JP2006161388A - Vibration-proofing method of structure floor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration-proofing method of a structure floor capable of efficiently exhibiting a vibration-proofing effect by realizing oscillating offset using the phase difference over single exciting force and, at the same time, being carried out on the floor wherein any gap and uneven step do not occur. <P>SOLUTION: The structure floor 1 is supported by combining the first propagation course 10 by a vibration-proof material 2 with the second propagation course 11 by a vibration-proof material 4 holding a mass body 3 in an intermediate section, the exciting force acting on the structure floor 1 is made to transfer to an under floor structure 5, the second propagation course 11 is constituted of a plurality of propagation courses 11 etc. respectively having different natural frequencies, and the vibration is negated by using the phase difference between a phase of vibration propagated to the under-floor structure 5 from the first propagation course 10 and a phase of vibration propagated to the under-floor structurre 5 from the second propagation course 11. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention belongs to the technical field of a structural floor vibration isolation method, and more particularly, relates to an improved vibration isolation method for the structure floor according to Japanese Patent Application Laid-Open No. 2004-251064 by the present applicant.

  Conventional anti-vibration technology introduces anti-vibration technology, such as anti-vibration support for the entire floor where the excitation force acts, using anti-vibration materials, thereby avoiding resonance and reducing the structure under the floor (foundation, ground, etc.). Reduction of vibration transmissibility has been attempted (for example, see Patent Documents 1 to 3).

  However, the anti-vibration techniques disclosed in Patent Documents 1 to 3 have problems as disclosed in paragraphs [0013] to [0015] of Japanese Patent Application Laid-Open No. 2004-251064 (see Patent Document 4) by the present applicant. In order to solve this problem all at once, the present applicant has developed a vibration isolation method for a structural floor according to Patent Document 4.

  The vibration isolating method for the structure floor according to Patent Document 4 is configured by combining the floor of the structure with an anti-vibration area that is anti-vibration supported with respect to an excitation force and a non-vibration-proof area that is not anti-vibration supported. The phase of vibration transmitted from the vibration-proof area to the underfloor structure is delayed, and the vibration is canceled out using the phase difference from the vibration transmitted from the non-vibration-proof area to the under-floor structure (see claim 1). As shown in FIG. 5 of Patent Document 4, f is the vibration frequency and fn is the natural frequency of the floor, as shown in FIG. In this case, it can be seen that a remarkable anti-vibration effect (vibration transmission rate when Fs is a transmission force and Fs0 is an excitation force: Fs / Fs0) is obtained in the range of 0 <f / fn <2.

  Therefore, according to the vibration isolation method for a structure floor according to Patent Document 4 by the present applicant, as described in [Effects of the present invention], (1) the floor of a structure on which an excitation force acts Anti-vibration effect can be achieved by supporting only a part of the anti-vibration effect, and since it can be implemented with a simple structure, it is excellent in economic efficiency. (2) Anti-vibration occupies the structure floor where the excitation force acts Regardless of the ratio of the area, the excitation frequency of the excitation force, and the difference in the phase of the excitation force, it is possible to achieve an anti-vibration effect, so that there are effects such as excellent flexibility, Useful (see paragraph [0068] of Patent Document 4). Further, as can be seen from FIG. 5 of Patent Document 4, the maximum value (peak) of the vibration transmissibility can be reduced as compared with the prior art, and the overall value of the vibration transmissibility can be reduced. In addition to being able to easily implement the anti-vibration support structure with a general-purpose anti-vibration material such as the above, it is excellent in that the habitability can be improved (see particularly paragraph [0033] of Patent Document 4).

  However, the technique disclosed in Patent Document 4 can be applied to a case where an excitation point acts on a plurality of different points, that is, a case where a large number of humans perform a jumping motion, and the like. It can be said that the vibration could not be canceled by generating a phase difference under the condition of one excitation source, such as the vibration generated by the operation of one large press. In addition, as shown in FIG. 12 of Patent Document 4, the technique according to Patent Document 4 generates a gap in a portion that divides the vibration-proof area and the non-vibration-proof area, and when used as a floor for the same application, Processing such as filling the gap with a finishing material was necessary. Furthermore, compared to a hard supported non-vibration-proof area, the floor of the anti-vibration area may cause large dynamic deformation due to the action of an excitation force. As a result, there is a risk that a difference in level occurs, and there is a need to place restrictions on use as a floor for the same purpose.

  By the way, the technique which concerns on patent document 5 is disclosed as a method of canceling a vibration by dividing | segmenting the propagation path which consists of support materials into two with respect to the excitation force of an exhaust pipe, and producing a phase difference. . The vibration model according to this vibration isolation technique is as shown in FIG.

  According to the technique according to Patent Document 5, as in Patent Document 4, since the vibration is canceled using the phase difference, a high effect can be obtained in the vibration reduction effect. Therefore, if this anti-vibration technology for the exhaust pipe is applied to the anti-vibration technology for the structure floor, the phase difference can be obtained even if there is only one excitation source without dividing the anti-vibration area into the non-vibration-proof area. It is possible to cancel the vibrations by generating, and it can be implemented without any restrictions as a floor for the same application.

Japanese Patent Publication No.3-3818 Japanese Examined Patent Publication No. 4-58865 JP-A-8-53954 JP 2004-251064 A JP-A-4-347321

  However, the anti-vibration technique according to Patent Document 5 does not consider the vibration amplification peak. That is, when the vibration transmissibility curve as shown in FIG. 5 of Patent Document 4 is obtained, in order to further reduce the minimum value of the illustrated curve, it is necessary to reduce the attenuation. The anti-vibration technique according to Patent Document 5 has a problem that the amplification peak is increased. That is, in the anti-vibration technique according to Patent Document 5 described above, when the vibration frequency such as vibration caused by human movement fluctuates, when the frequency of the amplification peak and the vibration frequency coincide, There was a risk of vibration disturbance.

  Further, since the vibration isolating technique according to Patent Document 5 is directed to the exhaust pipe, locking due to a difference in the spring stiffness of the propagation path is not so much of a problem. On the floor of a structure such as a floor slab, rotational vibration due to rocking is generated, which inevitably has an unstable structure.

  Therefore, the anti-vibration technology for the exhaust pipe according to Patent Document 5 cannot be applied as it is to the anti-vibration technology for the structural floor.

  An object of the present invention is to efficiently perform vibration cancellation using a phase difference for a single excitation force, which was not possible with the vibration isolation method for a structural floor disclosed in Patent Document 4 by the present applicant. An object of the present invention is to provide a vibration isolating method for a structure floor that can exhibit an anti-vibration effect and can be carried out on a floor surface that does not cause gaps and steps.

  Another object of the present invention is to provide a structure floor that can reduce the vibration amplification peak so that vibration disturbance does not occur even for a variable excitation frequency caused by a large number of human movements and can suppress rotational vibration caused by rocking. It is to provide a vibration isolation method.

As a means for solving the problems of the prior art, the vibration isolating method for a structure floor according to the invention described in claim 1 is as shown in FIG.
The floor 1 of the structure is supported by a combination of a first propagation path 10 by the vibration isolator 2 and a second propagation path 11 by the vibration isolator 4 with the mass body 3 sandwiched between the intermediate parts. Propagating the excitation force acting on the floor 1 to the underfloor structure 5;
The second propagation path 11 is composed of a plurality of propagation paths 11 having different natural frequencies, and the phase of vibration propagated from the first propagation path 10 to the underfloor structure 5 and the second propagation path The vibrations are canceled out using a phase difference from the phase of the vibrations propagated from 11 to the underfloor structure 5.

  According to the second aspect of the present invention, in the vibration isolating method for the structure floor according to the first aspect, as shown in FIG. It is a propagation path by the vibration material 2 and is not matched with any natural frequency of the second propagation path 11.

  The invention described in claim 3 is the first and second vibration transmissibility obtained by dividing the transmission force to the underfloor structure 5 by the excitation force in the vibration isolating method for the structure floor described in claim 1 or 2. By tuning the natural frequency, damping constant and number, and excitation force distribution ratio of the propagation paths 10 and 11 in any combination, the maximum and minimum values of the vibration transmissibility and the shape of the transmissibility curve can be freely adjusted. It is characterized by designing.

According to the vibration isolating method for a structure floor according to the present invention, in addition to the effects exhibited by the vibration isolating method for a structural floor disclosed in Patent Document 4 according to the present application, the following effects are exhibited.
1) Even for a single excitation source, it is possible to generate a phase difference in the excitation force propagated to the lower structure 5 and cancel out the vibrations, thereby realizing an excellent vibration isolation method and vibration. It is possible to carry out by setting a wide range of excitation force conditions to be reduced.
2) Since it can be carried out on the floor surface where no gaps and steps are generated, the range of application can be greatly expanded.
3) The vibration amplitude peak can be reduced so that no vibration disturbance occurs with respect to the variable excitation frequency caused by the movement of many humans.
4) Rotational vibration due to rocking due to a difference in spring stiffness of the propagation path can be suppressed.

  The vibration isolation method for a structure floor according to the present invention is carried out as follows in order to achieve the effects of the above-described invention.

FIG. 1 shows an embodiment of a vibration isolation method for a structure floor according to claim 1.
The vibration isolating method for the structure floor is such that the floor 1 of the structure is divided into a first propagation path 10 by the vibration isolation material 2 and a second propagation path 11 by the vibration isolation material 4 with the mass body 3 sandwiched between the intermediate portions. The excitation force acting on the floor 1 of the structure is propagated to the under-floor structure (foundation, ground, building floor, etc., the same applies hereinafter) 5 and the second propagation. The path 11 is composed of a plurality of propagation paths 11 having different natural frequencies, and the phase of vibration propagated from the first propagation path 10 to the underfloor structure 5 and the second propagation path 11. The present invention is characterized in that the vibrations are canceled out using a phase difference from the phase of the vibration propagated to (invention of claim 1).

  Specifically, the excitation force acting on the structure floor 1 includes the first propagation path 10 via the coil spring (vibration isolation material) 2, the mass body 3, and the upper and lower coil springs (vibration isolation materials). 4 is distributed to the second propagation path 11 via 4, propagated to the underfloor structure 5, and cancelled. Incidentally, the anti-vibration method of the illustrated example has a total of four first propagation paths 10 arranged at the four corners of the structure floor 1 and a second propagation path 11 adjacent to the center. Arranged and implemented. Further, a total of eight coil springs 4 used for the second propagation path 11 are installed at the upper and lower four corner positions of the mass bodies 3 and 3. Incidentally, reference numeral 6 in FIG. 1 denotes a coil spring fixing member, and reference numeral 7 denotes a support member. The vibration isolator 2 is not limited to a coil spring, and can of course be implemented by a general-purpose vibration isolator such as an air spring.

  The ratio of the excitation force distributed in the first and second propagation paths 10 and 11 (excitation force distribution ratio) is determined by the hardness of each propagation path 10 and 11 and the structure floor 1 on which the excitation force acts. And the ratio of the mass of the mass body 3 used in the second propagation path 11 can be determined. In other words, the excitation force distribution ratio is equal to the ratio of the excitation force (excitation force sharing ratio) shared by the vibration-proof area and the non-vibration-proof area described in the specification of Patent Document 4 by the applicant. It is equivalent.

  Incidentally, the anti-vibration method in the illustrated example is implemented in a bilaterally symmetric shape so as to suppress rotational vibration due to ronking as much as possible.

  The frequency and damping constant of the first propagation path 10 correspond to the frequency and damping constant of the non-vibration-proof area described in Patent Document 4, and the frequency and damping constant of the second propagation path 11 are the same. Furthermore, it corresponds to the frequency and damping constant of the vibration-proof area.

  The vibration isolation technique according to the present invention sets the excitation force distribution ratio, the frequencies of the first and second propagation paths 10 and 11 and the damping constant to optimum values according to the vibration characteristics to be reduced. Yes. The frequency and the damping constant are parameters that can be set by individually changing the mass, stiffness, and damping elements in the first and second propagation paths 10 and 11, and the types of members constituting the elements are: The invention is not particularly limited, and can be freely selected according to the frequency characteristic to be reduced (the invention according to claim 3). For example, the shape of the transmissibility curve required for the vibration characteristic to be vibrated is a curve shape obtained when the attenuation of the first propagation path 10 is zero, that is, when the attenuation element of the first propagation path 10 is omitted. If present, the damping element can be eliminated.

  The vibration reduction effect according to the present invention will be described below with specific examples.

  2A to 2C are graphs showing the frequency characteristics with respect to the vibration reduction rate in the vibration isolation technology according to the present invention. FIG. 2A shows a case where the second propagation path 11 is not divided (corresponding to the anti-vibration technique according to Patent Document 5). As an example, in order to make the vibration transmissibility 0.2 times at a frequency of 2.5 Hz, the vibration transmissibility at the amplification peak must be set to be about 3.5 times.

  In the operation of adjusting to human music or the like, which is one of the application ranges of the vibration isolation technology according to the present invention, the vibration frequency changes depending on the music pitch, and 2 to 3 Hz is the vibration that is most easily moved in accordance with the music. It is said to be a number. However, depending on the case, even a song with a frequency of 2.0 Hz or less may exhibit a certain large excitation force, and it can be said that the higher the amplification factor, the higher the possibility of a vibration complaint. In that regard, as will be described below, the image stabilization technique according to the present invention causes a cancellation phenomenon using a phase difference, and can reduce the amplification factor of the amplification region without impairing the performance of reducing vibration. it can.

  In order to solve the problem of reducing the amplification factor of the amplification region while maintaining the vibration reduction performance, the anti-vibration technology according to the present invention is, in other words, the mass body in the propagation path according to Patent Document 5 described above. Dividing the containing side into a plurality of parts (two or four as an example), and optimally setting each divided frequency, damping constant, and excitation force distribution ratio according to the frequency characteristics to be reduced It is a featured technology.

  For comparison with FIG. 2A (corresponding to Patent Document 5 above), this means that the second propagation path 11 is divided into two parts (two bodies are provided) with respect to the vibration frequency f = 2.5 Hz. 1) (see the model diagram of FIG. 3), and when divided into four (see the model diagram of FIG. 4), the vibration transmissibility is reduced by a factor of 0.2 and the gain is increased. Results optimally set to be small are shown in FIGS. 2B and 2C, respectively.

  2A is compared with FIG. 2B and FIG. 2C, in the case of FIG. 2A in which the second propagation path 11 is not divided, the maximum value of the vibration transmissibility (amplification factor) which is 3.5 times is 2 It can be seen that the frequency is reduced to about 2.1 times when divided, and about 1.4 times when divided into four (see FIGS. 2A to 2C).

  As described above, by dividing the second propagation path 11 into a plurality of parts, it is possible to reduce the amplification factor while maintaining the reduction rate with respect to the frequency. Incidentally, as an example, FIGS. 2A to 2C show an excitation force distribution ratio of the excitation force propagated from the first propagation path 10 and the sum of the excitation forces propagated from the second propagation path 11 as 1. It is the result of the study that was set to 1. Of course, by further setting the excitation force distribution ratio of the first and second propagation paths 10 and 11 and the excitation force distribution ratio of each distributed second propagation path 11, further reduction of the amplification factor can be achieved. (Invention of claim 3).

  In this embodiment, two examples of two divisions and four divisions are given. As is clear from comparison between FIG. 2B and FIG. 2C, four divisions reduce the amplification factor more than two divisions. I understand that Thus, the amplification factor can be further reduced by increasing the number of divisions (the number of second propagation paths 11) (the invention according to claim 3). In this embodiment, the number of divisions is divided into two and four. However, the present invention is not limited to this, and it is of course possible to increase the number of divisions as necessary.

  Regarding the fluctuation of the attenuation, graphs showing the frequency characteristics with respect to the vibration transmissibility are shown in FIGS. 5 indicates the frequency characteristics when the second propagation path 11 is not divided, and indicates the same line as FIG. 2A. Symbol Y in FIG. 5 indicates the frequency characteristic when the attenuation of the second propagation path is 0.5 times. From FIG. 3, the transmission rate at a frequency of 2.5 Hz is 0.2 times in the X curve, whereas it is reduced to about 0.1 times in the Y curve in which the attenuation is 0.5 times. I understand that. It can also be seen that the maximum value of the transmission rate is amplified from 3.5 times to 6.8 times.

  On the other hand, when the second propagation path 11 according to the present invention is divided into two, when the attenuation of both of the divided propagation paths 11 is 0.5 times, the result of the same examination is shown in FIG. 6. 6 indicates the frequency characteristics when the second propagation path 11 is divided into two, and indicates the same line as in FIG. 2B. The symbol Y in FIG. 6 shows the frequency characteristics when the attenuation is 0.5 times in each of the second propagation path 11 divided into two. From FIG. 10, the X curve shows that the vibration transmissibility at a frequency of 2.5 Hz is 0.2 times, whereas the Y curve where the attenuation is 0.5 times is reduced to about 0.1 times. Thus, the result is almost the same as when the second propagation path 11 is not divided. In addition, the maximum value of the transmissibility is amplified from 2.0 times to 4.0 times, which is lower than the case where the second propagation path 11 is not divided, but is kept at a lower level than the case where the second propagation path 11 is not divided. It can be said that

  Next, the results of varying the attenuation by 0.5 times for only one of the one set to a higher natural frequency and the one set to a lower one among the two divisions of the second propagation path 11 are shown in FIGS. 7 and 8, respectively. Shown in

  From FIG. 7, when the attenuation of the second propagation path 11 with the higher natural frequency is 0.5 times, the minimum value of the vibration transmissibility at a frequency of 2.5 Hz is 0.12 times. Compared to the fact that the minimum value when the second propagation path 11 is not divided is 0.1 times (see the Y curve in FIG. 5), the robustness is slightly improved. I understand. The maximum value of the vibration transmissibility is amplified from 2.0 times to 4.0 times as in the case where the attenuation of both propagation paths is 0.5 times (see the Y curve in FIG. 6). It can be said that the lower level is maintained than when the propagation path is not divided (the invention according to claim 3).

  From FIG. 8, when the attenuation of the second propagation path 11 with the lower natural frequency is 0.5 times, the minimum value of the vibration transmissibility of the frequency 2.5 Hz is from 0.2 times. It can be seen that there is almost no fluctuation and the robustness is improved. It can also be seen that the maximum value of the vibration transmissibility is only amplified from 2.0 times to 3.0 times, and the robustness is improved.

  The above-described result is a result in the case where the mass of the structure floor 1 on which the excitation force acts is lighter than the mass of the mass body 3 in the second propagation path 11. When the mass of the structure floor 1 on which is applied increases, the shape of the vibration transmissibility curve also changes, and the influence of the attenuation of the first propagation path 10 needs to be considered.

  As an example, when the mass ratio of the mass of the structure floor 1 on which the excitation force acts and the mass of the mass body 3 of the second propagation path 2 is 1: 9, the first and second propagation paths 10, FIG. 9 shows a plot of vibration transmissibility when the attenuation of 11 is varied by 0.5 to 2.0 times. FIG. 10 is a plot of vibration transmissibility when the attenuation of only the second propagation path 11 is varied by 0.5 to 2.0 times. FIG. 11 shows the attenuation of the first propagation path 10. The vibration transmissibility when fluctuating to 0.5 to 2.0 times is shown.

  9 to 11, it can be seen that the vertical axis of the shape of the vibration transmissibility curve can be freely manipulated depending on the magnitude of attenuation in the propagation paths 10 and 11. Further, as can be seen from FIG. 11, since the influence on the vibration transmissibility curve due to the magnitude of the attenuation of the first propagation path 10 is almost small, from the viewpoint of the excitation force transmitted to the underfloor structure 5, the first It can be said that the attenuation element of the propagation path 10 can be omitted. However, from the viewpoint of suppressing the displacement amplitude of the structure floor 1 on which the excitation force directly acts, a method of arranging a damping element in the first propagation path 10 and utilizing it effectively can be considered.

  FIG. 12 is a plot of vibration transmissibility when the rigidity of the first propagation path 10 is varied 0.5 to 2.0 times. FIG. 13 is a plot of vibration transmissibility when the mass is varied 0.5 to 2.0 times while keeping the natural frequency of the second propagation path 10 the same. That is, the result of changing the excitation force distribution ratio by the rigidity of the first propagation path 10 or the mass of the second propagation path 11 is shown. In addition, in order to make it easy to understand the change in the frequency of the minimum peak value of the vibration transmissibility, FIGS. 12 and 13 both show the results of setting the attenuation of the first and second propagation paths 10 and 11 to 0 (zero). Is shown.

  From FIG. 12, it can be seen that when the rigidity of the first propagation path 10 is reduced, the frequency at which the vibration transmissibility is minimized is increased, and when the rigidity is increased, the frequency at which the vibration transmissibility is minimized is decreased. This is a result of an increase in the distribution ratio of the excitation force as the rigidity increases. This result indicates that the distribution ratio of the excitation force in the non-vibration-proof area described in the prior application specification by the present applicant increases. (See FIG. 8 of Patent Document 4).

  From FIG. 13, it can be seen that when the mass of the second propagation path 11 is reduced, the frequency at which the vibration transmissibility is minimized is decreased, and when the mass is increased, the frequency at which the vibration transmissibility is minimized is increased.

  As described above, it can be seen from FIGS. 12 and 13 that the frequency at which the vibration transmissibility is minimized can be freely manipulated by changing the rigidity of the first propagation path 10 and the mass of the second propagation path 11. .

  In the prior application according to the present application, that is, in Patent Document 4 described above, the frequency at which the vibration transmissibility is minimized is determined by the excitation force sharing ratio. Assuming that the floor acts on the floor, even if the excitation force sharing ratio is set to 50% for each of the vibration-proof area and the non-vibration-proof area, the same vibration force can be applied for the intended use. It was difficult and there was a possibility that the vibration reduction effect as set could not be obtained.

  On the other hand, the vibration isolation method for a structure floor according to the present invention operates the vibration distribution ratio within the vibration isolation mechanism without being influenced by variations in the vibration force caused by the uneven number of people. Therefore, there is an effect that the vibration reduction effect as set can be obtained.

  In addition, by manipulating the damping parameters described above, it is possible to adjust the peak, minimum value, sharpness, and frequency of vibration transmissibility. On the other hand, an optimal combination can be set flexibly.

  FIG. 14 shows a vibration isolation method for a structure floor according to the second embodiment. The second embodiment is mainly different from the first embodiment in that the mass body 13 is also installed in the first propagation path 10. That is, in the vibration isolating method according to the second embodiment, the first propagation path 10 is a propagation path by the vibration isolating materials 2 and 2 with the mass body 13 sandwiched between the intermediate portions, and the second propagation path 11 has the second propagation path 11. It is not matched with any natural frequency (the invention according to claim 2).

  FIG. 15 is a graph illustrating the frequency characteristics with respect to the vibration reduction rate for the vibration isolation technique according to the second embodiment. A symbol X in the figure indicates the frequency characteristic according to the first embodiment, and a symbol Y indicates the frequency characteristic according to the second embodiment.

  From FIG. 15, it can be seen that if the mass body 13 is also installed in the first propagation path 10, a further vibration reduction effect can be exhibited in the high frequency region as compared with the first embodiment in which the mass body 13 is not installed. In other words, it is effective when used for applications that require vibration reduction even at high frequencies other than a low frequency of several Hz. Specifically, in aerobics studio floors, in addition to vibration frequencies associated with human movements of 2 to 3 Hz, floor impact sounds to the lower floor may be particularly problematic in the 63 Hz and 125 Hz octave bands. Therefore, vibration reduction at a high frequency is required, and as shown in FIG. 14, it is possible to obtain a high vibration reduction effect at a high frequency by using a three-mass system.

  The invention according to claim 2 is not limited to a three-mass system, but by further dividing the mass provided in the first propagation path 10 in series and parallel, further increasing the mass points in the vibration model, This includes actions to obtain a high vibration reduction effect.

  Regarding the vibration transmissibility obtained by dividing the transmission force to the underfloor structure according to Example 1 and Example 2 by the excitation force, as described above, the natural frequency and the damping constant related to the first and second propagation paths, and By tuning the number and excitation force distribution ratio in any combination, various needs for the maximum and minimum values of the vibration transmissibility and the shape of the transmissibility curve (number of peaks and valleys, values, slope, etc.) Can be designed (invention of claim 3), and robustness can also be improved.

  The embodiments have been described with reference to the drawings. However, the present invention is not limited to the illustrated embodiments, and design modifications and application variations that are usually made by those skilled in the art are within the scope of the technical idea of the invention. Note that it includes the range.

It is the perspective view which showed Example 1 of the vibration proofing method of the structure floor concerning the invention described in Claim 1. FIG. A is a graph showing the frequency characteristics with respect to the vibration transmissibility according to the prior art (Patent Document 5), and B is a vibration transmission when two second propagation paths according to the first embodiment are provided. C is a graph showing the frequency characteristics with respect to the vibration transmissibility when four second propagation paths according to Example 1 are provided. The vibration model corresponding to Example 1 is shown. The vibration model is shown when four second propagation paths are provided. It is a graph showing the frequency characteristic with respect to a vibration transmissibility about the fluctuation | variation of attenuation | damping. It is a graph showing the frequency characteristic with respect to a vibration transmissibility about the fluctuation | variation of attenuation | damping. It is the graph showing the frequency characteristic with respect to the vibration transmissibility when attenuation | damping is changed 0.5 time about the direction which set the natural frequency high. It is the graph showing the frequency characteristic with respect to the vibration transmissibility when attenuation | damping is changed 0.5 time about the direction which set the natural frequency high. It is the graph which plotted the vibration transmissibility at the time of changing attenuation of the 1st and 2nd propagation path to 0.5 to 2.0 times. It is the graph which plotted the vibration transmissibility at the time of changing attenuation of only the 2nd propagation path to 0.5 to 2.0 times. The vibration transmissibility is shown when the attenuation of the first propagation path is varied 0.5 to 2.0 times. It is the graph which plotted the vibration transmissibility at the time of changing the rigidity of the 1st propagation path to 0.5 to 2.0 times. It is the graph which plotted the vibration transmissibility at the time of changing mass 0.5 to 2.0 times, keeping the natural frequency of a 2nd propagation path the same. The vibration model corresponding to Example 2 is shown. It is a graph showing the frequency characteristic with respect to a vibration reduction rate about the vibration proof technique which concerns on Example 2. FIG.

Explanation of symbols

1 Floor 2 Anti-vibration material (coil spring)
3 Mass body 4 Anti-vibration material (coil spring)
5 Underfloor Structure 6 Fixing Member 7 Support Member 10 First Propagation Path 11 Second Propagation Path 13 Mass Body

Claims (2)

A vibration reducing device that is provided on the upper surface of a lower structure such as a floor slab or foundation and that supports the upper structure such as a floor structure or equipment on which an excitation force acts,
The vibration reducing device includes a mass body smaller than the mass of the upper structure and the lower structure, a vibration isolating material that elastically supports the upper and lower structures by sandwiching the mass body in an intermediate portion, and the mass body. A vibration reducing device comprising a dynamic vibration absorber.   The vibration reducing device according to claim 1, wherein the dynamic vibration absorber provided on the mass body includes a plurality of dynamic vibration absorbers having different natural frequencies.

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