JP5417192B2 - Air spring and seismic isolation device - Google Patents

Description

  The present invention relates to an air spring in which a piston is disposed in a cylinder, and a seismic isolation device using the same.

  As this type of air spring, conventionally, for example, as described in Patent Document 1 below, a cylinder in which one end in the axial direction is closed and the other end is opened, and the cylinder is inserted into the cylinder from the open end side of the cylinder. And a piston that is displaceable along the axial direction relative to the cylinder, and a diaphragm that hermetically closes a gap between the outer peripheral surface of the piston and the inner peripheral surface of the cylinder. ing. The air spring having such a configuration is an air spring generally used for railway vehicles, equipment vibration isolation, and the like, and the use pressure thereof is 1 MPa or less.

  On the other hand, in recent years, a three-dimensional seismic isolation device using an air spring as a vertical spring element has been provided. When the above-described air spring is used for such a seismic isolation device, since compactness is required, a device that can withstand a working pressure of 1 MPa or more is required. However, in the air spring having the above-described configuration, the internal pressure of the cylinder can be increased only to a pressure that can be withstood by the diaphragm, and it is often impossible to cope with the operating pressure in the seismic isolation device.

  Therefore, conventionally, for example, as described in Patent Document 2 below, a double diaphragm is provided in a gap portion between the outer peripheral surface of the piston and the inner peripheral surface of the cylinder, and the internal pressure between these diaphragms is changed to the cylinder. There has been proposed an air spring that is set lower than the internal pressure and higher than the external pressure (atmospheric pressure). According to the air spring having such a configuration, it is possible to set the internal pressure of the cylinder high, and it is possible to cope with a high working pressure. In the air spring described above, an orifice is formed in the tip wall of the piston, and when air flows between the piston and the cylinder through the orifice, a damping force in the vertical direction (cylinder axial direction) is generated. Can be obtained.

JP 63-92844 A JP 2007-218391 A

  In recent years, in the field of seismic isolation devices, there has been a demand for an air spring that exhibits high damping performance in the cylinder axial direction in order to cope with rocking of the superstructure and longitudinal earthquake during an earthquake. Since the spring is only damped by the orifice, it is difficult to obtain a large damping force, and the damping performance may be insufficient with respect to the rocking of the superstructure or the longitudinal earthquake.

  The present invention takes the above-described conventional problems into consideration, an air spring that can withstand a high operating pressure while being downsized, and can obtain a large damping force in the cylinder axial direction, and An object of the present invention is to provide a seismic isolation device using the air spring.

  An air spring according to the present invention includes a cylinder, a piston that is inserted into the cylinder from an open end of the cylinder and that is displaceable along the cylinder axial direction relative to the cylinder, and an outer periphery of the piston A first diaphragm and a second diaphragm for hermetically closing a gap between the surface and the inner peripheral surface of the cylinder, wherein the first and second diaphragms are superposed on each other. One end of each of the first and second diaphragms is fixed to the piston and the other end is fixed to the cylinder, respectively, and an intermediate portion of the first and second diaphragms is mutually connected in the gap portion. Air springs are folded at positions shifted in the cylinder axial direction, and an intermediate chamber is formed between the folded portions of the first and second diaphragms. Te, the viscous fluid is filled in the middle chamber, the internal pressure of the intermediate chamber is characterized in that is higher than the low and external air pressure than the internal pressure of the cylinder.

  In the air spring described above, an intermediate chamber is formed in the gap between the inner peripheral surface of the cylinder and the outer peripheral surface of the piston, and the internal pressure in the intermediate chamber is lower than the internal pressure of the cylinder and higher than the external pressure. Therefore, even if the internal pressure of the cylinder is increased, the stress acting on the first and second diaphragms can be kept small.

  In the above-described air spring, when the piston is displaced relative to the cylinder in the cylinder axial direction, the folded portions of the first and second diaphragms are translated in the cylinder axial direction along with the displacement, and the intermediate chamber is shaped. Move in the cylinder axis direction while holding At this time, a shear stress along the cylinder axial direction acts on the viscous fluid in the intermediate chamber.

  A seismic isolation device according to the present invention is a seismic isolation device interposed between an upper structure and a lower structure, an isolator that allows relative displacement in the horizontal direction between the upper structure and the lower structure, The above-described air spring is provided.

According to this seismic isolation device, when an external force such as seismic motion is input, the upper structure and the lower structure are relatively displaced in the horizontal direction by the function of the isolator. As a result, the natural period of the superstructure is lengthened and the seismic stress received by the superstructure is relaxed.
Moreover, since the displacement in the vertical direction is allowed by the air spring, low rigidity is obtained in the vertical direction, the vertical natural period of the superstructure is lengthened, and the seismic stress received by the superstructure is alleviated. At this time, as described above, the shearing stress in the cylinder axial direction acts on the viscous fluid in the intermediate chamber, so that the vibration energy of the upper structure rocking vibration and pitching is absorbed, and the response vibration of the upper structure is attenuated.

  According to the air spring of the present invention, the internal pressure of the cylinder can be increased, so that the operating pressure can be set high. Further, since shear stress along the cylinder axial direction acts on the viscous fluid in the intermediate chamber, a large damping force in the cylinder axial direction can be obtained.

  In addition, according to the seismic isolation device of the present invention, not only rolling vibration but also vertical shaking and rocking can be absorbed, and the response vibration of the superstructure can be reliably reduced.

It is sectional drawing of the seismic isolation apparatus which has an air spring for describing embodiment of this invention. It is a fragmentary sectional view of the air spring for demonstrating embodiment of this invention.

Embodiments of an air spring and a seismic isolation device according to the present invention will be described below with reference to the drawings.
In the present embodiment, a center axis of a cylinder 2 to be described later is referred to as an “axis O”, a direction along the axis O is referred to as an “axial direction”, and a direction perpendicular to the axis O is referred to as a “radial direction”. The direction around O is the “circumferential direction”. Further, one side in the axial direction (upper side in FIG. 1) is “upper”, and the other side in the axial direction (lower side in FIG. 1) is “lower”.

  A seismic isolation device 1 shown in FIG. 1 is interposed between a lower structure 10 such as a foundation and an upper structure 11 such as a building body, and is a device for reducing response vibration of the upper structure 11 with respect to earthquake motion. As a schematic configuration of the seismic isolation device 1, an isolator 2 that allows relative displacement in the horizontal direction between the lower structure 10 and the upper structure 11 and relative displacement in the vertical direction between the lower structure 10 and the upper structure 11 are allowed. And an air spring 3. The isolator 2 and the air spring 3 are arranged in series in the vertical direction, and specifically, the air spring 3 is disposed on the isolator 2. Note that the isolator 2 may be disposed on the air spring 3 by rotating the isolator 2 and the air spring 3 upside down.

  More specifically, the isolator 2 is interposed between the lower end plate 20 fixed to the lower structure 10, the upper end plate 21 fixed to the upper structure 11, and the lower end plate 20 and the upper end plate 21. The laminated body 22 is provided.

  The lower end plate 20 and the upper end plate 21 are, for example, circular steel plates in plan view, and are arranged to face each other in the vertical direction. In addition, the lower end plate 20 and the upper end plate 21 are each formed to have a larger diameter than the cross-sectional shape of the laminate 22, and the outer peripheral portions of the lower end plate 20 and the upper end plate 21 are all around the circumference. It protrudes toward the outer side in the radial direction of the laminate 22. The lower end plate 20 is fixed to the lower structure 10 via, for example, anchor bolts, and the upper end plate 21 is fixed to an end plate portion 50 of the piston 5 of the air spring 3 described later via, for example, bolts. It is fixed to.

The laminated body 22 is a columnar body having a laminated structure in which a plurality of soft plates 23 and hard plates 24 are alternately laminated, and is formed in a substantially cylindrical shape that can be shear-deformed in the horizontal direction. A covering rubber 25 covering the outer periphery of the soft plate 23 and the hard plate 24 is formed on the outer peripheral portion of the laminate 22 over the entire periphery. The soft plate 23 and the covering rubber 24 are made of an elastically deformable vulcanized rubber formed integrally. By vulcanizing the unvulcanized soft plate 23 and the covering rubber 25 together with the plurality of hard plates 24 described above. The soft plate 23 and the covering rubber 25 are bonded to the plurality of hard plates 24 by vulcanization. This laminated body 22 has high vertical rigidity and is difficult to sink in the vertical direction, and has low horizontal rigidity and is easily sheared in the horizontal direction.
The soft plate 23 and the covering portion 25 described above may be other than rubber, and may be formed of, for example, a soft resin. Further, the hard plate 24 described above may be other than a steel plate, for example, a plate material made of hard resin.

  The air spring 3 includes a cylinder 4 and a piston 5 that is inserted into the cylinder 4 from the open end of the cylinder 4 and that can be displaced along the axial direction relative to the cylinder 4.

  The cylinder 4 is a substantially cylindrical cylindrical portion that extends along the vertical direction, and is a top cylinder that is closed at the upper end and opened at the lower end. The cylinder 4 is embedded in the lower end portion of the upper structure 11 and fixed to the upper structure 11.

  The piston 5 includes an end plate portion 50 disposed perpendicular to the axis O, and a cylinder portion 51 erected along the axial direction from the upper surface of the end plate portion 50. The end plate portion 50 is placed on the upper end plate 21 of the isolator 2 described above, and is fixed to the upper end plate 21 with a bolt or the like (not shown). The cylindrical portion 51 is a substantially cylindrical cylindrical portion whose outer diameter is smaller than the inner diameter of the cylinder 4. The cylindrical portion 51 is disposed coaxially with the cylinder 4 with the axis O as a common axis and is inserted inside the cylinder 4. .

  A gap 6 is formed over the entire circumference in the circumferential direction between the outer peripheral surface of the piston 5 (cylindrical portion 51) and the inner peripheral surface of the cylinder 4 described above. The air spring 3 is provided with double diaphragms 7 and 8 overlapped with each other, and the gap 6 is airtightly closed by these diaphragms 7 and 8. The above-described diaphragms 7 and 8 are so-called rolling seal members, each of which is formed of a flexible cylindrical tube, for example, a rubber film formed in a cylindrical shape. The diaphragms 7, 8 are folded back in a substantially U shape at the gap 6, one end is fixed to the piston 5, and the other end is fixed to the cylinder 4. The pair of diaphragms 7 and 8 are folded back at positions shifted from each other in the axial direction, and the folded portion 70 of one diaphragm (first diaphragm 7) and the folded portion 80 of the other diaphragm (second diaphragm 8). And are spaced apart in the axial direction.

  More specifically, as shown in FIG. 2, the first diaphragm 7 has a double cylinder shape in which the lower ends of the inner and outer cylinders are connected to each other, and the schematic configuration thereof is along the inner peripheral surface of the cylinder 4. The formed outer cylinder part 71, the inner cylinder part 72 formed along the outer peripheral surface of the piston 5 (cylinder part 51), the lower end of the outer cylinder part 71 and the lower end of the inner cylinder part 72 are extended over the entire circumference. Are connected to each other, an annular portion 73 formed along the tip surface of the piston 5 (cylinder portion 51) from the upper end of the inner cylinder portion 72, and the entire circumference radially inward from the upper end of the outer cylinder portion 71. A cylinder-side fixing part 74 that is projected over the cylinder 4 and fixed to the ceiling surface of the cylinder 4, and is suspended from the inner edge of the annular part 73 along the inner peripheral surface of the piston 5 (cylinder part 51). A piston side fixing portion 75 fixed to the peripheral surface. The outer peripheral surface of the outer cylindrical portion 71 is in close contact with the inner peripheral surface of the cylinder 4 so as to be peelable, and the inner peripheral surface of the inner cylindrical portion 72 is the outer peripheral surface of the piston 5 (cylinder portion 51). On the other hand, it is closely attached to be peeled.

  Further, the second diaphragm 8 has a double cylinder shape in which the lower ends of the inner and outer cylinders are connected to each other, and is arranged in a state of being overlapped with the first diaphragm 7 from the upper side in the axial direction. As a schematic configuration of the second diaphragm 8, the outer cylinder portion 81 formed along the inner peripheral surface of the outer cylindrical portion 71 of the first diaphragm 7 and the outer peripheral surface of the inner cylindrical portion 72 of the first diaphragm 7 are used. The inner cylindrical portion 82 formed by connecting the lower end of the outer cylindrical portion 81 and the lower end of the inner cylindrical portion 82 over the entire circumference, and the circle of the first diaphragm 7 from the upper end of the inner cylindrical portion 82. An annular portion 83 formed along the upper surface of the annular portion 73, and a cylinder side fixing portion 84 that protrudes from the upper end of the outer cylinder portion 81 radially inward and is fixed to the ceiling surface of the cylinder 4. And a piston side fixing portion 85 that is suspended from the inner edge of the annular portion 83 along the inner surface of the piston side fixing portion 75 of the first diaphragm 7 and fixed to the inner peripheral surface of the piston 5. The outer peripheral surface of the outer cylindrical portion 81 of the second diaphragm 8 is in close contact with the inner peripheral surface of the outer cylindrical portion 71 of the first diaphragm 7 so as to be peelable, and the inner cylindrical portion of the second diaphragm 8. The inner peripheral surface 82 is in close contact with the outer peripheral surface of the inner cylindrical portion 72 of the first diaphragm 7 so as to be peelable. Further, the folded portion 80 of the second diaphragm 8 is disposed at a distance above the folded portion 70 of the first diaphragm 7 in the axial direction.

  In addition, an intermediate chamber 9 is formed between the folded portions 70 and 80 described above, which translates in the axial direction in accordance with the relative displacement of the cylinder 4 and the piston 5 in the axial direction. The intermediate chamber 9 is a sealed space interposed between the inside and the outside of the cylinder 4. The folded portion 70, the outer cylinder 71, the inner cylinder 72, and the second diaphragm 8 of the first diaphragm 7 described above. It is defined by the folded portion 80.

The intermediate chamber 9 slides on the inner surface of the intermediate chamber 9 following the parallel movement of the intermediate chamber 9 accompanying the relative displacement of the cylinder 4 and the piston 5 in the axial direction. Displaceable viscous fluid 12 is filled. The viscous fluid 12 is a fluid liquid or semi-solid, such as a highly viscous fluid such as silicone oil.
Further, the internal pressure Pb of the intermediate chamber 9 is lower than the internal pressure Pa of the cylinder and higher than the external pressure Po (atmospheric pressure). In addition, it is preferable to provide a pressure adjusting means (not shown) for adjusting the internal pressure Pb of the intermediate chamber 9.

  Next, the operation of the air spring 3 and the seismic isolation device 1 having the above-described configuration will be described.

  When earthquake motion is input to the lower structure 10 described above, the laminated body 22 of the isolator 2 undergoes shear deformation in the horizontal direction, and the lower structure 10 and the upper structure 11 are relatively displaced in the horizontal direction. Thereby, the natural period of the upper structure 11 becomes longer, and the seismic stress received by the upper structure 11 is relaxed.

  Further, when vertical ground motion is input during an earthquake, the piston 5 of the air spring 3 is displaced in the axial direction relative to the cylinder 4. Thereby, the vertical displacement of the lower structure 10 and the upper structure 11 is allowed, the vertical natural period of the upper structure 11 is lengthened, and the vertical earthquake stress received by the upper structure 11 is also alleviated. At this time, as shown in FIGS. 3A and 3B, the folded portions 70 and 80 of the first and second diaphragms 7 and 8 are axially moved in accordance with the relative displacement between the piston 5 and the cylinder 4. The intermediate chamber 9 moves in the axial direction while maintaining its shape. That is, the first diaphragm 7 and the second diaphragm 8 are respectively deformed by changing their respective folding positions in accordance with the relative displacement between the piston 5 and the cylinder 4, whereby the intermediate chamber 9 remains in a constant shape in the axial direction. It is displaced to.

  For example, as shown in FIG. 3B, when the piston 5 is relatively displaced axially upward with respect to the cylinder 4, the piston 5 fixing portions 75 and 85 of the first diaphragm 7 and the second diaphragm 8 and the circle are moved by the piston 5. The ring portions 73 and 83 are pushed upward in the axial direction. As a result, the outer cylindrical portion 71 of the first diaphragm 7 that is in close contact with the inner peripheral surface of the cylinder 4 is peeled off from the lower end side and folded back radially inward, and then stretched on the outer peripheral surface of the piston 5 (cylinder portion 51). In addition, the outer cylinder portion 81 of the second diaphragm 8 which is in close contact with the inner peripheral surface of the outer cylinder portion 71 of the first diaphragm 7 is peeled off from the lower end side and folded back radially inwardly. It sticks to the outer peripheral surface of the inner cylindrical portion 72 of the diaphragm 7. As a result, the folded portion 70 of the first diaphragm 7 and the folded portion 80 of the second diaphragm 8 are translated parallel to each other in the axial direction while maintaining a constant distance from each other, and the intermediate chamber 9 remains in a fixed shape with a shaft. Displaces upward in the direction.

  Further, when the intermediate chamber 9 is displaced in the axial direction with a constant shape, a shear stress F along the axial direction acts on the viscous fluid 12 filled in the intermediate chamber 9. A damper effect (damping force) due to the shear stress F is obtained.

  According to the air spring 3 described above, the intermediate chamber 9 is formed in the gap 6 between the inner peripheral surface of the cylinder 4 and the outer peripheral surface of the piston 5, and the internal pressure Pb of the intermediate chamber 9 is higher than the internal pressure Pa of the cylinder. Since it is low and higher than the external pressure Po (atmospheric pressure), the stress acting on the first and second diaphragms 7 and 8 can be kept small even if the internal pressure of the cylinder 4 is increased. Therefore, the internal pressure of the cylinder 4 can be increased and the working pressure of the air spring 3 can be set high.

Further, according to the air spring 3 described above, since the shear stress F acts on the viscous fluid 12 in the intermediate chamber 9 when the piston 5 and the cylinder 4 are displaced in the axial direction, a large damping force in the axial direction is generated. Can be obtained.
Therefore, according to the above-described seismic isolation device 1, not only the vibration energy of rolling but also the vibration energy of pitching and rocking can be absorbed, and the response vibration of the upper structure 11 can be reliably reduced.

As mentioned above, although embodiment of the air spring which concerns on this invention was described, this invention is not limited to above-described embodiment, In the range which does not deviate from the meaning, it can change suitably.
For example, in the above-described embodiment, the diaphragms 7 and 8 are provided in a double manner, but the present invention can also provide a triple or more diaphragm. Thereby, an intermediate chamber having two or more layers can be formed in the gap 6. That is, the second and third intermediate chambers may be formed on the upper side (inside the cylinder 4) or the lower side (opening end side of the cylinder 4) of the intermediate chamber 9 filled with the viscous fluid 12. Further, the second and third intermediate chambers may be filled with the same viscous fluid 12 as the viscous fluid 12 in the intermediate chamber 9 described above, or a viscous fluid or gas different from the viscous fluid 12 described above. May be filled. In the case where two or more intermediate chambers are formed, the internal pressure of these chambers may be set to be at least equal to or higher than the internal pressure of the intermediate chamber adjacent to the opening end side (lower side in FIG. 1) of the cylinder 4. It is preferable to set it so that it gradually becomes lower from the inner side to the outside.

  In the above-described embodiment, the air spring 3 that forms the seismic isolation device 1 in combination with the isolator 2 has been described. However, the air spring according to the present invention can be applied to devices other than the seismic isolation device 1. For example, it can also be used for automobiles, railway vehicles, and other devices.

  Further, in the above-described embodiment, the seismic isolation element including the laminated body 22 is provided as the isolator 2, but the isolator in the present invention may be other than the laminated body 22, for example, a sliding bearing or It is also possible to use a rolling bearing.

  In addition, in the range which does not deviate from the main point of this invention, it is possible to replace suitably the component in above-mentioned embodiment with a well-known component, and you may combine the above-mentioned modification suitably.

DESCRIPTION OF SYMBOLS 1 Seismic isolation device 2 Isolator 3 Air spring 4 Cylinder 5 Piston 6 Gap part 7 1st diaphragm 8 2nd diaphragm 9 Intermediate | middle chamber 10 Lower structure 11 Upper structure 12 Viscous fluid

Claims (2)

A cylinder, a piston inserted into the cylinder from the open end of the cylinder and displaceable along the cylinder axial direction relative to the cylinder, an outer peripheral surface of the piston, and an inner peripheral surface of the cylinder A first diaphragm and a second diaphragm for hermetically closing a gap between the first diaphragm and the second diaphragm,
The first and second diaphragms are made of flexible cylinders stacked on top of each other, and one end of each of the first and second diaphragms is fixed to the piston and the other end is fixed to the cylinder. The intermediate portion of the first and second diaphragms is folded at a position shifted from each other in the cylinder axial direction in the gap, and an intermediate chamber is formed between the folded portions of the first and second diaphragms. In spring,
An air spring, wherein the intermediate chamber is filled with a viscous fluid, and an internal pressure of the intermediate chamber is lower than an internal pressure of the cylinder and higher than an external air pressure. A seismic isolation device interposed between the upper structure and the lower structure,
An isolator that allows relative displacement in the horizontal direction between the upper structure and the lower structure, and the air spring according to claim 1.

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