Power generation sensor

Abstract

To provide a power generation sensor which can be easily combined with magnetic field generation sources differing in shape and / or pole number, and with which a high power signal can be obtained.SOLUTION: A power generation sensor 100 includes a magnetic wire 110 that exhibits a large Barkhausen effect by an alternating magnetic field applied in an axial direction x, a coil 120 that is wound around the magnetic wire, and a pair of magnetic flux conduction pieces 130, 131 that are magnetically joined to both ends of the magnetic wire, respectively. The pair of magnetic flux conduction pieces are provided with a pair of axis orthogonal parts 133 that extend in parallel to each other in a direction z that is orthogonal to the axial direction and a pair of axis parallel parts 134 that extend in a mutually approaching direction along the axial direction from the tips of the axis orthogonal parts. The distance L of the interval in the axial direction between proximal ends 134a of the pair of axis parallel parts is 5% to 50% of the distance D in the axial direction between the pair of axis orthogonal parts at a connected position with the magnetic wire. The power generation sensor is constituted such that the side of the axis parallel parts that is opposite the magnetic wire is a detection region 140.SELECTED DRAWING: Figure 1B

Description

[Technical Field]

[0001] The present invention relates to a power generating sensor that generates electric power in response to a change in a magnetic field. [Background technology]

[0002] Magnetic wire with a large Barkhausen effect (large Barkhausen jump) is known as Wiegand wire or pulse wire. This magnetic wire has a core and a skin surrounding the core. One of the core and skin is a soft (soft magnetic) layer whose magnetization direction reverses even in a weak magnetic field, while the other is a hard (hard magnetic) layer whose magnetization direction does not reverse unless a strong magnetic field is applied. A power generating sensor can be constructed by winding a coil around such a magnetic wire.

[0003] When the hard and soft layers are magnetized in the same direction along the axial direction of the wire, the magnetization direction of the soft layer is reversed when the external magnetic field strength in the opposite direction increases and reaches a certain magnetic field strength. This reversal of the magnetization direction starts at a certain point in the magnetic wire and propagates throughout the wire, causing the magnetization direction of the soft layer to reverse simultaneously. At this time, the large Barkhausen effect occurs, inducing a pulse signal in the coil wound around the magnetic wire. When the external magnetic field strength is further increased and reaches a certain magnetic field strength, the magnetization direction of the hard layer is reversed.

[0004] In this specification, the magnetic field strength when the magnetization direction of the soft layer is reversed is called the "operating magnetic field," and the magnetic field strength when the magnetization direction of the hard layer is reversed is called the "stabilizing magnetic field."

[0005] The output voltage obtained from the coil is constant regardless of the speed at which the input magnetic field (external magnetic field) changes, and has hysteresis characteristics with respect to the input magnetic field, so there is no chattering. For this reason, the pulse signal generated from the coil is used in position detection devices, etc. As the output from the coil contains power, it can be used to create a power-generating sensor (power-generating sensor) that does not require an external power supply.

[0006] For the large Barkhausen effect to occur, the magnetization direction of only the soft layer must be reversed from a state in which the magnetization directions of the hard and soft layers are aligned. Even if the magnetization direction of only the soft layer is reversed when the magnetization directions of the hard and soft layers are not aligned, no pulse signal will be generated, or even if it is generated, it will be very small.

[0007] Furthermore, to maximize the power output, it is important that the magnetization direction of the entire magnetic wire is aligned, and that the magnetization reversal of the soft layer extends across the entire magnetic wire. If the magnetization direction of the magnetic wire is not aligned in parts, only a very small pulse signal is obtained. Therefore, it is preferable that a uniform magnetic field is applied to the entire magnetic wire.

[0008] Patent Documents 1 to 5 describe techniques for power generation sensors and / or position detection devices using power generation sensors.

[0009] Patent Document 1 discloses a magnetic sensor equipped with cylindrical soft magnetic magnets on both ends of a magnetic wire. It explains that this configuration can suppress the demagnetizing field generated in the magnetic wire and stabilize the pulse signal output. However, unless the magnetic field generating source is structured to apply a magnetic field parallel to the axial direction of the magnetic wire to the entire magnetic wire, the large Barkhausen effect inherent to the magnetic wire cannot be fully induced.

[0010] Patent Document 2 discloses a power generating element having soft magnetic bodies at both ends of a magnetic wire, which contact the magnetic wire and press against it. It explains that this configuration can suppress the demagnetizing field generated in the magnetic wire and stabilize the pulse signal output. However, the soft magnetic body structure disclosed in Patent Document 2 is only weakly effective in inducing and / or shielding the magnetic field leaking from the magnet that generates the external magnetic field. As a result, a magnetic field parallel to the axial direction of the magnetic wire is not applied to the entire axis of the magnetic wire. Therefore, the large Barkhausen effect inherent to the magnetic wire cannot be fully exerted, and high output cannot be expected.

[0011] Patent Documents 3 to 5 disclose techniques for obtaining high output by applying a magnetic field leaking from a magnet, which is a detection medium, parallel to the axial direction of the magnetic wire to the entire axis of the magnetic wire.

[0012] Patent Document 3 discloses a rotation speed detector that includes a magnet attached to a rotor that rotates around a rotation axis and a power generating element. The power generating element is constructed by attaching ferrite beads to both ends of a magnetic wire and winding a coil around the magnetic wire between them. The magnet has multiple magnetic poles aligned in the direction of rotation, each with a first region and a second region with different magnetic strengths. The magnet and power generating element are arranged facing each other in a direction parallel to the rotation axis in an offset region from the rotation axis. The ferrite bead attracts magnetic flux from the magnet toward the magnetic wire and transmits it to the magnetic wire through the ferrite bead. To achieve this effect, the magnet shape and the gap (air gap) between the magnet and the power generating element must be carefully designed to ensure that a magnetic field of appropriate strength is applied to the magnetic wire depending on the rotation angle of the rotation axis. This makes the design of the power generating sensor difficult and limits the design flexibility of the magnet shape.

[0013] Patent Document 4 discloses a rotation detection device including a magnetic field detector having a coil wound around a magnetic wire. Four permanent magnets are fixed to the outer periphery of a shaft rotatably supported in a housing, and three magnetic field detectors are arranged outside the rotation locus circle of the permanent magnet. The three magnetic field detectors are arranged so that their axial directions are parallel to the tangent direction of the rotation locus circle and can face the permanent magnet along the radial direction of the rotation locus circle. The magnetic field detectors are fixed to a substrate, which is fixed to the housing. A first magnetic member and a second magnetic member are also fixed to the substrate. The first magnetic member is arranged at a distance from the magnetic field detector and is arranged on one axial side of the magnetic field detector so as to cover a portion facing the permanent magnet. The second magnetic member is arranged at a distance from the magnetic field detector and is arranged on the other axial side of the magnetic field detector so as to cover a portion facing the permanent magnet. It is described that these magnetic members can induce the magnetic field applied to the magnetic field detector by the permanent magnet and form a predetermined magnetic path.

[0014] However, in the structure shown in FIG. 1 of Patent Document 4, the two magnetic members are arranged at a distance from both ends of the magnetic wire, so the magnetic coupling is weak and the induction efficiency is not high.

[0015] In the structure shown in Figure 4 of Patent Document 4, side plates are added, increasing the area of ​​the magnetic member facing the magnetic field detector, improving induction efficiency. However, because the side plates are positioned away from both ends of the magnetic wire, the effect is insufficient, and additional side plates are required to face the magnetic field detector from the opposite side of the permanent magnet. Furthermore, as shown in Figures 3A and 5 of Patent Document 4, the magnetic field is curved, and magnetic flux enters and exits the middle part of the magnetic wire, so the magnetic field strength throughout the magnetic wire is not uniform. Furthermore, the magnetic member in Patent Document 4 must be shaped to match the shape and placement of the permanent magnet, which makes it less versatile.

[0016] Patent Document 5 discloses an electric signal generating unit configured to induce a magnetic field from a magnet using first and third magnetic bodies with elongated notches that accommodate the ends of a magnetically sensitive portion made of a magnetically sensitive wire. Because the ends of the magnetically sensitive portion are directly installed in the notches of the first and third magnetic bodies, induction efficiency is high. However, the first and third magnetic bodies are not designed to block magnetic fields that leak from the magnet and reach the center of the axis of the magnetically sensitive portion. Therefore, the magnet must be covered by a side yoke, which serves as the second magnetic body. This results in a large number of parts and a large structure. Furthermore, although both ends of the first and third magnetic bodies are inclined inward or outward, the inclination angle and length must be designed to match the shape and arrangement of the magnet, resulting in a lack of versatility. Furthermore, both ends of the magnetically sensitive portion must be accommodated in the notches of the first and third magnetic bodies during assembly and adjustment. In other words, both ends of the magnetically sensitive part are adjusted and positioned (based on the quality of the workmanship) using the notches in the first and third magnetic bodies during assembly. Therefore, not only is the assembly of the device complicated, but the performance of the device depends on the assembly precision. [Prior art documents] [Patent documents]

[0017] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-73974 [Patent Document 2] International Publication No. 2021 / 200361 [Patent Document 3] Patent No. 6647478 [Patent Document 4] Patent No. 6407284 [Patent Document 5] Patent No. 6959588 Summary of the Invention [Problem to be solved by the invention]

[0018] Thus, to apply a magnetic field parallel to the axial direction with uniform strength to the entire magnetic wire, simply placing a power generating sensor is not enough; various magnetic bodies designed according to the overall configuration of the detection device must be placed between the power generating sensor and the magnet. Specifically, magnetic members with shapes and positions that match the structure and / or position of the magnet, which is the detection medium, are required. Therefore, the structures of the prior art generally have the disadvantage of lacking versatility.

[0019] Therefore, one embodiment of the present invention provides a power generation sensor having a structure that can improve versatility.

[0020] More specifically, one embodiment of the present invention provides a power generating sensor that can be easily combined with magnetic field generating sources (typically magnets) having different shapes and / or numbers of poles and can obtain a high output signal. [Means for solving the problem]

[0021] One embodiment of the present invention provides a power generating sensor including a magnetic wire that exhibits a large Barkhausen effect when an alternating magnetic field is applied in the axial direction, a coil wound around the magnetic wire, and a pair of magnetic flux conducting pieces, each consisting of a pair of soft magnetic components magnetically coupled to both ends of the magnetic wire, the pair being symmetrical with respect to a symmetry plane set at the center of the axial direction of the magnetic wire. The pair of magnetic flux conducting pieces includes a pair of axis-orthogonal portions to which both ends of the magnetic wire are fixed, extending parallel to each other in a direction perpendicular to the axial direction from both ends of the magnetic wire, and a pair of axis-parallel portions extending from tips of the axis-orthogonal portions toward each other along the axial direction, with proximal ends facing each other with a gap in the axial direction. The axial distance between the proximal ends is 5% to 50% of the axial distance between the pair of axis-orthogonal portions at the coupling position with the magnetic wire. The power generating sensor is configured so that a detection region is located on the side opposite the magnetic wire with respect to the axis-parallel portions.

[0022] According to this configuration, the magnetic field in the detection region is guided to both ends of the magnetic wire by the magnetic flux conduction pieces made of soft magnetic material. Furthermore, because an axially parallel portion parallel to the axial direction of the magnetic wire is located between the detection region and the magnetic wire, the magnetic flux traveling from the detection region to a midpoint in the axial direction of the magnetic wire is shielded by the axially parallel portion. In particular, the axial distance between the adjacent ends of the axially parallel portions of a pair of magnetic flux conduction pieces is 5% to 50% of the distance between the axially perpendicular portions at the coupling position with the magnetic wire, resulting in an excellent magnetic shielding effect. Therefore, since the axial magnetic field can be applied over a wide range in the axial direction of the magnetic wire, the large Barkhausen effect can be fully induced, resulting in a power generating sensor that can generate a high-output signal.

[0023] Furthermore, since the power generating sensor includes a magnetic flux conducting piece that is fixedly connected to the magnetic wire, it is sufficient to place a magnetic field generating source (typically a magnet) as a detection medium in the detection area. This makes it easy to combine magnetic field generating sources with different shapes and / or polarities, facilitating the design of devices (such as position detection devices) that utilize such combinations.

[0024] In one embodiment, the pair of magnetic flux conducting pieces are configured to correct a magnetic field generated in a space including the pair of magnetic flux conducting pieces by a magnetic field generating source located in the detection region into the axial magnetic field and apply the corrected magnetic field to the magnetic wire. With this configuration, the magnetic flux conducting pieces have a magnetic field correcting function for correcting the magnetic field from the magnetic field generating source located in the detection region, thereby applying an axial magnetic field between both ends of the magnetic wire. This allows the large Barkhausen effect to be fully utilized, thereby generating a high-power pulse signal.

[0025] In one embodiment, the axial distance of the gap is 20% to 40% of the axial distance between the pair of axis-orthogonal portions at the coupling position with the magnetic wire. With this configuration, the large Barkhausen effect inherent to the magnetic wire can be almost fully utilized, thereby realizing a power generating sensor with even higher output.

[0026] In one embodiment, the axially orthogonal portion of the magnetic flux conducting piece has a wire placement portion having a hole or groove formed therein that penetrates in the axial direction, and the magnetic wire passes through the axially orthogonal portion in the wire placement portion and is fixed to the axially orthogonal portion.

[0027] According to this configuration, by configuring the magnetic wire to pass through the axially orthogonal portion, the magnetic flux conducting piece and both ends of the magnetic wire can be reliably magnetically coupled, and the fixation between them can be reliably achieved.

[0028] The axis-orthogonal portion can be configured to be approximately the same size as the diameter of the coil. In this case, the axis-parallel portion is disposed between the magnetic wire and the detection area, so when the magnetic flux conduction piece is viewed from the axial direction of the magnetic wire, the wire placement portion is disposed in a position offset (biased) away from the detection area. This configuration has the advantage of allowing the power generation sensor to be configured compactly.

[0029] In one embodiment, the thickness of the axis-orthogonal portion in the axial direction at the position where it is joined to the magnetic wire is 10% to 20% of the total length of the magnetic wire. This configuration prevents the magnetic path in the axis-orthogonal portion from becoming too narrow, and prevents a substantial decrease in pickup efficiency of the Large Barkhausen effect due to the axis-orthogonal portion. This makes it possible to realize a power generating sensor capable of generating a high-output pulse signal.

[0030] In one embodiment, the soft magnetic component is made of a material whose coercive force is equal to or less than that of the magnetic wire and whose magnetic permeability is 500 or more. Such a material has properties such as low magnetic resistance, low hysteresis, and low self-dielectric property. As a result, even when a high-frequency alternating magnetic field generated when a magnetic field generating source moves at high speed is applied, the output characteristics of the power generation sensor are less affected. Specifically, the soft magnetic component is preferably made of a Ni-based ferrite or Mn-based ferrite material.

[0031] In one embodiment, the power generating sensor further includes a surface-mounted external terminal electrode provided on the axially parallel portion of the magnetic flux conducting piece so as to face the detection area. This configuration reduces the number of components of the power generating sensor, thereby providing a surface-mounted power generating sensor with a simple structure and a small size. [Effects of the Invention]

[0032] This invention provides a power generating sensor with a structure that can improve versatility. More specifically, it provides a power generating sensor that can be easily combined with magnetic field generating sources (typically magnets) with different shapes and / or numbers of poles and that can obtain high-output signals. [Brief explanation of the drawings]

[0033] [Figure 1A] FIG. 1A is a perspective view of a power generation sensor according to a first embodiment. [Figure 1B] FIG. 1B is a front view looking in the direction of arrow 101 in FIG. 1A. [Figures 2A-2C] 2A, 2B, and 2C show first models of rotation detection devices using the power generation sensor of the first comparative example, the power generation sensor of the second comparative example, and the power generation sensor of the first embodiment, respectively. [Figure 3A-3C] 3A, 3B, and 3C are schematic cross-sectional views showing the results of two-dimensional magnetic simulations in the arrangements shown in FIGS. 2A, 2B, and 2C, respectively. [Figures 4A-4C] 4A, 4B, and 4C show the results of a three-dimensional magnetic simulation for the arrangements (first model) shown in FIGS. 2A, 2B, and 2C, respectively. [Figure 5A-5B] 5A and 5B show second models of rotation detection devices using the power generation sensor of the second comparative example and the power generation sensor of the first embodiment, respectively. [Figures 6A-6C]Figures 6A and 6B show the results of a three-dimensional magnetic simulation in the arrangement shown in Figure 5A (the second model using the power generating sensor of the second comparative example), and Figure 6C shows the results of a three-dimensional magnetic simulation in the arrangement shown in Figure 5B (the second model using the power generating sensor of the first embodiment). [Figures 7A-7B] 7A and 7B show a third model of a rotation detection device using the power generation sensor of the first embodiment. [Figure 8] FIG. 8 shows the results of a three-dimensional magnetic simulation of the arrangement shown in FIG. 7B. [Figure 9] Figure 9 shows the results of an investigation into the relationship between the ratio of the distance between the proximal ends to the distance at the position of the magnetic wire between a pair of magnetic flux conducting pieces and the wave height of the pulse signal output from the coil for the structures of the first model (see Figure 2C) and the third model (see Figure 7B) using the power generating sensor of the first embodiment. [Figure 10] FIG. 10 shows a modification of the first embodiment. [Figure 11A] FIG. 11A is a perspective view of the power generation sensor according to the second embodiment. [Figure 11B] FIG. 11B is a partially exploded perspective view of the power generation sensor according to the second embodiment. [Figure 11C] FIG. 11C is a side view of the power generation sensor according to the second embodiment. [Figures 12A-12C] 12A and 12B are front views showing examples of the configuration of the magnetic flux conduction piece, and Fig. 12C is a perspective view showing the configuration of a modified magnetic flux conduction piece. [Figure 13A] FIG. 13A is a perspective view showing the configuration of a modified example of the power generation sensor according to the second embodiment. [Figure 13B] FIG. 13B is an exploded perspective view showing the configuration of a modified example of the power generation sensor according to the second embodiment. [Figures 14A-14B] 14A and 14B are a perspective view and a plan view, respectively, showing a first configuration example of a rotation detection device using a power generation sensor according to the second embodiment. [Figures 15A-15B]15A and 15B are a perspective view and a plan view, respectively, showing a second configuration example of a rotation detection device using a power generation sensor according to the second embodiment. [Figures 16A-16B] 16A and 16B are a perspective view and a plan view, respectively, showing a third configuration example of a rotation detection device using the power generation sensor according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0034] The present invention will be described below based on the illustrated embodiments, but the present invention is not limited to the embodiments described below.

[0035] [First embodiment] 1A and 1B show a power generating sensor 100 according to a first embodiment. Fig. 1A is a perspective view of the power generating sensor 100, and Fig. 1B is a front view seen in the direction of an arrow 101 in Fig. 1A.

[0036] The power generating sensor 100 includes a magnetic wire 110 that exhibits the large Barkhausen effect, a coil 120 wound around the magnetic wire 110, and a pair of magnetic flux conducting pieces 130 and 131 made of soft magnetic material. The coil 120 is wound around the magnetic wire 110 so that the first end 111 and the second end 112 of the magnetic wire 110 are exposed at the same length. In this embodiment, the coil 120 is wound around the magnetic wire 110 between the pair of magnetic flux conducting pieces 130 and 131. The pair of magnetic flux conducting pieces 130 and 131 are magnetically coupled to the first end 111 and the second end 112 of the magnetic wire 110, respectively.

[0037] The pair of magnetic flux conduction pieces 130, 131 have a configuration that is substantially the same shape and same size. More specifically, the pair of magnetic flux conduction pieces 130, 131 are configured symmetrically with respect to a symmetry plane 115 (a virtual plane for explaining the geometric arrangement) perpendicular to the axial direction x at a center position (hereinafter referred to as the "axial center position") 113 in the axial direction x (length direction, wire length direction) of the magnetic wire 110. The pair of magnetic flux conduction pieces 130, 131 include axially orthogonal portions 133 that extend parallel to each other in an orthogonal direction z perpendicular to the axial direction x from both end portions 111, 112 of the magnetic wire 110, and axially parallel portions 134 that extend from the tip ends of the axially orthogonal portions 133 in directions approaching each other along the axial direction x.

[0038] Both ends 111, 112 of the magnetic wire 110 are fixed to the base ends of the axis-orthogonal portions 133 of the pair of magnetic flux conduction pieces 130, 131, respectively. More specifically, the base ends of the axis-orthogonal portions 133 are provided with wire placement sections 130a, 131a, each having a hole or groove formed therethrough in the axial direction x. FIG. 1A and other figures show an example in which the wire placement sections 130a, 131a are formed with a hole. When the wire placement sections 130a, 131a are formed with a groove, the groove preferably extends along the orthogonal direction z so as to open to the end face opposite the detection area 140, which will be described later. The first end 111 and the second end 112 of the magnetic wire 110 are fixed to the axis-orthogonal portions 133 in the wire placement sections 130a, 131a, while passing through the axis-orthogonal portions 133. More specifically, resin (not shown) is placed in the holes or grooves that form the wire placement portions 130a, 131a, whereby the ends 111, 112 of the magnetic wire 110 are fixed to the axis-orthogonal portion 133 and coupled to each other. As a result, the magnetic wire 110 and the pair of magnetic flux conduction pieces 130, 131 are mechanically coupled to each other and magnetically coupled to each other.

[0039] The near ends 134a of the axially parallel portions 134 of the pair of magnetic flux conduction pieces 130, 131 face each other across a plane of symmetry 115 that passes through the axial center position 113 of the magnetic wire 110. That is, the near ends 134a face each other with a gap in the axial direction x. The middle position of this gap in the axial direction x corresponds to the position of the axial center position 113 in the axial direction x, and therefore the distances in the axial direction x from the near ends 134a of the pair of axially parallel portions 134 to the plane of symmetry 115 are equal. The distance L of this gap in the axial direction x is 5% to 50% of the distance D between the pair of axially orthogonal portions 133 at the coupling position between the magnetic wire 110 and the axially orthogonal portions 133, and more preferably 20% to 40%. More specifically, the distance D is the distance in the axial direction x between the inner surfaces 130b, 131b (inner surfaces of the axis-orthogonal portions 133) of the pair of magnetic flux conduction pieces 130, 131 that face each other in the axial direction x at the coupling position with the magnetic wire 110.

[0040] The power generating sensor 100 is configured such that the area on the opposite side of the axially parallel portion 134 from the magnetic wire 110 is the detection area 140. A magnetic field generating source 400 that generates the magnetic field to be detected is arranged in this detection area 140. Typically, the magnetic field generating source 400 moves relative to the power generating sensor 100 so as to pass through the detection area 140. In other words, the detection area 140 is arranged on the movement path of the magnetic field generating source 400. The pair of magnetic flux conducting pieces 130, 131 are configured to correct the magnetic field formed by the magnetic field generating source 400 arranged in the detection area 140 in a space including the magnetic flux conducting pieces 130, 131 into a magnetic field in the axial direction x and apply it to the magnetic wire 110.

[0041] More specifically, the magnetic flux conduction pieces 130, 131, which are made of soft magnetic material, have an axis-orthogonal portion 133 having a substantially rectangular parallelepiped shape and an axis-parallel portion 134 also having a substantially rectangular parallelepiped shape connected to the end of the axis-orthogonal portion 133 facing the magnetic field source 400, i.e., the end on the detection area 140 side, and have an L-shape bent at a right angle at the junction between the axis-orthogonal portion 133 and the axis-parallel portion 134. The axis-parallel portion 134 extends along the axial direction x so as to cover the magnetic wire 110, i.e., to shield the magnetic wire 110 from the detection area 140. The axis-parallel portions 134 of the pair of magnetic flux conduction pieces 130, 131, which are symmetrical to each other, extend toward the axial center of the magnetic wire 110, and their proximal ends 134a face each other with a gap therebetween near the axial center position 113 of the magnetic wire 110. The proximal ends 134a form planes perpendicular to the axial direction x, and the two planes forming each of the two proximal ends 134a are parallel to each other and face each other in the axial direction x. The distance L in the x direction of the spacing between the two proximal ends 134a is the distance between the two planes forming the two proximal ends 134a.

[0042] The magnetic flux conduction pieces 130, 131 and the coil 120, which are made of soft magnetic material parts, are fixed to a case (not shown) that covers them by adhesive resin, fitting, or other appropriate fixing means. As described above, both ends 111, 112 of the magnetic wire 110 are fixed to wire placement sections 130a, 131a, which are made of two through-holes or grooves, by resin (not shown). Therefore, the power generation sensor 100 is configured by a structure in which the pair of magnetic flux conduction pieces 130, 131, the coil 120, and the magnetic wire 110 are fixed to each other and integrated.

[0043] [First model] 2A, 2B, and 2C show first models of a rotation detection device using a power generation sensor 280 of a first comparative example, a power generation sensor 300 of a second comparative example, and the power generation sensor 100 of the first embodiment, respectively. The rotation detection device includes a magnet 410 that rotates around a rotation axis 411, and power generation sensors 280, 300, and 100 that are arranged with their axial center positions 113 aligned with the rotation axis 411 and their axial directions x set to be perpendicular to the rotation axis 411. However, in each figure, the coils 120 (see FIGS. 1A and 1B) of the power generation sensors 280, 300, and 100 are not shown. The magnetic wire 110 is spaced from the magnet 410 in a direction parallel to the rotation axis 411.

[0044] The magnet 410 is an example of the magnetic field generator 400. In this example, the magnet 410 is a ring-shaped two-pole magnet with a diameter smaller than the entire length of the magnetic wire 110, and has a shape that makes it difficult for a magnetic field parallel to the axial direction x of the magnetic wire 110 to be applied to the entire magnetic wire 110. The magnet 410 is a ring-shaped rotating body centered on a rotation axis 411, with half of the circumferential area being an N-pole area and the remaining half being an S-pole area.

[0045] Figures 2A, 2B, and 2C show the magnetic wire 110 arranged so that the magnetic pole boundary line 410a of the NS pole is perpendicular to the axial direction x of the magnetic wire 110 in a planar view along the rotation axis 411, so that a stabilizing magnetic field is applied in the axial direction x of the magnetic wire 110.

[0046] The power generating sensor 280 of the first comparative example shown in FIG. 2A does not include magnetic flux conduction pieces 130, 131 made of soft magnetic material components, as compared with the first embodiment (see FIG. 2C). The power generating sensor 300 of the second comparative example shown in FIG. 2B includes soft magnetic material components 330, 331 at both ends of the magnetic wire 110, as compared with the first embodiment (see FIG. 2C). However, these soft magnetic material components 330, 331 are configured in a cylindrical shape with a through hole in the center through which the magnetic wire 110 passes, and do not have an L-shaped bent portion on the side facing the magnet 410. In other words, the soft magnetic material components 330, 331 are not designed to magnetically shield the magnetic wire 110 from the magnet 410. In short, the power generating sensor 300 of the second comparative example is comparable to the structure shown in FIG. 6 of Patent Document 1. The distance L in the axial direction x between the pair of soft magnetic material parts 330, 331 is equal to the distance D between them at the coupling position with the magnetic wire 110 at any position, and is 100% of this distance D.

[0047] In the power generation sensor 100 of the first embodiment shown in Figure 2C, the distance L in the axial direction x between the proximal ends 134a of the axially parallel portions 134 is, for example, one-third, or 33%, of the distance D between the axially orthogonal portions 133.

[0048] Figures 3A, 3B, and 3C are schematic cross-sectional views showing the results of a two-dimensional magnetic simulation in the arrangements shown in Figures 2A, 2B, and 2C, respectively. Specifically, the results of the two-dimensional magnetic simulation are shown in a vertical cross section passing through the axis of the magnetic wire 110 in the arrangements shown in Figures 2A, 2B, and 2C.

[0049] In order for the magnetic flux distribution of the magnetic wire 110 to be uniform over the entire axial length range, it is desirable for the magnetic flux to enter from one end of the magnetic wire 110 and exit from the other end.

[0050] 3A, most of the magnetic flux generated by the magnetic field generation source (magnet 410) enters and exits from the middle position in the axial direction of the magnetic wire 110. Therefore, the magnetic flux density in the central region of the magnetic wire 110 is higher than that in both end regions.

[0051] From the magnetic simulation results of the second comparative example shown in FIG. 3B, the cylindrical soft magnetic material part 330 ,331 It can be seen that the magnetic flux of the magnetic field generating source (magnet 410) is attracted to the magnetic wire 110, and the amount of magnetic flux that escapes from one end of the magnetic wire 110 to the other end is increased compared to the first comparative example. However, there is still magnetic flux that enters the center of the magnetic wire 110 and escapes at a midpoint in the axial direction.

[0052] The magnetic simulation results for the first embodiment shown in FIG. 3C reveal that most of the magnetic flux from the magnetic field source (magnet 410) is attracted to the magnetic flux conduction pieces 130, 131, which are L-shaped soft magnetic parts. A small portion leaks through the gap (distance L) at the center, but most of the magnetic flux travels along a path from one end of the magnetic wire 110 to the other. The magnetic flux from the magnetic field source (magnet 410) toward the center of the magnetic wire 110 is shielded by the magnetic flux conduction pieces 130, 131, which are soft magnetic parts, and particularly by their axially parallel portions 134. Therefore, no magnetic flux enters the magnetic wire 110 from a midpoint in the axial direction. More specifically, the magnetic flux from the magnetic field source (magnet 410) enters the detection-area-facing surface 134b of the axially parallel portion 134 of one of the magnetic flux conduction pieces 130, and is conducted within the magnetic flux conduction piece 130 to the first end 111 of the magnetic wire 110. Furthermore, the magnetic flux from the second end 112 of the magnetic wire 110 is conducted through the other magnetic flux conduction piece 131 to the axially parallel portion 134, and then reaches the magnetic field source (magnet 410) from the detection area facing surface 134b. Therefore, a uniform magnetic flux distribution is achieved over the entire length of the magnetic wire 110. In other words, a magnetic field of uniform strength that is parallel to the axial direction x can be formed over the entire length of the magnetic wire 110. The detection area facing surface 134b is the surface that faces the detection area 140 and is a surface that is parallel to the axial direction x.

[0053] Thus, in the power generating sensor 100 of the first embodiment, the magnetic flux conducting pieces 130, 131 act to correct the magnetic field generated by the magnetic field source (magnet 410) located in the detection area 140 in the axial direction x of the magnetic wire 110 and apply it to the magnetic wire 110.

[0054] 4A, 4B, and 4C show the results of a three-dimensional magnetic simulation for the arrangements (first model) shown in Fig. 2A, 2B, and 2C, respectively. Using these figures, we will explain the function of correcting the magnetic field applied in the axial direction x of the magnetic wire 110 even when the magnet 410, which is the magnetic field generating source, rotates around the rotation axis 411.

[0055] 4A, 4B, and 4C are graphs showing the magnetic field applied to the magnetic wire 110 at multiple rotation angles of the magnet 410 when the magnet 410 is rotated around the rotation axis 411. The wire position on the horizontal axis represents the position of each part of the magnetic wire 110 in the axial direction x. Specifically, in the arrangements of FIGS. 2B and 2C, the section between the two inner surfaces 130b, 131b (see FIG. 1B) facing each other in the axial direction x of the axis-orthogonal portions 133 of the two magnetic flux conduction pieces 130, 131 is divided into 10 equal parts, with one end of the section represented as "0" and the other end as "10." In the arrangement of FIG. 2A, the corresponding wire positions are also represented as "0" to "10." 2A to 2C is defined as 0 degrees, and the rotation angle of the magnet 410 when the magnetic pole boundary line 410a of the magnet 410 is parallel to the magnetic wire 110 in a plan view of those arrangements is defined as 90 degrees. Note that the total length of the magnetic wire 110 in the first comparative example in FIG. 2A, the second comparative example in FIG. 2B, and the first embodiment in FIG. 2C is the same, and therefore the wire positions shown in FIGS. 4A, 4B, and 4C indicate corresponding positions. The vertical axis represents magnetic field strength.

[0056] Figures 4A, 4B, and 4C show the results of magnetic simulations for the first quadrant of the rotation angle range, i.e., from 0 to 90 degrees. Within this first quadrant, we can see the stabilizing magnetic field that can set the magnetization directions of the hard and soft layers to the same ready state (the set state before a positive signal is output) and the operating magnetic field that can reverse the soft layer to make the magnetization directions of the hard and soft layers opposite (a negative signal is output). The magnetic field strength was normalized so that the stabilizing magnetic field was |±1| or greater. The operating magnetic field was approximately ±0.5. In other words, in Figures 4A, 4B, and 4C, the magnetization directions of both the hard and soft layers can be reversed at wire positions where the magnetic field strength (stabilizing magnetic field) is -1.0 or less (absolute value 1 or greater). Furthermore, in Figures 4A, 4B, and 4C, the magnetization direction of the soft layer can be reversed at wire positions where the magnetic field strength (operating magnetic field) is -0.5 or less (absolute value 0.5 or greater). At the wire position where the magnetic field strength is −0.5 or less and greater than −1.0 (absolute value of 0.5 or more and less than 1.0), the magnetization direction of the soft layer can be reversed, but the magnetization direction of the hard layer cannot be reversed.

[0057] In the three-dimensional magnetic simulation results of the model using the first comparative example shown in FIG. 4A, at the rotation angle where a stabilizing magnetic field (absolute value 1 or more) is applied at any wire position, the magnetic field strength is significantly different between the ends and the center of the magnetic wire 110. This indicates that the magnetic field direction near both ends of the magnetic wire 110 is not aligned with the axial direction x of the magnetic wire 110. The stabilizing magnetic field is not applied near both ends of the magnetic wire 110, specifically at wire positions 0 to 2 and 8 to 10. That is, the stabilizing magnetic field is not applied in approximately 40% of the region, and the magnetization directions of the hard layer and soft layer are mismatched in this region, leaving the remaining 60% as the matched region. Therefore, when the operating magnetic field is subsequently applied, only the reversal of the soft layer in the 60% matched region contributes to the output, resulting in a very small pulse signal.

[0058] In the results of a three-dimensional magnetic simulation of a model using the power generation sensor 300 of the second comparative example shown in Figure 4B, the difference in magnetic field strength with respect to wire position is smaller than in the first comparative example. At the rotation angle where a stabilizing magnetic field (absolute value 1 or greater) is applied at any wire position, the mismatched region of the magnetization directions of the hard and soft layers is about 20% (wire positions 0 to 1 and 9 to 10), and the matched region is the remaining 80%, which is an improvement over the first comparative example. However, when the operating magnetic field is applied thereafter, only the reversal of the soft layer in the 80% matched region contributes to the output, so the properties of the magnetic wire 110 cannot be fully utilized, and the pulse signal is small.

[0059] 4C shows that there is no substantial difference in magnetic field strength between the ends of the magnetic wire 110 and the center at any rotation angle. This indicates that the magnetic field applied to the magnetic wire 110 is parallel to the axial direction x of the magnetic wire 110 over the entire length of the magnetic wire 110 at any rotation angle. In other words, the magnetic field generated by the magnet 410 is corrected to a magnetic field parallel to the axial direction x of the magnetic wire 110 and applied to the magnetic wire 110.

[0060] In the structure of this first model, a relatively small magnetic field generating source (magnet 410) cannot generate an alternating magnetic field parallel to the axial direction x of the magnetic wire 110 in the spatial region where the power generating sensor 100 is placed. Nevertheless, according to the power generating sensor 100 of the first embodiment, the alternating magnetic field generated by the movement of the magnetic field generating source (magnet 410) is corrected to a magnetic field parallel to the axial direction x of the magnetic wire 110 and applied to the magnetic wire 110. This allows a stabilizing magnetic field to be applied over the entire length of the magnetic wire 110, eliminating regions where the magnetization directions of the hard layer and soft layer do not match. Therefore, it is possible to fully utilize the inherent properties of the magnetic wire 110, and a stable, high-output pulse signal can be output.

[0061] [Second model] 5A and 5B show a second model of a rotation detection device using a power generation sensor 300 of a second comparative example and the power generation sensor 100 of the first embodiment, respectively. The rotation detection device includes a magnet 410 that rotates around a rotation axis 411 and power generation sensors 300 and 100 that are disposed with their axial center positions 113 offset from the rotation axis 411 in a direction perpendicular to the rotation axis 411. The power generation sensors 300 and 100 are disposed with the axial direction x of the magnetic wire 110 set to follow a tangent to an imaginary circle whose central axis is the rotation axis 411. Note that the coil 120 (see FIGS. 1A and 1B) of the power generation sensors 300 and 100 is not shown in each figure. The magnetic wire 110 is disposed at a distance g from the magnet 410 in a direction parallel to the rotation axis 411 and faces the magnet 410. The magnet 410, which is the detection medium, is an example of the magnetic field generation source 400, and is a ring-shaped two-pole magnet similar to the first model.

[0062] 6A and 6B show the results of a three-dimensional magnetic simulation in the arrangement shown in FIG. 5A (a second model using the power generating sensor 300 of the second comparative example). FIG. 6C shows the results of a three-dimensional magnetic simulation in the arrangement shown in FIG. 5B (a second model using the power generating sensor 100 of the first embodiment). Similar to FIGS. 4A to 4C, FIGS. 6A to 6C are graphs showing the magnetic field applied to the magnetic wire 110 at multiple rotation angles of the magnet 410 when the magnet 410 is rotated around the rotation axis 411. The wire position on the horizontal axis and the magnetic field strength on the vertical axis are the same as those in FIGS. 4A to 4C, and therefore will not be described here.

[0063] 6A shows the results of a magnetic simulation when the air gap g (the distance between the magnet surface and the magnetic wire 110) of the power generation sensor 300 is the same as that shown in FIG. 2B (see FIG. 4B for the corresponding magnetic simulation results). According to FIG. 6A, the magnetic field strength is almost uniform across the entire area of ​​the magnetic wire 110 at all rotation angles. However, since the absolute value of the magnetic field strength is less than 1 at all rotation angles, a stabilizing magnetic field cannot be applied to the magnetic wire 110.

[0064] FIG. 6B shows the results of a magnetic simulation in the case where the air gap g of the power generating sensor 300 of the second comparative example is narrowed (brought closer to the magnet 410) to a position where a stabilizing magnetic field is applied to the magnetic wire 110 in the model of FIG. 5A. According to FIG. 6B, when the rotation angle is 0 degrees, a stabilizing magnetic field (with an absolute value of magnetic field strength of 1 or more) can be applied to the magnetic wire 110 at wire positions 2 to 8. Therefore, the magnetization directions of the hard and soft layers are aligned over approximately 60% of the entire axial length range of the magnetic wire 110 (wire positions 2 to 8). This is the set state (preparation state) before a positive signal is output. From this state, an operating magnetic field (with a magnetic field strength of +0.5 or more) that reverses the soft layer is applied to wire position "8" at a rotation angle of approximately 60 degrees in the first quadrant. However, at this rotation angle (approximately 60 degrees), a magnetic field (negative magnetic field strength) that interferes with the operating magnetic field is applied to wire positions 0 to 6, for example. Therefore, the soft layer inversion occurs at most in about 20% (in the range of 6 to 8 wire positions).

[0065] This phenomenon within the rotation angle range of the first quadrant is thought to be caused by the fact that the alternating magnetic field generated at a position opposite to the rotation trajectory of the magnet 410 contains undesirable harmonic components that interfere with the magnetic field component in the axial direction x of the magnetic wire 110.

[0066] 6C shows a three-dimensional magnetic simulation result of a model using the power generating sensor 100 of the first embodiment. It can be seen that there is no substantial difference in magnetic field strength between the ends of the magnetic wire 110 and the center at any rotation angle. This indicates that the magnetic field applied to the magnetic wire 110 is parallel to the axial direction x of the magnetic wire 110 over the entire length of the magnetic wire 110 at any rotation angle. In other words, the magnetic field generated by the magnet 410 is corrected to a magnetic field parallel to the axial direction x of the magnetic wire 110 and applied to the magnetic wire 110.

[0067] In the structure of this second model, the power generating sensors 300 and 100 are placed in a spatial region where an alternating magnetic field with superimposed undesired harmonic components is generated by the movement of the magnetic field generating source (magnet 410). Nevertheless, according to the power generating sensor 100 of the first embodiment, the alternating magnetic field caused by the movement of the magnetic field generating source (magnet 410) is corrected in the axial direction x of the magnetic wire 110 and applied over the entire length of the magnetic wire 110. As a result, there is essentially no mismatch region where the magnetization directions of the hard layer and the soft layer differ. Therefore, it is possible to fully utilize the inherent properties of the magnetic wire 110, and a stable, high-output pulse signal can be output.

[0068] This second model has the advantage that the power generation sensor 100 can be offset from the axis of rotation 411 to form a through-shaft type device.

[0069] Patent Document 3 provides a technique for suppressing the strength of a magnetic field that is not parallel to the axial direction x of a magnetic wire by using a magnet with regions of different magnetic field strength. This technique contributes to improving the magnetic field strength as shown in Figure 3 or Figure 5 of Patent Document 3, but this requires improvement of the magnet, which is the detection medium. In contrast, the power generation sensor 100 of the first embodiment does not necessarily require improvement of the magnet, and can solve the problems with the configuration of Patent Document 3.

[0070] [Third model] 7A and 7B show a third model of a rotation detection device using the power generating sensor 100 of the first embodiment. The second model shown in FIG. 5B uses a two-pole magnet 410 as a magnetic field generation source, and the power generating sensor 100 of the first embodiment is positioned offset from the rotation axis 411 of the magnet 410. In contrast, the third model shown in FIGS. 7A and 7B is a rotation detection device in which the magnetic field generation source has multiple poles. Below, we will explain that rotation detection using a multi-pole magnet is possible based on the results of a magnetic simulation showing the magnetic field strength applied to the magnetic wire 110 when the multi-pole magnet of the magnetic field generation source rotates.

[0071] The magnetic field source is a magnet that has four magnetic poles, i.e., two north poles and two south poles, passing through the detection region 140 of the power generating sensor 100. Specifically, in the configuration of FIG. 7A , the magnetic field source is a ring-shaped magnet 420 having four magnetic pole regions, with north and south pole regions alternately arranged circumferentially on the surface facing the power generating sensor 100. The ring-shaped magnet 420 rotates around a rotation axis 421 that coincides with its central axis, thereby generating an alternating magnetic field in the detection region 140 of the power generating sensor 100. In the configuration of FIG. 7B , the magnetic field source is composed of four individual magnets 430. The four magnets 430 are arranged along a circumference centered on the rotation axis 431. For example, the magnets 430 are permanent magnets of the same shape and size that are equally spaced circumferentially around the rotation axis 431. The four magnets 430 rotate around the rotation axis 431 while maintaining their relative positions around the rotation axis 431. Each magnet 430 is arranged with its magnetization direction set parallel to the rotation axis 431. The four magnets 430 are arranged so that the north and south poles are alternately aligned along the rotation direction on the side facing the power generation sensor 100. Therefore, when the four magnets 430 rotate around the rotation axis 431, the north and south poles alternately face the power generation sensor 100, thereby forming an alternating magnetic field in the detection region 140 of the power generation sensor 100.

[0072] In the ring-shaped magnet 420 shown in Figure 7A, the circumferential length (α) of one magnetic pole region is equal to the magnetic pole pitch λ, which is the distance from the circumferential center of the north pole region to the circumferential center of the south pole region. In the individual magnets shown in Figure 7B, the circumferential length (α) of one magnetic pole is shorter than the magnetic pole pitch λ, which is the circumferential distance between the circumferential centers of adjacent magnets.

[0073] The power generating sensor 100 is disposed such that the magnetic wire 110 is offset in the direction of the rotation radius from the rotation axes 421, 431 of the magnets 420, 430. That is, the magnetic wire 110 is offset to a position facing the rotation trajectory of the magnets 420, 430 along a direction parallel to the rotation axes 421, 431 (orthogonal direction z). The power generating sensor 100 is disposed such that the axial direction x of the magnetic wire 110 is set along a tangent to an imaginary circle whose central axis is the rotation axes 421, 431, and the detection region 140 (see FIG. 1B) is set on the side of the magnets 420, 430. In both the configurations of FIGS. 7A and 7B, the magnetic pole pitch λ is set to be equal to or less than the distance D between the axis-orthogonal portions 133 of the magnetic flux conducting pieces 130, 131.

[0074] Figure 8 shows the results of a three-dimensional magnetic simulation for the arrangement shown in Figure 7B. Figure 8 is a graph showing the magnetic field applied to the magnetic wire 110 at multiple rotation angles when four magnets 430 are rotated around the rotation axis 431. The wire position on the horizontal axis and the magnetic field strength on the vertical axis are the same as in Figures 4A to 4C, so their explanation will be omitted. The rotation angle is defined as 0 degrees for the state shown in Figure 7B, and 90 degrees for the state rotated by the magnetic pole pitch λ.

[0075] 8, it can be seen that there is substantially no difference in magnetic field strength between the vicinity of both ends and the center of the magnetic wire 110 at any rotation angle. This indicates that the magnetic field applied to the magnetic wire 110 is parallel to the axial direction x of the magnetic wire 110 over the entire length of the magnetic wire 110 at any rotation angle. In other words, this indicates that the magnetic field generated by the magnet 430 is corrected to a magnetic field parallel to the axial direction x of the magnetic wire 110 and applied to the magnetic wire 110.

[0076] 8 also shows that a negative stabilizing magnetic field (a magnetic field with an intensity of -1 or less (absolute value 1 or more)), a positive stabilizing magnetic field (a magnetic field with an intensity of +1 or more), a negative operating magnetic field (a magnetic field with an intensity of -0.5 or less (absolute value 0.5 or more)), and a positive operating magnetic field (a magnetic field with an intensity of +0.5 or more) are applied during the rotational movement in which the rotation angle changes from 0 to 90 degrees. In other words, during the rotational movement in which the rotation angle changes from 0 to 90 degrees, the following states are achieved: a set state (preparatory state) in which the magnetization directions of the hard layer and soft layer match before the output of a positive signal; a state in which an operating magnetic field is applied from that set state to reverse only the soft layer and output a positive signal; a set state (preparatory state) in which the magnetization directions of the hard layer and soft layer match before the output of a negative signal; and a state in which an operating magnetic field is applied from that set state to reverse only the soft layer and output a negative signal. Therefore, it can be seen that two positive signal pulses and two negative signal pulses are output, for a total of four pulses, while the four magnets 430 make one rotation (360-degree rotation) around the rotation axis 431. Although not shown, the results of a three-dimensional magnetic simulation for the arrangement shown in Fig. 7A were substantially similar to those in Fig. 8.

[0077] In this way, even in the third model, which uses multi-pole magnets 420, 430 as the magnetic field generating source and has a shorter magnetic pole pitch than the second model, the alternating magnetic field formed in the detection area 140 by its movement is corrected to a magnetic field in the axial direction x of the magnetic wire 110.

[0078] Even when configuring a rotation detection device that is a through-shaft type and can output multiple pulse signals within one rotation, as in the third model, the configuration can be simplified by using the power generation sensor 100 of the first embodiment. That is, unlike Patent Documents 4 and 5, there is no need to specially design and prepare magnetic materials with shapes and arrangements that correspond to the configuration of the rotation detection device.

[0079] Next, we will explain the relationship between the distance D in the axial direction x between the two magnetic flux conduction pieces 130, 131 at the position of the magnetic wire 110 and the spacing (distance L) at which the two magnetic flux conduction pieces 130, 131 face each other at a position offset from the magnetic wire 110 toward the detection area 140. Specifically, the distance D is the distance in the axial direction x between the opposing inner surfaces 130b, 131b of the pair of axis-orthogonal portions 133. Specifically, the distance L is the distance in the axial direction x between the proximal ends 134a of the pair of axis-parallel portions 134. Since the magnetic flux conduction pieces 130, 131 have shapes symmetrical to each other with respect to a plane of symmetry 115 that passes through the axial center position 113 of the magnetic wire 110, the pair of proximal ends 134a face each other across the axial center position 113 when viewed from the detection area 140 (see FIG. 1B ).

[0080] Below, the results of an experiment on the ratio of the interval L between the adjacent ends 134a of the axis-parallel portions 134 to the distance D between the axis-orthogonal portions 133 will be described.

[0081] For the structures of the first model (see FIG. 2C) and the third model (see FIG. 7B) using the power-generating sensor 100 of the first embodiment, the relationship between the ratio of the distance L between the proximal ends 134a to the distance D between the magnetic flux conducting pieces 130 and 131 at the position of the magnetic wire 110 and the pulse height of the pulse signal output from the coil 120 was confirmed. The results are shown in FIG. 9. The horizontal axis of FIG. 9 represents the ratio (%) of the distance L to the distance (D), and the vertical axis represents the output pulse height. The output pulse height is normalized with its maximum value set to 1. The pulse signal pulse height is the average of the absolute values ​​of the pulse heights of the two positive and negative pulses output when the magnets 410 and 430 are rotated in the forward direction and the absolute values ​​of the pulse heights of the two positive and negative pulses output when they are rotated in the reverse direction.

[0082] From Figure 9, it can be seen that in the first model, the ratio at which 100% of the large Barkhausen effect of the properties of the magnetic wire 110 can be induced is approximately 15% to 50%, and in the third model, the ratio is approximately 20% to 45%.

[0083] In both the first and third models, at a ratio of approximately 5%, the large Barkhausen effect is reduced by several percent due to the nature of the magnetic wire 110. This is presumably due to the influence of a magnetic path formed through the narrow gap between the adjacent ends 134a of the axially parallel portions 134 (the distance L is small).

[0084] In both the first and third models, when the ratio is approximately 50% or more, the large Barkhausen effect is lower than that of the magnetic wire 110. This is presumably due to a reduction in the area of ​​the soft magnetic material parts facing the magnets 410, 430. In other words, the area of ​​the axially parallel parts 134 of the magnetic flux conduction pieces 130, 131 that covers the magnetic wire 110 from the magnets 410, 430 is small, which is presumably affecting the reduction in the aforementioned shielding effect.

[0085] The output pulse height of 0.85 at a ratio of 100% in the first model corresponds to a slightly higher output than the 3D magnetic simulation result of FIG. 4B (corresponding to the configuration of FIG. 2B), where the magnetization direction coincides with the magnetization direction of the hard layer and the soft layer by 80%. The output pulse height of 0.35 at a ratio of 100% in the third model corresponds to a slightly higher output than the 3D magnetic simulation result of FIG. 6B (corresponding to the configuration of FIG. 5A), where the magnetization direction coincides with the magnetization direction of the hard layer and the soft layer by 20%, although the magnetic pole pitch is different. Therefore, it can be seen that the surface facing the magnetic field source (detection area facing surface 134b) is better if it is flat (see the configuration of the power generation sensor 100 of the first embodiment) than if it is cylindrically curved (see the configuration of the comparative example in FIG. 2B and FIG. 5A).

[0086] If the ratio is in the range of 5% to 50%, it is possible to induce the large Barkhausen effect of 90% or more of the characteristics of the magnetic wire 110. Furthermore, if the ratio is in the range of 20% to 40%, it is possible to induce 100% of the large Barkhausen effect of the characteristics of the magnetic wire 110.

[0087] As described above, the magnetic flux conduction pieces 130, 131 made of soft magnetic parts have the function of correcting the alternating magnetic field formed in the detection area 140 by the magnetic field source in the axial direction x of the magnetic wire 110 and applying it to the magnetic wire 110. This increases the output of the signal induced in the coil 120 wound around the magnetic wire 110. The power generating sensor 100, which is integrally equipped with the magnetic flux conduction pieces 130, 131 having such a magnetic field correction function, can be used with a variety of detection media.

[0088] Furthermore, by setting the ratio of the distance L between the opposing near ends 134a of the pair of magnetic flux conduction pieces 130, 131 offset from the magnetic wire 110 toward the detection area 140 to the distance D at the position of the magnetic wire 110 within the aforementioned range, the magnetic flux conduction pieces 130, 131 can exhibit the excellent magnetic field correction function described above. Even if the axial lengths of the magnetic wires 110 are different, it is sufficient to design them so that the ratio range is observed, so the shape of the magnetic flux conduction pieces 130, 131 can be easily designed.

[0089] As shown in FIGS. 1A and 1B , the first end 111 and the second end 112 of the magnetic wire 110 are exposed from the magnetic flux conduction pieces 130, 131 made of soft magnetic material. However, the first end 111 and the second end 112 do not have to be exposed from the magnetic flux conduction pieces 130, 131. Furthermore, if they are exposed, the first end 111 and the second end 112 may or may not protrude from the magnetic flux conduction pieces 130, 131 in the axial direction x. If they protrude, the protrusion length is not limited. The diameter or width of the hole or groove constituting the wire placement section 130a, 131a formed by penetrating the magnetic flux conduction pieces 130, 131 made of soft magnetic material in the axial direction x is preferably equal to or larger than the hole diameter or groove width that allows the magnetic wire 110 to slide (slide) so as not to apply stress to the magnetic wire 110 used. Specifically, the diameter or width may be set to be larger than the diameter of the magnetic wire 110, within a few percent of the diameter of the magnetic wire 110.

[0090] The wire arrangement portions 130a and 131a are preferably arranged at positions offset in a direction away from the detection region 140, that is, on the side not facing the magnetic field generation source when viewing the magnetic flux conduction pieces 130 and 131 in the axial direction x. That is, as shown in FIG. 1A, the distance h from the magnetic wire 110 to one end of the axially orthogonal portion 133 (the end opposite to the detection region 140) and the distance H from the magnetic wire 110 to the detection region facing surface 134b of the magnetic flux conduction pieces 130 and 131 preferably satisfy the relationship h < H. More preferably, by making the distance h substantially equal to the radius of the coil 120, the length h + H of the magnetic flux conduction pieces 130 and 131 in the orthogonal direction z becomes shorter, and the size of the power generation sensor 100 in the orthogonal direction z can be reduced. Further, if the width t of the magnetic flux conduction pieces 130 and 131 when viewed in the axial direction x is made substantially equal to the diameter of the coil 120, the size of the power generation sensor 100 in the width direction y can be reduced. Thus, the power generation sensor 100 can be made small.

[0091] The soft magnetic component constituting the magnetic flux conduction pieces 130 and 131 is preferably made of a magnetic material having a coercive force not exceeding that of the magnetic wire 110 and a high magnetic permeability (for example, 500 or more). Specifically, a material containing Ni-based ferrite or Mn-based ferrite is preferable. These materials have excellent characteristics such as low hysteresis, low self-capacitance, and low iron loss. Therefore, when a high-frequency alternating magnetic field generated when the magnetic field generation source moves at high speed is applied to the power generation sensor 100, there is an advantage that the output characteristics are not affected.

[0092] Furthermore, if the width of the hole formed through the magnetic flux conduction pieces 130 and 131, that is, the thickness W of the axially orthogonal portion 133 (see FIG. 1A), is too large, the arrangement width of the coil 120 becomes narrow, so the efficiency of picking up the large Barkhausen effect of the magnetic wire 110 decreases. If it is too small, the magnetic path becomes narrow. Therefore, based on experimental findings, the thickness W is preferably 10% to 20% of the total length of the magnetic wire 110.

[0093] [Modification of the First Embodiment] Although the magnetic flux conduction pieces 130, 131 made of soft magnetic material parts in the first embodiment are one-piece L-shaped pieces, as shown in Fig. 10, the magnetic flux conduction pieces 130, 131 may be configured by combining two rectangular parallelepiped portions 130-1, 130-2; 131-1, 131-2 that respectively constitute the axis-orthogonal portion 133 and the axis-parallel portion 134. In this case, it is preferable to arrange and combine the two rectangular parallelepiped portions 130-1, 130-2; 131-1, 131-2 to form an L shape. However, the two rectangular parallelepiped portions 130-1, 130-2; 131-1, 131-2 do not need to form a complete L-shape, and may be arranged, for example, in a T-shape (in which the end faces of the rectangular parallelepiped portions 130-1, 131-1 forming the axis-orthogonal portion abut against each other at the intermediate portion in the axial direction x of the rectangular parallelepiped portions 130-2, 131-2 forming the axis-parallel portion 134). The two rectangular parallelepiped portions 130-1, 130-2; 131-1, 131-2 forming each magnetic flux conduction piece 130, 131 may be made of the same soft magnetic material or different soft magnetic materials, and are preferably made of materials selected from the above-mentioned range of materials.

[0094] [Second embodiment] The magnetic flux conducting pieces 130, 131 of the power generation sensor 100 of the first embodiment have flat surfaces facing the magnetic field source (facing the detection area 140), and therefore, these flat surfaces can be used as surface mounting areas.

[0095] 11A, 11B, and 11C are a perspective view, a partially exploded perspective view, and a side view, respectively, for explaining the configuration of a power generation sensor 200 according to a second embodiment. In the explanation of the second embodiment, the same reference numerals as in the first embodiment are used for components corresponding to those in the first embodiment.

[0096] In the power generation sensor 200 of the second embodiment, external terminal electrodes 240, 241 that can be surface mounted are provided directly on magnetic flux conducting pieces 130, 131 made of soft magnetic material parts.

[0097] Specifically, the external terminal electrodes 240, 241 are provided on the surfaces of the magnetic flux conduction pieces 130, 131 that face the magnetic field source. More specifically, the external terminal electrodes 240, 241 are provided on the detection-region-facing surface 134b of the axis-parallel portion 134, i.e., on the surface of the axis-parallel portion 134 opposite the magnetic wire 110. The external terminal electrodes 240, 241 are made of, for example, a plating layer or a conductive paste and a solder layer. In this embodiment, the external terminal electrodes 240, 241 are provided so as to cover the entire detection-region-facing surface 134b of the axis-parallel portion 134. However, the external terminal electrodes 240, 241 may be provided so as to cover only a portion of the detection-region-facing surface 134b of the axis-parallel portion 134.

[0098] The power-generating sensor 200 of this embodiment further includes a case 210 that houses the magnetic wire 110, the coil 120, and the magnetic flux conduction pieces 130, 131. The case 210 is formed in a box shape that opens toward the detection-area facing surfaces 134b of the magnetic flux conduction pieces 130, 131, and is configured to house the magnetic wire 110, the coil 120, and the magnetic flux conduction pieces 130, 131 with the detection-area facing surfaces 134b of the magnetic flux conduction pieces 130, 131 exposed. As described above, the magnetic wire 110 is fixed to the magnetic flux conduction pieces 130, 131. Specifically, both end portions 111, 112 of the magnetic wire 110 are fixed with resin to wire placement portions 130a, 131a, which are holes or grooves formed through the axis-orthogonal portions 133 of the magnetic flux conduction pieces 130, 131. The magnetic flux conducting pieces 130, 131 and the coil 120 are fixed to the case 210 by, for example, adhesive resin and / or fitting. This results in the power generation sensor 200 being integrated and complete in configuration, including the case 210.

[0099] FIG. 11B is a partially exploded perspective view showing a state before the case 210 is fitted, and FIG. 11C is a side view of the magnetic flux conduction piece 130 in the axial direction x with the case 210 removed. In this embodiment, the axis-orthogonal portion 133, which is substantially rectangular parallelepiped-shaped, has protrusions 130x, 130y, 131x, and 131y on both sides of the width direction y, protruding in a width direction y that is perpendicular to the axial direction x and parallel to the detection region-facing surface 134b. In the illustrated example, these protrusions 130x, 130y, 131x, and 131y are arranged on the opposite side of the magnetic wire 110 from the detection region-facing surface 134b. The axis-orthogonal portion 133 has chamfered portions 133a (e.g., rounded chamfered portions) at both corners in the width direction y on the end surface opposite the detection region-facing surface 134b. The chamfered portions 133a function as guides to facilitate smooth insertion of the case 210.

[0100] The case 210 has holes 220x, 220y, 221x, and 221y at corresponding positions into which the protrusions 130x, 130y, 131x, and 131y of the magnetic flux conduction pieces 130 and 131 fit, respectively. Grooves 230 and 231 are also formed in the case 210 so that both ends of the magnetic wire 110 do not come into contact with each other when the case 210 is assembled into the case 210. The grooves 230 and 231 extend in a direction z perpendicular to the detection area facing surface 134b, and the case 210 is assembled so that both ends of the magnetic wire 110 are inserted into the grooves 230 and 231 from this direction z.

[0101] As best seen in FIG. 11C , a side view seen from the axial direction x, grooves 130c and 131c through which the wire lead 120a passes to make electrical contact with the coil 120 are provided on the detection-area-facing surface 134b of the magnetic flux conduction piece 130. The wire lead 120a is connected to the external terminal electrodes 240 and 241 in the grooves 130c and 131c by a solder layer. For example, in the manufacturing process, it is preferable to form the external terminal electrodes 240 and 241 on the detection-area-facing surface 134b after placing the wire lead 120a in the grooves 130c and 131c. As shown in FIG. 11B , the grooves 130c and 131c may also be continuous with the proximal end 134a of the axial-parallel portion 134.

[0102] 12A and 12B are front views of the magnetic flux conduction piece 130 as viewed from the width direction y, which is perpendicular to the axial direction x and parallel to the detection-area-facing surface 134b. FIG. 12A shows an example in which the thickness W of the axis-orthogonal portion 133 in the axial direction x is uniform. That is, the thickness W of the axis-orthogonal portion 133 in the axial direction x is substantially equal on the detection-area-facing surface side and the opposite side, and the thickness W is also constant in the region between them. Therefore, the axis-orthogonal portion 133 has a linear straight shape along the orthogonal direction z. On the other hand, FIG. 12B shows an example in which the thickness W of the axis-orthogonal portion 133 in the axial direction x is not uniform. That is, in this example, the thickness W of the axis-orthogonal portion 133 in the axial direction x is smaller on the detection-area-facing surface 134b side and larger on the opposite side, with the thickness W varying linearly in the region between them. Therefore, the axis-orthogonal portion 133 has a tapered shape in the orthogonal direction z in front view, tapering toward the detection-area-facing surface 134b. That is, the axis-orthogonal portion 133 has two non-parallel planes that intersect with the axial direction x. The axis-orthogonal portion 133 having such a tapered shape has a function of preventing the case 210 from coming off.

[0103] 12C is a perspective view showing the configuration of a modified example of the magnetic flux conduction piece 131. The axially parallel portion 134 of the magnetic flux conduction piece 131 has a surface 131z curved along the cylindrical outer periphery of the coil 120 on the surface facing the cylindrical coil 120 (the surface opposite the detection area-facing surface 134b). The surface 131z may be a cylindrical surface or an elliptical cylindrical surface that matches the cylindrical shape of the coil 120. This configuration enables the magnetic flux conduction piece 131 to position and / or hold the coil 120, thereby improving the stability of holding the coil 120.

[0104] Providing the above-described protrusions, inclined surfaces, or curved surfaces on the magnetic flux conduction pieces 130, 131 does not impair the function of the magnetic flux conduction pieces 130, 131 to correct the alternating magnetic field formed in the detection area 140 in the axial direction x of the magnetic wire 110. In other words, the axis-orthogonal portion 133 and the axis-parallel portion 134 do not need to be strictly rectangular parallelepiped in shape, and it is sufficient if they have a substantially rectangular parallelepiped shape as long as the magnetic field correction function of the magnetic flux conduction pieces 130, 131 is not impaired. Although it is preferable that the axis-orthogonal portion 133 and the axis-parallel portion 134 be configured in a substantially rectangular parallelepiped shape, they may also be configured in another shape as long as the above-described magnetic field correction function is obtained.

[0105] [Modification of the second embodiment] 13A and 13B are diagrams illustrating the configuration of a modified example of the power generating sensor 200 according to the second embodiment. In this modified example, the external terminal electrodes are formed of lead frames. FIG. 13A is a perspective view of the lead frame-type power generating sensor 200 before the case 210 is fitted. The case structure is the same as that shown in FIGS. 11A and 11B. FIG. 13B is an assembly diagram of the lead frames 250 and 251 before they are attached to the magnetic flux conduction pieces 130 and 131. However, in FIG. 13B, the magnetic wire 110 and the coil 120 are not shown. The same reference numerals are used to designate corresponding parts shown in FIGS. 11A to 11C.

[0106] The lead frames 250, 251 are formed to fit the shapes of the magnetic flux conduction pieces 130, 131. More specifically, the lead frames 250, 251 are configured to be substantially symmetrical with respect to a symmetry plane 115 perpendicular to the axial direction x at the axial center position 113 of the magnetic wire 110. The lead frames 250, 251 include a side portion 252 perpendicular to the axial direction x along the outer side surface of the magnetic flux conduction piece 130, 131, a top surface portion 253 extending inward in the axial direction x from one edge of the side portion 252 along the top surface of the axis-orthogonal portion 133 (the surface opposite to the axis-parallel portion 134), and a bottom surface portion 254 extending inward in the axial direction x from another edge of the side portion 252 along the detection area facing surface 134b, and are configured to have an inwardly opening C-shape (sideways U-shape) when viewed from the front. The magnetic flux conduction pieces 130, 131 are formed with recesses 136a, 136b, 136c for accommodating the lead frames 250, 251. Specifically, the recess 136a for accommodating the side surface portion 252 is formed on the outer surface of the axis-orthogonal portion 133, the recess 136b for accommodating the top surface portion 253 is formed on the top surface of the axis-orthogonal portion 133, and the recess 136c for accommodating the bottom surface portion 254 is formed on the detection-area-opposing surface 134b. As a result, the lead frames 250, 251 are arranged so as to contact the magnetic flux conduction pieces 130, 131 at the bottom surfaces of the recesses 136a, 136b, 136c. The bottom surface 254 of the lead frames 250, 251 is accommodated in the recess 136c and is flush with the detection area facing surface 134b of the magnetic flux conducting pieces 130, 131, forming a flat surface that can be surface mounted on the side facing the magnetic field source, i.e., the detection area 140 (see Figure 1B) side.

[0107] Holes 250a, 251a through which the magnetic wire 110 passes are formed in the side surface portions 252 of the lead frames 250, 251. Protrusions 250c, 250d, 251c, 251d that protrude inward toward the magnetic flux conduction pieces 130, 131 are formed in the top surface portion 253 and bottom surface portion 254 of the lead frames 250, 251. These protrusions 250c, 250d, 251c, 251d may be formed, for example, by convex punch marks. Grooves 130d, 131d are formed in the top surface portion of the axis-orthogonal portion 133 along the axial direction x at positions corresponding to the protrusions 250c, 251c. The protrusions 250d, 251d are also provided in positions corresponding to the grooves 130c, 131c formed in the detection-area facing surface 134b. The protrusions 250c, 250d, 251c, and 251d fit into the corresponding grooves 130d, 130c, 131d, and 131c, respectively, facilitating the relative positioning of the lead frames 250, 251 and the magnetic flux conduction pieces 130, 131 and contributing to improved ease of attachment when attaching the lead frames 250, 251 to the magnetic flux conduction pieces 130, 131. The top surfaces 253 of the lead frames 250, 251 are provided with protrusions 250b and 251b for entangling and connecting the coil terminal wire 120a. This electrically connects the coil terminal wire 120a to the lead frames 250, 251, and the power generation sensor 200 can be surface-mounted by joining the bottom surfaces 254 of the lead frames 250, 251 to a printed circuit board or the like.

[0108] In this way, by forming the external terminal electrodes using lead frames 250, 251 that directly contact magnetic flux conducting pieces 130, 131, the number of components that make up power generating sensor 200 is reduced, and a power generating sensor 200 that is simple in structure, small in size, and can be surface-mounted can be provided.

[0109] [Example of a rotation detection device using the power generation sensor of the second embodiment] 14A and 14B show a first configuration example of a rotation detection device using a power-generating sensor 200 according to the second embodiment. FIG. 14A is a perspective view, and FIG. 14B is a plan view. This rotation detection device includes a ring magnet 440 as a magnetic field generating source and the power-generating sensor 200. The ring magnet 440 is coupled to the rotation axis 441 so that the rotation axis 441 passes through its center and rotates together with the rotation axis 441 around the axis. The ring magnet 440 is a six-pole magnet with three north poles and three south poles arranged alternately in the circumferential direction on a magnetic pole face perpendicular to the rotation axis 441. A substrate 500 is disposed facing the magnetic pole face of the ring magnet 440, and the power-generating sensor 200 is disposed on the substrate 500. The power-generating sensor 200 is surface-mounted on the substrate 500, with the detection-area-facing surfaces 134b of the magnetic flux conduction pieces 130, 131 facing the magnetic pole face of the ring magnet 440. More specifically, the power generation sensor 200 is disposed so that the magnetic wire 110 is parallel to a tangent 443 on a circumference 442 corresponding to the rotation locus of the ring magnet 440 and faces the tangent 443 in the axial direction of the rotation shaft 441. In other words, the power generation sensor 200 is disposed offset from the rotation shaft 441 in the direction of the rotation radius, thereby forming a rotation detection device that penetrates the rotation shaft. The power generation sensor 200 outputs six pulses per rotation of the rotation shaft 441.

[0110] 15A and 15B show a second configuration example of a rotation detection device using a power generation sensor 200 according to the second embodiment; FIG. 15A is a perspective view, and FIG. 15B is a plan view. In this configuration example, the power generation sensor 200 is mounted on a substrate 500 with its center aligned with the center of a rotating shaft 441. This configuration is possible because the six-pole ring magnet 440, with its south and north poles alternately arranged in the circumferential direction, faces the opposite poles of one of the pair of magnetic flux conduction pieces 130, 131. While this configuration example does not have a through-rotating-shaft configuration, it has the advantage of making the device itself more compact.

[0111] 16A and 16B show a third example of the configuration of a rotation detection device using the power generating sensor 200 according to the second embodiment, with FIG. 16A being a perspective view and FIG. 16B being a plan view. In this example, the power generating sensor 200 (more specifically, the magnetic wire 110) is positioned at a position intersecting the axis of the rotation shaft 441, but the center of the power generating sensor 200 (more specifically, the center of the magnetic wire 110) is offset in the direction of the radius of rotation relative to the rotation shaft 441. In this configuration, a part of one of the magnetic flux conducting pieces 130 Gari The other magnetic flux conducting piece 131 faces the rotation locus of the pole face of the ring magnet 440, while the other magnetic flux conducting piece 131 does not face the rotation locus of the pole face of the ring magnet 440. Even with this arrangement, there is no substantial effect on the pulse signal output from the power generation sensor 200, and a pulse signal substantially similar to that of the second configuration example is obtained.

[0112] These first to third configuration examples are made possible by the magnetic flux conduction pieces 130, 131 having a magnetic field correction function that corrects the alternating magnetic field formed in the detection area 140 in the axial direction x of the magnetic wire 110 and applies it to the magnetic wire 110. In particular, by appropriately determining the ratio of the distance L between the proximal ends 134a of the magnetic flux conduction pieces 130, 131 to the distance D between the pair of magnetic flux conduction pieces 130, 131 at the position of the magnetic wire 110, there is an advantage that the degree of freedom in the arrangement of the power generating sensor 200 is increased while still not significantly affecting the output pulse signal. This allows for various arrangements of the power generating sensor, including the arrangements exemplified in the first to third configuration examples. Therefore, it is possible to provide a power generating sensor 200 that can be easily incorporated into rotation detection devices of various configurations and can obtain stable output.

[0113] Although one embodiment of the present invention has been described, the present invention can be embodied in other forms.

[0114] For example, in the above-described embodiment, the pair of magnetic flux conducting pieces 130, 131 are configured symmetrically with respect to the symmetry plane 115 set at the axial center position 113 of the magnetic wire 110, but in this case, "symmetry" allows for differences within a range that does not affect the magnetic field correction function of the magnetic flux conducting pieces 130, 131, and does not require strict geometric symmetry.

[0115] Furthermore, in the above description, an example was shown in which the power generation sensor is used to detect rotational position, but the power generation sensor may also be applied to a position detection device that detects linear motion.

[0116] In addition, various design modifications can be made within the scope of the claims. [Explanation of symbols]

[0117] 100: Power generation sensor 110: Magnetic wire 111: First end 112: Second end 113: Axis center position 120: Coil 130: Magnetic flux conducting piece 130a: Wire placement section 131: Magnetic flux conducting piece 131a: Wire placement section 133: Axis perpendicular part 134: Axis parallel part 134a: Near end 134b: detection area facing surface 140: Detection area 200: Power generation sensor 240: External terminal electrode 241: External terminal electrode 250: Lead frame 251: Lead frame 400: Magnetic field source 410: Magnet 420: Magnet 430: Magnet 440: Ring magnet D: Distance L: distance W: Thickness x: Axial direction y: Width direction z: Orthogonal direction

Claims

1. a magnetic wire that exhibits the large Barkhausen effect when an alternating magnetic field is applied in the axial direction; a coil wound around the magnetic wire; a pair of magnetic flux conducting pieces each consisting of a pair of soft magnetic parts magnetically coupled to both ends of the magnetic wire, the pair of magnetic flux conducting pieces being symmetrical with respect to a symmetry plane set at a center position of the magnetic wire in the axial direction, The pair of magnetic flux conduction pieces include a pair of axis-orthogonal portions to which both ends of the magnetic wire are respectively fixed, extending parallel to each other in a direction orthogonal to the axial direction from both ends of the magnetic wire, and a pair of axis-parallel portions that extend from tip ends of the axis-orthogonal portions in directions approaching each other along the axial direction, with proximal ends facing each other with a gap in the axial direction, the axial distance of the interval is 5% to 50% of the axial distance between the pair of axis-orthogonal portions at the coupling position with the magnetic wire, a detection area on the side opposite to the magnetic wire with respect to the axially parallel portion; the axis-orthogonal portion of the magnetic flux conducting piece has a wire placement portion having a hole or groove formed therein that penetrates in the axial direction, The magnetic wire passes through the axis-orthogonal portion in the wire placement portion and is fixed to the axis-orthogonal portion.

2. The power generating sensor of claim 1, wherein the pair of magnetic flux conducting pieces are configured to correct the magnetic field formed in a space including the pair of magnetic flux conducting pieces by a magnetic field generating source arranged in the detection area into an axial magnetic field and apply it to the magnetic wire.

3. 3. The power generating sensor according to claim 1, wherein the axial distance of the gap is 20% to 40% of the axial distance between the pair of axis-orthogonal portions at the position where the magnetic wire is connected.

4. 4. The power generation sensor according to claim 1, wherein the thickness of the axis-orthogonal portion in the axial direction at the position where the magnetic wire is joined is 10% to 20% of the total length of the magnetic wire.

5. 5. The power generation sensor according to claim 1, wherein the soft magnetic part is made of a material having a coercive force equal to or less than that of the magnetic wire and a magnetic permeability of 500 or more.

6. 6. The power generation sensor according to claim 1, further comprising an external terminal electrode for surface mounting provided on the axially parallel portion of the magnetic flux conducting piece so as to face the detection area.

7. A magnetic wire that exhibits the large Barkhausen effect when an alternating magnetic field is applied axially; a coil wound around the magnetic wire; a pair of magnetic flux conducting pieces each consisting of a pair of soft magnetic parts magnetically coupled to both ends of the magnetic wire, the pair of magnetic flux conducting pieces being symmetrical with respect to a symmetry plane set at a center position of the magnetic wire in the axial direction, The pair of magnetic flux conduction pieces include a pair of axis-orthogonal portions to which both ends of the magnetic wire are respectively fixed, extending parallel to each other in a direction orthogonal to the axial direction from both ends of the magnetic wire, and a pair of axis-parallel portions that extend from tip ends of the axis-orthogonal portions in directions approaching each other along the axial direction, with proximal ends facing each other with a gap in the axial direction, the axial distance of the interval is 5% to 50% of the axial distance between the pair of axis-orthogonal portions at the coupling position with the magnetic wire, a detection area on the side opposite to the magnetic wire with respect to the axially parallel portion; The power generation sensor further includes an external terminal electrode for surface mounting provided on the axially parallel portion of the magnetic flux conducting piece so as to face the detection area.

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