JPH06200916A - Release preventing nut and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a release preventing nut having stable release preventing effect with a nut unit, and provide a method for manufacturing the release preventing nut at a low cost. CONSTITUTION:A release preventing nut is formed in such a way that annular recessed positions 11, 21 are provided on the inner circumferential part of a nut, and also a pitch P2 between tops 14, and 15; 24 and 25 of a screw ridge positioned closely to both sides of adjacent recessed positions 11, 21, or a pitch between roots 16, and 17; 26 and 27 positioned closely to both sides of the recessed positions 11, 21 is made shorter than the pitch P1 of the other screw parts. The release preventing nut is manufactured in a such way as including a tapping process applied to a molding body 80 provided with an annular recessed position 84 on its inner circumferential part, so as to form a female screw 93 of a prescribed pitch P1 on the inner circumferential part of the forming body 80 and a process for pressing a molding body 90 forming the female screw 93 in axial direction, so as to shorten pitch of the recessed position 91 and also shorteuing the pitch between top parts 14 and 15 of the screw ridge positioned closely to both sides of adjacent recessed position 11 or the pitch between roots positioned closely to both adjacent recessed position 11 from the pitch P1 of the other screw part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a loosening prevention nut and a manufacturing method thereof.

[0002]

2. Description of the Related Art Various types of nuts are used for tightening and positioning objects and parts. At the place of assembly, the nut is securely fastened with a predetermined tightening force. However, if a long time has passed after the assembling, the nut may not be loosened and the original tightening force may be lost. In the worst case, the nut itself may fall off. Such a loosening phenomenon becomes a big problem especially in a place where vibration is applied continuously or intermittently.

Therefore, it is very important to prevent the nut from loosening, and various types of loosening prevention measures have been conventionally proposed. Typical examples are given below. 1) Stack two pieces to make a double nut. 2) Make a hole in the male thread and pass a split pin or wire through it. 3) Bend a part of the washer to prevent rotation. 4) Reduce the diameter of a part of the female screw to less than the basic diameter. 5) Attach the resin ring to the nut to eliminate play with the male screw. 6) Form unevenness on the tightening seat surface. Or, use a washer with irregularities. 7) Make the thread of the screw different in shape and prevent it from loosening due to its deforming force. 8) Fix the screw surface with an adhesive. 9) Part of the nut or the ring-shaped plate attached to the nut is crimped to eliminate play with the male screw. 10) A flange is formed integrally with the nut, and the bending force of the flange generated during tightening is used. 11) Use spring washers.

[0004]

The problems of the above-mentioned prior art will be briefly described.

The above 1), 2), 3), 5), 6),
The methods 8) and 11) are expensive because they require special parts and adhesives in addition to the nut.

The above methods 4), 7) and 9) have a large dimensional error at the manufacturing stage, and a stable loosening preventing effect cannot be expected. In addition, cost is high to manufacture with high accuracy.

In the method 6), the surface of the object to be fastened is apt to be scratched, and the anticorrosive treatment applied to the surface may be impaired.

The above methods 5) and 8) cannot be used at a high temperature above a certain level.

The method of 10) is not effective when the hardness of the surface of the object to be fastened is insufficient.

In view of the above problems of the prior art, it is an object of the present invention to provide an anti-loosening nut which can obtain a sufficient anti-loosening effect with a nut alone and can be manufactured at low cost, and a manufacturing method thereof. I am trying.

[0011]

The loosening prevention nut of the present invention is provided with annular recesses 11 and 21 on the inner circumference of the nut, and the tops 14 and 15 of the screw threads located on both sides of the recesses 11 and 21. ;
The loosening prevention nut characterized in that the interval P2 of 24, 25 or the interval of valley bottoms 16, 17; 26, 27 located on both sides of the recesses 11, 21 is shorter than the pitch P1 of the other threaded portions. Is the gist.

In the method of manufacturing the loosening prevention nut of the present invention, tapping is performed on the molded body 80 having the annular recess 84 on the inner periphery to form the female screw 93 having a predetermined pitch P1 on the inner periphery of the molded body 80. And the step of pressing the molded body 90 on which the female screw 93 is formed in the axial direction to reduce the distance between the recesses 91, and the distance between the tops 14 and 15 of the screw threads located on both sides of the recess 11 or the distance between the recesses 11. A gist of a method for manufacturing a loosening prevention nut is characterized by including a step of making an interval between valley bottoms located on both sides shorter than a pitch P1 of other threaded portions.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of a loosening prevention nut of the present invention, and is a sectional view of a left half section, and FIG. 2 is a partially enlarged view of FIG. It should be noted that in FIG. 1, the threads that appear behind the cross section are omitted for the sake of clarity.

Loosening prevention nut 10 (hereinafter abbreviated as nut)
A female screw 13 having a pitch P1 is formed on the inner circumference of the.

An annular recess 11 deeper than the root of the female screw 13 is formed on the inner circumference of the nut 10. Female screw 13
Is discontinuous at the recess 11.

The recess is provided at a distance L from the surface opposite to the seat surface 12, and the distance L is, for example, 1.0 to 1.
It can be set to about 5 times. The diameter R of the recess 11 is preferably 1.5 to 2.0 times the nominal diameter (valley diameter) D of the screw, more preferably 1.6 to 1.8 times, and most preferably 1.6 to
Set to 1.7 times. The thickness T of the recess is the pitch P.
It is preferably set to 0.1 to 1.0 times, more preferably 0.2 to 0.8 times, and most preferably 0.4 to 1.
Set to 0.6 times.

The crests 1 of the threads located on both sides of the recess 11
The interval P2 of 4, 15 or the interval of the valley bottoms 16 and 17 located on both sides of the recess 11 (not shown, this interval is also P2) is shorter than the pitch P1 of the other screw portions.
Now, there is a recess 11 between the peaks 14 and 15 or between the valley bottoms 16 and 17, and the female thread 13 is discontinuous there. Ignoring this discontinuity, the spacing between the thread crests 14 and 15 on either side of the recess 11 or the valley bottom 1 on both sides of the recess 11
If the interval between 6 and 17 is dared to be called a pitch, the pitch can be expressed as follows. That is, recess 1
It can be said that only the pitch P2 straddling 1 is shorter than the pitch (hereinafter also referred to as the basic pitch) P1 of the other screw portions.

The size of the pitch P2 straddling the recess 11 is preferably 0.7 to 0.9 times the basic pitch P1.

By setting the size of the pitch P2 straddling the recess as described above, a stable loosening prevention effect can be obtained, and the nut can be manufactured with high precision.

The size of the nut 10 is JIS B.
It can be appropriately determined according to the 1170 grooved nut.
However, the split pin groove is not necessary in the present invention.

Now, when the nut 10 is screwed into an ordinary male screw, the pitch P2 straddling the recess extends and becomes substantially equal to the basic pitch P1. That is, the nut is deformed so that the distance between the crests 14 and 15 of the screw threads or the distance between the valley bottoms 16 and 17 on both sides of the recess extends, and the pitch is about (P1-P2).
It only grows. It is considered that the corresponding portion on the male screw side also receives reaction force and is deformed to some extent. Considering the deformation on the male screw side, the deformation of the female screw is smaller than the above value. In any case, the bending force generated by the deformation acts between the flank surfaces of the male screw and the female screw to increase the frictional resistance, thereby preventing the nut from loosening.

FIG. 3 is a sectional view showing another embodiment of the loosening prevention nut of the present invention. 1 and 2 for this embodiment.
Only the differences from the embodiment will be briefly described.

The nut 20 shown in FIG. 3 is provided with a belt-like flange 26 on the seat surface 22 side. The annular recess 21 is provided at a distance L from the seat surface 22. This nut 20
In addition to the loosening prevention effect, it also has the effect of relieving the stress concentrated in the vicinity of the seat surface of the mating male screw and the effect of setting a high tightening surface pressure near the outer periphery of the seat surface. When the recess is arranged at a position close to the seat surface as described above, it is possible to obtain a secondary effect that the stress concentration of the mating male screw is relieved and the tightening force can be prevented from lowering.

Next, a method for manufacturing the loosening prevention nut of the present invention will be described with reference to the process diagrams of FIGS.

First, the flow of the manufacturing process will be briefly described as follows.
First, the outer, inner, and end faces are continuously machined by a multistage horizontal press (see FIGS. 4 to 9). Next, a female screw tapping process is performed (see FIG. 10), and finally a pitch shift is generated by press working (see FIG. 11). Hereinafter, each step will be described in detail.

First, the rod is cut to obtain a material 30 having a hexagonal cross section shown in FIG.

A prepared hole 41 having a predetermined depth is formed on one surface of the material 30 to obtain a molded body 40 shown in FIG.

The prepared hole 41 of the molded body 40 shown in FIG. 5 is enlarged, and a prepared hole is also formed on the other surface. By this molding, the molded body 50 of FIG. 6 having the pilot holes 51 and 52 on both sides is obtained. The bottoms of the pilot holes 51 and 52 are defined by a bottom wall 53.

The bottom wall 53 of the prepared holes 51 and 52 is punched out to obtain a molded body 60 shown in FIG. A through hole 61 is formed on the axis of the molded body 60. The through hole 61 has the tapered portion 6
2, a middle portion 63 and a large diameter portion 64.

The wall portion 65 near the end of the large-diameter portion 64 of the molded body 60 is deformed so as to move inward to obtain a molded body 70 shown in FIG. As a result, an annular recess 74 is formed at a position slightly below the middle portion of the through hole 71. The lower portion 75 of the recess 74 is tapered.

The molded body 70 is further molded to obtain a molded body 80 shown in FIG. In the molded body 80, the intermediate portion 83 and the lower end portion 85 straddling the annular recess 84 have the same diameter. Further, the lowermost portion of the lower end portion 85 and the upper end portion 82 are tapered.

The above-mentioned five steps of molding are carried out by an ordinary multi-stage horizontal press machine to obtain a molded body 80 having an annular recess 84 formed on the inner periphery thereof.

Next, the formed body 80 is subjected to a normal tapping process to form a female thread having a pitch P1 (see FIG. 10). However, the female screw 93 is partially missing at the recess 91. However, ignoring the missing points, the pitch of the screw portion straddling the recess 91 is the same value P1 as the pitch of the other portions.

Finally, the molded body 90 is pressed in the direction of arrow A, that is, in the axial direction, and the pitch of the screw portion straddling the recess is set to P1.
To P2 to obtain the nut 10 shown in FIG. Here, the pitch of the screw portion straddling the recess is defined by ignoring the discontinuity of the screw thread as described above, and the distance between the crests 14 and 15 of the screw threads on both sides of the recess 11 or It means the distance between the valley bottoms 16 and 17 on both sides of the recess 11. The press also reduces the width of the recess. The desirable dimensions (ratio) of each part of the nut are as described above.

[0035]

EFFECTS OF THE INVENTION The loosening prevention nut of the present invention is provided with annular recesses 11 and 21 on the inner circumference of the nut, and screw crests 14, 15; 24 and 25 located on both sides of the recesses 11 and 21. Of the valley bottom 1 located on both sides of the interval P2 or the recesses 11 and 21
6, 17; 26, 27 is the pitch of the other threaded portion P1
Since it is shorter than the above, the following effects can be obtained. a) Since the screw thread itself can be formed in a normal size and with a mountain shape by a normal method, it is possible to reduce variations in quality.
A stable loosening prevention effect can be obtained. b) The height of the nut can be set equal to or lower than that of the conventional product. c) It can be used at higher temperatures than conventional products that use resins and adhesives. d) The number of man-hours for assembling the nut is equal to the minimum man-hour for the conventional loosening prevention nut. e) The loosening prevention effect is substantially independent of the condition of the tightened body.

Further, in the method for manufacturing the loosening prevention nut of the present invention, tapping processing is performed on the molded body 80 having the annular recess 84 on the inner periphery to form a predetermined pitch P1 on the inner periphery of the molded body 80.
Forming the female screw 93, and pressing the molded body 90 on which the female screw 93 is formed in the axial direction to reduce the interval between the recesses 91, and to make the crests 14 and 15 of the screw threads located on both sides of the recess 11 respectively.
Or the interval between the valley bottoms located on both sides of the recess 11 is shorter than the pitch P1 of the other threaded portion, so that a high-precision loosening prevention nut can be easily manufactured at low cost. it can.

The present invention is not limited to the above embodiment. For example, the recess provided on the inner circumference may be arranged near the center instead of near one end of the nut. In that case, the pitch of each continuous threaded portion on both sides of the recess may be the same or different. In that case, the pitch of the discontinuous threaded portion straddling the recess is set to a value smaller than any pitch of the continuous threaded portions on both sides. Further, the shape of the recess is not limited to the above-mentioned embodiment, and may be another shape. For example, the thickness of the recess may not be uniform and the bottom may be wide.

[Brief description of drawings]

FIG. 1 is a view showing an embodiment of a loosening prevention nut of the present invention.

FIG. 2 is a partially enlarged view of FIG.

FIG. 3 is a view showing another embodiment of the loosening prevention nut of the present invention.

FIG. 4 is a view for explaining the method for manufacturing the loosening prevention nut of the present invention.

FIG. 5 is a view for explaining the method for manufacturing the loosening prevention nut of the present invention.

FIG. 6 is a view for explaining the method for manufacturing the loosening prevention nut of the present invention.

FIG. 7 is a view for explaining the method for manufacturing the loosening prevention nut of the present invention.

FIG. 8 is a view for explaining the method for manufacturing the loosening prevention nut of the present invention.

FIG. 9 is a view for explaining the method for manufacturing the loosening prevention nut of the present invention.

FIG. 10 is a view for explaining the method for manufacturing the loosening prevention nut of the present invention.

FIG. 11 is a view for explaining the method for manufacturing the loosening prevention nut of the present invention.

[Explanation of symbols]

 10,20 Loosening prevention nut 11,21,84,91 Recess 12,22 Seat surface 13,23 Screw thread 14,15,24,25 Peak of peak 16,17,26,27 Valley bottom 28 Flange 30 Material 40,50 , 60, 70, 80 Molded body 90 Nut 93 Female thread

Claims (2)

[Claims] 1. An annular recess (11, 2) on the inner circumference of the nut.
1) is provided and is located on both sides of the recess (11, 21) or the interval (P2) of the screw crests (14, 15; 24, 25) located on both sides of the recess (11, 21). Valley bottom (16,
17; 26, 27) is the pitch of the other screw parts (P
A loosening prevention nut characterized by being shorter than 1). 2. A method for manufacturing a loosening prevention nut, wherein a molded body (80) having an annular recess (84) on its inner circumference is subjected to tapping to form a predetermined pitch () on the inner circumference of the molded body (80). P1) forming the female screw (93), and pressing the molded body (90) formed with the female screw (93) in the axial direction to reduce the interval between the recesses (91), and the both sides of the recess (11). Spacing or recess (1) of the crests (14, 15) of the thread located at
1) A method for manufacturing a loosening prevention nut, characterized by including a step of making an interval between valley bottoms located on both sides adjacent to each other shorter than a pitch (P1) of another threaded portion.