JP6382689B2 - Vibration isolator - Google Patents

Description

  The present invention relates to a vibration isolator that protects cargo (placed object) from impacts and vibrations that occur during the transportation and handling of cargo such as fine arts and precision equipment.

  An anti-vibration device used for an anti-vibration pallet that protects a mounted object from impacts and vibrations usually uses a spring function and a damper function together (see, for example, Patent Document 1).

  An analysis model of such a vibration isolator is shown in FIG. In FIG. 4, m is the mass of the vibrating body 100, k is the spring constant of the coil spring 200, C is the viscous damping coefficient of the oil damper 300, Fcosωt is a periodic external force acting on the vibrating body 100 (where F is the excitation) The amplitude of the force, ω is the angular frequency of the periodic external force).

The attenuation ratio ζ of the analysis model shown in FIG. 4 can be expressed by the following equation. FIG. 5 shows the relationship between the frequency ratio (ω / ω _n ) and the amplitude magnification (χ ₀ / χ _st ) at each damping ratio ζ.

  Here, since the viscous damping coefficient (C) of the oil damper is a material eigenvalue and the spring constant (k) of the coil spring 200 is a constant value, the mass (m) of the load represented by the vibrating body 100 is If it changes, the damping ratio (ζ) changes, and there is a problem that the image stabilization performance fluctuates as shown in FIG.

  In particular, since the anti-vibration pallet changes the mass (loading load) of the load in various ways, the anti-vibration performance fluctuates each time. Therefore, it is necessary to select a damping element each time the loading load changes.

JP 2007-278452 A

  An object of the present invention is to provide a vibration isolator whose damping ratio does not depend on a load.

The present invention has been made to solve the above-described problems, and has the following configuration.
(1) A base pedestal, a rubber bearing installed on the upper surface of the base pedestal and having a shaft insertion hole in the vertical direction, and a fiber and an elastomer integrated on the inner surface of the shaft insertion hole of the rubber bearing. A sliding membrane, a loading table installed on the upper surface of the rubber bearing, and a base that is provided on the upper surface of the base table or the lower surface of the loading table. An anti-vibration device comprising a shaft shorter than the vertical length of the hole.
(2) The vibration isolator according to (1), wherein the rubber support is a laminated rubber support in which a plurality of rubber layers and rigid plates are alternately stacked in the vertical direction.
(3) The anti-vibration device according to (2), wherein the rubber layer positioned at least at the portion where the shaft is inserted is formed thicker than the thickness of the rubber layer positioned at the portion where the shaft is not inserted.

When the rubber support is compressed by receiving a load, the rubber protrudes outward so as to draw an arc. In the present invention, the shaft inserted into the shaft insertion hole is pressurized with this protruding force, so that the rubber bearing body can reduce the vibration in the vertical direction, and thus the vibration-proof function is achieved. In particular, the force of protrusion increases as the mass (load) of the load increases, and the anti-vibration function also increases.
On the other hand, the sliding film provided on the inner surface of the shaft insertion hole generates a frictional force by sliding with the shaft fitted in the shaft insertion hole. A damper function is achieved by using this frictional force as a resistance force. In particular, when the applied load increases, the length of insertion of the shaft into the shaft insertion hole increases, so the frictional force increases and the damper function increases.
Therefore, the vibration isolator of the present invention has an effect that the damping ratio does not depend on the load. For this reason, it is not necessary to select a vibration isolator every time the load (baggage) changes, and it becomes easy to standardize the vibration isolator.

It is sectional drawing of the vibration isolator which concerns on one Embodiment of this invention. It is the schematic for demonstrating the function of the laminated rubber bearing body in one Embodiment of this invention. It is sectional drawing of the vibration isolator which concerns on other embodiment of this invention. It is an analysis model of a vibration isolator composed of mass, spring, and damping. 5 is a graph showing an amplitude magnification (χ ₀ / χ _st ) with respect to a frequency ratio (ω / ω _n ) in the analysis model shown in FIG. 4.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[One Embodiment of the Present Invention]
FIG. 1 shows a cross-sectional view of a vibration isolator 1 according to an embodiment of the present invention. The vibration isolator 1 has a structure in which a loading table 40 is installed on the upper surface of the base table 10 via a laminated rubber support 20. The laminated rubber support 20 has a shaft insertion hole 21, and a sliding film 30 in which fibers and elastomer are integrated is provided on the inner surface of the shaft insertion hole 21. The loading table 40 has a shaft 41 on the lower surface, and the shaft 41 is slidably inserted into the shaft insertion hole 21.

  As the base table 10 and the loading table 40, for example, in the case of a vibration-proof pallet, a lower frame and an upper frame that constitute the vibration-proof pallet can be used. Also good. The base table 10 and the loading table 40 can be attached to the lower frame and the upper frame with, for example, bolts and nuts.

(Laminated rubber bearing 20)
In the laminated rubber support 20, a plurality of rubber layers 22 and rigid plates 23 are alternately laminated between holding plates 24 and 25, and are integrally formed by a hot press.

The rubber layer 22 includes a vulcanizing agent, a vulcanization accelerator, a vulcanization acceleration aid, an anti-aging agent, a reinforcing agent, a retarder, a plasticizer, and a colorant as necessary, in the rubber component as a main component. It is a combination of agents.
Examples of the rubber component include diene rubber. Examples of the diene rubber include natural rubber; synthetic rubber such as chloroprene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, butadiene rubber, isoprene rubber, butyl rubber, and halogenated butyl rubber. Known ingredients can be used as the compounding agents such as a vulcanizing agent, a vulcanization accelerator, a vulcanization acceleration aid, an anti-aging agent, a reinforcing agent, a retarder, a plasticizer, and a colorant.

  Examples of the rigid plate 23 include a metal plate such as a steel plate, a ceramic plate, and a hard plastic plate. What is necessary is just to adjust the thickness of the rigid board 23 suitably according to the use application etc. of the vibration isolator 1. FIG.

  The holding plates 24 and 25 are not particularly limited as long as they can fix the laminated rubber support 20, the base 10 and the loading table 40 by adhesion or the like.

  As shown in FIG. 1, the rubber layer 22 (the rubber layer 22 in the shaft insertion portion 20A) located on the upper surface side of the laminated rubber bearing 20 into which the shaft 41 is inserted is the rubber layer 22 (the shaft It is formed thicker than the rubber layer 22) in the non-insertion portion 20B. The length of the rubber layer 22 in the shaft insertion part 20A is preferably substantially the same as the length of the shaft 41 described later.

  The thickness and the number of laminated layers of the rubber layer 22 in the insertion portion 20A and the non-insertion portion 20B are determined in consideration of the load applied to the loading table 40 and the like.

  The laminated rubber support 20 is a cylinder having a shaft insertion hole 21 penetrating in the vertical direction. The horizontal cross-sectional shape of the shaft insertion hole 21 is determined in accordance with the horizontal cross-sectional shape of the shaft 40 fitted into the shaft insertion hole 21. In order to obtain a high anti-vibration effect, the horizontal cross-sectional shape of the shaft insertion hole 21 is preferably circular, but is not limited thereto, and may be a rectangle, a polygon, or the like.

The number of shaft insertion holes 21 is not limited to one at the center of one laminated rubber bearing body 20, and two or more shaft insertion holes 21 may be provided depending on the number of shafts 40.
Although the laminated rubber support 20 shown in FIG. 1 is formed of a cylindrical body in which the shaft insertion hole 21 penetrates in the vertical direction, the shaft insertion hole does not necessarily have to penetrate the laminated rubber support.

(Sliding membrane 30)
The sliding film 30 is formed by integrating fibers and an elastomer, and is disposed on the inner peripheral surface of the laminated rubber support 20. The sliding film 30 exhibits a damper function that uses the frictional force with the shaft 41 as a resistance force when the shaft 41 slides.

  The elastomer constituting the sliding film 30 mainly improves the durability of the fiber. Examples of the material of the elastomer constituting the sliding film 30 include natural rubber, nitrile rubber, chloroprene rubber, hyperon, polybutadiene rubber, ethylene-propylene rubber (EPM), and ethylene-propylene-diene terpolymer (EPDM). , Elastomers such as hydrogenated acrylonitrile butadiene rubber (H-NBR), silicon rubber, fluorine rubber, acrylic rubber, styrene butadiene rubber, chlorinated polyethylene rubber, millable urethane, thermosetting polyurethane, thermoplastic polyurethane or thermoplastic polyester One or more of these are used. The elastomer constituting the sliding film 30 may be blended with a vulcanizing agent, a vulcanization acceleration aid, and a reinforcing agent.

  Examples of the vulcanizing agent include organic peroxides such as dicumyl peroxide, organic sulfur compounds, and metal oxides. Examples of the vulcanization acceleration aid include fatty acids such as stearic acid, metal oxides, and the like. Examples of the reinforcing agent include carbon black and white carbon. Furthermore, for example, anti-aging agents, fillers, plasticizers, pressure-sensitive adhesives and the like can also be blended. In addition to these, in order to reduce the sliding resistance with the shaft 41, a solid lubricant such as graphite, silicone oil, fluorine powder, or molybdenum disulfide may be included in the elastomer.

Examples of the fibers constituting the sliding film 30 include nylon fibers, aramid fibers, polyester fibers, carbon fibers, Teflon (registered trademark) fibers, liquid crystal polymer fibers, glass fibers, and cotton yarns. The fibers constituting the sliding film 30 may be in the form of a cloth material or may be mixed with the elastomer in the form of short fibers.
Examples of the cloth material include woven cloth, knitted cloth, and non-woven cloth. Although the fabric weight of a cloth material is 20-200 g / m < ² > normally, it is not specifically limited.

  When the form of the fiber is a cloth material, the cloth material and the elastomer are integrated so that the cloth material slides in contact with the outer peripheral surface of the shaft 41. On the other hand, when the form of the short fiber is used, the short material is short in the elastomer. The sliding film 30 is obtained by mixing the fibers and integrally forming them.

  The ratio of the fiber and the elastomer can be appropriately determined so that an appropriate frictional force can be generated between the sliding film 30 and the shaft 41.

The thickness of the sliding film 30 (the thickness in the radial direction of the shaft insertion hole 21) is preferably a thickness that does not impair the vibration-proof function caused by the protruding of the laminated rubber bearing body 20.
Moreover, although the sliding film 30 is arrange | positioned at the whole inner surface of the shaft insertion hole 21, only a shaft insertion part may be sufficient, for example.

(Shaft 41)
The loading table 40 includes a mounting portion 42 and a shaft 41 formed on the lower surface of the mounting portion 42. The length of the shaft 41 is shorter than the length of the shaft insertion hole 21 in the vertical direction. Specifically, it is determined according to the applied load and the magnitude (variation width) of vibration in the vertical direction. Specifically, the shaft 41 has a bottom (the top surface of the base table 10 in the present embodiment) that is the bottom of the shaft 41 in the size (variation width) when the assumed maximum vibration is applied. The length is not reached.
The shaft 41 is provided at a substantially central portion of the mounting portion 42, but is not limited to this, and a plurality of shafts 41 are arranged at appropriate intervals in the loading portion 42 corresponding to the shaft insertion hole 21. May be provided.

〔Production method〕
In the vibration isolator 1, for example, after the laminated rubber support 20 having the sliding film 30 provided on the inner surface is installed on the upper surface of the base table 10, the shaft 41 formed on the lower surface of the loading table 40 is inserted into the shaft insertion hole 21. Manufactured by insertion.
At that time, the holding plate 24 is attached to the base table 10 by screwing, bonding or the like, and the laminated rubber support 20 and the base table 10 are fixed. The holding plate 25 is also attached to the loading table 40 in the same manner. Since the holding plates 24 and 25 are not necessarily required, they may be omitted.

  The laminated rubber bearing body 20 provided with the sliding film 30 on the inner surface can be manufactured by the following procedure. First, unvulcanized rubber is rolled and formed into a sheet shape, punched into a predetermined shape (in this embodiment, a donut shape), and then alternately laminated with a rigid plate 23 in a mold (not shown). On the other hand, the cloth material impregnated with the elastomer is disposed on the inner peripheral surface of the laminated body laminated as described above. Thereafter, the laminated rubber support 20 provided with the sliding film 30 can be obtained by pressure molding with a vulcanizing press.

  For the impregnation treatment of the cloth material with the elastomer, a method of impregnating the cloth material after dissolving the elastomer with a solvent or the like to form a liquid is preferably used. By impregnating the cloth material with the elastomer, the elastomer can enter between the fiber materials constituting the cloth material, and the fiber materials constituting the cloth material can be bonded together to reinforce the cloth material.

  The loading table 40 includes, for example, a method in which a female screw portion is formed on the lower surface of the mounting portion 42 and a male screw portion formed on the upper end of the shaft 41 is screwed into the female screw portion and integrated. It can be manufactured by a method of cutting out a lump of material to be processed.

[Action]
The vibration isolator 1 performs the following operations (a) to (d).
(A) When the load is placed on the mounting table 40, a vertical downward load is applied to the vibration isolator 1, and the rubber layer 22 is formed on the outer surface of the laminated rubber support 20 and the shaft insertion hole 21 due to its incompressibility. Trying to swell to the inside.
FIG. 2 is a schematic view showing a state in which a vertically downward load W is applied. The laminated rubber support 20 has a thick rubber layer 22 (that is, a rubber layer at the shaft insertion portion) and a thin rubber layer. Compared to 22 (that is, the rubber layer at the shaft non-insertion site), the outer surface and the inner surface of the laminated rubber support 20 are greatly protruded (the difference in swelling is indicated by d).
(B) Since the outer surface of the laminated rubber bearing 20 has nothing to control the swelling of the rubber layer 22, the rubber layer 22 protrudes freely. On the other hand, the bulge into the shaft insertion hole 21 is in a state where the shaft 41 is pressed through the sliding film 30 because of the shaft 41. The rubber layer 22 in the shaft insertion portion 20A exhibits such a behavior remarkably.
(C) At this time, when the load W increases, the pressing force P against the shaft 41 increases. Due to this pressing force P, the vertical vibration V shown in FIG. 1 is reduced.
(D) When there is vibration V in the vertical direction, the laminated rubber bearing 20 vibrates up and down, and a frictional force is generated between the sliding film 30 and the shaft 41 accordingly. A damper function is exhibited by using this frictional force as a resistance force.
As described above, by using the force that protrudes from the inner surface of the rubber layer 22 and the frictional force of the sliding film 30, it is possible to prevent vibration whose damping ratio does not depend on the load. For this reason, for example, when applied to a vibration-proof pallet, it can have a certain usable width with respect to the load.

[Other Embodiments]
FIG. 3 shows a cross-sectional view of a vibration isolator 2 according to another embodiment of the present invention. The vibration isolator 2 is the same as the vibration isolator 1 shown in FIG. 1 except that the thickness of the rubber layer 22 constituting the laminated rubber support 26 is all equal.

In addition, this invention is not limited to the said embodiment, For example, it replaces with the laminated rubber support bodies 20 and 26, and may use the rubber support body which consists of rubber materials which does not use the rigid board 23. FIG. Also in this case, by using the force that protrudes from the inner surface of the rubber support and the frictional force of the sliding film 30, it is possible to prevent vibrations whose damping ratio does not depend on the load.
Moreover, in the said embodiment, although the shaft 41 was provided in the lower surface of the loading base 40, even if it provides in the upper surface of the base base 10 and this is slidably inserted in the shaft insertion hole 21, it is the same effect. Is obtained.

DESCRIPTION OF SYMBOLS 1, 2 Vibration isolator 10 Base stand 20,26 Laminated rubber support body 21 Shaft insertion hole 22 Rubber layer 23 Rigid board 30 Sliding film 40 Loading stand 41 Shaft 100 Vibrating body 200 Coil spring 300 Oil damper

Claims (3)

A base stand,
A rubber bearing body installed on the upper surface of this base table and having a shaft insertion hole in the vertical direction;
A sliding membrane provided on the inner surface of the shaft insertion hole of the rubber bearing body, in which fibers and an elastomer are integrated;
A loading platform installed on the upper surface of the rubber bearing;
A shaft provided on the upper surface of the base table or the lower surface of the loading table, slidably fitted into the shaft insertion hole, and a length shorter than the vertical length of the shaft insertion hole;
An anti-vibration device comprising:   The vibration isolator according to claim 1, wherein the rubber support is a laminated rubber support in which a plurality of rubber layers and rigid plates are alternately stacked in the vertical direction.   The vibration isolator according to claim 2, wherein the rubber layer positioned at least at the portion where the shaft is inserted is formed thicker than the thickness of the rubber layer positioned at the portion where the shaft is not inserted.

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