JP2015126584A - Power generation mechanism and sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology that extends a frequency region that enables vibration power generation and thereby effectively conducts power generation.SOLUTION: A vibration power generation device 10 includes: a housing part 20; a power generator 30; a vibration impact part 40; an elasticity adjustment part 50; and a spring 60. The vibration power generation device 10 is installed on a crosstie 90 etc. of a rail track. The power generator 30 is a magneto-striction type power generator and is subject to an impact caused by the vibration impact part 40 to generate power. An impact frame 41 of the vibration impact part 40 is a beam shaped elongated quadratic prism formed by a stainless steel material. An end part of the impact frame 41 at the right side in a figure is rotatably attached to a second support pillar 23 by a rotary shaft 42. An impact part 43 is attached to the other end part of the impact frame 41 (a free end side at the left side in the figure) facing upward. A weight 44 is attached to the impact frame 41. A spring 60 is attached so as to connect the impact frame 41 with a spring support frame 51.

Description

  The present invention relates to a power generation mechanism and a sensor, and more particularly to a power generation mechanism that generates power by vibration and a sensor using the power generation mechanism.

  In the field of railways and traffic, there are many places where vibrations occur, and technologies that use such vibrations have been sought. For example, there is a technique for converting vibration into electric power (hereinafter also referred to as “vibration power generation”). As such a technique, there is a technique in which electric power is generated by a piezoelectric power generation mechanism, and a technique for trying to generate power with high efficiency against a force acting from outside due to piezoelectricity caused by vibration (for example, Patent Document 1 and Patent Document). 2).

  In general, as disclosed in Patent Document 1 and Patent Document 2, a vibration power generation system has a so-called one-degree-of-freedom structure, and generates power by increasing one natural frequency. Here, FIG. 6 shows a model of the vibration system and an expression relating to the natural frequency. FIG. 6A relates to a one-degree-of-freedom system, and FIG. 6B relates to a two-degree-of-freedom system.

  As can be seen from Equation (1) in FIG. 6A, in the one-degree-of-freedom system, the natural frequency is changed by changing the mass m and the spring constant k. However, in order to cope with a low frequency, it is necessary to lengthen the spring portion or enlarge the weight.

  In addition, “Research of Wideband Vibration System of Energy Harvest System for Wireless Sensor (Non-Patent Document 1)” discloses a power generation apparatus that uses a two-degree-of-freedom system and supports a plurality of vibration frequencies. However, the technique of the document has two natural frequencies, but even if the frequency is shifted even at 1 Hz, power generation cannot be performed (sensing becomes impossible). Here, the two-degree-of-freedom system of the technique disclosed in Non-Patent Document 1 is generally shown by a simplified diagram shown in FIG. 6B below, and the natural frequency is expressed by Equations (2) and (3) in the drawing. ). Using these simultaneous equations, two masses (m1, m2) and spring constants (k1, k2) are determined.

JP 2006-158112 A JP-A-11-136964 Kibong Han et al., `` Research of Wideband Vibration System of Energy Harvest System for Wireless Sensor '', International Journal of Emerging Technology and Advanced Engineering, Volume 2, 12 December 2012, p.49-53 Hideya Kaji et al., “Fundamental study on simple train vibration monitoring method using vibration power generation device”, August 2012, 67th Annual Scientific Lecture Meeting Collection VI, p. 515-516 "Analysis of vibration generated on railway tracks", July 1970, Proceedings of the Society of Civil Engineers No. 179

  By the way, it is known that the natural vibration frequency of sleepers and roadbeds changes depending on the axle distance of the train and the speed at which the wheels pass through the sleepers (for example, see Non-Patent Document 3).

  When a vibration power generation device of a one-degree-of-freedom system is attached, power generation is performed with only one natural frequency, and power generation under various conditions is difficult, and introduction of a new technology has been demanded. Further, in order to generate power in a wide frequency range, it is necessary to attach a device having a natural frequency suitable for each frequency. Furthermore, it is necessary to investigate and adjust the natural frequency of sleepers according to the vehicle passing speed set in advance.

  This invention is made | formed in view of the above situations, Comprising: It is providing the technique which solves the said subject.

The power generation mechanism of the present invention is provided with a power generation unit that receives a mechanical external force and converts the external force into electric power, a beam-like vibration unit that swings due to vibration, and a free end of the vibration unit. Attached so as to connect a force acting portion that causes the mechanical external force to act on the power generation portion, a weight provided on the vibrating portion, the vibrating portion, and a member that is displaced in conjunction with an installation object. And an elastic member.
The power generation unit may be a magnetostrictive power generation device.
In addition, the shape of the tip of the force acting portion may have a shape that causes an external force to act on the power generating portion at a single point.
Moreover, the attachment mode of the elastic member may be adjustable.
Moreover, the attachment mode of the weight may be adjustable.
The sensor of the present invention includes the above-described power generation mechanism and a determination unit that detects a vibration state based on the power output from the power generation mechanism.

  ADVANTAGE OF THE INVENTION According to this invention, the technique which expands the frequency area | region which can be generated in vibration power generation, and can produce electric power effectively can be provided.

It is a figure which shows simply the structure of the vibration electric power generating apparatus based on this embodiment. It is a front view which shows the structure of the vibration electric power generating apparatus based on this embodiment. It is a right view which shows the structure of the vibration electric power generating apparatus based on this embodiment. It is a left view which shows the structure of the vibration electric power generating apparatus based on this embodiment. It is the figure which compared the electric power generation amount (electric storage amount) of this vibration electric power generating apparatus which concerns on this embodiment, and the vibration electric power generating apparatus of 1 degree of freedom system. It is the figure which showed the formula regarding the model and natural frequency of 1 degree-of-freedom system and 2 degree-of-freedom system concerning this embodiment.

  Next, modes for carrying out the present invention (hereinafter, simply referred to as “embodiments”) will be specifically described with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of a vibration power generation apparatus 10 according to the present embodiment. FIG. 2 is a front view of a structure in which the vibration power generation apparatus 10 is actually prototyped and a power generation experiment described later is performed. 3 is a right side view of the vibration power generation apparatus 10 corresponding to FIG. 2 (arrow X2 in FIG. 2). 4 is a left side view of the vibration power generation apparatus 10 corresponding to FIG. 2 (arrow X1 in FIG. 2).

  The vibration power generation apparatus 10 includes a housing unit 20, a generator 30, a vibration striking unit 40, an elastic adjustment unit 50, and a spring 60. The vibration power generation apparatus 10 is installed on a railroad sleeper 90 or the like of a track, and a vibration hitting unit 40 that is swung by vibration hits the generator 30. The power generator 30 is a magnetostrictive power generator, and generates power upon being hit by the vibration hitting unit 40.

  The casing unit 20 is fixed to a structure that actually vibrates, such as the sleepers 90, and the generator 30, the vibration striking unit 40, the elastic adjustment unit 50, and the spring 60 are arranged at predetermined positions. .

  Specifically, the housing part 20 is made of, for example, stainless steel, and includes a base part 21, a first support part 22, a second support part 23, and a generator support frame part 24.

  The base portion 21 is a rectangular plate-like member having a predetermined thickness in the drawing, and is fixed to a vibrating structure such as a sleeper 90. A first column portion 22 extending vertically is fixed to the left end portion of the base portion 21 in the figure. Similarly, a second support column 23 extending vertically is fixed to the right end of the figure.

  A generator support frame portion 24 extending to the second column portion 23 side is fixed to the upper end of the first column 22 with a predetermined length. The generator 30 is fixed to the generator support frame portion 24 so as to be suspended.

  In the range from the upper end of the second support column 23 to the substantially central portion in the vertical direction, the elastic adjustment unit 50 extending to the first support column 22 side is fixed so that the position can be adjusted. For position adjustment, as shown in FIG. 3, a plurality of height adjustment openings 25 are formed. The spring support frame 51 is shown as being fixed on the uppermost side with a solid line in FIG. 2, and is fixed on the lowermost side with a two-dot broken line.

  The elastic adjustment unit 50 is, for example, a stainless steel material, like the housing unit 20. In the elastic adjustment portion 50, a plurality of spring adjustment fixing holes 52 for attaching one end portion of the spring 60 are formed side by side at predetermined intervals. Here, six spring adjustment fixing holes 52 are formed.

  A vibration striking portion 40 is attached to a position slightly below the center in the up-down direction of the second support column 23 so as to be swingable up and down by a rotating shaft 42.

  The vibration striking part 40 includes a striking frame 41, a striking part 43, a weight 44, a position adjusting hole 45, and a spring slide part 46.

  The striking frame 41 is a beam-like elongated rectangular column formed of a stainless steel material, and an end portion on the left side of the drawing is attached to the second column portion 23 so as to be rotatable by a rotation shaft 42.

  A striking portion 43 is attached upward to the other end of the striking frame 41 (the free end on the left side in the drawing). The striking portion 43 preferably has a shape that contacts the generator at one point in order to apply a strong striking force to the generator. In this embodiment, the upper end is a cylindrical member having a hemispherical shape, but the upper end may be conical or triangular pyramid. A lower portion of the hitting portion 43 is fixed to the hitting frame 41. In the configuration of FIG. 2, the upper hemisphere portion of the hitting portion 43 is arranged so as to face the generator 30 (the hit portion 32) with the hitting frame 41 in a horizontal state. It may be arranged in an oblique state depending on the spring constant. When the striking frame 41 swings, the tip portion of the striking portion 43 hits the hit portion 32.

  Near the free end side of the striking frame 41, a weight 44 is attached in an exchangeable manner. Further, a plurality of position adjusting holes 45 penetrating in the lateral direction are formed at predetermined intervals on the side surface of the striking frame 41 at a predetermined position closer to the rotation shaft 42 than the weight 44 at predetermined intervals in the extending direction (lateral direction). Has been. In this way, the weight 44 can be adjusted in its mounting manner.

  A spring slide portion 46 used for fixing one end of the spring 60 is attached to the position adjusting hole 45. The spring slide part 46 is fixed to a desired position adjusting hole 45 by a bolt. An opening 47 for fixing one end of the spring 60 is formed in the upper portion of the spring slide portion 46.

  That is, the end portion of the spring 60 is fixed to the spring adjustment fixing hole 52 and the opening 47 of the spring slide portion 46. The initial length of the spring 60 can be adjusted by selecting the spring adjustment fixing hole 52 to be attached and the opening 47 of the spring slide portion 46, or by adjusting the height of the spring support frame 51. The constant can be adjusted, and the tilt of the batting frame 41 and the amount of movement of the tip portion, that is, the amount of movement of the batting portion 43 can be adjusted. Of course, it is also possible to replace the spring 60 itself. In this way, the attachment mode of the spring 60 can be adjusted.

  The generator 30 includes a coil part 31 and a hit part 32. The coil part 31 is fixed downward to the generator support frame part 24. The hit portion 32 is attached to the lower side of the coil portion 31. The coil part 31 is comprised with the electric power generating element which wound the copper wire in the coil shape around the outer periphery of the material called a magnetostrictive element. A magnetostrictive element is a member that generates electric power by a reverse magnetostriction effect (Villari effect) in which an electromotive force is generated in a coil wound around the outer periphery of a magnetostrictive material when a stress is applied from the outside to a material that exhibits inverse magnetostriction and a metal crystal strain is applied. Here, the hitting portion 43 oscillated by vibration hits the hit portion 32. An electromotive force is generated in the coil portion 31 by transmitting stress due to the impact to the coil portion via the hit portion. The generator 30 can output electric power by taking out this electromotive force.

  By the way, when a one-degree-of-freedom structure is employed, sufficient vibration cannot be obtained when a member corresponding to the striking portion 43 vibrates even slightly away from the natural frequency f. As a result, the force for striking the hit portion 32 is weakened, and the amount of power generation is reduced.

  Therefore, in the present embodiment, the above-described structure is adopted to widen the frequency of vibration that is favorable. Here, it is known that the band having a low frequency has a large amplitude width. The vibration power generation apparatus 10 uses the amplitude width.

バネ６０には復元力（ｋｘ）が作用し、錘４４の相対変位を小さくする力が発生するのでＦ＝−ｋｘと表される。よって、次の式（５）が成り立つ。ここで、ｍは錘４４の質量、ｕは静止地盤変位を示す。右辺の大きさは、慣性力と呼ばれ動く枕木９０を動かないものと仮定したときのみかけの力である。

When the vibration power generation apparatus 10 receives the vertical amplitude, a force F represented by the following expression (4) is applied to the beam (the striking frame 41) with the weight 44. Here, x is the amount of extension from the initial position of the spring 60 (the position in the state of zero vibration is regarded as zero elongation).

Since a restoring force (kx) acts on the spring 60 and a force for reducing the relative displacement of the weight 44 is generated, F = −kx is expressed. Therefore, the following equation (5) is established. Here, m represents the mass of the weight 44, and u represents the stationary ground displacement. The size of the right side is an apparent force when it is assumed that the moving sleeper 90, which is called inertial force, does not move.

  In this embodiment, in order to cope with a low frequency, the beam (striking frame 41) is slowly swung by reducing the force (restoring force) for returning the weight 44 to the original. As a result, it is possible to sufficiently hit the hit portion 32 of the generator 30 with a wideband frequency. That is, it is possible to favorably apply stress to the inside of the coil portion 31 (magnetostrictive element), and good power generation is possible.

As a reference example, a result of a power generation amount comparison test using the vibration power generation device of the one-degree-of-freedom system and the vibration power generation device 10 of the present embodiment is shown. As a test method, the apparatus is vibrated at an acceleration of 0.1 G with a shaker and generated by both apparatuses. The generated voltage was rectified by a rectifier circuit and stored in a capacitor for 30 seconds, and the stored voltage at that time was observed with an oscilloscope. After measuring the storage voltage,
Power generation amount ^{W (J) = CV 2/} 2
Calculated by
Here, C is a capacitor capacity (F), and V is a storage voltage (V).
The measured frequency is 1 Hz intervals from 2 Hz to 10 Hz.

  The mass of the weight 44 was 50 g. Accordingly, the spring 60 was selected and its mounting state was adjusted. As a comparison object, a vibration power generator of a vibration system with one degree of freedom having an equivalent weight was used. The weight 44 is assumed to be the above value because it is assumed that the weight is actually attached to the sleeper 90 or the like. If the weight is larger than that, the weight becomes larger and the other parts must be designed to withstand vibration. This is a practical range in terms of practical use. In addition, in the prototype of the vibration power generation apparatus 10 shown in FIGS. 2 to 4, the width is about 18 cm and the height is about 15 cm in FIG. 2, and generally falls within the allowable range that can be installed on a railway track. Yes. Further, it is clear that there is much room for further downsizing even when the weight 44 having the above-described mass is adopted in actual product production.

  The measured power generation amount for each frequency is shown in the graph of FIG. As shown in the figure, in the one-degree-of-freedom system, the power generation amount (storage amount) is large at 8 Hz assumed to be the natural frequency. However, it can be seen that the amount of power generation is reduced just by shifting 1 Hz, and the amount of power generation is zero at 2 to 5, 9, and 10 Hz, and the power generation range is very narrow. The power generation amount for 30 seconds is 92.5 μJ.

  On the other hand, in the vibration power generation apparatus 10 of the present embodiment in which the power generation possible area is widened, although there is a peak at 5 Hz, the power generation amount is not greatly reduced even when it is shifted. Compared to the one-degree-of-freedom system, it can be seen that power is generated more widely. The power generation amount for 30 seconds is 221.3 μJ.

  Note that the vibration power generation apparatus 10 according to the present embodiment is installed in the sleepers 90 or the like, and performs so-called vibration power generation by vibration accompanying the passage of a train. It can be used for applications such as transmitting predetermined data to an external monitoring device using the power obtained by power generation. In particular, in recent years, sufficient communication distance and communication quality can be ensured even with small output communication, and therefore sufficient communication can be performed even with the above power generation amount. Moreover, the usage method of driving a predetermined sensor is also possible.

  Further, the vibration power generation device 10 can also function as a sensor (detection device). For example, it can be used as a sensor that detects a cavity of a roadbed. When a cavity or the like is generated in the vicinity where the vibration power generation apparatus 10 is installed, it is assumed that the vibration state changes. It is assumed that the power generation amount of the roadbed cavity is increased by increasing the amplitude width of the sleeper 90 due to the cavity. Therefore, not only power generation but also cavity sensing becomes possible. The power generation amount may be continuously recorded, and if a different tendency occurs, it may be determined that there is a possibility of occurrence of a cavity and a warning may be output to a predetermined monitoring device.

  It can be applied to a device that monitors aging due to bridge vibration. It is thought that the amplitude of the bridge will increase due to aging, so that not only will the amount of power generation increase, but it will also be possible to sense aging.

  In addition, wireless transmission is also possible as the amount of power generation increases. In other words, if a communication device capable of communication is provided only when the amount of power generation increases due to hollowing out or aging as described above, transmission from the vibration power generation device 10 It can be determined that an abnormality may have occurred.

  Moreover, the vibration pattern shows the same tendency to some extent depending on the type of vehicle passing through. In the case of a railway, the passing vehicle can be identified, so the vibration generated by the passing vehicle shows a different pattern from the assumed vibration, and no change is seen in the vibration pattern of other vehicles In this case, it may be determined that there may be a problem with the vehicle.

  Further, the vibration power generation apparatus 10 can be used as a speed detector. When the train axle interval is L (m) and the power generation frequency of the vibration power generation apparatus 10 is f (Hz), the train speed V (m / second) can be calculated as V = L × f (m / second). When the train speed V (m / sec) exceeds a preset value set in advance or an allowable speed commanded from the outside, a warning output may be output as an excessive train speed.

  As described above, in this embodiment, the beam (striking frame 41) can be vibrated (oscillated) slowly by reducing the force (restoring force) for returning the weight to cope with a low frequency. As a result, power can be generated by applying stress at the striking portion 43 that swings with respect to the generator 30 at a wider frequency band.

  The present invention has been described based on the embodiments. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to combinations of these components, and such modifications are also within the scope of the present invention.

DESCRIPTION OF SYMBOLS 10 Vibration power generator 20 Case part 21 Base part 22 1st support | pillar part 23 2nd support | pillar part 24 Generator support frame part 25 Height adjustment opening 30 Generator 31 Coil part 32 Struck part 40 Vibration hit part 41 Strike frame 42 Rotating shaft 43 Strike portion 44 Weight 45 Position adjustment hole 46 Spring slide portion 50 Elastic adjustment portion 51 Spring support frame 52 Spring adjustment fixing hole 60 Spring 90 Sleeper

Claims (6)

A power generation unit that receives mechanical external force and converts the external force into electric power;
A beam-like vibrating part that swings due to vibration;
A force acting portion that is provided on the free end side of the vibrating portion, and causes the mechanical external force to act on the power generation portion in accordance with the swinging;
A weight provided in the vibrating portion;
An elastic member attached so as to connect the vibrating part and a member that is displaced in conjunction with an installation;
A power generation mechanism comprising:   The power generation mechanism according to claim 1, wherein the power generation unit is a magnetostrictive power generation device.   The power generation mechanism according to claim 2, wherein a shape of a tip of the force acting portion has a shape in which an external force is applied to the power generating portion at a single point.   The power generation mechanism according to any one of claims 1 to 3, wherein an attachment mode of the elastic member is adjustable.   The power generation mechanism according to any one of claims 1 to 4, wherein an attachment mode of the weight is adjustable. A power generation mechanism according to any one of claims 1 to 5,
And a determination unit that detects a vibration state based on electric power output from the power generation mechanism.

Images