Bed structure

Abstract

To provide a floor structure that can improve performance against heavy floor impact sound. [Solution] The floor structure 1,101,201 comprises a floor structural member 10, a floor material 20, a first elastic body 30 disposed on the upper surface of the floor structural member 10 and supporting the lower surface of the floor material 20, and dynamic vibration absorbers 40,140,240 disposed between the floor structural member 10 and the floor material 20 to suppress vibrations of at least the floor material 20 in the vertical direction. The dynamic vibration absorbers 40,140,240 comprise a mass 41 disposed to be movable in the vertical direction relative to the floor structural member 10 and the floor material 20, a second elastic body 42,242 disposed on the upper surface of the floor structural member 10 and supporting the mass 41, and vibration damping materials 43,143,243 disposed sandwiched between the floor material 20 and the mass 41, in contact with the lower surface of the floor material 20 and the upper surface of the mass 41, and disposed so as not to separate from the lower surface of the floor material 20 and the upper surface of the mass 41 when the floor material 20 is vibrating.

Description

[Technical Field]

[0001] This invention relates to a floor structure. [Background technology]

[0002] In recent years, reducing the transmission of everyday noises from upper floors to lower floors has become increasingly important in wooden buildings. In particular, measures against heavy floor impact sound (JIS A 1418-2:2019, JIS A 1419-2:2000) are crucial among the everyday noises transmitted to lower floors. Heavy floor impact sound is a dull, low-pitched sound that is transmitted to the floor below, such as a child jumping or a chair being lowered. However, in wooden buildings, it is not as easy to implement measures against heavy floor impact sound as in reinforced concrete or steel-frame buildings.

[0003] One effective measure against heavy floor impact noise is to increase the mass of the floor. However, in wooden buildings, it is not easy to support a floor with columns and beams if its mass is increased. Increasing the number of columns and beams makes it possible to support a floor with increased mass. However, increasing the number of columns and beams increases construction costs. Furthermore, an increase in building mass necessitates ground improvement work in soft ground, which also increases construction costs. Therefore, there is a need to implement measures against heavy floor impact noise while suppressing the increase in floor mass.

[0004] Patent Document 1 discloses that a rigid plate and a pre-compressed damping member are arranged on the underside of the flooring material. When an impact force is applied to the flooring material, the rigid plate does not follow the vibration of the flooring material but remains in a fixed position. The damping member sandwiched between the rigid plate and the flooring material dampens the vibration of the flooring material.

[0005] Patent documents 2 and 3 disclose the placement of a dynamic vibration absorber between the floor structural member (lower floor member) and the flooring material (upper floor member). The dynamic vibration absorber disclosed in patent documents 2 and 3 includes an elastic body that supports the flooring material relative to the floor structural member, and a mass (vibration-damping mass) supported by the elastic body. Therefore, when an impact force is applied to the flooring material, the vibration is transmitted to the mass via the elastic body, damping the vibrations of the flooring material and the floor structural member. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2018-090976 [Patent Document 2] Patent No. 7291490 [Patent Document 3] Patent No. 7364461 [Overview of the project] [Problems that the invention aims to solve]

[0007] In wooden buildings, there is a growing need to take measures against heavy floor impact noise. As disclosed in Patent Document 1, the method of sandwiching a damping member between the floor material and a rigid plate is insufficient. There is also room for improvement in the measures using dynamic vibration absorbers disclosed in Patent Documents 2 and 3.

[0008] When children repeatedly jump on the flooring, impact forces are repeatedly applied to the flooring material. Therefore, even when the flooring material is repeatedly subjected to impact forces, it is necessary to dampen the vibrations caused by these impact forces.

[0009] This invention was made in view of the above background, and aims to provide a floor structure that can improve performance against heavy floor impact sound. [Means for solving the problem]

[0010] One aspect of the present invention is a floor structural material, A flooring material arranged with a gap between it and the upper surface of the aforementioned floor structural material, A first elastic body is positioned on the upper surface of the floor structural material and supports the lower surface of the floor material, The system includes a dynamic vibration absorber positioned between the floor structural material and the floor material, which suppresses vibrations of the floor material in at least the vertical direction, The aforementioned dynamic vibration absorber is The floor structural material and a mass arranged to be movable in the vertical direction relative to the floor material, A second elastic body is positioned on the upper surface of the floor structural material and supports the mass, The floor structure includes a vibration damping material that is positioned between the flooring material and the mass, in contact with the lower surface of the flooring material and the upper surface of the mass, and positioned so as not to move away from the lower surface of the flooring material and the upper surface of the mass when the flooring material is vibrating. [Effects of the Invention]

[0011] According to the floor structure, the dynamic vibration absorber includes a mass, a second elastic body, and a vibration damping material. The vibration damping material is positioned in contact with the underside of the floor material and the top surface of the mass. Furthermore, the vibration damping material is positioned so that it does not separate from the underside of the floor material and the top surface of the mass when the floor material is vibrating. Therefore, when an impact force is applied to the floor material, the vibration of the floor material is transmitted to the mass via the vibration damping material.

[0012] The mass is supported by a second elastic body. Therefore, the mass functions as a vibration-damping mass in the dynamic vibration absorber. In other words, the vibration of the mass can dampen the vibrations of the floor material and floor structural material.

[0013] Furthermore, the vibration damping material does not separate from the underside of the flooring material. Therefore, when an impact force is applied to the flooring material, the vibration damping material can always dampen the vibration of the flooring material while the flooring material is vibrating. In other words, the vibration damping material can dampen the vibration of the flooring material itself and also dampen the vibration transmitted to the flooring structure.

[0014] Furthermore, the vibration damping material does not separate from the underside of the flooring material. Therefore, while the flooring material is vibrating, the vibrations of the flooring material are always transmitted to the mass via the vibration damping material. In other words, when an impact force is applied to the flooring material, after the first wave of the impact force is transmitted to the mass, the vibrations of the second wave and subsequent waves are also transmitted to the mass. Therefore, not only the vibration of the first wave but also the vibrations of the second wave and subsequent waves can be attenuated by transmitting them to the mass. Also, when an impact force is repeatedly applied to the flooring material, not only the initial impact force but also the additional impact force is transmitted to the mass via the vibration damping material. Therefore, even when an additional impact force is applied, the vibrations of the flooring material can be attenuated by transmitting them to the mass.

[0015] Based on the above, it is possible to provide a floor structure that can improve performance against heavy floor impact sound. [Brief explanation of the drawing]

[0016] [Figure 1] This is a plan view of the floor structure in Embodiment 1. [Figure 2] This is a cross-sectional view of the floor structure in Embodiment 1, and is a cross-sectional view taken along line II-II in Figure 1. [Figure 3] This is a floor structure model in Embodiment 1. [Figure 4] This figure shows the floor structure in Embodiment 1 immediately after the impact force of the heavy floor impact evaluation test has been applied. [Figure 5] This diagram shows the floor structure after an impact force has been applied. [Figure 6] This is a cross-sectional view of the floor structure in Embodiment 2. [Figure 7] This is a plan view of the floor structure in Embodiment 3. [Figure 8] This is a cross-sectional view of the floor structure in Embodiment 3, and is the cross-sectional view taken along line VIII-VIII in Figure 7. [Modes for carrying out the invention]

[0017] (Embodiment 1) 1. Overview of the floor structure This floor structure is for wooden buildings. It is particularly applicable to the floor structure of upper floors in wooden buildings. A wooden building is defined as a building in which at least the structural members of the floor are made of wood. That is, the term "wooden building" is used in contrast to steel-frame buildings, concrete buildings, and steel-frame unit buildings. However, this floor structure can also be applied to other types of buildings besides wooden buildings.

[0018] Here, wooden buildings include structures with timber frame construction, two-by-four construction, and combinations of timber frame construction and wall panels. In other words, in wooden buildings, in addition to the floor, structural members such as columns, beams, and wall panels are mainly made of wood. However, the floor structure only needs to be made primarily of wood, and is applicable even if the structural members of the columns, beams, and wall panels are not made of wood.

[0019] Furthermore, the floor structure is primarily designed to reduce everyday noises transmitted from the upper floor to the lower floor. In particular, it aims to reduce heavy floor impact noise (JIS A 1418-2:2019, JIS A 1419-2:2000) transmitted to the lower floor. Heavy floor impact noise is a dull, low-pitched sound that is transmitted to the floor below, such as a loud thud or bang when a child jumps or a chair is lowered.

[0020] JIS A 1418-2:2019 specifies the measurement method for the sound insulation performance of floor impact noise in buildings. Tire impact sources and rubber ball impact sources are listed as standard weight impact sources.

[0021] JIS A 1419-2:2000 specifies the evaluation of the impact sound insulation performance of floors in buildings using grade curves. For a standard weight impact source, measured values ​​are plotted in octave bands with center frequencies of 63Hz, 125Hz, 250Hz, and 500Hz. When these values ​​fall below a certain reference curve in all frequency bands, the sound insulation grade is represented by the numerical value assigned to that smallest reference curve.

[0022] Generally, in floor impact sound insulation performance when impact force is applied from a standard weight impact source, octave bands with a center frequency of 63 Hz or 125 Hz affect the rating. The octave band with a center frequency of 63 Hz includes 44.5 to 89.1 Hz. The octave band with a center frequency of 125 Hz includes 88.4 to 176.8 Hz.

[0023] Therefore, in floor structures, it is important to reduce the octave band with a center frequency of 63Hz or 125Hz as a measure against heavy floor impact sound. However, in wooden buildings, the structural members are mainly made of wood, making them lighter than steel and concrete. In particular, there is a demand for further weight reduction in wooden buildings. The floor structure aims to effectively provide sound insulation in a floor structure made of relatively lightweight wood.

[0024] Furthermore, the floor structure provides sound insulation by elastically supporting the flooring material against the floor structural material. The floor structure also incorporates a configuration for placing dynamic vibration absorbers in the underfloor space. In particular, wooden buildings have a narrower underfloor space between the floor structural material and the flooring material compared to other structures. Therefore, the following floor structure employs a configuration that allows for the placement of dynamic vibration absorbers in a narrow underfloor space. However, the floor structure described below can also be applied to buildings other than wooden buildings that have a sufficiently large underfloor space.

[0025] Furthermore, as mentioned above, octave bands with a center frequency of 63Hz or 125Hz affect the grade. However, the frequencies of sound produced in actual floor structures include bands other than those mentioned above. Therefore, it is important that the floor structure exhibits a reduction effect not only on 63Hz or 125Hz but also on the surrounding frequency bands. The floor structure described below is configured to exhibit a reduction effect on the surrounding frequency bands as well as 63Hz or 125Hz.

[0026] 2. Details of Floor Structure 1 The floor structure 1 will be described with reference to Figures 1 and 2. As shown in Figures 1 and 2, the floor structure 1 comprises a floor structural material 10, a floor material 20, a plurality of first elastic bodies 30, and one or more dynamic vibration absorbers 40.

[0027] The floor structural material 10 is a subfloor material and constitutes one of the structural members of the floor. The floor structural material 10 is made of wood, at least in part. The floor structural material 10 is made of structural plywood, for example. The floor structural material 10 is fixed to the upper surface of columns or beams (including joists), which are not shown. Columns or beams are also mainly made of wood.

[0028] The flooring material 20 is arranged with a gap 50 between it and the upper surface of the floor structural material 10. The flooring material 20 may have a single-layer structure or a multi-layer structure. If the flooring material 20 has a single-layer structure, for example, at least a portion of it is made of wood.

[0029] If the flooring material 20 has a multi-layer structure, it comprises, for example, a base material placed in the lower layer and a surface material placed on the upper surface of the base material. For the base material, for example, wood, autoclaved lightweight concrete (ALC) panels (JIS A 5416), gypsum board, etc. When wood is used as the base material, the base material is formed from, for example, particleboard or plywood.

[0030] Furthermore, a vibration-damping substrate can also be used as the base material. The base material used as a vibration-damping substrate comprises a lower plywood, an upper plywood, and a damping sheet sandwiched between the lower and upper plywood. The base material used as a vibration-damping substrate can primarily target vibration damping in the high-frequency range of everyday noises. The surface layer material is fixed to the upper surface of the base material. The surface layer material can be made of, for example, wood or a cushioning material.

[0031] The first elastic body 30 is positioned on the upper surface of the floor structural material 10 and elastically supports the lower surface of the floor material 20. In other words, the first elastic body 30 is positioned in the gap 50, extending along its entire length in the vertical direction. Therefore, the first elastic body 30 functions as a leg that supports the floor material 20. The first elastic body 30 is mainly made of rubber or elastomer. For example, the first elastic body 30 can be made of natural rubber, synthetic rubber, thermoplastic elastomer, etc. The first elastic body 30 can target vibration isolation over a wide range of frequencies in the frequency band of everyday noise, from low frequencies to high frequencies. In addition to rubber or elastomer, the first elastic body 30 may also include an insert member or a filler.

[0032] The first elastic body 30 is fixed, for example, to the lower surface of the flooring material 20, but not to the upper surface of the floor structural material 10. Furthermore, the first elastic body 30 is formed in the shape of an inverted truncated cone or an inverted truncated pyramidal pyramid, with the lower part having a smaller diameter. However, the first elastic body 30 may also be formed in the shape of a cylinder or a prism.

[0033] The dynamic vibration absorber 40 is positioned in the gap 50 between the floor structural material 10 and the floor material 20. The dynamic vibration absorber 40 suppresses vibrations of the floor material 20 in at least the vertical direction. The dynamic vibration absorber 40 is positioned, for example, inside a region surrounded by a plurality of first elastic bodies 30. The relative positions and number ratios of the first elastic bodies 30 and the dynamic vibration absorber 40 can be changed as appropriate.

[0034] The dynamic vibration absorber 40 comprises a mass 41, a second elastic body 42, and a vibration damping material 43. The dynamic vibration absorber 40 can target vibration damping in the low-frequency range of everyday noises as a countermeasure against heavy floor impact noise.

[0035] Mass 41 is a vibration-damping mass. Mass 41 is made of, for example, metal. Mass 41 is formed in a flat plate shape. For example, Mass 41 is formed in a rectangular shape. However, Mass 41 may be formed in any shape other than rectangular, such as circular or other angular shapes. The thickness of Mass 41 is less than the height of the gap 50 between the floor structural material 10 and the floor material 20. Mass 41 is arranged to be movable in the vertical direction relative to the floor structural material 10 and the floor material 20. The outer edge of Mass 41 is also positioned at a distance from the plurality of first elastic bodies 30.

[0036] The second elastic body 42 is positioned on the upper surface of the floor structural material 10. That is, the lower end of the second elastic body 42 is in contact with the upper surface of the floor structural material 10. The second elastic body 42 also supports the mass 41. In Embodiment 1, the second elastic body 42 is positioned between the upper surface of the floor structural material 10 and the lower surface of the mass 41. In the initial state when the floor material 20 is not vibrating, the second elastic body 42 is slightly pre-compressed. The second elastic body 42 is configured to bias the mass 41 upward. Specifically, four second elastic bodies 42 are positioned at the four corners of the mass 41. However, the position and number of second elastic bodies 42 supporting a single mass 41 can be changed as appropriate.

[0037] The second elastic body 42 can be made of a spring member, rubber, elastomer, or the like. The spring member includes a coil spring and a leaf spring. The spring member is made of, for example, spring steel. In Embodiment 1, a coil spring is used for the second elastic body 42. The coil spring is formed in a conical or cylindrical shape. In Embodiment 1, a coil spring formed in a conical shape is used for the second elastic body 42. The second elastic body 42 is positioned so that its upper end has a smaller diameter. That is, the larger diameter side of the second elastic body 42 contacts the upper surface of the floor structural material 10, and the smaller diameter side contacts the lower surface of the mass 41.

[0038] The second elastic body 42 is configured such that its storage spring constant is small when the amount of compression is small and large when the amount of compression is large. In other words, the second elastic body 42 is initially soft and becomes harder as the amount of compression increases. The above properties can be achieved by using a coil spring formed in a conical shape for the second elastic body 42. Note that the above properties can also be achieved when the second elastic body 42 is made of rubber, elastomer, or leaf spring.

[0039] The vibration damping material 43 is formed in a sheet shape and is positioned sandwiched between the floor material 20 and the mass 41. In the initial state when the floor material 20 is not vibrating, the vibration damping material 43 is positioned in contact with the lower surface of the floor material 20 and the upper surface of the mass 41. In Embodiment 1, the entire upper surface of the vibration damping material 43 is bonded to the lower surface of the floor material 20. Also, the entire lower surface of the vibration damping material 43 is bonded to the upper surface of the mass 41. One vibration damping material 43 may be placed for each mass 41, or multiple vibration damping materials 43 may be placed for each mass 41.

[0040] Furthermore, when the floor material 20 is vibrating, the vibration damping material 43 is positioned so as not to separate from the underside of the floor material 20 and the upper side of the mass 41. In other words, even when the floor material 20 is vibrating, the vibration damping material 43 maintains its adherence to the floor material 20 and the mass 41.

[0041] The vibration damping material 43 is formed from, for example, an adhesive material. The vibration damping material 43 is formed from, for example, a styrene elastomer, butyl rubber, or rubber asphalt. Because the vibration damping material 43 has adhesive properties, it can maintain its adherence to the floor material 20 and the mass 41 even when the floor material 20 is vibrating.

[0042] Furthermore, in the initial state when the floor material 20 is not vibrating, the vibration damping material 43 is positioned compressed across its entire surface between the floor material 20 and the mass 41. This also allows the vibration damping material 43 to maintain its adhesion to the floor material 20 and the mass 41 even when the floor material 20 is vibrating.

[0043] The vibration damping material 43 may be formed from a material that does not have adhesive properties. In this case, an adhesive may be placed on the surface of the vibration damping material 43. That is, the adhesive will bond the vibration damping material 43 to the floor material 20 and to the mass 41. Alternatively, the configuration may be made without an adhesive. In this case, because the vibration damping material 43 is pre-compressed in its initial state, the vibration damping material 43 can maintain contact with the floor material 20 and the mass 41 when the floor material 20 is vibrating.

[0044] 3. Storage spring constant of the first elastic body 30 The spring constant of the first elastic body 30 is adjusted according to the mass of the flooring material 20 and the frequency of the vibration isolation target. The spring-mass structure formed by the flooring material 20 and the first elastic body 30 exhibits vibration isolation effects at frequencies of √2 times or more the resonant frequency of the spring-mass structure.

[0045] As mentioned above, the octave band with a center frequency of 63 Hz includes 44.5 to 89.1 Hz. The octave band with a center frequency of 125 Hz includes 88.4 to 176.8 Hz. When the vibration isolation target frequency is 44.5 Hz, the resonant frequency of the spring-mass structure should be 31.5 Hz or less. When the vibration isolation target frequency is 176.8 Hz, the resonant frequency of the spring-mass structure should be 125.0 Hz or less. Therefore, when the vibration isolation target frequency is 44.5 Hz, it is best to set the upper limit of the resonant frequency of the spring-mass structure to 31.5 Hz or less. When the vibration isolation target frequency is 176.8 Hz, it is best to set the upper limit of the resonant frequency of the spring-mass structure to 125.0 Hz or less.

[0046] For example, the mass of flooring material 20 per unit area is 20 kg / m². 2The storage spring constant of the first elastic body 30 is set as follows: When the vibration isolation target frequency is 44.5 Hz, the storage spring constant of the first elastic body 30 is 213 N / mm or less. When the vibration isolation target frequency is 176.8 Hz, the storage spring constant of the first elastic body 30 is 3369 N / mm or less. Here, the spring constant of the first elastic body 30 is calculated based on the number of first elastic bodies 30 per unit area, which is 3.66 units / m 2 Therefore, the storage spring constant of the first elastic body 30 is set according to the number of first elastic bodies 30 per unit area.

[0047] Furthermore, the mass per unit area of ​​the flooring material 20 is, for example, 100 kg / m². 2 The storage spring constant of the first elastic body 30 is set as follows: When the vibration isolation target frequency is 44.5 Hz, the storage spring constant of the first elastic body 30 is 1067 N / mm or less. When the vibration isolation target frequency is 176.8 Hz, the storage spring constant of the first elastic body 30 is 16844 N / mm or less.

[0048] Furthermore, the first elastic body 30 has a lower limit set for its storage spring constant from the perspective of foot comfort. In other words, the resonant frequency of the spring-mass structure should be 10 Hz or higher. For example, the mass per unit area of ​​the flooring material 20 is 20 kg / m². 2 The storage spring constant of the first elastic body 30 shall be 22 N / mm or more. The mass per unit area of ​​the flooring material 20 shall be 100 kg / m 2 The storage spring constant of the first elastic body 30 shall be 108 N / mm or more.

[0049] Based on the above, the mass per unit area of ​​flooring material 20 is 20 kg / m². 2 The lower limit of the storage spring constant of the first elastic body 30 should be set to 22 N / mm or higher. Furthermore, the mass per unit area of ​​the flooring material 20 should be 20 kg / m². 2 The upper limit of the storage spring constant of the first elastic body 30 should be set according to the vibration isolation target frequency. For example, the upper limit of the storage spring constant of the first elastic body 30 should be set to 213 N / mm or less.

[0050] The mass per unit area of the flooring material 20 is 100 kg / m 2 For this, the lower limit value of the storage spring constant of the first elastic body 30 may be set to 108 N / mm or more. And when the mass per unit area of the flooring material 20 is 100 kg / m 2 For this, the upper limit value of the storage spring constant of the first elastic body 30 may be set according to the vibration isolation target frequency. For example, the upper limit value of the storage spring constant of the first elastic body 30 may be set to 1067 N / mm or less.

[0051] In addition, when an impact force of about 4200 N and about 50 Hz is applied to the flooring material 20 by a tire impact source, in order for the first elastic body 30 to exhibit vibration isolation performance, the resonance frequency of the spring-mass structure composed of the flooring material 20 and the first elastic body 30 may be set to about 20 Hz.

[0052] 4. Characteristics of the dynamic vibration absorber 40 The characteristics of the dynamic vibration absorber 40 will be described with reference to FIG. 3. In particular, the characteristics of the second elastic body 42 and the vibration damping material 43 that constitute the dynamic vibration absorber 40 will be described.

[0053] The characteristics of the second elastic body 42 are represented by the absolute spring constant |k a * |, the storage spring constant k a 1, the loss spring constant k a 2, the damping coefficient c a , the loss factor tanδ a . ω a is the angular frequency. k a 1 = |k a * |cosδ a k a 2 = |k a * |sinδ a c a = k a 2 / ω a tanδ a = k a 2 / k a 1

[0054] The characteristics of the vibration damping material 43 are as follows: absolute spring constant |k b * |, storage spring constant k b 1. Loss spring constant k b 2. Damping coefficient c b , loss coefficient tanδ b It is represented by ω. b This is the angular frequency. k b 1 = |k a * |cosδ b k b 2 = |k a * |sinδ b c b =k b 2 / ω b tanδ b =k b 2 / k b 1

[0055] The second elastic body 42 and the damping material 43 have the following relationship: That is, the absolute spring constant of the damping material 43 is |k b * | is the absolute spring constant of the second elastic body 42 |k a * | is greater than |. Storage spring constant k of damping material 43 b 1 is the storage spring constant k of the second elastic body 42. a Greater than 1. The loss spring constant k of the damping material 43. b 2 is the loss spring constant k of the second elastic body 42. a It is greater than 2. The loss coefficient tanδ of the damping material 43. b The loss coefficient tanδ of the second elastic body 42 is a It is greater than [the specified value]. However, it is not necessary to satisfy all four of these relationships; at least one relationship must be satisfied.

[0056] |k b * |>|k a * | k b 1>k a 1 k b2>k a 2 tanδ b >tanδ a

[0057] Furthermore, in the second elastic body 42, the storage spring constant k a 1 and loss spring constant k a The smaller 2 is possible. Also, in the vibration damping material 43, the loss spring constant k b The larger the value of 2, the better.

[0058] An example of the characteristics of the dynamic vibration absorber 40 will be described. The eigenvalues ​​of the dynamic vibration absorber 40 will be, for example, 44.5 to 89.1 Hz. The mass ratio of the mass 41 to the mass of the floor material 20 will be 10 to 30%. Also, the loss coefficient tanδ of the vibration damping material 43 will be described. b Let it be 1.6.

[0059] Assume the mass of the flooring material 20 is 20 kg. In this case, if the mass ratio of the mass 41 to the mass of the flooring material 20 is 10%, the storage spring constant per second elastic body 42 is 39 to 157 N / mm. If the mass ratio of the mass 41 to the mass of the flooring material 20 is 30%, the storage spring constant per second elastic body 42 is 117 to 470 N / mm.

[0060] Assume the mass of the flooring material 20 is 100 kg. In this case, if the mass ratio of the mass 41 to the mass of the flooring material 20 is 10%, the storage spring constant per second elastic body 42 is 195 to 784 N / mm. If the mass ratio of the mass 41 to the mass of the flooring material 20 is 30%, the storage spring constant per second elastic body 42 is 586 to 2351 N / mm.

[0061] 5. Operation of the dynamic vibration absorber 40 The operation of the dynamic vibration absorber 40 will be explained with reference to Figures 4 and 5. As shown in Figure 4, the tire impact source applies an impact force of approximately 4200 N and approximately 50 Hz to the floor material 20. The resonant frequency of the spring-mass structure composed of the floor material 20 and the first elastic body 30 is set to approximately 20 Hz. Therefore, the first elastic body 30 exhibits a vibration damping effect against this impact force.

[0062] Immediately after an impact force is applied, the floor material 20 flexes downward. Here, the vibration damping material 43 is positioned in contact with the lower surface of the floor material 20 and the upper surface of the mass 41. Therefore, the vibration damping material 43 absorbs the impact force in proportion to the amount of shear deformation of the floor material 20.

[0063] When an impact force is applied to the flooring material 20, the impact force is transmitted to the mass 41 via the vibration damping material 43. The mass 41 is supported by the floor structural material 10 by the second elastic body 42. In other words, the mass 41, the second elastic body 42, and the vibration damping material 43 constitute the dynamic vibration absorber 40. The mass 41 functions as the vibration damping mass of the dynamic vibration absorber 40. By vibrating, the vibrations of the flooring material 20 and the floor structural material 10 can be attenuated.

[0064] The second elastic body 42 and the vibration damping material 43 can function as described above if their characteristics have one of the following relationships. |k b * |>|k a * | k b 1>k a 1 k b 2>k a 2 tanδ b >tanδ a

[0065] Furthermore, the second elastic body 42 has a storage spring constant k when the amount of compression is small. a When 1 is small and the compression amount is large, the storage spring constant k a The configuration is such that 1 is large. Therefore, when an impact force is applied, the second elastic body 42 first deflects a portion of the impact force and then acts to firmly absorb the impact force. As a result, the impact force transmitted to the floor structural material 10 via the second elastic body 42 is reduced.

[0066] Thus, the second elastic body 42 functions as a spring for the dynamic vibration absorber 40 and also exhibits an impact force absorption effect in the initial stages when an impact force is applied. In particular, when a heavy floor impact force is applied to the flooring material 20, the initial impact force is large, so exhibiting an impact force absorption effect in the initial stages is useful.

[0067] Furthermore, the vibration damping material 43 does not move away from the underside of the floor material 20. Specifically, as shown in Figure 5, when the floor material 20 is vibrating, the vibration damping material 43 does not move away from the underside of the floor material 20. Therefore, when an impact force is applied to the floor material 20, the vibration of the floor material 20 can always be dampened by the vibration damping material 43 while the floor material 20 is vibrating. In other words, the vibration damping material 43 can dampen the vibration of the floor material 20 itself and also dampen the vibration transmitted to the floor structural material 10.

[0068] Furthermore, the vibration damping material 43 does not move away from the underside of the floor material 20. Therefore, while the floor material 20 is vibrating, the vibration of the floor material 20 is always transmitted to the mass 41 via the vibration damping material 43. In other words, when an impact force is applied to the floor material 20, after the first wave of the impact force is transmitted to the mass 41, the vibrations of the second wave and subsequent waves are also transmitted to the mass 41. Therefore, the vibration of the floor material 20 can be attenuated not only by transmitting the vibration of the first wave but also the vibrations of the second wave and subsequent waves to the mass 41.

[0069] Furthermore, when impact forces are repeatedly applied to the flooring material 20, not only the initial impact force but also the additional impact forces are transmitted to the mass via the vibration damping material 43. Therefore, even when additional impact forces are applied, the vibrations of the flooring material 20 can be attenuated by the transmission of vibrations to the mass.

[0070] (Embodiment 2) The floor structure 101 in Embodiment 2 will be described with reference to Figure 6. Note that, among the reference numerals used in Embodiment 2 and later, those that are the same as those used in previously described embodiments represent the same components as those in the previously described embodiments, unless otherwise specified.

[0071] The floor structure 101 differs from the floor structure 1 in Embodiment 1 in that the vibration damping material 43 is different. In the floor structure 101, the vibration damping material 143 constituting the dynamic vibration absorber 140 is formed in a sheet shape. However, the vibration damping material 143 has protrusions 143a on its upper surface. Here, the vibration damping material 143 may have multiple protrusions 143a or it may have only one protrusion 143a. Also, the protrusions 143a are located in the center of the upper surface of the vibration damping material 143. However, the protrusions 143a may be located at the edges of the upper surface of the vibration damping material 143, or at both the center and the edges.

[0072] Furthermore, in the initial state when the floor material 20 is not vibrating, the tip of the projection 143a is in contact with the underside of the floor material 20. Moreover, even when the floor material 20 is vibrating, the tip of the projection 143a is in contact with the underside of the floor material 20. Therefore, even when the floor material 20 is vibrating, the projection 143a of the vibration damping material 143 does not separate from the underside of the floor material 20.

[0073] On the upper surface of the vibration damping material 143, parts other than the protrusion 143a do not come into contact with the lower surface of the flooring material 20. However, depending on the vibration pattern of the flooring material 20, parts other than the protrusion 143a on the upper surface of the vibration damping material 143 may come into contact with the lower surface of the flooring material 20. In other words, it is sufficient that at least a portion of the vibration damping material 143 comes into contact with the lower surface of the flooring material 20.

[0074] Furthermore, in the initial state when the floor material 20 is not vibrating, the vibration damping material 143 is positioned in a compressed state between the floor material 20 and the mass 41 at the portion of the projection 143a. In other words, in the initial state when the floor material 20 is not vibrating, at least a portion of the vibration damping material 143 is positioned in a compressed state between the floor material 20 and the mass 41.

[0075] Embodiment 2 also exhibits substantially the same effects as Embodiment 1. Alternatively, instead of the vibration damping material 143 having a projection 143a, the upper surface of the vibration damping material 143 may be formed into a curved convex shape.

[0076] The lower surface of the vibration damping material 143 is in full contact with the upper surface of the mass 41. However, it is not necessary for the entire lower surface of the vibration damping material 143 to be in contact with the upper surface of the mass 41; it is sufficient for at least a portion of the lower surface of the vibration damping material 143 to be in contact with the upper surface of the mass 41.

[0077] (Embodiment 3) The floor structure 201 in Embodiment 3 will be described with reference to Figures 7 and 8. The floor structure 201 differs from the floor structure 1 in Embodiment 1 in the second elastic body 42 and the vibration damping material 43.

[0078] As shown in Figure 8, in the floor structure 201, the second elastic body 242 constituting the dynamic vibration absorber 240 has a structure similar to the first elastic body 30. The second elastic body 242 is made of rubber or elastomer. The second elastic body 242 is positioned on the upper surface of the floor structure material 10 and supports the lower surface of the floor material 20. Furthermore, the second elastic body 242 supports the mass 41 at an intermediate position in the vertical direction.

[0079] The second elastic body 242 is formed from the same material as the first elastic body 30, for example. However, depending on the following characteristics, the second elastic body 242 may be formed from a different material than the first elastic body 30. Also, the external shape of the second elastic body 242 is formed to be the same as that of the first elastic body 30. That is, the second elastic body 242 is formed to be an inverted frustoconical shape or an inverted frustoconical shape.

[0080] The second elastic body 242 comprises a lower support portion 242a, an upper support portion 242b, and an intermediate portion 242c. The lower support portion 242a is located between the floor structural material 10 and the mass 41, and supports the mass 41 from below relative to the floor structural material 10. The upper support portion 242b is located between the floor material 20 and the mass 41, and supports the mass 41 from above relative to the floor material 20. The intermediate portion 242c is located between the lower support portion 242a and the upper support portion 242b. The upper surface of the lower support portion 242a, the lower surface of the upper support portion 242b, and the outer circumferential surface of the intermediate portion 242c form a slit configured to position the mass 41.

[0081] When viewed from above, the vibration damping member 243 has an outer shape smaller than the outer shape of the mass 41. Other configurations of the vibration damping member 243 are the same as those of the vibration damping member 43 in Embodiment 1.

[0082] The characteristics of the dynamic vibration absorber 240 will be described with reference to FIG. 3. In particular, the characteristics of the second elastic body 242 and the vibration damping member 243 that constitute the dynamic vibration absorber 240 will be described.

[0083] As characteristics of the lower support portion 242a of the second elastic body 242, the absolute spring constant |k c * |, the storage spring constant k c 1, the loss spring constant k c 2, the damping coefficient c c , the loss factor tanδ c are represented by ω c being the angular frequency. k c 1 = |k c * |cosδ c k c 2 = |k c * |sinδ c c c = k c 2 / ω c tanδ c = k c 2 / k c 1

[0084] The second elastic body 242 and the vibration damping member 243 have the following relationship. That is, the absolute spring constant |k b * | of the vibration damping member 243 is larger than the absolute spring constant |k c * | of the lower support portion 242a of the second elastic body 242. The storage spring constant k b 1 of the vibration damping member 243 is larger than the storage spring constant k c 1 of the lower support portion 242a of the second elastic body 242. The loss spring constant k b 2 of the vibration damping member 243 is the loss spring constant k cIt is greater than 2. The loss coefficient tanδ of the vibration damping material 243. b This is the loss coefficient tanδ of the lower support portion 242a of the second elastic body 242. c It is larger than that.

[0085] |k b * |>|k c * | k b 1>k c 1 k b 2>k c 2 tanδ b >tanδ c

[0086] However, as in Embodiment 1, the characteristics of the lower support portion 242a of the second elastic body 242 and the damping material 243 may be such that they have any one of the above relationships. Furthermore, in the lower support portion 242a of the second elastic body 242, the storage spring constant k c 1 and loss spring constant k c The smaller the value of 2, the better. Embodiment 3 also exhibits the same effects as Embodiment 1. [Explanation of Symbols]

[0087] 1,101,201 Floor structure 10 Floor structural materials 20 Flooring 30 First elastic body 40,140,240 Dynamic vibration absorber 41 squares 42,242 Second elastic body 43,143,243 Damping material 50 gaps 143a protrusion 242a Lower support part 242b Upper support part 242c middle part

Claims

1. Floor structural materials, A flooring material arranged with a gap between it and the upper surface of the aforementioned floor structural material, A first elastic body is positioned on the upper surface of the floor structural material and supports the lower surface of the floor material, The system includes a dynamic vibration absorber positioned between the floor structural material and the floor material, which suppresses vibrations of the floor material in at least the vertical direction, The aforementioned dynamic vibration absorber is The floor structural material and a mass arranged to be movable in the vertical direction relative to the floor material, A second elastic body is positioned on the upper surface of the floor structural material and supports the mass, A floor structure comprising: a vibration damping material positioned between the floor material and the mass, in contact with the lower surface of the floor material and the upper surface of the mass, and positioned so as not to move away from the lower surface of the floor material and the upper surface of the mass when the floor material is vibrating.

2. The floor structure according to claim 1, wherein the vibration damping material is formed in a sheet shape, at least a portion of the upper surface of the vibration damping material is adhered to the lower surface of the floor material, and at least a portion of the lower surface of the vibration damping material is adhered to the upper surface of the mass.

3. The floor structure according to claim 2, wherein the vibration damping material is formed in a sheet shape, the entire upper surface of the vibration damping material is adhered to the lower surface of the floor material, and the entire lower surface of the vibration damping material is adhered to the upper surface of the mass.

4. The floor structure according to claim 1, wherein at least a portion of the vibration damping material is arranged in a compressed state between the floor material and the mass when the floor material is not vibrating in the initial state.

5. The floor structure according to claim 4, wherein the vibration damping material is formed in a sheet shape and is arranged in a compressed state between the floor material and the mass over its entire surface in an initial state in which the floor material is not vibrating.

6. The floor structure according to any one of claims 1 to 5, wherein the second elastic body is disposed between the upper surface of the floor structural material and the lower surface of the mass and is configured to bias the mass upward.

7. The floor structure according to claim 6, wherein the second elastic body is a spring member.

8. The floor structure according to claim 7, wherein the spring member is a cone-shaped coil spring.

9. The floor structure according to claim 6, wherein the second elastic body is configured such that the storage spring constant is small when the amount of compression is small, and the storage spring constant is large when the amount of compression is large.

10. The absolute spring constant of the damping material is greater than the absolute spring constant of the second elastic body. and / or, The floor structure according to claim 6, wherein the loss coefficient of the vibration damping material is greater than the loss coefficient of the second elastic body.

11. The floor structure according to any one of claims 1 to 5, wherein the second elastic body is formed of rubber or elastomer, is placed on the upper surface of the floor structural material, supports the lower surface of the floor material, and supports the mass at an intermediate position in the vertical direction.

12. The floor structure according to claim 11, wherein the second elastic body is formed of the same material as the first elastic body.

13. The second elastic body is A lower support portion located between the floor structural material and the mass, which supports the mass relative to the floor structural material, It comprises an upper support portion located between the flooring material and the mass, which supports the mass relative to the flooring material, The absolute spring constant of the damping material is greater than the absolute spring constant of the lower support portion of the second elastic body. and / or, The floor structure according to claim 11, wherein the loss coefficient of the vibration damping material is greater than the loss coefficient of the lower support portion of the second elastic body.

14. The aforementioned floor structural material is formed of wood in at least part and is supported by columns or beams also made of wood. A floor structure for wooden buildings, according to any one of claims 1 to 5.

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