Electric power generation device

Abstract

The present invention addresses the problem of providing an electric power generation device that has high electric power generation performance, is easily manufactured by having a simple structure, and generates electric power by vibration with high performance. An electric power generation device according to the present invention comprises a soft magnetic member, a coil, and a magnetic field generation source. The soft magnetic member has a free end that is movable in one direction, and a supported stationary portion. The coil is disposed so as to be wound around at least a portion of the soft magnetic member. The magnetic field generation source is positioned on the opposite side from the soft magnetic member with respect to a plane that is perpendicular to the longitudinal direction of the soft magnetic member and passes through the free end.

Description

power generation equipment

[0001] The present invention relates to a power generation device.

[0002] In recent years, there has been progress in the development of vibration-powered devices that generate electricity by utilizing familiar vibrations. Such devices could be used for, for example, online monitoring of the temperature of equipment that generates minute vibrations in factories, and for accident prevention by detecting abnormal stress in structures such as bridges and tunnels.

[0003] Patent Document 1 discloses a power generating device having a soft magnetic member, a permanent magnet that applies a magnetic field to the soft magnetic member, and a coil wound around at least a portion of the soft magnetic member. The permanent magnets include a first permanent magnet and a second permanent magnet that is disposed on the opposite side of the first permanent magnet across the soft magnetic member. The portion of the soft magnetic member to which the magnetic field is applied is arranged so that its angle with respect to the magnetic field lines is variable so that the magnetic flux passing through the coil changes in response to an external force.

[0004] Patent Document 2 discloses an inverse magnetostrictive power generating element including a frame yoke made of a magnetic material and having a bent portion for forming a closed magnetic circuit, a magnetic portion formed in part of the frame yoke, a magnetostrictive plate made of a magnetostrictive material, a coil, and a magnet. The magnetic portion has the rigidity and shape to apply a uniform compressive or tensile force to the magnetostrictive plate and is magnetically saturated by the magnetic bias of the magnet, the magnetostrictive plate is attached to the frame yoke so as to be parallel to the magnetic portion, and the coil is wound around a parallel beam portion made of the magnetostrictive plate and the magnetic portion and / or the frame yoke. The power generating element generates electricity when the magnetostrictive plate expands or contracts when an external force is applied.

[0005] Patent Document 3 discloses a magnetostrictive power generation device including a magnetostrictive element for power generation having a magnetostrictive portion formed of electromagnetic steel sheets and a stress control portion formed of an elastic material, and a frame continuous with the magnetostrictive element for power generation, at least a portion of which is composed of a laminate including electromagnetic steel sheets extending from the magnetostrictive portion and an elastic material extending from the stress control portion.

[0006] JP 2023-174153 A JP 2018-148791 A JP 2021-103940 A

[0007] In the power generator disclosed in Patent Document 1, the permanent magnets are arranged to apply a magnetic field perpendicular to the soft magnetic member when no external force is applied. In this power generator, a relatively slight vibration or displacement of the soft magnetic member generates a magnetic field with an in-plane magnetic field component acting in the plane direction of the soft magnetic plate at the tip of the flat-shaped soft magnetic member due to the magnetic field of the arranged magnets. The direction of this in-plane magnetic field component alternates with vibration, generating power. In the power generator disclosed in Patent Document 1, the change in the angle of the tip due to vibration is relatively small, making it difficult to apply a sufficiently large in-plane magnetic field. On the other hand, if the magnetic field of the magnet is strong, depending on the positional relationship, the soft magnetic plate may stick to the magnet and stop vibrating.

[0008] The power generating element disclosed in Patent Document 2 uses an inverse magnetostriction method, which requires the use of a single crystal plate cut so that the crystal orientation with a large magnetostriction constant is in the direction of stress application. As such, magnetostrictive power generating devices require the use of special materials, which increases manufacturing costs and makes it difficult to manufacture them inexpensively.

[0009] The magnetostrictive power generation device using the inverse magnetostriction method disclosed in Patent Document 3 is a magnetostrictive power generation device in which the entire frame, which has a shape with one U-shaped portion and one L-shaped portion, is integrally configured with the magnetostrictive element. In the magnetostrictive power generation device of Patent Document 3, the permanent magnet is fixed to the inside of the tip end of the bent L-shape. This device also requires the use of a special material for the magnetostrictive element, which increases manufacturing costs and makes it difficult to manufacture at low cost.

[0010] An object of the present invention is to provide a high-performance power generating device that generates power by bounce and vibration, which has high power generation performance and is easy to manufacture due to its simple structure.

[0011] The present inventors have conducted extensive research to solve the above problems and have arrived at the present invention. The present invention includes the following aspects.

[0012] (1) A power generating device comprising a soft magnetic member, a coil, and a magnetic field generating source, wherein the soft magnetic member has a free end that is an end that can move in at least one direction and a supported fixed part, the coil is wound around at least a portion of the soft magnetic member, and the magnetic field generating source is arranged on the opposite side of the soft magnetic member with respect to a plane that is perpendicular to the longitudinal direction of the soft magnetic member and passes through the free end.

[0013] (2) The power generating device according to (1), wherein the direction of the magnetic moment of the magnetic field generating source and the direction in which the free end can move are parallel.

[0014] (3) The power generating device of (2), characterized in that when the free end of the soft magnetic member is stationary with no external mechanical force acting on the soft magnetic member, the magnetic field generating source is located on an extension line extending from the free end of the soft magnetic member in the longitudinal direction of the soft magnetic member.

[0015] (4) The power generating device according to any one of (1) to (3), wherein the magnetic field generating source is one or more permanent magnets.

[0016] (5) The power generating device according to (4), characterized in that the permanent magnets are two or more and are formed as a single unit.

[0017] (6) The power generating device of (5), characterized in that the magnetic moments of two or more of the permanent magnets are parallel to the longitudinal direction of the soft magnetic member, perpendicular to the movable direction of the free end, and alternately in opposite directions.

[0018] (7) The power generating device according to (5) above, characterized in that the magnetic moments of the two or more permanent magnets are oriented in a Halbach array.

[0019] (8) The power generating device according to any one of (1) to (7), wherein the magnetic field generating source is fixed by a non-magnetic member.

[0020] (9) A power generating device according to any one of (1) to (8), characterized in that the frequency at which the vibration spectrum of the soft magnetic member is at its maximum is a frequency band at which the vibration spectrum G(ω) of the fixed part, the coil support supporting the coil, and the magnetic field generating source support supporting the magnetic field generating source is less than half the maximum value of G(ω).

[0021] (10) Any of the power generating devices of (1) to (9) characterized in that the soft magnetic member is divided into a transmission section P2, which is the section around which the coil is wound, an introduction section P1, which is closer to the magnetic field source than the transmission section, and a return section P3, which is farther from the magnetic field source than the transmission section, and the average length and average cross-sectional area of ​​the soft magnetic member in the introduction section are P1L and P1A, respectively, the average length and average cross-sectional area of ​​the soft magnetic member in the transmission section are P2L and P2A, respectively, and the average length and average cross-sectional area of ​​the soft magnetic member in the return section are P3L and P3A, respectively, such that P1L / P1A≦P2L / P2A≦P3L / P3A.

[0022] (11) A power generating device according to any one of (1) to (10), characterized in that it comprises a magnetic flux feedback member connected to the side of the soft magnetic member farther from the magnetic field generating source and extending toward the magnetic field generating source.

[0023] (12) A power generating device according to any one of (1) to (11), characterized in that it comprises two or more sets of the soft magnetic member, the coil, and the magnetic field generating source, and the soft magnetic members of each set are connected to each other.

[0024] (13) The power generating device according to any one of (1) to (12), wherein the soft magnetic member includes a first weight for adjusting vibration conditions.

[0025] (14) The power generating device according to (13), characterized in that the first weight is disposed between the magnetic field generating source and the fixed part.

[0026] (15) The power generating device according to (13), wherein the first weight is disposed near the free end of the soft magnetic member.

[0027] (16) The power generating device of (15) is characterized in that it satisfies one or more of the following: [1] the distance between the soft magnetic member and the magnetic field generating source is 1 mm or less; [2] the length of the soft magnetic member is 40 mm or more; and [3] the weight applied to the tip is 0.18 g or more.

[0028] (17) The power generating device according to (14), characterized in that the direction from the fixed portion toward the free end is parallel to the direction of gravity.

[0029] (18) The power generating device according to (14), wherein the direction from the fixed portion toward the free end is perpendicular to the direction of gravity and parallel to the plate surface of the soft magnetic member.

[0030] (19) The power generating device according to (14), wherein the soft magnetic member has one or more weights other than the first weight in a portion other than the free end.

[0031] (20) The power generating device according to (19), characterized in that it comprises two or more weights other than the first weight.

[0032] (21) The power generating device according to (14), characterized in that at least one of the magnetic field generating source and a magnetic field generating source support supporting the magnetic field generating source has one or more weights other than the first weight.

[0033] (22) A power generating device described in any one of (1) to (21), characterized in that the soft magnetic member is flat and the movable direction of the free end is perpendicular to the plate surface of the soft magnetic member.

[0034] (23) A power generating device according to any one of (1) to (22), characterized in that the direction of the magnetic moment of the magnetic field generating source is perpendicular to the longitudinal direction of the soft magnetic member and the plate surface of the soft magnetic member.

[0035] (24) A power generating device described in any one of (1) to (23), characterized in that the region between the free end of the soft magnetic member and the fixed portion is stable due to the magnetic field distribution generated by the magnetic field generating source in the absence of external mechanical force.

[0036] (25) A power generating device according to any one of (1) to (24), characterized in that there are multiple positions where the area between the free end of the soft magnetic member and the fixed portion is stable in the absence of external mechanical force.

[0037] (26) The power generating device according to any one of (1) to (24) above, further comprising an external force applying mechanism for applying a mechanical external force to the soft magnetic member.

[0038] (27) The power generating device according to (26), characterized in that a non-magnetic cover is attached to the soft magnetic member at a position where a mechanical external force is applied by the external force application mechanism.

[0039] (28) A power generating device according to any one of (1) to (27), characterized in that the inner diameter of the coil on the free end side of the soft magnetic member is larger than the inner diameter of the coil on the fixed portion side of the soft magnetic member.

[0040] (29) The power generating device according to any one of (1) to (28) above, characterized in that it is provided with a capacitor.

[0041] (30) The power generating device according to (29), characterized in that the capacitor is connected in parallel with the coil.

[0042] (31) A power generating device characterized in that a cover is attached to cover any of the power generating devices of (1) to (30), and terminals from the coil pass through the cover from the inside to the outside.

[0043] According to the present invention, it is possible to provide a power generating device that has high power generating performance and is easy to manufacture.

[0044] 1 is a diagram schematically illustrating the overall configuration of a first embodiment of a power generating device according to the present invention; FIG. 2 is a diagram illustrating an example of the magnetization characteristics of a soft magnetic member (grain-oriented electromagnetic steel plate) according to the present invention; FIG. 3 is a diagram illustrating an example of an equivalent circuit when a capacitor is connected in parallel to a coil; FIG. 4 is a diagram illustrating the magnetic flux distribution of a magnetic field generation source in a power generating device according to the present invention (when a magnet is used alone: ​​when there is no soft magnetic material); FIG. 5 is a diagram illustrating the relationship between the magnetic flux from the magnetic field generation source and each position of the free end of the soft magnetic member in a power generating device according to the present invention (when a magnet is used alone: ​​when there is no soft magnetic material); FIG. 6 is a diagram illustrating another example of a first embodiment of a power generating device according to the present invention; FIG. 7 is a diagram illustrating an example of a power generating device according to the present invention with a cover attached; FIG. 8 is a diagram illustrating an example of the shape of a soft magnetic member in a power generating device according to the present invention; FIG. 9 is a diagram illustrating an example of an investigation into the relationship between the gap between the soft magnetic member and the magnetic field generation source, the distance between the fixed end of the soft magnetic member and the magnetic field generation source, and the weight of a weight placed on the tip of the soft magnetic member, and the resonance frequency in a power generating device according to the present invention; FIG. 10 is a diagram schematically illustrating the configuration of a second embodiment of a power generating device according to the present invention; and FIG. 11 is a diagram illustrating a third embodiment of a power generating device according to the present invention. FIG. 10 is a diagram schematically showing the configuration of a fourth embodiment of the power generating device according to the present embodiment. FIG. 11 is a diagram schematically showing the configuration of a fifth embodiment of the power generating device according to the present embodiment. FIG. 12 is a diagram schematically showing another example of the configuration of the fifth embodiment of the power generating device according to the present embodiment. FIG. 13 is a diagram schematically showing the configuration of a sixth embodiment of the power generating device according to the present embodiment. FIG. 14 is a graph showing the output voltage and the position of the tip of the soft magnetic plate when a bouncing vibration is generated in the power generating device in the examples.

[0045] <Power Generator> The power generator of the present invention comprises a soft magnetic member, a coil, and a magnetic field generating source. The soft magnetic member has a free end that is an end that is movable in at least one direction, and a supported fixed portion. The coil is wound around at least a portion of the soft magnetic member. The magnetic field generating source is disposed on the opposite side to the soft magnetic member with respect to a plane that is perpendicular to the longitudinal direction of the soft magnetic member and passes through the free end of the soft magnetic member. The coil is supported by a coil support, and the magnetic field generating source is supported by a magnetic field generating source support. The coil support is preferably made of a non-magnetic material or a soft magnetic material, and the magnetic field generating source support is preferably made of a non-magnetic material.

[0046] Hereinafter, an embodiment of the power generating device of the present invention will be described.

[0047] <Embodiment 1>

[0048] A first embodiment of the power generating device of the present invention will be described with reference to FIG.

[0049] Fig. 1 is a diagram schematically showing the overall configuration of a power generating device according to this embodiment. In Fig. 1, the direction indicated by arrow Z1 is defined as the upward direction, and the direction indicated by arrow Z2 is defined as the downward direction. The same applies to Fig. 4 described below. The power generating device 1 is a power generating device that extracts electric power based on an induced current generated in a coil 20 in response to deformation of a soft magnetic member 10 due to vibration. The power generating device 1 shown in Fig. 1 includes a soft magnetic member 10, a coil 20, and a magnetic field generating source 30.

[0050] In the embodiment shown in FIG. 1 , the soft magnetic member 10 is a plate-shaped soft magnetic plate, and the left-right direction of the paper is the longitudinal direction of the soft magnetic plate. The soft magnetic plate has a width perpendicular to the paper. The right end of the soft magnetic plate is a free end 11 that is an end that can move up and down, and the other end is a fixed part 12 that is fastened to a support 50 by a screw 51 that serves as a fixing device, and is supported in a cantilevered manner. The free end 11 is provided so as to be able to bend and displace relative to the fixed part in response to vibration. Note that in the embodiment shown in FIG. 1 , the fixed part 12 is the end opposite the free end 11, but the fixed part 12 is not limited to the end.

[0051] The coil 20 is arranged so as to interlink with the magnetic flux in the soft magnetic member 10, in other words, so as to be wound around the soft magnetic member 10. The magnetic field generating source 30 is, for example, a permanent magnet, and is arranged on the opposite side of the soft magnetic member 10 with respect to a plane P that is perpendicular to the longitudinal direction of the soft magnetic member 10 and passes through the free end 11. The magnetic field generating source 30 is arranged at a predetermined distance from the soft magnetic member 10 so that a magnetic field can be applied to the soft magnetic member 10 and so that the free end 11 of the soft magnetic member 10 is movable. The portion of the soft magnetic member 10 to which the magnetic field is applied is arranged so that the angle with respect to the magnetic field lines of the magnetic field generated by the magnetic field generating source 30 can be changed in accordance with the vibration of the soft magnetic member 10.

[0052] The movable direction of the free end 11 may be parallel to the direction of the magnetic moment of the magnetic field generating source 30 (the direction from the south pole to the north pole of the magnetic field generating source 30). Here, "parallel" does not have to be strictly parallel, and deviation from parallelism is permitted to the extent of an error in assembling the power generating device. By making the movable direction of the free end 11 parallel to the direction of the magnetic moment of the magnetic field generating source 30, the change in the magnetic field applied to the soft magnetic member 10 due to the movement of the free end 11 becomes larger, thereby improving power generation efficiency.

[0053] 1, the magnetic field generating source 30 is disposed on an extension line of the longitudinal direction of the soft magnetic member 10. In the positional relationship between the soft magnetic plate and the magnetic field generating source shown in FIG. 1, the soft magnetic plate bends and the position of the free end changes depending on the gap d between the soft magnetic plate and the magnetic field generating source and the condition of the magnetic field generating source 30.

[0054] (Soft Magnetic Member) The soft magnetic member 10 is a member made of a soft magnetic material. The soft magnetic member 10 may be, for example, iron, cobalt, nickel, or an alloy thereof. The soft magnetic member 10 may also be, for example, made of boron, aluminum, silicon, or an alloy containing any of these elements and iron.

[0055] The soft magnetic member 10 may be a soft magnetic plate such as a pure iron plate, a non-oriented silicon steel plate, an oriented silicon steel plate, an iron-based amorphous ribbon, etc. When a flat soft magnetic plate is used as the soft magnetic member 10, the movable direction of the free end 11 may be a direction perpendicular to the plate surface.

[0056] The direction of the magnetic moment of the magnetic field generating source 30 may be perpendicular to the plate surface. Here, "perpendicular" does not have to be strictly perpendicular, and deviation from perpendicular may be permitted due to errors in assembling the power generating device.

[0057] An example of the characteristics of a soft magnetic member 10 made of a soft magnetic material will be described with reference to FIG. 2. FIG. 2 is a graph showing the magnetization characteristics of a flat grain-oriented electrical steel sheet having a length of 40 mm, a width of 6.7 mm, and a thickness of 0.35 mm. In FIG. 2, the vertical axis represents magnetic flux density [T (tesla)], and the horizontal axis represents magnetic flux density of the applied magnetic field [mT (millitesla)]. The soft magnetic member 10 has high magnetic permeability, and its magnetic flux density varies in the range of approximately −1.7 to +1.7 [T]. The magnetic flux density of the soft magnetic member 10 increases as the magnetic flux density of the applied magnetic field increases, eventually tending to saturate.

[0058] The soft magnetic member 10 is not limited to being made entirely of a soft magnetic material. For example, it may be made by bonding a soft magnetic material to a substrate that is provided so that the angle relative to the magnetic field lines of the magnetic field of the magnetic field generating source 30 can be changed in response to an external force, or by providing a soft magnetic material in the form of a thin film. The thin film soft magnetic material may be formed on the substrate by, for example, coating, plating, vapor deposition, sputtering, or the like.

[0059] (Coil) The coil 20 is arranged so that the magnetic flux of the soft magnetic member 10 interlinks with the coil 20, in other words, so that it is wound around the soft magnetic member 10. The coil 20 may be arranged so that it is wound around at least a portion of the soft magnetic member 10 in the extension direction of the soft magnetic member 10 (the central axis direction of the coil 20). The material of the coil 20 is not particularly limited, and it may be, for example, copper wire. In the situation shown in FIG. 1 , the larger the amplitude at the free end, the greater the amount of power generation. When the amplitude becomes large, the inner diameter of the coil on the free end side determines the limit of the amplitude (maximum amplitude). Therefore, in order to generate power efficiently, it is desirable to make the inner diameter of the coil on the free end side larger than the inner diameter of the coil on the fixed portion side.

[0060] Furthermore, since the coil has an inductance component L (H) and a resistance component R (Ω), it is desirable to adjust the internal impedance Zin (Ω) to match the load impedance Zex (Ω) and the frequency of the vibration source. Although it depends on the load Zex (Ω), in the case of general-purpose use, it is desirable to install a capacitor of appropriate capacity as needed to reduce Zin (Ω) on the generator side. Furthermore, it is desirable to install a capacitor of appropriate capacity in parallel with the coil depending on the frequency. Figure 3 shows an example of an equivalent circuit when a capacitor of capacitance C is connected in parallel to a coil with inductance L and resistance R.

[0061] (Magnetic Field Generation Source) In the embodiment shown in FIG. 1, the magnetic field generation source 30 is provided to apply a magnetic field to the vicinity of the free end 11 of the soft magnetic member 10 .

[0062] The magnetic field generation source 30 may be fixed by a non-magnetic jig. By fixing the magnetic field generation source 30 by the jig, it will not be displaced in response to vibration, and since the jig is non-magnetic, it is possible to fix the magnetic field generation source 30 without affecting the magnetic field distribution.

[0063] When no external mechanical force is applied to the soft magnetic member, the free end of the soft magnetic member is stationary. In this state, the magnetic field generating source may be located on an extension line extending from the free end of the soft magnetic member in the longitudinal direction of the soft magnetic member.

[0064] The magnetic field generating source 30 may be a permanent magnet. A permanent magnet can maintain its magnetic properties without receiving an external magnetic field or current, and is therefore preferable as the magnetic field generating source 30. The permanent magnet may be, for example, a ferrite magnet, a neodymium magnet, a samarium-cobalt magnet, an alnico magnet, or the like.

[0065] For example, two or more permanent magnets may be arranged symmetrically with respect to the extension line of the soft magnetic member 10. When two or more permanent magnets are arranged as a single unit, the magnetic flux penetrating the soft magnetic member 10 can be increased due to the effect of the demagnetizing field, which results in a larger change in the magnetic flux passing through the coil and an increased amount of power generation, which is preferable.

[0066] In this embodiment, as will be described later with reference to Figures 4 and 5, when the magnet is arranged so that the magnetic moment is perpendicular to the surface of the flat soft magnetic member (soft magnetic plate), the direction of the magnetic field component acting on the soft magnetic member 10 changes depending on whether the free end 11 of the soft magnetic member 10 is displaced upward or downward in response to vibration. Therefore, the direction of the magnetic flux passing through the soft magnetic member alternates between its upper and lower limits in response to vibration.

[0067] In particular, when a permanent magnet with magnetic poles as shown in Figure 4 is arranged and d is relatively small, the tip of the soft magnetic material will be biased toward either the upper or lower corner of the permanent magnet, where the magnetic flux density is high, due to the magnetic force, as shown in Figure 5(a) or Figure 5(b). This is because the positional relationship shown in Figure 5(c) (where the magnetic field is strictly perpendicular to the plate surface) is magnetically unstable. Furthermore, when d is relatively large or the soft magnetic material is thick and rigid, the result will be closer to the state shown in Figure 5(c). The optimal d can be determined based on the shape and rigidity of the soft magnetic material, the performance of the magnet, and the conditions of the vibration source.

[0068] In the example of the characteristics of grain-oriented electrical steel sheet shown in Figure 2, the magnetic flux density varies within a range of approximately -1.7 to +1.7 T. In this case, a tendency for saturation is observed when the magnetic flux density of the applied magnetic field is around 5 mT. In other words, when an external magnetic field of 5 mT or more is applied as an in-plane magnetic field due to vibration, a large change in magnetic flux density of around 3.4 T occurs. However, when the external magnetic field is 5 mT or less due to vibration, the magnetic flux density changes in proportion to the strength of the applied external magnetic field. Therefore, it is important to have a magnetic field distribution and magnet arrangement that will produce a larger change in the in-plane magnetic field.

[0069] In order to strengthen the magnetic field generated by the magnetic field generating source 30, a yoke made of a magnetic material that forms a magnetic path together with the magnetic field generating source 30 may be provided.

[0070] <Power generation principle> The power generation principle of the power generation device 1 will be described with reference to Figures 1, 4, and 5. Figure 4 is a schematic diagram showing the magnetic flux distribution of the soft magnetic member 10 and the magnetic field generation source 30 (when there is no soft magnetic material and the magnet is alone), and Figures 5(a) to 5(c) are schematic diagrams showing the positional relationship between the position of the free end and the magnetic flux distribution when the soft magnetic member 10 vibrates, and are enlarged views of the dashed line portion in Figure 4.

[0071] In the embodiment shown in FIG. 1 , as described above, the soft magnetic member 10 is cantilevered by the support 50. Therefore, when vibration is applied to the soft magnetic member 10, the soft magnetic member 10 vibrates up and down around its fixed portion 12 as a fulcrum. At this time, the magnetic flux passing through the coil 20 changes over time, generating an induced current in the coil 20. In the following description, the posture of the soft magnetic member 10 when no vibration is applied is referred to as the "basic posture." FIGS. 5( a) and 5(b) show the soft magnetic member 10 in the basic posture. The basic posture is a state in which the region between the free end and the fixed portion of the soft magnetic member 10 is stable due to the magnetic field distribution generated by the magnetic field generating source 30 when there is no mechanical external force on the soft magnetic member 10. When d is relatively small, the soft magnetic member is thin, and its rigidity is low, multiple stable points are formed at the tip of the soft magnetic member.

[0072] Figure 5(a) shows the positional relationship between the free end 11 of the soft magnetic member 10 displaced upward and the magnetic field lines of the magnet. Figure 5(b) shows the positional relationship between the free end 11 of the soft magnetic member 10 displaced downward and the magnetic field lines of the magnet. In Figures 5(a) and 5(b), the arrows in the soft magnetic member indicate the direction of magnetic flux flowing into the soft magnetic member 10 in the basic position due to the magnetic field applied to the soft magnetic member 10 by the magnetic field generating source 30.

[0073] As shown in Figures 5(a) and 5(b), when the tip of the soft magnetic member 10 is displaced upward or downward due to the magnetic flux with high magnetic flux density at the corner of the magnetic field generating source 30, a large in-plane magnetic field component F1 or F2 acting in the surface direction of the soft magnetic member 10 is generated in the soft magnetic member 10 with even a slight vibration (displacement).

[0074] The in-plane magnetic field component F1 acts on the soft magnetic member 10 to align the magnetic flux within the soft magnetic member 10 in the same direction as the in-plane magnetic field component F1. As a result, in the soft magnetic member 10 in the state shown in Fig. 5(a), magnetic flux is generated that flows from the free end toward the fixed portion. In other words, magnetic flux is generated that penetrates the soft magnetic member 10 from the free end toward the fixed portion.

[0075] As shown in Figure 5(b), when the tip end of the soft magnetic member 10 is displaced downward, an in-plane magnetic field component F2 acting in the plane direction of the soft magnetic member 10 is generated in the soft magnetic member 10. The in-plane magnetic field component F2 is a magnetic field component generated in the opposite direction to F1. The in-plane magnetic field component F2 acts to align the magnetic flux within the soft magnetic member 10 in the same direction as the in-plane magnetic field component F2. As a result, in the soft magnetic member 10 in the state shown in Figure 5(b), a magnetic flux is generated that flows from the end end toward the tip end.

[0076] When the amplitude of the soft magnetic member 10 is large, the soft magnetic member 10 vibrates back and forth toward the basic postures shown in Figures 5(a) and 5(b), and the free end is displaced up and down repeatedly. That is, the state shown in Figure 5(a) and the state shown in Figure 5(b) are repeated alternately. In the power generating device 1 according to this embodiment, an induced current is generated in the coil 20 each time the free end of the soft magnetic member 10 is displaced up and down, and electric power can be extracted.

[0077] On the other hand, when the amplitude is relatively small, the vibration occurs back and forth around one of the basic positions shown in Fig. 5(a) and Fig. 5(b). In this case, the power that can be extracted is smaller than when the amplitude is large, but it is still possible to extract power.

[0078] 1 and 4, the direction indicated by the arrow Z1 is defined as the upward direction and the direction indicated by the arrow Z2 is defined as the downward direction, but the vibration direction of the soft magnetic member 10 in the power generating device shown in Fig. 1 is not limited to the up and down vertical direction. For example, the same effect can be obtained even when the soft magnetic member 10 vibrates left and right in the horizontal direction.

[0079] Other Embodiments In the above-described embodiment, an example was shown in which the soft magnetic member 10 bends in response to vibration, thereby displacing the tip portion (free end) thereof. In the power generating device of the present invention, the soft magnetic member 10 is not limited to a member that bends in response to vibration. In other words, the soft magnetic member 10 may be made of a material with high rigidity.

[0080] The fixed portion 12 of the soft magnetic member 10 does not necessarily need to be directly connected to the support 50, but may be connected via a non-magnetic or soft magnetic substrate. When the soft magnetic member 10 is made of a highly rigid material, for example, the soft magnetic member 10 may be provided such that its distal end is rotatably supported on the support 50, thereby varying the angle and position of the tip of the soft magnetic member 10 relative to the magnetic field lines of the magnetic field of the magnetic field generating source 30. Alternatively, for example, the distal end of the soft magnetic member 10 may be supported by an elastic body such as a spring, such that the angle of the tip of the soft magnetic member 10 relative to the magnetic field lines of the magnetic field of the magnetic field generating source 30 varies with elastic deformation of the elastic body. Even with these configurations, an in-plane magnetic field is generated within the soft magnetic member 10, as in the above-described embodiment, and the magnetic flux passing through the coil 20 can be changed. Therefore, an induced current is generated in the coil 20, allowing power to be extracted.

[0081] The vibration applied to the soft magnetic member 10 is not limited to continuous vibration. For example, the portion of the soft magnetic member 10 to which the magnetic field is applied by the magnetic field generating source 30 may be displaced in response to an instantaneous external force such as a flick.

[0082] A weight for adjusting vibration conditions may be disposed on the soft magnetic member 10. The weight may be disposed, for example, between the magnetic field generating source 30 and the fixed part 12. Alternatively, the weight may be disposed near the free end 11 of the soft magnetic member 10. Disposing the weight in such a position makes it easier to obtain the effect of adjusting the resonant frequency, as will be described later.

[0083] The power generating device 1 may also include an external force application mechanism that applies an external mechanical force to the soft magnetic member 10. The power generating device of the present invention generates electricity by bounce and vibration, and by including the external force application mechanism, it is possible to directly apply vibration to the soft magnetic member 10. A non-magnetic cover may be provided at a position where an external mechanical force is applied to the soft magnetic member 10. If the cover is non-magnetic, it is possible to protect the position where the external mechanical force is applied without affecting the magnetic field distribution.

[0084] Furthermore, in the above-described embodiment, an example has been described in which both the coil 20 and the magnetic field generation source 30 are fixed, but the coil 20 and the magnetic field generation source 30 may be displaceable. Even when the coil 20 and the magnetic field generation source 30 are displaceable, the effects of the present invention can be obtained as long as the portion of the soft magnetic member 10 to which the magnetic field is applied by the magnetic field generation source 30 is configured so that the angle relative to the magnetic field lines caused by the magnetic field is variable so that the magnetic flux passing through the coil 20 changes in response to an external force.

[0085] Up to this point, we have mainly used Figure 1 to explain power generation using vertical vibration components and bounces, but if the vibration of the vibration source mainly contains components perpendicular to gravity, it is necessary to devise a way to install the power generation device. This is particularly important when a weight for adjusting the resonant frequency is attached to the tip of the soft magnetic material, in order to eliminate the influence of displacement due to gravity of the weight and to adjust the positional relationship between the tip of the soft magnetic material and the magnetic field generation source.

[0086] 6 shows an example of a method for installing a power generating device to which a weight 70 is attached, in the case where the direction from the fixed portion of the soft magnetic member 10 fixed to the support 50 toward the tip end is parallel to the direction of gravity. In both (a) and (b) of FIG. 6, the direction of gravity is from top to bottom on the paper, and (a) and (b) are views seen from different sides at 90° angles.

[0087] 7 shows an example of a method for installing a power generating device with a weight 70 attached, in which the direction from the fixed portion toward the tip of the soft magnetic member 10 is perpendicular to the direction of gravity and parallel to the plate surface of the soft magnetic member 10. In Fig. 7, (a) is a diagram showing the direction of gravity from the top to the bottom of the paper, and (b) is a diagram showing the direction of gravity from the front side to the back side of the paper.

[0088] The power generator may be covered with a cover 80 that covers the entire device to prevent the intrusion of dust, rain, etc. from the installation environment. In this case, the coil terminals may pass through the cover, or may be fitted inside the cover (plug-in type). Figure 8 shows an example of a power generator covered with a cover 80 that covers the entire device. Figure 8 shows an example in which the coil terminals 21 pass through the cover.

[0089] As described above, the power generating device of the present invention is a device that generates power by vibrating a soft magnetic member using a vibration source. Therefore, it is preferable to tune the resonant frequency of the soft magnetic member to the resonant frequency of the environment. Examples of ways to achieve this include devising the shape of the soft magnetic plate, adjusting the distance between the magnet and the soft magnetic plate, or placing a weight at the tip. Below, specific examples are given as more preferable ranges when using a rotating device, etc. The following are examples, and it goes without saying that the form of the device is not limited to these.

[0090] The resonance frequency and power generation performance when the shape of the soft magnetic member is changed will be described with reference to Figure 9. Grain-oriented electrical steel sheets were used as the soft magnetic members, and the shapes were adjusted by cutting, pressing, or grinding. The grain-oriented electrical steel sheets were processed to a length L of 55 mm, a width W of 10 mm, and a thickness t of 0.35 mm, and stress relief annealing was performed at 800°C for 2 hours. The longitudinal direction was the <001> orientation of the grain-oriented electrical steel sheets. The specific shapes were as shown in Figure 9 (a) to (e).

[0091] Table 1 shows the resonant frequency and generated voltage when the soft magnetic member was formed into each of the above shapes. To evaluate at the same acceleration, the generated voltage was divided by the acceleration. Shape (a) was rectangular and had a resonant frequency of 150 Hz. Shape (b) had zigzag grooves and a resonant frequency of 90 Hz. Shape (c) had fewer zigzag grooves than shape (b) and had a resonant frequency of 100 Hz. Shape (d) had a triangular shape tapered at the free end, and shape (e) had a triangular shape tapered at the fixed end. The resonant frequencies were 180 Hz and 130 Hz, respectively. To match the frequency present in the environment, it is preferable to set the resonant frequency to 150 Hz or less. For example, it is better to reduce the rigidity by processing shapes (b) and (c). Furthermore, by reducing the rigidity, a larger amplitude can be obtained even with the same acceleration, and therefore the generated voltage also increases. Therefore, the conditions may be changed as appropriate, taking into account the balance with the size of the magnet, etc.

[0092]

[0093] Next, referring to Figure 10, an example will be described in which the relationship between the gap between the soft magnetic member and the magnetic field source, the distance between the fixed end of the soft magnetic member and the magnetic field source, the weight of the weight placed on the tip of the soft magnetic member, and the resonant frequency was investigated.

[0094] In Fig. 10, a soft magnetic member 10, which is a grain-oriented electromagnetic steel plate, and a coil 20 arranged to be wound around the soft magnetic member 10 are fixed to a support 50. A magnetic field generating source 30, which is a magnet, is also fixed to the support 50. A weight 70 is provided near the tip of the soft magnetic member 10 as needed. There is a gap of length d [mm] between the free end 11, which is the tip of the soft magnetic member 10, and the magnetic field generating source 30. In Fig. 10, the distance between the fixed portion 12 of the soft magnetic member 10 and the magnetic field generating source 30 is D [mm]. In other words, the length from the free end 11 of the soft magnetic member 10 to the fixed portion 12 is D-d [mm].

[0095] The grain-oriented electromagnetic steel plate had a width (length perpendicular to the paper surface) of 10 mm and a thickness (length from top to bottom in Figure 10) of 0.35 mm. The length (length from left to right in Figure 10) was set to a length sufficient to ensure that the gap between the magnet and the soft magnetic plate and the distance between the fixed end of the soft magnetic member and the magnetic field generation source satisfied the following conditions, and that the soft magnetic member 10 could be fixed to the support 50. The coil 20 used was a linear coil with 0.1 mmφ wound 3,500 turns. The magnet used was a 412 mT magnet measuring 8 mm x 5 mm x 4 mm. The distance dcoil between the magnetic field generation source 30 and the coil 20 was fixed at 13 mm.

[0096] The resonance frequency when the gap d between the magnet and the soft magnetic plate is adjusted is shown in Table 2. A grain-oriented electromagnetic steel plate with the shape (55 x 10 x 0.35) shown in Figure 9(a) was used as the soft magnetic member, and the distance D from the fixed end to the magnet was fixed at 40 mm. No weight was used. In this case, the relationship between the gap d (mm) and the resonance frequency f (Hz) is as follows when d>0: f = 148.27 x d 0.3931 It was confirmed that the resonance frequency f increases as the gap d increases. This is thought to be because the length of the plate becomes shorter as the gap d increases. Assuming that the frequency range to be used is 150 Hz, it is preferable that the gap d at the tip be 1 mm or less.

[0097]

[0098] Next, Table 3 shows the resonance frequency when the distance D between the fixed end and the magnet is changed. The gap d was fixed at 1 mm. No weight was used. When the distance D (mm) is changed, the soft magnetic plate becomes longer, so the resonance frequency f (Hz) decreases, and when D > 0, f = 64726 × D -1.652 Assuming that the frequency range to be used is 150 Hz, it is preferable that the distance D is 40 mm or more.

[0099]

[0100] Next, Table 4 shows the resonance frequency when a weight 70 is placed on the tip. The gap d is 1 mm, and the distance D from the fixed end to the magnet is fixed at 40 mm. When a weight m (g) is placed on the tip, the resonance frequency f (Hz) decreases, and when m > 0, f = 68.598 × m―0.449 Assuming that the frequency range to be used is 150 Hz, it is preferable that the weight m be 0.18 g or more.

[0101]

[0102] The above-mentioned preferred range is an example when a grain-oriented electromagnetic steel sheet having a thickness of 0.35 mm is used, and may be changed as appropriate according to the material of the soft magnetic sheet to be used.

[0103] Second Embodiment Next, a second embodiment of the power generating device of the present invention will be described with reference to FIG.

[0104] FIG. 11 is a schematic diagram illustrating only the soft magnetic members and magnetic field generating sources of the power generating device of the present invention, and shows their positional relationship. As shown in FIG. 11( a), in the power generating device of the present invention, soft magnetic members 10 may be arranged on both sides of one magnetic field generating source 30, with the side closer to the magnetic field generating source 30 being the free end and the side farther away being the fixed portion. Alternatively, as shown in FIG. 11( b), a soft magnetic member 10 may be arranged between two magnetic field generating sources 30, with both ends of each soft magnetic member 10 closer to the magnetic field generating source 30 being the free ends and the center being the fixed portion. In the configurations of FIGS. 11( a) and 11(b), the magnetic field generating source 30 may be, for example, two permanent magnets, as described above. When two permanent magnets are used, the arrangement of the south and north poles is not limited. For example, as shown in FIG. 11( c), two magnets may be arranged with their south and north poles aligned vertically.

[0105] 11(d), the magnetic moments of the two permanent magnets may be arranged so that their south and north poles face in opposite directions, that is, so that the magnetic moments of the two permanent magnets face in parallel with the longitudinal direction of the soft magnetic member and perpendicular to the direction in which the free end of the soft magnetic member can move, with the magnetic moments of the two permanent magnets facing in opposite directions alternately. This increases the magnetic field strength.

[0106] Furthermore, when three or more permanent magnets are arranged, they may be arranged in a Halbach array as shown in Fig. 11(e). The Halbach array is an array in which the magnetic pole direction is optimized to maximize the magnetic field strength, thereby maximizing the magnetic field strength.

[0107] Third Embodiment Next, a third embodiment of the power generating device of the present invention will be described with reference to FIG.

[0108] As described above, the power generating device of the present invention generates power by vibrating a soft magnetic member using a vibration source. Therefore, the vibration from the vibration source must be transmitted to the soft magnetic member. If the vibration is transmitted to, for example, a fixed portion of the soft magnetic member or a coil support, the vibration energy transmitted to the soft magnetic member may decrease, resulting in a decrease in power generation efficiency. Therefore, it is preferable that the frequency at which the vibration spectrum of the soft magnetic member is maximized is in an appropriate frequency band.

[0109] Specifically, as shown in Fig. 12, the frequency at which the vibration spectrum of the soft magnetic member is maximized is preferably in a frequency band in which the vibration spectrum G(ω) of the fixed part, coil support, and magnetic field source support is equal to or less than half the maximum value of G(ω). By making the frequency at which the vibration spectrum of the soft magnetic member is maximized significantly deviate from the frequency band in which the vibration spectrum of the fixed part, etc. is maximized, vibration energy can be efficiently transmitted to the soft magnetic member, improving power generation efficiency.

[0110] Fourth Embodiment Next, a fourth embodiment of the power generating device of the present invention will be described with reference to FIG.

[0111] As described above, in the power generating device of the present invention, magnetic flux from the magnetic field generating source 30 penetrates the soft magnetic member 10, and the coil 20 is arranged so as to interlink with this magnetic flux, and power is generated by the vibration of the soft magnetic member. Due to the nature of magnetic flux, magnetic flux that starts from the magnetic field generating source 30 and penetrates the soft magnetic member 10 always returns to the magnetic field generating source 30. In this case, if the magnetic flux passes through the position of the soft magnetic member 10 where the coil 20 is wound in the opposite direction and returns, an electromotive force in the opposite direction will be generated, which may reduce the power generation efficiency. Therefore, when the magnetic flux returns to the magnetic field generating source 30, it is preferable that it returns by passing outside the coil 20.

[0112] In the fourth embodiment, to achieve such a flow of magnetic flux, the soft magnetic member is divided into a transmission section P2 where the coil is wound, an introduction section P1 that is closer to the magnetic field source than the transmission section, and a return section P3 that is farther from the magnetic field source than the transmission section. Let P1L be the average length and P1A be the average cross-sectional area of ​​the soft magnetic member in the introduction section, P2L be the average length and P2A be the average cross-sectional area of ​​the soft magnetic member in the transmission section, and P3L be the average length and P3A be the average cross-sectional area of ​​the soft magnetic member in the return section. The following relationship is satisfied: P1L / P1A≦P2L / P2A≦P3L / P3A. Here, the average length of the soft magnetic member refers to the average length of the portion through which magnetic flux passes, and the average cross-sectional area of ​​the soft magnetic member refers to the average cross-sectional area of ​​the soft magnetic member when cut perpendicular to the longitudinal direction.

[0113] Specifically, the shapes shown in Figures 13(a) to 13(d) are conceivable, but the specific shapes are not limited to these.

[0114] Fifth Embodiment Next, a fifth embodiment of the power generating device of the present invention will be described with reference to FIG.

[0115] Like the fourth embodiment, the fifth embodiment aims to allow the magnetic flux to return to the magnetic field generating source 30 by passing through the outside of the coil 20. Specifically, a magnetic flux feedback member 90 is provided that is connected to the side of the soft magnetic member farther from the magnetic field generating source and extends toward the magnetic field generating source. An example is shown in FIG. 14 . FIG. 14( a) is a top view showing a schematic diagram of a power generating device of the present invention. As shown in FIG. 14( a), the magnetic flux feedback member may be provided so that the magnetic flux passes outside the coil. FIG. 14( b) is a side view showing a schematic diagram of a power generating device of the present invention. As shown in FIG. 14( b), the magnetic flux feedback member 90 may be provided so that the magnetic flux passes above and below the coil. The magnetic flux feedback member 90 may be connected to the magnetic field generating source 30. The specific shape is not limited to this.

[0116] It is preferable that the shape of the magnetic flux feedback member 90 is approximately symmetrical with respect to the plane of symmetry, as shown in Fig. 15. In Fig. 15, (a) is a diagram showing the direction of gravity from the top to the bottom of the paper, and (b) is a diagram showing the direction of gravity from the front to the back of the paper.

[0117] Sixth Embodiment Next, a sixth embodiment of the power generating device of the present invention will be described with reference to FIG.

[0118] As described above, the power generating device of the present invention generates power by vibrating a soft magnetic member using a vibration source. Therefore, it is necessary to tune the resonant frequency of the soft magnetic member to the resonant frequency of the environment. A sixth embodiment of the power generating device includes two or more sets of soft magnetic members, coils, and magnetic field generating sources, with the soft magnetic members of each set connected together. An example is shown in FIG. 15 . In FIG. 16( a), two sets of soft magnetic members, coils, and magnetic field generating sources are connected together by soft magnetic members, which form a U-shape. This configuration allows vibrations from multiple frequencies to be absorbed and utilized for power generation, thereby improving power generation efficiency. Having two soft magnetic members with different lengths is preferable because it makes the resonant frequency more variable. FIG. 16( b) shows an example in which three sets of soft magnetic members, coils, and magnetic field generating sources are connected together by soft magnetic members.

[0119] Seventh Embodiment As described above, in the power generating device of the present invention, a weight (first weight) for adjusting vibration conditions may be disposed on the soft magnetic member. Furthermore, in addition to the first weight, a second weight and, if necessary, a third weight may be disposed at another position. The second weight may be disposed at a portion other than the free end of the soft magnetic member. Furthermore, in addition to the soft magnetic member, a weight may also be disposed on at least one of the magnetic field generating source and the magnetic field generating source support. By using multiple weights and adjusting them to change the vibration conditions, it is possible to find the optimal conditions for maximizing peak power generation.

[0120] Although several embodiments of the present invention have been described above, the specific configurations shown in the above embodiments are merely examples, and the technical scope of the present invention is not limited to these. Those skilled in the art may modify these embodiments as appropriate, and the technical scope of the present invention includes such modifications.

[0121] A power generating device was fabricated, including a soft magnetic member, a coil, and a magnetic field source, as shown in FIG. 1 . The soft magnetic member was a 50 x 8 mm rectangular grain-oriented silicon steel plate with a thickness of 0.35 mm. The coil was made of copper wire and positioned 10 to 23 mm from the tip of the grain-oriented silicon steel plate. A NdFe-based permanent magnet was used as the magnetic field source. The permanent magnet measured 4 mm high, 5 mm wide, and 8 mm deep, and was positioned so that its magnetic poles were aligned vertically, i.e., perpendicular to the surface of the grain-oriented silicon steel plate. The gap between the tip of the grain-oriented silicon steel plate and the permanent magnet was approximately 1 mm.

[0122] The tip of the soft magnetic member was then depressed approximately 2.5 mm from the basic position shown in Figure 5(b), followed by a plucking motion, and the output voltage was measured. The load resistance at this time was 2 kΩ. Figure 17 shows the voltage waveform across the load and the time change in the position of the tip of the soft magnetic member. The position of the lower basic position was set to 0 mm, and the plucking occurred at approximately 0.008 seconds in Figure 17. The peak voltage immediately after plucking was approximately 18 V. The voltage decayed to approximately 3 V after 0.08 seconds. Furthermore, for approximately 0.05 seconds after plucking, the soft magnetic member oscillated back and forth between the two basic positions, with the center of the amplitude being approximately 0.8 mm. After approximately 0.05 seconds, the soft magnetic member oscillated around one basic position, i.e., the 0 mm position. The decay pattern of the voltage waveform changed in response to the change in the position of the tip of the soft magnetic member.

[0123] In the power generating device according to the present embodiment described above, general-purpose soft magnetic materials can be used as the material for the soft magnetic members that are the subject of vibration, making it easy to manufacture and allowing for a wide range of material choices. Furthermore, a single permanent magnet functions as the magnetic field generating source, making it possible to manufacture the entire device inexpensively. Furthermore, the power generating device according to the present embodiment can utilize the high magnetic permeability characteristic of soft magnetic members, thereby increasing the change in magnetic flux passing through the coil. This allows for a large amount of power generation.

[0124] REFERENCE SIGNS LIST 1 power generating device 10 soft magnetic member 11 free end 12 fixed portion 20 coil 21 terminal 30 magnetic field generating source 50 support 51 screw 70 weight 80 cover 90 magnetic flux feedback member P1 introduction portion P2 transmission portion P3 feedback portion

Claims

1. A power generating device comprising a soft magnetic member, a coil, and a magnetic field generating source, wherein the soft magnetic member has a free end that is an end that can move in at least one direction, and a supported fixed part, the coil is wound around at least a portion of the soft magnetic member, and the magnetic field generating source is disposed on the opposite side of the soft magnetic member with respect to a plane that is perpendicular to the longitudinal direction of the soft magnetic member and that passes through the free end.

2. The power generating device according to claim 1, wherein the direction of the magnetic moment of said magnetic field generating source and the direction in which said free end can move are parallel.

3. A power generating device as described in claim 2, characterized in that when the free end of the soft magnetic member is stationary with no external mechanical force acting on the soft magnetic member, the magnetic field generating source is located on an extension line extending from the free end of the soft magnetic member in the longitudinal direction of the soft magnetic member.

4. The power generating device according to claim 1, wherein said magnetic field generating source is one or more permanent magnets.

5. The power generating device according to claim 4, wherein the permanent magnets are two or more and are united as one piece.

6. A power generating device according to claim 5, characterized in that the magnetic moments of the two or more permanent magnets are oriented parallel to the longitudinal direction of the soft magnetic member, perpendicular to the movable direction of the free end, and alternately in opposite directions.

7. The power generating device according to claim 5, wherein the magnetic moments of the two or more permanent magnets are oriented in a Halbach array.

8. The power generating device according to any one of claims 1 to 3, characterized in that the magnetic field generating source is fixed by a non-magnetic member.

9. The power generating device described in claim 1, characterized in that the frequency at which the vibration spectrum of the soft magnetic member is at its maximum is a frequency band at which the vibration spectrum G(ω) of the fixed part, the coil support member that supports the coil, and the magnetic field source support member that supports the magnetic field source is less than half the maximum value of G(ω).

10. The power generating device described in claim 1, characterized in that the soft magnetic member is divided into a transmission section P2, which is the section around which the coil is wound, an introduction section P1, which is closer to the magnetic field source than the transmission section, and a return section P3, which is farther from the magnetic field source than the transmission section, and when the average length of the soft magnetic member in the introduction section is P1L and the average cross-sectional area is P1A, the average length of the soft magnetic member in the transmission section is P2L and the average cross-sectional area is P2A, and the average length of the soft magnetic member in the return section is P3L and the average cross-sectional area is P3A, then P1L / P1A≦P2L / P2A≦P3L / P3A.

11. The power generating device according to claim 1, further comprising a magnetic flux return member connected to the side of the soft magnetic member farther from the magnetic field source and extending toward the magnetic field source.

12. The power generating device according to claim 1, comprising two or more sets of the soft magnetic member, the coil, and the magnetic field generating source, the soft magnetic members of each set being connected together.

13. The power generating device according to claim 1, wherein the soft magnetic member is provided with a first weight for adjusting vibration conditions.

14. The power generating device according to claim 13, wherein the first weight is disposed between the magnetic field generating source and the fixed portion.

15. The power generating device according to claim 13, wherein the first weight is disposed near the free end of the soft magnetic member.

16. A power generating device as described in claim 15, characterized in that one or more of the following is satisfied: [1] the distance between the soft magnetic member and the magnetic field generating source is 1 mm or less; [2] the length of the soft magnetic member is 40 mm or more; and [3] the weight applied to the tip is 0.18 g or more.

17. The power generating device according to claim 14, wherein the direction from the fixed portion toward the free end is parallel to the direction of gravity.

18. The power generating device according to claim 14, wherein the direction from the fixed portion toward the free end is perpendicular to the direction of gravity and parallel to the plate surface of the soft magnetic member.

19. The power generating device according to claim 14, wherein the soft magnetic member has one or more weights other than the first weight at a portion other than the free end.

20. The power generating device according to claim 19, characterized in that it comprises two or more weights other than the first weight.

21. The power generating device according to claim 14, wherein at least one of the magnetic field generating source and a magnetic field generating source support supporting the magnetic field generating source includes one or more weights other than the first weight.

22. A power generating device according to any one of claims 1 to 21, characterized in that the soft magnetic member is flat and the direction in which the free end can move is perpendicular to the plate surface of the soft magnetic member.

23. The power generating device according to claim 22, wherein the direction of the magnetic moment of the magnetic field generating source is perpendicular to the longitudinal direction of the soft magnetic member and to the plate surface of the soft magnetic member.

24. A power generating device described in any one of claims 1 to 21, characterized in that the area between the free end and the fixed part of the soft magnetic member is stable due to the magnetic field distribution generated by the magnetic field generating source in the absence of external mechanical force.

25. A power generating device as described in any one of claims 1 to 21, characterized in that there are multiple positions where the area between the free end and the fixed part of the soft magnetic member is stable in the absence of external mechanical force.

26. A power generating device according to any one of claims 1 to 21, characterized in that it comprises an external force applying mechanism for applying a mechanical external force to the soft magnetic member.

27. The power generating device according to claim 26, wherein a non-magnetic cover is attached to the soft magnetic member at a position where the external mechanical force is applied by the external force application mechanism.

28. A power generating device as described in any one of claims 1 to 21, characterized in that the inner diameter of the coil on the free end side of the soft magnetic member is larger than the inner diameter of the coil on the fixed portion side of the soft magnetic member.

29. A power generating device according to any one of claims 1 to 21, characterized in that it is provided with a capacitor.

30. The power generating device of claim 29, wherein the capacitor is connected in parallel with the coil.

31. A power generating device comprising a cover attached to cover the power generating device according to any one of claims 1 to 21, and terminals from the coil passing through the cover from the inside to the outside.

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