Friction joint structure

Abstract

To provide a friction joint structure capable of enhancing vibration energy absorption performance by increasing frictional resistance after sliding while preventing an increase in frictional resistance before sliding.SOLUTION: A friction joint structure comprises a driving plate, a driven plate, an intermediary member, a bolt inserted into first and second through-holes, a nut screwed to the bolt, and a joint member which has a pair of washers with the bolt penetrating therethrough and introduces fastening force to a laminated body formed with the driving plate, the driven plate and the intermediary member through the pair of washers. The intermediary member has a guide section allowing the bolt to move. When planar force acts to separate the driving plate from the intermediary member, the bolt moves along the guide section, causing the driving plate to be guided in the acting direction of the planar force while remaining in planar contact with the intermediary member. The first and second through-holes have a diameter larger than a diameter of a bolt axial section. As the driving plate moves in the acting direction of the planar force, the driven plate also begins to move in the acting direction.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a friction joint structure, and more particularly to a friction joint structure capable of improving the performance of absorbing vibration energy generated by an earthquake or the like. [Background technology]

[0002] Conventionally, vibration-damping structures are used in bridges, tunnels, high-rise buildings, etc. to absorb vibration energy from earthquakes and the like. In a vibration-damping structure, for example, two members that generate friction are stacked one above the other, and vibration energy is absorbed by utilizing the frictional resistance force that occurs when one of the members shifts (slides) horizontally relative to the other member. In addition to increasing the frictional resistance force, increasing the axial force from the vertical direction by using bolt joints is also an effective method for absorbing vibration energy. (See Patent Documents 1 and 2).

[0003] For example, Patent Document 1 discloses a vibration-damping structure for a bolt joint that effectively damps vibrations in a building frame. This vibration-damping structure overlaps two press-welded plates incorporated in a steel frame member, and allows relative movement between the two press-welded plates to apply bolt axial force, so that vibration between the two steel frame members is damped by the frictional resistance force generated between the two press-welded plates. A pair of friction plates and sliding plates are sandwiched between the first press-welded plate and the second press-welded plate, and the bolt joint has a seven-layer structure. With this configuration, it is possible to generate a nearly constant frictional resistance force at all times, and obtain a stable vibration-damping effect.

[0004] Patent Document 2 discloses a high-strength bolt friction joint structure that can be used as a vibration-damping structure to achieve strong joints even with a small number of bolts. This high-strength bolt friction joint structure is formed by joining a pair of steel materials, and at the ends of the pair of steel materials on the joining side, at least two plate-shaped ends are arranged to overlap, and the plate-shaped end of one steel material and the plate-shaped end of the other steel material are laminated and pressed together by a high-strength bolt. This configuration that can increase the friction surface allows for strong joints even with a small number of bolts. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2000-352113 A [Patent Document 2] JP 2019-60409 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the above patent documents, the frictional resistance force generated between two members is used to absorb vibration energy. When the frictional resistance force after slippage between two members is increased, the frictional resistance force before slippage also increases. Specifically, when the maximum static friction force before slippage is increased by F fmax , the kinetic friction force after sliding is F fkin Let μ be the static friction coefficient, μ' be the dynamic friction coefficient, m be the number of friction surfaces (m=1 in this structure), n be the number of bolts, N be the bolt axial force just before the slip, and N' be the bolt axial force after the slip. F fmax = μ m n N (1) F fkin = μ' m n N' (2) This can be expressed as:

[0007] In general, the relationship between the static friction coefficient μ and the dynamic friction coefficient μ' of a material is μ>μ', and in addition, the axial force N of the high-strength bolt used in a high-strength bolt friction joint tends to decrease significantly (N>N') when slippage occurs. In other words, F fmax >F fkin However, F fkin The smaller the F becomes, the lower the energy absorption performance becomes. On the other hand, if the number of bolts is increased to ensure a certain energy absorption performance, the F fkin Not only that, F fmax Also increases. F fmaxWhen the device shown in Patent Document 1 is installed, for example, if F fmax However, this required the placement of fixing devices (generally anchor bolts, etc.) on the bridge piers that could withstand such loads, resulting in inconveniences such as a lack of installation space and increased load on the bridge piers.

[0008] Therefore, an object of the present invention is to provide a friction joining structure that can improve the vibration energy absorption performance by suppressing the increase in friction resistance force before slippage while increasing the friction resistance force after slippage. [Means for solving the problem]

[0009] In response to the above-mentioned problems, the present invention provides a friction joint structure in which relative movement between stacked members is suppressed by frictional resistance force generated by surface contact between the stacked members, the friction joint structure comprising a flat driving plate having a first through hole formed in the plate thickness direction, a flat driven plate having a second through hole formed in the plate thickness direction, a flat intermediate member disposed between the driving plate and the driven plate, a bolt inserted into the first through hole and the second through hole, a nut screwed onto the bolt, and a pair of washers through which the bolt is inserted, and the friction joint structure is configured to be joined by the driving plate, the driven plate, and the intermediate member. and a connecting member that introduces a fastening force via the pair of washers into a laminate configured as above, the intermediate member is formed with a guide portion along which the bolt can move, and when a force in a planar direction acts to separate the main driving plate from the intermediate member, the main driving plate is guided in an acting direction while being in planar contact with the intermediate member as the bolt moves along the guide portion, the first through hole and the second through hole both have a diameter larger than the shaft portion of the bolt, and as the main driving plate moves in the acting direction, movement of the driven plate in the acting direction begins. Effect of the Invention

[0010] According to the present invention, the above-mentioned configuration makes it possible to improve the vibration energy absorption performance by increasing the frictional resistance force after slippage while suppressing an increase in the frictional resistance force before slippage. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1A is a perspective view for explaining a friction joining structure according to an embodiment of the present invention, and FIG. [Diagram 2] 1A is a plan view of the drive plate, and FIG. 1B is a side view of the drive plate. [Diagram 3] 1A is a plan view of the driven plate, and FIG. 1B is a side view of the driven plate. [Figure 4] 1A is a plan view of the intermediate member, and FIG. 1B is a side view of the intermediate member. [Diagram 5] 2A is a cross-sectional view taken along the line AA in FIG. 1, FIG. 2B is a diagram showing the relationship between a first through hole and the shaft portion, and FIG. 2C is a diagram showing the relationship between a second through hole and the shaft portion. [Figure 6] 13 is a diagram showing an example in which a buffer material is provided inside a first through hole and a second through hole. FIG. [Figure 7] 1(a) is a diagram of the friction joint structure in the initial state, and FIG. 1(b) is a cross-sectional view taken along the line B--B. [Figure 8] This is a graph of the initial state. [Figure 9] (a) is a diagram of the friction joint structure at the initial slip, and (b) is its CC cross-sectional view. [Figure 10] This is a graph showing the initial slip. [Figure 11] 1(a) is a diagram of the friction joint structure at the beginning of the movement of the driven plate, and FIG. 1(b) is a DD cross-sectional view of the same. [Figure 12] 13 is a graph showing the initial movement of a driven plate. [Figure 13] (a) is a diagram of the friction joint structure at the time of final slip, and (b) is its E-E cross-sectional view. [Figure 14] This is a graph of the final slide. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0013] Fig. 1(a) is a perspective view for explaining a friction welding structure 1 according to this embodiment, and Fig. 1(b) is a side view thereof. The friction welding structure 1 has a structure in which, when an external force is applied, the relative movement between the members is suppressed by the friction resistance force generated between the members stacked in surface contact, and when vibration is applied to the friction welding structure 1, the vibration energy is absorbed by the friction resistance force between the members.

[0014] The friction joint structure 1 is configured to include a driving plate 10, a driven plate 20, an intermediate member 30, and a connecting member 40. The driving plate 10, the intermediate member 30, and the driven plate 20 are stacked in this order, with the driving plate 10 disposed above the intermediate member 30 in a surface-contact state, and the driven plate 20 disposed below the intermediate member 30 in a surface-contact state. In the following description, an example will be described in which the driving plate 10 is located above the driven plate 20, but this is for convenience of description, and the driven plate 20 may be located above the driving plate 10. The driving plate 10, the driven plate 20, and the intermediate member 30 form a laminate L.

[0015] The driving plate 10, the driven plate 20 and the intermediate member 30 are all flat plate-like members formed in a generally rectangular shape in a plan view, and the driving plate 10 and the intermediate member 30 are formed to have approximately the same shape and dimensions. The driven plate 20 is formed to have a shorter dimension in the width direction than the driving plate 10 and the intermediate member 30. The dimensions of the driving plate 10, the driven plate 20 and the intermediate member 30 may be different from each other, or may all be formed to have the same dimensions. In the following description, the longitudinal direction of the driving plate 10, the driven plate 20 and the intermediate member 30 is defined as the X direction, the lateral direction is defined as the Y direction, and the stacking direction is defined as the Z direction.

[0016] As shown in Fig. 1(a), the connecting members 40 are arranged in 3 rows and 2 columns. Specifically, two rows of three connecting members 40 arranged along the longitudinal direction (X direction) are arranged in the lateral direction (Y direction). The three connecting members 40 arranged along the longitudinal direction are arranged at equal intervals. The positions and number of connecting members 40 are not particularly limited.

[0017] 1(b), each joining member 40 has a bolt 41 that penetrates the laminate L, a nut 42 that is screwed onto the bolt 41, and a pair of washers 43 through which the bolt 41 is inserted. The joining members 40 join the laminate L from above and below, and a fastening force (axial force) is applied to the laminate L in the axial direction of the bolt 41.

[0018] Fig. 2(a) is a plan view of the drive plate 10, and Fig. 2(b) is a side view thereof. The drive plate 10 is a plate-like member formed in a generally rectangular shape in a plan view. One end of the drive plate 10 in the longitudinal direction is a first end 10a, and the other end is a second end 10b.

[0019] The driving plate 10 is formed with a plurality of first through holes 11 penetrating in the plate thickness direction. Each of the first through holes 11 has the same size and shape, and is formed in a circular shape in a plan view. The first through holes 11 may have any size and shape as long as the bolt 41 can pass through them. Of the plurality of first through holes 11, some of the first through holes 11 do not need to be penetrated by the bolt 41. The inner surface of each of the first through holes 11 is defined as a first inner peripheral surface 11a.

[0020] As shown in FIG. 2(a), three first through holes 11 are formed along the longitudinal direction, two first through holes 11 are formed along the lateral direction, and six first through holes 11 are arranged in three rows and two columns. Specifically, a first through hole group is made up of a plurality (three) of first through holes 11 formed in a row along the longitudinal direction (X direction), and this first through hole group is arranged in two rows along the longitudinal direction. The first through holes 11 formed in a row along the longitudinal direction are arranged at equal intervals. The first through holes 11 (first through hole group) extend parallel to each other along the longitudinal direction, and are all arranged closer to the second end 10b than the center part in the longitudinal direction.

[0021] The number of the first through holes 11 formed in the driving plate 10 may be only one, not multiple. The number of the first through holes 11 constituting the first through hole group may be other than three, and the number of the first through hole groups provided may be other than two rows. The number of the first through holes 11 formed is not particularly limited, but the more the number of the first through holes 11 formed in the driving plate 10, the more the number of the connecting members 40 that can be passed through can be increased, and the fastening force applied by the connecting members 40 can be increased. In addition, by forming the first through holes 11 in two rows along the longitudinal direction, the direction of movement of the connecting members 40 can be regulated (guided) only in the longitudinal direction.

[0022] The surface of the upper side (opposite the intermediate member 30) of the drive plate 10 is a first non-contact surface 12, and the surface of the lower side (the intermediate member 30 side) is a first contact surface 13. The first contact surface 13 is a surface that comes into surface contact with the intermediate member 30, and when the drive plate 10 moves away from the intermediate member 30, it functions as a friction force applying surface that generates frictional resistance between the drive plate 10 and the intermediate member 30.

[0023] The drive plate 10 may be made of a material having a high coefficient of friction, such as a metal such as a steel plate, reinforced plastic, etc. The drive plate 10 may be made of any material as long as it generates frictional resistance between the drive plate 10 and the intermediate member 30.

[0024] Fig. 3(a) is a plan view of the driven plate 20, and Fig. 3(b) is a side view thereof. The driven plate 20 is a plate-like member formed in a generally rectangular shape in plan view, similar to the driven plate 10, and is formed to have a smaller dimension in the width direction (short side direction) than the driven plate 10. The driven plate 20 is formed in substantially the same manner as the driven plate 10, and therefore a detailed description will be omitted as appropriate. One end of the driven plate 20 in the longitudinal direction is a third end 20a, and the other end is a fourth end 20b.

[0025] The driven plate 20 is formed with a plurality of second through holes 21 penetrating in the plate thickness direction. Each of the second through holes 21 is formed at a position that coincides with the first through hole 11 in a plan view. Specifically, a plurality (three) of second through holes 21 formed in a row along the longitudinal direction (X direction) constitute a second through hole group, and each of the second through holes 21 constituting this second through hole group is formed at a position that can penetrate the first through hole 11 in the stacking direction (vertical direction) of the laminate L. The second through hole 21 is formed in a circular shape in a plan view, but may have any size and shape as long as the bolt 41 can penetrate through it. The second through hole 21 is formed to have a larger diameter than the first through hole 11. Since the second through hole 21 is formed at a position that coincides with the first through hole 11 in the vertical direction, if the first through hole 11 formed in the driven plate 10 is formed at one place, the second through hole 21 may also be formed at only one place. The inner surface of each of the second through holes 21 is defined as a second inner circumferential surface 21a.

[0026] The surface on the upper side (the intermediate member 30 side) of the driven plate 20 is a second contact surface 22, and the surface on the lower side (the side opposite to the intermediate member 30) is a second non-contact surface 23. The second contact surface 22 is a surface that comes into surface contact with the intermediate member 30, and when the driven plate 20 moves away from the intermediate member 30, it functions as a friction force applying surface that generates friction resistance between the driven plate 20 and the intermediate member 30. The static friction coefficient of the second contact surface 22 may be the same as or different from the static friction coefficient of the first contact surface 13.

[0027] The driven plate 20 may be made of any material having a high coefficient of friction, such as a metal such as a steel plate or a reinforced plastic, which is different from the material of the washer 43. The driven plate 20 may be made of any material as long as it generates friction between the driven plate 20 and the intermediate member 30.

[0028] Fig. 4(a) is a plan view of the intermediate member 30, and Fig. 4(b) is a side view thereof. The intermediate member 30 is a plate-like member formed in a generally rectangular shape in a plan view. One end of the intermediate member 30 in the longitudinal direction is a fifth end 30a, and the other end is a sixth end 30b.

[0029] As shown in FIG. 4(a) and FIG. 4(b), the intermediate member 30 has a guide portion 31 formed along the longitudinal direction. That is, the guide portion 31 is configured with a pair of slits 31a with the sixth end portion 30b side open, and the pair of slits 31a extend parallel to each other along the longitudinal direction. The number of slits constituting the guide portion 31 may be three or more, and the multiple slits may be separated or may be integrally formed in a connected state. The guide portion 31 may have any shape as long as it has a portion that extends linearly along the longitudinal direction, and may be configured with a shape other than a slit, for example, a long hole. The length of the guide portion 31 along the longitudinal direction is not particularly limited, but it is desirable that it is as long as possible from the viewpoint of providing a frictional resistance force for a long time as described later.

[0030] Each guide portion 31 coincides with the plurality of first through holes 11 (first through hole group) and the plurality of second through holes 21 (second through hole group) in the stacking direction. The plurality of first through holes 11, the guide portion 31, and the second through hole 21 coincide in the stacking direction (Z direction), so that the bolt 41 can penetrate the stack L. The bolt 41 can move only along the direction in which the guide portion 31 extends. Therefore, when an external force such as a tensile force or a fastening force acts on the driven plate 10 with the bolt 41 inserted into the guide portion 31, the driven plate 10 also moves in the moving direction of the bolt 41, that is, along the extending direction of the guide portion 31, regardless of the direction of the acting force (hereinafter simply referred to as the "acting direction"). This allows the driven plate 10 or the driven plate 20 to continue to move linearly relative to the intermediate member 30. Furthermore, since a pair of slits 31a is formed along the longitudinal direction, the moving direction of the connecting member 40 can be limited to only the longitudinal direction.

[0031] The surface of the intermediate member 30 on the upper side (the driving plate 10 side) is a first sliding contact surface 32, and the surface on the lower side (the driven plate 20 side) is a second sliding contact surface 33.

[0032] Fig. 5(a) is a cross-sectional view seen in the direction of the arrow AA in Fig. 1. As shown in Fig. 5, the driving plate 10, the intermediate member 30, and the driven plate 20 are stacked vertically in this order, and are integrated by a bolt 41, a nut 42, and a pair of washers 43. Of the pair of washers 43, the upper washer 43 is in contact with the first non-contact surface 12, and the lower washer 43 is in contact with the second non-contact surface 23.

[0033] In the integrated state, the connecting member 40 connects the laminate L from above and below with a pair of washers 43. This increases the frictional resistance force generated between the first sliding contact surface 32 and the first contact surface 13, and between the second sliding contact surface 33 and the second contact surface 22. In addition, in the integrated state, the shaft portion 41a of the bolt 41 is disposed in a state spaced apart from all of the driving plate 10, the driven plate 20, and the intermediate member 30. In other words, the shaft portion 41a is disposed in a state spaced apart from all of the first inner circumferential surface 11a, the second inner circumferential surface 21a, and the guide portion 31.

[0034] 5(b) is a diagram showing the relationship between the first through hole 11 and the shaft portion 41a. The shaft portion 41a is located approximately at the center of the first through hole 11 in the radial direction, and a first gap G1 is formed between the bolt 41 and the first inner circumferential surface 11a. This is because, assuming that the diameter of the shaft portion 41a is D0 and the diameter of the first through hole 11 is D1, D1 is formed to be larger than D0. Due to the formation of the first gap G1, when an external force such as a tensile force acts on the driving plate 10, the bolt 41 can move in the acting direction by the distance of the first gap G1.

[0035] FIG. 5(c) is a diagram showing the relationship between the second through hole 21 and the shaft portion 41a. The shaft portion 41a is located at approximately the center of the second through hole 21 in the radial direction, and a second gap G2 is formed between the bolt 41 and the second inner circumferential surface 21a. This is because, assuming that the diameter of the shaft portion 41a is D0 and the diameter of the second through hole 21 is D2, D2 is formed to be larger than D0. In addition, since D2 is larger than D1, the diameter of the second gap G2 is larger than the first gap G1. Therefore, the movable distance of the shaft portion 41a in the second through hole 21 is larger than the movable distance of the shaft portion 41a in the first through hole 11.

[0036] Fig. 6 is a diagram showing an example in which a buffer material 50 is provided inside the first through hole 11 and the second through hole 21. As shown in Fig. 6, the buffer material 50 is provided in the first gap G1 and the second gap G2. A gap may be provided between the buffer material 50 and the first inner circumferential surface 11a or the second inner circumferential surface 21a. Examples of the buffer material 50 include elastic materials such as rubber and sponge.

[0037] A vibration suppression mechanism when vibration occurs in the friction joint structure 1 according to this embodiment will be described. In actual use, it is considered that a force acts on both the driven plate 10 and the driven plate 20 to separate them from the intermediate member 30. However, for the sake of convenience, the following description will be given with an example of a case where a force acts only on the driven plate 10. In addition, the intermediate member 30 is assumed to be fixed to a structure (not shown). Furthermore, there are various possible cases where a force acts on the driven plate 10, such as not only a case where the driven plate 10 moves in the horizontal direction relative to the driven plate 10, but also a case where a force acts in a direction other than the horizontal direction. However, for the sake of simplicity, the following description will be given with an example of a tensile force acting on the driven plate 10, and the direction in which the tensile force occurs (the acting direction) is the surface direction of the driven plate 10, particularly the longitudinal direction (X direction).

[0038] Fig. 7(a) is a diagram showing a static state (initial state) before vibration occurs in the friction joint structure 1 or immediately after vibration occurs, and Fig. 7(b) is a B-B cross-sectional view thereof. In Fig. 7(b), the outline arrow indicates the direction in which a tensile force acts, the filled arrow indicates the direction in which a fastening force (axial force) by the joining member 40 acts, and the dashed arrow indicates the direction in which a static friction force occurs between the first sliding contact surface 32 and the first contact surface 13 acts. The direction in which the tensile force acts may be either left or right in the horizontal direction, but the following description will be given assuming that the tensile force acts on the right side of the page.

[0039] In the initial state, the intermediate member 30 is disposed between the driving plate 10 and the driven plate 20. In addition, the second end 10b, the fourth end 20b, and the sixth end 30b are aligned in the operating direction. The bolt 41 is inserted into the first through hole 11, the second through hole 21, and the guide portion 31, and a first gap G1 is formed between the shaft portion 41a and the first inner peripheral surface 11a, and a second gap G2 is formed between the shaft portion 41a and the second inner peripheral surface 21a. The positional relationship between the bolt 41, the first through hole 11, the guide portion 31, and the second through hole 21 shown in FIG. 7(b) applies to all of the connecting members 40.

[0040] When a tensile force acts on the drive plate 10, the drive plate 10 is encouraged to move in the direction in which the tensile force acts (direction of action). Meanwhile, a static friction force acts between the first contact surface 13 of the drive plate 10 and the first sliding surface 32 of the intermediate member 30, and a force that prevents the drive plate 10 from moving in the direction of action acts. Furthermore, a fastening force (axial force) is applied from above and below by the connecting member 40 to the laminate L, and this axial force prevents the drive plate 10, the driven plate 20, and the intermediate member 30 from moving in the horizontal direction.

[0041] The initial state is a state in which the tensile force acting on the drive plate 10 is gradually increased, but the drive plate 10 does not move relative to the intermediate member 30. This is because the resultant force of the static friction force and the axial force is greater than the tensile force, so the drive plate 10 does not slip relative to the intermediate member 30. The initial state continues until just before the drive plate 10 starts to move in the acting direction.

[0042] FIG. 8 is a schematic graph for explaining the relationship between the load (tensile force) and the displacement when a tensile force is applied to the friction joint structure 1. In FIG. 8, the vertical axis is the value of the load (N) acting on the friction joint structure 1, and the horizontal axis is the amount of displacement (mm) occurring in the friction joint structure 1. In FIG. 8, the solid line portion corresponds to the initial state. As shown in FIG. 8, when the tensile force is gradually increased in the direction (surface direction) in which the driving plate 10 is separated from the intermediate member 30, the driving plate 10 continues to deform due to internal strain until a certain load or more is applied while resisting the tensile force. Specifically, as shown in FIG. 8, for a certain period from when the tensile force starts to act, the amount of deformation of the driving plate 10 also increases with the increase in the tensile force until the tensile force reaches a critical value P0.

[0043] Fig. 9(a) is a diagram showing a state immediately after the driving plate 10 starts to slide in the acting direction (initial sliding state), and Fig. 9(b) is its CC cross-sectional view. In Fig. 9(b), the white arrow indicates the direction in which the tensile force acts, the black arrow indicates the direction in which the fastening force (axial force) of the connecting member 40 acts, and the hatched arrow indicates the direction in which the kinetic friction force generated between the first sliding contact surface 32 and the first contact surface 13 acts.

[0044] During the initial slip, only the driving plate 10 starts to move in the acting direction relative to the intermediate member 30, and the driven plate 20 and the intermediate member 30 are maintained in a stationary state. This is because the tensile force acting on the driving plate 10 increases and exceeds the resultant force of the static friction force and the axial force. When the driving plate 10 starts to slide in the acting direction, the force acting between the first contact surface 13 and the first sliding surface 32 changes from a static friction force to a kinetic friction force. In general, since the kinetic friction force is smaller than the static friction force, when the driving plate 10 starts to slide, the load is temporarily significantly reduced, and after the load is reduced, the load is maintained at a low state. During the initial slip, the driven plate 20 is maintained in a stationary state, so a second gap G2 is secured between the shaft portion 41a and the second inner peripheral surface 21a.

[0045] Here, in the previous initial state, a first gap G1 was formed between the shaft portion 41a and the first inner circumferential surface 11a. During initial slip, the driven plate 10 moves by the first gap G1, the shaft portion 41a comes into contact with the first inner circumferential surface 11a, and the bolts 41 start to move in the acting direction in a state where they are pulled by the driven plate 10 as the driven plate 10 moves. For all six bolts 41 provided in the laminate L, the bolts 41 move in association with the movement of the driven plate 10 in the acting direction. Since the bolts 41 are inserted into a pair of slits 31a extending mutually along the acting direction (see FIG. 4), the direction in which the driven plate 10 moves can be determined to be the extending direction of the slits 31a.

[0046] FIG. 10 is a schematic graph illustrating the relationship between the load (tensile force) and displacement during initial slippage. In FIG. 10, the solid line portion corresponds to the initial slippage. During initial slippage, the tensile force on the driven plate 10 exceeds the critical value P0, and as a result, the driven plate 10 starts to move. Once the driven plate 10 starts to move, the load is significantly reduced and the low load state is maintained. Therefore, as shown in FIG. 10, the driven plate 10 continues to move in a state in which the load acting on the friction joint structure 1 is reduced to a value P1 that is smaller than the critical value P0.

[0047] In addition, when the buffer material 50 is arranged inside the first through hole 11 and the second through hole 21 (see FIG. 6), the load caused by the slippage of the driven plate 10 can be reduced while decreasing the movement start speed of the driven plate 10 compared to the case where the buffer material 50 is not arranged. Even if a sufficient separation distance cannot be secured between the shaft portion 41a and the first inner peripheral surface 11a, the second gap G2 larger than the first gap G1 is secured between the shaft portion 41a and the second inner peripheral surface 21a. Therefore, the load caused by the slippage of the driven plate 10 at the time of initial slippage can be reliably reduced.

[0048] Fig. 11(a) is a diagram showing the state immediately after the driven plate 20 starts to slide in the acting direction (driven plate moving state), and Fig. 11(b) is its DD cross-sectional view. Each arrow in Fig. 11(b) is the same as the arrow in Fig. 9(b), so detailed explanations are omitted.

[0049] At the end of the initial slip, the shaft portion 41a is in contact with both the first inner circumferential surface 11a and the second inner circumferential surface 21a in the acting direction. When the tensile force continues to act on the driving plate 10 from this state, a force (support pressure) against the acting direction is applied to the shaft portion 41a from the first inner circumferential surface 11a and the second inner circumferential surface 21a, and a support pressure in the opposite direction to the acting direction is applied from the driven plate 20. That is, the shaft portion 41a is sandwiched between the driving plate 10 and the driven plate 20 from both sides in the acting direction, and is in a support-joined state.

[0050] In the pressure-bonded state, the tensile force in the acting direction of the drive plate 10 is acted upon by a resultant force of the axial force from the connecting member 40 in the vertical direction, the support pressure generated in the shaft portion 41a, and the kinetic friction force generated between the drive plate 10 and the driven plate 20 and the intermediate member 30. Here, the kinetic friction force is generated between the driven plate 20 and the intermediate member 30 because the driven plate 20 begins to move away from the intermediate member 30 as a result of the continued increase in the tensile force.

[0051] Fig. 12 is a schematic graph illustrating the relationship between the load (tensile force) and displacement at the beginning of the movement of the driven plate 20. In Fig. 12, the solid line portion corresponds to the beginning of the movement of the driven plate 20. Not only a kinetic friction force is generated between the first contact surface 13 and the first sliding contact surface 32, but also a static friction force is generated between the second contact surface 22 and the second sliding contact surface 33, and the number of friction surfaces is increased compared to the previous initial state and the initial slip. For this reason, even if the load P1 acting at the initial slip is gradually increased, displacement is less likely to occur.

[0052] Fig. 13(a) is a diagram showing a state (final sliding state) in which the driven plate 20 is also moving in the same state as the driven plate 10, and Fig. 13(b) is an E-E cross-sectional view of Fig. 13(b). The arrows in Fig. 13(b) are the same as those in Fig. 9(b), so detailed explanations will be omitted.

[0053] At the time of the final slip, the tensile force in the acting direction of the driven plate 10 is greater than the resultant force of the axial force from the connecting member 40 in the vertical direction, the support force generated on the shaft portion 41a, and the kinetic friction force generated between the driven plate 10 and the intermediate member 30 and the driven plate 20. In particular, the tensile force greatly exceeds the resultant force of the support force and the kinetic friction force, as compared with the initial movement of the driven plate 20 described above. When the tensile force in the acting direction of the driven plate 10 becomes greater, the driven plate 20 also starts to move with the movement of the driven plate 10. As a result, a kinetic friction force is generated not only between the first contact surface 13 and the first sliding contact surface 32 but also between the second contact surface 22 and the second sliding contact surface 33, and the movement of the driven plate 10 and the driven plate 20 continues with the number of friction surfaces increased.

[0054] FIG. 14 is a schematic graph illustrating the relationship between the load (tensile force) and displacement at the time of final slippage. In FIG. 14, the solid line portion corresponds to the time of final slippage. As the driven plate 20 starts to move with the movement of the driving plate 10, the number of friction surfaces increases compared to the initial movement of the driven plate 20. Since the kinetic friction force is smaller than the static friction force, the driving plate 10 and the driven plate 20 continue to move with the tensile force (load P2) being less than the critical value P0. On the other hand, since the load P2 is a value larger than the load P1 acting at the time of the initial slippage, the load is maintained at a high level, and the amount of energy absorption can be increased.

[0055] In this way, in the friction joint structure 1 according to the present embodiment, the friction resistance force before slippage is suppressed by passing through the initial state, the initial sliding state, the driven plate moving state, and the final sliding state, and the friction resistance force after slippage is increased, thereby improving the vibration energy absorption performance. That is, while the load (tensile force) is increased only to the driving plate 10 up to the critical value P0, the load is once reduced, and the driven plate 20 starts to move in the acting direction with the driving plate 10 moving in the acting direction, and the load is increased again. As a result, the friction resistance force is shifted from a state in which the friction resistance force is generated only between the driving plate 10 at first to a state in which the friction resistance force is significantly reduced, and then to a state in which the friction resistance force is generated between the driving plate 10 and the driven plate 20 again, so that the friction resistance force can be generated in two stages over a long period of time, and as a result, the vibration energy absorption performance can be improved.

[0056] Although an embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes that do not deviate from the gist of the present invention are included in the present invention.

[0057] For example, in the embodiment shown in Fig. 6, the cushioning material 50 is arranged so as to cover the entire outer periphery of the shaft portion 41a of the bolt 41, but the shaft portion 41a may have a part of its periphery where the cushioning material 50 is not arranged. That is, the shaft portion 41a may have a part that is not covered by the cushioning material 50 in either the axial direction or the circumferential direction of the shaft portion 41a. [Explanation of symbols]

[0058] 1 Friction bonding structure 10 Main moving plate 11 First through hole 20 Driven plate 21 Second through hole 30 Intermediate parts 31 Information Department 31a Slit 40 Connecting member 41 Volts 42 Nut 43 Washer 50 Cushioning material L laminate

Claims

1. A friction joining structure in which relative movement between stacked members is suppressed by frictional resistance force generated by surface contact between stacked members, a flat driving plate having a first through hole formed in a plate thickness direction; a flat driven plate having a second through hole formed in a plate thickness direction; a flat intermediate member disposed between the driving plate and the driven plate; a connecting member including a bolt inserted into the first through hole and the second through hole, a nut screwed onto the bolt, and a pair of washers through which the bolt is inserted, the connecting member introducing a fastening force via the pair of washers to a stacked body formed of the driving plate, the driven plate, and the intermediate member, a guide portion on which the bolt can move is formed on the intermediate member, and when a force in a surface direction acts to separate the driving plate from the intermediate member, the driving plate is guided in an acting direction in a state of being in surface contact with the intermediate member as the bolt moves along the guide portion, The first through hole and the second through hole each have a diameter larger than a shank of the bolt, A friction joint structure, characterized in that the driven plate starts to move in the acting direction as the driven plate moves in the acting direction.

2. The friction joining structure according to claim 1, A cushioning material is further provided on the inside of the first through hole and the second through hole, A friction joint structure, characterized in that the outer periphery of the shaft portion of the bolt is covered with the cushioning material.

3. The friction joining structure according to claim 1 or 2, A friction joining structure, wherein the second through hole has a diameter larger than that of the first through hole.

4. The friction joining structure according to claim 1 or 2, A friction joining structure, characterized in that the guide portion is configured to have a pair of slits extending parallel to each other along the acting direction.

5. The friction joining structure according to claim 4, The first through holes are formed in a plurality of groups along the action direction to constitute a first through hole group, The second through holes are formed in a plurality of groups along the action direction to constitute a second through hole group, A friction joining structure characterized in that the first group of through holes and the second group of through holes are arranged in two rows in a direction perpendicular to the action direction, while being aligned with either of the pair of slits in a planar view.

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