JP2013130254A - Coming-off stopper, fastening method and fastening structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent coming-off of a male screw body in a fastening structure, and to prevent falling-off, loosening and the like of a nut.SOLUTION: A coming-off stopper 1 has a through hole 2 at the center part, and is not continuous over the entire circumference surrounding the through hole 2 by a cut 3. An inner circumference of the through hole 2 is formed with a thread 4 of a female screw of one thread for approximately one pitch. If the thread 4 of the female screw is relatively pressed in the axial direction by a surface vertical to the axial direction while it is screwed with a root of the male screw part of the male screw body, the thread 4 of the female screw on one end side goes over a thread of the male screw part from the root of the male screw part and intrudes into a part shifted axially by approximately one pitch of the root of the male screw part, so that the thread 4 of the female screw as a whole takes a non-helical shape lying astride the thread of the male screw part, thus achieving prevention of coming-off of the male screw body, prevention of falling-off of the nut, and prevention of loosening of the nut.

Description

  The present invention relates to a stopper, a fastening method, and a fastening structure, and more particularly, to a stopper, a fastening method, and a fastening structure for preventing a male screw body such as a bolt and a small screw from coming out from a fastened body in the fastening structure.

  Conventionally, as a simple method for preventing a male screw body such as a bolt or a small screw from coming off from a body to be fastened in a fastening structure, a method of crushing a tip portion of a shaft portion of the male screw body after fastening is known. Yes.

  Patent Document 1 proposes a retaining washer made of an elastic plate such as nylon and provided with an appropriate number of small semicircular holes at regular intervals around the central large circular hole.

  Furthermore, conventionally, a number of devices for preventing looseness in a fastening structure having a generally ring shape and having an internal thread on the inner periphery have been proposed (for example, Patent Documents 2 and 3). These anti-loosening prevention tools increase the frictional force acting on the male screw body by pressing the internal thread of the inner screw against the male screw portion of the male screw body due to the elasticity of the anti-loosening prevention device itself. It is intended to prevent loosening.

Japanese Utility Model Publication No. 58-116812 Japanese Utility Model Publication No. 2-69111 Japanese Patent Application Laid-Open No. 55-115613

  However, the above-described retaining method for crushing the tip of the shaft portion of the male screw body after tightening has a problem that the fastening structure cannot be disassembled thereafter.

  The retaining washer proposed in Patent Document 1 is provided with an annular groove at an axial position corresponding to the thickness of the fastened body in the shaft portion of the male screw body, and the annular groove. Since it is necessary to fit the vicinity of the inner periphery of the large circular hole, a general-purpose male screw body cannot be used, and there is a problem that the cost of the male screw body increases.

  In addition, the anti-loosening prevention device having a generally ring shape and having an internal thread on the inner periphery has the maximum elastic force that can be generated by such a ring member in the first place. However, no matter how devised their structure, there was a problem that a sufficient locking effect could not be obtained.

  Further, the anti-loosening prevention tool having a generally ring shape and having an internal thread on the inner periphery may loosen in the same manner as a normal nut and fall off from the external thread body, so that an anti-separation preventing effect is obtained. There was no problem.

  Furthermore, the loosening prevention device having a generally ring shape and having an internal thread on the inner periphery must be screwed onto the external thread body outside the nut, and is interposed between the nut and the body to be fastened. The function as a washer could not be fulfilled.

  The present invention has been made in view of the above-described conventional circumstances, and one of the objects of the present invention is to prevent the male screw body in the fastening structure from coming off, and when necessary, to prevent it from coming off. An object of the present invention is to provide a retainer, a fastening method, and a fastening structure that can be released and disassemble the fastening structure.

  Another object of the present invention is to provide a retainer, a fastening method, and a fastening structure capable of retaining the male screw body without subjecting the male screw body such as a bolt and a small screw to any special processing. It is in.

  Another object of the present invention is to provide a retainer, a fastening method, and a fastening structure capable of preventing the nut from falling off and preventing the nut from loosening.

  Another object of the present invention is to provide a retainer, a fastening method, and a fastening structure that are interposed between a nut and a body to be fastened to prevent the male screw body from coming off and at the same time serve as a washer. It is to provide.

  Another object of the present invention is to provide a retainer, a fastening method, and a fastening structure that do not use a nut and can be attached to a male screw body alone to prevent the male screw body from coming off.

  Still other objects of the present invention will become apparent from the following description.

The retaining tool of the present invention according to claim 1 is a
A retaining device attached to a male screw body having a shaft portion provided with a male screw portion on the outer periphery,
A through hole provided in a central portion, a break from the outer periphery to the through hole, which prevents the retaining tool from surrounding the through hole and continuing over the entire circumference; and the through hole And a thread of one female thread for approximately one pitch formed on the inner periphery of
In a state where the thread of the female screw is screwed into the valley of the male screw portion of the male screw body, when pressed relatively in the axial direction by a surface perpendicular to the axial direction of the female screw and the male screw portion, The thread of the female screw on one end side passes over the thread of the male screw part from the valley of the male screw part and enters a portion shifted in the axial direction by approximately one pitch of the valley of the male screw part, The screw thread is non-spiral as a whole and is in a state of straddling the thread of the male screw part.

The fastening method of the present invention according to claim 7 is:
A through hole provided in a central portion, a break from the outer periphery to the through hole, which prevents the retaining tool from surrounding the through hole and continuing over the entire circumference; and the through hole And a thread of a female thread of approximately one pitch for one pitch formed on the inner circumference of the male thread, and the thread of the female thread is screwed into a valley of the male thread portion provided on the outer circumference of the shaft portion of the male screw body. In this state, when the female screw and the male screw part are relatively pressed in the axial direction by a surface perpendicular to the axial direction of the female screw part, the screw thread of the female screw on one end side is removed from the valley of the male screw part. Overcoming the thread of the male thread part and entering a portion of the valley of the male thread part that is displaced in the axial direction by approximately one pitch, the thread of the female thread becomes non-spiral as a whole and the thread of the male thread part It is supposed to be in a state that straddles And the step of providing a stop missing,
Inserting the shaft portion of the male screw body into the fastened body;
A step of screwing a nut into a male screw portion provided on an outer periphery of the shaft portion of the male screw body, and tightening the fastened body between the nut and the head of the male screw body;
The thread of the female screw of the retainer is screwed into the valley of the male thread portion of the male screw body, and the retainer is pressed against the end surface of the nut opposite to the body to be fastened. The retainer is rotated relative to the tightening direction, and the thread of the female screw on one end side of the retainer passes over the thread of the male thread from the trough of the male thread. Entering a portion shifted in the axial direction by approximately one pitch of the inner thread so that the thread of the female thread is non-spiral as a whole and straddles the thread of the male thread. Is provided.

Further, the fastening method of the present invention according to claim 8 is:
A through hole provided in a central portion, a break from the outer periphery to the through hole, which prevents the retaining tool from surrounding the through hole and continuing over the entire circumference; and the through hole And a thread of a female thread of approximately one pitch for one pitch formed on the inner circumference of the male thread, and the thread of the female thread is screwed into a valley of the male thread portion provided on the outer circumference of the shaft portion of the male screw body. In this state, when the female screw and the male screw part are relatively pressed in the axial direction by a surface perpendicular to the axial direction of the female screw part, the screw thread of the female screw on one end side is removed from the valley of the male screw part. Overcoming the thread of the male thread part and entering a portion of the valley of the male thread part that is displaced in the axial direction by approximately one pitch, the thread of the female thread becomes non-spiral as a whole and the thread of the male thread part It is supposed to be in a state that straddles And the step of providing a stop missing,
Inserting the shaft portion of the male screw body into the fastened body;
The thread of the female screw of the retaining device is screwed into the valley of the male screw portion provided on the outer periphery of the shaft portion of the male screw body, the retaining device is rotated relatively in the tightening direction, Bringing a stopper into contact with the fastened body;
A nut is screwed into the male screw portion of the male screw body, the fastened body and the stopper are tightened between the nut and the head of the male screw body, and the female screw on one end side of the stopper The thread of the male screw passes over the thread of the male screw part from the valley of the male screw part and enters a portion shifted in the axial direction by approximately one pitch of the valley of the male screw part. And having a state of being spiraled and straddling the thread of the male screw portion.

The fastening method of the present invention according to claim 9 is
A through hole provided in a central portion, a break from the outer periphery to the through hole, which prevents the retaining tool from surrounding the through hole and continuing over the entire circumference; and the through hole And a thread of a female thread of approximately one pitch for one pitch formed on the inner circumference of the male thread, and the thread of the female thread is screwed into a valley of the male thread portion provided on the outer circumference of the shaft portion of the male screw body. In this state, when the female screw and the male screw part are relatively pressed in the axial direction by a surface perpendicular to the axial direction of the female screw part, the screw thread of the female screw on one end side is removed from the valley of the male screw part. Overcoming the thread of the male thread part and entering a portion of the valley of the male thread part that is displaced in the axial direction by approximately one pitch, the thread of the female thread becomes non-spiral as a whole and the thread of the male thread part It is supposed to be in a state that straddles And the step of providing a stop missing,
Inserting the shaft portion of the male screw body into the fastened body;
The thread of the female screw of the retaining member is screwed into a valley of a male thread portion provided on the outer periphery of the shaft portion of the male threaded body, and the retaining member is pressed against the body to be fastened. The stopper is rotated relatively in the tightening direction, and the thread of the female screw on one end side of the retainer stops over the thread of the male thread from the valley of the male thread. Entering the portion shifted in the axial direction by approximately one pitch of the inner thread so that the thread of the female thread is non-spiral as a whole and straddles the thread of the male thread,
The method includes a step of screwing a nut into the male screw portion of the male screw body, and tightening the fastened body and the retaining member between the nut and the head of the male screw body.

The fastening method of the present invention according to claim 10 comprises:
A through hole provided in a central portion, a break from the outer periphery to the through hole, which prevents the retaining tool from surrounding the through hole and continuing over the entire circumference; and the through hole And a thread of a female thread of approximately one pitch for one pitch formed on the inner circumference of the male thread, and the thread of the female thread is screwed into a valley of the male thread portion provided on the outer circumference of the shaft portion of the male screw body. In this state, when the female screw and the male screw part are relatively pressed in the axial direction by a surface perpendicular to the axial direction of the female screw part, the screw thread of the female screw on one end side is removed from the valley of the male screw part. Overcoming the thread of the male thread part and entering a portion of the valley of the male thread part that is displaced in the axial direction by approximately one pitch, the thread of the female thread becomes non-spiral as a whole and the thread of the male thread part It is supposed to be in a state that straddles And the step of providing a stop missing,
Inserting the shaft portion of the male screw body into the fastened body;
The thread of the female screw of the retaining member is screwed into a valley of a male thread portion provided on the outer periphery of the shaft portion of the male threaded body, and the retaining member is pressed against the body to be fastened. The stopper is rotated relatively in the tightening direction, and the thread of the female screw on one end side of the retainer stops over the thread of the male thread from the valley of the male thread. Entering the portion shifted in the axial direction by approximately one pitch of the inner thread so that the thread of the female thread is non-spiral as a whole and straddles the thread of the male thread. It has.

The fastening structure according to claim 11 of the present invention is:
To-be-fastened body,
A male screw body having a shaft portion provided with a male screw portion on the outer periphery, and the shaft portion inserted through the fastened body;
A nut screwed into the male screw portion of the male screw body and tightening the fastened body between the head of the male screw body;
A through hole provided in a central portion, a break from the outer periphery to the through hole, which prevents the retaining tool from surrounding the through hole and continuing over the entire circumference; and the through hole A thread of a female thread of approximately one pitch for one pitch formed on the inner periphery of the thread, and after the thread of the female thread is screwed into the valley of the male thread portion of the male thread body, By rotating relatively in the tightening direction so as to be pressed against the end surface opposite to the body to be fastened, the thread of the female screw on one end side is threaded from the trough of the male screw part. And enters the portion of the valley of the male screw portion that is shifted in the axial direction by approximately one pitch, and the thread of the female screw becomes non-spiral as a whole and straddles the screw thread of the male screw part. Having a retaining device in a state A.

The fastening structure according to claim 12 of the present invention is:
To-be-fastened body,
A male screw body having a shaft portion provided with a male screw portion on the outer periphery, and the shaft portion inserted through the fastened body;
A through hole provided in a central portion, a break from the outer periphery to the through hole, which prevents the retaining tool from surrounding the through hole and continuing over the entire circumference; and the through hole A retainer having a thread of a female thread of approximately one pitch for approximately one pitch formed on the inner periphery of the screw, and a shaft portion of the male screw body inserted through the through hole;
A screw that is screwed into the male screw portion of the male screw body, and a nut that fastens the fastened body and the retaining member between the head of the male screw body,
The retainer is relatively pressed against one end surface of the nut or the fastened body from a state in which the thread of the female screw is screwed into the valley of the male screw portion of the male screw body. The thread of the female screw on the side of the male thread passes over the thread of the male screw part from the valley of the male screw part and enters a portion shifted in the axial direction by approximately one pitch in the valley of the male screw part. The mountain is non-spiral as a whole and is in a state of straddling the thread of the male screw part.

The fastening structure according to claim 13 of the present invention is:
To-be-fastened body,
A male screw body having a shaft portion provided with a male screw portion on the outer periphery, and the shaft portion inserted through the fastened body;
A through hole provided in a central portion, a break from the outer periphery to the through hole, which prevents the retaining tool from surrounding the through hole and continuing over the entire circumference; and the through hole And a thread of a female thread of approximately one pitch for one pitch formed on the inner periphery of the female thread, and after the thread of the female thread is screwed into the valley of the male thread portion of the male thread body, By being relatively rotated in the tightening direction so as to be pressed against the body, the thread of the female thread on one end side gets over the thread of the male thread part from the valley of the male thread part, and the valley of the male thread part A retaining device that enters a portion that is displaced in the axial direction by approximately one pitch, and that the thread of the internal thread is non-spiral as a whole and straddles the thread of the external thread; Is provided.

  In the present invention, when the retainer is first screwed into the male thread portion of the male thread body, the thread of the female thread of the retainer tool has a spiral shape, and the male thread body of the corresponding spiral thread has a spiral shape. Screwed into the valley of the male thread.

  Thus, in a state in which the thread of the female screw is screwed into the valley of the male screw portion of the male screw body, the retainer is relatively pressed in the axial direction against a surface perpendicular to the axial direction of the female screw and the male screw portion. Then, the thread of the female screw on the one end side of the retainer has moved over the thread of the male screw part from the valley of the male screw part and shifted in the axial direction by approximately one pitch of the valley of the male screw part. It enters into the portion, and the thread of the female thread is non-spiral as a whole and straddles the thread of the male thread.

  In such a state, the retainer is no longer a “female screw”, and cannot be rotated in the loosening direction with respect to the male screw body unless a large rotational force is applied using a tool. Therefore, the male screw body can be prevented from coming off from the fastened body.

  Then, when a large rotational force is applied to the retainer in the loosening direction using a tool, the thread of the female thread of the retainer that is non-spiral and straddles the thread of the male thread part However, since it returns to the state of being screwed again into the state of being screwed into the valley of the male threaded portion of the male threaded body, it can be rotated in the loosening direction. Therefore, when necessary, the fastening structure can be disassembled by releasing the retaining state.

  Further, as in the fastening method and the fastening structure according to claims 7 and 11, if the retainer is attached to the male screw body outside the nut, the thread of the female thread of the retainer is non-spiral as a whole as described above. This prevents the male screw body from coming off and at the same time prevents the nut from loosening. Further, the nut can be prevented from falling off.

  Further, as in the fastening method and the fastening structure according to claims 8, 9 and 12, if the retaining tool is interposed between the nut and the body to be fastened, the male screw body is prevented from coming off and at the same time the washer is attached to the retaining tool. The function as can be fulfilled.

  Further, as in the fastening method and the fastening structure according to claims 10 and 13, the retainer is relatively rotated in the tightening direction so that the retainer is pressed against the body to be fastened. The thread of the female thread on the one end side climbs over the thread of the male thread part from the valley of the male thread part and enters the portion shifted in the axial direction by approximately one pitch in the valley of the male thread part. As a non-spiral shape and straddling the thread of the male screw part, the fastened body can be fastened and the male screw body can be prevented from coming off from the fastened body without using a nut. can do.

The retaining tool, fastening method and fastening structure of the present invention are:
(A) The male screw body in the fastening structure can be prevented from coming off, and when necessary, the fastening structure can be disassembled by releasing the retaining state.
(B) The male screw body can be retained without special processing.
(C) If the retaining screw is attached to the male threaded body outside the nut, the male threaded body can be retained, and at the same time, the nut can be prevented from falling off and the nut can be prevented from loosening.
(D) If a retaining tool is interposed between the nut and the body to be fastened, the retaining screw can be made to function as a washer while retaining the male screw body.
(E) It is possible to fasten the fastened body without using a nut, and to prevent the male screw body from coming off from the fastened body.
It is possible to obtain excellent effects such as.

It is a perspective view which shows the retainer in Example 1 of this invention. It is a top view which shows the said stopper. It is a front view which shows the said retainer. It is a side view which shows the said stopper. It is sectional drawing in the VV line | wire of FIG. In Example 1, it is a front view which shows the state which screwed the retainer in the external thread body after clamping | tightening a nut. FIG. 7 is an enlarged longitudinal sectional view showing a screwed state of FIG. 6. In Example 1, it is a front view which shows the state which tightened the retaining tool and the one end part of the retaining tool began to contact the end surface of a nut. It is a principal part enlarged front view which shows the state of FIG. In Example 1, it is the front view which shows the state which tightened the retaining tool and changed the thread of the female screw of the retaining tool to the non-helical shape straddling the screw thread of the male screw part from the spiral shape until then. is there. It is a principal part enlarged front view which shows the state of FIG. It is a principal part expanded rear view which shows the state of FIG. 10 and 11 seeing from a back side. In Example 2 of this invention, after inserting an external thread body in a to-be-fastened body, it is a front view which shows the state which screwed the retaining tool to the external thread body. In Example 2, it is a front view which shows the state which screwed the nut in the external thread body, after rotating in a clamping | tightening direction until it came in contact with a to-be-fastened body. In Example 2, it is a front view which shows the state which rotated the nut in the clamp | tightening direction and the nut began to contact the retainer. In Example 2, it is a front view which shows the state which tightened the nut further and changed the screw thread of the internal thread of the retainer to the non-spiral form straddling the thread form of the external thread from the previous spiral form. . In Embodiment 3 of the present invention, the retainer is rotated in the tightening direction, the retainer is pressed against the body to be fastened, and the thread of the female thread of the retainer is changed from the previous spiral to the thread of the male thread. It is a front view which shows the state made to transfer to the non-spiral shape over a mountain. It is a front view which shows the fastening method and fastening structure in Example 4 of this invention. It is a top view which shows the retainer in Example 5 of this invention. It is a top view which shows the retainer in Example 6 of this invention. It is a top view which shows the retainer in Example 7 of this invention. It is a longitudinal cross-sectional view which shows the retainer in Example 8 of this invention.

  Hereinafter, the present invention will be described based on embodiments shown in the drawings.

  FIGS. 1-12 shows Example 1 of this invention, Among these, FIGS. 1-5 shows the retainer 1 in a present Example, FIGS. 6-12 has shown the clamping process in a present Example.

  Next, the retainer 1 in this embodiment will be described first with reference to FIGS. 1 to 5. The retainer 1 is formed by processing a metal plate such as stainless spring steel, stainless steel, spring steel, steel, As a whole, it has a flat shape, its outer periphery is a regular hexagonal shape with rounded corners, and a through hole 2 is provided in the center. And by providing the cut | interruption 3 from an outer periphery to the said through-hole 2, it is substantially C-shaped as a whole, and the said stopper 1 does not surround the through-hole 2 and continues over the perimeter. Has been.

  On the inner periphery of the through hole 2, a thread 4 of one female thread for approximately one pitch is formed. Compared with the thread 4 of this female screw and its vicinity, the other part of the retainer 1 is made thicker. Further, as well shown in FIGS. 5 and 7, the thread 4 of the internal thread is different from the thread form (triangular or trapezoidal) of the internal thread of the normal nut, and has a rectangular shape. In the free state, the retainer 1 is formed so that the thread 4 of the female screw has a spiral shape. As shown in FIG. 3, both ends 1a and 1b sandwiching the cut 3 are thereby formed. Is in a position shifted with respect to the axial direction (vertical direction in FIG. 3).

  The thread 4 of the female screw is preferably a complete spiral from the time when it is in a free state, but may not necessarily be a complete spiral when in a free state. As will be described later, when the male threaded portion 5 is screwed into a valley of the male threaded portion 7 provided on the outer periphery of the shaft portion 6 of the male threaded body 5 (see FIGS. 6 to 12), It is because it becomes a sufficient spiral according to the spiral.

  Next, the fastening method and fastening structure in a present Example are demonstrated using FIGS. First, as shown in FIG. 6, the shaft portion 6 of the male screw body 5 is inserted into the fastened bodies 8 and 9, the nut 10 is screwed into the male screw portion 7 of the male screw body 5, and the nut 10 is rotated in the tightening direction. The fastened bodies 8 and 9 are tightened between the nut 10 and the head 11 of the male screw body 5.

  Subsequently, the retainer 1 is screwed into the male screw portion 7 of the male screw body 5 as shown in FIG. FIG. 7 is an enlarged longitudinal sectional view showing a screwed state between the retaining tool 1 of FIG. 6 and the male threaded portion 7 of the male screw body 5, and the thread 4 of the female screw of the retaining tool 1 is spiral. And screwed into the valley of the male threaded portion 7 of the male threaded body 5.

  Next, when the retainer 1 is rotated in the tightening direction using a tool such as a finger or a spanner (not shown), the end of the retainer 1 in the tightening rotation direction first as shown in FIG. 1a contacts the end surface 10a of the nut 10 on the opposite side to the fastened bodies 8 and 9. FIG. 9 is an enlarged view of a main part of FIG.

  8 and 9, when the retainer 1 is further rotated in the tightening direction using a tool, the leading end 1a of the retainer 1 in the tightening rotation direction further moves toward the axial nut 10 side. For the reason explained below, the thread 4 of the internal thread on the leading end 1a side in the tightening rotation direction of the retainer 1 or the end 1b side on the tail end in the tightening rotation direction is Overcoming the thread 7a of the male thread 7 and entering a portion of the valley of the male thread 7 that is shifted in the axial direction by approximately one pitch, as shown in FIGS. It becomes a state where it is spiral and straddles the thread 7a of the male threaded portion 7. 11 is an enlarged view of the main part of FIG. 10, and FIG. 12 is an enlarged rear view of the main part showing the states of FIGS. 10 and 11 from the back side.

  According to the observation of the present inventor, as described above, when the thread 4 of the female thread becomes non-spiral as a whole and moves over the thread 7a of the male thread portion 7, (i) When the thread 4 of the internal thread on the end 1a side of the tightening rotation direction of the retainer 1 passes over the thread 7a of the external thread 7, (ii) the end 1b on the rear side in the tightening rotation direction on the opposite side It seems that there is a case where the thread 4 of the female thread on the side gets over the thread 7a of the male thread portion 7.

  Probably, the case of (i) seems to be overwhelmingly large, and the reason why the case of (i) occurs is considered as follows. When the stopper 1 is further rotated in the tightening direction from the state of FIGS. 8 and 9, and the end 1a on the leading side in the tightening rotation direction of the stopper 1 can no longer move to the axial nut 10 side, The thread 4 of the female thread on the end 1a side climbs the flank of the male thread part 7 while continuing to rotate, and climbs over the thread 7a of the male thread part 7 from the trough of the male thread part 7 and out of the trough of the male thread part 7 Of the screw thread 4 enters the portion shifted in the axial direction by approximately one pitch (the portion shifted upward in FIGS. 10 to 12), and the thread 4 of the female screw as a whole becomes non-spiral and straddles the thread 7 a of the male thread 7. It is thought that it will be in the state. A one-dot chain line 1 ′ in FIG. 11 shows a position when the thread 4 of the female screw 4 on the end 1a side in the tightening rotation direction of the retainer 1 remains spiral for reference.

  The probability of occurrence of the case (ii) seems to be small, but the reason for the occurrence of the case (ii) is considered as follows. Due to variations in processing accuracy of the retainer 1 at the time of manufacture, tilted engagement with the male screw body 5 and the like, the internal thread of the end portion 1a on the leading end 1a side in the tightening rotation direction of the retainer 1 It is considered that the end portion of the screw thread 4 is caught in the valley of the male screw portion 7 and cannot escape from the valley of the male screw portion 7. In such a case, the end of the thread 4 of the female screw on the end 1a side in the tightening rotation direction cannot advance further in the tightening rotation direction, so that the stopper 1 is rotated in the tightening direction. This acts to spread the retainer 1 so that the distance between both ends 1a and 1b is increased. As a result, a force that eliminates torsion caused by the helical shape forming of the retainer 1 acts simultaneously, and the thread 4 of the female thread on the end 1b side in the tightening rotation direction climbs the flank of the male thread 7. , Over the thread 7a of the male thread 7 from the valley of the male thread 7, and to a portion of the valley of the male thread 7 that is displaced in the axial direction by approximately one pitch (the portion displaced downward in FIGS. 10 to 12) It is considered that the screw thread 4 of the female screw enters the non-spiral shape as a whole and straddles the screw thread 7a of the male screw part 7. A one-dot chain line 1 ″ in FIG. 11 shows the position when the thread 4 of the female screw on the end 1b side on the tail side in the tightening rotation direction remains in a spiral shape for reference. It is thought that this may occur due to the operation mode of the tool.

  Regardless of which process is followed, if the thread 4 of the female thread is non-spiral as a whole and straddles the thread 7a of the male thread 7 as described above, the retainer 1 is no longer It is no longer a “female screw” and cannot rotate in the loose direction with respect to the male screw body 5 unless a large rotational force is applied using a tool. Therefore, the nut 10 is prevented from loosening, the nut 10 is prevented from falling off, and the male screw body 5 is prevented from coming off from the fastened bodies 8 and 9.

  Further, when a large rotational force is applied to the retainer 1 in the loosening direction using a tool, the retainer 1 that has become non-spiral and straddles the thread 7a of the male thread portion 7 can be obtained. Since the screw thread 4 of the female screw returns to the spiral shape and returns to the state of being screwed into the valley of the male screw part 7 of the male screw body 5, it can be rotated in the loosening direction. Therefore, when necessary, the fastening structure can be disassembled by releasing the retaining state.

  8-12, for convenience of drawing production, when the end portion 1a on the leading side in the tightening rotation direction of the retainer 1 starts to come into contact with the end surface of the nut 10, both end portions 1a, Both ends of the retainer 1 also come when the thread 1b comes to the front position and the thread 4 of the female thread becomes non-spiral as a whole and moves over the thread 7a of the male thread 7 However, of course, the both end portions 1a and 1b of the retainer 1 do not necessarily come to the front position at each time point. It is only for the convenience of drawing production.

  10-12, in the state where the thread 4 of the female thread of the retainer 1 is non-spiral as a whole and straddles the thread 7a of the male thread 7, the retainer 1 is completely Although it is depicted that it is in a single plane and is entirely seated on the nut 10, in reality, it is not necessarily always completely flat and seated on the nut 10. In some cases, it may be partially seated in a non-planar state. However, it is still possible to prevent the nut 10 from loosening, prevent the nut 10 from falling off, and prevent the male screw body 5 from coming off from the fastened bodies 8 and 9.

  Further, the retainer 1 of the present invention has a conventional generally ring shape as disclosed in Patent Documents 2 and 3, and has a female thread thread of approximately one pitch on the inner periphery. It should be noted that the preventive tool has a fundamentally different technical idea (in particular, the lock nut for preventing nut loosening disclosed in Patent Document 2 looks like this embodiment at first glance. Note that it is similar, but its essence is a completely different invention).

  In these conventional anti-loosening prevention devices, it is intended to prevent loosening by strongly pressing the flank of the female thread of the female screw of the anti-loosening device against the flank of the male screw portion of the male screw body. In the same way as a normal nut, the thread thread shape is a triangular thread shape that is the same as the thread thread shape of the male screw body, and the helical shape of the female thread thread in the free state is the spiral of the male thread part of the male screw body. When the screw thread of the female screw of the locking device is screwed into the valley of the male screw part of the male screw body, the flank of the female screw thread is stronger than the flank of the male screw part of the male screw body 5. It is trying to be suppressed. That is, in Patent Document 2, the height of the thread of the female screw increases as it approaches the other end from one end, and as shown in FIG. By pushing the vicinity of both ends of the intermediate product having the shape shown in the figure inward and plastically deforming it to obtain the final product, the female screw is shaped like a non-circular shape like an elliptical shape seen in the axial direction. I have to. Moreover, in patent document 3, the inclination of the helix of the female thread of the female screw of the locking prevention tool is made to differ greatly from the inclination of the helix of the male screw portion of the male screw body. In such a configuration, the thread of the female screw is always very strongly restrained by the valley of the male screw portion of the male screw body. Therefore, as in the present invention, the screw of the female screw on the one end 1a or 1b side of the stopper 1 is used. The thread 4 climbs over the thread 7a of the male thread 7 from the valley of the male thread 7 and enters a portion of the valley of the male thread 7 that is displaced in the axial direction by approximately one pitch, and the thread 4 of the female thread as a whole. There is absolutely no occurrence of a non-spiral phenomenon that shifts to a state over the thread 7a of the male threaded portion 7.

  In this embodiment, the thread 4 of the female thread 4 of the retainer 1 has a different shape from that of the male thread 7 of the male thread 5, and the thread 4 of the female thread is screwed into the valley of the male thread 7. In this state, since a larger gap is generated between the two than in the case of a normal nut screwing structure, the screw thread 4 of the female screw forms a spiral as a whole and is screwed into the valley of the male screw part 7. It is possible to shift from a state to a state in which it is non-spiral and straddles the thread 7 a of the male screw portion 7.

  In this embodiment, since the outer periphery of the retainer 1 has a hexagonal shape, the retainer 1 can be easily rotated using a tool such as a spanner. However, the outer periphery of the retainer 1 may have a non-circular shape other than a hexagon that is easy to rotate using a tool.

  13-16 has shown the fastening method and fastening structure in Example 2 of this invention. The retainer 1 is the same as that of the first embodiment.

  In this embodiment, first, after the shaft portion 6 of the male screw body 5 is inserted into the fastened bodies 8 and 9 as shown in FIG. 13, the retainer 1 is screwed into the shaft portion 6 of the male screw body 5.

  Next, as shown in FIG. 14, the retainer 1 is rotated in the tightening direction using a tool such as a finger or a spanner, and the end 1 a on the leading side in the tightening rotation direction of the retainer 1 is connected to the fastened body 8. Then, the nut 10 is screwed onto the shaft portion 6 of the male screw body 5.

  Next, when the nut 10 is rotated in the tightening direction, the seat surface 10b of the nut 10 presses the end 1b on the rear side in the tightening rotation direction of the retainer 1 as shown in FIG.

  Then, when the nut 10 is pressed in the axial direction by the bearing surface 10b, the thread 4 of the female thread on the end 1b side on the rear side in the tightening rotation direction causes the thread 7a of the male thread 7 to move from the valley of the male thread 7. The end 1a on the leading side in the tightening rotation direction is overcome by entering a portion of the valley of the male screw portion 7 that is shifted in the axial direction by about one pitch or by a reaction force received in the axial direction from the fastened bodies 8 and 9. The thread 4 of the female thread on the side climbs over the thread 7a of the male thread 7 from the trough of the male thread 7 and enters a portion of the trough of the male thread 7 that is displaced in the axial direction by approximately one pitch. Thus, the thread 4 of the female thread of the retainer 1 becomes non-spiral as a whole and shifts to a state straddling the thread 7 a of the male thread 7. Accordingly, as in the case of the first embodiment, the retainer 1 cannot be rotated in the loosening direction with respect to the male screw body 5 unless a large rotational force is applied using a tool. Therefore, even if the nut 10 is loosened and falls off the male screw body 5, the male screw body 5 can be prevented from coming off from the fastened bodies 8 and 9. Further, the retainer 1 can function as a washer.

  In the case of the above description, by tightening the nut 10 so that the retainer 1 is sandwiched between the nut 10 and the bodies 8 and 9 to be fastened, the retainer 1 is made of the female thread 4 as a whole. Although the non-spiral shape is shifted to the state of straddling the thread 7a of the male screw portion 7, before the nut 10 is screwed, the end 1a in the tightening rotation direction of the stopper 1 is Even after contacting the body 8 to be fastened, the retainer 1 is further rotated in the tightening direction, so that the retainer 1 becomes non-spiral as a whole in the thread 4 of the internal thread as in the case of the first embodiment. The same result can be obtained by shifting to a state over the thread 7a of the male screw portion 7, and then screwing the nut 10 into the male screw body 5 and tightening the nut 10 until it is seated on the retainer 1. .

  Further, as another method, the retaining member 1 and the nut 10 are sequentially screwed onto the shaft portion 6 of the male screw body 5, and the retaining member 1 is rotated together with the nut 10 in the tightening direction. The retaining screw 1 is shifted to a state where the thread 4 of the female screw is non-spiral as a whole and straddles the thread 7 a of the male screw part 7, and the nut 10 is fastened via the retaining tool 1. It is also possible to sit on the bodies 8 and 9.

  If all the parts of the retainer 1 have the same thickness, the thickness of all parts of the retainer 1 is constrained by the specifications such as the pitch of the male thread 7 of the male thread body 5 to be used, and the thickness can be freely set. Cannot be selected. However, in the retaining device 1 of the first embodiment used in this embodiment, the thickness of the other portion of the retaining device 1 is larger than the thread 4 of the female screw and the vicinity thereof. The thickness can be freely selected except for the mountain 4 and the vicinity thereof, and the thickness required in the case of functioning as a washer as in this embodiment can be set, and the strength of the stopper 1 can be increased.

  FIG. 17 shows a fastening method and a fastening structure in Embodiment 3 of the present invention. The retainer 1 is the same as that of the first embodiment.

  In this embodiment, the nut 10 is not used, and only the retainer 1 is attached to the male screw body 5. After the shaft portion 6 of the male screw body 5 is inserted into the fastened bodies 8 and 9, the retainer 1 is screwed into the shaft portion 6 of the male screw body 5, and the end portion 1 a on the leading side in the tightening rotation direction of the retainer 1. After the contact with the body 8 to be fastened, the retainer 1 is further rotated in the tightening direction. As in the case of the first embodiment, the retainer 1 has a female thread 4 as a whole in a non-spiral shape and is externally threaded. Transition to a state straddling the thread 7a of the part 7 is made.

  Thereby, although fastening force is smaller than the case where the nut 10 is used, the fastened bodies 8 and 9 can be fastened and the male screw body 5 can be prevented from coming off from the fastened bodies 8 and 9 without using the nut 10. .

  FIG. 18 shows a fastening method and a fastening structure in Embodiment 4 of the present invention. The retainer 1 is the same as that of the first embodiment.

  In the present embodiment, after one retaining device 1 is mounted on the male screw portion 6 of the male screw body 5 in the same manner as in the third embodiment, the retaining device 1 is formed so that the thread 4 of the female screw is non-helical as a whole. Then, after the transition is made so as to straddle the thread 7a of the male threaded portion 7, another retaining tool 1 is mounted on the male threaded part 6 of the male threaded body 5, and the retaining tool mounted first. 1, the thread 4 of the female screw is also non-spiral as a whole and is shifted so as to straddle the thread 7 a of the male thread 7. Thereby, compared with the case where only one retainer 1 is used as in Example 3, the fastening force can be increased. Note that the retainer 1 may be further used in a triple or more manner.

  FIG. 19 shows a retainer 1 according to Embodiment 5 of the present invention. In this embodiment, the thread 4 of the female thread is discontinuous with respect to the length direction (spiral direction) of the thread 4 and is respectively provided at both ends 1a, 1b of the retainer 1 and the inner periphery of the middle point. The provided projecting portions 4a, 4b, 4c projecting toward the center form a discontinuous female thread 4. Other configurations are the same as those in the first embodiment.

  In the retainer 1 of the first embodiment, the thread 4 of the female thread is continuous in the length direction of the thread 4, so that it is non-spiral as a whole and straddles the thread 7 a of the male thread 7. In this state, the part where the thread 4 of the female thread 4 is actually placed on the thread 7a of the male thread 7 is deformed into a state in which the retainer 1 is relatively widened. I was supposed to.

  However, in this embodiment, when the whole is non-spiral and straddles the thread 7a of the male thread 7, the female thread 4 does not exist on the thread 7a of the male thread 7. A portion (between the convex portions 4a and 4c or a portion between the convex portions 4b and 4c) can be provided so that the retainer 1 is not deformed into a widened state. Thereby, the retainer 1 is stably mounted by the shaft portion 6 of the male screw body 5, and the male screw body 5 from the fastened bodies 8 and 9 is prevented from coming off, the nut 10 is prevented from loosening, and the nut 10 is prevented from falling off. It can be done well.

  FIG. 20 shows a retainer 1 according to Embodiment 6 of the present invention. Also in this embodiment, the thread 4 of the female thread is discontinuous with respect to the length direction of the thread 4, but the convex portions 4a, 4b, 4d, 4e, 4f, 4g constituting the thread 4 of the female thread are provided. Is greater than that of the fifth embodiment. Other configurations are the same as those in the first embodiment.

  Also in this embodiment, the same effect as that of the sixth embodiment can be obtained.

  FIG. 21 shows a retainer 1 according to Embodiment 7 of the present invention. In this embodiment, the outer periphery of the retainer 1 is circular. Other configurations are the same as those in the fifth embodiment.

  By tightening the nut 10 so that the retainer 1 is sandwiched between the nut 10 and the fastened bodies 8 and 9 as described in the second embodiment, for example, the retainer 1 of the present embodiment is Even if a tool is used since the outer periphery is circular once the retaining device 1 is shifted to a state in which the thread 4 of the female thread as a whole is non-spiral and straddles the thread 7a of the male thread 7 It becomes extremely difficult to remove the stopper 1. Therefore, it is effective for applications such as tinkering.

  FIG. 22 shows the retainer 1 according to the eighth embodiment of the present invention. In the present embodiment, the retaining tool 1 as a whole has the same thickness.

  As described above, in such a configuration, the thickness of the retaining device 1 as a whole is constrained by the specifications such as the pitch of the male threaded portion 7 of the male threaded body 5 to be used, and the thickness is not freely selected. The manufacturing cost can be low.

  In each of the above-described embodiments, the thread 4 of the female thread of the retainer 1 has a rectangular shape, but in the present invention, one end 1a or 1b of the thread 4 of the female thread is used in a predetermined case. The side of the screw thread 7a of the male screw part 7 passes over the thread 7a of the male screw part 7 and enters the portion of the valley of the male screw part 7 that is shifted in the axial direction by approximately one pitch. The thread 4 of the female thread of the retainer 1 may be formed in another shape as long as the transition is made to the state over the thread 7 a of the male thread 7.

  Further, in the description of each of the above embodiments, the description has been given assuming that the retaining device rotates when the retaining device is attached to the male screw body. However, in some cases, the retaining device cannot be rotated. Needless to say, the male screw body may be rotated with respect to the retainer.

  In each of the above embodiments, the retainer 1 is made of metal, but in the present invention, the retainer may be made of a non-metallic material such as plastic or ceramic.

  As described above, the retaining tool, the fastening method, and the fastening structure according to the present invention are useful as a retaining tool, a fastening method, and a fastening structure for preventing the male screw body from coming out of the fastened body in the fastening structure.

DESCRIPTION OF SYMBOLS 1 Stopping tool 1a End part of tightening rotation direction of retaining tool 1b End part of tightening rotation direction of retaining tool 2 End side 2 Through hole 3 Cut 4 Thread of female thread 4a-4g Thread of discontinuous female screw 5 A male threaded body 6 Axial part 7 Male threaded part 7a Screw thread of male threaded part 8,9 Fastened body 10 Nut 10a End face of nut 10b Nut seating face 11 Head of male threaded body

Claims (13)

A retaining device attached to a male screw body having a shaft portion provided with a male screw portion on the outer periphery,
A through hole provided in a central portion, a break from the outer periphery to the through hole, which prevents the retaining tool from surrounding the through hole and continuing over the entire circumference; and the through hole And a thread of one female thread for approximately one pitch formed on the inner periphery of
In a state where the thread of the female screw is screwed into the valley of the male screw portion of the male screw body, when pressed relatively in the axial direction by a surface perpendicular to the axial direction of the female screw and the male screw portion, The thread of the female screw on one end side passes over the thread of the male screw part from the valley of the male screw part and enters a portion shifted in the axial direction by approximately one pitch of the valley of the male screw part, A retainer in which the thread is non-spiral as a whole and straddles the thread of the male thread.   The retainer according to claim 1, wherein a thread shape of the female screw has a shape different from that of the male thread portion of the male screw body.   The retainer according to claim 1 or 2, wherein the thread of the female screw is discontinuous in the length direction of the thread.   The retaining member according to any one of claims 1 to 3, wherein another portion is thicker than a thread of the female screw and the vicinity thereof.   The retainer according to any one of claims 1 to 4, wherein the outer periphery has a non-circular shape and can be rotated by fitting a tool to the outer periphery.   The retainer according to any one of claims 1 to 4, wherein the outer periphery has a circular shape. A through hole provided in a central portion, a break from the outer periphery to the through hole, which prevents the retaining tool from surrounding the through hole and continuing over the entire circumference; and the through hole And a thread of a female thread of approximately one pitch for one pitch formed on the inner circumference of the male thread, and the thread of the female thread is screwed into a valley of the male thread portion provided on the outer circumference of the shaft portion of the male screw body. In this state, when the female screw and the male screw part are relatively pressed in the axial direction by a surface perpendicular to the axial direction of the female screw part, the screw thread of the female screw on one end side is removed from the valley of the male screw part. Overcoming the thread of the male thread part and entering a portion of the valley of the male thread part that is displaced in the axial direction by approximately one pitch, the thread of the female thread becomes non-spiral as a whole and the thread of the male thread part It is supposed to be in a state that straddles And the step of providing a stop missing,
Inserting the shaft portion of the male screw body into the fastened body;
A step of screwing a nut into a male screw portion provided on an outer periphery of the shaft portion of the male screw body, and tightening the fastened body between the nut and the head of the male screw body;
The thread of the female screw of the retainer is screwed into the valley of the male thread portion of the male screw body, and the retainer is pressed against the end surface of the nut opposite to the body to be fastened. The retainer is rotated relative to the tightening direction, and the thread of the female screw on one end side of the retainer passes over the thread of the male thread from the trough of the male thread. Entering a portion shifted in the axial direction by approximately one pitch of the inner thread so that the thread of the female thread is non-spiral as a whole and straddles the thread of the male thread. A fastening method comprising: A through hole provided in a central portion, a break from the outer periphery to the through hole, which prevents the retaining tool from surrounding the through hole and continuing over the entire circumference; and the through hole And a thread of a female thread of approximately one pitch for one pitch formed on the inner circumference of the male thread, and the thread of the female thread is screwed into a valley of the male thread portion provided on the outer circumference of the shaft portion of the male screw body. In this state, when the female screw and the male screw part are relatively pressed in the axial direction by a surface perpendicular to the axial direction of the female screw part, the screw thread of the female screw on one end side is removed from the valley of the male screw part. Overcoming the thread of the male thread part and entering a portion of the valley of the male thread part that is displaced in the axial direction by approximately one pitch, the thread of the female thread becomes non-spiral as a whole and the thread of the male thread part It is supposed to be in a state that straddles And the step of providing a stop missing,
Inserting the shaft portion of the male screw body into the fastened body;
The thread of the female screw of the retaining device is screwed into the valley of the male screw portion provided on the outer periphery of the shaft portion of the male screw body, the retaining device is rotated relatively in the tightening direction, Bringing a stopper into contact with the fastened body;
A nut is screwed into the male screw portion of the male screw body, the fastened body and the stopper are tightened between the nut and the head of the male screw body, and the female screw on one end side of the stopper The thread of the male screw passes over the thread of the male screw part from the valley of the male screw part and enters a portion shifted in the axial direction by approximately one pitch of the valley of the male screw part. A fastening method including a step of forming a spiral shape across the thread of the male screw portion. A through hole provided in a central portion, a break from the outer periphery to the through hole, which prevents the retaining tool from surrounding the through hole and continuing over the entire circumference; and the through hole And a thread of a female thread of approximately one pitch for one pitch formed on the inner circumference of the male thread, and the thread of the female thread is screwed into a valley of the male thread portion provided on the outer circumference of the shaft portion of the male screw body. In this state, when the female screw and the male screw part are relatively pressed in the axial direction by a surface perpendicular to the axial direction of the female screw part, the screw thread of the female screw on one end side is removed from the valley of the male screw part. Overcoming the thread of the male thread part and entering a portion of the valley of the male thread part that is displaced in the axial direction by approximately one pitch, the thread of the female thread becomes non-spiral as a whole and the thread of the male thread part It is supposed to be in a state that straddles And the step of providing a stop missing,
Inserting the shaft portion of the male screw body into the fastened body;
The thread of the female screw of the retaining member is screwed into a valley of a male thread portion provided on the outer periphery of the shaft portion of the male threaded body, and the retaining member is pressed against the body to be fastened. The stopper is rotated relatively in the tightening direction, and the thread of the female screw on one end side of the retainer stops over the thread of the male thread from the valley of the male thread. Entering the portion shifted in the axial direction by approximately one pitch of the inner thread so that the thread of the female thread is non-spiral as a whole and straddles the thread of the male thread,
A fastening method comprising the steps of: screwing a nut into the male screw portion of the male screw body; and tightening the fastened body and the retaining member between the nut and the head of the male screw body. A through hole provided in a central portion, a break from the outer periphery to the through hole, which prevents the retaining tool from surrounding the through hole and continuing over the entire circumference; and the through hole And a thread of a female thread of approximately one pitch for one pitch formed on the inner circumference of the male thread, and the thread of the female thread is screwed into a valley of the male thread portion provided on the outer circumference of the shaft portion of the male screw body. In this state, when the female screw and the male screw part are relatively pressed in the axial direction by a surface perpendicular to the axial direction of the female screw part, the screw thread of the female screw on one end side is removed from the valley of the male screw part. Overcoming the thread of the male thread part and entering a portion of the valley of the male thread part that is displaced in the axial direction by approximately one pitch, the thread of the female thread becomes non-spiral as a whole and the thread of the male thread part It is supposed to be in a state that straddles And the step of providing a stop missing,
Inserting the shaft portion of the male screw body into the fastened body;
The thread of the female screw of the retaining member is screwed into a valley of a male thread portion provided on the outer periphery of the shaft portion of the male threaded body, and the retaining member is pressed against the body to be fastened. The stopper is rotated relatively in the tightening direction, and the thread of the female screw on one end side of the retainer stops over the thread of the male thread from the valley of the male thread. Entering the portion shifted in the axial direction by approximately one pitch of the inner thread so that the thread of the female thread is non-spiral as a whole and straddles the thread of the male thread. The fastening method which has. To-be-fastened body,
A male screw body having a shaft portion provided with a male screw portion on the outer periphery, and the shaft portion inserted through the fastened body;
A nut screwed into the male screw portion of the male screw body and tightening the fastened body between the head of the male screw body;
A through hole provided in a central portion, a break from the outer periphery to the through hole, which prevents the retaining tool from surrounding the through hole and continuing over the entire circumference; and the through hole A thread of a female thread of approximately one pitch for one pitch formed on the inner periphery of the thread, and after the thread of the female thread is screwed into the valley of the male thread portion of the male thread body, By rotating relatively in the tightening direction so as to be pressed against the end surface opposite to the body to be fastened, the thread of the female screw on one end side is threaded from the trough of the male screw part. And enters the portion of the valley of the male screw portion that is shifted in the axial direction by approximately one pitch, and the thread of the female screw becomes non-spiral as a whole and straddles the screw thread of the male screw part. Fastening with a retaining device in a state Elephants. To-be-fastened body,
A male screw body having a shaft portion provided with a male screw portion on the outer periphery, and the shaft portion inserted through the fastened body;
A through hole provided in a central portion, a break from the outer periphery to the through hole, which prevents the retaining tool from surrounding the through hole and continuing over the entire circumference; and the through hole A retainer having a thread of a female thread of approximately one pitch for approximately one pitch formed on the inner periphery of the screw, and a shaft portion of the male screw body inserted through the through hole;
A screw that is screwed into the male screw portion of the male screw body, and a nut that fastens the fastened body and the retaining member between the head of the male screw body,
The retainer is relatively pressed against one end surface of the nut or the fastened body from a state in which the thread of the female screw is screwed into the valley of the male screw portion of the male screw body. The thread of the female screw on the side of the male thread passes over the thread of the male screw part from the valley of the male screw part and enters a portion shifted in the axial direction by approximately one pitch in the valley of the male screw part. A fastening structure in which the mountain is non-spiral as a whole and straddles the thread of the male screw part. To-be-fastened body,
A male screw body having a shaft portion provided with a male screw portion on the outer periphery, and the shaft portion inserted through the fastened body;
A through hole provided in a central portion, a break from the outer periphery to the through hole, which prevents the retaining tool from surrounding the through hole and continuing over the entire circumference; and the through hole And a thread of a female thread of approximately one pitch for one pitch formed on the inner periphery of the female thread, and after the thread of the female thread is screwed into the valley of the male thread portion of the male thread body, By being relatively rotated in the tightening direction so as to be pressed against the body, the thread of the female thread on one end side gets over the thread of the male thread part from the valley of the male thread part, and the valley of the male thread part A retaining device that enters a portion that is displaced in the axial direction by approximately one pitch, and that the thread of the internal thread is non-spiral as a whole and straddles the thread of the external thread; A fastening structure comprising:

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