JP2021076419A - Rotation angle sensor and rotation angle detector - Google Patents

Abstract

To provide a rotation angle sensor that can suppress reduction of the detection accuracy.SOLUTION: The rotation angle sensor includes: a sensor chip 21 having a magnetic resistance element, the sensor chip facing a magnetization rotor 110; and a casing 30 equipped with the sensor chip 21. In a part of the casing 30 which is located in a side opposite to the side near the magnetization rotor 110 across the sensor chip 21, a shield member 80 made of a magnetic material is arranged.SELECTED DRAWING: Figure 1

Description

The present invention relates to a rotation angle sensor and a rotation angle detection device that detect the rotation of a magnetizing rotor.

Conventionally, a rotation angle sensor that detects the rotation of a magnetizing rotor has been proposed (see, for example, Patent Document 1). Specifically, this rotation angle sensor targets a ring-shaped magnetizing rotor that rotates with the axle of the vehicle as a rotation detection target, and is arranged so as to face the surface of the magnetizing rotor.

The magnetizing rotor is a rotor in which the north pole and the south pole are alternately magnetized along the circumferential direction. The rotation angle sensor is configured to have a sensor chip on which a magnetoresistive element whose resistance value changes based on a change in the applied magnetic vector is formed, and is configured to output a detection signal corresponding to the magnetic vector. There is.

Then, the rotation angle sensor detects the replacement of the magnetic poles (that is, S pole and N pole) accompanying the rotation of the magnetizing rotor. Specifically, in the rotation angle sensor, when the magnetizing rotor rotates, the magnetic vector that affects the magnetoresistive element changes, so the resistance value of the magnetoresistive element corresponding to this change in the magnetic vector (that is, the deflection angle). Based on the change, a detection signal corresponding to the rotation of the magnetizing rotor is output.

Japanese Unexamined Patent Publication No. 2006-3225

By the way, in the rotation angle sensor as described above, in order to detect the rotation angle of the magnetizing rotor based on the change in the resistance value of the magnetoresistive element corresponding to the deflection angle of the magnetic vector, the magnetic vector applied to the magnetoresistive element is detected. The angle is important. In this case, if a magnetic vector other than the magnetizing rotor, such as a magnetic vector of an external magnetic field, is applied to the rotation angle sensor (that is, a magnetoresistive element), the detection accuracy is lowered.

In view of the above points, it is an object of the present invention to provide a rotation angle sensor and a rotation angle detection device capable of suppressing a decrease in detection accuracy.

In claim 1 for achieving the above object, a rotation angle sensor that detects the rotation angle of a magnetizing rotor (110) that has a disk shape and is magnetized with N poles and S poles alternately along the circumferential direction. It is provided with a sensor chip (21) provided with a magnetic resistance element and arranged so as to face the magnetizing rotor, and a casing (30) on which the sensor chip is mounted, and the sensor chip is sandwiched between the casings. A shield member (80) made of a magnetic material is arranged at a portion located on the opposite side of the magnetizing rotor.

According to this, when the rotation angle sensor is used, the shield member is arranged on the side opposite to the magnetizing rotor with the sensor chip in between. Therefore, the shield member can prevent the external magnetic vector from reaching the sensor chip from the side opposite to the magnetizing rotor. Therefore, it is possible to suppress a decrease in detection accuracy.

Further, in claim 6, the rotation angle sensor (1), the magnetizing rotor (110), and the magnetizing rotor according to any one of claims 1 to 5 are provided, and the magnetizing rotor is mounted. A holding member (120) fixed to the member is provided, and the holding member is arranged on the side opposite to the rotation angle sensor with the magnetizing rotor interposed therebetween, and is made of a magnetic material.

According to this, since the holding member is made of a magnetic material, it is possible to prevent an external magnetic vector from reaching the sensor chip from the magnetizing rotor side. Therefore, it is possible to further suppress a decrease in detection accuracy.

The reference reference numerals in parentheses attached to each component or the like indicate an example of the correspondence between the component or the like and the specific component or the like described in the embodiment described later.

It is sectional drawing which shows the rotation angle detection device. It is a detailed cross-sectional view of the mold member in FIG. It is a top view which shows the positional relationship of a magnetizing rotor, a mold member, and a terminal as seen from the direction of arrow III in FIG. It is a top view which shows the positional relationship of a magnetizing rotor, a mold member, and a shield member seen from the direction of arrow IV in FIG. It is sectional drawing which shows the rotation angle detection apparatus in 2nd Embodiment. It is sectional drawing which shows the rotation angle detection apparatus in 3rd Embodiment. It is a top view which shows the positional relationship of a magnetizing rotor, a mold member, and a shield member seen from the direction of arrow VII in FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each of the following embodiments, parts that are the same or equal to each other will be described with the same reference numerals.

(First Embodiment)
The first embodiment will be described with reference to the drawings. The rotation angle detection device of the present embodiment is preferably mounted on a vehicle such as an automobile and used to detect the rotation of a magnetizing rotor provided on an axle.

As shown in FIG. 1, the rotation angle detection device includes a rotation angle sensor 10 and a rotor unit 100. First, the configuration of the rotation angle sensor 10 will be described. The rotation angle sensor 10 is configured by mounting the mold member 20 on the casing 30. Hereinafter, the upper side of the paper surface in FIG. 1 will be referred to as one end side, and the lower side of the paper surface in FIG. 1 will be referred to as the other end side.

As shown in FIG. 2, the mold member 20 includes a sensor chip 21, a circuit chip 22, a lead frame 23, a mold resin 26 for sealing these, and the like.

The sensor chip 21 is configured to output a detection signal according to the applied magnetic vector. In the present embodiment, the sensor chip 21 is formed with two magnetoresistive elements whose resistance value changes according to the magnetic vector. The magnetoresistive element is connected so as to form a bridge circuit. The two magnetoresistive elements are symmetrically formed with the center of the sensor chip 21 in between.

As the circuit chip 22, an IC chip or the like in which a drive circuit for driving the sensor chip 21 or a processing circuit for performing processing such as amplification processing on the detection signal is formed is used.

The lead frame 23 includes an island portion 23a on which the sensor chip 21 and the circuit chip 22 are mounted via an adhesive (not shown), and a terminal portion 23b that electrically connects to the outside. The lead frame 23 is made of a metal having excellent conductivity such as general copper (Cu) or 42 alloy, and is processed into a predetermined shape by etching or pressing. In the present embodiment, the island portion 23a has a rectangular shape in a plane, and the terminal portion 23b is arranged around the island portion 23a.

The sensor chip 21 and the circuit chip 22 are electrically connected to each other via the bonding wire 24. The circuit chip 22 and one end of the terminal 23b are electrically connected via a bonding wire 25. The bonding wires 24 and 25 are made of gold, aluminum, or the like.

The mold resin 26 is made of a general epoxy resin or the like, and is formed by a transfer molding method or the like using a mold. Specifically, the mold resin 26 is formed so that the other end side of the terminal portion 23b is exposed and the sensor chip 21, the circuit chip 22, the lead frame 23, and the bonding wires 24 and 25 are sealed. ..

As shown in FIG. 1, the casing 30 is configured to include a connector case 40 and a cap 70. The connector case 40 is configured to include a sub case 50 and a main case 60. The subcase 50 is made, for example, by molding a resin such as polyphenylene sulfide (ie, PPS) or polybutylene terephthalate (ie, PBT). The sub case 50 has a recess 51 formed on the outer peripheral surface on one end side.

The sub-case 50 is provided with a plurality of metal rod-shaped terminals 52 for electrically connecting the sensor chip 21 and an external circuit or the like. Each of these terminals 52 is held in the sub case 50 by being integrally molded with the sub case 50 by insert molding. Although only one terminal 52 is shown in FIG. 1, a plurality of terminals 52 are actually provided.

Specifically, each terminal 52 is held in the sub case 50 so that one end is exposed from the recess 51 in the sub case 50 and the other end protrudes from the other end side of the sub case 50. The other end of the terminal 52 protruding from the other end side of the sub case 50 is electrically connected to an external circuit or the like via an external wiring member such as a wire harness (not shown).

The mold member 20 is arranged in the recess 51 of the sub case 50. The other end of the terminal 23b of the mold member 20 exposed from the mold resin 26 and one end of the terminal 52 are electrically connected by welding or the like. As a result, the sensor chip 21 is electrically connected to the terminal 52 via the circuit chip 22 and the terminal portion 23b, and is connected to the external circuit.

Like the sub-case 50, the main case 60 is made by molding a resin such as polyphenylene sulfide or polybutylene terephthalate. The main case 60 is integrated with the sub case 50 by being integrally molded with the sub case 50 by insert molding.

Specifically, the main case 60 is formed so that one end side of the sub case 50 is exposed from one end side. Specifically, the main case 60 is formed so that the mold member 20 and the like mounted on one end side of the sub case 50 are exposed. Further, in the main case 60, a tubular insertion portion 61 is formed on one end side, and an opening 62 for exposing the other end of the terminal 52 is formed on the other end side.

Further, in the main case 60, an annular groove portion 63 is formed between one end side and the other end side. An O-ring 64 is arranged in the groove 63.

The cap 70 is made by molding a resin such as polyphenylene sulfide or polybutylene terephthalate, and has a bottomed tubular shape with an opening on the other end side. The cap 70 is integrated with the main case 60 by press-fitting the opening side into the insertion portion 61 of the main case 60 so as to accommodate the mold member 20 and the like.

Then, in the present embodiment, the shield member 80 is arranged in the sub-case 50 on the portion opposite to the side on which the sensor chip 21 is arranged. In other words, in the sub-case 50, assuming that the portion opposite to the bottom surface of the recess 51 in which the sensor chip 21 is arranged is the opposite portion 53, the shield member 80 is arranged in the opposite portion 53. The shield member 80 is made of a magnetic material such as iron, and is made of, for example, SPCC, S45C, or the like. Further, the shield member 80 is arranged via a joining member made of, for example, a silicone-based adhesive. As will be described later, the rotation angle sensor 10 is arranged so that the sensor chip 21 of the mold member 20 faces the magnetizing rotor 110. Therefore, in other words, the opposite portion 53 can be said to be a portion of the sub-case 50 opposite to the magnetizing rotor 110.

The above is the configuration of the rotation angle sensor 10 in this embodiment.

As shown in FIGS. 1, 3, and 4, the rotor portion 100 is configured to include a magnetizing rotor 110, a holding member 120, and the like. The magnetizing rotor 110 has an annular shape having one surface 110a and another surface 110b, and is magnetized alternately with north and south poles along the circumferential direction. The magnetizing rotor 110 is provided with a holding member 120 on the other surface 110b side, and the holding member 120 is fixed to an axle as a mounted member so that the magnetizing rotor 110 rotates together with the axle. The holding member 120 is arranged on almost the entire surface of the other surface 110b of the magnetizing rotor 110.

The rotation angle detection device is configured by arranging the rotation angle sensor 10 so as to face one surface 110a of the magnetizing rotor 110. In this case, the rotation angle sensor 10 is arranged so that the mold member 20 faces one surface 110a of the magnetizing rotor 110. That is, the rotation angle sensor 10 is arranged so that the shield member 80 and the magnetizing rotor 110 are located so as to sandwich the mold member 20.

The rotation angle sensor 10 is preferably arranged so that the center of the sensor chip 21 in the mold member 20 and the center between the inner diameter and the outer diameter of the magnetizing rotor 110 face each other. As a result, in the present embodiment, since the sensor chip 21 is symmetrically formed with two magnetoresistive elements with the center of the sensor chip in between, a magnetic vector caused by the magnetizing rotor 110 is formed on the sensor chip 21. It becomes easy to apply evenly to the two magnetoresistive elements, and the detection sensitivity can be improved.

As described above, in the present embodiment, the shield member 80 is arranged on the side opposite to the magnetizing rotor 110 with the sensor chip 21 interposed therebetween. Therefore, the shield member 80 can prevent the external magnetic vector from reaching the sensor chip 21 from the side opposite to the magnetizing rotor 110. Therefore, it is possible to suppress a decrease in detection accuracy.

(Second Embodiment)
The second embodiment will be described. In this embodiment, the shield member 80 is arranged on the cap 70 as compared with the first embodiment. Others are the same as those in the first embodiment, and thus the description thereof will be omitted here.

In this embodiment, as shown in FIG. 5, the shield member 80 is arranged on the outer peripheral surface of the cap 70. Specifically, in the shield member 80, the shield member 80 is arranged on a portion of the outer peripheral surface of the cap 70 that faces the opposite portion 53 of the sub case 50.

Even if the shield member 80 is arranged on the cap 70 in this way, the same effect as that of the first embodiment can be obtained.

(Third Embodiment)
The third embodiment will be described. In this embodiment, the shape of the shield member 80 is changed from that of the first embodiment. Others are the same as those in the first embodiment, and thus the description thereof will be omitted here.

In the present embodiment, as shown in FIGS. 6 and 7, the shield member 80 is configured to have a side portion 81 projecting toward the mold member 20 (that is, the sensor chip 21). Specifically, in the arrangement direction of the shield member 80 and the mold member 20 (that is, the sensor chip 21), the side portion 81 is formed so as to intersect the rotation direction of the magnetizing rotor 110 and is magnetized. It is formed so as to intersect the radial direction of the rotor 110. That is, the side portion 81 is formed so as to substantially surround the mold member 20. However, in the present embodiment, the side portion 81 is formed so as not to reach the bottom surface of the recess 51.

In other words, the arrangement direction of the shield member 80 and the mold member 20 can be said to be when viewed from the arrangement direction of the shield member 80 and the mold member 20. In other words, the arrangement direction of the shield member 80 and the mold member 20 can be said to be when viewed from the arrangement direction of the mold member 20 and the magnetizing rotor 110, and is viewed from the other surface 110b side of the magnetizing rotor 110. It can also be said that it was a time.

According to this, since the side portion 81 is formed, it is possible to prevent the external magnetic vector from reaching the sensor chip 21 even by the side portion 81. Therefore, it is possible to further suppress a decrease in detection accuracy.

Further, in the present embodiment, the side portion 81 is formed so as not to reach the bottom surface of the recess 51. Therefore, it is possible to suppress the magnetic vector from the magnetizing rotor 110 from being absorbed by the side portion 81, and it is possible to suppress a decrease in sensitivity.

(Other embodiments)
The present invention is not limited to the above-described embodiment, and can be appropriately modified within the scope of the claims.

For example, in each of the above embodiments, the holding member 120 may be made of the same magnetic material as the shield member 80. According to this, the holding member 120 can prevent the external magnetic vector from reaching the sensor chip 21 from the magnetizing rotor 110 side by the holding member 120. Therefore, it is possible to further suppress a decrease in detection accuracy.

Further, in the third embodiment, the side portion 81 is a portion formed so as to intersect the circumferential direction of the magnetizing rotor 110 and a portion formed so as to intersect the radial direction of the magnetizing rotor 110. Only one of them may be formed. Further, the side portion 81 may be formed so as to extend beyond the bottom surface of the recess 51.

10 Rotation angle sensor 21 Sensor chip 30 Casing 80 Shield member 110 Magnetizing rotor

Claims (6)

A rotation angle sensor that has an annular shape and detects the rotation angle of a magnetizing rotor (110) in which N poles and S poles are alternately magnetized along the circumferential direction.
A sensor chip (21) provided with a magnetoresistive element and arranged so as to face the magnetizing rotor.
A casing (30) on which the sensor chip is mounted is provided.
A rotation angle sensor in which a shield member (80) made of a magnetic material is arranged in a portion of the casing located on the side opposite to the magnetizing rotor with the sensor chip interposed therebetween. The casing has a connector case (40) in which the sensor chip is arranged.
The rotation angle sensor according to claim 1, wherein the shield member is provided in a portion of the connector case located on the side opposite to the portion where the sensor chip is arranged. Claim 1 or 2 has the shield member having a side portion (81) protruding toward the sensor chip so as to intersect the rotation direction of the magnetizing rotor in the arrangement direction of the shield member and the sensor chip. The rotation angle sensor described in. Claims 1 to 3 have the shield member having a side portion (81) protruding toward the sensor chip so as to intersect the radial direction of the magnetizing rotor in the arrangement direction of the shield member and the sensor chip. The rotation angle sensor according to any one of. The casing has a connector case (40) on which the sensor chip is arranged and a cap (70) integrated with the connector case so as to accommodate the sensor chip.
The rotation angle sensor according to claim 1, wherein the shield member is provided on an outer peripheral surface of the cap. The rotation angle sensor (1) according to any one of claims 1 to 5 and the rotation angle sensor (1).
With the magnetizing rotor (110)
The magnetizing rotor is provided with a holding member (120) for fixing the magnetizing rotor to the mounted member.
A rotation angle detection device in which the holding member is arranged on the side opposite to the rotation angle sensor with the magnetizing rotor interposed therebetween and is made of a magnetic material.

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