Vibration-proof material

Abstract

To provide a vibration control material capable of absorbing vibration of low frequency and suppressed in horizontal variation.SOLUTION: A vibration control material is manufactured. The vibration control material includes: an outer peripheral cylinder 12 having a column or regular polygonal column-like shape; a bottom plate 13 disposed at a lower portion of the outer peripheral cylinder 12; a vibration absorption portion 16 having one or more connection cylinders 14 disposed at an upper side of the inside of the outer peripheral cylinder 12, having a column or regular polygonal column-shape, and disposed coaxially with the outer peripheral cylinder 12, and an elastomer-filled portion 15 composed of an elastomer closing between the cylinders; a fixing tool 17 disposed at an upper side of the center of the vibration absorption portion 16; and an elastic body 18 disposed inside of the outer peripheral cylinder 12, and energizing the bottom plate 13 and the vibration absorption portion 16 in a direction separating from each other.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a vibration-isolating material that absorbs vibrations. [Background technology]

[0002] Various vibration-proofing materials that absorb and support vibrations have been proposed depending on the frequency of the vibration, the load they support, etc. For example, as shown in Figure 9(a), a vibration-proofing material 1 is used in which a buffer part 2 made of a material with rubber elasticity is sandwiched between the top and bottom, and this material absorbs the vibrations of the upper part.

[0003] As a similar technology, for example, Patent Document 1 describes a vibration-proof structure that uses two layers of rubber to receive vibration and prevent the vibration from reaching the piping. One application is to support the compressor in a refrigeration cycle device, and to provide vibration protection while supporting a large load. A vibration-proof structure has also been proposed in which even more layers are added than in this example, with many layers stacked on top of each other.

[0004] However, with this type of vibration-proofing material, when a load is applied in the shear direction and a force is applied in the compression direction, the rubber hardness of the rubber that absorbs the vibration increases. When the rubber hardness increases, the natural frequency increases, and the lower limit of the vibration frequency that can be absorbed increases. For example, if it is attached to a drone, it may be able to absorb high-frequency vibrations of several tens of Hz or more caused by the rotation of the wings, but it cannot absorb low-frequency vibrations of 5 Hz or less caused by the movement of the drone itself. In particular, with a vibration-proofing structure made up of many stacked layers, horizontal vibrations are easily absorbed due to the misalignment between the layers, but on the other hand it becomes difficult to deform when subjected to loads in the vertical direction (compression direction), and the rubber hardness increases.

[0005] If the rubber that constitutes the vibration-proofing material is to be able to absorb low-frequency vibrations even when compressive forces are applied in the vertical direction, the original hardness of the rubber must be lowered. However, even if rubber with a hardness as low as 0 is used, the lower limit of the vibration frequency that it can absorb is only about 10 Hz. If the rubber used for the buffer part 2 is this soft, it may be able to absorb vibrations, but it is too soft and easily deforms with left-right movement, as shown in Figure 9(b), and it will no longer be able to support anything above it.

[0006] If a hollow air damper is used, with the upper part supported by a leaf spring or the like instead of rubber, vibrations up to about 5 Hz can be absorbed. Patent Document 2 proposes a shock absorber that has a hollow part and is supported on the periphery by rubber or a coil spring.

[0007] As another configuration, Patent Document 3 proposes a vibration-proof structure that supports vertical vibrations by tension rather than compression stress. The load applied from above is absorbed by being pulled between the fixed outer periphery and the vertically moving center portion, rather than by pressing down on the insulator rubber (7). Therefore, even when a load is applied, the rubber hardness of the insulator rubber does not increase, and the characteristic feature is that the natural frequency can be maintained low. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 11-2439 [Patent Document 2] Japanese Unexamined Patent Publication No. 63-72938 [Patent Document 3] Japanese Utility Model Application Publication No. 63-43887 Summary of the Invention [Problem to be solved by the invention]

[0009] However, in the case of hollow vibration-proofing members as shown in Patent Document 2, the rubber hardness is unlikely to increase even when a load is applied, and it is thought that the vibration-proofing performance in the vertical direction can maintain a low natural frequency, but since there is no support in the horizontal direction, it becomes difficult to fix it, and the whole moves, and it takes too long for the movement to settle. For example, in a factory line, there is a problem that the relative position between the front and rear moves too much and the position becomes misaligned.

[0010] Furthermore, in the vibration-proofing material described in Patent Document 3, vibrations are absorbed only by the insulator rubber, which is pulled. Therefore, although an increase in the natural frequency can be avoided, absorption of horizontal vibrations is insufficient, and there are problems with regard to load resistance.

[0011] Therefore, an object of the present invention is to realize a vibration-damping material whose natural frequency is unlikely to increase even in a load-bearing environment, which maintains a low natural frequency and is capable of damping low-frequency vibrations, and which can also demonstrate support performance against horizontal movements. [Means for solving the problem]

[0012] The present invention relates to An outer cylinder having a cylindrical or regular polygonal prism shape; A bottom plate provided at one end of the outer tube; a vibration absorbing section including one or more cylindrical or regular polygonal prism-shaped connecting tubes arranged coaxially with the outer tube and an elastomer filling section made of an elastomer filling the space between the tubes, the vibration absorbing section being located inside the other end of the outer tube; A fixture provided on the other end side of the center of the vibration absorbing part; an elastic body provided inside the outer tube for biasing the bottom plate and the vibration absorbing portion in a direction away from each other; The above problem was solved by using a vibration-proof material having the above structure.

[0013] Here, the space between the cylinders includes not only the space between the outer cylinder and the connecting cylinder, but also the spaces between the connecting cylinders when there are a plurality of connecting cylinders. Also, when the connecting cylinder located at the innermost circumference is a central cylinder or central pillar integrated with the fixing device, it also includes the space between the central cylinder or central pillar and the connecting cylinder.

[0014] This vibration-proofing material is generally installed with the bottom plate facing downwards. Loads and vibrations are applied from above through the fixing device. The elastomer-filled portion of the vibration-absorbing section is pulled between the cylinders to absorb these loads and vibrations. Because the load is applied in the tensile direction and not in the compressive direction, the hardness of the rubber that constitutes the elastomer-filled portion does not increase excessively, and an increase in the natural frequency can be suppressed. In addition, the applied load is supported not only by the force of the elastomer-filled portion trying to return to its original position, but also by the biasing force of the elastic body, preventing the elastomer-filled portion from being subjected to excessive force, causing it to deteriorate or break.

[0015] The connecting tube, which is arranged coaxially with the outer tube, disperses and absorbs the vibration and load applied to the elastomer-filled portion without bias. This makes it difficult for distortion to occur in the horizontal direction, and not only can it absorb vibration, but it also maintains high shape stability.

[0016] The elastic body may be either a leaf spring or a coil spring. When using the coil spring, the coil spring may be arranged so as to be positioned on the central axis of the outer cylinder, and an embodiment may be adopted in which a recessed dish portion for receiving and fixing the coil spring is provided on the other end side of the center of the bottom plate. In addition, it is preferable that the vibration absorbing portion side of the coil spring is accommodated inside the central cylinder integrated with the fixing device, since the coil spring can be fixed without being displaced in the horizontal direction.

[0017] Furthermore, if there are multiple elastomer-filled sections between the cylinders and the number of divisions increases, the amount of deformation for each elastomer-filled section can be reduced, and the vertical spring constant can be reduced. This reduces the natural frequency and lowers the lower limit of the frequency of vibration that can be absorbed. It also reduces horizontal deviations, making it easier to maintain the horizontal position. Effect of the Invention

[0018] By using the vibration-proofing material of this invention, it is possible to avoid an increase in rubber hardness due to load, and therefore it is possible to absorb lower frequency vibrations than conventional vibration-proofing materials that are laminated with elastomers. It is possible to absorb vibrations in the frequency range from 1.4 times the natural frequency and above, and depending on the combination of the coil spring and the elastomer-filled portion, it is possible to absorb vibrations up to a low frequency of about 1.4 to 7 Hz. It is also possible to absorb low frequency vibrations not only in the vertical direction but also in the horizontal direction.

[0019] As a result, when mounted on a drone, for example, it can absorb not only high-frequency vibrations caused by propeller rotation, but also low-frequency vibrations caused by the large movements of the drone itself, and by fixing a camera via the vibration-isolating material of this invention, blurring of drone footage can be significantly suppressed. Also, while a sufficient load had to be applied to lower the natural frequency, the vibration-isolating material of this invention has a sufficiently small natural frequency even in an environment with a light load such as a drone, and can absorb even low-frequency vibrations.

[0020] Even if the product is installed in a situation where the load-bearing capacity continues for a long period of time, the elastic body and the vibration-absorbing part can absorb the load together, so the material hardly deteriorates and the product has a long service life. This makes the product ideal as a vibration-proof material for heavy objects or buildings that cannot be replaced for a long period of time. Since the product can absorb low-frequency vibrations, it can also absorb earthquake vibrations to a certain extent. [Brief description of the drawings]

[0021] [Figure 1]FIG. 1A is a perspective view of a vibration-proof material according to a first embodiment of the present invention; FIG. [Diagram 2] (a) Cross-sectional view along II-II in FIG. 1(a), (b) Plan view of FIG. 1(a) [Diagram 3] FIG. 1A is a perspective view of a vibration-proof material according to a second embodiment of the present invention; FIG. [Figure 4] 3 is a cross-sectional view of a vibration-proof material according to a third embodiment of the present invention. [Diagram 5] A schematic diagram of a drone equipped with the vibration-proofing material of this invention. [Figure 6] Graph showing the relationship between load and displacement in Examples 1 and 2 [Figure 7] Photographs showing the measurement of the natural frequency in Example 1 and a display showing the measurement results [Figure 8] Photographs showing the measurement of the natural frequency in Example 2 and a display showing the measurement results [Figure 9] (a) A diagram showing an example of a conventional vibration-proof material, (b) A conceptual diagram of what happens when (a) can no longer maintain its shape. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is directed to a vibration-proof material 11 capable of absorbing vibrations when subjected to vibrations and loads.

[0023] The first embodiment of the vibration-proof material 1 according to the present invention will be described as an example. A perspective view of the first embodiment is shown in Fig. 1. The vibration-proof material 11 according to the first embodiment has an appearance as shown in the perspective view of Fig. 1(a) and the front view of Fig. 1(b). A cross-sectional view along II-II is shown in Fig. 2(a), and a plan view seen from above is shown in Fig. 2(b).

[0024] The vibration-proof material 11 according to the present invention has an outer tube 12 that is cylindrical or regular polygonal prism-shaped. In Figs. 1 and 2, an embodiment having a cylindrical outer tube 12 is shown as an example. In the case of a regular polygonal prism, it is preferable that the outer tube 12 is a regular pentagonal prism or more, and more preferable that the outer tube 12 is a regular hexagonal prism or more. If the outer tube 12 is a regular square prism or less, the corners are small and the load and vibration are likely to be biased, which may lead to insufficient vibration absorption effect or unexpected movement. When trying to align the position with the fixing hole 22 described later, a regular octagonal prism or other square shape that is a power of two is preferable because it is easy to arrange in terms of design. On the other hand, the more polygonal the shape, the less the load is biased, and a cylindrical shape is most preferable in terms of durability and vibration-proof effect.

[0025] The material of the outer cylinder 12 can be appropriately selected depending on the application and size. If it is a resin, it is preferable to use a resin such as polycarbonate or ABS resin, which is used for applications requiring relatively high strength and weather resistance, rather than a relatively brittle resin such as acrylic resin. In addition, it may be a casting of stainless steel, aluminum, or other metals, or may be formed by machining.

[0026] The thickness T1 of the outer tube 12 is preferably 2% or more of the maximum diameter of the outer tube 12, and more preferably 4% or more when strength is required. In particular, when the vibration-proof material 11 is large, such as having a maximum diameter exceeding 1 meter, if a certain thickness is not secured for the maximum diameter, it may not be able to withstand the load applied. Even if the maximum diameter is small, such as 1 cm or less, a thickness is required to ensure strength when the load is concentrated. Although it depends on the material, if it is less than 2% of the maximum diameter, it is difficult to ensure sufficient durability, and there is a risk that it may be distorted, the vibration-proof effect may be reduced, or it may not be able to withstand the load and break. In addition, the maximum diameter of the outer tube 12 here is the outer diameter of a circle when it is cylindrical, and is the length of the diagonal of a regular polygon that is the maximum length when it is polygonal. On the other hand, a thicker thickness is preferable from the standpoint of durability, but if it exceeds 15% of the outer diameter of the outer tube 12, it becomes difficult to secure sufficient space to install the connecting tube 14 and elastomer filling section 15 described below, so it is preferable for the thickness to be 15% or less of the outer diameter of the outer tube 12.

[0027] The vibration-proof material 11 according to the present invention has a bottom plate 13 provided at one end of the outer tube 12. Basically, the vibration-proof material 11 is installed with this bottom plate 13 facing down. Hereinafter, when referring to up and down, the bottom plate 13 side is referred to as facing down. The bottom plate 13 may be integrated with the outer tube 12, or may be removable. However, if it is removable, it is preferable to have a separate mechanism for fixing it so that it is not easily removed by the force applied by the elastic body 18 described below. The example shown in Figures 1 and 2 is an embodiment in which the outer tube 12 and the bottom plate 13 are integrated.

[0028] The bottom plate 13 may be fixed to other equipment or the floor surface provided below. Specifically, it is preferable that the bottom plate 13 has a fixed wing portion 21 protruding beyond the outermost periphery of the outer tube 12, or is integrated with a plate for other purposes. An example of a plate for other purposes is the top plate of an object to which the vibration-proof material 11 is to be attached, and the top plate may be shaped to serve as the bottom plate 13 in this invention. In the example shown in Figures 1 and 2, the fixed wing portions 21, 21 protrude to the left and right so as to be point symmetrical with respect to the central axis of the outer tube 12. Each of the fixed wing portions 21 has a fixing hole 22 for enabling screwing to an equipment provided below.

[0029] The vibration-proofing material 11 according to the present invention has a vibration-absorbing section 16 inside the other end side of the outer tube 12, which has one or more connecting tubes 14 that are cylindrical or regular polygonal prism-shaped and arranged coaxially with the outer tube 12, and an elastomer-filled section 15 made of elastomer that fills the space between the tubes. If any two or more of the outer tube 12 and the connecting tubes 14 are regular polygonal prism-shaped, it is desirable that the number of corners of the polygonal prisms is the same. For example, if regular hexagonal prisms and regular octagonal prisms are mixed, there is a risk that the vibration absorption will be biased, or that the connecting tubes 14 will come into contact with each other depending on the angle, greatly reducing the vibration-proofing effect. At least the individual connecting tubes 14 are arranged so as not to contact each other or the outer tube 12, and elastomer-filled sections 15 (15a, 15b, 15c, etc.) are provided between the tubes.

[0030] In the embodiment shown in Figs. 1 and 2, the connecting tube 14 includes connecting tubes 14a and 14b from the outside, and a connecting tube (central tube) 14x integrated with a fixing device 17 described later. These connecting tubes 14 are arranged coaxially with the outer peripheral tube 12, meaning that they are arranged so that the central axis A of the cylinder or regular polygonal prism of the outer peripheral tube 12 coincides with the central axis of each connecting tube 14. When both the outer peripheral tube 12 and the connecting tube 14 are cylindrical, as shown in Fig. 2(b), their shapes when viewed from above in a plan view are concentric. On the other hand, when any two or more of the outer peripheral tube 12 and the connecting tube 14 are regular polygonal prisms, it is desirable that they are polygonal prisms with the same number of corners.

[0031] As an example, a second embodiment in which the outer tube 32 and the connecting tube 34 are both regular octagonal prisms is shown in Fig. 3. Fig. 3(a) is a perspective view, and Fig. 3(b) is a plan view. In accordance with the shape of the tubes, the elastomer filling section 35 is also not annular, but has an outer periphery in the shape of a regular octagonal prism. By aligning the corners of the outer tube 32 and the connecting tube 34, they can absorb vibrations stably without being biased regardless of the direction from which force is applied.

[0032] The material of the connecting tube 14 is not particularly limited. It may be made of resin or metal. However, it is preferable that the connecting tube 14 is made of a material that does not deteriorate due to contact with the elastomer-filled portion 15. It is more preferable that the connecting tube 14 is made of a material that can firmly adhere to the elastomer-filled portion 15.

[0033] The thickness (T2, T3, ...) of the connecting tube 14 is preferably 0.2% or more of the maximum diameter of the outer tube 12. In particular, when the vibration-proof material 11 is large, such as having a maximum diameter exceeding 1 meter, if a certain thickness is not secured for the maximum diameter, it may not be able to withstand the load applied. Here, the maximum diameter of the connecting tube 14 is the outer diameter of the circle when it is cylindrical, and the length of the diagonal of the regular polygon that is the maximum length when it is polygonal prism. On the other hand, although a thicker thickness is preferable from the viewpoint of durability, if it exceeds 15% of the outer diameter of the outer tube 12, it becomes difficult to secure a sufficient space for providing the elastomer filling portion 15, so it is preferable that the thickness is 15% or less of the outer diameter of the outer tube 12. As long as the durability in the usage environment can be secured, it is basically preferable to reduce the thickness of the connecting tube 14 and increase the number of connecting tubes 14 accordingly to lower the natural frequency, thereby lowering the lower limit of the vibration frequency that can be absorbed. For example, when the maximum diameter is small, on the order of centimeters, a resin film having a thickness of about 10 to 100 μm can be used as connecting tube 14. Even with a thin connecting tube 14, the effect of lowering the natural frequency can be achieved by repeating the structure in which the bonded portion between the connecting tube 14 and elastomer-filled portion 15 is pulled up and down multiple times.

[0034] The vertical length of the connecting tube 14 must be smaller than the vertical length of the outer peripheral tube 12. The vertical length of the connecting tube 14 is preferably 90% or less of the vertical length of the outer peripheral tube 12. If it exceeds 90%, there is a risk that the connecting tube 14 may even come into contact with the bottom plate 13 when a load is applied from above. On the other hand, the vertical length of the connecting tube 14 is preferably 20% or more of the vertical length of the outer peripheral tube 12. If it is less than 20%, the amount of elastomer filling portion 15 connecting the tubes will be small, and the effect of absorbing shock and vibration will be insufficient.

[0035] The elastomer filling section 15 fills the space between the cylinders with an elastomer. Examples of the elastomer used here include urethane elastomer, ethylene elastomer, and silicone elastomer. Natural rubber is not preferable because it has too high rubber elasticity. The elastomer filling section 15 is pulled by the inner and outer cylinders, and acts as a vibration-proof material that can absorb low-frequency vibrations by trying to return to its original state from the pulled state. The vibration is converged by the elastomer filling section 15.

[0036] As for the structure for bonding the elastomer-filled portion 15 to the outer peripheral tube 12 or the connecting tube 14, the elastomer may be bonded to the outer peripheral tube 12 or the connecting tube 14 with an adhesive, or the elastomer itself may be firmly bonded to the outer peripheral tube 12 or the connecting tube 14. These are put together to form the vibration-absorbing portion 16.

[0037] The radial thicknesses W1, W2, W3, . . . of the elastomer-filled portions 15 (15a, 15b, 15c, . . . ) are the same as the thickness T x If the thickness is thinner than the connecting tube 14, the allowable range of deformation in the vertical direction is too small, making it difficult to obtain a sufficient vibration-proofing effect. x is preferably 2% or more of the maximum diameter of the outer tube 12, and more preferably 4% or more. Although it depends on the maximum diameter of the outer tube 12, if it is less than 2%, the allowable range of the deviation of the vertical pull is too small compared to the deviation range required by the size of the outer tube 12, and the vibration-proofing effect is likely to be insufficient. On the other hand, there is no particular limit to the thickness, but the thickness of one elastomer-filled portion 15 is preferably 25% or less of the maximum diameter of the outer tube 12, and more preferably 15% or less to ensure multiple layers of the elastomer-filled portion 15. If only one elastomer-filled portion 15 is too thick, the effect of multi-stage shock absorption by the connecting tube 14 provided in the middle may be biased or insufficient. The individual thicknesses W1, W2, and W3 may be the same or different.

[0038] The procedure for forming such a vibration absorbing part 16 can be, for example, a procedure in which a frame for arranging the connecting tube 14 so that the axes are aligned inside the outer tube 12 is assembled, and a resin that becomes a hardening elastomer, such as liquid urethane, is poured into the frame and the whole is hardened. Although the method for hardening the frame requires precision in the work, the elastomer filling part 15 that fills the space between the tubes is firmly bonded to the outer tube 12 and the connecting tube 14, and can exhibit high durability. Another procedure can be a procedure in which a resin that becomes a hardening elastomer is poured into a frame in which the connecting tube 14 is arranged separately from the outer tube 12, and hardened, and then the periphery of the elastomer filling part 15a is machined, attached to the inner circumference of the outer tube 12, and fixed with an adhesive.

[0039] The vibration-proof material 11 according to the present invention has a fixture 17 at the other end side (i.e., the upper side) of the center of the vibration-absorbing part 16. The fixture 17 is a part that can fix another member located above the vibration-proof material 11 to the vibration-proof material 11. In the embodiment shown in Figs. 1 and 2, it is integrated with a central tube 14x having a female thread. Conversely, a form in which a male thread protrudes upward may be used. In the case of a form in which a male thread protrudes upward, the lower part of the fixture 17 may be a central pillar that has no cavity inside or has a cavity that is closed halfway, instead of the central tube 14x. Even in such a case where it is not strictly cylindrical, the periphery of the central pillar is filled with an elastomer filling part 15, which is similarly described as the space between the cylinders above.

[0040] The side surface of the fixture 17 may have at least one, preferably two or more, rotation fixing holes 24. Whether the fixture 17 is male or female threaded, when the fixture 17 is to be attached to another member disposed above, a force acts to rotate the fixture 17 in a twisting direction. If the fixture 17 is left as it is, a force is applied to the inner connecting tube 14 in the twisting direction, which pulls the elastomer-filled portion 15 and causes it to be fixed in a continuously twisted state or to be screwed off. For this reason, when applying a rotation force to attach another member to the male or female thread of the fixture 17, a rod-shaped member for fixing is inserted from the side into the rotation fixing hole 24, and the fixture 17 and the central tube 14x are fixed so that they do not rotate in the twisting direction. The inner circumference of the rotation fixing hole 24 is preferably cut into a square or hexagonal shape to prevent slipping. In the embodiment shown in the figure, the hole is cut into a hexagonal shape.

[0041] The vibration-proof material 11 according to the present invention has an elastic body 18 provided inside the outer tube 12, which urges the bottom plate 13 and the vibration absorbing part 16 in a direction away from each other. In other words, it is provided in the space below the vibration absorbing part 16 and above the bottom plate 13. The elastic body 18 may be any material that can urge in the vertical direction, such as a leaf spring or a coil spring. In the embodiment shown in Figs. 1 and 2, a coil spring is used.

[0042] When the elastic body 18 is a coil spring, a concave plate portion 20 is preferably formed in the upper center portion of the bottom plate 13 to hold the coil spring and fix it so that it does not move in the horizontal direction, so that the coil spring does not come off. Specifically, it is preferable that the concave portion has a diameter slightly larger than the diameter of the coil spring. The depth of the concave portion is preferably equal to or greater than the thickness of one wire forming the coil spring, and more preferably equal to or greater than the thickness of two wires. If the concave portion is too shallow, the coil spring may slip out of place even if there is a concave portion. On the other hand, it is preferable that the upper end side of the coil spring is accommodated in the lower portion of the central tube 14x, since there is almost no possibility of the coil spring slipping out of place in the horizontal direction. However, it is preferable that a reduced diameter portion 25 is provided in the middle of the central tube 14x to hold down the upper end of the coil spring. The radial width of the reduced diameter portion 25 is preferably equal to or greater than the thickness of one wire forming the coil spring.

[0043] When the elastic body 18 is a coil spring, it is necessary to attach it so that it can be further contracted from the length at the time of attachment. If the coil spring is compressed to the extent that the wires of the spring come into contact with each other, it cannot fully absorb the vibration in the vertical direction. On the other hand, it is preferable to attach it so that the length at the time of attachment is not the original length when no load is applied, but is in a compressed state in which the length as a spring is shortened by 5 to 50%, and more preferably is in a compressed state in which the length is shortened by 20 to 50%. This causes a force to act in a direction in which the bottom plate 13 and the vibration absorbing part 16 are separated from each other. If the spring is introduced in an unloaded state rather than in a compressed state, it is likely to show a tendency for the spring constant to increase due to displacement by the load from above. However, if the spring is introduced in a compressed state, the spring constant of the entire vibration-proof material increases more slowly, and the natural frequency is easily brought closer to zero.

[0044] The contents will be explained using specific values. For example, consider the case of attaching a coil spring that has been shortened to a length of 10 mm. Coil spring A has an original length of 15 mm and a relatively small spring constant of 0.1 kgf / mm, and coil spring B has an original length of 11 mm and a relatively large spring constant of 0.5 kgf / mm. The load required to shorten both of these to 10 mm is the same for both, 0.5 kgf. Therefore, if they are shortened to 10 mm and attached, both will support a load of 0.5 kgf. Suppose that a vibration displacement is added to this balanced state, shortening them by another 1 mm, that is, to a length of 9 mm. At this time, the repulsive elasticity, which is the force that tries to return to the original shape, is 0.1 kgf / mm x 1 mm for coil spring A, so it only requires 0.1 kgf. On the other hand, for coil spring B, it is 0.5 kgf / mm x 1 mm, so it is 0.5 kgf. In other words, coil spring B receives a stronger repulsion. The vibration-proofing material of the present invention is preferable because the weaker the force of returning to its original shape, the less vibration is transmitted, and so the coil spring A with its small resilience is preferable. Therefore, by adopting a coil spring with a small spring constant and shortening a coil spring with a long original length to a certain extent before introducing it, vibration is less likely to be transmitted, making it a preferable vibration-proofing material.

[0045] In the embodiment shown in Figures 1 and 2, an upward force is applied to the central tube 14x by the elastic body 18, which is a coil spring, and the elastomer-filled portion 15c is pulled upward by the central tube 14x, causing the upper surface to be inclined. The elastomer-filled portion 15b is pulled upward by the connecting tube 14b, which is pulled by this, causing the upper surface to be inclined. Furthermore, the elastomer-filled portion 15a is pulled by the connecting tube 14a, which is pulled by this, causing the upper surface to be inclined. In other words, the fixing device 17, which is pushed by the central tube 14x, is pushed upward.

[0046] The coil spring, which is the elastic body 18, preferably has a smaller spring constant in terms of lowering the natural frequency. On the other hand, it is required that the spring constant be capable of supporting the load to be supported depending on the application.

[0047] It is preferable that the coil spring has a margin that allows it to be compressed even further, by 5% or more of its original length, when another member is attached to the fixture 17 and a load is applied from above. If the coil spring is completely compressed when further load is applied from that state, the vibration absorbing effect will not be fully exerted.

[0048] The vibration-proof material according to the present invention may have multiple stages of vibration absorbing parts 16 inside the outer tube 12, as in the third embodiment shown in a cross-sectional view in Fig. 4. In this case, the coil springs which are the elastic bodies 38 in the second stage and onwards counting from the bottom can be shaped so that their lower parts are fixed to a recessed dish part 39 provided on the upper surface of the fixture 37. By having multiple stages of vibration absorbing parts 16, the vibration-proofing effect, particularly against vibrations in the vertical direction, may be exhibited more effectively than a single vibration absorbing part 16 which is long in the vertical direction.

[0049] The vibration-proof material of the present invention can be used, for example, in a quadcopter-type drone 51 as shown in Figure 5, by setting four vibration-proof materials at the vertices of a square in the center and fixing a camera 52 on top of them. EXAMPLES

[0050] Example 1 The present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. First, the materials used will be described. Elastomer 1: Hirakata Giken Co., Ltd.: Non-blend (rubber hardness after curing: 6) Elastomer 2: Hirakata Giken Co., Ltd.: Non-blend (rubber hardness after curing: 2) Connecting tube: Aluminum alloy, machined Outer tube: Polycarbonate

[0051] The thickness T1 of the outer cylinder and the thicknesses T2 and T3 of the connecting cylinders were 1 mm, the diameter of the outer cylinder was 30 mm, the diameter of the first connecting cylinder was 23 mm, the diameter of the second connecting cylinder was 16 mm, and the thickness of the elastomer filling part was 2.5 mm. The connecting cylinder and the outer cylinder were arranged so that a fixing tool with a female screw integrated with the central cylinder was placed in the center. The height of the connecting cylinder was 8 mm, and the height of the outer cylinder was 16 mm. However, the orientation was upside down from that in Figure 1, and a lid was temporarily placed around the fixing tool to make it the bottom. The elastomer 1 before curing was poured into the outer cylinder, poured until it filled the height of the connecting cylinder, and cured. After curing, the lid was removed, the top and bottom were returned, and the outer cylinder and the outermost elastomer filling part were cut, and the vibration absorbing part was temporarily removed from the outer cylinder. Next, the bottom end of a coil spring with a wire diameter of 0.5 mm, a spring length of 10 mm, and a spring constant of 0.2 kgf / mm was placed on the concave plate, and the top end of the coil spring was set so that it fitted into the central tube in the center of the vibration absorption section, and the outer tube and the elastomer-filled section were fixed with adhesive. At this time, a coil spring with a spring length of 10 mm was introduced as it was, completing the vibration-proof material with the shape shown in Figure 1.

[0052] Four of these vibration-proof materials were placed in a position to support the four corners of the plate to which the load was applied, and the plate and vibration-proof materials were fixed with screws. A load was applied from above the plate, and the load (N) at which the amount of displacement was indicated was measured. The load at each amount of displacement is shown in Table 1 and the graph in Figure 6. It was confirmed that the amount of displacement increases proportionally even when the load is increased. Also, with conventional vibration-proof materials made of laminated gel, the spring constant increases as the amount of displacement increases, but it was confirmed that with the vibration-proof material of this invention, the increase in the spring constant is suppressed by the action of the elastomer-filled portion.

[0053] [Table 1]

[0054] Next, a weight was placed on the plate and a vibration analyzer (Rion Co., Ltd.: VA-12) was attached from above to measure the natural frequency. A photograph showing the measurement environment is shown in the upper part of Fig. 7, while photographs showing the measurement results are shown in the lower part of Fig. 7 and in Table 2. In the graph in the lower part of Fig. 7, the horizontal axis is frequency and the vertical axis is decibels, with the frequency that shows the peak corresponding to the natural frequency. Even when the load increased and the spring was compressed, the natural frequency did not increase but decreased, demonstrating the ability to demonstrate vibration isolation performance that can absorb vibrations up to nearly 10 Hz. Furthermore, no horizontal deviation was observed even when vibrated, confirming that the structure maintained a stable posture.

[0055] [Table 2]

[0056] Example 2 In Example 1, elastomer 1 was changed to elastomer 2, the coil spring was changed to one with a spring length of 15 mm and a spring constant of 0.03 kgf / mm, and this was compressed to a spring length of 10 mm before being introduced. A vibration-proof material having the same configuration as Example 1 was manufactured. Similarly, the results of measuring the load when indicating the amount of displacement are shown in the graph of FIG. 6 and Table 3. The amount of displacement was significantly smaller than that of Example 1, even with the same amount of displacement. This shows that even when a light object with a smaller load than that of Example 1 is placed on it, sufficient displacement is shown and vibration can be absorbed. This is thought to be the effect of using a coil spring with a small spring constant and introducing the spring after shrinking it from its original size to increase the amount of displacement.

[0057] [Table 3]

[0058] Next, the natural frequency was measured in the same manner as in Example 1. The results are shown in Figure 8 and Table 4. In both the upper and lower photographs in Figure 8, the upper photograph shows the measurement environment as in Figure 7, and the lower photograph shows a graph with the horizontal axis being frequency and the vertical axis being decibels. The natural frequency is further reduced compared to Example 1, and it was shown that even with a light load, vibrations of low frequencies can be sufficiently absorbed. Note that, based on the tendency of Example 1, the natural frequency should be smaller at a load of 16.2 N, but the natural frequency is shifted because the peak is somewhat flattened.

[0059] [Table 4] [Explanation of symbols]

[0060] 1 Vibration isolation material 2 Buffer section 11 Vibration isolation material 12, 32 outer cylinder 13 Bottom plate 14,14a,14b,34 Connection tube 14x central tube 15, 15a, 15b, 15c, 35 Elastomer filling section 16 Vibration absorber 17, 37 Fixtures 18, 38 Elastic body 20, 39 Concave plate 21 Fixed wing section 22 Fixing hole 24 Rotational Fixing Holes 25 Reduced diameter part 51 Drone 52 Camera A center axis

Claims

1. An outer cylinder having a cylindrical or regular polygonal prism shape; A bottom plate provided at one end of the outer tube; a vibration absorbing section including one or more cylindrical or regular polygonal prism-shaped connecting tubes arranged coaxially with the outer tube and an elastomer filling section made of an elastomer filling the space between the tubes, the vibration absorbing section being located inside the other end of the outer tube; A fixture provided on the other end side of the center of the vibration absorbing part; an elastic body provided inside the outer tube for biasing the bottom plate and the vibration absorbing portion in a direction away from each other; having The thickness of each of the elastomer-filled portions is 4% or more and 25% or less of the maximum diameter of the outer tube, The elastomer-filled portion is a vibration-proof material that absorbs vibrations by being pulled by the connecting tube and the outer tube.

2. The elastic body is a coil spring, a recessed dish portion that receives and fixes the coil spring at the other end side of the center of the bottom plate; The vibration absorbing portion side of the coil spring is accommodated inside a central cylinder integrated with the fixing device. The vibration-isolating material according to claim 1.

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