JP4487807B2 - Rotation detector - Google Patents

Description

  The present invention relates to a rotation detection device that uses a magnetic detection element such as a magnetoresistive element or a Hall element to detect the rotation mode of a magnetic rotor disposed in the vicinity thereof.

  Conventionally, as this type of rotation detection device, for example, a device described in Patent Document 1 is known. FIG. 6 shows a planar structure of a rotation detection device that is generally employed conventionally as a rotation detection device such as a crank angle sensor of an engine, including the rotation detection device described in Patent Document 1.

  As shown in FIG. 6, in this rotation detection device, a semiconductor chip 11 including a magnetoresistive element pair M11 composed of magnetoresistive elements MRE1 and MRE2 and a magnetoresistive element pair M12 composed of magnetoresistive elements MRE3 and MRE4 is provided. The sensor chip (mold IC) 12 is configured by being integrated and molded and sealed together with the signal processing circuit. The sensor chip 12 is mounted in a hollow portion 14 provided for the bias magnet 13 and is disposed so as to face the magnetic rotor RT as a detection target with a gap G therebetween. Yes. Inside the sensor chip 12, the semiconductor chip 11 is mounted on one end of a lead frame, and terminals such as a power supply terminal T1, an output terminal T2, and a ground (ground) terminal T3 are drawn from the other end. .

  FIG. 7A is a perspective view showing details of the internal structure of the sensor main body configured to include the sensor chip 12, the bias magnet 13, and the like. FIG. 7B shows a detailed plan view of the bias magnet 13 in particular. The arrow in FIG. 7B indicates the direction of the bias magnetic field (exactly its magnetic vector) generated from the bias magnet 13.

  As shown in FIG. 7 (a), the sensor body 10 is formed in a through hole made of a rectangular column (plate) provided in the longitudinal direction of a cylindrical bias magnet 13, that is, in the hollow portion 14. The chip 12 is accommodated and is fixed at a predetermined position with, for example, an adhesive. Further, as shown in detail in FIG. 7B, the bias magnet 13 has a cylindrical shape composed of column surfaces symmetrically arranged with respect to the hollow portion 14, that is, point-symmetric with respect to the hollow portion 14. It has a columnar shape with equal wall thickness. As the bias magnet 13, a magnet obtained by mixing and solidifying magnetic powder and resin is generally used because of its moldability.

In the rotation detecting device having such a configuration, the magnetoresistive elements MRE1 and MRE2 constituting the magnetoresistive element pair M11 and the magnetoresistive elements MRE3 and MRE4 constituting the magnetoresistive element pair M12 constitute a half bridge circuit, respectively. Yes. Then, after various processing such as differential amplification and binarization is performed by the signal processing circuit on the change of each midpoint potential of the half-bridge circuit, this electric signal is taken out through the output terminal T2. That is, when the rotor RT rotates, the magnetic vector changes in the bias magnetic field applied to the magnetoresistive element pair M11 and M12. At this time, the change in the magnetic vector is detected as a change in the resistance value of the magnetoresistive elements MRE1 to MRE4, and an electric signal corresponding to the change in the magnetic vector is output from the sensor chip 12. Thereby, the rotation mode of the rotor RT is obtained from the electric signal.
JP 2001-116815 A

  By the way, the electric signal (signal waveform) output from the sensor chip 12 has a larger amplitude as the distance (gap) between the sensor chip 12 and the rotor RT is shorter. For this reason, if this gap is set small, even if the magnetic vector change of the bias magnetic field is small, it can be detected. However, conventionally, when this gap is made small, there is a problem that the accuracy of rotation detection is reduced. The inventor found out that the cause of this is the installation environment of the rotation detection device.

  That is, for example, in a rotation detection device used as an engine crank angle sensor, in addition to the rotor RT, for example, a counterweight of a crankshaft, a ring gear of a flywheel, a bolt for fixing various parts, etc. Various magnetic members (peripheral magnetic bodies) made of a ferromagnetic material such as iron are disposed around the sensor chip 12. For this reason, the reference angle of the magnetic vector acting on the magnetoresistive elements MRE1 to MRE4 may change under the influence of such peripheral magnetic material. For example, as shown in FIG. 8, when a peripheral magnetic body MT is disposed around the sensor chip 12 (not shown), a bias magnetic field generated from the bias magnet 13 is generated as shown by a broken line arrow in the figure. It is attracted not only to the rotor RT (also not shown) but also to the peripheral magnetic body MT. Thus, the rotation taken out through the terminals T1 and T2 (FIG. 6) due to the change in the reference angle of the magnetic vector acting on the magnetoresistive elements MRE1 to MRE4, which causes an unnecessary offset in each of the midpoint potentials. The reliability of information was reduced.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a rotation detection device capable of detecting rotation of a rotor that is a detection target while maintaining high accuracy without depending on an installation environment. And

  In order to achieve such an object, in the invention according to claim 1, a sensor chip including a magnetic detection element is attached to a hollow portion provided for a bias magnet that applies a bias magnetic field to the magnetic detection element, and In a rotation detection device for detecting a rotation mode of the rotor by detecting a change in a magnetic vector generated in the bias magnetic field when the magnetic rotor rotates in the vicinity of the sensor chip and detecting the rotation mode of the rotor. In addition, another magnetic body (peripheral magnetic body) is disposed for an arbitrary purpose, and the bias magnet has a shape that is selectively thinned at least on the magnetic body side disposed in the vicinity of the rotor. It is set as the structure arrange | positioned.

  According to such a configuration as the rotation detection device, the bias magnet is selectively thinned so that the bias toward the peripheral magnetic body disposed for any purpose in the vicinity of the rotor that is the detection target is provided. The amount of magnetic field shake is suppressed. In other words, even in an installation environment having a peripheral magnetic body in the vicinity of the rotor that is the detection target, the influence from the peripheral magnetic body is naturally suppressed, and the accuracy of rotation detection and thus the reliability of the detection Will be kept high.

  Further, in this case, as to the selective thinning of the bias magnet, as in the invention according to claim 2, at least the rotor with respect to a quadrangular prism shape which is a reference shape of the hollow portion provided in the bias magnet. It is effective to be realized by curving the column surface facing the magnetic body (peripheral magnetic body) disposed in the vicinity to the outside in a convex shape.

  In general, including the rotation detection device shown in FIG. 6, a sensor chip (for example, a mold IC) including a magnetic detection element has a quadrangular prism (plate) shape. For this reason, as the hollow part of the bias magnet that accommodates the same, a hollow part having a quadrangular prism shape is adopted. Therefore, as in the above configuration, if the column surface of the hollow portion facing at least the peripheral magnetic body is curved outward, the wall thickness of the bias magnet on the peripheral magnetic body side is increased. It will be thinned selectively. That is, according to such a configuration, selective thinning of the bias magnet can be realized more easily.

Further, the selective thinning of the bias magnet is performed, for example, according to the invention of claim 3,
A cylinder or regular polygonal column shape used as a reference shape of the bias magnet is realized based on at least a column surface facing a magnetic body disposed in the vicinity of the rotor being flattened.
Alternatively, as in the invention according to claim 4,
-Realized on the basis of the formation of one or more cuts (slits) on at least the magnetic body disposed near the rotor of the bias magnet.
If this configuration is adopted, selective thinning of the bias magnet can be easily realized without changing the shape of the hollow portion of the bias magnet.

  Further, according to the invention described in claim 5, in the rotation detection device according to any one of claims 1 to 4, the bias magnet is symmetrical with respect to a hollow portion provided in the bias magnet. By having a column shape composed of arranged column surfaces, a magnetic field is symmetrically applied from the periphery to the hollow portion of the bias magnet, and thus to a sensor chip (for example, a mold IC) mounted thereon. become. In other words, such a configuration is particularly effective in maintaining higher rotation detection accuracy.

  On the other hand, in the invention described in claim 6, the sensor chip having a magnetic detection element and a bias magnet for applying a bias magnetic field to the magnetic detection element are provided, and a mountain is formed along the circumferential direction in the vicinity of the sensor chip. Rotation detecting device for detecting a rotation mode of the rotor by detecting a change of a magnetic vector generated in the bias magnetic field by the magnetic detection element when a magnetic rotor in which a portion and a trough are alternately arranged periodically rotates. In this case, another magnetic body (peripheral magnetic body) is disposed in the vicinity of the rotor for an arbitrary purpose, and for the rotor, at least the surfaces of the peak portion and the valley portion have the same polarity (S Pole or N pole).

  In this way, by magnetizing the rotor that is the detection object, the bias magnetic field generated from the bias magnet is more attracted toward the rotor that is the detection object than the peripheral magnetic body, The amount of deflection of the bias magnetic field toward the peripheral magnetic material side is suppressed. In other words, even in an installation environment having a peripheral magnetic body in the vicinity of the rotor that is the detection target, the influence from the peripheral magnetic body is naturally suppressed, and the accuracy of rotation detection and thus the reliability of the detection Will be kept high.

  Moreover, the structure as described in any one of the said Claims 1-6 is the magnetism which changes resistance value according to a magnetic field by a magnetoresistive effect as said magnetic detection element as invention of Claim 7. This is particularly effective when applied to a resistive element. Since the magnetoresistive element is particularly susceptible to the influence of the surrounding magnetic material, the above configuration is particularly effective when applied in such a case.

(First embodiment)
Hereinafter, a first embodiment in which a rotation detection device according to the present invention is embodied will be described with reference to FIG. This rotation detection device is also optimized as a rotation detection device used for, for example, an engine crank angle sensor.

  FIG. 1A is a perspective view showing the arrangement of the sensor main body used in this rotation detection device, particularly with respect to the positional relationship with the rotor that is the object to be detected. The arrangement of the sensor main body is basically the same as the arrangement shown in FIG. 6. Here, the vicinity of the sensor main body and the rotor arranged opposite to each other is shown enlarged. Has been. However, the description of overlapping parts such as the power supply terminal, the output terminal, and the ground (grounding) terminal shown in FIG. 6 is partially omitted.

  As shown in FIG. 1 (a), this rotation detecting device also includes a magnetoresistive element pair M1 composed of magnetoresistive elements MRE1 and MRE2 and a magnetoresistive element pair M2 composed of magnetoresistive elements MRE3 and MRE4. A chip 1 is integrated with a signal processing circuit and molded and sealed to form a sensor chip (mold IC) 2. The sensor chip 2 is mounted in a hollow portion 4 provided for the bias magnet 3 and is disposed so as to face the magnetic rotor RT that is a detection target. Although not shown, the semiconductor chip 1 is mounted on one end of the lead frame inside the sensor chip 2 as in the apparatus shown in FIG. Each terminal such as a terminal and a ground (ground) terminal is drawn out.

  In the rotation detecting device according to this embodiment, in addition to the rotor RT, a magnetic member (peripheral magnetic body) MT made of a ferromagnetic material such as iron is disposed around the sensor chip 2. Has been. The peripheral magnetic body MT is used, for example, as a counterweight of a crankshaft, a ring gear of a flywheel, or a bolt for fixing various parts.

  Also in the rotation detection device having such a configuration, the magnetoresistive elements MRE1 and MRE2 constituting the magnetoresistive element pair M1 and the magnetoresistive elements MRE3 and MRE4 constituting the magnetoresistive element pair M2 each constitute a half bridge circuit. ing. This is also the same as the device shown in FIG. 6, but various processing such as differential amplification and binarization is performed by the signal processing circuit on the change in the midpoint potential of each half bridge circuit. After that, the electric signal is taken out through the output terminal. That is, when the rotor RT rotates, the magnetic vector changes in the bias magnetic field applied to the magnetoresistive element pair M1 and M2. At this time, the change in the magnetic vector is detected as a change in the resistance value of the magnetoresistive elements MRE1 to MRE4, and an electrical signal corresponding to the change in the magnetic vector is output from the sensor chip 2. Thereby, the rotation mode of the rotor RT is obtained from the electric signal.

  FIG. 1B is a plan view of FIG. Here, the details of the planar structure of the bias magnet 3 and the hollow portion 4 provided in the magnet are shown in particular, omitting the description of the sensor chip 2 and the like. The hollow portion 4 is also provided in the longitudinal direction of the bias magnet 3 as a through hole having a quadrangular prism (plate) shape corresponding to the sensor chip 2. And the said sensor chip 2 is accommodated in this hollow part 4, and is being fixed by the adhesive etc. in the predetermined position. Also, the arrow in FIG. 1B indicates the direction of the bias magnetic field (exactly its magnetic vector) emitted from the bias magnet 3.

  The bias magnet 3 is also composed of, for example, a magnet formed by mixing and mixing magnetic powder and resin. However, as shown in FIG. 1B, the shape of the columnar shape (shown by a broken line in the figure) as a reference shape is such that the column surface facing the peripheral magnetic body MT and the column surface on the opposite side are Both are formed flat.

  Thus, in this embodiment, the bias magnet 3 is arranged with a selectively thinned shape on the peripheral magnetic body MT side. For this reason, the shake amount of the bias magnetic field toward the peripheral magnetic body MT is suppressed. As a result, even in an installation environment having the peripheral magnetic body MT in the vicinity of the rotor RT as the detection target, the influence from the peripheral magnetic body MT is naturally suppressed, and the accuracy of rotation detection, and consequently The detection reliability is maintained high.

  Further, the bias magnet 3 has a columnar shape composed of columnar surfaces arranged symmetrically with respect to the hollow portion 4, that is, a columnar shape having an equal thickness symmetrically with respect to the hollow portion 4. As a result, a magnetic field is applied symmetrically from the periphery to the hollow portion 4 of the bias magnet 3 and thus to the sensor chip 2 attached thereto, so that the accuracy of rotation detection is maintained higher.

As described above, according to the rotation detection device according to this embodiment, the following excellent effects can be obtained.
(1) A configuration of a rotation detection device that detects a rotation mode of the magnetic rotor RT based on a change in magnetic vector by the magnetoresistive elements MRE1 to MRE4, and a bias magnet 3 that applies a bias magnetic field to the magnetoresistive elements MRE1 to MRE4 However, the thickness of the peripheral magnetic body MT disposed in the vicinity of the rotor RT is selectively thinned. As a result, even in an installation environment having the peripheral magnetic body MT in the vicinity of the rotor RT that is the detection target, the influence from the peripheral magnetic body MT is naturally suppressed, and the accuracy of rotation detection, and consequently Detection reliability is maintained high.

  (2) Since the hollow portion 4 to which the sensor chip 2 is mounted has a quadrangular prism (plate) shape corresponding to the sensor chip 2, the positioning of the sensor chip 2 is facilitated. Moreover, the hollow portion 4 having such a quadrangular prism shape can be easily formed.

  (3) The bias magnet 3 has a cylindrical shape as a reference shape and is arranged with a flattened shape of a column surface facing the peripheral magnetic body MT. Thereby, the selective thinning of the bias magnet 3 can be easily realized without changing the shape of the hollow portion 4 of the bias magnet 3.

  (4) Since the bias magnet 3 has a column shape composed of column surfaces symmetrically arranged with respect to the hollow portion 4 provided in the magnet, the accuracy of rotation detection is maintained higher. become.

  (5) A magnetoresistive element that changes the resistance value according to the magnetic field by the magnetoresistive effect is adopted as a magnetic detection element that senses a change in magnetic vector. According to the rotation detection device according to this embodiment, even when a magnetoresistive element that is particularly susceptible to the influence of the peripheral magnetic body MT is adopted among the magnetic detection elements, the accuracy of rotation detection is maintained high. .

The rotation detection device according to the first embodiment can also be implemented in the following manner.
-The shape and arrangement | positioning aspect of the said bias magnet 3 are not restricted to the aspect illustrated in FIG.1 (b). For example, instead of the cylindrical shape, a regular polygonal column shape (for example, a regular quadrangular prism shape, a regular hexagonal column shape, a regular octagonal column shape, or the like) is used as a reference shape, and the bias magnet 3 has the peripheral magnetic body MT with respect to the regular polygonal column shape. It is good also as a structure arrange | positioned with the shape formed in the flatness of the column surface which opposes.

  In addition, as shown in FIG. 2, for example, the bias magnet 3 has a quadrangular prism shape (shown by a broken line in the drawing) as a reference shape of the hollow portion 4 provided in the magnet, and the peripheral magnetic body MT. It is good also as a structure arrange | positioned with the shape which curved both the opposing column surface and the opposite column surface convexly outward. Even with such a configuration, the selective thinning of the bias magnet 3 described above can be easily realized.

  Also, for example, as shown in FIGS. 3A and 3B, the bias magnet 3 is disposed with a shape having one or more cuts (slits) on the peripheral magnetic body MT side and the opposite side. It is good also as a structure to be. That is, the apparatus illustrated in FIG. 3A is provided with slits SL11 and SL12, and the apparatus illustrated in FIG. 3B is provided with slits SL21, SL22, SL31, and SL32. Even with such a configuration, the same effect as the effect (3) or an effect equivalent thereto can be obtained.

  Furthermore, it is not an essential configuration that the bias magnet 3 has a column shape including column surfaces symmetrically arranged with respect to the hollow portion 4 provided in the magnet. That is, for example, in the configuration shown in FIG. 3A, the slit SL11 may be provided only on the peripheral magnetic body MT side as shown in FIG. 4A.

  As shown in FIG. 4B, the thickness of the bias magnet 3 on the peripheral magnetic body MT side can also be selected by biasing the position of the hollow portion 4 toward the peripheral magnetic body MT. Thinning is possible. However, in this case, the sensor chip 2 mounted in the hollow portion 4 is also disposed close to the peripheral magnetic body MT, and there is a concern that the influence received from the peripheral magnetic body MT may be somewhat increased. . For this reason, the said structure (structure illustrated in FIGS. 1-3) which can implement | achieve thickness reduction, keeping a distance with the peripheral magnetic body MT constant is more preferable.

Furthermore, the configurations illustrated in FIGS. 1 to 4 can be appropriately combined.
After all, the bias magnet 3 for applying a bias magnetic field to the magnetoresistive elements MRE1 to MRE4 is disposed with a selectively thinned shape on the peripheral magnetic body MT side disposed in the vicinity of the rotor RT. If it is the structure which is made, at least the effect of said (1) can be acquired and the intended purpose will be achieved.

(Second Embodiment)
Next, a second embodiment in which the rotation detection device according to the present invention is embodied will be described with reference to FIG. FIG. 5 is a perspective view corresponding to FIG. 1A, and the same elements as those shown in FIG. 1A are denoted by the same reference numerals. Duplicate explanations are omitted. Also in the apparatus according to this embodiment, the shape and arrangement of the bias magnet are the same as those in the apparatus according to the first embodiment or its modification (FIGS. 1 to 4).

  As shown in FIG. 5, in the apparatus according to this embodiment, as in the first embodiment, the sensor chip 2 attached to the hollow portion 4 of the bias magnet 3 is the object to be detected. It is arranged so as to face a certain magnetic rotor RT. In addition to the rotor RT, a magnetic member (peripheral magnetic body) MT made of a ferromagnetic material such as iron is disposed around the sensor chip 2 for an arbitrary purpose. However, in this embodiment, at least the surfaces of the crests and troughs of the rotor RT are magnetized to the same polarity (S pole or N pole).

  Thus, by magnetizing the rotor RT that is the detection target, the bias magnetic field generated from the bias magnet 3 is attracted more toward the rotor RT that is the detection target than the peripheral magnetic body MT. As a result, the deflection amount of the bias magnetic field toward the peripheral magnetic body MT is suppressed. That is, even in an arrangement environment having the peripheral magnetic body MT in the vicinity of the rotor RT as the detection target, the influence from the peripheral magnetic body MT is naturally suppressed, and the accuracy of rotation detection, and thus the detection thereof High reliability will be maintained.

  As described above, according to the rotation detection device according to this embodiment, in addition to the same effects as the effects (1) to (5) according to the first embodiment or effects equivalent thereto, the following Such an effect can be obtained.

  (6) At least the surfaces of the crests and troughs of the magnetic rotor RT that is the detection object are magnetized to the same polarity. As a result, the accuracy of rotation detection and thus the reliability of the detection can be maintained high.

(Other embodiments)
Each of the above embodiments may be modified as follows.
-In the said 2nd Embodiment, it is not essential to employ | adopt the shape and arrangement | positioning aspect (FIGS. 1-4) of the bias magnet which concern on 1st Embodiment and its modification, 2nd Embodiment The configuration of rotor magnetization according to this embodiment can also be employed alone. Even when this configuration is used alone, at least the effect (6) can be obtained.

  In each of the above embodiments, the magnetoresistive elements MRE1 to MRE4 that change the resistance value according to the magnetic field by the magnetoresistive effect are adopted as the magnetic detection elements. However, the present invention is not limited to this. For example, a Hall element that outputs a Hall voltage signal corresponding to the magnetic field by the Hall effect can be used instead. In short, any element that can sense a change in magnetic vector can be used as the magnetic detection element.

  In each of the above embodiments, a sensor chip that is molded and sealed is adopted. However, the present invention is not limited to this, and any configuration may be used as long as it includes a magnetic detection element. The chip can be adopted.

  The hollow portion 4 of the bias magnet 3 may be a groove instead of a through hole. Further, the shape of the hollow portion 4 can be appropriately changed according to the shape of the sensor chip 2.

In the first embodiment of the rotation detection device according to the present invention, (a) is a perspective view showing the arrangement of the sensor main body used in the rotation detection device, particularly with respect to the positional relationship with the rotor to be detected. FIG. 4B is a plan view of FIG. The top view which shows one of the modifications about the shape and arrangement | positioning aspect of a bias magnet used for the apparatus which concerns on the same 1st Embodiment. (A) And (b) is a top view which shows another modification of the shape and arrangement | positioning aspect of the same magnet. (A) And (b) is a top view which shows another modification of the shape and arrangement | positioning aspect of the same magnet. The perspective view which shows the arrangement | positioning aspect of the sensor main body used for the rotation detection apparatus centering on 2nd Embodiment of the rotation detection apparatus which concerns on this invention especially on the positional relationship with the rotor which is a to-be-detected object. The top view which shows the arrangement | positioning aspect of the sensor main body used for the apparatus about an example of the conventional rotation detection apparatus centering on the positional relationship with the rotor which is a detection target especially. (A) is a perspective view showing in detail the internal structure of a sensor main body used in the conventional apparatus, and (b) is a plan view showing details of the shape of a bias magnet. The top view which shows a magnetic vector change when a periphery magnetic body is arrange | positioned around the sensor main body.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Semiconductor chip, 2 ... Sensor chip (mold IC), 3 ... Bias magnet, 4 ... Hollow part, M1, M2 ... Magnetoresistive element pair, MRE1-MRE4 ... Magnetoresistive element, MT ... Magnetic member (peripheral magnetic body) , RT: Magnetic rotor.

Claims (7)

When a sensor chip including a magnetic detection element is mounted in a hollow portion provided for a bias magnet that applies a bias magnetic field to the magnetic detection element, and the magnetic rotor rotates in the vicinity of the sensor chip In the rotation detection device for detecting the rotation mode of the rotor by sensing the change of the magnetic vector generated in the bias magnetic field by the magnetic detection element,
Another magnetic body is disposed in the vicinity of the rotor for an arbitrary purpose, and the bias magnet is disposed with a shape in which the thickness on the magnetic body side disposed in the vicinity of the rotor is selectively thinned. A rotation detector characterized by being provided. In the selective thinning of the bias magnet, a rectangular column shape, which is a reference shape of the hollow portion provided in the bias magnet, has at least a column surface facing a magnetic body disposed in the vicinity of the rotor as a convex outer side. The rotation detection device according to claim 1, wherein the rotation detection device is realized based on curving to the right. The selective thinning of the bias magnet is based on the fact that a cylindrical surface or a regular polygonal column shape as a reference shape of the bias magnet is flattened at least on a column surface facing a magnetic body disposed in the vicinity of the rotor. The rotation detection device according to claim 1 or 2, wherein the rotation detection device is realized. The selective thinning of the bias magnet is realized based on the fact that one or a plurality of cuts are formed on the magnetic material side disposed at least near the rotor of the bias magnet. The rotation detection device according to any one of claims. The rotation detection device according to any one of claims 1 to 4, wherein the bias magnet has a column shape including column surfaces symmetrically arranged with respect to a hollow portion provided in the bias magnet. A sensor chip having a magnetic detection element and a bias magnet for applying a bias magnetic field to the magnetic detection element, and crests and troughs are alternately arranged along the circumferential direction in the vicinity of the sensor chip. In the rotation detection device for detecting a rotation mode of the rotor by detecting a change in a magnetic vector generated in the bias magnetic field when the magnetic rotor rotated is detected by the magnetic detection element,
Another magnetic body is disposed in the vicinity of the rotor for an arbitrary purpose, and the rotor is formed by magnetizing at least the surfaces of the peak and the valley to the same polarity. Detection device. The rotation detection device according to any one of claims 1 to 6, wherein the magnetic detection element is a magnetoresistive element that changes a resistance value according to a magnetic field by a magnetoresistive effect.

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