JPH1162939A - Female screw member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly remove a peeled coating film, to prevent entrance of the removed coating film to a space between a nut seat surface and a mating contact surface, to provide an excellent fastening force, and to prevent the occurrence of the increase of fastening excessiveness and seizure, in a nut having a function to peel a coating film adhered to a male screw member. SOLUTION: Independently from the main female screw part 7 of a nut 1, the proper number of protrusion parts 9 form removing a foreign substance are formed on the seat surface 2 side, and a preceding end face in a threadely engaging direction forms a paint peel surface 10. A plurality of the protrusion parts 9 for removing a foreign substance are formed in a plurality of spots and a coating film gathering part 11 is formed between the protrusions 9 for removing a foreign substance. The coating film gathering part 11 is formed in a spot deep by length longer than the prepared hole diameter 12 of the main female screw part 7, and achieves a role to contains coating film refuse peeled by the coating film surface 10. This constitution prevents entrance of the coating film to a space between a seat surface 2 and a mating contact surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a female screw member such as a nut, and more particularly, has a function of peeling off or removing a foreign substance such as a paint film or dust and a function of preventing loosening when screwed with a male screw member. It relates to a female screw member.

[0002]

2. Description of the Related Art Heretofore, in order to tighten a bolt having a coating film or the like attached thereto with a female screw member such as a nut, the bolt has been slightly forcibly tightened due to an increase in the diameter of the bolt due to the thickness of the coating film or the like.
Also, the nut described in Japanese Utility Model Publication No. 5-39211,
At the time of screwing with the counterpart, the end in the direction of travel of the projection formed further ahead of the tip in the screwing direction is raised substantially perpendicularly to the inner peripheral surface of the screw. According to such a nut, at the time of screwing with the other party, the vertical surface of the convex portion located at the head according to the progress of the screwing, for example, peels off the coating film attached to the screw thread of the bolt, Can be discharged as the screwing proceeds.

[0003]

When a bolt having a paint film or the like adhered thereto is tightened with a normal nut, foreign matter such as a paint film generated during the tightening enters between the thread of the nut and the thread of the bolt. In some cases, the movement of the nut is hindered by the foreign matter, and the thickness and viscosity of the coating film may cause tightening resistance. Further, according to the nut of the above-mentioned publication, although the problem that foreign matter enters between the thread of the nut and the thread of the bolt can be eliminated or suppressed, the coating film or the like peeled off by the convex portion is not on the seat surface side of the nut. Because the extruded coating film and the like may enter between the nut seat surface and the abutting surface of the mating member when the nut is fastened, the undesired effect on the nut fastening force may occur. Conceivable.

[0004] On the other hand, there is another problem as follows. That is, in the nut, since the convex portion for peeling off the paint film is formed prior to the female screw portion, the nut seat surface side in the state of being screwed and fastened to the male screw portion has a screw hole inner periphery. A gap (a non-screw engaging portion where the male screw portion and the female screw portion do not mesh with each other) corresponding to the height of the convex portion is formed between the surface and the outer peripheral surface of the male screw portion. As a result, the screw fastening force is reduced as compared with a nut of the same size in which a female screw portion is formed over the entire length, and loosening is likely to occur in the screw fastening state. There was a situation that the axial dimension had to be necessarily increased.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a function of removing foreign matter such as a coating film attached to a male screw member such as a bolt to be screwed, and that foreign matter such as a peeled coating film can be removed from its own seating surface by a male screw. It is possible to prevent or suppress entry between the contact surface of the member and the member, thereby easily tightening the male screw member to which foreign matter is attached, and also to the problem of screw loosening caused by the addition of the foreign matter removing function. It is an object of the present invention to provide a female screw member which can be satisfactorily avoided without increasing the size.

[0006]

Means for Solving the Problems and Functions / Effects In order to solve such problems, the first configuration of the female screw member of the present invention has the following features. That is, the female screw member has a female screw portion, the male screw portion of the male screw member is screwed to the female screw portion, and the screwing direction of the female screw portion is set to remove foreign matter such as a coating film attached to the male screw portion. In the foreign matter removing portion formed at the leading end of the female screw portion, the foreign matter removing portion for removing the foreign matter formed on the foreign matter removing convex portion screwed with the male screw portion adjacent to the leading end side of the female screw portion Having. Then, the foreign matter adhering to the male screw portion is removed by the foreign matter removing portion, and a foreign matter accumulation portion for accommodating the removed foreign matter is formed in a region on the inner peripheral surface of the self-threaded portion on the leading side in the screwing direction from the female screw portion. I do. In addition, at least a part of the outlet side end of the inlet side end and the outlet side end of the screwing of the female screw portion to the male screw member is arranged so that the internal diameter of the female screw there is smaller than the intermediate portion. By reducing the diameter in the section, a reduced-diameter female screw portion for preventing loosening is formed.

With the above-described structure, the foreign matter removed by the foreign matter removing section is accommodated in the foreign matter accumulation section, and foreign matter enters between the seating surface of the female screw member such as a nut and the contact surface of the mating member. This can enhance the nut fastening force. In addition, even if the female screw portion dimension of the female screw member is shortened due to the formation of the foreign matter removing portion and the screw fastening force is reduced, since the reduced diameter female screw portion for preventing loosening is formed, the axial dimension of the female screw member is reduced. The loosening of the screw fastening state can be avoided without increasing the size, so that the material yield can be improved and the weight of the female screw member can be avoided.

The female screw member to which the present invention is applied is typically a nut screwed into a male screw member such as a bolt, but a weld nut fixed to another member,
The present invention can also be applied to a member that does not take the form of a nut, for example, a female screw portion formed on a mold or a frame.

The foreign matter removing portion can be formed in a foreign matter removing convex portion provided in a region further preceding the leading end of the female screw portion in the screwing direction, and the removing convex portions are arranged at predetermined intervals. A plurality can be provided. In addition, the foreign material reservoir can be formed as a first concave portion deeper than a threaded hole diameter of the female screw portion on the inner peripheral surface between the foreign material removing convex portions in the preceding region. As a result, the peeled coating film or the like is stored in the first recessed portion, and continues to be stored in the foreign matter accumulation portion even after the completion of the screwing. On the other hand, when the first recessed portion is opened on the seating surface of the female screw member, a considerable gap is generated between the inner peripheral surface of the female screw portion and the outer peripheral surface of the male screw portion, and the screw fastening is performed. The contribution of the frictional force for maintaining the state from the bearing surface is reduced. However, since the above-mentioned reduced diameter female screw portion for preventing loosening is formed, it is possible to maintain a good screw fastening state even in this case.

[0010] A non-thread forming portion having a fixed width is provided on the inner peripheral surface on the leading side in the screwing direction of the female screw portion, and the non-thread forming portion is provided with a cylindrical guide portion at the start of screwing with the male screw portion. At the same time, the non-thread forming portion can be used as a foreign matter accumulation portion. In this case, the non-screw forming portion is also used as the foreign-matter accumulating portion and the guide portion at the time of screwing, and advantageously fulfills these two roles.

The above-mentioned non-thread forming portion is further formed with a concave portion (hereinafter referred to as a second concave portion) which is deeper than the diameter of the screw hole of the female screw portion. It can also be a reservoir. In this case the second
A plurality of recesses may be formed intermittently in the circumferential direction, or may be formed in a continuous annular shape.

Further, the second concave portion is formed to have a width reaching, for example, the seat surface of the nut.
The concave portion can be formed so as to open to the seat surface side of the nut, and does not reach the seat surface of the nut or the like, and a cylindrical guide portion of a fixed width serving as a guide when screwing into the seat surface side. Can also be left. In any case, when the second concave portion is a foreign matter accumulation portion deeper than the screw hole diameter, a considerable portion of the foreign matter can be accommodated therein, and therefore, the non-thread forming portion (in other words, the non-thread forming portion functioning as the foreign matter accumulation portion) And guide)
Can be made shorter, for example, the axial dimension of the nut can be reduced, and dimensional restrictions are relaxed.

A first recess is formed between a plurality of foreign matter removing projections having a foreign matter removing portion, and the above-described non-thread forming portion (guide portion) is formed in a region on the leading side in the screwing direction. May be formed to form a second recess therein, that is, the first recess and the second recess may be provided at the same time. In that case, the depth of the first recess and the second recess may be the same or different. And thus the first
In the case where the concave portion and the second concave portion are provided at the same time, even if the peeled coating film residue or the like is considerably large, it can be dispersed and accommodated in the first concave portion and the second concave portion. For example, if the capacity of the first recess is full, the second recess can accommodate the overflow.

Next, the female screw member according to the second configuration of the present invention has the following features. That is, the female screw member is
It has a female screw part, and the male screw part of the male screw member is screwed to the female screw part, and formed at the leading end of the female screw part in the screwing direction to remove foreign substances such as paint film attached to the male screw part And a foreign matter removing portion for removing foreign matter formed on a convex portion which is located on the leading end side of the female screw portion and which is screwed with the male screw portion in the screwing.
In the section from the leading end of the female screw portion or the convex portion where the spiral foreign matter removing portion is formed to a predetermined position on the spiral, a female screw is provided along at least a part of the section. In a plane orthogonal to the central axis of the part, a relief portion is formed in which the distance from the central axis to its inner edge is greater than the distance from the central axis to the inner edge of the foreign matter removing portion. Further, similarly to the female screw member of the first configuration, the outlet-side end portion of the inlet-side end portion and the outlet-side end portion of the screwing of the female screw portion to the male screw member has a female screw inner diameter larger than that of the intermediate portion. The diameter is reduced in at least a part of the section in the circumferential direction so as to reduce the size, thereby forming a reduced-diameter female screw portion for preventing loosening.

According to the female screw member having the above-described structure, even if a foreign substance such as a coating film adheres to a male screw portion such as a bolt to be screwed, it can be tightened while removing the foreign substance. Further, since the escape portion is formed following the foreign matter removal portion, the foreign matter such as the removed coating film is smoothly discharged through the escape portion, so that the thread on the female screw member side and the male screw member side are removed. Foreign matter hardly occurs between the screw and the thread. Furthermore, in the formation region of the escape portion, for example, the contact area or contact pressure between the thread of the external thread member covered with foreign matter such as a coating film and the like is reduced, so that the frictional resistance at the time of screwing can be reduced. it can. As described above, even if foreign matter such as a coating film adheres to the male screw portion, smooth screwing and tightening can be performed. In addition, even if the female screw portion dimension of the female screw member is shortened due to the formation of the foreign matter removing portion and the screw fastening force is reduced, since the reduced diameter female screw portion for preventing loosening is formed, the axial dimension of the female screw member is reduced. The loosening of the screw fastening state can be avoided without increasing the size, so that the material yield can be improved and the weight of the female screw member can be avoided.

In the above-mentioned relief, the distance from the central axis to the inner edge of the spiral is set along the spiral of the female screw portion or the projection for removing foreign matter in a plane perpendicular to the central axis of the spiral. It can be formed so that it becomes larger continuously or stepwise as the distance from the end increases. For example, when the foreign matter removing portion is formed by the foreign matter removing convex portion, the escape portion extends from the leading end of the spiral of the foreign matter removing convex portion toward the terminal end thereof, from the center axis to the inner edge of itself. The distance can be formed so as to increase continuously. By forming the escape portion in this manner, an edge or a blade portion suitable for removing foreign matter can be formed at the leading end of the spiral as the foreign matter removing portion, and the coating film or the like attached to the male screw portion can be smoothly peeled off. can do. In this case, at the leading end of the spiral, the angle formed between the front end surface of the projection for removing foreign matter and the inner peripheral surface of the relief portion (if the inner peripheral surface is a curved surface, its tangent plane at the leading end of the spiral) is an acute angle. By forming the clearance, the cutting effect of the foreign matter removing portion on foreign matter can be enhanced, and the foreign matter removing effect can be further enhanced. In the case where the female screw member of the present invention is manufactured by, for example, a cold forging method, the foreign matter removing portion and the edge of the thread segment or the tip of the blade portion described later may be slightly within a range in which a necessary and sufficient foreign matter removing effect can be achieved. It may be rounded.

In the female screw member having the second configuration, a foreign matter reservoir similar to the female screw member having the first configuration can be formed.

Next, the female screw member of the third configuration of the present invention has the following features. That is, the female screw member has a main female screw portion, and the main female screw portion is provided on the male screw portion of the male screw member so as to be located on the leading end side in the screwing direction with the male screw member to be screwed with the main female screw portion. A foreign matter removing female screw portion for removing foreign matter such as an adhered coating film is formed, and the female thread of the foreign matter removing female screw portion extends from a leading end of the spiral to a predetermined position in a section from the leading end of the spiral to the predetermined position. The inner diameter is formed to increase continuously or stepwise toward the leading end of the portion. Further, similarly to the female screw members of the first and second configurations, the female screw inside diameter of the female screw inner diameter at the outlet side end of the female screw part with respect to the male screw member is determined. The diameter is reduced in at least a part of the circumferential direction so as to be smaller than the intermediate portion, thereby forming a reduced-diameter female screw portion for preventing loosening.

According to the above configuration, the internal thread of the foreign matter removing internal thread portion is formed such that the inner diameter increases continuously or stepwise toward the leading end thereof. It can be tightened while being cut in a stepwise manner, the resistance due to the thickness and viscosity of the coating film or the like is reduced, and smooth tightening can be performed. In addition, even if the female screw portion dimension of the female screw member is shortened due to the formation of the foreign matter removing portion and the screw fastening force is reduced, since the reduced diameter female screw portion for preventing loosening is formed, the axial dimension of the female screw member is reduced. The loosening of the screw fastening state can be avoided without increasing the size, so that the material yield can be improved and the weight of the female screw member can be avoided.

The above-mentioned foreign matter removing female screw portion is provided with a foreign matter collecting portion for accommodating foreign matter such as a paint film removed by the foreign matter removing female screw portion by notching it radially at an intermediate portion in the circumferential direction. It can be formed in a concave shape. As a result, the foreign matter removed by the foreign matter removing
The nut is accommodated in the foreign matter accumulation portion, and for example, it is possible to prevent or suppress foreign matter from entering between the nut seating surface and the contact surface of the mating member, thereby enhancing the nut fastening force. In addition, by forming the foreign material pool portion deeper than the root diameter of the foreign material removing female screw portion, the peeled coating film and the like continue to be stored in the foreign material pool portion even after completion of screwing, so that when removing and attaching the screw thereafter. In addition, clogging of the screw thread due to the removed foreign matter hardly occurs.

[0021] A plurality of the above-mentioned foreign substance accumulation portions can be formed at predetermined intervals in the circumferential direction. In this way, foreign matter such as a coating film can be dispersed and accommodated in each foreign matter accumulation part, so that the foreign matter is more efficiently removed from the thread,
As a result, the screws can be tightened more smoothly. In addition, by forming a plurality of foreign matter accumulation portions in this way, the foreign matter removing female screw portion is divided into a plurality of thread segments arranged in the screwing direction. As a result, an edge (or a blade portion) suitable for removing foreign matter is formed at the leading edge of the threaded segment of the divided thread segment on the leading side of the thread engagement, and foreign matter can be removed more smoothly and reliably. In this case, the female thread of the foreign matter removing female thread is formed so that the height gradually decreases in units of one or more thread segments as it approaches the leading end side in the screwing direction with the male thread. Can be.

According to this configuration, when focusing on a specific external thread, the foreign matter such as the coating film is gradually removed step by step every time one or a plurality of thread segments pass. Can be performed more smoothly and reliably. For example, when removing the coating film adhered to the bolt, about half of the total thickness of the coating film in the first thread segment on the leading end side in the screwing direction is reduced to the coating remaining in the next second thread segment. Removal of the coating proceeds in such a manner that about half of the coating is further removed, and all of the coating remaining on the third thread segment is further removed, so that smoother tightening can be achieved. Further, since the height of the female thread of each thread segment can be made substantially constant, the height can be easily controlled at the time of forming the female thread, and the production efficiency of the female screw member can be improved.

In addition, as a more specific configuration of the above-mentioned foreign substance accumulating portion, the same one as the above-described female screw member of the first configuration can be applied to the third configuration.

Next, the diameter-reduced female screw portion can be formed by reducing the diameter of the outlet end of the female screw portion over the entire circumference so that the internal diameter of the female screw is smaller than that of the intermediate portion. . In addition, the thread of the reduced diameter female screw portion is formed as a concave / convex portion which is continuously repeated in the circumferential direction, and the convex portion (hereinafter, referred to as a loosening prevention convex portion) projects toward the center side of the reduced diameter female screw portion, and the concave portion of the reduced diameter female screw portion is formed. Formed in a form that recedes from the center side, and
The diameter of the inscribed circle that connects the tip of the convex part
In the state where the male screw member is screwed to the female screw portion and the male screw member is screwed to the female screw portion, a plurality of locking protrusions of the unevenness in the threads of the reduced diameter female screw portion are formed by the male screw member. It is possible to adopt a configuration in which the male screw member is tightened from the outer periphery in a state where the root of the member is pressed and elastically compressed by the reaction.

According to the above structure, the diameter of the female screw at the outlet end is reduced in a tapered shape over the entire circumference so as to be smaller than that of the intermediate portion to form a female screw having a conical cross section.
Variations in the deformation of the female screw portion unlike the case where a part of the entire circumference is deformed by applying a pressing force are less likely to occur. Moreover,
The thread of the reduced-diameter female thread is formed with irregularities that are repeated continuously in the circumferential direction, and the threads of the male thread member are uniformly contacted by the convexities of the irregularities over the entire circumference. Friction is smaller than in the case of pressing all over the mountain, and seizure is less likely to occur. In addition, even if the female screw portion dimension of the female screw member is shortened due to the formation of the foreign matter removing portion and the screw fastening force is reduced, since the reduced diameter female screw portion for preventing loosening is formed, the axial dimension of the female screw member is reduced. The loosening of the screw fastening state can be avoided without increasing the size, so that the material yield can be improved and the weight of the female screw member can be avoided. Further, since the tightening force is applied uniformly over substantially the entire circumference by the loosening prevention convex portion of the continuously repeated unevenness, the loosening prevention effect is large.

[0026] Here, when the thread locking prevention protrusions of the reduced-diameter female screw portion exert a pressing force between the root of the male screw member and the thread side surface, the screw locking prevention protrusions are elastic. Is compressed, but at this time, since there are concave portions on both sides of the loosening prevention convex portion, the compressed meat portion of the loosening prevention convex portion easily escapes to both sides (in other words, the compressive force is easily distributed to the concave portions on both sides), This suppresses a drastic increase in torque at the time of screwing, and a good locking function is achieved in a press-contact state between the plurality of locking protrusions and the roots or the thread side surfaces after screwing is completed. In other words, both reduction of the torque at the time of screwing and enhancement of the loosening prevention function are realized.

The specific shape of the concavities and convexities of the reduced-diameter female screw portion is, for example, a wavy shape in an arc shape, a triangular or trapezoidal shape in which the anti-loosening convex portion becomes wider from the distal end side to the proximal end side in plan view, and the concave portion is An inverted triangular shape or an inverted trapezoidal shape may be used. Regardless of the shape, the tip of the locking stopper has a smaller cross-sectional area than its base, so it is easily elastically deformed,
Therefore, the tightening torque can be reduced. In the case of an arc-shaped waving form, the contact area between the convex portion and the threaded portion of the male screw member is reduced, the seizure prevention effect is increased, and the life of the mold is improved. On the other hand, a trapezoidal shape can increase the locking effect.

Preferably, the unevenness of the thread of the reduced-diameter female screw portion is formed continuously over a plurality of threads, and between the adjacent threads, a concave portion of the unevenness and a convex portion for preventing loosening are formed. Each is formed at a corresponding position on a substantially tapered straight line traversing the threads. This makes it easy to process the unevenness.

More specifically, it is preferable that the number of the threads having the unevenness is desirably set to 2 or more and 4 or less, and the number of the convex portions is set to be in a range of 6 to 20. This range is suitable for maintaining the balance between the above-described effect of preventing seizure and reducing the tightening torque and the effect of preventing loosening.

Next, the method for manufacturing the female screw portion and the reduced diameter female screw portion of the female screw member according to the present invention is a method for manufacturing the female screw portion material by using the end portion of the female screw member material which is to be the outlet end of the screw engagement with the mating male screw member. The step of forming a female screw hole for the outlet side end having irregularities that are continuously repeated in the circumferential direction on the inner periphery, and before or after or simultaneously with the step, concentrically with the female screw hole for the outlet side end A step of forming a main female screw hole continuous in the axial direction, and the outlet side end female screw hole and the main female screw hole, and unevenness of the outlet side end remains, formed at the outlet side end A step of cutting the internal thread so that the thread of the internal thread is continuously repeated in the circumferential direction, and tapering the outlet side end over the entire circumference so that the internal diameter of the internal thread is smaller than the middle part. Diameter female thread with conical cross section Forming and comprising a.

As another method, a step of forming a female screw pilot hole that penetrates the female screw material in the axial direction, and the female screw material should be an outlet end of a screw engagement with a counterpart male screw member. Forming a continuous unevenness in the circumferential direction so as to go around the inner peripheral surface of the internal thread hole at the side end, and a female screw hole at the outlet side end where the unevenness is formed and the other. A step of cutting the female screw so that the unevenness at the outlet end thereof remains over the female screw pilot hole where the unevenness is not formed, and the screw thread of the female screw is continuously repeated in the circumferential direction, and the outlet side end And forming a tapered female screw portion having a conical cross section by tapering the entire circumference so that the internal diameter of the female screw is smaller than that of the intermediate portion.

In any case, according to these methods,
Continuous unevenness is formed in one or a plurality of threads on the thread at the outlet end of the female screw portion, and a desired reduced diameter form can be easily obtained. In addition, the diameter-reduced female screw portion is formed at the outlet side end so that the diameter of an inscribed circle connecting the protruding tips of the concave and convex portions of the female screw thread is smaller than the root diameter of the male screw member to be screwed there. The manufacturing method may be formed.

Further, the diameter reducing step of forming the diameter reducing screw portion includes:
Specifically, the outer peripheral surface of the outlet side end portion of the female screw portion material is a tapered outer peripheral surface having an outer diameter smaller as the end edge thereof, and a die having a tapered inner peripheral surface engaged with the tapered outer peripheral surface is formed by a female screw. The pressing can be performed by a method of pressing the tapered outer peripheral surface of the component material in the axial direction relatively. As described above, the outer peripheral surface of the outlet end of the female screw member is tapered, so that the distal end portion becomes thinner, and the female screw portion of the outlet end has a concave portion that repeats continuously over the entire circumference. Inward drawing can be easily performed, and the outlet end can be uniformly reduced in diameter.

[0034]

Embodiments of the present invention will be described below with reference to some embodiments shown in the drawings. (Embodiment 1) FIG. 1 shows a nut 1 having a coating film peeling function or a dust removing function and a loosening preventing function as one embodiment according to the first configuration of the female screw member of the present invention. FIG. 2 is a view from the seat surface 2 side. The nut 1 has a hexagonal portion 3 formed at an intermediate portion thereof, a flat flange portion 4 formed at an inlet side of a bolt to be screwed, and an outlet side end portion 5 at which the tip of the bolt is located or protrudes. It has an integral structure. It also has the appearance of a frustoconical frustoconical shape (FIGS. 1 and 2), which is the tapered outer peripheral surface 6, and the end surface of the flange 4 (the end on the inlet side) is the seating surface 2. However, the flange portion 4 is not essential, and the end surface of the hexagonal portion 3 may be the seating surface 2.

In the cylindrical space passing through the flange 4 from the outlet end 5, the main female screw 7
The outlet end 5 is formed with a reduced diameter female thread 8 concentric with the main female thread 7 and reduced in diameter. One or more foreign matter removing projections 9 are formed on the inner peripheral surface of the cylinder closer to the seating surface 2 than the main female screw portion 7. The end surface on the advancing side in the screwing direction of the foreign matter removing projection 9 serves as a foreign matter removing portion (in this example, the coating film peeling surface 10) which rises almost perpendicularly from the inner peripheral surface of the cylinder. The foreign matter removing projections 9 may be provided at three positions in the circumferential direction at equal angular intervals and three (three) in the axial direction as in this example, or may be provided as two or one. Is also good.

As shown in FIGS. 2 and 3, three concave portions 11 are formed between the foreign material removing convex portions 9 formed at the three circumferential positions as described above, for example, at 120 °. They are formed at equal angular intervals, and serve as foreign material accumulation portions (in this example, coating film accumulation portions). Hereinafter, the concave portion 11 is also referred to as a coating film pool portion (or a first coating film pool portion). Although this portion mainly stores the coating film peeled off on the coating film peeling surface 10, it goes without saying that foreign matter such as dust can also be stored together. As shown in FIG. 1 (b), the coating film reservoir 11 (recess) is formed to be deeper by a certain amount than the diameter of the prepared hole 12 of the main female screw portion 7, and this reaches the seating surface 2 and is formed on the surface. It is open. In addition, as shown in FIG. 4, the coating film reservoir 11 may be formed in a closed form so as not to reach the seating surface 2.

As shown in FIG. 5, when the male screw portion 14 of the male screw member 13 such as a bolt and the nut 1 are screwed, the foreign matter removing convex portion 9 is provided prior to the main female screw portion 7.
Is screwed into the male screw portion 14 of the male screw member 13, and the coating film peeling surface 10 of the foreign matter removing projection 9 peels off the coating film or the like adhered to the male screw portion 14, and stores it in the coating film pool portion 11. .
FIG. 6 shows that when the nut 1 is screwed into the male screw member 13, the coating film P attached to the male screw portion 14 of the male screw member 13 is peeled off, and the peeled coating film P ′ is attached to the seating surface 2 of the nut 1. 2 shows a state where the film is accommodated in the coating film pool 11 on the side. Reference numeral 15 denotes a contact surface of the other party.

As in the nut 16 shown in FIG. 7, the hexagonal portion 3 and the flange portion 4 have a continuous and slightly long dimension in the axial direction. A larger (deep) cylindrical guide portion 17 may be formed so as to constitute a part or all of the coating film pool portion. Here, the circumferential region between the above-described foreign matter removing projections 9 is a recessed portion (coating film accumulation portion) 11 similar to that described above. If the peripheral surface between the foreign matter removing projections 9 is formed, for example, as a part of a cylindrical surface coinciding with the screw hole 12, this part has a low function as a coating film accumulation part, and the cylindrical guide part is formed. 17 substantially functions as a coating film pool. The cylindrical guide portion 17 also serves as a guide portion for guiding the male screw member when it is screwed.

On the other hand, like the nut 18 shown in FIG. 8, a second concave portion 19 is further formed on the cylindrical guide portion 17 of FIG. 7, and this concave portion 19 is formed by the cylindrical guide portion 17 and the first concave portion.
It may be configured so as to function as a coating film reservoir together with the recessed portion 11 of FIG. The second concave portion 19 can be formed in a circumferentially annular groove shape so as not to reach the seat surface 2. However, as shown in FIG. 9, three concave portions 19 may be formed intermittently in the circumferential direction, for example, at equal angular intervals of 120 °.

Returning to FIG. 1, the reduced diameter female screw portion 8 is uniformly reduced in diameter over its entire circumference so that the inner diameter of the female screw is smaller than the inner diameter of the main female screw portion 7, and has a circular cross section. The imaginary line connecting the threads (or valleys) of the main female thread portion 7 is a straight line parallel to the screw axis, but the imaginary line connecting the tip or root diameter of the threads of the reduced-diameter female thread portion 8 is the outlet end. A straight line or a curve having a slight inclination closer to the screw axis becomes closer to the tip end of the portion 5, and the degree of diameter reduction becomes larger at the tip end. In the drawings of the present case, the degree of diameter reduction may be exaggerated for ease of understanding, and does not necessarily represent the actual form of the embodiment.

Further, the reduced diameter female screw portion 8 is formed of a little less than three threads, and in the portion of the thread, as shown in FIG. ing. The wavy irregularities 20 are formed continuously over these threads, and between adjacent threads, the convex portions 22 (hereinafter also referred to as loosening preventing convex portions) and the concave portions 24 of the irregularities 20 are respectively formed by the screws. They are formed at positions corresponding to each other on a straight line (vertical plane including the screw axis) crossing the mountain. In addition, the irregularities 20 are formed, for example, at 12 locations in one circumference of the reduced diameter female screw portion 8.

In this embodiment, the starting point of the unevenness 20 is the tip end face of the outlet end 5, and the end point is the plane parallel to the tip end face near the boundary between the reduced-diameter female thread 8 and the main female thread 7. On the other hand, since the screw thread forms a spiral, in the vicinity of the start point and the end point of the unevenness 20, the unevenness 20 does not completely cut the screw thread in the thickness direction. In this sense, the unevenness 20 is formed in a perfect shape with respect to the less than three threads of the reduced diameter female screw portion 8, which is less than two threads.

The projections 22 for preventing loosening of the irregularities 20 project toward the center of the reduced-diameter female screw 8, and the recesses 24 are formed to recede from the center of the reduced-diameter female screw 8. The tip of the anti-loosening projection 22 substantially matches the thread tip of the above-described reduced-diameter female screw portion 8, and the bottom of the concave portion 24 substantially matches the root of the reduced-diameter female screw portion 8. The concavities and convexities 20 are also reduced in diameter by the diameter reduction of the diameter-reduced internal thread portion 8, and as a result, the diameter d1 of the inscribed circle 26 connecting the tips of the plurality of loosening prevention convex portions 22 that repeat continuously in the circumferential direction is:
It is smaller than the root diameter of the bolt to be screwed. On the other hand,
The inscribed circle connecting the bottoms of the plurality of recesses 20 is approximately equal to or larger than the root diameter of the bolt.

The preferable number of the recesses and protrusions 20 (in other words, the number of the protrusions 22 for preventing loosening) provided on the reduced-diameter female screw portion 8 in consideration of the balance between the loosening prevention effect, the tightening torque, and the life of the mold is as follows. Since it differs depending on the average inner diameter d, the thread pitch p of the reduced-diameter female screw portion 8, the presence or absence of hardening, the degree, and the like, it cannot be said unconditionally. For example, FIG.
When the average inner diameter d of the reduced-diameter female screw portion 8 shown in FIG. 1 is used as a reference, it is desirable to determine the size and number of the irregularities 20 so that the pitch s of the irregularities 20 is in the range of 0.1 to 0.5 d.

FIG. 12 shows the operation when the nut 1 having such a structure and the male screw member 13 are screwed together. As shown in (a), when the nut 1 is screwed from the foreign matter removing projection 9 to the main female screw portion 7 to the male screw portion 14 of the male screw member 13 (the male screw member 13 is screwed to the nut 1). In the latter half or near the end of the screwing of the male screw member 13 and the nut 1, the distal end of the male screw member 13 reaches the reduced diameter female screw portion 8 as shown in FIG.

Thereafter, the diameter d1 of the inscribed circle 26 of the plurality of loosening prevention convex portions 22 in the reduced diameter female screw portion 8 (FIG. 10)
(A)) is smaller than the root diameter of the male screw member 13, so that the nut 1
The plurality of loosening prevention convex portions 22 of the reduced diameter female screw portion 8 of FIG.
As described above, the abutment 22 contacts the valley bottom 27 of the male screw portion 14 at a number of positions in the circumferential direction, and the anti-loosening projection 22 and the valley bottom 27 exert a pressing force on each other. Therefore, the locking stopper 22 is elastically compressed, but since the recess 24 is provided at both ends of the locking stopper 22, conceptually, the compressed flesh of the locking stopper 22 is provided on both sides. Easy to escape. That is, the compressive force acting on the anti-loosening convex portion 22 in the diametrically outward direction is applied to the concave portions 2 on both sides.
4 is easy to disperse, so that an excessive increase in torque at the time of screwing is suppressed as compared with the case where there is no unevenness 20, and after the screwing is completed, the plurality of loosening prevention convex portions 22 and the valley bottom 27 are in good pressure contact. A function to prevent loosening is achieved. FIG. 12 (c)
This is the case.

In addition, as the reduced diameter female screw portion 8 and the male screw portion 14 of the nut 1 are screwed together while exerting a pressing force between the fastening projection 22 and the root 27, the reduced diameter female screw portion 8 is formed. Usually, the inner diameter is elastically expanded to some extent. In this case, the inner diameter taper angle of the reduced diameter female screw portion 8 may be reduced by a predetermined amount from α2 to α3 in FIG. In this state, a circumferential tensile force acts on the reduced-diameter female screw portion 8, and this tensile force acts as a pressing force on the root 27 of the male screw portion 14 via a number of tightening convex portions 22, thereby acting. A sufficient loosening prevention effect is exhibited without causing excessive tightening torque or seizure.

As the reduced-diameter female screw portion for preventing loosening, for example, Japanese Patent Application Laid-Open No. Sho 55-30593 and Japanese Patent Publication No. 3-319
26, that is, by caulking the outlet end of the nut at a plurality of locations from the outside, and forming a plurality (for example, three) of convex portions (reduced diameter female screw portions) for preventing loosening on the inner periphery of the female screw. ) Can be adopted in the present invention. FIG. 30 shows a case where the female thread is formed by projecting inward.
1 shows a locking nut 101 having a plurality of convex portions 102. However, in the case of this configuration, the protrusions 102 formed by caulking a plurality of portions of the nut locally may have variations in their positions and dimensional accuracy. Also,
The locally protruding projection and the male thread of the bolt are pressed against each other, causing excessive friction, requiring extremely large torque for tightening and seizure when tightening with a power wrench. is there. Therefore, the structure shown in FIG. 12 and the like is more preferable because the dimensional accuracy is high and seizure during tightening is unlikely to occur.

Next, a method of manufacturing the female screw portion and the reduced diameter female screw portion of the female screw member of the nut 1 will be described. For example, as shown in FIG. 26 (a), first, a nut material is set in a forging die, and a well-known forging operation is performed to form an outer surface thereof and a main female screw for forming a main female screw portion 7 therein. The pilot hole 70 and the outlet side female screw pilot hole 72 having the irregularities 20 (FIG. 10B) are formed simultaneously. At this time, the position of the tip of the fastening convex portion 22 of the unevenness 20 is set at the crest of the female screw to be processed later, that is, the main female screw pilot hole 7.
0, so that the position of the bottom of the recess is substantially equal to the bottom of the female screw to be processed later.

Next, the female screw 74 is cut continuously by a known method such as a tap into both the main female screw pilot hole 70 and the outlet-side female screw pilot hole 72 of the intermediate product N1. As a result, the threaded portion of the outlet end 5 has unevenness 20 overlapping the thread.
(FIG. 10B) is formed all around.

Further, the threaded intermediate product N2 is pressed by a press die 82 as shown in FIG. 27A, for example, to reduce the diameter of the outlet side end portion 5. Here, the taper angle θ1 of the tapered outer peripheral surface 6 ′ of the outlet side end portion 5 of the nut 1 before diameter reduction is formed smaller than the taper angle θ2 of the nut 1 after diameter reduction shown in FIG. By crimping the tapered outer peripheral surface 6 'of the intermediate product N2 with the press surface 83 formed corresponding to the taper angle θ2, the tapered outer peripheral surface 6 of the nut 1 as a final product is formed as shown in FIG. Is plastically deformed to a taper angle θ2. As a result, the outlet end 5 is reduced in diameter.

As another method of manufacturing the nut 1, as shown in FIG. 26 (b), an outlet side female screw pilot hole 72 having the irregularities 20 (FIG. 10 (b)) is formed first by forging. Next, it is also possible to use a method in which the main female screw pilot hole 70 is removed with a press, followed by thread cutting and diameter reduction. Also,
(C) As shown in FIG.
Is formed by penetrating in the axial direction,
It is also possible to form an outlet-side internal thread pilot hole 72 having a zero, and then process the threads through the thread pilot holes 70 and 72 in this order.

The concave and convex shape of the reduced-diameter female screw portion 8 is as follows.
The trapezoidal irregularities 92 as shown in FIG. 28A (strictly speaking, the tip surface of the trapezoidal convex portion is an arc-shaped concave surface, and the total sum of the intermittent individual thread areas s1 for one revolution is 1 For example, if the circumference is composed of continuous threads, for example, 1/3
以下 or less), triangular irregularities 9 as shown in FIG.
4 can also be used.

The present invention is not limited to nuts, but can be widely applied to members having a female screw structure. For example, as shown in FIG. 29 (a), a plurality of female screw portions 9 having a plurality of convex locking functions formed on a frame member 95.
6, the diameter of the outlet side end is reduced, and the thread of the female screw on the inner periphery thereof is provided with irregularities, whereby the same effect as the nut 1 can be obtained. Further, as shown in FIG. 29B, the present invention can be similarly applied to a pipe-shaped female screw member 97. A portion in the figure corresponds to the structure of the female screw portion 14 and the reduced-diameter female screw portion 8 described above.

(Embodiment 2) FIGS. 14A and 14B show
FIG. 9 shows a nut 150 having a coating film peeling function or a dust removing function and a loosening preventing function as an embodiment according to the second configuration of the female screw member of the present invention. The same parts as those of the nut 1 of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. In the nut 150, the edge 10a of the paint film peeling surface 10 functions as an edge or a blade portion for scraping the paint film layer attached to the male screw portion. FIG.
As shown in the figure, the first line (on the side of the bearing surface 2) of the projections 9 for removing foreign matter has a distance R from the central axis O to the inner edge 9b of itself in a plane perpendicular to the central axis O of the spiral.
However, a relief portion 30 is formed so as to increase continuously from the leading end of the spiral (the coating film peeling surface 10) toward the end of the spiral.

As described above, in the first line of the projection 9,
Since the escape portion 30 is formed, as shown in FIG. 16, only the vicinity of the leading end of the protrusion 9 for removing foreign matter comes into contact with the coating film P or the like adhered to the male screw portion 14 of the male screw member 13. As a result, the contact portion between the foreign matter removing projection 9 and the coating film P or the like is reduced. Thereby, the projection 9 for removing foreign matter can be advanced while suppressing the frictional resistance of the coating film P or the like.

Next, as shown in FIG.
The distance R from the center axis O of the spiral to the inner edge 9b thereof is continuously increased at a substantially constant rate ΔR per unit rotation angle λ about the center axis O. In this case, at the screw leading end 10b, the distance R is R0.
However, if it moves by a unit rotation angle λ along the helix from there, R = R1 = R0 + ΔR, and R = R2 = R0 + 2 at 2λ.
When ΔR and 3λ, R = R3 = R0 + 3ΔR. FIG.
As shown in FIG. 8, the escape portion 30 has the above-mentioned distance R continuously increasing at a predetermined rate up to a predetermined rotation angle λ1 about the center axis O, and a constant distance R in an angle section thereafter.
It may be formed so as to be 1. Note that FIG.
FIG. 18 shows an example in which the inner edge 9b is formed in an arc shape or another curved shape in a section up to the rotation angle λ1.
(B) shows an example formed similarly in a straight line.

In the above embodiment, the coating film peeling surface 10 rises substantially perpendicularly to the tangential direction of the inner peripheral surface. However, the angle between the coating film peeling surface 10 and the tangential direction of the inner peripheral surface is set as follows.
It is also possible to form an obtuse angle or an acute angle within a range that does not hinder the peeling of the coating film or the like.

As shown in FIG. 17 (b), the inner edge 9b of the foreign matter removing projection 9 (or the tangent plane P at the screw leading end 10b) at the screw leading end 10b and the coating film peeling surface 10 are separated from each other. Makes an acute angle, the cutting effect on foreign matter such as a coating film can be enhanced. In this case, the angle φ is desirably adjusted in the range of 70 to 80 °. If the angle φ is too small, the die life may be shortened when the screw leading end 10b is manufactured by die forging.

In the above-described embodiment, the relief portion 30 is formed on the first line of the three foreign matter removing projections 9, but the relief portion 30 is formed on the second or third foreign matter removing projection 9 as well. Can be formed.

(Embodiment 3) FIGS. 19 and 20 show a female screw member according to a third embodiment of the present invention, which has a coating film peeling function or a dust removing function and a loosening preventing function. The nut 200 is shown. The same parts as those of the nut 1 of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. In the nut 200, foreign substances are removed at substantially equal angular intervals at three positions in the circumferential direction, adjacent to the leading end side in the screwing direction of the main female screw portion 7 formed on the hexagonal portion 3 side. A foreign matter removing female screw portion 40 is formed as the foreign matter removing projection 9. As shown in FIG. 21A, three (three) thread segments 41, 4 arranged in the axial direction are provided on the respective foreign matter removing female screw portions 40.
2, 43 are formed, and this thread segment 4
The heights of 1, 42, and 43 gradually decrease from the main female screw portion 7 toward the seat surface 2 side. FIG. 21 (b)
The thread segments 41 to 43 of the foreign matter removing female screw part 40 formed at three places are represented in a straight line, and the horizontal axis shows the length of the foreign matter removing female screw part 40 and the vertical axis shows the height from the screw hole. Things. The third thread segment 43 is
The height is almost the same as that of the main female screw portion 7.

As shown in FIG. 22, when the male thread 14 of the male thread member 13 such as a bolt and the nut 1 are screwed together, the foreign matter removing female thread 40 is provided with an external thread prior to the main female thread 7. The male screw part 14 of the member 13 is screwed. At this time, in order to remove the coating film and the like adhered to the male screw portion 14, as shown in FIG. 23, when the male screw member 13 is screwed in the screwing direction, as a first step, the foreign matter removing female screw portion 40 is formed. A predetermined amount of the coating film P1 or the like is removed by the coating film peeling surface 10 of the thread segment 41 formed on the thread segment 41, and the coating film P2 or the like remaining in the first step of the removal process in the second stage is removed.
The film is further partially removed at the second coating film peeling surface 10. In the third stage, the coating is removed at the third thread segment 43. Since the thread segment 43 has almost the same height as the main female screw portion 7, the remaining coating film is removed. Almost all of P3 and the like can be removed on the coating release surface 10. The coating film thus removed is shown in FIG.
Is stored in the coating film pool 11 in the same manner as described above.

As shown in FIG. 24A, the heights of all the thread segments may be different from each other. In the figure, a total of nine thread segments 44 to 52 of the foreign matter removing female screw portion 40 formed at three places are
An example is shown in which the height is increased in nine steps from the seat surface side. FIG. 24B shows the thread segments 44 to 44.
For 52, the length of each foreign matter removing internal thread 40 (horizontal axis)
And the height (vertical axis). In this way, by further subdividing the amount of change in height between the thread segments 44 to 52, the resistance associated with the removal of the coating film or the like can be further reduced, and thus the screw can be tightened more smoothly. . In this embodiment,
Although a case has been described where each part of the foreign matter removing internal thread portion 40 separated by the foreign material reservoir 11 includes three thread segments, the number of thread segments is not limited to this. In the case where the foreign material accumulation portion 11 is not formed in the foreign material removing female screw portion 40, the height of the female screw thread can be continuously changed as shown in FIG.

Further, as shown in FIG. 25, the foreign matter removing female screw portion 40 can be formed in a tapered shape whose diameter decreases toward the main female screw portion 7 side. In the foreign matter removing female screw portion 40, specifically, the thread segments 60 to 62 are formed at substantially the same height in the tapered pilot hole T. As a result, the amount of protrusion of the thread segments 60 to 62 with respect to the screw hole 12 of the main female screw portion 7 becomes smaller from the main female screw portion 7 side toward the seat surface 2 side. In FIG. 25, the inclination of the taper is slightly exaggerated for convenience of explanation.

[Brief description of the drawings]

FIG. 1 is a front view and a sectional view of a nut according to a first embodiment of the present invention.

FIG. 2 is a perspective view of the nut from a seat surface side.

FIG. 3 is a diagram showing a bottom surface of the nut.

FIG. 4 is a sectional view of a modification of FIG. 1;

FIG. 5 is a partial cross-sectional view showing a threaded state of the male screw member and the nut.

FIG. 6 is an explanatory diagram of an operation at the time of screwing.

FIG. 7 is an explanatory view when a guide portion is formed on a seat surface side of a nut.

FIG. 8 is an explanatory diagram in the case where another guide portion is formed.

FIG. 9 is a bottom view in the case where the second concave portion is formed intermittently in the circumferential direction.

10 is a cross-sectional view and a plan view taken along line CC of FIG.

FIG. 11 is a diagram showing an inner diameter, a pitch of unevenness, and a thread pitch of a reduced-diameter female screw portion.

FIG. 12 is an explanatory diagram of an action of preventing loosening due to elastic deformation of an outlet side end when screwed with a male screw member.

FIG. 13 is an explanatory diagram of an effect of unevenness of a reduced-diameter female screw portion.

FIG. 14 is a perspective view of a nut according to a second embodiment of the present invention and a partially enlarged view thereof.

FIG. 15 is a diagram showing a bottom surface of the nut.

FIG. 16 is a plan sectional view showing a screwed state of the nut and the male screw member.

FIG. 17 is a view showing the vicinity of a leading end of a foreign matter removing projection of the nut.

FIG. 18 is a diagram showing a modification of FIG. 18;

FIG. 19 is a perspective view of a nut according to the third embodiment.

FIG. 20 is a diagram showing a cross section and a bottom surface of the nut.

FIG. 21 is a diagram showing a cross section of a foreign matter removing internal thread portion.

FIG. 22 is a partial cross-sectional view showing a screwed state between the nut and a male screw member.

FIG. 23 is an explanatory diagram of the operation when the nut is screwed.

FIG. 24 is a view showing a modification of the foreign matter removing female screw portion.

FIG. 25 is a diagram showing a case where the foreign matter removing female screw portion is formed in a tapered shape.

FIG. 26 is a diagram illustrating a method for manufacturing the female screw portion and the reduced-diameter female screw portion of the nut according to the present invention.

FIG. 27 is a view for explaining the diameter reducing step.

FIG. 28 is a view showing another uneven shape of the reduced-diameter female screw portion.

FIG. 29 is a view showing still another embodiment of the nut of the present invention.

FIG. 30 is a view showing a modification of the reduced-diameter female screw portion.

[Explanation of symbols]

1, 16, 18, 150, 200 Nut (female screw member) 2 Seat surface 3 Hexagonal part 5 Exit side end part 7 Main female screw part 8 Reduced diameter female screw part 9 Convex part for removing foreign matter (foreign matter removing part) 10 Paint peeling surface DESCRIPTION OF SYMBOLS 11 Coating film accumulation part, 1st recessed part (foreign matter accumulation part) 17 Cylindrical guide part 19 2nd recessed part (foreign matter accumulation part) 20, 92, 94 Irregularities 22 Loosening prevention convex part 24 Concave part 30 Escape part 40 Foreign matter Removed internal thread 41-52 Thread segment

Claims (14)

[Claims] An internal thread portion is screwed to the external thread portion of the external thread member, and the external thread portion is threadedly engaged with the external thread portion to remove foreign matter such as a coating film attached to the external thread portion. In the foreign matter removing portion formed at the leading end in the direction, or in the screwing, the foreign matter formed on the foreign matter removing convex portion screwed with the male screw portion adjacent to the leading end side of the female screw portion is removed. A foreign matter removing portion for removing the foreign matter attached to the external thread portion by the foreign matter removing portion, and a foreign matter accumulation portion for storing the removed foreign matter,
The inner peripheral surface of the female screw portion is formed in a region on the leading side in the screwing direction from the female screw portion, and the female screw portion with respect to the male screw member has an outlet of an inlet side end and an outlet side end of the screwing. A female screw characterized by forming a reduced-diameter female screw portion for preventing loosening by reducing the diameter of the side end in at least a part of the circumferential direction so that the inner diameter of the female screw there is smaller than that of the intermediate portion. Element. 2. The foreign matter removing portion is formed in the foreign matter removing convex portion provided in a region further preceding the leading end of the female screw portion in the screwing direction, and the foreign matter removing convex portion is provided. Are provided at a predetermined interval, and the foreign substance accumulation portion is a first recessed portion deeper than a threaded hole diameter of the female screw portion on an inner peripheral surface between the foreign matter removing convex portions in the preceding region. The female screw member according to claim 1, wherein the female screw member is formed as: 3. A non-thread forming portion having a fixed width is provided on an inner peripheral surface of the female screw portion on a leading side in the screwing direction, and the non-thread forming portion is formed into a cylindrical shape at the time of starting screwing with the male screw portion. The female screw member according to claim 1, wherein the female screw member is a guide portion, and the non-thread forming portion is the foreign matter accumulation portion. 4. A non-screw forming portion, wherein a plurality of second recesses deeper than the threaded hole diameter of the female screw portion are formed intermittently in the circumferential direction or continuously in a ring shape, The female screw member according to claim 3, wherein the forming portion and the second concave portion serve as the foreign matter accumulation portion. 5. A female screw part having a female screw part with which the male screw part of the male screw member is screwed, and the female screw part being screwed together to remove foreign matter such as a coating film attached to the male screw part. The foreign matter removing portion formed at the leading end in the direction, or the foreign matter for removing the foreign matter formed on the convex portion which is located on the leading end side of the female screw portion and is screwed with the male screw portion in the screwing. The female screw portion or the foreign matter removing convex portion has a removing portion, and at least a section from the leading end of the spiral where the foreign matter removing portion is formed to a predetermined position on the spiral. Along a part of the portion, in a plane orthogonal to the center axis of the female screw portion, the distance from the center axis to its inner edge is
A relief portion that is larger than the distance from the center axis to the inner edge of the foreign matter removing portion is formed, and the inlet side end portion and the outlet side end portion of the screwing of the female screw portion to the male screw member. The inner diameter of the outlet side is reduced in at least a part of the circumferential direction so that the internal diameter of the internal thread is smaller than that of the intermediate portion, thereby forming a reduced-diameter internal thread portion for preventing loosening. Female screw member. 6. The relief portion is continuously or stepwise so that the distance from the center axis to the inner edge of the relief portion is away from the leading end of the spiral along the spiral of the female screw portion or the foreign matter removing convex portion. 6. The female screw member according to claim 5, wherein the female screw member is formed so as to be larger in size. 7. The foreign matter adhering to the male screw portion is removed by the foreign matter removing portion, and the foreign material storing portion for accommodating the removed foreign matter is screwed in the screwing direction from the female screw portion on its inner peripheral surface. 5. The method according to claim 5, wherein the region is formed in a region on the leading side of
Or the internal thread member according to 6. 8. A male female threaded part having a main female threaded part, the main female threaded part being attached to the male threaded part of the male threaded member so as to be located at the leading end side in the screwing direction with the male threaded member to be screwed to the main female threaded part. A foreign matter removing female screw portion for removing foreign matter such as a coated film is formed, and the female screw thread of the foreign matter removing female screw portion is
In the section from the leading end of the spiral to the predetermined position,
The inner diameter is formed so as to increase continuously or stepwise toward the leading end of the foreign matter removing female screw portion, and the inlet side end portion and the outlet side end portion of the screwing of the female screw portion to the male screw member. The outer diameter of the outlet side is reduced in at least a part of the circumferential direction so that the inner diameter of the internal thread is smaller than that of the intermediate part, thereby forming a reduced-diameter internal thread for preventing loosening. A female screw member characterized by the above-mentioned. 9. The foreign matter removing female screw portion is notched radially at an intermediate portion in a circumferential direction, so that a foreign matter collecting portion for accommodating foreign matter removed by the foreign matter removing female screw portion has a concave shape. The female screw member according to claim 8 formed. 10. The one or more foreign matter accumulating portions are formed in a circumferential direction of the foreign matter removing female screw portion, whereby the foreign matter removing female screw portion is divided into a plurality of thread segments arranged in the screwing direction. The height of the thread segments decreases stepwise in units of one or a plurality of the thread segments as they approach the leading end side in the screwing direction of the external thread portion. The internal thread member as described in the above. 11. The reduced-diameter female screw portion is formed by reducing the diameter of the outlet-side end portion of the female screw portion over the entire circumference, and the thread of the reduced-diameter female screw portion is formed as irregularities that are continuously repeated in the circumferential direction. The convex portion (hereinafter referred to as a loosening preventing convex portion) protrudes toward the center of the reduced-diameter female screw portion, and the concave portion is formed so as to recede from the center side of the reduced-diameter female screw portion. The diameter of the inscribed circle connecting the tips of the stop projections is smaller than the root diameter of the male screw member screwed to the female screw portion, and the female screw member is screwed to the female screw portion, and the reduced diameter female screw is The plurality of anti-loosening protrusions having irregularities in the thread of the portion press against the root of the male screw member and tighten the male screw member from the outer periphery in a state where the male screw member is elastically compressed by the reaction. Female screw described in any of Wood. 12. The unevenness of the thread of the reduced-diameter female screw portion,
The female screw member according to claim 11, wherein the female screw member is formed in a form of waving in an arc shape. 13. The unevenness of the screw thread of the reduced-diameter female screw portion,
13. The triangular shape in which the anti-loosening projection is widened from its distal end to its proximal end in plan view.
6. The female screw member according to claim 1. 14. The unevenness of the screw thread of the reduced-diameter female screw portion,
While being formed continuously over a plurality of threads, the concave and convex concave portions and the loosening prevention convex portions of the unevenness are formed between adjacent threads at positions corresponding to each other on a straight line traversing the threads. The female screw member according to any one of claims 11 to 13.