KR102445676B1 - Apparatus and method of forming ultra-precision outer diameter of thin tube - Google Patents

Abstract

The present invention discloses an apparatus for forming an ultra-precision outer diameter of a thin tube. Ultra-precision outer diameter forming apparatus according to the present invention, a die holder having an outlet; A first die fixed to the die holder, which is formed along the circumferential direction on the inner wall of the first through hole and has a first molding part protruding therein, and a first die disposed under the first die and circumferentially on the inner wall of the second through hole a forming die formed along a direction and including a second die having a second forming portion protruding therein; and a guide punch installed on the upper portion of the forming die to ascend and descend, and the inner spaces of the first through hole, the second through hole and the outlet may be connected to each other and provided as a passage for the thin tube descending by the guide punch.
According to the present invention, it is possible to produce an ultra-precision thin tube with an outer diameter tolerance of 0.01 mm or less without using a centerless grinder. In addition, it is possible to achieve more than 4 times the production speed compared to the polishing process, and the accuracy and uniformity of quality are greatly improved, so productivity improvement and cost reduction can be maximized. In addition, since it can prevent dust or contamination due to the grinding process, it can provide a pleasant working environment and increase the safety and satisfaction of workers.

Description

Apparatus and method of forming ultra-precision outer diameter of thin tube

The present invention relates to an apparatus for forming an outer diameter of a thin tube, and more particularly, to an apparatus capable of producing an ultra-precision thin tube with an outer diameter tolerance of 0.01 mm or less using a multi-stage axial tube mold.

Recently, thin tubes with a wall thickness of 2 mm or less are widely used in various parts such as automobiles, electronic devices, and home appliances, and the demand for ultra-precision thin tubes with an outer diameter tolerance of 0.01 mm or less is increasing significantly. .

In general, thin tubes are produced through a drawing process, and even if a precise drawing process is performed, it is known to have an outer diameter tolerance of about 0.02 mm to 0.06 mm.

Therefore, in order to produce ultra-precision thin tubes with an outer diameter tolerance of 0.01 mm or less, an additional process for realizing ultra-precision dimensions for pipes produced in a pipe making machine must be performed.

The conventional method of implementing ultra-precision is a method of implementing ultra-precision dimensions by cutting the pipe to a predetermined length and chamfering, and then grinding the surface in a centerless grinder.

However, since the thin tube is very thin, there is a problem in that the tube is often damaged, such as being crushed or deformed due to the vibration and vibration of the guide during polishing in the centerless grinder.

In addition, during surface grinding with a grinder, contamination by scattering dust or cutting oil is severe and the working environment is poor, which can adversely affect the health of workers. There is a problem that you have to bear.

In addition, there is a problem that productivity is low and the production cost is relatively high because the production quantity per hour is small, and there is a problem in that the maintenance cost according to the dressing and replacement of the abrasive stone increases during long-term use.

Republic of Korea Patent Registration No. 10-1838602 (Notice on Mar. 14, 2018)

The present invention was devised in this background, and an object of the present invention is to provide a new molding apparatus and method capable of realizing ultra-precise dimensions of a thin tube without using a centerless grinder.

In order to achieve this object, an aspect of the present invention, a die holder having an outlet; A first die fixed to the die holder, which is formed along the circumferential direction on the inner wall of the first through hole and has a first molding part protruding therein, and a first die disposed under the first die and circumferentially on the inner wall of the second through hole a forming die formed along a direction and including a second die having a second forming portion protruding therein; and a guide punch installed on the upper part of the forming die to ascend and descend, and the inner spaces of the first through hole, the second through hole and the outlet are connected to each other and are provided as a passage for the thin tube descending by the guide punch. It provides an ultra-precision outer diameter forming apparatus.

In the ultra-precision outer diameter forming apparatus according to an aspect of the present invention, the inner diameter (D2) of the second forming part may be greater than the inner diameter (D1) of the first forming part.

In addition, in the ultra-precision outer diameter molding apparatus according to an aspect of the present invention, the molding die is formed in the circumferential direction on the inner wall of the third through hole as disposed below the second die and provided with a third molding part protruding to the inside It may include a third die.

In this case, the inner diameter D2 of the second molding part may be greater than the inner diameter D1 of the first molding part, and the inner diameter D3 of the third molding part may be the same as the inner diameter D2 of the second molding part.

In addition, the distance (L1) of the first molded part and the second molded part is 0.5 to 1 times the standard outer diameter of the thin tube, and the distance (L2) of the second molded part and the third molded part is the thickness of the thin tube. The outer diameter may be 1 to 2 times the standard dimension.

In addition, in the ultra-precision outer diameter forming apparatus according to an aspect of the present invention, the guide punch includes a taper portion inserted into the inside from the top of the thin tube and a locking jaw formed at the upper end of the tapered portion, and the outer diameter of the locking jaw is It may be larger than the inner diameter of the thin tube and smaller than the inner diameter D1 of the first molding part of the first die.

In addition, in the ultra-precision outer diameter forming apparatus according to an aspect of the present invention, an insert guide having a through hole communicating with the first through hole is installed on an upper portion of the first die, and a thin tube is provided on the upper end of the through hole of the insert guide. An extension may be formed for smooth insertion of

Another aspect of the present invention is a method for forming an outer diameter of a thin tube using the above-described ultra-precision outer diameter forming apparatus, the method comprising: lowering a first thin tube using the guide punch; raising the guide punch while the upper end of the first thin tube has passed through the first forming part; lowering the second thin tube using the guide punch; discharging to the outlet by pushing the upper end of the first thin tube while the second thin tube descends; It provides an ultra-precise outer diameter forming method of the thin tube comprising the step of raising the guide punch in a state in which the upper end of the second thin tube has passed through the first forming part.

According to the present invention, it is possible to produce an ultra-precision thin tube with an outer diameter tolerance of 0.01 mm or less without using a centerless grinder.

In addition, it is possible to achieve more than 4 times the production speed compared to the polishing process, and the accuracy and uniformity of quality are greatly improved, so productivity improvement and cost reduction can be maximized.

In addition, since it can prevent dust or contamination due to the grinding process, it can provide a pleasant working environment and increase the safety and satisfaction of workers.

1 is a cross-sectional view of a thin tube ultra-precision outer diameter forming apparatus according to an embodiment of the present invention;
2 is an exploded perspective view of the forming die;
3 is a cross-sectional view of a first of the forming die;
4 is an enlarged view of part A of FIG. 3
5 is a cross-sectional view of a second die of the forming die;
6 is an enlarged view of part B of FIG. 5
7 is a cross-sectional view of a third die of the forming die;
8 is an enlarged view of part C of FIG. 7
9 is a cross-sectional view of the forming die;
10 is a view showing a coupling relationship between the guide punch and the thin tube;
11 is a flowchart illustrating a method for forming a thin tube outer diameter according to an embodiment of the present invention;
12 to 16 are views sequentially showing the operation of the thin tube outer diameter forming apparatus according to an embodiment of the present invention.
17 is a cross-sectional view showing a modified example of a thin tube outer diameter forming apparatus according to an embodiment of the present invention;

Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.

For reference, in the drawings attached to the present specification, there are parts indicated with dimensions or ratios different from those of actuality, but this is for convenience of explanation and understanding, so it should be noted in advance that the scope of the present invention should not be construed as being limited thereto. In addition, in the present specification, when one element is connected or combined with another element, it is not only directly connected or combined with another element, but also indirectly connected or combined with another element interposed therebetween. also includes In addition, when one element is 'directly' connected or combined with another element, it means that it is connected or combined without another element in the middle. In addition, the inclusion of a certain component in a certain part means that other components may be further included, rather than excluding other components, unless otherwise specifically stated. Also, in the present specification, expressions such as before, after, left, right, up, and below are relative concepts that may vary depending on the viewing position, so the scope of the present invention is not necessarily limited to the corresponding expression.

Thin tube ultra-precision outer diameter forming apparatus 100 according to an embodiment of the present invention (hereinafter referred to as 'outer diameter forming apparatus' for convenience) is. As shown in the cross-sectional view of Figure 1, the die holder 110, the guide punch holder 120 disposed on the upper part of the die holder 110, and a plurality of guide posts for guiding the lifting motion of the guide punch holder 120. 130 , a guide punch 140 coupled to the guide punch holder 120 , and a forming die 150 disposed under the guide punch 140 .

The die holder 110 serves to fix and support the forming die 150 . An outlet 119 for discharging the thin tube passing through the forming die 150 may be formed in the center of the die holder 110 .

The guide punch holder 120 is fixed to the movable side of the hydraulic press by the shank 122, and moves up and down by the hydraulic press. The upper end of the guide bush 132 may be coupled to the guide punch holder 120 .

The lower end of the guide post 130 may be fixed to the die holder 110 , and the upper end may be inserted into the guide bush 132 . A bearing 134 for smooth lifting and lowering motion may be installed between the guide post 130 and the guide bush 132 . Contrary to what is shown in the drawing, the guide post 130 may be coupled to the upper guide punch holder 120 and the guide bush 132 may be coupled to the lower die holder 110 .

The guide punch 140 serves to push the thin tube into the molding die 150 , and is coupled to the bottom surface of the guide punch holder 120 and protrudes downward. It is preferable that the lower end of the guide punch 140 has a diameter smaller than the inner diameter of the thin tube and the upper end has a larger diameter than the inner diameter of the thin tube.

The forming die 150 includes a die body 151 having a through hole 159 penetrating vertically and having a lower end fixed to the die holder 110 , and a through hole 159 of the die body 151 from above. It includes an insert guide 160 , a first die 170 , a second die 180 , and a third die 190 sequentially installed from the bottom.

The insert guide 160 , the first die 170 , the second die 180 , and the third die 190 may each be made of a cemented carbide material.

In addition, the insert guide 160 , the first die 170 , the second die 180 , and the third die 190 are to be inserted and fixed inside the through hole 159 of the die body 151 through shrink fit. can

Referring to the exploded perspective view of FIG. 2 , the insert guide 160 , the first die 170 , the second die 180 , and the third die 190 have through-holes 169 , 179 , and 189 penetrated up and down, respectively. , 199), and each through-hole (169, 179, 189, 199) is provided as a passage through which the thin tube passes.

In addition, each of the through-holes 169, 179, 189, and 199 communicates with the lower outlet 119, and thus, the thin tube introduced through the insert guide 160 passes through the through-holes 179, 189, and 199 of the first to third dies. After passing sequentially, it is discharged and collected through the outlet 119 at the bottom.

In the drawings, the insert guide 160 , the first die 170 , the second die 180 , and the third die 190 are shown to have a circular planar shape, respectively, but the specific shape is not limited thereto. It may have a rectangular planar shape or may have other shapes.

The insert guide 160 serves to guide the thin tube so that it can be smoothly inserted into the first die 170 at the bottom. An enlarged extension 163 may be formed. In this case, the extension 163 may have a curved surface or a flat surface.

It is preferable that the inner diameter of the insert guide 160 is slightly larger than the standard outer diameter of the thin tube. Considering that the general outer diameter tolerance of the thin tube is about 0.02mm to 0.06mm, the inner diameter of the insert guide 160 is preferably about 0.06mm larger than the standard outer diameter of the thin tube. However, according to the experiment, it was found that most of the thin tubes are smoothly inserted even when the inner diameter of the insert guide 160 is about 0.04 to 0.05 mm larger than the standard outer diameter of the thin tube.

Meanwhile, since the insert guide 160 serves to guide the thin tube to be smoothly inserted into the lower first die 170, it may be omitted in some cases. The insert guide 160 and the first die 170 may be integrally manufactured without being separated, or an extension may be formed in the upper end of the through hole 179 of the first die 170 so that the thin tube can be smoothly inserted. because there is

The first die 170 , the second die 180 , and the third die 190 include a first forming part 173 for implementing an ultra-precision outer diameter inside the through-holes 179 , 189 , 199 , respectively. A second molding portion 183 and a third molding portion 193 are provided.

First, in the first die 170 , as shown in the cross-sectional view of FIG. 3 and the enlarged view of part A of FIG. 4 , a first molding part 173 is formed to protrude from the inner wall of the through hole 179 in the circumferential direction. Meanwhile, in FIGS. 4, 6 and 8 , the first molding part 173 , the second molding part 183 , and the third molding part 193 respectively protrude to a height that is visible to the naked eye, but this It is for the convenience of explanation and understanding, and in reality, the protruding height is only about 0.05 to 0.1 mm, so it is almost difficult to identify with the naked eye.

The first molding portion 173 of the first die 170 is preferably formed such that the inner diameter (D1) is smaller than the standard outer diameter of the thin tube by 0.025 to 0.03 mm. In the embodiment of the present invention, the inner diameter (D1) of the first forming part 173 was formed to be 0.03 mm smaller than the standard outer diameter of the thin tube.

Therefore, when the thin tube is forcibly passed through the first forming part 173 by pushing it, the outer diameter of the thin tube becomes smaller than the reference dimension and then increases again due to the springback phenomenon, but rather than the outer diameter before passing through the first forming part 173 . becomes smaller

According to the experiment, when the inner diameter (D1) of the first molded part 173 is 0.03 mm smaller than the standard outer diameter of the thin tube, the outer diameter of the thin tube while passing through the first molded part 173 is 0.025 to It was found to be reduced by about 0.03 mm.

The width W1 of the first molding part 173 may be appropriately selected according to the elasticity of the thin tube. For example, when the carbon content is 0.1% and the degree of elasticity is relatively low, the width W1 of the first molding part 173 is formed to be about 6 mm, and when the elasticity is high because the carbon content is high, the first molding part 173 is formed. ), it is preferable to form a width W1 of 6 mm or more.

In addition, an inlet-side inclined surface 174 whose height is lowered toward the top is formed at the upper end of the first forming part 173 , and an outlet-side inclined surface 175 whose height is lowered toward the bottom is formed at the lower end of the first forming part 173 . ) is formed. When the inclined surfaces are formed on both sides in this way, the thin tube inserted into the through hole 179 slides smoothly into the first forming part 173, and after passing through the first forming part 173, a sudden springback can be prevented. can

In the embodiment of the present invention, the width W11 of the inlet inclined surface 174 and the width W12 of the outlet inclined surface 175 are equally formed to be about 2 mm, but the specific numerical values are not limited thereto. In addition, the width W11 of the entrance-side inclined surface 174 and the width W12 of the exit-side inclined surface 175 may be formed differently.

In addition, in the inner wall of the through hole 179 of the first die 170 , the inner diameter D11 of the inlet inner wall 171 positioned above the first molding part 173 is the inner diameter of the insert guide 160 and the inner diameter of the insert guide 160 . The same or slightly larger ones are preferred. This is because only then, the lower end of the thin tube passing through the insert guide 160 can easily enter the through hole 179 of the first die 170 .

In the inner wall of the through hole 179 of the first die 170 , the inner diameter D12 of the outlet inner wall 173 positioned below the first forming part 173 is the inner diameter D11 of the inlet inner wall 171 . ) and preferably the same.

As shown in the cross-sectional view of FIG. 5 and the enlarged view of part B of FIG. 6 , the second die 180 has a second molding part 183 protruding from the inner wall of the through hole 189 in the circumferential direction.

The second molding portion 183 of the second die 180 is preferably formed such that the inner diameter (D2) is smaller than the outer diameter of the thin tube by about 0.01 to 0.023 mm. In the embodiment of the present invention, the inner diameter (D2) of the second molding part 183 was formed to be 0.01 mm smaller than the standard outer diameter of the thin tube.

Therefore, when the thin tube that has passed through the first die 170 is forcibly passed through the second molded part 183 , the outer diameter of the thin tube becomes smaller than the reference dimension and then increases again due to the springback phenomenon, but the second molded part It becomes smaller than the outer diameter before passing through (183).

According to the experiment, when the inner diameter (D2) of the second molded part 183 is 0.01 mm smaller than the reference dimension of the outer diameter of the thin tube, the outer diameter of the thin tube while passing through the second molded part 183 is 0.020 to It was found that the decrease was about 0.023 mm.

In particular, when the first die 170 and the second die 180 successively pass the thin tube having an outer diameter tolerance of about 0.02 mm to 0.06 mm, it was found that the outer diameter tolerance can be reduced to 0.01 mm or less.

The width W2 of the second molding part 183 may also be appropriately selected according to the elasticity of the thin tube. For example, when the carbon content is 0.1% and the elasticity is relatively low, the width W2 of the second molded part 183 is formed to be about 6 mm, and when the elasticity is high because the carbon content is high, the second molded part 183 ), it is preferable to form a width W2 of 6 mm or more.

In addition, the upper end of the second forming part 183 is formed with an inlet-side inclined surface 184, the height of which is lowered toward the top, and the lower end of the second forming part 183, the outlet-side inclined surface 185, which is lowered in height toward the bottom. ) is formed. When the inclined surfaces are formed on both sides in this way, the thin tube inserted into the through hole 189 of the second die slides smoothly and enters the second forming part 183 , and after passing through the second forming part 183 , a sudden spring back can be prevented.

In the embodiment of the present invention, the width W21 of the entrance-side inclined surface 184 of the second die 180 is formed to be about 1.07 mm, and the width W22 of the exit-side inclined surface 185 is formed to be about 1.29 mm. is not limited thereto.

In addition, in the inner wall of the through hole 189 of the second die 180 , the inner diameter D21 of the inlet inner wall 181 positioned above the second molding part 183 is the outlet of the first die 170 . It is preferable that the inner diameter (D12) of the side inner wall 172 is equal to or slightly larger than that. This is because only then, the lower end of the thin tube passing through the first die 170 can easily enter the through hole 189 of the second die 180 .

In the inner wall of the through hole 189 of the second die 180 , the inner diameter D22 of the outlet inner wall 183 positioned below the second forming part 183 is the inner diameter D21 of the inlet inner wall 181 . ) greater than or equal to

As shown in the cross-sectional view of FIG. 7 and the enlarged view of part C of FIG. 8 , the third die 190 has a third molded part 193 protruding from the inner wall of the through hole 199 in the circumferential direction.

In this case, the inner diameter D3 of the third forming part 193 of the third die 190 is preferably the same as the inner diameter D2 of the second forming part 183 of the second die 180 . That is, it is preferable to form the inner diameter (D3) of the third molding part 193 smaller than the standard outer diameter of the thin tube by about 0.01 to 0.013 mm.

In the embodiment of the present invention, the inner diameter (D3) of the third molding part 193 was formed to be 0.01 mm smaller than the reference dimension of the outer diameter of the thin tube, similarly to the inner diameter (D2) of the second molding part 183 .

Therefore, although the third die 190 performs outer diameter molding on the thin tube that has passed through the second die 180, the main purpose is to form a third molded part ( 193) to prevent the outer diameter dimension of the thin tube passing through the second die 180 from changing due to the elastic restoring force of the material.

The width W3 of the third molding part 193 may also be appropriately selected according to the elasticity of the thin tube. For example, when the carbon content is 0.1% and the elasticity is relatively low, the width W3 of the third molded part 193 is formed to be about 6 mm, and when the elasticity is high because the carbon content is high, the third molded part 193 ), it is preferable to form a width W3 of 6 mm or more.

In addition, an entrance-side inclined surface 194 having a lower height as it goes upward is formed at the upper end of the third forming part 193 , and an outlet-side inclined surface 195 having a lower height toward the bottom at the lower end of the third forming part 193 is formed. ) is formed. When the inclined surfaces are formed on both sides in this way, the thin tube inserted into the through hole 199 of the third die smoothly slides into the third forming part 193 , and after passing through the third forming part 193 , an abrupt spring back can be prevented.

In the embodiment of the present invention, the width W31 of the entrance-side inclined surface 194 of the third die 190 is about 1.07 mm, and the width W32 of the exit-side inclined surface 195 is about 1.31 mm. is not limited thereto.

In addition, in the inner wall of the through hole 199 of the third die 190 , the inner diameter D31 of the inlet inner wall 191 positioned above the third molding part 193 is the outlet of the second die 120 . It is preferable that the inner diameter (D22) of the side inner wall 182 is equal to or slightly larger than that. This is because the lower end of the thin tube passing through the second die 180 can easily enter the through hole 199 of the third die 190 only by doing so.

In the inner wall of the through hole 199 of the third die 190 , the inner diameter D32 of the outlet inner wall 193 positioned below the third forming part 193 is the inner diameter D31 of the inlet inner wall 191 . ) is preferably greater than or equal to

Meanwhile, when the first to third dies 170 , 180 , and 190 are stacked, the gap L1 between the first molding part 173 and the second molding part 183 and the second molding part 183 and the third molding part 193 ) may be selected in consideration of the outer diameter dimension of the thin tube.

For example, it is preferable that the interval L1 between the first molded part 173 and the second molded part 183 is 0.5 to 1 times the standard outer diameter of the thin tube.

If the interval L1 between the first forming part 173 and the second forming part 183 is less than 0.5 times the outer diameter reference dimension, the thin tube passing through the first forming part 173 is sufficiently spring-backed before the second Since it enters the forming part 183, the elastic force is accumulated and the springback occurs larger after passing through the second forming part 183, so there is a problem that the outer diameter molding is not performed properly, and the interval L1 is 1 of the outer diameter standard dimension. If it is larger than the double, there is a problem in that the size of the forming die 150 is excessively large compared to the size of the thin tube.

In addition, it is preferable that the interval L2 between the second molded part 183 and the third molded part 193 is 1 to 2 times compared to the standard outer diameter of the thin tube.

If the distance L2 between the second forming part 183 and the third forming part 193 is less than one time of the outer diameter reference dimension, the thin tube passing through the second forming part 183 is sufficiently springback before the third Since it enters the forming part 193, the elastic force is accumulated and the springback occurs larger after passing through the third forming part 193, so there is a problem that outer diameter shaping is not performed properly, and the gap L2 is 2 of the outer diameter standard dimension. If it is larger than the double, there is a problem in that the size of the forming die 150 is excessively large compared to the size of the thin tube.

In addition, the specific dimensions of the gap (L1) and the gap (L2) are preferably appropriately selected within the above range according to the material properties (carbon content, elasticity) of the thin tube.

Referring to (a) of FIG. 10 , the guide punch 140 has a tapered portion 142 whose diameter decreases toward the lower end, and a locking protrusion 144 is formed on the upper end of the tapered portion 142 .

The lower diameter of the tapered portion 142 is smaller than the inner diameter of the thin tube 10 , and the upper engaging jaw 144 is larger than the inner diameter of the thin tube 10 . Therefore, when the guide punch 140 descends, as shown in FIG. After being caught on the top, the locking jaw 144 serves to forcibly push the thin tube 10 downward.

Hereinafter, an ultra-precise outer diameter forming method of a thin tube according to an embodiment of the present invention will be described with reference to the flowchart of FIG. 11 and the process flowchart of FIGS. 12 to 16 .

First, a thin tube 10 to be molded is prepared by cutting and chamfering a pipe with a wall thickness of 2.0 mm or less. In an embodiment of the present invention, it is preferable to perform the molding process for the thin tube 10 having a length of less than 6 times the outer diameter.

Then, as shown in FIG. 12 , the thin tube 10 is inserted into the through hole 169 of the insert guide 160 provided at the upper end of the forming die 150 in a state in which the guide punch 140 is raised. At this time, it is preferable to sufficiently push the thin tube 10 until the lower end of the thin tube 10 enters the interior of the first die 170 . (ST11)

Then, when the guide punch 140 is lowered by manipulating a switch or the like, as described with reference to FIG. The thin tube 10 is forcibly lowered by the jaws 144 .

13 shows a state in which the guide punch 140 is lowered to the maximum, the upper end of the thin tube 10 is a state passing through the first forming part 173 of the first die 170, and the lower end is the third die It is preferable to be in the state of passing up to the third shaping|molding part 193 of (190).

On the other hand, in order for the upper end of the thin tube 10 to be pushed by the guide punch 140 to pass through the first forming portion 173 of the first die 170 , the outer diameter of the engaging protrusion 144 of the guide punch 140 is the first Of course, it should be smaller than the inner diameter (D1) of the molding portion (173). (ST12, ST13)

In this way, since the thin tube 10 cannot be further lowered in the state in which the guide punch 140 is lowered to the maximum, in the embodiment of the present invention, after raising the guide punch 140 as shown in FIGS. Prepare the thin tube (10a) of 2 and insert it into the through hole (169) of the insert guide (160). (ST14, ST15)

In this state, if the guide punch 140 is lowered again by manipulating a switch or the like, as shown in FIG. 16 , the lower tapered portion 142 of the guide punch 140 moves into the inside of the second thin tube 10a. In the entered state, the second thin tube 10a is lowered.

When the second thin tube 10a is lowered in this way, the lower end of the second thin tube 10a is the first to third dies 170, 180, 190 of the thin tube 10 remaining inside the Push the upper end to discharge through the outlet 119 at the bottom.

In this process, the thin tube 10 that was loaded first passes through each of the forming portions 173.183.193 of the first to third dies 170, 180, and 190 sequentially to secure an ultra-precise outer diameter dimension.

In addition, the second thin tube 10a remains inside the first to third dies 170 , 180 , 190 , and then the first to third dies 170 , 180 by the third thin tube supplied thereto. , 190) while sequentially passing through each of the forming parts 173.183.193, it is possible to secure an ultra-precise outer diameter dimension. (ST16, ST17)

Although preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and may be implemented with various modifications or modifications in a specific application process.

As an example, in the above embodiment, the forming die 150 has been described as including the first to third dies 170 , 180 , 190 , but depending on the elasticity of the thin tube 10 , the second die 180 . ) and the third die 190 may be omitted to have a two-stage structure.

For example, as in the outer diameter forming apparatus 100a illustrated in FIG. 17 , only the insert guide 160 , the first die 170 , and the third die 190 sequentially from the top inside the die body 151 . can also be placed. Alternatively, only the insert guide 160 , the first die 170 , and the second die 180 may be disposed.

As described above, since the inner diameter D2 of the second forming part 183 of the second die 180 and the inner diameter D3 of the third forming part 193 of the third die 190 are substantially the same, the material This is because, when the elasticity is relatively low, even if any one of the second die 180 and the third die 190 is omitted, an ultra-precise outer diameter can be implemented.

As another example, as described above, the insert guide 160 disposed on the upper end of the forming die 150 may be omitted or may be formed integrally with the first die 170 .

As another example, in the above-described embodiment, when the thin tube 10 is loaded into the forming die 150 of the outer diameter forming apparatus 100, it has been described as manually loading, but using an automatic loading device, the thin tube 10 ) can be loaded, of course.

As such, the present invention can be implemented with various modifications or variations, and if the modified or modified embodiment includes the technical idea of the present invention disclosed in the claims described below, it will be natural to fall within the scope of the present invention.

10: thin tube 100: outer diameter forming device 110: die holder
119: outlet 120: guide punch holder 122: shank
130: guide post 132: guide bush 134: bearing
140: guide punch 142: tapered portion 144: engaging jaw
150: forming die 151: die body 159: through hole
160: insert guide 163: extension 169: through hole
170: first die 171: entrance-side inner wall 172: exit-side inner wall
173: first forming part 174: entrance-side inclined surface 175: exit-side inclined surface
179: through hole 180: second die 181: entrance side inner wall
182: exit side inner wall 183: second molded part 184: entrance side inclined surface
185: exit side inclined surface 189: through hole 190: third die
191: entrance-side inner wall 192: exit-side inner wall 193: third molded part
194: entrance side slope 195: exit side slope 199: through hole
D1, D2, D3: the inner diameter of the first, second, and third molding parts
W1, W2, W3: Widths of the first, second, and third molding parts
L1: gap between the first molding part and the second molding part
L2: the gap between the second molded part and the third molded part

Claims (8)

a die holder having an outlet;
A first die fixed to the die holder, which is formed along the circumferential direction on the inner wall of the first through hole and has a first molding part protruding therein, and a first die disposed under the first die and circumferentially on the inner wall of the second through hole a forming die formed along a direction and including a second die having a second forming portion protruding therein;
A guide punch installed on the upper part of the forming die and ascending and descending
including,
The inner diameter (D1) of the first molded part and the inner diameter (D2) of the second molded part are each smaller than the outer diameter reference dimension of the thin tube,
The inner diameter (D2) of the second molded part is greater than the inner diameter (D1) of the first molded part,
The first through-hole, the second through-hole, and the inner space of the outlet are connected to each other and are provided as a passage for a thin tube descending by a guide punch. The method of claim 1,
The distance (L1) of the first molding part and the second molding part is an ultra-precision outer diameter molding apparatus, characterized in that 0.5 to 1 times the standard outer diameter of the thin tube. The method of claim 1,
The forming die includes a third die disposed under the second die and formed along the inner wall of the third through hole in the circumferential direction and having a third forming portion protruding therein,
The inner diameter (D3) of the third shaping part is the same as the inner diameter (D2) of the second shaping part. delete 4. The method of claim 3,
The distance (L2) of the second molding part and the third molding part is an ultra-precision outer diameter molding apparatus, characterized in that one to two times the standard outer diameter of the thin tube. The method of claim 1,
The guide punch includes a tapered portion inserted into the inside from the upper end of the thin tube and a locking protrusion formed at the upper end of the tapered portion,
The outer diameter of the locking protrusion is larger than the inner diameter of the thin tube and is smaller than the inner diameter (D1) of the first forming part of the first die. The method of claim 1,
An insert guide having a through-hole communicating with the first through-hole is installed on the upper portion of the first die, and an extension for smooth insertion of the thin tube is formed at the upper end of the through-hole of the insert guide. molding device. a die holder having an outlet; A first die fixed to the die holder, which is formed along the circumferential direction on the inner wall of the first through hole and has a first molding part protruding therein, and a first die disposed under the first die and circumferentially on the inner wall of the second through hole a forming die formed along a direction and including a second die having a second forming portion protruding therein; Ultra-precision outer diameter molding that is installed on the upper portion of the forming die and includes a guide punch that ascends and descends, and the inner spaces of the first through hole, the second through hole and the outlet are connected to each other and provided as a passage for the thin tube descending by the guide punch. In the method of forming the outer diameter of a thin tube using an apparatus,
lowering the first thin tube using the guide punch;
raising the guide punch while the upper end of the first thin tube has passed through the first forming part;
lowering the second thin tube using the guide punch;
discharging to the outlet by pushing the upper end of the first thin tube while the second thin tube descends;
Raising the guide punch in a state where the upper end of the second thin tube has passed through the first forming part
Ultra-precision outer diameter forming method of a thin tube comprising

Images