JP6695589B2 - Tube expansion device - Google Patents

Description

  The present invention relates to a pipe expanding device for expanding an opening portion of a metal pipe.

  BACKGROUND ART Conventionally, for example, a tube expanding device disclosed in Patent Document 1 includes a clamp type for fixing a metal tube and a punch type capable of press-fitting into the metal tube fixed to the clamp type from one of the openings. A plurality of punch dies having different outer sizes are prepared. Then, the punch dies are press-fitted in order from the one having the smallest outer diameter through one opening of the metal tube, and one side of the metal tube is gradually expanded outward in the outer peripheral surface of each of the punch dies to cause cracking or cracking. The metal tube is expanded into a desired shape without causing cracks.

JP, 2010-227988, A

  However, since the pipe expanding device of Patent Document 1 expands the metal pipe by using a plurality of punch dies, the punch dies to be used are sequentially moved to the press-fitting start position with respect to the metal pipe, and the central axis of the punch dies to be used. There is a problem in that the operation is required to coincide with the cylinder center line of the metal tube, the structure is complicated and the cost increases, and the processing time becomes long.

  In order to avoid this, it is possible to reduce the number of punch dies, but if the number of punch dies is simply reduced, the elongation of the base material of the metal tube cannot follow the amount by which the punch die stretches the metal tube. There is a risk that cracks and cracks will occur frequently.

  The present invention has been made in view of such points, and an object of the present invention is to provide a pipe expanding device that does not cause cracks or cracks in a metal pipe, is low in cost, and has a short processing time. To provide.

  In order to achieve the above object, the present invention performs a pipe expanding process by utilizing a phenomenon in which a metal tube heated to a temperature higher than room temperature and lower than a recrystallization temperature softens as compared with a case where the temperature is the same as room temperature. It is characterized by doing so.

  That is, according to the first aspect of the present invention, a fixing portion that contacts the outer peripheral surface of the metal pipe on one end side to fix the metal pipe and a metal pipe that is provided continuously to the fixing portion and is fixed to the fixing portion. A clamp die having a non-fixed portion that forms a gap in the circumferential direction between the end side outer peripheral surface, and a punch die provided so as to be press-fitted from the other end opening into the metal tube fixed to the clamp die. A heating means capable of heating the punch die, wherein the heating means heats the punch die to a temperature higher than room temperature and lower than a recrystallization temperature and press-fitted into the metal tube through the other end opening. Thus, the punch die is configured to expand the other end side of the metal tube radially outward until it extends along the non-fixed portion to expand the tube.

  A second invention is characterized in that, in the first invention, a cooling means capable of cooling the clamp die is provided.

  In a third aspect based on the second aspect, the cooling means comprises a pipe provided in a portion of the clamp type excluding the fixing portion, and a circulation means for circulating a cooling medium in the pipe. The portion is formed of a ceramic material.

  In the first invention, when the punch die is pressed into the metal tube, the metal tube is heated by the punch die in the heated state, and the temperature of the metal tube becomes higher than room temperature and lower than the recrystallization temperature. Therefore, the metal tube becomes softer than when it is at the same temperature as room temperature, and even if the punch die pushes the metal tube outward in the radial direction, the plate thickness of the metal tube does not become too thin, and the metal tube is cracked. It is possible to make it hard to generate cracks. Further, since it is possible to perform pipe expanding without cracks or cracks in the metal pipe without using many punch dies, it is possible to reduce the number of punch dies used when expanding the metal pipe. Therefore, in the tube expanding device, the number of operations such as sequentially moving the punch die to be used to the press-fitting start position with respect to the metal tube or aligning the center axis of the punch die to be used with the center line of the metal tube is reduced. The structure is simpler than the structure of the device as in Patent Document 1, the cost can be kept low, and the processing time can be shortened.

  In the second invention, when the other end side of the metal pipe is pushed outward by the punch die in the radial direction and comes into contact with the non-fixed portion during the pipe expanding process, the pipe expanded portion of the metal pipe in the heated state is cooled. It is rapidly cooled by the fixed part. Therefore, the amount of heat shrinkage in the expanded portion of the metal pipe is reduced, the occurrence of wrinkles and the like is suppressed, and the processing accuracy of the expanded portion can be improved.

  In the third aspect of the invention, since the fixing portion has a low thermal conductivity, the metal tube fixed to the fixing portion is less likely to be cooled even when the clamp die is cooled by the cooling means. Therefore, when the punch die is pressed into the metal tube, the temperature of the metal tube can be raised to a desired temperature in a short time by the heat of the punch die, and the metal tube is higher than room temperature and lower than the recrystallization temperature in the process of pipe expanding. The temperature can be assured.

It is a cross-sectional schematic diagram of the tube expansion apparatus which concerns on embodiment of this invention. It is a figure which shows the state which expanded the metal tube by press-fitting the punch type | mold into the metal tube fixed to the fixed type | mold after the state of FIG. It is a stress strain curve according to temperature of the metal pipe to process.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the following description of the preferred embodiments is merely exemplary in nature.

  1 and 2 are schematic cross-sectional views of a tube expanding device 1 according to an embodiment of the present invention. The pipe expanding device 1 is installed in a manufacturing line of a fuel oil supply pipe (not shown) incorporated in a vehicle, and is used for expanding the end portion of the metal pipe 10. The clamp die 2 fixes the metal pipe 10. Is equipped with.

  The clamp die 2 is divided into an upper die 3 and a lower die 4 each having a substantially rectangular parallelepiped shape at a position approximately in the vertical center.

  A fixing portion 30 made of a ceramic material is provided in a portion of the lower portion of the upper mold 3 extending from one end in the horizontal direction to a midway portion, and a metal having a posture in which a cylinder center line C1 is oriented in the horizontal direction on a lower surface of the fixing portion 30. A first concave surface 31 having a semicircular cross section is formed corresponding to the upper half portion of the tube 10.

  The portion of the clamp die 2 excluding the fixed portion 30 is made of steel.

  A second concave surface 32 having a semicircular cross section is formed on a portion of the lower surface of the upper mold 3 excluding the fixing portion 30.

  The second concave surface 32 has one end in the horizontal direction continuous with the first concave surface 31 and an inclined extending surface 32a extending so as to gradually increase in diameter toward the other end in the horizontal direction, and the inclined extension surface 32a. A horizontal extension surface 32b that is continuous with the other end of the output surface 32a in the horizontal direction and extends in the horizontal direction is provided.

  Since the lower mold 4 has substantially the same structure as the upper mold 3 and is only arranged so as to be vertically symmetrical in a side view, the same portion as the upper mold 3 is described. Are denoted by the same reference numerals, and detailed description will be omitted.

  A temperature sensor 16 for detecting the temperature of the lower mold 4 is embedded in the lower mold 4 near the horizontal extension surface 32b.

  Then, with the clamp die 2 opened, the metal tube 10 with the cylinder center line C1 oriented horizontally is inserted between the upper die 3 and the lower die 4 and the clamp die 2 is closed. Then, the both fixing parts 30 contact the outer peripheral surface of the middle part from one end side of the metal pipe 10 to fix the metal pipe 10.

  In addition, the second concave surface 32 of the upper mold 3 and the second concave surface 32 of the lower mold 4 constitute the non-fixed portion 12 of the present invention. In the state of being fixed to the both fixing portions 30, it has a hole shape which is continuous with the both fixing portions 30 and is open at the opposite side of the both fixing portions 30. Then, the non-fixed portion 12 forms a gap S1 in the circumferential direction between the non-fixed portion 12 and the outer peripheral surface of the other end side of the metal tube 10 without contacting the outer peripheral surface.

  A press-fitting machine 5 is arranged laterally on the non-fixing portion 12 side of the clamp die 2.

  The press-fitting machine 5 has a substantially cylindrical punch die 6 whose center axis C2 is aligned with the cylinder center line C1 of the metal tube 10 fixed to the clamp die 2, and the punch die 6 fixed to the clamp die 2. Further, a fluid pressure cylinder 7 that advances or retracts toward the metal tube 10 and a cylinder drive device 8 that drives the fluid pressure cylinder 7 are provided.

  When the punch die 6 advances toward the metal tube 10 fixed to the clamp die 2 by the fluid pressure cylinder 7, the punch die 6 is press-fitted into the metal tube 10 from the other end opening.

  In the punch die 6, a small diameter portion 6a, a molding surface portion 6b and a large diameter portion 6c are sequentially formed from the tip side of the punch die 6.

  The outer peripheral surface of the small diameter portion 6a corresponds to the inner peripheral surface of the metal tube 10, and when the punch die 6 is press-fitted into the metal tube 10, the punch die 6 is smoothly inserted into the metal tube 10. It is supposed to guide you.

  The molding surface portion 6b is provided at a position near the tip of the punch die 6, and the outer peripheral surface thereof gradually increases in diameter toward the side opposite to the press-fitting direction.

  The large-diameter portion 6c is provided from the position near the tip of the punch die 6 to the base end, and the outer peripheral surface thereof extends straight in the horizontal direction.

  The fluid pressure cylinder 7 includes a cylindrical cylinder body 71 whose center axis coincides with the center axis C2 of the punch die 6, and a cylinder chamber 70 is formed inside the cylinder body 71.

  A communication hole 71a communicating with the cylinder chamber 70 is formed in the center of one end of the cylinder body 71, and a slender rod-shaped piston rod 72 is slidably fitted in the communication hole 71a.

  One end of the piston rod 72 is fixed to the center of the base end of the punch die 6, and when the piston rod 72 slides, the punch die 6 faces the metal tube 10 fixed to the clamp die 2. To advance or retreat.

  On the other hand, a partition plate 72a extending in a direction orthogonal to the piston rod 72 is fixed to the other end of the piston rod 72.

  The partition plate 72a divides the cylinder chamber 70 into a first chamber 70a farther from the punch die 6 and a second chamber 70b closer to the punch die 6.

  The first chamber 70a is provided with a first pressure sensor 73a for detecting the pressure of the first chamber 70a, while the second chamber 70b is provided with a second pressure for detecting the pressure of the second chamber 70b. The sensor 73b is arranged.

  Further, at a position corresponding to the piston rod 72 in the second chamber 70b, an advance position detection sensor 74 for detecting the advance position of the punch die 6 by detecting the sliding amount of the piston rod 72 is arranged. ing.

  The cylinder drive device 8 has a drive device main body 81 capable of supplying or recovering a fluid, one end of which is connected to the first chamber 70a of the cylinder chamber 70 and the other end of which is connected to the drive device main body 81. One pipe 82 and a second pipe 83 having one end connected to the second chamber 70b of the cylinder chamber 70 and the other end connected to the drive device main body 81 are provided.

  The piston rod 72 supplies fluid from the drive device main body 81 to the first chamber 70a via the first pipe 82, and from the second chamber 70b to the drive device via the second pipe 83. When the fluid is collected in the main body 81, the punch die 6 is slid to one side to advance, while the fluid is supplied from the drive device main body 81 to the second chamber 70b through the second pipe 83 and at the same time. When the fluid is recovered from the first chamber 70a to the drive device main body 81 via the one pipe 82, the fluid is slid to the other side and the punch die 6 is retracted.

  The drive device main body 81 has a switching portion 81a for changing the sliding direction of the piston rod 72 by switching the supply and recovery of the fluid to the first chamber 70a and the second chamber 70b.

  A micro-heater 9 (heating means) capable of heating the punch die 6 is arranged on the side of the punch die 6.

  The micro-heater 9 includes a heater body 9a and a heating wire 9b whose temperature is adjusted by the heater body 9a, and a part of the heating wire 9b is embedded inside the punch die 6.

  A cooling water circulator 15 (cooling means) capable of cooling the clamp die 2 is arranged beside the heater body 9a.

  The cooling water circulator 15 includes a tank 15a in which cooling water is stored, a cooling pipe 15b connected to the tank 15a, and a pump 15c installed near the connection portion of the cooling pipe 15b with the tank 15a. A part of the cooling pipe 15b is embedded in a portion of the clamp die 2 excluding the fixing portion 30.

  The tank 15a and the pump 15c constitute the circulation means 15d of the present invention, and the pump 15c pumps up the cooling water accumulated in the tank 15a and circulates it through the cooling pipe 15b.

  The first pressure sensor 73a, the second pressure sensor 73b, the advancing position detection sensor 74, the cylinder drive device 8, the micro heater 9, the cooling water circulator 15, and the temperature sensor 16 include a control panel 14 (control). Means) is connected, and the control panel 14 outputs an operation signal to the cylinder drive device 8, the micro heater 9, and the cooling water circulator 15.

  The control board 14 can detect the advance position of the punch die 6 based on the detection value of the advance position detection sensor 74.

  In addition, the control board 14 sets the first pressure sensor 73a and the second pressure so that the preset pressure value at the time of press-fitting corresponding to the advance position of the punch die 6 detected by the advance-position detection sensor 74 becomes a predetermined pressure value. The pressure applied by the punch die 6 to the metal tube 10 is changed while adjusting the amount of the fluid supplied to or collected from the first chamber 70a and the second chamber 70b based on the detection value of the sensor 73b. Is becoming

  Further, the control board 14 outputs an operation signal to the heater body 9a to heat the heating wire 9b to raise the punch die 6 to a predetermined temperature.

  In addition to that, the control panel 14 circulates through the cooling pipe 15b based on the detection value detected by the temperature sensor 16 so that the temperature of the clamp die 2 reaches a predetermined set temperature during the pipe expanding process. An operation signal is output to the pump 15c so that the amount of cooling water is changed.

  Then, the control board 14 outputs an operation signal to the heater body 9a to heat the punch die 6 to a temperature higher than room temperature and lower than the recrystallization temperature, and outputs an advance start signal to the cylinder drive device 8. By pressing the punch die 6 into the metal tube 10 from the other end opening, the punch die 6 expands the other end side of the metal tube 10 to the outside in the radial direction until it extends along the non-fixed portion 12. It is designed to let you.

  FIG. 3 shows a stress-strain curve for each temperature of the metal pipe 10 to be expanded in the present invention. In the embodiment of the present invention, the punch die 6 is heated to about 200 ° C. by the micro heater 9. We are expanding pipes.

  Next, the pipe expanding process of the metal pipe 10 using the pipe expanding device 1 will be described in detail.

  First, the metal tube 10 with the cylinder center line C1 extending in the horizontal direction is inserted between the upper mold 3 and the lower mold 4 of the clamp mold 2.

  Next, as shown in FIG. 1, the clamp mold 2 is closed. Then, the fixing portion 30 of the clamp die 2 comes into contact with the outer peripheral surface of the middle portion from the one end side of the metal pipe 10 to fix the metal pipe 10.

  At this time, a gap S1 is formed between the outer peripheral surface of the metal tube 10 on the other end side and the inner peripheral surface of the non-fixed portion 12.

  Then, the pump 15c is operated to draw up the cooling water in the tank 15a and circulate the cooling water in the cooling pipe 15b.

  Further, the heater body 9a is operated to generate heat in the heating wire 9b, thereby heating the punch die 6 to bring the temperature of the punch die 6 to about 200 ° C.

  After that, the punch die 6 is advanced toward the clamp die 2. Then, first, the small diameter portion 6 a of the punch die 6 is inserted into the other end opening of the metal tube 10.

  When the punch die 6 is further advanced, the other end side of the metal tube 10 begins to be spread outward in the radial direction by the molding surface portion 6b. At this time, the temperature of the metal tube 10 is raised to about 200 ° C. by the heat of the punch die 6. In this way, when the punch die 6 is press-fitted into the metal tube 10, the punch die 6 in the heated state heats the metal tube 10 and the temperature of the metal tube 10 becomes about 200 ° C. Therefore, the metal tube 10 becomes softer than when the temperature is the same as room temperature, and even if the punch die 6 pushes the metal tube 10 outward in the radial direction, the plate thickness of the metal tube 10 does not become too thin. It is possible to make the metal tube 10 less likely to crack or crack.

  Here, since the fixing portion 30 of the clamp die 2 is formed of a ceramic material and the heat conductivity of the portion is low, even if the clamp die 2 is cooled by the cooling water circulator 15, the fixing portion 30 remains in the fixed portion 30. The metal tube 10 becomes difficult to be cooled. Therefore, when the punch die 6 is press-fitted into the metal tube 10, the heat of the punch die 6 can raise the temperature of the metal tube 10 to a desired temperature in a short time. Can be sure.

  After that, when the punch die 6 is further advanced, the other end side of the metal tube 10 is gradually expanded outwardly along the inner peripheral surface of the non-fixed portion 12 by the forming surface portion 6b of the punch die 6 and expanded. .. At this time, the expanded portion of the metal pipe 10 in the heated state comes into contact with the non-fixed portion 12 cooled by the cooling water circulator 15 and is rapidly cooled, so that the amount of heat shrinkage in the expanded portion of the metal pipe 10 decreases. Generation of wrinkles and the like can be suppressed, and the processing accuracy of the expanded portion of the metal tube 10 can be improved.

  As described above, according to the embodiment of the present invention, it is possible to prevent the metal pipe 10 from cracking or cracking by heating and softening the metal pipe during the pipe expanding process.

  Further, since it is possible to perform pipe expanding processing without cracking or cracking in the metal tube 10 without using many punch dies 6, it is possible to reduce the number of punch dies 6 used when expanding the metal pipe 10. Therefore, in the tube expanding device 1, the punch die 6 to be used is sequentially moved to the press-fitting start position for the metal tube 10, or the central axis of the punch die 6 to be used is aligned with the cylinder center line C1 of the metal tube 10. The number of times is reduced, the structure of the tube expanding device 1 becomes simpler than the structure of the device as in Patent Document 1, the cost can be kept low, and the processing time can be shortened.

  Although the fixing portion 30 is made of a ceramic material in the embodiment of the present invention, it may be made of another material, and is preferably made of a material having a low thermal conductivity.

  Further, in the embodiment of the present invention, the punch die 6 is heated by the micro heater 9, but it may be heated by another device.

  Further, in the embodiment of the present invention, the cooling water is circulated in the cooling pipe 15b, but a fluid such as oil may be circulated.

  INDUSTRIAL APPLICATION This invention is suitable for the pipe expansion apparatus which expands the opening part of a metal tube.

1 Tube expansion device 2 Clamp type 6 Punch type 9 Micro heater (heating means)
10 metal tube 12 non-fixed part 14 control panel (control means)
15 Cooling water circulator (cooling means)
15b Cooling pipe 15d Circulating means 30 Fixed part S1 Gap

Claims (3)

Between the fixing portion for contacting the outer peripheral surface on one end side of the metal tube and fixing the metal pipe and the outer peripheral surface on the other end side of the metal pipe provided continuously to the fixing portion and fixed to the fixing portion. A clamp type having a non-fixed portion that forms a gap over the circumferential direction,
A punch die provided so as to be press-fitted from the other end opening into the metal tube fixed to the clamp die,
A heating means capable of heating the punch die,
The punch die is pressed into the metal tube through the other end opening while heating the punch die to a temperature higher than room temperature and lower than the recrystallization temperature by the heating means. A pipe expanding device, which is configured to expand outwardly in a radial direction until it extends along a fixed portion to expand a pipe. The tube expanding device according to claim 1,
A tube expanding device comprising a cooling means capable of cooling the clamp die. The pipe expanding device according to claim 2,
The cooling means comprises a cooling pipe provided in a portion of the clamp type excluding the fixing portion, and a circulation means for circulating a cooling fluid in the cooling pipe,
The tube expanding device, wherein the fixing portion is made of a ceramic material.

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