KR20120020404A - Mandrel for bending of tube - Google Patents

Abstract

There is provided a mandrel for tube bending, which is used for tube bending, in particular tube processing into hydroforming products.
The tube bending mandrel includes: a mandrel body inserted into and moved in a tube to be bent; and one or more tube guide means connected to one side of the mandrel body and provided to support a bending portion of the tube; And lubricant processing means provided to enable the supply of lubricant between the mandrel and the tube and the recovery of the supplied lubricant through the mandrel body.
According to the present invention, it is possible to effectively prevent friction (wear) between the mandrel and the tube (inner surface) by improving the lubricity of the lubricant (lubricating oil), and in particular, to recover (easily) recover the total amount of the supplied lubricant. Improved reusability also prevents contamination of the surrounding equipment or environment by leaking lubricants, while improving the effectiveness of removing foreign matter in the tube when using the mandrel.

Description

Mandrel for tube bending {Mandrel for Bending of Tube}

The present invention relates to a tube bending mandrel used for bending a tube, in particular a tube processed into a hydroforming product, and more particularly between the mandrel and the tube (inner surface) through improved lubricity of lubricant (lubricating oil or oil) In addition to effectively preventing friction, it is also possible to recover the total amount of lubricant supplied, thereby improving oil recyclability and preventing surrounding equipment or environmental pollution by leaking oil. And a mandrel device for tube bending.

Hydro-Forming is one of the special processing methods of mechanical sheet metal that is formed at room temperature (10 ℃ ~ 30 ℃) and expands the tube (tube) by using hydraulic pressure. Hydraulic molding '.

This hydroforming technology is used to make parts manufactured by welding, etc. in a simple process, that is, seam welded (or resistance welded) tubes, and both ends of the tubes are punched and sealed inside the tubes. It is a technique of forming into a desired shape by raising the pressure (water pressure) of the pipe liquid.

In recent years, such a hydroforming technology is typically used in the automotive industry, which provides advantages such as the reduction of molding costs and the reduction of molding cost of press products made of a combination of large and small unit panels such as front side members and bumpers. do. Hydroforming also offers process advantages such as good shape precision of the part, integration of components, and elimination of welds that can cause defects.

In other words, the known hydroforming technology uses a simpler process of producing parts that have been produced by conventional stepping and welding, that is, a tube (pipe) that is made of a seam (or resistance welded) tube (pipe). Pipe) It is a technology of forming into a desired shape by increasing the water pressure inside the pipe while sealing both ends with a punch.

However, in order to produce such a hydroforming product, a bending operation of a hydroforming tube is first performed to form a tube shape of a desired shape, and then the bent tube is seated on a mold, and a high-pressure expansion liquid is produced. It is supplied inside the tube to produce a hydroforming product.

For example, the bending process for seating the tube in the mold is a very important process in the hydroforming process, because if the tube is not bent precisely, the tube cannot be seated correctly in the mold, resulting in product defects. Because.

On the other hand, in order to prevent the bending portion of the tube bent and bent when bending such a tube, although not shown in a separate drawing, while inserting a mandrel into the tube, and connected to the connecting rod, etc. in the tube, in particular, the tube It is to be in close contact with the inner diameter of the tube at the bending part to prevent the inner side during the bending of the tube.

At this time, lubricating oil is supplied and ejected between the mandrel and the tube through the mandrel so as not to cause excessive friction or wear between the mandrel and the inner surface of the tube.

However, in the conventional case, the lubricant is simply ejected toward the inner surface of the tube through the connecting rod and the mandrel to reduce the friction between the mandrel and the tube when the tube is bent, so that the friction between the mandrel and the tube is somewhat reduced. As it leaks along the tube, there has been a problem of inviting pollution of the surrounding equipment or workplace by the leaking lubricant, for example, environmental pollution.

In particular, since the lubricant is simply ejected from the mandrel, the lubricant is not evenly distributed throughout, resulting in concentrated (local) friction or wear between the actual mandrel and the tube, resulting in severe bending or severe tube movement during the mandrel. It causes problems such as cutting.

In particular, the leaked lubricating oil caused the malfunction of the automation equipment, and the oil remaining inside the tube was not completely removed, resulting in processing defects during the forming of the tube, that is, hydroforming.

The present invention has been proposed in order to solve the conventional problems as described above, the object of the present invention is to effectively prevent friction (wear) between the mandrel and the tube (inner surface), in particular, by improving the lubricity of the lubricant (lubricating oil) Provides a mandrel device for tube bending that makes it possible (easily) to recover the total amount of lubricating oil, improves recyclability of the lubricating oil, prevents surrounding equipment or environmental pollution caused by leaked lubricating oil, and also removes foreign substances in the tube when using the mandrel. It's there.

The present invention as a technical configuration for achieving the above object, the mandrel body is inserted into the tube to be bent to move;

At least one tube guide means associated with one side of the mandrel body and provided to support a bending portion of the tube;

Lubricant processing means provided to enable the supply of lubricant between the mandrel and the tube and the recovery of the supplied lubricant through the mandrel body;

It provides a mandrel for tube bending comprising a.

Preferably, the tube guide means is rotatably assembled to support the tube bent to the connecting body assembled on one side of the mandrel body, the other side of the mantrel body is connected to the connecting rod for movement in the tube of the mandrel body do.

More preferably, the tube guide means includes a tube support ring for supporting the inner diameter of the tube, and an assembly assembled inside the tube support ring and rotatably assembled to the connecting member or another assembly, The assembly and the other assembly and the connection body is provided with a projection assembly groove in which the circular projection provided in the assembly is rotatably assembled.

In addition, the lubricant processing means includes an oil supply hole and an oil recovery hole provided in the tube support ring of the mandrel body and the tube support means to enable the in-tube supply and recovery of the lubricant, In the tube support ring of the mandrel body and the tube guide means to the outside of the recovery hole, oil sealing holes provided to limit the distribution area of the lubricant are further provided.

Preferably, the oil supply hole is configured to communicate with the oil supply portion of the connecting pipe assembled to the mandrel body, while the lubricant recovery hole is an assembly or connecting body different from the tube support ring and the assembly of the tube supporting means. It is configured to communicate with the lubricant recovery passage formed in the.

More preferably, the lubricant recovery passage is in communication with a connection pipe connected to the mandrel body and a discharge pipe inserted through the fastening bolt for assembling the mandrel body of the connection to allow external recovery of oil.

More preferably, the assembly of the mandrel body and the assembly assembled to the tube support ring of the tube guide means is divided and assembled inside the tube support ring and the mantrel body, and the assembly carries a fixing ring to the tube support ring. Is assembled.

According to the present invention as described above, the lubricant (lubricating oil) can be uniformly distributed and supplied to the inside of the tube, thereby improving the lubricity between the mandrel and the inner surface of the tube and effectively preventing their friction (wear). It is therefore possible to improve its formability during tube bending.

In addition, the present invention improves the reusability of the lubricating oil through the (whole quantity) recovery of the lubricant used in the use of the mandrel, and enables the removal of contaminants in the tube, thereby improving the tube workability through the clean environment of the tube.

In particular, the present invention is to provide an environmentally friendly mandrel to prevent the installation or environmental pollution caused by the external leakage of lubricating oil.

After all, the present invention is to provide a number of excellent effects compared to the conventional.

1 is an overall configuration diagram showing a mandrel for tube bending according to the present invention,
Figure 2 is an assembled state diagram showing the present invention mandrel of Figure 1,
Figure 3 is an exploded perspective view of the mandrel of the present invention of Figure 2,
Figure 4 is an operating state diagram showing the invention mandrel of Figures 1 to 3,
5A and 5B are photographs showing tube bending facilities using the mandrel of the present invention.

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

First, FIGS. 1 to 4 show a mandrel 1 for tube bending according to the present invention, and FIGS. 5A and 5B show a tube bending facility using the mandrel of the present invention as a photograph. . In addition, below, a lubricant is demonstrated as lubricating oil, ie, the supply lubricating oil 2 and the recovered lubricating oil 2 '.

For example, as shown in Figs. 1 to 3, the mandrel for tube bandine 1 of the present invention, as a preferred embodiment, the mandrel body 30 is inserted into the tube 10 to be bent and moved, and the mandrel body One or more tube guide means 50 provided to be supported while moving the tube bending portion in connection with one side of the 30 and a lubricating oil distribution region T (envelope region) supplied between the tubes through the mandrel body 30. It can be configured to include a lubricating oil processing means (70) provided to enable the recovery (external recovery) of the supplied lubricating oil while defining a).

Accordingly, the mandrel 1 of the present invention is described in detail below with reference to FIG. 4, when the mandrel body 30 is pre-bended of a tube processed through a processing, for example, hydroforming, the tube 10. Of the tube on which one or more, preferably at least two, associated tube guide means 50 associated with one side of the mandrel body, for example, the front side, are bent while moving within the tube while the tube is being bent. The inner diameter portion is closely supported to prevent the tube from bending when the tube is bent.

Particularly, in the case of the mandrel 1 of the present invention, since the lubricant processing means 70 described in detail below is included, the tube guide means 50 and the tube that support the tube, particularly when the tube is bent through the mandrel, are described. The lubricating oil 2 supplied so as to be evenly distributed between the inner diameter parts suppresses severe wear and friction between the mandrel element (part) (tube support means) and the inner diameter part of the tube.

As a result, the mandrel of the present invention enables a more uniform lubricating oil distribution as compared to simply ejecting lubricating oil between the mandrel and the tube.

Furthermore, since the lubricating oil processing means 70 of the present invention recovers almost the entire amount of the lubricating oil 2 ejected between the mandrel and the tube, and enables the recycling of the recovered lubricating oil 2 ', the lubricating oil has previously been separated from the mandrel. It is to prevent leakage (leak) between the tubes.

Accordingly, the mandrel of the present invention enables uniform and sufficient lubricating oil distribution (coating), especially in the bending part where the mandrel and the tube are in close contact with each other, and at the same time, it is possible to smoothly recover the ejected lubricating oil, thereby lubricating oil and leaking lubricating oil. It also prevents pollution of surrounding equipment and environment.

For example, FIG. 5A and FIG. 5B show photographs of a bending facility of a tube in which the mandrel 1 of the present invention is used, in particular a bending facility of a tube 10 which is a hydroforming material.

That is, in the photograph of FIG. 5, reference numeral 101 is a clamp for applying a force to fix and bend the tube, 102 is a rotational axis, and 103 is a support. At this time, the mandrel 1 is inserted into the tube as in 5a.

Accordingly, when the tube is bent through the tube bending facility, the mandrel 1 moves inside the tube, and the mandrel of the present invention supplies and recovers lubricating oil through the lubricating oil processing means 70 described in detail below. To make it possible.

Hereinafter, in the mandrel 1 for tube bending of the present embodiment, the mandrel body 30, the mandrel guide means 50, and the lubricating oil treatment means 70, which are main components, will be described in detail with reference to the drawings.

First, Figures 1 to 3 show the mandrel body 30 of the mandrel for tube bandage 1 according to the present invention, the mandrel body 30 of the present invention is formed of a cylindrical metal material as a whole Preferably, it is formed of a copper material or the like to prevent tube damage when the tube contacts.

In addition, one side (front side) of the mandrel body 30 is formed with a connector assembly groove 30b to which the connecting body 32 is assembled, and the connecting rod 34 on the other side (rear side) of the mandrel body 30. The connecting rod fastening groove 30a to which the screw S is coupled is formed.

In addition, the mandrel body 30 is formed to have a tolerance with the inner diameter of the tube 10 as a whole, which is the actual mandrel body has a length, the support of the inner diameter of the tube so that the bending portion is not bent when bending the tube Since the tube guide means 50 will be described in detail below, the mandrel body is preferably formed with a smaller diameter than the inner diameter of the tube, so that the movement inside the tube is free.

On the other hand, the connecting body 32 is assembled in one side of the mandrel body 30, the tube guide means 50 to be described in detail below is assembled to be rotatable, for this purpose, as shown in FIG. The connecting body 32 is formed in a cylindrical body, and two divided connecting members are compressed to be inserted into the connecting assembly assembly groove 30b of the mandrel body.

In this case, as shown in FIGS. 1 and 3, the connecting body 32 includes a fastening bolt 33 inserted through the other connecting rod fastening groove 30a of the mandrel body 30 through the center of the mandrel body. It is screwed through a hole (unsigned) and is firmly assembled inside the mandrel body. Of course, the screw portion (S) for screwing the fastening bolt is formed on the rear side of the connecting assembly is divided.

Accordingly, the mandrel body 30 of the present invention, as shown in Figs. 1 to 3, the connecting rod 32 and the connecting rod 34 to which the tube guide means 50 moving while substantially supporting the tube bending portion is connected. ) Is assembled or connected inside the body on one side and the other side, respectively, and is moved inside the tube through the connecting rod.

On the other hand, the connecting rod 34 is a hollow pipe inside the lubricating oil supply passage 34a between the discharge pipe and the connecting rod while passing through the discharge pipe 80 through which the recovery lubricating oil 2 described in detail below passes through the inner hollow portion. Will be formed.

Next, as shown in Figures 1 to 3, the tube guide means 50 of the mandrel of the present invention to prevent the tube from being bent at the inner diameter portion of the tube 10 during tube bending, the tube inner diameter portion A support tube support ring 52 and an assembly 54 assembled inside the tube support ring and rotatably assembled to the connector 32 or another assembly.

That is, as shown in Figures 1 to 3, in this embodiment, the mandrel is provided with two tube guide means 50, the first tube guide means 50 is the connecting body of the mandrel body 30 A third tube guide means 50 is associated with the first tube guide means 50.

Of course, in the present embodiment there is a difference in the arrangement of the tube guide means, but the configuration is the same, and it will be described with the same reference numeral 50, in this embodiment is shown as using two tube guide means in this embodiment, but is not necessarily limited thereto. There is no problem in using more than three tube guide means in conjunction.

However, it is not necessary to use the tube guide means more than necessary, and it is preferable to arrange it properly in consideration of the diameter of the tube, the bending angle, etc., in order to support the static bending of the bending part at the inside of the tube when bending. Will be used in conjunction with at least two tube guide means.

Therefore, in this embodiment, it will be described that the two tube guide means used in conjunction.

1 and 3, circular protrusions 56 are integrally formed on one side of the assemblies 54 of the first and second tube guide means 50, and the circular protrusions 56 are formed. Circular protrusion assembly grooves 58 into which the grooves are inserted are integrally formed in the assembly 54 and the connecting body 32 of the second tube guide means 50.

Thus, the circular projections of the assemblies are inserted into the corresponding assembly assembly 54 and the projection assembly grooves 58 of the connector 32, but the separation is prevented and enables the circular motion.

In addition, although the bending state of the tube is not illustrated in FIG. 1, the assemblies 54 of the tube guide means 50 during the bending of the tube may be bent at the time of bending the tube while being in a circular motion (upward and downward turning movement) according to the tube bending angle. Support the site.

On the other hand, the assembly 54 and the connector 32 is provided in a two-divided assembly structure, except for at least the assembly 54 of the first tube guide means 50 at the tip side, the second tube guide means ( The assembly 54 of 50 and the connector 32 as described above are assembled in a two split assembly structure.

That is, in order to be fastened so that the circular protrusion does not leave the protrusion assembly groove, the circular protrusion is inserted into the divided protrusion assembly groove, and in this state, the split pieces (elements) are pressed and assembled so that the circular protrusion is separated from the protrusion assembly groove. Is prevented.

1 and 3, the assembly 54 is a tube support ring through a fixing ring 60 fitted into a groove (unsigned) formed in the inner diameter of the tube support ring 52 ( 52) can be fixed to the assembly.

On the other hand, since the tube support ring 52 substantially supports the inner diameter of the tube so that the bending portion is not bent, an appropriate tolerance between the tubes, ie, excessive contact with the inner diameter of the tube when the mandrel moves, is excessively worn (friction). It is formed to a diameter having a suitable tolerance so that does not occur.

In addition, it is preferable that the corner portions of the tube support rings 52 of the tube guide means 50 are curved so that the corner portions do not damage the inner diameter of the tube.

For example, if the edge of the tube support ring is not curved to damage the inner diameter (inner surface) of the tube, hydroforming may lead to product defects in which the damaged portion bursts due to hydraulic pressure.

Therefore, as shown in Figures 1 to 3, in the tube guide means 50 of the present invention, through the tube support ring 52 for supporting the inner diameter of the tube, the tube using the tube bending equipment as shown in FIG. When bending the bending portion is not bent or crushed, such tube support rings are assembled in a rotatable connection through the assembly 54 and the connecting body 32 of the mandrel body side.

Next, Figures 1 to 3 show the lubricant processing means 70 to solve the problems of the existing lubricant leakage or waste in the tube bending mandrel (1) of the present invention.

That is, as shown in Figs. 3 and 4, the lubricating oil processing means 70 of the present invention basically enables the supply of the lubricating oil 2 between the mandrel and the tube to the inside of the tube, and in particular, is supplied and ejected. It is possible to recover the recovered lubricating oil (recovery lubricating oil 2 ').

Therefore, since it is possible to recover the lubricating oil, waste of lubricating oil by simply ejecting the lubricating oil through the mandrel between the mandrel and the tube, the contamination of the lubricating oil to the surroundings or the residue of foreign substances due to the lubricating oil residue inside the tube, etc. The problem can be effectively eliminated in the present invention.

At this time, in the mandling of the present invention, the tube support ring 52 of the mandrel body 30 and the tube support means 50 is a lubricant supply hole 72 and a lubricant recovery hole 74 for supply and recovery of lubricant. ) Is formed.

That is, as shown in FIGS. 1 and 2, the lubricating oil supply hole 72 communicates with the other connecting rod fastening assembly groove 30b of the mandrel body 30 and is integrally spaced along the recessed groove portion 72a of the mandrel body. It is formed through.

Therefore, as shown in FIGS. 1 and 4, the lubricating oil 2 supplied to the outside of the discharge pipe 80 through the inner lubricating oil supply space 34a of the connecting rod 34 is connected to the lubricating oil supply hole 72. Squirt.

Then, the supplied lubricant is recovered through the lubricant recovery hole 74 formed in the tube support ring 52 as shown in FIG.

In this case, the mandrel body 30 and the tube support ring 52, in particular, the foremost tube support ring 52, the lubricant sealing hole 76, that is, the lubricant packing is further provided, as shown in FIG. Sealing hole assembly grooves (not shown) to which the lubricant sealing holes 76 of the packing member are assembled are formed on the outer surface of the other side of the cylindrical mandrel body 30 and the outer surface of the tube support ring 52 of the first tube guide means. Formed integrally, the lubricant seals are assembled.

Such lubricant sealing holes 76 are arranged so that the parts (annular contact ends (unsigned)) facing each other face each other so as to face each other, so that the lubricant distribution region T is formed and maintained as a closed space between the sealing holes. It is desirable to.

Therefore, the one side sealing hole on the side of the mandrel body removes the remaining foreign matter on the inner surface of the tube when the mandrel moves out of the tube and moves out when the tube is bent, and the sealing hole on the support ring side prevents the lubricant from remaining in the inner diameter of the tube in the lubricating oil distribution area. It moves in close contact with the inner surface of the tube.

Of course, the intertube wear of the sealing holes occurs during the movement of the mandrel, but the actual speed of movement of the mandrel is not made very high, and at present, wear-resistant seals, that is, packing members are known.

Therefore, as shown in Fig. 4, a sufficient lubrication film is defined between the front tube support ring 52 and the lubricating oil sealing hole 76 provided on the rear mandrel body 30 to surround (enclose) the lubricating oil distribution area T. At the same time, the sealing holes are brought into close contact with the inner diameter of the tube while the movement of the mandrel allows the foreign substances remaining on the inner surface of the tube to be drawn out and removed together with the removal of the mandrel from the tube. The lubricant distribution area is formed during the movement of the mandrel for recovery, and the inner surface of the tube can be cleaned.

That is, since the distribution area (T) between the lubricating oil sealing holes corresponds to a portion of the tube support ring and the mandrel body, the lubricating oil is sufficiently ejected and distributed between the tube and the mandrel, so that the tube and the mandrel do not leak outside as before. It is to effectively suppress the wear of the liver.

Of course, such maintenance of the lubricating oil distribution area T is possible because the lubricating oil can be recovered through the lubricating oil processing means 70 of the present invention.

At this time, as shown in Figure 3 and 4, the lubricant recovery hole 74 of the present invention, the tube support ring 52 and the assembly 54 and the other assembly or connecting body 32 of the tube support means The lubricating oil can be smoothly recovered externally through the discharge pipe 80 which is in communication with the lubricating oil recovery passage 78 formed in the screw, and thus screwed to the connecting body 32.

That is, as shown in Figures 1 and 4, the lubricating oil recovery passage 78, specifically, the support ring recovery passage 78a formed in the tube support ring 72 and the assembly assembled to the support ring ( And vertical and horizontal recovery passages 78b and 78c formed at 54 and a connector recovery passage 78d formed at connector 32.

At this time, in the present embodiment, the support ring 52 of the foremost first tube guide means is formed with vertical and horizontal recovery passages 78b and 78c, but is connected between the first support ring and the connecting beam. Of course, only the horizontal recovery passageway 78c is formed in the assembly 54 of the tube guide means 50 of the two, and each of the recovery passageways, as well as should be adjusted in advance to a position in communication with each other.

Therefore, as shown by a straight arrow (supply lubricant 2) and a dotted arrow (recovery lubricant 2 ') in FIG. 4, the lubricant is supplied to the lubricant supply space 34a of the connecting rod 34 connected to the hose through an external pump or the like. )-> Inside the mandrel body-> Supply hole 72-> Lube oil distribution area (T) between the lubricant sealing holes 76-> Recovery hole 74 of the tube support ring 52-> Tube support ring + assembly Recovery passage 78 of the other assembly + connector-> the discharge pipe 80 passes through the inner hole 33a of the fastening bolt 33 and passes through the connecting rod 34.

As a result, the tube bending mandrel 1 of the present invention is uniformly distributed while smoothly supporting the inner diameter of the tube being bent through the tube support ring 52 through the supply of lubricating oil and the uniform distribution region T and recovery. By applying sufficient lubricating oil in the uniform distribution area, the friction between the mandrel, the tube support ring, and the tube is not generated, and almost all of the supplied lubricating oil is recovered to prevent waste of lubricant or contamination by lubricating oil while leaking to the surroundings. And it is possible to improve the cleanliness of the inner surface of the tube through the removal of foreign matter.

That is, the mandrel 1 for tube bending of the present invention improves product quality by preventing processing defects during hydroforming of the tube.

While the invention has been shown and described in connection with specific embodiments so far, it will be appreciated that the invention can be varied and modified without departing from the spirit or scope of the invention as set forth in the claims below. It will be appreciated that those skilled in the art can easily know.

1 .... Mandrel for tube bending 10 .... Tube
30 .... Mandrel Body 32 .... Connecting Body
34 .. Connecting rod 50 .... Tube guide means
52 .... Tube Support Ring 54 .... Assembly
56 .. Circular projection 58 .... projection assembly groove
70 .... Lubricant treatment means 72 .... Lubricant supply holes
74 .... Lubricant return hole 76 .... Lubricant sealing hole
78 .... Lubricant recovery channel

Claims (7)

A mandrel body 30 inserted into and moved into the tube 10 to be bent;
One or more tube guide means (50) connected to one side of the mandrel body (30) and provided to support a bending portion of the tube; And,
Lubricant processing means (70) provided to enable the supply of lubricant between the mandrel and the tube and the recovery of the supplied lubricant through the mandrel body (30);
Mandrel for tube bending comprising a.
The method of claim 1,
The tube guide means 50 is assembled to be rotatable to support the tube bent to the connecting body 32 is assembled on one side of the mandrel body 30,
Mandrel for tube bending, characterized in that the other side of the mantrel body 30 is connected to the connecting rod 34 for moving in the tube of the mandrel.
The method of claim 2,
The tube guide means 50, the tube support ring 52 for supporting the inner diameter of the tube, an assembly which is assembled inside the tube support ring, rotatably assembled to the connecting body 32 or other assembly ( 54),
The assembly 54 and the other assembly and the connector 32, the mandrel for tube bending, characterized in that provided with a projection assembly groove (58) for rotatably assembling the circular projection (56) provided in the assembly.
The method according to any one of claims 1 to 3,
The lubricant processing means 70 is a lubricant supply and recovery hole 72 provided in the tube support ring 52 of the mandrel body 30 and the tube support means 50 to enable the supply and recovery of the lubricant in the tube. (74),
Sealing holes 76 provided to form a lubricant distribution region T are formed in the tube support ring 52 of the mandrel body 30 and the tube guide means outside the lubricant supply and recovery holes 72 and 74. Mandrel for tube bending, characterized in that further installed.
The method of claim 4, wherein
The lubricant supply hole 72 is configured to communicate with the lubricant supply portion 34a of the connecting pipe 34 assembled to the mandrel body 30,
The lubricant recovery hole 74 is configured to communicate with the lubricant recovery passageway 78 formed in the tube support ring 52 and the assembly 54 and the other assembly or connecting body 32 of the tube support means. Mandrel for tube bending.
The method of claim 5,
The lubricant return passage 78, the discharge pipe is inserted to allow the recovery of the lubricant through the connection pipe 34 connected to the mandrel body, and the fastening bolt 33 for assembling the mandrel body of the connector 32. Mandrel for tube bending, characterized in that the communication with the 80.
The method of claim 5,
The assembly 54 of the tube support ring 52 of the tube guide means and the connecting body 32 of the mandrel body are divided and assembled into the tube support ring 52 and the mantrel body 30.
The assembly (54) is a mandrel for tube bending, characterized in that the assembly via the fixing ring (60) to the tube support ring.

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