JP6107589B2 - Rotation angle sensor - Google Patents

Description

  The present invention provides a rotation angle for detecting a rotation angle of a rotating body in which the first magnetic pole portions and the second magnetic pole portions having the same lateral width in the rotation direction are alternately connected along the rotation direction and the outer surface forms a circle. It relates to sensors.

  Conventionally, for example, as shown in Patent Document 1, a magnetic member in which N poles and S poles are alternately arranged, and one or more pairs of vector detection type magnetoresistive effect elements facing the magnetic pole arrangement surface of the magnetic member, Have been proposed. One or a plurality of pairs of vector detection type magnetoresistive elements are arranged in a line substantially perpendicular to the magnetic pole arrangement direction of the magnetic member. With this arrangement, the phases of the magnetic fluxes transmitted through all the vector detection type magnetoresistance effect elements are the same.

JP 2006-23179 A

  In the magnetic position detection device described in Patent Document 1 described above, one or a plurality of pairs of vector detection type magnetoresistive elements are arranged in a line substantially perpendicular to the magnetic pole arrangement direction. Therefore, the phases of magnetic fluxes that pass through all the vector detection type magnetoresistive elements are the same. However, in the case of this configuration, since the facing distance between each vector detection type magnetoresistive effect element and the magnetic member is different, the intensity of the magnetic flux passing through each vector detection type magnetoresistive effect element is different. In order to solve this problem, a configuration in which one or more pairs of vector detection type magnetoresistive effect elements are arranged in one row in the magnetic pole arrangement direction is also conceivable. However, in the case of this arrangement, the phases of the magnetic fluxes transmitted through all the vector detection type magnetoresistive elements are different.

  As described above, in any of the above two arrangements, both the strength and direction of the magnetic flux transmitted through each vector detection type magnetoresistance effect element cannot be made the same. Therefore, it has been difficult to detect the rotation state of the magnetic member (rotating body) with high accuracy based on the electrical signal that depends on the resistance value of each vector detection type magnetoresistive element.

  In view of the above problems, an object of the present invention is to provide a rotation angle sensor with improved detection accuracy of the rotation state of a rotating body.

  In order to achieve the above-described object, according to the present invention, the first magnetic pole part (210) and the second magnetic pole part (220) having the same lateral width in the rotational direction are alternately connected along the rotational direction. A rotation angle sensor for detecting a rotation angle of a rotating body (200) having a circular side surface, a free layer whose magnetization direction changes according to a rotating magnetic field generated from the rotating body, and a pin having a fixed magnetization direction A plurality of magnetoresistive elements having a layer and a nonmagnetic intermediate layer provided between the pinned layer and the free layer, the resistance value of which varies according to the magnetization directions of the pinned layer and the free layer ( 11 to 14, 21 to 24), and the plurality of magnetoresistive elements are arranged along the rotation direction so that the distance from the outer surface of the rotating body is constant, and the plurality of magnetic elements The magnetization direction of the pinned layer of each resistive effect element depends on the rotation of the rotating body. A distance β between one reference line (BL) extending from the center (RC) so as to be orthogonal to the rotation direction and the magnetoresistive effect element along the rotation direction, and a pair of first magnetic pole portions adjacent in the rotation direction And the length α of the total width of each of the second magnetic pole portions.

  Thus, according to this invention, the several magnetoresistive effect element (11-14, 21-24) is arrange | positioned along with the rotation direction. According to this, unlike the configuration in which the plurality of magnetoresistive elements are arranged side by side in the direction along the reference line (BL) perpendicular to the rotational direction instead of the rotational direction, the plurality of magnetoresistive elements ( 11-14 and 21-24), the intensity of the magnetic flux passing through is the same. However, in the case of this arrangement, the phases of magnetic fluxes transmitted through the plurality of magnetoresistance effect elements (11-14, 21-24) are different. In other words, a magnetic flux (hereinafter referred to as a reference magnetic flux (BM)) that passes through the intersection of the reference line (BL) and the rotational direction in which the magnetoresistive elements (11-14, 21-24) are arranged, and a reference line ( BL) is out of phase with the magnetic flux passing through a position away from the rotation direction in BL. Therefore, the magnetization direction of the free layer of each magnetoresistive element (11-14, 21-24) is different from the case where it is located on the reference line (BL).

  However, the phase deviation from the reference magnetic flux (BM) described above is the sum of the length α of the lateral widths of the first magnetic pole part (210) and the second magnetic pole part (220) and the reference line along the rotation direction. It is determined by the separation distance β between (BL) and the magnetoresistive effect elements (11-14, 21-24). Therefore, in the present invention, the magnetization directions of the pinned layers of the plurality of magnetoresistive elements (11-14, 21-24) are determined by the separation distance β and the length α, so that the plurality of magnetoresistive elements (11 ˜14, 21 to 24) are prevented from shifting in phase with the reference magnetic flux (BM). As a result, the strength of the magnetic flux passing through the plurality of magnetoresistive elements (11 to 14, 21 to 24) becomes the same, and the phase shift is eliminated. The detection accuracy of the rotational state of the rotating body (200) is improved by using the electrical signals that depend on the resistance values of the plurality of magnetoresistive elements (11-14, 21-24).

  As described above, in the rotating body (200), the first magnetic pole part (210) and the second magnetic pole part (220) having the same lateral width in the rotation direction are alternately connected, and the outer surface forms a circular shape. ing. Therefore, the unit rotation amount of the rotating body (200) can be expressed as 360 ° / α. Further, the reference line (BL) and the magnetoresistive effect elements (11-14, 21-24) are separated by a separation distance β. Therefore, the magnetic flux passing through the magnetoresistive effect elements (11 to 14, 21 to 24) is obtained by multiplying the reference magnetic flux (BM) by a unit rotation amount 360 ° / α by a separation distance β (360 ° / α) × β. Become. As described above, if the magnetization direction of the pinned layer of the plurality of magnetoresistive elements (11-14, 21-24) is rotated by (360 ° / α) × β, the plurality of magnetoresistive elements (11-14, 21 to 24) are regarded as transmitting the reference magnetic flux (BM). Thereby, the phase shift of the several magnetoresistive effect element (11-14, 21-24) is suppressed.

  The elements described in the claims and the means for solving the problems are labeled with parentheses, and the parenthesized numerals are connected to each component described in the embodiment. The elements described in the embodiments themselves are not necessarily shown. The description of the reference numerals with parentheses does not unnecessarily narrow the scope of the claims.

It is a top view which shows the position of the rotation angle sensor which concerns on 1st Embodiment, and a rotary body. It is an enlarged top view which expands and shows the position of a rotation angle sensor and a rotary body. It is a circuit diagram which shows the bridge circuit assembled by the magnetoresistive effect element. It is a timing chart which shows a midpoint potential and a pulse signal. It is a schematic diagram which shows the magnetization direction of a pin layer. It is a schematic diagram which shows the magnetization direction of a free layer. It is a schematic diagram which shows the magnetization direction of a pin layer and a free layer. It is a schematic diagram which shows the magnetization direction of the pinned layer of a comparison structure. It is a schematic diagram which shows the magnetization direction of the pinned layer and free layer of a comparison structure. It is an enlarged top view which shows the modification of a rotation angle sensor. It is a schematic diagram which shows the magnetization direction of the pin layer defined in the case of the reference line shown in FIG. It is an enlarged top view which shows the modification of arrangement | positioning of a magnetoresistive effect element. It is an enlarged top view which shows the modification of the number of magnetoresistive elements. It is a circuit diagram which shows a 1st full bridge circuit. It is a circuit diagram which shows a 2nd full bridge circuit. It is a top view which shows the modification of the position of a rotation angle sensor and a rotary body. It is a top view which shows the modification of the position of a rotation angle sensor and a rotary body.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
The rotation angle sensor according to the present embodiment will be described with reference to FIGS. In FIG. 5, the center CP is indicated by a cross, but in FIGS. 6 to 9, the center CP is omitted in order to simplify the drawing. 6, 7, and 9, the reference magnetic flux BM that passes through the first magnetoresistive effect element 11 is indicated by a solid line arrow, and other magnetoresistive effect elements 12, 21, The magnetic flux passing through each of the lines 22 is indicated by a solid line arrow, and the reference magnetic flux BM is indicated by a one-dot chain line arrow.

  In the following, a plane at the same height position where the rotator 200 and the rotation angle sensor 100 are arranged is a specified plane, and a direction perpendicular to the specified plane and passing through the rotation center RC of the rotator 200 is referred to as an axial direction. In addition, a direction around the axial direction is indicated as a rotation direction (curved arrow shown in FIG. 1), and a direction extending from the rotation center RC along the specified plane is indicated as a radial direction.

  The rotation angle sensor 100 detects the rotation state of the rotating body 200 based on a change in the rotating magnetic field whose direction periodically changes as the rotating body 200 rotates. As shown in FIG. 1, the rotating body 200 is formed by alternately connecting the first magnetic pole portions 210 and the second magnetic pole portions 220 along the rotation direction, and the outer surface thereof has a circular shape. The first magnetic pole part 210 and the second magnetic pole part 220 have the same lateral width in the rotational direction, and the respective outer surfaces viewed from the radial direction are rectangular. Since the first magnetic pole part 210 has an N pole and the second magnetic pole part 220 has an S pole, a magnetic flux flows from the first magnetic pole part 210 to the second magnetic pole part 220. The magnetic flux flowing between the adjacent magnetic pole portions 210 and 220 flows so as to draw a semicircular locus. The rotation angle sensor 100 detects a periodic change caused by rotation of a rotating magnetic field that draws a semicircular locus. The rotating body 200 rotates in the counterclockwise direction and rotates in the clockwise direction.

  The rotation angle sensor 100 includes a magnetoelectric conversion unit 10 or 20 that converts a change in the direction of magnetic flux into an electric signal, and a calculation unit 50 that calculates the rotation angle of the rotating body 200 based on the output signals of the magnetoelectric conversion units 10 and 20. And having. The 1st magnetoelectric conversion part 10 has the magnetoresistive effect elements 11 and 12 which make a pair, and the 2nd magnetoelectric conversion part 20 has the magnetoresistive effect elements 21 and 22 which make a pair. As shown in FIGS. 1 and 2, each of the magnetoresistive effect elements 11, 12, 21, and 22 is arranged side by side along the rotation direction so that the distance from the outer surface of the rotating body 200 is constant. Yes. The first magnetoresistance effect element 11 is located on a reference line BL (a line indicated by a one-dot chain line in FIGS. 1 and 2) extending in the radial direction from the center of rotation RC, and the other magnetoresistance effect elements 12, 21, 22 Each is separated from the reference line BL by a predetermined distance along the rotation direction. More specifically, the second magnetoresistance effect element 12 is separated from the reference line BL by a distance β1, the third magnetoresistance effect element 21 is separated from the reference line BL by a distance β2, and the fourth magnetoresistance effect element 22 is separated from the reference line. It is separated from BL by a distance β3. In the present embodiment, when the rotating body 200 rotates in the forward direction, the separation distance between the first magnetoresistive element 11 positioned at the most upstream and the fourth magnetoresistive element 22 positioned at the most downstream is adjacent in the rotation direction. It is equal to the total length α of the lateral widths of the pair of first magnetic pole part 210 and second magnetic pole part 220. Strictly speaking, each of the magnetoresistive effect elements 11, 12, 21, and 22 is arranged in the tangential direction of the midpoint between the first magnetoresistive effect element 11 and the fourth magnetoresistive effect element 22 in the rotation direction. The magnetoresistive elements 11 and 12 included in the first magnetoelectric converter 10 correspond to the first magnetoresistive elements described in the claims, and the magnetoresistive element included in the second magnetoelectric converter 20 is claimed. This corresponds to the second magnetoresistive elements 21 and 22 described in the range.

  Although not shown, each of the magnetoresistive effect elements 11, 12, 21, and 22 includes a free layer, a pinned layer, and an intermediate layer. The magnetization direction of the free layer changes according to the applied magnetic field, and the magnetization direction of the pinned layer is fixed. The intermediate layer is made of a nonmagnetic material and is provided between the pinned layer and the free layer. In the present embodiment, the intermediate layer has conductivity, and each of the magnetoresistive elements 11, 12, 21, and 22 is a giant magnetoresistive element. Each of the magnetoresistive elements 11, 12, 21, and 22 has a property that the resistance value fluctuates according to the magnetization directions of the pinned layer and the free layer. Therefore, when the magnetization direction of the free layer varies with the variation of the rotating magnetic field, the resistance values of the magnetoresistive effect elements 11, 12, 21, and 22 vary.

  When the magnetization directions of the free layer and the pinned layer are parallel, the resistance value fluctuates lowest, and when the magnetization direction is antiparallel, the resistance value fluctuates highest. The magnetization directions of the pin layers of the paired magnetoresistive elements 11 and 12 are generally along the radial direction, and the pinned layers of the paired magnetoresistive elements 21 and 22 are generally tangential to the rotational direction in which they are located. Along. Therefore, the magnetization directions of the pinned layers of the magnetoresistive effect elements 11 and 12 forming a pair and the magnetization directions of the pinned layers of the magnetoresistive effect elements 21 and 22 forming a pair are substantially orthogonal to each other. Further, the magnetization directions of the pin layers of the magnetoresistive effect elements 11 and 12 forming a pair are substantially antiparallel to each other, and the magnetization directions of the pin layers of the magnetoresistive effect elements 21 and 22 forming a pair are also approximately antiparallel to each other. Therefore, when the resistance values of the two magnetoresistive elements are opposite to each other, and the resistance value of one of the two magnetoresistive elements decreases, the resistance value of the other increases. As described above, the word “abbreviation” or “abbreviation” is used to describe the relationship between the magnetization directions of the pinned layer. However, as described later in the explanation of the feature points of the rotation angle sensor 100, This is because the magnetization direction is not along the radial direction or the tangential direction. In addition, the magnetization direction is not antiparallel and orthogonal. The above expression is only for the sake of simplicity.

  As shown in FIG. 3, a bridge circuit is formed by the magnetoresistive effect elements 11 and 12 forming a pair and the magnetoresistive effect elements 21 and 22 forming a pair, and the midpoint potential is changed to the rotating state of the rotating body 200. A signal based on the input is input to the calculation unit 50. The first half-bridge circuit is assembled by the magnetoresistive effect elements 11 and 12 that form a pair of the first magnetoelectric conversion unit 10, and the magnetoresistive effect element 21 that forms a pair of the second magnetoelectric conversion unit 20. , 22 form a second half bridge circuit. As described above, the magnetization directions of the pinned layers of the magnetoresistive effect elements 11 and 12 forming a pair and the magnetization directions of the pinned layers of the magnetoresistive effect elements 21 and 22 forming a pair are substantially orthogonal to each other. ing. Therefore, the phase difference between the midpoint potential of the first half bridge circuit (hereinafter referred to as the first midpoint potential) and the midpoint potential of the second half bridge circuit (hereinafter referred to as the second midpoint potential) is approximately 90. If the first midpoint potential is a sine wave, the second midpoint potential is a cosine wave.

  The calculation unit 50 calculates the rotation angle of the rotating body 200 based on the above-described midpoint potential. The calculation unit 50 has a first threshold value and a second threshold value. As shown in FIG. 4, the calculation unit 50 compares the midpoint potential of the first half bridge circuit with the first threshold value, converts the midpoint potential of the first bridge circuit into a first pulse signal, and outputs the second half bridge. The midpoint potential of the circuit is compared with the second threshold value to convert the midpoint potential of the second bridge circuit into a second pulse signal. The calculation unit 50 counts at least one rising edge or falling edge of the first pulse signal and the second pulse signal, and calculates the rotation angle of the rotating body 200 based on the count number.

  Next, characteristic points of the rotation angle sensor 100 will be described. As described above, each of the magnetoresistive effect elements 11, 12, 21, and 22 has a pinned layer, and the magnetization direction thereof is adjacent to the reference line BL in the rotation direction between the reference line BL and itself and in the rotation direction. It is determined by the combined length α of the lateral widths of the pair of first magnetic pole part 210 and second magnetic pole part 220. As shown in FIG. 5, each of the magnetoresistive effect elements 11 and 12 extends from the first virtual straight lines VL <b> 11 and VL <b> 12 along the radial direction connecting the rotation center RC of the rotating body 200 and its own center CP around the center CP thereof. The magnetization direction of the pinned layer is along the direction of (α / 360 °) × β rotation. Since the 1st magnetoresistive effect element 11 is located on the reference line BL, the separation distance with the reference line BL is zero. Therefore, the magnetization direction of the pinned layer of the first magnetoresistance effect element 11 is along the first virtual straight line VL11. On the other hand, the second magnetoresistive element 12 is separated from the reference line BL by β1. Therefore, the magnetization direction of the pinned layer of the second magnetoresistive effect element 12 is along the direction rotated by θ1 = (α / 360 °) × β1 around the center CP of itself from the second virtual straight line VL12. When the rotating body 200 rotates in the forward direction, the second magnetoresistive effect element 12 is positioned downstream of the reference line BL as shown in FIG. For this reason, the second magnetoresistive element 12 has a phase later than the reference line BL. In order to compensate for this phase lag, the magnetization direction of the pinned layer of the second magnetoresistive element 12 is rotated by θ1 counterclockwise around the center CP of the second magnetoresistive element 12 from the virtual straight line VL12. When the magnetization direction of the pinned layer of the first magnetoresistive effect element 11 is not rotated as described above, the magnetization directions of the pinned layers of the magnetoresistive effect elements 11 and 12 are along the radial direction and are antiparallel to each other. It has become a relationship. The magnetization directions of the pinned layers of the magnetoresistive elements 11 and 12 are different from each other by 180 ° −θ1.

  Each of the magnetoresistive elements 21 and 22 is rotated in the direction rotated by (α / 360 °) × β around the center CP from the second virtual straight lines VL21 and VL22 along the tangential direction of the rotation direction passing through the center CP. The magnetization direction of the pinned layer is along. The third magnetoresistance effect element 21 is separated from the reference line BL by β2. Therefore, the magnetization direction of the pinned layer of the third magnetoresistive effect element 21 is along the direction rotated by θ2 = (α / 360 °) × β2 around its own center CP from the virtual straight line VL21. The fourth magnetoresistive element 22 is separated from the reference line BL by β3. Therefore, the magnetization direction of the pinned layer of the fourth magnetoresistive effect element 22 is along the direction rotated by θ3 = (α / 360 °) × β3 around its center CP from the fourth virtual straight line VL22. When the rotating body 200 rotates forward, the magnetoresistive elements 21 and 22 are positioned on the downstream side of the reference line BL as shown in FIG. For this reason, the magnetoresistive effect elements 21 and 22 are in a relationship of phases later than the reference line BL. In order to compensate for this phase lag, the magnetization direction of the pinned layer of the third magnetoresistive element 21 rotates θ2 counterclockwise around the center CP of the third magnetoresistive element 21 from the virtual straight line VL21. The magnetization direction of the pinned layer rotates θ3 counterclockwise around the center CP of itself from the virtual straight line VL22. When the magnetization directions of the pin layers of the magnetoresistive elements 21 and 22 are not rotated as described above, the magnetization directions of the pin layers of the magnetoresistive elements 21 and 22 are in an antiparallel relationship. . The magnetization directions of the pinned layers of the magnetoresistive elements 11 and 12 are different from each other by 180 ° − (α / 360 °) × (β3−β2).

  Next, functions and effects of the rotation angle sensor 100 according to the present embodiment will be described. As described above, the magnetoresistive effect elements 11, 12, 21, and 22 are arranged side by side along the rotation direction. According to this, unlike the configuration in which a plurality of magnetoresistive elements are arranged in the radial direction rather than in the rotational direction, the strength of the magnetic flux transmitted through each magnetoresistive element is the same. However, in the case of the arrangement described above, the phases of the magnetic fluxes transmitted through the magnetoresistive elements 11, 21, 21, 22 are different. In other words, the magnetic flux (hereinafter referred to as the reference magnetic flux BM) that passes through the intersection of the reference line BL and the rotational direction in which the magnetoresistive elements 11, 12, 21, and 22 are arranged is separated from the reference line BL in the rotational direction. The phase is different from the magnetic flux passing through the position. As shown in FIG. 6, since the first magnetoresistance effect element 11 is located on the reference line BL, the magnetization direction of the free layer of the first magnetoresistance effect element 11 faces the same direction as the reference magnetic flux BM. However, since each of the other magnetoresistive elements 12, 21, 22 is away from the reference line BL, the magnetization direction of each free layer faces a direction different from the reference magnetic flux BM.

  However, the phase deviation from the reference magnetic flux BM described above is the sum of the width α of the first magnetic pole part 210 and the second magnetic pole part 220, and the reference line BL and the magnetoresistive effect element along the rotation direction. 11, 12, 21, 22 and the separation distance β. More specifically, since the second magnetoresistive element 12 is separated by β1 downstream from the reference line BL, the magnetization direction of the free layer of the second magnetoresistive element 12 makes the reference magnetic flux BM counterclockwise. It is along the direction rotated by θ1. Similarly, since the third magnetoresistive effect element 21 is separated by β2 downstream from the reference line BL, the magnetization direction of the free layer of the third magnetoresistive effect element 21 rotates the reference magnetic flux BM counterclockwise by θ2. Along the direction. Further, since the fourth magnetoresistance effect element 22 is separated by β3 downstream from the reference line BL, the magnetization direction of the free layer of the fourth magnetoresistance effect element 22 rotates the reference magnetic flux BM counterclockwise by θ3. Along the direction. Thus, although the magnetization direction of the free layer of each magnetoresistive effect element 11, 12, 21, 22 is different from the case where it is located on the reference line BL, the phase shift is represented by α and β. The

  On the other hand, in this embodiment, the magnetization directions of the pinned layers of the plurality of magnetoresistive elements 11, 12, 21, 22 are determined by the separation distance β and the length α, and the magnetoresistive elements 11, 21, respectively. The phase shift of 21 and 22 is suppressed. Specifically, since the first magnetoresistive element 11 is located on the reference line BL, the magnetization direction of the pinned layer is not rotated. However, the magnetization direction of the pinned layer of the second magnetoresistive element 12 is the virtual straight line VL12. Is rotating around the center CP of its own counterclockwise by θ1. Similarly, the magnetization direction of the pinned layer of the third magnetoresistive effect element 21 rotates θ2 counterclockwise around its center CP from the virtual straight line VL21, and the magnetization direction of the pinned layer of the fourth magnetoresistive effect element 22 becomes In addition, it rotates θ3 counterclockwise around its center CP from the virtual straight line VL22.

  Thereby, as shown in FIG. 7, the magnetization directions of the pinned layer and the free layer of the magnetoresistive effect elements 12, 21, and 22 rotate by θ1, θ2, and θ3 counterclockwise. Therefore, unlike the configuration in which the magnetization direction of the pinned layer is not rotated according to the separation distance β from the reference line BL (comparative configuration shown in FIGS. 8 and 9), the magnetoresistive effect elements 11, 12, 21, and 22 are used. The angle formed by the magnetization directions of the pinned layer and the free layer of each is the same as when the angle is located on the reference line BL. As described above, the strength of the magnetic flux transmitted through the magnetoresistive effect elements 11, 12, 21, and 22 becomes the same, and the phase shift is eliminated. Based on the electrical signal (midpoint potential of the bridge circuit) that depends on the resistance values of these magnetoresistive elements 11, 12, 21, and 22, the detection accuracy of the rotating state of the rotating body 200 is improved.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  In the present embodiment, an example in which the first magnetoresistance effect element 11 is located on the reference line BL is shown. However, the reference line BL and the positions of the magnetoresistive elements 11, 12, 21, 22 can be arbitrarily set. For example, as shown in FIG. 10, the reference line BL may be determined so as to pass through the middle of the magnetoresistive effect elements 11, 12, 21, and 22. In this case, the first magnetoresistance effect element 11 is separated by β4 from the reference line BL, and the second magnetoresistance effect element 12 is separated by β5 from the reference line BL. The third magnetoresistive element 21 is separated by β6 from the reference line BL, and the fourth magnetoresistive element 22 is separated by β7 from the reference line BL. As a result, as shown in FIG. 11, the magnetization direction of the pinned layer of the first magnetoresistive effect element 11 is rotated by θ4 = (α / 360 °) × β4 around its center CP from the virtual straight line VL11, 2 The magnetization direction of the pinned layer of the magnetoresistive effect element 12 is rotated by θ5 = (α / 360 °) × β5 around its center CP from the virtual straight line VL12. Further, the magnetization direction of the pinned layer of the third magnetoresistive effect element 21 rotates by θ6 = (α / 360 °) × β6 around its own center CP from the virtual straight line VL21, and the pin of the fourth magnetoresistive effect element 22 The magnetization direction of the layer is rotated by θ7 = (α / 360 °) × β7 around its own center CP from the virtual straight line VL22. When the rotating body 200 rotates forward, each of the magnetoresistive effect elements 11 and 12 is positioned upstream of the reference line BL. Therefore, the magnetoresistive effect elements 11 and 12 are in a phase relationship that is faster than the reference line BL. In order to compensate for this, the magnetization direction of the pinned layer of the first magnetoresistive effect element 11 is rotated by θ4 clockwise around its center CP from the virtual straight line VL11. Similarly, the magnetization direction of the pinned layer of the second magnetoresistive effect element 12 is rotated by θ5 clockwise around its center CP from the virtual straight line VL12. Unlike this, each of the magnetoresistive effect elements 21 and 22 is located downstream of the reference line BL. For this reason, the magnetoresistive effect elements 21 and 22 have a phase later than that of the reference line BL. In order to compensate for this, the magnetization direction of the pinned layer of the third magnetoresistive effect element 21 is rotated by θ6 clockwise around its center CP from the virtual straight line VL21. Similarly, the magnetization direction of the pinned layer of the fourth magnetoresistive effect element 22 is rotated by θ7 clockwise around its center CP from the virtual straight line VL22.

  In the present embodiment, as shown in FIGS. 1 and 2, the first magnetoresistance effect element 11, the second magnetoresistance effect element 12, the third magnetoresistance effect element 21, and the fourth magnetoresistance effect are arranged along the rotation direction. An example in which the elements 22 are arranged in order is shown. However, the arrangement order of these magnetoresistive effect elements 11, 12, 21, 22 is not limited to the above example. For example, as shown in FIG. 12, the first magnetoresistive effect element 11, the third magnetoresistive effect element 21, the fourth magnetoresistive effect element 22, and the second magnetoresistive effect element 12 are arranged in order along the rotation direction. It can also be adopted.

  In the present embodiment, the first magnetoelectric conversion unit 10 includes a pair of magnetoresistive effect elements 11 and 12, and the second magnetoelectric conversion unit 20 includes a pair of magnetoresistive effect elements 21 and 22. An example is shown. However, the number of pairs of magnetoresistive effect elements forming a pair included in each of the magnetoelectric conversion units 10 and 20 is not limited to the above example, and a plurality may be used. For example, as shown in FIG. 13, the first magnetoelectric conversion unit 10 has two pairs of magnetoresistive effect elements 11 to 14, and the second magnetoelectric conversion unit 20 forms two pairs of magnetoresistive effect elements 21. A configuration having ˜24 can also be adopted. In this case, as shown in FIGS. 14 and 15, two first half-bridge circuits are formed by the magnetoresistive effect elements 11 to 14 forming two pairs, and the first full-bridge circuit is formed by these. In addition, two second half-bridge circuits are formed by the magnetoresistive effect elements 21 to 24 forming two pairs, and the second full-bridge circuit is formed by these. The calculation unit 50 calculates the rotation angle of the rotator 200 based on the midpoint potential of these two full bridge circuits.

  In the present embodiment, as shown in FIGS. 1 and 2, the separation distance between the first magnetoresistive effect element 11 and the fourth magnetoresistive effect element 22 in the rotation direction is a pair of first magnetic poles adjacent in the rotation direction. An example is shown in which the lateral lengths of the portion 210 and the second magnetic pole portion 220 are equal to the combined length α. However, as shown in FIGS. 16 and 17, the distance between the first magnetoresistive element 11 and the fourth magnetoresistive element 22 is not limited to the above example. The separation distance of the magnetoresistive effect elements 11, 12, 21, and 22 in the rotation direction is not limited.

  In the present embodiment, an example is shown in which the magnetoresistive elements 11, 12, 21, and 22 are arranged in the tangential direction of the midpoint of the magnetoresistive elements 11, 12, 21, and 22 in the rotational direction. However, as shown in FIGS. 16 and 17, the magnetoresistive elements 11, 12, 21, and 22 may be arranged in the rotation direction.

  In the present embodiment, the overall shape of the rotating body 200 is not particularly limited. However, as the overall shape of the rotating body 200, an annular shape or a disk shape can be adopted.

  In the present embodiment, an example is shown in which the intermediate layer has conductivity, and each of the magnetoresistive effect elements 11, 12, 21, and 22 is a giant magnetoresistive effect element. However, it is also possible to adopt a configuration in which the intermediate layer has insulating properties and each of the magnetoresistive effect elements 11, 12, 21, and 22 is a tunnel magnetoresistive effect element.

11-14, 21-24 ... magnetoresistive effect element 100 ... rotation angle sensor 200 ... rotating body 210 ... first magnetic pole part 220 ... second magnetic pole part RC ... rotation center BL ... Reference line

Claims (8)

The first magnetic pole portion (210) and the second magnetic pole portion (220) having the same lateral width in the rotation direction are alternately connected along the rotation direction, and the rotation of the rotating body (200) whose outer surface is circular. A rotation angle sensor for detecting an angle,
A free layer whose magnetization direction changes according to a rotating magnetic field generated from the rotating body, a pinned layer whose magnetization direction is fixed, and a nonmagnetic intermediate layer provided between the pinned layer and the free layer And a plurality of magnetoresistive elements (11-14, 21-24) whose resistance values vary according to the magnetization directions of the pinned layer and the free layer,
Each of the plurality of magnetoresistive elements is arranged side by side along the rotation direction so that the distance from the outer surface of the rotating body is constant.
The magnetization direction of the pinned layer of each of the plurality of magnetoresistive elements is aligned with one reference line (BL) extending perpendicularly to the rotation direction from the rotation center (RC) of the rotating body and the rotation direction. It is determined by a separation distance β from the magnetoresistive effect element and a total length α of a lateral width of each of the pair of the first magnetic pole part and the second magnetic pole part adjacent in the rotation direction. A rotation angle sensor. As the plurality of magnetoresistance effect elements,
Magnetization direction of the pinned layer in a direction rotated by (α / 360 °) × β around the center from the first virtual line (VL11, VL12) connecting the rotation center of the rotating body and the center (CP) of the rotating body. A plurality of first magnetoresistive elements (11-14) along which
The magnetization direction of the pinned layer extends along a direction rotated by (α / 360 °) × β around the center of the second virtual straight line (VL21, VL22) along the tangential direction of the rotational direction passing through the center of the self. The rotation angle sensor according to claim 1, comprising a plurality of second magnetoresistive elements (21 to 24). At least one of the plurality of first magnetoresistive elements has a magnetization direction of the pinned layer that differs by 180 ° − (α / 360 °) × β, thereby forming a first bridge circuit,
At least one set of the plurality of second magnetoresistive elements has a magnetization direction of the pinned layer different by 180 ° − (α / 360 °) × β, and the second bridge circuit is formed by these. The rotation angle sensor according to claim 2, wherein:   The calculation unit (50) for calculating a rotation angle of the rotating body based on a midpoint potential of the first bridge circuit and a midpoint potential of the second bridge circuit. Rotation angle sensor. The calculation unit includes:
Having a first threshold and a second threshold;
Comparing the midpoint potential of the first bridge circuit with the first threshold to convert the midpoint potential of the first bridge circuit into a first pulse signal;
The rotation angle sensor according to claim 4, wherein the midpoint potential of the second bridge circuit is compared with the second threshold value to convert the midpoint potential of the second bridge circuit into a second pulse signal. .   The calculation unit counts at least one rising edge or falling edge of the first pulse signal and the second pulse signal, and calculates a rotation angle of the rotating body based on the count number. The rotation angle sensor according to claim 5. The first bridge circuit has at least one first half bridge circuit assembled by the first magnetoresistive effect element forming a pair.
The said 2nd bridge circuit has at least 1 2nd half bridge circuit assembled | attached by the said 2nd magnetoresistive effect element which makes a set of pairs, The any one of Claims 3-6 characterized by the above-mentioned. Rotation angle sensor. The first bridge circuit includes two first half-bridge circuits, and includes a first full-bridge circuit formed by these two circuits.
The rotation angle sensor according to claim 7, wherein the second bridge circuit includes two second half-bridge circuits and includes a second full-bridge circuit formed by these two.

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