CN113290101A - Three-step hydraulic precise forming die and method for rectangular corrugated pipe - Google Patents
Three-step hydraulic precise forming die and method for rectangular corrugated pipe Download PDFInfo
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- CN113290101A CN113290101A CN202110451347.8A CN202110451347A CN113290101A CN 113290101 A CN113290101 A CN 113290101A CN 202110451347 A CN202110451347 A CN 202110451347A CN 113290101 A CN113290101 A CN 113290101A
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- mandrel
- tube blank
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D15/00—Corrugating tubes
- B21D15/04—Corrugating tubes transversely, e.g. helically
- B21D15/06—Corrugating tubes transversely, e.g. helically annularly
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
- B21C37/00—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
- B21C37/06—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape of tubes or metal hoses; Combined procedures for making tubes, e.g. for making multi-wall tubes
- B21C37/15—Making tubes of special shape; Making tube fittings
- B21C37/156—Making tubes with wall irregularities
- B21C37/158—Protrusions, e.g. dimples
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D15/00—Corrugating tubes
- B21D15/04—Corrugating tubes transversely, e.g. helically
- B21D15/10—Corrugating tubes transversely, e.g. helically by applying fluid pressure
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- Shaping Metal By Deep-Drawing, Or The Like (AREA)
Abstract
A lower mandrel and a lower end cover are placed on the central surface of a lower guide plate, a rectangular tube blank is sleeved on a lower mandrel and lower end cover assembly, a lower end die is sleeved on the outer side of the lower end of the rectangular tube blank, the lower end die is in contact with the lower end cover, positioning limiting dies and middle dies are alternately arranged above the lower end die and the outer side of the rectangular tube blank, the uppermost layer and the lowermost layer are positioning limiting dies, an upper end die is arranged above the uppermost layer positioning limiting die, an upper end die is sleeved on the outer side of the upper end of the rectangular tube blank, an upper end cover and an upper mandrel are arranged on the inner side of the upper end of the rectangular tube blank, an upper guide plate is arranged above the upper end cover and the upper mandrel, and guide posts penetrate through guide post mounting holes in the lower guide plate and guide post mounting holes in an upper guide plate upper shaft sleeve. The invention has the advantages of high precision of the finished piece, simple forming process, high production efficiency and low manufacturing cost.
Description
Technical Field
The invention relates to the technical field of hydraulic forming of metal corrugated pipes with special-shaped circumferential outline, in particular to a three-step hydraulic precise forming die and a three-step hydraulic precise forming method for rectangular corrugated pipes.
Background
The traditional circular metal corrugated pipe is a revolving body part with a circular circumferential outline and cross section structural forms of U-shaped, S-shaped, omega-shaped and the like, is widely applied to the fields of aerospace, ships, nuclear energy, electric power, petrifaction, buildings and the like as an elastic element, plays the functions of flexible compensation, sealing, vibration reduction and the like, and is one of important parts of a pipeline connecting system, a sealing system and a vibration reduction system. In recent years, with the continuous expansion of the application field of the metal corrugated pipe, the circumferential outline of the metal corrugated pipe needs to be in a rectangular shape, a runway shape and other special shapes in the face of some special working conditions.
The common forming methods of the circular metal corrugated pipe comprise mechanical bulging, roll forming, hydraulic bulging and the like, wherein the hydraulic bulging process has the advantages of high forming efficiency, good mechanical property of a finished piece, high precision, short period, low cost, near-net forming and the like, and is widely applied to the precise plastic forming of the circular metal corrugated pipe at home and abroad.
The hydraulic bulging process (two-step method) of the round metal corrugated pipe comprises two steps of wave generation and forming, and because the internal pressure and the deformation difficulty degree of each part on the same cross section of the round pipe along the radial direction are the same in the forming process, the round metal corrugated pipe with high precision can be manufactured by adopting the two-step method. The rectangular metal corrugated pipe has obvious change of circumferential outline (transition round corners and straight line sections), when the rectangular metal corrugated pipe is formed by adopting a two-step method, the deformation resistance of materials at four transition round corners of the rectangular pipe blank is greater than that of the straight line sections, and if the rectangular metal corrugated pipe is formed by using the forming internal pressure at the transition round corners, the wave height of the straight line sections is far greater than a target value; when the molding is performed at the molding internal pressure of the straight line segment, the wave height at the transition round angle hardly reaches the target value. Therefore, the conventional hydraulic bulging process (two-step process) for circular metal corrugated pipes is no longer suitable for precise plastic forming of special-shaped metal corrugated pipes represented by rectangular metal corrugated pipes.
Disclosure of Invention
In order to solve the technical problems, the invention aims to provide a three-step hydraulic precise forming die and a three-step hydraulic precise forming method for a rectangular corrugated pipe, and the hydraulic precise plastic forming process problem of special-shaped metal corrugations represented by the rectangular metal corrugated pipe is solved under the condition that the forming process is not changed.
In order to achieve the purpose, the invention adopts the technical scheme that:
a three-step hydraulic precise forming die for rectangular corrugated pipes comprises a lower guide plate 16 flatly placed on a hydraulic machine platform, wherein a lower mandrel 15 and a lower end cover 4 are placed on the central surface of the lower guide plate 16, a rectangular pipe blank 10 is sleeved on an assembly body formed by the lower mandrel 15 and the lower end cover 4, a lower end die 13 is sleeved on the outer side of the lower end of the rectangular pipe blank 10, the lower end die 13 is in contact with the lower end cover 4, positioning shape limiting dies and middle dies are alternately arranged above the lower end die 13 and outside the rectangular pipe blank 10, the uppermost layer and the lowermost layer are positioning shape limiting dies, an upper end die 5 is arranged above the uppermost layer of the die positioning shape limiting dies, the upper end die 5 is sleeved on the outer side of the upper end of the rectangular pipe blank 10, an upper end cover 4 and an upper mandrel 1 are arranged on the inner side of the upper end of the rectangular pipe blank 10, the upper mandrel 1 is the same as the axis position of the lower mandrel 15, and an upper guide plate 3 is arranged above the upper end cover 4 and the upper mandrel 1, the surface of the upper guide plate 3 is provided with four guide post shaft sleeve mounting holes, the surface of the lower guide plate 16 is provided with four guide post mounting holes, the guide post shaft sleeve mounting holes on the upper guide plate 3 and the guide post mounting holes on the lower guide plate 16 are arranged at equal intervals around the rectangular tube blank 10, and the guide posts 7 penetrate through the guide post mounting holes on the lower guide plate 16 and the guide post mounting holes of the upper shaft sleeve 6 of the upper guide plate 3.
The upper mandrel 1 comprises a mandrel 1-1 and a rectangular bottom plate 1-2, and the rectangular bottom plate 1-2 is of a stepped structure and is positioned at the bottom of the upper mandrel 1; the mandrel 1-1 is of a cylindrical structure, threads matched with the fastening nut 2 are arranged on the mandrel 1-1, and the mandrel 1-1 is positioned at the centroid above the rectangular bottom plate 1-2; the fastening nut 2 is used for connecting and fixing the upper mandrel 1, the upper end cover 4, the lower mandrel 15 and the lower end cover 4;
the lower mandrel 15 comprises a rectangular bottom plate and a mandrel, the rectangular bottom plate is of a stepped structure and is positioned at the bottom, the mandrel is of a cylindrical structure, the diameter of the lower end of the cylindrical structure is larger than that of the upper end of the cylindrical structure, the cylindrical structure is positioned above the rectangular bottom plate, threads are arranged on the upper end and the lower end of the mandrel, the upper end thread 15-2 of the mandrel is used for connecting a liquid conduit of a hydraulic pump, and the lower end thread 15-3 is matched with the fastening nut 2; a circular through hole 15-1 is formed in the center of the mandrel of the lower mandrel 15 and penetrates through the mandrel and the rectangular bottom plate; the threaded end of the lower mandrel 15 is horizontally placed downwards and is arranged above the lower end cover 4, and the mandrel passes through a mandrel shaft hole 4-1 on the lower end cover 4 and is fixed by a fastening nut 2.
The whole shape of the upper guide plate 3 is a round thick plate, 4 guide post shaft sleeve mounting holes 3-1 and an upper core shaft 1 mandrel placing hole 3-2 are arranged on the upper guide plate 3, the 4 guide post shaft sleeve mounting holes 3-1 are positioned at the edge of the round thick plate, the circle center position of the guide post shaft sleeve mounting hole 3-1 is the same as that of the guide post mounting hole 16-1 on the lower guide plate 16, and the radius is the same as that of the cylindrical surface 6-2 of the guide post shaft sleeve 6 and used for mounting the guide post shaft sleeve 6.
The whole shape of the lower guide plate 16 is a round thick plate, 4 guide post mounting holes 16-1 and a lower mandrel 15 mandrel placing hole are formed in the lower guide plate 16, the 4 guide post mounting holes 16-1 are located at the edge of the round thick plate, the radius of the guide post mounting holes 16-1 is equal to that of the guide post 7, and a gap is formed between the edge of the guide post mounting hole 16-1 and the edge of the positioning limiting die outer ring 9.
The size and the structure of the upper end cover and the lower end cover are completely the same, the end covers 4 are the upper end cover 4 and the lower end cover 4, the end covers 4 are in a circular thick plate-shaped structure, and the centroid of each end cover 4 is provided with an upper mandrel 1 and a lower mandrel 15 mounting hole 4-1; the end face of the end cover 4 is provided with a rectangular annular boss 4-2, the shape of the outer side of the cross section of the rectangular annular boss 4-2 is the same as that of the inner side of the cross section of the rectangular tube blank 10, and the size of the outer side of the cross section of the rectangular annular boss 4-2 is smaller than that of the inner side of the cross section of the rectangular tube blank 10.
The upper end die piece 5 is of a round thick plate structure with steps on the inner side and the outer side, and the cross section is of a step shape; a rectangular through hole 5-2 is formed in the middle of the upper die plate 5, and the outline shape and the size of the rectangular through hole 5-2 are the same as those of the outer side of the cross section of the rectangular tube blank 10; a step-shaped structure is arranged at the junction of the large end plane of the upper end template 5 and the rectangular through hole 5-2, the width of the step 5-3 is equal to the ripple height of the rectangular corrugated pipe in target size, the height of the step 5-3 is equal to the ripple thickness of the rectangular corrugated pipe in target size, a round chamfer 5-1 is arranged at the junction of the horizontal plane of the step 5-3 and the rectangular through hole, and the radius of the round chamfer 5-1 is equal to the radius of the trough of the rectangular corrugated pipe in target size;
the lower end die 13 is of a round thick plate-shaped structure with a round boss, the end of the round boss is the upper end, the round thick plate at the bottom is the lower end, a rectangular through hole is arranged in the middle of the lower end die 13, and the outline shape and the size of the rectangular through hole are the same as those of the outer side of the cross section of the rectangular tube blank 10; a round chamfer 13-1 is arranged at the junction of the rectangular through hole and the lower end surface of the lower end die piece 13, and the radius of the round chamfer 13-1 is determined according to the radius of a wave trough of the target size of the rectangular corrugated pipe.
The guide post shaft sleeve 6 is of a circular tubular structure with a circular boss, and a through hole with the same diameter as that of the guide post 7 is formed in the center of the guide post shaft sleeve 6; the bottom of the guide post shaft sleeve 6 is provided with a circular boss with a slightly larger diameter, the diameter of the circular boss is larger than that of the outer surface 6-2 of the circular tube, and the diameter of the outer surface 6-2 of the circular tube is the same as that of a guide post shaft sleeve mounting hole 3-1 on the upper guide plate 3; the guide post 7 is of a cylindrical structure, the diameter of the guide post is the same as that of a guide post mounting hole 16-1 on the lower guide plate 16, and positioning and guiding functions are achieved.
The positioning shape limiting die comprises an inner die 8 of the positioning shape limiting die and an outer ring 9 of the positioning shape limiting die, the inner die 8 of the positioning shape limiting die adopts a half split die structure, the whole appearance of the inner die 8 of the positioning shape limiting die is a half ring with bosses with different shapes on the inner side and the outer side, and a semicircular boss with a step-shaped section is arranged on the outer side of the inner die 8 of the positioning shape limiting die; three bosses are arranged on the inner side of the die 8 in the positioning and limiting die, an arc surface 8-1 is arranged on one side of each boss close to the rectangular tube blank 10, and a space 8-2 between each boss is obtained by 1/4 circular cutting; the positioning shape limiting die sheet outer ring 9 is a circular ring with a boss 9-1 on the inner side, and the whole thickness of the positioning shape limiting die sheet outer ring 9 is smaller than that of the die sheet 8 in the positioning shape limiting die sheet and is used for fixing the die sheet 8 in the positioning shape limiting die sheet.
The cross section of the rectangular tube blank 10 is rectangular with four corners being round corners, and is obtained by bending and welding plates.
The middle die comprises a middle die outer ring 11 and a middle die inner die 12, the middle die outer ring 11 is a circular ring with a boss 11-1 on the inner side, and the whole thickness of the middle die outer ring 11 is smaller than that of the middle die inner die 12 so as to fix the middle die inner die 12; the inner die piece 12 of the middle die adopts a half split die structure, the whole appearance is a flat plate with the outer side outline of 1/2 circles and the inner side outline of 1/2 rectangular notches, and a boss matched with the outer ring 11 of the middle die piece is arranged on the outer side of the inner die piece 12 of the middle die piece; the inner side of the die 12 in the middle die is provided with a boss 12-1 with a rectangular periphery, the thickness of the boss 12-1 is equal to the diameter of a wave trough of a target size of the rectangular corrugated pipe, and the thickness of a blank part 12-2 above the boss 12-1 is equal to the diameter of a wave crest of the target size of the rectangular corrugated pipe.
And the upper mandrel 1 and the lower mandrel 15 are provided with rubber sealing rings 14, and the rubber sealing rings 14 are of annular structures with circular cross sections and are used for sealing the upper end and the lower end of the rectangular tube blank 10.
The secondary wave-starting positioning block 17 is of a cuboid structure, the height of the secondary wave-starting positioning block is equal to the distance between the dies during secondary wave-starting, and the secondary wave-starting positioning block is used for positioning the dies.
A three-step hydraulic precise forming method for a rectangular corrugated pipe comprises the following steps:
the method comprises the following steps: manufacturing a rectangular tube blank 10;
the manufacturing of the rectangular tube blank 10 comprises the following three steps of material preparation, bending and welding: cutting an original strip into a rectangular strip with a certain length and width, determining the arc center position of a rectangular transition fillet on the long side of the rectangular strip, pressing 10 transition fillets of a rectangular tube blank by bending equipment, and finally obtaining the rectangular tube blank 10 with only one welding line by welding;
step two: assembling a mould;
sleeving a rubber sealing ring 14 on a lower mandrel 15, and connecting and fixedly assembling a lower end cover 4 and the lower mandrel 15 together through a fastening nut 2; the lower guide plate 16 is flatly placed on a platform of the hydraulic machine, after a liquid guide pipe of the hydraulic pump passes through a mandrel placing hole of a lower mandrel 15 on the lower guide plate 16 and is connected with the lower mandrel 15, the lower end cover 4 and an assembly body of the lower mandrel 15 are placed above the lower guide plate 16, and the mandrel of the lower mandrel 15 is placed downwards; marking the upper end and the lower end of a rectangular tube blank 10, sleeving a lower end matrix 13 outside the lower end of the rectangular tube blank 10, aligning the end surface of a circular boss end of the lower end matrix 13 with the edge of the lower end of the rectangular tube blank 10, and assembling the lower end matrix 13 and the rectangular tube blank 10 above a lower end cover 4 and a lower mandrel 15 assembly; two matched positioning shape limiting die inner dies 8 are placed above the lower end die 13 and spliced together, and the positioning shape limiting die inner dies 8 are fixed by the positioning shape limiting die outer rings 9; two matched inner die sheets 12 of the middle die sheet are placed above the positioning shape limiting die sheet and spliced together, and the inner die sheets 12 of the middle die sheet are fixed by an outer ring 11 of the middle die sheet; sequentially assembling positioning shape limiting dies and intermediate dies, wherein the positioning shape limiting dies and the intermediate dies are alternately arranged, and the number of the positioning shape limiting dies and the intermediate dies is determined by the wave number of the rectangular corrugated pipe; after the last positioning limiting die piece is assembled, the upper end die piece 5 is sleeved at the upper end of the rectangular tube blank 10; starting a hydraulic pump, and closing the hydraulic pump when the internal cavity of the rectangular tube blank 10 is filled with liquid; the rubber sealing ring 14 is sleeved on the upper mandrel 1, the upper end cover 4 and the upper mandrel 1 are connected and fixedly assembled together through the fastening nut 2, and the upper end cover 4 and the upper mandrel 1 assembly body are assembled above the rectangular tube blank 10; finally, four guide posts 7 are inserted, and the upper guide plate 3 provided with the shaft sleeve 6 is arranged on the top through the four guide posts 7;
step three: primary wave starting;
pressure P in the primary wave1The calculation formula of (a) is as follows:
in the formula, t is the wall thickness (mm) of the rectangular tube blank;
σb-material tensile strength (MPa);
Dtransition fillet-the diameter (mm) of the transition fillets of the rectangular tube blank;
the pressure head of the press is downward, the hydraulic pump is started after the upper guide plate 3 is tightly pressed, so that liquid continuously flows to the inner cavity of the rectangular tube blank 10 through the liquid guide pipe of the hydraulic pump, and when the internal pressure reaches P1When the pressure is higher than the preset pressure, the hydraulic pump is closed, and the internal pressure is reduced to 0 MPa;
step four: secondary wave generation;
moving a press head upwards, taking down the upper guide plate 3, pulling out the guide post 7, sequentially disassembling all the positioning shape limiting die sheets outer rings 9 and the positioning shape limiting die sheets inner die sheets 8, and simultaneously placing the secondary wave-generating positioning blocks 17 between the die sheets for positioning;
pressure P in secondary wave2The calculation formula of (a) is as follows:
in the formula, t is the wall thickness (mm) of the rectangular tube blank;
σb-material tensile strength (MPa);
l is the length (mm) of the rectangular cross section of the rectangular tube blank; (including transition fillets)
W is the width (mm) of the rectangular cross section of the rectangular tube blank; (including transition fillets)
Installing the guide post 7 and the upper guide plate 3, enabling a pressure head of the press to be downward, starting the hydraulic pump after the upper guide plate 3 is pressed, and enabling the internal pressure to reach P2When the pressure is higher than the preset pressure, the hydraulic pump is closed, and the internal pressure is reduced to 0 MPa;
step five: hydroforming;
moving the pressure head of the press upwards, and taking down all the secondary wave-starting positioning blocks 17; the pressure head of the press moves downwards to apply a certain pressure to the upper guide plate 3; the hydraulic pump is started and the hydraulic pump is started,when the internal pressure reaches P2When the mold piece is completely closed, the pressure head of the press continues to move downwards;
step six: taking out the workpiece;
and (3) closing the hydraulic pump, moving a pressure head of the press upwards, sequentially taking down the upper guide plate 3, the guide pillar 7, the upper end cover 4, the upper core shaft 1 assembly body, the upper end matrix 5, the middle matrix and the lower end matrix 13, and taking out the rectangular metal corrugated pipe workpiece.
The forming method can be used for accurately forming the rectangular metal corrugated pipe and is also suitable for accurately forming the special-shaped metal corrugated pipe with different structures at different positions of the circumferential profile, such as a runway shape and the like;
the forming method can be used for manufacturing the rectangular metal corrugated pipe with 1 layer, 2 layers and multiple layers; when the rectangular metal corrugated pipes with different layers are formed, rectangular pipe blanks with corresponding layers can be prepared according to the first step, and the rest steps are the same;
the forming method can be used for precisely forming the metal corrugated pipe with the special-shaped structure, such as a rectangular corrugated pipe with a C-shaped, V-shaped, U-shaped, W-shaped and omega-shaped cross section, a runway-shaped corrugated pipe and the like, but not limited to the special-shaped structure; when the metal corrugated pipes with special-shaped structures such as rectangles, racetrack shapes and the like with different waveform cross sections are formed, the forming method is unchanged, and the forming die is correspondingly modified according to the structure and the size of a workpiece.
The invention has the beneficial effects that:
1. by adopting a three-step hydraulic precise forming method and a three-step hydraulic precise forming die for the rectangular corrugated pipe, the precise rectangular metal corrugated pipe with uniform and precise wave height and wave shape at the transition round corner and the straight line section can be manufactured, and the manufactured part has good performance, simple forming process, high production efficiency and low manufacturing cost;
2. the difficult problem of poor forming precision of the special-shaped metal corrugated pipe with the rectangular and runway-shaped circumferential outline is effectively solved;
3. the method has wide application range, and can be used for accurately forming the metal corrugated pipes with different sizes, different materials, different waveform cross sections, different layers and different circumferential profiles;
drawings
FIG. 1 is a half sectional view of a general assembly drawing of the mold.
FIG. 2 is a view of the lower guide plate, end cap and lower mandrel assembly.
FIG. 3 is an assembly view of the lower guide plate, end caps, lower mandrel and lower end form.
FIG. 4 is an assembly view of a lower guide plate, end caps, a lower mandrel, a lower end form, a tube blank, an intermediate die and a positioning limiting die.
Figure 5 is a schematic view of an intermediate die and a positioning limit die assembly.
Fig. 6 is an isometric view of the upper mandrel.
Fig. 7 is a cross-sectional view of the upper mandrel.
FIG. 8 is an isometric view of the upper and lower mandrel clinch nuts.
Fig. 9 is an isometric view of the upper guide plate.
Figure 10 is an isometric view of the end cap.
Fig. 11 is a cross-sectional view of the end cap.
Figure 12 is an upper die isometric view.
Figure 13 is an upper die cross-sectional view.
Fig. 14 is an isometric view of the guide post bushing.
Fig. 15 is a cross-sectional view of the guide post boss.
Figure 16 is an isometric view of the guide post.
Figure 17 is an isometric view of a die in a positioning limit die.
Figure 18 is a front view of a die in a position limiting module.
Figure 19 is an isometric view of an outer ring of a positioning limiting die.
Figure 20 is an outer ring cross-sectional view of a positioning limiting die.
Fig. 21 is an isometric view of a rectangular tube blank.
Figure 22 is an isometric view of an intermediate die outer ring.
Figure 23 is a cross-sectional view of an outer ring of an intermediate die.
Figure 24 is an isometric view of a die in an intermediate die.
Figure 25 is a front view of a die in an intermediate die.
Figure 26 is a lower die isometric view.
Figure 27 is a lower die cross-sectional view.
FIG. 28 is an isometric view of a rubber seal ring.
Fig. 29 is a lower isometric view.
Fig. 30 is a cross-sectional view of the lower mandrel.
Fig. 31 is a bottom guide isometric view.
FIG. 32 is an isometric view of a secondary lift spacer.
FIG. 33 is a graphical representation comparing two-step and three-step hydroforming results.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings.
As shown in fig. 1: a three-step hydraulic precise forming die for a rectangular corrugated pipe comprises: 1, tight nut 2, upper guide plate 3, end cover 4, upper end diaphragm 5, axle sleeve 6, guide pillar 7, the interior diaphragm 8 of the shape limit diaphragm in location, the shape limit diaphragm outer loop 9 of location, rectangular pipe 10, middle diaphragm outer loop 11, the interior diaphragm 12 of middle diaphragm, lower extreme diaphragm 13, rubber seal 14, lower mandrel 15, lower guide plate 16, secondary positioning piece 17 that ripples, its characterized in that:
as shown in fig. 1 to 5: a lower guide plate 16 is horizontally placed on a hydraulic press platform, a rubber seal ring 14 is sleeved on a lower mandrel 15, a lower end cover 4 and a lower mandrel 15 which are connected and fixedly assembled together through a fastening nut 2 are placed on the lower guide plate 16, the inner side of the lower end of a rectangular tube blank 10 is sleeved on an assembly body of the lower end cover 4 and the lower mandrel 15, a lower end die 13 is sleeved on the outer side of the lower end of the rectangular tube blank 10 and is tightly attached to the lower mandrel 15, a positioning limiting die (comprising an inner positioning limiting die 8 and an outer positioning limiting die ring 9) is arranged above the lower end die 13, an intermediate die (an outer intermediate die ring 11 and an inner intermediate die 12) is arranged above the positioning limiting die (8 and 9), positioning limiting dies (8 and 9) and intermediate dies (11 and 12) are alternately arranged on the outer side of the rectangular tube blank 10, an upper end die sheet 5 is arranged above the last positioning limiting die sheet (8, 9) and sleeved on the outer side of the upper end of a rectangular tube blank 10, a rubber sealing ring 14 is sleeved on an upper core shaft 1, an upper end cover 4 and the upper core shaft 1 which are connected and fixedly assembled together through a fastening nut 2 are placed above the upper end die sheet 5 and sleeved on the inner side of the upper end of the rectangular tube blank 10, four guide posts 7 are vertically placed through guide post holes in a lower guide plate 16, a shaft sleeve 6 is installed on a shaft sleeve hole of the upper guide plate 3, the upper guide plate 3 on which the shaft sleeve 6 is installed is horizontally placed above the upper end cover 4, and the four guide posts 7 penetrate through the guide post holes of the shaft sleeve 6.
As shown in fig. 6 and 7: the upper mandrel 1 comprises a mandrel 1-1 and a rectangular bottom plate 1-2, and the rectangular bottom plate 1-2 is of a stepped structure and is positioned at the bottom of the upper mandrel 1; the mandrel 1-1 is of a cylindrical structure and is provided with threads matched with the fastening nut 2, and the mandrel 1-1 is positioned at the centroid above the rectangular bottom plate 1-2; during assembly, the end of the mandrel 1-1 of the upper mandrel 1 is horizontally placed upwards and is arranged below the upper end cover 4; the mandrel 1-1 of the upper mandrel 1 passes through a mandrel shaft hole 4-1 on the upper end cover 4 and is fixed by a fastening nut 2.
As shown in fig. 8: the fastening nut 2 is a standard nut, and is determined according to the actual sizes of the upper mandrel 1 and the lower mandrel 15, and the fastening nut 2 plays a role in connection and fixation when the upper mandrel 1 and the upper end cover 4 are assembled and the lower mandrel 15 and the lower end cover 4 are assembled.
As shown in fig. 9: the whole shape of the upper guide plate 3 is a round thick plate, 4 guide post shaft sleeve mounting holes 3-1 and an upper core shaft 1 mandrel placing hole 3-2 are arranged on the upper guide plate 3, the 4 guide post shaft sleeve mounting holes 3-1 are positioned at the edge of the round thick plate, the circle center position of the guide post shaft sleeve mounting hole 3-1 is the same as that of the guide post mounting hole 16-1 on the lower guide plate 16, and the radius is the same as that of the cylindrical surface 6-2 of the guide post shaft sleeve 6 and used for mounting the guide post shaft sleeve 6.
As shown in fig. 10 and 11: the size and the structure of the upper end cover 4 and the lower end cover 4 are completely the same, so the end cover 4 refers to the upper end cover 4 and the lower end cover 4, the end cover 4 is a circular thick plate-shaped structure, and the centroid of the end cover 4 is provided with an upper mandrel 1 and a lower mandrel 15 mounting hole 4-1; the end face of the end cover 4 is provided with a rectangular annular boss 4-2, the shape of the outer side of the cross section of the rectangular annular boss 4-2 is the same as that of the inner side of the cross section of the rectangular tube blank 10, and the size of the outer side of the cross section of the rectangular annular boss 4-2 is slightly smaller than that of the inner side of the cross section of the rectangular tube blank 10 by 0.2-0.5 mm; during assembly, the upper surface of the rectangular annular boss 4-2 is in close contact with the rubber seal ring 14.
As shown in fig. 12 and 13: the upper end die piece 5 is of a round thick plate structure with steps on the inner side and the outer side, and the cross section is of a step shape; a rectangular through hole 5-2 is formed in the middle of the upper die plate 5, and the outline shape and the size of the rectangular through hole 5-2 are the same as those of the outer side of the cross section of the rectangular tube blank 10; a step-shaped structure is arranged at the junction of the large end plane of the upper end template 5 and the rectangular through hole 5-2, the width of the step 5-3 is equal to the ripple height of the rectangular corrugated pipe in target size, the height of the step 5-3 is equal to the ripple thickness of the rectangular corrugated pipe in target size, a round chamfer 5-1 is arranged at the junction of the horizontal plane of the step 5-3 and the rectangular through hole, and the radius of the round chamfer 5-1 is equal to the radius of the trough of the rectangular corrugated pipe in target size; during assembly, the small end of the upper die 5 is horizontally placed upwards.
As shown in fig. 14 and 15: the guide post shaft sleeve 6 is of a circular tubular structure with a circular boss, and a through hole with the same diameter as that of the guide post 7 is formed in the center of the guide post shaft sleeve 6; the bottom of the guide post shaft sleeve 6 is provided with a circular boss with a slightly larger diameter, the diameter of the circular boss is 10-20 mm larger than that of the outer surface 6-2 of the circular tube, and the diameter of the outer surface 6-2 of the circular tube is the same as that of the guide post shaft sleeve mounting hole 3-1 on the upper guide plate 3.
As shown in fig. 16: the guide post 7 is of a cylindrical structure, the diameter of the guide post is the same as that of a guide post mounting hole 16-1 on the lower guide plate 16, and positioning and guiding functions are achieved.
As shown in fig. 17 and 18: the inner die piece 8 of the positioning limiting die adopts a half split die structure, the whole appearance of the positioning limiting die is a half ring with bosses in different shapes on the inner side and the outer side, and a semicircular boss with a step-shaped section is arranged on the outer side of the inner die piece 8 of the positioning limiting die; the inner side of the die 8 in the positioning and limiting die is provided with three bosses, one side of each boss close to the rectangular tube blank 10 is provided with an arc surface 8-1, and a space 8-2 between each boss is obtained by 1/4 circular cutting. During assembly, the matched two positioning shape-limiting die inner dies 8 are placed between the two dies, and then the positioning shape-limiting die outer rings 9 are sleeved on the two positioning shape-limiting die inner dies. The die 8 in the positioning and limiting die is responsible for positioning the die and limiting the bulging shape of the tube blank in the forming process.
As shown in fig. 19 and 20: the outer ring 9 of the positioning shape limiting die is a circular ring with a boss 9-1 on the inner side, and the whole thickness of the outer ring 9 of the positioning shape limiting die is 0.4mm smaller than that of the inner die 8 of the positioning shape limiting die and is used for fixing the inner die 8 of the positioning shape limiting die.
As shown in fig. 21: the cross section of the rectangular tube blank 10 is rectangular with four corners being round corners, and is obtained by bending and welding a plate;
as shown in fig. 22 and 23: the outer ring 11 of the middle die is a circular ring with a boss 11-1 on the inner side, and the whole thickness of the outer ring 11 of the middle die is 0.4mm smaller than that of the inner die 12 of the middle die and is used for fixing the inner die 12 of the middle die.
As shown in fig. 24 and 25: the inner die piece 12 of the middle die adopts a half split die structure, the whole appearance is a flat plate with the outer side outline of 1/2 circles and the inner side outline of 1/2 rectangular notches, and a boss matched with the outer ring 11 of the middle die piece is arranged on the outer side of the inner die piece 12 of the middle die piece; the inner side of the die 12 in the middle die is provided with a boss 12-1 with a rectangular periphery, the thickness of the boss 12-1 is equal to the diameter of a wave trough of a target size of the rectangular corrugated pipe, the thickness of a blank part 12-2 above the boss 12-1 is equal to the diameter of a wave crest of the target size of the rectangular corrugated pipe, and the width of the boss 12-1 is 2-3 mm larger than the wave height of the target size of the rectangular corrugated pipe. During assembly, the matched two inner die sheets 12 of the middle die sheet are firstly arranged above the positioning shape limiting die sheets (8, 9) and sleeved on the rectangular tube blank 10, and finally, the outer ring 11 of the middle die sheet is sleeved to fix the inner die sheets 12 of the middle die sheet.
As shown in fig. 26 and 27: the lower end die 13 is of a round thick plate-shaped structure with a round boss, the end of the round boss is the upper end, the round thick plate at the bottom is the lower end, a rectangular through hole is arranged in the middle of the lower end die 13, and the outline shape and the size of the rectangular through hole are the same as those of the outer side of the cross section of the rectangular tube blank 10; a round chamfer 13-1 is arranged at the junction of the rectangular through hole and the lower end surface of the lower end die piece 13, and the radius of the round chamfer 13-1 is determined according to the radius of a wave trough of a target size of the rectangular corrugated pipe; during assembly, the upper end of the lower die sheet 13 is horizontally placed downwards.
As shown in fig. 28: the rubber sealing rings 14 are of an annular structure with a circular cross section, and the rubber sealing rings 14 are arranged on the upper mandrel 1 and the lower mandrel 15 and used for sealing the upper end and the lower end of the rectangular tube blank 10.
As shown in fig. 29 and 30: the lower mandrel 15 comprises a rectangular bottom plate and a mandrel, the rectangular bottom plate is of a stepped structure and is positioned at the bottom, the mandrel is of a cylindrical structure, the diameter of the lower end of the cylindrical structure is larger than that of the upper end of the cylindrical structure, the cylindrical structure is positioned above the rectangular bottom plate, threads are arranged on the upper end and the lower end of the mandrel, the upper end thread 15-2 of the mandrel is used for connecting a liquid conduit of a hydraulic pump, and the lower end thread 15-3 is matched with the fastening nut 2; a circular through hole 15-1 is formed in the center of the mandrel of the lower mandrel 15 and penetrates through the mandrel and the rectangular bottom plate; the threaded end of the lower mandrel 15 is horizontally placed downwards and is arranged above the lower end cover 4, and the mandrel passes through a mandrel shaft hole 4-1 on the lower end cover 4 and is fixed by a fastening nut 2.
As shown in fig. 31: the whole shape of the lower guide plate 16 is a round thick plate, 4 guide pillar mounting holes 16-1 and a lower mandrel 15 mandrel placing hole are formed in the lower guide plate 16, the 4 guide pillar mounting holes 16-1 are located at the edge of the round thick plate, the radius of the guide pillar mounting holes 16-1 is equal to that of the guide pillars 7, and the distance between the edge of the guide pillar mounting holes 16-1 and the edge of the positioning limiting die piece outer ring 9 is 0.5-1 mm.
As shown in fig. 32: the secondary wave-starting positioning block 17 is of a cuboid structure, the height of the secondary wave-starting positioning block is equal to the distance between the dies during secondary wave-starting, and the secondary wave-starting positioning block is mainly used for positioning the dies.
With reference to fig. 1 to 5, a three-step hydraulic precise forming method for a rectangular corrugated pipe comprises the following steps:
the method comprises the following steps: manufacturing a rectangular tube blank;
the manufacturing of the rectangular tube blank comprises the following three steps of material preparation, bending and welding: cutting an original strip into a rectangular strip with a certain length and width, determining the arc center position of a rectangular transition fillet on the long side of the rectangular strip, pressing four transition fillets of a rectangular tube blank through bending equipment, and finally obtaining the rectangular tube blank with only one welding line through welding;
step two: assembling a mould;
sleeving a rubber sealing ring 14 on a lower mandrel 15, and connecting and fixedly assembling a lower end cover 4 and the lower mandrel 15 together through a fastening nut 2; the lower guide plate 16 is flatly placed on a platform of the hydraulic machine, after a liquid guide pipe of the hydraulic pump passes through a mandrel placing hole of a lower mandrel 15 on the lower guide plate 16 and is connected with the lower mandrel 15, the lower end cover 4 and an assembly body of the lower mandrel 15 are placed above the lower guide plate 16, and the mandrel of the lower mandrel 15 is placed downwards; marking the upper end and the lower end of a rectangular tube blank 10, sleeving a lower end matrix 13 outside the lower end of the rectangular tube blank 10, aligning the end surface of a circular boss end of the lower end matrix 13 with the edge of the lower end of the rectangular tube blank 10, and assembling the lower end matrix 13 and the rectangular tube blank 10 above a lower end cover 4 and a lower mandrel 15 assembly; two matched positioning shape limiting die inner dies 8 are placed above the lower end die 13 and spliced together, and the positioning shape limiting die inner dies 8 are fixed by the positioning shape limiting die outer rings 9; two matched inner die sheets 12 of the middle die sheet are placed above the positioning shape limiting die sheets (8, 9) and spliced together, and the inner die sheets 12 of the middle die sheet are fixed by an outer ring 11 of the middle die sheet; sequentially assembling positioning limiting dies (8, 9) and intermediate dies (11, 12), wherein the positioning limiting dies (8, 9) and the intermediate dies (11, 12) are alternately arranged, and the number of the positioning limiting dies is determined by the wave number of the rectangular corrugated pipe; after the last positioning limiting mold piece (8, 9) is assembled, the upper mold piece 5 is sleeved at the upper end of the rectangular tube blank 10; starting a hydraulic pump, and closing the hydraulic pump when the internal cavity of the rectangular tube blank 10 is filled with liquid; the rubber sealing ring 14 is sleeved on the upper mandrel 1, the upper end cover 4 and the upper mandrel 1 are connected and fixedly assembled together through the fastening nut 2, and the upper end cover 4 and the upper mandrel 1 assembly body are assembled above the rectangular tube blank 10; finally, four guide posts 7 are inserted, and the upper guide plate 3 with the shaft sleeve 6 assembled is arranged at the top through the four guide posts 7.
Step three: primary wave starting;
pressure P in the primary wave1The calculation formula of (a) is as follows:
in the formula, t is the wall thickness (mm) of the rectangular tube blank;
σb-material tensile strength (MPa);
Dtransition fillet-the diameter (mm) of the transition fillets of the rectangular tube blank;
the pressure head of the press is downward, the hydraulic pump is started after the upper guide plate 3 is tightly pressed, so that liquid continuously flows to the inner cavity of the rectangular tube blank 10 through the liquid guide pipe of the hydraulic pump, and when the internal pressure reaches P1When the pressure is higher than the preset pressure, the hydraulic pump is closed, and the internal pressure is reduced to 0 MPa.
Step four: secondary wave generation;
the press head moves upwards, the upper guide plate 3 is taken down, the guide post 7 is pulled out, all the positioning shape limiting die sheets outer rings 9 and the positioning shape limiting die sheets inner die sheets 8 are sequentially disassembled, and meanwhile, the secondary wave-generating positioning blocks 17 are arranged between the die sheets to play a positioning role.
Pressure P in secondary wave2The calculation formula of (a) is as follows:
in the formula, t is the wall thickness (mm) of the rectangular tube blank;
σb-material tensile strength (MPa);
l is the length (mm) of the rectangular cross section of the rectangular tube blank; (including transition fillets)
W is the width (mm) of the rectangular cross section of the rectangular tube blank; (including transition fillets)
Installing the guide post 7 and the upper guide plate 3, enabling a pressure head of the press to be downward, starting the hydraulic pump after the upper guide plate 3 is pressed, and enabling the internal pressure to reach P2When the pressure is higher than the preset pressure, the hydraulic pump is closed, and the internal pressure is reduced to 0 MPa.
Step five: hydroforming;
moving the pressure head of the press upwards, and taking down all the secondary wave-starting positioning blocks 17; the pressure head of the press moves downwards to apply a certain pressure to the upper guide plate 3; starting the hydraulic pump when the internal pressure reaches P2When the mold piece is completely closed, the pressure head of the press continues to move downwards;
step six: taking out the workpiece;
closing the hydraulic pump, moving a pressure head of the press upwards, sequentially taking down the upper guide plate 3, the guide pillar 7, the upper end cover 4, the upper core shaft 1 assembly body, the upper end matrix 5, the middle matrixes (11 and 12) and the lower end matrix 13, and taking out the rectangular metal corrugated pipe workpiece;
as shown in fig. 33, compared with the conventional two-step hydraulic bulging process, the rectangular metal corrugated pipe is prepared by adopting the rectangular corrugated pipe three-step hydraulic precise forming method and the die, the obtained product has uniform wave height and wave shape at the transition round corner and the straight line section, the forming result is precise, the product performance is good, and because only one forming process is adopted for forming, the disassembly of the formed membranes (the upper end membrane 5, the middle membranes (11, 12) and the lower end membrane 13) is not involved in the forming process, the forming process is simple, the production efficiency is high, and the manufacturing cost is low.
Claims (10)
1. The utility model provides a three step hydraulic pressure accurate forming die of rectangle bellows, its characterized in that, lower baffle (16) are kept flat on the hydraulic press platform, lower core axle (15) and lower extreme cover (4) have been placed to lower baffle (16) central surface, the cover has rectangle pipe (10) on the assembly body that lower core axle (15) and lower extreme cover (4) formed, the outside cover of rectangle pipe (10) lower extreme has lower extreme diaphragm (13), and lower extreme diaphragm (13) and lower extreme cover (4) contact, the top of lower extreme diaphragm (13), the outside of rectangle pipe (10) are provided with location limit diaphragm and middle diaphragm in turn, and the superiors and the lower floor are location limit diaphragm, and the top of the superiors location limit diaphragm is provided with upper end (5), and upper end diaphragm (5) cover is in the outside of rectangle pipe (10) upper end, rectangle pipe (10) upper end inboard is provided with upper end cover (4) and upper core axle (1), the upper core shaft (1) and the lower core shaft (15) are in the same axis position, an upper guide plate (3) is arranged above the upper end cover (4) and the upper core shaft (1), four guide post shaft sleeve mounting holes are formed in the surface of the upper guide plate (3), four guide post mounting holes are formed in the surface of the lower guide plate (16), the guide post shaft sleeve mounting holes in the upper guide plate (3) and the guide post mounting holes in the lower guide plate (16) are arranged around the rectangular tube blank (10) at equal intervals, and guide posts (7) penetrate through the guide post mounting holes in the lower guide plate (16) and the guide post mounting holes in the upper shaft sleeve (6) of the upper guide plate (3).
2. The three-step hydraulic precise forming die for the rectangular corrugated pipe as claimed in claim 1, wherein the upper mandrel (1) comprises a mandrel (1-1) and a rectangular bottom plate (1-2), and the rectangular bottom plate (1-2) is of a stepped structure and is positioned at the bottom of the upper mandrel (1); the mandrel (1-1) is of a cylindrical structure, threads matched with the fastening nut (2) are arranged on the mandrel (1-1), and the mandrel (1-1) is positioned at a centroid above the rectangular bottom plate (1-2); the fastening nut (2) is used for connecting and fixing the upper mandrel (1) and the upper end cover (4), and the lower mandrel (15) and the lower end cover (4);
the lower mandrel (15) comprises a rectangular bottom plate and a mandrel, the rectangular bottom plate is of a stepped structure and is positioned at the bottom, the mandrel is of a cylindrical structure, the diameter of the lower end of the cylindrical structure is larger than that of the upper end of the cylindrical structure, the cylindrical structure is positioned above the rectangular bottom plate, threads are arranged at the upper end and the lower end of the mandrel, the upper end thread (15-2) of the mandrel is used for connecting a liquid conduit of a hydraulic pump, and the lower end thread (15-3) is matched with the fastening nut (2); a circular through hole (15-1) is formed in the center of the mandrel of the lower mandrel (15) and penetrates through the mandrel and the rectangular bottom plate; the threaded end of the lower mandrel (15) is horizontally placed downwards and is arranged above the lower end cover (4), and the mandrel passes through a mandrel shaft hole (4-1) on the lower end cover (4) and is fixed by a fastening nut (2).
3. The three-step hydraulic precise forming die for the rectangular corrugated pipe as claimed in claim 1, wherein the overall shape of the upper guide plate (3) is a round thick plate, 4 guide post and shaft sleeve mounting holes (3-1) and a mandrel placing hole (3-2) of the upper mandrel (1) are formed in the upper guide plate (3), the 4 guide post and shaft sleeve mounting holes (3-1) are formed in the edge of the round thick plate, the circle center position of each guide post and shaft sleeve mounting hole (3-1) is the same as that of a guide post and shaft sleeve mounting hole (16-1) in the lower guide plate (16), and the radius of each guide post and shaft sleeve mounting hole is the same as that of a cylindrical surface (6-2) of the guide post and shaft sleeve (6) for mounting the guide post and shaft sleeve (6);
the whole shape of the lower guide plate (16) is a round thick plate, 4 guide post mounting holes (16-1) and a mandrel placing hole of a lower mandrel (15) are formed in the lower guide plate (16), the 4 guide post mounting holes (16-1) are located at the edge of the round thick plate, the radius of the guide post mounting holes is equal to that of the guide posts (7), and a gap is formed between the edge of the guide post mounting holes (16-1) and the edge of the positioning limiting die piece outer ring (9);
the size and the structure of the upper end cover and the lower end cover are completely the same, the end covers (4) are the upper end cover (4) and the lower end cover (4), the end covers (4) are in a circular thick plate-shaped structure, and the centroid of each end cover (4) is provided with an upper mandrel (1) and a lower mandrel (15) mounting hole (4-1); the end face of the end cover (4) is provided with a rectangular annular boss (4-2), the shape of the outer side of the cross section of the rectangular annular boss (4-2) is the same as that of the inner side of the cross section of the rectangular tube blank (10), and the size of the outer side of the cross section of the rectangular annular boss (4-2) is smaller than that of the inner side of the cross section of the rectangular tube blank (10).
4. The three-step hydraulic precise forming die for the rectangular corrugated pipe as claimed in claim 1, wherein the upper die sheet (5) is of a round thick plate structure with steps on the inner side and the outer side, and the cross section is stepped; a rectangular through hole (5-2) is formed in the middle of the upper die plate (5), and the outline shape and the size of the rectangular through hole (5-2) are the same as those of the outer side of the cross section of the rectangular tube blank (10); a step-shaped structure is arranged at the junction of the large end plane of the upper end template (5) and the rectangular through hole (5-2), the width of the step (5-3) is equal to the ripple height of the rectangular corrugated pipe in the target size, the height of the step (5-3) is equal to the ripple thickness of the rectangular corrugated pipe in the target size, a round chamfer (5-1) is arranged at the junction of the horizontal plane of the step (5-3) and the rectangular through hole, and the radius of the round chamfer (5-1) is equal to the radius of the trough of the rectangular corrugated pipe in the target size;
the lower end die piece (13) is of a round thick plate-shaped structure with a round boss, the end of the round boss is the upper end, the round thick plate below is the lower end, a rectangular through hole is formed in the middle of the lower end die piece (13), and the outline shape and the size of the rectangular through hole are the same as those of the outer side of the cross section of the rectangular tube blank (10); a round chamfer (13-1) is arranged at the junction of the rectangular through hole and the lower end surface of the lower end template (13), and the radius of the round chamfer (13-1) is determined according to the radius of a wave trough of the target size of the rectangular corrugated pipe.
5. The three-step hydraulic precise forming die for the rectangular corrugated pipe as claimed in claim 1, wherein the guide post sleeve (6) is of a circular tubular structure with a circular boss, and a through hole with the same diameter as that of the guide post (7) is formed in the center of the guide post sleeve (6); the bottom of the guide post shaft sleeve (6) is provided with a circular boss with a slightly larger diameter, the diameter of the circular boss is larger than that of the outer surface (6-2) of the circular tube, and the diameter of the outer surface (6-2) of the circular tube is the same as that of a guide post shaft sleeve mounting hole (3-1) on the upper guide plate (3); the guide post (7) is of a cylindrical structure, the diameter of the guide post is the same as that of a guide post mounting hole (16-1) on the lower guide plate (16), and positioning and guiding functions are achieved.
6. The three-step hydraulic precise forming die for the rectangular corrugated pipe as claimed in claim 1, wherein the positioning and shape-limiting die comprises an inner die (8) and an outer ring (9), the inner die (8) of the positioning and shape-limiting die is of a half-split die structure, the overall shape of the inner die is a half-ring with bosses of different shapes on the inner side and the outer side, and the outer side of the inner die (8) of the positioning and shape-limiting die is provided with a semicircular boss with a step-shaped section; three bosses are arranged on the inner side of the die piece (8) in the positioning and limiting die, an arc surface (8-1) is arranged on one side of each boss close to the rectangular tube blank (10), and a space (8-2) between each boss is obtained by 1/4 circular cutting; the positioning shape-limiting die sheet outer ring (9) is a circular ring with a boss (9-1) at the inner side, and the whole thickness of the positioning shape-limiting die sheet outer ring (9) is smaller than that of the die sheet 8 in the positioning shape-limiting die sheet and is used for fixing the die sheet (8) in the positioning shape-limiting die sheet;
the cross section of the rectangular tube blank (10) is rectangular with four corners being round corners, and the rectangular tube blank is obtained by bending and welding a plate;
the middle die comprises a middle die outer ring (11) and a middle die inner die (12), the middle die outer ring (11) is a circular ring with a boss (11-1) on the inner side, and the whole thickness of the middle die outer ring (11) is smaller than that of the middle die inner die (12) and is used for fixing the middle die inner die (12); the inner die piece (12) of the middle die adopts a half split die structure, the whole appearance of the middle die piece is a flat plate with an outer side outline of 1/2 circles and an inner side outline of 1/2 rectangular notches, and a boss matched with the outer ring (11) of the middle die piece is arranged on the outer side of the inner die piece (12) of the middle die piece; a boss (12-1) with a rectangular circumference is arranged on the inner side of the die piece (12) in the middle die, the thickness of the boss (12-1) is equal to the diameter of a wave trough of the target size of the rectangular corrugated pipe, and the thickness of a blank part (12-2) above the boss (12-1) is equal to the diameter of a wave crest of the target size of the rectangular corrugated pipe.
7. The three-step hydraulic precise forming die for the rectangular corrugated pipe as claimed in claim 1, wherein the upper mandrel (1) and the lower mandrel (15) are provided with rubber sealing rings (14), and the rubber sealing rings (14) are of annular structures with circular cross sections and are used for sealing the upper end and the lower end of the rectangular pipe blank (10).
8. The three-step hydraulic precise forming die for the rectangular corrugated pipe as claimed in claim 1, wherein the secondary wave-forming positioning block (17) is a rectangular parallelepiped structure, and the height of the secondary wave-forming positioning block is equal to the distance between the dies during secondary wave-forming, so that the dies can be positioned.
9. The method for precisely forming the die for the rectangular corrugated pipe in the three-step hydraulic pressure based on any one of claims 1 to 8 is characterized by comprising the following steps of:
the method comprises the following steps: manufacturing a rectangular tube blank (10);
the manufacturing of the rectangular tube blank (10) comprises the following three steps of material preparation, bending and welding: cutting an original strip into a rectangular strip with a certain length and width, determining the arc center position of a rectangular transition fillet on the long side of the rectangular strip, pressing the rectangular tube blank (10) transition fillets through bending equipment, and finally obtaining the rectangular tube blank (10) with only one welding line through welding;
step two: assembling a mould;
sleeving a rubber sealing ring (14) on a lower mandrel (15), and connecting and fixedly assembling a lower end cover (4) and the lower mandrel (15) together through a fastening nut (2); the lower guide plate (16) is horizontally placed on a platform of the hydraulic machine, a liquid guide pipe of the hydraulic pump penetrates through a mandrel placing hole of a lower mandrel (15) on the lower guide plate (16) and is connected with the lower mandrel (15), then a lower end cover (4) and a lower mandrel (15) assembly body are placed above the lower guide plate (16), and the mandrel of the lower mandrel (15) is placed downwards; marking the upper end and the lower end of a rectangular tube blank (10), sleeving a lower end template (13) outside the lower end of the rectangular tube blank (10), aligning the end surface of a circular boss of the lower end template (13) with the edge of the lower end of the rectangular tube blank (10), and assembling the lower end template (13) and the rectangular tube blank (10) above a lower end cover (4) and a lower mandrel (15) assembly; two matched positioning shape limiting die inner dies (8) are placed above the lower end die (13) and spliced together, and the positioning shape limiting die inner dies (8) are fixed by a positioning shape limiting die outer ring (9); two matched inner matrixes (12) of the middle mould are placed above the positioning shape-limiting matrixes and spliced together, and the inner matrixes (12) of the middle mould are fixed by an outer ring (11) of the middle mould; sequentially assembling positioning shape limiting dies and intermediate dies, wherein the positioning shape limiting dies and the intermediate dies are alternately arranged, and the number of the positioning shape limiting dies and the intermediate dies is determined by the wave number of the rectangular corrugated pipe; after the last positioning limiting die piece is assembled, the upper end die piece (5) is sleeved at the upper end of the rectangular tube blank (10); starting a hydraulic pump, and closing the hydraulic pump when the internal cavity of the rectangular tube blank (10) is filled with liquid; the rubber sealing ring (14) is sleeved on the upper mandrel (1), the upper end cover (4) and the upper mandrel (1) are connected and fixedly assembled together through the fastening nut (2), and the upper end cover (4) and the upper mandrel (1) assembly body is assembled above the rectangular tube blank (10); finally, four guide posts (7) are inserted, and the upper guide plate (3) provided with the shaft sleeve (6) penetrates through the four guide posts (7) to be arranged at the top;
step three: primary wave starting;
pressure P in the primary wave1The calculation formula of (a) is as follows:
in the formula, t is the wall thickness (mm) of the rectangular tube blank;
σb-material tensile strength (MPa);
Dtransition fillet-the diameter (mm) of the transition fillets of the rectangular tube blank;
the pressure head of the press is downward, the hydraulic pump is started after the upper guide plate (3) is pressed, so that liquid continuously flows to the inner cavity of the rectangular tube blank (10) through the liquid guide pipe of the hydraulic pump, and when the internal pressure reaches P1When the pressure is higher than the preset pressure, the hydraulic pump is closed, and the internal pressure is reduced to 0 MPa;
step four: secondary wave generation;
the pressure head of the press moves upwards, the upper guide plate (3) is taken down, the guide post (7) is pulled out, all the positioning shape limiting die sheet outer rings (9) and the positioning shape limiting die sheet inner die sheets (8) are sequentially disassembled, and meanwhile, the secondary wave-generating positioning blocks (17) are arranged between the die sheets to play a positioning role;
pressure P in secondary wave2The calculation formula of (a) is as follows:
in the formula, t is the wall thickness (mm) of the rectangular tube blank;
σb-material tensile strength (MPa);
l is the length (mm) of the rectangular cross section of the rectangular tube blank; (including transition fillets)
W is the width (mm) of the rectangular cross section of the rectangular tube blank; (including transition fillets)
Installing a guide post (7) and an upper guide plate (3), enabling a pressure head of the press to be downward, starting the hydraulic pump after the upper guide plate (3) is pressed, and enabling the internal pressure to reach P2When the pressure is higher than the preset pressure, the hydraulic pump is closed, and the internal pressure is reduced to 0 MPa;
step five: hydroforming;
moving the pressure head of the press upwards, and taking down all the secondary wave-starting positioning blocks 17; the pressure head of the press moves downwards to apply a certain pressure to the upper guide plate (3); starting the hydraulic pump when the internal pressure reaches P2When the mold piece is completely closed, the pressure head of the press continues to move downwards;
step six: taking out the workpiece;
and (3) closing the hydraulic pump, moving a pressure head of the press upwards, sequentially taking down the upper guide plate (3), the guide pillar (7), the upper end cover (4), the upper core shaft (1) assembly body, the upper end die sheet (5), the middle die sheet and the lower end die sheet (13), and taking out the rectangular metal corrugated pipe workpiece.
10. The method for precisely forming the die by the three-step hydraulic pressure for the rectangular corrugated pipe as claimed in claim 9, wherein the forming method can be used for precisely forming the rectangular metal corrugated pipe and is also suitable for precisely forming the metal corrugated pipe with the special-shaped structure, which has different structures at different positions of the circumferential profile, such as a runway shape and the like;
the forming method can be used for manufacturing the rectangular metal corrugated pipe with 1 layer, 2 layers and multiple layers; when the rectangular metal corrugated pipes with different layers are formed, rectangular pipe blanks with corresponding layers can be prepared according to the first step, and the rest steps are the same;
the forming method can be used for precisely forming the metal corrugated pipe with the special-shaped structure, such as a rectangular corrugated pipe with a C-shaped, V-shaped, U-shaped, W-shaped and omega-shaped cross section, a runway-shaped corrugated pipe and the like, but not limited to the special-shaped structure; when the metal corrugated pipes with special-shaped structures such as rectangles, racetrack shapes and the like with different waveform cross sections are formed, the forming method is unchanged, and the forming die is correspondingly modified according to the structure and the size of a workpiece.
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| CN202110451347.8A CN113290101B (en) | 2021-04-26 | 2021-04-26 | Three-step hydraulic precise forming die and method for rectangular corrugated pipe |
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| CN202110451347.8A CN113290101B (en) | 2021-04-26 | 2021-04-26 | Three-step hydraulic precise forming die and method for rectangular corrugated pipe |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115870366A (en) * | 2022-10-31 | 2023-03-31 | 江苏恒高电气制造有限公司 | Coaxial forming method for stainless steel multilayer corrugated pipe |
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| JP2012218024A (en) * | 2011-04-08 | 2012-11-12 | Nippon Shinshukukan Kk | Method and apparatus for manufacturing bellows |
| CN203002882U (en) * | 2013-01-11 | 2013-06-19 | 乌鲁木齐苏泰开元波纹管有限公司 | Vertical multiwave one-step forming device for medium-caliber corrugated pipe |
| CN103252408A (en) * | 2012-02-16 | 2013-08-21 | 泰州华腾管道设备有限公司 | Combined bellows molding die sheet with bolt connection structure |
| CN203390028U (en) * | 2013-07-19 | 2014-01-15 | 福建恒盛管业有限公司 | Square corrugated pipe molding module |
| CN103611768A (en) * | 2012-11-29 | 2014-03-05 | 重庆帆城科技有限公司 | Hydraulic forming technology of tube blank of small-sized corrugated tube and forming die sheet special for tube blank of small-sized corrugated tube |
| CN206779216U (en) * | 2017-05-27 | 2017-12-22 | 潘太兴 | A kind of fully automatic vacuum corrugated pipe forming machine |
| CN107952859A (en) * | 2018-01-08 | 2018-04-24 | 西安石油大学 | A kind of detachable hydraulic expanding die for being used to manufacture S type metal bellows |
| CN111250586A (en) * | 2020-03-13 | 2020-06-09 | 沈阳晨光弗泰波纹管有限公司 | Swift formula bellows forming die guiding orientation frock |
| CN111438223A (en) * | 2020-04-03 | 2020-07-24 | 西安石油大学 | Integral forming method for rectangular metal corrugated pipe |
| CN111496043A (en) * | 2020-04-14 | 2020-08-07 | 西安石油大学 | Combined hydraulic bulging die for manufacturing rectangular metal corrugated pipe |
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2021
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| JPS493619B1 (en) * | 1969-01-31 | 1974-01-28 | ||
| JP2012218024A (en) * | 2011-04-08 | 2012-11-12 | Nippon Shinshukukan Kk | Method and apparatus for manufacturing bellows |
| CN103252408A (en) * | 2012-02-16 | 2013-08-21 | 泰州华腾管道设备有限公司 | Combined bellows molding die sheet with bolt connection structure |
| CN103611768A (en) * | 2012-11-29 | 2014-03-05 | 重庆帆城科技有限公司 | Hydraulic forming technology of tube blank of small-sized corrugated tube and forming die sheet special for tube blank of small-sized corrugated tube |
| CN203002882U (en) * | 2013-01-11 | 2013-06-19 | 乌鲁木齐苏泰开元波纹管有限公司 | Vertical multiwave one-step forming device for medium-caliber corrugated pipe |
| CN203390028U (en) * | 2013-07-19 | 2014-01-15 | 福建恒盛管业有限公司 | Square corrugated pipe molding module |
| CN206779216U (en) * | 2017-05-27 | 2017-12-22 | 潘太兴 | A kind of fully automatic vacuum corrugated pipe forming machine |
| CN107952859A (en) * | 2018-01-08 | 2018-04-24 | 西安石油大学 | A kind of detachable hydraulic expanding die for being used to manufacture S type metal bellows |
| CN111250586A (en) * | 2020-03-13 | 2020-06-09 | 沈阳晨光弗泰波纹管有限公司 | Swift formula bellows forming die guiding orientation frock |
| CN111438223A (en) * | 2020-04-03 | 2020-07-24 | 西安石油大学 | Integral forming method for rectangular metal corrugated pipe |
| CN111496043A (en) * | 2020-04-14 | 2020-08-07 | 西安石油大学 | Combined hydraulic bulging die for manufacturing rectangular metal corrugated pipe |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115870366A (en) * | 2022-10-31 | 2023-03-31 | 江苏恒高电气制造有限公司 | Coaxial forming method for stainless steel multilayer corrugated pipe |
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