JP5661494B2 - Metal tube drawing method and drawing apparatus - Google Patents

Description

  The present invention relates to a metal tube drawing method and drawing apparatus that can be used as an OPC photosensitive drum substrate suitably used in an electrophotographic apparatus such as a copying machine, a laser beam printer, and a facsimile machine and that can produce a drawing pipe having excellent dimensional accuracy.

  In the description of the present specification, in the drawing method and drawing apparatus, “rear” represents the direction on the raw tube side relative to the drawn tube, and “front” represents the direction on the drawn tube side relative to the raw tube. .

  In recent years, non-cutting tubes suitable for mass production have been frequently used as substrates for OPC photosensitive drums in electrophotographic apparatuses such as copying machines, laser beam printers, and facsimiles. One of the non-cut pipes is an ED pipe made by drawing an extruded aluminum pipe, which is suitable for mass production in that multiple product pipes can be produced by one drawing, and responds to mass consumption as the market expands. It is attracting attention as a manufacturing method.

  This ED pipe is obtained by first extruding an aluminum billet to obtain an aluminum extruded element pipe, cutting the extruded element pipe into a predetermined length, and performing a drawing process of one pass or two passes or more with a die and a plug, It is manufactured by obtaining an aluminum tube defined in a predetermined shape (outer diameter, inner diameter, wall thickness), then cutting, chamfering and cleaning the end, and inspecting the dimensions and appearance.

  In such a drawing process for an aluminum tube for a photosensitive drum substrate, a drawing device has been proposed for obtaining a high degree of surface smoothness and dimensional accuracy, particularly tube accuracy (Patent Documents 1 and 2). Moreover, in order to improve dimensional accuracy, continuous drawing of two or more passes may be performed.

  The drawing die described in Patent Document 1 defines a die approach angle and a bearing length in order to achieve a high degree of surface smoothness. Further, the drawing machine described in Patent Document 2 has a structure that supports a rod rod that supports a plug for forming an inner surface so as not to be bent during drawing.

Japanese Examined Patent Publication No. 4-13044 JP-A-9-29324

  However, as described above, the ED pipe manufactured through many processes includes many variation elements such as the billet component when extruding the raw pipe, the outer diameter, the wall thickness, and the hardness of the extruded raw pipe. It was not easy to improve dimensional accuracy and surface quality.

  In the first place, drawing to improve the dimensional accuracy of the extruded tube is known, and drawing is performed in many product manufacturing. In this case, in order to prevent the seizure of the pipe, the lubricating oil is supplied in advance by pouring the lubricating oil into the pipe inclined with respect to the inner face of the pipe and applying the lubricating oil to the outer face in advance. The method or the method of flowing down lubricating oil at any time during the drawing process has been adopted.

  However, in the case where a long elementary tube such as an ED tube for a photosensitive drum substrate is continuously pulled out at a high speed for two or more passes, it is difficult to flow lubricating oil into the inner surface of the tube in advance. For this reason, lubricating oil must be applied to the plug, inserted into the base tube, and then pulled out as it is. In such a drawing method, the outer surface can be supplied with lubricating oil at any time, while the inner surface may be seized due to insufficient lubricating oil during drawing. In other words, the lubricating oil adhering to the inner surface of the raw pipe rises in the vicinity of the plug due to the heat of drawing processing and the viscosity decreases. The upper region of the inner surface of the base tube is easily depleted of lubricating oil, and seizure may occur. When seizure occurs, not only scratches are generated, but also the processing heat reduces the dimensional accuracy. Lubricating oil shortage is more likely to occur as the length of the pipe is longer and the drawing speed is faster. Therefore, to increase the productivity of the ED pipe by drawing the long pipe at high speed, it is necessary to overcome the seizure of the inner surface. It has become a challenge.

  The present invention has been made in view of such a technical background, and provides a metal pipe drawing method and drawing apparatus capable of reliably attaching lubricating oil to the inner surface of the pipe during drawing and preventing seizure. The purpose is to do.

  In order to achieve the above object, the present invention provides the following means.

[1] In a method of drawing a metal tube, the metal tube is drawn by passing it between a die for forming the outer surface and a plug for forming the inner surface.
When the lubricating oil adheres to the inner surface of the raw pipe before passing through the bearing portion of the plug, the lubricating oil adheres to at least a part of the upper half area of the inner face of the raw pipe and the lower surface of the inner face of the raw pipe. A method of pulling out a metal tube, wherein selective adhesion is performed so that lubricating oil does not adhere to a half region.

  [2] A discharge port is provided in a lower half region of the hollow rod that supports the plug, a nozzle that protrudes from the outer peripheral surface of the rod is provided in the discharge port, and the tip of the nozzle is opened substantially upward. Then, by supplying the lubricating oil into the rod and discharging the lubricating oil from the tip opening of the nozzle, the lubricating oil adheres to at least a part of the upper half area of the inner surface of the element tube and the element 2. The method of pulling out a metal tube according to item 1 above, wherein the selective adhesion that does not allow the lubricant to adhere to the lower half region on the inner surface of the tube is performed.

  [3] The metal tube drawing method according to the above item 2, wherein the distance between the tip opening of the nozzle and the bearing portion of the plug in the drawing direction is 20 cm or less.

  [4] From when the plug and the hollow rod are inserted into the inside of the element tube until the element tube is inserted through the die and set, the upper half area of the inner surface of the element tube 4. The metal according to any one of the preceding items 1 to 3, wherein the lubricant is adhered to at least a part and selective adhesion is performed so that the lubricant does not adhere to the lower half region of the inner surface of the base tube. How to pull out the tube.

[5] During the insertion operation of inserting the plug and the hollow rod into the inner tube, the lubricating oil is supplied into the plug and discharged from the discharge port provided at the tip of the plug. By
Lubricating oil adheres to at least a part of the upper half region on the inner surface of the raw tube and the lower half region on the inner surface of the raw tube until the raw tube is inserted through the die and set. 4. The method for pulling out a metal tube according to any one of items 1 to 3, wherein the selective adhesion without adhering the lubricating oil is performed.

[6] In a drawing apparatus for drawing a metal element tube by passing it between a die for forming the outer surface and a plug for forming the inner surface,
A discharge port is provided in a lower half region of the hollow rod that supports the plug, a nozzle that protrudes from the outer peripheral surface of the rod is provided in the discharge port, and a tip of the nozzle opens substantially upward. A metal tube drawing apparatus characterized by that.

[7] In a drawing apparatus for drawing a metal element tube by passing it between a die for forming the outer surface and a plug for forming the inner surface,
A discharge port is provided only in an upper half region of the outer peripheral surface on the rear side of the bearing portion in the plug, and the discharge port communicates with the hollow portion of a hollow rod that supports the plug. Metal tube drawing device to do.

  In the invention of [1], when the lubricating oil is attached to the inner surface of the raw pipe before passing through the bearing portion of the plug, the lubricating oil is attached to at least a part of the upper half area of the inner surface of the raw pipe. The lower half of the inner surface of the pipe is selectively attached without causing the lubricant to adhere, and part of the lubricant attached to the upper half of the inner face of the inner pipe before passing through the bearing portion of the plug is After the attachment, the upper part of the inner surface of the inner surface of the pipe before passing through the bearing part of the plug is retained and attached to the lower part of the inner surface of the inner part of the pipe by its own weight until the raw pipe moves to the bearing part of the plug. Lubricant is attached to the pipe (supplied as needed), so it is possible to prevent depletion of the lubricating oil in the upper half area of the inner surface of the raw pipe during the drawing process (the state of running out of the lubricating oil) and to prevent seizure during drawing. be able to. That is, according to this drawing method, a drawing tube without seizure can be manufactured.

  The “selective adhesion” defines the relationship of the amount of adhesion when lubricating oil is adhered to the inner surface of the raw tube before passing through the bearing portion of the plug. It is assumed that the amount of movement to another region (lower half region) due to its own weight over time after adhering to the surface is not considered (the amount of movement of the lubricant after adhering is ignored).

  In the invention of [2], a discharge port is provided in the lower half region of the hollow rod supporting the plug, a nozzle protruding from the outer peripheral surface of the rod is provided in the discharge port, and the tip of the nozzle is substantially upward. Since the lubricating oil is discharged from the opening at the end of the plug, when the lubricating oil is attached to the inner surface of the raw tube before passing through the bearing portion of the plug, at least a part of the upper half region on the inner surface of the raw tube It is possible to sufficiently adhere the lubricant to the surface and sufficiently prevent the lubricant from being exhausted (run out of lubricant) in the upper half area of the inner surface of the pipe during the drawing process. can do.

  In the invention of [3], since the distance between the tip opening of the nozzle and the bearing portion of the plug in the pulling direction is 20 cm or less, the lubricating oil application position (to the upper half area of the inner surface of the raw pipe) is connected to the plug. Since the distance to the bearing portion is short and the exhaustion (lubricating oil) of the lubricating oil in the upper half region of the inner surface of the raw pipe during drawing can be sufficiently prevented, seizure during drawing can be sufficiently prevented.

  In the invention of [4], the upper half region on the inner surface of the raw tube from when the plug and the hollow rod are inserted into the raw tube until it is inserted through the die and set. Since the lubricant is attached to at least a part of the tube and the selective adhesion is performed so that the lubricant does not adhere to the lower half region of the inner surface of the tube, the resistance when inserting the plug and the rod into the tube is reduced. An effect can be obtained and seizure during drawing can be prevented.

  In the invention of [5], during the inserting operation of inserting the plug and the hollow rod into the inside of the raw tube, the lubricating oil is supplied into the plug and the lubricating oil is discharged from the discharge port provided at the tip of the plug. Accordingly, the lubricating oil is attached to at least a part of the upper half area of the inner surface of the raw pipe, and the selective attachment is performed so that the lubricating oil is not attached to the lower half area of the inner face of the raw pipe. Occasionally, the lubricating oil can be sufficiently adhered from the starting position of drawing (tip position) to the entire circumference of the inner surface of the raw tube, and seizure of the drawing start position (tip part) can be sufficiently prevented.

  In the invention of [6] (drawing apparatus), a discharge port is provided in the lower half region of the plug, a nozzle protruding from the outer peripheral surface of the rod is provided in the discharge port, and the tip of the nozzle is opened substantially upward. Therefore, by discharging the lubricating oil from the opening at the tip, the lubricating oil can be sufficiently adhered to at least a part of the upper half area on the inner surface of the raw tube before passing through the plug, and The seizure at the time can be prevented.

  In the invention of [7] (drawing apparatus), the discharge port is provided only in the upper half region of the outer peripheral surface on the rear side of the bearing portion in the plug, and the discharge port is the hollow portion of the hollow rod that supports the plug. Therefore, by discharging the lubricating oil from this discharge port, the lubricating oil can be sufficiently adhered to at least a part of the upper half area of the inner surface of the raw pipe before passing through the plug, and the drawing is performed. It is possible to prevent seizure during the process.

It is a longitudinal cross-sectional view which shows one Embodiment of the drawing apparatus for enforcing the drawing method of this invention. FIG. 2 is a cross-sectional view of a rod and a raw tube in the apparatus of FIG. 1. It is a longitudinal cross-sectional view which shows other embodiment of the drawing apparatus for enforcing the drawing method of this invention. It is sectional drawing of the XX line in FIG. It is sectional drawing of the rod and the raw tube in the drawing-out apparatus which concerns on other embodiment. It is sectional drawing which shows other embodiment of the drawing apparatus. It is sectional drawing which shows the state which is discharging the lubricating oil from the discharge port of a rod in the insertion operation | work which inserts a plug and a rod in the inside of a raw tube. It is sectional drawing which shows the state which is discharging the lubricating oil from the front-end | tip opening part of a plug in the insertion operation | work which inserts a plug and a rod in the inside of a raw tube. FIG. 4 is a cross-sectional view of a rod and a raw tube in the drawing device used in Comparative Example 1. 6 is a cross-sectional view of a rod and a raw tube in a drawing device used in Comparative Example 2. FIG.

  FIG. 1 is a longitudinal sectional view showing an example of a drawing apparatus 1 for carrying out the metal pipe drawing method of the present invention. The drawing device 1 includes a drawing tool and a lubricating oil supply unit that supplies lubricating oil to the outer surface and the inner surface of the metal base tube 2. The drawing method and drawing apparatus 1 according to the present invention draws a metal base tube 2 by drawing it in the horizontal direction.

  The drawing tool includes a drawing die 10 and a plug 11. The die 10 includes a die main body 13 fitted in a die case 12, and the die main body 13 includes an approach portion 14 on the inner peripheral surface of a central die hole and a bearing portion 15 continuing to the front side thereof. Have.

  The plug 11 is attached to and supported by the tip of a rod 20 made of a hollow tube. The plug 11 has an approach portion 16 on the outer peripheral surface and a bearing portion 17 continuing to the front side thereof.

  By pulling the metal base tube 2 between the die 10 and the plug 11 in the horizontal direction, the outer surface of the tube is formed by the bearing portion 15 of the die body 13 and the inner surface of the tube is the bearing portion of the plug 11. 17 and the drawn tube 3 is manufactured.

  A supply pipe 18 is arranged at the upper position behind the die 10 as the outer surface lubricating oil supply section with the front end facing downward. Lubricating oil L supplied from a tank (not shown) is discharged toward the raw pipe 2 from the tip of the supply pipe 18, and the lubricating oil L adhering to the upper part of the outer surface of the raw pipe 2 travels along the outer surface to the outer surface of the raw pipe 2. The excess lubricating oil L flows down. Then, with the lubricating oil L adhering to the outer surface of the raw pipe 2, the raw pipe 2 is passed between the die 10 and the plug 11 to perform drawing processing.

  A pair of discharge ports 21 is provided in the lower half region of the hollow rod 20 that supports the plug 11 (see FIG. 2) as the inner surface lubricating oil supply section, and each discharge port 21 protrudes from the outer peripheral surface of the rod 20. The nozzles 31 are connected to each other, and the tip end of the nozzle 31 is opened substantially upward to form a tip opening portion 32. The nozzle 31 connected to the discharge port 21 is extended obliquely downward from the outer peripheral surface of the rod 20 and then bent (may be curved) and further extended substantially upward. A tip opening 32 is provided at the tip of the lever so as to open substantially upward (see FIG. 2). The hollow portion (hollow inner space) of the rod 20 is used as a supply path for the lubricating oil L (see FIG. 1). In the present embodiment, as shown in FIG. 2, one discharge port 21 is provided obliquely to the left in the lower half region of the rod 20, and the other discharge port 21 is disposed obliquely to the right in the lower half region of the rod 20. The nozzle 31 is connected and fixed to each discharge port 21. Lubricating oil L supplied from behind to a hollow portion of the rod 20 from a tank (not shown) is discharged from the tip opening portion 32 of the nozzle 31 through the discharge port 21, and at least in the upper half region of the inner surface of the base tube 2. It adheres to a part and then spreads along the inner surface of the raw tube 2 in the circumferential direction.

  Thus, the drawing tube 3 is manufactured by supplying the lubricating oil L to the outer surface and the inner surface of the tube 2 and pulling the tube 2 in the horizontal direction.

  Thus, when the lubricating oil L is attached to the inner surface of the base tube 2 before passing through the bearing portion 17 of the plug 11, the lubricating oil L is discharged upward from the tip opening portion 32 of the nozzle 31, thereby Lubricating oil L is attached to at least a part of the upper half region (the region above the one-dot chain line H in the inner surface of the raw tube in FIG. 2) and the lower half region (in the figure) on the inner surface of the raw tube 2 2, selective adhesion is performed so that the lubricating oil does not adhere to the inner surface of the base pipe below the one-dot chain line H).

  By performing the selective attachment to the inner surface of the raw tube 2 before passing through the bearing portion 17 of the plug 11, a part of the lubricating oil L attached to the upper half region of the inner surface of the raw tube 2 is attached after the attachment. Moves to the lower region of the inner surface of the raw tube 2 due to its own weight, and stays and adheres to the upper half region of the inner surface of the raw tube 2 before passing through the bearing portion of the plug 11. (Supplied as needed), so that it is possible to prevent the lubricating oil from being depleted in the upper half area of the inner surface of the pipe during the drawing process (ie, the state of running out of the lubricating oil). In this state, the drawing process can be performed (the drawing process is performed between the bearing part 15 of the die 10 and the bearing part 17 of the plug 11), and seizure during the drawing process can be prevented.

When a plurality of raw pipes 2 are sequentially drawn in the drawing device 1, the drawing process and the supply of lubricating oil to the inner face of the raw pipe are performed by repeating the following (i) to (vi).
(I) Supplying the lubricating oil L into the rod 20 and discharging it from the tip opening portion 32 of the nozzle 31, so that the lubricating oil L is supplied to the inner surface of the raw tube 2, and (ii) the raw tube 2 After the drawing is completed, the supply of the lubricating oil L is stopped. (Iii) The drawing pipe 3 is taken out from the drawing apparatus 1, and the next raw pipe is set in the drawing apparatus 1. (iv) The supply of the lubricating oil L is restarted. (V) Supply until the discharge amount of the lubricating oil L is stabilized (vi) Return to (i).

  In the present embodiment, as shown in FIG. 2, since the tip opening 32 of the nozzle 31 is located at a position lower than the horizontal line H passing through the center of the raw tube 2, the discharge distance to the upper half area of the inner surface of the raw tube 2 In addition, the diffusion region can be increased, whereby the lubricating oil can be adhered over a wider range in the upper half region of the inner surface of the raw tube 2, so that seizure at the time of drawing can be more effectively prevented.

  Of course, as shown in FIG. 5, the drawing may be performed by adopting a configuration in which the tip opening 32 of the nozzle 31 is positioned higher than a horizontal line H passing through the center of the raw tube 2. However, it is preferable to perform the drawing process by adopting a configuration in which the tip opening portion 32 of the nozzle 31 is located at a position lower than the horizontal line H passing through the center of the raw tube 2 in that seizure at the time of drawing can be more sufficiently prevented. .

  Moreover, in the said embodiment, although one discharge port 21 and the other discharge port 21 are provided in the same position in the extraction direction among a pair of discharge ports (refer FIG. 1, 2), especially such a structure. For example, as shown in FIGS. 3 and 4, one discharge port 21 and the other discharge port 21 may be provided at different positions in the drawing direction. That is, in the drawing device 1 shown in FIGS. 3 and 4, the position in the drawing direction of the tip opening 32 of the nozzle 31 connected to one discharge port provided diagonally to the left in the lower half region of the rod 20; The position in the drawing direction of the tip opening 32 of the nozzle 31 connected to the other discharge port provided obliquely downward to the right in the lower half region of the rod 20 is different.

  Further, when performing the above selective attachment, that is, when performing the above selective attachment to the inner surface of the raw tube 2 before passing through the bearing portion 17 of the plug 11, the drawing device 1 having the configuration shown in FIG. 6 is used. Also good.

  In the drawing device 1 having the configuration shown in FIG. 6, the first flow path 24 communicating with the hollow portion of the rod 20 is formed in the plug 11 along the axial direction thereof, and the outer periphery of the plug 11 on the rear side from the bearing portion 17. A discharge port 23 is provided at the apex of the surface, and the discharge port 23 communicates with the first flow path 24 via a second flow path 25 extending substantially in the vertical direction. In the drawing device 1, no discharge port is formed in the rod 20. Thus, when the lubricating oil L is attached to the inner surface of the base tube 2 before passing through the bearing portion 17 of the plug 11, by discharging the lubricating oil L upward from the discharge port 23 at the apex of the plug 11, Selective adhesion (selective adhesion in which the lubricating oil L is adhered to at least a part of the upper half area on the inner surface of the element tube 2 and the lubricating oil is not adhered to the lower half area on the inner surface of the element tube 2) To do. As a result, as in the above-described embodiment, it is possible to prevent the lubricating oil from being depleted (lubricated oil state) in the upper half area of the inner surface of the pipe during drawing, that is, the lubricating oil L over the entire circumference of the inner surface of the pipe 2. Can be drawn out (attached between the bearing portion 15 of the die 10 and the bearing portion 17 of the plug 11), and seizure during drawing can be prevented. .

  In the drawing apparatus 1 (FIGS. 1 to 5), the distance between the tip opening 32 of the nozzle 31 and the bearing portion 17 of the plug 11 in the drawing direction is preferably set to 20 cm or less. Moreover, in the drawing apparatus 1 of FIG. 6, it is preferable that the distance between the discharge port 23 of the plug 11 and the bearing portion 17 of the plug 11 in the drawing direction is set to 20 cm or less. Since the distance from the application position of the lubricating oil L (to the upper half area of the inner surface of the raw tube) to the bearing portion 17 of the plug 11 is short by setting in such a range, the inside of the raw tube during the drawing process Lubricating oil depletion (out of lubricating oil) in the upper half area of the surface can be sufficiently prevented, and seizure during drawing can be sufficiently prevented.

  When the selective attachment is performed on the inner surface of the raw tube 2 before passing through the bearing portion 17 of the plug 11, the selective attachment timing is as shown in the above embodiment (FIGS. 1 to 6). 2 may be after the die 10 is inserted and set, or before the blank tube 2 is inserted and set in the die 10.

  The following example can be given as an example of performing the above selective attachment before inserting the raw tube 2 into the die 10. First, in the example shown in FIG. 7, during the insertion operation of inserting the plug 11 and the hollow rod 20 into the raw tube 2, the lubricating oil L is discharged from the discharge port 21 provided at the top of the rod 20. In the stage before the tube 2 is inserted into the die 10, the selective adhesion (the lubricating oil L is adhered to at least a part of the upper half region of the inner surface of the tube 2 and the inner surface of the tube 2 is set) In this case, selective adhesion without lubricating oil is performed in the lower half of the area.

  Further, in FIG. 8, a discharge port 22 communicating with the hollow portion of the rod 20 is formed at the tip of the plug 11, and a nozzle 33 protruding forward from the tip of the plug is provided at the discharge port 22. The front end of the head is opened substantially upward, and a front end opening 34 is formed. In the example shown in FIG. 8, during the insertion operation of inserting the plug 11 and the hollow rod 20 into the raw tube 2, the lubricating oil L is supplied into the plug 11 through the hollow portion of the rod 20 and the plug 11 is inserted. In the stage before the base tube 2 is inserted and set into the die 10 by discharging the lubricating oil L substantially upward from the tip opening 34 of the nozzle 33 attached to the tip of the eleventh tip, the selective attachment ( The lubricating oil L is attached to at least a part of the upper half region on the inner surface of the raw tube 2 and the selective attachment is performed so that the lubricating oil is not attached to the lower half region on the inner surface of the raw tube 2. .

  In the present invention, the length of the pipe 2 to be drawn is not limited. However, for short pipes, the lubrication of the inner surface can be achieved by applying lubricating oil to the plug before drawing as in the prior art. Therefore, when a long element tube is pulled out, a remarkable effect is obtained, and it is suitable for pulling out a long element tube. Specifically, a remarkable effect can be obtained for a raw tube of 2 m or more, particularly 2.5 m or more.

  In this invention, the raw material (metal seed | species) of the metal raw pipe 2 of drawing object is not specifically limited, For example, aluminum, iron, copper, or these alloys etc. are mentioned. The present invention is suitable for the production of an aluminum tube for a photosensitive drum substrate because a remarkable effect is obtained when a long elementary tube is drawn.

  Next, specific examples of the present invention will be described, but the present invention is not particularly limited to these examples.

<Example 1>
The metal blank 2 was drawn using the drawing device 1 having the configuration shown in FIGS. Aluminum alloy (Mn: 1.12% by mass, Si: 0.11% by mass, Fe: 0.39% by mass, Cu: 0.16% by mass, Zn: 0.01% by mass, Mg: 0.02% by mass) And the remaining aluminum and unavoidable impurities) are extruded under the conditions of an extrusion temperature of 520 ° C. and an extrusion speed of 5 m / min to obtain a cylindrical tube having an outer diameter of 32 mm and a wall thickness of 1.5 mm. The cut one was used as the metal base tube 2.

  In the drawing device 1, the approach angle of the approach portion 14 of the die 10 is 15 °, the bearing length of the bearing portion 15 of the die 10 is 15 mm, and the approach angle of the approach portion 16 of the plug 11 is 7 °. The bearing length of the bearing portion 17 of the plug 11 is 2 mm.

  When the lubricating oil L is discharged from the tip of the supply pipe 18 of the drawing device 1 toward the outer surface of the raw tube 2, the lubricating oil L adhering to the upper portion of the outer surface of the raw tube 2 travels along the outer surface to the outer surface of the raw tube 2. It is supplied to the entire circumference and excess lubricating oil L flows down.

  In addition, when the lubricating oil L was attached to the inner surface of the base tube 2, the lubricating oil L was selectively attached. That is, when the lubricating oil L is adhered to the inner surface of the raw tube 2 before passing through the bearing portion 17 of the plug 11, the lubricating oil L is discharged upward from the tip opening portion 32 of the nozzle 31, thereby The lubricating oil L was adhered to at least a part of the upper half area on the inner surface of the inner surface 2 and selective adhesion was performed so that the lubricating oil was not adhered to the lower half area on the inner surface of the base tube 2. A part of the lubricating oil L attached to the upper half region of the inner surface of the raw tube 2 moves to the lower region of the inner surface of the raw tube 2 due to its own weight after adhering, but the bearing portion of the plug 11 The drawing process was performed so that the lubricating oil was continuously adhered (supplied as needed) to the upper half area of the inner surface of the raw tube 2 before passing.

While supplying the lubricating oil L to the outer surface and the inner surface of the raw tube 2 in the manner as described above, the drawing tube is drawn at a drawing speed of 30 m / min, an outer diameter reduction rate of 16%, and a cross-sectional area reduction rate of 32%. 3 was obtained. As the outer surface and inner surface lubricating oil L, “Strol ES150” (viscosity: 1.4 × 10 ⁻⁴ m ² / s) manufactured by Kyoei Oil Chemical Co., Ltd. was used.

  The obtained drawing tube 3 was transferred from the drawing device 1 to a conveyor, allowed to cool to room temperature, and cut to a length of 260 mm.

<Example 2>
1 and 2, a configuration in which only one nozzle 31 of the pair (two) nozzles is provided (only the left discharge port 21 and the left nozzle 31 in FIG. 2 are provided). A drawing tube 3 having a length of 260 mm was obtained in the same manner as in Example 1 except that the drawing device was used except that the right-side discharge port and the right-side nozzle were not provided.

<Example 3>
Example 1 except that the drawing device 1 having the configuration shown in FIGS. 3 and 4 (a configuration in which two nozzles 31 are provided but the positions in the drawing direction are different from each other) is used as the drawing device. Similarly, a drawn tube 3 having a length of 260 mm was obtained.

<Comparative Example 1>
As the drawing device, the same as in Example 1 except that a drawing device having a configuration in which a discharge port 51 and a nozzle 52 connected to the discharge port 51 are provided at the bottom of the rod 20 as shown in FIG. 9 is used. Thus, a drawn tube 3 having a length of 260 mm was obtained.

<Comparative example 2>
Example 1 except that a drawing device having a configuration in which a discharge port 53 and a nozzle 54 connected to the discharge port 53 are provided obliquely below the rod 20 as shown in FIG. Similarly, a drawn tube 3 having a length of 260 mm was obtained.

Whether or not seizure occurred in the drawn tube 3 obtained as described above was examined, and the anti-seizure property was evaluated based on the following criteria. These evaluation results are shown in Table 1.
(Criteria)
“○”: no seizure occurred “×”: seizure occurred in the upper half area of the inner surface of the drawn pipe “XX”: seizure occurred in the upper half area of the inner surface of the drawn pipe Seizure also occurred on a part of the upper side of the lower half area of the inner surface.

  As is apparent from the table, according to the drawing method of the present invention, it is possible to produce a drawn tube that is not seized.

  The method for drawing a metal tube according to the present invention is suitable for mass production of an aluminum tube for a photosensitive drum substrate because it can reliably attach a lubricating oil to the inner surface of the tube in continuous drawing of a plurality of metal tube. ing.

DESCRIPTION OF SYMBOLS 1 ... Drawing apparatus 2 ... Metal base pipe 3 ... Drawing pipe 10 ... Die 11 ... Plug 20 ... Rod 21 ... Discharge port (Discharge port of rod)
23 ... Discharge port (plug discharge port)
31 ... Nozzle 32 ... Tip opening H ... Horizontal plane L passing through center of raw tube ... Lubricating oil

Claims (5)

In the drawing method of a metal tube, the metal tube is drawn by passing it between a die for forming the outer surface and a plug for forming the inner surface.
When attaching lubricating oil to the inner surface of the raw tube before passing through the bearing portion of the plug,
A discharge port is provided in a lower half region of the hollow rod supporting the plug, a nozzle protruding from the outer peripheral surface of the rod is provided in the discharge port, a tip of the nozzle is opened substantially upward, By supplying the lubricating oil into the rod and discharging the lubricating oil from the tip opening of the nozzle , the lubricating oil is attached to at least a part of the upper half region of the inner surface of the raw tube and the inner surface of the raw tube A method for pulling out a metal tube, wherein selective adhesion is performed so that lubricating oil does not adhere to the lower half of the region. The method of drawing a metal tube according to claim 1 , wherein the distance between the tip opening of the nozzle and the bearing portion of the plug in the drawing direction is 20 cm or less. At least a part of the upper half area on the inner surface of the raw tube from when the plug and the hollow rod are inserted into the raw tube until the raw tube is inserted through the die and set. 3. The method of pulling out a metal tube according to claim 1 or 2 , wherein the lubricating oil is adhered to the inner surface of the base tube and selective adhesion is performed so that the lubricating oil is not adhered to the lower half region of the inner surface of the base tube. In the drawing method of a metal tube, the metal tube is drawn by passing it between a die for forming the outer surface and a plug for forming the inner surface.
When attaching lubricating oil to the inner surface of the raw tube before passing through the bearing portion of the plug,
During the insertion operation of inserting the plug and the hollow rod into the inner tube, the lubricating oil is supplied into the plug and is discharged from a discharge port provided at the tip of the plug, thereby Lubricating oil adheres to at least a part of the upper half area on the inner surface of the raw pipe and lubricates the lower half area on the inner surface of the raw pipe until the raw pipe is inserted through the die and set. A method of drawing a metal tube, wherein selective adhesion without oil is performed. In a drawing apparatus for drawing a metal element tube by passing it between a die for forming the outer surface and a plug for forming the inner surface,
A discharge port is provided in a lower half region of the hollow rod that supports the plug, a nozzle that protrudes from the outer peripheral surface of the rod is provided in the discharge port, and a tip of the nozzle opens substantially upward. A metal tube drawing apparatus characterized by that.

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