JP2015211626A - Magneto-striction type vibration power generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magneto-striction type vibration power generator capable of also improving power generation efficiency while preventing durability of a strength member from being reduced by stress concentration.SOLUTION: In a magneto-striction type vibration power generator 10, a power generation element formed from a magnetostrictive material is fitted in parallel to a long strength member 12 which is formed from a ferromagnetic material and of which one end is fixed to a vibration member 20, and a voltage is generated in a coil 40 on the basis of a cange in a magnetic permeability relative to a distortion of the power generation element 14. Flexure stiffness in a deformable part 28 of the strength member 12 arranged in parallel with the power generation element 14 is varied in a length direction of the strength member 12 and in the deformable part 28, and a portion with minimum flexure stiffness is eccentric closer to a free end of the strength member 12 than a center of the deformable part 28 in the length direction.

Description

  The present invention relates to a magnetostrictive vibration power generation apparatus that converts vibration energy into electric energy by utilizing a change in magnetic permeability with respect to strain of a power generation element formed of a magnetostrictive material.

  2. Description of the Related Art Conventionally, there is a magnetostrictive vibration power generation apparatus using a power generation element formed of a magnetostrictive material as a type of vibration power generation apparatus that converts vibration energy into electric energy. For example, in the magnetostrictive vibration power generation device disclosed in Japanese Patent No. 4905820 (Patent Document 1), a strength member (11b) formed of a ferromagnetic material and a power generation element (11a) formed of a magnetostrictive material are arranged in parallel. In addition, a bias magnetic field generated by the magnet (14) is applied to the power generation element, and the coil (12) is wound around a closed magnetic path including the power generation element. In addition, when vibration is input, distortion in the length direction is input to the power generation element due to deformation of the strength member, so that the magnetic permeability of the power generation element changes and a voltage due to electromagnetic induction is generated in the coil. Yes.

  By the way, in order to improve the power generation efficiency in the magnetostrictive vibration power generation apparatus, it is desirable to appropriately control the deformation of the strength member and distribute the uniform stress over the entire power generation element. This is because the permeability of the power generating element does not change linearly with respect to the strain, and the rate of change decreases as the strain increases. Specifically, the stress exerted on the power generating element can be dispersed by causing the stress exerted on the strength member at the time of vibration input to act in a dispersed manner without being concentrated.

  However, in the structure of Patent Document 1, when vibration is input in a state where one end of the strength member is attached to the vibration member and one end support is attached, a large moment acts on the power generating element as it goes to the fixed end side of the strength member. Therefore, the distortion of the power generation element is difficult to be uniform, and it is difficult to improve the power generation efficiency. A similar problem may occur even in a structure in which the strength member and the connecting yoke (10a, 10b) are integrated.

Japanese Patent No. 4905820

  The present invention has been made in the background of the above-described circumstances, and its solution is to prevent magnetostriction of a novel structure that can improve power generation efficiency while preventing deterioration of durability of the strength member due to stress concentration. An object of the present invention is to provide a vibration generator.

  Hereinafter, the aspect of this invention made | formed in order to solve such a subject is described. In addition, the component employ | adopted in each aspect as described below is employable by arbitrary combinations as much as possible.

That is, according to the first aspect of the present invention, a power generation element formed of a magnetostrictive material is attached in parallel to a longitudinal strength member formed of a ferromagnetic material and fixed at one end to the vibration member. A magnet for applying a bias magnetic field to the power generation element is provided, and a coil is wound around a closed magnetic path including the power generation element, and the change in permeability with respect to distortion of the power generation element In the magnetostrictive vibration power generator configured to generate a voltage in the coil based on
The bending rigidity in the deformed portion of the strength member arranged in parallel with the power generating element is changed in the length direction of the strength member, and the portion where the bending rigidity in the deformed portion is minimized is the deformation portion. It is characterized by being biased toward the free end side of the strength member from the center in the length direction.

  According to the magnetostrictive vibration power generator configured as described above according to the first aspect, when a vibration load is input, a bending moment is applied to the strength member attached to the vibration member with a cantilever structure. Since it acts so that it becomes large as it goes to, large stress tends to act on the fixed end side. Here, since the portion where the bending rigidity in the deformed portion is minimized is biased toward the free end side of the strength member, the deformed portion is distributed and stressed over a wide range in the length direction. As a result, the durability of the power generating element is improved and the power generating element arranged in parallel with the deformed portion is dispersed and stressed in the length direction. Improvement is realized.

  According to a second aspect of the present invention, in the magnetostrictive vibration power generating device described in the first aspect, the portion of the strength member where the bending rigidity in the deformed portion is minimized is linear in the width direction of the strength member. It is what extends.

  According to the second aspect, since the portion where the bending rigidity in the deformed portion is minimized extends linearly in the width direction of the strength member, the bending deformation of the deformed portion is efficient in the minimum portion of the bending rigidity. Therefore, the power generation element is efficiently distorted in the length direction, and the power generation efficiency is improved.

  According to a third aspect of the present invention, in the magnetostrictive vibration power generator described in the first or second aspect, the free end side is longer than the fixed end side than the deformed portion of the strength member. It is.

  According to the third aspect, since the free end side is longer than the fixed end side of the deformable portion of the strength member that functions as a mass at the time of vibration input, the elastic deformation of the deformable portion at the time of vibration input. The amount is increased and the distortion of the power generation element is increased. Therefore, a large change in the magnetic permeability due to the inverse magnetostriction effect of the power generation element occurs, and excellent power generation efficiency is realized.

  According to a fourth aspect of the present invention, in the magnetostrictive vibration power generation device described in any one of the first to third aspects, the bending rigidity of the power generation element is made smaller than the minimum bending rigidity of the deformable portion. It is what.

  According to the 4th aspect, the neutral axis | shaft about the deformation | transformation part of the intensity | strength member arranged in parallel and the bending deformation of an electric power generation element is biased and set to the deformation | transformation part side. Therefore, the distortion in the length direction of the power generation element is efficiently generated with respect to the bending deformation of the deformation portion, and the power generation efficiency is improved by the inverse magnetostriction effect.

  According to a fifth aspect of the present invention, in the magnetostrictive vibration power generation device according to any one of the first to fourth aspects, the strength member has a groove extending in the middle in the length direction over the entire length in the width direction. The power generating element is disposed across the concave groove, and a portion where the concave groove is formed in the strength member is the deformed portion.

  According to the fifth aspect, since the bending strength is changed by forming the concave groove and the bending rigidity is reduced, the deformation of the strength member due to vibration input is a deformation portion of the concave groove. It is possible to advantageously cause distortion in the length direction in the power generating element that is intensively generated in the portion and disposed across the concave groove. In addition, if the groove is formed in the strength member extending with a substantially constant cross-sectional shape, a deformed portion having a small bending rigidity can be easily set in the portion where the groove is formed. By setting the main vibration input direction to the depth direction of the concave groove, it becomes easy to set the bending rigidity of the strength member small, and the power generation efficiency is advantageously improved by obtaining a large distortion of the power generation element. .

  According to a sixth aspect of the present invention, in the magnetostrictive vibration power generation device described in the fifth aspect, the intermediate portion of the concave groove in the length direction of the strength member has a deepest portion having a maximum depth. The bending strength of the strength member is minimized at the deepest portion, and the concave groove is formed on the inner surface of the bottom wall of the concave groove from the deepest portion to the outside in the length direction of the strength member. An inclined bottom surface that is inclined toward the opening side is provided.

  According to the sixth aspect, the bending rigidity of the deformed portion can be easily minimized at the deepest portion where the depth of the concave groove is maximized and the bending rigidity can be easily set small. Moreover, the inner surface of the bottom wall of the concave groove is composed of inclined bottom surfaces on both sides of the deepest part, so that the cross-sectional shape of the deformed part gradually changes toward the deepest part, and stress concentration due to a sudden change in the cross-sectional shape. Is also eased.

  According to a seventh aspect of the present invention, in the magnetostrictive vibration power generation device according to the fifth or sixth aspect, the inner surface of the bottom wall of the concave groove is concave on the opening side curved in the length direction of the strength member. It is a curved surface.

  According to the seventh aspect, when vibration is input in the depth direction of the groove and the strength member is bent and deformed by the deformed portion, the stress concentration is caused by the inner surface of the bottom wall of the groove being a curved surface. Is prevented, and the durability of the strength member is improved.

  According to an eighth aspect of the present invention, in the magnetostrictive vibration power generator described in any one of the fifth to seventh aspects, the inner surface of the opening edge of the concave groove is a convex R surface. It is.

  According to the eighth aspect, when the power generating element is bent and deformed by the shape of the inner surface of the opening edge of the concave groove expanding toward the opening side, the inner surface of the opening edge of the concave groove This prevents the power generating element from being damaged. Moreover, since the inner surface of the opening edge of the groove is a convex R surface, the inner surface of the opening edge of the groove forms a step or a broken line with respect to the surface of the strength member where the groove is opened. It is provided smoothly and continuously, and stress concentration is prevented at the contact portion between the power generation element and the strength member at the time of vibration input, thereby improving durability.

  According to the present invention, the strength member includes the deforming portion in which the power generation elements are arranged in parallel, and the bending rigidity of the deforming portion changes in the length direction, and the bending rigidity in the deforming portion is minimized. However, it is arranged so as to be shifted to the free end side of the strength member from the longitudinal center of the deformable portion. As a result, the deformation center of the deforming portion due to vibration input is set so as to deviate toward the free end, and the bending moment acting on the deforming portion is further averaged in the length direction. As a result, the durability is improved by the stress dispersion in the deformed portion of the strength member, and the stress is also distributed in the length direction to the power generating element arranged in parallel with the deformed portion, so that the durability and power generation are improved. Increased efficiency is realized.

1 is a perspective view showing a magnetostrictive vibration power generation apparatus as a first embodiment of the present invention. FIG. 2 is a plan view of the magnetostrictive vibration power generator shown in FIG. 1. III-III sectional drawing of FIG. The perspective view of the intensity | strength member which comprises the magnetostrictive vibration electric power generating apparatus shown in FIG. The longitudinal cross-sectional view which expands and shows the principal part of the intensity | strength member shown in FIG. FIG. 2 is a stress distribution diagram in a state in which a bending load is applied to a strength member and a power generation element that constitute the magnetostrictive vibration power generation device illustrated in FIG. 1. The stress distribution figure of the state which added the bending load to the intensity | strength member and electric power generating element which comprise the magnetostrictive vibration electric power generating apparatus of the conventional structure. The perspective view of the intensity | strength member which comprises the magnetostrictive vibration electric power generating apparatus as 2nd embodiment of this invention. The longitudinal cross-sectional view which expands and shows the principal part of the intensity | strength member shown in FIG. The longitudinal cross-sectional view which expands and shows the principal part of the intensity | strength member which comprises the magnetostrictive vibration electric power generating apparatus as 3rd embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  1 to 3 show a magnetostrictive vibration power generation apparatus (hereinafter referred to as vibration power generation apparatus) 10 as a first embodiment of the present invention. The vibration power generation apparatus 10 has a structure in which a power generation element 14 is attached to a longitudinal strength member 12. In the following description, in principle, the length direction is the left-right direction in FIG. 2, which is the left-right direction, the width direction is the up-down direction in FIG. 2, which is the front-rear direction, and the thickness direction is the up-down direction. The vertical directions in FIG.

  More specifically, as shown in FIG. 4, the strength member 12 is substantially formed of a ferromagnetic material such as stainless steel (such as martensitic stainless steel, ferritic stainless steel, precipitation hardening stainless steel) or iron. It is a rectangular rod-shaped member, and an attachment hole 16 penetrating in the thickness direction is formed at one end portion in the length direction (left end portion in FIG. 2). Then, as shown by a two-dot chain line in FIG. 3, when the mounting bolt 18 inserted through the mounting hole 16 of the strength member 12 is screwed to the vibration member 20, one end in the length direction of the strength member 12 is obtained. The portion is fixed to the vibration member 20. In addition, in the mounting state on the vibration member 20, the strength member 12 has one end (left end in FIG. 2) as a fixed end fixed to the vibration member 20, and the other end (right end in FIG. 2) is free. It is considered as an end.

  Further, as shown in FIGS. 3 and 5, a concave groove 22 that opens toward one side in the thickness direction (upward in FIG. 3) is formed in the intermediate portion in the length direction of the strength member 12. The concave groove 22 is formed at a position shifted from the center to the fixed end side (left side in FIG. 3) in the length direction of the strength member 12, and is substantially constant over the entire length of the strength member 12 in the width direction. The cross-sectional shape extends continuously. By forming such a concave groove 22, the strength member 12 includes an attachment portion 24 positioned on the fixed end side with respect to the concave groove 22, and a mass portion 26 positioned on the free end side with respect to the concave groove 22. The bottom wall portion of the concave groove 22 and the deformation portion 28 that connects the attachment portion 24 and the mass portion 26 to each other are integrally provided. In addition, since the concave groove 22 is located on the fixed end side with respect to the center in the length direction of the strength member 12, the mass portion 26 is longer than the attachment portion 24. Further, screw holes 30 penetrating vertically in the thickness direction are formed on both sides of the strength member 12 with respect to the concave groove 22 in the length direction.

  Further, a deepest portion 32 that extends linearly in the width direction of the strength member 12 is set at an intermediate portion of the concave groove 22 in the length direction of the strength member 12, and the bottom wall inner surface extends from the deepest portion 32 to the strength member 12. Are provided with inclined bottom surfaces 34a, 34b that gradually incline upward toward the opening as they go outward in the length direction. In other words, the inclined bottom surface 34a, 34b is provided smoothly and continuously on the inner surface of the bottom wall of the concave groove 22, and the depth of the concave groove 22 is maximized at the boundary between the inclined bottom surface 34a, 34b. The deepest part 32 is set. In the present embodiment, the inclined bottom surfaces 34a and 34b are curved surfaces that are concave upward, and the entire inner surface of the bottom wall of the concave groove 22 is formed of a continuous curved surface that is concave upward. Is gradually changed in the length direction of the strength member 12. The strength member 12 of the present embodiment has a front-rear width dimension that is substantially constant over the entire length including the deformed portion 28, and a lower surface (the lower surface in FIG. 3) is a flat surface. The bending rigidity in the thickness direction is minimum at the deepest portion 32 where the thinnest portion 28 is provided.

  Furthermore, the inner surfaces of the pair of side walls of the concave groove 22 are flat surfaces that extend substantially perpendicular to the length direction of the strength member 12, and the upper end portion is directed toward the opening side (upper side in FIG. 3). The strength member 12 is gradually inclined outward in the length direction. In this embodiment, the inner surface of the opening edge of the concave groove 22 has an arcuate cross-sectional R surface 36 that is convex toward the opening side and the inner side of the groove. It is said that. The inner surfaces of the pair of side walls of the concave groove 22 are smoothly continuous with one of the inclined bottom surfaces 34 a and 34 b of the concave groove 22, and the entire inner surface of the concave groove 22 is broken in the length direction of the strength member 12. It consists of a continuous surface with no steps.

  The power generation element 14 is a long plate-shaped member formed of a magnetostrictive material and extending in a substantially constant rectangular cross section, and both end portions are superimposed on the upper surface of the strength member 12 and screwed into the screw hole 30. It is fixed to the strength member 12 by 38. As a result, the power generation element 14 extends across the opening of the concave groove 22 in the length direction of the strength member 12, and is arranged in parallel with the deformed portion 28 of the strength member 12 so as to be vertically separated.

  The magnetostrictive material used as the material for forming the power generation element 14 is not particularly limited, but iron-gallium alloy, iron-nickel alloy, iron-cobalt alloy, and the like are preferably employed. It can also be used in combination. In addition, the magnetostrictive material forming the power generation element 14 includes at least one kind of rare earth elements such as yttrium (Y) and praseodymium (Pr), thereby obtaining a large change in magnetic permeability of the power generation element 14 described later. You can also. Further, preferably, the bending rigidity of the power generation element 14 is made smaller than the minimum bending rigidity in the deformation portion 28 of the strength member 12, and the power generation element 14 is more likely to bend and deform than the strength member 12.

  A coil 40 is attached to the power generation element 14. The coil 40 is formed of a conductive metal wire wound around the power generation element 14, and an induced electromotive force is generated in the coil 40 by electromagnetic induction according to a change in magnetic flux of the power generation element 14. Further, the coil 40 enters the concave groove 22 of the strength member 12 when the power generating element 14 is attached to the strength member 12, and interference between the coil 40 and the strength member 12 is avoided. In addition, although it is not clear in the drawing, both ends of the metal wire constituting the coil 40 are electrically connected to a storage battery or an electric device (such as an LED or an electronic circuit).

  Magnets 42a and 42b are disposed on both sides of the strength member 12 in the front-rear direction. As the magnet 42, various known permanent magnets such as a ferrite magnet, an alnico magnet, and a neodymium magnet are employed, and are magnetized in the front-rear direction of the strength member 12. The magnet 42 a is fixed to the side surface of the mounting portion 24 in the strength member 12, and the magnet 42 b is fixed to the side surface of the mass portion 26 in the strength member 12. Further, the magnet 42a and the magnet 42b are magnetized in opposite directions. For example, when the strength member 12 side of the magnet 42a is an N pole, the strength member 12 side of the magnet 42b is an S pole. Furthermore, the pair of magnets 42a and 42a are fixed to the strength member 12 at substantially the same position in the length direction from one side of the front and rear, and the pair of magnets 42b and 42b are provided with the strength member 12. On the other hand, at substantially the same position in the length direction, they are fixed from one side of the front and rear. The means for fixing the magnet 42 to the strength member 12 is not particularly limited. For example, the magnet 42 may be realized by a magnetic attraction, adhesive, mechanical locking, or the like of the magnet 42.

  Furthermore, yoke members 44 are arranged in parallel on the front and rear sides of the strength member 12. The yoke member 44 has a rod shape or a longitudinal plate shape extending substantially parallel to the strength member 12, and is formed of a ferromagnetic material such as stainless steel or iron, like the strength member 12. The yoke member 44 extends over the magnet 42a and the magnet 42b, and has one end overlapped and fixed to the front and rear outer surfaces of the magnet 42a, and the other end to the front and rear outer surfaces of the magnet 42b. It is overlapped and fixed. The means for fixing the yoke member 44 to the magnet 42 is not particularly limited, and may be realized by, for example, magnetic attraction, adhesive, mechanical locking, or the like of the magnet 42.

  In this manner, the front and rear set of magnets 42a and 42b and the front and rear set of yoke member 44 are attached to both side surfaces of the strength member 12, whereby the strength member 12, the power generating element 14, the magnets 42a and 42b, and the yoke. A closed magnetic path 46 is formed by the member 44. A bias magnetic field from the magnets 42 a and 42 b is applied to the power generation element 14 constituting the closed magnetic path 46. The coil 40 is disposed on the closed magnetic path 46 by being wound around the power generation element 14.

  When the vibration power generation apparatus 10 having such a structure is attached to the vibration member 20 shown in FIG. 3, when vertical vibration is input to the strength member 12, the concave groove 22 that is thin in the vertical direction. The strength member 12 is elastically deformed at the formation portion (deformation portion 28). Thereby, a stress in the compression / tensile direction is efficiently generated with respect to the power generation element 14, and the magnetic permeability of the power generation element 14 formed of a magnetostrictive material becomes an inverse magnetostriction effect (an effect of changing the magnetic permeability due to strain). ). As a result, since the magnetic flux penetrating the coil 40 changes, a voltage (inductive electromotive force) due to electromagnetic induction is generated in the coil 40 and used for charging a storage battery connected to the coil 40 or operating an electrical device. .

  Here, in the present embodiment, the front-rear width dimension of the strength member 12 is substantially constant, the inner surface of the bottom wall of the concave groove 22 is a curved surface, and the thickness dimension of the deformed portion 28 is the length of the strength member 12. Since it changes in the vertical direction, the bending rigidity of the deformable portion 28 changes in the length direction of the strength member 12. Further, the deepest portion 32 of the concave groove 22 is provided so as to be shifted to the free end side of the strength member 12 with respect to the center (A in FIG. 5) of the concave groove 22 in the length direction of the strength member 12 (FIG. 5), the deepest portion 32 having the thinnest thickness and the minimum bending rigidity in the deformed portion 28 is arranged so as to be biased toward the free end of the strength member 12 with respect to the center of the concave groove 22. As a result, the bending moment acting on the deformable portion 28 is further averaged in the length direction, and in the deformable portion 28 extending in parallel with the power generation element 14, stress is dispersed in the length direction, and the deformable portion 28 Durability is improved.

  Further, since the stress is dispersed in the deformed portion 28, the stress exerted on the power generating element 14 is also distributed in a wider range in the length direction, and therefore, distortion is generated in the wide range of the power generating element 14 on the average. As a result, the durability of the power generation element 14 and the power generation efficiency are improved as compared with the case where a large strain is locally generated. The power generation amount of the power generation element 14 corresponds non-linearly to the strain amount of the power generation element 14, and as the strain amount of the power generation element 14 increases, the rate of change of the power generation amount with respect to the change in strain decreases. Because.

  Note that how much the deepest portion 32 is biased in the length direction of the strength member 12 from the center of the concave groove 22 depends on the difference in length between the mounting portion 24 and the mass portion 26 in the strength member 12 or the deformation of the strength member 12. It is set according to the difference in bending rigidity between the portion 28 and the power generation element 14.

  It has been confirmed by simulation that the stress acting on the strength member 12 and the power generation element 14 is more dispersed than in the conventional structure in the structure of this embodiment. That is, as shown in FIG. 6, in the structure (example) of the present embodiment, a relatively small stress is exerted over a wide range on the bottom wall portion of the concave groove 22 in the strength member 12. In addition, sufficient durability is ensured, and stress is effectively applied to the entire power generation element 14, so that it is predicted that excellent power generation efficiency will be realized. On the other hand, as shown in FIG. 7, in the conventional structure (comparative example) in which the rectangular groove-shaped concave grooves are provided in the strength member, the corners at both ends in the length direction with respect to the bottom wall portion of the concave groove 102 in the strength member 100. The stress is concentrated on the portion, and the adverse effect on the durability of the strength member 100 becomes a problem, and the stress exerted on the end portion of the power generation element 104 fixed to the free end side of the strength member 100 is remarkably reduced. A decrease in power generation efficiency is expected.

  In addition, inclined bottom surfaces 34a and 34b are set on the inner surface of the bottom wall of the concave groove 22 in the strength member 12 of the present embodiment. 34a and 34b are concave curved surfaces, respectively, and the inclined bottom surfaces 34a and 34b are smoothly connected to each other with a common tangent line. Thereby, when the deformed portion 28 which is the bottom wall portion of the concave groove 22 is deformed in the thickness direction by vibration input, stress concentration due to a sudden change in the cross-sectional shape is prevented, and the durability of the strength member 12 is improved. Is planned.

  Further, in the strength member 12 of the present embodiment, the deepest portion 32 of the concave groove 22 set at the boundary between the inclined bottom surfaces 34 a and 34 b extends linearly in the width direction of the strength member 12. As a result, the strength member 12 is efficiently bent and deformed at the thinnest portion at the time of vibration input, and distortion of the power generation element 14 is effectively generated. Therefore, a change in magnetic permeability in the power generation element 14 is advantageously caused. As a result, the power generation efficiency is improved.

  Further, the concave groove 22 is formed at a position shifted from the center in the length direction of the strength member 12 toward the fixed end, and the mass portion 26 of the strength member 12 is longer than the attachment portion 24. Thereby, the mass of the mass portion 26 in the strength member 12 is set to be large, and the deformation of the strength member 12 is efficiently generated, so that the power generation efficiency is improved.

  Further, since the inner surface of the opening edge of the concave groove 22 is gradually expanded toward the opening side, the power generating element 14 interferes with the opening edge of the concave groove 22 when the strength member 12 and the power generating element 14 are deformed. This can prevent the generation element 14 from being deformed efficiently. Furthermore, since the inner surface of the opening edge of the groove 22 is a convex R surface 36, the inner surface of the opening edge of the groove 22 can be provided smoothly and continuously with the upper surface of the strength member 12, Even if the power generation element 14 is pressed against the boundary portion between the inner surface of the opening edge of the groove 22 and the upper surface of the strength member 12, it is possible to avoid intensive stress acting on the power generation element 14.

  Further, since the bending rigidity of the power generation element 14 is made smaller than the minimum bending rigidity of the deformation portion 28 in the strength member 12, the power generation element 14 is more easily deformed than the deformation portion 28. In contrast, the power generation element 14 is sufficiently distorted, and the power generation efficiency of the power generation element 14 can be increased. That is, since the neutral axis in bending deformation is set so as to be biased toward the strength member 12 relative to the power generation element 14, the influence of the strength member 12 is dominant on the bending deformation characteristics, and the compression / tensile stress on the power generation element 14 is determined. Will be generated more efficiently.

  FIG. 8 shows a strength member 50 constituting a magnetostrictive vibration power generation apparatus as a second embodiment of the present invention. Note that the power generation element 14, the pair of magnets 42 a and 42 b, and the pair of yoke members 44 that are omitted in FIG. 8 can all be the same as those in the first embodiment. Further, in the following description, members and portions that are substantially the same as those in the first embodiment are denoted by the same reference numerals in the drawings, and the description thereof is omitted.

  That is, as shown in FIGS. 8 and 9, the strength member 50 includes a concave groove 52 in the intermediate portion. The concave groove 52 is provided at a position biased to the fixed end side in the length direction of the strength member 50, opens in one direction in the thickness direction (upward in FIG. 9), and extends in the width direction of the strength member 50. Extending continuously. Further, the inner surface of the bottom wall of the concave groove 52 includes inclined bottom surfaces 54a and 54b. The inclined bottom surfaces 54a and 54b are inclined planes that gradually incline upward from the deepest portion 32 of the concave groove 52 in the length direction of the strength member 50, and are formed in a substantially valley-shaped broken line. It is continuous. The deepest portion 32 linearly extending in the width direction of the strength member 50 is formed by the boundary portion between the inclined bottom surfaces 54a and 54b.

  Further, as in the first embodiment, the deepest portion 32 of the concave groove 52 is on the free end side in the length direction of the strength member 50 with respect to the center of the concave groove 52 (one-dot chain line A in FIG. 9). It is positioned so as to be shifted. As a result, the stress exerted on the deformed portion 28 of the strength member 50 can be dispersed, the durability of the strength member 50 and the power generation element 14 can be improved, and the power generation efficiency can be improved by dispersing the distortion of the power generation element 14. Is planned. Note that a one-dot chain line B in FIG. 9 indicates the position of the deepest portion 32.

  FIG. 10 is an enlarged view of a main part of a strength member 60 constituting a magnetostrictive vibration power generation apparatus as a third embodiment of the present invention. The strength member 60 of the present embodiment is formed with a concave groove 62 that opens on the upper surface and extends the entire length in the width direction. Although not necessarily clear in the drawing, the concave groove 62 is formed at a position shifted to the fixed end side of the strength member 60 as in the first and second embodiments.

  The concave groove 62 is formed with a connection bottom surface 64 that extends substantially perpendicular to the thickness direction of the strength member 60 (vertical direction in FIG. 10) between the inclined bottom surfaces 34a and 34b, and the deepest portion 32 has a strength. The member 60 is provided with a predetermined width in the length direction. The connection bottom surface 64 extends in the common tangential direction of the inclined bottom surfaces 34a and 34b, and the connection bottom surface 64 and the inclined bottom surfaces 34a and 34b are smoothly continuous without breaks. The center of the deepest portion 32 (the chain line B in FIG. 10) is located on the free end side of the strength member 60 with respect to the center of the concave groove 62 (the chain line A in FIG. 10).

In the present embodiment, the thickness dimension (t ₁ ) of the end portion on the fixed end side of the deformable portion 28 is set larger than the thickness dimension (t ₂ ) of the end portion on the free end side of the deformable portion 28. ing. As a result, the durability of the deformable portion 28 is advantageously ensured at the end portion on the fixed end side of the deformable portion 28 where the bending moment acting upon vibration input is likely to increase.

  Even when the strength member 60 having such a structure according to the present embodiment is employed, durability and power generation efficiency can be improved by distributing the stress as in the first and second embodiments. In particular, by providing the connection bottom surface 64 and the inclined bottom surfaces 34a and 34b smoothly and continuously, it is possible to prevent stress concentration from occurring at the connection portion between the connection bottom surface 64 and the inclined bottom surfaces 34a and 34b.

  As mentioned above, although embodiment of this invention was explained in full detail, this invention is not limited by the specific description. For example, in the above-described embodiment, the structure in which the magnets 42a and 42b and the yoke member 44 are provided on both the front and rear sides of the strength member 12 is illustrated. However, the magnets 42a and 42b and the yoke member 44 may be only one of the front and rear. good. Furthermore, only one of the magnet 42a and the magnet 42b may be used. Furthermore, for example, a magnet can be disposed between the strength member and the power generation element, in which case the yoke member may be unnecessary.

  Moreover, the coil 40 should just be on the closed magnetic circuit 46, for example, the one coil 40 is wound by both the power generation element 14 and the deformation | transformation part 28 which were distribute | arranged in parallel, these power generation element 14 and a deformation | transformation part. 28 may be inserted into the coil 40.

  Moreover, in the said embodiment, the bending rigidity of the deformation | transformation part 28 is changed to the length direction by changing the depth dimension of the ditch | groove 22 in the length direction of the strength member 12, However, The width dimension of a deformation | transformation part is changed. By changing, the bending rigidity of the deformed portion can be changed.

  The deformation portion 28 of the strength member 12 may be any member that generates stress in the power generation element 14 due to deformation during vibration input. For example, the deformation portion 28 may be inclined with respect to the power generation element 14. The lengthwise dimension may be different.

  Further, the fixing method of the power generation element 14 to the strength member 12 is not limited to screwing, and adhesion such as using an adhesive or sandwiching the power generation element 14 between another member and the strength member 12 is possible. A method may also be employed.

  Further, the attachment structure of the strength member 12 to the vibration member 20 is not particularly limited to the bolt fixing exemplified in the embodiment.

10: Magnetostrictive vibration power generator, 12, 50, 60: Strength member, 14: Power generation element, 20: Vibration member, 22, 52, 62: Concave groove, 28: Deformation part, 32: Deepest part, 34, 54: Inclined bottom surface, 36: R surface, 40: coil, 42: magnet, 46: closed magnetic circuit

Claims (8)

A longitudinal strength member made of a ferromagnetic material and fixed at one end to the vibration member is attached in parallel with a power generation element formed of a magnetostrictive material, and a magnet for applying a bias magnetic field to the power generation element is provided. And a coil is wound around a closed magnetic path including the power generation element so that a voltage is generated in the coil based on a change in permeability with respect to distortion of the power generation element. In the magnetostrictive vibration power generator
The bending rigidity in the deformed portion of the strength member arranged in parallel with the power generating element is changed in the length direction of the strength member, and the portion where the bending rigidity in the deformed portion is minimized is the deformation portion. A magnetostrictive vibration power generator characterized by being biased toward the free end side of the strength member from the center in the length direction.   The magnetostrictive vibration power generator according to claim 1, wherein a portion of the strength member where the bending rigidity of the deformed portion is minimized extends linearly in the width direction of the strength member.   The magnetostrictive vibration power generator according to claim 1 or 2, wherein a free end side of the strength member is longer than a fixed end side of the deformable portion.   The magnetostrictive vibration power generator according to any one of claims 1 to 3, wherein a bending rigidity of the power generation element is smaller than a minimum bending rigidity of the deformable portion.   The strength member is formed with a groove extending in the middle in the length direction over the entire length in the width direction, and the power generating element is disposed across the groove to form the groove in the strength member. The magnetostrictive vibration power generator according to any one of claims 1 to 4, wherein the portion is the deforming portion.   An intermediate portion of the concave groove in the length direction of the strength member has a deepest portion having a maximum depth, and the bending rigidity of the strength member is minimized at the deepest portion, and the concave portion The magnetostrictive vibration power generator according to claim 5, wherein an inclined bottom surface is provided on the inner surface of the bottom wall of the groove so as to incline toward the opening side of the recessed groove as it goes outward in the length direction of the strength member from the deepest portion. .   The magnetostrictive vibration power generator according to claim 5 or 6, wherein the inner surface of the bottom wall of the concave groove is a concave curved surface on the opening side curved in the length direction of the strength member.   The magnetostrictive vibration power generator according to any one of claims 5 to 7, wherein an inner surface of the opening edge of the groove is a convex R surface.