JP2019090789A - Rotation detector - Google Patents

Abstract

To provide a rotation detector with which it is possible to increase the magnitude of a differential signal.SOLUTION: The rotation detector comprises: a sensor chip 21 including a first element 211 and a second element 212 formed, with a center-to-center distance β less than a magnetization pitch λ, on a detection surface 21d orthogonal to a magnetization surface 10m of a magnetization rotor 10; a bias magnet 22; and a circuit chip 23 for generating a differential signal. The first element and the second element are arranged on the bias magnet so as to satisfy 2×{180°-(β/α)×360°}>(θ1-θ2)>0, where θ1 represents an angle formed by a reference line parallel to the opposing direction of the sensor chip and the magnetization surface and running along the detection surface and the magnetic vector of a bias magnetic field acting on the first element, and θ2 represents an angle formed by the reference line and the magnetic vector of a bias magnetic field acting on the second element, with the magnetic vector acting on the first element inclined to the second element side relative to the reference line, so that θ1>0 holds, the magnetic vector acting on the second element inclined to the first element side relative to the reference line, so that θ2<0 holds.SELECTED DRAWING: Figure 3

Description

  The disclosure in this specification relates to a rotation detection device.

  DESCRIPTION OF RELATED ART As described in patent document 1, the rotation detection apparatus which detects the rotation state of a magnetizing rotor is known. The magnetizing rotor has a magnetizing surface in which N poles and S poles are alternately magnetized in the rotational direction at a magnetization pitch λ. The rotation detection device includes a sensor chip (substrate) having a detection surface orthogonal to the magnetization surface and a plurality of magnetoresistance effect elements formed on the detection surface and whose resistance value changes as the magnetization rotor rotates. Have.

JP, 2010-145166, A

  In the rotation detection device, the amplitude of the obtained signal is increased by generating a differential signal from the outputs of the plurality of elements. For example, in the case of two elements, when the center-to-center distance of the elements is equal to the magnetization pitch λ, the phase difference of the output is 180 °, and the differential signal can be increased.

  However, if the center-to-center distance can not be made equal to the magnetization pitch λ due to miniaturization of the rotation detection device, the differential signal becomes small.

  This indication is made in view of such a subject, and it aims at providing a rotation detecting device which can enlarge a differential signal.

  The present disclosure employs the following technical means to achieve the above object. In addition, the code | symbol in a parenthesis shows correspondence with the specific means as described in embodiment mentioned later as one aspect, and does not limit a technical scope.

The rotation detection device which is one of the present disclosure is
A rotation detection device for detecting the rotational state of a magnetized rotor (10) having a magnetized surface (10 m) in which magnetization poles λ and magnetization cycles α and N and S poles are alternately magnetized in the rotational direction There,
It has a detection surface (21d) orthogonal to the magnetization surface and a plurality of magnetoresistance effect elements (210) formed on the detection surface and whose resistance value changes as the magnetization rotor rotates. A sensor chip (21) including, as elements, a first element (211) and a second element (212) arranged such that a center distance β to the first element is less than a magnetization pitch λ;
At least one bias magnet (22) for applying a bias magnetic field to the plurality of magnetoresistive elements;
A differential unit (230) that generates a differential signal from the outputs of the first element and the second element;
Equipped with
The angle between the reference line (L1) parallel to the facing direction of the sensor chip and the magnetized surface and along the detection surface and the magnetic vector of the bias magnetic field acting on the first element is θ1, Assuming that the angle between the bias magnetic field acting on the two elements and the magnetic vector is θ2,
In an environment where a magnetic field different from the bias magnetic field is not applied,
The magnetic vector acting on the first element is inclined to the second element side with respect to the reference line to be θ1> 0, and the magnetic vector acting on the second element is inclined to the first element side to the reference line to θ2 < While being 0,
2 × {180 ° − (β / α) × 360 °}>(θ1−θ2)> 0
The first element and the second element are disposed with respect to the bias magnet so as to satisfy

  According to this rotation detection device, the first element and the second element are arranged at positions where the magnetic vector of the bias magnetic field parallel to the reference line acts under an environment where a magnetic field different from the bias magnetic field is not applied. In comparison, the differential signal can be made larger.

Another rotation detection device according to the present disclosure is
A rotation detection device for detecting the rotational state of a magnetized rotor (10) having a magnetized surface (10 m) in which magnetization poles λ and magnetization cycles α and N and S poles are alternately magnetized in the rotational direction There,
It has a detection surface (21d) orthogonal to the magnetization surface and a plurality of magnetoresistance effect elements (210) formed on the detection surface and whose resistance value changes as the magnetization rotor rotates. As the element, the third element (213), the fourth element (214) arranged so that the center distance γ to the third element is less than the magnetization pitch λ, and the distance between the third element and the fourth element A sensor chip (21) comprising a fifth element (215) arranged;
At least one bias magnet (22) for applying a bias magnetic field to the plurality of magnetoresistive elements;
A differential unit (231, 232, 233) that generates a differential signal from the outputs of the third element, the fourth element, and the fifth element;
Equipped with
The angle between the reference line (L1) parallel to the opposing direction of the sensor chip and the magnetization surface and along the detection surface and the magnetic vector of the bias magnetic field acting on the third element is θ3, Assuming that the angle between the bias magnetic field acting on the four elements and the magnetic vector is θ4
In an environment where a magnetic field different from the bias magnetic field is not applied,
The magnetic vector acting on the third element is inclined to the fourth element side with respect to the reference line to be θ3> 0, and the magnetic vector acting on the fourth element is inclined to the third element side to the reference line to θ4 < While being 0,
2 × {360 ° − (γ / α) × 360 °}>(θ3−θ4)> 0
The third element and the fourth element are disposed with respect to the bias magnet so as to satisfy the following.

  According to this rotation detection device, the third element and the fourth element are disposed at positions where the magnetic vector of the bias magnetic field parallel to the reference line acts under an environment where a magnetic field different from the bias magnetic field is not applied. In comparison, the differential signal can be made larger.

It is a top view which shows the positional relationship of the rotation detection apparatus of 1st Embodiment, and a magnetizing rotor. FIG. 2 is a cross-sectional view taken along the line II-II in FIG. It is the figure which expanded the rotation detection apparatus periphery of FIG. It is a circuit diagram showing a rotation detecting device. It is a figure for demonstrating rotation direction discrimination. It is a figure which shows the relationship between a rotation position and direction of the magnetic vector of a rotor magnetic field. It is a figure which shows the change of direction of the magnetic vector of a rotor magnetic field in 1 period of magnetization. It is a figure which shows an example of arrangement | positioning of a bias magnet and an element. FIG. 9 shows magnetic vectors acting on the element in the arrangement shown in FIG. 8; FIG. 9 is a diagram showing an output waveform of the element in the arrangement shown in FIG. 8; It is a figure which shows the other example of arrangement | positioning of a bias magnet and an element. FIG. 12 is a diagram showing magnetic vectors acting on elements in the arrangement shown in FIG. FIG. 12 is a diagram showing output waveforms of elements in the arrangement shown in FIG. It is a figure which shows the phase of a signal. It is a figure which shows the relationship between the angle of the magnetic vector of a bias magnetic field, and the phase of the signal in rotation position P1. It is a figure which shows the positional relationship of a magnetization rotor, a 1st element, and a 2nd element. It is a figure which shows the relationship between the phase difference ((theta) 1- (theta) 2) resulting from the magnetic vector of a bias magnetic field, and the amplitude of differential signal S1. It is a figure which shows the concrete signal waveform which shows the effect of the magnetic vector of a bias magnetic field. It is a figure which shows the specific example of the element arrangement | positioning with respect to a bias magnet. It is a figure which shows the positional relationship of a magnetization rotor, a 3rd element, a 4th element, and a 5th element. It is a figure which shows the waveform of the signals C, D, and E. FIG. It is a figure which shows the waveform of various signals in case the phase difference of the signals C and D is 0 degree-180 degrees. It is a figure which shows the waveform of various signals in case the phase difference of the signals C and D is 180 degrees. It is a figure which shows the waveform of various signals in case the phase difference of the signals C and D is 180 degrees-360 degrees. It is a figure which shows the waveform of various signals in case the phase difference of the signals C and D is 360 degrees. It is a figure which shows the relationship between the phase difference ((theta) 3- (theta) 4) resulting from the magnetic vector of a bias magnetic field, and the amplitude of differential signal S2. It is a figure which shows the concrete signal waveform which shows the effect of the magnetic vector of a bias magnetic field. It is a figure which shows the influence of an external magnetic field. It is a figure which shows the high sensitivity element used for the rotation detection apparatus of 2nd Embodiment, and a low sensitivity element. It is a figure which shows the specific example of the element arrangement | positioning with respect to a bias magnet. It is a figure which shows the modification of arrangement | positioning of the element with respect to a bias magnet. It is a figure which shows the modification of arrangement | positioning of the rotation detection apparatus with respect to a magnetizing rotor.

  Several embodiments will be described with reference to the drawings. In embodiments, functionally and / or structurally corresponding parts are provided with the same reference signs. Hereinafter, the direction along the rotation axis of the magnetizing rotor is referred to as Z1-Z2 direction, and one direction orthogonal to the Z1-Z2 direction is referred to as Y1-Y2 direction. A direction orthogonal to both the Z1-Z2 direction and the Y1-Y2 direction is referred to as an X1-X2 direction. Unless otherwise specified, the shape of the surface defined by the X1-X2 direction and the Y1-Y2 direction is a planar shape.

First Embodiment
First, based on FIGS. 1-5, schematic structure of a magnetizing rotor and a rotation detection apparatus is demonstrated. FIG. 3 is an enlarged view of a part of FIG. 1, specifically, the periphery of the rotation detection device. In FIG. 3 which is an enlarged view, the magnetizing rotor is shown linearly for convenience. In FIG. 3, the sealing resin body is omitted for convenience. About the circuit structure shown in FIG. 4, the description of Unexamined-Japanese-Patent No. 2017-9411 can be used.

  As shown in FIGS. 1 to 3, the magnetizing rotor 10 rotates with the rotating body to be fixed. The magnetized rotor 10 is fixed to a rotating body such as a crankshaft or an axle of an engine in a vehicle, for example. The magnetized rotor 10 has a magnetized surface 10 m. In the present embodiment, the magnetizing rotor 10 has a planar substantially annular plate shape, and as shown in FIG. 2, in the magnetizing rotor 10, the outer peripheral end face (side surface) orthogonal to the rotation axis is the magnetizing surface 10m. It is done. As shown in FIG. 3, in the magnetized surface 10m, the N pole 10n and the S pole 10s are alternately magnetized in the rotational direction at a magnetization pitch λ and a magnetization period α. The magnetization period α is 2 × λ.

  The rotation detection device 20 detects the rotation state of the magnetizing rotor 10. The rotation detection device 20 constitutes a rotation detection system together with the magnetizing rotor 10. The rotation detection device 20 is disposed to face the magnetizing surface 10 m with a predetermined gap. The rotation detection device 20 includes a sensor chip 21, a bias magnet 22, a circuit chip 23, a lead frame 24, and a sealing resin body 25.

  The lead frame 24 is disposed such that the thickness direction is substantially parallel to the Z1-Z2 direction. The sensor chip 21 and the circuit chip 23 are fixed to the same surface of the island 24 a of the lead frame 24. The bias magnet 22 is fixed to the surface opposite to the one surface of the island 24a. The sensor chip 21 is electrically connected to the circuit chip 23 through the bonding wire 26. The circuit chip 23 is electrically connected to the terminals 24 b to 24 d of the lead frame 24 through the bonding wires 26. The terminal 24 b is a terminal for ground (GND) and is connected to the island 24 a. The terminal 24c is a terminal for the power supply (Vcc), and the terminal 24d is a terminal for the output (Vout).

  The sealing resin body 25 integrally seals a part of the lead frame 24 including the sensor chip 21, the bias magnet 22, the circuit chip 23, and the island 24 a. Sealing resin body 25 is formed using, for example, an epoxy resin. Sealing resin body 25 is formed, for example, by a transfer molding method. The terminals 24 b to 24 d are extended in the Y 2 direction and protrude from the sealing resin body 25 to the outside.

  The sensor chip 21 is a semiconductor chip on which the magnetoresistive effect element 210 whose resistance value changes with the rotation of the magnetized rotor 10 is formed. As shown in FIG. 3, the sensor chip 21 has a detection surface 21 d orthogonal to the magnetized surface 10 m. A plurality of magnetoresistance effect elements 210 are formed on the detection surface 21d. As the magnetoresistive effect element 210, an anisotropic magnetoresistive effect element (AMR element), a tunnel type magnetoresistive effect element (TMR element), a giant magnetoresistive effect element (GMR element) or the like can be employed. The sensor chip 21 has a flat, substantially rectangular plate shape, and the upper surface opposite to the lower surface facing the lead frame 24 is a detection surface 21 d.

  The sensor chip 21 includes a first element 211, a second element 212, a third element 213, a fourth element 214, and a fifth element 215 as the magnetoresistance effect element 210. The first element 211, the second element 212, the third element 213, the fourth element 214, and the fifth element 215 are configured as a half bridge circuit in which the magnetoresistive elements 210 are connected in series. In each of the first element 211, the second element 212, the third element 213, the fourth element 214, and the fifth element 215, a pair of magnetoresistance effect elements 210 are arranged in a V shape.

  As shown in FIG. 4, the first element 211 is composed of two magnetoresistive elements 210 connected in series between the power supply (Vcc) and the ground (GND). The first element 211 detects a change in resistance when the two magnetoresistance effect elements 210 are affected by the magnetic field as the magnetized rotor 10 rotates. The first element 211 outputs the midpoint voltage A of the two magnetoresistive elements 210 as a signal. The second element 212 to the fifth element 215 also have the same configuration as the first element 211. The second element 212 is composed of two magnetoresistive elements 210 and outputs a midpoint voltage B.

  The third element 213 is composed of two magnetoresistive elements 210 and outputs a midpoint voltage C. The fourth element 214 is composed of two magnetoresistive elements 210 and outputs a midpoint voltage D. The fifth element 215 is composed of two magnetoresistive elements 210 and outputs a midpoint voltage E.

  As shown in FIG. 3, the first element 211 and the second element 212 are arranged such that the center distance β of the elements is less than the magnetization pitch λ. The third element 213 and the fourth element 214 are arranged such that the center distance γ of the elements is less than the magnetization pitch λ. The fifth element 215 is disposed between the third element 213 and the fourth element 214 in the arrangement direction of the third element 213 and the fourth element 214.

  The bias magnet 22 increases the detection sensitivity of the magnetic field of the sensor chip 21 by a fixed amount by applying a bias magnetic field to the sensor chip 21, that is, the plurality of magnetoresistance effect elements 210. In the present embodiment, the bias magnet 22 is in the form of a substantially rectangular flat plate. The N pole 22 n and the S pole 22 s of the bias magnet 22 are arranged side by side in the plane defined by the X1-X2 direction and the Y1-Y2 direction. In the present embodiment, the N pole 22n and the S pole 22s are arranged side by side in the Y1-Y2 direction, and the boundary 22b between the N pole 22n and the S pole 22s is substantially orthogonal to the Y1-Y2 direction. A magnetic pole center line 22c passing through the magnetic pole centers of the N pole 22n and the S pole 22s is substantially parallel to the Y1-Y2 direction. The bias magnet 22 is disposed so as to overlap the sensor chip 21 in the projection view in the Z1-Z2 direction. The details of the arrangement of the first element 211, the second element 212, the third element 213, the fourth element 214, the fifth element 215, and the bias magnet 22 will be described later.

  The circuit chip 23 is a semiconductor chip in which the processing circuit of the sensor chip 21 is formed. The circuit chip 23 includes differential amplifiers 230 to 233, a threshold generation unit 234, comparators 235 and 236, and a determination unit 237. In the present embodiment, the sensor chip 21 and the circuit chip 23 are disposed side by side in the Y1-Y2 direction with the circuit chip 23 on the Y2 side.

  The differential amplifier 230 calculates (A−B) which is the difference between the signals A and B, and outputs it as a differential signal S1. The differential amplifier 230 corresponds to a differential unit that generates an operation signal from the outputs of the first element 211 and the second element 212. Differential signal S1 is a node at the boundary between N pole 10n and S pole 10s, as shown in FIG. 5, for example, and the amplitude is maximum or minimum (ie peak) at the pole center.

  The differential amplifier 231 calculates (E−C) which is the difference between the signals E and C, and outputs the result. The differential amplifier 232 calculates (D−E) which is the difference between the signals D and E, and outputs the result. The differential amplifier 233 receives (E-C) from the differential amplifier 231 and receives (D-E) from the differential amplifier 232. The differential amplifier 233 calculates (E−C) − (D−E) and outputs the result as a differential signal S2. That is, differential signal S2 = 2E- (C + D). The differential amplifiers 231 to 233 correspond to a differential unit that generates an operation signal from the outputs of the third element 213, the fourth element 214, and the fifth element 215.

  The differential signal S2 is a signal having a phase difference with respect to the differential signal S1. For example, as shown in FIG. 5, the differential signal S2 peaks at the boundary between the N pole 10n and the S pole 10s, and becomes a node at the pole center.

  The threshold generation unit 234 generates a threshold Vth for binarizing the differential signals S1 and S2. The threshold generation unit 234 is formed of, for example, two resistors (not shown) connected in series between the power supply and the ground, and a midpoint voltage is used as the threshold Vth.

  The comparator 235 compares the differential signal S1 with the threshold value Vth to generate a signal S3 obtained by binarizing the differential signal S1. The comparator 236 compares the differential signal S2 with the threshold value Vth to generate a signal S4 obtained by binarizing the differential signal S2.

  The determination unit 237 determines, based on the signals S3 and S4 output from the comparators 235 and 236, whether the rotation direction of the magnetizing rotor 10 is forward rotation or reverse rotation. The determination unit 237 outputs the information indicating the rotational position of the magnetizing rotor 10 and the information indicating the rotation direction of the magnetizing rotor 10 to an external device (not shown) via the output terminal 27 (Vout). The information indicating the rotational position is based on either of the above-described signals S3 and S4.

  In the case of normal rotation, for example, as shown in FIG. 5, the amplitude of differential signal S2 is smaller than threshold Vth before time T1 and larger than threshold Vth after time T1. Therefore, the signal S4 switches from Lo to Hi at time T1. Further, since the amplitude of the differential signal S1 is larger than the threshold value Vth before and after time T1, the signal S3 becomes Hi at time T1. When the signal S4 rises from Lo to Hi and the signal S3 is Hi, the determination unit 237 determines that the magnetized rotor 10 is normally rotating.

  In the reverse case, the amplitude of the differential signal S2 is larger than the threshold Vth before time T1 and smaller than the threshold Vth after time T1. Therefore, the signal S4 switches from Hi to Lo at time T1. Since the amplitude of the differential signal S1 is larger than the threshold Vth before and after time T1, the signal S3 becomes Hi at time T1. If the signal S4 falls from Hi to Lo and the signal S3 is Hi, the determination unit 237 determines that the magnetized rotor 10 is reversely rotated.

  The rotation detection device 20 includes a power supply terminal 28 (Vcc) and a ground terminal 29 (GND) connected to an external device. The rotation detection device 20 is supplied with power from an external device through the power supply terminal 28 and the ground terminal 29.

  Next, the details of the arrangement of the magnetoresistive effect element 210 and the bias magnet 22 will be described based on FIG. 3 and FIGS. The magnetized rotor 10 shown in FIG. 6, FIG. 8, FIG. 11, FIG. 16, and FIG. 20 corresponds to FIG. For example, in FIG. 6, rotation in the X2 direction indicates normal rotation, and rotation in the X1 direction indicates reverse rotation. In the present embodiment, the angle of the magnetic vector is indicated with the counterclockwise direction as the positive direction. Further, the magnetic vector acting on the element is such that the bias magnetic field is larger than the rotor magnetic field. The magnetic vector of the bias magnetic field indicates a state not affected by another magnetic field including the rotor magnetic field, and the magnetic vector of the combined magnetic field indicates a state affected by the rotor magnetic field.

(Relationship between the angle of the magnetic vector of the bias magnetic field and the phase of the signal)
First, the relationship between the angle of the magnetic vector of the bias magnetic field acting on the element and the phase of the signal will be described with reference to FIGS. In the following, for example, as shown in FIG. 6, the magnetic pole center of N pole 10n is set as rotational position P1 and the boundary between N pole 10n and S pole 10s is set as rotational position P2 in one period of magnetization. Further, the center of the magnetic pole of the south pole 10s is taken as a rotational position P3, and the boundary between the south pole 10s and the north pole 10n is taken as a rotational position P4. In the case of normal rotation, the facing position of the magnetizing rotor 10 with the element changes in the order of P 1 → P 2 → P 3 → P 4. In FIGS. 8 to 15, the first element 211 will be described as an example of the element. Also, the reference position of the angle of the magnetic vector is taken as the X1 axis.

  The direction of the magnetic vector of the magnetizing rotor 10 acting on an element not shown is, as shown in FIG. 6, a direction substantially parallel to the Y1-Y2 direction at the rotational position P1 and away from the magnetizing surface 10m, ie It becomes Y2 direction. At the rotational position P3, the opposite direction to the rotational position P1, that is, the Y1 direction. The rotational positions P2 and P4 are substantially parallel to the X direction, and are opposite to each other. Specifically, in the rotational position P2, it is in the X1 direction, and in the rotational position P4, it is in the X2 direction. Therefore, as shown in FIG. 7, the magnetic vector of the rotor magnetic field rotates 360 ° during one magnetization period.

  As shown in FIG. 8, when the bias magnet 22 is disposed, the magnetic vector of the bias magnetic field acts on the first element 211 as an element. In FIG. 8, the bias magnet is so arranged that the N pole 22 n and the S pole 22 s align in the Y1-Y2 direction with the N pole 22 n on the Y1 side (magnetization rotor 10 side) and the boundary 22 b is substantially orthogonal to the Y1-Y2 direction 22 are arranged. Further, the first element 211 is disposed on the boundary 22 b, and the direction of the magnetic vector of the bias magnetic field acting on the first element 211 is the Y2 direction.

  A magnetic vector of a combined magnetic field of the bias magnetic field and the rotor magnetic field acts on the first element 211. The direction of the magnetic vector of the rotor magnetic field acting on the first element 211 rotates 360 ° during one magnetization cycle as described above. Therefore, the magnetic vector of the combined magnetic field changes in accordance with the rotational positions P1 to P4 of the magnetizing rotor 10, as shown in FIG.

  In the case of the rotational position P1, the direction of the magnetic vector of the rotor magnetic field is the same as the magnetic vector of the bias magnetic field, that is, the Y2 direction. Therefore, the magnetic vector of the combined magnetic field is obtained by adding the magnetic vector of the rotor magnetic field to the magnetic vector of the bias magnetic field, and the angle θxy of the magnetic vector of the combined magnetic field is 270 °. In the case of the rotational position P2, the direction of the magnetic vector of the rotor magnetic field is the X1 direction. Therefore, the angle θxy of the magnetic vector of the combined magnetic field is larger than 270 ° and smaller than 360 °.

  In the case of the rotational position P3, the direction of the magnetic vector of the rotor magnetic field is opposite to the magnetic vector of the bias magnetic field, that is, the Y1 direction. Accordingly, the magnetic vector of the combined magnetic field is obtained by subtracting the magnetic vector of the rotor magnetic field from the magnetic vector of the bias magnetic field, and the angle θ xy is 270 °. In the case of the rotational position P4, the direction of the magnetic vector of the rotor magnetic field is the X2 direction. Therefore, the angle θxy of the magnetic vector of the combined magnetic field is larger than 180 ° and smaller than 270 °.

  The output (signal A) of the first element 211 changes in accordance with the rotational positions P1 to P4 as shown in FIG. The output signal has nodes at rotational positions P1 and P3 and peaks at rotational positions P2 and P4. The angle θxy at the node is 270 °. The output waveform of the first element 211 is a node at rotational positions P1 and P3 in which the magnetic vector of the combined magnetic field is in the same direction (Y2 direction) as the magnetic vector of the bias magnetic field.

  In FIG. 11, the bias magnet 22 is disposed such that the N pole 22n and the S pole 22s are aligned in the X1-X2 direction with the N pole 22n on the X2 side and the boundary 22b is substantially orthogonal to the X1-X2 direction. Further, the first element 211 is disposed on the boundary 22 b, and the direction of the magnetic vector of the bias magnetic field acting on the first element 211 is the X1 direction. Also in this case, the magnetic vector of the combined magnetic field changes in accordance with the rotational positions P1 to P4 of the magnetizing rotor 10, as shown in FIG.

  In the case of the rotational position P1, the magnetic vector of the rotor magnetic field is in the Y2 direction. Therefore, the angle θxy of the magnetic vector of the combined magnetic field is larger than −90 ° and smaller than 0 °. In the case of the rotational position P2, the magnetic vector of the rotor magnetic field is in the same direction as the magnetic vector of the bias magnetic field, that is, in the X1 direction. Therefore, the magnetic vector of the combined magnetic field is obtained by adding the magnetic vector of the rotor magnetic field to the magnetic vector of the bias magnetic field, and the angle θxy of the magnetic vector of the combined magnetic field is 0 °.

  In the case of the rotational position P3, the magnetic vector of the rotor magnetic field is in the Y1 direction. Therefore, the angle θxy of the magnetic vector of the combined magnetic field is larger than 0 ° and smaller than 90 °. In the case of the rotational position P4, the magnetic vector of the rotor magnetic field is in the opposite direction to the magnetic vector of the bias magnetic field, that is, in the X2 direction. Therefore, the magnetic vector of the combined magnetic field is obtained by subtracting the magnetic vector of the rotor magnetic field from the magnetic vector of the bias magnetic field, and the angle θxy is 0 °.

  The output (signal A) of the first element 211 changes in accordance with the rotational positions P1 to P4 as shown in FIG. The output signal has nodes at rotational positions P2 and P4 and peaks at rotational positions P1 and P2. The angle θxy at the node is 0 °. The output waveform of the first element 211 is a node at rotational positions P2 and P4 in which the magnetic vector of the combined magnetic field is in the same direction (direction X1) as the magnetic vector of the bias magnetic field.

  Although illustration is omitted, the north pole 22 n and the south pole 22 s align the south pole 22 s to the Y 1 side (magnetization rotor 10 side) and align in the Y 1 -Y 2 direction, and the direction of the magnetic vector of the bias magnetic field acting on the first element 211 Is Y1, the signal of the first element 211 becomes a node at the rotational positions P1 and P3. The angle θxy at the node is 90 °. The output waveform of the first element 211 is a node at rotational positions P1 and P3 in which the magnetic vector of the combined magnetic field is in the same direction (Y1 direction) as the magnetic vector of the bias magnetic field.

  When the north pole 22n and the south pole 22s are aligned in the X1-X2 direction with the south pole 22s on the X2 side and the direction of the magnetic vector of the bias magnetic field acting on the first element 211 is the X2 direction, The signal becomes a node at rotational positions P2, P4. The angle at the node is 180 °. The output waveform of the first element 211 is a node at rotational positions P2 and P4 in which the magnetic vector of the combined magnetic field is in the same direction (X2 direction) as the magnetic vector of the bias magnetic field.

  Here, as shown in FIG. 14, the phase of the signal is defined. Then, as shown in FIGS. 8 to 10, when the angle of the magnetic vector of the bias magnetic field is 270 °, the phase of the signal at the rotational position P1 is 0 °. As shown in FIGS. 11 to 13, when the angle of the magnetic vector of the bias magnetic field is 0 °, the phase of the rotational position P1 is 270 °. Further, as described above, when the angle of the magnetic vector of the bias magnetic field is 90 °, the phase of the rotational position P1 is 180 °. When the angle of the magnetic vector of the bias magnetic field was 180 °, the phase of the rotational position P1 was 90 °.

  Summarizing the above, the relationship between the angle of the magnetic vector of the bias magnetic field acting on the first element 211 (element) and the phase of the signal at the rotational position P1 is as shown in FIG. FIG. 15 shows that the phase of the signal can be changed by changing the angle of the magnetic vector of the bias magnetic field. For example, when the angle of the magnetic vector of the bias magnetic field is changed by 90 °, the phase of the output signal of the first element 211 can be changed by 90 °.

(Arrangement of two elements)
Next, the arrangement of the first element 211 and the second element 212 and the bias magnet 22 will be described. As shown in FIG. 16, in the sensor chip 21 in the present embodiment, a first element 211 and a second element 212 are formed on the detection surface 21 d as two elements. The first element 211 and the second element 212 are arranged side by side in the X1-X2 direction with the first element 211 as the X2 side, and the center distance between these elements 211 and 212 is β. The center-to-center distance β is the distance between the centers of the V-shape, and is less than the magnetization pitch λ.

  Here, a line substantially parallel to the Y1-Y2 direction, which is the opposing direction of the magnetized surface 10m and the sensor chip 21, and along the detection surface 21d is taken as a reference line L1. The angle between the reference line L1 and the magnetic vector of the bias magnetic field acting on the first element 211 is θ1, and the angle between the reference line L1 and the magnetic vector of the bias magnetic field acting on the second element 212 is θ2. Do. In FIG. 16, in order to make the angles θ1 and θ2 easy to understand, the magnetic vector of the bias magnetic field is illustrated as being inclined with respect to the reference line L1.

  As described above, in this embodiment, the angle of the magnetic vector is indicated with the counterclockwise direction as the positive direction. Therefore, when the magnetic vector of the bias magnetic field acting on the first element 211 is inclined toward the second element 212 with respect to the reference line L1 under an environment where a magnetic field different from the bias magnetic field is not applied, the angle θ1> 0. When the second element 212 is inclined in the opposite direction, the angle θ1 <0. On the other hand, when the magnetic vector of the bias magnetic field acting on the second element 212 is inclined toward the first element 211 with respect to the reference line L1, the angle θ2 <0 is obtained, and the inclination is opposite to the first element 211. The angle θ2> 0.

  The first element 211 and the second element 212 are offset in the rotational direction of the magnetizing rotor 10, which causes a phase difference between the signals A and B (mid-point voltages A and B). The phase difference due to the arrangement of the first element 211 and the second element 212 (center distance β) is (β / α) × 360 ° in electrical angle. For example, in the case of β = λ, the phase difference is 180 °. Further, in the case of β = λ / 2, the phase difference is 90 °. Conventionally, the first element and the second element with respect to the bias magnet such that the angle of the magnetic vector of the bias magnetic field acting on the first element and the angle of the magnetic vector of the bias magnetic field acting on the second element are equal. It was arranged. For example, the first element and the second element are arranged with respect to the bias magnet such that the magnetic vector in the Y2 direction acts on each of the first element and the second element. Therefore, in the case of β <λ, there is a problem that the amplitude of the differential signal S1 becomes small.

  On the other hand, in the present embodiment, the first element 211 and the second element 212 are bias magnets in consideration of not only the phase difference due to the arrangement (center distance β) but also the phase difference due to the magnetic vector of the bias magnetic field. 22 are arranged. As described above, since the phases of the signals A and B change by the angle change of the magnetic vector of the bias magnetic field, the phase difference caused by the magnetic vector of the bias magnetic field becomes (θ1−θ2) in electrical angle. Therefore, the phase difference between the signals A and B is (β / α) × 360 ° + (θ1−θ2).

  FIG. 17 shows the relationship between the phase difference (θ1−θ2) caused by the magnetic vector of the bias magnetic field and the amplitude of the differential signal S1 of the first element 211 and the second element 212. As shown in FIG. 17, when θ1 = θ2, the amplitude of the differential signal S1 is the same as that of the conventional configuration. The amplitude of the differential signal S1 is maximum when (β / α) × 360 ° + (θ1−θ2) = 180 °. That is, the maximum value is obtained when (θ1−θ2) = 180 ° − (β / α) × 360 ° is satisfied. Here, it is defined that 180 °-(β / α) × 360 ° = θm.

  The amplitude of the differential signal S1 increases as (θ1−θ2) increases in the range of 0 ≦ (θ1−θ2) ≦ θm, and becomes maximum at (θ1−θ2) = θm. Also, in the range of θm ≦ (θ1−θ2) ≦ 2 × θm, the larger the value of (θ1−θ2), the smaller the amplitude, and (θ1−θ2) = 2 × θm, which is equal to the amplitude when θ1 = θ2 . Therefore, it is preferable to dispose the first element 211 and the second element 212 with respect to the bias magnet 22 so as to satisfy 0 <(θ1−θ2) <2 × θm. According to this, by the effect of the magnetic vector of the bias magnetic field, the amplitude of the differential signal S1 can be made larger than that of the conventional case. In particular, when the first element 211 and the second element 212 are arranged with respect to the bias magnet 22 so as to satisfy (θ1−θ2) = θm, the amplitude of the differential signal S1 can be maximized.

  FIG. 18 shows a specific signal waveform showing the effect of the magnetic vector of the bias magnetic field. The upper part of FIG. 18 shows a reference example, and the lower part shows an example of maximizing the amplitude of the differential signal S1. In the reference example, the directions of the magnetic vectors of the bias magnetic field acting on the first element 211 and the second element 212 are substantially parallel to each other. Specifically, the N pole 22 n and the S pole 22 s are arranged side by side in the Y1-Y2 direction with the N pole 22 n as the Y1 side, and the boundary 22 b is substantially orthogonal to the Y1-Y2 direction. The directions of the magnetic vectors of the bias magnetic field acting on the first element 211 and the second element 212 are both set to the Y2 direction. That is, θ1 = θ2 = 0 °. Further, the distance between centers β = λ / 2. Therefore, the phase difference between the signals A and B is 90 ° in electrical angle.

  In the same arrangement of elements as the reference example, in order to set the phase difference between the signals A and B to 180 °, (θ1−θ2) = 90 ° may be set. For example, the phase of the signal A may be advanced by 45 °, ie, −45 °, and the phase of the signal B may be delayed 45 °, ie, + 45 °. For this purpose, in the lower part of FIG. 18, the first element 211 and the second element 212 are disposed at positions where the angle θ1 = + 45 ° and the angle θ2 = −45 °. As a result, the phase difference (θ1−θ2) caused by the magnetic vector of the bias magnetic field becomes 90 °, and the phase difference between the signals A and B becomes 180 ° in electrical angle.

  3 and 19 show specific examples of the arrangement of the first element 211 and the second element 212 with respect to the bias magnet 22. FIG. In this embodiment, a rectangular flat bias magnet 22 having a length in the X1-X2 direction of 2.8 mm, a length in the Y1-Y2 direction of 1.4 mm, and a length in the Z1-Z2 direction of 0.65 mm. Is adopted. Then, in the Z1-Z2 direction, the distance from the surface of the bias magnet 22 on the side of the island 24a to the detection surface 21d of the sensor chip 21 is 0.7 mm. Arrows in FIG. 19 indicate the magnetic field distribution (magnetic simulation result) of the bias magnet 22. FIG. 19 shows, as the magnetic vector of the bias magnet 22, a position at a distance of 0.7 mm from the surface of the bias magnet 22 in the Z1-Z2 direction, that is, a vector in the same plane as the detection surface 21d.

  As shown in FIGS. 3 and 19, in the present embodiment, the N pole 22 n and the S pole 22 s are arranged side by side in the Y direction with the N pole 22 n as the Y1 side (magnetization rotor 10 side). The first element 211 and the second element 212 are disposed at positions overlapping with the south pole 22s. The first element 211 and the second element 212 are disposed at positions farther from the magnetized rotor 10 than the boundary 22 b. In the X1-X2 direction, the first element 211 and the second element 212 are disposed at positions away from the magnetic pole center line 22c. The first element 211 is disposed on the X2 side of the magnetic pole center line 22c, and the second element 212 is disposed on the X1 side of the magnetic pole center line 22c. The first element 211 and the second element 212 are arranged in line symmetry with respect to the magnetic pole center line 22c. As shown in FIG. 19, the direction of the magnetic vector acting on the first element 211 is inclined toward the second element 212, and the direction of the magnetic vector acting on the second element 212 is inclined toward the first element 211. ing.

(Arrangement of three elements)
Next, the arrangement of the third element 213, the fourth element 214, the fifth element 215, and the bias magnet 22 will be described. As shown in FIG. 20, in the sensor chip 21 in the present embodiment, a third element 213, a fourth element 214, and a fifth element 215 are formed as three elements on the detection surface 21d. The third element 213 and the fourth element 214 are arranged side by side in the X1-X2 direction with the third element 213 on the X2 side, and the center-to-center distance between these elements 213 and 214 is γ. The center-to-center distance γ is less than the magnetization pitch λ. The fifth element 215 is disposed between the third element 213 and the fourth element 214 in the X1-X2 direction.

  Here, the angle between the reference line L1 and the magnetic vector of the bias magnetic field acting on the third element 213 is θ3, and the angle between the reference line L1 and the magnetic vector of the bias magnetic field acting on the fourth element 214 is θ4. I assume. In FIG. 20, in order to make the angles θ3 and θ4 easy to understand, the magnetic vectors of the bias magnetic field are illustrated as being inclined with respect to the reference line L1. When the magnetic vector of the bias magnetic field acting on the third element 213 is inclined toward the fourth element 214 with respect to the reference line L1 under an environment where a magnetic field different from the bias magnetic field is not applied, the angle θ3> 0 is obtained. When the four elements 214 are inclined in the opposite direction, the angle θ3 <0. On the other hand, when the magnetic vector of the bias magnetic field acting on the fourth element 214 is inclined toward the third element 213 with respect to the reference line L1, the angle θ4 <0 is obtained, and the magnetic element is inclined in the opposite direction to the third element 213 The angle θ4> 0.

  The third element 213, the fourth element 214, and the fifth element 215 are disposed offset in the rotational direction of the magnetizing rotor 10. Therefore, as shown in FIG. 21, the signal C (midpoint voltage C) output from the third element 213, the signal D (midpoint voltage D) output from the fourth element 214, and the fifth element 215 A difference occurs in the phase of the output signal E (mid-point voltage E).

  Here, it is assumed that the fifth element 215 that outputs the signal E is disposed at an intermediate position between the third element 213 and the fourth element 214. When the phase difference between the signals C and D is larger than 0 ° and smaller than 180 °, as shown in FIG. 22, the signal E and the signal (C + D) have the same phase. Therefore, the smaller the amplitude of the signal (C + D), the larger the amplitude of the differential signal S2 (= 2E-C-D). When the phase difference between the signals C and D is 180 °, as shown in FIG. 23, the signals C and D have opposite phases, and the signal (C + D) becomes constant at zero. Therefore, the amplitude of the differential signal S2 is twice the value of the signal E.

  When the phase difference between the signals C and D is larger than 180 ° and smaller than 360 °, as shown in FIG. 24, the signal E and the signal (C + D) are in opposite phase. Therefore, the amplitude of the differential signal S2 increases as the amplitude of the signal (C + D) increases. When the phase difference between the signals C and D is 360 °, as shown in FIG. 25, the signal E and the signal (C + D) have opposite phases, and the signals C and D have the same phase. Therefore, the amplitude of the differential signal S2 is maximized. As described above, in order to increase the differential signal S2, it is preferable to make the phase difference between the signals C and D close to 360 °, more preferably to coincide with each other.

  The phase difference caused by the arrangement of the signals C and D (center-to-center distance γ) is (γ / α) × 360 ° in electrical angle. For example, in the case of β = λ / 2, the phase difference is 90 °. Conventionally, the third element and the fourth element relative to the bias magnet such that the angle of the magnetic vector of the bias magnetic field acting on the third element and the angle of the magnetic vector of the bias magnetic field acting on the fourth element are equal. It was arranged. For example, the third element and the fourth element are disposed with respect to the bias magnet such that the magnetic vector in the Y2 direction acts on each of the third element and the fourth element. Therefore, in the case of γ <λ, there is a problem that the amplitude of the differential signal S2 is small.

  On the other hand, in the present embodiment, not only the phase difference due to the arrangement (center-to-center distance γ) but also the phase difference due to the magnetic vector of the bias magnetic field are taken into consideration. Is placed against. As described above, since the phases of the signals C and D change by the angle change of the magnetic vector of the bias magnetic field, the phase difference caused by the magnetic vector of the bias magnetic field becomes (θ3−θ4) in electrical angle. Therefore, the phase difference between the signals C and D is (γ / α) × 360 ° + (θ3−θ4).

  FIG. 26 shows the relationship between the phase difference (θ3-θ4) caused by the magnetic vector of the bias magnetic field and the amplitude of the differential signal S2. When θ3 = θ4, the amplitude of the differential signal S2 is the same as in the conventional configuration. As shown in FIG. 26, the amplitude of the differential signal S2 is maximum when (γ / α) × 360 ° + (θ3−θ4) = 360 ° is satisfied. That is, the maximum value is obtained when (θ3−θ4) = 360 ° − (γ / α) × 360 ° is satisfied. Here, it is defined that 360 °-(γ / α) × 360 ° = θn.

  The amplitude of the differential signal S2 increases as (θ3−θ4) increases in the range of 0 ≦ (θ3−θ4) ≦ θn, and becomes maximum at (θ3−θ4) = θn. Also, in the range of θm ≦ (θ3−θ4) ≦ 2 × θn, it decreases as (θ3−θ4) increases and becomes equal to the amplitude at θ3 = θ4 with (θ3−θ4) = 2 × θm . Therefore, it is preferable to dispose the third element 213 and the fourth element 214 with respect to the bias magnet 22 so as to satisfy 0 <(θ3−θ4) <2 × θn. According to this, by the effect of the magnetic vector of the bias magnetic field, the amplitude of the differential signal S2 can be made larger than that of the conventional case. In particular, when the third element 213 and the fourth element 214 are arranged with respect to the bias magnet 22 so as to satisfy (θ3−θ4) = θn, the amplitude of the differential signal S2 can be further increased.

  FIG. 27 shows a specific signal waveform showing the effect of the magnetic vector of the bias magnetic field. The upper part of FIG. 27 shows a reference example, and the lower part shows an example in the case of maximizing the amplitude of the differential signal S2. In the reference example, the directions of the magnetic vectors of the bias magnetic field acting on the third element 213 and the fourth element 214 are substantially parallel to each other. Specifically, the N pole 22 n and the S pole 22 s are arranged side by side in the Y1-Y2 direction with the N pole 22 n as the Y1 side, and the boundary 22 b is substantially orthogonal to the Y1-Y2 direction. The directions of the magnetic vectors of the bias magnetic field acting on the third element 213 and the fourth element 214 are both set to the Y2 direction. That is, θ3 = θ4 = 0 °. Further, the center-to-center distance γ = λ / 2. Therefore, the phase difference between the signals C and D is 90 ° in electrical angle.

  In the same element arrangement as the reference example, in order to make the phase difference between the signals C and D 360 °, (θ3−θ4) = 270 °. For example, the phase of the signal C may be advanced by 135 °, ie, −135 °, and the phase of the signal D may be delayed by 135 °, ie, + 135 °. For this purpose, in the lower part of FIG. 27, the third element 213 and the fourth element 214 are disposed at positions where the angle θ3 = + 135 ° and the angle θ4 = -135 °. Thereby, the phase difference (θ3-θ4) caused by the magnetic vector of the bias magnetic field is 270 °, and the phase difference of the signals C and D is 360 ° in electrical angle.

  3 and 19 show specific examples of the arrangement of the third element 213, the fourth element 214, and the fifth element 215 with respect to the bias magnet 22. FIG. As shown in FIGS. 3 and 19, in the present embodiment, the third element 213 and the fourth element 214 are disposed at positions overlapping the south pole 22 s. The third element 213 and the fourth element 214 are disposed at positions farther from the magnetized rotor 10 than the boundary 22 b. In the X1-X2 direction, the third element 213 and the fourth element 214 are disposed at positions away from the magnetic pole center line 22c. The third element 213 is disposed on the X2 side of the magnetic pole center line 22c, and the fourth element 214 is disposed on the X1 side of the magnetic pole center line 22c. The third element 213 and the fourth element 214 are arranged in line symmetry with respect to the magnetic pole center line 22c. As shown in FIG. 19, the direction of the magnetic vector acting on the third element 213 is inclined to the fourth element 214 side, and the direction of the magnetic vector acting on the fourth element 214 is inclined to the third element 213 side ing.

  The bias magnet 22 has two corner portions 22r1 and 22r2 on the opposite side to the magnetizing rotor 10, that is, on the Y2 side of the boundary 22b. The corner 22 r 1 is provided on the X 2 side, and the corner 22 r 2 is provided on the X 1 side. As shown in FIG. 19, as the magnetic vectors of the bias magnetic field approach the corner portions 22r1 and 22r2, the inclination with respect to the reference line L1 increases. The third element 213 is disposed at a position closer to the corner 22 r 1 than the first element 211 disposed on the X 2 side. Thus, θ3> θ1. In addition, the fourth element 214 is disposed at a position closer to the corner 22r2 than the second element 212 disposed on the X1 side. Thus, θ4 <θ2 is satisfied. The absolute value of θ4 is larger than the absolute value of θ2.

  The fifth element 215 is disposed at a position overlapping the N pole 22 n. The fifth element 215 is disposed at a position closer to the magnetized rotor 10 than the boundary 22 b. The fifth element 215 is disposed at a position closer to the magnetized rotor 10 than the third element 213 and the fourth element 214. The fifth element 215 is disposed on the magnetic pole center line 22c. Thus, the direction of the magnetic vector acting on the fifth element 215 is the Y2 direction. The fifth element 215 is disposed between the third element 213 and the fourth element 214 in the X1-X2 direction. The fifth element 215 is disposed at an intermediate position between the third element 213 and the fourth element 214. The third element 213, the fourth element 214, and the fifth element 215 are arranged in line symmetry with respect to the magnetic pole center line 22c.

  Next, the effects of the rotation detection device 20 shown in the present embodiment will be described.

  In the present embodiment, the first element 211 and the second element 212 are arranged with respect to the bias magnet 22 so as to satisfy 0 <(θ1−θ2) <2 × {180 ° − (β / α) × 360 °}. It is done. Therefore, due to the effect of the magnetic vector of the bias magnetic field, the amplitude of the differential signal S1 can be made larger than in the prior art.

  In particular, the first element 211 and the second element 212 are arranged with respect to the bias magnet 22 so as to satisfy (β / α) × 360 ° + (θ1−θ2) = 180 °. As a result, the phase difference between the signals A and B becomes 180 ° in electrical angle. Therefore, it is possible to maximize the amplitude of the differential signal S1 while satisfying the condition β <λ to miniaturize the physical size of the rotation detection device 20.

  In the present embodiment, the fifth element 215 is disposed between the third element 213 and the fourth element 214. Then, the third element 213 and the fourth element 214 are arranged with respect to the bias magnet 22 so as to satisfy 0 <(θ3−θ4) <2 × {360 ° − (γ / α) × 360 °}. . According to this, by the effect of the magnetic vector of the bias magnetic field, it is possible to make the amplitude of the differential signal S2 larger than that of the prior art.

  In particular, the third element 213 and the fourth element 214 are arranged with respect to the bias magnet 22 so as to satisfy (γ / α) × 360 ° + (θ3−θ4) = 360 °. As a result, the phase difference between the signals C and D becomes 360 ° in electrical angle. Therefore, the amplitude of the differential signal S2 can be further increased while the size of the rotation detection device 20 is miniaturized while satisfying γ <λ.

  Note that the fifth element 215 may be disposed at least between the third element 213 and the fourth element 214. Preferably, the fifth element 215 is disposed at an intermediate position between the third element 213 and the fourth element 214 and on the magnetic pole center line 22c. According to this, the third element 213 and the fourth element 214 are arranged in line symmetry with respect to the magnetic pole center line 22c, and the peak of the signal (C + D) coincides with the peak of the signal E. Therefore, the amplitude of differential signal S2 can be further increased. In particular, when (γ / α) × 360 ° + (θ3−θ4) = 360 °, the amplitude of the differential signal S2 can be maximized.

  In the present embodiment, the fifth element 215 is disposed at a position closer to the magnetized rotor 10 than the boundary 22 b. Thereby, detection sensitivity can be improved.

  The arrangement of the sensor chips 21 (elements 211 to 215) with respect to the bias magnet 22 may use, for example, magnetic simulation (magnetic field distribution) shown in FIG. The magnetic field distribution at the position of the detection surface 21 d in an environment where a magnetic field different from the bias magnetic field is not applied may be obtained, and the positions of the elements 211 to 215 may be determined from the result.

  In the present embodiment, the rotation detection device 20 includes only one bias magnet 22, and the N pole 22 n and the S pole 22 s are arranged side by side in the opposing direction with the magnetizing surface 10 m of the magnetizing rotor 10. . According to this, it is possible to reduce the number of parts and to miniaturize the physical size of the rotation detection device 20 while achieving the effects described above. Further, since the sensor chip 21 may be positioned and disposed with respect to one bias magnet 22, the positional accuracy of each of the elements 211-215 with respect to the bias magnet 22 can be improved.

Second Embodiment
This embodiment can refer to the preceding embodiments. Therefore, the description of the portions common to the rotation detection device 20 shown in the preceding embodiment will be omitted.

  The rotation detection device 20 according to this embodiment includes three elements as the magnetoresistance effect element 210, specifically, the third element 213, the fourth element 214, and the fifth element 215, as in the preceding embodiment. And it is comprised so that the influence of an external magnetic field can be canceled more effectively.

  First, the influence of the external magnetic field on the three elements will be described with reference to FIG.

  In FIG. 28, the magnetic vector of the bias magnetic field acting on the magnetoresistance effect element 210 is indicated by a broken arrow, and the magnetic vector of the external magnetic field acting on the magnetoresistance effect element 210 is indicated by a dashed dotted arrow. A magnetic vector of a combined magnetic field of the bias magnetic field and the external magnetic field is indicated by a solid arrow. The three elements receive an external magnetic field whose magnitude and direction are substantially equal to one another. In addition, the change in angle from the magnetic vector of the bias magnetic field to the magnetic vector of the combined magnetic field is indicated by Δθ by the action of the external magnetic field. Δθ c represents an angle change in the third element 213, Δθ d represents an angle change in the fourth element 214, and Δθ e represents an angle change in the fifth element 215.

  As described above, the differential signal S2 of the three elements is 2E- (C + D). For this reason, when the relationship of 2 × Δθe = Δθc + Δθd is established for the angle change, the influence of the external magnetic field can be effectively canceled.

  However, in the present embodiment, the fifth element 215 is disposed closer to the third element 213 and the fourth element 214 with respect to the magnet center 22 d which is the center of the bias magnet 22. The magnet center 22d, that is, the magnet center is an intersection point of the boundary 22b and the pole center line 22c. In addition, since the bias magnet 22 is small due to integration, it has a magnetic force distribution in the XY plane. Therefore, the magnetic vector of the bias magnetic field is larger in the fifth element 215 than in the third element 213 and the fourth element 214. Since the magnetic vector of the bias magnetic field acting on the fifth element 215 is large, the angle change of the magnetic vector of the combined magnetic field also reduces Δθe. Therefore, if, for example, the magnetoresistance effect element 210 having the same configuration is used as the three elements, 2 × Δθe <Δθc + Δθd.

  Next, a configuration capable of effectively canceling the influence of the external magnetic field will be described based on FIG. 29 and FIG.

  In the present embodiment, as shown in FIG. 29, two types of magnetoresistance effect elements 210 are used. Specifically, the high sensitivity element 210H shown in FIG. 29 (a) and the low sensitivity element 210L shown in FIG. 29 (b) are used.

  The magnetoresistive effect element 210 is formed to have a meander shape (serpentine shape) using, for example, a Ni--Fe-based material or a Ni--Co-based material. In meander shape, assuming that the extended longitudinal portion is a positive sensitivity portion 210a having positive sensitivity, a folded portion connecting the positive sensitivity portions 210a is substantially orthogonal to the longitudinal direction, and is a negative sensitivity portion having negative sensitivity. It becomes 210b. The folded portion has a short extension length relative to the longitudinal portion. FIG. 29 is a plan view, but hatching is performed to distinguish between the positive sensitivity section 210a and the negative sensitivity section 210b.

  Most of the high sensitivity element 210H is occupied by the positive sensitivity section 210a. The plurality of longitudinal portions constituting the positive sensitivity portion 210a are juxtaposed at a predetermined pitch so that the longitudinal directions are substantially parallel to each other. And the negative sensitivity part 210b is provided between the both ends of the adjacent positive sensitivity part 210a. The negative sensitivity portion 210b is extended in the lateral direction of the positive sensitivity portion 210a. The other end of the high sensitivity element 210H is provided at the opposite position in the short direction.

  In the present embodiment, the negative sensitivity portion 210b is shorted by, for example, an Al wiring (not shown). That is, the end portions of adjacent positive sensitivity portions 210a are electrically connected by Al wiring. As a result, the high sensitivity element 210H has sensitivity characteristics similar to those of the configuration that does not substantially have the negative sensitivity portion 210b.

  The low sensitivity element 210L has a smaller ratio of the positive sensitivity portion 210a than the high sensitivity element 210H, that is, the ratio of the negative sensitivity portion 210b is increased. Specifically, one end and the other end of the low sensitivity element 210L are disposed on the same side in the lateral direction. The meander-shaped portion connected to one end and the meander-shaped portion connected to the other end are integrally connected on the opposite side to the both ends in the short direction. As described above, by providing the meander-shaped portions on both end sides, the ratio of the folded portion, that is, the negative sensitivity portion 210b is increased.

  In the low-sensitivity element 210L, the extension length in the short direction of the portion connecting the two meander-shaped portions is further longer than that of the folded portion. Also in this case, the proportion of the negative sensitivity portion 210b is increased. Then, in the low sensitivity element 210L, like the high sensitivity element 210H, the connection by the Al wiring is not performed. Thus, the low sensitivity element 210L has a lower sensitivity than the high sensitivity element 210H.

  FIG. 30 shows the arrangement of the magnetoresistive effect element 210 with respect to the bias magnet 22 in the rotation detection device 20 of this embodiment. The arrangement of the third element 213, the fourth element 214, and the fifth element 215 is the same as in the preceding embodiment (see three elements shown in FIG. 19). It differs from the preceding embodiment in that a low sensitivity element 210L is used as the third element 213 and the fourth element 214, and a high sensitivity element 210H is used as the fifth element 215.

  The third element 213 is configured to include the four low sensitivity elements 210L described above. The four low sensitivity elements 210L are connected in series between the power supply (Vcc) and the ground (GND). Specifically, two low sensitivity elements 210L are connected in series on the power supply side (high side), and another two low sensitivity elements 210L are connected in series on the ground side (low side). The midpoint voltage C is output from the connection point of the second and third low sensitivity elements 210L.

  The two low sensitivity elements 210L on the high side are provided such that the longitudinal directions are parallel to each other. The two low sensitivity side low sensitivity elements 210L are provided such that the longitudinal directions are parallel to each other, and the longitudinal directions are orthogonal to the longitudinal direction on the high side. One low-sensitivity element 210L on the high side and one low-sensitivity element 210L on the low side are arranged to form a V shape, and the third element 213 has two pairs of V shapes. ing. The fourth element 214 has the same configuration as the third element 213. The midpoint voltage D is output from the connection point of the second and third low sensitivity elements 210L.

  The fifth element 215 is configured to include the four high sensitivity elements 210H described above. The four high sensitivity elements 210H are connected in series between the power supply (Vcc) and the ground (GND). Specifically, two high sensitivity elements 210H are connected in series on the power supply side (high side), and another two high sensitivity elements 210H are connected in series on the ground side (low side). The midpoint voltage E is output from the connection point of the second and third high sensitivity elements 210H.

  The two high sensitivity elements 210H on the high side are provided such that the longitudinal directions are parallel to each other. The two high sensitivity elements 210H on the low side are provided such that the longitudinal directions are parallel to each other, and the longitudinal directions are orthogonal to the longitudinal direction on the high side. One high sensitivity side element 210H on the high side and one high sensitivity element 210H on the low side are arranged in a V shape, and the fifth element 215 has two pairs of V shapes. ing.

  As described above, in the present embodiment, the fifth element 215 close to the magnet center 22d is the high sensitivity element 210H, and the third element 213 and the fourth element 214 far from the magnet center 22d are the low sensitivity element 210L. . As described above, since the sensitivity is intentionally made different in the three elements, 2 × Δθe can be approximately equal to Δθc + Δθd. Therefore, even if an external magnetic field acts, the fluctuation of differential signal S2 by it can be suppressed. That is, the resistance of the external magnetic field can be improved.

  In the present embodiment, the fifth element 215 is closer to the magnet center 22 d than the third element 213 and the fourth element 214. When the third element 213 and the fourth element 214 are closer to the magnet center 22 d than the fifth element 215, 2 × Δθe> Δθc + Δθd. Therefore, the high sensitivity element 210H may be used as the third element 213 and the fourth element 214, and the low sensitivity element 210L may be used as the fifth element 215.

  The configurations of the high sensitivity element 210H and the low sensitivity element 210L are not limited to the above examples. The high sensitivity element 210H may be relatively high in sensitivity to the low sensitivity element 210L, and the low sensitivity element 210L may be relatively low in sensitivity to the high sensitivity element 210H.

  In the present embodiment, the rotation detection device 20 has an example in which only three elements are provided as the magnetoresistance effect element 210, but the present invention is not limited to this. As in the previous embodiment, in addition to the three elements, a first element 211 and a second element 212 may be provided. As described above, from the midpoint voltage A of the first element 211 and the midpoint voltage B of the second element 211, (A−B) is generated as the differential signal S1. Therefore, as the first element 211 and the second element 212 arranged in line symmetry, it is preferable to use the high sensitivity element 210H.

  The disclosure of this specification is not limited to the illustrated embodiments. The disclosure includes the illustrated embodiments and variations based on them by those skilled in the art. For example, the disclosure is not limited to the combination of elements shown in the embodiments. The disclosure can be implemented in various combinations. The disclosed technical scope is not limited to the description of the embodiments. The technical scopes disclosed are set forth by the description of the claims, and should be understood to include all the modifications within the meaning and scope equivalent to the descriptions of the claims. .

  Although the rotation detection apparatus 20 showed the example sealed by the sealing resin body 25 and carrying out mold packaging, it is not limited to this. For example, the sensor chip 21 or the circuit chip 23 may be fixed on one surface of a substrate such as a ceramic substrate or a printed substrate, and the bias magnet 22 may be fixed on the back surface of the substrate.

  Although the differential amplifier 230-233 as a differential part showed the example formed in the circuit chip 23, it is not limited to this. The differential amplifiers 230-233 may be integrated into the sensor chip 21.

  Although the rotation detection apparatus 20 showed the example which has the threshold value production | generation part 234, the comparators 235 and 236, and the determination part 237 in the circuit chip 23, it is not limited to this. The threshold value generation unit 234, the comparators 235 and 236, and the determination unit 237 may be integrated on the sensor chip 21 together with the differential amplifiers 230 to 233. In addition, the configuration in which the rotation detection device 20 does not have the threshold generation unit 234, the comparators 235 and 236, and the determination unit 237, specifically, another electronic device is the threshold generation unit 234, the comparators 235 and 236, and the determination unit 237 may be included.

  Although the example which makes (E-C)-(D-E) = 2E- (C + D) differential signal S2 was shown, it is not limited to this. The differential signal S2 may be a differential signal generated from the outputs of the third element 213, the fourth element 214, and the fifth element 215 which are three elements. The influence of the external magnetic field can be canceled by (EC), and the influence of the external magnetic field can be canceled by (DE).

  Although the rotation detection apparatus 20 has shown the example which has the 1st element 211, the 2nd element 212, the 3rd element 213, the 4th element 214, and the 5th element 215 as the magnetoresistive effect element 210, it is limited to this I will not. For example, only the first element 211 and the second element 212 may be provided. Further, only the third element 213, the fourth element 214, and the fifth element 215 may be provided. In any case, information indicating the rotational position of the magnetizing rotor 10 can be output.

  In a configuration having only the third element 213, the fourth element 214, and the fifth element 215, the differential signal S1 is generated from the outputs of the third element 213 and the fourth element 214, and the third element 213, the fourth element The differential signal S2 can also be generated from the outputs of the 214 and the fifth element 215. That is, three elements can be used to output information indicating the rotational position of the magnetizing rotor 10 and information indicating the rotational direction of the magnetizing rotor 10. However, since the third element 213 and the fourth element 214 are used both as two elements for generating the differential signal S1 and as elements at both ends for generating the differential signal S2, for example, the differential signal S1 is used. , S2 can not both be maximized. According to the configuration shown in the present embodiment, since the first element 211 and the second element 212 and the third element 213 and the fourth element 214 can be arranged individually, the differential signals S1 and S2 are more than in the case of dual use. It is possible to increase the amplitude of

  In addition to the first element 211 and the second element 212, another magnetoresistive element 210 may be provided, and in addition to the third element 213, the fourth element 214, and the fifth element 215, another element may be provided. The magnetoresistance effect element 210 may be provided. In addition to the first element 211, the second element 212, the third element 213, the fourth element 214, and the fifth element 215, another magnetoresistive element 210 may be included.

  Although the example in which the threshold value generation unit 234 supplies the threshold value Vth to the comparators 235 and 236 is described in the present embodiment, the present invention is not limited thereto. For example, a threshold may be set for each of the comparators 235 and 236.

  The arrangement of the first element 211 and the second element 212, which are two elements from which the differential signal S1 is generated, is not limited to the above example. Further, the arrangement of the third element 213, the fourth element 214, and the fifth element 215, which are three elements from which the differential signal S2 is generated, is not limited to the above example. As shown in FIG. 19, in the vicinity of the magnetic pole center line 22c and the boundary 22b, the direction of the magnetic vector of the bias magnetic field is substantially along the Y2 direction. Further, at a position farther from the magnetized rotor 10 than the boundary 22b, the magnetic vector is directed toward the magnetic pole center line 22c. Therefore, the first element 211, the second element 212, the third element 213, and the fourth element 214 are positions farther from the magnetized rotor 10 than the boundary 22b and near the magnetic pole center line 22c and the boundary 22b. It is good to arrange in the position except.

  For example, as in the modification shown in FIG. 31, at least one of the first element 211, the second element 212, the third element 213, the fourth element 214, and the fifth element 215 is not overlapped with the bias magnet 22. It may be arranged. Such an arrangement is possible, for example, by making the sensor chip 21 larger than the bias magnet 22. In FIG. 31, the third element 213 and the fourth element 214 are disposed at positions not overlapping the bias magnet 22. The third element 213 is disposed outside the corner 22r1, and the inclination of the acting magnetic vector is larger than that near the corner 22r1. Similarly, the fourth element 214 is disposed outside the corner 22r2, and the inclination of the acting magnetic vector is larger than the vicinity of the corner 22r2. According to this, even if the center distance γ can not be increased, it is possible to make the phase difference between the signals C and D closer to 360 °.

  Although an example in which the N pole 22 n is on the magnetizing rotor 10 side and the N pole 22 n and the S pole 22 s are arranged side by side in the Y1-Y2 direction as the bias magnet 22 is shown, the invention is not limited thereto. For example, the bias magnet 22 in which the N pole 22 n and the S pole 22 s are arranged side by side in the X1-X2 direction can also be adopted. In addition, it is also possible to adopt a bias magnet 22 disposed so that the alignment direction of the N pole 22 n and the S pole 22 s, in other words, the pole center line 22 c is inclined with respect to the Y1-Y2 direction and the X1-X2 direction.

  In addition, by using a plurality of bias magnets 22, the direction of the magnetic vector of the bias magnetic field acting on each of the elements 211 to 215 may be optimized. For example, with respect to the third element 213 and the fourth element 214, bias magnets 22 having different arrangement directions of the N pole 22n and the S pole 22s may be used individually.

  Although the angle of the magnetic vector has been defined with the counterclockwise direction as the positive direction, it is not limited thereto. The clockwise direction may be a positive direction. For example, in the case of two elements, the first element 211 is disposed on the X1 side, and the second element 212 is disposed on the X2 side.

  In the magnetizing rotor 10, the outer peripheral end face (side surface) orthogonal to the rotation axis is the magnetizing surface 10m, and the rotation detector 20 is disposed to face the magnetizing surface 10m. However, the present invention is not limited thereto. As in the modification shown in FIG. 32, one of the annular surfaces may be a magnetized surface 10 m instead of the outer peripheral end surface, and the rotation detecting device 20 may be disposed opposite to the magnetized surface 10 m.

DESCRIPTION OF SYMBOLS 10 Magnetization rotor 10m Magnetization surface 10n N pole 10s S pole 20 Rotation detection device 21 Sensor chip 21d Detection surface 210 Magnetoresistance effect element 210a Positive sensitivity portion 210b: negative sensitivity portion 210H: high sensitivity element 210L: low sensitivity element 211: first element 212: second element 213: third element 214: fourth element 215: fifth element 22 ... Bias magnet, 22b ... boundary, 22c ... pole center line, 22d ... magnet center, 22n ... N pole, 22r 1, 22r 2 ... corner, 22s ... S pole, 23 ... circuit chip, 230 to 233 ... differential amplifier, 234 ... threshold generation unit, 235, 236 ... comparator, 237 ... determination unit, 24 ... lead frame, 24a ... island, 24b to 24d ... terminal, 25 ... sealing resin body, 26 ... bonding wire, 2 ... output terminal, 28 ... power supply terminal, 29 ... ground terminal, L1 ... reference line

Claims (9)

A rotation detection device for detecting the rotational state of a magnetized rotor (10) having a magnetized surface (10 m) in which magnetization poles λ and magnetization cycles α and N and S poles are alternately magnetized in the rotational direction There,
A detection surface (21d) orthogonal to the magnetizing surface, and a plurality of magnetoresistance effect elements (210) formed on the detection surface, the resistance value of which changes with the rotation of the magnetizing rotor; A sensor chip including, as the magnetoresistive effect element, a first element (211), and a second element (212) arranged such that a center distance β with the first element is less than the magnetization pitch λ (21),
At least one bias magnet (22) for applying a bias magnetic field to the plurality of magnetoresistive elements;
A differential unit (230) that generates a differential signal from the outputs of the first element and the second element;
Equipped with
The angle between the reference line (L1) parallel to the opposing direction of the sensor chip and the magnetized surface and along the detection surface and the magnetic vector of the bias magnetic field acting on the first element is θ1 When an angle between the reference line and the magnetic vector of the bias magnetic field acting on the second element is θ2,
In an environment where a magnetic field different from the bias magnetic field is not applied,
A magnetic vector acting on the first element is inclined toward the second element with respect to the reference line to be θ1> 0, and a magnetic vector acting on the second element is the first element relative to the reference line It is inclined to the side and θ2 <0, and
2 × {180 ° − (β / α) × 360 °}>(θ1−θ2)> 0
A rotation detection device in which the first element and the second element are disposed with respect to the bias magnet so as to satisfy the following. The first element and the second element are
(Β / α) × 360 ° + (θ1−θ2) = 180 °
The rotation detection device according to claim 1, wherein the rotation detection device is disposed with respect to the bias magnet so as to satisfy A rotation detection device for detecting the rotational state of a magnetized rotor (10) having a magnetized surface (10 m) in which magnetization poles λ and magnetization cycles α and N and S poles are alternately magnetized in the rotational direction There,
A detection surface (21d) orthogonal to the magnetizing surface, and a plurality of magnetoresistance effect elements (210) formed on the detection surface, the resistance value of which changes with the rotation of the magnetizing rotor; As the magnetoresistive effect element, a third element (213), a fourth element (214) arranged so that a center-to-center distance γ to the third element is smaller than the magnetization pitch λ, and the third element A sensor chip (21) including a fifth element (215) disposed between the first element and the fourth element;
At least one bias magnet (22) for applying a bias magnetic field to the plurality of magnetoresistive elements;
A differential unit (231, 232, 233) that generates a differential signal from the output of the third element, the fourth element, and the fifth element;
Equipped with
The angle between the reference line (L1) parallel to the opposing direction of the sensor chip and the magnetized surface and along the detection surface and the magnetic vector of the bias magnetic field acting on the third element is θ3 When an angle between the reference line and the magnetic vector of the bias magnetic field acting on the fourth element is θ4,
In an environment where a magnetic field different from the bias magnetic field is not applied,
A magnetic vector acting on the third element is inclined toward the fourth element with respect to the reference line to be θ3> 0, and a magnetic vector acting on the fourth element is the third element relative to the reference line It is inclined to the side and it is made θ4 <0,
2 × {360 ° − (γ / α) × 360 °}>(θ3−θ4)> 0
The rotation detecting device according to claim 3, wherein the third element and the fourth element are disposed with respect to the bias magnet so as to satisfy the following. The third element and the fourth element are
(Γ / α) × 360 ° + (θ3-θ4) = 360 °
The rotation detection device according to claim 3, wherein the rotation detection device is disposed with respect to the bias magnet so as to satisfy   5. The rotation detection device according to claim 3, wherein the fifth element is disposed at an intermediate position between the third element and the fourth element and on the center line of the magnetic pole of the bias magnet. The fifth element is disposed at a position closer to the center (22d) of the bias magnet than the third element and the fourth element,
The rotation detection device according to any one of claims 3 to 5, wherein the sensitivities of the third element and the fourth element are lower than the sensitivity of the fifth element. The third element and the fourth element are disposed closer to the center (22d) of the bias magnet than the fifth element,
The rotation detection device according to any one of claims 3 to 5, wherein the sensitivity of the fifth element is lower than the sensitivity of the third element and the fourth element. Equipped with one bias magnet,
The rotation detection device according to any one of claims 1 to 7, wherein an N pole and an S pole of the bias magnet are aligned in the opposite direction.   The rotation detection device according to any one of claims 1 to 8, further comprising a sealing resin body (25) that integrally seals the sensor chip, the bias magnet, and the differential portion.