JP3517783B2 - Manufacturing method of hollow shaft parts - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a hollow shaft part, and more particularly to a method for manufacturing a hollow shaft part in which a head is integrally formed from a pipe material at one end of the hollow shaft part.

[0002]

2. Description of the Related Art Conventionally, for example, a hollow bolt is manufactured from a pipe material in order to reduce the weight. In that case, as a method of manufacturing the hollow bolt, the outer diameter is approximately the same as the outer diameter of the hollow shaft portion 11 'of the hollow bolt 1'as shown in FIG. 14 is used as the material A ', and a pipe material having a length substantially the same as the entire length of the hollow bolt 1'is used as the material A'. As shown in FIG. 1, a first material B'formed by expanding a head portion B2 'having a thickness smaller than that of the hollow shaft portion B1' is formed at one end portion of the hollow shaft portion B1 '. In the second step, the head B2 'of the first material B1' is driven into a work piece,
As shown in FIGS. 15 and 16, the hollow shaft portion 11 ′ and the head portion 1
The boundary portion with 2'buckles outward in the radial direction, and the collar-shaped seat portion 1
At the same time as forming 5 ', the wall thickness of the head portion 12' is increased, and a hollow bolt 1'with a collar is formed in which the outer periphery of the head portion 12 'is formed into a hexagonal cross section. . The hollow shaft portion 1 of the hollow bolt 1'shown in FIG.
At the tip of 1 ', a reduced diameter tip 16' is formed in which a thread groove is formed in a later step.

[0003]

However, in the above-described manufacturing method, the wall thickness of the boundary portion between the hollow shaft portion 11 'and the head portion 12' is the head portion when expanding the pipe in the first step. Together with 12 ', it becomes thinner than the wall thickness of the hollow shaft portion 11'. Moreover, since the boundary portion is buckled outward in the radial direction to form the collar-shaped seat portion 15 ', the structure shown in FIG.
The collar-shaped seat portion 15 'of the hollow bolt 1'molded as shown in FIGS. 5 and 16 has a crack 17' at its intermediate portion in the wall thickness direction. Due to the compressive force during bending, the wall thickness on both sides of the crack 17 'is further reduced. As a result, the strength of the connecting portion between the collar-shaped seat portion 15 'and the hollow shaft portion 11', the so-called neck portion 14 ', is significantly reduced compared to other portions, and when fastening using this hollow bolt 1', There is a problem that the neck portion 14 'is inadvertently broken.

Therefore, according to the present invention, the hollow shaft part can be manufactured from a pipe material to reduce the weight thereof, and at the same time, the strength of the so-called neck part where the head part and the hollow shaft part are connected can be prevented from being lowered. An object is to provide a method of manufacturing a part.

[0005]

In order to solve the above problems, the invention of claim 1 of the present application manufactures a hollow shaft part in which a head is integrally formed from one end of the hollow shaft part from a pipe material. As a method, a pipe material having a diameter larger than the outer diameter of the hollow shaft portion of the shaft part and having a thicker wall and a length shorter than the shaft part is used as a raw material. First, in the first step, this raw material is diced from one direction. To form a first material having a thick head portion at one end and a hollow shaft portion having a smaller diameter and thinner than the above material at the other end, and then in the second step, the first material is formed. and upsetting <br/> processed head portion while push the head in forming pins of the material, as well as bulge forming into a predetermined shape mouth portion of the head, between the head and the hollow shaft portion Buckling the boundary part in the radial direction
It is characterized in that the thickness of the head portion and the thickness of the connecting portion between the head portion and the hollow shaft portion are formed to be larger than the thickness of the hollow shaft portion without being performed.

The invention of claim 2 of the present application, in addition to the invention of claim 1 described above, further comprises a second material formed in the second step.
In the third step , the outer peripheral portion of the head is cut along the entire length of the head to form a head having a predetermined cross-sectional shape.

Furthermore, the invention of claim 3, in addition to the first aspect of the present invention described above, in the second material formed in the second step third step, the hollow shaft portion outer peripheral portion at the head portion It is characterized in that a head having a predetermined cross-sectional shape is formed by cutting and upsetting to a close position, and a collar-shaped seat portion is bulged between the head portion and the hollow shaft portion.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. The drawings show an embodiment in the case where a hollow bolt 1 having a collar-shaped seat portion 15 and a head portion 12 at one end of a hollow shaft portion 11 is manufactured from a pipe material in order to reduce the weight. Indicates.

2 to 8 show changes in shape in the molding process when the hollow bolt 1 is manufactured from a pipe material by a multi-stage press forming machine. As shown in FIG. 3, when using a pipe material as a raw material, the outer diameter is larger than the outer diameter of the hollow shaft portion 2 of the hollow bolt 1 required, and the wall thickness is larger than the wall thickness of the hollow shaft portion 2. , Further length hollow bolt 1
A cutting material A that is shorter than the above is used.

First, in the first step, the material A is pressed into a die (not shown) from one direction and drawn. As a result, as shown in FIG. 4, a hollow shaft portion B1 having a diameter smaller than the outer diameter of the material A and having a thin wall and an extended length, and a thick head portion at one end of the hollow shaft portion B1. A first material (primary molded product) B having B2 is formed.

[0011] Next, in the second step, Push the forming pins of the cross-section hexagonal head B2 of the first material B (not shown) all
Processing carried out upsetting the reluctant head portion. As a result, FIG.
As shown in FIG. 6, the mouth portion C3 of the head portion C2 is expanded into a hexagonal shape, and at the same time, between the head portion C2 and the hollow shaft portion C1.
The wall thickness of the head portion C2 and the wall thickness of the connecting portion (hereinafter referred to as the neck portion) C4 between the hollow shaft portion C1 and the head portion C2 are larger than the wall thickness of the hollow shaft portion C1 without the boundary portion buckling in the radial direction. The second material (secondary molded product) C formed so as to be formed is formed. The lower surface of the head C2 is formed vertically so as to become the seat C5.

[0012] Thereafter, in the third step, to near the hollow shaft portion C1 so as to die-cut outer peripheral portion hexagonal in the head C2 of the second material C, upsetting and cut to the neck portion C4 near other words Along with processing, hollow shaft C1
The other end of is drawn in a die (not shown). As a result, as shown in FIGS. 7 and 8, a head portion D2 having a hexagonal cross section is formed, and at the same time, a collar-shaped seat portion D5 is formed between the head portion D2 and the hollow shaft portion D1. At the other end of the hollow shaft portion C1, a reduced diameter tip portion D6 in which a thread groove is formed in a later step is formed. That is, a third material (third-order material) in which the collar-shaped seat portion D5 and the hexagonal head portion D2 having the hexagonal mouth portion D3 are integrally formed at one end of the hollow shaft portion D1 and the reduced diameter tip portion D6 is formed at the other end A molded product) D is formed.

After that, in the fourth step, the outer peripheral portion of the collar portion D5 of the third material D is punched into a circular shape, and the hollow shaft portion D1 and the reduced diameter tip portion D6 are dimensioned. I do. As a result, as shown in FIGS. 1 and 2, the collar-shaped seat portion 15 and the hexagonal head portion 12 having the hexagonal mouth portion 13 are integrally formed at one end of the hollow shaft portion 11, and the reduced diameter tip portion is provided at the other end. A hollow bolt 1 having 16 is formed.

When forming the reduced-diameter tip portion 16 by drawing the tip portions of the hollow shaft portions C1 and D1, a forming pin penetrating the head portion, the seat portion and the hollow shaft portion is used on the punch side. It is preferable to carry out. Further, on the outer periphery of the reduced diameter tip portion 16,
Although not shown, a thread groove is formed by thread rolling or cutting in a later step.

As described above, when the hollow bolt with a collar is manufactured by the manufacturing method of the present invention, the collar-shaped seat portion 15 and the head portion 12 are provided at one end of the hollow shaft portion 11 from the cutting material A made of a pipe material. The hollow bolt 1 having the hollow shaft 1 can be manufactured, and the weight can be reduced. Further, the wall thickness of the head 12 and the wall thickness of the neck portion 14 of the collar-shaped seat portion 15 and the hollow shaft portion 11 are set to the hollow shaft portion 1.
The thickness of the head 1 is larger than that of the head 1, and the neck 14 is not cracked as in the conventional case.
2 and the strength of the neck portion 14 can be increased more positively than the strength of the hollow shaft portion 11. Accordingly, when the object to be fastened is fastened using the hollow bolt 1, the neck portion 14
It is possible to prevent accidental breakage.

In addition, in the third step, the second material is cut and upset at the outer peripheral portion of the head portion C1 to near the hollow shaft portion C1 to form the head portion D2 having a predetermined shape. Since the collar-shaped seat portion D5 is formed to bulge between the head portion D2 and the hollow shaft portion D1, the meat of the head portion D2
Forming the head D2 and forming the collar-shaped seat portion D5 while maintaining the thickness and the thickness of the neck portion D4 between the head portion D2 and the hollow shaft portion D1 larger than the thickness of the hollow shaft portion D1. It can be carried out. Thus, without breaking prevention effect of the neck 14 is impaired, while it is possible to form the head D2 into hexagonal shape, it is possible to increase the area of the seat portion D5 by flanged seat D5 .

In the above-described embodiment, a hollow bolt 11 is formed as a hollow bolt at the tip of the hollow shaft portion 11 so as to form a thread groove.
Although the diameter-reduced tip portion 16 may not be formed as necessary, the inner surface of the tip portion of the hollow shaft portion 11 may be formed with an internal thread.
Furthermore, it goes without saying that the length and diameter of the hollow shaft portion 11 can be set arbitrarily.

Further, although the hollow bolt 1 has been described in the above-mentioned embodiment, the hollow bolt 1 is not limited to the bolt at all, and, for example, a hollow bolt 1 formed only up to the second step as shown in FIG. A hollow shaft part that does not form a screw that has a head at one end of the shaft part,
Alternatively, it may be a hollow shaft part that is formed by the third step or the fourth step as shown in FIG.

Further, as shown in FIGS. 9 and 10, in the third step, the outer peripheral portion of the head is cut along the entire length of the head to form a head having a predetermined shape without a flange-shaped protrusion. It may be a hollow bolt 2 or a hollow shaft part.

Further, in the hollow bolt or hollow shaft part, the shape of the head and the shape of the mouth are not limited to hexagons, but may be circular or polygonal, as well as a gear as shown in FIG. It may have a shape or an irregular shape as shown in FIG.

[0021]

As described above, according to the manufacturing method of the present invention, it is possible to manufacture a hollow shaft part having a head portion at one end of the hollow shaft portion from a cutting material made of a pipe material, and it is possible to reduce the weight, Moreover, the boundary between the head and the hollow shaft is
Connecting portion between the thick and the head portion and the hollow shaft portion of the head without buckling in the radial direction, that Ru can be formed larger than the wall thickness of the hollow shaft portion the wall thickness of the neck portion. Therefore, as in the past
The neck portion is not cracked, and the strength of the head portion and the neck portion can be prevented from being lower than the strength of the hollow shaft portion. Therefore, when using this hollow shaft part,
It is possible to prevent accidental breakage from the neck portion.

Further, the second material formed in the second step is used as a third material.
In the step, by cutting the outer peripheral portion of the head over the entire length of the head so as to form a head having a predetermined cross-sectional shape, the wall thickness of the head and the hollow shaft portion It is possible to maintain the state where the wall thickness of the connecting portion is made larger than the wall thickness of the hollow shaft portion and form the head in a predetermined shape without impairing the above-described effect of preventing breakage of the connecting portion.

Further, in the third step, the second material formed in the second step is cut and upset to cut the outer peripheral portion of the head up to near the hollow shaft portion to form a head having a predetermined cross-sectional shape. At the same time, if the collar-shaped seat portion is formed to bulge between the head portion and the hollow shaft portion, the wall thickness of the head portion and the
The head part and the collar-shaped seat part can be formed while maintaining the state in which the wall thickness of the connecting portion between the head part and the hollow shaft part is made larger than the wall thickness of the hollow shaft part. The head portion can be formed in a predetermined shape without impairing the above-described effect of preventing the breakage of the connecting portion, and the area of the seat portion can be increased by the collar-shaped seat portion.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a hollow bolt manufactured by a manufacturing method according to the present invention.

FIG. 2 is a side view of the same.

FIG. 3 is a vertical sectional view of a pipe material in the manufacturing process of the hollow bolt.

FIG. 4 is a vertical cross-sectional view of the first material formed in the first step.

FIG. 5 is a vertical sectional view of a second material formed in the second step.

FIG. 6 is a side view of the same.

FIG. 7 is a vertical cross-sectional view of a third material formed in the third step.

FIG. 8 is a side view of the same.

FIG. 9 is a vertical sectional view of a third material formed in a third step of another embodiment.

FIG. 10 is a side view of the same.

FIG. 11 is an explanatory diagram showing another embodiment of the head.

FIG. 12 is an explanatory view showing still another embodiment of the head.

FIG. 13 is a vertical cross-sectional view of a pipe material in a manufacturing process of a hollow bolt manufactured by a conventional manufacturing method.

FIG. 14 is a vertical cross-sectional view of the first material formed in the first step.

FIG. 15 is a vertical cross-sectional view of a second material formed in the second step.

FIG. 16 is a side view of the second material.

[Explanation of symbols]

1 hollow bolt 11 Hollow shaft 12 heads 13 mouth 14 Connecting part (neck part) 15 Collar seat A material B first material B1 hollow shaft B2 head C second material C1 hollow shaft C2 head C3 mouth C4 joint (neck) D third material D1 hollow shaft D2 head D3 mouth

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP 2000-140991 (JP, A) JP 9-122795 (JP, A) JP 11-117922 (JP, A) JP 10-220442 (JP, A) JP 62-187542 (JP, A) JP 57-134232 (JP, A) JP 1-306037 (JP, A) JP 59-17013 (JP, A) Actual Kai 55-160243 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B21J 1/00-13/14 B21J 17/00-19/04 B21K 1/00-31/00

Claims (3)

(57) [Claims] 1. A method of manufacturing a hollow shaft part in which a head is integrally formed from one end of a hollow shaft part from a pipe material, the method having a larger diameter and a larger thickness than an outer diameter of the hollow shaft part of the shaft part. The material is a pipe material having a length shorter than that of the shaft part, and first, in the first step, this material is pushed into the die from one direction to have a thick head at one end and the above-mentioned at the other end. also forms the first material comprising a hollow shaft portion of the thin in diameter than the material, then in a second step, upsetting the head portion while push the forming pins in the first material of the head machining Then, the mouth of the head is expanded and molded into a predetermined shape, and the head and hollow
Without buckling the boundary with the shaft in the radial direction
A method of manufacturing a hollow shaft part, characterized in that the thickness of the head portion and the thickness of the connecting portion between the head portion and the hollow shaft portion are formed to be larger than the thickness of the hollow shaft portion. 2. A second material formed in the second step is subjected to a third step in which a peripheral portion of the head is cut along the entire length of the head to form a head having a predetermined cross-sectional shape. The method for manufacturing a hollow shaft part according to claim 1, wherein 3. A head having a predetermined cross-sectional shape by cutting and upsetting the outer peripheral portion of the head of the second material formed in the second step to near the hollow shaft in the third step. The hollow shaft part manufacturing method according to claim 1, wherein the collar-shaped seat part is formed to bulge between the head part and the hollow shaft part while forming the part.