Friction Damper

Abstract

To provide a friction damper or the like that can be easily manufactured and that can preferably obtain a vibration damping effect. [Solution] In a friction damper (1), a sliding plate (3) and friction plates (4) on both sides of the sliding plate (3) in the thickness direction are fastened together using bolts (5), applying a pressing force to the friction plate (4) and pressing the friction plate (4) toward the sliding plate (3). A transmission mechanism (10) for transmitting the pressing force is provided between the head and nut (6) of the bolt (5) and the friction plate (4). The transmission mechanism (10) includes a support plate (7) and a perforated plate (8). The support plate (7) and the perforated plate (8) have holes (71, 81) through which the shank of the bolt (5) passes, and the hole (81) of the perforated plate (8) has a larger cross-sectional area than the hole (71) of the support plate (7) and a smaller cross-sectional area than the outline of the plate surface of the support plate (7). The hole (81) encompasses the hole (71) of the support plate (7) and has a cross-section of a size that is encompassed within the outline of the plate surface of the support plate (7). The perforated plate (8) transmits the pressing force at a position spaced apart from the shank of the bolt (5).

Description

[Technical Field]

[0001] The present invention relates to a friction damper. [Background technology]

[0002] Friction dampers are sometimes used in buildings to suppress vibrations caused by earthquakes, etc. Friction dampers have a sliding plate that moves back and forth during an earthquake, etc., sliding against a friction plate, and the friction between the sliding plate and the friction plate absorbs vibration energy and attenuates the vibration.

[0003] Patent Documents 1 and 2 disclose friction dampers that press friction plates on both sides of a sliding plate toward the sliding plate by tightening bolts. In Patent Document 1, bolts are passed through openings in disc springs and press the friction plates via the disc springs, thereby suppressing fluctuations in pressing force and ensuring stable vibration energy absorption performance through friction. In the friction damper of Patent Document 2, the pressing force from the bolts is transmitted to the friction plates via first and second support plates, and the second support plate, which is located on the friction plate side, is provided with a ridge that contacts the first support plate. This distributes the pressing force from the ridge to the friction plates, thereby suppressing localized wear of the friction plates due to concentrated pressing force and ensuring a vibration-damping effect. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4019511 [Patent Document 2] Patent No. 6437328 Summary of the Invention [Problem to be solved by the invention]

[0005] In Patent Document 1, a disc spring is used to suppress fluctuations in the pressing force, but the disc spring is a pre-made product and the diameter of its opening does not generally match the diameter of the bolt. If the position of the bolt is shifted from the center of the disc spring's opening, the pressing force will not be transmitted evenly, so in Patent Document 1, a guide ring with an outer diameter equal to the diameter of the disc spring's opening is provided around the bolt, and the guide ring fixes the bolt to the center of the disc spring's opening.

[0006] However, the guide ring increases the number of parts, making the friction damper more time-consuming and costly to manufacture. Furthermore, several disc springs are stacked to provide the necessary pressure, but friction between the disc springs reduces the pressure, potentially preventing the desired vibration damping effect.

[0007] Furthermore, in Patent Document 2, protrusions are formed on the support plate to distribute and transmit the pressing force, but such processing is time-consuming and increases the manufacturing cost.

[0008] The present invention has been made in view of the above problems, and has as its object to provide a friction damper or the like that can be easily manufactured and that can preferably obtain a vibration damping effect. [Means for solving the problem]

[0009] The present invention, which aims to solve the above-mentioned problems, is a friction damper that absorbs vibration energy by friction when a sliding plate slides on a friction plate, wherein the sliding plate and the friction plates on both sides in the thickness direction of the sliding plate are fastened together using bolts, and a pressing force is applied to the friction plate from a pressing portion, which is the head of the bolt or a nut fastened to the bolt, and the friction plate is pressed against the sliding plate, and the sliding plate moves relative to the bolt when sliding, and a transmission mechanism that transmits the pressing force is provided between the pressing portion and at least one of the friction plates. the transmission mechanism includes a support plate and a perforated plate, the support plate and the perforated plate being arranged in this order from the pressing portion toward the friction plate, the support plate and the perforated plate having a hole through which the shank of the bolt passes, the hole of the perforated plate having a cross-sectional area larger than that of the hole in the support plate and smaller than that of the outline of the plate surface of the support plate, the hole having a cross-sectional area that includes the hole in the support plate and is included in the outline of the plate surface of the support plate, and the pressing force is transmitted by the perforated plate at a position separated from the shank of the bolt.

[0010] The friction damper of the present invention can transmit the pressing force generated by tightening the bolt to the friction plate through a transmission mechanism with a simple configuration using the support plate and perforated plate, and can suppress fluctuations in the pressing force depending on the degree of deflection of the support plate. Furthermore, since the pressing force is transmitted to the friction plate from the outer edge of the hole in the perforated plate, which is located away from the bolt, concentration of pressing force near the bolt shaft can be avoided compared to when only a support plate is used. This allows the vibration energy absorption performance through friction to be stably exerted, and a suitable vibration control effect can be obtained. Furthermore, the friction damper of the present invention can be easily manufactured because it does not require the use of disc springs in the transmission mechanism or the processing of ridges on the support plate.

[0011] The holes in the perforated plate are preferably circular. In this case, the distance from the shank of the bolt to the outer edge of the hole in the perforated plate can be made uniform around the periphery of the hole, and the pressing force of the bolt can be transmitted evenly around the periphery of the hole.

[0012] It is preferable that the transmission mechanism further includes an outer plate disposed between the perforated plate and the friction plate. This allows the pressing force of the bolts to be distributed over a wider area via the outer panel.

[0013] The sliding plate preferably has an elongated hole extending along the sliding direction of the sliding plate, through which the shank of the bolt is passed. The hole in the sliding plate may have any shape as long as it allows the sliding plate to move relative to the bolt, and is typically an elongated hole extending along the sliding direction of the sliding plate.

[0014] It is desirable that a plurality of the bolts be provided, the support plate be provided for each of the plurality of bolts, and the perforated plate be provided in common to the plurality of bolts. The pressure on the friction plate can be adjusted by increasing or decreasing the number of bolts. When the bolts are far apart, it may be more reasonable to provide a perforated plate for each of the bolts individually, but by providing a common perforated plate for multiple bolts, the friction damper structure can be simplified. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a friction damper or the like that can be easily manufactured and that can preferably obtain a vibration damping effect. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 2 is a diagram showing an example of installation of the friction damper 1. [Figure 2] FIG. 2 is a cross-sectional view of the friction damper 1. [Figure 3] FIG. 2 is a diagram showing an elevation of the friction damper 1. [Figure 4] 1 is a diagram showing a bearing plate 7, a perforated plate 8, an outer plate 2, a friction plate 4, and a sliding plate 3. [Figure 5] 3A and 3B are diagrams illustrating the relative movement of the sliding plate 3. [Figure 6] 4A and 4B are diagrams illustrating the deflection of the support plate 7. FIG. [Figure 7]FIG. 3 is a diagram schematically showing the distribution of pressing force applied to the friction plate 4. [Figure 8] 10A and 10B are diagrams showing modified examples of the friction damper 1. [Figure 9] FIG. 10 is a diagram showing a modified example of the support plate 7. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[0018] 1 is a diagram showing an example of installation of a friction damper 1 according to an embodiment of the present invention. The friction damper 1 is attached, for example, between the opposing ends of upper and lower partitions 40 within the structural plane of a frame formed by columns 20 and beams 30. When horizontal vibrations occur due to an earthquake or the like, the friction damper 1 absorbs vibration energy through friction between a friction plate and a sliding plate, which will be described later.

[0019] The studs 40 are vertical pillars and are attached to the upper and lower beams 30. In this embodiment, H-shaped steel beams are used as the studs 40, but this is not limitative. There are no particular limitations on the structural types of the columns 20 and beams 30.

[0020] Fig. 2 is a diagram showing a cross section of the friction damper 1, taken along line AA in Fig. 1. Fig. 3 is a diagram showing an elevation of the friction damper 1, seen from direction B in Fig. 2.

[0021] The friction damper 1 includes an outer plate 2, a sliding plate 3, a friction plate 4, a bolt 5, a nut 6, a bearing plate 7, and a perforated plate 8. The outer plate 2, the sliding plate 3, the friction plate 4, the bearing plate 7, and the perforated plate 8 are arranged so that their plate surfaces are in the in-plane direction of the structural surface of the frame.

[0022] A pair of outer plates 2 are provided on the front and back of the sliding plate 3, and are disposed between the friction plate 4 and the perforated plate 8. "Front and back" refer to both sides in the thickness direction of the sliding plate 3. The outer plates 2 are formed from a steel material such as carbon steel, but are not limited to this. Each outer plate 2 has a hole 21 for passing the shank of a bolt 5 therethrough.

[0023] The sliding plate 3 is a plate-shaped sliding material. The sliding plate 3 moves back and forth horizontally within the structural surface of the frame due to vibrations such as earthquakes. The direction of movement of the sliding plate 3 corresponds to the normal direction to the paper surface of FIG. 2 and the left-right direction in FIG. 3. The sliding plate 3 has a hole 31 through which the shaft of the bolt 5 passes.

[0024] The friction plates 4 are plate-shaped friction materials that are fixed to the surface of each outer plate 2 facing the sliding plate 3 with an adhesive or a fixing jig (not shown), and are supported by the outer plate 2. The friction plates 4 provided on each outer plate 2 come into contact with the front and back surfaces of the sliding plate 3. When the sliding plate 3 moves back and forth, it slides on the friction plates 4, and friction occurs between the sliding plate 3 and the friction plates 4, causing vibration energy from earthquakes and the like to be consumed (absorbed) through frictional heat, etc.

[0025] The sliding plate 3 is made of, for example, stainless steel, and the friction plate 4 is made of a resin material. However, the materials of the sliding plate 3 and the friction plate 4 are not limited to these. For example, the sliding plate 3 and the friction plate 4 may be made of metal such as aluminum or an alloy, and friction may occur between these metals.

[0026] The bolt 5 is a headed bolt, and for example, a high-strength bolt is used. The shank of the bolt 5 passes through a hole 21 in one of the outer plates 2 (the left outer plate 2 in the example of Figure 2), a hole 31 in the sliding plate 3, and a hole 21 in the other outer plate 2 (the right outer plate 2 in the example of Figure 2), and protrudes from the other outer plate 2. A nut 6 is fastened onto the protruding portion. The bolt 5 fastens the sliding plate 3 to the friction plates 4 on its front and back, and the head of the bolt 5 and the nut 6 press the friction plates 4 on the front and back of the sliding plate 3 toward the sliding plate 3. The head of the bolt 5 and the nut 6 function as pressing parts that press the friction plates 4 toward the sliding plate 3.

[0027] The support plate 7 and perforated plate 8, together with the outer plate 2, constitute a transmission mechanism 10. The transmission mechanism 10 transmits the pressing force generated by the tightening of the bolt 5 to the friction plate 4, and is provided between the head of the bolt 5 and the nut 6 (pressing portion) and the friction plate 4. The support plate 7 and perforated plate 8 are arranged in this order from the head of the bolt 5 or the nut 6 toward the friction plate 4.

[0028] The support plate 7 is an elastic plate-like member made of steel such as carbon steel. The support plate 7 has a hole 71 in its center through which the shaft of the bolt 5 passes. In this embodiment, the support plate 7 is a circular plate. In this embodiment, a plurality of bolts 5 (two in the example of FIG. 3) are provided, and a support plate 7 is provided for each bolt 5.

[0029] The perforated plate 8 is provided between the support plate 7 and the outer plate 2. The perforated plate 8 has holes 81 through which the shanks of the bolts 5 pass. The perforated plate 8 is made of steel such as carbon steel, and is fixed to the surface of the outer plate 2 opposite the friction plate 4 by adhesive, screws (not shown), welding, or the like. In this embodiment, the perforated plate 8 is rectangular, and one perforated plate 8 is provided in common for multiple bolts 5. The perforated plate 8 has holes 81 corresponding to each bolt 5.

[0030] 4(a) is a diagram showing an elevation of the support plate 7 and the perforated plate 8, and omits components other than the support plate 7 and the perforated plate 8. As shown in FIG. 4(a), the hole 71 in the support plate 7 and the hole 81 in the perforated plate 8 are circular and are arranged concentrically around the shank of the bolt 5.

[0031] The hole 81 in the perforated plate 8 has a larger cross-sectional area than the hole 71 in the support plate 7, but a smaller cross-sectional area than the area of ​​the outline of the plate surface of the support plate 7. The hole 81 has a cross-section that is large enough to encompass the hole 71 in the support plate 7 and be encompassed by the outline of the plate surface of the support plate 7. For example, the radius of the support plate 7 is made 2.5 mm or more larger than the radius of the hole 81 so that the hole 81 in the perforated plate 8 is encompassed by the outline of the plate surface of the support plate 7, even if the support plate 7 is misaligned with respect to the perforated plate 8, due to the play of the hole 21 in the outer plate 2 and the hole 71 in the support plate 7 relative to the shank of the bolt 5.

[0032] The specifications of the bearing plate 7, perforated plate 8, and their holes 71, 81 can be determined arbitrarily as long as they satisfy the above conditions, and the bearing plate 7 and perforated plate 8 can be easily manufactured by simply cutting and drilling. For example, by matching the diameter of the hole 71 in the bearing plate 7 to the shank diameter of the bolt 5, the aforementioned guide ring etc. becomes unnecessary.

[0033] FIG. 4(b) is a diagram showing an elevation of the outer plate 2 and the friction plate 4, and omits components other than the outer plate 2 and the friction plate 4. The outer plate 2 has a plurality of holes 21 for passing a plurality of bolts 5. The friction plates 4 are arranged on both sides of each hole 21 in the plane of the outer plate 2 in a direction perpendicular to the sliding direction of the sliding plate 3. The sliding direction corresponds to the left-right direction in FIG. 4(b), and the direction perpendicular to the sliding direction corresponds to the up-down direction in FIG. 4(b). This is also true for the next FIG. 4(c).

[0034] 4(c) is a diagram showing an elevation of the sliding plate 3, and omits components other than the sliding plate 3. The holes 31 of the sliding plate 3 are elongated holes that extend along the sliding direction of the sliding plate 3, and multiple bolts 5 are passed through the holes 31. This allows the sliding plate 3 to move relative to the bolts 5, as shown in FIG. 5. It is also possible to provide a hole 31 for each bolt 5.

[0035] The sliding plate 3 is fixed to one of the studs 40 (the lower stud 40 in FIG. 1 in this embodiment) using a high-strength bolt or the like.

[0036] One end of the plate 80 is fixed to the other stud 40 (the upper stud 40 in Figure 1 in this embodiment) using a high-strength bolt or the like, as described above. The other end of the plate 80 is placed between the front and back outer plates 2, and the other end of the plate 80 and the front and back outer plates 2 are fastened together using a high-strength bolt 60 and a nut 70. Reference numeral 22 in Figure 4(b) denotes a hole in the outer plate 2 through which the shank of the high-strength bolt 60 passes. Furthermore, plate-shaped fillers 90 are placed on the front and back of the plate 80 according to the difference between the spacing between the front and back outer plates 2 and the thickness of the plate 80.

[0037] In this embodiment, the pressing force generated by tightening the bolt 5 is first transmitted from the head of the bolt 5 and the nut 6 to the support plate 7. The pressing force is then transmitted from the support plate 7 to the perforated plate 8 at the outer edge of the hole 81 in the perforated plate 8 where the support plate 7 and the perforated plate 8 overlap, and then transmitted from the perforated plate 8 to the friction plate 4 via the outer plate 2.

[0038] At this time, the support plate 7 bends slightly to the extent that it does not come into contact with the outer plating 2, as shown in Figure 6. The support plate 7 can suppress fluctuations in pressing force by changing the degree of its bending, and according to experiments conducted by the inventors, this effect was found to be comparable to that of using a disc spring. For the sake of explanation, the bending of the support plate 7 is shown exaggerated in Figure 6.

[0039] In this embodiment, the perforated plate 8 allows the pressure force generated by tightening the bolt 5 to be distributed and transmitted over a wide area of ​​the friction plate 4. Fig. 7(a) is a diagram showing a schematic diagram of the distribution of the pressure force applied to the friction plate 4, with the magnitude of the pressure force being represented by grayscale shading. In the diagram, the greater the pressure force, the darker (blacker) it is represented.

[0040] In this embodiment, by providing the perforated plate 8, the pressing force is transmitted to the overlapping portion of the support plate 7 and the perforated plate 8, i.e., the position that contacts the outer edge of the hole 81 in the perforated plate 8, which is away from the shank of the bolt 5. This distributes the pressing force over a wide area of ​​the friction plate 4. On the other hand, FIG. 7(b) shows the distribution of the pressing force when the perforated plate 8 is not present, similar to FIG. 7(a), and the pressing force is transmitted in a concentrated manner near the shank of the bolt 5.

[0041] In this embodiment, as shown in Fig. 7(a), the pressing force is dispersed over a wide area of ​​the friction plate 4, which prevents localized wear of the friction plate 4 and allows the vibration energy absorption performance due to the friction between the sliding plate 3 and the friction plate 4 to be stably exhibited. On the other hand, if the pressing force is concentrated as shown in Fig. 7(b), the friction plate 4 may be worn locally, which may prevent the performance from being stably exhibited.

[0042] As explained above, the friction damper 1 of this embodiment can transmit the pressing force caused by tightening the bolt 5 to the friction plate 4 by the transmission mechanism 10 with a simple configuration using the support plate 7 and perforated plate 8, and can also suppress fluctuations in the pressing force depending on the degree of deflection of the support plate 7. Furthermore, since the pressing force is transmitted to the friction plate 4 from the outer edge of the hole 81 in the perforated plate 8, which is located at a distance from the bolt 5, it is possible to avoid concentration of the pressing force near the shaft of the bolt 5 compared to when only the support plate 7 is used. This allows the vibration energy absorption performance by friction to be stably exhibited, and an appropriate seismic damping effect to be obtained.

[0043] Furthermore, the friction damper 1 of this embodiment can be easily manufactured because there is no need to use disc springs in the transmission mechanism 10 or to process ridges on the support plate. Furthermore, because the friction damper 1 can be made compact and the overall thickness of the friction damper 1 can be reduced, it becomes possible to use readily available high-strength bolts of standard length as the bolts 5, further reducing manufacturing costs.

[0044] Furthermore, in this embodiment, because the holes 81 of the perforated plate 8 are circular, the distance from the shank of the bolt 5 to the outer edge of the hole 81 can be made uniform around the circumferential direction of the hole 81, and the pressing force of the bolt 5 can be transmitted evenly around the circumferential direction of the hole 81. The distance from the shank of the bolt 5 to the outer edge of the hole 81, the size of the friction plate 4, and the like can be determined depending on the desired friction force, etc. Note that the holes 81 can have other shapes depending on the usage mode of the friction damper 1 and the shape and arrangement of the friction plate 4, but from the perspective of transmitting the pressing force evenly, even if the holes are not circular, they are preferably a regular polygonal shape of at least a regular hexagon.

[0045] Furthermore, since the transmission mechanism 10 includes the outer plate 2 disposed between the perforated plate 8 and the friction plate 4, the pressing force of the bolts 5 can be dispersed over an even wider range via the stress generated in the outer plate 2.

[0046] In this embodiment, the hole 31 in the sliding plate 3 through which the shank of the bolt 5 passes is an elongated hole extending in the sliding direction of the sliding plate 3, allowing the sliding plate 3 to move relative to the bolt 5. However, the hole 31 in the sliding plate 3 is not limited to an elongated hole as long as it allows the sliding plate 3 to move relative to the bolt 5. For example, it may be a circular hole having a diameter larger than the shank diameter of the bolt 5.

[0047] Furthermore, the pressing force on the friction plate 4 can be adjusted by increasing or decreasing the number of bolts 5, but in this embodiment, one perforated plate 8 is provided in common for multiple bolts 5. This simplifies the configuration of the friction damper 1. However, it is also possible to provide a perforated plate 8 for each bolt 5. In cases where the bolts 5 are far apart, for example, it may be more reasonable to provide individual perforated plates 8.

[0048] Furthermore, in the friction damper 1 of this embodiment, a transmission mechanism 10 is provided for each of the friction plates 4 on the front and back of the sliding plate 3, but it is also possible to provide a transmission mechanism 10 for only one of the friction plates 4. For example, as shown in FIG. 8(a) in a cross section similar to FIG. 2, it is also possible to omit the perforated plate 8 on the nut 6 side. In this case, the transmission mechanism 10 of this embodiment is configured only on the head side of the bolt 5. On the nut 6 side, only the support plate 7 and the outer plate 2 are arranged, and the transmission mechanism 10 of this embodiment is not configured. Note that a screw hole may be provided in the support plate 7 to screw in the shank of the bolt 5, in which case the nut 6 can be omitted.

[0049] In this embodiment, the sliding plate 3 and the friction plate 4 are in direct contact with each other, but as shown in Fig. 8(b), a configuration may be adopted in which plate-shaped sliding portions 33 provided on the front and back of the main body of the sliding plate 3 are in contact with the friction plate 4. In this case, only the sliding portions 33 can be made of a stainless steel plate or the like that is resistant to wear, and the main body of the sliding plate 3 can be made of another material, for example, cheaper carbon steel, thereby reducing costs.

[0050] Furthermore, although the support plate 7 is a circular plate in this embodiment, it may have other shapes. For example, as shown in FIG. 9, which is an elevation view similar to FIG. 4(a), the outer shape of the support plate 7 may be polygonal. In the example of FIG. 9, the outer shape of the support plate 7 is octagonal. This makes it easier to process the support plate 7. In this case as well, the pressing force is transmitted by the outer edges of the holes 81 in the perforated plate 8.

[0051] The shapes of the other components of the friction damper 1, such as the outer plate 2, sliding plate 3, friction plate 4, and perforated plate 8, can also be changed as appropriate, taking into consideration the installation environment and vibration control effect of the friction damper 1. For example, the friction plate 4 can be an arc-shaped component that follows the overlapping portion of the support plate 7 and the perforated plate 8.

[0052] Furthermore, in this embodiment, the friction damper 1 is installed between the studs 40, but the installation location of the friction damper 1 is not limited to this. For example, a brace can be provided within the structural surface of the frame made up of the columns 20 and beams 30, and the friction damper 1 can be interposed at the end of the brace. It is also possible to install the friction damper 1 at a location other than the structural surface of the frame made up of the columns 20 and beams 30, such as a connecting beam (not shown) that connects the structural members of a building.

[0053] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to these examples. It is clear that those skilled in the art can conceive of various modifications and alterations within the scope of the technical ideas disclosed in this application, and it is understood that these modifications and alterations also fall within the technical scope of the present invention. [Explanation of symbols]

[0054] 1: Friction damper 2: Outer panel 3: Sliding plate 4:Friction plate 5: Bolt 6: Nut 7: Support plate 8: Perforated plate 10: Transmission mechanism 20: Pillar 21, 22, 31, 71, 81: Hole 30: Beam 33: Sliding part 40: Stud

Claims

1. A friction damper that absorbs vibration energy by friction when a sliding plate slides on a friction plate, The sliding plate and the friction plates on both sides of the sliding plate in the thickness direction are fastened together using bolts, and a pressing force is applied to the friction plate from a pressing portion, which is a head of the bolt or a nut fastened to the bolt, and the friction plate is pressed against the sliding plate, The sliding plate moves relative to the bolt when sliding, a transmission mechanism for transmitting the pressing force is provided between the pressing portion and at least one of the friction plates, the transmission mechanism includes a bearing plate and a perforated plate; the support plate and the perforated plate are arranged in this order from the pressing portion toward the friction plate, the support plate and the perforated plate have holes through which the shanks of the bolts pass, the holes in the perforated plate have a cross-sectional area larger than that of the holes in the support plate and smaller than that of the outline of the plate surface of the support plate, and have a cross-section of a size that includes the holes in the support plate and is included within the outline of the plate surface of the support plate; A friction damper characterized in that the pressing force is transmitted by the perforated plate at a position spaced apart from the shank of the bolt.

2. 2. The friction damper of claim 1, wherein the holes in the perforated plate are circular.

3. The transmission mechanism includes:

2. The friction damper of claim 1, further comprising an outer plate disposed between said perforated plate and said friction plate.

4. 2. The friction damper according to claim 1, wherein the sliding plate has an elongated hole extending along the sliding direction of the sliding plate, through which the shank of the bolt passes.

5. A plurality of the bolts are provided, The support plate is provided for each of the plurality of bolts, 2. The friction damper according to claim 1, wherein the perforated plate is provided in common for a plurality of the bolts.

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