JP3252039B2 - Bolt loosening torque reduction structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for loosening a bolt provided at one end of a shaft portion having an external thread on its outer periphery for engaging an object to be fastened with a mounting member. The present invention relates to a bolt loosening torque reduction structure for reducing torque.

[0002]

2. Description of the Related Art When an object to be fastened is firmly fastened to a mounting body using a bolt, it may be necessary to remove the bolt for disassembly, repair, or the like. ， The bolts may not be easily loosened due to seizure.

In this case, conventionally, a large loosening torque is applied to the bolt to loosen it, or if the bolt is not loosened yet, the head of the bolt is scraped off with a cutter or the like or burned off with a burner.

[0004]

However, according to the above-mentioned conventional method, not only is the work of loosening the bolt extremely troublesome, but also the work may be damaged by the work, and the fastening state is released. It may be necessary to repair the work later, or in some cases it may not be possible to reuse the work, resulting in lower work efficiency, higher costs, and waste of resources. Was.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a bolt loosening torque reducing structure which solves the above-mentioned problem by enabling the bolt loosening operation to be easily and quickly performed with a small loosening torque. With the goal.

[0006]

In order to achieve the above-mentioned object, according to the first aspect of the present invention, an engaging portion for clamping an object to be fastened to a mounting member has a male screw screwed to the mounting member. In the bolt loosening torque reduction structure for reducing the bolt loosening torque provided at one end of the shaft portion on the outer periphery,
The bolt has an insertion hole portion at least a part of which extends along the axial direction corresponding to the object to be fastened, a locking portion connected to one end of the insertion hole portion and facing outward in the axial direction of the bolt, and a bolt mounting member. One end is connected to the other end of the insertion hole at the other end of the bolt from the screwing start point to the screw hole, and the other end of the bolt is coaxially provided with a screw hole having the other end opened outward. The auxiliary bolt inserted into the bolt, the head of the auxiliary bolt fits into the bolt and
It engaged previously threaded into the threaded hole One until it engages with the locking portion
In a state in which, I to the mounting body bolt through the fastened object
The bolts and auxiliary bolts are tightened.
The axial tension force acts on both the bolt and the bolt .

[0007] The invention of claim 2 is the invention of claim 1.
In addition to the above features, the auxiliary bolt is
It is characterized by being formed of a highly rigid material.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

[0009] First, in FIG. 1 showing a first embodiment of the present invention, the bolt B ₁ represents the engaging portion 3 ₁ a shaft portion which is formed a rotation operation tool such as a spanner in the cross section substantially regular hexagon as engageable is integrally connected to the 2 ₁ end, those formed by the external thread 1 is provided at least on the other end side outer circumference of the shaft portion 2 _1. Are those fastened object 4 by the bolt B ₁ is being fastened to the mounting member 5, screw holes 6 are provided in the mounting member 5, the fastened object 4, the shaft portion 2 ₁ of the bolt B ₁ An insertion hole 7 to be inserted is provided. Thus, the shaft portion 2 ₁ inserted through the insertion hole 7
By screwing the male screw 1 into the screw hole 6 and tightening it,
The fastened object 4 is sandwiched between the engaging portion 3 ₁ and the mounting body 5 of the bolt B _1, the fastened object 4 is to be fastened to the mounting member 5 thereby.

[0010] the bolt B ₁ is tightening was open at both ends hole 8
Are provided coaxially. The fastening holes 8, cross-section and a circular insertion hole 9, the bolt B insertion hole 9 in the _first engaging portion 3 ₁ side
And a screw hole 11 coaxially connected to the other end of the insertion hole 9. The locking portion 10 is formed in the axial direction. It is formed as a recess having a circular cross section facing outward. The range A in which the insertion hole 9 is provided is set so that at least a part of the insertion hole 9 along the axial direction corresponds to the workpiece 4 and the bolt B ₁
At the screwing start point P ₁ of the male screw 1 to the mounting body 5 at the position P _2, that is, at the position P ₂ which is shifted to the other end of the bolt B ₁ from the end of the screw hole 6 of the mounting body 5 on the workpiece 4 side. The part 11 is provided continuously to the other end of the insertion hole part 9.

An auxiliary bolt 12 is inserted into the tightening hole 8. The auxiliary bolt 12 has a head portion 13 engaged with the locking portion 10 integrally provided on the other end of a shaft portion 15 having an external thread 14 screwed into the screw hole portion 11 on one end side outer periphery. An engagement recess 16 having a regular hexagonal cross section for engaging a tool for rotating the auxiliary bolt 12 is provided on an end face of the head 13. In addition, auxiliary bolt 12
The head 13 of the auxiliary bolt 12
In state screwed in the screw hole portion 11 of the B _1, the bolt 12
It fits within ₁ and does not protrude beyond its outer surface.

Then, the bolt B ₁ is tightened and the object 4
Before fastening the mounting body 5, the auxiliary bolt 12 is engaged in advance with the threaded hole 11 to be engaged the head portion 13 to the matches and the engaging portion 10 to the bolt 12 _1, the In this state, the bolt B ₁ that penetrates the workpiece 4 is screwed into the mounting body 5 and tightened.

[0013] With such a structure, when the bolt B ₁ is not easily come loose in normal release torque due to such with rust with or burn of the male screw 1 is also relatively easily and quickly with a small release torque bolt B ₁ it is possible to loosen the.
That is, when the bolt B ₁ is screwed into the screw hole 11 in advance until the head 13 of the auxiliary bolt 12 is locked to the locking portion 10, the bolt B ₁ and the auxiliary bolt 12 are not tightened. Both are in the state of being extended in the axial direction by the action of tensile force. In this state, if the auxiliary bolt 12 is loosened and removed,
The amount of the tensile force that the auxiliary bolt 12 shared was also changed to the bolt B _1.
There comes to bear tensile force acting on the bolt B ₁ is made to extend the bolt B ₁ by an axial increased. Moreover, the range A where the locking portion 10 and the screw hole portion 11 between That insertion hole 9 is provided, so that at least a part of which is set so as to correspond to the fastened object 4, the locking portion of the bolt B ₁ by between 10 and threaded hole 11 extending in the axial direction, it is possible to reduce the fastening force applied from the bolt B ₁ in the fastened object 4, thereby, the bolt B
Frictional force acting between the _first engaging portion 3 ₁ and the fastened object 4,
And screw holes 6 of the shaft portion 2 ₁ a mount 5 of the bolt B ₁
Will be reduced frictional force acting on the threaded portion of the can loosen the bolt B ₁ easily even at relatively small release torque. Thus the loosening of the bolt B _1, without damaging the fastened object 4 in the work, it is possible to perform easily quickly.

[0014] Moreover fastening aperture 8, which is provided to the bolt B ₁ as a through hole which is open both ends thereof, a screw hole portion 11 so as to be opened by the shaft portion 2 ₁ of the tip side of the bolt B ₁ is axial because provided part 2 _1, it is easy to screw machining.

By the way, when the bolt B ₁ is screwed into the mounting body 5 and tightened, the tightening stress is applied at the screwing start point P ₁ of the male screw 1 to the mounting body 5, that is, at the end of the screw hole 6 on the workpiece 4 side. is made high, the other end i.e. the engaging portion 3 of the bolt B ₁ of screwing start point P ₁ to the mounting body 5 of the male screw 1
Since the screw hole portion 11 is provided continuously to the insertion hole 9 at a position P ₂ shifted to the opposite side of the _1, reduction in the strength of the bolt B ₁ due to the threaded holes 11 in the portion where tightening stress is increased are present Can be prevented.

[0016] Moreover the auxiliary bolts 12, the previously formed material having a higher rigidity and strength compared to the bolt B _1, since it is possible to have the burden of axial force caused by the fastening of the fastened object 4 in the auxiliary bolt 12 , by the action of a large axial force in the bolt B ₁ by loosening the auxiliary bolt 12 by increasing the elongation of the bolt B ₁ and it is possible to further reduce the release torque of the bolt B _1.

FIG. 2 shows a second embodiment of the present invention, in which parts corresponding to those in the first embodiment are denoted by the same reference numerals.

The bolts B _2, the engaging portion 3 at one end of the shaft portion 2 ₂
The nut ₂ is screwed into the shaft 2
The _second end side outer periphery is externally threaded 17 engraved screwing the engaging portion 3 _2, the other end periphery of the shaft portion 2 _2, the male screw 1 to be screwed into the screw hole 6 of the mounting body 5 Engraved.

[0019] The shaft portion 2 ₂ in the bolt B _2, the first embodiment and the fastening hole 8 opened at both ends in the same manner are provided coaxially, the auxiliary bolt 12 inserted into the clamping hole 8 is its head Until the screw holes 13 engage with the locking portions 10.
Advance screwed state, the fastened object 4 by tightening the engaging portion 3 ₂ of the bolt B ₂ is fastened to the mounting body 5 in.

[0020] The second embodiment also, by loosening the auxiliary bolt 12 when loosening the bolts B _2, it is possible to achieve the same descent as the first embodiment.

Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the present invention described in the appended claims. It is possible to do.

[0022] For example a bolt B _1, the engaging portion 3 ₁ of the B _2,
3 fastening aperture 8 threaded hole 11 is provided in _two side may be provided on the bolt B _1, B _2.

[0023]

As described above, according to the present invention, the bolt has an insertion hole portion at least a part of which extends along the axial direction corresponding to the workpiece, and a bolt connected to one end of the insertion hole portion. And one end is connected to the other end of the insertion hole at the other end of the bolt from the point at which the bolt is screwed into the mounting body, and the other end is connected to the outside. And an auxiliary bolt inserted through the insertion hole is inserted into the screw hole until the head of the auxiliary bolt fits into the bolt and engages with the locking portion. screwing advance screwed allowed state, the mounting body bolts through the fastened object to
The bolts and auxiliary bolts
Both bolts are made to work in the axial direction.
Before loosening against the mounting body, attach the auxiliary bolt to the bolt in advance.
By loosening against, Ru can be reduced torque loosen stretched part of the bolt at the portion corresponding to at least the fastened object in the axial direction. In addition to facilitating the threading of the screw holes, it also prevents the screw holes from being present in the areas where the tightening stress increases as the screws are screwed into the mounting body and tightened, thereby preventing the strength of the bolts from decreasing. can do. Further, with the auxiliary bolt screwed into the bolt,
Since the head of the auxiliary bolt is in said bolt, the bolt tightening
The auxiliary bolts do not interfere with the work, and
Is effective in the door of the damage prevention also the growth change in particular bolt
Before giving the shape, screw it with the bolt before tightening it.
When the bolt is tightened, the bolt receives an axial tensile force with the bolt.
Just loosen the auxiliary bolt before loosening the bolt.
The pressurizing means using pressurized fluid is specially installed inside and outside the bolt.
Equipment costs as a whole
And the mobility is very good.
And the work of loosening bolts can be simplified with a relatively small work space.
It can be simply and accurately performed. In addition, the bolt
It is sufficient to simply loosen the auxiliary bolts.
(Eg, the surface of the workpiece) is damaged or dented
There is no fear.

According to the second aspect of the present invention,
The auxiliary bolt is made of a material that is more rigid than the bolt
The main purpose is to reduce the load on the axial
The auxiliary bolt can be held as
When the bolt is loosened, apply sufficient tensile stress to the bolt.
The bolt can be effectively stretched and deformed.
Therefore, the effect of reducing bolt loosening torque is enhanced.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view of a first embodiment.

FIG. 2 is a longitudinal sectional side view of a second embodiment.

[Explanation of symbols]

1 ... external thread 2 _{1, 2} 2 ... shaft portion 3 _1, 3 ₂ ... engaging portion 4 ... fastened object 5 ... mounting body 9 ... insertion hole 10 ... locking portion 11 ... screw hole part 12 ... auxiliary bolt 13 ... head B _1, B ₂ ... bolt

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Haruyuki Watanabe 238 Nakaya Higashi, Gifu City, Gifu Prefecture (72) Inventor Manabu Naoi 3-7, Sohara Shineimachi, Kakamigahara City, Gifu Prefecture (56) References JP-A-5-118314 (JP, a) JP flat 6-42517 (JP, a) JP flat 6-159341 (JP, a) JitsuHiraku Akira 56-143613 (JP, U) (58 ) investigated the field (Int.Cl. ⁷ , DB name) F16B 31/04 F16B 35/00

Claims (2)

(57) [Claims] 1. An object (4) to be fastened between the mounting body (5) and the mounting body (5).
An engaging portion (3 ₁ , 3 ₂ ) for sandwiching a shaft portion (2) having an external thread (1) on its outer periphery screwed to the mounting body (5).
In _1, 2 ₂₎ release torque reduction structure of the bolt to reduce the release torque of the bolt provided at one end (B _1, B ₂₎ of the bolt (B _1, B ₂₎ are, along at least the axial direction insertion hole which is corresponding to a portion of the fastened object (4) and (9), continuous with one end of the insertion hole portion (9) volt (B _1, B ₂₎
And a bolt (B ₁ ,
One end is connected to the other end of the insertion hole (9) at the other end of the bolt (B ₁ , B ₂ ) from the starting point of screwing the B ₂ ) into the mounting body (5). The auxiliary bolt (12) is provided coaxially with a screw hole (11) that is opened outward , and the auxiliary bolt (12) inserted through the insertion hole (9) is connected to the auxiliary bolt (12).
The screw hole portion to the head portion (13) of engaging the bolts (B _1, B ₂₎ in the fit and <br/> the locking portion (10) (1
In a state where the pre-screwed in 1), bolts (B _1, B ₂₎ is of tightening screws in the mounting body (5) through the fastened object (4)
The bolts (B ₁ , B ₂ ) and
Axial tension force acts on both auxiliary bolts (12).
A bolt loosening torque reduction structure, characterized by: 2. The method according to claim 1, wherein said auxiliary bolt (12) is provided with said bolt.
(B ₁ , B ₂ )
The bolt loosening torque reduction according to claim 1, characterized in that:
Construction.