JP4704093B2 - Vibration generator - Google Patents

Description

  The present invention relates to a vibration generator for small portable and mobile electronic devices in which a plurality of moving and integrated permanent magnets are vibrated or moved in a plurality of coils to increase a power generation voltage and power generation efficiency. It is.

  In the case of an emergency portable radio or the like, a portable radio that incorporates a rechargeable battery and a hand-driven generator is generally commercially available. In addition, an emergency flashlight or the like uses a vibration generator that charges a capacitor by generating an induced current by vibrating a permanent magnet in a coil. Further, as another example of generating power by vibrating the permanent magnet in a coil, the permanent magnet has a structure in which a plurality of permanent magnets are arranged in series, and the individual magnets arranged in series face each other with the same polarity. There is a vibration generator arranged as follows.

  In the hand-driven generator as described above, a member such as a handle and a gear for turning the generator other than the bearing of the rotating part of the generator main body and the main body is also required, and the size is increased and the number of parts is increased. There was a problem that the load of turning was large.

As an improvement measure, portable generators that generate power using vibrations or shocks caused by carrying around have been developed. As an example, there is a vibration generator used for an emergency flashlight or the like that vibrates a permanent magnet in a coil to generate an induced current, charges a capacitor, and turns on an LED (for example, Patent Document 1). .
FIG. 8 shows a copy of the cross-sectional view of the vibration generator shown in FIG.
As shown in FIG. 8, such a conventional vibration power generator includes a single movable magnet 10 disposed so as to have the same polarity as the fixed magnets 15 and 16, and a kind of magnetic spring, and the movable magnet 10. The electric power is generated by vibrating in one coil 20 arranged on the outer periphery. However, since both the magnet and the coil that contribute to power generation are composed of one piece, the power generation efficiency is low, and the generated voltage is low, so it is difficult to reduce the size. It was necessary to use a magnet, and there were problems in terms of cost and weight.

As another example of a conventional vibration generator, a plurality of permanent magnets are arranged in series, and a plurality of coils are arranged on the outer periphery of the plurality of permanent magnets arranged in series. There is a vibration generator in which the same poles face each other (for example, Patent Document 2).
According to FIG. 2, FIG. 6, and paragraph 0007 of Patent Document 2, the plurality of permanent magnets arranged in series are not mechanically constrained and integrated, and are configured to maintain a mutual distance by repulsion. Yes.
The invention of Patent Document 2 has a configuration similar to the present invention at first glance, but the magnetic flux distribution is completely different from the present invention. There is non-uniformity in the magnetic distribution of an actual magnet, and it is very unstable magnetically when the same poles are opposed to each other. Therefore, since the invention of Patent Document 2 is not mechanically constrained and integrated, the repulsive force is non-uniform and the central axes of the individual magnets do not coincide with each other. It is difficult to vibrate.
JP 2002-281727 A JP 2005-033917 A

  The problem to be solved is that it is difficult to construct a high-power, high-efficiency small portable generator with a low load for power generation and a high generated voltage.

  In the present invention, a plurality of permanent magnets magnetized in the length direction are integrated with the same poles facing each other with a minute distance, the change in magnetic flux distribution is made steep, and the direction of the magnetic flux is wound around the coil. The magnetic flux is locally high density, and a plurality of coils are arranged in series on the outer periphery of the integrated plurality of permanent magnets, and the coils have appropriate intervals and are alternately arranged. The structure is such that the winding direction is reversed, and a vibration generator that generates power by moving the integrated permanent magnet is configured.

  By adopting this configuration, a plurality of steep magnetic flux density change magnetic fields are generated, and the magnetic field change is repeatedly applied to a plurality of coils, as if multiple high-efficiency generators are connected in series. Since a large force is not required for moving the magnet in order to exert the effect, it is portable and compact, and high voltage and high efficiency power generation is possible with a short moving distance.

  The length of each coil is a position where a large part of the magnetic flux density distribution region of opposite polarity does not enter the same coil from the graph of the magnetic flux density calculation result by the magnetic field analysis of the same-pole opposed magnet shown in FIGS. In order to make the relationship, the length of each coil needs to be equal to or less than the length of a single magnet. Further, the experimental results of the coil width / magnet length and charging voltage shown in FIG. From the graph, the length of each coil is 70% to 90% of the length of the individual magnet. For this reason, power generation efficiency (charging voltage) becomes high. The optimum value is about 80%.

  From the graph of the magnetic flux density calculation result by the magnetic field analysis of the same-pole opposed magnets shown in FIG. 4 and FIG. When the distance between the magnets is sufficiently long, the area between the magnets is widened, but the peak value is lowered and the central part is depressed, and the total magnetic flux is also reduced. Therefore, it can be seen that there is an appropriate value for the distance between magnets of the same polarity.

  The appropriate value of the distance between the magnets of the same polarity is described in detail in Example 1. FIG. 10 is a graph showing experimental results of distance between magnets / magnet length and charging voltage. It is characterized by 10% to 40%. For this reason, power generation efficiency (charging voltage) becomes high. The optimum value is about 25%.

  As apparent from the graph of the magnetic pole density calculation result by magnetic field analysis and the positional relationship of the magnets and coils of the same-pole opposed magnet shown in FIG. 7, the inter-coil distance is determined from the relationship between the magnet length, the inter-magnet distance, and the coil length. Although calculated, there is an appropriate value for the distance between the coils. From the graph showing the experimental results of the distance between the magnets / the magnet length and the charging voltage shown in FIG. It is characterized by being 10% to 30% of the length of the magnet. For this reason, power generation efficiency (charging voltage) becomes high. The optimum value is about 20%.

  As described above, when the length of the magnet, the distance between the magnets and the coil length are determined, the distance between the coils is calculated. However, if the calculated result deviates from the vicinity of the optimum value, the length of the magnet, the distance between the magnets and the coil are calculated. It is necessary to redesign the length and the distance between the coils so that they are close to the optimum values.

  As is apparent from the practical configuration diagram of the present invention shown in FIG. 2, power is generated if there is a coil on the outer periphery of at least one movable magnet within a movable range of the movable magnet unit 10, so the number of coils is the number of movable magnets. More than the number is better. Also, from the viewpoint of product cost and output, magnets are more expensive than coils, and rare earth magnets are used for further miniaturization, so the number of magnets is reduced and the number of coils is increased. This is a more economical configuration and the output voltage is higher.

  Therefore, the number of coils is the same as the number of magnets or the number of magnets + 1 or more. With such a configuration, there is an advantage that the output voltage is high and an economic effect can be obtained.

  When the magnets having the same polarity are brought close to a minute distance, a large repulsive force is generated, and it is difficult to keep the distance between the magnets constant and to assemble. Therefore, in the present invention shown in FIG. 2, the permanent magnet is cylindrical, and the nonmagnetic fastening member is inserted into the hole of the thin cylindrical nonmagnetic magnet spacer having the same inner and outer diameter as the cylindrical magnet and fixed. Thus, a plurality of permanent magnets and a magnet spacer are integrated. For this reason, assembly is easy and high-precision movable magnet units can be mass-produced.

  In the present invention shown in FIG. 2, a non-magnetic cylindrical case and a non-magnetic coil spacer are integrated, and a plurality of coils are wound on the outer periphery of the non-magnetic cylindrical case so as to have an appropriate interval. The permanent magnet integrated in the inside of the non-magnetic cylindrical case is housed and arranged to be movable. For this reason, it is possible to mass-produce a vibration generator with a small number of parts, a high accuracy of the distance between the coils, easy assembly, and high accuracy.

  In addition, although it has been described that a plurality of coils are arranged in series so that the winding directions are alternately reversed, it is only necessary to configure the winding directions to be substantially alternately reversed. They may be wound in a direction and connected in series by alternately switching the winding start ends and winding end ends of adjacent coils.

  The coil used in the present invention can be used without any restrictions on the winding method and shape such as bobbin winding coil, air core coil, sheet coil and the like.

  Permanent magnets can also be used without any restrictions on the production methods such as cast magnets, sintered magnets, bonded magnets, plastic magnets, and materials such as ferrite, alnico, SmCo, NdFeB, and SmFeN. The shape of the permanent magnet can be used without any restrictions such as a rod shape, a cylindrical shape, or a disk shape.

  The buffer member 60 is provided for the purpose of mitigating the impact of the movable magnet unit 10 colliding with the case lid 31 and can be used without any restrictions such as porous rubber, plastic, urethane, etc. A spring or the like can also be used. Furthermore, the magnetic spring configuration disclosed in Patent Document 1 can also be used.

  Since the fastening member 40 is used for the purpose of mechanically integrating a plurality of magnets having the same poles facing each other with a minute distance, if the material is non-magnetic, not only the resin but also the repulsion of the magnet Since it is fastened against the force and exposed to the impact of a collision, a metal such as non-magnetic SUS can also be used. Further, W, Ni, Fe or W, Ni, Cu, Fe can be sintered. If the fastening member 40 is made of heavy metal, which is a binding metal material, the fastening member 40 has a specific gravity close to 20, and the kinetic energy at the time of movement is large, so that the amount of power generation is increased and the strength is improved.

  By causing a plurality of magnets to face each other with a minute distance between the same poles, the direction of magnetic flux is substantially orthogonal to the coil winding, and the power generation efficiency is improved. In addition, by generating multiple magnetic fields with steep changes in magnetic flux density and repeatedly applying magnetic field changes to multiple coils, it is as small as possible to demonstrate the effect of connecting multiple generators in series. Since a vibration generator with a high voltage and high efficiency can be configured even with a short moving distance, there is an advantage that it is possible to downsize the portable device. Furthermore, since a large force is not required for moving the magnet, power can be generated even with a slight force when carried by a person.

  The objective of inputting an image from a position outside the housing or as close to the end of the housing as possible was realized with the minimum number of components and without sacrificing the thickness of the optical system components.

  The overall configuration will be described with reference to FIG. The cylindrical movable magnets 11 and 12 are for the movable magnets 11 and 12 and nonmagnetic magnets so that the same poles face each other at appropriate intervals by a thin cylindrical nonmagnetic magnet spacer 50 having the same inner and outer diameters as the magnets. The non-magnetic fastening member 40 is inserted into the hole of the spacer 50 and fixed to constitute the movable magnet unit 10 in which a plurality of movable magnets and the magnet spacer 50 are integrated.

  The movable magnet unit 10 can freely move in a non-magnetic case 30 in the axial direction of the movable magnet unit 10. The coils 21 and 22 are arranged on the outer periphery of the case 30 at an appropriate interval and connected in series. The coils 21 and 22 are wound in opposite directions as shown in coil cross sections 21a and 21b and 22a and 22b. In addition, 21a and 22a are cross sections of the coil wound in the paper surface direction, and 21b and 22b are cross sections of the coil wound in the paper back direction.

  The case lid 31 is provided with a cushioning member 60 such as porous rubber, and the case lid 31 is fixed to the case 30 to mitigate the impact of the movable magnet unit 10 colliding with the case lid 31.

  Next, magnetic field analysis will be described. FIG. 5 shows the magnetic field analysis results of a single magnet, showing the direction and density of the generated magnetic flux. It can be seen that the magnetic flux generated at both poles of the magnet has few components perpendicular to the central axis of the magnet. On the other hand, in FIG. 3 which shows the magnetic field analysis result of the homopolar counter magnet according to the present invention, the density of the generated magnetic flux is high at the opposed portion of the two homopolar counter magnets and is perpendicular to the central axis of the magnet. It turns out that there are many ingredients. Furthermore, since the right-angle component of the magnetic flux reaches the outer periphery away from the central axis of the magnet, the magnetic flux is linked to the coil even if the coil is thick (peripheral direction), so the number of turns of the coil is increased. Even if the coil thickness is increased, the generated magnetic flux can be used effectively, and the amount of power generation can be increased.

  In power generation, as is known as Fleming's right-hand rule, when the direction of the magnetic field and the direction of motion are perpendicular to each other, current flows in a perpendicular direction. Therefore, the power generation efficiency is best when the moving direction of the magnet, the direction of the magnetic flux, and the coil winding direction are perpendicular to each other. In the present invention, the moving direction of the magnet, the direction of the magnetic flux, and the coil winding direction are substantially perpendicular to each other, and the power generation efficiency is the best.

  Next, the magnetic flux density calculation result by magnetic field analysis will be described. FIG. 4 is a graph of magnetic flux density calculation results by magnetic field analysis in the outer peripheral length direction of two permanent magnets facing the same pole according to the present invention, and FIG. 6 is a graph of a permanent magnet of a single magnet for comparison with the present invention. It is a graph of the magnetic flux density calculation result by a magnetic field analysis result. The horizontal axis of the graph indicates the length of one movable magnet as 1 (reference). FIG. 4 and FIG. 6 are graphs showing the magnetic flux density distribution of the component perpendicular to the magnet central axis of the magnetic flux on the outer surface of the magnet in the magnetic field analysis results analyzed in FIG. 3 and FIG.

In power generation by electromagnetic induction, the electromotive force due to the change in magnetic flux in the coil is expressed by the following equation according to Faraday's law.
-E = N * dφ / dt
N: number of turns of coil φ: magnetic flux (wb) t: time (s)
From the electromotive force equation, when the number of turns of the coil is constant, the electromotive force increases as the amount of change of the magnetic flux with respect to time increases. Therefore, the steeper change in magnetic flux density causes the magnet to move at the same speed. In this case, the power generation capacity is high.

  Comparing the graphs of FIGS. 4 and 6 from the viewpoint of the formula of the electromotive force, the peak value of the magnetic flux density of the homopolar facing magnet according to the present invention is remarkably higher than that of the single magnet, and the change of the magnetic flux density is steep. It is clear that the range of high magnetic flux density is wide. Accordingly, since the total magnetic flux is significantly different from that of a single magnet, when the movable magnet unit of the present invention is moved, dφ / dt is increased, and high power generation is possible.

  FIG. 7 shows a graph of the magnetic flux density calculation result by magnetic field analysis and the positional relationship of magnets and coils in the case of three homopolar facing magnets in order to perform the optimum design for the practical configuration of the present invention. As described above, the horizontal axis shows the magnetic flux density distribution by three homopolar facing magnets with reference to one movable magnet.

  As can be seen from FIG. 7, when the length of one coil becomes longer than the length of one magnet + the distance between the magnets, it enters the coil up to the region of the magnetic flux distribution having the opposite polarity. It is clear that the actual output voltage will decrease, and in order to prevent the region of magnetic flux distribution of reverse polarity from entering one coil, the length of one coil is a magnet. Must be shorter than one length + distance between magnets. The experimental results will be described in detail in Examples, and the optimum value of the length of one coil is about 80% of the length of one magnet.

Similarly, the optimum value of the distance between the magnets of the same pole is about 25% of the magnet length, and the optimum value of the distance between the coils is about 20% of the magnet length. However, when there are three or more magnets, if the length of one coil, the distance between the magnets of the same polarity, and the distance between the coils are determined independently, a phase difference occurs in the generated voltage between the coils, and the opposite phase When this voltage is generated, the output voltage decreases.
(Length of one magnet) + (Distance between magnets of the same pole) = (Length of one coil) + (Distance between coils)
It is necessary to. In the case of two magnets and three or less coils, a large phase difference does not occur, so it is not necessary to use the relational expression, and the coil length, the distance between magnets, and the optimum distance between coils may be set. When the number of coils is four or more with two magnets, the phase difference increases, so that the above relational expression is satisfied.

  Up to this point, a configuration for explaining the principle of the present invention has been shown. FIG. 2 shows a practical configuration of a vibration generator as a product according to the present invention. The basic configuration is the same as in FIG. 1, but the coil length, the distance between the magnets, and the distance between the coils are designed to meet the optimum design conditions, and a cylindrical movable magnet magnetized in a relatively short length direction is used. A plurality of coils having the same poles and integrated with a nonmagnetic magnet spacer 50 facing each other at an optimum distance to form a movable magnet unit 10 and a nonmagnetic material such as a resin and a cylindrical case and an optimum value interval Coil integrally formed with a case made of a coil in which windings are wound so that the winding direction of a plurality of adjacent coils is opposite to each other. The movable magnet unit 10 is housed inside the unit 20 and arranged to be movable. Since the amount of power generation can be increased as the number of coils increases, the number of coils that can be arranged in the moving range of the movable magnet unit 10 is set. By shortening one movable magnet, the pitch of the magnetic flux change can be shortened, aiming at the cascade connection effect of the multi-stage generator, and a small vibration generator capable of generating a high voltage can be obtained.

  FIG. 1 is a cross-sectional view showing the fundamental configuration of the vibration generator of the present invention, and a prototype and an experiment were conducted using this configuration. The movable magnet is a cylindrical sintered magnet of NdFeB and is magnetized in the length direction. The magnet has an outer diameter of 8 mm, an inner diameter of 2 mm, and a length of 10 mm. Further, the length of the case 30 was set so that the moving distance of the movable magnet unit 10 was 100 mm.

  First, in order to investigate the optimum value of the coil length, the distance between the magnets is set by the resin magnet spacer 50 having a thickness of 2.5 mm, and the movable magnet unit 10 is formed. It was changed to 13 mm. The number of turns of the coils 21 and 22 was 50, and the winding directions were opposite to each other and were connected in series.

  The generator 01 prototyped with the above-described vibration generator configuration is shaken for 30 seconds, the generated electromotive force is charged by the charging circuit 80 shown in FIG. 12, and the amount of power generated by the coil length is evaluated by measuring the charging voltage. did.

  The result of the experiment is shown in FIG. The horizontal axis represents the ratio of the coil length based on the length of the magnet. According to the graph shown in FIG. 9, the length of each coil is preferably in the range of 70% to 90% of the length of the individual movable magnet. The optimum value is about 80%.

  Next, in the same manner as described above, in order to investigate the optimum value of the distance between the permanent magnets facing each other with the same polarity, the coil length is 8 mm, the distance between the coils is 2 mm, and the number of turns of the coils 21 and 22 is 50. The directions were opposite to each other and connected in series. With the above configuration, the change in power generation amount due to the distance between the permanent magnets was evaluated by measuring the charging voltage when the distance between the magnets was varied between 0.5 and 4.0 mm. In the same charging experiment, the prototype generator 01 was shaken for 30 seconds, and the generated electromotive force was charged by the charging circuit 80 shown in FIG. 12, and the charging voltage was measured.

  The result of the experiment is shown in FIG. The horizontal axis is based on the length of the magnet. From the graph shown in FIG. 10, the distance between the opposing permanent magnets is preferably in the range of 10% to 40% of the length of the single magnet. The optimum value is about 25%.

  Next, in order to investigate the optimum value of the distance between the coils, the distance between the permanent magnets is set to 2.5 mm, the coil length is 8 mm, the number of turns of the coils 21 and 22 is 50, and the winding direction is the same as above. Reversed and connected in series. By measuring the charging voltage when the distance between the coils was changed between 1 mm and 4 mm, the change in the amount of power generation due to the distance between the coils was evaluated. The charging experiment and the charging circuit are the same as described above.

  The result of the experiment is shown in FIG. The horizontal axis is based on the length of the magnet. From the graph shown in FIG. 11, the distance between the coils is preferably in the range of 10% to 30% of the individual magnet length. The optimum value is about 20%.

  As described above, when the length of the movable magnet is determined for the vibration generator of the present invention from a series of experiments, the coil length, the distance between the magnets, and the distance between the coils are set to optimum values, and the detailed specifications are followed to meet the required specifications. Optimal design is possible.

  In the configuration of the conventional vibration generator shown in FIG. 8 (however, the fixed magnets 15 and 16 are not used and the moving distance of the magnet is 100 mm), the magnet has the same outer diameter φ8 mm and inner diameter as the embodiment of the present invention. In a similar charging experiment when the diameter was 2 mm, the length was 20 mm, the length of the coil was 20 mm, and the number of turns was 100, the charging voltage was 40% or less of the present invention. Therefore, the effect of the present invention was demonstrated.

  As described above, according to the vibration generator according to the present invention, it has a simple structure, is excellent in mass productivity, can generate power even with a small force and a small moving distance, and has a high voltage, high efficiency, and portable electronics. It can be used as a power source and a charger for devices and communication devices.

It is sectional drawing which showed the fundamental structure of the vibration generator concerning this invention. Example 1 It is sectional drawing which showed the practical structure of the vibration generator concerning this invention. It is a magnetic field analysis result of the same-pole opposing magnet concerning this invention. It is a graph of the magnetic flux density calculation result by the magnetic field analysis of the same-pole opposing magnet concerning this invention. It is a magnetic field analysis result of a single magnet. It is a graph of the magnetic flux density calculation result by the magnetic field analysis of a single magnet. It is a graph of the magnetic flux density calculation result by the positional relationship of a magnet and a coil in the case of three same-pole opposing magnets concerning this invention, and a magnetic field analysis. (Patent document 1) It is sectional drawing of the vibration generator which copied FIG. 6 is a graph showing experimental results of coil length / magnet length and charging voltage in Example 1. It is a graph which shows the experimental result of the distance between magnets / magnet length in Example 1, and a charging voltage. It is a graph which shows the experimental result of the distance between coils / magnet length and charge voltage in Example 1. FIG. FIG. 3 is a charging circuit diagram according to the first embodiment.

Explanation of symbols

01 Generator 10 Movable magnet unit 11, 12, 13 Movable magnet 15, 16 Fixed magnet 20 Coil unit integrated with case 21, 22 Coil 21a, 22a Cross section of coil wound in paper direction 21b, 22b In paper back direction Winding coil cross section 30 Case 31 Case lid 40 Fastening member 50 Magnet spacer 60 Buffer member 70 Coil spacer 80 Charging circuit

Claims (6)

A plurality of permanent magnets integrated with the same poles facing each other;
A plurality of coils arranged so as to have an interval on the outer periphery of the plurality of permanent magnets, and configured so that the winding direction is alternately reversed,
A vibration generator that generates electricity by moving the plurality of permanent magnets,
The vibration generator according to claim 1, wherein the length of the coil is 70% to 90% of the length of the permanent magnet. A magnet spacer is disposed between the plurality of permanent magnets.
The vibration generator according to claim 1. The vibration generator according to claim 2 , wherein the interval between the permanent magnets adjacent via the magnet spacer is 10% to 40% of the length of the permanent magnet. The vibration generator according to any one of claims 1 to 3, wherein a distance between the coils is 10% to 30% of a length of the permanent magnet. The number of the coils, the vibration generator according to any one of claims 1 to 4, characterized in that a number plus one or more same number or a permanent magnet, the permanent magnet. 6. The vibration generator according to claim 2 , wherein the shape of the permanent magnet and the shape of the magnet spacer are cylindrical shapes having the same diameter.

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