Magnetic sensor device and rotation detection device

Abstract

To suppress misalignment between multiple magnetic sensors and reduce the labor required for mounting work when mounting the multiple magnetic sensors on a substrate in order to detect the rotation of a rotating body using the multiple magnetic sensors.SOLUTION: A magnetic sensor device 3 comprises: multiple magnetic sensors 4 which include a magnetic wire material 5 exhibiting large Barkhausen effect and a coil arranged on the outer circumference of the magnetic wire material 5; and a casing 16 to which the multiple magnetic sensors 4 are fixed. The multiple magnetic sensors 4 are arranged on the same reference surface as the lower surface of the casing 16 at a prescribed interval in the circumferential direction around a reference line that is perpendicular to the reference surface such that the extension direction of the magnetic wire material 5 is parallel to the reference surface.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a magnetic sensor device that utilizes the large Barkhausen effect, and a rotation detection device that includes the magnetic sensor device. [Background technology]

[0002] A magnetic sensor using the Large Barkhausen effect includes a magnetic wire that exhibits the Large Barkhausen effect, and a coil provided on the outer periphery of the magnetic wire. Specifically, the magnetic sensor includes a bobbin for determining the positions of the magnetic wire and the coil, the magnetic wire is disposed inside the shaft of the bobbin, and the coil is formed by winding an electric wire around the outer periphery of the shaft of the bobbin. An example of such a magnetic sensor is described in International Publication No. 2016 / 021074 (Patent Document 1).

[0003] For example, as described in International Publication No. 2016 / 021074, when a magnetic sensor is used to detect the rotation of a rotating body such as a rotating shaft, a magnet is fixed to the outer periphery of the rotating body so that a rotating magnetic field is formed on the outer periphery of the rotating body when the rotating body rotates. In addition, a substrate is provided on the outer periphery of the rotating body so as not to come into contact with either the rotating body or the magnet, and multiple magnetic sensors are provided on the substrate. In addition, the multiple magnetic sensors are disposed near the rotation orbit of the magnet and at different positions in the rotation direction of the magnet. This allows the multiple magnetic sensors to detect the rotating magnetic field formed by the rotation of the rotating body, and the amount of rotation and the direction of rotation of the rotating body can be detected based on the detection signal output from the coil of each magnetic sensor. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2016 / 021074 Summary of the Invention [Problem to be solved by the invention]

[0005] In order to improve the detection accuracy when detecting the rotation of a rotating body using multiple magnetic sensors, it is necessary to improve the accuracy of the arrangement of the multiple magnetic sensors on the board. However, in the conventional technology, since the multiple magnetic sensors are individually mounted on the board, the arrangement of the multiple magnetic sensors on the board may be misaligned. In addition, the task of individually mounting the multiple magnetic sensors on the board is time-consuming.

[0006] The present invention has been made in consideration of problems such as those described above, and an object of the present invention is to provide a magnetic sensor device and a rotation detection device that can suppress misalignment between multiple magnetic sensors when mounting multiple magnetic sensors on a substrate to detect the rotation of a rotating body using the multiple magnetic sensors, and that can reduce the effort required for mounting work. [Means for solving the problem]

[0007] In order to solve the above problems, the magnetic sensor device of the present invention comprises a magnetic wire that exhibits a large Barkhausen effect, a plurality of magnetic sensors having a coil arranged on the outer periphery of the magnetic wire, and a casing to which the plurality of magnetic sensors are each fixed, and is characterized in that the plurality of magnetic sensors are arranged on a reference plane that is the same as or parallel to the underside of the casing, at a predetermined interval in the circumferential direction around a reference line perpendicular to the reference plane, and such that the extension direction of the magnetic wire is parallel to the reference plane.

[0008] When detecting the rotation of a rotating body using a plurality of magnetic sensors, for example, a magnet is fixed to the outer periphery of the rotating body so that a rotating magnetic field is formed on the outer periphery of the rotating body when the rotating body rotates. In addition, a substrate is provided on the outer periphery of the rotating body so as not to come into contact with either the rotating body or the magnet. The substrate is arranged so that a plane including the mounting surface thereof is perpendicular to the rotation axis of the rotating body. Then, the magnetic sensor device of the present invention is provided on the mounting surface of the substrate. When providing the magnetic sensor device of the present invention on the mounting surface of the substrate, for example, the lower surface of the casing is placed on the mounting surface of the substrate. Also, the arrangement of the casing on the mounting surface of the substrate is determined so that the reference line coincides with the rotation axis of the rotating body. Since the plurality of magnetic sensors are fixed to the casing, the arrangement between the plurality of magnetic sensors on the mounting surface of the substrate is determined by placing the casing on the mounting surface of the substrate. Then, the casing or each magnetic sensor is fixed to the substrate.

[0009] In the magnetic sensor device of the present invention, the magnetic sensors are arranged on a reference plane that is the same as or parallel to the lower surface of the casing, at a predetermined interval in the circumferential direction around a reference line perpendicular to the reference plane, and the extension direction of the magnetic wire is parallel to the reference plane. Therefore, by placing the lower surface of the casing on the mounting surface of the board and determining the arrangement of the casing on the mounting surface of the board so that the reference line coincides with the rotation axis of the rotating body, the magnetic sensors can be arranged on a surface that is the same as or parallel to the mounting surface of the board, and the magnetic sensors can be arranged on the outer periphery of the rotation orbit of the magnet at a predetermined interval in the rotation direction of the magnet, and the magnetic sensors can be arranged so that the extension direction of the magnetic wire is parallel to the mounting surface of the board. In other words, by simply arranging the casing on the mounting surface of the board as described above, the arrangement of the magnetic sensors on the board that can detect the rotation of the rotating body can be determined. Therefore, according to the magnetic sensor device of the present invention, when multiple magnetic sensors are mounted on a substrate to detect the rotation of a rotating body using multiple magnetic sensors, it is possible to suppress misalignment between the multiple magnetic sensors and also reduce the effort required for mounting, compared to conventional technology in which the multiple magnetic sensors are each mounted individually on the substrate.

[0010] In addition, the magnetic sensor device of the present invention may further include a plurality of yokes for controlling the direction of the magnetic flux of an external magnetic field, the plurality of yokes being provided in one-to-one correspondence with the plurality of magnetic sensors, and the plurality of yokes being fixed to the casing together with the plurality of magnetic sensors. In this case, the plurality of yokes may be integrated with the casing by insert molding.

[0011] In order to solve the above problem, the rotation detection device of the present invention is a rotation detection device that detects the rotation of a rotating body, comprising the magnetic sensor device of the present invention, a magnetic field forming member that rotates with the rotating body and forms a rotating magnetic field on the outer periphery of the rotating body when the rotating body rotates, and a substrate having a mounting surface, the mounting surface facing upward, a plane including the mounting surface being perpendicular to the rotation axis, and arranged so as not to contact either the rotating body or the magnetic field forming member, in the vicinity of the magnetic field forming member, the casing of the magnetic sensor device is fixed to the substrate in a state in which the reference line coincides with the rotation axis of the rotating body and the lower surface of the casing is arranged on or above the mounting surface so that the reference line coincides with the rotation axis of the rotating body and the lower surface of the casing is parallel to the mounting surface of the substrate. In this rotation detection device, the casing of the magnetic sensor device is fixed to the substrate in a state in which the reference line coincides with the rotation axis of the rotating body and the lower surface of the casing is arranged on or above the mounting surface of the substrate so that the reference line coincides with the rotation axis of the rotating body and the lower surface of the casing is parallel to the mounting surface of the substrate. Specifically, the casing is fixed to the board in a state in which it is placed on the mounting surface of the board so that the reference line coincides with the rotation axis of the rotating body and the bottom surface of the casing is in contact with the mounting surface of the board, or is fixed to the board in a state in which it is positioned above the mounting surface of the board so that the reference line coincides with the rotation axis of the rotating body and the bottom surface of the casing is parallel to the mounting surface of the board. Effect of the Invention

[0012] According to the present invention, when multiple magnetic sensors are mounted on a substrate to detect the rotation of a rotating body using the multiple magnetic sensors, it is possible to suppress misalignment between the multiple magnetic sensors and also to reduce the effort required for mounting. [Brief description of the drawings]

[0013] [Figure 1] 1 is an explanatory diagram showing a state in which a rotation detection device including a magnetic sensor device according to an embodiment of the present invention is viewed from above; [Diagram 2] 2 is a cross-sectional view showing a state in which a cross section of the rotation detector taken along line II-II in FIG. 1 is viewed from the side. [Diagram 3] 1 is a perspective view showing a magnetic sensor device and a substrate according to an embodiment of the present invention. [Figure 4] FIG. 2 is an explanatory diagram showing a state in which the magnetic sensor device according to the embodiment of the present invention is viewed from below. [Diagram 5] 1A is a perspective view showing a magnetic sensor in a magnetic sensor device according to an embodiment of the present invention, as viewed from the upper right front side, and FIG. 1B is a perspective view showing the magnetic sensor as viewed from the upper right rear side. [Figure 6] 2 is a perspective view showing a bobbin in a magnetic sensor of the magnetic sensor device according to the embodiment of the present invention, as viewed from the upper right front side. FIG. [Figure 7] 2 is a perspective view showing a magnetic sensor and a yoke in the magnetic sensor device according to the embodiment of the present invention, as viewed from the upper right front side. FIG. [Figure 8] 5A to 5C are explanatory diagrams showing a method of attaching a magnetic sensor to a casing in the magnetic sensor device according to the embodiment of the present invention. [Figure 9] 3 is an explanatory diagram showing an arrangement of a magnetic sensor and a yoke within a casing of the magnetic sensor device according to the embodiment of the present invention. FIG. [Figure 10] 3 is an explanatory diagram showing an arrangement of a magnetic sensor and a yoke within a casing of the magnetic sensor device according to the embodiment of the present invention. FIG. [Figure 11] 5A to 5C are explanatory diagrams showing a magnetic field detection operation of a magnetic sensor or the like in the magnetic sensor device according to the embodiment of the present invention. [Figure 12] FIG. 4 is an explanatory diagram showing a first modified example of the magnetic sensor device according to the embodiment of the present invention. [Figure 13] FIG. 11 is an explanatory diagram showing a second modified example of the magnetic sensor device according to the embodiment of the present invention. [Figure 14] FIG. 11 is an explanatory diagram showing a third modified example of the magnetic sensor device according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] (Rotation detection device) Fig. 1 shows a rotation detection device 1 including a magnetic sensor device 3 according to an embodiment of the present invention as viewed from above. Fig. 2 shows a cross section of the rotation detection device 1 taken along line II-II in Fig. 1 as viewed from the side (from below in Fig. 1).

[0015] 1, the rotation detection device 1 is a device that detects the rotation of a rotating shaft 40 as a rotating body. The rotation detection device 1 includes a magnetic field forming member 2 that forms a rotating magnetic field, a magnetic sensor device 3 that detects the rotating magnetic field, and a substrate 31.

[0016] The magnetic field forming member 2 is formed in a ring shape from a magnetic material such as ferrite. The magnetic field forming member 2 is disposed coaxially with the rotating shaft 40 on the outer periphery of the rotating shaft 40 and is fixed to the rotating shaft 40. The magnetic field forming member 2 is a magnetized with multiple poles, and on the outer periphery of the magnetic field forming member 2, four magnetic poles, N pole, S pole, N pole, S pole, are formed in that order at intervals of 90 degrees, for example, in the circumferential direction of the magnetic field forming member 2. The magnetic field forming member 2 can also be formed from four magnets that are not magnetized with multiple poles.

[0017] The substrate 31 is provided on the outer periphery of the rotating shaft 40. The substrate 31 is provided in the vicinity of the magnetic field forming member 2. The substrate 31 is arranged so that its mounting surface 31A faces upward. As shown in FIG. 2, the substrate 31 is arranged so that a plane including the mounting surface 31A is perpendicular to the rotation axis X of the rotating shaft 40. A through hole 31B is formed in the center of the substrate 31, and the rotating shaft 40 is inserted into the through hole 31B. The center of the through hole 31B coincides with the center of rotation of the rotating shaft 40. The diameter of the through hole 31B is larger than the outer diameter of the rotating shaft 40, and the rotating shaft 40 is not in contact with the substrate 31. The substrate 31 is fixed via a bracket or the like to a housing of a device (e.g., a motor) in which the rotating shaft 40 is rotatably supported.

[0018] As described later, the magnetic sensor device 3 is formed by housing and fixing three magnetic sensors 4 and three yokes 15 in one casing 16. In FIG. 1, the three magnetic sensors 4 and three yokes 15 housed in the casing 16 are indicated by dashed lines. The magnetic sensor device 3 is disposed on the mounting surface 31A of the substrate 31 by placing the lower surface of the casing 16 on the mounting surface 31A of the substrate 31 while aligning the reference line Q of the casing 16 with the rotation axis X of the rotating shaft 40. The magnetic sensor device 3 is fixed to the substrate 31 by soldering the fixing metal fittings 22 provided on the casing 16 to the fixing pads 32 provided on the mounting surface 31A of the substrate 31.

[0019] In a state where the magnetic sensor device 3 is arranged on the mounting surface 31A of the substrate 31 in this manner, three magnetic sensors 4 are arranged on the mounting surface 31A of the substrate 31. The three magnetic sensors 4 are arranged on the outer periphery of the magnetic field forming member 2 at intervals of 120 degrees in the rotation direction of the magnetic field forming member 2. The magnetic sensors 4 are arranged such that the extension direction of the magnetic wire 5 is parallel to the mounting surface 31A of the substrate 31. When the mounting surface 31A of the substrate 31 is viewed from above, the magnetic sensors 4 are arranged such that the center of the extension direction of the magnetic wire 5 (strictly speaking, the center of the extension direction of the central axis of the magnetic wire 5) is in contact with a circle D drawn on the outer periphery of the magnetic field forming member 2 and centered on the center of rotation of the rotating shaft 40.

[0020] Moreover, in a state where the magnetic sensor device 3 is disposed on the mounting surface 31A of the substrate 31 as described above, the three yokes 15 are disposed on the mounting surface 31A of the substrate. The three yokes 15 are disposed so as to correspond one-to-one with the three magnetic sensors 4. The three yokes 15 are disposed on the outer periphery side of the magnetic field forming member 2 at intervals of 120 degrees in the rotation direction of the magnetic field forming member 2. Each yoke 15 is disposed on the inner periphery side of the magnetic sensor 4 so as to be adjacent to the magnetic sensor 4.

[0021] The magnetic field forming member 2 is not in contact with any of the three magnetic sensors or the three yokes. The magnetic field forming member 2 rotates together with the rotating shaft 40, whereas the magnetic sensor device 3 is stationary. When the magnetic field forming member 2 rotates together with the rotating shaft 40, the magnetic field formed by the magnetic field forming member 2 rotates. This forms a rotating magnetic field that rotates around the rotation axis X of the rotating shaft 40. The three magnetic sensors 4 detect this rotating magnetic field. Specifically, the direction of the magnetic field acting on each magnetic sensor 4 changes as the magnetic field formed by the magnetic field forming member 2 rotates. Each magnetic sensor 4 outputs a pulse signal corresponding to the change in the direction of the magnetic field. The amount and direction of rotation of the rotating shaft 40 can be detected based on the pulse signal output from each magnetic sensor 4.

[0022] (Magnetic sensor device) Fig. 3 shows the magnetic sensor device 3 before it is mounted on the substrate 31, and the substrate 31 as viewed diagonally from above. Fig. 4 shows the magnetic sensor device 3 as viewed from below.

[0023] The magnetic sensor device 3 includes three magnetic sensors 4, three yokes 15, and one casing 16. The magnetic sensor device 3 is a device in which the three magnetic sensors 4 and the three yokes 15 are integrated via the casing 16. As shown in FIG. 3, the three magnetic sensors 4 and the three yokes 15 are accommodated and fixed in the casing 16. Specifically, as shown in FIG. 4, the three magnetic sensors 4 are attached in three sensor accommodation holes 19 provided on the lower surface of the casing 16. The three yokes 15 are embedded in the casing 16. The three magnetic sensors 4 and the three yokes 15 are arranged at predetermined positions in the casing 16. The three magnetic sensors 4 are each identical. The three yokes 15 are each identical.

[0024] (Magnetic sensor and yoke) The following describes the magnetic sensor 4 and the yoke 15. For ease of explanation, the front (Fd), rear (Bd), top (Ud), bottom (Dd), left (Ld), and right (Rd) directions of the magnetic sensor 4 and the yoke 15 are defined as shown by the arrows drawn at the bottom right of FIGS.

[0025] Fig. 5(A) shows one of the three magnetic sensors 4 as viewed from the front upper right. Fig. 5(B) shows the magnetic sensor 4 as viewed from the rear upper right. Fig. 6 shows the bobbin 6 of the magnetic sensor 4 as viewed from the front upper right.

[0026] The magnetic sensor 4 is a part that detects the rotating magnetic field in the magnetic sensor device 3. The magnetic sensor 4 includes a magnetic wire 5, a bobbin 6, a coil 12, and two terminals 14, as shown in Fig. 5(A).

[0027] The magnetic wire 5 is a magnetic wire that exhibits the large Barkhausen effect, and is called a composite magnetic wire. The magnetic wire 5 is formed, for example, from a semi-hard magnetic material containing iron and cobalt, and is a wire having a diameter of, for example, about 0.1 mm to 1 mm and a length of, for example, about 10 mm to 30 mm. The magnetic wire 5 is formed, for example, by drawing the semi-hard magnetic material and twisting it several times while changing the direction. The magnetic wire 5 has uniaxial anisotropy, in which the direction in which magnetization is easily performed is the direction of the central axis of the magnetic wire 5. In addition, the magnetic wire 5 has a larger coercive force in the central part than in the outer peripheral part. The magnetic wire 5 has a property that the magnetization direction of the magnetic wire 5 (its outer peripheral part) suddenly reverses in response to a change in the direction of the external magnetic field.

[0028] The bobbin 6 is made of a non-magnetic material such as resin. The bobbin 6 has a symmetrical shape. As shown in FIG. 6, the bobbin 6 includes an electric wire winding section 7, two wire support sections 8, two flange sections 9, and a wire accommodating groove 10. The electric wire winding section 7 is provided in the middle of the bobbin 6 in the left-right direction and is formed in a cylindrical shape extending in the left-right direction. The wire support sections 8 are provided at the left and right ends of the bobbin 6. The flange sections 9 are provided between the electric wire winding section 7 and the left wire support section 8, and between the electric wire winding section 7 and the right wire support section 8. Each flange section 9 has a larger diameter than the electric wire winding section 7. The wire accommodating groove 10 is a groove extending from the left end to the right end of the bobbin 6.

[0029] The magnetic wire 5 is arranged inside the bobbin 6 so as to extend linearly in the left-right direction. Specifically, the magnetic wire 5 is arranged in a wire accommodating groove 10. The left end of the magnetic wire 5 is supported (fixed) to the left end of the wire accommodating groove 10 formed in the left wire support part 8 by a means such as adhesion using an adhesive. Similarly, the right end of the magnetic wire 5 is supported (fixed) to the right end of the wire accommodating groove 10 formed in the right wire support part 8. Note that instead of the wire accommodating groove 10, a wire accommodating hole that is a hole extending from the left end to the right end of the bobbin 6 may be provided, and the magnetic wire 5 may be arranged in the wire accommodating hole.

[0030] The coil 12 is provided on the outer periphery of the magnetic wire 5 arranged in the wire accommodating groove 10. Specifically, the coil 12 is formed by winding an insulated electric wire 13, such as an enameled wire, around the electric wire winding portion 7, as shown in Fig. 5(A).

[0031] As shown in FIG. 5(B), the two terminals 14 are provided at the rear of the two wire support parts 8. Specifically, one terminal 14 is provided at the terminal fixing part 11 protruding rearward from the rear surface of the left wire support part 8. The other terminal 14 is provided at the terminal fixing part 11 protruding rearward from the rear surface of the right wire support part 8. Each terminal 14 is formed in an L-shaped bent rod shape using a conductive material, for example, a metal material such as a copper alloy. One end side portion of each terminal 14 is an electric wire connection part 14A, and the other end side portion of each terminal 14 is a board connection part 14B. In each terminal 14, the electric wire connection part 14A protrudes upward from the terminal fixing part 11, and the board connection part 14B protrudes rearward from the lower side of the terminal fixing part 11. One end of the insulated electric wire 13 is fixed to the electric wire connection part 14A of one terminal 14 and is electrically connected thereto. The other end of the insulated wire 13 is fixed to and electrically connected to the wire connection portion 14A of the other terminal 14.

[0032] FIG. 7 shows the magnetic sensor 4 and the yoke 15 corresponding to the magnetic sensor 4 as viewed from the upper right front. The yoke 15 has a function of controlling the direction of the magnetic flux of an external magnetic field. Specifically, the yoke 15 controls the direction of the magnetic flux of the magnetic field formed by the magnetic field forming member 2. As shown in FIG. 7, the yoke 15 has two yoke pieces 15A. Each yoke piece 15A is formed of a soft magnetic material such as iron. A part of one yoke piece 15A is disposed in front of the left part of the magnetic sensor 4, and another part of the one yoke piece 15A is disposed above the left end part of the magnetic sensor 4. In addition, a part of the other yoke piece 15A is disposed in front of the right part of the magnetic sensor 4, and another part of the other yoke piece 15A is disposed above the right end part of the magnetic sensor 4.

[0033] (Casing) The casing 16 is formed of a non-magnetic material such as resin. As shown in Fig. 3, the casing 16 has a structure in which three sensor holding parts 17 are connected via connecting parts 18. As shown in Fig. 4, one magnetic sensor 4 and one yoke 15 are housed and fixed in each sensor holding part 17. The three sensor holding parts 17 have the same shape.

[0034] 8 shows one sensor holding portion 17 in casing 16 as viewed obliquely from below. For ease of explanation, the front (Fd), rear (Bd), top (Ud), bottom (Dd), left (Ld), and right (Rd) directions of sensor holding portion 17 are defined as shown by the arrows drawn in the lower right of FIG.

[0035] As shown in Fig. 8, the sensor holding portion 17 is formed with a sensor accommodating hole 19 for accommodating the magnetic sensor 4. The sensor accommodating hole 19 is formed on the lower surface of the sensor holding portion 17, opens downward, and is closed at the top. The opening shape of the sensor accommodating hole 19 is a rectangle according to the outer shape and size of the magnetic sensor 4 so that the magnetic sensor 4 can be inserted snugly into the sensor accommodating hole 19. The left-right dimension of the sensor accommodating hole 19 is approximately equal to the left-right dimension of the magnetic sensor 4, and the front-rear dimension of the sensor accommodating hole 19 is approximately equal to the front-rear dimension of each wire support portion 8 of the bobbin 6 of the magnetic sensor 4.

[0036] Further, notches 20 are formed in the left and right rear parts of the sensor holding part 17. When the magnetic sensor 4 is inserted into the sensor accommodating hole 19, the terminal fixing part 11 and the terminal 14 provided at the rear part of the left wire support part 8 of the bobbin 6 of the magnetic sensor 4 are disposed inside the left notch 20, and the terminal fixing part 11 and the terminal 14 provided at the rear part of the right wire support part 8 of the bobbin 6 of the magnetic sensor 4 are disposed inside the right notch 20.

[0037] In addition, a plurality of protrusions 21 protruding forward are formed on the rear surface of the sensor accommodating hole 19. When the magnetic sensor 4 is inserted into the sensor accommodating hole 19, each protrusion 21 hits the bobbin 6 hard. This fixes the magnetic sensor 4 in the sensor accommodating hole 19. When attaching the magnetic sensor 4 to the sensor holding portion 17, the worker presses the magnetic sensor 4 into the sensor accommodating hole 19. In addition, when the magnetic sensor 4 is inserted all the way into the sensor accommodating hole 19 and attached to the sensor holding portion 17, the lower surface of the bobbin 6 of the magnetic sensor 4 (the lower surface of each wire support portion 8) is disposed in the same plane as the lower surface of the sensor holding portion 17, i.e., the lower surface of the casing 16.

[0038] Further, a fixing bracket 22 for fixing the casing 16 to the substrate 31 is attached and fixed to the lower rear portion of the sensor holding portion 17.

[0039] As shown in FIG. 3, the three sensor holding parts 17 are integrated by connecting their front parts with the connecting part 18. The three sensor holding parts 17 are arranged so that their lower surfaces are located in the same plane. When the casing 16 is viewed from above, the three sensor holding parts 17 are arranged around the reference line Q at intervals of 120 degrees with the reference line Q as the center. The three sensor holding parts 17 are arranged so that their respective front parts face the reference line Q. The three sensor holding parts 17 are arranged so that the distances between the sensor holding parts 17 and the reference line Q are equal to each other. The connecting part 18 is formed in a cylindrical shape, and the center of the connecting part 18 is located on the reference line Q. The inner diameter of the connecting part 18 is set to a value larger than the outer diameter of the magnetic field forming member 2. In this embodiment, the diameter of the through hole 31B of the substrate 31 is set to a value larger than the outer diameter of the magnetic field forming member 2, and the inner diameter of the connecting portion 18 is set to a value equal to the diameter of the through hole 31B (see FIGS. 1 and 2). When viewed from above, the casing 16 has a shape that is rotationally symmetric (three-fold symmetric) about the reference line Q.

[0040] The three magnetic sensors 4 are mounted in sensor accommodating holes 19 of three sensor holding portions 17 of the casing 16. In this embodiment, the three yokes are integrated with the casing 16 by insert molding. The three yokes 15 are embedded in the three sensor holding portions 17, respectively. In each sensor holding portion 17, the yoke 15 is located in front of the sensor accommodating hole 19.

[0041] (Arrangement of magnetic sensors, etc. inside the casing) Fig. 9 shows the arrangement of the three magnetic sensors 4 and three yokes 15 inside the casing 16 as viewed from above. Fig. 10 shows the arrangement of the three magnetic sensors 4 and three yokes 15 inside the casing 16 as viewed diagonally from above. In Figs. 9 and 10, S indicates a reference plane located in the same plane as the bottom surface of the casing 16. For convenience of illustration, a lattice pattern is applied to the reference plane S.

[0042] As shown in FIGS. 9 and 10, in the casing 16, the three magnetic sensors 4 are arranged on a reference plane S located in the same plane as the lower surface of the casing 16. Specifically, the lower surface of each wire support portion 8 of the bobbin 6 of each magnetic sensor 4 is placed on the reference plane S. In addition, in the casing 16, the three magnetic sensors 4 are arranged at intervals of 120 degrees around a reference line Q perpendicular to the reference plane S. In addition, in the casing 16, the three magnetic sensors 4 are arranged so that the extension direction of the magnetic wire 5 is parallel to the reference plane S. In addition, in the present embodiment, in the casing 16, the three magnetic sensors 4 are arranged so that the center portion in the extension direction of the magnetic wire 5 (strictly speaking, the center portion in the extension direction of the central axis of the magnetic wire 5) is tangent to a reference circle C when the casing 16 is viewed from above. The reference circle C is a circle drawn on the reference plane S and its center is located on the reference line Q. The three magnetic sensors 4 are arranged such that their front portions face toward the reference line Q and the distances between the magnetic sensors 4 and the reference line Q are equal to each other. When the three magnetic sensors 4 are mounted in the three sensor accommodating holes 19 of the casing 16, the three magnetic sensors 4 are arranged in this manner.

[0043] Furthermore, within the casing 16, the three yokes are arranged on the inner circumferential side of the three magnetic sensors 4 arranged around the reference line Q so as to be adjacent to each of the three magnetic sensors 4. Specifically, the three yokes 15 are arranged on the reference plane S at intervals of 120 degrees so that their front parts face toward the reference line Q and the distances between the yokes 15 and the reference line Q are equal to each other. The three yokes 15 are embedded within the casing 16 so as to be arranged in this manner.

[0044] (Mounting of magnetic sensor device to substrate) The magnetic sensor device 3 includes three magnetic sensors 4, three yokes 15, and one casing 16, and the three magnetic sensors 4 and the three yokes 15 are integrated via the casing 16. Therefore, mounting of the magnetic sensor device 3 on the substrate 31 is substantially completed by simply mounting the casing 16, in which the three magnetic sensors 4 and the three yokes 15 are integrated, on the mounting surface 31A of the substrate 31.

[0045] When mounting the casing 16 on the mounting surface 31A of the substrate 31, the worker first places the lower surface of the casing 16 on the mounting surface 31A of the substrate 31 while aligning the reference line Q of the casing 16 with the rotation axis X of the rotating shaft 40. When the lower surface of the casing 16 contacts the mounting surface 31A of the substrate 31, the lower surfaces of the wire support parts 8 of the bobbins 6 of the magnetic sensors 4 also contact the mounting surface 31A of the substrate 31 at the same time. At the same time, the lower surfaces of the fixing metal fittings 22 provided on the casing 16 contact the fixing pads 32 provided on the mounting surface 31A of the substrate 31, and the lower surfaces of the board connection parts 14B of the terminals 14 of the magnetic sensors 4 contact the connection pads 33 provided on the mounting surface 31A of the substrate 31. Next, the fixing metal fittings 22 are soldered to the fixing pads 32. Furthermore, the board connection portion 14 B of each terminal 14 in each magnetic sensor 4 is soldered to the connection pad 33 .

[0046] 1 and 2, by mounting the casing 16 on the mounting surface 31A of the substrate 31 in this manner, the magnetic field forming member 2 is disposed inside the connecting portion 18 of the casing 16 without contacting the connecting portion 18. The position of the reference plane S shown in FIG. 9 becomes the same as the position of the mounting surface 31A, and the three magnetic sensors 4 and the three yokes 15 are disposed on the outer periphery of the magnetic field forming member 2 on the mounting surface 31A of the substrate 31 while maintaining their positional relationship formed on the reference plane S.

[0047] That is, as shown in FIGS. 1 and 2, three magnetic sensors 4 are arranged on the mounting surface 31A of the substrate 31. The three magnetic sensors 4 are arranged on the outer periphery of the magnetic field forming member 2 at intervals of 120 degrees in the rotation direction of the magnetic field forming member 2. In addition, each magnetic sensor 4 is arranged so that the extension direction of the magnetic wire 5 is parallel to the mounting surface 31A of the substrate 31. In addition, when the mounting surface 31A of the substrate 31 is viewed from above, each magnetic sensor 4 is arranged so that the center part in the extension direction of the magnetic wire 5 (strictly speaking, the center part in the extension direction of the central axis of the magnetic wire 5) is in contact with a circle D drawn on the outer periphery of the magnetic field forming member 2 and centered on the center of rotation of the rotating shaft 40. When the mounting surface 31A of the substrate 31 on which the casing 16 is mounted is viewed from above, this circle D overlaps with the reference circle C. In addition, three yokes 15 are arranged on the mounting surface 31A of the substrate. The three yokes 15 are arranged on the outer periphery of the magnetic field forming member 2 at intervals of 120 degrees in the rotation direction of the magnetic field forming member 2. In addition, each yoke 15 is arranged on the inner periphery of the magnetic sensor 4 so as to be adjacent to the magnetic sensor 4.

[0048] In this way, simply by mounting the casing 16 on the mounting surface 31A of the substrate 31, the predetermined positional relationship between the magnetic field forming member 2, the three magnetic sensors 4, and the three yokes 15 for detecting the rotation of the rotating shaft 40 is determined at once.

[0049] (Magnetic field detection operation of magnetic sensors, etc.) 11(A) shows the positional relationship between the magnetic field forming member 2, three magnetic sensors 4, and three yokes 15 when the magnetic sensor device 3 is mounted on the substrate 31. Below, the magnetic field detection operation of the magnetic sensor 4 and the yoke 15 will be described, focusing on one magnetic sensor 4 and one yoke 15 arranged on the upper side among the three magnetic sensors 4 and three yokes 15 in FIG.

[0050] In FIG. 11(A), the S pole of the magnetic field forming member 2 approaches the left front of one of the upper magnetic sensors 4, and the N pole of the magnetic field forming member 2 approaches the right front of the magnetic sensor 4. When the rotating shaft 40 rotates 90 degrees clockwise from this state, as shown in FIG. 11(B), the N pole of the magnetic field forming member 2 approaches the left front of the magnetic sensor 4, and the S pole of the magnetic field forming member 2 approaches the right front of the magnetic sensor 4. At this time, the direction of the magnetic field acting on the magnetic wire 5 of the magnetic sensor 4 becomes rightward. As a result, the magnetization direction of the magnetic wire 5, which was leftward until just before, is suddenly reversed to the right. As a result, as shown in FIG. 11(D), for example, a positive current pulse P1 is generated in the coil 12.

[0051] After that, when the rotating shaft 40 rotates further clockwise by 90 degrees, the S pole of the magnetic field generating member 2 approaches the left front side of the magnetic sensor 4, and the N pole of the magnetic field generating member 2 approaches the right front side of the magnetic sensor 4, as shown in FIG. 11(C). At this time, the direction of the magnetic field acting on the magnetic wire 5 of the magnetic sensor 4 becomes leftward. As a result, the magnetization direction of the magnetic wire 5, which was rightward until just before, is suddenly reversed to leftward. As a result, a current pulse P2, for example, in the negative direction, is generated in the coil 12, as shown in FIG. 11(D).

[0052] One end of the insulated wire 13 forming the coil 12 is connected to a detection circuit provided on the substrate 31, for example, via one terminal 14 of the magnetic sensor 4 and one connection pad 33 provided on the mounting surface 31A of the substrate 31. The other end of the insulated wire 13 forming the coil 12 is connected to the detection circuit via the other terminal 14 of the magnetic sensor 4 and another connection pad 33 provided on the mounting surface 31A of the substrate 31. With this configuration, the current pulses P1 and P2 generated in the coil 12 are output to the detection circuit as pulse signals.

[0053] The detection circuit detects the amount and direction of rotation of the rotating shaft 40 based on pulse signals output from the coils 12 of the three magnetic sensors 4 arranged on the mounting surface 31A of the substrate 31. Note that the method of detecting the amount and direction of rotation of the rotating shaft 40 in the rotation detection device 1 may be, for example, the method described in International Publication No. WO 2016 / 002437.

[0054] In order to increase the level of the current pulse generated in the coil 12 or to sharpen the waveform of the current pulse, it is preferable to concentrate the magnetic flux of the magnetic field formed by the two magnetic poles of the magnetic field forming member 2 close to the left front and right front of the magnetic sensor 4 on the magnetic wire 5. As shown in FIG. 11(B) or 11(C), a yoke 15 is disposed between the magnetic sensor 4 and the magnetic field forming member 2. The yoke 15 controls the direction of the magnetic flux so that the magnetic flux of the magnetic field formed by the two magnetic poles of the magnetic field forming member 2 close to the left front and right front of the magnetic sensor 4 is concentrated on the magnetic wire 5. The arrows F in FIG. 11(B) and 11(C) indicate the flow of the magnetic flux whose direction is controlled by the yoke 15. By concentrating the magnetic flux on the magnetic wire 5 by the yoke 15, the magnetic flux flows along the extension direction of the magnetic wire 5, and the magnetic flux is surely passed through the magnetic wire 5.

[0055] As described above, in the magnetic sensor device 3 according to the embodiment of the present invention, the three magnetic sensors 4 are fixed in the casing 16, and the three magnetic sensors 4 are arranged on the reference plane S located in the same plane as the lower surface of the casing 16 at intervals of 120 degrees around the reference line Q perpendicular to the reference plane S, so that the extension direction of the magnetic wire 5 is parallel to the reference plane S, and so that the center part in the extension direction of the magnetic wire 5 is in contact with the reference circle C when the casing 16 is viewed from above. In this way, in the magnetic sensor device 3 according to the embodiment, the arrangement between the three magnetic sensors 4 for detecting the rotation of the rotating shaft 40 is determined and fixed in the casing 16, so that the arrangement between the three magnetic sensors 4 for detecting the rotation of the rotating shaft 40 is determined on the mounting surface 31A of the substrate 31 by mounting the casing 16 on the mounting surface 31A of the substrate 31. Therefore, according to the magnetic sensor device 3 according to the embodiment, it is possible to suppress the misalignment between the three magnetic sensors 4, compared to the conventional technology in which the three magnetic sensors are individually mounted on the substrate.

[0056] Furthermore, according to the magnetic sensor device 3 of this embodiment, a predetermined positional relationship between the magnetic field forming member 2 and the three magnetic sensors 4 for detecting the rotation of the rotating shaft 40 is determined at once simply by mounting the casing 16 on the mounting surface 31A of the substrate 31. Therefore, compared to the conventional technology in which the three magnetic sensors are individually mounted on the substrate, the effort required for mounting the magnetic sensors can be reduced.

[0057] In the magnetic sensor device 3 of this embodiment, three yokes 15 corresponding one-to-one to the three magnetic sensors 4 are fixed in the casing 16 together with the three magnetic sensors 4. According to the magnetic sensor device 3 of this embodiment having such a configuration, the three yokes 15 can be arranged on the mounting surface 31A of the substrate 31 simply by mounting the casing 16 on the mounting surface 31A of the substrate 31, and the magnetic flux of the magnetic field formed by the magnetic field forming member 2 can be concentrated on the magnetic wire 5 of each magnetic sensor 4. Therefore, compared with the case where the three yokes are mounted individually on the substrate, it is possible to suppress misalignment between the yokes and the magnetic sensors, and also to reduce the effort required for mounting the yokes.

[0058] In the magnetic sensor device 3 of this embodiment, the multiple yokes are integrated with the casing by insert molding. This allows the yoke 15 to be firmly fixed inside the casing, and the position of the yoke inside the casing 16 to be determined with high precision, thereby enhancing the effect of suppressing misalignment between the yoke and the magnetic sensor.

[0059] In the magnetic sensor device 3 of this embodiment, the inner diameter of the connecting portion 18 of the casing 16 is equal to the diameter of the through hole 31B of the substrate 31. As a result, by disposing the casing 16 on the mounting surface 31A of the substrate 31 so that the inner surfaces of the connecting portion 18 and the through hole 31B are aligned with each other, the mounting position of the casing 16 on the substrate 31 can be accurately determined.

[0060] Furthermore, according to this embodiment, the arrangement of the magnetic field forming member 2, the three magnetic sensors 4, and the three yokes 15 for detecting the rotation of the rotating shaft 40 is determined simply by mounting the casing 16 on the mounting surface 31A of the substrate 31, so that a rotation detection device 1 with high rotation detection accuracy can be easily manufactured.

[0061] In the above embodiment, the three magnetic sensors 4 are arranged at 120 degree intervals and the three yokes 15 are arranged at 120 degree intervals in the casing 16 of the magnetic sensor device 3, but the intervals at which the three magnetic sensors are arranged and the intervals at which the three yokes 15 are arranged are not limited to this. For example, as shown in Fig. 12, the three magnetic sensors 4 may be arranged at 60 degree intervals and the three yokes 15 may be arranged at 60 degree intervals in the casing 52 of the magnetic sensor device 51.

[0062] In addition, the number of magnetic sensors provided in the casing of the magnetic sensor device of the present invention is not limited to three, but may be two, four or more. The same applies to the yoke. It is also possible to configure the magnetic sensor device of the present invention without providing a yoke in the casing.

[0063] In the above embodiment, the three magnetic sensors 4 are arranged in the casing 16 so that the center of the magnetic wire 5 in the extension direction is in contact with the reference circle C when the casing 16 is viewed from above. However, the present invention is not limited to this. For example, as shown in FIG. 13, the three magnetic sensors 4 may be arranged so that the magnetic wire 5 of each magnetic sensor 4 intersects with the circumference of the reference circle C. In this arrangement, the arrangement of the magnetic field forming member (magnetic pole or magnet for forming a rotating magnetic field) in the rotation detection device will also be different. For the arrangement of the magnetic field forming member, refer to JP 2019-200098 A. In addition, other aspects can be adopted for the arrangement of the multiple magnetic sensors in the magnetic sensor device of the present invention.

[0064] In the above embodiment, the reference plane S is a plane located in the same plane as the bottom surface of the casing 16, but the present invention is not limited to this. The reference plane S may be a plane that is parallel to the bottom surface of the casing 16 and located above or below the bottom surface of the casing 16.

[0065] When the reference plane S is a plane parallel to the bottom surface of the casing 16 and located above the bottom surface of the casing 16, when each magnetic sensor 4 is mounted in the sensor receiving hole 19 of the casing 16, the bottom surface of each wire support portion 8 of the bobbin 6 of the magnetic sensor 4 is located above the bottom surface of the casing 16. As a result, when the bottom surface of the casing 16 is placed on the mounting surface 31A of the board 31, the bottom surface of each wire support portion 8 of the bobbin 6 of each magnetic sensor 4 is located above the mounting surface 31A of the board 31, and the board connection portion 14B of each terminal 14 of each magnetic sensor 4 does not contact the connection pad 33 on the mounting surface 31A of the board 31. Therefore, when the reference plane S is a plane located above the bottom surface of the casing 16, the position of the board connection portion 14B of each terminal 14 of each magnetic sensor 4 is lowered below the bottom surface of the wire support portion 8, so that the vertical position of the bottom surface of the board connection portion 14B of each terminal 14 coincides with the vertical position of the bottom surface of the fixing bracket 22. As a result, when the underside of the casing 16 is placed on the mounting surface 31A of the substrate 31, the substrate connection portions 14B of each terminal 14 of each magnetic sensor 4 and each fixing bracket 22 simultaneously come into contact with the connection pads 33 and fixing pads 32 on the mounting surface 31A of the substrate 31, respectively, making it possible to solder the substrate connection portions 14B of each terminal 14 of each magnetic sensor 4 and each fixing bracket 22 to the connection pads 33 and fixing pads 32, respectively.

[0066] On the other hand, if the reference plane S is a plane that is parallel to the bottom surface of the casing 16 and is located below the bottom surface of the casing 16, when each magnetic sensor 4 is mounted in the sensor receiving hole 19 of the casing 16, the bottom surface of each wire support portion 8 of the bobbin 6 of the magnetic sensor 4 is located below the bottom surface of the casing 16. As a result, when mounting the casing 16 on the mounting surface 31A of the board 31, the bottom surface of each wire support portion 8 of the bobbin 6 of each magnetic sensor 4 is placed on the mounting surface 31A of the board 31. At this time, the bottom surface of the casing 16 is disposed above the mounting surface 31A of the board 31 and parallel to the mounting surface 31A of the board 31. As a result, each fixing metal fitting 22 of the casing 16 does not contact the fixing pad 32 on the mounting surface 31A of the board 31. Therefore, when the reference plane S is set to a plane located below the bottom surface of the casing 16, the lower part of each fixing metal fitting 22 is lowered below the bottom surface of the casing 16 so that the vertical position of the bottom surface of the fixing metal fitting 22 coincides with the vertical position of the bottom surface of the board connection part 14B of each terminal 14. As a result, when the bottom surface of each wire support part 8 of each magnetic sensor 4 is placed on the mounting surface 31A of the board 31, the board connection part 14B of each terminal 14 of each magnetic sensor 4 and each fixing metal fitting 22 come into contact with the connection pad 33 and the fixing pad 32 on the mounting surface 31A of the board 31 at the same time, respectively, and the board connection part 14B of each terminal 14 of each magnetic sensor 4 and each fixing metal fitting 22 can be soldered to the connection pad 33 and the fixing pad 32, respectively.

[0067] In addition, in the above embodiment, the casing 16 (52) of the magnetic sensor device 3 (51) is structured to connect three sensor holding portions 17 via connecting portions 18, but the structure of the casing of the magnetic sensor device of the present invention is not limited to this and may be, for example, a block or plate shape.

[0068] In the above embodiment, the casing 16 to which the three magnetic sensors 4 and the three yokes 15 are fixed is placed on the substrate 31 and fixed to the substrate 31, thereby providing the three magnetic sensors 4, the three yokes 15, and the casing 16 on the substrate 31. However, the present invention is not limited to this. For example, after the casing 16 to which the three magnetic sensors 4 and the three yokes 15 are separably fixed is placed on the substrate 31, the magnetic sensors 4 and the yokes 15 are firmly fixed to the substrate 31, but the casing 16 may not be fixed to the substrate 31, and after the magnetic sensors 4 and the yokes 15 are firmly fixed to the substrate 31, the casing 16 may be removed from the substrate 31 while leaving the three magnetic sensors 4 and the three yokes 15 on the substrate 31.

[0069] In this case, for example, the yoke 15 is fixed to each of the three magnetic sensors 4 so that it cannot be easily separated, and the three magnetic sensors 4 to which the yoke 15 is fixed are fixed in three sensor housing holes provided on the lower surface of the casing 16 so that they can be easily separated. When assembling the rotation detection device, first, as shown in FIG. 14(A), the casing 16 to which the three magnetic sensors 4 to which the yoke 15 is fixed are fixed so that they can be easily separated is placed on the mounting surface 31A of the substrate 31. Next, as shown in FIG. 14(B), the substrate connection portion 14B of each terminal 14 of each magnetic sensor 4 is soldered to the connection pad 33 on the mounting surface 31A of the substrate 31. As a result, the three magnetic sensors 4 to which the yoke 15 is fixed are firmly fixed to the substrate 31. Next, as shown in FIG. 14(C), the casing 16 is pulled upward from the substrate 31. As a result, the casing 16 is separated from the three magnetic sensors 4 soldered to the substrate 31 and the three yokes 15 fixed to the three magnetic sensors 4 so that they cannot be easily separated, and the three magnetic sensors 4 and the three yokes 15 remain on the mounting surface 31A of the substrate 31. As a method for fixing the yokes 15 to the three magnetic sensors 4 so that they cannot be easily separated, for example, a method of adhering the yokes 15 to the wire support parts 8 of the bobbins 6 of the magnetic sensors 4 with an adhesive can be used. In addition, the sensor housing hole formed on the lower surface of the casing 16 is made larger than the sensor housing hole 19 in the above embodiment so that the magnetic sensor 4 to which the yokes 15 are fixed can be mounted in the casing 16. In addition, in order to make it easy to separate the magnetic sensor 4 to which the yokes 15 are fixed and the casing 16 from each other, for example, the height of each protrusion formed on the rear surface of the sensor housing hole of the casing 16 is made lower than the protrusion 21 in the embodiment so that the magnetic sensor 4 to which the yokes 15 are fixed can be easily removed from the sensor housing hole. Furthermore, since the casing 16 is removed from the board 31 after the three magnetic sensors 4 with the yokes 15 fixed thereto are soldered to the board 31, no fixing brackets 22 are provided on the casing 16. When mounting components on a board, a mounting device equipped with a suction nozzle may be used to move and position the components on the board.As shown in FIG. 14(A), it is preferable to close the upper portion of the connecting portion 18 of the casing 16 and form a suction surface 23 in the center of the upper surface of the casing 16 for suctioning the casing 16 with a suction nozzle.

[0070] Furthermore, the present invention can be modified as appropriate within the scope that does not contradict the gist or concept of the invention that can be read from the claims and the entire specification, and magnetic sensor devices and rotation detection devices involving such modifications are also included in the technical concept of the present invention. [Explanation of symbols]

[0071] 1 Rotation detection device 2 Magnetic field forming member 3, 51 Magnetic sensor device 4 Magnetic Sensor 5 Magnetic wire 12 Coils 15 York 16, 52 Casing 31 Substrate 31A Mounting surface 40 Rotating shaft (rotating body) Q Reference Line S reference plane

Claims

1. a magnetic wire that exhibits a large Barkhausen effect and a plurality of magnetic sensors each having a coil disposed on an outer periphery of the magnetic wire; a casing to which the plurality of magnetic sensors are respectively fixed; A magnetic sensor device characterized in that the multiple magnetic sensors are arranged on a single reference plane that is the same as or parallel to the underside of the casing, at a predetermined interval circumferentially around a reference line perpendicular to the reference plane, and such that the extension direction of the magnetic wire is parallel to the reference plane.

2. A plurality of yokes are provided for controlling the direction of the magnetic flux of an external magnetic field; the plurality of yokes are provided in one-to-one correspondence with the plurality of magnetic sensors, 2. The magnetic sensor device according to claim 1, wherein the plurality of yokes are fixed to the casing together with the plurality of magnetic sensors.

3. 3. The magnetic sensor device according to claim 2, wherein the plurality of yokes are integrated with the casing by insert molding.

4. A rotation detection device for detecting rotation of a rotating body, comprising: The magnetic sensor device according to claim 1 ; a magnetic field generating member that rotates together with the rotor and generates a rotating magnetic field on an outer periphery of the rotor when the rotor rotates; a substrate having a mounting surface, the substrate being disposed in the vicinity of the magnetic field generating member such that the mounting surface faces upward, a plane including the mounting surface is perpendicular to the rotation axis, and the substrate is not in contact with either the rotor or the magnetic field generating member; A rotation detection device characterized in that the casing of the magnetic sensor device is fixed to the substrate with the reference line coinciding with the rotation axis of the rotating body and the lower surface of the casing being parallel to the mounting surface and positioned on or above the mounting surface.

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