KR102017665B1 - Method for manufacturing cotter pin shaft - Google Patents

Abstract

The present invention relates to a method for manufacturing a cotter pin shaft, which is assembled to an electric insulator, etc. of a transmission tower by a cooling firing method.
The present invention performs a process of forging a cotter pin shaft having a head portion when forming grooves and holes for guiding pins on the cotter pin shaft, and then simultaneously forging a groove at the bottom and a pair of side grooves. By implementing a new type of cold firing manufacturing method, it is possible to increase the efficiency of mold design and manufacturing, such as simplifying the structure of the mold for forming the cotter pin shaft, and to modify the cotter pin shaft during each process step. It provides a method of manufacturing a cotter pin shaft that can ensure the quality of the product, such as to completely eliminate the problem.

Description

Method for manufacturing cotter pin shaft

The present invention relates to a method for manufacturing a cotter pin shaft, and more particularly to a method for manufacturing a cotter pin shaft to be assembled to the electric insulator, etc. of the transmission tower by a cooling firing method.

Transmission towers are generally equipped with suspension insulators that support one or more transmission lines.

These insulators are insulators used to mechanically maintain or support the spirals of transmission lines or electrical equipment, and are usually manufactured in the form of a plurality of corrugations to have sufficient electrical insulation strength. .

In addition, the suspension insulator is made of an insulator such as a hard magnetic material that has excellent insulation strength and is not deteriorated and can have strong durability against environmental changes such as temperature change and sunlight.

Looking at an example of a transmission tower supporting a high-voltage transmission line and a suspension insulator installed in the transmission tower at this time, a plurality of transmission lines are installed in the transmission tower or telegraph pole through the insulator, and the insulator is installed as the distance between the transmission line and the transmission tower with insulation material. It will be kept constant, thereby preventing the high-voltage current of the transmission line is discharged through the transmission tower or telephone pole.

As described above, the insulator functions to mechanically fix the transmission line to the transmission tower, so that a significant load and tension is applied to the insulator at this time in proportion to the quantity and length of the transmission line.

In general, when assembling a cotter pin shaft for insulator assembly in a transmission tower, the cotter pin shaft assembly is difficult because an operator must work with his safety gloves removed.

In particular, since the cotter pin shaft assembly work is performed in the energized state, there are many risks, and in some cases, an electric shock accident may occur during the cotter pin shaft assembly work.

In order to improve this point, in recent years, the cotter pin shaft is assembled to the cotter pin shaft on the ground in a rotatable state, and then the cotter pin is rotated when the work is performed on the transmission tower in a high position. By handling the pin shaft, the cotter pin shaft can be easily fixed to an electric insulator tube or the like, and the cotter pin shaft assembly work is easily performed without difficulty of electric shock and without the risk of electric shock.

On the other hand, Korean Patent No. 10-1704932 discloses a "cotter pin shaft manufacturing method".

The "cotter pin shaft manufacturing method" is carried out after cutting the material to make the first groove depression in the center of the cutting portion, and to transfer based on the primary groove depression to make the second groove depression symmetrically on both sides, and then the first and second It is a manufacturing method for terminating the head of the cotter pin shaft by transferring based on the groove depression formed over the car.

However, this "cotter pin shaft manufacturing method" has the following disadvantages.

1) In order to form the second grooves at the same position after transferring the material in which the primary grooves are formed in the primary mold to the secondary mold, prevent the rotation of the material when ejecting from the primary mold relative to the primary groove. It requires mold structure to be required and means to prevent rotation in order to orient the pre-machined primary groove even when flowing into the secondary mold. There are disadvantages in terms of production costs as well as production costs.

2) After forming the secondary groove in the secondary mold, it should be equipped with a structure that prevents the rotation safely even when discharging the material from the secondary mold, which causes a decrease in productivity during the manufacture of the mold and the mold setup.

3) After finishing the formation of the first and second grooves, it is necessary to prevent rotation during transportation to form the head portion of the cotter pin shaft, and the lower grooves formed even when entering the tertiary mold for forming the head portion. And a support mold corresponding to a pair of side grooves which are secondly processed so that the pair of side grooves are not deformed, and the support mold has a structure that is difficult to withstand the forging pressure required for forming the head portion of the cotter pin shaft. As a result, the production of molds, the lifespan of the molds, and the conditions for installing the molds act as factors that hinder productivity and added value.

Korean Patent Registration No. 10-1704932

Accordingly, the present invention has been made in view of the above, and when forming grooves and holes for guiding the pins on the cotter pin shaft, performing a process of forging a cotter pin shaft having a head portion, and then forming a groove and a lower groove. Implementing a new form of cold-fired manufacturing that performs the process of forging a pair of side grooves at the same time, the efficiency of the mold design and fabrication can be increased by simplifying the mold structure for forming the cotter pin shaft. It is an object of the present invention to provide a method for manufacturing a cotter pin shaft that can ensure the quality of a product, such as to completely eliminate problems such as deformation of the cotter pin shaft during each process step.

In order to achieve the above object, the manufacturing method of the cotter pin shaft provided in the present invention has the following characteristics.

The method of manufacturing the cotter pin shaft includes a first step of cutting the round bar material for molding the cotter pin shaft to a predetermined length, and forming the head portion through forging molding in the primary forging die to the material cut in the first step And a third step of simultaneously molding the bottom groove and the pair of side grooves by extrusion molding in the extrusion mold on the material in which the head part is molded in the second step, and the bottom groove and the side surface in the third step. The fourth step of forming a hole penetrating a pair of side grooves through a drill process on the material after the groove forming.

Here, the first step may further include a first-first step of forming the material chamfering through the forging molding in the secondary forging die at the edge edge of the cutting portion of the material.

The fourth step further includes a step 4-1 of forming a groove chamfer through extrusion molding in a die mold for chamfering at a sharp corner of a connection portion between grooves after forming a lower groove and a pair of side grooves. can do.

In step 4-1, the die mold for chamfering, which is seated on the groove when forming the groove chamfer, may include a guide taper of guide shape.

The method of manufacturing the cotter pin shaft provided by the present invention is a coater by applying a method of forging a cotter pin shaft having a head portion and a step of simultaneously forging a groove at the bottom and a pair of side grooves at the same time. It can improve the efficiency of mold design and manufacturing by simplifying the structure of mold for forming pin shaft, and can completely eliminate problems such as cotter pin shaft deformation during each process step. There is an effect to ensure the quality of.

For example, 1) The primary material chamfering molding process and the secondary head molding process for the material can be carried out in accordance with the general cold forging molding die and sequence, so that it can be used without changing the structure of the existing mold or improving the structure. It is easy to design and manufacture mold, and also easy to install.

2) The grooves for guiding the fixing pins are manufactured by installing a structure that minimizes the deformation of the cotter pin shaft by applying the simultaneous extrusion plastic processing method. There is no problem in manufacturing.

3) It is not necessary to prevent the rotation during transportation to form the cotter pin head part. When forming the fixing pin guide groove, the bottom center and side symmetric grooves are simultaneously formed by cold plastic deformation method, thereby deforming the deformation. There is no need to install the support type separately.

4) The guide structure can be visually checked on the front surface even when the groove is smoothly curved at the corners generated after cold plastic molding, and the groove is formed by applying a guide tapered guide structure so that the guide is securely seated on the groove. It can be safely seated and molded.

1 is a process chart showing a manufacturing method of a cotter pin shaft according to an embodiment of the present invention
2 is a cross-sectional view showing an extrusion die for forming a groove used in a method for manufacturing a cotter pin shaft according to an embodiment of the present invention.
Figure 3a and Figure 3b is a cross-sectional view showing the extrusion die for groove chamfering molding used in the manufacturing method of the cotter pin shaft according to an embodiment of the present invention.
4 and 5 are a perspective view showing a cotter pin shaft manufactured by a method for manufacturing a cotter pin shaft according to an embodiment of the present invention

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a process chart showing a manufacturing method of a cotter pin shaft according to an embodiment of the present invention.

As shown in Figure 1, the manufacturing method of the cotter pin shaft is formed by forming the head and the material chamfer for the material through the cold forging molding method, and then the groove and the bottom groove for the material through the cold extrusion molding method After forming a pair of side grooves and forming a groove chamfer, the drill is then continuously formed to form a hole for joining a fixing pin. Accordingly, the design and structure of a mold for forming a cotter pin shaft are determined. It can simplify and ensure the quality of the molded article.

First, as a first step, a step of cutting the material of the round bar for forming the cotter pin shaft to a predetermined length.

Here, the material 10 is a round bar material of a metal material, it is cut using a conventional cutter (not shown) in a dimension that meets the design specifications.

Next, as a step 1-1, after cutting the material in the first step, the step of forming the material chamfer 11 in the edge edge of the material cutting portion is carried out.

That is, after cutting the material 10 in the first step, the material 10 is transferred to a secondary forging die (not shown), and then the forging around the edge of the material cutting surface to form the material chamfered portion 11. do.

Next, as a second step, a step of forming the head portion 12 through the forging molding in the primary forging die to the material cut in the first step.

That is, the material 10, which has undergone the first step and the first-first step, for example, has a predetermined length, and the material 10 having the material chamfered portion 11 formed on the cutting portion is formed by a primary forging die ( After injection into the mold, the head portion 12 is formed at one end of the raw material through cold forging.

At this time, the step of forming the material chamfer (11) and the head portion 12 in the step 1-1 is to be carried out as a linking process in one cold forging facility belonging to the secondary forging die and the primary forging die. Can be.

Thus, the material chamfering 11 and the head 12 are formed in a general cold forging molding sequence, and can be carried out using a conventional cold forging facility as it is, so that grooves requiring a change in the mold structure as before are required. Compared to the method of forming the head part after molding, there is an advantage in terms of mold design and structure.

Next, as a third step, the bottom groove 13 and the pair of side grooves 14a and 14b are extruded from the extrusion die for groove molding to the material 10 having finished molding the head part 12 in the second step. Simultaneously molding.

That is, after the raw material chamfered part 11 forming step and the head part 12 forming step is finished, the raw material 10 is injected into the groove forming extrusion die. The lower groove 13 and the pair of side grooves 14a and 14b having a "U" shape are formed.

In the third step, when the lower groove 13 and the pair of side grooves 14a and 14b are formed, an extrusion plastic working method using a die molding for groove molding is applied, which minimizes material deformation and simultaneously forms grooves. Therefore, there is no need to provide a separate device such as a support mold for preventing rotation or deformation in order to prevent the groove forming direction from being misaligned during feeding and discharging or transferring in the mold, and thus, the overall installation The structure can be simplified.

Looking at the process of performing the groove forming step in the third step by using the groove forming extrusion die 100 as follows.

2 is a cross-sectional view showing an extrusion die for forming a groove used in a method for manufacturing a cotter pin shaft according to an embodiment of the present invention.

As shown in FIG. 2, the groove forming extrusion die 100 has a cylindrical housing die 110 and a coaxial structure inside the housing die 110, and is sequentially inserted and assembled from the front end to the rear end. The first die 120, the second die 130, the third die 140, and the fourth die 150 are included.

The first core 160 is inserted and assembled on the axis of the first die 120, and the second core 170 is inserted and assembled on the axis of the second die 130, and the second core 170 is inserted and assembled. On the inner axis of the third core 180 is inserted and assembled.

In particular, side groove forming protrusions 190a for extruding the side grooves 14a and 14b are formed on both sidewalls of the inner circumferential surface of the second core 170, respectively, and at the same time, the third core 180 is formed. At the front surface of the bottom), a lower groove forming protrusion 190b for extruding the lower groove 13 is formed.

At this time, the side groove forming protrusion 190a and the lower groove forming protrusion 190b may form a shape that is formed in a “U” shape.

Accordingly, the material 10 having finished the head portion 12 forming step is fed into the groove forming extrusion die 100 by transfer (not shown) or the like, and then the material 10 is pressed by the press pressure on the punch die (not shown) side. The pair of side grooves 14a and 14b and the bottom groove 13 are simultaneously extruded by the side groove forming protrusion 190a and the bottom groove forming protrusion 190b on both side portions and the bottom of the bottom side.

At this time, since the injection direction of the material does not need to match the direction of the material injection into the groove forming extrusion die 100 side, it does not require a means such as a separate rotation preventing device.

Next, in step 3-1, after forming the lower groove 13 and the pair of side grooves 14a and 14b in the third step, the grooves are formed in the compression die for chamfering at the sharp corners of the joints between the grooves. The step of forming the groove chamfer 18 through plastic deformation is carried out.

In step 3-1, the groove chamfer may be formed after guiding the material input through the tapered structure of the groove guide protrusion that is seated on the material side groove when forming the groove chamfer.

Looking at the process of performing the groove forming step in the step 3-1 using the groove forming extrusion die 100 as follows.

3A and 3B are cross-sectional views, front views, and enlarged views illustrating extrusion dies for groove chamfering moldings used in the method for manufacturing a cotter pin shaft according to an embodiment of the present invention.

As shown in FIGS. 3A and 3B, the groove die extrusion molding 200 has a cylindrical housing die 210 and a coaxial structure inside the housing die 210 and sequentially from the front end to the rear end. The first die 220, the second die 230, the third die 240 and the fourth die 250 are inserted into the assembly.

The first core 260 is inserted and assembled on the axis of the first die 220, and the second core 270 is inserted and assembled on the inner axis of the first core 260.

In particular, side groove guide protrusions 280a for guiding the side grooves 14a and 14b are formed on both sidewalls of the inner circumferential surface of the first core 260, respectively, and at the same time, the second core 270 is formed. The front surface of the lower groove guide protrusion 280b for guiding the lower groove 13 is formed.

At this time, the side groove guide protrusion 280a and the bottom groove guide protrusion 280b may form a shape that is formed in a “U” shape.

In particular, groove chamfer forming round parts 290a are formed at each boundary between the side groove guide protrusions 280a and the lower groove guide protrusions 280b.

Then, the periphery of the material insertion hole 300 including the periphery of the front end portion of the both side groove guide protrusions 280a, that is, the periphery of the initial insertion portion of the material insertion hole 300 into which the material 10 enters the entire circumference. The tapered portion 290b is formed to form an inclination of about 45 ° over, so that the material side side grooves 14a and 14b are guided by the tapered portion 290b when entering the material into the first core 260. Of course, the lower groove 13 is not damaged.

Therefore, the material 10 of the side grooves 14a and 14b and the lower groove 13 forming step in the third step is inserted into the material insertion hole of the extrusion die 200 for groove chamfering by transfer (not shown). When the material 10 is pressed by the press pressure on the punch die (not shown) side after being introduced to the taper portion 290b while being guided, the side groove guide protrusion 280a and the bottom groove guide protrusion ( 280b is pressed by the groove chamfer forming round portion 290a at the boundary between the side grooves 14a and 14b and the lower edges of the sharp corners at the boundary 14, and thus the pressed portion, That is, the groove chamfer 18 is formed at the boundary between the side grooves 14a and 14b and the lower groove 14.

Next, as a fourth step, the pair of side grooves 14a and 14b are drilled in the radial direction of the material by drilling into the material 10 having finished forming the lower groove 13 and the side grooves 14a and 14b in the third step. A step of forming the hole 15 penetrating along is performed.

4 and 5 are a perspective view showing a cotter pin shaft manufactured by a method for manufacturing a cotter pin shaft according to an embodiment of the present invention.

As shown in Figures 4 and 5, the cotter pin shaft 16 includes a body portion 17 in the form of a circular bar, the head portion 12 is formed at the upper end of the body portion 17 At the lower end, a lower groove 13 on the bottom and a pair of side grooves 14a and 14b on both sides are formed.

At this time, the lower groove 13 and the side grooves 14a and 14b are formed in succession to form a "U" shape.

In addition, a material chamfer 11 is formed around the bottom edge of the body portion 17, and groove chamfers 18 are formed at each boundary between the bottom groove 13 and the side grooves 14a and 14b. .

In addition, the body portion 17 is formed with a hole 15 having a structure horizontally penetrating radially through the side grooves (14a, 14b) on both sides, the hole 15 at this time is a known fixing pin (not shown) Si) can be combined in a fitted form.

Therefore, after assembling the fixed pin in the form of wire to the cotter pin shaft 16 in a rotatable state, by handling the cotter pin shaft in a manner of rotating the fixed pin in the form of wire when working on the transmission tower in a high position When the cotter pin shaft is assembled to the insulator tube, it can be easily fixed without the risk of electric shock.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

10: material
11: material chamfering
12: head part
13: bottom groove
14a, 14b: side groove
15: hall
16: cotter pin shaft
17 body
18 groove groove

Claims (4)

A first step of cutting the round bar material for forming the cotter pin shaft to a predetermined length;
Step 1-1 to form the material chamfering through the forging molding in the secondary forging mold in the edge edge of the cutting portion of the material in the first step;
A second step of forming a head part through forging molding in a first forging die on the material cut in the first step;
A third step of simultaneously molding the bottom groove and the pair of side grooves by the side groove forming protrusion and the bottom groove forming protrusion through extrusion molding in the groove forming extrusion die on the material in which the head part is molded in the second step; ;
Forming a groove chamfer through the plastic deformation in the compression die for groove chamfering at a sharp corner of the pair of side grooves in the third step;
A fourth step of forming a hole penetrating a pair of side grooves by drilling into a material in which the bottom groove and the side groove forming are finished in the third step, and the groove chamfer is formed in the step 3-1;
Including,
The groove chamfering extrusion die includes a cylindrical housing die and a first die, a second die, a third die, and a fourth die which are coaxially structured inside the housing die and sequentially inserted into and assembled from the front end portion to the rear end portion. At the same time, the first core is inserted and assembled on the axis of the first die, the second core is inserted and assembled on the inner axis of the first core,
Side groove guide protrusions for guiding the side grooves are formed on both side walls of the inner circumferential surface of the first core, and lower groove guide protrusions for guiding the lower grooves are formed on the front surface of the second core. In addition, the side groove guide protrusion and the bottom groove guide protrusion can be formed to form a "U" shape,
Each boundary between the side groove guide protrusions and the lower groove guide protrusions on both sides is formed with grooves for forming the groove chamfer, respectively, and at the periphery of the material insertion hole including the periphery of the tip end of the side groove guide protrusions on both sides. As the tapered portion is formed to have an inclination of about 45 ° over the entire circumference, the tapered portion is guided by the tapered portion when the material enters the inside of the first core, and thus the side groove and the lower groove are not damaged.
When the material having finished the side groove and the bottom groove forming step in the third step is introduced into the material insertion hole of the extrusion die for groove chamfering by the transfer or the like while receiving the taper part, the material is pressurized by the press pressure on the punch mold side. The edge between the side groove and the bottom groove is pushed by the round groove for forming the groove chamfer at the boundary between the side groove guide protrusion and the bottom groove guide protrusion. Groove chamfered portion is molded in the site, characterized in that the manufacturing method of the cotter pin shaft. delete delete delete

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