JPH05231583A - Manufacture of eye bolt for tube joint - Google Patents

Abstract

PURPOSE:To improve productivity, to cut superfluous material, to strengthen a shaft part, and to prevent damage to a screw part by forming a longitudinal hole, head, base, and lateral holes, and then by forming the screw part by rolling. CONSTITUTION:The front end part of a rod material 10 cut into a predetermined length is chamfered by providing a face on the front end part of a shaft part 12 by a header process, and a recessed part is formed in the center of the front end part. A longitudinal hole 16 is formed by header process, and a hexagonal head 11 and a hexagonal hole 11a of the center of the head are formed. Lateral holes 17 of the elliptic shape are formed axially symmetrically at two points by punching so that they orthogonally cross the vertical hole 16 in the vicinity of the bottom. Deburring of the lateral hole 17 is carried out by a shot blast method. A screw part 15 is formed by rolling, on which surface treatment (plating) is carried out, and an eye bolt product is thus manufactured. A material corresponding to the volume of the longitudinal hole 16 is saved, while the cross section of a small diametral part 1 at the position of the lateral hole 17 is increased.

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 eyebolts for pipe joints, and the obtained eyebolts are used, for example, in hydraulic pipes and air pipes of automobiles.

[0002]

2. Description of the Related Art Eyebolts are used as hydraulic pipe joints for automobiles. As shown in the lower right part of FIG. 2, this eyebolt is composed of a hexagonal head 11 and a shaft portion 12 having a circular cross section similar to the headed bolt, and the shaft portion 12 has a base portion 13, a small diameter portion 14 and a tip end. It consists of the screw part 15,
The shaft portion 12 has a vertical hole 16 extending from the tip to the vicinity of the base portion 13 along the center line, and the small diameter portion 14 has the vertical hole 1 described above.
6 are provided with circular lateral holes 17 respectively, and an eye fixed to one end of the oil pipe of the hydraulic system is fitted to the base portion 12 and the small diameter portion 13, and the screw portion 15 is connected to the cylinder. It is designed to be screwed and fixed to the wall of the.

However, the above-mentioned eyebolts have hitherto been manufactured by subjecting a metal rod having a circular cross section to plastic working and cutting. That is (see FIG. 2), in the first step 1S, the rod 10 having a circular cross section is cut into a predetermined length, and in the next second step 2S, the rod 12 is processed into the shaft portion 12 by the first step header processing. Thick diameter base 1
3, the head 11 is formed by the second step header processing in the third step 3S, the threaded portion 15 is formed by rolling in the fourth step 4S, and the fifth step 5
A vertical hole 16 is drilled with a first drill in S, a circular horizontal hole 17 is drilled with a second drill in a sixth step 6S,
In the seventh step 7S, the lateral hole 17 is chamfered with the third drill, and further, the inner surface of the vertical hole 16 is deburred with the fourth drill in the eighth step 8S, and then the surface treatment is performed in the ninth step 9S ( It was plated and finished.

[0004]

Conventionally, since the vertical hole 16 is formed by drill cutting, there is a problem that the material is wasted by the amount of the cutting powder. Also, the shaft portion 12
Since the horizontal hole 17 was formed into a circular shape by drill cutting in the small diameter portion 14 at the position where the cross-sectional area of the horizontal hole becomes minimum and the strength becomes the lowest, the shape of the horizontal hole 17 can be changed in the axial direction without changing the hole area of the horizontal hole 17. It was not possible to improve the strength of the shaft portion 12 by making it a long oval shape. Further, since the drilling was performed after the threaded portion 15 was formed in the fourth step 4S, there was a risk that the threaded portion 15 was damaged. Furthermore, in the past, since plasticity processing such as high-productivity header processing and rolling and low-productivity drill cutting were mixed, the productivity as a whole was low, and moreover cutting chips were produced by the above-mentioned drill cutting. If the chips are generated and the chips remain, the pipes are clogged during use, so that the chips need to be removed, and there is a problem that this removal operation is difficult.

According to the present invention, in the above-mentioned eyebolt manufacturing method, productivity is improved and material waste is eliminated by changing the processing sequence and changing the cutting processing to plastic processing to reduce the number of steps. , Strengthen the shaft 12 and screw 1
5 is prevented from being damaged, the generation of cutting chips is eliminated, and the removal work thereof is unnecessary.

[0006]

The present invention has an outer shape of a headed bolt, the shaft portion of which is composed of a base portion, a small diameter portion and a screw portion at the tip, and from the tip to the vicinity of the base along the center line of the shaft portion. In the method for manufacturing an eyebolt having a vertical hole reaching up to, and having a horizontal hole intersecting the vertical hole in the small diameter portion from a rod having a circular cross section, the vertical hole, head and A method for manufacturing an eyebolt for a pipe joint, characterized in that the base portion is formed by header processing, then the lateral hole is punched to form an oval shape, and then the threaded portion is formed by rolling.

When processing the header of the head, hexagonal holes, square holes, and Torx holes for socket wrenches can be formed. If these holes are provided, the head should be round or flanged. You can In addition, the installation location of the horizontal hole,
It is not limited to two axially symmetric locations (two locations spaced by 180 degrees), but can be provided at one location, two locations that are not axially symmetric, or three or more locations, and two locations that are distant from each other in the length direction. It can be provided at two locations separated in both the direction and the circumferential direction.

[0008]

[Function] Since the vertical holes are formed by header processing, compared to conventional drill cutting, work hardening occurs and the strength of the peripheral wall of the vertical holes increases, and the processing accuracy improves, and the thickness of the peripheral wall becomes uniform. Therefore, the processing speed can be further increased. And
Since the strength of the peripheral wall is increased, the rolling of the threaded portion can be changed to the final step, which reduces the risk of damaging the threaded portion. In addition, since the lateral hole is punched to form an oval shape, it is possible to maintain the same hole area as a conventional lateral hole with a circular diameter and to narrow the width. Therefore, the cross-sectional area of the shaft portion at the lateral hole portion is circular. Increased compared to holes, increased strength, and increased processing speed. And
Since the lateral hole is formed by punching as described above, the conventional drilling process is not required for deburring, and deburring can be performed easily by sandblasting at high speed, thus improving productivity.

[0009]

EXAMPLE As shown in FIG. 1, a rod 10 cut into a predetermined length in the first step 1S is processed in the second step 2S.
In, the tip end of the shaft portion 12 is chamfered by header processing to chamfer the tip edge portion, and a recess is formed at the center of the tip portion. Next, in the third step 3S, the vertical hole 16 is formed by header processing, and the next fourth
In step 4S, the hexagonal head 11 and the central hexagonal hole 11a are formed. The third step 3S
The entire shaft portion 12 may be molded to have the diameter of the base portion 13, and the portion other than the base portion 13 may be molded to have the diameter of the small diameter portion 14 in the next fourth step 4S. The whole is molded into the diameter of the small diameter portion 14, and the base portion 1 is formed in the next fourth step.
3 may be molded with the head 11.

Next, in the fifth step 5S, the oval lateral hole 1 is formed so as to be orthogonal to the vertical hole 16 near the bottom thereof.
7 are punched at two axially symmetric locations. In this case, the shaft portion 12 is inserted into the die, and the vertical hole 1 of the shaft portion 12 is inserted.
A cored bar is inserted into 6. The oval lateral hole 17 is shown in FIG.
Is formed in the same area as that of the circular lateral hole 17 of the above, and in the next sixth step 6S, deburring of the lateral hole 17 is performed by the shot blasting method. Then, the following seventh step 7S
In, the threaded portion 15 is formed by rolling, and then, in the eighth step 8S, surface treatment (plating) is performed to obtain an eyebolt of the product.

In the above method, since the vertical holes 16 are formed by header processing, the material corresponding to the volume of the vertical holes 16 is saved. For example, the outer diameter of the screw portion 15 is 14 mm, the length of the shaft portion 12 is 24 mm, the inner diameter of the vertical hole 16 is 8 mm, and the depth thereof is 24 mm.
For mm eyebolts, header machining the vertical holes 16 saves 23% in material used. Also, the horizontal hole 1
7 is formed into an oval shape, so if the outer diameter of the small diameter part of the eyebolt is 12.9 mm, the conventional circular lateral hole with an inner diameter of 6 mm
By changing 7 to an oval shape having a width of 4.4 mm and a length of 7.6 mm, the cross-sectional area of the small diameter portion 14 at the position of the lateral hole 17 can be increased by 15% without changing the hole area.

However, in the above embodiment, since the hexagonal hole 11a is formed at the same time when the head 11 is formed by the header processing, the material corresponding to the volume of the hexagonal hole 11a can be saved. For example, as the above eyebolt, the distance between the opposite sides of the hexagonal hole 11a is 8 mm, and the depth is 4.8 mm.
In this case, the material required for the head 11 is saved by 12%. Moreover, since the work hardening occurs due to the molding of the hexagonal hole 11a, there is no problem in strength even if the hexagonal hole 11a is provided as described above, and the height of the head 11 is further reduced to further increase the material used. You can save. Further, by providing the hexagonal hole 11a, it is possible to use not only a hexagonal wrench but also a socket wrench when tightening.

In the above method, the first step is cutting, the second to fourth steps are header processing, the fifth step is punching, the sixth step is deburring by sandblasting, and the seventh step is rolling. , 8th
The step is surface treatment, and the production rate of each process is 5 per minute.
Since the number is 0 or more, the productivity is significantly improved as compared with the conventional method including the drilling of 5 to 10 pieces per minute.

[0014]

As described above, according to the present invention, the vertical hole, the head and the base portion of the eyebolt are formed by header processing, then the horizontal hole is punched to form an oval shape, and the screw portion is formed by rolling. Therefore, compared with the conventional method of forming vertical holes and horizontal holes by drill cutting after rolling the screw part, the material used is greatly saved and the cross-sectional area of the shaft part at the position of the horizontal hole is increased. Therefore, the strength can be improved, the processing speed can be further increased, and the productivity can be improved, and damage to the screw portion can be avoided. Further, as shown in the embodiment, when the hexagonal hole is provided in the head of the eyebolt, the material used can be further saved and the socket wrench can be used.

[Brief description of drawings]

FIG. 1 is a process explanatory view of the present invention.

FIG. 2 is a process explanatory diagram of a conventional method.

[Explanation of symbols]

10: bar material, 11: head, 11a: hexagonal hole, 12: shaft part,
13: base part, 14: small diameter part, 15: screw part, 16: vertical hole, 17: horizontal hole.

Claims (1)

[Claims] 1. An outer shape of a headed bolt, the shaft portion of which includes a base portion, a small diameter portion and a screw portion at the tip, and a vertical hole which extends from the tip to the vicinity of the base along the center line of the shaft portion,
And in the method of manufacturing an eyebolt provided with a horizontal hole that intersects the vertical hole in the small diameter portion from a rod having a circular cross section, the vertical hole, the head and the base portion of the rod are molded by header processing, Next, a method for manufacturing an eyebolt for a pipe joint, characterized in that the lateral hole is formed into an oval shape by punching, and then the threaded portion is formed by rolling.