JPH0245369Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to a composite floor structure that is optimal as a floor structure for a house. The floor structure of detached houses, apartment complexes, etc. is a water-based double floor structure, and most of them are constructed using the joist construction method, in which particle board 12 is laid on wooden or steel joists 10, as shown in Figure 1. However, the floor construction method is also used. With the floor structure of such houses, the most common complaint is that the floor impact noise caused by children jumping on the upper floor is transmitted to the lower floor, and for this reason, various countermeasures have been taken in the past. In the conventional countermeasure, rubber sheet embedding, the rubber sheet itself is relatively hard, and although this hardness is controlled by the shape factor, it is extremely difficult to process. Additionally, since the rubber needs to be vulcanized, the structure has low loss (loss of vibration energy). Another countermeasure is to embed cork sheets, but cork sheets are hard and difficult to process. Also, methods of applying foam as a backing for the finishing material are also adopted, but these are less effective when the impact input is large. In consideration of the above facts, the present invention aims to obtain a composite floor structure that has a high loss level, a low spring constant, and is capable of effectively blocking impact sound over a wide frequency band. The composite floor structure of the present invention has a 25% compression modulus of 100 g/cm ² or less and a foam compressed to 1/2 to 1/10 in the thickness direction, which is sandwiched between plates in layers with a thickness of 2 mm or more. It is designed to absorb impact sound in the frequency range. Embodiments of the present invention will be described below with reference to the drawings. In this embodiment shown in FIG. 2, a particle board 12 (thickness 15 mm) and a compressed form 14 (thickness 5
mm) and plywood 16 (thickness: 9 mm) are laid one after another. The compressed form 14 thus has a sandwich structure sandwiched between the particle board 12 and the plywood 16. Since the veneer plywood 16 is laid on the compression foam 14, the load is dispersed and transmitted to the compression foam 14 due to the rigidity of the veneer plywood 16. The wall thickness of the veneer plywood 16 necessary for dispersing this stress is 3 mm or more. Furthermore, an interior material is laid on the upper side of this plywood 16. On the other hand, a plaster ceiling 18 with a wall thickness of 9 mm is suspended from the joists 10. The compressed foam 14 can be easily manufactured by heating and compressing foamed foam such as polyvinyl chloride, polyethylene foam, soft urethane foam, etc. However, even when compressed, there are foamed voids inside, so the shock absorption properties are poor. In good condition. This compression may be physical compression, but if thermal compression is used, the internal foamed empty cell structure will have a flat shape that is long in the horizontal direction, resulting in a structure that is resistant to fatigue. By compressing in this way, loss inside the foam can be improved. This compressed form 14 can be attached to a conventional plate using an adhesive, and then another plate can be bonded in a factory to form a sandwich structure, and then assembled at the work site. It may also be a structure. Compression form 14
The board material such as the plywood 16 to be bonded to the upper side of the board is not particularly limited, but preferably has a wall thickness of approximately 3 mm or more in terms of rigidity and strength. Panels with a sandwiched foam layer are
It is important to suppress vibration transmission to the particle board 12 when an impact load is applied to the plywood board 16 shown in the figure. This shape can basically be regarded as a model of a vibration system with one degree of freedom, and is made of plywood 16
The ^{form in} _which ^{the vibration of} _is transmitted _to the particle board ₁₂ ^is _|
4π ² f ² _{) 2} +η ²・m ₁・R ₁・4π ² f ^2where , Spring constant of one foam layer f...Frequency η...Loss (loss coefficient) _m1 ...Represented by the mass of the particle board 12. If we describe the calculation results of the response characteristics in this case, the fourth
If the loss is large to some extent and the spring constant is small, particle board 1 will become as shown in Fig. 5.
2 is suppressed, resulting in excellent effects. This effect is generally large in the high frequency range, and the experimental results shown in FIG. 3 also support this characteristic. In general, the spring constant of the compression of the foam is determined by the initial deformation region of the compression characteristics of the foam shown in FIG. 6 (i.e., a
However, the non-compressed form A has a large slope at the time of initial deformation, and therefore exhibits stiff behavior. This indicates that the effect of suppressing the vibration transmissibility is small, as shown by the principle described above. Meanwhile, heat press this foam (200℃ x 3 minutes)
When compressed, the compression characteristics are soft at the beginning and have no inflection point from A to B in the middle, as shown in FIG. When compressed and used in this way, it is initially soft and has a low spring constant, so the noise reduction effect is large, and there is no inflection point, so
A highly durable floor structure can be obtained. It is also clear that it becomes 1/20 harder and its properties are not much different from the uncompressed material of Example A. In addition, when subjected to a static load, in example a, the cells of the foam begin to collapse in an area exceeding 50 g/cm ² (displacement increases, but the load does not), and if used in this area, the foam will undergo permanent deformation. The floor dimensions themselves will change, resulting in serious defects. Next, experimental results using this example will be explained. A model room with an upper and lower floor of 8 tatami mats was manufactured using prefabricated wood materials, and a tapping machine was installed in the center of the upper floor. Figure 3 shows the results of measuring the floor impact sound levels on the lower floor when using various floor structures.

【table】

[Table] In the above table, the foam 25% compression modulus is 25%
The compressive load (g/cm ² ) in strain is shown. Comparative Example 6 had sufficient floor impact sound characteristics, but when a load of 50 kg, equivalent to a bookshelf, was applied to the edge of the panel that had been sandwiched with this foam thickness,
After one week, the amount of displacement at the end reached 30% (3 mm), and it felt too soft when walking, so it was judged that it was unsuitable for a floor structure. From the above results, the compression foam used in the present invention must have a high internal loss and a soft spring constant.If the compression ratio is set to 1/2 or less, the spring constant will be too small, resulting in insufficient strength or foam creep. It can be seen that 2/1 or more is preferable because it becomes a cause. Further, if the compression ratio is 1/10 or more, the internal loss becomes too low, the spring becomes hard, and the effect on floor impact noise becomes small, so a compression ratio of 1/10 or less is preferable. Furthermore, if the foam has a 25% compression modulus of 100 g/cm ² or more, the foam material will be too hard and the loss will be low, so it is found that 100 g/cm ² or less is preferable. Furthermore, as is clear from Figure 3, the compression foam used in this invention has a 25% compression modulus of 50g/cm ²
And even when the compression ratio is 1/2, when the foam thickness is 1 mm (Comparative Example 7), the foam thickness is 2 mm.
The floor impact sound level is higher than in (Example 3). Furthermore, FIG. 7 shows the relationship between the foam thickness and the compressive load amount, and in the initial minute displacement region, the spring characteristics of the foam thickness of 1 mm and the foam thickness of 2 mm are the same. However, when subjected to a large displacement, the spring characteristics change depending on the foam thickness, and a foam with a thickness of 1 mm has a larger spring constant than a foam with a thickness of 2 mm. Therefore, when considering the actual displacement range, the noise reduction effect is extremely small when the foam thickness is 1 mm. Therefore, from the point of view of noise reduction, it is necessary that the foam thickness be 2 mm or more. As explained above, the composite floor structure according to the present invention has a 25% compression modulus of 100 g/cm ² or less and 1/2
Since the foam with a wall thickness of 2 mm or more compressed to ~1/10 is sandwiched between the plates, it reliably reduces the transmission of floor impact sound to the lower floor, and has an excellent effect of absorbing noise levels in a wide frequency band.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views showing a conventional example and an embodiment of the composite floor structure according to the present invention, respectively, and FIG. 3 shows the frequency and floor impact noise reduction effect of the composite floor structure of the present embodiment. A diagram showing the relationship between impact sound levels, Figure 4 is a graph showing the influence of the spring constant on the vibration transmissibility, Figure 5 is a graph showing the effect of a 1-degree-of-freedom vibration system on the vibration transmission rate of loss, and Figure 6 The figure is a graph showing the compression characteristics of the foam, and FIG. 7 is a graph showing the relationship between the foam thickness and the amount of compression load. 10...joist, 12...particle board,
14... Compression foam, 16... Veneer plywood, 1
8...Gypsum ceiling.

Claims (1)

[Scope of utility model registration request] A composite floor structure characterized in that a foam having a 25% compression modulus of 100 g/cm ² or less and compressed to 1/2 to 1/10 in the thickness direction is sandwiched between boards in a layered form with a wall thickness of 2 mm or more.