KR20240007952A - A rolling device for electrical contact equipped with a rounding recess and an electrical contact manufacturing apparatus including the same - Google Patents

Abstract

An example is a rolling device for electrical contacts and an electrical contact manufacturing device including the same.
A rolling device for electrical contacts according to an embodiment includes a cylindrical rolling body, a rounding recess rolling portion disposed on the outer periphery of the rolling body, a fastening through hole penetrating the central axis of the rolling body, and a fastening through hole in the fastening through hole. It may include a fastening groove extending inside the rolling body.

Description

A rolling device for electrical contact equipped with a rounding recess and an electrical contact manufacturing apparatus including the same}

The embodiment relates to a rolling device for electrical contacts and an electrical contact manufacturing device including the same.

Electrical contact materials are electrical contact elements that mechanically open and close electrical circuits or make contact, and are widely used in various industries such as electricity, electronics, communications, automobiles, and elevators, including various switches, relays, and electronic gates.

The required performance of electrical contacts requires low contact resistance, high electrical conductivity, thermal conductivity, and stability, excellent wear resistance, and low deformation of the contact surface.

Although the performance of these electrical contacts is determined by the components of the electrical contacts, minimizing surface defects or contaminants that may occur during the manufacturing process of the electrical contacts is very important in determining the performance of the electrical contacts.

Meanwhile, electrical contact materials of various materials are used in electrical products depending on the usage environment, and are manufactured using melting or powder metallurgy methods depending on the manufacturing method.

For example, electrical contacts manufactured by melting methods include Ag-Cu-based, Ag-CdO-based, or Ag-SnO _2- based, and electrical contacts manufactured by powder metallurgy methods include Cu-W-based, Ag-W-based, and Ag-based. -WC-based, Ag-C-based, Ag-Ni-based, etc.

According to the applicant's internal technology, AgCu electrical contact material is a contact material suitable for continuous casting rather than extrusion, and is manufactured through gravity continuous casting.

For example, according to internal technology, manufacturing processes for Ag-Cu contact materials or precious metal materials include melting, continuous casting, wire drawing, and cutting.

However, the surface quality is poor, such as gear marks due to knurling on the solid billet made by continuous casting of Ag-Cu contact material, or peeling on the surface of the cut product after drawing, so it is used as an electrical contact or precious metal material. There is a problem in that performance or quality deteriorates.

Specifically, Figure 1 is a photograph of the Ag-Cu contact material casting state in a continuous casting process according to internal technology.

According to internal technology, in the continuous casting process of molten metal, the solidified solid billet (BS) is pulled out using a predetermined transfer roll (not shown) using a fine pressing force or tension.

However, according to internal technology, knurling (not shown) in a predetermined inclined sawtooth shape is performed on the contact surface of the transfer roll in order to increase the drawing tension or friction. This knurling is performed on the surface of the solid billet (BS). Surface dents such as tooth marks (BD) corresponding to the knurling pattern occur.

Meanwhile, for process efficiency, downward tension must be applied to move the solid billet (BS) downward through the transfer roll, and in order to increase downward tension, it is necessary to increase friction through knurling.

However, such knurling causes surface indentations such as tooth marks (BD) on the surface of the solid billet (BS), and these tooth marks (BD) are a technical contradiction that deteriorates the performance or surface quality as an electrical contact or precious metal material. are facing.

Also, Figure 2 is a photograph of a wire (W1) drawn of Ag-Cu-based contact material according to internal technology.

According to internal technology, as shown in FIG. 2, surface peeling (W1D) occurs in the drawn wire (W1) of Ag-Cu contact material, resulting in a decrease in surface quality, resulting in a decrease in performance or quality as an electrical contact or precious metal material. There is.

This surface peeling (W1D) of the drawn wire is caused by tooth marks (BD) on the solid billet (BS) due to the knurling described above or by surface oxidation of the drawn wire.

One of the technical tasks of the embodiment is rolling for electrical contacts that prevents surface dents from occurring on the surface of the solid billet (BS) while applying appropriate tension to the solid billet (BS) in Ag-Cu-based contact materials or precious metal materials. The purpose is to provide a device and an electrical contact manufacturing device including the same.

In addition, one of the technical challenges of the embodiment is to solve the problem of deterioration in performance or quality as an electrical contact or precious metal material due to poor surface quality, such as skin, on the surface of the cut product after drawing the Ag-Cu contact material or precious metal material. .

The technical problems of the embodiments are not limited to those described in this item and include those that can be understood throughout the specification.

According to an embodiment, a rolling device for electrical contacts includes a cylindrical rolling body, a rounding recess rolling portion disposed on the outer periphery of the rolling body, a fastening through hole penetrating the central axis of the rolling body, and the fastening through hole. It may include a fastening groove extending inside the rolling body.

The rounding recess rolling part may be disposed on the outer periphery of the rolling body along an axis perpendicular to the central axis of the rolling body.

The rounding recess rolling part may include a first rounding recess surface portion disposed in a first area of the outer periphery of the rolling body and a first rounding recess pattern portion disposed in a second area of the outer periphery of the rolling body. .

The first rounding recess pattern portion may be disposed on an axis perpendicular to the central axis of the rolling body.

The embodiment may further include a second rolling body having a predetermined second rounding recess rolling part at a position corresponding to the rounding recess rolling part.

The second rounding recess rolling part of the second rolling body may include a second rounding recess surface portion in a first area and a second rounding recess pattern portion in a second area of the outer peripheral surface of the second rolling body.

The second rounding recess rolling part of the second rolling body may include a third rounding recess pattern part in a third area of the outer peripheral surface of the second rolling body.

The second rounding recess pattern portion may not be disposed on an axis perpendicular to the central axis of the rolling body.

The third rounding recess pattern portion may not be disposed on an axis perpendicular to the central axis of the rolling body.

The first rounding recess pattern portion may not overlap top and bottom with the second rounding recess pattern portion or the third rounding recess pattern portion.

The electrical contact manufacturing device according to the embodiment includes a rolling device for electrical contacts of any one of claims 1 to 9 that draws a billet cast from a predetermined molten metal, and an electrical contact device that cuts the surface of the wire from which the billet is drawn. It may include a shaving die.

The shaving dice for electrical contacts include a dice bearing portion; and a die cutting unit having a cutting hole in the center.

The die bearing unit includes a bearing body, a bearing inclined protrusion protruding from a first side of the bearing body toward the die cutting portion, and a bearing recess disposed on a second side opposite to the first side of the bearing body. It can be included.

According to the rolling device for electrical contacts and the electrical contact manufacturing device including the same according to the embodiment, the rolling device for electrical contacts having a rounding recess structure provides high downward pressure on a solid billet of Ag-Cu contact material or precious metal material. It has the technical effect of providing electrical contacts or precious metal materials with excellent surface quality by improving process efficiency by applying tension and at the same time preventing surface dents such as tooth marks on the surface of the solid billet.

In addition, according to an example, in Ag-Cu-based contact materials or precious metal materials, the surface shell of the electrical contact material or precious metal material is removed by the shaving die, and the electrical conductivity or glossiness is improved, thereby significantly improving the characteristics of the electrical contact material or precious metal material. There is an improved technical effect.

The technical effects of the embodiments are not limited to those described in this item and include those that can be understood throughout the specification.

Figure 1 is a photograph of the Ag-Cu contact material casting state according to internal technology.
Figure 2 is a photograph of a drawn wire (W1) of Ag-Cu-based contact material according to internal technology.
Figure 3a is a front view of a rolling device 200 for electrical contacts according to an embodiment.
FIG. 3B is a right side view of the rolling device 200 for electrical contacts according to the embodiment shown in FIG. 3A.
Figure 4 is a front photograph of the rolling device 200 for electrical contacts according to an embodiment.
FIG. 5 is a cross-sectional view taken along line B1-B1' of the rolling device 200 for electrical contacts according to the embodiment shown in FIG. 4.
6 and 7 are illustrations of a rolling process using a first electrical contact rolling device 200A and a second electrical contact rolling device 200B.
8 is an exemplary rolling process using a first electrical contact rolling device 200A and a second electrical contact rolling device 200B as an additional embodiment.
Figure 9 is a perspective view of a shaving die 300 for electrical contacts or precious metals according to an embodiment.

Hereinafter, the invention according to an embodiment for solving the above problems will be described in more detail with reference to the drawings.

The suffixes “module” and “part” for components used in the following description are simply given in consideration of the ease of writing this specification, and do not in themselves give any particularly important meaning or role. Accordingly, the terms “module” and “unit” may be used interchangeably.

Terms containing ordinal numbers, such as first, second, etc., may be used to describe various components, but the components are not limited by the terms. The above terms are used only for the purpose of distinguishing one component from another.

Singular expressions include plural expressions unless the context clearly dictates otherwise.

In this application, terms such as “comprise,” “have,” or “comprise,” are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification. It should be understood that it does not exclude in advance the presence or addition of other features, numbers, steps, operations, components, parts, or combinations thereof.

(Example)

As described above, according to the applicant's internal technology, processes such as melting, continuous casting, wire drawing, and cutting are being carried out as manufacturing processes for Ag-Cu-based contact materials or precious metal materials. At this time, approximately 7 to 20% Cu may be included depending on the Ag-Cu composition ratio. Additionally, a small amount of P can be added for deoxidation.

In the embodiment, melting may be performed using a high-frequency induction melting furnace or a vacuum melting furnace, but is not limited thereto.

In the embodiment, the continuous casting machine used in continuous casting may be curved, vertically curved, horizontal, etc., but is not limited thereto.

Hereinafter, the rolling device according to the embodiment will be described focusing on the case where it is applied to products for electrical contacts, but the rolling device according to the embodiment can also be applied to products for precious metals.

FIG. 3A is a front view of the rolling device 200 for electrical contacts according to an embodiment, and FIG. 3B is a right side view of the rolling device 200 for electrical contacts according to the embodiment shown in FIG. 3A.

Referring to FIGS. 3A and 3B , the rolling device 200 for electrical contacts according to the embodiment may include a rolling body 210, a fastening through hole 212, and a fastening groove 213.

Specifically, the rolling device 200 for electrical contacts according to the embodiment includes a cylindrical rolling body 210, a rounding recess rolling portion 210R disposed on the outer periphery of the rolling body 210, and the rolling body ( It may include a fastening through-hole 212 penetrating the center of the fastening hole 210, and a fastening groove 213 extending from the fastening through-hole 212 to the inside of the rolling body 210.

A drive shaft (not shown) of a predetermined drive motor may be inserted into the fastening through hole 212, and a fastening portion (not shown) of the drive shaft may be fastened to the fastening groove 213 to transmit rotational driving force. there is.

According to internal technology, in the continuous casting process of molten metal, drawing can be carried out by downward tension through a solidified solid billet (BN) (see FIG. 7) between a pair of rolling devices 200 for electrical contacts.

The solid billet (BS) may be located between the rounding recess rolling portions (210R) of a pair of electrical contact rolling devices 200, and the outer peripheral surface of the solid billet (BS) is a pair of rounding recess rolling. It can be accessed from section 210R.

According to the rolling device for electrical contacts according to the embodiment, a high downward tension is applied to a solid billet of Ag-Cu-based contact material or precious metal material by the rolling device for electrical contacts provided with a rounding recess rolling part (210R), and the process is carried out. It has the technical effect of providing electrical contacts or precious metal materials with excellent surface quality by improving efficiency and preventing surface dents such as gear marks on the surface of the solid billet.

Hereinafter, technical features of the rolling device 200 for electrical contacts according to an embodiment will be described in more detail with reference to FIGS. 4 to 8.

FIG. 4 is a front photograph of the rolling device 200 for electrical contacts according to an embodiment, and FIG. 5 is a cross-sectional view taken along line B1-B1' of the rolling device 200 for electrical contacts according to the embodiment shown in FIG. 4. .

Referring to FIGS. 4 and 5, the rolling device 200 for electrical contacts according to the embodiment includes a cylindrical rolling body 210 and a rounding recess rolling portion 210R disposed on the outer periphery of the rolling body 210. ) and a fastening through hole 212 penetrating the central axis (X) of the rolling body 210.

The rounding recess rolling part 210R may be arranged along an axis (Y) perpendicular to the central axis (X) of the rolling body 210. For example, the rounded recess rolling part 210R may be disposed along the outer peripheral surface of the rolling body 210 on an axis (Y) perpendicular to the central axis (X) of the rolling body 210.

Next, FIGS. 6 and 7 are illustrations of a rolling process for a solid billet (BN) using the first electrical contact rolling device 200A and the second electrical contact rolling device 200B. The solid billet (BN) can be moved in a direction perpendicular to the XY plane (Z-axis).

According to an embodiment, the solid phase solidified between a pair of electrical contact rolling devices, for example, a first electrical contact rolling device 200A and a second electrical contact rolling device 200B, in the continuous casting process of molten metal. Drawing may proceed by downward tension through the billet (BN) (see FIG. 7).

The solid billet (BN) may be located between the rounding recess rolling portions of a pair of electrical contact rolling devices, and the outer peripheral surface of the solid billet (BS) may be in contact with the pair of rounding recess rolling portions.

For example, according to the embodiment, the solid billet (BN) is formed by the first rounding recess rolling part 200R1 of the first electrical contact rolling device 200A and the second rounding of the second electrical contact rolling device 200B. It is located between the recess rolling portions 200R2, and the outer peripheral surface of the solid billet BN may be in contact with the pair of rounded recess rolling portions.

In the internal technology, when the rounding recess rolling part is not adopted, the solid billet and the transfer roll are in line contact and the contact area is narrow, so the friction force is low. Knurling is performed considering the narrow contact area to increase the friction force.

However, although the tension is increased by knurling, there is a technical problem in that the tension is concentrated on the contact surface between the solid billet and the transfer roll, causing surface pitting on the surface of the solid billet as the average pressure increases.

According to the embodiment, the outer peripheral surface of the solid billet BN is aligned with the first rounding recess rolling portion 200R1 of the first electrical contact rolling device 200A and the second rounding recess rolling portion 200R1 of the second electrical contact rolling device 200B. As the surface area located between the recess rolling parts (200R2) and in contact with the rounding recess rolling part is significantly expanded, the tension can increase, and as the average pressure applied to the contact point is distributed, surface defects appear on the surface of the solid billet (BN). There is a special technical effect that does not cause

Accordingly, according to the rolling device for electrical contacts according to the embodiment, the rolling device for electrical contacts having a rounding recess structure, for example, a rounding recess rolling part, is applied to a solid billet of Ag-Cu contact material or precious metal material. It has the technical effect of providing electrical contacts or precious metal materials with excellent surface quality by improving process efficiency by applying high downward tension and at the same time preventing surface dents such as tooth marks on the surface of the solid billet.

Next, FIG. 8 is an exemplary diagram of a rolling process using the first electrical contact rolling device 200A and the second electrical contact rolling device 200B as an additional embodiment.

Referring to FIG. 8, the first electrical contact rolling device 200A may include a first rounding recess rolling part 200R1.

At this time, the first rounding recess rolling part 200R1 may include a first rounding recess surface part 200R1a and a first rounding recess pattern part 200R1b.

The first rounding recess surface portion 200R1a may be a smooth surface without a predetermined knurling pattern, and the first rounding recess pattern portion 200R1b may be a rough surface with a predetermined knurling pattern.

The first rounding recess pattern portion 200R1b may be disposed on the Y-axis perpendicular to the X-axis.

Additionally, the second electrical contact rolling device 200B may include a second rounding recess rolling portion 200R2.

The second rounding recess rolling part 200R2 may include a second rounding recess surface part 200R2a and a second rounding recess pattern part 200R2b. Additionally, the second rounding recess rolling part 200R2 may include a third rounding recess pattern part 200R2c.

The second rounding recess surface portion 200R2a may be a smooth surface without a predetermined knurling pattern, and the second rounding recess pattern portion 200R2b and the third rounding recess pattern portion 200R2c may have a predetermined knurling pattern. It may be a rough surface with .

The second rounded recess pattern portion 200R2b may be disposed on the Y1 axis, which is not perpendicular to the X axis. Additionally, the third rounded recess pattern portion 200R2c may be disposed on the Y3 axis, which is not perpendicular to the X axis.

According to a further embodiment, the first rounding recess pattern portion 200R1b may not vertically overlap the second rounding recess pattern portion 200R2b.

Additionally, according to an additional embodiment, the first rounding recess pattern portion 200R1b may not vertically overlap the third rounding recess pattern portion 200R2c.

According to the embodiment, the first rounding recess pattern portion 200R1b is disposed at a position that does not vertically overlap the second rounding recess pattern portion 200R2b or the third rounding recess pattern portion 200R2c, thereby 1 By avoiding overlap of the rounding recess pattern portion in the Y-axis direction where the strongest pressure is applied in the rounding recess rolling portion (200R1) and the second rounding recess rolling portion (200R2), intensive line pressure applied to the billet is reduced. It can be prevented.

In addition, according to a further embodiment, the contact area with the billet is maximized by the first rounding recess surface portion 200R1a and the second rounding recess surface portion 200R2a, and the first to third rounding recess pattern portions are formed in a triangular shape. By arranging (200R1b 200R2b, 200R2c), there is a special technical effect that can maximize the downward pulling tension.

Next, Figure 9 is a perspective view of a shaving die 300 for electrical contacts or precious metals according to an embodiment.

In the following embodiments, the shaving dice 300 according to the embodiment will be described focusing on the case where it is applied to electrical contacts, but the shaving die 300 according to the embodiment can also be applied to shaving dice for precious metals.

One of the technical challenges of the embodiment is to solve the problem of poor surface quality, such as peeling on the surface of the cut product after drawing, in Ag-Cu-based contact materials or precious metal materials, which deteriorates the properties as electrical contact or precious metal materials. It is intended to be done.

Referring to FIG. 9, the shaving die 300 for an electrical contact according to an embodiment may include a dice bearing portion 310 and a dice cutting portion 320.

For example, the shaving die 300 for an electrical contact according to an embodiment may include a die bearing unit 310 and a die cutting unit 320 having a cutting hole 320C at the center.

The dice bearing unit 310 includes a bearing body 311, a bearing inclined protrusion 312 protruding from a first side of the bearing body 311 toward the dice cutting unit 320, and the bearing body 311. ) may include a bearing recess (310R) disposed on the second side, which is the opposite side of the first side.

The bearing body 311 and the bearing inclined protrusion 312 may be formed integrally, but are not limited thereto. The dice bearing unit 310 may be made of a metal material such as iron.

In addition, the die cutting part 320 has a cutting body 321 coupled to the bearing body 311, and extends from the cutting body 321 in a direction away from the first side of the bearing body 311 and protrudes. It may include a cutting blade portion 322 and a cutting hole 320C disposed at the center of the cutting blade portion 322.

The cutting body 321 and the cutting blade portion 322 may be formed integrally, but are not limited thereto.

The die cutting portion 320 may be formed of cemented carbide or artificial diamond, but is not limited thereto. For example, the material of the die cutting part 320 may be a WC-Co-based, WC-TiC-TaC-Co-based, or WC-TiC-Co-based sintered alloy, but is not limited thereto. The die cutting portion 320 can be firmly coupled to the bearing body 311 in the form of a shrink fit after heating the bearing body 311.

In the embodiment, the die bearing unit 310 includes a bearing inclined protrusion 312 protruding from the first side of the bearing body 311 in the direction of the die cutting unit 320, so that the die cutting unit 320 is connected to the bearing body. (311) By protruding from the surface, the surface cutting process of the electrical contact material can be precisely observed, enabling a precise surface cutting process, which has the technical effect of providing high-quality contact materials or precious metal materials.

Meanwhile, according to internal technology, the problem that cutting foreign matter discharged while cutting the cutting object can fill the cutting hole was studied. Accordingly, according to the embodiment, the die bearing portion 310 includes a bearing inclined protrusion 312 protruding from the first side of the bearing body 311 toward the die cutting portion 320, thereby forming a surface of the electrical contact material. Foreign matter cut from can be spaced apart from the cutting blade portion 322 and the cutting hole 320C disposed in the center of the cutting blade portion 322. This has the technical effect of allowing cutting to proceed with precision by preventing cutting foreign matter from filling the cutting hole 320C and keeping it spaced apart from the cutting blade portion 322.

The dice bearing unit 310 includes a bearing body 311, a bearing inclined protrusion 312 protruding from a first side of the bearing body 311 toward the dice cutting unit 320, and a bearing body 311. It may include a bearing recess 310R disposed on the second side, which is the opposite side of the first side.

In addition, the die cutting unit 320 includes a cutting body 321, a cutting blade portion 322 extending from the cutting body 321 and protruding in the first side direction of the bearing body 311, and the cutting blade portion. (322) It may include a cutting hole 320C disposed at the center, the cutting blade portion 322, and a cutting penetration portion 320T penetrating the cutting body 321.

The diameter D of the cutting through portion 320T of the die cutting portion 320 may gradually increase from the first side to the second side of the bearing body 311.

According to an embodiment, as the diameter D of the cutting through portion 320T of the die cutting portion 320 gradually increases from the first side to the second side of the bearing body 311, the cut contact material The efficiency of the cutting process can be increased by smooth discharge movement, and there is a technical effect of maintaining high quality of the contact material by preventing contact between the already cut contact material and the die cutting part 320.

In the embodiment, the die cutting portion 320 includes a cutting blade portion 322 that extends and protrudes from the cutting body 321 in a direction away from the first side direction of the bearing body 311 and the cutting blade portion 322. It may include a cutting hole 320C disposed in the center.

For example, the die cutting part 320 may include a cutting blade part 322 that extends and protrudes from the cutting body 321 in a direction away from the bearing inclined protrusion 312.

The die cutting part 320 of the embodiment includes a cutting blade part 322 that extends and protrudes from the cutting body 321 in a direction away from the bearing inclined protrusion 312, so that the surface cutting process of the electrical contact material can be performed more precisely. There is a special technical effect that can provide high-quality contact materials or precious metal materials by being observable and enabling a precise surface cutting process.

In addition, the die cutting portion 320 includes a cutting blade portion 322 that extends and protrudes from the cutting body 321 in a direction away from the bearing inclined protrusion 312, so that foreign matter cut from the surface of the electrical contact material is removed from the cutting blade. It can be spaced apart from the cutting hole 320C disposed in the center of the portion 322 and the cutting blade portion 322.

This has the technical effect of allowing cutting to proceed with precision by preventing cutting foreign matter from filling the cutting hole 320C and keeping it spaced apart from the cutting blade portion 322.

Accordingly, according to the embodiment, the surface shell of the electrical contact material or precious metal material is removed by the shaving die 300 for electrical contact according to the embodiment, and the electrical conductivity or glossiness is improved, thereby significantly improving the characteristics as an electrical contact or precious metal material. There is an improved technical effect.

The features, structures, effects, etc. described in the embodiments above are included in at least one embodiment and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, etc. illustrated in each embodiment can be combined or modified and implemented in other embodiments by a person with ordinary knowledge in the field to which the embodiments belong. Therefore, contents related to such combinations and modifications should be interpreted as being included in the scope of the embodiments.

Although the above description focuses on the examples, this is only an example and does not limit the examples, and those skilled in the art will understand that there are various options not exemplified above without departing from the essential characteristics of the examples. You will see that variations and applications of branches are possible. For example, each component specifically shown in the examples can be modified and implemented. And these variations and differences related to application should be interpreted as being included in the scope of the embodiments set forth in the appended claims.

Claims (5)

a first cylindrical rolling body;
a first rounding recess rolling portion disposed on the outer periphery of the first rolling body;
a second rolling body spaced apart from the first rounding recess rolling part and having a predetermined second rounding recess rolling part at positions corresponding to the upper and lower sides of the first rounding recess rolling part;
a fastening through hole penetrating the central axis of the first rolling body; and
It includes a fastening groove extending from the fastening through hole to the inside of the first rolling body,
The first rounding recess rolling portion includes a first rounding recess surface portion, 1-2, respectively disposed without a pattern and spaced apart from each other in a first region and a third region recessed along the outer circumference of the first rolling body. a rounding recess surface portion and a pattern in a second region recessed along the outer circumference of the first rolling body, and disposed between the first rounding recess surface portion and the first-second rounding recess surface portion. It includes a first rounding recess pattern portion,
The second rounding recess rolling portion includes a second rounding recess surface portion disposed without a pattern in a first area recessed along the circumference of the outer peripheral surface of the second rolling body, and a pattern on both sides of the second rounding recess surface portion. It includes a second rounding recess pattern portion and a third rounding recess pattern portion respectively disposed along the recessed perimeter of the outer peripheral surface of the second rolling body and spaced apart from each other with the second rounding recess surface portion interposed therebetween; ,
The first rounding recess pattern portion disposed in the second area recessed along the outer circumference of the first rolling body is the second rounding recess pattern portion disposed respectively along the recessed circumference of the outer circumference of the second rolling body. There is no overlap between the top and bottom of the recess pattern portion and the third rounding recess pattern portion,
The third rounding recess pattern portion is a rolling device for an electrical contact having a rounding recess that is not disposed on an axis perpendicular to the central axis of the first rolling body. According to paragraph 1,
The first rounding recess rolling part,
A rolling device for electrical contacts having a rounding recess, which is disposed on the outer periphery of the first rolling body along an axis perpendicular to the central axis of the first rolling body. According to paragraph 1,
The first rounding recess pattern portion,
A rolling device for electrical contacts having a rounding recess, which is disposed on an axis perpendicular to the central axis of the first rolling body. According to paragraph 1,
A rolling device for an electrical contact having a rounding recess, wherein the second rounding recess pattern portion is not disposed on an axis perpendicular to the central axis of the first rolling body. A rolling device for electrical contacts having a rounding recess according to any one of claims 1 to 4, which draws a billet cast from a predetermined molten metal; and
A shaving die for electrical contacts that cuts the surface of the wire from which the billet is drawn. Electrical contact manufacturing apparatus comprising a.

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