JP2001108016A - Base isolation and vibration resistant device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a base isolation and vibration resistant device having a low cost and taking a small space. SOLUTION: A sliding plate 31 is coupled to a foundation 10, an elastic body 32 is secured to the lower surface of a floor frame 21, a supporting member 33 is secured to the elastic body, an auxiliary elastic body 34 is secured to the supporting member, an auxiliary supporting member 35 is secured to the auxiliary elastic body, and a frictional pad 36 is secured to the auxiliary member. A horizontal displacement locking pin 37 is fixed on the lower surface of the floor frame, and is extended downward by passing through the supporting member, the auxiliary elastic member, and the auxiliary supporting member. The first pin hole 33A of the supporting member and the second pin hole 35A of the auxiliary supporting member through which the horizontal displacement locking pin passes are larger than the diameter of the horizontal displacement locking pin, and a gap (a) of several mm is secured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seismic isolation device capable of suppressing not only the transmission of earthquake vibrations to a structure but also the transmission of minute vibrations caused by transportation or the like to the structure.

[0002]

2. Description of the Related Art Various types of seismic isolation devices have been developed to attenuate the transmission of seismic vibration to structures. There are various types of seismic isolation devices. For example, there is a friction type seismic isolation device using a frictional force. FIG. 7 is a diagram showing the structure of an example of a conventional friction-type seismic isolation device, which is provided on a slide plate 1 fixed on a base 10 and a lower surface of a floor member 20 of a structure to be isolated. It comprises a friction pad 2 installed on a sliding plate 1. In addition, in this specification, a base shows the foundation or floor of a building which moves integrally with the movement of the ground.

FIG. 8A is an explanatory view of the seismic isolation effect of the above-mentioned friction type seismic isolation device at the time of an earthquake. The left side shows the acceleration He in the horizontal direction of the earthquake on the base 10, and the right side shows the acceleration. The response acceleration RHe of the structure to be seismically isolated on the floor member 20 is shown.
On the floor member 20 of the structure to be subjected to seismic isolation, a slip occurs between the sliding pad 1 and the sliding plate 2 for an earthquake acceleration He equal to or higher than the acceleration KH determined by the coefficient of friction × gravity acceleration. The response acceleration RHe of the object on the floor member 20 reaches a plateau, and the seismic isolation effect is obtained.

[0004] On the other hand, FIG. 8B is a diagram for explaining the response state of the above-mentioned friction type seismic isolation device to minute vibration such as traffic vibration, and the left side shows acceleration Hv of horizontal minute vibration on the base 5. The right side shows a response acceleration RHv to a minute vibration on the structure 4 to be subjected to seismic isolation. Since the acceleration GV of the minute vibration is equal to or less than the acceleration KH determined by the coefficient of friction × gravity acceleration, no slippage occurs between the sliding pad 2 and the sliding plate 1 and on the floor member 20 of the structure to be seismically isolated. Has the same value as the acceleration Hv of the micro vibration on the base 10.

[0005]

As apparent from the description of FIG. 8B, the conventional friction-type seismic isolation device of the above-described type has a vibration reducing effect against minute vibrations such as traffic vibrations.
That is, it does not have a vibration isolation effect. Therefore, when installing a precision machine such as an electron microscope on a seismic isolation floor or building using the above-mentioned friction type seismic isolation device, a vibration isolation device that reduces minute vibration such as traffic vibration is separately installed. There was a problem in terms of cost and space. On the other hand, as a seismic isolation device having a vibration isolation function, there is a device disclosed in Japanese Patent Application Laid-Open No. 2-47777, which uses a laminated rubber to obtain a horizontal seismic isolation function. However, there is a problem in that the height is higher and the cost is higher. The present invention
In view of the above problems, an object of the present invention is to provide a low-cost, small-space seismic isolation device.

[0006]

According to the first aspect of the present invention, a first friction member connected to an upper surface of a base and a second friction member connected to a lower surface of a structure and frictionally engaged with the first friction member. And a horizontal seismic isolation means for suppressing transmission of horizontal vibration of the base exceeding the friction limit to the structure, and one of the first friction member and the base, or the second friction member and the structure. An anti-vibration means, which is elastically coupled with an elastic body having elasticity capable of attenuating horizontal vibration of a base below a friction limit,
And horizontal displacement restricting means for restricting horizontal displacement of the structure caused by the vibration isolation means when the horizontal seismic isolation means is operated and the horizontal vibration of the friction limit is transmitted to the structure. Provided is a seismic isolation device. In the seismic isolation device having such a configuration, when horizontal vibration of the base exceeding the friction limit occurs, slippage occurs between the first friction member and the second friction member, and the structure has a friction limit higher than the friction limit. No horizontal vibration is transmitted. Here, the structure is displaced in the horizontal direction by the vibration isolator, but the displacement is restricted by the horizontal displacement restricting means. On the other hand, the horizontal vibration of the base below the friction limit is attenuated by the elastic body.

According to a second aspect of the present invention, in the first aspect of the present invention, the elastic coupling fixes the elastic body to the base or structure, and further fixes the supporting member to the fixed elastic body.
The first friction member or the second friction member is fixed to the support member, and the horizontal displacement restricting means includes a pin hole formed in the support member and a length fixed to the base or structure and passing through the pin hole. When the base is stationary, the pin passes through the pin hole through the gap, and when the base makes a minute vibration of a magnitude equal to or greater than a predetermined value, the pin contacts the pin hole, The relative position and radial relative dimension of the pin and the pin hole are determined as described above, and the horizontal displacement is regulated by the pin and the pin hole. According to the invention of claim 3, in the invention of claim 2, both the pin and the pin hole are circular in cross section, and the gap between the pin and the pin hole at rest is several m.
m, and the horizontal displacement is restricted to several mm.

According to a fourth aspect of the present invention, in the second aspect of the present invention, the elastic coupling further fixes the sub-elastic member to the support member, fixes the sub-support member to the sub-elastic member, and fixes the sub-support member to the sub-support member. The first friction member or the second friction member is fixedly attached, and the horizontal displacement restricting means includes a sub-pin hole formed in the sub-support member. The relative position of the pin hole formed in the support member with respect to the pin is the same as the relative dimension in the radial direction. The pin is fixed to the auxiliary elastic body, and the pin cooperates with the two pin holes to displace the horizontal direction. regulate.

According to a fifth aspect of the present invention, in the first aspect of the present invention, there is further provided vertical seismic isolation means for attenuating the vertical vibration of the base transmitted to the structure, which is included in the vibration isolation means. The elastic body has the elasticity to absorb the minute vertical vibration of the base that the vertical seismic isolation means does not attenuate, and the vertical that regulates the vertical displacement of the structure by the vibration isolation means when the vertical seismic isolation means operates A seismic isolation device having directional displacement restricting means is provided. In the seismic isolation device thus configured, the vertical vibration of the base transmitted to the structure by the vertical seismic isolation means is also attenuated, and the structure by the vibration isolation means when the vertical seismic isolation means operates. The vertical displacement of the object is regulated by the vertical displacement regulating means.

According to the invention of claim 6, in the invention of claim 5, the vertical displacement restricting means has a vertical length shorter than the vertical thickness of the elastic body by a predetermined difference,
There is provided a seismic isolation device in which one end is fixed to a base or a structure or a support member and is a stopper embedded in an elastic body. According to the invention of claim 7, the difference between the length of the stopper and the thickness of the elastic body is set to several mm,
Vertical displacement is regulated to several mm. According to the invention of claim 8, in the invention of claim 5, the auxiliary elastic body is further fixed to the support member, the auxiliary support member is fixed to the auxiliary elastic body, and the first friction member or the second friction member is fixed to the auxiliary support member. The member is fixed, elastic coupling is performed, and the vertical displacement restricting means includes a stopper fixed at one end to the supporting member or the sub-supporting member and embedded in the sub-elastic member. The length is shortened by the predetermined difference with respect to the vertical thickness of the auxiliary elastic member, and vertical displacement is regulated by two types of stoppers.

According to a ninth aspect of the present invention, there is provided the seismic isolation device in which the vertical seismic isolation means is an air spring type. According to a tenth aspect of the present invention, there is provided the seismic isolation device of the first aspect, wherein the structure and the second friction member are elastically connected.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a view showing the entire structure of the first embodiment, in which a seismic isolation device 30 according to the present invention is provided between a base 10 as a vibration input source and a floor member 20 of a structure to be seismically isolated. Is interposed. The floor member 20 includes a floor frame 21 supporting a floor panel 23 via supporting legs 22, and various structures are constructed on the floor panel 23. The floor frame 21 is connected to the base 10 by a spring device 40 so that the floor member 20 does not undergo excessive displacement.

FIG. 2 is an enlarged view of the seismic isolation device 30.
The seismic isolation device 30 is composed of one attached to the base 10 and one attached to the floor frame 21, and only the slide plate 31 is attached to the base 10. On the other hand, an elastic body 32 is fixed to the lower surface of the floor frame 21, a support member 33 is fixed to the elastic body 32, a sub elastic body 34 is fixed to the support member 33, and a sub support member 35 is fixed to the sub elastic body 34. The friction pad 36 is fixed to the auxiliary support member 35. If the coefficient of friction between the lower surface of the friction pad 36 and the upper surface of the sliding plate 31 is small, slippage occurs between the lower surface of the friction pad 36 and the upper surface of the sliding plate 31 even with a small earthquake (horizontal vibration). Since the vibration is not transmitted, the friction coefficient is set to be small.

A horizontal displacement restraining pin 37 is further fixed to the lower surface of the floor frame 21 and extends downward through a supporting member 33, a sub-elastic body 34, and a sub-supporting member 35. 31 with a gap therebetween. Although the horizontal displacement restraining pin 37 is in close contact with the auxiliary elastic body 34,
The support member 33 and the sub-support member 35 are formed with a first pin hole 33A and a second pin hole 35A having a diameter larger than the outer diameter of the horizontal displacement restraining pin 37. The member 33 does not contact the sub-support member 35. The radius of the horizontal displacement restraining pin 37 and the first pin hole 33A,
The difference between the radii of the second pin holes 35A is a, and at rest,
A gap a is secured between the horizontal displacement restraining pin 37 and the first pin hole 33A and the second pin hole 35A. The size of a is several mm.

The operation and effect of the seismic isolation device of the first embodiment will be described below with reference to FIG. (A) of FIG. 3 is an explanatory diagram of the horizontal seismic isolation effect at the time of an earthquake,
The left side shows the acceleration He in the horizontal direction of the earthquake on the base 10, and the right side shows the response acceleration RHe on the floor panel 23. In FIG. 3A, the response acceleration RHe on the floor panel 23 is the slip pad 36 and the slide plate for an acceleration He equal to or greater than the acceleration KH determined by the coefficient of friction × gravity acceleration as in FIG. 31 between the floor panels 23
Although the response acceleration RHe above reaches a peak, it vibrates between the gap a between the support member 33 and the sub-support member 35 and the horizontal displacement restraining pin 37, so that the response acceleration RHe on the floor panel 23 Has a slight vibration component dRHe superimposed. However, by appropriately setting the gap a, the value of the vibration component dRHe becomes sufficiently small, and does not significantly affect the seismic isolation performance.

FIG. 3B is an explanatory diagram of the vibration isolation effect with respect to the horizontal minute vibration. The left side shows the acceleration Ht of the minute vibration on the base 10, and the right side shows the response to the minute vibration on the floor panel 23. This shows the acceleration RHt. As shown in FIG. 3B, the elastic body 32 and the sub-elastic body 35 provide an anti-vibration effect with respect to the acceleration Ht of the minute vibration, and the response acceleration RHt on the floor panel 23 is the input side acceleration Ht. Has been reduced.

FIG. 3C is an explanatory view of a horizontal seismic isolation effect at the time of an earthquake when the horizontal displacement restraining pin 37 is not provided.
The left side shows the seismic acceleration He on the base 10, and the right side shows the response acceleration RHe on the floor panel 23. When the horizontal displacement restraint pin 37 is not provided, the component mRHe due to the vibration of the sliding pad 36 increases, and the response acceleration RHe on the floor panel 23 is not sufficiently reduced, thereby impeding the original horizontal seismic isolation effect. As described above, in the first embodiment, the displacement of the sliding pad 36 is limited to the appropriate range of the gap a by the horizontal displacement restraining pin 37, so that the horizontal seismic isolation performance is not hindered. An anti-vibration effect can be exhibited even for a minute vibration.

Next, a second embodiment will be described.
FIG. 4 is a view showing the overall structure of the second embodiment, in which a seismic isolation device 50 is interposed between the base 10 and the floor member 20 as in the first embodiment. The floor member 20 includes a floor frame 21 supporting a floor panel 23 via supporting legs 22, and various structures are constructed on the floor panel 23. The floor frame 21 is connected to the base 10 by a spring device 40 so that the floor member 20 does not undergo excessive displacement.

FIG. 5 is an enlarged view of the seismic isolation device 50.
The seismic isolation device 50 is composed of one attached to the base 10 and one attached to the floor frame 21, and only the slide plate 51 is attached to the base 10. On the other hand, on the lower surface of the floor frame 21, first, a vertical seismic isolation device 60 including an air spring or an air cylinder is attached. As in the first embodiment, an elastic body 52 is fixed to the bottom of the vertical seismic isolation device 60, a support member 53 is fixed to the elastic body 52, and a sub elastic body 54 is fixed to the support member 53.
Are fixed, the sub support member 55 is fixed to the sub elastic body 54, and the friction pad 56 is fixed to the sub support member 55. The coefficient of friction between the lower surface of the friction pad 56 and the upper surface of the slide plate 51 is set to be small.

A horizontal displacement restraining pin 57 is fixed to the lower surface of the floor frame 51 in the same manner as in the first embodiment, and extends downward through the support member 53, the sub-elastic body 54, and the sub-support member 55. , The tip of which faces the sliding plate 51 via a gap. The relationship between the horizontal displacement restraining pin 57 and the support member 53, the sub-elastic body 54, and the sub-support member 55 is the same as that of the first embodiment. , The support member 53 and the sub-support member 55
A first pin hole 53A and a second pin hole 55A having a diameter larger than the outer diameter of the horizontal displacement restraint pin 57 are formed, and the horizontal displacement restraint pin 57 does not contact the support member 53 and the sub-support member 55 when stationary. . The radius of the horizontal displacement restraining pin 57 and the first
The difference between the radius of the pin hole 53A and the radius of the second pin hole 55A is a.
A gap a is secured between 3A and the second pin hole 55A. The size of a is several mm as in the first embodiment.

Unlike the first embodiment, the vertical displacement restraining pins 58, 5
9 are arranged. The vertical displacement restraining pin 58 extends downward from the lower surface of the vertical seismic isolation device 60, and the tip thereof is
Ends with a distance b from the upper surface of the vertical displacement restraining pin 59.
Extends upward from the upper surface of the support member 53 toward the vertical seismic isolation device 60, and the tip ends at a distance b from the lower surface of the vertical seismic isolation device 60. The size of b is several mm.

In the second embodiment, the horizontal vibration isolation and vibration isolation effect is the same as that of the first embodiment. Therefore, the vertical vibration isolation and vibration isolation effects will be described. FIG. 6A is an explanatory diagram of the vertical seismic isolation effect of the earthquake. The left side shows the vertical acceleration Ve on the base 10, and the right side shows the vertical response acceleration RVe on the floor panel 23. Show. In FIG. 6A, the vertical response acceleration RVe on the floor panel 23 is reduced by the vertical seismic isolation device 25 in terms of high-frequency components and becomes smaller than the acceleration Ve of the base 10, but the friction pad 56 Since vibration occurs at the distance b between the tip of the vertical displacement restraint pin 58 and the support member 53 and between the vertical displacement restraint pin 59 and the lower surface of the vertical seismic isolation device 60, the response acceleration RVe on the floor panel 23 is Slight vibration component d
A response in which RVe is superimposed. However, by appropriately setting the distance b, the value of the vibration component dRVe becomes sufficiently small, and does not significantly affect the seismic isolation performance.

FIG. 6B is an explanatory diagram of the vibration isolation effect with respect to the vertical minute vibration. The left side shows the acceleration Vt of the vertical minute vibration on the base 10, and the right side shows the acceleration Vt on the floor panel 23. The vertical direction response acceleration RVt to the micro vibration is shown. As shown in the drawing, a vibration isolation effect is obtained even for the vertical minute vibration Vt, and the vertical response acceleration RVt on the floor panel 23 is reduced.

FIG. 6C shows vertical displacement restraining pins 58 and 5.
9 is an explanatory diagram of the vertical seismic isolation effect when there is no 9, the left side represents the vertical acceleration Ve of the earthquake on the base 10,
The right side is the vertical response acceleration RVe on the floor panel 23.
Is shown. As shown in the figure, the component mRVe due to the vibration of the sliding pad 52 increases, and the response acceleration RVe on the floor panel 23 is not sufficiently reduced, thereby impairing the original seismic isolation effect. As described above, according to the seismic isolation device of the second embodiment, the horizontal displacement restraint pin 57 and the vertical displacement restraint pin 5
8 and 59, the displacement of the friction pad 56 is limited to an appropriate range of the horizontal gap a and the vertical gap b, thereby eliminating horizontal and vertical minute vibrations without impairing horizontal and vertical seismic isolation performance. It is possible to exhibit a vibration effect.

[0025]

The seismic isolation device according to the present invention has a first friction member coupled to the upper surface of the base and a first friction member coupled to the lower surface of the structure and frictionally engaged with the first friction member. (2) any one of a horizontal seismic isolation means including a friction member and suppressing transmission of horizontal vibration of a base exceeding a friction limit to a structure, a first friction member and a base, or a second friction member and a structure One of which is elastically coupled with an elastic body having elasticity capable of attenuating horizontal vibration of the base below the friction limit,
And horizontal displacement restricting means for restricting horizontal displacement of the structure caused by the vibration isolation means when the horizontal seismic isolation means is operated and the horizontal vibration of the friction limit is transmitted to the structure. If the horizontal vibration of the base is higher than the friction limit, a slip occurs between the first friction member and the second friction member, and the horizontal vibration higher than the friction limit is not transmitted to the structure. Here, the structure is displaced in the horizontal direction by the vibration isolator, but the displacement is restricted by the horizontal displacement restricting means. on the other hand,
The horizontal vibration of the base below the friction limit is attenuated by the elastic body. In particular, according to the second aspect, the horizontal displacement is regulated by the pin and the pin hole.

The seismic isolation device according to the fifth aspect of the present invention further includes vertical seismic isolation means for attenuating the vertical vibration of the base transmitted to the structure, and the elasticity included in the vibration isolation means. The vertical direction in which the body has elasticity to absorb the minute vertical vibration of the base that the vertical seismic isolation means does not attenuate, and restricts the vertical displacement of the structure by the vibration isolation means when the vertical seismic isolation means operates Vertical displacement of the base transmitted to the structure by the vertical seismic isolation means is also attenuated,
When the vertical seismic isolation means operates, the vertical displacement of the structure by the vibration isolation means is regulated by the vertical displacement regulation means. In particular, according to claim 6, the stopper is embedded in the elastic body in the vertical direction. Is restricted.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a seismic isolation device of a first embodiment.

FIG. 2 is an enlarged view of the seismic isolation device of FIG.

FIG. 3A is an explanatory diagram of a horizontal seismic isolation effect of the seismic isolation device of FIG. 1; (B) is an explanatory view of the horizontal vibration isolation effect of the seismic isolation device of FIG. 1. (C) is an explanatory view of a horizontal seismic isolation effect (no effect) when the horizontal displacement restraint pin is removed by the seismic isolation device of FIG. 1.

FIG. 4 is a diagram illustrating a seismic isolation device according to a second embodiment.

FIG. 5 is an enlarged view of the seismic isolation device of FIG.

6A is an explanatory diagram of a vertical seismic isolation effect of the seismic isolation device of FIG. 4; FIG. (B) is an explanatory view of a vertical vibration isolation effect of the seismic isolation device of FIG. 4. (C) is an explanatory view of a vertical seismic isolation effect (no effect) when the vertical displacement restraint pin is removed by the seismic isolation device of FIG. 4.

FIG. 7 is a diagram showing the structure of a friction type seismic isolation device of the related art.

FIG. 8A is an explanatory diagram of a seismic isolation effect of the seismic isolation device of FIG. 7; (B) shows the vibration isolation effect of the seismic isolation device in Fig. 7 (no effect)
FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Base 20 ... Floor member (of the structure to be seismically isolated) 30 ... Seismic isolation device (1st Embodiment) 31 ... Sliding plate 32 ... Elastic body 33 ... Support member 33A ... 1st pin hole 34 ... Sub Elastic member 35 ... Sub-support member 35A ... Second pin hole 36 ... Friction pad 37 ... Horizontal displacement restraining pin 40 ... Over-displacement prevention member 50 ... Seismic isolation device (Second embodiment) 51 ... Sliding plate 52 ... Elasticity Body 53: Support member 53A: First pin hole 54: Secondary elastic member 55: Secondary support member 55A: Second pin hole 56: Friction pad 57: Horizontal displacement restraint pin 58, 59 ... Horizontal displacement restraint pin 60: Vertical seismic isolation apparatus

Claims (10)

[Claims] 1. A horizontal vibration of a base, which includes a first friction member coupled to an upper surface of a base and a second friction member coupled to a lower surface of a structure and frictionally engages with the first friction member, wherein the horizontal friction exceeds a friction limit. Horizontal seismic isolation means that suppresses transmission to the structure, and either one of the first friction surface and the base or the second friction surface and the structure attenuates horizontal vibration of the base below the friction limit. Vibration isolation means, which is elastically coupled by an elastic body having elasticity, and a structure caused by the vibration isolation means when the horizontal vibration of friction limit is transmitted to the structure by operating the horizontal seismic isolation means And a horizontal displacement restricting means for restricting horizontal displacement of the seismic isolation device. 2. An elastic joint for fixing an elastic body to a base or a structure, further fixing a support member to the fixed elastic body, and fixing a first friction member or a second friction member to the support member. The horizontal displacement restricting means comprises a pin hole formed in the support member and a pin fixed to the base or structure and having a length passing through the pin hole, and when the ground is stationary, the pin is The relative position and radial dimension of the pin and the pin hole are determined so that the pin contacts the pin hole when the pin passes through the pin hole through the gap and the ground vibrates slightly more than a predetermined value. 2. The seismic isolation structure according to claim 1, wherein: 3. The seismic isolation device according to claim 2, wherein both the pin and the pin hole are circular in cross section, and a gap between the pin and the pin hole at rest is several mm. 4. The elastic coupling further comprises fixing a sub-elastic member to the support member, fixing the sub-support member to the sub-elastic member, and fixing the first friction member or the second friction member to the sub-support member. The horizontal displacement restricting means includes a sub-pin hole formed in the sub-support member, the relative position of the sub-pin hole with respect to the pin, the relative radial dimension is the relative position of the pin hole formed in the support member with respect to the pin, The seismic isolation device according to claim 2, wherein the pin has the same dimension as the relative dimension in the radial direction, and the pin is fixed to the secondary elastic body. 5. The base further comprises vertical seismic isolation means for attenuating the vertical vibration of the base transmitted to the structure, wherein the elastic body included in the vibration isolation means is a microscopic part of the base on which the vertical seismic isolation means is not attenuated. Vertical displacement restricting means for restricting vertical displacement of the structure by the vibration isolation means when the vertical seismic isolation means is activated. Item 4. The seismic isolation device according to Item 1. 6. The vertical displacement restricting means has a vertical length shorter than a vertical thickness of the elastic body by a predetermined difference, and one end is fixed to a base or a structure, or a support member. The seismic isolation device according to claim 5, wherein the stopper is a stopper embedded in the elastic body. 7. The difference between the length of the stopper and the thickness of the elastic body,
The seismic isolation device according to claim 6, wherein the distance is set to several mm. 8. An auxiliary elastic body is further fixed to the support member,
The auxiliary support member is fixed to the auxiliary elastic member, and the first friction member or the second friction member is fixed to the auxiliary support member to perform elastic coupling. The vertical displacement restricting means includes a support member or an auxiliary support member. A stopper fixed at one end to the auxiliary elastic member, the vertical length of the stopper also being shorter than the vertical thickness of the auxiliary elastic member by the predetermined difference. Item 7. The seismic isolation device according to Item 6. 9. The seismic isolation device according to claim 5, wherein the vertical seismic isolation means is an air spring type. 10. The vibration isolation device according to claim 1, wherein the structure and the second friction member are elastically connected.