TW202212102A - Die for forming irregular bellow - Google Patents

Abstract

The present invention discloses a die that enables a tube to be formed into an irregular bellow by a fixed die and a movable die. The movable die is able to be moved toward the fixed die such that an extrusion cavity having variable gap exists between the fixed and movable dies. During hydroforming process, a first curve is formed on the tube in a forming cavity of the movable die and a pre-curve is formed on the tube in the extrusion cavity. The fixed and movable dies are provided to compress the pre-curved into a second curve having a shape different from that of the first curve.

Description

Forming die for special-shaped bellows

The invention relates to a tube processing and forming die, in particular to a forming die for forming a special-shaped corrugation on a tube.

In the manufacturing industry of automobiles, locomotives, bicycles, sanitary equipment and machinery, the pipes are designed to have corrugated pipes due to the requirements of appearance or function (such as light weight, rigidity, shock absorption, etc.).

In order to form corrugations on the pipe, a hydroforming method is used to place a pipe into a mold, and after hydraulic oil is injected, the pipe is inflated and expanded to a cavity of the mold, so that the pipe is corrugated, However, when the shape of the corrugation of the pipe is more complicated due to requirements, for example, when the pipe is formed with corrugations of different shapes, the cavity design of the hydroforming mold and the bulging of the pipe (such as pipe thickness, ductility, etc.) factors, It will affect whether the pipe can form corrugations of different shapes in the hydroforming process, especially when the shape of the corrugation is quite different, it is easy to cause the pipe to be wrinkled, buckling and buckling during the hydroforming process. Bursting and other issues.

The main purpose of the present invention is to form a pipe material into a corrugated pipe with different corrugated shapes in a hydroforming process by using a molding die of a special-shaped corrugated pipe.

The present invention provides a forming die for a special-shaped corrugated pipe, which is used to form a pipe into a corrugated pipe with different corrugated shapes. The forming die includes a first die set and a second die set, and the first die set includes A first base, at least a first fixed mold and at least a first movable mold, the first base has a first body and a first accommodating groove, along a first axis, the first accommodating The accommodating groove is recessed in the first body, the first fixed mold is fixed on the first base, the first movable mold is movably disposed in the first accommodating groove, and along the first axial direction, the The first moving mold is selectively moved toward or away from the first fixed mold, so that there is a first extrusion molding cavity with a variable gap between the first moving mold and the first fixed mold. The first moving mold The mold has a first surface and at least one first groove recessed on the first surface, the first groove has a first molding cavity, the first molding cavity is used for accommodating the pipe, the first cavity is The two die sets move toward the first die set along a second axis intersecting the first axis, and the second die set includes a second base, at least a second fixed die and at least a second movable die, The second base has a second body and a second accommodating groove, along the first axial direction, the second accommodating groove is recessed in the second body, and the second fixing mold is fixed on the second a base, the second moving mold is movably disposed in the second accommodating groove, and along the first axial direction, the second moving mold is selectively moved toward or away from the second fixed mold, so that the first A second extrusion die cavity with a variable gap between the two movable dies and the second fixed die, the second movable die has a second surface and at least one second groove recessed on the second surface , the second surface faces the first surface of the first moving mold, the second groove has a second molding cavity, the second molding cavity is used to accommodate the pipe, in a hydroforming process, The first forming die cavity and the second forming die cavity are used to form a first corrugation on the pipe material, and the pipe material is formed in the first extrusion forming die cavity and the second extrusion forming die cavity with a Corrugations to be formed, when the first moving mold and the second moving mold move toward the first fixed mold and the second fixed mold along the first axial direction, the to-be-formed corrugations are moved by the first fixed mold, the second fixed mold The first movable die, the second fixed die and the second movable die are extruded to form a second corrugated pipe, and the shape of the second corrugated pipe is different from that of the first corrugated pipe.

The present invention provides a forming die for a special-shaped corrugated tube, which is used to form a pipe into a corrugated tube with different corrugated shapes. The forming die includes at least a fixed die and a movable die. The movable die selectively faces the fixed The mold moves so that there is an extrusion molding cavity with a variable gap between the movable mold and the fixed mold. The movable mold has a molding cavity for accommodating the pipe, and a hydroforming cavity is formed. In the manufacturing process, the forming die cavity is used to form a first pipe corrugation on the pipe material, and the pipe material is formed with a to-be-formed corrugation in the extrusion forming die cavity, and the fixed die and the moving die are used for the to-be-formed corrugation. The corrugation is extruded into a second pipe corrugation, and the shape of the second pipe corrugation is different from that of the first pipe corrugation.

The present invention utilizes the forming cavity of the moving die and the extrusion forming cavity located between the moving die and the fixed die to inflate and expand the pipe material to the forming die during the hydroforming process The first pipe corrugation and the corrugation to be formed are formed in the cavity and the cavity of the extrusion molding die, and the corrugation to be formed is extruded by the moving die and the fixed mold, so that the corrugation to be formed is extruded into the corrugation to be formed. The second pipe is corrugated, so that the pipe is formed into a corrugated pipe with special-shaped corrugations, which can avoid the wrinkling caused by the formation of corrugations of different shapes in the hydroforming process only by the cavity design of the hydroforming mold. ), Buckling and Bursting.

Please refer to FIGS. 1 to 5 , a special-shaped corrugated tube forming mold 10 for forming a pipe material O into a corrugated tube with different corrugated shapes. The forming mold 10 includes a first mold set 100 and a second mold Set 200, the pipe material O is disposed between the first die set 100 and the second die set 200, please refer to Figures 2 to 5, in this embodiment, two punches are used to block the two pipes of the pipe material O respectively The two punches are respectively a blocking punch 20 and a liquid supply punch 30. During a hydroforming process, a pipeline 31 of the liquid supply punch 30 is used to supply hydraulic oil (not shown in the figure). Filled in the pipe material O, the present embodiment does not limit the shape of the punch and the method of filling hydraulic oil.

Please refer to FIGS. 1 to 5 , the first mold set 100 includes a first base 110 , at least one first fixed mold 120 and at least one first movable mold 130 , the first base 110 has a first body 111 and a first accommodating groove 112, along a first axial direction X, the first accommodating groove 112 is recessed in the first body 111, in this embodiment, along a first axial direction X intersecting A second axis Y, the first fixed mold 120 is fixed on the first base 111, please refer to Figures 1, 4 and 6, in this embodiment, the first fixed mold 120 has a first limit part 121 and at least one first fixing part 122, the first fixing mold 120 is fixed to the first body 111 by the first fixing part 122, preferably, the first body 111 has at least one first slot 111a, The first fixed mold 120 is embedded in the first slot 111 a with the first fixed portion 122 , which can be replaced with another first fixed mold 120 according to process requirements.

Please refer to FIGS. 1, 4, 5 and 6, the first moving mold 130 is movably disposed in the first accommodating groove 112, and along the first axis X, the first moving mold 130 is selectively Move toward or away from the first fixed mold 120 to make a first extrusion molding cavity 140 with a variable gap between the first movable mold 130 and the first fixed mold 120 (please refer to FIGS. 5 and 6 ). ), in this embodiment, the first extrusion die cavity 140 is located between the first limiting portion 121 and the first moving die 130, please refer to Figures 1, 4, 6 and 7, preferably , the first mold set 100 further includes at least one first elastic member 150, please refer to FIG. 7, a first end 151 of the first elastic member 150 is used to abut against the first fixed mold 120, the first elastic member A second end 152 of the 150 is used to abut against the first moving mold 130 . In this embodiment, the first moving mold 130 has a first side surface 133 and at least one first container recessed on the first side surface 133 . The first side 133 faces the first fixed mold 120, the first elastic member 150 is disposed in the first accommodating hole 134, and the first end 151 of the first elastic member 150 protrudes out of the hole 134. The first side 133 .

Please refer to FIGS. 1 , 2 and 4. In this embodiment, the first base 110 has a first guide member 113, and along the first axis X, the first guide member 113 is disposed on the In the first accommodating groove 112, the first moving mold 130 has a guide groove 135, and the first moving mold 130 is movably combined with the first guide member 113 by the guide groove 135, and the first moving mold 130 is The guide piece 113 and the guide groove 135 can prevent the first movable mold 130 from moving in a biased manner. Preferably, the first fixed mold 120 has a recessed groove 123 for the first fixed mold 120 The groove 123 spans the first guide member 113 , and the first limiting portion 121 of the first fixed mold 120 is located above the first guide member 113 .

Please refer to FIGS. 1 to 6 , the first movable mold 130 has a first surface 131 and at least one first groove 132 recessed in the first surface 131 , and the first groove 132 has a first forming mold A cavity 132a, the first molding cavity 132a is used for accommodating the pipe material O. In this embodiment, the first fixed mold 120 has a first supporting groove 124, and the first supporting groove 124 is used for accommodating the pipe O. The pipe material O, and the pipe material O straddles the first fixed mold 120 .

Please refer to FIGS. 1 to 5 , the second die set 200 moves toward the first die set 100 along the second axis Y, and the pipe O is sandwiched between the first die set 100 and the second die set 200, the second mold set 200 includes a second base 210, at least a second fixed mold 220 and at least a second movable mold 230, the second base 210 has a second body 211 and a second The accommodating groove 212, along the first axial direction X, the second accommodating groove 212 is recessed in the second body 211, in this embodiment, along the second axial direction Y, the second fixed mold 220 is fixed on the second base 210, please refer to Figures 1, 4 and 9. In this embodiment, the second fixing mold 220 has a second limiting portion 221 and first at least one second fixing portion 222 , the second fixing mold 220 is fixed to the second body 211 by the second fixing portion 222, preferably, the second body 211 has at least one second slot 211a, and the second fixing portion 222 is embedded in the second body 211a. The two slots 211a can be replaced with another second fixed mold 220 according to the requirements of the process.

Please refer to Figures 1, 4, 5, 8 and 9, the second moving mold 230 is movably disposed in the second accommodating groove 212, and along the first axis X, the second moving mold 230 selects move toward or away from the second fixed mold 220, so that there is a second extrusion cavity 240 with a variable gap between the second movable mold 230 and the second fixed mold 220 (please refer to Sections 5 and 9). ), in this embodiment, the second extrusion die cavity 240 is located between the second limiting portion 221 and the second moving die 230, please refer to Figures 1, 4, 7, 8 and 9, Preferably, the second mold set 200 further includes at least one second elastic member 250, please refer to FIG. 7, a first end 251 of the second elastic member 250 is used to abut against the second fixed mold 220, the first end 251 of the second elastic member 250 A second end 252 of the two elastic members 250 is used to abut against the second moving mold 230 . In this embodiment, the second moving mold 230 has a second side surface 233 and at least one recessed side surface 233 . The second accommodating hole 234 , the second side surface 233 faces the second fixed mold 220 , the second elastic member 250 is disposed in the second accommodating hole 234 , and the first end 251 of the second elastic member 250 Protruding from the second side surface 233 .

Please refer to Figures 1, 2, 4 and 8, the second base 210 has a second guide member 213, along the first axis X, the second guide member 213 is disposed in the second accommodating In the groove 212, the second guide member 213 has a first limiting end portion 213a, the first limiting end portion 213a is exposed in the second accommodating groove 212, and the second moving mold 230 has a combining end portion 235, along the first axial direction X, the second moving mold 230 is movably combined with the first limiting end portion 213a of the second guide member 213 with the combining end portion 235, and along the second moving mold 230 Axial Y, the second base 210 drives the second movable mold 230 with the second guide member 213, and the second guide member 213 can prevent the second movable mold 230 from moving in a biased manner. In this embodiment, The second limiting portion 221 of the second fixed mold 220 is located below the second guide member 213 , and the second base 210 has an engaging groove 214 along the first axis X, the engaging groove 214 Recessed in the second accommodating groove 212, the second guide member 213 has a second limiting end portion 213b, the second limiting end portion 213b is movably combined with the engaging groove 214, along the second limiting end portion 213b Axial Y, the second base 210 drives the second guide 213 .

Please refer to FIGS. 1 , 4 and 8 , the second movable mold 230 has a second surface 231 and at least one second groove 232 recessed in the second surface 231 , and the second groove 232 has a second groove 232 . Forming cavities 232a, the second surface 231 faces the first surface 131 of the first moving die 130, the two forming cavities 232a are used for accommodating the pipe O, in this embodiment, the second fixed die 220 There is a second supporting groove 223, the second supporting groove 223 is used for accommodating the pipe material O, and the pipe material O spans the second fixed mold 220, along the second axis Y, the first The supporting groove 124 and the second supporting groove 223 are located on opposite sides of the pipe material O.

Please refer to FIGS. 5 and 7 , in this embodiment, the forming mold 10 includes a first mold base 300 , a second mold base 400 , at least one first gasket 500 and at least one second gasket 600 , The first mold base 300 has a first chamber 310, the first mold set 100 is disposed in the first chamber 310, the second mold base 400 has a second chamber 410, and the second mold set 200 is disposed in the first chamber 310 In the second chamber 410, the first gasket 500 is disposed between the first moving mold 130 and a side wall 311 of the first chamber 310, and the first moving mold 130 is located between the first elastic member 150 and the first moving mold 130. Between a spacer 500, the second spacer 600 is disposed between the second moving mold 230 and a side wall 411 of the second chamber 410, and the second moving mold 230 is located between the second elastic member 250 and the between the second spacers 600 .

Please refer to FIGS. 5 and 7 , the first movable mold 130 is pressed against the first gasket 500 by the elastic force of the first elastic member 150 , and the second movable mold is caused by the elastic force of the second elastic member 250 A Before the first moving mold 130 and the second moving mold 230 are actuated, the variable clearance of the first extrusion cavity 140 between the first moving mold 130 and the first fixed mold 120 is adjusted. and adjust the width of the variable gap of the second extrusion die cavity 240 between the second movable die 230 and the second fixed die 220 .

Please refer to FIGS. 2 , 3 and 5 , in this embodiment, the first moving mold 130 and the second moving mold 230 are pushed by the blocking punch 20 and/or the liquid supply punch 30 , and respectively Move toward the first fixed die 120 and the second fixed die 220 to reduce the width of the variable gap of the first extrusion cavity 140 and reduce the variable gap of the second extrusion cavity 240 width.

Please refer to FIGS. 10A to 10D , which are schematic diagrams of the operation of the present invention. First, please refer to FIG. 5 , the pipe material O is disposed between the first die set 100 and the second die set 200 , please refer to FIG. 5 10A, the pipe material O is accommodated in the first groove 132 of the first moving mold 130 and the second groove 232 of the second moving mold 230, and the pipe material O is located in the first fixed mold 120 Between the second fixed die 220, the second nozzles of the pipe material O are blocked by the blocking punch 20 and the liquid supply punch 30 respectively, and the first moving die 130 and the second moving die 230 are not blocked by the Before the blocking punch 20 and/or the liquid supply punch 30 is pushed, the first extrusion cavity 140 has a first gap L1, and the second extrusion cavity 240 has a second gap L2. In the embodiment, the width of the first gap L1 and the width of the second gap L2 are substantially the same, but not limited thereto.

Next, referring to FIG. 10B, a hydroforming process is performed. In this embodiment, a hydraulic oil is filled in the pipe material O through the liquid supply punch 30, so that a pipe wall O3 of the pipe material O is inflated and moved toward The first molding cavity 132a, the second molding cavity 232a, the first extrusion molding cavity 140 and the second extrusion molding cavity 240 expand, and the tube wall O3 is parallel to the first molding cavity 132a A first tube corrugation O1 is formed in the second molding cavity 232a, and a to-be-formed corrugation OX is formed in the first extrusion molding cavity 140 and the second extrusion molding cavity 240 on the tube wall O3.

Next, please refer to Figures 10C and 10D, along the first axis X, the blocking punch 20 and/or the liquid supply punch 30 is used to push the first moving die 130 and the second moving die 230 toward the The first fixed mold 120 and the second fixed mold 220 move to reduce the width of the first gap L1 and the width of the second gap L2, and the first fixed mold 120, the first movable mold 130, the first The two fixed molds 220 and the second moving mold 230 squeeze the corrugated OX to be formed, so that the corrugated OX to be formed is extruded into a second corrugated pipe O2, and the shape of the second corrugated pipe O2 is different from that of the first corrugated pipe O2. The shape of a tube corrugated O1.

The present invention uses the first molding cavity 132a and the second molding cavity 232a of the movable mold 130 to inflate and expand the pipe material O to the first molding cavity 132a and the second molding cavity 232a during the hydroforming process The cavity 232a is formed to form the first pipe corrugation O1, and the pipe material O is inflated and expanded to the The first extrusion molding cavity 140 and the second extrusion molding cavity 240 are used to form the to-be-formed corrugations OX, and the first fixed mold 120 , the first movable mold 130 , the second fixed mold The die 220 and the second moving die 230 extrude the corrugated OX to be formed into the second corrugated pipe O2, so that the pipe material O is formed into a corrugated pipe with irregular corrugations.

The protection scope of the present invention shall be determined by the scope of the appended patent application. Any changes and modifications made by anyone who is familiar with the art without departing from the spirit and scope of the present invention shall fall within the protection scope of the present invention. .

10: Forming mold 20: Blocking the punch 30: Liquid supply punch 31: Pipeline 100: The first die set 110: The first base 111: The first body 111a: first slot 112: The first accommodating slot 113: The first guide 120: The first fixed mold 121: The first limit part 122: The first fixed part 123: Make way for grooves 124: First support groove 130: The first mobile mold 131: First Surface 132: First groove 132a: The first molding cavity 133: The first side 134: The first accommodating hole 135: Guide groove 140: The first extrusion die cavity 150: First elastic piece 151: First End 152: Second End 200: The second die set 210: Second Pedestal 211: The second body 211a: Second slot 212: Second accommodating slot 213: Second guide 213a: The first limit end 213b: The second limit end 214: Engagement slot 220: Second fixed mold 221: The second limit part 222:Second fixed part 223: Second support groove 230: Second Mobile Die 231: Second Surface 232: Second groove 232a: The second molding cavity 233: Second side 234: Second accommodating hole 235: Combined ends 240: The second extrusion die cavity 250: Second elastic piece 251: First End 252: Second End 300: The first mold base 310: First Cabin 311: Sidewall 400: The second die base 410: Second cabin 411: Sidewall 500: First gasket 600: Second gasket L1: first gap L1: Second gap O: pipe O1: The first tube corrugated O2: The second tube corrugated O3: tube wall OX: Corrugated to be formed X: the first axis Y: the second axis

Figure 1: An exploded perspective view of the first die set and the second die set of the present invention. Figure 2: An exploded perspective view of the first die set and the second die set of the present invention. Fig. 3 is a perspective view of the first die set and the second die set of the present invention. Fig. 4 is an exploded perspective view of the molding die of the special-shaped corrugated pipe of the present invention. Fig. 5 is a cross-sectional view of the molding die of the special-shaped corrugated tube of the present invention. Figure 6: Top view of the first die set of the present invention. Fig. 7 is a cross-sectional view of the molding die of the special-shaped corrugated tube of the present invention. Figure 8: An exploded perspective view of the second mold set of the present invention from another perspective. . Figure 9: Bottom view of the second die set of the present invention. Figures 10A to 10D: Schematic diagrams of the operation of the forming die for the special-shaped corrugated pipe of the present invention.

10: Forming mold

100: The first die set

110: The first base

111: The first body

111a: first slot

112: The first accommodating slot

113: The first guide

120: The first fixed mold

122: The first fixed part

124: First support groove

130: The first mobile mold

131: First Surface

132: First groove

132a: The first molding cavity

200: The second die set

210: Second Pedestal

211: The second body

211a: Second slot

212: Second accommodating slot

213: Second guide

213a: The first limit end

213b: The second limit end

220: Second fixed mold

222:Second fixed part

230: Second Mobile Die

231: Second Surface

232: Second groove

232a: The second molding cavity

500: First gasket

600: Second gasket

O: pipe

X: the first axis

Y: the second axis

Claims (14)

A special-shaped corrugated pipe forming mold, which is used to form a pipe into a corrugated pipe with different corrugated shapes, and the forming mold comprises: A first die set, comprising: a first base having a first body and a first accommodating groove, the first accommodating groove is recessed in the first body along a first axial direction; at least one first fixed mold fixed on the first base; and At least one first moving mold is movably disposed in the first accommodating groove, and along the first axial direction, the first moving mold is selectively moved toward or away from the first fixed mold, so that the first A first extrusion molding cavity with a variable gap between the movable mold and the first fixed mold, the first movable mold has a first surface and at least one first groove recessed on the first surface , the first groove has a first molding cavity, and the first molding cavity is used for accommodating the pipe; and A second die set moves toward the first die set along a second axis intersecting with the first axis, and the second die set includes: a second base having a second body and a second accommodating groove, the second accommodating groove is recessed in the second body along the first axial direction; at least one second fixed mold, fixed on the second base; and At least one second movable mold is movably disposed in the second accommodating groove, and along the first axial direction, the second movable mold selectively moves toward or away from the second fixed mold, so that the second There is a second extrusion molding cavity with a variable gap between the movable mold and the second fixed mold, the second movable mold has a second surface and at least one second groove recessed on the second surface, The second surface faces the first surface of the first moving mold, the second groove has a second molding cavity, and the second molding cavity is used for accommodating the pipe. In a hydroforming process, the The first forming die cavity and the second forming die cavity are used to form a first pipe corrugation on the pipe material, and the pipe material is formed in the first extrusion forming die cavity and the second extrusion forming die cavity with a waiting area to be formed. Forming corrugations, when the first moving mold and the second moving mold move along the first axial direction toward the first fixed mold and the second fixed mold, the to-be-formed corrugations are moved by the first fixed mold, the second fixed mold The two fixed molds, the first moving mold and the second moving mold are extruded to form a second corrugated pipe, and the shape of the second corrugated pipe is different from that of the first corrugated pipe. The forming mold of the special-shaped corrugated pipe according to claim 1, wherein the first fixed mold has a first supporting groove, and the first supporting groove is used for accommodating the pipe. The forming die for a special-shaped corrugated tube as claimed in claim 1, wherein the second fixed die has a second limiting portion and first at least one second fixing portion, and the second extrusion molding cavity is located at the second limiting portion Between the second movable mold and the second fixed mold, the second fixed mold is fixed to the second body by the second fixed portion. The forming mold of the special-shaped corrugated pipe according to claim 3, wherein the second body has at least one second slot, and the second fixing portion is embedded in the second slot. The forming die for a special-shaped corrugated pipe according to claim 1, wherein the second base has a second guide member, and along the first axial direction, the second guide member is disposed in the second accommodating groove, The second guide member has a first limiting end portion, the first limiting end portion is exposed in the second accommodating groove, and the second moving mold has a combining end portion along the first axial direction, The second movable mold is movably coupled to the first limiting end of the second guide member with the coupling end, and along the second axial direction, the second base and the second guide member Drive the second moving mold. The forming die for a special-shaped corrugated tube as claimed in claim 5, wherein the second base has an engaging groove, and along the first axial direction, the engaging groove is recessed in the second accommodating groove, and the second guiding member A second limiting end portion is provided, the second limiting end portion is movably combined with the engaging groove, and along the second axial direction, the second base drives the second guiding piece. The forming die for a special-shaped corrugated pipe according to claim 1, wherein the second base has a second guide member, and along the first axial direction, the second guide member is disposed in the second accommodating groove, A second limiting portion of the second fixed mold is located below the second guide member. The forming mold for the special-shaped corrugated pipe according to claim 2, wherein the second fixed mold has a second supporting groove, the second supporting groove is used for accommodating the pipe, and along the second axial direction, the first supporting groove A supporting groove and the second supporting groove are located on opposite sides of the pipe. The forming mold for a special-shaped corrugated tube as claimed in claim 1, wherein the second mold set further comprises at least one second elastic member, a first end of the second elastic member is used to abut against the second fixed mold, and the second elastic member A second end of the piece is used to abut against the second moving mold. The forming mold for a special-shaped corrugated tube as claimed in claim 9, wherein the second movable mold has a second side surface and at least one second accommodating hole recessed on the second side surface, and the second side surface faces the second fixed mold , the second elastic piece is arranged in the second accommodating hole, and the first end of the second elastic piece protrudes from the second side surface. The forming mold for the special-shaped corrugated pipe as claimed in claim 9, further comprising a second mold base and at least one second gasket, the second mold base has a second chamber, and the second mold set is disposed in the second chamber wherein, the second gasket is disposed between the second moving mold and a side wall of the second chamber, and the second moving mold is located between the second elastic member and the second gasket. A special-shaped corrugated pipe forming mold, which is used to form a pipe into a corrugated pipe with different corrugated shapes, and the forming mold comprises: at least one stationary mold; and A movable mold is selectively moved toward the fixed mold, so that there is an extrusion molding cavity with a variable gap between the movable mold and the fixed mold, the movable mold has a molding cavity, and the molding cavity is In order to accommodate the pipe material, in a hydroforming process, the forming die cavity is used to form a first pipe corrugation on the pipe material, and make the pipe material form a corrugation to be formed in the extrusion molding die cavity, and the fixed mold and the moving die is used for extruding the to-be-formed corrugation into a second pipe corrugation, and the shape of the second pipe corrugation is different from that of the first pipe corrugation. As claimed in claim 12, the molding die for a special-shaped bellows further comprises at least one elastic piece, a first end of the elastic piece is used for contacting the first fixed mold, and a second end of the first elastic piece is used for contacting the first fixed mold The mobile mold. As claimed in claim 13, the forming mold for the special-shaped bellows further comprises a mold base and at least one gasket, the mold base has a compartment, the base is arranged in the compartment, and the gasket is arranged between the moving mold and the spacer. between one side wall of the chamber, and the moving mold is located between the elastic piece and the gasket.

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