encoder is A rotating body, A magnet held by the rotating body;
  • a magnetism detection unit that is arranged opposite to the rotating body of the magnet and that detects magnetism generated by the magnet, The magnet
  • a servo system configured such that the magnetic flux density on the surface on the magnetic detection unit side is larger than the magnetic flux density on the surface on the rotating body side.
  • FIG. 1 is an explanatory diagram for explaining an example of a configuration of a servo system according to the present embodiment.
  • the servo system S includes a servo motor SM (an example of a motor) and a control device CT (an example of a motor control device).
  • the servo motor SM includes an encoder 100 and a motor M.
  • the motor M is an example of a power generation source that does not include the encoder 100. Although the motor M alone may be referred to as a servo motor, in this embodiment, a configuration including the encoder 100 is referred to as a servo motor SM.
  • the motor M has a shaft SH (an example of a detection target), and outputs a rotational force by rotating the shaft SH around the rotation axis AX.
  • the motor M is not particularly limited as long as it is a motor controlled based on data representing the detection result of the encoder 100 such as position data.
  • the motor M is not limited to an electric motor that uses electricity as a power source.
  • a motor using another power source such as a hydraulic motor, an air motor, or a steam motor. It may be.
  • a case where the motor M is an electric motor will be described below.
  • the encoder 100 is connected to a shaft SH on the side opposite to the torque output side (also referred to as load side) of the motor M (also referred to as anti-load side).
  • the arrangement position of the encoder 100 is not particularly limited, and the encoder 100 may be connected to the shaft SH or the like via another mechanism such as a speed reducer, a rotation direction changer, or a brake.
  • the encoder 100 detects the position (angle) of the shaft SH, thereby detecting the position x (also referred to as a rotation angle) of the motor M, and outputs position data representing the position x.
  • the encoder 100 includes at least the speed of the motor M (also referred to as rotational speed, angular velocity, etc.) and the acceleration of the motor M (also referred to as rotational acceleration, angular acceleration, etc.).
  • the speed and acceleration of the motor M can be detected by, for example, processing such as differentiating the position x by the first or second order with respect to time or counting the detection signal for a predetermined time.
  • processing such as differentiating the position x by the first or second order with respect to time or counting the detection signal for a predetermined time.
  • the following description will be made assuming that the physical quantity detected by the encoder 100 is the position x.
  • the control device CT acquires the position data output from the encoder 100 and controls the rotation of the motor M based on the position data. Therefore, in this embodiment in which an electric motor is used as the motor M, the control device CT controls the rotation of the motor M by controlling the current or voltage applied to the motor M based on the position data. . Further, the control device CT acquires a high-order control signal from a high-order control device (not shown), and a rotational force capable of realizing the position or the like represented by the high-order control signal is output from the shaft SH. It is also possible to control the motor M. When the motor M uses another power source such as a hydraulic type, an air type, or a steam type, the control device CT controls the rotation of the motor M by controlling the supply of these power sources. Is possible.
  • FIGS. 2 to 5 are explanatory diagrams for explaining an example of the configuration of the encoder according to the present embodiment.
  • FIG. 2 is a cross-sectional view illustrating an example of the configuration of the encoder according to the present embodiment.
  • FIG. 3 is a partially enlarged view of part A in FIG.
  • FIG. 4 is a plan view illustrating an example of the configuration of the rotating body, the detection target, the optical module, and the magnetic detection unit according to the present embodiment.
  • FIG. 5 is a plan view illustrating an example of the configuration of the detection target and the magnetic detection unit according to the present embodiment.
  • the following directions such as up and down are defined as follows. That is, the Z-axis positive direction that is the anti-load side direction in the rotation axis AX is expressed as “up” or “upward”, and the negative Z-axis direction that is the opposite load side direction is “down” or “down”.
  • the positional relationship between the components of the encoder 100 according to the present embodiment is not particularly limited to concepts such as up and down.
  • other directions may be used for the directions determined here, or directions other than these may be used while being described as appropriate.
  • the encoder 100 As shown in FIG. 2, the encoder 100 according to the present embodiment is provided in the housing 10 of the motor M and is covered with an encoder cover 101.
  • the encoder 100 includes a substrate 16, a support member 150, a rotating body R, a detection target 170, a magnetic detection unit 120, an optical module 130, and a position data generation unit 140.
  • the substrate 16 is a disc-shaped printed wiring board, and a plurality of circuit elements and the like are mounted on the lower surface thereof.
  • the substrate 16 is formed to have substantially the same diameter as the support member 150, and an edge portion of the substrate 16 is placed on the surface 151 of the support member 150.
  • a plurality of through holes 16 ⁇ / b> A through which the fixing screws 15 pass are provided at the edge of the substrate 16 at substantially equal intervals in the circumferential direction.
  • the support member 150 is formed in a cylindrical shape and supports the substrate 16.
  • the support member 150 has a plurality of through holes 152 through which the fixing screw 15 passes.
  • the fixing screw 15 passes through the through hole 16 ⁇ / b> A of the substrate 16 and the through hole 152 of the support member 150 in the vertical direction, and is screwed into a screw hole provided in the housing 10. As a result, the substrate 16 and the support member 150 are fixed to the housing 10.
  • the rotator R has a hub 160 and a disk 110 (an example of a magnet fixing portion).
  • the hub 160 is made of a metal such as stainless steel (also called SUS (Steel Use Stainless)).
  • the material (material) of the hub 160 is not limited to metal.
  • the hub 160 has a disk fixing portion 162 and a bolt fastening portion 163.
  • the disk fixing portion 162 is formed in an annular shape, and on the surface 162A (hereinafter also referred to as the upper surface 162A), the surface 110B (the other surface, also referred to as the lower surface 110B below) of the disk 110 is vertically located. It is abutted in the direction and bonded and fixed (fixed) with an appropriate adhesive.
  • the bolt fastening portion 163 is formed in a convex shape protruding upward at a substantially central portion (inner side) of the disc fixing portion 162, and the disc 110 and the hub 160, which will be described later, are arranged so as to have the same axial center. It fits into the through hole 111.
  • a through-hole 161 through which the bolt 14 passes is provided in a substantially central portion (inner side) of the bolt fastening portion 163.
  • the bolt 14 passes through a through-hole 171 of the detection object 170 described later, a through-hole 111 of the disk 110 described later, and a through-hole 161 in the vertical direction, and is screwed into a bolt hole 13 provided in the shaft SH.
  • the seat surface 14A of the bolt 14 is in contact with the surface 163A (hereinafter also referred to as the upper surface 163A) of the bolt fastening portion 163.
  • the hub 160 is directly fixed to the upper end portion of the shaft SH, and the disk 110 fixed to the disk fixing portion 162 of the hub 160 is connected to the shaft SH.
  • the encoder 100 is a so-called “built-in type” encoder in which the disk 110 is directly connected to the shaft SH via the hub 160.
  • a stepped portion 164 is formed between the disk fixing portion 162 and the bolt fastening portion 163 due to the height difference between the upper surfaces 162A and 163A in the vertical direction.
  • the stepped portion 164 functions as a stopper that abuts against the inner peripheral surface 110 ⁇ / b> C of the disk 110 and regulates the movement of the disk 110 when adjusting the position for centering the disk 110 and the hub 160.
  • the stepped portion 164 has a height dimension L1 (vertical dimension) such that the head portion 14B of the bolt 14 does not interfere with each element such as a magnetoresistive element 121 and a magnetic field detecting element 122 of the magnetic detecting section 120 described later.
  • the height dimension L1 of the stepped portion 164 is substantially half of the thickness dimension (vertical dimension) L2 of the disk 110.
  • the disk 110 is formed in a disk shape centered on the disk center O, and a through hole 111 through which the bolt 14 penetrates and the bolt fastening part 163 is fitted is provided at a substantially central part (inner side). It has been. As described above, the lower surface 110B of the disk 110 is fixed to the upper surface 162A of the disk fixing portion 162 in a state where the bolt fastening portion 163 is fitted in the through-hole 111, and is aligned with the shaft SH. , Connected to the shaft SH. Accordingly, the disk 110 is rotated by the rotation of the motor M, that is, the rotation of the shaft SH. In the present embodiment, the disk 110 is described as an example of the measurement target for measuring the rotation of the motor M, but other members such as an end surface of the shaft SH can also be used as the measurement target. .
  • a slit array SA is formed on the surface 110A of the disk 110 (the surface on one side, hereinafter also referred to as the upper surface 110A).
  • the slit array SA is formed as a track arranged in an annular shape around the disc center O on the upper surface 110 ⁇ / b> A of the disc 110.
  • the slit array SA has a plurality of reflective slits (an example of a slit, not shown) arranged along the circumferential direction over the entire circumference of the track. Each reflection slit reflects light emitted from a light source 131 of the optical module 130 described later.
  • the encoder 100 is a so-called “reflective” encoder in which light from the light source 131 is reflected by a reflection slit and received by a light receiving element described later.
  • the plurality of reflection slits are arranged on the entire circumference of the disk 110 so as to have an absolute pattern in the circumferential direction.
  • the absolute pattern is a pattern in which the position and ratio of reflection slits within an angle at which a light receiving array of the optical module 130 (to be described later) faces are uniquely determined within one rotation of the disk 110. That is, when the motor M is at a certain position x, a combination (detection on / off bit pattern by detection) of each of a plurality of light receiving elements of a light receiving array, which will be described later, facing each other is the position x. Absolute values (absolute position, absolute position) are uniquely expressed.
  • the absolute pattern generation method can use various algorithms as long as the absolute position of the motor M can be generated in a one-dimensional manner by using the number of light receiving elements of the light receiving array described later. It is.
  • the disk 110 is made of glass.
  • Glass has a lower thermal conductivity than metal (for example, stainless steel). Therefore, when the disk 110 is made of glass, it is possible to suppress the heat generated by the shaft SH of the motor M from being transmitted from the hub 160 to the detected object 170 fixed to the disk 110.
  • the reflective slit of the slit array can be formed by applying a light reflecting member to the upper surface 110A of the glass disk 110.
  • the method of forming the reflective slit is not limited to this example.
  • a surface 170B (hereinafter also referred to as a lower surface 170B) of the detection object 170 is vertically contacted and fixed (fixed) to the upper surface 110A of the disk 110 by an appropriate adhesive.
  • the rotating body R has a groove 190.
  • the groove 190 is formed along the circumferential direction so as to be recessed downward from the upper surface 110 ⁇ / b> A of the disk 110 at the inner peripheral side end of the disk 110.
  • the groove 190 is formed by a gap between the stepped portion 164 and the inner peripheral surface 110 ⁇ / b> C of the disk 110.
  • the groove 190 is used as an adjustment allowance for position adjustment for centering the disk 110 and the hub 160.
  • the groove 190 can also be used as a reservoir groove for an adhesive used for bonding the detected object 170 and the disk 110.
  • the detected object 170 is brought into contact with the disk 110 in the vertical direction and bonded and fixed with an appropriate adhesive.
  • the adhesive used for these adhesions may protrude.
  • the adhesive that bonds the disk 110 and the detection object 170 is not particularly limited, and for example, an anaerobic adhesive can be used. Anaerobic adhesive is liquid when in contact with air, but hardens and adheres by blocking air. Therefore, when an anaerobic adhesive is used as an adhesive for bonding the disk 110 and the detected object 170, the adhesive is likely to protrude from the gap between the detected object 170 and the disk 110.
  • the protruding adhesive is indicated by the symbol AD.
  • the inner peripheral surface 170C of the detection object 170 protrudes inward from the inner peripheral surface 110C of the disk 110, and a part of the protruding adhesive AD is subjected to surface tension. By the action, it can be guided to flow downward along the inner peripheral surface 110C of the disk 110.
  • the groove 190 is formed at the inner circumferential end of the disk 110, and the adhesive AD that has flowed downward along the inner circumferential surface 110C of the disk 110, It is possible to flow into the groove 190 and store it.
  • the detected object 170 is held by the disk 110 by fixing the lower surface 170B to the upper surface 110A of the disk 110 so as to be coaxial with the disk 110. It rotates with the disk 110.
  • the detection object 170 is formed in an annular shape and is provided over the entire rotation angle range of 360 degrees.
  • a through-hole 171 through which the bolt 14 passes is provided in a substantially central portion (inner side) of the detection object 170.
  • the detected body 170 has a height dimension (vertical dimension) such that a magnetoresistive element 121 and a magnetic field detection element 122 of the magnetic detection unit 120, which will be described later, fixed to the lower surface of the substrate 16 can accurately detect the magnetic field.
  • a gap G is formed between the outer peripheral surface 170D of the detection object 170 and the surface 130A on the radial inner side of the shaft SH in the optical module 130 fixed to the lower surface of the substrate 16, and the detection object
  • the installation positions of 170 and the optical module 130 do not overlap in the radial direction.
  • the detected object 170 and each element such as a light source 131 and a light receiving element of the optical module 130 described later do not interfere with each other in the vertical direction.
  • the inner diameter L3 of the through hole 111 of the disk 110 is formed larger than the inner diameter L4 of the through hole 171. More specifically, even if the tolerance of the through hole 111 and the tolerance of the through hole 171 are considered, the inner diameter dimension L3 is necessarily larger than the inner diameter dimension L4. For this reason, the inner peripheral surface 170C of the detection object 170 protrudes inward from the inner peripheral surface 110C of the disk 110.
  • the detected object 170 is manufactured by magnetizing a part of an annular magnet material, and has a magnetized portion 172 and a non-magnetized portion 173.
  • the magnetized portion 172 is a magnet material portion that is magnetized and manufactured as a magnet, and generates magnetism (magnetic field).
  • the magnetized portion 172 corresponds to an example of a magnet.
  • the unmagnetized portion 173 is a portion other than the magnetized portion 172, that is, a magnet material portion that has not been magnetized, and does not generate magnetism (magnetic field). Note that the through-hole 171 of the detected object 170 can be said to be a through-hole of the magnetized portion 172 and the non-magnetized portion 173.
  • a rotation angle range of approximately 180 degrees (an example of a predetermined rotation angle) in the detected object 170 is magnetized to become the magnetized portion 172, and the remaining rotation angle range of approximately 180 degrees is not yet adhered.
  • the non-magnetized portion 173 is a portion of the detected object 170 other than the magnetized portion 172, that is, a portion having the same shape as the magnetized portion 172 located on the opposite side in the rotation direction of the magnetized portion 172. .
  • the boundary which is the boundary of the presence or absence of magnetism in the detected object 170 is two substantially contrasting positions B1 and B2 within the rotation angle of 360 degrees.
  • the detected object 170 is arranged so that one of the positions B1 and B2 (position B1 in this example) substantially coincides with the origin position (also referred to as 0 degree position) P for detecting the absolute position of the disk 110. Has been.
  • a magnetic field is generated from the magnetized portion 172 in the rotation angle range of approximately 180 degrees corresponding to the magnetized portion 172, but the remaining approximately 180 degrees of rotation corresponding to the unmagnetized portion 173. No magnetic field is generated in the angular range.
  • FIGS. 6A and 6B are explanatory views for explaining an example of a method for producing a magnetized portion according to the present embodiment.
  • FIG. 6A is a side view of the magnetizing apparatus.
  • 6B is a cross-sectional view corresponding to a VIB-VIB cross section in FIG. 6A.
  • the magnetizing apparatus 200 includes a magnetizing yoke 220 and a back yoke 210 on a circular plate.
  • the magnetizing yoke 220 has a mounting surface 220A on which the detection object 170 is mounted, and a groove 221 is formed on the mounting surface 220A.
  • a magnetizing coil 230 is accommodated in the groove 221.
  • the magnetizing yoke 220 becomes an electromagnet, and the magnetized yoke 220 is wound around the magnetized coil 230, that is, the arc-shaped inner peripheral region 220 ⁇ / b> B and outer peripheral region.
  • a magnetic field (lines of magnetic force) is generated from 220C.
  • the inner peripheral side region 220B is an S pole on the side where the magnetic lines of force enter
  • the outer peripheral side region 220C is on the side where the magnetic lines of force exit. It is comprised so that it may become N pole which is.
  • the magnetized portion 172 can be manufactured by magnetizing the object 170 to be detected between the magnetized yoke 220 and the back yoke 210 with such a magnetizing apparatus 200. That is, the detection object 170 is placed on the mounting surface 220 ⁇ / b> A of the magnetizing yoke 220, the back yoke 210 is overlaid thereon, and a current is passed through the magnetizing coil 230 in the direction of arrow C. Then, the magnetic pole pattern of the magnetized yoke 220 is magnetized so as to be transferred to the detected body 170.
  • the surface on the side of the magnetized yoke 220 that contacts the inner peripheral side region 220B of the magnetized yoke 220 is the N pole because the magnetic pole line is on the side, and the back yoke on the opposite side
  • the surface on the 210 side is the side on which the magnetic pole line enters, so that it becomes the S pole.
  • the surface on the magnetizing yoke 220 side that contacts the outer peripheral side region 220C of the magnetizing yoke 220 becomes the S pole because the magnetic pole line enters, and the back yoke 210 on the opposite side thereof.
  • the magnetized portion 172 is manufactured in the detection object 170.
  • the method for manufacturing the magnetizing device 200 and the magnetized portion 172 described here is an example, and the method for manufacturing the magnetizing device and the magnetized portion 172 is not limited to this example.
  • the magnetic flux density on the surface on the magnetized yoke 220 side is larger than the magnetic flux density on the surface on the back yoke 210 side.
  • the surface on the magnetizing yoke 220 side is the upper side (magnetic detection unit 120 side), and the surface on the back yoke 210 side is the lower side (disk 110 side).
  • the disk 110 is fixed to the upper surface 110A by an appropriate fixing device (not shown). That is, in the detection object 170, the surface 170A (hereinafter also referred to as the upper surface 170A) corresponds to the surface on the magnetizing yoke 220 side, and the lower surface 170B corresponds to the surface on the back yoke 210 side. Therefore, as shown in FIG.
  • the inner peripheral region is an N pole on the upper surface of the magnetized portion 172 of the detected object 170 (hereinafter, indicated by the same reference numeral as the upper surface 170A of the detected object 170).
  • a boundary line that is a boundary where the direction of the magnetic flux in the magnetized portion 172 is reversed is indicated by a symbol B3.
  • the magnetized portion 172 of the detected body 170 has a magnetic flux density on its upper surface 170A that is larger than a magnetic flux density on its lower surface (hereinafter, indicated by the same reference numeral as the lower surface 170B of the detected body 170). It is configured.
  • the optical module 130 is formed in a substrate shape in this example, and the optical module 130 and the disk 110 are formed on the lower surface of the substrate 16 so as to face a part of the slit array SA of the disk 110. It is fixed in parallel. Accordingly, the optical module 130 can move relative to the slit array SA in the circumferential direction as the disk 110 rotates.
  • a light source 131 an example of a light emitting element
  • a light receiving array PA are provided on the surface of the optical module 130 facing the disk 110, that is, the lower surface.
  • the light source 131 irradiates light to a part of the slit array SA that passes through the facing position.
  • the light source 131 is not particularly limited as long as it is a light source capable of irradiating light to the irradiation region.
  • an LED Light Emitting Diode
  • the light source 131 is formed as a point light source in which an optical lens or the like is not particularly disposed, and irradiates diffused light from the light emitting unit. In the case of a point light source, it is not necessary to be an exact point, and light can be emitted from a finite surface as long as it can be considered that diffuse light is emitted from a substantially point-like position in terms of design and operation principle.
  • the light source 131 has the effect of the slit array SA that passes through the facing position, although there are some influences such as a change in light amount due to deviation from the optical axis and attenuation due to a difference in optical path length. Since a part can be irradiated with diffused light, it is possible to irradiate the part almost uniformly with light. In addition, since condensing and diffusing by the optical element are not performed, errors due to the optical element are not easily generated, and it is possible to improve the straightness of the irradiation light to the slit array SA.
  • the light receiving array PA is disposed around the light source 131 and receives the reflected light from the opposing slit array SA (reflection slit).
  • the light receiving array PA has a plurality of light receiving elements (not shown).
  • each light receiving element for example, PD (Photodiode) can be used.
  • the light receiving element is not limited to the PD, and is not particularly limited as long as it can receive light emitted from the light source 131 and convert it into an electric signal.
  • the electrical signal generated by the light receiving element is output to the position data generation unit 140.
  • the magnetic detection unit 120 detects the magnetism (magnetic field) generated by the magnetized unit 172 of the detection target 170. And a detection element 122.
  • the magnetoresistive element 121 and the magnetic field detection element 122 are interposed through bearings with respect to the detected object 170 rotating with the shaft SH, the disk 110, and the hub 160 so as to be able to face a part of the upper surface 170A of the detected object 170. Instead, the lower surface of the substrate 16 is fixed in parallel with the disk 110.
  • the magnetoresistive element 121 and the magnetic field detection element 122 are mounted on the same substrate 16 as the optical module 130, but may be mounted on a different substrate from the optical module 130. In the present embodiment, the magnetoresistive element 121 and the magnetic field detection element 122 are arranged so as to be shifted from each other by approximately 90 degrees in the rotation direction of the detection target 170.
  • the magnetoresistive element 121 is disposed so as to be able to face a part of the position B3 on the upper surface 170A of the magnetized portion 172 at the origin position P of the disk 110. As described above, since the magnetized portion 172 exists in a rotation angle range of approximately 180 degrees, the magnetoresistive element 121 generates the magnetized portion 172 in a rotation angle range of approximately 180 degrees corresponding to the magnetized portion 172. , Specifically, a horizontal magnetic field (direction perpendicular to the rotational axis AX) is detected, and no magnetic field is detected in the remaining rotation angle range of approximately 180 degrees corresponding to the unmagnetized portion 173 ( The magnetic field detection amount is smaller than a predetermined threshold value).
  • the magnetoresistive element 121 detects a magnetic field that changes for one period when the disk 110 rotates once, and outputs a signal that becomes one period for each rotation of the disk 110.
  • the magnetoresistive element 121 consumes less power than the magnetic field detecting element 122 and detects a horizontal magnetic field as described above, and therefore leaks from a brake (not shown) of the motor M transmitted through the shaft SH. Less susceptible to magnetic flux.
  • the magnetoresistive element 121 has a larger setting space and higher cost than the magnetic field detecting element 122.
  • a magnetic field is generated in the rotation angle range of approximately 180 degrees, and no magnetic field is generated in the remaining rotation angle range of approximately 180 degrees, and the magnetoresistive element 121 is approximately 180 degrees. Since the magnetic field is detected only in the rotation angle range of the above and the magnetic field is not detected in the remaining rotation angle range of about 180 degrees, it is possible to output a signal having one cycle for each rotation of the disk 110. That is, it is possible to obtain a signal having one cycle for each rotation of the disk 110 without using a bias magnet.
  • the magnetoresistive element 121 is not particularly limited as long as it can detect a horizontal magnetic field.
  • Examples of the magnetoresistive element 121 include an MR (magnetoresistive effect) element, a GMR (giant magnetoresistive effect) element, a TMR (tunnel magnetoresistive effect: Tunnel MagnetoResistive element), and the like. It can be used.
  • the magnetic field detection element 122 is disposed so as to be able to face a part of the inner peripheral side region (region having the polarity of N pole) on the upper surface 170A of the magnetized portion 172.
  • the magnetic field detection element 122 may be arranged so as to be able to face a part of the outer peripheral side region (region having the polarity of the S pole) on the upper surface 170A of the magnetized portion 172.
  • the magnetic field detecting element 122 since the magnetized portion 172 exists in a rotation angle range of approximately 180 degrees, the magnetic field detecting element 122 generates the magnetized portion 172 in a rotation angle range of approximately 180 degrees corresponding to the magnetized portion 172.
  • Magnetic field to be detected specifically, a magnetic field in a vertical direction (a direction parallel to the rotation axis AX) is detected, and a magnetic field is not detected in the remaining rotation angle range of about 180 degrees corresponding to the unmagnetized portion 173 (
  • the magnetic field detection amount is smaller than a predetermined threshold value).
  • the magnetic field detection element 122 detects a magnetic field that changes for one period when the disk 110 rotates once, and outputs a signal having one period for each rotation of the disk 110.
  • the magnetic field detecting element 122 requires a smaller installation space and is less expensive than the magnetoresistive element 121. However, since the magnetic field detection element 122 consumes more power than the magnetoresistive element 121 and detects the magnetic field in the vertical direction as described above, it is easily affected by the leakage magnetic flux.
  • the magnetic field detection element 122 is not particularly limited as long as it is configured to detect a vertical magnetic field.
  • a Hall element or the like can be used as the magnetic field detection element 122.
  • the signals output from the magnetoresistive element 121 and the magnetic field detection element 122 are acquired by the position data generation unit 140, and are used to detect the multi-rotation amount indicating how many times the disk 110 has rotated from the reference position.
  • Such multi-rotation amount detection is particularly effective when used for position detection when supplying backup power by turning off the power, for example.
  • FIG. 7 is an explanatory diagram for describing an example of the configuration of the position data generation unit according to the present embodiment.
  • the position data generation unit 140 includes an A-phase pulse generation unit 141 (an example of a first detection signal generation unit), a B-phase pulse generation unit 142 (an example of a second detection signal generation unit), It has a counter 143 (an example of a multi-rotation detection unit), a pulse generation circuit 144, a power supply control unit 145, and an absolute position signal generation unit 146.
  • A-phase pulse generation unit 141 an example of a first detection signal generation unit
  • B-phase pulse generation unit 142 an example of a second detection signal generation unit
  • It has a counter 143 (an example of a multi-rotation detection unit), a pulse generation circuit 144, a power supply control unit 145, and an absolute position signal generation unit 146.
  • the A-phase pulse generator 141 detects a signal from the magnetoresistive element 121, converts this signal into a rectangular wave signal, and generates an A-phase pulse signal a (an example of a first detection signal). As described above, since the magnetized portion 172 exists in a rotation angle range of approximately 180 degrees, the A-phase pulse signal a becomes a pulse signal for each rotation of the disk 110 with a duty ratio of 50%.
  • the B-phase pulse generation unit 142 detects a signal from the magnetic field detection element 122, converts this signal into a rectangular wave signal, and generates a B-phase pulse signal b (an example of a second detection signal).
  • a B-phase pulse signal b an example of a second detection signal.
  • the B-phase pulse signal b becomes a pulse signal for every rotation of the disk with a duty ratio of 50%.
  • the B-phase pulse signal b since the position of the magnetic field detecting element 122 is shifted by approximately 90 degrees from the position of the magnetoresistive element 121, the B-phase pulse signal b has a phase difference of about 90 degrees (predetermined from the A-phase pulse signal a). Of the phase difference).
  • the counter 143 counts the multi-rotation amount of the disk 110 based on the A-phase pulse signal a and the B-phase pulse signal b, and outputs it as a multi-rotation signal c. A specific counting method will be described later.
  • the pulse generation circuit 144 starts from that edge.
  • a power supply control pulse signal d having a predetermined pulse width is generated and output to the power supply control unit 145.
  • the power supply control unit 145 is turned on / off based on the power supply control pulse signal d from the pulse generation circuit 144, and supplies backup power to the magnetic field detection element 122 and the B-phase pulse generation unit 142 in a pulsed manner.
  • the magnetic field detection element 122 and the B-phase pulse generator 142 are driven for a predetermined time corresponding to the pulse width starting from the edge of the A-phase pulse signal a, and then the driving is terminated.
  • the predetermined time may be a time width that allows the counter 143 to detect the level of the B-phase pulse signal b.
  • the absolute position signal generation unit 146 generates an absolute position signal f representing the absolute position within one rotation of the disk 110 based on the output of the light receiving array PA. Specifically, in the plurality of light receiving elements included in the light receiving array PA, each light reception or non-light reception is handled as a bit, and represents the absolute position of the plurality of bits. Therefore, the light reception signals output from each of the plurality of light receiving elements are handled independently from each other in the absolute position signal generation unit 146, and the absolute position encrypted (encoded) into a serial bit pattern is determined by these absolute positions.
  • the absolute position signal f is generated by decoding from the combination of output signals.
  • the absolute position signal f and the multi-rotation signal c output from the counter 143 are combined, and the position data generator 140 outputs position data.
  • the power source switching unit 180 is configured as a switching element that switches based on a power source switching signal e from a detection circuit (not shown).
  • the external power supply includes the magnetoresistive element 121, the magnetic field detection element 122, the light source 131, the A phase pulse generation unit 141, the B phase pulse generation unit 142, the counter 143, and the pulse generation.
  • the signal is supplied to the circuit 144 and the absolute position signal generation unit 146.
  • the power switching unit 180 switches to the backup power source based on the power switching signal e.
  • the pulse generation circuit 144, the power supply control unit 145, and the power supply switching unit 180 correspond to an example of a power supply control unit.
  • the detection object 170 rotates together with the disk 110.
  • the magnetoresistive element 121 detects a magnetic field generated by the magnetized portion 172 of the detection target 170 and outputs a detection signal to the A-phase pulse generator 141.
  • the power supply control unit 145 is always ON, and external power is always supplied to the magnetic field detection element 122 and the B-phase pulse generation unit 142.
  • the magnetic field detection element 122 detects a magnetic field generated by the magnetized portion 172 of the detection target 170 and outputs a detection signal to the B-phase pulse generation unit 142.
  • the A-phase pulse generation unit 141 and the B-phase pulse generation unit 142 amplify the input signals and convert them into rectangular wave signals, respectively, and generate the generated A-phase pulse signal a and B-phase pulse having a phase difference of 90 degrees.
  • the signal b is output to the counter 143.
  • FIG. 8A and 8B show examples of waveforms of the A-phase pulse signal a and the B-phase pulse signal b at this time.
  • FIG. 8A shows a waveform during forward rotation
  • FIG. 8B shows a waveform during reverse rotation.
  • the A-phase pulse signal a and the B-phase pulse signal b are at the “H” level when a magnetic field is detected, and when the magnetic field is not detected (the detected amount of the magnetic field is less than a predetermined threshold value).
  • the rotation direction of the disk 110 is forward rotation in the clockwise direction and reverse rotation in the counterclockwise direction as shown in FIG.
  • the A-phase pulse signal a becomes a rising edge and the B-phase pulse signal b becomes “L”. Level.
  • the counter 143 increments the multi-rotation amount by adding 1 to the multi-rotation amount data.
  • counting is not performed.
  • the counter 143 subtracts 1 from the multi-rotation amount data and counts down the multi-rotation amount.
  • the count is not performed because it is not the origin position P of the disk 110.
  • the counter 143 outputs the multi-rotation amount data counted in this way as a multi-rotation signal c.
  • the above counting method is an example in the case of the configuration aspect of the present embodiment, and is not limited to this.
  • the detection object 170 is arranged at a position where the position B1 is shifted from the origin position P by 180 degrees, the correspondence relationship between the forward rotation and the reverse rotation is opposite to the above, and FIG. FIG. 8A shows the waveform during reverse rotation.
  • the way of counting the multi-rotation amount by the counter 143 is appropriately changed according to the configuration.
  • the light receiving array PA receives the light emitted from the light source 131 and reflected by the slit array SA, and outputs the received light signal to the absolute position signal generation unit 146.
  • the absolute position signal generation unit 146 generates an absolute position signal f representing the absolute position within one rotation of the disk 110 based on the input signal.
  • the power source switching unit 180 is switched to the backup power source side by a power source switching signal e from a detection circuit (not shown).
  • the backup power source is switched, the power source is not supplied to the light source 131 and the absolute position signal generation unit 146, and the backup power source is supplied to the magnetoresistive element 121, the A-phase pulse generation unit 141, the counter 143, and the pulse generation circuit 144. .
  • the pulse generation circuit 144 when detecting the edge of the A-phase pulse signal a, the pulse generation circuit 144 generates a power supply control pulse signal d having a predetermined pulse width generated from the edge as a starting point, and outputs a pulse-like signal via the power supply control unit 145. Power is supplied to the magnetic field detection element 122 and the B-phase pulse generator 142.
  • FIGS. 9A and 9B show examples of waveforms of the A-phase pulse signal a, the B-phase pulse signal b, and the power control pulse signal d at this time.
  • FIG. 9A shows a waveform during forward rotation
  • FIG. 9B shows a waveform during reverse rotation.
  • the Ton period in which the power control pulse signal d is at “H” level is a period in which backup power is supplied to the magnetic field detection element 122 and the B-phase pulse generator 142, and the power control pulse signal d is at “L” level.
  • the Toff period is a period in which the backup power is not supplied to the magnetic field detection element 122 and the B-phase pulse generation unit 142. Therefore, the B-phase pulse signal b is generated by the B-phase pulse generator 142 only during the Ton period indicated by the solid line in FIGS. 9A and 9B.
  • the counter 143 detects the edge of the A-phase pulse signal a, it detects the level of the B-phase pulse signal b during the Ton period and counts the amount of multi-rotation.
  • the counting method is the same as that at the time of external power supply described above. That is, at the time of forward rotation, as shown in FIG. 9A, when the A-phase pulse signal a is at the rising edge and the B-phase pulse signal b is at “L” level, the counter 143 adds 1 to the multi-rotation amount data. Counts up the multi-rotation amount.
  • the time of reverse rotation as shown in FIG.
  • the counter 143 subtracts 1 from the multi-rotation amount data. Count down the multi-rotation amount. In the Ton period, the counter 143 is set to the shortest time width within a range in which the level of the B-phase pulse signal b (the portion indicated by the solid line in FIGS. 9A and 9B) can be detected in order to reduce the power consumption of the backup power supply. Is done.
  • the position data generation unit 140 outputs the multi-rotation signal c output from the counter 143 as position data.
  • the multi-rotation amount data is stored in a memory (not shown) or the like, and when the backup power source is switched to the external power source, the position data generation unit 140 reads the multi-rotation amount data from the memory and The position data may be output by combining with the position signal f.
  • the magnetized device 200 magnetizes the detected object 170 between the magnetized yoke 220 and the back yoke 210 as described above, and the magnetized portion 172 is manufactured. Then, the magnetized detection object 170 is fixed to the surface 110A of the disk 110 by the fixing member so that the surface on the magnetizing yoke 220 side is on the upper side and the surface on the back yoke 210 side is on the lower side. At this time, position adjustment is performed for centering the disk 110 and the detected object 170.
  • the fixing member fixes the surface 162A of the disk fixing part 162 of the hub 160 to the surface 110B of the disk 110 while fitting the bolt fastening part 163 of the hub 160 into the through hole 111 of the disk 110. At this time, position adjustment is performed for centering the disk 110 and the hub 160.
  • the detection object 170, the disk 110, and the hub 160 are assembled together.
  • the detected body 170 may be magnetized by the magnetizing device after the detected body 170, the disk 110, and the hub 160 are integrally assembled by the fixing device.
  • the shaft SH is inserted into the through-hole 161 in the detection target 170, the disk 110, and the hub 160 that are assembled together, and the bolt 14 is inserted into the through-holes 171, 111, 161, and the bolt hole 13 of the shaft SH. Screwed on.
  • the detection object 170, the disk 110, and the hub 160 assembled together are fixed to the shaft SH.
  • the detected body 170 is held by the rotating body R by being brought into contact with the disk 110 in the vertical direction and fixed by an adhesive.
  • the adhesive that protrudes from the gap between the detected object 170 and the disk 110 adheres to the magnetoresistive element 121, the magnetic field detecting element 122, and the optical module 130 (such as the light source 131 and the light receiving element) mounted on the substrate 16. If the rotating body R is attached to the seat surface 14A of the bolt 14 for fixing the rotating body R to the shaft SH, the detection accuracy may be lowered, the fastening failure may be caused, and the reliability of the encoder 100 is lowered.
  • the inner diameter L3 of the through hole 111 of the disk 110 is formed larger than the inner diameter L4 of the through hole 171 of the detected body 170. Even if the tolerance of the through hole 111 of the disk 110 and the tolerance of the through hole 171 of the detected object 170 are taken into consideration, the inner diameter L3 of the through hole 111 of the disk 110 is equal to the through hole 171 of the detected object 170.
  • the dimension difference is necessarily larger than the inner diameter dimension L4. That is, the inner peripheral surface 170C of the detection object 170 protrudes inward from the inner peripheral surface 110C of the disk 110.
  • the adhesive protruding from the gap between the detected object 170 and the disk 110 can be guided to flow downward along the inner peripheral surface 110C of the disk 110 by the action of surface tension.
  • the adhesive can be prevented from adhering to the substrate 16, the bolts 14, etc., and the reliability of the encoder 100 can be improved.
  • the outer diameter dimension of the detected object 170 is subject to certain restrictions in order to avoid interference with the optical module 130 (particularly when the encoder 100 is a “reflective” encoder as in the present embodiment).
  • the inner diameter L4 of the through hole 171 of the detected object 170 is made smaller than the inner diameter L3 of the through hole 111 of the disk 110, so that the outer diameter is not increased and the detected object 170 is attached.
  • the volume of the magnetic part 172 can be increased. Therefore, the detection accuracy by the magnetic detection unit 120 can be improved.
  • the rotating body R has a groove 190 formed at the inner circumferential end of the disk 110.
  • the rotating body R includes the hub 160 and the disk 110.
  • the hub 160 can be made of different materials such as metal and the disk 110 can be made of glass.
  • the degree of freedom in design can be improved.
  • the disk 110 when the disk 110 is fixed to the hub 160, it can be performed while adjusting the rotation center of the disk 110, so that highly accurate alignment can be easily performed.
  • the disk 110 is fixed to the disk fixing part 162 of the hub 160 by bonding while the bolt fastening part 163 of the hub 160 is fitted in the through hole 111 of the disk 110.
  • a predetermined gap is previously provided between the stepped portion 164 of the hub 160 and the inner peripheral surface 110C of the disk 110 as an adjustment allowance. Is formed.
  • this gap is used as the groove 190 that also functions as an adhesive accumulation groove, it is not necessary to newly form a groove in the hub 160. Therefore, the manufacturing process can be simplified and the cost can be reduced.
  • the stepped portion 164 of the hub 160 functions as a stopper that restricts the movement of the disk 110 by striking against the inner peripheral surface 110C of the disk 110 when adjusting the position of the disk 110 and the hub 160, but the height thereof is increased. If the height is too high, the protruding amount of the bolt fastening portion 163 with respect to the disk fixing portion 162 increases, and the head portion 14B of the bolt 14 may interfere with elements such as the magnetic detection portion 120.
  • the height dimension L1 of the stepped portion 164 is approximately half the thickness dimension L2 of the disk 110, so that interference between the bolt 14 and the element is avoided while sufficiently providing the function as the stopper. be able to.
  • the encoder 100 includes a light source 131 that irradiates the disk 110 with light and a light receiving element that receives the reflected light from the reflection slit formed on the disk 110. It is an encoder.
  • the “reflective” encoder can have a larger gap between the light source 131 and the light receiving element and the disk 110 than the so-called “transmissive” encoder. Thereby, the influence of the fluctuation
  • the gap between each element such as the magnetoresistive element 121 and the magnetic field detection element 122 of the magnetic detection unit 120 provided on the same substrate as the light source 131 and the light receiving element is increased, the magnetic field is accurately detected. Therefore, it is necessary to increase the height direction (axial direction) dimension of the magnetized portion 172 of the detection object 170. Further, by forming the light source 131 and the light receiving element as one component as one optical module 130, the thickness of the optical module 130 becomes larger than that of other elements. As a result, when the installation positions of the detection object 170 and the optical module 130 overlap in the radial direction, there is a possibility that they interfere with each other in the height direction.
  • the inner diameter L4 of the through-hole 171 of the detected object 170 is formed smaller than the inner diameter L3 of the through-hole 111 of the disk 110, and the detected object 170 is inner peripheral than the disk 110. Provide to protrude to the side. As a result, the outer diameter of the detected body 170 can be reduced without reducing the volume of the magnetized portion 172 of the detected body 170, and interference with the optical module 130 can be avoided. Therefore, it is possible to realize a “reflective” encoder capable of accurately detecting a multi-rotation amount.
  • the magnetized portion 172 is formed in this embodiment. It is not limited to the case where the magnetic flux density of the upper surface 170A described in the embodiment is configured to be larger than the magnetic flux density of the lower surface 170B.
  • the magnetized portion 172 may be configured such that the magnetic flux density on the upper surface 170A is equal to the magnetic flux density on the lower surface 170B.
  • the magnetized portion 172 may be configured such that the magnetic flux density on the upper surface 170A is smaller than the magnetic flux density on the lower surface 170B.
  • the detected object 170 is used in the present embodiment. It is not limited to the case where the magnetized portion 172 is fixed to the disk 110 as described in the embodiment so that the surface on the magnetizing yoke 220 side is the upper side and the surface on the back yoke 210 side is the lower side.
  • the detected body 170 may be fixed to the disk 110 such that the surface on the magnetizing yoke 220 side is on the lower side and the surface on the back yoke 210 side is on the upper side.
  • the disk 110 is used in this embodiment.
  • the present invention is not limited to the case where the glass is formed.
  • the disk 110 may be formed of a material other than glass (for example, metal or resin).
  • the reflection slit is made by roughening a portion that does not reflect light by sputtering or applying a material having a low reflectance. May be formed.
  • the method of forming the reflective slit is not limited to this example.
  • the detected object 170 is used in the present embodiment.
  • the present invention is not limited to the case where the magnetized portion 172 is configured to generate a magnetic field in the rotation angle range of about 180 degrees described in the embodiment.
  • the detected object 170 may be configured such that the magnetized portion generates a magnetic field within a rotation angle range smaller than 180 degrees and no magnetic field is generated in the remaining rotation angle range.
  • the detected object 170 may be configured such that the magnetized portion generates a magnetic field within a rotation angle range larger than 180 degrees and no magnetic field is generated in the remaining rotation angle range.
  • the magnetoresistive element 121 and the magnetic field detection element The number 122 is not limited to the case where the objects to be detected 170 described in the present embodiment are arranged so as to be shifted from each other by approximately 90 degrees.
  • the magnetoresistive element 121 and the magnetic field detection element 122 may be arranged so as to be shifted from each other by an angle smaller than 90 degrees in the rotation direction of the detection target 170 or so that the positions in the rotation direction coincide with each other. .
  • the magnetoresistive element 121 and the magnetic field detection element 122 may be arranged so as to be shifted from each other by an angle larger than 90 degrees in the rotation direction of the detection target 170.
  • the magnetic detection unit 120 performs the present embodiment.
  • the present invention is not limited to the case where one magnetoresistive element 121 and one magnetic field detecting element 122 described in the embodiment are provided.
  • the magnetic detection unit 120 may include two or more magnetoresistive elements and may or may not include one magnetic field detection element.
  • the magnetic detection unit 120 may have two or more magnetic field detection elements and may or may not have one magnetoresistive element.
  • the magnetized portion 172 of the detection object 170 is configured such that the magnetic flux density on the upper surface 170A is greater than the magnetic flux density on the lower surface 170B.
  • the present embodiment is configured such that a magnetic field is generated in a rotation angle range of approximately 180 degrees and no magnetic field is generated in the remaining rotation angle range of approximately 180 degrees. Therefore, even if the magnetic flux generated from the detected object 170 is reduced due to this configuration, the magnetized portion 172 of the detected object 170 has a magnetic flux density on the upper surface 170A of the lower surface 170B. By being configured to be larger than the above, it is possible to compensate for the decrease in the magnetic flux.
  • the magnetized portion 200 is manufactured by magnetizing the unmagnetized detection target 170 that is a magnet material between the magnetized yoke 220 and the back yoke 210 in the magnetizing apparatus 200.
  • the magnetized portion 172 manufactured in this way the magnetic flux density on the surface on the magnetized yoke 220 side is larger than the magnetic flux density on the surface on the back yoke 210 side. Therefore, the detected body 170 is fixed to the disk 110 so that the surface of the magnetized portion 172 on the magnetized yoke 220 side is on the upper side and the surface on the back yoke 210 side is on the lower side.
  • the magnetized portion 172 can be configured so that the magnetic flux density on the upper surface 170A is larger than the magnetic flux density on the lower surface 170B. Therefore, a decrease in detection accuracy due to demagnetization of the magnetized portion 172 can be suppressed.
  • the rotating body R has the hub 160 and the disk 110 in particular.
  • the disk 110 is made of glass, and the detection object 170 is fixed to the surface 110A, and the hub 160 is fixed to the surface 110B. Since the hub 160 is required to be strong, it is made of metal in this example, and is connected to the shaft SH. With such a configuration, the glass disk 110 having a lower thermal conductivity than that of the metal can be interposed between the hub 160 and the detection object 170. As a result, since heat generated in the shaft SH of the motor M or the like can be prevented from being transmitted from the hub 160 to the magnetized portion 172 of the detected object 170, demagnetization of the magnetized portion 172 is reduced, and detection accuracy is reduced. Further suppression can be achieved.
  • the encoder 100 is fixed so that the magnetic detection unit 120 on the fixed side is fixed to the detection target 170 on the rotation side, the disk 110, and the hub 160 without bearings.
  • This is a “built-in type” encoder.
  • the disk 110 is directly connected to the shaft SH via the hub 160, so that the fixed side is fixed to the rotating side via a bearing compared to a so-called “complete type” encoder.
  • the magnetized portion 172 of the detection object 170 is easily affected by the heat generated in the shaft SH.
  • the glass disk 110 having a small thermal conductivity is interposed between the hub 160 and the magnetized portion 172 of the object 170 to be detected. Even in the “built-in type” encoder in which the shaft SH is close, heat transfer from the hub 160 to the magnetized portion 172 of the detection object 170 can be suppressed. Therefore, it is possible to realize a “built-in type” encoder capable of accurately detecting the amount of multiple rotations.
  • a non-magnetized object 170 to be detected which is a magnet material
  • the detected object 170 including the magnetized portion 172 manufactured in this way is fixed to the upper surface 110A of the disk 110 with the vertical direction as it is.
  • the reason why the vertical direction is left as it is is that if the vertical direction is changed, a process of turning over the detected object 170 is newly required, which complicates the manufacturing process and the manufacturing apparatus, and the operator detects the detected object.
  • the surface on the back yoke 210 side having a lower magnetic flux density than the surface on the magnetizing yoke 210 side is positioned on the upper side. Therefore, when the magnetized portion 172 is demagnetized, the magnetic detection unit 120 is rotated at multiple speeds. There is a possibility that a magnetic flux sufficient for detection cannot be obtained and the detection accuracy is lowered.
  • the encoder 100 includes a light source 131 that irradiates the disk 100 with light and a light receiving element that receives the reflected light from the reflection slit formed on the disk 110. It is an encoder.
  • the “reflective” encoder can have a larger gap between the light source 131 and the light receiving element and the disk 110 than the so-called “transmissive” encoder. As a result, there is an advantage that the influence of the fluctuation of the gap accompanying the rotation of the disk 110 due to a manufacturing error or the like can be reduced.
  • the gap between the magnetic detector 120 provided on the same substrate 16 as the light source 131 and the light receiving element and the magnetized portion 172 of the detected object 170 is also increased, the height of the detected object 170 is detected in order to accurately detect the magnetic field. It is necessary to increase the dimension in the vertical direction (axial direction). As a result, the difference in magnetic flux density between the upper surface 170A and the lower surface 170B of the detection object 170 increases, and particularly in the case of a “reflective” encoder, the magnetic detection unit 120 when the magnetized portion 172 is demagnetized. However, the possibility that a sufficient magnetic field cannot be obtained increases, and there is a problem that a decrease in detection accuracy becomes obvious.
  • the vertical direction of the detected object 170 after magnetization is changed so that the surface on the magnetized yoke 220 side is the upper side and the surface on the back yoke 210 side is the lower side. Then, the detected object 170 is fixed to the disk 110.
  • the height direction (axial direction) dimension of the detection target 170 is relatively large, a decrease in detection accuracy due to demagnetization of the magnetized portion 172 can be suppressed. Therefore, it is possible to realize a “reflective” encoder capable of accurately detecting the amount of multiple rotations.
  • the through hole 111 of the disk 110 described in this embodiment is used.
  • the inner diameter dimension L3 of the through hole 111 of the disk 110 and the inner diameter dimension L4 of the through hole 171 of the detection object 170 may be formed to be equal.
  • the inner diameter L3 of the through hole 111 of the disk 110 may be formed smaller than the inner diameter L4 of the through hole 171 of the detection target 170.
  • the rotating body R is different from that described in the present embodiment.
  • the present invention is not limited to the case where the body has the hub 160 and the disk 110.
  • the rotating body R may be composed of one member.
  • the height of the stepped portion 164 described in the present embodiment is not limited to the case where the dimension L1 is configured to be approximately half the thickness dimension L2 of the disk 110.
  • the height L1 of the stepped portion 164 may be configured to be smaller or larger than half of the thickness L2 of the disk 110.
  • the detected object 170 has been described in this embodiment.
  • the present invention is not limited to the case where the magnetized portion 172 is configured to generate a magnetic field within a rotation angle range of approximately 180 degrees.
  • the magnetoresistive element 121 and the magnetic field detecting element 122 are The present invention is not limited to the case where the detection target 170 described in the embodiment is arranged so as to be shifted from each other by approximately 90 degrees in the rotation direction.
  • the magnetic detection unit 120 has been described in this embodiment.
  • the present invention is not limited to the case of having one magnetoresistive element 121 and one magnetic field detecting element 122.
  • the magnetized portion 172 generates a magnetic field in the rotation angle range of approximately 180 degrees, and no magnetic field is generated in the remaining rotation angle range of approximately 180 degrees.
  • the magnetic detection unit 120 detects the magnetic field in a rotation angle range of approximately 180 degrees where the magnetizing unit 172 generates a magnetic field, and does not detect the magnetic field in the remaining rotation angle range of approximately 180 degrees.
  • a signal having one cycle is output every time.
  • the counter 143 detects the multi-rotation amount of the disk 110 by counting a two-phase signal having a phase difference of about 90 degrees obtained from the magnetoresistive element 121 and the magnetic field detection element 122.
  • Such a configuration can be realized by magnetizing within a rotation angle range of approximately 180 degrees of an unmagnetized detection object 170 that is a magnet material provided over the entire rotation angle range of 360 degrees. it can. As a result, it is not necessary to magnetize the entire area of the non-magnetized object 170 to be detected, and it is only necessary to perform the magnetization within a rotation angle range of approximately 180 degrees. Can be improved. In particular, when a magnetic field is generated in a rotation angle range of approximately 180 degrees, the boundary that is the boundary between the occurrence and non-occurrence of the magnetic field becomes two target positions B1 and B2 in the rotation angle of 360 degrees.
  • the count-up / down determination can be made from the two detection results of the 0-degree position and the 180-degree position, and a more accurate number of rotations can be calculated (for example, counting up and down on one side, checking on the other side, etc.) ).
  • the magnetic field is generated in the rotation angle range of about 180 degrees, and the magnetic flux generated from the detection target 170 due to the configuration that the magnetic field is not generated in the remaining rotation angle range of about 180 degrees.
  • the magnetized portion 172 of the detection object 170 is configured such that the magnetic flux density on the upper surface 170A is larger than the magnetic flux density on the lower surface 170B. The decrease in the magnetic flux can be compensated.
  • the magnetized portion 172 is a magnet material magnetized in a rotation angle range of approximately 180 degrees.
  • an unmagnetized detected object 172 made of a magnet material is formed in an annular shape, and the detected object 172 is provided over the entire rotation angle range of 360 degrees, and only in a rotation angle range of approximately 180 degrees.
  • the remaining 180 degrees range is an unmagnetized magnet material. By doing so, it is only necessary to perform magnetization in a rotation angle range of approximately 180 degrees, so that the magnetization process can be simplified and productivity can be improved as compared with the case where magnetization is performed over the entire area of the detected object 172. Can be improved.
  • the magnetizing apparatus 200 can be reduced in size.
  • the magnetoresistive element 121 is used as one of the magnetic detectors 120 that detect the magnetic field generated by the magnetized portion 172. Since the magnetoresistive element 121 consumes less power than the magnetic field detecting element 122, the life of the backup power supply can be extended, and the horizontal magnetic field is detected, so that the influence of leakage magnetic flux from the brake or the like transmitted through the shaft SH is affected. There is an advantage that it is difficult to receive.
  • the direction of the magnetic field In order to detect this, it is necessary to provide a bias magnet.
  • the bias magnet is attached to a magnet mounting recess formed in the magnetoresistive element.
  • the bias magnet and the recess are very small, so that the workability is poor, and the bias magnet is expensive, resulting in a high part cost. There is a problem.
  • the magnetoresistive element cannot detect the direction of the magnetic field, so that a detection signal of two cycles is output for each rotation of the disk 110.
  • the counter 143 requires twice as much signal processing capability.
  • the magnetized portion 172 generates a magnetic field in the rotation angle range of approximately 180 degrees, and no magnetic field is generated in the remaining rotation angle range of approximately 180 degrees.
  • the magnetoresistive element 121 detects a magnetic field only in a rotation angle range of approximately 180 degrees and does not detect a magnetic field in the remaining rotation angle range of approximately 180 degrees, so that one cycle is made for each rotation of the disk 110. Output a signal. As a result, a signal of one cycle can be obtained for each rotation of the disk 110 without using a bias magnet. Accordingly, it is possible to eliminate the work of attaching the bias magnet having poor workability, and it is possible to reduce the cost of parts because the bias magnet is unnecessary.
  • the magnetoresistive element 121 has advantages that it consumes less power than the magnetic field detection element 122 and is less susceptible to leakage magnetic flux from a brake or the like, but has a disadvantage that a large installation space is required and the cost is high.
  • the magnetic field detection element 122 has the advantages that the required installation space is small and the cost is lower than that of the magnetoresistive element 121, but has the disadvantage that the power consumption is large and it is easily affected by the leakage magnetic flux. Therefore, in the present embodiment, by configuring the magnetic detection unit 120 with both the magnetoresistive element 121 and the magnetic field detection element 122, it is possible to realize the magnetic detection unit 120 in which the mutual defects are offset.
  • the A-phase pulse generator 141 generates the A-phase pulse signal a based on the output of the magnetoresistive element 121.
  • the pulse generation circuit 144 supplies power to the magnetic field detection element 122 and the B-phase pulse generation unit 142 with a predetermined time width from the detected change.
  • the B-phase pulse generator 142 generates a B-phase pulse signal b having a phase difference of 90 degrees from the A-phase pulse signal a.
  • the counter 143 detects the multi-rotation amount of the disk 110 based on the A-phase pulse signal a and the B-phase pulse signal b.
  • the magnetized portion 172 is described in the present embodiment.
  • the present invention is not limited to the case where the magnetic flux density of the upper surface 170A is configured to be larger than the magnetic flux density of the lower surface 170B.
  • the detected object 170 described in this embodiment is used. Is not limited to the case where the magnetized portion 172 is fixed to the disk 110 such that the surface on the magnetized yoke 220 side is the upper side and the surface on the back yoke 210 side is the lower side.
  • the disk 110 is made of the glass described in the present embodiment. It is not limited to the case where it forms by.
  • the through hole of the disk 110 described in the present embodiment is used. It is not limited to the case where the inner diameter dimension L3 of 111 is formed larger than the inner diameter dimension L4 of the through hole 171 of the detection object 170.
  • the rotating body R is described in the present embodiment.
  • the present invention is not limited to the case where the hub 160 and the disk 110 are provided separately.
  • the height of the stepped portion 164 described in the present embodiment is high.
  • the present invention is not limited to the case where the length L1 is configured to be approximately half the thickness L2 of the disk 110.
  • the detected object 170 is magnetized in a portion (magnetized portion 172) that is magnetized in a rotation angle range of approximately 180 degrees and a portion that is not magnetized in the remaining rotation angle range of approximately 180 degrees (not yet). And a magnet material including a magnetized portion 173).
  • the present invention is not limited to this example in order to obtain the effects described in the above embodiment.
  • the object to be detected may be configured by an arc-shaped magnet having a central angle of approximately 180 degrees and a non-magnetic material that is disposed on the opposite side in the rotation direction of the magnet and has the same shape as the magnet. Good.
  • FIG. 10 is a plan view illustrating an example of the configuration of the detection target and the magnetic detection unit according to this modification.
  • the detected object 170 ′ according to this modification is formed in substantially the same shape as the detected object 170, that is, in an annular shape, and is provided over the entire rotation angle range of 360 degrees. It has been.
  • a through hole 171 is provided in a substantially central portion (inner side) of the detection object 170 ′.
  • the detected object 170 ′ includes a magnet 172 ′ manufactured by magnetizing an entire area of the arc-shaped magnet material having a center angle of approximately 180 degrees (a rotation angle range of approximately 180 degrees), and a magnet 172. It is arranged on the opposite side in the rotation direction of 'and has a non-magnetic material 173' having substantially the same shape as the magnet 172 '.
  • the magnet 172 generates a magnetic field.
  • the magnetic pole pattern of the magnet 172 ' is the same as the magnetized portion 172 of the detection object 170 described above.
  • a boundary line which is a boundary where the direction of the magnetic flux in the magnet 172 'is reversed is indicated by a symbol B3.
  • the non-magnetic material 173 'does not generate a magnetic field.
  • the through hole 171 of the detection object 170 ′ can be said to be a through hole of the magnet 172 ′ or the nonmagnetic material 173 ′.
  • the boundary which is the boundary of the presence or absence of magnetism in the detected object 170 ' is two positions B1 and B2 which are substantially contrasted at a rotation angle of 360 degrees.
  • the detected body 170 ′ is arranged so that one of the positions B ⁇ b> 1 and B ⁇ b> 2 (in this example, the position B ⁇ b> 1) substantially coincides with the origin position P described above.
  • the magnetoresistive element 121 detects the magnetic field generated by the magnet 172 ′ in the rotation angle range of approximately 180 degrees corresponding to the magnet 172 ′, and the remaining rotation angle of approximately 180 degrees corresponding to the nonmagnetic material 173 ′. No magnetic field is detected in the range.
  • the magnetoresistive element 121 detects a magnetic field that changes for one period when the disk 110 rotates once, and outputs a signal that becomes one period for each rotation of the disk 110.
  • the magnetic field detection element 122 detects the magnetic field generated by the magnet 172 ′ in the rotation angle range of approximately 180 degrees corresponding to the magnet 172 ′, and the remaining rotation angle of approximately 180 degrees corresponding to the nonmagnetic material 173 ′. No magnetic field is detected in the range.
  • the magnetic field detection element 122 detects a magnetic field that changes for one period when the disk 110 rotates once, and outputs a signal having one period for each rotation of the disk 110.
  • the magnet 172 ' is formed in an arc shape having a central angle of approximately 180 degrees.
  • a nonmagnetic material 173 ′ having substantially the same shape as the magnet 172 ′ is provided on the opposite side in the rotation direction of the magnet 172 ′.
  • the detected object 170 ′ is arranged on the opposite side in the rotation direction of the magnet MG with the arc-shaped magnet 172 ′ having a central angle of approximately 180 degrees, and the magnet 172 ′.
  • the non-magnetic material 173 ′ has substantially the same shape.
  • the present invention is not limited to this example in order to obtain the effects and the like described in the above embodiments and modifications.
  • the object to be detected may be composed of only an arc-shaped magnet having a central angle of approximately 180 degrees.
  • the detection object 170 is directly fixed to the disk 110.
  • the present invention is not limited to this example in order to obtain the effects described in the above embodiments and modifications, and the detected object 170 may be indirectly connected to the disk 110.
  • the detected object 170 or the detected object 170 ′ is formed in an annular shape, and an approximately half arc-shaped region is the magnetized portion 172 or the magnet 172 ′.
  • the remaining arc-shaped region is the non-magnetized portion 173 or the non-magnetic material 173 ′.
  • the present invention is not limited to this example in order to obtain the effects and the like described in the above embodiments and modifications.
  • the object to be detected may be formed in a disc shape, and a substantially half of the semicircular region may be a magnetized portion or a magnet, and the remaining semicircular region may be an unmagnetized portion or a nonmagnetic material.
  • the detected object is formed of an arc-shaped magnet.
  • the present invention is not limited to this example in order to obtain the effects described in the above-described embodiments and modifications, and the detection target may be formed of a semicircular magnet.
  • the magnetoresistive element 121 detects the magnetic field generated by the magnetized portion 172 in the rotation angle range of approximately 180 degrees, and does not detect the magnetic field in the remaining rotation angle range of approximately 180 degrees.
  • a signal having one cycle is output for each rotation of the disk 110, and the multi-rotation amount of the disk 110 is detected based on this signal or the like.
  • the present invention is not limited to this example in order to obtain the effects and the like described in the above embodiments and modifications.
  • a signal having two cycles is output for each rotation of the disk 110, and the disk is based on this signal or the like. 110 may be detected.
  • the encoder 100 is described as an example of a so-called “reflective” encoder in which the light receiving array PA is disposed on the same side as the light source 131 with respect to the disk 110.
  • a so-called “transmission type” encoder in which the light receiving array PA is disposed on the opposite side of the light source 131 with respect to the disk 110 may be used as the encoder.
  • the slit array SA may be formed as a transmission hole, or a portion other than the slit may be roughened by sputtering or the like, or a material having low transmittance may be applied.
  • the encoder 100 is the so-called “built-in type” encoder 100 in which the rotating disk 110 is directly connected to the shaft SH has been described as an example.
  • the present invention is not limited to this example. That is, a so-called “complete type” encoder in which the disk 110 is connected to a shaft dedicated to the encoder and the shaft can be connected to the motor M or the like may be used as the encoder. In this case, the hub is indirectly connected to the shaft SH.
  • a plurality of reflective slits having an incremental pattern in the circumferential direction may be provided on the disk 110.
  • the incremental pattern is a pattern that is regularly repeated at a predetermined pitch. This incremental pattern is different from an absolute pattern that represents an absolute position using each of the presence / absence of detection by a plurality of light receiving elements as a bit, and differs depending on the sum of detection signals by at least one or more light receiving elements. Represents the position. Therefore, the incremental pattern does not represent the absolute position of the motor M, but can represent the position with very high accuracy compared to the absolute pattern.
  • FIGS. 1, 2, and 7 show an example of the signal flow, and do not limit the signal flow direction.

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Abstract

Le problème décrit par la présente invention consiste à améliorer la fiabilité. La solution de l'invention porte sur un codeur (100), qui comprend un corps rotatif (R) et un objet à détecter (170) ayant un trou traversant (171) et maintenu sur le corps rotatif (R). Le corps rotatif (R) comprend un disque (110) ayant un trou traversant (111) et sur lequel est fixé l'objet à détecter (170) par le fait qu'il est mis en contact et collé dans la direction du centre d'arbre de rotation (AX). Le diamètre intérieur (L3) du trou traversant (111) dans le disque (110) est formé pour être plus grand que le diamètre intérieur (L4) du trou traversant (171) de l'objet à détecter (170). De plus, le corps rotatif (R) présente une gorge (190) formée sur le bord périphérique intérieur du disque (110).
PCT/JP2012/074770 2012-09-26 2012-09-26 Codeur, procédé de fabrication de codeur et servo-système WO2014049743A1 (fr)

Priority Applications (2)

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CN201280075798.5A CN104620081A (zh) 2012-09-26 2012-09-26 编码器、编码器的制造方法、伺服系统
PCT/JP2012/074770 WO2014049743A1 (fr) 2012-09-26 2012-09-26 Codeur, procédé de fabrication de codeur et servo-système

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US11609106B2 (en) * 2018-07-17 2023-03-21 Mitsubishi Electric Corporation Reflective optical encoder comprising a hub with an adhesive surface with a step structure
CN113050699B (zh) * 2020-08-30 2024-01-12 惠州华阳通用电子有限公司 一种基于磁编码器的控制方法及装置

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JPS59104068U (ja) * 1982-12-29 1984-07-13 アルプス電気株式会社 回転数検出装置
JPH0290017A (ja) * 1988-09-28 1990-03-29 Yaskawa Electric Mfg Co Ltd 多回転式絶対値エンコーダ
JPH0397617U (fr) * 1989-10-09 1991-10-08
JPH0478561U (fr) * 1990-11-20 1992-07-08
JP2002353029A (ja) * 2001-05-28 2002-12-06 Yaskawa Electric Corp 着磁治具

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DE112004002011B4 (de) * 2003-10-24 2011-06-22 Kabushiki Kaisha Yaskawa Denki, Fukuoka Magnetische Kodiereinrichtung und Stellglied
WO2006085569A1 (fr) * 2005-02-10 2006-08-17 Matsushita Electric Industrial Co., Ltd. Dispositif de detection d’angle de rotation et procede de correction d’angle de rotation
JP4868753B2 (ja) * 2005-03-18 2012-02-01 ハイデンハイン株式会社 多回転型エンコーダおよびその製造方法
CN101175974B (zh) * 2005-05-10 2011-03-30 日本精工株式会社 磁编码器和具有磁编码器的滚柱轴承

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Publication number Priority date Publication date Assignee Title
JPS59104068U (ja) * 1982-12-29 1984-07-13 アルプス電気株式会社 回転数検出装置
JPH0290017A (ja) * 1988-09-28 1990-03-29 Yaskawa Electric Mfg Co Ltd 多回転式絶対値エンコーダ
JPH0397617U (fr) * 1989-10-09 1991-10-08
JPH0478561U (fr) * 1990-11-20 1992-07-08
JP2002353029A (ja) * 2001-05-28 2002-12-06 Yaskawa Electric Corp 着磁治具

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