JP2011246906A - Vibration isolating implement of double floor and double floor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration isolation implement of a double floor and the double floor that can be manufactured at a low cost with a simple structure and that can reduce the transmission of vibration of 50 Hz or so more than the conventional one.SOLUTION: An external member that is formed in a cylindrical shape with an elastic material such as rubber having a hardness higher than that of an internal member is externally fitted to the internal member that has a support surface for supporting a support bolt and is formed in a cylindrical or columnar shape with the elastic material such as rubber.

Description

  The present invention relates to a vibration isolator that is attached to a lower end of a support bolt that supports an upper floor in a double floor in which an upper floor is constructed on a lower floor such as a concrete slab such as a reinforced concrete structure.

  FIG. 7 is a cross-sectional explanatory view of a double floor equipped with a conventional vibration isolator. Conventionally, a double floor in which a plurality of receiving plates 6 (bundle plates or joists) are arranged side by side on a lower floor 8 such as a concrete slab, and an upper floor 9 is pasted thereon is known. The upper floor 9 is usually composed of a lower pasting material 9a such as particle board and a finishing material 9b such as flooring. The receiving plate 6 includes a square-shaped bundle plate, an elongated plate-like joist, etc., and the foot member 1 protruding downward is attached at one place in the center in the case of the bundle plate, and at least two places near both ends in the case of joists. It is done. The foot member is a support bolt 5 having a vibration isolator 10 attached to the lower end, and is screwed to a receiving nut 7 attached to a wooden receiving plate 6. A groove is formed on the upper end surface of the support bolt 5, and the height can be adjusted by rotating the support bolt 5 with a screwdriver or the like from above the lower paste. The vibration isolator 10 is a rubber lump having a single structure, and is attached to the support bolt 5 by fitting the lower end of the support bolt 5 into an inner hole recessed in the upper surface. Such a vibration isolator reduces vibration (sound) from being transmitted from the upper floor to the lower floor or from the lower floor to the upper floor.

  Patent Document 1 listed below discloses a soundproofing performance higher than that of the conventional vibration isolator. This includes a vibration isolator having an upper member, a lower member made of an elastic material such as rubber having a recess having a diameter larger than that of the upper member on the upper surface, and a peripheral wall formed in a generally cylindrical shape so as to be fitted on the lower member. And an outer fitting member having a support film provided in a horizontal direction with an outer peripheral portion attached thereto. The support film comes into contact with the upper surface of the lower member while the outer fitting member is fitted on the lower member, and the upper member is supported on the support film and on the recess. The sound of the upper floor is transmitted to the lower floor via the upper member, the support film, and the lower member, but since the upper member is supported on the support film just like riding on a hammock, the vibration of the upper member is supported by the support film. It is difficult to be absorbed by the vibration and transmitted to the lower member.

JP 2003-328539 A

Sounds transmitted from the upper floor to the lower floor include light impact sounds and heavy impact sounds. Light impact sounds are mainly based on normal life sounds, and heavy impact sounds are caused by special actions such as the sound of a child running around and the sound generated when an object is dropped.
The sound insulation performance of the double floor itself is based on the fact that the floor is constructed on the upper floor against the volume measured on the lower floor by generating noise directly on the upper floor concrete floor (lower floor) with a tamping machine etc. Evaluate how much the sound volume measured on the lower floor is reduced by generating noise, and it is expressed as a “floor impact noise reduction performance grade” based on a certain standard. The light impact sound is represented by “ΔLL value”, and the heavy impact sound is represented by “ΔLH value”.

  In addition to vibration and noise generated on the upper floor, there is vibration transmitted from the outside to the upper floor. Such external vibrations are, for example, vibrations of trains and subways that pass nearby, vibrations generated by construction work in the vicinity, and the like, and low-frequency vibrations around 50 Hz are said to give the most discomfort.

Although the conventional vibration isolator made of a rubber lump having a single structure shown in FIG. 7 is excellent in light impact noise reduction performance, low frequency vibration and heavy impact noise are hardly reduced.
Further, the vibration isolator of Patent Document 1 has a problem that the structure is complicated and the cost is considerably increased.

  The present invention is a vibration isolator that has a simple structure and can be manufactured at a low cost, and is capable of reducing transmission of vibration around 50 Hz, which a resident feels most uncomfortable, as compared with a conventional vibration isolator. It is what.

[Claim 1]
The present invention provides a vibration isolator that is attached to a lower end of a support bolt of a foot member that supports an upper floor of a double floor, has a support surface that supports the support bolt, and is formed into a cylindrical shape or a column shape with an elastic material such as rubber. The outer member is formed in a cylindrical shape with an inner member formed and an elastic material such as rubber, and the outer member has a hardness greater than the hardness of the inner member. It is a double floor anti-vibration device.

Since the vibration isolator is constituted by the inner member and the outer member, when low-frequency vibration from the outside is transmitted to the support bolt, a part of the vibration is transmitted between the inner member and the outer member, and the transmitted vibration is reduced.
In addition, since the outer member having a large hardness is externally fitted to the inner member, the inner member is not easily deformed when a load from the support bolt acts on the inner member. The rubber of the vibration isolator is made of rubber having a hardness of about 65 because the upper floor sinks when deformed by a load from the support bolt. In the present invention, even if a soft member (hardness of 60 or less) that is difficult to transmit low-frequency vibration is used as the inner member, deformation is limited by the outer member that is externally fitted, and sinking is reduced.

[Claim 2]
Moreover, this invention is a vibration isolator of Claim 1 whose hardness of the said inner member is 50-60, and whose hardness of the said outer member is 65-75.

In the present invention, “hardness” is a value measured with a type A durometer in accordance with JIS K 6253.
If the hardness of the inner member is less than 50, the sinking of the upper floor may be increased, which is not preferable. If it is greater than 60, the effect of reducing the transmission of low-frequency vibrations may be reduced. Accordingly, the hardness of the inner member is suitably 50-60.
If the hardness of the outer material is less than 65, the effect of limiting the deformation of the inner member is reduced, and the sinking of the upper floor may be increased. If it exceeds 75, the effect of reducing the transmission of low-frequency vibrations may be reduced. Therefore, the hardness of the outer member is appropriately 65 to 75.

[Claim 3]
Moreover, this invention has a protrusion on the outer peripheral surface of the inner member or the inner peripheral surface of the outer member, and when the outer member is externally fitted to the inner member, the outer peripheral surface of the inner member and the inner periphery of the outer member It is a vibration isolator of Claim 1 or 2 which has a clearance gap between surfaces other than this protrusion.

  The contact area between the inner member and the outer member is reduced by the gap, and transmission of low-frequency vibration can be further reduced.

[Claim 4]
The present invention is the vibration isolator according to claim 3, wherein a plurality of the protrusions are formed in the vertical direction or a plurality of protrusions are formed in the circumferential direction.

  As a specific example of the protrusion, a plurality of protrusions can be formed in the longitudinal direction or the circumferential direction. Moreover, it can also provide not only a linear form but dot shape.

[Claim 5]
Moreover, this invention is the double floor characterized by having supported the upper floor with the foot member which mounted | wore the support bolt lower end with the vibration isolator of Claims 1-4.

  In the double floor of the present invention, the vibration isolator to be attached to the lower end of the support bolt is the vibration isolator of the present invention, and other configurations may be exactly the same as those of a conventionally known double floor.

  Since the vibration isolator of the present invention has a simple structure in which an inner member and an outer member having different hardnesses are fitted together, it can be easily manufactured at low cost. Further, the vibration isolator of the present invention and the double floor using the same are unlikely to transmit low frequency vibrations of around 50 Hz (40 to 60 Hz) from the outside to the upper floor.

It is a longitudinal cross-sectional explanatory drawing of the vibration isolator of an Example. It is a longitudinal cross-sectional explanatory drawing of the vibration isolator of an Example. It is a longitudinal cross-sectional explanatory drawing of the vibration isolator of an Example. It is a cross-sectional explanatory drawing of the vibration isolator of an Example. It is a cross-sectional explanatory drawing of the vibration isolator of an Example. It is explanatory drawing of an inner member. It is a section explanatory view of a double floor. It is explanatory drawing of a vibration test method.

FIG. 1 is a cross-sectional explanatory view of the vibration isolator 2 of the embodiment.
The vibration isolator 2 includes an inner member 3 and an outer member 4 made of synthetic rubber having different hardnesses. The inner member 3 has a hardness of 50 to 60 and has a substantially cylindrical shape. The lower portion of the support bolt 5 is fitted into the inner hole 32, and the flange portion 5a and lower surface of the support bolt are the upper surface 31 of the inner member and the bottom surface 32a of the inner hole. The upper surface 31 and the bottom surface 32a are supporting surfaces that support the supporting bolts.

The external material 4 has a hardness of 65 to 75, and has a bottomed cylindrical shape with the peripheral wall 41 and the bottom plate 42.
The outer member 3 is fitted on the inner member 3 (the inner member 3 is fitted in the outer member 4).

FIG. 2 is a cross-sectional explanatory view of a vibration isolator 2a according to another embodiment.
The vibration isolator 2a also includes an inner member 3 and an outer member 4 made of synthetic rubber having different hardnesses. The inner member 3 has a hardness of 50 to 60 and has a cylindrical shape. The outer material 4 has a hardness of 65 to 75, has a bottomed cylindrical shape by the peripheral wall 41 and the bottom plate 42, and is externally fitted to the inner member 3.

  The lower portion of the support bolt 5 is fitted into the outer member 4, and the bottom surface thereof is supported by contacting the upper surface 31 of the inner member. That is, the upper surface 31 of the inner member is a support surface that supports the support bolt.

FIG. 3 is a cross-sectional explanatory view of a vibration isolator 2b according to another embodiment.
The vibration isolator 2b has substantially the same structure as the vibration isolator 2a, but differs only in that the bottom plate is not formed on the outer member 4. As described above, even when there is no bottom plate of the outer member, there is an effect of reducing transmission of low-frequency vibration. However, it is more effective to form the bottom plate on the outer member as in the above-described embodiment.

As shown in the upper part of FIG. 4, in the vibration isolator 2, 2a, 2b of the above-described embodiment, a plurality of (in this case, eight) protrusions 33 are formed on the outer peripheral surface of the inner member 3 in the vertical direction. When the external member is fitted externally, a gap is formed in a portion other than the protrusion 33 between the outer peripheral surface of the inner member 3 and the inner peripheral surface of the outer member 4 as shown in the lower part of FIG. The gap is appropriately about 2 to 2.5 mm.
Thus, the effect which reduces transmission of a low frequency vibration improves by forming a clearance gap with a protrusion.

  FIG. 5 shows a case where the protrusion 43 is provided on the inner surface of the outer member 4. This case also has the same effect as the case where the protrusion is provided on the inner member.

FIG. 6 shows an example in which a plurality of protrusions 33 (four in this case) are provided on the outer peripheral surface of the inner member 3 along the circumferential direction.
Thus, in the present invention, the protrusion may be any shape as long as a gap is formed between the outer peripheral surface of the inner member and the inner peripheral surface of the outer member.

Comparison of the double floor of the example in which the vibration isolator 2 of the embodiment (FIG. 1) is attached to the lower end of the support bolt and the conventional vibration isolator 10 having a single structure shown in FIG. 7 attached to the lower end of the support bolt. A vibration test was performed on the double floor of the example.
FIG. 8 is an explanatory diagram of the vibration test.
The vibration test is performed in a two-story laboratory 11 made of reinforced concrete.
On the second floor, a double floor as a specimen is constructed in the center, and sensors are installed on the upper floor 9 and the lower floor 8 (concrete slab) of the double floor to vibrate the upper and lower floors. Measure the amount with a vibrometer.
On the first floor, a vibration device 12 such as a bang machine or a tamping machine is installed.
When the vibration device 12 on the first floor is operated, the vibration is transmitted to the lower floor of the second floor, and the lower floor 8 and the upper floor 9 vibrate. At this time, the vibration amount of the upper floor and the lower floor is measured, and the reduction amount of the vibration of the upper floor relative to the vibration of the lower floor is obtained. In the case of the example, compared with the comparative example, the reduction amount at a frequency of 50 Hz is increased by about 7 to 12 dB, demonstrating the effect of reducing the transmission of the low frequency vibration of the present invention.

1 foot member 2, 2a, 2b vibration isolator 3 inner member 31 upper surface 32 inner hole 32a bottom surface 33 ridge 4 external material 41 peripheral wall 42 bottom plate 43 ridge 5 support bolt 5a flange portion 6 receiving plate 7 receiving nut 8 lower floor 9 Upper floor 9a Lower adhesive material 9b Finishing material 10 Vibration isolator 11 Laboratory 12 Exciting device

Claims (5)

In the vibration isolator attached to the lower end of the support bolt of the foot member that supports the upper floor of the double floor,
An inner member that has a support surface for supporting the support bolt and is formed in a cylindrical shape or a columnar shape with an elastic material such as rubber;
An anti-vibration structure for a double floor, characterized in that it has an outer member that is formed in a cylindrical shape by an elastic material such as rubber, and is fitted on the inner member, and the hardness of the outer member is greater than the hardness of the inner member. Ingredients. The vibration isolator according to claim 1, wherein the hardness of the inner member is 50 to 60, and the hardness of the outer member is 65 to 75. When the outer member has a ridge on the outer peripheral surface of the inner member or the inner peripheral surface of the outer member, and the outer member is externally fitted to the inner member, the outer member is disposed between the outer peripheral surface of the inner member and the inner peripheral surface of the outer member. The vibration isolator of Claim 1 or 2 which has a clearance gap in parts other than a protrusion. The vibration isolator according to claim 3, wherein a plurality of the protrusions are formed in the longitudinal direction or a plurality of protrusions are formed in the circumferential direction.   A double floor, wherein the upper floor is supported by a foot member having the vibration isolator according to claim 1 attached to a lower end of a support bolt.

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