JP4418025B1 - Bolt / Nut Fastener - Google Patents

Abstract

A bolt-and-nut fastening body capable of achieving sufficient prevention of loosening is provided.
A hexagonal nut N is formed with a female screw N3 that is screwed with a male screw B3 of a hexagonal bolt B. An eccentric arc shape is formed on a surface facing the head B1 of the hexagonal bolt B when screwed with the male screw B3. A convex curved surface portion N4 is formed, and a screw cutting portion N5 is formed at a position extending in the axial direction, over a predetermined angle range with respect to the central axis, and symmetrical with respect to the central axis.
[Selection] Figure 2

Description

The present invention relates to a bolt and nut fastening body that fastens a fastened body by screwing a bolt and a nut.

Bolt and nut fasteners are not limited to industrial fields, such as assembly of various structures, installation of various devices, etc., paying attention to simple structure and easy handling, etc. Widely used.
By the way, in the bolt and nut fastening body, the vibration of the bolt is caused by the fact that the screw thread of the bolt is playing in the screw thread of the nut (or the screw thread of the nut is playing in the screw thread of the bolt). When added, it has the major disadvantage of loosening.
In consideration of such drawbacks, in order to suppress loosening, a so-called double nut system in which two nuts are screwed to one bolt has been proposed and actually employed.
However, when the double nut method is adopted, after tightening the two nuts one after the other, with one nut fixed (rotation-prevented), the other nut is connected to one nut. It is necessary to perform the tightening work, and the tightening work becomes complicated.
Also, even when the double nut method is adopted, since the looseness is not completely eliminated, regular inspection is required when using it on a railway vehicle, etc., and maintenance costs increase. .

In consideration of such points, proposals of nuts for preventing loosening have been made (see Patent Document 1, Patent Document 2, Patent Document 3, and Patent Document 4).
Patent Document 1 describes a locking nut having a configuration in which cuts extending in the radial direction from both sides are formed, and an upper portion thereof is plastically deformed and bent downward.
And it is described by this structure that the lower part has a fastening action, the upper part gives a locking load, and these directions can be reversed.
However, the locking nut described in Patent Document 1 forms a notch that reaches the female screw symmetrically about the axis of the nut body, and pushes the upper portion downward so as to reduce the outside of the notch. Is essential and is extremely difficult to manufacture. Specifically, it is almost impossible to deform only the cut portion formed only in a limited range in this way considering that both sides function to prevent the deformation.

Patent Document 2 describes a locking nut having a configuration in which an annular recess is provided on the inner periphery, and the pitch of the thread in this part is smaller than the pitch of the thread in the other part.
And it is described by this structure that a part with a small pitch can deform | transform so that it may become equal to the pitch of another part, a frictional resistance can be raised with the bending force by a deformation | transformation, and loosening prevention can be achieved.
However, the locking nut described in Patent Document 2 can only be manufactured through a complicated manufacturing process, which increases the cost. In addition, since the process of deforming the wall part is included in the middle of the manufacturing process, there is a high possibility that variations in the degree of deformation will occur, and as a result, the expected performance may not be achieved. is there.

Patent Document 3 describes a loosening prevention nut having a nut with a concave portion and a nut with a convex portion, in which the centers of the concave portion and the convex portion are slightly shifted.
And it is described by this structure that the force of the direction orthogonal to the axial center of a volt | bolt acts, and can give the shearing force to the external thread of a volt | bolt, and can improve the locking effect | action of a nut.
However, the loosening prevention nut described in Patent Document 3 requires two nuts, and further, a concave portion is formed on one side and a convex portion is formed on the other, and the center of the concave portion and the convex portion is formed. Since it is necessary to shift it slightly, the configuration becomes complicated and the cost is increased. Moreover, depending on the extent to which the center of a recessed part and a convex part is shifted | deviated, sufficient loosening prevention cannot be achieved or sufficient tightening cannot be performed.

In Patent Document 4, a lower nut part having a fastening surface in contact with a member to be fastened as an inclined surface and an upper nut part of the same size are integrally formed, and a tightening force larger than the fastening force of the lower nut part is provided. This is a Yurumi lock nut which is given to the part and separated from the lower nut part to form a double nut.
With this configuration, the locking effect is improved by fixing in a tilted posture while filling the gap between the screwed portions of the lower nut and the bolt, and there is no need to use two nuts. It is described that the work man-hour of the fastening work can be reduced.
However, in the Yurumi retaining nut described in Patent Document 4, the gap between the bolt and the screw portion, the backlash is as small as about 1/10 of the screw thread, and one screw thread overcomes the other screw thread. Considering that there is nothing, the meshing cannot be strengthened to the extent that sufficient prevention of loosening can be achieved. In addition, a tightening force larger than the tightening force of the lower nut part is applied to the upper nut part to separate it from the lower nut part, resulting in a double nut, so that the meshing surface of the lower nut part and the bolt is separated, and the lower nut Since the screw thread of the bolt may be in a state of swimming in the thread of the part, sufficient prevention of loosening cannot be achieved.

JP 2004-218664 A Japanese Patent Laid-Open No. 06-200916 Japanese Patent Laying-Open No. 2005-048807 JP 2006-010054 A

The problems to be solved by the present invention are as follows.
The first problem to be solved by the present invention is to provide a bolt and nut fastening body that can achieve sufficient prevention of loosening.
The second problem to be solved by the present invention is to provide a bolt and nut fastening body capable of engaging one of screw threads of a bolt and a nut with the other.
The third problem to be solved by the present invention is to provide a bolt and nut fastening body capable of easily engaging one of the bolt and nut threads with the other.
The fourth problem to be solved by the present invention is to provide a bolt and nut fastening body that is simple and easy to manufacture.
The fifth problem to be solved by the present invention is to provide a bolt and nut fastening body that can achieve sufficient loosening prevention and can reliably prevent removal.

Means for solving the problem is the invention described in each claim of [Claims] of the present application.
In order to eliminate the doubts about the interpretation of terms such as claims, description, drawings, etc., the terms will be explained below.
<Explanation of terms>
A bolt is formed by forming a male screw on the surface of a rod-shaped body having a predetermined length. And it may have a head having a diameter larger than that of the rod-shaped body, but the rod-shaped body may be directly integrated with a predetermined fixing portion by welding or the like without having a head. . Further, the outer shape of the head can be an arbitrary polygonal shape such as a quadrangle, a pentagon, or a hexagon.
A nut is a cylindrical body formed by forming a female screw that is screwed with a male screw of a bolt. The outer shape can be any polygonal shape such as a quadrangle, pentagon, or hexagon.
A bolt and nut fastening body is formed by screwing a female screw of a nut into a male screw of a bolt and integrating them.
-A to-be-fastened body is a target object which should be integrated by a bolt nut fastening body, and the hole which can penetrate a volt | bolt is formed.
○ The contact surface at the time of tightening is a surface of the bolt and / or nut that comes into contact with the body to be fastened at the time of tightening.
○ The screw cutting part is a part where there is no screw thread, and may be a part where a part of the screw thread once formed is cut off, or even a part where the screw thread is not formed from the beginning. Good.
The term “tightening end” refers to a period after the most protruding portion or protrusion of the arc-shaped convex curved surface comes into contact with the body to be fastened until the fastening operation is completed.

○ A notch is a hexagonal bolt head, a nut that has been cut off by a flat or curved surface from the original hexagonal shape, or a hexagonal bolt head, a smooth edge of a nut (including straight edges) ) Refers to a locally formed recess (for example, a hole or cut).
The first cutout refers to a portion cut from a natural hexagonal shape of the head of the hexagon bolt and nut and cut by a flat surface and / or a curved surface. As the first notch, for example, the first notch is formed after being cut out in a plane substantially perpendicular to the side of the head of the hexagon bolt at a first predetermined distance from the corner of the head of the hexagon bolt and the nut. The notch part notched by this curved surface can be illustrated.
O A 2nd notch part means the part cut by the plane and / or curved surface from the original hexagonal shape of the head of a hexagon bolt and a nut. As the second notch, for example, a gentle second after being cut out in a plane substantially perpendicular to the side of the head of the hexagon bolt at a second predetermined distance from the corner of the head of the hexagon bolt and the nut. The notch part notched by this curved surface, the head part of a hexagon bolt, and the notch part notched by the gentle curved surface over the predetermined distance range from the corner | angular of a nut can be illustrated.
A protruding portion refers to a portion sandwiched between a first cutout portion and a second cutout portion. And it is preferable that the base part of this protrusion part is provided with the notch part sharp from the 2nd notch part. However, the second cutout itself may be a sharp cutout.

The present inventor has completed the present invention through extensive research in view of the various problems of the above-described conventional technology.
The reason why the present inventor noticed the importance of the problem to be solved by the present invention is that the biggest cause of the drawbacks of the prior art is not only to strengthen the thread engagement but also to bite the thread. I didn't realize the need for it.
The inventor has not only strengthened the engagement of the screw threads but also conducted various studies and searches for the possibility of being able to engage the screw threads, thereby completing the present invention.
Means for solving the problems are the inventions described in the claims of the present application, and specific means for solving the problems are as follows.

-1st invention (Invention of Claim 1)
A first invention for solving the above problems (the invention according to claim 1)
In the bolt and nut fastening body that fastens the fastened body by screwing the bolt and nut,
The contact surface at the time of tightening of the bolt and / or nut that comes into contact with the body to be fastened at the time of tightening is formed as an eccentric arc-shaped convex curved surface,
A thread cut portion is formed so as to extend in the axial direction and over a predetermined angle range with respect to the female screw of the nut and / or the male screw of the bolt,
At the end of tightening, the central axis of the bolt and the central axis of the nut are relatively inclined, and the presence of a screw cut portion makes it possible to engage screws and prevent loosening by this engagement. It is a bolt and nut fastening body.

-Second invention (Invention described in claim 2)
The second invention (the invention according to claim 2) for solving the above problems is as follows.
In the bolt and nut fastening body that fastens the fastened body by screwing the bolt and nut,
The contact surface at the time of tightening of the bolt and / or nut that comes into contact with the body to be fastened at the time of tightening is formed as an eccentric arc-shaped convex curved surface,
The female screw of the nut or the male screw of the bolt is formed in an elliptical shape,
At the end of tightening, the central axis of the bolt and the central axis of the nut are relatively inclined, and the female screw of the nut or the male screw of the bolt is formed in an elliptical shape, so that the screws can be easily caught. It is a bolt and nut fastening body characterized by preventing loosening by biting.

-3rd invention (Invention of Claim 3)
A third invention for solving the above problems (the invention according to claim 3) is as follows:
In the bolt and nut fastening body that fastens the fastened body by screwing the bolt and nut,
A protrusion is formed at a predetermined eccentric position on the contact surface of the bolt and / or nut that comes into contact with the body to be fastened when tightening.
A thread cut portion is formed so as to extend in the axial direction and over a predetermined angle range with respect to the female screw of the nut and / or the male screw of the bolt,
At the end of tightening, the central axis of the bolt and the central axis of the nut are relatively inclined, and the presence of a screw cut portion makes it possible to engage screws and prevent loosening by this engagement. It is a bolt and nut fastening body.

-4th invention (Invention of Claim 4)
A fourth invention for solving the above problems (the invention according to claim 4) is as follows:
In the bolt and nut fastening body that fastens the fastened body by screwing the bolt and nut,
A projecting portion is formed at a predetermined position where the contact surface of the bolt and / or nut that comes into contact with the fastened body at the time of tightening is eccentric.
The female screw of the nut or the male screw of the bolt is formed in an elliptical shape,
At the end of tightening, the central axis of the bolt and the central axis of the nut are relatively inclined, and the female screw of the nut or the male screw of the bolt is formed in an elliptical shape, so that the screws can be easily caught. It is a bolt and nut fastening body characterized by preventing loosening by biting.

○ Fifth invention (Invention according to claim 5)
The fifth invention (the invention according to claim 5) for solving the above problem is as follows.
The bolt is a hexagonal bolt, the nut is a hexagonal nut, and the first notch and the second notch including a sharp notch are provided on the head of the hexagonal bolt and / or each side of the hexagonal nut, When tightening, only the compressive stress acts on the protrusion between the first notch and second notch, and when loosening, the tensile stress due to bending acts on the protrusion. The bolt and nut fastening body according to any one of claims 1 to 4, wherein the head of the hexagonal bolt and / or the hexagonal nut is damaged.

-6th invention (Invention of Claim 6)
According to a sixth invention for solving the above-mentioned problems (the invention according to claim 6), the bolt is a hexagonal bolt, the nut is a hexagonal nut, and the head of the hexagonal bolt and / or each side of the hexagonal nut. By providing the first cutout portion and the second cutout portion including the sharp cutout portion at the time of tightening, a tensile stress due to bending acts on the protruding portion sandwiched between the first cutout portion and the second cutout portion. The bolt according to any one of claims 1 to 4, wherein when a predetermined tightening torque is exceeded, the head of the hexagon bolt and / or the hexagon nut are damaged from the sharp notch. It is a nut fastening body.

The bolt and nut fastening body according to the present invention is composed of the above characteristic constituent elements and has the following effects specific to the present invention according to the characteristic constituent elements.
Moreover, according to the bolt and nut fastening body constituted from the above characteristic constituent requirements, the problem of the present invention could be solved.
○ Effect of the first invention According to the first invention,
In the bolt and nut fastening body that fastens the fastened body by screwing the bolt and nut,
The contact surface at the time of tightening of the bolt and / or nut that comes into contact with the body to be fastened at the time of tightening is formed as an eccentric arc-shaped convex curved surface,
A thread cut portion is formed so as to extend in the axial direction and over a predetermined angle range with respect to the female screw of the nut and / or the male screw of the bolt,
At the end of tightening, the central axis of the bolt and the central axis of the nut are relatively inclined, and there is a screw cutting part, so that the screws are engaged with each other and loosening is prevented by this engagement. Depending on requirements
A bolt and nut fastening body capable of effectively preventing loosening can be provided.
That is, the first problem, the second problem, and the fourth problem to be solved by the present invention can be achieved, and a remarkable effect that cannot be predicted by those skilled in the art can be achieved.

○ Effect of the second invention According to the second invention,
In the bolt and nut fastening body that fastens the fastened body by screwing the bolt and nut,
The contact surface at the time of tightening of the bolt and / or nut that comes into contact with the body to be fastened at the time of tightening is formed as an eccentric arc-shaped convex curved surface,
The female screw of the nut or the male screw of the bolt is formed in an elliptical shape,
At the end of tightening, the central axis of the bolt and the central axis of the nut are relatively inclined, and the female screw of the nut or the male screw of the bolt is formed in an elliptical shape, so that the screws can be easily caught. Due to the characteristic configuration requirement to prevent loosening by biting,
A bolt and nut fastening body capable of effectively preventing loosening can be provided.
That is, the first problem, the third problem, and the fourth problem to be solved by the present invention can be achieved, and a remarkable effect that cannot be predicted by those skilled in the art can be achieved.

○ Effect of the third invention According to the third invention,
In the bolt and nut fastening body that fastens the fastened body by screwing the bolt and nut,
A protrusion is formed at a predetermined eccentric position on the contact surface of the bolt and / or nut that comes into contact with the body to be fastened when tightening.
A thread cut portion is formed so as to extend in the axial direction and over a predetermined angle range with respect to the female screw of the nut and / or the male screw of the bolt,
At the end of tightening, the central axis of the bolt and the central axis of the nut are relatively inclined, and there is a screw cutting part, so that the screws are engaged with each other and loosening is prevented by this engagement. Depending on requirements
A bolt and nut fastening body capable of effectively preventing loosening can be provided.
That is, the first problem, the second problem, and the fourth problem to be solved by the present invention can be achieved, and a remarkable effect that cannot be predicted by those skilled in the art can be achieved.

○ Effect of the fourth invention According to the fourth invention,
In the bolt and nut fastening body that fastens the fastened body by screwing the bolt and nut,
A projecting portion is formed at a predetermined position where the contact surface of the bolt and / or nut that comes into contact with the fastened body at the time of tightening is eccentric.
The female screw of the nut or the male screw of the bolt is formed in an elliptical shape,
At the end of tightening, the central axis of the bolt and the central axis of the nut are relatively inclined, and the female screw of the nut or the male screw of the bolt is formed in an elliptical shape, so that the screws can be easily caught. Due to the characteristic configuration requirement to prevent loosening by biting,
A bolt and nut fastening body capable of effectively preventing loosening can be provided.
That is, the first problem, the third problem, and the fourth problem to be solved by the present invention can be achieved, and a remarkable effect that cannot be predicted by those skilled in the art can be achieved.

○ Effect of the fifth invention According to the fifth invention,
The bolt is a hexagonal bolt, the nut is a hexagonal nut, and the first notch and the second notch including a sharp notch are provided on the head of the hexagonal bolt and / or each side of the hexagonal nut, When tightening, only the compressive stress acts on the protrusion between the first notch and second notch, and when loosening, the tensile stress due to bending acts on the protrusion. Due to the characteristic component requirement that the hex bolt head and / or hex nut is damaged,
It has been possible to provide a bolt-and-nut fastening body that can effectively prevent loosening and that can reliably prevent artificial loosening and removal.
That is, the fifth problem to be solved by the present invention can be achieved, and a remarkable effect that cannot be predicted by those skilled in the art can be achieved.

○ Effect of the sixth invention According to the sixth invention,
The bolt is a hexagonal bolt, the nut is a hexagonal nut, and the first notch and the second notch including a sharp notch are provided on the head of the hexagonal bolt and / or each side of the hexagonal nut, At the time of tightening, a tensile stress due to bending acts on the protruding part sandwiched between the first notch part and the second notch part. When a predetermined tightening torque is exceeded, the head of the hexagon bolt is removed from the sharp notch part. Due to the characteristic component requirement that parts and / or hex nuts are damaged,
It has been possible to provide a bolt-and-nut fastening body that can effectively prevent loosening and that can reliably prevent artificial loosening and removal.
That is, the fifth problem to be solved by the present invention can be achieved, and a remarkable effect that cannot be predicted by those skilled in the art can be achieved.

It is a schematic front view which shows one Embodiment of the bolt nut fastening body of this invention. It is the schematic which shows one Embodiment of a nut, (A) represents the schematic plan view, (B) represents the schematic front view. It is the schematic which shows one Embodiment of a volt | bolt, (A) represents a schematic plan view, (B) represents the schematic front view. It is a schematic plan view which shows other embodiment of a volt | bolt nut fastening body. It is a schematic plan view which shows other embodiment of a volt | bolt nut fastening body. It is a principal part enlarged plan view which shows other embodiment of a nut. It is a principal part enlarged plan view which shows other embodiment of a volt | bolt.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a bolt and nut fastening body of the present invention will be described in detail with reference to the accompanying drawings.
The bolt and nut fastener of the first invention is:
In the bolt and nut fastening body that fastens the fastened body h by screwing the bolt B and the nut N,
The tightening contact surface of the bolt B and / or the nut N that comes into contact with the fastened body h at the time of tightening is formed on the eccentric arc-shaped convex curved surfaces B4 and N4.
The thread cut portions N5 and B5 are formed so as to extend in the axial direction and over a predetermined angle range with respect to the female thread N3 of the nut N and / or the male thread B3 of the bolt B,
At the end of tightening, the central axis of the bolt B and the central axis of the nut N are relatively inclined, and the screw cut portions N5 and B5 are present, so that the screws are engaged with each other and loosening is prevented by this engagement. It is characterized by that.

The bolt and nut fastener of the second invention is
In the bolt and nut fastening body that fastens the fastened body h by screwing the bolt B and the nut N,
The tightening contact surface of the bolt B and / or the nut N that comes into contact with the fastened body h at the time of tightening is formed on the eccentric arc-shaped convex curved surfaces B4 and N4.
The internal thread N3 of the nut N or the external thread B3 of the bolt B is formed in an elliptical shape,
At the end of tightening, the central axis of the bolt B and the central axis of the nut N are relatively inclined, and the internal thread N3 of the nut N or the external thread B3 of the bolt B is formed in an elliptical shape. It is characterized by being easy to incorporate and preventing loosening by this engagement.

The bolt and nut fastener of the third invention is
In the bolt and nut fastening body that fastens the fastened body h by screwing the bolt B and the nut N,
A protrusion is formed at a predetermined position on the contact surface of the bolt B and / or nut N that is in contact with the fastened body h at the time of tightening.
The thread cut portions N5 and B5 are formed so as to extend in the axial direction and over a predetermined angle range with respect to the female thread N3 of the nut N and / or the male thread B3 of the bolt B,
At the end of tightening, the central axis of the bolt B and the central axis of the nut N are relatively inclined, and the screw cut portions N5 and B5 are present, so that the screws are engaged with each other and loosening is prevented by this engagement. It is characterized by that.

The bolt and nut fastener of the fourth invention is:
In the bolt and nut fastening body that fastens the fastened body h by screwing the bolt B and the nut N,
A protrusion is formed at a predetermined position on the contact surface of the bolt B and / or nut N that is in contact with the fastened body h at the time of tightening.
The internal thread N3 of the nut N or the external thread B3 of the bolt B is formed in an elliptical shape,
At the end of tightening, the central axis of the bolt B and the central axis of the nut N are relatively inclined, and the internal thread N3 of the nut N or the external thread B3 of the bolt B is formed in an elliptical shape. It is characterized by being easy to incorporate and preventing loosening by this engagement.

The bolt and nut fastener of the fifth invention is
The bolt B is a hexagon bolt, the nut N is a hexagon nut, and includes a first notch B11 and a sharp notch Bs33 on each side of the head B1 and / or the hexagon nut N of the hexagon bolt B. By providing the notch B22, when tightening, only the compressive stress acts on the projection B33 sandwiched between the first notch B11 and the second notch B22, and when loosened, the tensile stress due to bending causes the projection. The head B1 and / or the hex nut N of the hexagon bolt B is damaged from the sharp notch Bs33 so as to act on B33.

In the bolt and nut fastening body according to the sixth aspect of the invention, the bolt B is a hexagonal bolt, the nut N is a hexagonal nut, and a first notch B11 is formed on each side of the head B1 and / or the hexagonal nut N of the hexagonal bolt B. By providing the second notch B22 including the sharp notch Bs33, a tensile stress due to bending acts on the protrusion B33 sandwiched between the first notch B11 and the second notch B22 when tightening. The head B1 and / or the hexagon nut N of the hexagon bolt B is damaged from the sharp notch Bs33 when a predetermined tightening torque is exceeded.

FIG. 1 is a schematic front view showing an embodiment of a bolt and nut fastener of the present invention.
FIG. 2 is a schematic view showing an embodiment of a nut, (A) is a schematic plan view, and (B) is a schematic front view.
FIG. 3 is a schematic plan view showing an embodiment of a bolt, (A) shows a schematic plan view, and (B) shows a schematic front view.
FIG. 4 is a schematic plan view showing another embodiment of a bolt and nut fastening body.
FIG. 5 is a schematic plan view showing still another embodiment of a bolt and nut fastening body.
FIG. 6 is an enlarged plan view of the main part showing still another embodiment of the nut.
FIG. 7 is an enlarged plan view of a main part showing still another embodiment of the bolt.

As shown in FIG. 1, the bolt and nut fastening body includes a hexagon bolt B and a hexagon nut N.
The hexagon bolt B has a hexagonal head portion B1 and a shaft portion B2 on which a male screw B3 is formed.
The hexagon nut N is formed with a female screw N3 that is screwed with the male screw B3. As shown in FIG. 2B, an eccentric arc-shaped convex curved surface portion N4 is formed on the surface facing the head B1 in a state of being screwed with the male screw B3. Further, as shown in FIG. 2A, screw cut portions N5 are formed in the axial direction, over a predetermined angular range with respect to the central axis, and at positions symmetrical to each other with respect to the central axis. Yes.
In addition, it is preferable that the hexagon nut N has an inclined surface that is opposite to the surface on which the eccentric arc-shaped convex curved surface portion N4 is formed, as indicated by a one-dot chain line in FIG.
Further, the height of the eccentric arc-shaped convex curved surface portion N4 may be high, but it may be less than two threads, but it is less than one thread and about 0.5 threads. Is preferred.
The effect | action at the time of fastening a to-be-fastened body using the volt | bolt nut fastening body of said structure is as follows.
A hexagonal bolt B is mounted so as to pass through the hole of the body h to be fastened, and in this state, the hexagonal nut N is screwed into the hexagonal bolt B and is screwed so that the eccentric arc-shaped convex curved surface portion N4 is covered. Contact the fastening body h.
If the hexagon nut N continues to be turned thereafter, the eccentric arc-shaped convex curved surface portion N4 is strongly pressed against the fastened body h, so that the center axis of the hexagon nut N is inclined with respect to the center axis of the hexagon bolt B. In addition, since the screw cutting portion N5 formed on the hexagon nut N is affected, the female screw N3 of the hexagon nut N is engaged with the male screw B3 of the hexagon bolt B.
As a result, loosening of the hexagon nut N can be effectively prevented.
And when the hexagon nut N has the structure shown with a dashed-dotted line in FIG. 1, it can be made into the state which is not inclining the surface of the side away from the to-be-fastened body at the time of completion | finish of fastening.

Further explanation will be given.
Compared with the presence of the screw cutting portion N5 in the female screw N3 and the presence of the eccentric arc-shaped convex curved surface portion N4 because the tightening force by a tightening tool such as a spanner is larger than the strength of the screw thread. It is possible to cause biting easily.
Here, when the ratio of the thread cut portion N5 in the female screw N3 is increased, the engagement is easily generated, and when the ratio is decreased, the engagement is less likely to be generated. On the other hand, when the ratio of the screw cut portion N5 in the female screw N3 is increased, the biting force is decreased, and when the ratio is decreased, the biting force is increased.
That is, biting occurs in a wide range of the ratio of the thread cut portion N5 in the female screw N3, but an appropriate ratio of the screw cut portion N5 in the female screw N3 can be experimentally obtained according to the material and size of the hex nut N. preferable. As an example, it can be exemplified that the screw cut portion N5 has an angle range of 45 ° to 60 °.

In the above embodiment, the hexagon nut N is formed with the screw cut portion N5 and the eccentric arc-shaped convex curved surface portion N4. However, as shown in FIG. It is possible to form the arc-shaped convex curved surface portion B4.
Also in this case, due to the inclination of the central axis and the influence of the screw cutting part B5, the male screw B3 of the hexagon bolt B is engaged with the female screw N3 of the hexagon nut N or the female screw N3 formed on the fastened body h itself. The loosening of B can be effectively prevented.
Instead of the eccentric arc-shaped convex curved surface portion B4 or the eccentric arc-shaped convex curved surface portion N4, it is possible to employ a protruding portion provided at an eccentric predetermined position, and achieve the same effect. it can.

FIG. 4 is a schematic plan view showing another embodiment of a bolt and nut fastening body.
The hexagonal nut N in this embodiment is different from the hexagonal nut N of FIG. 2 only in that an elliptical female screw N3 is formed instead of forming the screw cutting portion N5.
When this embodiment is adopted, a predetermined range corresponding to the long diameter of the elliptical female screw N3 does not mesh with the male screw B3, so that the same function as the screw cutting part N5 is exhibited.
As a result, loosening of the hexagon nut N can be effectively prevented.
FIG. 5 is a schematic plan view showing still another embodiment of a bolt and nut fastening body.
The hexagonal bolt B in this embodiment is different from the hexagonal bolt B in FIG. 3 only in that an elliptical male screw B3 is formed instead of forming the screw cutting portion B5.
When this embodiment is adopted, a predetermined range corresponding to the short diameter of the elliptical male screw B3 does not mesh with the female screw N3, so that the same function as the screw cutting part B5 is exhibited.
As a result, loosening of the hexagon bolt B can be effectively prevented.

FIG. 6 is an enlarged plan view of a main part showing a hexagon bolt B of still another embodiment.
This hexagonal bolt B extends in a direction away from the corner Bp after being cut out by a plane Bs11 approximately perpendicular to the side from a position loosened by a predetermined distance from the corner Bp of the head B1 (counterclockwise direction). A first cutout B11 cut out by a gentle curved surface Bs12 is formed. In addition, a second cutout portion B22 is formed which is cut out from the corner Bp with a gently curved surface Bs22 in the tightening direction (clockwise direction). A sharp notch Bs33 is formed from the second notch B22 at the base of the projection B33 sandwiched between the first notch B11 and the second notch B22. The gentle curved surface Bs12 and the sharp notch Bs33 are formed along the circumference of a circle inscribed in the head of the hexagon bolt B, and the thin broken line in FIG. 6 is broken so as to break along the circumference. It is preferable to make a shallow notch in the portion Ba33.
When the hexagonal bolt B having the above-described configuration is employed, only the compressive stress acts on the protruding portion B33 when tightening using a box wrench or the like, so that sufficient tightening can be achieved and conversely loosened. At that time, since the tensile stress due to bending acts on the projection B33 and the stress is concentrated on the sharp notch Bs33, the head of the hexagon bolt B is damaged from the sharp notch Bs33, and a box wrench or the like Can be reliably prevented from loosening the hexagon bolt B. That is, it is possible to reliably prevent the hexagon bolt B from being loosened due to mischief or the like.
As a result, the hexagon bolt B can be kept in the loosened state.
The configuration similar to that shown in FIG. 6 can be applied to the hex nut, which is suitable for a case where the hex nut is screwed directly to a bolt integrated into a predetermined fixing portion without having a head.
In this case, it is possible to reliably prevent the hexagon nut from being loosened due to mischief or the like, and as a result, it is possible to keep the hexagon nut from being loosened.
Also, it is particularly suitable for applications that do not need to be removed semi-permanently, such as assembling structures, and it is possible to realize a fastening structure and a connecting structure that conform to welding and rivets. Inspection work can be omitted, and maintenance costs can be reduced.

FIG. 7 is an enlarged plan view of a main part showing a hexagon bolt B of still another embodiment.
The hexagon bolt B is cut out by a gentle curved surface Bs12 extending in a direction away from the corner Bp after being cut out by a plane Bs11 substantially perpendicular to the side from a position away from the corner Bp by a predetermined distance in the tightening direction (clockwise direction). A first cutout B11 is formed. Further, a second notch B22 is formed which is notched by a curved surface Bs22 that is loose in the loosening direction (counterclockwise direction) from the corner Bp. A sharp notch Bs33 is formed from the second notch B22 at the base of the projection B33 sandwiched between the first notch B11 and the second notch B22. The gentle curved surface Bs12 and the sharp notch Bs33 are formed along the circumference of a circle inscribed in the head of the hexagon bolt B, and the thin broken line in FIG. 7 is broken so as to break along the circumference. It is preferable to make a shallow notch in the portion Ba33.
When the hexagonal bolt B having the above configuration is used, a tensile stress acts on the protruding portion B33 when tightening with a box wrench or the like. If the tightening torque is sufficiently increased at the end of tightening, a sharp notch Since stress concentrates on the portion Bs33, the head of the hexagon bolt B is damaged from the sharp notch Bs33, and it is possible to reliably prevent the hexagon bolt B from being loosened using a box wrench or the like. That is, it is possible to reliably prevent the hexagon bolt B from being loosened due to mischief or the like.
As a result, the hexagon bolt B can be kept in the loosened state.
The configuration similar to that shown in FIG. 7 can be applied to the hexagon nut, which is suitable for a case where the hexagon nut is directly screwed into a bolt integrated with a predetermined fixing portion without having a head.
In this case, it is possible to reliably prevent the hexagon nut from being loosened due to mischief or the like, and as a result, it is possible to keep the hexagon nut from being loosened.
In addition, it is particularly suitable for applications that do not need to be removed semi-permanently, such as assembling structures, and it is possible to realize a fastening structure and a connecting structure that conforms to welding and rivets, so that regular operations that are implemented from a safety standpoint are possible. Inspection work can be omitted, and maintenance costs can be reduced.

In the embodiment of FIGS. 6 and 7, a sharp notch is formed at the base of the protruding portion in addition to the second notch that is notched with a gently curved surface. Instead of the notched portion cut out by a gently curved surface, a sharp notched portion can be used. In this case, the configuration can be simplified, and the embodiment shown in FIGS. The same effect can be achieved.

B Hexagon bolt B1 Head B2 Shaft B3 Male screw B4 Eccentric arcuate convex curved surface B5 Screw cutout Bp Angle B11 First cutout Bs11 Plane Bs12 substantially perpendicular to the side Bently curved B22 Second cutout Bs22 Slowly curved B33 Projection part Bs33 Sharp notch N Hexagon nut N3 Female thread N4 Eccentric arcuate curved surface N5 Thread cutting part h Fastened body

Claims (6)

In the bolt and nut fastening body for fastening the fastened body (h) by screwing the bolt (B) and the nut (N),
The tightening contact surface of the bolt (B) and / or nut (N) that contacts the body to be fastened (h) during tightening is formed as an eccentric arc-shaped convex curved surface (B4) (N4),
A thread cut portion (N5) (B5) is formed to extend in the axial direction and over a predetermined angular range with respect to the female thread (N3) of the nut (N) and / or the male thread (B3) of the bolt (B). And
At the end of tightening, the center axis of the bolt (B) and the center axis of the nut (N) are relatively inclined, and the screw cutting part (N5) (B5) is present, so that the screws are engaged with each other. Bolt and nut fastening body characterized by preventing loosening by biting. In the bolt and nut fastening body for fastening the fastened body (h) by screwing the bolt (B) and the nut (N),
The tightening contact surface of the bolt (B) and / or nut (N) that contacts the body to be fastened (h) during tightening is formed as an eccentric arc-shaped convex curved surface (B4) (N4),
The internal thread (N3) of the nut (N) or the external thread (B3) of the bolt (B) is formed in an elliptical shape,
At the end of tightening, the central axis of the bolt (B) and the central axis of the nut (N) are relatively inclined, and the internal thread (N3) of the nut (N) or the external thread (B3) of the bolt (B) A bolt-and-nut fastening body that makes it easy to engage screws with each other and prevents loosening by this engagement. In the bolt and nut fastening body for fastening the fastened body (h) by screwing the bolt (B) and the nut (N),
Projections are formed at predetermined eccentric positions on the contact surface of the bolt (B) and / or nut (N) that are in contact with the body to be fastened (h) when tightening.
A thread cut portion (N5) (B5) is formed to extend in the axial direction and over a predetermined angular range with respect to the female thread (N3) of the nut (N) and / or the male thread (B3) of the bolt (B). And
At the end of tightening, the center axis of the bolt (B) and the center axis of the nut (N) are relatively inclined, and the screw cutting part (N5) (B5) is present, so that the screws are engaged with each other. Bolt and nut fastening body characterized by preventing loosening by biting. In the bolt and nut fastening body for fastening the fastened body (h) by screwing the bolt (B) and the nut (N),
Projections are formed at predetermined eccentric positions on the contact surface of the bolt (B) and / or nut (N) that are in contact with the body to be fastened (h) when tightening.
The internal thread (N3) of the nut (N) or the external thread (B3) of the bolt (B) is formed in an elliptical shape,
At the end of tightening, the central axis of the bolt (B) and the central axis of the nut (N) are relatively inclined, and the internal thread (N3) of the nut (N) or the external thread (B3) of the bolt (B) A bolt-and-nut fastening body that makes it easy to engage screws with each other and prevents loosening by this engagement. The bolt (B) is a hexagonal bolt, the nut (N) is a hexagonal nut, and a first notch (B11) is formed on each side of the head (B1) and / or the hexagonal nut (N) of the hexagonal bolt (B). ) And the second cutout portion (B22) including the sharp cutout portion (Bs33), and at the time of tightening, the protruding portion (B33) sandwiched between the first cutout portion (B11) and the second cutout portion (B22) ) So that only compressive stress acts on it, and when it is loosened, tensile stress due to bending acts on the protruding portion (B33), so that the sharp notch (Bs33) to the head of the hexagon bolt (B) (B1) And / or the hexagonal nut (N) is damaged. The bolt (B) is a hexagonal bolt, the nut (N) is a hexagonal nut, and a first notch (B11) is formed on each side of the head (B1) and / or the hexagonal nut (N) of the hexagonal bolt (B). ) And a sharp notch (the second notch (B22) including Bs33), so that at the time of tightening, the protruding part (B33) sandwiched between the first notch (B11) and the second notch (B22) When a predetermined tightening torque is exceeded so that a tensile stress due to bending acts on the head, the head (B1) of the hexagon bolt (B) and / or the hexagon nut (N) from the sharp notch (Bs33) The bolt and nut fastening body according to any one of claims 1 to 4, wherein the bolt and nut are damaged.

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