WO2013145851A1 - 回転角計測装置及びこの回転角計測装置を備えた回転機械 - Google Patents

回転角計測装置及びこの回転角計測装置を備えた回転機械 Download PDF

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Publication number
WO2013145851A1
WO2013145851A1 PCT/JP2013/052303 JP2013052303W WO2013145851A1 WO 2013145851 A1 WO2013145851 A1 WO 2013145851A1 JP 2013052303 W JP2013052303 W JP 2013052303W WO 2013145851 A1 WO2013145851 A1 WO 2013145851A1
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Prior art keywords
magnetic
rotation angle
pole
bypass
yoke
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PCT/JP2013/052303
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English (en)
French (fr)
Japanese (ja)
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鈴木　睦三
隆史 松村
準二 小野塚
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日立オートモティブシステムズ株式会社
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Publication of WO2013145851A1 publication Critical patent/WO2013145851A1/ja

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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
    • G01D5/2451—Incremental encoders
    • 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
    • G01D2205/00—Indexing scheme relating to details of means for transferring or converting the output of a sensing member
    • G01D2205/40—Position sensors comprising arrangements for concentrating or redirecting magnetic flux

Definitions

  • the present invention relates to a rotation angle measuring device using a magnetic sensor and a rotary machine equipped with the rotation angle measuring device, and more particularly to a rotation angle measuring device capable of obtaining an accurate rotation angle by absorbing a mounting error of the magnetic sensor, and The present invention relates to a rotary machine equipped with this rotation angle measuring device.
  • a rotating body is measured by installing a magnetic flux generator, such as a magnet, on the rotating body, and installing a magnetic sensor at a position where the magnetic flux generated by the magnetic flux generator can reach. It is known that it can be done. Specifically, when the rotating body rotates, the direction of the magnetic flux generated by the magnetic flux generator also rotates, so the rotational position (rotation angle) of the rotating body can be measured by detecting the direction of the magnetic flux with a magnetic sensor. This is used in many industrial fields as a rotation angle measuring device.
  • the magnetic sensors are roughly classified into a magnetic field strength measuring sensor that outputs a signal corresponding to the magnetic field strength and a magnetic field direction measuring sensor that outputs a signal corresponding to the magnetic field direction.
  • the magnetic field direction measuring sensor is also called a vector type magnetic sensor because it measures the magnetic field direction as a vector.
  • Magnetic field direction measurement sensors include (1) Hall-effect elements as magnetic field sensitive elements and (2) Magneto-resistance elements as magnetic field sensitive elements. The details will be described below.
  • the Hall effect element itself is an element that outputs a signal corresponding to the magnetic field strength.
  • the spatial difference in magnetic field strength is measured, and the cosine component (COS component) and sine component (SIN component) in the magnetic field direction are detected, so that the direction of the magnetic field is met.
  • Output signal since the signal according to the magnetic field direction is output, it can be said that this is a magnetic field direction measurement sensor.
  • This type of magnetic sensor converts a magnetic field direction into a magnetic field strength difference by converging a magnetic field with a magnetic material, and measures the difference with a plurality of Hall effect elements. Since this also outputs a signal corresponding to the magnetic field direction, it can be said to be a magnetic field direction measurement sensor.
  • the magnetoresistive element is an element whose electric resistance changes according to the strength of the magnetic field and the direction of the magnetic field.
  • Magnetoresistive elements include anisotropic magnetoresistive elements (Anisotropic Magneto-resistance, hereinafter referred to as “AMR elements”), giant magnetoresistive elements (Giant Magneto-resistance, hereinafter referred to as “GMR elements”), tunnel magnetoresistive elements ( Tunneling (Magneto-resistance, hereafter referred to as “TMR element”).
  • the electrical resistance of the AMR element varies depending on the angle formed by the direction of the magnetic field and the direction of the current. By appropriately combining elements with different current directions, a signal corresponding to the magnetic field angle is output.
  • the GMR element has a configuration in which a fixed magnetic layer and a free magnetic layer are stacked via a spacer layer. A signal corresponding to the magnetic field angle is output by appropriately combining elements in which the spin direction (magnetization direction) of the fixed magnetization layer is changed.
  • a GMR element having a fixed magnetic layer is also called a spin-valve type GMR element.
  • the rotation angle sensor using a magnetic sensor is a non-contact type.
  • the non-contact type means that the sensor that is a detector for detecting the rotational position and the rotating body are not in mechanical contact with each other. Even when used for a long period of time, mechanical wear does not occur and a highly reliable sensor can be obtained.
  • a rotation angle sensor using a multipole magnetized magnet as a magnetic flux generator is known.
  • a multipolar magnetized magnet there exists an advantage that a highly accurate rotation angle measuring device may be realizable.
  • the rotation angle measuring device using a multipolar magnet has a problem that it is affected by the magnetizing error of the magnet. In the magnet magnetization process, an error is likely to occur in the magnetized characteristics, that is, the magnetic field distribution generated by the magnet.
  • errors include systematic errors and individual errors.
  • the systematic error is an error inherent to the magnetizing apparatus used, and is a deviation from an ideal magnetic field distribution. This is a reproducible error in the same magnetization process (magnetization lot).
  • the individual error is an error that varies from individual to individual even when manufactured in the same magnetization process (magnetization lot).
  • the magnetizing error of a magnet includes both a systematic error and an individual error.
  • the measured magnetic field angle is converted into a rotation angle based on the relationship between the rotation angle of the magnetic flux generator and the magnetic field angle. Therefore, if there is a magnetization error, there is a problem that a measurement error occurs in the rotation angle.
  • Patent Document 1 Japanese Patent Application Laid-Open No. 2011-002311
  • the magnetic field direction rotates p times during one rotation of the magnet.
  • the rotation angle of the magnet is referred to as “mechanical angle”
  • the angle in the direction of the magnetic field is referred to as “magnetic field angle”.
  • one period of the magnetic field angle is called a “sector”. That is, the magnetic field angle distribution (profile, the correlation between the magnetic field angle and the mechanical angle) when the (2 ⁇ p) polar magnet makes one rotation has p sectors.
  • the magnetic field angle distribution in the sector (correlation between magnetic field angle and mechanical angle) is the same. Therefore, in the case of an ideally magnetized magnet, the rotation angle can be obtained from the measured magnetic field angle.
  • JP-A-7-103790 a method of generating a magnetic field distribution similar to that of a multipolar magnet by combining a dipole magnet magnetized in the direction of the rotation axis and a pair of comb-like magnetic yokes is disclosed in JP-A-7-103790.
  • Patent Document 2 In this method, one comb-teeth yoke is magnetized to the N pole, and the other comb tooth is magnetized to the S pole. Therefore, on the side surface of the two-pole magnet, a magnetic field distribution in which the N pole and the S pole are interchanged is obtained.
  • the magnetic field profile is similar to a multipolar magnet. This method has an advantage that a high-precision magnetic field profile can be realized because the sector interval and the magnetic field profile in the sector are determined by the mechanical processing accuracy of the comb-shaped yoke.
  • JP 2011-002311 A Japanese Patent Laid-Open No. 7-103790
  • An object of the present invention is directed to a rotation angle measuring device having a configuration as described in Patent Document 2, and a rotation angle measuring device capable of absorbing deterioration in rotation angle measurement accuracy due to an installation error of a magnetic sensor installation position. Is to provide.
  • a feature of the present invention is that a bypass magnetic path forming body is provided which is opposed to the N pole side yoke and the S pole side yoke and flows by bypassing the magnetic field lines from the N pole to the S pole generated by the magnet. This is where an unnecessary magnetic field is prevented from affecting the magnetic sensor by the action of the body.
  • the magnetic field component including the rotation angle information can be selectively detected by the magnetic sensor by bypassing the magnetic field component in the rotation axis direction by the bypass magnetic path forming body, and the installation position of the magnetic sensor can be attached. It is possible to reduce deterioration in the measurement accuracy of the rotation angle due to an error.
  • FIG. 3 It is a block diagram for demonstrating the structure of a general rotation angle measuring device, and the generation condition of the magnetic field by a magnet. It is explanatory drawing for demonstrating the horizontal direction component and vertical direction component of the magnetic field shown in FIG. It is a block diagram for demonstrating the structure of the rotation angle measuring device which becomes one Example of this invention, and the flow of a magnetic field.
  • FIG. 3 (a) is a top view seen from the Z-axis (axis) direction, and (b) is a cross-sectional view showing the cross section. It is a characteristic view which shows the correlation of the magnetic field angle and rotation angle by the rotation angle measuring device which becomes one Example of this invention.
  • FIG. 1 It is a block diagram for demonstrating the modification of the rotation angle measuring device assembled
  • the structure of the rotation angle measuring apparatus generally known is shown, (a) is an overall block diagram, and (b) is an exploded view thereof. It is explanatory drawing which shows the magnetization state of the yoke protrusion of the magnetic flux generator which comprises the rotation angle measuring device shown in FIG.
  • FIG. 25 is a characteristic diagram showing a correlation between a magnetic field angle and a rotation angle depending on a mounting position of a magnetic sensor of the rotation angle measuring device shown in FIG. 24. It is a figure which shows the cross-sectional shape of the structural example of a bypass magnetic path formation body. It is a figure which shows the example of arrangement
  • FIG. 24 shows the configuration of the rotation angle measuring device 80.
  • the magnetic flux generator 202 has an annular magnet 211 and two annular yokes 215A and 215B.
  • the magnetic flux generator 202 is fixed to the rotating shaft 121.
  • the rotation center line 226 of the rotation shaft 121 is the Z axis.
  • the magnet 211 is a two-pole magnetized magnet that is magnetized in the direction along the rotation axis 121 as shown in FIG.
  • the yoke 215A and the yoke 215B are magnetic bodies having a comb-like shape.
  • the magnetic flux generator 202 is configured by covering the yokes 215A and 215B from above and below the magnet 211, respectively.
  • the magnetization direction of the magnet 211 is N pole on the upper side and S pole on the lower side
  • the upper yoke 215A is magnetized to N pole
  • the lower yoke 215b is magnetized to S pole.
  • the yoke protrusions 216A magnetized to the N pole and the yoke protrusions 216B magnetized to the S pole are alternately arranged.
  • the horizontal direction component (XY in-plane component orthogonal to the Z direction) of the magnetic field at the side surface position of the magnetic flux generator 202 has a magnetic field distribution similar to that of a multipolar magnetized magnet.
  • the horizontal component of the magnetic field rotates Np times when the magnetic flux generator 202 rotates once. That is, it has Np sectors. This corresponds to a multipolar magnet magnetized with (Np ⁇ 2) poles.
  • FIG. 25 is a cross-sectional view of the yoke protrusion 216 as viewed from the direction of the Z axis (rotation center line 226). The annular portion of the yoke 215A, the magnet 211, etc. are not shown.
  • FIG. 25 it can be seen that when the magnetic sensor is arranged on the X-axis and the magnetic flux generator 202 is rotated once, the horizontal component of the magnetic field is rotated only eight times at the position where the magnetic sensor 70 is arranged.
  • the magnetic field calculation by the finite element method was performed, and the direction of the horizontal (in the XY plane) magnetic field at the location of the magnetic sensor 70 when the magnetic flux generator 202 rotated was quantitatively determined.
  • the horizontal axis represents the rotation angle (mechanical angle) of the magnetic flux generator 202
  • the vertical axis represents the magnetic field angle (magnetic field angle) at the magnetic sensor position.
  • the magnetic field angle rotates 4 times in the range of 0 to 360 ° with a period of 45 ° of the rotation angle (mechanical angle). That is, one sector has a period of 45 °, and there are 4 sectors in a rotation range of 0 to 180 °. Since the range of 180 to 360 ° is the same, it can be seen that there is a magnetic field angle rotation of 8 sectors by one rotation of the magnetic flux generator 202.
  • the “magnetic field angle distribution” indicates a correlation between the rotation angle (mechanical angle) of the magnetic flux generator and the magnetic field angle (magnetic field angle) at the magnetic sensor position.
  • the ideal magnetic field angle distribution is such that the magnetic field angle varies linearly in the range of 0 to 360 ° within one sector. That is, as shown by the broken line in FIG. 26, a straight line connecting the magnetic field angle 0 ° and the magnetic field angle 360 ° between the rotation angle 0 ° and the rotation angle 45 ° is an ideal straight line. The same applies to a rotation angle of 45 ° to a rotation angle of 180 °.
  • the magnetic field distortion error includes a systematic error and an individual error.
  • the magnetic field distortion error is in the range of ⁇ 20 °.
  • the deviation of ⁇ 20 ° is as large as the magnetic field distortion error in the multipolar magnetized magnet, and can be corrected by an appropriate correction method.
  • the results are shown in FIG.
  • the magnetic field angle changes in a range of about ⁇ 60 ° centering on 180 °, and is greatly deviated from the ideal straight line. Deviation from the ideal straight line (magnetic field distortion error) may reach a maximum of 180 ° and is an error amount that is difficult to correct.
  • the measurement accuracy of the rotation angle is greatly deteriorated if the installation position of the magnetic sensor is slightly shifted. It comes to occur.
  • an installation error that is, an installation error always occurs, so that a new problem arises that it is difficult to measure the rotational angle with high accuracy.
  • the inventors diligently investigated and investigated the cause of a significant deterioration in the measurement accuracy of the rotation angle when the installation position of the magnetic sensor slightly shifted in the axial direction. As a result, it was clarified that the detection accuracy of the rotation angle was lowered depending on the installation position for the following reasons.
  • FIG. 1 schematically shows a spatial distribution in the magnetic field direction in the XZ section of the rotation angle measuring device 80.
  • the magnet 211 is a dipole magnet that is magnetized in the Z-axis direction (the direction of the central axis 226 of the rotation axis), it emits a magnetic force line 250 from the N pole toward the S pole.
  • the spatial distribution of the magnetic field lines 250 is generally isotropic at any azimuth (radially viewed from the Z-axis direction, from N pole to S pole).
  • this magnetic field is referred to as a global magnetic field or a global line of magnetic force.
  • the XY in-plane component of the magnetic field by the yoke protrusions 216A and 216B is superimposed on this global magnetic field as a local modulation magnetic field used for detecting the rotation angle.
  • the XY in-plane component of the local modulation magnetic field is information necessary for detecting the rotation angle, and the rotation angle is measured by detecting the change in the XY in-plane component by the magnetic sensor 70.
  • FIG. 2 shows the magnetic field vector at the installation position of the magnetic sensor.
  • the magnetic field B is considered by dividing it into an XY in-plane component (in-plane component) Bip and a Z direction component Bz.
  • of the Z direction component is 6 times or more of the in-plane component
  • the magnetic sensor senses only the in-plane component, the direction of the in-plane component Bip is detected without being affected by the Z-direction component
  • the magnetic sensor 70 detects a component of global magnetic field lines having a horizontal component Bip.
  • the horizontal component thereof is 180 ° regardless of the rotation angle. This is the reason why the magnetic field angle changes around 180 ° as shown by the dotted line in FIG.
  • the present invention provides a technique for suppressing as much as possible the adverse magnetic field lines generated by the magnet 211 caused by the installation position of the magnetic sensor 70.
  • a magnetic field direction measuring sensor configured by a GMR element which is one of magnetoresistive elements is used as the magnetic sensor 70.
  • the magnetic sensor targeted by the present invention is not limited to the GMR sensor, and may be of other types as long as it is a magnetic field direction measuring sensor.
  • the magnetic field direction measurement sensor is a sensor that outputs a signal corresponding to the direction of the magnetic field.
  • the magnetic field direction measurement sensor outputs an AMR sensor (Anisotropic-Magneto-Resistance-sensor) using an anisotropic magnetoresistive element and a signal corresponding to the magnetic field direction using a plurality of Hall elements.
  • FIG. 3 shows the overall configuration of a rotation angle measuring device 80 according to an embodiment of the present invention.
  • the rotation angle measuring device 80 includes a magnetic flux generator 202, a magnetic sensor 70, and a bypass magnetic path forming body 240.
  • the magnetic flux generator 202 is fixed to the rotating shaft 121 that rotates along the rotation center line 226, and rotates in conjunction with the rotation of the rotating shaft 121.
  • the rotation center line 226 is taken as the Z axis.
  • the magnetic flux generator 202 includes a magnet 211 and two yokes 215A and 215B.
  • the magnet 211 is magnetized into two poles of an N pole and an S pole along the direction of the rotation center line 226 in the same manner as that shown in FIG.
  • the magnet 211 has an annular shape (ring shape) and rotates in conjunction with the rotation of the rotating shaft 121.
  • the two yokes 215A and 215B have yoke protrusions 216A and 216B, respectively.
  • the yoke protrusions 216A and 216B are also made of a magnetic material.
  • the yoke protrusions 216 ⁇ / b> A and 216 ⁇ / b> B have a comb-like shape extending on the side surface of the magnet 211.
  • the yoke 215A provided on the N pole side of the magnet 211 may be referred to as an N pole side yoke
  • the yoke 215B provided on the S pole side may be referred to as an S pole side yoke
  • the yoke protrusion 216A of the N pole side yoke 215A may be referred to as an N pole yoke protrusion
  • the yoke protrusion 216B of the S pole side yoke 215B may be referred to as an S pole yoke protrusion.
  • the N pole yoke protrusions 216A and the S pole yoke protrusions 216B are arranged so as to alternately mesh with each other, as shown in FIG.
  • the yoke 215A and the yoke 215B are made of a magnetic material.
  • the magnetic material is a material having a magnetic susceptibility of 10 or more.
  • a material with a high magnetic susceptibility has the property of easily passing magnetic flux.
  • the yoke protrusions 216A and 216B are also made of a magnetic material.
  • the yoke 215A only needs to cover a part of the upper surface of the magnet 211, and does not need to cover the entire upper surface. Moreover, although it is preferable that the magnet 211 and the yoke 215A have a contact portion, it is not always essential. The reason why the contact is preferable is that the magnetic reluctance is lowered by the contact, so that the magnetic flux is effectively supplied from the magnet 211 to the yoke 215A. The same applies to the yoke 215B.
  • the “comb-tooth shape” is not limited to a rectangular protrusion as shown in the drawing, but includes a triangular or semicircular protrusion.
  • the yoke protrusions 216A magnetized in the N pole and the yoke protrusions 216B magnetized in the S pole may be arranged alternately, and the shape of the protrusions is not limited.
  • the magnetic sensor 70 is arranged so that the plane whose normal is the rotation center line 226 and the magnetic sensing surface of the magnetic sensor 70 are parallel to each other. That is, the magnetic sensing surface of the magnetic sensor 70 is arranged in parallel with the XY plane. By arranging in this way, the magnetic sensor 70 can measure the magnetic field direction of the magnetic field component (in-plane magnetic field component) parallel to the XY plane.
  • the bypass magnetic path forming body 240 which is a characteristic configuration of the present invention, is disposed at a predetermined gap g so as to face the yoke 215A (N pole side yoke) and the yoke 215B (S pole side yoke). Yes. More specifically, the bypass magnetic path forming body 240 is arranged at a predetermined interval g so as to face the side surface of the magnet 211 and the surfaces of the yoke protrusion 216A and the yoke protrusion 216B.
  • the bypass magnetic path forming body 240 forms a magnetic flux path.
  • the bypass magnetic path forming body 240 is also made of a material that allows magnetic flux to pass, and is made of a magnetic material such as a steel plate (iron), permalloy, or mu metal.
  • the bypass magnetic path forming body 240 functions as a bypass magnetic path for eliminating or reducing the influence of the global magnetic field lines 250 from the N pole to the S pole of the magnet 211 on the magnetic sensor 70.
  • the global magnetic field lines 250 from the N pole of the magnet 211 flow toward the S pole of the magnet 211, but pass through the bypass magnetic path forming body 240 in the vicinity of the bypass magnetic path forming body 240. It behaves so as to flow toward the south pole of the magnet 211. Therefore, the global magnetic field lines 250 do not affect the internal space of the bypass magnetic path forming body 240, or the influence is greatly suppressed.
  • the bypass magnetic path forming body 240 has a first surface 240A that extends outward facing the yoke (N pole side yoke) 215A, and extends outward facing the yoke (S pole side yoke) 215B. And a second surface 240B. In the case of the configuration shown in FIG. 3, it has a third surface 240C of magnetic material that connects the first surface 240A and the second surface 240B.
  • the bypass magnetic path forming body 240 of the present invention may have a configuration in which the first surface 240A and the second surface 240B are directly connected, and in that case, the bypass magnetic path forming body 240 does not have the third surface.
  • the cross section of the bypass magnetic path forming body 240 has a shape having an opening 240 ⁇ / b> D that opens toward the magnetic flux generator 202, and exhibits, for example, a “U” shape of katakana characters.
  • the opening 240D has a role for the magnetic sensor 70 to detect a modulation magnetic field by introducing a local modulation magnetic field generated by the yoke protrusions 216A and 216B.
  • both side surfaces of the bypass magnetic path forming body 240 are also opened, and the bypass magnetic path forming body 240 has three sides with the first surface 240A as the upper surface, the second surface 240B as the lower surface, and the third surface 240C as the outer peripheral side surface. The other three sides are open.
  • the bypass magnetic path forming body 240 does not necessarily have a “U” shape. As will be described later, the bypass magnetic path forming body 240 intersects the Z axis direction and the Z direction included in the magnetic flux in the Z axis direction or intersects at a predetermined angle. What is necessary is just to have the function to flow a magnetic flux component.
  • the first surface 240A and the second surface 240B may be directly connected. It has a cross-sectional shape with the Greek letter lambda ( ⁇ ) turned sideways. Further, as shown in FIG. 27 (b), the first surface 240A and the second surface 240B may be connected by a curved magnetic body (third surface). Although not shown, the first surface 240A and the second surface 240B may have a curved surface configuration.
  • the first surface 240A is disposed to face the yoke (N pole side yoke) 215A
  • the second surface 240B is disposed to face the yoke (S pole side yoke) 215B.
  • facing to each other is used in a broad sense that one side is arranged facing each other or one side is arranged close to each other.
  • the thickness Dm of the magnetic flux generator 202 is defined as the length from end to end of the pair of yokes 215A, 215B.
  • the height Hb of the bypass magnetic path forming body 240 is defined as the height of the bypass magnetic path forming body 240 on the magnetic flux generator side (as shown in FIG. 28A).
  • the thickness Dm (Z direction) of the magnetic flux generator 202 and the height Hb of the bypass magnetic path forming body 240 are substantially equal.
  • Dm > Hb.
  • bypass magnetic path action space the space surrounded by the bypass magnetic path forming body 240 and in the vicinity thereof. Therefore, the local modulation magnetic field generated by the yoke protrusions 216A and 216B is detected by the magnetic sensor 70.
  • the “bypass magnetic path working space” is defined as a space in which the strength of the global magnetic field lines 250 in the Z direction is sufficiently weakened by the magnetic field bypass effect of the bypass magnetic path forming body 240. Therefore, it is not necessary to cover all surfaces of this space with the bypass magnetic path forming body 240. It is only necessary that the influence of the global magnetic field lines 250 is weakened by installing the bypass magnetic path forming body 240 as compared with the case where the bypass magnetic path forming body 240 is not provided, and in practice, if the strength is reduced to 50%. Provide.
  • bypass magnetic path inclusion space is defined as a space surrounded by the bypass magnetic path formation body 240 and is also referred to as “internal space” of the bypass magnetic path formation body.
  • the bypass magnetic path inclusion space does not need to be covered with the bypass magnetic path forming body 240 on all surfaces.
  • the bypass magnetic path inclusion space is defined as follows for the U-shaped bypass magnetic path forming body 240.
  • FIG. 29A is a perspective view of the bypass magnetic path forming body 240 of FIG. 3, and FIG. 29B is a top view thereof.
  • the bypass magnetic path forming body 240 of FIG. 29 three surfaces, that is, the first surface 240A, the second surface 240B, and the third surface 240C are made of a magnetic material.
  • the bypass magnetic path forming body has the opening 240D facing the magnetic flux generator 202.
  • a virtual surface connecting the first surface side portion 242A and the second surface side portion 242B is referred to as a side surface opening surface 240E.
  • bypass magnetic path inclusion space is defined as a space surrounded by the following six surfaces: a first surface 240A, a second surface 240B, a third surface 240C, And it is six surfaces of opening part 240D and side opening surface 240E, 240F.
  • the bypass magnetic path inclusion space is defined by five surfaces excluding the third surface. It is clear that the bypass magnetic path inclusion space is similarly defined for the bypass magnetic path forming body 240 having other shapes.
  • bypass magnetic path enclosure space is defined as a sum space (union space) of the bypass magnetic path inclusion space and the space between the bypass magnetic path inclusion space and the magnetic flux generator 202.
  • the bypass magnetic path surrounding space is a union space of the internal space of the bypass magnetic path forming body 240 and the space between the internal space and the magnetic flux generator 202.
  • the union or “union space” of the two spaces A and B has the same meaning as the sum of the set (union set), either one or both of the spaces It means a space belonging to the space.
  • the sum space of the space A and the space B is a space obtained by combining the space A and the space B.
  • the effect of reducing the magnetic field in the Z direction by the bypass magnetic path forming body 240 also acts on the space around the “bypass magnetic path surrounding space”. Therefore, the “bypass magnetic path working space” includes the “bypass magnetic path surrounding space” and its peripheral part.
  • FIG. 4A is a view of the magnetic flux generator 202 and the bypass magnetic path forming body 240 as viewed from above
  • FIG. 4B is a view showing a cross section on the XZ plane.
  • the bypass magnetic path forming body 240 has a U-shaped cross section as described above, and no magnetic material is provided on the side surface of the bypass magnetic path forming body 240 facing the yoke protrusions 216A and 216B. It has a configuration.
  • the bypass magnetic path forming body 240 has a shape obtained by cutting a circular ring at a predetermined angle as seen from FIG. 4A when viewed from above, and the magnetic sensor 70 is disposed in this internal space. Yes.
  • a region A is a region spatially surrounded by the bypass magnetic path forming body 240. Region A is referred to as “bypass magnetic path inclusion space”. The region A is also called an internal space of the bypass magnetic path forming body.
  • Region B is a region between the magnetic flux generator 202 and the region A. What should be noted here is that the thickness of the first surface 240A and the second surface 240B of the bypass magnetic path forming body 240 and the outer peripheral side surface of the magnetic flux generator 202 are shown in the cross-sectional view of FIG. The space area D1 and the space area D2 between the two are not included in the area B.
  • the “bypass magnetic path surrounding space” is defined as the union space of region A and region B. In other words, the bypass magnetic path surrounding space is a space in which the region A (bypass magnetic path inclusion space) and the region B are combined.
  • bypass magnetic path surrounding space is a bypass magnetic path inclusion space (region A) and a space (region B) between the opening 240D of the bypass magnetic path forming body and the magnetic flux generator 240 connected thereto.
  • the bypass magnetic path surrounding space is a sum space of the bypass magnetic path inclusion space (region A) and the region B.
  • the “bypass magnetic path surrounding space” includes the region B includes the region B.
  • the Z-direction component of the magnetic field decreases due to the presence of the bypass magnetic path forming body 240.
  • strong magnetic lines of force extending from the north pole to the south pole of the magnet 211 through the first and second surfaces from the respective yokes 215A and 215B pass through the regions D1 and D2, and the magnetic sensor 70 is passed through the regions D1 and D2.
  • the local modulation magnetic field formed by the yoke protrusions 216A and 216B cannot be detected. Therefore, the regions D1 and D2 are not included in the “bypass magnetic path surrounding space”.
  • bypass magnetic path working space includes
  • the “bypass magnetic path effect space” is defined as a space obtained by combining the areas A, B, C1, and C2.
  • both side surfaces of the bypass magnetic path forming body 240 are open. However, if these both side surfaces are closed with a magnetic material, the region C1 and the region C2 are reduced in the Z-direction magnetic field. Since the effect does not act, the “bypass magnetic path working space” is a space in which the region A and the region B are added.
  • FIG. 5 shows the result of calculating the magnetic field angle at the position where the magnetic sensor 70 is arranged by the magnetic field calculation in the rotation angle measuring device 80 having the configuration shown in FIG. 3 and FIG. FIG. 5 corresponds to FIG. 26, calculates the magnetic field by the finite element method, and quantitatively determines the direction of the horizontal (XY plane) magnetic field at the location of the magnetic sensor 70 when the magnetic flux generator 202 rotates. Asked.
  • the magnetic field angle distribution is almost the same as the solid line in FIG.
  • Deviation from the ideal ideal straight line is about ⁇ 30 °, which is substantially the same characteristic as in the case of FIG. 26 (configuration without the bypass magnetic path forming body 240).
  • the error of ⁇ 30 ° is the same as the magnetic field distortion of the multipolar magnetized magnet, and can be corrected by an appropriate correction method. For this reason, it is possible to measure the rotation angle with high accuracy.
  • a circle indicates a magnetic field distortion error in a conventional configuration without the bypass magnetic path forming body 240.
  • the error reaches 90 °, and when it is shifted by 0.5 mm in the axial direction, the error reaches 180 °. In this manner, the magnetic field distortion error increases dramatically as the axial displacement increases.
  • the mark ⁇ indicates the magnetic field distortion error in the present example in which the bypass magnetic path forming body 240 is provided.
  • the magnetic field distortion error hardly increases even if the installation position of the magnetic sensor 70 is shifted by 0.5 mm in the axial direction.
  • the tolerance of the installation position of the magnetic sensor 70 can be greatly improved by providing the bypass magnetic path forming body 240 as in the present embodiment.
  • FIG. 7 is a graph showing the magnetic field intensity at the installation position of the magnetic sensor 70.
  • the magnetic field B is decomposed into the absolute value
  • the installation position of the magnetic sensor 70 is shifted by 0.4 mm in the axial direction, the XY in-plane component (plotted by a circle) is reduced to 3 mT, and the Z-direction component (plotted by a triangle) is 113 mT, which is the Z direction.
  • the ingredient is 38 times stronger.
  • the Z direction component is due to the globally distributed magnetic force lines 250 generated by the magnet 211, and has almost no magnetic field change component corresponding to the rotation angle.
  • the magnetic field of the XY in-plane component having the rotation angle information is small, the rotation angle measurement error becomes large.
  • the measurement accuracy of the magnetic sensor 70 is normally 10 mT or less, the measurement accuracy deteriorates. Therefore, it can be understood from this point that the measurement accuracy of the rotation angle is deteriorated in the conventional configuration.
  • the Z-direction component of the magnetic field (plotted by ⁇ ) is 8 mT, and the Z-direction component is greatly reduced compared to the case where the bypass magnetic path forming body 240 is not provided.
  • the magnetic field strength of the XY in-plane component Is also getting smaller.
  • including the rotation angle information is larger than the Z direction component
  • the XY in-plane component (plotted with ⁇ ) is 15 mT
  • the Z-direction component (plotted with ⁇ ) is 6.3 mT.
  • a magnetic field direction measuring sensor is used as the magnetic sensor 70, and the magnetic field sensing surface is arranged perpendicular to the Z direction. Therefore, it is difficult to be influenced by the Z direction component of the magnetic field, but there are some that are affected by the type of sensor.
  • Some magnetic field direction measuring sensors use Hall effect elements or magnetoresistive effect elements as magnetic field sensitive elements, but those using Hall effect elements are particularly susceptible to the Z direction component of the magnetic field. For example, in a magnetic field direction measurement sensor that detects the magnetic field direction by measuring the spatial difference in magnetic field strength using a plurality of Hall effect elements, measurement is performed when the magnetic field component perpendicular to the sensor sensing surface is strong. Sensitive to accuracy.
  • the influence of the global magnetic field or the magnetic field lines 250 is weakened by using the bypass magnetic path forming body 240. Therefore, particularly when the magnetic field direction measurement sensor using a plurality of Hall elements is used. The effect is great.
  • a material of the bypass magnetic path forming body 240 basically, a magnetic body (magnetic susceptibility of 10 or more) capable of flowing a magnetic field line may be used. It is desirable to use, specifically iron, silicon steel, permalloy, mu metal, and the like. In this example, plate-like iron was processed into the shape shown in FIGS. 3 and 4 to produce a bypass magnetic path forming body 240.
  • the bypass magnetic path forming body 240 reduces or does not flow a magnetic field in the Z direction or a global magnetic field having a vector component in the Z direction and the horizontal direction to the magnetic sensor 70.
  • the higher the magnetic susceptibility ⁇ the higher the effect.
  • a magnetic material having a magnetic susceptibility ⁇ of 100 or more it is particularly preferable to use a magnetic material having a magnetic susceptibility ⁇ of 100 or more.
  • iron or silicon steel as the magnetic material.
  • a material having a magnetic susceptibility ⁇ of more than 7000 such as permalloy or mu metal is used, the thickness of the bypass magnetic path forming body 240 is reduced. Is more preferable because the same effect can be obtained.
  • this embodiment it is difficult to be affected by a disturbance magnetic field. That is, it is conceivable that the measurement accuracy of the rotation angle deteriorates when a magnetic field from the outside enters the position of the magnetic sensor 70, but the magnetic sensor 70 is covered with the bypass magnetic path forming body 240 as in this embodiment. In addition, it can be expected that the disturbance magnetic field from the outside is shielded by the bypass magnetic path forming body and the measurement accuracy of the rotation angle can be suppressed from deteriorating.
  • the second embodiment is different from the first embodiment in that the yoke protrusions 216A and 216B of the magnetic flux generator 202 are formed in a triangular shape.
  • the shapes of the yoke protrusions 216A and 216B are rectangular. However, if the yoke protrusions 216A and 216B are triangular as in the second embodiment, the XY in-plane component formed at the position of the magnetic sensor 70 is formed. There is an effect that the intensity of (magnetic field) is increased.
  • the reason why the magnetic field intensity of the in-plane component is increased is that the triangular yoke protrusions 216A and 216B are compared to the opposing lengths of the rectangular yoke protrusions 216A and 216B when the distance between the yoke 215A and the yoke 215B is the same. It is considered that the strength of the XY in-plane component (magnetic field) is increased because the length of the opposite faces increases.
  • the use of the triangular yoke protrusions 216A and 216B has the effect that the magnetic field strength of the XY in-plane component formed at the installation position of the magnetic sensor 70 increases.
  • Using triangular yoke protrusions 216A and 216B has the effect of improving measurement accuracy.
  • the shape of the yoke protrusions 216A and 216B is disclosed as a rectangular shape and a triangular shape.
  • the present invention is limited to these two shapes. is not.
  • the magnetic flux generator 202 to which the present invention is applied has a configuration in which a yoke protrusion 216A magnetized in the N pole and a yoke protrusion 216B magnetized in the S pole are arranged adjacent to each other.
  • of the magnetic field at the position where the magnetic sensor 70 is arranged changes as the magnetic flux generator 202 rotates. Therefore, the rotation angle of the magnetic flux generator 202 can be measured by measuring the magnetic field angle.
  • the shape of the yoke protrusions 216A and 216B is not limited as long as the magnetic flux generator 202 targeted by the present invention is configured such that the adjacent yoke protrusions 216A and 216B are alternately magnetized to the north and south poles. Is. Regardless of the shape, the global magnetic field lines 250 formed by the magnet 211 are formed in the Z direction, and the influence of the global magnetic field lines 250 is greatly reduced by the configuration in which the bypass magnetic path forming body 240 is provided. It can be done.
  • the third embodiment is different from the first embodiment in that the bypass magnetic path forming body 240 is not a shape obtained by cutting the circular ring at a predetermined angle as in the first embodiment, but is a rectangular shape when viewed from the upper surface.
  • FIG. 9 is a view of the rotation angle measuring device 80 as viewed from the Z-axis.
  • the bypass magnetic path forming body 240 is a rectangular rectangle, and faces the magnetic flux generator 202 and is close to it.
  • the side surface 240E has a linear shape.
  • the global magnetic field lines 250 formed by the magnet 211 are formed in the Z direction in the same manner as in the first and second embodiments. The influence of the magnetic field lines 250 can be greatly reduced.
  • the bypass magnetic path forming body 240 when the bypass magnetic path forming body 240 is manufactured, the whole is a rectangular rectangle, and the bypass magnetic path forming body 240 is easily processed and manufactured.
  • the bypass magnetic path forming body 240 is not a shape obtained by cutting the circular ring at a predetermined angle as in the first embodiment, but the shape viewed from the upper surface is a substantially rectangular shape, and is opposed to and close to the magnetic flux generator 202.
  • This embodiment differs from the first embodiment in that the opposite side surface is formed in a concave shape.
  • FIGS. 10A and 10B are views of the rotation angle measuring device 80 as viewed from the Z-axis.
  • the bypass magnetic path forming body 240 is a substantially rectangular rectangle, and the magnetic flux Opposite side surfaces facing and close to the generator 202 have a concave contour.
  • the opposing side surface 240 ⁇ / b> F that faces and is close to the magnetic flux generator 202 has an arcuate contour that matches the shape of the side surface of the magnetic flux generator 202.
  • the opposing side surface 240G that faces and is close to the magnetic flux generator 202 has a polygonal contour that matches the shape of the side surface of the magnetic flux generator 202. In this way, the distance (Air Gap length) between the magnetic flux generator 202 and the bypass magnetic path forming body 240 is shortened, so that the global magnetic field lines generated by the magnet 211 of the magnetic flux generator 202 are more effectively bypassed. There is an effect that it can flow to the magnetic path forming body 240.
  • a fifth embodiment of the present invention will be described with reference to FIG.
  • a portion of the bypass magnetic path forming body 240 and a portion of the magnetic flux generator 202 are arranged so as to overlap each other with a gap in the axial direction of the rotation shaft. Is different.
  • the bypass magnetic path forming body 240 uses the bypass magnetic path forming body 240 of Example 3 shown in FIG.
  • FIG. 11A is a view of the rotation angle measuring device 80 as viewed from the Z-axis
  • FIG. 11B is a view showing an XZ cross section.
  • the fifth embodiment is characterized in that the thickness of the portion of the bypass magnetic path forming body 240 facing the magnetic flux generator 202 in the “bypass magnetic path surrounding space” is larger than the thickness of the magnetic flux generator 202. .
  • the first surface 240A of the bypass magnetic path forming body 240 is positioned above the yoke 215A of the magnetic flux generator 202 in the axial direction of the rotation axis.
  • the two surfaces 240B are arranged so as to overlap each other.
  • the magnetic flux generator 202 and the bypass magnetic path forming body 240 are arranged so as to overlap each other, the degree of the entry of the global magnetic field lines 205 from the Z-axis direction is smaller than in the first embodiment, and the measurement is further performed.
  • the configuration can improve the accuracy.
  • the degree of overlap between the bypass magnetic path forming body 240 and the yokes 215A and 215B is such that at least the two corners of the bypass magnetic path forming body 240 extend to a position overlapping the outer peripheral edge of the yoke 215A and 215B.
  • the both end corners of the bypass magnetic path forming body 240 are configured to extend beyond the outer peripheral edges of the yokes 215A and 215B.
  • bypass magnetic path forming body 240 uses the bypass magnetic path forming body 240 of the third embodiment shown in FIG.
  • the bypass magnetic path forming body 240 is characterized by forming an opening 246 in the third surface 240C. With such a configuration, the magnetic sensor 70 can be easily installed.
  • the magnetic sensor 70 is introduced into the “bypass magnetic path surrounding space” of the bypass magnetic path forming body 240 through the opening 246, or conversely, the magnetic sensor 70 is moved from the opening 240 D on the opposite side of the opening 246 to “ Or can be introduced into a “bypass magnetic path enclosure space”.
  • the opening 246 serves as a lead-out port for the signal wiring of the magnetic sensor 70.
  • the magnetic sensor 70 can be easily introduced by providing the opening 246, or can be used as a signal wiring outlet of the magnetic sensor 70.
  • bypass magnetic path forming body 240 is a magnetic body, the reluctance (magnetic reluctance) is small, and the magnetic flux passes more easily than in the air. Therefore, when a part of the bypass magnetic path forming body 240 is the opening 246, the magnetic flux in the bypass magnetic path forming body 240 flows while avoiding the opening 246. Therefore, even if an opening is provided in a part of the bypass magnetic path forming body 240, the effect of bypassing the magnetic flux can be obtained.
  • FIG. 12 shows an example in which the opening 246 is provided on one of the constituent surfaces of the bypass magnetic path forming body 240, here, the third surface 240C, the openings 246 may be provided on a plurality of constituent surfaces.
  • FIG. 13 shows a modification of the sixth embodiment.
  • an opening 246 is formed on the second surface 240B (lower surface) of the bypass magnetic path forming body 240.
  • the magnetic sensor 70 is inserted from the opening 240D of the bypass magnetic path forming body 240 and installed in the “bypass magnetic path surrounding space” or “bypass magnetic path enclosing space”. It is pulled out from the opening 246 which becomes.
  • the third surface 240C of the bypass magnetic path forming body 240 may not be provided with a lead opening, or the rotation angle. This is an effective configuration when the place where the measuring device is attached is restricted, for example, when a lead wire needs to be drawn out in the axial direction when it is provided in an electric motor as shown in FIG.
  • the magnetic sensor 70 is also surrounded by a synthetic resin in a liquid-tight manner, and is installed at a connection portion between the “bypass magnetic path inclusion space” or “bypass magnetic path inclusion space” of the bypass magnetic path forming body and the region B shown in FIG.
  • the seventh embodiment is different from the first embodiment in that the bypass magnetic path forming body 240 is divided with the installation position of the magnetic sensor 70 as a boundary.
  • a space between the divided two bypass magnetic path forming bodies 240-1 and 240-2 is defined as “magnetic path separation space”, and a distance between the two bypass magnetic paths is defined as “magnetic path separation length”. Define. Further, the expected angle when the magnetic path separation length is viewed from the rotation center line 226 is defined as “magnetic path separation angle”. In other words, the “magnetic path separation angle” is an angle formed by two straight lines formed by connecting the rotation center line 226 and both ends of the “magnetic path separation space”.
  • the magnetic path separation space is formed substantially along the Z direction (axial direction), and each of the divided bypass magnetic path forming bodies 240-1 and 240-2 is the N pole of the magnet 211. Is divided so as to form a magnetic path connected to the S pole.
  • the reluctance (magnetic resistance) of the magnetic path that is, the difficulty of passing the magnetic flux increases.
  • the function of bypassing unnecessary magnetic fluxes from to the south pole will not be performed.
  • Example 7 since the magnetic path from the N pole to the S pole is maintained, the effect of bypassing the magnetic flux is maintained.
  • the “magnetic path separation space” may be substantially along the Z direction (axial direction), and may be formed in a slightly oblique direction with respect to the Z direction.
  • the degree of inclination should be determined within an allowable range according to the specifications for which the system is built.
  • the “magnetic path separation space” defined in the seventh embodiment is included in the definition of the “bypass magnetic path action space” described above. This is because the Z-direction component of the magnetic field is sufficiently reduced by the action of the magnetic path magnetic path forming bodies 240-1 and 240-2. For this reason, when the magnetic sensor 70 is arranged in the “magnetic path separation space”, the effects of the present invention, that is, the tolerance of the installation position of the magnetic sensor 70 can be increased and the measurement accuracy can be improved.
  • an object of the present invention is to reduce a magnetic field component in the Z direction that does not include rotation angle information. Therefore, the degree of effect can be known by examining the magnitude
  • of the Z direction component at the measurement position P ( ⁇ ) on the dotted line is obtained by magnetic field calculation. It was.
  • the measurement position P ( ⁇ ) is a position away from the X axis by an angle ⁇ . This time, the magnitude
  • the magnetic path separation angle ⁇ is set to 5 °, 10 °, 20 °, and 30 °. In each case, magnetic field calculation was performed.
  • FIG. 16 shows the value of the magnitude
  • of the Z direction component is about 10 mT.
  • is at a low level that is almost the same as that in the internal space of the bypass magnetic path forming bodies 240-1 and 240-2. It can also be seen that the magnitude
  • of the Z direction component is sufficiently small even at the magnetic path separation angle ⁇ 10 °. On the other hand, as the magnetic path separation angle ⁇ increases, the magnitude
  • the “magnetic path separation space” it can be understood that there is a magnetic flux reduction effect by the bypass magnetic path forming bodies 240-1 and 240-2. Further, as can be seen from FIG. 16, when the magnetic path separation angle ⁇ is set to 10 degrees or less, a higher effect can be obtained, and a more preferable result can be obtained.
  • the effect of the configuration of the seventh embodiment has an effect that it is easy to install the magnetic sensor 70 in addition to the common effect that the installation tolerance of the magnetic sensor 70 is improved and the measurement accuracy of the rotation angle is improved.
  • the magnetic sensor 70 may be installed in the magnetic path separation space, so that the magnetic sensor 70 is installed inside the bypass magnetic path forming bodies 240-1 and 240-2, or the signal wiring of the magnetic sensor 70 is pulled out. This is because it becomes easier.
  • the eighth embodiment is different from the first embodiment in that a plurality of magnetic sensors 70, two here, are installed.
  • the reliability of the rotation angle measuring device 80 can be improved by adopting a redundant system configuration with two magnetic sensors 70-1 and 70-2. This reliability is not the reliability related to the measurement accuracy possessed by the magnetic sensor 70 itself, but means the reliability with respect to failures and abnormalities.
  • the configuration shown in FIG. 17 can be adopted. became.
  • the magnetic sensors 70-1 and 70-2 are arranged on both sides of the printed circuit board 161 with a space therebetween.
  • the magnetic sensors 70-1 and 70-2 are bonded to the printed circuit board 161. It is fixed by the method.
  • the ninth embodiment is different from the first embodiment in that a magnetic flux generator 202 having triangular yoke protrusions 216A and 216B and two magnetic sensors 70-1 and 70-2 are used.
  • the configuration of the redundant system shown in the eighth embodiment can be adopted.
  • another function and effect described below is made by using the characteristics of the triangular yoke protrusions 216A and 216B. Can be obtained.
  • the installation of the printed circuit board 161 is performed.
  • the rotation hardly affected by the position fluctuation of the printed circuit board 161 is achieved.
  • the angle measuring device 80 can be obtained.
  • rotary machine here is not limited to an electric motor or a generator, but is a concept including a machine including a rotary element such as a rotary shaft.
  • FIG. 19 shows a cross section of a rotating machine according to the tenth embodiment.
  • the tenth embodiment is an electric motor, and includes an electric motor unit 100 and a rotation angle detecting unit 200.
  • the electric motor unit 100 generates rotational torque by rotating a plurality of rotating magnetic poles by a magnetic action of a plurality of fixed magnetic poles and a plurality of rotating magnetic poles, and includes a stator 110 and a plurality of stators constituting the plurality of fixed magnetic poles. It is comprised from the rotor 120 which comprises this rotating magnetic pole.
  • the stator 110 includes a stator core 111 and a stator coil 112 attached to the stator core 111.
  • the rotor 120 is disposed to face the inner peripheral side of the stator 110 via a gap and is rotatably supported.
  • a three-phase AC permanent magnet synchronous motor is used as the motor.
  • the casing surrounding the motor body is composed of a cylindrical frame 101 and first and second brackets 102 and 103 provided at both ends of the frame 101 in the axial direction.
  • a bearing 106 is provided at the center of the first bracket 101, and a bearing 107 is provided at the center of the second bracket 103. These bearings 106 and 107 support the rotary shaft 121 so as to be rotatable. Yes.
  • a seal member (not shown) is provided between the frame 101 and the first bracket 102, and this seal member is an O-ring provided in an annular shape by the frame 101 and the first bracket 102 in the axial direction and the radial direction. It is sandwiched between and compressed. Thereby, between the flame
  • the stator 110 includes a stator core 111 and a stator coil 112 attached to the stator core 111, and is installed on the inner peripheral surface of the frame 101.
  • the stator core 111 is a magnetic body (magnetic path forming body) formed by laminating a plurality of silicon steel plates in the axial direction.
  • the stator core 111 protrudes inward in the radial direction from the annular back core and the inner peripheral portion of the back core. It is comprised from the several teeth arrange
  • a winding conductor constituting the stator coil 112 is intensively wound around each of the plurality of teeth.
  • the plurality of winding conductors are electrically connected for each phase by a connecting member juxtaposed at the axial end of one coil end (second bracket 103 side) of the stator coil 112, and further as a three-phase winding. Electrically connected.
  • Three-phase winding connection methods include a ⁇ (delta) connection method and a Y (star) connection method. In this embodiment, a ⁇ (delta) connection method is adopted.
  • the rotor 120 includes a rotor core fixed on the outer peripheral surface of the rotating shaft 121 and a magnet (the rotor core and the magnet are not shown).
  • a magnet the rotor core and the magnet are not shown.
  • the surface magnet type permanent magnet motor a plurality of magnets are arranged on the surface of the rotor core.
  • the embedded magnet type permanent magnet motor the magnet is embedded in the rotor core.
  • the rotation angle detection unit 200 includes a magnetic sensor 70, a magnetic flux generator 202, and a bypass magnetic path forming body 240.
  • the magnetic flux generator 202 rotates along the rotation center line 226 in conjunction with the rotation of the rotating shaft 121 of the rotating machine.
  • the magnetic flux generator 202 is attached to the rotating shaft 121 of the rotating machine.
  • the present invention is not limited to this configuration, and the rotating shaft 121 of the rotating machine and the rotating shaft on which the magnetic flux generator 202 is installed are separate shafts, and both shafts are connected by gears or the like. May be rotated.
  • the rotation center line of the rotating shaft 121 of the rotating machine and the rotation center line of the magnetic flux generator may be made different from each other by changing the rotation direction using a gear or the like.
  • the configuration of the magnetic flux generator 202 is the same as that shown in FIG. That is, it is composed of a dipole magnet 211 magnetized in the direction of the rotation center line 226 and the two yokes 215A and 215B.
  • the yokes 215A and 215B have comb-shaped yoke protrusions 216A and 216B, respectively.
  • the yokes 215A and 215B and the yoke protrusions 216A and 216B constituting the magnetic flux generator 202 are not shown.
  • the bypass magnetic path forming body 240 is made of a magnetic material having a magnetic susceptibility of 10 or more, and a silicon steel plate having a thickness of 1 mm is used in this embodiment.
  • the structure of the bypass magnetic path forming body 240 is the same as that shown in FIG.
  • the bypass magnetic path forming body 240 was fixed to the second bracket 103 using the fixing tool 132.
  • the magnetic sensor 70 was installed in the “bypass magnetic path working space” of the bypass magnetic path forming body 240, but more specifically, the magnetic sensor 70 was installed in the “bypass magnetic path surrounding space”.
  • a magnetic field direction measuring sensor was used as the magnetic sensor 70, and the magnetic field sensing surface was arranged so as to be parallel to a plane having the rotation center line 226 as a normal line.
  • the magnetic sensor 70 detects the modulation magnetic field generated by the yoke protrusions 216A and 216B at a position where the measurement accuracy is best in terms of design.
  • the bypass magnetic path forming body 240 suppresses a decrease in measurement accuracy due to this deviation.
  • a local modulation magnetic field generated by the yoke protrusions 216 ⁇ / b> A and 216 ⁇ / b> B of the magnetic flux generator 202 can be detected, and the magnetic field angle linked to the rotation angle of the rotating shaft 121 can be measured by the magnetic sensor 70. It becomes like this.
  • the reproducibility between sectors of the magnetic field angle distribution is dominated by the mechanical accuracy of the yoke protrusions 216A and 216B, so the reproducibility between sectors is high. Therefore, the rotation angle of the rotation shaft 121 can be accurately measured from the measured magnetic field angle.
  • the rotation angle signal thus measured is input to a control device (electronic control unit, Electronic Control Unit).
  • the control device can appropriately control the electric motor by outputting the drive voltage waveform of the electric motor using the information on the rotation angle.
  • the eleventh embodiment is different from the tenth embodiment in that a part of the bracket constituting the electric motor is used as a part of the constituent elements of the bypass magnetic path forming body 240.
  • This Example 11 is characterized in that some of the constituent elements of the electric motor are shared as constituent elements of the bypass magnetic path forming body 240.
  • the bypass magnetic path forming body 240 is installed in the second bracket 103 of the electric motor, but the second surface 240B of the bypass magnetic path forming body 240 shown in FIG. ing. If comprised in this way, the structure of the bypass magnetic path formation body 240 will be simplified, and there exists an effect which manufacture becomes easy from the ease of incorporating the magnetic sensor 70, etc.
  • the second bracket 103 is usually made of an iron-based material, there is no problem because the magnetic material has a sufficient magnetic susceptibility.
  • the 2nd surface 240B is shared with the 2nd bracket 103
  • this description does not prescribe
  • the second surface 240B of the bypass magnetic path forming body 240 is configured using the surface of the second bracket 103.
  • the magnetic field lines in the Z direction adversely affect the magnetic sensor 70. Can be suppressed.
  • the magnetic reluctance increases and the effect of reducing the bypass of the magnetic field lines in the Z direction may decrease.
  • the body 240 and the second bracket 103 need to be configured so as to be in close contact with each other. In the present embodiment, the two are closely adhered and fixed, but an increase in magnetic reluctance can be taken by bringing them into close contact via a soft resin or the like that allows magnetic flux to pass through.
  • the twelfth embodiment shows the configuration of the torque measuring device (torque sensor).
  • the torque measuring device includes an input shaft 131 and an output shaft 132 connected by a torsion bar 135, and a rotation angle measuring device 80 installed on each of the input shaft 131 and the output shaft 132. is there.
  • the input shaft 131 and the output shaft 132 are connected by a torsion bar 135.
  • the torque M is measured from ⁇ .
  • Such a torque measuring device is used in a steering device or the like that transmits the movement of a steering wheel of an automobile to wheels.
  • the input shaft 131 is provided with a first magnetic flux generator 202-1 and the output shaft 132 is provided with a second magnetic flux generator 202-2.
  • the two magnetic flux generators 202-1 and 202-2 are each composed of a magnet 211 and two yokes 215A and 215B.
  • bypass magnetic path forming bodies 240-1, 240-2 and magnetic sensors 70-1, 70-2 are arranged on the respective side surfaces of the magnetic flux generators 202-1 and 202-2.
  • the magnetic sensors 70-1 and 70-2 are disposed in the “bypass magnetic path action space” of the bypass magnetic path forming bodies 240-1 and 240-2, respectively.
  • Magnetic sensors 70-1 and 70-2 are arranged in the “bypass magnetic path surrounding space” of the body 240.
  • the bypass magnetic path forming bodies 240-1 and 240-2 are fixed to a mounting housing (not shown).
  • the attachment housing may be a dedicated attachment of the bypass magnetic path forming body 240, or the bypass magnetic path forming body 240 may be attached to a component constituting another steering device.
  • the magnetic sensors 70-1 and 70-2 are arranged in the “bypass magnetic path action space” of the bypass magnetic path forming body 240, the magnetic flux generators 202-1 and 202-2 are generated. Since the magnetic field component in the Z direction is bypassed by the bypass magnetic path forming body 240, the rotation angles ⁇ 1 and ⁇ 2 can be measured with high accuracy. The reason for this is as described above.
  • the angle difference ⁇ is designed to be about 4 ° at the maximum torque, so it is necessary to measure the angle difference between -4 ° and + 4 ° with high accuracy.
  • the angle difference can be easily calculated.
  • the torque M can be measured by multiplying the rotation angle difference ⁇ by an appropriate proportional coefficient. Such calculation is executed by a control device having a separately provided arithmetic function.
  • Rotational angle measurement unit may be provided in the torque measurement device as necessary. For example, when used in an electric power steering apparatus, it may be desired to measure the rotation angle of the input shaft 131 in addition to torque measurement. In the case of an electric power steering device, the rotation angle of the input shaft 131 corresponds to a steering angle corresponding to the angle of the steering wheel.
  • the rotation angle measurement unit is not an essential component in the torque measurement device, but is required in the electric power steering device.
  • the sensor magnet 143 is installed on the input shaft 131, and the sensor magnet 143 is a dipole magnet magnetized in the radial direction.
  • a magnetic sensor 142 is disposed on the side surface of the sensor magnet 143.
  • the magnetic sensor 142 is a magnetic field direction measurement sensor and is fixed to a housing (not shown). Since the sensor magnet 143 is a dipole magnet, the magnetic field angle measured by the magnetic sensor 142 corresponds to one rotation corresponding to one rotation of the input shaft. By appropriately correcting the magnetic field angle measured by the magnetic sensor 142, the rotation angle of the input shaft 131 can be measured.
  • the thirteenth embodiment shows a configuration of an electric power steering system (Electric Power-Assisted Steeling system).
  • the steering shaft 503 mechanically coupled to the handle 501 is connected to the coupling portion 504 via the torque sensor 502.
  • a rotating shaft 121 of the electric motor 100 is connected to a connecting portion 504 constituted by a reduction gear or the like, and a connecting shaft 505 is further connected to the connecting portion 504.
  • the connecting shaft 505 is connected to the gear box 506, and the tie rod 507 is connected to the gear box 506.
  • the gear box 506 converts the rotational movement of the connecting shaft 505 into the linear movement of the tie rod 507, and tires (not shown) are arranged at both ends of the tie rod 507, and the tires according to the linear movement of the tie rods. The direction will be changed.
  • Such an electric steering system has a well-known structure.
  • the rotating body 121 is a rotating shaft of the electric motor 100, and a magnetic flux generator 202 is installed at one end.
  • a magnetic sensor 70 and a bypass magnetic path forming body 240 are installed in the vicinity of the magnetic flux generator 202, and the rotation angle of the rotating body 121 is measured and the rotation angle information is transmitted to the ECU 411.
  • the magnetic flux generator 202, the magnetic sensor 70, and the bypass magnetic path forming body 240 constitute a rotation angle measuring device 80.
  • the configuration and operation of the rotation angle measuring device 80 are as described above.
  • the configuration of the magnetic flux generator 202 is the same as that of the magnetic flux generator 202 shown in FIGS. 3 and 4, and is composed of yokes 215A and 215b having yoke protrusions 216A and 216b, and a magnet 211. Further, the bypass magnetic path forming body 240 is also configured as shown in FIGS.
  • the rotational operation is detected by the torque sensor 502 and transmitted to the ECU 411 as an electrical signal.
  • the ECU 411 calculates an appropriate motor drive amount from the signal from the torque sensor 502, the rotation angle signal ⁇ from the rotation angle measuring device 80, the vehicle speed signal, and the like, and transmits the signal to the motor drive unit 412. Accordingly, the electric motor 100 rotationally drives the rotating body 121 to assist (assist) the rotation of the connecting shaft 505. In this way, the exercise of changing the direction of the tire is assisted.
  • the magnetic sensor 70 in the rotation angle measuring device 80 is disposed in the “bypass magnetic path action space” of the bypass magnetic path forming body 240, the magnetic field in the Z direction is bypassed with high accuracy.
  • the rotation angle can be measured.
  • the fourteenth embodiment shows the configuration of an electric vehicle drive device.
  • FIG. 23 shows an electric vehicle drive device for a hybrid vehicle in which an internal combustion engine and an electric motor are combined as the power of the vehicle.
  • the output rotation shaft of the internal combustion engine 553, the generator 552, and the driving electric motor 551 are arranged on the same axis, and the power is appropriately transmitted by the function of the power distribution mechanism 554.
  • the method of power distribution is appropriately set based on information such as the running state of the vehicle, the acceleration state, and the battery charging state. Further, a power coupling mechanism 557 for transmitting power from the power distribution mechanism 554 to the power shaft 558 is provided.
  • the rotation angle measuring unit 200 includes a magnetic flux generator 202-1, a magnetic sensor 70-1, and a bypass magnetic path forming body 240-1.
  • the configuration of the magnetic flux generator 202-1 is the same as that of the magnetic flux generator shown in FIGS. 3 and 4, and is composed of yokes 215A and 215B having yoke protrusions 216A and 216B, and a magnet 211. Further, the bypass magnetic path forming body 240 is also configured as shown in FIGS.
  • the generator 552 is also provided with a rotation angle detection unit, and this rotation angle measurement unit includes a magnetic flux generator 202-2, a magnetic sensor 70-2, and a bypass magnetic path forming body 240-2.
  • This configuration is the same as that of the magnetic flux generator 202-1.
  • the magnetic sensor 70 in the rotation angle measuring device 8080 of the driving electric motor 551 and the generator 552 is disposed in the “bypass magnetic path working space” of the bypass magnetic path forming body 240. Therefore, the rotation angle can be measured with high accuracy by bypassing the magnetic field in the Z direction.
  • the number Np1 of the magnetic poles of the yoke protrusions 216A and 216B of the magnetic flux generator 202-1 preferably corresponds to the number of magnetic poles (p ⁇ 2) of the drive motor 551.
  • the number of magnetic poles of the drive motor is (p ⁇ 2). )
  • the magnetic field angle signals output from the magnetic sensors 70-1 and 70-2 have a cycle corresponding to the electrical angle of the drive motor 551, so that the drive motor can be easily controlled.
  • the relationship between the number Np of magnetic poles of the yoke protrusions 216A and 216B of the magnetic flux generator 202-2 and the number of magnetic poles of the generator 552 is the same.
  • the number of poles of the electric motor may be increased in order to obtain a high output torque.
  • the magnetic flux generator 202 used in the rotation measuring device described in the present invention the yoke protrusions 216A and 216B are used.
  • the number of poles of the magnetic flux generator can be easily increased by increasing the number of magnetic flux generators, which is suitable for use in such an electric vehicle drive device.
  • Bypass magnet Path forming body 240A: first surface of bypass magnetic path forming body, 240B: second surface of bypass magnetic path forming body, 240C: third surface of bypass magnetic path forming body, 240D: opening of bypass magnetic path forming body 246: opening, 250: magnetic field line, 411: electronic control unit, 412: drive unit, 501: handle, 502 ... torque sensor 503: Steering shaft, 504 ... Connecting portion, 505 ... Connecting shaft, 506 ... Gear box, 507 ... Tie rod, 551 ... Drive motor, 552 ... Generator, 553 ... Internal combustion engine, 554 ... Power distribution mechanism, 557 ... Power coupling Mechanism, 558 ... Power shaft.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Transmission And Conversion Of Sensor Element Output (AREA)
  • Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
PCT/JP2013/052303 2012-03-27 2013-02-01 回転角計測装置及びこの回転角計測装置を備えた回転機械 WO2013145851A1 (ja)

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JP5427842B2 (ja) 2011-06-30 2014-02-26 日立オートモティブシステムズ株式会社 回転角計測装置，制御装置およびそれらを用いた回転機システム
CN103512482B (zh) * 2013-10-14 2016-01-06 中国科学院电工研究所 一种超导磁悬浮转子姿态测量信号标定装置
JP2015132496A (ja) * 2014-01-10 2015-07-23 セイコーエプソン株式会社 磁気式エンコーダー、電気機械装置、移動体およびロボット
JP6691500B2 (ja) 2017-03-31 2020-04-28 株式会社Ｓｏｋｅｎ トルク検出装置
JP7021957B2 (ja) * 2018-01-11 2022-02-17 日立Astemo株式会社 トルクセンサ
CN111505545B (zh) 2020-04-30 2022-02-18 江苏多维科技有限公司 一种机电调制磁阻旋转式磁场强探头
JP7544105B2 (ja) 2021-10-22 2024-09-03 株式会社デンソー トルク検出システム
JP7545439B2 (ja) 2022-05-09 2024-09-04 Tdk株式会社 回転角度検出装置及び電気制御装置

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