JP5798654B2 - Leaf spring and vibration generator for vibration generator - Google Patents

Description

  The present invention relates to a leaf spring used for a vibration generator, and in particular, uses a leaf spring for a vibration generator having a structure excellent in durability and contributing to improvement of power generation efficiency of the vibration generator, and the leaf spring. It relates to a vibration generator.

  When the magnet is vibrated so as to pass through the conductive coil, an induced current is generated in the coil and an electromotive force is generated. As an example of utilizing this principle, there is an electromagnetic induction type vibration generator using a leaf spring. Such a vibration generator can generate electric energy based on vibration energy of the external environment.

  Furthermore, by using a vibration generator, it is possible to generate electric energy while eliminating the need for power supply by a power cable or a battery. From this point of view, vibration generators are expected to be used in many applications where economic advantages or operational advantages are expected. And as a prior art of the vibration generator using a leaf | plate spring, there exists what aimed at the improvement of energy efficiency (for example, refer patent document 1).

  As shown in FIG. 2, each of the springs has a spiral structure, and a plurality of spiral arms includes an inner annular end in the radial direction and an outer annular end in the radial direction. A structure extending between the ends is disclosed. And by using the leaf | plate spring provided with such a structure, the mass of a movable magnetic core combination body can be maximized, and output electric power can be increased.

Japanese Translation of PCT International Publication No. 2010-525779

However, the prior art has the following problems.
The leaf spring used in the vibration power generator has a function of suppressing displacement due to a lateral force corresponding to the plane of the leaf spring, compared to displacement in the vibration direction, which is a direction perpendicular to the plane of the leaf spring. In order to extend the life of the leaf spring, it is important to perform a structural analysis that can reduce stress concentration with respect to vibration displacement of the leaf spring and increase durability.

  Furthermore, the power generation efficiency of the vibration generator can be improved by reducing the gap between the permanent magnet and the coil. Therefore, from this point of view, by reducing the stress concentration, structural analysis that suppresses the lateral vibration of the leaf spring is important.

  However, Patent Document 1 does not mention anything about the structure of a leaf spring for improving durability or suppressing lateral shaking.

  The present invention has been made to solve the above-described problems, and is for a vibration generator having a structure capable of enhancing durability and suppressing lateral vibration perpendicular to the vibration direction. An object is to obtain a leaf spring and a vibration generator.

  The leaf spring for a vibration generator according to the present invention is used in a vibration generator that obtains an electromotive force by displacing a permanent magnet in a coil due to vibration, and holds either the permanent magnet or the coil. Plate springs, starting from the center of the leaf spring, with three or more spiral slits from the start to the outer periphery, and the closer to the end from the start, the notch width of each slit Is narrow and the spring width is widened.

  The vibration generator according to the present invention is a vibration generator that obtains an electromotive force by displacement of a permanent magnet in a coil due to vibration, and uses either the permanent magnet or the coil by using the leaf spring of the present invention. Is what is held.

  According to the present invention, a plate having a structure in which three or more spiral slits are provided from the center of the leaf spring toward the outer periphery, and the width of the slit becomes narrower toward the outer periphery and the spring width becomes wider. By adopting the spring, it is possible to obtain a leaf spring for a vibration generator having a structure capable of enhancing durability and suppressing lateral shaking perpendicular to the vibration direction.

It is a schematic sectional drawing for demonstrating the structure of the vibration generator in Embodiment 1 of this invention. It is a figure which shows the structure of the leaf | plate spring in Embodiment 1 of this invention. In Embodiment 1 of this invention, it is the figure which showed the simulation conditions for analyzing a stress and a frequency regarding leaf springs with various different shapes and configurations. It is a simulation result by the leaf | plate spring of various conditions in Embodiment 1 of this invention, and is the figure which showed the stress and frequency transition specifically ,. It is the figure which showed the stress distribution analysis result for verifying the effect of the drop shape of the slit termination | terminus in Embodiment 1 of this invention.

In the present invention, as a structure of a leaf spring used for a vibration generator, three or more spiral slits are provided from the center of the leaf spring toward the outer periphery, and the notch width of each slit is narrowed toward the outer periphery, And it has the technical feature of making a spring width wide. By providing such technical features, the following effects can be obtained.
(Effect 1) The stress generated in the leaf spring due to vibration can be reduced, and the durability of the leaf spring itself can be enhanced.
(Effect 2) As the stress is reduced, the lateral vibration can be suppressed, the gap between the permanent magnet and the coil can be reduced, and the power generation efficiency of the vibration generator using the leaf spring of the present invention can be improved. it can.

Furthermore, by providing the following additional features, it is possible to further improve durability and power generation efficiency.
(Additional feature 1) The slit end portion at the outer peripheral portion has a drop shape tangent to the slit and having a slit width widened toward the outer peripheral side.
(Additional feature 2) If necessary, a laminated structure using a plurality of leaf springs is adopted.

  A preferred embodiment of a leaf spring for a vibration generator according to the present invention having such technical features will be described in detail below with reference to the drawings.

Embodiment 1 FIG.
Before describing the structure of the leaf spring of the present invention, first, the role of the leaf spring used in the vibration generator will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view for explaining the structure of the vibration power generator according to Embodiment 1 of the present invention. The vibration generator according to the first embodiment shown in FIG. 1 includes permanent magnets 1a and 1b, a coil 2, leaf springs 3a and 3b, guide rods 4a and 4b, magnetic spring portions 5a and 5b, a frame 10, and a top plate 11. The upper plate 12 for magnet attachment, the middle plate 13, the lower plate 14 for magnet attachment, the bottom plate 15, and the frequency adjustment mechanism section 16 are provided. Here, the description will focus on the portions related to the leaf springs 3a and 3b.

  In FIG. 1, columnar or cylindrical permanent magnets (hereinafter referred to as magnets) 1a and 1b are arranged so as to face the same pole. Further, the coil 2 surrounds the magnets 1a and 1b. Here, the coil 2 is fixed to the intermediate plate 13, and the magnets 1a and 1b arranged in the coil 2 vibrate in the axial direction, whereby electric energy is generated.

  Further, the magnet 1a is connected to the magnetic spring portion 5a via the guide bar 4a, and an intermediate portion of the guide bar 4a is held by the plate spring 3a. Similarly, the magnet 1b is connected to the magnetic spring part 5b via the guide bar 4b, and the intermediate part of the guide bar 4b is held by the leaf spring 3b.

  Here, the leaf springs 3a and 3b support both ends of the movable portion including the magnets 1a and 1b and the guide rods 4a and 4b, and the vibration direction (the axis of the permanent magnet) is a direction perpendicular to the plane of the leaf springs 3a and 3b. Direction), and has a function of suppressing displacement with respect to a lateral force corresponding to the plane of the leaf springs 3a and 3b.

  Therefore, a specific structure of the leaf spring of the present invention capable of enhancing durability and suppressing lateral shaking will be described with reference to the drawings. The leaf springs 3a and 3b have the same configuration, and will be described as the leaf spring 3 in the following description. FIG. 2 is a diagram showing a configuration of the leaf spring 3 according to Embodiment 1 of the present invention. More specifically, FIG. 2 (a) is a plan view of the leaf spring 3, and FIG. 2 (b) shows an enlarged view of the lower right portion of FIG. 2 (a).

  As shown in FIG. 2A, the leaf spring 3 according to the first embodiment is provided with three spiral slits 31 (1) to 31 (3) from the center of the leaf spring toward the outer periphery. Yes. Further, each of the slits 31 (1) to 31 (3) has a drop shape 32 (1) to 32 (3) in which the slit width is widened to the outer peripheral side in a tangent to the slit at the slit terminal portion in the outer peripheral portion. Have.

Further, the three dimensions shown in FIG. 2B mean the following contents.
Ls: Notch width at the start (center side) of the slit Le: Notch width at the end (outer periphery) of the slit Ws: Spring width

Here, the notch width of each of the slits 31 (1) to 31 (3) in the first embodiment is configured such that the starting end is the widest, becomes narrower as it approaches the outer periphery, and becomes the narrowest at the end. In the following description, the slit notch width ratio U is
U = Ls / Le
It stipulates. When U = 1, the spring width Ws is constant.

FIG. 3 is a diagram showing simulation conditions for analyzing stress and frequency for leaf springs of various different shapes and configurations in the first embodiment of the present invention. The simulation analysis was performed for the following four patterns.
Pattern A: A configuration in which one leaf spring having a plate thickness t = 0.5 mm is disposed at each end of the movable portion. Pattern B: A leaf spring having a plate thickness t = 0.25 mm is disposed at each end of the movable portion. Configuration in which two sheets are stacked and arranged Pattern C: Configuration in which three plate springs having a plate thickness t = 0.16 mm are stacked and arranged on both ends of the movable portion Pattern D: Plate on each of both ends of the movable portion A configuration in which five leaf springs having a thickness t = 0.1 mm are stacked and arranged.

Then, for each of the patterns A to D, simulation was performed with the slit notch width ratio U being U = 1, U = 1.5, and U = 2. The following conditions are common to all patterns.
External dimensions: 62 mm
Notch termination dimension: 1.0 mm
Spring width: 2.9 mm (when U = 1)

  FIG. 4 is a simulation result of leaf springs under various conditions according to the first embodiment of the present invention. Specifically, FIG. 4 is a diagram showing changes in stress and frequency when the slit notch width ratio U is changed. It is. Further, in FIG. 4, in order to clarify the transition, simulation results for U values other than the three conditions of U = 1, U = 1.5, and U = 2 shown in FIG. I added. Note that the stress is obtained as a forced displacement as a value when displaced 5 mm in the axial direction.

The following points became clear from the simulation results of FIG.
<Stress analysis results>
-The stress decreases as the number of stacked layers increases.
However, when the number of laminated sheets is changed from 1 to 2, the effect of reducing the stress is large, but the effect of reducing the stress is small even if the number is increased from 2 to 3 or 5. Therefore, considering the manufacturing cost and ease of manufacturing, a structure with two stacked sheets is appropriate.
-Regarding the slit notch width ratio U, the effect of significant stress reduction is obtained by setting U = 1 to U = 1.1. On the other hand, the stress is substantially equal between U = 1.1 and U = 2. However, as U is larger, the stress distribution tends to disperse and the strength is advantageous.
・ Summarizing the results of FIG. 4, stress relaxation can be realized by setting the slit notch width ratio U to 1.1 or more, and furthermore, by adopting a laminated structure, U = 1 and a single-sheet structure On the other hand, it was found that the stress can be reduced by about 65%.

<Frequency analysis results>
・ The frequency decreases as the number of stacked layers increases. In this simulation, the plate thickness t = 0.5 mm, but it can be adjusted to the desired frequency by appropriately selecting the plate thickness and the number of stacked layers according to the resonance frequency in the usage environment. Is possible.
-As the slit notch width ratio U increases, the frequency slightly decreases. However, by increasing the number of stacked layers, the tendency of the frequency to decrease is also suppressed.

Next, the effect of the drop shape provided at the terminal portion will be described based on the stress distribution analysis result. FIG. 5 is a diagram showing a stress distribution analysis result for verifying the effect of the drop shape at the end of the slit in the first embodiment of the present invention. The four diagrams A1, A2, B1, and B2 in FIG. 5 show the following contents, respectively.
A1: Stress distribution when pattern A, U = 1 does not have a drop shape at the end A2: Stress distribution when pattern A, U = 1.5 has a drop shape at the end B1 : Stress distribution when pattern B, U = 1 and no end drop shape is provided B2: Stress distribution when pattern B, U = 1.5 is provided with end drop shape

  Comparing A1 and A2 in the pattern A, it can be seen that the stress concentration at the terminal end (especially, refer to the arrow portion illustrated in A1) is relaxed by providing the drop shape. Further, in pattern B, the stress itself relating to one leaf spring is less than that in pattern A, so that it is not as prominent as pattern A, but similarly, the state where the stress concentration at the end is relaxed can be confirmed.

  As described above, according to the first embodiment, three or more spiral slits are provided from the center of the leaf spring toward the outer periphery as the leaf spring used in the vibration power generator, and the notch width of each slit is set. The closer to the outer periphery, the narrower and the wider the spring. In particular, by forming the slit so that the slit notch width ratio U is 1.1 or more, the stress can be greatly reduced as compared with the case of U = 1. As a result, a leaf spring excellent in durability can be realized.

  Further, as an additional feature, a drop shape is provided at the slit end portion in the outer peripheral portion. With this structure, stress concentration at the end of the slit can be relaxed, and durability can be further improved. Further, as a further additional feature, by adopting a configuration in which a plurality of leaf springs are stacked, it is possible to reduce the stress associated with one leaf spring.

  As a result of relaxing the stress, an effect of suppressing displacement with respect to a lateral force is also obtained. Therefore, the gap between the permanent magnet and the coil can be reduced, and a vibration generator with high power generation efficiency can be realized. Specifically, by adopting the leaf spring according to the present invention, the lateral displacement can be suppressed to 1/50 or less with respect to the axial displacement. For example, when the gap between the permanent magnet and the coil can be 0.5 mm compared to the case where the gap between the permanent magnet and the coil is 1.5 mm, the electromotive force can be improved by about 35%.

  In the above-described embodiment, the case where the spring width is formed so as to gradually increase in the radial direction from the center to the outer periphery of the leaf spring has been described. It is not limited to a simple configuration. Similar effects can be obtained by forming slits so that the slit interval is constant instead of gradually increasing the spring width.

  1a, 1b Permanent magnet (magnet), 2 coils, 3a, 3b leaf spring, 31 slit, 32 drop shape.

Claims (6)

A leaf spring for a vibration generator that is used in a vibration generator that obtains an electromotive force by displacing a permanent magnet in a coil by vibration, and holds either the permanent magnet or the coil,
Three or more spiral slits are provided starting from the center of the leaf spring toward the outer periphery that is the end, and the notch width of each slit becomes narrower as it approaches the end from the start. Formed leaf spring for vibration generator. The leaf spring for a vibration generator according to claim 1,
The leaf spring is formed such that the slit interval is constant or the spring width is gradually increased in the radial direction from the center toward the outer periphery. Leaf spring for machine. The leaf spring for a vibration generator according to claim 1 or 2,
A leaf spring for a vibration generator is formed at the end of each slit with a drop shape with a notch width expanded to alleviate stress concentration. The leaf spring for a vibration generator according to any one of claims 1 to 3,
A plate spring for a vibration generator formed by laminating two or more plate springs. A leaf spring for a vibration generator according to any one of claims 1 to 4,
The slit notch width at the start end is Ls, the slit notch width at the end is Le, and the slit notch width ratio U is U = Ls / Le
Each of the slits is formed so that the slit notch width ratio U is 1.1 or more and 2 or less. A vibration generator that obtains an electromotive force by displacement of a permanent magnet in a coil by vibration,
Either of the said permanent magnet or the said coil is hold | maintained using the leaf | plate spring of any one of Claim 1 to 5. Vibration generator.

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