WO2016021401A1 - Magnetic linear encoder - Google Patents

Magnetic linear encoder Download PDF

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Publication number
WO2016021401A1
WO2016021401A1 PCT/JP2015/070704 JP2015070704W WO2016021401A1 WO 2016021401 A1 WO2016021401 A1 WO 2016021401A1 JP 2015070704 W JP2015070704 W JP 2015070704W WO 2016021401 A1 WO2016021401 A1 WO 2016021401A1
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WO
WIPO (PCT)
Prior art keywords
magnetic
permanent magnet
linear encoder
scale
sensor device
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Application number
PCT/JP2015/070704
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French (fr)
Japanese (ja)
Inventor
克也 森山
水嵜　康史
Original Assignee
日本電産サンキョー株式会社
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Application filed by 日本電産サンキョー株式会社 filed Critical 日本電産サンキョー株式会社
Priority to CN201580042297.0A priority Critical patent/CN106662470A/en
Publication of WO2016021401A1 publication Critical patent/WO2016021401A1/en

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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
    • G01D5/245—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 using a variable number of pulses in a train

Definitions

  • the present invention relates to a magnetic linear encoder that detects a magnetic field from a magnetic scale by a magnetic sensor device.
  • the magnetic linear encoder has a magnetic scale having a permanent magnet and a magnetic sensor device having a magnetoresistive element, and detection by the magnetic sensor device when the magnetic scale and the magnetic sensor device move relative to each other. Based on the result, the relative position between the magnetic scale and the magnetic sensor device is detected.
  • the magnetic scale has, for example, a structure in which a permanent magnet and a protective sheet are laminated on a base plate (see Patent Document 1).
  • a rubber magnet in which magnetic powder is mixed with rubber is often used as a permanent magnet.
  • an object of the present invention is to provide a magnetic linear encoder capable of improving the magnetization accuracy of a permanent magnet of a magnetic scale.
  • a magnetic linear encoder includes a magnetic scale including a permanent magnet and a magnetic sensor device including a magnetoresistive element that detects a magnetic field from the magnetic scale.
  • the permanent magnet is formed with tracks in which N poles and S poles are alternately arranged along the relative movement direction of the magnetic sensor device and the magnetic scale, It consists of a magnetic coating film formed on one surface of a metal base plate containing magnetic powder and resin.
  • the permanent magnet used for the magnetic scale is made of a magnetic coating film containing magnetic powder and resin, it is possible to obtain high flatness with good workability as compared with a rubber magnet.
  • a metal base plate is used, it is easy to obtain high flatness in the permanent magnet. Therefore, since the magnetization accuracy of the permanent magnet of the magnetic scale can be improved, the resolution and the like of the magnetic linear encoder can be improved.
  • the thickness of the magnetic coating film is preferably 400 ⁇ m to 500 ⁇ m. According to such a configuration, it is possible to appropriately magnetize the magnetic coating film, so that the resolution can be improved and the hysteresis error can be reduced.
  • the base plate is preferably made of a nonmagnetic metal. According to such a configuration, even if magnetization is performed by the ring gate, the influence of the base plate is hardly generated.
  • the permanent magnet preferably has an easy axis of magnetization of the magnetic powder oriented in a film thickness direction of the magnetic coating film. According to this configuration, it is possible to improve the resolution and reduce the hysteresis error.
  • the magnetic powder is preferably ferrite magnetic powder. According to such a configuration, it is possible to improve the resolution when the position or the like is obtained by interpolation.
  • the permanent magnet preferably contains strontium ferrite and barium ferrite as the ferrite-based magnetic powder.
  • the present invention is effective when applied to an open type magnetic linear encoder in which the magnetic sensor device and the magnetic scale are relatively moved in a non-contact state.
  • the permanent magnet preferably has an exposed surface on the magnetic sensor device side. According to such a configuration, it is possible to ensure a wide interval between the magnetic sensor device and the magnetic scale, so that contact between the permanent magnet and the magnetic sensor device hardly occurs.
  • a distance between the magnetoresistive element and the permanent magnet is 0.15 mm to 0.35 mm. According to this configuration, a wide interval between the magnetic sensor device and the magnetic scale can be secured, and even in that case, sufficient resolution can be obtained.
  • the tracks are provided in a plurality of rows in a direction intersecting the relative movement direction, and two adjacent tracks in the plurality of rows have N poles in the relative movement direction. It is preferable that the S pole is deviated. According to such a configuration, a strong rotating magnetic field is generated at the track boundary portion of the edge portion in the track width direction. Therefore, the detection accuracy of the magnetic linear encoder can be improved by making the sensor surface of the magnetic sensor device face the boundary portion of the track.
  • the magnetoresistive element can employ a configuration for detecting a rotating magnetic field of the permanent magnet. According to such a configuration, a sine wave component can be stably obtained even when the gap between the magnetic scale and the magnetic sensor device is narrow.
  • the permanent magnet used for the magnetic scale is made of a magnetic coating film containing magnetic powder and resin, a higher flatness can be obtained compared to a rubber magnet.
  • a metal base plate since a metal base plate is used, it is easy to obtain high flatness in the permanent magnet. Therefore, since the magnetization accuracy of the permanent magnet of the magnetic scale can be improved, the resolution and the like of the magnetic linear encoder can be improved.
  • FIG. 1 is an explanatory diagram showing the appearance and the like of a magnetic linear encoder to which the present invention is applied.
  • FIG. 2 is an explanatory view showing a main part of a magnetic linear encoder to which the present invention is applied.
  • FIGS. 2A, 2B, and 2C are schematic cross sections showing the structure of the main part of the magnetic sensor device. It is a figure, its schematic perspective view, and a schematic plan view.
  • FIG. 3 is an explanatory diagram showing the magnetic characteristics of the magnetic scale of the magnetic linear encoder to which the present invention is applied.
  • FIGS. 3A, 3B, and 3C show the direction of the magnetic field in a plan view. It is explanatory drawing at the time, explanatory drawing when it sees diagonally, and explanatory drawing when it sees from the side.
  • the magnetic linear encoder 100 has a magnetic scale 9 extending in one direction and a magnetic sensor device 1 arranged in the vicinity of the magnetic scale 9.
  • one of the magnetic scale 9 and the magnetic sensor device 1 is held by a fixed body, and the other is held by a moving body.
  • the magnetic sensor device 1 is held by a fixed body, and the magnetic scale 9 is held by a moving body.
  • the magnetic scale 9 is formed with tracks in which N poles and S poles are alternately arranged along the longitudinal direction (the relative movement direction of the magnetic sensor device 1 and the magnetic scale 9).
  • the magnetic sensor device 1 detects the position or the like when the magnetic scale 9 (moving body) moves in the longitudinal direction of the magnetic scale 9 by detecting the direction of the rotating magnetic field formed on the surface of the magnetic scale 9.
  • the magnetic sensor device 1 includes a holder 6 made of a substantially rectangular parallelepiped aluminum die-cast product, a rectangular cover 68 covering the opening of the holder 6, and a cable 7 extending from the holder 6.
  • a cable insertion hole 69 is formed on the side surface of the holder 6, and the cable 7 is drawn from the cable insertion hole 69.
  • the holder 6 has a reference surface 60 made of a flat surface protruding from the bottom surface of the holder 6 through a step on the bottom surface facing the magnetic scale 9. Is formed.
  • An opening 65 is formed in the reference surface 60, and the magnetoresistive element 25 formed on the rigid substrate 10 such as a glass substrate, a silicon substrate, or a ceramic grace substrate is disposed with respect to the opening 65. 250 is configured.
  • the magnetoresistive element 25 is a magnetoresistive pattern for detecting a rotating magnetic field whose direction changes in the in-plane direction of the magnetic scale 9, and an A phase magnetoresistive pattern 25 (A) having a phase difference of 90 ° and a B phase.
  • the magnetic resistance pattern 25 (B) is included, and the lower end surface (each pattern surface facing the magnetic scale 9) of the A-phase magnetoresistive pattern 25 (A) and the B-phase magnetoresistive pattern 25 (B).
  • a sensor surface 250 is constructed.
  • SIN is given to the A-phase magnetoresistive pattern
  • COS is given to the B-phase magnetoresistive pattern.
  • the A-phase magnetoresistive pattern 25 (A) includes a + a-phase magnetoresistive pattern 25 (+ a) for detecting movement of the magnetic scale 9 with a phase difference of 180 °, and a -a-phase magnetoresistive pattern 25 (-a).
  • the + a phase magnetoresistive pattern 25 (+ a) is denoted by SIN +
  • the ⁇ a phase magnetoresistive pattern 25 ( ⁇ a) is denoted by SIN ⁇
  • the B phase magnetoresistive pattern 25 (B) includes a + b phase magnetoresistive pattern 25 (+ b) and a ⁇ b phase magnetoresistive pattern 25 ( ⁇ ) that detect movement of the magnetic scale 9 with a phase difference of 180 °.
  • the + b phase magnetoresistive pattern 25 (+ b) is denoted by COS +
  • the ⁇ b phase magnetoresistive pattern 25 ( ⁇ b) is denoted by COS ⁇ . is there.
  • a + a phase magnetoresistance pattern 25 (+ a), a ⁇ a phase magnetoresistance pattern 25 ( ⁇ a), a + b phase magnetoresistance pattern 25 (+ b), and a ⁇ b phase magnetoresistance pattern 25 ( ⁇ b) is formed on the same surface (main surface) of one rigid substrate 10.
  • the magnetoresistive patterns 25 (+ a), 25 ( ⁇ a), 25 (+ b), and 25 ( ⁇ b) are arranged in a lattice pattern on the rigid substrate 10, and the + a phase magnetoresistive pattern 25 (+ a) And the -a phase magnetoresistive pattern 25 (-a) are formed at diagonal positions, and the + b phase magnetoresistive pattern 25 (+ b) and the -b phase magnetoresistive pattern 25 (-b) are formed at diagonal positions. Is formed.
  • tracks 91 in which N poles and S poles are alternately arranged along the moving direction are formed.
  • three rows of tracks 91 (91A, 91B, 91C) are arranged in the width direction (magnetic sensor device). 1 and the magnetic scale 9 in the direction of relative movement).
  • the pitch of each magnetic pole is 1.0 mm or less.
  • the positions of the N pole and the S pole are shifted by one magnetic pole in the moving direction. For this reason, between the tracks 91A and 91C on both sides, the positions of the N pole and the S pole coincide with each other in the movement direction.
  • the boundary portion 912 between the adjacent track 91A and the track 91B and the boundary portion 912 between the track 91B and the track 91C are adjacent to each other without interposing a non-magnetized portion or a non-magnetic portion where no magnetic pole exists.
  • the N pole and S pole of the boundary portion 912 are formed so as to be in direct contact with each other.
  • a non-magnetized part or a non-magnetic part may be interposed.
  • FIGS. 3A, 3B, and 3C are performed.
  • a rotating magnetic field whose direction in the in-plane direction changes is formed as in the region surrounded by the circle L.
  • a strong rotating magnetic field is generated as in the region surrounded by the circle L2.
  • the boundary portion 912 between the adjacent track 91A and the track 91B and the boundary portion 912 between the track 91B and the track 91C are formed so that the N pole and the S pole of the boundary portion 912 are in direct contact with each other. Therefore, a rotating magnetic field having a higher strength is generated at the boundary portion 912 of the tracks 91A, 91B, and 91C.
  • the sensor surface 250 of the magnetic sensor device 1 is opposed to the boundary portion 912 of the tracks 91A, 91B, and 91C. Further, the sensor surface 250 is located at the center of the magnetic scale 9 in the width direction. Therefore, one end 251 in the width direction of the sensor surface 250 is located at the center in the width direction of the track 91A among the three tracks 91A, 91B, 91C, and the other end 252 is the width of the track 91C. Located in the center of the direction.
  • the region where the + a phase magnetoresistive pattern 25 (+ a) is formed and the region where the + b phase magnetoresistive pattern 25 (+ b) is formed are opposed to the boundary portion 912 of the tracks 91A and 91B.
  • the region where the -a phase magnetoresistive pattern 25 (-a) is formed and the region where the -b phase magnetoresistive pattern 25 (-b) is formed are opposite to the boundary portion 912 of the tracks 91B and 91C. is doing.
  • the track 91B includes a region where the + a-phase magnetoresistive pattern 25 (+ a) and the + b-phase magnetoresistive pattern 25 (+ b) are formed, and the -a-phase magnetoresistive pattern 25 (-a) and the -b-phase Each of the regions where the magnetoresistive pattern 25 (-b) is formed is formed at the center of the magnetic scale 9 as a track facing each other, that is, as a common track 91B.
  • FIG. 4 is an explanatory diagram of a magnetoresistive pattern formed in a magnetic sensor device of a magnetic linear encoder to which the present invention is applied.
  • FIG. 5 is an explanatory diagram showing an electrical configuration of the magnetoresistive pattern shown in FIG.
  • the main surface of the rigid substrate 10 has magnetoresistive patterns 25 (+ a), 25 ( ⁇ a), 25 (+ b), 25 ( ⁇ ) made of a magnetic film such as ferromagnetic NiFe. b) is formed as shown in FIG. 4, and these magnetoresistive patterns 25 (+ a), 25 ( ⁇ a), 25 (+ b), 25 ( ⁇ b) are shown in FIGS.
  • the magnetoresistive patterns 25 (+ a), 25 ( ⁇ a), 25 (+ b), and 25 ( ⁇ b) are formed in the central region in the longitudinal direction of the rigid substrate 10.
  • the one end portion 11 of the rigid substrate 10 is a first terminal portion 21 and the other end portion 12 is a second terminal portion 22.
  • the + a phase magnetoresistive pattern 25 (+ a) and the ⁇ a phase magnetoresistive pattern 25 ( ⁇ a) are formed at diagonal positions, and the + b phase magnetoresistive pattern 25 (+ b) and the ⁇ b phase magnetoresistive pattern.
  • 25 ( ⁇ b) is formed at a diagonal position.
  • the + a phase magnetoresistive pattern 25 (+ a) and the ⁇ a phase magnetoresistive pattern 25 ( ⁇ a) have one end at the power supply terminal 212 (Vcc), 222 (Vcc), and the other end is connected to ground terminals 213 (GND) and 223 (GND) as a first common terminal and a second common terminal.
  • the terminal 211 (+ a) for the output SIN + is connected to the midpoint position of the + a phase magnetoresistive pattern 25 (+ a), and the midpoint position of the ⁇ a phase magnetoresistive pattern 25 ( ⁇ a) is A terminal 221 (-a) for the output SIN- is connected. Therefore, if the output SIN + and the output SIN ⁇ are input to the subtracter, the differential output (sine wave signal sin) shown in FIG. 5C can be obtained.
  • the + b phase magnetoresistive pattern 25 (+ b) and the ⁇ b phase magnetoresistive pattern 25 ( ⁇ b) have one end at the power supply terminal 224 (Vcc). , 214 (Vcc).
  • the other end of the -b phase magnetoresistive pattern 25 (-b) is connected to the ground terminal 213 (GND) as the first common terminal, similarly to the + a phase magnetoresistive pattern 25 (+ a), and + b
  • the other end of the phase magnetoresistive pattern 25 (+ b) is connected to a ground terminal 223 (GND) as a second common terminal, similarly to the -a phase magnetoresistive pattern 25 (-a).
  • the terminal 225 (+ b) for the output COS + is connected to the midpoint position of the + b phase magnetoresistive pattern 25 (+ b), and the midpoint position of the ⁇ b phase magnetoresistive pattern 25 ( ⁇ b) is A terminal 215 (-b) for the output COS- is connected. Therefore, if the output COS + and the output COS ⁇ are input to the subtracter, the differential output (sine wave signal cos) shown in FIG. 5C can be obtained.
  • a dummy terminal is formed in addition to the above terminals.
  • dummy terminals are also formed in the second terminal portion 22.
  • a Z-phase magnetoresistive pattern 25 (Z) for detecting the origin position is formed in a central region in the longitudinal direction of the rigid substrate 10 in an area adjacent to the magnetoresistive pattern, and the second terminal In the portion 22, a power supply terminal 226 (Vcc), a ground terminal 227 (GND), output terminals 228 (Z), and 229 (Z) for the Z-phase magnetoresistive pattern 25 (Z) are also formed.
  • the magnetoresistive patterns 25 (+ a), 25 ( ⁇ a), 25 (+ b), and 25 ( ⁇ b) detect a rotating magnetic field with a magnetic field strength equal to or higher than the saturation sensitivity region of the resistance value. That is, at the boundary portion 912 of the adjacent track 91, the magnetic field intensity is greater than the saturation sensitivity region of the resistance value of each magnetoresistive pattern 25 (+ a), 25 ( ⁇ a), 25 (+ b), 25 ( ⁇ b).
  • a rotating magnetic field is generated in which the in-plane direction gradually changes in the circumferential direction.
  • the saturation sensitivity region generally refers to a region other than the region in which the resistance value change amount k can be approximately expressed by the magnetic field strength H and the expression “k ⁇ H2”.
  • the principle of detecting the direction of the rotating magnetic field (rotation of the magnetic vector) with a magnetic field strength equal to or higher than the saturation sensitivity region is based on magnetoresistive patterns 25 (+ a), 25 ( ⁇ a), 25 (+ b) made of ferromagnetic metal.
  • the magnetic linear encoder 100 is an open type linear encoder.
  • the magnetic sensor device 1 and the magnetic scale 9 are independently a fixed body and a movable body. Mounted on. For this reason, the magnetic sensor device 1 and the magnetic scale 9 relatively move in a non-contact state. Further, the distance between the magnetoresistive element 25 and the permanent magnet 96 shown in FIG. 2 is 0.15 mm to 0.35 mm.
  • the magnetic scale 9 has the following configuration.
  • the magnetic scale 9 has a metal base plate 95 and a permanent magnet 96 provided on one surface 950 of the base plate 95 on the magnetic sensor device 1 side. Further, the surface 960 of the permanent magnet 96 on the magnetic sensor device 1 side is exposed and is not covered with a protective sheet or the like.
  • the permanent magnet 96 is made of a magnetic coating film 97 formed on one surface 950 of the base plate 95 including magnetic powder and resin.
  • the resin is made of an epoxy resin.
  • the magnetic powder is a ferrite-based magnetic powder.
  • the permanent magnet 96 contains strontium ferrite and barium ferrite as ferrite-based magnetic powder.
  • the permanent magnet 96 contains strontium ferrite and barium ferrite in a weight ratio of 80% to 90%: 20% to 10% as ferrite magnetic powder, and the ratio of the ferrite magnetic powder in the permanent magnet 96 Is about 70% by weight.
  • the permanent magnet 96 is vertically oriented. That is, the magnetic powder contained in the magnetic coating 97 has the easy axis of magnetization in the direction perpendicular to the one surface 950 of the base plate 95 (the film thickness direction of the magnetic coating 97). More specifically, since strontium ferrite and barium ferrite are made of hexagonal plate powder, the hexagonal plates are stacked so as to be laminated. Such a configuration can be realized by applying an external magnetic field during the formation of the magnetic coating film 97 and aligning the easy magnetization axes of the magnet powder. Therefore, the permanent magnet 96 is configured as an anisotropic magnet and generates a magnetic force stronger than that of the isotropic magnet.
  • the permanent magnet 96 (magnetic coating film 97) has a thickness of 400 ⁇ m to 500 ⁇ m, and the base plate 95 is made of a nonmagnetic metal such as aluminum or an aluminum alloy.
  • the magnetic scale 9 having such a structure is formed by applying a coating liquid containing magnetic powder, resin, and solvent to the one surface 950 of the base plate 95 by spraying or the like about 100 ⁇ m, and then removing the solvent by blowing air, pre-drying, etc. After applying an external magnetic field in the state to orient the magnetic powder, the resin is temporarily cured. Then, the above process is repeated to form the magnetic coating film 97 with a predetermined thickness.
  • the magnetic coating film 97 is polished.
  • the ten-point average roughness Rzjis is set to 5 ⁇ m or less by polishing. “10-point average roughness Rzjis” is obtained by extracting only the reference length from the roughness curve in the direction of the average line and measuring in the direction of the vertical magnification from the average line of the extracted portion. Then, the sum of the average absolute value of the elevation from the highest peak to the fifth and the average absolute value of the elevation from the lowest valley to the fifth is obtained, and this value is calculated in micrometers ( ⁇ m).
  • a magnetic field is applied to the magnetic coating film 97 from a ring head (bipolar head) to magnetize the magnetic coating film 97 to obtain a permanent magnet 96.
  • FIG. 6 is a graph showing the flatness of the permanent magnet 96.
  • the flatness of the permanent magnet 96 (magnetic coating film 97) of this embodiment is shown by a solid line.
  • the flatness of a rubber magnet is shown. Is indicated by a dotted line.
  • the flatness shown in FIG. 6 is a numerical value expressing the distance of the space between planes when the upper and lower sides of the symmetrical surface are sandwiched between parallel planes in units of ⁇ m.
  • FIG. 7 is a graph showing the magnetization accuracy of the permanent magnet 96
  • FIG. 7A shows the magnetization accuracy of a rubber magnet as a comparative example
  • FIG. 7B shows the permanent accuracy of this embodiment.
  • the magnetization accuracy of the magnet 96 (magnetic coating film 97) is shown.
  • FIG. 8 is a graph showing the interpolation accuracy (resolution) of the magnet type linear encoder.
  • 8A, 8B, and 8C the permanent magnet 96 (magnetic coating film 97) of this embodiment is used in the magnetic linear encoder 100, and the distance (gap) between the magnetoresistive element 25 and the permanent magnet 96 is shown.
  • 8D, 8E, and 8F as a comparative example, a rubber magnet is used for the magnetic linear encoder 100, and a gap (gap) between the magnetoresistive element 25 and the permanent magnet 96 is 0.15 mm.
  • FIG. 9 is a graph showing the relationship between the thickness of the permanent magnet 96 (magnetic coating film 97) and the characteristics of the magnetic linear encoder 100.
  • FIGS. 9 (a), (b), and (c) The insertion accuracy, hysteresis error, and surface magnetic flux density are shown.
  • FIG. 10 is a graph showing the effect of orientation magnetization in the permanent magnet 96 (magnetic coating film 97). 10 (a) and 10 (b), when the magnetic coating film 97 is horizontally oriented, when the magnetic coating film 97 is vertically oriented, when the magnetic coating film 97 is not oriented, the rubber magnet The interpolation accuracy and the hysteresis error when vertical alignment is performed are shown.
  • * 1, * 2, and * 3 are given when the gaps (gap) between the magnetoresistive element 25 and the permanent magnet 96 are set to 0.15 mm, 0.25 mm, and 0.35 mm, respectively. This is shown in a bar graph.
  • FIG. 11 is a graph showing the influence of the material of the base plate 95 of the magnetic scale 9.
  • the base plate 95 is made of aluminum (Al / nonmagnetic)
  • the base plate 95 is made of an aluminum / iron laminated alloy (Al / nonmagnetic / Fe / magnetic).
  • the analog amplitude, the interpolation accuracy, and the hysteresis error when the base plate 95 is made of iron (Fe / magnetic) are shown.
  • the permanent magnet 96 (magnetic coating film 97) has high flatness, whereas the rubber magnet has low flatness. That is, since the surface of the permanent magnet 96 (magnetic coating film 97) is effectively polished on the rubber magnet, the surface roughness is small and the undulation is small. For this reason, as shown in FIG. 7B, the permanent magnet 96 (magnetic coating film 97) has high magnetization accuracy, whereas the rubber magnet has low magnetization accuracy. Therefore, as shown in FIG. 8, the permanent magnet 96 (magnetic coating film 97) has a stable interpolation accuracy, whereas the rubber magnet has a low stability of the interpolation accuracy.
  • the interpolation accuracy is 1.50 ⁇ m
  • the interpolation accuracy is 1.70 ⁇ m, 1.60 ⁇ m, and 2.10 ⁇ m.
  • the hysteresis error is 0.60 ⁇ m, 0. In contrast to the .60 ⁇ m and 1.00 ⁇ m, the hysteresis error of the rubber magnet is 0 when the gap (gap) between the magnetoresistive element 25 and the permanent magnet 96 is 0.15 mm, 0.25 mm, and 0.35 mm. .50 ⁇ m, 0.60 ⁇ m, and 0.70 ⁇ m.
  • the interpolation accuracy is higher in the case of 400 ⁇ m or 500 ⁇ m than in the case of 300 ⁇ m or 600 ⁇ m.
  • the reason is that when magnetizing the permanent magnet 96 (magnetic coating film 97), if 400 ⁇ m or 500 ⁇ m, the magnetization is properly performed, whereas at 300 ⁇ m, the magnetic coating film 97 is thin and necessary. This is probably because the magnetic flux density cannot be obtained. Further, at 600 ⁇ m, it is considered that the magnetic coating film 97 is thick and cannot be sufficiently magnetized.
  • the accuracy of interpolation is excellent as compared with the case where the magnetic coating film 97 is horizontally aligned or not aligned.
  • the magnetic coating film 97 is vertically oriented, sufficient interpolation accuracy is obtained when the gap (gap) between the magnetoresistive element 25 and the permanent magnet 96 is set to 0.15 mm, 0.25 mm, and 0.35 mm. be able to.
  • the gap (gap) between the magnetoresistive element 25 and the permanent magnet 96 is 0.15 mm or 0.25 mm, the interpolation accuracy is excellent as compared with the case where it is set to 0.35 mm.
  • the thickness of the permanent magnet 96 is compared when a nonmagnetic metal such as aluminum or aluminum alloy is used compared to when a magnetic metal is used. Even in the case of a thin film, sufficient analog amplitude and interpolation accuracy can be obtained. The reason is considered to be that even when the magnetic coating film 97 is relatively thin, the influence of the base plate 95 is hardly exerted during magnetization.
  • the permanent magnet 96 used for the magnetic scale 9 is composed of the magnetic coating film 97 containing magnetic powder and resin, so that it is higher than a rubber magnet. Flatness can be obtained.
  • the metal base plate 95 since the metal base plate 95 is used, it is easy to obtain high flatness in the permanent magnet 96. Therefore, since the magnetization accuracy of the magnetic scale 9 with respect to the permanent magnet 96 can be improved, the resolution and the like of the magnetic linear encoder 100 can be improved.
  • the thickness of the magnetic coating film 97 is 400 ⁇ m to 500 ⁇ m, it can be magnetized to a sufficient depth. Therefore, the resolution can be improved and the hysteresis error can be reduced.
  • the base plate 95 is made of a non-magnetic metal, the influence of the base plate 95 hardly occurs even when the base plate 95 is magnetized by the ring gate.
  • the permanent magnet 96 is vertically oriented, it is possible to improve the resolution and reduce the hysteresis error.
  • the magnetic powder used for the magnetic coating film 97 is a ferrite-based magnetic powder, the resolution can be improved when the position and the like are obtained by interpolation.
  • the surface of the permanent magnet 96 on the side of the magnetic sensor device 1 is in an exposed state, a wide interval between the magnetic sensor device 1 and the magnetic scale 9 can be secured. Therefore, it is suitable for the case where the magnetic sensor device 1 and the magnetic scale 9 are relatively moved in a non-contact state like the open type magnetic linear encoder 100.
  • the distance between the magnetoresistive element 25 and the permanent magnet 96 is 0.15 mm to 0.35 mm, it is suitable for the relative movement of the magnetic sensor device 1 and the magnetic scale 9 in a non-contact state, The resolution can be improved.
  • the thickness of the magnetic coating film 97 is 400 ⁇ m to 500 ⁇ m, and the magnetic coating Since the film 97 is vertically aligned, a sufficient magnetic field can be generated. Therefore, sufficient sensitivity and resolution can be obtained even when the magnetic sensor device 1 and the magnetic scale 9 move relative to each other in a non-contact state like the open type magnetic linear encoder 100.
  • ferrite magnetic powder is used as the magnetic powder in correspondence with the configuration in which the pitch of the magnetic pole is 1.0 mm or less.
  • pitch of the magnetic pole exceeds 1.0 mm
  • neodymium is used as the magnetic powder.
  • a high magnetic force magnetic powder such as a magnetic powder, a samarium magnetic powder, or a metal may be used.
  • the present invention is applied to the magnetic linear encoder 100 that detects the direction of the rotating magnetic field with a magnetic field strength equal to or higher than the saturation sensitivity region in the magnetic sensor device 1.
  • the present invention may be applied to the linear encoder 100 and the magnetic linear encoder 100 of a type that detects the direction of the rotating magnetic field with the magnetic field strength in a region other than the saturation sensitivity region.
  • the base plate 95 is made of a nonmagnetic material, but a base plate 95 made of a magnetic material may be used. Moreover, the structure in which the protective layer is formed in the surface 960 of the permanent magnet 96 may be sufficient.
  • the number of tracks 91 is three. However, the present invention may be applied when the number of tracks 91 is one, two, three, or more.
  • the permanent magnet 96 is vertically oriented. However, the present invention may be applied to a case where the permanent magnet 96 is horizontally oriented.
  • the resin of the permanent magnet 96 (magnetic coating film 97) is an epoxy resin, but the resin may be a polyurethane resin, a phenol resin, an acrylic resin, a vinyl resin, a polyester resin, or the like.

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Abstract

The present invention provides a magnetic linear encoder capable of enhancing the magnetization accuracy of a permanent magnet of a magnetic scale. More specifically, a magnetic linear encoder 100 has a magnetic scale 9 provided with a permanent magnet 96, and a magnetic sensor device 1 for detecting the magnetic field from the magnetic scale 9, and the magnetic sensor device 1 and magnetic scale 9 move relative to each other in a state of not being in contact with each other. The permanent magnet 96 comprises a magnetic coating layer 97 that includes magnetic powder and resin and is formed on one surface of a metallic base plate 95. The magnetic powder used in the permanent magnet 96 is a vertically oriented ferritic magnetic powder. The surface 960 of the permanent magnet 96 on the side of the magnetic sensor device 1 is in an exposed state.

Description

磁気式リニアエンコーダMagnetic linear encoder
　本発明は、磁気スケールからの磁界を磁気センサ装置によって検出する磁気式リニアエンコーダに関するものである。 The present invention relates to a magnetic linear encoder that detects a magnetic field from a magnetic scale by a magnetic sensor device.
　磁気式リニアエンコーダは、永久磁石を備えた磁気スケールと、磁気抵抗素子を備えた磁気センサ装置とを有しており、磁気スケールと磁気センサ装置とが相対移動した際の磁気センサ装置での検出結果に基づいて、磁気スケールと磁気センサ装置との相対位置等を検出する。ここで、磁気スケールは、例えば、ベース板に対して永久磁石と保護シートとが積層された構造を有している（特許文献１参照）。 The magnetic linear encoder has a magnetic scale having a permanent magnet and a magnetic sensor device having a magnetoresistive element, and detection by the magnetic sensor device when the magnetic scale and the magnetic sensor device move relative to each other. Based on the result, the relative position between the magnetic scale and the magnetic sensor device is detected. Here, the magnetic scale has, for example, a structure in which a permanent magnet and a protective sheet are laminated on a base plate (see Patent Document 1).
　かかる磁気式リニアエンコーダにおいて、永久磁石としては、ゴムに磁性粉を混合したゴムマグネットが使用される場合が多い。 In such a magnetic linear encoder, a rubber magnet in which magnetic powder is mixed with rubber is often used as a permanent magnet.
特開２００７－２７１６０８号公報JP 2007-271608 A
　上記特許文献１に記載の磁気式リニアエンコーダにおいて、感度や分解能を高めるには、永久磁石に対する着磁精度が高いことが求められるが、ゴムマグネット（永久磁石）の表面は、平面度が低いため、着磁精度が低いという問題点がある。 In the magnetic linear encoder described in Patent Document 1, in order to increase sensitivity and resolution, it is required that the magnetization accuracy of the permanent magnet is high, but the surface of the rubber magnet (permanent magnet) has low flatness. There is a problem that the magnetization accuracy is low.
　以上の問題点に鑑みて、本発明の課題は、磁気スケールの永久磁石における着磁精度を向上することのできる磁気式リニアエンコーダを提供することにある。 In view of the above problems, an object of the present invention is to provide a magnetic linear encoder capable of improving the magnetization accuracy of a permanent magnet of a magnetic scale.
　上記課題を解決するために、本発明に係る磁気式リニアエンコーダは、永久磁石を備えた磁気スケールと、該磁気スケールからの磁界を検出する磁気抵抗素子を備えた磁気センサ装置と、を有し、前記永久磁石には、前記磁気センサ装置と前記磁気スケールとの相対移動方向に沿ってＮ極とＳ極とが交互に並ぶトラックが形成されている磁気式リニアエンコーダにおいて、前記永久磁石は、磁性粉と樹脂とを含んで金属製のベース板の一方側の面に形成された磁性塗膜からなることを特徴とする。 In order to solve the above problems, a magnetic linear encoder according to the present invention includes a magnetic scale including a permanent magnet and a magnetic sensor device including a magnetoresistive element that detects a magnetic field from the magnetic scale. In the magnetic linear encoder in which the permanent magnet is formed with tracks in which N poles and S poles are alternately arranged along the relative movement direction of the magnetic sensor device and the magnetic scale, It consists of a magnetic coating film formed on one surface of a metal base plate containing magnetic powder and resin.
　本発明において、磁気スケールに用いた永久磁石は、磁性粉と樹脂とを含む磁性塗膜からなるため、ゴムマグネットに比して、加工性良く高い平面度を得ることができる。また、本形態では、金属製のベース板を用いているため、永久磁石に高い平面度を得やすい。従って、磁気スケールの永久磁石に対する着磁精度を向上することができるので、磁気式リニアエンコーダの分解能等を向上することができる。 In the present invention, since the permanent magnet used for the magnetic scale is made of a magnetic coating film containing magnetic powder and resin, it is possible to obtain high flatness with good workability as compared with a rubber magnet. In this embodiment, since a metal base plate is used, it is easy to obtain high flatness in the permanent magnet. Therefore, since the magnetization accuracy of the permanent magnet of the magnetic scale can be improved, the resolution and the like of the magnetic linear encoder can be improved.
　本発明において、前記磁性塗膜の厚さは、４００μｍから５００μｍであることが好ましい。かかる構成によれば、磁性塗膜に適正な着磁を行うことができるので、分解能の向上やヒステリシス誤差の低減を図ることができる。 In the present invention, the thickness of the magnetic coating film is preferably 400 μm to 500 μm. According to such a configuration, it is possible to appropriately magnetize the magnetic coating film, so that the resolution can be improved and the hysteresis error can be reduced.
　本発明において、前記ベース板は、非磁性の金属製であることが好ましい。かかる構成によれば、リングゲートによって着磁を行っても、ベース板の影響が発生しにくい。 In the present invention, the base plate is preferably made of a nonmagnetic metal. According to such a configuration, even if magnetization is performed by the ring gate, the influence of the base plate is hardly generated.
　本発明において、前記永久磁石は、前記磁性粉の磁化容易軸が前記磁性塗膜の膜厚方向に向いていることが好ましい。かかる構成によれば、分解能の向上やヒステリシス誤差の低減を図ることができる。 In the present invention, the permanent magnet preferably has an easy axis of magnetization of the magnetic powder oriented in a film thickness direction of the magnetic coating film. According to this configuration, it is possible to improve the resolution and reduce the hysteresis error.
　本発明において、前記磁性粉は、フェライト系磁性粉であることが好ましい。かかる構成によれば、内挿によって位置等を求めた際、分解能の向上を図ることができる。 In the present invention, the magnetic powder is preferably ferrite magnetic powder. According to such a configuration, it is possible to improve the resolution when the position or the like is obtained by interpolation.
　本発明において、前記永久磁石は、前記フェライト系磁性粉として、ストロンチウムフェライトと、バリウムフェライトと、を含んでいることが好ましい。 In the present invention, the permanent magnet preferably contains strontium ferrite and barium ferrite as the ferrite-based magnetic powder.
　本発明は、前記磁気センサ装置と前記磁気スケールとが非接触状態で相対移動するオープンタイプの磁気式リニアエンコーダに適用すると効果的である。 The present invention is effective when applied to an open type magnetic linear encoder in which the magnetic sensor device and the magnetic scale are relatively moved in a non-contact state.
　本発明において、前記永久磁石は、前記磁気センサ装置側の面が露出状態にあることが好ましい。かかる構成によれば、磁気センサ装置と磁気スケールとの間隔を広く確保することができるので、永久磁石と磁気センサ装置との接触が発生しにくい。 In the present invention, the permanent magnet preferably has an exposed surface on the magnetic sensor device side. According to such a configuration, it is possible to ensure a wide interval between the magnetic sensor device and the magnetic scale, so that contact between the permanent magnet and the magnetic sensor device hardly occurs.
　本発明において、前記磁気抵抗素子と前記永久磁石との間隔が０．１５ｍｍから０．３５ｍｍであることが好ましい。かかる構成によれば、磁気センサ装置と磁気スケールとの間隔を広く確保でき、その場合でも、十分な分解能を得ることができる。 In the present invention, it is preferable that a distance between the magnetoresistive element and the permanent magnet is 0.15 mm to 0.35 mm. According to this configuration, a wide interval between the magnetic sensor device and the magnetic scale can be secured, and even in that case, sufficient resolution can be obtained.
　本発明では、前記磁気スケールにおいて、前記トラックは、前記相対移動方向と交差する方向に複数列、設けられ、前記複数列のトラックにおいて、隣り合う２つのトラックでは、前記相対移動方向においてＮ極とＳ極とがずれていることが好ましい。かかる構成によれば、トラックの幅方向における縁部分のうち、トラックの境界部分では、強度の大きな回転磁界が発生する。従って、かかるトラックの境界部分に対して磁気センサ装置のセンサ面を面対向させれば、磁気式リニアエンコーダの検出精度を向上することができる。 In the present invention, in the magnetic scale, the tracks are provided in a plurality of rows in a direction intersecting the relative movement direction, and two adjacent tracks in the plurality of rows have N poles in the relative movement direction. It is preferable that the S pole is deviated. According to such a configuration, a strong rotating magnetic field is generated at the track boundary portion of the edge portion in the track width direction. Therefore, the detection accuracy of the magnetic linear encoder can be improved by making the sensor surface of the magnetic sensor device face the boundary portion of the track.
　本発明において、前記磁気抵抗素子は、前記永久磁石の回転磁界を検出する構成を採用することができる。かかる構成によれば、磁気スケールと磁気センサ装置との隙間寸法が狭い場合でも、正弦波成分を安定して得ることができる。 In the present invention, the magnetoresistive element can employ a configuration for detecting a rotating magnetic field of the permanent magnet. According to such a configuration, a sine wave component can be stably obtained even when the gap between the magnetic scale and the magnetic sensor device is narrow.
　本発明において、磁気スケールに用いた永久磁石は、磁性粉と樹脂とを含む磁性塗膜からなるため、ゴムマグネットに比して、高い平面度を得ることができる。また、本形態では、金属製のベース板を用いているため、永久磁石に高い平面度を得やすい。従って、磁気スケールの永久磁石に対する着磁精度を向上することができるので、磁気式リニアエンコーダの分解能等を向上することができる。 In the present invention, since the permanent magnet used for the magnetic scale is made of a magnetic coating film containing magnetic powder and resin, a higher flatness can be obtained compared to a rubber magnet. In this embodiment, since a metal base plate is used, it is easy to obtain high flatness in the permanent magnet. Therefore, since the magnetization accuracy of the permanent magnet of the magnetic scale can be improved, the resolution and the like of the magnetic linear encoder can be improved.
本発明を適用した磁気式リニアエンコーダの外観等を示す説明図である。It is explanatory drawing which shows the external appearance etc. of the magnetic type linear encoder to which this invention is applied. 本発明を適用した磁気式リニアエンコーダの要部を示す説明図である。It is explanatory drawing which shows the principal part of the magnetic type linear encoder to which this invention is applied. 本発明を適用した磁気式リニアエンコーダの磁気スケールの磁気的特性を示す説明図である。It is explanatory drawing which shows the magnetic characteristic of the magnetic scale of the magnetic type linear encoder to which this invention is applied. 本発明を適用した磁気式リニアエンコーダの磁気センサ装置に形成した磁気抵抗パターンの説明図である。It is explanatory drawing of the magnetoresistive pattern formed in the magnetic sensor apparatus of the magnetic type linear encoder to which this invention is applied. 図４に示す磁気抵抗パターンの電気的な構成を示す説明図である。It is explanatory drawing which shows the electrical structure of the magnetoresistive pattern shown in FIG. 永久磁石の平面度を示すグラフである。It is a graph which shows the flatness of a permanent magnet. 永久磁石の着磁精度を示すグラフである。It is a graph which shows the magnetization accuracy of a permanent magnet. 磁気型リニアエンコーダの内挿精度（分解能）を示すグラフである。It is a graph which shows the interpolation precision (resolution) of a magnetic type linear encoder. 永久磁石（磁性塗膜）の厚さと、磁気式リニアエンコーダの特性との関係を示すグラフである。It is a graph which shows the relationship between the thickness of a permanent magnet (magnetic coating film), and the characteristic of a magnetic type linear encoder. 永久磁石（磁性塗膜）における配向着磁の効果を示すグラフである。It is a graph which shows the effect of orientation magnetization in a permanent magnet (magnetic coating film). 磁気スケールのベース板の材質の影響を示すグラフである。It is a graph which shows the influence of the material of the base plate of a magnetic scale.
　図面を参照して、本発明を実施するため形態を説明する。 Embodiments for carrying out the present invention will be described with reference to the drawings.
　（全体構成）
　図１は、本発明を適用した磁気式リニアエンコーダの外観等を示す説明図である。図２は、本発明を適用した磁気式リニアエンコーダの要部を示す説明図であり、図２（ａ）、（ｂ）、（ｃ）は、磁気センサ装置の要部の構成を示す概略断面図、その概略斜視図、および概略平面図である。図３は、本発明を適用した磁気式リニアエンコーダの磁気スケールの磁気的特性を示す説明図であり、図３（ａ）、（ｂ）、（ｃ）は、磁界の向きを平面的にみたときの説明図、斜めにみたときの説明図、および側方からみたときの説明図である。 (overall structure)
FIG. 1 is an explanatory diagram showing the appearance and the like of a magnetic linear encoder to which the present invention is applied. FIG. 2 is an explanatory view showing a main part of a magnetic linear encoder to which the present invention is applied. FIGS. 2A, 2B, and 2C are schematic cross sections showing the structure of the main part of the magnetic sensor device. It is a figure, its schematic perspective view, and a schematic plan view. FIG. 3 is an explanatory diagram showing the magnetic characteristics of the magnetic scale of the magnetic linear encoder to which the present invention is applied. FIGS. 3A, 3B, and 3C show the direction of the magnetic field in a plan view. It is explanatory drawing at the time, explanatory drawing when it sees diagonally, and explanatory drawing when it sees from the side.
　図１に示すように、磁気式リニアエンコーダ１００は、一方方向に延在する磁気スケール９と、磁気スケール９の近傍に配置された磁気センサ装置１とを有している。かかる磁気式リニアエンコーダ１００においては、磁気スケール９および磁気センサ装置１の一方が固定体に保持され、他方が移動体に保持される。本形態では、例えば、磁気センサ装置１が固定体に保持され、磁気スケール９が移動体に保持される。 As shown in FIG. 1, the magnetic linear encoder 100 has a magnetic scale 9 extending in one direction and a magnetic sensor device 1 arranged in the vicinity of the magnetic scale 9. In the magnetic linear encoder 100, one of the magnetic scale 9 and the magnetic sensor device 1 is held by a fixed body, and the other is held by a moving body. In this embodiment, for example, the magnetic sensor device 1 is held by a fixed body, and the magnetic scale 9 is held by a moving body.
　磁気スケール９には、後述するように、長手方向（磁気センサ装置１と磁気スケール９との相対移動方向）に沿ってＮ極とＳ極とが交互に配列されたトラックが形成されており、磁気センサ装置１は、磁気スケール９の表面に形成された回転磁界の方向を検出することにより、磁気スケール９（移動体）が磁気スケール９の長手方向に移動した際の位置等を検出する。 As will be described later, the magnetic scale 9 is formed with tracks in which N poles and S poles are alternately arranged along the longitudinal direction (the relative movement direction of the magnetic sensor device 1 and the magnetic scale 9). The magnetic sensor device 1 detects the position or the like when the magnetic scale 9 (moving body) moves in the longitudinal direction of the magnetic scale 9 by detecting the direction of the rotating magnetic field formed on the surface of the magnetic scale 9.
　磁気センサ装置１は、略直方体形状のアルミニウムダイカスト品からなるホルダ６と、このホルダ６の開口を覆う矩形のカバー６８と、ホルダ６から延びたケーブル７とを備えている。ホルダ６にはその側面にケーブル挿通穴６９が形成されており、このケーブル挿通穴６９からケーブル７が引き出されている。 The magnetic sensor device 1 includes a holder 6 made of a substantially rectangular parallelepiped aluminum die-cast product, a rectangular cover 68 covering the opening of the holder 6, and a cable 7 extending from the holder 6. A cable insertion hole 69 is formed on the side surface of the holder 6, and the cable 7 is drawn from the cable insertion hole 69.
　図２（ａ）、（ｂ）、（ｃ）に示すように、ホルダ６には、磁気スケール９と対向する底面に、段差を介してホルダ６の底面から突出した平坦面からなる基準面６０が形成されている。基準面６０には開口部６５が形成されており、開口部６５に対して、ガラス基板やシリコン基板、セラミックグレース基板などの剛性基板１０上に形成された磁気抵抗素子２５が配置され、センサ面２５０が構成されている。 As shown in FIGS. 2A, 2B, and 2C, the holder 6 has a reference surface 60 made of a flat surface protruding from the bottom surface of the holder 6 through a step on the bottom surface facing the magnetic scale 9. Is formed. An opening 65 is formed in the reference surface 60, and the magnetoresistive element 25 formed on the rigid substrate 10 such as a glass substrate, a silicon substrate, or a ceramic grace substrate is disposed with respect to the opening 65. 250 is configured.
　磁気抵抗素子２５は、磁気スケール９の面内方向で向きが変化する回転磁界を検出する磁気抵抗パターンとして、互いに９０°の位相差を有するＡ相の磁気抵抗パターン２５（Ａ）とＢ相の磁気抵抗パターン２５（Ｂ）とを有しており、Ａ相の磁気抵抗パターン２５（Ａ）とＢ相の磁気抵抗パターン２５（Ｂ）の下端面（磁気スケール９と対向する各パターン面）によってセンサ面２５０が構成されている。なお、図２には、Ａ相の磁気抵抗パターンにはＳＩＮを付し、Ｂ相の磁気抵抗パターンには、ＣＯＳを付してある。 The magnetoresistive element 25 is a magnetoresistive pattern for detecting a rotating magnetic field whose direction changes in the in-plane direction of the magnetic scale 9, and an A phase magnetoresistive pattern 25 (A) having a phase difference of 90 ° and a B phase. The magnetic resistance pattern 25 (B) is included, and the lower end surface (each pattern surface facing the magnetic scale 9) of the A-phase magnetoresistive pattern 25 (A) and the B-phase magnetoresistive pattern 25 (B). A sensor surface 250 is constructed. In FIG. 2, SIN is given to the A-phase magnetoresistive pattern, and COS is given to the B-phase magnetoresistive pattern.
　Ａ相の磁気抵抗パターン２５（Ａ）は、１８０°の位相差をもって磁気スケール９の移動検出を行う＋ａ相の磁気抵抗パターン２５（＋ａ）と－ａ相の磁気抵抗パターン２５（－ａ）とを備えており、図面には、＋ａ相の磁気抵抗パターン２５（＋ａ）にはＳＩＮ＋と付し、－ａ相の磁気抵抗パターン２５（－ａ）には、ＳＩＮ－を付してある。同様に、Ｂ相の磁気抵抗パターン２５（Ｂ）は、１８０°の位相差をもって磁気スケール９の移動検出を行う＋ｂ相の磁気抵抗パターン２５（＋ｂ）と－ｂ相の磁気抵抗パターン２５（－ｂ）とを備えており、図面には、＋ｂ相の磁気抵抗パターン２５（＋ｂ）にはＣＯＳ＋と付し、－ｂ相の磁気抵抗パターン２５（－ｂ）には、ＣＯＳ－を付してある。 The A-phase magnetoresistive pattern 25 (A) includes a + a-phase magnetoresistive pattern 25 (+ a) for detecting movement of the magnetic scale 9 with a phase difference of 180 °, and a -a-phase magnetoresistive pattern 25 (-a). In the drawing, the + a phase magnetoresistive pattern 25 (+ a) is denoted by SIN +, and the −a phase magnetoresistive pattern 25 (−a) is denoted by SIN−. Similarly, the B phase magnetoresistive pattern 25 (B) includes a + b phase magnetoresistive pattern 25 (+ b) and a −b phase magnetoresistive pattern 25 (−) that detect movement of the magnetic scale 9 with a phase difference of 180 °. In the drawing, the + b phase magnetoresistive pattern 25 (+ b) is denoted by COS +, and the −b phase magnetoresistive pattern 25 (−b) is denoted by COS−. is there.
　本形態では、＋ａ相の磁気抵抗パターン２５（＋ａ）、－ａ相の磁気抵抗パターン２５（－ａ）、＋ｂ相の磁気抵抗パターン２５（＋ｂ）、および－ｂ相の磁気抵抗パターン２５（－ｂ）は、１枚の剛性基板１０の同一の面上（主面上）に形成されている。また、磁気抵抗パターン２５（＋ａ）、２５（－ａ）、２５（＋ｂ）、２５（－ｂ）は、剛性基板１０で格子状に配置されており、＋ａ相の磁気抵抗パターン２５（＋ａ）と－ａ相の磁気抵抗パターン２５（－ａ）とは対角位置に形成され、＋ｂ相の磁気抵抗パターン２５（＋ｂ）と－ｂ相の磁気抵抗パターン２５（－ｂ）とは対角位置に形成されている。 In this embodiment, a + a phase magnetoresistance pattern 25 (+ a), a −a phase magnetoresistance pattern 25 (−a), a + b phase magnetoresistance pattern 25 (+ b), and a −b phase magnetoresistance pattern 25 (− b) is formed on the same surface (main surface) of one rigid substrate 10. The magnetoresistive patterns 25 (+ a), 25 (−a), 25 (+ b), and 25 (−b) are arranged in a lattice pattern on the rigid substrate 10, and the + a phase magnetoresistive pattern 25 (+ a) And the -a phase magnetoresistive pattern 25 (-a) are formed at diagonal positions, and the + b phase magnetoresistive pattern 25 (+ b) and the -b phase magnetoresistive pattern 25 (-b) are formed at diagonal positions. Is formed.
　磁気スケール９では、移動方向に沿ってＮ極とＳ極が交互に並ぶトラック９１が形成されており、本形態では、３列のトラック９１（９１Ａ、９１Ｂ、９１Ｃ）が幅方向（磁気センサ装置１と磁気スケール９との相対移動方向に交差する方向）で並列している。本形態において、各磁極のピッチは１．０ｍｍ以下である。ここで、隣接するトラック９１Ａ、９１Ｂ、９１Ｃ間では、Ｎ極およびＳ極の位置が移動方向で１磁極分、ずれている。このため、両側のトラック９１Ａ、９１Ｃ間では、Ｎ極およびＳ極の位置が移動方向で一致している。ここで、隣接するトラック９１Ａとトラック９１Ｂの境界部分９１２、およびトラック９１Ｂとトラック９１Ｃの境界部分９１２は、例えば、磁極が存在しない無着磁部分や非磁性部分を介在させることなく、隣接する当該境界部分９１２のＮ極およびＳ極が直接、接するように形成されている。但し、磁気センサ装置１が検出できるような強度の大きな回転磁界を発生させることができれば、隣接するトラック９１Ａとトラック９１Ｂの境界部分９１２、およびトラック９１Ｂとトラック９１Ｃの境界部分９１２に磁極が存在しない無着磁部分や非磁性部分を介在させてあっても良い。 In the magnetic scale 9, tracks 91 in which N poles and S poles are alternately arranged along the moving direction are formed. In this embodiment, three rows of tracks 91 (91A, 91B, 91C) are arranged in the width direction (magnetic sensor device). 1 and the magnetic scale 9 in the direction of relative movement). In this embodiment, the pitch of each magnetic pole is 1.0 mm or less. Here, between the adjacent tracks 91A, 91B, 91C, the positions of the N pole and the S pole are shifted by one magnetic pole in the moving direction. For this reason, between the tracks 91A and 91C on both sides, the positions of the N pole and the S pole coincide with each other in the movement direction. Here, the boundary portion 912 between the adjacent track 91A and the track 91B and the boundary portion 912 between the track 91B and the track 91C are adjacent to each other without interposing a non-magnetized portion or a non-magnetic portion where no magnetic pole exists. The N pole and S pole of the boundary portion 912 are formed so as to be in direct contact with each other. However, if a strong rotating magnetic field that can be detected by the magnetic sensor device 1 can be generated, there is no magnetic pole in the boundary portion 912 between the adjacent track 91A and the track 91B and the boundary portion 912 between the track 91B and the track 91C. A non-magnetized part or a non-magnetic part may be interposed.
　このように構成した磁気式リニアエンコーダ１００において、磁気スケール９の磁界の面内方向の向きをマトリクス状の微小領域毎に磁場解析したところ、図３（ａ）、（ｂ）、（ｃ）に矢印で示すように、トラック９１Ａ、９１Ｂ、９１Ｃの幅方向の縁部分９１１では、円Ｌで囲んだ領域のように、面内方向の向きが変化する回転磁界が形成され、特に、トラック９１Ａ、９１Ｂ、９１Ｃの境界部分９１２では、円Ｌ２で囲んだ領域のように、強度の大きな回転磁界が発生している。さらに、本形態では、隣接するトラック９１Ａとトラック９１Ｂの境界部分９１２、およびトラック９１Ｂとトラック９１Ｃの境界部分９１２は、当該境界部分９１２のＮ極およびＳ極が直接、接するように形成されているので、トラック９１Ａ、９１Ｂ、９１Ｃの境界部分９１２では、より強度の大きな回転磁界が発生している。 In the magnetic linear encoder 100 configured as described above, when the magnetic field analysis is performed on the in-plane direction of the magnetic field of the magnetic scale 9 for each minute region in the matrix form, FIGS. 3A, 3B, and 3C are performed. As indicated by the arrows, at the edge portions 911 in the width direction of the tracks 91A, 91B, and 91C, a rotating magnetic field whose direction in the in-plane direction changes is formed as in the region surrounded by the circle L. In the boundary portion 912 between 91B and 91C, a strong rotating magnetic field is generated as in the region surrounded by the circle L2. Further, in this embodiment, the boundary portion 912 between the adjacent track 91A and the track 91B and the boundary portion 912 between the track 91B and the track 91C are formed so that the N pole and the S pole of the boundary portion 912 are in direct contact with each other. Therefore, a rotating magnetic field having a higher strength is generated at the boundary portion 912 of the tracks 91A, 91B, and 91C.
　従って、本形態では、図２（ｃ）に示すように、トラック９１Ａ、９１Ｂ、９１Ｃの境界部分９１２に対して磁気センサ装置１のセンサ面２５０を面対向させている。また、センサ面２５０は、磁気スケール９の幅方向の中央に位置している。このため、センサ面２５０の幅方向における一方の端部２５１は、３つのトラック９１Ａ、９１Ｂ、９１Ｃのうち、トラック９１Ａの幅方向の中央に位置し、他方の端部２５２は、トラック９１Ｃの幅方向の中央に位置している。従って、＋ａ相の磁気抵抗パターン２５（＋ａ）が形成されている領域、および＋ｂ相の磁気抵抗パターン２５（＋ｂ）が形成されている領域は、トラック９１Ａ、９１Ｂの境界部分９１２に対向し、－ａ相の磁気抵抗パターン２５（－ａ）が形成されている領域、および－ｂ相の磁気抵抗パターン２５（－ｂ）が形成されている領域は、トラック９１Ｂ、９１Ｃの境界部分９１２に対向している。トラック９１Ｂは、＋ａ相の磁気抵抗パターン２５（＋ａ）および＋ｂ相の磁気抵抗パターン２５（＋ｂ）が形成されている領域と、－ａ相の磁気抵抗パターン２５（－ａ）および－ｂ相の磁気抵抗パターン２５（－ｂ）が形成されている領域のそれぞれの領域が対向するトラック、すなわち、兼用する共通のトラック９１Ｂとして磁気スケール９の中央に形成されている。 Therefore, in this embodiment, as shown in FIG. 2C, the sensor surface 250 of the magnetic sensor device 1 is opposed to the boundary portion 912 of the tracks 91A, 91B, and 91C. Further, the sensor surface 250 is located at the center of the magnetic scale 9 in the width direction. Therefore, one end 251 in the width direction of the sensor surface 250 is located at the center in the width direction of the track 91A among the three tracks 91A, 91B, 91C, and the other end 252 is the width of the track 91C. Located in the center of the direction. Therefore, the region where the + a phase magnetoresistive pattern 25 (+ a) is formed and the region where the + b phase magnetoresistive pattern 25 (+ b) is formed are opposed to the boundary portion 912 of the tracks 91A and 91B. The region where the -a phase magnetoresistive pattern 25 (-a) is formed and the region where the -b phase magnetoresistive pattern 25 (-b) is formed are opposite to the boundary portion 912 of the tracks 91B and 91C. is doing. The track 91B includes a region where the + a-phase magnetoresistive pattern 25 (+ a) and the + b-phase magnetoresistive pattern 25 (+ b) are formed, and the -a-phase magnetoresistive pattern 25 (-a) and the -b-phase Each of the regions where the magnetoresistive pattern 25 (-b) is formed is formed at the center of the magnetic scale 9 as a track facing each other, that is, as a common track 91B.
　（磁気抵抗パターンの構成）
　図４は、本発明を適用した磁気式リニアエンコーダの磁気センサ装置に形成した磁気抵抗パターンの説明図である。図５は、図４に示す磁気抵抗パターンの電気的な構成を示す説明図である。 (Configuration of magnetoresistive pattern)
FIG. 4 is an explanatory diagram of a magnetoresistive pattern formed in a magnetic sensor device of a magnetic linear encoder to which the present invention is applied. FIG. 5 is an explanatory diagram showing an electrical configuration of the magnetoresistive pattern shown in FIG.
　本形態の磁気センサ装置１において、剛性基板１０の主面では、強磁性体ＮｉＦｅ等の磁性体膜からなる磁気抵抗パターン２５（＋ａ）、２５（－ａ）、２５（＋ｂ）、２５（－ｂ）が図４に示すように形成されており、これらの磁気抵抗パターン２５（＋ａ）、２５（－ａ）、２５（＋ｂ）、２５（－ｂ）は、図５（ａ）、（ｂ）に示すブリッジ回路を構成している。 In the magnetic sensor device 1 of the present embodiment, the main surface of the rigid substrate 10 has magnetoresistive patterns 25 (+ a), 25 (−a), 25 (+ b), 25 (−) made of a magnetic film such as ferromagnetic NiFe. b) is formed as shown in FIG. 4, and these magnetoresistive patterns 25 (+ a), 25 (−a), 25 (+ b), 25 (−b) are shown in FIGS. The bridge circuit shown in FIG.
　より具体的には、図４に示すように、磁気抵抗パターン２５（＋ａ）、２５（－ａ）、２５（＋ｂ）、２５（－ｂ）は、剛性基板１０の長手方向における中央領域に形成され、剛性基板１０の一方側端部１１は第１の端子部２１とされ、他方側端部１２は第２の端子部２２とされている。＋ａ相の磁気抵抗パターン２５（＋ａ）と－ａ相の磁気抵抗パターン２５（－ａ）とは対角位置に形成され、＋ｂ相の磁気抵抗パターン２５（＋ｂ）と－ｂ相の磁気抵抗パターン２５（－ｂ）とは対角位置に形成されている。 More specifically, as shown in FIG. 4, the magnetoresistive patterns 25 (+ a), 25 (−a), 25 (+ b), and 25 (−b) are formed in the central region in the longitudinal direction of the rigid substrate 10. The one end portion 11 of the rigid substrate 10 is a first terminal portion 21 and the other end portion 12 is a second terminal portion 22. The + a phase magnetoresistive pattern 25 (+ a) and the −a phase magnetoresistive pattern 25 (−a) are formed at diagonal positions, and the + b phase magnetoresistive pattern 25 (+ b) and the −b phase magnetoresistive pattern. 25 (−b) is formed at a diagonal position.
　また、図４および図５（ａ）に示すように、＋ａ相の磁気抵抗パターン２５（＋ａ）および－ａ相の磁気抵抗パターン２５（－ａ）は、一方端が電源端子２１２（Ｖｃｃ）、２２２（Ｖｃｃ）に接続され、他方端は、第１の共通端子および第２の共通端子としてのグランド端子２１３（ＧＮＤ）、２２３（ＧＮＤ）に接続されている。また、＋ａ相の磁気抵抗パターン２５（＋ａ）の中点位置には、出力ＳＩＮ＋に対する端子２１１（＋ａ）が接続し、－ａ相の磁気抵抗パターン２５（－ａ）の中点位置には、出力ＳＩＮ－に対する端子２２１（－ａ）が接続している。従って、出力ＳＩＮ＋および出力ＳＩＮ－を減算器に入力すれば、図５（ｃ）に示す差動出力（正弦波信号ｓｉｎ）を得ることができる。 As shown in FIGS. 4 and 5A, the + a phase magnetoresistive pattern 25 (+ a) and the −a phase magnetoresistive pattern 25 (−a) have one end at the power supply terminal 212 (Vcc), 222 (Vcc), and the other end is connected to ground terminals 213 (GND) and 223 (GND) as a first common terminal and a second common terminal. Further, the terminal 211 (+ a) for the output SIN + is connected to the midpoint position of the + a phase magnetoresistive pattern 25 (+ a), and the midpoint position of the −a phase magnetoresistive pattern 25 (−a) is A terminal 221 (-a) for the output SIN- is connected. Therefore, if the output SIN + and the output SIN− are input to the subtracter, the differential output (sine wave signal sin) shown in FIG. 5C can be obtained.
　同様に、図４および図５（ｂ）に示すように、＋ｂ相の磁気抵抗パターン２５（＋ｂ）および－ｂ相の磁気抵抗パターン２５（－ｂ）は、一方端が電源端子２２４（Ｖｃｃ）、２１４（Ｖｃｃ）に接続されている。また、－ｂ相の磁気抵抗パターン２５（－ｂ）の他方端は、＋ａ相の磁気抵抗パターン２５（＋ａ）と同様、第１の共通端子としてのグランド端子２１３（ＧＮＤ）に接続し、＋ｂ相の磁気抵抗パターン２５（＋ｂ）の他方端は、－ａ相の磁気抵抗パターン２５（－ａ）と同様、第２の共通端子としてのグランド端子２２３（ＧＮＤ）に接続している。さらに、＋ｂ相の磁気抵抗パターン２５（＋ｂ）の中点位置には、出力ＣＯＳ＋に対する端子２２５（＋ｂ）が接続し、－ｂ相の磁気抵抗パターン２５（－ｂ）の中点位置には、出力ＣＯＳ－に対する端子２１５（－ｂ）が接続している。従って、出力ＣＯＳ＋および出力ＣＯＳ－を減算器に入力すれば、図５（ｃ）に示す差動出力（正弦波信号ｃｏｓ）を得ることができる。 Similarly, as shown in FIGS. 4 and 5B, the + b phase magnetoresistive pattern 25 (+ b) and the −b phase magnetoresistive pattern 25 (−b) have one end at the power supply terminal 224 (Vcc). , 214 (Vcc). The other end of the -b phase magnetoresistive pattern 25 (-b) is connected to the ground terminal 213 (GND) as the first common terminal, similarly to the + a phase magnetoresistive pattern 25 (+ a), and + b The other end of the phase magnetoresistive pattern 25 (+ b) is connected to a ground terminal 223 (GND) as a second common terminal, similarly to the -a phase magnetoresistive pattern 25 (-a). Further, the terminal 225 (+ b) for the output COS + is connected to the midpoint position of the + b phase magnetoresistive pattern 25 (+ b), and the midpoint position of the −b phase magnetoresistive pattern 25 (−b) is A terminal 215 (-b) for the output COS- is connected. Therefore, if the output COS + and the output COS− are input to the subtracter, the differential output (sine wave signal cos) shown in FIG. 5C can be obtained.
　なお、第１の端子部２１には、上記の端子の他にダミーの端子が形成されている。第２の端子部２２にも、上記の端子の他に、ダミーの端子が形成されている。また、剛性基板１０の長手方向における中央領域には、上記の磁気抵抗パターンと隣接する領域に、原点位置を検出するためのＺ相の磁気抵抗パターン２５（Ｚ）が形成され、第２の端子部２２には、Ｚ相の磁気抵抗パターン２５（Ｚ）に対する電源端子２２６（Ｖｃｃ）、グランド端子２２７（ＧＮＤ）、出力端子２２８（Ｚ）、２２９（Ｚ）も形成されている。 In addition, in the first terminal portion 21, a dummy terminal is formed in addition to the above terminals. In addition to the above terminals, dummy terminals are also formed in the second terminal portion 22. A Z-phase magnetoresistive pattern 25 (Z) for detecting the origin position is formed in a central region in the longitudinal direction of the rigid substrate 10 in an area adjacent to the magnetoresistive pattern, and the second terminal In the portion 22, a power supply terminal 226 (Vcc), a ground terminal 227 (GND), output terminals 228 (Z), and 229 (Z) for the Z-phase magnetoresistive pattern 25 (Z) are also formed.
　このように構成した磁気式リニアエンコーダ１００において、磁気スケール９が磁極の１周期分移動すると、図５（ｃ）に示す正弦波信号ｓｉｎ、ｃｏｓが２周期分、出力される。従って、内挿によって、正弦波信号ｓｉｎ、ｃｏｓからθ＝ｔａｎ-1（ｓｉｎ／ｃｏｓ）を求めれば、磁気センサ装置１と磁気スケール９との相対位置θが分かる。かかる内挿によれば、磁気スケール９に形成した磁極ピッチ以上の分解能を得ることができる。 In the magnetic linear encoder 100 configured as described above, when the magnetic scale 9 moves by one period of the magnetic pole, the sine wave signals sin and cos shown in FIG. 5C are output by two periods. Therefore, if θ = tan −1 (sin / cos) is obtained from the sine wave signals sin and cos by interpolation, the relative position θ between the magnetic sensor device 1 and the magnetic scale 9 can be obtained. According to such interpolation, a resolution higher than the magnetic pole pitch formed on the magnetic scale 9 can be obtained.
　なお、本形態において、磁気抵抗パターン２５（＋ａ）、２５（－ａ）、２５（＋ｂ）、２５（－ｂ）は、抵抗値の飽和感度領域以上の磁界強度で回転磁界を検出する。すなわち、隣接するトラック９１の境界部分９１２においては、各磁気抵抗パターン２５（＋ａ）、２５（－ａ）、２５（＋ｂ）、２５（－ｂ）の抵抗値の飽和感度領域以上の磁界強度で面内方向の向きが周方向で漸次に変化する回転磁界が発生する。飽和感度領域とは、一般的に、抵抗値変化量ｋが、磁界強度Ｈと近似的に「ｋ∝Ｈ２」の式で表すことができる領域以外の領域をいう。また、飽和感度領域以上の磁界強度で回転磁界（磁気ベクトルの回転）の方向を検出する際の原理は、強磁性金属からなる磁気抵抗パターン２５（＋ａ）、２５（－ａ）、２５（＋ｂ）、２５（－ｂ）に通電した状態で、抵抗値が飽和する磁界強度を印加したとき、磁界と電流方向がなす角度θと、磁気抵抗パターン２５（＋ａ）、２５（－ａ）、２５（＋ｂ）、２５（－ｂ）の抵抗値Ｒとの間には、下式
　　　Ｒ＝Ｒ０－ｋ×ｓｉｎ２θ
　　　　　Ｒ０：無磁界中での抵抗値
　　　　　ｋ：抵抗値変化量（飽和感度領域以上のときは定数）
で示す関係があることを利用するものである。このような原理に基づいて回転磁界を検出すれば、角度θが変化すると抵抗値Ｒが正弦波に沿って変化するので、波形品質の高い正弦波信号ｓｉｎ、ｃｏｓを得ることができる。 In this embodiment, the magnetoresistive patterns 25 (+ a), 25 (−a), 25 (+ b), and 25 (−b) detect a rotating magnetic field with a magnetic field strength equal to or higher than the saturation sensitivity region of the resistance value. That is, at the boundary portion 912 of the adjacent track 91, the magnetic field intensity is greater than the saturation sensitivity region of the resistance value of each magnetoresistive pattern 25 (+ a), 25 (−a), 25 (+ b), 25 (−b). A rotating magnetic field is generated in which the in-plane direction gradually changes in the circumferential direction. The saturation sensitivity region generally refers to a region other than the region in which the resistance value change amount k can be approximately expressed by the magnetic field strength H and the expression “k∝H2”. The principle of detecting the direction of the rotating magnetic field (rotation of the magnetic vector) with a magnetic field strength equal to or higher than the saturation sensitivity region is based on magnetoresistive patterns 25 (+ a), 25 (−a), 25 (+ b) made of ferromagnetic metal. ), 25 (−b), when a magnetic field intensity that saturates the resistance value is applied, the angle θ formed by the magnetic field and the current direction, and the magnetoresistive patterns 25 (+ a), 25 (−a), 25 Between the resistance value R of (+ b) and 25 (−b), R = R0−k × sin2θ
R0: resistance value in a non-magnetic field k: resistance value change (a constant when the saturation sensitivity region is exceeded)
The fact that there is a relationship indicated by If the rotating magnetic field is detected based on such a principle, the resistance value R changes along the sine wave when the angle θ changes, so that sine wave signals sin and cos with high waveform quality can be obtained.
　（磁気スケール９の詳細構成）
　再び図１において、本形態において、磁気式リニアエンコーダ１００は、オープンタイプのリニアエンコーダであり、かかるオープンタイプのリニアエンコーダでは、磁気センサ装置１と磁気スケール９とが独立して固定体および可動体に搭載される。このため、磁気センサ装置１と磁気スケール９とは、非接触状態で相対移動する。また、図２に示す磁気抵抗素子２５と永久磁石９６との間隔が０．１５ｍｍから０．３５ｍｍである。かかる構成に対応して、本形態において、磁気スケール９は、以下の構成を有している。 (Detailed configuration of magnetic scale 9)
In FIG. 1 again, in this embodiment, the magnetic linear encoder 100 is an open type linear encoder. In such an open type linear encoder, the magnetic sensor device 1 and the magnetic scale 9 are independently a fixed body and a movable body. Mounted on. For this reason, the magnetic sensor device 1 and the magnetic scale 9 relatively move in a non-contact state. Further, the distance between the magnetoresistive element 25 and the permanent magnet 96 shown in FIG. 2 is 0.15 mm to 0.35 mm. Corresponding to this configuration, in the present embodiment, the magnetic scale 9 has the following configuration.
　まず、磁気スケール９は、金属製のベース板９５と、ベース板９５の磁気センサ装置１側の一方面９５０に設けられた永久磁石９６とを有している。また、永久磁石９６の磁気センサ装置１側の面９６０は、露出した状態にあり、保護シート等で覆われていない。 First, the magnetic scale 9 has a metal base plate 95 and a permanent magnet 96 provided on one surface 950 of the base plate 95 on the magnetic sensor device 1 side. Further, the surface 960 of the permanent magnet 96 on the magnetic sensor device 1 side is exposed and is not covered with a protective sheet or the like.
　本形態において、永久磁石９６は、磁性粉と樹脂とを含んでベース板９５の一方面９５０に形成された磁性塗膜９７からなる。本形態において、樹脂は、エポキシ樹脂からなる。磁性粉は、フェライト系磁性粉である。より具体的には、永久磁石９６は、フェライト系磁性粉として、ストロンチウムフェライトと、バリウムフェライトとを含んでいる。例えば、永久磁石９６は、フェライト系磁性粉として、ストロンチウムフェライトと、バリウムフェライトとを８０％～９０％：２０％～１０％の重量比で含んでおり、永久磁石９６におけるフェライト系磁性粉の比率は約７０重量％である。 In this embodiment, the permanent magnet 96 is made of a magnetic coating film 97 formed on one surface 950 of the base plate 95 including magnetic powder and resin. In this embodiment, the resin is made of an epoxy resin. The magnetic powder is a ferrite-based magnetic powder. More specifically, the permanent magnet 96 contains strontium ferrite and barium ferrite as ferrite-based magnetic powder. For example, the permanent magnet 96 contains strontium ferrite and barium ferrite in a weight ratio of 80% to 90%: 20% to 10% as ferrite magnetic powder, and the ratio of the ferrite magnetic powder in the permanent magnet 96 Is about 70% by weight.
　ここで、永久磁石９６は、垂直配向されている。すなわち、磁性塗膜９７に含まれる磁性粉は、磁化容易軸をベース板９５の一方面９５０に垂直な方向（磁性塗膜９７の膜厚方向）に向けている。より具体的には、ストロンチウムフェライトおよびバリウムフェライトは、六角板の粉末からなるため、六角板が積層するように重なった状態にある。かかる構成は、磁性塗膜９７の形成途中に外部磁界を加え、磁石粉末の磁化容易軸を揃えることにより実現することができる。従って、永久磁石９６は、異方性磁石として構成されており、等方性磁石よりも強い磁力を発生させる。 Here, the permanent magnet 96 is vertically oriented. That is, the magnetic powder contained in the magnetic coating 97 has the easy axis of magnetization in the direction perpendicular to the one surface 950 of the base plate 95 (the film thickness direction of the magnetic coating 97). More specifically, since strontium ferrite and barium ferrite are made of hexagonal plate powder, the hexagonal plates are stacked so as to be laminated. Such a configuration can be realized by applying an external magnetic field during the formation of the magnetic coating film 97 and aligning the easy magnetization axes of the magnet powder. Therefore, the permanent magnet 96 is configured as an anisotropic magnet and generates a magnetic force stronger than that of the isotropic magnet.
　本形態において、永久磁石９６（磁性塗膜９７）の厚さは、４００μｍから５００μｍであり、ベース板９５は、アルミニウムやアルミニウム合金等からなる非磁性の金属製である。 In this embodiment, the permanent magnet 96 (magnetic coating film 97) has a thickness of 400 μm to 500 μm, and the base plate 95 is made of a nonmagnetic metal such as aluminum or an aluminum alloy.
　かかる構成の磁気スケール９は、磁性粉、樹脂および溶媒を含む塗液をスプレー等によってベース板９５の一方面９５０に１００μｍ程度塗布した後、空気の吹き付けおよび予備乾燥等によって溶媒を除去し、この状態で外部磁界を加えて磁性粉を配向させた後、樹脂を仮硬化させる。そして、上記の工程を繰り返し行って、磁性塗膜９７を所定の厚さに形成する。 The magnetic scale 9 having such a structure is formed by applying a coating liquid containing magnetic powder, resin, and solvent to the one surface 950 of the base plate 95 by spraying or the like about 100 μm, and then removing the solvent by blowing air, pre-drying, etc. After applying an external magnetic field in the state to orient the magnetic powder, the resin is temporarily cured. Then, the above process is repeated to form the magnetic coating film 97 with a predetermined thickness.
　次に、樹脂を本硬化させた後、磁性塗膜９７を研磨する。本形態では、研磨によって、十点平均粗さＲｚjisを５μｍ以下とする。「十点平均粗さＲｚjis」とは、粗さ曲線からその平均線の方向に基準長さだけを抜き取り、この抜取り部分の平均線から縦倍率の方向に測定する。そして、最も高い山頂から５番目までの山頂の標高の絶対値の平均値と、最も低い谷底から５番目までの谷底の標高の絶対値の平均値との和を求め、この値をマイクロメートル（μm）で表したものである。 Next, after the resin is fully cured, the magnetic coating film 97 is polished. In this embodiment, the ten-point average roughness Rzjis is set to 5 μm or less by polishing. “10-point average roughness Rzjis” is obtained by extracting only the reference length from the roughness curve in the direction of the average line and measuring in the direction of the vertical magnification from the average line of the extracted portion. Then, the sum of the average absolute value of the elevation from the highest peak to the fifth and the average absolute value of the elevation from the lowest valley to the fifth is obtained, and this value is calculated in micrometers ( μm).
　そして、磁性塗膜９７に対して、リングヘッド（双極ヘッド）から磁界を印加して磁性塗膜９７に着磁を行い、永久磁石９６を得る。 Then, a magnetic field is applied to the magnetic coating film 97 from a ring head (bipolar head) to magnetize the magnetic coating film 97 to obtain a permanent magnet 96.
　（評価結果）
　図６は、永久磁石９６の平面度を示すグラフであり、図６には、本形態の永久磁石９６（磁性塗膜９７）の平面度を実線で示し、比較例として、ゴムマグネットの平面度を点線で示してある。図６に示す平面度は、対称表面の上下を平行平面で挟み込んだ場合の平面間の空間の距離をμｍ単位で表現した数値である。 (Evaluation results)
FIG. 6 is a graph showing the flatness of the permanent magnet 96. In FIG. 6, the flatness of the permanent magnet 96 (magnetic coating film 97) of this embodiment is shown by a solid line. As a comparative example, the flatness of a rubber magnet is shown. Is indicated by a dotted line. The flatness shown in FIG. 6 is a numerical value expressing the distance of the space between planes when the upper and lower sides of the symmetrical surface are sandwiched between parallel planes in units of μm.
　図７は、永久磁石９６の着磁精度を示すグラフであり、図７（ａ）には、比較例として、ゴムマグネットの着磁精度を示し、図７（ｂ）には、本形態の永久磁石９６（磁性塗膜９７）の着磁精度を示してある。 FIG. 7 is a graph showing the magnetization accuracy of the permanent magnet 96, FIG. 7A shows the magnetization accuracy of a rubber magnet as a comparative example, and FIG. 7B shows the permanent accuracy of this embodiment. The magnetization accuracy of the magnet 96 (magnetic coating film 97) is shown.
　図８は、磁石型リニアエンコーダの内挿精度（分解能）を示すグラフである。図８（ａ）、（ｂ）、（ｃ）には、本形態の永久磁石９６（磁性塗膜９７）を磁気式リニアエンコーダ１００に用い、磁気抵抗素子２５と永久磁石９６との間隔（ｇａｐ）を０．１５ｍｍ、０．２５ｍｍ、０．３５ｍｍに設定した場合の内挿精度を示すグラフである。図８（ｄ）、（ｅ）、（ｆ）には、比較例として、ゴムマグネットを磁気式リニアエンコーダ１００に用い、磁気抵抗素子２５と永久磁石９６との間隔（ｇａｐ）を０．１５ｍｍ、０．２５ｍｍ、０．３５ｍｍに設定した場合の内挿精度を示すグラフである。 FIG. 8 is a graph showing the interpolation accuracy (resolution) of the magnet type linear encoder. 8A, 8B, and 8C, the permanent magnet 96 (magnetic coating film 97) of this embodiment is used in the magnetic linear encoder 100, and the distance (gap) between the magnetoresistive element 25 and the permanent magnet 96 is shown. ) Is set to 0.15 mm, 0.25 mm, and 0.35 mm. 8D, 8E, and 8F, as a comparative example, a rubber magnet is used for the magnetic linear encoder 100, and a gap (gap) between the magnetoresistive element 25 and the permanent magnet 96 is 0.15 mm. It is a graph which shows the interpolation precision at the time of setting to 0.25 mm and 0.35 mm.
　図９は、永久磁石９６（磁性塗膜９７）の厚さと、磁気式リニアエンコーダ１００の特性との関係を示すグラフであり、図９（ａ）、（ｂ）、（ｃ）には、内挿精度、ヒステリシス誤差、表面磁束密度を示してある。 FIG. 9 is a graph showing the relationship between the thickness of the permanent magnet 96 (magnetic coating film 97) and the characteristics of the magnetic linear encoder 100. FIGS. 9 (a), (b), and (c) The insertion accuracy, hysteresis error, and surface magnetic flux density are shown.
　図１０は、永久磁石９６（磁性塗膜９７）における配向着磁の効果を示すグラフである。図１０（ａ）、（ｂ）には、磁性塗膜９７に水平配向を行った場合、磁性塗膜９７に垂直配向を行った場合、磁性塗膜９７に配向を行わなかった場合、ゴムマグネットに垂直配向を行った場合の内挿精度、およびヒステリシス誤差を示してある。なお、図１０には、磁気抵抗素子２５と永久磁石９６との間隔（ｇａｐ）を０．１５ｍｍ、０．２５ｍｍ、０．３５ｍｍに設定した場合を各々、＊１、＊２、＊３を付した棒グラフで示してある。 FIG. 10 is a graph showing the effect of orientation magnetization in the permanent magnet 96 (magnetic coating film 97). 10 (a) and 10 (b), when the magnetic coating film 97 is horizontally oriented, when the magnetic coating film 97 is vertically oriented, when the magnetic coating film 97 is not oriented, the rubber magnet The interpolation accuracy and the hysteresis error when vertical alignment is performed are shown. In FIG. 10, * 1, * 2, and * 3 are given when the gaps (gap) between the magnetoresistive element 25 and the permanent magnet 96 are set to 0.15 mm, 0.25 mm, and 0.35 mm, respectively. This is shown in a bar graph.
　図１１は、磁気スケール９のベース板９５の材質の影響を示すグラフである。図１１（ａ）、（ｂ）、（ｃ）には、ベース板９５がアルミニウム（Ａｌ／非磁性）からなる場合、ベース板９５がアルミニウム・鉄積層合金（Ａｌ／非磁性・Ｆｅ／磁性）からなる場合、ベース板９５が鉄（Ｆｅ／磁性）からなる場合のアナログ振幅、内挿精度、およびヒステリシス誤差を示してある。 FIG. 11 is a graph showing the influence of the material of the base plate 95 of the magnetic scale 9. 11A, 11B, and 11C, when the base plate 95 is made of aluminum (Al / nonmagnetic), the base plate 95 is made of an aluminum / iron laminated alloy (Al / nonmagnetic / Fe / magnetic). When the base plate 95 is made of, the analog amplitude, the interpolation accuracy, and the hysteresis error when the base plate 95 is made of iron (Fe / magnetic) are shown.
　図６に示すように、永久磁石９６（磁性塗膜９７）では平面度が高いのに対して、ゴムマグネットでは平面度が低い。すなわち、永久磁石９６（磁性塗膜９７）の表面は、ゴムマグネットに対して研磨が効果的に行われるため、表面粗さが小であるとともに、うねりも小さい。このため、図７（ｂ）に示すように、永久磁石９６（磁性塗膜９７）では着磁精度が高いのに対して、ゴムマグネットでは着磁精度が低い。従って、図８に示すように、永久磁石９６（磁性塗膜９７）では内挿精度が安定しているのに対して、ゴムマグネットでは内挿精度の安定性が低い。例えば、永久磁石９６（磁性塗膜９７）では、磁気抵抗素子２５と永久磁石９６との間隔（ｇａｐ）が０．１５ｍｍ、０．２５ｍｍ、０．３５ｍｍのとき、内挿精度が１．５０μｍ、１．５０μｍ、１．９０μｍであるのに対して、ゴムマグネットでは、磁気抵抗素子２５と永久磁石９６との間隔（ｇａｐ）が０．１５ｍｍ、０．２５ｍｍ、０．３５ｍｍのとき、内挿精度が１．７０μｍ、１．６０μｍ、２．１０μｍである。なお、永久磁石９６（磁性塗膜９７）では、磁気抵抗素子２５と永久磁石９６との間隔（ｇａｐ）が０．１５ｍｍ、０．２５ｍｍ、０．３５ｍｍのとき、ヒステリシス誤差が０．６０μｍ、０．６０μｍ、１．００μｍであるのに対して、ゴムマグネットでは、磁気抵抗素子２５と永久磁石９６との間隔（ｇａｐ）が０．１５ｍｍ、０．２５ｍｍ、０．３５ｍｍのとき、ヒステリシス誤差が０．５０μｍ、０．６０μｍ、０．７０μｍである。 As shown in FIG. 6, the permanent magnet 96 (magnetic coating film 97) has high flatness, whereas the rubber magnet has low flatness. That is, since the surface of the permanent magnet 96 (magnetic coating film 97) is effectively polished on the rubber magnet, the surface roughness is small and the undulation is small. For this reason, as shown in FIG. 7B, the permanent magnet 96 (magnetic coating film 97) has high magnetization accuracy, whereas the rubber magnet has low magnetization accuracy. Therefore, as shown in FIG. 8, the permanent magnet 96 (magnetic coating film 97) has a stable interpolation accuracy, whereas the rubber magnet has a low stability of the interpolation accuracy. For example, in the permanent magnet 96 (magnetic coating film 97), when the gap (gap) between the magnetoresistive element 25 and the permanent magnet 96 is 0.15 mm, 0.25 mm, and 0.35 mm, the interpolation accuracy is 1.50 μm, In contrast to 1.50 μm and 1.90 μm, in the rubber magnet, when the gap (gap) between the magnetoresistive element 25 and the permanent magnet 96 is 0.15 mm, 0.25 mm, and 0.35 mm, the interpolation accuracy is Are 1.70 μm, 1.60 μm, and 2.10 μm. In the permanent magnet 96 (magnetic coating film 97), when the gap (gap) between the magnetoresistive element 25 and the permanent magnet 96 is 0.15 mm, 0.25 mm, and 0.35 mm, the hysteresis error is 0.60 μm, 0. In contrast to the .60 μm and 1.00 μm, the hysteresis error of the rubber magnet is 0 when the gap (gap) between the magnetoresistive element 25 and the permanent magnet 96 is 0.15 mm, 0.25 mm, and 0.35 mm. .50 μm, 0.60 μm, and 0.70 μm.
　また、図９に示すように、永久磁石９６（磁性塗膜９７）の厚さに関しては、４００μｍや５００μｍの場合、３００μｍや６００μｍの場合に比して内挿精度が高い。その理由は、永久磁石９６（磁性塗膜９７）に対する着磁の際、４００μｍや５００μｍであれば、着磁が適正に行われるのに対して、３００μｍでは、磁性塗膜９７が薄くて必要な磁束密度が得られないためと考えられる。また、６００μｍでは、磁性塗膜９７が厚くて、十分に着磁ができないためと考えられる。 Also, as shown in FIG. 9, regarding the thickness of the permanent magnet 96 (magnetic coating film 97), the interpolation accuracy is higher in the case of 400 μm or 500 μm than in the case of 300 μm or 600 μm. The reason is that when magnetizing the permanent magnet 96 (magnetic coating film 97), if 400 μm or 500 μm, the magnetization is properly performed, whereas at 300 μm, the magnetic coating film 97 is thin and necessary. This is probably because the magnetic flux density cannot be obtained. Further, at 600 μm, it is considered that the magnetic coating film 97 is thick and cannot be sufficiently magnetized.
　また、図１０に示すように、磁性塗膜９７に垂直配向を行った場合、磁性塗膜９７に水平配向を行った場合や配向を行わなかった場合に比して内挿精度に優れており、磁性塗膜９７に垂直配向を行えば、磁気抵抗素子２５と永久磁石９６との間隔（ｇａｐ）を０．１５ｍｍ、０．２５ｍｍ、０．３５ｍｍに設定した場合、十分な内挿精度を得ることができる。特に、磁気抵抗素子２５と永久磁石９６との間隔（ｇａｐ）が０．１５ｍｍや０．２５ｍｍである場合、０．３５ｍｍに設定した場合に比して、内挿精度が優れている。 In addition, as shown in FIG. 10, when the magnetic coating film 97 is vertically aligned, the accuracy of interpolation is excellent as compared with the case where the magnetic coating film 97 is horizontally aligned or not aligned. When the magnetic coating film 97 is vertically oriented, sufficient interpolation accuracy is obtained when the gap (gap) between the magnetoresistive element 25 and the permanent magnet 96 is set to 0.15 mm, 0.25 mm, and 0.35 mm. be able to. In particular, when the gap (gap) between the magnetoresistive element 25 and the permanent magnet 96 is 0.15 mm or 0.25 mm, the interpolation accuracy is excellent as compared with the case where it is set to 0.35 mm.
　また、図１１に示すように、ベース板９５の材質に関しては、アルミニウムやアルミニウム合金等の非磁性金属を用いた場合、磁性金属を用いた場合に比して、永久磁石９６の厚さが比較的薄い場合でも、十分なアナログ振幅や内挿精度を得ることができる。その理由は、磁性塗膜９７が比較的薄い場合でも、着磁の際、ベース板９５の影響が及びにくいためと考えられる。 Also, as shown in FIG. 11, regarding the material of the base plate 95, the thickness of the permanent magnet 96 is compared when a nonmagnetic metal such as aluminum or aluminum alloy is used compared to when a magnetic metal is used. Even in the case of a thin film, sufficient analog amplitude and interpolation accuracy can be obtained. The reason is considered to be that even when the magnetic coating film 97 is relatively thin, the influence of the base plate 95 is hardly exerted during magnetization.
　（本形態の主な効果）
　以上説明したように、本形態の磁気式リニアエンコーダ１００では、磁気スケール９に用いた永久磁石９６が、磁性粉と樹脂とを含む磁性塗膜９７からなるため、ゴムマグネットに比して、高い平面度を得ることができる。また、本形態では、金属製のベース板９５を用いているため、永久磁石９６に高い平面度を得やすい。従って、磁気スケール９の永久磁石９６に対する着磁精度を向上することができるので、磁気式リニアエンコーダ１００の分解能等を向上することができる。 (Main effects of this form)
As described above, in the magnetic linear encoder 100 of the present embodiment, the permanent magnet 96 used for the magnetic scale 9 is composed of the magnetic coating film 97 containing magnetic powder and resin, so that it is higher than a rubber magnet. Flatness can be obtained. In this embodiment, since the metal base plate 95 is used, it is easy to obtain high flatness in the permanent magnet 96. Therefore, since the magnetization accuracy of the magnetic scale 9 with respect to the permanent magnet 96 can be improved, the resolution and the like of the magnetic linear encoder 100 can be improved.
　また、磁性塗膜９７の厚さは、４００μｍから５００μｍであるため、十分な深さまで着磁することができる。従って、分解能の向上や、ヒステリシス誤差の低減を図ることができる。 Further, since the thickness of the magnetic coating film 97 is 400 μm to 500 μm, it can be magnetized to a sufficient depth. Therefore, the resolution can be improved and the hysteresis error can be reduced.
　また、ベース板９５は、非磁性の金属製であるため、リングゲートによって着磁を行っても、ベース板９５の影響が発生しにくい。 Further, since the base plate 95 is made of a non-magnetic metal, the influence of the base plate 95 hardly occurs even when the base plate 95 is magnetized by the ring gate.
　また、永久磁石９６は、垂直配向されているため、分解能の向上や、ヒステリシス誤差の低減を図ることができる。また、磁性塗膜９７に用いた磁性粉は、フェライト系磁性粉であるため、内挿によって位置等を求めた際、分解能の向上を図ることができる。 Further, since the permanent magnet 96 is vertically oriented, it is possible to improve the resolution and reduce the hysteresis error. Moreover, since the magnetic powder used for the magnetic coating film 97 is a ferrite-based magnetic powder, the resolution can be improved when the position and the like are obtained by interpolation.
　また、永久磁石９６は、磁気センサ装置１側の面が露出状態にあるため、磁気センサ装置１と磁気スケール９との間隔を広く確保することができる。従って、オープンタイプの磁気式リニアエンコーダ１００のように、磁気センサ装置１と磁気スケール９とが非接触状態で相対移動する場合に適している。 Further, since the surface of the permanent magnet 96 on the side of the magnetic sensor device 1 is in an exposed state, a wide interval between the magnetic sensor device 1 and the magnetic scale 9 can be secured. Therefore, it is suitable for the case where the magnetic sensor device 1 and the magnetic scale 9 are relatively moved in a non-contact state like the open type magnetic linear encoder 100.
　この場合、磁気抵抗素子２５と永久磁石９６との間隔が０．１５ｍｍから０．３５ｍｍであれば、磁気センサ装置１と磁気スケール９とが非接触状態で相対移動する場合に適しているとともに、分解能の向上を図ることができる。しかも、本形態でも、磁気抵抗素子２５と永久磁石９６との間に０．１５ｍｍから０．３５ｍｍの間隔を確保した場合でも、磁性塗膜９７の厚さが４００μｍから５００μｍであって、磁性塗膜９７が垂直配向しているため、十分な磁界を発生させることができる。それ故、オープンタイプの磁気式リニアエンコーダ１００のように、磁気センサ装置１と磁気スケール９とが非接触状態で相対移動する場合でも、十分な感度や分解能を得ることができる。 In this case, if the distance between the magnetoresistive element 25 and the permanent magnet 96 is 0.15 mm to 0.35 mm, it is suitable for the relative movement of the magnetic sensor device 1 and the magnetic scale 9 in a non-contact state, The resolution can be improved. In addition, even in this embodiment, even when an interval of 0.15 mm to 0.35 mm is secured between the magnetoresistive element 25 and the permanent magnet 96, the thickness of the magnetic coating film 97 is 400 μm to 500 μm, and the magnetic coating Since the film 97 is vertically aligned, a sufficient magnetic field can be generated. Therefore, sufficient sensitivity and resolution can be obtained even when the magnetic sensor device 1 and the magnetic scale 9 move relative to each other in a non-contact state like the open type magnetic linear encoder 100.
　（他の実施の形態）
　上記実施の形態では、磁極のピッチが１．０ｍｍ以下であるという構成に対応させて、磁性粉としてフェライト系磁性粉を用いたが、磁極のピッチが１．０ｍｍを超える場合、磁性粉としてネオジウム系磁性粉、サマリウム系磁性粉、メタル系等の高磁力磁性粉を用いてもよい。 (Other embodiments)
In the above embodiment, ferrite magnetic powder is used as the magnetic powder in correspondence with the configuration in which the pitch of the magnetic pole is 1.0 mm or less. However, when the pitch of the magnetic pole exceeds 1.0 mm, neodymium is used as the magnetic powder. A high magnetic force magnetic powder such as a magnetic powder, a samarium magnetic powder, or a metal may be used.
　上記形態では、磁気センサ装置１において飽和感度領域以上の磁界強度で回転磁界の方向を検出する磁気式リニアエンコーダ１００に本発明を適用したが、一定方向の磁界の強弱により位置検出するタイプの磁気式リニアエンコーダ１００や、飽和感度領域以外の領域の磁界強度で回転磁界の方向を検出するタイプの磁気式リニアエンコーダ１００に本発明を適用してもよい。 In the above embodiment, the present invention is applied to the magnetic linear encoder 100 that detects the direction of the rotating magnetic field with a magnetic field strength equal to or higher than the saturation sensitivity region in the magnetic sensor device 1. The present invention may be applied to the linear encoder 100 and the magnetic linear encoder 100 of a type that detects the direction of the rotating magnetic field with the magnetic field strength in a region other than the saturation sensitivity region.
　上記実施の形態では、ベース板９５が非磁性材料からなっていたが、磁性材料からなるベース板９５を用いてもよい。また、永久磁石９６の表面９６０に保護層が形成されている構成であってもよい。上記実施の形態の磁気スケール９において、トラック９１の数が３つであったが、トラック９１の数が１つ、２つ、３つ以上である場合に本発明を適用してもよい。上記実施の形態では、永久磁石９６が垂直配向されていたが、水平配向されている場合に本発明を適用してもよい。上記実施の形態において、永久磁石９６（磁性塗膜９７）の樹脂がエポキシ樹脂であったが、樹脂がポリウレタン樹脂、フェノール樹脂、アクリル樹脂、ビニル樹脂、ポリエステル樹脂等であってもよい。 In the above embodiment, the base plate 95 is made of a nonmagnetic material, but a base plate 95 made of a magnetic material may be used. Moreover, the structure in which the protective layer is formed in the surface 960 of the permanent magnet 96 may be sufficient. In the magnetic scale 9 of the above embodiment, the number of tracks 91 is three. However, the present invention may be applied when the number of tracks 91 is one, two, three, or more. In the above embodiment, the permanent magnet 96 is vertically oriented. However, the present invention may be applied to a case where the permanent magnet 96 is horizontally oriented. In the above embodiment, the resin of the permanent magnet 96 (magnetic coating film 97) is an epoxy resin, but the resin may be a polyurethane resin, a phenol resin, an acrylic resin, a vinyl resin, a polyester resin, or the like.
１　磁気センサ装置
９　磁気スケール
１０　磁気抵抗素子
９１　トラック
９５　ベース板
９６　永久磁石
９７　磁性塗膜
１００　磁気式リニアエンコーダ DESCRIPTION OF SYMBOLS 1 Magnetic sensor apparatus 9 Magnetic scale 10 Magnetoresistive element 91 Track 95 Base plate 96 Permanent magnet 97 Magnetic coating film 100 Magnetic linear encoder

Claims (11)

  1. 　永久磁石を備えた磁気スケールと、該磁気スケールからの磁界を検出する磁気抵抗素子を備えた磁気センサ装置と、を有し、前記永久磁石には、前記磁気センサ装置と前記磁気スケールとの相対移動方向に沿ってＮ極とＳ極とが交互に並ぶトラックが形成されている磁気式リニアエンコーダにおいて、
    　前記永久磁石は、磁性粉と樹脂とを含んで金属製のベース板の一方側の面に形成された磁性塗膜からなることを特徴とする磁気式リニアエンコーダ。     A magnetic scale provided with a permanent magnet, and a magnetic sensor device provided with a magnetoresistive element for detecting a magnetic field from the magnetic scale, and the permanent magnet has a relative relationship between the magnetic sensor device and the magnetic scale. In the magnetic linear encoder in which tracks in which N poles and S poles are alternately arranged along the moving direction are formed,
    The permanent magnet includes a magnetic coating film formed on one surface of a metal base plate containing magnetic powder and resin.
  2. 　前記磁性塗膜の厚さは、４００μｍから５００μｍであることを特徴とする請求項１に記載の磁気式リニアエンコーダ。 The magnetic linear encoder according to claim 1, wherein the magnetic coating film has a thickness of 400 µm to 500 µm.
  3. 　前記ベース板は、非磁性の金属製であることを特徴とする請求項１または２に記載の磁気式リニアエンコーダ。 3. The magnetic linear encoder according to claim 1, wherein the base plate is made of a nonmagnetic metal.
  4. 　前記永久磁石は、前記磁性粉の磁化容易軸が前記磁性塗膜の膜厚方向に向いていることを特徴とする請求項１乃至３の何れか一項に記載の磁気式リニアエンコーダ。 The magnetic linear encoder according to any one of claims 1 to 3, wherein the permanent magnet has an easy magnetization axis of the magnetic powder oriented in a film thickness direction of the magnetic coating film.
  5. 　前記磁性粉は、フェライト系磁性粉であることを特徴とする請求項１乃至４の何れか一項に記載の磁気式リニアエンコーダ。 The magnetic linear encoder according to any one of claims 1 to 4, wherein the magnetic powder is a ferrite-based magnetic powder.
  6. 　前記永久磁石は、前記フェライト系磁性粉として、ストロンチウムフェライトと、バリウムフェライトを含んでいることを特徴とする請求項５に記載の磁気式リニアエンコーダ。 The magnetic linear encoder according to claim 5, wherein the permanent magnet includes strontium ferrite and barium ferrite as the ferrite magnetic powder.
  7. 　前記磁気センサ装置と前記磁気スケールとは、非接触状態で相対移動することを特徴とする請求項１乃至６の何れか一項に記載の磁気式リニアエンコーダ。 The magnetic linear encoder according to any one of claims 1 to 6, wherein the magnetic sensor device and the magnetic scale are relatively moved in a non-contact state.
  8. 　前記永久磁石は、前記磁気センサ装置側の面が露出状態にあることを特徴とする請求項７に記載の磁気式リニアエンコーダ。 The magnetic linear encoder according to claim 7, wherein a surface of the permanent magnet on the magnetic sensor device side is exposed.
  9. 　前記磁気抵抗素子と前記永久磁石との間隔が０．１５ｍｍから０．３５ｍｍであることを特徴とする請求項７または８に記載の磁気式リニアエンコーダ。 The magnetic linear encoder according to claim 7 or 8, wherein a distance between the magnetoresistive element and the permanent magnet is 0.15 mm to 0.35 mm.
  10. 　前記磁気スケールにおいて、前記トラックは、前記相対移動方向と交差する方向に複数列、設けられ、
    　前記複数列のトラックにおいて、隣り合う２つのトラックでは、前記相対移動方向においてＮ極とＳ極とがずれていることを特徴とする請求項１乃至９の何れか一項に記載の磁気式リニアエンコーダ。     In the magnetic scale, the tracks are provided in a plurality of rows in a direction intersecting the relative movement direction,
    10. The magnetic linear device according to claim 1, wherein, in the plurality of rows of tracks, in two adjacent tracks, a north pole and a south pole are shifted in the relative movement direction. Encoder.
  11. 　前記磁気抵抗素子は、前記永久磁石の回転磁界を検出することを特徴とする請求項１０に記載の磁気式リニアエンコーダ。 The magnetic linear encoder according to claim 10, wherein the magnetoresistive element detects a rotating magnetic field of the permanent magnet.
PCT/JP2015/070704 2014-08-07 2015-07-21 Magnetic linear encoder WO2016021401A1 (en)

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