JPH0775750B2 - Nut manufacturing method - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates to relates <br/> the manufacture how the nuts.

[0002]

2. Description of the Related Art Conventionally, the following methods have been known as a method for manufacturing nuts using a hexagonal steel pipe. (1) The ratio of the opposite side thickness of the nut to the opposite side length is large,
For long nuts, there is a method in which a hollow hexagonal steel pipe is cut out from a solid round steel bar and screwed.
There is also a method of manufacturing from a hexagonal steel tube obtained by carving the inside of a hexagonal steel bar manufactured by rolling or the like. (2) For nuts having a relatively short length, there is a method of manufacturing a material for nuts by forging. (3) Other For manufacturing a hexagonal steel pipe having a small ratio of opposite side thickness to opposite side length, there is a method of subjecting a round steel pipe to cold core drawing.

[0003]

Since the above method (1) is a method of cutting out from a steel bar, there are problems that the yield loss is large and the tool unit is poor. Further, if the length of the nut becomes long, the inside is cut out from both end surfaces of the steel bar, but since the alignment of the cut-out tips of both ends is difficult, there is a problem that the step difference occurs in the center part. . Furthermore, since this method is inefficient, a drastic improvement measure is desired due to the lack of manpower these days. Since the method of (2) is forging, it is inefficient, and in order to use it as a nut material, the inner surface after forging is cut,
There is a problem that a process such as finishing is required. Also, there is a drawback that long products cannot be manufactured. The method (3) is based on cold centering, but it was originally intended for those with a small ratio of the opposite side thickness of the hexagon to the opposite side length, and the inner shape as well as the outer shape was hexagonal. Also, as can be seen from the fact that the material before cold-coring is an electric resistance welded pipe, it is intended to produce thin-walled hexagonal steel pipes exclusively, not to produce screws. The present invention, product yield, working efficiency, better tools intensity, and an object thereof is to provide a manufacturing how opposite sides portion thickness and opposite side portions Nuts can respond to what the length of the ratio large hexagonal steel .

[0004]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above-mentioned object, and produces a round steel pipe,
Hexagonal die and round cored bar are used as the steel pipe
Outer diameter D of the raw pipe = diagonal length of hexagonal steel pipe W × (1.0
5 to 1.33), cross-section reduction rate Re = 1- (cross-sectional area of hexagonal steel pipe) / (cross-sectional area of round steel pipe that is a raw pipe) = 0.30
Performing cold Shin引machining than conditions of the ～0.48 form a hexagonal steel pipe, which is a feature and be Luna <br/> Tsu preparative such manufacturing method of the applying directly threaded. A seamless steel pipe is usually used as a raw pipe for producing the hexagonal steel pipe of the present invention. This is because the seamless steel pipe has excellent strength and is suitable for producing a thick material as a raw pipe. The core tube is cold cored using a hexagonal die and a round cored bar. In that case, the following conditions are preferable. The outer diameter D of the raw pipe immediately before working is D = the length of the diagonal part of the hexagonal steel pipe W × (1.05 to 1.33). Here, the reason for being 1.05 is that if it is smaller than this, the filling degree of the meat of the corner portion, which is important as a hexagonal steel pipe used as a material for screws, becomes insufficient. Also,
The reason for 1.33 is that if it is larger than this, there is a risk of material breakage during core processing, chattering of processing, and seizure. Further, as the next condition, the cross-section reduction rate Re = 1- (cross-sectional area of hexagonal steel pipe) / (cross-sectional area of round steel pipe which is a raw pipe) = 0.30 to 0.48. Here, 0.30 means that if it is smaller than this, the filling degree of the meat of the corner portion of the hexagonal steel pipe becomes insufficient, and the cored hexagonal steel pipe is not processed at all, and nuts themselves are used. This is because it cannot be used as a thread-cutting material for the like. The reason why it is 0.48 is that if it is larger than this, there is a risk of material breakage during core drawing. The nuts referred to in the present invention refer to a tightening nut, a mouthpiece of a rubber hose, a screwing nut, a nipple, and the like. As these nuts, those having a ratio of the thickness T of the opposite side portion and the length B of the opposite side portion of the hexagonal steel pipe of 0.15 or more are used. Further, this ratio is usually 0.37 or less. Since the cold-cored hexagonal steel pipe has a finished surface as a material for screws, the inner surface or the outer surface can be directly threaded.

[0005]

Embodiments of the present invention will be described with reference to the drawings.
In FIG. 1, a hexagonal die 1 of a cold centering machine and a round metal core 2 attached to a support bar 5 are used to perform a centering process using a round steel pipe 3 as a raw material to form a hexagonal steel pipe 4. Figure 2
(A) shows a hexagonal steel pipe 4, and FIG. 2 (b) shows a dimensional display of each part of each round steel pipe. In this example, a hexagonal steel pipe A shown in Table 2 was core-processed by using the cold core forming machine shown in FIG. Similarly, hexagonal steel pipes B to I were manufactured from the round base pipes B to I. The hexagonal steel pipe as it is subjected to a threaded, to produce a coupler, corners
It was possible to obtain a good product having excellent filling rate with good yield. The yield was improved by 30% as compared with the case of cutting a conventional solid steel bar, and a long nut that could not be produced by the conventional forging could be produced. Further, since the surface finishing processing such as peeling, which is conventionally performed, is not required, the processing step can be omitted.

[0006]

[Table 1]

[0007]

[Table 2]

[0008]

Since the present invention is configured as described above, it is possible to thread a cold-cored hexagonal steel pipe as it is, to produce high-quality screws with good yield and long length. it can. In addition, it is possible to improve the production efficiency and reduce the tool unit consumption. Hexagonal steel produced by the manufacturing method of the present invention
The tube has a good filling of the meat at the corners, and the surface such as peeling
Screwing for nuts without the need for finishing
It can be used for craft materials.

[Brief description of drawings]

FIG. 1 is a diagram showing an aspect of cold core drawing a hexagonal steel pipe into a round pipe, which is a round steel pipe according to the present invention.

FIG. 2 is a diagram showing a dimensional relationship between a base pipe and a hexagonal steel pipe.

[Explanation of symbols]

 1 Die 2 Core 3 Round steel pipe 4 Hexagonal steel pipe 5 Support bar

Claims (1)

[Claims] 1. An outer diameter D of a raw pipe manufactured by manufacturing a round steel pipe, using the steel pipe as a raw pipe and using a hexagonal die and a round cored bar.
= Diagonal length W of hexagonal steel pipe x (1.05 to 1.33),
Cross-section reduction rate Re = 1- (cross-sectional area of hexagonal steel pipe) / (in raw pipe
Cross-sectional area of a certain round steel pipe) = 0.30 to 0.48
A method for manufacturing nuts, which comprises cold-coring to form a hexagonal steel pipe, and then directly threading.