JP2015155706A - Thread part coupling structure with looseness preventive function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide this invention in reference to conventional clear analyzed facts that a load applied to each of threads in a metric thread when a thread is connected and fixed shows a high value at the first thread of a fastening side under analysis by a finite element method or research and study performed by official institutes, so a stress concentration part becomes a starting point of breakage at the time of fastening of the thread and a surface slippage occurs during fastening of the thread surface to produce a looseness of the thread.

SOLUTION: This invention provides a screw having superior breakage preventive and fatigue preventive characteristics and realizing looseness preventive effect by a fastening method similar to a usual screw by setting a structure in which a size of screw thread of a male thread becomes maximum part 2 at one end and becomes minimum part 3 at the other end while holding an axis line, and by displacing the male thread to the other end under application of an axial force and making a structure of the thread part in which it is not easily released or moved by application of an external force in a direction perpendicular to an axis.

COPYRIGHT: (C)2015,JPO&INPIT

Description

The present invention relates to a fastening structure that is excellent in improving seismic safety and used for joining residential building structural members and fastening automobile parts, and that greatly shortens the fastening work time.

Screws are widely used for joining civil engineering and building structures, automobiles, and construction machinery. Among them, particularly in places where safety is required, it is fastened with various slack prevention products.

In order to prevent looseness, it is better to fit the male thread and female thread with as little gap as possible.However, if there is not enough clearance, the screw will not fit well, and there will be frictional resistance. It becomes impossible to provide a gap at all because it becomes large and difficult to work.

The present patent application Japanese Patent Application No. 2014-004830 of the inventor of the present application is not a screw thread of a male screw or a female screw having the same shape on the entire circumference, but a screw thread that repeats expansion and contraction every half circumference. The product may be difficult to loosen against external force in the direction perpendicular to the axis, but when the external force is generated in the axial direction because the male screw and female screw are in contact only on the side where the thread is the largest, Since the shear load is concentrated, there may be a problem in the strength of the thread.

Japanese Patent Application No. 2014-004830

An object of the present invention is to provide a fastening structure that exhibits a loosening-preventing effect even with a fastening method similar to that of a normal male screw or female screw at the time of screw fastening, and particularly solves the problem of loosening due to an external force in the direction perpendicular to the axis.

Claim 1 of the present invention is the structure of the thread portion of the male screw, wherein the spiral of the screw thread is not the same size on the entire circumference, and the spiral repeats expansion and contraction once in one turn. The side where the maximum is located is parallel to the shaft, and when the axial force is applied to the shaft of the male screw during fastening, it contacts the pressure side flank surface of the female screw as soon as possible. One of the female threads moves obliquely with respect to the shaft, and the side where the thread that exists parallel to the shaft is minimized is the contact between the male screw and the pressure side flank surface of the female screw. On the side where the height and width of the screw thread are maximized, the metric thread standard dimension (hereinafter referred to as the standard dimension) is approximately the same as or larger than that of the male thread, and on the minimum side, it is smaller than the standard dimension. The part between them is the maximum The width of the thread and the lead are the same as the standard size of the corresponding nominal diameter male thread. The tangent line between the screw thread and each flank surface approaches the center of the screw thread, moves away from it, and repeats meandering as the screw thread repeatedly expands and contracts. It is a fastening structure of a threaded portion of a male screw characterized by being widest.

Claim 2 according to the present invention is a fastening structure of a threaded portion of a nut, wherein the mechanism of the threaded portion of the male thread of Claim 1 is realized in the nut, and the thread groove has the same shape all around. The feature is that expansion and contraction are repeated once each time the spiral makes one turn, and the thread is the metric thread standard dimension (hereinafter referred to as the standard dimension) on the side where the groove of the thread that exists parallel to the axis is the smallest. However, on the side where the groove of the thread that exists parallel to the axis is the largest, the groove is deep and wide, so the root of the thread is It is located farthest away, and the width of the top of the screw thread is narrow and smaller than the quarter length of the pitch of the female screw of the standard dimension, and is about one eighth of the pitch length of the male thread of the standard dimension. , On the side with the smallest and largest thread groove The part is the size of the process of continually changing the size of the groove from one size to the other, and when tightening with the male screw, the pressure side flank surface of the screw thread on the side where the groove is minimum is Since the earliest contact with the pressure side flank surface of the male screw is the fastest, either the male screw or the female screw will move obliquely with respect to the axis along the inclination of the thread, and the side where the groove is the largest will cause this pressure to It is the structure of the thread part of the internal thread characterized by a side flank surface contacting.

The thread portion of the male screw according to the first aspect of the present invention is not uniform in thread size, and even if an external force in the direction perpendicular to the axis is generated and the screw is inclined, the thread is small on the side where the thread is minimized. Therefore, there is a limit to pushing out the screw in the direction in which the screw thread of the male screw is loosened, and on the side where the screw thread is maximized, the screw thread is pushed out in the direction in which the axis of the male screw and female screw is further displaced, making it difficult to loosen. Even if the screw is inclined in a direction perpendicular to the line connecting the maximum side and the minimum side, the axis of the male screw and the female screw is shifted, so that it is difficult to shift in the direction in which the force is relaxed and loosened.

The threaded portion of the female screw according to claim 2 of the present invention has a structure in which the axis of the male screw and the female screw is displaced and fixed at the time of fastening. Hateful.

The figure explaining the shape of the thread part of the external thread of Example 1 of this invention The figure explaining the cross-sectional shape of the thread part of the external thread of Example 1 of this invention The figure explaining the mechanism of fastening of the screw part of the external thread of Example 1 of the present invention The figure explaining the shape of the thread of the thread part of the external thread of Example 2 of this invention The figure explaining the shape of the thread of the thread part of the external thread of Example 3 of this invention The other figure explaining the shape of the thread of the thread part of the external thread of Example 4 of this invention The figure explaining the shape of the thread part of the tapping screw of Example 5 of this invention The figure explaining the shape of the thread part of the internal thread of Example 6 of this invention The figure explaining the mechanism of the fastening of the thread part of the internal thread of Example 6 of this invention The other figure explaining the cross-sectional shape of the thread part of the internal thread of Example 6 of this invention

In addition to providing products with excellent fracture resistance and fatigue resistance, the size of the thread groove of the male screw or female screw is the same as the axis for the purpose of providing a screw that exhibits a locking effect by the same fastening method as a normal screw. A screw is used that has a structure in which expansion and contraction are performed once every time the spiral makes a round, and the axis of the male screw and the female screw is shifted during fastening.

An embodiment of a male screw according to the present invention will be described in detail below based on the drawings.

As shown in FIG. 1 and FIG. 2, claim 1 according to the present invention is the structure 1 of the thread portion of the male screw, and the spiral of the screw thread is not the same size on the entire circumference, and the spiral expands and contracts within one round. The screw 2 that repeats once, the side 2 on which the thread 11 is maximum is located parallel to the shaft 7, and as shown in FIG. 3, when the axial force is applied to the shaft portion of the male screw 20 when fastened, the female screw 21 is fastest. The side that contacts the pressure side flank surface, and either the external thread or the internal thread moves obliquely with respect to the shaft along the inclination of the flank surface of the thread, and the thread that exists parallel to the shaft is minimized. 3 is characterized in that the pressure-side flank surfaces of the male screw and the female screw come into contact with each other by this displacement, and the male screw of the metric screw reference dimension 4 (hereinafter referred to as the reference dimension) is on the side where the height and width of the screw thread are maximum. As small as the thread size or larger, minimum On the side that becomes smaller than the reference dimension, the portion between them is the size of the process that gradually changes from one side to the other with the maximum side and the minimum side as extremes, The pitch and lead are the same as the standard dimensions of the corresponding nominal diameter male thread, and the tangent line 5 of the thread and each flank surface approaches or moves away from the center of the thread as the thread repeatedly expands and contracts. Repeating meandering, the thread bottom 6 has the widest width on the smallest side, and is a fastening structure for a threaded portion of a male screw.

According to the first aspect of the present invention, when the groove for making the male screw thread is formed in the flat die for producing the screw portion of the present invention, it is designed so that only the difference between the shallow digging and the deep digging is required.

In claim 1 according to the present invention, the smallest thread is not less than 50 percent of the largest thread and not less than 50 percent.

The side where the screw thread is maximized may be one point on the circumference as in the first embodiment according to the present invention, and may occupy a certain percentage of the circumference as shown in FIG. Less than half.

According to the present embodiment, there is a possibility that when the fastening operation is performed, it is possible to suppress the screw from being inclined or rattling more than necessary to the same extent as a normal screw.

The side where the screw thread is minimized may be a single point on the circumference as in the first embodiment of the present invention, but may occupy a certain percentage on the circumference as shown in FIG. Is 1/3 or less.

When this embodiment is used, there is a possibility that the performance of preventing loosening is more exhibited.

As shown in FIG. 6, the screw thread on the side where the screw thread is maximum may be larger than the reference dimension, but in this case, it is necessary to make the upper limit tolerance of the diameter of the screw shaft smaller than the value determined by the reference dimension. There is.

In the present invention, because of the relationship of shifting when the male screw or female screw is fastened and fixed, the catch rate is low on the side where the screw thread becomes maximum, and there is some concern about insufficient strength. A method of increasing the size is also conceivable.

The screw of claim 1 or claim 2 according to the present invention can be used as a tapping screw if the shaft tip is a tapping screw specification as shown in FIG.

When used as a tapping screw, as shown in FIG. 7, only the portion 8 having a sharp tip is required to have the same thread as that of a normal tapping screw, and the other portion 9 needs to be the thread of the present invention.

Although FIG. 7 shows a single-type tapping screw, it is possible to use two or three types of tapping screws. In that case, the portion where the tip shaft is tapered may be a normal screw thread. In the case where it is not possible to smoothly shift to the thread of the present invention by only the pointed portion in FIG. 1, although not shown in the drawing, the periphery of the shaft is tapered by one or two threads following the pointed portion, and the portion is a normal thread. And then connected to the original shaft diameter provided with the thread of the present invention.

As shown in FIG. 8, claim 2 according to the present invention is a fastening structure of a screw portion of a nut, and the mechanism of the screw portion of the male screw of claim 1 is realized in the nut. Although it has the same shape on the circumference, the expansion and reduction are repeated once each time the spiral makes one revolution, and the thread 11 on the side 10 where the groove of the thread existing parallel to the axis is the smallest is It has the same shape as a female thread of a metric thread reference dimension (hereinafter referred to as a reference dimension), but the groove is deep and wide on the side 12 where the groove of the thread that exists parallel to the axis is the largest, The root 6 of the screw is located farthest from the axis, the width 14 of the top of the screw thread is narrower than the quarter length of the pitch of the female screw of the standard dimension, and the length of the pitch of the male thread of the standard dimension is 8 minutes. The thread groove is characterized by The portion between the minimum side and the maximum side is the size of the process in which the size of the groove gradually changes from one size to the other, and when fastening with a male screw, it is shown in FIG. Since the pressure side flank surface of the thread on the side with the smallest passage groove hits the pressure side flank surface of the male screw earliestly, either the male screw or the female screw moves obliquely with respect to the axis along the inclination of the thread, This is the structure of the threaded portion of the female screw, wherein the pressure side flank surface of the male screw and the female screw comes into contact with each other on the side where the groove is maximum.

In the nut manufacturing method of the present embodiment, it is necessary to shift the positions of the nut center 16 and the vent tap center 17 as shown in FIG.

The nut manufacturing method of the present embodiment is such that a thread is provided on the vent tap 15 in accordance with the size of the groove on the side 12 where the thread groove is maximum, and the screw is formed on the side 11 where the thread groove is minimum. Use only the edge of the mountain.

The male and female threads having the thread structure of the present invention should not be used at the same time, but in combination with male or female threads of standard dimensions.

The nut of the present embodiment may be used as a double nut, and the double nut makes it more difficult to loosen.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and it goes without saying that the present invention can be implemented in various modes without departing from the gist of the present invention.

The fastening member of the present invention can be widely used as a fastening member or a fastening structure in a vehicle, various devices, buildings, and the like.

1 Thread structure of male thread 2 Side where screw thread is maximized 3 Side where thread is minimized 4 Metric thread reference dimension 5 Tangent line of thread and each flank 6 Screw root 7 Axis 8 Axis pointed Part 9 Other part 10 Side where thread groove is minimum 11 Screw thread 12 Side where thread groove is maximum 14 Thread apex width 15 Vent tap 16 Nut center 17 Vent tap center 19 thread Groove 20 male screw 21 female screw 22 position before moving screw

Claims (2)

This is the structure of the threaded part of the male screw, and the spiral of the screw thread is not the same size all around, but the screw repeats expansion and contraction once in one turn. When the axial force is applied to the male screw shaft when fastened and fixed, it contacts the pressure side flank surface of the female screw as soon as possible, and either the male screw or the female screw is against the shaft along the inclination of the flank surface of the thread. It is characterized by the fact that the side of the screw thread that exists parallel to the axis and has the smallest screw thread is the contact between the male and female screw pressure-side flank surfaces. On the maximum side, the metric thread reference dimension (hereinafter referred to as the reference dimension) is equal to or larger than the thread size of the male thread, and on the minimum side, it is smaller than the reference dimension, and the portion between them is maximum. The side and the smallest side It is the size of the process that changes gradually from one size to the other as an extreme, and the thread pitch and lead are the same as the standard dimensions of the corresponding nominal diameter male thread. The male thread is characterized in that the thread bottom is the widest on the smallest side, as the tangential line approaches the center of the thread, moves away, and repeats meandering as the thread repeats expanding and contracting. Fastening structure of screw part. A nut fastening structure, wherein the mechanism of the threaded portion of the male screw according to claim 1 is realized in the nut, and although the thread groove has the same shape on the entire circumference, expansion and contraction are performed while the spiral makes one turn. The thread has the same shape as the thread of the female thread of the metric thread reference dimension (hereinafter referred to as the reference dimension) on the side where the thread groove that exists parallel to the axis is the smallest. However, on the side where the thread groove that is parallel to the axis is the largest, the groove is deep and wide, so the root of the thread is located farthest from the axis and the top of the thread is The width of the screw thread is narrower and smaller than one quarter of the pitch length of the female screw of the standard dimension, and about one eighth of the pitch length of the male thread of the standard dimension, and the side where the groove of the screw thread is minimized The portion between the largest side and the largest side gradually increases from one to the other This is the size of the process in which the size of the groove continuously changes.When tightening with a male screw, the pressure side flank surface of the screw thread on the side where the groove is minimum is the earliest pressure side flank surface of the male screw. Therefore, either the male screw or the female screw moves obliquely with respect to the axis along the inclination of the thread, and the pressure side flank surface of the male screw and the female screw comes into contact with each other on the side where the groove is maximum. The structure of the threaded part of the female screw.