Magnetostrictive power generation element

Abstract

To provide a magnetostriction power generation element enabling the power generation amount thereof to be increased.SOLUTION: A magnetostriction power generation element 1 comprises: a magnetostrictive body unit 2 having, in at least a portion thereof, a magnetostrictive body; a magnet providing a magnetic bias to the magnetostrictive body; a coil; and a bobbin 5 having a hollow portion 5b and storing at least a portion of the magnetostrictive body in the hollow portion 5b. The bobbin 5 has a wound portion 5c around which a coil is wound, on the outer circumferential side of the portion where the hollow portion 5b is arranged.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a magnetostrictive power generating element. [Background technology]

[0002] It has been known for some time that a magnetostrictive element is used as a power generating element. For example, Patent Document 1 discloses a magnetostrictive power generating element that includes a U-shaped frame (referred to in the document as a frame yoke), a magnetostrictive body (referred to in the document as a magnetostrictive plate) attached to the frame, and a coil wound around the frame and the magnetostrictive body.

[0003] Specifically, the magnetostrictive power generating element of Patent Document 1 includes a component at the tip of the frame, such as a weight, that can adjust the resonant frequency during vibration. When an external force is applied to this magnetostrictive power generating element, causing vibration, the weight vibrates up and down, bending the base (bottom of the U) of the U-shaped frame on which the magnetostrictive body is mounted. At the same time, the amplitude of the vibration at the tip of the frame increases, changing the surrounding magnetic field. This changed magnetic field induces a current in the coil, generating electricity. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-78237 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the magnetostrictive power generation element of Patent Document 1, for example, an air-core coil using a self-bonding wire is inserted on the frame and magnetostrictive body, and these are fixed with an adhesive. In this case, there is room for improvement in terms of power generation amount.

[0006] Specifically, there is room for improvement in increasing the amount of power generated by not directly arranging the coil around the frame and magnetostrictive body, and thereby not inhibiting the vibration (amplitude) of the frame and magnetostrictive body. The present invention has been made in view of the above circumstances, and provides a magnetostrictive power generating element that can increase the amount of power generated. [Means for solving the problem]

[0007] The magnetostrictive power generating element according to the present invention includes a magnetostrictive body unit having a magnetostrictive body at least in a portion thereof, a magnet that applies a magnetic bias to the magnetostrictive body, a coil, and a bobbin having a hollow portion and accommodating at least a portion of the magnetostrictive body in the hollow portion, the bobbin having a wound portion around which the coil is wound, on the outer circumferential side of the hollow portion. The magnetostrictive unit is formed in a U-shape in a side view, and includes a first piece including a base end portion, a second piece including a flexible portion and located on the return side, around which the wound portion is disposed, and a folded-back portion connected to the first piece and the second piece. The bobbin has flanges on both ends of the wound portion, the second piece is passed through the hollow portion, and at least one of the flanges provided on both ends has a through-hole through which the first piece is passed. . Furthermore, the magnetostrictive power generating element according to the present invention comprises a magnetostrictive unit having a magnetostrictive body at least in part thereof, a magnet that applies a magnetic bias to the magnetostrictive body, a coil, and a bobbin having a hollow portion and containing at least a part of the magnetostrictive body within the hollow portion, the bobbin having a wound portion around which the coil is wound on the outer circumferential side of the hollow portion, the magnetostrictive body unit comprising, within the hollow portion of the bobbin, a small deflection portion that deflects a small amount when vibration occurs in the magnetostrictive body unit, and a large deflection portion that deflects a larger amount than the small deflection portion when vibration occurs in the magnetostrictive body unit, and the distance between the inner walls that define the hollow portion in the bobbin and surround the periphery of the magnetostrictive body unit increases in the deflection direction of the magnetostrictive body unit as it moves from the portion facing the small deflection portion to the portion facing the large deflection portion. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a magnetostrictive power generating element that can increase the amount of power generation. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view showing a magnetostrictive power generating element according to a first embodiment. [Figure 2] FIG. 2 is a side view of the magnetostrictive generating element. [Figure 3] FIG. 2 is a side view showing a magnet and a magnetostrictive body unit. [Figure 4] FIG. [Figure 5] FIG. [Figure 6] FIG. 10 is a perspective view showing a magnetostrictive power generating element according to a modified example. [Figure 7] FIG. 10 is a side view showing a magnetostrictive generating element according to a modified example. [Figure 8] FIG. 10 is a partial cross-sectional view of the coil and its surroundings, showing a configuration in which some of the coils are wound multiple times. [Figure 9]FIG. 10 is a perspective view showing a magnetostrictive power generating element according to a second embodiment. [Figure 10] FIG. 10 is a perspective view showing a magnetostrictive power generating element according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] A magnetostrictive generating element 1 (1X) according to an embodiment of the present invention will be described below. The drawings used in the present embodiment are intended to illustrate the configuration and shape of the magnetostrictive generating element of the present invention and the arrangement of the members that make up the magnetostrictive generating element, and are not intended to limit the present invention. Furthermore, the drawings do not necessarily accurately represent the dimensional ratios of the length, width, and height of the magnetostrictive generating element 1 (1X). In addition, in all drawings, similar components are given similar reference numerals, and duplicate explanations are omitted as appropriate.

[0011] <<First Embodiment>> <Summary> First, an overview of the magnetostrictive generating element 1 according to this embodiment will be described mainly with reference to Fig. 1 to Fig. 3. Fig. 1 is a perspective view showing the magnetostrictive generating element 1 according to the first embodiment, and Fig. 2 is a side view of the magnetostrictive generating element 1. Fig. 3 is a side view showing the magnet 7 and the magnetostrictive body unit 2. In addition, the coil 6 is omitted in FIG. 1, and the magnetostrictive body 4 (see FIG. 3) and the magnet 7 (see FIG. 3) are omitted in FIGS. 1 and 2.

[0012] The magnetostrictive power generating element 1 according to this embodiment includes a magnetostrictive unit 2 having a magnetostrictive body 4 at least in part thereof, a magnet 7 (see FIG. 3) that applies a magnetic bias to the magnetostrictive body 4, a coil 6, and a bobbin 5 having a hollow portion 5b and accommodating at least a portion of the magnetostrictive body 4 within the hollow portion 5b. The bobbin 5 is characterized in that it has a wound portion 5c around which the coil 6 is wound, on the outer circumferential side of the portion where the hollow portion 5b is provided.

[0013] The "magnetostrictive unit 2" is not limited to one constituted by a U-shaped frame 3 made of a magnetic material and a magnetostrictive body 4. For example, the frame 3 may be formed linearly and held by another member in a cantilevered state, or held by another member in a doubly supported state. Furthermore, the frame 3 itself may be made of a magnetostrictive material (such as an iron-gallium alloy or an iron-cobalt alloy).

[0014] According to the above configuration, since the coil 6 is attached to the bobbin 5, unlike when the coil 6 is directly connected to the magnetostrictive unit 2 via an adhesive, the coil 6 does not restrict the vibration of the magnetostrictive unit 2 in the bending direction, and therefore it is possible to increase the amount of power generated. The generated current is taken out to the outside through an output circuit (not shown) to which both ends of the winding of the coil 6 are electrically connected. Furthermore, with the above-described configuration, no adhesive is required, and there is no need to manage the inventory of adhesive or adjust the amount of adhesive applied, and problems such as peeling of the adhesive do not occur. Furthermore, the coil 6 can be wound around the bobbin 5 before it is attached to the magnetostrictive unit 2, making it easier to wind the coil 6, and unlike when an air-core coil 6 is attached to the frame 3, the winding of the coil 6 is not damaged.

[0015] (Magnetostrictive unit) Next, the magnetostrictive unit 2 will be described mainly with reference to Fig. 4 in addition to Fig. 3. Fig. 4 is a perspective view showing the frame 3. As described above, the magnetostrictive unit 2 of this embodiment is composed of a frame 3 which is a magnetic material and a U-shaped leaf spring in side view, and a plate-shaped magnetostrictive body 4 which is attached to the upper surface of the frame 3 and is made of a magnetostrictive material (in this embodiment, an iron-gallium alloy). The magnetostrictive body 4 has an inverse magnetostriction effect in which it deforms due to compressive stress or tensile stress generated inside it when an external force is applied, and changes the magnetic flux due to the deformation.

[0016] The frame 3 and the magnet 7 form a magnetic circuit that passes through the magnet 7 shown in Fig. 3, the first arm 3c, the folded portion 3e, the second arm 3d of the frame 3 shown in Fig. 1, and the gap between the magnet 7 and the second arm 3d. In addition, an auxiliary magnet (not shown) may be disposed in a position close to but not in contact with the second arm 3d of the frame 3. When an external force is applied to the second arm 3d of the frame 3, causing it to vibrate, the magnetic resistance in the gap between the magnet 7 and the magnetostrictive body 4 attached to the frame 3 increases or decreases, thereby increasing the amount of change in the magnetic flux passing through the inside of the coil 6.

[0017] As shown in Fig. 1, the magnetostrictive unit 2 has a base end 3a and a flexible portion 3b. The base end 3a is a partial length region on the side that serves as the fixed end of the vibrating magnetostrictive unit 2 (frame 3). The flexible portion 3b is on the opposite side of the base end 3a in the longitudinal direction of the long magnetostrictive unit 2, and is a partial length region on the tip side that serves as the free end of the vibrating magnetostrictive unit 2 (frame 3). The flexible portion 3b is a portion that is vibrated when an external force is applied, and when the magnetostrictive unit 2 (frame 3) vibrates, a larger deflection occurs in the flexible portion 3b than in the base end 3a.

[0018] 1, a slit 3h is formed in the base end 3a of the frame 3, which is attached to an extension 5d of the bobbin 5 (described later), in the center in the left-right direction from the end face in the longitudinal direction. This slit 3h is for fastening together with the bobbin 5 using a fastener (not shown), and is formed in the same shape as the slit 5n of the bobbin 5 at a position that overlaps it vertically. Meanwhile, a slit is also formed at the tip of the flexible portion 3b. A weight (not shown) can be fixed to this slit with a screw or the like. By attaching a weight to the tip of the flexible portion 3b, the resonance frequency of the frame 3 can be adjusted as desired.

[0019] The magnetostrictive unit 2 of this embodiment is formed in a U-shape when viewed from the side, and comprises a first piece 3c including a base end 3a, a second piece 3d including a flexible portion 3b on the return side and around which the wound portion 5c of the bobbin 5 is arranged, and a folded portion 3e connected to the first piece 3c and the second piece 3d. The portion of the second arm 3d where the magnetostrictive body 4 is attached is a narrow portion 3i that is narrower than the other portions and is formed to have lower rigidity and bend easily. A wound portion 5c around which the coil 6 of the bobbin 5 is wound is disposed around this narrow portion 3i.

[0020] (bobbin) Next, the bobbin 5 according to this embodiment will be described mainly with reference to Fig. 5 in addition to Fig. 1 and Fig. 2. Fig. 5 is a perspective view showing the bobbin 5. The bobbin 5 according to this embodiment has the magnetostrictive unit 2 inserted therethrough, and the coil 6 attached to the outer periphery of the inching-type wound portion 5c, and is made of, for example, a non-elastic resin material.

[0021] 1, the bobbin 5 has an extending portion 5d extending in a direction away from the wound portion 5c. A base end portion 3a of the magnetostrictive unit 2 (frame 3) is fixed to the extending portion 5d. In this embodiment, the frame 3 is not fixed to the bobbin 5 at any portion other than the base end portion 3a, and is configured so as not to come into contact with the bobbin 5 even during vibration power generation.

[0022] In this embodiment, the "direction away from the wound portion 5c" refers to a direction away from the wound portion 5c in a direction perpendicular to the flange 5e of the bobbin 5. The extending portion 5d extends from the lower end of the flange 5e in a direction perpendicular to the flange 5e and away from the wound portion 5c.

[0023] According to the above configuration, the base end 3a of the magnetostrictive unit 2 (frame 3) is fixed to the extending portion 5d of the bobbin 5, which makes it possible to suppress relative movement of the bobbin 5 with respect to the magnetostrictive unit 2 in the direction (axial direction) away from the wound portion 5c in the direction perpendicular to the flange 5e. Also, it becomes easier to mount the magnetostrictive power generating element 1 together in other equipment.

[0024] Furthermore, as described above, since the bobbin 5 is made of an inelastic material, it is possible to prevent the vibrations transmitted to the base end 3a of the frame 3 fixed to the extension portion 5d of the bobbin 5 shown in Figure 1 from being absorbed.

[0025] The bobbin 5 has flanges 5e and 5f at both ends of the wound portion 5c, and the second arm 3d passes through the hollow portion 5b. At least one of the flanges 5e and 5f provided at both ends, that is, the flange 5e in this embodiment, has a through hole 5a formed therein through which the first arm 3c passes. Furthermore, since the through-hole 5a is formed in the flange 5e, the bobbin 5 can be easily attached to the magnetostrictive unit 2 which is formed in a U-shape.

[0026] In addition, a pair of legs 5j protruding downward are formed at two lower corners of the flange 5f according to this embodiment. A portion of the first arm 3c closer to the folded-back portion 3e than the portion passing through the through-hole 5a is passed between the pair of legs 5j.

[0027] The second piece 3d of the magnetostrictive unit 2 is attached so as to penetrate the center of the hollow portion 5b of the bobbin 5. In other words, the second piece 3d is disposed so as to penetrate the hollow portion 5b so as to leave space above and below the second piece 3d. Therefore, the hollow portion 5b is used as an operating space for the second piece 3d when it vibrates.

[0028] With this configuration, the bobbin 5 and the second arm 3d of the magnetostrictive unit 2 (frame 3) do not come into contact, and the bobbin 5 does not inhibit the vibration of the second arm 3d, thereby increasing the amount of power generated. Furthermore, the inner wall defining the hollow portion 5b of the bobbin 5 covers the second arm 3d, and can therefore be used as a stopper to suppress excessive vibration of the magnetostrictive unit 2.

[0029] <Modification> Next, a bobbin 5 according to a modified example will be described with reference mainly to Fig. 6 to Fig. 8. Fig. 6 is a perspective view showing a magnetostrictive generating element according to a modified example, and Fig. 7 is a side view showing a magnetostrictive generating element according to a modified example. Fig. 8 is a partial cross-sectional view of the coil 6 and its surroundings, showing a configuration in which some of the coils 6 are wound multiple times. In addition, the coil 6 is omitted in FIG. 6, and the magnetostrictive body 4 (see FIG. 3) and the magnet 7 (see FIG. 3) are omitted in FIGS. 6 and 7.

[0030] 7, the magnetostrictive unit 2 (frame 3) is provided, within the hollow portion 5b of the bobbin 5, with a small deflection portion 3f that deflects a small amount when vibration occurs in the magnetostrictive unit 2, and a large deflection portion 3g that deflects a larger amount than the small deflection portion 3f when vibration occurs in the magnetostrictive unit 2. The small deflection portion 3f and the large deflection portion 3g are part of the second arm 3d (see FIG. 1), and the large deflection portion 3g is located on the base end side of the second arm 3d, i.e., in a position close to the folded-back portion 3e of the second arm 3d. The inner walls 5g that define the hollow portion 5b in the bobbin 5 and surround the magnetostrictive unit 2 (frame 3) have a spacing between them that increases in the deflection direction of the magnetostrictive unit 2 (frame 3) as they move from the portion facing the small deflection portion 3f to the portion facing the large deflection portion 3g. That is, the hollow portion 5b defined by the inner wall 5g is formed in the shape of a truncated quadrangular pyramid (trapezoidal in side view).

[0031] By forming the inner wall 5g of the bobbin 5 in this manner, it is possible to ensure a difference in distance between the inner wall 5g in the longitudinal direction and the upper and lower limits of the bending of the frame 3, as shown by the two-dot chain lines in Fig. 7 when the frame 3 bends up and down. In other words, when the magnetostrictive unit 2 (frame 3) bends, the bending can prevent the magnetostrictive unit 2 from coming into contact with the inner wall 5g of the bobbin 5, which would inhibit the vibration of the magnetostrictive unit 2 from being inhibited. This increases the inverse magnetostriction effect and increases the increase or decrease in the magnetic gap between the magnet 7 and the frame 3, thereby increasing the amount of power generated by the magnetostrictive power generation element 1.

[0032] 6, the bobbin 5 has outer walls 5h located on the outer peripheral side of the inner wall 5g and constituting the wound portion 5c. The spacing between the outer walls 5h increases in the deflection direction of the magnetostrictive unit 2 from the portion facing the small deflection portion 3f toward the portion facing the large deflection portion 3g.

[0033] That is, the outer wall 5h (the wound portion) between the flanges 5e and 5f of the bobbin 5 according to this embodiment is formed in the shape of a truncated quadrangular pyramid (trapezoidal in side view). That is, of the four faces of the outer wall 5h, two opposing side faces are formed parallel to each other, and the remaining two opposing upper and lower faces are formed so as to converge along the longitudinal direction toward the folded portion 3e (see Figure 4).

[0034] By forming the outer wall 5h in this manner, both the small deflection portion 3f and the large deflection portion 3g of the magnetostrictive unit 2, which deflect due to vibration, can be brought closer to the coil 6 as shown in Figure 7, thereby increasing the change in magnetic flux density and increasing the induced electromotive force by the coil 6.

[0035] As shown in FIG. 8, in the coil 6, it is preferable that the number of turns in the length region corresponding to the small deflection portion 3f in the wound portion 5c is greater than the number of turns in the length region corresponding to the large deflection portion.

[0036] For example, in the present embodiment, the coil 6 is wound in a single layer from the flange 5e to the center in the axial direction of the bobbin 5, and is wound in a double layer from the center to the flange 5f, and is disposed so that the outer surface is flat. However, the present invention is not limited to this configuration, and the number of turns and the length of the portions with different numbers of turns may be changed depending on the wire diameter of the coil 6 and its length in the axial direction.

[0037] According to the above configuration, by utilizing the space outside the outer wall 5h of the bobbin 5 and suitably arranging the coil 6, the induced electromotive force of the coil 6 can be increased. In particular, by increasing the number of turns in the length region corresponding to the small vibration portion 3f on the base end side (the folded portion 3e side) of the second arm portion 3d where distortion becomes larger, the influence of the change in magnetic flux density due to the inverse magnetostriction effect of the magnetostrictive body 4 can be increased.

[0038] <<Second embodiment>> Next, a magnetostrictive generating element 1X according to a second embodiment will be described mainly with reference to Figs. 9 and 10. Figs. 9 and 10 are perspective views showing the magnetostrictive generating element 1X according to the second embodiment. Note that the magnetostrictive body 4 (see Fig. 3) is not shown in Fig. 9. Also, the windings of the coil 6 are not shown in Figs. 9 and 10.

[0039] The bobbin 15 of the magnetostrictive generating element 1X has a pair of flanges 15e and 15f at positions facing both ends of the coil 6. At least one of the flanges 15e and 15f (flange 15f in this embodiment) is provided with a pin 10 for winding an end of the coil 6 thereon. According to the above configuration, the end of the coil 6 is wound around the pin 10 and soldered together with a conductor, so that power can be supplied to other elements, and breakage of the conductor can be prevented.

[0040] The flange 15f in this embodiment has a pair of generally rectangular parallelepiped protrusions 15i that are spaced apart in the left-right direction and protrude outward in the axial direction. The pins 10 are provided on the upper surfaces of the pair of protrusions 15i. In this way, by providing the pin 10 in a portion formed by the protrusion 15i with a thick wall in the axial direction, it is possible to prevent the pin 10 from breaking off from the flange 15f even when vibration is applied to the magnetostrictive generating element 1X.

[0041] The present invention is not limited to the above configuration, as long as pins 10 are provided on flanges 15e, 15f that face both ends of coil 6. For example, pins 10 may be provided only on flange 15e, or on both flanges 15e and 15f, and may be formed to protrude not only upward but also in the axial direction or left-right direction.

[0042] An upper extending portion 15j extends from the upper side of the flange 15e, and a lower extending portion 15k extends from the lower end toward the base end in the longitudinal direction. Specifically, the lower extending portion 15k is formed in a plate shape and extends longer than the upper extending portion 15j. A recess 15m having a rectangular shape in a plan view is formed on the upper surface of the lower extension 15k. The base end 3a of the frame 3 is accommodated within the recess 15m. A mounting hole 15n is formed in the recess 15m, penetrating vertically, at a position overlapping with the slit 3h of the frame 3. A fastener (not shown) is passed through the mounting hole 15n and fastened together with the slit 3h of the frame 3.

[0043] The various components of the magnetostrictive generating element of the present invention do not need to exist independently of one another, and it is acceptable for multiple components to be formed as a single member, for one component to be formed from multiple members, for one component to be part of another component, or for part of one component to overlap with part of another component, etc.

[0044] The above embodiment encompasses the following technical ideas. (1) a magnetostrictive body unit having a magnetostrictive body at least in a portion thereof; a magnet that applies a magnetic bias to the magnetostrictive body; A coil and a bobbin having a hollow portion and accommodating at least a portion of the magnetostrictive body within the hollow portion; The bobbin has a wound portion around which the coil is wound, the wound portion being located on the outer circumferential side of the hollow portion. (2) the magnetostrictive unit has a base end and a flexible portion, the bobbin has an extending portion extending in a direction away from the wound portion, The magnetostrictive power generating element according to (1), wherein the base end of the magnetostrictive unit is fixed to the extension portion. (3) the magnetostrictive unit is formed in a U-shape in a side view and includes a first piece including a base end, a second piece including a flexible portion and located on the return side, and around which the wound portion is disposed, and a folded-back portion connected to the first piece and the second piece, the bobbin has flanges at both ends of the wound portion, and the second piece is passed through the hollow portion; The magnetostrictive generating element according to (1) or (2), wherein a through hole through which the first arm portion is inserted is formed in at least one of the flanges provided at both end portions. (4) the magnetostrictive unit includes, within the hollow portion of the bobbin, a small deflection portion that deflects a small amount when vibration occurs in the magnetostrictive unit, and a large deflection portion that deflects a larger amount than the small deflection portion when vibration occurs in the magnetostrictive unit, The magnetostrictive power generating element according to any one of (1) to (3), wherein the inner walls defining the hollow portion in the bobbin and surrounding the magnetostrictive unit have a distance between the inner walls that increases in the deflection direction of the magnetostrictive unit from the portion facing the small deflection portion toward the portion facing the large deflection portion. (5) the bobbin has an outer wall that is located on the outer circumferential side of the inner wall and that constitutes the wound portion, The magnetostrictive power generating element according to (4), wherein the spacing between the outer walls increases in the deflection direction of the magnetostrictive body unit from the portion facing the small deflection portion toward the portion facing the large deflection portion. (6) The magnetostrictive power generating element according to (5), wherein the number of turns of the coil in the length region corresponding to the small deflection portion in the wound portion is greater than the number of turns in the length region corresponding to the large deflection portion. (7) the bobbin has a pair of flanges at positions facing both ends of the coil, The magnetostrictive power generating element according to any one of (1) to (6), wherein a pin for tying an end of the coil to at least one of the flanges is provided. [Explanation of symbols]

[0045] 1. 1x magnetostrictive power generating element 2 Magnetostrictive unit 3 frames 3a Proximal end 3b flexure 3c 1st piece 3d second piece 3e Folded part 3f Small swing part 3g Large swing part 3h slit 3i narrow part 4 Magnetostrictive body 5 bobbins 5a through hole 5b Hollow part 5c Winding part 5d extension 5e, 5f flange 5g inner wall 5h Exterior wall 5j legs 5n slit 6 coils 7. Magnets 10-pin 15 bobbins 15e, 15f flange 15i protrusion 15j Upper extension part 15k lower extension 15m recess 15n mounting hole

Claims

1. a magnetostrictive body unit having a magnetostrictive body at least in a portion thereof; a magnet that applies a magnetic bias to the magnetostrictive body; A coil and a bobbin having a hollow portion and accommodating at least a portion of the magnetostrictive body within the hollow portion; the bobbin has a wound portion around which the coil is wound, on the outer circumferential side of a portion where the hollow portion is provided, the magnetostrictive unit is formed in a U-shape in a side view, and includes a first piece including a base end, a second piece including a flexible portion and located on a return side, and around which the wound portion is disposed, and a folded portion connected to the first piece and the second piece, the bobbin has flanges at both ends of the wound portion, and the second piece is passed through the hollow portion; The magnetostrictive power generating element has a through hole formed in at least one of the flanges provided at both end portions, through which the first arm portion is inserted.

2. A magnetostrictive body unit having a magnetostrictive body in at least a portion thereof; a magnet that applies a magnetic bias to the magnetostrictive body; A coil and a bobbin having a hollow portion and accommodating at least a portion of the magnetostrictive body within the hollow portion; the bobbin has a wound portion around which the coil is wound, on the outer circumferential side of a portion where the hollow portion is provided, the magnetostrictive unit includes, within the hollow portion of the bobbin, a small deflection portion that deflects a small amount when vibration occurs in the magnetostrictive unit, and a large deflection portion that deflects a larger amount than the small deflection portion when vibration occurs in the magnetostrictive unit, A magnetostrictive power generation element in which the distance between the inner walls that define the hollow portion in the bobbin and surround the magnetostrictive unit increases in the deflection direction of the magnetostrictive unit from the portion facing the small deflection portion toward the portion facing the large deflection portion.

3. the bobbin has an outer wall that is located on the outer circumferential side of the inner wall and that constitutes the wound portion, The magnetostrictive power generating element according to claim 2, wherein the spacing between the outer walls increases in the deflection direction of the magnetostrictive body unit from the portion facing the small deflection portion toward the portion facing the large deflection portion.

4. The magnetostrictive power generating element according to claim 3 , wherein the number of turns of the coil in the length region corresponding to the small deflection portion of the wound portion is greater than the number of turns in the length region corresponding to the large deflection portion.

5. the magnetostrictive unit has a base end and a flexible portion, the bobbin has an extending portion extending in a direction away from the wound portion, The magnetostrictive power generating element according to claim 1 , wherein the base end of the magnetostrictive unit is fixed to the extension.

6. the bobbin has a pair of flanges at positions facing both ends of the coil, The magnetostrictive generating element according to claim 1 , wherein a pin for tying an end of the coil to at least one of the flanges is provided on at least one of the flanges.

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