JP2020163445A - Method of manufacturing headed part - Google Patents

Abstract

To provide a method of manufacturing a headed part that is less likely to create burr on a seat surface, which is likely to occur in rolling of a relief groove in a shaft part.SOLUTION: A method of manufacturing a headed part according to the present invention includes a pressing step of integrally molding a large-diameter shaft part 1 of a large diameter and a small-diameter shaft part 2 of a substantially same diameter as a wire rod 5 by pressing the wire rod 5 of a prescribed diameter in an axial direction, and a rolling step of molding an annular relief groove 3 in the small-diameter shaft part 2. The rolling step is a process of flowing an excess thickness 2a of the small-diameter shaft part 2 that was created in the molding step of the relief groove 3 toward the large-diameter shaft part 1. This enables the excess thickness 2a created in the rolling step to be taken into the large-diameter shaft part 2, thus providing an advantage of causing no waste such as disposal of a material.SELECTED DRAWING: Figure 4

Description

The present invention relates to a method for manufacturing a headed part having a relief groove under the neck.

Conventional methods for manufacturing headed parts are disclosed in Patent Document 1 and Patent Document 2. First, the method for manufacturing a headed part disclosed in Patent Document 1 includes a first pressing step of integrally molding a large-diameter shaft portion and a small-diameter leg portion by pressing a wire rod having a predetermined diameter in the axial direction. A second pressing step of loosely fitting and holding the leg portion and pressing it from the tip side of the leg portion to form a small diameter shaft portion, and a rolling step of rolling and molding a screw thread on the small diameter shaft portion. And include. The second pressing step is not a step of expanding the diameter over the entire length of the leg portion, but a step of obtaining a portion adjacent to the large-diameter shaft portion as a relief groove fixed to the diameter of the leg portion. That is, in the method for manufacturing a headed part disclosed in Patent Document 1, a small-diameter relief groove is formed under the neck of a large-diameter shaft portion by the second pressing step instead of the rolling step.

On the other hand, the method for manufacturing a headed part disclosed in Patent Document 2 includes a relief rolling step of forming by rolling the relief groove, and the relief rolling step includes a pair of rolling dies arranged so as to face each other. This is a step of rolling the leg portion by sliding. Further, the rolled die has a protrusion formed so as to gradually bite into the rolling leg portion, and the protrusion portion allows the surplus meat of the leg portion to be formed on the tip end side of the leg portion and a large diameter shaft. It is formed so as to flow to the part side. Further, the protruding portion is provided with an inclined wall surface that gradually guides the surplus wall that has flowed to the tip end side of the leg portion downward, and this inclined wall surface reduces the inclination angle at the end of rolling, while at the beginning of rolling. Then, the tilt angle is increased. Further, the upper surface of the protrusion is formed so as to gradually push up the surplus wall that has flowed toward the large-diameter shaft portion toward the large-diameter shaft portion, and is connected to the flat upper surface of the rolling die until the late rolling stage. It is made up of. Therefore, in the method for manufacturing a headed part disclosed in Patent Document 2, since the surplus wall that has flowed toward the tip end side of the leg is gradually guided downward, the seating surface of the large-diameter shaft portion faces the upper surface of the rolling die. Is pressed.

Japanese Unexamined Patent Publication No. 2010-42440 Japanese Patent Application Laid-Open No. 07-308727

However, in the method for manufacturing a headed part disclosed in Patent Document 1, when the diameter of the leg is expanded, a relief groove having a diameter substantially the same as the diameter obtained by the first pressing step is not constrained. The surplus thickness tends to flow in the axial direction when the diameter is expanded. As a result, there is a problem that it is difficult to determine the shape and diameter of the relief groove, and it is difficult to obtain a headed part of stable quality. On the other hand, the method for manufacturing a headed part disclosed in Patent Document 2 requires a rolling die having an upper surface and an inclined wall surface set at different angles, so that it takes time to process the rolling die. There was a problem that the manufacturing cost of the head part increased.

The method for manufacturing a headed part according to the present invention includes a pressing step of pressing a wire rod having a predetermined diameter in the axial direction to integrally mold a large diameter shaft portion having a large diameter and a small diameter shaft portion having substantially the same diameter as the wire rod. A method for manufacturing a headed part including a rolling step of rolling and molding an annular relief groove on a small-diameter shaft portion, and the rolling step is a large-diameter shaft using a surplus wall generated in the molding process of the relief groove. It is characterized in that it is a process of flowing toward a part. The rolling step is a step of forming the relief groove by sliding a pair of rolling dies, and the rolling die extrudes a surplus that gradually projects laterally so as to form the relief groove. The surplus wall extrusion portion is provided with an inclined upper surface that guides the rolling large-diameter shaft portion upward, and the inclined upper surface is provided with the surplus to the seat surface of the large-diameter shaft portion that is guided upward. It is preferably made by rolling meat. Further, the pressing step is a step of forming a concave groove on the seat surface of the large-diameter shaft portion, and the concave groove is formed so as to store the surplus wall generated in the forming process of the relief groove. Is preferable. Further, the concave groove is arranged at a connection point between the seat surface and the small diameter shaft portion, extends to a predetermined depth along the outer diameter of the small diameter shaft portion, maintains this depth, and expands to a predetermined diameter. From here, it is preferable that the material is rounded up at a predetermined angle while further expanding in the radial direction.

The method for manufacturing a headed part according to the present invention has an advantage that the material is not wasted because the surplus wall generated during the rolling process can be sent to the large-diameter shaft portion to form the large-diameter shaft portion. .. Further, the method for manufacturing a headed part according to the present invention uses a rolling die capable of forming a relief groove in the rolling step, and the rolling die transfers the excess wall to a large-diameter shaft portion. It is provided with a surplus wall extrusion portion for guiding and forming the relief groove. Therefore, not only the relief groove can be formed, but also the excess wall overhanging in the radial direction can be built up on the large-diameter shaft portion, so that there is an advantage that the strength of the large-diameter shaft portion can be increased. Further, in the method for manufacturing a headed part according to the present invention, in the pressing step, a concave groove capable of accommodating the excess wall is formed on the seat surface of the large-diameter shaft portion, so that the headed part is stretched in the radial direction in the rolling step. The extra meat to be put out can be pushed into the concave groove. Therefore, since the surplus thickness is formed as a part of the large-diameter shaft portion without protruding from the seat surface of the large-diameter shaft portion, there is no portion protruding from the seat surface in the axial direction, and problems are unlikely to occur during fastening. It also has the advantage of being able to obtain head parts. Further, in the method for manufacturing a headed part according to the present invention, a concave groove that is rounded up at a predetermined angle as the depth is increased toward the large diameter shaft portion along the outer diameter of the small diameter shaft portion and spreads in the radial direction is formed in advance. Therefore, the surplus wall guided by the concave groove can be gradually flowed from the small diameter side in the diameter increasing direction. As a result, since the build-up is performed from the small diameter side that requires mechanical strength, there is also an advantage that a flat seat surface that is strong in strength can be obtained.

It is explanatory drawing for demonstrating the pressing process of the manufacturing method of the headed part which concerns on this invention, (a) shows the state which set the wire, (b) shows the state which pressed the wire, (c). Indicates a state in which the pressed product is discharged. It is explanatory drawing for demonstrating another pressing process of the manufacturing method of a headed part which concerns on this invention, (a) shows the state which set the wire, (b) shows the state which pressed the wire. c) indicates a state in which the pressed product is discharged. It is an operation explanatory view for demonstrating the rolling process of the manufacturing method of the headed part which concerns on this invention, (a) is the plan view which shows the state which set the pressed article, (b) is A-A of (a). It is the A line enlarged sectional view. It is an operation explanatory view explaining the state which advanced the rolling from the state of FIG. 3, (a) is a plan view which shows the state at the beginning of rolling, and (b) is the enlarged sectional view taken along line BB of (a). Is. It is an operation explanatory view explaining the state which advanced the rolling from the state of FIG. 4, (a) is a plan view which shows the state of the middle stage of rolling start, (b) is the CC line enlarged sectional view of (a). Is. It is an operation explanatory view explaining the state which advanced the rolling from the state of FIG. 5, (a) is the plan view which shows the state of the late stage of rolling start, (b) is the DD line enlarged sectional view of (a). Is. It is a partial notch enlarged side view which shows the fixed die of E view of FIG. It is a cut-out enlarged sectional view of a part of a main part which shows the concave groove of the headed part which concerns on this invention.

A method for manufacturing a headed part according to the present invention will be described with reference to FIGS. 1 to 8. First, as shown in FIGS. 6A and 6B, the headed component according to the present invention includes a large-diameter shaft portion 1 having a large diameter and a small-diameter shaft that is reduced in diameter from the large-diameter shaft portion 1 and extends in the axial direction. The portion 2 is provided with a small-diameter relief groove 3 for integrally connecting the small-diameter shaft portion 2 and the large-diameter shaft portion 1.

Further, the headed component according to the present invention may be provided with the large-diameter shaft portion 1, the small-diameter shaft portion 2, and the relief groove 3, and may be a pin or rivet for fastening the members to each other, or the small-diameter shaft portion. There are various types such as bolts and tapping screws having a spiral thread (not shown) on the outer circumference of 2, or a worm gear which is a kind of gear.

The method for manufacturing a headed part according to the present invention includes a pressing step of pressing a wire rod 5 having a predetermined diameter in the axial direction, and rolling by rolling and molding an annular relief groove 3 in the pressed product 6 obtained by this pressing step. Includes steps.

In the pressing step, as shown in FIGS. 1 and 2, the wire rod 5 cut to a predetermined length is held so as to partially protrude from the receiving piece 10 (11), and is arranged to face the receiving piece 10 (11). This is a step in which the punch 15 is brought close to the receiving piece 10, the large-diameter shaft portion 1 is formed by the punch 15, the punch 15 is returned, and the pressed product 6 is discharged from the receiving piece 10 (11).

The pressed product 6 is a product before the relief groove 3 is formed, and includes a large-diameter shaft portion 1 having a flat seating surface 1b and a small-diameter shaft portion 2 having a diameter substantially equal to the diameter of the wire rod 5. .. Further, the pressed product 6 may include a concave groove 1a having a recess in the seat surface 1b as shown in FIG. 1, or does not include the concave groove 1a as shown in FIG. May be good.

As shown in FIGS. 1 (a), 1 (b) and 3 (b) or 8, the concave groove 1a of the pressed product 6 can store the surplus wall 2a generated during the rolling process described later. The dimensions are preset so that they are the same size.

The receiving piece 10 (11) is configured so that the wire rod 5 and the knockout pin 17 can be inserted through the receiving piece 10 (11), one of which is provided with an annular protrusion 10a and the other of which is provided with a flat end surface. It is configured as.

The protrusion 10a is formed so as to enter the seat surface 1b of the large-diameter shaft portion 1 and have a concave groove 1a, and has a predetermined curvature or a predetermined curvature as shown in FIGS. 1 (b), 1 (c) and 3 (b). The concave groove 1a rounded up to a predetermined angle as shown in FIG. 8 can be formed.

FIG. 8 is a concave groove 1a provided by the protrusion 10a, and the concave groove 1a enters the seat surface 1b from the small diameter shaft portion 2 toward the top of the large diameter shaft portion 1 without changing the diameter, and at a predetermined angle. It spreads in the radial direction and increases in depth, and from here, it spreads in the radial direction while maintaining the depth, and has a shape rounded up to the seat surface 1b at a predetermined angle. Therefore, the protrusion 10a has an annular structure that is raised in the opposite direction to the concave groove 1a shown in FIG.

The punch 15 is a mold that presses the wire rod 5 held by the receiving piece 10 (11) in the axial direction to plastically deform the wire rod 5 to form the large-diameter shaft portion 1, and comes into contact with the receiving piece 10 (11). It is configured to be accessible until just before the operation. Further, since the punch 15 includes a convex portion 15a having a cross shape or the like, a drive portion 1c having a cross shape or the like as shown in FIGS. 1 and 2 is formed on the top of the large diameter shaft portion 1 formed by pressing. Is configured to be transcribed.

As shown in FIG. 1A or FIG. 2A, the knockout pin 17 is always inserted through the receiving piece 10 (11) to determine the amount of protrusion of the wire rod 5 held by the receiving piece 10 (11). Consists of. Further, as shown in FIG. 1B or FIG. 2B, it is configured to withstand the pressing force generated by the approach of the punch 15, and is configured to enable plastic working of the wire rod 5.

Further, the knockout pin 17 slides so as to partially protrude from the end surface of the receiving piece 10 (11) in accordance with the return of the punch 15 shown in FIGS. 1 (c) and 2 (c), and FIG. 1 (b) ) Or the pressing product 6 shown in FIG. 2 (b) can be ejected from the receiving piece 10 (11).

The rolling step is a step of using a pair of rolling dies as shown in FIGS. 3 to 6, and is a step of finishing the headed part according to the present invention by rolling the pressed product 6 with the dies. is there.

The rolled dice are fixed dies 20 and moving dies 21 arranged at predetermined intervals, and the moving dies 21 are configured to be movable in parallel with and relative to the fixed dies 20 arranged in a fixed manner. ing. Further, as shown in FIG. 3B, the rolled die supports the pressed product 6 by slightly floating the seat surface 1b while sandwiching the small diameter shaft portion 2 of the pressed product 6 supplied to the rolled die. It is configured to do.

Further, as shown in FIGS. 3 to 6, the rolled die gradually penetrates deeply into the small diameter shaft portion 2 in the process of rolling while sandwiching the small diameter shaft portion 2, and is shown in FIG. 6 (b). The surplus wall extrusion portions 20a and 21a for forming the relief groove 3 are provided.

The surplus wall extruding portions 20a and 21a have a small pointed shape as shown in FIG. 4B at the initial stage of the start of rolling, and from earlier as shown in FIG. 5B in the middle stage of the start of rolling. It has a protruding shape with an increased thickness, and in the latter stage of the start of rolling, it has a shape that finishes the relief groove 3 as shown in FIG. 6B. Further, as shown in FIG. 7, the surplus wall extruding portion 20a (21a) has an acute-angled triangular and rectangular region, and is connected to the upper side of the rectangle and is inclined at a predetermined angle from the left end. ) Is provided.

Here, the pressing process and the rolling process for manufacturing the headed part according to the present invention will be described in order. First, a pressing process for forming the pressing product 6 from the wire rod 5 will be described with reference to FIG.

The wire rod 5 is supplied to a receiving piece 10 provided with the knockout pin 17 slidably, and is in contact with the end face of the knockout pin 17. At this time, as shown in FIG. 1A, the wire rod 5 protrudes from the receiving piece 10 by a predetermined length and is supported by the receiving piece 10.

By moving in the direction approaching the receiving piece 10, the punch 15 presses the protruding wire rod 5 in the axial direction as shown in FIG. 1 (b). As a result, the wire rod 5 is transformed into a pressed product 6 including the large-diameter shaft portion 1 having the concave groove 1a and the drive portion 1c and the small-diameter shaft portion 2.

Then, since the punch 15 starts to return to the original position, it separates from the large-diameter shaft portion 1. Further, at this time, since the knockout pin 17 slides along the moving direction of the punch 15 as shown in FIG. 1C, the pressed product 6 is discharged from the receiving piece 10.

As described above, the pressing step is a step of carrying out one cycle from the supply of the wire rod 5 to the receiving piece 10 to the ejection of the pressed product 6 by the knockout pin 17, and by repeating these steps, many pressed products are carried out. 6 is the process for obtaining. Note that FIGS. 2 (a) to 2 (c) also show the state of the pressing process similar to the above, but the difference from FIGS. 1 (a) to 1 (c) is that the pressed product 6 is pressed. A series of description will be omitted because only the point that the concave groove 10a is not provided.

Next, a rolling process of rolling and molding the relief groove 3 in the pressed product 6 will be described with reference to FIGS. 3 to 6. As shown in FIGS. 3A and 3B, when the moving die 21 is located on the right side with respect to the fixed die 20, the pressing product 6 has a small diameter shaft portion of the pressing product 6 on the side surface of the moving die 21. It is supplied to the rolling die so that 2 is pressed.

At the initial stage of rolling start shown in FIG. 4A, the moving die 21 moves from the position shown in FIG. 3A to the left side, while the fixed die 20 is fixed so as to stay in place. There is. As a result, the surplus wall extrusion portions 20a and 21a of the fixed die 20 and the moving die 21 gradually bite into the rolling small diameter shaft portion 2 and gradually become a large triangular cross section as shown in FIG. 4 (b). Therefore, a surplus wall portion 2a protruding in the radial direction is generated from the small diameter shaft portion 2.

The surplus thickness 2a is gradually increased in the middle stage of the start of rolling shown in FIG. 5, and is pressed toward the large-diameter shaft portion 1 by the inclined upper surfaces 20b and 21b that are inclined upward. As a result, the surplus wall 2a flowing to the large-diameter shaft portion 1 side enters the concave groove 1a located in the large-diameter shaft portion 1, and as can be seen from the difference between FIGS. 4 (b) and 5 (b), initially This will reduce the volume of the concave groove 1a.

Eventually, the surplus wall extruded portions 20a and 21a change from the triangular or trapezoidal shape to the square shape shown in FIG. 6B in the late stage of the rolling start shown in FIG. 6A. An annular relief groove 3 is formed between the large-diameter shaft portion 2 and the small-diameter shaft portion 2 to finish the process. Moreover, at this time, since the inclined upper surface 20b (21b) has converged on a flat surface, the surplus thickness 2a that gradually increases during this convergence is the concave groove 1a attached to the large diameter shaft portion 2. Is sent to. Therefore, in the rolling step, the area of the seat surface 1b can be made wider and flatter than that of the pressed product 6 obtained by the pressing step.

Further, if the concave groove 1a has the shape shown in FIG. 8, the excess wall 2a generated by the biting of the excess wall extrusion portions 20a and 21a easily flows from the small diameter portion to the large diameter portion of the concave groove 1a. , The concave groove can be made smaller and built up so that the diameter is gradually increased. Therefore, the seat surface 1b can be finished flat in a wide range, and the strength of the large diameter shaft portion 1 can be increased.

The headed component according to the present invention may be provided with the large-diameter shaft portion 1, the small-diameter shaft portion 2, and the relief groove 3, and may be a pin or rivet for fastening the members to each other, or the small-diameter shaft portion. There are various types such as bolts and tapping screws having a spiral thread (not shown) on the outer circumference of 2, or a worm gear which is a kind of gear.

Further, when the headed part is formed into a bolt or a tapping screw, the rolling die shall be provided with a plurality of inclined grooves (not shown) on the facing surfaces thereof, and the relief groove may be provided in the rolling step. 3 and the screw thread are formed at the same time.

1 ... Large-diameter shaft part 1a ... Concave groove 1b ... Seat surface 2 ... Small-diameter shaft part 2a ... Remaining thickness 3 ... Relief groove 5 ... Wire rod 6 ... Pressed product 10 ... Receiving piece 10a ... Protrusion 15 ... Punch 17 ... Knockout pin 20 ... Fixed dice 21 ... Moving dice

Claims (4)

A pressing process in which a wire rod having a predetermined diameter is pressed in the axial direction to integrally mold a large diameter shaft portion having a large diameter and a small diameter shaft portion having substantially the same diameter as the wire rod, and an annular relief groove is rolled and molded in the small diameter shaft portion. It is a manufacturing method of headed parts including a rolling process to be performed.
The rolling step is a method for manufacturing a headed part, which is a step of flowing a surplus wall generated in the process of forming the relief groove toward a large-diameter shaft portion. The rolling step is a step of forming the relief groove by sliding a pair of rolling dies.
The rolled die is provided with a surplus wall extrusion portion that gradually protrudes laterally so as to form the relief groove.
The surplus wall extruding portion includes an inclined upper surface that guides the rolling large-diameter shaft portion upward.
The method for manufacturing a headed part according to claim 1, wherein the inclined upper surface is formed by overlaying the surplus meat on a seat surface of a large-diameter shaft portion guided upward. The pressing step is a step of forming a concave groove on the seat surface of the large diameter shaft portion.
The method for manufacturing a headed part according to claim 1 or 2, wherein the concave groove is formed so as to accommodate the surplus wall generated in the process of forming the relief groove. The concave groove is arranged at a connection point between the seat surface and the small diameter shaft portion, extends to a predetermined depth along the outer diameter of the small diameter shaft portion, maintains this depth and expands to a predetermined diameter, and from here. The method for manufacturing a headed part according to claim 3, wherein the headed part is further expanded in the radial direction and rounded up at a predetermined angle.

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