JP2915901B1 - High strength bolt joint structure - Google Patents

Abstract

Abstract: PROBLEM TO BE SOLVED: To provide a high-strength bolted joint that can reduce the protrusion of a bolt tip into a rectangular steel pipe when a plate is to be joined with a high-strength bolt to a side wall of a square steel pipe material without a screw coming off. Provided is a high-strength bolted joint structure that can obtain a state and can be joined even when it can be accessed only from one side. A high-strength bolt (3) is provided on a side wall (1a) of a square steel pipe (1).
A screw nut 5 having a diameter larger than that of the screw hole 5 is formed, and a plug nut 4 having an outer periphery as a screw portion 7 is screwed into the screw hole 5, and the high-strength bolt 3 is plugged through a bolt through hole 10 of the plate 2. The rectangular steel pipe 1 and the plate 2 are screwed to the nut 4 and fastened, and are joined by high-strength bolts.
The plug nut 4 can be screwed into the screw hole 5 of the rectangular steel pipe 1 from outside the rectangular steel pipe 1 and attached.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a high-strength bolt joint structure.

[0002]

2. Description of the Related Art In a case where another member, for example, a plate 57 is joined to a side wall of a metal tubular material, for example, a rectangular steel pipe member 51 by high-strength bolts, as shown in FIG. A high-strength bolt 53 is inserted into a screw hole 52 provided on the side wall of the material 51.
In the method of screwing and tightening, there is a danger that the screw may come off. Therefore, as shown in FIGS. A back plate 54 having a 55 is arranged, and a high-strength bolt 53 is screwed to these and tightened.

[0003]

However, in the structure in which the high-strength bolt 53 is screwed into the nut 56 or the back plate 54 disposed inside the rectangular steel pipe material 51 as described above, the rectangular steel pipe material 51 is used. There is a drawback that the protrusion of the bolt 53 inwardly increases.

[0004] This is, for example, as shown in FIG.
When the plates 57, 57 are to be joined to the side walls 51a, 51a of the rectangular steel pipe 51 by high-strength bolts, the bolts 53, 53 interfere with each other inside the rectangular steel pipe 51, and the joining is performed. This can cause difficulties. In particular, in order to reduce the out-of-plane deformation of the side walls 51a, the adjacent side walls 51a, 51a
When a high-strength bolt joint is to be performed at a position close to the connection corner of the bolt, it may be difficult to perform the bolt joint at such a position.

[0005] In the case of the rectangular steel pipe 51 as described above, it is often difficult or impossible to arrange the nut 56 and the back plate 54 inside.

The present invention has been made in view of the above-mentioned conventional problems, and for example, in a case where another member is to be joined with a high-strength bolt to the side wall of the rectangular steel tube material as described above,
Bolts that can minimize the protrusion on the bolt tip side, and that can obtain a firm joining state without screws coming out, and can also join even when access is possible from only one side It is an object to provide a joint structure.

[0007]

The above object is achieved by providing a first member with a screw hole having a diameter larger than that of a high-strength bolt.
A nut member having an outer peripheral threaded portion is attached to the member by screwing the outer peripheral threaded portion to the screw hole, and a high-strength bolt is inserted into the nut material through the bolt through hole of the second member. The first member and the second member are joined to each other by the screw coupling force of the nut member and the first member and the high-strength bolt and the nut member, and the first member and the second member are joined by the high-strength bolt. And a nut member which can be screwed into a screw hole of the first member through a surface of a frictional joining surface between the first member and the second member, and can be attached. It is solved by a bolt joint structure.

That is, according to this high-strength bolt joining structure,
Since the nut member is set in the first member, the protrusion of the high-strength bolt on the tip side can be suppressed to a small value.

Moreover, since the high-strength bolt is screwed with the nut material, the bolt does not come off from the nut material due to the tightening of the high-strength bolt. The screw hole is larger in diameter than the high-strength bolt, so that the screw length in the spiral direction of the screw hole is ensured longer, and therefore, the proof strength of the screw joint between the nut material and the first member is increased. In addition, also with respect to the nut material, it is possible to obtain a firmly screwed state in which the screw is not easily removed from the first member. Therefore, the first member and the second
Can be made into a firm high-strength bolted state without screw removal, that is, a firmly friction-joined state.

[0010] In addition, the nut member can be screwed into the screw hole of the first member from the side of the frictional joint surface between the first member and the second member, so that it can be mounted on one side. Even in a case where it can be accessed only from the outside, a firm high-strength bolt connection can be performed.

[0011] In the above joint structure, the diameter of the screw hole of the first member is set such that the pull-out tensile load of the nut material from the screw hole is larger than the tensile breaking load of the high-strength bolt. Thereby, the nut member can be securely prevented from being unthreaded from the screw hole of the first member, and the first member and the second member can be securely joined by a high-strength bolt in a frictionally joined state.

Further, the nut member has an end face facing the second member flush with a frictional joining surface between the first member and the second member, or is separated from the second member so that the first member is separated from the first member. By being screwed into the screw hole while being retracted into the screw hole, the tightening force of the high-strength bolt is used as the inter-material compression force between the first member and the second member. Thus, the first member and the second member can be brought into a firm friction-joined state. In particular, as described above, the end face of the nut
By separating the first member from the second member and retreating into the screw hole of the first member, the frictional joining between the first member and the second member can be ensured.

[0013]

Next, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1 and 2 show a structure in which a plate is joined to an outer surface of a square steel pipe by high-strength bolts.
1 is a square steel pipe as a first member, 2 is a plate as a second member, 3 is a high-strength bolt, and 4 is a plug nut as a nut material.

The rectangular steel pipe 1 is made of a normal mild steel class structural steel, and has a threaded hole 5 having a diameter larger than that of the high-strength bolt 3 used for joining in a side wall 1a.

The plug nut 4 has a hardness determined as a set with the high-strength bolt 3, and has a screw hole 6 in its shaft core for screwing the high-strength bolt 3. The plug nut 4 has a circular cross-sectional outer peripheral shape, and the outer peripheral size is the screw hole 5 of the square steel pipe material 1.
A male screw 7 that can be screwed into the screw hole 5 of the rectangular steel pipe 1 is formed on the outer peripheral portion. The frictional joint surface between the plate 1 and the plate 2 is configured to be screwed in from the outside of the rectangular steel tube 1, that is, to be attached.

The high-strength bolt connection of the plate 2 to the rectangular steel pipe 1 is performed as follows. That is, first, the plug nut 4 is attached to the square steel pipe 1 by screwing the plug nut 4 into the screw hole 5 from the outside of the square steel pipe 1.

For the operation of screwing the plug nut 4 into the screw hole 5 of the rectangular steel pipe material 1, tool engaging portions 8, 8 are provided on the base end surface of the plug nut 4. In this embodiment,
A plurality of small holes 8 for rotation operation are provided on the proximal end face of the plug nut 4.
Is provided in an eccentric state, and this is used as a tool engagement portion. A projection of a rotary tool (not shown) is inserted into the small holes 8 and 8 and the rotary tool is rotated, whereby the plug nut 4 is screwed into the screw hole of the square steel pipe material 1. 5 is screwed. Note that the tool engaging portion may be of any mode in which the tool can be engaged with the plug nut 4 and the plug nut 4 can be rotated by operating the tool. The groove may have various shapes such as a minus-shaped groove or a plus-shaped groove crossing the base end surface of the plug nut 4.

The plug nut 4 may be set in the screw hole 5 so that the base end surface thereof is flush with the outer surface of the rectangular steel pipe 1, but the frictional connection between the rectangular steel pipe 1 and the plate 2 is ensured. As shown in FIG. 1, the plug nut 4 is set so that its base end surface is slightly inserted into the screw hole 5 from the position of the outer surface of the rectangular steel pipe 1. Is good.

In order to prevent the plug nut 4 set in the screw hole 5 from rotating unintentionally, such as rotating together when the high-strength bolt 3 is tightened, the plug nut 4 and the square steel pipe are prevented from rotating. It is preferable to apply an adhesive to the screwed portion with the material 1. Alternatively, as shown in FIG. 4, a chamfered portion 11 is formed in the opening of the screw hole 5 on the outer surface side of the rectangular steel pipe material 1, and the base end of the plug nut 4 projects radially outward. The plug nut 4 may be prevented from further screwing into the screw hole 5 by providing the flange portion 12 to be provided and abutting the flange portion 12 against the chamfered portion 11. .

Thereafter, the high-strength bolt 3 is passed through the washer 9, through the bolt through hole 10 of the plate 2, and screwed into the plug nut 4 of the square steel pipe 1, and tightened. Joined. As described above, the plate 2 and the square steel pipe 1 are joined by high-strength bolts.

In the above-described high-strength bolt joint structure, the projection of the plug nut 4 behind the side wall 1a can be suppressed to a small extent, because the plug nut 4 is located within the wall of the side wall 1a of the rectangular steel pipe material 1. Therefore, the protrusion of the tip of the high-strength bolt 3 screwed into the plug nut 4 and tightened can be reduced. Therefore, for example, as shown in FIG. 3, even when the plates 2 and 2 are bolted to the adjacent side walls 1 a and 1 a of the rectangular steel pipe 1, the bolts 1 a and 1 a do not interfere with each other. It becomes possible to join, and it is also possible to perform high-strength bolt joining at a position near the connecting corner of the adjacent side walls 1a, 1a, thereby realizing a joining structure with small out-of-plane deformation of the side walls 1a, 1a. can do.

Further, since the high-strength bolt 3 is screwed into the plug nut 4 screwed into the screw hole 5 instead of the screw hole 5 of the rectangular steel pipe material 1, the high-strength bolt 3 is tightened. The strength of the screw portion between the plug 3 and the plug nut 4 can be secured large, and the high-strength bolt 3 does not come off from the plug nut 4 due to the tensile force acting on the high-strength bolt 3. In addition, the square steel pipe 1 has a screw hole 5 larger than the bolt diameter of the high-strength bolt 3.
Is provided, the screw length of the screw hole 5 in the helical direction can be lengthened accordingly, and the screwing between the plug nut 4 and the screw hole 5 becomes firmly strong. Also, the screw removal of the plug nut 4 from the rectangular steel pipe 1 is effectively prevented. Accordingly, the square steel pipe 1 and the plate 2 can be joined by high-strength bolts, that is, frictionally joined in a strong and firmly joined state without screw removal.

FIG. 6 shows that the tensile strength is 41 kgf.
6 shows the relationship between the plate thickness and the tensile strength of the screw portion of the screw hole when a screw hole is formed in a plate of / mm ² for plug rats of various outer diameters. For example, if the breaking load is 3
5.3tf high strength bolt F10T-M2 with 24mm diameter
In the case of using No. 4, if the thickness of the plate is 24 mm, by using a plug nut having an outer diameter of 33 mm, the high-strength bolt F10T-M24 has the plug nut pulled out of the screw hole of the plate. It is fractured before and a high-strength bolted state without screws coming out can be obtained.

In addition, since the plug nut 4 is configured so that the external thread portion 7 provided on the outer peripheral portion thereof can be screwed into the screw hole 5 of the rectangular steel tube material 1 from the outside, and attached. Rectangular steel pipe material 1 with difficult access to the inside
Even in this case, the plug nut 4 can be easily attached from the outside of the rectangular steel pipe 1.

The modified example shown in FIG. 5A is a case where a high-strength bolt 3 with a pin tail is used. When the tightening torque reaches a predetermined torque in the tightening process of the bolt 3, the pin tail 3a is cut off. A predetermined axial force is stably introduced into the bolt 3.

In the embodiment shown in FIG. 5B, a thick member 15 as a first member is attached to a plate 2 as a second member.
Are joined by high-strength bolts. The thick material 15 is provided with a shallow screw hole 5 with a bottom for screwing the plug nut 4, into which the plug nut 4 is screwed. Then, the high-strength bolt 3 is passed through the through hole 10 of the plate 2, screwed into the plug nut 4 and tightened, and the plate 2 is joined to the thick material 15 by high-strength bolt. In the present embodiment, the screw holes 5 formed in the thick material 15
High-strength bolt 3 inward of the thick material 15
The plate 2 can be firmly joined to the thick material 15 with high-strength bolts while reducing the protrusion of the tip of the thick material 15, that is, while reducing the amount of processing of the screw hole 5 in the thick material 15.

Although the embodiment of the present invention has been described above, the present invention is not limited to this, and various modifications can be made without departing from the spirit of the invention. For example, in the above-described embodiment, the case where the square steel pipe 1 or the thick material 15 is used as the first member and the plate 2 is used as the second member has been described. May be applied. Further, in the above-described embodiment, a case where a high-strength bolt with a head is used as the high-strength bolt is shown. Alternatively, a joining structure in which a high-strength full-screw bolt is used and a nut is screwed into the bolt to fasten it may be used.

[0029]

As described above, since the high-strength bolt joining structure of the present invention has the above-described structure, the protrusion at the tip end of the bolt can be suppressed small.
A high-strength bolted joint without a screw coming off can be obtained. In addition, high-strength bolted joint can be performed even when it can be accessed only from one side.

[Brief description of the drawings]

FIG. 1 is a sectional plan view showing a high-strength bolt joining structure according to an embodiment.

FIG. 2 is an exploded perspective view, partly in section, of the same structure.

FIG. 3 is a cross-sectional plan view showing an example of a usage mode of the same structure.

FIG. 4 is a sectional plan view showing a modification of the high-strength bolt joint structure.

FIG. 5A is a cross-sectional plan view showing a modification of the high-strength bolt joint structure, and FIG. 5B is a cross-sectional side view showing still another modification.

FIG. 6 is a graph showing the relationship between plate thickness and screw hole strength.

FIGS. 7A to 7C are cross-sectional plan views each showing a conventional bolted structure. FIG.

FIG. 8 is a cross-sectional plan view showing a usage mode of the structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Square steel pipe material (1st member) 2 ... Plate (2nd member) 3 ... High-strength bolt 4 ... Plug nut (nut material) 5 ... Screw hole 6 ... Inner peripheral thread part 7 ... Outer peripheral male thread part 10 … Through hole

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) E04B 1/24 E04B 1/38 F16B 37/04

Claims (3)

(57) [Claims] A first member provided with a screw hole having a diameter larger than that of the high-strength bolt; a nut member having an outer peripheral thread portion in the first member; A high-strength bolt is screwed into the inner peripheral thread portion of the nut member and tightened through a bolt through hole of the second member, and the nut member and the first member, and the high-strength bolt The first member and the second member are joined by high-strength bolts by the respective screw coupling forces of the nut member and the nut member. A high-strength bolt joint structure, wherein a frictional joint surface with the second member can be screwed into and attached to the second member. 2. The high-diameter screw according to claim 1, wherein a diameter of the screw hole is set such that a pull-out tensile load of the nut material from the screw hole is larger than a tensile breaking load of the high-strength bolt. Force bolt joint structure. 3. An end face of the nut member facing the second member is flush with a frictional joining surface between the first member and the second member, or is separated from the second member and the first member is separated from the first member. 2. The screw member is screwed into the screw hole while being retracted into the screw hole of the member.
The high-strength bolt joint structure according to 1.