JP2006170331A - Bolt with locking projection, and its manufacturing method and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bolt with a locking projection capable of being manufactured with cold forging and extremely superior in strength, and to provide its manufacturing method and device. <P>SOLUTION: The manufacturing method mainly comprises semi-close upsetting work with cold forging. In primary work, a thick portion is formed on one side face of the upper part of a blank P to provide for the locking projection 3. In second work, a thick portion is formed to provide for a bolt head 2. In third work, a molded recessed portion 4 is formed in the center at the upper end of the blank P to be recessed in a concentrically circular shape. Together with the molded recessed portion 4, the bolt head 2 is formed at the thick portion around the molded recessed portion 4. The locking projection 3 is molded together with the bolt head 2 at the same time. In fourth work, the bolt head 2 and the locking projection 3 are re-shaped. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is, for example, attached to an end portion of a fixing ring that is wound around and fixed to an opening of a drum can or a fastening band that is wound around and fixed to a side surface of a utility pole, and is used when tightening these rings and bands. The present invention relates to a bolt with a stop projection, a manufacturing method thereof, and a manufacturing apparatus.

  Conventionally, it is attached to the end of a fixing ring that wraps around the opening of a drum can and fixes the lid, or a fastening band that wraps around the side of the utility pole and fastens, and is used to tighten these fixing rings and tightening bands. As a bolt with a locking projection, for example, a bolt with a stopper described in Patent Document 1 is used.

  This bolt with a stopper is provided with a bent portion at an open end of a fixing ring wound around a drum can or the like, and the bolt is inserted between the bent portions to be tightened. The bolt with a retaining portion described in the cited document 1 has a pointed projection for spot welding formed on one surface of the retaining portion formed in a plate shape, and the pointed projection and the peripheral side surface of the bolt head are formed. It is formed so as to be spot welded.

  As a manufacturing method in which a bolt having a special shape is formed by a forging means without using a welding means, for example, there are manufacturing methods described in Patent Document 2 and Patent Document 3. The manufacturing method described in Patent Document 2 is a manufacturing method in which, in an eyebolt composed of a ball head and a handle, the handle is finished by cold forging and the ball head excluding the handle is warm forged. It is. In such a manufacturing method, the strength of the handle portion finished by cold forging can be increased, and the ball head formed by warm forging can be easily molded.

On the other hand, the manufacturing method described in Patent Document 3 relates to a method for manufacturing a high-strength connector bolt. A connector is obtained by subjecting a cylindrical pipe material to cold forging drawing or cold forging upsetting. A method of manufacturing a bolt is described.
Japanese Patent Laid-Open No. 10-184640 Japanese Patent No. 2517405 Japanese Patent No. 30233353

  The bolt with a retaining portion described in Patent Document 1 has a pointed projection for spot welding formed on one surface of a retaining portion formed in a plate shape, and the pointed projection and the peripheral side surface of the bolt head If the bolt is tightly tightened when it is used repeatedly and metal fatigue occurs in the welded part, or when welding is insufficient, the stop part will become the bolt head. There was a risk of detachment.

  On the other hand, according to the manufacturing method by forging as in the manufacturing methods described in Patent Document 2 and Patent Document 3, it is possible to manufacture a bolt having higher strength than the welding means. However, when the bolt head is molded by warm forging as in Patent Document 2, the strength may be inferior to that of cold forging. In other words, in cold forging, it becomes possible to forge by making use of the fiber structure of the blank to be forged without cutting, and the strength perpendicular to the fiber structure can be increased, but in warm forging, molding is easy. However, since this fiber structure is cut, the strength is inferior to that of cold forging. Therefore, when forging a bolt, the manufacturing method using cold forging can increase the strength of the bolt rather than warm forging.

  However, even in the manufacturing method using cold forging as in the manufacturing method of Patent Document 3, it is difficult to make use of the fiber structure of the wire in the manufacturing method using a cylindrical pipe material. That is, the fiber structure of the blank is one in which the fiber structure is continuously formed along the longitudinal direction of the blank when the rod-shaped blank is formed by rolling from the ingot, and without cutting this fiber structure. The strength of the bolt can be increased by utilizing it. Therefore, when the pipe material is cold-forged as a blank as in the cited document 3, the fiber structure has already decreased at the time of forming the pipe material, so it is impossible to obtain the strength utilizing this fiber structure. .

  In order to form a specially shaped bolt with a locking protrusion on the side of the head, such as a bolt with a stopper described in Patent Document 1, by cold forging, the manufacturing method utilizing this fiber structure is strong. In addition, it is extremely effective. However, when trying to cold forge such a bolt, when the locking projection is formed, a large burr is generated, the meat does not move in the direction of the locking projection, the head is greatly eccentric, etc. It was difficult to make adjustments, and the middle stage of the manufacturing process was forced. In addition, when the head is greatly eccentric, there is a possibility that the fiber structure is cut, so that the strength may be lowered. As a result, in the forging method of the bolt with the locking projection, it is considered that cold forging using a fiber structure is not practical. At present, warm forging that is easy to process is used, or as disclosed in Patent Document 1, A bolt with a locking projection in which the locking projection is welded after forging has been used.

  Therefore, the present invention was created to solve the above-described problems, and enables the production of a bolt with a locking projection by cold forging, and provides a bolt with a locking projection with extremely high strength, its manufacturing method, and a manufacturing apparatus. It is for the purpose of provision.

  The first means of the present invention comprises a bolt shaft portion 1 and a bolt head portion 2 formed by cold forging from a blank P of a rod-shaped material, and the bolt shaft portion 1 direction from the outer surface of the bolt head portion 2. In the bolt with the locking protrusion formed integrally with the bolt head 2, the fiber structure at the time of the blank P extends from the center of the top of the bolt head 2 along the longitudinal direction of the bolt shaft 1. The bolt with the locking projection provided so as to remain continuously.

  The second means comprises a bolt shaft portion 1 and a bolt head portion 2 which are forged from a blank P made of a rod-shaped material, and a locking projection extending from the outer surface of the bolt head portion 2 toward the bolt shaft portion 1. In the manufacturing method of the bolt with a locking projection formed integrally with the bolt head 2, the locking projection 3 is applied to the upper side surface of the blank P by performing a primary process by semi-sealing upsetting of cold forging. Forming a thick portion for the bolt head 2 by secondary processing, and forming a concave portion 4 for concentrically denting the center of the upper end of the blank P by tertiary processing. At the same time, the bolt head 2 formed from the thick portion around the molding recess 4 and the locking projection 3 formed to protrude outside the bolt head 2 are simultaneously molded and processed by the fourth processing. Adjust the shape of the bolt head 2 and the locking projection 3 to the outer periphery of the bolt shaft 1. In the manufacturing method of forming a male thread 5 subjected to granulation processing.

  The third means comprises a bolt shaft portion 2 and a bolt head portion 1 formed by forging from a blank P made of a rod-shaped material, and a locking projection extending from the outer surface of the bolt head portion 2 toward the bolt shaft portion 1. 3 is attached to the bottom of the die 10 holding the blank P and stored in the die 10 in the bolt manufacturing device with the locking projection formed integrally with the bolt head 2 by semi-sealing upsetting of cold forging. The manufacturing apparatus provided with a fixing device 20 for fixing the position of the blank P in the rotational direction with respect to the die 10.

  The fixing device in the fourth means is a knockout pin 21 that is rotatably mounted vertically below the blank P, bites into the lower end of the blank P, and fixes the position of the blank P in the rotational direction with respect to the die 10, and a planar donut The knockout pin 21 is passed through the axial center of the shape, and the pin holder 24 that fixes the rotational position of the knockout pin 21 is crimped from the side surface of the die 10 to the side surface of the pin holder 24 to adjust the rotational position of the pin holder 24 It is a means for solving the problem to be composed of the fastening bolts 25 to be fixed.

  According to claim 1 of the present invention, it is possible to provide a bolt with a locking projection having high strength exceeding the welding means and the warm forging means.

  According to the manufacturing method of claim 2, it is possible to overcome many problems such as generation of large burrs, eccentricity of the head, cutting of the fiber structure, etc. that have occurred in the cold forging so far, It became possible to stably supply bolts with locking projections.

  In the manufacturing apparatus according to claims 3 and 4, the positional deviation in the rotational direction of the blank P generated when molding the locking projection 3 protruding from one side of the bolt head 2 is prevented, and the locking is performed with high accuracy. Protruding bolts can be manufactured.

Thus, according to the present invention, it is possible to produce a bolt with a locking projection by cold forging, and there are various effects such as providing a bolt with a locking projection that is extremely strong and excellent in accuracy. Is.

  In the best mode of the manufacturing method of the present invention, a primary processing by semi-sealing upsetting of cold forging is performed to form a thick portion for the locking projection 3 on the upper side surface of the blank P. A thick part for the bolt head 2 is formed by secondary processing. By the third processing, the molding concave portion 4 is formed to concave the center of the upper end portion of the blank P concentrically. The bolt head 2 formed from the thick portion around the molding recess 4 and the locking projection 3 formed to protrude outside the bolt head 2 are simultaneously molded together with the molding recess 4. The shape of the bolt head 2 and the locking projection 3 is adjusted by the fourth processing. The initial purpose is achieved by forming the male screw 5 by rolling the outer periphery of the bolt shaft portion 1.

  In the bolt of the present invention, a bolt shaft portion 1 formed by cold forging from a blank P of a rod-shaped material, a bolt head portion 2, and a locking projection 3 provided on a side surface of the bolt head portion 2 are integrally formed. (See FIG. 1). The locking projection 3 extends from the outer surface of the bolt head 2 in the direction of the bolt shaft 1 and is fastened by being wound around the opening of the drum can and fixing the lid, or by being wound around the side of the utility pole and fixed. Used as a detent or locking means when mounted on the end of a band or the like (see FIG. 2).

  The blank P before forging the bolt of the present invention has a rod shape in which the fiber structure is continuous in the longitudinal direction, and the bolt of the present invention is formed from the center of the top of the bolt head 2 to the bolt shaft 1. It is provided so as to remain continuously along the longitudinal direction (see FIG. 3). The manufacturing method of the present invention is a manufacturing method in which the fiber structure of the blank P is utilized in the bolt with the locking portion through the following steps.

  The manufacturing method of the present invention is a manufacturing method by cold forging, and uses semi-hermetic upsetting and rolling. In the semi-sealing upsetting process, the bolt with the locking portion is formed by the following four stages of processing.

  In the primary processing, a thick portion a for the locking projection 3 is formed on one side of the upper portion of the rod-shaped blank P shown in FIG. 3 (a) (see FIG. 3 (b)). As the rod-shaped blank P, one in which the fiber structure is continuous along the longitudinal direction of the blank P is used. The thick portion a is sequentially molded by the following secondary processing and tertiary processing, and finally the locking projection 3 is formed.

  The secondary processing is a step of forming a thick portion b for the bolt head 2 (see FIG. 3C). In this step, the upper end portion of the blank P is pressed, and the thick portion b where the diameter of the blank P at the position where the thick portion a is provided is uniformly expanded is provided. In the example of illustration, it has provided in the shape expanded so that it might become near the lower end part of the latching protrusion 3. FIG.

  The third processing is a step of forming a molding concave portion 4 in which the center of the upper end portion of the blank P is concentrically recessed, and is the most important step in the manufacturing method of the present invention (see FIG. 4D). In this process, the molding recess 4 is formed, and the bolt head 2 and the locking projection 3 are simultaneously molded. The molding recess 4 is formed in order to form the bolt head 2 while maintaining the fiber structure along the axis of the blank P. That is, by pressing the molding recess 4, the thickness of the bolt head 2 can be increased substantially uniformly without cutting the fiber structure along the axis of the blank P. In the experiment, the surrounding thickness can be made more uniform if the molding recess 4 is formed in a substantially mortar shape as shown in the drawing.

  At this time, when forming a bolt head 2 having a diameter of 15 mm and a thickness of 9 mm, the depth of the molding recess 4 is set to 1 to 3 mm, and a uniform bolt head 2 is formed within a diameter of 7 to 9 mm. It was found that can be formed. Then, the bolt head 2 is simultaneously molded from the thick portion b around the molding recess 4. Further, as the bolt head 2 is molded, a locking projection 3 is also molded on the outside of the bolt head 2. In the illustrated example, the bolt shaft portion 1 is drawn, but this processing is arbitrarily selected according to the design.

  In the fourth processing, the outer shape of the bolt head 2 and the locking projection 3 is cut into a predetermined shape to adjust the shape of each part (see (e) in the figure). The bolt head 2 is usually formed in a hexagonal shape, and the locking projection 3 is adjusted to a width, thickness, and length according to the purpose of use (see FIG. 4).

Next, the external thread 5 is formed on the outer periphery of the bolt shaft 1 by rolling or the like (not shown).
The male screw 5 is formed on the bolt shaft portion 1 formed into an arbitrary diameter by the third drawing process, and the bolt of the present invention is finished by forming the male screw 5.

  In the manufacturing method of the present invention, as described above, the die 10 and the punch 30 are replaced many times during the semi-sealing upsetting process. Therefore, when forming the locking projection 3 on one side surface of the blank P, it is necessary to always adjust the molding position of the locking projection 3 to an accurate position. Therefore, the manufacturing apparatus of the present invention includes a fixing device 20 that adjusts the molding position of the blank P.

  That is, the fixing device 20 in the manufacturing apparatus of the present invention is a device that adjusts and fixes the position of the blank P accommodated in the die 10 in the axial rotation direction with respect to the die 10. The fixing device 20 is mounted on the bottom of the die 10 that holds the blank P, and includes a knockout pin 21, a pin holder 24, an adjustment bolt 25, and the like (see FIG. 5).

  The knockout pin 21 is a member that is rotatably attached to the bottom portion of the die 10, is fitted to the lower end portion of the blank P, and fixes the position of the blank P in the rotational direction with respect to the die 10. The upper end portion of the knockout pin 21 is formed so as to form a minus driver-like fitting projection 21A, for example, as shown in the figure, and bite into the lower end portion of the blank P during the first processing. In this way, a fitting recess P1 that fits into the upper end of the knockout pin 21 is formed at the lower end portion of the blank P (see FIG. 3B), and the fitting recess P1 is formed in the knockout pin 21 in a subsequent process. By fitting, it becomes possible to always keep the direction of the blank P constant.

  Furthermore, a planar circular storage portion 22 orthogonal to the knockout pin 21 is formed at the bottom of the die 10 (see FIG. 7). Then, a planar donut-shaped pin holder 24 to be accommodated in the accommodating portion 22 is provided, and the knockout pin 21 is attached to the axial center portion of the pin holder 24 opened. In the illustrated example, the side surface of the knockout pin 21 is D-cut to provide a flat portion 21B. Further, a screw hole 24A is opened in the side surface of the pin holder 24, and a hollow set bolt 24B and a fixing body 23 are inserted into the screw hole 24A, and the tip of the fixing body 23 is brought into contact with the flat portion 21A of the knockout pin 21. By making contact, rotation of the knockout pin 21 is prevented (see FIG. 6).

  The blank P whose rotational position is fixed by the knockout pin 21 is taken out from the die 10 in each step and transferred to the die 10 in the next step when the first process to the fourth process. Therefore, in order to take out the blank P from each die 10, it is necessary to raise the knockout pin 21 inside the die 10. Therefore, the knockout pin 21 is held in such a way that it can move in the vertical direction, although its rotational position is fixed by the pin holder 24 (see FIG. 6).

  On the other hand, a fastening bolt 25 is screwed from the side surface of the die 10 toward the pin holder 24, and the rotational position of the pin holder 24 is fixed by the fastening bolt 25 that is crimped to the side surface of the pin holder 24 (see FIGS. 6 and 7). ). Thus, by adjusting the rotational position of the knockout pin 21 with the rotational position of the pin holder 24, the rotational position of the blank P can be adjusted extremely reliably and easily. For example, when the locking protrusions 3 are sequentially formed in each step, the position of the thick portion a that forms the locking protrusions 3 tends to slightly shift in the rotational direction from the original position of the blank P. If the rotational position of the blank P is fixed without canceling this shift and the process proceeds to the next step, the shape of the locking projection 3 may gradually be deformed. Therefore, by adjusting the position of the pin holder 24 attached to each die 10 in advance in accordance with this shift, a very accurate bolt with a locking portion can be molded.

  In addition, each structure of the example of illustration is only one Example of this invention, It can change freely in the technical range currently known, such as a design change other than the main structure part of this invention, and a change of a form. Is.

It is a front view which shows one Example of this invention bolt. It is a schematic plan view which shows the use condition of the volt | bolt of this invention. It is process drawing which shows one Example of this invention manufacturing method. It is a top view which shows the formation process of the latching protrusion by this invention manufacturing method. It is side sectional drawing which shows one Example of this invention manufacturing apparatus. It is a sectional side view which shows one Example of the fixing device in this invention manufacturing apparatus. It is a plane sectional view which shows one Example of the fixing device in this invention manufacturing apparatus.

Explanation of symbols

P blank P1 fitting recess a thick part b thick part 1 bolt shaft part 2 bolt head 3 locking projection 4 molding recess 5 male screw 10 die 20 fixing device 21 knockout pin 21A fitting projection 21B flat part 22 storage part 23 Fixed body 24 Pin holder 24A Screw hole 24B Hollow set bolt 25 Fastening bolt 30 Punch

Claims (4)

  It consists of a bolt shaft part and bolt head molded from a bar-shaped blank by cold forging, and a locking projection that extends in the direction of the bolt shaft part from the outer surface of the bolt head is integrated with the bolt head In the bolt with a locking projection formed in the above, with a locking projection, the fiber structure at the time of blanking is provided so as to remain continuously from the center of the top of the bolt head along the longitudinal direction of the bolt shaft portion. bolt.   A locking projection formed by a bolt shaft forged from a blank of a rod-shaped material and a bolt head, and a locking projection extending in the direction of the bolt shaft from the outer surface of the bolt head is formed integrally with the bolt head. In the manufacturing method of the bolt with a stop projection, the first processing by the semi-sealing upsetting process of cold forging is performed to form a thickened portion for the locking projection on the upper side surface of the blank, and by the second processing, A thickened portion for the bolt head is formed, and a third concave portion is formed to form a concave portion for concentric depression of the center of the upper end portion of the blank, and the thickened portion for the bolt head around the molded concave portion. The bolt head formed from the bolt and the locking projection formed to protrude outside the bolt head are molded at the same time, and the shape of the bolt head and the locking projection is adjusted by the fourth processing, and the bolt shaft Form a male thread by rolling the outer periphery of the part. Method for producing a locking projection bolt, characterized in.   Cold forging semi-enclosed upsetting process for locking projections, which consist of bolt shafts and bolt heads that are forged from rod-shaped blanks and extend from the outer surface of the bolt heads toward the bolt shafts In the manufacturing apparatus of the bolt with a locking projection formed integrally with the bolt head, the fixing device is mounted on the bottom of the die holding the blank and fixes the position of the blank stored in the die in the rotational direction. An apparatus for producing a bolt with a locking projection, which is provided. The fixing device is rotatably mounted vertically below the blank, and a knockout pin that bites into the lower end portion of the blank and fixes the position of the blank in the rotational direction with respect to the die, and a planar circular storage portion orthogonal to the knockout pin The knockout pin is passed through the shaft center of a flat donut shape, and the pinholder that fixes the rotation position of the knockout pin is crimped from the side of the die to the side of the pinholder, and the rotation position of the pinholder is adjusted. The manufacturing apparatus of the bolt with a latching protrusion of Claim 3 comprised from the fastening bolt which carries out.

Images