JPH09273531A - Locking nut - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a locking nut which can accurately set frictional resistance for locking. SOLUTION: A female screw 13 of a nut body 11 has a truly octagonal hole at its center. An intermediate portion of each side 12a of the hole 12 is located on a center side compared to a thread root diameter D of a screw thread 22 of a male screw 21. When the female screw 13 of the nut body 11 is screwed with the male screw 21, the side 12a of the hole 12 bites into the male screw 21 to provide frictional resistance for locking.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lock nut having a lock function.

[0002]

2. Description of the Related Art Conventionally, for example, in a tightening structure using a bolt and a nut, in order to prevent the nut tightened on the bolt from loosening or falling off, after the regular nut is completed, the nut is cut from the outer peripheral portion of the nut. A part of the female screw is deformed by applying plastic working, and by this deformation,
When the nut is screwed into the bolt, it provides frictional resistance to prevent loosening.

[0003]

Generally, in order to mass-produce nuts, an intermediate product having a circular pilot hole in the center is formed by a forging machine, and then a female screw is formed in the pilot hole of the intermediate product. It is manufactured by engraving.

However, when the above intermediate product is formed by forging, variations occur in the height of the nut, that is, the length of the nut in the direction of driving the punch into the die. Therefore, when the regular nut is completed, plastic deformation is applied from the outer periphery of the regular nut to deform a part of the female screw, and when the deformation tries to give friction resistance to prevent loosening, the degree of deformation is kept constant. It was very difficult to do so, and it was not possible to always set the frictional resistance to prevent loosening with high precision. In particular, if the amount of deformation is too large, there is a problem that seizure occurs when tightening the nut on the bolt.

Therefore, the present invention has been made to solve the above problems, and an object of the present invention is to provide a locking nut which can always set the friction resistance for locking to be accurate.

[0006]

Means for Solving the Problems In order to achieve the above object, the present invention is characterized in that it is configured as follows.

That is, in the invention according to claim 1 of the present application (hereinafter referred to as the first invention), the hole shape of the central portion of the female screw in the nut body is polygonal, and the intermediate portion of each side of the hole is the above-mentioned. It is characterized in that it is formed so as to be located closer to the center side than the root diameter of the screw thread in a regular male screw that is screwed into the female screw.

The invention according to claim 2 (hereinafter, referred to as a second invention) is such that the center of the thread ridge of the regular male screw threaded with the female thread is located at the top of the thread ridge of the female thread in the nut body. It is characterized in that an outwardly bulging arcuate bulging portion bulging outward is provided intermittently.

According to the above construction, the following effects can be obtained.

First, according to the first aspect of the invention, the intermediate portion of each side of the polygonal hole in the female screw is formed so as to be located closer to the center side than the root diameter of the screw thread in the regular male screw screwed with the female screw. Therefore, when this nut body is screwed into, for example, a male screw of a bolt, the intermediate portion of each side of the polygon interferes with the valley portion of the thread of the male screw and bites into the valley portion. As a result, it becomes possible to accurately give a frictional resistance for preventing loosening.

According to the second aspect of the invention, the outer bulging arcuate bulging portion bulging toward the center side of the root diameter of the thread of the regular male thread is intermittently connected to the top of the thread of the female thread of the nut body. Since this nut body is screwed into a male screw of a bolt, for example, each of the bulged portions interferes with the valley portion of the thread in the male screw and bites into the valley portion. This makes it possible to accurately give a frictional resistance for preventing loosening.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

First, FIGS. 1 to 6 show an embodiment of the first invention in the present invention.
As shown in FIGS. 1 and 2, there is a regular octagonal hole 12 in a plan view at the center of a nut body 11 having a hexagonal outer periphery, and the regular octagonal hole 12 has a regular octagonal hole 12 such as a bolt 2. A female screw 13 that is screwed into the male screw 21 is formed.

As shown in FIGS. 1 and 2, the dimension H between the opposite sides 12a, 12a of the regular octagonal hole 12 is formed to be smaller than the root diameter D of the screw thread 22 in the male screw 21 of the bolt 2. ing. Further, a disc-shaped brim portion 14 is integrally provided at one axial end portion of the nut body 11. Further, in FIG. 3, reference numerals 12b ... 12b are corner portions of the regular octagonal hole 12, and reference numeral O is the internal thread 1
It is the center of 3.

In the nut 1, first, a nut body 11 having a regular octagonal pilot hole in the center is formed by a forging machine, and then the pilot hole of the nut body 11 is tapped (not shown). It is manufactured by performing thread cutting and engraving the internal thread 13. Here, in the thread cutting process, a tap having a blade shape in which the middle portion of each side 12a of the regular octagonal hole 12 is left as it is without being cut is used.

According to the above structure, the dimension H between the opposite sides 12a, 12a of the regular octagonal hole 12 in the nut body 11 is increased.
Is formed to be smaller than the root diameter D of the screw thread 22 in the male screw 21, when the nut body 10 is screwed into the bolt 2, the opposite sides of the regular octagonal hole 12 as shown in FIGS. 2 and 6. The intermediate portions of 12a ... 12a interfere with the troughs 23 of the thread ridges 22 of the male screw 21 and bite into the troughs by a certain amount, whereby friction resistance for preventing loosening can be accurately provided. It will be possible.

In that case, each side 12a of the regular octagonal hole 12 ...
The intermediate portions of 12a can be made to bite into the valleys 23 of the threads 22 of the male screw 21 of the bolt 2 at a certain depth with a certain angle respectively, so that the friction resistance for preventing loosening can be increased. It is possible to always set with high accuracy.

According to the embodiment described above, the hole 12
Although the shape of is a regular octagon, it may be a regular polygon other than a regular octagon or a polygon. Of course, the regular polygon or the corner of the polygon may be rounded. Furthermore, by selecting the size of the regular octagonal hole 12, it becomes possible to arbitrarily change the setting of the friction resistance for preventing loosening.

Next, FIGS. 7 to 9 show an embodiment of the second invention, in which the locking nut 3 has a hexagonal outer periphery at the center of a nut body 31 and a regular male screw of a bolt 4. It has an internal thread 32 screwed to 41.

At the top of the thread 33 of the female thread 32, an outwardly bulging arcuate bulge 34 ... 3 bulging toward the center side of the root diameter D of the thread 42 of the regular male thread 41.
Many 4 are intermittently provided with an angle difference of 90 degrees so that four 4 appear in a plan view. Further, a disc-shaped brim portion 35 is integrally provided at one axial end portion of the nut body 31. In FIG. 9, the symbol O is the center of the female screw 32.

The nut 3 is first formed by a forging machine to form a flanged nut body 31 having a circular pilot hole in which four bulged portions are left in the center, and then the nut body 31 is formed. It is manufactured by subjecting the prepared hole to threading with a tap (not shown) and engraving the female screw 32 having the bulged portions 34 ... Here, in the thread cutting process, a tap having a blade shape in which the outer bulging arcuate bulging portion 34 remains as it is without being cut is used.

According to the above-mentioned structure, the outer bulge arcuate bulge which bulges toward the center side from the root diameter D of the thread ridge 42 of the regular male thread 41 on the top of the thread 33 of the female thread 32 of the nut body 31. 34 are provided intermittently, so that when the nut body 31 is screwed into the male screw 41 of the bolt 4, for example, the bulged portions 34 are formed.
The intermediate portion of 34 interferes with the trough portion 43 of the thread 42 of the male screw 41 and bites into the trough portion 43,
This makes it possible to accurately give a frictional resistance for preventing loosening.

In this case, the intermediate portions of the respective bulging portions 34 ... 34 are bited into the trough portions 43 of the threads 42 of the male screw 41 of the bolt 4 with a certain depth and at a certain depth. Therefore, it is possible to always set the frictional resistance for preventing loosening with high accuracy.

According to the above-mentioned embodiment, the number of the bulging portions 34 when the nut body 31 is viewed from the plane is four, but this number is not limited at all and is two.
It is sufficient that the number is three or more, and it is preferable that the phase angles are equally divided. Further, by selecting the size of the bulging portion 34, it is possible to arbitrarily change the setting of the friction resistance for preventing loosening.

[0025]

As described above, according to the first invention of the present application, the hole shape of the central portion of the female screw in the nut body is polygonal, and the intermediate portion of each side of the polygonal hole is the female screw. Since this nut is formed so as to be located closer to the center side than the root diameter of the thread in the regular male screw to be screwed, when this nut is screwed into the male screw of a bolt, for example, the middle portion of each side of the polygon Interferes with the valley of the thread on the male screw, and it is possible to cut into that valley,
As a result, it becomes possible to always set the frictional resistance for preventing loosening with high accuracy.

Further, according to the second aspect of the invention, the outer bulging arcuate bulging portion bulging toward the center side of the root diameter of the thread of the regular male thread is intermittently connected to the top of the thread of the female thread of the nut body. However, when the nut body is screwed into a male thread of a bolt, the bulged portions interfere with the valleys of the threads of the male thread and bite into the valleys. Therefore, it becomes possible to always set the frictional resistance for preventing the looseness with high accuracy. Further, since the bulging portion has an outwardly bulging arcuate shape, when the bulging portion bites into the valley portion, the bulging portion can bite relatively smoothly, and deformation of the bulging portion can be suppressed.

[Brief description of drawings]

FIG. 1 is a plan view of a locking nut according to the present invention.

FIG. 2 is a front view of the same.

FIG. 3 is a partially enlarged cross-sectional view of the same main part.

FIG. 4 is an enlarged cross-sectional view taken along the line AA of FIG.

5 is an enlarged cross-sectional view taken along line BB of FIG.

FIG. 6 is a vertical cross-sectional view showing a state in which a locking nut is screwed into a bolt.

FIG. 7 is a plan view of a lock nut according to another embodiment of the present invention.

FIG. 8 is a front view of the same.

FIG. 9 is a partially enlarged transverse sectional view of the same main part.

[Explanation of symbols]

 1,3 Loosening preventive nut 11,31 Nut body 11 Female screw 12 Hole 12a Opposite side 32 Female screw 33 Thread ridge 34 Swelling part

Claims (2)

[Claims] 1. The hole shape of the central portion of the female thread in the nut body is polygonal, and the middle portion of each side of the hole is closer to the center side than the root diameter of the screw thread in the regular male screw screwed with the female thread. A locking nut, which is characterized in that it is formed so as to be located at. 2. An outwardly bulging arcuate bulging portion bulging toward the center side from the root diameter of the thread of a regular male thread screwed with the female thread is intermittently provided at the top of the thread ridge of the female thread in the nut body. Locking nut that is provided on the.