Power generation element, and magnetic sensor and encoder using same

Abstract

Provided is a power generation element (100) comprising: a magnetic body (1) that generates a large Barkhausen effect; a power generation coil (2) in which magnetic flux passing through the magnetic body interlinks; and two soft magnetic bodies (3) that are provided at both ends of the magnetic body (1) and have an insertion section through which the magnetic body (1) is inserted, wherein a plate-like member (351) that blocks a magnetic field to the central part of the magnetic body (1) generated from a magnetic field generation source (4) is disposed between the magnetic body (1) and the magnetic field generation source (4), said plate-like member (351) is also disposed between the two soft magnetic bodies (3), a large Barkhausen effect is generated only in the vicinity of the center of the magnetic body (1), and the deterioration of power generation characteristics is thereby suppressed.

Description

Power generating element, magnetic sensor and encoder using the same

[0001] The present disclosure relates to a power generating element, and a magnetic sensor and an encoder using the same.

[0002] The Large Barkhausen effect is a phenomenon in which the direction of magnetization suddenly reverses in response to changes in an external magnetic field. By placing a power generating coil made of conductive wire around a magnetic material that exhibits this effect and applying an external magnetic field to reverse the direction of magnetization due to the Large Barkhausen effect, a power generating element can be obtained in which an electromotive force is generated in the power generating coil by electromagnetic induction.

[0003] By placing soft magnetic materials at both ends of the magnetic material that constitutes this power generating element, the demagnetizing field generated at the ends of the magnetic material is reduced, and the uniformity of the magnetic flux generated in the magnetic material can be improved. As a result, a stable large Barkhausen effect can be generated regardless of the strength and polarity of the externally applied magnetic field, and power generation characteristics with little fluctuation can be obtained (see, for example, Patent Document 1).

[0004] Japanese Patent Application Laid-Open No. 2006-73974

[0005] In the above-mentioned technology, when a power generating element is placed in the magnetic field of a rotating magnet with two or more poles, for example, if the magnetic body is long in the longitudinal direction, there is a possibility that the magnetic field of the magnet will be applied only near the center of the magnetic body of the power generating element. In this case, the large Barkhausen effect will only occur near the center of the magnetic body, making it difficult for it to occur simultaneously throughout the entire body, resulting in a problem of reduced power generating characteristics.

[0006] In addition, the magnetic field generated by the large Barkhausen effect in a magnetic material returns to the magnetic material through air, which is difficult for magnetic fields to pass through, resulting in a small change in the magnetic field and a small generated voltage due to electromagnetic induction.

[0007] The present disclosure has been made to solve the above-mentioned problems, and aims to obtain a power generating element with improved power generation characteristics that can stably output a larger generated voltage.

[0008] The power generation element disclosed herein comprises a magnetic body made of a magnetic material that generates the Greater Barkhausen Effect, a power generation coil in which magnetic flux passing through the magnetic body intersects, and two soft magnetic bodies having an insertion portion through which the magnetic body is inserted and including a soft magnetic material provided at both ends of the magnetic body so that the magnetic body comes into contact with the magnetic body when inserted into the insertion portion, and is characterized in that an electromotive force is generated in the power generation coil by changes in the magnetic field of a magnetic field generating source, and a plate-like member is arranged between the magnetic body and the magnetic field generating source and between the two soft magnetic bodies to block the magnetic field generated from the magnetic field generating source toward the center of the magnetic body.

[0009] According to the power generating element of the present disclosure, the magnetic field generated by the magnetic field generating source near the center of the magnetic body is blocked by the plate-shaped member, so that the magnetic field is applied only near the center of the magnetic body, and it is possible to prevent the large Barkhausen effect from occurring only near the center of the magnetic body, thereby enabling a larger generated voltage to be output stably and improving power generation characteristics.

[0010] 1 is a diagram illustrating a configuration of a power generating element according to embodiment 1. FIG. 2 is a diagram illustrating the relationship between the length of a plate-shaped member of a power generating element according to embodiment 1 and the shielding effect. FIG. 3 is a diagram illustrating the positional relationship between a magnetic field generating source and a power generating element according to embodiment 1. FIG. 4 is a diagram illustrating the effect of a plate-shaped member of a power generating element according to embodiment 1. FIG. 5 is a diagram illustrating another effect of a plate-shaped member of a power generating element according to embodiment 1. FIG. 6 is a cross-sectional schematic diagram of a reflective optical encoder using a power generating element according to embodiment 1. FIG. 7 is a diagram illustrating an example of a magnetic material of a power generating element according to embodiment 1. FIG. 8 is a diagram illustrating an example of a soft magnetic material of a power generating element according to embodiment 1. FIG. 9 is a diagram illustrating an example of the structure of a plate-shaped member of a power generating element according to embodiment 2. FIG. 10 is a diagram illustrating an example of the structure of a plate-shaped member of a power generating element according to embodiment 2. FIG. 11 is a diagram illustrating an example of the structure of a power generating element according to embodiment 3. FIG. 12 is a schematic diagram illustrating the assembly of a power generating element according to embodiment 3. FIG. 13 is a schematic diagram illustrating the assembly of a power generating element according to embodiment 3. FIG. 14 is a schematic diagram illustrating an example of the structure of a power generating element according to embodiment 3.

[0011] Preferred embodiments of the power generating element according to the present disclosure will be described below with reference to the drawings. Note that the same contents and corresponding parts are assigned the same reference numerals, and detailed description thereof will be omitted. Similarly, in the following embodiments, redundant description of configurations assigned the same reference numerals will be omitted. Note that the embodiments described below are limited to technologies suitable for implementing the present disclosure, but the technical scope of the present disclosure is not limited to the following embodiments and drawings.

[0012] 1 shows the configuration of a power generating element 100 according to embodiment 1. A power generating coil 2 made of conductive wire is wound around a magnetic body 1 made of a magnetic material, and soft magnetic bodies 3 made of a soft magnetic material are arranged around the magnetic body 1 at both ends of the magnetic body 1. A magnetic field generating source 4, such as a magnet, is arranged near the magnetic body 1, generating a magnetic field 5 around it.

[0013] The magnetic body 1 used in the first embodiment can produce the Large Barkhausen effect. The Large Barkhausen effect is a phenomenon in which, when the magnetic body 1 is magnetized, the internal domain walls of the magnetic body 1 move simultaneously, reversing the magnetization direction in an extremely short time. A Vicaloy alloy (FeCoV alloy) can be used as the magnetic body 1 that produces the Large Barkhausen effect. To produce the Large Barkhausen effect, it is necessary to control the internal stress distribution and composition distribution to create a structure in which the coercive force differs between the outer periphery and the center. Therefore, for example, a Vicaloy alloy with a wire diameter of 0.1 mm to 1 mm is drawn into a wire shape and then twisted to obtain a magnetic body 1 with a structure in which the coercive force differs between the outer periphery and the center. Note that this is an example and does not limit the wire diameter of the magnetic body 1.

[0014] The power generating coil 2 is a coil in which conductive wire is wound, and is arranged so as to wrap around and surround the magnetic body 1, so that the magnetic flux passing through the magnetic body 1 is interlinked. Due to the large Barkhausen effect of the magnetic body 1, when the magnetic flux inside the magnetic body 1 changes, the magnetic flux passing through the power generating coil 2 also changes. As a result, an electromotive force is generated in the power generating coil 2 by electromagnetic induction, and the power generating coil 2 can function as a power generating element 100.

[0015] The power generation coil 2 using conductive wire can be made of copper wire with an insulating coating, and is formed by winding the wire around a bobbin. In addition to copper wire, gold wire, silver wire, copper alloy wire, aluminum wire, aluminum alloy wire, etc. may also be used. The diameter of the conductive wire is selected based on the diameter of the magnetic body 1 to be wound, the size of the power generation element 100, etc.

[0016] A magnetic field generating source 4 is disposed around the magnetic body 1. Two magnetic poles, a north pole and a south pole, are used as the magnetic field generating source 4 to generate a magnetic field 5. In the example of FIG. 1 , the magnetic field generating source 4 is a circular, flat magnet that can rotate in the A direction. Half of the circular surface facing the power generating element 100 is the north pole, and the other half is the south pole. It is also possible to use one or more pairs of north and south poles as the magnetic field generating source 4 to generate the magnetic field 5. The magnetization direction of the magnetic field generating source 4 is preferably a direction that intersects with the surface 4 a of the magnetic field generating source 4 that faces the power generating element 100. In one example, the magnetic field generating source 4 is preferably magnetized so that magnetic flux emerges from the surface forming the north pole of the magnetic field generating source 4 toward the power generating element 100 and enters the surface forming the south pole from the power generating element 100 side. In particular, the magnetization direction is preferably perpendicular or close to perpendicular to the surface 4 a facing the power generating element 100. However, this is an example and does not limit the magnetization direction.

[0017] It is preferable to use a permanent magnet as the magnetic field generating source 4. However, any other material than a permanent magnet may be used as long as it can generate a stable external magnetic field, and an electromagnet may also be used.

[0018] A soft magnetic body 3 is disposed at each end of the magnetic body 1. The soft magnetic body 3 is configured to include a soft magnetic material in which magnetic pole reversal and the like easily occurs and which exhibits a lower coercive force than the magnetic body 1 used in the first embodiment. It is desirable that the soft magnetic body 3 has a higher magnetic permeability and saturation magnetic flux density than the magnetic body 1. The soft magnetic body 3 has an insertion portion 31 through which the magnetic body 1 is inserted, and is configured to come into contact with the magnetic body 1 inside the insertion portion 31. The soft magnetic body 3 has a magnetic collecting effect that collects magnetic flux from the magnetic field generating source 4.

[0019] In the first embodiment, the plate-shaped member 351 is made of the same soft magnetic material as the soft magnetic body 3. Cold-rolled steel plate is suitable as a soft magnetic material because it can be precisely processed into the desired shape and is inexpensive. Other materials that can be used include soft ferrite, permalloy, permendur, silicon steel, amorphous magnetic alloys, nanocrystalline magnetic alloys, and sendust. For example, if a material with high magnetic permeability and high saturation magnetic flux density, such as permendur, is formed into a thin tape and attached, the plate-shaped member 351 can be made thinner, installation is simple, and the overall power generating element can be made smaller. Alternatively, the soft magnetic material may be processed into particles and incorporated into a plastic material to form a plate.

[0020] The plate-shaped member 351 does not need to be made of the same material as the soft magnetic body 3, and may be made of a magnetic material. The plate-shaped member 351 may also be made of a non-magnetic metal such as copper or aluminum. If the plate-shaped member 351 is made of a magnetic material, the magnetic flux collecting effect may be too high, and the magnetic flux passing from the soft magnetic body 3 to the magnetic body 1 may be blocked. For this reason, the ease with which magnetic flux passes through the plate-shaped member 351 may be adjusted by changing the size (thickness, length, width) and gap according to the magnetic characteristics of the magnetic material used.

[0021] Furthermore, when made of a non-magnetic material, eddy currents are generated in a direction that cancels out changes in the magnetic field, which has the effect of shielding the magnetic field. However, when the changes in the magnetic field are small, for example, when the magnetic field generating source described below rotates at a low rotation speed, the effect of shielding the magnetic field is reduced.

[0022] For this reason, the plate-shaped member 351 may be made of a combination of magnetic and non-magnetic materials. This makes it possible to adjust for the magnetic flux that would be too strong if magnetic material were used alone, and would end up shielding the magnetic flux that passes from the soft magnetic material 3 to the magnetic material 1, by combining it with a non-magnetic material. Furthermore, the magnetic material can shield the magnetic field even when the magnetic field generating source has a low rotation speed, making it possible to increase the generated voltage.

[0023] Furthermore, the cross-sectional area of ​​the plate-like member 351 is smaller than that of the magnetic body 1. If the cross-sectional area of ​​the plate-like member 351 is larger than that of the magnetic body 1, most of the magnetic field generated by the magnetic field generating source 4 passes through the plate-like member 351, preventing the magnetic field from reaching the magnetic body 1 and resulting in a small generated voltage.

[0024] The plate-shaped member 351 is disposed substantially parallel to the magnetic body 1 and between the magnetic field generating source 4 and the magnetic body 1. In the first embodiment, the longitudinal direction of the plate-shaped member 351 is configured to extend to a position that covers the soft magnetic body 3. However, the plate-shaped member 351 does not need to extend to a position that covers the soft magnetic body 3; if the plate-shaped member 351 extends to about half the distance between the two soft magnetic bodies 3a and 3b, it will have a shielding effect on the magnetic field from the magnetic field generating source 4 to the vicinity of the center of the magnetic body 1. In other words, if the plate-shaped member 351 is disposed in a position facing the center of the magnetic body 1, the shielding effect on the magnetic field to the vicinity of the center of the magnetic body 1 will be greater. Note that the center and the vicinity of the center of the magnetic body 1 will be referred to as the center in the following description.

[0025] An example of the relationship between the length of the plate-like member 351 and the shielding effect is shown in Figure 2. Even if the length is short, the presence of the plate-like member 351 provides a shielding effect, and a length of half the distance L between the soft magnetic materials 3a and 3b (L / 2 in Figure 2) provides a sufficient shielding effect. Furthermore, the shielding effect saturates at distances L or greater, so the length of the plate-like member 351 does not need to be greater than distance L.

[0026] 3 shows the positional relationship between the magnetic field generating source 4 and the power generating element 100 according to the first embodiment, and is a top view of FIG. 1. The magnetic field generating source 4 applies a magnetic field to the power generating element 100 by rotating around a rotation center 6. The power generating element 100 is disposed in a position where the magnetic body 1 of the power generating element 100 is displaced in the radial direction from the rotation center 6 of the magnetic field generating source 4 when viewed from the axial direction.

[0027] 4 , in the power generating element 100 configured as described above, the magnetic field generated by the magnetic field generating source 4 in the central portion of the magnetic body 1 is blocked by the plate-like member 351. This allows the magnetic field to be applied only near the center of the magnetic body, thereby preventing the large Barkhausen effect from occurring only in the central portion of the magnetic body 1. In other words, the magnetic field directed from the magnetic field generating source 4 to the central portion of the magnetic body 1 is either returned directly to the magnetic field generating source 4 by the plate-like member 351, or passed from the end of the plate-like member 351 through the soft magnetic body 3 and applied to the end of the magnetic body 1 that is in contact with the soft magnetic body 3. With this configuration, the large Barkhausen effect occurs over a wide range of the magnetic body 1, improving power generation performance and providing a stable output with little variation in generated voltage.

[0028] Furthermore, if the plate-like member is made of a soft magnetic material or a magnetic material, the magnetic field generated by the large Barkhausen effect of the magnetic material passes from magnetic body 1 through soft magnetic body 3, then through plate-like member 351, and returns from soft magnetic body 3 to magnetic body 1, as shown in Figure 5. This allows magnetic flux to pass easily, resulting in a large change in the magnetic field, and a large generated voltage can be obtained by electromagnetic induction in power generation coil 2. This makes it possible to provide a power generation element that can output a stable, high voltage. In Figure 5, the longitudinal direction of plate-like member 351 is configured to extend to a position that covers soft magnetic body 3, but the vertical axis in Figure 2 may be replaced with the ease of magnetic flux passage. Even if plate-like member 351 is approximately half the distance L between two soft magnetic bodies 3a and 3b, if it is placed in the path of magnetic flux, the magnetic resistance in that portion will be small, and more magnetic flux can pass through power generation coil 2 than if plate-like member 351 were not provided.

[0029] 1, a gap is provided between the plate-like member 351 and the soft magnetic bodies 3a and 3b, but by bringing the soft magnetic body 3 and the plate-like member 351 into contact, the magnetic field passes through the soft magnetic body 3 without passing through the air, making it easier for the magnetic flux to pass, thereby obtaining a larger generated voltage. When a gap is provided, the plate-like member 351 may be supported at a distance from the soft magnetic bodies 3a and 3b by surrounding it with a non-magnetic, non-conductive material, such as by molding the plate-like member 351 with resin or by adhering it to a resin case.

[0030] <Characteristics of the power generating element> By using the power generating element 100 that stably generates electromotive force, the electromotive force generated in the power generating element 100 can be used as a power source for driving an IC (Integrated Circuit). In addition, by utilizing the fact that the magnetic field 5 generated by the large Barkhausen effect fluctuates sharply and the power generated from the power generating coil 2 by electromagnetic induction is pulsed, the power generating element 100 can be used as a magnetic sensor that notifies the generation of the magnetic field 5 by a pulse voltage.

[0031] Furthermore, by utilizing the stable power supply and pulse characteristics of the power generating element 100, the power generating coil 2 of the power generating element 100 can be connected to an IC, and the IC can operate using the pulsed power generated by the power generating element 100 as a power source, and at the same time, the IC can be used as a power-less magnetic sensor 50 that detects the generation of pulses from the power generating element 100, and can also be used as a reflective optical encoder 200 equipped with the power-less magnetic sensor 50. Figure 6 shows a schematic cross-sectional view of the reflective optical encoder 200.

[0032] The reflective optical encoder 200 is attached to a motor 51. A rotary shaft 53 is connected to a motor rotary shaft 52 of the motor 51, and a hub member 54 with a disk-shaped scale plate 55 attached is fixed to the rotary shaft 53. The scale plate 55 is covered by a substrate 60, a housing 61 disposed around the periphery, and a housing 62 through which the rotary shaft 53 passes. The non-powered magnetic sensor 50 is disposed on the outer surface of the substrate 60, and a light-emitting unit 57 that emits irradiated light indicated by arrow 49 and a light-receiving unit 58 that receives reflected light indicated by arrow 56 are disposed on the inner surface.

[0033] The hub member 54 is provided with magnetism. To provide the hub member 54 with magnetism, a magnet 59 is fixed to the back surface of the hub member 54. Alternatively, the magnet 59 can be disposed between the disk-shaped scale plate 55 and the hub member 54. In this case, the process of fixing the hub member 54 and the magnet 59 can be omitted, improving production efficiency. Furthermore, by molding the magnet 59 into the shape of the hub member 54, the magnet 59 has the function of the hub member 54, which reduces the number of constituent parts and improves production efficiency.

[0034] The hub member 54 can be made of a material such as plastic with magnetic particles dispersed therein, and can be easily formed into various shapes by injection molding. The hub member 54 is not limited to a material such as plastic with magnetic particles dispersed therein, and may also be made of ferrite, alnico (Al-Ni-Co), or rare earth elements.

[0035] In the reflective optical encoder 200, when the rotating shaft 53 rotates, the light emitted from the light-emitting unit 57 is reflected by a pattern formed on the scale plate 55 and composed of high-reflectivity areas and low-reflectivity areas, and the light-receiving unit 58 detects the change in the amount of reflected light, thereby detecting the rotation angle and rotation speed. Furthermore, the power generating element 100 generates power due to changes in the direction of the magnetic force emitted from the hub member 54, thereby detecting the number of rotations from a reference position. Because the rotating shaft 53 rotates together with the motor rotating shaft 52 of the motor 51, the reflective optical encoder 200 can detect the rotation angle, number of rotations, and rotation speed of the motor 51 by detecting the rotation angle, number of rotations, and rotation speed of the rotating shaft 53.

[0036] <Other Configurations and Materials of the Power Generating Element> Configurations and materials that can be used for the power generating element 100 of the first embodiment other than those described above will now be described. In addition to the Vicaloy alloy, permalloy alloys (NiFe alloys), amorphous alloys, etc. can be used for the magnetic body 1 of the first embodiment. Furthermore, in order to control the coercive force, in addition to wire drawing and twisting, bending, heat treatment, plating, chemical treatment, and other surface treatments can be used.

[0037] The coercive force can also be controlled by adding additives to these alloy materials. In the first embodiment, the magnetic body 1 is in the form of a wire. However, as shown in FIG. 7, a sheet-like magnetic body 16 can also be wound with a power-generating coil 2 and used. While a wire diameter of 0.1 mm to 1 mm was used for the magnetic body 1, this is not limited thereto, and wire diameters of less than 0.1 mm and wire diameters greater than 1 mm can also be used. Furthermore, in the first embodiment, the magnetic body 1 has a circular cross-sectional shape. However, this is not limited thereto, and the magnetic body 1 can also have a cross-sectional shape of a polygon such as a square, a thin flat plate, or the like.

[0038] Cold-rolled steel sheet is suitable as the material for the soft magnetic body 3 because it can be precisely processed into the desired shape and is inexpensive. Other materials that can be used for the soft magnetic body 3 include soft ferrite, permalloy, permendur, silicon steel, amorphous magnetic alloys, nanocrystalline magnetic alloys, and sendust, as long as the soft magnetic body 3 has a lower coercive force than the magnetic body 1.

[0039] The soft magnetic material can also be processed into particles and used by incorporating them into a plastic material, etc. The soft magnetic body 3 made of this plastic material has the advantage that it can be easily formed into various shapes by injection molding, etc.

[0040] In addition, although the soft magnetic body 3 has been described as having a rectangular parallelepiped shape with holes, it may also be, for example, a soft magnetic body 3c having an elliptical cross section as shown in Fig. 8(a) or a U-shaped soft magnetic body 3d as shown in Fig. 8(b). The soft magnetic bodies 3c and 3d are pressed and held against the magnetic body 1 by an adhesive (not shown), which allows stable contact between the magnetic body 1 and the soft magnetic bodies 3c and 3d, stabilizing the change in the magnetization direction caused by the large Barkhausen effect in the magnetic body 1 and achieving power generation characteristics with little fluctuation.

[0041] Embodiment 2. In the first embodiment, an example was shown in which the plate-like member 351 was made of a thin plate and was arranged with a gap between it and the soft magnetic material 3, but in the second embodiment, as shown in Fig. 9, a notch 9 is provided in a predetermined range from the center of the plate-like member 352 (hereinafter referred to as the central portion), and both ends of the plate-like member 352 are formed so that the cross-sectional area is larger than that of the central portion where the notch is formed. In addition, the soft magnetic material 3 and the plate-like member 352 are in contact with each other.

[0042] By providing the cutout portion 9, the magnetic path area in the central part of the plate-shaped member 352 is reduced, thereby reducing the proportion of magnetic flux that returns directly to the magnetic field generating source 4 after passing through the plate-shaped member 352 without passing through the soft magnetic material 3, and by increasing the magnetic field applied to the magnetic material 1, the generated voltage is increased.

[0043] 9, when the length of the plate-like member 352 is L and the thickness is t, it is desirable that the depth of the notch is t / 3 to 2t / 3 and the width of the notch is L / 6 to L / 3, for example. However, it goes without saying that the above-mentioned effects can be achieved with dimensions other than these.

[0044] With this configuration, compared to the first embodiment, the magnetic field generated near the center by the magnetic field generating source 4 passes more easily through the ends of the plate-shaped member 352, and the magnetic field applied from the ends of the plate-shaped member 352 through the soft magnetic body 3 to the ends of the magnetic body 1 is strengthened. Furthermore, by bringing the soft magnetic body 3 and the plate-shaped member 352 into contact, the magnetic field passes through the soft magnetic body 3 without passing through the air, making it easier for magnetic flux to pass, thereby obtaining a larger generated voltage.

[0045] 9, even if the plate-shaped member 353 is provided with inclined portions 10 so that the cross-sectional area of ​​the plate-shaped member 353 becomes larger at both ends compared to the central portion, the magnetic path area at the central portion of the plate-shaped member 353 can be reduced, achieving the same effect as providing the cutout portions 9. As an example, in FIG. 10, the plate-shaped member 353 may be formed so that the thickness at both ends is t and the thickness is gradually reduced toward the length L / 2 at an angle.

[0046] Although the example in which the soft magnetic material 3 and the plate-like members 352 and 353 are in direct contact has been shown, the plate-like members 352 and 353 may be fixed to the soft magnetic material by bonding with an adhesive layer, for example. In this case, the magnetic resistance due to the slight gap caused by the adhesive layer is small, and therefore, a large generated voltage can be obtained, similar to the configuration in which the soft magnetic material 3 and the plate-like members 352 and 353 are arranged with a gap therebetween as in the first embodiment.

[0047] Embodiment 3. In Embodiments 1 and 2, the plate-shaped member 351 and the soft magnetic body 3 are separate members, but as shown in Figure 11, the plate-shaped member 351A and the soft magnetic body 3A may be integrally formed in a U-shape. In this case, the thickness of the plate-shaped member 351A is made thinner than the soft magnetic body 3A. Compared to when the plate-shaped members 352, 353 shown in Figures 9 and 10 are simply in contact with the soft magnetic body 3, air is less likely to get into the boundary between the plate-shaped member 351A and the soft magnetic body 3, which reduces magnetic resistance and makes it easier for magnetic flux from the magnetic field 5 to pass, resulting in a larger generated voltage. In addition, the number of parts can be reduced, which has the effect of reducing costs.

[0048] Fig. 12 is a schematic diagram of the assembly of the power generation element 100 of Fig. 11. The power generation coil 2 is positioned on a structure in which a plate-like member 351A and a soft magnetic body 3A are integrally formed, and the magnetic body 1 is inserted and fixed into a hole provided in the soft magnetic body 3A and into the hollow core portion inside the power generation coil 2. Members for positioning the power generation coil 2 and adhesive members for fixing the magnetic body 1 to the hole are omitted from the figure.

[0049] FIG. 13 is another schematic diagram of assembling the power generation element 100 of FIG. 11 . The upper portion of the soft magnetic body 3B of a structure in which the plate-shaped member 351B and the soft magnetic body 3B are integrally formed may be cut out into a U-shaped groove. With the magnetic body 1 inserted into the power generation coil 2, both ends of the magnetic body 1 may be inserted into the U-shaped groove from above, as shown in FIG. 14 , and the magnetic body 1 may be fixed to the soft magnetic body 3B. The structure for positioning the magnetic body 1 inserted into the power generation coil 2 and for fixing the magnetic body 1 in the U-shaped groove is omitted. Whether or not to fill the groove after inserting the magnetic body 1 into the U-shaped groove is determined appropriately. As described above, the structure of the power generation element of embodiment 3 simplifies the positioning and fixing of the magnetic body 1 compared to the cases in which the plate-shaped member 351 and the magnetic body 1 are separate members, thereby reducing the assembly man-hours and achieving cost reductions.

[0050] Although various exemplary embodiments and examples are described in this disclosure, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless variations not illustrated are anticipated within the scope of the technology disclosed in the specification. For example, this includes cases where at least one component is modified, added, or omitted, or where at least one component is extracted and combined with components of another embodiment.

[0051] Various aspects of the present disclosure are described below as appendices. (Appendix 1) A power generating element comprising: a magnetic body made of a magnetic material that generates the large Barkhausen effect; a power generating coil in which magnetic flux passing through the magnetic body interlinks; and two soft magnetic bodies having insertion portions through which the magnetic body is inserted, the soft magnetic bodies being provided at both ends of the magnetic body so as to come into contact with the magnetic body when the magnetic body is inserted through the insertion portions, wherein an electromotive force is generated in the power generating coil in response to changes in the magnetic field of a magnetic field generating source, the power generating element being characterized in that a plate-like member is disposed between the magnetic body and the magnetic field generating source and between the two soft magnetic bodies to block the magnetic field generated by the magnetic field generating source and directed toward a center of the magnetic body. (Appendix 2) The power generating element according to Appendix 1, characterized in that the soft magnetic body and the plate-like member are in contact with each other. (Appendix 3) The power generating element according to Appendix 1 or 2, characterized in that both ends of the plate-like member have a larger cross-sectional area than a central portion. (Supplementary Note 4) The power generating element according to Supplementary Note 3, wherein the central portion of the plate-like member is cut out over a predetermined range. (Supplementary Note 5) The power generating element according to Supplementary Note 3, wherein an inclined portion is formed in which the cross-sectional area increases from the central portion toward the end portion of the plate-like member. (Supplementary Note 6) A magnetic sensor using the power generating element according to any one of Supplementary Notes 1 to 5. (Supplementary Note 7) An encoder using the power generating element according to any one of Supplementary Notes 1 to 5.

[0052] 1, 16: magnetic material, 2: power generation coil, 3, 3a, 3b, 3c, 3d, 3A, 3B: soft magnetic material, 4: magnetic field generation source, 5: magnetic field, 9: cutout portion, 10: inclined portion, 50: power-less magnetic sensor, 51: motor, 52: motor rotating shaft, 53: rotating shaft, 54: hub member, 55: scale plate, 56: arrow, 57: light-emitting unit, 58: light-receiving unit, 59: magnet, 60: substrate, 61: housing, 62: housing, 100: power generation element, 200: reflective optical encoder, 351, 351A, 351B, 352, 353: plate-like members.

Claims

1. A generating element comprising: a magnetic body made of a magnetic material that produces a large Barkhausen effect; a generating coil in which magnetic flux passing through the magnetic body is interlinked; and two soft magnetic bodies having an insertion portion through which the magnetic body is inserted and including a soft magnetic material provided at both ends of the magnetic body so as to come into contact with the magnetic body when the magnetic body is inserted into the insertion portion, wherein an electromotive force is generated in the generating coil in response to a change in the magnetic field of a magnetic field generating source, wherein a plate-shaped member that blocks the magnetic field generated from the magnetic field generating source toward the center of the magnetic body is disposed between the magnetic body and the magnetic field generating source and between the two soft magnetic bodies.

2. The power generating element according to claim 1, wherein the plate-like member is disposed opposite the center of the magnetic body.

3. The power generating element according to claim 1 or 2, characterized in that the soft magnetic material and the plate-like member are in contact with each other.

4. A power generating element according to any one of claims 1 to 3, characterized in that the cross-sectional area of ​​both ends of the plate-like member is larger than that of a central portion.

5. The power generating element according to claim 4, characterized in that the central portion of the plate-like member is cut out over a predetermined range.

6. The power generating element according to claim 4, characterized in that said plate-like member is formed with an inclined portion in which the cross-sectional area increases from the center portion toward the end portion.

7. A power generating element according to any one of claims 1 to 6, characterized in that the plate-like member and the soft magnetic material are integrally formed.

8. A magnetic sensor using the power generating element according to any one of claims 1 to 7.

9. An encoder using the power generating element according to any one of claims 1 to 7.

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