JP6303846B2 - Vibration power generator - Google Patents

Description

  The present invention relates to a vibration power generation apparatus in which both ends of a weight are supported by a magnetostrictive material, and a connection point between the fulcrum of the magnetostrictive material and the weight is provided with a degree of freedom of rotation.

  As a power generation technique using vibration, a power generation method using a piezoelectric element is well known. Many of the power generation methods using piezoelectric elements are to generate power by deforming the piezoelectric elements by applying external force to the piezoelectric elements in some way.

  As a power generation method using a piezoelectric element, for example, there is a method described in Patent Document 1 below. That is, the following Patent Document 1 describes a sound power generation device that generates electric power with a piezoelectric element using fluctuations in air pressure due to sound, and a vibration power generation device that generates electric power with piezoelectric elements using pressure fluctuations caused by vibration. ing.

A power generation method using a magnetostrictive element instead of a piezoelectric element has also been proposed. As a power generation method using a magnetostrictive element, for example, there is a method described in Patent Document 2 below.
FIG. 13 is a diagram illustrating a configuration example of a power generation element using vibration described in Patent Document 2 below. That is, FIG. 13A is a top view showing the configuration of the power generating element shown in Patent Document 2 below, and FIG. 13B is a side view showing the configuration of the power generating element shown in Patent Document 2 below. is there.

  13 (a) and 13 (b), the power generating element 100 includes connecting yokes 100a and 100b, magnetostrictive rods 110a and 110b, coils 120a and 120b, permanent magnets 140a and 140b, and a passive yoke 150. Configured.

  FIG. 14 is a diagram illustrating a configuration example of the power generation device when the power generation element illustrated in FIG. 13 has a cantilever configuration. In FIG. 14, the power generation device has a cantilever structure in which the connecting yoke 100a of the power generating element 100 is fixed by a fixing member. By applying a bending stress P to the connecting yoke 100b, the magnetostrictive rods 110a and 110b are bent and deformed. As a result, due to the inverse magnetostrictive effect generated in the magnetostrictive rods 110a and 110b, the magnetic flux passing through the coils 120a and 120b (see FIG. 13 (a)) changes, so that an induced voltage (or induced current) is generated in the coils 120a and 120b. To do. As a result, power can be generated by applying vibration to the power generation element 100.

JP 2006-166694 A Japanese Patent No. 4905820

  In the power generation method using the piezoelectric element described in Patent Document 1, the piezoelectric material constituting the piezoelectric element is a brittle material and is a material that is weak against bending and impact. For this reason, there is a problem that it is difficult to apply excessive bending and impact in order to increase the amount of power generation because excessive force cannot be applied. In addition, the piezoelectric element has a high impedance at a low frequency, and when a load having a lower impedance than that of the piezoelectric element is connected, the voltage generated in the load is small, so the power obtained by power generation is small and the power generation efficiency is low. There is a problem.

  On the other hand, the magnetostrictive material composing the magnetostrictive rods 110a and 110b described in Patent Document 2 is a ductile material and is more resistant to bending and impact than the piezoelectric material. Therefore, power generation is increased by applying large bending and impact. It is possible to make it. Further, since the impedance of the element is lower than that of the piezoelectric material, the problem of the piezoelectric material described in Patent Document 1 can be solved because there is little decrease in power generation efficiency due to connection of a load with low impedance.

  However, since the vibration power generation apparatus described in Patent Document 2 generates a bending deformation of the magnetostrictive rod while vibrating and requires a large excitation force from the vibration source to generate power, the vibration energy is not absorbed well and the power generation efficiency is low. There is a problem that the vibration is reduced, or excitation is not caused by external vibration in a direction orthogonal to the vibration direction of the weight.

Accordingly, the present invention is intended to solve the following problems in a vibration power generator using a conventional magnetostrictive element. That is,
(1) The frequency range of the vibration source capable of generating power efficiently is narrow, and the power generation efficiency is reduced when the vibration is away from a specific resonance frequency.
(2) In a vibration source with a small excitation force, the power generation efficiency is low because the expansion and contraction strain generated inside the magnetostrictive element is small.
(3) Only the external vibration along the vibration direction of the weight is excited, and the power generation efficiency is low for the external vibration perpendicular to the vibration direction of the weight.

  In order to solve the above-mentioned problems, the present invention fixes two rod-shaped magnetostrictive members to a weight body via a member that secures a degree of freedom of rotation, and the angle formed by the two magnetostrictive members is approximately linear. Then, one end of the two magnetostrictive members is fixed to the support base through a member that ensures the same degree of freedom of rotation. When the weight body vibrates left and right due to external vibration, the tension of the magnetostrictive member varies and the strain of the magnetostrictive member changes, so that the density of magnetic flux passing through the magnetostrictive member also changes. Electric power is generated by generating at both ends of the coil.

  More specifically, the invention according to claim 1 is configured such that a support base that receives vibration from a vibration source, two rod-shaped magnetostrictive members made of a magnetostrictive material, and the magnetostrictive member are connected to each other. A vibrating weight body, a rod-shaped or cylindrical magnetic member connected to the magnetostrictive member to form a loop-shaped magnetic circuit, a permanent magnet for supplying a bias magnetic field to the magnetic circuit, and a chain connected to the magnetic circuit Vibration power conversion means composed of magnetic coils wound so as to intersect with each other, and the two magnetostrictive members are fixed to the weight body via a member that ensures a degree of freedom of rotation. One end of the two magnetostrictive members is fixed via a member that secures a degree of freedom of rotation with respect to the support base so that the magnetostrictive members are substantially linear, and the vibration power is accompanied by vibration of the weight body. When the magnetostrictive member of the converting means expands or contracts It is characterized in that conductive.

  According to a second aspect of the present invention, in the first aspect of the present invention, the vibration power converting means is configured such that the vibration portion composed of the magnetostrictive member and the weight body has two total lengths of the support base. It is slightly longer than the interval between the fixed positions, and the angle formed between the central axis connecting the two fixed positions of the support base and the magnetostrictive member and the magnetostrictive member is larger than 0 degree and smaller than 5 degrees. It is a feature.

  According to a third aspect of the present invention, in the first aspect of the present invention, the vibration power converting means applies a tension applied to both ends of the magnetostrictive member so that a compressive force mainly acts on the magnetostrictive element. The magnetostrictive member has a structure in which the magnetostrictive member is inverted and transmitted to the magnetostrictive element.

  According to a fourth aspect of the present invention, in the first aspect of the present invention, the vibration power converting means includes an amplitude limiting means including an annular shape, a cylindrical shape, or a plurality of protrusions around the weight body. It is characterized by being arranged.

  The invention according to claim 5 is the invention according to claim 4, wherein the amplitude limiting means is an annular shape or a cylindrical shape, and the amplitude limiting means contacts one or more protrusions with the weight body. Or the amplitude limiting means includes one or more protrusions having a plurality of protrusions and different distances from a central axis connecting the fixing points of the support base.

  According to a sixth aspect of the present invention, in the first aspect of the present invention, the vibration power converting means arranges the magnetostrictive member in a substantially horizontal direction and suspends the weight body with an elastic body. Thus, the drooping of the weight body due to gravity is canceled, and the initial position of the weight body when there is no external vibration is held on the central axis.

ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to obtain the vibration electric power generating apparatus from which high power generation efficiency is acquired with the external vibration over a wide frequency range.
In addition, when the magnetostrictive element has a non-uniform stress distribution in the cross section like bending deformation (mixed compressive force and tensile stress), the inverse magnetostrictive effect cancels out and the power generation efficiency decreases. Since a force acts only in the length direction and a nearly uniform stress distribution is obtained, a decrease in power generation efficiency due to the stress distribution hardly occurs in principle, so that the power generation efficiency can be increased.

  Furthermore, in the present invention, the weight body can hardly vibrate in the direction of the central axis connecting the fixed points of the support base, but can vibrate in any direction orthogonal to the central axis, so that high power generation efficiency can be obtained. In the prior art, a certain high power generation efficiency is obtained with respect to external vibration in one axial direction along the vibration of the weight body. However, in the present invention, high power generation efficiency is obtained with respect to external vibration in two axial directions. It is possible to effectively use external vibration with a single vibration power generation device as compared with the prior art.

It is a figure which shows the structure of the vibration electric power generating apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows the structure of the vibration electric power generating apparatus which concerns on the 2nd Embodiment of this invention. It is a figure which shows the structure of the vibration electric power generating apparatus which concerns on the 3rd Embodiment of this invention. It is a figure which shows the internal structure of FIG. It is a figure which shows the structure of the vibration electric power generating apparatus which concerns on the 4th Embodiment of this invention. It is a figure which shows the internal structure of FIG. It is a figure which shows the structure of the vibration electric power generating apparatus which concerns on the 5th Embodiment of this invention. It is a figure which shows the internal structure of FIG. It is a figure explaining the basic concept of this invention. It is FIG. (1) which shows the numerical solution of the equation of motion for demonstrating the vibration electric power generating apparatus which concerns on the 1st Embodiment of this invention. It is FIG. (2) which shows the numerical solution of the equation of motion for demonstrating the vibration electric power generating apparatus which concerns on the 1st Embodiment of this invention. It is FIG. (The 3) which shows the numerical solution of the equation of motion for demonstrating the vibration electric power generating apparatus which concerns on the 1st Embodiment of this invention. It is FIG. (The 4) which shows the numerical solution (horizontal placement) of the equation of motion for demonstrating the vibration electric power generating apparatus which concerns on the 1st Embodiment of this invention. It is a figure (the 1) which shows the numerical solution of the equation of motion for demonstrating the vibration electric power generating apparatus which concerns on the 2nd Embodiment of this invention. It is a figure (the 2) which shows the numerical solution of the equation of motion for demonstrating the vibration electric power generating apparatus which concerns on the 2nd Embodiment of this invention. It is a figure which shows the structural example for negating the gravity which acts on a weight body when the vibration electric power generating apparatus of this invention is installed horizontally. It is the top view and side view which show the structure of the conventional electric power generation element. It is a figure which shows the structural example of the electric power generating apparatus at the time of setting the electric power generating element shown in FIG. 13 to the cantilever structure.

Hereinafter, embodiments of the present invention will be described in detail.
Before describing the embodiment of the present invention, the basic concept of the present invention will be described with reference to FIG. In FIG. 9, parts such as a magnet, a yoke, and a coil constituting the vibration power generation apparatus are not shown for the sake of simplicity of illustration. Fixing points at both ends of the magnetostrictive member (magnetostrictive element) are fixed by a freely rotatable member (such as a ball joint, a universal joint, or a hanging metal fitting). When the weight body vibrates from side to side due to external vibration, the tension of the magnetostrictive member changes and the strain of the magnetostrictive member changes, and the magnetic flux density passing through the magnetostrictive member (magnetostrictive element) also changes due to the inverse magnetostrictive effect. Electric power is generated by generating electric power at both ends of a coil (not shown).

  More specifically, in FIG. 9, if the weight is regarded as a mass point of mass m (actually italic letters because it represents a scalar quantity), and the weight position vector is x (actually bold because it represents a vector quantity). The equation of motion of the weight body seen from the support table and the observer moving at a relative speed of 0 is expressed as the following equation (1).

When the above formula (1) is arranged, the following formula (2) is obtained.

here,

I put it.

Note that U (x) (actually bold because it represents a vector quantity) is an average value of unit vectors from the fixed point position vectors p ₁ and p ₂ toward the weight position vector x. In FIG. 9, displacements and attenuations other than in the horizontal direction are ignored (y = z = c = 0) (these represent scalar quantities and are actually italic letters), and the fixed point position vectors p ₁ and p ₂ and the weight position vector If the angle formed by x is θ and the unit vector in the x-axis direction is e _x ,

Therefore, the above equation (2) becomes the following equation (5). That is,

It becomes. Since the above equation (5) is equivalent to the equation of motion when the weight is connected to the spring of the spring constant 2k (1-cosθ) (k is an italic letter because k represents a scalar quantity), the resonance frequency of this system is It can be represented by the following formula (6).

From the above equation (6), the following results are derived.
(B) Resonance at a lower frequency as the amplitude is smaller (when θ → 0, f → 0).
(B) The resonance frequency increases as the angle θ increases (maximum value √ (2k / m)) (k and m represent scalar quantities, so they are actually italic letters)
It can be seen that the effect (a) resonates with a small amplitude even at a very low frequency. Further, since the amplitude and the resonance frequency change according to the frequency due to the effect (b), excitation can be performed in a wide range of frequencies.

  In a normal spring-weight system, the resonance frequency does not change with √ (k / m) (k, m represents a scalar quantity, so it is actually an italic character), so to reduce the resonance frequency, k (scalar quantity) Actually, it is necessary to reduce (use italic letters) (use a soft spring) or increase m (actually italic letters because it represents a scalar quantity) (heavier weight), but in the present invention θ is reduced even at low frequencies. Automatically resonates. Further, when the frequency of the external vibration is constant, resonance does not occur when the vibration becomes larger than θ determined by the resonance frequency of the above formula (6), so that there is an effect that an unlimited increase in amplitude leading to destruction of the apparatus does not occur.

  Furthermore, in the structure of the present invention, among the forces exerted by the magnetostrictive member on the weight body, the vertical components in FIG. 9 cancel each other and a large force is generated even with a small amplitude, so that it is possible to generate power effectively from weak vibrations. it can.

[Embodiment 1]
FIG. 1 is a diagram illustrating a configuration of a vibration power generation apparatus according to a first embodiment of the present invention. In FIG. 1, the vibration power generation apparatus according to the first embodiment of the present invention includes, as an example, a weight body 2 fixed between two magnetostrictive members (magnetostrictive elements) 1, and the remaining end of the magnetostrictive member 1 is connected. Fix to the support 3. A ball joint 4 is used as a member for fixing the magnetostrictive member 1 to provide a degree of freedom of rotation. The magnetostrictive member 1 and the ball joint 4 are firmly fixed by an arbitrary method such as screwing, welding, or diffusion friction bonding.

As a member having a degree of freedom of rotation, a ball joint, a universal joint, a hanging metal fitting, or the like can be used. The characteristics required in this embodiment are as follows.
(A) Even if a strong tensile force is applied, the deformation is small.
(B) There is little friction and it can rotate smoothly.
(C) Even after a long period of time, there is little wear and there is no backlash.
(D) Not only tension but also compressive force can be transmitted (necessary for the second embodiment described later).

It is desirable to reduce friction by using lubricating oil or a lubricious material for the joint surface of the joint, and a ball bearing may be used.
In FIG. 1, the central axis is drawn in the vertical direction, but this apparatus can generate power even when the central axis is arranged in the horizontal direction. However, resonance is less likely to occur because the weight is stabilized in a state where it is displaced downward due to gravity. Even in the case of such horizontal placement, power generation characteristics close to those in the case of vertical placement can be obtained by suspending the weight body 2 with a weak spring and canceling gravity as shown in FIG.

  A coil 5 in which a conducting wire is wound around the magnetostrictive member 1 is installed, and a magnet 6 is arranged outside the coil 5. The polarity of the magnet 6 is set so that the NS direction is along the central axis. A magnetic body (magnetic member) 7 is fixed to both ends of the magnet 6 to form a magnetic circuit passing from the magnet 6 through the magnetostrictive member 1. As the magnet 6, any permanent magnet such as neodymium or ferrite can be used. As the magnetic body (magnetic member) 7, an arbitrary ferromagnetic body such as iron or an alloy thereof can be used.

  In FIG. 1, the length of the magnet 6 and the length of the coil 5 are substantially equal, but the length of the magnet 6 is shortened in consideration of the magnetic flux density of the magnetic circuit and the cost of the magnet. The magnetic member 7 can be extended. Actually, power is taken out from an arbitrary place of the coil 5 by a conducting wire and a connecting terminal, but the conducting wire and the connecting terminal are omitted in FIG.

  Either one of the magnetic bodies (magnetic members) 7 is fixed to the magnetostrictive member 1, but the other is opened with a slight gap between the magnetostrictive member 1 so as not to prevent expansion and contraction of the magnetostrictive member 1. Similarly, the coil 5 is not fixed to the magnetostrictive member 1.

  The support 3 is selected from a material and a structure that have high rigidity and are difficult to deform. In this example, a hollow cylinder of stainless steel (SUS304) is used. The support base 3 is actually composed of a plurality of parts, but details of the parts are omitted in FIG.

FIG. 10 shows a numerical solution of the equation of motion (see the above-described equation (2)) in the first embodiment of the present invention described above. The left side of FIG. 10 is a position coordinate of the weight body and the stress of the magnetostrictive member (tensile stress is a positive value) from 5 seconds after the vibration, and the right side is a locus of the xy coordinate of the weight body. Calculation conditions are magnetostrictive member φ2 × 50mm, weight 0.2kg, damping ratio 1%, acceleration by external vibration is given by F / m = (F _dir / | F _dir |) gGsin (2πft) (F _dir : vibration Direction vector, m: mass, g: gravitational acceleration = 9.80665 [m ² / s], G: maximum acceleration, f: frequency [Hz], t: time [s]) (m, g, G, f, Since t represents a scalar quantity, it is actually an italic character), and F _dir (vibration direction vector) is (1,1,0) and a direction orthogonal to the central axis (Z axis).

  FIG. 10A is a diagram (part 1) illustrating a numerical solution of an equation of motion for explaining the vibration power generation apparatus according to the first embodiment of the present invention. The frequency of external vibration is 3 Hz, the maximum acceleration is 0.3 G, and gravity is − In the case of the Z direction (vertical placement), the maximum stress amplitude was 14.7 MPa. FIG. 10B is a diagram (part 2) illustrating a numerical solution of the equation of motion for explaining the vibration power generation apparatus according to the first embodiment of the present invention, in the case of a frequency of 3 Hz and a maximum acceleration of 0.1 G, and the maximum The stress amplitude is 9.9 MPa, and even if the maximum acceleration is reduced to 1/3, the stress amplitude is only reduced to about 2/3. FIG. 10C is a diagram (part 3) illustrating a numerical solution of the equation of motion for explaining the vibration power generation apparatus according to the first embodiment of the present invention, in the case where the frequency is 1 Hz and the maximum acceleration is 0.3 G, and the maximum The stress amplitude is 11.7 MPa, indicating that power generation is possible even at low frequencies. Moreover, since the stress changes at a higher frequency than the external vibration with a frequency of 1 Hz, a high power generation output can be obtained even at a low frequency.

  FIG. 10D is a view (No. 4) showing a numerical solution (horizontal placement) of the equation of motion for explaining the vibration power generator according to the first embodiment of the present invention, and is horizontally arranged with the same external vibration as FIG. 10A. Since the gravity in the -Y direction is stronger than the external vibration, the weight is almost stable near x = 0mm and y = -1mm, so the maximum stress amplitude is 1 / 4MPa and 1/4 To a degree. In order to increase the power generation efficiency in the horizontal position, it is desirable to employ a configuration in which the weight body is suspended by a weak spring as shown in FIG. 12 for preventing the weight body from drooping due to gravity. If this method is adopted, the influence of gravity is eliminated, so that the maximum stress amplitude equivalent to that in FIG. 10A can be obtained.

[Embodiment 2]
FIG. 2 is a diagram illustrating a configuration of a vibration power generation apparatus according to the second embodiment of the present invention. In FIG. 2, the vibration power generation device according to the second embodiment of the present invention is configured such that the entire length of the vibration portion composed of the magnetostrictive member (magnetostrictive element) 1 and the weight body 2 is an interval between two fixed positions of the support 3 The structure is slightly longer and the angle formed by the two magnetostrictive members 1 is smaller than 180 degrees.

  In this structure, when the excited weight body 2 approaches the central axis connecting the two fixed positions of the support base 3, a compressive force acts on the magnetostrictive member 1. For this reason, the stress amplitude (the sum of absolute values of compressive force and tensile stress) acting on the magnetostrictive member 1 is increased, and the power generation output is increased. Further, since the maximum tensile stress that causes fatigue failure of the magnetostrictive element 1 is smaller than that shown in FIG. 1, the durability of the magnetostrictive member 1 is improved.

As shown in FIG. 9, when the initial position of the weight body 2 is (x ₀ , 0,0) (x ₀ represents a scalar quantity, so it is actually an italic character), the desired angle range is x ₀ / L (where x _{0 0} and L represent scalar quantities, so the actual italic letters) are in the range of 1 to 3% (L is the length of the magnetostrictive member 1 when no load is applied) (L is the italic letters because L represents the scalar quantity). Assuming that the angle formed by the central axis and the magnetostrictive member 1 is θ, θ = tan ⁻¹ (x ₀ /L)=0.5 to 2.0 degrees (note that x ₀ , L represents a scalar quantity, so it is actually an italic character). The desired angle range varies depending on the material and structure, but a maximum of about 5 degrees is considered the upper limit. If the angle θ is too large, the weight body 2 cannot move near the central axis and power generation efficiency is reduced, and if θ is small, the compressive stress acting on the magnetostrictive member 1 becomes small and becomes the same as in the first embodiment.

FIG. 11 shows a numerical solution of the equation of motion (formula (2) described above) in the present embodiment. The calculation conditions were set to be the same as those shown in FIG. 10, and x ₀ / L (note that it is actually italic letters because x ₀ and L represent scalar quantities) is 1.5%.

  FIG. 11A is a diagram (part 1) illustrating a numerical solution of an equation of motion for explaining a vibration power generator according to a second embodiment of the present invention, in which the frequency of external vibration is 3 Hz, the maximum acceleration is 0.3 G, and the gravity is Z In the case of the axial direction (vertical placement), it can be seen that the maximum stress amplitude is 29.2 MPa, which is about twice as large as that in FIG. 10A, and compressive stress (negative value) is generated.

  FIG. 11B is a diagram (part 2) illustrating a numerical solution of the equation of motion for explaining the vibration power generation apparatus according to the second embodiment of the present invention, in the case of a frequency of 1 Hz and a maximum acceleration of 0.1 G. The stress amplitude was 6.0 MPa, which was lower than that in FIG. 10B. This is because the weight body 2 rotates around the central axis so as to draw a circle, and by arranging a protrusion for limiting the amplitude (see FIG. 3 and claim 5), the stress amplitude can be reduced by preventing such rotational movement. Can be increased.

[Embodiment 3]
3 and 4 are diagrams showing the configuration of the vibration power generator according to the third embodiment of the present invention. 3 and 4, the vibration power generation apparatus according to the third embodiment of the present invention is configured such that the direction of the force acting on the magnetostrictive member 1 is reversed by the metal fitting 8 so that compressive stress is applied. By comprising in this way, the tensile stress which becomes a factor of fatigue failure does not act on the magnetostrictive member 1, and durability improves. Since the magnetostrictive member 1 is firmly fixed to the metal fitting 8 by the fixing pin 10 (see FIG. 4) and receives both compressive stress and tensile stress, the entire length of the vibrating portion composed of the magnetostrictive member 1 and the weight body 2 is supported by the support base. 3 is slightly longer than the interval between the two fixed positions, and the angle formed between the central axis connecting the two fixed positions of the support base 3 and the magnetostrictive member 1 and the magnetostrictive member 1 is greater than 0 degree and greater than 5 degrees. It is also possible to adopt a small configuration (see claim 2) at the same time.

  The weight body 2 is integrated with the ball joint 4 by screwing the weight joint cover 2b with the weight joint base 2c inserted into the weight outer ring 2a. By appropriately setting the inner diameter of the support base housing 3a, the amplitude of the weight body 2 can be limited.

  Further, the projection 9a is for inhibiting the rotational movement as shown in FIG. 11B. The support base joint cover 3b and the support base joint base 3c are coupled to the support base casing 3a with screws 11, but may be coupled by other methods. The support base spacer 3d has an effect of adjusting the movement of the ball joint 4 and the overall length of the support base 3.

[Embodiment 4]
5 and 6 are diagrams showing the configuration of the vibration power generator according to the fourth embodiment of the present invention. 5 and 6, the vibration power generation apparatus according to the fourth embodiment of the present invention reverses the force acting on the magnetostrictive member 1 in the same manner as the vibration power generation apparatus according to the third embodiment of the present invention described above. However, since the magnetostrictive member 1 and the magnetic body (magnetic member) 7 have a cylindrical nested structure, the number of components is smaller than that of the vibration power generation apparatus according to the third embodiment of the present invention described above. I have to.

  Further, the magnet 6 is divided into upper and lower parts, and the magnetic poles are directed from the central axis toward the outside and toward the inside, thereby forming a magnetic circuit passing from the magnetostrictive member 1 to the magnetic body (magnetic member) 7. If the magnet 6 is sufficiently strong, one of the magnets can be replaced with a magnetic body (magnetic member) 7.

  Further, the rod connected from the metal joint 8 and the ball joint 4 inside the magnetostrictive member 1 is made of a non-magnetic metal such as stainless steel (nonmagnetic member) so that the magnetic flux does not pass through portions other than the magnetostrictive member 1. There is a need.

  In the fourth embodiment, the shape of the support base housing 3a is a rectangular parallelepiped, and a plate with a circular hole is disposed inside as the amplitude limiting means 9. Further, the projection 9a is for preventing the rotational movement of the weight body 2 as in the third embodiment (see section CC in FIG. 5).

[Embodiment 5]
7 and 8 are diagrams showing the configuration of the vibration power generator according to the fifth embodiment of the present invention. 7 and 8, the vibration power generation apparatus according to the fifth embodiment of the present invention is mainly composed of the magnetostrictive member 1 like the vibration power generation apparatuses according to the first and second embodiments of the present invention described above. Tensile stress acts on. The magnetostrictive member 1 is formed into a cylindrical shape, and the coil 5, the magnet 6, and the magnetic body (magnetic member) 7 are accommodated therein, thereby forming a compact vibration power generation unit.

  The universal joints 4a and 4b are used as members that can be fixed with a degree of freedom of rotation. By fixing the weight body 2 to the central universal joint shaft 4b, the total number of universal joints becomes three, and the number of joints can be reduced by one as compared with other embodiments using ball joints (see FIG. 8).

  In the fifth embodiment, the support base 3 is shaped like a bowl so that the vibration state of the weight body 2 can be observed. The support base 3 may have any shape as long as it has sufficient rigidity. For example, a U-shape or a shape obtained by partially cutting the support bases of the third and fourth embodiments described above can be used. .

  By applying the vibration power generation apparatus of the present invention described above as a power supply apparatus for a wireless sensor, it is possible to overcome problems related to power supply in the wireless sensor. Wireless sensors have already been put to practical use as vibration sensors for structural health monitoring such as highways, railways, buildings, and rotating machines, acceleration sensors, tire pressure monitoring sensors, and the like as sensors for measuring vibration.

1 Magnetostrictive member (magnetostrictive element)
2 Weight body 2a Weight body outer ring 2b Weight body joint cover 2c Weight body joint base 3 Support base 3a Support base housing 3b Support base joint cover 3c Support base joint base 3d Support base space 4 Ball joint (to ensure rotational freedom) Element)
4a Universal joint joint 4b Universal joint shaft 5 Magnetic coil 6 Magnet 7 Magnetic body (magnetic member)
8 Bracket (Force direction reversing means)
9 Amplitude limiting means 9a Protrusion 10 Fixing pin 11 Screw 12 Spring (elastic body)

Claims (6)

A support base that receives vibration from a vibration source, two rod-shaped magnetostrictive members made of a magnetostrictive material, and a weight that is connected between the magnetostrictive members to vibrate;
A rod-shaped or cylindrical magnetic member for connecting to the magnetostrictive member to form a loop-shaped magnetic circuit, a permanent magnet for supplying a bias magnetic field to the magnetic circuit, and a winding to be linked to the magnetic circuit Vibration power conversion means composed of a magnetic coil,
The two magnetostrictive members are fixed to the weight body via a member that secures a degree of freedom of rotation, and one end of the two magnetostrictive members is fixed so that the two magnetostrictive members are substantially linear. A vibration that is fixed to a support base via a member that secures a degree of freedom of rotation, and generates power when the magnetostrictive member of the vibration power conversion means expands or contracts with the vibration of the weight body. Power generation device.   In the vibration power conversion means, the total length of the vibration portion composed of the magnetostrictive member and the weight body is slightly longer than the interval between the two fixed positions of the support base, and the 2 of the support base and the magnetostrictive member is 2. The vibration power generator according to claim 1, wherein an angle formed by a central axis connecting a fixed position of the portion and the magnetostrictive member is greater than 0 degrees and smaller than 5 degrees.   The oscillating power conversion means has a structure in which tension applied to both ends of the magnetostrictive member is inverted inside the magnetostrictive member and transmitted to the magnetostrictive element so that a compressive force mainly acts on the magnetostrictive element. The vibration power generator according to claim 1.   2. The vibration power generation apparatus according to claim 1, wherein the vibration power conversion unit includes an amplitude limiting unit formed of an annular shape, a cylindrical shape, or a plurality of protrusions around the weight body.   The amplitude limiting means is an annular or cylindrical shape, and the amplitude limiting means includes one or more protrusions on a surface that contacts the weight body, or the amplitude limiting means includes a plurality of protrusions and the The vibration power generator according to claim 4, further comprising one or more protrusions having different distances from a central axis connecting fixed points of the support base. The vibration power converting means arranges the magnetostrictive member in a substantially horizontal direction and suspends the weight body by an elastic body to cancel the drooping of the weight body due to gravity, and the weight when there is no external vibration The vibration power generation apparatus according to claim 1, wherein an initial position of a body is held on the central axis.