JP2003013930A - Bolt with locking function and bolt and nut with locking function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bolt with locking function and a bolt and nut with locking function having a simple constitution provided with a locking function in the bolt or nut itself requiring no locking action in a separate member. SOLUTION: A constriction 14 having a cylindrical shape with nearly the same diameter with the minor diameter of the male screw 12a formed in the screw part 12 and having a length as long as nearly two pitches of the male screw 12a is formed on the shank 11 of the root side of the screw 12, in a hexagonal bolt 10A in which a screw section 12 is formed at one end side of a shank 11 and a head 13 is formed at the other end side of the shank 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bolt and a bolt nut having a loosening prevention function.

[0002]

2. Description of the Related Art Bolts and nuts (bolt nuts) are widely used as means for connecting and fixing a plurality of members. These bolts and nuts may loosen each other over a long period of use, which may cause an accident, and often requires maintenance such as re-tightening.

The looseness is roughly classified into two types. One of them is caused by the fact that when there is a minute uneven portion or a shape error generated during processing, local plastic deformation progresses due to the influence of external force after tightening and the uneven portion is flattened. Looseness due to sagging of the contact part or fine movement wear. Such looseness is
This occurs even though the nut does not return and rotate. The other is looseness caused by the return rotation of the nut due to the application of vibration or shocking external force. The former type of loosening can be relatively easily prevented by taking measures such as improving the machining accuracy of bolts and nuts or using a material having high wear resistance.
On the other hand, with respect to the latter type of loosening, in most cases, a countermeasure for using a loosening preventing member, that is, a third member other than the bolt nut is used, and the structure is complicated. As a result, there is a problem that durability of the bolt and nut is reduced.

[0004]

As described above, the cause of the looseness caused by the return rotation of the bolt or nut is that the bearing surface pressure of the bolt or nut has a non-axisymmetric distribution and is perpendicular to the axis. It is considered that the nut is subjected to a return rotation action by being subjected to vibration. However, these non-axisymmetric distributions of bearing surface pressure are not only caused by manufacturing errors of the bearing surfaces of bolts and nuts or their contact surfaces, but are also fatal caused by the structure of the bolt and nut itself. It was confirmed by the study by the present inventors. That is, the male screw and the female screw formed on the bolt nut are formed in a spiral and non-axisymmetric shape in terms of their functions, and as a result, the pressure distribution such as the bearing surface pressure also has a non-axisymmetric property. Circumferential distribution is not uniform.

From the above, it is considered that a sufficient loosening prevention effect can be obtained if the pressure on the seat surface can be distributed symmetrically.

The present invention has been made in view of the above circumstances, and it is not necessary to prevent the bolts or nuts from loosening by using a separate member, and the loosening prevention function has a simple structure. An object of the present invention is to provide an attached bolt and a bolt nut with a loosening prevention function.

[0007]

According to a first aspect of the present invention, there is provided a bolt having a loosening preventing function, wherein a screw portion is provided on one end side of the shaft portion and the other end side of the shaft portion is provided. On the base side of the screw part of the bolt provided with the head,
It is characterized in that a constricted portion having a length of about two pitches of the male screw is formed in a cylindrical shape having a diameter substantially the same as the root diameter of the male screw formed on the screw portion.

Further, the invention according to claim 2 is a bolt with a loosening prevention function, wherein the screw part is provided on the root side of the screw part of the bolt having a head on one end side of the screw part. It is characterized in that it has a columnar shape having a diameter substantially the same as the root diameter of the male screw formed in 1. and has a constricted portion having a length of approximately 2 pitches of the male screw.

Further, the invention according to claim 3 is a bolt with a loosening preventive function, wherein a bolt having threaded portions provided on both end sides of a shaft portion is provided on each root side of the threaded portion. It is characterized in that a cylindrical shape having a diameter substantially the same as the root diameter of the male screw formed on each of the screw portions is formed, and a constricted portion having a length of about 2 pitches of each of the male screws is formed. .

Further, the invention according to claim 4 is a bolt nut with a loosening preventing function, wherein a root of one of the threaded parts of a bolt having threaded parts on both ends of the shaft part is provided. A loosening prevention bolt having a columnar shape on the side having a diameter substantially the same as the root diameter of the male screw formed on the threaded portion and having a constricted portion having a height of about 2 pitches of the male screw. , A nut having a bolt insertion hole that is screwed into the other of the threaded portions has a cylindrical inner wall shape having a diameter substantially equal to the root diameter of the internal thread on the seat surface side of the internal thread formed in the bolt insertion hole. And a nut with a loosening prevention function formed by forming a hakama portion having a height of about 2 pitches of the female screw.

Since the constricted portion is formed on the base side of the threaded portion in this manner, the pressure distribution on the seat surface of the nut to be screwed, the contact surface of the member to be fastened, etc. is dispersed to the outer peripheral side, and It can be an axisymmetric distribution. Therefore, the rotational force generated due to the uneven pressure distribution on the seat surface or contact surface can be eliminated and eliminated, and the distribution of the pressure to the outer peripheral side causes friction on the seat surface, contact surface, etc. The resistance moment can be increased. In addition, by forming the constricted portion, the extension of the length increases in tightening, so that an increase in the tightening margin is obtained, and as a result, the difference in the coefficient of thermal expansion between the sag or the bolt and the member to be fastened is obtained. It is possible to accurately prevent loosening caused by the above.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS.

[First Embodiment] First, a first embodiment of the loosening prevention bolt according to the present invention will be described with reference to FIGS. 1 and 2. The present embodiment relates to a hexagon bolt having a loosening prevention function.

The hexagonal bolt (bolt with a loosening preventing function) 10A includes a shaft portion 11 having a male screw 12 formed on one end side, and a hexagonal head in plan view provided on the other end side of the shaft portion 11. And a section 13.

The shaft portion 11 on the base side of the screw portion 12 is formed with a constricted portion 14 having a cylindrical shape having a diameter substantially the same as the root diameter of the male screw 12a formed on the screw portion 12. That is, the constricted portion 14 is a portion where the male screw 12a is not formed, and when the nut 20 is screwed as shown in FIG. 2, the thread of the female screw 22a formed in the bolt insertion hole 22 of the nut 20 is Only the top part of the abuts linearly.

The constricted portion 14 has a length of about two ridges (pitch) of the male screw 12a. Thus, if the length of the constricted portion 14 is set to 2 pitches of the male screw 12a, the seat surface pressure distribution on the seat surface 20a of the nut 20 to be screwed is dispersed to the outer peripheral side of the seat surface 20a, and It can be distributed axisymmetrically. As a result, the action of eliminating and eliminating the rotational force of the nut 20 generated by the uneven distribution of the seat surface pressure and the action of increasing the frictional resistance moment of the seat surface 20a due to the distribution of the seat surface pressure to the outer peripheral side are achieved. A combination of the two actions can provide a sufficient loosening prevention effect. This is what the inventors of the present application have found as a result of their own earnest study.

Further, according to the study by the inventors of the present invention, when the length of the constricted portion is shorter than 2 pitches, for example, about 1 pitch, the seat surface pressure distribution should be axisymmetric. As a result, the seat surface pressure is concentrated on the inner peripheral side, that is, in the vicinity of the portion immediately below the screw, and the bolt or nut rotating action due to the uneven distribution of the seat surface pressure cannot be sufficiently eliminated or eliminated. Conversely, if the length of the constricted portion is longer than 2 pitches, for example, if it is about 4 pitches, then the seat surface pressure will be distributed uniformly over the entire range of the seat surface. As a result, the frictional resistance moment of the seat surface decreases, and it becomes impossible to sufficiently obtain the loosening prevention effect due to the frictional force. Because of this, the constricted portion 1 for achieving a sufficient loosening prevention function.
It can be said that the length of 4 is a length of about 2 pitches of the male screw 12a.

FIG. 2 shows a hexagonal bolt 10A and a nut 2
0 indicates that the members 101 and 102 to be fastened are fastened together and integrally fixed. Fastened member 1
01 and 102 are through-holes 101 penetrating in the thickness direction.
h and 102h, and the head 13 of the hexagonal bolt 10A inserted through these through holes 101h and 102h,
Nut 2 that is screwed into the thread portion 12 of the hexagon bolt 10A
It is sandwiched between 0 and and is integrally connected and fixed.

The pressure distribution on the bearing surface 20a of the nut 20 screwed with the hexagon bolt 10A is such that the constricted portion 14 is formed on the base side of the screw portion 12,
It is distributed on the outer peripheral side and has an axisymmetric distribution. Further, since the seat pressure of the nut 20 is not biased in this way, the head 13 that holds the members 101 and 102 to be fastened together with the nut 20 similarly holds the seat surface 13a. The pressure distribution is axisymmetric.

In this hexagon bolt 10A, the shaft portion 1
1 is provided with a screw portion 12 on one end side and a shaft portion 11 is provided on the other end side with a head portion 13.
Male thread 12a formed on the threaded portion 12 on the base side of 2
The constricted portion 14 having a length of about two pitches of the male screw 12a is formed in a columnar shape having a diameter substantially the same as the root diameter. Therefore, the pressure distribution on the seat surface 20a of the nut 20 to be screwed can be dispersed to the outer peripheral side and can be made axially symmetrical. Further, the seat surface pressure distribution on the seat surface 13a of the head portion 13 can also be an axisymmetric distribution. Therefore, the rotational force generated due to the non-uniform pressure distribution on the seat surface can be eliminated and eliminated, and the friction resistance moment can be increased by distributing the pressure on the seat surface 20a to the outer peripheral side. As a result, both the hexagon bolt 10A and the nut 20 can be prevented from rotating, making it difficult for them to loosen each other. As described above, since the hexagon bolt 10A has the loosening preventing function, it is not necessary to prevent the loosening by using another member, and the hexagonal bolt 10A can be prevented from being loosened accurately while simplifying the structure of the hexagon bolt 10A. it can.

In the above example, the hexagonal bolt is used in combination with the nut, but it may be directly screwed to the member to be tightened without using the nut, that is, it may be used as a holding bolt. An example of the case of being used as the holding bolt will be described with reference to FIG.

FIG. 3 shows a state in which the members 102 and 103 to be fastened are fastened by the hexagonal bolt 10B, and are integrally connected and fixed. Hexagon bolt 10 used here
B differs from the hexagon bolt 10A in that the length of the shaft portion 11 is slightly shortened to be substantially the same as the thickness of the member 102 to be fastened, but the other configurations are the same. Therefore, the same components as those in the hexagon bolt 10A are designated by the same symbols, and detailed description thereof will be omitted.

The tightened member 103 has an internal thread 103 on its inner surface.
It has a bolt insertion hole 103h in which a is formed, and the screw portion 12 of the hexagon bolt 10B is screwed into the bolt insertion hole 103h. The tightened member 102 is
Since the configuration is the same as that described above, description thereof will be omitted.

The pressure distribution on the contact surface 103s of the member 103 to be fastened with which the hexagon bolt 10B is screwed is dispersed to the outer peripheral side because the constricted portion 14 is formed on the base side of the threaded portion 12. , Has an axisymmetric distribution. Further, since the contact surface pressure of the fastened member 103 is not biased in this way, the fastened member 1
Similarly, in the head 13 that holds the member 102 to be fastened together with 03, the pressure distribution on the seat surface 13a has an axially symmetrical distribution.

In the hexagon bolt 10B, the shaft portion 1
1 is provided with a screw portion 12 on one end side and a shaft portion 11 is provided on the other end side with a head portion 13.
Male thread 12a formed on the threaded portion 12 on the base side of 2
The constricted portion 14 having a length of about two pitches of the male screw 12a is formed in a columnar shape having a diameter substantially the same as the root diameter. Therefore, the pressure distribution on the contact surface 103s of the tightened member 103 to be screwed can be dispersed to the outer peripheral side and can be axially symmetrical. Further, the seat surface pressure distribution on the seat surface 13a of the head portion 13 can also be an axisymmetric distribution. Therefore, the rotational force generated due to the uneven pressure distribution on the seat surface or the contact surface is eliminated and eliminated, and the contact surface 103s
The frictional resistance moment can be increased by distributing the pressure at the outer peripheral side. As a result, the hexagon bolt 10B can be prevented from rotating with respect to the tightened member 103, and can be made difficult to loosen. In this way, since the hexagon bolt 10B has the loosening prevention function, it is not necessary to use another member to prevent the loosening.
It is possible to accurately prevent loosening while simplifying the configuration of 0B.

Further, in the above two examples, hexagon bolts are used for the purpose of fastening members to be fastened together, but the present invention is not limited to this, and the members to be fastened are screwed and plugged, that is, It may be used as a stopper bolt. An example of using the stopper bolt as described above will be described with reference to FIG.

FIG. 4 shows a state in which the hexagon bolt 10C is screwed into the tightened member 110 to plug the tightened member 110. The hexagon bolt 10C used here is
Compared with the hexagonal bolts 10A or 10B described above, the only difference is that the shaft portion 11 is not provided, that is, the head portion 13 is provided on the one end side of the screw portion 12, and the other parts have the same configuration. There is. That is, this hexagon bolt 10C
In FIG. 3, a constricted portion 14 is formed on the head portion 13 side which is the base side of the screw portion 12. Therefore, the same reference numerals are assigned to the same constituent elements as those in the hexagon bolts 10A and 10B, and detailed description thereof will be omitted.

The tightening member 110 has an internal thread 110 on its inner surface.
It has a bolt insertion hole 110h in which a is formed, and the screw portion 12 of the hexagonal bolt 10C is screwed into the bolt insertion hole 110h. The member 110 to be fastened contains a liquid or a gas, such as a container or a pipe. Tightened member 11 in the figure
The lower side of 0 is the inside of such a container or pipe. That is, the tightened member 110 is plugged by the hexagon bolt 10C that is integrally fastened.

The pressure distribution on the contact surface 110s of the member 110 to be fastened with which the hexagon bolt 10C is screwed is dispersed to the outer peripheral side because the constricted portion 14 is formed on the base side of the threaded portion 12. , Has an axisymmetric distribution. Further, the pressure distribution in the head portion 13 of the hexagon bolt 10C is also dispersed on the outer peripheral side,
It has an axisymmetric distribution.

In this hexagon bolt 10C, a head portion 13 is provided on one end side of the screw portion 12, and the screw portion 1
Male thread 12a formed on the threaded portion 12 on the base side of 2
The constricted portion 14 having a length of about two pitches of the male screw 12a is formed in a columnar shape having a diameter substantially the same as the root diameter. Therefore, it is possible to disperse the pressure distribution on the contact surface 110s of the member 110 to be screwed to be screwed to the outer peripheral side and to have an axially symmetrical distribution. Furthermore, the seat surface pressure distribution on the seat surface 13a of the head portion 13 can be dispersed to the outer peripheral side and can be an axially symmetrical distribution. Therefore, the rotational force generated due to the non-uniform pressure distribution on the seat surface or the contact surface is eliminated and eliminated, and the friction resistance moment can be increased by distributing the pressure on the outer peripheral side of the contact surface 110s. it can. As a result, the hexagon bolt 10C can be prevented from rotating with respect to the tightened member 110, and can be made difficult to loosen. As described above, since the hexagon bolt 10C has the loosening prevention function, it is not necessary to prevent the loosening by using another member, and the hexagon bolt 10C can be prevented from loosening accurately while simplifying the structure of the hexagon bolt 10C. it can.

[Second Embodiment] Next, a second embodiment of the loosening prevention bolt according to the present invention will be described with reference to FIGS. 5 and 6. The present embodiment relates to an implant bolt having a loosening prevention function. The stud bolt (loosening prevention bolt) 30 is composed of a shaft portion 31 having screw portions 32 and 33 formed on both end sides.

The shaft part 31 on the base side of each of the screw parts 32 and 33 has a cylindrical shape having a diameter substantially the same as the root diameter of the male screw 32a and 33a formed on each of the screw parts 32 and 33. The constricted portions 34 and 35 each having a length of approximately two pitches are formed on each of the male screws 32a and 33a. That is, these constricted portions 34 and 35 are
a and 33a are not formed, and as shown in FIG. 6, when screwed with the nut 40 or the tightened member 103, the female screw 42a formed in the bolt insertion hole 42 of the nut 40, or Only the top portion of the crest of the female screw 103a formed in the bolt insertion hole 103h of the tightened member 103 linearly abuts. That is, the constricted portions 34 and 35 have the same function as the constricted portion 14 in the first embodiment. In addition,
The nut 40 is the nut 20 in the first embodiment.
It has almost the same structure as.

FIG. 6 shows a stud bolt 30 and a nut 40.
Shows that the members 103 and 104 to be fastened are fastened together and integrally connected and fixed. Tightened member 10
3 has a bolt insertion hole 103h having an internal thread 103a formed on the inner surface thereof, and the screw portion 32 of the stud bolt 30 is screwed into the bolt insertion hole 103h. Further, the tightened member 104 has a thickness substantially the same as the length of the shaft portion 31 of the shaft portion 31 sandwiched between the constricted portions 34 and 35, and penetrates in the thickness direction. It has a through hole. The bolt 30 is inserted through the through hole, and the tightened member 104 is sandwiched by the tightened member 103 and the nut 40 screwed with the threaded portion 33 of the implant bolt 30, and integrally formed. It is connected and fixed.

The pressure distribution on the contact surface 103s of the member 103 to be fastened which is screwed with the stud bolt 30 is dispersed to the outer peripheral side by forming the constricted portion 34 on the base side of the screw portion 32. In addition, the distribution is axisymmetric. Further, the pressure distribution on the seat surface 40a of the nut 40 screwed with the stud bolt 30 is also dispersed on the outer peripheral side by forming the constricted portion 35 on the root side of the screw portion 33, and It has an axisymmetric distribution.

In this implant bolt 30, the shaft portion 31
To the shaft portion 31 on the base side of each of the screw portions 32 and 33 of the bolt in which the screw portions 32 and 33 are provided on both end sides of
Male threads 32a, 3 formed on each of the screw parts 32, 33
The constricted portions 34 and 35 having a length of approximately two pitches of the male screws 32a and 33a are formed in a cylindrical shape having a diameter substantially equal to the root diameter of 3a. Therefore, the pressure distribution on both the contact surface 103s of the member 103 to be fastened and the seat surface 40a of the nut 40 to be screwed can be dispersed to the outer peripheral side and can be made axially symmetrical. Therefore, the rotational force generated due to the non-uniform pressure distribution on the seat surface is eliminated and eliminated, and the contact surface 103s and the seat surface 40a are distributed by distributing the pressure to the outer peripheral side.
The frictional resistance moment can be increased. As a result, both the stud bolt 30 and the nut 40 can be prevented from rotating so that they cannot be loosened from each other. As described above, since the stud 30 has the loosening prevention function, it is not necessary to use another member to prevent the slack, and the stud 30 can be prevented from loosening properly while simplifying the structure of the stud 30. be able to.

[Third Embodiment] An embodiment of a bolt nut with a loosening prevention function according to the present invention will be described as a third embodiment with reference to FIGS. 7 and 8. This embodiment is an example in which the present invention is applied to a stud and a nut.

As shown in FIG. 8, the stud bolt nut (bolt nut with loosening prevention function) A has a stud bolt (bolt with loosening prevention function) 50 and a nut (slackness screwed with the stud bolt 50). It is a combination with a nut with prevention function) 60.

The stud bolt 50 has a threaded portion 5 on both end sides.
2 and 53 are formed on the shaft portion 51. The shaft portion 51 on the root side of the screw portion 532 has a columnar shape having a diameter substantially the same as the root diameter of the male screw 52a formed in the screw portion 52, and has a constricted portion having a length of about 2 pitches of the male screw 52a. 54 is formed. That is, the constricted portion 54 is a portion where the male screw 52a is not formed, and is formed in the bolt insertion hole 103h of the joined member 103 when the joined member 103 is screwed as shown in FIG. Only the crest portion of the internal thread 103a comes into linear contact. That is, the constricted portion 54 is the constricted portion 14, 3 in the first and second embodiments.
It has the same function as 4, 35. It should be noted that no constricted portion is formed on the base side of the screw portion 53.

As shown in FIG. 7, the nut 60 has a bolt insertion hole 62 into which the threaded portion 53 of the stud 50 is inserted. A female screw 6 is formed on the inner surface of the bolt insertion hole 62.
2a is formed, and on the lower end side thereof, that is, on the bearing surface 60a side, a hakama having a cylindrical inner wall shape substantially the same as the root diameter of the internal thread 62a and having a length of approximately 2 pitches of the internal thread 62a. The portion 64 is formed. That is, this hakama portion 64 is a portion in which the female screw 62a is not formed, and when the screw portion 53 of the stud 50 is screwed, the male screw 53a formed in the screw portion 53 as shown in FIG.
Only the top of the mountain is in linear contact.
That is, this hakama portion 64 has the same function as the constricted portion 54.

In FIG. 8, the member 1 to be tightened is fixed by the stud bolt A, that is, the stud bolt 50 and the nut 60.
It shows a state in which 03 and 104 are fastened together and integrally connected and fixed. These tightened members 103 and 104 are
Since the configuration is the same as in the second embodiment, the description is omitted. The pressure distribution on the contact surface 103s of the member 103 to be fastened which is screwed with the stud 50 is dispersed to the outer peripheral side due to the constriction 54 formed on the base side of the screw portion 52, and the It has a symmetrical distribution. Further, the pressure distribution on the seat surface 60a of the nut 60 screwed with the stud 50 is also dispersed to the outer peripheral side by forming the hakama 64 on the lower end side of the bolt insertion hole 62. With
It has an axisymmetric distribution.

In this stud bolt nut A, screw parts 52 and 53 are provided on both ends of the shaft part 51, and a male screw formed on the screw part 52 is attached to the shaft part 51 on the base side of the screw part 52. An implant bolt 50 having a columnar shape having a diameter substantially the same as the root diameter of 52a and having a constricted portion 54 having a height of approximately 2 pitches of the male screw 52a, and a screw portion 53.
Has a bolt insertion hole 62 for screwing with
On the seat surface 60a side of the female screw 62a formed on the female screw 62a.
A female screw 6 having a cylindrical inner wall shape having a diameter substantially the same as the root diameter of 2a.
The nut 60 formed by forming the skirt portion 64 having a height of about 2 pitches of 2a is combined. Therefore, the contact surface 103s of the fastened member 103 to be screwed
It is possible to disperse the pressure distribution on both the seat surface 60a of the nut 60 and the bearing surface 60a of the nut 60 on the outer peripheral side and to make the distribution axially symmetrical. Therefore, the rotational force generated due to the non-uniform pressure distribution can be eliminated and eliminated, and the friction resistance moment of the contact surface 103s and the seat surface 60a can be increased by distributing the pressure to the outer peripheral side. . This prevents both the stud bolt 50 and the nut 60 from rotating and makes them difficult to loosen. As described above, since both the studs 50 and the nuts 60 have a loosening prevention function, it is not necessary to prevent the slacks by using separate members, and the studs 50 and the nuts 60 have a simple structure. However, it is possible to accurately prevent loosening.

[0042]

As described above, in the present invention, since the structure as described above is adopted, it is necessary to provide the bolt or nut itself with the loosening preventing function and to prevent the loosening by using another member. It is possible to provide a bolt with a loosening prevention function and a bolt / nut with a loosening prevention function that have a simple structure.

[Brief description of drawings]

FIG. 1 is a view showing a first embodiment of a loosening prevention bolt according to the present invention, in which (a) is a front view,
(B) is a bottom view.

FIG. 2 is a partial cross-sectional view showing a state where a bolt with a loosening prevention function and a nut in FIG. 1 are tightened.

FIG. 3 is a view showing another example of the first embodiment of the loosening prevention bolt according to the present invention, which is a partial cross-sectional view showing a state of tightening the loosening prevention bolt and the member to be fastened. Is.

FIG. 4 is a view showing still another example of the first embodiment of the loosening prevention bolt according to the present invention,
It is a fragmentary sectional view showing the time of tightening a bolt with loosening prevention function, and a member to be fastened.

FIG. 5 is a front view showing a second embodiment of the loosening prevention bolt according to the present invention.

FIG. 6 is a partial cross-sectional view showing a state in which a bolt with a loosening preventing function and a nut in FIG. 5 are tightened.

7A and 7B are views showing an embodiment of a nut with a loosening preventing function, which constitutes a bolt nut with a loosening preventing function according to the present invention, in which FIG. 7A is a partial sectional view and FIG. 7B is a plan view. .

FIG. 8 is a partial cross-sectional view showing an embodiment of a bolt nut with a loosening prevention function according to the present invention.

[Explanation of symbols]

10A, 10B, 10C Hexagonal bolts (bolts, bolts with loosening prevention function) 11 Shaft portion 12 Threaded portion 12a Male screw 13 Head 14 Constriction portion 20 Nut 30 Implant bolt (bolts, bolts with loosening prevention function) 31 Shaft portion 32, 33 screw part 32a, 33a male screw 34, 35 constricted part 40 nut 50 stud bolt (bolt, bolt with loosening prevention function) 51 shaft part 52, 53 screw part 52a, 53a male screw 54 constricted part 60 nut (nut with loosening prevention function ) 60a Seat surface 62 Bolt insertion hole 62a Female screw 64 Hakama part A Implant bolt nut (bolt nut with loosening prevention function)

Claims (4)

[Claims] 1. A bolt having a screw portion provided on one end side of the shaft portion and a head portion provided on the other end side of the shaft portion, formed on the screw portion on the base side of the screw portion. A bolt with a loosening preventing function, which has a columnar shape having a diameter substantially the same as the root diameter of the formed male screw, and has a constricted portion having a length of about 2 pitches of the male screw. 2. A bolt having a head portion provided on one end side of the threaded portion is formed on the base side of the threaded portion with a cylindrical shape having a diameter substantially the same as the root diameter of the male screw formed on the threaded portion. A bolt with a loosening preventing function, wherein a constricted portion having a length of about 2 pitches of the male screw is formed. 3. A bolt having a threaded portion on each end of the shaft portion, and having a diameter substantially the same as the root diameter of the male screw formed on each of the threaded portions on the root side of each of the threaded portions. Make a cylindrical shape,
A bolt with a loosening preventing function, characterized in that a constricted portion having a length of approximately two pitches of each of these male screws is formed. 4. A bolt having thread portions provided on both end sides of a shaft portion and having a diameter substantially the same as a root diameter of a male screw formed on the thread portion on one root side of the thread portion of the bolt. Make a cylindrical shape,
A loosening prevention bolt having a constricted portion having a height of about 2 pitches of the male screw, and a nut having a bolt insertion hole screwed into the other of the screw portions, in the bolt insertion hole. A nut with a loosening prevention function formed on the bearing surface side of the formed internal thread by forming a hakama portion having a cylindrical inner wall shape of substantially the same diameter as the root diameter of the internal thread and having a height of approximately 2 pitches of the internal thread. A bolt nut with a loosening prevention function that is characterized by combining and.