JP2006272392A - Rifle tube drawing tool, and rifle tube manufacturing method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rifle tube drawing tool capable of preventing occurrence of seizure during a drawing and being easily and inexpensively be manufactured. <P>SOLUTION: In the rifle tube drawing tool 1, a plurality of spiral grooves 1a are formed on its outer circumferential surface. The first line L1 passing through a top except a tip of the tool of one groove ridge 1b across the axis of the tool in side view is inclined inwardly from a tip side of the tool toward a rear end side. The angle θ1 formed by the first line with respect to the axial direction of the tool in plan view is set to be larger than the angle θ2 formed by the second line L2 passing through a bottom part except the tip of the tool of one spiral groove across the axis of the tool in side view. An edge of one groove ridge is chamfered in an outwardly projecting curve, and its radius r of curvature is set to be a constant value from the tip of the tool to its rear end. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a tool for use in manufacturing a rifle tube by drawing a base tube and a method for manufacturing a rifle tube using the same, and in particular, it can prevent occurrence of seizure during drawing and is easy and inexpensive. The present invention relates to a rifle tube drawing tool that can be manufactured and a rifle tube manufacturing method using the tool.

  Conventionally, in various heat exchangers, so-called rifle tubes in which a plurality of spiral ribs are formed on the inner peripheral surface are preferably used in order to disturb the flow of fluid and increase heat transfer efficiency. Such a rifle tube is obtained by drawing a rifle tube drawing tool (plug) having a plurality of spiral grooves formed on the outer peripheral surface thereof while drawing the raw tube while squeezing the raw tube with a die. Manufactured.

Here, since the blank pipe to be drawn is accompanied by severe plastic deformation, seizure is likely to occur between the drawing tool. For this reason, conventionally, various proposals for preventing the occurrence of seizure between the blank tube and the drawing tool have been made. For example, in Patent Document 1, the radius of curvature of the portion where the opposite side walls and the bottom surface forming the spiral groove of the plug intersect is kept constant from the front end side to the rear end side of the plug (the curvature radius is 0). And a rifle tube drawing plug characterized in that the diameter of the plug is reduced with a constant gradient from the tip end side to the rear end side of the plug. Yes.
JP 2001-179327 A

  The plug described in Patent Document 1 has a constant radius of curvature at the bottom edge of the spiral groove (a portion where the opposite side walls and the bottom surface that form the spiral groove intersect), and therefore, a plurality of plugs according to various curvature radii. There is no need to prepare a grindstone, and there is an advantage that it can be manufactured relatively easily and inexpensively.

  However, the plug described in Patent Document 1 has a problem that a sufficient burn-in prevention effect cannot be obtained. More specifically, at least in the initial stage of the drawing process, the bottom of the spiral groove formed in the plug of Patent Document 1 is not sufficiently filled with the raw material, so the bottom edge is formed in a curved shape. Even so, there is a problem that the bottom edge does not contribute to the prevention of burn-in and a sufficient burn-in prevention effect cannot be obtained.

  The present invention has been made to solve such a problem of the prior art, and can prevent the occurrence of seizure at the time of drawing and can easily and inexpensively manufacture a rifle tube drawing tool. It aims at providing the manufacturing method of the used rifle tube.

  In order to solve the above problems, the inventors of the present invention have intensively studied. As a result, unlike the bottom of the spiral groove, the top of the spiral groove of the drawing tool is pushed into the blank tube at the initial stage of drawing. Therefore, it has been found that it is always in contact with the surface of the raw tube and is a main cause of seizure between the tool and the raw tube. Then, the edge of the groove of the spiral groove is chamfered in a curved line or a straight line to reduce the contact area between the top of the groove and the raw pipe, and thereby the friction generated between the top of the groove and the raw pipe It was conceived that if the resistance is reduced, the occurrence of seizure can be effectively prevented. Furthermore, when chamfering the edge of the groove of the spiral groove in a curved shape, it spirals from the rear end side of the tool (the side where the element tube is inserted into the die) to the tip end side (the side where the element tube is pulled out of the die). As long as the depth of the groove is increased stepwise (the height of the groove height is increased), the plastic deformation of the blank tube during the drawing process can be slowed down, and the radius of curvature of the chamfered portion can be reduced to the tip of the tool. It has been found that the occurrence of seizure can be effectively prevented without increasing in steps from the side to the rear end side (even with a constant radius of curvature).

  The present invention has been completed based on the findings of the inventors. That is, the present invention is a rifle tube drawing tool that is inserted into the inner surface of an element tube that is drawn while being squeezed by a die and has a plurality of spiral grooves formed on the outer peripheral surface thereof, and is a tool for drawing the rifle tube in a side view. A first straight line that passes through the top of the groove that intersects the axis of the tool excluding the tip of the tool is inclined inward from the tip end side to the rear end side of the tool, and the side surface The first straight line passing through the bottom of the one spiral groove that intersects the axis of the tool in view, excluding the tip of the tool, is more than the angle formed with respect to the axial direction of the tool in plan view. The angle formed by the straight line with respect to the axial direction of the tool in plan view is set to be larger, and the edge of the one groove is chamfered in an outwardly convex curved shape, and the radius of curvature of the tool is A constant value from the front end to the rear end That it is set there is provided a rifle tube drawing processing tool according to claim.

  According to such an invention, the first straight line passing through the top portion excluding the tip portion of the tool of one groove mountain intersecting the axis of the tool in a side view is inward from the tip portion side to the rear end portion side of the tool. Than the angle formed by the second straight line passing through the bottom of the spiral groove excluding the tip of the tool in the side view and intersecting the axis of the tool with respect to the axis direction of the tool in plan view. The angle formed by the first straight line with respect to the axial direction of the tool in plan view is set larger. In other words, the depth of the spiral groove is set so as to increase stepwise from the rear end side to the front end side of the tool (the height of the groove crest is increased). It is possible to slow the plastic deformation of the tube. In addition, since the edge of the groove is chamfered in a curved shape that protrudes outward, the contact area between the top of the groove and the raw tube is reduced, and this occurs between the top of the groove and the raw tube. The frictional resistance will be reduced. With the above configuration, the occurrence of seizure between the tool and the raw tube can be effectively prevented. Furthermore, since the radius of curvature of the chamfered portion is set to a constant value from the tip end portion to the rear end portion of the tool, there is no need to prepare a plurality of grindstones according to various curvature radii when producing the tool, It has the advantage that it can be manufactured easily and inexpensively.

  In the present invention, the “front end” of the tool means the end on the side where the raw tube is pulled out from the die, and the “rear end” means the end on the side where the raw tube is inserted into the die. In addition, the “groove peak top” means a groove peak portion that is farthest from the axis in a cross section orthogonal to the tool axis, and the “first straight line passing through the groove peak” means the tool axis. This means a straight line that passes through the top of each groove in each cross section when considering a plurality of cross sections orthogonal to each other, and is the minimum based on the coordinate data of each top as well as the straight line that connects each top of the groove in each cross section. It is a concept including a straight line approximated by square approximation or the like. Further, “the bottom of the spiral groove” means a portion of the spiral groove closest to the axis in the cross section orthogonal to the axis of the tool, and “the second straight line passing through the bottom of the spiral groove” means the axis of the tool Means a straight line that passes through the bottom of the spiral groove in each cross-section when considering a plurality of cross-sections orthogonal to each other, and is the minimum based on the coordinate data of each bottom as well as the straight line connecting the bottoms of the spiral groove in each cross-section It is a concept including a straight line approximated by square approximation or the like. Furthermore, “the angle formed with respect to the axial direction of the tool in plan view” means the angle formed with respect to the axial direction when the first straight line (or the second straight line) is viewed from a direction orthogonal to the side view. means.

  Further, in order to solve the above-mentioned problems, the present invention is a rifle tube drawing tool which is inserted into the inner surface of an element pipe to be drawn while being drawn by a die and has a plurality of spiral grooves formed on the outer peripheral surface thereof. A first straight line passing through the top of the groove that intersects the axis of the tool in a side view, excluding the tip of the tool, is inward from the tip of the tool toward the rear end. An angle formed by a second straight line passing through the bottom of the spiral groove except for the tip of the tool with respect to the axis of the tool in a plan view, which is inclined in a side view and intersects the axis of the tool in a side view Rather, the angle formed by the first straight line with respect to the axial direction of the tool in plan view is set to be larger, and the edge of the one groove is linearly chamfered. For rifle tube drawing It is also provided as a tool.

  Also according to such an invention, since the depth of the spiral groove is set to increase stepwise from the rear end side to the front end side of the tool, the plastic deformation of the raw tube during the drawing process is slowed down. Is possible. In addition, since the edge of the groove is chamfered in a straight line, the contact area between the top of the groove and the base pipe is reduced, thereby reducing the frictional resistance generated between the top of the groove and the base pipe. It will be. With the above configuration, the occurrence of seizure between the tool and the raw tube can be effectively prevented. Furthermore, since the chamfered portion only needs to be chamfered in a straight line, there is no need to prepare a plurality of grindstones when manufacturing the tool, and there is an advantage that it can be easily and inexpensively manufactured.

  Furthermore, in order to solve the above-mentioned problems, the present invention is a rifle tube drawing tool that is inserted into the inner surface of an element pipe that is drawn while being squeezed by a die and has a plurality of spiral grooves formed on the outer peripheral surface thereof. In addition, it is also provided as a rifle tube drawing tool characterized in that the edge of one groove crest that intersects the axis of the tool in a side view is chamfered linearly.

  Also according to such an invention, since the edge of the groove is linearly chamfered, the contact area between the top of the groove and the raw pipe is reduced, and this causes friction generated between the top of the groove and the raw pipe. The resistance is reduced, and as a result, the occurrence of seizure between the tool and the raw tube can be effectively prevented. Further, since the chamfered portion only needs to be chamfered in a straight line, there is no need to prepare a plurality of grindstones when manufacturing the tool, and there is an advantage that it can be easily and inexpensively manufactured.

  The present invention includes a method for producing a rifle tube, comprising a step of drawing while drawing the raw pipe with a die in a state where any of the rifle tube drawing tools is inserted into the inner face of the raw pipe. Also provided as

  The rifle tube drawing tool according to the present invention has the advantage that it can prevent seizure during drawing and can be easily and inexpensively manufactured.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a side view schematically showing a state in which a blank pipe is drawn using a rifle tube drawing tool (hereinafter, appropriately abbreviated as “tool”) according to an embodiment of the present invention. is there. FIG. 2 is a schematic diagram showing a partially enlarged cross-sectional shape perpendicular to the tool axis, with respect to one groove crest and one spiral groove intersecting with the tool axis shown in FIG. 1 is a cross-sectional view taken along arrow AA in FIG. 1, (b) is a cross-sectional view taken along arrow BB in FIG. 1, and (c) is a cross-sectional view taken along arrow CC in FIG. FIG. 3 is a plan view of a first straight line passing through each top of the groove crest in each cross section shown in FIG. 2 and a second straight line passing through each bottom of the spiral groove (viewed from above in FIG. 1). Figure). As shown in FIG. 1, when drawing the blank tube 3 using the tool 1 according to the present embodiment, the tool 1 is concentrically arranged with respect to the die 2 and the blank tube 3 in the same manner as in the past. The raw tube 3 is inserted into the inner surface of the tube 3 and pulled out in the direction of the arrow in FIG. At this time, the raw tube 3 is squeezed (reduced in diameter) by the die 2 and the inner surface of the raw tube 3 is constrained by the tool 1, so that the spiral is formed on the outer peripheral surface of the tool 1. It will bite into the groove 1a. Thereby, the spiral rib 3a is formed in the inner peripheral surface of the base tube 3 after drawing.

  Here, as shown in FIG. 3, the tool 1 according to the present embodiment excludes the tip of the tool 1 of one groove crest 1b that intersects the axis of the tool 1 in a side view (the inner diameter of the raw tube 3 is reduced). The first straight line L1 passing through the apex portions 1ba, 1bb, 1bc (see also FIG. 2) excluding a specified range (for example, a range of about 10 to 15 mm from the front end) is from the front end side to the rear end side of the tool 1 1a, 1ab, 1ac (excluding the tip of the tool 1 of the spiral groove 1a that is inclined inwardly (in a direction approaching the axis) and intersects the axis of the tool 1 in a side view) 2), the first straight line L1 is more in the axial direction of the tool 1 than the angle θ2 (θ2 = 0 ° in the example shown in FIG. 3) formed by the second straight line L2 with respect to the axial direction of the tool 1. The feature is that the angle θ1 formed with respect to the angle is set larger. Further, as shown in FIG. 2, the edge of the groove 1b is chamfered in an outwardly convex curved shape, and the radius of curvature r is set to a constant value from the front end portion to the rear end portion of the tool 1. It is characterized by being. The angles θ1 and θ2 are preferably set to values in the range of 0 to 5 °.

  Since the tool 1 according to the present embodiment has the configuration described above, the depth of the spiral groove 1a gradually increases from the rear end side to the front end side of the tool 1 (the height of the groove 1b). Is high). Therefore, it is possible to slow the plastic deformation of the raw tube 3 during the drawing process. Further, since the edge of the groove 1b is chamfered in an outwardly convex curved shape, the contact area between the top of the groove 1b and the element tube 3 is reduced, thereby the top of the groove 1b and the element tube 3 are reduced. The frictional resistance generated between the two is reduced. With the above configuration, the occurrence of seizure between the tool 1 and the raw tube 3 can be effectively prevented. Further, since the curvature radius r of the chamfered portion is set to a constant value from the front end portion to the rear end portion of the tool 1, a plurality of grindstones corresponding to various curvature radii are prepared when the tool 1 is manufactured. It is not necessary and can be manufactured easily and inexpensively.

  In addition, as a tool which concerns on this invention, it is not restricted to what has the cross-sectional shape shown in FIG. 2, It is also possible to employ | adopt the tool 1A which has a cross-sectional shape as shown in FIG. FIG. 4 is a schematic diagram showing a partially enlarged cross-sectional shape perpendicular to the axis of the tool with respect to one groove crest and one spiral groove intersecting with the axis of the tool 1A. FIG. 5B is a cross-sectional view of the front end side, FIG. 5B is a cross-sectional view of an intermediate portion in the axial direction of the tool 1A, and FIG. FIG. 5 is a plan view of a first straight line passing through each top of the groove mountain in each cross section shown in FIG. 4 and a second straight line passing through each bottom of the spiral groove (viewed from above in FIG. 1). Figure). As shown in FIG. 4 or 5, the tool 1 </ b> A according to this embodiment is similar to the tool 1 shown in FIG. 2 or 3, and the tool 1 having one groove 1 b that intersects the axis of the tool 1 in a side view. The first straight line L1 passing through the top portions 1ba, 1bb, and 1bc excluding the tip portion of the tool is inclined inward (in a direction approaching the axis) from the tip portion side to the rear end portion side of the tool 1A, and the side surface The angle θ2 formed by the second straight line L2 passing through the bottom portions 1aa, 1ab, and 1ac excluding the tip portion of the tool 1 in one spiral groove 1a that intersects the axis of the tool 1A with respect to the axial direction of the tool 1A (see FIG. In the example shown in FIG. 5, the angle θ1 formed by the first straight line L1 with respect to the axial direction of the tool 1A is set to be larger than θ2 = 0 °. Moreover, unlike the tool 1 shown in FIG. 2, the edge of the groove 1b is chamfered linearly. The angles θ1 and θ2 are preferably set to values in the range of 0 to 5 °.

  The tool 1A according to the present embodiment is also set so that the depth of the spiral groove 1a is gradually increased from the rear end side to the front end side of the tool 1A (the height of the groove 1b is increased). Therefore, it is possible to slow the plastic deformation of the raw tube 3 during the drawing process. Moreover, since the edge of the groove crest 1b is chamfered in a straight line, the contact area between the top of the groove crest 1b and the element tube 3 is reduced, and this occurs between the apex of the groove crest 1b and the element tube 3. The frictional resistance will be reduced. With the above configuration, the occurrence of seizure between the tool 1A and the raw tube 3 can be effectively prevented. Furthermore, since it is only necessary to chamfer the chamfered portion in a straight line, it is not necessary to prepare a plurality of grindstones when the tool 1A is manufactured, and the chamfered portion can be easily and inexpensively manufactured.

  Furthermore, as a tool according to the present invention, a tool 1B as shown in FIG. 6 may be employed. FIG. 6 is a side view illustrating a schematic configuration of the tool according to the present embodiment. FIG. 7 is a schematic diagram showing a partially enlarged cross-sectional shape perpendicular to the tool axis with respect to one groove crest and one spiral groove intersecting with the tool axis shown in FIG. ) Is a sectional view taken along the arrow DD in FIG. 6, (b) is a sectional view taken along the arrow EE in FIG. 6, and (c) is a sectional view taken along the arrow FF in FIG. FIG. 8 is a plan view of a first straight line passing through each top of the groove mountain in each cross section shown in FIG. 7 and a second straight line passing through each bottom of the spiral groove (viewed from above in FIG. 6). Figure). As shown in FIG. 7, the tool 1 </ b> B according to the present embodiment is also chamfered in a straight line at the edge of one groove mountain 1 b that intersects the axis of the tool 1 in a side view, similarly to the tool 1 </ b> A shown in FIG. 4. It is characterized by being. However, unlike the tool 1A shown in FIG. 4, the first straight line L1 passing through the top portions 1ba, 1bb, 1bc excluding the tip portion of the tool 1 in the groove 1b extends from the tip portion side to the rear end portion side of the tool 1A. Inwardly (in a direction approaching the axis) and passes through the bottoms 1aa, 1ab, 1ac except for the tip of the tool 1 of one spiral groove 1a that intersects the axis of the tool 1A in a side view. There is no constraint that the angle θ1 formed by the first straight line L1 with respect to the axial direction of the tool 1A is set larger than the angle θ2 formed by the second straight line L2 with respect to the axial direction of the tool 1A. In the tool 1B according to the present embodiment, θ1 = θ2 = 0 ° is set.

  Also in the tool 1B according to the present embodiment, since the edge of the groove 1b is chamfered in a straight line, the contact area between the top of the groove 1b and the raw tube 3 is reduced. The frictional resistance generated between the pipe 3 and the pipe 3 is reduced, and as a result, the occurrence of seizure between the tool 1B and the base pipe 3 can be effectively prevented. Further, since the chamfered portion only needs to be chamfered linearly, it is not necessary to prepare a plurality of grindstones when the tool 1B is manufactured, and the chamfered portion can be easily and inexpensively manufactured.

The tools 1, 1 </ b> A, and 1 </ b> B described above are manufactured through the following sequential steps. That is,
(1) Molding step: Step of compression molding the raw material powder of the tool (2) Sintering step: Step of heating and firing the molded product obtained by the compression molding (3) Grinding step: Molded product after the heating and firing (4) Edge polishing process: process of chamfering the edge of the groove crest in a curved or linear shape using a grindstone (5) Overall polishing process: the entire tool to a specified roughness It is manufactured through each step of polishing.

  Table 1 shows an example of the results of evaluating the occurrence of seizure and the manufacturing cost when used in the drawing process for the tool according to the present invention and the tool according to the comparative example described above. In Table 1, no. 2 to 5 correspond to the tools according to the present invention. 1 and 6 are tools according to a comparative example.

  More specifically, no. 2 is set to θ1 (3 °)> θ2 (0 °), and the edge of the groove is chamfered in a curved shape with a constant radius of curvature of 0.3 mm, which will be described with reference to FIG. It corresponds to the tool 1 made. No. The tool No. 3 is set to θ1 (3 °)> θ2 (0 °), and the edge of the groove is linearly chamfered, and corresponds to the tool 1A described with reference to FIG. No. In the tool No. 4, θ1 (5 °)> θ2 (3 °) is set, and the edge of the groove is linearly chamfered, and θ2 ≠ 0 ° in the tool 1A described with reference to FIG. Is equivalent to Furthermore, no. The tool No. 5 is set to θ1 (0 °) = θ2 (0 °), and the edge of the groove is linearly chamfered, and corresponds to the tool 1B described with reference to FIG. On the other hand, no. 1 is set to θ1 (0 °) = θ2 (0 °), and the radius of curvature of the chamfer groove edge to be chamfered is changed stepwise within the range of 0.3 to 10 mm (the tool The tool is enlarged stepwise from the front end side to the rear end side. No. The tool No. 6 is a tool in which θ1 (0 °) = θ2 (0 °) is set, and the edge of the groove is not chamfered.

The numerical values described in the column “Manufacturing cost” shown in Table 1 are No. 6 shows how much the manufacturing cost of each tool rises with respect to the manufacturing cost of the six tools. For example, no. No. 1 tool no. The manufacturing cost increases at a rate of 50% with respect to the No. 6 tool. This means that 1.5 times the manufacturing cost is required for 6 tools. The manufacturing cost shown in Table 1 is a value calculated based on the following factors. That is,
(1) Machining so that θ1 is greater than 0 °: 10% increase (2) Machining so that both θ1 and θ2 are greater than 0 °: 15% increase (3) Chamfering linearly: 10% increase (4) Chamfering to a curved line (constant curvature radius): 20% increase (5) Chamfering to a curved line (curvature radius change): Value calculated based on each factor of 50% increase. For example, no. In the tool of No. 2, the manufacturing cost increases by 10% due to the factor (1), and also increases by 20% due to the factor (4). Therefore, the manufacturing cost increases by 30% in total.

  As shown in Table 1, with respect to the tool according to the comparative example, instead of being able to prevent the occurrence of seizure, there is a problem that the manufacturing cost rises (No. 1 tool), or instead the manufacturing cost can be suppressed. The problem that seizure occurs during the drawing process (No. 6 tool) occurs. On the other hand, for the tool according to the present invention (No. 2 to 5), it is possible to prevent the occurrence of seizure at the time of drawing, and to suppress the manufacturing cost, and as a rifle tube drawing tool It has been found suitable.

FIG. 1 is a side view schematically showing a state in which a blank pipe is drawn using a rifle tube drawing tool according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing a partially enlarged cross-sectional shape perpendicular to the tool axis, with respect to one groove crest and one spiral groove intersecting with the tool axis shown in FIG. 1 is a cross-sectional view taken along arrow AA in FIG. 1, (b) is a cross-sectional view taken along arrow BB in FIG. 1, and (c) is a cross-sectional view taken along arrow CC in FIG. FIG. 3 is a plan view of a first straight line that passes through each top of the groove crest in each cross section shown in FIG. 2 and a second straight line that passes through each bottom of the spiral groove. FIG. 4 is a schematic diagram showing a partially enlarged cross-sectional shape perpendicular to the tool axis for one groove crest and one spiral groove intersecting with the tool axis according to another embodiment of the present invention. (A) is sectional drawing of the front end side of a tool, (b) is sectional drawing of the axial direction intermediate part of a tool, (c) shows sectional drawing of the rear end side of a tool. FIG. 5 shows a plan view of a first straight line passing through each top of the groove crest in each cross section shown in FIG. 4 and a second straight line passing through each bottom of the spiral groove. FIG. 6 is a side view illustrating a schematic configuration of a tool according to still another embodiment of the present invention. FIG. 7 is a schematic diagram showing a partially enlarged cross-sectional shape perpendicular to the axis of the tool with respect to one groove crest and one spiral groove intersecting with the axis of the tool shown in FIG. 6 is a cross-sectional view taken along arrow DD in FIG. 6, (b) is a cross-sectional view taken along arrow EE in FIG. 6, and (c) is a cross-sectional view taken along arrow FF in FIG. 6. FIG. 8 shows a plan view of a first straight line passing through each top of the groove crest in each cross section shown in FIG. 7 and a second straight line passing through each bottom of the spiral groove.

Explanation of symbols

1, 1A, 1B ... Tool 1a ... Spiral groove 1b ... Groove mountain 2 ... Die 3 ... Elementary tube

Claims (4)

A rifle tube drawing tool that is inserted into the inner surface of an element pipe that is drawn while being squeezed by a die, and has a plurality of spiral grooves formed on the outer peripheral surface thereof.
In a side view, a first straight line passing through the top of the groove that intersects the axis of the tool excluding the tip of the tool is inclined inward from the tip end side to the rear end side of the tool. And the second straight line passing through the bottom excluding the tip of the tool in one spiral groove intersecting the axis of the tool in a side view, than the angle formed with respect to the axis direction of the tool in a plan view, The angle formed by the first straight line with respect to the axial direction of the tool in plan view is set to be larger, and the edge of the one groove is chamfered in an outwardly convex curved shape, and its radius of curvature is Is set to a constant value from the front end portion to the rear end portion of the tool, the rifle tube drawing tool. A rifle tube drawing tool that is inserted into the inner surface of an element pipe that is drawn while being squeezed by a die, and has a plurality of spiral grooves formed on the outer peripheral surface thereof.
In a side view, a first straight line passing through the top of the groove that intersects the axis of the tool excluding the tip of the tool is inclined inward from the tip end side to the rear end side of the tool. And the second straight line passing through the bottom excluding the tip of the tool in one spiral groove intersecting the axis of the tool in a side view, than the angle formed with respect to the axis direction of the tool in a plan view, The rifle tube is characterized in that an angle formed by the first straight line with respect to the axial direction of the tool in plan view is set to be larger, and an edge of the one groove is linearly chamfered. Drawing tool. A rifle tube drawing tool that is inserted into the inner surface of an element pipe that is drawn while being squeezed by a die, and has a plurality of spiral grooves formed on the outer peripheral surface thereof.
A rifle tube drawing tool characterized in that an edge of a groove groove intersecting the axis of the tool in a side view is chamfered linearly.   A method for producing a rifle tube comprising a step of drawing a rifle tube drawing tool according to any one of claims 1 to 3 while drawing the tie tube with a die while the rifle tube drawing tool is inserted into the inner surface of the tube. Method.

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