JP7343780B2 - Metal tube inner surface resin coating equipment - Google Patents

Description

The present invention relates to an apparatus for applying resin on the inner surface of a metal tube, which is 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 metal pipes such as steel pipes, cold drawing is known, in which a plug or a mandrel is inserted into the metal pipe, and the metal pipe is drawn through a die.
In this cold drawing process, in order to prevent seizure between the metal tube as the workpiece and tools (plugs, mandrels, dies), the surface (outer surface) of the metal tube is It is common to form a lubricating film on the surface (and inner surface).

Various lubricating coatings are known, among which resins with excellent lubricity are used as coatings that facilitate cold drawing of metal tubes made of difficult-to-process materials such as high-alloy steel and Ni-based alloys. A coating has been proposed (for example, see Patent Document 1).

Here, one tube end side of the metal tube before cold drawing processing (the tube end side inserted into the die first) has a diameter smaller than the inner diameter of the die used in cold drawing processing, starting from the tube end. A constricted portion having an outer diameter, a tapered portion connected to the constricted portion and tapered in diameter toward the one end of the tube, and a straight portion connected to the tapered portion and having a constant diameter. ing. The straight portion extends to the other end of the metal tube.
By first passing the narrowed part of the metal tube through a die and subjecting the metal tube to cold drawing, a part of the tapered part (the part of the tapered part near the straight part) is drawn on the inner surface of the metal tube. part) and the straight part come into contact with the plug, and the diameter is reduced.
Therefore, in order to effectively prevent seizure and to prevent wasteful use of resin, it is desirable to form a resin coating on a part of the tapered part and the straight part of the metal tube, excluding the constricted part. There is.

Patent Document 1 describes that a metal tube is immersed in a tank filled with resin, and that a nozzle is inserted into the inner surface of the metal tube to spray coat the resin (for example, see paragraph 0069 of Patent Document 1). ).
However, the method of immersing the resin in a tank wastes resin, takes time to form a resin film, and increases the size of the device.
Further, regarding the method of spray coating, Patent Document 1 does not describe specific contents, and does not disclose or suggest how to appropriately apply the resin to a portion of the tapered portion and the straight portion.

JP2007-268580A

The present invention has been made to solve the problems of the prior art described above, and provides an inner surface of a metal tube that allows a lubricating resin to be appropriately applied to the inner surface of the metal tube before cold drawing. An object of the present invention is to provide a resin coating device.

In order to solve the above problems, the present invention provides an inner surface resin coating device that coats a lubricating resin on the inner surface of a metal tube before cold drawing, wherein the metal tube is coated with lubricating resin from one tube end side. The pipe has, in order, a mouth constriction part, a taper part connected to the mouth constriction part and tapered in diameter toward the tube end side, and a straight part connected to the taper part and having a constant diameter, and The inner surface resin coating device is inserted into the metal tube from the other end of the metal tube, and is attached to a rod portion that moves forward and backward in the longitudinal direction of the metal tube, and a tip portion of the rod portion, and is attached to the tip portion of the rod portion. a resin discharge nozzle that discharges resin onto the inner surface of a metal tube; a contact portion that is larger than the inner diameter of the straight portion and is capable of contacting the tapered portion; a contact detection portion that detects that the contact portion has contacted the tapered portion; and the metal tube. a traveling trolley that moves forward and backward in the longitudinal direction; and a traveling trolley that is attached to the traveling trolley and moves forward and backward integrally with the traveling trolley, and that is connected to the rear end of the rod and expands and contracts in the longitudinal direction of the metal tube. a cylinder device, and the contact detection unit includes a proximity sensor that is attached to the traveling truck and moves forward and backward integrally with the traveling truck, and a proximity sensor that is attached to the rear end of the rod portion and is activated by the proximity sensor. Provided is an apparatus for applying resin on the inner surface of a metal tube , which includes a jig that detects whether or not the object is close to a proximity sensor .

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 rod inserted into the interior of the metal tube. .
The inner surface resin coating device according to the present invention has dimensions larger than the inner diameter of the constricted part that the metal pipe has on one end of the pipe and smaller than the inner diameter of the straight part, so that the metal pipe can come into contact with the tapered part. Since it includes a contact portion and a contact detection portion that detects that the contact portion has contacted the tapered portion, it is possible to detect when the rod portion is inserted from the other end of the metal tube and the contact portion has contacted the tapered portion. can be detected. Therefore, the resin is discharged from the resin discharge nozzle after the contact part contacts the tapered part, or the resin is discharged from the resin discharge nozzle immediately after the rod is inserted, and the resin is discharged when the contact part contacts the tapered part. By stopping the process, it is possible to appropriately apply the resin to a part of the tapered part and the straight part.

Further, in the present invention , the jig is, for example, opposed to the position of the proximity sensor (position in the longitudinal direction of the metal tube) in the initial state (state before the rod is inserted into the metal tube). The sensor is provided at a position opposite to the direction perpendicular to the longitudinal direction of the metal tube (that is, at a position equivalent to the proximity sensor in the longitudinal direction of the metal tube). In this initial state, the proximity sensor detects that the jig is close to the proximity sensor.
Even when the contact part first contacts the tapered part of the metal pipe as the traveling cart advances (moves to one end of the metal pipe), the proximity sensor detects that the jig approaches the proximity sensor. It will be detected if
Next, even if the traveling trolley tries to move further from the point where the contact part first contacts the taper part, since the contact part is in contact with the taper part, the contact part, resin discharge nozzle, rod part, and jig will be damaged. The position does not change. On the other hand, when the traveling carriage attempts to move further, the cylinder device contracts, causing the traveling carriage and the proximity sensor to move. Since the position of the jig does not change and the proximity sensor advances, if the jig moves away from the position facing the proximity sensor, the proximity sensor will detect that the jig is not close to the proximity sensor. That will happen.
Therefore, according to the present invention , by treating the time when it is detected that the jig is not close to the proximity sensor as the time when the contact portion has contacted the tapered portion, it is possible to ensure that the contact portion has contacted the tapered portion. can be detected.

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

According to the above preferred configuration, since the resin discharging nozzle is a bell cup nozzle, the resin discharging nozzle (bell cup nozzle) is attached to the neck part so as to be able to rotate at high speed around the central axis of the neck part using an air motor, and the resin discharging nozzle (bell cup nozzle) By discharging the resin from a large number of small discharge ports provided in the metal tube, it is possible to uniformly apply the resin to the inner surface of the metal tube in the circumferential direction.
According to the above preferred configuration, the contact part is attached to the tip side of the resin discharge nozzle via a bearing, so even if the resin discharge nozzle rotates, the contact part remains stationary without rotating. becomes. Therefore, the contact portion and the tapered portion of the metal tube do not rub against each other due to rotation of the contact portion, and the contact portion is less likely to be damaged.

Preferably, after the rod portion moves toward the one tube end until the contact detection portion detects that the contact portion contacts the tapered portion, the rod portion moves toward the other tube end. The resin is applied to the inner surface of the metal tube by discharging the resin from the resin discharging nozzle while retracting toward the end.

According to the above preferred configuration, when resin is applied to the inner surface of the metal tube, the resin discharge nozzle and the rod retract from one tube end side toward the other tube end side. In other words, when resin is applied to the inner surface of the metal tube, the rod portion is located downstream in the moving direction than the resin discharge nozzle. Therefore, there is no risk that the rod portion will come into contact with the inner surface of the metal tube after the resin has been applied by the resin discharge nozzle, and there is no risk that the resin applied to the inner surface will peel off due to contact with the rod portion.

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

1 is a side view schematically showing a schematic configuration of an inner surface resin coating device according to an embodiment of the present invention. A side cross-sectional view schematically showing the schematic configuration of the tip of the internal resin coating device in a state where the rod shown in FIG. 1 is inserted into the metal tube and the contact part shown in FIG. 1 is in contact with the tapered part of the metal tube. It is a diagram. FIG. 2 is a side view schematically illustrating an outline of the operation of applying resin to the inner surface of a metal tube using the inner surface resin coating apparatus shown in FIG. 1 . FIG. 2 is a side cross-sectional view schematically showing a schematic configuration of a modified example of the contact portion shown in FIG. 1. FIG.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an apparatus for applying resin on the inner surface of a metal tube (hereinafter referred to simply as "resin coating apparatus for inner surface") 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 (viewed from a horizontal direction perpendicular to the longitudinal direction of the metal tube) schematically showing the schematic configuration of the inner surface resin coating apparatus according to the present embodiment. FIG. 1(a) is a diagram showing the state before the rod part of the inner surface resin coating device is inserted into the metal tube, and FIG. 1(b) is a diagram showing the inner surface resin coating device shown in FIG. 1(a). It is an enlarged view of. Note that in FIG. 1(a), illustration of piping is omitted. FIG. 2 shows a state in which the rod portion of the inner surface resin coating device according to the present embodiment is inserted into the inside of the metal tube, and the contact portion of the inner surface resin coating device according to the present embodiment is in contact with the tapered portion of the metal tube. FIG. 2 is a side cross-sectional view (a cross-sectional view seen from a horizontal direction orthogonal to the longitudinal direction of the metal tube) schematically showing the schematic configuration of the tip portion of the inner surface resin coating device. The broken line arrow shown in FIG. 2 means the resin discharge direction.
As shown in FIG. 1, an inner surface resin coating device 100 according to the present embodiment is a device that coats a lubricating resin on the inner surface of a metal tube P before cold drawing, and includes a rod portion 1, It includes a resin discharge nozzle 2, a contact section 3, and a contact detection section 4. Further, the inner surface resin coating device 100 includes:
It includes a traveling truck 5 and a cylinder device 6. Further, the inner surface resin coating device 100 includes pipes 7 and 8.

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

The rod portion 1 is inserted into the metal tube P from the other tube end P2 side of the metal tube P, and moves forward and backward in the longitudinal direction of the metal tube P (in the direction of arrow X shown in FIG. 1(a)). Specifically, the rear end of the rod portion 1 (the end opposite to the end where it begins to be inserted into the metal tube P; the end on the right side in FIG. 1) extends in the longitudinal direction of the metal tube P. It is connected to a traveling trolley 5 that moves forward and backward, and as the traveling trolley 5 moves forward and backward in the longitudinal direction of the metal tube P, the rod portion 1 also moves forward and backward in the longitudinal direction of the metal tube P.
The neck portion 1 of this 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 rod portion 1 is made of, for example, a metal material such as carbon steel.

Guide portions 9 are attached to the rod portion 1 of this embodiment at appropriate locations in its longitudinal direction. 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 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 tube P, and the rod portion 1 can move forward and backward smoothly without contacting the inner surface of the straight portion P13 of the metal tube P. It is possible to avoid the possibility that the resin discharge nozzle 2 will come into contact with the inner surface of the straight portion P13 of the metal tube P and be damaged. The guide portion 9 is made of, for example, MC nylon (registered trademark).

The resin discharge nozzle 2 is attached to the tip of the rod 1 (the end that begins to be inserted into the metal tube P; the left end in FIG. 1), and the rod 1 moves forward (the end of the metal tube (moves to one tube end P1 side), and 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. Resin (for example, acrylic resin) supplied from the resin supply source is supplied to the resin discharge nozzle 2 through the pipe 7, and the resin discharge nozzle 2 discharges the supplied resin onto the inner surface of the metal pipe 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. Compressed air supplied from the compressed air source is supplied to the air motor of the resin discharge nozzle 2 through the piping 8, and the resin discharge nozzle 2 is rotated at high speed around the central axis of the rod portion 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. Regarding the specific configuration of the bell cup nozzle used as the resin discharge nozzle 2, since various known bell cup nozzles can be applied, a detailed explanation will be omitted here.

The contact portion 3 of this embodiment is attached to the tip side of the resin discharge nozzle 2 (on the side of one end P1 of the metal tube P). Specifically, the contact portion 3 of this embodiment is attached to the tip 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 part 3 is larger than the inner diameter D2 of the aperture part P11 and smaller than the inner diameter D3 of the straight part P13. Thereby, the contact portion 3 can contact 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. This prevents the resin discharge nozzle 2 from coming into contact with the tapered part P12 before the contact part 3 comes into contact with the tapered part P12, and even if the entire rod part 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 made of, for example, MC nylon (registered trademark). Note that the diameter D1 of the contact portion 3 is the portion where it is necessary to form a resin film to prevent seizure, specifically, the diameter D1 of the tapered portion P12 when cold drawing is applied to the metal tube P. It may be determined according to the minimum diameter (corresponding to the maximum diameter of the plug) of the portion that will be processed in contact with the plug (not shown).

The contact detection section 4 detects that the contact section 3 has contacted the tapered section P12. The contact detection unit 4 of the present embodiment includes a proximity sensor 41 that is attached to the traveling truck 5 and moves forward and backward integrally with the traveling truck 5, and a proximity sensor 41 that is attached to the rear end of the pole portion 1. A jig (also referred to as a dog) 42 for detecting whether or not the object is close to the object is provided.
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 made of a metal material such as carbon steel can be used. The jig 42 of this embodiment has a position of the proximity sensor 41 (a position in the longitudinal direction of the metal tube P) in the initial state shown in FIG. ) (in other words, at the same position as the proximity sensor 41 in the longitudinal direction of the metal tube P) It is being 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 truck 5 and moves forward and backward integrally with the traveling truck 5, and is also connected to the rear end of the rod portion 1 and expands and contracts in the longitudinal direction of the metal tube P. Specifically, the cylinder device 6 of this embodiment is an air cylinder device that includes a cylinder 61 and a piston rod 62 that moves relative to the cylinder 61, and the cylinder 61 is attached to a traveling truck and the piston A rod 62 is connected to the rear end of the rod 1.

The operation of applying resin to the inner surface of the metal tube P using the inner surface resin coating apparatus 100 having the above configuration will be described below.
FIG. 3 is a side view (a view viewed from the horizontal direction perpendicular to the longitudinal direction of the metal tube) schematically illustrating the outline of the operation of applying resin to the inner surface of the metal tube P by the inner surface resin coating device 100. FIG. 3(a) is a diagram showing the state when the contact portion 3 first contacts the tapered portion P12 of the metal tube P as the traveling trolley 5 moves, and FIG. FIG. 6 is a diagram showing a state in which the traveling trolley 5 has further moved from the state shown in (a), and the contact detection unit 4 has detected that the contact portion 3 has contacted the tapered portion P12.
When applying resin to the inner surface of the metal tube P using the inner surface resin coating device 100, the traveling cart 5 is moved from an initial state (a state before the rod portion 1 is inserted into the metal pipe P). , as shown in FIG. 3(a), the rod portion 1 moves toward the one tube end P1 side until the contact portion 3 contacts the tapered portion P12 on the one tube end P1 side of the metal tube P. . In the state shown in FIG. 3A, the jig 42 is in a position facing the proximity sensor 41, so the proximity sensor 41 detects that the jig 42 is close to the proximity sensor 41, as in the initial state. It remains as it is.

Next, even if the traveling trolley 5 tries to move further from the state shown in FIG. The position of the jig 42 does not change. On the other hand, when the traveling carriage 5 attempts to move further, the cylinder device 6 contracts (the cylinder 61 moves toward the piston rod 62), causing the traveling carriage 5 and the proximity sensor 41 to move forward. Since the position of the jig 42 does not change and the proximity sensor 41 moves, when the jig 42 comes out of the position facing the proximity sensor 41 as shown in FIG. Therefore, it is detected that the jig 42 is not close to the proximity sensor 41.
Therefore, by treating the time when it is detected that the jig 42 is not close to the proximity sensor 41 (the state shown in FIG. 3(b)) as the time when the contact part 3 contacts the tapered part P12, the contact part 3 It is possible to reliably detect that the contact point has come into 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 moved away from the position facing the proximity sensor 41 toward one pipe end P1, so that the contact portion 3 first contacts the tapered portion P12. It is also possible to adopt a mode in which the jig 42 is brought to a position facing the proximity sensor 41 by further moving the traveling trolley 5 after this. In this case, by treating the point in time when the jig 42 is detected to be close to the proximity sensor 41 as the point in time when the contact portion 3 contacts the tapered portion P12, the contact portion 3 contacts the tapered portion P12. This can be reliably detected.

Next, from the state shown in FIG. 3(b), while discharging resin from the resin discharging nozzle 2, the traveling trolley 5 is moved backward (moved to the right side in FIG. 3), so that the rod portion 1 is connected to the other pipe. It retreats toward the end P2 (see FIG. 1). By the resin discharge nozzle 2 reaching the tube end P2 while discharging the resin, it is possible to apply the resin to the entire inner surface of the metal tube P (excluding a part of the narrowed part P11 and the tapered part P12). It is.
Note that 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 coating of a desired 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 by, for example, using a variable traveling speed type as the traveling truck 5 and adjusting the traveling speed of the traveling truck 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 contacted the tapered portion P12. Therefore, by discharging resin from the resin discharging nozzle 2 after the contact part 3 contacts the tapered part P12, a part of the tapered part P12 and the straight part P13 (from the contact point 31 of the contact part 3 shown in FIG. 2 to the other It is possible to appropriately apply resin 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 side of the resin discharge nozzle 2 via a bearing, even if the resin discharge nozzle 2 rotates, the contact portion 3 is not contacted. The portion 3 remains stationary without rotating. 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 rod portion 1 is directed toward one pipe end P1 until the contact detection portion 4 detects that the contact portion 3 has contacted the tapered portion P12. After advancing, the resin is applied to the inner surface of the metal tube P by discharging resin from the resin discharge nozzle 2 while retracting toward the other tube end P2 side. That is, when resin is applied to the inner surface of the metal tube P, the resin discharge nozzle 2 and the rod portion 1 retreat from one tube end P1 side toward the other tube end P2 side. In other words, when the resin is applied to the inner surface of the metal tube P, the rod portion 1 is located downstream of the resin discharge nozzle 2 in the moving direction. Therefore, there is no risk that the guide part 9 and the rod part 1 will come into contact with the inner surface of the metal tube P after the resin has been applied by the resin discharge nozzle 2, and the resin applied to the inner surface will not come into contact with the guide part 9 or the rod part. There is no risk of peeling off due to contact with 1.
However, the present invention is not limited to this, and adopts a mode in which the resin is discharged from the resin discharge nozzle 2 immediately after the rod portion 1 is inserted, and the resin discharge is stopped when the contact portion 3 contacts the tapered portion P12. It is also possible to do so.

Although the present embodiment has been described using an example in which the contact portion 3 is attached to the distal end side of the resin discharge nozzle 2, the present invention is not limited to this.
FIG. 4 is a side cross-sectional view (a cross-sectional view viewed from the horizontal direction orthogonal to the longitudinal direction of the metal tube P) schematically showing the schematic configuration of a modified example of the contact portion. FIG. 4(a) shows a state in which the contact portion is in contact with the tapered portion P12 of the metal tube P, and FIG. 4(b) shows a state in which resin has started to be discharged from the resin discharge nozzle 2. It is a diagram. The broken line arrow shown in FIG. 4(b) means the resin discharge direction.
As shown in FIG. 4, the contact portion 3A according to the modification is attached to the rod portion 1 on the rear end side of the resin discharge nozzle 2 (on the other end P2 side of the metal tube P). Specifically, in the example shown in FIG. 4, among the plurality of guide parts 9, the guide part 9 located closest to the tip side functions as the contact part 3A. As mentioned 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, the diameter of at least the most distal guide portion 9 is made larger than the inner diameter D2 (see FIG. 2) of the orifice constriction portion P11, and the diameter (maximum diameter) of the resin discharge nozzle 2 is set to be the inner diameter of the orifice constriction portion P11. By making it smaller than D2, it is possible to cause the guide portion 9 closest to the tip side to function as the contact portion 3A. The contact portion 3A according to the modification is particularly effective when the difference between the inner diameter D2 of the aperture opening 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 constriction portion P11 and smaller than the diameter of the guide portion 9. However, if the difference between the inner diameter D2 of the aperture drawing part P11 and the inner diameter D3 of the straight part is small, the difference between the inner diameter D2 of the aperture drawing part P11 and the diameter of the guide part 9 becomes even smaller. This is because the selectable range becomes considerably small.

As shown in FIG. 4(a), by moving the traveling cart 5 (see FIG. 1) (move it to the left side in FIG. 4), the contact portion 3A contacts the tapered portion P12 of the metal tube P at the contact point 31A. The contact detection section 4 can detect that the contact state has been reached, as in the case of the contact section 3 described above.
Then, from the state shown in FIG. 4(a), by retracting the traveling cart 5 (see FIG. 1) (moving it to the right side in FIG. 4), the rod portion 1 is moved to the other pipe end P2 (see FIG. 1). At the timing when 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 shown in FIG. 4(b). It is only necessary to start discharging the resin from the resin discharging nozzle 2 as shown in FIG. By causing the resin discharge nozzle 2 to reach the tube end P2 while discharging the resin, it is possible to apply the resin to the entire inner surface of the metal tube P (excluding a part of the narrowed part P11 and the tapered part P12). It is. Note that the timing at which the resin discharge nozzle 2 starts discharging the resin (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 timing at which the resin discharge nozzle 2 starts discharging the resin. It can be determined in advance according to the distance between the contact portion 3A and the resin discharge direction.

Further, in this embodiment, a configuration has been described in which the contact detection section 4 includes the proximity sensor 41 and the jig 42, but the present invention is not limited to this. For example, it is also possible to use a pressure sensor attached to the tip side of the contact portion 3 as the contact detection portion. In this case, when the pressure detected by the pressure sensor exceeds a predetermined threshold value, it is possible to detect that the contact portion 3 has contacted the tapered portion P12.

Although a detailed description will be omitted, for example, the metal tube P before cold drawing is sequentially conveyed in its longitudinal direction or in a horizontal direction perpendicular to the longitudinal direction, while being transferred to a heating device (not shown). , resin is applied to the outer surface by an outer resin coating device (not shown), resin is applied to the inner surface by the inner resin coating device 100, and air is blown onto the inner surface by a blower device (not shown). preferable. Then, after the resin coated on the outer and inner surfaces of the metal tube P dries and a resin coating is formed on the outer and inner surfaces of the metal tube P, the metal tube P is transported to a drawing machine that performs a cold drawing process. For example, seizure during cold drawing can be efficiently prevented.

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

Claims (3)

An inner surface resin coating device that coats a lubricating resin on the inner surface of a metal tube before cold drawing,
The metal tube includes, in order from one tube end, a constricted portion, a tapered portion connected to the constricted portion and tapered in diameter toward the tube end, and a tapered portion connected to the tapered portion and having a constant diameter. a straight portion having a straight portion;
The inner surface resin coating device includes:
a rod that is inserted into the metal tube from the other end of the metal tube and moves forward and backward in the longitudinal direction of the metal tube;
a resin discharge nozzle that is attached to the tip of the rod and discharges resin onto the inner surface of the metal tube;
It is attached to the tip side of the resin discharge nozzle or attached to the rod part at the rear end side of the resin discharge nozzle, and has dimensions larger than the inner diameter of the mouth constriction part and smaller than the inner diameter of the straight part. a contact portion capable of contacting the tapered portion;
a contact detection section that detects that the contact section has contacted the tapered section;
a traveling trolley that moves forward and backward in the longitudinal direction of the metal pipe;
a cylinder device that is attached to the traveling truck and moves forward and backward integrally with the traveling truck, and that is connected to the rear end of the rod portion and expands and contracts in the longitudinal direction of the metal tube;
The contact detection section is
a proximity sensor that is attached to the traveling truck and moves forward and backward integrally with the traveling truck;
a jig that is attached to the rear end of the rod and allows the proximity sensor to detect whether or not the jig is close to the proximity sensor;
Equipment for applying resin on the inner surface of metal pipes. The resin discharge nozzle is a bell cup nozzle that rotates around the central axis of the rod,
The contact portion is attached to the tip side of the resin discharge nozzle via a bearing.
The apparatus for applying resin on the inner surface of a metal tube according to claim 1 . After the rod portion moves toward the one tube end until the contact detection portion detects that the contact portion has contacted the tapered portion, the rod portion moves toward the other tube end. The resin is configured to be applied to the inner surface of the metal tube by discharging the resin from the resin discharge nozzle while retracting toward the metal tube.
The apparatus for applying resin on the inner surface of a metal tube according to claim 1 or 2 .

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