JP2022170851A - Vibration control material - Google Patents

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

The present invention relates to a vibration isolator that absorbs vibration.

Various types of anti-vibration materials have been proposed for absorbing and supporting vibration, depending on the frequency of the vibration and the load to be supported. For example, as shown in FIG. 9(a), a vibration isolator 1 is used in which a cushioning part 2 made of a material having rubber elasticity is sandwiched between the upper and lower parts, and the material absorbs the vibration of the upper part.

As a technology similar to this, for example, Patent Literature 1 describes an anti-vibration structure in which two layers of rubber are used to receive vibrations and prevent vibrations from reaching pipes. It is used to support a compressor in a refrigeration cycle apparatus, and to provide vibration isolation while supporting a large load. There has also been proposed a vibration isolation structure in which a large number of layers are stacked, with more layers than in this example.

However, in such a vibration-absorbing material, when a load is applied in a shearing direction and a force is applied in a compressing direction, the hardness of the rubber that absorbs the vibration increases. As the rubber hardness increases, the natural frequency increases, and the lower limit of the absorbable vibration frequency increases. For example, when attached to a drone, even if it can absorb high-frequency vibrations of several tens of Hz or more due to the rotation of the wings, it cannot absorb low-frequency vibrations of 5 Hz or less due to the movement of the drone itself. In particular, when the anti-vibration structure is made up of multiple layers, it is easy to absorb horizontal vibrations due to the gap between the layers, but on the other hand, it becomes difficult to deform against vertical (compressive) loads, and the rubber hardness increases. becomes higher.

In order to absorb low-frequency vibrations even when the rubber that constitutes the anti-vibration material is subjected to a compressive force in the vertical direction, the original hardness of the rubber must be lowered. However, even if rubber with a rubber hardness as low as about 0 is used, the lower limit of the vibration frequency that can be absorbed is about 10 Hz. If the cushioning part 2 is made of such a soft rubber, even if it can absorb vibrations, it is too soft and is easily deformed as shown in FIG. I can no longer support it.

If a hollow air damper whose upper part is supported by a plate spring or the like is used instead of rubber, vibrations up to about 5 Hz can be absorbed. Patent Literature 2 proposes a shock absorber that has a hollow portion and is supported by rubber or a coil spring.

As another configuration, Japanese Patent Application Laid-Open No. 2002-300003 proposes a vibration isolation structure that supports vibrations in the vertical direction not by compressive stress but by tension. The load applied from above is absorbed by being pulled between the fixed outer periphery and the central portion that moves up and down instead of pressing the insulator rubber (7). For this reason, even if a load is applied, the rubber hardness of the insulator rubber does not increase, and the natural frequency can be maintained at a low level.

JP-A-11-2439 JP-A-63-72938 Japanese Utility Model Laid-Open No. 63-43887

However, the hollow-type vibration-damping member as disclosed in Patent Document 2 is unlikely to cause an increase in rubber hardness even when a load is applied. There is no directional support, it becomes difficult to fix, the whole thing moves, and it takes too long for the movement to converge. For example, in a factory line or the like, there is a problem that the front and rear relative positions move too much and the positions do not match.

In addition, the vibration isolation member described in Patent Document 3 absorbs vibrations only with the insulator rubber that is pulled. Therefore, even if an increase in the natural frequency can be avoided, absorption of vibrations in the horizontal direction is insufficient. There was also a problem with

Therefore, the present invention prevents the natural frequency from rising even in an environment where a load is applied, maintains a low natural frequency, supports low-frequency vibration isolation, and can exhibit support performance even against horizontal movement. The object is to realize a vibration-isolating material.

This invention
an outer cylinder having a columnar shape or a regular polygonal columnar shape;
a bottom plate provided at one end of the outer cylinder;
In the interior of the other end of the outer cylinder, one or more connecting cylinders in the shape of a cylinder or a regular polygonal cylinder, which are arranged coaxially with the outer cylinder, and an elastomer filling portion made of an elastomer that closes the space between the cylinders. a vibration absorbing portion having
a fixture provided on the other end side of the center of the vibration absorbing section;
an elastic body provided inside the outer peripheral cylinder that biases the bottom plate and the vibration absorbing portion in a direction away from each other;
The above problem was solved by the vibration-damping material having

Here, the above-mentioned interval between cylinders includes not only between the outer peripheral cylinder and the connecting cylinder, but also between the connecting cylinders when there are a plurality of connecting cylinders. In addition, when the innermost connecting cylinder is a central cylinder or a central column integrated with the fixture, the space between the central cylinder or the central column and the connecting cylinder is also included.

This anti-vibration material is mainly installed so that the bottom plate faces downward. Loads and vibrations from above are applied through the fixture. This load and vibration are absorbed by the elastomer-filled portion of the vibration absorbing portion being pulled between the cylinders. Since the load is applied in the tensile direction and not in the compressive direction, the hardness of the rubber constituting the elastomer-filled portion does not excessively increase, 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, but also by the urging force of the elastic body. To prevent.

Vibrations and loads applied to the elastomer-filled portion are distributed and absorbed by the connecting cylinder arranged coaxially with the outer cylinder without bias. As a result, distortion in the horizontal direction is less likely to occur, and not only can the vibration be absorbed, but also the shape stability can be maintained high.

Either a leaf spring or a coil spring can be used as the elastic body. An embodiment in which, when the coil spring is used, the coil spring is arranged so as to be positioned on the central axis of the outer cylinder, and 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. can be adopted. Further, it is preferable that the vibration absorbing portion side of the coil spring is housed inside the center tube that is integrated with the fixing member, because the coil spring can be fixed without shifting in the horizontal direction.

Furthermore, if there are a plurality of elastomer-filled portions between the cylinders and the number of divisions increases, the amount of deformation of each elastomer-filled portion can be reduced, and the spring constant in the vertical direction can be reduced. As a result, the natural frequency can be reduced, and the lower limit of the vibration frequency that can be absorbed can be lowered. In addition, horizontal displacement can be suppressed to a small extent, and the horizontal position can be easily maintained.

When the vibration isolator according to the present invention is used, it is possible to avoid an increase in rubber hardness due to load, so that it is possible to absorb lower frequency vibrations than the conventional vibration isolator laminated with elastomer. It can absorb vibrations in the frequency band from 1.4 times the natural frequency, and can absorb vibrations down to a low frequency of about 1.4 to 7 Hz depending on the combination of the coil spring and the elastomer filling portion. In addition, it can absorb low-frequency vibration not only in the vertical direction but also in the horizontal direction.

As a result, when mounted on a drone, for example, it is possible to absorb not only high-frequency vibrations caused by propeller rotation, but also low-frequency vibrations caused by large movements of the drone itself. By keeping it in place, you can greatly suppress the blurring of the drone image. In addition, in order to lower the natural frequency, it was necessary to apply a sufficient load, but with the anti-vibration material according to the present invention, the natural frequency is sufficiently small even in an environment with a light load such as a drone, and the low frequency can absorb up to the vibration of

In addition, even if it is installed in a situation where the load resistance continues for a long period of time, the load can be absorbed by the elastic body and the vibration absorbing part together, so the deterioration of the material hardly occurs and a long service life is realized. As a result, it exhibits a favorable effect as a vibration-damping material installed in a heavy object or a building that cannot be replaced over a long period of time. Since it can also absorb low-frequency tremors, it can also absorb vibrations caused by earthquakes to some extent.

(a) Perspective view of the vibration isolator according to the first embodiment of the present invention, (b) Front view of (a) (a) II-II cross-sectional view of FIG. 1(a), (b) plan view of FIG. 1(a) (a) Perspective view of vibration-damping material according to the second embodiment of the present invention, (b) Plan view of (a) Sectional view of a vibration-damping material according to a third embodiment of the present invention Schematic diagram of a drone equipped with anti-vibration material according to the present invention Graph showing the relationship between load and displacement in Examples 1 and 2 A photograph showing the state of the measurement of the natural frequency in Example 1 and a photograph of the display showing the measurement results A photograph showing the state of the measurement of the natural frequency in Example 2 and a photograph of the display showing the measurement results (a) A diagram showing an example of a conventional anti-vibration material, (b) an image diagram when (a) cannot maintain its shape

The present invention will be described in detail below. The present invention is a vibration isolator 11 that can receive vibration and load and absorb vibration.

A first embodiment of the vibration isolator 1 according to the present invention will be described as an example. A perspective view of the first embodiment is shown in FIG. The vibration isolator 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). FIG. 2(a) is a cross-sectional view along line II-II, and FIG. 2(b) is a plan view from above.

A vibration-damping material 11 according to the present invention has an outer peripheral tube 12 in the shape of a column or a regular polygonal column. 1 and 2 show an embodiment having a cylindrical outer cylinder 12 as an example. When it has a regular polygonal prism shape, it is preferably a regular pentagonal prism or more, more preferably a regular hexagonal prism or more. This is because if it is less than a regular square prism, the corners are small and the load and vibration are likely to be biased, the vibration absorbing effect is likely to be insufficient, and unexpected movement may occur. In the case of aligning the position with a fixing hole 22 (to be described later), it is preferable that the shape is a power of 2, such as a regular octagonal prism shape, because it is easy to arrange in terms of design. On the other hand, the more polygonal the shape, the less unevenness of the load, and the most preferable shape is a cylindrical shape in terms of durability and anti-vibration effect.

The material of the outer cylinder 12 can be appropriately selected depending on the application and size. Among resins, resins used for applications such as polycarbonate and ABS resins having relatively high strength and weather resistance are preferable to relatively brittle resins such as acrylic resins. Also, stainless steel, aluminum, or other metal castings may be used, or those formed by cutting may be used.

_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 isolator 11 has a large maximum diameter exceeding 1 meter, it may not be able to withstand the applied load unless a certain thickness is secured for the maximum diameter. Even if the maximum diameter is as small 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 will be distorted and the anti-vibration effect will be reduced, or it will not be able to withstand the load and break. In addition, the maximum diameter of the outer cylinder 12 here means the outer diameter of a circle in the case of a cylindrical shape, and the length of the diagonal of a regular polygon, which is the maximum length, in the case of a polygonal column. is. On the other hand, a thick portion is preferable in terms of durability, but if the thickness exceeds 15% of the outer diameter of the outer cylinder 12, it becomes difficult to sufficiently secure a space for providing the later-described connecting cylinder 14 and the elastomer filling portion 15. It is preferably 15% or less of the outer diameter of the outer cylinder 12 .

A vibration isolator 11 according to the present invention has a bottom plate 13 provided at one end of an outer cylinder 12 . Basically, the vibration isolator 11 is installed with the bottom plate 13 facing downward. Hereinafter, when referring to top and bottom, the side of the bottom plate 13 is referred to as the bottom. The bottom plate 13 may be integrated with the outer cylinder 12, or may be removable. However, if it is detachable, it is preferable to have a separate fixing mechanism so that it will not easily come off due to the force applied by the elastic body 18, which will be described later. The example shown in FIGS. 1 and 2 is an embodiment in which the outer cylinder 12 and the bottom plate 13 are integrated.

It is preferable that the bottom plate 13 can be fixed or fixed to other equipment provided below or to the floor surface. Specifically, it is desirable to have a fixed wing portion 21 protruding to the outside of the outermost periphery of the outer cylinder 12, or to be integrated with a plate for other purposes. Here, the plate for other uses includes a top plate of an object to which the vibration isolator 11 is to be attached, and the top plate can also be shaped to serve as the bottom plate 13 in the present invention. In the example shown in FIGS. 1 and 2 , two 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 cylinder 12 . The anchoring wings 21 are each provided with anchoring holes 22 to allow screwing to the instrument below.

The vibration isolator 11 according to the present invention includes one or more connecting cylinders 14 each having a cylindrical shape or a regular polygonal prism shape and arranged coaxially with the outer cylinder 12 inside the other end side of the outer cylinder 12, and a cylinder It has a vibration absorbing portion 16 having an elastomer filling portion 15 made of an elastomer that closes the gap. If any one of the outer cylinder 12 and the connecting cylinder 14 has a regular polygonal prism shape, it is desirable that the polygonal prisms have the same number of corners. For example, if regular hexagonal prisms and regular octagonal prisms coexist, there is a risk that vibration absorption will be biased, or that the coupling cylinders 14 will come into contact with each other depending on the angle, greatly reducing the vibration damping effect. At least the individual connecting cylinders 14 are arranged so as not to contact each other and also not to contact the outer peripheral cylinder 12, and elastomer filling portions 15 (15a, 15b, 15c, . . . ) are provided between the cylinders. ing.

In the embodiment shown in FIGS. 1 and 2, the connecting cylinder 14 has connecting cylinders 14a and 14b from the outside and a connecting cylinder (central cylinder) 14x integrated with a fixture 17 described later. The fact that these connecting cylinders 14 are arranged coaxially with the outer cylinder 12 means that they are arranged so that the central axis A of the cylinder or regular polygonal cylinder of the outer cylinder 12 and the central axis of each connecting cylinder 14 are aligned. is. When both the outer cylinder 12 and the connecting cylinder 14 are columnar, as shown in FIG. 2(b), the shape when viewed from above is concentric. On the other hand, if any one or more of the outer cylinder 12 and the connecting cylinder 14 are in the shape of regular polygonal prisms, it is desirable that the polygonal prisms have the same number of corners.

As an example, FIG. 3 shows a second embodiment in which both the outer peripheral tube 32 and the connecting tube 34 are regular octagonal prisms. FIG. 3(a) is a perspective view, and FIG. 3(b) is a plan view. In accordance with the shape of the cylinder, the elastomer-filled portion 35 is not circular, but has an octagonal prism-shaped outer circumference. By aligning the directions of the corners of the outer peripheral cylinder 32 and the connecting cylinder 34, the vibration can be stably absorbed without deviation even if force is applied from any direction.

The material of the connecting tube 14 is not particularly limited. It may be made of resin or metal. However, it is preferable that it does not deteriorate when it comes into contact with the elastomer-filled portion 15 . Moreover, it is more preferable that it can be firmly adhered to the elastomer-filled portion 15 .

The thickness (T ₂ , T ₃ , . . . ) 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 isolator 11 has a large maximum diameter exceeding 1 meter, it may not be able to withstand the applied load unless a certain thickness is secured for the maximum diameter. Here, the maximum diameter of the connecting tube 14 is the outer diameter of the circle in the case of a cylindrical shape, and the length of the diagonal line of the regular polygon, which is the maximum length, in the case of a polygonal column shape. . On the other hand, a thicker portion is preferable in terms of durability. of 15% or less. As long as durability in the environment of use can be ensured, basically the thickness of the connecting cylinder 14 can be reduced and the number of connecting cylinders 14 increased accordingly to lower the natural frequency, thereby enabling absorption. This is preferable because the lower limit of the frequency can be lowered. For example, if the maximum diameter is as small as centimeters, a resin film having a thickness of about 10 to 100 μm can be used as the connecting tube 14 . Even with the thin connecting tube 14, the effect of lowering the natural frequency is exhibited by repeating a structure in which the portion bonded to the elastomer filling portion 15 is pulled up and down.

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%, the connection tube 14 may 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 the elastomer filling portion 15 that connects the cylinders is small, and the effect of absorbing shock and vibration becomes insufficient.

The elastomer filling portion 15 fills the space between the cylinders with an elastomer. Examples of elastomers used here include urethane elastomers, ethylene elastomers, silicone elastomers, and the like. Natural rubber is not preferable because its rubber elasticity is too high. The elastomer filled portion 15 is pulled by the inner and outer cylinders, and by trying to return from the pulled state, it acts as a vibration isolator capable of absorbing even low-frequency vibrations. Vibration is converged by the elastomer filling portion 15 .

As a structure for bonding between the elastomer filling portion 15 and the outer cylinder 12 or the connecting cylinder 14, the elastomer and the outer cylinder 12 or the connecting cylinder 14 may be bonded with an adhesive, or the elastomer itself may be attached to the outer periphery. It may be firmly adhered to the tube 12 or the connecting tube 14 . These are put together to form the vibration absorbing portion 16 .

The _radial thicknesses W ₁ , W ₂ , W ₃ , . . . of the elastomer filled portions 15 (15a, 15b, 15c, . If the thickness is thinner than that of the connecting tube 14, the allowable width of the displacement in the vertical direction is too small, and it becomes difficult to obtain a sufficient anti-vibration effect. The thickness _Wx of each elastomer-filled portion 15 is preferably 2% or more, more preferably 4% or more, of the maximum diameter of the outer cylinder 12 . Also, although it depends on the maximum diameter of the outer cylinder 12, if it is less than 2%, the allowable width of the variation in the vertical direction is too small compared to the variation width required from the size of the outer cylinder 12. The anti-vibration effect tends to be insufficient. On the other hand, although the thickness is not particularly limited, it is preferable that the thickness of one elastomer-filled portion 15 is 25% or less of the maximum diameter of the outer cylinder 12, and 15% or less is a large number of layers of the elastomer-filled portion 15. It is more preferable to ensure If only one elastomer-filled portion 15 is too thick, there is a risk that the effect of multi-stage impact absorption by the connecting tube 14 provided in the middle may be biased or insufficient. _In addition, _each thickness W1, W2 _, W3 may be the same, and may differ.

As a procedure for forming such a vibration absorbing portion 16, for example, a frame is constructed in which the connecting cylinder 14 is arranged so that the axes of the connecting cylinder 14 are aligned in the outer peripheral cylinder 12, and a curable elastomer such as liquid urethane is placed there. There is a procedure for pouring the resin that will become and solidifying the whole. Although working accuracy is required for how to harden the frame, the elastomer filling portion 15 that fills the space between the cylinders is firmly connected to the outer cylinder 12 and the connecting cylinder 14, and high durability can be exhibited. As another procedure, after pouring a resin that becomes a curable elastomer into a frame in which the connecting cylinder 14 is arranged separately from the outer cylinder 12 and hardening it, the periphery of the elastomer filling part 15a is cut out, and the inner periphery of the outer cylinder 12 is removed. A procedure of attaching to and fixing with an adhesive is also included.

The vibration isolator 11 according to the present invention has a fixture 17 on the other end side (that is, the upper side) of the center of the vibration absorbing portion 16 . The fixture 17 is a part that can fix another member positioned above the vibration isolator 11 to the vibration isolator 11 . In the embodiment shown in FIGS. 1 and 2, it is integral with the internally threaded central tube 14x. Conversely, a form in which the male screw protrudes upward may be used. In the case of a configuration in which the male screw protrudes, the lower portion of the fixing member 17 may be a central column with no cavity or with a closed cavity in the middle, instead of the central tube 14x. Even in such a strictly non-cylindrical case, the circumference of the central column is similarly filled with the elastomer filling portion 15 described as the above-mentioned inter-cylinder space.

At least one, preferably two or more rotation fixing holes 24 are preferably formed in the side peripheral surface of the fixture 17 . Regardless of whether the fixture 17 is a male screw or a female screw, a force that tends to rotate the fixture 17 in a twisting direction acts when the fixture 17 is attached to another member arranged above. If this is left as it is, a force is applied in a twisting direction to the connecting tube 14 on the inner peripheral side, and a force is applied in a twisting direction to the elastomer-filled portion 15 by being pulled by it, and it may be fixed in a state of being twisted, or the thread may be cut off. There is a risk of For this reason, when applying a rotating force to attach another member to the male or female screw of the fixture 17, a rod-shaped member for fixing to the rotation fixing hole 24 is inserted from the side, and the fixture 17 and the center are inserted. The tube 14x is fixed so as not to rotate in the twisting direction. It is desirable that the inner periphery of the rotation fixing hole 24 is cut into a rectangular shape such as a square or a hexagon so that it does not slip. The illustrated embodiment is an example of hexagonal cutting.

The vibration isolator 11 according to the present invention has an elastic body 18 provided inside the outer peripheral tube 12 for urging the bottom plate 13 and the vibration absorbing portion 16 in the direction of separation. That is, it is provided in a space below the vibration absorbing portion 16 and above the bottom plate 13 . The elastic body 18 may be any one that can be biased in the vertical direction, such as a leaf spring or a coil spring. A coil spring is used in the embodiment shown in FIGS.

When the elastic body 18 is a coil spring, it is preferable to form a recessed dish portion 20 on which the coil spring is mounted and fixed so as not to move in the horizontal direction in the upper central portion of the bottom plate 13 so that the coil spring does not come off. Specifically, the recess may have a diameter slightly larger than the diameter of the coil spring. The depth of the dent is desirably equal to or greater than the thickness of one wire forming the coil spring, and more desirably equal to or greater than the thickness of two wires. If it is too shallow, even if there is a dent, the coil spring may be displaced and come off. On the other hand, if the upper end side of the coil spring is accommodated in the lower portion of the central cylinder 14x, the possibility of horizontal displacement is almost eliminated, which is preferable. However, in order to press the upper end of the coil spring, it is preferable that a reduced diameter portion 25 is provided in the middle of the central tube 14x. It is desirable that the radial width of the diameter-reduced portion 25 is equal to or greater than the thickness of one wire forming the coil spring.

If the elastic body 18 is a coil spring, it must be attached so that the length can be further contracted from the length at the time of attachment. If the spring is compressed to such an extent that the wires of the coil spring are in contact with each other, the vibration in the vertical direction cannot be absorbed sufficiently. On the other hand, the length when attached is not the original length when there is no load, but it is preferable to attach it so that the length as a spring is reduced by 5 to 50% and is in a compressed state, 20 to 50%. It is more preferable to attach it so that it is in a contracted compressed state. As a result, a force acts to urge the bottom plate 13 and the vibration absorbing portion 16 in the direction of separation. If the spring is introduced in a non-loaded state rather than a compressed state, the spring constant tends to increase due to the displacement caused by the load from above. However, if the spring is introduced in a compressed state, the spring constant of the vibration-isolating material as a whole rises slowly, and the natural frequency tends to approach zero.

The contents will be explained with specific numerical values. For example, assume a case in which a coil spring with a length of 10 mm is attached. A coil spring A having an original length of 15 mm and a relatively small spring constant of 0.1 kgf/mm and a coil spring B having an original length of 11 mm and a relatively large spring constant of 0.5 kgf/mm are used. Both of them require the same load of 0.5 kgf to shrink them to 10 mm. Therefore, if these are shortened to 10 mm and installed, both will support a load of 0.5 kgf. Suppose that a vibrational displacement is added to this well-balanced state in order to shrink it further by 1 mm, that is, to shorten it to a length of 9 mm. At this time, the repulsive resilience, which is the force to return to the original state, is 0.1 kgf/mm×1 mm in the case of the coil spring A, and only 0.1 kgf suffices. On the other hand, the coil spring B is 0.5 kgf/mm×1 mm, which is 0.5 kgf. That is, the coil spring B receives stronger repulsion. The weaker the restoring force of the vibration-damping material according to the present invention, the less likely it is that vibrations will be transmitted. Therefore, by adopting a coil spring having a small spring constant and introducing a coil spring having a long original length by shortening it by a certain length, vibration is less likely to be transmitted, and a preferable vibration isolator can be obtained.

In the embodiment shown in FIGS. 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 central tube 14x pulls the elastomer-filled portion 15c upward, making the upper surface oblique. ing. In addition, the connecting tube 14b is pulled by this, and the elastomer filled portion 15b is pulled upward, and the upper surface is slanted. Further, the upper surface of the elastomer filling portion 15a is also inclined by being pulled by the connecting tube 14a which is pulled by this. That is, the fixture 17 pushed by the central tube 14x is pushed upward.

It is preferable that the coil spring, which is the elastic body 18, has a smaller spring constant from the viewpoint of lowering the natural frequency. On the other hand, it is required to have a spring constant that can support the load to be supported depending on the application.

When another member is attached to the fixture 17 and a load is applied from above, the coil spring preferably has a margin that allows it to be further compressed by 5% or more of its original length. If the coil spring is completely compressed when a further load is applied from that state, the vibration absorption effect will not be sufficiently exhibited.

The vibration-absorbing material according to the present invention may have a plurality of stages of vibration-absorbing portions 16 inside the outer peripheral tube 12, as in the third embodiment whose cross-sectional view is shown in FIG. In this case, the coil springs, which are the elastic bodies 38 in the second and subsequent stages counted from the bottom, can be shaped such that the bottom thereof is fixed to the recessed dish portion 39 provided on the upper surface of the fixture 37 . By having the vibration absorbing portions 16 in multiple stages, there are cases where the effect of damping vibrations particularly in the vertical direction is exhibited more favorably than when one vibration absorbing portion 16 is vertically elongated.

The anti-vibration material according to the present invention is, for example, in a quadcopter drone 51 as shown in FIG. It is possible to use such as

(Example 1)
An example of the present invention will be specifically shown, but the present invention is not limited to this example. First, materials to be used are described.
・Elastomer 1……Hirakata Giken Co., Ltd.: Nobrene (rubber hardness 6 after curing)
・Elastomer 2……Hirakata Giken Co., Ltd.: Nobrene (rubber hardness 2 after curing)
・Connecting cylinder……Made of aluminum alloy, machined・Peripheral cylinder……Made of polycarbonate

_The thickness T1 of the outer cylinder and the thicknesses T2 and T3 of the connecting cylinders are ₁ mm, the diameter of the outer cylinder is ₃₀ mm, the diameter of the first connecting cylinder is 23 mm, the diameter of the second connecting cylinder is 16 mm, The connecting cylinder and the outer cylinder were arranged so that the thickness of the elastomer-filled portion was 2.5 mm. In addition, a fixture having 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 direction is arranged upside down from that in FIG. 1, and the periphery of the fixture is temporarily covered so as to be the bottom. The elastomer 1 before curing was poured into the outer cylinder until the height of the connecting cylinder was buried, and cured. After curing, the lid was removed, the top and bottom were turned back, the outer cylinder and the outermost elastomer-filled part were cut, and the vibration absorbing part was once removed from the outer cylinder. Next, the lower 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 is placed on the concave dish portion, and the upper end of the coil spring is fitted into the central tube in the center of the vibration absorbing portion. , and fixed between the outer cylinder and the elastomer-filled portion with an adhesive. At this time, a coil spring having a spring length of 10 mm was introduced as it was to complete the vibration isolator having the shape shown in FIG.

Four of these anti-vibration materials were installed so as to support the four corners of the plate on which the load was applied, and the plate and the anti-vibration material were fixed by screwing. A load was applied from above the plate to measure the load (N) when indicating the amount of displacement. Table 1 and the graph of FIG. 6 show the load at each displacement amount. It was confirmed that even if the load increases, the displacement increases proportionally. In addition, the spring constant increases as the amount of displacement increases with conventional gel-laminated anti-vibration materials, but with the anti-vibration material according to the present invention, the increase in spring constant is suppressed by the action of the elastomer-filled portion. Confirmed.

Next, a weight was placed on the plate, and a vibration analyzer (VA-12: Rion Co., Ltd.) was attached to measure the natural frequency. A photograph showing the measurement environment is shown in the upper part of FIG. 7, and a photograph showing the measurement results is shown in the lower part of FIG. In the lower graph of FIG. 7, the horizontal axis is the frequency, the vertical axis is the decibel, and the frequency showing the peak corresponds to the natural frequency. Even if the load increases and the spring is compressed, the natural frequency does not increase but decreases, demonstrating anti-vibration performance capable of absorbing vibrations up to nearly 10 Hz. In addition, even when vibrated, no horizontal deviation was observed, and it was confirmed that a stable posture was maintained.

(Example 2)
In Example 1, Elastomer 1 was changed to Elastomer 2, the coil spring was changed to have 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. A vibration-damping material having the same structure as in Example 1 was manufactured, except that it was introduced through the first step. Similarly, the graph in FIG. Even with the same amount of displacement as compared with Example 1, the amount of displacement was significantly smaller. This indicates that even when a light object with a smaller load than in Example 1 is placed, sufficient displacement is exhibited and vibration can be absorbed. This is considered to be the result of using a coil spring with a small spring constant and introducing the spring after increasing the amount of displacement by compressing the spring from its original size.

Next, the natural frequency was measured in the same manner as in Example 1. The results are shown in FIG. 8 and Table 4. Both the upper and lower photographs in FIG. 8 are photographs showing the measurement environment in the upper row as in FIG. 7, and the photographs in the lower row showing a graph in which the horizontal axis is the frequency and the vertical axis is the decibel. Compared with Example 1, the natural frequency was further reduced, and it was shown that even with a light load, it is possible to sufficiently absorb vibrations of a low frequency. From the tendency of Example 1, the natural frequency should be smaller when the load is 16.2N.

1 vibration isolator 2 cushioning part 11 vibration isolator 12, 32 outer tube 13 bottom plate 14, 14a, 14b, 34 connecting tube 14x central tube 15, 15a, 15b, 15c, 35 elastomer filling part 16 vibration absorbing part 17, 37 fixed Tools 18, 38 Elastic bodies 20, 39 Concave portion 21 Fixed wing portion 22 Fixing hole 24 Rotating fixing hole 25 Reduced diameter portion 51 Drone 52 Camera A Central axis

Claims (2)

an outer cylinder having a columnar shape or a regular polygonal columnar shape;
a bottom plate provided at one end of the outer cylinder;
In the interior of the other end of the outer cylinder, one or more connecting cylinders in the shape of a cylinder or a regular polygonal cylinder, which are arranged coaxially with the outer cylinder, and an elastomer filling portion made of an elastomer that closes the space between the cylinders. a vibration absorbing portion having
a fixture provided on the other end side of the center of the vibration absorbing section;
an elastic body provided inside the outer peripheral cylinder that biases the bottom plate and the vibration absorbing portion in a direction away from each other;
Anti-vibration material with the elastic body is a coil spring,
Having a recessed plate portion that receives and fixes the coil spring on the other end side of the center of the bottom plate,
The vibration isolator according to claim 1, wherein the vibration absorbing portion side of the coil spring is housed inside a central cylinder integrated with the fixture.

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