Annular double-wave corrugated pipe continuous roll forming device and method thereof

Abstract

The present application relates to a kind of annular double-wave corrugated pipe continuous roll forming device and method thereof, the device includes cold bending roller group, welding mechanism, traction mechanism and rolling mechanism;The welding mechanism is correspondingly arranged on the outlet side of cold bending roller group upper side;The traction mechanism is correspondingly arranged in the front of cold bending roller group outlet side;The rolling mechanism is correspondingly arranged in the front of the outlet side of traction mechanism;The rolling mechanism includes three groups of initial rolling mechanism and a group of finishing rolling mechanism in turn evenly arranged.According to the parameter requirement of double-wave corrugated pipe, according to the pre-defined parallel double helix curve control thin-walled welded pipe 1-4 pass gradual spinning forming: 1-3 pass adopts equal pitch, equal tooth thickness, double helix screw thread forming with equal outer diameter, the fourth pass adopts gradually changing pitch, gradually changing tooth thickness and gradually changing outer diameter double helix screw thread forming, can effectively solve the problem of abrupt change of adjacent two waveforms and forming speed, make double-wave corrugated pipe forming process more moderate, thereby significantly improve the bending fatigue life of double-wave corrugated pipe.

Description

Technical Field

[0001] This invention relates to the field of flexible pipe processing technology, and in particular to a continuous roll forming apparatus and method for annular double-wave corrugated pipes. Background Technology

[0002] Stainless steel annular square corrugated pipe is a type of small-diameter stainless steel flexible metal hose, typically made from thin-walled stainless steel through rolling, welding, and spinning. Double-corrugated pipe is a flexible metal hose with annular large and small corrugations. During bending, the smaller corrugations achieve a smaller bending radius under the bending and compression of the larger corrugations, resulting in better bending performance and fatigue life compared to single-corrugated pipes. Due to its advantages of high flexibility, high rigidity, high pressure resistance, and material saving, it is often used as a flexible pipeline connector to withstand various pulse, torsional, and bending loads.

[0003] In existing technology, the study "Research on the Failure Mechanism of Repeated Bending of Metal Corrugated Pipes and its Structural Optimization and Performance Control" discloses a U-shaped metal corrugated pipe with alternating large and small corrugations to meet the working conditions of extreme bending. The purpose is to enhance the maximum bending angular displacement compensation capability of the corrugated pipe when it undergoes large bending deformation, based on the different structural parameters of adjacent waveforms. However, the paper only mentions the use of hydraulic forming and does not cover the relevant mechanical rolling forming methods and mechanisms.

[0004] In addition, Chinese patent CN112091027B discloses a roll forming machine for seamless thin-walled corrugated pipes of fixed length, including a frame, a traction mechanism, a forming mechanism, a discharge mechanism, an oil tank, a lubrication tank, and a central control system. The traction mechanism and forming mechanism are mounted on the frame, with the forming mechanism located between the traction mechanism and the feeding mechanism. The seamless thin-walled pipe enters the forming mechanism through the traction mechanism for roll forming, and the formed corrugated pipe is discharged as a finished product through the discharge mechanism. However, this technical solution is only suitable for the production of seamless corrugated pipes and hoses of fixed length. Due to the use of a single forming mechanism, the forming efficiency is low, continuous production cannot be achieved, and only single-corrugated pipes of a single model can be produced.

[0005] Chinese patent CN114589225A discloses a corrugated pipe forming device, including a support block, a bearing, a mold, and a fastening ring. The support block is powered by a rotary motor, and the outer ring of the bearing is embedded in the support block. The pressure of the mold can be controlled by adjusting screws inside the support block. The mold is embedded in the inner ring of the bearing, and the rotary motor drives the support block to rotate, achieving both self-rotation and circumferential rotation forming around the inner diameter of the hose. However, this patent's technical solution is a single-mold internal spin forming, mainly targeting small-diameter double-arc corrugated hoses, resulting in limited product models and low efficiency and precision.

[0006] Chinese patent CN107755497B discloses a metal sheath corrugating machine, including a cutter head, guide rod, sliding cutter holder, rotating shaft, corrugating cutter, and pusher. Cable or optical cable sheaths enter the corrugating mechanism via a guiding mechanism. The forming cutter head rotates around the cable sheath under the drive of a rotary motor. The corrugating cutter, adjusted according to the required corrugation depth, rolls a corrugated tubular shape onto the cable sheath. However, this patent's technical solution also uses a single-mold internal spinning mode for corrugation forming, primarily targeting single-corrugation rolling of cable sheaths, and thus suffers from insufficient rolling precision.

[0007] Chinese patent CN113319149B discloses an integrated forming equipment for producing annular corrugated metal pipes, comprising a feeding machine, a welding machine, a traction machine, a forming machine, a shaping machine, a cleaning machine, and a receiving machine arranged sequentially. Steel strips are placed on the feeding machine, gradually rolled into round tubes by a rolling device, then welded into welded pipes by the welding machine. The pipes are then sequentially fed into the forming and shaping machines by the traction device, and the entire process is completed through cleaning and rewinding of the finished product. This scheme uses internal spinning forming for the first three passes and three-roller external forming for the fourth pass. Although this technical solution represents a significant optimization compared to previous solutions, achieving online continuous forming and welding of corrugated metal pipes, it still does not propose or solve a method or implementation for producing double-corrugated pipes, and also suffers from the problem of product structure uniformity.

[0008] Chinese patent CN215355623U discloses a forming die for producing annular metal bellows, including a housing, chuck, jaws, and gradually tapered pitch rollers. After the annular initial wave bellows enters the forming die, it is spun into a standard annular metal bellows by three gradually tapered pitch rollers. This patent is a structural supplement to Chinese patent CN113319149B, which describes an integrated forming device for producing annular metal bellows. Although this technical solution proposes external spinning forming with a gradually tapered die, it does not provide a specific forming method or product structure. The structural form is relatively simple and suitable for single-wave rolling.

[0009] Chinese patent CN114749555A discloses a metal hose forming device and its forming method, including a worktable, a rolling mechanism, a steel pipe rounding mechanism, a lubrication mechanism, a first shallow wave forming mechanism, a second shallow wave forming mechanism, a third shallow wave forming mechanism, a dense wave forming mechanism, and a high-pressure cleaning mechanism. This patent operates on the same principle as an integrated forming device for producing annular metal corrugated pipes disclosed in document CN113319149B, and also suffers from the problem of a single product structure, primarily designed for specific diameter products, and unable to meet the production needs of corrugated pipes of various specifications.

[0010] In summary, although existing technologies have proposed beneficial innovative solutions from multiple perspectives, most of them adopt internal spinning, internal and external composite spinning processes, or single-wave hydraulic expansion technology. While these technologies can solve the problems of ordinary single-wave corrugated pipe spinning or multi-wave hydraulic forming to a certain extent, they have failed to achieve an integrated mechanical rolling or spinning forming technology solution for double-wave corrugated pipes. They have also failed to solve the core manufacturing process for mass production of double-wave corrugated pipes. Furthermore, the equipment or product structure is simple and cannot be compatible with multiple product models. At the same time, the convenience of mold replacement has not been considered. Summary of the Invention

[0011] To address the aforementioned problems, the present invention aims to provide a continuous roll forming device and method for annular double-corrugated pipes. It proposes for the first time a full-pass external roll forming technology for double-corrugated pipes, which can efficiently and effectively meet the production and manufacturing needs of double-corrugated hoses under different operating conditions. It features high forming efficiency and good product precision, and can also achieve online integrated continuous forming and switching between multiple product models.

[0012] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0013] The present invention proposes a continuous roll forming device for annular double-wave corrugated pipe, comprising a cold bending roll group, a welding mechanism, a traction mechanism, and a rolling mechanism; the welding mechanism is correspondingly arranged above the exit side of the cold bending roll group; the traction mechanism is correspondingly arranged in front of the exit side of the cold bending roll group; the rolling mechanism is correspondingly arranged in front of the exit side of the traction mechanism; the rolling mechanism includes three sets of initial rolling mechanisms and one set of finishing rolling mechanisms arranged in sequence and evenly.

[0014] Furthermore, both the primary rolling mechanism and the finishing rolling mechanism are composed of three circumferentially distributed annular rolling dies, and the outer side of the rolling dies is surrounded by parallel double-helix curve screw teeth for rolling corrugated tubes; the three circumferentially distributed rolling dies are all coaxially equipped with roller shafts at their axial center positions, and each roller shaft is coaxially equipped with a synchronous gear at its tail end. The three synchronous gears are connected by a synchronous belt to ensure the synchronous operation of the three rolling dies; and the front end of each roller shaft is connected to a rotary mechanism.

[0015] Furthermore, the double-helix curve screw teeth on the outer side of the rolling die of the primary rolling mechanism are all designed with 1.5 turns of equal pitch, equal tooth thickness, and equal outer diameter, and the tooth pitch between adjacent screw teeth is P′. n1 and P′ n2 .

[0016] Furthermore, the double-helix curve screw teeth on the outer side of the finishing mill die adopt a combination design of 4 turns and 3 turns with variable pitch, variable tooth thickness, and variable outer diameter; the tooth pitch of adjacent screw teeth is P′. 41 、P′ 42 、P′ 43、P′ 44 、P′ 45 、P′ 46 、P′ 47 and P′ 48 .

[0017] Furthermore, guide sleeves are provided on both the inlet and outlet sides of the primary rolling mechanism and the finishing rolling mechanism.

[0018] A method for continuous roll forming of annular double-wave corrugated pipe includes the following steps:

[0019] S1. Stainless steel strips are passed sequentially through a cold bending roller group and a welding mechanism to prefabricate thin-walled stainless steel longitudinal seam welded pipes online.

[0020] S2. The thin-walled stainless steel welded pipe is fed into the first set of initial rolling mechanism by the traction mechanism, and the initial three-roll rolling of the thin-walled stainless steel pipe is carried out according to the predefined parallel double helix curve screw teeth to preform the double wave square tube blank.

[0021] S3. The pre-formed double-wave square tube blank in step S2 is fed into the second set of primary rolling mechanism, and the trough-deep rolling and peak extrusion are performed according to the predefined parallel double-helix curve screw teeth to pre-form the double-wave square tube blank.

[0022] S4. The pre-formed double-wave square tube blank in step S3 is fed into the third set of primary rolling mechanism, and the valley and peak of the wave are further pressed and extruded according to the predefined parallel double-helix curve screw teeth to pre-form the double-wave square tube blank.

[0023] S5. The pre-formed double-wave square tube blank from step S4 is fed into the finishing rolling mechanism. The tube blank is then subjected to final finishing rolling and straightening according to the predefined parallel double-helix curve screw teeth with variable outer diameter, variable pitch, and variable tooth thickness to form a precision double-wave corrugated tube.

[0024] Furthermore, three circumferentially distributed rolling dies perform pure rolling spinning around the trough of the tube blank, and the forming speed, forming speed and subsequent forming speed have a linear matching relationship.

[0025] Furthermore, the three circumferentially distributed rolling dies revolve around the center of the tube blank, while simultaneously rotating around their own dynamic center lines. In other words, the three rolling dies undergo an approximate planetary motion around the center line of the tube blank. After each rolling die completes one rotation, the two threads of the die advance one revolution, simultaneously completing the spinning of two corrugations. Based on this motion law, the relationship between the forming head rotation speed and the forming speed can be derived:

[0026]

[0027] In the formula:

[0028] N nThe rotational speed of the forming head in the nth pass is rpm;

[0029] D' is the outer diameter of the double helix curve screw tooth at the exit of the nth forming die, in mm;

[0030] n

[0031] P n The sum of the large and small wave pitches of the nth outlet bellows, in mm;

[0032] d n The diameter of the corrugated pipe trough at the exit of the nth rolling die, in mm;

[0033] K is the slip coefficient, taken as K = 0.95-0.98;

[0034] V n The forming speed for the nth pass is m / min.

[0035] Furthermore, as the double-corrugated tube advances during each rolling pass, the corrugation pitch P1 gradually decreases, resulting in a forming speed V1, a corrugation pitch P1, and a forming speed V of subsequent passes. n Wavelength P n The direct proportional relationship:

[0036]

[0037] In the above formula:

[0038] V1 is the first-pass corrugated pipe forming speed, in m / min;

[0039] P1 is the bellows pitch of the first exit bellows, in mm;

[0040] P n The outlet bellows pitch for the nth pass is in mm.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] This invention can effectively solve the transition problem between large and small waves during the double-wave forming process, making the large wave pitch and outer diameter larger, and the small wave pitch and outer diameter smaller, thereby significantly improving the bending fatigue life and mechanical properties of the double-wave corrugated pipe. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the overall structure of a continuous roll forming device for annular double-wave corrugated pipe proposed in this invention.

[0044] Figure 2 This is a schematic diagram of the bent structure of double-wave corrugated pipe A and single-wave corrugated pipe B;

[0045] Figure 3This is a schematic diagram illustrating the evolution of the double-wave corrugated pipe;

[0046] Figure 4 This is a schematic diagram of the rolling mechanism;

[0047] Figure 5 This is a schematic diagram illustrating the motion principle of roll forming.

[0048] Figure 6 This is a schematic diagram of the double-helix curve screw tooth structure on the outside of the 1-3 pass rolling die;

[0049] Figure 7 This is a schematic diagram of the double-helix curve screw tooth structure on the outside of the fourth rolling die;

[0050] Figure 8 This is a schematic diagram of the rolling process of the double-wave primary rolling mechanism I;

[0051] Figure 9 This is a schematic diagram of the rolling process of the double-wave primary rolling mechanism II;

[0052] Figure 10 This is a schematic diagram of the rolling process of the double-wave primary rolling mechanism III;

[0053] Figure 11 This is a schematic diagram of the rolling process of a double-wave finishing mill.

[0054] Figure 12 This is a schematic flowchart of a continuous roll forming method for annular double-wave corrugated pipe proposed in this invention.

[0055] Figure 13 This is a schematic diagram of the structure of various sizes of corrugated pipes formed by adjusting the parameters of the rolling die. Detailed Implementation

[0056] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0057] It should be noted that in the description of this invention, the terms "upper", "lower", "top", "bottom", "one side", "the other side", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention and simplifying the description, and do not mean that the device or element must have a specific orientation, or be constructed and operated in a specific orientation.

[0058] The continuous rolling forming device for annular double-corrugated pipes proposed in this embodiment adopts a four-pass continuous rolling forming process, involving U-shaped double-corrugated pipes such as... Figure 3 As shown, the outer diameter D of the large corrugated pipe 41 =17.1mm, wavelet outer diameter D 42 =16.1mm, wavelength P4=5.5mm, where the large wave wavelength P 41 =3.2mm, wavelet distance P 42 =2.3mm, valley diameter d4=12.2mm, wall thickness δ4=0.2mm, welding speed V0=1.8m / min, outer diameter of welded pipe φ15.4mm, forming speed V4=0.83m / min.

[0059] like Figure 1-11 As shown, the device specifically includes a cold bending roll group 2, a welding mechanism 9, a traction mechanism 3, and a rolling mechanism; the welding mechanism 9 is correspondingly located above the exit side of the cold bending roll group 2; the traction mechanism 3 is correspondingly located in front of the exit side of the cold bending roll group 2; the rolling mechanism is correspondingly located in front of the exit side of the traction mechanism 3; in this embodiment, the rolling mechanism includes a primary rolling mechanism I5, a primary rolling mechanism II6, a primary rolling mechanism III7, and a finishing rolling mechanism 8 arranged sequentially and evenly.

[0060] like Figure 4 As shown, the primary rolling mechanism I5, primary rolling mechanism II6, primary rolling mechanism III7, and finishing rolling mechanism 8 are all composed of three circumferentially distributed annular rolling dies, namely rolling die I10, rolling die II11, and rolling die III12. The outer side of each rolling die is surrounded by parallel double-helix curve screw teeth for rolling double-wave corrugated tubes. In this embodiment, the three circumferentially distributed rolling dies are all coaxially equipped with roller shafts 13 at their axial center positions, and the tail end of each roller shaft 13 is coaxially equipped with a synchronous gear 14. The three synchronous gears 14 are connected via a synchronous belt 15 to ensure the synchronous operation of the three rolling dies. The front end of each roller shaft 13 is connected to a rotary mechanism 16, which is correspondingly arranged on the base 19.

[0061] Among them, such as Figure 6 As shown, the double-helix curve screw teeth on the outer side of the rolling die of each primary rolling mechanism are designed with 1.5 turns of equal pitch, equal tooth thickness and equal outer diameter, and the tooth pitch of adjacent screw teeth is P′. n1 and P′ n2 Tooth pitch P′ n It is the sum of the pitches of adjacent teeth.

[0062] like Figure 7 As shown, the double-helix curve screw teeth on the outer side of the rolling die of the finishing rolling mechanism 8 adopt a combination design of variable pitch, variable tooth thickness, and variable outer diameter with 4 turns and 3 turns respectively; the tooth pitch of adjacent screw teeth is P′ respectively. 41 、P′42 、P′ 43 、P′ 44 、P′ 45 、P′ 46 、P′ 47 and P′ 48 .

[0063] Both the primary rolling mill and the finishing rolling mill are provided with an inlet guide sleeve 17 at their inlet sides; both the primary rolling mill and the finishing rolling mill are provided with an outlet guide sleeve 18 at their outlet sides.

[0064] A method for continuous roll forming of annular double-wave corrugated pipe, such as Figure 12 As shown, the specific steps include:

[0065] S1, such as Figure 1 As shown, the stainless steel strip 1 is rolled and welded sequentially through the cold bending roll group 2 and the welding mechanism 9 to obtain the thin-walled stainless steel longitudinal seam welded pipe 4 through online prefabrication.

[0066] S2, such as Figure 8 As shown, the thin-walled stainless steel longitudinal seam welded pipe 4 enters the primary rolling mechanism 1 at a speed of V0 = 1.8 m / min. Three circumferentially distributed rolling dies roll the inlet billet around the central axis O1--O1 at a rotation speed of N1 = 602 rpm. During the forming process, the inlet guide sleeve 17 and the outlet guide sleeve 18 provide circumferential constraints on the billet to ensure forming accuracy. The outlet speed of the billet is V1 = 1.6 m / min. The initial large and small wave billet 41 can be obtained through the pre-rolling of the primary rolling mechanism 1, wherein the outer diameter of the large wave is D. 11 =15.6mm, wavelet outer diameter D 12 =15.5mm, wavelength P1=10.6mm, large wave wavelength P 11 = 5.7mm, wavelet distance P 12 =4.9mm, valley diameter d1=14.5mm; the first screw tooth inlet valley point M1 reaches the valley point m1 after the rolling die rotates once, and the second screw tooth inlet point N1 reaches the valley point n1 after the rolling die rotates once. That is, two waves can be formed after the rolling die rotates once.

[0067] S3, such as Figure 9As shown, the initial large and small corrugated tube blank 41, formed in step S2, enters the primary rolling mechanism II6 at a speed of V1 = 1.6 m / min. Three circumferentially distributed rolling dies rotate around the central axis O2--O2 at a speed of N2 = 657 rpm to perform secondary rolling on the initial large and small corrugated tube blank 41. The exit speed of the corrugated tube is V2 = 1.48 m / min. The first screw tooth inlet needs to bite into the left trough M2 point of the large wave, and the second screw tooth inlet needs to bite into the left trough N2 point of the small wave. Through the rolling pressure of the three rolls and the extrusion of the adjacent two screw teeth, the double wave pitch can be further reduced and the trough depth can be deepened. The double corrugated tube blank 42 formed by the second rolling is characterized by the outer diameter D of the large wave. 21 =16.0mm, wavelet outer diameter D 22 =15.6mm, wavelength P2=9.8mm, large wave wavelength P 21 = 5.3mm, wavelet distance P 22 =4.5mm, valley diameter d2 =13.3mm.

[0068] S4, such as Figure 10 As shown, the double-wave tube blank 42, after being formed in step S3, enters the primary rolling mechanism III7 at a speed of V2 = 1.48 m / min. Three circumferentially distributed rolling dies rotate around the central axis O3-O3 at a speed of N3 = 702 rpm to perform a third rolling process on the inlet double-wave tube blank 42. The exit speed of the corrugated tube is V3 = 1.34 m / min. The first screw tooth inlet needs to first bite into the left trough M3 of the large wave, and the second screw tooth inlet needs to first bite into the left trough N3 of the small wave. The tube blank's wave pitch is further compressed and the troughs are further deepened after the three rolling processes, thus preparing it for the next precision rolling step. The double-wave tube blank 43, formed after the third rolling pass, has a large wave outer diameter D... 31 =16.4mm, wavelet outer diameter D 32 =15.7mm, wavelength P3=8.9mm, large wave wavelength P 31 = 4.9mm, wavelet distance P 32 =4.0mm, valley diameter d3=12.4mm.

[0069] S5, such as Figure 11 As shown, the double-wave tube blank 43 formed in step S4 enters the finishing rolling mechanism 8 at a speed of V3 = 1.34 m / min, and the exit speed of the tube blank 44 is V4 = 0.83 m / min. The forming roll is formed by two sets of spiral teeth with gradually varying tooth thickness, pitch, and outer diameter. When the double-wave tube blank 43 enters the finishing rolling mechanism 8, the first spiral tooth inlet needs to bite into the left trough M4 of the large wave, and the second spiral tooth inlet needs to bite into the left trough N4 of the small wave. Through the gradual shrinkage of multiple sets of pitches and trough rolling, a more rounded double-wave corrugated tube 44 is formed, in which the outer diameter D of the large wave is... 41=17.1mm, wavelet outer diameter D 42 =16.1mm, wavelength P4=5.5mm, large wave wavelength P 41 =3.2mm, wavelet distance P 42 =2.3mm, valley diameter d4=12.2mm.

[0070] Three circumferentially distributed rolling dies perform pure rolling spinning around the trough of the tube blank, and the forming speed, forming speed and subsequent forming speed have a linear matching relationship.

[0071] Three circumferentially distributed rolling dies revolve around the center of the tube blank, while simultaneously rotating on their own dynamic centerlines. This means the three rolling dies undergo an approximate planetary motion around the tube blank's centerline. After each complete one rotation, the two threads of the die advance one revolution, simultaneously completing the spinning of two corrugations. Based on this motion law, the relationship between the forming head rotation speed and the forming speed can be derived:

[0072]

[0073] In the formula:

[0074] N n The rotational speed of the forming head in the nth pass is rpm;

[0075] D' n The outer diameter of the double helix curve screw tooth at the exit of the nth forming die is in mm;

[0076] P n The sum of the large and small wave pitches of the nth outlet bellows, in mm;

[0077] d n The diameter of the corrugated pipe trough at the exit of the nth rolling die, in mm;

[0078] K is the slip coefficient, taken as K = 0.95-0.98;

[0079] V n The forming speed for the nth pass is m / min.

[0080] As the double-corrugated tube progresses through each rolling pass, the corrugation pitch P1 gradually decreases, resulting in a relationship between the forming speed V1, the corrugation pitch P1, and the forming speed V of subsequent passes. n Wavelength P n The direct proportional relationship:

[0081]

[0082] In the above formula:

[0083] V1 is the first-pass corrugated pipe forming speed, in m / min;

[0084] P1 is the bellows pitch of the first exit bellows, in mm;

[0085] P n The outlet bellows pitch for the nth pass is in mm.

[0086] Table 1. Dimensional parameters of bellows for each pass.

[0087]

[0088] Table 2. Parameters of double-helix curve screw teeth for 1-3 passes of rolling mill

[0089]

[0090]

[0091] Table 3. Parameters of the double-helix curve screw teeth for the fourth pass rolling die.

[0092]

[0093] Table 41-4 Relationship between Forming Speed ​​and Rotation Speed ​​in Passes

[0094]

[0095] Using the double-helix curve screw tooth parameters in Tables 2 and 3 and the forming speed parameters in Table 4, the special corrugated pipe with large and small waves in Table 1 can be formed by following steps S1-S5 for pipe welding, traction, three-pass initial rolling and finishing rolling. This can significantly improve the bending fatigue and mechanical properties of the double-wave corrugated pipe.

[0096] This invention is not limited to a single type of double-corrugated pipe; it can also be achieved by varying the helical tooth curve, tooth thickness, and outer diameter of the rolling die, such as... Figure 13 The diagram shows the forming of various corrugated pipes with different wave sizes, such as two small waves and one large wave, three small waves and one large wave, and one small wave and two large waves, to meet the needs of different working conditions.

[0097] All matters not covered in this invention are common knowledge.

[0098] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A continuous roll forming apparatus for annular double-wave corrugated pipes, characterized in that: The device includes a cold bending roll group, a welding mechanism, a traction mechanism, and a rolling mechanism; the welding mechanism is correspondingly located above the exit side of the cold bending roll group; the traction mechanism is correspondingly located in front of the exit side of the cold bending roll group; the rolling mechanism is correspondingly located in front of the exit side of the traction mechanism; the rolling mechanism includes three sets of primary rolling mechanisms and one set of finishing rolling mechanisms arranged in sequence and evenly. Both the primary rolling mechanism and the finishing rolling mechanism are composed of three circumferentially distributed annular rolling dies, and the outer side of the rolling dies is surrounded by parallel double-helix curve screw teeth for rolling corrugated tubes; the three circumferentially distributed rolling dies are all coaxially equipped with roller shafts at their axial center positions, and each roller shaft is coaxially equipped with a synchronous gear at its tail end. The three synchronous gears are connected by a synchronous belt to ensure the synchronous operation of the three rolling dies; and each roller shaft is connected to a rotary mechanism at its front end. The double-helix curve screw teeth on the outer side of the rolling die of the primary rolling mechanism are all designed with 1.5 turns of equal pitch, equal tooth thickness, and equal outer diameter. The tooth pitch of adjacent screw teeth is as follows: and ; The double-helix curve screw teeth on the outer side of the rolling die of the finishing mill adopt a combination design of variable pitch, variable tooth thickness, and variable outer diameter with 4 turns and 3 turns respectively; the tooth pitch of adjacent screw teeth are respectively , , , , , , and ; In the double-helix curve screw teeth on the outer side of the first pass primary rolling mechanism's rolling die. It is 5.7mm. The thickness is 4.9mm; in the double-helix curve screw teeth on the outer side of the rolling die of the second primary rolling mechanism, It is 5.3mm. The thickness is 4.5mm; in the double-helix curve screw teeth on the outer side of the rolling die of the third primary rolling mechanism, It is 4.9mm. The thickness is 4.0mm; the inner diameter of the double helical curve screw teeth on the outer side of the three sets of primary rolling mechanism roll dies is 50.5mm, the outer diameter is 55mm, and the tooth thickness is 0.75mm. In the double-helix curve screw teeth on the outer side of the finishing rolling die, The diameter is 4.9mm, the inner diameter is 49.5mm, the outer diameter is 54.7mm, and the tooth thickness is 0.7mm; The diameter is 4.0mm, the inner diameter is 49.5mm, the outer diameter is 54.7mm, and the tooth thickness is 0.75mm; The diameter is 4.4mm, the inner diameter is 49.5mm, the outer diameter is 54.8mm, and the tooth thickness is 0.80mm; The tooth diameter is 3.5mm, the inner diameter is 49.5mm, the outer diameter is 54.8mm, and the tooth thickness is 0.85mm. The diameter is 3.9mm, the inner diameter is 49.5mm, the outer diameter is 54.9mm, and the tooth thickness is 0.90mm; The diameter is 3.0mm, the inner diameter is 49.5mm, the outer diameter is 54.9mm, and the tooth thickness is 0.95mm; The tooth diameter is 3.2mm, the inner diameter is 49.5mm, the outer diameter is 55.0mm, and the tooth thickness is 1.00mm; It has a diameter of 2.3mm, an inner diameter of 49.5mm, an outer diameter of 55.0mm, and a tooth thickness of 1.00mm.

2. The continuous roll forming apparatus for annular double-wave corrugated pipes according to claim 1, characterized in that: Guide sleeves are provided on the inlet and outlet sides of the primary rolling mill and the finishing rolling mill.

3. The forming method of the annular double-wave corrugated pipe continuous roll forming device according to claim 1, characterized in that, Includes the following steps: S1. Stainless steel strips are passed sequentially through a cold bending roller group and a welding mechanism to prefabricate thin-walled stainless steel longitudinal seam welded pipes online. S2. The thin-walled stainless steel welded pipe is fed into the first set of initial rolling mechanism by the traction mechanism, and the initial three-roll rolling of the thin-walled stainless steel pipe is carried out according to the predefined parallel double helix curve screw teeth to preform the double wave square tube blank. S3. The pre-formed double-wave square tube blank in step S2 is fed into the second set of primary rolling mechanism, and the trough-deep rolling and peak extrusion are performed according to the predefined parallel double-helix curve screw teeth to pre-form the double-wave square tube blank. S4. The pre-formed double-wave square tube blank in step S3 is fed into the third set of primary rolling mechanism, and the valley and peak of the wave are further pressed and extruded according to the predefined parallel double-helix curve screw teeth to pre-form the double-wave square tube blank. S5. The pre-formed double-wave square tube blank from step S4 is fed into the finishing rolling mechanism. The tube blank is then subjected to final finishing rolling and straightening according to the predefined parallel double-helix curve screw teeth with variable outer diameter, variable pitch, and variable tooth thickness to form a precision double-wave corrugated tube.

4. The forming method of the annular double-wave corrugated pipe continuous roll forming device according to claim 3, characterized in that: Three circumferentially distributed rolling dies perform pure rolling spinning around the trough of the tube blank, and the forming speed, forming speed and subsequent forming speed have a linear matching relationship.

5. The forming method of the annular double-wave corrugated pipe continuous roll forming device according to claim 3, characterized in that: Three circumferentially distributed rolling dies revolve around the center of the tube blank, while simultaneously rotating on their own dynamic centerlines. This means the three rolling dies undergo an approximate planetary motion around the tube blank's centerline. After each complete one rotation, the two threads of the die advance one revolution, simultaneously completing the spinning of two corrugations. Based on this motion law, the relationship between the forming head rotation speed and the forming speed can be derived: ； In the formula: The rotational speed of the forming head in the nth pass is rpm; The outer diameter of the double helix curve screw tooth at the exit of the nth forming die is in mm; The sum of the large and small wave pitches of the nth outlet bellows, in mm; The diameter of the corrugated pipe trough at the exit of the nth rolling die, in mm; K The slip coefficient is taken as K = 0.95-0.98; The forming speed for the nth pass is m / min.

6. The forming method of the annular double-wave corrugated pipe continuous roll forming device according to claim 5, characterized in that: The double-corrugated tube advances with each pass of roll forming, and the corrugation pitch of the corrugated tube... P 1. The speed gradually decreases as the rolling passes proceed, thus forming the forming speed. V 1. Wavelength P 1. Forming speed of subsequent passes V n Wavelength P n The direct proportional relationship: ; In the above formula: V 1 represents the first-pass corrugated pipe forming speed, in m / min; P 1 represents the corrugated pitch of the first exit bellows, in mm; P n The outlet bellows pitch for the nth pass is in mm.

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