JP6941468B2 - Axial force member end joint structure and bolts - Google Patents

Description

The present invention relates to end joint structures and bolts of axial force members such as dampers and buckling restraint braces.

Axial force members such as dampers and buckling restraint braces are often bolted to the structure at both ends via clevis, ball joints, etc. (see, for example, Patent Document 1). Further, as a joining method for both ends of this type of axial force member, tensile joining using bolts and nuts is often used.

Here, as shown in FIG. 12, in the damper 2 in which both ends 2a and 2b are bolted to the structure via the ball joint 1, when a force (Fy, Fz) orthogonal to the damper axial direction acts, the ball The joint 1 rotates and the damper 2 follows the deformation. As a result, when an external force acts, the damper axial force Fx is transmitted, and the forces Fy and Fz orthogonal to the damper axial direction become almost zero. Further, as the ball joint 1 rotates, torque T (transmission torque) around the damper shaft is hardly generated.

Japanese Unexamined Patent Publication No. 2005-121141

However, in the method of bolting both ends of an axial force member such as a damper as described above, the reaction force is leveled off by a relief load, a yield load, or the like within the normal application range. On the other hand, when an unexpected input exceeds the permissible displacement / stroke, an excessive reaction force is generated after reaching the stroke limit, which may cause great damage to the main body structure.

Therefore, it has been required to provide a fail-safe mechanism that does not generate an excessive reaction force at the damper fixing end (joint end portion) even when an unexpectedly large external force is input.

In view of the above circumstances, the present invention provides an end joint structure and a bolt of an axial force member capable of preventing an excessive reaction force from being generated at a joint end even when an external force of an unexpected magnitude is input. The purpose is to do.

To achieve the above object, the present invention provides the following means.

The end joint structure of the axial force member of the present invention is a joint structure of the end portion of the axial force member in which an external force acts and an axial force is generated, and a bolt and a nut are joined to the end portion of the axial force member. The bolt is formed by friction-joining the shaft and the head, and the shaft of the bolt is not screwed with a male screw on the outer peripheral surface on the rear end side in the axial direction. A die that is formed with a frictional joint and is integrally attached by fitting the frictional joint so that the head of the bolt is in surface contact with the outer peripheral surface and the inner peripheral surface of the frictional joint of the shaft. And the covering member that is integrally provided so as to include the die and forms the outer peripheral surface of the head of the bolt, and the outer peripheral surface of the die and the outer peripheral surface of the die are in surface contact with each other. The frictional resistance between the inner peripheral surface of the covering member is the frictional resistance between the outer peripheral surface of the frictional joint where the male screw is not screwed on the outer peripheral surface of the shaft portion of the bolt and the inner peripheral surface of the die. It is characterized by being configured as larger.

In the end joining structure of the axial force member of the present invention, it is desirable that an elastic body is interposed between the head of the bolt and the joining target and / or between the nut and the joining target.

End junction structure of the axial force member of the present invention is a joint structure of the end portion of the axial force member axial force is generated with external force, the bolt ends of the axial force member to be joined and Along with bolt joining using a nut, the bolt is formed by frictionally joining the shaft and the head, and the shaft of the bolt is screwed with a male screw on the outer peripheral surface on the rear end side in the axial direction. formed with a non friction joint, the head of the bolt, characterized in that it is constituted by a pair of pressing plate holding clamp sandwiches the friction joint of the shaft portion of the bolt.

The bolt of the present invention is formed by frictionally joining a shaft portion and a head portion, and the shaft portion is provided with a friction joint portion on the rear end side in the axial direction in which a male screw is not screwed on the outer peripheral surface. The head is formed so as to include the die and the die that is integrally attached by fitting the friction joint so that the outer peripheral surface and the inner peripheral surface of the friction joint of the shaft are in surface contact with each other. integrally provided, it is constituted by a covering member forming the outer peripheral surface of the front Kiatama portion, between the inner peripheral surface of the cover member outer peripheral surface and the outer circumferential surface of the die of the die surface contact The frictional resistance of the shaft portion is larger than the frictional resistance between the outer peripheral surface of the frictional joint where the male screw is not screwed on the outer peripheral surface of the shaft portion and the inner peripheral surface of the die. do.

Bolt of the present invention is formed by friction joining the shaft portion and a head, said shank, the rear end side in the axial direction, provided with a friction joint male screw is not threaded to the outer peripheral surface It formed Te, the head, characterized in that it is constituted by a pair of pressing plates for clamping holding sandwiches the friction joint of the shaft portion.

In the end joint structure and bolt of the axial force member of the present invention, by frictionally joining the shaft portion and the head to form the bolt, an unexpectedly excessive input acts on the axial force member such as a damper. By breaking the friction between the shaft of the bolt and the head and causing relative displacement, it is possible to forcibly release the joint with the structure while leveling off the reaction force.

That is, even if an unexpectedly excessive input acts on the axial force member and reaches the stroke end by the bolt that frictionally joins the shaft and the head, the reaction force is leveled off and the joint with the structure is forced. It is possible to configure a fuse mechanism (fail-safe mechanism) to release the fuse.

Thereby, by adopting the end joint structure and the bolt of the axial force member of the present invention, it is possible to surely prevent the structure from being damaged by the reaction force from the axial force member such as the damper.

It is sectional drawing which shows the end joint structure of the axial force member which concerns on 1st Embodiment of this invention. It is an enlarged view of the S part of FIG. It is the X1-X1 line arrow view of FIG. It is the X2-X2 line arrow view of FIG. It is an exploded perspective view which shows the bolt which concerns on 1st Embodiment of this invention. It is a front view which shows the bolt which concerns on 1st Embodiment of this invention. It is an enlarged view of the end joint structure (S part of FIG. 1) of the axial force member which concerns on 2nd Embodiment of this invention. FIG. 7 is a view taken along the line X1-X1 of FIG. FIG. 7 is a view taken along the line X2-X2 of FIG. It is an exploded perspective view which shows the bolt which concerns on 2nd Embodiment of this invention. It is a front view which shows the bolt which concerns on 2nd Embodiment of this invention. It is a figure which shows the axial force member.

Hereinafter, the end joint structure and the bolt of the axial force member according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 6. Here, the present embodiment will be described assuming that the axial force member is a damper, but the axial force member according to the present invention is any member such as a buckling restraint brace in which an external force acts and an axial force is generated. It can be applied as a joint structure at the end of.

In the end joining structure A of the axial force member of the present embodiment, as shown in FIGS. 1 and 12, both end portions 2a and 2b of the damper 2 are bolted to the structure 5 to be joined via the ball joint 1. When a force (Fy, Fz) orthogonal to the damper axial direction acts, the ball joint 1 rotates and the damper 2 follows the deformation. As a result, when an external force acts, the damper axial force Fx is transmitted, the forces Fy and Fz orthogonal to the damper axial direction become almost 0, and the rotation of the ball joint 1 causes the torque T around the damper axis ( Transmission torque) is hardly generated.

Further, as shown in FIGS. 1 to 4, the end joint structure A of the axial force member of the present embodiment has a structure with the end portions 2a and 2b of the axial force member 2 to be bolted, for example, a ball joint or a clevis. A disc spring 6 and a washer 7 which are elastic bodies are interposed between the body 5 and the structure 5 and the nut 4. As a result, the tension introduced into the bolt 3 can be controlled by the deflection of the countersunk spring 6, and excessive tension introduction can be prevented.

As the bolt 3 for tension-joining the axial force member 2 to the structure 5, for example, a high-strength bolt and an anchor bolt are applied.

On the other hand, as shown in FIGS. 1 to 6, the bolt 3 of the end joint structure A of the axial force member of the present embodiment is configured such that the head portion 10 is coupled to the shaft portion 11 of the bolt 3 by frictional force. Has been done. That is, in the field, the end portion 2a (2b) of the axial force member 2 can be bolted to the joint target such as the structure 5 by rotating the nut 4 in the same manner as a normal bolt. The bolt joint portion in which the portion 10 and the shaft portion 11 are frictionally joined is configured to be a fuse mechanism (fail safe mechanism).

Specifically, the bolt 3 used in the end joining structure A of the axial force member of the present embodiment has a cylindrical rod-shaped friction joining portion 11b that does not form a male screw 11a of the shaft portion 11 of the cylindrical die 12. It is fitted into the inner hole, the friction joint portion 11b of the die 12 and the bolt 3 is frictionally joined, and further, in this state, the cap-shaped outer cylinder (covering member) 9 is integrally joined to the outside of the die 12 to form the bolt 3. The head 10 is formed.

The inner diameter of the die 12 is substantially the same as the outer diameter of the friction joint portion 11b of the bolt shaft portion 11 (slightly smaller dimension), and when an excessive axial force is applied to the bolt 3, the outer peripheral surface of the shaft portion 11 is formed. The die 12 is configured to slide with respect to the shaft portion 11 by breaking the friction between the die 12 and the inner peripheral surface of the die 12. By setting the frictional resistance force when the die 12 slides relative to the bolt shaft portion 11 as the limiting axial force, the bolt joint portion can be configured as a fail-safe mechanism.

The bolt 3 of the present embodiment is manufactured in a factory and is in the state shown in FIG. 6 when it is brought into the site, and can be handled in the same manner as a general bolt. Further, the fail-safe mechanism can be compactly realized by the bolt head 10.

It is preferable that the outer cylinder 9 is brought into close contact with the die 12 to prevent rainwater and dust from entering the sliding surface. Further, screws may be provided on the outer peripheral surface of the die 12 and the inner peripheral surface of the outer cylinder 9 to integrate the two. By providing the outer cylinder 9, only the outer cylinder 9 can be brought into contact with the joint plate (base plate) of the ball joint 1, and the external force acting on the die 12 can be limited to the sliding resistance force.

Here, the die 12 has a cylindrical (pipe) shape, but it may be formed in a C shape or may be divided into a plurality of pieces. Further, it is preferable that the outer peripheral surface of the die 12 is roughened or the like to increase the unevenness so that the friction coefficient is larger than that of the inner peripheral surface. Further, the outer peripheral surface of the die 12 and the inner peripheral surface of the outer cylinder 9 may be tapered (inclined) so as to be fitted into the outer cylinder 9 like a wedge. With such a configuration, the sliding friction resistance force can be easily adjusted.

For example, when the outer peripheral surface of the die 12 and the inner peripheral surface of the outer cylinder 9 are tapered, the bolt shaft portion 11 is inserted inside the outer cylinder 9 and the die 12 is press-fitted into the gap between the two to be tapered. A compressive force (surface pressure) can be applied between the die 12 and the bolt shaft portion 11, and the friction caused by the compressive force makes it possible to develop a sliding resistance force. Therefore, the larger the press-fitting amount (pushing amount into the outer cylinder 9) of the die 12, the more the compressive force and the sliding frictional resistance force can be increased, which is adjusted when the bolt head 10 is manufactured at the factory. However, it is possible to easily obtain a predetermined sliding resistance force.

The die 12 is in contact with the outer cylinder 9 on the outer peripheral surface and the bolt shaft portion 11 on the inner peripheral surface, but slip does not occur on the outer peripheral surface because the friction coefficient with the outer cylinder 9 is larger than the inner peripheral surface, and the inner circumference Only sliding with the bolt shaft portion 11 on the surface will occur. Further, in the unlikely event that a slip occurs between the outer peripheral surface and the outer cylinder 9, the surface pressure decreases and comes out if there is a taper, and the surface pressure between the inner peripheral surface of the die 12 and the bolt shaft portion 11 Will drop and the bolt shaft portion 11 will come out of the die 12. This is a fail-safe mechanism against the case where the sliding between the inner peripheral surface of the die 12 and the bolt shaft portion 11 is hindered for some reason. It will be positioned as.

Further, when the diameter of the bolt shaft portion 11 is insufficient to obtain the sliding resistance force, the diameter of the unthreaded friction joint portion 11b is made larger than the shaft diameter of the male screw portion 11a of the bolt shaft portion 11. Therefore, the area of the sliding portion can be increased.

In this case, the bolt holes of the joint plates of the structure 5 and the ball joint 1 are set to be equal to or larger than the "diameter of the unthreaded friction joint portion 11b of the bolt shaft portion 11" so that the bolt shaft portion 11 can be pulled out.

It can be said that the end joint structure A of the axial force member of the present embodiment having the above configuration basically comprises a friction damper composed of the shaft portion 11 of the bolt 3 and the head portion 10. As a result, even if the head portion 10 is detached from the shaft portion 11, it can be reused by refitting it. In addition, it is possible to reduce the variation in frictional force by inspecting all of them at the factory before shipping. Furthermore, although the frictional force generally varies widely due to individual differences, the variation when retested with the same test piece is small, so if the performance is grasped in the shipping test, the performance can be almost reproduced even in the field.

Further, if the shaft portion 11 of the bolt 3 is disengaged from the head portion 10, the axial force member 2 including the ball joint 1 may fall. Therefore, a fall prevention wire is attached to the axial force member 2 or the joint member such as the ball joint 1. It is preferable to add it.

Therefore, in the end joint structure A and the bolt 3 of the axial force member of the present embodiment, the axial force member 2 such as a damper is assumed by frictionally joining the shaft portion 11 and the head portion 10 to form the bolt 3. When an excessive input from the outside acts, the friction between the shaft portion 11 of the bolt 3 and the head portion 10 is cut off and the head portion 10 is displaced relative to each other, so that the joint with the structure 5 can be forcibly released while the reaction force is leveled off. can.

That is, even when an unexpectedly excessive input acts on the axial force member 2 by the bolt 3 in which the shaft portion 11 and the head portion 10 are frictionally joined to reach the stroke end, the reaction force is leveled off and the structure 5 and the structure 5 are formed. It is possible to configure a fuse mechanism (fail-safe mechanism) that forcibly releases the connection between the two.

Thereby, by adopting the end joint structure A and the bolt 3 of the axial force member of the present embodiment, it is possible to surely prevent the structure 5 from being damaged by the reaction force from the axial force member 2 such as the damper.

Furthermore, compared to the conventional tensile joint using conventional bolts, the bolt 3 has almost the same member structure except for the larger head, so no special equipment, skill or construction method is required for application, and the existing construction method Can be followed.

Next, with reference to FIGS. 7 to 11 (and FIG. 1), the end joint structure and the bolt of the axial force member according to the second embodiment of the present invention will be described. Similar to the first embodiment, the present embodiment is configured so that the head of the bolt is coupled to the shaft portion of the bolt by frictional force, and the bolt joint portion is configured as a fail-safe mechanism to join the end of the axial force member. It is about the structure and bolts. Therefore, the same reference numerals are given to the same configurations as in the first embodiment, and detailed description thereof will be omitted.

As shown in FIGS. 7 to 11, in the end joint structure A of the axial force member of the present embodiment, the rear end portion of the cylindrical rod-shaped friction joint portion 11b in which the male screw 11a of the shaft portion 11 of the bolt 3 is not formed. Is sandwiched between a pair of pressure plates 13, and the head portion 10 of the bolt 3 is configured. Further, each of the pair of pressure plates 13 is provided with a recess 13a having an arcuate cross section on the inner peripheral surface thereof, and the friction joint portion 11b of the bolt 3 is engaged with the recesses 13a of the pair of pressure plates 13 facing each other. The joint portion 11b is sandwiched between a pair of pressure plates 13 and frictionally joined.

Further, bolt insertion holes 13b are formed through the pair of pressure plates 13 on both sides of the friction joint portion 11b of the bolts 3, and the pressure bolts 14 are communicated with the bolt insertion holes 13b of the pair of pressure plates 13. The pressure plate 13 is pressed against the friction joint portion 11b of the bolt 3 by fastening the pressurizing nut 15 at the same time, and the friction joint portion 11b of the bolt 3 is sandwiched between the pair of pressure plates 13. Further, a pressurizing disc spring 16 and a washer 17 are interposed between the pressurizing bolt 14 and the pressurizing plate 13, or between the pressurizing nut 15 and the pressurizing plate 13, and the elastic force of the disc spring 16 sandwiches the bolt 3. The force can be adjusted.

Here, the friction material 18 (brake material or slip material having a friction coefficient μ> 0.25) is attached to the inner peripheral surface of the pressure plate 13, and the bolt shaft portion 11 is formed by the recesses 13a of the pair of pressure plates 13. The friction material 18 may be configured to slide with respect to the shaft portion 11 when it is inserted into the gap portion and pressure is applied from both sides of the pressure plate 13 and an excessive axial force acts on the bolt 3. In this case, the friction plate 18 may be integrated with the pressure plate 13.

The bolt 3 of the present embodiment can be handled in the same manner as a general bolt if it is manufactured in the factory in advance. Although the bolt head 10 is larger than that of the first embodiment, it is easy to handle a frictional force larger than that of the first embodiment.

Further, as in the first embodiment, when the diameter of the bolt shaft portion 11 is insufficient in order to obtain a sliding resistance force, for example, a frictional joint portion in which the bolt shaft portion 11 is not threaded from the shaft diameter of the male screw portion 11a. The diameter of 11b may be increased to increase the area of the sliding portion. Even in this case, the bolt holes of the joint plates of the structure 5 and the ball joint 1 are set to be equal to or larger than the “diameter of the unthreaded friction joint portion 11b of the bolt shaft portion 11”.

Further, in the end joint structure A of the axial force member of the present embodiment, it can be said that the friction damper is basically formed by the shaft portion 11 of the bolt 3 and the head portion 10 as in the first embodiment. As a result, even if the head portion 10 is detached from the shaft portion 11, it can be reused by refitting it. In addition, it is possible to reduce the variation in frictional force by inspecting all of them at the factory before shipping. Furthermore, although the frictional force generally varies widely due to individual differences, the variation when retested with the same test piece is small, so if the performance is grasped in the shipping test, the performance can be almost reproduced even in the field.

Further, if the shaft portion 11 of the bolt 3 is disengaged from the head portion 10, the axial force member 2 including the ball joint 1 may fall. Therefore, a fall prevention wire is attached to the axial force member 2 or the joint member such as the ball joint 1. It is preferable to add it.

Therefore, even in the end joint structure A and the bolt 3 of the axial force member of the present embodiment, the axial force member 2 such as a damper is assumed by frictionally joining the shaft portion 11 and the head portion 10 to form the bolt 3. When an excessive external input acts and the friction between the shaft portion 11 of the bolt 3 and the head portion 10 is cut off, the joint with the structure 5 can be forcibly released while the reaction force is leveled off.

Therefore, even if an unexpectedly excessive input acts on the axial force member 2 due to the bolt 3 in which the shaft portion 11 and the head portion 10 are frictionally joined to reach the stroke end, the reaction force is leveled off and the structure 5 and the structure 5 are formed. It is possible to configure a fuse mechanism (fail-safe mechanism) that forcibly releases the connection between the two.

Thereby, according to the end joint structure A and the bolt 3 of the axial force member of the present embodiment, it is possible to surely prevent the structure 5 from being damaged by the reaction force from the axial force member 2 such as the damper.

Furthermore, compared to the conventional tensile joint using conventional bolts, the bolt 3 has almost the same member structure except for the larger head, so no special equipment, skill or construction method is required for application, and the existing construction method Can be followed.

Although the end joint structure of the axial force member and the first and second embodiments of the bolt according to the present invention have been described above, the present invention is not limited to the above embodiment and does not deviate from the gist thereof. Can be changed as appropriate.

1 Ball joint 2 Axial force member 2a End 2b End 3 Bolt 4 Nut 5 Structure (to be joined)
6 Countersunk spring (elastic body)
7 Washer 9 Outer cylinder (covering member)
10 Head 11 Shaft 11a Male thread 11b Friction joint 12 Die 13 Pressurized plate 13a Recess 13b Bolt insertion hole 14 Pressurizing bolt 15 Pressurizing nut 16 Pressurizing disc spring 17 Washer 18 Friction material A End of axial force member Joint structure

Claims (5)

It is a joint structure at the end of the axial force member where an external force acts and an axial force is generated.
The end of the axial force member is bolted to the object to be joined using bolts and nuts, and the bolt is formed by frictionally joining the shaft and head.
The shaft portion of the bolt is formed so as to have a friction joint portion on the outer peripheral surface on the rear end side in the axial direction without a male screw being threaded.
The head of the bolt includes a die that is integrally attached by fitting the friction joint portion so that the outer peripheral surface and the inner peripheral surface of the friction joint portion of the shaft portion are in surface contact with each other, and the die. It is integrally provided and is configured to include a covering member that forms the outer peripheral surface of the head of the bolt.
The frictional resistance between the outer peripheral surface of the die and the inner peripheral surface of the covering member in which the outer peripheral surface of the die is in surface contact is the frictional joint portion where the male screw is not screwed on the outer peripheral surface of the shaft portion of the bolt. An end joint structure of an axial force member, which is configured to be larger than the frictional resistance between the outer peripheral surface of the die and the inner peripheral surface of the die. It is a joint structure at the end of the axial force member where an external force acts and an axial force is generated.
The end of the axial force member is bolted to the object to be joined using bolts and nuts, and the bolt is formed by frictionally joining the shaft and head.
The shaft portion of the bolt is formed on the rear end side in the axial direction with a friction joint portion on the outer peripheral surface on which no male screw is threaded.
An end joint structure of an axial force member, wherein the head of the bolt is provided with a pair of pressure plates for sandwiching and holding a friction joint portion of the shaft portion of the bolt. In the end joining structure of the axial force member according to claim 1 or 2.
An end joining structure of an axial force member, characterized in that an elastic body is interposed between the head of the bolt and the joining target and / or between the nut and the joining target. It is formed by frictionally joining the shaft and head.
The shaft portion is formed on the rear end side in the axial direction with a friction joint portion having no male screw threaded on the outer peripheral surface.
The head is integrally attached to the die by fitting the friction joint so that the outer peripheral surface and the inner peripheral surface of the friction joint of the shaft are in surface contact with each other, and the die is integrally attached so as to include the die. provided, it is constituted by a covering member forming the outer peripheral surface of the front Kiatama portion,
The frictional resistance between the outer peripheral surface of the die and the inner peripheral surface of the covering member in which the outer peripheral surface of the die is in surface contact is the outer circumference of the friction joint portion where the male screw is not screwed on the outer peripheral surface of the shaft portion. A bolt characterized in that it is configured to be larger than the frictional resistance between the surface and the inner peripheral surface of the die. It is formed by frictionally joining the shaft and head.
The shaft portion is formed on the rear end side in the axial direction with a friction joint portion having no male screw threaded on the outer peripheral surface.
A bolt characterized in that the head portion is provided with a pair of pressure plates for sandwiching and holding a friction joint portion of the shaft portion.

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