JP2021109222A - Resin application device onto inside surface of metal pipe - Google Patents

Abstract

To provide a resin application device onto an inside surface of a metal pipe capable of appropriately applying a resin for lubrication onto the inside surface of the metal pipe before performing cold drawing.SOLUTION: A resin application device 100 onto an inside surface includes a pole part 1 which is inserted to an inner part of a metal pipe P from the pipe end P2 side of the other side of the metal pipe and moves back and forth in a longitudinal direction of the metal pipe, a resin ejection nozzle 2 which is attached to a tip part of the pole part and ejects resin onto an inner surface of the metal pipe, a contact part 3 which is attached to the tip side of the resin ejection nozzle or is attached to the pole part on the rear end side of the resin ejection nozzle, has a size larger than an inside diameter of a mouth squeezed part P11 and smaller than an inside diameter of a straight part P13 and can be brought into contact with a taper part P12 and a contact detection part 4 which detects that the contact part is brought into contact with the taper part.SELECTED DRAWING: Figure 1

Description

The present invention relates to an inner surface resin coating device for a metal tube capable of appropriately applying a lubricating resin to the inner surface of the metal tube before cold drawing.

As a method for reducing the diameter of a metal pipe such as a steel pipe, a cold drawing process (cold drawing process) is known in which a plug or a mandrel is inserted into the metal tube and the metal tube is drawn through a die.
In this cold drawing process, in order to prevent seizure between the metal tube as the work material and the tool (plug, mandrel, die), the surface (outer surface) of the metal tube (outer surface) before the cold drawing process is performed. And the inner surface) is generally formed with a coating film for lubrication.

Various types of coatings are known for lubrication. Among them, a resin having excellent lubricity is used as a coating that facilitates cold drawing of metal pipes made of difficult-to-process materials such as high-alloy steels and Ni-based alloys. A coating has been proposed (see, for example, Patent Document 1).

Here, the inner diameter of one of the metal pipes before the cold drawing process (the tube end side to be inserted into the die first) is smaller than the inner diameter of the die used in the cold drawing process in order from the tube end. A mouth squeezing portion having an outer diameter, a tapered portion connected to the mouth squeezing portion and tapered toward the one end side of the pipe, and a straight portion connected to the tapered portion and having a constant diameter are provided. ing. The straight portion extends to the other end of the metal tube.
By passing the mouth drawing portion of this metal tube through a die first and performing cold drawing on the metal tube, the inner surface of the metal tube is a part of the tapered portion (one of the tapered portions on the side closer to the straight portion). The part) and the straight part come into contact with the plug, and the diameter is reduced.
Therefore, in order to effectively prevent seizure and prevent unnecessary use of resin, it is desired to form a resin film on a part of the tapered portion and the straight portion except for the mouth squeezed portion of the metal tube. There is.

Patent Document 1 describes immersing a metal tube in a tank containing a resin, or inserting a nozzle into the inner surface of the metal tube to spray-apply the resin (for example, paragraph 0069 of Patent Document 1). ).
However, the method of immersing in a tank has problems that the resin is wasted, it takes time to form a resin film, and the size of the apparatus becomes large.
Further, Patent Document 1 does not describe a specific content of the spray coating method, and there is no disclosure or suggestion that the resin is appropriately applied to a part of the tapered portion and the straight portion.

JP-A-2007-268580

The present invention has been made to solve the above-mentioned problems of the prior art, and the inner surface of the metal pipe capable of appropriately applying a lubricating resin to the inner surface of the metal pipe before the cold drawing process is performed. An object of the present invention is to provide a resin coating device.

In order to solve the above problems, the present invention is an inner surface resin coating device for applying a lubricating resin to the inner surface of a metal pipe before cold drawing, and the metal pipe is applied from one pipe end side. In this order, it has a mouth squeezing portion, a tapered portion connected to the mouth squeezing portion and tapered toward the pipe end side, and a straight portion connected to the tapered portion and having a constant diameter. The inner surface resin coating device is inserted into the inside of the metal pipe from the other pipe end side of the metal pipe, and is attached to a rod portion that moves forward and backward in the longitudinal direction of the metal pipe and the tip portion of the rod portion. A resin discharge nozzle that discharges resin to the inner surface of a metal tube and a resin discharge nozzle attached to the tip side of the resin discharge nozzle, or attached to the rod portion on the rear end side of the resin discharge nozzle, from the inner diameter of the mouth squeezing portion. Also includes a contact portion having a size smaller than the inner diameter of the straight portion and capable of contacting the tapered portion, and a contact detecting portion for detecting that the contact portion has come into contact with the tapered portion. Provided is an inner surface resin coating device for a metal tube.

According to the inner surface resin coating device according to the present invention, the resin is applied to the inner surface of the metal tube by discharging the resin from the resin discharge nozzle attached to the tip of the paddle portion inserted into the inside of the metal tube. ..
The inner surface resin coating device according to the present invention has a dimension larger than the inner diameter of the mouth squeezing portion of the metal tube on one tube end side and smaller than the inner diameter of the straight portion, and can contact the tapered portion. Since the contact portion and the contact detection portion for detecting that the contact portion has contacted the tapered portion are provided, the rod portion is inserted from the other pipe end side of the metal pipe, and the contact portion contacts the tapered portion. Can be detected. Therefore, the resin is discharged from the resin discharge nozzle after the contact portion comes into contact with the tapered portion, or the resin is discharged from the resin discharge nozzle immediately after the insertion of the paddle portion, and the resin is discharged when the contact portion contacts the tapered portion. By stopping the above, it is possible to appropriately apply the resin to a part of the tapered portion and the straight portion.

Preferably, the inner surface resin coating device according to the present invention has a traveling carriage that moves forward and backward in the longitudinal direction of the metal pipe, and is attached to the traveling carriage to move forward and backward integrally with the traveling carriage and of the rod portion. A cylinder device connected to a rear end portion that expands and contracts in the longitudinal direction of the metal pipe, and the contact detection unit includes a proximity sensor that is attached to the traveling carriage and moves back and forth integrally with the traveling carriage. It is provided with a jig attached to the rear end portion of the rod portion and for detecting whether or not the proximity sensor is close to the proximity sensor by the proximity sensor.

In the above preferred configuration, the jig faces, for example, the position of the proximity sensor (the position in the longitudinal direction of the metal tube) in the initial state (the state before the rod is inserted into the metal tube) (the position in the longitudinal direction of the metal tube). It is provided at a position (that is, a position equivalent to a proximity sensor in the longitudinal direction of the metal tube) (opposing in a direction orthogonal to the longitudinal direction of the metal tube). In this initial state, the proximity sensor detects that the jig is in close proximity to the proximity sensor.
Then, even when the contact portion first contacts the tapered portion of the metal pipe due to the traveling carriage moving (moving to one pipe end side of the metal pipe), the jig is brought close to the proximity sensor by the proximity sensor. Is detected.
Next, even if the traveling bogie tries to move further from the time when the contact portion first contacts the tapered portion, since the contact portion is in contact with the tapered portion, the contact portion, the resin discharge nozzle, the rod portion, and the jig The position does not change. On the other hand, when the traveling bogie tries to move further, the cylinder device contracts, so that the traveling bogie and the proximity sensor move. Since the position of the jig does not change and the proximity sensor advances, when the jig is out of the position facing the proximity sensor, the proximity sensor detects that the jig is not close to the proximity sensor. Will be.
Therefore, according to the above-mentioned preferable configuration, the contact portion comes into contact with the tapered portion by treating the time when the jig is detected not close to the proximity sensor as the time when the contact portion contacts the tapered portion. Can be reliably detected.

Preferably, the resin discharge nozzle is a bell cup nozzle that rotates around the central axis of the paddle portion, and the contact portion is attached to the tip end side of the resin discharge nozzle via a bearing.

According to the above preferred configuration, since the resin discharge nozzle is a bell cup nozzle, it is attached to the rod portion so as to be rotatable at high speed by an air motor around the central axis of the rod portion, and the resin discharge nozzle (bell cup nozzle) is rotated at high speed. By discharging the resin from a large number of small discharge ports provided in the above, it is possible to uniformly apply the resin to the inner surface of the metal tube in the circumferential direction.
According to the above preferable configuration, since the contact portion is attached to the tip end side of the resin discharge nozzle via a bearing, the contact portion does not rotate and stands still even if the resin discharge nozzle rotates. It becomes. Therefore, the contact portion and the tapered portion of the metal tube do not rub against each other due to the rotation of the contact portion, and the contact portion is less likely to be damaged.

Preferably, the paddle portion advances toward the one end side of the pipe until the contact detection unit detects that the contact portion has come into contact with the tapered portion, and then the rod portion moves toward the other pipe end. The resin is applied to the inner surface of the metal tube by discharging the resin from the resin discharge nozzle while retreating toward the end side.

According to the above preferred configuration, when the resin is applied to the inner surface of the metal pipe, the resin discharge nozzle and the paddle portion retreat from one pipe end side toward the other pipe end side. In other words, when the resin is applied to the inner surface of the metal tube, the paddle portion is located downstream of the resin discharge nozzle in the moving direction. Therefore, there is no possibility that the rod portion comes into contact with the inner surface portion of the metal tube after the resin is applied by the resin discharge nozzle, and there is no possibility that the resin applied to the inner surface is peeled off by the contact with the rod portion.

According to the inner surface resin coating device for a metal tube according to the present invention, it is possible to appropriately apply a lubricating resin to the inner surface of a metal tube before cold drawing.

It is a side view which shows typically the schematic structure of the inner surface resin coating apparatus which concerns on one Embodiment of this invention. A side view cross section schematically showing a schematic configuration of a tip portion of an inner surface resin coating device in a state where the paddle portion shown in FIG. 1 is inserted inside the metal tube and the contact portion shown in FIG. 1 is in contact with the tapered portion of the metal tube. It is a figure. It is a side view schematically explaining the outline of the operation of coating a resin on the inner surface of a metal tube by the inner surface resin coating device shown in FIG. 1. It is a side view sectional view schematically showing the schematic structure of the modification of the contact part shown in FIG.

Hereinafter, the inner surface resin coating device for a metal tube (hereinafter, appropriately simply referred to as “inner surface resin coating device”) according to an embodiment of the present invention will be described with reference to the accompanying drawings as appropriate.
FIG. 1 is a side view schematically showing a schematic configuration of an inner surface resin coating device according to the present embodiment (a view seen from a horizontal direction orthogonal to the longitudinal direction of a metal tube). FIG. 1 (a) is a diagram showing a state before inserting the paddle portion provided in the inner surface resin coating device into the inside of the metal tube, and FIG. 1 (b) is a diagram showing a state before the paddle portion included in the inner surface resin coating device is inserted. It is an enlarged view of. Note that in FIG. 1A, the piping is not shown. FIG. 2 shows a state in which the rod portion provided in the inner surface resin coating device according to the present embodiment is inserted inside the metal pipe, and the contact portion provided in the inner surface resin coating device according to the present embodiment is in contact with the tapered portion of the metal pipe. It is a side view cross-sectional view (cross-sectional view seen from the horizontal direction orthogonal to the longitudinal direction of a metal pipe) which shows schematic structure of the tip part of the inner surface resin coating apparatus. The broken line arrow shown in FIG. 2 means the resin discharge direction.
As shown in FIG. 1, the inner surface resin coating device 100 according to the present embodiment is a device for applying a lubricating resin to the inner surface of the metal tube P before the cold drawing process, and includes the rod portion 1 and the rod portion 1. It includes a resin discharge nozzle 2, a contact portion 3, and a contact detection unit 4. Further, the inner surface resin coating device 100 is
It includes a traveling carriage 5 and a cylinder device 6. Further, the inner surface resin coating device 100 includes pipes 7 and 8.

As shown in FIGS. 1A and 2, the metal pipe P to which the resin is coated on the inner surface by the inner surface resin coating device 100 according to the present embodiment is cold drawn in order from one pipe end P1 side. A mouth squeezing portion P11 having an outer diameter smaller than the inner diameter of the die (not shown) to be used, a tapered portion P12 connected to the mouth squeezing portion P11 and tapered toward the pipe end side P1, and a tapered portion P12. It has a straight portion P13 which is connected to and has a constant diameter. The straight portion P13 extends to the other pipe end P2 of the metal pipe.

The rod portion 1 is inserted into the inside of the metal pipe P from the other pipe end P2 side of the metal pipe P, and moves forward and backward in the longitudinal direction of the metal pipe P (the direction of the arrow X shown in FIG. 1A). Specifically, the rear end portion of the paddle portion 1 (the end portion on the side opposite to the end portion on the side where the metal tube P starts to be inserted. The right end portion in FIG. 1) is in the longitudinal direction of the metal tube P. It is connected to the traveling carriage 5 that advances and retreats, and when the traveling carriage 5 advances and retreats in the longitudinal direction of the metal pipe P, the paddle portion 1 also advances and retreats in the longitudinal direction of the metal pipe P.
The paddle portion 1 of the present embodiment includes a hollow portion 1a and a solid portion 1b, and the hollow portion 1a and the solid portion 1b are connected by a flange 1c. Pipes 7 and 8 are inserted into the hollow portion 1a. The paddle 1 is formed of, for example, a metal material such as carbon steel.

A guide portion 9 is attached to the paddle portion 1 of the present embodiment at an appropriate position in the longitudinal direction thereof. The guide portion 9 has a circular outer shape when viewed from the longitudinal direction of the metal tube P. The diameter (maximum diameter) of the guide portion 9 is larger than the diameter D1 of the contact portion 3 and the diameter (maximum diameter) of the resin discharge nozzle 2, and is smaller than the inner diameter of the straight portion P13 of the metal tube P. As a result, only the guide portion 9 comes into contact with the inner surface of the straight portion P13 of the metal pipe P, and the paddle portion 1 can smoothly advance and retreat without contacting the inner surface of the straight portion P13 of the metal pipe P. It is possible to avoid the possibility that the resin discharge nozzle 2 comes into contact with the inner surface of the straight portion P13 of the metal tube P and is damaged. The guide portion 9 is formed of, for example, MC nylon (registered trademark).

The resin discharge nozzle 2 is attached to the tip of the paddle 1 (the end on the side where it starts to be inserted into the metal tube P. The left end in FIG. 1), and the paddle 1 moves (of the metal tube P). By moving to one tube end P1 side), it is inserted into the inside of the metal tube P. The resin discharge nozzle 2 is connected to a resin supply source (not shown) via a pipe 7. The resin supplied from the resin supply source (for example, acrylic resin) is supplied to the resin discharge nozzle 2 through the pipe 7, and the resin discharge nozzle 2 discharges the supplied resin to the inner surface of the metal tube P.
In this embodiment, a bell cup nozzle is used as the resin discharge nozzle 2. The resin discharge nozzle (bell cup nozzle) 2 includes an air motor (not shown) and is connected to a compressed air source (not shown) via a pipe 8. The compressed air supplied from the compressed air source is supplied to the air motor of the resin discharge nozzle 2 through the pipe 8, and the resin discharge nozzle 2 is rotated at high speed around the central axis of the paddle 1 by the air motor. By discharging the resin from a large number of small discharge ports provided in the resin discharge nozzle 2 while rotating at high speed, it is possible to uniformly apply the resin to the inner surface of the metal tube P in the circumferential direction. As for the specific configuration of the bell cup nozzle used as the resin discharge nozzle 2, various known bell cup nozzles can be applied, and therefore detailed description thereof will be omitted here.

The contact portion 3 of the present embodiment is attached to the tip end side (one end portion P1 side of the metal tube P) of the resin discharge nozzle 2. Specifically, the contact portion 3 of the present embodiment is attached to the tip end side of the resin discharge nozzle 2 via a bearing (not shown). The contact portion 3 has a circular outer shape when viewed from the longitudinal direction of the metal tube P. As shown in FIG. 2, the diameter (maximum diameter) D1 of the contact portion 3 is larger than the inner diameter D2 of the mouth throttle portion P11 and smaller than the inner diameter D3 of the straight portion P13. As a result, the contact portion 3 can come into contact with the tapered portion P12. Further, the diameter D1 of the contact portion 3 is preferably larger than the diameter (maximum diameter) of the resin discharge nozzle 2. As a result, it is possible to prevent the resin discharge nozzle 2 from coming into contact with the tapered portion P12 before the contact portion 3 comes into contact with the tapered portion P12, and even if the entire paddle portion 1 is slightly bent due to its weight, It is possible to prevent the resin discharge nozzle 2 from coming into contact with the inner surface of the straight portion P13. The contact portion 3 is formed of, for example, MC nylon (registered trademark). The diameter D1 of the contact portion 3 is a portion where it is necessary to form a resin film in order to prevent seizure, specifically, when the metal tube P is cold drawn, the tapered portion P12 is formed. It may be determined according to the minimum diameter (corresponding to the maximum diameter of the plug) of the portion to be processed in contact with the plug (not shown).

The contact detection unit 4 detects that the contact unit 3 has come into contact with the tapered portion P12. The contact detection unit 4 of the present embodiment has a proximity sensor 41 attached to the traveling carriage 5 to move forward and backward integrally with the traveling carriage 5, and a proximity sensor 41 attached to the rear end of the paddle 1 by the proximity sensor 41. It is provided with a jig (also referred to as a dog) 42 for detecting whether or not it is close to the object.
As the proximity sensor 41, for example, an electromagnetic induction type proximity sensor or a capacitance type proximity sensor can be used.
As the jig 42, for example, an annular member formed of a metal material such as carbon steel can be used. The jig 42 of the present embodiment has the position of the proximity sensor 41 (the position in the longitudinal direction of the metal tube P) in the initial state shown in FIG. 1 (the state before the rod 1 is inserted into the metal tube P). ) (Is it facing the direction orthogonal to the longitudinal direction of the metal tube P (vertical direction in the example shown in FIG. 1)) (that is, the position equivalent to the proximity sensor 41 in the longitudinal direction of the metal tube P). Has been done. In this initial state, the proximity sensor 41 detects that the jig 42 is close to the proximity sensor 41.

The cylinder device 6 is attached to the traveling carriage 5 and moves back and forth integrally with the traveling carriage 5, and is connected to the rear end of the paddle 1 to expand and contract in the longitudinal direction of the metal pipe P. Specifically, the cylinder device 6 of the present embodiment is an air cylinder device including a cylinder 61 and a piston rod 62 that moves relative to the cylinder 61. The cylinder 61 is attached to a traveling carriage and a piston is provided. The rod 62 is connected to the rear end of the cylinder 1.

Hereinafter, the operation of applying the resin to the inner surface of the metal tube P by the inner surface resin coating device 100 having the above configuration will be described.
FIG. 3 is a side view (viewed from a horizontal direction orthogonal to the longitudinal direction of the metal tube) schematically explaining the outline of the operation of applying the resin to the inner surface of the metal tube P by the inner surface resin coating device 100. FIG. 3A is a diagram showing a state at the time when the contact portion 3 first contacts the tapered portion P12 of the metal tube P by moving the traveling carriage 5, and FIG. 3B is a diagram showing a state when FIG. FIG. 5 is a diagram showing a state in which the traveling carriage 5 is further advanced from the state shown in (a) and the contact detection unit 4 detects that the contact portion 3 has come into contact with the tapered portion P12.
When the resin is applied to the inner surface of the metal pipe P by the inner surface resin coating device 100, the traveling carriage 5 is moved from the initial state (the state before the rod portion 1 is inserted into the metal pipe P). , As shown in FIG. 3A, the rod portion 1 advances toward the one pipe end P1 side until the contact portion 3 comes into contact with the tapered portion P12 on the one pipe end P1 side of the metal pipe P. .. In the state shown in FIG. 3A, since the jig 42 is in a position facing the proximity sensor 41, the proximity sensor 41 detects that the jig 42 is close to the proximity sensor 41 as in the initial state. It remains.

Next, even if the traveling carriage 5 tries to move further from the state shown in FIG. 3A, since the contact portion 3 is in contact with the tapered portion P12, the contact portion 3, the resin discharge nozzle 2, the rod portion 1 and The position of the jig 42 does not change. On the other hand, when the traveling carriage 5 tries to move further, the cylinder device 6 contracts (the cylinder 61 moves toward the piston rod 62), so that the traveling carriage 5 and the proximity sensor 41 advance. Since the position of the jig 42 does not change and the proximity sensor 41 advances, as shown in FIG. 3B, when the jig 42 is displaced from the position facing the proximity sensor 41, the proximity sensor 41 Therefore, it is detected that the jig 42 is not close to the proximity sensor 41.
Therefore, the contact portion 3 is treated as the time when the contact portion 3 is in contact with the tapered portion P12 when it is detected that the jig 42 is not close to the proximity sensor 41 (the state shown in FIG. 3B). Can be reliably detected in contact with the tapered portion P12.

In the above example, the case where the proximity sensor 41 and the jig 42 face each other in the initial state has been described as an example, but the present invention is not limited to this. For example, in the initial state, the jig 42 is provided so that the jig 42 is displaced from the position facing the proximity sensor 41 to the one tube end P1 side, and the contact portion 3 first contacts the tapered portion P12. After that, it is also possible to adopt a mode in which the jig 42 is positioned so as to face the proximity sensor 41 by further advancing the traveling carriage 5. In this case, the time when the jig 42 is detected to be close to the proximity sensor 41 is treated as the time when the contact portion 3 comes into contact with the tapered portion P12, so that the contact portion 3 comes into contact with the tapered portion P12. It can be detected reliably.

Next, from the state shown in FIG. 3 (b), the traveling carriage 5 is retracted (moved to the right side in FIG. 3) while discharging the resin from the resin discharge nozzle 2, so that the rod portion 1 becomes the other pipe. Retreat toward the end P2 (see FIG. 1) side. When the resin discharge nozzle 2 reaches the pipe end P2 while discharging the resin, the resin can be applied to the entire inner surface of the metal pipe P (however, except for a part of the mouth squeezing portion P11 and the tapered portion P12). Is.
The moving speed of the resin discharge nozzle 2 and the resin discharge amount of the resin discharge nozzle 2 may be set so that a resin film having a desired film thickness can be uniformly formed on the inner surface of the metal tube P. The moving speed of the resin discharge nozzle 2 can be changed, for example, by using a traveling speed variable type as the traveling carriage 5 and adjusting the traveling speed of the traveling carriage 5. The resin discharge amount of the resin discharge nozzle 2 can be changed, for example, by adjusting the supply amount from the resin supply source.

According to the inner surface resin coating device 100 according to the present embodiment described above, it is possible to reliably detect that the contact portion 3 has come into contact with the tapered portion P12. Therefore, by discharging the resin from the resin discharge nozzle 2 after the contact portion 3 comes into contact with the tapered portion P12, a part of the tapered portion P12 and the straight portion P13 (from the contact point 31 of the contact portion 3 shown in FIG. 2 to the other). The resin can be appropriately applied to the inner surface of the metal tube P located on the end P2 side).

Further, according to the inner surface resin coating device 100 according to the present embodiment, since the contact portion 3 is attached to the tip end side of the resin discharge nozzle 2 via a bearing, contact even if the resin discharge nozzle 2 rotates. The unit 3 does not rotate and is in a stationary state. Therefore, the contact portion 3 and the tapered portion P12 of the metal tube P do not rub against each other due to the rotation of the contact portion 3, and the contact portion 3 is less likely to be damaged.

Further, according to the inner surface resin coating device 100 according to the present embodiment, the paddle portion 1 is directed toward one pipe end P1 side until the contact detection portion 4 detects that the contact portion 3 has come into contact with the tapered portion P12. After advancing, the resin is discharged from the resin discharge nozzle 2 while the paddle portion 1 retreats toward the other pipe end P2 side to apply the resin to the inner surface of the metal pipe P. That is, when the resin is applied to the inner surface of the metal pipe P, the resin discharge nozzle 2 and the paddle portion 1 retreat from one pipe end P1 side toward the other pipe end P2 side. In other words, when the resin is applied to the inner surface of the metal tube P, the paddle portion 1 is located downstream of the resin discharge nozzle 2 in the moving direction. Therefore, there is no possibility that the guide portion 9 or the paddle portion 1 comes into contact with the inner surface portion of the metal tube P after the resin is applied by the resin discharge nozzle 2, and the resin applied to the inner surface is the guide portion 9 or the paddle portion. There is no risk of peeling due to contact with 1.
However, the present invention is not limited to this, and adopts an embodiment in which the resin is discharged from the resin discharge nozzle 2 immediately after the insertion of the paddle portion 1 and the resin discharge is stopped when the contact portion 3 comes into contact with the tapered portion P12. It is also possible to do.

In the present embodiment, the case where the contact portion 3 is attached to the tip end side of the resin discharge nozzle 2 has been described as an example, but the present invention is not limited to this.
FIG. 4 is a side view cross-sectional view schematically showing a schematic configuration of a modified example of the contact portion (cross-sectional view seen from a horizontal direction orthogonal to the longitudinal direction of the metal tube P). FIG. 4A is a diagram showing a state in which the contact portion is in contact with the tapered portion P12 of the metal tube P, and FIG. 4B is a state in which resin is started to be discharged from the resin discharge nozzle 2. It is a figure. The broken line arrow shown in FIG. 4B means the discharge direction of the resin.
As shown in FIG. 4, the contact portion 3A according to the modified example is attached to the paddle portion 1 on the rear end side (the other end portion P2 side of the metal tube P) of the resin discharge nozzle 2. Specifically, in the example shown in FIG. 4, the guide portion 9 located on the most advanced side among the plurality of guide portions 9 functions as the contact portion 3A. As described above, the diameter (maximum diameter) of the guide portion 9 is larger than the diameter (maximum diameter) of the resin discharge nozzle 2 and smaller than the inner diameter D3 (see FIG. 2) of the straight portion P13 of the metal tube P. It has become. In addition to this, at least the diameter of the guide portion 9 on the most advanced side is made larger than the inner diameter D2 (see FIG. 2) of the mouth throttle portion P11, and the diameter (maximum diameter) of the resin discharge nozzle 2 is set to the inner diameter of the mouth throttle portion P11. By making it smaller than D2, the guide portion 9 on the most advanced side can function as the contact portion 3A. The contact portion 3A according to the modified example is particularly effective when the difference between the inner diameter D2 of the mouth throttle portion P11 and the inner diameter D3 of the straight portion is small. As described above, the diameter of the contact portion 3 attached to the tip of the resin discharge nozzle 2 is larger than the inner diameter D2 of the mouth throttle portion P11 and smaller than the diameter of the guide portion 9. However, when the difference between the inner diameter D2 of the mouth squeezing portion P11 and the inner diameter D3 of the straight portion is small, the difference between the inner diameter D2 of the mouth squeezing portion P11 and the diameter of the guide portion 9 becomes smaller, so that the diameter of the contact portion 3 This is because the selectable range becomes considerably small.

As shown in FIG. 4A, by advancing the traveling carriage 5 (see FIG. 1) (moving it to the left side of FIG. 4), the contact portion 3A contacts the tapered portion P12 of the metal tube P at the contact point 31A. The contact state can be detected by the contact detection unit 4 as in the case of the contact unit 3 described above.
Then, by retreating the traveling carriage 5 (see FIG. 1) (moving it to the right side of FIG. 4) from the state shown in FIG. 4 (a), the rod portion 1 becomes the other pipe end P2 (see FIG. 1). FIG. 4B shows the timing at which the resin is retracted toward the side and the resin discharged from the resin discharge nozzle 2 is applied to the position corresponding to the contact point 31A of the tapered portion P12 of the metal tube P. As described above, the resin may be discharged from the resin discharge nozzle 2. When the resin discharge nozzle 2 reaches the pipe end P2 while discharging the resin, it is possible to apply the resin to the entire inner surface of the metal pipe P (however, except for a part of the mouth squeezing portion P11 and the tapered portion P12). Is. The timing at which the resin is started to be discharged from the resin discharge nozzle 2 (the timing at which the discharged resin is applied to the position corresponding to the contact point 31A of the tapered portion P12 of the metal tube P) is the resin discharge nozzle 2. It can be determined in advance according to the distance between the and the contact portion 3A and the resin discharge direction.

Further, in the present embodiment, the configuration in which the contact detection unit 4 includes the proximity sensor 41 and the jig 42 has been described, but the present invention is not limited to this. For example, a pressure sensor attached to the tip end side of the contact portion 3 can be used as the contact detection portion. In this case, when the pressure detected by the pressure sensor becomes equal to or higher than a predetermined threshold value, it is possible to detect that the contact portion 3 has come into contact with the tapered portion P12.

Although detailed description is omitted, for example, the metal tube P before the cold drawing process is sequentially conveyed in the longitudinal direction and the horizontal direction orthogonal to the longitudinal direction, and is heated (not shown). The resin is applied to the outer surface by the outer surface resin coating device (not shown), the resin is applied to the inner surface by the inner surface resin coating device 100, and the air is blown to the inner surface by the blower (not shown). preferable. Then, after the resin applied to the outer surface and the inner surface of the metal tube P is dried to form a resin film on the outer surface and the inner surface of the metal tube P, the metal tube P is conveyed to a drawing machine for cold drawing. For example, it is possible to efficiently prevent seizure in the cold drawing process.

1 ... Rod part 2 ... Resin discharge nozzle 3 ... Contact part 4 ... Contact detection part 5 ... Traveling carriage 6 ... Cylinder device 100 ... Inner surface resin coating device P ... Metal tube P1 ... One tube end P2 ... The other tube end P11 ... Mouth squeezing part P12 ... Tapered part P13 ... Straight part

Claims (4)

An inner surface resin coating device that applies a lubricating resin to the inner surface of a metal tube before cold drawing.
The metal pipe is connected to a mouth squeezing portion, a tapered portion connected to the mouth squeezing portion and tapered toward the pipe end side, and a constant diameter connected to the tapered portion in order from one pipe end side. With a straight part,
The inner surface resin coating device is
A paddle portion that is inserted into the inside of the metal pipe from the other end side of the metal pipe and moves forward and backward in the longitudinal direction of the metal pipe.
A resin discharge nozzle attached to the tip of the paddle and discharging resin to the inner surface of the metal tube.
It is attached to the tip end side of the resin discharge nozzle, or is attached to the paddle portion on the rear end side of the resin discharge nozzle, and has a dimension larger than the inner diameter of the mouth throttle portion and smaller than the inner diameter of the straight portion. Then, with the contact portion that can contact the tapered portion,
A contact detecting portion for detecting that the contact portion has come into contact with the tapered portion is provided.
Inner surface resin coating device for metal pipes. A traveling carriage that moves forward and backward in the longitudinal direction of the metal pipe, and
A cylinder device that is attached to the traveling carriage and moves back and forth integrally with the traveling carriage and is connected to the rear end of the paddle and expands and contracts in the longitudinal direction of the metal pipe is provided.
The contact detection unit
A proximity sensor that is attached to the trolley and moves forward and backward integrally with the trolley,
A jig attached to the rear end of the paddle and detecting whether or not the proximity sensor is close to the proximity sensor is provided.
The inner surface resin coating device for a metal tube according to claim 1. The resin discharge nozzle is a bell cup nozzle that rotates around the central axis of the paddle portion.
The contact portion is attached to the tip end side of the resin discharge nozzle via a bearing.
The inner surface resin coating device for a metal tube according to claim 1 or 2. After the rod portion advances toward the one pipe end side until the contact detection portion detects that the contact portion has contacted the tapered portion, the rod portion moves to the other pipe end side. The resin is applied to the inner surface of the metal tube by discharging the resin from the resin discharge nozzle while retreating toward the metal tube.
The inner surface resin coating device for a metal tube according to any one of claims 1 to 3.

Images