JP6080800B2 - Manufacturing method of eccentric tube - Google Patents

Description

  The present invention relates to a method of manufacturing an eccentric tube.

  Conventionally, there are methods described in Patent Documents 1 and 2 as manufacturing methods of the eccentric tube.

  The manufacturing method of an eccentric tube expansion described in Patent Document 1 forms an eccentric tube expansion by press-fitting the center axis of the tube expansion punch with a shift from the center axis of the element tube. At this time, it has been proposed to use a plurality of tube expansion punches having different maximum diameters and perform tube expansion processing in a plurality of stages.

  The manufacturing method of the eccentric pipe expansion described in Patent Document 2 is a processing pipe formed by expanding the pipe end of the raw pipe to the intermediate pipe expansion stage and coaxially from the neck portion with the raw pipe diameter to the intermediate pipe expansion section. A coaxial pipe expanding step, moving the neck in the radial direction, decentering the central axis of the neck and the central axis of the pipe expanded portion, and using a pipe having a larger diameter than the coaxial pipe expanding step, And an eccentric tube expansion step of expanding the intermediate tube expansion portion to the final tube expansion portion.

Japanese Patent Laid-Open No. 11-239835 JP 2006-272350 A

  In the manufacturing method of the eccentric tube expansion described in Patent Document 1, when the tube expansion process is performed in one stage, a portion having a large elongation in the circumferential direction in the tube expansion portion (in the axial direction of the tube, the outer diameter of the final tube expansion portion is Cracks were generated in the tube peripheral wall portion on the side of promoting eccentricity that would be farthest from the central axis. When tube expansion was performed in multiple stages, work hardening occurred and even larger cracks occurred.

  In the method of manufacturing the eccentric tube expansion described in Patent Document 2, although cracks in the tube expansion portion were settled, wrinkles were generated.

  The subject of this invention is aiming at equalizing the elongation of the circumferential direction in a pipe expansion part as much as possible, and manufacturing an eccentric pipe with an excellent shape.

  The invention according to claim 1 is a method of manufacturing an eccentric tube that forms an expanded tube portion eccentric from the central axis of the tube at the tube end, and a prior tube expanding step in which the tube end of the tube is expanded to an intermediate tube expansion stage by a preceding punch. In the final process, the intermediate tapered portion connected to the neck portion with the raw tube diameter and the intermediate expanded portion connected to the intermediate tapered portion are formed, and the processed tube is expanded to the final expanded stage by the final punch. When forming the intermediate taper portion and the intermediate pipe expansion portion of the processed pipe into the final taper portion having the final curvature of the pipe peripheral wall and the final pipe expansion portion connected to the final taper portion in the pipe expansion process, When the outer diameter of the final tube expansion part is the farthest distance from the central axis of the tube, the side where the outer diameter is the acceleration promoting side and the side opposite the diametrical direction is the eccentricity suppression side, By using The expanded pipe portion and the curvature of the intermediate tapered portion, with respect to the final curvature to be imparted to the final expanded portion and a final taper portion, an eccentric suppressing side is obtained by such processing as to approximate than the eccentric accelerator side.

  The invention according to claim 2 is the invention according to claim 1, wherein the preceding punch further includes a tip portion, a truncated cone portion, and a main body portion, and the tip portion has a cylindrical shape with an outer diameter matching the inner diameter of the raw tube. None, the frustoconical part has a frustoconical shape with an outer diameter that matches the planned inner diameter of the intermediate tapered part, and the main body part has a cylindrical shape with an outer diameter that matches the planned inner diameter of the intermediate expanded part, the tip part The truncated cone part and the main body part are arranged such that one side ridge line of the truncated cone part and main body part is collinear with one side ridge line of the tip part, or one side ridge line of the truncated cone part and body part is one side of the tip part. Each axial center is eccentric so that it is outside the ridgeline, the final punch has a tip portion, a truncated cone portion, and a body portion, and the tip portion has a cylindrical shape with an outer diameter that matches the inner diameter of the raw tube. None, the frustoconical part has a frustoconical shape with an outer diameter that matches the planned inner diameter of the final taper part, and the main body part is planned to expand the final pipe expansion part It has a cylindrical shape with an outer diameter that matches the diameter, and the tip portion, the truncated cone portion, and the main body portion are arranged so that one side ridge line of the truncated cone portion and the main body portion is collinear with one side ridge line of the tip portion, or the truncated cone The center axis of each of the head part and the main body part is eccentric so that the one side ridge line is outside the one side ridge line of the tip part.

  (a) Focusing on the tube wall on the eccentricity suppression side, which tends to be smaller in the circumferential direction than the other part (the tube wall on the eccentricity promotion side) that should be given until the final tube expansion process is completed. In the preceding pipe expanding process using the leading punch, the diameter of the pipe peripheral wall part on the eccentricity suppressing side in the intermediate pipe expanding part and the intermediate taper part of the processed pipe is greatly expanded to approximate the final curvature to be given in the final pipe expanding process. To do. As a result, in each cross section of the intermediate expanded portion and the intermediate tapered portion of the processed tube, the material on the eccentricity suppression side actively projects toward both sides in the circumferential direction continuing to the eccentricity promotion side by the end of the preceding tube expansion process. And become fluid.

  (b) Therefore, in the final pipe expansion process using the final punch, the entire circumference including the pipe peripheral wall part (the part where the elongation in the circumferential direction increases) of the processed pipe is increased so as to match the final curvature. In this case, in each cross section of the intermediate tube expansion portion and the intermediate taper portion of the processed tube, the material that has already flowed in from the eccentricity suppression side is used for elongation on the eccentricity promotion side, and the eccentric tube expansion molding proceeds smoothly. Thereby, the elongation in the circumferential direction in the expanded portion can be made as uniform as possible, and an eccentric expanded tube having an excellent shape can be manufactured.

FIG. 1 is a schematic view showing a tube expansion press. FIG. 2 is a schematic view showing a tube expansion mold apparatus. FIG. 3 is a schematic diagram showing the tube expansion process. FIG. 4 is a schematic diagram showing the final shape of the eccentric tube expansion. FIG. 5 is a schematic diagram showing a leading punch. FIG. 6 is a schematic diagram showing the final punch. FIG. 7 is a schematic diagram showing a prior pipe expansion process. FIG. 8 is a schematic diagram showing the final tube expansion process.

  A tube expansion press 100 shown in FIG. 1 has a bed 101 and a ram 102 that moves up and down relative to the bed 101. The ram 102 may be moved up and down by any power such as a hydraulic type, a mechanical type, and a servo motor type.

  A mold apparatus 200 is attached to and detached from the press machine 100. The mold apparatus 200 has a lower base 201 fixed to the bed 101 and an upper base 202 fixed to the ram 102.

  The lower base 201 of the mold apparatus 200 is slidably juxtaposed on a guide race corresponding to the first and second cam slides 211 and 212, and the leading punch 10 is attached to the first cam slide 211, The final punch 20 is attached to the second cam slide 212. The lower base 201 is arranged in front of the first and second cam slides 211 and 212 (front along the axial direction of the punches 10 and 20 attached to the cam slides 211 and 212). Lower molds 213 and 214 are fixedly juxtaposed.

  In the upper base 202 of the mold apparatus 200, first and second drivers 221 and 222 are fixedly juxtaposed at positions above the first and second cam slides 211 and 212. The upper base 202 has the first and second upper molds 223 and 224 juxtaposed in front of the first and second drivers 221 and 222 and above the first and second lower molds 213 and 214. I am letting. At this time, the upper base 202 supports the first and second upper molds 223 and 224 via the gas springs 223A and 224A.

  The press machine 100 (A) forms the processed tube 2 (FIG. 3B) from the raw tube 1 (FIG. 3A) in the preceding tube expansion process using the preceding punch 10, and (B) uses the final punch 20. In the final tube expanding step, the eccentric tube 3 (FIGS. 3C and 4) is formed from the processed tube 2. The eccentric tube 3 is formed by forming the final tube expansion portion 3 </ b> A (center shaft f), which is eccentric (the amount of eccentricity e) from the center axis c of the tube 1, at the tube end of the tube 1.

  That is, the press machine 100 includes an intermediate taper portion 2T connected to a cylindrical neck portion 1N having the same diameter as the raw tube 1 in a pre-expansion step in which the tube end of the raw tube 1 is expanded to the intermediate expansion stage by the preceding punch 10. Then, a processed tube 2 is obtained in which a cylindrical intermediate tube expansion portion 2A connected to the intermediate taper portion 2T is formed. The press machine 100 is a final tube expansion process in which the processed tube 2 is expanded to the final tube expansion stage by the final punch 20, and the final taper of the intermediate taper portion 2T of the processed tube 2 and the pipe peripheral wall of the intermediate expanded portion 2A is final. The eccentric expanded tube 3 formed up to the tapered portion 3T and the cylindrical final expanded portion 3A connected to the final tapered portion 3T is obtained. In the tube expansion process of forming the eccentric tube 3 at the tube end of the tube 1 by the press machine 100, the outer diameter of the final tube expansion portion 3 </ b> A is farthest from the center axis c of the tube 1 as viewed in the axial direction of the tube 1. It is assumed that the eccentric side is the eccentricity promoting side K and the opposite side in the diameter direction is the eccentricity suppressing side L (FIG. 7).

  In the present embodiment, the processed tube 2 includes the intermediate expanded portion 2A, the intermediate tapered portion 2T, and one side ridge line of the raw tube 1 (the outer diameter of the intermediate expanded portion 2A in the axial direction of the raw tube 1 is 1). The opposite side in the diametrical direction with respect to the side farthest from the central axis c is called one side). Further, the eccentric pipe 3 has a final pipe part 3A, a final taper part 3T, and one side ridge line of the raw pipe 1 (the outer diameter of the final pipe part 3A is from the central axis c of the pipe 1 in the axial direction of the pipe 1). The opposite side of the diametrical direction with respect to the most distant side is called one side).

  As shown in FIG. 5, the leading punch 10 has a tip portion 10N, a truncated cone portion 10T, and a main body portion 10A. The distal end portion 10N has a cylindrical shape with an outer diameter that matches the inner diameter of the raw tube 1. The truncated cone portion 10T has a truncated cone shape having an outer diameter that matches the planned inner diameter of the intermediate taper portion 2T of the processing tube 2. The main body portion 10 </ b> A has a cylindrical shape with an outer diameter that matches the planned diameter expansion of the intermediate tube expansion portion 2 </ b> A of the processed tube 2. The distal end portion 10N, the truncated cone portion 10T, and the main body portion 10A are formed from one side ridge line of the truncated cone portion 10T and the main body portion 10A (the outer diameter of the main body portion 10A is the center of the distal end portion 10N in the axial direction of the leading punch 10). The opposite side in the diametrical direction with respect to the side farthest from the axis i is referred to as one side) and is set so as to be collinear with the one side ridge line of the tip portion 10N.

  As shown in FIG. 6, the final punch 20 has a tip 20N, a truncated cone 20T, and a main body 20A. The distal end portion 20N has a cylindrical shape with an outer diameter that matches the inner diameter of the raw tube 1. The truncated cone portion 20T has a truncated cone shape having an outer diameter that matches the planned diameter expansion of the final tapered portion 3T of the eccentric tube 3. The main body portion 20 </ b> A has a cylindrical shape with an outer diameter that matches the planned inner diameter of the final expanded portion 3 </ b> A of the eccentric expanded tube 3. The distal end portion 20N, the truncated cone portion 20T, and the main body portion 20A are arranged on one side of the truncated cone portion 20T and the main body portion 20A (the outer diameter of the main body portion 20A is the central axis of the distal end portion 20N in the axial direction of the final punch 20). The side opposite to the diametrical direction with respect to the side farthest from j is called one side) and is set so as to be collinear with the one side ridge line of the tip 20N.

(A) Advance pipe expansion process 8 (Fig. 7)
(1) The leading punch 10 is attached to the first cam slide 211 provided in the lower base 201 of the mold apparatus 200 already assembled in the bed 101 of the press machine 100 (FIG. 7A). Then, the tube end of the raw tube 1 is set in the first lower mold 213 provided in the lower base 201 (FIG. 7A).

  (2) Lowering the ram 102 of the press machine 100, aligning the upper mold 223 provided in the upper base 202 of the mold apparatus 200 incorporated in the ram 102 with the lower mold 213, The tube end of the raw tube 1 is clamped between the upper mold 223 (FIG. 7B). The tube end of the raw tube 1 is clamped by an upper mold 223 and a lower mold 213 that are pressurized by a gas spring 223A.

  In the mold apparatus 200, the lower mold 213 and the upper mold 223 are in a state of being in contact with each other and are in contact with the neck 1N of the raw tube 1, and the intermediate tapered portion 2T and the intermediate expanded portion 2A of the processed tube 2 are used. The inner surface of the mold is formed so that each outer peripheral surface of the mold can be molded.

  (3) In the process until the ram 102 of the press machine 100 is further lowered and the gas spring 223A reaches the compression end, the downward slope of the driver 221 provided in the upper base 202 is the first cam slide 211 on the lower base 201. When hitting the upward slope, the first cam slide 211 slides forward on the guide rail of the lower base 201. As a result, the leading punch 10 attached to the first cam slide 211 moves forward, and the inner diameter portion of the tube end of the base tube 1 clamped between the lower mold 213 and the upper mold 223. It is pushed into. The leading end portion 10N, the truncated cone portion 10T, and the main body portion 10A of the leading punch 10 are sequentially pushed into the inner diameter portion of the tube end of the element tube 1, and at the pushing end, the tip end portion 10N reaches the neck portion 1N of the element tube 1. The truncated cone portion 10T forms the intermediate tapered portion 2T of the processed tube 2, and the main body portion 10A forms the intermediate expanded portion 2A of the processed tube 2 to obtain the processed tube 2 (FIG. 7C).

  In the preceding tube expanding step, the leading punch 10 determines the curvature ρ2 of the intermediate tapered portion 2T of the processed tube 2 formed by the truncated cone portion 10T and the intermediate expanded portion 2A of the processed tube 2 formed by the main body portion 10A. The final curvature ρ3 planned for the final tapered portion 3T and the final expanded portion 3A of the eccentric tube 3 is processed on the eccentricity suppression side L to be more approximate than on the eccentricity promotion side K. That is, as shown in FIG. 3, the curvature ρ2L (FIG. 3B) on the eccentric taper side 2T of the processed pipe 2 and the eccentric pipe expansion part 2A is the final taper part 3T of the eccentric pipe 3 and the final pipe expansion part. The diameter is greatly expanded so as to be close to the final curvature ρ3 (FIG. 3C) scheduled for 3A. The curvature ρ2K (FIG. 3B) on the eccentric acceleration side K of the intermediate tapered portion 2T and the intermediate expanded portion 2A of the processed tube 2 is not greatly expanded, and the final tapered portion 3T and the final expanded portion 3A of the eccentric expanded tube 3 are scheduled. This is far from the final curvature ρ3 (FIG. 3C).

(B) Final tube expansion process (Figure 8)
(1) The final punch 20 is attached to the second cam slide 212 provided in the lower base 201 of the mold apparatus 200 already assembled in the bed 101 of the press machine 100 (FIG. 8A). Then, the processed tube 2 that has been processed in the preceding tube expansion process is set in the second lower mold 214 provided in the lower base 201 (FIG. 8A).

  (2) Lowering the ram 102 of the press machine 100, aligning the second upper mold 224 provided in the upper base 202 of the mold apparatus 200 incorporated in the ram 102 with the lower mold 214, and lowering the lower mold The processing tube 2 is clamped between the mold 214 and the upper mold 224 (FIG. 8B). The processing tube 2 is clamped by an upper die 224 and a lower die 214 that are pressurized by a gas spring 224A.

  In the mold apparatus 200, the lower mold 214 and the upper mold 224 are in a state of being in contact with each other, and are in contact with the neck 1N of the base tube 1, and the final taper portion 3T and the final pipe expansion portion 3A of the eccentric tube 3. The inner surface of the mold is formed so that each outer peripheral surface to which the final curvature is given can be formed.

  At this time, the intermediate taper portion 2T and the intermediate tube expansion portion 2A on the eccentricity suppressing side L of the processed tube 2 are expanded to the vicinity of the final curvature in the preceding tube expansion process, and in this embodiment, generally on the mold curved surface of the upper mold 224. Match.

  (3) The downward slope of the driver 222 included in the upper base 202 is the upward slope of the cam slide 212 on the lower base 201 until the ram 102 of the press 100 is further lowered and the gas spring 224A reaches the compression end. When hitting, the cam slide 212 slides forward on the guide rail of the lower base 201. As a result, the final punch 20 attached to the cam slide 212 moves forward and is pushed into the inner diameter portion of the processing tube 2 clamped between the lower mold 214 and the upper mold 224. The tip 20N, the truncated cone 20T, and the main body 20A of the final punch 20 are sequentially pushed into the inner diameter of the processing tube 2, and at the pushing end, the tip 20N reaches the neck 1N of the raw tube 1 and the truncated cone. 20T forms the final taper portion T of the eccentric tube 3 and the main body 20A forms the final tube portion 3A of the eccentric tube 3 to obtain the eccentric tube 3 (FIG. 8C). In addition, the above-mentioned (A) preceding pipe expansion process and (B) final pipe expansion process by the press machine 100 are performed in parallel.

According to the present embodiment, the following operational effects can be obtained.
(a) The circumferential wall portion of the eccentricity suppression side L, which tends to be smaller in the circumferential direction than the other portion (the circumferential wall portion of the eccentricity promotion side K) with respect to the raw tube 1 before the completion of the final tube expansion process. In the preceding pipe expanding step using the leading punch 10, the pipe peripheral wall portion on the eccentricity suppressing side L in the intermediate pipe expanding portion 2A and the intermediate tapered portion 2T of the processed pipe 2 is subjected to the final curvature to be provided in the final pipe expanding step. The diameter is greatly expanded so as to approximate to. Thereby, in each cross section of the intermediate expanded portion 2A and the intermediate tapered portion 2T of the processed tube 2, the material on the eccentricity suppression side L is directed toward both sides in the circumferential direction continuing to the eccentricity promotion side K by the end of the preceding tube expansion process. It will be actively projected and fluidized.

  (b) Therefore, in the final tube expansion process using the final punch 20, the entire circumference including the tube peripheral wall portion (the portion where the elongation in the circumferential direction increases) on the eccentricity promoting side K of the processed tube 2 matches the final curvature. When the diameter is expanded, in each cross section of the intermediate expanded portion 2A and the intermediate tapered portion 2T of the processed tube 2, the material that has already flowed from the eccentricity suppression side L is used for the extension on the eccentricity promotion side K, thereby smoothly performing the eccentric tube expansion molding. It will make it progress. Thereby, the elongation in the circumferential direction in the expanded portion is made as uniform as possible, and the eccentric expanded tube 3 having an excellent shape is manufactured.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration of the present invention is not limited to this embodiment, and even if there is a design change or the like without departing from the gist of the present invention. It is included in the present invention. For example, in the present invention, the processed tube 2 is formed so that the one side ridge line of the intermediate tube expansion portion 2A and the intermediate taper portion 2T is positioned outside the one side ridge line of the element tube 1, and the eccentric tube expansion 3 is The one side ridge line of the expanded pipe portion 3 </ b> A and the final taper portion 3 </ b> T may be formed so as to be located outside the one side ridge line of the raw tube 1. In the preceding punch 10 corresponding to this, the axial centers of the truncated cone part 10T and the main body part 10A are eccentric so that the one side ridge line of the front part 10N is outside the one side ridge line of the tip part 10N. In this case, the axial centers of the truncated cone part 20T and the main body part 20A are eccentric so that the one side ridge line is outside the one side ridge line of the tip part 20N.

  In the present invention, the preceding pipe expansion process may be divided into a plurality of stages of two or more stages, and a plurality of preceding punches having different maximum diameters may be used in each stage. At each stage of the preceding tube expansion process, the curvature of the intermediate tube expansion portion and the intermediate taper portion is gradually brought close to the final curvature to be applied to the final tube expansion portion and the final taper portion. And in each stage of this preceding pipe expansion process, the curvature of the intermediate pipe expansion part and the intermediate taper part is more on the eccentricity suppression side L and on the eccentricity promotion side K than the final curvature to be given to the final pipe expansion part and the intermediate taper part. Is also approximated.

  In addition, the eccentric tube expansion manufacturing apparatus used for implementation of this invention is not restricted to what sets the die apparatus 200 to the press machine 100 so that attachment or detachment is possible, and may consist of a dedicated machine.

  ADVANTAGE OF THE INVENTION According to this invention, the equal expansion of the circumferential direction extension in a pipe expansion part is achieved as much as possible, and the eccentric pipe expansion of the excellent shape can be manufactured.

DESCRIPTION OF SYMBOLS 1 Elementary pipe 1N Neck part 2 Processing pipe 2A Intermediate expansion part 2T Intermediate taper part 3 Eccentric expansion part 3A Final expansion part 3T Final taper part 10 Predecessor punch 10A Main part 10N Front end part 10T Frustum part 20 Final punch 20A Main part 20N Front end part 20T Frustum part K Eccentricity promotion side L Eccentricity suppression side

Claims (2)

In the manufacturing method of the eccentric pipe expanding the pipe expansion part eccentric from the central axis of the raw pipe at the pipe end,
A processed pipe that is formed with an intermediate taper part that is connected to the neck part of the raw pipe diameter and an intermediate pipe part that is connected to the intermediate taper part in the prior pipe expansion process in which the pipe end of the raw pipe is expanded to the intermediate pipe expansion stage using a preceding punch. As well as
In the final tube expansion process of expanding the processed tube to the final expansion stage by the final punch, the intermediate taper portion and the intermediate expanded portion of the processed tube are connected to the final taper portion whose peripheral wall is the final curvature and the final taper portion. When forming the final expanded pipe
When the outer diameter of the final tube expansion portion is the most distant from the central axis of the tube when viewed from the axial direction of the tube, it is the eccentricity promoting side, and the opposite side of the diameter direction is the eccentricity suppressing side,
By using a leading punch in the preceding tube expansion step, the curvature of the intermediate tube expansion portion and the intermediate taper portion is set to the eccentricity suppression side, compared to the eccentricity promotion side with respect to the final curvature to be applied to the final tube expansion portion and the final taper portion. A method of manufacturing an eccentric tube, which is processed so as to approximate. The preceding punch has a tip portion, a truncated cone portion, and a main body portion, the tip portion has a cylindrical shape with an outer diameter that matches the inner diameter of the raw tube, and the truncated cone portion matches the planned diameter increase of the intermediate taper portion. It has a frustoconical shape with an outer diameter, the main body portion has a cylindrical shape with an outer diameter that matches the planned inner diameter of the intermediate tube expansion portion, and the tip, the truncated cone portion, and the main body portion are one of the truncated cone portion and the main body portion. The axis of each other is decentered so that the side ridge line is the same line as the one side ridge line of the tip part, or the one side ridge line of the truncated cone part and the main body part is outside the one side ridge line of the tip part,
The final punch has a tip portion, a truncated cone portion, and a main body portion. The tip portion has a cylindrical shape with an outer diameter that matches the inner diameter of the raw tube, and the truncated cone portion matches the expected diameter increase of the final tapered portion. It has a frustoconical shape with an outer diameter, the main body portion has a cylindrical shape with an outer diameter that matches the planned inner diameter of the final expanded portion, and the tip, the truncated cone portion, and the main body portion are one of the truncated cone portion and the main body portion. Claims wherein the side ridge line is the same line as the one side ridge line of the tip part, or the axes of each other are eccentric so that the one side ridge line of the truncated cone part and the main body part is outside the one side ridge line of the tip part. Item 2. A method for producing an eccentric tube according to Item 1.

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