JPS61278613A - Box nut made of sheet metal - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a bag nut made by pressing a plate material.

[Conventional technology]

Conventionally, in order to improve the productivity of nut manufacturing, it has been considered to manufacture nuts by plastic working from plate materials (
For example, Japanese Patent Application Laid-open No. 18612/1983).

However, when applying this technology to a cap nut, since the screw hole formed in the nut material is a blind hole,
It cannot be passed through taps or rolling dies like in the past,
It was not possible to improve productivity. In addition, like a tool for blind holes, a predetermined thread is formed near the tip so that a thread can be effectively formed even in the deepest part of the pilot hole, and the guide part at the tip is extremely short. When using a tool, a large machining force is required for machining, which accelerates tool wear.

[Purpose and structure of the invention]

2 This invention aims to eliminate the above-mentioned problems and obtain a cap nut with excellent productivity.The invention has a flange formed by drawing a plate material, and an outer surface that protrudes to one side from the flange. In a device that integrally has a square bottomed tubular protrusion and a female thread is carved on the inner surface of the tubular protrusion, a shaft having a diameter larger than the thread diameter of the female thread is provided on the inner surface of the tubular protrusion. It is characterized by the formation of concave grooves in different directions.

〔Example〕

Hereinafter, this invention will be explained with reference to the illustrated embodiments. A plate material with excellent ductility is drawn and integrally has a flange portion 2 and a tubular protrusion 3 projecting to one side from the flange portion 2. FIG. 6 shows an example of using the cap nut 1 according to the present invention, in which the cap nut I is screwed onto the upper end of a stud bolt B that has passed through an article A with a seal washer W interposed therebetween.

The tubular protrusion 3 of the cap nut 1 is bulged from the flange portion 2 by drawing, and the outer surface is precisely finished through a restriking process.The outer surface has a substantially regular hexagonal engagement surface for a spanner or other tool. 3a is formed, and a cap body 3b is formed at the end.
The bottom of a circular screw hole H forming a shape is integrally provided.

In this drawing and shaping process, it is not easy to change the thickness of the base material too much in terms of the life of the mold, so the top of the hexagon that protrudes to the outside does not have an acute angle, but has a radius. Although it forms a small arc, on the back side of the hexagonal top that bulges outward, six axial grooves 4 are formed corresponding to the top, and the screw hole H on the inside is correct. It will not be circular. To explain the state in which a thread is carved in this figure, S indicates the top diameter of the female thread or the bottom diameter of the male thread, and m indicates the bottom diameter of the female thread or the top diameter of the male thread.

Here, the six grooves 4 are arranged at equal intervals around the pilot hole H of the screw, and a virtual circle (not shown) connecting their bottom surfaces is concentric with the pilot hole H. Its diameter is the thread diameter of the female thread 3
It is formed with a larger diameter.

That is, in the It/-IV cross section at the engagement surface 3a of the tool, as shown in FIG. 4 or FIG. 8, the inner diameter of the pilot hole H,
The diameter of the hole is approximately the same as the thread diameter 3 of the female thread, and there is no difference from the conventional pilot hole, but in the V-■ section at the top of the hexagon, due to the presence of the groove 4, the pilot hole H is the bottom surface of the groove 4. Since it has expanded to the position of , the dimension is close to the valley Jim of the female thread. Therefore, there are no ridges for the set screws shown in the drawing in this part, but details regarding this point will be described later.

Since the cap nut 1 has the above structure, if the plate thickness is appropriately selected, a female threaded pilot hole H having six grooves 4 deeper than the thread diameter S of the female thread can be formed on the inner surface of the tubular protrusion 3. It is formed. Therefore, when inserting a bolt-shaped rolling die or tap into the prepared hole to form a threaded thread, the material moved by rolling fills the groove 4 or is cut by the tap. Since the chips escape into the groove 4, the machining force acting on the tool is reduced, and even if a blind hole tap with a short guide section is used, the load is relatively light, increasing durability and improving productivity. becomes possible.

Note that the shape of the bag nut 1 is not limited to the one described above.
As shown in FIGS. 7 and 8, the upper surface 2 of the flange portion 2
A can also be made into a loose conical surface with a thin edge, thereby making it possible to further reduce the weight of the cap nut. At the same time, by providing a conical relief on the lower surface 2b and forming only the peripheral edge 2c as a seating surface and the vicinity of the screw hole formed into a conical shape, elasticity is generated in the flange portion 2, and the tightening of the cap nut 1 is sometimes performed using a washer. It is also possible to make it unnecessary.

〔Effect of the invention〕

As described above, the present invention integrally includes a flange formed by drawing a plate material and a bottomed tubular protrusion whose outer surface is a regular polygon and which protrudes from the flange. In the case where a female thread is carved on the inner surface of the tubular protrusion, an axial concave groove with a diameter larger than the root diameter of the female thread is formed on the inner surface of the tubular protrusion. It is easy to move the material, and tapping makes it easy to remove chips, making it easy to form female threads, extending tool life, and improving productivity. play.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is an external view of a cap nut, Fig. 2 is a plan view thereof, Fig. 3 is a bottom view thereof, and Fig. 4 is a mV- mV cross section, Figure 5 shows V
-V sectional view, FIG. 6 is a sectional view showing a state of use, and FIGS. 7 and 8 are views corresponding to FIGS. 1 and 4 showing other embodiments. 1 - bag nut, 2... flange part, 3...
-・Tubular protrusion, 3a--Tool engagement surface, 3b-・
-Cap body, 4-Concave groove, Patent applicant: Tokiwa Industries Co., Ltd. $4. @ calculation g prisoner a hole ot concave calculation 5 figure

Claims (3)

[Claims] (1) It integrally has a flange formed by drawing a plate material and a bottomed tubular protrusion whose outer surface is a regular polygon and which protrudes to one side from the flange, and the inner surface of the tubular protrusion is A sheet metal bag nut in which a thread is carved, wherein an axial concave groove having a diameter larger than the thread diameter of the female thread is formed on the inner surface of the tubular protrusion. (2) The groove having a diameter larger than the root diameter of the female thread is formed on the inner surface of the corner formed on the outer surface.
Sheet metal bag nut as described in section. (3) The sheet metal bag nut according to claim 1, wherein the plate material is a soft metal having good corrosion resistance in the atmosphere, such as an aluminum alloy or a copper alloy.