Vibration generator
The vibration generator facilitates easy adjustment of resonant frequency through a modular weight system, addressing the inefficiencies of existing generators by enabling efficient power generation and frequency detection across various structures.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- 西野 朋季
- Filing Date
- 2024-12-23
- Publication Date
- 2026-07-03
AI Technical Summary
Existing vibration generators struggle to efficiently generate electrical energy from weak vibrations and require dedicated designs for specific vibration frequencies, making them costly and time-consuming to implement.
A vibration generator with a frame, damper portion, vibration unit, and magnetic circuit that allows easy adjustment of resonant frequency by changing the mass and number of weights attached to the weight holder, enabling resonance at desired frequencies.
Enables easy modification of resonant frequency, allowing efficient power generation from vibrations and detection of specific frequencies without the need for custom designs, reducing costs and time.
Smart Images
Figure 2026110927000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a vibration generator.
Background Art
[0002] A vibration generator used for ambient power generation, called energy harvesting, is known and described in Patent Document 1. The vibration generator described in Patent Document 1 is an electromagnetic induction generator having a housing, an elastic member fixed to the housing, a vibrator supported by the elastic member and having a coil inside, and a group of magnets arranged so as to sandwich the coil. The electromagnetic induction generator generates an electromotive force in the coil due to a time change in the magnetic flux linked to the coil by the vibration of the vibrator, thereby generating electricity.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] Vibrations in ambient power generation are usually weak. Therefore, it is desired that a vibration generator can obtain larger electrical energy from weak vibrations. On the other hand, the applications of vibration generators are expanding. For example, it is also expected to be applied to a technique for detecting a specific frequency in vibrations generated in civil engineering structures or building structures and grasping the state (degree of deterioration) of the structures. In this case, in order to obtain an electrical signal of sufficient magnitude for analysis, it is desired to mount a vibrator that resonates at a specific vibration frequency previously grasped in the target structure to generate electricity. However, since the specific vibration frequencies are different for each structure, it is necessary to create a dedicated vibration generator for each structure, which is not easy to achieve from the viewpoints of cost and man-hours.
[0005] Furthermore, separate from understanding the condition of a structure, if a vibration generator with an oscillator that resonates at a specific frequency is installed in a location or structure where vibrations at that frequency are strong, power can be generated with high efficiency.
[0006] As is clear from these points, it is desirable that vibration generators allow for easy modification of the resonant frequency of the oscillator.
[0007] Therefore, the object of the present invention is to provide a vibration generator that can easily change the resonant frequency of the oscillator. [Means for solving the problem]
[0008] To solve the above-mentioned problems, one aspect of the present invention has the following configuration 1). 1) Frame and, A damper portion having a hole in the center, with its peripheral edge fixed to the frame and its central portion elastically movable in the axial direction, A vibration unit having a bobbin formed in a cylindrical shape around which a coil is wound and fixed to the hole in the damper part, and a weight holder fixed to close the opening on one end of the bobbin and on which a weight can be attached and detached, A magnetic circuit fixed to the frame and generating a magnetic flux linked to the coil, Equipped with, This is a vibration generator that generates electricity when the vibration unit moves in the axial direction due to external vibrations. [Effects of the Invention]
[0009] According to one aspect of the present invention, the effect is obtained that the resonant frequency of the oscillator can be easily changed. [Brief explanation of the drawing]
[0010] [Figure 1] Figure 1 is a longitudinal cross-sectional view showing the configuration of a vibration generator 91 according to one aspect of the present invention. [Figure 2] Figure 2 is a disassembled cross-sectional view illustrating a portion of the vibration unit 7 of the vibration generator 91. [Figure 3]Figure 3 is a top view of the weight holder 71 in the vibration unit 7. [Figure 4] Figure 4 is a longitudinal cross-sectional view showing a modified example of the vibration generator 91, namely vibration generator 91A. [Modes for carrying out the invention]
[0011] The vibration generator of the present invention will be described with reference to Figures 1 to 3, using vibration generator 91, which is one embodiment of the invention, as an example. Figure 1 is a longitudinal cross-sectional view showing the configuration of vibration generator 91 according to one embodiment of the present invention. Figure 2 is a disassembled cross-sectional view showing a part of the vibration unit 7 of vibration generator 91 for illustrative purposes. Figure 3 is a top view of the weight holder 71 in the vibration unit 7. The vertical direction in this description is defined by the direction of the arrow shown in Figure 1. This vertical direction is the vertical direction and corresponds to the operating orientation of vibration generator 91.
[0012] The vibration generator 91 comprises a frame 1, a damper section D, a magnetic circuit 5, and a vibration unit 7 which is an oscillator. The frame 1 is formed in a substantially circular pot shape with annular side walls 11 and a bottom wall 12 centered on an axis CL1 extending vertically. Two stepped sections 11a and 11b are formed on the side wall 11 at positions separated in the axial direction, and a circular opening 12a is formed on the bottom wall 12 that is concentric with the axis CL1.
[0013] A damper section D is attached to the stepped portion 11a on the opening side of frame 1. The damper section D has one or more dampers, and in this example, the damper section D has two dampers, a first damper 2 and a second damper 3. The first damper 2 is formed in a disc shape with a circular hole 2a in the center, and its peripheral edge is connected and fixed to the upper end of the spacer 4 which is fixed to the stepped portion 11a. The first damper 2 has a circular fold in a top view, which is undulating in the vertical direction in cross-sectional shape, and this allows the central portion near the hole 2a to move elastically in the vertical direction.
[0014] The second damper 3 is formed to have the same shape as the first damper 2 in this example. The peripheral edge of the second damper 3 is fixed to the base of the spacer 4. The central circular hole 3a of the second damper 3 and the central hole 2a of the first damper 2 are identical in shape and position when viewed from above. Spacer 4 determines and maintains the distance between the first damper 2 and the second damper 3 in the direction of the axis CL1.
[0015] As shown in Figures 1 and 2, a vibration unit 7, which serves as an oscillator, is fixed to the holes 2a and 3a of the first damper 2 and the second damper 3, respectively, by adhesive or other means. The vibration unit 7 comprises a weight holder 71, a bobbin 72, a coil 73, and a weight 74. The bobbin 72 is a cylindrical member made of polyimide resin or the like. The holes 2a of the first damper 2 and the holes 3a of the second damper 3 are adhesively fixed to the outer circumferential surface of the upper part of the bobbin 72. The bobbin 72 is supported so as to be able to move up and down by only the first damper 2 and the second damper 3. The coil 73 is wound around the outer circumferential surface of the lower part of the bobbin 72. Both ends of the coil 73 are pulled out and connected to a pair of connection terminals (not shown).
[0016] The weight holder 71 is adhesively fixed to the bobbin 72 so as to close the opening at the upper end, which is one end of the bobbin 72, and is made of a non-magnetic material. The weight holder 71 has a flange 711, a peripheral wall portion 712, and a bottom wall portion 713, and is formed in a deep pot shape that is circular when viewed from above, with the axis CL7 extending vertically in Figure 3 as the center. The peripheral wall portion 712 is formed as an inclined peripheral surface whose vertical cross-sectional shape decreases in diameter from the opening side toward the bottom wall portion 713. The flange 711 is the portion that protrudes outward from the opening edge at the upper end of the peripheral wall portion 712 all around. In the center of the bottom wall portion 713, there is a female thread portion 714 having a female thread concentric with the axis CL7.
[0017] The weight holder 71 has radial slits 712a in a top view that connect the lower part of the peripheral wall portion 712 and the edge of the bottom wall portion 713. In this example, as shown in FIG. 3, four slits 712a are formed at 90° intervals in a top view. The number and angular interval of the slits 712a to be formed are not limited. There may be one slit 712a, or it may not have the slit 712a depending on the specifications. When forming the slit 712a, it is preferably formed at positions and in a shape that is point-symmetric about the axis CL7 from the viewpoint of the vibration balance of the vibration unit 7.
[0018] As shown in FIGS. 1 and 2, a non-magnetic weight body 74 is detachably mounted and fixed inside the weight holder 71. The weight body 74 may be a single mass, or may be an assembly of a plurality of weights 741 as in this example. For the weight 741, for example, a non-magnetic washer (including washer-shaped members) can be used. A plurality of arbitrary weights 741 are stacked, and a small screw, which is a fixture 742, is inserted through the central hole of the weight 741 and screwed into the female thread of the female thread portion 714 to be fixed to the weight holder 71.
[0019] With the above configuration, the mass and number of each of the weights 741 can be easily and arbitrarily selected. That is, by selecting the mass and number of the weights 741, the mass of the vibration unit 7, which is a vibrator, can be set to an arbitrary mass. Therefore, the resonance frequency depending on the mass of the vibration unit 7 supported so as to be vertically movable only by the first damper 2 and the second damper 3 can be easily set to an arbitrary frequency. [[ID=……]]
[0020] [[ID=……]] Returning to FIG. 1, a magnetic circuit 5 is fixed to the stepped portion 11b of the frame 1. The magnetic circuit 5 is configured to include, in order from above, an auxiliary magnet 51, a top plate 52, a main magnet 53, and a yoke 54.
[0021] The sub-magnet 51, top plate 52, and main magnet 53 are formed in a ring shape with an opening in the center. The yoke 54 has a cylindrical center pole 541 that protrudes upward in the center, and its vertical cross-sectional shape is formed in an inverted T shape.
[0022] The center pole 541 enters the central opening of the main magnet 53 and top plate 52 from below, and is positioned so that its upper surface extends to a position above the top plate 52.
[0023] The gap S, which is the circumferential gap between the center pole 541 and the top plate 52, sub-magnet 51, and main magnet 53, is narrowest when it is between the top plate 52 and the center pole 541. The bobbin 72, around which the coil 73 is wound, enters this gap S from above and is maintained without contact with other components. The winding range of the bobbin 72 in the vertical direction includes at least the range facing the top plate 52.
[0024] In the magnetic circuit 5, the highest density of magnetic flux passes between the inner surface of the top plate 52 and the outer surface of the center pole 541, so a high density of magnetic flux links with the coil 73.
[0025] When the vibration generator 91 with the above configuration is fixed to a vibration source or a part through which the vibration propagates, for example, in a position where the axis CL1 is in the vertical direction, the vibration unit 7 moves vertically relative to the frame 1 and magnetic circuit 5 due to the vertical component of the external vibration. As a result, the coil 73, which moves vertically, passes over the magnetic flux of the magnetic circuit 5, generating an electromotive force, and an electrical signal with a waveform and amplitude corresponding to the vibration is obtained from the output terminal.
[0026] If the vibration from the vibration source is at a specific frequency, or if it is desired to detect a specific frequency component in the vibration, the mass and number of weights 741 are selected and fixed with the fixing device 742 so that the vibration unit 7 resonates at that specific frequency. In other words, the resonant frequency can be adjusted by changing the mass of the weight body 74. If mass adjustment beyond the mass adjustment range of the weights 741 is required, this can be addressed by increasing or decreasing the overall mass of the vibration unit 7, for example.
[0027] As a result of testing the vibration generator 91 described above by prototyping it and applying vibration to generate electricity, it was confirmed that the resonant frequency of the vibration generator 91 can be changed as shown in (Table 1) below by changing the number of weights 741, that is, by changing the mass of the weights 74.
[0028] [Table 1] This is the result obtained with the prototype vibration generator 91, and the resonant frequency value and adjustment range can be set to different values depending on the specifications of the vibration generator (magnetic characteristics of the magnetic circuit 5, shape and mass of the vibration unit 7, damping characteristics of the damper section D, etc.).
[0029] Thus, the vibration generator 91, which generates electricity from vibration, allows for the modification of its resonant frequency, and this modification is very simple as it can be done by selecting at least one of the mass and number of weights 741. For example, consider a case where the object of measurement is a bridge, and the natural frequency mainly generated by the passage of vehicles on the bridge is identified as 30 Hz, and power is generated using a vibration generator 91 having the characteristics shown in Table 1. In this case, by attaching two weights 741, each weighing 20 g, to the weight holder 71, the resonant frequency of the vibration generator 91 can be roughly matched to the natural frequency of the bridge. This allows for a large amplitude of vibration unit 7, enabling efficient power generation from the vibration of the bridge.
[0030] The embodiments of the present invention are not limited to the configurations described above, and may be modified without departing from the spirit of the invention.
[0031] (Variation 1) As shown in Figure 1, the space V1 between the center pole 541, bobbin 72, and weight holder 71 is substantially sealed space if there are no other gaps, because the gap S is very small. Therefore, if you do not want to affect the vertical movement of the vibration unit 7, you can eliminate the air resistance in space V1 by providing a slit 712a in the weight holder 71 in a manner that is not blocked by the weight 741, as an air passage between space V1 and the outside space, as in one embodiment described above. Conversely, if you want the air resistance in space V1 to function as a damper to brake the vertical movement of the vibration unit 7, you do not need to form the slit 712a.
[0032] Furthermore, if the specifications of the vibration generator 91 prevent a large vertical distance between the center pole 541 and the weight holder 71, there is a risk that the weight holder 71 may directly collide with the upper surface of the center pole 541 due to the large vertical movement of the vibration unit 7 caused by resonance. To prevent this direct collision, a buffer member 8 such as a coil spring can be placed on the upper surface of the center pole 541, as shown in Figure 4. The buffer member 8 is not limited to a coil spring; it may also be a foamed material such as sponge.
[0033] As shown in Figure 1, the vertical position of the center of gravity G of the weight holder 71 to which the weight 74 is fixed changes in the direction of the axis CL1 (vertical direction) depending on the number of weights 741. When the damper section D has two dampers, the first damper 2 and the second damper 3, it is preferable that the range between the position of the center of gravity G when there are no weights 741 in the weight holder 71 and the position of the center of gravity G when the maximum number of weights that can be accommodated is fixed be included between the height position H1 of the first damper 2 and the height position H2 of the second damper 3. As a result, the vertical position of the center of gravity G of the weight holder 71 is determined between the first damper 2 and the second damper 3, regardless of the number of weights 741. This allows the vibration unit 7 to be supported more stably by the first damper 2 and the second damper 3, and the vibration unit 7 moves up and down stably without axial wobble.
[0034] Either one or both of the first damper 2 and the second damper 3 do not have to be disc-shaped and can be of any shape. If the damper section D has one damper, the vertical center of gravity of the weight holder 71 in the direction of the axis CL1 should be set to be within the range centered on the connection point of one damper.
[0035] One embodiment of the vibration generator 91 has a structure similar to that of an electroacoustic converter that converts electrical signals into sound. Therefore, it can be manufactured using the manufacturing processes, manufacturing technologies, and quality control methods of an electroacoustic converter, offering many manufacturing advantages, such as the ability to maintain high quality well. [Explanation of Symbols]
[0036] 1 frame 11 Side wall 11a,11b Stepped section 12 Bottom wall 12a opening 2. First Damper 2a hole 3. Second Damper 3a hole 4 Spacers 5 Magnetic Circuit 51 Sub-magnet 52 Top Plate 53 Main Magnet 54 York 541 Center Pole 7. Vibration Unit 71 Weight holder 711 Flange 712 Peripheral wall section 712a Slit 713 Bottom wall section 714 Female thread section 72 bobbins 73 coils 74 Pyramid 741 Weight 742 Fixtures 8. Cushioning material 91 Vibration Generator CL1,CL7 axis line D Damper section H1, H2 Height position G center of gravity S Gap V1 space
Claims
1. Frame and, A damper portion having a hole in the center, with its peripheral edge fixed to the frame and its central portion elastically movable in the axial direction, A vibration unit having a bobbin formed in a cylindrical shape around which a coil is wound and fixed to the hole in the damper part, and a weight holder fixed to close the opening on one end of the bobbin and on which a weight can be attached and detached, A magnetic circuit fixed to the frame and generating a magnetic flux linked to the coil, Equipped with, A vibration generator that generates electricity when the vibration unit moves in the axial direction due to external vibrations.
2. The vibration generator according to claim 1, wherein the resonant frequency of the vibration unit can be adjusted by changing the mass of the weight attached to the weight holder.
3. The vibration generator according to claim 2, wherein the damper section comprises a first damper and a second damper spaced apart in the axial direction.
4. The vibration generator according to claim 3, wherein the position of the center of gravity of the weight is between the first damper and the second damper in the axial direction.
5. The vibration generator according to claim 4, wherein the weight body is a single flat washer-shaped weight or a plurality of stacked weights.
6. The vibration generator according to claim 1, further comprising a buffer member for preventing direct collision between the vibration unit moving in the axial direction and the magnetic circuit.