JPH08238534A - Production of stud bolt - Google Patents

Abstract

PURPOSE: To execute a mass production and to improve the quality of material by forming a stud bolt by cold forging. CONSTITUTION: The production is performed by cutting (A) a wire of a definite size in a definite length and obtaining a 1st raw material, and a forward extruding (B) to form a small diameter part 2c by pressing one side of the raw material into a die 21 and making one side smaller than a shaft part 2b, a sphere pre-forming (E) composed of a 1st pre-forming (C) and a 2nd pre-forming (D) of upsetting the small diameter part 2c toward the shaft part 2b, and a shaft part pre-forming composed of a bolt part pre-forming (E) and a bolt part forming (F) of swaging bolt parts 5b, 6b and tool engage parts 5f, 6f on the shaft part 2b. Further, the stud bolt is worked with the process to form one body by connecting the bolt parts 11, 12, 13 and a spherical ball 15 part with the small diameter part 14 by forming a male screw 12 on the bolt shaft part 7b after lapping (G) a sphere pre-formed ball 4r part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ball joint which is widely used for automobile parts or machine parts, and more particularly to a method for manufacturing a bolt used as a ball stud.

[0002]

2. Description of the Related Art As shown in FIG. 1, a stud bolt 10 which has been generally used in the past has a hexagonal tool engaging portion 11 and a screw portion 12, and a tool engaging portion with a small diameter portion 14. The part 11 and the ball part 15 are connected and integrated. Reference numeral 13 denotes an end portion, which is a portion in which a screw is not formed, but which is not shown but serves as a guide when screwed into a screw hole, and may be functionally not necessary.
The ball portion 15 is formed with a ball-shaped socket member (not shown) and a ball joint which can be freely rotated or tilted like a joint.

This stud bolt 10 has a
21726, Japanese Patent Publication No. 47-11002 and Japanese Patent Publication No. 5
As disclosed in Japanese Patent Laid-Open No. 3-8861, a bolt composed of a small diameter portion 14 and a screw portion 12 connected to a tool locking portion 11 is friction welded to a ball 15 at the end of the small diameter portion 14. Or integrally molded, or bolts (11,
12, 13), the small diameter portion 14 and the entire ball 15 portion are cut.

[0004]

As described above, when the balls 15 are friction-welded to the small diameter portion 14, the rotation of the axial side of the bolt can be performed by gripping the tool engaging portion 11. However, it is difficult to hold the spherical ball 15 because it cannot rotate, and it rotates together with the rotation of the bolt side, so the temperature rise necessary for friction welding cannot be expected sufficiently, so the required welding strength can be obtained. I can't.

Further, when the small-diameter portion 14 and the ball 15 are formed by cutting, cutting streaks formed by cutting remain, the strength is reduced in the small-diameter portion 14, and the streak is formed in the ball 15 part. Is an oil reservoir, which is convenient for lubrication, but the streak wears early, and rattling occurs early in the fitting state with the socket member.

Therefore, the present invention proposes a method of manufacturing a stud bolt which can be mass-produced by forming a stud bolt 10 from a wire material having a constant thickness and which can improve the yield rate and quality (strength) of the material. It is a thing.

[0007]

The present invention, which has been made in view of the above circumstances, will be described with reference to FIG. 2. A wire material having a constant thickness is cut (A) into a constant length to obtain a first material ( 1) is obtained, and one side of the material is pushed into a mold (21) to form a small diameter portion (2c) thinner than the shaft portion (2b) on the one side, and a front extrusion process (B), Spherical preforming including a first preforming (C) and a second preforming (D) for setting a small diameter portion (2c) in the direction of the shaft (2b), and ironing the shaft (2b). Then bolt shaft (5b, 6
b) and a shaft part preforming including a bolt part preforming (E) and a bolt part forming (F) for setting the tool locking parts (5f, 6f), and further, the spherical preformed ball (4r). ) Part is lap-formed (G), and then a male screw (12) is formed on the bolt shaft part (7b),
Bolts (11, 12, 13) and spherical balls (15)
The part is a method of manufacturing the stud bolt (10) by a step of being integrally formed by being connected to the small diameter part (14).

[0008]

The tool engaging portion (11) and the ball (15) are formed by the forward extrusion process (B) according to the present invention and the spherical preform formed by the first preform (C) and the second preform (D). It is possible to cold forge the small diameter part (14) that connects the parts,
Since the small diameter portion (14) connects the ball (15) portion and the tool locking portion (11) with a smooth radius without a boundary, the ball (15) portion and the small diameter portion (14) are particularly connected. The strength of the connecting portion is improved and the quality is improved.

Further, since the ball (15) portion is rolled to correct the spherical shape by the lap molding (G), the ball (15) portion forms a smooth spherical surface and fits with the socket member. It can be maintained smoothly.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The relationship between the order of steps and the mold according to the order of steps will be described below with reference to FIGS.

First, as shown in FIG. 2, a cutting step (A)
A wire material having a certain thickness is cut into a certain length to obtain the first material 1. Then, the material 1 is inserted into the hole of the die 21, and the end portion 1a is pushed by the push pin 22 in the arrow direction (right direction in the drawing) to perform forward extrusion processing (B) to the position 2a (see FIG. 3). Then, the shaft portion 2b and the small diameter portion 2c are formed, and the second material 2 is obtained. Reference numeral 23 denotes an extruding pin that contacts the tip 2d of the small diameter portion 2c to determine the length of the small diameter portion 2c, and after the push pin 22 is pulled back from the forward position, the pushing pin 23 advances. By moving (moving to the left in the arrow direction), the second material 2 is discharged from the die 21 from the shaft portion 2b side.

Then, a first preforming (C) and a second preforming are carried out. That is, as shown in FIG. 4 (schematically in a parallel state in the drawing), the disk-shaped table 30 is equally divided to provide holes at at least four positions, and the dies 31a, 32a ... ... 31d and 32d can be expanded in the arrow direction (vertical direction in the drawing) with the dies 31 and 32 as one set, and the shaft portion 2b and the small diameter portion 2c of the second material 2 can be gripped like a collet. Has become. Then, the four holes are classified into, for example, a standby stage, a first preforming stage (C), a second preforming stage (D) and a discharging stage depending on the position of the rotating table 30.

That is, in the first stage, the die 31
The second material 2 is inserted into and gripped by a and 32a. In addition, in the second stage, the second material is set to the dies 31b, 3
When it is gripped by 2b and the small diameter portion 2c is aligned with the hole of the pressing die 33 and both dies 31b, 32b and 33 come into contact with each other, the punch 35 strongly presses the tip 2d and the ball 3r.
Move in part (C). Further, in the third stage, the tip 3d of the third material 3 processed in the second stage is processed (D) with the punch 41, and the ball 4r portion formed by the punch 41 and the dies 31c, 32c. To mold. Then, although not shown, after discharging the fourth material held by the dies 31d and 32d in the fourth stage,
The table 30 is rotated by 90 ° and the above-mentioned processing is repeated.

The first preforming (C) in the second stage and the second preforming (D) in the third stage.
Then, press the punches to press the end parts 3a and 4a respectively.
When pressure is applied in the 1st and P2 directions, the molding accuracy of the balls 3r, 4r is improved. Further, the tip ends 3a and 4a are substantially the same as the shaft portion 2b of the second material 2 in the spherical preforming, and the shaft portions 3b and 4b are not the parts to be molded together. And lowercase letters (the same applies below).

Then, as in the case of forming the shaft portion, at least standby, bolt portion preforming (E), and bolt portion forming (F) are carried out.
And, it is composed of four discharge stations. Since the above-mentioned process is a process of spherical preforming, the shaft portion 2b side was grasped, but in the shaft portion forming, the shaft portion 4b which becomes the bolts 11, 12, and 13 is squeezed, and the tool engaging portion 7f is set up. This is a process for doing.

In this shaft forming, as shown in FIG. 5, the gripping dies 51, 52 are set as one set, and the gripping dies 51a,
The reference numeral 52a can be expanded vertically as shown by an arrow, and can be clamped on the opposite side to grip the ball 4r portion of the fourth material 4. The product can be released by the expansion, and the gripping die 5 is used in the second and third stages.
1b, 52b and 51c, 52c are incorporated in the table 50 so as not to spread. Then, in the first stage, the above-mentioned fourth material 4 is held by the gripping dies 51a and 52a.
In the state where the ball 4r part is gripped and the shaft part 4b thereof is projected, a gap S is formed around the gripping dies 51a and 52a.
The gap S is formed from the tool engaging portions 5f, 6f side to the small diameter portions 5c, 6c when the bolt portion preforming (E) and the bolt portion forming (F) in the second stage and the third stage are performed.
It is connected to the side with a smooth radius, and the flow of the material to the side of the small diameter portions 5c and 6c is allowed freely.

Although not shown, the table 50 has grip dies 51a, 52a ...
2d is moved to the right with respect to FIG. 5 to release the contact between the molding die 53 and the receiving die 62, which face each other, and to rotate. As another method, a transfer device may be used to linearly move and the gripping and releasing may be repeated for each station. However, the description will be given here as a disk-shaped table 50.

In the standby state, the fourth material 4 is gripped by the dies 51a and 52a as described above, and in the second stage, the fourth material 4 is pushed into the forming die 53 and the end portion 4a is pressed by the punch 54. Then, by preliminarily upsetting the tool engaging portion 5f, the tool engaging portion 5f and the small diameter portion 5c are filled with a smooth radius so as to fill the gap S. Similar to the second stage, in the third stage, the fifth material is pushed into the hole of the receiving die 62, and the meat of the corner portion 5e is pushed to the tool engaging portion 6f side. When the tool engaging portion 6f is slid, the material tends to extend in the direction of the guide portion 6g and the end portion 5a is pressed by the punch 63 in order to make the sled sufficiently.
Also in b, molding is performed to a stable size (length). In addition,
The punches 54, 63 press the end portions 5a, 6a to be formed, and the tool engaging portions 5f formed by the forming die 53, the receiving die 62 and the gripping dies 51, 52 facing each other,
The purpose is to bury the material in 6f, but when the table 50 releases the contact with the forming die 53 and the receiving die 62 which face each other and moves away, the punches 54, 63 are moved.
Is used as a knockout pin. Then, in the fourth stage (not shown), gripping dies 51d, 52
The sixth material 6 gripped at d is released and released, and at the same time, the fourth material 4 is gripped on the first stage and stands by, and these steps are repeated to form the shaft portion.

As mentioned above, the shaft portion is formed by the shaft portion 4b of the fourth material 4.
If the thickness (corresponding to the thickness of the first raw material 1) is large, in the bolt part preforming (E), the shaft part 4b is ironed and extruded from one side at the same time, and the screw is formed. The shaft is preformed to a certain thickness.

Further, in the above spherical preforming (E, F),
This is performed when the ball 4r portion of the fourth material 4 is not sufficiently shaped, that is, when the ball 4r portion has no roundness in the spherical preforming, and an example thereof is shown in FIG. There is. In the illustrated example, the ball 7r portion and the small diameter portion 7c are formed by the flat plate-shaped grooves 71a and 72a facing each other.
The lap plates 71 and 72 capable of sandwiching are moved in parallel to each other and while applying pressure (arrows indicate from both sides) toward the center of the ball 7r. Then, by repeating the rolling of the sixth material 6 in the direction of the arrow, the groove 71
A ball portion 7r having a spherical roundness is formed and finished in a shape formed by a and 72a.

In the lap forming (G) process, the lap plate 7
The circularity can be obtained by moving 1 and 72 in directions opposite to each other, or by fixing one side and allowing the other side to move freely. Alternatively, instead of the lap plates 71 and 72, the grooves 71a and 72 are formed on the rollers.
It is also possible to provide a and perform spherical molding while rolling the roller.

A finished product 8 is obtained by forming the male screw 8h on the shaft portion 7b of the seventh raw material 7 by the lap forming (G) process by rolling. Since the roll transfer (H) is also commonly performed, its description is omitted.

In the above process, after cutting the material (A),
Although the spherical preforming (C, D) processing is performed to perform the shaft forming (E, F) processing, the spherical forming processing may be performed after the shaft forming. Further, it is needless to say that the lap forming (G) process can be omitted if the spherical precision can be obtained by the spherical preforming (C, D) process.

Further, during the main forming process, the raw material is subjected to heat treatment, heat treatment, phosphoric acid film treatment, or the like, if necessary. In particular, the phosphoric acid film treatment improves the slippage of the material during upset processing, and the shape familiar with the mold can be accurately formed, so that the processing accuracy is improved and the quality is greatly improved.

[0025]

As described above, according to the method of manufacturing a stud bolt of the present invention, the wire rod is cut into a certain length, the material is extruded forward, and then the spherical preforming and the shaft portion forming are performed. Therefore, since the axial fiber structure formed in the wire is effectively plastically deformed, the structure can be densified by forging, and the strength can be expected to improve by the processing. Further, since the surfaces of the small diameter portion and the ball portion are smooth, and the small diameter portion which is the connection between the tool locking portion and the ball portion is connected with a smooth radius, the strength of the small diameter portion is also improved. Therefore, the ball portion can be made to have a small diameter or the bolt portion can be made thin. In addition, the processing steps can be lined up for mass production, while maintaining uniform product quality for production.

Further, in the lap molding, since the roundness of the ball portion and the smoothness of the spherical surface are improved, the ball of the stud bolt and the socket member fitted therein are smoothly lubricated.

[Brief description of drawings]

1 is a side view of a product according to the present invention.

FIG. 2 shows a manufacturing method according to the present invention in the order of steps (A) to
(G) is a side view of a molded product formed in the step and an explanatory view of a processing method.

FIG. 3 is a process (B) front extrusion mold in FIG. 2 and a processing state diagram thereof.

FIG. 4 is a step (C) first preforming in FIG. 2, (D)
The schematic diagram of the spherical preforming process of the second preforming.

FIG. 5 is a step (E) bolt preforming in FIG.
(F) Schematic diagram of the shaft forming process of the bolt forming

FIG. 6 is a cross-sectional view of a lap plate subjected to a step (G) lap forming process in FIG.

[Code]

 1 1st material 2 2nd material 2b Shaft part 2c Small diameter part 4r Ball (part) 5b, 6b, 7b (Bolt) Shaft part 5f, 6f Tool locking part 8, 10 (Completed) Stud bolt 11 Tool locking Part 12 Male screw 13 Guide part 14 Small diameter part 15 Ball (part) 21 Mold (die) A Cutting B Forward extrusion C First preform D Second preform E Bolt part preform F Bolt part G Lap forming H thread rolling

[Procedure amendment]

[Submission date] May 10, 1996

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

[Correction content]

[0001]

The present invention relates to relates to a Tamase' hand are widely used in automotive parts or mechanical parts, and more particularly to a manufacturing method of a bolt which is used as the ball stud.

Claims (1)

[Claims] 1. A method of manufacturing a stud bolt, comprising: a male screw part and a tool locking part, wherein the tool locking part is integrally formed with a ball part connected through a small diameter part. A front extrusion process in which a first material is obtained by cutting a wire having a thickness into a certain length, and one side of the material is pushed into a mold to form a small diameter portion thinner than a shaft portion on the one side, A spherical preform formed by first preforming and second preforming for inserting the small-diameter portion in the axial direction, and ironing the shaft portion to insert the bolt shaft portion and the tool locking portion. Shaft part preforming including bolt part preforming and bolt part forming, and further, after forming the spherical preformed ball part by lap forming, by forming a male screw on the bolt shaft part, the bolt part and the spherical shape are formed. The ball part of is connected with the small diameter part and integrally molded Made, method of manufacturing the stud bolt.